614 research outputs found
Snow water equivalent modeling components in NewAge-JGrass
This paper presents a package of modified temperature-index-based snow
water equivalent models as part of the hydrological modeling system
NewAge-JGrass. Three temperature-based snow models are integrated into the
NewAge-JGrass modeling system and use many of its components such as those
for radiation balance (short wave radiation balance, SWRB), kriging (KRIGING), automatic calibration
algorithms (particle swarm optimization) and tests of goodness of fit
(NewAge-V), to build suitable modeling solutions (MS). Similarly to all the
NewAge-JGrass components, the models can be executed both in raster and in
vector mode. The simulation time step can be daily, hourly or sub-hourly,
depending on user needs and availability of input data. The MS are applied on
the Cache la Poudre River basin (CO, USA) using three test applications.
First, daily snow water equivalent is simulated for three different
measurement stations for two snow model formulations. Second, hourly snow
water equivalent is simulated using all the three different snow model
formulae. Finally, a raster mode application is performed to compute snow
water equivalent maps for the whole Cache la Poudre Basin
The JGrass-NewAge system for forecasting and managing the hydrological budgets at the basin scale: models of flow generation and propagation/routing
Abstract. This paper presents a discussion of the predictive capacity of the implementation of the semi-distributed hydrological modeling system JGrass-NewAge. This model focuses on the hydrological budgets of medium scale to large scale basins as the product of the processes at the hillslope scale with the interplay of the river network. The part of the modeling system presented here deals with the: (i) estimation of the space-time structure of precipitation, (ii) estimation of runoff production; (iii) aggregation and propagation of flows in channel; (v) estimation of evapotranspiration; (vi) automatic calibration of the discharge with the method of particle swarming. The system is based on a hillslope-link geometrical partition of the landscape, combining raster and vectorial treatment of hillslope data with vector based tracking of flow in channels. Measured precipitation are spatially interpolated with the use of kriging. Runoff production at each channel link is estimated through a peculiar application of the Hymod model. Routing in channels uses an integrated flow equation and produces discharges at any link end, for any link in the river network. Evapotranspiration is estimated with an implementation of the Priestley-Taylor equation. The model system assembly is calibrated using the particle swarming algorithm. A two year simulation of hourly discharge of the Little Washita (OK, USA) basin is presented and discussed with the support of some classical indices of goodness of fit, and analysis of the residuals. A novelty with respect to traditional hydrological modeling is that each of the elements above, including the preprocessing and the analysis tools, is implemented as a software component, built upon Object Modelling System v3 and jgrasstools prescriptions, that can be cleanly switched in and out at run-time, rather than at compiling time. The possibility of creating different modeling products by the connection of modules with or without the calibration tool, as for instance the case of the present modeling chain, reduces redundancy in programming, promotes collaborative work, enhances the productivity of researchers, and facilitates the search for the optimal modeling solution
Influence of build orientation on static and axial fatigue properties of maraging steel specimens produced by additive manufacturing
Abstract Additive manufacturing involves a layer-by-layer build-up of mechanical parts and it is a manufacturing technology that can be adopted with different engineering metal materials like steels, aluminium and titanium alloys. Aim of the present investigation is to analyse the influence of the build orientation on static and axial fatigue properties of maraging steel specimens manufactured by Direct Metal Laser Sintering (DMLS) of EOS metal powders. After manufacturing, some of the specimens were subjected to age hardening heat treatment (490 °C for 6 hours, followed by air cooling). Both heat treated and as-manufactured specimens have been built at 0° as well as at 90° orientation with respect to the specimen's axis. Analyses of the crack initiation point are performed in order to investigate the fatigue failure mechanisms. Finally, the fatigue strength of the additively manufactured specimens was compared with that exhibited by vacuum melted specimens of the same steel reported in literature
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