Electrical conductivity of polyblends of poly(1,4-phenylene vinylene) and poly(2,5-dimethoxy-1,4-phenylene vinylene)

Summary A series of polyblends of poly(1,4-phenylene vinylene), PPV, and poly(2,5-dimethoxy-1,4-phenylene vinylene), PDMPV, were prepared in film form from precursor polyblends of the respective sulfonium salt polymers, which were separately prepared from the respectivebis(sulfonium salt) monomers. The blend films were doped with I₂ at room temperature to obtain a wide range of electrical conductivities (10^–2 to 10²Scm^–1) depending on the blend composition. The higher the content of PDMPV in the blends the higher was the conductivity.     

Evaluation of the performance of tight-UF membranes with respect to NOM removal using effective MWCO, molecular weight, and apparent diffusivity of NOM

Concepts for the effective MWCO of tight-UF membranes, and apparent diffusion coefficients for NOM, were introduced to determine the mechanisms influencing NOM removal and to explain the various behaviors of NOM removal by UF membranes with different hydrophobicities, permeability, and surface charges. Colloidal NOM (COM) and non-colloidal hydrophobic NOM (NCD HP) constituents were chosen for the evaluation of two different UF membranes. For a relatively hydrophobic, relatively high permeability, and less negatively charged UF membrane, the hydrophobic fractions of COM were preferentially removed and were also removed by a size exclusion mechanism (i.e., both hydrophobic interaction and size exclusion mechanisms). The NCD HP exhibited no such preferential removal of the hydrophobic fractions, but could be removed by a size exclusion mechanism (i.e., only size exclusion mechanism). With a relatively hydrophilic, relatively low permeability, and more negatively charged UF membrane, COM exhibited no preferential removal of the hydrophobic fractions, but could be removed by a size exclusion mechanism (i.e., only size exclusion mechanism). Whereas the hydrophobic fractions of the NCD HP were preferentially removed, these could not be removed by a size exclusion mechanism (i.e., only hydrophobic interaction mechanism). The apparent diffusion coefficients of NOM, as determined from NOM diffusion experiments using a diffusion cell equipped with a regenerated cellulose membrane, were much lower than those calculated by the Stokes-Einstein relation. The diffusion coefficient of NOM is expected to be used to predict and explain NOM transport behaviors in tight-UF membranes.     

Mechanical and thermal properties of ceramic‐modified poly(amide imide)

Poly(amide imide)–epoxysilane (coupling agent) composites were reacted with silica, a condensation product of tetraethylorthosilicate (TEOS), by a sol–gel process and were then cast into films. After this procedure, the chemical characteristics and mechanical and thermal properties were measured. Fourier transform infrared showed that silica existed in the poly(amide imide) matrix. When a proper amount of silica was added to the poly(amide imide) matrix, the tensile strength, elongation, and toughness increased greatly. A poly(amide imide)/30 wt % epoxysilane composite with 20 wt % TEOS had the best mechanical properties. Thermogravimetric analysis under nitrogen and oxygen atmospheres indicated that the char contents increased with the amount of silica. The glass‐transition temperatures of the poly(amide imide)–silica nanocomposites were observed around 170–180°C with differential scanning calorimetry. This approach may be a new method for the low‐temperature thermal curing of poly(amide imide). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1780–1788, 2004     

Adsorption and desorption characteristics of 2-methyl-4-chlorophenoxyacetic acid onto activated carbon

Adsorption and desorption characteristics of the 2-methyl-4-chlorophenoxyacetic acid (MCPA) from aqueous solution onto the activated carbon (GAC, F-400) were studied. Adsorption equilibrium capacities of the MCPA increased with decreasing pH and temperature of the solution. Adsorption equilibrium of the MCPA could be represented by the Sips equation. The internal diffusion coefficients were determined by comparing the experimental concentration decay curves with those predicted from surface diffusion model and pore diffusion model. The adsorption model based on the linear driving force approximation (LDFA) was used for simulating the adsorption behavior of the MCPA in a fixed bed. Over ninety five percent desorption of the MCPA could be obtained using distilled water.     

Model algorithmic control of grade change operations in paper mills

In this work, the Model Algorithmic Control (MAC) method is applied to control the grade change operations in paper mills. The neural network model for the grade change operations is identified first and the impulse model is extracted from the neural network model. Results of simulations for MAC control of grade change operations are compared with plant operation data. The major contribution of the present work is the application of MAC in the industrial plants based on the identification of neural network models. We can confirm that the proposed MAC method exhibits faster responses and less oscillatory behavior compared to the plant operation data in the grade change operations.     

Monodisperse polymer/metal composite particles by electroless chemical deposition: Effect of surface functionality of polymer particles

Micron‐sized polymer particles were coated with layers of nickel compounds by plating electrolessly in the presence of aqueous solutions of nickel chloride, sodium hypophosphite, sodium citrate, and ammonium chloride at elevated temperature. The uniform functional polymer particle could be obtained by seeded polymerization. To investigate the effect of surface functionality on the conditions for nickel deposition, the polymer particle was functionalized with the thiol group. From morphological observation, it was found that the mode of nickel deposition was greatly dependent on the surface functionality of the polymer particle. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 420–424, 2003     

Comparison of Three‐Dimensional Korean Male Anthropometric Data with Modeling Data Generated by Digital Human Models

The purpose of this study was first to extract the anthropometric data of typical Korean male adults, based on the three‐dimensional anthropometric data measured through the Size Korea project. The data were then analyzed to identify the differences in the anthropometric characteristics between typical Koreans and 3D Korean mannequinmannequins generated by digital human models. Revision equations were then suggested to improve the inaccuracy of digital human models. Typical Korean adults subject to the 3D body scan data were selected by factor analysis with respect to the 5th, 50th, and 95th percentiles. Comparisons of anthropometric differences included the differences of the height and length variables in the vertical direction and the breadth, depth, and circumference variables in the horizontal direction. These comparisons demonstrated the differences in the anthropometric characteristics between typical Koreans and Korean mannequins based on differences in body shape and proportions between Korean and Western populations. Typical Koreans have shorter legs and longer torso than those of such mannequins generated from their own modeling algorithms, and the body shape of Koreans is more of an inverted triangular shape compared to the models. Although 3D digital human models are required to be modified to appropriately reflect the Asian body shape, modification of the modeling algoritms is not available to the public. The revision equations that convert the Korean modeling data of RAMSIS and Human in CATIA into typical Korean anthropometric data were instead suggested by regression analysis. It is expected that the proposed revision equations will help the designer evaluate design alternatives and improve the suitability of ergonomic evaluation for Korean customers. © 2012 Wiley Periodicals, Inc.     

An analysis of muscles from ultrasound image using morphological information of fascia and thoracic vertebra

In this paper, we propose a new fully computerized image analysis method for measuring the thickness of muscles from ultrasound image obtained by muscle endurance test using morphological information of fascia and thoracic vertebra. Firstly, we divide the image into lumbar region and thoracolumbar region by the difference of density in image for measuring the thickness of muscles. In lumbar region, we notice that the intensity of fascia is relatively higher than other parts. Thus, we measure the thickness of muscles surrounding the fascia area. In the process, we apply median filter to candidate fascia areas for extracting candidate muscle layers between fascias. Then, the thickness of muscles we measure is that of the third layer. In thoracolumbar region, we apply region expansion method for classifying the region into subcutaneous fat part and part including thoracic vertebra. Then, we apply counting method and evolutionary computation search model to find the measuring location that is in between subcutaneous fat area and thoracic vertebra. In experiment, the proposed method is effective in measuring the thickness of muscles and avoids failures of previous studies. The performance of this approach is sufficiently comparable to that of medical experts.     

Digital evidence discovery of networked multimedia smart devices based on social networking activities

Unquestionably, networked multimedia smart devices are commonly adopted in contemporary ubiquitous wireless computing era with unprecedented evolving pace in terms of mobility, portability, and pervasiveness. Regrettably, those technology-oriented gadgets are phenomenally exploited by cyber criminals or get involved in computer-related incidents unknowingly. Substantively, the detection, prevention, and the related digital forensics of the above scenarios are becoming tremendously urgent both in public and private sectors. Therefore, in this research, we investigate the scenario when state-of-the-art wireless communication technologies are integrated with the networked smart devices where digital evidences may exist and they could be disclosed when appropriate standard operating procedures are suitably applied. Accordingly, in this paper, a PDA with the built-in GPS navigation functionality via the ubiquitous Wi-Fi connection to a popular social networking platform (facebook) is cross examined concerning the related digital evidence collecting and discovering in terms of revealing previous facebook user accounts on the mobile device without shutting off the power. The research provides a generic framework for the digital forensics specialists to contemplate when the networked smart devices are involved in the related criminal investigation cases especially when omnipresent social networking platforms are becoming the new avenue for the escalating, stringent, and heinous cybercrimes.     

Preparation of nano-sized silicon carbide powder using thermal plasma

Nano-sized silicon carbide (SiC) powder was prepared by thermal plasma process using silicon tetrachloride (SiCl₄) and methane (CH₄). The synthesized powder was characterized by X-ray diffraction pattern, scanning electron microscopy, transmission electron microscopy, FT-IR spectroscopy and particle size analyzer. The powder was dominated by β-SiC including some of α-SiC and free carbon species. The quality of the powder was varied with process conditions such as the molar ratio of H/Si and C/Si, and collecting positions. It was known that the conversion to SiC was mainly affected by the addition of hydrogen gas because it promoted the decomposition and reduction of SiCL. CH₄ was easily decomposed to carbon species for the formation of SiC as well as removal of impure oxygen, but excessive carbon suppressed the formation of crystalline SiC and resulted in the solid carbon contamination. The optimum ratio of H/Si was approx. 26 and that of C/Si was 1.1. For collecting positions, the powder collected at the vessel and filter was preferable to that at the reaction tube. The average size of the powder synthesized was estimated to be below 100 nm and uniform in distribution.