Wear characteristics of porcelain denture teeth

Surface wear and frictional behavior of porcelain denture teeth were examined with a single-pass sliding technique. The influence of environment, type of surface (enamel or dentin) and repeated passes on the wear characteristics of the teeth were investigated. The enamel surface of the teeth was more resistant to penetration and to surface damage than the dentin surface was. Damage was more severe for double-pass than for single-pass sliding. The wear characteristics were affected similarly by the liquid environments of water and of human saliva. Quantitative differences in the wear parameters investigated were found between the two brands of porcelain denture teeth.     

Converging coolness and investigating its relation to user experience

Recently a number of studies appeared that operationalised coolness and explored its relation to digital products. Literature suggests that perceived coolness is another factor of user experience, and this adds to an existing explosion of dimensions related to aesthetics, hedonic quality, pragmatic quality, attractiveness, etc. A critical challenge highlighted in prior research is to study the relationships among those factors and so far, no studies have empirically examined the relationship between coolness and other established user experience factors. In this paper, we address this challenge by presenting two studies one that focuses on factors from two cool questionnaires, and one that compares them against existing User eXperience (UX) factors. Our findings show that factors from the two cool questionnaires converge and they also converge to existing, established UX factors. Thus, 11 distinct cool and UX factors converge into 5 for the case of mobile devices. Our findings are important for researchers, as we demonstrate through a validated model that coolness is part of UX research, as well as for practitioners, by developing a questionnaire that can reliably measure both perceived inner and outer coolness as well as the overall coolness judgement based on 5 factors and 21 items.     

Effects of a porous medium on the accelerated flow past a vertical porous surface

In the present work we investigate the effects of a porous medium on the accelerated flow past a vertical porous limiting surface. The solution of the problem is obtained in closed form by using the Laplace transform technique.     

Vapor sorption in thin supported polymer films studied by white light interferometry

In the present study, we apply a white light interferometric methodology to study sorption of moisture and methanol vapor in thin films of poly(2-hydroxyethyl methacrylate) [PHEMA] and poly(methyl methacrylate) [PMMA], supported on oxidized silicon wafers. The measured equilibrium thickness expansion of each film, exposed to different activities of the vapor penetrant, is used to determine the sorption isotherm of the system. Results for relatively thick films (100 nm < L_o < 600 nm) are compared with corresponding literature data for bulk, free-standing films, obtained by direct gravimetric methods. Furthermore, PMMA films of thicknesses lower than 100 nm were employed in order to study the effect of the dry film's thickness, and of substrate, on fractional swelling.     

Evaluation of sensor materials for ultrasonic thermometry In coal gasification systems

The success of ultrasonic thermometry, in coal gasification systems depends on the selection of approprzate sensor materzal(s) that can withstand the hostile environment exhibit good. acoustic sen~itivity to temperature and show long-term stability or reproducibility of acoustic properties in the environment. Six candidate materials SS 310, Incoloy 800, sapphire, alumina, spinel and chrome oxide - were selected based on pilot-plant. experience and laboratory studies of materials performance in coal galasification environments. They were exposed in two simulated coal gasification environment, Westinghouse low-Btu (British thermal unit) at 871°C for 15 hand Texaco medium-Btu at 982°C for 15 h. The physical and acoustic properties of the materzals before and after exposure to the gasification environments are presented, together With a discussion on the long-term performance predictions of the materials for ultrasonic thermometry.     

Detailed resist film modeling in stochastic lithography simulation for line-edge roughness quantification

Modeling the lithography process with stochastic principles enables the consideration of resist material and process effects variability on critical dimensions and line-edge or line-width roughness of printed features. These principles are applied for a resist system where polymer and photo-acid-generator (PAG) are blended, and for the same system with the PAG molecules bonded on the main polymer chain. Three-dimensional chain-like models of resist and PAG are considered and examples of their effect on critical dimensions and on resist edge roughness are presented. Comparison with experimental results from the literature proves the validity of the current approach and suggests that it can be used for the prediction of the resist resolution and low roughness capabilities.     

Optimized compressive sampling for passive millimeter-wave imaging

In this paper, we briefly describe a single detector passive millimeter-wave imaging system, which has been previously presented. The system uses a cyclic sensing matrix to acquire incoherent measurements of the observed scene and then reconstructs the image using a Bayesian approach. The cyclic nature of the sensing matrix allows for the design of a single unified and compact mask that provides all the required random masks in a convenient way, such that no mechanical mask exchange is needed. Based on this setup, we primarily propose the optimal adaptive selection of sampling submasks out of the full cyclic mask to obtain improved reconstruction results. The reconstructed images show the feasibility of the imaging system as well as its improved performance through the proposed sampling scheme.     

Packet Delay Metrics for IEEE 802.11 Distributed Coordination Function

In this paper, we introduce a comprehensive packet delay analysis for wireless networks based on IEEE 802.11 Distributed Coordination Function (DCF). We develop mathematical models that calculate a set of packet delay metrics, namely a) the average packet delay for successfully transmitted packets, b) the average packet delay of successfully transmitted packets experiencing a specific number of collisions, c) the average packet drop time, d) the delay jitter and e) the delay distribution by computing the probability of a packet to be successfully transmitted experiencing delay time lower than a given value. All the developed models are based on calculating station’s delay time at the transmission slot(s) plus the average time that station defers at backoff slots before successful transmission. The mathematical models are simple, computationally fast and can be used to build admission control algorithms. Simulation results show that our proposed mathematical analysis is highly accurate.