Power Consumption Modeling and Analysis of Integrated Optical-Wireless Access Network

The integration of optical and wireless technologies at access networks are considered as a future solution which provide both high bandwidth and high mobility in an efficient way. GPON is a suitable candidate for optical backhaul due to the combination of higher data rates, greater split ratio and support for triple play services hence it offers maximum flexibility and cost advantages. On the other hand, recent developments of new radio access technologies and introduction of femtocell base stations provide the potential of offering broadband services and applications to everyone and everywhere. However, the power consumption of this network demands a particular attention because access networks are the largest contributor the network related electricity consumption. Therefore, in this paper we evaluate the power consumption of integrated optical-wireless access network which is based on independent ONU-BS architecture. We proposed a power consumption model for such network and the assessment has been done under different simulation scenarios. The constructed model will provide insight of the energy performance of the integrated access network so that in the network design process, focus can be done to the most energy saving strategies

Thermo-kinetic assessment of glucose decomposition to 5-hydroxymethyl furfural and levulinic acid over acidic functionalized ionic liquid

Decomposition of biomass feedstock is a promising technique for producing versatile chemicals such as 5-hydroxymethyl furfural (5-HMF) and levulinic acid (LA). Glucose, the model compound of cellulose, is one of the most important starting components for bio-based chemical synthesis. Herein, the kinetics of glucose decomposition catalyzed by an acidic functionalized ionic liquid, 1-sulfonic acid-3-methyl imidazolium tetrachloroferrate ([SMIM][FeCl4]) was studied in the temperature range of 110–170 °C. A simplified kinetic model was developed based on pseudo-homogeneous first-order reactions. The kinetic model consists of four main key steps: (1) dehydration of glucose to 5-HMF; (2) degradation of glucose to humins; (3) rehydration of 5-HMF to LA; and (4) degradation of 5-HMF to humins. The proposed model was in a good agreement with the experimental results. The evaluated activation energies for glucose decomposition to 5-HMF and 5-HMF decomposition to LA were 37 and 30 kJ·mol-1, respectively. The first-order rate constants were also used to calculate the thermodynamic activation parameters. The kinetic and thermodynamic parameters obtained can be applied to provide insights on the biomass decomposition to 5-HMF and LA using acidic ionic liquid

Assessment of natural radionuclides in rivers of Pahang State Malaysia

Investigations were conducted to determine the radionuclide concentration levels in the major rivers in Pahang state, Malaysia. Since the rivers are the main sources for water supply in the state, it is important to measure natural radionuclide concentrations in the rivers. Seventeen water samples were collected from major rivers in Pahang state. The concentration of uranium, thorium and potassium were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). The samples were found to contain permissible levels of radionuclides with a mean activity concentrations of uranium, thorium and potassium found to be 8.49 ± 0.34 mBq L-1, 1.74 ± 0.27 mBq L-1and 77.85 ± 0.96 mBq L-1respectively. The ratio between thorium and uranium concentration is found to be 3:4 due to the higher solubility of uranium than thorium in water. Radionuclide concentrations obtained were compared with the terrestrial gamma radiation dose rate measured around the area. A good relation was observed between uranium and thorium concentrations with gamma dose rate obtained around the area while no relation was found between the potassium concentrations with gamma dose rate. Significance of the results obtained is discussed

Esterification of levulinic acid to levulinate esters in the presence of sulfated silica catalyst

Levulinic acid (LA) is one of biomass derived building block chemicals with various applications. Catalytic esterification of LA with alkyl alcohol produces levulinate ester which can be applied as fragrance, flavouring agents, as well as fuel additives. In this study, a series of sulfated silica (SiO2) catalyst was prepared by modification of SiO2 with sulfuric acid (H2SO4) at different concentrations; 0.5 M to 5 M H2SO4. The catalysts were characterized, and tested for esterification of LA with ethanol to ethyl levulinate (EL). The effect of various reaction parameters including reaction time, catalyst loading and molar ratio of LA to ethanol on esterification of LA to EL were inspected. The catalyst with high concentration of acid sites seemed suitable for LA esterification to EL. Among the sulfated SiO2 catalysts tested (0.5 M-SiO2, 1 M-SiO2, 3 M-SiO2 and 5 M-SiO2), 3 M-SiO2 exhibited the highest performance with the optimum EL yield of 54% for reaction conducted at reflux temperature for 4 h, 30% 3 M-SiO2 loading and LA to ethanol molar ratio of 1:20. Besides, the reusability of 3 M-SiO2 catalyst for LA esterification with ethanol was examined for five cycles. Esterification of LA with methanol and 1-butanol were also carried out for methyl levulinate (ML) and butyl levulinate (BL) productions with 69% and 40% of ML and BL yields, respectively. This study demonstrates the potential of sulfated SiO2 catalyst for levulinate ester production from LA at mild process condition

Esterification of levulinic acid to levulinate esters in the presence of sulfated silica catalyst

Levulinic acid (LA) is one of biomass derived building block chemicals with various applications. Catalytic esterification of LA with alkyl alcohol produces levulinate ester which can be applied as fragrance, flavouring agents, as well as fuel additives. In this study, a series of sulfated silica (SiO2) catalyst was prepared by modification of SiO2 with sulfuric acid (H2SO4) at different concentrations; 0.5 M to 5 M H2SO4. The catalysts were characterized, and tested for esterification of LA with ethanol to ethyl levulinate (EL). The effect of various reaction parameters including reaction time, catalyst loading and molar ratio of LA to ethanol on esterification of LA to EL were inspected. The catalyst with high concentration of acid sites seemed suitable for LA esterification to EL. Among the sulfated SiO2 catalysts tested (0.5 M-SiO2, 1 M-SiO2, 3 M-SiO2 and 5 M-SiO2), 3 M-SiO2 exhibited the highest performance with the optimum EL yield of 54% for reaction conducted at reflux temperature for 4 h, 30% 3 M-SiO2 loading and LA to ethanol molar ratio of 1:20. Besides, the reusability of 3 M-SiO2 catalyst for LA esterification with ethanol was examined for five cycles. Esterification of LA with methanol and 1-butanol were also carried out for methyl levulinate (ML) and butyl levulinate (BL) productions with 69% and 40% of ML and BL yields, respectively. This study demonstrates the potential of sulfated SiO2 catalyst for levulinate ester production from LA at mild process condition

Analysis of signal propagation in an experiment room with epoxy covered floor for wireless sensor network applications

As sensor applications combined with wireless network becoming more of an everyday applications, the optimal deployment becomes ever increasing important as that would be a key important factor in the trade-off between cost and link quality. This paper reports on the effect of epoxy covered floor on signal propagation characteristics in an experiment room. Microchip developed motes were used to measure signal propagation in an experiment room where sensors would be deployed extensively. The results show that the signal strength for 30 cm antenna height provides a significant margin with respect to signal noise floor. As for the 5 cm antenna height, there is still around 25 dB margin in average before the signal reaches noise floor. Analysis shows that the log-distance model is the best fit to the measured data. Free Space Loss model seemed to under estimate the overall performance of the signals. An important conclusion from this study is that wireless mote deployment must consider the margin between the two signals of antenna heights and the margin to noise floor to avoid link quality deterioration especially for sensitive data acquisition applications

A mathematical model for wastewater treatment process of an oxidation pond

This study presents a mathematical model for wastewater treatment process (WWTP) of an oxidation pond. The model permits investigating the effects of a biological based product called mPHO on the degradation of contaminants as well as increase the amount of dissolved oxygen (DO) in the pond. At this aim, an ordinary differential equation with coupled equations has been developed to study the correlation between the amount of bacteria (phototrophic and Coliform), chemical oxygen demand (COD), and dissolved oxygen (DO) existing in the pond. The mathematical model is employed to simulate the behaviour of the system where the numerical results demonstrate that the proposed model gives a good approximation of the interaction processes that occur naturally between biological and chemical substances involved in the pond

A development of optical network unit power consumption model considering traffic load effect

Accurate and precise measurement of energy consumption for the deployment of fiber-to-the-home (FTTH) network using Gigabit passive optical network (GPON) is vital to the research community to develop models for the synthesis of energy-efficient protocols and algorithms for the access network. However, lack of power consumption measurement of optical network devices in the past has led to unrealistic and/or oversimplified model being used in simulations. Usually the access network devices are assumed always on and their consumption is both traffic and time independent. Therefore, in this paper we propose an experimentally-driven approach to i) characterize the Optical Network Unit (ONU) from the power consumption standpoint and ii) develop more accurate power consumption model for the ONU. We focus on ONU since it represents the main contributor to the energy consumption of optical access network. The real data in terms of the power consumption and traffic load have been obtained from continuous measurements performed on a GPON network testbed. The measurement is limited to a maximum 100 Mbps data rate due to a limitation in the sampling rate and precision of the measurement device. However, validation has been done with theoretical power consumption model in order to prove the feasibility of the proposed model. Our measurements show that the power consumption of the ONU exhibits a linear dependence on the traffic in which the power consumption at idle mode is 11.51 W while in low power mode the power consumption is around 7.52 W

Electromagnetic Field Interaction Between Overhead High Voltage Power Transmission Line and Buried Utility Pipeline.

yesThis work presents the development of a new approach of modelling the source excitation and the penetration of structures by continuous propagating electromagnetic (EM) plane waves. The technique incorporates the solution of time-dependent Maxwell¿s equations and the initial value problem as the structures are illuminated by the plane waves. The propagation of waves from source excitation is simulated by solving a finite-difference Maxwell's equation in the time domain. Subgridding method is used to condense the lattice at the point of interest locally for observing field distribution in high resolution. The computational burden due to huge number of time steps has been eased by employing quasi-static approach. An example of induced EM fields near an underground pipeline runs parallel to a 132 kV overhead power transmission line (OHTL) has been presented which paves the way in the development of new approach of EM fields interaction modelling.MSCR

Microstrip to Parallel-Strip Nonlinear Transition Balun with Stubs and DGS for UWB Dipole Antenna

Three tapered baluns with nonlinear transition are developed for harmonic suppression in dipole antenna. The first balun consists of an exponential profile with the size of a quarter–wavelength for both the height and width with a wideband characteristic. However, for some applications such as narrowband harmonic suppression antennas and wideband-to-narrowband reconfigurable antennas, the suppression of higher operating band is desired. By employing stubs-filter and a defected ground structure (DGS), two narrowband tapered baluns are produced. They are named as an exponential balun-stub and an exponential balun-DGS, respectively, that operate from 1 to 2 GHz. A simulated and measured results that based on the reflection coefficient is found to be better than -10 dB from 1 to 2 GHz. The employment of the stubs and DGS have enabled these baluns to have the capability to reject the unwanted higher frequency band from 2.0 to 10 GHz. Finally, the proposed baluns are employed as a feeding circuit for an ultra wideband (UWB) circular dipole antenna that produces a reasonable outcome