Novel concept for full‐color electronic paper

Abstract— Despite a steep increase in commercial devices comprising paper‐like displays, a much desired feature is still missing: bright full‐color electronic paper. A new reflective‐display technology has been developed to solve this issue. For the first time, the principles behind this in‐plane electrophoretic technology will be presented, which enables the realization of full‐color reflective displays with a higher brightness than presently available e‐paper technologies, without compromising paper‐like properties such as viewing angle and ultra‐low power consumption. An additional major advantage (e.g., for future low‐cost manufacturing) is that, besides direct‐drive and active‐matrix configurations, a passive‐matrix option with analog gray levels has been successfully developed.     

Load on the lumbar spine of flight attendants during pushing and pulling trolleys aboard aircraft

Flight attendants report on high physical load and complaints particularly focussing on the lower back. These findings are mainly ascribed to pushing and pulling of trolleys during the ascent and descent flight phases. Within an interdisciplinary experimental study, the load on the lumbar spine of flight attendants during trolley handling aboard aircraft was analysed based on laboratory measurements regarding posture and exerted forces as well as on subsequent biomechanical model calculations. Forces and moments of force at the lumbosacral disc were quantified for 458 manoeuvres performed by 25 flight attendants in total (22 female, 3 male).Lumbar load varies according to handling mode (pushing, pulling), floor gradient (0°, 2°, 5°, 8°), trolley type (half-, full-size trolley), trolley loading (empty, medium, full) and, in addition, according to individual execution technique. For each of the resulting 48 task configurations, lumbar load was evaluated with respect to potential biomechanical overload by applying work-design recommendations for disc compression and moment of force. Irrespective of floor inclination, trolley weight and individual performance, pushing of small trolleys is combined with acceptable lumbar load, pulling with critical load. Pushing or pulling large trolleys occasionally yield to critical lumbar load, in particular, when heavy or heaviest containers are moved on relatively steep or steepest surfaces.To diminish overload risk relevantly, top-edge grasp positions should be avoided for pulling of half-size trolleys, whereas for the other cases, grasping at the upper edge of the trolley is recommended.

Relevance to industry

The provided study illustrates lumbar load of flight attendants during trolley handling aboard aircraft for typical task conditions and individual execution techniques. Specified hints for work design regarding posture and grasp position enable to avoid biomechanical low-back overload for flight attendants. Furthermore, trolley properties may be reconsidered, regular maintenance of rollers should be guaranteed.     

Metal‐Halide Perovskites for Gate Dielectrics in Field‐Effect Transistors and Photodetectors Enabled by PMMA Lift‐Off Process

Metal‐halide perovskites have emerged as promising materials for optoelectronics applications, such as photovoltaics, light‐emitting diodes, and photodetectors due to their excellent photoconversion efficiencies. However, their instability in aqueous solutions and most organic solvents has complicated their micropatterning procedures, which are needed for dense device integration, for example, in displays or cameras. In this work, a lift‐off process based on poly(methyl methacrylate) and deep ultraviolet lithography on flexible plastic foils is presented. This technique comprises simultaneous patterning of the metal‐halide perovskite with a top electrode, which results in microscale vertical device architectures with high spatial resolution and alignment properties. Hence, thin‐film transistors (TFTs) with methyl‐ammonium lead iodide (MAPbI₃) gate dielectrics are demonstrated for the first time. The giant dielectric constant of MAPbI₃ (>1000) leads to excellent low‐voltage TFT switching capabilities with subthreshold swings ≈80 mV decade^?1 over ≈5 orders of drain current magnitude. Furthermore, vertically stacked low‐power Au‐MAPbI₃‐Au photodetectors with close‐to‐ideal linear response (R² = 0.9997) are created. The mechanical stability down to a tensile radius of 6 mm is demonstrated for the TFTs and photodetectors, simultaneously realized on the same flexible plastic substrate. These results open the way for flexible low‐power integrated (opto‐)electronic systems based on metal‐halide perovskites.     

Light diffusion through a turbid parallelepiped

Solutions of the diffusion approximation to the radiative transport equation are derived for a turbid (rectangular) parallelepiped using the method of image sources and applying extrapolated boundary conditions. The derived solutions are compared with Monte Carlo simulations in the steady-state and time domains. It is found that the diffusion theory is in good agreement with Monte Carlo simulations provided that the light is detected sufficiently far from the incident beam. Applications of the derived solutions, including the determination of the optical properties of the turbid parallelepiped, are discussed.     

Assessing the validity of the achievement motive in the presence of random measurement error.

The presence of random measurement error in indicators of theoretical constructs biases observed estimates of relations among those constructs. Correcting for this bias is particularly important when random measurement error is substantial or is substantially different for indicators of distinct constructs included in a theoretical model. Validity assessment in the case of thematic apperceptive measures of the achievement motive (TAT n Achievement) has been vulnerable to interpretive errors because these indicators of the achievement motive are typically much less reliable than indicators of other constructs to which the motive may be related, and no correction has been made for the bias introduced by such differential measurement error. A causal modeling approach to validity assessment for TAT n Achievement is presented that incorporates explicit true-score measurement models of theoretical constructs. Data from J. Veroff et al (1981) on 413 adult US males confirm the hypothesis that the achievement motive construct is positively related to work satisfaction. Evidence for the discriminant validity of story content as opposed to story length, an issue raised in the literature on the TAT, is also presented in this nomological network. (56 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)