Now showing 1 - 7 of 7
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Classification of saline water for irrigated agriculture using near infrared spectroscopy coupled with pattern recognition techniques
    (2019-09-24) ;
    Phuphanutada, Jirawat
    ;
    This research aimed to create near infrared (NIR) spectroscopy models for the classification of saline water with a pattern recognition technique. A total of 112 water samples were collected from the Tha Chin river basin in Thailand. Water samples with salinity less than 0.2 g/l were identified as suitable for agriculture, while water samples with salinity higher than 0.2 g/l were found to be unsuitable. The NIR spectra of water samples were recorded using a Fourier transform (FT) NIR spectrometer in the wavenumber of 12,500-4,000 cm<sup>-1</sup>. The salinity of each water sample was analysed by electrical conductivity meter. Identification models were established with 5 supervised pattern recognition techniques including k-nearest neighbour (k-NN), support vector machine (SVM), artificial neural network (ANN), soft independent modelling of class analogies (SIMCA), and partial least squares-discriminant analysis (PLS-DA). The performance of the NIR model was carried out with a split-test method. About 80% of spectra (90 spectra) were randomly selected to develop the classification models. After model development, the NIR spectroscopy models were used to classify the categories of the remaining samples (22 samples). The ANN model showed the highest performance for classifying saline water with precision, recall, F-measure and accuracy of 84.6%, 100.0%, 91.7% and 90.9%, respectively. Other techniques presented satisfactory classification results with accuracy greater than 68.2%. This point indicated that NIR spectroscopy coupled with the pattern recognition technique could be applied to classify saline water for agricultural use according to salinity level in natural resources.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    A study of atrazine adsorption by using the rice straw synthesized adsorbent
    (2018-08-14) ;
    Deetae, Pawinee
    ;
    This study focused on adsorption of atrazine in adsorbent synthesized from Rice Straw. Rice Straw biochar were used in the study as they exhibited significantly high adsorption capacity for pesticide. Briefly, rice straw was pyrolysis at 600°C under nitrogen then biochar was modified using H<inf>3</inf>PO<inf>4</inf>. Biochar were characterized for their physico-chemical characteristics. The elemental analysis of biochar was performed using CHNS Analysis. The surface area and pore volume of adsorbents were estimated using the Brunauer, Emmett, and Teller (BET Analysis). In parts of Batch adsorption experiments was performed in range of room temperature and were divided to 2 parts. Part 1: Study of the kinetics adsorption was investigated using two models, namely, the pseudo-first-order and the pseudo-second-order models. Part 2: study of Adsorption isotherms. The results of CHNS analysis shows the elemental analysis that 51.795% of C, 0.763% of H, 1.634% of N and 0.654 % of S and the result of BET Analysis shows the surface area is 372.4 m<sup>2</sup>/g and pore volume of adsorbents is 0.315 cm<sup>3</sup>. From plotting between qt(mg/g) and time (t) shows the dynamics of the adsorption of atrazine onto the biochar at 15 ppm of initial atrazine concentrations. In general, atrazine was adsorbed quickly around 1-30 min. This could be due to fast mass transfer of solute from the solution to surface of adsorbent s as a result of concentration gradient of the solute. The study of the kinetics adsorption showed that the pseudo-second-order model best described the adsorption which agrees with chemisorption as the rate controlling mechanism.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Mathematical optimization of the anti-corrosive rice husk ash enhanced concrete under marine environment
    Chloride induced steel corrosion causes safety and stability problems to the reinforced concrete structure located closed to or under marine environment. The corrosive steel rust could potentially lead to surface swelling altering the external appearance, generating the concrete cracking, lowering the elasticity, reducing tensile strength, and thus leading to the deterioration of the concrete structure. Recent studies present an innovative method for inhibiting chloride corrosion by the addition of fibres into concrete to improve its toughness and tensile properties. By the addition of high fineness rice husk ash (RHA), the RHA would function as chloride adsorbent, preventing the chloride penetration through the concrete into the steel foundation. However, the addition of the RHA also affects the compressive strength, the workability, the consistency, and the slump of the concrete structure, limiting the mixed amount of the RHA that could be added in the concrete. A linear optimization model of the anti-corrosive RHA enhanced concrete has been formulated with the objective to minimize the effect of the chloride corrosion of the steel; whereas, the amount of the mixed RHA is limited by the critical concrete strength in term of modulus elasticity. In this study, the mass transfer coefficient, adsorption coefficient, and the Langmuir equilibrium isotherm are taken from the literatures. The chloride concentration is assumed to be 3.5 % w/v of the total chloride ion in salt water. The model has been validated with the measured data collected from open literatures. The optimum ratio between the RHA and cement mixture is discovered to be based on the void fraction of the concrete mixture. The optimum ratio is found to be around 10 % at the void fraction 0.8 and increasing to 25 % at the void fraction 1.2.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Study of atrazine removal by an adsorbent synthesised by water hyacinth
    (2018-08-14)
    Nuntamongkol, Sitanan
    ;
    Deetae, Pawinee
    ;
    In this work, water hyacinth was selected as a raw materials for synthesising the activated carbon used for removing atrazine, one of the most famous herbicides used in Thailand, from water. Three different treating methods were performed in order to attain the best adsorbent; untreated (AC), HCl-treated (HCl-AC) and NaOH-treated (NaOH-AC) activated carbons. After pyrolysis, NaOH-AC became ash, so it was not suitable for using as an adsorbent. Among these, HCl-AC was the best adsorbent for removing atrazine from water because of its highest surface areas. The adsorption experiments using AC and HCl-AC as the adsorbents confirmed that the adsorption efficiency of HCl-AC was higher than that of AC. In addition, the adsorption isotherm of HCl-AC was investigated by varying the atrazine initial concentration in the range of 3-15 ppm. The results best fitted with Langmuir isotherm that means this adsorption phenomenon was chemisorption with the maximum adsorbent capacity of 24.510 mg/g, Langmuir isotherm constant of 10.462 L/mg and the separation factor of 0.006 indicating that the equilibrium sorption of atrazine by HCl-AC was favourable.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Development of the near infrared spectroscopy model for detecting herbicide concentrations contaminated in water
    This research aims to develop the near infrared spectroscopy (NIR) models for detecting herbicide concentrations contaminated in water. Atrazine, the organochlorine herbicide, solution in the concentration range of 0-15 ppm were prepared in distilled water. Near infrared spectra were scanned by using Fourier transform spectrometer at wavenumbers of 12,500-4,000 cm<sup>-1</sup> (800-2, 500 nm). Partial least square regression technique was used to establish the NIR models for detecting herbicide concentrations. The developed models showed high prediction potential of herbicide concentrations contaminated in water with the R<sup>2</sup> of 0.97, RMSEE of 0.899 ppm, bias of -0.0003 ppm and RPD of 5.43. This indicated that these models can apply to analyse contamination of atrazine in the natural water sources.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Experimental and Modelling Analysis of Liquid-Liquid Formation in Alcohol-mixed Gasoline Fuel
    (2019-01-01) ;
    Rukquan, Muntira
    ;
    To tackle the environmental and sustainability problems, substituting gasoline, partially or solitary with bio-based alcohols becomes global practice. Bioethanol and biomethanol are being blended with gasoline in the ratio between 5-100 % by volume varying on the region. Various studies show positive impact of utilizing the blended fuel environmentally, while the others report the adequate efficiency of the blended fuel compare to the conventional gasoline; however, there were nearly no report on the failure or the shorten lifespan of the engine parts such as a high pressure pump (HPP) or an injector. It has been reported that water residue in the blended-bioethanol and biomethanol could cause the formation of the second liquid phase, leading to the chemical ageing reaction, which resulted in the corrosion of the HPP. To understand and prevent the damage, a quaternary behaviour of the blended gasoline-ethanol-methanol-water at the HPP operating condition is needed. In this work, an experimental study of the quaternary behaviour of the blended fuels has been conducted, the experimental data have been matching with the simulated results for better predictive of the mixture behaviour at different conditions. These results could potentially lead to limit or eliminate the HPP-corrosive problem.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Study of atrazine adsorption kinetics by using an activated carbon synthesised from water hyacinth
    (2019-09-24)
    Deetae, Pawinee
    ;
    In this work, atrazine, one of the most widely used herbicides in Thailand, was removed from water by activated carbon synthesized from water hyacinth. Before adsorption, 3 types of activated carbons used as adsorbents were prepared by different chemical treatment methods; untreated activated carbon (AC), HCl-treated activated carbon (HCl-AC) and NaOH-treated activated carbon (NaOH-AC). After pyrolysis, NaOH-AC became ash, so it was not suitable for using as an adsorbent. Brunauer-Emmett-Teller (BET) and CHNS methods were used to characterised 2 other adsorbents and the results showed that HCl treatment could improve the surface area and carbon content. This led to the better performance of HCl-AC for removing atrazine from water comparing to AC confirming by the adsorption experiments. In addition, the adsorption kinetics of HCl-AC, the best adsorbent in this research, was investigated by fitting with 4 kinetics models. The results showed that pseudo-second-order was the best kinetics model describing that the atrazine adsorption of HCl-AC was limited by adsorption and 2 active sites of adsorbent were required for adsorbing 1 molecule of atrazine.