Remediation of Expansive Soils Using Agricultural Waste Bagasse Ash

© 2016 The Authors. Published by Elsevier B.V. Bagasse is a fibrous material remaining after crushing sugarcane to extract its juice; and bagasse ash is produced after burning bagasse. Improper disposal of this material can create environmental problems around sugar manufacturing plants. Bagasse ash, comprising a high percentage of silica (SiO2), is considered as a sensible pozzolanic material with non-reactive behaviour and has potential to be used in road subgrade stabilisation. One of the main challenges for transportation organisations in Australia is to treat subgrades including expansive soils. Expansive soils exhibit significant movements when the moisture content changes, and hence it causes substantial damage to road pavements constructed over these type of soils. Road engineers need to employ materials having acceptable strength, relatively low price and being eco-friendly. In order to demonstrate the potential ability of bagasse ash in curtailing the adverse effects of expansive soils on roads, an array of experimental tests using bagasse ash have been conducted. In this study to activate and improve the effectiveness of bagasse ash, hydrated lime was used and mixed with black soil samples, collected from Queensland Australia. Samples were prepared using different contents of bagasse ash and hydrated lime (0%, 6%, 10%, 18% and 25% by the dry mass of soil), at a ratio of 3:1, respectively. The results of free swell ratio (FSR) test, unconfined compression strength (UCS) and California bearing ratio (CBR) tests are presented for untreated and treated samples after various curing time periods of 3, 7 and 28 days. The outcomes of these tests clearly demonstrate that stabilisation of expansive soils using bagasse ash and hydrated lime not only improves the strength, but also facilitates to cope with environmental concerns through reduction of sugar industry waste material

Analysis of pore-fluid pressure gradient and effective vertical-stress gradient distribution in layered hydrodynamic systems

A theoretical analysis is carried out to investigate the pore-fluid pressure gradient and effective vertical-stress gradient distribution in fluid saturated porous rock masses in layered hydrodynamic systems. Three important concepts, namely the critical porosity of a porous medium, the intrinsic Fore-fluid pressure and the intrinsic effective vertical stress of the solid matrix, are presented and discussed. Using some basic scientific principles, we derive analytical solutions and explore the conditions under which either the intrinsic pore-fluid pressure gradient or the intrinsic effective vertical-stress gradient can be maintained at the value of the lithostatic pressure gradient. Even though the intrinsic pore-fluid pressure gradient can be maintained at the value of the lithostatic pressure gradient in a single layer, it is impossible to maintain it at this value in all layers in a layered hydrodynamic system, unless all layers have the same permeability and porosity simultaneously. However, the intrinsic effective vertical-stress gradient of the solid matrix can be maintained at a value close to the lithostatic pressure gradient in all layers in any layered hydrodynamic system within the scope of this study

Pengaruh Kompetensi Sumber Daya Manusia dan Pemanfaatan Teknologi Informasi terhadap Kualitas Penyajian Laporan Keuangan

This research intended to explore the effect of the competence of human resource and the use of technology information to financial report quality. The object of this research was SKPD Government of Empat Lawang Regency of South Sumatera Province. Sample in the research amounted to 39 samples of employees. The results showed that the competence of human resources significantly positive impact on the quality of financial statement presentation. While on the utilization of information technology had no significant effect. By adding financial accountability as a moderator variable, the R Square competency variable of human resources rose by 0.203 or 20.3%. Then on variable utilization of information technology equal to 0,140 or 14%. It could be concluded that with the existence of financial accountability would be able to strengthen the relationship between the competence of human resources and utilization of information technology to the quality of financial presentation

Finite driving rate and anisotropy effects in landslide modeling

In order to characterize landslide frequency-size distributions and individuate hazard scenarios and their possible precursors, we investigate a cellular automaton where the effects of a finite driving rate and the anisotropy are taken into account. The model is able to reproduce observed features of landslide events, such as power-law distributions, as experimentally reported. We analyze the key role of the driving rate and show that, as it is increased, a crossover from power-law to non power-law behaviors occurs. Finally, a systematic investigation of the model on varying its anisotropy factors is performed and the full diagram of its dynamical behaviors is presented.Comment: 8 pages, 9 figure

Single-Grain Virtualization for Contact Behavior Analysis on Sand

A methodology for virtualizing irregularly shaped grains is described here. The principle, largely inspired by computed tomography, is simple and accessible because only the three-dimensional (3D) outline of the grain is required. The volumetric object is obtained by reconstructing the planar projections of the grain acquired at different angles of rotation using a standard camera. Depending on the lens system, the resolution of the images can be as good as a few microns. A numerical representation of the real grain can be obtained by meshing the 3D image. The influence of grain morphology on the contact behavior of quartz sand is investigated here as an application of this novel technique. Numerical simulations using a finite-element model were carried out to reproduce the experimental data from normal compression single-grain tests. The results show the contribution of the initial grain rearrangement on the normal force-displacement response and its strong dependency on the shape of the grain. This study demonstrates that particle shape is a critical parameter for calibration of the contact behavior of sand

Absence of a dose-rate effect in the transformation of C3H 10T1/2 cells by α-particles

The findings of Hill et al. (1984) on the greatly enhanced transformation frequencies at very low dose rates of fission neutrons induced us to perform an analogous study with -particles at comparable dose rates. Transformation frequencies were determined with γ-rays at high dose rate (0·5 Gy/min), and with -particles at high (0·2 Gy/min) and at low dose rates (0·83-2·5 mGy/min) in the C3H 10T1/2 cell system. α-particles were substantially more effective than γ-rays, both for cell inactivation and for neoplastic transformation at high and low dose rates. The relative biological effectiveness (RBE) for cell inactivation and for neoplastic transformation was of similar magnitude, and ranged from about 3 at an -particle dose of 2 Gy to values of the order of 10 at 0·25 Gy. In contrast to the experiments of Hill et al. (1984) with fission neutrons, no increased transformation frequencies were observed when the -particle dose was protracted over several hours

Sediment compaction rates and subsidence in deltaic plains : numerical constraints and stratigraphic influences

This paper is not subject to U.S. copyright. The definitive version was published in Basin Research 19 (2007): 19-31, doi:10.1111/j.1365-2117.2006.00310.x.Natural sediment compaction in deltaic plains influences subsidence rates and the evolution of deltaic morphology. Determining compaction rates requires detailed knowledge of subsurface geotechnical properties and depositional history, neither of which is often readily available. To overcome this lack of knowledge, we numerically forward model the incremental sedimentation and compaction of stochastically generated stratigraphies with geotechnical properties typical of modern depositional environments in the Mississippi River delta plain. Using a Monte Carlo approach, the range of probable compaction rates for stratigraphies with compacted thicknesses <150 m and accumulation times <20 kyr. varies, but maximum values rarely exceed a few mm yr-1. The fastest compacting stratigraphies are composed primarily of peat and bar sand, whereas the slowest compacting stratigraphies are composed of prodelta mud and natural levee deposits. These results suggest that compaction rates can significantly influence vertical and lateral stratigraphic trends during deltaic evolution