Search results for "HV"
showing 10 items of 353 documents
Numerical study of shock formation in the dispersionless Kadomtsev-Petviashvili equation and dispersive regularizations
2013
The formation of singularities in solutions to the dispersionless Kadomtsev-Petviashvili (dKP) equation is studied numerically for different classes of initial data. The asymptotic behavior of the Fourier coefficients is used to quantitatively identify the critical time and location and the type of the singularity. The approach is first tested in detail in 1+1 dimensions for the known case of the Hopf equation, where it is shown that the break-up of the solution can be identified with prescribed accuracy. For dissipative regularizations of this shock formation as the Burgers' equation and for dispersive regularizations as the Korteweg-de Vries equation, the Fourier coefficients indicate as …
Relationships between climate and soil hydrological and erosional characteristics along climatic gradients in Mediterranean limestone areas
1998
An investigation was undertaken to determine the relationships between climate and soil hydrological and erosional characteristics. Rainfall simulation experiments were carried out along three climatological gradients on similar limestone lithologies in the Mediterranean region. Standard experiments were used to characterize each site so that an objective comparison could be made. At each of the eleven south-facing slopes three experiments were carried out. A total of 33 plots were selected for the experiments; located in the Galilee and Carmel Mountains (Israel), Crete (Greece) and Alicante (Spain). Simulated rainfall was used in order to measure time to ponding and runoff, steady-state in…
The impact of cotton geotextiles on soil and water losses from Mediterranean rainfed agricultural land
2010
High soil erosion risk of Mediterranean cultivated soils is due to steep slopes, high rainfall intensities and low vegetation cover. Traditional land management as ploughing and herbicides give rise to high soil erosion rates. This paper reports on the use of a cotton geotextiles to control soil and water losses on agricultural land under Mediterranean climatic conditions. Eight paired plots (1, 2, 4 and 16 m2) were studied during 1-year period under natural rainfall. Forty rainfall simulations under wet and dry climatic conditions, and water drop penetration time (WDPT) tests, were carried out in order to analyze the effect of a geotextile on soil and water losses on a typical rainfed orch…
Shining castles and humans of metal/floral appearance ? metaphorical language in the Palaiologan romances Kallimachos and Velthandros
2019
About eight centuries after Heliodorus, the Greek novel resurfaced in the twelfth century, in Komnenian Byzantium, and again two centuries later under the Palaiologan dynasty. This latter literary revival was due to the political stability of the imperial Byzantine government, which promoted cultural production, rhetorical education, and patronage networks. Kallimachos and Velthandros, two Palaiologan romances presented as court literature, combine ancient and medieval tropes with rhetorical artistry to blur the boundaries between the artificial and the natural. Castles and objects made of precious metals thus resemble living, natural spaces, and human characters are portrayed in metallurgi…
Ground Coupled Heat Pumps in Mixed Climate Areas: Design, Characterization and Optimization
2010
This contribution reviews the research work developed by the authors on the design, characterization and optimization of ground coupled heat pumps in mixed climates areas. The design of a ground coupled heat pump HVAC system starts with the estimation of the thermal loads that the air-conditioned area demands. The capacity of the ground source airconditioning system is determined from this thermal load estimation. With this value and a proper estimation of the ground thermal properties, the characteristics of the water to water heat pump and the required length and layout of the borehole heat exchangers are estimated. Determining ground thermal properties is crucial for an accurate design o…
1919. gada Mečislava Centneršvēra veidotais ķīmijas praktikums
2019
Raksts par Latvijas Universitātes Muzeja krājumā esošo poļu fizikālķīmiķa Mečislava Centneršvēra (1874-1944) 1919. gadā veidoto ķīmijas praktikumu inženieriem, mehāniķiem un arhitektiem.
Das Blutbild und die Atmungsintensität des Misgurnus fossilis bei verschiedenen Atmungsbedingungen [Misgurnus fossilis elpošanas intensitāte un asiņu…
1935
Teksts vācu valodā, kopsavilkums latviešu valodā.
Dealing with rural-urban economic welfare challenges in the Nordic countries – a theory-based overview
2020
Abstract Geography has played an important part in creating the Nordic welfare states. This article discusses how the urban-rural dimension has been dealt with in the context of developing economic welfare. Four different policy interventions are presented: exogeneous shocks, buy out, palliative treatment and endogenous growth through innovation. Of these, the latter prevails in contemporary policy discussions. The application of policy measures varies substantially between the Nordic countries. We have different Nordic models rather than a single model. While in the aftermath of World War II economic development and welfare arguments combined to justify geographical centralisation, the pre…
Multicomponent relativistic dissipative fluid dynamics from the Boltzmann equation
2022
We derive multicomponent relativistic second-order dissipative fluid dynamics from the Boltzmann equations for a reactive mixture of $N_{\text{spec}}$ particle species with $N_q$ intrinsic quantum numbers (e.g. electric charge, baryon number, and strangeness) using the method of moments. We obtain the continuity equations for multiple conserved charges as well as the conservation equations for the total energy and momentum in the single-fluid approximation. These $4+N_q$ conservation laws are closed by deriving the second-order equations of motion for the dissipative quantities in the $(10+4N_q)$-moment approximation. The resulting fluid-dynamical equations are formally similar to those of …