A comparative study of delayed stroke handling approaches in online handwriting

International Journal on Document Analysis and Recognition (IJDAR) - Delayed strokes, such as i-dots and t-crosses, cause a challenge in online handwriting recognition by introducing an extra...     

Electroiniated cationic polymerization in the presence of addition-fragmentation agents

Summary Electrochemical initiation of cationic polymerization of heterocyclic and vinyl monomers such as cyclohexene oxide (CHO) and butyl vinylether (BVE), respectively at low potentials in the presence of allylic salts namely, allyl-thiophenium (AT), allyl-triphenyl phosphonium (APP), allyl-isoquinolinium (AIQ), allyl-pyridinium (AP) and allyl-dimethyl anilinium salts, was investigated. The mechanism of this polymerization was studied using cyclic voltammetry and by electropolymerization experiments performed in undivided and H-type cells. A mechanism involving addition-fragmentation decomposition of allylic salts by free radical species formed by electrolysis of trace amounts of water present in the system is postulated. Received: 6 September 2002/Revised version: 18 November 2002/ Accepted: 18 November 2002 Correspondence to Yusuf Yagci     

Oxidative polymerization of N‐vinylcarbazole in polymer matrix

A new class of soluble conductive poly(N‐vinylcarbazole) (PVCz) compounds has been developed by oxidative matrix polymerization of N‐vinylcarbazole (NVCz) by Ce(IV) in the presence of poly(ethylene glycol) (PEG). PEG was found to be a more suitable matrix with which to obtain a stable homogenous ternary complex solution when compared with poly(acrylic acid) (PAA) and poly(vinylpyrrolidone) (PVP). The role of PEG, NVCz and Ce(IV) concentration, order of component addition, the structure of the polymer matrix, molecular weight of polymer and the effect of solvent have been investigated. Obtaining soluble PEG–Ce(III)–PVCz ternary complexes was shown by cyclic voltammetric measurements, and the initial rate of formation NVCz cation radicals as calculated using UV–visible spectrophotometry. Advantageously with these soluble complexes, conductivities could be measured both in solution and in the solid state. © 2001 Society of Chemical Industry     

Uridine as additive in antisolvent for improving performance and reproducibility of perovskite solar cells

Journal of Materials Science: Materials in Electronics - Today, with their high efficiency of up to 25%, perovskite solar cells are the best alternative to silicon solar panels, which have...     

Effect of dentin and fiber post surface treatments with fumaric acid on the bonding ability of fiber posts

This study investigated the effects of fumaric acid on push‐out bond strength when applied to dentin surfaces and fiber posts. The root canals of 60 mandibular premolar teeth were instrumented and obturated. After removing two thirds of filling material, teeth were prepared according to six randomized groups (n = 10/group) defined by two fiber post surface treatments (0.7% fumaric acid or 9% hydrofluoric acid) and three dentin conditioning treatments [control (no conditioning); 17% ethylenediamine tetraacetic acid (EDTA); or 0.7% fumaric acid]. After fiber post‐cementation, three 1‐mm thick discs were obtained from each tooth by transverse sectioning, and each disc underwent push‐out bond strength testing. Data were analyzed with a one‐way analyses of variance (anova ) and t tests; p < .05 was considered statistically significant. Failure modes were determined by stereomicroscopy, and the surface characteristics of dentin and fiber posts were observed by scanning electron microscopy. Push‐out bond strength was greater for the group in which the post surface treated with hydrofluoric acid and the dentin surface treated with fumaric acid than the nontreated dentin and hydrofluoric acid‐treated post group (p < .05). There were no significant differences between other comparison pairs (p > .05). A combination of fumaric acid dentin conditioning and hydrofluoric acid fiber post treatment strengthened the bonding ability of fiber posts.     

Hierarchical cross-training in work-in-process-constrained systems

We study Work-In-Process (WIP)-constrained flowlines staffed by partially cross-trained workers with hierarchical skill sets. We characterize the optimal worker-to-task assignment policy for CONWIP systems with two workers and general stochastic processing times. This leads us to the “fixed-before-shared” principle, which states that a flexible worker should process a task he/she is uniquely qualified for before helping other workers with shared tasks. To provide insights on the performance opportunity of hierarchical cross-training in systems with limited WIP, we provide a complete characterization of the optimal policy and closed-form expressions of the resulting throughput for the case of exponential processing times. We extend our results to the more general case of floater workers, and illustrate their applicability to various real-world systems. Our analysis shows that hierarchical cross-training can provide significant benefits, but should be implemented with care in WIP-constrained environments such as those making use of pull systems.     

Diesel steam reforming with a nickel-alumina spinel catalyst for solid oxide fuel cell application

Liquid hydrocarbons (LC) are considered as fuel cells feed and, more particularly, as solid oxide fuel cell feed. Cost-effective LC-reforming catalysts are critically needed for the successful commercialization of such technologies. An alternative to noble metal catalysts, proposed by the authors in a previous publication, has been proven efficient for diesel steam reforming (SR). Nickel, less expensive and more readily available than noble metals, was used in a form that prevents deactivation. The catalyst formulation is a Ni-alumina spinel (NiAl₂O₄) supported on alumina (Al₂O₃) and yttria-stabilized zirconia (YSZ).SR of commercial diesel was undertaken for more than 15 h at high gas hourly space velocities and steam-to-carbon ratios lower than 2. Constant diesel conversion and high hydrogen concentrations were obtained. Ni catalyst characterization revealed no detectable amounts of carbon on the spinel catalyst surface Ni. The effect of catalyst composition (Ni concentration and YSZ presence) was studied to understand and optimize the developed catalyst. Two phenomena were found to be influenced by relative catalyst composition: water-gas-shift vs reforming reaction extent, and concentration of light hydrocarbons in products.