Topic
Deltar
About: Deltar is a research topic. Over the lifetime, 27 publications have been published within this topic receiving 427 citations.
Papers
TL;DR: By causal modeling, it is demonstrated that a high proportion of MDS and DeltaR was explained by h because of the nonlinearity of the physiological responses to weather d, and added new physiological insight into daily growth-climate relationships.
Abstract: Variation in tree stem diameter results from reversible shrinking and swelling and irreversible radial growth, all processes that are influenced by tree water status. To assess the causal effects of water and temperature on stem radial variation (DeltaR) and maximum daily shrinkage (MDS), the diurnal cycle was divided into three phases: contraction, expansion and stem radius increment. Diurnal cycles were measured during 1996-2004 in Picea abies (L.) Karst., Pinus cembra L. and Larix decidua Mill. in a timberline ecotone to understand the links between stem diameter variation (v; defined as MDS or DR), phase duration (h), and weather or sap flow descriptors (d). We demonstrated that a high proportion of MDS and DeltaR was explained by h because of the nonlinearity of the physiological responses to weather d. By causal modeling, we tested whether the relationship between d and v was due to h (lack of causal relationship between d and v) or to both d and h (double cause). The results of this modeling added new physiological insight into daily growth-climate relationships. Negative correlations were found between DeltaR and air temperature owing to the negative effect of temperature on h only, and did not correspond to a direct effect on tree growth mediated by an alteration in metabolic activities. Precipitation had two main effects: a direct effect on DeltaR and an indirect effect mediated through an effect on h. A reduction in sap flow at night led to an increase in DeltaR for P. abies and L. decidua, but not for P. cembra.
102 citations
TL;DR: In this article, it was shown that the arbitrary-radius-wire representation can be improved by modifying the material parameters for the axial field components closest to the wire as well as those for the radial electric and circulating magnetic field components.
Abstract: We have shown that finite-difference time-domain (FDTD) electromagnetic computations for a conductor system having a radius smaller than 0.15Deltar or larger than 0.65 Deltar (Deltar is the lateral side length of cells employed), modeled using arbitrary-radius-wire representations proposed so far with a time increment determined from the upper limit of Courant's stability condition, result in numerical instability. A primary factor causing this numerical instability is that the speed of waves propagating in the radial direction from the wire in the immediate vicinity of the wire exceeds the speed of light, and therefore, Courant's condition is not satisfied there. It is further shown that for these cases, the arbitrary-radius-wire representation can be improved by modifying the material parameters for the axial field components closest to the wire as well as those for the radial electric and circulating magnetic field components. The improved wire representation is effective in representing a wire whose radius ranges from 0.0001Deltar to 0.9Deltar.
67 citations
TL;DR: It is demonstrated unambiguously that the increase in magnetoresistance is correlated with an improvement in the quality of the interfaces in these MBE-grown materials.
Abstract: We report Co-59 NMR measurements on three MBE-grown Co/Cu(111) multilayer films that show a progression of saturation magnetoresistance from DELTAR/R = 4% to DELTAR/R = 40%. Our results demonstrate unambiguously that the increase in magnetoresistance is correlated with an improvement in the quality of the interfaces in these MBE-grown materials.
39 citations
TL;DR: In this article, design guidelines for composite polymeric microcantilevers with embedded piezoresistors are provided from the point of reducing their stiffness and to increase their deflection and the DeltaR/R response.
Abstract: Microfabricated cantilevers are widely used for biomedical sensing applications. In this paper, for the first time, design guidelines have been provided for composite polymeric microcantilevers with embedded piezoresistors. Optimization guidelines have been provided from the point of reducing their stiffness and to increase their deflection and the DeltaR/R response. Choice of the piezoresistive material and the location of this layer with respect to the neutral axis are shown to impact the stiffness and DeltaR/R of a microcantilever. Differences in the behavior of DeltaR/R and deflection, when surface stresses are applied to polymer based microcantilevers and oxide/nitride based ones, are brought out. We also show that it is essential to have the immobilization layer and the piezoresistor on the same side of the neutral axis particularly when these microcantivelers are used for sensing small surface stresses in the order of a few mN/m, typical of many molecular markers used in biomedical applications
27 citations
TL;DR: In this article, it was shown that a perfectly conducting wire has an equivalent radius, a 0 = 0.135 Deltar (Deltar is the lateral side length of rectangular cells used), if the tangential components of electric field along the wire axis are forced to zero in finite-difference time-domain (FDTD) calculations in the 2D cylindrical coordinate system.
Abstract: We have shown that a perfectly conducting wire has an equivalent radius, a 0 = 0.135 Deltar (Deltar is the lateral side length of rectangular cells used), if the tangential components of electric field along the wire axis are forced to zero in finite-difference time-domain (FDTD) calculations in the 2-D cylindrical coordinate system. Further, we have shown that the technique proposed by Noda and Yokoyama to represent a wire having an arbitrary radius in the 3-D Cartesian coordinate system can be applied successfully to representing such a wire in the 2-D cylindrical coordinate system if 0.135 Deltar is used instead of 0.230 Deltar for a 0.
25 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 1 |
| 2012 | 1 |
| 2008 | 2 |
| 2007 | 1 |
| 2006 | 1 |
| 2005 | 1 |