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ORTHOGONAL projections are commonly used for representing three dimensional figures on a sheet of paper, and their object is usually that of conveying shape and dimensions to craftsmen, in order to permit manufacture of mechanical parts.

SECTION (B). GEOMETRIC ASPECTS OF TRIMMED FLIGHT The Relation Between the Various Planes of Reference The preceding analytical investigation of the trimmed conditions has been based upon the use of the particular set of axes advocated in Part I. There we took as the dominant axis the axis of the rotor shaft, and regarded as the dominant plane, plane RS, the plane perpendicular to the rotor shaft. We recall that the choice of this plane as a plane of reference was dictated by the importance attached at the outset to the study of the dynamics of the blade motion. We also pointed out that, from the mechani‐cal point of view, plane SP, the plane of the swash‐plate for in the absence of a swash‐plate, the equivalent ‘plane of no‐feathering’), could alterna‐tively be regarded as the dominant reference plane. But now we sec that if we concentrate on the aerodynamic aspect, the prevalence of the ex‐pressions (?i—?0+?0?1) and (?1—?) ascribe prime importance to the axis of the flapping cone. Now just as in the case of the rotor shaft, we chose to specify its direction by a plane perpendicular to it, so here we shall specify the axis of the flapping cone by any plane perpendicular to it. One such plane is the tip‐path plane: another is the plane through the rotor hub parallel to the tip‐path plane. We shall refer to cither plane as the plane TP, and so long as we are only concerned with directions, no ambiguity will be caused. We now have three planes competing for attention, planes RS, SP and TP, and it is our object to link these planes together and see what roles they play in the description of the motion of the helicopter as a whole, having special regard in all this to the particular position of the helicopter's C.G. It may be added that the relationship between these planes is a prominent feature of certain papers [Refs. (2), (10)], and the phrase ‘the equivalence of flapping and feathering’ is there used to describe the resultant findings. It will be shown that there are two different interpretations of this phrase, and that in one sense, what is implied is no more than the equivalence of alternative geometric descriptions of one and the same motion of a helicopter rotor. On the other hand, the phrase may be taken to mean that a rotor having no flapping hinge at all [such as the one analysed by Squire in Ref. (3)] performs effectively in the same way as one free to flap. Indeed, the results of Ref. (3) are frequently used as the basis of many trim and stability calculations of helicopters with freely flapping rotors, despite the lack of a flapping hinge in the calculations of Ref. (3). We shall see that, in general, this procedure is questionable.

As one of the tomographic imaging techniques, electrical capacitance tomography (ECT) is widely used in many industrial applications. While most ECT sensors have electrodes placed around a cylindrical chamber, the planar ECT sensor has been investigated for depth and defect detection. However, the planar ECT sensor has limited height and depth sensing capability due to its single-sided assessment with the use of only a single-plane design. The purpose of this paper is to investigate a dual-plane miniature planar 3D ECT sensor design using the 3 × 3 matrix electrode array.

The sensitivity map of dual-plane miniature planar 3D ECT sensor was analysed using 3D visualisation, the singular value decomposition and the axial resolution analysis. Then, the sensor was fabricated for performance analysis based on 3D imaging experiments.

The sensitivity map analysis showed that the dual-plane miniature planar 3D ECT sensor has enhanced the height sensing capability, and it is less ill-posed in 3D image reconstruction. The dual-plane miniature planar 3D ECT sensor showed a 28% improvement in reconstructed 3D image quality as compared to the single-plane sensor set-up.

The 3 × 3 matrix electrode array has been proposed to use only the necessary electrode pair combinations for image reconstruction. Besides, the increase in number of electrodes from the dual-plane sensor setup improved the height reconstruction of the test sample.

As laser scanning technology becomes readily available and affordable, there is an increasing demand of using point cloud data collected from a laser scanner to create as-built building information modeling (BIM) models for quality assessment, schedule control and energy performance within construction projects. To enhance the as-built modeling efficiency, this study explores an integrated system, called Auto-Scan-To-BIM (ASTB), with an aim to automatically generate a complete Industry Foundation Classes (IFC) model consisted of the 3D building elements for the given building based on its point cloud without requiring additional modeling tools.

ASTB has been developed with three function modules. Taking the scanned point data as input, Module 1 is built on the basis of the widely used region segmentation methodology and expanded with enhanced plane boundary line detection methods and corner recalibration algorithms. Then, Module 2 is developed with a domain knowledge-based heuristic method to analyze the features of the recognized planes, to associate them with corresponding building elements and to create BIM models. Based on the spatial relationships between these building elements, Module 3 generates a complete IFC model for the entire project compatible with any BIM software.

A case study validated the ASTB with an application with five common types of building elements (e.g. wall, floor, ceiling, window and door).

First, an integrated system, ASTB, is developed to generate a BIM model from scanned point cloud data without using additional modeling tools. Second, an enhanced plane boundary line detection method and a corner recalibration algorithm are developed in ASTB with high accuracy in obtaining the true surface planes. At last, the research contributes to develop a module, which can automatically convert the identified building elements into an IFC format based on the geometry and spatial relationships of each plan.

In order to improve the robustness to noise in point cloud plane fitting, a combined model of improved Cook’s distance (ICOOK) and WTLS is proposed by setting a modified Cook’s increment, which could help adaptively remove the noise points that exceeds the threshold.

This paper proposes a robust point cloud plane fitting method based on ICOOK and WTLS to improve the robustness to noise in point cloud fitting. The ICOOK to denoise the initial point cloud was set and verified with experiments. In the meanwhile, weighted total least squares method (WTLS) was adopted to perform plane fitting on the denoised point cloud set to obtain the plane equation.

(a) A threshold-adaptive Cook’s distance method is designed, which can automatically match a suitable threshold. (b) The ICOOK is fused with the WTLS method, and the simulation experiments and the actual fitting of the surface of the DD motor are carried out to verify the actual application. (c) The results shows that the plane fitting accuracy and unit weight variance of the algorithm in this paper are substantially enhanced.

The existing point cloud plane fitting methods are not robust to noise, so a robust point cloud plane fitting method based on a combined model of ICOOK and WTLS is proposed. The existing point cloud plane fitting methods are not robust to noise, so a robust point cloud plane fitting method based on a combined model of ICOOK and WTLS is proposed.

This study aims to present a numerical study of atomic structure for aluminium nitride (AlN) when the crystal was assumed grown on different orientation of sapphire substrate. The change of the AlN atomic structure with sapphire orientation was associated to the interface between the AlN and the sapphire. The results from this study would provide a guideline in selecting suitable orientation of sapphire for obtaining desirable AlN crystals, in particular, for reducing threading dislocation density in the AlN/sapphire templates for developing UV LEDs.

The approach of atomic structure by visualization for electronic and structural analysis numerical method to develop shape of atomic geometry to evaluate which plane are more suitable for the AlGaN technology UV-LED based.

The calculation based on ratio on first and second layers can be done by introduction of lattice constant.

With plane’s color of cutting plane on bulky materials, all the shape looks the same.

By implementing this method, the authors can save time to find the most suitable plane on the growth structure.

All authors of this research paper have directly participated in the planning, execution or analysis of the study; all authors of this paper have read and approved the final version submitted; the contents of this manuscript have not been copyrighted or published previously; the contents of this manuscript are not now under consideration for publication elsewhere; the contents of this manuscript will not be copyrighted, submitted or published elsewhere, whereas acceptance by the journal is under consideration.

Engineering components/structures are usually subjected to complex and variable loads, which result in random multiaxial stress/strain states. However, fatigue analysis methods under constant loads cannot be directly applied to fatigue life prediction analysis under random loads. Therefore, the purpose of this study is how to effectively evaluate fatigue life under multiaxial random loading.

First, the average phase difference is characterized as the ratio of the number of shear strain cycles to the number of normal strain cycles, and the new non-proportional additional hardening factor is proposed. Then, the determined random typical load spectrum is processed into a simple variable amplitude load spectrum, and the damage in each plane is calculated according to the multiaxial fatigue life prediction model and Miner theory. Meanwhile, the cumulative damage can be calculated separately by projection method. Finally, the maximum projected cumulative damage plane is defined as the critical plane of multiaxial random fatigue.

The fatigue life prediction capability of the method is verified based on test data of TC4 titanium alloy under random multiaxial loading. Most of the predicting results are within double scatter bands.

The objective of this study is to provide a reference for the determination of critical plane and non-proportional additional hardening factor under multiaxial random loading, and to promote the development of multiaxial fatigue from experimental studies to practical engineering applications.

This paper aims to numerically investigate the impact of gas diffusion layer (GDL) anisotropic transport properties on the overall and local performance of polymer electrolyte fuel cells (PEFCs).

A three-dimensional numerical model of a polymer electrolyte fuel cell with a single straight channel has been developed to investigate the sensitivity of the fuel cell performance to the GDL anisotropic transport properties – gas permeability, diffusivity, thermal conductivity and electrical conductivity. Realistic experimentally estimated GDL transport properties were incorporated into the developed PEFC model, and a parametric study was performed to show the effect of these properties on fuel cell performance and the distribution of the key variables of current density and oxygen concentration within the cathode GDL.

The results showed that the anisotropy of the GDL must be captured to avoid overestimation/underestimation of the performance of the modelled fuel cell. The results also showed that the fuel cell performance and the distributions of current density and oxygen mass fraction within the cathode GDL are highly sensitive to the through-plane electrical conductivity of the GDL and, to a lesser extent, the through-plane diffusivity, and the thermal conductivity of the GDL. The fuel cell performance is almost insensitive to the gas permeability of the GDL.

This study improves the understanding of the importance of the GDL anisotropy in the modelling of fuel cells and provides useful insights on improving the efficiency of the fuel cells.

Realistic experimentally estimated GDL transport properties have been incorporated into the PEFC model for the first time, allowing for more accurate prediction of the PEFC performance.

This article seeks to introduce the concept of the Grid‐GMPLS control plane architecture with focus on new services, models, and interoperability issues of Grid‐GMPLS (G²MPLS) and GMPLS control planes. The purpose of this activity is to design, implement and test extensions of the GMPLS Control Plane that can enable the paradigm of a G²MPLS network.

The approach deploys extended GMPLS implementations aiming to facilitate bandwidth provisioning to Grid users.

G²MPLS is a Network Control Plane architecture that implements the concept of Grid Network Services. GNS is a service that allows the provisioning of network and Grid resources in a single‐step through a set of integrated procedures. By providing a unified network/Grid infrastructure the control plane can adapt to the demands of applications having intensive requirements on both computational and network resources.

The project delivers the prototype implementation of G²MPLS. Consideration should be given to involving the vendors of the optical equipment in the development process to incorporate the project findings into their operating systems.

The G²MPLS protocol stack has been designed to be compatible with the ASON/GMPLS architecture. This could lead to possible integration of Grids in the existing operational networks, by overcoming the current limitations of Grids running over dedicated networks with their own administrative procedures.

The paper provides the description of Grid Network Infrastructures with a common and transversal Control Plane approach based on G²MPLS, in which Grid resources and optical network resources are both controlled by the same Control Plane, seamlessly spanning the different Control and Management domains of the network.

Adaptive slicing is a key step in three-dimensional (3D) printing as it is closely related to the building time and the surface quality. This study aims to develop a novel adaptive slicing method based on ameliorative area ratio and accurate cusp height for 3D printing using stereolithography (STL) models.

The proposed method consists of two stages. In the first stage, the STL model is sliced with constant layer thickness, where an improved algorithm for generating active triangular patches, the list is developed to preprocess the model faster. In the second stage, the model is first divided into several blocks according to the number of contours, then an axis-aligned bounding box-based contour matching algorithm and a polygons intersection algorithm are given to compare the geometric information between several successive layers, which will determine whether these layers can be merged to one.

Several benchmarks are applied to verify this new method. Developed method has also been compared with the uniform slicing method and two existing adaptive slicing methods to demonstrate its effectiveness in slicing.

Compared with other methods, the method leads to fewer layers whilst keeping the geometric error within a given threshold. It demonstrates that the proposed slicing method can reach a trade-off between the building time and the surface quality.