This paper aims to develop a Graphical Footprint Model (GFM) that will validate radio frequency (RF) energy harvesting capabilities of radio frequency (RF) energy sources, such as frequency modulation (FM), television (TV), and cellular technology (Cell) for validation of RF at different classified multiple urban settings. The GFM is composed of scoring scheme for energy capabilities, which is based on a -20dBm and up of Power Received Levels (PRL) at different classified multiple urban settings, which includes Line of Sight (LOS), Rural (R), Suburban (S), Urban High (UH), Urban Very High (UVH), and Non-Line of Sight (NLOS) settings. The Communications Engineering Formula Budget link was used to get the PRL for RF potentials in dBm, to determine the classified multi-settings together with the RF sources for RF harvesting capabilities.

In establishing a benchmark for the GFM, a review of twenty one research studies was undertaken for data analytics. The result of the exercise showed a percentage acceptability range of 84.00 % with a Mean Square Error (MSE) of 14 along a mean average distance accuracy range of 1451 meters. To determine whether the GFM can predict heuristically with the use of a weighted mean, the analysis covered spread-out data points over a large range of values, considering a standard deviation of 3091. The grand mean obtained was an intensity score of 3, with the initial voltage range from 70mV to 125 mV. This is a very good level for GFM to predict heuristically the RF potential.

In a classified Line of sight multiple setting area, the farthest average distance radius of RF energy potentials from television (TV), frequency modulation (FM), and cell sources are 2768, 2175, and 127 meters respectively, with an intensity score of 1 (Fair level with an initial voltage of 22mV to 40mV for RF potential). On the other hand, in a classified Urban Very High (UVH) multiple setting, the farthest distance for RF potential from a TV source is 1110 meters, from FM source at 950 meters and from a cell source at 76 meters, all with an intensity score of 1. Through the GMF, farthest point as well as the nearest point for RF potential, its corresponding scores, initial voltages and powers can be determined.

The GFM will benefit future design engineers and installers of RF harvesters. GFM can provide them the necessary information to determine the locations and distances for RF potential emitted from FM, TV, and Cell energy sources in different classified multiple settings. GFM serves as a smart and useful tool for design considerations of RF harvester modules that have application in Internet of Things (IoT) and other devices that need only a minimal amount of power.

Recent studies have focused on the detrimental effects of earthquakes on the bearing capacity of shallow foundations. According to Terzaghi’s classical theory, the bearing capacity of a shallow strip foundation is the superposition of three contributing factors, namely, the cohesion of the soil (Nc), the unit weight of the soil (Nγ), and the soil surcharge (Nq). The kinematic element method (KEM) based on the upper-bound limit analysis theory has shown potential in solving soil stability problems through simple kinematics, statics, and optimization. This research aims to assess the static and seismic bearing capacity of shallow strip foundations using the kinematic element method – particle swarm optimization (KEM-PSO) along with the traditional pseudo-static approach, comparing the results with the Analysis of Bearing Capacity (ABC) program, and existing literature solutions. Additionally, the study investigates the validity of the superposition of effects principle by comparing separate soil and superstructure inertia with the combination of the two. The results reveal an overestimation of the static bearing capacity factor Nγ but a negligible difference for Nq and Nc compared to the ABC program. The discrepancy is attributed to the limitations of the KEM in considering the distribution of stresses within the soil mass surrounding the foundation and in discretizing the failure mechanism. Similarly, the seismic bearing capacity factors Nγ and Nq are overestimated. The study proposes quadratic and bi-quadratic correction factors for the static and seismic cases using the Levenberg-Marquardt non-linear least squares methods. The corrected values align well with the available literature solutions. Thus, KEM-PSO and the correction factor functions can serve as a design tool for shallow strip foundations' static and seismic bearing capacity. The study validates the superposition of the inertia effects principle, enabling different seismic loads assigned to the soil and superstructure.

Desorption and back diffusion of a chlorinated solvent such as trichloroethylene (TCE) from the low permeability zone (LPZ) to the transmissive zone in the subsurface exhibits a challenge in remediation. The study was to investigate the in situ chemical oxidation (ISCO) using a sodium persulfate sustained-release rod (SPS SR-rod) for potential remediation application of TCE contamination in the LPZ within a two-dimensional sand tank. The objective was to determine the SPS concentration distribution contour when placing the SPS SR-rod atop and within the LPZ. A laboratory scale, 2D tank system (100 cm L x 5 cm W x 50 cm H) represents a distinct type of LPZ in the geologic settings, exhibiting a saturated dual permeability porous media. The SPS SR-rod placed within the LPZ released an average ~625 mg L-1 concentration contour from at least 10 to 15 cm lateral distance from the rod. When the rod placement was atop LPZ, continuous determination of persulfate concentrations at an average value of ~57 mg L-1 within the LPZ was observed comparably at low and high hydraulic gradients of 0.01 and 0.05, respectively. A separate evaluation of both SPS SR-rod placements in the 2D sand tank injected with pure TCE is conducted to test if the oxidant perfusion can address the difficulties in destroying soil-sorbed TCE. It took five days for sorption-desorption from the injection point to occur. On the 10th and 15th days, the concentrations of TCE exceed the groundwater limit of 0.05 mg L-1 set by Taiwan. Comparably lower concentrations are observed in the HPZ following back diffusion and concentration gradient principles where lower mass flux results in lower resultant aqueous concentration. In the presence of an SPS SR-rod, TCE concentration measures up to 0.6 mg L-1 versus 1.4 mg L-1 when no SPS rod is present. The persistence of persulfate in the LPZ and its slow release in the subsurface supports that the SPS SR-rod may be an efficiently controlled release material in extending the ISCO remediation of TCE in low-concentration scenarios in LPZ and its surrounding environment. This approach allows for efficient and effective remediation and limited loss of oxidant mass during delivery while minimizing the risk of adverse effects or excessive chemical usage.

Titanium dioxide (TiO2) is an n-type semiconductor that is commonly used as an optoelectronic material due to its high stability. These applications include as photocatalysts and as photovoltaic devices. However, TiO2 has poor absorption in the
visible-light region. Hence, to improve its visible light sensitivity, TiO2 can be doped with nitrogen (N). Doping TiO2 with N also exhibits p-type conductivity.
Tin oxide (SnO2) is an n-type semiconductor that is also used as an optoelectronic material. Coupled together, the two can form a heterojunction. In this study, 120-nm thick SnO2 films are deposited on 250-nm thick N-doped TiO2 films grown on silicon dioxide substrates. N-doped TiO2 is produced by reactive sputter deposition of titanium nitride (TiN) films with post-deposition annealing.
Grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy confirmed the formation of N-doped TiO2 when TiN is annealed at 450◦C. Interstitial doping was considered to be the major doping mechanism. UV-vis spectral analysis showed an increase in absorbance in the visible light region with a shift in the optical band gap from 3.33 eV for TiN to 2.51 eV for N-doped TiO2. Hall effect measurements revealed TiN and N-doped TiO2 film resistivities on the order of 10−4 Ω-cm. Carrier densities are on the order of 1021 cm−3. Carrier mobilities up to around 45 cm2 V−1 s−1. Sheet resistances below 6 Ω sq−1. For annealed SnO2 film, resistivity was around 0.091 Ω-cm, electron carrier density of around 1019 cm−3, carrier mobility around 2 cm2 V−1 s−1, and sheet resistance around 8000 Ω sq−1. The current-voltage characteristic of the SnO2-N-doped TiO2 heterojunction thin films exhibited a rectifying behavior under dark and light illumination.

Diesel power plants have dominated the Philippine’s off-grid electrification, primarily due to the immensely high cost and intricate level of difficulty associated with interconnecting the different remote islands on the central grid in the mainland to supply power. This circumstance has resulted in an unreliable, costly, and environmentally detrimental provision of electricity across the majority of the country's secluded islands. The use of renewable or hybrid renewable energy systems (RES or HRES) and energy storage systems (ESS) is rapidly becoming a viable alternative in remote area electrification as it provides a more sustainable and cleaner source of energy. This study proposes an optimal energy system transition using solar PV system, battery energy storage system (BESS), and hydrogen energy storage system (HESS) to be integrated with the existing energy system of two case study island resorts in Malapascua Island, Cebu (Case Study 1) and Boracay Island, Aklan (Case Study 2) in the Philippines. Site-specific parameters, such as roof orientation, available active area, and nearby shading, were incorporated in the RE system model using PVsyst software that yielded the maximum available installed capacity and hourly effective output of the solar PV system. Using HOMER Pro software, the optimal capacity of the solar PV system and ESS components to operate with the existing energy system was computed based on the least levelized cost of electricity (LCOE). Post-simulation analysis employs a Weighted Sum Model (WSM) to integrate other essential energy system criteria, such as system cost, reliability, and sustainability, that align with the preferences of resort management. Energy system optimization results reveal the HRES configuration, employing Solar PV/BESS/Grid/Diesel Generator, as the system alternative with lowest LCOE for both CS1 and CS2 island resorts, registering 0.2937 $/kWh and 0.2582 $/kWh, respectively. This equates to an improvement of 7.5% for CS1 and 0.769% for CS2 when compared to the current establishment’s LCOE. The outcomes of the post-simulation analysis sustained the top-ranking system identified by HOMER Pro. The WSM results favored the same HRES setup as the preferred choice in both CS1 and CS2 resorts, with overall preference scores of 71.09 and 83.60, respectively. The subsequent sensitivity analysis also supported the adoption of the HRES configuration as it consistently emerged as the superior alternative, exhibiting high normalized preference scores and favorable LCOE across nearly all sensitivity scenarios, covering three critical parameters involving projected variations in costs of external energy sources, solar PV system components, and energy storage components that were analyzed in both case studies.