Methane Hydrate Structure I Dissociation Process and Free Surface Analysis.

Methane hydrates are crystalline solids of water that contain methane molecules trapped inside their molecular cavities. Gas hydrates with methane as a guest molecule form structure I hydrates with two small dodecahedral cages and six tetra decahedral large cages. This study assesses the influence of occupation and the behavior of methane release from the molecular perspective during the dissociation process, particularly for the purpose of testing a series of molecular dynamics simulations.

Dataset for SO, SO, HSO and HO infrared absorption spectra at 300° C and 350° C temperatures.

The data presented here consists of library spectra obtained for use with a laser absorption spectroscopy gas sensor. The spectra include absorbance data for SO, SO, HO and HSO at 300° C and 350° C temperatures in two wavelength bands, 7-8 µm and 8-9 µm. Datasets were collected in a heated multi-pass absorption Herriott cell using two tunable external cavity quantum cascade laser sources, with the resulting transmission signal measured using a thermoelectrically cooled MCT detector.

Experimental studies on combined production of CH and safe long-term storage of CO in the form of solid hydrate in sediment.

The production of the confirmed enormous resources of CH trapped in permafrost and deep ocean sediments in the form of hydrates has been hampered by the lack of an extraction procedure that is both effective and environmentally sensitive. This research explores experimentally the dynamic rate limiting steps in the dissociation of methane hydrates and the formation of CO hydrates in a sediment matrix. The use of CO injection and substitution for hydrate extraction takes advantage of novel thermodynamics and also provides a safe storage option for greenhouse gas.

Impact of input field characteristics on vibrational femtosecond coherent anti-Stokes Raman scattering thermometry.

In this paper, three ultrashort-pulse coherent anti-Stokes Raman scattering (CARS) thermometry approaches are summarized with a theoretical time-domain model. The difference between the approaches can be attributed to variations in the input field characteristics of the time-domain model. That is, all three approaches of ultrashort-pulse (CARS) thermometry can be simulated with the unified model by only changing the input fields features.

Ultra-short pulsed off-axis digital holography for imaging dynamic targets in highly scattering conditions.

A single-shot digital holography system using an ultra-short pulsed laser is demonstrated to be very effective in suppressing the multiple-scattering noise associated with imaging dynamic targets in highly scattering environments, such as biological tissues and fuel injection systems. A planar off-axis reference wave configuration is used to generate a fixed carrier spatial frequency in the recorded holograms in order to separate coherent signal from incoherent noise in Fourier transformed holograms. The single-shot imaging system does not require averaging between multiple shots and can capture images of transient phenomena, such as the formation of diesel fuel injection sprays, and can overcome the problem of mechanical vibrations for recording holograms in industrial and laboratory environments.

Controlled continuous patterning of polymeric nanofibers on three-dimensional substrates using low-voltage near-field electrospinning.

We report on a continuous method for controlled electrospinning of polymeric nanofibers on two-dimensional (2D) and three dimensional (3D) substrates using low voltage near-field electrospinning (LV NFES). The method overcomes some of the drawbacks in more conventional near-field electrospinning by using a superelastic polymer ink formulation. The viscoelastic nature of our polymer ink enables continuous electrospinning at a very low voltage of 200 V, almost an order of magnitude lower than conventional NFES, thereby reducing bending instabilities and increasing control of the resulting polymer jet.

A transport model for nicotine in the tracheobronchial and pulmonary region of the lung.

Nicotine in mainstream cigarette smoke is predominantly present in the particulate phase. Interestingly, however, the deposition efficiency of smoke particles in the respiratory tract is less effective than is the nicotine retention. In the literature, four nicotine deposition mechanisms are identified: (a) direct gas deposition, (b) evaporative gas deposition, (c) particle deposition with evaporation, and (d) particle deposition with diffusion.

Particle size distribution of nicotine in mainstream smoke from 2R4F, Marlboro Medium, and Quest1 cigarettes under different puffing regimens.

Nicotine's dose and rate of delivery to the brain play an important role in its addiction and cardiovascular effects. Nicotine is mainly present in the particulate phase of cigarette smoke, and since particle size distribution controls the deposition behavior of particles in the respiratory tract, changes in the particle size distribution can produce variations in its regional and total dose to the lung. These variations can change its absorption rate and delivery to the brain.

Using large electric fields to control transport in microgravity.

Transport control by large electric fields in microgravity may be subdivided according to whether the charge carriers are flame ions, ions produced by corona discharges, or electrically charged particles. Using electric fields to induce and direct convection through the drag exercised on neutral gas by ions and to manipulate dispersions and trajectories of electrically charged droplets and particles is especially effective in the absence of Earth's gravity. We have explored applications associated with each of these, and this review collects and summarizes briefly the principal findings of our research, which is scattered widely over the literature of combustion, electrostatics, and experimental science.

Crossed two-beam coherent anti-stokes Raman spectroscopy in dispersive media.

Coherent anti-Stokes Raman spectroscopy (CARS) is a nonlinear optical wave mixing process that is used in gas-phase systems to determine the energy distribution of the probed species (usually N2) and, through a fitting procedure, the temperature giving rise to it. CARS signal strengths are maximized when the phase matching condition is met. Because gases are generally non-dispersive, this phase matching condition can be found geometrically as a function of the crossing angles between the CARS beams and their wavelengths.

Temperature field measurements of small, nonpremixed flames with use of an Abel inversion of holographic interferograms.

Interferometry has been used for many years as a semi-quantitative image-based diagnostic for combustion research. In this paper, we use image-plane, double-pulse holographic interferograms of axisymmetric flames to infer their radial temperature distribution. An Abel inversion is performed on the fringe data to account for line-of-sight integration through the flame.