The equivalent temperature coefficient of resistance of thin film resistor-conductor structures

Using the basic definition of the temperature coefficient of resistance (TCR), we developed a theoretical method for estimating the effect of the high TCR of conductors on the final TCR of resistor-conductor systems.

To investigate the relations developed, we studied several thin film resistors on various substrates. The experimental results for the combined TCR of the resistor-conductor systems correspond well with the theoretically predicted values.     

Patient behavior in hospitals: Helplessness, reactance, or both?

48 male inpatients hospitalized for 1, 3, or 9 wks and 24 male outpatients (mean age of all Ss, 39.9 yrs) were tested on cognitive tasks; poor performance and depressive symptoms increased with length of hospitalization, even as illness resolved. Further, increased hospitalization made patients more susceptible to the debilitating effect of uncontrollable events. Taken together, these results imply that the passive, compliant, and inanimate behavior of the "good patient" may be the result of learned helplessness engendered by hospitalization. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studies on vesicourethral reflexes. II. Urethral sphincteric responses to spinal cord stimulation

A bipartite bladder model was developed with and without complete muscular separation in order to isolate and analyze separately sphincteric and detrusor responses. Spinal cord stimulation of the sacral micturition center evoked responses in the detrusor compartment as well as in the urethral sphincteric compartment. The micturition center was easily definable in the spinal cord at a variable point lying in the segment L51/2 to L6 vertebral levels. It was not possible to isolate a separate detrusor center from a sphincteric center. They did overlap-with the sphincteric center extending both above and below the detrusor center. Parameters of stimulation were tested and it was noted that 1 to 3 v, frequency of 10 to 15 cps, and duration of 1 msec gave the optimal responses. Complte muscular separation did not alter sphincteric response to spinal cord stimulation. Nerve-mediated impulses resulted in rise in detrusor pressure and a simultaneous rise in urethral pressure that interfered with proper voiding and hindered bladder emptying. This problem remains to be solved before central spinal cord stimulation for the purpose of controlled bladder evacuation becomes fully effective.     

Nonlinear black-box models in system identification: Mathematical foundations

We discuss several aspects of the mathematical foundations of the nonlinear black-box identification problem. We shall see that the quality of the identification procedure is always a result of a certain trade-off between the expressive power of the model we try to identify (the larger the number of parameters used to describe the model, the more flexible is the approximation), and the stochastic error (which is proportional to the number of parameters). A consequence of this trade-off is the simple fact that a good approximation technique can be the basis of a good identification algorithm. From this point of view, we consider different approximation methods, and pay special attention to spatially adaptive approximants. We introduce wavelet and ‘neuron’ approximations, and show that they are spatially adaptive. Then we apply the acquired approximation experience to estimation problems. Finally, we consider some implications of these theoretical developments for the practically implemented versions of the ‘spatially adaptive’ algorithms.     

Effect of molybdenum,niobium, and vanadium on static recovery and recrystallization and on solute strengthening in microalloyed steels

The effect of molybdenum, niobium, and vanadium on the occurrence of static recovery and recrystallization after high temperature deformation was investigated in a series of microalloyed steels. The steels had a base composition of 0.05 pct C and 1.40 pct Mn. To this, single additions of 0.30 pct Mo, 0.035 pct Nb, and 0.115 pct V were made. Interrupted hot compression tests were performed at 900 and 1000 °C, and at a constant true strain rate of 2 s^-1. The load-free time was decreased from 5000 s to 50 ms, and the degree of static softening during this period was determined. Both graphite and glass were used as lubricants. Percent softeningvs delay time curves are presented and the retarding effect of molybdenum, niobium, and vanadium addition on the rate of static recovery and recrystallization is discussed. The greatest solute retardation of static recovery and recrystallization is produced by niobium addition, followed by that of molybdenum, vanadium leading to the smallest delay. Although the rank order of this effect is the same as found under dynamic softening conditions, the relative contribution of niobium is more profound for the static condition. The solute strengthening attributable to each element was also assessed, and found to follow the same order as for the recovery and recrystallization results. At 900 °C, the onset of the static precipitation of Nb (CN) was detected at approximately 10 seconds, somewhat earlier than previously reported. Formerly Graduate Student at McGill University, Montreal, Quebec.     

Shear behavior of flexible polyurethane foams under uniaxial compression

The mechanisms behind the load building capabilities of a hyperbranched polymer (HBP) in polyurethane (PU) foams have been investigated, using microscopy techniques and mechanical analyses. By broadening the traditional uniaxial compression characterization of PU foams to include combined shear deformations and compression behavior, an apparent Poisson ratio of the foam could be obtained in situ. The Poisson ratio as function of uniaxial compression ratio of the foam was thus studied for foams filled with Styrene Acrylonitrile (SAN) and foams containing HBP. Generally a window of deformation ratios could be defined in which the Poisson ratio was negative. The width of this window varied systematically with the SAN loading, where an increase in SAN particle loading resulted in a broadening of the negative Poisson ratio window. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Foliar Spraying of Silicon Associated with Salicylic Acid Increases Silicon Absorption and Peanut Growth

Silicon - Silicon (Si) combined with foliar spraying of salicylic acid (SA) can affect the absorption of this beneficial element. A study with Si non-accumulators plants (soybean and bean) observed...