Conference Paper

Permanent URI for this collectionhttps://hdl.handle.net/10361/6992

Browse

Now showing 1 - 6 of 6

Humidity sensor using surface adsorbed channel modulated Graphene nanoribbon: NEGF approach
(© 2014 Institute of Electrical and Electronics Engineers Inc., 2015-01) Shakil, Shifur Rahman; Zohra, Fatema Tuz; Pramanik, Parna; Tushar, Raihanul Islam; Department of Computer Science and Engineering
Electronic transport properties of Graphene nanoribbon (GNR) are explored by self-consistent numerical simulation. The effects of vapour (H2O) adsorption in GNR sheets on its current-voltage (I-V) characteristics, conductivity, electrostatic difference potential and device density of states were studied with necessary physical insight. We found that conductivity of GNR sheet increases in some particular energy range with the increase in number of H2O molecules adsorbed. Then we encounter the effects of metal-GNR contact to investigate the practical performance of GNR as a medium of humidity sensing. Later we propose a simple schematic model for GNR Humidity Sensor (GNRHS) to investigate its performance in applied regime.
Chondrobot-2: A simple and efficient semi-autonomous tele-robotic lunar excavator
(© 2012 IEEE, 2012) Rhaman, Md. Khalilur; Hossain, Md. Jonayet; Anik, Kazi Mohammad Razin; Oyon, Mahmudul Hasan; Nabia, Sarah Binte Nasir; Rahi, Nabil Shaker; Khan, Bonny Amin; Miran, Md. Mashiur Rahman; Bhuian, Belal Hossain; Rahman, Md. Mosaddequr; Department of Computer Science and Engineering
A simple, light-weight and efficient excavation system to excavate and collect lunar regolith has been developed at BRAC university. The excavation system has a dimension of 1.21m × 0.66m × 0.74m with a total weight of 65 kg. This four wheel drive robot consists of a bucket-ladder system for excavation and is capable of collecting 8kg of regolith per minutes. It also includes a collector bucket which can contain 18kg regolith and deposit in a bin which is installed on 50 cm height. The excavation hardware can be operated both manually and remotely through a web browser by logging in from any computer without direct visual and auditory access to the hardware. A KINECT sensor based semi-auto navigation is incorporated to avoid obstacle while motion.
A simple tele-robotic lunar excavator
(© 2012 IEEE, 2013) Rhaman, Md. Khalilur; Hasan, Shiblee Imtiaz; Hossain, Md. Jonayet; Anik, Kazi Mohammad Razin; Oyon, Mahmudul Hasan; Bhuian, Belal Hossain; Rahman, Md. Mosaddequr; Department of Computer Science and Engineering
An excavation tele-robotic system is developed to excavate and collect lunar regolith. The excavator has been developed by the team BRACU ChondroBot consisting students from BRAC University for NASA's 2nd Annual Lunabotics Mining Competition (LMC) 2011. Considering the requirement of NASA and calculating the load, friction and power the mechanical excavator was designed and built. The dimension of the excavator is 1.45m ×.74m × 1.48m and the weight is 80 kg. It consists of two excavation arm and one pulley system depositor bucket. Two conveyer belt type wheels are used to drive the robot. Efficient control and communication is always a big challenge for a Tele-robot. In our developed system hardware can be operated both manually and remotely through a web browser by logging in from any computer without direct visual and auditory access to the hardware. A unique control circuit, graphical user interface and communication module for two terminals are also developed for remote access.
Vibration and voice operated navigation system for visually impaired person
(IEEE Computer Society, 2014) Mahmud, Nasif; Saha, R. K.; Zafar, R. B.; Bhuian, Dr. Md. Belal Hossain; Sarwar, Shahzad S.; Department of Electrical and Electronic Engineering
Usually blind people use white canes which are very limited in its ability to provide navigation assistance to the user and cannot easily detect obstacles. Mobility of visually impaired people is limited by their inability to perceive their surroundings. Therefore the purpose of this project is to build a navigation system that will be able to guide a visually impaired person safely and with ease, in an indoor and outdoor environment. This goal has been realized through the use of an ultrasonic device to determine the range of obstacles and also a microcontroller to act accordingly. The system includes a warning system through voice rendering and through generation of vibration.
Transition in electronic transport properties of graphene nanoribbon due to the adsorption of atoms and molecules
(© 2015 Institute of Electrical and Electronics Engineers Inc., 2015) Shakil, Shifur Rahman; Saha, Atanu Kumar; Bhuian, Md. Belal Hossain; Department of Electrical and Electronic Engineering
The adsorption effects of gas molecules on semiconducting armchair graphene nanoribbon (A-GNR) are studied considering on the significant changes over current-voltage characteristics, device density of states and electrostatic difference potential. The orientation of gas molecules and adsorption sites play an important role on charge transfer between the graphene surface and the molecules. The charge transfer mechanism is discussed in the light of molecular orbital theory. We have used three gas molecules-CO2, NH3 and NO as adsorbates and chose such orientation that adsorbates can act only as donor. Finally, we have made a conclusion that semiconducting A-GNR shows metallic behaviour after adsorbing optimum number of adsorbates corresponding to the area of A-GNR. Such semiconducting to metal transition can be used as sensing parameters.
Vapor adsorption limitation of graphene nanoribbons in quasi conductance increment: a NEGF approach
(© 2015 Institute of Electrical and Electronics Engineers Inc., 2015) Shakil, Shifur Rahman; Zohra, Fatema Tuz; Pramanik, Parna; Tushar, Raihanul Islam; Saha, Atanu Kumar; Bhuian, Md Belal Hossain; Department of Electrical and Electronic Engineering
The adsorption of H2O molecules on Armchair Graphene Nanoribbons (A-GNR) was theoretically studied using Non Equilibrium Green Function (NEGF) formalism to determine Device Density of States (DDOS), Electrostatic Effective Potential (EDP), Conductivity (G) and Current-Voltage (I-V) characteristics. This paper analyzed the performance of semiconducting graphene nanoribbon (N=10), metallic graphene nanoribbon (N=11) and cascade hetero-graphene nanoribbon to consider the effect of H2O adsorption on GNR and conclude that for low voltage application semiconducting A-GNR will be a better choice over metallic A-GNR and cascade A-GNR. The optimum area for adsorbing maximum number of H2O molecules on A-GNR has been studied. It has been observed that the increment of quasi conductance resulting sensing performance for limited number of H2O adsorption. To overcome this problem, a new device model has been proposed.

Browse

Recent Submissions