A sports headlight retrofitted on magnifying loupes: A simple and cheap method for daily use

Medical professionals such as doctors, nurses and paramedics often use headlight to examine or to perform surgical intervention in the patients. However, there are concerns related to its use such as comfort for the user, mobility and asepsis for the cable, availability in the departments plus cost effectiveness. The concept of a retrofitted 1-watt sports headlight (adjusted on magnifying loupes) would give quick access to a light source, be available and reliable at any place, save vital funds and would be environmentally friendly as the battery can be replaced. The same concept can be applied to pre-hospital emergency care and disaster medicine as well. BACKGROUND Headlights with fibre optic cables have being used for two decades as an adjunct to the operating theatre lighting. The cable-powered headlights pose, to our experience, some limitations for the operating team: Smooth personnel circulation around the operating field is hindered by repeated unplugging and re-plugging of the cable when surgeon and assistants change sides. Protocols for draping and asepsis have to accommodate the cumbersome cable and the light source and in addition are time consuming and arising issues of flexibility. The weight of the headlight and cable may cause health issues for the bearer (head ache, low back pain) [1]. Portable surgical headlights have also been available for the last decade for a not negligible cost. They are powered by a battery pack, attached to the torso/waist and connected to the headlight by a shorter cable. They are priced at hundreds of pounds. METHOD As an alternative to cumbersome cables and expensive ‘ad hoc’ designs, we use a retrofitted 1-watt sports headlight with a weight of 100 grams. We acquired that for $ 14.99 (approximately £10) from an outdoor specialist retailer (Petzl America, Clearfield, Utah, USA). The headlight is powered by three 1.5 Volt AAA batteries and provides 60 lumen of luminous flux (Fig.1). We have wrapped the elastic bands of the headlight around the corresponding horizontal (axial circumferential) and sagittal elements of the headband, where the magnifying loupes are mounted (Keeler Ltd., Clewer Hill Road, Windsor SL4 4AA). The headlight can be aimed by tilting the housing (Fig.1, 2). DISCUSSION The luminous flux from our headlight according to our experience in cardiothoracic surgery is adequate for a variety of procedures: femoral and axillary arterial access, harvesting internal thoracic (mammary) arteries, open pulmonary resections, valve surgery. Being fully portable without cable, light source or pouches, it is especially handy outside the operating suite (ITU, A&E, wards) for emergency re-explorations for bleeding, secondary wound closures, application of vacuum therapy dressings, trauma, for ECMO work etc. Finally, we have had no evidence of thermal injury, as has being reported from strong xenon beams [2]. This simple affordable headlight system can be easily adapted to the needs of the entire spectrum of surgical specialties, especially those using magnifying loupes. Therefore, can be part of basic life support kits for use in prehospital emergency care, disaster and military medicine [3]. The device has the following advantages: 1. ‘‘Two-in-one’’ function of Loupes and Torch. 2. Battery can be changed (so no need to throw away the item) and is environmentally friendly 3. No need for asepsis 4. Cost effective 5. Availability everywhere In conclusion, we believe this is a practical medical device

How does identity influence creative photography

The purpose of this research project was to explore the origins of the photographer’s identity and how this is evidenced in his/her photographic work. The findings and conclusions derived from this examination were assessed in terms of their relevance and value for photography in education in order to contribute to an innovative theoretical approach for reading, understanding and analysing a photograph. The study’s aim has been to identify significant connections between the photographer’s identity and his/her photographic work and develop an innovative framework based on teaching photography as an art form comparable to Fine Art. Finally, it merged the two fields of my interest in teaching and practicing photography in a multi-phase action based experience. In order to build on an innovative approach to the teaching of photography, this study drew on several theories, concepts and ideas related to philosophy and the theoretical analysis of photography within current discourses. The results illuminated that there is no literature review on the relation of photography with the artist’s identity in analysing a photograph either in English or Greek sources. This art and education research process was conducted under the practice-based methodology of A/r/tography. Through this methodology I was implicated in three different roles, those of the artist, the researcher and the teacher, and linked them with their actual function within the project process (Irwin, 2006). As an artist I observed the participants’ actions, behaviours and situations within their environment and private space and gathered information about their real life experiences and knowledge that constructed their identity and influenced their creative work. As a researcher I collected all the necessary material from literature review as well as the participants’ real life and work settings. Finally, my role as a researcher-teacher was to analyse and evaluate the findings and come to the conclusion of the approach for teaching photography to the students. As a part of the research, eight contemporary photographers (including the self-agent) were interviewed. The sample comprised of four Cypriot and four Greek professional photographers. I was the only participant who was also a teacher. All participants were selected after evaluating the evidence of their identity in their personal work. During evaluation I considered any information about the artists that suggested any influence of their identity in their images. The findings of the participants’ interviews linked and correlated with the literature review filled the scholarly gap about the construction of identity and its influence on the photographer’s inspiration and creative work. This new line of thought suggested a need to revise the syllabus in photography education not only to the basic principles of photography but also to reading, understanding and analysing a photograph. This awareness has led to an innovative framework for teaching photography

Magnetic levitation of large liquid volume

It is well known from experiments and industrial applications of cold crucible melting that an intense AC magnetic field can be used to levitate large volumes of liquid metal in the terrestrial conditions. The levitation confinement mechanism for large volumes of fluid is considerably different from the case of a small droplet, where surface tension plays a key role in constraining the liquid outflow at the critical bottom point. The dynamic interaction between the oscillatory motion of the free surface and the effects of turbulent flow is analysed using a unified numerical model, which describes the time dependent behaviour of the liquid metal and the magnetic field. The MHD modified k-? turbulence model is used to describe the mixing and damping properties at smaller scales not resolved by the macro model. The numerical multiphysics simulations suggest that it is possible to levitate a few kilograms of liquid metal in a cold crucible without requiring mechanical support from the container walls. Possible applications to the processing of reactive metals are discussed

Use of a Static Magnetic Field in Measuring the Thermal Conductivity of a Levitated Molten Droplet

Numerical models are used to analyze the complex behaviour of magnetically levitated droplets in the context of determining their thermophysical properties. We focus on a novel method reported in Tsukada et al. [4] which uses periodic laser heating to determine the thermal conductivity of an electromagnetically levitated droplet in the presence of a static DC field to suppress convection. The results obtained from the spectral-collocation based free surface code SPHINX and the commercial package COMSOL independently confirm and extend previous findings in [4]. By including the effects of turbulence and movement of the free surface SPHINX can predict the behaviour of the droplet in dynamic regimes with and without the DC magnetic field. COMSOL is used to investigate arbitrary amplitude axial translational oscillations when the spherical droplet is displaced off its equilibrium. The results demonstrate that relatively small amplitude oscillations could cause significant variation in Joule heating and redistribution of the temperature. The effect of translational oscillations on the lumped circuit inductance is analysed. When a fixed voltage drive is applied across the terminals of the levitation coil, this effect will cause the coil current to change and a correction is needed to the electromagnetic force acting on the droplet

An oscillatory turbulent boundary layer in an adverse pressure gradiant.

PhDA turbulent boundary layer experiencing a time mean adverse pressure gradient and a controllable travelling wave periodic oscillation, was examined experimentally. An open return low speed wind-tunnel with a semi-open working section was used for this purpose, with oscillating flaps at its exit inducing the oscillations. The boundary layer on a specially designed "S" shaped model of chord 2m and thickness/ chord ratio of3.6%was investigated, for a range of frequencies from 1 to 6Hz, and amplitudes of the order of 10% of the time mean freestream velocity. The turbulent boundary layer evolved naturally around x/c= . 23, and measurements were taken for a Reynolds number Rec=3401. The effect of flap amplitude was examined for a range of amplitudes, from 2 to 4 inches. Unsteady velocity and pressure quantities were measured using Hot-wire techniques and pressure transducers, with the aid of a digital sampling system. Boundary layer mean values, were found to be invýriant with both frequency and amplitude of oscillation, while unsteady components were predominantly affected by frequency and downstream position but not amplitude. Unsteady velocities in the boundary layer lagged the freestream oscillations by as much as 1500 in some cases, while amplitudes exceeded freestream values by as much as 70

Numerical modelling of liquid droplet dynamics in microgravity

Microgravity provides ideal experimental conditions for studying highly reactive and under-cooled materials where there is no contact between the sample and the other experimental apparatus. The non-contact conditions allow material properties to be measured from the oscillating liquid droplet response to perturbations. This work investigates the impact of a strong magnetic field on these measurement processes for weakly viscous, electrically conducting droplets. We present numerical results using an axisymmetric model that employs the pseudo-spectral collocation method and a recently developed 3D model. Both numerical models have been developed to solve the equations describing the coupled electromagnetic and fluid flow processes. The models represent the changing surface shape that results from the interaction between forces inside the droplet and the surface tension imposed boundary conditions. The models are used to examine the liquid droplet dynamics in a strong DC magnetic field. In each case the surface shape is decomposed into a superposition of spherical harmonic modes. The oscillation of the individual mode coefficients is then analysed to determine the oscillation frequencies and damping rates that are then compared to the low amplitude solutions predicted by the published analytical asymptotic theory

TEMHD Effects on Solidification Under Microgravity Conditions

An unexplored potential exists to control microstructure evolution through the use of external DC magnetic fields. Thermoelectric currents form during solidification and interact with this external field to drive microscopic fluid dynamics within the inter-dendritic region. The convective heat and mass transport can lead to profound changes on the dendritic structure. In this paper the effect of high magnetic fields is demonstrated through the use of both 3-dimensional and 2-dimensional numerical models. The results show that the application of a magnetic field causes significant disruption to the dendritic morphology. Investigation into the underlying mechanism gives initial indicators of how external magnetic fields can either lead to unexpected growth behaviour, or alternatively can be used to control the evolution of microstructure in undercooled melts as encountered in levitated droplet solidification