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The thermodynamic and physical properties of Helium (He) and Hydrogen (H) mixtures are crucial form an astrophysical perspective. Nowadays, it is well known that these two elements constitute roughly 95% of the matter in the solar system. The high-pressure equation of He state doped with H is calculated in the framework of density functional theory (DFT) for three crystallographic structures. Namely, the Body Centered Cubic (BCC), Face Centered Cubic (FCC), and hexagonal close packed (HCP) structures have been studied. The equations of state (EOS) are provided for the He0.90H0.10 and He0.70H0.30 mixtures and the energy of the same mixtures are calculated with the earlier structures. The band structure for pressures of 0, 75 and 150 GPa were estimated by our calculations for the presumed crystal structures in the case of pure He and He0.70H0.30 mixture for comparison. The k(x) - k(y) cuts of the Bloch Spectral Functions (BSF) are presented for the pure He and He0.70H0.30 mixture for the three structures to explore the impact of doping on electronic properties. In addition, electrical resistivity calculations of the mentioned structures were carried out for mixtures with 10, 15, 20 and 30% of H. At final stage, the enthalpy (Delta H) of these latest mixtures have been deduced for the three crystal structures.

The thermodynamic and physical properties of Helium (He) and Hydrogen (H) mixtures are crucial form an astrophysical perspective. Nowadays, it is well known that these two elements constitute roughly 95% of the matter in the solar system. The high-pressure equation of He state doped with H is calculated in the framework of density functional theory (DFT) for three crystallographic structures. Namely, the Body Centered Cubic (BCC), Face Centered Cubic (FCC), and hexagonal close packed (HCP) structures have been studied. The equations of state (EOS) are provided for the He0.90H0.10 and He0.70H0.30 mixtures and the energy of the same mixtures are calculated with the earlier structures. The band structure for pressures of 0, 75 and 150 GPa were estimated by our calculations for the presumed crystal structures in the case of pure He and He0.70H0.30 mixture for comparison. The k(x) - k(y) cuts of the Bloch Spectral Functions (BSF) are presented for the pure He and He0.70H0.30 mixture for the three structures to explore the impact of doping on electronic properties. In addition, electrical resistivity calculations of the mentioned structures were carried out for mixtures with 10, 15, 20 and 30% of H. At final stage, the enthalpy (Delta H) of these latest mixtures have been deduced for the three crystal structures., QC 20220304

The final publication is available at Springer via http://dx.doi.org/10.1007/s11227-015-1607-5, Hydraulic solvers for the simulation of flows and pressures in water distribution systems (WDS) are used extensively, and their computational performance is key when considering optimization problems. This paper presents an approach to speedup the hydraulic solver using OpenMP with two efficient methods for WDS simulation. The paper identifies the different tasks carried out in the simulation, showing their contribution to the execution time, and selecting the target tasks for parallelization. After describing the algorithms for the selected tasks, parallel OpenMP versions are derived, with emphasis on the task of linear system update. Results are presented for four different large WDS models, showing considerable reduction in computing time

The final publication is available at Springer via http://dx.doi.org/10.1007/s11227-015-1607-5, Hydraulic solvers for the simulation of flows and pressures in water distribution systems (WDS) are used extensively, and their computational performance is key when considering optimization problems. This paper presents an approach to speedup the hydraulic solver using OpenMP with two efficient methods for WDS simulation. The paper identifies the different tasks carried out in the simulation, showing their contribution to the execution time, and selecting the target tasks for parallelization. After describing the algorithms for the selected tasks, parallel OpenMP versions are derived, with emphasis on the task of linear system update. Results are presented for four different large WDS models, showing considerable reduction in computing time

In this paper, the electronic and the structural (Lattice constant) properties of ?-BeH2, which is the ground state of BeH2, in orthorhombic crystal system, with space group (Ibam) are calculated using density functional theory. The Kohn-Sham equations were solved; using the Full-potential linearized augmented Plane-wave (FP-LAPW) method. With the apt choice of Ueff = U

In this paper, the electronic and the structural (Lattice constant) properties of ?-BeH2, which is the ground state of BeH2, in orthorhombic crystal system, with space group (Ibam) are calculated using density functional theory. The Kohn-Sham equations were solved; using the Full-potential linearized augmented Plane-wave (FP-LAPW) method. With the apt choice of Ueff = U

In this paper, the electronic and the structural (Lattice constant) properties of ?-BeH2, which is the ground state of BeH2, in orthorhombic crystal system, with space group (Ibam) are calculated using density functional theory. The Kohn-Sham equations were solved; using the Full-potential linearized augmented Plane-wave (FP-LAPW) method. With the apt choice of Ueff = U

Positron lifetimes have been calculated in bulk and monovacancies for most of the elements of the periodic table. Self-consistent and non-self-consistent schemes have been used for the calculation of the electronic structure in the solid, as well as different parameterizations for the positron enhancement factor and correlation energy. The ratio between the monovacancy and bulk lifetimes has been analyzed. This ratio shows a periodic behaviour with atomic number in all the calculation methods and it is in agreement with selected experimental data. The ratio shows, in contradiction to previous assumptions, sensitiveness to the approximations used in the calculations. This extensive work has allowed us to study and enlighten features of the theory and computing methods broadly used nowadays in simulating, studying and understanding positronic parameters.

The use of high-throughput density functional theory (DFT) calculations to screen for new materials and conduct fundamental research presents an exciting opportunity for materials science and materials innovation. High-throughput DFT typically involves computations on hundreds, thousands, or tens of thousands of compounds, and such a change of scale requires new calculation and data management methodologies. In this article, we describe aspects of the necessary data infrastructure for such projects to handle data generation and data analysis in a scalable way. We discuss the problem of accurately computing properties of compounds across diverse chemical spaces with a single exchange correlation functional, and demonstrate that errors in the generalized gradient approximation are highly dependent on chemical environment.

We have performed first principles calculations to determine the structural properties of InP compound, in zinc blende, NaCl, wurtzite, NiAs and CsCl structures, using density functional theory (DFT) and the full potential linearized augmented plane waves method (FP-LAPW). To represent the exchange and correlation effects we used the generalized gradient approximation (GGA), with the Wu-Cohen, as implemented in the Wien2k package. We find that the most stable structure is the zincblende type and under pressure is observed. We analyze in detail the band structure and density of states in the more stable phase, being shown a semiconductor behavior with direct energy band gap., Se ha realizado cálculos de primeros principios para determinar las propiedades estructurales del compuesto InP, en las estructuras zinc blenda, NaCl, wurzita, NiAs y CsCl, utilizando la teoría del funcional densidad (DFT) y el método de ondas planas aumentadas y linealizadas con potencial completo (FP-LAPW). Para representar los efectos de intercambio y correlación, empleamos la aproximación de gradiente generalizado (GGA); con el novedoso potencial de Wu-Cohen, como está implementado en el paquete Wien2k. Se encontró que la estructura más estable es la tipo zinc blenda y se observó la transición de fase estructural de ZB a NaCl bajo presión. Analizando en detalle la estructura de bandas y la densidad de estados en la fase más estable, evidenciándose un comportamiento semiconductor con brecha de energía prohibida directa.

Positron lifetimes have been calculated in bulk and monovacancies for most of the elements of the periodic table. Self-consistent and non-self-consistent schemes have been used for the calculation of the electronic structure in the solid, as well as different parameterizations for the positron enhancement factor and correlation energy. The ratio between the monovacancy and bulk lifetimes has been analyzed. This ratio shows a periodic behaviour with atomic number in all the calculation methods and it is in agreement with selected experimental data. The ratio shows, in contradiction to previous assumptions, sensitiveness to the approximations used in the calculations. This extensive work has allowed us to study and enlighten features of the theory and computing methods broadly used nowadays in simulating, studying and understanding positronic parameters.

Se describe los diferentes estandares NMEA y se explican los distintos emisores posibles. Se personaliza para el emisor GPS y para las sentencias propietario. Se analiza en detalle las sentencias GGA, GSA y GSV, así como las sentencias propietario de la casa Garmin. Por ultimo se pone un ejemplo de un bloque de sentencias.

Se describe los diferentes estandares NMEA y se explican los distintos emisores posibles. Se personaliza para el emisor GPS y para las sentencias propietario. Se analiza en detalle las sentencias GGA, GSA y GSV, así como las sentencias propietario de la casa Garmin. Por ultimo se pone un ejemplo de un bloque de sentencias.

Se describe los diferentes estandares NMEA y se explican los distintos emisores posibles. Se personaliza para el emisor GPS y para las sentencias propietario. Se analiza en detalle las sentencias GGA, GSA y GSV, así como las sentencias propietario de la casa Garmin. Por ultimo se pone un ejemplo de un bloque de sentencias.

Se describe los diferentes estandares NMEA y se explican los distintos emisores posibles. Se personaliza para el emisor GPS y para las sentencias propietario. Se analiza en detalle las sentencias GGA, GSA y GSV, así como las sentencias propietario de la casa Garmin. Por ultimo se pone un ejemplo de un bloque de sentencias.

The adsorption of NO on the (1 1 1) and (1 1 0) surfaces of ceria (CeO2) was studied using projector-augmented wave (PAW) method based density-functional theory within the generalized gradient approximation (GGA). Several adsorption sites for NO on the stoichiometric surfaces are found, all with weak molecule-surface interaction. The adsorption on the reduced surfaces is much stronger. The O-ends of the adsorbed NO molecules fill the oxygen vacancies and the N–O bonds are elongated. If two such adsorbed NO molecules, residing at neighbouring sites, meet, their N-ends will form a strong N–N bond with little or no barrier. This is an intermediate step towards dissociation of free N2 which is calculated to be strongly thermodynamically driven.

The adsorption of NO on the (111) and (110) surfaces of ceria (CeC2) was studied using projector-augmented wave (PAW) method based density-functional theory within the generalized gradient approximation (GGA). Several adsorption sites for NO on the stoichiometric surfaces are found, all with weak molecule-surface interaction. The adsorption on the reduced surfaces is much stronger. The O-ends of the adsorbed NO molecules fill the oxygen vacancies and the N-O bonds are elongated. If two such adsorbed NO molecules, residing at neighbouring sites, meet, their N-ends will form a strong N-N bond with little or no barrier. This is an intermediate step towards dissociation of free N-2 which is calculated to be strongly thermodynamically driven., QC 20100525

The first half of the Masters thesis is the result of a survey made on the behalf of the Swedish company KORDAB International AB. The survey includes an overview of different positioning systems and some wireless communication techniques available on the market today. Positioning systems discussed are GPS, DGPS, AGPS and GSM positioning. Mobile Internet connections through mobile phones and communication through radio modems are mentioned and described as examples of wireless communication techniques. Examples of techniques described are HSCSD, GPRS, UMTS and MOBITEX. KORDAB is in the starting blocks to implement a real time positioning feature into their own technical information system GEOSECMA. This survey will give them a base which will help them to decide on which system to use for this feature. The second half of the thesis includes parts concerning a prototype made to exemplify how KORDAB could implement the real time positioning feature into GEOSECMA. The NMEA 0183 protocol, reference systems and transformation are described to give the necessary background knowledge for the construction and functionality of the prototype. The prototype is a GPS-communicator made as an interface between a GPS-receiver and GEOSECMA and its functionality is also described in this second half of the thesis. Feasible applications are also discussed to show the possibilities real time positioning gives. One application discussed is “Zoom and Auto highlighting”. This application is designed to help user of GEOSECMA to zoom in the map and highlighting the nearest object at current location.

The first half of the Masters thesis is the result of a survey made on the behalf of the Swedish company KORDAB International AB. The survey includes an overview of different positioning systems and some wireless communication techniques available on the market today. Positioning systems discussed are GPS, DGPS, AGPS and GSM positioning. Mobile Internet connections through mobile phones and communication through radio modems are mentioned and described as examples of wireless communication techniques. Examples of techniques described are HSCSD, GPRS, UMTS and MOBITEX. KORDAB is in the starting blocks to implement a real time positioning feature into their own technical information system GEOSECMA. This survey will give them a base which will help them to decide on which system to use for this feature. The second half of the thesis includes parts concerning a prototype made to exemplify how KORDAB could implement the real time positioning feature into GEOSECMA. The NMEA 0183 protocol, reference systems and transformation are described to give the necessary background knowledge for the construction and functionality of the prototype. The prototype is a GPS-communicator made as an interface between a GPS-receiver and GEOSECMA and its functionality is also described in this second half of the thesis. Feasible applications are also discussed to show the possibilities real time positioning gives. One application discussed is “Zoom and Auto highlighting”. This application is designed to help user of GEOSECMA to zoom in the map and highlighting the nearest object at current location.