Design Of Functional Components Research Articles

UCDM: A User-Centric Data Model in Power Blockchain

Background: As innovative information technology, blockchain has combined the advantages of decentralization, immutability, data provenance, and contract operation automatically, which can be used to solve the issues of single point failure, high trading cost, low effectiveness, and data potential risk in power trading. However, in the traditional power blockchain, the design of functional components in blockchain, such as the data structure of the block, does not take the actual features of power into account, thus leading to a performance bottleneck in practical application. Motivated by business characteristics of power trading, a user-centric data model UCDM in consortium blockchain is proposed to achieve efficient data storage and quick data retrieval. Methods: The proposed UCDM is designed by considering the requirements of transaction retrieval and analysis, thus supporting the requirements of concurrent data requests and mass data storage. The ID of each user will independently form its own chain over the blockchain. Results: Compared with the traditional data model, the extensive experimental results demonstrate that the proposed UCDM has shorter processing delay, higher throughput, and shorter response latency, thus having practical value. Conclusion: UCDM is an effective solution to the transaction retrieval and analysis in power blockchain. Furthermore, the participant of the blockchain network has a unique identity over the world, which ensures high security during trading.

Effect of datum system and datum hierarchy on the design of functional components produced by additive manufacturing: a systematic review and analysis

The evolving technology of additive manufacturing (AM) is posing novel challenges in manufacturing practice since nowadays functional, end-use components, and assemblies are produced by commercially available AM equipment. In order to safeguard the functionality and the interchangeability of a part, the designer must clearly denote a set of Geometrical Product Specifications (GPS) in the 3D model or in the engineering drawing by using the existing standards, e.g., ISO 1101, ISO 5459, and ISO 1660. Apparently, the family of ISO GPS standards that are currently used in design, manufacture, and verification has been developed so as to address the needs of traditional manufacturing processes rather than AM. Supported by numerous recent publications, the argument that current standardization does not sufficiently support the geometrical specification and verification of AM parts is getting more and more popular. The paper investigates and questions the need for the development of AM process-specific standards, related to the tolerancing and verification of mechanical components, as encountered with castings, forgings, and composites. Focusing on the most critical issue of datum establishment and datum hierarchy, the capability of existing tolerancing tools, as provided by the ISO GPS standards, to serve the process-specific AM needs is systematically examined. Moreover, major AM process-specific parameters such as build direction, layer thickness, support structure, and hatching plan are linked with the datum system designation and datum hierarchy tasks through a design case study and analysis. The major findings of this research pointing towards the establishment of AM-specific design-for-accuracy good practices are presented and discussed.

Mechanical behavior of polymeric selective laser sintered ligament and sheet based lattices of triply periodic minimal surface architectures

Advances in additive manufacturing triggered a paradigm shift in the design of functional components allowing for complex topology-driven cellular lattices to be incorporated for the aim of reducing weight, enhancing multi-functionality, and facilitating manufacturability. In this paper, the compressive mechanical behavior of different polymeric lattices based on triply periodic minimal surfaces (TPMS) are investigated both experimentally and computationally. The behavior of two classes of TPMS lattices are investigated; sheet- and ligament-based lattices. Samples are fabricated using the laser powder bed fusion technique, selective laser sintering, and characterized using micro-Computed Tomography (micro-CT) and Scanning Electron Microscopy (SEM). A finite-deformation hyperelastic-viscoplastic-damage constitutive model is calibrated and employed to capture the full compressive behavior of lattices. The computational results are compared to and validated against corresponding experimental results. Results show that sheet-based polymeric TPMS lattices exhibit a stretching-dominated mode of deformation and prove to have superior stiffness and strength as compared to TPMS ligament-based lattices. The numerical simulations are in good agreement with experimental results for ligament-based lattices while significant deviation from experimental results is observed for the sheet-based lattices which is attributed to uncertainty in measuring the actual relative density and relatively higher manufacturing defects.

EIMAKP: Heterogeneous Cross-Domain Authenticated Key Agreement Protocols in the EIM System

In recent years, instant messaging (IM) has increasingly become a popular communication technology around the world, and the enterprise instant messaging (EIM) system is one of IM’s applications for enterprise use. The existing studies of EIM systems are directed at the design of functional components and the process of communication, which are usually based on XMPP protocol suite. However, in this paper, the security of EIM is more concerned from another perspective, which is the problem of identity authentication and key agreement between users and services. Several EIM systems are based on public key infrastructure (PKI) to achieve the high-security requirements of enterprises, while identity-based cryptography (IBC) brings new development direction for EIM systems. Although most of the EIM applications are applied independently in different enterprises, users’ heterogeneous cross-domain service access has become an inevitable trend. However, there is still no heterogeneous cross-domain authentication protocol between the PKI domain and the IBC domain having been proposed. Therefore, in order to address this problem, a novel and detailed heterogeneous cross-domain authenticated key agreement scheme is proposed in this paper. By utilizing the PKI-based distributed trust model and the access authorization tickets, this scheme can realize interconnection and seamless authentication between the PKI domain and the IBC domain. Analysis shows that the proposed scheme is theoretically correct, while guaranteeing high security and efficiency.

Influence of Structural Defects on the Electronic Properties of Carbon Nanotubes Examined by Scanning Tunnelling Microscopy

AbstractThe electronic properties of carbon nanotubes are quite often drastically affected by the presence of defects that can develop during nanotube growth, processing or characterization too. Some of these defects such as pentagon-heptagon rings, substitutional impurities, vacancies and dislocations are of topological nature, and can sometimes create on-tube intramolecular junctions, as found by previous scanning tunnelling microscopy studies.Our recent STM experiments reveal for the first time a much more complicated junction structure, a hybrid single-walled carbon nanotube consisting of a distinct coiled structure located between two straight segments, each of different helicity. We characterise the hybrid junction at the atomic level and describe its electronic behaviour that has important implications in the practical design of functional components for nanoelectronic applications.