In-situ synthesized poly(vinyl butyral)/MMT-clay nanocomposites: The role of degree of acetalization and clay content on thermal, mechanical and permeability properties of PVB matrix

Poly(vinyl butyral) - MMT clay nanocomposites were synthesized in situ with three different degrees of acetalization and with varying clay content for each vinyl butyral polymer ratio. The clay nano-platelet galleries were expanded, as determined by X-ray diffraction and TEM analysis. The glass transition temperature of the polymer nanocomposites were found to be similar to 56 degrees C and similar to 52 degrees C for the neat polymer and the 4% clay loaded samples, respectively. The 4 wt% clay loaded film showed higher strength and low strain to failure. The dynamic mechanical analysis also confirmed the improved stability of the matrix. The matrix with 0.5 butyral to alcohol ratio for 4 wt% clay exhibited good water vapor transmission compared to all other compositions. The encapsulated devices with 2.5 and 4 wt% clay loaded films increases the device life time and the efficiencies of these films were 50% higher than their encapsulated pristine polymer films. (C) 2015 Elsevier Ltd. All rights reserved.

The structure and the dynamics of poly(vinyl methyl ether) PVME and in PVME concentrated water solution : a study by neutron scattering and fully atomistic molecular dynamics simulations

175 p. : il.

Changes in the chloride content of ground water in Pinellas County, Florida between 1947 and 1956

In December 1956 the U. S. Geological Survey, in cooperation with the Florida Geological Survey and the Board of County Commissioners of Pinellas County, collected waterlevel and chloride content of water in 94 wells in Pinellas County. First sampled in 1947, resampling and reanalyzing the water from these wells was used to determine the change in the chloride content of the ground water from 1947 to 1956. The chloride content of ground water is generally a reliable indication of the contamination of ground water by sea water, as 90 percent of the dissolved solids of sea water are chloride salts. (PDF contains 15 pages.)

Application of microwave diagnostics to copper chloride and carbon dioxide lasers

Part A

A problem restricting the development of the CuCl laser has been the decrease in output power with increases of tube temperature above 400°C. At that temperature the CuCl vapor pressure is about .1 torr. This is a small fraction of the buffer gas pressure (He at 10 torr).

The aim of the project was to measure the peak radiation temperature (assumed related to the mean energy of electrons) in the laser discharge as a function of the tube temperature. A 24 gHz gated microwave radiometer was used.

It was found that at the tube temperatures at which the output power began to deteriorate, the electron radiation temperature showed a sharp increase (compared with radiation temperature in pure buffer).

Using the above result, we have postulated that this sudden increase is a result of Penning ionization of the Cu atoms. As a consequence of this process the number of Cu atoms available for lasing decrease.

PART B

The aim of the project was to study the dissociation of CO₂ in the glow discharge of flowing CO₂ lasers.

A TM₀₁₁ microwave (3 gHz) cavity was used to measure the radially averaged electron density n_e and the electron-neutral collision frequency in the laser discharge. An estimate of the electric field is made from these two measurements. A gas chromatograph was used to measure the chemical composition of the gases after going through the discharge. This instrument was checked against a mass spectrometer for accuracy and sensitivity.

Several typical laser mixtures were .used: CO₂-N₂-He (1,3,16), (1,3,0), (1,0,16), (1,2,10), (1,2,0), (1,0,10), (2,3,15), (2,3,0), (2,0,15), (1,3,16)+ H₂O and pure CO₂. Results show that for the conditions studied the dissociation as a function of the electron density is uniquely determined by the STP partial flow rate of CO₂, regardless of the amount of N₂ and/or He present. The presence of water vapor in the discharge decreased the degree of dissociation.

A simple theoretical model was developed using thermodynamic equilibrium. The electrons were replaced in the calculations by a distributed heat source.

The results are analyzed with a simple kinetic model.

Design for Survival: Sustainability for Planet and Structure

Buildings in Port Aransas encounter drastic environmental challenges: the potential catastrophic storm surge and high winds from a hurricane, and daily conditions hostile to buildings, vehicles, and even most vegetation. Its location a few hundred feet from the Gulf of Mexico and near-tropical latitude expose buildings to continuous high humidity, winds laden with scouring sand and corrosive salt, and extremes of temperature and ultraviolet light. Building construction methods are able to address each of these, but doing so in a sustainable way creates significant challenges. The new research building at the Marine Science Institute has been designed and is being constructed to meet the demand for both survivability and sustainability. It is tracking towards formal certification as a LEED Gold structure while being robust and resistant to the harsh coastal environment. The effects of a hurricane are mitigated by elevating buildings and providing a windproof envelope. Ground-level enclosures are designed to be sacrificial and non-structural so they can wash or blow away without imposing damage on the upper portions of the building, and only non-critical functions and equipment will be supported within them. Design features that integrate survivability with sustainability include: orientation of building axis; integral shading from direct summer sunlight; light wells; photovoltaic arrays; collection of rainwater and air conditioning condensate for use in landscape irrigation; reduced impervious cover; xeriscaping and indigenous plants; recycling of waste heat from air conditioning systems; roofing system that reflects light and heat; long life, low maintenance stainless steel, high-tensile vinyl, hard-anodized aluminum and hot-dipped galvanized mountings throughout; chloride-resistant concrete; reduced visual impact; recycling of construction materials.

Miscibility and Hydrogen Bonding in Blends of Poly(4-vinylphenol)/Poly(vinyl methyl ketone)

The miscibility and phase behavior of poly(4-vinylphenol) (PVPh) with poly(vinyl methyl ketone) (PVMK) was investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). It was shown that all blends of PVPh/PVMK are totally miscible. A DSC study showed the apparition of a single glass transition (T-g) over their entire composition range. When the amount of PVPh exceeds 50% in blends, the obtained T(g)s are found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are capable of forming interpolymer complexes. FTIR analysis revealed the existence of preferential specific interactions via hydrogen bonding between the hydroxyl and carbonyl groups, which intensified when the amount of PVPh was increased in blends. Furthermore, the quantitative FTIR study carried out for PVPh/PVMK blends was also performed for the vinylphenol (VPh) and vinyl methyl ketone (VMK) functional groups. These results were also established by scanning electron microscopy study (SEM).

Effect of chloride ions' introduction on structural, thermal stability, and spectroscopic properties in Yb3+Er3+-codoped germanate-bismuth-lead glasses

Yb3+Er3+-codoped chloride-modified germanate-bismuth-lead glasses have been synthesized by the conventional melting and quenching method. Structural and thermal stability properties have been obtained on the basis of the Raman spectra and differential thermal analysis, which indicate that the PbCl2 addition has an important influence on the phonon density of states, maximum phonon energy, and thermal stability of host glasses. The Judd-Ofelt intensity parameters and quantum efficiencies were calculated on the basis of the Judd-Ofelt theory and lifetime measurements. For the 1.53 mu m emission band, the full widths at the half-maximum increase and peak wavelengths are blueshifted with increasing PbCl2 content. Moreover, the effect of the PbCl2 addition on the phonon density of states, OH- content, and upconversion luminescence has been discussed and evaluated. Our results reveal that, with increasing PbCl2 content, the decrease of phonon density and OH- content contributes more to the enhanced upconversion emissions than that of maximum phonon energy. (c) 2005 Optical Society of America

Comparative investigation of up-conversion luminescence in Tm3+-doped oxide-chloride germanate and tellurite glasses

Tm3+-doped oxide-chloride germanate and tellurite glasses have been synthesized by conventional melting method. Intense up-conversion luminescence emissions were simultaneously observed at room temperature in these glasses. The possible up-conversion mechanisms are discussed and estimated. However, in these Tm3+-doped glasses, tellurite glass showed weaker up-conversion emissions than germanate glass, which is inconsistent with the prediction from the difference of maximum phonon energy between tellurite and germanate glasses. In this paper, Raman spectroscopy was employed to investigate the origin of the difference in up-conversion luminescence in the two glasses. Our results confirm that, besides the maximum phonon energy, the phonon density of host glasses is also an important factor in determining the up-conversion efficiency. (c) 2005 Elsevier Ltd. All rights reserved.

Effects of chloride substitution on the chemical and physical properties and the crystallization behavior in heavy metal fluoride glasses

Effect of the substitutions of chloride for fluoride on the chemical and physical properties and the crystallization behavior in heavy metal fluoride glasses has been investigated. The characteristic temperature of the glass does not changed obviously when the fluoride was taken place by chloride. Compared with samples of being free of ErF3, the doping samples are more inclined to be surface crystallization. Optical basicity in the glass system increases with increasing the negative charge provided by the chloride atoms and the absorption peak red shifted is observed in absorption spectra. XRD measurements show that not a single crystalline phase appears in the heated glass samples, which indicate the substitutions of chloride for fluoride with a variety of crystalline precipitation trends. (c) 2007 Elsevier B.V All rights reserved.

Observations on the inhibitory effect of sodium chloride on molds met with in smoked fishery products

Even though smoke curing is a very elegant method of preserving fish, the resultant products have only a very restricted shelf-life, unless stored under refrigerated conditions. The main source of spoilage is the early setting in of a vigorous growth of moulds. This problem is of a serious nature even in temperate climatic conditions. In full and universal recognition of the gravity of the problem, the FAO conference on herring technology held in September 1950 at Bergen in Norway has recommended the problem of "means of prevention of mould growth in smoked products" for future research study. This note records an interesting observation made at this Laboratory on the inhibitory action of sodium chloride on the development of mould in smoked fishery products.