Space-time discontinuous Galerkin discretization of rotating shallow water equations on moving grids

A space-time discontinuous Galerkin (DG) discretization is presented for the (rotating) shallow water equations over varying topography. We formulate the space-time DG finite element discretization in an efficient and conservative discretization. The HLLC flux is used as numerical flux through the finite element boundaries. When discontinuities are present, we locally apply dissipation around these discontinuities with the help of Krivodonova's discontinuity indicator such that spurious oscillations are suppressed. The non-linear algebraic system resulting from the discretization is solved using a pseudo-time integration with a second-order five-stage Runge-Kutta method. A thorough verification of the space-time DG finite element method is undertaken by comparing numerical and exact solutions. We also carry out a discrete Fourier analysis of the one dimensional linear rotating shallow water equations to show that the method is unconditionally stable with minimal dispersion and dissipation error. The numerical scheme is validated in a novel way by considering various simulations of bore-vortex interactions in combination with a qualitative analysis of PV generation by non-uniform bores. Finally, the space-time DG method is particularly suited for problems where dynamic grid motion is required. To demonstrate this we simulate waves generated by a wave maker and verify these for low amplitude waves where linear theory is approximately valid

Solid Freeform Fabrication Research In Engineering Education

Because Solid Freeform Fabrication (SFF) has an extremely wide range of potential applications, crossing traditional engineering and science boundaries, it is a technology that lends itself to multi-disciplinary activities and projects. SFF is an ideal mechanism to present scientific concepts including materials science and mechanics, as well as larger-scope engineering topics such as agile manufacturing. At Milwaukee School of Engineering (MSOE), we are using SFF technologies as a means to teach engineering concepts to undergraduate students through multidisciplinary research. MSOE was awarded a five-year grant under the NSF Research Experiences for Undergraduates Program (EEC-9619715) to facilitate student exploration in the field of Solid Freeform Fabrication. Sixty undergraduates will participate in summer and academic year programs by the year 2001. Eighteen students from around the country have participated in the program to date, bringing with them a diverse background of university experience, skill level, and interests. Working closely with a faculty advisor possessing expertise in a particular research area, they have performed research on Solid Freeform Fabrication applications in the biomedical, aerospace, architectural, manufacturing, and electronics industries. Some ofthe keys to the success of this program include: • Hands-on access to Solid Freeform Fabrication equipment through the facilities ofthe MSOE Rapid Prototyping Center (SLA 250, LOM 2030, and FDM 1650). • Close partnerships of the students with faculty and industry mentors in specialized areas of expertise. • Teaming with other educational institutions. • Significant cross-pollination between projects; faculty from diverse departments. • Encouraging students to publish and present results at national conferences and symposia.Mechanical Engineerin

Space-time discontinuous Galerkin finite element method for shallow water flows

A space-time discontinuous Galerkin (DG) finite element method is presented for the shallow water equations over varying bottom topography. The method results in non-linear equations per element, which are solved locally by establishing the element communication with a numerical HLLC flux. To deal with spurious oscillations around discontinuities, we employ a dissipation operator only around discontinuities using Krivodonova's discontinuity detector. The numerical scheme is verified by comparing numerical and exact solutions, and validated against a laboratory experiment involving flow through a contraction. We conclude that the method is second order accurate in both space and time for linear polynomials.\u

Experimental structure determination of the chemisorbed overlayers of chlorine and iodine on Au{111}

We have performed an experimental structure determination of the ordered p(sqrt[3] x sqrt[3])R30 degrees structures of chlorine and iodine on Au{111} using low-energy electron diffraction (LEED). Despite great similarities in the structure of the underlying substrate, which shows only minor deviations from the bulk positions in both cases, chlorine and iodine are found to adsorb in different adsorption sites, fcc and hcp hollow sites, respectively. The experimental Au-Cl and Au-I bond lengths of 2.56 and 2.84 A are close to the sums of the covalent radii, supporting the view that the bond is essentially covalent in nature; however, they are significantly shorter than predicted theoretically

Socio-Economic Impact of Bt Cotton — A Case Study of Karnataka

The performance Bt technology and its impact on farming community have been assessed in northern Karnataka based mainly on primary data processed using production functions, decomposition analysis and logit model. On an average, per farm area under Bt cotton was 2.21 ha, accounting for 66 per cent of the total landholding. With a yield of 24 q/ha, Bt cotton has registered 31 per cent higher yield and 151 per cent higher net return over non-Bt, the net additional benefit being ` 18429/ha. The non-Bt cotton farmers use chemical fertilizers, organic manures and bullock labour excessively which result in a lower net returns. Technology has been found the major contributor to the total productivity difference between Bt and non- Bt cottons. Seed cost, yield of Bt cotton and cost of plant protection have been found to greatly influence the probability of adoption of Bt cotton. Non-availability of quality seeds and in required quantity have been identified as the most important factors constraining Bt technology adoption. The impact of Bt cotton, as perceived by the farmers, has been in terms of enhanced yield; reduced pest and disease incidence; increased income, employment, education and standard of living; and reduced health risk. To foster adoption, availability of quality and quantity of Bt cotton seed to farmers needs greater attention of development agencies, while researchers’ attention is called for incorporating resistance/ tolerance to Spodoptera and pink bollworms.Bt cotton, Bt technology, Bt crop, Karnataka, Agricultural and Food Policy, Q16, Q12,

Asynchronous glacier dynamics during the Antarctic Cold Reversal in central Patagonia

We present 14 new 10Be cosmogenic nuclide exposure ages quantifying asynchronous readvances during the Antarctic Cold Reversal from glaciers in the Baker Valley region of central Patagonia. We constrain glacier and ice-dammed palaeolake dynamics using a landsystems approach, concentrating on outlet glaciers from the eastern Northern Patagonian Icefield (NPI) and Monte San Lorenzo (MSL). Soler Glacier (NPI) produced lateral moraines above Lago Bertrand from 15.1 ± 0.7 to 14.0 ± 0.6 ka, when it dammed the drainage of Lago General Carrera/Buenos Aires through Río Baker at a bedrock pinning point. At this time, Soler Glacier terminated into the 400 m “Deseado” level of the ice-dammed palaeolake. Later, Calluqueo Glacier (MSL) deposited subaerial and subaqueous moraines in the Salto Valley near Cochrane at 13.0 ± 0.6 ka. These moraines were deposited in an ice-dammed palaeolake unified through the Baker Valley (Lago Chalenko; 350 m asl). The Salto Valley glaciolacustrine landsystem includes subaqueous morainal banks, ice-scoured bedrock, glacial diamicton plastered onto valley sides, perched delta terraces, kame terraces, ice-contact fans, palaeoshorelines and subaerial push and lateral moraines. Boulders from the subaqueous Salto Moraine became exposed at 12.1 ± 0.6 years, indicating palaeolake drainage. These data show an asynchronous advance of outlet glaciers from the Northern Patagonian Icefield and Monte San Lorenzo during the Antarctic Cold Reversal. These advances occurred during a period of regional climatic cooling, but differential moraine extent and timing of advance was controlled by topography and calving processes

Port-Hamiltonian formulation of shallow water equations with Coriolis force and topography

We look into the problem of approximating the shallow water equations with Coriolis forces and topography. We model the system as an infinite-dimensional port-Hamiltonian system which is represented by a non-constant Stokes-Dirac structure. We here employ the idea of using different finite elements for the approximation of geometric variables (forms) describing a distributed parameter system, to spatially discretize the system and obtain a lumped parameter port-Hamiltonian system. The discretized model then captures the physical laws of its infinite-dimensional couterpart such as conservation of energy. We present some preliminary numerical results to justify our claims

Characterization of nanoparticle transport through quartz and dolomite gravels by magnetic resonance imaging

Magnetic resonance imaging (MRI) has tremendous potential for revealing transport processes in engineered and geologic systems. Here, we utilize MRI to image nanoparticle (NP) transport through a saturated coarse-grained system. Commercially available paramagnetically tagged NPs are used; the paramagnetic tag making the NP visible to MRI. NP transport was imaged as NPs migrated through packed columns of quartz and dolomite gravel. Changes in T2-weighted image intensity were calibrated to provide fully quantitative maps of NP concentration at regular time intervals (T 2 being the spin–spin relaxation time of 1H nuclei). Transport of nanoparticles was significantly retarded in dolomite compared to quartz due to electrostatic attraction between nanoparticle and dolomite surfaces. NP concentration profiles were evaluated with the CXTFIT computer package to estimate nanoparticle transport parameters at multiple points along the length of the column. This provided temporally resolved parameters that standard breakthrough curve analysis cannot provide. Particle–surface interaction energy profiles were described through Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. While dispersion coefficients and fast deposition rate constant (k fast) were found to increase with distance, deposition rate constant (k) and collision efficiency (α) were found to decrease with distance. These length-dependant variations have significant scaling-up implications for transport models used to predict NP transport in natural and engineered coarse-grained systems, such as sustainable urban drainage systems and river beds

Port-Hamiltonian discretization for open channel flows

A finite-dimensional Port-Hamiltonian formulation for the dynamics of smooth open channel flows is presented. A numerical scheme based on this formulation is developed for both the linear and nonlinear shallow water equations. The scheme is verified against exact solutions and has the advantage of conservation of mass and energy to the discrete level

Does financial liberalisation reduce credit constraints: A study of firms in the Indian private corporate sector

The study analyses the determinants of investment of the private corporate manufacturing sector in India in the context of financial liberalization. Though financial liberalization is still on the way, based on the theoretical argument of financial liberalization and its limitations in the context of asymmetric information and market imperfections, such an analysis assumes significance. Because, in imperfect financial markets with asymmetric information, external funds are more expensive than internal funds and firms have to follow a hierarchy in which cheaper funds are preferable to more expensive ones and internal funds are the most preferred ones. We tested the hypothesis that whether financial liberalization had an impact on firms’ investment decisions with respect to cash flow and debt. The study found that small firms are facing financial market imperfections in the form of liquidity constraints since it is seen that credit constraints were not eliminated or relaxed for these firms. Against this, one surprising result is the positive and significant coefficient of debt-to-capital ratio for large firms irrespective of the financial liberalisation effect. From further enquiry we found that the positive and significant impact of debt on investment for large firms has changed once we estimate the model for large firms according other categories based on group and export orientation. It is seen that the positive and significant impact of debt does not hold for large non-group and non-exporting firms. On the other hand, the positive effect of debt remains the same for large group and exporting firms. To conclude, market imperfections exist in the financial markets that prevent an economy wide efficiency in the post liberalisation period.Information Asmmetry; Market Imperfection; Investment; Financing Pattern, Corporate Sector