Compensation for Uneven Surfaces When Building Laser Deposited Structures

Direct Laser Deposition (DLD) is a blown-powder laser deposition process that can be used to quickly produce, modify or repair fully-dense metallic parts by a layered manufacturing method. However, uneven substrate surfaces often cause variation in the deposited layer which is magnified by succeeding layers. Research carried out at the University of Liverpool has resulted in a non-feedback layer height controlling process based on controlling the shape of the powder streams emitted from a four-port side feed nozzle. This method limits deposited layer height by causing a sharp reduction of catchment efficiency in the vertical plane at a fixed distance from the powder feed nozzle, and is therefore capable of depositing a consistent layer height in spite of power, powder flow or process velocity variation. This paper demonstrates how this method of layer height control can compensate for irregular substrate surfaces in the production of accurate DLD parts.Mechanical Engineerin

Best Practices of Honor Societies

Academic honor societies are widely available within university communities. These student organizations can fill valuable roles within engineering departments. The inception of engineering-related honor societies followed the establishment of engineering education within American universities. Honor societies with their student focus grew as complementary organizations to the professional societies for engineering disciplines. The national or international structure of honor societies generally provides considerable resources for professional education, leadership training, and service activity. For departments, an honor society chapter can provide engagement with students, alumni, community, etc. However, the existence of an honor society chapter at an institution does not necessarily mean that the chapter is effectively serving the host department(s) and its engineering students. This paper describes commonalities among engineering honor societies, the possible roles of an honor society within an engineering department, and some best practices for effective honor society chapters. Specific examples from the operation of IEEE-Eta Kappa Nu (IEEE-HKN), the honor society of the Institute of Electrical and Electronics Engineers (IEEE), are given.Cockrell School of Engineerin

Juvenile convicts and their colonial familial lives

Convicts were transported from Britain to Van Diemen’s Land from 1803 until 1853. Approximately 10 000 - 13 000 juveniles were among the 148 000 convicts transported. This article has traced the lives of female and male juvenile convicts transported, who were sentenced at the Old Bailey (the Central Criminal Court in London), and voyaged to Van Diemen’s Land. By exploring individual lives, and contextualising their experiences, it is possible to go beyond the circumstances of offending – through to their punishment period, to their lives upon release. This article will focus on one aspect of juvenile convict lives post-transportation – their familial life. The method of nominal record-linkage has been used across a variety of criminal and non-criminal records (including civil records and newspapers) in order to build up a picture of these young offenders. Going beyond the institution and focusing directly on female and male juveniles is important in understanding the lives of this unique group. From the behaviour of the juvenile convicts themselves, to the decisions of the administrators and the conditions of the penal colony into which they were thrust; Were these female and male juvenile convicts able to form ‘settled’ colonial lives and which factors inhibited or facilitated this process

Version Control in Online Software Repositories

Software version control repositories provide a uniform and stable interface to manage documents and their version histories. Unfortunately, Open Source systems, for example, CVS, Subversion, and GNU Arch are not well suited to highly collaborative environments and fail to track semantic changes in repositories. We introduce document provenance as our Description Logic framework to track the semantic changes in software repositories and draw interesting results about their historic behaviour using a rule-based inference engine. To support the use of this framework, we have developed our own online collaborative tool, leveraging the fluency of the modern WikiWikiWeb

Analog voicing detector responds to pitch

Modified electronic voice encoder /Vocoder/ includes an independent analog mode of operation in addition to the conventional digital mode. The Vocoder is a bandwidth compression equipment that permits voice transmission over channels, having only a fraction of the bandwidth required for conventional telephone-quality speech transmission

Version Control in Online Software Repositories

Software version control repositories provide a uniform and stable interface to manage documents and their version histories. Unfortunately, Open Source systems, for example, CVS, Subversion, and GNU Arch are not well suited to highly collaborative environments and fail to track semantic changes in repositories. We introduce document provenance as our Description Logic framework to track the semantic changes in software repositories and draw interesting results about their historic behaviour using a rule-based inference engine. To support the use of this framework, we have developed our own online collaborative tool, leveraging the fluency of the modern WikiWikiWeb

The Alternating Surface Segmented Lap Joint: a Design for Thin Highly Loaded Joints

The combination of thin airfoil sections and high aerodynamic loads on many wind tunnel models presents a major problem for attachment of flap elements. Conventional methods of attaching fixed control elements such as lap and tongue-in-groove joints are not rigid enough to provide surface continuity required in high Reynolds number research. For the extreme cases, the solution has been to fabricate separate wings for each flap setting with the flap element being and integral part of the wing. Here an attractive solution to this problem, the alternating surface segmented lap joint, is discussed. This joint provides increased rigidity and lower stress levels than conventional joints. Additionally, attachment fastener loading is low and the joint can be designed to accommodate high shear levels due to bending without the use of dowel pins

Investigation of Low-temperature Solders for Cryogenic Wind Tunnel Models

The advent of high Reynolds number cryogenic wind tunnels has forced alteration of manufacturing and assembly techniques and eliminated usage of many materials associated with conventional wind tunnel models. One of the techniques affected is soldering. Solder alloys commonly used for wind tunnel models are susceptible to low-temperature embrittlement and phase transformation. The low-temperature performance of several solder alloys is being examined during research and development activities being conducted in support of design and fabrication of cryogenic wind tunnel models. Among the properties examined during these tests are shear strength, surface quality, joint stability, and durability when subjected to dynamic loading. Results of these tests and experiences with recent models are summarized