Structure investigation of nano-FeO(OH) modified clinoptilolite tuff for antimony removal

Biomimetic sol-gel synthesis was used to prepare new FeO(OH) zeolite (clinoptilolite tuff) adsorbent effective for antimony removal. The product was compared with other on the market accessible natural or commercial adsorption materials like granulated ferric hydroxide GEH, powder of zero valent iron (ZVI)- nanofer and the new synthesized oxi(hydr)oxide FeO(OH) and characterized by XRD, XPS, Raman, FT IR, TG, DTA, DTG, TEM and SEM techniques. Based upon the SEM analysis, the oxidized nanofer sample revealed the existence of hematite and goethite and morphology of FeO(OH) dopant confirmed the presence of ferrihydrite, in less extent also magnetite and hematite. Recorded exothermic maxima on DTA curves for powdered FeO(OH) zeolite at 460 °C and for pure component FeO(OH) at 560 °C indicated an 100 °C shifted exothermic effect, which characterized strong chemical interaction of FeO(OH) with zeolite structure. Based upon the XPS analyses, also the difference between Fe species in the raw and FeO(OH) doped zeolite was found in increasing Si/Al ratio, however only at the surface below app. 5 nm, measured as 3.94 for raw and 5.38 for sample treated with alkalic solution. The plotting of adsorption isotherms in the system studied clearly showed the increasing uptake capacity of the adsorbents towards antimony with the increased S(BET) data (GEH ˃FeO(OH)˃FeO(OH) zeolite˃nanofer)

A Study of the PDGF Signaling Pathway with PRISM

In this paper, we apply the probabilistic model checker PRISM to the analysis of a biological system -- the Platelet-Derived Growth Factor (PDGF) signaling pathway, demonstrating in detail how this pathway can be analyzed in PRISM. We show that quantitative verification can yield a better understanding of the PDGF signaling pathway.Comment: In Proceedings CompMod 2011, arXiv:1109.104

Macro-defect-free materials with controlled moisture resistance

The latest research on the reactivity toward cross-linking of inorganic matrixes formed by cement-based materials, and the associated grafting at the nanoscopic and atomic levels, is highly promising. Macro-defect-free (MDF) materials and technologies were originally comprised of high-alumina cements cross-linked to poly(vinyl alcohol/acetate) or of portland cement with poly(acrylamide). Although the high-alumina system has shown promising results and is the more efficient system, it suffers from economic disadvantages; modern efforts to identify MDF systems focus on portland cement and a variety of polymer additives. We report recent findings regarding the potential and limitations of portland cement-based MDF materials, considering aspects of the associated chemistry (at the nanoscopic and atomic levels), of the mechanism linking polymer to the surface of cement grains, and of technologically relevant attributes such as moisture resistance of the formed MDF material

Probabilistic Cost Enforcement of Security Policies

Abstract. This paper presents a formal framework for run-time enforcement mechanisms, or monitors, based on probabilistic input/output automata [3, 4], which allows for the modeling of complex and interactive systems. We associate with each trace of a monitored system (i.e., a monitor interposed between a system and an environment) a probability and a real number that represents the cost that the actions appearing on the trace incur on the monitored system. This allows us to calculate the probabilistic (expected) cost of the monitor and the monitored system, which we use to classify monitors, not only in the typical sense, e.g., as sound and transparent [17], but also at a more fine-grained level, e.g., as cost-optimal or cost-efficient. We show how a cost-optimal monitor can be built using information about cost and the probabilistic future behavior of the system and the environment, showing how deeper knowledge of a system can lead to construction of more efficient security mechanisms.