Isothermal and non-isothermal kinetic and safety parameter evaluation of tert-butyl(2-ethylhexyl)monoperoxy carbonate by differential scanning calorimetry

Tert-butyl(2-ethylhexyl)monoperoxy carbonate (TBEHC) 95 mass% is intrinsically a very unstable substance that can induce self-decomposition even under normal atmospheric condition. During storage, TBEHC 95mass% can release an enormous amount of heat if the temperature is higher than the recommended storage temperature, due to the self-accelerating reaction having been ignited. In this study, TBEHC 95mass% was tested by differential scanning calorimetry (DSC) under five heating rates (1, 2, 4, 6, and 8 °C/min) and four isothermal conditions (120, 125, 130, and 135 °C) to evaluate the basic kinetic and safety parameters of time to maximum rate (TMR), self-accelerating decomposition temperature (SADT), and temperature of no return (TNR). Under runaway reaction TBEHC 95 mass% releases a great quantity of heat. This study establishes an important guiding principle for related manufacturing processes worldwide.     

Spark Parameter Monitoring Feedback System for Preparation of Nanosilver Colloid in EDM

This study developed a system monitoring the electric discharge machine's (EDM) discharge energy and success rate to replace conventional oscilloscope observation. By using logic circuit, the signals are transmitted to the PC monitoring platform in order to display the discharge success times, discharge success rate, and electrode's consumption energy. The advantage of the proposed system is the capability to observe real-time discharges and record the experimental conditions, as well as optimize the discharge parameter settings. The experimental results suggest that, in the preparation of nanosilver colloid, the cost-performance of T_on–T_off at 10–100 µs is the optimal setting. The monitoring system also can take advantage of the discharge success rate to control the energy consumption of the electrode to obtain the standardization of products. The results suggest that, while discharge success rate, electrode's weight loss and wavelength of the absorption peak are considerably accurate, but concentration accuracy is relatively poor. The discharge success rate monitoring system is an innovative method that can help to realize electric discharge processing, optimize product quality, and it may be a powerful processing tool in the future.     

Managing Clouds, Smart Networks and Services: A Report on APNOMS 2011

This article presents a report on APNOMS 2011, which was held September 21–23, 2011 in Taipei, Taiwan. The theme of APNOMS 2011 was “Managing Clouds, Smart Networks and Services.”     

On building a medical diagnostic system of acute exanthemas

Abstract

In this paper, we present a multi‐purpose medical diagnostic system named AEA — the Acute Exanthem Advisor, and the methodologies of its implementation. AEA provides an accurate diagnosis of acute exanthemas and a complete environment including a user‐friendly interface, reviewing function, record keeping function and explanation function. Therefore, it may serve as an assistant, a record keeper or an educational tool. A prediction program is also provided which is capable of predicting the number of potential patients who are going to have acute exanthemas in the near future. To illustrate the processes of the consultation and the prediction of the AEA, an example is given. Finally, for the 25 different test cases given to the diagnosticians and the AEA, the answers are almost the same, so we can conclude that the performance of the AEA is satisfactory. Now, we are trying to extend the AEA system to be a medical diagnostic net for acute exanthemas, which will be able to be remote accessed through network communications.     

The structural and optical properties of ZnO nanowire arrays prepared by hydrothermal synthesis method

ZnO nanowire arrays have been grown on the ZnO film-coated silicon (100) substrates by hydrothermal method, and the deposited nanowires are found to have a uniform size distribution with sharp hexagonal-shaped tips. The structural and optical properties of the nanowires were investigated using atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and cathodoluminescence (CL) techniques. The XRD and SEM results demonstrate that the well-aligned ZnO nanowires are single crystalline structure formed along the c-axis orientation. TEM analysis further confirms that the ZnO nanowires are highly preferred grown along the (002) crystal plane. The spacing between adjacent (002) lattice planes is estimated as 0.52 nm. The optical properties of the nanowires were measured using CL after annealing in oxygen and nitrogen atmospheres at 550 °C for various times. The CL spectra in the visible spectrum exhibit two weak deep-level emission bands that may be attributed to the intrinsic or extrinsic defects. It can be observed that the ZnO nanowires show different optical behaviors after various annealing times. The dependence of the optical properties on the annealing conditions is also discussed.     

Accumulation and Toxicity of Superparamagnetic Iron Oxide Nanoparticles in Cells and Experimental Animals

The uptake and distribution of negatively charged superparamagnetic iron oxide (Fe₃O₄) nanoparticles (SPIONs) in mouse embryonic fibroblasts NIH3T3, and magnetic resonance imaging (MRI) signal influenced by SPIONs injected into experimental animals, were visualized and investigated. Cellular uptake and distribution of the SPIONs in NIH3T3 after staining with Prussian Blue were investigated by a bright-field microscope equipped with digital color camera. SPIONs were localized in vesicles, mostly placed near the nucleus. Toxicity of SPION nanoparticles tested with cell viability assay (XTT) was estimated. The viability of NIH3T3 cells remains approximately 95% within 3–24 h of incubation, and only a slight decrease of viability was observed after 48 h of incubation. MRI studies on Wistar rats using a clinical 1.5 T MRI scanner were showing that SPIONs give a negative contrast in the MRI. The dynamic MRI measurements of the SPION clearance from the injection site shows that SPIONs slowly disappear from injection sites and only a low concentration of nanoparticles was completely eliminated within three weeks. No functionalized SPIONs accumulate in cells by endocytic mechanism, none accumulate in the nucleus, and none are toxic at a desirable concentration. Therefore, they could be used as a dual imaging agent: as contrast agents for MRI and for traditional optical biopsy by using Prussian Blue staining.     

Rattle‐Structured Ag/TiO2 Nanocomposite Capsules with Bactericide and Photocatalysis Activities

A structural design featuring rattle‐type silver/titania (Ag/TiO₂) core/shell, that is, Ag@TiO₂, composite microcapsules is produced. The TiO₂ shell protects the encapsulated, movable Ag nanoparticles from breaking away under moderate loading, minimizing hence adverse environmental and biological exposure due to the metal loss, whereas the mesoporous shell serves as conduits for Ag ions released from the caged Ag nanoparticles to kill Escherichia coli in aqueous solutions under dark condition. The anatase TiO₂ shell imparts an additional, synergistic photocatalysis activity under ultraviolet irradiation. A pronouncedly enhanced photocatalysis activity results when the Ag@TiO₂ composite capsules were thermally annealed under vacuum. This “rattle‐in‐ball” hybrid architecture enables bifunctional bactericide and photocatalysis capability under both light and dark conditions, as well as mitigated environmental and biological impact in practical use.     

Predicting shrinkage and warpage of fiber-reinforced composite parts

One major problem that arises in the design of plastic parts, especially those that are fiber reinforced, is the change of shape and dimension as a result of shrinkage and warpage. These material inhomogeneities are caused by flowinduced fiber orientation, curing, poor thermal mold lay-out, and other processing conditions. This paper presents a simulation that predicts shirnkage and warpage of 3-D compression molded fiber reinforced composite parts. The simulation represents the structure with the 3-noded shell elements used in mold filling simulations. The calculated results indicate that fiber orientation strongly affect the final properties, which vary with different chage locations, have a significant effect on warpage. Unsymmetric curing, caused by uneven mold temperatures, could lead to a thermal moment that could possibly help reduce warpage.     

Improved thin film stability of differently formulated,printed, and crosslinked polymer layers against successive solvent printing

Interface control remains a top challenge of solution-processed organic light emitting diodes (OLED) stacks since the device performance heavily relies on it. Film stability of an inkjet deposited and crosslinked layer against subsequent exposure to a suitable inkjet printed solvent has been investigated. Impact of processing solvent (solvent used to prepare the polymer layer) on solution-cast thin film properties has already been shown for polymer films. To our knowledge, this study is the first one analyzing thin films stability against solvent exposure using technology relevant materials processed via inkjet printing (IJP). The outcome of this research showed that the stability of the crosslinked films is affected by the solvent used for ink formulation. These findings are of great interest for multilayered semiconductors devices, such as OLEDs, field-effect transistors and dye-sensitized solar cells. Differential scanning calorimetry (DSC) was used to quantify the efficiency of the polymer crosslinking reaction in pure powder and in thin films, as processed from different solvents. Crosslinking efficiency measured by DSC correlated well with the deformation induced by the solvent and observed on layer surfaces. The interaction in solution between polymer and solvent has also been evaluated to explain its impact on thin film stability against successive solvent printing. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48895.