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In the Lorentz Heisenberg space H3 endowed with flat metric g3, a translation surface is parametrized by r(x, y) = γ₁(x)*γ₂(y), where γ₁ and γ₂ are two planar curves lying in planes, which are not orthogonal. In this article, we classify translation surfaces in H3, which satisfy some algebraic equations in terms of the coordinate functions and the Laplacian operator with respect to the first fundamental form of the surface.

In this paper, we classify some type of space-like translation surfaces of H3 endowed with flat metric g3 under the conditionΔr_i = λ_ir_i. We will develop the system which describes surfaces of type finite in H3. For solve the system thus obtained, we will use the calculation variational. Finally, we will try to give performances geometric surfaces that meet the condition imposed.

Classification of six types of translation surfaces of finite type in the three-dimensional Lorentz Heisenberg group H3.

The subject of this paper lies at the border of geometry differential and spectral analysis on manifolds. Historically, the first research on the study of sub-finite type varieties began around the 1970 by B.Y.Chen. The idea was to find a better estimate of the mean total curvature of a compact subvariety of a Euclidean space. In fact, the notion of finite type subvariety is a natural extension of the notion of a minimal subvariety or surface, a notion directly linked to the calculation of variations. The goal of this work is the classification of surfaces in H3, in other words the surfaces which satisfy the condition/Delta (ri) = /Lambda (ri), such that the Laplacian is associated with the first, fundamental form.

Fibrous porous media have a wide variety of applications in insulation, filtration, acoustics, sensing, and actuation. To design such materials, computational modeling methods are needed to engineer the properties systematically. There is a lack of efficient approaches to build and modify those complex structures in computers. The paper aims to discuss these issues.

In this paper, the authors generalize a previously developed periodic surface (PS) model so that the detailed shapes of fibers in porous media can be modeled. Because of its periodic and implicit nature, the generalized PS model is able to efficiently construct the three-dimensional representative volume element (RVE) of randomly distributed fibers. A physics-based empirical force field method is also developed to model the fiber bending and deformation.

Integrated with computational fluid dynamics (CFD) analysis tools, the proposed approach enables simulation-based design of fibrous porous media.

In the future, the authors will investigate robust approaches to export meshes of PS models directly to CFD simulation tools and develop geometric modeling methods for composite materials that include both fibers and resin.

The proposed geometric modeling method with implicit surfaces to represent fibers is unique in its capability of modeling bent and deformed fibers in a RVE and supporting design parameter-based modification for global configuration change for the purpose of macroscopic transport property analysis.

The purpose of this study was to develop a new folding method for modeling complicated folded fabric with surfaces of revolution.

Irregular wrinkles and mesh distortions easily appear in the fold modeling of a complex curved surface. Aimed at this key technical problem, the segmentation mapping folding method (SMFM) is proposed in this paper. First, high-precision flattened planes were obtained by using segmentation mapping techniques. Second, the segmented planes were transformed into a folded and continuous geometric model by using matrix transformations. Finally, initial stress was used to modify the geometric folding errors, which ensured agreement with the inflated flexible fabric’s geometry and the original design.

Compared with the traditional folding method, SMFM has the advantages of good finite-element mesh quality, large radial compression rate, regular folds, etc. The surface area error and the volume error of the inflated single torus established by SMFM were only 1.2 per cent, showing that SMFM has high modeling accuracy. The numerical results of an inflatable re-entry vehicle are presented to demonstrate the reliability, feasibility and applicability of SMFM. Moreover, the stress modification reduced the problems of stress concentration and mesh distortions, improving the accuracy and stability of the numerical calculations.

In this paper, for the first time, a folding method for modeling complicated folded fabric is proposed. This methodology can be used to model the multidimensional compression and regular folds of complex surfaces of revolution that cannot be flattened and to improve the accuracy and stability of the numerical calculations.

The purpose of this paper is to use translation theory to develop a framework (called FTRA) that explains how companies adopt agile methods in a discourse of fragmentation and articulation.

A qualitative multiple case study of six firms using the Scrum agile methodology. Data were collected using mixed methods and analyzed using three progressive coding cycles and analytic induction.

In practice, people translate agile methods for local settings by choosing fragments of the method and continuously re-articulating them according to the exact needs of the time and place. The authors coded the fragments as technological rules that share relationships within a framework spanning two dimensions: static-dynamic and actor-artifact.

For consistency, the six cases intentionally represent one instance of agile methodology (Scrum). This limits the confidence that the framework is suitable for other kinds of methodologies.

The FTRA framework and the technological rules are promising for use in practice as a prescriptive or even normative frame for governing methodology adaptation.

Framing agile adaption with translation theory surfaces how the discourse between translocal (global) and local practice yields the social construction of agile methods. This result contrasts the more functionalist engineering perspective and privileges changeability over performance.

The use of translation theory and the FTRA framework to explain how agile adaptation (in particular Scrum) emerges continuously in a process where method fragments are articulated and re-articulated to momentarily suit the local setting. Complete agility that rapidly and elegantly changes its own environment must, as a concomitant, rapidly and elegantly change itself. This understanding also elaborates translation theory by explaining how the articulation and re-articulation of ideas embody the means by which ideas travel in practice.

With the development of 3D printing or additive manufacturing (AM), curved layer fused deposition modeling (CLFDM) has been researched to cope with the flat layer AM inherited problems, such as stair-step error, anisotropy and the time-cost and material-cost problems from the supporting structures. As one type of CLFDM, cylindrical slicing has obtained some research attention. However, it can only deal with rotationally symmetrical parts with a circular slicing layer, limiting its application. This paper aims to propose a ray-based slicing method to increase the inter-layer strength of flat layer-based AM parts to deal with more general revolving parts.

Specifically, the detailed algorithm and implementation steps are given with several examples to enable readers to understand it better. The combination of ray-based slicing and helical path planning has been proposed to consider the nonuniform path spacing between the adjacent paths in the same curved layer. A brief introduction of the printing system is given, mainly including a 3D printer and the graphical user interface.

The preliminary experiments are successfully conducted to verify the feasibility and versatility of the proposed and improved slicing method for the revolving thin-wall parts based on a rotary 3D printer.

This research is early-stage work, and the authors are intended to explore the process and show the initial feasibility of ray-based slicing for revolving thin-wall parts using a rotary 3D printer. In general, this research provides a novel and feasible slicing method for multiaxis rotary 3D printers, making manufacturing revolving thin-wall and complex parts possible.

The purpose of this paper is to examine the concept of translation equivalence in extant research on translation in accounting: What is the equivalence that is expected of translation, and how is it assumed to come into being? This paper presents a coherent, theoretically informed approach to how different views on equivalence are connected to the objective of international comparability in financial accounting and how related, often-underlying assumptions intertwine in this discussion.

This paper takes an interdisciplinary approach by utilizing equivalence theories from the discipline of translation studies. It canvasses two dichotomy-like approaches – natural versus directional equivalence and formal versus dynamic equivalence – to compose a theoretical framework within which to analyze 25 translation-related papers discussing accounting harmonization published from 1989 to 2018.

This paper presents evidence of theoretical contradictions likely to affect the development of translation research in accounting if they go unrecognized. Moreover, the analysis suggests that these contradictions are likely to originate in the assumptions of mainstream accounting research, which neglect both the constructed nature of equivalence and the socially constructed nature of accounting concepts.

Despite the significance of translation for the objective of international comparability, this paper is the first comprehensive theoretical approach to equivalence in accounting research. It responds to a recognized demand for studying equivalence and its limitations, challenges many of the expectations accounting research places on translation and discusses the possible origins of related assumptions.

Shrink fit is an important method used in mechanical transmission, but the design of these connections is not sufficiently precise due to lack of knowledge regarding the effects of many parameters. The paper aims to discuss these issues.

This paper presents the torque capacity and contact stress analysis for a new shrink disc by numerical analysis and experimental methods. Torque capacity analysis aims to predict the effectiveness of mechanical transmission, and to check the structural safety. Stress-strain curves are measured using the universal testing machine, and Bilinear Kinematic Hardening rate-independent plasticity model characterises the elastic-plastic response of the materials.

The numerical result shows that there is no plastic deformation at the interference regions, and the maximum equivalent strain happens on the inner ring. The stress of outer ring is decreased with radius increasing, and shows a periodic variation along the circumference, but stress concentration happens at the threaded holes. Finally, the torque capacity of the shrink disc system is measured through a developed test machine, and the torque capacity difference between numerical and experimental results is about 3.3 per cent.

This paper presents a numerical and experimental carrying capacity analysis for a shrink disc. Plasticity model characterises the materials’ elastic-plastic response based testing. A test machine is designed to measure the torque capacity; the error is about 3.3 per cent.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Technical Reports and Translations of the United States National Aeronautics and Space Administration and publications of other similar Research Bodies as issued.

The purpose of this paper is to critically review the literature related to dimensional accuracy and surface roughness for fused deposition modeling and similar extrusion-based additive manufacturing or rapid prototyping processes.

A systematic review of the literature was carried out by focusing on the relationship between process and product design parameters and the dimensional and surface properties of finished parts. Methods for evaluating these performance parameters are also reviewed.

Fused deposition modeling® and related processes are the most widely used polymer rapid prototyping processes. For many applications, resolution, dimensional accuracy and surface roughness are among the most important properties in final parts. The influence of feedstock properties and system design on dimensional accuracy and resolution is reviewed. Thermal warping and shrinkage are often major sources of dimensional error in finished parts. This phenomenon is explored along with various approaches for evaluating dimensional accuracy. Product design parameters, in particular, slice height, strongly impact surface roughness. A geometric model for surface roughness is also reviewed.

This represents the first review of extrusion AM processes focusing on dimensional accuracy and surface roughness. Understanding and improving relationships between materials, design parameters and the ultimate properties of finished parts will be key to improving extrusion AM processes and expanding their applications.