Mass and density estimates contribute to perceived heaviness with weights that depend on the densities’ reliability

0.96). Density information contributed for 14%, 21% and 29% to heaviness, when vision was strongly impaired, mildly impaired or not impaired, respectively. Overall, the results highly corroborate our model, which appears to be promising as unifying framework for a number of findings on the size-weight illusion

Energy resolving power of transition-edge X-ray microcalorimeters

This thesis describes the development and device physics of an X-ray microcalorimeter. This is a device for measuring the energy of X-rays. The microcalorimeter measures the temperature increase that is the result of the absorption of an X-ray photon. Combined into an array, the microcalorimeter can be used as an imaging spectrometer. The availability of an imaging X-ray spectrometer with a high energy resolving power will have a significant impact in astronomy and material analysis. In astronomy, X-ray spectra provide information about high-energy processes taking place in the universe. In material analysis, the structure and composition of materials can be determined. The work described here is guided by therequirements of an instrument for XEUS, a future space-based astrophysical observatory. The microcalorimeter is based on a superconducting-to-normal phase transition edge thermometer (TES). This is a superconductor that is voltage-biased in the very narrow transition from superconducting to resistive behaviour. In the transition, the electrical resistance is very sensitive to changes in the temperature, making the TES a good temperature to resistance transducer. The resistive element is easily incorporated in an electrical read-out circuit. The energy resolving power of the microcalorimeter is limited by noise. In this thesis, this noise is studied in detail, both in experimental sensors as well as through simulations. The sensors are fabricated using existing Si3N4 micromachining and thin-film photolithographical techniques. Several sensors with small square absorbers were manufactured and tested. With an operating temperature of 0.1 K, their energy resolution was about 4.5 eV for X-ray photons of 5.9 keV. This is equivalent to a resolving power of 1300. This energy resolution is satisfactory, but not as good as predicted by theory. This discrepancy was investigated and forms the heart of this thesis. The difference between theory and measurement was explained by a combination of two effects: Firstly, because the TES and absorber are seperate parts in the sensor, there can be an exchange of energy between the two. This results in an internal noise component which deteriorates the energy resolution. By changing the sensor geometry, we were able to influence and reduce the spectral density of this noise component. Using a numerical noise simulation, several geometries were evaluated. Secondly, the predicted resolution is based on a small-signal model, which assumes limited excursions over the transition of the TES. For actual X-ray pulses that use a significant part of the dynamic range of the TES, this model was found to be incorrect. The large excursions cause the pulse shape to deviate from the ideal shape as assumed by the small-signal model. Because of this, the small-signal model predicts a better resolution than could actually be measured. Using measured pulse shapes, a more accurate prediction was made, which is in agreement with the measurements. A simple large-signal model was constructed to simulate pulse shapes based on the sensor parameters. With this model, the energy resolution can be described as a function of the size of the excursion over the transition (equivalent to different X-ray photon energy or device heat capacity). The model can be used for performance prediction at arbitrary X-ray energies and for improved sensor optimisation

Identifying Haptic Exploratory Procedures by Analyzing Hand Dynamics and Contact Force

Haptic exploratory procedures (EPs) are prototypical hand movements that are linked to the acquisition of specific object properties. In studies of haptic perception, hand movements are often classified into these EPs. Here, we aim to investigate several EPs in a quantitative manner to understand how hand dynamics and contact forces differ between them. These dissimilarities are then used to construct an EP identification model capable of discriminating between EPs based on the index finger position and contact force. The extent to which the instructed EPs were distinct, repeatable, and similar across subjects was confirmed by showing that more than 95 percent of the analyzed trials were classified correctly. Finally, the method is employed to investigate haptic exploratory behavior during similarity judgments based on several object properties. It seems that discrimination based on material properties (hardness, roughness, and temperature) yields more consistent classification results compared to discrimination based on the acquisition of shape information. © 2013 IEEE

Haptic Discrimination and Matching of Viscosity

In three experiments, viscosity perception of liquids using the sense of touch was studied. The first two were discrimination experiments in which Weber fractions were determined for a number of viscosities spanning the range of what is encountered in daily life, and for two ways of perceiving viscosity (stirring with a spatula or with the index finger). For high viscosities, Weber fractions were around 0.3, whereas they increased for lower viscosities. For low viscosities, discrimination performance was much worse with the finger than with the spatula. In the third experiment, subjects matched liquids perceived with these two methods, which resulted in biases of around 80 %. Control experiments and force measurements were performed to find an explanation for these results. It was concluded that the relationship between perceived and physical viscosity is steeper for stirring liquids with a spatula than stirring with the finger

Діяльність органів військової цензури 1914–1917 рр.: історико-правові аспекти

У статті на основі широкого архівного матеріалу проаналізовано законодавство, яке регламентувало функціонування органів військової цензури в Російській імперії протягом 1914–1917рр.In the article on base of the broad archive material legislation, providing operation of military censorship organ in Russian empire during 1914–1917 is analysed

Fotografia B088

In this paper, studies into the tactual perception of two liquid material properties, viscosity and wetness, are reviewed. These properties are very relevant in the context of interaction with liquids, both real, such as cosmetics or food products, and simulated, as in virtual reality or teleoperation. Both properties have been the subject of psychophysical characterisation in terms of magnitude estimation experiments and discrimination experiments, which are discussed. For viscosity, both oral and manual perception is discussed, as well as the perception of the viscosity of a mechanical system. For wetness, the relevant cues are identified and factors affecting perception are discussed. Finally, some conclusions are drawn pertaining to both properties

De huid als waarneemorgaan

In de huid bevinden zich verschillende soorten (mechano- en thermo)receptoren die belangrijk zijn voor waarneming middels de tast. In dit artikel zal eerst een kort overzicht van deze receptoren worden gegeven. Daarna volgen er voorbeelden van onderzoeken naar de grenzen van de menselijke tastwaarneming waarbij de huid een relatief belangrijke rol speelt. Tenslotte zullen er een paar voorbeelden worden gegeven van toepassingen van dit onderzoek

Kinaesthetic and cutaneous contributions to the perception of compressibility

Compressibility or hardness of objects is an important aspect in haptic perception. Both cutaneous and kinaesthetic information are used for the perception of compressibility. In this paper, the relative role of these contributions is investigated. This is done with psychophysical experiments using a purpose-made silicon rubber stimulus set. The fabrication and characterisation of the stimuli are described, as well as discrimination experiments with and without surface deformation of the stimuli. With the cutaneous cues of surface deformation present, the Weber fraction for hardness discrimination was 0.12. When surface deformation was removed and only kinaesthetic cues were available, the Weber fraction doubled, suggesting that the cutaneous sense contributes almost three quarters to hardness perception, and the kinaesthetic just over one quarter, if the information is integrated in a statistically optimal fashion