An Experimental Investigation into Additive Manufacturing-Induced Residual Stresses in 316L Stainless Steel

Additive manufacturing (AM) technology provides unique opportunities for producing net-shape geometries at the macroscale through microscale processing. This level of control presents inherent trade-offs necessitating the establishment of quality controls aimed at minimizing undesirable properties, such as porosity and residual stresses. Here, we perform a parametric study into the effects of laser scanning pattern, power, speed, and build direction in powder bed fusion AM on residual stress. In an effort to better understand the factors influencing macroscale residual stresses, a destructive surface residual stress measurement technique (digital image correlation in conjunction with build plate removal and sectioning) has been coupled with a nondestructive volumetric evaluation method (i.e., neutron diffraction). Good agreement between the two measurement techniques is observed. Furthermore, a reduction in residual stress is obtained by decreasing scan island size, increasing island to wall rotation to 45 deg, and increasing applied energy per unit length (laser power/speed). Neutron diffraction measurements reveal that, while in-plane residual stresses are affected by scan island rotation, axial residual stresses are unchanged. We attribute this in-plane behavior to misalignment between the greatest thermal stresses (scan direction) and largest part dimension.     

An Inquiry-led Personalised Navigation System (IPNS) using multi-dimensional linkbases

The simplicity of the hypertext model behind the World Wide Web is a factor in its success, but this simplicity brings limitations. One of these limitations is embedding links in documents. Open Hypermedia addresses this by instead storing them in separate link databases. Meanwhile, the Adaptive Hypermedia approach seeks to enhance a user's experience by inserting personalised additional content and links on the web page. However, these techniques do not offer the user any control over the adaptation. In this paper, we propose the concept of a multi-dimensional linkbase for adaptive links presentation. Links are created and stored in a single, multi-dimensional, linkbase that provides presentation links based on the user's preferences and profile. We present a web-based system Inquiry-led Personalised Navigation System that implements this multi-dimensional concept for controlling its personalisation of hyperlinks. We give the results of our evaluation, which confirm that user-controlled adaptation is a satisfactory approach to providing users with control over personalisation, and can alleviate the link overload problem.     

‘Piazzadilly!’: the re‐imagining of Piccadilly Circus (1957–72)

Between 1957 and 1972, Piccadilly Circus was the object of a series of major plans and comprehensive redevelopment proposals that would have fundamentally transformed the character of this key central London site. The Piccadilly plans have conventionally been seen as part of an assault by modernist planners and property speculators on the established cityscape. Drawing upon recent perspectives that treat plans as both fantasies of metropolitan life and as complex events, this article argues that the unbuilt plans for Piccadilly were more complicated and contested responses to contemporary attitudes towards the city. The article also argues that these visions altered significantly between the late 1950s and the end of the 1960s, particularly in their responses to flows and movement in the city, and their accommodations of the new consumer cultures of the period.     

An Illuminating Look at Fiber-Optic Transmission Systems

Fiber-optic technology can be applied to many corporate networks and is well suited for many specialized applications involving high-speed data transmission between terminals and a computer or between computers located in the same building. This article describes the components of fiberoptic transmission systems and examines the advantages and disadvantages of these systems.     

Particle/cell separation on microfluidic platforms based on centrifugation effect: a review

Particle/cell separation in heterogeneous mixtures including biological samples is a standard sample preparation step for various biomedical assays. A wide range of microfluidic-based methods have been proposed for particle/cell sorting and isolation. Two promising microfluidic platforms for this task are microfluidic chips and centrifugal microfluidic disks. In this review, we focus on particle/cell isolation methods that are based on liquid centrifugation phenomena. Under this category, we reviewed particle/cell sorting methods which have been performed on centrifugal microfluidic platforms, and inertial microfluidic platforms that contain spiral channels and multi-orifice channels. All of these platforms implement a form of centrifuge-based particle/cell separation: either physical platform centrifugation in the case of centrifugal microfluidic platforms or liquid centrifugation due to Dean drag force in the case of inertial microfluidics. Centrifugal microfluidic platforms are suitable for cases where the preparation step of a raw sample is required to be integrated on the same platform. However, the limited available space on the platform is the main disadvantage, especially when high sample volume is required. On the other hand, inertial microfluidics (spiral and multi-orifice) showed various advantages such as simple design and fabrication, the ability to process large sample volume, high throughput, high recovery rate, and the ability for multiplexing for improved performance. However, the utilization of syringe pump can reduce the portability options of the platform. In conclusion, the requirement of each application should be carefully considered prior to platform selection.     

Detection and characterization of an unknown rice event in Basmati rice products

At the end of 2011, genetic modifications in Basmati rice were discovered for the first time in products placed on the European Union market. The products originated from Pakistan or India. In the EU, no event of genetically modified rice is approved as food or feed. The samples were initially identified by positive PCR screening results. Some of the detected genetically modified DNA sequences were previously identified in insect-resistant rice varieties originating from Asia. In addition to a sequence coding for a cry1Ab/Ac gene driven by the maize ubiquitin promoter, the integration of a 35S CaMV promoter-driven cry2A gene was detected. This is the first notification of the presence of a cry2A gene in Asian rice products in the EU.     

Analysis of the resilience of team performance during a nuclear emergency response exercise

The current work presents results from a cognitive task analysis (CTA) of a nuclear disaster simulation. Audio-visual records were collected from an emergency room team composed of individuals from 26 different agencies as they responded to multiple scenarios in a simulated nuclear disaster. This simulation was part of a national emergency response training activity for a nuclear power plant located in a developing country. The objectives of this paper are to describe sources of resilience and brittleness in these activities, identify cues of potential improvements for future emergency simulations, and leveraging the resilience of the emergency response system in case of a real disaster. Multiple CTA techniques were used to gain a better understanding of the cognitive dimensions of the activity and to identify team coordination and crisis management patterns that emerged from the simulation exercises.