In South Africa, a Land Type Survey (LTSS) has been conducted of the entire country. The information available from the LTSS is readily and inexpensively made available to the public (in the form of ...maps and accompanying memoirs). This survey includes information on the climate, terrain and soils. The soil information given includes qualitative data (such as pedological classifications, soil profiles and soil types), as well as quantitative physical and chemical properties of representative soils tested. Such information is used primarily for agricultural purposes. This paper proposes an approach for inferring information, of relevance in reconnaissance geotechnical engineering surveys, from Land Type data, to supplement geotechnical investigation data. The proposed procedure was verified using actual information from a geotechnical report. This investigation indicated that general engineering properties can be inferred from qualitative pedological data. In addition, statistically significant engineering properties (including the grading, Atterberg Limits and the USCS and AASHTO classifications) were determined from quantitative pedological data, in 86% of cases, for the soils considered. It is evident from this research that data from the Land Type survey data can be successfully used for geotechnical investigation purposes for certain developments (such as roads and townships) where the depth of interest is relatively shallow.
Various pedological soil classification systems exist worldwide, including an internationally accepted system and various national systems, many of which have been incorporated into databases that ...include maps. Various physical and chemical soil properties are used for classifying soils according to these pedological systems. This paper proposes an approach which may be used to determine the engineering properties of soils from the physical and chemical properties that are used to pedologically classify soils by systems, and, in particular, the South African Binomial System. These engineering properties include the USCS and AASHTO classification groups which may, in turn, be used as a means of rapidly determining the general suitability of areas for proposed development, particularly during the reconnaissance investigation stages of transportation route locations and township developments, with a resultant saving of time and money. The model was verified using data from the study area, as well as from an area located approximately 190 km from the study area. A total of 88% of the classification groups determined by the model, in the study area, were correct. Furthermore, only 6% of the classifications were incorrect by a maximum of two groups. The classifications determined for the soils outside the study area were all correct.
Knowledge of the physical properties of soils, including the clay content, is of utmost importance in the field of geotechnical engineering. The hydrometer analysis is the most widely used technique ...for the analysis of the particle size distribution of the fine-grained fraction of a soil, calculated using sedimentation principles. The hydrometer analysis utilises a dispersing agent - Calgon 33:7 (comprising 33 grams of sodium hexametaphosphate and 7 grams of sodium carbonate when mixed in 1 litre of water) is universally considered as the most effective dispersing agent. In this investigation, hydrometer analyses were conducted (according to the TMH1 1986 method) on two soils (alluvium and black clay), using five dispersing agents. The results show that the clay size fraction can vary significantly (from 1% to 32%) for the two soils, depending upon the dispersing agent used. From these initial results, the two most effective dispersing agents (Calgon and sodium pyrophosphate decahydrate - NaPP) were investigated further to establish the optimum concentration and volume. Calgon proved to be the most effective in the alluvial soil, increasing the clay content by 38%. The NaPP was most effective in the relatively active black soil, increasing the clay content by 25%.
Timing performance of a Micro-Channel-Plate Photomultiplier Tube Bortfeldt, J.; Brunbauer, F.; David, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Volume:
960, Issue:
C
Journal Article
Peer reviewed
Open access
The spatial dependence of the timing performance of the R3809U-50 Micro-Channel-Plate PMT (MCP-PMT) by Hamamatsu was studied in high energy muon beams. Particle position information is provided by a ...GEM tracker telescope, while timing is measured relative to a second MCP-PMT, identical in construction. In the inner part of the circular active area (radius r<5.5 mm) the time resolution of the two MCP-PMTs combined is better than 10 ps. The signal amplitude decreases in the outer region due to less light reaching the photocathode, resulting in a worse time resolution. The observed radial dependence is in quantitative agreement with a dedicated simulation. With this characterization, the suitability of MCP-PMTs as t0 reference detectors has been validated.
Neutron GEM-based detectors represent a new frontier of diagnostic devices in neutron-linked physics applications such as detectors for fusion experiments (Croci et al., 2012 1) and spallation ...sources (Murtas et al., 2012 2). Besides, detectors installed in HEP experiments (like LHC at CERN) are dip in a high flux neutron field. For example, the TOTEM T2 GEM telescope (Bagliesi et al., 2010 3) at LHC is currently installed very close to the beam pipe where a high intensity (>104ncm−2s−1) neutron background is present. In order to assess the capability (particularly related to discharge probability) of working in intense neutrons environment, a 10×10cm2 Triple GEM detector has been tested using a high flux (105ncm−2s−1) neutron beam. The neutron-induced discharge probability PDisch was measured to be 1.37×10−7 at an effective gain G=5×104. In addition, the different types of neutron interactions within the detector were fully explained through a GEANT4 simulation.
The Astroneu array consists of three autonomous Extensive Air Shower (EAS) detection stations installed and operated at the Hellenic Open University campus. Each station (Astroneu station) combines ...two different detection technologies. Three charged particle detectors arranged in a triangle and an RF antenna in the middle. Before installation several calibration procedures were performed both to the individual detectors of the array as well as to each integrated Astroneu station. In this paper we present the development of simulation methods, data analysis techniques and experimental procedures, which have been used to calibrate and optimize the operating parameters of the Astroneu particle detectors, to process the experimental signals and extract timing and amplitude information, to correct for systematic biases and estimate precisely the particle-front arrival time on each individual detector resulting to accurate reconstruction of the detected EAS direction. Furthermore, the performance of the Astroneu telescope in detecting and reconstructing EAS is demonstrated with special inter-calibration runs, where pairs of stations are detecting simultaneously the same air shower, as well as with comparisons against the predictions of a detailed simulation description of the detectors.
Studies on the modification of the hydration products of fly ash (FA),
β-
cyclodextrin (
β
-CD) and fly ash-
β-
cyclodextrin (FA-
β
-CD) composite cement paste samples as hydration progressed were ...done using X-ray diffraction analysis, scanning electron microscopy and Fourier transform infrared spectroscopy. This paper investigates the effect of FA,
β
-CD and FA-
β-
CD composite on the hydration and pozzolanic reactions. It was evident from all the analyses that
β
-CD improved the hydration reaction from the 7 day hydration period, while improvement on pozzolanic reaction was revealed from the 28 day hydration period. The study contributed to the knowledge of FA performance as a composite with cyclodextrin and promoted the continued inclusion of FA in concrete.
The Hellenic Open University Cosmic Ray Telescope consists of three autonomous stations installed at the University Campus in the city of Patras. Each station comprises three large (≈ 1 m
2
) plastic ...scintillators and one or more Codalema type RF antennas detecting Extensive Air Showers (EAS), originating from primary particles with energy greater than 10 TeV. The operation and the performance of the Telescope is presented briefly, emphasising the educational activities foreseen in the framework of the HEllenic LYceum Cosmic Observatories Network (HELYCON).
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