High-fidelity bilateral teleoperation systems and the effect of multimodal haptics.

In master-slave teleoperation applications that deal with a delicate and sensitive environment, it is important to provide haptic feedback of slave/environment interactions to the user's hand as it improves task performance and teleoperation transparency (fidelity), which is the extent of telepresence of the remote environment available to the user through the master-slave system. For haptic teleoperation, in addition to a haptics-capable master interface, often one or more force sensors are also used, which warrant new bilateral control architectures while increasing the cost and the complexity of the teleoperation system. In this paper, we investigate the added benefits of using force sensors that measure hand/master and slave/environment interactions and of utilizing local feedback loops on the teleoperation transparency. We compare the two-channel and the four-channel bilateral control systems in terms of stability and transparency, and study the stability and performance robustness of the four-channel method against nonidealities that arise during bilateral control implementation, which include master-slave communication latency and changes in the environment dynamics. The next issue addressed in the paper deals with the case where the master interface is not haptics capable, but the slave is equipped with a force sensor. In the context of robotics-assisted soft-tissue surgical applications, we explore through human factors experiments whether slave/environment force measurements can be of any help with regard to improving task performance. The last problem we study is whether slave/environment force information, with and without haptic capability in the master interface, can help improve outcomes under degraded visual conditions.     

Analysis of fair rate calculations in resilient packet ring aggressive mode

Resilient packet ring (RPR) standardized as IEEE 802.17 is a new medium access control (MAC) protocol for metro-ring networks. RPR supports spatial reuse which increases the achieved throughput but it can also result in congestion and starvation of nodes on the ring. Therefore, it is necessary to employ mechanisms to enforce a fair allocation of the ring bandwidth in RPR. In order to maintain fairness among nodes, a fairness algorithm is deployed at each RPR node. When a node detects congestion, it calculates a fair rate which is advertised to all upstream nodes contributing to congestion. Upon receiving the fair rate, the upstream nodes limit the rate of their injected traffic to the advertised fair rate. Consequently, the congested node can utilize the unused capacity and add its local traffic to the ring. In this paper, we develop an analytical model for fair rate calculation in the RPR aggressive mode fairness algorithm in the parking-lot scenario. This model provides an insight on dynamics of the RPR fairness algorithm and can be used to evaluate its performance. We investigate this problem in two cases. First, we assume that the link propagation delay is zero and derive the fair rate equations for this ideal case. We then consider the link propagation delay and develop a more realistic model. We verify the accuracy of our model by simulation results. Furthermore, we use the developed model to study the impact of various parameters on convergence of the fair rate.     

Five-Phase Interior Permanent-Magnet Motors With Low Torque Pulsation

High torque pulsation is a major disadvantage of most interior permanent-magnet (IPM) motor configurations. Choosing the proper number of stator slots and winding distribution as well as increasing number of phases are among the possible solutions for reducing torque pulsation. In this paper, five-phase IPM motor with fractional-slot stator is studied. It is shown that despite other IPM motors, the new five-phase IPM motor with fractional slot has a very low torque pulsation. For comparison purposes, a five-phase IPM motor with common configuration is also considered. It is shown that the torque pulsation of the proposed fractional-slot five-phase IPM motor is much lower than the conventional five-phase IPM motor. Nonlinear finite-element method is used to analyze different machine configurations. A prototype four-pole five-phase IPM motor with 15 stator slots has been built and is used for experimental verification     

Privacy aware image template matching in clouds using ambient data

Cloud computing is ideal for image storage and processing because it provides enormously scalable storage and processing resources at low cost. One of the major drawbacks of cloud computing, however, is the lack of robust mechanisms for the users to control the privacy of the data they farm out to the clouds. In this paper, we develop an image encoding scheme that enhances the privacy of image data that is outsourced to the clouds for processing. Unlike previously proposed image encryption schemes, our encoding scheme allows different forms of pixel-level image processing to take place in the clouds while the actual image is not revealed to the cloud provider. Our encoding scheme uses a chaotic map to transform the image after it is masked with an arbitrarily chosen ambient image. We use template matching as a common image processing task to demonstrate the ability of our scheme to perform computations on privacy enhanced images. A simplified prototype of the image processing system was implemented and the experimental results are presented in this paper.     

Bioreactor temperature profile controller using inverse neural network (INN) for production of ethanol

This paper presents the use of inverse neural networks (INN) for temperature control of a biochemical reactor and its effect on ethanol production. The process model is derived indicating the relationship between temperature, pH and dissolved oxygen. Using fundamental model obtained data sets; an inverse neural network has been trained using the back-propagation learning algorithm. Two types of temperature profile are used to compare the performance of the INN and conventional PID controllers. These controllers have been simulated in MATLAB for a quantitative comparison. The results obtained by the neural network based INN controller and by the PID controller are presented and compared. There is an improvement in the performance of INN controller in settling time and dead time and steady state error over the PID controller.     

Mesoporous SBA-15@n-Pr-THAM-ZrO organic–inorganic hybrid: as a highly efficient reusable nanocatalyst for the synthesis of polyhydroquinolines and 2,3-dihydroquinazolin-4 (1h)-ones

Journal of Porous Materials - In this work, tris(hydroxymethyl)aminomethane-Zirconium complex supported on modified SBA-15 (SBA-15@n-Pr-THMAM-ZrO) prepared as a novel mesoporous catalyst. The...     

Solubility Enhancement of Fe in ZnO Nanoparticles Prepared by Co-Precipitation Method

Journal of Superconductivity and Novel Magnetism - Crystalline ZnO offers an excellent host matrix to create a dilute magnetic semiconductor (DMS) owing to its facile Zn-atom substitution with the...     

Morphology, rheology and dynamic mechanical properties of PP/EVA/clay nanocomposites

This paper reports on morphology, rheology and dynamic mechanical properties of polypropylene (PP)/ethylene vinyl acetate (EVA) copolymer/clay nanocomposite system prepared via a single step melt compounding process using a twin screw micro-compounder. Scanning electron microscopic (SEM) investigations revealed that the dispersed phase droplet size was reduced with incorporation of an organo-modified montmorillonite (OMMT). This reduction was more significant in presence of a maleated PP (PP-g-MAH) used as compatibilizer. Phase inversion in the compatibilized blends caused a further decrease in PP droplet size. The OMMT gallery spacing was higher in nanocomposites with EVA as matrix which could be attributed to higher tendency of OMMT nanoparticles towards EVA rather than PP. This enhanced tendency was confirmed by rheological analysis too. Transmission electron microscopy (TEM) results also showed that the majority of OMMT nanoparticles were localized on the interface and within EVA droplets. According to dynamic mechanical analysis, the compatibilized nanocomposites showed higher storage and loss moduli due to better dispersion of OMMT layers. The modulus enhancement of nanocomposites as a function of OMMT volume fraction was modeled by Halpin-Tsai’s-Nielsen expression of modulus for nanocomposites. The results of modeling suggested that the aspect ratio of the intercalated OMMT, in the form of Einstein coefficient (K _E), plays a determining role in the modulus enhancement of nanocomposites.     

Amine corrosion and amine cracking of API 5L X52 carbon steel in the presence of hydrogen sulphide and carbon dioxide

In this research, stress corrosion cracking (SCC) and corrosion behaviour of API 5L X52 carbon steel in 25?wt-% diethanolamine solution, saturated/unsaturated with carbon dioxide and containing 0 and 200?ppm hydrogen sulphide at different temperatures were investigated using slow strain rate test, electrochemical measurement and microscopic analysis. In addition, the presence of heat stable amine salts (HSASs) in the test solution was studied using spectrophotometry and Fourier transform infra-red spectroscopy. Analysis of the results showed that the primary components to form HSASs exist in the solution. The results indicated that SCC is more likely in solutions without amine. Increase in corrosion rate of carbon steel by increase in temperature was clearly observed and concluded that the simultaneous presence of hydrogen sulphide and carbon dioxide in the solution can increase the corrosion rate of carbon steel more than having one of the gases in the solution.