cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2016.114
title: Desalination by capacitive deionization in microchannel

description: Water is a crucial factor for all living organisms. Although majority of the earth is covered by water, only small fraction the earth’s water is fresh water. The lacking of freshwater is an issue that every countries would like to solve. Desalination is one of the solutions. Unlike distillation and reverse osmosis, which require a lot of energy, capacitive deionization relies on removal of ions from water by applied potential. Hence it has potential to be cost effective. In this study, the capacitive deionization is applied in a microchannel. The experiments were conducted using NaCl solution. The 500-µm, 750-µm, and 1000-µm microchannel were formed between a graphite sheet used as anode and another graphite sheet used as cathode. The condition of the applied voltage was varied in the range of 0 - 5.0 V. Moreover, the graphite sheet was modified by steam activation at 1100°C for 30 minutes to increase its adsorption capacity. Activated graphites, gold sputtering on graphites and stainless steels were tested as electrodes. It was found that the use of the microchannel could significantly enhance the desalination efficiency by reducing mass transfer resistance. The salt removal would not increase as expected when operated over 2.06 volts, concerning electrolysis reaction. This objective of the study was to investigate behavior of the electrosorption of sodium ions and chloride ions within microchannel and study effect of electrode porosity in terms of desalinated efficiency.
DOI: 10.14457/cu.the.2016.115
title: Hydrogen production from sorption enhanced steam reforming of biogas via nickel over modified CaO sorbent

description: This research composed of two parts: (i) CO2 sorption study and (ii) hydrogen production performance tests using multifunctional catalysts. In the CO2 sorption section, the first group of metals (Mg2+, Sr2+ and Al3+) was loaded on CaO and tested the CO2 sorption and desorption performance over 10 cycles. Mg-CaO-HW offered the best stability in terms of CO2 sorption/desorption. Whereas Al-CaO-HW and Sr-CaO-HW exhibited a decrease in CO2 sorption capacity corresponding to 6 and 12% reduction. The second group of metals loading on CaO were Zr4+, Ce4+ and La3+. The results indicated that Zr-CaO-HW and Ce-CaO-HW possessed stable CO2 capacities over the 10 cycles. On the other hand, La-CaO-HW showed a decrease in the CO2 sorption capacity of 16%. This was due to the low-temperature oxygen storage properties of Zr-CaO-HW and Ce-CaO-HW, which enhanced the mobility of oxygen. In the section of H2 production, three sequences of Ni2+ loading on modified CaO were investigated. The results showed that Ni-Al-CaO-HW is the best multifunctional catalyst. The stability of Ni-Al-CaO-HW shows that CH4 conversion is still higher than 90% during the pre-breakthrough period for 5 cycle operations. Furthermore, Ni2+ was loaded on the modified sorbents Zr-CaO-HW, Ce-CaO-HW and La-CaO-HW. The results showed that Ni-Zr-CaO-HW and Ni-Ce-CaO-HW produced H2 at stable purities but with decreasing CH4 conversions. This was attributed to the loss of nickel active sites at the surface of the multifunctional catalysts due to the formation of CaCO3.
DOI: 10.14457/cu.the.2016.116
title: Study on the effects of gas pressure on the liftoff of spherical particles under electric field

description: The gas insulated switchgears are widely used in high voltage substation due to their advantages, such as smaller space requirement, less frequent requirement for maintenance, high operational reliability and safety. The failures in gas insulated switchgears due to the contamination of conducting particles are critical. This thesis studied the experiments on the lifting electric field of spherical particles under different gas types and pressures between parallel electrodes. The electrode gap was 10 mm. The various materials and sizes of spherical particles were used. The particle radius was 0.4, 0.68 and 1.19 mm for aluminum, 0. 5 mm for steel, and 1 mm for stainless steel spheres. We carried out the experiments under pressures of 0.5, 0.75, 1, 2 and 3 bar for the air, and 1 and 3 bar for a mixture of air/SF6 and air/N2. The proportion of gas mixtures was 1:1. The experimental results indicated that the particle liftoff depended on the pressure and the particle size for all gas media. The lifting electric field increased significantly with increasing the pressures and particle sizes. In addition, the lifting electric field of particle liftoff in the gas mixtures was smaller than that in the air under same pressure for each particle size. The difference in lifting electric field from positive and negative voltage was clear under 3 bar pressure or the particle of 0.4 mm radius in the air. However, the case of the gas mixtures indicated that the difference in the lifting electric field was significantly reduced. The difference between the electrostatic force and the gravitational force increased approximately by a linear relationship with the product of particle surface area and gas pressure. The force difference of the gas mixtures was smaller than that of the air.
DOI: 10.14457/cu.the.2016.117
title: Preparation of silica coated with polyethylene by in situ polymerization with metallocene catalyst

description: Nowadays , natural rubber is used as a raw material to produce several products due to its high strength. However, it has limit to be used because of low mechanical property. So, it needs to be improved by adding some filler, which is silica. Nevertheless, silica needs altering to be more hydrophobic as the rubber matrix. Thus it could be used to improve the silica surface by in situ polymerization. In this study, the in situ polymerization of ethylene over metallocene catalyst with three types of silica obtained from rice husk, commercial and synthesized silica. The modified methylaluminoxanes (MMAO) is used as cocatalyst. There were three parts of this study. The first part was studied the characteristics of silica before and after immobilization with MMAO, prepared by ex situ immobilization method by by XRF, N2 physisorption, SEM-EDX , XRD, XPS, and TGA-DSC. The second part studied the catalytic activities of silica at different temperatures (60oC and 70oC) and immobilization method (ex situ and in situ). The in situ immobilization expressed higher catalytic activity than the ex situ method. The activity of polymerization via ex situ immobilization of SiO2-Com was the highest at 70oC and SiO2-Syn was the highest catalytic activity at 60oC. However, the morphologies of polymer with ex situ immobilization, which was spheroidal were better than in situ immobilization which was irregular shape. All obtained polymers were characterized in the third part by SEM-EDX , XRD, and TGA-DSC. It can be concluded that the SiO2-Com coated with polyethylene by in situ polymerization with metallocene catalyst at 70oC via ex situ immobilization expressed the highest catalytic activity. SiO2-RH coated with polyethylene by in situ polymerization with metallocene catalyst at 70oC via ex situ immobilization expressed the lowest catalytic activity.
DOI: 10.14457/cu.the.2016.118
title: Analysis of high capacity mobile network with 3D in-building dense small cell

description: This dissertation research emphasizes on achieving high capacity demand of next generation mobile networks (NGMN), i.e. fifth generation (5G), with small cells, i.e. femtocells, deployed in 3-dimensional (3D) indoor coverages by employing such procedures as managing co-channel interference, enforcing a minimum distance, reusing spectrum, and splitting control-plane and user-plane (C-/U-plane) of femtocells. In conventional mobile networks, a common feature is tightly coupled C-/U-plane architecture (CUCA) which is one of the major reasons for most of the problems that small cell network densification faces, e.g. complex interference management. This call for developing a new C-/U-plane split architecture (CUSA) by decoupling C-/U-plane. Further, in cellular mobile networks, most of the data traffic is generated within indoor coverages, mainly in urban environments where an existence of dense high rise multi-floor buildings is a typical scenario. Furthermore, mobile radio propagation in 3D scenario is far more complex than that of 2D scenario. These cause such inevitable issues as small cell network architecture modeling and interference characterization, resource reuse and allocation strategy development, and small cell densification limit characterization to call for their in-depth investigation and the development of new design technique for 3D in-building small cell networks. This dissertation research addresses these aforesaid issues. More specifically, the following objectives are addressed in this dissertation: (i) a review on enabling technologies for proposing a framework of NGMN architectural evolution to achieve the prospective capacity of NGMN; for cell-centric networks, (ii) an adaptive almost blank subframe (ABS) based enhanced intercell interference coordination (eICIC) enabled frequency reuse and scheduling algorithm (FRSA) for an orthogonal resource reuse and allocation (ORRA), (iii) a tractable analytical model for interference characterization and minimum distance enforcement for non-ORRA (NORRA), and (iv) a novel clustering approach along with developing a number of strategies to reuse resources in femtocells within a 3D multi-floor building; for device-centric networks, (v) a novel multi-band enabled small cell and UE architecture for uplink/downlink (UL/DL) and C-/U-plane splitting, (vi) numerous small cell base station (SCBS) architectures for performance comparisons between CUCA and CUSA, and (vii) a centralized 3D radio resource allocation and scheduling approach for CUSA.
DOI: 10.14457/cu.the.2016.119
title: REINFORCING NATURAL RUBBER WITH BACTERIAL CELLULOSE VIA LATEX SOLUTION PROCESS

description: Natural rubber (NR) is an important material for a variety of the elastomer industry such as tires, automotive interior parts, gloves as well as packaging due to the excellent elastic properties. However, there are some drawbacks such as low tensile strength and low abrasion resistance. Moreover, its applications are also limited because of its poor resistance to oil and solvents. Preparation of NR-composites reinforced with cellulose to enhance Young’s modulus and tensile strength of the NR which is a decreasing solution to these defects and limitations has attracted much interest in recent years. Usually, in the mixing step of rubber-cellulose composite preparation, there are problems of agglomeration and low dispersion of cellulose due to the difference of molecular polarity between cellulose and NR. In this study, in order to enhance the properties of NR-composite films, we focus on NR reinforced with bacterial cellulose (BC) which has many advantages including biocompatibility, remarkable mechanical properties, and high hydrophilicity via one-step latex solution processing. In addition, this study will also explore the modification of NR-BC composites with organic acid to enhance the composite structural stability. The NR-BC composites (NRBC) and the acid modified NR-BC composites (ANRBC) films were characterized for physical, chemical and biological properties. The NRBC composites were successfully prepared via latex solution process. BC fibers dispersed homogeneously within the NR matrix for every concentration with different BC fiber contents. The mechanical properties of the NR-composite films were improved with the BC loading while the structural stability of ANRBC composites was enhanced after the acid modification. However, this improved NR-BC interaction had no significant effect on the biodegradability in soil.
DOI: 10.14457/cu.the.2016.120
title: Extraction of Lutein Fatty Acid Esters from Marigold Flower using Liquefied Dimethyl Ether (DME) as extractant

description: This study will focus on the investigation of extraction of lutein fatty acid esters from marigold flowers using liquefied dimethyl ether (DME) which is nontoxic solvent as extractant. Since it is gaseous at normal temperature and pressure, DME can be easily removed from the final product by pressurizing. In this study, was divided into 3 parts. Part I involves the determination of suitable DME extraction. Effect of extraction conditions including solvent to sample ratio (w/w) and extraction temperature at 400 rpm for 30 min on extracted yield of lutein esters were investigated. The highest amount of lutein esters was found to be 20.65 mg/g dried marigold at the condition of 33:0.5 solvent to sample ratio and 35oC. The results were compared with solvent extractions using hexane as solvent and supercritical carbon dioxide extraction. Then, compared with DME extraction using wet sample with 80% and 70% moisture content. Part II deals with the determination of suitable saponification condition in order to convert the lutein esters to free lutein that was ratio of ethanol to oleoresin 20:1, 2.5% KOH concentration, 35 °C for 4 h. at such conditions, approximately 150 mg free lutein /g oleoresin was obtained. In part III, the evaluation of simultaneous DME extraction and saponification was carried out. The suitable condition for simultaneous DME extraction and saponification of lutein esters to free lutein was ratio of ethanol to dried marigold 10:0.5, 5% KOH concentration, 35 °C for 1 h. at such conditions, approximately 20.71 mg free lutein /g dried marigold was obtained. Then compared with those obtained with sequential DME extraction followed by saponification for free lutein that is 16.65 mg free lutein /g dried marigold. And also compared with simultaneous DME extraction and saponification using wet sample, at this study the amount of free lutein was 19.22 mg free lutein /g dried marigold.
DOI: 10.14457/cu.the.2016.121
title: OXIDATIVE DEHYDROGENATION OF ETHANOL OVER Cu-AgLi/Al2O3 CATALYSTS

description: In this research, the effect of copper and silver weight ratio (Cu:Ag of 100:0, 70;30, 50:50, 30:70, 0:100) supported on mixed-phase of Al2O3 catalysts was investigated. The mixture of equal phase between gamma- and chi-Al2O3 support was synthesized via the solvothermal method. The support was brought to loading with copper, silver (5 wt%), and lithium (0.7 wt%) that was prepared via incipient wetness impregnation technique. The catalytic activity was identified through the ethanol dehydrogenation and oxidative dehydrogenation reactions in packed-bed reactor at 200 to 400oC under atmospheric pressure. The performance in the reaction was found that Cu(0)Ag(100)Li/M-Al showed the highest acetaldehyde yield and ethanol conversion in all reaction temperatures of dehydrogenation reaction study because of its high specific surface area and the large amount of total basicity. Especially, the highest acetaldehyde yield of 81% existed at 350oC. This catalyst also displayed the excellent value of acetaldehyde yield in oxidative dehydrogenation that given the highest yield at 300oC of 92%. In addition, Cu(30)Ag(70)Li/M-Al showed the greatest yield at the lowest temperature of studied reaction temperature, 250oC with acetaldehyde yield of 59%. Along the stability test in time-on-stream for 10 hr, the comparison result between dehydrogenation and oxidative dehydrogenation revealed that the addition of oxygen can prevent the deactivation of catalysts via coke formation and metal sintering. Cu(0)Ag(100)Li/M-Al, which was reacted in oxidative dehydrogenation of ethanol at 300oC had the lowest coke deposition on catalyst surface compared to itself reacted in dehydrogenation at 350oC and Cu(30)Ag(70)Li/M-Al reacted in oxidative dehydrogenation at 250oC.
DOI: 10.14457/cu.the.2016.122
title: Improvement of feature preservation in high efficiency video coding

description: Feature information is known as interest points (keypoints) in an image which is very useful information for video analytic functions such as object detection and tracking, video classification, etc. Due to the characteristic of video coding, it is exploited following human vision system where high frequency component could be removed for better compression. Thus, it can affect to the keypoints, which mostly are the edge information. As a result, with less number of keypoints left, this affects the accuracy of video analytics. To solve this problem, this thesis presents an algorithm to preserve feature information of reconstructed video in the high efficiency video coding (HEVC). Scale-Invariant Feature Transform (SIFT) is chosen to extract the keypoints from raw video sequence. We then consider keypoints as an indicator of the importance of the largest coding unit (LCU). Adaptive LCU selection is defined to determine LCU into two different groups, important LCU group (IMLCU) and non-important LCU group (Non-IMLCU). Moreover, two different bit allocations are generated in rate control to each group based on coding mode, Intra or Inter mode, to achieve the target bit rate and also to keep the feature information. The experimental results show that our proposed algorithm can maintain more keypoints compared to HEVC reference software at the same bitrate based on the peak signal-to-noise ratio (PSNR) and SIFT similarity computation.
DOI: 10.14457/cu.the.2016.123
title: Economic dispatch management of electric power plants for profit maximization

description: The key strategy of power plant business in the deregulated electricity supply industry is to maintain profitability, especially for a private energy company that allows general public to take part in investment for business expansion. The right strategy move is to maximize profit from selling electricity and steam, at the same time fund intensive research and development programs to seek for new alternative energy in order to supplant limited fuels and lower cost of production. The corporate annual report revealed that the major source of revenue comes from the sales of electricity and steam; however, profit has continually declined over the past few years. Decreasing profit was partially due to external effects, such as monopolized pricing determination and volatile economic factors. The company is not allowed to proportionally adjust the prices of electricity and steam to changes in such effects. The executives identified that the main cause of decreases in profit is from independent production and operations management without economic dispatch applications among the power plants. Consequently, the company had to excessively stock up fuels and schedule unplanned maintenance, which resulted in lower productivity and incapability to deliver some outputs to the customer. A spreadsheet-based program was developed to help make a small-scaled managerial decision, how much electricity and steam should be generated and sold to each customer group during periods of peak hours and off-peak hours to achieve maximum profit without violating the sales contract agreements. Several quantitative determination processes for unit cost, prices and profits were constructed and later embedded in the spreadsheet program. The mathematical linear programming model for optimizing total profit during each of the periods was formulated. Two feasible scenarios for each of the periods were comparatively simulated to see the best alternative towards profit maximization. The simulation results show that the optimal scenario is applicable to both periods. Although some electricity demand could not be fully satisfied resulting in penalty, this scenario provided the total maximum profit and was able to satisfy the power systems and the legal constraints while not severely violating the sales contract agreements relative to another scenario. The results from sensitivity analysis of exchange rate, coal price, fuel oil price, coal-to-biomass fuel ratio and fuel transfer charge also show that all of these factors have strong effects on profitability, allowing to examine a series of possible changes that will not affect the optimal solution of economic dispatch management.
DOI: 10.14457/cu.the.2016.124
title: Effect of transition metals promoted on Vanadium phosphorus oxide (VPO) catalysts in the partial oxidation of n-pentane

description: Vanadium phosphorus oxide (VPO) catalysts have been employed in partial oxidation of n-butane and n-pentane. In this study, VPO catalysts were synthesized by refluxing vanadyl phosphate dihydrate (VOPO4•2H2O) with isobutanol and modified with transition metals promoters such as Co, Bi, Fe, and Mn at the mass ratio of M/V 0.35. In the first part, Mn was found to be the best metal to improve the performances of VPO catalyst in n-pentane oxidation. Then the Mn-VPO catalysts were prepared with different ratios of Mn/V loadings at 0.25, 0.35, 0.45, 0.55, and 0.65. All the catalysts were calcined at 300ᵒC for 8 h to generate the vanadyl pyrophosphate ((VO)2P2O7) phase which is the active phase of VPO catalysts and was confirmed by the XRD results. As shown by SEM results, all the synthesized catalysts showed the rosette-shape morphologies of vanadyl pyrophosphate. The transition metal promoted catalysts presented the formation of V4+ state which provided a better catalytic performance with 42.7-55.8% n-pentane conversion, 28.9-62.5% MA selectivity, and 8-13.1% PA selectivity. The optimum ratio of Mn/V was determined to be at 0.45
DOI: 10.14457/cu.the.2016.125
title: Developing a commercialization model for innovative products and processes in a petroleum firm

description: In Thailand, the petroleum industry is a major contributor to the economy as a supplier of crucial petroleum products. Due to its geographical location, multinational oil & gas companies have established their operations in Thailand. For Thai petroleum firms to remain competitive in the industry, innovation can be used as a strategy. Specifically, commercialization of inventions can bring firms competitive advantages in terms of financial returns, and business opportunities for partnerships. The objective of this research is to develop a commercialization model for inventions in Thailand’s petroleum industry. The model is aimed to serve as a roadmap of essential activities for individual work functions throughout the stages of the commercialization process. Additionally, the model will provide an overview of the relationships between work functions and their responsibilities. The methodology used in this research consists of three stages. The first stage is developing a preliminary commercialization model by integrating data from literature and data from interviews of industry experts in Thailand. The second stage is refinement of the model through evaluating the preliminary model on commercialization experts. Finally, the last stage uses a Thai petroleum firm as a case study to adapt the model for use at company-level. As a result, this research has developed 2 commercialization models, namely an industrial commercialization model, and a company commercialization model.
DOI: 10.14457/cu.the.2016.126
title: Interpretation of rapid pile load testing

description: Nowadays, the rapid pile load testing has been used frequently by geotechnical engineers in the world. Comparing to static load testing, the rapid method is quicker and more efficient. However suitable techniques shall be used for obtaining load-displacement curves from rapid load test results. Among methods in literatures, the Unloading Point method can be considered as the simplest and most common. It performs well in sandy soil, but over-predicts the capacity of piles in clayey soils. Therefore, a new technique which performs well in both of sandy and clayey grounds is proposed in this study. Moreover, the existing dynamic pile load test is modified to approximately meet the requirements of rapid test on driven piles. The modification and illustration of rapid tests on driven piles are carried out by GRLWEAP 2010.