Effect of material, geometry, surface treatment and environment on the shear strength of single lap joints

The single lap joint is the most studied type of adhesive joint in the literature. However, the joint strength prediction of such joints is still a controversial issue as it involves a lot of factors that are difficult to quantify such as the overlap length, the yielding of the adherend, the plasticity of the adhesive and the bondline thickness. The most complicated case is that where the adhesive is brittle and the overlap long. In any case, there is still a problem that is even more difficult to take into account which is the durability. There is a lack of experimental data and design criteria when the joint is subjected to high, low or variable temperature and/or humidity. The objective of this work is to carry out and quantify the various variables affecting the strength of single lap joints in long term, especially the effect of the surface preparation. The Taguchi method is used to decrease the number of experimental tests. The effect of material, geometry, surface treatment and environment is studied and it is shown that the main effect is that of the overlap length. In order to quantify the influence of the adhesive (toughness and thickness), the adherend (yield strength and thickness), the overlap, the test speed, the surface preparation and durability on the lap shear strength, the experimental design technique of Taguchi was used in the present study. An experimental matrix of eighteen tests was designed and each test was repeated three times. The influence of the eight previously-mentioned variables could be assessed using the statistical software Statview®. In this paper a simple predictive equation is proposed for the design of single lap joints

The UK risk assessment scheme for all non-native species

1. A pest risk assessment scheme, adapted from the EPPO (European and Mediterranean Plant Protection Organisation) scheme, was developed to assess the risks posed to UK species, habitats and ecosystems by non-native taxa. 2. The scheme provides a structured framework for evaluating the potential for non-native organisms, whether intentional or unintentional introductions, to enter, establish, spread and cause significant impacts in all or part of the UK. Specialist modules permit the relative importance of entry pathways, the vulnerability of receptors and the consequences of policies to be assessed and appropriate risk management options to be selected. Spreadsheets for summarising the level of risk and uncertainty, invasive attributes and economic impact were created. In addition, new methods for quantifying economic impact and summarising risk and uncertainty were explored. 3. Although designed for the UK, the scheme can readily be applied elsewhere

ALICE: The Ultraviolet Imaging Spectrograph aboard the New Horizons Pluto-Kuiper Belt Mission

The New Horizons ALICE instrument is a lightweight (4.4 kg), low-power (4.4 Watt) imaging spectrograph aboard the New Horizons mission to Pluto/Charon and the Kuiper Belt. Its primary job is to determine the relative abundances of various species in Pluto's atmosphere. ALICE will also be used to search for an atmosphere around Pluto's moon, Charon, as well as the Kuiper Belt Objects (KBOs) that New Horizons hopes to fly by after Pluto-Charon, and it will make UV surface reflectivity measurements of all of these bodies as well. The instrument incorporates an off-axis telescope feeding a Rowland-circle spectrograph with a 520-1870 angstroms spectral passband, a spectral point spread function of 3-6 angstroms FWHM, and an instantaneous spatial field-of-view that is 6 degrees long. Different input apertures that feed the telescope allow for both airglow and solar occultation observations during the mission. The focal plane detector is an imaging microchannel plate (MCP) double delay-line detector with dual solar-blind opaque photocathodes (KBr and CsI) and a focal surface that matches the instrument's 15-cm diameter Rowland-circle. In what follows, we describe the instrument in greater detail, including descriptions of its ground calibration and initial in flight performance.Comment: 24 pages, 29 figures, 2 tables; To appear in a special volume of Space Science Reviews on the New Horizons missio

Recovered memories, satanic abuse, Dissociative Identity Disorder and false memories in the UK: a survey of Clinical Psychologists and Hypnotherapists

An online survey was conducted to examine psychological therapists’ experiences of, and beliefs about, cases of recovered memory, satanic / ritualistic abuse, Multiple Personality Disorder / Dissociative Identity Disorder, and false memory. Chartered Clinical Psychologists (n=183) and Hypnotherapists (n=119) responded. In terms of their experiences, Chartered Clinical Psychologists reported seeing more cases of satanic / ritualistic abuse compared to Hypnotherapists who, in turn, reported encountering more cases of childhood sexual abuse recovered for the first time in therapy, and more cases of suspected false memory. Chartered Clinical Psychologists were more likely to rate the essential accuracy of reports of satanic / ritualistic abuse as higher than Hypnotherapists. Belief in the accuracy of satanic / ritualistic abuse and Multiple Personality Disorder / Dissociative Identity Disorder reports correlated negatively with the belief that false memories were possible

Intelligent Self-Organising Controllers for Autonomous Guided Vehicles: Comparative Aspects of Fuzzy Logic and Neural Nets

Of central importance to autonomous guided vehicles (AGVs) are the adaptive or intelligent tasks of:- (i) Multi-sensor data fusion or integration of sensory data for vehicle location, to represent or to model its internal states and its environment. (ii) Planning and navigation. (iii) Motion control. This paper addresses the last issue, motion controls that are vehicle dependent. Classical motion control is based upon deriving a set of vehicle model equations, and synthesising a set of feedback control laws. Unfortunately such an approach is limited only to constant velocity and environmental conditions and for small perturbations. Yet humans are able to generate driving algorithms with little physical insight, but with a great deal of experimental knowledge, this is flexible, robust, sufficiently precise for proper functioning, and intelligent, in that they adapt to differing environmental and payload conditions. This paper will review two approaches to AGV intelligent control adopted at Southampton, - (i) Self-organising fuzzy logic controllers (ii) associative memory type neural nets. Both approaches have the potential to provide real time adaptive convergent, robust decision strategies with little apriori knowledge. There are many similarities between the two approaches: (i) a transformed input space is required in both cases, (ii) Initial, approximate plant models are required, (iii) both adopt local weight/rule adaptation schemes - we also show an equivalence of learning through LMS based adaptation rules based upon B-splines, (v) both methods are extremely robust and fault tolerant

Coordination polymers: Opportunities and challenges for monitoring volatile organic compounds

Coordination polymers (CPs) are emerging as the next generation of macromolecules for many industrial and technological applications. The highly porous nature of these CPs offers the opportunity to exploit them as very effective adsorbents for gaseous molecules, including volatile organic compounds (VOCs). Release of VOCs into the environment is highly undesirable as they can be extremely harmful to general public health and environmental quality. Lately, a large volume of the scientific literature has pointed towards the potentially important role of CPs in the monitoring and analysis of VOCs, offering unprecedented detection limits. This review discusses the opportunities and challenges for the use of CP materials in such applications, describing their general working principles, analytical performance, advantages, and limitations. Recent progress in the application of CPs in the detection, monitoring, and analysis of VOCs is critically reviewed. The discussion is further extended to cover future applications and current research activities in this emerging analytical field