Redundancy relations and robust failure detection

All failure detection methods are based on the use of redundancy, that is on (possible dynamic) relations among the measured variables. Consequently the robustness of the failure detection process depends to a great degree on the reliability of the redundancy relations given the inevitable presence of model uncertainties. The problem of determining redundancy relations which are optimally robust in a sense which includes the major issues of importance in practical failure detection is addressed. A significant amount of intuition concerning the geometry of robust failure detection is provided

Mass fluctuation kinetics: analysis and computation of equilibria and local dynamics

The mass fluctuation kinetics (MFK) model is a set of coupled ordinary differential equations approximating the time evolution of means and covariances of species concentrations in chemical reaction networks. It generalises classical mass action kinetics (MAK), in which fluctuations around the mean are ignored. MFK may be used to approximate stochasticity in system trajectories when stochastic simulation methods are prohibitively expensive computationally. This study presents a set of tools to aid in the analysis of systems within the MFK framework. A closed-form expression for the MFK Jacobian matrix is derived. This expression facilitates the computation of MFK equilibria and the characterisation of the dynamics of small deviations from the equilibria (i.e. local dynamics). Software developed in MATLAB to analyse systems within the MFK framework is also presented. The authors outline a homotopy continuation method that employs the Jacobian for bifurcation analysis, that is, to generate a locus of steady-state Jacobian eigenvalues corresponding to changing a chosen MFK parameter such as system volume or a rate constant. This method is applied to study the effect of small-volume stochasticity on local dynamics at equilibria in a pair of example systems, namely the formation and dissociation of an enzyme-substrate complex and a genetic oscillator. For both systems, this study reveals volume regimes where MFK provides a quantitatively and/or qualitatively correct description of system behaviour, and regimes where the MFK approximation is inaccurate. Moreover, our analysis provides evidence that decreasing volume from the MAK regime (infinite volume) has a destabilising effect on system dynamics

Food waste opportunities within the food wholesale and retail sectors

The aim of this research project is to provide the NSW Environment Protection Authority (NSW EPA) with a better understanding of the opportunities and barriers to reduce the amount of food waste going to landfill from the wholesale, logistics and retail sector. This report presents the research findings and provides a series of recommendations as to how NSW EPA can most effectively engage with these sectors within the food supply chain to maximise performance while minimising disruption and costs

Alternative mechanisms of structuring biomembranes: Self-assembly vs. self-organization

We study two mechanisms for the formation of protein patterns near membranes of living cells by mathematical modelling. Self-assembly of protein domains by electrostatic lipid-protein interactions is contrasted with self-organization due to a nonequilibrium biochemical reaction cycle of proteins near the membrane. While both processes lead eventually to quite similar patterns, their evolution occurs on very different length and time scales. Self-assembly produces periodic protein patterns on a spatial scale below 0.1 micron in a few seconds followed by extremely slow coarsening, whereas self-organization results in a pattern wavelength comparable to the typical cell size of 100 micron within a few minutes suggesting different biological functions for the two processes.Comment: 4 pages, 5 figure

Successful Design Briefs are not all Black and White

The task of a designer is to project the future into the present by articulating a possible outcome to an existing condition. This paper will examine the outcomes of these projections, through a comparative analysis of a controlled group of design students designing products and spaces for birthing units. Linked to a larger interdisciplinary study on the impact of birthing unit design on communication between birthing mothers, staff and family/support members, this research provided an opportunity to explore practice-led research together with case studies and literature reviews of current conditions. With the educational design directive to explore conceptual ideas, the first of two groups of students were presented with a standard written brief for the redesign of birthing units. They were asked to focus on either: a product, space, or combination of product and spatial design to address the needs of a birthing unit. A second group were given the same problem but were also provided with detailed video ethnographic information to supplement the written brief. The aim of this paper is to critically reflect upon the differences in the outcomes of a traditional form of design brief with that of the brief using video ethnography. By examination of all the factors affecting the complex context of birthing units, and the mode of communication of a project brief, this paper will present its findings that will facilitate future design briefs for birthing units to lead to more appropriate outcomes. In doing so the issue of whether or not a black and white text document is sufficient for improving the design of birthing units

Infrared spectra and thermal decompositions of metal acetates and dicarboxylates

The infrared spectra of rare earth acetates have been studied to examine the metal-acetate bonding. The thermal decomposition of rare earth acetates as well as lead and copper acetates have been investigated in detail by employing thermogravimetric analysis and differential thermal analysis. Thermal decomposition of calcium dicarboxylates (malonate to sebacate) have been studied employing t.g.a. and d.t.a. Infrared spectra of the dicarboxylates have also been studied. Preliminary results on the products of decomposition of dicarboxylates have been reported

Ventilator-associated Acinetobacter baumannii pneumonia

We report an outbreak of ventilator-associated pneumonia caused by carbapenem-resistant Acinetobacter baumannii in 6 infants with acute lower respiratory tract infection. Non-bronchoscopic bronchoalveolar lavage isolated A. baumannii in all these infants. Environmental microbiological survey of the Pediatric intensive care unit and pediatric wards identified oxygen humidifying chambers as the source of Acinetobacter. Practices of cleaning and changing of the humidifiers were reviewed and the outbreak was controlled with new recommendations

CD14-dependent lipopolysaccharide-induced β-defensin-2 expression in human tracheobronchial epithelium

The induction of host antimicrobial molecules following binding of pathogen components to pattern recognition receptors such as CD14 and the Toll-like receptors (TLRs) is a key feature of innate immunity. The human airway epithelium is an important environmental interface, but LPS recognition pathways have not been determined. We hypothesized that LPS would trigger β-defensin (hBD2) mRNA in human tracheobronchial epithelial (hTBE) cells through a CD14-dependent mechanism, ultimately activating NF-κB. An average 3-fold increase in hBD2 mRNA occurs 24 h after LPS challenge of hTBE cells. For the first time, we demonstrate the presence of CD14 mRNA and cell surface protein in hTBE cells and show that CD14 neutralization abolishes LPS induction of hBD2 mRNA. Furthermore, we demonstrate TLR mRNA in hTBE cells and NF-κB activation following LPS. Thus, LPS induction of hBD2 in hTBE cells requires CD14, which may complex with a TLR to ultimately activate NF-κB

Mixed enrichment core design for the NC State University PULSTAR Reactor

The North Carolina State University PULSTAR Reactor license was renewed for an additional 20 years of operation on April 30, 1997. The relicensing period added additional years to the facility operating time through the end of the second license period, increasing the excess reactivity needs as projected in 1988. In 1995, the Nuclear Reactor Program developed a strategic plan that addressed the future maintenance, development, and utilization of the facility. Goals resulting from this plan included increased academic utilization of the facility in accordance with its role as a university research facility, and increased industrial service use in accordance with the mission of a land grant university. The strategic plan was accepted, and it is the intent of the College of Engineering to operate the PULSTAR Reactor as a going concern through at least the end of the current license period. In order to reach the next relicensing review without prejudice due to low excess reactivity, it is desired to maintain sufficient excess reactivity so that, if relicensed again, the facility could continue to operate without affecting users until new fuel assistance was provided. During the NC State University license renewal, the operation of the PULSTAR Reactor at the State University of New York at Buffalo (SUNY Buffalo) was terminated. At that time, the SUNY Buffalo facility had about 240 unused PULSTAR Reactor fuel pins with 6% enrichment. The objective of the work reported here was to develop a mixed enrichment core design for the NC State University PULSTAR reactor which would: (1) demonstrate that 6% enriched SUNY buffalo fuel could be used in the NC State University PULSTAR Reactor within the existing technical specification safety limits for core physics parameters; (2) show that use of this fuel could permit operating the NC State University PULSTAR Reactor to 2017 with increased utilization; and (3) assure that the decision whether or not to relicense the facility would not be prejudiced by reduced operations due to low excess reactivity