The intelligent on-line monitoring of end milling

The main topics discussed in this paper include sensor integration, data extraction, data processing, monitoring the cutting tool, safety of the tool machinery, and quality of the components in processing. The detection method used in this paper is to extract the workload of a spindle motor from a CNC controller, and then transmit the data via a I/O card for further processing. The computer is connected to the CNC by DNC and is able to detect abnormal conditions and transmit, through DNC, to CNC the NC program to stop the machine or to replace the cutting tool. The systematic architectural instrument develops tools with object-oriented professional software and establishes software structure using a visual component library. The software component structure is made easy for maintaining and extending programs and for the operating system with its graphics user interface.     

Dimethylsilylbis(1‐indenyl) zirconium dichloride/methylaluminoxane catalyst supported on nanosized silica for propylene polymerization

A dimethylsilylene‐bridged metallocene complex, (CH₃)₂Si(Ind)₂ZrCl₂, was supported on a nanosized silica particle, whose surface area was mostly external. The resulting catalyst was used to catalyze the polymerization of propylene to polypropylene. Under identical reaction conditions, a nanosized catalyst exhibited much better polymerization activity than a microsized catalyst. At the optimum polymerization temperature of 55°C, the former had 80% higher activity than the latter. In addition, the nanosized catalyst produced a polymer with a greater molecular weight, a narrower molecular weight distribution, and a higher melting point in comparison with the microsized catalyst. The nanosized catalyst's superiority was ascribed to the higher monomer concentration at its external active sites (which were free from internal diffusion resistance) and was also attributed to its much larger surface area. Electron microscopy results showed that the nanosized catalyst produced polymer particles of similar sizes and shapes, indicating that each nanosized catalyst particle had uniform polymerization activity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Micellar layer-by-layer synthesis of TiO2/Ag hybrid particles for bactericidal and photocatalytic activities

Silver nanoparticles prepared by a reverse micelle process were sequentially deposited on rutile-structured TiO₂ particles via an electrostatic layer-by-layer (LbL) deposition together with a hydrophilic/hydrophobic interaction. The TiO₂ surface was first mediated by a preferential adsorption of poly(allylamine hydrochloride) (PAH) cationic molecules, before being mixed with the Ag nanoparticles encapsulated in reverse micelles consisting of anionic surfactant of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in isooctane. The deposition of Ag nanoparticles was not of a uniform coverage on the TiO₂ surface, but of a heterogeneous growth of the Ag particles on the TiO₂ surface. Antibacterial activity of the composites against gram-negative bacteria, i.e., Escherichia coli (E. coli), was found to increase with the deposition cycle, resulted mainly from the increased Ag concentration. The bactericidity is persistent in the absence of ultraviolet (UV) light. Over the concentration range of Ag examined, i.e., Ag/Ti atomic ratio varies from 0.28% to 0.53%, photocatalytic efficiency of the composites against methylene blue (MB) dye in an aqueous solution also improved pronouncedly with the silver concentration under UV exposure.     

In Vitro Characterization of Neutralizing Hen Antibodies to Coxsackievirus A16

Coxsackievirus A16 (CA16) is one of the major causative agents of hand, foot, and mouth disease (HFMD). Children aged <5 years are the most affected by CA16 HFMD globally. Although clinical symptoms of CA16 infections are usually mild, severe complications, such as aseptic meningitis or even death, have been recorded. Currently, no vaccine or antiviral therapy for CA16 infection exists. Single-chain variable fragment (scFv) antibodies significantly inhibit viral infection and could be a potential treatment for controlling the infection. In this study, scFv phage display libraries were constructed from splenocytes of a laying hen immunized with CA16-infected lysate. The pComb3X vector containing the scFv genes was introduced into ER2738 Escherichia coli and rescued by helper phages to express scFv molecules. After screening with five cycles of bio-panning, an effective scFv antibody showing favorable binding activity to proteins in CA16-infected lysate on ELISA plates was selected. Importantly, the selected scFv clone showed a neutralizing capability against the CA16 virus and cross-reacted with viral proteins in EV71-infected lysate. Intriguingly, polyclonal IgY antibody not only showed binding specificity against proteins in CA16-infected lysate but also showed significant neutralization activities. Nevertheless, IgY-binding protein did not cross-react with proteins in EV71-infected lysate. These results suggest that the IgY- and scFv-binding protein antibodies provide protection against CA16 viral infection in in vitro assays and may be potential candidates for treating CA16 infection in vulnerable young children.     

Rare earth element cerium substituted Ca–Si–Mg system bioceramics: From mechanism to mechanical and degradation properties

Cerium (Ce)-substituted diopsides (CaMgSi₂O₆) with enhanced mechanical strength and bioactivity were fabricated by precipitation method, followed by annealing at 1000 °C for 4 h. The mineralogical, morphological, in vitro biomineralization, degradation, and mechanical properties were investigated in order to assess the factors and mechanisms affecting the resultant properties. The X-ray diffractometer results showed that the onset of substitutional solid solubility in 0.25 mol Ce would result in new phase formation (cerium dioxide [CeO₂], and magnesium silicate [MgSiO₃]) further causing lattice instability. With increasing Ce dopant levels to 1.00 mol, the initial CaMgSi₂O₆ phase was completely replaced by new phases. The field-emission scanning electron microscopy results indicated that the 0.25 mol Ce had the best biomineralization performance in vitro, while less hydroxyapatite precipitates were found with further increasing Ce dopant levels, suggesting the new phases led to the hindrance of precipitates. The weight loss values indicated that the high dissolution rate of ions in the matrix was observed in the pure sample, while the high readsorption rate of ions in the simulated body fluid (SBF) occurred with increasing Ce dopant levels. The pH value and the inductively coupled plasma-mass spectrometer results suggested that the release of Ca and Mg ions controlled the pH value. The mechanical strength of matrices before SBF immersion was related to the phase transformation, the elastic modulus of CeO₂ and CaMgSi₂O₆, and the release of Mg ions, while the mechanical strength of matrices after SBF immersion was dominated by the structure of matrices.     

Effects of Thermal Radiation for Electronic Cooling on Modified PCB Geometry under Natural Convection

In this study, the discrete ordinates method (DOM) model is employed to estimate the effect of thermal radiation from multiple heat sources in a natural-convection flow field. It is found that the flow field around the chips can be altered by natural convection as induced by radiative heat transfer. The influence of thermal radiation is higher than 65% when the chipboard is in a vertical orientation. Furthermore, even if the chip surface temperature is only 317 K, the influence of radiative heat transfer is still up to 18%. Therefore, radiative heat transfer cannot be ignored for electronic component computational fluid dynamics simulation under natural convection.     

Roles of organic acids during exectrooxidation reaction over Pt-supported carbon electrodes in direct methanol fuel cells

A comprehensive study has been made to explore the role of organic acids on electrocatalytic performances of platinum (Pt) nanoparticles supported on carbon porous materials (CPMs) in proton exchange membrane fuel cells (PEMFCs). In particular, the effects of carboxylic acids (R–COOH), viz. formic acid, acetic acid, propionic acid, and butyric acid on catalytic activity, stability, and durability of anodic Pt/CPM electrocatalyst in direct methanol fuel cells (DMFCs) were investigated. In the presence of doped carboxylic acids, the electrooxidative activity of Pt/CPM follows the trend: HCOOH < CH₃COOH < C₂H₅COOH < C₃H₇COOH, revealing a consistent increase in the severity of catalyst deactivation with the number of carbons on the alkyl chain of the dopant. The Pt/CPM was found to exhibit electrocatalytic performances and tolerance for poisoning than a commercial Pt/XC-72 catalyst with a similar Pt loading (20 wt%). Moreover, a notable increase in mass activity up to ca. 150% over the spent Pt/CPM catalyst was observed up on removing the organic acid in the feed stream, indicating that catalyst poisoning by deactivation may be revived, even to its “intrinsic” activity.