Papers by Keyword: Molecular Interaction

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Authors: Rawat Jaisutti, Tanakorn Osotchan
Abstract: Molecular interaction between zinc phthalocyanine (ZnPc) thin films and various oxidizing gas molecules was examined by measuring sensor response of chemiresistor structures. The different response types can be obtained from the interactions to gas molecules of nitrogen dioxide (NO2), sulfur dioxide (SO2) and carbon monoxide (CO). For NO2 interaction, the response current of thermal evaporated ZnPc thin film with metal inter-digitaged pattern electrodes was proportionally increase to the concentration of NO2 gas. For measurement cycle, the NO2 gas at desired concentration was flowed into the measuring chamber for 20 minutes then the nitrogen gas was flowed for 20 minutes to recovering the interaction. The current response exhibited the step up and down during this measuring cycle and the heights of response step were proportional to the NO2 concentration. For SO2 measuring cycle, the response step increased at the beginning cycle then the response of ZnPc thin film seemed to be saturate and remained the same response step height even increasing the SO2 concentration. It was found that if the SO2 concentration was maintained at the same value for each measuring period, the response current was increase for the first few cycles after that the response step height decreased and became almost constant at lower value after passing more than ten measuring cycles. However this phenomenon can recover if the ZnPc surface was leaved in air for a few days. Therefore the interaction between ZnPc and SO2 molecules can modify the ZnPc surface and change the gas response. With the same measurement setup, it cannot found any significant change in the response current of the ZnPc film under the CO gas exposure up to concentration of 250 ppm. This result indicated that no interaction between ZnPc and CO molecules can be observed and these different responses on various gas molecules can demonstrate the selectivity of using ZnPc as a gas sensor.
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Authors: Sergio Neves Monteiro, Frederico Muylaert Margem, Noan Tonini Simonassi, Rômulo Leite Loiola, Michel Picanço Oliveira
Abstract: Natural fibers obtained from plants are being investigated as possible engineering materials with application in polymer composite reinforcement. For instance, the lignocellulosic fibers extracted from the leaves of the curaua plant (Ananas erectifolius) display a reinforcement potential owing to their relatively high strength. However, the curaua fiber has a poor adhesion with the polymeric matrix. In order to understand the curaua fiber interaction with a polymer matrix, the physical and chemical characteristics need to be evaluated. Among these characteristics, the Fourier transform infrared spectroscopy (FTIR) provides relevant information about the functional molecular groups and their possible interaction. Therefore, the objective of the present work was to analyze the FTIR of curaua fibers by means of transmittance spectrum obtained in the FTIR method with a 60o angle. The results showed peaks corresponding to specific molecular interaction that are discussed and compared to other results.
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Authors: A.N. Prajapati
Abstract: Static dielectric constant (ε0) and refractive index (n) have been experimentally determined for binary liquid mixture of n-Hexanol (HxOH) with Acetophenone (ACP) over the entire concentration range of mixture composition (0.0 →1.0) at constant temperature 303.15 K. Static dielectric constant (ε0) and refractive index (n) for the binary mixture have been measured using high precision LCR meter (0.2 MHz) and Abbe’s refractometer respectively. Excess of static dielectric constant (ε0)E and refractive index (n)E are determined and fitted with Redlich-Kister polynomial equation to derive the binary coefficients and standard deviations. Deviations of these parameters are discussed in terms of terms of molecular interaction between the constituent species. In the present work, comparative study of various mixing models for static dielectric constant (ε0) [Böttcher-Bordewijk (BOTT), Bruggeman (BRUG), Kraszewski (KRAZ), Looyenga (LOOY), Peon–Iglesias (P-I)] and for refractive index (n) [Oster (OST), Weiner (W), Eykman (EYK), Lorentz–Lorentz (L-L), Arago–Biot (A-G), Newton (Nw), Gladstone–Dale (G-D) and Erying–John (EJ)] have been carried out and their validity has been tested for the (n-HxOH+ACP) binary mixtures. The objective of the present work is to report the influence of nonassociative molecule on the molecular dynamics of associative molecules and validation mixing models.
131
Authors: Y. Mori, H. Yahara, Yuki Kamo, K. Hosokawa, Hideki Hashimoto
203
Authors: A.N. Prajapati
Abstract: Studies on Physico-chemical properties of binary liquid mixtures provide information on the nature of interactions between the constituent of the binaries. Literature provides extensive data on the static dielectric constant (ε0) and refractive index (n) of liquid compounds, but the combined study of all is quite scarce. In the present work static dielectric constant (ε0) and refractive index (n) have been experimentally determined for binary liquid mixture of 1-Propanol (PrOH) with Acetophenone (ACP) over the entire concentration range of mixture composition (0.0 →1.0) at constant temperature 303 K. Static dielectric constant (ε0) and refractive index (n) for the binary mixture have been measured using high precision LCR meter (0.2 MHz) and Abbe’s refractometer respectively. Excess of static dielectric constant (ε0)E and refractive index (n)E are determined and fitted with Redlich-Kister polynomial equation to derive the binary coefficients and standard deviations. For interaction and structural information various parameters namely, Kirkwood correlation factor (g), Kirkwood effective correlation factor (geff), Kirkwood angular correlation factor (gF) and Bruggeman parameter (fB) are determined for the binary mixtures. Variations of these parameters against the concentration of constituents are discussed in terms of molecular interaction between the constituent species.
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Authors: Tong Liu, Min Shan Liu, Qi Wu Dong
Abstract: The physical model and analytical method are put forward for considering the molecular interaction between solid wall and gas fluid when dealing with convective heat transfer in macro/mini/micro channels based on the boundary layer theory concept, the molecular kinetic theory of gases, structural chemistry and continuum hypothesis. The influence rule of wall-fluid intermolecular forces to the transport properties of gases located in boundary layer region is studied applying proposed models. The gas density variation distribution equation including the wall-fluid molecular interaction is derived with continuum media integral approach. The theoretical results show that the fluid diffusion is independent of the wall-fluid interaction but visosity and heat conductivity not. According to the gas molecular density distribution function and molecular dynamics, new formulae were developed for calculating viscidity coefficient and thermal conductivity with wall-fluid interacting effect for a fluid. The research results provide scientific reference for further study and exploitation on fluid flow and heat transfer of mini/micro channels. In addition, the formulae offered in this paper to compute the transport properties of gases are also suitable for fine analysis of boundary layer in macro-scale channels.
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