Influence of input energy on mechanical properties of laser powder bed fused AISI 304L stainless steel

“Powder Bed Fusion process with selective laser melting technique is popularly adopted in additive manufacturing area on account of its layer by layer manufacturing fashion capable of fabricating components with complex internal and external geometries and structures. However, the process-property map is unique and vital for different materials and AM configurations used for fabrication. The process parameter is identified as a significant factor that heavily influences the properties and performances of the printed materials. Current work aimed to extend the existing knowledge on Laser Powder Bed Fusion fabricated AISI 304L by accessing the influence of varying energy input on the mechanical performance. 304L specimens with densities ranging from ~97% to ~99% were produced by varying scan speed and hatch spacing. The result indicated no distinguishing difference was observed of density, hardness, ultimate tensile strength, and uniform elongation once energy density reached more than 47.6 J/mm3. Below this ED, lack of fusion and insufficient overlaps between adjacent scan tracks gave rise to the poor bonding in and between layers, which induced the poor mechanical performance of the printed metal. However, at the highest energy density, impact toughness was also deteriorated by the keyhole porosity induced by the excess remelting and accumulated along the partition line. Anisotropy in tensile and impact performance was clearly observed. By means of varying input energy put the anisotropy in impact performance was modified”--Abstract, page iv

Three dimensional norm-based knowledge management for knowledge intensive business service organizations: an organizational semiotics perspective

The utilization of knowledge enables knowledge intensive business service (KIBS) organizations, such as law firms, to perform and deliver value to their customers. Organizational semiotics views norms as knowledge that are developed through practical experience of human agents in organizations. Building on organizational semiotics and knowledge management, this paper proposes a three dimensional norm-based knowledge management (3DNKM) framework for legal sector in the UK. Abductive reasoning is adopted for guiding the research process in this paper. The three identified contextual dimensions of knowledge include customer, practice area and lawyer. For each dimension, there are informal, formal and technical norms establishing context-based knowledge. The proposed framework provides a way for KIBS organizations to manage the intertwined norms from the three dimensions and various levels

Work Function of Single-wall Silicon Carbide Nanotube

Using first-principles calculations, we study the work function of single wall silicon carbide nanotube (SiCNT). The work function is found to be highly dependent on the tube chirality and diameter. It increases with decreasing the tube diameter. The work function of zigzag SiCNT is always larger than that of armchair SiCNT. We reveal that the difference between the work function of zigzag and armchair SiCNT comes from their different intrinsic electronic structures, for which the singly degenerate energy band above the Fermi level of zigzag SiCNT is specifically responsible. Our finding offers potential usages of SiCNT in field-emission devices.Comment: 3 pages, 3 figure