The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

The Bulletin of Environmental Contamination and Toxicology provides rapid publication of peer-reviewed articles describing significant advances and discoveries in the fields of air, soil, water, and food contamination and pollution as well as articles on methodology and other disciplines concerned with the introduction, presence and effects of toxicants in the total environment.  With its high standards of scientific quality and clarity, the Bulletin provides a meeting ground for research workers who daily encounter problems related to the contamination of our environment and who welcome opportunities to share in new discoveries as soon as they are made.

Bulletin of Environmental Contamination and Toxicology

Many radial basis function (RBF) methods contain a free shape parameter that plays an important role for the accuracy of the method. In most papers the authors end up choosing this shape parameter by trial and error or some other ad hoc means. The method of cross validation has long been used in the statistics literature, and the special case of leave-one-out cross validation forms the basis of the algorithm for choosing an optimal value of the shape parameter proposed by Rippa in the setting of scattered data interpolation with RBFs. We discuss extensions of this approach that can be applied in the setting of iterated approximate moving least squares approximation of function value data and for RBF pseudo-spectral methods for the solution of partial differential equations. The former method can be viewed as an efficient alternative to ridge regression or smoothing spline approximation, while the latter forms an extension of the classical polynomial pseudo-spectral approach. Numerical experiments illustrating the use of our algorithms are included.

/pdf/on-choosing-optimal-shape-parameters-for-rbf-approximation-4673pg6gmn.pdf

On choosing “optimal” shape parameters for RBF approximation

This chapter describes the methodology used in EPA’s Waste Reduction Model (WARM) to estimate streamlined life-cycle greenhouse gas (GHG) emission factors for concrete beginning at the point of waste generation. The WARM GHG emission factors are used to compare the net emissions associated with concrete in the following two waste management alternatives: recycling and landfilling. Exhibit 1 shows the general outline of materials management pathways for concrete in WARM. For background information on the general purpose and function of WARM emission factors, see the Introduction & Overview chapter. For more information on Recycling and Landfilling, see the chapters devoted to these processes. WARM also allows users to calculate results in terms of energy, rather than GHGs. The energy results are calculated using the same methodology described here but with slight adjustments, as explained in the Energy Impacts chapter.

나의 Concrete 연구실

The purpose was to determine if definable trends appear when comparisons arc made between the nutrient absorption capacities of various typcs of fresh water wetlands. The review showed that there are few data available for comparison. with the exception of Nand P in above ground vegetation. Data from mass balance studies are almost nonexistent. which makes it impossible to determine the conditions necessary for specific types of wetlands to annually lose. gain. or be in balance with regard to nutrient fluxes. The only discern able trend was that wetlands with predominantly organic substrates accumulated less Nand P in the above ground vegetation, yet the peat substrates seem to be capable of long-term storage of Nand P. Recommendations for future research on nutrient dynamics in fresh water wetlands arc discussed. (KEY TERMS: nutrient dynamics; fresh water; wetlands; nitrogen; phosphorus.)

Wetland Functions and Values: The State of Our Understanding

Pervious concrete pavements in low-traffic urban areas such as parking lots reduce storm water runoff and also minimize water pollution. However, there are concerns about their expected clogging and consequential reduction of hydraulic performance in the long run. The pervious concrete pavements can be declogged using rejuvenation methods such as vacuum sweeping, or pressure washing, or a combination of both. This paper presents the results of our study that focused on the hydraulic performance of pervious concrete pavements. The study included field and laboratory investigations to evaluate the infiltration capacities of the pervious concrete cores and the underlying soils and the usefulness of rejuvenation methods in restoring their hydraulic performance. As a result of this research program, a new field test device, called the embedded ring infiltrometer, was developed for evaluating the infiltration rates of newly installed pervious concrete pavements. The results of this study indicate that the rejuvenation methods can substantially restore the performance of pervious concrete pavements for better management of storm water.

Effect of Rejuvenation Methods on the Infiltration Rates of Pervious Concrete Pavements

An updated Lagrangian finite-element formulation has been developed for time-dependent problems of soil consolidation involving finite deformations. Large plastic strains as well as rotations occur in such problems and nominal stress measures are introduced in the formulation to redefine stresses. This leads to corrective terms for equilibrium and yield violations in addition to geometric stiffening terms in the governing integral equations. The soil is considered to be either a linear elastic or an elastoplastic, critical-state material. Some simple numerical examples are studied to validate the formulation, followed by a detailed analysis of the problem of penetration of a pile into soil. The results of this problem are viewed with emphasis on the physical interpretation and practical significance.

Finite-element analysis of time-dependent large-deformation problems

SECTION 1: FRACTURE MECHANICS AND FATIGUE Numerical Green's function applied to fracture mechanics: 3-D implementation Developments in the use of the dual boundary element method for the fracture analysis of plate bending problems Dynamic fracture mechanics with crack edges contact interaction Dynamic dual boundary element analysis for 3-D fracture mechanics Failure analysis of gears using the boundary element method Probability based computation of life expectancy of mechanical structures Trends in the stochastic BEM. SECTION 2: INELASTIC PROBLEMS Inelastic analysis without cell by improved multiple-reciprocity BEM Accurate evaluations of strongly singular domain integrals in non-linear BEM A fully regulated direct boundary formulation for three-dimensional elastoplastic problems Homogenization of grain structure. SECTION 3: CONTACT MECHANICS A comparison between non-conforming node-to-point and weak approaches in contact problem by BEM Adaptive solution of rolling contact using boundary element method A method to compute the effect of groups of frictional bolts BEM analysis of the contact problem in fibres debonded of a matrix. Effects of curing stresses. SECTION 4: ELECTROMAGNETICS Time domain boundary element analysis of resistively loaded wire The steady-state wave process in a piezoceramic medium with cavities (plane deformation). SECTION 5: COMPUTATIONAL TECHNIQUES Galerkin method in time domain BEM analysis On time-dependent domain integral approximation using radial basis functions Efficient domain calculation in direct boundary element method The residual as an error estimator in the BEM Constructing adaptive boundary elements for the Poisson-type nonlinear problem An estimate of numerical errors by means of boundary integral equations Regularizing transformationmethod for evaluation of singular and near-singular integrals Parallel Laplace transform boundary element methods for diffusion problems r-Adaptive boundary element method A new error indicator based on stresses for adaptive meshing with Hermite boundary elements Panel clustering for 3-D elastostatics using spherical harmonics A BEM-formulation applied to the solution of nonlinear dynamic problems A boundary-only BEM for linear and nonlinear problems Application of finite-dimensional perturbation technique to boundary integral equations Theory and practice of superconvergence based a posteriori error estimation in a Galerkin boundary element method. SECTION 6: INVERSE PROBLEMS Green's functions in the numerical solution of some inverse boundary value problems 3-D impedance tomography of high contrast objects An efficient inverse BEM algorithm to characterize space dependent thermal conductivity with an evolutionary-genetic approach. SECTION 7: FLUID DYNAMICS AND AERODYNAMICS Integral formulation of non-steady convective diffusion problem with high source term value An indirect boundary element method for slow viscous flow in a bounded region subject to surface tension forces Parallel indirect multipole BEM analysis of Stokes flow in a multiply connnected domain An asymptotic boundary element method for the 2D Stokes problem in the vorticity formulation Rayleigh-Benard convection of non-Newtonian fluid Leaky and confined aquifer flow analysis using 3D BEM Unsteady free surface flow around hydrofoils A comparison of different radial basis functions in DRBEM solution of the Navier-Stokes equations Emergence of nonlinear dynamics in 3D cavity mixing of Newtonian and viscoelastic (linear) fluids Estimation of physical unknowns in submerged breakwater using nonlinear least squares-boundary element method. SECTION 8: ACOUSTICS The dual reciprocity method for Helmholtz-type operators A generalized Helmholtz equation fundamental solution using a conformal mapping and dependent variable transformation Boundary element analysis of certain structural-acoustic coupling problems and its application Applications of a new composite BIE for 3-D acoustic problems Muffler analysis using the direct mixed-body boundary and an efficient four-pole approach Application of boundary element methods in modeling multidimensional flame-acoustic interactions. SECTION 9: CORROSION Finite resistivity and shipboard corrosion prevention system performance Boundary element model of electrochemical dissolution with geometric non-linearities A general formulation based on the boundary element method for the analysis of grounded installations in layered soils. SECTION 10: ELASTODYNAMICS Determination of 3D time domain responses in latered media by using a coupled BE/FE process Modeling of turbo-generator rotors using BEM Boundary element dynamic non-linear stress analysis by mass matrix approach The boundary element method applied to transient dynamic anistropic problems. SECTION 11: THERMAL PROBLEMS Transient conduction-radiation problems: dual reciprocity solution Improvement of the frit salvage process for a cathode ray tube Extension of the dual reciprocity boundary element method to the problems of phase-change and thermal wave propagation Boundary integral formulation for non-linear heat conduction in anistropic heterogeneous media Boundary element analysis of conduction problems FVM/BEM approach for the solution of non-linear conjugate heat transfer problems. SECTION 12: GEOMETRICALLY NON-LINEAR PROBLEMS Solution of 2D, 3D and axisymmetric finite deformation problems by the boundary-domain integral method On incremental equilibrium equations in solid mechanics.

Boundary elements XX

Stormwater runoff from highways is a source of pollution to surface water bodies and groundwater. Excess loadings of phosphorus in stormwater discharged to surface water bodies can result in eutrophication. Treatment of stormwater for phosphorus is necessary in order to sustain ecological and economical benefits related to aquatic resources. If phosphorus is removed, the water can be sustained for other uses, such as irrigation and industrial applications. The data presented in this paper is used to evaluate the treatment performance of a roadside biosorption activated media system with regards to the removal of total phosphorus and soluble reactive phosphorus from highway runoff. The evaluation also compares removal efficiencies and effluent concentrations using biosorption activated media (BAM) to that with sandy soil commonly found in the Florida area. The results presented in this paper indicate that BAM bio-filtration systems are a feasible treatment method for removing phosphorus from highway runoff. A discussion concerning the additional treatment and reuse of water by harvesting, as part of a Bio-filtration & Harvesting Swale System, is also presented in the paper.

/pdf/assessment-of-biosorption-activated-media-under-roadside-wqrsk700w8.pdf

Assessment of Biosorption Activated Media Under Roadside Swales for the Removal of Phosphorus from Stormwater

Portland cement pervious concrete’s ability to infiltrate water has encouraged its use for stormwater management However, the material has suffered historically poor acceptance due to a lack of data related to long term infiltration rates and rainfall retention which leads to an undefined credit for stormwater management Before stormwater management credit could be estimated, it was necessary to develop a testing device to gather information from existing pervious concrete parking lots currently in use Eight parking lots were examined to determine the infiltration rates of the pervious concrete, as well as to assess the soil makeup beneath pavement A total of 30 pavement cores were extracted and evaluated for infiltration rates Three of the sites had a pervious concrete section that included a gravel reservoir Infiltration rates were measured using the application of an embedded single-ring infiltrometer A mass balance model to simulate the hydrologic and hydraulic function of pervious concrete sections was developed The purpose of the model is to predict runoff and recharge volumes for different rainfall conditions and hydraulic properties of the concrete and the soil The field derived hydraulic data were used to simulate infiltration volumes and rainfall excess given a year of rainfall as used in a mass balance operated within a spreadsheet The results can be used for assessing stormwater management credit

/pdf/hydraulic-performance-assessment-of-pervious-concrete-1wey9ae64m.pdf

Manoj Chopra

Papers

Effect of Rejuvenation Methods on the Infiltration Rates of Pervious Concrete Pavements

Finite-element analysis of time-dependent large-deformation problems

Boundary elements XX

Assessment of Biosorption Activated Media Under Roadside Swales for the Removal of Phosphorus from Stormwater

Hydraulic Performance Assessment of Pervious Concrete Pavements for Stormwater Management Credit