1,423 research outputs found
Modifications to an Existing Glycol Retention Pond and Alternative Technologies Review for Aircraft Deicing Operations and Glycol Recovery and Treatment: Dane County Regional Airport
The purpose of this study was to review new aircraft deicing technologies and developments and surmise which approach may be the most appropriate for the Dane County Regional Airport’s (KMSN) expansion plans, size, available funds, and environmental impact reduction efforts. This paper focuses on the emerging glycol source reduction issues that may be most suitable for this particular airport. A new deicing technology at KMSN would reduce the amount of aircraft deicing fluid used, allow for effacing flight operations, limit environmental impact, and lessen the costs of maintaining and operating the current glycol fluid recovery and treatment system.
Storm water discharge regulations are becoming increasingly stringent at airports in the United States. The FAA requires aircraft deicing when weather conditions warrant. The EPA requires that glycol fluid be collected and treated prior to proper disposal. Passenger safety is the foremost concern for airports and airlines and is the cornerstone by which all aircraft deicing decisions are made. The advent of new more environmentally-friendly aircraft deicing technologies is facilitating the balance between aviation safety and environmental protection
Suspected Unapproved Parts in the Aviation Industry: Consideration of System Safety and Control
It is well known and highly touted that there is a historically high level of safety in U.S. air transportation. The American traveling public has come to expect this level of safety in the skies. Key elements in maintaining this high level of air safety are specific federal regulations, along with Federal Aviation Administration (FAA) surveillance, inspection, and enforcement activities. The U.S. Code of Federal Regulations include a framework of rules governing the design, manufacture, and use of aviation products and parts. The rules are in place to assist the aviation industry in maintaining its excellent safety record, and serve as a means to prevent unwanted or suspected deficient parts from being used on aircraft
Resolving Phonon Fock States in a Multimode Cavity with a Double-Slit Qubit
We resolve phonon number states in the spectrum of a superconducting qubit
coupled to a multimode acoustic cavity. Crucial to this resolution is the sharp
frequency dependence in the qubit-phonon interaction engineered by coupling the
qubit to surface acoustic waves in two locations separated by acoustic
wavelengths. In analogy to double-slit diffraction, the resulting
self-interference generates high-contrast frequency structure in the
qubit-phonon interaction. We observe this frequency structure both in the
coupling rate to multiple cavity modes and in the qubit spontaneous emission
rate into unconfined modes. We use this sharp frequency structure to resolve
single phonons by tuning the qubit to a frequency of destructive interference
where all acoustic interactions are dispersive. By exciting several detuned yet
strongly-coupled phononic modes and measuring the resulting qubit spectrum, we
observe that, for two modes, the device enters the strong dispersive regime
where single phonons are spectrally resolved.Comment: 9 pages, 8 figures; revised arguments in paragraphs 3 and 8, added
Hamiltonian description, and corrected typo
Reflector antennas with low sidelobes, low cross polarization, and high aperture efficiency
Techniques are presented for computing the horn near field patterns on the subreflectors and for correcting the phase center errors of the horn pattern by shaping the subreflector surface. The diffraction pattern computations for scanned beams are described. The effects of dish aperture diffraction on pattern bandwidth are investigated. A model antenna consisting of a reflector, shaped subreflector, and corrugated feed horn is described
Towards a systematic understanding of the influence of temperature on glycosylation reactions
Glycosidic bond formation is a continual challenge for practitioners. Aiming to enhance the reproducibility and efficiency of oligosaccharide synthesis, we studied the relationship between glycosyl donor activation and reaction temperature. A novel semi-automated assay revealed diverse responses of members of a panel of thioglycosides to activation at various temperatures. The patterns of protecting groups and the thiol aglycon combine to cause remarkable differences in temperature sensitivity among glycosylating agents. We introduce the concept of donor activation temperature to capture experimental insights, reasoning that glycosylations performed below this reference temperature evade deleterious side reactions. Activation temperatures enable a simplified temperature treatment and facilitate optimization of glycosylating agent (building block) usage. Isothermal glycosylation below the activation temperature halved the equivalents of building block required in comparison to the standard ‘ramp’ regime used in solution- and solid-phase oligosaccharide synthesis to-date
On resin synthesis of sulfated oligosaccharides
Sulfated glycans are involved in many biological processes, making well-defined sulfated oligosaccharides highly sought molecular probes. These compounds are a considerable synthetic challenge, with each oligosaccharide target requiring specific synthetic protocols and extensive purifications steps. Here, we describe a general on resin approach that simplifies the synthesis of sulfated glycans. The oligosaccharide backbone, obtained by Automated Glycan Assembly (AGA), is subjected to regioselective sulfation and hydrolysis of protecting groups. The protocol is compatible with several monosaccharides and allows for multi-sulfation of linear and branched glycans. Seven diverse, biologically relevant sulfated glycans were prepared in good to excellent overall yield
Nonadiabatic derivative couplings through multiple Franck-Condon modes dictate the energy gap law for near and short-wave infrared dye molecules
Near infrared (NIR, 700 - 1,000 nm) and short-wave infrared (SWIR, 1,000 -
2,000 nm) dye molecules exhibit significant nonradiative decay rates from the
first singlet excited state to the ground state. While these trends can be
empirically explained by a simple energy gap law, detailed mechanisms of the
nearly universal behavior have remained unsettled for many cases. Theoretical
and experimental results for two representative NIR/SWIR dye molecules reported
here clarify an important mechanism of such nature. It is shown that the first
derivative nonadiabatic coupling terms serve as major coupling pathways for
nonadiabatic decay processes exhibiting the energy gap law behavior and that
vibrational modes other than the highest frequency ones also make significant
contributions to the rate. This assessment is corroborated by further
theoretical comparison with possible alternative mechanisms of intersystem
crossing to triplet states and also by comparison with experimental data for
deuterated molecules
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