44 research outputs found
Objective Synoptic Classificacion combined with High Resolution Meteorological Models for Wind Mesoscale Studies
Prediction of fog episodes at the airport of Madrid-Barajas using different modeling approaches
Sobre el uso de los procesos sinópticos objetivos y los modelos meteorológicos a alta resolución para el estudio de los patrones circulatorios a escala regional
This contribution describes the methodology developed for the automatic classification of what are called the Objective Synoptic Processes (OSP), which is based in the analysis of the
evolution, during three days, of surface pressure and geopotencial height at 500 hPa. The procedure has been applied over an appropriate domain covering the Iberian Peninsula to obtain OSP for the period July-August. Next, for a characteristic day for some of the OSP, a mesoscale meteorological model has been run at high resolution for the region of Catalonia in order to describe the circulatory patterns associated to a given synoptic situation
Evaluacion de algoritmos de inversion lidar sin memoria
Up to now, the extraction of extinction and backscatter coefficients from a lidar signa] or lidar inversion has been done in homogeneous atmospheres by means of the slope method. Yet, it will be shown
that due to its nonlinear behaviour, it can become inaccurate in poor signal-to-noise ratios (SNR). To counteract these problems an altemate method based on least squares minimization is presented. The
inversion error is also assessed as a function of the SNR ratio and the visibility margin.
A further method presented is Klett's analytical solution, which has proved to be the most suitable in inhomogeneous profiles. Again, a parametric study of the inversion error will account for errors in the
estimated boundary value of extinction, missadjustments in the backscatter-extinction relationship and SNR.Peer ReviewedPostprint (published version
Valorization of pellets from municipal WWTP sludge in lightweight clay ceramics
A direct result of the growing number of municipal wastewater-treatment plants (WWTPs) has been an increase in the generation of large amounts of sewage sludge that requires environmentally acceptable final destination. To decrease the volume of sludge, a common technique is drying the sludge at a low temperature in rotary kilns. The result of this process is a granulated material consisting of dehydrated sludge pellets.
After this treatment, this pelletized material becomes easier to manipulate, but it also becomes a more toxic waste, containing dangerous substances, mostly of the lipid type. At its final stage, this material is usually incinerated, used as a comburent material, used as an agricultural fertilizer, or used in the cement industry. Each application has its own problems and requires remediation measures from the safety and environmental viewpoints.
In this study, we looked beyond these possible applications and analyzed the transformation of sewage sludge through a ceramization process into a material similar to expanded clays; we subsequently explored its uses in the building industry or in the agriculture industry, among others. Both the properties of the product material and the production method were characterized, and an environmental analysis was conducted.
The new, lightweight material had a microstructure with open porosity and low thermal conductivity. Environmental characterization such as the leaching test revealed that undetectable amounts of hazardous metals from the sludge were present in the leachate after the sludge went through a thermal treatment, despite their initial presence (with the exception of vanadium, which could pose some restrictions on some of the proposed uses for the final product). Toxicity tests also showed negative results. The study of gaseous emissions during production revealed emissions factors similar to those during the production of conventional clay ceramics, although with higher organic emissions. As for conventional clay ceramics, industrial production would require the implementation of some type of air-depuration system. The results showed that the ceramization of sludge pellets is a promising valorization technique worth considering from both the economic and technological perspectives.Peer ReviewedPostprint (published version
Valorization of pellets from municipal WWTP sludge in lightweight clay ceramics
A direct result of the growing number of municipal wastewater-treatment plants (WWTPs) has been an increase in the generation of large amounts of sewage sludge that requires environmentally acceptable final destination. To decrease the volume of sludge, a common technique is drying the sludge at a low temperature in rotary kilns. The result of this process is a granulated material consisting of dehydrated sludge pellets.
After this treatment, this pelletized material becomes easier to manipulate, but it also becomes a more toxic waste, containing dangerous substances, mostly of the lipid type. At its final stage, this material is usually incinerated, used as a comburent material, used as an agricultural fertilizer, or used in the cement industry. Each application has its own problems and requires remediation measures from the safety and environmental viewpoints.
In this study, we looked beyond these possible applications and analyzed the transformation of sewage sludge through a ceramization process into a material similar to expanded clays; we subsequently explored its uses in the building industry or in the agriculture industry, among others. Both the properties of the product material and the production method were characterized, and an environmental analysis was conducted.
The new, lightweight material had a microstructure with open porosity and low thermal conductivity. Environmental characterization such as the leaching test revealed that undetectable amounts of hazardous metals from the sludge were present in the leachate after the sludge went through a thermal treatment, despite their initial presence (with the exception of vanadium, which could pose some restrictions on some of the proposed uses for the final product). Toxicity tests also showed negative results. The study of gaseous emissions during production revealed emissions factors similar to those during the production of conventional clay ceramics, although with higher organic emissions. As for conventional clay ceramics, industrial production would require the implementation of some type of air-depuration system. The results showed that the ceramization of sludge pellets is a promising valorization technique worth considering from both the economic and technological perspectives.Peer Reviewe
Prediction of fog episodes at the airport of Madrid-Barajas using different modeling approaches
Sobre el uso de los procesos sinópticos objetivos y los modelos meteorológicos a alta resolución para el estudio de los patrones circulatorios a escala regional
This contribution describes the methodology developed for the automatic classification of what are called the Objective Synoptic Processes (OSP), which is based in the analysis of the
evolution, during three days, of surface pressure and geopotencial height at 500 hPa. The procedure has been applied over an appropriate domain covering the Iberian Peninsula to obtain OSP for the period July-August. Next, for a characteristic day for some of the OSP, a mesoscale meteorological model has been run at high resolution for the region of Catalonia in order to describe the circulatory patterns associated to a given synoptic situation