Numerical optimization of an injection volumetric expander for use in waste heat recovery organic Rankine cycle

in Proceedings of the 7th International Conference on Compressors and their Systems (2011, September 05)

Waste heat recovery organic Rankine cycle (ORC) systems allow generating mechanical or electrical power from local low grade heat sources. This paper shows how the power produced by the system can be ... [more ▼]

Waste heat recovery organic Rankine cycle (ORC) systems allow generating mechanical or electrical power from local low grade heat sources. This paper shows how the power produced by the system can be increased by achieving several evaporating pressure levels and injecting low pressure flow during expansion. A numerical model of the vapour injection expansion is developed and different system configurations are compared. In comparison with a simple configuration of the cycle, vapour injection configuration yields a maximum increase of 16% of the power production. Moreover, the specific power can be increased by 26%, which would largely reduce the specific investment cost of the waste heat recovery system. [less ▲]

THERMAL ACCEPTABILITY ASSESSMENT IN VERNACULAR BUILDINGS OF COLD AND CLOUDY REGION OF NORTH-EAST INDIA

in 30th ISES Biennial Solar World Congress 2011, SWC 2011 (2011, September 02)

Thermal performance study is one of the critical aspects of the natural ventilated vernacular buildings. Thermal comfort studies of built environment mainly focussed on two different approaches, one is ... [more ▼]

Thermal performance study is one of the critical aspects of the natural ventilated vernacular buildings. Thermal comfort studies of built environment mainly focussed on two different approaches, one is heat balance approach and the other is adaptive approach. Thermal comfort survey has been carried out in 50 houses covering over 100 occupants of cold and cloudy climatic zone of North East India. This comfort study has been done in the form of long term thermal monitoring at outside and inside of a house, comfort survey based on ASHRAE thermal sensation scale for different seasons of the year. Comfort temperatures are calculated based on Humphreys and Auliciems comfort model. Neutral temperatures at which people feels comfortable in this natural ventilate buildings are obtained from the comfort survey. It has been found that the comfort temperature obtained from the Humphreys and Auliciems comfort model differs with the neutral temperatures obtained from comfort surevy. There are four major indicator like outdoor and indoor temperatures, relative humidity and clothing pattern of the peoples has direct impact on the peoples perception and acceptabilty on comfort situtaion. In this study, thermal comfort equations are developed based on these four indicator and validated with the neutral temperature obtained from comfort survey. It has been found that the comfort equation developed with all these four indicators has highest co-relation coefficient and provide the neutral temparture values very close to thermal comfort survey results. However, these equations are valid only for similar kinds of natural ventilated buildings and also for similar kinds of building functioning management of this climatic zones. It is also not appropriate to obtaine a genralized thermal comfort model as the adpation process and the expectation and perceptation of the peoples are region specific and also differs with socio-cultural norms. [less ▲]

Taking the vector vortex coronagraph to the next level for ground- and space-based exoplanet imaging instruments: review of technology developments in the USA, Japan, and Europe

in Shaklan, Stuart (Ed.) Techniques and Instrumentation for Detection of Exoplanets V. (2011, September 01)

The Vector Vortex Coronagraph (VVC) is one of the most attractive new-generation coronagraphs for ground- and space-based exoplanet imaging/characterization instruments, as recently demonstrated on sky at ... [more ▼]

The Vector Vortex Coronagraph (VVC) is one of the most attractive new-generation coronagraphs for ground- and space-based exoplanet imaging/characterization instruments, as recently demonstrated on sky at Palomar and in the laboratory at JPL, and Hokkaido University. Manufacturing technologies for devices covering wavelength ranges from the optical to the mid-infrared, have been maturing quickly. We will review the current status of technology developments supported by NASA in the USA (Jet Propulsion Laboratory-California Institute of Technology, University of Arizona, JDSU and BEAMCo), Europe (University of Li`ege, Observatoire de Paris- Meudon, University of Uppsala) and Japan (Hokkaido University, and Photonics Lattice Inc.), using liquid crystal polymers, subwavelength gratings, and photonics crystals, respectively. We will then browse concrete perspectives for the use of the VVC on upcoming ground-based facilities with or without (extreme) adaptive optics, extremely large ground-based telescopes, and space-based internal coronagraphs. [less ▲]

Agritourism at the crossroad of the socio-ecological European transition

in Girardot, J-J.; Devillet, G. (Eds.) Papers of the 10th Annual International Conference of Territorial Intelligence of INTI “Territorial Intelligence and Sustainable economics within the new culture of development (2011, September)

The resources of the rural countryside in Europe are subject to many pressures and the difficulties arising in many rural areas somehow jeopardise the agriculture: agricultural activities are decreasing ... [more ▼]

The resources of the rural countryside in Europe are subject to many pressures and the difficulties arising in many rural areas somehow jeopardise the agriculture: agricultural activities are decreasing and farmers are losing importance. The consequences of a reduction or even disappearance of the agricultural activity are varied and refer to social, economic, cultural and environmental domains like the disappearance of activities and services in rural area, the loss of a rural identity or impacts on particular landscapes. Difficulties relate to the pressures exerted on farmers: pressures due to the world competition, to the evolution from the spread of suburbanisation, to the tendency of young people to leave rural life, to transport problems in the rural areas. The socio-ecological transition may be seen as a track of diversification in farming activities. One of the solutions aiming to improve the rural economy in accordance with its natural and cultural heritages is the development of farm tourism also seen as a means for rural communities to link producers and consumers again strengthening the social capital. Agritourism is a soft form of tourism, which aims to promote the rural capital and which, by supporting the regional development, helps to improve the income of the regional population. It includes different types of accommodations (such as guest farm, bed and breakfast or camping on the farm) and multiple activities in rural areas through which the visitor has the opportunity to become acquainted with agricultural areas, agricultural occupations, local products, traditional cuisine and daily life, as well as with the cultural elements and the authentic features of the area, while showing respect for the environment and the tradition. Agritourism brings visitors closer to nature and rural activities in which they can participate. This form of tourism fits with new expectations as regards environmental, patrimonial and social matters of tourists in Europe. The lecture compares agritourism in the Walloon Region and in the Grand Duchy of Luxembourg, bordering regions which share a common aim to develop both a differentiated agriculture and a sustainable agritourism. The research develops a combination of several complementary procedures and tools: international comparison, on-site investigations near the stakeholders concerned by agritourism of which agritourist offer investigations near local tenants and farmers and agritourist demand investigations to potential customers, without forget investigations near organizations and institutions that attempt to influence its development, This lecture presents a kind of economic diversification, agritourism, of farms aiming to provide a global and integrated vision. Problems encounter because of the diversity of resources (infrastructures, goods and services) and stakeholders involved in multiple relations (tourists, tour operators, host community members, various organizations, industries...) imply innovative agritourist adaptations concerned by a tourist qualitative and wellbeing search. It proposes to define the necessary characteristic of the countryside, the ressources, to develop agritourism and to examine disparities of the agritourist developement, and to establish a typology of the countryside more or less favourable to its emergence, its development and its success taking into account the various forms of agritourism in Europe. It enlightens the general question entitled "Which countrysides for which agritourisms?”. The objective is thus to think an agritourism both thought out according to the paradigm of sustainable development, and conforming to the principles the ecological economy. [less ▲]

How clinical nutrition helps pets suffering from acute and chronic diseases- practical examples and prospects

in TSAVA (Ed.) 17th FECAVA Eurocongress 6th TSAVA Congress Modern Veterinary Practices Congress Book (2011, September)

Energy requirements and solar availability in suburban areas: the influence of built density in an existing district

in Proceedings of the International Conference CISBAT 2011 - Clean Tech for sustainable buildings - From Nano to urban scale (2011) (2011, September)

Although the environmental impacts of urban sprawl and their associated energy consumptions are now well documented, it remains a concern in many regions. In the current context of growing interest in ... [more ▼]

Although the environmental impacts of urban sprawl and their associated energy consumptions are now well documented, it remains a concern in many regions. In the current context of growing interest in environmental issues, local authorities become aware of this concern and are now trying to limit the development of new low-density suburban districts while households still continue to promote dispersed individual housing types located outside city centres. In this context, the paper proposes to investigate the influence of an increase in built density, in existing suburban neighbourhoods. The idea is to favour a higher built density in existing neighbourhoods instead of building new low-density neighbourhoods on unbuilt areas. The impacts of four renewal strategies dealing with the density are assessed, at the neighbourhood scale, for three indicators: (1) the potential energy savings for heating houses, (2) the solar energy received by the facades and roofs, as dispersed individual housing types are known to be those that receive most solar gains and (3) the potential area of land savings. [less ▲]

Epidemiology of mastitis in 30 walloon dairy farms using a compilation of clinical and subclinical data in a new tool for Udder health assessment

in Proceedings of the 6th European congress of Bovine health management (2011, September)

Bovine mastitis has been assessed through somatic cells or clinical cases by farmers and vets but most of the time the perfect combination of both data remains unavailable. We tried to implement a new ... [more ▼]

Bovine mastitis has been assessed through somatic cells or clinical cases by farmers and vets but most of the time the perfect combination of both data remains unavailable. We tried to implement a new strategy of identification of mastitis-related costs, epidemiological impact and key periods of management. We built an online system for clinical data capture, including facilities for administrative management of veterinary drugs. Herd prevalence rate (HPR) is assessed through clinical and subclinical data. Lactation incidence rate (NIR) and cure rate (CR) were calculated for the period (depending on type of DHI control) using subclinical thresholds (primiparous > 150.000 cells/ml and multiparous >250.000 cells/ml) and clinical cases in susceptible animals (healthy or diseased). Dry-off period is studied through the Dry-off cure rate (DOCR) and new infection rate at first control (NIFC). The average number of cow-day-at-risk was 73.6 (StD=34.80). Mean HPR was 33 % (StD =11%); the average NIR was 16% and CR 35%. Mean DOCR was 62% with an NIFC of 23%. Regarding a mean loss for mastitis of 71€ per cow-year, the average difference was +40.7€ (StD=66.7€). It is explained partly by DOCR (R²=0.20; β=-131; p<0.0001). NIR is mainly influenced by HPR, but mainly by primiparous infection rate (R²=0.36; β= 0.33; p<0.0001). Those figures are coherent with subclinical data indicating that multiparous cows are becoming more and more infected, limiting efficacy of dry-off therapy. Communication has to be done around dry-off and preventive measures in primiparous cows. As CR had few significant impact on global udder health, cure at the herd level should more be regarded as cow ability to cure in its environment than by considerations on medication once infected. [less ▲]

Evaluation of Eddy Losses Due to High Current Leads in Transformers Using a Subproblem Method

in ISEF 2011 - XV International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering (ISEF2011 ) (2011, September)

A subproblem finite element method is developed for evaluating the eddy losses due to high current leads in transformers. The structural component of the transformer is modeled with classical volumetric ... [more ▼]

A subproblem finite element method is developed for evaluating the eddy losses due to high current leads in transformers. The structural component of the transformer is modeled with classical volumetric elements or more efficiently with a thin shell model (surface impedance technique). Tools are then developed to correct the inaccuracies near edges and corners inherent to thin shell models for magnetodynamic problems. Improvements of local fields make possible accurate calculations of eddy losses and of temperature rise. [less ▲]

An Experimental Approach to Link Powder Physical Properties to 3D Particle Shape

in Particulate Systems Analysis 2011 (2011, September)

A series of samples have been characterized by 3D image analysis (using X-Ray microtomography). The samples consist of blends of metallic particles: steel shot abrasives (“balls”), steel fibres and ... [more ▼]

A series of samples have been characterized by 3D image analysis (using X-Ray microtomography). The samples consist of blends of metallic particles: steel shot abrasives (“balls”), steel fibres and angular steel grit particles. The blends were systematically prepared in different proportions of the raw products. Various shape and size parameters were measured on the particles: equivalent volume diameter (dV), maximum inscribed sphere diameter (dIN), particle length (maximum Feret diameter), particle elongation (El), particle flatness (Fl) etc. The results are expressed as statistical shape and size parameters, expressed both as volume and number weighted distributions. The blends have been tested for compaction using a cylindrical container which experiences a series of 500 free falls over a height of 3mm. The compaction dynamics was monitored using a sensor that measures the evolution of the solid volume fraction as a function of the tap number. From the obtained compaction curve, the Hausner ratio and a flowability index were extracted. The same blends have also been analysed using a rotating drum at different rotation speeds to analyze the evolution of the flowing angle. As the system is based on the analysis of a time sequence of 50 images (separated by 0.5 sec) it is possible to measure the intermittent character of the powder flow. The resulting measure is a cohesive index of the powder. The results obtained from physical testing were systematically plotted as a function of various statistical indices of the shape and size distributions in order to reveal correlations between particle shape properties and physical behaviour. Some clear trends appeared, demonstrating the influence of particle shape on powder physical properties. [less ▲]

An Efficient Dual and Triple Frequency Preprocessing Method for GALILEO and GPS Signals

in 3rd International Colloquium – Scientific and Fundamentals Aspects of the GALILEO Programme (2011, September)

Data preprocessing is a mandatory stage for most of GNSS applications. In the frame of space weather and precise point positioning applications, the Geomatics Unit of the University of Liège has purchased ... [more ▼]

Data preprocessing is a mandatory stage for most of GNSS applications. In the frame of space weather and precise point positioning applications, the Geomatics Unit of the University of Liège has purchased two Septentrio PolaRx3eG receivers which allow tracking GPS L1/L5 and Galileo E1/E5a signals. In order to fully exploit these new data, we developed a preprocessing method extending existing techniques. Our preprocessing method consists of three consecutive steps. The first step is devoted to the compensation of receiver clock slips affecting code pseudorange and carrier-phase measurements. The second step covers cycle slips detection and the third step assesses data quality in terms of noise essentially affecting code pseudorange measurements. This preprocessing method was initially developed for GPS L1/L5 and Galileo E1/E5a dual frequency data but finally enhanced to also preprocess triple frequency data from first operational Galileo satellites as soon as data are available. The developed method already showed promising results. [less ▲]

Discrete Event Production Simulation in Shipyard Workshops

in Proceeding of the 21th COPINAVAL (2011, September)

Nowadays, shipyards are making huge effort to efficiently manage equipments and resources such as laborers, gantry cranes, transporters, steel and block stock yards, etc. Previously scheduling was ... [more ▼]

Nowadays, shipyards are making huge effort to efficiently manage equipments and resources such as laborers, gantry cranes, transporters, steel and block stock yards, etc. Previously scheduling was manually performed by an experienced manager of a shipyard. But such a scenario leads to undesirably long times for producing scheduling results. In addition, the quality of the scheduling results was usually not optimal. To improve the overall process, Discrete Event Simulations (DES) have been developed and recently use in shipbuilding industry. The use of simulation-based design and virtual reality technologies leads to higher efficiency in terms of work strategy planning, and offers, as a result, significant productivity gains. It gives computer-supported answers to the major questions: when and where to produce what and with which resources depending on the availability and restrictions of resources and materials. The first part of the paper presents a multi-criteria analysis to select the most appropriate DES software for shipyards. Then, the second part of the paper shows production simulation model focusing on block erection stage. Two different blocks splitting are compared and then the results are discussed. [less ▲]

Total fat content and essential fatty acids profile in 46 dry dog foods

in Castrillo, Carlos (Ed.) Congress Proceedings 15th Congress ESVCN (2011, September)

La troponine T ultrasensible : un nouvel outil diagnostic pour le médecin sportif?

in 4ème Congrès commun SFMS & SFTS (2011, September)

Introduction : Le risque d’accidents cardiaques ou de mort subite après effort physique intense est bien connu. Ces évènements indésirables se produisent souvent chez des sujets présentant une maladie ... [more ▼]

Introduction : Le risque d’accidents cardiaques ou de mort subite après effort physique intense est bien connu. Ces évènements indésirables se produisent souvent chez des sujets présentant une maladie coronarienne asymptomatique et ignorée. Néanmoins, vu ce risque, l’American Heart Association recommande de réaliser un screening cardiovasculaire chez les athlètes de tout âge. Dans cette optique, le dosage de marqueurs cardiaques de nouvelle génération, plus sensibles, comme la troponine T ultrasensible (hsTnT) peut certainement apporter des informations très intéressantes par la détection de dommages myocardiques mêmes mineurs. Matériels et méthodes : Des 20 sujets masculins volontaires âgés de 22.36±2.02 années, sédentaires, 8 ont dû être exclus (abandon, malaise à l’effort...). La VO2max a été préalablement déterminée lors d’un test à l’effort sur cycloergomètre une semaine avant le test afin de ne pas interférer avec les résultats de l’effort physique intense (EPI) pour lequel les sujets ont couru sur tapis roulant durant 1 heure à 75% de la VO2max. Quatre échantillons sanguins de 5 ml (tube hépariné-lithium) ont été prélevés : juste avant (T1), directement après (T2), 4 heures après (T3) et 24 heures après l’EPI (T4). Le dosage de hsTnT (Modular de Roche Diagnostic®) est réalisé sur du plasma par une technique d’électrocheminiluminescence. Résultats : Une augmentation statistiquement significative des résultats à T3 (p<0.01) est observée. L’élévation de la hsTnT est progressive pour atteindre un pic maximum à T3 et revenir dans les normes à T4. Le seuil critique de 0.03 ng/mL a été retenu et 75% des sujets présentent un taux supérieur à ce dernier à T3 (moyenne : 0.053 ng/mL), alors que 100% des sujets se trouvent en dessous de ce seuil à T1 (0.0041 ng/mL). Discussion - Conclusions : Ces résultats, extrêmement intéressants, suggèrent que la libération de hsTnT serait due soit à un processus physiologique de remodelage, soit à un processus irréversible de lésions au niveau des cardiomyocytes (nécrose). Il est également possible que cette élévation des troponines soit due à une libération à partir du pool cytosolique mais aussi elle peut être la conséquence de dommages membranaires potentiellement induits par le stress oxydatif. A l’issue de cette étude, nous démontrons que la hsTnT peut être un nouvel outil diagnostic dans le domaine de la cardiologie du sport. [less ▲]

Non-dissipative joints in seismic resistant building frames - Bolted beam-to-column joints

in EUROSTEEL 2011 - 6th European Conference on Steel and Composite Structures - Proceedings (2011, September)

According to Eurocode 8, earthquake resistant steel building frames shall be designed following either the “low dissipative structural behaviour concept” or the “dissipative structural behaviour concept” ... [more ▼]

According to Eurocode 8, earthquake resistant steel building frames shall be designed following either the “low dissipative structural behaviour concept” or the “dissipative structural behaviour concept”. In the second concept, the capability of parts of the structure to resist earthquake actions through inelastic behaviour is taken into account: energy is dissipated in plastic mechanisms. In such a design, it has to be ensured that the dissipative zones form where they are intended to and that they yield before other zones leave the elastic range. In particular, moment resisting frames are designed in such a way that plastic hinges develop at the extremities of the beams. These dissipative zones can be located either in the beams or in the beam-to-column joints. In this paper, non-dissipative bolted beam-to-column connections are considered. They must be sufficiently resistant to remain in elastic range while cyclic yielding develops in the dissipative zones located in the beams. Besides, the possibility that the actual yield strength of the beam is higher than the nominal value has to be taken into account by a material overstrength factor. Such an approach generally leads to very strong and thus expensive joints. In the present paper, a design strategy leading to more economical solutions for full-strength beam-to-column joints is detailed. This study was conducted within the framework of an RFCS project called HSS-SERF (High Strength Steel in Seismic Resistant Building Frames). The considered moment-resisting joints are part of seismic resistant building frames made of high strength steel composite columns and mild carbon steel beams. The columns are either partially-encased wide-flange columns (H columns) or concrete-filled rectangular hollow-section columns (RHS columns). The proposed joint configuration uses hammer-heads extracted from the beam profile. To fulfil the resistance requirement taking account of the possible overstrength of the beam, the resistant moment of the joint is decomposed in the contributions of the different components involved. Then, no overstrength factor needs to be considered for the components related to the beam itself and to the hammer-heads. This approach is in full accordance with the basic principles of Eurocode 8 and can decrease much the required resistance of the joints provided some conditions are fulfilled, meaning lower costs. [less ▲]

The Hybrid Finite-Element Mixing-Cell method: a candidate for modelling groundwater flow and transport in karst systems

in Bertrand, C.; Carry, N.; Mudry, J. (Eds.) et al Proc. H2Karst, 9th Conference on Limestone Hydrogeology (2011, September)

Groundwater flow and contaminant transport modelling in karst systems remains a challenge because of the complexity of the geology made of caves, voids, conduits of various sizes and forms and interacting ... [more ▼]

Groundwater flow and contaminant transport modelling in karst systems remains a challenge because of the complexity of the geology made of caves, voids, conduits of various sizes and forms and interacting matrix. Such heterogeneous structures cause complex hydraulic conditions for groundwater flow and transport processes. Despite the progresses in field investigation techniques and experiments, detailed knowledge and characterization of the karst system geometry and connectivity remains inaccessible and pragmatic modelling approaches have to be used. Groundwater models of different complexities have been developed for karst systems, ranging from transfer functions and linear reservoir models to spatially distributed models. Here, a new flexible modelling approach, the Hybrid Finite-Element Mixing-Cell method (HFEMC), has been developed that allows combining in a single model, and in a fully interacting way, different mathematical approaches of various complexities for groundwater modelling in complex environments. This includes linear reservoirs, distributed reservoirs, groundwater flow in variably saturated equivalent porous media, with possibilities to consider by-pass flows along preferential flow paths, internal boundary conditions between the karstic features and the surrounding rock mass matrix background and drainage by surface waters. This method has been implemented in the groundwater flow and solute transport numerical code SUFT3D. The objective of this communication is to present the modelling concepts and to discuss the potentials and advantages of the HFEMC method for modelling groundwater flow in karst systems over existing more classical modelling approaches. The discussion is supported by illustrative “synthetic” examples representative of karst systems and a real modelling application to the case of groundwater rebound and water inrush in a closed underground coal mine which presents a very similar geometrical and hydrological context to a karst, with cavities, drains and interacting rock mass. [less ▲]

Robustness of building frames further to a column loss - Substructure approach with account of dynamic effects

in EUROSTEEL 2011 - 6th European Conference on Steel and Composite Structures - Proceedings (2011, September)

Nowadays, it is a concern to mitigate the risk of progressive collapse of a whole structure further to exceptional events such as explosions, impacts, fire... Different general approaches are proposed in ... [more ▼]

Nowadays, it is a concern to mitigate the risk of progressive collapse of a whole structure further to exceptional events such as explosions, impacts, fire... Different general approaches are proposed in the Eurocodes and some other national design codes to ensure the robustness of structures, although very few practical guidelines are provided. In the present study, the so-called “alternative load path method” is followed and the conventional scenario “loss of a column” is considered. Investigations were conducted at the University of Liège in the last few years regarding the static behaviour of two-dimensional building frames suffering the loss of a column further to an unspecified accidental event. They resulted in the development of simplified analytical methods for the prediction of the structural response assuming a static behaviour. In particular, it was shown that a substructure composed of the double-beam overhanging directly the lost column and its beam-to-column joints is able to reproduce the response of a 2D frame when membrane forces develop in the beams after the formation of the global beam plastic mechanism induced by the column loss. The dynamic behaviour of such a substructure was more recently investigated. As a result, a simplified approach was developed for the prediction of the maximal displacement of the system and subsequently the internal forces developing in the substructure, permitting the definition of ductility and resistance requirements for robustness. In the present paper, the whole analytical procedure is applied to a particular substructure. First, the static response is determined. Then the proposed model is used to predict the dynamic behaviour of the substructure as a function of the load initially supported by the failing column and the duration of its removal. In this paper, analytical approaches developed at the University of Liège are applied to predict the response of the considered substructure and the results are compared to numerical simulations; but the development of these methods and the observed phenomena are not detailed. [less ▲]

Numerical Simulation of Stationary Roll Forming using ALE formalism

in Oñate, E.; Owen, D. R. J.; Peric, D. (Eds.) et al Computational Plasticity XI - Fundamentals and Applications (2011, September)

Robustness of steel and composite building structures

in 7th National conference on steel structures proceedings (2011, September)

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to the Eurocodes and ... [more ▼]

Recent events such as natural catastrophes or terrorism attacks have highlighted the necessity to ensure the structural integrity of buildings under an exceptional event. According to the Eurocodes and some different other national design codes, the structural integrity of civil engineering structures should be ensured through appropriate measures but, in most cases, no precise practical guidelines on how to achieve this goal are provided. At Liège University, the robustness of building frames is investigated with the final objective to propose design requirements to mitigate the risk of progressive collapse considering the conventional scenario “loss of a column” further to an unspecified event. In particular, a complete analytical procedure has been developed for the verification of the robustness of steel or composite plane frames. For sake of simplicity, these first works have been based on the assumption that the dynamic effects linked to the column loss were limited and could therefore be neglected. More recently, complementary works have been carried out with the objective to address the dynamic effects. Besides, the extension of the static procedure to actual 3D frames is under investigation in Liège. The present paper gives a global overview of the ongoing researches in the field of robustness at Liège University and, in particular, the global strategy aiming at deriving design requirements is detailed. [less ▲]

Extension of the Direct strength method to hot-rolled profiles cross-sections

in 6th European Conference on Steel and Composite Structures : Eurosteel 2011, Budapest 30 October - 2 September 2011 (2011, September)

Current metallic structural design codes use the concept of section classification for determining the section capacity of hot-rolled profiles. In this system, there exists a discontinuity between the ... [more ▼]

Current metallic structural design codes use the concept of section classification for determining the section capacity of hot-rolled profiles. In this system, there exists a discontinuity between the classes 2 and 3, while for the class 4, the effective width method (EWM) must be used to account for local buckling phenomenon. In order to overcome the complicate and time consuming EWM for evaluating the strength, the alternative Direct Strength Method (DSM) approach, developed only for cold-formed thin-walled members, has gained importance over the last few years. The DSM is premised on the assumption that the strength can be predicted from the yield strength to the elastic critical load ratio in conjunction with a strength curve. The DSM has been advanced for calculating the strength of compression members over the past decades and in this paper, the extension of DSM to hot-rolled profiles cross-sections is investigated. Firstly, the methods for calculating the cross-section resistance such as EWM, DSM, and the recent Continuous Strength Method (CSM) are reviewed; a short comparison is made and their domains of applicability are commented. Secondly, a numerical model carried out in the frame of this research is described. The model was built in ABAQUS and verified against test results of the “Semi-comp: Plastic member capacity of semi-compact steel sections - a more economic design” project, which was carried out earlier with the objective of improving the utilization of plasticity in rolled and welded sections with medium cross-section slenderness. On the basis of these premises, the final goal of the project is detailed: to derive a new formulation that would cover the whole field of section slenderness (present class 1 to class 4), which can be seen as an extension of the so-called DSM approach. [less ▲]

Development of a scoring system to assess lameness status in dairy cattle farms

in Société Belge Francophone de Buiatrie & Vlaamse vereniging voor Buiatrie (Ed.) Proceeding of the 6th European Congress of Bovine Health Management (2011, September)

Numerical and Experimental Studies of Simple Geometries in Slamming

in International Journal of Offshore and Polar engineering (2011, September)

Optimization of Hull Structures for a 60 meters Mega Yacht

in Proceeding of the 11th International Conference on Fast Sea Transportation (2011, September)

As well known already in earliest phases of a ship project many aspects and choices depend on the structural design which has been defined only at a preliminary level. This trend appears to be similar for ... [more ▼]

As well known already in earliest phases of a ship project many aspects and choices depend on the structural design which has been defined only at a preliminary level. This trend appears to be similar for merchant ships, passenger ships and motor yachts. Only in the final part of the project some shipyards begin to apply optimization processes, more or less sophisticated, in order to refine the structural design in view of reducing the weight and/or the construction cost. The weight in particular has a very important impact on pleasure vessels, both motor and sailing. Structural modifications suggested by such optimization procedures imply a number of second order changes in related items such as plant, outfitting and others. As a consequence the structural optimization could be particularly useful if it can be applied during the first stages of the project, this way avoiding very expensive time losses and changes caused by any structural modifications. In this paper the structural optimization of a 60 meters megayacht is presented, performed by LBR-5 code developed by the University of Liege. This code is an optimization tool specifically designed for structures composed by stiffened plates and stiffened cylindrical shells. The optimal solution is reached through an optimization algorithm based on convex linearization and a dual approach. The LBR-5 software has been successfully utilized to optimize hull structures of a 60 meters megayacht. Differently from large ships, the mega yacht has not a “cylindrical body” in the central part of the hull. So, a new module of the software has been used in order to analyze several sections of the ship and to perform an overall optimization. For this application the optimization analysis has been carried out by different approaches: assuming the weight as the objective function a gain of about 8% has been achieved, while a least cost optimization allowed a reduction of 15%. [less ▲]

High serum transforming growth factor-beta 1 concentration in West Highland white terriers : a key to the breed predisposition in canine idiopathic pulmonary fibrosis

in Proceedings of the 21st ECVIM-CA Congress (2011, September)

Simulation of differentials in four-wheel drive vehicles using multibody dynamics

in Proceedings of the ASME 2011 International Design Engineering Technical Conference & Computers and Information in Engineering Conference IDETC/CIE 2011 (2011, August 31)

The dynamic performance of vehicle drivetrains is significantly influenced by differentials which are subjected to complex phenomena. In this paper, detailed models of TORSEN differentials are presented ... [more ▼]

The dynamic performance of vehicle drivetrains is significantly influenced by differentials which are subjected to complex phenomena. In this paper, detailed models of TORSEN differentials are presented using a flexible multibody simulation approach, based on the nonlinear finite element method. A central and a front TORSEN differential have been studied and the numerical results have been compared with experimental data obtained on test bench. The models are composed of several rigid and flexible bodies mainly constrainted by flexible gear pair joints and contact conditions. The three differentials of a four wheel drive vehicle have been assembled in a full drivetrain in a simplified vehicle model with modeling of driveshafts and tires. These simulations enable to observe the four working modes of the differentials with a good accuracy. [less ▲]

Dynamic simulation of residential buildings with seasonal sorption storage of solar energy - parametric analysis

in ISES solar world congress 2011 - Proceedings (2011, August 28)

This work focuses on the evaluation of the performances of a solar combisystem coupled to seasonal thermochemical storage using SrBr2/H20 as adsorbent/adsorbate couple. The objective is to determine the ... [more ▼]

This work focuses on the evaluation of the performances of a solar combisystem coupled to seasonal thermochemical storage using SrBr2/H20 as adsorbent/adsorbate couple. The objective is to determine the characteristics required for solar system and storage reactor to reach a 100 % solar fraction for a building with a low heating load. The complete system, including the storage reactor, is simulated, using the dynamic simulation software TRNSYS. The influence of some components and parameters of the system is estimated: weather, collectors and storage reactor parameters. [less ▲]

Assessment of wind energy potential in Niamey, Niger

in Proceedings of the 1st International Conference on Energy, Environment and Climate Change (2011, August 26)

Renewable technologies are considered as clean sources of energy and optimal use of these resources minimize environmental impacts, produce minimum secondary wastes and are sustainable based on current ... [more ▼]

Renewable technologies are considered as clean sources of energy and optimal use of these resources minimize environmental impacts, produce minimum secondary wastes and are sustainable based on current and future economic and societal needs. Renewable energy technologies provide an excellent opportunity for mitigation of greenhouse gas emission and reducing global warming through substituting conventional energy sources. In the Sahel of West Africa, dramatically affected by desertification processes and rainfall shortages, wind energy is often viewed as a technology to mitigate deforestation although its development is extremely limited. The purpose of this study is to assess wind power potential in Niamey, Niger, a country where forest areas have declined by 34.5% over the 1990-2005 period. From 3-hourly meteorological data collected at the Niamey-Airport synoptic station over ten years (1998-2007), we evaluate the wind speed characteristics and the wind power potential at a height of 10 meters above ground level at diurnal, monthly, and yearly scales. We find very large differences in wind speed at the diurnal (2.40 – 5.11 m/s), monthly (2.61 – 4.11 m/s) and yearly (3.21 – 3.73 m/s) scales, with a global average wind speed of 3.42 m/s. We conclude that the wind powered energy is not economically feasible in Niamey due to its low wind potential. [less ▲]

Trends in extreme rainfall events in Benin (West Africa), 1960-2000

in Proceedings of the 1st International Conference on Energy, Environment and Climate Change (2011, August 26)

Global dataset of derived indicators has been compiled to clarify whether the frequency and / or the severity of rainfall extremes changed during the 1960 – 2000 period in the Republic of Benin in West ... [more ▼]

Global dataset of derived indicators has been compiled to clarify whether the frequency and / or the severity of rainfall extremes changed during the 1960 – 2000 period in the Republic of Benin in West Africa. This period provides the best spatial coverage of homogenous daily series, which can be used for calculating the proportion of global land area exhibiting a significant change in extreme or severe rainfall. We selected 12 indicators of extreme climatic events that are based on daily totals of precipitation. The six first indicators are the annual total precipitation (RTOT); the annual total of wet days (with daily rainfall >= 1mm, Rd); the simple day intensity index (SDII) calculated as the average rainfall from wet days; the annual maximum rainfall recorded during 1, 5, and 30 days (Rx1d, Rx5d, and Rx30d). The other six indices are based on the 95th and 99th percentiles calculated from the daily rainfall data over the 1961-1990 period, that is the 30-year period required by the World Meteorological Organization (WMO) for the calculation of normals. The 95th percentile defines a very wet day. The 99th percentile corresponds to an extreme rainfall event. Based on these percentiles, three extreme precipitation indices were chosen. Very wet day and extreme rainfall frequency are based on the annual count of days with rainfall >= 95th and 99th percentiles of 1961-1990 (R95p and R99p). Very wet day and extreme rainfall intensity corresponds to the annual total precipitation recorded from days with rainfall >= 95th and 99th percentiles of 1961-1990 (R95pSUM and R99pSUM). Very wet day and extreme rainfall proportion is the percentage of the annual total precipitation recorded from days with rainfall >= 95th and 99th percentiles of 1961-1990 (R95pTOT and R99pTOT) and measures how much of the total rain comes from very wet or extreme events. Only time series which had complete records from 1960 to 2000 were used. A total of 21 stations time series were extracted from national climate archives and collated into the unique dataset described here. National maps showing trends during the 1960-2000 period were produced. Results show that only the annual total precipitation, the annual total of wet days and the annual maximum rainfall recorded during 30 days present a significant decreasing trend while the other nine rainfall indicators appear to remain stable. These results are important findings for Benin since scarce works realized in neighbouring regions of West Africa describe a situation more prone to increases in extreme rainfall (in Nigeria [1]) or the opposite (in Guinea Conakry [2] and in Niger [3]) in a similar context of a clear reduction in the yearly precipitation amount. We call for further research on this topic in West Africa since water management is a major tool for sustainable development and poverty alleviation. [1] M. New, B. Hewitson, D.B. Stephenson, et al., “Evidence of trends in daily climate extremes over southern and West Africa,” J. Geophys. Res., vol. 111, 2006, D14102, doi:10.1029/2005JD006289. [2] E. Aguilar, A. Aziz Barry, M. Brunet, et al., “Changes in temperature and precipitation extremes in western central Africa, Guinea Conakry, and Zimbabwe, 1955–2006,” J. Geophys. Res., vol. 114, 2009, D02115, doi: 10.1029/2008JD011010. [3] P. Ozer, Y.C. Hountondji, O. Laminou Manzo, “Evolution des caractéristiques pluviométriques dans l’est du Niger de 1940 à 2007,” GEO-ECO-TROP, Vol. 33, pp. 11-30, 2009. [less ▲]

Maximum entropy at intermediate anthropogenic dynamics

in Jones, Bruce; Fu, Bojie (Eds.) The 8th World congress of the International Association of Landscape Ecology: Proceedings, Beijing, August 18-23, 2011 (2011, August 20)

Landscape entropy represents heterogeneity within a landscape (Renyi, 1961; Bogaert et al., 2005). Previous researches found increasing values of entropy by studying a limited number of zones increasingly ... [more ▼]

Landscape entropy represents heterogeneity within a landscape (Renyi, 1961; Bogaert et al., 2005). Previous researches found increasing values of entropy by studying a limited number of zones increasingly affected by anthropogenic effect (O’Neill et al., 1988; Bogaert et al., 2005). The present research aims to generalise the relationship between anthropogenic effect and landscape entropy, with a further goal of linking these concepts to overall biodiversity. 16 study zones from classified LANDSAT TM scenes and Africover maps presenting different anthropogenic effect intensities have been used (Djibu et al., 2008; Bamba et al., 2010; Barima et al., 2010; Munyemba, 2010; Vranken et al., 2011). Simpson's H diversity index based on class number has been used for entropy measurement (Renyi, 1961; Pielou, 1975; Shannon and Weaver, 1963). 1-H has been retained to get the relationship between the index and diversity directly proportional. For anthropogenic effect measurement, O’Neill’s U disturbance index, quotient between anthropogenic and natural areas, has been used (O’Neill et al., 1988). Log H has been retained to linearise the exponential relationship between the index and anthropogenic effect. Correlation between those variables has then been analysed. The scatter plot of the 16 study zones shows a Gaussian curve (Fig. 1) presenting maximal landscape entropy at intermediate anthropogenic effect. This distribution has been modelled by a second order polynomial regression with determination coefficient and significance. This phenomenon has been interpreted in terms of spatial transformation processes (Bogaert et al., 2004) and linked to the habitat heterogeneity hypothesis (Tews, 2004), as well as the intermediate disturbance hypothesis (Connell, 1978; Lindenmayer and Brugman, 2005). [less ▲]

Chemical spots and their dynamical evolution on HgMn stars

in The Physics of Sun and Star Spots, Proceedings of the International Astronomical Union, IAU Symposium, Volume 273 (2011, August 01)

Our recent studies of late B-type stars with HgMn peculiarity revealed for the first time the presence of fast dynamical evolution of chemical spots on their surfaces. These observations suggest a ... [more ▼]

Our recent studies of late B-type stars with HgMn peculiarity revealed for the first time the presence of fast dynamical evolution of chemical spots on their surfaces. These observations suggest a hitherto unknown physical process operating in the stars with radiative outer envelopes. Furthermore, we have also discovered existence of magnetic fields on these stars that have up to now been thought to be non-magnetic. Here we will discuss the dynamical spot evolution on HD 11753 and our new results on magnetic fields on AR Aur. [less ▲]

Two Lie Group Formulations for Dynamic Multibody Systems with Large Rotations

in Proceedings of the ASME 2011 International Design Engineering Technical Conferences (2011, August)

This paper studies the formulation of the dynamics of multibody systems with large rotation variables and kinematic constraints as differential-algebraic equations on a matrix Lie group. Those equations ... [more ▼]

This paper studies the formulation of the dynamics of multibody systems with large rotation variables and kinematic constraints as differential-algebraic equations on a matrix Lie group. Those equations can then be solved using a Lie group time integration method proposed in a previous work. The general structure of the equations of motion are derived from Hamilton principle in a general and unifying framework. Then, in the case of rigid body dynamics, two particular formulations are developed and compared from the viewpoint of the structure of the equations of motion, of the accuracy of the numerical solution obtained by time integration, and of the computational cost of the iteration matrix involved in the Newton iterations at each time step. In the first formulation, the equations of motion are described on a Lie group defined as the Cartesian product of the group of translations R^3 (the Euclidean space) and the group of rotations SO(3) (the special group of 3 by 3 proper orthogonal transformations). In the second formulation, the equations of motion are described on the group of Euclidean transformations SE(3) (the group of 4 by 4 homogeneous transformations). Both formulations lead to a second-order accurate numerical solution. For an academic example, we show that the formulation on SE(3) offers the advantage of an almost constant iteration matrix. [less ▲]

Mid-infrared predictions of cheese yield from bovine milk

in Book of Abstracts of the 62nd Annual Meeting of the European Association for Animal Production (2011, August)

Economically, cheese yield (CY) is very important. Todate, empirical or theoretical formulae allow estimating the theoretical CY from milk fat and casein or protein content of milk. It would be ... [more ▼]

Economically, cheese yield (CY) is very important. Todate, empirical or theoretical formulae allow estimating the theoretical CY from milk fat and casein or protein content of milk. It would be interesting to predict CY during milk recording directly without the need to estimate milk components. Through the BlueSel project, 157 milk samples were collected in Wallonia from individual cows and analyzed using a mid-infrared (MIR) MilkoScanFT6000 spectrometer. Individual laboratory cheese yields (ILCY) were determined for each sample and expressed as g of dry coagulum/100 g of milk dry matter. An equation to predict ILCY from MIR was developed using partial least squared regression (Winisi III). A first derivative pre-treatment of spectra was used to correct the baseline drift. To improve the repeatability of the spectral data, a file which contained the spectra of samples analyzed on 5 spectrometers was used during the calibration. During calibration, 23 outliers were detected a nd removed from the calibration set. The ILCY mean of the final calibration set was 63.9% with a SD of 11.2%. The calibration (C) coefficient of determination (R²) was equal to 0.76 with a standard error (SE) of calibration of 5.5%. A full cross-validation (CV) was preformed to assess the robustness. R²cv was 0.72 with a SECV of 6.0%. The similarity between R²c and R²cv as well as between SEC and SECV permits to consider robustness of the developed equation as good. Even if it is planned to improve the equation with additional samples, this first equation will permit to study ILCY in the Walloon dairy cattle. [less ▲]

The way to agritourist development from constraints to opportunities

in Cawley, Mary (Ed.) The Sustainability of Rural Systems: Local and Global Challenges and Opportunities (2011, August)

In the northwest European countryside, diversification is a common option to preserve a viable agricultural business because many farmers have to restructure their activities to face increasing pressures ... [more ▼]

In the northwest European countryside, diversification is a common option to preserve a viable agricultural business because many farmers have to restructure their activities to face increasing pressures. Many choose tourism business as a mean of diversification. To examine the supply aspect of agritourism development, the paper scrutinizes the motivations or choices reasons for farm tourism as a mean of diversification. Actually some main reasons have been underlined in the literature. Even if economic and financial reasons like new incomes and employments, stability towards agricultural market fluctuations or a better use of farm ressources are the first motivations mentioning, more social and external reasons like sharing experiences, success of other farmers, meeting of people, education of public and consummer, personal interest as a hobby are also significant. Choice reasons may change over time, be different according to the own characteristics of the farm, its development and its environment, or depend on gender. This paper uses data’s from interviews conducted in agritourism accomodations in the Walloon Region and in the Grand-Duchy of Luxembourg to explore these motivations. The research is based on a content analysis aiming a graphical representation of the motivations using an adapted actantial model: a multi-scale analysis identifying the adjuvants and constraints of such motivations is used. The first analysis stress that the answer to a market opportunity and the potential new assignement of unused farm buildings are also observed. Moreover it is showned that entrepreneurship and opportunities come as being factors quite as important as a development based on a survival of the farm. [less ▲]

Variations in Landscape Sensitivity towards Wind Energy in Belgium

in Bruce, Jones; Bojie, Fu (Eds.) Proceedings. The 8th IALE World Congress : Landscape Ecology for Sustainable Environment and Culture (2011, August)

Estimation of human orientation in images captured with a range camera

in Advanced Concepts for Intelligent Vision Systems (ACIVS) (2011, August)

Estimating the orientation of the observed person is a crucial task for some application fields like home entertainment, man-machine interaction, or intelligent vehicles. In this paper, we discuss the ... [more ▼]

Estimating the orientation of the observed person is a crucial task for some application fields like home entertainment, man-machine interaction, or intelligent vehicles. In this paper, we discuss the usefulness of conventional cameras for estimating the orientation, present some limitations, and show that 3D information improves the estimation performance. Technically, the orientation estimation is solved in the terms of a regression problem and supervised learning. This approach, combined to a slicing method of the 3D volume, provides mean errors as low as 9.2° or 4.3° depending on the set of considered poses. These results are consistent with those reported in the literature. However, our technique is faster and easier to implement than existing ones. [less ▲]

Analysis of a robot positioning system based on a rotating receiver, beacons, and coded signals

in Proceedings of the European Signal Processing Conference (EUSIPCO) (2011, August)

Positioning is a fundamental issue in mobile robot applications that can be achieved in multiple ways. Among these methods, triangulation with active beacons is widely used, robust, accurate, and flexible ... [more ▼]

Positioning is a fundamental issue in mobile robot applications that can be achieved in multiple ways. Among these methods, triangulation with active beacons is widely used, robust, accurate, and flexible. In this paper, we analyze the performance of an original system, introduced in a one of our previous papers, that comprises a rotating receiver and beacons that send an On-Off Keying modulated infrared signal. The probability density function of the measured angles is established and discussed. In particular, it is shown that the proposed estimator is a non biased estimator of the beacon angular position. We also evaluate the theoretical results by means of both a simulator and measurements. [less ▲]

SOLVING VERY LARGE-SCALE SECURITY-CONSTRAINED OPTIMAL POWER FLOW PROBLEMS BY COMBINING ITERATIVE CONTINGENCY SELECTION AND NETWORK COMPRESSION

in PSCC conference (2011, August)

This paper proposes a practical algorithm for solving very large-scale SCOPF problems, based on the combination of a contingency filtering scheme, used to identify the binding contingencies at the optimum ... [more ▼]

This paper proposes a practical algorithm for solving very large-scale SCOPF problems, based on the combination of a contingency filtering scheme, used to identify the binding contingencies at the optimum, and a network compression method, used to reduce the complexity of the post-contingency models included in the SCOPF formulation. By combining these two complementary simplifications, it is possible to solve SCOPF problems addressing both preventive and corrective controls on continental sized power system models and with a very large number of contingencies. The proposed algorithms are implemented with state-of-the-art solvers and applied on a model of the European transmission system, of about 15000 buses, and with about 11000 contingencies. [less ▲]

Analysis of the past (1970-1999) and future (2046-2065 and 2081-2100) evolutions of precipitation and temperature, in the Province of Binh Thuan, South East Vietnam, based on IPCC models

in Proceedings of the 1st International Conference on Energy, Environment and Climate Change (2011, August)

Natural resource-dependent societies in developing countries are facing increased pressures linked to global climate change. The Province of Binh Thuan, in South East Vietnam, where rainfall is on average ... [more ▼]

Natural resource-dependent societies in developing countries are facing increased pressures linked to global climate change. The Province of Binh Thuan, in South East Vietnam, where rainfall is on average 500 to 700 mm but can drop as low as 350 mm in some years, knows a recent increase of agricultural activities in order to contribute to reduce poverty although the technical efficiency of Binh Thuan is still very low. Within this framework of higher dependency of the local economy on the agricultural sector, there is growing evidence that changes in climate extremes are increasing exposure of currently vulnerable rural populations. In order to assess the future climate of the province of Binh Thuan, only three models able to simulate the current climate in the study area were used out of the 24 selected by the IPCC: CCCMA-T47, INGV and IPSL. The future climate projections (that is 2046-2065 and 2081-2100 compared to historical data 1970-1999) were focused on two targets: [i] assessing changes in climate statistics, and [ii] analysing the beginning and the end of the rainy season. [i] The first analysis indicates an increase of mean temperature of about 1.6°C (over 2046-2065) and 2.5°C (over 2081-2100) and an increase of extreme temperatures and extreme rainfall events. However, no significant changes about the evolution of the annual amount of precipitation were found. [ii] The second analysis indicates that the dry season is likely to be longer in 2046-2065 owing to a delay in the onset of the rainy season (up to 15 days) accompanied by an earlier end of the rainy season (up to 30 days). Although it must be kept in mind that precipitations are the most difficult climate variable to predict, it is likely that increasing water needs to support expending agriculture within the context of climate change in the Province of Binh Thuan will be a challenge. Indeed, extreme rainfall events are likely to increase and unchanged yearly amounts of precipitation should be concentrated in time. [less ▲]

Prediction of cow pregnancy status using conventional and novel mid-infrared predicted milk traits

in Book of Abstracts of the 62nd Annual Meeting of the European Association for Animal Production (2011, August)

The objective of this study was to determine the ability of conventional milk cow characteristics and novel traits predicted by mid infrared (MIR) obtained from milk recording to predict the pregnancy ... [more ▼]

The objective of this study was to determine the ability of conventional milk cow characteristics and novel traits predicted by mid infrared (MIR) obtained from milk recording to predict the pregnancy status once the cow was inseminated. Conventional milk recording, spectral, and reproductive data collected in Luxembourg Hoslteins between 2008 and 2010 were used. Cows were defined as pregnant if they were positively checked and calved between 267 and 295 d later after the last AI or if they had calved between the later intervals when no checks were recorded. Pregnant or not within 3 intervals after last AI (<=35 d, 45-60 d, and 60-90 d) was modeled using logistic regression models firstly as a function of conventional cow milk characteristics and extended to fatty acids as novel traits predicted by MIR in a second step. The lactation curve characteristics for milk, fat, protein, and lactose yields were estimated using modified best prediction method. Test-day fatty acid contents were estimated from collected MIR spectra using an appropriate calibration equation. Two third proportion and one third of the whole data set were randomly selected for calibration and validation models respectively. The relation between the predicted and observed probabilities of cow pregnancy was approximately linear for calibration and validation models. The sensitivity-specificity combination for cow pregnancy increased when fatty acids were added to conventional milk characteristics as inputs to the different models (from 78 to 85% for sensitivity and from 40 to 52% for specificity). Results based on those models showed that it would be possible to help breeders to manage cow fertility using such tool implemented in the milk recording organizations. [less ▲]

On the Parameters of the Perfectly Matched Layer in Discrete Contexts

in Proceedings of the 10th International Conference on Mathematical and Numerical Aspects of Waves (Waves 2011) (2011, July 26)

Perfectly Matched Layer (PML) techniques are widely used for dealing with unbounded problems. However their performance depends critically on both an absorption coefficient and the numerical method. The ... [more ▼]

Perfectly Matched Layer (PML) techniques are widely used for dealing with unbounded problems. However their performance depends critically on both an absorption coefficient and the numerical method. The coefficient is generally tuned by using costly and case-dependent optimization procedures or set empirically. In this paper we present some efficient profiles of the coefficient that allow to avoid any tuning in discrete contexts. These profiles are compared by means of two benchmarks with different numerical methods. [less ▲]

Influence of a static wing wake on the stall flutter behavior of a flexible wing

in Proceedings of the 13th International Conference on Wind Engineering, ICWE13 (2011, July 13)

The subject of this paper is the experimental study of the aeroelastic behavior of a wing undergoing stall flutter in the vicinity of second, static wing. While stall flutter has been the subject of ... [more ▼]

The subject of this paper is the experimental study of the aeroelastic behavior of a wing undergoing stall flutter in the vicinity of second, static wing. While stall flutter has been the subject of several investigations, such work has almost always concentrated on isolated wings. Stall flutter is a phenomenon that is mostly encountered in rotating blades, such as wind turbine or helicopter blades. In such cases, the phenomenon is influenced by the wake of the preceding blade. This paper presents a series of experiments carried out at the Goldstein Laboratory of the University of Manchester, concerning the phenomenon of stall flutter influenced by the proximity of a static wing. The work is an extension of the single wing stall flutter experiments presented by Dimitriadis and Li (2009). [less ▲]

Influence of thermoelectric coupling on pacemaker activity generated by mechano-electric feedback in a one-dimensional ring-shaped model of cardiac fiber

in XXIIIrd congress of the International Society of Biomechanics, July 3-7, 2011 (2011, July 05)

Optimization of flexible components in reciprocating engines with cyclic dynamic loading

in Samin, Jean-Claude; Fisette, Paul (Eds.) Proceedings of Multibody Dynamics 2011, Eccomas Thematic Conference: Brussels (Belgium), 4-7 juillet 2011 (2011, July 05)

This work considers the optimization of flexible components of mechanical systems modeled as multibody systems. This approach permits to better capture the effects of dynamic loading under service ... [more ▼]

This work considers the optimization of flexible components of mechanical systems modeled as multibody systems. This approach permits to better capture the effects of dynamic loading under service conditions. This process is challenging because most state-of-the-art studies in structural optimization have been conducted under static or quasi-static conditions. The formulation of the optimization problem for dynamic systems is fundamental; it is not a simple extension of static optimization. Naive implementation leads to fragile and unstable results. The present paper addresses the optimization of a connecting rod of a reciprocating engine with cyclic dynamic loading. Gradient-based methods are adopted for their convergence speed. Different formulations are investigated and compared. A first numerical application considers the optimization of the connecting rod regarding its mass and its elongation. After, another numerical application is carried on considering the stresses in the connecting rod. A conclusion on the influence of the optimization problem formulation is realized. [less ▲]

Non-thermal radio emission from colliding-wind binaries: modelling Cyg OB2 No. 8A and No. 9

in Neiner, Coralie; Wade, G.; Meynet, G. (Eds.) et al Active OB stars: structure, evolution, mass loss and critical limits (2011, July 01)

Some OB stars show variable non-thermal radio emission. The non-thermal emission is due to synchrotron radiation that is emitted by electrons accelerated to high energies. The electron acceleration occurs ... [more ▼]

Some OB stars show variable non-thermal radio emission. The non-thermal emission is due to synchrotron radiation that is emitted by electrons accelerated to high energies. The electron acceleration occurs at strong shocks created by the collision of radiatively-driven stellar winds in binary systems. Here we present results of our modelling of two colliding wind systems: Cyg OB2 No. 8A and Cyg OB2 No. 9. [less ▲]

The surprising X-ray emission of Oe stars

in Neiner, Coralie; Wade, G.; Meynet, G. (Eds.) et al Active OB stars: structure, evolution, mass loss and critical limits (2011, July 01)

Oe stars are thought to represent an extension of the Be phenomenon to higher temperatures. Dedicated XMM observations of HD 155806 revealed a surprising X-ray spectrum: soft character, absence of ... [more ▼]

Oe stars are thought to represent an extension of the Be phenomenon to higher temperatures. Dedicated XMM observations of HD 155806 revealed a surprising X-ray spectrum: soft character, absence of overluminosity, broad X-ray lines. These properties are fully compatible with the wind-shock model, which usually explains the X-rays from ``normal'', single O-type stars. In contrast, some other Oe/Be stars display a completely different behaviour at high energies. [less ▲]

Variability monitoring of OB stars during the Mons campaign

in Neiner, Coralie; Wade, G.; Meynet, G. (Eds.) et al Active OB stars: structure, evolution, mass loss and critical limits (2011, July 01)

We present preliminary results of a 4-month campaign carried out in the framework of the Mons project, where time-resolved Hα observations are used to study the wind and circumstellar properties of a ... [more ▼]

We present preliminary results of a 4-month campaign carried out in the framework of the Mons project, where time-resolved Hα observations are used to study the wind and circumstellar properties of a number of OB stars. [less ▲]

Overall properties of hot, massive stars in the X-ray domain

(2011, July 01)

Despite the absence of large surveys, the recent X-ray observatories provide X-ray data for hundreds of massive stars (294 OB stars detected in the 2XMM catalog, 129 OB stars detected in the Chandra ... [more ▼]

Despite the absence of large surveys, the recent X-ray observatories provide X-ray data for hundreds of massive stars (294 OB stars detected in the 2XMM catalog, 129 OB stars detected in the Chandra Carina Complex Project). Analyzing medium-resolution spectra led to new results on the relationship between the X-ray luminosity and the bolometric luminosity, as well as on the typical properties (plasma temperature, variability) of these objects. [less ▲]

The mysterious high-latitude O-star HD 93521: new results from XMM-Newton observations

in Neiner, Coralie; Wade, G.; Meynet, G. (Eds.) et al Active OB stars: structure, evolution, mass loss and critical limits (2011, July 01)

The O9.5 Vp star HD 93521 is a well known non-radial pulsator located at a high Galactic latitude. The nature (Population I vs. II) of this star has been the subject of controversy for many years. We ... [more ▼]

The O9.5 Vp star HD 93521 is a well known non-radial pulsator located at a high Galactic latitude. The nature (Population I vs. II) of this star has been the subject of controversy for many years. We report on an XMM-Newton observation of the star that sheds new light on its nature. [less ▲]

Eddy currents and corner singularities

in 18th Conference on the Computation of Electromagnetic Fields (COMPUMAG2011) (2011, July)

The eddy current problem is addressed in this paper, in a bidimensional setting where the conducting medium is non- magnetic and has a corner singularity. For any fixed skin depth we describe the ... [more ▼]

The eddy current problem is addressed in this paper, in a bidimensional setting where the conducting medium is non- magnetic and has a corner singularity. For any fixed skin depth we describe the behaviour of the potential near the corner, which is not singular at the corner, unlike the perfect conducting case. Then as δ goes to zero, the first two terms of a multiscale expansion of the potential are introduced to tackle the magneto-harmonic problem. The heuristics of the method are given and numerical computations illustrate the obtained accuracy. [less ▲]

A short Survey of Methods for Voltage Instability Detection

in Proceedings of the IEEE PES General Meeting (2011, July)

This paper shortly surveys existing and proposed methods for voltage instability detection. The emphasis is on methods relying on real-time measurements as well as on long-term voltage instability ... [more ▼]

This paper shortly surveys existing and proposed methods for voltage instability detection. The emphasis is on methods relying on real-time measurements as well as on long-term voltage instability. Methods are classified according to the required measurement configuration: local vs. wide-area, standard SCADA-type vs. synchronized phasor measurements, etc. In the various categories, some of the features are summarized, and what appears to the authors as advantages or limitations is shortly discussed. An important feature is the ability to anticipate instability. Some tracks for further work on the subject are also outlined. [less ▲]

Development of an urban typology to assess residential environmental performance at the city scale

in Evrard Arnaud, Bodard Magali (Ed.) Proceedings of International Conference PLEA 2011 : Architecture & Sustainable Development (2011, July)

In this research, a typology of urban blocks is drawn up for the urban area of Liege. This typology of urban blocks is organized into a set of themes according to various environmental parameters. This ... [more ▼]

In this research, a typology of urban blocks is drawn up for the urban area of Liege. This typology of urban blocks is organized into a set of themes according to various environmental parameters. This paper presents the energy part of this typology on the residential building stock of Liege, which includes four topics: residential buildings energy consumption; transport energy consumption of residents; development potentialities of public transport and development potentialities of energy networks. The proposed typology was elaborated through the use of GIS tools combined with a statistical treatment of several specific criteria at the urban block scale. For each class of this typology, a representative block is selected for further energy simulations in order to model residential energy use related to buildings, transport and energy networks at the city scale. The methodology developed in this paper is adapted to urban, suburban and rural zones. It can thus be adapted and/or reproduced on many other territories in Belgium but also in Europe or even further. [less ▲]