A PDE-constrained optimization formulation for discrete fracture network flows

We investigate a new numerical approach for the computation of the 3D flow in a discrete fracture network that does not require a conforming discretization of partial differential equations on complex 3D systems of planar fractures. The discretization within each fracture is performed independently of the discretization of the other fractures and of their intersections. Independent meshing process within each fracture is a very important issue for practical large scale simulations making easier mesh generation. Some numerical simulations are given to show the viability of the method. The resulting approach can be naturally parallelized for dealing with systems with a huge number of fractures

A Fast, Affordable, Science and Technology SATellite (FASTSAT) and the Small Satellite Market Development Environment

The National Aeronautics and Space Administr ation at Marshall Space Flight Center and the National Space Science and Technology Center in Huntsville Alabama USA, are jointly developing a new class of science and technology mission small satellites. The Fast, Affordable, Science and Technology SATell ite (FASTSAT) was designed and developed using a new collaborative and best practices approach. The FASTSAT development, along with the new class of low cost vehicles currently being developed, would allow performance of ~ 30 kg payload mass missions for a cost of less than 10 million US dollars

The Development of a Remote Sensor System and Decision Support Systems Architecture to Monitor Resistance Development in Transgenic Crops

The United States Environmental Protection Agency (EPA) has declared that "significant benefits accrue to growers, the public, and the environment" from the use of transgenic pesticidal crops due to reductions in pesticide usage for crop pest management. Large increases in the global use of transgenic pesticidal crops has reduced the amounts of broad spectrum pesticides used to manage pest populations, improved yield and reduced the environmental impact of crop management. A significant threat to the continued use of this technology is the evolution of resistance in insect pest populations to the insecticidal Bt toxins expressed by the plants. Management of transgenic pesticidal crops with an emphasis on conservation of Bt toxicity in field populations of insect pests is important to the future of sustainable agriculture. A vital component of this transgenic pesticidal crop management is establishing the proof of concept basic understanding, situational awareness, and monitoring and decision support system tools for more than 133650 square kilometers (33 million acres) of bio-engineered corn and cotton for development of insect resistance . Early and recent joint NASA, US EPA and ITD remote imagery flights and ground based field experiments have provided very promising research results that will potentially address future requirements for crop management capabilities

Inventarisasi Fauna di Taman Kehati Lido, Bogor, Jawa Barat

PT. Tirta Investama-Plant Citeureup (PT. TIV-PC) merupakan perusahaan yang memproduksi air minum dalam kemasan (AMDK) dan telah meraih penghargaan lingkungan PROPER biru atas ketaatan berlebih melalui upaya konservasi keanekaragaman hayati. PT. TIV-PC telah mengembangkan Taman Keanekaragaman Hayati (Kehati) Lido sebagai sarana perlindungan sumber mata air yang menjadi bahan baku industrinya. Taman Kehati Lido (TKL) yang memiliki luar area 5.46 Ha telah memperkaya vegetasi yang ada dan mendukung kondisi habitat berbagai jenis satwa. Penelitian ini bertujuan memantau spesies fauna serta mempelajari struktur dan komposisi komunitas satwaliar di Taman Kehati Lido. Inventarisasi satwa menggunakan metode transek dengan menggunakan jalan dan sungai sebagai transek serta pemasangan jaring kabut (mist net) untuk mengamati semua spesies fauna. Burung diamati dengan metode IPA dan transek. Hasil penelitian ini menemukan 35 spesies satwa vertebrata (9 spesies mamalia, 18 spesies burung, 13 spesies herpetofauna, 4 spesies capung, dan 14 spesies kupu-kupu). Indeks keanekaragaman jenis total komunitas satwa adalah 3,5725 dan indeks kemerataan jenisnya 0,9767. Taman Kehati Lido (TKL) yang terletak di sekitar pabrik terbukti mampu menjadi habitat berbagai jenis satwa

Identification and characterization of the Non-race specific Disease Resistance 1 (NDR1) orthologous protein in coffee

<p>Abstract</p> <p>Background</p> <p>Leaf rust, which is caused by the fungus <it>Hemileia vastatrix </it>(Pucciniales), is a devastating disease that affects coffee plants (<it>Coffea arabica </it>L.). Disadvantages that are associated with currently developed phytoprotection approaches have recently led to the search for alternative strategies. These include genetic manipulations that constitutively activate disease resistance signaling pathways. However, molecular actors of such pathways still remain unknown in <it>C. arabica</it>. In this study, we have isolated and characterized the coffee <it>NDR1 </it>gene, whose <it>Arabidopsis </it>ortholog is a well-known master regulator of the hypersensitive response that is dependent on coiled-coil type R-proteins.</p> <p>Results</p> <p>Two highly homologous cDNAs coding for putative NDR1 proteins were identified and cloned from leaves of coffee plants. One of the candidate coding sequences was then expressed in the <it>Arabidopsis </it>knock-out null mutant <it>ndr1-1</it>. Upon a challenge with a specific strain of the bacterium <it>Pseudomonas syringae </it>(DC3000::<it>AvrRpt2</it>), analysis of both macroscopic symptoms and <it>in planta </it>microbial growth showed that the coffee cDNA was able to restore the resistance phenotype in the mutant genetic background. Thus, the cDNA was dubbed <it>CaNDR1a </it>(standing for <it>Coffea arabica Non-race specific Disease Resistance 1a</it>). Finally, biochemical and microscopy data were obtained that strongly suggest the mechanistic conservation of the <it>NDR1</it>-driven function within coffee and <it>Arabidopsis </it>plants. Using a transient expression system, it was indeed shown that the CaNDR1a protein, like its <it>Arabidopsis </it>counterpart, is localized to the plasma membrane, where it is possibly tethered by means of a GPI anchor.</p> <p>Conclusions</p> <p>Our data provide molecular and genetic evidence for the identification of a novel functional <it>NDR1 </it>homolog in plants. As a key regulator initiating hypersensitive signalling pathways, <it>CaNDR1 </it>gene(s) might be target(s) of choice for manipulating the coffee innate immune system and achieving broad spectrum resistance to pathogens. Given the potential conservation of <it>NDR1</it>-dependent defense mechanisms between <it>Arabidopsis </it>and coffee plants, our work also suggests new ways to isolate the as-yet-unidentified <it>R</it>-gene(s) responsible for resistance to <it>H. vastatrix</it>.</p

From invasion percolation to flow in rock fracture networks

The main purpose of this work is to simulate two-phase flow in the form of immiscible displacement through anisotropic, three-dimensional (3D) discrete fracture networks (DFN). The considered DFNs are artificially generated, based on a general distribution function or are conditioned on measured data from deep geological investigations. We introduce several modifications to the invasion percolation (MIP) to incorporate fracture inclinations, intersection lines, as well as the hydraulic path length inside the fractures. Additionally a trapping algorithm is implemented that forbids any advance of the invading fluid into a region, where the defending fluid is completely encircled by the invader and has no escape route. We study invasion, saturation, and flow through artificial fracture networks, with varying anisotropy and size and finally compare our findings to well studied, conditioned fracture networks.Comment: 18 pages, 10 figure

An optimization approach for large scale simulations of discrete fracture network flows

In recent papers the authors introduced a new method for simulating subsurface flow in a system of fractures based on a PDE-constrained optimization reformulation, removing all difficulties related to mesh generation and providing an easily parallel approach to the problem. In this paper we further improve the method removing the constraint of having on each fracture a non empty portion of the boundary with Dirichlet boundary conditions. This way, Dirichlet boundary conditions are prescribed only on a possibly small portion of DFN boundary. The proposed generalization of the method in relies on a modified definition of control variables ensuring the non-singularity of the operator on each fracture. A conjugate gradient method is also introduced in order to speed up the minimization proces

The virtual element method for discrete fracture network simulations

In this work, an optimization based approach presented in previous work of the authors for Discrete Fracture Network simulations is coupled with the Virtual Element Method (VEM) for the space discretization of the underlying Darcy law. The great flexibility of the VEM in allowing rather general polygonal elements, allow to easily describe irregular solutions starting from a general triangulation which can be built independently of the mesh on other fractures. Only a partial conformity is in fact obtained with this approach. Numerical results performed on several DFN configurations confirm the viability and efficiency of the resulting method

Coupling 3D Geomechanics to Classical Petroleum System Simulation

Geomechanical models of classical petroleum system simulators are limited to 1D phenomenological laws relating porosity to vertical effective stress. In order to overcome this limitation, a 3D poromechanical model is integrated in the sedimentary basin simulation by applying an iterative coupling scheme between a conventional basin code and a mechanical finite element code. This paper presents the porous material constitutive law specifically devised to deal with basin modeling, together with essential aspects of the mechanical code implementation and explicit coupling workflow. The numerical procedure is first verified according to a semi-analytical solution and then compared to an implicit academic code. Finally, a 3D synthetic case demonstrates the importance of incorporating 3D geomechanics to basin simulation. The results show that tectonic compression may significantly contribute to overpressure development and natural fracturing of seal rocks, contrary to the standard procedures of petroleum system simulation which are unable to capture such effect