Analysis of jaw movements and masticatory muscle activity

This paper describes software developed to analyze the temporal and spatial aspects of jaw movements, the speed, direction and magnitude of these movements in three dimensions, and the associated electromyograms (EMGs) of the masticatory muscles. Data from a subject chewing gum illustrates the software application. Manipulations of the stored digitized data are described. Temporal aspects of each chewing cycle are defined by specified delimiters for the beginning and ending of jaw opening and closing; spatial aspects are quantified by measurements derived from movement trajectories; and peak and mean velocities are derived from the velocity profiles. EMGs are digitized, rectified, averaged and referenced to jaw movement. Onset latencies, burst durations, rise times to peak activity, time of occurrence of peak activity, and amplitudes of peak and mean activities are measured from the EMGs. This detailed kinematic/EMG analysis provides previously inaccessible information about jaw muscles and the movements they control.     

Design of Filters to Reduce Harmonic Distortion in Industrial Power Systems

Shunt filters are effective in minimizing voltage distortion caused by nonlinear loads in industrial power systems. Different alternatives of filter design should be considered before making the final decision on filter configuration. Among the criteria used for performance evaluation are losses, current, and voltage ratings of each of the filter components, and the effect of filter and system contingency conditions. The design and performance of single-tuned and high-pass filters and the methodology used for the analysis will be discussed.     

Kinematics and Wear of Tool Blades for Scrap Tire Shredding

The wear of tool blades for cost-effective scrap tire shredding is investigated. Rotary disk cutters are widely used for cutting scrap tires into small pieces. The hard, wear-resistant tool blades mounted on the periphery of disk cutters maintain a narrow gap between blades and generate the cutting action. The kinematics of the relative motion of two adjacent disk cutters is derived to model the overlap region on blades during cutting. The model predictions match well with the actual shapes of the worn regions on used tool blades. The wear of tool blades made of AISI D2 and CRU-WEAR (CW) tool steels for scrap tire shredding is evaluated. A coordinate measurement machine was used to measure the tool wear. The wear on the blade surface is not uniform. Regions with high wear rate are explained using the kinematics analysis. The CW blades show a lower wear rate, about half of that of D2 blades, and a potential choice for cost savings.     

Surface modifications of ZnO nanoparticles and their cytotoxicity

ZnO is a well-known UV absorber. At small particle sizes its absorption efficiency is substantially increased and this property, combined with transparency to visible light, has attracted growing interest in its applications in personal care products such as sunscreens. However, some recent studies suggest that ZnO nanoparticles could induce considerable toxicity to certain cells and microorganisms. Aiming to reduce cytotoxicity of ZnO nanoparticles without impairing their unique properties, this paper examines the influence of surface modifications to ZnO nanoparticles using coatings such as silica (SiO2) and Poly methyl Acrylic Acid (PMAA). It was found that both PMAA and SiO2 coatings were physically attached to the ZnO surface and their presence did not weaken UV absorption of the original nanoparticles. Uncoated ZnO and SiO2-coated ZnO exhibited similar cytotoxicity to human lymphoblastoid cells, while PMAA-coated ZnO nanoparticles had little adverse effect except at high concentrations. The type of coating was also shown to affect the generation of Reactive Oxygen Species (ROS). The correlation between cell viability and ROS level led to conclusions that enhanced oxidative stress could be one of the reasons for cytotoxicity of ZnO nanoparticles.     

Subjective and behavioral presence measurement and interactivity in the collaborative augmented reality game TimeWarp

Presence is usually assessed via a variety of subjective and objective measures. However, constraints often result in subjective measurements using questionnaires as a key method of data collection. In this paper we present a study of 44 participants of a collaborative augmented reality game known as TimeWarp which used both subjective and objective behavioral measures. Behavior as coded from video recordings of one scene of the game and self-reports about feelings of presence were compared. Our findings indicate that pointing behavior and verbal responses to the virtual content are correlated negatively to sense of presence. We further investigated the influence of subjectively perceived interactivity on perceived presence. We found that the interaction possibilities perceived by the participants predicted their experience of social presence with the virtual characters in the game. Furthermore, playing together with another person did not result in decreased social presence of the virtual characters. Implications for presence research are discussed.     

Optimized dairy grazing systems in the northeast United States and New Zealand. I. Model description and evaluation.

Parallels exist in the recent developments of dairy systems in the Northeast United States and New Zealand because of greater use of pasture grazing and feed supplements, respectively. Lessons can be learned from each system. However, major differences exist between the regions in the patterns of pasture production, the costs of supplementary feed, and milk prices. These differences affect the optimum use of feed. In this paper, a linear programming model developed to determine optimum feeding strategies for dairy systems in each country is presented. The model optimizes grazing management (rotation lengths) and the conservation of pasture subject to constraints on their use. Other feed resources include N fertilizer, grain, corn silage, and alfalfa silage. All feeds are represented in energy terms. The substitution of pasture intake by grain and forage supplements is included, and cow performance can be optimized by choosing from 73 seasonal calving herds that vary in calving date, lactation length, and daily milk production. The model predicts that marginal responses to grain feeding are between 1.35 and 1.8 kg of milk/kg of grain dry matter supplement, well within the range of responses reported in the literature. Evaluation of the model against data from nine grazing system treatments in New Zealand and two in Pennsylvania showed that model predictions averaged +3% (New Zealand) and +0.04% (Northeast) of measured milk production. The model could be used with confidence to study systems in both the Northeast United States and New Zealand.     

High Performance Organic Transistors Using Small Molecule Semiconductors and High Permittivity Semiconducting Polymers

High mobility organic semiconductor formulations with excellent uniformity across large area substrates are prepared via the use of formulations containing small molecule and high permittivity semiconducting oligomers. The use of these high‐k (k > 3.3) oligomers allows control of the wetting via the manipulation of the surface energy of the substrate being coated. Organic thin film transistors results with mobilities of up to 5 cm² V^‐1 s^‐1, standard deviation <10 %, on/off ratios of 10⁹ are presented.