STUDY OF THE INFLUENCES OF GEOGRAPHICAL FACTORS ON THE WIND SPEED AND FREQUENCY. STUDY CASE IN SW OF ROMANIA.

Abstract; The surveillance and the management of the wind resources in Romania represent an issue of national importance considering the fact that the natural potential of the wind is non-polluted resource. This activity requires a great number of observations points and stations of measurement and processing. The paper presents the study carried out in the National Meteorological Administration regarding the influences of geographical factors {location, relief, land cover/land use) on the wind speed and direction in the SW part of Romania. The working methods consisted in statistical analysis of the database climatic parameters (wind speed and direction) for the 1961 - 2000 period of 13 meteorological stations (situated in the SW mountainous region of Romania). The obtained results emphasized the important differences in the wind speed and frequency due to different local geographical conditions and variety of mountainous microclimate. The high baric gradients generate strong winds (with regional character) and the low baric gradients determine weak winds (with local character)

STUDY OF THE INFLUENCES OF GEOGRAPHICAL FACTORS ON THE WIND SPEED AND FREQUENCY. STUDY CASE IN SW OF ROMANIA.

Abstract; The surveillance and the management of the wind resources in Romania represent an issue of national importance considering the fact that the natural potential of the wind is non-polluted resource. This activity requires a great number of observations points and stations of measurement and processing. The paper presents the study carried out in the National Meteorological Administration regarding the influences of geographical factors {location, relief, land cover/land use) on the wind speed and direction in the SW part of Romania. The working methods consisted in statistical analysis of the database climatic parameters (wind speed and direction) for the 1961 - 2000 period of 13 meteorological stations (situated in the SW mountainous region of Romania). The obtained results emphasized the important differences in the wind speed and frequency due to different local geographical conditions and variety of mountainous microclimate. The high baric gradients generate strong winds (with regional character) and the low baric gradients determine weak winds (with local character)

Rumble: Data Independence for Large Messy Data Sets

This paper introduces Rumble, an engine that executes JSONiq queries on large, heterogeneous and nested collections of JSON objects, leveraging the parallel capabilities of Spark so as to provide a high degree of data independence. The design is based on two key insights: (i) how to map JSONiq expressions to Spark transformations on RDDs and (ii) how to map JSONiq FLWOR clauses to Spark SQL on DataFrames. We have developed a working implementation of these mappings showing that JSONiq can efficiently run on Spark to query billions of objects into, at least, the TB range. The JSONiq code is concise in comparison to Spark's host languages while seamlessly supporting the nested, heterogeneous data sets that Spark SQL does not. The ability to process this kind of input, commonly found, is paramount for data cleaning and curation. The experimental analysis indicates that there is no excessive performance loss, occasionally even a gain, over Spark SQL for structured data, and a performance gain over PySpark. This demonstrates that a language such as JSONiq is a simple and viable approach to large-scale querying of denormalized, heterogeneous, arborescent data sets, in the same way as SQL can be leveraged for structured data sets. The results also illustrate that Codd's concept of data independence makes as much sense for heterogeneous, nested data sets as it does on highly structured tables.Comment: Preprint, 9 page

Design of an Optically Accessible Intake Manifold for Characterization of Liquid and Gaseous Jets in PFI Operating Conditions

The intake manifold and its components play a key role in the proper formation of air–fuel mixtures suitable for correct engine operation. In this article, starting from the original intake manifold design fitted to an optically accessible spark-ignited engine, a new solution was developed so as to allow the application of high-speed imaging of the fuel jet located between the runner and intake valves (Port Fuel Injection). To compare the two designs in terms of overall engine performance parameters such as volumetric efficiency, 0D/1D simulations were performed in motored conditions. Measurements at different crankshaft speed values were used for calibrating the intake line parameters and providing boundary conditions. Finite Element Analysis (FEM) was performed in SolidWorks to verify the structural strength of the new design when operating in the most critical conditions, i.e., boosted operation. As an overall conclusion, the results show that the new design guarantees a wider range of intake pressure values during the intake stroke, thus expanding the possible operative points. This can be obtained without compromising structural integrity, given that predicted safety factors were well above acceptable limits even for relatively high boost levels