H/sup /spl infin// control and estimation with preview-part I: matrix ARE solutions in continuous time

Preview control and fixed-lag smoothing allow a noncausal component in the controller/estimator. Time domain variational analysis is used in a reduction to an open loop differential game, leading to a complete, necessary and sufficient characterization of suboptimal values and an explicit state space design, in terms of a parameterized (nonstandard) algebraic matrix Riccati equation in a general continuous time linear system setting. The solution offers insight into the appropriate structure of the associated Hamiltonian, where the state and co-state are not the usual state of the original dynamic system and that of its adjoint. Rather, the state and co-state are selected to capture the respective lumped effects of initial data and future input selection in the allied game.     

Atmospheric aerosols over two sites in a southeastern region of Texas

Speciated samples of PM_2.5 were collected at the Bayland Park and Orange sites in Southeastern Texas by US EPA (Environmental Protection Agency) from July 2003 to August 2005. A total of 256 samples for the Bayland Park site and 293 samples for the Orange site with 52 species were measured; however, 22 species were excluded because of too many below‐detection‐limit data. Among the 22 species excluded, 19 species are common to both sites. The two data sets were analyzed by positive matrix factorization (PMF) to infer the sources of PM observed at the two sites. The analysis identified ten common source‐related factors: sulphate‐rich secondary aerosol I, sulphate‐rich secondary aerosol II, cement/carbon‐rich, wood smoke, motor vehicle/road dust, nitrate‐rich secondary aerosol, metal processing, soil, sea salt, and chloride‐depleted marine aerosol. sulphate and nitrate mainly exist as ammonium salts. The two sulphate‐rich secondary aerosols account for about 59% and 54% of the PM_2.5 mass concentration at the two sites, respectively. The factor containing highest concentrations of Cl and Na was attributed to sea salt due to the proximity of the monitoring sites to the Gulf of Mexico. The chloride‐depleted marine aerosol was related to the sea salt aerosol but was identified separately due to the chlorine replacement reactions. Basically, the factor of sulphate, nitrate, and soil at the two sites showed similar chemical composition profiles and seasonal variation that reflect the regional characteristics of these sources. The regional factors showed predominantly low frequency variations, however, the area‐related and local factors showed both high and low frequency variations. Motor vehicle/road dust, sea salt, and chloride‐depleted marine aerosol were likely to be area‐related factors. Cement/carbon‐rich, wood smoke, and metal processing factor were likely to be the local sources.     

H/sup /spl infin// control and estimation with preview-part II: fixed-size ARE solutions in discrete time

H/sup /spl infin// preview control and fixed-lag smoothing problems are solved in general discrete time linear systems, via a reduction to equivalent open-loop differential games. To prevent high order Riccati equations, found in some solutions, the state of the Hamilton-Jacobi system resides in a quotient space of an auxiliary extended state space system. The dimension of that auxiliary space is equal to the state space dimension of the original system (ignoring the delay).     

Design and implementation of an adaptive controller for torqueripple minimization in PM synchronous motors

This paper addresses the problem of torque ripple minimization in permanent magnet synchronous motors (PMSMs) and proposes an adaptive feedback structure as a solution. A model of PMSM that includes a torque ripple phenomenon is first developed and tested. While slightly different from the conventional one, our model is still compact and suitable for control. All parameters of the model have physical interpretation, and can either be measured directly or estimated in a numerically reliable procedure. An adaptive control algorithm is then described, enabling speed tracking while minimizing the torque ripple. Finally, the proposed algorithm is verified in simulations and implemented in a hardware setup. Experimental results show significant reduction of torque ripple (by 27 dB). Extensive analysis and simulations of hardware imposed limitations were performed as well, revealing and quantifying the issues that might affect practical ripple minimization performance     

Rheological analysis of stabilizing forces in wire-coating dies

A rheological analysis of a wire-coating die is presented. The rheological forces which might play a role in the stability of the wire are estimated. In particular, consideration is given to lateral forces related to the secondary normal stress function acting on the wire which is in an eccentric position, and the hydrodynamic force related to the viscosity function acting on the wire which moves at an angle to the die axis. For the former a simple, yet general, expression was derived by solving the flow problem (without axial pressure gradient) with the Ericksen equation in bipolar coordinates. Results indicate that normal stresses stabilize the wire, i.e., tend to restore it to the central location, provided the secondary normal stress function is negative. The hydrodynamic effect tends to reduce the angle between wire and die axes, thus drawing attention to the need of perfect mechanical centering of the guider tip, since in this case this effect also reduces eccentricity. The need is stressed for further work, in particular, experimental measurement of the secondary normal stress function.     

Melt solidification in polymer processing

This paper treats two cases of polymer melt solidification in rectangular geometry. The cases treated are the one of static solidification and that of solidification during flow in a narrow gap channel. Both cases are solved using the method of Dussinberre, which reduces the two-phase moving boundary case to a single phase problem, simplifying the mathematics considerably. The numerical solutions are based on a combination of the concept of flow analysis network (FAN), a finite element method developed for solving polymer flow problems, with a Crank-Nicolson implicit finite difference scheme. The methods may be used in computing the cooling down period and preventing “short” conditions in injection molding dies. Examples of solidification of high density polyethylene illustrate the applicability of the method.     

The Nehari problem in systems with distributed input delays is inherently finite dimensional

The Nehari problem is considered in the context of linear systems with distributed input (or, equivalently, output) lags. It is shown that both the computation of the optimal value and the parametrization of suboptimal solutions reduce to matrix computations in an associated undelayed Nehari problem. The solution is then given in terms of a system of Neutral type.     

Effect of proline on arginine uptake and nitrogen metabolism of lactating goats

The hypothesis that addition of proline may save dietary protein for milk production was tested by administration of proline to two goats through a duodenal cannula. Because proline is synthesized by the mammary gland in vitro from arginine, the effect of proline supplementation on arginine uptake by the gland was tested in vivo. Arginine uptake, calculated from arterio-venous difference, dropped significantly in both animals, especially in the morning 1 h after milking, when a low-protein diet was fed. Milk production and total nitrogen in milk were not affected significantly by proline supplementation. A trend was toward decrease of milk orotic acid and an increase of milk fat due to proline supplementation.     

Injection molding into a rectangular cavity with inserts

Advancing melt front profiles, pressures, and temperatures were measured during the filling stage of an injection molding process into a rectangular cavity with variously shaped inserts. These experimentally measured data, together with weldline location, were compared to predictions of the previously developed theoretical model.     

The urine of SLE patients contains antibodies that bind to the laminin component of the extracellular matrix

Direct immunofluorescence of tissues derived from patients affected with SLE demonstrates antibodies bound to the extracellular matrix (ECM). In the present work we have tested whether such antibodies are found in the serum and urine of lupus patients and mice. We found that the urine of patients with active SLE and of MRL/lpr/lpr mice contains antibodies that bind ECM and that a major target for these antibodies is the 200 kDa light chain of laminin which is one of the matrix components. The level of the anti-ECM, anti-laminin antibodies correlates with disease activity.