Constructing G2 Continuous Curve on Freeform Surface with Normal Projection

AbstractThis article presents a new method for G2 continuous interpolation of an arbitrary sequence of points on an implicit or parametric surface with prescribed tangent direction and curvature vector, respectively, at every point. First, a G2 continuous curve is constructed in three-dimensional space. Then the curve is projected normally onto the given surface. The desired interpolation curve is just the projection curve, which can be obtained by numerically solving the initial- value problems for a system of first-order ordinary differential equations in the parametric domain for parametric case or in three-dimensional space for implicit case. Several shape parameters are introduced into the resulting curve, which can be used in subsequent interactive modification so that the shape of the resulting curve meets our demand. The presented method is independent of the geometry and parameterization of the base surface. Numerical experiments demonstrate that it is effective and potentially useful in numerical control (NC) machining, path planning for robotic fibre placement, patterns design on surface and other industrial and research fields

Constructing G2 Continuous Curve on Freeform Surface with Normal Projection

AbstractThis article presents a new method for G2 continuous interpolation of an arbitrary sequence of points on an implicit or parametric surface with prescribed tangent direction and curvature vector, respectively, at every point. First, a G2 continuous curve is constructed in three-dimensional space. Then the curve is projected normally onto the given surface. The desired interpolation curve is just the projection curve, which can be obtained by numerically solving the initial- value problems for a system of first-order ordinary differential equations in the parametric domain for parametric case or in three-dimensional space for implicit case. Several shape parameters are introduced into the resulting curve, which can be used in subsequent interactive modification so that the shape of the resulting curve meets our demand. The presented method is independent of the geometry and parameterization of the base surface. Numerical experiments demonstrate that it is effective and potentially useful in numerical control (NC) machining, path planning for robotic fibre placement, patterns design on surface and other industrial and research fields

HRBF-Fusion:Accurate 3D Reconstruction from RGB-D Data Using On-the-fly Implicits

Reconstruction of high-fidelity 3D objects or scenes is a fundamental research problem. Recent advances in RGB-D fusion have demonstrated the potential of producing 3D models from consumer-level RGB-D cameras. However, due to the discrete nature and limited resolution of their surface representations (e.g., point- or voxel-based), existing approaches suffer from the accumulation of errors in camera tracking and distortion in the reconstruction, which leads to an unsatisfactory 3D reconstruction. In this paper, we present a method using on-the-fly implicits of Hermite Radial Basis Functions (HRBFs) as a continuous surface representation for camera tracking in an existing RGB-D fusion framework. Furthermore, curvature estimation and confidence evaluation are coherently derived from the inherent surface properties of the on-the-fly HRBF implicits, which devote to a data fusion with better quality. We argue that our continuous but on-the-fly surface representation can effectively mitigate the impact of noise with its robustness and constrain the reconstruction with inherent surface smoothness when being compared with discrete representations. Experimental results on various real-world and synthetic datasets demonstrate that our HRBF-fusion outperforms the state-of-the-art approaches in terms of tracking robustness and reconstruction accuracy

Adhesion and cohesion of epoxy-based industrial composite coatings

Epoxy is widely adopted in the coating industry because of its excellent performance, which can be applied to the surfaces of metal and non-metal structures for protection and/or decoration purposes. The strength of adhesion and cohesion is an essential prerequisite for coating, which will directly affect the performance and its applications. In the light of the mechanisms of adhesion and cohesion, state-of-the-art of technical enhancements on epoxy-based coating systems, performed over the past few years, are summarized and analyzed in this work. Considering the difference of failure modes, comparisons between the technical methods in terms of the effect in improvement, supporting mechanism, occasions of use, etc. Were compiled. It should be pointed out that research referring to the methods for improving the adhesive and cohesive strength of the applied coating mainly focused on the substrates, fillers and resins, whereas the work related to micro-scale mechanism of adhesion and cohesion, hybridizing nanoscale fillers, and compounded methods have already become a popular path for related research till the moment.</p

Green inhibitors for steel corrosion in acidic environment : state of art

Driven by the increasingly overwhelming environmental issues caused by the widespread application of traditional toxic corrosion inhibitors, eco-friendly inhibitors have attracted strong attention over the past decades. Green inhibitors are produced from cheap and renewable sources and simultaneously offer high inhibition efficiency and low or even zero environmental impact. Herewith, we review recent advances in the field and introduce state-of-the-art methods to validate the inhibitory effects on steel corrosion. Advanced techniques such as weight loss, electrochemical impedance, and potentiodynamic polarization techniques provide ample evidence that green inhibitors are very effective in retarding steel corrosion. We critically examine the mechanisms of corrosion inhibition and relate to the available experimental data. The abundance of π-electrons of multiple bonds and heteroatoms in the form of polar functional groups leads to the active adsorption of the inhibitor's molecules on the steel surface. This article further discusses the adsorption and inhibition mechanisms and the efficiencies of various groups (organic and inorganic) of green corrosion inhibitors for steels in aggressive acid environments, in particular, hydrochloric (HCl) and sulfuric (H2SO4) acids. The future prospects in this multidisciplinary field are formulated and associated with the global challenges of clean energy and manufacturing.</p

Techniques to enhance magnetic permeability in microwave absorbing materials

Microwave Absorbing Materials (MAMs) are gaining popularity in multiple applications in aviation, preventing electromagnetic interference (EMI), ensuring the safety of electromagnetic information and mitigating human health hazards arising due to electromagnetic radiations. Magnetic permeability is one of the fundamental properties that influences Microwave Absorption. This paper reviews the past studies to conclude that the magnetic permeability can be increased by modifying the intrinsic material parameters and by exceeding the Snoek's limit. The important intrinsic parameters and possible methods to modify these parameters and to exceed the Snoek's limit are discussed. The pertinent results in terms of modification effects on the magnetic permeability and Microwave Absorption are also detailed.</p