MS Atmospheric Science Thesis Defense

MS AS Thesis Defenses
Wednesday, 27 February 2013, 1:00 – 5:00 PM, F-318
(including abstracts)

1:00 PM Lucille Joanna S. Borlaza

Evaluation of the Efficiency of an Ultrafine Titanium Dioxide-Based Paint for Removing Nitrogen Oxides in an Indoor and Outdoor Environment

Adviser: Dr. James Simpas

Panelists: Dr. Mariano Estoque, Dr. Gemma Narisma, Mr. Anthony Zosa

Abstract

Evaluation of the Efficiency of an Ultrafine Titanium Dioxide-Based Paint for Removing Nitrogen Oxides in an Indoor and Outdoor Environment Air pollution occurs both indoors and outdoors, air pollutant levels sometimes exceed World Health Organization air quality guideline values by a factor of three or more in urban areas. The development of innovative materials that can be easily applied on facades with de-polluting properties could be a significant step towards the improvement of air quality. The Fujishima and Honda discovery of photo-catalysis in the early 1970’s has attracted extensive attention due to its number of potential applications, one of which is degradation of pollutants. It is the purpose of this study to evaluate the NOx reduction efficiency of a styrene acrylic water-based paint with 7.5% ultrafine titanium dioxide (UF TiO2) photo-catalytic ingredient by comparing its effectiveness in an indoor and outdoor environment. NO2 mass concentrations as well as meteorological conditions were measured before, during and after the application of UF TiO2 paint in an indoor and outdoor environment. Melinex film strips coated with UF TiO2 paint were also exposed for 10 months and subjected to ion chromatography analysis. Results indicate an average of 10% reduction of NO2 mass concentration in the outdoor environment, while 51% increase in the indoor environment. A step-wise linear regression model showed significant dependence of NO2 mass concentration with wind speed. Ion chromatography analysis on the paint strips yielded a 0.29-2.24 g/m2 NOx removal in the outdoor environment for 10 months. On the other hand, a 0.04 g/m2 NOx removal is measured in the indoor environment. According to the series of evaluation, a styrene acrylic water-based paint with 7.5% UF TiO2 photo-catalytic ingredient is more effective in an outdoor environment where there is sufficient light, and moisture. Wind dispersion is also a key in keeping the levels of air pollution diluted. It is recommended that the UF TiO2-based paint be used in areas where the presence of the paint’s requirements is abundant and where minimal pollution build-up could occur.

2:00 PM Juanito S. Galang

The Effects of Northern Luzon Topography on Typhoon Chan-hom (2009)

Adviser: Dr. Mariano Estoque

Panelists: Dr. Nofel Lagrosas, Dr. Gemma Narisma, Dr. James Simpas

Abstract

The Effects of Northern Luzon Topography on Typhoon Chan-hom (2009) Topography is known to affect a tropical cyclones (TC) track and intensity by modifying its circulation. One particularly interesting case is Typhoon Chan-hom (2009) as it made landfalls on the mountainous island of Luzon. The typhoon produced copious rain, deadly flash floods, and mud slides over northern Luzon, with an estimated 1.4 billion pesos of damage and over 120 fatalities. In this study, we investigate the physical processes involved in the interaction of a typhoon with the Luzon islands’ topography, by using high-resolution numerical simulations of Typhoon Chan-hom (2009), with an emphasis on the intensity and rainfall distribution over the island. The main objective of the study is to understand the effects of topography on tropical cyclone by using a high-resolution, nonhydrostatic, 5th generation Pennsylvania State University-NCAR Mesoscale Model (MM5). The model is initialized at 0000 UTC 07 May 2009, 12 hours prior to the Luzon landfall, and integrated for 24 hours. To further investigate the model on simulated tracks, intensity and rainfall in Typhoon Chan-hom, we have successfully conducted sensitivity simulation using various physical parameterizations in MM5, and all have high resolution topography included. The results are compared with the observations. All the simulated intensity on sensitivity experiments is underestimated. The simulated 24-hr rainfall concentrations for the sensitivity experiments are along the track of the typhoon. The Kain-Fritch, Goddard Graupel and the Medium Range Forecast scheme obtain the highest coefficient of determination for the 24-hr rainfall of the Cumulus, Microphysics and Planetary Boundary Layer parameterizations respectively. The sensitivity experiments on tracks are accomplished to obtain the best configuration of the model. The model simulated typhoons track from the best configuration simulation, are in good agreement with the observations. The simulated intensity from the best configuration are underestimated compares to the observed. The best configuration simulation also showed that the rainfall structure and storm-topography interactions are realistically captured by MM5 at the resolution used in our work, therefore much can be learned from the two idealized experiments. These idealized sensitivity simulations, one reducing the islands’ topography by 50% and the other removing the islands’ topography. The results are compared with the observations and the best configuration simulation. These experiments were designed to examine and isolate the influences of the islands’ topography and landmasses on Chan-homs’ rainfall. The simulation with the topography removed and half of topography only removed showed that the weakening and structural changes over land are mostly controlled by the islands’ topography.

3:00 PM Julie Mae B. Dado

The Effects of Urban Expansion in Metro Manila on the Southwest Monsoon Rainfall

Adviser: Dr. Gemma Narisma

Panelists: Dr. Mariano Estoque, Dr. Nofel Lagrosas, Dr. James Simpas

Abstract

Climate models often do not take into account land use change effects in modeling climatic changes. However, modifications in land cover such as urbanization, affect the partitioning of the water and energy balance, which in turn influences temperature and rainfall vertical winds, which enhances the uplifting of moist winds brought about by the SWM. This consequently enhances convection and rainfall formation. Observation data analysis shows that JAS SWM rainfall since the 1960s has increased by about 29%. Comparison of model results with observation data from three Metro Manila stations indicate that without urban expansion, rainfall increases only by about 15%. With expanded urban impacts included, the modeled increase in rainfall is about 26%, which is much closer to the observed value. This strongly indicates the importance of the climatic impacts of urban expansion on the SWM rainfall. This study therefore illustrates the significance of incorporating land use changes together with CO2 changes in climatic change modeling especially at the scale of local impacts.

4:00 PM Carlo A. Jamandre

Satellite Rainfall Validation and Assimilation Into a Weather Forecast Model

Adviser: Dr. Gemma Narisma

Panelists: Dr. Mariano Estoque, Dr. Nofel Lagrosas, Dr. James Simpas

Abstract

Satellite Rainfall Validation and Assimilation Into a Weather Forecast Model Rainfall is an integral part of the Philippines’ climate. Many of its sectors rely heavily on adequate amounts of precipitation to function. However, recent events have also highlighted how excessive rainfall also affects severely the Philippines. Extreme weather events such as Ondoy and the more recent enhanced monsoon effect, Habagat, have shown how vulnerable the Philippines is to disproportionate amounts of rain. It thus becomes essential to either create or further develop current models to ensure that they have the capacity to predict these occurrences. For this reason, an assimilation technique is studied and used in this investigation to adjust the weather research and forecasting (WRF) model based on satellite-derived rainfall rates in order to improve the prediction of precipitation for these catastrophes. To implement this, two research objectives were formulated. The first is that satellite rainfall rates were validated for TRMM and CMORPH in order to determine the conditions where there are improvements in the accuracy of satellite data. Results showed that accuracy increases for higher rainfall amounts, making TRMM and CMORPH viable for these excessive rainfall events. Following this, the second objective is the improvement of precipitation forecasts through the adjustment of the mixing ratio based on the difference between satellite observations and initial forecasts. Findings show that immediately after forecasting, rainfall was captured more accurately and lower errors were noted post-assimilation.

MS Physics Thesis Defense: “Oblique angle deposition of Copper films on elastomeric gratings” by Artoni Ang

Oblique angle deposition of Copper films on elastomeric gratings

Name: Artoni Ang
Degree Program: M.S. in Physics
Thesis Defense Date: Thursday, 21 February 2013
Time: 6:00 pm
Venue: Faura 318
Adviser: Mr. Ivan Culaba
Department: Physics
School: School of Science and Engineering

Abstract:

Oblique angle deposition (OAD) has been used by several studies to change the property of the film by altering its nanostructure. In this study, oblique angle deposition was employed to reduce the buckling that result from the film deposition process. The surfaces of the films were observed before and during the application of stress. Prior to the application of stress, the samples deposited using conventional deposition exhibited buckles on their surface. The samples produced using OAD, on the other hand, did not exhibit any buckling. Upon the application of strain however, all samples eventually developed buckles that form perpendicular to the direction of the applied tensile stress. These buckles result in the decrease of the enhancement factor of the samples. The application of stress also resulted in the elongation of the diffraction grating. This increases the grating pitch of the samples and decreases the diffraction angle. However, in one of the samples produced, a columnar microstructure was observed on the film. The surface of this sample showed minimal buckling during the application of tensile strain, which caused a minimal decrease in the enhancement factor of this sample.

MS Physics Thesis Defense: “Analysis of the Reflectance Function for the Investigation of Biological Optical Filters” by Erika Aranas

The Department of Physics cordially invites you to the Thesis Defense of Ms. Erika Aranas on Monday, 11 February 2013, 3:00-5:00 pm, at Faura 318. Erika’s thesis adviser is Dr. Raphael Guerrero, coordinator of the Photonics Laboratory.

Title: Analysis of the Reflectance Function for the Investigation of Biological Optical Filters

Abstract:

Electromagnetic wave propagation in one-dimensional periodic media may be described using classical interference theory and modern photonic crystal theory. Both approaches may be employed in the investigation of laminated optical structures responsible for iridescence in beetles. Convergence of the two frameworks in the limit as the number of layers approach infinity is shown. Without relying on cumbersome absolute reflectance measurements and low-resolution micrographs, design parameter extraction was conducted based on angle-dependent peak wavelengths derived from relative reflectance experiments and other known parameters. In particular, the new band gap condition, formulated using the classical model, and the infinite layer approximation, facilitated the retrieval calculations.