Using remote sensing multispectral data and GIS techniques for the geological mapping of Halki Island

Στην εργασία αυτή παρουσιάζεται ο Γεωλογικός Χάρτης κλίμακας 1/50.000 Φύλλο "Νήσος  Χάλκη"  πουεκδόθηκε  από  το  ΙΓΜΕ.  Για  τη  δημιουργία  του  χάρτη  έγινε συνδυαστική χρήση δορυφορικών πολυφασματικών δεδομένων (Landsat TM   & ETM  and Terra    ASTER), και χαρτογράφησης στο πεδίο με χρήση DGPS   . Όλα τα δεδομένα εισήχθησαν στην ειδικά σχεδιασμένη γεωβάση του ΙΓΜΕ. Μετά τους απαραίτητους τοπολογικούς ελέγχους και τις αναγκαίες διορθώσεις τα δεδομένα ενοποιήθηκαν και έγινε η επεξεργασία τους με σκοπό τη δημιουργία του  τελικού χάρτη.In this paper we present the combined use of remote sensing and GIS techniques for the geological mapping of Halki Island at 1/50.000 scale. The geological formations, geotectonic units and tectonic structures were recognized in situ and mapped. Interpretation  of  multispectral  satellite  images  (Landsat  TM  &  ETM  and  Terra ASTER) has been carried out in order to detect the linear or not structures of the study area. Different band ratio was also used in order to distinguish and map the limits of the different geotectonic units. The in situ mapping was enhanced with data derived from the digital processing of the satellite data. All the analogical and digital data were imported in a geodatabase specially designed for geological data. After the necessary topological control and corrections, the data were unified and processed in order to create the final map layout at 1/50.000 scale.

Implementation of the CRPA model in the GENIE event generator and analysis of nuclear effects in low-energy transfer neutrino-nucleus interactions

We present the implementation and validation of the Hartree-Fock continuum random phase approximation (HF-CRPA) model in the GENIE neutrino-nucleus interaction event generator and a comparison of the subsequent predictions to experimental measurements of lepton kinematics from interactions with no mesons in the final state. These predictions are also compared to those of other models available in GENIE. It is shown that, with respect to these models, HF-CRPA predicts a significantly different evolution of the cross section when moving between different interaction targets, when considering incoming anti-neutrinos compared to neutrinos and when changing neutrino energies. These differences are most apparent for interactions with low energy and momentum transfer. It is also clear that the impact of nucleon correlations within the HF-CRPA framework is very different than in GENIE's standard implementation of RPA corrections. Since many neutrino oscillation experiments rely on their input model to extrapolate between targets, flavours, and neutrino energies, the newly implemented HF-CRPA model provides a useful means to verify that such differences between models are appropriately covered in oscillation analysis systematic error budgets.Comment: 13 pages, 12 figures. Significant update from previous versio

Axial turbo-expander design for organic Rankine cycle waste-heat recovery with comparative heavy-duty diesel engine drive-cycle performance assessment

Despite the high thermal efficiency achieved by modern heavy-duty diesel engines, over 40% of the energy contained in the fuel is wasted as heat either in the cooling or the exhaust gases. By recovering part of the wasted energy, the overall thermal efficiency of the engine increases and the pollutant emissions are reduced. Organic Rankine cycle (ORC) systems are considered a favourable candidate technology to recover exhaust gas waste heat, because of their simplicity and small backpressure impact on the engine performance and fuel consumption. The recovered energy can be transformed into electricity or directly into mechanical power. In this study, an axial turbine expander for an ORC system was designed and optimized for a heavy-duty diesel engine for which real-world data were available. The impact of the ORC system on the fuel consumption under various operating points was investigated. Compared to an ORC system equipped with a radial turbine expander, the axial design improved fuel consumption by between 2 and 10% at low and high engine speeds. Finally, the benefits of utilising ORC systems for waste heat recovery in heavy-duty trucks is evaluated by performing various drive cycle tests, and it is found that the highest values of fuel consumption were found in the NEDC and the HDUDDS as these cycles generally involve more dynamic driving profiles. However, it was in these cycles that the ORC could recover more energy with an overall fuel consumption reduction of 5 and 4.8%, respectively

Angular distributions in Monte Carlo event generation of weak single-pion production

One of the substantial sources of systematic errors in neutrino oscillation experiments that utilize neutrinos from accelerator sources stems from a lack of precision in modeling single-pion production (SPP). Oscillation analyses rely on Monte Carlo event generators (MC), providing theoretical predictions of neutrino interactions on nuclear targets. Pions produced in these processes provide a significant fraction of oscillation signal and background on both elementary scattering and detector simulation levels. Thus, it is of critical importance to develop techniques that will allow us to accommodate state-of-the-art theoretical models describing SPP into MCs. In this work, we investigate various algorithms to implement single-pion production models in Monte Carlo event generators. Based on comparison studies, we propose a novel implementation strategy that combines satisfactory efficiency with high precision in reproducing details of theoretical models predictions, including pion angular distributions. The proposed implementation is model-independent, thereby providing a framework that can include any model for SPP. We have tested the new algorithm with the Ghent Low Energy Model for single-pion production implemented in the NuWro Monte Carlo event generator.Comment: 13 pages, 8 figure

Thermal-hydrodynamic behaviour of coated pivoted pad thrust bearings: Comparison between Babbitt, PTFE and DLC

The hydrodynamic lubrication and thermal analysis of tilting pad thrust bearings has been a major subject for many studies in the field of tribology. There is only a limited number of studies regarding thrust bearings with coated surfaces. The purpose of this study is to build a parametric, iterative algorithm in order to perform a complete thermal and hydrodynamic lubrication analysis for pivoted pad thrust bearings with coatings. The analytical model is mainly based on the energy, continuity and Navier-Stokes equations, which are solved numerically with the Semi-Implicit Method for Pressure Linked Equations Consistent (SIMPLEC) method. The analysis focuses on a single pivoted pad of the thrust bearing. The thermal properties of the coating material are taken into account and the resulting thermal and flow fields are solved. The basic hydrodynamic and tribological characteristics are calculated for an uncoated, a Babbitt coated, a PTFE coated and a diamond like carbon (DLC) coated pivoted pad thrust bearing. The pressure and the film thickness distribution, as well as the load capacity and the frictional forces, are determined for several pad positions and velocities of the rotor. A mineral oil lubricant is used to estimate the shear thinning or thickening effects on the pad tribological performance. The results indicate that pads coated with PTFE and DLC show lower friction forces compared to the common steel and Babbitt applications. At the same time, the DLC coating seems to affect the bearing's flow and thermal fields less than the PTFE, making it more suitable for thrust bearings applications

Uncertainties on the νμ\nu_{\mu}/νe\nu_{e}, νˉμ\bar{\nu}_{\mu}/νˉe\bar{\nu}_{e} and νe\nu_{e}/νˉe\bar{\nu}_{e} cross-section ratio from the modelling of nuclear effects and their impact on neutrino oscillation experiments

Recent studies have demonstrated non-trivial behaviours in the cross-section extrapolation from $\nu_{\mu}$ ($\bar{\nu}_{\mu}$) to $\nu_{e}$ ($\bar{\nu}_{e}$) interactions on nuclear targets in the charged-current quasi-elastic (CCQE) regime. In this article, the potential for mis-modeling of $\nu_{\mu}$/$\nu_{e}$, $\bar{\nu}_{\mu}$/$\bar{\nu}_{e}$ and $\nu_{e}$/$\bar{\nu}_{e}$ cross-section ratios due to nuclear effects is quantified by considering the model spread within the full kinematic phase space for CCQE interactions. Its impact is then propagated to a simulated experimental configuration based on the Hyper-K experiment, which is dominated by CCQE interactions. Although a relatively large discrepancy between theoretical models is confirmed for forward lepton angles at neutrino energies below 300 MeV and for a new region of phase space at lepton angles above $100^{\circ}$, both regions are demonstrated to contribute a very small portion of the Hyper-K (or T2K) flux integrated cross section. Overall, a systematic uncertainty on the oscillated flux-averaged $\nu_{e}$/$\bar{\nu}_{e}$ cross-section ratio is estimated to be $\sim$2%. A similar study was also conducted for the proposed lower-energy ESS$\nu$SB experiment configuration, where the resulting uncertainty was found to be larger.Comment: 14 pages, 10 figures. Fixed abstract misformating on arxiv pag