Permeation of benzene through liquid surfactant membranes

The effect of time on the permeation of benzene through aqueous surfactant membranes formed with two non-ionic surfactants has been studied on a batch scale under two different conditions of surfactant concentration and hydrocarbon: water ratio in the emulsions. The data have been correlated by an equation based on Casamatta's model of hydrocarbon permeation from an emulsion drop. The results indicate that the correlation can be used to treat the data until the onset of membrane rupture. The membrane thickness depends on the hydrocarbon: water ratio in the emulsion, and varies from about 1.57 to 5.10 μm.     

Correcting Image Distortion for Adaptive Cruise Control

One of the main drivers for intelligent transportation systems is safety. Adaptive cruise control, as a common solution for traffic safety, has extended from radars to cameras. Due to high mobility of vehicles and unevenness of roads, the picture quality of cameras has been great challenges for camera-based adaptive cruise control. In this paper, an image distortion correction algorithm is addressed. Our method is based on optical flow technology which is normally applied in motion estimation and video compression research. We are the first to attempt to adapt it in image distortion correction. Two optical flow approaches, the Lucas-Kanade method and the Horn-Schunck method, are selected and compared. The procedure of image distortion correction using the optical flow method has been tested by both synthetic test images and camera images. The experimental results show that the Lucas-Kanade method is more suitable in the correction of image distortion.     

Modeling of graphene-based field-effect transistors through a 1-D real-space approach

In this work, we present a computationally efficient approach for atomistic simulations of graphene nanoribbon (GNR), bilayer graphene (BLG) and bilayer graphene nanoribbon (BLGNR) field-effect transistors. The simulation scheme, which involves the self-consistent solutions of the non-equilibrium Green function method (NEGF) and 2-D Poisson’s equation, is based on the tight binding Hamiltonian in a 1-D real-space basis. We show that the Hamiltonian matrix for smooth edge GNRs and graphene can be expressed by 1 \(\times \) 1 size coupling matrices, which provides easy solutions for NEGF equations and largely reduces the computational time for simulation. The BLG and BLGNR can be described by the two coupled single-layer GNR Hamiltonian matrices, which allows the modeling of these devices by the same transport equations as GNR-FET with small modifications. Furthermore, the developed transport models are verified with the previously reported simulation and theoretical results.     

Free Vibration Analysis of Thin Circular Cylindrical Shell with Closure Using Finite Element Method

Vibration analysis of a thin circular cylindrical shell with closure is conducted using finite element method (FEM). Theoretically, shell vibrates in different axial modes, m; circumferential modes, n; and any of their combinations with corresponding modal frequencies. The present FEM results are verified by the results reported in the literature using various shell theories. The eigenvalues of the shell are extracted using block Lanczos and subspace iteration methods, in order to investigate their computational efficacy. Further, the effect of adding various types of closures at one end of the circular cylindrical shell such as flat, cone, and dome, on the modal frequencies are investigated. The two aspect ratios (length to radius ratio) of shell with closure, broad, and slender are considered for this study. The effect of the ratio of the thickness of the closure to the thickness of shell wall on the frequency is also investigated. For the shell with the closure, the vibration modes can be cylinder, closure, or combined cylinder and closure. The modal frequency of the cylindrical shell is significantly affected by the closure. The lowest frequency is observed in the flat type of closure in both the broad and slender cylindrical shells in comparison to the non-closure, dome, and cone type of the closures.     

SOLUBILISED WAXES AND THEIR INFLUENCE ON THE FLOW PROPERTIES OF LUBE OIL BASE STOCKS

The physico-chemical properties of Lubricating oil base stocks (LOBS) are generally influenced by the type/nature and concentration of solubilised waxes present in them. Detailed composition of the solubilised waxes, saturates and aromatics present in LOBS and its distillate fractions has been sludied. Further the influence of these solubilised waxes and as well of saturates/aromatics on the flow properties particularly pour point, viscosity and viscosity temperature relationship of LOBS sample and its distillate fractions have been investigated. The response of a commercial pour point depressant additive with varying composition of solubilised waxes in lube oil base stock sample has also been studied.     

Using Holographic Microscopy To Measure the Effect of Confinement on Crowding Agents in Lipid Vesicles

The hydrodynamic effects of macromolecular crowding inside cells are often studied in vitro by using polymers as crowding agents. Confinement of polymers inside cell-sized droplets has been shown to affect the diffusion of small molecules. Here we develop a method, based on digital holographic microscopy, to measure the diffusion of polystyrene microspheres that are confined within lipid vesicles containing a high concentration of solute. We apply the method to three solutes of varying complexity: sucrose, dextran, and PEG, prepared at ∼7 % (w/w). We find that diffusion inside and outside the vesicles is the same when the solute is sucrose or dextran that is prepared below the critical overlap concentration. For poly(ethylene glycol), which is present at a concentration higher than the critical overlap concentration, the diffusion of microspheres inside vesicles is slower, hinting at the potential effects of confinement on crowding agents.