Micromachined two dimensional resistor arrays for determination of gas parameters

A resistive sensor array is presented for two dimensional temperature distribution measurements in a micromachined flow channel. This allows simultaneous measurement of flow velocity and fluid parameters, like thermal conductivity, diffusion coefficient and viscosity. More general advantages of measuring temperature distributions are the inherent compensation of heat losses to the support and the insensitivity to variations in the temperature coefficient of resistance

Highly sensitive micro coriolis mass flow sensor

We have realized a micromachined micro Coriolis mass flow sensor consisting of a silicon nitride resonant tube of 40 ?m diameter and 1.2 μm wall thickness. Actuation of the sensor in resonance mode is achieved by Lorentz forces. First measurements with both gas and liquid flow have demonstrated a resolution in the order of 10 milligram per hour. The sensor can simultaneously be used as a density sensor

MEMS based hair flow-sensors as model systems for acoustic perception studies

Arrays of MEMS fabricated flow sensors inspired by the acoustic flow-sensitive hairs found on the cerci of crickets, have been designed, fabricated and characterized. The hairs consist of up to 1 mm long SU-8 structures mounted on suspended membranes with normal translational and rotational degrees of freedom. Electrodes on the membrane and on the substrate form variable capacitors allowing for capacitive read-out. Capacitance versus voltage, frequency dependency and directional sensitivity measurements have been successfully carried out on fabricated sensor arrays, showing the viability of the concept. The sensors form a model-system allowing for investigations on sensory acoustics by their arrayed nature, their adaptivity via electrostatic interaction (frequency tuning and parametric amplifica- tion) and their susceptibility to noise (stochastic resonance

Концепція сталого розвитку туризму в сучасних умовах

Мета статті – розробка основних положень концепції сталого розвитку туризму в регіоні

Relaties tussen acidose in de pens, in de darm en in het metabolisme van melkvee tijdens de vroege lactatie : deskstudie

Uit deze deskstudie blijkt dat de energetische kosten die gemoeid zijn met het reguleren van het zuur-base evenwicht in de melkkoe en het corrigeren van een verzuring (acidose) naar verwachting een aanzienlijk deel uitmaken van de energetische onderhoudsbehoefte van vitale organen en de gehele koe. Dit betekent dat acidose op pensniveau, dikke darmniveau of op het niveau van het metabolisme van de koe een belangrijke invloed kan hebben op het functioneren van de melkkoe. Er is nauwelijks experimenteel onderzoek beschikbaar rondom de mogelijk negatieve invloed van acidose (met name in de dikke darm en metabool) op het functioneren van de melkkoe tijdens de vroege lactatie. Er zijn aanwijzingen voor een dergelijke negatieve uitwerking en voor de interactie tussen het optreden van acidose, de metabole status van de melkkoe en de gezondheidsproblemen die dikwijls in deze periode optreden. Mogelijke interacties tussen acidose op het niveau van de pens, de dikke darm en het metabolisme worden bediscussieerd. Invloedfactoren bij een pensacidose, een dikke darmacidose en een metabole acidose worden opgesomd. Een overzicht wordt gegeven van de kenmerken van de fysiologische status van een melkkoe tijdens de vroege lactatie, van de metabole fenomenen die samengaan met het optreden van een acidose op een van de drie niveaus, en van de directe oorzakelijke factoren en processen die betrokken zijn bij het ontstaan van een acidose.---This review indicates that the energetic costs associated with the regulation of acid-base equilibrium in the dairy cow and the required adjustments with acidification (acidosis) are expected to be a considerable portion of the energy requirement of vital organs and the whole cow. This implies that acidosis at the rumen level, at the large intestinal level or at the metabolic level may have a significant impact on cow performance. Experimental research around the potentially negative effects of acidosis (particularly in the large intestine and metabolically) on cow functioning during early lactation is lacking however. There are indications for such negative effects and for the interaction between the occurrence of acidosis, the metabolic state of the dairy cow and impaired health which often occurs during this stage of lactation. Possible interactions between acidosis at the rumen, the large intestinal and the metabolic level are discussed. Influencing factors for acidosis in the rumen, the large intestine and metabolically are listed. An overview is given of features of the physiological state of a lactating cow during early lactation, of the metabolic phenomena that go together with the occurrence of acidosis at one of the three levels, and of the direct causal factors and processes involved with the development of such acidosis

Ambient temperature-gradient compensated low-drift thermopile flow sensor

A highly-sensitive thermal flow sensor for liquid flow with nl-min-1 resolution has been realised. The sensor consists of freely-suspended silicon-rich silicon-nitride microchannels with integrated Al heater resistors and Al/poly-Si++ thermopiles. The influence of drift in the thin-film metal resistors is effectively eliminated by using thermopiles combined with an adequate measurement method, where the power in the heater resistors is controlled, e.g. constant-power calorimetric method or temperature balancing method. The special meandering layout of the microchannels and the placement of thermopile junctions increases sensitivity by summing the thermopile voltages due to convection by fluid flow, whereas the influence of ambient temperature gradients is compensated for

Child Well-Being in Rich Countries: UNICEF’s Ranking Revisited, and New Symmetric Aggregating Operators Exemplified

In a report published in 2007 UNICEF measured six dimensions of child well-being for the majority of the economically advanced nations. No overall scores are given, but countries are listed in the order of their average rank on the dimensions, which are therefore implicitly assigned ‘equal importance’. In this study we take ‘equal importance’ to mean that the final aggregation is symmetrical in the scores and the ranks, i.e. permuting them leaves the aggregate unchanged. We rank the countries by aggregating the numerical information using a variety of techniques, geared to the measurement scales we distinguish (‘ordinal’, ‘interval’, ‘ratio’). The aggregators are symmetrical and mildly demanding, emphasizing good performance across the board. The rankings obtained deviate from the UNICEF ranking, but not over-dramatically. Our purpose is not only to study alternative approaches for the particular data at hand, but also to introduce and exemplify new and useful aggregation techniques: we propose ways to select weights for OWA-operators and weighted geometric means, and we suggest how to circumvent the choice of a power for the power means. In addition we extend the Borda method so that it values dominance as well