On the mass and momentum transport in the Navier–Stokes slip layer

The Navier–Stokes slip boundary conditions are considered as conditions following from the mass and momentum balances within a thin, shell-like moving boundary layer. A problem of consistency between different models, that describes the internal and external friction in a viscous fluid, is stated within the framework of a proper form of the layer momentum balance. Appropriate constitutive equations for friction forces are formulated. The common features of the Navier, Stokes, Reynolds, and Maxwell concepts of a boundary slip layer are revalorized and discussed. Different mobility mechanisms connected with the transpiration phenomena, important for flows in micro- and nanochannels, are classified as a part of equations for the external friction.     

Structural sensitivity analysis in nonlinear and transient problems using the local response function technique

The main aim of this work is the mathematical formulation, computational implementation and the application of the local version of the Response Function Method (RFM) to analyze structural design sensitivity in nonlinear structures and problems. This method is based on the Finite Element Method-based determination of the polynomial response function between design parameter and the structural state function like displacements or temperatures. One may use this numerical technique in its global version, where a single polynomial is determined for the entire computational domain or, in the case of nonlinear, transient analyses or the heterogeneous domains, in the local approach—where nodal response function are to be determined. The application of this methodology is illustrated with three examples—transient heat transfer in the homogeneous rod, the elastoplastic analysis of 2D truss as well as the eigenvibrations for a large scale 3D structure, where time, increment and eigenvalue dependent variations of the first and the second order sensitivities with respect to the physical and material parameters are computed. The first order gradients computed with the use of the RFM approach are contrasted with the finite difference computations.     

The CD200 Regulates Inflammation in Mice Independently of TNF-α Production

Inflammatory bowel disease is characterized by the infiltration of immune cells and chronic inflammation. The immune inhibitory receptor, CD200R, is involved in the downregulation of the activation of immune cells to prevent excessive inflammation. We aimed to define the role of CD200R ligand-CD200 in the experimental model of intestinal inflammation in conventionally-reared mice. Mice were given a dextran sodium sulfate solution in drinking water. Bodyweight loss was monitored daily and the disease activity index was calculated, and a histological evaluation of the colon was performed. TNF-α production was measured in the culture of small fragments of the distal colon or bone marrow-derived macrophages (BMDMs) cocultured with CD200⁺ cells. We found that Cd200^−/− mice displayed diminished severity of colitis when compared to WT mice. Inflammation significantly diminished CD200 expression in WT mice, particularly on vascular endothelial cells and immune cells. The co-culture of BMDMs with CD200⁺ cells inhibited TNF-α secretion. In vivo, acute colitis induced by DSS significantly increased TNF-α secretion in colon tissue in comparison to untreated controls. However, Cd200^−/− mice secreted a similar level of TNF-α to WT mice in vivo. CD200 regulates the severity of DSS-induced colitis in conventionally-reared mice. The presence of CD200⁺ cells decreases TNF-α production by macrophages in vitro. However, during DDS-induced intestinal inflammation secretion of TNF-α is independent of CD200 expression.     

The Potential of Al2O3–ZrO2-Based Composites,Formed via CSC Method,in Linear Infrastructure Applications Based on Their Mechanical,Thermal and Environmental performance

Metallurgical and Materials Transactions A - Ceramic-ceramic composites have been prepared using the centrifugal slip casting method (CSC). The method has so far been mainly utilized in making...     

Hole filling in 3D volumetric objects

The construction of hole filling (or hole segmentation) method for 3D volumetric images is a new challenging issue in computer science. It needs a geometrical approach since from a topological point of view 3D holes (tunnels) are not well-delimited subsets of three dimensional space. In this paper, the authors propose an original, efficient, flexible algorithm of hole filling for volumetric objects. The algorithm has been tested on artificial objects and very complicated crack propagation tomography images. The qualitative results, quantitative results and features of proposed approach are presented in the paper. According to our knowledge it is the first algorithm of hole filling for volumetric objects.     

Ionization efficiency calculations for cavity thermoionization ion source

The numerical model of a thermoemission ion source was used for source ionization efficiency calculations. The dependency of ionization efficiency on working parameters like ionizer length and extraction voltage was discussed, and a good agreement with theoretical predictions was achieved. It was shown that increasing the ionizer length does not significantly change the obtained ionization efficiency. Extraction voltages up to a few thousand of volts are sufficient to obtain reasonable efficiency.     

Finding regions of interest for cancerous masses enhanced by elimination of linear structures and considerations on detection correctness measures in mammography

Cancerous mass detection methods for mammographic images still miss some malignant cases on the one hand, and produce too many false-positive (FP) detections with respect to the number of true-positive (TP) detections on the other. An attempt has been described to improve the TP ratio per image and to decrease the number of FP errors in the hierarchical template matching detector of regions of interest (ROIs) for cancerous masses by eliminating the images of linear structures (LSs) from the mammograms. The LSs were detected with an accumulation-based line detector. The measure of correctness of the ROIs detection was discussed and the quality of the detector, represented by free receiver operating characteristics curves, was compared with the human-eye observations. The result is that the widely used measure of detection correctness seems to underestimate the detection quality made by a human. Tests were performed on the mammograms from the MIAS database.     

Photoinduced Double Proton Transfer: Inter- and Intramolecular Cases

Photoinduced two-proton tautomerization has been studied in two types of chromophores: (i) alcohol complexes of azaaromatic molecules possessing both proton donor and acceptor groups; (ii) constitutional isomers of porphyrin. The reaction path for the intermolecular process may involve solvent reorientation around the excited chromophore. In this case, rapid internal conversion is activated, efficiently competing with proton transfer. Another possibility arises if cyclic, doubly-hydrogen-bonded complexes exist already in the ground state. Excitation of such species leads to a fast tautomerization, which is not stopped even at low temperatures. Excited-state double proton transfer also has been observed in cyclic dimers in the crystal phase. In porphyrin isomers, the rate of the process is a function of the strength of the intramolecular hydrogen bond. Dependence of the phototautomerization rate on temperature and on the nature of the surrounding matrix has also been studied.     

Electrochemical and high temperature physicochemical properties of orthorhombic LiMnO2

In this work we report the investigation of the structural and the electrical properties of orthorhombic LiMnO₂ in a wide temperature range in air and in high purity argon (N5). Also we present a correlation between the electrical and the electrochemical properties of the material upon lithium deintercalation. Moreover, its chemical stability against LiPF₆ based liquid electrolyte at elevated temperatures was measured and compared with other cathode materials.