Showing papers by "Chittagong University of Engineering & Technology published in 2016"

Evaluating plastic shrinkage and permeability of polypropylene fiber reinforced concrete

Abstract: Plastic concrete is susceptible to develop cracks due to shrinkage in dry and windy conditions. Addition of fibers could reduce propagation of this crack. On the other hand, permeability determines the durability properties of concrete. This study evaluated strength, plastic shrinkage and permeability (gas and water) of concrete incorporating ‘polypropylene’ fiber (aspect ratio 300) in various proportions (viz. 0.10%, 0.15%, 0.2%, 0.25% and 0.3%) by volume of concrete. Plane concrete samples were also prepared and tested for reference purpose. Inclusion of 0.1% fiber gave minor reduction (2%) in compressive strength while the tensile strength increased by 39% with same fiber content compared to the plain concrete. A significant reduction in crack generation, appearance period of first crack and crack area between plane concrete and fiber reinforced concretes was found. The experimental result with inclusion of 0.1–0.3% fiber in concrete indicated that plastic shrinkage cracks were reduced by 50–99% compared to the plain concrete. For reference concrete (without fiber), test within the high temperature and controlled humidity chamber gave higher crack width than the acceptable limit (3 mm) specified by the ACI 224. With the inclusion of 0.1% fiber reduced the crack width down to 1 mm and the trend was continued with the addition of more fibers. However, results showed that with the addition of polypropylene fiber both water and gas permeability coefficient was increased. Therefore, it is concluded that the fiber reinforced concrete would work better for plastic shrinkage susceptible structural elements (flat elements such as slab); however, it requires careful judgement while applying to a water retaining structures.

An environment-friendly solution for indoor air purification by using renewable photocatalysts in concrete: A review

Abstract: Photocatalyst is needed for cleaner environment and a better quality of life. This fact leads an idea of more eco-compatible use of light. This approach could become an integral component of strategies to reduce indoor air pollutants through the use of photocatalysts as construction materials. In this study, we discuss the quality of indoor air, sources of pollutants in the indoor environment, and the photocatalysis process. Moreover, the different parameters and uses of different photocatalysts in concrete for indoor air purification, starting from the early research until the current research, are described, and the reaction mechanism of photocatalytic oxidation and sustainable construction by using photocatalysts are also reviewed.

IoT based autonomous percipient irrigation system using raspberry Pi

Abstract: This paper propounds a design for automatic water supplying system in farmland using raspberry pi 3, Arduino microcontrollers, WiFi module, GSM shield, relay boards and couple of sensors. The components we used in our system ensures overall fecund, scalable and spirited implementation. Depending upon the moisture level of farmland and daylight intensity, the system can detect the appropriate time of water supply in the trees and can also keep track of the water level to prevent water from being accumulated around the roots of the saplings. The analog data received from the sensors are transmitted by Arduino as digital signal via Wifi Module to the Raspberry Pi 3. The system is able to notify the administrator if water shortage arises in the main water supply and an administrator can also communicate with the system by sending SMS (Short message service) of a particular keyword. This system can be applied in farmland as well as small pot plants. Using this system, a very promising outcome is found in sustaining and cherishing the plants in a more scientific way.

License plate detection and character recognition system for commercial vehicles based on morphological approach and template matching

Abstract: Though license plate detection and recognition system has a lot of applications but a very little work has been done on Bangla license plate recognition. Variations among the license plate patterns and complex background of Bangladeshi license plates make it more difficult to use the existing algorithms. Because of this, we propose a solution for Bangla license plate detection and recognition. Firstly, the position of the vehicle is determined. In our country, commercial License Plates have the unique color (green) of its own. That's why; we select the portions of green color with the matching RGB intensity of the plate. A boundary based contour algorithm, area and aspect ratio have been proposed to track down the license plate in the vehicle region. License plate rows containing registration information have been separated by using horizontal projection with threshold. The characters and the digits of the rows have been segmented using vertical projection with threshold value. Finally, template matching has been used for recognizing the characters and the digits of the Bangla license plate. We tested our algorithms for over 180 still images captured from the road. We achieve93% success in license plate detection, 98.1% success in segmentation and 88.8% success rate in Bangla license plate recognition.

An ab initio investigation of vibrational, thermodynamic, and optical properties of Sc 2 AlC MAX compound

Abstract: The structural vibrational, thermodynamical, and optical properties of potentially technologically important, weakly coupled MAX compound, Sc2AlC are calculated using density functional theory (DFT). The structural properties of Sc2AlC are compared with the results reported earlier. The vibrational, thermodynamical, and optical properties are theoretically estimated for the first time. The phonon dispersion curve is calculated and the dynamical stability of this compound is investigated. The optical and acoustic modes are observed clearly. We calculate the Helmholtz free energy (F), internal energy (E), entropy (S), and specific heat capacity (Cv ) from the phonon density of states. Various optical parameters are also calculated. The reflectance spectrum shows that this compound has the potential to be used as an efficient solar reflector.

Ion acoustic solitary waves in plasmas with nonextensive distributed electrons, positrons and relativistic thermal ions

Abstract: The theoretical and numerical studies have been investigated on nonlinear propagation of weakly relativistic ion acoustic solitary waves in an unmagnetized plasma system consisting of nonextensive electrons, positrons and relativistic thermal ions. To study the characteristics of nonlinear propagation of the three-component plasma system, the reductive perturbation technique has been applied to derive the Korteweg–de Vries equation, which divulges the soliton-like solitary wave solution. The ansatz method is employed to carry out the integration of this equation. The effects of nonextensive electrons, positrons and relativistic thermal ions on phase velocity, amplitude and width of soliton and electrostatic nonlinear propagation of weakly relativistic ion acoustic solitary waves have been discussed taking different plasma parameters into consideration. The obtained results can be useful in understanding the features of small amplitude localized relativistic ion acoustic solitary waves in an unmagnetized three-component plasma system for hard thermal photon production with relativistic heavy ions collision in quark–gluon plasma as well as for astrophysical plasmas.

Exact solutions to the (3+1)-dimensional coupled Klein–Gordon–Zakharov equation using exp(−Φ(ξ))-expansion method

Abstract: In this article, the exp ( - Φ ( ξ ) ) -expansion method is modified for (3+1)-dimensional space–time coordinate system and successfully implemented to construct the new exact traveling wave solutions of the (3+1)-dimensional coupled Klein–Gordon–Zakharov equation. The solutions of this equation are expressed in terms of hyperbolic, trigonometric, exponential and rational functions. The results illustrate its effectiveness for solving nonlinear coupled partial differential equations arises in mathematical physics and engineering. The annihilation phenomena of the wave propagation in the x – y plane are also investigated. Furthermore, the three-dimensional surface plots due to the obtained solutions are also given to make the dynamics of the equation visible.

A surveillance system based on motion detection and motion estimation using optical flow

Abstract: In today's world Surveillance system is playing an important role in the field of security. Moving object detection has been widely used in video surveillance system. As well as motion estimation is an important part of surveillance video processing such as video filtering and compression from video frames. This paper proposes a simple and efficient surveillance system based on motion detection with motion vector estimation from surveillance video frames. Motion is detected with a new approach-edge region determination which makes detection faster. The surveillance video is then processed for motion estimation using optical flow with Horn-Schunck algorithm for estimating motion vector for its reasonable performance and simplicity. This method is computationally faster without requiring any special hardware for image processing. So it can be more applicable to embedded systems.

Machine-to-machine communication based smart home security system by NFC, fingerprint, and PIR sensor with mobile android application

Abstract: The rapid growth of burglary and theft over the last few years has been threatening to the vulnerability of traditional home security systems. In this research, this hazardous circumstance persuades the authors to develop a machine-to-machine (M2M) communication based smart home security system. Here a multi-layer home security system (HSS) has been developed which maintains six levels of security and necessary control responses against unwanted burglars and intruders. As a part of this development, the first security level uses Near Field Communication (NFC) tag, the second level uses a secured password system and the third level uses fingerprint authentication. After that, a GSM module embedded with the proposed HSS sends the logged password to a remote server via M2M communication. The server encrypts the password and noties the homeowner via an android based mobile application whether the person is an authenticated person or not. In the final stage of security, if an intruder wants to enter the room by breaking the password without NFC tag and fingerprint encryption, a Passive Infrared (PIR) motion sensor will work and sounds a buzzer for alarm. Therefore, the automatic and embedded operation of the proposed HSS makes it more secure, reliable and robust than other traditional systems.

New analytical solutions for propagation of small but finite amplitude ion-acoustic waves in a dense plasma

Abstract: The theoretical and numerical studies have been investigated on the nonlinear propagation of electrostatic ion-acoustic waves (IAWs) in an un-magnetized Thomas–Fermi plasma system consisting of electron, positrons, and positive ions for both of ultra-relativistic and non-relativistic degenerate electrons. Korteweg-de Vries (K-dV) equation is derived from the model equations by using the well-known reductive perturbation method. This equation is solved by employing the generalized Riccati equation mapping method. The hyperbolic functions type solutions to the K-dV equation are only considered for describing the effect of plasma parameters on the propagation of electrostatic IAWs for both of ultra-relativistic and non-relativistic degenerate electrons. The obtained results may be helpful in proper understanding the features of small but finite amplitude localized IAWs in degenerate plasmas and provide the mathematical foundation in plasma physics.

Complex impedance and electric modulus studies of Al substituted Co0.4Cu0.2Zn0.4AlxFe2-xO4 ferrites prepared by auto combustion technique

Abstract: Al substituted Co0.4Cu0.2Zn0.4AlxFe2-xO4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) ferrites have been prepared using auto combustion route. X-ray diffraction studies revealed the formation of single phase spinel type cubical structure. The dielectric properties of the samples at room temperature have been studied over the frequency range of 20 Hz to 15 MHz. The dielectric constant and loss tangent is found to decrease with increasing Al content. Dielectric spectra analysis and modulus show the non-Debye type behavior in the material. Complex impedance spectra of the samples have been analyzed and explained using the Cole-Cole expression. The complex impedance data are indicative of the dominance of grain boundary resistance. AC conductivity has a trend to decrease with Al content and a shift of hopping frequency towards lower frequency is also observed.

Oblique propagation of ion acoustic shock waves in weakly and highly relativistic plasmas with nonthermal electrons and positrons

Abstract: This work investigates the oblique nonlinear propagation of ion acoustic (IA) shock waves for both weakly and highly relativistic plasmas composed of nonthermal electrons and positrons with relativistic thermal ions. The KdVB-like equation, involving dispersive, weakly transverse dispersive, nonlinearity and dissipative coefficients, is derived employing the well known reductive perturbation method. The integration of this equation is carried out by the $\mathit{tanh}$ method taking the stable shock formation condition into account. The effects of nonthermal electrons and positrons, nonthermal electrons with isothermal positrons, isothermal electrons with nonthermal positrons, and isothermal electrons and positrons on oblique propagation of IA shock waves in weakly relativistic regime are described. Furthermore, the effects of plasma parameters on oblique propagation of IA shock waves in highly relativistic regime are discussed and compared with weakly relativistic case. It is seen that the plasma parameters within certain limits significantly modify the structures of the IA shock waves in both cases. The results may be useful for better understanding of the interactions of charged particles with extra-galactic jets as well as astrophysical compact objects.

Highly efficient maximum power point tracking using DC–DC coupled inductor single-ended primary inductance converter for photovoltaic power systems

Abstract: Solar photovoltaics (PVs) have nonlinear voltage–current characteristics, with a distinct maximum power point (MPP) depending on factors such as solar irradiance and operating temperature. To extract maximum power from the PV array at any environmental condition, DC–DC converters are usually used as MPP trackers. This paper presents the performance analysis of a coupled inductor single-ended primary inductance converter for maximum power point tracking (MPPT) in a PV system. A detailed model of the system has been designed and developed in MATLAB/Simulink. The performance evaluation has been conducted on the basis of stability, current ripple reduction and efficiency at different operating conditions. Simulation results show considerable ripple reduction in the input and output currents of the converter. Both the MPPT and converter efficiencies are significantly improved. The obtained simulation results validate the effectiveness and suitability of the converter model in MPPT and show reasonable agreement...

Structural, elastic, electronic and optical properties of Cu3MTe4 (M = Nb, Ta) sulvanites — An ab initio study

Abstract: The elastic, electronic, and optical properties of Cu3MTe4 (M = Nb, Ta) are investigated for the first time using the density-functional formalism. The optimized crystal structure is obtained and the lattice parameters are compared with available experimental data. Different elastic moduli are calculated. The Born criteria for mechanicalstability are found to be fulfilled from the estimated values of the elastic moduli, Cij . The band structure and the electronic energy density of states (EDOS) are also determined. The band structure calculations show semiconducting behavior for both the compounds. The theoretically calculated values of the band gaps are found to be strongly dependent on the nature of the functional representing the exchange correlations. Technologically significant optical parameters (e.g., dielectric function, refractive index, absorption coefficient, optical conductivity, reflectivity, and loss function) have been determined. Important conclusions are drawn based on the theoretical findings.

A machine learning based approach for the detection and recognition of Bangla sign language

Abstract: Speech impaired people are detached from the mainstream society due to the lacking of proper communication aid. Sign language is the primary means of communication for them which normal people do not understand. In order to facilitate the conversation conversion of sign language to audio is very necessary. This paper aims at conversion of sign language to speech so that disabled people have their own voice to communicate with the general people. In this paper, Hand Gesture recognition is performed using HOG (Histogram of Oriented Gradients) for extraction of features from the gesture image and SVM (Support Vector Machine) as classifier. Finally, predict the gesture image with output text. This output text is converted into audible sound using TTS (Text to Speech) converter.

Design and implementation of smart attendance management system using multiple step authentication

Abstract: In the traditional attendance system of Bangladesh, the teachers either call the name or identity number of the students to which the students respond or pass the attendance sheet to the students to sign. With the increase of the number of students in the last two decades, the difficulties in attendance management system has increased remarkably. Again, in case of passing attendance sheet to the students, some students sign multiple times and proxy attendance is taken. These two systems are very time consuming. To overcome these inconveniencies, this paper represents a smart attendance system prototype. In this paper radio frequency identification, biometric fingerprint sensor and password based technologies are integrated to develop a cost effective, reliable attendance management system. A desktop application is developed in C# environment to monitor the attendance system.

A smartphone based application to improve the health care system of Bangladesh

Abstract: Nowadays, smartphones have reached every hand and every home. As a result, people are making use of the beneficial mobile applications to make their everyday life easier. This paper focuses on development of a mobile application(app) to help providing an effective health care system. Using this app people can get numerous benefits like finding hospital information in the city, information about cabin, cabin booking with payment, intelligent suggestion on choosing suitable hospital, finding a doctor, emergency service calling, first aid information, alarm system for medication, Body Mass Index(BMI) calculator etc. This application will be a helping hand for people who find it difficult to select hospital, book cabin, contacting doctor for appointment or seeking help in emergency situation. Besides, it will help the masses in their everyday life by providing health care information, aid and medication information, medicine reminder system, etc.

First-principles study of SnO under high pressure

Abstract: This paper reports the first-principles study of SnO under high pressure within the generalized gradient approximation (GGA). We have calculated the structural, elastic, electronic and optical properties of SnO. The elastic properties such as the elastic constants Cij, bulk modulus, shear modulus, Young’s modulus, anisotropic factor, Pugh’s ratio and Poisson’s ratio are calculated and analyzed. Mechanical stability of SnO at all pressures is confirmed using the Born’s stability conditions in terms of Cij. It is also found that SnO exhibits very high anisotropy. The energy band structure and density of states are also calculated and analyzed. The results show the semiconducting and metallic properties at zero and high pressures, respectively. Furthermore, the optical properties are also calculated. All the results are compared with those of SnO where available but most of the results at high pressure are not compared due to the unavailability of results.

Heat transfer performance evaluation and prediction of correlation for turbulent flow through a tube with helical tape inserts at higher Reynolds number

Abstract: An experimental investigation was accomplished to evaluate the performance of heat transfer for turbulent flow through a tube with helical tape inserts. The mild steel helical tape inserts with different twist ratios of 1.88, 3.13, 4.69, 6.41 and 7.81 were used in the flow field. Heat transfer and pressure drop data were prompted for a wide range of Reynolds number from 7200 to 50,000. The experimental results indicated that the Nusselt number, friction factor and thermal performance factor were increased with decreasing twist ratio. The results also showed that helical tape inserts of different geometries in a circular tube enhanced the heat transfer rate significantly with corresponding increase in friction factor. Nusselt number and friction factor for the tube with inserts were found to be increased up to 260 and 285 %, respectively, than those over the plain tube values at the comparable Reynolds number. The heat transfer performance was evaluated and found to be 44 % higher compared to the plain tube based on the constant blower power. Finally, new correlations were proposed for the twist ratios ranging from 1.88 to 7.81 for predicting the heat transfer, friction factor and thermal performance factor for turbulent flow through a circular tube fitted with helical tape inserts.

An evaluation of disaster risk reduction (DRR) approaches for coastal delta cities: a comparative analysis

Abstract: Deltas are the promising places with multifarious ecosystems and arable soils along with the ease of water transportation system; hence, a number of important cities are established in or near coastal delta regions. However, due to the geomorphic characteristics, those cities are extremely exposed to hydro-meteorological hazards, especially to riverine and coastal flood. Additionally, climate change, rapid urbanization and subsidence are exacerbating the existing situation and causing monumental loss. Researchers as well as various international organizations like United Nations Inter-Agency Secretariat of the International Strategy for Disaster Reduction have recognized the implications of formulating disaster risk reduction (DRR) plans for coastal delta cities. This demands for the excogitation of adaptation policies and measures in addition to the mitigation efforts to reduce flood risks. In this regard, to support the comprehensive concept development, this study elicits different components of flood risk reduction policies and measures, congenial for coastal delta cities in respect of physical and environmental perspectives. Eleven precedent (model) cities are selected to study their various initiatives for reducing coastal flood risks. Findings show that protecting cities from flooding and reducing exposure to floods are two different but interrelated approaches of DRR. Combinations of structural and non-structural measures are the prerequisites to achieve the goal of effective DRR.

High performance and stable molybdenum telluride PV cells with Indium Telluride BSF

Abstract: Molybdenum telluride (MoTe2) is a very promising candidate as PV cell for better cell stability and performance. In this research work, AMPS (Analysis of Microelectronic and Photonic Structures) simulator was used to examine the performance parameters (Jsc, Voc, FF and conversion efficiency) of ultra-thin MoTe2 PV cell through numerical analysis. During the study, it was found that absorber layer thickness of MoTe2 PV cell is adequate to achieve cell efficiency at satisfactory level. In addition, the hidden potentiality of MoTe2 PV cell was examined by inserting Indium Telluride (ImTe3) back surface field (BSF) between absorber layer and back contact metal. The conversion efficiency of 17.06% (FF = 0.730, Voc = 0.98 V and Jsc = 23.74 mA/cm2) has been achieved for 1 μm absorber layer of MoTe2 PV cell without BSF, whereas higher conversion efficiency is 25.29% (FF = 0.847, Voc = 1.08 V and Jsc = 27.60 mA/cm2) achieved at room temperature with only 0.7 μm of MoTe2 absorber layer along with 100 nm In2Te3 BSF. This research work compares the thermal stability of the structure of MoTe2 PV cell with and without BSF. It was found that the normalized efficiency decreased in response of increasing the operating temperature at the gradient of −0.0275%/°C without BSF. For the addition of In2Te3 BSF in the proposed MoTe2 PV cell, the degradation of normalized efficiency was too less in the range of higher operating temperature.

Traffic Sign Recognition using SURF: Speeded up robust feature descriptor and artificial neural network classifier

Abstract: Traffic Sign Recognition (TSR) system is a vital component of intelligent transport system. It plays an important role by enhancing the safety of the drivers, pedestrians and vehicles as traffic signs provide important information of the traffic environment of the road and assist the drivers to drive more safely and easily by guiding and warning. This paper represents road sign detection and recognition system based on speeded up robust feature (SURF) descriptor that is invariant to rotation, skew and occlusion of the sign and artificial neural network (ANN) classifier. The proposed system consists of three steps. In the first step the road scene image is segmented using color based thresholding algorithm followed by some post processing like morphological analysis and filtering using region properties to extract the road sign as a blob of region. Next, shape verification is carried out by using translation, scaling and rotation invariant features vector named Distance to Borders (DtBs) of the segmented blob. Finally the recognition of the traffic sign is implemented using ANN classifier with the training of SURF descriptor. The proposed system simulated on offline road scene images shows a high success rate in the recognition stage. The performance of the classifier is illustrated in terms of cross entropy, confusion matrix and receiver operating characteristic (ROC) curve.

Short paper: enhancing Wi-Fi security using a hybrid algorithm of blowfish and RC6

Abstract: Nowadays, Wi-Fi is a very popular Technology. Faster data transfer and Security both are very important for Wi-Fi. At present, Advanced Encryption Standard (AES) is used for Wi-Fi that is more secured than other encryption algorithms but it is not so fast because of it's complex functions. On the other hand, Blowfish is a very faster encryption algorithm but it cannot apply on Wi-Fi because of it's security problems. In this paper, a hybrid algorithm of Blowfish and Rivest Cipher 6 (RC6) is proposed that solves the security problems of Blowfish and also maintains the fastness of Blowfish and makes it able to use it in place of AES. It uses two innovative criteria. One is ingenious confusion process using two random numbers "a" and "w" that removes reflectively weak key attack and Known plaintext attack of Blowfish. The other is usage of one S-Box by overlapping process that eliminates the collision key attack of Blowfish. Sub key generation process of this algorithm also removes the Brute Force attack of AES. This paper tries to give an efficient algorithm that enhances the performance of Blowfish algorithm by adding a function of RC6 with it. The adding process is trickily handed here that makes the proposed algorithm as fast as Blowfish and also secured like existing AES. The proposed algorithm takes less encryption –decryption time like Blowfish and also secured like AES. Throughput, Average time for different data lengths and attack removal process are used to measure the efficiency of this proposed algorithm.

Crimecast: A crime prediction and strategy direction service

Abstract: Various researches on criminology provides us with a key piece of information about criminal psychology that, a criminal doesn't hover around unknown territory rather they commit crimes when opportunity provides in a concentrated or familiar area i.e. hotspots. So, a crime predicting model can be simulated using crime pattern theory which can analyze verified past crime data and predict future criminal activities. The aim of this paper is to introduce CRIMECAST which is a crime prediction and strategy direction service which attempts to predict probable future crimes by simulating probabilistic model implementation and Artificial Neural Network. CRIMECAST is a spatial crime analysis process that focuses on authentic crime history and predicts crime, develops strategy map, provides security alert. Our simulation on very big dataset show that CRIEMECAST outperforms all other methods of making crime predictions.

Application of the novel ( G ′/ G )-expansion method to construct traveling wave solutions to the positive Gardner-KP equation

Abstract: The novel (G′/G)-expansion method is one of the powerful methods accredited at the present time for establishing exact traveling wave solutions to nonlinear evolution equations (NLEEs). In this article, the method has been implemented to find the traveling wave solutions to the positive Gardner-KP equation. The efficiency of this method for finding exact and traveling wave solutions has been demonstrated. The obtained solutions have been compared with the solution obtained by other methods. The solutions have also been demonstrated by figures. It has been shown that the method is straightforward and an effective tool for solving NLEES that occur in applied mathematics, mathematical physics, and engineering.