Fractal fragmentation of rocks within sturzstroms: insight derived from physical experiments within the ETH geotechnical drum centrifuge

An investigation of the behaviour and energy budget of sturzstroms has been carried out using physical, analytical and numerical modelling techniques. Sturzstroms are rock slides of very large volume and extreme run out, which display intensive fragmentation of blocks of rock due to inter-particle collisions within a collisional flow. Results from centrifugal model experiments provide strong arguments to allow the micro-mechanics and energy budget of sturzstroms to be described quantitatively by a fractal comminution model. A numerical experiment using a distinct element method (DEM) indicates rock mass and boundary conditions, which allow an alternating fragmenting and dilating dispersive regime to evolve and to sustain for long enough to replicate the spreading and run out of sturzstroms without needing to resort to peculiar mechanism. The fragmenting spreading model supported here is able to explain the run out of a fluid-absent granular flow beyond the travel distance predicted by a Coulomb frictional sliding model. This, and its strong relation to internal fragmentation, suggests that a sturzstrom constitutes a landslide category of its own. This study provides a novel framework for the understanding the physics of such sturzstrom

Construction of Motorway on Double Porosity Clay Fill

The paper describes the mechanical behaviour of double porosity clay fills. A trial embankment had been constructed on a 20-30 year-old landfill and monitored for 3 years. The embankment was instrumented by hydrostatic levelling profiles, surveying reference points, pore pressure gauges, inclinometers and depth reference points. Centrifuge modelling of the embankment behaviour on the consolidated landfill was carried out in the geotechnical centrifuge at ETH Zürich in Switzerland. The models were instrumented similarly to the real embankment with pore pressure transducers and a newly developed tool called “system of straws” for measurement of deformation at different depths. Surface deformations were measured by laser scanning. The results of centrifuge modelling are compared with in-situ data. The degradation of the double porosity structure in the vertical profile of the landfill, and its influence on the permeability of the soil is discussed

Study of Biomass Bottom Ash Efficiency as Phosphate Sorbent Material

Excessive richness of nutrients in water bodies such as rivers, lakes and ponds lead into deterioration of aquatic life as a results of dense growth of algae. Phosphate is one of the main nutrients that should be controlled to prevent this serious issue. Utilizing low cost material as a phosphate sorbent is offering a treatment method characterized as a sustainable solution. In this study the efficiency of biomass bottom ash BBA as phosphate sorbent material from aqueous solution is investigated. Batch experiments were undertaken, in which a particular mass of BBA was brought into contact with the phosphate solution. The experiments studied the influence of pH (different phosphate solutions were prepared with pH range 4 to 8), temperature (adsorption capacity measured at the temperature range of 10 to 30 °C), and contact time. In addition, the adsorption isotherm models were also applied to better understand the mechanism of phosphate sorption by BBA. The results revealed that the bonding between the cations (BBA surface) and anions (phosphate solution) is significantly affected by the pH of the solution. BBA presents an excellent phosphate sorption, especially, at low pH value and temperature around 20 oC. The method of this research can be adopted as a followed strategy for examination the capability of selected material for phosphorus removal from wastewater

Large-scale shear test of brash ice

A large-scale shear apparatus has been originally developed and built to test the mechanical properties of coarsegrained material. It was used to evaluate the shear behaviour of brash ice. The brash ice blocks were collected at Luleå harbour in two separate measuring campaigns in March 2020 and March 2021. The shear cylinder was loaded with brash ice in Luleå port in two different locations for the two test campaigns, and the displacementcontrolled shear tests were conducted. A vertical actuator was used to set a constant normal load and then a horizontal actuator was used to move the shear swing. In this setup, time, forces, and displacements were recorded at the forward and return stroke of the horizontal actuator. In total 6 shear cycles on two brash ice samples with axial stress of 4.8 kPa, 2 kPa and 1 kPa were performed. The test data was analysed to determine the relationship between shear stress and shear strain. The macro-porosity and confining axial force were found to be the most influential factors in determining the strength and deformation of the brash ice. Furthermore, an attempt has been made to estimate a few parameters of a material model known as the Continuous Surface Cap Model.publishedVersio

A software framework for analysing solid-state MAS NMR data

Solid-state magic-angle-spinning (MAS) NMR of proteins has undergone many rapid methodological developments in recent years, enabling detailed studies of protein structure, function and dynamics. Software development, however, has not kept pace with these advances and data analysis is mostly performed using tools developed for solution NMR which do not directly address solid-state specific issues. Here we present additions to the CcpNmr Analysis software package which enable easier identification of spinning side bands, straightforward analysis of double quantum spectra, automatic consideration of non-uniform labelling schemes, as well as extension of other existing features to the needs of solid-state MAS data. To underpin this, we have updated and extended the CCPN data model and experiment descriptions to include transfer types and nomenclature appropriate for solid-state NMR experiments, as well as a set of experiment prototypes covering the experiments commonly employed by solid-sate MAS protein NMR spectroscopists. This work not only improves solid-state MAS NMR data analysis but provides a platform for anyone who uses the CCPN data model for programming, data transfer, or data archival involving solid-state MAS NMR data

On a modified-Lorentz-transformation based gravity model confirming basic GRT experiments

Implementing Poincar\'e's `geometric conventionalism' a scalar Lorentz-covariant gravity model is obtained based on gravitationally modified Lorentz transformations (or GMLT). The modification essentially consists of an appropriate space-time and momentum-energy scaling ("normalization") relative to a nondynamical flat background geometry according to an isotropic, nonsingular gravitational `affecting' function Phi(r). Elimination of the gravitationally `unaffected' S_0 perspective by local composition of space-time GMLT recovers the local Minkowskian metric and thus preserves the invariance of the locally observed velocity of light. The associated energy-momentum GMLT provides a covariant Hamiltonian description for test particles and photons which, in a static gravitational field configuration, endorses the four `basic' experiments for testing General Relativity Theory: gravitational i) deflection of light, ii) precession of perihelia, iii) delay of radar echo, iv) shift of spectral lines. The model recovers the Lagrangian of the Lorentz-Poincar\'e gravity model by Torgny Sj\"odin and integrates elements of the precursor gravitational theories, with spatially Variable Speed of Light (VSL) by Einstein and Abraham, and gravitationally variable mass by Nordstr\"om.Comment: v1: 14 pages, extended version of conf. paper PIRT VIII, London, 2002. v2: section added on effective tensorial rank, references added, appendix added, WEP issue deleted, abstract and other parts rewritten, same results (to appear in Found. Phys.