Guest editorial : girls' and women's participation in STEM : past lessons and possible futures

Although the presence of women and girls in many Science, Technology, Engineering, and Mathematics (STEM) fields has increased in recent decades, women remain underrepresented in STEM in comparison to men (Watt, 2010). Structures and processes that compromise women and girls’ entry to and advancement in STEM fields (e.g., cultural messages, see Halpern, Benbow, Geary, Gur, Hyde & Gernsbacher, 2007) appear to per sist despite historical evidence of female ability and competence in STEM (OECD, 2015). The current Special Issue 'Girls' and women's participation in STEM: Past lessons and possible futures’, foregrounds the need for vigilance in ensuring equitable STEM opportunities for women and girls, in the light of historical events. However, the Special Issue also reports evidence and approaches that offer forward momentum in addressing inequitable opportunity and promoting futures for women and girls, in a diversity of STEM fields

Tackling the teacher shortage – near-peer mentoring of STEM students for outreach and engagement using trainee teachers

This poster outlines a pilot scheme for delivering CPD training to undergraduate STEM students, utilising trainee science teachers as “near-peer” mentors to enhance student volunteers’ ability to undertake science outreach activities in local schools and the wider community. The driving force for this project is to tackle the teacher shortage in STEM subjects, which it is hoped can be achieved in a number of ways. The trainee teachers themselves will develop their professional skills by acting as mentors while STEM students will become more closely engaged with the profession, current pedagogy and young people within schools. This effectively serves as a marketing tool which potentially increases the likelihood of these students applying for Initial Teacher Training (ITT). Finally, the long-term goal is to enhance children’s enthusiasm for science at an early stage, with a view to widening participation and improving uptake of STEM subjects at A-level and in Higher Education – nurturing the interest and talent of a future generation of teachers

The impact of ‘bursary tourism’ or the desire for a ‘fulfilling, challenging, and emotionally rewarding career’? Career entry motivations and perceptions of preservice teachers from England

Why teachers choose their career has been a popular topic of research in many contexts since the introduction of the FIT-Choice framework by Watt and Richardson in 2007 to study teacher motivations. Although altruistic motivations have been identified as the common driving factor behind preservice teachers' (PSTs') decision to enter the field, there are other motivational factors—such as teaching being a career that fits well with family commitments, or choosing teacher education as a ‘fallback’ option—that are widely reported in different contexts. The introduction of incentives for student teachers in certain subjects has been subject to media criticism in England as promoting ‘bursary tourism’. This study investigates the career entry motivations and teaching perceptions of PSTs from a university that is one of the key teacher education providers in the country, using the FIT-Choice framework. The paper discusses the findings (N = 115), including validation of the FIT-Choice scale, collecting data on 12 motivations and six perceptions, along with preliminary findings. It was identified that intrinsic career values were the highest rated motivation, followed by altruistic values such as the desire to make a social contribution and being a part of shaping the future of children and adolescents. Perceived abilities were also rated higher, while personal utility values and task returns— including monetary rewards—were rated very low. While the participants agreed that the job is professionally and emotionally demanding, it was promising to note that they were highly satisfied with their career choice, implicitly indicating their intention to continue in the teaching profession. Gender differences, along with field of study and training pathway differences in motivations and teaching perceptions are also discussed, with practical implications

Mathematical principles for the design of isostatic mount systems for dynamic structures

Isostatic mounts are used in applications like telescopes and robotics to move and hold part of a structure in a desired pose relative to the rest, by driving some controls rather than driving the subsystem directly. To achieve this successfully requires an understanding of the structure of the coupled space of configurations and controls, and of the singularities of the mapping from the coupled space to the space of controls. It is crucial to avoid such singularities because generically they lead to large constraint forces and internal stresses which can cause distortion. In this paper we outline design principles for isostatic mount systems for dynamic structures, with particular emphasis on robots

Inconsistency of threat level in soft armour standards, correlation of experimental tests to bullet X-ray 3D images

Fundamental to any ballistic armour standard is the reference projectile that is to be defeated. Typically, for certification, consistency of bullet geometry is assumed. Therefore, practical variations in bullet jacket dimensions can have far reaching consequences. Traditionally, internal dimensions have been analysed by physically sectioning bullets – an approach which rules out any subsequent ballistic assessment. The use of a non-destructive X-ray Computed Tomography (CT) method was demonstrated in [1]. Now, the authors apply this technique to correlate bullet impact response to jacket thickness variations. A set of 20 bullets (9 mm DM 11) was selected to analyse both intra and inter bullet variations using an image based analysis method to map the jacket thickness and measure the centre of gravity. Thickness variations of the order of 200μm were found commonly across all the bullets along the length and an angular variation of up to 50μm was found in a few bullets. The bullets were subsequently impacted against a rigid flat plate and re-scanned. The results of the experiments are shown and compared to the un-deformed bullet jacket thickness variations. The conclusions are relevant for future soft armour standards and provide important data for numerical model correlation and development

Simulation, modelling and development of the metris RCA

In partnership with Metris UK we discuss the utilisation of modelling and simulation methods in the development of a revolutionary 7-axis Robot CMM Arm (RCA). An offline virtual model is described, facilitating pre-emptive collision avoidance and assessment of optimal placement of the RCA relative to scan specimens. Workspace accessibility of the RCA is examined under a range of geometrical assumptions and we discuss the effects of arbitrary offsets resulting from manufacturing tolerances. Degeneracy is identified in the number of ways a given pose may be attained and it is demonstrated how a simplified model may be exploited to solve the inverse kinematics problem of finding the “correct” set of joint angles. We demonstrate how the seventh axis may be utilised to avoid obstacles or otherwise awkward poses, giving the unit greater dexterity than traditional CMMs. The results of finite element analysis and static force modelling on the RCA are presented which provide an estimate of the forces exerted on the internal measurement arm in a range of poses

Characteristics, accuracy and reverification of robotised articulated arm CMMs

VDI article 2617 specifies characteristics to describe the accuracy of articulated arm coordinate measuring machines (AACMMs) and outlines procedures for checking them. However the VDI prescription was written with a former generation of machines in mind: manual arms exploiting traditional touch probe technologies. Recent advances in metrology have given rise to noncontact laser scanning tools and robotic automation of articulated arms – technologies which are not adequately characterised using the VDI specification. In this paper we examine the “guidelines” presented in VDI 2617, finding many of them to be ambiguous and open to interpretation, with some tests appearing even to be optional. The engineer is left significant flexibility in the execution of the test procedures and the manufacturer is free to specify many of the test parameters. Such flexibility renders the VDI tests of limited value and the results can be misleading. We illustrate, with examples using the Nikon RCA, how a liberal interpretation of the VDI guidelines can significantly improve accuracy characterisation and suggest ways in which to mitigate this problem. We propose a series of stringent tests and revised definitions, in the same vein as VDI 2617 and similar US standards, to clarify the accuracy characterisation process. The revised methodology includes modified acceptance and reverification tests which aim to accommodate emerging technologies, laser scanning devices in particular, while maintaining the spirit of the existing and established standards. We seek to supply robust re-definitions for the accepted terms “zero point” and “useful arm length”, pre-supposing nothing about the geometry of the measuring device. We also identify a source of error unique to robotised AACMMs employing laser scanners – the forward-reverse pass error. We show how eliminating this error significantly improves the repeatability of a device and propose a novel approach to the testing of probing error based on statistical uncertainty

Additive manufacture of impedance matching layers for air-coupled ultrasonic transducers

A key problem in designing an efficient ultrasonic transducer for operating in a low acoustic impedance medium such as air is the large impedance mismatch between the active piezoceramic material and the load medium. While acoustic matching layers can be added to the face of the piezoceramic, the associated manufacturing difficulties and reliability can impact upon the cost and longevity of the resultant transducer. This paper presents some preliminary investigations conducted using an additive manufacturing technique, to develop a new material system for matching layer fabrication for air-coupled ultrasonic transducers. Results to date are very encouraging, and could result in a robust, reproducible, economical and improved fabrication method for air-coupled transducers