bluuebunny/crossref_metadata_2025 huggingface dataset:
Implications of climate change scenarios for soil erosion potential in the USA
Authors: Phillips D. L. , White D. , Johnson B.
Published: February 2007

Atmospheric general circulation models (GCMs) project that increasing atmospheric concentrations of CO2 and other greenhouse gases May, result in global changes in temperature and precipitation over the next 40‐100 years. Equilibrium climate scenarios from four GCMs run under doubled CO2 conditions were examined for their effect on the climatic potential for sheet and rill erosion in the conterminous USA. Changes in the mean annual rainfall factor (R) in the Universal Soil Loss Equation (USLE) were calculated for each cropland, pastureland and rangeland sample point in the 1987 National Resources Inventory. Projected annual precipitation changes were assumed to be from differences in either storm frequency or storm intensity. With all other USLE factors held constant these changes in R translated to changes in the sheet and rill erosion national average of +2 to +16 per cent in croplands, ‐2 to +10 per cent in pasturelands and ‐5 to +22 per cent in rangelands under the eight scenarios. Land with erosion rates above the soil loss tolerance (T) level and land classified as highly erodible (eredibility index >8) also increased slightly. the results varied from model to model, region to region and depended on the assumption of frequency versus intensity changes. These results show the range of sensitivity of soil erosion potential by water under projected climate change scenarios. However, actual changes in soil erosion could be mitigated by alterations in cropping patterns and other management practices, or possibly by increased crop growth and residue production under higher atmospheric CO2 concentrations.
Spreading deserts or spatially confined environmental impacts? land degradation and cattle ranching in the kalahari desert of botswana
Authors: Perkins J. S. , Thomas D. S. G.
Published: February 2007

The Kalahari Desert of Botswana is being increasingly used for livestock production, particularly through the establishment of ranches dependent on borehole water supplies. Reports of the environmental impacts of land use practices in such drylands are conflicting, with livestock systems supplied by boreholes and wells being regarded in some studies as centres for the spread of desertification and in others as having environmental impacts that are overridden by the effects of natural climatic variability. the results of an environmental study focused on a block of borehole ranches established in the eastern Kalahari as part of Botswana's Tribal Grazing Lands Policy dating from the 1970s are reported. the investigations concentrated on ecological, soil chemistry and soil erosion impacts on the study ranches. Although important changes in the ecology and soil nutrient status of the ranches are identified, their contribution to environmental degradation must be viewed in terms of stocking levels, The radial nature of range usage, giving rise to marked spatial variations in impact, and natural climatic variability. Changes are not solely detrimental, but long‐term monitoring, especially in relation to climatic fluctuations, needs to be undertaken to fully establish the dynamic interactions of variables.
Soil erosion and redistribution on cultivated and uncultivated land near las bardenas in the central Ebro river Basin, Spain
Authors: Quine T. A. , Navas A. , Walling D. E. , Machin J.
Published: February 2007

The semiarid regions of Spain, including the central part of the Ebro River basin, are under threat due to desertification. Severe erosion, as a result of poor land management, has led to degradation of the soil resource, and there is a clear need for quantitative erosion rate data to evaluate the problem. This study aimed to examine the potential for using caesium‐137 to identify the patterns and rates of soil erosion and redistribution within this semiarid environment. Samples for the determination of caesium‐137 were collected from uncultivated slopes and cultivated valley floor sites near the head and outlet of a small representative basin in the Las Bardenas area. The measured patterns of caesium‐137 mobilization, redistribution and export provide a semiquantitative indication of the variation in erosion within the study site. Calibration of the caesium‐137 measurements, taking account of the differing behaviour of radiocaesium on cultivated and uncultivated land, allows estimation of the actual rates of erosion and deposition involved. The results show (1) the erosion rates on the cultivated land (1.6–2.5 kg m−2 yr−1) are typically more than five times those seen on the uncultivated land (0.2–0.4 kg m−2 yr−1), and (2) erosion on the uncultivated land is significantly less severe at the head of the basin than at the outlet. Study of the vegetation cover suggests that lower growing shrubs and grasses may be more effective in reducing erosion in this environment than trees.
Agroforestry techniques for the rehabilitation of degraded salt‐affected lands in India
Authors: Singh G. , Singh N. T. , Abrol I. P.
Published: February 2007

The development of appropriate technologies for the judicious use of India's 8.11 million ha of salt‐affected lands would give increased food, fodder and fuelwood production. A sizeable portion of the salt‐affected lands of the Indo‐Gangetic plain have been reclaimed through chemical amendments and are being commercially used for arable farming. However, large areas of salt‐affected common lands, village and government lands and waste lands near cities, along railway tracks and roads do not have any productive use. Owing to their sparse vegetative cover such lands are vulnerable to further degradation and can be a source of runoff causing floods, especially where cows congregate. Research at the Central Soil Salinity Research Institute, Karnal has generated agroforestry techniques which could enable the economic exploitation of such marginal lands. This paper deals with various aspects of these techniques, which have been applied to over 50 000 ha by 1994.

Based on eight to ten years of growth and biomass figures, the most salt‐tolerant woody species identified were: Prosopis juliflora, Acacia nilotica, Casuarina equisetifolia, Tamarix articulata, Leptochloa fusca (a palatable forage grass which was found to be a promising primary colonizer of salt lands). Agronomic practices for the successful establishment of trees such as planting methods, amendment use, irrigation, spacing and lopping schedules are discussed. A Prosopis juliflora‐leptochloa fusca silvipastoral model was found to be excellent for fuelwood and forage production and for the amelioration of high pH soils. This system, when followed for little more than four years, reclaims alkali soils to such an extent that normal agriculture crops such as Trifolium alexandrinum and T. resupinatum can be grown successfully. A ridge‐trench system of tree planting was found to be helpful in alkali soils, the in situ rainwater conservation it led to assisting biomass production. Eucalyptus tereticornis, Populus deltoides and Tectona grandis based agroforestry were promising for reclaimed salt‐affected lands. The short‐ and long‐term effects of various tree plantations on the physicochemical properties of the soil and on soil‐water relations are also discussed. Agroforestry options for the development of salt‐affected lands found in various agroclimatic zones of India are explored.
The rehabilitation of degraded soils in eastern bolivia by subsoiling and the incorporation of cover crops
Authors: Barber R. G. , Navarro F.
Published: February 2007

A high proportion of the soils in the central zone of Santa Cruz, eastern Bolivia, are chemically and physically degraded, with low organic matter and N contents, compacted subsoil layers and a propensity to crusting, hardsetting and wind erosion. The aim of the experiment discussed in this paper was to identify suitable cover crops to be used in combination with subsoiling for the rehabilitation of degraded soils and the improvement of crop yields in eastern Bolivia. Fertilizers were not used because of their high cost. An experiment with a split complete block design, with subsoiling and no‐subsoiling as the main treatments, 14 cover crops and a continuously cultivated soybean/wheat control as the subtreatments, and four replications, was established on a degraded site comprising a mosaic of two compacted siliceous isohyperthermic soils (a coarse loamy Typic Ustropept and a fine loamy Typic Haplustalf). After a two‐year fallow period, the cover crops were incorporated and test crops were sown for five seasons to evaluate the effects of the treatments on subsequent crop yields. Soil samples were taken to measure changes in chemical fertility. The only significant cover crop effect on soil nutrients was an increase in exchangeable K from 0.47 to 0.56 cmolc kg−1 by Lablab; subsoiling had no effect on chemical fertility. For all treatments there was an average 24 per cent increase in soil organic matter from 13.1 g kg−1 at 3 months after cover crop incorporation to 16.3 g kg−1 at 19 months after incorporation. No significant differences in total N were found during this period. Test crop yields were not influenced by subsoiling, but were significantly increased by some of the cover crops as compared to the soybean/wheat control during the first three seasons only. Evidence from foliar analysis suggests that the effects of the cover crops on soybean yields were not nutritional and so presumably were physical in nature, whereas the benefits on wheat yields were possibly related to increased N availability. Panicum maximum var. Centenario and P. maximum var. Tobiatá gave the highest total yield increases over the first three cropping seasons (101 and 85 per cent, respectively), but these yield increases would not compensate the farmer for the loss of four crop harvests whilst the land was in fallow. These results highlight the difficulties of rehabilitating soil fertility and increasing crop yields through the use of subsoiling and cover crop fallows on compacted, low organic matter soils in eastern Bolivia.
Loess erosion in relation to land‐use changes in the ganspoel catchment, central Belgium
Authors: Fu B. , Gulinck H. , Masum M. Z.
Published: February 2007

This paper examines the changes of land uses and landscape patterns in the Ganspoel Catchment, central Belgium, using aerial photography interpretation (photographs taken in 1947, 1969 and 1986). The comparison of land cover areal changes and a transition matrix were used to assess land‐use changes in time and space. The size, fractal dimension and elongation index of patches were quantified for landscape pattern analysis. Grassland increased and farmland decreased in the study area from the 1940s to the 1980s. Forest increased from 1947 to 1969 and decreased from 1969 to 1986. About 49 per cent of the study area experienced changes of land use between 1947 and 1969, and about 36 per cent between 1969 and 1986. The landscape of the study area is more fragmented than it was in the 1940s. Patches have generally increased in number and decreased in size, although the landscape was most fragmented in 1969; fractal dimension of patches are lower, indicating less complex shapes. From 1969 to 1986, 59 per cent of the area of change was on 0–3 degree slopes, and from 1969 to 1986 6.7 per cent was on >8 degree slopes. Changing land uses and landscape patterns may have important ecological implications.
Geomorphic estimates of the stability of a uranium mill tailings containment cover: Nabarlek, Northern Territory, Australia
Authors: Riley S. J.
Published: February 2007

The geomorphic stability of the cover (cap) over the pit of Nabarlek Uranium Mine in Arnhem Land, Northern Australia, is important because radon gas and other long‐lived radio‐nuclides arising from mill tailings must be contained for long periods. The primary agents of denudation in the region's seasonally wet tropical environment of low relief are rainwash, overland flow, rilling and gullying. Other agents of erosion are of less concern, although biogenic agents of erosion (e.g. termites and windthrow) may enhance fluvial activity.

A combination of modelling, using the Universal Soil Loss Equation, and analogue estimates of denudation and thresholds of rilling and gullying from areas with similar geology, topography and climate are used to estimate the stability of the Nabarlek cover. Denudation rates are conservatively estimated at less than 100mm ky−1. It is suggested that with some minor design modifications the cover will retain its integrity for several thousand years.
Condition of rehabilitated coal mines in the Hunter Valley, Australia
Authors: Dragovich D. , Patterson J.
Published: February 2007

Legislation requiring the rehabilitation of new opencast coal mines came into effect in New South Wales, Australia, in 1973. Mining companies now stockpile original topsoil which is later spread with fertilizer over re‐shaped overburden and waste carbonaceous material. Problems in successfully revegetating new surfaces are exacerbated by the thinness and infertility of natural soils, which are deficient in phosphorus and moderately acid. Revegetation has not been successful on untreated mine waste and overburden. This study provides a general overview of some aspects of post‐rehabilitation soil chemistry and vegetation on these soils. A limited number of samples, collected from three mine sites having different rainfall and varying ages of rehabilitated areas, were tested for pH, EC, organic carbon, total phosphorus and available aluminium. Rehabilitated areas were all characterised by very low levels of total phosphorus, neutral pH, and variable and relatively low organic carbon, and some showed aluminium toxicity. Heavy application of gypsum at one of the steeper sites was associated with acid pH, high EC values, low total P, Al toxicity, some soil erosion and little plant cover. Except for this site, the variable vegetation cover at the sites studied seemed adequate for long‐term re‐establishment, despite serious weed invasion at some non‐studied sites, soil loss on newly re‐formed surfaces, and generally poor natural and rehabilitated soils.
An approach to land‐use planning in a hilly watershed using geographical information system
Authors: Adinarayana J. , Krishna N. Rama
Published: February 2007

The eco‐socio‐economic balance of a region can be preserved by proper land‐use planning, particularly in hilly watersheds where erosion caused by rainfall is an ever‐present threat. This paper describes a methodology developed to compile a treatment‐oriented land‐use planning scheme for a hilly watershed using a geographical information system (GIS). A remote sensing based physiographic soils map and a digital elevation model (DEM) are the sources of soil depth and slope steepness classes, respectively, and are the information databases for GIS analysis. The GIS was used to integrate these databases and provide tools for manipulation of the data. A set of knowledge‐based rules was formed from the classification scheme formulated by Sheng and Stennett (1975) for hilly watersheds, modified to allow for the local land‐use patterns. These rules were used to manipulate the databases and allow the establishment of a sustained land‐use system in the watershed with proper soil and water conservation measures. This biological engineering scheme would be a safeguard against soil erosion and other environmental threats. A priority sub‐watersheds delineation survey conducted in the watershed indicates significant variation in the silt yield index values, which calls for conservation planning in earnest in cases of high and very high priority sub‐watersheds.
The influence of parent material on soil fertility degradation in the coastal plain of Tanzania
Authors: Hartemink A. E. , Bridges E. M.
Published: February 2007

Differences in the vulnerability of soils to fertility degradation are compared for two major soil groups located in the coastal plain of Tanzania and cropped with sisal (Agave sisalana). Ferralsols derived from intermediate gneiss of Precambrian age and Cambisols developed in Jurassic and Neogene limestones partly covered with Quaternary deposits were selected for comparison. A clear influence of parent material was apparent when soils were continuously cropped with sisal and no fertilizers were applied. Serious soil fertility decline occurs in Ferralsols, but Cambisols are resilient to chemical degradation and the fertility decline in these soils was very limited. The differences in degradation rates are explained by the lower initial fertility and low nutrient reserve of Ferralsols, while the Cambisols had higher initial fertility levels and nutrients removed by the sisal crop are replenished by the weathering of the underlying parent material. Sustainable soil fertility management of Cambisols includes only NPK fertilization, but heavy dressings of lime, organic manures and/or chemical fertilizers are required to improve the fertility status of the Ferralsols and to produce crops in a sustainable manner.
Interaction of (Hydroxypropylmethyl)cellulose with Anionic Surfactants
Authors: de Martins Ricardo M. , Becker Cristiane M. , Samios Dimitrios , Bica Clara I. D.
Published: February 2007

The aggregation process between (hydroxypropylmethyl)cellulose (HPMC 0.20% m/m) and three anionic surfactants namely sodium cholate (CS), sodium deoxycholate (DC) and sodium dodecylsulphate (SDS), in aqueous dilute solutions, was investigated by fluorescence, electrical conductivity, dynamic light scattering (DLS) and small angle X‐ray scattering (SAXS) techniques. Through fluorescence, the critical micelle concentration (CMC) and critical aggregation concentration (CAC) of the systems were obtained in good agreement with those obtained from conductivity. Also by means of conductivity measurements, once the experiments were undertaken at four temperatures, the thermodynamic parameters of the micellization process were calculated. From DLS, the relaxation time distribution functions were analyzed by REPES Routine, revealing that the surfactants bind to the polymer before CAC as well as the formation of free micelles at high surfactant content. The SAXS technique confirmed the existence of such free micelles.
Characterization and Properties of Some Polysaccharides Used as Biomaterials
Authors: Rinaudo Marguerite
Published: February 2007

This paper described three natural or pseudo natural polysaccharides often used as biomaterials. Their development opens a large field of applications taking advantage of their specific properties (renewable, biodegradable, biologically active). They are good thickeners and/or gelling polymers in determined thermodynamic conditions. As many polysaccharides they are rich in OH groups allowing stabilization of H bonds network and giving good film forming properties. The polysaccharides described in this paper are water soluble and have a net charge which allows to form electrostatic complexes which are much developed for biomedical or pharmaceutical applications.
Generalized financial ratios
Authors: Nadarajah Saralees , Kotz Samuel
Published: January 2007

Ratios of random variables are prevalent in finance. Examples include: current ratio, sales margin, changes in capital employed, interest cover, liabilities ratio and financial leverage ratio. In this note, we derive the exact distribution of the ratio X/(X + Y) when X and Y are independent generalized Pareto random variables, Pareto distribution being the first and the most popular distribution used in finance. Copyright © 2007 John Wiley & Sons, Ltd.
Numerical modelling of fault generation in the extensional tectonic regime of the Gulf of Corinth
Authors: Stavropoulou M.
Published: January 2007

The aim of this work is to investigate the extent to which a relatively simple mechanical model (both at constitutive and boundary conditions levels) can reproduce the main features of a typical extensional part of European continent such as the Gulf of Corinth (or Korinthos). A second step is performed here for the investigation of this problem, following a first one consisted of appropriate downscaled sandbox model tests and continuum mechanics numerical modelling. A more suitable numerical method, namely the distinct element method implemented in Universal Distinct Element Code (UDEC), is employed in this second attempt to study faulting and the associated deformations in extensional tectonic regimes. The hypothesis that an inherited listric normal fault with high dip angle ( ∼ 60°) at the surface transforming into a gently dipping normal fault at larger depths ( ∼ 10° ) subjected to extensional strain rate may reproduce the major structural features of the Gulf is herein investigated. This study shows that sliding on the listric fault produces a second high‐angle antithetic normal fault that initiates at the point of change of curvature of the initial listric fault and propagates upwards until it reaches the surface. A second model that takes into account both listric and antithetic faults as boundary conditions, produces under extension, a third normal fault dipping as the first master listric fault and initiating close to the root of the antithetic fault, ultimately propagating upwards up to the free surface. Finally, a third model that starts with the three faults, results in a system of conjugate normal faults lying between the master listric fault and the first antithetic fault. This structure of normal faults resembles closely both the structure of normal faults observed at the Gulf of Corinth and the history of their formation, indicating that the Gulf is a half‐graben. Copyright © 2007 John Wiley & Sons, Ltd.
An operator‐split ALE model for large deformation analysis of geomaterials
Authors: Di Y. , Yang J. , Sato T.
Published: January 2007

Analysis of large deformation of geomaterials subjected to time‐varying load poses a very difficult problem for the geotechnical profession. Conventional finite element schemes using the updated Lagrangian formulation may suffer from serious numerical difficulties when the deformation of geomaterials is significantly large such that the discretized elements are severely distorted. In this paper, an operator‐split arbitrary Lagrangian–Eulerian (ALE) finite element model is proposed for large deformation analysis of a soil mass subjected to either static or dynamic loading, where the soil is modelled as a saturated porous material with solid–fluid coupling and strong material non‐linearity. Each time step of the operator‐split ALE algorithm consists of a Lagrangian step and an Eulerian step. In the Lagrangian step, the equilibrium equation and continuity equation of the saturated soil are solved by the updated Lagrangian method. In the Eulerian step, mesh smoothing is performed for the deformed body and the state variables obtained in the updated Lagrangian step are then transferred to the new mesh system. The accuracy and efficiency of the proposed ALE method are verified by comparison of its results with the results produced by an analytical solution for one‐dimensional finite elastic consolidation of a soil column and with the results from the small strain finite element analysis and the updated Lagrangian analysis. Its performance is further illustrated by simulation of a complex problem involving the transient response of an embankment subjected to earthquake loading. Copyright © 2007 John Wiley & Sons, Ltd.
Inexact Barzilai‐Borwein method for saddle point problems
Authors: Hu Yi‐Qing , Dai Yu‐Hong
Published: January 2007

This paper considers the inexact Barzilai–Borwein (BB) algorithm applied to saddle point problems. To this aim, we study the convergence properties of the inexact BB algorithm for symmetric positive definite linear systems. Suppose thatgkandg̃kare the exact residual and its approximation of the linear system at thekth iteration, respectively. We prove theR‐linear convergence of the algorithm if ∥g̃k–gk∥⩽η∥g̃k∥ for some small η>0 and allk. To adapt the algorithm for solving saddle point problems, we also extend theR‐linear convergence result to the case when the right‐hand term ∥g̃k∥ is replaced by ∥g̃k–1∥. Although our theoretical analyses cannot provide a good estimate to the parameter η, in practice, we find that η can be as large as the one in the inexact Uzawa algorithm. Further numerical experiments show that the inexact BB algorithm performs well for the tested saddle point problems. Copyright © 2007 John Wiley & Sons, Ltd.
Preconditioning CGNE iteration for inverse problems
Authors: Egger H.
Published: January 2007

The conjugate gradient method applied to the normal equations (CGNE) is known as efficient method for the solution of non‐symmetric linear equations. By stopping the iteration according to a discrepancy principle, CGNE can be turned into a regularization method, and thus can be applied to the solution of inverse, in particular, ill‐posed problems. We show that CGNE for inverse problems can be further accelerated by preconditioning in Hilbert scales, derive (optimal) convergence rates with respect to data noise, and give tight bounds on the iteration numbers. The theoretical results are illustrated by numerical tests. Copyright © 2007 John Wiley & Sons, Ltd.
Modified Hermitian and skew‐Hermitian splitting methods for non‐Hermitian positive‐definite linear systems
Authors: Li Liang , Huang Ting‐Zhu , Liu Xing‐Ping
Published: January 2007

To further study the Hermitian and non‐Hermitian splitting methods for a non‐Hermitian and positive‐definite matrix, we introduce a so‐called lopsided Hermitian and skew‐Hermitian splitting and then establish a class of lopsided Hermitian/skew‐Hermitian (LHSS) methods to solve the non‐Hermitian and positive‐definite systems of linear equations. These methods include a two‐step LHSS iteration and its inexact version, the inexact Hermitian/skew‐Hermitian (ILHSS) iteration, which employs some Krylov subspace methods as its inner process. We theoretically prove that the LHSS method converges to the unique solution of the linear system for a loose restriction on the parameter α. Moreover, the contraction factor of the LHSS iteration is derived. The presented numerical examples illustrate the effectiveness of both LHSS and ILHSS iterations. Copyright © 2007 John Wiley & Sons, Ltd.
The retraction algorithm for factoring banded symmetric matrices
Authors: Kaufman Linda
Published: January 2007

Let A be an n × n symmetric matrix of bandwidth 2m + 1. The matrix need not be positive definite. In this paper we will present an algorithm for factoring A which preserves symmetry and the band structure and limits element growth in the factorization. With this factorization one may solve a linear system with A as the coefficient matrix and determine the inertia of A, the number of positive, negative, and zero eigenvalues of A. The algorithm requires between 1/2nm2 and 5/4nm2 multiplications and at most (2m + 1)n locations compared to non‐symmetric Gaussian elimination which requires between nm2 and 2nm2 multiplications and at most (3m + 1)n locations. Our algorithm reduces A to block diagonal form with 1 × 1 and 2 × 2 blocks on the diagonal. When pivoting for stability and subsequent transformations produce non‐zero elements outside the original band, column/row transformations are used to retract the bandwidth. To decrease the operation count and the necessary storage, we use the fact that the correction outside the band is rank‐1 and invert the process, applying the transformations that would restore the bandwidth first, followed by a modified correction. This paper contains an element growth analysis and a computational comparison with LAPACKs non‐symmetric band routines and the Snap‐back code of Irony and Toledo. Copyright © 2007 John Wiley & Sons, Ltd.
An inverse problem in estimating the relaxation time for nanoscale phonon radiative transfer problem
Authors: Huang Cheng‐Hung , Chen Kuan‐Yu , Kim Sin
Published: January 2007

An inverse nanoscale phonon radiative transfer problem is solved in this study by using conjugate gradient method (CGM) to estimate the unknown frequency‐ and temperature‐dependent relaxation time, based on the simulated phonon intensity measurements. The CGM in dealing with the present integro‐differential governing equations is not as straightforward as for the normal differential equations; special treatments are needed to overcome the difficulties. Results obtained in this inverse analysis will be justified based on the numerical experiments where two different unknown distributions of relaxation time are to be estimated. Finally, it is shown that the reliable frequency and temperature‐dependent relaxation time can be obtained with CGM. Copyright © 2007 John Wiley & Sons, Ltd.
A simple computer implementation of membrane wrinkle behaviour via a projection technique
Authors: Akita T. , Nakashino K. , Natori M. C. , Park K. C.
Published: January 2007

A simple computer implementation of membrane wrinkle behaviour is presented within the classical elastic plane stress constitutive model. In the present method, a projection technique is utilized for modelling of the wrinkle mechanisms, in which the total strains in wrinkled membranes are decomposed into elastic and zero‐strain energy parts, and a projection matrix that extracts the elastic parts from the total strains is derived. The resulting modified elasticity matrix that represents the stress–strain relations in wrinkled membranes is thus obtained as product of the classical elasticity matrix and the projection matrix. The modified elasticity matrix is straightforward to implement within the context of the finite element method. Numerical examples are presented to demonstrate the accuracy and effectiveness of the proposed method. Copyright © 2007 John Wiley & Sons, Ltd.
Dynamic identification of fractal structures
Authors: Tesar Alexander , Melcer Jozef
Published: January 2007

Dynamic identification of fractal structures mapping the configurations from the nature and adopted in advanced structural engineering is dealt with in the present paper. Theoretical, numerical and experimental assessments are based on wave approaches and back‐propagation neural network models corresponding with genetic algorithms. Some structural applications based on such assessments are presented. Copyright © 2007 John Wiley & Sons, Ltd.
A discontinuous Galerkin method for a hyperbolic model for convection–diffusion problems in CFD
Authors: Gómez H. , Colominas I. , Navarrina F. , Casteleiro M.
Published: January 2007

This paper proposes a hyperbolic model for convection–diffusion transport problems in computational fluid dynamics (CFD). The hyperbolic model is based on the so‐called Cattaneo's law. This is a time‐dependent generalization of Fick's and Fourier's laws that was originally proposed to solve pure‐diffusive heat transfer problems. We show that the proposed model avoids the infinite speed paradox that is inherent in the standard parabolic model.

A high‐order upwind discontinuous Galerkin (DG) method is developed and applied to classic convection‐dominated test problems. The quality of the numerical results is remarkable, since the discontinuities are very well captured without the appearance of spurious oscillations. These results are compared with those obtained by using the standard parabolic model and the local DG (LDG) method and with those given by the parabolic model and the Bassi–Rebay scheme.

Finally, the applicability of the proposed methodology is demonstrated by solving a practical case in engineering. We simulate the evolution of pollutant being spilled in the harbour of A Coruña (northwest of Spain, EU). Copyright © 2007 John Wiley & Sons, Ltd.
On some fluid–structure iterative algorithms using pressure segregation methods. Application to aeroelasticity
Authors: Badia Santiago , Codina Ramon
Published: January 2007

In this paper we suggest some algorithms for the fluid–structure interaction problem stated using a domain decomposition framework. These methods involve stabilized pressure segregation methods for the solution of the fluid problem and fixed point iterative algorithms for the fluid–structure coupling. With one single loop the solution of the coupled system tends to one of the strongly coupled monolithic systems. These coupling algorithms are applied to the aeroelastic simulation of suspension bridges. We assess flexural and torsional frequencies for a given inflow velocity. Increasing this velocity we reach the value for which the flutter phenomenon appears. Copyright © 2007 John Wiley & Sons, Ltd.
An investigation into blood donation intentions among non‐donors
Authors: Reid Mike , Wood Angela
Published: January 2007

In broad terms, the donation of blood along with organ and bone marrow donation is considered to be the ultimate act of humanity involving a voluntary and anonymous exchange between two people of a life saving commodity. Yet motivating people to donate blood is a significantly difficult task. The aim of this paper is to use the Theory of Planned Behaviour (TPB) to examine non‐donors on the basis of their likely intention to donate blood in the future and to identify barriers on these more favourable non‐donors. This exploratory research finds that subjective norm, perceived behavioural control and time related barriers are related to intent to donate by current non‐donors. Differences between higher and lower intention donors are also explored.

Copyright © 2007 John Wiley & Sons, Ltd.
Synthesis and characterization of poly(L‐lactide‐co‐ε‐ caprolactone) copolymers: influence of sequential monomer addition on chain microstructure
Authors: Nalampang K. , Molloy R. , Punyodom W.
Published: January 2007

A series of copolymers with various compositions were synthesized by one‐step and two‐step bulk ring‐opening polymerizations of L‐lactide (LA) and ε‐caprolactone (CL) using stannous octoate [Sn(Oct)2] and 1‐hexanol as the initiating system. For the sequential two‐step polymerization, a poly(ε‐caprolactone) (PCL) prepolymer was polymerized first to a percent conversion of approximately 70% and LA then added in order to produce a copolymer with a chain microstructure different from that obtained from the corresponding one‐step reaction. The resulting copolymers were characterized using a combination of nuclear magnetic resonance spectroscopy (1H‐ and 13C‐NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and gel permeation chromatography (GPC). The average sequence lengths of the lactidyl ($l_{{\rm LL}}^{\rm e}$) and caproyl ($l_{{\rm cap}}^{\rm e}$) units, the degree of randomness (R) and the transesterification coefficient (T(II)) were calculated from the 13C‐NMR spectra. The appearance of a signal due to CapLCap sequences was directly attributable to transesterification of lactidyl (LL) units. It was found that both $l_{{\rm LL}}^{\rm e}$ and $l_{{\rm cap}}^{\rm e}$ values from the two‐step syntheses were significantly longer than from the corresponding one‐step syntheses, leading to different semi‐crystalline morphologies and chain microstructures. The copolymers all showed at least some blocky chain structure as a result of the significant difference in monomer reactivity (LA > CL) between LA and CL. Thermal properties including stability depended on both composition and chain microstructure which could be controlled by the method of synthesis. From their DSC curves, the two‐step copolymers were seen to be semi‐crystalline whereas the one‐step copolymers were mainly amorphous. A more blocky microstructure, as obtained from the two‐step method, appeared to result in a lower thermal stability. Copyright © 2007 John Wiley & Sons, Ltd.
Fatal adenovirus hepatitis during maintenance therapy for childhood acute lymphoblastic leukemia
Authors: Steiner Isabelle , Aebi Christoph , Ridolfi Lüthy Annette , Wagner Bendicht , Leibundgut Kurt
Published: February 2007

Disseminated adenoviral infection with hepatitis is rare in children undergoing standard chemotherapy. We report on a 3½‐year‐old male with fatal adenovirus hepatitis receiving maintenance chemotherapy for acute lymphoblastic leukemia (ALL). Adenoviral hepatitis was proven by histology, viral culture, and PCR in a liver biopsy. Quantitative real‐time PCR in the peripheral blood showed adenoviral DNA copy number >109/ml. Despite aggressive supportive care and antiviral treatment with cidofovir, the patient died rapidly due to fulminant liver failure. Diagnostic and treatment options for adenovirus infection remain unsatisfactory for these patients. We propose suggestions for diagnosis and therapy. Pediatr Blood Cancer 2008;50:647–649. © 2007 Wiley‐Liss, Inc.
Successful treatment with modified CHOP‐rituximab in pediatric AIDS‐related advanced stage Burkitt lymphoma
Authors: Crosswell Howland E. , Bergsagel Daniel J. , Yost Robert , Lew Glen
Published: February 2007

Burkitt lymphoma is the most common AIDS‐related lymphoma (ARL) in childhood. The major issues in adult and pediatric ARL include identifying the optimal chemotherapy regimen and the concurrent treatment of both rituximab and highly active anti‐retroviral therapy (HAART). We present a case of advanced stage Burkitt lymphoma in an 8‐year‐old female with acquired immunodeficiency syndrome (AIDS), who was successfully treated with a 3 month course of modified CHOP‐R (cyclophosphamide, daunorubicin, vincristine, prednisone, and rituximab) and HAART therapy. The combination of rituximab and chemotherapy with HAART therapy may be well‐tolerated and effective in HIV/AIDS patients with Burkitt lymphoma. Pediatr Blood Cancer 2008;50:883–885. © 2007 Wiley‐Liss, Inc.
Synthesis and characterization of cross‐shaped p–n diblock oligomers
Authors: Wang Hong‐Yu , Wan Jun‐Hua , Jiang Hong‐Ji , Wen Gui‐An , Feng Jia‐Chun , Zhang Zhi‐Jian , Peng Bo , Huang Wei , Wei Wei
Published: February 2007

The cross‐shaped p–n diblock oligomers based on oligothiophenes (OTs) and 1,3,4‐oxadiazole (OXD) were synthesized and investigated regarding optical properties, electrochemistry, quantum chemical calculations, and intramolecular energy transfer. Since only one emission peak is observed in PL spectra of the oligomers, it is evidenced that effective energy transfer from the OXD to OTs branch. The electrochemical experiments show that almost complete spatial separation of HOMO and LUMO with the thiophene number increasing. The theoretical calculations were carried out regarding which conformer is the lowest in energy, the torsion angle between thiophene/oxadiazole and the central benzene ring, and electron densities distributions of the oligomers. Based on all data, a model for intramolecular energy‐transfer process has been put forward to explain the optical properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1066–1073, 2007
Novel electroluminescent cationic polyelectrolyte based on poly[(fluorene‐2,7‐diylvinylene)‐alt‐(1,4‐phenylenevinylene)] and its precursor
Authors: Mikroyannidis John A. , Barberis Vasilis P. , Cimrová Věra
Published: February 2007

A novel conjugated poly[(fluorene‐2,7‐vinylene)‐alt‐(1,4‐phenylenevinylene)] derivative 2 with quaternizable tertiary amino groups was synthesized by Heck coupling of a substituted 2,7‐dibromofluorene and 1,4‐dialkoxy‐2,5‐divinylbenzene. The corresponding quaternary ammonium cationic polyelectrolyte 3 was obtained by the treatment of 2 with bromoethane. Both polymers were soluble in common organic solvents, like tetrahydrofuran, chloroform, and dichloromethane. Polymer 3 showed a limited solubility in alcohols and was insoluble in water. Photophysical and electrochemical properties of the resulting polymers were fully investigated. An intensive green photoluminescence (PL) with maxima at 550 and 545 nm was observed from thin films of 2 and 3 polymers, respectively, red‐shifted compared with the PL emission spectra measured in the solution. The electrochemical band gaps were 2.38–2.45 eV. Single‐layer and double‐layer (with poly[3,4‐(ethylenedioxy)thiophene]/poly (styrenesulfonate) (PEDOT:PSS)) light‐emitting devices (LEDs) with ITO and Al electrodes were prepared and studied. They emitted a green light and their electroluminescence (EL) spectra were similar to those of PL thin films. The external EL efficiency was determined to be 0.43 and 0.32% for ITO/PEDOT:PSS/2/Al and ITO/PEDOT:PSS/3/Al LEDs, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1016–1027, 2007
Thermodynamic model of gas permeability in polymer membranes
Authors: Lee Do Kyoung , Kim Yong Woo , Lee Kyung Ju , Min Byoung Ryul , Kim Jong Hak
Published: February 2007

A new molecular thermodynamic model is developed of the gas permeability in polymer membranes on the basis of configurational entropy and Flory‐Huggins theory to predict permeability dependence on the concentration of penetrant. Three kinds of configurational entropy are taken into account by this model; that is, the disorientation entropy of polymer, the mixing entropy, and specific interaction entropy of polymer/gas. The validity of the mathematical model is examined against experimental gas permeability for polymer membranes. Agreement between experimental and predicted permeability is satisfactory. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 661–665, 2007
Magnetoresistance, transport noise and granular structure in polycrystalline superconductors
Authors: García‐Fornaris I. , Govea‐Alcaide E. , Muné P. , Jardim R. F.
Published: February 2007

In this work we present a theoretical study on the magnetic field dependence of the electrical resistance R (Ba) and the transport noise (TN) in a high‐Tc polycrystalline superconductors. In the model, we have considered the ceramic superconductor as a series‐parallel array of Josephson devices and the intergranular magnetic field is described within the framework of the intragranular flux‐trapping model. The obtained results qualitatively reproduce the hysteretic behavior of the R (Ba) dependence in increasing and decreasing applied magnetic fields. We have found that the hysteretic behavior in the R (Ba) dependence changes appreciably if different statistical distributions of the geometric factors of grains are used. In addition, such changes are also reflected in the TN, which is produced by the electric current rearrangement in the array with increasing applied magnetic fields. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonparametric confidence intervals for Tmax in sequence‐stratified crossover studies
Authors: Willavize Susan A. , Morgenthien Elizabeth A.
Published: January 2007

Tmax is the time associated with the maximum serum or plasma drug concentration achieved following a dose. While Tmax is continuous in theory, it is usually discrete in practice because it is equated to a nominal sampling time in the noncompartmental pharmacokinetics approach. For a 2‐treatment crossover design, a Hodges–Lehmann method exists for a confidence interval on treatment differences. For appropriately designed crossover studies with more than two treatments, a new median‐scaling method is proposed to obtain estimates and confidence intervals for treatment effects. A simulation study was done comparing this new method with two previously described rank‐based nonparametric methods, a stratified ranks method and a signed ranks method due to Ohrvik. The Normal theory, a nonparametric confidence interval approach without adjustment for periods, and a nonparametric bootstrap method were also compared. Results show that less dense sampling and period effects cause increases in confidence interval length. The Normal theory method can be liberal (i.e. less than nominal coverage) if there is a true treatment effect. The nonparametric methods tend to be conservative with regard to coverage probability and among them the median‐scaling method is least conservative and has shortest confidence intervals. The stratified ranks method was the most conservative and had very long confidence intervals. The bootstrap method was generally less conservative than the median‐scaling method, but it tended to have longer confidence intervals. Overall, the median‐scaling method had the best combination of coverage and confidence interval length. All methods performed adequately with respect to bias. Copyright © 2007 John Wiley & Sons, Ltd.
Reducing costs by using value engineering on superfund projects
Authors: Braden Merle
Published: February 2007

This article informs the remediation community about value technology and how the technologies of remediation and value engineering (VE) have been successfully combined. The article describes to the practitioner how the first value engineering study on Superfund work was initiated by the Corps of Engineers for EPA.
Field‐scale rotary kiln incineration: Oxygen responses at the kiln, afterburner, and stack
Authors: Leger C. B. , Cundy V. A. , Sterling A. M. , Montestruc A. N. , Jakway A. L. , Owens W. D.
Published: February 2007

There currently exists a need for better characterization and simulation of the processes that occur during the incineration of hazardous wastes in the environment of a rotary kiln. Addressing this need, a comprehensive research program was formed with the goal of developing a rudimentary predictive capability for rotary kiln incineration of hazardous wastes. This comprehensive program is headed by Louisiana State University and includes interaction with the University of Utah and also various industrial participants. Such cooperation allows use of laboratory, pilot, and field scale equipment. While laboratory scale experiments provide the necessary decoupling of complex phenomena and a high degree of experimental control, and pilot scale studies provide more realism at the expense of experimental control, the problems of scale‐up make generalization of results to field scale units very tenuous. The unique aspect of the LSU program is the coupling of the laboratory and pilot scale units with afield scale unit in order to overcome these generalizations.

In this study, plastic packs containing a mixture of toluene and sorbent were fed to a field‐scale rotary kiln incinerator at a rate of one pack every 10 minutes. Selected continuous gas samples and temperatures were obtained from the exit of the rotary kiln, from the afterburner, and from the stack. These measurements were obtained during various operating conditions. These data provide, for the first time, an ability to compare conditions in the kiln to simultaneous conditions in the afterburner and stack.

This paper outlines several new experimental features of our field‐scale tests conducted in October 1990. Oxygen responses from the kiln, the afterburner, and the stack are compared during various operating conditions.
Status and trends in bioremediation treatment technology
Authors: Fox Catherine A.
Published: February 2007

This article is a critical analysis of the treatment potential of bioremediation technology to degrade eight major environmental pollutants, polycyclic aromatic hydrocarbons, phenols, pentachlorophenols, creosote, polychlorinated biphenyls, trichloroethylene, chlorobenzoates, and chlorophenols. The discussion includes information on transformation mechanisms, identification of intermediate metabolites, elucidation of partial or complete pathways, effects of environmental parameters, as well as current and future industrial application.

Results indicate that bioremediation used in conjunction with other physical and chemical treatment methodologies can effectively transform most prevalent nonchlorinated organic contaminants and some chlorinated contaminants, such as creosote and pentachlorophenol, into innocuous materials. Successful biodegradation of several other chlorinated organic compounds, notably polychlorinated biphenyls and trichloroethylene, is currently possible only under controlled laboratory conditions. Future successful field applications, however, appear promising.