Optimal shape design for packaging containing heating elements by inverse heat transfer method

The present study is concerned with the determination of the optimal shape for a package containing multiple heating elements. The optimization tool has been developed based on the inverse heat transfer (IHT) approach, incorporating a direct problem solver, a numerical grid generator, a direct-differentiation sensitivity analyzer, and the conjugate gradient method. Shape design that leads to a specified outer surface temperature distribution is predicted by the approach. In this study, the effects of internal heat generation on optimal shapes of the packagings have also been evaluated. Several practical cases with various imbedded heating elements and thermal conditions are studied. Results show that the approach provides an efficient computer-aided design scheme for the shape profile determination.     

Determination of chlorine and pentachlorophenol in wood

Chlorine in wood was determined in connection with the development of a reference material (RM) of pentachlorophenol (PCP) in wood. The element was determined by photon activation analysis (PAA) using bremsstrahlung of 19 MeV electrons from an electron linear accelerator. The initial overall Cl content as well as the Cl remaining after extraction with methanol and subsequent extraction with water were determined. Moreover, the PCP fractions in the organic and in the aqueous extracts were analyzed by gas chromatography (GC). The results show that at least three quarters of the overall chlorine is bound in PCP and that PCP can be extracted to a high degree.     

Fabrication of a micro-direct methanol fuel cell using microfluidics

A direct-methanol fuel cell containing three parts: microchannels, electrodes, and a proton exchange membrane (PEM), was investigated. Nafion resin (NR) and polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (PS) were used as PEMs. Preparation of PEMs, including compositing with other polymers and their solubility, was performed and their proton conductivity was measured by a four point probe. The results showed that the 5 % Nafion resin has lower conductivity than the 5 % PS solution. The micro-fuel cell contained two acrylic channels, PEM, and two platinum catalyst electrodes on a silicon wafer. The assembled micro-fuel cells used 2 M methanol at the flow rate of 1.5 mL min^?1 in the anode channel and 5 × 10^?3 M KMnO₄ at the flow rate of 1.5 mL min^?1 in the cathode channel. The micro-fuel cell with the electrode distance of 300 ??m provided the power density of 59.16 ??W cm^?2 and the current density of 125.60 ??A cm^?2 at 0.47 V.     

Development of an HPLC-NMR method for the determination of PAHs in soil samples - a comparison with conventional methods

A hyphenated HPLC-(1)H NMR method for the identification and quantification of PAHs in soil samples has been developed and applied to a PAH reference sample provided by the Federal Institute for Materials Research and Testing (BAM, Berlin, Germany). The results were compared with those obtained by HPLC-DAD, HPLC-F, and GC-MS analyses of the same sample.     

Characterisation of commercially available linear alkylbenzenesulfonates by LC-SPE-NMR/MS (liquid chromatography-solid phase extraction-nuclear magnetic resonance spectroscopy-mass spectroscopy)

Commercially available linear alkylbenzenesulfonates (LASs) are a mixture of various homologues and isomers, leading to 20 major species. In this work we investigated the commercial product by liquid chromatography-solid phase extraction-nuclear magnetic resonance spectroscopy-mass spectrometry (LC-SPE-NMR/MS). The commercial product was separated into 17 fractions by liquid chromatography (LC). After chromatographic separation, 5% of the flow was split to a mass spectrometer (MS) while 95% was send to post-column solid phase extraction cartridges for enrichment of the analytes (LC-SPE). After elution from the SPE-cartridges a NMR-spectrometer equipped with a cryo-probe was used for the characterisation of the different LASs species. For the first time ¹H-1D and H-H-COSY spectra for 14 LASs species out of 20 major isomers are presented, whereas the 6 remaining species are detected as mixtures in 3 ¹H-1D and H-H-COSY spectra. These data were used to correlate the chromatographic retention of the LASs isomers to the substitution pattern of the alkyl chain.     

On Weaknesses of Non–surjective Round Functions

We propose a new attack on Feistel ciphers with a non-surjective round function such as the CAST cipher family and LOKI91. We extend the attack towards block ciphers that use a non-uniformly distributed round function and apply the extended attack to the CAST family. This attack demonstrates that the round function of a Feistel cipher with six to eight rounds needs to be surjective and sufficiently uniform.     

Plasmonic gold nanocrosses with multidirectional excitation and strong photothermal effect

We report a facile chemical synthesis of well-defined gold nanocrosses through anisotropic growth along both <110> and <001>, whereas gold nanorods grow only along either <110> or <001>. The multiple branching was achieved by breaking the face-centered-cubic lattice symmetry of gold through copper-induced formation of single or double twins, and the resulting gold nanocrosses exhibited pronounced near-IR absorption with a great extension to the mid-IR region. As studied by discrete dipole approximation (DDA) simulations, the entire nanocross gets excited even when one of the branches is exposed to incident light. The above properties make them useful as octopus antennas for capturing near-IR light for effective photothermal destruction of cells. The cell damage process was analyzed using the Arrhenius model, and its intrinsic thermodynamic characteristics were determined quantitatively. Besides effective photothermal treatment and two-photon luminescence imaging, the near- and mid-IR-absorbing gold nanocrosses may also find applications in IR sensing, thermal imaging, telecommunications, and the like.