Vaporization Of Constituents Research Articles

A combinatorial approach of Monarda citriodora essential oil (MEO) and linalool vapors to control fruit rot of Citrus limon caused by a new pathogen, Aspergillus foetidus, and its underlying mode of action.

Citrus limon (lemon) is a widely cultivated citrus fruit. Significant postharvest losses due to fungi plague its production. Environmental and human health hazards have made the application of synthetic fungicides unsuitable. Despite the previous reports of antifungal activities of essential oil (EO) vapors, their synergistic combinations are understudied. Synergistic vapor combinations are advantageous due to less concentration of active components. This study aimed to isolate and identify postharvest fungal pathogens lemon and to evaluate the antifungal effects of synergistic Monarda citriodora EO (MEO)-constituent vapor combinations in vivo and in vitro. Postharvest fungal pathogens of lemon (C. limon) were isolated from various infected samples. The most pathogenic isolate was identified through morphology and its ITS-based rRNA gene sequencing as Aspergillus foetidus (O4). This is the first report of A. foetidus as a postharvest pathogen of lemon. The minimum fungicidal concentrations (MFCs) of MEO vapors treatment against O4 were 1346.15µL/L air. For carvacrol, hexanal, and linalool, MFC was same (96.16µL/L air). Checkerboard assays demonstrated that 1/4 MFC of MEO (336.54µL/L air) and 1/4 MFC of linalool (24.04µL/L air) (M+L) were synergistic against O4. M+L vapors reduced the O4 growth on lemons during storage by 64%±1.50% and preserved their quality (low weight loss %, unchanged pH, increased ascorbic acid content). Propidium iodide staining, ergosterol content analysis, calcofluor white staining and chitin content analysis revealed the integrity loss of the O4 plasma membrane and cell wall. 2',7'-Dichlorofluorescin diacetate staining revealed accumulation of intracellular reactive oxygen species (ROS), and scanning electron microscopy (SEM) analysis exposed the M+L treated mycelia with malformations. M+L vapors offer protection for lemons from A. foetidus and preserve their quality during storage.

General hypothesis governing the growth of single-crystal nanowires

The growth and growth rates of single-crystal nanowires by vapor phase mechanisms have been studied. A hypothesis has been proposed, which lays down foundation for the nanowire growth. It redefines the basic concepts of droplets from seeds and describes the fundamental basis of the adhesive properties of droplets. A set of droplet characteristics has been defined, a model in the framework of the hypothesis has been developed, and theoretical calculations have been performed. Experiments have also been carried out. Close correspondences between the theoretical and the experimental results lend support for the hypothesis and the model. Additional experimental evidences quantify the validity of the hypothesis. The calculated results resolve conflicts and controversies. They address the roles of catalysts in the growth of single-crystal nanowires. They shed light on the basic differences in the growth of thin and thick nanowires. They elucidate possible relationship between eutectic temperature and activation energy in the vapor-liquid-solid growth. They provide ground rules that govern the relative supplies of constituent vapor species for the growth of compound semiconductor nanowires. They explain how the same alloyed droplet (e.g., Au/Ga) is activated differently under the influence of different nonmetal elements of different nanowires (for example, As of GaAs, P of GaP, and N of GaN). They demonstrate, for example, that the nanowire growth may be achieved by means that creates thermodynamic imbalance and nanopores inside the seeds at temperatures far below the seed’s melting temperature. Alloying in the vapor-solid-liquid mechanism is one such means where growth of even thick nanowires (radius of rD≥50 nm) is possible at temperatures far below the eutectic temperature. The hypothesis, is called the simple, novel, and malleable (SNM) hypothesis. This hypothesis, together with the model, appears to have solved the basic origin of the nanowire growth. It demonstrates that various vapor phase mechanisms are essentially different forms of one and only one mechanism. They differ only to the extent that different techniques are employed in different mechanisms to create molten/semimolten seeds for nanowire growths.

Limits of recognition for simple vapor mixtures determined with a microsensor array.

The "limit of recognition" (LOR) has been defined as the minimum concentration at which reliable individual vapor recognition can be achieved with a multisensor array, and methodology for determining the LORs of individual vapors probabilistically on the basis of sensor array response patterns has been reported. This article explores the problems of defining and evaluating LORs for vapor mixtures in terms of the absolute and relative component vapor concentrations, where the mixture must be discriminated from those component vapors and from the subset of possible lower-order component mixtures. Monte Carlo simulations and principal components regression analyses of an extant database of calibrated responses to a set of 16 vapors from an array of 6 diverse polymer-coated surface acoustic wave sensors are used to illustrate the approach and to examine trends in LOR values among the 120 possible binary mixtures and 560 possible ternary mixtures in the data set. At concentrations exceeding the LOD, 89% of the binary mixtures could be reliably recognized (<5% error) over some composite concentration range, while only 3% of the ternary mixtures could be recognized. Most binary mixtures could be recognized only if the constituent vapor relative concentration ratio, defined in terms of multiples of the LOD for each vapor, was < or =20. Correlations with the Euclidean distance(s) separating the normalized constituent vapor response vectors allow reasonably accurate predictions of the limiting recognizable mixture composition ranges for binary and ternary cases. Results are considered in the context of using microsensor arrays for vapor detection and recognition in microanalytical systems.

Development of Automatic Adsorption Apparatus for Binary Mixture: Measurement of Individual Adsorption Isotherms of Ethanol and Water from Their Mixed Vapors by Active Carbon Fiber

The automatic adsorption apparatus has been developed to measure the individual adsorption isotherms of constituent vapor from binary mixed vapor. The present adsorption apparatus consists of a combination of gravimetry and volumetry. The weight increase due to gas adsorption was determined by the magnetic suspension vacuum balance with a sensitivity of 0.01 mg, while the pressure decrease due to adsorption was measured by a high precision pressure gauge with a sensitivity of 0.2 Pa. The adsorption data obtained from both gravimetry and volumetry make it possible to determine the individual isotherms of the constituent vapors without chemical analysis, if the molecular weights of the constituent vapors are significantly different one another. In the later part of this work, the present adsorption apparatus has been applied to measure the individual adsorption isotherms of ethanol and water by active carbon fiber from their mixed vapor. The reliability of the individual isotherms measured by the present apparatus has been considered. The adsorption data obtained in the present work clearly indicate that ethanol molecules are preferentially adsorbed into the micropores of active carbon fiber with a pore width of 0.67 nm. The present adsorption result suggests the possibility of the energy-saving separation of ethanol from the mixed vapors of ethanol and water.

Pulsed laser deposition of electronic ceramics

Pulsed laser deposition (PLD) is a unique physical vapor deposition technique which has gained considerable attention recently in the deposition of high quality, high temperature superconductors. In this technique, a short pulsed laser (<100 ns) is focused onto a target of the material to be deposited. The rapid heating, vaporization and plasma formation at the target surface result in a highly forward directed plume of atomic and gas phase species. Unique to this technique is the stoichiometric evaporation of multicomponent materials, irrespective of the individual constituent vapor pressures. Condensation of the stoichiometric plume onto heated single-crystal substrates results in the formation of single-phase, oriented thin films. Typically, depositions are performed in high pressures of reactive gas ambients. YBa 2Cu 3O 7-δ thin films deposited by PLD have excellent d.c. and high frequency transport properties. For YBa 2Cu 3O 7-δ epitaxial multilayer structures of superconductor/dielectric/superconductor are reported. Microwave devices fabricated from superconducting thin films and multilayer films have demonstrated significant performance improvements over devices fabricated from conventional materials. High quality ferroelectric thin films are also being deposited by PLD. The deposition and electrical characterization of oriented PbZr x Ti 1- x O 3 thin films are reported. PLD is shown as a versatile physical vapor deposition technique and will soon be an important industrial coating technique.