Optical transmission utilizing injection light sources

Although a large amount of work in optical transmission has been accomplished through the use of lasers, modern developments have enabled noncoherent light sources also to be used in this area with great success. In particular, injection light sources?in the form of the coherent injection laser and the noncoherent light-emitting diode (LED)?offer designers of optical transmission systems characteristics that are in many ways superior to those of other methods. The present article deals essentially with how injection light sources may be employed to transmit or ``communicate' information optically. Such optical techniques can be used not only in communication systems, in the classic RF sense, but in computer, video, telemetry, and detection systems as well.     

Seismic response of a structure subjected to rotational base excitation

A modal superposition method which can perform the seismic analysis of a structure subjected to translational and rotational base excitation is presented. Discussed are two different approaches to derive the equations of motion. In the first approach, the reference axes are fixed in space. While in the second approach, they are rigidly fixed at the base of the structure. For rotational base excitation, it is shown that the application of second approach results in equation of motion with asymmetric, time-dependent coefficient matrix due to presence of the Coriolis acceleration term.Analytic integration is used to integrate the modal equations of motion derived by the first approach. Most of the mode shapes have to be included in the time history analysis.The modal superposition method is applied to the seismic analysis of a building subjected to translational and rotational excitation. The displacement results and the computer cost of this analysis are compared with those of using the direct integration method. The computer cost associated with the modal superposition method is lower than that associated with the direct integration method.     

Acrylic Homo- and Co-polymers Based on 2, 4-dichlorophenyl Methacrylate and 8-quinolinyl Methacrylate

The monomer 2, 4-dichlorophenyl methacrylate (2,4-DMA) was synthesized from 2, 4-dichlorophenol and characterized by conventional methods. The homopolymers of 2,4-dichlorophenyl methacrylate and its copolymers with 8-quinolinyl methacrylate (8-QMA) in different feed ratio were prepared by free radical polymerization using dimethyl formamide (DMF) as a solvent and 2,2-azobis iso butyronitrile (AIBN) as an initiator. The resulting polymers were characterized by using IR spectroscopy. Reactivity ratios of monomer were evaluated using UV-spectroscopy. Average molecular weights and polydispersity were determined by gel permeation chromatography (GPC). Solution viscosity was also obtained. The thermal analysis was carried out using TGA and DSC. The homo- and co-polymers were also tested for their antimicrobial properties against selected microorganism. The metal ion uptake capacity of synthesized copolymers was estimated by batch equilibration method using different metal ion solution under different experimental conditions. It is observed that due to the presence of pendant ester bound quinoline group, the copolymers are capable of adsorbing cations from their aqueous solution.     

Brain-computer interface design for asynchronous control applications: improvements to the LF-ASD asynchronous brain switch

The low-frequency asynchronous switch design (LF-ASD) was introduced as a direct brain-computer interface (BCI) technology for asynchronous control applications. The LF-ASD operates as an asynchronous brain switch (ABS) which is activated only when a user intends control and maintains an inactive state output when the user is not meaning to control the device (i.e., they may be idle, thinking about a problem, or performing some other action). Results from LF-ASD evaluations have shown promise, although the reported error rates are too high for most practical applications. This paper presents the evaluation of four new LF-ASD designs with data collected from individuals with high-level spinal cord injuries and able-bodied subjects. These new designs incorporated electroencephalographic energy normalization and feature space dimensionality reduction. The error characteristics of the new ABS designs were significantly better than the LF-ASD design with true positive rate increases of approximately 33% for false positive rates in the range of 1%-2%. The results demonstrate that the dimensionality of the LF-ASD feature space can be reduced without performance degradation. The results also confirm previous findings that spinal cord-injured subjects can operate ABS designs to the same ability as able-bodied subjects.     

Virtual three-dimensional blackboard: three-dimensional finger tracking with a single camera

We present a method for three-dimensional (3D) tracking of a human finger from a monocular sequence of images. To recover the third dimension from the two-dimensional images, we use the fact that the motion of the human arm is highly constrained owing to the dependencies between elbow and forearm and the physical constraints on joint angles. We use these anthropometric constraints to derive a 3D trajectory of a gesticulating arm. The system is fully automated and does not require human intervention. The system presented can be used as a visualization tool, as a user-input interface, or as part of some gesture-analysis system in which 3D information is important.     

HEAT TRANSFER IN MULTIPHASE CONTACTORS

A procedure for the prediction of wall-bed heat transfer coefficient for bubble columns and gas-solid fluidized beds is developed on the basis of hydrodynamic behavior of these contactors. A comparison between the predicted and experimental values of heat transfer coefficient over a wide range of design and operating variables is presented. An attempt is made to analyze the occurrence of maxima in heat transfer coefficient with respect to gas velocity in the case of fluidized beds. A procedure for the calculation of the optimum superficial gas velocity is outlined.     

Simulation of bubble populations in a gas fluidized bed

The dynamics of bubble populations in a gas fluidized bed have been analyzed using a simulation technique due to the authors [11,12]. It is shown that small bubble populations arising from progressive coalescence may lead to inherent fluctuations which may be considerable. Evidently, such fluctuations could manifest in conversions in fluidized bed reactors. The results obtained were based on a model due to Argyriou, List and Shinnar[1].     

Autonomous Line Scanning for SPC Telephone Switching Systems

An Autonomous Line Scanning Unit (ALSU) for completely autonomous detection of call originations in the SPC Telephone Switching System is described. Through its own memories, ALSU maintains an up-to-date record of subscribers' statuses, detects call originations, performs 'hit timing check' and informs the Switching System of the identity of calling subscribers. The ALSU needs minimum interaction with the Central Processor, resulting in increased call handling capacity.