Showing papers by "Chittagong University of Engineering & Technology published in 2015"
TL;DR: In this paper, the authors discuss various existing treatment processes (mainly anaerobic and aerobic digestion, physicochemical treatment and membrane separation) and factors that influence the treatment methods and conversion of POME to renewable biogas such as biomethane and biohydrogen.
Abstract: Palm oil is an important edible oil in the global fats and oil market and its industry is also one of the prominent global agricultural industries. The production of crude palm oil reached 62.34 million tonnes in 2014. However, enormous volumes of production has subsequently discharged large volumes of a palm oil mill effluent (POME). POME is a remarkably contaminating effluent due to its high amount of COD, BOD and colour concentrations, which can affect the environment, especially water resources. However, it was recognized as a prospective source of renewable biogas such as biomethane and biohydrogen. Nowadays, with the global emphasis on sustainability, if we simultaneously operate wastewater treatment and produced renewable bio energy in the palm oil industry, then this industry can be environmentally sound, with cleaner production and greater sustainability. The aim of this review is to discuss various existing treatment processes (mainly anaerobic and aerobic digestion, physicochemical treatment and membrane separation) and factors that influence the treatment methods and conversion of POME to renewable biogas such as biomethane and biohydrogen on a commercial scale.
168 citations
TL;DR: The electrical properties of Ni0.27Cu0.10Zn0.63Fe2O4 (NCZF) prepared from auto combustion synthesis of ferrite powders have been studied by impedance and modulus spectroscopy as mentioned in this paper.
Abstract: The electrical properties of Ni0.27Cu0.10Zn0.63Fe2O4 (NCZF) prepared from auto combustion synthesis of ferrite powders have been studied by impedance and modulus spectroscopy. We studied frequency and temperature dependencies of impedance and electric modulus of NCZF in a wide frequency range (20 Hz-5 MHz) at different measuring temperatures SM T (30-225 ℃). The complex impedance spectra clearly showed both grain and grain boundary effects on the electrical properties. The observed impedance spectra indicated that the magnitude of grain boundary resistance gb R becomes more prominent compared to grain resistance b R at room temperature, and with the increase in SM T , gb R decreases faster than the intrinsic b R. The frequency response of the imaginary part of impedance showed relaxation behavior at every SM T , and the relaxation frequency variation with SM T appeared to be of Arrhenius nature and the activation energy has been estimated to be 0.37 eV. A complex modulus spectrum was used to understand the mechanism of the electrical transport process, which indicated that a non-Debye type of conductivity relaxation characterizes this material.
112 citations
TL;DR: In this paper, the exp(− Φ ( ξ ))-expansion method has been successfully implemented to seek traveling wave solutions of the coupled Higgs field equation and the Maccari system.
96 citations
TL;DR: In this article, the authors aimed to evaluate the potentiality of RWH systems in the South Agrabad in Chittagong city with an average annual precipitation of 3000mm, experiencing both water scarcity and urban flooding in the same year.
61 citations
TL;DR: Aqueous-phase reforming of glycerol was investigated over a series of Ni and Cu-Ni bimetallic catalysts supported on multiwalled carbon nanotubes (MWNT) in this paper.
47 citations
TL;DR: In this paper, a 3D discrete element method (DEM) analysis was carried out to examine the response of buried pipeline owing to fault movement, where 1.8 million spherical particles, which were considered to represent soil and a hollow circular pipe, were placed at a shallow depth in the proposed numerical model.
41 citations
01 Nov 2015
TL;DR: An Android based application that detects an accidental situation and sends emergency alert message to the nearest police station and health care center and is integrated with an external pressure sensor to extract the outward force of the vehicle body.
Abstract: Vehicle accident is the paramount thread for the people's life which causes a serious wound or even dead. The automotive companies have made lots of progress in alleviating this thread, but still the probability of detrimental effect due to an accident is not reduced. Infringement of spFieed is one of the elementary reasons for a vehicle accident. Therewithal, external pressure and change of tilt angle with road surface blameworthy for this mishap. As soon as the emergency service could divulge about an accident, the more the effect would be mitigated. For this purpose, we developed an Android based application that detects an accidental situation and sends emergency alert message to the nearest police station and health care center. This application is integrated with an external pressure sensor to extract the outward force of the vehicle body. It measures speed and change of tilt angle with GPS and accelerometer sensors respectively on Android phone. By checking conditions, this application also capable of reducing the rate of false alarm.
39 citations
TL;DR: In this article, two laboratory scale digesters were constructed to digest cow dung, where one set-up was used for digestion of cow Dung without catalyst and the other set up was used to digest Dung with catalyst.
39 citations
TL;DR: In this article, the exact traveling wave solutions to the (3+1)-dimensional mKdV-ZK equation and the (2+ 1)-dimensional Burgers equation are studied using the exp ( - Φ ( η ) -expansion method.
Abstract: In this work, the exact traveling wave solutions to the (3+1)-dimensional mKdV–ZK equation and the (2+1)-dimensional Burgers equation are studied using the exp ( - Φ ( η ) ) -expansion method. The traveling wave solutions are expressed in terms of the exponential functions, the hyperbolic functions, the trigonometric functions and the rational functions. This method is one of the powerful methods that appear in recent time in establishing some new exact traveling wave solutions to the nonlinear partial differential equations. It is shown that the exp ( - Φ ( η ) ) -expansion method is simple and valuable mathematical instrument for solving nonlinear evolution equations in mathematical physics and engineering.
36 citations
21 May 2015
TL;DR: A new technique that detects traffic density according to the area of the edges of vehicles for controlling traffic congestion is developed using image processing for intelligent traffic control system of Bangladesh.
Abstract: Traffic congestion is a daily occurrence in most urban areas of Bangladesh now a day. In the last 10 years the scenario has worsen due to rapid increase of vehicles and insufficient roads to accommodate them. This paper describes a method of real time area based traffic density estimation using image processing for intelligent traffic control system. Area occupied by the edges of vehicles will be considered to estimate vehicles density. Calculating the areas of different live roads, the system will automatically estimate the traffic density of each road which will help to determine the duration of each traffic light. An intelligent traffic signal control system with the proposed traffic density estimation technique will be far better than the conventional timer based system of Bangladesh. The main contribution of this research lies in the development of a new technique that detects traffic density according to the area of the edges of vehicles for controlling traffic congestion. Specialized algorithm, morphology and images captured with cameras will be used for the detection of traffic density for the intelligent traffic control system.
31 citations
TL;DR: In this article, the Korteweg-de Vries (KdV) equation is derived by using the well known reductive perturbation method, which admits the soliton like solitary wave solution.
Abstract: This work investigates the theoretical and numerical studies on nonlinear propagation of ion acoustic solitary waves (IASWs) in an unmagnetized plasma consisting of nonextensive electrons, Boltzmann positrons and relativistic thermal ions. The Korteweg-de Vries (KdV) equation is derived by using the well known reductive perturbation method. This equation admits the soliton like solitary wave solution. The effects of phase velocity, amplitude of soliton, width of soliton and electrostatic nonlinear propagation of weakly relativistic ion-acoustic solitary waves have been discussed with graphical representation found in the variation of the plasma parameters. The obtained results can be helpful in understanding the features of small but finite amplitude localized relativistic ion-acoustic waves for an unmagnetized three component plasma system in astrophysical compact objects.
TL;DR: Based on the proposed new exponential expansion method, the authors obtained the multiple explicit and exact traveling wave solutions of the strain wave equation for describing different types of wave propagation in microstructured solids.
TL;DR: In this paper, an alternative way of releasing heat of building is investigated in order to reduce energy demand of building built in tropical environment, where underground soil is considered as a source for extracting heat from building through thermal conductivity pipes.
Abstract: In this paper, an alternative way of releasing heat of building is investigated in order to reduce energy demand of building built in tropical environment. Underground soil is considered as a source for extracting heat from building through thermal conductivity pipes. Thermal conductivity pipes are con- sidered to be fixed on the inner faces of the walls and their lower part to be inserted to the ground where temperature is lower than the indoor temperature. The entire analyses were done numerically using ANSYS 11. Heat flow between two systems was studied and the performance of the thermal conductivity pipes was examined. The room temperature in the presence of thermal conductivity pipes as well as mechanical cooling system and other passive energy-efficient techniques of building were also studied. The underground soil was demonstrated to act as a heat sink and absorb heat released from the rooms and the thermal conductivity pipes would play a role in transferring heat from the rooms to the underground soil. The system works efficiently when it is used with other mechanical or passive cooling systems. In this way, energy saving measure could be possible to reduce building temperatures by around 3 � C.
TL;DR: In this article, the authors investigated Vickers hardness and the thermodynamic properties of the recently discovered nanolaminate carbide Ti 3 SnC 2 polymorphs using the first-principles calculations.
Abstract: We have investigated Vickers hardness and the thermodynamic properties of the recently discovered nanolaminate carbide Ti 3 SnC 2 polymorphs using the first-principles calculations. The chemical bonding shows a combination of covalent, ionic and metallic types. The strong covalent bonding is mainly responsible for high Vickers hardness of Ti 3 SnC 2 polymorphs. Thermodynamic properties are studied using the quasi-harmonic Debye model. The variation of bulk modulus, thermal expansion coefficient, specific heats, and Debye temperature with applied pressure ( P ) and temperature ( T ) are investigated systematically within the ranges of 0 - 50 GPa and 0 - 1000 K. The calculated results have been compared with available experimental and theoretical data.
01 Dec 2015
TL;DR: A multiuser password-protected SMS-based system fabricated with an LCD to provide information in an innovative and smart way and designed with simple logic with a robust algorithm to ensure efficiency and reliability with less cost.
Abstract: This paper elucidates a wireless digital noticing system to provide information in an innovative and smart way The proposed notice board is a multiuser password-protected SMS-based system fabricated with an LCD The communication and information transfer between the authentic user and the LCD display unit is done via GSM to ensure remote display facilities, so any notice can be displayed on the electronic board from the user's mobile SMS from distant places To ensure system flexibility, a multiuser noticing and displaying system has been implemented in the system which can display several notices simultaneously In addition, the user also can print any notice which is of concern to them The total system is designed with simple logic with a robust algorithm and fabricated with a PIC midrange microcontroller, LCD, GSM module and other commercially available electronic devices to ensure efficiency and reliability with less cost
09 Nov 2015
TL;DR: In this paper, a numerical analysis has been performed utilizing AMPS (Analysis of Microelectronic and Photonic Structures) simulator to examine the cell performances (V oc, J sc, FF and conversion efficiency) of ultra-thin CdTe solar cell.
Abstract: The polycrystalline ultra-thin cadmium telluride (CdTe) is familiar as the potential solar cell material for its higher efficiency, cost-effective, cell stability and clean generation of solar electricity. In this study, a numerical analysis has been performed utilizing AMPS (Analysis of Microelectronic and Photonic Structures) simulator to examine the cell performances (V oc , J sc , FF and conversion efficiency) of ultra-thin CdTe solar cell. During the research, reduction of CdTe layer was done in the proposed cell and found that 1µm absorber layer is enough for acceptable range for cell conversion efficiency. The possibility of this ultra-thin CdTe absorber layer was examined, as one with 100 nm ZnTe back surface field (BSF) layer to minimize the recombination losses at the back contact and to reduce the barrier height in the valence band of the proposed cell. Higher conversion efficiency of 22.53% (J sc = 24.28 mA/cm2, FF = 0.875, V oc = 1.06 V) has been achieved with only 0.8 µm of CdTe absorber layer along with 100 nm ZnTe BSF where as conversion efficiency is 18.68% (J sc = 21.47 mA/cm2, FF = 0.85, V oc = 1.02 V) without BSF layer. Moreover, the proposed CdTe solar cell showed better stability as the normalized efficiency of the proposed cell linearly decreased with the increasing operating temperature at the gradient of −0.16%/°C.
TL;DR: The (1+1)-dimensional nonlinear Klein-Gordon-Zakharov equation is considered as a model equation for describing the interaction of the Langmuir wave and the ion acoustic wave in high frequency plasma.
01 Dec 2015
TL;DR: In this article, an ultra-thin polycrystalline Cadmium Telluride (CdTe) solar cell was proposed to reduce barrier height in the valence band and to minimize the recombination losses at the back contact of the CdTe PV cell.
Abstract: Polycrystalline Cadmium Telluride (CdTe) is one of the leading solar cell materials for its efficiency, cost-effective and thermal stability. In this research work, numerical analysis is done by AMPS (Analysis of Microelectronic and Photonic Structures) simulator to investigate the cell performances (Jsc, FF, Voc, efficiency and temperature stability) of ultra-thin CdTe solar cell. Reduction of absorber layer was done and observed that 1 μm absorber layer is enough for acceptable range of cell conversion efficiency in the proposed cell. The possibility of this ultra-thin CdTe absorber layer was investigated, together with 100 nm SnTe back surface field (BSF) layer to reduce the barrier height in the valence band and to minimize the recombination losses at the back contact of the CdTe PV cell. From the investigation, it was found that the proposed ultra-thin cell have conversion efficiency of 18.68% (Jsc = 21.47 mA/cm2, FF = 0.85, Voc = 1.02 V) without BSF and with 100 nm SnTe BSF conversion efficiency increased to 22.61% (Jsc = 24.27 mA/cm2, FF = 0.876, Voc = 1.06 V) with only 0.7 μm of CdTe absorber layer. Moreover, without BSF and with SnTe BSF, the normalized efficiency of the proposed cell was linearly decreased with the increasing operating temperature at the gradient of −0.18%/°C and −0.16%/°C found in this analysis respectively, which indicated better stability of the proposed CdTe solar cell.
TL;DR: In this article, the steady two-dimensional laminar incompressible flow over a sphere in the presence of viscous dissipation and heat generation is considered, and the governing equations are solved numerically by numerical solution strategy as per requirement and suitability.
09 Nov 2015
TL;DR: A system of CPU power consumption reduction which supports Dynamic Voltage and Frequency Scaling (DVFS) and User Driven Frequency Scaled (UDFS) at the same time and it reduces 25% power consumption compared to default DVFS and 3% than existing UDFS technique.
Abstract: Despite the growing popularity of smartphones, it's extensive power consumption is still now a burning issue. In this regard, we propose and evaluate a system of CPU power consumption reduction which supports Dynamic Voltage and Frequency Scaling (DVFS) and User Driven Frequency Scaling (UDFS) at the same time. At first, a DVFS is used to scale the frequency level continuously based on loads present at that time. Then a UDFS is used to consider user satisfaction. Starting from the highest frequency level, UDFS gradually reduces the frequency level until users feel discomfort. The proposed technique calculates an optimum frequency as the starting frequency and then reduces that frequency until user shows discomfort. When CPU reaches in ideal state, processor frequency goes to the lowest level to save battery life. Our proposed technique is implemented in Samsung Galaxy S2 and it reduces 25% power consumption compared to default DVFS and 3% than existing UDFS technique.
TL;DR: In this paper, the influence of Al substitution on structural and electromagnetic properties of Ni 0.27 Cu 0.10 Zn 0.63 Al x Fe 2 − x O 4 was investigated.
21 May 2015
TL;DR: A system for integrating the citizen and authority in a common platform and work in together to make the Dhaka city healthier is constructed.
Abstract: The heart of a city depends on its purification of air, cleanliness of the roads and highways and overall it's surrounding environment. But if the condition disrupted, then the people live in the city have to pay for this. Different kinds of diseases spread out in an epidemic form and it is becoming tougher to lead a healthy life. However, people can ignore this condition by raising their hand to build up a healthy city. So we constructed a system for integrating the citizen and authority in a common platform and work in together to make the Dhaka city healthier. The system is an android based application where the user himself can contribute to clean his city, notify volunteer to come forward or can inform city corporation. The amenities of this application are - it ameliorates the user to detect nearby dustbins location with path, helps to see available volunteer on the map, notify them using google push service notification and assists them to submit a report to authorities if a problem arise.
TL;DR: In this article, the impact of the flow parameters on the velocity, temperature, and concentration are computed, discussed and have been graphically represented in figures and also the shearing stress, and rate of concentration shown in table 1 for various values of different parameters.
01 Dec 2015
TL;DR: A self-adjusting pixel to combine linear and logarithmic response maintaining high fill factor is proposed for dynamic range imager and simulated in Cadence Virtuoso in 180nm technology node and analyzed for comparative study of dynamic range.
Abstract: Due to low cost, low power consumption and better on-chip functionality CMOS Image Sensor has become the main image sensor for consumer electronics, machine vision as well as in research applications. Besides the advantages, a CMOS image sensor suffers from noises, less sensitivity as well as lacks of Dynamic Range (DR). Logarithmic response Active Pixel Sensor (APS) is a solution for wide dynamic range imager maintaining high fill factor. 3T Linear APS (Active Pixel Sensor) has better performance in low illumination, but very poor sensitivity in low illumination. For 3T logarithmic APS has satisfactory performance in high illumination, but limited sensitivity in low illumination. Few reported to implement both linear and logarithmic capture for a single frame which increases the capture time. Implementation of in-pixel circuitry to combine both linear and logarithmic in a single capture which decreases the fill factor of the pixel is also reported. In this paper, we propose a self-adjusting pixel to combine linear and logarithmic response maintaining high fill factor. The proposed pixel was simulated in Cadence Virtuoso in 180nm technology node and analyzed for comparative study of dynamic range.
TL;DR: In this article, a finite element based model of the heat transfer problem is presented for an 800mm long pipe with 26mm inner diameter and 5mm thickness, and simulations have been completed for both stationary and time dependent conditions with Reynolds number 1600∼2400.
TL;DR: This brief presents a parallel single-rail self-timed adder based on a recursive formulation for performing multibit binary addition that attains logarithmic performance over random operand conditions without any special speedup circuitry or look-ahead schema.
Abstract: This brief presents a parallel single-rail self-timed adder. It is based on a recursive formulation for performing multibit binary addition. The operation is parallel for those bits that do not need any carry chain propagation. Thus, the design attains logarithmic performance over random operand conditions without any special speedup circuitry or look-ahead schema. A practical implementation is provided along with a completion detection unit. The implementation is regular and does not have any practical limitations of high fanouts. A high fan-in gate is required though but this is unavoidable for asynchronous logic and is managed by connecting the transistors in parallel. Simulations have been performed using an industry standard toolkit that verify the practicality and superiority of the proposed approach over existing asynchronous adders.
TL;DR: In this article, a landslide susceptibility index map has been prepared using analytical hierarchy process (AHP) model based on geographic information system (GIS) and remote sensing (RS) and its susceptibility is analyzed through community vulnerability assessment tool (CVAT).
Abstract: In Chittagong city, landslide phenomena is the most burning issue which causes great problems to the life and properties and it is increasing day by day and becoming one of the main problems of city life. On 11 June 2007, a massive landslide happened in Chittagong City Corporation (CCC) area, a large number of foothill settlements and slums were demolished; more than 90 people died and huge resource destruction took place. It is therefore essential to analyze the landslide susceptibility for CCC area to prepare mitigation strategies as well as assessing the impacts of climate change. To assess community susceptibility of landslide hazard, a landslide susceptibility index map has been prepared using analytical hierarchy process (AHP) model based on geographic information system (GIS) and remote sensing (RS) and its susceptibility is analyzed through community vulnerability assessment tool (CVAT). The major findings of the research are 27% of total CCC area which is susceptible to landslide hazard and whereas 6.5 sq.km areas are found very highly susceptible. The landslide susceptible areas of CCC have also been analyzed in respect of physical, social, economic, environmental and critical facilities and it is found that the overall CCC area is highly susceptible to landslide hazard. So the findings of the research can be utilized to prioritize risk mitigation investments, measures to strengthen the emergency preparedness and response mechanisms for reducing the losses and damages due to future landslide events. DOI: http://dx.doi.org/10.3126/ije.v4i2.12635 International Journal of Environment Vol.4(2) 2015: 157-181
01 Nov 2015
TL;DR: In this article, a framework has been proposed for detection of the road sign from road images, two natural properties of a Bangladeshi road sign are utilized, they are - border color rim of road sign and the shape of a road sign.
Abstract: Detection of road sign from a road image is very crucial for intelligent transportation system for awareness of drivers and blind pedestrians. In this regard, a framework has been proposed in this paper for detection of the road sign from road images. For detection of the road sign, two natural properties of a Bangladeshi road sign is utilized, they are - border color rim of the road sign and the shape of the road sign. Based on these ideas initially, YCbCr color model is used to eliminate the illumination sensitiveness for segmentation. In the second step, statistical threshold value is used for color segmentation. Next, labeling and filtering is used to extract the shapes. Finally, Distance to Borders (DtBs) vector is used to verify the region of interest (ROI) for detecting the Bangladeshi road sign (BRS). Various road images are used with a variety of conditions to test the proposed framework and results are presented to prove its efficiency.
01 Feb 2015
TL;DR: The proposed design algorithm of FIR and IIR is modeled in HDL and after the logically verified synthesize in the XST synthesis tool, which can be used to implement the logical function because of its cost-effective properties.
Abstract: At the modern world digital signal processing (DSP) has turned into an enormously vital subject. A fundamental aspect of the digital signal processing is filtering. Filtering is a selective system which passes a certain range of frequency and attenuating the others frequency. Digital filtering is a powerful sector of DSP related works. A digital filter is a system which performs mathematical operations on a sampled or discrete time variant signal to shrink or enhance assured aspects of that signal. Digital filters are classified into finite impulse response (FIR) and infinite impulse response (IIR), which are based on the duration of the impulse response. FIR is a stable system and there is no feedback, but IIR has a feed forward path. This paper mainly focuses on the design of FIR and IIR filters of different forms like direct form or transposed of direct form in FPGA. FPGA is a system which can be used to implement the logical function because of its cost-effective properties. The proposed design algorithm of FIR and IIR is modeled in HDL and after the logically verified synthesize in the XST synthesis tool. The design performance of FIR and IIR is analyzed through the timing diagrams summary (time delay, minimum execution period etc.), HDL synthesis report and device utilization summary.
21 May 2015
TL;DR: Experimental results show that the proposed method to detect moving object's cast shadow and then remove the shadow region from Video frames is easy to be understood, can detect and remove theshadow and extract the moving object properly.
Abstract: Shadow area causes false detection of moving objects during segmentation and tracking those objects properly. Shadows are also reason for the texture loss of background and false connectivity of independent blobs. Hence, we propose a simple method to detect moving object's cast shadow and then remove the shadow region from Video frames. We extract the moving object by subtraction algorithm based on the difference of pixels. Texture, variance property and intensity in HSV color space are used to detect the shadow region and shadow removal is based on the information from the reference frame. Background information is initially stored in reference frame. The next incoming frames with object are compared with this frame. Color information for both background subtraction and shadow detection to improve object segmentation are ensured in this paper. Experimental results show that our proposed method is easy to be understood, can detect and remove the shadow and extract the moving object properly.