26 research outputs found

    Back to reality: How domestic energy efficiency policies in four European countries can be improved by using empirical data instead of normative calculation.

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    It is now well established that there is a serious gap between normative Energy Performance Certificate (EPC) calculations and measured energy consumption in the domestic sector. The fact that there are similarities in this gap between different European countries with varied housing stocks, different normative (EPC) dwelling consumption calculation methods and different cultural norms is surprising. This gap affects the analysis of current energy consumption and the estimation of future energy saving and its cost-effectiveness. This paper presents the results of comparing the differences between measured consumption and normative estimations of residential energy consumptions using national standard (EPC) calculations in four European countries (United Kingdom, France, The Netherlands and Germany). The potential causes of this gap are discussed in terms of behavioural change, technological performance and the application of normative models. Normative calculations are currently used to help develop both European and national energy efficiency policies. In the recast of the EPBD directive for example, cost-optimality calculations for major renovations and Nearly-Zero-Energy Buildings are based on normative standards. The paper provides examples of the potential impact that using normative as opposed to calculations grounded in empirical data may have on policy decisions

    Active vibration isolation system for CLIC final focus

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    International audienceWith pinpoint accuracy, the next generation of Linear Collider such as CLIC will collide electron and positron beams at a centre of mass energy of 3 TeV with a desired peak luminosity of 2*1034 cm-2s-1. One of the many challenging features of CLIC is its ability to collide beams at the sub-nanometer scale at the Interaction Point (IP). Such a high level of accuracy could only be achieved by integrating Active Vibration Isolation systems (AVI) upstream of the collision to prevent the main source of vibration: Ground Motion (GM). Complementary control systems downstream of the collision (Interaction Point FeedBack (IPFB), Orbit FeedBack (OFB)) allow low frequency vibration rejection. This paper focuses on a dedicated AVI table designed for the last focusing quadrupole (QD0) where the specifications are the most stringent. Combining FeedForward (FF) and FeedBack (FB) techniques, the prototype is able to reduce GM down to 0.6 nm RMS(4Hz) experimentally without any load. These performances couldn't be achieved without cutting edge-technology such as sub-nanometer piezo actuators, ultra-low noise accelerometers and seismometers and an accurate guidance system. The whole AVI system is described in details. Further developments concern the integration of the final focusing magnet above the AVI table, first as part of the simulation with its dynamical model, and finally, as a realistic prototype

    Sub-nanometer active seismic isolator control

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    Ambitious projects such as the design of the future Compact Linear Collider (CLIC) require challenging parameters and technologies. Stabilization of the CLIC particle beam is one of these challenges. Ground motion (GM) is the main source of beam misalignment. Beam dynamics controls are however efficient only at low frequency (<4Hz), due to the sampling of the beam at 50 Hz. Hence, ground motion mitigation techniques such as active stabilization are required. This paper shows a dedicated prototype able to manage vibration at a sub-nanometer scale. The use of cutting edge sensor technology is however very challenging for control applications as they are usually used for measurement purposes. Limiting factors such as sensor dynamics and noise lead to a performance optimization problem. The current state of the art in GM measurement and GM mitigation techniques is pointed out and shows limits of the technologies. The proposed active device is then described and a realistic model of the process has been established. A dedicated controller design combining feedforward and feedback techniques is presented and theoretical results in terms of Power Spectral Density (PSD) of displacement are compared to real time experimental results obtained with a rapid control prototyping tool

    Stabilization of weak ferromagnetism by strong magnetic response to epitaxial strain in multiferroic BiFeO3

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    Multiferroic BiFeO3 exhibits excellent magnetoelectric coupling critical for magnetic information processing with minimal power consumption. However, the degenerate nature of the easy spin axis in the (111) plane presents roadblocks for real world applications. Here, we explore the stabilization and switchability of the weak ferromagnetic moments under applied epitaxial strain using a combination of first-principles calculations and group-theoretic analyses. We demonstrate that the antiferromagnetic moment vector can be stabilized along unique crystallographic directions ([110] and [-110]) under compressive and tensile strains. A direct coupling between the anisotropic antiferrodistortive rotations and the Dzyaloshinskii-Moria interactions drives the stabilization of the weak ferromagnetism. Furthermore, energetically competing C- and G-type magnetic orderings are observed at high compressive strains, suggesting that it may be possible to switch the weak ferromagnetism &quot;on&quot; and &quot;off&quot; under the application of strain. These findings emphasize the importance of strain and antiferrodistortive rotations as routes to enhancing induced weak ferromagnetism in multiferroic oxides.ope

    Primerjava toksičnosti etanola in acetaldehida za podganje astrocite v primarni kulturi

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    This study compared the effects of toxicity of ethanol and its first metabolite acetaldehyde in rat astrocytes through cell viability and cell proliferation. The cells were treated with different concentrations of ethanol in the presence or absence of a catalase inhibitor 2-amino-1,2,4 triazole (AMT) or with different concentrations of acetaldehyde. Cell viability was assessed using the trypan blue test. Cell proliferation was assessed after 24 hours and after seven days of exposure to either ethanol or acetaldehyde. We showed that both ethanol and acetaldehyde decreased cell viability in a dose-dependent manner. In proliferation studies, after seven days of exposure to either ethanol or acetaldehyde, we observed a significant dose-dependent decrease in cell number. The protein content study showed biphasic dose-response curves, after 24 hours and seven days of exposure to either ethanol or acetaldehyde. Co-incubation in the presence of AMT significantly reduced the inhibitory effect of ethanol on cell proliferation. We concluded that long-term exposure of astrocytes to ethanol is more toxic than acute exposure. Acetaldehyde is a much more potent toxin than ethanol, and at least a part of ethanol toxicity is due to ethanol’s first metabolite acetaldehyde.V študiji smo primerjali toksičnost etanola in njegovega prvega metabolita acetaldehida za podganje astrocite z določitvijo celične viabilnosti in proliferacije. Celične kulture smo tretirali z različnimi koncentracijami etanola, etanola v prisotnosti inhibitorja katalaze 2-amino-1,2,4 triazol-a (AMT) ali z različnimi koncentracijami acetaldehida. Celično viabilnost smo vrednotili s pomočjo testa s tripanskim modrilom, celično proliferacijo pa s štetjem celic in določitvijo koncentracije proteinov po 24-urni, kot tudi 7-dnevni izpostavljenosti. S študijo smo pokazali, da tako etanol kot tudi acetaldehid v odvisnosti od njune koncentracije zmanjšata celično viabilnost. V študiji proliferacije sta etanol in acetaldehid, v odvisnosti od njunih koncentracij, značilno zmanjšala število celic po 7-dnevni izpostavljenosti. Pri ugotavljanju vsebnosti proteinov smo dobili bifazno krivuljo tako po 24-urni, kot tudi po 7-dnevni izpostavljenosti različnim koncentracijam etanola oziroma acetaldehida. Prisotnost AMT je signifi kantno zmanjšala učinek etanola na celično proliferacijo. Zaključimo lahko, da je dolgotrajna izpostavljenost astrocitov etanolu bolj toksična kot akutna. Acetaldehid je močnejši toksin kot etanol in vsaj del toksičnosti etanola je posledica delovanja njegovega prvega metabolita, acetaldehida

    Validation française du Big Five Inventory à 10 items (BFI-10)

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    International audienceObjectiveOur primary objective was to validate the French version of the BFI-10, an ultra-short ten-item version of the Big Five Inventory (BFI; John et al., 1991), which allows for a reasonably accurate assessment of personality in circumstances in which more in-depth assessment is not possible. In order to reach a thorough evaluation of the external validity, we also aimed to examine the bandwidth of the BFI-10 scales with reference to the study by De Young, Quilty and Peterson (2007) who distinguished between two aspects in each of the Big Five: Assertiveness and Enthusiasm for Extraversion; Compassion and Politeness for Agreeability; Orderliness and Productiveness for Conscientiousness; Withdrawal and Volatility for Negative Emotionality, and finally Openness to Aesthetics and Openness to Ideas for Open-Mindedness. Our concern with regard to bandwidth was to examine whether the BFI-10 scales have strong enough correlations with both aspects of each domain.MethodsParticipants. Data from four samples were analysed: Sample 1 comprised 2499 undergraduate students (1654 women) who completed the full BFI in university classes; Sample 2 comprised 13,306 participants (8471 women) who filled out the BFI-10 ten items online via Internet; Sample 3 comprised 143 undergraduate students (115 women) who completed the full BFI twice with a two-week interval; Sample 4 comprised 360 undergraduate students (183 women) who filled out the BFI and NEO PI-R. Instruments. The French version of the Big Five Inventory is a 45-item inventory, which measures the five broader domains of personality. The ultrashort Ten-item Big Five Inventory (BFI-10) was developed simultaneously in German and English by Rammstedt and John (2007); it comprises five two-item scales measuring the big five domains. The Neuroticism-Extraversion-Openness Personality Inventory Revised (NEO PI-R; Costa et McCrae, 1992) is a 240-item questionnaire which assesses the big five domains and 30 lower-order facets, i.e. six facets per domain. Statistical analyses. Factor structure and reliability of the five two-item scales were first investigated on samples 1 and 3. Confirmatory factor analyses (CFAs) were conducted on samples 1 and 2, and discriminant validity was assessed via comparison with the NEO PI-R (sample 4). In order to examine the bandwidth of the BFI-10 two-item scales, we studied their correlation not only with the NEO PI-R domains but also with the 30 facets.ResultsThe CFAs showed the good fit of the five-factor structure, with RMSEA = .077 (.072), CFI = .974 (.956), and SRMR = .029 (.027) in samples 1 and 2 respectively. Multigroup CFA conducted in groups 1 and 2 showed invariance across gender of factor loadings and item intercepts. Test-retest reliability was satisfactory with rs ranging from .68 (Open-Mindedness) to .86 (Extraversion and Negative Emotionality). The comparison of the two-item scales with the NEO PI-R scales showed high correlations not only with the NEO domain scales, but also with several facets: Four BFI-10 two-item scales (Extraversion, Conscientiousness, Negative Emotionality, and Open-Mindedness) were highly correlated with at least three of the six NEO facet scales in each domain. For Agreeableness, the magnitude of correlations was smaller, but the pattern of correlations was the same. All BFI-10 scales had at least moderate correlations with both aspects of each domain, with the exception of Negative Emotionality, which measured the NEO Withdrawal aspect better than Volatility.ConclusionThe French version of the BFI-10 demonstrated the expected five-factor structure, satisfactory reliability, and broad bandwidth. It could be a valuable tool for the assessment of personality in circumstances in which it is not possible to use a longer and more in-depth instrument, especially when personality is not the main focus of research but one of the variables to be controlled.L’objectif de cette étude est de valider une adaptation française de la forme très courte du Big Five Inventory (BFI) qui comporte 10 items (BFI-10). Notre but était d’examiner en profondeur, en plus de la structure factorielle et de la fiabilité, la validité de cet instrument, afin de déterminer s’il mesure de manière adéquate les domaines de la personnalité ou seulement certains de leurs aspects. Nous avons recruté 4 échantillons différents (respectivement n = 2499, 13 306, 143 et 360 participants) pour étudier la structure factorielle, la fidélité test-retest et la validité externe du BFI-10. Les instruments utilisés étaient le BFI (échantillons 1, 3 et 4), le BFI-10 (échantillon 2) et le NEO PI-R (échantillon 4). Nous avons étudié la structure factorielle du BFI-10, la fidélité test-retest et la validité externe avec les échelles du NEO PI-R. Les analyses factorielles confirmatoires ont confirmé la pertinence de la structure en cinq facteurs, avec des indices d’ajustement satisfaisants, ainsi que l’invariance selon le sexe des coefficients de saturation et des intercepts, ce qui rend valide la comparaison des scores des femmes et des hommes. La comparaison avec le NEO PI-R montre que les échelles du BFI-10 fournissent une estimation suffisamment large des domaines. Les femmes ont des scores de Névrosisme plus élevés que les hommes (d = 0,55), alors que les différences aux autres échelles sont négligeables. Le BFI-10 présente des qualités psychométriques intéressantes qui permettent une évaluation raisonnablement fiable et valide de la personnalité dans des circonstances où l’emploi d’instruments plus longs n’est pas envisageable
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