Applied Mechanics and Materials Vol. 891

Abstract: Biomass fly ash is an ash combustion product. It is composed of the particulates (fine particles of fuel) driven out of biomass-fired boilers together with the flue gases. The understanding of the behaviour and property of fly ash is very important in order to predict the consumable part lifetime inside industrial boiler system. In this research study, the several characterization processes were carried out. It was revealed that biomass fly ash obtained from different sources presented unique property and more results were displayed in experimental result section.

Abstract: This research is a part of study of heat illness vulnerability. Understanding heat characteristic, especially in tropical area, would decrease loss from heat deceases and also support tourism in tropical countries. The aim of this research is to apply the meteorological sensor dataset in Chiangmai (a famous city in northern Thailand), which is under the control of Thai Meteorological Department, from 2015-2017 to investigate heat index characteristic. Two elements, temperature and relative humidity, were used to calculate heat index following Steadman’s equation. Analyzed heat index would be arranged by its intensity and then applied on heat illness warning. The study demonstrated that heat index warning from Automatic Weather Station data analysis could get along with the maximum temperature historical statistics data which observed by weather stations. Local people and visitors in Chiangmai mostly suffer from heat in between March and June. The greatest vulnerability to heat illness in Chiangmai was in April and May. This extreme-heat period is consistent with the report from Department of Decease Control Thailand, an amount of heat illness patients is very high in April and May. Moreover, the results show that even if the air temperature is getting low in after summer season but heat index is still high through the year. So, people still need to be aware of heat deceases and always concern about environmental heat when doing outdoor activities. In the future, AWS data from every station over Thailand would be used to develop a real-time Heat Illness Alert System.

Abstract: Water is a natural resource that is important for both human health and the environment. However, the routine activities of the municipal and industrial sectors can result in the contamination of water resources. The application of remote control water sampling is therefore useful for environmental field work by employing a remote control water sampler in a 700 m radius to collect three samples at once time during a sampling collection within 15 sec at various depths, including 0.50 m, 0.75 m and 1.00 m in depth, respectively (500 ml/sample). Remote control water sampling works with a water flow rate of 35.11±0.09 L/sec on average. For comparison, the performance of the remote control water sampling and a hand-held water sampler were evaluated. The basic water quality parameters involved temperature, pH, dissolved oxygen, total dissolved solids, electrical conductivity, and coliform bacteria were found in range of 30.1-30.3 °C, 6.1-6.4, 1.06-1.20 mg/L, 337.0-359.0 mg/L, 686.0-724.0 µS/cm, and 32.0-48.0 colony, respectively, which the results showed were mostly quite similar. This machine functions as an alternative water sampler and is useful for field work applications. Moreover, it provides many advantages, such as reduction of workers, cost benefits, time-savings, and reduction of health risks.

Abstract: The aim of this work was to validate the sample preparation using a microwave digestion for determination of total arsenic in a spiked soil. Graphite furnace atomic absorption spectrophotometer (GFAAS) technique was used to determine the total arsenic using palladium nitrate as a modifier agent. The instrumental detection was performed under the condition steps of drying, ashing, atomizing and cleaning to be 100, 1200, 2250 and 2600°C, respectively. The external calibration curve was constructed using the automatic program with the master standard of 20 ppb arsenic solution. It was found that linearity range was in the range of 1 to 20 ppb with R²>0.999. The LOD and LOQ were 0.10 and 1.0 ppb, respectively. Based on two microwave digestion programs, the total arsenic obtained from the preparation method with HF and without HF were also compared. The result showed that the arsenic content obtained from both methods did not significantly different at the 95% confidence limit. The percentage of recovery was 80.3 and 82.3% for the spiked samples of 2.5 and 10 ppb, respectively. The relative standard deviation was 2.15% (n=11). The results of this work confirm that the preparation method using microwave digestion provided the more advantages, such as rapid, a little volume of reagents, completely digestion.

Abstract: TThe aims of this research work were to improve touhgness and water resistance of wheat gluten (WG) by epoxidized natural rubber (ENR) compared to glycerol. WG specimens were mixed and prepared by internal mixer and compression molding machine, respectively. ENR and glycerol were varied from 10 to 40 wt%. Effects of modifier types and contents on WG were evaluated by tensile, impact and water absorption testings and microstructure and thermal analyses. The increase of ENR or glycerol contents led to the increase of toughness by considering the increase of impact strength and elongation at break. Glass transition temperature of WG tended to decrease with the increase of ENR or glycerol contents, especially for glycerol. The presence of glycerol affected to the decomposition temperature values whereas ENR did not affect to decomposition. ENR improved water resistant of WG specimen but trend of glycerol showed the opposite behavior. Weight loss of modified WG with glycerol was found at immersion time of 1440 min.

Abstract: Sulfonated graphene oxide (sGO) was used as a filler to enhance performance of sulfonated poly(ether ether ketone)(sPEEK) membrane. The sGO was firstly prepared by treating graphene oxides (GO) with sulfanilic acid at 70 °C for 20 h. The sGO was characterized by FTIR and XPS techniques. Composite membranes of various amount of sGO were fabricated via solution casting method. The properties of composite membranes were investigated by measuring ion exchange capacity (IEC), water uptake, ion conductivity and vanadium ion permeability. From the results, it was found that the IEC and water uptake of the membranes increased after adding the sGO. Ion conductivity of the sPEEK membrane also increased from 8.94*10^-3 Scm^-1 to 10.55*10^-3 Scm^-1. Moreover, permeability of vanadyl sulfate (VOSO₄) through the composite membranes were decreased. These composite membranes exhibit great potential for vanadium redox flow batteries application.

Abstract: This paper reported the effect of latex rubber (LR) and rubber powder (RP) on the bending strength of cement mortars containing fly ash silica (FAS) prepared from sugarcane bagasse. The bending strengths of the cement mortars with the addition of LR and RP were compared. The study was conducted by adding 5-10 wt% of each admixture into cement mortar specimens and left in air atmosphere for 28 days before measuring their bending strength. At 5 wt.%, both LR or RP could significantly reinforce the bending strength of the mortar. The bending strength of cement mortars decreased when the proportion of the LR and RP were higher than 5 wt%. In addition, at 10 wt%, LR provided better bending strength than that of RP, i.e. the bending strength of mortar contained LR was 550 ksc, whereas that contained RP was 85 ksc. The bending strength of mortar with LP was much higher than that of the pure cement mortar (20 wt% FAS : 80 wt% cement) which was about 62 ksc. The low bending strength of the mortar with 10 wt% RP may be due to the decrease of Si-O-Si hybrid compounds which was inhibited by the hydroxyl group during the hydrolyzation process.

Abstract: Thermoplastic polyvinyl chloride (PVC) is one of the most widely used polymers in the world. Due to its versatile nature, PVC is used extensively across a broad range of industrial, technical and everyday applications including widespread use in building, transport, packaging, electrical/electronic and healthcare applications. In this study, thermal spray technology was used to apply PVC powder on metal substrate. It was revealed that the spray parameters such as working distance, preheat and flame temperature played the important role on the properties of PVC coating.

Abstract: According to their wonderful properties, carbon nanotubes (CNTs) have been well known for decades. The synthesis process and catalyst deposition method have also drawn attention to control the nanotube structure and properties. Sputtering method is then one promising option to grow the nanotubes in mass production. This method is, however, still costly. Here, we have presented a simple low-cost custom-made DC magnetron sputtering for catalyst thin film deposition. Three different metal thin films (Fe, Ni, Cu) deposited on Si substrates have been employed to investigate nanotube production. Prior to deposition of the catalysts, Al was used as supporting layer. (Al/Fe, Al/Ni, Al/Cu). CNTs were grown by chemical vapor deposition process at 800°C. Ethanol was preliminary used as a carbon source. It was found that CNTs could be successfully grown from only Al/Ni catalysts in our system with the diameter of approximately 200 nm, where the rest of samples were not observed. In addition, vertical-aligned CNTs with the thickness of about 10 μm could be obtained when acetylene was replaced instead of ethanol with reducing partial pressure of the feedstock. A large D-band at 1338 cm^-1 with broader G-band at 1582 cm^-1 from Raman spectra give a rise to multi layers growth of sp² carbon walls. Such dimension suggests that it is the characteristic of multi-walled carbon nanotubes.

Abstract: Cerium oxide and tin oxide nanocomposites (CeO₂-SnO₂ NCs) were successfully synthesized via a simple co-precipitation method. The structure and properties of the synthesized materials were characterized using several X-ray and electron-based techniques including XRD, FE-SEM, TEM, EDS and BET to unravel the structure, morphology, element composition and specific surface area. The XRD and BET results showed that the NCs have the characteristic crystalline structures of SnO₂ and CeO₂-SnO₂ NCs, and high specific surface area (66.45 and 86.29 m²/g), respectively. Amorphous phase of CeO₂ and SnO₂ were not found in XRD patterns. EDS analysis confirms the absence of all element composition and the FE-SEM and TEM analysis observed as particles having the clear spherical morphologies with the average particle size of of SnO₂ and CeO₂-SnO₂ NCs was about 13 and 10 nm, respectively.