Automated static magnetic cleanliness screening for the TRACERS small-satellite mission

The Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites (TRACERS) Small Explorers mission requires high-fidelity magnetic field measurements for its magnetic reconnection science objectives and for its technology demonstration payload Magnetometers for Innovation and Capability (MAGIC). TRACERS needs to minimize the local magnetic noise through a magnetic cleanliness program such that the stray fields from the spacecraft and its instruments do not distort the local geophysical magnetic field of interest. Here we present an automated magnetic screening apparatus and procedure to enable technicians to routinely and efficiently measure the magnetic dipole moments of potential flight parts to determine whether they are suitable for spaceflight. This procedure is simple, replicable, and accurate down to a dipole moment of 1.59 × 10−3 N m T−1. It will be used to screen parts for the MAGIC instrument and other subsystems of the TRACERS satellite mission to help ensure magnetically clean measurements on orbit.</p

Modelling curved-layered printing paths for fabricating large-scale construction components

In this paper, a non-conventional way of additive manufacturing, curved-layered printing, has been applied to large-scale construction process. Despite the number of research works on Curved Layered Fused Deposition Modelling (CLFDM) over the last decade, few practical applications have been reported. An alternative method adopting the CLFDM principle, that generates a curved-layered printing path, was developed using a single scripting environment called Grasshopper – a plugin of Rhinoceros® . The method was evaluated with the 3D Concrete Printing process developed at Loughborough University. The evaluation of the method including the results of simulation and printing revealed three principal benefits compared with existing flat-layered printing paths, which are particularly beneficial to large-scale AM techniques: (i) better surface quality, (ii) shorter printing time and (iii) higher surface strengths

Form finding of twisted interlaced structures: a hybrid approach

Our study presents a set of form-finding procedures to explore curved structures made from interlaced panels. Interlacing introduces a particular coupling between assembly components which has to be formulated along with a pertinent flexible body model. We examine here a hybrid approach: panels are simulated a first time using an elastic rod model formulated within a constrained elastic energy minimization where user can virtually buckle, twist and interlace strip assemblies. A thin shell model dynamically integrated comes complementary to the rod approach in order to resolve intersections in case of panels colliding while interlaced. Some conceptual structures are presented to demonstrated the procedure

Biomorpher: interactive evolution for parametric design

Combining graph-based parametric design with metaheuristic solvers has to date focussed solely on performance based criteria and solving clearly defined objectives. In this paper, we outline a new method for combining a parametric modelling environment with an interactive Cluster-Orientated Genetic Algorithm (COGA). In addition to performance criteria, evolutionary design exploration can be guided through choice alone, with user motivation that cannot be easily defined. As well as numeric parameters forming a genotype, the evolution of whole parametric definitions is discussed through the use of genetic programming. Visualisation techniques that enable mixing small populations for interactive evolution with large populations for performance-based optimisation are discussed, with examples from both academia and industry showing a wide range of applications

Design agency:prototyping multi-agent systems in architecture

This paper presents research on the prototyping of multi-agent systems for architectural design. It proposes a design exploration methodology at the intersection of architecture, engineering, and computer science. The motivation of the work includes exploring bottom up generative methods coupled with optimizing performance criteria including for geometric complexity and objective functions for environmental, structural and fabrication parameters. The paper presents the development of a research framework and initial experiments to provide design solutions, which simultaneously satisfy complexly coupled and often contradicting objectives. The prototypical experiments and initial algorithms are described through a set of different design cases and agents within this framework; for the generation of façade panels for light control; for emergent design of shell structures; for actual construction of reciprocal frames; and for robotic fabrication. Initial results include multi-agent derived efficiencies for environmental and fabrication criteria and discussion of future steps for inclusion of human and structural factors

Gender differences in patients with dizziness and unsteadiness regarding self-perceived disability, anxiety, depression, and its associations

BACKGROUND: It is known that anxiety and depression influence the level of disability experienced by persons with vertigo, dizziness or unsteadiness. Because higher prevalence rates of disabling dizziness have been found in women and some studies reported a higher level of psychiatric distress in female patients our primary aim was to explore whether women and men with vertigo, dizziness or unsteadiness differ regarding self-perceived disability, anxiety and depression. Secondly we planned to investigate the associations between disabling dizziness and anxiety and depression. METHOD: Patients were recruited from a tertiary centre for vertigo and balance disorders. Participants rated their global disability as mild, moderate or severe. They filled out the Dizziness Handicap Inventory and the two subscales of the Hospital Anxiety Depression Scale (HADS). The HADS was analysed 1) by calculating the median values, 2) by estimating the prevalence rates of abnormal anxiety/depression based on recommended cut-off criteria. Mann-Whitney U-tests, Chi-square statistics and odds ratios (OR) were calculated to compare the observations in both genders. Significance values were adjusted with respect to multiple comparisons. RESULTS: Two-hundred and two patients (124 women) mean age (standard deviation) of 49.7 (13.5) years participated. Both genders did not differ significantly in the mean level of self-perceived disability, anxiety, depression and symptom severity. There was a tendency of a higher prevalence of abnormal anxiety and depression in men (23.7%; 28.9%) compared to women (14.5%; 15.3%). Patients with abnormal depression felt themselves 2.75 (95% CI: 1.31-5.78) times more severely disabled by dizziness and unsteadiness than patients without depression. In men the OR was 8.2 (2.35-28.4). In women chi-square statistic was not significant. The ORs (95% CI) of abnormal anxiety and severe disability were 4.2 (1.9-8.9) in the whole sample, 8.7 (2.5-30.3) in men, and not significant in women. CONCLUSIONS: In men with vertigo, dizziness or unsteadiness emotional distress and its association with self-perceived disability should not be underestimated. Longitudinal surveys with specific pre-defined co-variables of self-perceived disability, anxiety and depression are needed to clarify the influence of gender on disability, anxiety and depression in patients with vertigo, dizziness or unsteadiness

Role of age and middle ear transmission characteristics in the frequency tuning of cVEMP and oVEMP

Project Description Ageing causes a decline in the functioning of most sensory systems, including the vestibular system. Decrements in vestibular function are an independent risk factor for falling. Therefore, there is a need for efficient vestibular diagnostic tests that identify clinically meaningful vestibular impairments in older patients. Background: Age related degenerative changes of the vestibular system occur in the vestibular end organs as well as the central vestibular structures. The vestibular end organs: saccule and utricle can be assessed using cervical evoked myogenic potential (cVEMP) and ocular vestibular evoked myogenic potential (oVEMP) respectively. The cVEMP and oVEMP are some of the most widely used vestibular diagnostic assessments; however previous works have showed that both responses, when elicited using a conventional and widely used stimulus of 500 Hz, are often bilaterally absent in older adults yielding results that are difficult to interpret. Therefore, there is a need to identify a stimulus that could best assess the older adult’s saccular and utricular functioning. Objective and methods: The purpose of this study was: 1) to assess age-related changes on various stimuli that can be used to assess cVEMP and oVEMP, and 2) to determine the optimal stimulus frequency in the young adult, middle age, and older adult populations. Additionally, we performed middle ear evaluation, to delineate age related changes in the middle ear from changes occurring in the inner ear of balance. A total of 107 participants consented to be in the study. Participants were divided in three groups: young adults (18-30 years), middle aged adults (41-59 years) and older adults (60-80 years). All of the participants underwent cVEMP and oVEMP testing using 500 Hz, 750 Hz and 1000 Hz air conducted stimuli. Middle ear functioning was also calculated for each of the participants. Results and Conclusion: It was found that age did not cause any change in measures of middle ear functioning. However, age did alter the saccular (cVEMP) and utricular (oVEMP) responses and this age effect was dependent on the stimulus frequency. The strength/amplitude of the cVEMP decreased with increasing age for the more conventional frequency (500 Hz), but the age effect was not observed at the higher frequency of 1000 Hz. Further, for the older adults, cVEMP was largest in amplitude and more often present at 1000 Hz. This differed from the young adult group where 500 Hz was the best frequency to elicit a cVEMP. For the oVEMP, the strength/amplitude decreased with increasing age for all the three stimuli/frequencies and the best stimulus frequency in all the three age groups was 1000 Hz. We also found that middle ear did not contribute towards shaping the response of cVEMP and oVEMP for various stimuli. Thus, the changes in the cVEMP and oVEMP frequency tuning observed in the older adults may not be stemming from middle ear but could be due to age related changes in the vestibular system

The influence of Titan on Saturn kilometric radiation

Previous studies have shown that the occurrence probability of Saturn Kilometric Radiation (SKR) appears to be influenced by the local time of Titan. Using a more extensive set of data than the original study, we confirm the correlation of higher occurrence probability of SKR when Titan is located near local midnight. In addition, the direction finding capability of the Cassini Radio Plasma Wave instrument (RPWS) is used to determine if this radio emission emanates from particular source regions. We find that most source regions of SKR are located in the mid-morning sector of local time even when Titan is located near midnight. However, some emission does appear to have a source in the Saturnian nightside, consistent with electron precipitation from field lines that have recently mapped to near Titan