Synthesis and polymerization of the bromoacrylated plant oil triglycerides to rigid,flame‐retardant polymers

Simultaneous addition of bromine and acrylate to the double bonds of fatty acids in triglycerides was achieved. In the first part of the study, methyl oleate was bromoacrylated in the presence of acrylic acid and N‐bromosuccinimide as a model compound for the application of the reaction to the triglycerides. Next, soybean oil and high oleic sunflower oil were bromoacrylated by using the same procedure. The products were characterized by GC, IR, ¹H‐NMR, ¹³C‐NMR, and mass spectrometry. The bromoacrylation yields for soybean oil and sunflower oil were 75 and 55%, respectively. A rigid thermoset polymer was prepared from the radical copolymerization of bromoacrylated soybean oil with styrene. The bromoacrylated sunflower oil–styrene copolymer showed semirigid properties. The crosslinked network structure of the copolymers was examined by their swelling behavior in different solvents. Glass‐transition temperatures were also determined and soybean oil–based polymer and sunflower oil–based polymer showed a glass transition at 55–65 and 20–30°C, respectively. The storage moduli of the soybean‐based and sunflower‐based polymers at room temperature were approximately 1.0 × 10¹⁰ and 1.1 × 10⁸ Pa, respectively. Photopolymerization was also carried out by using 2,2‐dimethoxy‐2‐phenyl‐acetophenone as initiator. The response of the cured polymers to the thermal energy produced by a small flame was also tested by the ignition respond index method according to ASTM D 3713‐78 and was found to be 5 B at 2.00 mm. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:2700–2710, 2004     

Uptake of copper ions by carbon fiber/polymer hybrids prepared by tandem diazonium salt chemistry and in situ atom transfer radical polymerization

Cyclam-functionalized polyglycidyl methacrylate, grafted on carbon fibres (CF-PGMA-Cy) was prepared by atom transfer radical polymerization using aryl diazonium salt initiators. These adsorption maximum capacity of CF-PGMA-Cy fibres for Cu(II) was found to be 28.6 mg/g at pH 5.2 and the adsorption kinetics fitted to the pseudo-second order model. Cyclic voltammetry of the (CF-PGMA-Cy)-supported copper ions indicated true electrochemical stripping of Cu(II) with detection of as low as 2 pmol of adsorbed Cu⁰. CF-PGMA-Cy fibres are thus efficient and reusable adsorbents that hold promises for the design of electrochemical sensors of metal ions.     

Robust gesture recognition using feature pre-processing and weighted dynamic time warping

Gesture recognition is a technology often used in human-computer interaction applications. Dynamic time warping (DTW) is one of the techniques used in gesture recognition to find an optimal alignment between two sequences. Oftentimes a pre-processing of sequences is required to remove variations due to different camera or body orientations or due to different skeleton sizes between the reference gesture sequences and the test gesture sequences. We discuss a set of pre-processing methods to make the gesture recognition mechanism robust to these variations. DTW computes a dissimilarity measure by time-warping the sequences on a per sample basis by using the distance between the current reference and test sequences. However, all body joints involved in a gesture are not equally important in computing the distance between two sequence samples. We propose a weighted DTW method that weights joints by optimizing a discriminant ratio. Finally, we demonstrate the performance of our pre-processing and the weighted DTW method and compare our results with the conventional DTW and state-of-the-art.     

Subthreshold Mobility Extraction for SOI-MESFETs

Mobility calculation is a difficult task due to the stochastic nature of the particles in a device. This is especially true for a device operated in the sub-threshold region because the transport is a combination of diffusion and drift albeit diffusion dominated. As a result, one can calculate the mobility based on the drift and the diffusion techniques for a device operated in the subthreshold regime. We have developed a transport model, based on the solution of the Boltzmann Transport Equation, for modeling n-channel silicon-on-insulator (SOI) MOSFETs and MESFETs using the Ensemble Monte Carlo technique. All relevant scattering mechanisms for the silicon material system have been included in the model. The model is used to calculate both the diffusion coefficient and the drift based mobility and the results are compared with available experimental values. The mobility of the equivalent SOI MESFET device is a factor of 3–5 times higher than that of the MOSFET in the sub-threshold regime.     

A neuro-genetic approach to design and planning of a manufacturing cell

In this paper, we propose a neuro-genetic decision support system coupled with simulation to design a job shop manufacturing system by achieving predetermined values of targeted performance measures such as flow time, number of tardy jobs, total tardiness and machine utilization at each work center. When a manufacturing system is designed, the management has to make decisions on the availability of resources or capacity, in our setting, the number of identical machines in each work station and the dispatching rule to be utilized in the shop floor to achieve performance values desired. Four different priority rules are used as Earliest due date (EDD), Shortest Processing Time (SPT), Critical ratio (CR) and First Come First Serve (FCFS). In reaching the final decision, design alternatives obtained from the proposed system are evaluated in terms of performance measures. An illustrative example is provided to explain the procedure.     

Design of CWDM multiplexers based on series coupled ring resonators: analysis, potential and prospects on MEMS fabrication technologies

New designs for a 1 × 4 and a 1 × 8 CWDM multiplexers based on cascaded groups of series coupled ring resonators (Little et al. in J Lightwave Technol 15:998–1005, 1997; IEEE Photon Technol Lett 10:2263–2265, 2004; Hryniewicz et al. in IEEE Photon Technol Lett 12:320–322, 2000) are presented. Compared to other integrated optical alternatives such as MMI phasars (Paiam and MacDonald in Appl Opt 36: 5097–5108, 1997), cascaded Mach–Zehnder interferometers (Wang and He in J Lightwave Technol 23:1284–1290, 2005) and cascaded AWG (Dragone in IEEE Photon Technol Lett 3:812–815, 1991; Uetsuka in IEEE J Sel Top Quant Electron 10:393–402, 2004), the proposed circuits offer superior performance in their very sharp roll-off factor that exceeds 0.75, their reduced crosstalk level that lies below −60 dB and their negligible insertion loss for the 1 × 4 design. For the 1 × 8 design, the worst case insertion loss is 4 dB. However, the performances obtained exhibit passband ripples in the order of 5 dB, and besides, they are not very tolerant to fabrication errors. Being designed for SOI technology, the proposed circuits are compact as the circuit areas are 130 × 130 and 90 × 150 μm² for the 1 × 4 and 1 × 8 designs, respectively. They also have a high potential for MEMS tunability.     

Review of user parameter-free robust adaptive beamforming algorithms

This paper provides a comprehensive review of user parameter-free robust adaptive beamforming algorithms. We present the ridge regression Capon beamformers (RRCBs), the mid-way (MW) algorithm, and the convex combination (CC) as well as the general linear combination (GLC) approaches. The purpose of these methods is to mitigate the effect of small sample size and steering vector errors on the standard Capon beamformer (SCB). We also present sparsity based iterative beamforming algorithms, namely the iterative adaptive approach (IAA), maximum likelihood based IAA (referred to as IAA-ML) and M-SBL (multi-snapshot sparse Bayesian learning), which exploit sparsity to estimate the signal parameters. We provide a thorough evaluation of these beamforming methods in terms of power and spatial spectrum estimation accuracies, output signal-to-interference-plus-noise ratio (SINR) and resolution under various scenarios including coherent, non-coherent and distributed sources, steering vector mismatches, snapshot limitations and low signal-to-noise ratio (SNR) levels. Furthermore, we discuss the computational complexities of the algorithms and provide insights into which algorithm is the best choice under which circumstances.     

The room temperature annealing kinetics of stacking faults in cold worked alpha brasses

The room temperature annealing kinetics of stacking faults in cold worked alpha brasses were investigated by an X-ray diffraction technique. It was observed that the stacking fault probability in Cu-10 Zn alloy increases as a logarithmic function of time. This phenomena is associated with the segregation of zinc atoms to stacking faults. The ther mo mechanically treated (CW at RT, +720 h at RT, +18 h at 423 K and WQ) Cu-10 Zn alloy and also the Cu-20 Zn alloy showed an “abnormal narrowing” of stacking faults at room temperature. In order to explain this behavior, it was postulated that the partial dislocations relax under the action of the depleted area left behind them. In the Cu-30 Zn alloy the stacking fault probability showed a logarithmic decrease with respect to annealing time. This was interpreted as the relaxation of partial dislocations into their minimum energy configuration under the uniform solute impedance effect. A thermodynamic treatment of segregation to stacking faults was advanced for real multi-component solid solutions. The segregation of zinc atoms to the stacking faults in alpha brasses was calculated as a function of composition at room temperature using an IBM-360 computer. It was found that the maximum segregation to the stacking faults occurs in the Cu-6 Zn alloy.     

The room temperature annealing kinetics of stacking faults in cold worked alpha brasses

The room temperature annealing kinetics of stacking faults in cold worked alpha brasses were investigated by an X-ray diffraction technique. It was observed that the stacking fault probability in Cu-10 Zn alloy increases as a logarithmic function of time. This phenomena is associated with the segregation of zinc atoms to stacking faults. The ther mo mechanically treated (CW at RT, +720 h at RT, +18 h at 423 K and WQ) Cu-10 Zn alloy and also the Cu-20 Zn alloy showed an “abnormal narrowing” of stacking faults at room temperature. In order to explain this behavior, it was postulated that the partial dislocations relax under the action of the depleted area left behind them. In the Cu-30 Zn alloy the stacking fault probability showed a logarithmic decrease with respect to annealing time. This was interpreted as the relaxation of partial dislocations into their minimum energy configuration under the uniform solute impedance effect. A thermodynamic treatment of segregation to stacking faults was advanced for real multi-component solid solutions. The segregation of zinc atoms to the stacking faults in alpha brasses was calculated as a function of composition at room temperature using an IBM-360 computer. It was found that the maximum segregation to the stacking faults occurs in the Cu-6 Zn alloy.