Reinier J. Jansen

XPS of nitrogen-containing functional groups on activated carbon

XPS is used to study the binding energy of the Cls, Nls and Ols photoelectrons of surface groups on several nitrogen-containing activated carbons. Specific binding energies are assigned to amide (399.9 eV). lactam and imidc (399.7 eV). pyridine (398.7 eV), pyrrole (400.7 eV), alkylamine. secondary amide and N-alkylimide (399.9 eV) and trialkylaminc (399.7 cV) functional groups on activated carbon. Supporting evidence is obtained for our hypothesis that the modification method governs the type of nitrogen function formed: ammoxidation leading to amides, animation to lactams and imides and further heat treatment to pyridine and pyrrole groups. Moreover, the XPS results confirm the attachment of tertiary amine groups to the carbon surface by reaction of pre-oxidized carbons with organic amines through ester and secondary amide or N-alkylimide spacing groups.

New acid catalyst comprising heteropoly acid on a mesoporous molecular sieve MCM-41

New solid acid catalysts, consisting of heteropoly acid (HPA) H3PW12O40 (PW) supported on a mesoporous pure-silica molecular sieve MCM-41, have been prepared and characterized by nitrogen physisorption, X-ray diffraction, FT-IR, and31P magic angle spinning NMR. The PW/MCM-41 compositions with PW loadings from 10 to 50 wt% have ∼ 30 Å uniformly-sized mesopores. HPA retains the Keggin structure on the MCM-41 surface and forms finely dispersed HPA species. No HPA crystal phase is developed even at HPA loadings as high as 50 wt%. PW/MCM-41 exhibits higher catalytic activity than H2SO4 or bulk PW in liquid-phase alkylation of 4-t-butylphenol (TBP) by isobutene and styrene. In the alkylation of TBP by styrene, PW/MCM-41 shows a size selectivity compared to bulk PW and PW/SiO2, providing higher yields of a 2-(1-phenylethyl)-4-t-butylphenol, at the expense of the more bulky 2,6-bis-(1-phenylethyl)-4-t-butylphenol. The PW/MCM-41 compositions, having strong acid sites and a regular mesoporous system, are promising catalysts for the acid-type conversion and formation of organic compounds of large molecular size.

17O NMR determination of proton sites in solid heteropoly acid H3PW12O40.31P,29Si and17O NMR, FT-IR and XRD study of H3PW12O40 and H4SiW12O40 supported on carbon

Abstract17O MAS NMR spectra for solid heteropoly acid (HPA) H3PW12O40 are reported. Comparison of solid-state and solution17O resonances shows that in the solid dehydrated H3PW12O40 terminal W=O oxygen atoms are the predominant protonation sites. H3PW12O40 and H4SiW12O40 supported on chemically activated carbon have been studied by means of NMR, FT-IR and XRD. The carbon-supported HPAs retain their Keggin structure and form finely dispersed HPA species. No HPA crystal phase is developed even at an HPA loading as high as 45 wt%.31P,29Si and17O MAS NMR spectra for bulk and carbon-supported HPAs indicate interaction of the HPA Keggin units with the carbon surface, causing large line broadening in the NMR spectra.

Heteropoly anion on carbon: characterization and use in 2,3,6-trimethylphenol oxidation

Heteropoly anion on modified carbon (PMo 9 V 3 O 40 6- ) is an effective catalyst for the oxidation of 2,3,6-trimethylphenol with molecular oxygen in AcOH/H 2 O 95/5 vol%. The selectivity and activity of this catalyst relates to the carbons surface modification. Heteropoly anions (HPAs) are strongly adsorbed to N-containing carbons. HPA adsorption can occur by coulombic attraction to protonated N-containing functional groups. HPAs retain the Keggin structure upon adsorption according to FTIR data. The solvent and the carbon surface chemistry determine the leaching of HPA, which is almost zero for N-containing carbon-supported HPA in acidic media.

Product Sound Design: Intentional and Consequential Sounds

In our daily life we are immersed in sounds that are generated by products. If one were to ask someone to name sounds produced by products, often sounds are mentioned that alarm or inform us (e.g., microwave oven beeps, telephone rings etc.). These are the sounds of which we are consciously aware. However, many sounds subconsciously play an important role in our interaction with a product. One hears if the battery of a toothbrush runs out of power; one hears the power of a vacuum cleaner and one hears if the bag is full; etc. Although these are all functional aspects, sound also plays a role in our aesthetic, quality, and emotional experi‐ ence of products. For example, one hears if the sound of a car door evokes a sense of quality. Car manufacturers have acoustical engineers to make sure that a slammed door will evoke this sense of quality. Sound quality and its relation to perception have been studied to some extent (e.g., Blauert & Jekosch, 1997; Bodden, 2000; Lyon, 2003). Often, these methodologies cover only one aspect of the design or evaluative process. Here we present a systematic approach to the inclusion of sound in the design process and its use as an essential aspect of controlling the quality of design and as a means of educating designers (and students) about the constit‐ uent parts of a product.

Task Prioritization in Dual-Tasking: Instructions versus Preferences.

The role of task prioritization in performance tradeoffs during multi-tasking has received widespread attention. However, little is known on whether people have preferences regarding tasks, and if so, whether these preferences conflict with priority instructions. Three experiments were conducted with a high-speed driving game and an auditory memory task. In Experiment 1, participants did not receive priority instructions. Participants performed different sequences of single-task and dual-task conditions. Task performance was evaluated according to participants’ retrospective accounts on preferences. These preferences were reformulated as priority instructions in Experiments 2 and 3. The results showed that people differ in their preferences regarding task prioritization in an experimental setting, which can be overruled by priority instructions, but only after increased dual-task exposure. Additional measures of mental effort showed that performance tradeoffs had an impact on mental effort. The interpretation of these findings was used to explore an extension of Threaded Cognition Theory with Hockey’s Compensatory Control Model.

Hysteresis in Mental Workload and Task Performance The Influence of Demand Transitions and Task Prioritization

Objective: We examine how transitions in task demand are manifested in mental workload and performance in a dual-task setting. Background: Hysteresis has been defined as the ongoing influence of demand levels prior to a demand transition. Authors of previous studies predominantly examined hysteretic effects in terms of performance. However, little is known about the temporal development of hysteresis in mental workload. Method: A simulated driving task was combined with an auditory memory task. Participants were instructed to prioritize driving or to prioritize both tasks equally. Three experimental conditions with low, high, and low task demands were constructed by manipulating the frequency of lane changing. Multiple measures of subjective mental workload were taken during experimental conditions. Results: Contrary to our prediction, no hysteretic effects were found after the high- to low-demand transition. However, a hysteretic effect in mental workload was found within the high-demand condition, which degraded toward the end of the high condition. Priority instructions were not reflected in performance. Conclusion: Online assessment of both performance and mental workload demonstrates the transient nature of hysteretic effects. An explanation for the observed hysteretic effect in mental workload is offered in terms of effort regulation. Application: An informed arrival at the scene is important in safety operations, but peaks in mental workload should be avoided to prevent buildup of fatigue. Therefore, communication technologies should incorporate the historical profile of task demand.

Designing and Deploying Meaningful Auditory Alarms for Control Systems

In the old days, spacecraft alarming notifications to operators were directed, upon arrival to ground, to one of those needle printers. Trained operators could tell, from the length and rhythm of the printer noise, what kind of alarm it was and therefore infer the criticality or the subject. Today, in monitoring and control systems (MCS) currently in use at the European Space Agency (ESA), there is no care to convey information in the sounds, and these alarm sounds have not been systematically designed to indicate the type of system failure and further elicit the desired and accurate operator response. Operators depend heavily on the graphical interfaces in order to pinpoint the source of alarm sounds (see Fig. 1) which further creates cognitive load. Similarly, switching cost from auditory perception to visual perception while finding the source of the information is undesirable when time can be a precious commodity for operators when monitoring valuable spacecraft. Therefore, ESA teamed up with Delft University of Technology and Plymouth University in order to investigate and design a new auditory display for the control rooms located in the European Space Operations Centre (ESOC), in Darmstadt, Germany

Sound meets image: freedom of expression in texture description

The use of sound was explored as means for expressing perceptual attributes of visual textures. Two sets of 17 visual textures were prepared: one set taken from the CUReT database, and one set synthesized to replicate the former set. Participants were instructed to match a sound texture with a visual texture displayed onscreen. A modified version of a Product Sound Sketching Tool was provided, in which an interactive physical interface was coupled to a frequency modulation synthesizer. Rather than selecting from a pre-defined set of sound samples, continuous exploration of the auditory space allowed for an increased freedom of expression. While doing so, participants were asked to describe what auditory and visual qualities they were paying attention to. It was found that participants were able to create sounds that matched visual textures. Based on differences in diversity of descriptions, synthetic textures were found to have less salient perceptual attributes than their original counterparts. Finally, three interesting sound synthesis clusters were found, corresponding with mutually exclusive description vocabularies.