The Philippines, with its numerous off-grid islands, face challenges in reliable and affordable electricity supply. Currently, at least 132 small islands and isolated grids (SIIGs) depend on oil-based generators, resulting in high cost, unreliable, and inadequate power, which negatively impacts living standards, education, public health, and economic opportunities. This thesis developed a methodology for determining the least-cost voltage and timing of interconnecting island grids to the main grid. It compares the cost effectiveness of connecting to the main grid with that of continuing with oil-based generators with RE-based hybrid system. The interconnection scenario assesses the route and voltage level options for the least-cost interconnection scheme which is compared with the least-cost RE-based hybridization capacity expansion plan of continuing isolated island grid. The goal is to identify the most cost-effective solution including timing for improving power supply reliability and affordability for island grid interconnection in the Philippines. The methodology is applied to a case study of an interconnection of an off-grid island.

Silver nanoparticles (AgNPs) have been extensively studied in the biomedical field for cancer therapy and drug delivery applications due to their unique physicochemical properties. However, most studies in drug delivery applications report AgNPs synthesized using the chemical route, which involves toxic and costly reagents. To provide a safer and more cost-effective alternative, several studies have utilized biological resources and by-products to synthesize AgNPs mainly for antimicrobial and anticancer activities, but most of them lack insights on drug delivery capabilities. This study explored the sustainable synthesis of silver nanoparticles (AgNPs) using rice straw, an abundant agricultural waste product in the Philippines, and evaluated its potential drug delivery applications in liver cancer treatment by conjugating it with a chemotherapy drug, Epirubicin (EPI). AgNPs were synthesized using rice straw extracts acting as both the reducing and stabilizing agents, and results were confirmed through UV-Vis spectroscopy showing a spectral peak at 392 nm under specific conditions: 140 minutes reaction time, 14 mg/mL rice straw extract, and 6 mM AgNO3. The resulting AgNPs exhibited stable physicochemical properties, including a negative zeta potential (-31.5 ± 1.53 mV), ensuring colloidal stability and long-term storage suitable for biomedical drug delivery applications. Dynamic Light Scattering (DLS) analysis confirmed successful conjugation of the synthesized AgNPs with EPI with the hydrodynamic diameter increasing from 202.4 ± 34.38 nm (for unconjugated AgNPs) to 329.1 ± 6.732 nm for AgNP-EPI. The encapsulation efficiency (43.32% ± 0.0593) demonstrated the ability of the synthesized AgNPs to carry sufficient drug payloads, a critical factor in achieving effective therapeutic concentrations while minimizing the frequency of administration. Drug release kinetic studies revealed a controlled dual release mechanism involving diffusion and erosion, as supported by Weibull (R²_adj=0.9540), Korsmeyer-Peppas (R²_adj=0.9323), and Higuchi (R²_adj=0.9299) models, with approximately 33.68% of the encapsulated EPI released over an 8-hour dialysis experiment. This release profile supports sustained drug release, which is essential for maintaining therapeutic concentrations at the target site over an extended period, while reducing the risk of rapid systemic exposure, which can lead to toxicity. Lastly, initial cytotoxicity assessments using HepG2 liver cancer cells was also conducted to determine potential applications in cancer therapy.

This study aimed to address the problem of discriminating not only among general
benthic cover classes but also between coral mortality states using image
classification. More importantly patterns in phase shifts of coral reef environments
were studied using post-classification change detection and spatial analysis to
determine which directions of change were most prevalent in the study areas, at
what exact locations they occurred, and what factors may have contributed to the
change.

Maximum likelihood classification was used to classify the 1988-1989 and 1999-1999
image mosaics into live coral, dead coral, rubble, sand, seagrass, and short
seagrass, yielding overall accuracies of 71.61% and 78.59%, respectively. It was
evident from the results of the post-classification change detection that corals and
mangroves have undergone significant degradation and about 18% of the entire
area underwent negative phase shift. Overall, the islands of Tangkahan, Pulao Bato,
and Unok have been determined to be change hotspots, based on the comparison of
percentages of negative and positive changes. All islands except the southern tip of
Palawan mainland have been identified as mangrove hotspots, and Bancalaan,
Malinsono, Pandanan, Patonggong, Pulao Bato, Tangkahan, and Unok were
identified as coral hotspots. Among the correlations performed, the analysis
between the type of threat and type of negative change yielded the most realistic
and informative results.

With the outputs from this study, concerned parties or individuals would know
where immediate action is needed. Furthermore, if there is a time series of this
type of information, the rate and trend of degradation may be analyzed to come up
with more effective solutions to the problem and timely mitigation measures. With
the availability of more detailed, accurate, and complete data, a better correlation
between the identified hotspots in this study and possible change factors may be
possible.

Prussian blue (PB) and its analogues (PBA) are promising materials for sodium-ion batteries (SIBs) due to its sturdy and open framework which accommodates volume change and allow fast diffusion of Na+ during battery cycling. Particularly, fully-sodiated Mn-based Prussian White (PW, Na2Mn[Fe(CN)6]) can have high Na+ concentration in the framework allowing the employment of simpler and cheaper non-sodium-based anode, hence, better scalability and commerciality. However, the Jahn-Teller effect of Mn3+ causes structural deformation in PW, resulting in significant volume changes and deteriorating cycle performance. While period 4 transition metal atoms (e.g., Ni, Cu, Zn) have been extensively explored as dopants to improve the cycling stability of PWs, the effect of other metal dopants such as silver (Ag) remains largely unexplored. Herein, various amounts of Ag were introduced to manganese hexacyanoferrate framework (Na2+xAgxMn1-x[Fe(CN)₆]·nH2O; x = 0 – 0.15) through a facile coprecipitation method. The material properties of the compounds were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, Scanning Electron microscopy and Transmission Electron Microscopy with Energy-Dispersive X-ray spectroscopy (SEM-EDS, TEM-EDS), Thermogravimetric Analysis (TGA), C,H,N elemental analysis, and Brunauer-Emmett-Teller (BET) surface area measurements. Electrochemical performance evaluations in half-cell configurations show that doping Mn with 10 mol% Ag resulted in the best overall electrochemical performance among the synthesized PW materials. This concentration delivered a superior rate performance obtaining 70.76 mAh g-1 at 5C, equivalent to 49.85% of its initial capacity (141.94 mAh g-1) at 0.1C (1C = 170 mAh g-1) which is superior to the undoped PW (37% capacity obtained at 5C). It also exhibited an excellent long-term cycling performance with 54.73% capacity retention after 100 cycles at 1C (vs. 46.41% in the undoped PW) and had less overpotential (ΔE = 165 mV) compared to the undoped material (ΔE = 295 mV). The improved electrochemical performance at this doping level can be attributed to the decreased charge transfer resistance (771.5 Ω vs the undoped sample: 1927 Ω), and an increased Na+ diffusion coefficient as obtained from the Electrochemical Impedance Spectroscopy (EIS) measurements. This is due to the structural regulation brought by Ag doping, as corroborated by a leftward peak shift in XRD results associated with an increased lattice parameter, making it easier for Na+ de-/intercalation in the PW material during cycling. Furthermore, it was revealed that 10 mol% Ag doping is the optimal amount, with a lower amount (5 mol% Ag) being insufficient to stabilize the structure, and excessive doping (15 mol% Ag) compromising the structural stability and performance. This study investigates the role of Ag doping in improving the structural and electrochemical properties of PW compounds, making them a promising cathode material for SIBs. Additional material characterization and electrochemical performance evaluation techniques are suggested to further understand the material's structural evolution, composition, and electrochemical behavior.

The QR code Mobile Payment (QRMP) system is being introduced into tricycle operations in various cities across the Philippines. Since the current literature lacks a comprehensive understanding of its adoption in paratransit services such as tricycles, this study aims to address this gap by investigating QRMP adoption in tricycle operations in Antipolo City, focusing on user acceptance, potential benefits, and challenges from drivers' and passengers' perspectives. A theoretical framework combining Task-Technology Fit (TTF) and the Unified Theory of Acceptance and Use of Technology (UTAUT2), extended by Perceived Risk and Financial Inclusion, was used to examine user acceptance. For analysis, PLS-SEM was used. The study also evaluated how QRMP usage could influence passengers' choice of tricycles as transport mode, improve fare collection, and facilitate quicker alighting from vehicles. The empirical findings revealed that the critical factors driving QRMP adoption among passengers include Effort Expectancy, Task-Technology Fit, Social Influence, Price Value, and Financial Inclusion. For drivers, the significant factors are Performance Expectancy, Social Influence, Price Value, and Task-Technology Fit. It was also found that the price value of QRMP has a bigger impact on younger passengers' decision to use QRMP than on older passengers. While most passengers believe that QRMP enhances their ride experience, drivers only recognize some benefits. Both
groups, however, perceived common challenges, such as poor internet connectivity and app malfunctions.