Rate sensitivity of high birefringent fiber optic sensors underlarge dynamic loads

New experimental studies on the effects of large dynamic compressive loads on highly birefringent optical fibers are presented. The intensity rate of applied dynamic loads ranged between 2.18-6719 KN/m-sec. A Fibercore (previously York) HB600 Bow-Tie fiber with an initial beat length of 1.16 mm was employed in the present study. Sensor response is discussed in terms of the effects of force amplitudes and velocities on the calibration parameter T_f. T_f is a function of the amplitude as well as the velocity of applied loading. Therefore, calibration of the sensor should be achieved through regression analysis of the load-fringe data for the entire spectrum of the desired force velocities. The ramification of this finding is that a single experiment for the measurement of T_f cannot provide the required parameters for calibration. This further implies that the change in beat length is also dependent on the amplitude and velocity of loading. The suggested method takes both effects into account through empirical analysis of experimental data     

An observation system simulation experiment for the impact of landsurface heterogeneity on AMSR-E soil moisture retrieval

Using a high-resolution hydrologic model, a land surface microwave emission model (LSMEM), and an explicit simulation of the orbital and scanning characteristics for the advanced microwave sensing radiometer (AMSR-E), an observing system simulation experiment (OSSE) is carried out to assess the impact of land surface heterogeneity on large-scale retrieval and validation of soil moisture products over the U.S. Southern Great Plains using the 6.925 GHz channel on the AMSR-E sensor. Land surface heterogeneity impacts soil moisture products through the presence of nonlinearities in processes represented by the LSMEM, as well as the fundamental inconsistency in spatial scale between gridded soil moisture imagery derived from in situ point-scale sampling, numerical modeling, and microwave remote sensing sources. Results within the 575000 km² Red-Arkansas River basin show that, for surfaces with vegetation water contents below 0.75 kg/m², these two scale effects induce root mean squared errors (RMSEs) of 1.7% volumetric (0.017 cm_water³/cm_soil³ ) into daily 60 km AMSR-E soil moisture products and RMS differences of 3.0% (0.030 cm_water/3cm_soil³ ) into 60 km comparisons of AMSR-E soil moisture products and in situ field-scale measurements of soil moisture sampled on a fixed 25-km grid     

Calculation of contingency in construction projects

This paper presents a probabilistic model that considers the random nature of change orders and their impact on the cost and schedule of a construction project. The model incorporates uncertainties in project cost and schedule and calculates the contingency based on the level of confidence specified by the owner. It assumes a Poisson arrival pattern for change orders in a construction project. The effect of schedule delays in further increasing the project cost is considered explicitly and the effect of correlation between change orders is discussed and analytically considered. The proposed model may be used for budgeting purposes at the early stages of project development. Typical applications of the proposed model in the context of construction industry are discussed. A numerical example is presented that demonstrates the use of the model in establishing a budget contingency. The results of the example are compared with actual data from previous construction projects.     

The method of fundamental solutions with dual reciprocity for diffusion and diffusion–convection using subdomains

The method of fundamental solutions (MFS), first proposed in the 1960s, has recently reappeared in the literature and solutions of an extraordinary accuracy have been reported using relatively few data points. The method requires no mesh and therefore no integration, and has been recently combined with dual reciprocity method (DRM) for treating inhomogeneous terms. The objective of this paper is the combination of the two methods for treating convective terms which are derivatives of the problem variable. First the formulation of the methods for mixed Neumann–Dirichlet boundary conditions is considered, as both these types of boundary condition are necessary for this type of problem. Next a formulation for the usual Crank–Nickleson and Galerkin time-stepping procedures is obtained for both diffusion and diffusion–convection and the use of the subdomain technique with MFS is considered. Finally results obtained for some test problems are presented including a diffusion convection problem with variable velocity using both a single domain and a division into subregions, the convective terms being modeled using DRM. Results are compared with exact solutions and in some cases with DRBEM examples from the literature.