KINETICS FOR LOW TEMPERATURE PYROLYSIS OF BLACK LIQUOR

A kinetic study of pyrolysis of dried black liquor was performed using a Netzsch 429 Thermogravimetric Analyzer. It was found that as conversion increases from 10 to 45% the apparent pyrolysis activation energy for black liquor increases from 77.20 to 112.74 KJ/mol. For black liquor the order of reaction was found to be first-order. The reaction rate constant was found to be 2.12×10⁹ min. These results are in agreement with the data reported by other investigators on biomass pyrolysis.     

Mikrobielle Werkstoffzerstörung – Schadensfälle und Gegenmaßnahmen: Umweltrechtliche Belange

Microbial deterioration of materials – case histories and countermeasures: Legal aspects of environmental protection Biofouling is a natural process. Usually, it does not cause too much harm if taken care of properly. If biofouling is fought by special means, problems may arise. The waste water does not meet the due standards. Sometimes the recipe of the treatment agent is not known. If the treatment causes more problems than it can solve help is needed quickly. Yet, it is advisable to keep one's mind clear. Wrong help can become very expensive. In addition, legal punishment will follow, if environmental legislation is hurt. Damages of the environment will be payed by an insurance company only, if the risk is covered by the insurance contract in advance. The best way to be sure is to have a good lawyer, a good expert in environmental techniques and environmental legislation, a good insurance, and to anticipate possible risks.     

Low density lipoprotein catabolism is enhanced by the cleaved form of alpha-1-antitrypsin

The frequent occurrence of hypocholesterolaemia following inflammatory processes is well known but unexplained. Elevated plasma levels of serine proteinase inhibitors (serpins) and their complexes with target enzymes have been demonstrated in inflammatory, malignant and infectious diseases which are also often accompanied by low plasma cholesterol levels. Under inflammatory conditions, uncomplexed, but cleaved inactive serpins arising from slow deacylation of the serpin-proteinase complex may be present in the circulation. To determine the influence of native and cleaved forms of serpins, such as alpha-1-antitrypsin (AAT), on lipoprotein metabolism, we investigated the effect of these forms on low density lipoprotein (LDL) catabolism in human HepG2 cell line. We have found that the cleaved form of AAT in concentrations from 125 to 2000 nmol l-1 stimulates LDL binding to the HepG2 cells, by up to 49% with a subsequent increase in LDL uptake and degradation of up to 79 and 65% respectively. Native AAT was also found to increase LDL binding and internalization by 20-25%, independently of the amount of AAT added, an effect most probably due to the cleaved form of AAT produced by local proteolysis of native AAT incubated in the cell culture. Moreover we have shown that the cleaved form of AAT interacts with LDL in vitro, and that such an interaction abolishes AAT ability to stimulate LDL binding and internalization. This study for the first time describes the ability of the cleaved form of AAT to stimulate LDL binding and internalization in HepG2 cell culture, and provides evidence that hypocholesterolaemia occurring during inflammatory processes may be mediated by cleaved forms of serpins.     

Optimizing the service life of drill-collar joints on the basis of fracture mechanics criteria

A method of calculation of the lifetime of fish-mouth collar joints has been proposed that is based on selecting a model and using the criteria of fracture mechanics. By this method it is possible to optimize the design parameters of collar joints as a function of the cyclic crack resistance of steels. It is shown that the lifetime of a collar joint with a fatigue crack can be predicted, and the size of the crack can be estimated for a certain operating time of the collar joint. The critical values of the length of a fatigue crack were calculated for various types and dimensions of collar joints, which is important in fixing the periodicity of crack detection operations.     

Variability in the proliferative responsiveness of cultured human vascular smooth muscle cells to alpha-thrombin

alpha-Thrombin, a key enzyme of the coagulation cascade, is also a potent mitogen for many cell types. In the present study, the responsiveness to alpha-thrombin of cultured human vascular smooth muscle cells (HVSMC) derived from either vein or normal and atherosclerotic arteries was investigated. All HVSMC populations examined responded mitogenically to alpha-thrombin. However, the extent of this response varied between different cell populations. No significant differences were observed between HVSMC derived from vein versus artery or atherosclerotic versus normal tissues. The responsiveness of a specific HVSMC culture to alpha-thrombin was not affected by cell density and remained constant over several passages. Unlike platelet-derived growth factor BB (PDGF-BB), alpha-thrombin did not exhibit any significant chemotactic effects on HVSMC or induce their anchorage independent growth in semi-solid medium. The hypothesis that the observed variability in HVSMC responsiveness to alpha-thrombin is due to the heterogeneity of cultured HVSMC is raised and discussed.     

Production and properties of micro‐porous glas bubble zinc and aluminium composites

Micro‐porous syntactic foams were produced by means of integration of glass bubbles into aluminium and zinc matrices. Preforms of glass bubbles were pressure infiltrated with the alloys AlSi9Cu9 ans ZnAl4Cu using squeeze casting. The preforms were sintered thermically without the use of bonding agents. Using the combination of different sintering steps syntactic foams with locally different densities could be produced. The mechanical properties of the foams were tested indicating a high compression strength of the foams and a very good compression energy absorption. Furthermore, corrosion behaviour and behaviour at higher temperatures were investigated.     

RF antenna analysis with the ICANT code

The ICANT code computes self-consistently the surface current distribution on a 3D antenna model radiating in a plasma or vacuum and has been used to analyze the coupling properties of various antenna models. In this work it is used to assess near-fields generated by different versions of the TCABR (Tokamak Chauffage Alfvén wave heating experiment in Brazil) antenna as well as coupling properties of the TEXTOR tokamak in Forshungszentrum Jülich. Two different strap models planned for the TCABR antenna are shown to be practically equivalent in terms of maximum electric field. Textor coupling calculations are close to experimental values.