Prediction of the backwater level due to bridge constriction in waterways

This article proposes a mathematical method to calculate the backwater level at bridge constrictions for compound channels. Such a model is necessary, as many of the previously developed simple formulas yield inaccurate results. Parametric studies on a single‐opening semicircular arch, single‐opening semielliptical arch and single‐opening straight deck bridge were also conducted using the commercial software HEC‐RAS to investigate the influences of different factors on backwater level. The results indicated that the Froude number, opening ratio, discharge and roughness coefficient impact the backwater level considerably. Hence, a simple mathematical method was developed based on these parameters and validated using experimental data in a symmetrical two‐stage channel with different roughness coefficients for different types of bridge models. The results obtained using the proposed formula corresponded well with the experimental data and the results obtained using the energy method, which is accurate and the most commonly used method to calculate backwater level.     

Influence of drying conditions and plasticizer-to-binder ratio on the water-based tape casting of La0.6Sr0.4Co0.2Fe0.8O3−δ

Tape casting is a flexible technique for manufacturing scalable ceramic sheets. This study fabricated La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF6428) tapes using water-based tape casting. A high molecular weight plasticizer, polyethylene glycol 4000, was chosen to balance flexibility and mechanical strength. Adjusting the plasticizer-to-binder ratio (R-value) and increasing relative humidity during drying led to crack-free and flawless green tapes of 330 µm. The uniform polymer matrix improved homogeneity and consistency as well. An applicable suspension formulation was developed for the water-based fabrication of LSCF tapes for continuous production.     

Development of chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis

The aim of this research was to develop chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate as a buccal mucoadhesive patch to treat desquamative gingivitis, which was fabricated through an environmental friendly process. Mucoadhesive films increase the advantage of higher efficiency and drug localization in the affected region. In this research, mucoadhesive films, for the release of hydrocortisone sodium succinate, were prepared using different ratios of chitosan, gelatin and keratin. In the first step, chitosan and gelatin proportions were optimized after evaluating the mechanical properties, swelling capacity, water uptake, stability, and biodegradation of the films. Then, keratin was added at different percentages to the optimum composite of chitosan and gelatin together with the drug. The results of surface pH showed that none of the samples were harmful to the buccal cavity. FTIR analysis confirmed the influence of keratin on the structure of the composite. The presence of a higher amount of keratin in the composite films resulted in high mechanical, mucoadhesive properties and stability, low water uptake and biodegradation in phosphate buffer saline (pH?=?7.4) containing 10⁴?U/ml lysozyme. The release profile of the films ascertained that keratin is a rate controller in the release of the hydrocortisone sodium succinate. Finally, chitosan/gelatin/keratin composite containing hydrocortisone sodium succinate can be employed in dental applications.     

Tryptophan Metabolism and Gut-Brain Homeostasis

Tryptophan is an essential amino acid critical for protein synthesis in humans that has emerged as a key player in the microbiota-gut-brain axis. It is the only precursor for the neurotransmitter serotonin, which is vital for the processing of emotional regulation, hunger, sleep, and pain, as well as colonic motility and secretory activity in the gut. Tryptophan catabolites from the kynurenine degradation pathway also modulate neural activity and are active in the systemic inflammatory cascade. Additionally, tryptophan and its metabolites support the development of the central and enteric nervous systems. Accordingly, dysregulation of tryptophan metabolites plays a central role in the pathogenesis of many neurologic and psychiatric disorders. Gut microbes influence tryptophan metabolism directly and indirectly, with corresponding changes in behavior and cognition. The gut microbiome has thus garnered much attention as a therapeutic target for both neurologic and psychiatric disorders where tryptophan and its metabolites play a prominent role. In this review, we will touch upon some of these features and their involvement in health and disease.     

Symmetry-Based Indexing of Image Databases

The use of shape as a cue for indexing into pictorial databases has been traditionally based on global invariant statistics and deformable templates, on the one hand, and local edge correlation on the other. This paper proposes an intermediate approach based on a characterization of the symmetry in edge maps. The use of symmetry matching as a joint correlation measure between pairs of edge elements further constrains the comparison of edge maps. In addition, a natural organization of groups of symmetry into a hierarchy leads to a graph-based representation of relational structure of components of shape that allows for deformations by changing attributes of this relational graph. A graduated assignment graph matching algorithm is used to match symmetry structure in images to stored prototypes or sketches. The results of matching sketches and grey-scale images against a small database consisting of a variety of fish, planes, tools, etc., are promising.     

Parts of visual form: computational aspects

Underlying recognition is an organization of objects and their parts into classes and hierarchies. A representation of parts for recognition requires that they be invariant to rigid transformations, robust in the presence of occlusions, stable with changes in viewing geometry, and be arranged in a hierarchy. These constraints are captured in a general framework using notions of a PART-LINE and a PARTITIONING SCHEME. A proposed general principle of “form from function” motivates a particular partitioning scheme involving two types of parts, neck-based and limb-based. Neck-based parts arise from narrowings in shape, or the local minima in distance between two points on the boundary, while limb-based parts arise from a pair of negative curvature minima which have “co-circular” tangents. In this paper, we present computational support for the limb-based and neck-based parts by showing that they are invariant, robust, stable and yield a hierarchy of parts. Examples illustrate that the resulting decompositions are robust in the presence of occlusion and clutter for a range of man-made and natural objects, and lead to natural and intuitive parts which can be used for recognition     

Segregation of moving objects using elastic matching

We present a method for figure-ground segregation of moving objects from monocular video sequences. The approach is based on tracking extracted contour fragments, in contrast to traditional approaches which rely on feature points, regions, and unorganized edge elements. Specifically, a notion of similarity between pairs of curve fragments appearing in two adjacent frames is developed and used to find the curve correspondence. This similarity metric is elastic in nature and in addition takes into account both a novel notion of transitions in curve fragments across video frames and an epipolar constraint. This yields a performance rate of 85% correct correspondence on a manually labeled set of frame pairs. Color/intensity of the regions on either side of the curve is also used to reduce the ambiguity and improve efficiency of curve correspondence. The retrieved curve correspondence is then used to group curves in each frame into clusters based on the pairwise similarity of how they transform from one frame to the next. Results on video sequences of moving vehicles show that using curve fragments for tracking produces a richer segregation of figure from ground than current region or feature-based methods.     

Euler Spiral for Shape Completion

In this paper we address the curve completion problem, e.g., the geometric continuation of boundaries of objects which are temporarily interrupted by occlusion. Also known as the gap completion or shape completion problem, this problem is a significant element of perceptual grouping of edge elements and has been approached by using cubic splines or biarcs which minimize total curvature squared (elastica), as motivated by a physical analogy. Our approach is motivated by railroad design methods of the early 1900's which connect two rail segments by transition curves, and by the work of Knuth on mathematical typography. We propose that in using an energy minimizing solution completion curves should not penalize curvature as in elastica but curvature variation. The minimization of total curvature variation leads to an Euler Spiral solution, a curve whose curvature varies linearly with arclength. We reduce the construction of this curve from a pair of points and tangents at these points to solving a nonlinear system of equations involving Fresnel Integrals, whose solution relies on optimization from a suitable initial condition constrained to satisfy given boundary conditions. Since the choice of an appropriate initial curve is critical in this optimization, we analytically derive an optimal solution in the class of biarc curves, which is then used as the initial curve. The resulting interpolations yield intuitive interpolation across gaps and occlusions, and are extensible, in contrast to the scale-invariant version of elastica. In addition, Euler Spiral segments can be used in other applications of curve completions, e.g., modeling boundary segments between curvature extrema or modeling skeletal branch geometry.     

Nickel Nanoparticle Catalyzed Growth of Multiwall CNTs on Copper thin Films Substrate

Protection of Metals and Physical Chemistry of Surfaces - Significant applications of metallic nanocatalysts motivated us to study the role of catalyst contents by choosing Cu–Ni nanocatalyst...