State of the art about dissimilar metal friction stir welding

Friction stir welding is a rather recent welding process (patented in 1991 by Thomas et al., ‘Improvements to friction welding’ UK patent application no. 9125978.8, US Patent 5460317, 1995) that has shown great potential for welding dissimilar materials even of different metallic nature, e.g. Al to steel, Mg to steel, Al to Ti, Mg to Ti, Al to Cu, Al to Mg. This review presents the specific microstructural features and mechanical properties, in particular tensile strength, of such welds. A focus will be on the material flow and welding defects, on the intermetallic compounds, on constitutional liquation, on particularities related to dissimilar lap welding and finally on process modifications to improve dissimilar friction stir weldability.     

Discriminating natal origin of spawning adult sea lamprey (Petromyzon marinus) in Lake Champlain using statolith elemental signatures

Sea lamprey (Petromyzon marinus) is a nuisance species in the Great Lakes and Lake Champlain. Information about tributary contributions to the spawning adult phase is critical for appropriate allocation of efforts to control this species. We examined the accuracy of statolith elemental composition to identify the natal origin (i.e., individual rivers or clusters of rivers) of 33 known-origin adults from the Lake Champlain basin. To do so, we first established natal origin chemical signatures using the statoliths of 238 larvae from the same basin. Using laser-ablation inductively coupled plasma mass spectrometry, the 238 larvae originating from 12 streams and one delta were discriminated with a classification accuracy of 57% (range: 25–80%) and 70% (range: 29–80%) when individual streams and groups of streams were considered respectively, highlighting the potential of statolith microchemistry to identify natal origins. However, the assignment of natal origin for adults was overwhelmingly incorrect. Using a maximum likelihood procedure, 88% of the adults were assigned to a cluster of three streams and one delta, while only 3% of these individuals were known to originate from this particular cluster. More research is required to understand the low classification accuracy of sea lamprey adults and validate the use of statolith microchemistry to identify sea lamprey natal origin.     

Polymer Films Composed of Surface‐Bound Nanofilaments with a High Aspect Ratio,Molecularly Imprinted with Small Molecules and Proteins

Hierarchically nanostructured materials that combine two or more levels of structuring and that exhibit a combination of useful features have gained considerable interest over recent years. Here, the generation of surface‐bound nanofilaments with a high aspect ratio by nanomolding on a nanoporous template surface is described. The filaments, at the same time, carry molecularly imprinted binding sites. The dye fluorescein and the protein myoglobin are used as model templates for imprinting. The surfaces exhibit specific binding as revealed by fluorescence microscopy. The wetting properties of the surfaces depend on the dimensions of the nanofilaments and on the nature of the polymer. It is believed that these materials can potentially be useful for applications in biosensors and biochips.     

Comparative proteome profiling of MCF10A and 184A1 human breast epithelial cells emphasized involvement of CDK4 and cyclin D3 in cell proliferation

Acquiring high proliferation rate is crucial for carcinogenic transformation of cells. We report here proteome profiling of human breast epithelial cells with low (184A1) and high (MCF10A) proliferation rates. We identified 183 proteins in 184A1 and 318 proteins in MCF10A cells. These datasets provide the most comprehensive proteome annotations of 184A1 and MCF10A cells. Proteins were taken for identification from 2-D gels in a systematic and unbiased way. Functional clustering of the identified proteins showed similarities in distribution of proteins to the same functional domains, indicating similarities in proteomes of 184A1 and MCF10A cells. Among observed differences in protein expression, we validated correlation of expression of endogenous cyclin-dependent kinase 4 (CDK4), cyclin D3, cdc25B, and p38γ with cell proliferation. Furthermore, down-regulation of CDK4 and cyclin D3 with specific siRNA inhibited cell proliferation, which emphasized the role of CDK4 and cyclin D3 in enhancement of cell proliferation rate of human breast epithelial cells.     

Modeling the Shape of the Scene: A Holistic Representation of the Spatial Envelope

In this paper, we propose a computational model of the recognition of real world scenes that bypasses the segmentation and the processing of individual objects or regions. The procedure is based on a very low dimensional representation of the scene, that we term the Spatial Envelope. We propose a set of perceptual dimensions (naturalness, openness, roughness, expansion, ruggedness) that represent the dominant spatial structure of a scene. Then, we show that these dimensions may be reliably estimated using spectral and coarsely localized information. The model generates a multidimensional space in which scenes sharing membership in semantic categories (e.g., streets, highways, coasts) are projected closed together. The performance of the spatial envelope model shows that specific information about object shape or identity is not a requirement for scene categorization and that modeling a holistic representation of the scene informs about its probable semantic category.     

Gaming on the move: urban experience as a new paradigm for mobile pervasive game design

In this paper, we describe a pervasive treasure hunting game: “Team exploration” based on the Transhumance mobile ad-hoc network platform. The testers of this game came up with innovative suggestions that combined the technical features of the platform with their urban experience. They pointed to specific aspects of urban mobility that influence pervasive game design and contribute to the user’s pleasure. These tests show that the notion of space (geometrical organization) is not enough to characterize and organize pervasive games and that four main anthropological features have to be taken into consideration: the concrete city (physical organization), the imaginary city (narratives), the functional city (services) and the city events. The multilayered urban experience is also defined by our schedules (including repetitive or exceptional events) and by our assessment of other users (the distance or proximity as they are felt). These diverse aspects and qualifications of urban experience provide an interesting framework for the understanding of pervasive game experimentations, as well as point to new directions in pervasive game design. Our paper advocates that further anthropological observations are part of the pervasive game design methodology.     

Modelling adaptive management of intercropping in vineyards to satisfy agronomic and environmental performances under Mediterranean climate

In the Mediterranean area, rainfed viticulture is exposed to irregular rainfall distribution. The impacts on production and environment can be mitigated by appropriate management practices like, for instance, the introduction of cover crop in the inter-rows in vineyards. This paper presents the VERDI simulation model created to study various adaptive intercrop management strategies at field scale. The purpose is to design management strategies that are responsive to the water status of the biophysical system (soil – grapevine – intercrop) and the past and current climatic conditions. VERDI realistically reproduces the dynamic interactions between the biophysical system and the decision system in varying Mediterranean rain regime. The decision system works as an interpreter of a management strategy, defined as a set of soil surface management activities (e.g. mechanical weeding of the intercrop) that are linked by temporal constraints (e.g. sequencing, synchronisation) and organisational or programmatic specifications (e.g. iteration). The adaptive capabilities of the strategies are distinguished according to the different sources of flexibility to be exploited at operational, tactical, and strategic levels. A simulation study is reported that involves more or less flexible strategies under different climate scenarios. The simulation results proved that, in case of severe drought, the most flexible strategy yields the best trade-off between agricultural production and environmental services over the years.     

Electrolytic methanogenic-methanotrophic coupling for tetrachloroethylene bioremediation: proof of concept

Coupling of methanogenic and methanotrophic catabolisms was performed in a single-stage technology equipped with a water electrolysis cell placed in the effluent recirculation loop. The electrolysis-generated hydrogen served as an electron donor for both bicarbonate reduction into CH4 and reductive dechlorination, while the O2 and CH4, supported the cometabolic oxidation of chlorinated intermediates left over by the tetrachloroethylene (PCE) transformation. The electrolytical methanogenic/methanotrophic coupled (eMaMoC) process was tested in a laboratory-scale setup at PCE loads ranging from 5 to 50 micromol/L(rx) x d (inlet concentrations from 4 to 11 mg/L), and at various hydraulic residence times (HRT). Degradation followed essentially a reductive dechlorination pathway from PCE to cis-1,2-dichloroethene (DCE), and an oxidative pathway from DCE to CO2. PCE reductive dechlorination to DCE was consistently over 98% while a maximum oxidative DCE mineralization of 89% was obtained at a load of 4.3 micromol PCE/ L(rx) x d and an HRT of 6 days. Controlling dissolved oxygen concentrations within a relatively low range (2-3 mg/L) seemed instrumental to sustain the overall degradation capacity. Degradation kinetics were further evaluated: the apparent half-saturation constant (K(s)) had to be set relatively high (29 microM) for the simulated data to best fit the experimental ones. In spite of such kinetic limitations, the eMaMoC system, while fueled by water electrolysis, was effective in building and sustaining a functional methanogenic/methanotrophic consortium capable of significant PCE mineralization in a single-stage process. Hence, degradation standards are within reach so long as the methanotrophic DCE-oxidizing potential, including substrate affinity, are optimized and HRT accordingly adjusted.     

Analogical Cellular Structure Changes in Solid-Liquid Contacting Operations

Mass transfer characteristics are closely related to the cell structures. When cellular material comes in contact with a solution of high concentration, changes in physical properties of cellular material occurred throughout the process at a different degree depending on the process conditions and material matrix characteristics. Six possible situations, Cases I-VI, of changes in cell structure immersed in solution of high concentration are proposed. In this study, the specific influence of red beet tissue shrinkage on mass transfer in 600 g/kg sucrose solution at 25°C is discussed. The changes of cell unit and an analogical cellular structure are discussed. In the solid-liquid contacting period, the situation of volume changes of cell unit of red beet material remained in the no cell volume change (Cases I and II) condition. In most cases, the volume of extracellular space of cellular material decreased with water transfer out of tissue, then material matrix began to collapse, resulting in the changes in porosity. The porosity changes in the no cell volume change cases (Cases I and II) were considered as special conditions without the consideration of cellular material tissue shrinkage. The tissue structure shrinkage cases (Cases III-VI) were considered to occur more often when a fresh, soft cellular material tissue such as fruits and vegetables was contacted with osmotic solution of high concentration.     

Geodynamic and seismic constraints on the thermochemical structure and dynamics of convection in the deep mantle

We revisit a recent study by Forte & Mitrovica in which global geophysical observables associated with mantle convection were inverted and the existence of a strong increase in viscosity near a depth of 2000 km was inferred. Employing mineral-physics data and theory we also showed that, although there are chemical anomalies in the lowermost mantle, they are unable to inhibit the dominant thermal buoyancy of the deep-mantle mega-plumes below Africa and the Pacific Ocean. New Monte Carlo simulations are employed to explore the impact of uncertainties in current mineral-physics constraints on inferences of deep-mantle thermochemical structure. To explore the impact of the high-viscosity peak at a depth of 2000 km on the evolution of lower-mantle structure, we carried out time-dependent convection simulations. The latter show that the stability and longevity of the dominant long-wavelength heterogeneity in the lowermost mantle are controlled by this viscosity peak.