Non-linear models for a gypsum kiln. A comparative analysis

INTERNATIONAL FEDERATION OF AUTOMATIC CONTROL. WORLD CONGRESS (15.2002.BARCELONA)This paper presents several non-linear models adjusted in order to capture the dynamics of a gypsum kiln. The behavior of this kind of processes is affected by nonlinear effects caused by the existence of disturbances and the coupling among some variables. The use of second order Volterra and Hammerstein models as appropriate solutions to describe the process dynamics is analyzed. A thorough study of the best model order and structure is performed. Coefficients that best fit real data are also selected. This work aims to obtain a good non-linear model in order to implement a non-linear predictive controller, able to improve the performances of those linear controllers already tested on the plant.Comisión Interministerial de Ciencia y Tecnología (CICYT) 1FD97-083

Oil in Colombia: History, Regulation and Macroeconomic Impact

Colombia´s oil history began in 1918 and reached its golden era at the end of the 1980s. Regulation in the oil industry changed several times since 1974, mainly responding to the discoveries made. Although agreed contract terms have been honored for oil fields allocated in the past, regulation instability has affected long term the relationships with private investors, since new conditions were imposed for future contracts. Once too onerous conditions, too low prices and international competition drove investors away from the country, regulation was softened. Recently, the Colombian government has improved contractual terms and made tributary and royalty conditions more attractive to private investors. The important discoveries made in the last two decades led Colombia to an expenditure spiral, paired with a huge fiscal deficit and a high public debt, drastically changing a seven decade long record of fiscal stability.The cycle of cheap-expensive oil has exhibited a full swing, and although exploration contracts and investment have increased, no important discoveries have been made, revealing a complicated geology that might pose a challenge to the country´s hydrocarbons´ self-sufficiency.oil, government policy and regulation, deficit, debt

Exploiting novel automated analytical methodologies for the monitoring of environmental organic pollutants, and its potential incorporation to environmental monitoring regulations

Se han desarrollado métodos analíticos basados en cromatografía y detección por espectrometría de masas para la detección de múltiples compuestos orgánicos a niveles traza en muestras de interés ambiental. Se han determinado compuestos volátiles en aire atmosférico de Mallorca y varias plantas de tratamiento de residuos y vertederos, y fármacos de consumo humano en muestras del medioambiente acuático de Mallorca, plantas de tratamiento de aguas y lixiviados de vertederos. Con estos datos se ha evaluado la necesidad de modificar los planes de vigilancia ambiental para asegurar la calidad del medioambiente de Mallorca.We have developed analytical methodologies based on chromatography and mass spectrometry for the detection of multiple different organic compounds in the trace levels in samples of environmental interest. Volatile organic compounds have been determined in the atmospheric air of Mallorca as well as some waste treatment plants and landfills. Pharmaceuticals for human consumption have been investigated in several samples of the aquatic environment of Mallorca as well as some wastewater treatment plants and landfill leachates. Based on these data it has been evaluated the necessity to modify the environmental monitoring regulations to save the quality of the Mallorca’s environment

Detector blinding attacks on counterfactual quantum key distribution

Counterfactual quantum key distribution protocols allow two sides to establish a common secret key using an insecure channel and authenticated public communication. As opposed to many other quantum key distribution protocols, part of the quantum state used to establish each bit never leaves the transmitting side, which hinders some attacks. We show how to adapt detector blinding attacks to this setting. In blinding attacks, gated avalanche photodiode detectors are disabled or forced to activate using bright light pulses. We present two attacks that use this ability to compromise the security of counterfactual quantum key distribution. The first is a general attack but technologically demanding (the attacker must be able to reduce the channel loss by half). The second attack could be deployed with easily accessible technology and works for implementations where single photon sources are approximated by attenuated coherent states. The attack is a combination of a photon number splitting attack and the first blinding attack which could be deployed with easily accessible technology. The proposed attacks show counterfactual quantum key distribution is vulnerable to detector blinding and that experimental implementations should include explicit countermeasures against it

Sexual dimorphism in bite performance drives morphological variation in chameleons

Phenotypic performance in different environments is central to understanding the evolutionary and ecological processes that drive adaptive divergence and, ultimately, speciation. Because habitat structure can affect an animal's foraging behaviour, anti-predator defences, and communication behaviour, it can influence both natural and sexual selection pressures. These selective pressures, in turn, act upon morphological traits to maximize an animal's performance. For performance traits involved in both social and ecological activities, such as bite force, natural and sexual selection often interact in complex ways, providing an opportunity to understand the adaptive significance of morphological variation with respect to habitat. Dwarf chameleons within the Bradypodion melanocephalum-Bradypodion thamnobates species complex have multiple phenotypic forms, each with a specific head morphology that could reflect its use of either open-or closed-canopy habitats. To determine whether these morphological differences represent adaptations to their habitats, we tested for differences in both absolute and relative bite performance. Only absolute differences were found between forms, with the closed-canopy forms biting harder than their open-canopy counterparts. In contrast, sexual dimorphism was found for both absolute and relative bite force, but the relative differences were limited to the closed-canopy forms. These results indicate that both natural and sexual selection are acting within both habitat types, but to varying degrees. Sexual selection seems to be the predominant force within the closed-canopy habitats, which are more protected from aerial predators, enabling chameleons to invest more in ornamentation for communication. In contrast, natural selection is likely to be the predominant force in the open-canopy habitats, inhibiting the development of conspicuous secondary sexual characteristics and, ultimately, enforcing their overall diminutive body size and constraining performance

Volterra Model Based Predictive Control, application to a Pem Fue Cell

14th Nordic Process Control Workshop - Espoo, Finland Duration: 23 Aug 2007 → 25 Aug 2007This paper presents a non linear model predictive controller for a PEM fuel cell for which the starvation control is the main objective. A second order Volterra model for control is obtained using input/output data for which the power supplied by the fuel cell is considered as a measurable disturbance. The controller developed allows to solve the nonlinear objective function in a way that it can be actually implemented in fast systems like Fuel cells. The use of a nonlinear controller is justified while comparing the outcome obtained with a linear controller of the same class

Physiology, environmental change, and anuran conservation

This paper reviews diverse ways in which the emerging discipline of conservation physiology may contribute to the conservation of anuran amphibians. We first present a summary of the goals of conservation physiology. Then, we review five specific sources of environmental change that are known to affect anurans: introduced pathogens (highlighting the case of chytridiomycosis) and exotic species, pollutants, habitat fragmentation, and global climate change. We discuss these types of environmental change in the context of how and why altered environments may become stressing to anurans and cause population declines. We also discuss synergism among variables that may worsen the effect of environmental alterations, and emphasize the importance of conservation physiology for Brazilian anurans

A Change Execution System for Enterprise Services with Compensation Support

Modern enterprises rely on a distributed IT infrastructure to execute their business processes, adopting Service Oriented Architectures in order to improve the flexibility and ease of adaptation of their functions. Nowadays this is a vital characteristic, as the increased competition forces companies to continuously evolve and adapt. SOA applications must be supported by management and deployment systems, which have to continuously apply modifications to the distributed infrastructure. This article presents a modelbased solution for automatically applying change plans to heterogeneous enterprise managed environments. The proposed solution uses models which describe in an abstract language the changes that need to be applied to the environment, and executes all the required operations to the specific managed elements. Also, to ensure that the environment ends in a stable state, compensation for previously executed operations is supported. The validation results from a case study taken from the banking domain are also presented here

Groups with infinitely many ends acting analytically on the circle

This article takes the inspiration from two milestones in the study of non minimal actions of groups on the circle: Duminy's theorem about the number of ends of semi-exceptional leaves and Ghys' freeness result in analytic regularity. Our first result concerns groups of analytic diffeomorphisms with infinitely many ends: if the action is non expanding, then the group is virtually free. The second result is a Duminy's theorem for minimal codimension one foliations: either non expandable leaves have infinitely many ends, or the holonomy pseudogroup preserves a projective structure.Comment: We can now make a precise reference to Deroin's work arXiv:1811.10298. 54 pages, 2 figure