Search results for "Bulk"
showing 10 items of 286 documents
Using a transient infiltrometric technique for intensively sampling field-saturated hydraulic conductivity of a clay soil in two runoff plots
2012
The point measurement of soil properties allows to explain and simulate plot scale hydrological processes. An intensive sampling was carried out at the surface of an unsaturated clay soil to measure, on two adjacent plots of 4 × 11 m2 and two different dates (May 2007 and February–March 2008), dry soil bulk density, ρb, and antecedent soil water content, θi, at 88 points. Field-saturated soil hydraulic conductivity, Kfs, was also measured at 176 points by the transient Simplified Falling Head technique to determine the soil water permeability characteristics at the beginning of a possible rainfall event yielding measurable runoff. The ρb values did not differ significantly between the two d…
Soil physical quality changes under different management systems after 10 years in the Argentine humid pampa
2015
Abstract. South American countries with the highest surface of land under no-tillage (NT) management are Brazil, Argentina and Chile. In Argentina, 78.5% of the agricultural land is cropped under NT management. Several experiments have confirmed the improvements in soil aggregation and infiltration achieved by NT management in dry-land farming areas associated with increases of bulk density (δb) under NT management. An increase in bulk density implies a reduction of the macro and mesoporosity that is in contradiction with the increased infiltration that occurs at macro and mesopores. We hypothesize that the increase of bulk density in NT management mainly affects the mesopores. We evaluated…
The impact of road and railway embankments on runoff and soil erosion in eastern Spain
2015
Abstract. Road and railway infrastructure increased in the Mediterranean region during the last three decades. This included the building of embankments, which are assumed to be a~large source of sediments and runoff. However, little is known about soil erosion rates, the factors that control them, and the processes that contribute to detachment, transport and deposition of sediments from road and railway embankments. The objective of this study was therefore to assess the impacts of road and railway embankments as a source of sediment and water, and compare them to other land use types (citrus plantations and shrublands) representative of the Cànyoles watershed to evaluate the importance o…
LOCAL MICROWAVE HYPERTHERMIA AND INTRAVESICAL CHEMOTHERAPY AS BLADDER SPARING TREATMENT FOR SELECT MULTIFOCAL AND UNRESECTABLE SUPERFICIAL BLADDER TU…
1998
Purpose: The role of a combined regimen of local hyperthermia and topical chemotherapy in patients with multifocal and recurrent superficial bladder tumors not curable by transurethral resection was evaluated in a neodjuvant organ sparing clinical study. Materials and Methods: A total of 19 patients with multifocal, superficial grades 1 to 3 bladder tumors that recurred after intravesical chemoprophylaxis or immunoprophylaxis underwent local combined administration of microwave induced hyperthermia and intravesical chemotherapy as a debulking approach. Due to extensive superficial involvement of the bladder walls complete transurethral resection of all tumors seemed technically unfeasible i…
Appendix – Additional Measurements
2016
This appendix deals with the determination of different soil physical and hydraulic characteristics used in the analysis and/or interpretation of the infiltration experiments. The core method and the excavation method for measurement of soil bulk density are initially presented. Determination of soil water content by the thermo-gravimetric and the Time Domain Reflectometry methods is then illustrated. Subsequently, field measurement of soil water matric potential by tensiometers is discussed. Laboratory determination of the soil water retention curve by tensiometric and pressiometric techniques is also described. Finally, different methods to test water stability of soil aggregates are illu…
Vibrational Sum Frequency Generation Spectroscopy of the Water Liquid–Vapor Interface from Density Functional Theory-Based Molecular Dynamics Simulat…
2013
International audience; The vibrational sum frequency generation (VSFG) spectrum of the water liquid-vapor (LV) interface is calculated using density functional theory-based molecular dynamics simulations. The real and imaginary parts of the spectrum are in good agreement with the experimental data, and we provide an assignment of the SFG bands according to the dipole orientation of the interfacial water molecules. We use an instantaneous definition of the surface, which is more adapted to the study of interfacial phenomena than the Gibbs dividing surface. By calculating the vibrational (infrared, Raman) properties for interfaces of varying thickness, we show that the bulk spectra signature…
Pressure Effect Investigations on the Spin Crossover Systems{Fe[H 2 B(pz) 2 ] 2 (bipy)} and {Fe[H 2 B(pz) 2 ] 2 (phen)}
2006
Pressure effect studies on the spin crossover behaviour of the mononuclear compounds {Fe[H2B(pz)2]2(bipy)}(1) and {Fe[H2B(pz)2]2(phen)}(2) have been performed in the range of 105 Pa–1.02 GPa at variable temperatures (100–310 K). Continuous spin transitions and displacement of its characteristic temperature has been observed for 1 with increasing pressure. Meanwhile the response of 2 under applied pressures is quite unexpected, and can only be understood in terms of a crystallographic phase transition or change in the bulk modulus of the compound. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Comparative Study of the Compressibility of M3V2O8 (M = Cd, Zn, Mg, Ni) Orthovanadates
2022
We report herein a theoretical study of the high-pressure compressibility of Cd3V2O8, Zn3V2O8, Mg3V2O8, and Ni3V2O8. For Cd3V2O8, we also present a study of its structural stability. Computer simulations were performed by means of first-principles methods using the CRYSTAL program. In Cd3V2O8, we found a previously unreported polymorph which is thermodynamically more stable than the already known polymorph. We also determined the compressibility of all compounds and evaluated the different contributions of polyhedral units to compressibility. We found that the studied vanadates have an anisotropic response to compression and that the change in volume is basically determined by the compressi…
Compressibility and Structural Stability of Nanocrystalline TiO2 Anatase Synthesized from Freeze-Dried Precursors
2014
The high-pressure structural behavior of 30 nm nanoparticles of anatase TiO2 was studied under hydrostatic and quasi-hydrostatic conditions up to 25 GPa. We found that the structural sequence is not sensitive to the use of different pressure transmitting media. Anatase-type nanoparticles exhibit a phase transition beyond 12 GPa toward a baddeleyite-type structure. Under decompression this phase transition is irreversible, and a metastable columbite-type structure is recovered at ambient conditions. The bulk modulus of anatase-type nanoparticles was determined confirming that nanoparticles of TiO2 are more compressible than bulk TiO2. Similar conclusions were obtained after the determination…
Carbanionic Polymerization: Kinetics and Thermodynamics
1989
For a kinetic analysis, the process of anionic polymerization has to be divided into at least three main reactions common to all types of polymerization (equations 1–3). I* denotes initiator, M monomer, Pi* and Pi′ an active or inactive polymer chain of degree of polymerization i, respectively, and X a terminating agent.