Effect of water pretreatment on CO<Subscript>2</Subscript> capture using a potassium-based solid sorbent in a bubbling fluidized bed reactor

A bubbling fluidized bed reactor was used to study CO₂ capture from flue gas by using a potassium-based solid sorbent, sorbKX35 which was manufactured by the Korea Electric Power Research Institute. A dry sorbent, sorbKX35, consists of K₂CO₃ for absorption and supporters for mechanical strength. To increase initial CO₂ removal, some amount of H₂O was absorbed in the sorbent before injecting simulated flue gas. It was possible to achieve 100% CO₂ removal for more than 10 minutes at 60°C and a residence time of 2 s with H₂O pretreatment. When H₂O pretreatment time was long enough to convert K₂CO₃ of sorbKX35 into K₂CO₃ · 1.5H₂O, CO₂ removal was excellent. The results obtained in this study can be used as basic data for designing and operating a large scale CO₂ capture process with two fluidized bed reactors. This work was presented at the 6 ^th Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006.     

Investigation of the interfacial reaction between multi-walled carbon nanotubes and aluminum

Aluminum (Al)/carbon nanotube (CNT) composite films were fabricated by sputtering pure Al on the surface of aligned multi-walled CNT arrays. Heat treatment was performed in the temperature range 400–950 °C. The interfacial reaction between the Al and the CNTs was investigated by annealing the samples at various temperatures. The results indicated that aluminum carbide (Al₄C₃) was formed at the interface between the Al and CNT layers, and microscopy observation revealed that the reaction generally occurred at locations containing an amorphous carbon coating, at defect sites, and at open ends of CNTs. Because the nanosized CNTs are precursors for carbide formation, the Al₄C₃ formed is also nanoscale in size. The carbide formed on the surface as well as on the tips of the CNTs improves the interfacial interaction between the CNTs and the Al layers. This also contributes to the enhancement of the mechanical properties of the composite. Our investigation demonstrated that chemical vapor deposited CNTs are a suitable candidate as reinforcing material for Al and other metal matrices.     

Physical property and electrical conductivity of electroless Ag-plated carbon fiber-reinforced paper

The addition of a large amount of conductive filler to paper in order to increase electrical conductivity adversely affects some physical properties of the paper. Hence, it is desirable that conductive paper can be manufactured by adding only a small amount of conductive filler. Reinforced paper was manufactured by adding (1) electroless Ag-plated carbon fiber or (2) activated carbon fiber to the pulp. We investigated the effects of adding Ag-plated carbon fiber on the microstructure, physical properties, electrical conductivity, etc., of the paper. We found that the addition of a small amount of Ag-plated carbon fiber to the pulp made it possible to manufacture conductive paper with a high level of electrical conductivity and great physical strength.     

Synthesis of monodisperse nickel‐coated polymer particles by electroless plating method utilizing functional polymeric ligands

In the electroless plating process, to omit a sensitizing process with SnCl₂, we utilized amino‐functional groups on polymer particles. At first, highly monodisperse functional polymer particles could be prepared by a two‐step seeded polymerization of styrene, divinylbenzene, and glycidyl methacrylate. Then, surface epoxy‐functional groups were converted to amino‐functional groups by treating the particles with a diamine. By using these surface amino functionalities, we tried to prepare uniformly metal‐coated monodisperse polymer particles by electroless plating method. The constituents of an electroless nickel solution bath are nickel salt, a reducing agent, suitable complexing agents, and stabilizers. And the metal thickness was simply controlled by changing the loading amount of substrate polymer particles. Morphological observation of nickel‐plated polymer particles was conducted by using optical microscopy, scanning electron microscopy, and transmission electron microscopy. The structural composition of plated nickel was also investigated. Most of all, the function and the efficiency of the amino‐functional group of polymer particles as a polymeric ligand for metal binding was elucidated. From all observations, it was evident that in the electroless metal plating process without any sensitization step, the deposition of metal clusters on substrate particles is largely dependent upon the particle surface functionality. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3801–3808, 2006     

In situ self-organization of carbon black–polyaniline composites from nanospheres to nanorods: Synthesis, morphology, structure and electrical conductivity

Nanostructured composites of polyaniline (PANI) with carbon black (CB) were synthesized by an in situ self-organization process. The synthesis is based on the polymerization of aniline in a micellar solution of p-toluenesulfonic acid (TSA) with different weight percentages of CB using ammonium peroxydisulfate (APS) as the oxidizing agent. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), UV–vis spectroscopy, and the four-probe meter were used to study the morphological, structural, thermal, and electrical properties of CB–PANI nanocomposites. The results demonstrate that the morphology, thermal stability, and electrical conductivity of the nanocomposites were significantly influenced by the content of CB. SEM results reveal that there was a transition in morphology from composite nanospheres to one-dimensional (1D) composite long nanorods with an increase of CB content. XRD and UV–vis spectra results revealed that there was an increase in the crystallinity and a shift of quinoid transition bands towards lower wavelengths as the amount of CB in the composite increased. The mechanism for the formation of nanostructured composites was explained on the basis of the self-organization of micelles. CB–PANI nanocomposites with a maximum electrical conductivity of 1.38 S/cm were obtained; this is at least three orders of magnitude higher than that of pristine PANI.     

Colonization and Infection of the Skin by S. aureus: Immune System Evasion and the Response to Cationic Antimicrobial Peptides

Staphylococcus aureus (S. aureus) is a widespread cutaneous pathogen responsible for the great majority of bacterial skin infections in humans. The incidence of skin infections by S. aureus reflects in part the competition between host cutaneous immune defenses and S. aureus virulence factors. As part of the innate immune system in the skin, cationic antimicrobial peptides (CAMPs) such as the β-defensins and cathelicidin contribute to host cutaneous defense, which prevents harmful microorganisms, like S. aureus, from crossing epithelial barriers. Conversely, S. aureus utilizes evasive mechanisms against host defenses to promote its colonization and infection of the skin. In this review, we focus on host-pathogen interactions during colonization and infection of the skin by S. aureus and methicillin-resistant Staphylococcus aureus (MRSA). We will discuss the peptides (defensins, cathelicidins, RNase7, dermcidin) and other mediators (toll-like receptor, IL-1 and IL-17) that comprise the host defense against S. aureus skin infection, as well as the various mechanisms by which S. aureus evades host defenses. It is anticipated that greater understanding of these mechanisms will enable development of more sustainable antimicrobial compounds and new therapeutic approaches to the treatment of S. aureus skin infection and colonization.     

Field Evaluation of the Bacterial Volatile Derivative 3-Pentanol in Priming for Induced Resistance in Pepper

Plants are defended from attack by emission of volatile organic compounds (VOCs) that can act directly against pathogens and herbivores or indirectly by recruiting natural enemies of herbivores. However, microbial VOC have been less investigated as potential triggers of plant systemic defense responses against pathogens in the field. Bacillus amyloliquefaciens strain IN937a, a plant growth-promoting rhizobacterium that colonizes plant tissues, stimulates induced systemic resistance (ISR) via its emission of VOCs. We investigated the ISR capacity of VOCs and derivatives collected from strain IN937a against bacterial spot disease caused by Xanthomonas axonopodis pv. vesicatoria in pepper. Of 15 bacterial VOCs and their derivatives, 3-pentanol, which is a C8 amyl alcohol reported to be a component of sex pheromones in insects, was selected for further investigation. Pathogens were infiltrated into pepper leaves 10, 20, 30, and 40 days after treatment and transplantation to the field. Disease severity was assessed 7 days after transplantation. Treatment with 3-pentanol significantly reduced disease severity caused by X. axonopodis and naturally occurring Cucumber mosaic virus in field trials over 2 years. We used quantitative real-time polymerase chain analysis to examine Pathogenesis-Related genes associated with salicylic acid (SA), jasmonic acid (JA), and ethylene defense signaling. The expression of Capsicum annuum Pathogenesis-Related protein 1 (CaPR1), CaPR2, and Ca protease inhibitor2 (CaPIN2) increased in field-grown pepper plants treated with 3-pentanol. Taken together, our results show that 3-pentanol triggers induced resistance by priming SA and JA signaling in pepper under field conditions.     

Direct observation on the temperature-dependent change of magnetic domains in epitaxial MnAs film on GaAs (001)

We present a systematic change of the magnetic domain structure with temperature in epitaxial ferromagnetic MnAs film on GaAs (001), observed in a wide temperature range of 15-45 degrees C by magnetic force microscopy. Interestingly, it is found that, as temperature increases, the domain structure within the ferromagnetic alpha-MnAs stripes shows a mixture of head-on and simple domains at 15 degrees C and then, takes a complete transition to simple ones above 15 degrees C. This change could be understood by change in the demagnetizing factor of the cross-section of the ferromagnetic stripes with temperature.     

Development of a robot assisted carotid blood flow measurement system

The ultrasound diagnosis of the carotid artery is one of the most common non-invasive methods to detect early stage heart and cerebrovascular diseases. However, the precision and repetitiveness of the probe positioning depend exclusively on the operator's skills and dexterity. For this purpose, we propose the development of a robot assisted system to enhance the accuracy and repetitiveness of the probe positioning to measure the wave intensity (WI) index. In this paper, the Waseda-Tokyo Women's Medical-Aloka Blood Flow Measurement Robot System No. 2 Refined (WTA-2R) is presented. The WTA-2R consists of a conventional ultrasound diagnosis system, a 6-DOFs parallel link slave manipulator, a 6-DOFs serial link passive arm, and a master device. Experiments were carried out to verify its effectiveness in terms of accuracy and required time to perform the task. From the experimental results, the positioning accuracy and reduction of required time were confirmed.     

Effects of fiber aspect ratio, fiber content, and bonding agent on tensile and tear properties of short-fiber reinforced rubber

Both tensile and tear properties of short-fiber reinforced Chloroprene rubber have been studied as functions of the fiber aspect ratio and fiber content. Both properties increased when both the fiber aspect ratio and fiber content were increased. The fiber reinforced rubbers exhibited maximum values of these properties at a fiber aspect ratio of about 300. When the fiber aspect ratio exceeds 400, the mechanical properties decreased with the fiber content because of the non-uniform dispersion of fibers. The tensile modulus was compared with the prediction by the Halpin-Tsai equations for randomly oriented cases. A bonding agent was used in the fiber treating process. It was found that the ultimate tensile strength, torque, tearing energy and tensile modulus of the rubbers with treated fibers were much higher than those with untreated ones.