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Multi-wavelength brillouin fiber laser by utilizing fiber bragg grating
No full textMaster of Science in Microelectronic EngineeringA ring cavity multi-wavelength Brillouin fiber laser by utilizing fiber Bragg grating is evolved to increase the transmission or data rate in the optical fiber communication especially in dense wavelength division multiplexing system. The combination of stimulated Brillouin scattering effect and fiber Bragg grating’s reflectivity enhances the multi-wavelength generation in order to transmit a lot of information at the same time. A ring cavity configuration has been experimental demonstrated with different single mode fiber lengths in which act as a Brillouin gain medium in stimulated Brillouin scattering effect. The amplified Brillouin pump power of 8 dBm to 18 dBm with a step increment of 1 dBm was applied in the laser system. Five different single mode fiber lengths of 8 km, 9 km, 10 km, 11 km and 12 km with nine output coupling ratios of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 90% were optimized to generate more output signals. Overall, the results showed that the investigation of Brillouin threshold power for first Brillouin Stokes signals was critically depends on the selective single mode fiber lengths and output coupling ratios. The lowest Brillouin threshold power of 8 dBm was achieved when 10%, 20%, 30% and 40% of the output coupling ratio at 10 km of single mode fiber was applied into the ring cavity while the highest Brillouin threshold power of 12 dBm was recorded by using 8 km of single mode fiber with 60%, 70%, 80% and 90% of output coupling ratios. Besides that, up to maximum 38 generated Brillouin Stokes signals with 16.00 dB of average optical signal to noise ratio value were recorded at 1550 nm of Brillouin pump wavelength when high amplified Brillouin pump power of 18 dBm was injected into the ring cavity. An optimum output coupling ratio of 90% and 10 km of single mode fiber were utilized in producing the multi-wavelength generation. The wavelength selectivity based on the Fiber Bragg Grating’s properties constrains the tuning range ability of this laser system. The multi-wavelength generation only occurred within 1544 nm to 1556 nm of Brillouin Pump wavelength according to the 3 dB bandwidth of 5 nm of the fiber Bragg grating. In short, the better performance of multi-wavelength Brillouin Fiber Laser by utilizing fiber Bragg grating was successfully demonstrated whereby the most multi-wavelength generation produced at 10 km of the effective Brillouin gain medium
A comparative study on whole body vibration (WBV) comfort towards Perodua's compact car model through Monte Carlo simulation
No full textMaster of Science in Engineering MathematicsThe objective of this research is to study the vibration which generate in the cabin of the car and seek for the vibration comfort level between all three cars to compare car which has a finest level of comfort between this three cars. In this study, the level of vibration in the cabin of the three car engine speed as measured by car respectively. Vibration generated during experiments in the cabin cars is recorded and stored in the form's data and the test in two circumstances, namely, state of stationary and is not stationary. When in a situation not stationary vibration resulting in the car taken during guided through three types of road namely highway, pavement and urban. A programming system developed to record the generation of vibration in the cabin of the car. Data collected that have been collected will be go through some process start with methods evaluation vibration and regression analysis. An equation will be approach through the analysis to find the significant data that can be used in the process which is K-Means algorithm. Based on the trends of the experienced and exposed vibration, the model is able to differentiate the level of comfort between the clusters by grouping the level of sound vibration into five categories which are most pleasant, medium pleasant, marginal, medium annoying and most annoying. To review the accuracy of classification data cluster, the K-Nearest Neighbor method and Linear Discriminant Analysis is used for shows the percentage accuracy of classification data have been cluster. Later, the vibration for the three cars in this study which has analyzed, compared using the approach of analysis of variance (ANOVA)
Production of sea mango (Cerbera Odollam) based activated carbon for CO2 adsorption
No full textMaster of Science in Environmental EngineeringThe activated carbon utilization for carbon dioxide (CO2) adsorption process is a promising method to reduce the emission of CO2. The activated carbon was produced from the non-edible sea mango (Cerbera odollam) fruit through sequential chemical and physical processes. There were two methods of activated carbon preparation; i.e. Method 1: the precursor was impregnated with phosphoric acid (H3PO4) and then thermally activated at 500 °C with different activation atmosphere for 2 hours, Method
2: the precursor was heated at 200 °C with nitrogen gas (N2) flow prior to chemical and thermal activation processes as performed in Method 1. Porous structures were developed on the surface of the activated carbon due to the physicochemical activation process and proven by surface morphology study. The best virgin activated carbon prepared by double-stage activation via Method 2 in the absence of any gases (RCIHM2-A) which recorded the highest BET surface area (1475.43 m2/g), iodine
adsorption capacity (1040.58 mg/g) and the highest carbon element (79.17 %). The activation process was further confirmed to happen with the unchanged and/or disappearance of C-H and -C≡C-H:C-H of the functional group at peaks 2936.73 cm-1
and 617.76 cm-1 as compared to raw sea mango sample. The prepared mesoporous activated carbon with pore diameter 2.86 nm was then modified with amine-based chemical (AMP, PZ, MEA, and DEA) impregnation to improve its adsorption capability
and selectivity to adsorb CO2. Physisorption process which has weak Van der Waals forces interaction between CO2 molecules and pores on virgin activated carbon surface has been transformed to chemisorptions process (covalent bond) via amine
impregnation. The performance of the activated carbon on CO2 adsorption was obtained through breakthrough time curve and adsorption capacity. The reduction of BET surface area was approximately 56 % to 62 % after amine impregnation proved that amine molecules successfully attach on the activated carbon surface. The result was further confirmed by SEM images which illustrated that amine molecules filled up most of the activated carbon pores. The best amine functionalized on carbon surface was 2-amino-2-methyl-1-propanol (AMP) with highest CO2 adsorption capacity 23.05 mgCO2/gsorbent and has been able to achieve 94.47 % of regeneration. The nitrogen (N) element measurement via elemental analysis by EDX was enhanced two-fold (from 4.73% to 7.25 %) after impregnated with this AMP amine and confirmed by the existence of N-H bond at 3391.22 cm-1 and C-N bond at 1173.19 and 1047.55 cm-1, respectively. The result indicated that elemental N functionalized activated carbon surface for CO2 adsorption. The effect of other operating parameters such as the lowest inlet flow rate (5.00 mL/min) and sample loading (2.00 g) recorded the highest CO2 adsorption capacity, 23.05 mgCO2/gsorbent, and 28.18 mgCO2/gsorbent, respectively, whilst CO2 adsorption capacity was inversely proportional to inlet flow rate and adsorbent loading increment
Modelling and simulation of respiratory effort in energy harvesting using Matlab
No full textMaster of Science in Electrical Power EngineeringEnergy harvesting from human power is investigated without being fully dependent to the DC sources. Respiratory effort is chosen as an energy harvester in order to prove the capability of human respiratory effort in producing the energy which can be used as the other alternative in powering low power electrical devices. Besides, the energy from human body can be generated 24 hours daily without having any limitation as the human is continually breathing even during sleep. The generated power carried out as the electromagnetic generator is worn on the human chest because the generator can be operated when there is a motion of the chest wall during the inhalation and exhalation processes. The respiratory effort is modeled and simulated using Matlab/Simulink software. A few conditions of breathing are being considered in order to examine different output power from the system. From the result obtained throughout the simulation, it can be proven that the human respiratory effort can produce energy through harvesting technique. The energy harvesting method produced 6.17 mW of the output power from an adult. Moreover, the output power increases as the breathing rate increases
Analysis of muscle activity during contractions in the three heads of the triceps branchii using surface electromyography
No full textDoctor of Philosophy in Biomedical Electronic EngineeringAmong all the upper extremity skeletal muscles, the three headed (lateral, long and medial) triceps brachii (TB) is considered as the muscle most responsible for normal and sports activities. In this research, we recorded and evaluated muscle activity among the three heads of TB, using surface electromyography (sEMG) signals, during isometric and isotonic contractions. The commercially available Delsys and PowerLab data acquisition systems were used to record the EMG signals. Isometric contractions were produced by a forceful handgrip task with full elbow extension. 2 different protocols were applied –
repetitive isometric contraction and prolonged isometric contraction. 13 participants performed 5 trials, 10 s each, to observe behavior between and within contractions, and 18 participants performed a single trial of 90 s to observe fatiguing effects. On the other hand, isotonic contractions were investigated during a cricket bowling action. 2 different bowling categories were studied – fast bowling (FB) and spin bowling (SB). 10 participants performed 3 overs (1 over = 6 ball deliveries) equivalent to 18 trials for both FB and SB. For the statistical analysis, we computed the mean of the normalized root mean square (RMS) values across all subjects from the collected data. We found muscle activity among the three heads of TB, between repetitive isometric contractions, to be statistically significant (p < 0.05). Muscle activity decreased in the lateral and long heads, but however
increased in the medial head. In the case of within contractions, TB muscle strength decreased with increasing contraction duration, and the lowest decrease of muscle strength was observed in the medial head. Results from the prolonged isometric contraction show a gradual decrease in the computed mean of the normalized RMS values across all subjects after a certain time period, indicating the presence of fatigue. Time to fatigue was observed at the lateral, long and medial heads at 50 s, 40 s and 65 s respectively. Fatiguing rates was observed at the long, medial and lateral heads at a slope of -2.863, -2.412 and -1.877
respectively. On the other hand, during the isotonic contractions, we found that the sEMG activities among the three heads of the TB and among the 7 phases of bowling to be statistically significant (p < 0.05). Among the 7 phases, the front-foot contract (FC) phase generated the highest sEMG activity during both FB and SB. We also found that all the heads of the TB were more active in FB than SB. Moreover, the medial head was found to be more active compared to the other heads during all the 7 phases of bowling for both FB and SB. The outcomes of the present research may play a key role in our quest to better understand the physiology and biomechanics of the TB muscl
