Which visualisation tools and why? Evaluating perceptions of student and practicing designers toward Digital Sketching

An ever-increasing array of design visualisation tools are available to designers. As such, design education is constantly challenged to keep up with these trends so that students are best equipped for entering industrial practice. This paper reports a study into the use of digital sketching, a relatively new digital visualisation tool. The study aims to identify thematic differences in how students and practitioners perceive digital sketching. These are given in terms of the tool’s characteristics, and how these characteristics guide its application in early stages of the design process. Data on perceptions is captured using design diaries and semistructured interviews. Results show key differences in the way that practitioners perceive the intent of visualisation. Practitioners focus on iterating towards a solution during the design process. Students are much more focused on the task of creating visualisations. This reveals an underlying contradiction in the way tools are perceived between creating visualisations to gain expertise or skill, versus creating them to advance the design process. The insights help improve our understanding of how the different characteristics of digital sketching inform its use. We reflect on how we educate students with respect to selecting and using digital sketching. We conclude with implications for education of digital sketching, as well as other emerging digital visualisation tools

Understanding Working Scenarios of Urban Air Mobility

Urban Air Mobility (UAM) can provide new air mobility faster and avoid city traffic with the growth of new technologies. But they need to be co-developed with the city infrastructure. Thus, understanding the working scenarios of UAM and how they will interact with the city and the other modes of transport systems is vital. Storyboarding helps policymakers, city planners, designers, and investors better understand the product's contextual interaction over time. This process allows the design team to be implicit or express a design that is easy to understand, reflect upon, or modify. © The Author(s), 2022

Outbursts of EX Hydrae Revisited

We present optical spectroscopy of EX Hya during its 1991 outburst. This outburst is characterised by strong irradiation of the front face of the secondary star by the white dwarf, an overflowing stream which is seen strongly in HeII and by a dip in the light curves, which extends from 0.1-0.6 in the binary and spin phases. Strong irradiation of the accretion curtain and that of the inner regions of the disc led to strong emission of HeII and to the suppression of the Hg and Hb emission. Disc overflow was observed in quiescence in earlier studies, where the overflow stream material was modulated at high velocities close to 1000 km/s. In outburst, the overflowing material is modulated at even higher velocities (~1500 km/s). These are streaming velocities down the field lines close to the white dwarf. Evidence for material collecting near the outer edge of the disc and corotating with the accretion curtain was observed. In decline, this material and the accretion curtain obscured almost all the emission near binary phase 0.4, causing a dip. The dip minimum nearly corresponds with spin pulse minimum. This has provided additional evidence for an extended accretion curtain, and for the corotation of material with the accretion curtain at the outer edge of the disc. From these observations we suggest that a mechanism similar to that of Spruit & Taam, where outbursts result due to the storage and release of matter outside the magnetosphere, triggers the outbursts of EX Hya. This is followed by the irradiation of the secondary star due to accretion induced radiation.Comment: 12 pages, 14 figures, 1 table. Figures 6, 7, 8 and 11 at low resolution. Paper accepted by the Monthly Notices of the Royal Astronomical Societ

X-ray confirmation of the intermediate polar HTCam

We report on the first pointed X-ray observations with XMM-Newton and RXTE satellites of the X-ray source RXJ0757.0+6306 = HT Cam. We detect a strong 515 s X-ray modulation confirming the optical photometric period found in 1998, which definitively assigns this source to the intermediate polar class of magnetic cataclysmic variables. The lack of orbital sidebands in the X-rays indicates that the X-ray period is the spin period of the accreting white dwarf. Simultaneous ultraviolet and optical B-band photometry acquired with the XMM-Newton Optical Monitor and coordinated optical UBVRI photometric data acquired at the Nordic Optical Telescope (La Palma) show that the optical pulse is in phase with the X-rays and hence originates in the magnetically-confined accretion flow. The lack of ultraviolet spin modulation suggests that accretion-induced heating on the white dwarf surface is not important in this source. Spectral analyses of XMM-Newton EPIC and RGS data show that HTCam has a multi-temperature spectrum and, contrary to most intermediate polars, it does not suffer from strong absorption. With its 86 min orbital period, HTCam is the third confirmed system of this class below the 2–3 h period gap accreting at a low rate

A precise HST parallax of the cataclysmic variable EX Hydrae, its system parameters, and accretion rate

Using the HST Fine Guidance Sensor, we have measured a high precision astrometric parallax of the cataclysmic variable EX Hydrae, pi=15.50+-0.29mas. From the wavelength-integrated accretion-induced energy flux, we derive a quiescent accretion luminosity for EX Hya of Lacc = (2.6+-0.6)x10e32 erg. The quiescent accretion rate then is Mdot=(6.2\+-1.5)x10e-11 (M1/0.5Msun)^(-1.61})Msun/yr. The time-averaged accretion rate, which includes a small correction for the rare outbursts, is 6% higher. We discuss the system parameters of EX Hya and deduce M1=0.4-0.7Msun, M2=0.07-0.10Msun, and i=76.0deg-77.6deg, using recent radial velocity measurements of both components and restrictions imposed by other observational and theoretical constraints. We conclude that the secondary is undermassive, overluminous, and expanded over a ZAMS star of the same mass. Near the upper limit to M1, the accretion rate of the white dwarf coincides with that due to near-equilibrium angular momentum loss by gravitational radiation and angular momentum transfer from the orbit into the spin-up of the white dwarf. Near the lower mass limit, the correspondingly higher accretion rate requires that either an additional angular momentum loss process is acting besides gravitational radiation or that accretion occurs on a near-adiabatic time scale. The latter possibility would imply that EX Hya is in a transient phase of high mass transfer and the associated spin-up of the white dwarf.Comment: 7 pages A&A-Latex, 1 Figure, accepted for publication in A&

Multi-wavelength spectrophotometry of EX Hydrae

We present phase-resolved infrared and optical spectrophotometry of the intermediate polar EX Hya supplemented by archival ultraviolet data. The spin-modulated emission from the accretion funnel and the emission from the accretion disk or ring contain substantial optically thin components. The white dwarf dominates the unmodulated flux in the ultraviolet and is identified by numerous absorption lines. Metal absorption in the accretion curtain may add to the observed spectral features. The secondary star is of spectral type M4+-1 and is detected by its ellipsoidal modulation. We derive a distance of 65+-11 pc which makes EX Hydrae one of the closest cataclysmic variables with a known distance. The luminosity derived from the integrated overall spectral energy distribution is 3x10^32 erg/s. The accretion rate of 3x10^15 g/s (for an 0.6 Msun white dwarf) is in reasonable agreement with the rates expected from angular momentum loss by gravitational radiation and from the observed spin-up of the white dwarfComment: 15 A&A Latex, 9 Figures, accepted for publication in A&

USERS’ SURVEY FOR DEVELOPMENT OF PASSENGER DRONES

The prosperity of any megacities heavily depends on smooth transport systems. In India, however, most cities are failing to keep in step with the growing demands. With new technologies, such as passenger drones, an alternate mode of intra-city transportation seems within reach. For successful development of passenger drones in a diverse country like India, understanding users' needs are vital. This paper presents the results from a survey of potential users of passenger drones from across India. These are then used to derive concrete recommendations for passenger drones design parameters