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A Zero-dimensional Mathematical Model of PM2.5 Measurement due to Daily Vehicle Density in Bangkok
(2025-05-01)
Khum-Un, Seree
;
Pochai, Nopparat
Air pollution, particularly particulate matter smaller than 2.5 microns (PM2.5), has grown to be a serious issue that has an impact on people's health, especially the respiratory system. There are several studies that have found that the level of PM2.5 in the Bangkok region is high, as is how it affects individuals with respiratory illnesses. In this research, a numerical simulation of PM2.5 concentration was performed using a zero-dimensional model of PM2.5 measurement due to the daily vehicle density in Bangkok. It is evident that the wind speed and daily vehicle density have an impact on the simulated PM2.5 concentration in Bangkok. The daily density of vehicles greatly influences PM2.5 emissions. Wind speed was measured in this experiment. The hourly vehicle density in Bangkok, which was represented by calculating functions for wind speed and PM2.5 emission rate, is what produces the computed PM2.5 emission rate. The simulation includes three 24-hour scenarios: low vehicle density with medium wind speed, high vehicle density with low wind speed, and medium vehicle density with high wind speed. All of the models indicated that the PM2.5 level would drop as wind speed increased and vehicle density decreased. The daily vehicle density and wind speed are two factors that affect the PM2.5 level. Focusing, especially on wind speed, will not always lead to PM2.5 reductions. However, daily vehicle density also has a significant role in PM2.5 management. Wind speed and vehicle density influence PM2.5 concentrations, with three scenarios demonstrating that higher wind speed and lower vehicle density reduce PM2.5 levels. While wind speed helps to reduce PM2.5 levels, vehicle density also has a substantial impact on emissions. Managing PM2.5 requires addressing both daily vehicle density and wind speed, as focusing on only wind speed may not always result in reductions.
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A Shoreline Evolution Model with Wave Crest Model on I-Head and T-Head Groin Structures with Different Types of Breaking Wave
(2024-06-01)
Unyapoti, Pidok
;
Pochai, Nopparat
Beach erosion is a process that results in changes to the materials of a shoreline, with erosion being the removal of material from the shoreline more than its addition. Beach erosion on the shorelines causes loss of landforms and a reduction in size, leading to the need for the development of various structures to mitigate beach erosion. Groin is one of the commonly utilized structures for coastal erosion prevention, and groins of various shapes and forms have been developed to minimize beach erosion to the greatest extent possible. We have focused on assessing the impacts of I-head and T-head groin structures on shoreline evolution, approximated through a shoreline evolution model. Various techniques for setting initial conditions and boundary conditions have been discussed. Additionally, we have explored the structural impacts of these two groin types. We considered the average wave crest impact angle obtained from a wave crest impact model on both the left and right sides of the shoreline, differing over a span of four wavelengths. To estimate shoreline evolution for each year, we employed traditional forward time-centered space techniques and the unconditionally stable Saulyev finite differential techniques. The results of shoreline evolution calculations for both groin structures were found to be consistent across the four cases of the wave crest impact model.
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An Unconditionally Stable Explicit Finite Difference Method for a Non-Dimensional Mathematical Model of Shoreline Evolution with a Twin Groins Structure
(2024-02-01)
Manilam, Surasak
;
Pochai, Nopparat
The development of a more effective model and the prediction of trends in shorelines were the two goals of this study. For simulations of shoreline evolution utilizing the straight twin groin structure, we used two mathematical models. A one-dimensional evolution model makes up the initial model. The first model is transformed into a non-dimensional evolution model in the second model. We propose a method for transforming one-dimensional models into non-dimensional models, that involves creating initial and boundary conditions for each model. The forward time centered space (FTCS) technique and the Saulyev finite difference technique were applied to approximately represent shoreline evolution each year. Their simulation results demonstrate that when the engineering structure was built on the nearby shorelines, shoreline evolution accelerated annually. As the Saulyev finite difference technique is not restricted by the stability conditions, it produces better simulations.
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A Combination of A Shoreline Evolution Model and A Wave Crest Model on T-Head Groin Structures With the Breaking Wave Effecf
(2023-01-01)
Unyapoti, Pidok
;
Pochai, Nopparat
Beach erosion is a naturally occurring phenomenon that occurs when the transfer of material away from the beach is not balanced by the deposit of new material on the shoreline. Beach erosion have always existed and have influenced the shoreline shape. This is a problem that contributes to the loss of shorelines. Structures invented to prevent beach erosion, such as seawalls, groins, and breakwaters. To avoid coastal erosion and sedimentation, a groin and a sea wall were constructed. Shoreline evolution analysis is being used to research the future topography of the beach. Beach erosion and beach deposition research requires a qualitative analysis of the model shoreline behavior with respect to the driving process. In this research, we focus on the effects of the T-head groin structure on shoreline evolution. The average wave crest impact is analyzed for eight sizes of T-head groin construction. An initial condition setting technique and boundary conditions techniques, as well as the structural impacts of the T-head groin, are discussed. Each year, the shoreline evolution is approximated using the traditional forward time centered space techniques and the unconditionally stable Saulyev finite differential techniques. The calculated impacts of shoreline evolution for eight different T-head groin sizes were consistent with the wave crest impact model.

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