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Salinity effect on surfactant-assisted zinc oxide nanoparticles for enhanced oil recovery
No full textSeveral studies have focused on the advantages of applying nanotechnology to the enhanced oil recovery (EOR). This is because nanoparticles are unique due to their small size and large surface area. Metal oxide nanoparticles, including zinc oxide, have been proven to have favourable effects in EOR applications. However, the instability of nanoparticles is one of the most common issues. It has been established in the literature that using a surfactant with nanoparticles can stabilize the latter, lower the oil/water interfacial tension, and alter the wettability of reservoir rocks. It is also common knowledge that chemical EOR is affected by the salinity of formation water. Thus, the objectives of this study were to investigate the effects of salinity on zinc oxide nanoparticles with sodium dodecyl sulphate (SDS) over the interfacial tension and wettability, as well as to compare the recovery of oil by displacing sand packs with water, SDS, ZnO NPs with SDS, and the mixture of SDS, ZnO NPs, and NaCl. Particle size analysis (PSA) and zeta potential were determined to evaluate the size and stability of ZnO NPs before and after adding SDS. The surface tension for SDS was measured to identify the critical micellar concentration (CMC). The interfacial tension and contact angle were measured for different concentrations of nanofluid at ambient temperature and pressure. The concentration range for ZnO NPs was 0.02 to 0.1 wt%, while that for NaCl was 1000 to 30,000 ppm. The results showed that the size of the zinc oxide nanofluid decreased from 406.6 to 308.3 nm after adding SDS. The stability of ZnO nanofluid was confirmed to be improved after mixing with SDS through zeta potential readings of -11.1 mV to -53.3 mV. The CMC for SDS was recorded at 0.2 wt%. The optimum IFT value of 6.25 mN/m was obtained using a mixture of 0.2 wt% SDS, 0.06 wt% ZnO NPs, and 30,000 ppm NaCl. Meanwhile, the lowest contact angle of 45.6 º was achieved using a mixture of 0.2 wt% SDS, 0.06 wt% ZnO NPs, and 20,000 ppm NaCl. Oil recovery after water flooding was 36.1% of the original oil in place (OOIP), while the oil recovery after SDS flooding and SDS with zinc oxide NPs flooding recorded 52.3% and 58.3% OOIP, respectively. Ultimately, the mixture of SDS, zinc oxide NPs, and NaCl can recover up to 60.5% OOIP. The nanofluid mixture was found to be effective in EOR applications
Dual band textile antenna on artificial magnetic conductor for on-body communication applications
No full textThe integration of wearable devices on human body in Wireless Body Area Network (WBAN) offers new favourable and assistances. The properties of human body causes high transmission loss in the wearable antenna. In WBAN, the antenna and the artificial magnetic conductor (AMC) is needed to be flexible and comfortable to wear. Efficient wireless networking system depends on reliable tranmission between antennas. Textile dual-band AMC is developed as a ground plane to improve wireless on-body transmission. It offers clear on-body transmission path with increased antenna’ performances. The proposed wearable antennas and AMC jacket are purely textiles, which makes it convenient for wearable communication. In this thesis, the performance of single-band and dual-band textile antenna with and without dual-band AMC are studied in terms of radiation characteristic, reflection coefficient and transmission path. The antennas and AMC are designed to be operated at 2.4 GHz and 5.8 GHz. From the experiment, the characteristics of textile dipole antennas are altered when placed on the AMC sheet. The radiation characteristics and bandwidth of the antenna for both frequencies follow the AMC behavior while the gain of the antenna is increased about 4 dB. The radiation pattern of the antenna becomes directive when placed on the AMC sheet. Then, several experiments of transmission between antennas are conducted to test the reliability of the communication. Different antenna’ orientation and placement are considered. A maximum gain of 15 dB is achieved when the antenna is placed in a horizontal and vertical orientation. Finally, three types of jackets which are normal, ground and AMC jackets are fabricated. The transmission between antennas on those jackets are compared. Significant transmission enhancement is observed when both antennas are placed on the AMC jacket and vice versa to when the antennas are placed on the ground jacket. It shows a 15 dB S21 transmission improvement compared to transmissions on the normal jacket. Moreover, the AMC jacket offers outwards directional radiation pattern from human body with high gain. In addition, the textile bending measurement is also investigated. It is found that the textile bending gave no significant effect to the antennas and AMC sheet performance. In conclusion, the dual-band textile antenna and dual-band AMC jacket are successfully developed
Development of integrated renewable energy system for sustainable energy supply at Mai Farm Kalumpang Selangor
Full text linkMalaysia introduced renewable energy as the 5th fuel strategy in the energy-mix under the National Energy Policy in 2001. Malaysia has huge potential renewable energy resources in the form of solar, pico hydro and wind due to its geological characteristic and proximity to equator. Mai Farm in Kalumpang, Selangor is planning to implement a small scale integrated Solar PV, pico hydro, and wind for electricity to power up its facilities. The site has an average solar irradiation at 5.85 kWh/m2/day with the highest solar irradiation at 6.08 kWh/m2/day for month of October which is potential for implementation of solar PV system. The highest wind speed recorded is 5.58 m/sec on month of June. The average wind speed is 4.86 m/sec. The site has a consistent and continuous velocity of water flow coming from the nearest hill via gravity fed 3” PVC pipeline system. This research objective is to investigate the potential energy can be generated and to design an integrated renewable energy system consisting of floating solar PV, pico hydro and wind. The methodology of the research started by gathering data for geographical and meteorological information such as location, elevation, solar irradiation, wind speed and flow data for pico hydro. The load list for Mai Farm also investigated for demand and consumption. All the collected data is used as input to perform simulation and optimization of renewable energy system configurations by HOMER software. Different off-grid configurations of the integrated system proposed are investigated for its levelized cost of electricity (LCOE). The simulation shall be able to assess levelized cost of electricity (LCOE), CO2 avoidance and excess electricity resulting of the integrated renewable energy system
Energy efficiency improvement and renewable energy implementation for copra oil extraction process
Full text linkThe global demand for coconut oil has become more as the shortage of raw material and war happening across the world. Each country needs to find or ensure they have adequate supply of food for the internal usage. The current copra oil extraction method is similar to other seeds available which is using the expeller press method. The process has been in the market for very long and has been used by most of the copra producers. To ensure the market player has a more competitive processing plant in terms of energy efficiency and less impact to the environment, this research help to fill the major gap which helps to reduce the impact. To do benchmarking and to obtain live data, the suitable key energy consumption indicator is identified based on the performance of the current operational system and all necessary improvement is added as needed to increase the production rate while reducing the energy consumption of the overall plant. All data and information is collected based on actual operation of a plant. The plants performance has been monitored and a lot of improvement needed to be done on many part of the operational features. The main feature which we have studied and implemented is the additional plant which is called the “Solvent Extraction Plant”. The adding of this feature will actually increase the overall capacity of the plant by nearly 40% while maintaining or reducing the overall energy consumption of the plant by 5%-8%. Other than the above improvement, Renewable energy is also implemented on the plant. 2 type of RE is implemented which is the Solar power system which will substitute or reduce the usage of the Grid supply by 5% with the available space. The capacity of the solar system can be optimized by increasing the space or changing the solar panel spec to a higher efficiency panels. As for the Biomass Boiler which is introduced to the plant, the main function to reduce the dependency on the bunker oil and to reduce carbon footprint. The biomass boiler is considered good for this plant as they have abundance of coconut shell which is underutilized at this moment. Thus we have the opportunity of fine tuning the copra extraction plant energy efficiency while increasing the overall capacity, our main aim is to improve and extend the same solution or technology to other Copra extraction plants in Malaysia. Even if a lot of players are aware of the technology but they have not implemented on the solution because of lack of experience and working models
Process improvement and energy saving measures for sewage treatment plant
Full text linkEnergy in sewage treatment plant (STP) show the differential energy consumption on various stages which it depends on the indicator of the findings. To do comparison and benchmarking, the suitable key energy consumption indicator need to identify, and the suitable method need to formulate in performing the energy. This study is to perform energy saving measures (ESM) and process improvement for the STP. The study started with planning to select the STP and study on the potential of method to use. Sites visit then conducted to make an overall overview of STP and the related data was collected to do analysis. The propose ESM and process improvement analyzed in term of results feasibility, findings, and economic analysis. Introducing the Solar PV systems by do comparison type of panel and area available will determine the potential of savings. Retrofitting the lighting for existing 36W fluorescent to LED T8 14W and for 300W spotlight to 150W LED spotlight also help the STP to reduce the energy consumption. Retrofitting the Sequencing Batch Reactor (SBR) to produce biogas and the development of Combine Heat and Power (CHP) plant to generate electricity will reduce the demand of electricity from the grid. The waste heat produced later can be used for sludge dewatering process. Sludge utilization will help the STP to generate yearly income rather than allocate budget for the sludge removal from the STP. The overall result which is categorized according to the options will the analyzed to perform the best selected option. The best option is to utilize all the available potential area of Solar PV installation along with another ESM and utilization to obtain the best result. The combination of proposed improvement being analyzed according to the selected option, economic feasibility, energy savings, CO2 reduction and simple payback period with expected reducing the energy consumption and cost at the STP. As conclusion, the implementation of all the propose ESM and utilization will lead the savings in many aspects of area to the STP
Multimodal assessments of acupressure in muscle fatigue of forearm
No full textAcupressure is an alternative traditional Chinese medicinal practice believed to restore blocked internal energy or qi by applying manual pressure to specific points on the body and acts as an intervention strategy to improve muscle performance. Previous studies found that acupressure is an effective alternative medicinal practice in treating certain diseases, but the physiological reaction of the muscle is still unclear. Thus, this study aimed to conduct multimodal assessments that include the effectiveness of stimulation on acupressure in muscle fatigue of the forearm. Thirty subjects were randomly divided into two groups. The first group (n=15) received acupressure intervention, while the second group received kneading massage and act as a control group (n=15). During the acupressure intervention, the subjects received acupoints located at LI 4 (Hegu) and LI 11 (Guchi), and the acupoints were performed for 15– 30 seconds per attempt for 2–3 minutes on the brachioradialis muscle of the forearm. On the other hand, the control group received the kneading massage technique for 2– 3 minutes on the forearm after completing the 2 sets of 5 squeezed hand grip exercises within 15 – 30 seconds by using an adjustable hand grip exerciser. The results of the intervention group showed that there were significant differences in the levels of calcium, sodium, and potassium ions from about 0.01 mmol/l to 0.08 mmol/l. As for the lactic acid results, there was a change between 0.02 mmol/l and 0.08 mmol/l and the mean p-value is 0.05. Meanwhile, the mean value on the Fatigue Assessment Scale (FAS) was between 2.67 before acupressure and 2.99 after acupressure. The decreases in FAS after acupressure indicate that the level of fatigue in the forearm is mild. In addition, the electromyography (EMG) analysis before and after acupressure to the intervention group shows that the mean of descriptive analysis is 0.56 and 0.58, which indicates that the median frequency of nerve conduction velocity values between 0.064 mV and 0.901 mV of muscle contraction during muscle fatigue is quicker after acupressure has been applied. In conclusion, acupressure is effective to treat muscle fatigue by indicating the increased levels of calcium, sodium, and potassium ions as well as lactic acid. On the other hand, the Fatigue Assessment Scale supported that there was significance in measuring the level of muscle fatigue. Furthermore, EMG is proven to be able to measure the physiological reaction of nerve conduction velocity of the muscle on acupressure. Therefore, acupressure shows potential for further research regarding the effectiveness, implications and applications of acupressure toward the mechanism of muscle fatigue
Imporved characteristics of optimized YTTRIA-stabilized zirconia thin film grown using sol-gel dip-coating technique
No full textClean and sustainable energy production has become the priority of the 21st century to save Earth’s environment from ever-increasing pollution and climate change. Solid Oxide Fuel Cell (SOFC) is one of the emergent technologies that which can produce a vast amount of clean energy using water; thus, considered to be renewable, sustainable, and pollution-free. All previous studies have used high-temperature SOFC electrolyte preparation methods which were expensive and cumbersome. Based on these factors, in this study, good quality yttria-stabilized zirconia (YSZ) electrolyte thin film was synthesizing using soda lime glass and sapphire as a substrate by sol-gel dip-coating method which use low temperature preparation method for YSZ thin film. Several solvents were tested to obtain homogeneous suspension of YSZ such as water, acetone and alcohol and it was found out that alcohol is the suitable one. The samples then were characterized by diverse analytical techniques to determine their potency for the SOFC applications. As-deposited thin films were characterized using X-ray diffractometer (XRD) analyses, atomic force microscopy (AFM), Raman spectroscopy, field emission scanning electron microscopy (FESEM) and Four-point probe techniques. The impact of various substrates, sintering temperatures and layer-count on the structural, morphological and electrical properties of these electrolyte thin films was evaluated. Furthermore, the optimum thin film was chosen to demonstrate its viability as an effective SOFC electrolyte. XRD analysis showed that the YSZ thin films deposited on soda-lime glass and sapphire were highly amorphous and crystalline in nature, respectively. Hence, the sapphire substrate was selected for further deposition of thin films. To improve the overall characteristics of the YSZ films, two types of heat treatments like sintering and normalizing, were performed. The film which had been sintered at 1300 °C revealed the formation of crystallites with lower density than the normalized film. Conversely, the film which had been sintered above 1300 °C showed much better morphology compared to those obtained using the normalized heat treatment. The single-layer YSZ film which had been sintered at 1300 °C exhibited excellent crystallinity, dense morphology with fewer cracks, very low porosity and high electrical conductivity (2.905 S/m). The double-layered YSZ film sintered at 1400 °C displayed the highest conductivity (3.552 S/m) and best crystalline density (5.976 g/cm3). An increase in the number of layers from three to ten was found to degrade the crystallinity, density and morphology of the grown films. The YSZ electrolyte films deposited with up to three layers were not suitable for practical use in the SOFC. Therefore, the double-layered film which had been sintered at 1400 °C was chosen as the optimum film. The growth of the proposed films was explained using various mechanisms to provide new insight into the preparation of the YSZ electrolyte thin films with tailored properties via the low-cost and simple method at low temperatures. This study focused only on two types of substrates, a few sintering temperatures and one preparation method. However, another synthesis method, substrate and characterization technique such as spin-coating, porous anodic alumina and UV-Visible absorption or emission spectroscopy, respectively, may be useful for better sample optimization. The use of lower temperature for the deposition of the thin films can yield higher electrical conductivity of the electrolyte useful for room temperature operation of SOFC. Based on the results it can be concluded that the interplay of the type of substrate, sintering temperature and the number of coating layers plays a vital role in obtaining high-quality electrolyte thin film, showing that synthesis of the YSZ thin film is essential thus the best sample is established
Friction stir welding with different tool profiles on structure and hardness of dissimilar aluminium alloy AA5083 and AA6061-T6
Full text linkUnderwater dissimilar friction stir welding (FSW) of an aluminium alloy AA5083 and AA6061-T6 in butt joint configuration was studied. Underwater FSW is the solid-state joining operation that utilises the non-consumable tool to connect two facing workpieces without melting the workpiece substance in the underwater environment. Defect has been proven to have negative impact on overall welding engagement. It is becoming an area of increasing concern in any type of manufacturing, including welding. The present study continually looked for ways to manufacture the best underwater FSW tool pin profile for specific applications while minimising the different welding defects. The experimental method was to choose 1 sample among underwater FSW and normal FSW fabricated according to the welding process parameter and met the research criteria based on comparable studies. In addition, optical microscopy was employed to observe the microstructures and welding defects of the joints. The effects of the different tools at three profiles of straight, threaded, and tapered cylindrical tools on the structure and hardness of the joint dissimilar aluminium alloy were investigated. The presence of water is an excellent alternative to enhance durability and reduce the various types of welding defects during the welding process changes occurring in underwater FSW and normal FSW. These results have been used to understand the variation in the welding strength and the microhardness obtained in underwater FSW and normal FSW at both different tool pin profiles and values of welding speed. Results have revealed the presence of various types of defects such as groove and tunnel defects in the weld region. Metallurgical macrostructure observation on the underwater FSW and normal FSW samples revealed the presence of welding defects which were groove and tunnel in the stir zone. The tapered cylinder pin profile and 60mm/min welding speed remarkably affected welding textures resulting in a higher hardness value than the other samples. Furthermore, the optimal combination of rotational speed and welding speed can significantly improve the hardness strength of the welded joint. The study indicates that underwater FSW was achieve 77.56 HV, which is supported by the result obtained. This number was 18% greater than the hardness value achievable with the normal FSW, 63.30 HV. For underwater FSW, higher rotational speed and welding speed were suggested to establish sound welded dissimilar joints and achieve better microstructures which could collectively improve the welding strength
Photocatalyst composites of zinc oxide-doped titanium dioxide modified with sodium silicate for antibacterial applications
Full text linkSuperbugs have troubled and challenged mankind since the development of antibiotics could not keep up with the rate of bacterial evolution. To avoid cross-contamination, the emphasis should be placed on effective protection beginning with the surroundings. This study concentrated on the rapid sonochemical synthesis of photocatalyst sodium silicate loaded titanium dioxide and zinc oxide (TiO2@ZnO_Na2SiO3) composites as an antibacterial agent using short synthesis time and less hazardous solvents. Anatase was obtained as evidenced by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analyses. Meanwhile, bonding present between the main element of the synthesized sample were confirmed by Fourier transform infrared spectroscopy (FTIR). Visible range was obtained for TiO2@ZnO samples while near ultraviolet range was obtained for TiO2@ZnO_Na2SiO3 samples as depicted by diffused reflectance ultraviolet-visible spectroscopy (DR UV-Vis). All TiO2@ZnO have lower recombination rate compared to ZnO whereas all TiO2@ZnO_Na2SiO3 samples have lower recombination rate compared to TiO2@ZnO (TiO2:ZnO = 1:0.1) composite as observed under fluorescence spectroscopy. All composites have irregular shape as noticed under scanning electron microscopy (SEM). Variation of ratios in TiO2:xZnO (x = 0.1, 0.2, 0.3, 0.4, and 0.5) and TiO2@ZnO_yNa2SiO3 volume percent (y = 2, 4, 6, 8, and 10) were made to obtain the best ratio for highest antibacterial activity. [email protected] was determined to be the optimal ratio by evaluating both physiochemical properties and antibacterial performance. [email protected] had a bacteria killing efficiency (BKE) of 78.68% against S. aureus and 99.99% against E. coli, due to its smallest crystallite size (55 nm), lowest band gap energy (2.68 eV), and lower recombination rate. The optimal ratio of TiO2@ZnO_10Na2SiO3 was obtained after further modification of previous ratio of [email protected] with Na2SiO3, which achieved a lower band gap energy (3.10 eV) and the lowest rate of recombination amongst other variants, with a BKE of 81.36% against S. aureus and 99.99% against E. coli. As seen under HRTEM image and amorphous XRD pattern, the loading of Na2SiO3 outside of TiO2@ZnO was successful. Therefore, this study has successfully synthesised a new antibacterial agent TiO2@ZnO_Na2SiO3
Flexible organic polymer matrix composite antenna for wireless local area network application
Full text linkThe growing demand for flexible antennas has resulted in intensified research on new materials for flexible antennas. The flexibility of antennas is a well-known requirement in wireless body area networks (WBAN), vehicle navigation system and wireless local area networks (WLAN) to improve seamless integration on devices. Compared with conventional rigid antennas, conformal antennas provide a larger coverage area with a broad beam radiation pattern due to the increase in the area of transmission and reception. This research aims to develop and explore a new organic polymer matrix composite (PMC) antenna with organic fibre to replace synthetic polymer composite which may release harmful chemical and also non-biodegradable. Organic PMC is not only low cost but able to promote sustainability for the environment. Size miniaturization also needs to be achieved for a more compact size antenna and also to enhance the bandwidth. The proposed antenna is a flexible monopole antenna based on organic PMC material produced from natural Basalt fibre and it proved to manage in operating at frequencies of 2.45 GHz and 5.8 GHz for WLAN application. The characterized Basalt composite substrate has a thickness of 0.42 mm, dielectric constant of 3.105 and tangent loss of 0.0299. The vacuum infusion technique is used to manufacture the composite material as this technique can increase the accuracy of fiber to resin ratio and give consistent resin usage. Before vacuum infusion, a layer of conductive fabric named ShieldIt with adhesive glue on its bottom layer will be ironed onto the basalt fiber fabric. Then, two layers of basalt fiber fabric with a layer of conductive fabric on the top layer were placed on the mold before vacuum conditions are created. Epoxy resin and hardener were then mixed in a ratio of 10:6. Vacuum pressure was turned on and pushed the epoxy mixture to the laminate through the tubing. The defected ground structure (DGS) were implemented to improve bandwidth and coplanar waveguide (CPW) as antenna feeding method. Top layer radiating element is conductive fabric and the lasercut machine cut out the antenna pattern precisely. Measured antenna gains at 2.45 GHz and 5.8 GHz are 3.865 and 4.8 with efficiency of 62.63% and 68.07%, respectively. As a flexible antenna, the bending test proved that the antenna performance did not compensate for bending at different curvature radii