cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2015.189
title: DESIGN AND EVALUATION OF DIMETHYL CARBONATE PRODUCTION FROM CARBON DIOXIDE

description: A systematic computer-aided framework for sustainable process design is presented. The framework integrated with various methods, tools, algorithms and databases is based on a combined process synthesis-design-intensification method. The synthesis-stage involves superstructure based optimization to identify promising networks. The design-stage involves selection and analysis of the identified networks as a base case design in terms of operational feasibility, economics, life cycle assessment factors and sustainability measures, which are employed to establish targets for improvement in the next-stage. The innovation-stage involves generation and screening of the more sustainable alternatives through a phenomena-based process intensification method. The proposed framework was applied to the CO2-based DMC production process. A superstructure of processing routes including CO2 direct synthesis and indirect syntheses via urea, ethylene carbonate and propylene carbonate, was generated and evaluated to determine the most promising processing route, which was then analyzed in detail to identify design improvement targets. Through a phenomena-based method, new more sustainable process alternatives matching the design improvement targets were identified. For the evaluation of alternatives, the measures include sustainability metrics, economic potential indicators as well as LCA factors. The urea route with reactive distillation was found to be the best alternative, offering superior performance to the conventional BAYER process.
DOI: 10.14457/cu.the.2015.190
title: OPTIMAL WELL DESIGN FOR WATER DUMPFLOOD

description: Water dumpflood is a proven technology that can help maintain reservoir pressure and improve oil production. This process helps save capital and operating costs of pump and injection pipeline. However, due to limited control of the amount of water being dumped, oil recovery from water dumpflood may not be very high. Thus, there is a need to design appropriate water dumpers and oil producers in order to displace oil as much as possible in such situation. In this study, a numerical reservoir simulator was used to compare the performance of different well types (vertical versus horizontal dumpers and producers), well lengths (in the case of horizontal penetration in the oil zone), and starting time for dumpflood for different aquifer sizes. The reservoir simulation model is based on reservoir and fluid properties of an onshore oilfield in Thailand. For well type, results from simulation indicate that vertical dumper and horizontal producer can yield oil recovery of 30.78% while oil recovery of vertical dumper and vertical producer is 14.46%. Simulation results also indicate that longer horizontal well length yields higher oil recovery and less water production. For starting time of water dumpflood, it does not have a significant effect on oil production. In summary, water dumpflood has better production performance than natural depletion and worse performance than conventional waterflood.
DOI: 10.14457/cu.the.2015.191
title: HYDROGEN PRODUCTION VIA SORPTION-ENHANCED STEAM METHANE REFORMING USING HYBRID CATALYTIC ADSORBENT

description: Synthesis of hybrid catalytic CaO-based alumina sorbent has been investigated to use for H2 production via sorption enhanced steam methane reforming. Calcium D-gluconic acid, (C12H22CaO14) and Calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) were selected to study the effect of calcium precursor on CaO properties. Calcium-based sorbent derived from calcium d-gluconic acid (CG-AN) shows higher CO2 sorption capacity (0.387g CO2/g sorbent) than calcium-based sorbent derived from calcium nitrate (0.172g CO2/g sorbent) at 600˚C and atmospheric pressure under 15%v/v CO2. Adding surfactant was further applied to improve capacity of sorbent. The results show 3 mM of Hexadecyltrimethylammonium bromide (CTAB) can improve CO2 sorption capacity of CG-AN as CO2 sorption capacity can be improved to 0.45 g CO2/g sorbent whereas addition of surfactant cannot improve CO2 sorption capacity for CN-AN. In addition, stability of both sorbents were tested for 10 cycles and the results show that CG-AN-CTAB 3 mM provides higher CO2 sorption capacity than CN-AN-CTAB 3mM at all cycles; sorption capacity of CG-AN-CTAB 3 mM is reduced 36.8% from the 1st cycle to the 10th cycle and that of CN-AN-CTAB 3 mM is reduced 30.9% from the 1st cycle to the 10th cycle. When modified calcium-based sorbent was used in SESMR process at 600˚C, S/C=3 and atmospheric pressure, 12.5%Ni-CG-AN-CTAB 3mM prepared by wet mixing shows 91.2% H2 purity for 45 minutes and 83%CH4 conversion, which was higher than those of 12.5%Ni-CG-AN without CTAB of 88.7% H2 purity for 45 minutes and 79.4% CH4. In addition, it was observed from our studies that method to synthesize hybrid catalytic sorbent has an effect on H2 production. By preparing 12.5%Ni-CG-AN using sol-mixing can improved CH4 conversion to 82.3% and H2 purity to 94% for 30 minutes.
DOI: 10.14457/cu.the.2015.192
title: EFFECT OF SULFENAMIDE ACCELERATORS, CHEMICAL BLOWING AGENT AND GRAPHENE ON FORMATION AND PROPERTIES OF NATURAL RUBBER FOAM

description: Natural rubber foam (NRF) was produced by chemical blowing technique with compression molding process. This process still has a problem with oversized dimension after removing specimen from the mold. The effect of azodicarbonamide which is the chemical blowing agent, sulfenamide accelerators and surface treated graphene with cyclohexyl diamine via diazonium reaction were investigated to solve this problem and improve properties of NRF specimen. Although the presence of azodicarbonamide can accelerate sulfur vulcanization due to amine derivatives from thermal decomposition of chemical blowing agent, NRF with high content of azodicarbonamide reduces the m order of autocatalytic reaction which means low crosslink of rubber molecules. Moreover, NRF at 4 phr of azodicarbonamide shows the smallest bubble diameter with good properties. The different chemical structures of sulfenamide accelerators are also studied. NRF with N-cyclohexyl benzothiazole-2-sulfenamide (CBS) system reveals the fastest sulfur vulcanization rate resulting in the smallest bubble diameter with narrow size distribution and lowest thermal expansion coefficient. This system also has the lowest activation energy (Ea) among other rubber foams with sulfenamide accelerators owing to high basicity from high stability of amine species after this accelerator forms as a complex species with other ingredients in sulfur vulcanization system. The last factor that should be concerned is the presence of graphene and surface treated graphene with cyclohexyl diamine via diazonium reaction. The higher graphene content in rubber matix, the faster sulfur vulcanization rate is obtained as a result of the remaining oxygen functional group on surface of graphene. Furthermore, surface treatment of graphene improved dispersion in rubber matrix. It also shows the slowest sulfur vulcanization rate due to the reaction between cyclohexyl diamine and oxygen functional groups on the graphene surface. NRF with 3 phr of treated graphene has the highest tensile strength at break due to good dispersion of graphene particle and low cell density in natural rubber foam product.
DOI: 10.14457/cu.the.2015.193
title: NOISE SUPPRESSION IN 40 GIGABIT-PER-SECOND COHERENT TIME-SPREADING OCDMA SIGNAL TRANSMISSION OVER PASSIVE OPTICAL NETWORK

description: In this dissertation, we studied the OCDMA system over PON at the bit rate per channel of 40 Gbps using Fourier code in order to suppress the noise. We proposed the spreading-time to bit period ratio (SBR) as a factor that can suppress the noise. Our results showed that the highest chip number was resulting in the lowest noise and the BER due to its highest PCR. We further investigated the performance of the system with the different SBR. We performed the mathematical calculation to obtain the noise variance and the BER. The results showed that, in the worst case, and the average case, the BER of the system employing SBR = 0.6, 0.4, and 0.2 was greater than the conventional system using SBR = 1.0, and 0.8. The simulation results confirmed the validity of our mathematical values. Moreover, the comparison between the TDMA and the OCDMA-PON was demonstrated. We showed that the OCDMA-PON was superior in terms of bit rate per subscriber, power budget, and the system complexity at the same bit rate, respectively. Finally, the system verification was proved by performing the experiment. We used the AWG and the PLC en/decoder with the SBR = 0.1 and 0.8. The results had reached and agreement with our mathematical calculation and the simulation, respectively.
DOI: 10.14457/cu.the.2015.194
title: PRELIMINARY EVALUATION OF DOSES FOLLOWING HYPOTHETICAL EXPLOSIONS OF RADIOLOGICAL DISPERSION DEVICES

description: The objective of this research was to perform preliminary evaluation of doses following hypothetical explosions of radiological dispersion devices (RDDs) at the studied areas (Victory Monument, Siam Square and Pattaya city). Calculations were based on the plume dispersion computer code, Hotspot Health Physics Codes program, which implemented the Gaussian plume dispersion model and provide contour lines corresponding to specified radiation dose levels (1,000, 250 and 5 mSv TEDE). Parameters used in this study were radionuclide species (Co-60, Cs-137 and Ir-192), material at risk (100 Ci), high explosive (10 and 25 pounds), meteorological data (wind direction and wind speed period for the past 20 years) and population data. ArcGIS Desktop 9.3 was used to analyze further, Maximum distances of the plume dispersions and total number of populations and sub-district names of affected areas from explosions of RDDs. The benefit of this analysis is the subsequent emergency response plans that can be prepared and offered in order to mitigate and control the hypothetical situations. Areas receiving the total effective dose equivalent (TEDE) of more than 250 mSv should be considered immediate evacuation areas.
DOI: 10.14457/cu.the.2015.195
title: Behavior of port structures under tsunami loading

description: LPG and LNG terminals consist of loading platform, dolphins, jetties and trestles. Since these structures are required to berth large vessels for loading and unloading of the cargo they are located in near shore area. Due to that often terminals or parts of it are constructed with limited or no protection against tsunamis. After the 2004 Indian Ocean tsunami, severe damage to marine structures has been observed in many affected areas. In order to better understand responses of port structures during tsunami, an analysis of the berthing dolphin, mooring dolphin and loading platform is conducted. Behavior of port structures under hydrodynamic drag forces and buoyant forces is analyzed using linear elastic models. Tsunami amplitude and current velocity are chosen based on previous simulations and observed data. Tsunami amplitude between 1-3m and tsunami velocity between 1-3 m/s are considered in the analysis. Top deck displacement and internal forces in piles are compared and discussed. Effects of the structural and tsunami parameters on structure behavior are reported. An effect of utilization of batter piles with rake from 1:32 to 1:3 is studied. It is observed that using batter piles reduces displacement and bending moment values, however increases axial forces. For the mooring dolphin with piles raked 1:4, reduction of displacement is equal to 82% and reduction of bending moment is equal to 60% of the values of structure supported only by vertical piles.
DOI: 10.14457/cu.the.2015.196
title: DEHYDRATION OF ETHANOL OVER Mn – MODIFIED ALUMINA CATALYST

description: Ethylene is widely used for raw material in industries. Currently, the method to produce the ethylene is steam thermal cracking of hydrocarbons. The weak point of this method is that the reaction temperature is about 600-1000 ๐C that is very high and hydrocarbons as raw materials are limited quantities such as naphtha. The purpose of this research is to investigate an alternative way of ethylene production. The ethanol dehydration is a novel promising way of ethylene production. The ethylene from this process is environmental friendly because using ethanol as raw material can reduce the utilization of fossil fuel. The catalyst for this reaction is alumina prepared by the solvothermal method and characteristics of catalyst were determined by XRD, SEM, BET and NH3-TPD. In this research, we compare performance of γ- χ alumina and manganese modified alumina catalyst in ethanol dehydration reaction at various temperatures between 200–400๐C. The γ- χ alumina catalyst shows high ethanol conversion and high ethylene selectivity more than the manganese-modified alumina catalyst. At 400 ๐C, the highest ethanol conversion and highest ethylene selectivity were observed for all catalyst. In terms of ethanol conversion, it was in the order of Al2O3 (77.3%)&gt; 0.05Mn/Al2O3 (53.1%)&gt; 0.1Mn/Al2O3 (39.7%) and ethylene selectivity was in order of Al2O3 (96.8%)&gt; 0.05Mn/Al2O3 (86.7%)&gt; 0.1Mn/Al2O3 (70.5%). However, the Mn modification can result in increased diethyl ether (DEE) selectivity at low temperature. At 250 ๐C, the highest DEE selectivity, was found for 0.1Mn/Al2O3 (100%), while DEE selectivity 0.05Mn/Al2O3 (93.0%)&gt;Al2O3 (82.4%) was observed.
DOI: 10.14457/cu.the.2015.197
title: ON-TIME DELIVERY IMPROVEMENT FOR HEAT RECOVERY STEAM GENERATOR

description: Due to the high competitiveness of today's business, the organization has driven to change and develop continually in order to gain competitive advantage in business. Managing project effectively is essential to help the project succeed under existing constraints and achieve the project objectives. This could strengthen the strategic plan of the organization and lead organizations to success in business. This thesis aims to control and improve on-time delivery performance to reduce delays and unnecessary acceleration of the project for Heat Steam Recovery Steam Generator manufacturer. In this case project study, the control system of old project was analyzed and improved by dividing into three main processes which are planning, executing, and monitoring and controlling process. Based on historical data, it was found that the company has trouble with controlling project management by delays delivery and getting fine. For this reason, the principle of time management guidelines of the Project Management Body of Knowledge (PMBOK) was applied in those processes of case project study. Microsoft project program was used to develop project schedule in greater detail which enable team to comprehend the direction of the project. The schedule illustrates sequence, network relationship between activities, estimated time to complete, start and finish date, critical path and so on. During project execution, weekly progress shall be reported to project management team, S-Curve and Critical path are mainly tools for progress measurement. The results of the study shows that project management can improve the management of the case studies more efficiently. There was no delay in delivering the completed project.
DOI: 10.14457/cu.the.2015.198
title: Effects of dissolved organic matters and biofilm on disinfection by-products formation potential in tap water

description: This study aims to investigate the effects of biofilm in drinking water distribution system on dissolved organic matter (DOM) consumption and adsorption and to analyze the disinfection by-products formation potential (DBPsFP) which caused by DOM or biofilm and the combination of DOMs and biofilm in treated water distribution system. Also, the objective of this research is to evaluate the adsorption efficiency of occurred DBPs by using granular activated carbon (GAC). The results showed that active and inactivated biofilm has capacity to consume and adsorb mixed DOM, hydrophilic DOM (HPI) and hydrophobic DOM (HPO) fraction. Biological consumption of all kind of DOMs was confirmed by comparing DOM consumption data of active biofilm with abiotic data. For the result of formation potential based on organic carbon content, Haloacetonitriles (HANs), Haloacetic acids (HAAs), and Haloketones (HKs), except Chloroform (CF), have high formation potentials in individual samples of DOM and DOM fractions but started to decrease formation potential in mixed DOM or DOM fractions with biofilm. That might be caused by the consumption of DOM and occurred DBPs (excepted CF) by biofilm’s activities. HANs seem to have high formation potential which calculated based on the amount of dissolved organic nitrogen (DON). From obtained results, the existing of re-growth biofilm in distribution system might reduce DBPsFP of HANs, HAAs and HKs that occurred from the reaction of chlorine and remained DOM. Also, dichloroacetonitrile (DCAN) seems easier to be adsorbed by granular activated carbon (GAC) than CF.
DOI: 10.14457/cu.the.2015.199
title: BEHAVIOUR OF STEEL FIBER REINFORCED CONCRETE UNDER BLAST LOAD

description: Recent studies show that adding steel fiber into concrete will enhance tensile capacity especially in high strain-rate loading condition. This thesis shows the results from experiments and finite element analysis simulations for the responses of steel fiber reinforced concrete (SFRC) panels and normal reinforced concrete (NRC) panels subjected to blast loading. Two panels per fiber weight ratio of 0 (concrete without fiber), 30, and 60 kg per cubic meter were casted. Total of 6 panels were casted with controlled cementitious matrix strength within a range of 55-60MPa. The steel fiber used in this study is hook-type fiber with an aspect ratio of 80 which, from past study, found to have a good performance for impact loading. The concrete panels were subjected to blast load using TNT explosive weighing 1lb and 2 lb all at a fix stand-off distance of 0.5 meter. Deflection and acceleration responses were measured from the experiment. Simulation models were developed via finite element analysis program "ABAQUS". The experiment results showed that the SFRC panels possesses better resistance against blast loading than NRC panels.The analysis models were also proven to have good accuracy in predicting panels' responses.
DOI: 10.14457/cu.the.2015.200
title: EVALUATION OF STEAM ASSISSTED GRAVITY DRAINAGE PROCESS COMBINED WITH HYDRAULIC FRACTURING IN SHALY-SAND RESERVOIR

description: Thermal recovery is a technique usually implemented in reservoirs containing viscous oil. Nowadays, a technique called Steam Assisted Gravity Drainage (SAGD) is modified and implemented in most fields around the globe. Compared to waterflooding, SAGD improves both sweep and displacement efficiencies, leading to high oil recovery. However, SAGD requires good vertical connectivity that can be deteriorated by which the presence of shale acting as barrier to the flow path of fluids. In order to overcome this low connectivity between wells, hydraulic fracturing is generated to create vertical paths. In this study, two sandstone reservoir models are constructed to possess structural shale and laminated shale, respectively. Hydraulic fracturing is performed to evaluate the performance on these models by evaluating both controllable and uncontrollable parameters. The entire study employs STARS commercialized by Computer Modelling Group (CMG) as a tool. From reservoir simulation results, models combined with hydraulic fractures improve oil recovery by 3.6 and 15.2 % in structural and laminated shale base models respectively when the best steam injection rate is used. Steam-oil ratios are also reduced in both cases, indicating more favorable condition. Symmetrical distribution of hydraulic fractures optimizes volumetric sweep efficiency and high steam quality is desirable for this combined technique. In addition, steam trap is found to be an effective method to improve thermal efficiency. However, oil recovery factor is unavoidably reduced as amount of injected steam is limited. For reservoir parameters, high percent of shale volume requires better vertical communication through hydraulic fracturing due to their low heat conductivity. Benefit from hydraulic fracturing is lowered when laminated shale is discontinuous as channels for steam to penetrate to inaccessible zone are increased. Finally, reservoir with high vertical permeability results in high steam-oil ratio in the early period, which might lead to uneconomical condition. Steam trap technique must be applied together with hydraulic fracturing in order to prevent this situation.
DOI: 10.14457/cu.the.2015.201
title: Seismic performances of Mae Lao Bridge with elastomeric bearings and shear dowels

description: The research investigates the behavior of the Mae Lao Bridge, one of the damaged bridges, with elastomeric bearing and shear dowel. The objective of the research is to study the behavior of the bridge under different ground motion including the pier displacement, the girder displacement, the curvature of the column, and the stress-strain curve of the material including the confined, the unconfined concrete, and the reinforcement. Also, the effect of adding the elastomeric bearing and the shear dowel to the bridge is observed. In addition, the difference between the bridge with and without abutment soil spring is compared as well. The whole bridge is modeled using the computational program OpenSees. The bearings are modeled using linear model and the shear dowel as bilinear model; Columns are modeled with three separated parts: the rigid part, the plastic hinge part and the elastic part and so the beams. The analysis is focused on how the different thickness of bearing makes to the bridge structural reaction. The results show that the thicker thickness of bearing can help reduce the displacement of the columns, but increase the displacement on girders. The reduction of displacement on top of pier is about 10% to 25% from 2cm-thick bearing to 8cm-thick bearing of the wall-type piers. The curvature of the section is reduced as well even in some cases that the 8cm-thick bearing keep the section elastic without yielding. On the other hand, the shear dowel reaches its objective as well to help reduce both the displacement on top of pier and the girders if comparing to the case without shear dowels. Although other cases of different thickness of bearing help reduce the displacement and curvature of the column but still the 8cm-thick bearing case gives the best performances overall.