Experimental and Kinetic modeling of soot formation in counterflow flames of surrogate fuel components: n-dodecane and iso-dodecane
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Photodissociation of the i-C 3 H 7 O radical is investigated using fast beam photofragment translational spectroscopy. Neutral i-C 3 H 7 O radicals are produced through the photodetachment of a fast beam of i-C 3 H 7 O - anions and are subsequently dissociated at 248 nm (5.0 eV). Furthermore, the dominant product channels are CH 3 + CH 3 CHO and OH + C 3 H 6 with some contribution from H + C 3 H 6 O. The CH 3 and H loss channels are attributed to dissociation on the ground electronic state of i-C 3 H 7 O, but in a nonstatistical manner because calculated RRKM dissociation rates exceed the rate of energy randomization. Translational energy and angular distributions for OH loss are consistent with ground state dissociation, but the branching ratio for this channel is considerably higher than predicted from RRKM rate calculations. Additionally, i-C 3 H 7 O undergoes three-body fragmentation to CH 3 + CH 3 + HCO and CH 3 + CH 4 + CO. These three-body channels are attributed to dissociation of i-C 3 H 7 O to CH 3 + CH 3 CHO, followed by secondary dissociation of CH 3 CHO on its ground electronic state.
Despite remarkable progress toward the understanding of the formation pathways leading to polycyclic aromatic hydrocarbons (PAHs) in combustion systems and in deep space, the complex reaction pathways leading to nitrogen-substituted PAHs (NPAHs) at low temperatures of molecular clouds and hydrocarbon-rich, nitrogen-containing atmospheres of planets and their moons like Titan have remained largely obscure. Here, we demonstrate through laboratory experiments and computations that the simplest prototype of NPAHs – quinoline and isoquinoline (C 9 H 7 N) – can be synthesized via rapid and de-facto barrier-less reactions involving o-, m- and p-pyridinyl radicals (C 5 H 4 N˙) with vinylacetylene (C 4 H 4 ) under low-temperature conditions.
Reaction of a terphenyl bis(anilide) ligand with trivalent halide precursors of Ce and early actinides yield both neutral and “-ate” complexes. These molecules afford comparative insight into f-block metal–arene bonding.
A generation-to-load simulation estimated the impact, in terms of production costs and CO2 emissions, attributable to the joint optimization of electric power generation and flexible end uses to support increasing penetrations of renewable energy. Newly conceived, evaluated, and foundational in developing a U.S. National Standard was a transaction-less yet continuous demand response system based on a day-ahead optimum load shape (OLS) designed to encourage Internet-connected devices to autonomously and voluntarily explore options to favour lowest cost generators - without requiring two-way communications, personally identifiable information, or customer opt-in. Boundary conditions used for model calibration included historical weather, residential building stock construction attributes, home appliance and device empirical operating schedules, prototypical power distribution feeder models, thermal generator heat rates, startup and ramping constraints, and fuel costs. Results of an hourly-based annual case study of Texas indicate a 1/3 reduction in production costs and a 1/5 reduction in CO2 emissions are possible.
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Cargo inspection systems exploit the broad bremsstrahlung spectrum from a 6-10 MeV, low-duty cycle electron accelerator which in the presence of significant backgrounds presents challenges in image and material identification. An alternative approach is to use ions which can excite nuclear states either directly, or through generation of secondary high-energy signature gammas produced from nuclear interactions in a target. RadiaBeam is designing a compact sector isocyclotron 1.25 m in radius, with high-gradient cavities to accelerate multi-ion species up to 15-20 MeV/u with large turn-to turn, centimeter-level separation for low-loss extraction without lossy foil stripping. A strong-focusing radial field profile will be optimized in a separated-sector format for control over machine tune simultaneous with isochronous orbist requirements for high-current (~0.5 milliamp) operation. Innovation in injection will be introduced to replace the high-loss central region. Non-security applications of the cyclotron include medical isotope production, ion radiobiology, as well as material science research and ion instrumentation development.
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