Error analysis of a continuous-discontinuous Galerkin finite element method for generalized 2D vorticity dynamics

A detailed a priori error estimate is provided for a continuous-discontinuous Galerkin finite element method suitable for two-dimensional geophysical flows. Special attention is given to derive estimates which require only minimal smoothness in the vorticity field

Hydraulic flow through a channel contraction: multiple steady states

We have investigated shallow water flows through a channel with a contraction by experimental and theoretical means. The horizontal channel consists of a sluice gate and an upstream channel of constant width $b_0$ ending in a linear contraction of minimum width $b_c$. Experimentally, we observe upstream steady and moving bores/shocks, and oblique waves in the contraction, as single and multiple steady states, as well as a steady reservoir with a complex hydraulic jump in the contraction occurring in a small section of the $b_c/b_0$ and Froude number parameter plane. One-dimensional hydraulic theory provides a comprehensive leading-order approximation, in which a turbulent frictional parametrization is used to achieve quantitative agreement. An analytical and numerical analysis is given for two-dimensional supercritical shallow water flows. It shows that the one-dimensional hydraulic analysis for inviscid flows away from hydraulic jumps holds surprisingly well, even though the two-dimensional oblique hydraulic jump patterns can show large variations across the contraction channel

Optimization of roll mechanical profiles in a continuous annealing line for steel strips

In order to set the mechanical characteristics to the target of the customer, cold rolled steel strips are annealed at high temperature in batch or continuous annealing furnaces.In a continuous annealing furnace, the strip passes over thermally deformed rollers. The shape of the furnace rollers at high temperature depends on this thermal deformation and on a mechanical profile on the roll. An accurate setting of the mechanical roller profiles is of major importance in order to avoid tracking problems, specially in the first part of the furnace, or buckling problems when the strip is wide and processed at high temperature.Since the last 15 years, the part of the strips processed in the continuous annealing lines is dramatically increasing in the world; the products are also getting thinner and wider and the processing speeds higher, causing lateral strip displacement and strip deformations, like buckles, more critical.In this context, it was important to accurately estimate the thermal deformation of the rollers and the critical conditions for buckling. JRSID and SOLLAC developed calculation models of roller thermal expansion, and wrinkling criteria. Those models were used to set new values of mechanical profiles for rollers in the annealing furnaces of SOLLAC

The potential of water markets to allocate water between industry, agriculture, and public water utilities as an adaptation mechanism to climate change

One of the climate change scenarios that have been developed for the Netherlands predicts hotter and drier summers and a substantial drop in river discharge. This might lead to water scarcity with detrimental economic and environmental effects. Among the possible adaptation responses to climate change-induced water scarcity, the re-allocation of water resources among competing uses should also be considered. In this paper, we extend and apply a computable general equilibrium (CGE) model to assess the potential of water markets (water allocation according to its shadow price) to guide the allocation of scarce water across agriculture, manufacturing, and public water supply. We develop four scenarios in which the scope of water markets is increased from industry-specific to economy-wide. The results show that the agricultural sector bears nearly all of the losses from a new water-scarce climate, while the manufacturing sectors are able to mitigate their losses to a large extent by technical measures. Extending the scope of water markets unambiguously increases economic output and results in a re-allocation of water to the manufacturing sector from the agricultural sector and from public water services. If, perhaps for political reasons, public water services are excluded from water trading, water is re-allocated from agriculture to manufacturing. Depending on which sectors are included, the construction of a water market can have negative or positive effects on a sector’s output, and although the implementation of water markets may be positive for overall economic output and can hence assist adaptation, the effect on vulnerable or societally sensitive economic sectors, such as public water, should be taken into account when implementing such a market

Measurement and prediction of the centering effect of a profiled roll on steel strips

In a steel continuous processing line, the strip passes over an important number of rolls and strip walking can occur due to strip defects, roll profile or roll misalignment. Since decades, two solutions are used in order to keep a strip centered in the line : deflection rolls are profiled (with crowned or tapered shapes) and steering rolls are implemented, in different part of the lines.As in other industries, the constant challenge for a line manager in the steel industry is to increase the productivity of the line and to adapt the lines to new products.To achieve these goals on pickling lines or continuous annealing lines, it is necessary in some cases to know precisely about the centering effect of profiled rolls on the strip. This data can be used either to improve the strip centering by increasing the roll profile or to avoid other defects as wrinkles, by reducing the crown without increasing strip walking.In order to quantify the centering efficiency of a roll, Irsid and Sollac developed a theoretical model for calculating the strip position after a profiled roll and compared it to experimental data measured on two pilot lines

On-The-Fly Processing of continuous high-dimensional data streams

[EN] A novel method and software system for rational handling of time series of multi-channel measurements is presented. This quantitative learning tool, the On-The-Fly Processing (OTFP), develops reduced-rank bilinear subspace models that summarise massive streams of multivariate responses, capturing the evolving covariation patterns among the many input variables over time and space. Thereby, a considerable data compression can be achieved without significant loss of useful systematic information. The underlying proprietary OTFP methodology is relatively fast and simple it is linear/bilinear and does not require a lot of raw data or huge cross-correlation matrices to be kept in memory. Unlike conventional compression methods, the approach allows the high-dimensional data stream to be graphically interpreted and quantitatively utilised in its compressed state. Unlike adaptive moving-window methods, it allows all past and recent time points to be reconstructed and displayed simultaneously. This new approach is applied to four different case-studies: (i) multi-channel Vis-NIR spectroscopy of the Belousov Zhabotinsky reaction, a complex, ill understood chemical process; (ii) quality control of oranges by hyperspectral imaging; (iii) environmental monitoring by airborne hyperspectral imaging; (iv) multi-sensor process analysis in the petrochemical industry. These examples demonstrate that the OTFP can automatically develop high-fidelity subspace data models, which simplify the storage/transmission and the interpretation of more or less continuous time series of high-dimensional measurements to the extent there are covariations among the measured variables.This research work was partially supported by the Spanish Ministry of Economy and Competitiveness under the project DPI2014-55276-C5-1R, Shell Global Solutions International B.V. (Amsterdam, The Netherlands), Idletechs AS (Trondheim, Norway), the Norwegian Research Council (Grant 223254) through the Centre of Autonomous Marine Operations and Systems (AMOS) at the Norwegian University of Science and Technology (Trondheim, Norway) and the Ministry of Education, Youth and Sports of the Czech Republic (CENAKVA project CZ.1.05/2.1.00/01.0024 and CENAKVA II project L01205 under the NPU I program). The authors want to acknowledge Prof. Bjorn Alsberg for providing the Vis-NIR equipment and the Laboratorio de Sistemas e Tecnologia Subaquatica of the University of Porto, the Hydrographic Institute of the Portuguese Navy and the University of the Azores for carrying out the REP15 exercise, during which the hyperspectral push broom image was collected.Vitale, R.; Zhyrova, A.; Fortuna, JF.; De Noord, OE.; Ferrer, A.; Martens, H. (2017). On-The-Fly Processing of continuous high-dimensional data streams. Chemometrics and Intelligent Laboratory Systems. 161:118-129. doi:10.1016/j.chemolab.2016.11.003S11812916

Onno) Omta and Frances T

Abstract This paper aims to analyze the effectiveness of the different cluster organization functions (services, activities and information sources) of Food Valley Organization in the Dutch agifood innovation system, as evaluated by its member companies. It is concluded that, in accordance with cluster organization theory, the networking formation function is the most important one, next demand articulation and innovation process management. However, our findings indicate that also visionary leadership, regional development and internationalization, stimulating entrepreneurial experimentation and providing downstream (market) information should be included in future analyses of cluster organization functions in innovation systems

University students and HIV in Namibia: an HIV prevalence survey and a knowledge and attitude survey

<p>Abstract</p> <p>Background</p> <p>With an overall adult HIV prevalence of 15.3%, Namibia is facing one of the largest HIV epidemics in Africa. Young people aged 20 to 34 years constitute one of the groups at highest risk of HIV infection in Namibia. However, little is known about the impact of HIV on this group and its access to healthcare. The purpose of this study was to estimate HIV prevalence, to assess the knowledge of and attitudes towards HIV/AIDS, and to assess access to healthcare among university students in Namibia.</p> <p>Methods</p> <p>We assessed HIV/AIDS knowledge and attitudes, HIV prevalence and access to healthcare among students at the Polytechnic of Namibia and the University of Namibia. HIV prevalence was tested through anonymous oral fluid-based tests.</p> <p>Results</p> <p>Half (n = 2790/5568) of the university students and 45% (n = 2807/6302) of the Polytechnic students participated in the knowledge and attitudes surveys. HIV/AIDS knowledge was reasonable, except for misperceptions about transmission. Awareness of one's own HIV status and risks was low. In all, 55% (n = 3055/5568) of university students and 58% (n = 3680/6302) of Polytechnic students participated in the HIV prevalence survey; 54 (1.8%) university students and 103 (2.8%) Polytechnic students tested HIV positive. Campus clinics were not the major providers of healthcare to the students.</p> <p>Conclusions</p> <p>Meaningful strategies addressing the gap between knowledge, attitude and young people's perception of risk of HIV acquisition should be implemented. HIV prevalence among Namibian university students appears relatively low. Voluntary counselling and testing should be stimulated. Efforts should be made to increase access to healthcare through the campus clinics.</p