IIUM Engineering Journal
Not a member yet
783 research outputs found
Sort by
Efficient and Compact Optical Amplifier Using EYDF
No full textAn efficient Erbium/Ytterbium doped fiber amplifier (EYDFA) is demonstrated using a 1058nm pumping wavelength, where the amplification is assisted by energy transfer between Yb and Er ions. The energy transfer increases the limit of erbium doping concentration that is imposed by concentration quenching in Erbium-doped fiber (EDF). Therefore, the gain and noise figure are severely degraded with 1480 nm pumping, where the energy transfer cannot be achieved. The use of optical isolator improves the small signal gain and noise figure by about 4.8 dB and 1.6 dB, respectively. By employing a double-pass configuration, a higher gain can be obtained with an expense of a noise figure penalty. The gain improvement of 17.0 dB is obtained at 20 mW and -50 dBm of pump and input signal powers. This shows that the double-pass configuration is an important aspect to consider when designing an efficient EYDFA
Direct Bioconversion of Oil Palm Empty Fruit Bunches for Bioethanol Production By Solid State Bioconversion
No full textThe bioethanol production was conducted by utilizing agriculture waste, palm oil empty fruit bunches (EFB) with the aid of T. harzianum and yeast, Saccharomyces cerevisiae using solid state bioconversion method. The compatibility of various fungal strains was done as to develop the direct bioconversion process of compatible mixed culture. Analyzes such ethanol estimation, reducing sugar and glucosamine as growth indicator were conducted in order to select the best experimented run for optimization. The optimization of process conditions, by using central composite design (CCD) was carried out. Optimization of process condition was done with varied level of moisture content, pH, inoculum size, concentration of co-substrate (wheat flour) and mineral solutions. Statistical analysis showed that the optimum process condition for moisture content was 50% (v/w), pH of 4, inoculum size of 10% (v/v), concentration of wheat flour of 1% (v/v) and mineral solutions 1%(v/v). In this study, the application levels of the methods of environmental management in regards to the maximum production were determined. The final optimization with the developed process conditions indicated that the maximum production was increased from 14.315 (v/v) to 34.785(v/v)
DECOY STATE QUANTUM KEY DISTRIBUTION
Get PDFExperimental weak + vacuum protocol has been demonstrated using commercial QKD system based on a standard bi-directional ‘Plug & Play’ set-up. By making simple modifications to a commercial quantum key distribution system, decoy state QKD allows us to achieve much better performance than QKD system without decoy state in terms of key generation rate and distance. We demonstrate an unconditionally secure key rate of 6.2931 x 10-4per pulse for a 25 km fiber length
PREDICTION OF SIGNAL ATTENUATION DUE TO DUSTSTORMS USING MIE SCATTERING
Get PDFThe present trend in radio design calls for the use of frequencies above 40 GHz for short links carrying wide-band digital communication signals. In order to utilize the new frequency band efficiently, signal attenuation studies due to duststorms is needed urgently for desert areas. This paper presents a mathematical model which has been developed to predict the signal attenuation due to duststorm. The proposed model enables the convenient calculation of the signal path attenuation based on Mie solution of Maxwell's equations for the scattering of electromagnetic wave by dust particles. The predicted values from the proposed mathematical model are compared with the measured values observed in Saudi Arabia and Sudan and show relatively close agreement
A STUDY OF COMPARTMENT FIRE UNDER FORCED VENTILATION: EXPERIMENTAL AND COMPUTATIONAL FLUID DYNAMICS MODELING
No full textThis paper discusses on the dynamic behavior of the flame and smoke inside a compartment fire. The compartment can be referred to a room, road tunnel, duct, compartment or a building. A series of small scales experiments were carried on four rectangular ducts that have the same height (250 mm) but different widths (125 mm, 250 mm, 500 mm and 1000 mm). Fire simulations on the same compartments were performed to investigate the effectiveness of Computational Fluid Dynamics (CFD) in predicting fire phenomenon. CFD was found capable to predict fire phenomenon such as flame shape, flame height and flame tilt angle similar to the experiment
CHARACTERIZATION AND MODELING OF SOLITON TRANSMISSION AT 2.5 GB/S OVER 200 KM
No full textSoliton characteristics and soliton transmission have been simulated using a VPI simulator. Simulation was also used to construct and study a soliton communication system. Near soliton pulses emitted by an actively mode-locked laser is then compressed in a dispersion-compensating fiber (DCF) to produce solitons. The effects of non-linearity and active pre-chirping of mode-locked laser diode sources were also investigated. Assessment on a modeled system using real data shows that propagation over 250 km at 2.5 Gb/s in standard fibers with 20 ps pulse widths is possible in the 1550 nm wavelength range
NEW CLUSTERING SCHEMES FOR WIRELESS SENSOR NETWORKS
Get PDFIn this paper, two clustering algorithms are proposed. In the first one, we investigate a clustering protocol for single hop wireless sensor networks that employs a competitive scheme for cluster head selection. The proposed algorithm is named EECS-M that is a modified version to the well known protocol EECS where some of the nodes become volunteers to be cluster heads with an equal probability. In the competition phase in contrast to EECS using a fixed competition range for any volunteer node, we assign a variable competition range to it that is related to its distance to base station. The volunteer nodes compete in their competition ranges and every one with more residual energy would become cluster head. In the second one, we develop a clustering protocol for single hop wireless sensor networks. In the proposed algorithm some of the nodes become volunteers to be cluster heads. We develop a time based competitive clustering algorithm that the advertising time is based on the volunteer node’s residual energy. We assign to every volunteer node a competition range that may be fixed or variable as a function of distance to BS. The volunteer nodes compete in their competition ranges and every one with more energy would become cluster head. In both proposed algorithms, our objective is to balance the energy consumption of the cluster heads all over the network. Simulation results show the more balanced energy consumption and longer lifetime
FORWARD MASKING THRESHOLD ESTIMATION USING NEURAL NETWORKS AND ITS APPLICATION TO PARALLEL SPEECH ENHANCEMENT
Get PDFForward masking models have been used successfully in speech enhancement and audio coding. Presently, forward masking thresholds are estimated using simplified masking models which have been used for audio coding and speech enhancement applications. In this paper, an accurate approximation of forward masking threshold estimation using neural networks is proposed. A performance comparison to the other existing masking models in speech enhancement application is presented. Objective measures using PESQ demonstrates that our proposed forward masking model, provides significant improvements (5-15 %) over four existing models, when tested with speech signals corrupted by various noises at very low signal to noise ratios. Moreover, a parallel implementation of the speech enhancement algorithm was developed using Matlab parallel computing toolbox
COMPENSATED INVERSE PID CONTROLLER FOR ACTIVE VIBRATION CONTROL WITH PIEZOELECTRIC PATCHES: MODELING, SIMULATION AND IMPLEMENTATION
No full textActive vibration control of the first three modes of a vibrating cantilever beam using collocated piezoelectric sensor and actuator is examined in this paper. To achieve this, a model based on Euler-Bernoulli beam equation is adopted and extended to the case of three bonded piezoelectric patches that act as sensor, actuator and exciter respectively. A compensated inverse PID controller has been designed and developed to damp first three modes of vibration. Controllers have been designed for each mode and these are later combined in parallel to damp any of the three modes. Individual controller gives better reduction in sensor output for the second and third modes while the combined controller performs better for the first mode. Simulation studies are carried out using MATLAB. These results are compared and verified experimentally and the real-time implementation is carried out with xPC-target toolbox in MATLA
E-WASTE: ETHICAL IMPLICATIONS FOR EDUCATION AND RESEARCH
Get PDF“E-waste” is a popular, informal name for electronic products nearing the end of their “useful life”. This includes discarded computers, televisions, VCRs, stereos, copiers, fax machines, electric lamps, cell phones, audio equipment and batteries. E-wastes are considered dangerous, as certain components of some of these electronic products contain materials; such as lead; that are hazardous, depending on their condition and density. If improperly disposed, E-wastes can leach lead and other substances into soil and groundwater posing a threat to human health and environment. Many of these electronic products can be reused, refurbished, or recycled in an environmentally sound manner so that they are less harmful to the ecosystem. This paper highlights the types and hazards of E-wastes particularly the computers’ waste. The dimensions and ethicality of the problem in the third-world countries are reviewed. The needs for the appropriate management of e-waste and options that can be implemented are discussed. After reviewing the Islamic concepts for environmental protection, ethical implications for curriculum development as well research directions are highlighted. Elements for a course on e-waste as well as some across-the-curriculum topics are proposed. This is specially tailored to suit the faculty of Engineering at the International Islamic University-Malaysia