TimeLine: visualizing integrated patient records.

An increasing amount of data is now accrued in medical information systems; however, the organization of this data is still primarily driven by data source, and does not support the cognitive processes of physicians. As such, new methods to visualize patient medical records are becoming imperative in order to assist physicians with clinical tasks and medical decision-making. The TimeLine system is a problem-centric temporal visualization for medical data: information contained with medical records is reorganized around medical disease entities and conditions. Automatic construction of the TimeLine display from existing clinical repositories occurs in three steps: 1) data access, which uses an eXtensible Markup Language (XML) data representation to handle distributed, heterogeneous medical databases; 2) data mapping and reorganization, reformulating data into hierarchical, problemcentric views; and 3) data visualization, which renders the display to a target presentation platform. Leveraging past work, we describe the latter two components of the TimeLine system in this paper, and the issues surrounding the creation of medical problems lists and temporal visualization of medical data. A driving factor in the development of TimeLine was creating a foundation upon which new data types and the visualization metaphors could be readily incorporated.     

The Effects of Cure Temperature and Time on the Bulk Fracture Properties of a Structural Adhesive

The purpose of this investigation is to determine experimentally the possibility of optimizing the room temperature bulk fracture properties of structural adhesives with respect to cure temperature, time and cool-down conditions. The model adhesive, Metlbond, is a solid film modified nitrile epoxy resin supplied in two forms: Metlbond 1113 (supported with synthetic fabric carrier cloth) and Metlbond 1113-2 (without carrier cloth). The effects of carrier cloth on the bulk fracture properties are investigated as well. The uniaxial tensile strength and rigidity values were determined over a wide range of cure temperatures and times with fast and slow cool-down conditions during a previous investigation by the authors. For the present investigation, the fracture toughness of the model adhesives, subjected to opening mode failure, are experimentally determined, with the use of single-edge-cracked specimens, for different cure and cool-down conditions. It is found that the optimum fracture toughness values are obtained at low temperature-long time cure conditions in the absence of carrier cloth when slow cool-down condition is employed. Using the elastic-plastic material behavior assumption, it is shown that an average crack tip plastic zone radius can be determined using the fracture toughness and tensile strength values obtained corresponding to a given cool-down condition. These average plastic zone radii values are used along with the available tensile rigidity values to evaluate the optimum fracture energies of the model adhesives for a number of cure schedules. It is found that the optimum fracture energy levels are obtained at high temperature-short time cure conditions, using slow cool-down in the absence of carrier cloth.     

Constrained rigid body stability and control

Stability and control of a single or three‐body constrained system are considered. Several different types of constrained motion are among them: the impact phase of a free body colliding with the ground, contact with a stationary or moving platform, movement on a frictionless surface or multiple rigid bodies connected by holonomic constraints, and moving as in the human arm. The single body constrained system is controlled by sliding mode control. The stability of the three‐link arm at arbitrary equilibrium points and Lyapunov stability in the vicinity of the equilibrium point are formulated. The formulation and derivations are by computational tools, that is, state space analysis and matrices. The approach can easily be extended to larger systems with many rigid bodies such as skeletal systems. The formulation minimizes human labor in formulations and simulations. The sliding mode behavior of the model on a frictionless surface and the three link arm stability are demonstrated via simulation. Challenges for application to natural systems are outlined. Copyright © 2014 John Wiley & Sons, Ltd.     

Localization of hybrid controllers for manipulation on unknown constraints

A robotic control problem is proposed in which a six degree of freedom manipulator is to explore the surface of an object which isa priori unknown to the controller. Choice of an exploration strategy is discussed. The exploration strategy developed uses the maximal freedom of choice allowed under the restrictions of the problem. In particular, it is shown that any admissible reference trajectory can be used, provided it lies in a two-dimensional manifold which maps continuously into the surface. The inverse kinematic velocity problem is then solved using pseudo-inverses which fully exploit the redundancy of the system. The controller used as an example uses computed torque for linearization and compliant motion theory for movement along the desired path. The solution to the inverse kinematic problem together with the on-line generation of selection-mappings constitute a hybrid force/velocity controller. Successful exploration is shown to depend heavily on reliable force control, so PI force feedback is also proposed. Simulation and experimental results demonstrate the effectiveness of the overall design.This work was supported in part by the National Science Foundation under grant No. MSM-8700753 and in part by the Office of Naval Research under grant No. N00014-91-J-1621.     

A physicochemical route for compensation of molecular weight loss during recycling of poly(ethylene terephthalate)

This work is aimed to undertake the simultaneous effect of chain extension (chemical modification) and solid‐state polymerization (SSP) on the structural properties of recycled poly(ethylene terephthalate) to compensate the molecular weight (MW) losses caused by thermal degradation. This hybrid technique was qualified by tracking changes in the MW, intrinsic viscosity (IV), and concentrations of hydroxyl and carboxylic groups of various samples containing different concentrations of chain extender that experienced different residence times (2, 4, 6, 8, and 10 h) and different SSP process temperatures (190, 200, and 210°C). It was found that at high concentrations of chain extender, thermal degradation is facilitated owing to the lack of functional groups, as witnessed by a sharp drop in the MW and IV. The re‐recycled poly(ethylene terephthalates) experienced chemical modification followed by SSP physical treatment and revealed a rise in MW and IV. Accordingly, the synergistic effect of hybrid modification in comparison with the individual chemical modification was highlighted. J. VINYL ADDIT. TECHNOL., 22:387–395, 2016. © 2015 Society of Plastics Engineers     

On the Fluid Flow and Thermal Analysis of a Compliant Surface Foil Bearing and Seal

Foil gas bearings have been applied successfully to a wide range of high-speed rotating machinery such as air cycle machines (ACMs) and auxiliary power units (APUs). The performance of these bearings are based on the high pressure gas in a very thin layer between the journal and the bearing governed by the Reynolds equations. Generation of heat in these bearings especially at high journal rotating speed and high loads or at high ambient temperature directly affect their performance. Thermal and fluid flow analysis of an advanced compliant foil journal bearing/seal are presented. The side flow (known as leakage) and the approximate temperatures are the results of this analysis. The result of preliminary analysis shows that the major portion of the heat is carried through conduction and using the modified Couette flow approximation for the present working fluid, air, helped in analysis of the temperature magnitude, which can be related to the gas viscosity behavior and thin gas film thicknesses.     

Applying a dual extended Kalman filter for the nonlinear state and parameter estimations of a continuous stirred tank reactor

The extended Kalman filter (EKF) provides an efficient method for generating approximate maximum-likelihood estimates of the states or parameters of discrete-time nonlinear dynamical systems. In this paper, we consider the dual-estimation problem, the so-called dual EKF, in which both the states of a dynamical system and its parameters are estimated simultaneously, given only noisy observations. The main contribution of this paper is to show the efficacy of a proposed simplified dual-EKF technique (which in this work will be referred to as the dual EKF-2) in comparison with the conventional joint EKF. This has been demonstrated by conducting simulation studies on a CSTR which has been dynamically simulated using the HYSYS simulation package. Extensive analysis revealed that, not only the dual-EKF approach can achieve optimal state- and parameter-estimation performances comparable to the joint EKF, but also it has the main advantage of carrying out separate estimations of the states and parameters.     

On the capabilities of the double-layer representation for Stokes flows. Part I. Analytical solutions

Boundary-integral equations of the second kind for Stokes flows known as the completed-double-layer (CDL) representations are promising formulations for the solution of many-body problems in suspension mechanics. It is therefore important to analyze their numerical properties for geometries where accurate numerical results are not readily obtained. In this paper, several analytical and semi-analytical results are derived for the double-layer representation where particles are in close proximity to one another. In particular, the onset of spatial oscillation of the surface density is explored as a function of particle-particle separation. These oscillations are not spurious and pose a significant challenge for discretization schemes.     

On The Dynamic and Thermal Performance of a Zero Clearance Auxiliary Bearing(zcab) for a Magnetic Bearing System

Structural and thermal analysis of a zero clearance auxiliary bearing (ZCAB) for magnetic bearing systems is presented. The ZCAB consists a series of rollers whose centers are initially placed on a circle. At the open condition all rollers have an initial clearance about the rotating shaft. As the shaft drops on the ZCAB rollers, either due to failure of the magnetic bearing system or a transient shock, the centers of the rollers move circumferentially along a curve path and after eliminate the initial clearance by closing around the shaft and re-centering it. This is known as the closed condition. The overall stiffness of the ZCAB will then depend on the stiffness of each single roller and the initial clearance between the rollers and the shaft. This is affected by the number of rollers that will touch the shaft which will also vary the load applied on the rollers. The low shaft-rollers traction coefficient and overall dynamic support characteristics obviate the possibility of backward whirl, however this traction and the generated heat in the rolling element embedded in the rollers are sources of heat generation. This paper presents the results of a transient analysis for the ZCAB structural stiffness. A preliminary thermal model of the ZCAB and comparison between the predictions and test results are also discussed. Some design guidelines are presented to help improve the performance of the ZCAB in the case of high temperature working conditions.