ESR spectroscopy - an analytical tool for the glass industry

In the past, wet chemical methods have been developed for the quantitative analysis of polyvalent elements in glasses. The major disadvantage of these chemical methods is that all structural information is lost during analysis. In addition, the analysis of species by wet chemical methods is unreliable due to possible redox reactions during the decomposition process. Therefore, the emphasis is on the physical methods which can directly detect species in bulk glasses. Especially optical and ESR spectroscopy are suitable methods due to their wide range of applications and sensitivity. Concerning quantitative measurements, no comparison between ESR results and chemical analysis of species has been published so far. This work discusses the possible application of ESR spectroscopy in the glass industry by focussing on routine interpretation, the correlation to chemical procedures and quantitative analysis. Results are presented and discussed for iron and chromium in packaging glasses. For example an excellent correlation was found between the Fe3+ ESR signal and the chemically determined Fe3+ concentration in glass

Investigation of cat scratches on container glass

Cat scratches have become a chronic quality problem for the container glass industry but there is still controversy about their origin and how to eliminate them. Many tests related to appearance, shape, location, and chemical composition of this type of cord have therefore been made to get more information about them. As a result it can now be said that cat scratches are surface cords containing higher amounts of alumina and especially zirconia than the host glass. The cords form 10 to 20 µm thick bands located 10 to 60 µm below the surface. The origin of the problems is the corrosion of the refractory material. It is impossible to locate exactly the primary source because different mechanisms can create the cords. However, the main source is probably in the hot zone of the melter. The refractory-rich glass accumulates on the bottom of the tank where the overall flow makes it creep along the bottom of the whole furnace to the feeder outlet. The best ways to reduce the frequency of cat scratches are either appropriate drainage or mechanical stirring in the feeder channel

Alkali ion migration control from flat glass substrates

Sodium diffusion from flat glass substrates during annealing changes properties of refined flat glass. In the ease of the development of the CuInSe2 thin film solar eell, annealing at 550 °C is necessary for the formation of suitable crystalline phases. Sodium diffusing from the soda-lime-silica glass substrate influences crystal growth and the main electrical parameters of the solar cell. Different possibilities in sodium ion migration control are presented, considering the influence of glass composition on sodium diffusion and its chemical potential as well as passivation of sodium-containing glasses by diffusion barriers. Experimental results in connection with the thin film solar cell show that sodium-free substrates or glass compositions which immobilise sodium at tetrahedral sites of boron oxide or alumina can be used without further surface treatment. Soda-lime-silica glass with sputter-deposited AI2O3 and BiOx thin films or CVD coatings (SiNx: H, SiOx) as diffusion barrier coatings shows promise as a cheap substrate material. Alternatively, dealkalisation of soda-lime-silica glass in HCl atmosphere leads to silica-rich surfaces with excellent barrier properties. The investigations are carried out using various surface analytical tools like Auger Electron Spectroscopy (AES), X-Ray Diffractommetry under Grazing Incidence (GI-XRD), high-resolution Scanning Electron Microscopy (SEM), and Fourier Transform Infrared spectroscopy (FTIR)

Machining of silica glasses using excimer laser radiation

Various silica glasses were engraved deliberately by excimer laser radiation using wavelengths of 308 and 248 nm. The ablation of different samples was investigated by systematic Variation of the processing parameters. The ablation rates were determined using profilometry and gravimetric measurements by evaluating the processing quaUty and the morphology of the processed surfaces was considered. The phenomenon of ablation is explained as a non-linear interaction of the laser beam and the glass. The experimental results show that the ablation behaviour of silica glass depends on the wavelength and the intensity of the laser radiation, on the surface quahty and the degree of purity of the glass. Although high ablation rates were obtained, the suitability of excimer lasers for micromachining is restricted due to the rough surface morphology and poorly defmed edges

Eigenschaften von niedrigschmelzenden Phosphatgläsern

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Stress measurement in transparent materials using scattered laser light

For the manufacturing and application of glass products, knowledge about residual stresses inside the glass plays an important role.With the scattered light method stresses can be measured with high spatial resolution at each point of a glass specimen regardless of its dimensions and without destroying the glass. It enables measurement of the whole stress profile in a specimen and measurement of stresses near edges and holes or investigation of the influence of temperature treatment on a stress profile. Thermal stresses as well as mechanically induced stresses can be measured in glass plates and also in tubular glass products

Surface treatment of glass and ceramics using XeCI excimer laser radiation

A XeCl excimer laser with uniform beam profile and 308 nm wavelength was used for ablation and surface modification of technical glasses and ceramics.The ablation behaviour and the resulting surface morphology of the different materials were measured in dependence upon the energy density and the number of pulses. In contradiction to ceramics, glasses show a higher ablation threshold and considerable higher ablation rates. Due to the short wavelength of the excimer laser, microstructuring of glass and ceramic surfaces is possible. Examples are presented, like marking of glasses, microline structuring of float glass, as well as positive and negative microstructuring of ceramics

Zur Ausnutzung eines kompensatorischen Wachstumseffektes in der ökologischen Schweinemast

Due to a lack of organic feed with a high quality amino acid pattern it is difficult to achieve the required Lysine-Metabolisable-Energy-ratio in organic grower diets with the danger of reduced value creation. Hence, the present study should investigate whether a moderate oversupply of lysine in the finisher diet after a marginal lysine supply in the grower diet results in compensatory growth. 96 fattening pigs were divided into four groups characterised by different Lysine-ME-ratios in the grower/finisher diets (Experimental Group: 0.69/0.69; Negative Control Group: 0.69/0.59; Positive Control Group: 0.89/0.69; Regular Control Group: 0.89/0.59). Performance and carcass quality were recorded. The economic success was calculated under varying feed cost relevant organic pre-conditions. All groups were similar in performance. The experimental group and the negative control group showed similar but numerically lower lean meat percentages. The negative control group generated the best economic success. It is reasoned that fattening pigs show a certain degree of compensatory growth and that the conventional German lysine recommendations are too high for organic grower diets. Both key findings lead to the conclusion that 100 % organic pig fattening is a resolvable challenge

Ausnutzung eines kompensatorischen Proteinansatzes in der ökologischen Schweinemast

Durch den Mangel an Futtermitteln ökologischer Herkunft mit hochwertigem Aminosäurenmuster besteht die Gefahr zu geringer Lysingehalte in der Anfangsmastration im Vergleich zu den GfE-Bedarfsnormen, woraus eine zu starke Verfettung des Schlachtkörpers resultieren kann. Daher sollte in einer Untersuchung geklärt werden, ob nach einer Lysin-Unterversorgung in der Anfangsmast nach geeigneter Realimentation in der Endmast ein kompensatorischer Proteinansatz stattfindet. Dazu wurden 96 Mastschweine einer modernen Genetik (48 Kastrate, 48 Sauen) in 4 Gruppen mit unterschiedlich gestalteten Lysin-ME-Quotienten in der Anfangs-/Endmastration (Versuchsgruppe: 0,69/0,69; Negativkontrolle: 0,69/0,59; Positivkontrolle: 0,89/0,69; Kontrolle 0,89/0,59) auf Mastleistung, Proteinansatz, Schlachtkörperqualität, Fleischqualität sowie Wirtschaftlichkeit untersucht. Alle 4 Gruppen schnitten bei der Mastleistung (z.B. Lebendmassezunahme, Futterverwertung) und der Fleischqualität (z.B. pH-Werte, LF-Wert) gleich ab. Die N-Bilanz über Futter – Kot – Harn belegte einen kompensatorischen Proteinansatz für die Versuchsgruppe und die Negativkontrolle. Der Muskelfleischanteil (Schlachtkörperqualität) bewegte sich bei der Versuchsgruppe und der Negativkontrolle auf gleichem, aber tendenziell niedrigerem Niveau im Vergleich zur Positivkontrolle und zur Kontrollgruppe. Beim Überschuss des Erlöses über die Ferkel-Futter-Kosten konnte in unterschiedlichen Szenarien gezeigt werden, dass die Negativkontrolle mit steigenden Rationskosten zunehmend besser abschnitt. Das ist der Fall, je stärker durch Restriktionen im ökologischen Landbau der Rationsanteil von Futtermitteln nicht ökologischer Herkunft limitiert wird. Es wird geschlussfolgert, dass nicht auf ein ökonomisch relevantes Kompensationsvermögen beim Mastschwein geschlossen werden kann, und dass unter den spezifischen Fütterungsrestriktionen des ökologischen Landbaus die GfE-Empfehlungen zur Lysinversorgung für die Anfangsmast als zu hoch einzuschätzen sind

Hilft kompensatorisches Wachstum bei der Überwindung der Proteinlücke in der öklogischen Schweinemast?

Durch den Mangel an Futtermitteln ökologischer Herkunft mit hochwertigem Aminosäurenmuster besteht die Gefahr zu geringer Lysingehalte in der Anfangsmastration für hochleistende Mastrassen im Vergleich zu den DLG-Bedarfsnormen, woraus eine zu starke Verfettung des Schlachtkörpers resultieren kann