1,915 research outputs found
Carbon capture in the cement industry: technologies, progress, and retrofitting
Several different carbon-capture technologies have been proposed for use in the cement industry. This paper reviews their attributes, the progress that has been made toward their commercialization, and the major challenges facing their retrofitting to existing cement plants. A technology readiness level (TRL) scale for carbon capture in the cement industry is developed. For application at cement plants, partial oxy-fuel combustion, amine scrubbing, and calcium looping are the most developed (TRL 6 being the pilot system demonstrated in relevant environment), followed by direct capture (TRL 4–5 being the component and system validation at lab-scale in a relevant environment) and full oxy-fuel combustion (TRL 4 being the component and system validation at lab-scale in a lab environment). Our review suggests that advancing to TRL 7 (demonstration in plant environment) seems to be a challenge for the industry, representing a major step up from TRL 6. The important attributes that a cement plant must have to be “carbon-capture ready” for each capture technology selection is evaluated. Common requirements are space around the preheater and precalciner section, access to CO2 transport infrastructure, and a retrofittable preheater tower. Evidence from the electricity generation sector suggests that carbon capture readiness is not always cost-effective. The similar durations of cement-plant renovation and capture-plant construction suggests that synchronizing these two actions may save considerable time and money
Phase diagram of Janus Particles
We deeply investigate a simple model representative of the recently
synthesized Janus particles, i.e. colloidal spherical particles whose surface
is divided into two areas of different chemical composition. When the two
surfaces are solvophilic and solvophobic, these particles constitute the
simplest example of surfactants. The phase diagram includes a colloidal-poor
(gas) colloidal-rich (liquid) de-mixing region, which is progressively
suppressed by the insurgence of micelles, providing the first model where
micellization and phase-separation are simultaneously observed. The coexistence
curve is found to be negatively sloped in the temperature-pressure plane,
suggesting that Janus particles can provide a colloidal system with anomalous
thermodynamic behavior.Comment: 5 pages, 5 figures, Phys. Rev. Lett. in pres
Does Roush show that evidence should be probable?
This paper critically analyzes Sherrilyn Roush’s (Tracking truth: knowledge, evidence and science, 2005) definition of evidence and especially her powerful defence that in the ideal, a claim should be probable to be evidence for anything. We suggest that Roush treats not one sense of ‘evidence’ but three: relevance, leveraging and grounds for knowledge; and that different parts of her argument fare differently with respect to different senses. For relevance, we argue that probable evidence is sufficient but not necessary for Roush’s own two criteria of evidence to be met. With respect to grounds for knowledge, we agree that high probability evidence is indeed ideal for the central reason Roush gives: When believing a hypothesis on the basis of e it is desirable that e be probable. But we maintain that her further argument that Bayesians need probable evidence to warrant the method they recommend for belief revision rests on a mistaken interpretation of Bayesian conditionalization. Moreover, we argue that attempts to reconcile Roush’s arguments with Bayesianism fail. For leveraging, which we agree is a matter of great importance, the requirement that evidence be probable suffices for leveraging to the probability of the hypothesis if either one of Roush’s two criteria for evidence are met. Insisting on both then seems excessive. To finish, we show how evidence, as Roush defines it, can fail to track the hypothesis. This can remedied by adding a requirement that evidence be probable, suggesting another rationale for taking probable evidence as ideal—but only for a grounds-for-knowledge sense of evidence
Change in the magnetic structure of (Bi,Sm)FeO3 thin films at the morphotropic phase boundary probed by neutron diffraction
We report on the evolution of the magnetic structure of BiFeO3 thin films
grown on SrTiO3 substrates as a function of Sm doping. We determined the
magnetic structure using neutron diffraction. We found that as Sm increases,
the magnetic structure evolves from a cycloid to a G-type antiferromagnet at
the morphotropic phase boundary, where there is a large piezoelectric response
due to an electric-field induced structural transition. The occurrence of the
magnetic structural transition at the morphotropic phase boundary offers
another route towards room temperature multiferroic devices
Interplay of local hydrogen-bonding and long-ranged dipolar forces in simulations of confined water
Spherical truncations of Coulomb interactions in standard models for water
permit efficient molecular simulations and can give remarkably accurate results
for the structure of the uniform liquid. However truncations are known to
produce significant errors in nonuniform systems, particularly for
electrostatic properties. Local molecular field (LMF) theory corrects such
truncations by use of an effective or restructured electrostatic potential that
accounts for effects of the remaining long-ranged interactions through a
density-weighted mean field average and satisfies a modified Poisson's equation
defined with a Gaussian-smoothed charge density. We apply LMF theory to three
simple molecular systems that exhibit different aspects of the failure of a
naive application of spherical truncations -- water confined between
hydrophobic walls, water confined between atomically-corrugated hydrophilic
walls, and water confined between hydrophobic walls with an applied electric
field. Spherical truncations of 1/r fail spectacularly for the final system in
particular, and LMF theory corrects the failings for all three. Further, LMF
theory provides a more intuitive way to understand the balance between local
hydrogen bonding and longer-ranged electrostatics in molecular simulations
involving water.Comment: Submitted to PNA
Quantifying the radiation belt seed population in the 17 March 2013 electron acceleration event
Abstract We present phase space density (PSD) observations using data from the Magnetic Electron Ion Spectrometer instrument on the Van Allen Probes for the 17 March 2013 electron acceleration event. We confirm previous results and quantify how PSD gradients depend on the first adiabatic invariant. We find a systematic difference between the lower-energy electrons (1-MeV with a source region within the radiation belts. Our observations show that the source process begins with enhancements to the 10s-100s-keV energy seed population, followed by enhancements to the \u3e1-MeV population and eventually leading to enhancements in the multi-MeV electron population these observations provide the clearest evidence to date of the timing and nature of the radial transport of a 100s keV electron seed population into the heart of the outer belt and subsequent local acceleration of those electrons to higher radiation belt energies. Key Points Quantification of phase space density gradients inside geostationary orbit Clear differences between the source of low energy and relativistic electrons Clear observations of how the acceleration process evolves in energy
Solubility of carbon dioxide in aqueous blends of 2-amino-2-methyl-1-propanol and piperazine
In this work, we report new solubility data for carbon dioxide in aqueous blends of 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ). A static-analytical apparatus, validated in previous work, was employed to obtain the results at temperatures of (313.2, 333.2, 373.2, 393.2) K, and at total pressures up to 460 kPa. Two different solvent blends were studied, both having a total amine mass fraction of 30%: (25 mass% AMP+5 mass% PZ) and (20 mass% AMP+10 mass% PZ). Comparisons between these PZ activated aqueous AMP systems and 30 mass% aqueous AMP have been made in terms of their cyclic capacities under typical scrubbing conditions of 313 K in the absorber and 393 K in the stripper. The Kent–Eisenberg model was used to correlate the experimental data
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