Physical and electrochemical properties of cobalt doped (Ti,Ru)O2 electrode coatings

The physical and electrochemical properties of ternary oxides Ti_0.7Ru_0.3−xCo_xO₂ (x = 0.093 and x = 0) have been investigated and compared. Samples of three different thicknesses were prepared by spin-coating onto polished titanium to achieve uniform and well-defined coatings. The resulting electrodes were characterized with a variety of methods, including both physical and electrochemical methods. Doping with cobalt led to a larger number of micrometer-sized cracks in the coating, and coating grains half the size compared to the undoped samples (10 instead of 20 nm across). This is in agreement with a voltammetric charge twice as high, as estimated from cyclic voltammetry. There is no evidence of a Co₃O₄ spinel phase, suggesting that the cobalt is mainly incorporated in the overall rutile structure of the (Ti,Ru)O₂. The doped electrodes exhibited a higher activity for cathodic hydrogen evolution compared to the undoped electrodes, despite the fact that one third of the active ruthenium was substituted with cobalt. For anodic chlorine evolution, the activity was similar for both electrode types.     

Pulse contour-derived cardiac output in hemodialysis patients

Reliable methods for cardiac output determination are essential for studying the pathophysiology of intradialytic hypotension. Use of the current gold standard, the Transonic^® monitor, requires an arteriovenous fistula. We wished to verify the accuracy of a method based on finger pulse contour analysis, namely the Finometer^® monitor (FNM) for further use on patients dialyzing on a central vascular catheter. Fifty simultaneous cardiac output measurements were obtained during hemodialysis sessions in 25 patients. The internal variability of the FNM measurements was assessed by comparing 24 pairs of immediately successive measurements. The variability of successive FNM measurements was small (bias 0.28%, SD ± 6.1%; NS). The absolute cardiac output values reported by the FNM were unreliable (bias 20.1%, SD ± 35.3%; P<0.001) as were the relative intradialytic changes (r²=0.01). Excluding participants from the analysis due to old age, high dialysis vintage or a suspicion of atherosclerosis did not improve the results. Our findings do not support the use of pulse contour analysis for measuring cardiac output in hemodialysis patients. Uremic vascular disease may be the cause of the observed inaccuracy.     

Quasi-static behaviour of composite joints with protruding-head bolts

An experimental study of the quasi-static behaviour of composite bolted joints under tensile and compressive loading has been performed. The joint plates made of quasi-isotropic and 0°-dominated lay-ups were fastened by two, four, or six titanium bolts. Two specimen configurations were tested: single lap and double lap. Strain gauges were applied in order to measure strain between the bolt rows and to calculate the load transfer of the bolt rows. Bolt-movement measurements were performed using extensometers to examine bolt behaviour under static loading. The obtained experimental results showed that bolted joints with four and six bolts perform better resistance to quasi-static loading than joints with two bolts. Strain distribution between two bolts is significantly affected by the bolt presence and their behaviour under loading. The load-transfer calculations showed that different bolt rows transfer slightly different amounts of load.     

Chemical composition and mass emission factors of candle smoke particles

The aim of this study is to investigate the physical and chemical properties of particle emissions from candle burning in indoor air. Two representative types of tapered candles were studied during steady burn, sooting burn and smouldering (upon extinction) under controlled conditions in a walk-in stainless steel chamber. Steady burn emits relatively high number emissions of ultrafine particles dominated by either phosphates or alkali nitrates. The likely source of these particles is flame retardant additives to the wick. Sooting burn in addition emits larger particles mainly consisting of agglomerated elemental carbon. This burning mode is associated with the highest mass emission factors. Particles emitted during smouldering upon extinction are dominated by organic matter. A mass closure was illustrated for the total mass concentration, the summed mass concentration from chemical analysis and the size-integrated mass concentration assessed from number distribution measurements using empirically determined effective densities for the three particle types.     

A computationally convenient unit root test with covariates,conditional heteroskedasticity and efficient detrending

When testing for a unit root in a time series, in spite of the well‐known power problem of univariate tests, it is quite common to use only the information regarding the autoregressive behaviour contained in that series. In a series of influential papers, Elliott et al. (Efficient tests for an autoregressive unit root, Econometrica 64, 813–836, 1996), Hansen (Rethinking the univariate approach to unit root testing: using covariates to increase power, Econometric Theory 11, 1148–1171, 1995a) and Seo (Distribution theory for unit root tests with conditional heteroskedasticity, Journal of Econometrics 91, 113–144, 1999) showed that this practice can be rather costly and that the inclusion of the extraneous information contained in the near‐integratedness of many economic variables, their heteroskedasticity and their correlation with other covariates can lead to substantial power gains. In this article, we show how these information sets can be combined into a single unit root test.     

ADAS at work: assessing professional bus drivers’ experience and acceptance of a narrow navigation system

Cognition, Technology & Work - Due to the argued benefits of passenger comfort, cost savings, and road safety, the bus sector is showing increasing interest in advanced driver-assistance...     

Emissions of soot,PAHs, ultrafine particles,NOx, and other health relevant compounds from stressed burning of candles in indoor air

Burning candles release a variety of pollutants to indoor air, some of which are of concern for human health. We studied emissions of particles and gases from the stressed burning of five types of pillar candles with different wax and wick compositions. The stressed burning was introduced by controlled fluctuating air velocities in a 21.6 m³ laboratory chamber. The aerosol physicochemical properties were measured both in well-mixed chamber air and directly above the candle flame with online and offline techniques. All candles showed different emission profiles over time with high repeatability among replicates. The particle mass emissions from stressed burning for all candle types were dominated by soot (black carbon; BC). The wax and wick composition strongly influenced emissions of BC, PM_2.5, and particle-phase polycyclic aromatic hydrocarbons (PAHs), and to lower degree ultrafine particles, inorganic and organic carbon fraction of PM, but did not influence NO_x, formaldehyde, and gas-phase PAHs. Measurements directly above the flame showed empirical evidence of short-lived strong emission peaks of soot particles. The results show the importance of including the entire burn time of candles in exposure assessments, as their emissions can vary strongly over time. Preventing stressed burning of candles can reduce exposure to pollutants in indoor air.     

Supporting group collaboration with interpersonal awareness devices

An Interpersonal Awareness Device, or IPAD, is a hand-held or wearable device designed to support awareness and collaboration between people who are in the physical vicinity of each other. An IPAD is designed to supply constant awareness information to users in any location without relying on an underlying infrastructure. We have constructed one such device, the Hummingbird, which gives members of a group continuous aural and visual indications when other group members are close. We have used the Hummingbirds in several different situations to explore how they affect group awareness. These experiences indicated that the Hummingbird increased awareness between group members, and that it could complement other forms of communication, such as phone and email. In particular, we found the Hummingbird to be useful when a group of people were in an unfamiliar location, for instance during a trip, where no other communication support was available. We argue that IPADs such as the Hummingbird may fulfil important functions in modern work situations.