Anomalies of electrical properties of Sm-cuprate oxides substituted with yttrium and iron oxides at low temperatures

Samples of Sm_2-xR_xCuO₄ (R=Y and Fe), for x=0.0 and 0.05, were prepared by standard solid-state reactions. The lattice parameters of the single-phase cuprates increased for the altered samples. The samples were studied by differential scanning calorimetry, scanning electron microscopy, electrical resistivity, and thermoelectric power measurements. The effect of substitution was found to increase compound stability, decrease the electrical resistivity, and change the sign of the thermoelectric power. The anisotropy field due to apical oxygen in the unaltered sample was not found.     

Free convection in inclined air layers heated from above

An experimental investigation of steady-state natural convection heat transfer was carried out in finite rectangular air layers heated from above. Two different aspect ratios, namely A = 20 and 80, and perfectly conducting boundary conditions on the end walls were used. The angle of inclination was varied from Φ = 0 (heated from below) to Φ = 180° (heated from above). A total of 226 test points were taken for heat transfer measurements in air layers heated from above at four different orientations in the range 120 ? Φ ? 180° for Rayleigh numbers between 10² and 2 × 10⁶. Additional test points have been carried out to show the effect of the angle of tilt in the range O ? Φ ? 180° on the average Nusselt number for fixed values of the Rayleigh number. Local measurements of the Nusselt number over discrete portions of the air layer are reported to show the Nusselt number distribution over different flow regimes.     

Effect of heat treatment on the Inhibition of the acidic corrosion of aluminum alloy

The effect of heat treatment on the inhibition of acid corrosion of duralumin has been studied using gasometry, mass loss measurements and potentiodynamic technique. All the data reveal that the duralumin generally developed good corrosion resistance after heat treatment and the corrosion rate ranked as follows: Non treated > Naturally aged > quenched. This improvement in the corrosion resistance was attributed to the structural homogeneity of the heat-treated alloys. The presence of some selected aryl and alkyl triazoline derivatives at the thershold concentration of 5 × 10^?3 M indicate that these compounds retard the corrosion rate of duralumin and the extend of inhibition depends on the molecular structure of the inhibitors. Polarization curves show that the triazoline compounds act as mixed-type inhibitors affecting both the cathodic and anodic process. Moreover, there is no noticeable difference in the degree by which the triazoline derivatives inhibit the corrosion of pure aluminium and heat treated duralumin alloy.     

A generalized “max-min” sample for surrogate update

The preliminary Multidisciplinary Design and Optimisation of a flexible wing aerofoil apropos a small Unmanned Air Vehicle is performed using a multifidelity model-based strategy. Both the passively adaptive structure and the shape of the flexible wing aerofoil are optimised for best aerodynamic performance under aero-structural constraints, within a coupled aeroelastic formulation. A typical flight mission for surveillance purposes is considered and includes the potential occurrence of wind gusts. A metamodel for the high-fidelity objective function and each of the constraints is built, based on a tuned low-fidelity one, in order to improve the efficiency of the optimisation process. Both metamodels are based on solutions of the aeroelastic equations for a flexible aerofoil but employ different levels of complexity and computational cost for modelling aerodynamics and structural dynamics within a modal approach. The high-fidelity model employs nonlinear Computational Fluid Dynamics coupled with a full set of structural modes, whereas the low-fidelity one employs linear thin aerofoil theory coupled with a reduced set of structural modes. The low-fidelity responses are then corrected according to few high-fidelity responses, as prescribed by an appropriate Design of Experiment, by means of a suitable tuning technique. A standard Genetic Algorithm is hence utilised to find the global optimum, showing that a flexible aerofoil is characterised by higher aerodynamic efficiency than its rigid counterpart. Wing weight reduction is also accomplished when a Multiobjective Genetic Algorithm is adopted.     

Probing Binding and Cellular Activity of Pyrrolidinone and Piperidinone Small Molecules Targeting the Urokinase Receptor

The urokinase receptor (uPAR) is a cell‐surface protein that is part of an intricate web of transient and tight protein interactions that promote cancer cell invasion and metastasis. Here, we evaluate the binding and biological activity of a new class of pyrrolidinone and piperidinone compounds, along with derivatives of previously‐identified pyrazole and propylamine compounds. Competition assays revealed that the compounds displace a fluorescently labeled peptide (AE147‐FAM) with inhibition constant (K_i) values ranging from 6 to 63 μM . Structure‐based computational pharmacophore analysis followed by extensive explicit‐solvent molecular dynamics (MD) simulations and free energy calculations suggested the pyrazole‐based and piperidinone‐based compounds adopt different binding modes, despite their similar two‐dimensional structures. In cells, pyrazole‐based compounds showed significant inhibition of breast adenocarcinoma (MDA‐MB‐231) and pancreatic ductal adenocarcinoma (PDAC) cell proliferation, but piperidinone‐containing compounds exhibited no cytotoxicity even at concentrations of 100 μM . One pyrazole‐based compound impaired MDA‐MB‐231 invasion, adhesion, and migration in a concentration‐dependent manner, while the piperidinone inhibited only invasion. The pyrazole derivative inhibited matrix metalloprotease‐9 (gelatinase) activity in a concentration‐dependent manner, while the piperidinone showed no effect suggesting different mechanisms for inhibition of cell invasion. Signaling studies further highlighted these differences, showing that pyrazole compounds completely inhibited ERK phosphorylation and impaired HIF1α and NF‐κB signaling, while pyrrolidinones and piperidinones had no effect. Annexin V staining suggested that the effect of the pyrazole‐based compound on proliferation was due to cell killing through an apoptotic mechanism. The compounds identified represent valuable leads in the design of further derivatives with higher affinities and potential probes to unravel the protein–protein interactions of uPAR.     

Eulerian–Lagrangian Simulation and Experimental Validation of Pneumatic Conveying Dryer

This paper explores numerical and experimental studies on the performance of a pneumatic conveying dryer. The four-way coupling Eulerian–Lagrangian approach is utilized in the numerical study and the experimental study is carried out in a pilot-scale vertical pneumatic conveying dryer of diameter 8.1 cm and 4.5 m length. The effects of Reynolds number, particle size, solid mass flow rate, and inlet gas temperature on the dryer performance are investigated. It is found that the present model predictions agree well with the experimental data. Generally, it is concluded that the drying rate increases as the Reynolds number increases, while increasing the particle size or the solid mass flow rate decreases the drying rate.     

Experimental Investigation of Newly Synthesized Gemini Cationic Surfactants as Corrosion Inhibitors of Mild Steel in 1.0 M HCl

Three Gemini cationic surfactants named N¹,N¹,N³,N³-tetramethyl-N¹,N³-bis(3-octanamidopropyl) propane-1,3-diaminium bromide (C8-S3-C8), N¹,N¹,N³,N³-tetramethyl-N¹,N³-bis(3-dodecanamidopropyl) propane-1,3-diaminium bromide (C12-S3-C12) and N¹,N¹,N³,N³-tetramethyl-N¹,N³-bis(3-hexadecanamidopropyl) propane-1,3-diaminium bromide (C16-S3-C16) were evaluated as corrosion inhibitors for mild steel in 1.0 M HCl. The corrosion rate of mild steel in 1.0 M HCl at three different temperatures 25, 45 and 60oC was investigated gravimetrically. The corrosion rate of mild steel was confirmed electrically at 25oC. The corrosion inhibition efficiency directly proportionally with the hydrophobic chain length of inhibitors. The inhibition efficiency exhibit a positive trend with raising the solution temperatures. The potentiostatic polarization study revealed that the tested gemini cationic surfactants act as mixed type inhibitors with predominant control of cathodic reaction. The Villamil isotherm provide the best describing of the adsorption process on the selected steel in 1.0 M HCl. The adsorption of the tested inhibitors on the steel surface is a mixture of chemical and physical adsorption.     

A generalized multiclass histogram thresholding approach based on mixture modelling

This paper presents a new approach to multi-class thresholding-based segmentation. It considerably improves existing thresholding methods by efficiently modeling non-Gaussian and multi-modal class-conditional distributions using mixtures of generalized Gaussian distributions (MoGG). The proposed approach seamlessly: (1) extends the standard Otsu's method to arbitrary numbers of thresholds and (2) extends the Kittler and Illingworth minimum error thresholding to non-Gaussian and multi-modal class-conditional data. MoGGs enable efficient representation of heavy-tailed data and multi-modal histograms with flat or sharply shaped peaks. Experiments on synthetic data and real-world image segmentation show the performance of the proposed approach with comparison to recent state-of-the-art techniques.     

Construction and Testing of an Innovative Concrete Bridge Deck Totally Reinforced with Glass FRP Bars: Val-Alain Bridge on Highway 20 East

The Val-Alain Bridge, located in the Municipality of Val-Alain on Highway 20 East, crosses over Henri River in Québec, Canada. The bridge is a slab-on-girder type with a skew angle of 20° over a single span of 49.89?m and a total width of 12.57?m. The bridge has four simply supported steel girders spaced at 3,145?mm. The deck slab is a 225-mm-thick concrete slab, with semi-integral abutments, continuous over the steel girders with an overhang of 1,570?mm on each side. The concrete deck slab and the bridge barriers were reinforced with glass fiber reinforced polymer (GFRP) reinforcing bars utilizing high-performance concrete. The Val-Alain Bridge is the Canada’s first concrete bridge deck totally reinforced with GFRP reinforcing bars. Using such nonmetallic reinforcement in combination with high-performance concrete leads to an expected service life of more than 75?years. The bridge is well instrumented with electrical resistance strain gauges and fiber-optic sensors at critical locations to record internal strain data. Also, the bridge was tested for service performance using calibrated truckloads. Design concepts, construction details, and results of the first series of live load field tests are presented.