Modelling the effects of waste components on cement hydration

Ordinary Portland Cement (OPC) is often used for the Solidification/Stabilization (S/S) of waste containing heavy metals and salts. These waste componenents will precipitate in the form of insoluble compounds onto unreacted cement clinker grains preventing further hydration. In this study the long term effects of the presence of contaminants in solidified waste is examined by numerically simulating cement hydration after precipitation of metal salts on the surface of cement grains. A cement hydration model was extended in order to describe porewater composition and the effects of coating. Calculations were made and the strength development predicted by the model was found to agree qualitatively with experimental results found in literature. The complete model is useful in predicting the strength and leaching resistance of solidified products and developing solidification recipes based on cement

Stimulating The Use Of Secondary Materials In The Construction Industry: The Role Of Certification\ud

Introduction of secondary materials in the construction industry is quite difficult and has not always been successful, even when they satisfy all necessary product demands and environmental (leaching) conditions. Besides the financial and commercial aspects the main problem is convincing the user or customer that the secondary material is a safe and reliable alternative for primary materials. The best way to deal with this problem is by certification of the secondary material. Optimal results can be expected when authorities and both suppliers and users of the new type of material closely collaborate. This can be achieved by mutual consulting in regard to technical aspects and their demands concerning the product. Collaboration between suppliers enables joint investments in order to obtain certification and to enhance the knowledge about their product. This collaboration will also stimulate the consideration that the supplier is a good and reliable trading partner for the use

Chemical reaction of fly ash

In a previous paper, Brouwers and Van Eijk presented a theoretical study on the dissolution (reaction) of pulverised powder coal fly ash. This fly ash was modelled as hollow spheres, and a shrinking core model was derived for these hollow spheres that contain two regions (an outer hull and an inner region). The obtained analytical equations were applied to the dissolution experiments by Pietersen, yielding reaction rates at various temperatures and pH for two class F fly ashes. Based on the observed trends, in the present paper a reaction mechanism is proposed for the glass phase which accounts for the oxide composition of the fly ash (and that is applicable to slags as well). Finally, using the reaction product, the following thermodynamic properties of the studied fly ashes are derived: the free energy, enthalpy and entropy of reaction. The values obtained are in line with those of known substances: silica and an aluminosilicate (2SiO2.Al2O3)

Conceptual Mismatches and Repair in Human-Computer Interaction

We present a computational framework for the generation of elementary speech acts to establish conceptual alignment between a computer system and its user. We clearly distinguish between two phases of the alignment process: message interpretation and message generation. In the interpretation phase, presuppositions are extracted from the user’s message and compared with the system’s ontology. Subsequently, in the generation phase, an adequate feedback message is produced in order to resolve detected discrepancies. We provide a conversational strategy that is based upon Gricean implicatures and a distinction between three types of beliefs: private beliefs about the domain of discourse, beliefs about the beliefs of the other and beliefs about the shared beliefs

Isoforms of transferrin in psoriasis patients abusing alcohol

The different isoforms of transferrin have been quantified by isoelectric focusing in the sera of psoriasis patients with and without a history of abusing alcohol. In both male and female psoriasis subjects abusing alcohol, there were significant increases in the 2-sialylated forms by comparison to the control subjects. Psoriasis patients who had no evidence of alcohol abuse had similar profile for the isoforms of transferrin to that of the controls. Other groups of patients with alcohol-induced tissue damage, i.e. liver, brain or muscle, used as positive controls, similarly showed significant increases in the 2-sialylated forms, by comparison to controls. These results substantiate the current use of carbohydrate-deficient transferrin as a sensitive marker of alcohol abuse, particularly in subjects not drinking in excess of 60 g of ethanol/day but showing alcohol-related psoriasis

Adipocytes harbor a glucosylceramide biosynthesis pathway involved in iNKT cell activation

Background: Natural killer T (NKT) cells in adipose tissue (AT) contribute to whole body energy homeostasis. Results: Inhibition of the glucosylceramide synthesis in adipocytes impairs iNKT cell activity. Conclusion: Glucosylceramide biosynthesis pathway is important for endogenous lipid antigen activation of iNKT cells in adipocytes.Significance: Unraveling adipocyte-iNKT cell communication may help to fight obesity-induced AT dysfunction.Overproduction and/or accumulation of ceramide and ceramide metabolites, including glucosylceramides, can lead to insulin resistance. However, glucosylceramides also fulfill important physiological functions. They are presented by antigen presenting cells (APC) as endogenous lipid antigens via CD1d to activate a unique lymphocyte subspecies, the CD1d-restricted invariant (i) natural killer T (NKT) cells. Recently, adipocytes have emerged as lipid APC that can activate adipose tissue-resident iNKT cells and thereby contribute to whole body energy homeostasis. Here we investigate the role of the glucosylceramide biosynthesis pathway in the activation of iNKT cells by adipocytes.UDP-glucose ceramide glucosyltransferase (Ugcg), the first rate limiting step in the glucosylceramide biosynthesis pathway, was inhibited via chemical compounds and shRNA knockdown in vivo and in vitro. beta-1,4-Galactosyltransferase (B4Galt) 5 and 6, enzymes that convert glucosylceramides into potentially inactive lactosylceramides, were subjected to shRNA knock down. Subsequently, (pre)adipocyte cell lines were tested in co-culture experiments with iNKT cells (IFN gamma and 114 secretion).Inhibition of Ugcg activity shows that it regulates presentation of a considerable fraction of lipid self-antigens in adipocytes. Furthermore, reduced expression levels of either B4Galt5 or -6, indicate that B4Galt5 is dominant in the production of cellular lactosylceramides, but that inhibition of either enzyme results in increased iNKT cell activation. Additionally, in vivo inhibition of Ugcg by the aminosugar AMP-DNM results in decreased iNKT cell effector function in adipose tissue.Inhibition of endogenous glucosylceramide production results in decreased iNKT cells activity and cytokine production, underscoring the role of this biosynthetic pathway in lipid self-antigen presentation by adipocytes