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Report on the 2016 CoSPA and Traffic Flow Impact Operational Demonstration(4.64 MB)

Published in:
Project Report ATC-433, MIT Lincoln Laboratory

Summary

The 2016 Storm Prediction for Aviation (CoSPA) Demonstration was conducted from 1 June to 31 October 2016. As part of the demonstration, Federal Aviation Administration (FAA) facilities and commercial airlines were visited by MIT Lincoln Laboratory (MIT LL) observers, including initial training visits. Targeted field observations were conducted to gather information on how the CoSPA weather forecast was used in operations, to obtain feedback on new capabilities, and to collect comments for improvement.
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Summary

The 2016 Storm Prediction for Aviation (CoSPA) Demonstration was conducted from 1 June to 31 October 2016. As part of the demonstration, Federal Aviation Administration (FAA) facilities and commercial airlines were visited by MIT Lincoln Laboratory (MIT LL) observers, including initial training visits. Targeted field observations were conducted to gather...
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Germanium CCDs for large-format SWIR and x-ray imaging

Summary

Germanium exhibits high sensitivity to short-wave infrared (SWIR) and X-ray radiation, making it an interesting candidate for imaging applications in these bands. Recent advances in germanium processing allow for high-quality charge-coupled devices (CCDs) to be realized in this material. In this article, we discuss our evaluation of germanium as an absorber material for CCDs via fabrication and analysis of discrete devices such as diodes, metal-insulator-semiconductor capacitors, and buried-channel metal-oxide-semiconductor field-effect transistors (MOSFETs). We then describe fabrication of our first imaging device on germanium, a 32 x 1 x 8.1 um linear shift register. Based on this work, we find that germanium is a promising material for CCDs imaging in the SWIR and X-ray bands.
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Summary

Germanium exhibits high sensitivity to short-wave infrared (SWIR) and X-ray radiation, making it an interesting candidate for imaging applications in these bands. Recent advances in germanium processing allow for high-quality charge-coupled devices (CCDs) to be realized in this material. In this article, we discuss our evaluation of germanium as an...
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Raman Detection of a Single Airborne Aerosol Particles of Isovanillin(3.09 MB)

Summary

Raman spectroscopy of trapped single aerosol particles has been reported previously. However, detection of single aerosol particles via Raman spectroscopy in a flowing system has not been yet reported. In this paper, we describe the first detection of single 3 um flowing airborne aerosol particles flowing through a Raman system, which is a simplified version of the previously reported system with a 532-nm, 10W cw double-pass laser, 532-nm isolator, and double-sided collection optics. The current system has single-pass laser, no 532-nm isolator, and single-sided collection optics. Previous Raman detection of single aerosol particles has been made using trapped particles.
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Summary

Raman spectroscopy of trapped single aerosol particles has been reported previously. However, detection of single aerosol particles via Raman spectroscopy in a flowing system has not been yet reported. In this paper, we describe the first detection of single 3 um flowing airborne aerosol particles flowing through a Raman system,...
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Strong effect of azodye layer thickness on RM-stabilized photoalignment

Published in:
SID Symp. Digest of Tech. Papers, Vol. 48, No. 1, May 2017, pp. 578-81.

Summary

We have previously proposed a process for stabilizing azodye photo-alignment layers using a surface localized reactive mesogen (RM) layer applied by dissolving the monomer in a liquid crystal prior to filling the cell. Surprisingly, thin azodye layers (~3 nm) exhibit improved stability upon exposure to polarized light compared to thicker layers (~40 nm).
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Summary

We have previously proposed a process for stabilizing azodye photo-alignment layers using a surface localized reactive mesogen (RM) layer applied by dissolving the monomer in a liquid crystal prior to filling the cell. Surprisingly, thin azodye layers (~3 nm) exhibit improved stability upon exposure to polarized light compared to thicker...
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Broadband transparent optical phase change materials

Summary

We report a new group of optical phase change materials Ge-Sb-Se-Te (GSST) with low loss from telecom bands to LWIR. We further demonstrated GSST-integratedSiN photonics with significantly improved switching performance over conventional GST alloys.
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Summary

We report a new group of optical phase change materials Ge-Sb-Se-Te (GSST) with low loss from telecom bands to LWIR. We further demonstrated GSST-integratedSiN photonics with significantly improved switching performance over conventional GST alloys.
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Seismic barrier protection of critical infrastructure

Published in:
16th Annual IEEE Int. Symp. on Technologies for Homeland Security, HST 2017, 25-26 April 2017.

Summary

Each year, on average a major magnitude-8 earthquake strikes somewhere in the world. In addition, 10,000 earthquake related deaths occur annually, where collapsing buildings claim by far most lives. Moreover, in recent events, industry activity of oil extraction and wastewater reinjection are suspected to cause earthquake swarms that threaten high-value oil pipeline networks, U.S. oil storage reserves, and civilian homes. Earthquake engineering of building structural designs and materials have evolved over many years to minimize the destructive effects of seismic surface waves. However, even under the best engineering practices, significant damage and numbers of fatalities can still occur. In this paper, we present a novel concept and approach to redirect and attenuate the ground motion amplitudes caused by earthquakes by implementing an engineered subsurface seismic barrier – creating a form of metamaterial. The barrier is comprised of borehole array complexes and trench designs that impede and divert destructive seismic surface waves from a designated 'protection zone'. The barrier is also designed to divert not only surface waves in the aerial plane, but includes vertical 'V' shaped muffler structures composed of opposing boreholes to mitigate seismic waves from diffracting and traveling in the vertical plane. Computational 2D and 3D seismic wave propagation models developed at MIT Lincoln Laboratory suggest that borehole array and trench arrangements are critical to the redirection and self-interference reduction of broadband hazardous seismic waves in the vicinity of the structure to protect. The computational models are compared with experimental data obtained from large bench-scale physical models that contain scaled borehole arrays and trenches. These experiments are carried out at high frequencies, but with suitable material parameters and borehole dimensions. They indicate that effects of a devastating 7.0 Mw -magnitude earthquake can be reduced to those of a minor magnitude-4.5 or -5.5 Mw earthquake within a suitable protection zone. These results are very promising, and warrant validation in field scale tests.
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Summary

Each year, on average a major magnitude-8 earthquake strikes somewhere in the world. In addition, 10,000 earthquake related deaths occur annually, where collapsing buildings claim by far most lives. Moreover, in recent events, industry activity of oil extraction and wastewater reinjection are suspected to cause earthquake swarms that threaten high-value...
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Effect of surface roughness and H-termination chemistry on diamond's semiconducting surface conductance

Summary

The H-terminated surface of diamond when activated with NO2 produces a surface conduction layer that has been used to make FETs. Variations in processing can significantly affect this conduction layer. This article discusses the effect of diamond surface preparation and H termination procedures on surface conduction. Surface preparations that generate a rough surface result in a more conductive surface with the conductivity increasing with surface roughness. We hypothesize that the increase in conductance with roughness is the result of an increase of reactive sites that generate the carriers. Roughening the diamond surface is just one way to generate these sites and the rough surface is believed to be a separate property from the density of surface reactive sites. The presence of C in the H2 plasma used for H termination decreases surface conductance. A simple procedure for NO2 activation is demonstrated. Interpretation of electrical measurements and possible alternatives to activation with NO2 are discussed. Using Kasu's oxidation model for surface conductance as a guide, compounds other than NO2 have been found to activate the diamond surface as well.
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Summary

The H-terminated surface of diamond when activated with NO2 produces a surface conduction layer that has been used to make FETs. Variations in processing can significantly affect this conduction layer. This article discusses the effect of diamond surface preparation and H termination procedures on surface conduction. Surface preparations that generate...
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High-efficiency large-angle Pancharatnam phase deflector based on dual-twist design

Summary

We have previously shown through simulation that an optical beam deflector based on the Pancharatnam (geometric) phase can provide high efficiency with up to 80° deflection using a dual-twist structure for polarization-state control [Appl. Opt. 54, 10035 (2015)]. In this report, we demonstrate that its optical performance is as predicted and far beyond what could be expected for a conventional diffractive optical device. We provide details about construction and characterization of a ± 40° beam-steering device with 90% diffraction efficiency based on our dual-twist design at a 633nm wavelength.
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Summary

We have previously shown through simulation that an optical beam deflector based on the Pancharatnam (geometric) phase can provide high efficiency with up to 80° deflection using a dual-twist structure for polarization-state control [Appl. Opt. 54, 10035 (2015)]. In this report, we demonstrate that its optical performance is as predicted...
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Wind information requirements for NextGen applications phase 4 final report(5.87 MB)

Published in:
Project Report ATC-431, MIT Lincoln Laboratory

Summary

Many NextGen applications depend on access to high accuracy wind data due to time-based control elements, such as required time of arrival at a meter fix under 4D-Trajectory-Based Operations/Time of Arrival Control procedures or compliance to an assigned spacing goal between aircraft under Interval Management procedures. The work described in this report summarizes the activities conducted in FY15, which builds upon prior work.
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Summary

Many NextGen applications depend on access to high accuracy wind data due to time-based control elements, such as required time of arrival at a meter fix under 4D-Trajectory-Based Operations/Time of Arrival Control procedures or compliance to an assigned spacing goal between aircraft under Interval Management procedures. The work described in...
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Characterization of nitrated sugar alcohols by atmospheric-pressure chemical-ionization mass spectrometry

Published in:
Rapid Commun. Mass Spectrom., Vol. 33, 2017, pp. 333-43.

Summary

RATIONALE: The nitrated sugar alcohols mannitol hexanitrate (MHN), sorbitol hexanitrate (SHN) and xylitol pentanitrate (XPN) are in the same class of compounds as the powerful military-grade explosive pentaerythritol tetranitrate (PETN) and the homemade explosive erythritol tetranitrate (ETN) but, unlike for PETN and ETN, ways to detect MHN, SHN and XPN by mass spectrometry (MS) have not been fully investigated. METHODS: Atmospheric-pressure chemical-ionization mass spectrometry (APCI-MS) was used to detect ions characteristic of nitrated sugar alcohols. APCI time-of-flight mass spectrometry (APCI-TOF MS) and collision-induced dissociation tandem mass spectrometry (CID MS/MS) were used for confirmation of each ion assignment. In addition, the use of the chemical ionization reagent dichloromethane was investigated to improve sensitivity and selectivity for detection of MHN, SHN and XPN. RESULTS: All the nitrated sugar alcohols studied followed similar fragmentation pathways in the APCI source. MHN, SHN and XPN were detectable as fragment ions formed by the loss of NO2, HNO2, NO3, and CH2NO2 groups, and in the presence of dichloromethane chlorinated adduct ions were observed. It was determined that in MS/MS mode, chlorinated adducts of MHN and SHN had the lowest limits of detection (LODs), while for XPN the lowest LOD was for the [XPN-NO2]- fragment ion. Partially nitrated analogs of each of the three compounds were also present in the starting materials, and ions attributable to these compounds versus those formed from in-source fragmentation of MHN, SHN, and XPN were distinguished and assigned using liquid chromatography APCI-MS and ESI-MS. CONCLUSIONS: The APCI-MS technique provides a selective and sensitive method for the detection of nitrated sugar alcohols. The methods disclosed here will benefit the area of explosives trace detection for counterterrorism and forensics.
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Summary

RATIONALE: The nitrated sugar alcohols mannitol hexanitrate (MHN), sorbitol hexanitrate (SHN) and xylitol pentanitrate (XPN) are in the same class of compounds as the powerful military-grade explosive pentaerythritol tetranitrate (PETN) and the homemade explosive erythritol tetranitrate (ETN) but, unlike for PETN and ETN, ways to detect MHN, SHN and XPN...
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