bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics and mechanism of addition of parabanic acid (imidazolidine‐2,4,5‐trione) to oxiranes
Authors: Zarzyka‐Niemiec Iwona , Lubczak Jacek 
Published: December 2002

AbstractThe results of studies on the kinetics of reaction of 1 mol of parabanic acid (imidazolidine‐2,4,5‐trione) with 1 mol of ethylene oxide (oxirane) or propylene oxide (2‐methyloxirane) carried out in the presence of triethylamine catalyst in dimethylsulfoxide solution are presented. A rate equation describing the reaction is presented and the mechanism proposed. The validity of the proposed mechanism is proved by instrumental analytical methods. The effect of temperature is also presented and the thermodynamic parameters of the reaction evaluated. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 73–80, 2003
Nonequilibrium solvent polarization in kinetics of SN2 reactions
Authors: Jaworski J. S. 
Published: December 2002

AbstractThe solvent effect on the experimental activation barriers for the reactions of methyl iodide with chloride and thiocyanate ions was analyzed according to the Marcus and Shaik theories, considering SN2 mechanism in terms of a single electron shift. The linear increase in the solvent reorganization energy of the Marcus theory (after removing contributions from the specific solvation) with the solvent Pekar factor, describing the effect of the nonequilibrium solvent polarization, was observed for six aprotic solvents. The direct support of the title effect based on the Shaik theory was less evident; however, in general, the calculated activation barriers in 10 solvents change parallel with the experimental ones. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 61–66, 2003
Relative rate constants for the reactions of hydroxyl radicals and chlorine atoms with a series of aliphatic alcohols
Authors: Wu Hai , Mu Yujing , Zhang Xiaoshan , Jiang Guibin 
Published: December 2002

AbstractRate constants for the gas‐phase reactions of hydroxyl radicals and chlorine atoms with a series of alcohols have been determined by using the relative method. The experiments were performed at 295 ± 2 K and at 1 atmospheric pressure. The obtained values of the rate constants in units of 10−12 cm3 molecule−1 s−1 are as follows:

Alcohol
Rate Constants for OH with
Rate Constants for Cl with

Propane
Cyclohexane
Propane
Cyclohexane

Ethyl alcohol
3.40 ± 0.25
–
103 ± 4
96 ± 7

n‐Propyl alcohol
5.47 ± 0.44
–
153 ± 13
147 ± 11

Isopropyl alcohol
5.31 ± 0.39
–
73.5 ± 3.7
82.7 ± 7.4

n‐Butyl alcohol
8.66 ± 0.66
–
211 ± 11
223 ± 10

Isobutyl alcohol
9.08 ± 0.35
9.59 ± 0.45
182 ± 4
196 ± 11

tert‐Butyl alcohol
1.11 ± 0.07
–
31.5 ± 2.4
34.1 ± 2.5

n‐Pentyl alcohol
12.2 ± 1.0
12.4 ± 0.5
257 ± 25
258 ± 12

Isopentyl alcohol
13.8 ± 0.5
13.2 ± 1.1
237 ± 7
235 ± 9

The above relative rate constants are based on the values (in units of 10−12 cm3 molecule−1 s−1) of k(OH + propane) = 1.08, k(OH + cyclohexane) = 7.22, k(Cl + propane) = 131 and k(Cl + cyclohexane) = 307. The results are compared with previous determinations. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 81–87, 2003
Revegetation of mining spoils by seeding of woody species on Ghiona Mountain, central Greece
Authors: Brofas G. , Karetsos G. 
Published: December 2002

AbstractThe reforestation potential of calcareous bauxite mining spoils by seeding was examined on experimental plot established at Strofi Koukouvista 5, Mount Ghiona in Central Greece. The experiment consists of three species (Pinus nigra, Robinia pseudoacacia, and Spartium junceum) with four sowing treatments and two sowing seasons (autumn and spring). The treatments were: broadcasting (B); broadcasting and soil cultivation (BC); broadcasting with straw mulching and straw binding with asphalt emulsion (BM); broadcasting with soil cultivation, straw mulching and straw binding with asphalt emulsion (BCM). In all cases sowing in spring was better than in autumn. Only Spartium junceum has germinated and survived in autumn, but less than in spring. The most effective treatments for Robinia pseudoacacia and Pinus nigra are BM and BCM while for Spartium junceum even simple broadcasting shows good results although the best are achieved with treatments BC, BM and BCM. The findings show that reforestation by sowing could be effective for some species, but further experimentation with other species and methods is recommended. Copyright © 2002 John Wiley & Sons, Ltd.
Soil carbon sequestration in China through agricultural intensification, and restoration of degraded and desertified ecosystems
Authors: Lal R. 
Published: December 2002

AbstractThe industrial emission of carbon (C) in China in 2000 was about 1 Pg yr−1, which may surpass that of the United States (1ċ84 Pg C) by 2020. China's large land area, similar in size to that of the United States, comprises 124 Mha of cropland, 400 Mha of grazing land and 134 Mha of forestland. Terrestrial C pool of China comprises about 35–60 Pg in the forest and 120–186 Pg in soils. Soil degradation is a major issue affecting 145 Mha by different degradative processes, of which 126 Mha are prone to accelerated soil erosion. Total annual loss by erosion is estimated at 5ċ5 Pg of soil and 15ċ9 Tg of soil organic carbon (SOC). Erosion‐induced emission of C into the atmosphere may be 32–64 Tg yr−1. The SOC pool progressively declined from the 1930s to 1980s in soils of northern China and slightly increased in those of southern China because of change in land use. Management practices that lead to depletion of the SOC stock are cultivation of upland soils, negative nutrient balance in cropland, residue removal, and soil degradation by accelerated soil erosion and salinization and the like. Agricultural practices that enhance the SOC stock include conversion of upland to rice paddies, integrated nutrient management based on liberal use of biosolids and compost, crop rotations that return large quantities of biomass, and conservation‐effective systems. Adoption of recommended management practices can increase SOC concentration in puddled soil, red soil, loess soils, and salt‐affected soils. In addition, soil restoration has a potential to sequester SOC. Total potential of soil C sequestration in China is 105–198 Tg C yr−1 of SOC and 7–138 Tg C yr−1 for soil inorganic carbon (SIC). The accumulative potential of soil C sequestration of 11 Pg at an average rate of 224 Tg yr−1 may be realized by 2050. Soil C sequestration potential can offset about 20 per cent of the annual industrial emissions in China. Copyright © 2002 John Wiley & Sons, Ltd.
Land degradation is contextual
Authors: Warren A. 
Published: December 2002

AbstractLand degradation cannot be judged independently of its spatial, temporal, economic, environmental and cultural context. Evaluations are therefore almost infinitely variable and very dynamic. These observations are examined in two contexts, first in two case studies. One, from the southern Levant, makes use of a long and well‐documented history of environmental assessment that varied greatly between communities. The other, from contemporary Niger, shows finer scale differences among villagers. Second, the dynamic and multiple assessment of futures (sustainability) is illustrated with data from the same case study in Niger. In this wider context, multiplicity and dynamicity are largely a consequence of the choice of model of the environmental or social future. The usually positive difference between large‐scale and finer scale assessments of degradation is dubbed the [social delivery ratio]. Simplified systems of evaluation may be necessary for allocation, but they need to be treated with great caution if the argument here is accepted. Copyright © 2002 John Wiley & Sons, Ltd.
Farmland degradation in the mountains of Nepal: a study of watersheds ‘with’ and ‘without’ external intervention
Authors: Thapa G. B. , Paudel G. S. 
Published: December 2002

AbstractAmidst growing concerns about farmlands conservation, this paper examines the status of farmlands in two mountain watersheds ‘with’ and ‘without’ external intervention, located in the western hills of Nepal. Information was obtained from a household survey and group discussions conducted during April to September 1999. The severity of soil erosion from farmers' perspectives, density of landslides, soil nutrient balance and change in crop yield have been adopted as indicators of the status of the land. Results of the analysis indicate that land resources in both watersheds are undergoing degradation, though the causes and extent of degradation vary from one type of land to another. Upland crop terraces, locally called bari, are undergoing degradation most seriously under the combined influence of severe soil erosion, landslide and the depletion of soil nutrients. In particular, soil erosion has severely affected nearly half of the upland crop terraces in both watersheds due to a number of natural and anthropogenic factors ranging from weak geological structure to arable agriculture. Landslide and nutrient depletion have affected all types of farmlands except homesteads in both watersheds. Overall, the extent and intensity of land degradation is relatively high in the non‐project area, as farmers were not provided with necessary technical and financial support. A broad strategy has been outlined for effective conservation of farmlands. Copyright © 2002 John Wiley & Sons, Ltd.
Land‐use change in two Nepalese watersheds: GIS and geomorphometric analysis
Authors: Awasthi K. D. , Sitaula B. K. , Singh B. R. , Bajacharaya R. M. 
Published: December 2002

AbstractAccurate measurement of land‐use/land‐cover and geomorphometric parameters is important for evaluating watershed conditions, yet these are surprisingly difficult quantities to measure accurately over large areas. Watershed analysis based on the geographic information system (GIS) was carried out in two watersheds in the western development region of Nepal. Land‐use maps were prepared after interpretation of 1978 and 1996 aerial photographs. Digital data for deriving geomorphometric parameters were prepared from topographical maps of scale 1: 25 000. The dynamics of land‐use and land‐cover change within the Mardi and Fewa watersheds were investigated by performing spatial analysis of digital land‐use maps in ArcView 3.1 desktop environment. There was a net increase in forest cover of 2ċ4 per cent and 1ċ1 per cent in the Mardi and Fewa watersheds respectively, with a corresponding decrease in shrub and rainfed agriculture. Land use was found to be highly dynamic with significant internal trading among the land‐use classes. A significant area under agriculture in 1978 was found abandoned in 1996 in both watersheds most likely due to increased out migration of the labour force. Geomorphometric parameters such as hypsometric curves, hypsometric integrals (HI), drainage density and length of overland flow were analysed to explain the watershed conditions. The results of geomorphometric analysis revealed that the watersheds have been subjected in the past to high erosion and are still susceptible to lateral surface erosion hence soil degradation. Some suggestion for management can be derived from this study. Copyright © 2002 John Wiley & Sons, Ltd.
Aggregates stability and water erosion in Andosols of the Canary Islands
Authors: Rodríguez Rodríguez A. , Guerra J. A. , Gorrín S. P. , Arbelo C. D. , Mora J. L. 
Published: December 2002

AbstractThe aim of this paper is to assess the mechanisms of water erosion in andic soils using two tests, which in a certain way simulate the two principal mechanisms of aggregate destruction in the process of water erosion—water dispersion and raindrops impact—and compare them with the aggregation observed in material dettached by inter‐rill erosion (sediments) in experimental plots with natural rain. In accordance with the obtained results, the erosive process in these soils seems to come about through a picking off of surface material of larger aggregates, due to the impact of raindrops. The intensity of pull off and fragment size from larger aggregates depends on the kinetic energy of the drops (rain intensity), but the size generally ranges between 0ċ2 and 0ċ5 mm. Therefore inter‐rill erosion initially proceeds by a washing down of smaller aggregates (<0ċ5 mm) (of less bulk density than larger aggregates 0ċ4 Mg m−3 against 0ċ9 Mg m−3), enriching the soil in larger sized aggregates which, on being fragmented by picking off of raindrops, supply new material for washing down by inter‐rill erosion. Copyright © 2002 John Wiley & Sons, Ltd.
Uniform corrosion of titanium in alkaline hydrogen peroxide conditions: influence of transition metals and inhibitors calcium and silicate
Authors: Rämö J. , Saarinen K. , Sillanpää M. 
Published: December 2002

AbstractUniform corrosion of titanium was studied in alkaline hydrogen peroxide environments simulating pulp bleaching conditions. Corrosion rates of unalloyed Grade 2 and alloyed Grade 5 were determined as a function of hydrogen peroxide anion (HOO−) concentration. Influences of calcium and silicate inhibitors and iron and manganese were investigated. Without inhibition titanium corroded at HOO− content of 200 mg/l: Grade 2 0.4 mm/y and Grade 5 1.4 mm/y. Addition of calcium (Ca2+) and silicate (SiO32−) diminished the corrosion of Grade 2 to critical anion level 400 mg/l, but could not protect Grade 5 even at the HOO− concentration of 300 mg/l. Presence of iron and manganese raised the critical levels of the both grades. High HOO− anion level was observed as a notable potential difference between titanium and platinum.
Adaptive crack propagation analysis with the element‐free Galerkin method
Authors: Lee Gye‐Hee , Chung Heung‐Jin , Choi Chang‐Koon 
Published: December 2002

AbstractIn this paper, an adaptive analysis of crack propagation based on the error estimation by the element‐free Galerkin (EFG) method is presented. The adaptivity analysis in quasi‐static crack propagation is achieved by adding and/or removing the nodes along the background integration cells, those are refined or recovered according to the estimated errors. These errors are obtained basically by calculating the difference between the values of the projected stresses and original EFG stresses. To evaluate the performance of the proposed adaptive procedure, the crack propagation behaviour is investigated for several examples. The results of these examples show the efficiency and accuracy of the proposed scheme in crack propagation analysis. Copyright © 2002 John Wiley & Sons, Ltd.
Thermoelastic stress field in a piecewise homogeneous domain under non‐uniform temperature using a coupled boundary and finite element method
Authors: Guven I. , Madenci E. 
Published: December 2002

AbstractThis study concerns the development of a coupled finite element–boundary element analysis method for the solution of thermoelastic stresses in a domain composed of dissimilar materials with geometric discontinuities. The continuity of displacement and traction components is enforced directly along the interfaces between different material regions of the domain. The presence of material and geometric discontinuities are included in the formulation explicitly. The unknown interface traction components are expressed in terms of unknown interface displacement components by using the boundary element method for each material region of the domain. Enforcing the continuity conditions leads to a final system of equations containing unknown interface displacement components only. With the solution of interface displacement components, each region has a complete set of boundary conditions, thus leading to the solution of the remaining unknown boundary quantities. The concepts developed for the BEM formulation of a domain with dissimilar regions is employed in the finite element–boundary element coupling procedure. Along the common boundaries of FEM–BEM regions, stresses from specific BEM regions are first expressed in terms of interface displacements, then integrated and lumped at the nodal points of the common FEM–BEM boundary so that they are treated as boundary conditions in the analysis of FEM regions along the common FEM–BEM boundary. Copyright © 2002 John Wiley & Sons, Ltd.
Transient heat conduction analysis in a piecewise homogeneous domain by a coupled boundary and finite element method
Authors: Guven I. , Madenci E. 
Published: December 2002

AbstractA coupled finite element–boundary element analysis method for the solution of transient two‐dimensional heat conduction equations involving dissimilar materials and geometric discontinuities is developed. Along the interfaces between different material regions of the domain, temperature continuity and energy balance are enforced directly. Also, a special algorithm is implemented in the boundary element method (BEM) to treat the existence of corners of arbitrary angles along the boundary of the domain.Unknown interface fluxes are expressed in terms of unknown interface temperatures by using the boundary element method for each material region of the domain. Energy balance and temperature continuity are used for the solution of unknown interface temperatures leading to a complete set of boundary conditions in each region, thus allowing the solution of the remaining unknown boundary quantities.The concepts developed for the BEM formulation of a domain with dissimilar regions is employed in the finite element–boundary element coupling procedure. Along the common boundaries of FEM–BEM regions, fluxes from specific BEM regions are expressed in terms of common boundary (interface) temperatures, then integrated and lumped at the nodal points of the common FEM–BEM boundary so that they are treated as boundary conditions in the analysis of finite element method (FEM) regions along the common FEM–BEM boundary. Copyright © 2002 John Wiley & Sons, Ltd.
Imposition of boundary conditions by modifying the weighting coefficient matrices in the differential quadrature method
Authors: Fung T. C. 
Published: December 2002

AbstractOne of the important issues in the implementation of the differential quadrature method is the imposition of the given boundary conditions. There may be multiple boundary conditions involving higher‐order derivatives at the boundary points. The boundary conditions can be imposed by modifying the weighting coefficient matrices directly. However, the existing method is not robust and is known to have many limitations. In this paper, a systematic procedure is proposed to construct the modified weighting coefficient matrices to overcome these limitations. The given boundary conditions are imposed exactly. Furthermore, it is found that the numerical results depend only on those sampling grid points where the differential quadrature analogous equations of the governing differential equations are established. The other sampling grid points with no associated boundary conditions are not essential. Copyright © 2002 John Wiley & Sons, Ltd.
Minimum weight design of non‐linear elastic structures with multimodal buckling constraints
Authors: Trentadue Francesco 
Published: December 2002

AbstractIt well known that multimodal instability is an event particularly relevant in structural optimization. Here, in the context of non‐linear stability theory, an exact method is developed for minimum weight design of elastic structures with multimodal buckling constraints. Given an initial design, the method generates a sequence of improved designs by determining a sequence of critical equilibrium points related to decreasing values of the structural weight. Multimodal buckling constraints are imposed without repeatedly solving an eigenvalue problem, and the difficulties related to the non‐differentiability in the common sense of state variables in multimodal critical states, are overcome by means of the Lagrange multiplier method. Further constraints impose that only the first critical equilibrium states (local maxima or bifurcation points) on the initial equilibrium path of the actual designs are taken into account. Copyright © 2002 John Wiley & Sons, Ltd.
Finite element computation of sloshing modes in containers with elastic baffle plates
Authors: Bermúdez Alfredo , Rodríguez Rodolfo , Santamarina Duarte 
Published: December 2002

AbstractA finite element method to approximate the vibration modes of a plate in contact with an incompressible fluid is analysed in this paper.The effect of the fluid is taken into account by means of an added mass formulation, discretized by standard piecewise linear tetrahedral finite elements. Gravity waves on the free surface of the liquid are considered in the model. The plate is modelled by Reissner–Mindlin equations discretized by MITC3 locking‐free elements.Implementation issues are discussed and numerical experiments are presented. In particular, the method is compared with analytical approximations and with an experimental study which has been recently reported. Copyright © 2002 John Wiley & Sons, Ltd.
Two trigonometric quadrature formulae for evaluating hypersingular integrals
Authors: Kim Philsu , Choi U. Jin 
Published: December 2002

AbstractTwo trigonometric quadrature formulae, one of non‐interpolatory type and one of interpolatory type for computing the hypersingular integral ${\int\hskip-0.33cm=}_{-1}^{1} w(\tau)g(\tau)/(\tau-t)^{2} \,{\rm d}\tau$ are developed on the basis of trigonometric quadrature formulae for Cauchy principal value integrals. The formulae use the cosine change of variables and trigonometric polynomial interpolation at the practical abscissae. Fast three‐term recurrence relations for evaluating the quadrature weights are derived. Numerical tests are carried out using the current formula. As applications, two simple crack problems are considered. One is a semi‐infinite plane containing an internal crack perpendicular to its boundary and the other is a centre cracked panel subjected to both normal and shear tractions. It is found that the present method generally gives superior results. Copyright © 2002 John Wiley & Sons, Ltd.
Lessons learned from a small native American community
Authors: Espeland Wendy Nelson 
Published: December 2002

AbstractThe decision not to build Orme Dam was a great political victory for residents of the Fort McDowell Indian Reservation in central Arizona. This article examines the conditions that gave rise to what most considered an unlikely outcome, and the lessons it suggests for understanding the politics of large water projects. These lessons include the importance of understanding that rationality takes multiple forms; that how value is expressed can be as significant as what, and how much, something is valued; that identity politics which elaborates and celebrates cultural differences can be an effective means for challenging even powerful bureaucracies; and that law can be an important mediating structure in the politics of bureaucratic decision‐making. Copyright © 2002 John Wiley & Sons, Ltd.
Popular mobilization and disaster management in Cuba
Authors: Sims Holly , Vogelmann Kevin 
Published: December 2002

AbstractCuba has effectively implemented a system of popular mobilization and education to prepare people for such natural disasters as hurricanes. Compliance with evacuation orders is impressive. Top priority is attached to saving lives. The country's acclaimed programme accounts for the limited toll of Hurricane Michelle in November 2001, which was the most powerful storm since 1944. Five Cubans died in the storm, which wreaked havoc in Jamaica, Honduras, and Nicaragua. This article reviews recent Cuban experience in disaster preparedness, which was achieved despite material scarcity. Since the prestigious Intergovernmental Panel on Climate Change warns of increased susceptibility to disasters in future, Cuba's record deserves wide attention. Copyright © 2002 John Wiley & Sons, Ltd.