A dynamic fuzzy cognitive map applied to chemical process supervision

This work develops an intelligent tool based on fuzzy cognitive maps to supervisory process control. Fuzzy cognitive maps are a neuro-fuzzy methodology that can accurate model complexly system using a causal-effect fuzzy reasoning. In the proposed approach, new types of concept and relation, not restricted to cause–effect ones, are added to the model resulting in a dynamic fuzzy cognitive map (D-FCM). In this sense, a supervisory system is developed in order to control a fermentation process. This process has a non-linear behavior and presents several problems, such as non-minimum phase and large accommodation time. The supervisor goal is to operate the process in normal and critical conditions. The expert knowledge about the process behavior in both conditions is used to build the D-FCM supervisor. Simulation results are presented in order to validate the proposed intelligent supervisor.     

Bdellovibrio bacteriovorus to control Escherichia coli on meat matrices

Bdellovibrio bacteriovorus is a predator micro-organism towards other Gram-negative bacteria. We tested B. bacteriovorus to control Escherichia coli growth on chicken slices and canned beef. Moreover, we analysed B. bacteriovorus's lytic ability on eight toxigenic or multidrug-resistant E. coli strains. In chicken slices, the predator induced the highest prey reduction (4.3 log) respect to control at 6 h. In canned beef, the predator induced the highest prey reduction (2.1 log) respect to control at 6 h. Moreover, B. bacteriovorus showed lytic ability towards all tested E. coli strains. B. bacteriovorus could control E. coli and other pathogenic and spoilage bacteria in those meat-based foods that have a shelf life <10 days. It could integrate modified atmosphere packaging (MAP) to prolong the shelf life and improve the safety of pre-packed fresh meat, meat preparations and meat products. In future applications on meat-based foods, B. bacteriovorus could also minimise the use of additives.     

Antagonism to noradrenaline-induced lethality in rats is related to affinity for the alpha1A-adrenoceptor subtype

The potency of several alpha1-adrenoceptor antagonists in preventing the noradrenaline-induced lethality in conscious rats, their binding affinity for the native alpha1A- and alpha1B-adrenoceptors, the recombinant animal alpha1a-, alpha1b- and alpha1d-adrenoceptor subtypes, as well as their functional affinity for the alpha1L-adrenoceptor subtype were evaluated. The potency of the tested compounds as antagonists of noradrenaline-induced lethality was correlated with the affinity for the alpha1A- (and alpha1a-) adrenoceptor subtype, but not with the affinity for the other subtypes. On the contrary, the hypotensive effects of the compounds, assessed in anesthetized rats, were not clearly related with the affinity for any of the alpha1-subtypes. These results suggest that the alpha1A-subtype plays a determining role in preventing lethality induced by noradrenaline in the rats, and that this activity is unrelated to the hypotensive effect of the compounds, which cannot be clearly correlated with affinity for a particular alpha1-adrenoceptor subtype.     

Low-energy ion--surface reactions of pyrazine with two classes of self-assembled monolayers: influence of alkyl chain orientation

Collisions of pyrazine with two classes of self-assembled monolayer (SAM) films are employed to determine whether surface confinement and the resulting alkyl chain orientation, influences low-energy ion-surface reactions. SAM films formed from n-alkanethiols (CH3(CH2)n-S-Au, n = 14-17) and 4-(4-alkoxyphenylbenzenethiols (4-(4-CH3(CH2)mOC6H4)-C6H4-S-Au, m = 14-17) chemisorbed onto Au (111) substrates are known to exhibit a chain-length-dependent odd-even effect that places the terminal C-C bond into different orientations. Ion-surface collisions (20 eV) of pyrazine molecular ion (M = m/z 80) with these surfaces yield reaction product ions corresponding to the addition of hydrogen atoms ([M + H]+ = m/z 81) and methyl groups ([M + CH3]+ = m/z 95) from the surface to the probe ion. Differences in the relative abundance of the reaction product ions are measured as a function of chain length for both classes of SAM film. SAM films with odd chain lengths (n, m = 14 and 16) have a consistently higher abundance of H addition product ions than SAM films with even chain lengths (n, m = 15 and 17). Alternating reactivity is also observed for the addition of CH3, with methyl addition occurring more readily on even-chain-length films. The variations are consistent with the well-characterized orientation differences known to exist for films of this type. Specifically, odd-chain-length films are oriented such that the last C-C bond is more parallel to the plane of the surface than it is for even-chain-length films. The critical element of the parallel orientation is that it leaves, on average, one hydrogen atom on the terminal methyl and both hydrogen atoms on the first underlying methylene in more reactive positions compared to even chain lengths. Conversely, the trend in the relative abundance of CH3 addition indicates that the orientation produced by an even-chain-length film, with the last C-C bond more perpendicular to the surface, allows the probe ion better access to the methyl carbon. Reflection absorption IR spectroscopy (RAIRS) data independently confirm the orientational disposition of the films. The RAIRS data show that the odd-even effect is less dramatic for the n-alkanethiols when compared to 4-(4-alkoxyphenyl)benzenethiols. A smaller difference in ion-surface reactivity is measured for n-alkanethiols, demonstrating that ion-surface reactions can distinguish subtle differences in average orientation. In short, we report that the extent of ion-surface reactions of pyrazine ion with two classes of SAM films is directed by the spatial orientation of the surface-confined species that participate in the reaction.     

Defining requirements for an Augmented Reality system to overcome the challenges of creating and using design representations in co-design sessions

ABSTRACT

Within co-design sessions involving designers and non-designers, the type and characteristics of the design representations employed is known to impact the performance of such sessions in terms of idea generation, idea evaluation and communication. This study captures the challenges practitioners face in creating and using design representations for co-design sessions and goes on to investigate the potential of Spatial Augmented Reality (SAR) to overcome those challenges. The advantages of SAR in this application are that, multiple concepts can be represented using one physical model, concepts can be modified live during the session, and additional equipment (such as head mounted displays or handheld devices) is not required, thus eliminating any possible interference with the natural interactions between participants. Interviews with design practitioners and trials with a prototype SAR system are used to identify the key challenges faced by practitioners in their current use of design representations, and to capture the technology requirements for a SAR system for use in co-design sessions. These findings can inform the work of technology developers and researchers working on systems to support co-design sessions.