cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2015.230
title: CHARACTERISTICS AND CATALYTIC PROPERTIES OF Pt CATALYSTS SUPPORTED ON Zn AND La-MODIFIED TiO2 IN SELECTIVE HYDROGENATION OF 3-NITROSTYRENE

description: The effect of Zn and La modified TiO2 on the catalytic performances of Pt/TiO2 was studied in the liquid-phase selective hydrogenation of 3-nitrostyrene (NS). Titanium dioxide (TiO2) was prepared by the solvothermal method at 320 °C with and without Zn and La modification and used as a support for preparation of TiO2 supported Pt catalysts. The catalysts were reduced at low (200 °C) and high (500°C) reduction temperatures before the reaction tests. The hydrogenation of NS was carried out batchwise at H2 pressure 2 MPa and 40 °C. The catalysts were characterized by N2-physisorption, X-ray diffraction (XRD), H2-temperature program reduction (H2-TPR), CO chemisorption, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and FT-IR analysis of adsorbed CO (CO-IR). The use of Zn-modified TiO2 provided higher NS conversion (64%) compared to the unmodified one (44%) at high reduction temperature. According to the N2-physisorption and CO chemisorption results, the Pt/Zn-modified TiO2 had greater BET surface areas compared to the Pt/TiO2 and higher amount of Pt active sites (higher Pt dispersion). The Zn-modified TiO2 supported Pt catalysts also exhibited high VA selectivity. In contrast, the Pt/La-modified TiO2 provided the lower vinylaniline yield compared to the unmodified catalysts because of lower amount of active sites as determined by the CO-chemisorption results.
DOI: 10.14457/cu.the.2015.231
title: PRODUCTION OF DIETHYLETHER BY CATALYTIC DEHYDRATION OF ETHANOL OVER HYDROXYAPATITE/ALUMINA-SILICA CATALYSTS

description: Hydroxyapatite and alumina-silica catalysts prepared by physical and chemical methods were examined in ethanol dehydration reaction for catalytic activity and selectivity. The catalysts prepared by physical mixing method were obtained by varying weight ratios of hydroxyapatite to alumina-silica (0-100 wt%). In chemical mixing method part, the hydroxyapatite and alumina-silica catalysts were prepared by sol-gel and co-precipitation methods. All catalysts were characterized by X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR) Analysis, Raman spectroscopy, NH3-tempearture programmed desorption (NH3-TPD) and thermal gravimetric analysis (TGA). The catalytic activity was determined in dehydration reaction of ethanol in order to produce diethylether (DEE). The reaction was run in gas phase at atmospheric pressure and temperature range from 200 to 400oC. For DEE production and catalytic performance, time-on-stream was performed at suitable condition during 10 hours. From the result, it was found that the optimal ratio of hydroxyapatite to alumina-silica catalyst was 4 to 6 by weight % for the physical mixing. The catalyst exhibited the highest DEE yield as 32% at 350oC. The catalyst prepared by co-precipitation method presented the highest DEE yield at 300oC as 24%.
DOI: 10.14457/cu.the.2015.232
title: AN UPGRADING OF LOW QUALITY SILICA SAND FROM THUNG TAGO DEPOSIT IN THAILAND

description: The research presents an upgrading of low quality silica sand from Thung Tako Deposit in Thailand. This research mainly focuses on the mineral processing of silica sand with the following objectives; (1) to reduce the iron impurities from silica sand by physical and chemical methods, (2) to analyze the iron content with spectrophotometer, to identify the heavy minerals by frantz isodynamic magnetic sepatator and to characterize the silica sand with X-Ray diffraction. The laboratory shaking table has been used for upgrading this type of the low grade silica sand deposits and 92.3 % SiO2 and 0.08% Fe2O3 were achieved under 100 inclination of the table as the best result. The non-magnetic final concentrate (silica sand) obtained by wet high-intensity magnetic separator was 98.6% which can respond the standard of the glass- grade silica sand and Fe2O3 0.08% was achieved with an environmental friendly manner. Flotation method can be reduced the iron impurities from 0.13% (raw) to 0.07% and 0.05% Fe2O3. Silica sand grade exceed up to 99% and the grade 0.05% of Fe2O3 were achieved by using 100 ml collectors (AOA and Nanza). The best conditions of the iron-impurities from the silica sand by using the strong industrial acid (H2SO4, HCl and HF) was 0.03 and 0.04% (from 0.13% Fe2O3 (raw)). As leaching time (0.5, 1, 2, 3, 4, 5 hours) increased, the iron constituent level decreased. The lowest values of the iron contents are obtained after 5 hour’s leaching time. Leaching of the silica sand sample seemed to be the most effective for the glass industry. This method is very expensive and the ensuing effluents are environmentally unacceptable. Even though all the techniques exhibited a successful removing the unwanted minerals, the financial and environmental aspects were considered. Therefore, Wet High Intensity Magnetic Separator technique is highly recommended.
DOI: 10.14457/cu.the.2015.233
title: FINITE ELEMENT SIMULATIONS OF SHRINKAGE CRACKS IN SLAB-ON-GRADE DUE TO RESTRAINTS

description: Due to many advantages of slab-on-grade; especially economy and durability, they are mainly used in industries, garages and pavements for sturdy floor and in residential buildings as well. However, it is such a sensitive one in the formation of cracks mainly due to the restraint to deformation. There are possible restraints which do not allow the concrete for freely volume change; friction between slab and sub-base, the effect of piles and columns, and casting sequence. This thesis aims to collect the data and observe the formation of cracks in slab-on-grade of two factories, mainly due to shrinkage deformation and then verify in the finite element program called ANSYS. The data from two industries, crack width and location, was collected as reference to implement cracking model in the finite element simulation. When simulated in program, the model was adopted from the cracked floor area cut by the contraction joints and the restrained boundary conditions as the floor area is very large. The output strain from the program was compared with the crack formation of reference project. The parametric study was focused on cracking which is due to the influence of casting sequence, the effect of friction between slab and subgrade, and the impact of different lengths ratio of the slab.
DOI: 10.14457/cu.the.2015.234
title: ANALYTICAL SOLUTIONS OF GENERALIZED T-STRESS IN LINEAR PIEZOELECTRIC MEDIA UNDER VARIOUS CRACK-FACE CONDITIONS

description: This thesis presents the closed-form solution of the generalized T-stress components of a penny-shaped crack in a transversely isotropic, linear piezoelectric, infinite medium under different crack-face conditions including electrically permeable, impermeable, semi-permeable and energetically consistent conditions. The solution for the case of uniform remote and crack-face mechanical/electrical loadings are derived for all four crack-face conditions whereas that for a crack under a pair of self-equilibrated, crack-face concentrated loads is obtained for permeable and impermeable cases. In the derivation, existing analytical solutions of the generalized stress field are employed together with an explicit expression resulting from the asymptotic expansion of the near-front field. All involved differentiations and limits are carried out in a careful manner following standard procedures and the final solution of the generalized T-stress components involves only elementary functions. In addition, the established Green’s function for the generalized T-stress is utilized to form an integral formula capable of computing the generalized T-stress for impermeable and permeable cracks under general crack-face loading. The analytical/semi-analytical feature of the derived solutions play a key role in the investigation of the influence of various parameters such as the crack-face conditions, electrical/mechanical far field, and the crack-face loading on the value of the generalized T-stress components along the crack front. A selected set of results is reported and significant and useful findings are concluded.
DOI: 10.14457/cu.the.2015.235
title: MECHANICAL PROPERTIES AND APPLICATION OF ARAMID FIBER REINFORCED CONCRETE

description: Corrosion of reinforcement is one of the main cause of deterioration of reinforced concrete (RC) structures which affects the load carrying capacity and durability of structures. Aramid fibers are known as synthetic fibers that have excellent tensile strength and high corrosion resistance. The purposes of this study are to investigate the effect of the presence of fibers and fiber geometry on mechanical properties of aramid fiber reinforced concrete (ARFC) and to investigate the flexural behaviour of corroded RC beams which were repaired by aramid fiber reinforced mortar and mortar product in the market. To accomplish the first objective, compressive, splitting, and direct tensile tests were conducted. Plain concrete and five fiber types of aramid fiber reinforced concrete having the different shape and length were tested. Fiber lengths were 30, 40 and 50 mm. Fibers were single and twisted shape. The volume fraction of fibers was 1.0% in all AFRC mixes. Significant improvement of splitting tensile strength was observed with the presence of aramid fibers. Especially for direct tensile strength, aramid fibers could provide better post-cracking tensile resistance. The length and shape of aramid fibers strongly affect the tensile behaviour of AFRC. Forty millimeter is the proper fiber length to increase the tensile strength. Although the single shape fibers yields the highest peak tensile stress, twisted fibers can resist higher load in post-peak region. In the second part, four reinforced concrete beams were tested under four point bending. One beams was control beam without corrosion and three beams were corroded by accelerate corrosion to reach 10% mass loss of longitudinal reinforcement. Two corroded beams were repaired at the tensile zone by aramid fiber reinforced mortar (AFRM) and mortar product in the market. The aramid fibers used are 40-mm-twisted fibers. The results showed that the load capacity of the corroded RC beam repairing by AFRM was recovered to be close to the non-corroded RC beam. The width of cracks in corroded beam repairing by AFRM decreases significantly. However, the flexural capacity of corroded RC beams could not be recovered when it was repaired by mortar only. Finally, a model was suggested to predict the flexural capacity of beams. The predicted results from the model are found to agree well with test data obtained. It shows that the flexural capacity of beams can be suggested by the predict model accurately.
DOI: 10.14457/cu.the.2015.236
title: Evaluation of combined water and gas dumpflood into oil reservoir

description: Secondary recoveries such as water and gas flooding are commonly used in order to improve oil production. However, water and gas injection typically incurs high capital and operating costs. In multi-stacked reservoirs in which water aquifer is located above an oil reservoir with a gas reservoir underneath, water from the overlying aquifer and gas from the underlying gas reservoir can be dumped into the oil reservoir instead of injecting them from surface. In order to investigate the performance of combined water and gas dumpflood in comparison to stand-alone water dumpflood and stand-alone gas dumpflood, a hypothetical reservoir model with simple geometry having a moderate dip angle is constructed using a numerical reservoir simulator. Water dumping well is located in the downdip part of the reservoir system while the gas dumping well is located updip. The oil producer is located between the two wells. The sizes of gas reservoir and aquifer are varied in order to determine their effect on oil recovery. Simulation results show combination dumpflood is more favorable than other methods when there is a presence of large aquifer size and small gas reservoir. In cases of large gas reservoir, stand-alone gas dumpflood is better a method. In all the cases, stand-alone water dumpflood is worse than stand-alone gas dumpflood and combination dumpflood. To optimize oil production in case of combination dumpflood, the oil producer should be located a little bit towards the water dumping well in order to avoid early gas breakthrough. The results from simulation also indicate that simultaneous dumpflood of water and gas at the beginning of the production is the best choice for combination dumpflooding schedule due to its ability to maintain higher oil reservoir pressure at higher oil production rate.
DOI: 10.14457/cu.the.2015.237
title: Assessment of Surfactant Flooding with Variations of Slug Injection Strategies in Waterflooded Reservoir

description: Introduction of surfactant into waterflooded reservoir may cause the reduction in surfactant efficiency by means of surfactant dilution and adsorption. However, it is possible to overcome this issue by utilizing concept of equilibrium shifting between different surfactant concentrations. Therefore, this study aims to evaluate the effects of surfactant flooding with multi-slug grading in waterflooded reservoir on additional oil recovery. Flooding operating conditions are initially evaluated to identify effects of injected surfactant concentration, surfactant injection rate, and time to implement surfactant flooding after water pre-injection for single-slug injection and multi-slug injection. The effects on oil recovery of reservoir parameters related to interaction between surfactant and rock surface including changes of properties related to relative permeability curves, such as irreducible water saturation and endpoint relative permeability, are then evaluated. Performance of surfactant flooding strategy is evaluated based on oil recovery factor. Simulated results indicate that two-slug surfactant injection yields better oil recovery than single-slug surfactant injection due to benefit of sacrificial adsorption or desorption process. Selection of type of two-slug injection strategy would depend on surfactant concentration of single-slug which is chosen to be modified; whereas, the selection of magnitude of concentration contrast between the two slugs would depend on placement of surfactant mass ratio. Modification of two-slug into three-slug injection does not show improvement in oil recovery in this study. However, additional oil recovery is observed to be better than single-slug surfactant injection. Assessment of operating parameters implies impacts on oil recovery performance. Surfactant concentration slightly shows effects on rate of change in oil recovery, but not on final oil recovery. The final oil recovery as well as the rate of recovering is more sensitive to the change in surfactant injection rate. Increase in injection rate results in faster and higher oil recovery. Time to implement surfactant injection does not show much impact on final oil recovery. Implementing at higher watercut would just delay production as a whole. For the effects of reservoir properties, changes in endpoint relative permeability to oil is more sensitive to the performance of surfactant flooding when compared to changes in endpoint water saturation.
DOI: 10.14457/cu.the.2015.238
title: THE CHARACTERISTICS AND CATALYTIC PROPERTIES OF TiO2 SUPPORTED Au-Pd CATALYSTS PREPARED BY FLAME SPRAY PYROLYSIS IN SELECTIVE HYDROGENATION REACTIONS

description: The preparation of bimetallic AuPd/TiO2 catalysts by one-step flame spray pyrolysis (FSP) resulted in narrow particle size distribution of small AuPd alloy particles (đp ~5 nm) on the TiO2 support. The conventional methods such as impregnation and deposition-precipitation methods, on the other hand, resulted in wider particle size distribution with some pore blockages and formation of new pore structure of the TiO2. The FSP-made AuPd/TiO2 showed good catalytic performances in the selective hydrogenation of 1-heptyne. More homogeneous composition of the individual AuPd nanoparticles was obtained upon reduction at 500 °C without significant changes of particle size and bulk composition. Nevertheless, the surface atomic Pd/Ti ratio decreased due to the TiOx migration onto the metals (so-called the strong metal-support interaction effect), resulting in lower activity. Reduction at high temperature was found to be unnecessary for the FSP-made AuPd/TiO2 catalysts in the selective hydrogenation of 1-heptyne. The highest yield of 1-heptene was 93% over FSP-AuPd/TiO2 R40 catalyst after 20 min reaction time. The characteristics of FSP-made catalysts were modified by changing the stoichiometric of precursor flow rate (PF) and dispersion O2 gas flow rate (DO). The activity of Pd/TiO2 catalyst prepared at 7PF3DO was improved so that it gave full acetylene elimination at 60 °C similar to the AuPd/TiO2 catalyst. Furthermore, the 2-nozzle FSP was employed for the preparation of AuPd/TiO2 catalysts with various particle configurations by controlling the mixing of the individual components from different flames. The catalyst performances for the selective hydrogenation of acetylene at 40 °C of the AuPd/TiO2 catalysts could be enhanced by separation of the TiO2 precursor from the mixed precursor of Pd and Au metals (TiO2 + AuPd).
DOI: 10.14457/cu.the.2015.239
title: Comparative Investigation and Improvement of Film Radiography Speed for Non-Destructive Inspection of Industrial Specimens

description: Film radiography is still used extensively in industry even though the image recording efficiency of the film is lower than &lt;1% and is much lower at high energy range. The imaging plate is &gt;10 times more sensitive than the conventional screen-film technique but its image reader and the imaging plate are relatively costly. Fading of the image data on the IP is also a problem. This research first emphasizes on improvement of the screen/film speed to reduce the exposure time by using the new PI-200 gadolinium oxysulfide (GOS) fluorescent screen. By using the PI-200 screens, the intensifying factors were found to be approximately 33.6, 39.0 and 61.3 for 100, 130 and 160 kVp x-rays while the IF’s of the conventional lead screens were approximately 2.8, 3.4 and 4.0 respectively. The intensifying factors (IF) for 192Ir and 60Co gamma-rays were found to be approximately 13.7 and 7.3 respectively while the IF’s of the conventional lead screens were approximately 5.8 and 1.4 respectively. The PI-200 screen thus could increase the speed of the conventional lead screen-film by at least 2 times depending on photon energy. Moreover, the sensitivity of the radiographs obtained from the PI-200 was comparable to those obtained from the conventional lead screen film technique. It was also found that the image quality could significantly improve by using lead filter to absorb the scattered gamma-rays at low energy range particularly when the specimens contained light elements such as concrete. In addition, objective of this research was to develop a device to determine the exposure time without need of information on the test specimen such as kind of material and thickness, source activity and source-to-film distance. The device was based on measurement of the transmitted x-ray or gamma-ray intensity by using a small PIN photodiode detector. The detector was mounted with a pulse processing unit and a microcontroller board and connected to a Bluetooth module. The counting data could simultaneously send to a smartphone to display the intensity. Application software was developed to control the measurement as well as to display the counting data. Prior to film exposure, the device was placed behind the specimen at required position to measure transmitted intensity which was inversely proportional to the exposure. Unlike in using the conventional exposure curve, correction factors for source decay, source-to-film distance, specimen thickness and kind of material were not needed. The developed technique and device was finally tested in radiography of the three specimens having different thicknesses to obtain a film density of 2.0 on the required areas. The obtained film densities on the required areas were found to be 1.92, 1.98 and 2.05 which were very satisfactory. The developed technique and device could the make radiographic process economic, convenient and more reliable.
DOI: 10.14457/cu.the.2015.240
title: Development of Analytical Software for Assessing Physical Protection System.

description: Assessment of physical protection system effectiveness is the priority for ensuring the optimum protection from unlawful acts against a nuclear facility, such as unauthorized removal of nuclear materials and sabotage of the facility itself. Since an assessment based on real exercise scenarios is costly and time-consuming, the computer-based analytical tool can offer the solution for approaching the likelihood threat scenario. There are several currently available tools that can be used instantly such as EASI and SAPE, however for our research purpose it is more suitable to have the tool that can be customized and enhanced further. In this work, we have developed a computer–based analytical tool by utilizing the network methodological approach for modeling the adversary paths. The inputs are multi-elements in security used for evaluating the effectiveness of the system’s detection, delay, and response. The tool has capability to analyze for the most critical path and quantify the probability of effectiveness of the system as a performance measure.
DOI: 10.14457/cu.the.2015.241
title: DEVELOPMENT OF SECURITY SUPPORTING GUIDANCE FOR ROAD TRANSPORT LICENSING OF RADIOACTIVE MATERIALS IN THAILAND

description: Radioactive materials are in widespread use and they need to be transported from one place to another. Transportation in Thailand is mainly by road. However, the regulating authority has no clear information on security regulations. Thus, the development of the security manual to support the application for transport of radioactive materials by road in Thailand will be very useful to related agencies. Studies were done to assess the status of security measures of relevant authorities and identify corrective actions necessary to ensure compliance with international standards. Result from the study is the security plan for the road transport of radioactive materials in Thailand.