A Physics-based Investigation of Pt-salt Doped Carbon Nanotubes for Local Interconnects

We investigate, by combining physical and electrical measurements together with an atomistic-to-circuit modeling approach, the conductance of doped carbon nanotubes (CNTs) and their eligibility as possible candidate for next generation back-end-of-line (BEOL) interconnects. Ab-initio simulations predict a doping-related shift of the Fermi level, which reduces shell chirality variability and improves electrical conductance up to 90% by converting semiconducting shells to metallic. Circuit-level simulations predict up to 88% signal delay improvement with doped vs. pristine CNT. Electrical measurements of Pt-salt doped CNTs provide up to 50% of resistance reduction which is a milestone result for future CNT interconnect technology

Aerosol characteristics and particle production in the upper troposphere over the Amazon Basin

Airborne observations over the Amazon Basin showed high aerosol particle concentrations in the upper troposphere (UT) between 8 and 15 km altitude, with number densities (normalized to standard temperature and pressure) often exceeding those in the planetary boundary layer (PBL) by 1 or 2 orders of magnitude. The measurements were made during the German–Brazilian cooperative aircraft campaign ACRIDICON–CHUVA, where ACRIDICON stands for Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems and CHUVA is the acronym for Cloud Processes of the Main Precipitation Systems in Brazil: A Contribution to Cloud Resolving Modeling and to the GPM (global precipitation measurement), on the German High Altitude and Long Range Research Aircraft (HALO). The campaign took place in September–October 2014, with the objective of studying tropical deep convective clouds over the Amazon rainforest and their interactions with atmospheric trace gases, aerosol particles, and atmospheric radiation. Aerosol enhancements were observed consistently on all flights during which the UT was probed, using several aerosol metrics, including condensation nuclei (CN) and cloud condensation nuclei (CCN) number concentrations and chemical species mass concentrations. The UT particles differed sharply in their chemical composition and size distribution from those in the PBL, ruling out convective transport of combustion-derived particles from the boundary layer (BL) as a source. The air in the immediate outflow of deep convective clouds was depleted of aerosol particles, whereas strongly enhanced number concentrations of small particles ( 90 nm) particles in the UT, which consisted mostly of organic matter and nitrate and were very effective CCN. Our findings suggest a conceptual model, where production of new aerosol particles takes place in the continental UT from biogenic volatile organic material brought up by deep convection and converted to condensable species in the UT. Subsequently, downward mixing and transport of upper tropospheric aerosol can be a source of particles to the PBL, where they increase in size by the condensation of biogenic volatile organic compound (BVOC) oxidation products. This may be an important source of aerosol particles for the Amazonian PBL, where aerosol nucleation and new particle formation have not been observed. We propose that this may have been the dominant process supplying secondary aerosol particles in the pristine atmosphere, making clouds the dominant control of both removal and production of atmospheric particles

Concentration addition, independent action and generalized concentration addition models for mixture effect prediction of sex hormone synthesis in vitro

Humans are concomitantly exposed to numerous chemicals. An infinite number of combinations and doses thereof can be imagined. For toxicological risk assessment the mathematical prediction of mixture effects, using knowledge on single chemicals, is therefore desirable. We investigated pros and cons of the concentration addition (CA), independent action (IA) and generalized concentration addition (GCA) models. First we measured effects of single chemicals and mixtures thereof on steroid synthesis in H295R cells. Then single chemical data were applied to the models; predictions of mixture effects were calculated and compared to the experimental mixture data. Mixture 1 contained environmental chemicals adjusted in ratio according to human exposure levels. Mixture 2 was a potency adjusted mixture containing five pesticides. Prediction of testosterone effects coincided with the experimental Mixture 1 data. In contrast, antagonism was observed for effects of Mixture 2 on this hormone. The mixtures contained chemicals exerting only limited maximal effects. This hampered prediction by the CA and IA models, whereas the GCA model could be used to predict a full dose response curve. Regarding effects on progesterone and estradiol, some chemicals were having stimulatory effects whereas others had inhibitory effects. The three models were not applicable in this situation and no predictions could be performed. Finally, the expected contributions of single chemicals to the mixture effects were calculated. Prochloraz was the predominant but not sole driver of the mixtures, suggesting that one chemical alone was not responsible for the mixture effects. In conclusion, the GCA model seemed to be superior to the CA and IA models for the prediction of testosterone effects. A situation with chemicals exerting opposing effects, for which the models could not be applied, was identified. In addition, the data indicate that in non-potency adjusted mixtures the effects cannot always be accounted for by single chemicals

Deuren plaatsen met plezier : het gaat vlot met de glasrobot

Deze goede praktijk is een initiatief van TNO en Ministerie van Sociale Zaken en Werkgelegenheid

Musculoskeletal discomfort during VDU tasks; input for a smart office chair

TNO and BMA Ergonomics are developing a so-called smart office chair. This chair is supposed to provide feedback on postures and movements during seated office work. The feedback should enable the user (i.e. the worker doing VDU tasks) to perform his or her work with less discomfort and in a more productive way. One part of this project is a study about the development of musculoskeletal discomfort during VDU work, sitting in various postures. Nineteen subjects did 2 types of VDU work in a laboratory setting: call-centre and data-entry. They were instructed to work in a certain sitting posture for 30 minutes, without pauses. After that, they could relax for 30 minutes. Four sitting postures were imposed; the 5th one was each individual’s freely chosen working posture: the reference posture. Every 3 minutes, local perceived discomfort (LPD) of 5 body regions was determined, by letting subjects rate their LPD on a 10-point-scale. From that we calculated the relative LPD-dose, setting the dose of the ergonomic optimal posture to 100%. LPD-doses were not significantly different between the 2 VDU-tasks. Different sitting postures did lead to significantly different LPD-doses; the lowest in the ergonomic optimal posture and the highest one in the ‘vulture’ posture. From the individual development of LPD during 30 minutes of VDU work and a prior evaluation of the health risks of prolonged LPD, we can deduce the period of time a subject is allowed to work in a specific posture. These data can serve as input for a demonstration model of the smart office chair

Local density of states probed by single electron tunneling

Mesoscopic fluctuations of the local density of states (LDOS) in a highly degenerate semiconductor are studied by single electron tunneling through a discrete localized state. A damping of the amplitude of the LDOS fluctuations with increasing voltage is observed. We attribute this damping to inelastic processes in the emitter. From this inelastic broadening of our spectrometer the quasi-particle relaxation is evaluated