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Integrated Urban Transport and Land-Use Policies in Reducing CO2 Emissions and Energy Consumption: Case Study of a Medium-Sized City in Thailand
(2024-08-01)
Chindaprasirt, Prinya
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Klungboonkrong, Pongrid
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Jaensirisak, Sittha
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Faiboun, Natthapoj
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Long, Sina
In developing cities, transport activities have become one of the primary sources of CO<inf>2</inf> emissions and energy consumption owing to rapid economic growth, urbanization, and motorization. Khon Kaen City, Thailand, was chosen as a representative mid-sized city of a developing country to investigate the potential influences of transit-oriented development (TOD), light rail transit (LRT), and electric vehicle (EV) policy integration scenarios on CO<inf>2</inf> emission and energy consumption reductions in 2016, 2026, and 2046. The TOD did not significantly reduce CO<inf>2</inf> emissions or energy consumption because it was only applied in one area of the city. The LRT development also had a small effect because of the small proportion of modal shifts to LRT. However, EV utilization offered the greatest potential for reducing both CO<inf>2</inf> emissions and energy consumption. In addition, the integrated scenario combining the three policies had a promising effect, diminishing both CO<inf>2</inf> emissions and energy consumption, because it gathered the potential merits and benefits of each individual policy.
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Use of viscoelastic polymer sheet as an acoustic control treatment in ceramic tiles to improve sound insertion loss
(2023-03-01)
Sukontasukkul, Piti
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Tontiwattanakul, Khemapat
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Puttiwongrak, Avirut
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Zhang, Hexin
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Parichatprecha, Rattapoohm
Ceramic tiles are commonly used in non-structural components of a building such as walls, partitions, floors, and roofs. However, due to their high surface hardness and density, ceramic tiles are not an ideal soundproof material. To improve the sound properties, this study introduced the use of a viscoelastic polymer sheet (VPS) as an acoustic control treatment. The VPS was attached to ceramic tiles in 4 different patterns: X, Cross, Corner, and Strip. The ceramic tiles with VPS were tested for the damping property and sound insertion loss (IL) and then compared to the ones without VPS. Results indicated that the attachment of VPS improved the damping property of the ceramic tiles. All tiles with VPS exhibited higher damping loss indexes than the ones with no VPS. The highest damping loss index of 0.017–0.018 was observed in the specimens with VPS in X and Cross patterns. In the case of IL, the performance of all ceramic tiles was indifferent when tested at sound frequencies smaller than 1000 Hz. At the sound frequencies above 1000 Hz, the best performance was observed in the specimen with VPS in the Cross pattern, followed by X, Strip, and Corner patterns, respectively. This concluded that the use of VPS can improve the damping property of a ceramic tile which also leads to the improvement in sound insertion loss.
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Effect of graphene oxide on single fiber pullout behavior
(2021-04-19)
Chindaprasirt, Prinya
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Sukontasukkul, Piti
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Techaphatthanakon, Apisit
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Kongtun, Suriyawan
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Ruttanapun, Chesta
The properties of fiber reinforced concrete (FRC) depends strongly on bond between fiber and cement matrix. Any change in matrix and fiber characteristics affects the bond behavior. In this study, the effect of graphene oxide on cement composite strength and bond behavior between fiber and cement matrix was investigated. The graphene oxide solution with concentration of 10 mg/ml was mixed with cement mortar at 0.05% by weight of cement. Four types of fibers viz., hooked end steel, double hooked end steel, polypropylene and glass fibers were tested by embedding in both plain cement mortar (M) and cement graphene mortar (GM). The single fiber pullout test was performed at the rates of 60 and 180 mm/min. Results were collected in form of failure mode, scanning electron microscope (SEM) images, bond-slip response, bond strength and energy absorption. SEM images showed that the failure modes depended on fiber type, matrix type and loading rate. The steel fibers showed almost no damage except for the change of hooked end shape at the fiber end. For polypropylene fiber, the fiber surface scraping was commonly observed while the debonding of coating material was observed for glass fiber. The bond strength was higher in GM mortar than that of M mortar and increased with the increase in loading rate. In the case of fiber type, steel fibers exhibited higher bond and energy absorption than both polypropylene and glass fibers.
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Effect of free oxygen radical anions and free electrons in a Ca12Al14O33 cement structure on its optical, electronic and antibacterial properties
(2019-05-01)
Phrompet, Chaiwat
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Sriwong, Chaval
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Srepusharawoot, Pornjuk
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Maensiri, Santi
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Chindaprasirt, Prinya
The aim of this work was to investigate the effect of free oxygen radicals and free electrons in a Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> (C12A7) cement structure on the optical, electronic and antibacterial activity of this material. Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> was successfully fabricated via rapid heating to high temperatures by high frequency electromagnetic induction. Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> cement samples were characterized using XRD and UV-Vis-DRS spectroscopy. The morphology and chemical composition of the samples were also investigated using SEM and EDS techniques. The presence of free oxygen radicals (O<inf>2</inf> −ions) in the insulating structure of Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> was confirmed using Raman spectroscopy showing a spectrum peak at 1067 cm−1. The excitation of free electrons in the Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> cement was indicated by UV-Vis absorption spectra at 2.8 eV and an optical energy gap of 3.5 eV, which is consistent with the first-principles calculations for the band energy level. The effects of free oxygen radicals and free electrons in the Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> structure as antibacterial agents against Escherichia Coli (E. coli) and Staphylococcus Aureus (S. aureus) were investigated using an agar disk-diffusion method. The presence of O<inf>2</inf> − anions as a reactive oxygen species (ROS) at the surface of Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> caused inhibition of E. coli and S. aureus cells. The free electrons in the conducting C12A7 reacted with O<inf>2</inf> gas to produce ROS, specifically super oxides (O<inf>2</inf> −), superoxide radicals (O<inf>2</inf> •-), hydroxyl radicals (OH•) and hydrogen peroxide (H<inf>2</inf>O<inf>2</inf>), which exhibited antibacterial properties. Both mechanisms were active against bacteria without effects from nano-particle sized materials and photocatalytic activity. The experimental results showed that the production of ROS from free electrons was greater than that of the free O<inf>2</inf> − anions in the structure of Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf>. The antibacterial actions for insulating and conducting Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> were different for E. coli and S. aureus. Thus, Ca<inf>12</inf>Al<inf>14</inf>O<inf>33</inf> cement has antibacterial properties that do not require the presence of nano-particle sizes materials or photocatalysis.
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Optical and dielectric properties of nano-sized tricalcium aluminate hexahydrate (C3AH6) cement
(2018-08-10)
Phrompet, Chaiwat
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Sriwong, Chaval
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Maensiri, Santi
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Chindaprasirt, Prinya
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Ruttanapun, Chesta
The present study investigates the optical and dielectric properties of nano-sized C3AH6 cement hydrates. A cement product was fabricated via a simple hydration process using a derivative of a C12A7 cement precursor reacting with de-ionized water while raising the reaction temperature to 100 °C. A crystalline phase of the C3AH6 cement product was characterized and confirmed using an XRD technique. Its morphology was also evaluated using TEM and SEM techniques. It was found that nano-sized C3AH6 (in size 10–50 nm) was successfully derived via this process. This cement product was thermodynamically stable over the range of room temperature to 300 °C. The optical direct gap was 4.1 eV and the indirect energy gap was 2.45 eV. Over the range of 20 Hz to 2 MHz, the observed capacitance was 10−10 F–10−11 F and the dielectric constant varied from 20 to 150. The dielectric properties were enhanced over those of general cement compounds. This effect was due to its complex structure in which –O–H bonding appeared in the structure and the formation of nano-sized structures from this process. These results suggested that the nano-C3AH6 hydrated particles were transparent to visible light and exhibited a high frequency electrical response. This implies an important role for these cement-based materials as potential candidates having optical and dielectric properties appropriate for applications such as smart building materials in the form of transparent electrode windows, smart wall capacitors, triboelectric devices and supercapacitors.

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