Search results for "equation"
showing 10 items of 4219 documents
Computation of flow velocity in rough channels
2006
Accurate estimate of flow-velocity profile is of crucial importance both for scientific purposes and for solving numerous engineering problems that include, among others, sediment transport, contaminant transport, flow resistance evaluation. This paper presents a new empirical equation to represent the vertical velocity profile. The proposed equation is essentially a modified form of the well-known logarithm law of the wall and contains three parameters having a clear physical meaning. The applicability of the equation and its accuracy assessment for different hydraulic conditions, including non-uniform conditions, is verified by using experimental data obtained by different sources. The va…
Empirical relationships for monitoring water quality of lakes and reservoirs through multispectral images
2014
Remote sensing techniques can be used to estimate water quality variables such as chlorophyll ${\mbi a}$ , total suspended particles, and water transparency. This paper describes empirical algorithms for the estimation of these variables using Landsat Thematic Mapper (TM) data. Ground data were taken from several Spanish lakes covering a variety of trophic statuses, ranging from oligotrophic to hypereutrophic. The studied lakes were the Albufera de Valencia and lakes and ponds of the Southeast Regional Park in Madrid. Empirical equations were obtained to estimate chlorophyll ${\mbi a}$ from the ratio in reflectance values between bands 2 and 4 of TM ( $\bf{ R^2 \, {\mmb =}\, 0.66}$ , ${\bf …
Short-duration rainfalls in Sicily
1990
The Italian Hydrographic Service publishes yearly maximum rainfall depths with 1-, 3-, 6-, 12-, and 24-hr duration, recorded by recording rain gauges. It also publishes selected short-duration (t<1 hr) rainfall amounts. It is impossible to carry out a statistical analysis of the short-duration rainfalls for each recording rain gauge because the published data correspond to different record durations and to different recording rain gauges from year to year. Therefore, there is a practical need to derive empirical relationships between the 1-, 3-, 6-, 12-, and 24-hr duration amounts and shorter duration (t<1 hr) rainfall amounts. Such a relationship has been proposed by Bell and has been veri…
The Antecedents of Customer Loyalty - Results of an Empirical Study in the Automotive Industry
2015
Customer satisfaction is regarded as the key to customer loyalty in the automotive industry. However, this relationship is influenced by several other variables, like switching barriers or variety seeking. This paper provides a structural equation model with latent variables for modeling this complex relationship. According to literature, high satisfaction should lead to loyalty but is heavily affected by moderating variables. An empricial study is reported which supports these predictions as well as the arguments on which they are based.
Radiating and non-radiating sources in elasticity
2018
In this work, we study the inverse source problem of a fixed frequency for the Navier's equation. We investigate that nonradiating external forces. If the support of such a force has a convex or non-convex corner or edge on their boundary, the force must be vanishing there. The vanishing property at corners and edges holds also for sufficiently smooth transmission eigenfunctions in elasticity. The idea originates from the enclosure method: The energy identity and new type exponential solutions for the Navier's equation.
Polymerisation von äthylenoxid mit dem kaliumalkoholat von 4-benzolazo-benzylalkohol. II. Die quantitative bestimmung einer übertragungsreaktion
1966
Die Untersuchung von Polyathylenoxiden, die mit dem Kaliumalkoholat von 4-Benzolazo-benzylalkohol und Athylenoxid erhalten wurden, ergab, das nicht jedes Polyathylenoxidmolekul eine Endgruppc aus dein Polymerisationsstarter enthielt. Die vermutete Ubertragungsreaktion mit Wasserspuren wurde folgendermasen nachgewiesen und quantative bestimint. Eine quantitative Umsetzung der Polyathylenoxide mit(4-Benzolazobenzoesa-)anhydrid gab mittels colorimetrischer Messungen den Gehalt an HO-Endgruppen. Der Vergleich des Gehaltes an Endgruppen aus dem Starter mit dem HO-Endgruppengehalt zeigte ein starkes Uberwiegen der HO-Endgruppen. Die Zahlenmittel der Molekulargewichte (Mn) von Polyathylenoxidfrakt…
TRANSIENT SEMICONDUCTOR DEVICE SIMULATION INCLUDING ENERGY BALANCE EQUATION
1992
An efficient numerical method for the solution of hot‐carrier transport equations describing transient processes in submicrometer semiconductor devices is proposed. The calculations of transient processes in submicrometer MOS transistor were carried out and compared with the results obtained by conventional drift‐diffusion model.
Closed-form solutions of the energy balance equation for drip laterals under the Darcy-Weisbach resistance formula
2018
Many studies have investigated easy methods to design drip laterals, as well as the best resistance equation to use, which is fundamental to accurately account for friction losses. This paper addresses both the features of lateral design relationships and the influence of the friction-loss equation on the design variables. First, simple closed-form solutions of the energy balance equation for both sloped and horizontal drip laterals are derived with the simplified Darcy-Weisbach resistance formula by assuming the Darcy friction factor as invariant versus the Reynolds number. Second, an error analysis is performed assuming the friction factor as constant in the design, which is compared to u…
Determination of Nonuniform Residual Stresses Using the Ring-Core Method
1996
This paper considers residual stress analysis using the ring-core method. In particular, the so-called integral equation method is applied to evaluate nonuniform residual stress fields. The proposed method overcomes typical drawbacks of the incremental strain method which lead to incorrect results for strongly varying stress fields. The experimental results obtained with a specimen subjected to a bending load confirm the theoretical predictions.
A multilayer anisotropic plate model with warping functions for the study of vibrations reformulated from Woodcock's work
2013
Abstract In this paper, a suitable model for static and dynamic analysis of inhomogeneous anisotropic multilayered plates is described. This model takes into account the variations of the transverse shear strains through the thickness of the plate by means of warping functions. Warping functions are determined by enforcing kinematic and static assumptions at the interfaces. This model leads to: a 10×10 stiffness matrix coupling to each other the membrane strains, the bending and torsion curvatures, and the x and y-derivatives of the transverse shear strains; and a classical 2×2 transverse shear stiffness matrix. This model has been proven to be very efficient, especially when high ratios be…