Application of PCA and SIMCA statistical analysis of FT-IR spectra for the classification and identification of different slag types with environmental origin.

In the past, different slag materials were often used for landscaping and construction purposes or simply dumped. Nowadays German environmental laws strictly control the use of slags, but there is still a remaining part of 35% which is uncontrolled dumped in landfills. Since some slags have high heavy metal contents and different slag types have typical chemical and physical properties that will influence the risk potential and other characteristics of the deposits, an identification of the slag types is needed. We developed a FT-IR-based statistical method to identify different slags classes. Slags samples were collected at different sites throughout various cities within the industrial Ruhr area. Then, spectra of 35 samples from four different slags classes, ladle furnace (LF), blast furnace (BF), oxygen furnace steel (OF), and zinc furnace slags (ZF), were determined in the mid-infrared region (4000-400 cm(-1)). The spectra data sets were subject to statistical classification methods for the separation of separate spectral data of different slag classes. Principal component analysis (PCA) models for each slag class were developed and further used for soft independent modeling of class analogy (SIMCA). Precise classification of slag samples into four different slag classes were achieved using two different SIMCA models stepwise. At first, SIMCA 1 was used for classification of ZF as well as OF slags over the total spectral range. If no correct classification was found, then the spectrum was analyzed with SIMCA 2 at reduced wavenumbers for the classification of LF as well as BF spectra. As a result, we provide a time- and cost-efficient method based on FT-IR spectroscopy for processing and identifying large numbers of environmental slag samples.

Effects of treated wastewater irrigation on the dissolved and soil organic carbon in Israeli soils.

In many arid and semi-arid regions, the demand for drinking water and other domestic uses is constantly growing due to demographic growth and increasing standard of living. Therefore, less freshwater is available for agricultural irrigation and new water sources are needed. Treated wastewater (TWW) already serves as an important water source in Israel since more than 40 years and its usage will further be extended. Related to its high loads with nutrients, salts and organic materials its use as irrigation water can have major effects on the soil physical, chemical and biological properties, in the worst case leading to soil degradation. Additional organic matter reaches the soil with the effluent water and soil microbial activity is stimulated. Soil organic carbon (SOC) seems to accumulate in the topsoil and tends to decrease after long-term irrigation with secondary TWW in the subsoil. The amount of dissolved organic carbon increased and the aromaticity of the organic compounds in the soil percolates decreased over the irrigation period. Priming effects, occurring after stimulation of microbial activity by the addition of easily degradable substances, could be found in the soils and were stronger for subsoil (1 m depth).

Transformation of dissolved organic matter (DOM) and 14C-labelled organic contaminants during composting of municipal biowaste.

Composting of municipal biowaste in the presence of 14C-labelled organic contaminants was studied in an attempt to characterize the mobilization potential of dissolved organic matter (DOM) for hydrophobic contaminants. The properties and transformation of DOM extracted from municipal biowaste compost with 10 mM KCl at six stages during 370 days of composting were investigated. DOM was fractionated into molecular weight fractions by ultrafiltration, and DOM structure was studied using CPMAS 13C-NMR- and UV-spectroscopy. The distribution of 14C-labelled model substances (DEHP, pyrene, simazine) upon molecular weight fractions was investigated by ultrafiltration, and association to DOM was studied performing flocculation experiments. The binding capacity of DOM for the model substances was of secondary influence for the mobilization because the intense biochemical reactions during composting pre-dominated the fate of the substances. Composting favoured the degradation of model substances to polar metabolites and supported their binding to the DOM matrix. DEHP and simazine were mainly found in the low- to medium-molecular DOM fraction and showed a small amount of DOM-associated radioactivity (approx. 10%). Pyrene and its metabolites had high affinities to high-molecular DOM. However, a direct relationship between DOM-quality and enhancement of pyrene solubility was not visible. After 120 days of composting DOM showed the highest binding capacity for hydrophobic contaminants.

The postoperative shoulder.

Because disability and pain may persist or recur after shoulder surgery, visualization of the postoperative shoulder before further treatment is of great interest. Postoperative status is reevaluated most frequently after rotator cuff repair, capsulorrhaphy in patients with chronic instability, and acromioplasty, where postoperative symptoms are clinically difficult to distinguish from rerupture or inadequate surgical results. Postoperative evaluation or follow-up after surgical treatment of tumors or surgical repair of shoulder injuries are other potential indications. Whereas surgical procedures for osseous components primarily will be evaluated by plain film radiographs, magnetic resonance imaging is a valuable tool for other sites of surgical treatment, such as soft-tissue components, with further potential indication for magnetic resonance arthrography. This article focuses on normal and abnormal postoperative findings in the shoulder, with emphasis of magnetic resonance imaging, and discusses specific findings based on magnetic resonance arthrography.