Thermophysical properties of polypropylene/aluminum composites

This article is dedicated to the study of the thermal parameters of composite materials. A nonlinear least‐squares criterion is used on experimental transfer functions to identify the thermal conductivity and the diffusivity of aluminum‐polymer composite materials. The density measurements were achieved to deduce the specific heat and thereafter they were compared to values given by differential scanning calorimetry measurement. The thermal parameters of the composite material polypropylene/aluminum were investigated for the two different types of aluminum filler sizes. The experimental data were compared with several theoretical thermal conductivity prediction models. It was found that both the Agari and Bruggeman models provide a good estimation for thermal conductivity. The experimental values of both thermal conductivity and diffusivity have shown a better heat transport for the composite filled with large particles. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 722–732, 2004     

Synthesis of substituted amido-isogranulatimide analogues as potential checkpoint1 kinase inhibitors

Two new regioisomeric series of substituted amido-isogranulatimide analogues were prepared in three steps from 2-imidazol-1-yl-1H-indol-5-ylamine. The experimental conditions of the last photocyclization step were determinant to obtain one or the other series.     

Aspects of the capillary GC analysis of all-trans- and 13-cis-acitretin

The capillary gas chromatographic (CGC) analysis of the der-matological drug trans-acitretin (Neotigason^R) and its cis metabolite is described. Separation of the methyl ester derivatives can be achieved on a 90% biscyanopropylsiloxane phase. The importance of using cold on-column injection and short, thin film capillary columns is discussed. For patients treated with the prodrug of acitretin, etretinate (Tigason^R), i.e. the ethyl ester of Neotigason, three compounds have to be separated. Selectivity tuning is required for successful CGC separation. An alternative can be found in the selectivity of ion monitoring mass spectroscopy. Analysis of plasma samples involves liquid-liquid extraction, a derivatization step, and HPLC purification.     

Hamiltonian pancyclic graphs

The class of 3-connected bipartite cubic graphs is shown to contain a non-Hamiltonian graph with only 78 vertices and to have a shortness exponent less than one.     

Numerical analysis of steady-state and transient charge transport in organic semiconductor devices

A one-dimensional numerical model for the simulation of organic semiconductor devices such as organic light-emitting devices and solar cells is presented. The model accounts for the energetic disorder in organic semiconductors and assumes that charge transport takes place by a hopping process between uncorrelated sites. Therefore a Gaussian density of states and the use of the Fermi-Dirac statistics are introduced. The model includes density-, field- and temperature- dependent mobilities as well as the generalized Einstein relation. The numerical methods to solve the underlying drift-diffusion problem perform well in combination with the novel physical model ingredients. We demonstrate efficient numerical techniques that we employ to simulate common experimental characterization techniques such as current-voltage, dark-injection transient and electrical impedance measurements. This is crucial for physical model validation and for material parameter extraction. We also highlight how the numerical solution of the novel model differs from the analytical solution of the simplified drift-only model.     

Lagrangian Curves in a 4-Dimensional Affine Symplectic Space

Lagrangian curves in \(\mathbb {R}^{4}\) entertain intriguing relationships with second order deformation of plane curves under the special affine group and null curves in a 3-dimensional Lorentzian space form. We provide a natural affine symplectic frame for Lagrangian curves. It allows us to classify Lagrangian curves with constant symplectic curvatures, to construct a class of Lagrangian tori in \(\mathbb {R}^{4}\) and determine Lagrangian geodesics.     

Sodium magnesium sulfate decahydrate,Na2Mg(SO4)2·10H2O,a new sulfate salt

The structure of synthetic disodium magnesium disulfate decahydrate at 180 K consists of alternating layers of water‐coordinated [Mg(H₂O)₆]²⁺ octahedra and [Na₂(SO₄)₂(H₂O)₄]²⁻ sheets, parallel to [100]. The [Mg(H₂O)₆]²⁺ octahedra are joined to one another by a single hydrogen bond, the other hydrogen bonds being involved in inter‐layer linkage. The Mg²⁺ cation occupies a crystallographic inversion centre. The sodium–sulfate sheets consist of chains of water‐sharing [Na(H₂O)₆]⁺ octahedra along b, which are then connected by sulfate tetrahedra through corner‐sharing. The associated hydrogen bonds are the result of water–sulfate interactions within the sheets themselves. This is believed to be the first structure of a mixed monovalent/divalent cation sulfate decahydrate salt.