9,947 research outputs found
Defending Truths, Restoring Worlds
The post in post-truth is premature, and also assigns too much importance to Brexit and the victory of Donald Trump in the US. Worst of all, it can foster the impression that people like Brexit voters and Trump supporters are irredeemably exiled in alternative fact bubbles beyond the reach of science, rational thought, and common decency. We have to find ways to work productively with these kinds of citizens, instead of merely condemning them, if we want to trigger both a worldwide alternative energy revolution and the revolution in politics and economics that a truly just and sustainable energy transition demands
Culture Jamming: Activism and the Art of Cultural Resistance by Marilyn DeLaure and Moritz Fink
Review of Marilyn DeLaure and Moritz Fink\u27s Culture Jamming: Activism and the Art of Cultural Resistance
Hyperobjects: Philosophy and Ecology After the End of the World by Timothy Morton
Welling reviews Timothy Morton\u27s book Hyperobjects: Philosophy and Ecology after the End of the World (Minneapolis: U of Minnesota P, 2013)
Living Oil: Petroleum Culture in the American Century by Stephanie LeMenager
Bart H. Welling reviews Living Oil: Petroleum Culture in the American Cenutry by Stephanie LeMenager
ISFET based enzyme sensors
This paper reviews the results that have been reported on ISFET based enzyme sensors. The most important improvement that results from the application of ISFETs instead of glass membrane electrodes is in the method of fabrication. Problems with regard to the pH dependence of the response and the dynamic range as well as the influence of the sample buffer capacity have not been solved. As a possible solution we introduce a coulometric system that compensates for the analyte buffer capacity. If the pH in the immobilized enzyme layer is thus controlled, the resulting pH-static enzyme sensor has an output that is independent of the sample pH and buffer capacity and has an expanded linear range
Cooperative look-ahead control for fuel-efficient and safe heavy-duty vehicle platooning
The operation of groups of heavy-duty vehicles (HDVs) at a small
inter-vehicular distance (known as platoon) allows to lower the overall
aerodynamic drag and, therefore, to reduce fuel consumption and greenhouse gas
emissions. However, due to the large mass and limited engine power of HDVs,
slopes have a significant impact on the feasible and optimal speed profiles
that each vehicle can and should follow. Therefore maintaining a short
inter-vehicular distance as required by platooning without coordination between
vehicles can often result in inefficient or even unfeasible trajectories. In
this paper we propose a two-layer control architecture for HDV platooning aimed
to safely and fuel-efficiently coordinate the vehicles in the platoon. Here,
the layers are responsible for the inclusion of preview information on road
topography and the real-time control of the vehicles, respectively. Within this
architecture, dynamic programming is used to compute the fuel-optimal speed
profile for the entire platoon and a distributed model predictive control
framework is developed for the real-time control of the vehicles. The
effectiveness of the proposed controller is analyzed by means of simulations of
several realistic scenarios that suggest a possible fuel saving of up to 12%
for the follower vehicles compared to the use of standard platoon controllers.Comment: 16 pages, 16 figures, submitted to journa
The pH-static enzyme sensor : An ISFET-based enzyme sensor, insensitive to the buffer capacity of the sample
An ISFET-based urea sensor is combined with a noble-metal electrode which provides continuous coulometric titration of the products of the enzymatic reaction. The sensor thus becomes independent of the buffer capacity of the sample; and because the enzyme is operating at a constant pH, the linear response range is expanded
Evaluation of the sensor properties of the pH-static enzyme sensor
The pH-static enzyme sensor consists of a chemical sensor-actuator system covered with a thin enzyme-entrapping membrane. By the electrochemical generation of protons or hydroxyl ions, pH changes induced by the conversion of a substrate by the enzymatic reaction are compensated. The pH inside the membrane remains at a constant level and the control current is linearly related to the substrate concentration and independent of the buffer capacity of the sample. The sensitivity and linearity of the sensor response are evaluated. Depending on the enzyme load of the membrane, the operation of the sensor is either diffusion controlled or determined by the enzyme kinetics
The effect of the amido substituent on polymer molecular weight in propene homopolymerisation by titanium cyclopentadienyl-amide catalysts
In the homopolymerisation of propene by the cyclopentadienyl-amide titanium catalyst systems [η5,η1-C5H4(CH2)2NR]TiCl2/MAO and [η5,η1-C5H4(CH2)2NR]Ti(CH2Ph)2/B(C6F5)3 (R = tBu, iPr, Me), the catalyst with the smallest substituent (Me) on the amido moiety consistently gives the highest polymer molecular weight. This differs from the trend usually observed in related catalysts with tetramethylcyclopentadienyl-amide ancillary ligands, where larger amide substituents result in higher molecular weights. Based on the present information a hypothesis is formulated in which an increased cation-anion interaction for the less sterically hindered catalyst is responsible for disfavouring chain transfer relative to chain growth.
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