Report on FAA Deicing Program at La Guardia and O'Hare Airports

DOT National Transportation Integrated Search

1996-10-02

The Office of Inspector General, Department of Transportation; conducted a : followup inspection of the Federal Aviation Administration (FAA) Deicing : Program. We initiated this study to observe deicing operations as a followup to : our report on th...

Electrical deicing utilizing carbon fiber tape for asphalt approach and crosswalk phase I - literature review.

DOT National Transportation Integrated Search

2016-06-30

The purpose of this study is to provide a comprehensive literature review of electrical deicing technology for possible application in asphalt approach and crosswalks. A : thorough review of existing and emerging deicing technology for snow/ice melti...

Deicing chemicals as source of constituents of highway runoff

USGS Publications Warehouse

Granato, G.E.

1996-01-01

The dissolved major and trace constituents of deicing chemicals as a source of constituents in highway runoff must be quantified for interpretive studies of highway runoff and its effects on surface water and groundwater. Dissolved constituents of the deicing chemicals-sodium chloride, calcium chloride, and premix (a mixture of sodium and calcium chloride)-were determined by analysis of salt solutions created in the laboratory and are presented as mass ratios to chloride. Deicing chemical samples studied are about 98 and 97 percent pure sodium chloride and calcium chloride, respectively: however, each has a distinct major and trace ion constituent signature. The greatest impurity in sodium chloride road sail samples was sulfate, followed by calcium, potassium, bromide, vanadium, magnesium, fluoride, and other constituents with a ratio to chloride of less than 0.0001 by mass. The greatest impurity in the calcium chloride road salt samples was sodium, followed by potassium, sulfate, bromide, silica, fluoride. strontium, magnesium, and other constituents with a ratio to chloride of less than 0.0001 by mass. Major constituents of deicing chemicals in highway runoff may account for a substantial source of annual chemical loads. Comparison of estimated annual loads and first flush concentrations of deicing chemical constituents in highway runoff with those reported in the literature indicate that although deicing chemicals are not a primary source of trace constituents, they are not a trivial source, either. Therefore, deicing chemicals should be considered as a source of many major and trace constituents in highway and urban runoff.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lazauskas, A., E-mail: Algirdas.LAZAUSKAS@stud.ktu.lt; Guobienė, A., E-mail: Asta.GUOBIENE@ktu.lt; Prosyčevas, I., E-mail: IGORPROS@mail.ru

This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 ± 1°) SiO{sub 2} nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO{sub 2} nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, water droplets on SiO{sub 2} nanocomposite film surface are subjected to a series of icing and deicing cycles in a humid (∼ 70% relative humidity) atmosphere and the resulting morphological changes are monitored and characterized using atomic force microscopy (AFM) and contact angle measurements. Our data show that the formation of the frozen or thawed water droplet, with no furthermore » shape change, on superhydrophobic SiO{sub 2} nanocomposite film, is obtained faster within each cycle as the number of the icing/deicing cycles increases. After 10 icing and deicing cycles, the superhydrophobic SiO{sub 2} nanocomposite film had a water contact angle value of 146 ± 2° which is effectively non-superhydrophobic. AFM analysis showed that the superhydrophobic SiO{sub 2} nanocomposite film surface area under the water droplet undergoes gradual mechanical damage during the repetitive icing/deicing cycles. We propose a possible mechanism of the morphological changes to the film surface that take place during the consecutive icing/deicing experiments. - Highlights: • Superhydrophobic film is subjected to repetitive icing/deicing treatments. • Water droplet shape transition is recorded and characterized thereafter. • Atomic force microscopy and contact angle measurements are performed. • The surface undergoes gradual mechanical damage during repetitive icing/deicing. • Mechanism for the observed surface morphological changes is suggested.« less

14 CFR 23.1095 - Carburetor deicing fluid flow rate.

Code of Federal Regulations, 2010 CFR

2010-01-01

.... (b) The fluid must be introduced into the air induction system— (1) Close to, and upstream of, the carburetor; and (2) So that it is equally distributed over the entire cross section of the induction system... Induction System § 23.1095 Carburetor deicing fluid flow rate. (a) If a carburetor deicing fluid system is...

Passive Anti-Icing and Active Deicing Films.

PubMed

Wang, Tuo; Zheng, Yonghao; Raji, Abdul-Rahman O; Li, Yilun; Sikkema, William K A; Tour, James M

2016-06-08

Anti-icing and deicing are the two major pathways for suppressing adhesion of ice on surfaces, yet materials with dual capabilities are rare. In this work, we have designed a perfluorododecylated graphene nanoribbon (FDO-GNR) film that takes advantage of both the low polarizability of perfluorinated carbons and the intrinsic conductive nature of graphene nanoribbons. The FDO-GNR films are superhydrophobic with a sheet resistance below 8 kΩ·sq(-1) and then exhibit an anti-icing property that prevents freezing of incoming ice-cold water down to -14 °C. After that point, voltage can be applied to the films to resistively heat and deice the surface. Further a lubricating liquid can be employed to create a slippery surface to improve the film's deicing performance. The FDO-GNR films can be easily switched between the superhydrophobic anti-icing mode and the slippery deicing mode by applying the lubricant. A spray-coating method makes it suitable for large-scale applications. The anti-icing and deicing properties render the FDO-GNR films with promise for use in extreme environments.

Electro-impulse de-icing of a turbofan engine inlet

NASA Technical Reports Server (NTRS)

Zumwalt, G. W.

1985-01-01

The application of electromagnetic impulse deicing (EIDI) systems to turbofan engine inlets on business aircraft has been investigated experimentally. The tests were performed in the Icing Research Tunnel at NASA's Lewis Research Center. The deicing system testbed was a Falcon Fanjet 20 engine nacelle. The effectiveness of various deicing coil configurations and mount designs were compared, and design parameters were developed specifically for EIDI systems in turbofan engines. Flight tests were also carried out at altitudes in the range 3000-6000 ft corresponding to a temperature range of -3 to -8 C. It is shown that the ice particles removed from the engine inlet by the deicing system were small enough for the engine to ingest. Tentative design specifications are given with respect to the optimum coil configuration, and operating power of a EIDI production candidate.

Review of the FY15 Defense Environmental International Cooperation (DEIC) Program

DTIC Science & Technology

2016-03-01

Secretary of Defense for Energy, Installations and Environmental, Environmental Safety and Occupational Health [OASD (EI&E/ESOH)]. The views, opinions...DEIC Program The DEIC program, which resides within the Environment, Safety , and Occupational Health (ESOH) office of the Deputy Under Secretary of...resiliency, maritime safety and security, and environmental protection in general. 7 While this

Melting Frozen Droplets Using Photo-Thermal Traps

NASA Astrophysics Data System (ADS)

Dash, Susmita; de Ruiter, Jolet; Varanasi, Kripa

2017-11-01

Ice buildup is an operational and safety hazard in wind turbines, power lines, and airplanes. While traditional de-icing methods are energy-intensive or environmentally unfriendly, passive anti-icing approach using superhydrophobic surfaces fails under humid conditions, which necessitates development of passive deicing methods. Here, we investigate a passive technique for deicing using a multi-layer surface design that can efficiently absorb and convert the incident solar radiation to heat. The corresponding increase in substrate temperature allows for easy removal of frozen droplets from the surface. We demonstrate the deicing performance of the designed surface both at very low temperatures, and under frost and snow coverage.

Deicing System Protects General Aviation Aircraft

NASA Technical Reports Server (NTRS)

2007-01-01

Kelly Aerospace Thermal Systems LLC worked with researchers at Glenn Research Center on deicing technology with assistance from the Small Business Innovation Research (SBIR) program. Kelly Aerospace acquired Northcoast Technologies Ltd., a firm that had conducted work on a graphite foil heating element under a NASA SBIR contract and developed a lightweight, easy-to-install, reliable wing and tail deicing system. Kelly Aerospace engineers combined their experiences with those of the Northcoast engineers, leading to the certification and integration of a thermoelectric deicing system called Thermawing, a DC-powered air conditioner for single-engine aircraft called Thermacool, and high-output alternators to run them both. Thermawing, a reliable anti-icing and deicing system, allows pilots to safely fly through ice encounters and provides pilots of single-engine aircraft the heated wing technology usually reserved for larger, jet-powered craft. Thermacool, an innovative electric air conditioning system, uses a new compressor whose rotary pump design runs off an energy-efficient, brushless DC motor and allows pilots to use the air conditioner before the engine even starts

Review of the Fiscal Year 2014 (FY14) Defense Environmental International Cooperation (DEIC) Program

DTIC Science & Technology

2015-05-01

above, this spreadsheet lists all proposed projects by project number and title, the DEIC funds requested for each, the funding for approved projects...originating request, including DoD action officer, email address, and commercial and DSN phone number ; 3. Description – Explain why this...3 Numbers do not add to 100 percent (or $1,691,000) because they do not include funding to support overall DEIC

Detection of triazole deicing additives in soil samples from airports with low, mid, and large volume aircraft deicing activities.

PubMed

McNeill, K S; Cancilla, D A

2009-03-01

Soil samples from three USA airports representing low, mid, and large volume users of aircraft deicing fluids (ADAFs) were analyzed by LC/MS/MS for the presence of triazoles, a class of corrosion inhibitors historically used in ADAFs. Triazoles, specifically the 4-methyl-1H-benzotriazole and the 5-methyl-1H-benzotriazole, were detected in a majority of samples and ranged from 2.35 to 424.19 microg/kg. Previous studies have focused primarily on ground and surface water impacts of larger volume ADAF users. The detection of triazoles in soils at low volume ADAF use airports suggests that deicing activities may have a broader environmental impact than previously considered.

Modeling and strain gauging of eddy current repulsion deicing systems

NASA Technical Reports Server (NTRS)

Smith, Samuel O.

1993-01-01

Work described in this paper confirms and extends work done by Zumwalt, et al., on a variety of in-flight deicing systems that use eddy current repulsion for repelling ice. Two such systems are known as electro-impulse deicing (EIDI) and the eddy current repulsion deicing strip (EDS). Mathematical models for these systems are discussed for their capabilities and limitations. The author duplicates a particular model of the EDS. Theoretical voltage, current, and force results are compared directly to experimental results. Dynamic strain measurements results are presented for the EDS system. Dynamic strain measurements near EDS or EIDI coils are complicated by the high magnetic fields in the vicinity of the coils. High magnetic fields induce false voltage signals out of the gages.

Design of Aircraft Deicing Facilities

DOT National Transportation Integrated Search

1993-08-23

Archival copy of original Federal Aviation Administration standards and : specifications for use in the design of aircraft deicing facilities. To ensure : review of all changes, user should consult . ...

Review of the Fiscal Year 2013 (FY13) Defense Environmental International Cooperation (DEIC) Program

DTIC Science & Technology

2014-03-01

year. Of the remaining projects, the Advisory Group then identifies those projects that it feels merit support, but were not as high a priority... remaining 20 percent of the original budget. Thus, even if a project were listed for such funding, it would not necessarily be funded even if the full...DEIC program budget were available, since the total costs for such projects exceed the overall remaining DEIC budget (even before any cuts). This

Freezing points and small-scale deicing tests for salts of levulinic acid made from grain sorghum.

PubMed

Ganjyal, G; Fang, Q; Hanna, M A

2007-11-01

Deicers from renewable resources are needed to overcome the disadvantages of using traditional deicers. Salts made from levulinic acid produced using grain sorghum as raw material were tested as road deicing agents. Freezing points of these salts viz., sodium levulinate, magnesium levulinate and calcium levulinate along with rock salt (sodium chloride) were determined according to American Society for Testing and Materials (ASTM) D 1177-94 standard at concentrations of 10, 20, 30 and 40 % w/w. There were significant differences among the freezing points of the salts. Freezing points for rock salt, sodium levulinate, calcium levulinate and magnesium levulinate, for different concentrations, were in the ranges of -6.6 to -20.5, -2.9 to -15.0, -2.1 to -7.8 and -1.5 to -6.5 degrees C, respectively. Deicing effectiveness of the salts of levulinic acid were investigated by conducting small-scale deicing tests with aqueous solutions of various salt concentrations (2%, 5% and 10%) in a laboratory freezer and by spraying the deicer on a graveled surface covered by ice and snow with the average temperature during the testing at -2.7 degrees C. Deicing capabilities of the three salts of levulinic acid differed. At -2.7 degrees C, all three salts caused melting of the ice. Among the different levulinates studied sodium levulinate was the most effective deicing agent. These salts of levulinates could be a viable replacement for traditional deicers and could help in reducing the disadvantages of traditional deicers.

Analyses and tests for design of an electro-impulse de-icing system

NASA Technical Reports Server (NTRS)

Zumwalt, G. W.; Schrag, R. L.; Bernhart, W. D.; Friedberg, R. A.

1985-01-01

De-icing of aircraft by using the electro-magnetic impulse phenomenon was proposed and demonstrated in several European countries. However, it is not available as a developed system due to lack of research on the basic physical mechanisms and necessary design parameters. The de-icing is accomplished by rapidly discharging high voltage capacitors into a wire coil rigidly supported just inside the aircraft skin. Induced eddy currents in the skin create a repulsive force resulting in a hammer-like force which cracks, de-bonds, and expels ice on the skin surface. The promised advantages are very low energy, high reliability of de-icing, and low maintenance. Three years of Electo-Impulse De-icing (EIDI) research is summarized and the analytical studies and results of testing done in the laboratory, in the NASA Icing Research Tunnel, and in flight are presented. If properly designed, EIDI was demonstrated to be an effective and practical ice protection system for small aircraft, turbojet engine inlets, elements of transport aircraft, and shows promise for use on helicopter rotor blades. Included are practical techniques of fabrication of impulse coils and their mountings. The use of EIDI with nonmetallic surface materials is also described.

Suppression of radiating harmonics Electro-Impulse Deicing (EIDI) systems

NASA Astrophysics Data System (ADS)

Zieve, Peter; Ng, James; Fiedberg, Robert

1991-10-01

The electromagnetic compatibility (EMC) of two different configurations of electromagnetic deicing systems is discussed. Both Electro-Impulse Deicing (EIDI) and Eddy Current Repulsion Deicing Strip (EDS) are investigated. With EIDI, rigid coils are mounted behind the wing; while with EDS, the impulse coils are built thin and flexible with printed circuit board technology. An important consideration in the certification of electromagnetic impulse deicing systems is electromagnetic compatibility (EMC). When the capacitor bank discharges, a large current pulse travels down a transmission line to the coil. The coil is one source of radiation. Another source is the cabling and connections to the coil. In work conducted for the FAA in 1988, it was found that excessive electromagnetic emissions resulted from the operation of a Low Voltage Electro-Impulse Deicer (LVEID) in conjunction with a composite wing. The goal of this project was to investigate and develop techniques for controlling emissions without the benefit of shielding. In this study it was determined that both EIDI and EDS could be brought within the RTCA/DO-160B standards through proper shielding and termination of the pulse power cable. An alternative topology of EDS with the impulse coil on the wing exterior surface did not meet the standard.

Bridge deck deicing

DOT National Transportation Integrated Search

1998-01-01

Concrete bridge decks are prone to ice accumulation. The use of road salts and chemicals for deicing is cost effective but causes damage to concrete and corrosion of reinforcing steel in concrete bridge decks. This problem is a major concern to trans...

Deicing and Anti-Icing Unite

NASA Technical Reports Server (NTRS)

2002-01-01

With funding from Glenn's Small Business Innovation Research (SBIR) program, Cox & Company, Inc., built an ice protection system that combines thermal anti-icing and mechanical deicing to keep airfoils (wings and other lifting surfaces) clear of ice. Cox's concept was to combine an anti-icing system with NASA's Electro-Mechanical Expulsion Deicing System, a mechanical deicer. The anti-icing element of this hybrid would reduce the aerodynamic losses associated with deicing systems. The Cox Low Power Ice Protection System is the first new aircraft ice protection system that has been approved by the Federal Aviation Administration for use on a business jet in 40 years. While the system is currently sized for Premier class aircraft, there are no apparent constraints prohibiting its use on aircraft of any size. The company is investigating further applications, such as adapting the system for unmanned aerial vehicles and other military aircraft.

Assessment and management of aquatic impacts from airport de-icing activities -- The Canadian perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kent, R.A.; Andersen, D.; Simpson, A.

1995-12-31

Historically, aircraft deicing fluids have simply drained from aircraft and runway surfaces into airport drainage systems and invariably end up in surrounding receiving aquatic systems. This led to recent concerns over environmental impacts from glycol-based fluids typically used for deicing aircraft. Glycols from de-icing fluids have been detected at high levels at Canadian airports. Concern not only stems from the high volumes being used at relatively few point sources, but also to the higher toxicity of the formulated de-icing fluids, compared to pure glycols. As a result, significant environmental management efforts have been made at Canadian airports over the lastmore » 4 years, including extensive stormwater monitoring, glycol mitigation and pollution prevention plans. Site-specific mitigation plans have been implemented at 15 major Canadian airports which typically include glycol containment, collection and removal. While a reasonable dataset is available on the toxicity of pure glycols, much less information is available on the toxicity of formulated deicers. Furthermore, there have been very few field assessments of the aquatic impacts of de-icing. To date, management regimes developed to address the problem in Canada have focused almost exclusively on glycols and voluntary compliance to discharge limits and receiving water quality guidelines. This approach has resulted in reductions in the quantities of glycols which are released from Canadian airports into the surrounding environment. Currently, government and industry are refining this management system with an examination of new approaches and options such as more holistic airport wastewater quality assessments and toxicity-based guidelines.« less

Evaluation of an alternative deicing chemical vs. conventional sodium chloride.

DOT National Transportation Integrated Search

2004-07-01

A research project was initiated to evaluate the performance and cost effectiveness of a proprietary, pre-blended, : roadway-deicing chemical on New Hampshire highways. The evaluated material is a patented blend of sodium chloride, liquid : magnesium...

A feasibility study of bridge deck deicing using geothermal energy.

DOT National Transportation Integrated Search

2015-04-01

In this study, we investigated the feasibility of a ground-coupled system that utilizes heat energy harvested from the ground for : deicing of bridge decks. Heat exchange is performed using circulation loops integrated into the deep foundations suppo...

Documentation of liquid de-icing agents utilized during the winter of 2005-2006.

DOT National Transportation Integrated Search

2006-01-01

During the winter of 2005-2006, the Maine Department of Transportation (MaineDOT), Bureau of : Maintenance and Operations experimented with several liquid de-icing products designed to pre-wet : granular materials. This experimentation was undertaken...

Natural gas use is taking off

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kauffmann, B.G.

1995-07-01

The paper describes an infrared radiant heat process to de-ice aircraft. A typical 727 aircraft de-icing costs $2000--3000 using the current glycol method. The natural gas powered heater would only cost $400 per aircraft and would not pose the environmental problems that the glycol does. It is estimated that one Infratek system could consume 3.8 million cubic feet of natural gas each year during the de-icing season. Large airports might have as many as 10 units. 3.8 million cu. ft. of gas is equal to about 40 New York residential customers or eight New York commercial customers.

Environmental Aspects of Aircraft and Airfield Deicing - An Air Force Perspective

DTIC Science & Technology

2010-11-01

e l l e n c e COD of Aircraft Deicers ADF Kg O2/Kg compd Ethylene glycol 1.14 T Propylene glycol 1.47 T Isopropyl alcohol 2.11 T Neopentyl glycol ...showed that commercial airports use about 25 million gallons of Aircraft Deicing Fluid (ADF) annually, of which 22.1 M (88%) is Propylene Glycol (PG...S e r v i c e - E x c e l l e n c e AF Aircraft Deicing Overview 70% (107) of bases reported using aircraft deicers Propylene Glycol (PG), AMS 1424

Study of De-icing Salt Accumulation and Transport Through a Watershed

DOT National Transportation Integrated Search

2017-12-01

The accumulation of chloride in surface waters and groundwater from road deicing and other sources is a growing problem in northern cities of the U.S., including the Minneapolis-St. Paul metro area. To inform mitigation efforts, the transport of chlo...

14 CFR 23.1099 - Carburetor deicing fluid system detail design.

Code of Federal Regulations, 2012 CFR

2012-01-01

... fluid system must meet the applicable requirements for the design of a fuel system, except as specified... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Carburetor deicing fluid system detail... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

14 CFR 23.1099 - Carburetor deicing fluid system detail design.

Code of Federal Regulations, 2010 CFR

2010-01-01

... fluid system must meet the applicable requirements for the design of a fuel system, except as specified... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor deicing fluid system detail... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

14 CFR 23.1099 - Carburetor deicing fluid system detail design.

Code of Federal Regulations, 2013 CFR

2013-01-01

... fluid system must meet the applicable requirements for the design of a fuel system, except as specified... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Carburetor deicing fluid system detail... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

14 CFR 23.1099 - Carburetor deicing fluid system detail design.

Code of Federal Regulations, 2011 CFR

2011-01-01

... fluid system must meet the applicable requirements for the design of a fuel system, except as specified... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Carburetor deicing fluid system detail... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

14 CFR 23.1099 - Carburetor deicing fluid system detail design.

Code of Federal Regulations, 2014 CFR

2014-01-01

... fluid system must meet the applicable requirements for the design of a fuel system, except as specified... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Carburetor deicing fluid system detail... TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES...

Effects of highway deicing chemicals on shallow unconsolidated aquifers in Ohio--final report

USGS Publications Warehouse

Kunze, Allison E.; Sroka, Bernard N.

2004-01-01

As a result of concerns about salt intrusion into drinking water aquifers, the effects of highway deicing chemicals on shallow aquifers were studied at eight locations in Ohio from 1988 through 2002. The study was done by the U.S. Geological Survey, in cooperation with the Ohio Department of Transportation and the Federal Highway Administration. Sites were selected along major undivided highways where drainage is by open ditches and ground-water flow is approximately perpendicular to the highway. Records of deicer application rates were kept, and apparent movement of deicing chemicals through shallow, unconsolidated aquifers was monitored by means of periodic measurements of specific conductance and concentrations of dissolved sodium, calcium, and chloride. The State routes monitored were the following: State Route (SR) 3 in Ashland County, SR 84 in Ashtabula County, SR 29 in Champaign County, SR 4 in Clark County, SR 2 in Lucas County, SR 104 in Pickaway County, SR 14 in Portage County, and SR 97 in Richland County. The study began in 1988 with background data collection, extensive literature review, and site selection. This process, including drilling of wells at numerous test sites and the eight selected sites, lasted 3 years. Routine groundwater sampling at 4- to 6-week intervals began in January 1991 and continued through September 1999. A multilevel, passive flow ground-water sampling device was constructed and used. Other conditions monitored on a regular basis included ground-water level (monitored continuously), specific conductance, air and soil temperature, precipitation,chloride concentration in soil samples, and deicing-chemical application times and rates. Evidence from water analysis, specific-conductance measurements, and surface-geophysical measurements indicates that three of the eight sites (Ashtabula County, Lucas County, and Portage County sites) were affected by direct application of deicing chemicals. Climatic data collected during the study show that cold weather, and therefore deicing-chemical application rates, varied from south to north across the State. As a consequence, only minor traces of dissolved chloride (mean, 2443 mg/L (milligrams per liter)) above background concentrations (mean, 1323 mg/L) were determined in ground-water samples from the southernmost sites (approximately 39?30' to 40? N latitudeChampaign County, Clark County, and Pickaway County). At the Ashland and Richland County sites (approximately 40?30' N latitude), dissolved-chloride concentrations increased above background concentrations only intermittently (mean background concentrations 441 mg/L, rising to a mean of 4056 mg/L in downgradient wells). At the northernmost sites (41? 30' to 42? N latitudeLucas County, Portage County, and Ashtabula County), deicing-chemical application was consistent throughout the winter, and downgradient dissolved-chloride concentrations (mean, 124345 mg/L) rarely returned to background concentrations (mean, 737 mg/L) throughout the study period. Other factors than application rate that may affect the movement of deicing chemicals through an aquifer were precipitation amounts, the types of subsurface materials, ground-water velocity and gradient, hydraulic conductivity, soil type, land use, and Ohio Department of Transportation deicing priority.

Development of a cost-effective concrete bridge deck preservation program : volume 2--final results and recommendations.

DOT National Transportation Integrated Search

2016-07-01

The deterioration of bridge decks has been identified as a major problem in Indiana. The primary cause of this deterioration is salt water : ingress from the application of deicing salts during the winter. Deicing chemicals placed on the road mix wit...

Anti-icing and de-icing superhydrophobic concrete to improve the safety on critical elements on roadway pavements.

DOT National Transportation Integrated Search

2013-09-01

Icy roads lead to treacherous driving conditions in regions of the U.S. resulting in over 450 fatalities per year. Deicing chemicals, such as rock salt help to reduce ice formation on roadways to an extent, however also result in detrimental effects ...

De-Icing Salts and the Environment.

ERIC Educational Resources Information Center

Massachusetts Audubon Society, Lincoln.

Reported is an examination of the use and effects of chlorides as de-icing products for removal of snow and ice from roads immediately following storms. Increasing evidence of detrimental side effects led to a closer look and more careful evaluation of the overall significance of the so-called "bare pavement maintenance." The side…

Development of a cost-effective concrete bridge deck preservation program : volume 1--development and implementation of the experimental program.

DOT National Transportation Integrated Search

2016-07-01

The deterioration of bridge decks has been identified as a major problem in Indiana. The primary cause of this deterioration is salt water : ingress from the application of deicing salts during the winter. Deicing chemicals placed on the road mix wit...

14 CFR 29.1105 - Induction system screens.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Induction System § 29.1105 Induction system... screen may be in any part of the induction system that is the only passage through which air can reach the engine, unless it can be deiced by heated air; (c) No screen may be deiced by alcohol alone; and...

14 CFR 25.1105 - Induction system screens.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Induction System § 25.1105 Induction system... screen may be in any part of the induction system that is the only passage through which air can reach the engine, unless it can be deiced by heated air; (c) No screen may be deiced by alcohol alone; and...

Electrical resistivity tomography as monitoring tool for unsaturated zone transport: an example of preferential transport of deicing chemicals.

PubMed

Wehrer, Markus; Lissner, Heidi; Bloem, Esther; French, Helen; Totsche, Kai Uwe

2014-01-01

Non-invasive spatially resolved monitoring techniques may hold the key to observe heterogeneous flow and transport behavior of contaminants in soils. In this study, time-lapse electrical resistivity tomography (ERT) was employed during an infiltration experiment with deicing chemical in a small field lysimeter. Deicing chemicals like potassium formate, which frequently impact soils on airport sites, were infiltrated during snow melt. Chemical composition of seepage water and the electrical response was recorded over the spring period 2010. Time-lapse electrical resistivity tomographs are able to show the infiltration of the melt water loaded with ionic constituents of deicing chemicals and their degradation product hydrogen carbonate. The tomographs indicate early breakthrough behavior in parts of the profile. Groundtruthing with pore fluid conductivity and water content variations shows disagreement between expected and observed bulk conductivity. This was attributed to the different sampling volume of traditional methods and ERT due to a considerable fraction of immobile water in the soil. The results show that ERT can be used as a soil monitoring tool on airport sites if assisted by common soil monitoring techniques.

Impacts of road deicing salts on the early-life growth and development of a stream salmonid: Salt type matters.

PubMed

Hintz, William D; Relyea, Rick A

2017-04-01

The use of road deicing salts in regions that experience cold winters is increasing the salinity of freshwater ecosystems, which threatens freshwater resources. Yet, the impacts of environmentally relevant road salt concentrations on freshwater organisms are not well understood, particularly in stream ecosystems where salinization is most severe. We tested the impacts of deicing salts-sodium chloride (NaCl), magnesium chloride (MgCl 2 ), and calcium chloride (CaCl 2 )-on the growth and development of newly hatched rainbow trout (Oncorhynchus mykiss). We exposed rainbow trout to a wide range of environmentally relevant chloride concentrations (25, 230, 860, 1500, and 3000 mg Cl -  L -1 ) over an ecologically relevant time period (25 d). We found that the deicing salts studied had distinct effects. MgCl 2 did not affect rainbow trout growth at any concentration. NaCl had no effects at the lowest three concentrations, but rainbow trout length was reduced by 9% and mass by 27% at 3000 mg Cl -  L -1 . CaCl 2 affected rainbow trout growth at 860 mg Cl -  L -1 (5% reduced length; 16% reduced mass) and these effects became larger at higher concentrations (11% reduced length; 31% reduced mass). None of the deicing salts affected rainbow trout development. At sub-lethal and environmentally relevant concentrations, our results do not support the paradigm that MgCl 2 is the most toxic deicing salt to fish, perhaps due to hydration effects on the Mg 2+ cation. Our results do suggest different pathways for lethal and sub-lethal effects of road salts. Scaled to the population level, the reduced growth caused by NaCl and CaCl 2 at critical early-life stages has the potential to negatively affect salmonid recruitment and population dynamics. Our findings have implications for environmental policy and management strategies that aim to reduce the impacts of salinization on freshwater organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Aircraft de-icer: Recycling can cut carbon emissions in half

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Eric P., E-mail: ejohnson@ecosite.co.uk

Flight-safety regulations in most countries require aircraft to be ice-free upon takeoff. In icy weather, this means that the aircraft usually must be de-iced (existing ice is removed) and sometimes anti-iced (to protect against ice-reformation). For both processes, aircraft typically are sprayed with an 'antifreeze' solution, consisting mainly of glycol diluted with water. This de/anti-icing creates an impact on the environment, of which environmental regulators have grown increasingly conscious. The US Environmental Protection Agency (EPA), for example, recently introduced stricter rules that require airports above minimum size to collect de-icing effluents and send them to wastewater treatment. De-icer collection andmore » treatment is already done at most major airports, but a few have gone one step further: rather than putting the effluent to wastewater, they recycle it. This study examines the carbon savings that can be achieved by recycling de-icer. There are two key findings. One, recycling, as opposed to not recycling, cuts the footprint of aircraft de-icing by 40-50% - and even more, in regions where electricity-generation is cleaner. Two, recycling petrochemical-based de-icer generates a 15-30% lower footprint than using 'bio' de-icer without recycling. - Highlights: Black-Right-Pointing-Pointer Carbon footprint of aircraft de-icing can be measured. Black-Right-Pointing-Pointer Recycling aircraft de-icer cuts the footprint of aircraft de-icing by 40-50%. Black-Right-Pointing-Pointer Recycling 'fossil' de-icer is lower carbon than not recycling 'bio' de-icer.« less

A Flight Investigation of Exhaust-heat De-icing

NASA Technical Reports Server (NTRS)

Jones, Alun R; Rodert, Lewis A

1940-01-01

The National Advisory Committee for Aeronautics conducted exhaust-heat de-icing tests in flight to provide data needed in the application of this method. The capacity to extract heat from the exhaust gas for de-icing purposes, the quantity of heat required, and other factors were examined. The results indicate that a wing-heating system employing a spanwise exhaust tube within the leading edge of the wing removed 30 to 35 percent of the heat from exhaust gas entering the wing. Data are given from which the heat required for ice prevention can be calculated. Sample calculations have been made on the basis of existing engine power/wing area ratios to show that sufficient heating can be obtained for ice protection on modern transportation airplanes, provided that uniform distribution of the heat can be secured.

Demonstration of an Environmentally Benign and Reduced Corrosion Runway Deicing Fluid

DTIC Science & Technology

2011-01-01

43201 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) Enviromental Security Technology...laboratory to the airfields and airports across the country. Users may express concern because the Battelle-RDFs are new and they may have...airfield anti-icing and deicing at WPAFB. 1.3 REGULATORY DRIVERS There are several drivers for implementing a new , more environmentally friendly

Contamination of groundwater by outdoor highway deicing agent storage

NASA Astrophysics Data System (ADS)

Ostendorf, David W.; Hinlein, Erich S.; Rotaru, Camelia; DeGroot, Don J.

2006-07-01

This research quantifies the impact of outdoor highway deicing agent storage on groundwater quality. Data and theory realize the objective at a well characterized salt/premix storage facility on a glacial drumlin comprised of clayey sand till. Tritium and tritiogenic helium were observed in 17 monitoring wells in 2003, while chloride concentrations were measured in 43 monitoring wells from 1998 through 2004. The 3He/ 3H ratios confirm an analytical model of drumlin hydraulics (Ostendorf, D.W., DeGroot, D.J., Shelburne, W.M., and Mitchell, T.J., 2004. Hydraulic head in a clayey sand till over multiple timescales. Can. Geotech. J. 41, 89-105.), and support advective travel time estimates from the monitoring well screens back to the water table. An advective balance of recharge, precipitation, and surface runoff routes the water table Cl - concentrations inwards to the outdoor storage pile maintained at the site from the 1960s to the mid 1980s. Concentrations as high as 320 meq Cl -/L were observed in groundwater, although the deicing agent contamination had not yet reached the bottom of the drumlin in the study area. The travel time simulations yield a 200 meq Cl -/L water table isopleth in 1985 under the prior outdoor storage pile. The recharge concentration model matches the radial decrease of Cl - water table concentrations from the pile, and implies that 4400 kg of Cl - leached into the groundwater in 1985. This is about 0.3% of the deicing agent Cl - stored at the site each year. These results suggest that outdoor storage of highway deicing agents significantly impacted groundwater quality near the pile. The groundwater quality began to recover after source removal however: the leached Cl - flux dropped to 2,300 kg in 1992, more than 5 years after elimination of the outdoor storage pile.

De-icing of the altitude wind tunnel turning vanes by electro-magnetic impulse

NASA Technical Reports Server (NTRS)

Zumwalt, G. W.; Ross, R.

1986-01-01

The Altitude Wind Tunnel at the NASA-Lewis facility is being proposed for a refurbishment and moderization. Two major changes are: (1) the increasing of the test section Mach number to 0.90, and (2) the addition of spray nozzles to provide simulation of flight in icing clouds. Features to be retained are the simulation of atmospheric temperature and pressure to 50,000 foot altitude and provision for full-scale aircraft engine operation by the exhausting of the aircraft combustion gases and ingestion of air to replace that used in combustion. The first change required a re-design of the turning vanes in the two corners downstream of the test section due to the higher Mach number at the corners. The second change threatens the operation of the turning vanes by the expected ice build-up, particulary on the first-corner vanes. De-icing by heat has two drawbacks: (1) an extremely large amount of heat is required, and (2) the melted ice would tend to collect as ice on some other surfaces in the tunnel, namely, the tunnel propellers and the cooling coils. An alternate de-icing method had been under development for three years under NASA-Lewis grants to the Wichita State University. This report describes the electro-impulse de-icing (EIDI) method and the testing work done to assess its applicability to wind tunnel turning vane de-icing. Tests were conducted in the structural dynamics laboratory and in the NASA Icing Research Tunnel. Good ice protection was achieved at lower power consumption and at a wide range of tunnel operations conditions. Recommendations for design and construction of the system for this application of the EIDI method are given.

Effects of ion exchange on stream solute fluxes in a basin receiving highway deicing salts

USGS Publications Warehouse

Shanley, J.B.

1994-01-01

At Fever Brook, a 1260-ha forested basin in central Massachusetts, highway deicing salt application increased the solute flux in streamflow by 120% above background flux (equivalent basis) during a 2-yr period. Attempts to isolate the nonsalt component of stream solute fluxes have commonly subtracted salt contributions based on the net Cl flux (Cl output in streamflow minus Cl input in precipitation). In these studies, any net Na flux in excess of the amount needed to balance the net Cl flux has been attributed to weathering. At Fever Brook, however, the net output of Na was less than the net output of Cl, suggesting a loss of Na within the basin. The Na sink was inferred to be cation exchange of Na for Ca and Mg in the soil. A method was developed to quantify the exchange based on a Na budget, which included an independent estimate of the Na flux from weathering. The amount of exchange was apportioned to Ca and Mg based on their relative concentrations in the stream. The background fluxes of Ca and Mg (i.e., those that would occur in the absence of deicing salts) were calculated by subtracting the amounts from ion exchange plus the much smaller direct contributions in deicing salts from the observed fluxes. Ion exchange and direct salt contributions increased the net output fluxes of Ca and Mg, each by 44% above background. In basins that receive deicing salts, failure to account for cation exchange thus may result in an underestimate of the flux of Na from weathering and overestimates of the fluxes of Ca and Mg from weathering.

A study of ethylene glycol exposure and kidney function of aircraft de-icing workers.

PubMed

Gérin, M; Patrice, S; Bégin, D; Goldberg, M S; Vyskocil, A; Adib, G; Drolet, D; Viau, C

1997-01-01

Ethylene glycol levels were measured in 154 breathing zone air samples and in 117 urine samples of 33 aviation workers exposed to de-icing fluid (basket operators, de-icing truck drivers, leads and coordinators) studied during 42 worker-days over a winter period of 2 months at a Montreal airport. Ethylene glycol as vapour did not exceed 22 mg/m3 (mean duration of samples 50 min). Mist was quantified at higher levels in 3 samples concerning 1 coordinator and 2 basket operators (76-190 mg/m3, 45-118 min). In 16 cases workers' post-shift or next-morning urine contained quantities of ethylene glycol exceeding 5 mmol/mol creatinine (up to 129 mmol/mol creatinine), with most of these instances occurring in basket operators and coordinators, some of whom did not wear paper masks and/or were accidentally sprayed with de-icing fluid. Diethylene glycol was also found in a few air and urinary samples at levels around one tenth those of ethylene glycol. Urinary concentrations of albumin, beta-N-acetyl-glucosaminidase, beta-2-microglobulin and retinol-binding protein were measured and compared over various periods, according to subgroups based on exposure level and according to the frequency of extreme values. These analyses did not demonstrate acute or chronic kidney damage that could be attributed to working in the presence of ethylene glycol. In conclusion, this study does not suggest important health effects of exposure to de-icing fluid in this group of workers. Potential for overexposure exists, however, in certain work situations, and recommendations on preventive measures are given. In addition, these results suggest that other routes of absorption than inhalation, such as the percutaneous route, may be important and that urinary ethylene glycol may be a useful indicator of exposure to ethylene glycol.

Evaluation of activated sludge for biodegradation of propylene glycol as an aircraft deicing fluid.

PubMed

Delorit, Justin D; Racz, LeeAnn

2014-04-01

Aircraft deicing fluid used at airport facilities is often collected for treatment or disposal in order to prevent serious ecological threats to nearby surface waters. This study investigated lab scale degradation of propylene glycol, the active ingredient in a common aircraft deicing fluid, by way of a laboratory-scale sequencing batch reactor containing municipal waste water treatment facility activated sludge performing simultaneous organic carbon oxidation and nitrification. The ability of activated sludge to remove propylene glycol was evaluated by studying the biodegradation and sorption characteristics of propylene glycol in an activated sludge medium. The results indicate sorption may play a role in the fate of propylene glycol in AS, and the heterotrophic bacteria readily degrade this compound. Therefore, a field deployable bioreactor may be appropriate for use in flight line applications.

Development of Environmentally Benign and Reduced Corrosion Runway Deicing Fluid

DTIC Science & Technology

2009-08-01

PCNA Peter Cremer North America PG Propylene glycol P&G Proctor and Gamble Inc. PNNL Pacific Northwest National Laboratory RDF Runway Deicing...Navy/NAVAIR Defining Navy needs Mack Findley Peter Cremer North America (PCNA) Bio-based raw materials selection Pat Viani SMI AMS 1435 testing...SMI), and other laboratories under the leadership of SAE G-12 Fluids Subcommittee, and is expected to provide a better indication of compatibility with

Acute lung injury following refrigeration coil deicing.

PubMed

McKeown, Nathanael J; Burton, Brent T

2012-03-01

We report a case of a worker who developed ALI requiring mechanical ventilatory support after attempting to melt ice condensate by applying the flame of an oxy-acetylene torch to refrigeration coils charged with a halocarbon refrigerant in a closed environment. A discussion of possible etiologies are discussed, including phosgene, carbonyl fluoride, and nitrogen oxides. Primary prevention with adequate respiratory protection is recommended whenever deicing is performed in a closed space environment.

Review of the Fiscal Year 2014 (FY14) Defense Environmental International Cooperation (DEIC) Program

DTIC Science & Technology

2015-05-01

spell out) originating request, including DoD action officer, email address, and commercial and DSN phone number ; 3. Description...does not display a currently valid OMB control number . 1. REPORT DATE MAY 2015 2. REPORT TYPE 3. DATES COVERED 4. TITLE AND SUBTITLE Review...of the Fiscal Year 2014 (FY14) Defense Environmental International Cooperation (DEIC) Program 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM

Bioremediation of aircraft deicing fluids (glycol) at airports. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gallagher, D.W.

1998-09-01

This report describes the work done to determine the effectiveness of various aerobic bioremediation techniques for reducing the biochemical oxygen demand (BOD) of aircraft deicing fluid runoff. Primary emphasis has been placed on laboratory and field demonstrations of bioremediation systems using various combinations of inocula (bacteria), nutrient mixes, enzyme mixes, and ultrasonic stimulation. Laboratory experiments with a variety of inocula and nutrients together with enzymes and ultrasound are demonstrated showing the importance of the appropriate bacteria and nutrient mix in bioaugmentation. The appropriate mix was shown to significantly influence biodegradation. Deicing solutions were routinely reduced to acceptable BOD levels formore » effluent discharge in 3 days or less. In the field experiment, a special dual-tank bioreactor system was developed to demonstrate a pilot small-scale system. Experimental operation of this system confirmed that a 3-day or less remediation cycle was possible during the winter season.« less

Effects of highway deicing chemicals on shallow unconsolidated aquifers in Ohio, interim report, 1988-93

USGS Publications Warehouse

Jones, A.L.; Sroka, B.N.

1997-01-01

Effects of the application of highway deicing chemicals during winter months on ground- water quality are being studied by the U.S. Geological Survey in cooperation with the Ohio Department of Transportation and the Federal Highway Administration. Eight sites throughout the State were selected along major undivided highways where drainage is by open ditches and ground-water flow is approximately perpendicular to the highway. At these sites, records of deicer application rates are being kept and apparent movement of deicing chemicals through shallow, unconsolidated aquifers is being monitored by means of periodic measurements of specific con ductance and concentrations of dissolved sodium, calcium, and chloride. The counties and corre sponding sections of state routes being monitored are the following: State Route (SR) 3 in Ashland County, SR 84 in Ashtabula County, SR 29 in Champaign County, SR 4 in Clark County, SR 2 in Lucas County, SR 104 in Pickaway County, SR 14 in Portage County, and SR 97 in Richland County. The study began in January 1988 with background data collection, extensive literature review, and site selection. This process, including drilling of wells at the eight selected sites, lasted 3 years. Routine ground-water sampling at 4- to 6-week intervals began in January 1991. A relatively new type of multilevel, passive flow ground-water sampling device was constructed and used. Other conditions monitored on a regular basis included ground-water level (monitored con tinuously), specific conductance, air and soil temperature, precipitation, chloride concentration in soil samples, ground conductivity, and deicing chemical application times and rates. For the interim reporting period, water samples were collected from January 1991 through September 1993. Evidence from water analysis, specific conductance measurements, and surface geophysical measurements indicates that four of the eight sites (Ashtabula County, Lucas County, Portage County, and Richland County sites) are potentially affected by direct application of deic ing chemicals. Climatic data from the period January 1991 through September 1993 show that cold weather, and therefore deicing chemical application rates, varied widely across the State. As a consequence, only minor traces of dissolved chloride above background concentrations (mean, 12-25 mg/L) were determined in ground-water samples from the Pickaway County, Clark County, and Champaign County sites. At the Ashland and Richland County sites, dissolved chlo ride concentrations increased above background concentrations (from the upgradient well, pre sumably unaffected by road salt) only intermittently (mean background concentrations of 3-25 mg/L, rising to a mean of 49-77 mg/L). For the interim reporting period, the mean dissolved chloride concentration for all downgradient wells was about 2 times the background concentra tion (25mg/L) at the Ashland County site (50 mg/L) and 14 times the background concentration (3 mg/L) at the Richland County site (40 mg/L). At the Lucas County, Portage County, and Ash tabula County sites, deicing-chemical application was consistent throughout the winter, and downgradient dissolved chloride concentrations rarely returned to background concentrations (mean 6-32 mg/L) throughout the period. For the interim reporting period, the mean dissolved chloride concentration for all downgradient wells was about 3 times the background concentra tion at the Lucas County site (92 mg/L), 72 times the background concentration at the Portage County site (432 mg/L, 2 downgradient wells), and 21 times the background concentration at the Ashtabula County site (279 mg/L). Other factors that may affect the movement of deicing chemicals through the aquifer were examined, such as precipitation amounts; the types of subsurface materials; ground-water velocity and gradient; hydraulic conductivity; soil type; land use; and ODOT deicing priority. A final report is planned for 2001 afte

Road de-icing salt as a potential constraint on urban growth in the Greater Toronto Area, Canada

NASA Astrophysics Data System (ADS)

Howard, Ken W. F.; Maier, Herb

2007-04-01

North America's fifth most populated municipality — the Greater Toronto Area (GTA) — is undergoing rapid urban development with serious questions being raised regarding the long-term impacts of urban growth on the quality and quantity of ground and surface water. Degradation of groundwater quality by NaCl de-icing salt is the primary concern since there are no cost effective alternatives to NaCl de-icing salt and there is little evidence that salt loadings to the subsurface can be significantly reduced. In 2001, the issue acquired a new sense of urgency when de-icing chemicals containing inorganic chloride salts (with or without ferrocyanide de-caking agents) were designated as toxic under the Canadian Environmental Protection Act. To heighten concerns, future growth in the GTA will inevitably take place in areas where groundwater is regularly used for potable supply. Studies using groundwater flow and transport models show that significant deterioration of groundwater quality can be expected in shallow aquifers as a result of urban development with chloride concentrations approaching the drinking water quality standard of 250 mg/l. Results demonstrate that urban planning needs a fresh approach that explicitly includes groundwater protection and aquifer management in the decision-making process, clearly defines acceptable environmental performance standards and makes greater use of groundwater models to evaluate alternative urban designs.

Road de-icing salt as a potential constraint on urban growth in the Greater Toronto Area, Canada.

PubMed

Howard, Ken W F; Maier, Herb

2007-04-01

North America's fifth most populated municipality--the Greater Toronto Area (GTA)--is undergoing rapid urban development with serious questions being raised regarding the long-term impacts of urban growth on the quality and quantity of ground and surface water. Degradation of groundwater quality by NaCl de-icing salt is the primary concern since there are no cost effective alternatives to NaCl de-icing salt and there is little evidence that salt loadings to the subsurface can be significantly reduced. In 2001, the issue acquired a new sense of urgency when de-icing chemicals containing inorganic chloride salts (with or without ferrocyanide de-caking agents) were designated as toxic under the Canadian Environmental Protection Act. To heighten concerns, future growth in the GTA will inevitably take place in areas where groundwater is regularly used for potable supply. Studies using groundwater flow and transport models show that significant deterioration of groundwater quality can be expected in shallow aquifers as a result of urban development with chloride concentrations approaching the drinking water quality standard of 250 mg/l. Results demonstrate that urban planning needs a fresh approach that explicitly includes groundwater protection and aquifer management in the decision-making process, clearly defines acceptable environmental performance standards and makes greater use of groundwater models to evaluate alternative urban designs.

De-icing salt contamination reduces urban tree performance in structural soil cells.

PubMed

Ordóñez-Barona, Camilo; Sabetski, Vadim; Millward, Andrew A; Steenberg, James

2018-03-01

Salts used for de-icing roads and sidewalks in northern climates can have a significant impact on water quality and vegetation. Sub-surface engineering systems, such as structural soil cells, can regulate water runoff and pollutants, and provide the necessary soil volume and irrigation to grow trees. However, the ability of such systems to manage de-icing salt contamination, and the impact of this contamination on the trees growing in them, have not been evaluated. We report on an field investigation of de-icing salt contamination in structural cells in two street-revitalization projects in Toronto, Canada, and the impact of this contamination on tree performance. We analyzed soil chemistry and collected tree attributes; these data were examined together to understand the effect of salinity on tree mortality rates and foliar condition. Data collected from continuous soil salinity loggers from April to June for one of the two sites were used to determine whether there was a long-term accumulation of salts in the soils. Results for both sites indicate that both sites displayed high salinity and alkalinity, with levels elevated beyond those suggested before those reported to cause negative tree effects. For one site, trees that were alive and trees that had a better foliar condition had significantly lower levels of soil salinity and alkalinity than other trees. High salinity and alkalinity in the soil were also associated with lower nutrient levels for both sites. Although tests for salinity accumulation in the soils of one site were negative, a longer monitoring of the soil conditions within the soil cells is warranted. Despite structural cells being increasingly utilized for their dual role in storm-water management and tree establishment, there may be a considerable trade-off between storm-water management and urban-forest function in northern climates where de-icing salt application continues to be commonplace. Copyright © 2017 Elsevier Ltd. All rights reserved.

JUH-1H Redesigned Pneumatic Boot Deicing System Flight Test Evaluation

DTIC Science & Technology

1987-08-01

Company (BFG) Initiated a program to evaluate the feasibility of pneumatic deicing systems for helicopter rotor blades. The concept was revived by...Goodrich Company (BFG) polyurethane erosion material. All tubes 53 Photo 6. Control Switch V. in each delcer are simultaneously Inflated...laaaaaaaaaaaaaBBaaaa «••aaaaaaaffaaaaaaaaaaaaaaaaeaaaaaaaHaaaaaaaaaaa««««*«* a afiaa.a.aaaaaaaaaan a sa aa aaa ■ 8a»a saa B^iiBaBa ax ■ aa aaa aa aal .a

Flexural waves induced by electro-impulse deicing forces

NASA Technical Reports Server (NTRS)

Gien, P. H.

1990-01-01

The generation, reflection and propagation of flexural waves created by electroimpulsive deicing forces are demonstrated both experimentally and analytically in a thin circular plate and a thin semicylindrical shell. Analytical prediction of these waves with finite element models shows good correlation with acceleration and displacement measurements at discrete points on the structures studied. However, sensitivity to spurious flexural waves resulting from the spatial discretization of the structures is shown to be significant. Consideration is also given to composite structures as an extension of these studies.

Managing storm water at airports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halm, M.J.

1996-09-01

Airports are active facilities with numerous on-going operations at their sites. The following operations may adversely affect the water quality of nearby aquatic environments: De-icing runways; de-icing taxiways; de-icing and anti-icing aircraft; aircraft maintenance; and salt de-icer application. Until the amendments to the Clean Water Act of 1972, referred to as the Water Quality Act of 1987, were passed by Congress, the majority of storm water discharges in the US were unregulated. The Water Quality Act of 1987 was promulgated as an effort to manage the pollution resulting from storm water runoff. Many industrial facilities, especially airports, were faced withmore » complex problems in attempting to comply with these new federal regulations. National Pollution Discharge Elimination System (NPDES) permits for airports with more than 50,000 flight operations per year require periodic monitoring of receiving waters and storm sewer outfalls. The federal government has given states jurisdiction in issuing NPDES permits for storm water discharges. States may require composite or grab samples.« less

Road deicing salt irreversibly disrupts osmoregulation of salamander egg clutches.

PubMed

Karraker, Nancy E; Gibbs, James P

2011-03-01

It has been postulated that road deicing salts are sufficiently diluted by spring rains to ameliorate any physiological impacts to amphibians breeding in wetlands near roads. We tested this conjecture by exposing clutches of the spotted salamander (Ambystoma maculatum) to three chloride concentrations (1 mg/L, 145 mg/L, 945 mg/L) for nine days, then transferred clutches to control water for nine days, and measured change in mass at three-day intervals. We measured mass change because water uptake by clutches reduces risks to embryos associated with freezing, predation, and disease. Clutches in controls sequestered water asymptotically. Those in the moderate concentrations lost 18% mass initially and regained 14% after transfer to control water. Clutches in high concentration lost 33% mass and then lost an additional 8% after transfer. Our results suggest that spring rains do not ameliorate the effects of deicing salts in wetlands with extremely high chloride concentrations. Copyright © 2010 Elsevier Ltd. All rights reserved.

Lewis icing research tunnel test of the aerodynamic effects of aircraft ground deicing/anti-icing fluids

NASA Technical Reports Server (NTRS)

Runyan, L. James; Zierten, Thomas A.; Hill, Eugene G.; Addy, Harold E., Jr.

1992-01-01

A wind tunnel investigation of the effect of aircraft ground deicing/anti-icing fluids on the aerodynamic characteristics of a Boeing 737-200ADV airplane was conducted. The test was carried out in the NASA Lewis Icing Research Tunnel. Fluids tested include a Newtonian deicing fluid, three non-Newtonian anti-icing fluids commercially available during or before 1988, and eight new experimental non-Newtonian fluids developed by four fluid manufacturers. The results show that fluids remain on the wind after liftoff and cause a measurable lift loss and drag increase. These effects are dependent on the high-lift configuration and on the temperature. For a configuration with a high-lift leading-edge device, the fluid effect is largest at the maximum lift condition. The fluid aerodynamic effects are related to the magnitude of the fluid surface roughness, particularly in the first 30 percent chord. The experimental fluids show a significant reduction in aerodynamic effects.

Thin film eddy current impulse deicer

NASA Technical Reports Server (NTRS)

Smith, Samuel O.; Zieve, Peter B.

1990-01-01

Two new styles of electrical impulse deicers has been developed and tested in NASA's Icing Research Tunnel. With the Eddy Current Repulsion Deicing Boot (EDB), a thin and flexible spiral coil is encapsulated between two thicknesses of elastomer. The coil, made by an industrial printed circuit board manufacturer, is bonded to the aluminum aircraft leading edge. A capacitor bank is discharged through the coil. Induced eddy currents repel the coil from the aluminum aircraft structure and shed accumulated ice. A second configuration, the Eddy Current Repulsion Deicing-Strip (EDS) uses an outer metal erosion strip fastened over the coil. Opposite flowing eddy currents repel the strip and create the impulse deicing force. The outer strip serves as a surface for the collection and shedding of ice and does not require any structural properties. The EDS is suitable for composite aircraft structures. Both systems successfully dispelled over 95 percent of the accumulated ice from airfoils over the range of the FAA icing envelope.

Shape-Memory-Alloy-Based Deicing System Developed

NASA Technical Reports Server (NTRS)

1996-01-01

Ice buildup on aircraft leading edge surfaces has historically been a problem. Most conventional deicing systems rely either on surface heating to melt the accreted ice or pneumatic surface inflation to mechanically debond the ice. Deicers that rely solely on surface heating require large amounts of power. Pneumatic deicers usually cannot remove thin layers of ice and lack durability. Thus, there is a need for an advanced, low-power ice protection system. As part of the NASA Small Business and Innovation Research (SBIR) program, Innovative Dynamics, Inc., developed an aircraft deicing system that utilizes the properties of Shape Memory Alloys (SMA). The SMA-based system has achieved promising improvements in energy efficiency and durability over more conventional deicers. When they are thermally activated, SMA materials change shape; this is analogous to a conventional thermal expansion. The thermal input is currently applied via conventional technology, but there are plans to implement a passive thermal input that is supplied from the energy transfer due to the formation of the ice itself. The actively powered deicer was tested in the NASA Lewis Icing Research Tunnel on a powered rotating rig in early 1995. The system showed promise, deicing both rime and glaze ice shapes as thin as 1/8 in. The first prototype SMA deicer reduced power usage by 45 percent over existing electrothermal systems. This prototype system was targeted for rotorcraft system development. However, there are current plans underway to develop a fixed-wing version of the deicer.

An investigation on the deicing of helicopter blades using shear horizontal guided waves

NASA Astrophysics Data System (ADS)

Ramanathan, Srinivasan

Despite all the advances that have made air travel safer than ever, the accumulation of ice on airplane and rotorcraft wings continues to be one of aviation's most challenging problems. Hence the presence of a reliable and efficient deicing or anti-icing system is imperative for their safe operation. The current method used to deice helicopter blades is similar to that available in automobile rear windows. These electro-thermal systems consist of heating coils that run along the span or chord of the rotor-blade. A current source connected via a slip ring configuration heats the coils, which in turn melt the ice on the surface. Due to their enormous power consumption, electro-thermal systems are generally configured to deice one foot of one blade at a time. This makes it hazardous to fly the helicopters under severe icing conditions. Even with the energy saving deicing procedure the electrical power required substantially exceeds the normal helicopter electrical system capacity, necessitating a large secondary electrical system with redundant, dual alternator features. The electro-thermal system for the Bell 412 helicopter weighed 162 lbs and required 26 kW of power for 2 blades! Various types of deicing systems were compared in chapter 1 and electromechanical systems were found to be the most energy efficient and practical for in-flight conditions. A novel approach of breaking the ice-substrate bonds by exceeding their adhesive strength using guided shear horizontal waves was chosen as the deicing mechanism. A comparison of the different electro-mechanical actuation systems pointed towards monolithic shear mode piezoelectric actuators as the choice that would satisfy the energy and dimensional requirements. A survey of literature on the mechanics of ice adhesion, in chapter 2, led to the selection of 1.42MPa as the target adhesive bond strength for the refrigerated icealuminum interface. The static adhesive strength of naturally occurring forms of ice such as rime ice and glaze ice to aluminum (0.12MPa and 0.4MPa respectively) is much lower than that of the refrigerated ice-aluminum adhesive strength (1.42MPa). Therefore, selecting the static adhesive strength of the refrigerated ice-aluminum interface as the bond strength to overcome would enable the system to deice rotor-blades under natural icing conditions. Equivalent circuit analysis was applied to the actuator, aluminum plate and ice layer system to determine an expression for the shear stress at the ice aluminum interface per unit excitation voltage supplied to the actuator and the corresponding electrical power consumed. All the parameters that affected the stress at the ice-aluminum interface were identified from the equivalent circuit model of the system. The parameters were split into control (can be actively changed by user) parameters and material (no user control over the variation of these parameter due to temperature and electric field) parameters. A statistical approach (Design of Experiments) was used to determine the control parameter settings that resulted in the maximum shear stress at the ice aluminum interface per unit actuator excitation voltage. A material parameter design of experiments was carried out to determine the effect of the deviation in the variable parameters on the stress at the ice-aluminum interface and actuator power consumption. A simplified approach to calculate the shear piezoelectric actuator losses under high excitation fields was presented. The experimental results indicated that the adhesive shear strength of the ice-aluminum bond under high frequency dynamic loads is much lower that its static adhesive strength. This was proved by the fact that the ice-aluminum interface bonds were broken at stress values of 0.73MPa as opposed to the target 1.42Mpa. This can be attributed to inherently stochastic nature of ice and the fact that the ice-aluminum bond fails at a much lower stress under dynamic loading as opposed to static loading. The shear mode actuator has a projected power consumption of 0.6kW for the twin bladed Bell 412 (assuming 6 actuators per foot per blade each consuming 50W) if deiced by station as opposed to 26kW for a corresponding electro-thermal system. The shear mode actuator has a projected power consumption of 3.6kW if both blades are deiced simultaneously over the desired length (1/3 rd span from the root) as required in severe icing conditions. The piezoelectric shear mode actuation system (estimated weight of 50 lbs with the actuators themselves accounting for less than 1 lb.) has the potential of delivering this performance while being 70% lighter than a comparable electro-thermal system (weight of 162 lbs). (Abstract shortened by UMI.)

Electro-impulse de-icing testing analysis and design

NASA Technical Reports Server (NTRS)

Zumwalt, G. W.; Schrag, R. L.; Bernhart, W. D.; Friedberg, R. A.

1988-01-01

Electro-Impulse De-Icing (EIDI) is a method of ice removal by sharp blows delivered by a transient electromagnetic field. Detailed results are given for studies of the electrodynamic phenomena. Structural dynamic tests and computations are described. Also reported are ten sets of tests at NASA's Icing Research Tunnel and flight tests by NASA and Cessna Aircraft Company. Fabrication of system components are described and illustrated. Fatigue and electromagnetic interference tests are reported. Here, the necessary information for the design of an EIDI system for aircraft is provided.

Laboratory-scale evaluation of a combined soil amendment for the enhanced biodegradation of propylene glycol-based aircraft de-icing fluids.

PubMed

Libisch, Balázs; French, Helen K; Hartnik, Thomas; Anton, Attila; Biró, Borbála

2012-01-01

A combined soil amendment was tested in microcosm experiments with an aim to enhance the aerobic biodegradation of propylene glycol (PG)-based aircraft de-icing fluids during and following the infiltration of contaminated snowmelt. A key objective under field conditions is to increase degradation of organic pollutants in the surface soil where higher microbial activity and plant rhizosphere effects may contribute to a more efficient biodegradation of PG, compared to subsoil ground layers, where electron acceptors and nutrients are often depleted. Microcosm experiments were set up in Petri dishes using 50 g of soil mixed with appropriate additives. The samples contained an initial de-icing fluid concentration of 10,000 mg/kg soil. A combined amendment using calcium peroxide, activated carbon and 1 x Hoagland solution resulted in significantly higher degradation rates for PG both at 4 and 22 degrees C. Most probable numbers of bacteria capable of utilizing 10,000 mg/kg de-icing fluid as a sole carbon source were about two orders of magnitude higher in the amended soil samples compared to unamended controls at both temperatures. The elevated numbers of such bacteria in surface soil may be a source of cells transported to the subsoil by snowmelt infiltration. The near-surface application of amendments tested here may enhance the growth of plants and plant roots in the contaminated area, as well as microbes to be found at greater depth, and hence increase the degradation of a contaminant plume present in the ground.

Increasing Base Cations in Streams: Another Legacy of Deicing Salts?

NASA Astrophysics Data System (ADS)

Helton, A. M.; Barclay, J. R.; Bellucci, C.; Rittenhouse, C.

2017-12-01

Elevated use of deicing salts directly increases sodium chloride inputs to watersheds. Sodium can accumulate in soils over time and has the potential to leach other cations (e.g., calcium, magnesium, and potassium) from the soil through cation exchange. We hypothesize that increased use of deicing salts results in a legacy of soils depleted in non-sodium base cations with loss of cations to receiving waters. The goal of this project is to quantify temporal trends in base cations and chloride in streams and rivers across the United States. We used Weighted Regressions on Time, Discharge, and Season (WRTDS) to analyze trends in base cations. Our preliminary analysis of 10 rivers in Connecticut with chemical periods of record ranging from 24 - 64 years (median = 55 years), shows that the flux of base cations is increasing in all sites (25 - 366 103 meq ha-1 yr-1 yr-1), driven largely by increases in sodium (23 - 222 103 meq ha-1 yr-1 yr-1), the dominant cation in 7 of the sites. Chloride is also increasing at all sites (26 - 261 103 meq ha-1 yr-1 yr-1), which, in combination with salt use trends, suggests a road salt source for the increased sodium. Non-sodium cations are also increasing in 9 of the sites (8 - 54 103 meq ha-1 yr-1 yr-1), though they are not directly added with most deicing salts. We will compare these trends to other long-term sites across the United States, and quantify relationships between cation trends and land cover, road density, and snowfall.

The influence of supraglacial debris cover variability on de-icing processes - examples from Svalbard

NASA Astrophysics Data System (ADS)

Lukas, Sven; Benn, Douglas I.; Boston, Clare M.; Hawkins, Jack; Lehane, Niall E.; Lovell, Harold; Rooke, Michael

2014-05-01

Extensive supraglacial debris covers are widespread near the margins of many cold-based and polythermal surging and non-surging glaciers in Svalbard. Despite their importance for current glacier dynamics and a detailed understanding of how they will affect the de-icing of ice-marginal areas, little work has been carried out to shed light on the sedimentary processes operating in these debris covers. We here present data from five different forelands in Svalbard. In all five cases, surfaces within the debris cover can be regarded as stable where debris cover thickness exceeds that of the active layer; vegetation development and absence of buried ice exposures at the surface support this conclusion, although test pits and geophysical investigations have revealed the presence of buried ice at greater depths (> 1-3 m). These findings imply that even seemingly stable surfaces at present will be subject to change by de-icing in the future. Factors and processes that contribute towards a switch from temporarily stable to unstable conditions have been identified as: 1. The proximity to englacial or supraglacial meltwater channels. These channels enlarge due to thermo-erosion, which can lead to the eventual collapse of tunnel roofs and the sudden generation of linear instabilities in the system. Along such channels, ablation is enhanced compared to adjacent debris-covered ice, and continued thermo-erosion continuously exposes new areas of buried ice at the surface. This works in conjunction with 2. Debris flows that occur on all sloping ground and transfer material from stable to less stable (sloping) locations within the debris cover and eventually into supraglacial channels, from where material is then removed from the system. Several generations of debris flows have been identified in all five debris covers, strongly suggesting that these processes are episodic and that the loci of these processes switch. This in turn indicates that transfer of material by debris flows downslope can lead to localised thickening of the debris cover, thereby resulting in the creation of new temporarily-stable areas in downslope locations. 3. The renewed and continued re-distribution of material causes de-icing to proceed in a stepwise fashion. While de-icing is ongoing, this results in the formation of debris cones or even larger ridges and mounds that have been termed "moraine-mound complexes" by previous workers (e.g. Graham et al., 2007). These are temporary landforms that will not survive de-icing over longer timescales, and projection of continued reworking into the future shows that perhaps an undulating spread of material will remain (cf. Lukas, 2007). The formation of supraglacial lakes during overall melting can lead to the formation of thick sequences of sorted sediments that in turn insulate the underlying ice after lake drainage. The presence of such sorted sediments in current ridge-top locations in some of the debris covers gives further weight to the interpretation of a mode of stepwise de-icing; crumbling and erosion by snowmelt and wind attests the shortlived nature of such deposits in topographic highs. Our findings strongly support an interpretation of a de-icing mode that takes place in a stepwise fashion that leads to several generations of sediment transfer within the debris covers and repeated relief inversion. References Graham, D.J., Bennett, M.R., Glasser, N.F., Hambrey, M.J., Huddart, D., Midgley, N.G., 2007. 'A test of the englacial thrusting hypothesis of ''hummocky''moraine formation: case studies from the northwest Highlands, Scotland': Comments. Boreas 36, 103-107. Lukas, S., 2007. Englacial thrusting and (hummocky) moraine formation: a reply to comments by Graham et al. (2007). Boreas 36, 108-113.

Study of the De-Icing Properties of the ASDE-3 Rotodome.

DTIC Science & Technology

1982-04-01

Heat Transfer Coefficients ........................... 3 -18 3.2.3 Prediction of De-Icing Capability ...... 3 -23 3.2.4 Calculation of Mean DIA & PATH...kVA 3 -31 N NUL =ti: :6 i ::p :: %:::::28 -R) [ eN 23,100t Averaged for Laminar & Turbulent Regimes. SAssuming a transition from Laminar to. Turbulent...Calculation of Mean Dia .& Path Length for Roof Mean Path Length for Roof: y 4r 4x 9 3.82 ft 3 x 7 1 2(92 3.8221/2 1 = 2(92 - 3.822 = 8.15 ft x 2 16.3 ft 16.3

Electro-impulse de-icing electrodynamic solution by discrete elements

NASA Technical Reports Server (NTRS)

Bernhart, W. D.; Schrag, R. L.

1988-01-01

This paper describes a technique for analyzing the electrodynamic phenomena associated with electro-impulse deicing. The analysis is done in the time domain and utilizes a discrete element formulation concept expressed in state variable form. Calculated results include coil current, eddy currents in the target (aircraft leading edge skin), pressure distribution on the target, and total force and impulse on the target. Typical results are presented and described. Some comparisons are made between calculated and experimental results, and also between calculated values from other theoretical approaches. Application to the problem of a nonrigid target is treated briefly.

Heavy metal removal mechanisms of sorptive filter materials for road runoff treatment and remobilization under de-icing salt applications.

PubMed

Huber, Maximilian; Hilbig, Harald; Badenberg, Sophia C; Fassnacht, Julius; Drewes, Jörg E; Helmreich, Brigitte

2016-10-01

The objective of this research study was to elucidate the removal and remobilization behaviors of five heavy metals (i.e., Cd, Cu, Ni, Pb, and Zn) that had been fixed onto sorptive filter materials used in decentralized stormwater treatment systems receiving traffic area runoff. Six filter materials (i.e., granular activated carbon, a mixture of granular activated alumina and porous concrete, granular activated lignite, half-burnt dolomite, and two granular ferric hydroxides) were evaluated in column experiments. First, a simultaneous preloading with the heavy metals was performed for each filter material. Subsequently, the remobilization effect was tested by three de-icing salt experiments in duplicate using pure NaCl, a mixture of NaCl and CaCl2, and a mixture of NaCl and MgCl2. Three layers of each column were separated to specify the attenuation of heavy metals as a function of depth. Cu and Pb were retained best by most of the selected filter materials, and Cu was often released the least of all metals by the three de-icing salts. The mixture of NaCl and CaCl2 resulted in a stronger effect upon remobilization than the other two de-icing salts. For the material with the highest retention, the effect of the preloading level upon remobilization was measured. The removal mechanisms of all filter materials were determined by advanced laboratory methods. For example, the different intrusions of heavy metals into the particles were determined. Findings of this study can result in improved filter materials used in decentralized stormwater treatment systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

An Investigation Utilizing an Electrical Analogue of Cyclic Deicing of a Hollow Steel Propeller with an External Blade Shoe

NASA Technical Reports Server (NTRS)

Neel, Carr B., Jr.

1952-01-01

A study has been made of the heat requirement for the cyclic de-icing of hollow steel propellers fitted with external blade heating shoes. Solutions to the equations for the heat flow in cyclic heating of propellers were obtained, using an electrical analogy. The study showed how the energy requirement for propeller de-icing with existing blade shoes could be decreased, and illustrated the effect of blade-shoe design on the energy requirement. It was demonstrated, for example, that by increasing the heating intensity and decreasing the heating period from those currently used the energy requirement could be decreased in the order of 60 percent. ' In addition, ft was shown that heating requirements could be decreased further, by as much as 60 percent, through proper design of the shoes. The' investigation also showed the energy requirement to increase with decreasing liquid-water content and air temperature. Uncertainties as to the exact values of convective heat-transfer coefficient prevailing over the surface of the blade and ice layer resulted in uncertainties of approximately proportional magnitude in the values of required heating intensity.

Synthesis and Properties of a Clean and Sustainable Deicing Additive for Asphalt Mixture

PubMed Central

Peng, Chao; Yu, Jianying; Zhao, Zhijie; Dai, Jing; Fu, Jingyi; Zhao, Meiling; Wang, Wei

2015-01-01

A clean and sustainable deicing additive was prepared via the adsorption of acetate anions (Ac-) by magnesium (Mg) and aluminum (Al) calcined layered double hydroxide (Mg/Al-CLDH). Fourier transform infrared spectroscopy spectrums proved that Ac- had intercalated into LDH structure. X-ray diffraction patterns, scanning electron microscopy and transmission electron microscopy images showed that the intercalation spacing and platelet thickness of Mg and Al layered double hydroxide containing Ac- anions (Mg/Al-Ac- LDH) had been enlarged due to substitution of divalent CO3 2- anions by a larger quantity of monovalent Ac– anions. Differential scanning calorimetry tests testified that the insoluble Mg2/Al-Ac- LDH evidently decreased the freeze point (FP) of water to -10.68°C. X-ray photoelectron spectroscopy analyses confirmed that the Ac- were strongly confined by the metal layers of LDHs. FP test of asphalt mixtures confirmed that Mg/Al-Ac- LDHs reduced FP to -5.5°C. Immersion test results indicated that Mg/Al-Ac- LDH had a good deicing durability and Ac- did not released from asphalt mixture. Snow melting observation was conducted further testified that Mg/Al-Ac- LDH melted snow or ice sustainably. PMID:25625279

Synthesis and properties of a clean and sustainable deicing additive for asphalt mixture.

PubMed

Peng, Chao; Yu, Jianying; Zhao, Zhijie; Dai, Jing; Fu, Jingyi; Zhao, Meiling; Wang, Wei

2015-01-01

A clean and sustainable deicing additive was prepared via the adsorption of acetate anions (Ac-) by magnesium (Mg) and aluminum (Al) calcined layered double hydroxide (Mg/Al-CLDH). Fourier transform infrared spectroscopy spectrums proved that Ac- had intercalated into LDH structure. X-ray diffraction patterns, scanning electron microscopy and transmission electron microscopy images showed that the intercalation spacing and platelet thickness of Mg and Al layered double hydroxide containing Ac- anions (Mg/Al-Ac- LDH) had been enlarged due to substitution of divalent CO32- anions by a larger quantity of monovalent Ac- anions. Differential scanning calorimetry tests testified that the insoluble Mg2/Al-Ac- LDH evidently decreased the freeze point (FP) of water to -10.68°C. X-ray photoelectron spectroscopy analyses confirmed that the Ac- were strongly confined by the metal layers of LDHs. FP test of asphalt mixtures confirmed that Mg/Al-Ac- LDHs reduced FP to -5.5°C. Immersion test results indicated that Mg/Al-Ac- LDH had a good deicing durability and Ac- did not released from asphalt mixture. Snow melting observation was conducted further testified that Mg/Al-Ac- LDH melted snow or ice sustainably.

Spontaneous De-Icing Phenomena on Extremely Cold Surfaces

NASA Astrophysics Data System (ADS)

Song, Dong; Choi, Chang-Hwan

2017-11-01

Freezing of droplets on cold surfaces is universal phenomenon, while the mechanisms are still inadequately understood. Here we report spontaneous de-icing phenomena of an impacting droplet which occur on extreme cold surfaces. When a droplet impacts on cold surfaces lower than -80°, it takes more than two times longer for the droplet to freeze than the ones at -50°. Moreover, the frozen droplet below -80° breaks up into several large parts spontaneously in the end. When a droplet impacts on the extreme cold surfaces, evaporation and condensation occur immediately as the droplet approaches the substrate. A thick layer of frost forms between the droplet and substrate, decreasing the contact area of the droplet with substrate. It leads to impede the heat transfer and hence extends the freezing time significantly. On the extremely cold substrate, the droplet freezes from the center to the edge area, in contrast to a typical case freezing from the bottom to the top. This novel from-center-to-edge freezing process changes the internal tension of the frozen droplet and results in the instantaneous breakup and release eventually, which can be taken advantage of for effective deicing mechanisms.

Theoretical analysis of the electrical aspects of the basic electro-impulse problem in aircraft de-icing applications

NASA Technical Reports Server (NTRS)

Henderson, R. A.; Schrag, R. L.

1986-01-01

A summary of modeling the electrical system aspects of a coil and metal target configuration resembling a practical electro-impulse deicing (EIDI) installation, and a simple circuit for providing energy to the coil, was presented. The model was developed in sufficient theoretical detail to allow the generation of computer algorithms for the current in the coil, the magnetic induction on both surfaces of the target, the force between the coil and target, and the impulse delivered to the target. These algorithms were applied to a specific prototype EIDI test system for which the current, magnetic fields near the target surfaces, and impulse were previously measured.

Oxidized starch solutions for environmentally friendly aircraft deicers.

PubMed

Plahuta, Joseph M; Teel, Amy L; Ahmad, Mushtaque; Beutel, Mark W; Rentz, Jeremy A; Watts, Richard J

2011-09-01

Deicers currently used for aircraft deicing, including ethylene glycol and propylene glycol, pose significant threats to surface waters, as a result of high biochemical oxygen demand (BOD) and toxicity to aquatic organisms. Oxidized starch may provide a less toxic deicer with lower BOD. The freezing point depression of starch formulations oxidized using hydrogen peroxide and catalysts (i.e., catalyzed hydrogen peroxide [H2O2] propagations-CHP) was 28 degrees C, and viscosities similar to those of commercial deicers were achieved after post-treatment with granular activated carbon. The most effective oxidized starch formulation exerted a 5-day BOD up to 6 times lower than glycol deicers (103 versus 400 to 800 g O2/L). Toxicity to Ceriodaphnia dubia for this formulation (48-hour lethal concentration, 50% [LC50] of 2.73 g/L) was greater than pure propylene glycol (13.1 g/ L), but lower than propylene glycol deicer formulations (1.02 g/L). Organic acids were identified by gas chromatography/mass spectrometry as the primary constituents in the oxidized starch solution. The proposed deicing system would provide effective deicing while exerting minimal environmental effects (e.g., lower toxicity to aquatic organisms and lower BOD). Furthermore, these deicers could be made from waste starch, promoting sustainability.

The Evaluation of Damage Effects on MgO Added Concrete with Slag Cement Exposed to Calcium Chloride Deicing Salt.

PubMed

Jang, Jae-Kyeong; Kim, Hong-Gi; Kim, Jun-Hyeong; Ryou, Jae-Suk

2018-05-14

Concrete systems exposed to deicers are damaged in physical and chemical ways. In mitigating the damage from CaCl₂ deicers, the usage of ground slag cement and MgO are investigated. Ordinary Portland cement (OPC) and slag cement are used in different proportions as the binding material, and MgO in doses of 0%, 5%, 7%, and 10% are added to the systems. After 28 days of water-curing, the specimens are immersed in 30% CaCl₂ solution by mass for 180 days. Compressive strength test, carbonation test, chloride penetration test, chloride content test, XRD analysis, and SEM-EDAX analysis are conducted to evaluate the damage effects of the deicing solution. Up to 28 days, plain specimens with increasing MgO show a decrease in compressive strength, an increase in carbonation resistance, and a decrease in chloride penetration resistance, whereas the S30- and S50- specimens show a slight increase in compressive strength, an increase in carbonation resistance, and a slight increase in chloride penetration resistance. After 180 days of immersion in deicing solution, specimens with MgO retain their compressive strength longer and show improved durability. Furthermore, the addition of MgO to concrete systems with slag cement induces the formation of magnesium silicate hydrate (M-S-H) phases.

Multifunctional carbon nano-paper composite

NASA Astrophysics Data System (ADS)

Zhang, Zhichun; Chu, Hetao; Wang, Kuiwen; Liu, Yanjv; Leng, Jinsong

2013-08-01

Carbon Nanotube (CNT), for its excellent mechanical, electrical properties and nano size, large special surface physical property, become the most promising material. But carbon nanotube can still fabricated in micro dimension, and can't be made into macro size, so to the carbon nanotube filled composite can't explore the properties of the CNT. Carbon nano-paper is made of pure CNT, with micro pore, and it turn micro sized CNT into macro shaped membrane. Based on the piezo-resistivity and electrical conductivity of the carbon nano-paper, we used the carbon nano-paper as functional layers fabricate functional composite, and studies its strain sensing, composite material deicing and shape memory polymer (SMP) material electric actuation performance. The results shown that the resin can pregnant the nano paper, and there was good bond for nano paper and composite. The functional composite can monitoring the strain with high sensitivity comparing to foil strain gauge. The functional composite can be heated via the carbon nano paper with low power supply and high heating rate. The composite has good deicing and heat actuation performance to composite material. For the good strain sensing, electric conductivity and self-heating character of the carbon nano-paper composite, it can be used for self sensing, anti lightning strike and deicing of composite materials in aircrafts and wind turbine blades.

FIRE_AX_SOF_ARAT_FLT

Atmospheric Science Data Center

2015-11-25

... Microwave Radiometer Optical Counter Platinum Resistance Pyranometer Pyrgeometer Variable Capacitance ... Parameters:  Aerosol Particle Properties Air Temperature Cloud Liquid Water Deiced Temperature Dew Point Doppler ...

Highway deicing salt dynamic runoff to surface water and subsequent infiltration to groundwater during severe UK winters.

PubMed

Rivett, Michael O; Cuthbert, Mark O; Gamble, Richard; Connon, Lucy E; Pearson, Andrew; Shepley, Martin G; Davis, John

2016-09-15

Dynamic impact to the water environment of deicing salt application at a major highway (motorway) interchange in the UK is quantitatively evaluated for two recent severe UK winters. The contaminant transport pathway studied allowed controls on dynamic highway runoff and storm-sewer discharge to a receiving stream and its subsequent leakage to an underlying sandstone aquifer, including possible contribution to long-term chloride increases in supply wells, to be evaluated. Logged stream electrical-conductivity (EC) to estimate chloride concentrations, stream flow, climate and motorway salt application data were used to assess salt fate. Stream loading was responsive to salt applications and climate variability influencing salt release. Chloride (via EC) was predicted to exceed the stream Environmental Quality Standard (250mg/l) for 33% and 18% of the two winters. Maximum stream concentrations (3500mg/l, 15% sea water salinity) were ascribed to salt-induced melting and drainage of highway snowfall without dilution from, still frozen, catchment water. Salt persistance on the highway under dry-cold conditions was inferred from stream observations of delayed salt removal. Streambed and stream-loss data demonstrated chloride infiltration could occur to the underlying aquifer with mild and severe winter stream leakage estimated to account for 21 to 54% respectively of the 70t of increased chloride (over baseline) annually abstracted by supply wells. Deicing salt infiltration lateral to the highway alongside other urban/natural sources were inferred to contribute the shortfall. Challenges in quantifying chloride mass/fluxes (flow gauge accuracy at high flows, salt loading from other roads, weaker chloride-EC correlation at low concentrations), may be largely overcome by modest investment in enhanced data acquisition or minor approach modification. The increased understanding of deicing salt dynamic loading to the water environment obtained is relevant to improved groundwater resource management, highway salt application practice, surface-water - ecosystem management, and decision making on highway drainage to ground. Copyright © 2016 Elsevier B.V. All rights reserved.

Numerical simulation of two-dimensional heat transfer in composite bodies with application to de-icing of aircraft components. Ph.D. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Chao, D. F. K.

1983-01-01

Transient, numerical simulations of the de-icing of composite aircraft components by electrothermal heating were performed for a two dimensional rectangular geometry. The implicit Crank-Nicolson formulation was used to insure stability of the finite-difference heat conduction equations and the phase change in the ice layer was simulated using the Enthalpy method. The Gauss-Seidel point iterative method was used to solve the system of difference equations. Numerical solutions illustrating de-icer performance for various composite aircraft structures and environmental conditions are presented. Comparisons are made with previous studies. The simulation can also be used to solve a variety of other heat conduction problems involving composite bodies.

Characterization of Polymer-Coated MEMS Humidity Sensors for Flight Applications

NASA Technical Reports Server (NTRS)

Shams, Qamar A.; Burkett, Cecil G., Jr.; Daniels, Taumi S.; Tsoucalas, George; Comeaux, Toby; Sealey, Bradley S.; Fox, Melanie L.

2005-01-01

Under NASA's Aviation Safety Program (AvSP), in addition to wind velocity and temperature, water vapor is considered one key factor in determining aviation weather, which is a substantial contributor to many general aviation (GA) accidents. The conventional and reliable humidity measuring methods such as radiation reflection or absorption have relatively high cost in addition to highly specialized operating and maintenance characteristics. This paper presents characterizations of inexpensive MEMS and capacitance type humidity sensors for their potential use on aircraft. If installed, these sensors are subjected to ambient environmental conditions as well as to different chemicals and deicing fluids used on aircraft. This paper reports the effect of different deicing fluids and chemicals on these inexpensive humidity sensors.

Composites of Graphene Nanoribbon Stacks and Epoxy for Joule Heating and Deicing of Surfaces.

PubMed

Raji, Abdul-Rahman O; Varadhachary, Tanvi; Nan, Kewang; Wang, Tuo; Lin, Jian; Ji, Yongsung; Genorio, Bostjan; Zhu, Yu; Kittrell, Carter; Tour, James M

2016-02-10

A conductive composite of graphene nanoribbon (GNR) stacks and epoxy is fabricated. The epoxy is filled with the GNR stacks, which serve as a conductive additive. The GNR stacks are on average 30 nm thick, 250 nm wide, and 30 μm long. The GNR-filled epoxy composite exhibits a conductivity >100 S/m at 5 wt % GNR content. This permits application of the GNR-epoxy composite for deicing of surfaces through Joule (voltage-induced) heating generated by the voltage across the composite. A power density of 0.5 W/cm(2) was delivered to remove ∼1 cm-thick (14 g) monolith of ice from a static helicopter rotor blade surface in a -20 °C environment.

Environmentally friendly anti-icing

NASA Technical Reports Server (NTRS)

Zuk, John (Inventor); Haslim, Leonard A. (Inventor); Lockyer, Robert T. (Inventor)

1998-01-01

The present invention describes an aqueous, non-electrolytic, non-toxic, biodegradable, continuous single phase liquid anti-icing or deicing composition for use on the surfaces of, for example, aircraft, airport pavements, roadways, walkways, bridges, entrances, structures, canals, locks, components, vessels, nautical components, railroad switches, and motor vehicles. The anti-icing or deicing composition comprises: (a) water; (b) a non-toxic freezing point depressant selected from the group consisting of monohydric alcohols having from 2 to 6 carbon atoms, polyhydric alcohols having from 3 to 12 carbon atoms, monomethyl or ethyl ethers of polyhydric alcohols having from 3 to 12 atoms or mixtures thereof, wherein the freezing point depressant present is between about 14 to 60 percent by weight; (c) a thickener which is present in between about 0.01 and 10 percent by weight; and (d) optionally a corrosion inhibitor which is present in between about 0.01 and 0.1 percent by weight of the total composition. In one embodiment, the deicing composition further includes (e) a monohydric primary aliphatic unbranched alcohol as a means of forming a thin layer of the composition on the surface of the structure to be given ice protection, and/or as means of forming a homogenized foam with xanthan thickener; which alcohol is selected from the group consisting of alcohols having between 8 to 24 carbon atoms, preferably, 1-dodecanol. Compositions of water, propylene glycol, and/or propanol and xanthan are preferred.

Preventing Ice Before it Forms

NASA Technical Reports Server (NTRS)

2006-01-01

In the late 1990s, a team of engineers at Ames Research Center invented an anti-icing fluid to keep ice from building up on airplane wings. Ice on wings can be a serious safety hazard, especially during takeoff, when a sheet of ice the thickness of a compact disc can reduce lift by 25 percent or more. The typical approach to clearing off the ice is to use a deicing solution once the ice has built up. The fluid created by the Ames team, though, when applied to a dry surface, prevents the ice from even forming a surface bond, which saves deicing time and money, while also preventing excessive use of chemical solvents. If, however, the solution is not applied before ice forms, it also serves as a traditional deicing formula. The formula contains propylene glycol, which has a very low freezing point, and a thickener, which helps the fluid adhere to the surface. Ice gathers on top of the formula, and then it can be wiped off with little effort. This thickening agent, a pseudo-plastic, sprays on as a liquid, like lemonade, gels like a lemon sherbet, turns back to a liquid when wiped, and then gels again into its sherbet consistency when left to solidify. The sherbet-gel stage is especially important when the formula is sprayed onto a vertical or steeped surface, as it clings better than a liquid would.

The Evaluation of Damage Effects on MgO Added Concrete with Slag Cement Exposed to Calcium Chloride Deicing Salt

PubMed Central

Jang, Jae-Kyeong; Kim, Hong-Gi; Kim, Jun-Hyeong

2018-01-01

Concrete systems exposed to deicers are damaged in physical and chemical ways. In mitigating the damage from CaCl2 deicers, the usage of ground slag cement and MgO are investigated. Ordinary Portland cement (OPC) and slag cement are used in different proportions as the binding material, and MgO in doses of 0%, 5%, 7%, and 10% are added to the systems. After 28 days of water-curing, the specimens are immersed in 30% CaCl2 solution by mass for 180 days. Compressive strength test, carbonation test, chloride penetration test, chloride content test, XRD analysis, and SEM-EDAX analysis are conducted to evaluate the damage effects of the deicing solution. Up to 28 days, plain specimens with increasing MgO show a decrease in compressive strength, an increase in carbonation resistance, and a decrease in chloride penetration resistance, whereas the S30- and S50- specimens show a slight increase in compressive strength, an increase in carbonation resistance, and a slight increase in chloride penetration resistance. After 180 days of immersion in deicing solution, specimens with MgO retain their compressive strength longer and show improved durability. Furthermore, the addition of MgO to concrete systems with slag cement induces the formation of magnesium silicate hydrate (M-S-H) phases. PMID:29758008

Improved management of winter operations to limit subsurface contamination with degradable deicing chemicals in cold regions.

PubMed

French, Helen K; van der Zee, Sjoerd E A T M

2014-01-01

This paper gives an overview of management considerations required for better control of deicing chemicals in the unsaturated zone at sites with winter maintenance operations in cold regions. Degradable organic deicing chemicals are the main focus. The importance of the heterogeneity of both the infiltration process, due to frozen ground and snow melt including the contact between the melting snow cover and the soil, and unsaturated flow is emphasised. In this paper, the applicability of geophysical methods for characterising soil heterogeneity is considered, aimed at modelling and monitoring changes in contamination. To deal with heterogeneity, a stochastic modelling framework may be appropriate, emphasizing the more robust spatial and temporal moments. Examples of a combination of different field techniques for measuring subsoil properties and monitoring contaminants and integration through transport modelling are provided by the SoilCAM project and previous work. Commonly, the results of flow and contaminant fate modelling are quite detailed and complex and require post-processing before communication and advising stakeholders. The managers' perspectives with respect to monitoring strategies and challenges still unresolved have been analysed with basis in experience with research collaboration with one of the case study sites, Oslo airport, Gardermoen, Norway. Both scientific challenges of monitoring subsoil contaminants in cold regions and the effective interaction between investigators and management are illustrated.

FIRE_AX_UKMO_C130

Atmospheric Science Data Center

2015-11-25

... FSSP Gust Probe Hot-Wire Hygrometer Platinum Resistance PMS 2D-C Probe PRT-4 Pyranometer Pyrgeometer ... Parameters:  Barometric Altitude Cloud Top Temperature Deiced Temperature Dew/Frost Point Temperature Droplet ...

Highly Conductive Carbon Fiber Reinforced Concrete for Icing Prevention and Curing.

PubMed

Galao, Oscar; Bañón, Luis; Baeza, Francisco Javier; Carmona, Jesús; Garcés, Pedro

2016-04-12

This paper aims to study the feasibility of highly conductive carbon fiber reinforced concrete (CFRC) as a self-heating material for ice formation prevention and curing in pavements. Tests were carried out in lab ambient conditions at different fixed voltages and then introduced in a freezer at -15 °C. The specimens inside the freezer were exposed to different fixed voltages when reaching +5 °C for prevention of icing and when reaching the temperature inside the freezer, i.e. , -15 °C, for curing of icing. Results show that this concrete could act as a heating element in pavements with risk of ice formation, consuming a reasonable amount of energy for both anti-icing (prevention) and deicing (curing), which could turn into an environmentally friendly and cost-effective deicing method.

Transport processes in partially saturate concrete: Testing and liquid properties

NASA Astrophysics Data System (ADS)

Villani, Chiara

The measurement of transport properties of concrete is considered by many to have the potential to serve as a performance criterion that can be related to concrete durability. However, the sensitivity of transport tests to several parameters combined with the low permeability of concrete complicates the testing. Gas permeability and diffusivity test methods are attractive due to the ease of testing, their non-destructive nature and their potential to correlate to in-field carbonation of reinforced concrete structures. This work was aimed at investigating the potential of existing gas transport tests as a way to reliably quantify transport properties in concrete. In this study gas permeability and diffusivity test methods were analyzed comparing their performance in terms of repeatability and variability. The influence of several parameters was investigated such as moisture content, mixture proportions and gas flow. A closer look to the influence of pressure revealed an anomalous trend of permeability with respect to pressure. An alternative calculation is proposed in an effort to move towards the determination of intrinsic material properties that can serve as an input for service life prediction models. The impact of deicing salts exposure was also analyzed with respect to their alteration of the degree of saturation as this may affect gas transport in cementitious materials. Limited information were previously available on liquid properties over a wide range of concentrations. To overcome this limitation, this study quantified surface tension, viscosity in presence of deicing salts in a broad concentration range and at different temperatures. Existing models were applied to predict the change of fluid properties during drying. Vapor desorption isotherms were obtained to investigate the influence of deicing salts presence on the non-linear moisture diffusion coefficient. Semi-empirical models were used to quantify the initiation and the rate of drying using liquid properties and pore structure information as inputs. Concrete exposed to deicing salts resulted to have a reduced gas transport due to the higher degree of saturation (DOS). The higher DOS is believed to contribute to the premature deterioration observed in concrete pavements exposed to deicing salts. Moisture diffusion and moisture profiles in concrete are known to directly relate with the stresses generated during shrinkage and creep mechanisms. The alteration due to the presence of shrinkage reducing admixtures on drying was also investigated in this work. Liquid properties were used to predict the diffusion coefficient in presence of SRA. Moisture profiles obtained using Fick's second law for diffusion were compared to relative humidity profiles measured on concrete slabs. Results confirm that a qualitative prediction of drying in concrete elements is realistic when using this type of approach.

40 CFR 266.20 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... contain. (c) Anti-skid/deicing uses of slags, which are generated from high temperature metals recovery...) Fertilizers that contain recyclable materials are not subject to regulation provided that: (1) They are zinc...

40 CFR 266.20 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-07-01

... contain. (c) Anti-skid/deicing uses of slags, which are generated from high temperature metals recovery...) Fertilizers that contain recyclable materials are not subject to regulation provided that: (1) They are zinc...

Handling Hot Water, With a Payoff

ERIC Educational Resources Information Center

Stewart, Ronald; Mathur, S. P.

1970-01-01

Discusses methods of utilizing waste heat from the increasing number of power stations. Possible uses include agri- and mariculture, centralized urban and industrial heating, and deicing of airports and marine facilities. (AL)

An Investigation of the Icing and Heated-air De-icing Characteristics of the R-2600-13 Induction System

NASA Technical Reports Server (NTRS)

Chapman, Gilbert E.

1946-01-01

A laboratory investigation was made on a Holley 1685-HB carburetor mounted on an R-2600-13 supercharger assembly to determine the icing characteristics and the heated-air de-icing requirements of this portion of the B-25D airplane induction system. Icing has been found to be most prevalent at relatively small throttle openings and, consequently, all runs were made at simulated 60-percent normal rated power condition. Icing characteristics were determined during a series of 15-minute runs over a range of inlet-air conditions. For the de-icing investigation severe impact ice was allowed to form in the induction system and the time required for the recovery of 95 percent of the maximum possible air flow at the original throttle setting was then determined for a range of wet-bulb temperatures. Results of these runs showed that ice on the walls of the carburetor adapter and on the rim of the impeller-shroud portion of the supercharger diffuser plate did not affect engine operation at 60-percent normal rated power. Ice that adversely affected the air flow and the fuel-air ratio was formed only on the central web of the carburetor and then only when the inlet air was saturated or contained free moisture in excess of saturation. No serious ice formations were observed at inlet-air temperatures above 66 0 F or with an inlet-air enthalpy greater than 34 Btu per pound. The maximum temperature at. which any trace of icing could be detected was 1110 F with a relative humidity of approximately 28 percent, The air-flow recovery time for emergency de-icing was 0.3 minute for.an enthalpy of 35 Btu per pound or wet-bulb temperature of 68 0 F. Further increase in enthalpy and wet-bulb temperature above these values resulted in very slight improvement in recovery time. The fuel-air ratio restored by a 5-Minute application of heated air was approximately 7 percent less than the initial value for cold-air conditions.

Installation of stormwater management and treatment demonstration facility.

DOT National Transportation Integrated Search

2013-06-01

Roadway runoff contributes large amounts of suspended solids/sediment, heavy metals, petroleum : hydrocarbons, deicing chemicals, bacteria and other constituents to receiving waterways. The EPA : National Urban Runoff Program (NURP) indicated that le...

Proposed testing of concrete sealers.

DOT National Transportation Integrated Search

2017-07-04

Chlorides, in sufficient concentrations, will cause corrosion of steel reinforcement in bridge decks. Previous studies have shown that de-icing chemicals and practices used by the Kentucky Transportation Cabinet (KYTC) can result in problematic level...

Controlling conductivity of asphalt concrete with graphite.

DOT National Transportation Integrated Search

2014-08-01

Electrically conductive asphalt concrete has a huge potential for various multifunctional applications such as : self-healing, self-sensing, and deicing. In order to utilize the full spectrum of applications of electrically conductive : asphalt compo...

14 CFR 25.929 - Propeller deicing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... intended for use where icing may be expected, there must be a means to prevent or remove hazardous ice accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b) If...

14 CFR 25.929 - Propeller deicing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... intended for use where icing may be expected, there must be a means to prevent or remove hazardous ice accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b) If...

14 CFR 25.929 - Propeller deicing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... intended for use where icing may be expected, there must be a means to prevent or remove hazardous ice accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b) If...

14 CFR 25.929 - Propeller deicing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... intended for use where icing may be expected, there must be a means to prevent or remove hazardous ice accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b) If...

14 CFR 25.929 - Propeller deicing.

Code of Federal Regulations, 2011 CFR

2011-01-01

... intended for use where icing may be expected, there must be a means to prevent or remove hazardous ice accumulation on propellers or on accessories where ice accumulation would jeopardize engine performance. (b) If...

Corrosion inhibitors for concrete bridges.

DOT National Transportation Integrated Search

2004-12-01

Deicing salts and salt-water spray can cause serious corrosion problems for reinforced concrete bridge structures. : These problems can lead to costly and labor-intensive repair and even replacement of the structure. Surface applied : corrosion inhib...

Fixed automated spray technology.

DOT National Transportation Integrated Search

2011-04-19

This research project evaluated the construction and performance of Boschungs Fixed Automated : Spray Technology (FAST) system. The FAST system automatically sprays de-icing material on : the bridge when icing conditions are about to occur. The FA...

Full two-dimensional transient solutions of electrothermal aircraft blade deicing

NASA Technical Reports Server (NTRS)

Masiulaniec, K. C.; Keith, T. G., Jr.; Dewitt, K. J.; Leffel, K. L.

1985-01-01

Two finite difference methods are presented for the analysis of transient, two-dimensional responses of an electrothermal de-icer pad of an aircraft wing or blade with attached variable ice layer thickness. Both models employ a Crank-Nicholson iterative scheme, and use an enthalpy formulation to handle the phase change in the ice layer. The first technique makes use of a 'staircase' approach, fitting the irregular ice boundary with square computational cells. The second technique uses a body fitted coordinate transform, and maps the exact shape of the irregular boundary into a rectangular body, with uniformally square computational cells. The numerical solution takes place in the transformed plane. Initial results accounting for variable ice layer thickness are presented. Details of planned de-icing tests at NASA-Lewis, which will provide empirical verification for the above two methods, are also presented.

LEWICE 2.2 Capabilities and Thermal Validation

NASA Technical Reports Server (NTRS)

Wright, William B.

2002-01-01

A computational model of bleed air anti-icing and electrothermal de-icing have been added to the LEWICE 2.0 software by integrating the capabilities of two previous programs, ANTICE and LEWICE/ Thermal. This combined model has been released as LEWICE version 2.2. Several advancements have also been added to the previous capabilities of each module. This report will present the capabilities of the software package and provide results for both bleed air and electrothermal cases. A comprehensive validation effort has also been performed to compare the predictions to an existing electrothermal database. A quantitative comparison shows that for deicing cases, the average difference is 9.4 F (26%) compared to 3 F for the experimental data while for evaporative cases the average difference is 2 F (32%) compared to an experimental error of 4 F.

A finite element study of the EIDI system. [Electro-Impulse De-Icing System

NASA Technical Reports Server (NTRS)

Khatkhate, A. A.; Scavuzzo, R. J.; Chu, M. L.

1988-01-01

This paper presents a method for modeling the structural dynamics of an Electro-Impulse De-Icing System, using finite element analyses procedures. A guideline for building a representative finite element model is discussed. Modeling was done initially using four noded cubic elements, four noded isoparametric plate elements and eight noded isoparametric shell elements. Due to the size of the problem and due to the underestimation of shear stress results when compared to previous analytical work an approximate model was created to predict possible areas of shedding of ice. There appears to be good agreement with the test data provided by The Boeing Commercial Airplane Company. Thus these initial results of this method were found to be encouraging. Additional analytical work and comparison with experiment is needed in order to completely evaluate this approach.

Long-term ferrocyanide application via deicing salts promotes the establishment of Actinomycetales assimilating ferrocyanide-derived carbon in soil.

PubMed

Gschwendtner, Silvia; Mansfeldt, Tim; Kublik, Susanne; Touliari, Evangelia; Buegger, Franz; Schloter, Michael

2016-07-01

Cyanides are highly toxic and produced by various microorganisms as defence strategy or to increase their competitiveness. As degradation is the most efficient way of detoxification, some microbes developed the capability to use cyanides as carbon and nitrogen source. However, it is not clear if this potential also helps to lower cyanide concentrations in roadside soils where deicing salt application leads to significant inputs of ferrocyanide. The question remains if biodegradation in soils can occur without previous photolysis. By conducting a microcosm experiment using soils with/without pre-exposition to road salts spiked with (13) C-labelled ferrocyanide, we were able to confirm biodegradation and in parallel to identify bacteria using ferrocyanide as C source via DNA stable isotope probing (DNA-SIP), TRFLP fingerprinting and pyrosequencing. Bacteria assimilating (13) C were highly similar in the pre-exposed soils, belonging mostly to Actinomycetales (Kineosporia, Mycobacterium, Micromonosporaceae). In the soil without pre-exposition, bacteria belonging to Acidobacteria (Gp3, Gp4, Gp6), Gemmatimonadetes (Gemmatimonas) and Gammaproteobacteria (Thermomonas, Xanthomonadaceae) used ferrocyanide as C source but not the present Actinomycetales. This indicated that (i) various bacteria are able to assimilate ferrocyanide-derived C and (ii) long-term exposition to ferrocyanide applied with deicing salts leads to Actinomycetales outcompeting other microorganisms for the use of ferrocyanide as C source. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

New Fluid Prevents Railway Ice

NASA Technical Reports Server (NTRS)

2001-01-01

Through a licensing agreement between NASA's Ames Research Center and Midwest Industrial Supply, Inc. (MIS), two MIS products have been enhanced with NASA's anti-icing fluid technology. MIS offers the new fluid in two commercial products, the Zero Gravity(TM) Third Rail Anti-Icer/Deicer and the Ice Free Switch(R). Using NASA's fluid technology, these products form a protective-coating barrier that prevents the buildup of ice and snow. Applying the fluid to the railway components prior to ice or snowstorm works as an anti-icing fluid, remaining in place to melt precipitation as it hits the surface. It also functions as a deicing fluid. If applied to an already frozen switch or rail, it will quickly melt the ice, free the frozen parts, and then remain in place to prevent refreezing. Additional benefits include the ability to cling to vertical rail surfaces and resist the effects of rain and wind. With the Ice Free Switch, it takes only five minutes to treat the switch by spraying, brushing, or pouring on the product. Ice Free Switch requires as little as one gallon per switch whereas other deicing fluids require five to ten gallons of liquid to effectively melt ice. Zero Gravity serves the same anti-icing/deicing purposes but applies fluid to the third rail through a system that is easily installed onto mass transit cars. A tank of fluid and a dispensing system are placed underneath the train car and the fluid is applied as the train runs its route.

Optimizing a Test Method to Evaluate Resistance of Pervious Concrete to Cycles of Freezing and Thawing in the Presence of Different Deicing Salts

PubMed Central

Tsang, Chehong; Shehata, Medhat H.; Lotfy, Abdurrahmaan

2016-01-01

The lack of a standard test method for evaluating the resistance of pervious concrete to cycles of freezing and thawing in the presence of deicing salts is the motive behind this study. Different sample size and geometry, cycle duration, and level of submersion in brine solutions were investigated to achieve an optimized test method. The optimized test method was able to produce different levels of damage when different types of deicing salts were used. The optimized duration of one cycle was found to be 24 h with twelve hours of freezing at −18 °C and twelve hours of thawing at +21 °C, with the bottom 10 mm of the sample submerged in the brine solution. Cylinder samples with a diameter of 100 mm and height of 150 mm were used and found to produce similar results to 150 mm-cubes. Based on the obtained results a mass loss of 3%–5% is proposed as a failure criterion of cylindrical samples. For the materials and within the cycles of freezing/thawing investigated here, the deicers that caused the most damage were NaCl, CaCl2 and urea, followed by MgCl2, potassium acetate, sodium acetate and calcium-magnesium acetate. More testing is needed to validate the effects of different deicers under long term exposures and different temperature ranges. PMID:28773998

Evaluation of deicer applications on open graded pavements : final report.

DOT National Transportation Integrated Search

2006-04-01

The Oregon Department of Transportation (ODOT) winter maintenance practices include plowing, sanding, and applying winter anti-icing/deicing liquids. These activities are performed on dense-graded as well as open-graded pavements. During the winters ...

Bridge deck service life prediction and costs.

DOT National Transportation Integrated Search

2007-01-01

The service life of Virginia's concrete bridge decks is generally controlled by chloride-induced corrosion of the reinforcing steel as a result of the application of winter maintenance deicing salts. A chloride corrosion model accounting for the vari...

Spiral passive electromagnetic sensor (SPES) for smart sensing and de-icing

NASA Astrophysics Data System (ADS)

Iervolino, Onorio; Meo, Michele

2015-04-01

The objective of this work was to develop a wireless Spiral Passive Electromagnetic Sensor (SPES) to monitor the complex permittivity of a surrounding medium. The sensor is a self-resonating planar pattern of electrically conductive material. Investigation were conducted to demonstrate the capability of the SPES to monitor humidity and temperature gradients, and acting as an ice protection tool. An oscillating signal is used to interrogate remotely the sensor with a single loop antenna or wiring it directly to a spectrum analyser and monitoring the backscattering signal. The excited sensor responds with its own resonant frequency, amplitude and bandwidth that can be correlated to physical quantities to be monitored. Our studies showed the capability of the sensor to monitor temperature and humidity changes in composite materials and uniformly produce induction heating when the conductive path is activated by an external electric power supply that can be used for deicing of aircraft structures.

Theoretical analysis of the electrical aspects of the basic electro-impulse problem in aircraft de-icing applications

NASA Technical Reports Server (NTRS)

Henderson, Robert A.; Schrag, Robert L.

1987-01-01

A method of modelling a system consisting of a cylindrical coil with its axis perpendicular to a metal plate of finite thickness, and a simple electrical circuit for producing a transient current in the coil, is discussed in the context of using such a system for de-icing aircraft surfaces. A transmission line model of the coil and metal plate is developed as the heart of the system model. It is shown that this transmission model is central to calculation of the coil impedance, the coil current, the magnetic fields established on the surfaces of the metal plate, and the resultant total force between the coil and the plate. FORTRAN algorithms were developed for numerical calculation of each of these quantities, and the algorithms were applied to an experimental prototype system in which these quantities had been measured. Good agreement is seen to exist between the predicted and measured results.

Validation of NASA Thermal Ice Protection Computer Codes. Part 1; Program Overview

NASA Technical Reports Server (NTRS)

Miller, Dean; Bond, Thomas; Sheldon, David; Wright, William; Langhals, Tammy; Al-Khalil, Kamel; Broughton, Howard

1996-01-01

The Icing Technology Branch at NASA Lewis has been involved in an effort to validate two thermal ice protection codes developed at the NASA Lewis Research Center. LEWICE/Thermal (electrothermal deicing & anti-icing), and ANTICE (hot-gas & electrothermal anti-icing). The Thermal Code Validation effort was designated as a priority during a 1994 'peer review' of the NASA Lewis Icing program, and was implemented as a cooperative effort with industry. During April 1996, the first of a series of experimental validation tests was conducted in the NASA Lewis Icing Research Tunnel(IRT). The purpose of the April 96 test was to validate the electrothermal predictive capabilities of both LEWICE/Thermal, and ANTICE. A heavily instrumented test article was designed and fabricated for this test, with the capability of simulating electrothermal de-icing and anti-icing modes of operation. Thermal measurements were then obtained over a range of test conditions, for comparison with analytical predictions. This paper will present an overview of the test, including a detailed description of: (1) the validation process; (2) test article design; (3) test matrix development; and (4) test procedures. Selected experimental results will be presented for de-icing and anti-icing modes of operation. Finally, the status of the validation effort at this point will be summarized. Detailed comparisons between analytical predictions and experimental results are contained in the following two papers: 'Validation of NASA Thermal Ice Protection Computer Codes: Part 2- The Validation of LEWICE/Thermal' and 'Validation of NASA Thermal Ice Protection Computer Codes: Part 3-The Validation of ANTICE'

Phased array ultrasonic steel corrosion mapping for bridges and ancillary structures.

DOT National Transportation Integrated Search

2017-08-01

Steel corrosion on bridges and ancillary structures due to environmental effects and deicing chemicals is a serious problem for Minnesota's infrastructure. The ability to detect, locate, and measure corrosion is an important aspect of structure inspe...

Laboratory performance of pervious concrete subjected to deicing salts and freeze-thaw.

DOT National Transportation Integrated Search

2015-06-01

Significant research and development have occurred for pervious concrete, but its acceptance in : cold climates is still limited. Vulnerability to freeze-thaw and salt exposure has led to uncertainty : about its long-term performance. Additionally, t...

Effect of salt additives on concrete degradation (Phase II). Executive summary

DOT National Transportation Integrated Search

1995-02-01

This research builds on a previous investigation, which found that corrosion-inhibitor-added deicing salts caused degradation of concrete by both anions and cations. The latest research phase looked at methods to detect the chemical reactions between...

Procedures for the evaluation of sheet membrane waterproofing

DOT National Transportation Integrated Search

1999-08-01

Sheet membrane waterproofing has been used to protect bridge decks against water and deicing salts by transportation agencies in New England for more than two decades. Though such membranes have proven useful at extending the useful life of bridge de...

Field Usage of Alternative Deicers for Snow and Ice Control : Transportation Research Synthesis.

DOT National Transportation Integrated Search

2017-09-01

This Transportation Research Synthesis (TRS) summarizes non-chloride based deicers available on the market at this time, including acetate, formate, glycol, and succinate based deicing products. This report explores their feasibility for use as alter...

The Advanced Transportation Weather Information System (ATWIS)

DOT National Transportation Integrated Search

2000-01-01

Understanding and interpreting weather information can be critical to the success of any winter snow and ice removal operation. Knowing when, where and what type of deicing material to use for a particular winter weather event can be a challenge to e...

Experimental study on an electrical deicing technology utilizing carbon fiber tape.

DOT National Transportation Integrated Search

2012-11-01

In cold regions, snow and ice cause serious safety problems to transportation systems. South central Alaska, particularly Anchorage, is susceptible to a number of icing : events due to frequent freeze/thaw cycles in the winter season. Traditionally, ...

Research notes : thin polymer overlays on bridge decks.

DOT National Transportation Integrated Search

2007-11-01

Winters in Oregon are hard on our bridges. Vehicles with studded tires gouge the pavement and abrade the deck surface. This abrasion often leads to reduced skid resistance. As the bridge deck ages, cracks often develop. Deicing chemicals used in wint...

Durability of saw-cut joints in plain cement concrete pavements.

DOT National Transportation Integrated Search

2011-01-01

The objective of this project was to evaluate factors influencing the durability of the joints in portland cement concrete : pavement in the state of Indiana. Specifically this work evaluated the absorption of water, the absorption of deicing solutio...

Total liquid routes and anti-icing liquids.

DOT National Transportation Integrated Search

2013-10-01

INDOT has successfully used salt brine in antiicing efforts as a way to deliver preventative treatment before an event (e.g. bridge deck : frost) occurs. In 2011 INDOT wanted to investigate the use of salt brine in deicing operations. This stud...

Salt Brine Blending to Optimize Deicing and Anti-Icing Performance and Cost Effectiveness : Phase III

DOT National Transportation Integrated Search

2017-11-01

An evaluation of deicers and anti-icers and plowing, in parallel conditions on actual pavements to assess intuitions based on observations and anecdotal evidence. - Anti-icer persistence - Deicer effectiveness - Plow effectiveness - Pavement study of...

Prototype development of a piezo-heating array for deicing application on bridges : final report.

DOT National Transportation Integrated Search

2017-01-01

A novel piezoelectric transducer was designed and fabricated to demonstrate energy harvesting from traffic-induced loading on pavement. The piezoelectric transducer is based on the cymbal transducer design used for underwater acoustic and sonar...

Fate of ethylene glycol in the environment : final report.

DOT National Transportation Integrated Search

1990-01-01

The Louisiana Department of Transportation and Development uses ethylene glycol (EG) as a deicing agent on bridges. This study was undertaken to assess the impact of EG on workers and the environment after spraying. The objectives of the project were...

Protection of Reinforcement with Corrosion Inhibitors, Phase II

DOT National Transportation Integrated Search

2000-12-01

Costs due to corrosion of reinforcement in concrete caused by deicing salts have been estimated at up to $1 billion per year in the U.S. alone. For most situations, corrosion-inhibiting admixtures offer significant advantages over other protection me...

Investigation of techniques for accelerating the construction of bridge deck overlays : tech transfer summary.

DOT National Transportation Integrated Search

2016-04-01

Todays environment is increasingly hostile to bridge decks with exposure : to deicing salts and environmental factors such as large temperature swings : and polluting chemicals. Being subjected to the most severe loading of all the : bridge compon...

Maintenance Decision Support System, Phase III

DOT National Transportation Integrated Search

2017-09-01

The main goal of the project was to address barriers that limit NDOTs ability to implement MDSS and MMS systems. The four project tasks included: Task 1: Develop system for tracking sand and/or deicing material usage: A system that tracks where and w...

Optimal usage of de-icing chemicals when scraping ice.

DOT National Transportation Integrated Search

2003-11-01

One of the challenges that faces the winter maintainer is how much chemical to : apply to the road under given conditions. Insufficient chemical can lead to the road : surface becoming slick, and the road thus becoming unsafe. In all likelihood, addi...

Rapid replacement of bridge deck expansion joints study - phase I.

DOT National Transportation Integrated Search

2014-12-01

Bridge deck expansion joints are used to allow for movement of the bridge deck due to thermal expansion, dynamics loading, and : other factors. More recently, expansion joints have also been utilized to prevent the passage of winter de-icing chemical...

Impacts of using salt and salt brine for roadway deicing.

DOT National Transportation Integrated Search

2014-06-01

Idaho Transportation Department (ITD) uses a variety of methods to help ensure safe travel on the state highway system : following winter storm events. These methods include plowing, use of sand to improve traction, and use of salt and chemical : com...

Seismic evaluation and retrofit of deteriorated concrete bridge components.

DOT National Transportation Integrated Search

2013-06-01

Corrosion of steel bars in reinforced concrete structures is a major durability problem for bridges constructed in the New York State : (NYS). The heavy use of deicing salt compounds this problem. Corrosion of steel bars results in loss of steel cros...

Improving the freight transportation roadway system during snow events : a performance evaluation of deicing chemicals.

DOT National Transportation Integrated Search

2012-05-01

The ability of state DOTs to adequately clear roadways during winter weather conditions is critical for a safe and effective : freight transportation system. Variables affecting winter maintenance operations include the type of precipitation, air and...

Surface resistivity as an alternative for rapid chloride permeability test of hardened concrete.

DOT National Transportation Integrated Search

2015-03-01

Kansas experiences harsh winters that require frequent use of de-icing salts, making it critical to the long-term : durability of concrete structures that the permeability is kept under control. Under current KDOT specification, the : Rapid Chloride ...

Studies of the environmental fate and effect of aircraft deicing fluids: Detection of 5-methyl-1H-benzotriazole in the fathead minnow (Pimephales promelas)

USGS Publications Warehouse

Cancilla, Devon A.; Baird, J.C.; Geis, S.W.; Corsi, Steven R.

2003-01-01

This paper presents the results of a number of field and laboratory studies to evaluate the environmental impact of aircraft deicing and anti-icing fluids (ADAFs) on aquatic systems. Both 5-methyl-1H-benzotriazole (5-MeBt) and 4-methyl-1H-benzotriazole (4-MeBt), known additives to ADAFs, were found in whole-tissue extracts from minnows placed downstream of an effluent outfall that receives ADAF contaminated runoff from General Mitchell International Airport (Milwaukee, WI, USA). Neither of these compounds was detected in tissues from minnows placed upstream from the airport. A toxicity assessment of water collected during the minnow exposure studies utilizing Hyalella azteca, Pimephales promelas, and Ceriodaphnia dubia showed greater toxicity in a secondary airport outfall containing ADAFs when compared to upstream non-ADAF-contaminated samples. In two 28-d static renewal tests using 5-MeBt laboratory-fortified waters, 5-MeBt was detected in whole-tissue extracts of minnows at all concentrations tested. In studies using laboratory water fortified with 5-MeBt, the median lethal concentration (LC50) of 5-MeBt for P. promelas was found to be 22.0 mg/L. The LC50 for C. dubia to 5-MeBt laboratory-fortified water was found to be 81.3 mg/L. The 25% inhibition concentration (IC25) of 5-MeBt for the green alga Selenastrum capricornutum was 23.2 mg/L, and the average median effective concentration (EC50) for Microtox was 4.25 mg/L. The results of these field and lab studies indicate that additives, other than glycols, used in aircraft deicing fluids can be found in aquatic systems and may be of greater risk than previously believed.

Studies of the environmental fate and effect of aircraft deicing fluids: detection of 5-methyl-1H-benzotriazole in the fathead minnow (Pimephales promelas).

PubMed

Cancilla, Devon A; Baird, J Christopher; Geis, Steven W; Corsi, Steven R

2003-01-01

This paper presents the results of a number of field and laboratory studies to evaluate the environmental impact of aircraft deicing and anti-icing fluids (ADAFs) on aquatic systems. Both 5-methyl-1H-benzotriazole (5-MeBt) and 4-methyl-1H-benzotriazole (4-MeBt), known additives to ADAFs, were found in whole-tissue extracts from minnows placed downstream of an effluent outfall that receives ADAF contaminated runoff from General Mitchell International Airport (Milwaukee, WI, USA). Neither of these compounds was detected in tissues from minnows placed upstream from the airport. A toxicity assessment of water collected during the minnow exposure studies utilizing Hyalella azteca, Pimephales promelas, and Ceriodaphnia dubia showed greater toxicity in a secondary airport outfall containing ADAFs when compared to upstream non-ADAF-contaminated samples. In two 28-d static renewal tests using 5-MeBt laboratory-fortified waters, 5-MeBt was detected in whole-tissue extracts of minnows at all concentrations tested. In studies using laboratory water fortified with 5-MeBt, the median lethal concentration (LC50) of 5-MeBt for P. promelas was found to be 22.0 mg/L. The LC50 for C. dubia to 5-MeBt laboratory-fortified water was found to be 81.3 mg/L. The 25% inhibition concentration (IC25) of 5-MeBt for the green alga Selenastrum capricornutum was 23.2 mg/L, and the average median effective concentration (EC50) for Microtox was 4.25 mg/L. The results of these field and lab studies indicate that additives, other than glycols, used in aircraft deicing fluids can be found in aquatic systems and may be of greater risk than previously believed.

The effect of in-service aerospace contaminants on X-band dielectric properties of a bismaleimide/quartz composite

NASA Astrophysics Data System (ADS)

Rodriguez, Luis A.; García, Carla; Grace, Landon R.

2015-05-01

The impact of three common aerospace in-service liquid contaminants on the X-band dielectric properties of a polymer composite radar protecting structure (radome) is investigated and quantified. The dielectric properties of the composite laminate are critical to radar transparency, and thus performance, of the radome structure. Further, polymer composites are highly susceptible to absorption of liquids. As such, the effect of common aerospace contaminants on the dielectric properties of composite laminates is crucial. Measurement of relative permittivity and loss tangent via a split-post dielectric resonant technique at 10 GHz is used to determine the effect of water, deicing fluid, and propylene glycol absorption in a three-ply quartz-reinforced bismaleimide laminate. Additionally, fluid uptake kinetics are investigated as a function of liquid type. An approximately linear relationship between fluid content and relative permittivity is observed for all three contaminant types. A 1% increase in contaminant content by weight results in a 7.8%, 4.5%, and 2.5% increase in relative permittivity of the material due to water, deicing fluid, and propylene glycol, respectively. A more significant impact is seen in material loss tangent, where a 1% increase in contaminant content by weight is responsible for a 378.5%, 593.0%, and 441.5% increase in loss tangent due to the aforementioned fluids, respectively. A fluid uptake weight content of 1.31%, 3.41%, and 4.28% is achieved for water, deicing fluid, and propylene glycol respectively, at approximately 1300 hours exposure. Based on the reported observations, the dielectric property degradation of composite laminates due to these commonly used fluids is of significant concern for in-service aircraft radar systems routinely exposed to these contaminants.

Long-term leaching from recycled concrete aggregates applied as sub-base material in road construction.

PubMed

Engelsen, Christian J; van der Sloot, Hans A; Petkovic, Gordana

2017-06-01

In the present study, the metal leaching from recycled concrete aggregates (RCA) used in road sub-base is presented after >10years of exposure. The released levels of inorganic constituents, the effect of small variation of pH and the use of de-icing salt during winter season were studied. In addition, speciation modelling for the major elements has been provided. The pH varied from 7.5 to 8.5 for the sub-base constructed with RCA whereas the pH of around 8 was obtained for the test section not affected by the traffic and de-icing salts. Despite a small variation in pH, the leachability of Al, Ca and Mg was found to be strongly dependent on pH and fair agreement between the measured and predicted concentrations was obtained. The speciation modelling indicated that gibbsite, calcite and magnesite controlled the solubility of Al, Ca and Mg, respectively, which was in agreement with the expected carbonation products. Due to the larger pH fluctuations in the test sections exposed to the road traffic, increased concentrations were observed for the oxyanions. The same effect was not seen for the trace metal cations Cd, Cu, Ni, Pb and Zn. The distinct pH dependent leaching profile (solubility maximum in the mildly basic pH region) for vanadium could be seen after 10years of exposure. The simplified risk assessment showed that the released quantities did not exceed the chosen acceptance criteria for groundwater and fresh water. The results obtained for the test section not influenced by road dust and de-icing salts, complied with these criteria even without considering any dilution effects caused by the mixing of pore water with groundwater. Copyright © 2017 Elsevier B.V. All rights reserved.

Strategies to Increase the service life of concrete bridge decks : final report.

DOT National Transportation Integrated Search

2017-03-01

Corrosion of the steel in reinforced concrete bridge decks is a critical issue for structures that are exposed to chloride containing de-icing chemicals or marine salts. Oregon Department of Transportation (ODOT) has a large number of bridges that ar...

Study of the De-Icing Properties of the ASDE-3 Rotodome

DOT National Transportation Integrated Search

1982-04-01

A study was conducted of the thermal characteristics of the ASDE-3 system's rotating radome (rotodome), a spheri-toroidal thin wall structure, approximately 18 feet in diameter and 6 feet in height. The purpose of the study was to determine the therm...

An alternative potentiometric method for determining chloride content in concrete samples from reinforced-concrete bridges.

DOT National Transportation Integrated Search

2002-01-01

Analysis of chloride contents in ground concrete samples collected from reinforced concrete bridges and other structures exposed to deicing salts or seawater has become an important part of the inspection for such structures. Such an analysis provide...

The protection effectiveness of waterproof membrane systems on bridge decks in Louisiana : final report.

DOT National Transportation Integrated Search

1978-12-01

The effects of de-icing salts on concrete and reinforcing steel is well documented, and efficient methods of protection from the penetrating chloride ions have long been sought. Concrete bridge decks need the protection, and waterproofing the concret...

Non-destructive and destructive investigation of aged-in-the field carbon FRP-wrapped columns.

DOT National Transportation Integrated Search

2011-06-01

The common practice of applying deicing salts on highway bridges increases the potential of reinforcing steel in these structures to experience extensive corrosion in the decks as well as the substructure. A new rehabilitation method which is believe...

Iowa DOT weather information system to support winter maintenance operations

DOT National Transportation Integrated Search

2000-01-01

Understanding and interpreting weather information can be critical to the success of any winter snow and ice removal operation. Knowing when, where and what type of deicing material to use for a particular winter weather event can be a challenge to e...

Surface resistivity as an alternative for rapid chloride permeability test of hardened concrete : [technical summary].

DOT National Transportation Integrated Search

2015-03-01

Kansas experiences harsh winters that require frequent use of de-icing salts, making it : critical to the long-term durability of concrete structures that the permeability is kept : under control. Under current KDOT specification, the Rapid Chloride ...

Nanoscale deicing by molecular dynamics simulation.

PubMed

Xiao, Senbo; He, Jianying; Zhang, Zhiliang

2016-08-14

Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice adhesion strength by an aqueous water layer, and provide atomistic details that support previous experimental studies. Our results contribute quantitative comparison of nanoscale adhesion strength of ice on hydrophobic and hydrophilic surfaces, and supply for the first time theoretical references for understanding the mechanics at the atomistic origins of macroscale ice adhesion.

Assessment of Lightning Transients on a De-Iced Rotor Blade with Predictive Tools and Coaxial Return Measurements

NASA Astrophysics Data System (ADS)

Guillet, S.; Gosmain, A.; Ducoux, W.; Ponçon, M.; Fontaine, G.; Desseix, P.; Perraud, P.

2012-05-01

The increasing use of composite materials in aircrafts primary structures has led to different problematics in the field of safety of flight in lightning conditions. The consequences of this technological mutation, which occurs in a parallel context of extension of electrified critical functions, are addressed by aircraft manufacturers through the enhancement of their available assessment means of lightning transient. On the one hand, simulation tools, provided an accurate description of aircraft design, are today valuable assessment tools, in both predictive and operative terms. On the other hand, in-house test means allow confirmation and consolidation of design office hardening solutions. The combined use of predictive simulation tools and in- house test means offers an efficient and reliable support for all aircraft developments in their various life-time stages. The present paper provides PREFACE research project results that illustrate the above introduced strategy on the de-icing system of the NH90 composite main rotor blade.

Development of a mechanical rocker test procedure for ice melting capacity evaluation.

DOT National Transportation Integrated Search

2014-06-01

During Phase 2 of the NDOR deicing chemicals performance evaluation project (No. SPR-P1(10) P328), a : simple and economical test using a martini shaker to evaluate ice melting capacity of liquid deicers showed : good potential to become a standardiz...

Numerical Simulation of Internal Heat Transfer Phenomena Occurring During De-Icing of Aircraft Components

NASA Technical Reports Server (NTRS)

DeWitt, Keneth J.

1996-01-01

An experimental study to determine the convective heat transfer coefficient from castings made from ice-roughened plates is reported. A corresponding topic, 'Measurements of the Convective Heat Transfer Coefficient from Ice Roughened Surfaces in Parallel and Accelerated Flows,' is presented.

Validation of NASA Thermal Ice Protection Computer Codes Part 2 - LEWICE/Thermal

DOT National Transportation Integrated Search

1996-01-01

The Icing Technology Branch at NASA Lewis has been involved in an effort to validate two thermal ice protection codes developed at the NASA Lewis Research Center: LEWICE/Thermal 1 (electrothermal de-icing and anti-icing), and ANTICE 2 (hot gas and el...

Hazard identification for human and ecological effects of sodium chloride road salt.

DOT National Transportation Integrated Search

2007-07-01

The New Hampshire Department of Environmental Services (DES) requested an evaluation of : the human and ecological risks associated with the application of sodium chloride (NaCl) road : salt to roadways. NaCl is the major de-icing agent used in NH to...

75 FR 65551 - Notice of Passenger Facility Charge (PFC) Approvals and Disapprovals

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-25

... at a $3.00 PFC Level: New terminal development schematic preliminary engineering study and design... for Collection and Use: Air carrier apron. Pavement condition inventory. New terminal building... construction. De-icing treatment plant. Domestic water service. CTX design and installation. Landside planning...

An evaluation of the use of liquid calcium chloride to improve deicing and snow removal.

DOT National Transportation Integrated Search

1978-01-01

The Iowa method of spraying liquid calcium chloride onto sodium chloride applied in snow and ice removal operations was evaluated On four sections of highway in the Staunton District. From the relatively sparse data accumulated over three winters, it...

Effects of calcium magnesium acetate, a road deicer, on the lentic environment in interior Alaska, interim report

DOT National Transportation Integrated Search

1985-03-01

The application of chloride deicing salts to roadways has increased dramatically in recent years due to public demand for safer winter driving conditions. Unfortunately, these salts create adverse effects such as corrosion of vehicles and bridge stru...

Assessment of soil and wash water quality beneath salt-spreader racks.

DOT National Transportation Integrated Search

2008-01-01

The Virginia Department of Transportation's (VDOT) winter maintenance program hinges primarily on the use of granular NaCl for deicing. On average, VDOT applies more than 300,000 tons of NaCl each winter season. The majority of this salt is spread by...

Performance of thin bonded epoxy overlays on asphalt and concrete bridge deck surfaces.

DOT National Transportation Integrated Search

2014-06-01

This study is the evaluation of two thin bonded epoxy overlays: SafeLane (marketed by Cargill), and Flexogrid : (developed by PolyCarb). SafeLane is advertised as an anti-skid/anti-icing overlay that stores deicing chemicals for : release during wint...

Effects of calcium magnesium acetate on small lentic environments in interior Alaska

DOT National Transportation Integrated Search

1986-08-01

The use of deicing compounds on winter roads has become an accepted practice for snow and ice removal in northern areas. The most commonly employed compounds have been the chloride salts sodium chloride (NaCl) and calcium chloride (CaCl(2)). The appl...

Potential for Natural Brine for Anti-Icing and De-Icing

DOT National Transportation Integrated Search

2012-09-01

This project focused on the feasibility of the use of natural brine for anti-icing and pre-wetting in Onondaga County, : Syracuse, New York. A thorough literature review was conducted on the use of brine as an anti-icing and pre-wetting : agent both ...

Environmental Effects and Treatment Alternatives for Urea Runoff from Airfield De-Icing Operations.

DTIC Science & Technology

1980-08-01

fish and an insect used in aquatic bioassays. Generally, urea concentrations have to exceed several thousand milligrams per liter before significant... acuatic life than ammonia, the possibility exists that this process could degrade rather than purify the water, and is therefore not recom- mended for

77 FR 29167 - Effluent Limitations Guidelines and New Source Performance Standards for the Airport Deicing...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-16

... reductions in dissolved oxygen, fish kills, reduced organism abundance and species diversity, contamination... 13045: Protection of Children From Environmental Health and Safety Risks H. EO 13211: Energy Effects I... water in residential areas and parkland, and other effects. Today, EPA is promulgating effluent...

78 FR 57208 - Notice of Passenger Facility Charge (PFC) Approvals and Disapprovals

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-17

... LEVEL: End of runway deicing program--phase 1, runway 34R. Taxiway S pavement reconstruction. Replace carousel 9 and oversized bag belt TU3. Terminal redevelopment program--design and associated technical... APPROVED FOR COLLECTION AND USE: PFC program administration. Design taxiways A, L and B. BRIEF DESCRIPTION...

Aeronautical Engineering: A Continuing Bibliography with Indexes (Supplement 216)

DTIC Science & Technology

1987-08-01

HELO COMPUTER-AIDED PROCESSES FOR THE GROUND TESTING PATRICK J. DONOGHUE, PREBEN JENSEN, and ROBERT M. OF AVIATION EQUIPMENT [ SISTEMA ZADACH PROEKTIRO...need for an increased awareness of the various companion document to NASA TM-83186. A User’s Guide to the types of deicing fluids and facilities

Potential for natural brine for anti-icing and de-icing.

DOT National Transportation Integrated Search

2012-09-01

This project focused on the feasibility of the use of natural brine for anti-icing and pre-wetting in Onondaga County, Syracuse, New York. A thorough literature review was conducted on the use of brine as an anti-icing and pre-wetting agent both in t...

14 CFR 29.1189 - Shutoff means.

Code of Federal Regulations, 2010 CFR

2010-01-01

... engine; (2) For oil systems for turbine engine installations in which all components of the system, including oil tanks, are fireproof or located in areas not subject to engine fire conditions; or (3) For...) There must be means to shut off or otherwise prevent hazardous quantities of fuel, oil, de-icing fluid...

Evaluation of Municipal Wastewater Treatment Plant Activated Sludge for Biodegradation of Propylene Glycol as an Aircraft Deicing Fluid

DTIC Science & Technology

2012-03-01

Propylene Glycol Deicer Biodegredation Kinetics: Complete-Mix Stirred Tank Reactors , Filter, and Fluidized Bed . Journal of Environmental...scale sequencing batch reactor containing municipal waste water treatment facility activated sludge (AS) performing simultaneous organic carbon...Sequencing Batch Reactor Operation ..................................................................... 13 PG extraction from AS

Development of durable green concrete exposed to deicing chemicals via synergistic use of locally available recycled materials and multi-scale modifiers

DOT National Transportation Integrated Search

2018-02-02

From the economic and social perspectives, the use of waste materials would not be attractive until their costs and quality can satisfy the construction requirements. In this study, a pure fly ash paste (PFAP) was developed in place of ordinary Portl...

Ice-Free Arctic Ocean?

ERIC Educational Resources Information Center

Science Teacher, 2005

2005-01-01

The current warming trends in the Arctic may shove the Arctic system into a seasonally ice-free state not seen for more than one million years, according to a new report. The melting is accelerating, and researchers were unable to identify any natural processes that might slow the deicing of the Arctic. "What really makes the Arctic different…

Three Permeable Pavements Performances for Priority Metal Pollutants and Metals Associated with Deicing Chemicals from Edison Parking Lot, NJ

EPA Science Inventory

The U.S. Environmental Protection Agency constructed a 4000-m2 parking lot in Edison, New Jersey in 2009. The parking lot is surfaced with three permeable pavements [permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA)]. Samples of each p...

Fate and toxicity of aircraft deicing fluid additives through anaerobic digestion.

PubMed

Gruden, C L; Dow, S M; Hernandez, M T

2001-01-01

Benzotriazole derivatives are widely used corrosion inhibitors and their fate during wastewater treatment processes is unknown. The purpose of this research was to study the toxic effects and fate of the two commercially significant benzotriazole isomers used in aircraft deicing fluids (4-, and 5-, methylbenzotriazole [MeBT]) during anaerobic digestion. Experiments were executed in microcosms using mesophilic anaerobic biomass co-digesting wastewater sludge and propylene glycol. Sorption of MeBT to digesting solids could be approximated with a Freundlich model, and no anaerobic breakdown of either MeBT isomer was detected. Digesters fed more than 300 mg/L MeBT responded with a significant decrease in methanogenic microbial activity and volatile solids production and a concomitant increase in accumulation of volatile fatty acids. Direct microscopic measurements using fluorescent phylogenetic probes applied to digesting biomass revealed that members of both Archaea and Bacteria domains were sensitive to MeBT. Granular activated carbon (GAC) (volatile solids: GAC = 10%) reduced the apparent toxic effects of MeBT; GAC addition nearly restored the baseline activity of digesters fed MeBT (500 to 1000 mg/L).

Kinetics of microbial degradation of deicing chemicals in percolated porous media - the modeling perspective

NASA Astrophysics Data System (ADS)

Wehrer, Markus; Lissner, Heidi; Totsche, Kai

2013-04-01

A quantitative knowledge of the fate of deicing chemicals in the subsurface can be provided by analysis of laboratory and field experiments with numerical simulation models. In the present study, experimental data of microbial degradation of the deicing chemical propylene glycol (PG) under flow conditions in soil columns and field lysimeters were simulated to analyze the process conditions of degradation and to obtain the according parameters. Results from the column experiment were evaluated applying different scenarios of an advection-dispersion model using HYDRUS-1D. To reconstruct the data, different competing degradation models were included, i.e., zero order, first order and inclusion of a growing and decaying biomass. The general breakthrough behavior of propylene glycol in soil columns can be simulated well using a coupled model of solute transport and degradation with growth and decay of biomass. The susceptibility of the model to non-unique solutions was investigated using systematical forward and inverse simulations. We found that the model tends to equifinal solutions under certain conditions. Complex experimental boundary conditions can help to avoid this. Under field conditions, the situation is far more complex than in the laboratory. Studying the fate of PG with undisturbed lysimeters we found that aerobic and anaerobic degradation occurs simultaneously. We attribute this to the physical structure and the aggregated nature of the undisturbed soil material . This results in the presence of spatially disjoint oxidative and reductive regions of microbial activity and requires, but is not fully reflected by a dual porosity model. Currently, the numerical simulation of this system is in progress, considering several flow and transport models. A stochastic global search algorithm (DREAM-ZS) is used in conjuction with HYDRUS-1D to avoid local minima in the inverse simulations. The study shows the current limitations and potentials of modeling degradation in an aggregated and structured system under flow conditions.

Mineral resource of the month: salt

USGS Publications Warehouse

Kostick, Dennis S.

2010-01-01

The article presents information on various types of salt. Rock salt is either found from underground halite deposits or near the surface. Other types of salt include solar salt, salt brine, and vacuum pan salt. The different uses of salt are also given including its use as a flavor enhancer, as a road deicing agent, and to manufacture sodium hydroxide.

7 CFR 3201.37 - General purpose de-icers.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) that are designed to aid in the removal of snow and/or ice, and/or in the prevention of the buildup of snow and/or ice, in general use applications by lowering the freezing point of water. Specialized de-icer products, such as those used to de-ice aircraft and airport runways, are not included. (b) Minimum...

7 CFR 3201.37 - General purpose de-icers.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) that are designed to aid in the removal of snow and/or ice, and/or in the prevention of the buildup of snow and/or ice, in general use applications by lowering the freezing point of water. Specialized de-icer products, such as those used to de-ice aircraft and airport runways, are not included. (b) Minimum...

7 CFR 3201.37 - General purpose de-icers.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) that are designed to aid in the removal of snow and/or ice, and/or in the prevention of the buildup of snow and/or ice, in general use applications by lowering the freezing point of water. Specialized de-icer products, such as those used to de-ice aircraft and airport runways, are not included. (b) Minimum...

7 CFR 2902.37 - General purpose de-icers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... are designed to aid in the removal of snow and/or ice, and/or in the prevention of the buildup of snow and/or ice, in general use applications by lowering the freezing point of water. Specialized de-icer products, such as those used to de-ice aircraft and airport runways, are not included. (b) Minimum biobased...

7 CFR 2902.37 - General purpose de-icers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... are designed to aid in the removal of snow and/or ice, and/or in the prevention of the buildup of snow and/or ice, in general use applications by lowering the freezing point of water. Specialized de-icer products, such as those used to de-ice aircraft and airport runways, are not included. (b) Minimum biobased...

77 FR 59873 - Airworthiness Directives; Cessna Aircraft Company Airplanes; Initial Regulatory Flexibility Analysis

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-01

... should be flown into known icing. However, the original certification basis for these airplanes did not incorporate Amendment 7 (May 3, 1962) of CAR 3, requiring manufacturers to provide a placard specifying the... aircraft is limited by the equipment installed (CAR 3 Sec. 3.772). As a result, with operational deicing...

Three Permeable Pavements Performances for Priority Metal Pollutants and Metals associated with Deicing Chemicals from Edison Parking Lot, NJ - abstract

EPA Science Inventory

The U.S. Environmental Protection Agency constructed a 4000-m2 parking lot in Edison, New Jersey in 2009. The parking lot is surfaced with three permeable pavements [permeable interlocking concrete pavers (PICP), pervious concrete (PC), and porous asphalt (PA)]. Samples of each p...

14 CFR 27.1093 - Induction system icing protection.

Code of Federal Regulations, 2010 CFR

2010-01-01

...— (i) 100 degrees F.; or (ii) If a fluid deicing system is used, at least 40 degrees F. (b) Turbine engine. (1) It must be shown that each turbine engine and its air inlet system can operate throughout the.... (2) Each turbine engine must idle for 30 minutes on the ground, with the air bleed available for...

14 CFR 27.1093 - Induction system icing protection.

Code of Federal Regulations, 2012 CFR

2012-01-01

...— (i) 100 degrees F.; or (ii) If a fluid deicing system is used, at least 40 degrees F. (b) Turbine engine. (1) It must be shown that each turbine engine and its air inlet system can operate throughout the.... (2) Each turbine engine must idle for 30 minutes on the ground, with the air bleed available for...

14 CFR 27.1093 - Induction system icing protection.

Code of Federal Regulations, 2011 CFR

2011-01-01

...— (i) 100 degrees F.; or (ii) If a fluid deicing system is used, at least 40 degrees F. (b) Turbine engine. (1) It must be shown that each turbine engine and its air inlet system can operate throughout the.... (2) Each turbine engine must idle for 30 minutes on the ground, with the air bleed available for...

14 CFR 27.1093 - Induction system icing protection.

Code of Federal Regulations, 2014 CFR

2014-01-01

...— (i) 100 degrees F.; or (ii) If a fluid deicing system is used, at least 40 degrees F. (b) Turbine engine. (1) It must be shown that each turbine engine and its air inlet system can operate throughout the.... (2) Each turbine engine must idle for 30 minutes on the ground, with the air bleed available for...

14 CFR 27.1093 - Induction system icing protection.

Code of Federal Regulations, 2013 CFR

2013-01-01

...— (i) 100 degrees F.; or (ii) If a fluid deicing system is used, at least 40 degrees F. (b) Turbine engine. (1) It must be shown that each turbine engine and its air inlet system can operate throughout the.... (2) Each turbine engine must idle for 30 minutes on the ground, with the air bleed available for...

Multi-Channel, Constant-Current Power Source for Aircraft Applications

DTIC Science & Technology

2017-03-01

Special considerations impacting this design were minimizing volume, maintaining system power quality, and providing electrical fault protection...applications. Electrical loads, such as lighting, de-icing heaters, and actuators may be operated from this compact power conversion unit. Because of the...nature of aircraft systems, two of the most important design considerations are the maintenance of electrical power quality and minimization of weight

14 CFR Special Federal Aviation... - Mitsubishi MU-2B Series Special Training, Experience, and Operating Requirements

Code of Federal Regulations, 2010 CFR

2010-01-01

.... Fuselage 2. Wing 3. Empennage 4. Doors 5. Windshield and Windows C. Airplane Systems 1. Electrical Power 2... System 1. Navigation Lights 2. Anti-Collision Lights 3. Wing Inspection Lights 4. Taxi Lights 5. Landing... Operations 3. Synchronization 4. De-Ice D. Ground Checks 1. Overspeed Governor 2. SRL and Delta P/P 3. NTS...

14 CFR Special Federal Aviation... - Mitsubishi MU-2B Series Special Training, Experience, and Operating Requirements

Code of Federal Regulations, 2011 CFR

2011-01-01

.... Fuselage 2. Wing 3. Empennage 4. Doors 5. Windshield and Windows C. Airplane Systems 1. Electrical Power 2... System 1. Navigation Lights 2. Anti-Collision Lights 3. Wing Inspection Lights 4. Taxi Lights 5. Landing... Operations 3. Synchronization 4. De-Ice D. Ground Checks 1. Overspeed Governor 2. SRL and Delta P/P 3. NTS...

De-Icing of Aircraft Turbine Engine Inlets

DTIC Science & Technology

1988-06-01

W0OO Aviona Marcel Dassault TFE731 -3 tirbolan Falcon 50 Avlons Maircel Dsasaau ATF34A Turbolan Falcon 200 Avian* Marcel Dassault ATF3.6 1b.bolan HU25A...Aviana Maemel Dassault TFE731 -4A Turbolan Falcon 900 Avion@ Marcel Dassault J73D 1Ubots 797 Boeing .1110 )Irbotkn 727 Boeing .1750 TUrbolan 737 Boeing

Anaerobic digestion of aircraft deicing fluid wastes: interactions and toxicity of corrosion inhibitors and surfactants.

PubMed

Gruden, Cyndee L; Hernandez, Mark

2002-01-01

Corrosion inhibitors and surfactants are present in aircraft deicing fluids (ADFs) at significant concentrations (> 1% w/w). The purpose of this research was to study the interactions of a common nonionic surfactant with the commercially significant corrosion inhibitors used in modern ADF (4- and 5-methylbenzotriazole [MeBT]), and to determine the effects of their mixture on the conventional anaerobic digestion process. In mesophilic anaerobic microcosms codigesting wastewater solids, propylene glycol, and MeBT, increasing surfactant levels resulted in enhanced MeBT sorption on digester solids. As judged by anaerobic toxicity assays, responses from digesters containing surfactant concentrations below their critical micelle concentration (CMC) suggested that low nonionic surfactant concentrations could facilitate a reduction in the apparent toxicity of MeBT. In microcosms exposed to surfactant concentrations above their CMC, no increase in MeBT solubility was observed, and the anaerobic toxicity response corresponded to control systems not containing surfactant. Direct microscopic measurements of digesting biomass using fluorescent phylogenetic probes (fluorescent in situ hybridization) revealed that members of the domain Bacteria were more sensitive to MeBT in the presence of surfactant than were members of the domain Archaea.

Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 2. Toxicity of aircraft and runway deicers.

PubMed

Corsi, S R; Hall, D W; Geis, S W

2001-07-01

Streams receiving runoff from General Mitchell International Airport (GMIA), Milwaukee, Wisconsin, USA, were studied to assess toxic impacts of aircraft and runway deicers. Elevated levels of constituents related to deicing (propylene glycol, ethylene glycol, and ammonia) were observed in stream samples. The LC50s of type I deicer for Ceriodaphnia dubia, Pimephelas promelas, Hyalela azteca, and Chironimus tentans and the EC50 for Microtox were less than 5,000 mg/L of propylene glycol. Concentrations up to 39,000 mg/L were observed at airport outfall sites in samples collected during deicing events. The IC25s of type I deicer for C. dubia and P. promelas were less than 1,500 mg/L of propylene glycol. Concentrations up to 960 mg/L were observed in low-flow samples at an airport outfall site. Measured toxicity of stream water was greatest during winter storms when deicers were applied. Chronic toxicity was observed at airport outfall samples from low-flow periods in the winter and the summer, with the greater toxic impacts from the winter sample. All forms of toxicity in stream-water samples decreased as downstream flows increased.

An experimental study of icing control using DBD plasma actuator

NASA Astrophysics Data System (ADS)

Cai, Jinsheng; Tian, Yongqiang; Meng, Xuanshi; Han, Xuzhao; Zhang, Duo; Hu, Haiyang

2017-08-01

Ice accretion on aircraft or wind turbine has been widely recognized as a big safety threat in the past decades. This study aims to develop a new approach for icing control using an AC-DBD plasma actuator. The experiments of icing control (i.e., anti-/de-icing) on a cylinder model were conducted in an icing wind tunnel with controlled wind speed (i.e., 15 m/s) and temperature (i.e., -10°C). A digital camera was used to record the dynamic processes of plasma anti-icing and de-icing whilst an infrared imaging system was utilized to map the surface temperature variations during the anti-/de-icing processes. It was found that the AC-DBD plasma actuator is very effective in both anti-icing and de-icing operations. While no ice formation was observed when the plasma actuator served as an anti-icing device, a complete removal of the ice layer with a thickness of 5 mm was achieved by activating the plasma actuator for ˜150 s. Such information demonstrated the feasibility of plasma anti-/de-icing, which could potentially provide more effective and safer icing mitigation strategies.

Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 2. Toxicity of aircraft and runway deicer

USGS Publications Warehouse

Corsi, Steven; Hall, David W.; Geis, Steven W.

2001-01-01

Streams receiving runoff from General Mitchell International Airport (GMIA), Milwaukee, Wisconsin, USA, were studied to assess toxic impacts of aircraft and runway deicers. Elevated levels of constituents related to deicing (propylene glycol, ethylene glycol, and ammonia) were observed in stream samples. The LC50s of type I deicer for Ceriodaphnia dubia, Pimephelas promelas, Hyalela azteca, and Chironimus tentans and the EC50 for Microtox® were less than 5,000 mg/L of propylene glycol. Concentrations up to 39,000 mg/L were observed at airport outfall sites in samples collected during deicing events. The IC25s of type I deicer for C. dubia and P. promelas were less than 1,500 mg/L of propylene glycol. Concentrations up to 960 mg/L were observed in low-flow samples at an airport outfall site. Measured toxicity of stream water was greatest during winter storms when deicers were applied. Chronic toxicity was observed at airport outfall samples from low-flow periods in the winter and the summer, with the greater toxic impacts from the winter sample. All forms of toxicity in stream-water samples decreased as downstream flows increased.

Ice on waterfowl markers

USGS Publications Warehouse

Greenwood, R.J.; Bair, W.C.

1974-01-01

Wild and captive giant Canada geese (Branta canadensis maxima) and captive mallards (Anas platyrhynchos) accumulated ice on neck collars and/or nasal saddles during winter storm periods in 1971 and 1972. Weather conditions associated with icing were documented, and characteristics of icing are discussed. Severe marker icing occurred during subfreezing weather when the windchill reached approximately -37 deg.C. Birds appeared able to de-ice nasal saddles in most instances.

Protection against wing icing for Airbus A300 and A310

NASA Technical Reports Server (NTRS)

Woelfer, G.

1981-01-01

To improve economy of operation, it is now planned to modify the anti-icing system used on the A300 Airbus wing. Thus, for the A310 Airbus, the deicing system will be applied to only half the wing length. Other essential modifications are a substantial simplification of the warm-air system and discontinuation of the use of a double wall in slats.

NACA Conference on Aircraft Ice Prevention - A Compilation of the Paper Presented by NACA Staff Members on 26-27 Jun 1947

DTIC Science & Technology

1947-06-01

by two shielded thermocouples located approximately 15 feet dom1stream of the cooling fan. A battery of four stroboscopic flash lamps ~ermitted...8217emaining on the blades after cyclical de-icing wi tll the exter.no.l beater . IH tb tbe exce;_;tion of investiga- liions ruade at alr cemperatures

Demonstration of an Environmentally Benign and Reduced Corrosion Runway Deicing Fluid

DTIC Science & Technology

2011-01-01

ADDRESS(ES) Enviromental Security Technology Certification Program: 901 North Stuart Street, Suite 303, Arlington, Virginia 22203 10. SPONSOR...IMPLEMENTATION ISSUES Users may express concern because the Battelle-RDF is new and they may have reservations because of its potential damage to...several drivers for implementing a new , more environmentally friendly RDF. 1.3.1 Water Pollution Reduction The Clean Water Act (CWA) and its

The De-Icing Comparison Experiment (D-ICE): A campaign for improving data retention rates of radiometric measurements under icing conditions in cold regions

NASA Astrophysics Data System (ADS)

Cox, C. J.; Morris, S. M.

2017-12-01

Longwave and shortwave radiative fluxes are fundamental quantities regularly observed globally using broadband radiometers. In cold climates, frost, rime, snow and ice (collectively, "icing") frequently builds up on sensor windows, contaminating measurements. Since icing occurs under particular meteorological conditions, associated data losses constitutes a climatological bias. Furthermore, the signal caused by ice is difficult to distinguish from that of clouds, hampering efforts to identify contaminated from real data in post-processing. Because of the sensitivity of radiometers to internal temperature instabilities, there are limitations to using heat as a de-icing method. The magnitude of this problem is indicated by the large number of research institutions and commercial vendors that have developed various de-icing strategies. The D-ICE campaign has been designed to bring together a large number of currently available systems to quantitatively evaluate and compare ice-migration strategies and also to characterize the potentially adverse effects of the techniques themselves. For D-ICE, a variety of automated approaches making use of ventilation, heating, modified housings and alcohol spray are being evaluated alongside standard units operating with only the regularly scheduled manual cleaning by human operators at the NOAA Baseline Surface Radiation Network (BSRN) station in Utqiaġvik (formerly Barrow), Alaska. Previous experience within the BSRN community suggests that aspiration of ambient air alone may be sufficient to maintain ice-free radiometers without increasing measurement uncertainty during icing conditions, forming the main guiding hypothesis of the experiment. Icing on the sensors is monitored visually using cameras recording images every 15 minutes and quantitatively using an icing probe and met station. The effects of applied heat on infrared loss in pyranometers will be analyzed and the integrated effect of icing on monthly averages will be assessed by comparing ice-mitigated and unmitigated systems. The project is a community effort led by NOAA in collaboration with the BSRN Cold Climates Issues Working Group (CCIWG) in partnership with industry representatives and research institutes. The campaign will operate for a full annual cycle from August 2017 through 2018.

Unidirectional Core-Shell Hybrids for Concrete Reinforcement - A preliminary Study

DTIC Science & Technology

1994-02-01

angle with respect to the rebar longitudinal axis. 14. SUBJECT TERMS 115. WNUMER OF PAGES FRP, rebar , concrete , fibers, carbon fibers, glass fibers...structures. The main cause of deterioration is concrete cracking and corrosion of steel reinforcement exposed to the marine environment and aggressive...agents such as deicing salts for bridges and pavements . To prevent this corrosion , galvanized and epoxy-coated steel reinforcing bars are currently being

Enhanced Biological Attenuation of Aircraft Deicing Fluid Runoff Using Constructed Wetlands

DTIC Science & Technology

2004-09-01

treatment wetlands have variable water column oxygen levels depending on several factors. Atmospheric diffusion, wind action, algae, and macrophytes ...visible to the unassisted eye are called macrophytes and include the vascular, herbaceous, and woody species common to wetland environments. Microbes are...of pH in treatment wetlands shows that typical operational pH levels range from 6.5 to 7.5 13. Rooted wetland macrophytes also actively transport

Toxicity of Tolyltriazole to Bacillus Microorganisms.

DTIC Science & Technology

2000-03-01

been done on the chemical additives [Jank et al, 1974; Kaplan et al, 1982; Raja et al, 1991; Strong-Gunderson et al, 1995; Bausmith and Neufeld, 1996...ADAF is over 3,000 times the COD of typical untreated domestic wastewater [ Bausmith and Neufeld 460]. Chain length and molecular weights of glycols...mtox.htm Bausmith , David S. and Ronald D. Neufeld. "Soil Biodegradation of Propylene Glycol Based Aircraft Deicing Fluids," Water Environment

Sorption of the Aircraft Deicing Fluid Component Methyl-Benzotriazole in Soil

DTIC Science & Technology

1999-03-01

Atlas , Ronald M., Bartha , Richard, Microbial Ecology : Fundamentals and Applications. Benjamin Cummings: Redwood City, 1993. Ball, William P., Roberts...cell; transfer of substances from one medium to another [ Atlas and Bartha , 533; Fetter, 117]. (2) The process by which a compound in solution or...oxygen, low redox potential. [ Atlas and Bartha , 534; Schwarzenbach et al, 410] Aromatic compound - Carbon skeletons containing aromatic benzene ring and

Digital analysis of wind tunnel imagery to measure fluid thickness

NASA Technical Reports Server (NTRS)

Easton, Roger L., Jr.; Enge, James

1992-01-01

Documented here are the procedure and results obtained from the application of digital image processing techniques to the problem of measuring the thickness of a deicing fluid on a model airfoil during simulated takeoffs. The fluid contained a fluorescent dye and the images were recorded under flash illumination on photographic film. The films were digitized and analyzed on a personal computer to obtain maps of the fluid thickness.

Alkali-aggregate reaction under the influence of deicing salts in the Hokuriku district, Japan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katayama, Tetsuya; Tagami, Masahiko; Sarai, Yoshinori

2004-11-15

Concrete cores taken from highway bridges and culverts undergoing alkali-silica reaction (ASR) were investigated petrographically by means of core scanning, point counting, polarizing microscopy, scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), electron-probe microanalysis with energy-dispersive spectrometry, in conjunction with wet chemical analyses and expansion tests. Field damage was roughly proportional to the content of andesite in the gravel aggregates due to the presence of highly reactive cristobalite and tridymite. Electron-probe microanalyzer analysis of unhydrated cement phases in the concrete revealed that the cement used had contained at least 0.5% to 1.0% alkali (Na{sub 2}Oeq) and that both the aggregatesmore » and the deicing salts had supplied part of the water-soluble alkali to concrete toward the threshold of producing ASR (Na{sub 2}O{sub eq} 3.0 kg/m{sup 3}). An accelerated concrete core expansion test (1 M NaOH, 80 deg. C) of the damaged structures mostly gave core expansions of >0.10% at 21 days (or >0.05% at 14 days), nearly comparable to those of a slow expansion test with saturated NaCl solution (50 deg. C, 91 days) which produced Cl-containing ASR gel.« less

Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 1. Biochemical oxygen demand and dissolved oxygen in receiving streams.

PubMed

Corsi, S R; Booth, N L; Hall, D W

2001-07-01

Aircraft and runway deicers are used during cold weather at many of the world's airports to facilitate safe air travel. Propylene glycol-, ethylene glycol-, and urea-based deicers are known to have very high biochemical oxygen demand. At General Mitchell International Airport (GMIA) in Milwaukee, Wisconsin, USA, deicer application, water chemistry, and dissolved oxygen (DO) data were collected for two deicing seasons in order to evaluate and define premanagement water quality parameters prior to the implementation of a glycol management program. Calculations using stream-monitoring data during a controlled release of deicer provided an estimate of 0.8/d for the first-order decay rate constant, substantially higher than published laboratory test results. For eight precipitation events with deicing activities, between 2.4 and 99% of propylene and ethylene glycol applied to aircraft was delivered directly to receiving streams. The percentage of glycol runoff during an event increased with increasing storm-flow volume. Elevated concentrations of glycol and biochemical oxygen demand were measured downstream from the airport. However, the frequency of low DO concentrations in the receiving streams is comparable with that at an upstream reference site. This is possibly due to slowed bacteria metabolism at low water temperatures, short travel times, and dilution from downstream tributaries.

Metasurfaces Leveraging Solar Energy for Icephobicity.

PubMed

Mitridis, Efstratios; Schutzius, Thomas M; Sicher, Alba; Hail, Claudio U; Eghlidi, Hadi; Poulikakos, Dimos

2018-06-29

Inhibiting ice accumulation on surfaces is an energy-intensive task and is of significant importance in nature and technology where it has found applications in windshields, automobiles, aviation, renewable energy generation, and infrastructure. Existing methods rely on on-site electrical heat generation, chemicals, or mechanical removal, with drawbacks ranging from financial costs to disruptive technical interventions and environmental incompatibility. Here we focus on applications where surface transparency is desirable and propose metasurfaces with embedded plasmonically enhanced light absorption heating, using ultrathin hybrid metal-dielectric coatings, as a passive, viable approach for de-icing and anti-icing, in which the sole heat source is renewable solar energy. The balancing of transparency and absorption is achieved with rationally nanoengineered coatings consisting of gold nanoparticle inclusions in a dielectric (titanium dioxide), concentrating broadband absorbed solar energy into a small volume. This causes a > 10 °C temperature increase with respect to ambient at the air-solid interface, where ice is most likely to form, delaying freezing, reducing ice adhesion, when it occurs, to negligible levels (de-icing) and inhibiting frost formation (anti-icing). Our results illustrate an effective unexplored pathway toward environmentally compatible, solar-energy-driven icephobicity, enabled by respectively tailored plasmonic metasurfaces, with the ability to design the balance of transparency and light absorption.

The Bridge of Mandolin County

NASA Astrophysics Data System (ADS)

Lantz, Juliette M.; Feindt, Jenny E.; Lewellyn, Eric P. B.; Walczak, Mary M.

1999-12-01

The Bridge of Mandolin County is a case designed to teach the general chemistry principles of molar mass, ions and aqueous reactions, solubility rules, and inorganic nomenclature. Through the instructor-facilitated class discussion, students consider the options before the Mandolin Town Council regarding deicing the newly constructed bridge connecting Mandolin with a large nearby city. The students must decipher contradictory claims made on behalf of sodium chloride, the traditional deicer, and calcium magnesium acetate, a new environmentally friendly deicer, to arrive at the most cost-effective and environmentally appropriate deicing product. As they work through the analysis they raise questions that can be addressed in a laboratory setting. Four optional role-playing experiments are included, which can be used by the students to gather information helpful to resolution of the case. The case is intended to be used over two class periods, with a laboratory period in between, though suggestions for other models are provided. Laboratory procedures include an EDTA titration for Ca2+ and Mg2+, a gravimetric analysis, a qualitative examination of ions and solubility, an introduction to freezing point depression and measurement, and an experimental design activity. This case can also successfully be used without alteration in non-majors chemistry or environmental chemistry courses, or upper-level analytical or environmental chemistry courses.

Analytical procedures for the determination of fuel combustion products, anti-corrosive compounds, and de-icing compounds in airport runoff water samples.

PubMed

Sulej, Anna Maria; Polkowska, Żaneta; Astel, Aleksander; Namieśnik, Jacek

2013-12-15

The purpose of this study is to propose and evaluate new procedures for determination of fuel combustion products, anti-corrosive and de-icing compounds in runoff water samples collected from the airports located in different regions and characterized by different levels of the activity expressed by the number of flights and the number of passengers (per year). The most difficult step in the analytical procedure used for the determination of PAHs, benzotriazoles and glycols is sample preparation stage, due to diverse matrix composition, the possibility of interference associated with the presence of components with similar physicochemical properties. In this study, five different versions of sample preparation using extraction techniques, such as: LLE and SPE, were tested. In all examined runoff water samples collected from the airports, the presence of PAH compounds and glycols was observed. In majority of the samples, BT compounds were determined. Runoff water samples collected from the areas of Polish and British international airports as well as local airports had similar qualitative composition, but quantitative composition of the analytes was very diverse. New and validated analytical methodologies ensure that the necessary information for assessing the negative impact of airport activities on the environment can be obtained. © 2013 Elsevier B.V. All rights reserved.

Aircraft and runway deicers at General Mitchell International Airport, Milwaukee, Wisconsin, USA. 1. Biochemical oxygen demand and dissolved oxygen in receiving streams

USGS Publications Warehouse

Corsi, S.R.; Booth, N.L.; Hall, D.W.

2001-01-01

Aircraft and runway deicers are used during cold weather at many of the world's airports to facilitate safe air travel. Propylene glycol-, ethylene glycol-, and urea-based deicers are known to have very high biochemical oxygen demand. At General Mitchell International Airport (GMIA) in Milwaukee, Wisconsin, USA, deicer application, water chemistry, and dissolved oxygen (DO) data were collected for two deicing seasons in order to evaluate and define premanagement water quality parameters prior to the implementation of a glycol management program. Calculations using stream-monitoring data during a controlled release of deicer provided an estimate of 0.8/d for the first-order decay rate constant, substantially higher than published laboratory test results. For eight precipitation events with deicing activities, between 2.4 and 99% of propylene and ethylene glycol applied to aircraft was delivered directly to receiving streams. The percentage of glycol runoff during an event increased with increasing storm-flow volume. Elevated concentrations of glycol and biochemical oxygen demand were measured downstream from the airport. However, the frequency of low DO concentrations in the receiving streams is comparable with that at an upstream reference site. This is possibly due to slowed bacteria metabolism at low water temperatures, short travel times, and dilution from downstream tributaries.

Ice Detection and Mitigation Device

NASA Technical Reports Server (NTRS)

Gambino, Richard J. (Inventor); Gouldstone, Christopher (Inventor); Gutleber, Jonathan (Inventor); Hubble, David (Inventor); Trelewicz, Jason (Inventor)

2016-01-01

A method for deicing an aerostructure includes driving a sensing current through a heater element coated to an aerostructure, the heater element having a resistance that is temperature dependent. A resistance of the heater element is monitored. It is determined whether there is icing at the heater element using the monitored resistance of the heater element. A melting current is driven through the heater element when it is determined that there is icing at the heater element.

Demonstrate a Low Biochemical Oxygen Demand Aircraft Deicing Fluid

DTIC Science & Technology

2013-03-01

Technologies International, LTD for collection and recycling of fluids. Spent fluid, diluted with any water, slush or snow removed from the aircraft or...Resistance Unmated only – some failures Voltage Withstand Testing Unmated only – some failures Plastic Windows Crazing Effect Pass The testing did result...At Joint Base McGuire-Dix-Lakehurst, however, waste PG is currently collected with a vacuum truck and recycled . Factors such as the market demand

Demonstrate a Low Biochemical Oxygen Demand Aircraft Deicing Fluid

DTIC Science & Technology

2013-03-04

Technologies International, LTD for collection and recycling of fluids. Spent fluid, diluted with any water, slush or snow removed from the aircraft or...Resistance Unmated only – some failures Voltage Withstand Testing Unmated only – some failures Plastic Windows Crazing Effect Pass The testing did result...At Joint Base McGuire-Dix-Lakehurst, however, waste PG is currently collected with a vacuum truck and recycled . Factors such as the market demand

Lamb Wave Propagation in Varying Thermal Environments

DTIC Science & Technology

2007-03-01

detection in structural joints (5). The Tacoma Narrows Bridge collapse, which occurred on 7 November 1940, was due to a torsional or twisting mode that...operational, the airframes can be subjected to temperature swings (-40°F to 150°F) and the corrosive effects of salts, de-icing agents, and several types...aircraft-grade aluminum plate study was used to verify wavespeed dispersion characteristics (7:428). Techniques similar to these are implemented in the

Active-Twist Rotor Control Applications for UAVs

NASA Technical Reports Server (NTRS)

Wilbur, Matthew L.; Wilkie, W. Keats

2004-01-01

The current state-of-the-art in active-twist rotor control is discussed using representative examples from analytical and experimental studies, and the application to rotary-wing UAVs is considered. Topics include vibration and noise reduction, rotor performance improvement, active blade tracking, stability augmentation, and rotor blade de-icing. A review of the current status of piezoelectric fiber composite actuator technology, the class of piezoelectric actuators implemented in active-twist rotor systems, is included.

Review of the Fiscal Year 2012 (FY12) Defense Environmental International Cooperation (DEIC) Program: Unclassified Version

DTIC Science & Technology

2013-06-01

engagement with the Armed Forces of the Philippines. During the 2012 Balikatan Exercise, sixteen technologies pertaining to humanitarian assistance ...special priority placed on projects that promote mission sustainment, innovative approaches to environment, safety and occupational health (ESOH...percent cut from its original budget. Part of this reduction came as a result of the Assistant DUSD(I&E) redirection of funding to support other I&E

Environmentally Benign Aircraft Anti-icing and Deicing Fluids Based on Cost Effective, Bio-based Ingredients

DTIC Science & Technology

2012-09-01

xanthan gum, welan gum, or carraggenan gum.(13) Examples of particulate thickeners include lightly cross-linked polyacrylic acid. Both types of ...based formulation.(14) The currently used Type IV AAFs are believed to primarily use polyacrylic acid (PAA) polymer, stabilized by potassium ...Prescribed by ANSI-Std Z39-18 REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information

Environmental Assessment Addressing Gate Complex Construction at Scott Air Force Base, Illinois

DTIC Science & Technology

2014-04-01

2014 221,760 No change I3. Construct Aircraft Deicing Pad, which would include an underground storage tank, a drainage system , and permanent lighting...Defense Information System Agency DNL day-night average A-weighted sound level DOD Department of Defense DOPAA Description of the Proposed Action...MWDs); a truck-inspection search office; a cargo-transfer facility; a mobile vehicle and cargo inspection system ; an over watch building; and a

Environmental Security Cooperation USARPAC’s: Defense Environmental and International Cooperation (DEIC) Conference (Center of Strategic Leadeship Issue Paper, Volume 07-03, September 2003)

DTIC Science & Technology

2003-09-01

infrastructure, and providing consequence management and mitigation of man-made and natural disasters. The United States Army, Pacifi c (USARPAC), the Offi...Terrorism, Disaster Response and Consequence Management , and Medical Aspects of Environmental Security. The conference brought together military and...consequence management in maintaining governmental legitimacy, and examine salient military roles in preventing, responding to, and mitigating natural

The environmental impact of 4(5)-methylbenzotriazole from aircraft deicing operations

NASA Astrophysics Data System (ADS)

Cornell, Jeffrey Scott

2002-01-01

Hundreds of millions of gallons of aircraft deicer fluid (ADF) are applied to aircraft and runway surfaces annually. Recently public and regulatory attention has forced the air transport industry and military aviation community to examine the environmental impacts of aircraft deicing operations (ADOs), and to seek a balance between flight safety and environmental impact. Little data exists which is useful to evaluate the impact of ADF additives. 4(5)-methylbenzotriazole (MeBT) is used in a variety of industrial and commercial fluids to inhibit metal corrosion; it is a standard additive to most common ADF (approx. 0.5%). This MeBT component is actually a mixture of two isomers: 4-methylbenzotriazole (4-MeBT) and 5-methylbenzotriazole (5-MeBT). A significant amount of MeBT enters the natural environment through aircraft deicing operations. Research was conducted to address important data gaps impacting the ability to assess the environmental impact of MeBT and ADOs. Matrixed toxicity studies were conducted to determine the effect of different additives on ADF ecotoxicity. Aerobic liquid batch-fed microcosms were employed to investigate how MeBT affects the toxicity of wastewater containing ADF, describe how MeBT affects the aerobic biodegradation of propylene glycol (PG), and determine the biodegradability of MeBT. Field samples from contaminated areas were collected and analyzed for comparison. Cell energy production and electron transport assays were conducted to determine if MeBT was capable of disrupting oxidative phosphorylation via uncoupling, as its chemical structure would suggest. MicrotoxRTM studies indicated MeBT was toxic to test bacteria below 10 mg/L. C. dubia and P. promelas , however, were less sensitive to MeBT than bacteria but more sensitive to other ADF additives. The effect of MeBT on PG biodegradation was complex and concentration-dependent. Cell yield and PG biodegradation rates generally decreased with increasing reactor MeBT concentration. ATP:INT assay data in bioreactors containing 10 mg McBT/L suggested ATP production uncoupled from electron transport. Oxygen consumption and aerobic PG biodegradation was completely inhibited between above 2,000 mg MeBT/L. MeBT was not degraded when PG was present above 0.5 mg/L in well-mixed aerobic conditions. 5-MeBT was biodegradable under a variety of aerobic laboratory conditions (when PG was not present) while 4-MeBT was recalcitrant.

Alternative Energy as an Engagement Opportunity in the USPACOM AOR

DTIC Science & Technology

2010-06-16

grid with fungible power the PUC can manage • Strengthen US image as a contributing partner in Palau’s economy • Provide a showpiece within the...person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number...nation of Palau, in partnership with: • ODUSD(I&E) Defense Environmental International Cooperation Program (DEIC) • US Army Corps of Engineers 249th

Chloride Sensitivity of the Corrosion Rate of Zinc-Coated Reinforcing Bars

DTIC Science & Technology

1976-09-01

wide use of deicing salts on highway pavements and bridges also represents a major source of concrete deterioration induced by rebar corrosion . Adding...cm] Cover in the Spall Zones 11 3a Underlayment of Trestle Showing Spalling of Concrete and Corrosion of Steel Supports 12 3b Deterioration of...Statement Concrete , when placed in cor.act with metals, may be corrosive , neutral, or protective. ihe response of metal to concrete depends on the alloy

JUH-1H Pneumatic Boot Deicing System Flight Test Evaluation

DTIC Science & Technology

1983-05-01

VRS) shown in figure 2, appendix D, were used to supplement pilot’s qualitative comments. Flight test data were recorded by hand and on magnetic tape...did not show significant reductions in deflation time and the auxiliary vent appeared to become clogged with what BFC called soapstone deposits... Soapstone is used during deicer pro- duction.) The second modification was applied to the inboard end of the deicers near blade station 51. The inboard

Polymer concrete overlay on SH-51, bridge deck

NASA Astrophysics Data System (ADS)

Borg, T. M.

1982-06-01

A thin resinous overlay was placed on a sound bridge deck in Oklahoma to evaluate its performance over one year using various physical tests. The evaluation shows how well the overlay protects the reinforcing steel from corrosion due to deicing salts. The steps leading to the construction of the overlay are detailed as well as the actual placing of the overlay. The results of various physical tests are reported for both before and after the overlay.

A heater made from graphite composite material for potential deicing application

NASA Technical Reports Server (NTRS)

Hung, C. C.; Stahl, M.; Stahl, M.; Stahl, M.

1986-01-01

A surface heater was developed using a graphite fiber-epoxy composite as the heating element. This heater can be thin, highly electrically and thermally conductive, and can conform to an irregular surface. Therefore it may be used in an aircraft's thermal deicing system to quickly and uniformly heat the aircraft surface. One-ply of unidirectional graphite fiber-epoxy composite was laminated between two plies of fiber glass-epoxy composite, with nickel foil contacting the end portions of the composite and partly exposed beyond the composites for electrical contact. The model heater used brominated P-100 fibers from Amoco. The fiber's electrical resistivity, thermal conductivity and density were 50 micro ohms per centimeter, 270 W/m-K and 2.30 gm/cubic cm, respectively. The electricity was found to penetrate through the composite in the transverse direction to make an acceptably low foil-composite contact resistance. When conducting current, the heater temperature increase reached 50 percent of the steady state value within 20 sec. There was no overheating at the ends of the heater provided there was no water corrosion. If the foil-composite bonding failed during storage, liquid water exposure was found to oxidize the foil. Such bonding failure may be avoided if perforated nickel foil is used, so that the composite plies can bond to each other through the perforated holes and therefore lock the foil in place.

Density currents in the Chicago River: Characterization, effects on water quality, and potential sources

USGS Publications Warehouse

Jackson, P. Ryan; Garcia, Carlos M.; Oberg, Kevin A.; Johnson, Kevin K.; Garcia, Marcelo H.

2008-01-01

Bidirectional flows in a river system can occur under stratified flow conditions and in addition to creating significant errors in discharge estimates, the upstream propagating currents are capable of transporting contaminants and affecting water quality. Detailed field observations of bidirectional flows were made in the Chicago River in Chicago, Illinois in the winter of 2005-06. Using multiple acoustic Doppler current profilers simultaneously with a water-quality profiler, the formation of upstream propagating density currents within the Chicago River both as an underflow and an overflow was observed on three occasions. Density differences driving the flow primarily arise from salinity differences between intersecting branches of the Chicago River, whereas water temperature is secondary in the creation of these currents. Deicing salts appear to be the primary source of salinity in the North Branch of the Chicago River, entering the waterway through direct runoff and effluent from a wastewater-treatment plant in a large metropolitan area primarily served by combined sewers. Water-quality assessments of the Chicago River may underestimate (or overestimate) the impairment of the river because standard water-quality monitoring practices do not account for density-driven underflows (or overflows). Chloride concentrations near the riverbed can significantly exceed concentrations at the river surface during underflows indicating that full-depth parameter profiles are necessary for accurate water-quality assessments in urban environments where application of deicing salt is common.

Effect of Ice Formations on Section Drag of Swept NACA 63A-009 Airfoil with Partial-Span Leading-Edge Slat for Various Modes of Thermal Ice Protection

NASA Technical Reports Server (NTRS)

VonGlahn, Uwe H.; Gray, Vernon H.

1954-01-01

The effects of primary and runback ice formations on the section drag of a 36 deg swept NACA 63A-009 airfoil section with a partial-span leading-edge slat were studied over a range of angles of attack from 2 to 8 deg and airspeeds up to 260 miles per hour for icing conditions with liquid-water contents ranging from 0.39 to 1.23 grams per cubic meter and datum air temperatures from 10 to 25 F. The results with slat retracted showed that glaze-ice formations caused large and rapid increases in section drag coefficient and that the rate of change in section drag coefficient for the swept 63A-009 airfoil was about 2-1 times that for an unswept 651-212 airfoil. Removal of the primary ice formations by cyclic de-icing caused the drag to return almost to the bare-airfoil drag value. A comprehensive study of the slat icing and de-icing characteristics was prevented by limitations of the heating system and wake interference caused by the slat tracks and hot-gas supply duct to the slat. In general, the studies showed that icing on a thin swept airfoil will result in more detrimental aerodynamic characteristics than on a thick unswept airfoil.

Anti-Icing Formulas Prevent Train Delays

NASA Technical Reports Server (NTRS)

2013-01-01

In the winter of 2009, Washington, DC, workers faced the prospect of a difficult commute due to record-setting snowfalls. But thousands of the city's Metrorail riders found the public transportation system fully functional, thanks in part to a NASA technology invented years before. Just like trains, an airplane must be snow- and ice-free to ensure safe travel. Traditionally, fluids containing a compound called ethylene glycol have been used to inhibit ice on planes. In 1992, however, the US Air Force banned its purchase of this ingredient due to toxicity concerns. According to the Centers for Disease Control, exposure to large amounts of ethylene glycol through air or water can damage the kidneys, nervous system, lungs, and heart. Urine samples from airport deicing workers have contained traces of the substance. At the time of the Air Force s ban, Robert Lockyer was working at NASA s Ames Research Center in the Advanced Composites Model Development Branch, where he says "we decided to pick up the gauntlet and began researching existing fluid compositions and the processes used in deicing aircraft." Along with Lockyer, in 1997 Ames researchers Leonard Haslim and John Zuk devised a nontoxic, biodegradable, and cost effective substitute for ethylene glycol. When applied to a dry surface before a snow or ice event, the solution prevented ice from forming a bond with the surface. This made it easy to wipe away any accumulation.

Modeling of Aircraft Deicing Fluid Induced Biochemical Oxygen Demand in Subsurface-Flow Constructed Treatment Wetlands

DTIC Science & Technology

2009-03-01

meters. The input and output control structures are modeled as sharp crested , rectangular weirs one meter in width. The elevation of the input weir is...manipulated by adjusting the width of both the input and output weirs and the crest height of the output weir . All of these adjustments were found to be...reduction of the weir crest height had an effect on the amount of storm water retained during low precipitation conditions, but not on the crest

Assessment of Superstructure Ice Protection as Applied to Offshore Oil Operations Safety: Problems, Hazards, Needs, and Potential Transfer Technologies

DTIC Science & Technology

2008-09-01

thermostats, or materials such as carbon layers, which vary in thickness with location and are self - healing and self - regulating. Ships commonly use heating...aircraft today. Pneumatic deicing systems consist of rubber or other elastomeric boots placed on the leading edge of an aircraft wing or on any surface...by Kenney, two as- semblies consisting of neoprene rubber and urethane-coated Dacron fabric were hung from bulkheads where icing would occur. A timer

Theoretical Bases of Polymer Photodegradation and Photooxidation,

DTIC Science & Technology

1987-10-15

UNCLASSIFIED FTD- AD(RS)T-E868-87 F/G 7/6 NL MhEEOEE~~h EhiIIIEEEEEI -M Mi(ROC PY RESOLUtIO(N TEST CHA NA ION- A j ~A M R ~ . DEiC FILE CME ( 1 ) FTD-ID...In addition, when such processes are carried out in an atmosphere of air, numerous carbonyl, carboxyl , hydroxyl etc. groups form along the polymer...photoaging this should be multilateral with consideration of the following basic processes [ 1 -93: ...... 1 . Photochemical reactions of the actual

New Ionic Liquids from Natural Products for Environmentally Benign Aircraft Deicing and Anti-Icing

DTIC Science & Technology

2010-12-10

cation, the preparation of ILs from choline and two GRAS food ingredients (artificial sweeteners ), saccharine and acesulfamate was recently published...In comparison, the synthetic imidazolium-based ILs were quite toxic (EC50 ~14 mg/L) in the same bioassay. Both ILs are water soluble, however...RTIL. This is true to a certain extent, but again the compound has a level of toxicity to C. dubia. Also, the ‘ synthetic ’ imidazolium-based IL 13

Pretreated Starch Solutions for Low Environmental Impact Aircraft Deicing

DTIC Science & Technology

2010-09-01

modified monomeric organic molecules, have been the focus of recent study. Several organic acids and keto acids, such as succinate and acetate, have...1992), but the authors noted low economic feasibility without additional recovered products. Ganjyal et al. (2007) produced levulinate, a keto acid...534 -23.4 25 -22.7 52 569 -25.3 5 -25.8 104 585 -28.0 Sigma Aldrich DARCO 12-20 Mesh 0 -28.0 143 634 -28.0 50 -26.2 100 626 -27.4 Calgon F-300 9

Icing: Accretion, Detection, Protection

NASA Technical Reports Server (NTRS)

Reinmann, John J.

1994-01-01

The global aircraft industry and its regulatory agencies are currently involved in three major icing efforts: ground icing; advanced technologies for in-flight icing; and tailplane icing. These three major icing topics correspondingly support the three major segments of any aircraft flight profile: takeoff; cruise and hold; and approach and land. This lecture addressess these three topics in the same sequence as they appear in flight, starting with ground deicing, followed by advanced technologies for in-flight ice protection, and ending with tailplane icing.

De-Icing Systems of Flight Vehicles. Bases of Design Methods for Testing. Part 1,

DTIC Science & Technology

1979-09-07

conducting filn; 2 - external glass; 3 - ela.tic Iajar; 4 - internal glass. Page 62. Therefore the film can be ueposited on many plastic transparent...specially developed polyester plastic "SayresijA-92011 dud of its varieties which many times are more stable agai.nst bcr~tches, than other transpar~r.t... plastics . Furthermore, aiii uaveoped the methcds of the restcratioji of glasses from solid plastic6 via the polishing of small/fine? scratches or with tho

Alternative aircraft anti-icing formulations with reduced aquatic toxicity and biochemical oxygen demand

USGS Publications Warehouse

Gold, Harris; Joback, Kevin; Geis, Steven; Bowman, George; Mericas, Dean; Corsi, Steven R.; Ferguson, Lee

2010-01-01

The current research was conducted to identify alternative aircraft and pavement deicer and anti-icer formulations with improved environmental characteristics compared to currently used commercial products (2007). The environmental characteristics of primary concern are the biochemical oxygen demand (BOD) and aquatic toxicity of the fully formulated products. Except when the distinction among products is necessary for clarity, “deicer” will refer to aircraft-deicing fluids (ADFs), aircraft anti-icing fluids (AAFs), and pavementdeicing materials (PDMs).

NASA Lewis Research Center's Program on Icing Research

NASA Technical Reports Server (NTRS)

Reinmann, J. J.; Shaw, R. J.; Olsen, W. A., Jr.

1982-01-01

The helicopter and general aviation, light transport, and commercial transport aircraft share common icing requirements: highly effective, lightweight, low power consuming deicing systems, and detailed knowledge of the aeropenalties due to ice on aircraft surfaces. To meet current and future needs, NASA has a broadbased icing research program which covers both research and engineering applications, and is well coordinated with the FAA, DOD, universities, industry, and some foreign governments. Research activity in ice protection systems, icing instrumentation, experimental methods, analytical modeling, and in-flight research are described.

Anaerobic biodegradation of aircraft deicing fluid in UASB reactors.

PubMed

Tham, P T Pham thi; Kennedy, K J Kevin J

2004-05-01

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions (0.8% 1.6% ADF (6000-12,000mg/L COD), 12-56h HRT, and 18-36gVSS/L) were conducted in continuous mode. The development of four empirical models describing process responses (i.e. COD removal efficiency, biomass-specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time, and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass-specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass-specific acetoclastic activity was improved two-fold from 0.23gCOD/gVSS/d for inoculum to a maximum of 0.55gCOD/gVSS/d during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. The predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate is increased. ADF toxicity effects were evident for 1.6% ADF at medium organic loadings (SOLR above 0.5gCOD/gVSS/d). In contrast, good reactor stability and excellent COD removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73gCOD/gVSS/d).

Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring, SoilCAM project highlights

NASA Astrophysics Data System (ADS)

French, H. K.; Van Der Zee, S. E.; Wehrer, M.; Godio, A.; Pedersen, L. B.; Tsocano, G.

2013-12-01

The SoilCAM project (2008- 2012, EU-FP7-212663) aimed at improving methods for monitoring subsurace contaminant distribution and biodegradation. Two test sites were chosen, Oslo airport Gardermoen, Norway where de-icing agents infiltrate the soil during snowmelt and the Trecate site in Italy where an inland crude oil spill occurred in 1994. A number of geophysical investigation techniques were combined with soil and water sampling techniques. Data obtained from time-lapse measurements were further analysed by numerical modelling of flow and transport at different scales in order to characterise transport processes in the unsaturated and saturated zones. Laboratory experiments provided physical and biogeochemical data for model parameterisation and to select remediation methods. The geophysical techniques were used to map geological heterogeneities and to conduct time-lapse measurements of processes in the unsaturated zone. Both cross borehole and surface electrodes were used for electrical resistivity and induced polarisation surveys. Results showed clear indications of areas highly affected by de-icing chemicals along the runway at Oslo airport. The time lapse measurements along the runway at the airport showed infiltration patterns during snowmelt and were used to validate 2D unsaturated flow and transport simulations using SUTRA. The simulations illustrate the effect of layering geological structures and membranes, buried parallel to the runway, on the flow pattern. Complex interaction between bio-geo-chemical processes in a 1D vertical profile along the runway were described with the ORCHESTRA model. Smaller scale field site measurements revealed increase of iron and manganese during degradation of de-icing chemicals. At the Trecate site a combination of georadar, electrical resistivity and radio magneto telluric provided a broad outline of the geology down to 50 m. Anomalies in the Induced polarisation and electrical resistivity data from the cross borehole measurements indicate where the remaining crude oil can be found. Water samples from multilevel samplers reveal crude oil present in emulsion in the zone of groundwater fluctuations, highlighting the importance of colloidal transport. Modelling of multiphase flow of the fluctuating groundwater level explains the lack of horizontal displacement of the plume in the area. Geochemistry of the groundwater clearly indicates degradation of hydrocarbons under iron- and sulphate reducing conditions, but changes were too slow to be mapped by time-lapse geophysical measurements during the project period. MODFLOW was used to simulate the regional groundwater flow and transport in the area. Highlights of the results from both test sites will be presented as an integrated overview. Snow removal at Oslo airport

The Development of an Advanced Anti-Icing/Deicing Capability for U.S. Army Helicopters. Volume 1. Design Criteria and Technology Considerations

DTIC Science & Technology

1975-11-01

EFFECT OF ICING CONDITIONS ON THE ZPG-2 AIRSHIP , NACA Technical Note 4220, Washington, D. C., April 1958. 28A * jb 7 -- ALBANYI I I,- 99 { T: FLINT...replicator (Figure 45) which featurek 35-mm slide frames coated with gelatine . Momentary exposure past an open slot leaves permanent footprints (cavi- ties...in the gelatine substance (Figure 46). In order to capture a true sample, the collection efficienuj of the collector (i.e., the fraction of 139 II r

Technical evaluation report, AGARD Fluid Dynamics Panel Symposium on Effects of Adverse Weather on Aerodynamics

NASA Technical Reports Server (NTRS)

Reinmann, J. J.

1991-01-01

The purpose of the meeting on Effects of Adverse Weather on Aerodynamics was to provide an update of the stae-of-the-art with respect to the prediction, simulation, and measurement of the effects of icing, anti-icing fluids, and various precipitation on the aerodynamic characteristics of flight vehicles. Sessions were devoted to introductory and survey papers and icing certification issues, to analytical and experimental simulation of ice frost contamination and its effects of aerodynamics, and to the effects of heavy rain and deicing/anti-icing fluids.

Report of the FAA International Conference on Airplane Ground Deicing Held in Reston, Virginia on May 28-29, 1992

DTIC Science & Technology

1992-05-29

Port of Seattle 10455 Metropolitan Blvd. P.O. Box 1209 PETER AMISH Montreal, PQ HIB -IAI Seattle, WA 98111 Northwest Airlines CANADA USA 5101 Northwest...PQ HIB lAI 703/689-4333 USA CANADA 214/988-3188x238 514/640-6400 MARC BRADELL Continental Airlines ALAN J. BILANIN JAMES E. BORSARI 8250 E. Smith Rd...20007-5201 CANADA 901/797-4159 USA 514/744-1511-1246 202/625-3500) STEVEN R. ERICKSON GEORGE H. EICHNER Air Transport Association PAUL DYKEMANN

Design and Testing of an Erosion Resistant Ultrasonic De-Icing System for Rotorcraft Blades

DTIC Science & Technology

2013-08-01

need for pneumatic slip rings , and the potential of holes located on the blade to clog. The 11-gallon tank adds significant weight and only protects...icing were the need of heavy pneumatic slip rings , and the need for a coating able to protect against both rain and sand erosion. 14 1.1.4.6...feet in diameter at an RPM of 1000 (see Figure 49). Four slip rings carry 48 signal channels and 24 power channels from the rotating frame of the

Electromagnetic Emissions from a Modular Low Voltage Electro-Impulse De-Icing System

DTIC Science & Technology

1989-03-01

composite wing section employed in these tests. Cy O’Young of the Boeing Commercial Airplance Company is thanked for his many he-pful suggestions during this...a voltage spike which occurred simultaneous wi’h the discharge of the coil. A 2.2 volt spike would be adequate to create a transmission error on a...signal was a voltage spike which occurs simultaneous with discharge of the coil. A 2.2 volt spike would be adequate to create an error on a digital

Non-invasive monitoring of the degradation of organic contaminants: A laboratory investigation

NASA Astrophysics Data System (ADS)

Fernandez, Perrine M.; Bloem, Esther; Philippe, Romain; Binley, Andrew; French, Helen K.

2016-04-01

Degradation of organic chemicals under various fluid saturation conditions is a process highly relevant to the protection of groundwater quality. Redox potential drives the degradation of organic compounds; its variation affects the water chemistry, gas release and also the geo-electrical signature. This study explores how non-invasive measurements sensitive to geo-electrical properties provides quantitative information about the in-situ redox conditions. Our laboratory experiment focuses on the degradation of de-icing chemicals commonly used, for example, in Norwegian airports. The experiment was conducted in a number of (1.0x0.5x0.4 m) sand boxes. Two ends of each box was contaminated with propylene glycol, an aircraft deicing fluid. Each source was placed near the water table under static hydraulic conditions. At one side of the tank, a conductor linking the contamination zone, near the water table and the unsaturated zone with a low water content, was placed to improve the degradation by facilitating the electron exchange. At the other side, degradation occurred under natural conditions. Each box was equipped with 288 electrodes, distributed on six faces to perform 3D resistivity measurements. In addition, self-potential measurements were taken from electrodes on the sand surface. Four observation wells were installed above and below the water table to provide more information on the degradation processes. Moreover, measurements of carbon dioxide on the surface were performed as higher concentrations were expected where the pollutant degraded. We would like to present and discuss a selection of the preliminary results of 3D electrical resistivity and self-potential techniques from our laboratory setup.

Effect of road deicing salt on the susceptibility of amphibian embryos to infection by water molds.

PubMed

Karraker, Nancy E; Ruthig, Gregory R

2009-01-01

Some causative agents of amphibian declines act synergistically to impact individual amphibians and their populations. In particular, pathogenic water molds (aquatic oomycetes) interact with environmental stressors and increase mortality in amphibian embryos. We documented colonization of eggs of three amphibian species, the wood frog (Rana sylvatica), the green frog (Rana clamitans), and the spotted salamander (Ambystoma maculatum), by water molds in the field and examined the interactive effects of road deicing salt and water molds, two known sources of mortality for amphibian embryos, on two species, R. clamitans and A. maculatum in the laboratory. We found that exposure to water molds did not affect embryonic survivorship in either A. maculatum or R. clamitans, regardless of the concentration of road salt to which their eggs were exposed. Road salt decreased survivorship of A. maculatum, but not R. clamitans, and frequency of malformations increased significantly in both species at the highest salinity concentration. The lack of an effect of water molds on survival of embryos and no interaction between road salt and water molds indicates that observations of colonization of these eggs by water molds in the field probably represent a secondary invasion of unfertilized eggs or of embryos that had died of other causes. Given increasing salinization of freshwater habitats on several continents and the global distribution of water molds, our results suggest that some amphibian species may not be susceptible to the combined effects of these factors, permitting amphibian decline researchers to devote their attention to other potential causes.

Influence of Superhydrophobic Properties on Deicing

NASA Astrophysics Data System (ADS)

Nazhipkyzy, M.; Mansurov, Z. A.; Amirfazli, A.; Esbosin, A.; Temirgaliyeva, T. S.; Lesbayev, B. T.; Aliyev, E. T.; Prikhodko, N. G.

2016-11-01

Nowadays the creation of anti-icing, or deicing, surfaces is one of the most important problems, as such surfaces are widely used in aeronautics, wind turbines, and telecommunication antennas. In this paper, we focus mainly on reducing the ice adhesion forces and easy ice removal, once ice has formed. Removal of a liquid from a surface can be provided by modification of the surface wettability by means of applying superhydrophobic coatings. Such coatings are water-resistant, i.e., are characterized by low water adhesion forces. To study the impact of superhydrophobic coatings, tests were performed on the surface of a wing in a wind tunnel. By spraying Teflon and polyphenylene sulfide (PPS) on the wing, we obtained a superhydrophobic film. This film has a structure that provides superhydrophobic properties, so that the wetting angle is above 140°. A comparison of the resulting surface with a clean Teflon one shows that adhesion of the Teflon + PPS mixture to an aluminum surface is five times higher. We also investigate the degree of ice formation on the surfaces of simple and superhydrophobic aircraft wings at a temperature of -18°C. It was shown that ice was formed on a simple wing within 40 s and on a superhydrophobic wing within 25 s. When the simple wing with a mass of 23 g was inserted into the wind tunnel, its mass reached 50 g, and for a superhydrophobic wing with a mass of 26 g the latter reached 42 g. The sample of the airfoil wing we prepared has a low adhesion, which helps in easy ice removal.

3D resistivity method to monitor degradation of an organic contaminant in sand boxes

NASA Astrophysics Data System (ADS)

Fernandez, P. M.; Bloem, E.; Philippe, R.; French, H. K.

2015-12-01

Degradation of organic chemicals under various saturation conditions is a process highly relevant to protect groundwater. The redox potential drives the degradation of organic compounds. Its variation affects the water chemistry, gas release and responses of the geo-electrical signature. This study explores how non-invasive measurements sensitive to geo-electrical properties provides quantitative information about the in-situ redox situation. During this presentation, the preliminary results of a laboratory experiment to study the degradation of deicing chemicals with 3D resistivity and self-potential techniques, water samples will be shown. The experiment consists of sand boxes (1.0x0.5x0.4 m) to which both sides of each box is contaminated with propylene glycol, an aircraft deicing fluid, commonly used in Norwegian airports. Each source is placed near the water table with static conditions. At one side a conductor is placed, linking the contamination zone at the water table and the unsaturated zone with a low water content, to improve the degradation by facilitating the electron exchange. At the other side, degradation occurs under natural conditions. Each box is equipped with 288 electrodes, distributed on six faces to perform 3D resistivity measurements. In addition to the resistivity, self-potential measurements are taken from the sand surface. Six water wells are installed above and below the water table to provide more information on the degradation processes. Moreover, measurements of carbon dioxide on the surface are performed as higher concentrations are expected where the pollutant is degraded.

The Development of an Advanced Anti-Icing/Deicing Capability for U.S. Army Helicopters. Volume II. Ice Protection System Application to the UH-1H helicopter

DTIC Science & Technology

1975-11-01

Project Lfgineer for this effort was ]Richard I. Adin of tL* eta ~ ’ -’ ’. -. - " - -ý - - , I - OWLAMWRS The 01 Mp io Otis vap am wae to No conmved an...area. One is the ultrasonic type and the second is the infrared occlusion type. Both sensors include aspirators using engine compressor bleed air to...half pound per minute of enginie bleed air to operate the aspirator . The principal benefit of the aspiration is during hover, as there is sufficient

Icephobicity and the effect of water condensation on the superhydrophobic low-density polyethylene surface

NASA Astrophysics Data System (ADS)

Yuan, Zhiqing; Wang, Menglei; Huang, Juan; Wang, Xian; Bin, Jiping; Peng, Chaoyi; Xing, Suli; Xiao, Jiayu; Zeng, Jingcheng; Xiao, Ximei; Fu, Xin; Gong, Huifang; Zhao, Dejian; Chen, Hong

2015-06-01

A superhydrophobic surface was obtained on a low-density polyethylene (LDPE) substrate using a facile method. The water contact angle and the sliding angle of the superhydrophobic LDPE surface were 155 ± 2° and 4°, respectively. The ice shear stress of the superhydrophobic LDPE surface was 2.08 times smaller than that of the flat LDPE surface. The superhydrophobic surface still showed excellent icephobicity and superhydrophobicity after undergoing a circulatory icing/deicing procedure five times. In addition, water condensation and its effect on the icephobicity of the as-prepared superhydrophobic surface were also studied.

A Method for Determining the Rate of Heat Transfer from a Wing or Streamline Body

NASA Technical Reports Server (NTRS)

Frick, Charles W; Mccullough, George B

1945-01-01

A method for calculating the rate of heat transfer from the surface of an airfoil or streamline body is presented. A comparison with the results of an experimental investigation indicates that the accuracy of the method is good. This method may be used to calculate the heat supply necessary for heat de-icing or in ascertaining the heat loss from the fuselage of an aircraft operating at great altitude. To illustrate the method, the total rate of heat transfer from an airfoil is calculated and compared with the experimental results.

Thermal properties of alkali-activated aluminosilicates

NASA Astrophysics Data System (ADS)

Florian, Pavel; Valentova, Katerina; Fiala, Lukas; Zmeskal, Oldrich

2017-07-01

The paper is focused on measurements and evaluation of thermal properties of alkali-activated aluminosilicates (AAA) with various carbon admixtures. Such composites consisting of blast-furnace slag, quartz sand, water glass as alkali activator and small amount of electrically conductive carbon admixture exhibit better electric and thermal properties than the reference material. Such enhancement opens up new practical applications, such as designing of snow-melting, de-icing or self-sensing systems that do not need any external sensors to detect current condition of building material. Thermal properties of the studied materials were measured by the step-wise transient method and mutually compared.

Design, fabrication, and testing of an ultrasonic de-icing system for helicopter rotor blades

NASA Astrophysics Data System (ADS)

Palacios, Jose Luis

A low-power, non-thermal ultrasonic de-icing system is introduced as a possible substitute for current electro-thermal systems. The system generates delaminating ultrasonic transverse shear stresses at the interface of accreted ice. A PZT-4 disk driven at 28.5 KHz (radial resonance of the disk) instantaneously de-bonds 2 mm thick freezer ice layers. The ice layers are accreted to a 0.7 mm thick, 30.4 cm x 30.4 cm steel plate at an environment temperature of -20°C. A power input of 50 Watts is applied to the actuator (50 V, 19.6 KV/m), which translates to a de-icing power of 0.07 W/cm2. A finite element model of the actuator bonded to the isotropic plate is used to guide the design of the system, and predicts the transverse shear stresses at the ice interface. Wind tunnel icing tests were conducted to demonstrate the potential use of the proposed system under impact icing conditions. Both glaze ice and rime ice were generated on steel and composite plates by changing the cloud conditions of the wind tunnel. Continuous ultrasonic vibration prevented impact ice formation around the actuator location at an input power not exceeding 0.18 W/cm 2 (1.2 W/in2). As ice thickness reached a critical thickness of approximately 1.2 mm, shedding occurred on those locations where ultrasonic transverse shear stresses exceeded the shear adhesion strength of the ice. Finite element transverse shear stress predictions correlate with observed experimental impact ice de-bonding behavior. To increase the traveling distance of propagating ultrasonic waves, ultrasonic shear horizontal wave modes are studied. Wave modes providing large modal interface transverse shear stress concentration coefficients (ISCC) between the host structure (0.7 mm thick steel plate) and accreted ice (2.5 mm thick ice layer) are identified and investigated for a potential increase in the wave propagation distance. Ultrasonic actuators able to trigger these optimum wave modes are designed and fabricated. Despite exciting wave modes with high ISCC values, instantaneous ice de-bonding is not observed at input powers under 100 Watts. The two triggered ultrasonic wave modes of the structure occur at high excitation frequencies, 202 KHz and 500 KHz respectively. At these frequencies, the ultrasonic actuators do not provide large enough transverse shear stresses to exceed the shear adhesion strength of the ice layer. Neither the actuator exciting the SH1 mode (202 KHz), nor the actuator triggering the SH2 mode (500 KHz) instantaneously de-bonds ice layers with an input power under 100 Watts.

Numerical Simulation of the Freeze-Thaw Behavior of Mortar Containing Deicing Salt Solution

PubMed Central

Esmaeeli, Hadi S.; Farnam, Yaghoob; Bentz, Dale P.; Zavattieri, Pablo D.; Weiss, Jason

2016-01-01

This paper presents a one-dimensional finite difference model that is developed to describe the freeze-thaw behavior of an air-entrained mortar containing deicing salt solution. A phenomenological model is used to predict the temperature and the heat flow for mortar specimens during cooling and heating. Phase transformations associated with the freezing/melting of water/ice or transition of the eutectic solution from liquid to solid are included in this phenomenological model. The lever rule is used to calculate the quantity of solution that undergoes the phase transformation, thereby simulating the energy released/absorbed during phase transformation. Undercooling and pore size effects are considered in the numerical model. To investigate the effect of pore size distribution, this distribution is considered using the Gibbs-Thomson equation in a saturated mortar specimen. For an air-entrained mortar, the impact of considering pore size (and curvature) on freezing was relatively insignificant; however the impact of pore size is much more significant during melting. The fluid inside pores smaller than 5 nm (i.e., gel pores) has a relatively small contribution in the macroscopic freeze-thaw behavior of mortar specimens within the temperature range used in this study (i.e., +24 °C to −35 °C), and can therefore be neglected for the macroscopic freeze-thaw simulations. A heat sink term is utilized to simulate the heat dissipation during phase transformations. Data from experiments performed using a low-temperature longitudinal guarded comparative calorimeter (LGCC) on mortar specimens fully saturated with various concentration NaCl solutions or partially saturated with water is compared to the numerical results and a promising agreement is generally obtained. PMID:28082830

Numerical Simulation of the Freeze-Thaw Behavior of Mortar Containing Deicing Salt Solution.

PubMed

Esmaeeli, Hadi S; Farnam, Yaghoob; Bentz, Dale P; Zavattieri, Pablo D; Weiss, Jason

2017-02-01

This paper presents a one-dimensional finite difference model that is developed to describe the freeze-thaw behavior of an air-entrained mortar containing deicing salt solution. A phenomenological model is used to predict the temperature and the heat flow for mortar specimens during cooling and heating. Phase transformations associated with the freezing/melting of water/ice or transition of the eutectic solution from liquid to solid are included in this phenomenological model. The lever rule is used to calculate the quantity of solution that undergoes the phase transformation, thereby simulating the energy released/absorbed during phase transformation. Undercooling and pore size effects are considered in the numerical model. To investigate the effect of pore size distribution, this distribution is considered using the Gibbs-Thomson equation in a saturated mortar specimen. For an air-entrained mortar, the impact of considering pore size (and curvature) on freezing was relatively insignificant; however the impact of pore size is much more significant during melting. The fluid inside pores smaller than 5 nm (i.e., gel pores) has a relatively small contribution in the macroscopic freeze-thaw behavior of mortar specimens within the temperature range used in this study (i.e., +24 °C to -35 °C), and can therefore be neglected for the macroscopic freeze-thaw simulations. A heat sink term is utilized to simulate the heat dissipation during phase transformations. Data from experiments performed using a low-temperature longitudinal guarded comparative calorimeter (LGCC) on mortar specimens fully saturated with various concentration NaCl solutions or partially saturated with water is compared to the numerical results and a promising agreement is generally obtained.

Moving from Survival to Healthy Survival through Child Health Screening and Early Intervention Services Under Rashtriya Bal Swasthya Karyakram (RBSK).

PubMed

Singh, Arun K; Kumar, Rakesh; Mishra, C K; Khera, Ajay; Srivastava, Anubhav

2015-11-01

For negating the impact of early adversities on the development and ensuring a healthy, dynamic future for all children, Ministry of Health and Family Welfare in 2013 launched a programme for child health screening and early intervention services as Rashtriya Bal Swasthya Karyakram (RBSK) which aims to improve the quality of life with special focus on improving cognition and survival outcomes for "at risk" children. It has a systemic approach of prevention, early identification and management of 30 health conditions distributed under 4Ds: Defects at birth, Diseases, Deficiencies and Developmental delays including Disabilities spread over birth to 18 y of age in a holistic manner. There is a dedicated 4 member Mobile Health team for community screening and a dedicated 14 member team at District Early Intervention Center (DEIC) for comprehensive management. Existing health infrastructure and personnel are also integrated and utilized in this endeavor. Defects at birth are screened at Delivery points, home visits by accredited social health activist (ASHA), Anganwadi centers and at schools. Developmental delays are evaluated at DEIC through a multidisciplinary team with interdisciplinary approach. Five thousand four hundred eighteen dedicated Mobile Health teams have screened a total of 12.19 crore children till Dec.14. From April to Dec. 2014, 4.20 crore children were screened, of which birth to 6-y-old children were 2.13 crore while 2.07 crore were from 6 to 18 y. 17.7 lakh children were referred to tertiary centers and 6.2 lakh availed tertiary care. 50.7 lakhs were found positive for 4Ds; 1.35 lakhs were birth defects. RBSK is a step towards universal health care for free assured services.

Factors affecting water quality and net flux of solutes in two stream basins in the Quabbin Reservoir drainage basin, central Massachusetts,1983-85

USGS Publications Warehouse

Rittmaster, R.L.; Shanley, J.B.

1995-01-01

The factors that affect stream-water quality were studied at West Branch Swift River (Swift River), and East Branch Fever Brook (Fever Brook), two forested watersheds that drain into the Quabbin Reservoir, central Massachusetts, from December 1983 through August 1985. Spatial and temporal variations of chemistry of precipitation, surface water; and ground water and the linkages between chemical changes and hydrologic processes were used to identify the mechanisms that control stream chemistry. Precipitation chemistry was dominated by hydrogen ion (composite p.H 4.23), sulfate, and nitrate. Inputs of hydrogen and nitrate from pre- cipitation were almost entirely retained in the basins, whereas input of sulfate was approximately balanced by export by streamflow draining the basins. Both streams were poorly buffered, with mean pH near 5.7, mean alkalinity less than 30 microequivalents per liter, and sulfate concen- trations greater than 130 microequivalents per liter. Sodium and chloride, derived primarily from highway deicing salts, were the dominant solutes at Fever Brook. After adjustments for deicing salts, fluxes of base cations during the 21-month study were 2,014 and 1,429 equivalents per hectare in Swift River and Fever Brook, respectively. Base cation fluxes were controlled primarily by weathering of hornblende (Fever Brook) and plagioclase (Swift River). The overall weathering rate was greater in the Swift River Basin because easily weathered gabbro underlies one subbasin which comprises 11.2 percent of the total basin area but contributed about 77 percent of the total alkalinity. Alkalinity export was nearly equal in the two basins, however, because some alkalinity was generated in wetlands in the Fever Brook Basin through bacterial sulfate reduction coupled with organic-carbon oxidation.

Fabrication and Synthesis of Highly Ordered Nickel Cobalt Sulfide Nanowire-Grown Woven Kevlar Fiber/Reduced Graphene Oxide/Polyester Composites.

PubMed

Hazarika, Ankita; Deka, Biplab K; Kim, DoYoung; Roh, Hyung Doh; Park, Young-Bin; Park, Hyung Wook

2017-10-18

Well-aligned NiCo 2 S 4 nanowires, synthesized hydrothermally on the surface of woven Kevlar fiber (WKF), were used to fabricate composites with reduced graphene oxide (rGO) dispersed in polyester resin (PES) by means of vacuum-assisted resin transfer molding. The NiCo 2 S 4 nanowires were synthesized with three precursor concentrations. Nanowire growth was characterized using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Hierarchical and high growth density of the nanowires led to exceptional mechanical properties of the composites. Compared with bare WKF/PES, the tensile strength and absorbed impact energy were enhanced by 96.2% and 92.3%, respectively, for WKF/NiCo 2 S 4 /rGO (1.5%)/PES. The synergistic effect of NiCo 2 S 4 nanowires and rGO in the fabricated composites improved the electrical conductivity of insulating WKF/PES composites, reducing the resistance to ∼10 3 Ω. Joule heating performance depended strongly on the precursor concentration of the nanowires and the presence of rGO in the composite. A maximum surface temperature of 163 °C was obtained under low-voltage (5 V) application. The Joule heating performance of the composites was demonstrated in a surface deicing experiment; we observed that 17 g of ice melted from the surface of the composite in 14 min under an applied voltage of 5 V at -28 °C. The excellent performance of WKF/NiCo 2 S 4 /rGO/PES composites shows great potential for aerospace structural applications requiring outstanding mechanical properties and Joule heating capability for deicing of surfaces.

Results of low power deicer tests on a swept inlet component in the NASA Lewis icing research tunnel

NASA Technical Reports Server (NTRS)

Bond, Thomas H.; Shin, Jaiwon

1993-01-01

Tests were conducted under a USAF/NASA Low Power Deicer program on two expulsive technologies to examine system performance on hardware representative of a modern aircraft part. The BF Goodrich Electro-Expulsive Deicing System and Pneumatic Impulse Ice Protection System were installed on a swept, compound curve, engine inlet component with varying leading edge radius, and tested through a range of icing and system operating conditions in the NASA Lewis Icing Research Tunnel. A description of the experimental procedure and results, including residual ice thickness, shed ice particle size, and changes in system energy/pressure characteristics are presented.

Results of Low Power Deicer tests on a swept inlet component in the NASA Lewis Icing Research Tunnel

NASA Technical Reports Server (NTRS)

Bond, Thomas H.; Shin, Jaiwon

1993-01-01

Tests were conducted under a USAF/NASA Low Power Deicer program on two expulsive technologies to examine system performance on hardware representative of a modern aircraft part. The BF Goodrich Electro-Expulsive Deicing System and Pneumatic Impulse Ice Protection system were installed on a swept, compound curve, engine inlet component with varying leading edge radius, and tested through a range of icing and system operating conditions in the NASA Lewis Icing Research Tunnel. A description of the experimental procedure and results, including residual ice thickness, shed ice particle size, and changes in system energy/pressure characteristics are presented.

Electric Ground Support Equipment at Airports

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-12-12

Airport ground support equipment (GSE) is used to service airplanes between flights. Services include refueling, towing airplanes or luggage/freight carts, loading luggage/freight, transporting passengers, loading potable water, removing sewage, loading food, de-icing airplanes, and fire-fighting. Deploying new GSE technologies is a promising opportunity in part because the purchasers are generally large, technologically sophisticated airlines, contractors, or airports with centralized procurement and maintenance departments. Airlines could particularly benefit from fuel diversification since they are highly exposed to petroleum price volatility. GSE can be particularly well-suited for electrification because it benefits from low-end torque and has frequent idle time and short requiredmore » ranges.« less

Nutrient, organic carbon, and chloride concentrations and loads in selected Long Island Sound tributaries—Four decades of change following the passage of the Federal Clean Water Act

USGS Publications Warehouse

Mullaney, John R.

2016-03-10

Loads of dissolved silica (DSi; flow-normalized and non-flow-normalized) increased slightly at most stations during the study period and were positively correlated to urbanized land in the basin and negatively correlated to area of open water. Concentrations and loads of chloride increased at 12 of the 14 sites during both periods. Increases likely are the result of an increase in the use of salt for deicing, as well as other factors related to urbanization and population growth, such as increases in wastewater discharge and discharge from septic systems.

Highway pavement performance test for colored thin anti-skidding layers

NASA Astrophysics Data System (ADS)

Gao, Wei; Cui, Wei; Xu, Ming

2018-03-01

Based on the actual service condition of highway pavement colored thin anti-skidding layers, with materials of color quartz sand and two-component acrylic resin as basis, we designed such tests as the bond strength, shearing strength, tear strength, fatigue performance and aggregate polished value, and included the freeze-thaw cycle and de-icing salt and other factors in the experiment, connecting with the climate characteristics of circumpolar latitude and low altitude in Heilongjiang province. Through the pavement performance test, it is confirmed that the colored thin anti-skidding layers can adapt to cold and humid climate conditions, and its physical mechanical properties are good.

CLEAN-ROADS project: air quality considerations after the application of a novel MDSS on winter road maintenance activities

NASA Astrophysics Data System (ADS)

Pretto, Ilaria; Malloci, Elisa; Tonidandel, Gabriele; Benedetti, Guido; Di Napoli, Claudia; Piazza, Andrea; Apolloni, Roberto; Cavaliere, Roberto

2016-04-01

With this poster we present the environmental benefit on air quality derived by the application of the CLEAN-ROADS pilot project. The CLEAN-ROADS project addresses the problem of the environmental pollution caused by de-icing salts during winter road maintenance activities in the Province of Trento (Italy). A demonstrative Maintenance Decision Support System (MDSS) has been developed in order to improve the intervention procedures of the road management service. Specifically it aims to optimize the efficiency of how available resources (e.g., salt consumption) are currently used while guaranteeing the current level of road safety. The CLEAN-ROADS project has been tested and validated on a test area located in a valley bottom (Adige Valley), where the highest optimization margins are to be expected. The project supports current road maintenance practices, which has proved to be reliable and accurate, with a new scalable and energy-efficient road monitoring system. This system is based on a network of road weather stations (road weather information system, RWIS) installed on the test route. It is capable to collect real-time data about the road conditions and to perform short-term and now-cast road weather forecasts, which actively integrate weather data and bulletins covering the target area [1]. This poster presents the results obtained from a three-year monitoring activity with the aim to (1) determine the impact of de-icing salts on air quality and (2) quantify the improvements obtained by the application of the CLEAN-ROADS project on air quality. The Ambient Air Quality and Cleaner Air for Europe Directive (2008/50/EC) states that contributions to exceedances of particulate matter PM10 limit values that are attributable to road winter salting may be subtracted when assessing compliance with air quality limit values, once provided that reasonable measures have been taken to lower concentrations [2]. As the de-icing salts used in road maintenance are mainly based on sodium chloride, which releases Na+ and Cl-, the estimation of the contribution of road salting to PM10 concentration can be carried out considering only measured concentrations of Na+ and Cl-. However, the presence of these elements might not be due exclusively to salting activities. For this reason data collected during first winter campaign were analysed using the Positive Matrix Factorization (PMF) Model developed by United States Environmental Protection Agency (EPA) to identify the presence of Na+ and Cl- in emission profiles of other PM10 sources (e.g., biomass burning, traffic) [3]. Through this study new guidelines have been defined for the optimization of current road management operations, and their applicability to other area in the Province of Trento has been assessed for future purposes. [1] Pretto I. et al., SIRWEC 2014 conference proceedings, ID:0019 (2014) [2] Ambient Air Quality and Cleaner Air for Europe (CAFE) Directive (2008/50/EC) [3] http://www.epa.gov/air-research/positive-matrix-factorization-model-environmental-data-analyses

Evaluation of a pneumatic boot deicing system on a general aviation wing model

NASA Technical Reports Server (NTRS)

Albright, A. E.; Kohlman, D. L.; Schweikhard, W. G.; Evanich, P.

1981-01-01

The aerodynamic characteristics of a typical modern general aviation airfoil were investigated with and without a pneumatic boot ice protection system. The ice protection effectiveness of the boot was studied. This includes the change in drag on the airfoil with the boot inflated and deflated, the change in drag due to primary and residual ice formation, drag change due to cumulative residual ice formation, and parameters affecting boot effectiveness. Boot performance was not affected by tunnel total temperature or velocity. Marginal effect in performance was associated with angle of attack. Significant effects on performance were caused by variations in droplet size, LWC, ice cap thickness inflation pressure, and surface treatment.

Use of borehole and surface geophysics to investigate ground-water quality near a road-deicing salt-storage facility, Valparaiso, Indiana

USGS Publications Warehouse

Risch, M.R.; Robinson, B.A.

2001-01-01

Two surface surveys of terrain electromagnetic conductivity were used to map the horizontal extent of the saltwater plume in areas without monitoring wells. Background values of terrain conductivity were measured in an area where water-quality and borehole geophysical data did not indicate saline or brackish water. Based on a guideline from previous case studies, the boundaries of the saltwater plume were mapped where terrain conductivity was 1.5 times background. The extent of the saltwater plume, based on terrain conductivity, generally was consistent with the available water-quality and borehole electromagnetic-conductivity data and with directions of ground-water flow determined from water-level altitudes.

Theoretical and practical aspects of improving the durability of steel reinforcement in transport designs, using passivation and plasticizing chemical additives

NASA Astrophysics Data System (ADS)

Velichko, Evgenij; Talipov, Linar

2017-10-01

The article deals with the problem of steel reinforcement corrosion in reinforced concrete structures exposed to aggressive media, in particular in reinforced concrete construction of transport infrastructure, in snowy areas, and subject to the influence of chlorides contained in applied deicing agents. Basic schemes for preventing the reinforcement corrosion in reinforced-concrete structures have been considered and analyzed. Prospects of primary protection against corrosion of reinforcement by introducing chemical additives with plasticizing/passivating action in a concrete mixture with mixing water have been considered in detail. The physical/chemical mechanism of the protective action of a superplasticizer together with a passivator has been highlighted.

A comparison of numerical methods for the prediction of two-dimensional heat transfer in an electrothermal deicer pad. M.S. Thesis. Final Contractor Report

NASA Technical Reports Server (NTRS)

Wright, William B.

1988-01-01

Transient, numerical simulations of the deicing of composite aircraft components by electrothermal heating have been performed in a 2-D rectangular geometry. Seven numerical schemes and four solution methods were used to find the most efficient numerical procedure for this problem. The phase change in the ice was simulated using the Enthalpy method along with the Method for Assumed States. Numerical solutions illustrating deicer performance for various conditions are presented. Comparisons are made with previous numerical models and with experimental data. The simulation can also be used to solve a variety of other heat conduction problems involving composite bodies.

Experimental and finite element analyses of multifunctional skins for morphing wing applications

NASA Astrophysics Data System (ADS)

Geier, Sebastian; Kintscher, Markus; Mahrholz, Thorsten; Wierach, Peter; Monner, Hans-Peter; Wiedemann, Martin

2016-04-01

As a consequence of operational efficiency because of rising energy costs, future transport systems need to be mission-adaptive. Especially in aircraft design the limits of lightweight construction, reduced aerodynamic drag and optimized propulsion are pushed further and further. The first two aspects can be addressed by using a morphing leading edge. Great economic advantages can be expected as a result of gapless surfaces which feature longer areas of laminar flow. Instead of focusing on the kinematics, which are already published in a great number of varieties, this paper emphasizes as major challenge, the qualification of a multi-material layup which meets the compromise of needed stiffness, flexibility and essential functions to match the flight worthiness requirements, such as erosion shielding, impact safety, lighting protection and de-icing. It is the aim to develop an gapless leading edge device and to prepare the path for higher technology readiness levels resulting in an airborne application. During several national and European projects the DLR developed a gapless smart droop nose concept, which functionality was successfully demonstrated using a two-dimensional 5 m in span prototype in low speed (up to 50 m/s) wind tunnel tests. The basic structure is made of commercially available and certified glass-fiber reinforced plastics (GFRP, Hexcel Hexply 913). This paper presents 4-point bending tests to characterize the composite with its integrated functions. The integrity and aging/fatigue issues of different material combinations are analyzed by experiments. It can be demonstrated that only by adding functional layers the mentioned requirements such as erosion-shielding or de-icing can be satisfied. The total thickness of the composite skin increases by more than 100 % when required functions are integrated as additional layers. This fact has a tremendous impact on the maximum strain of the outer surface if it features a complete monolithic build-up. Based on experimental results a numerical model can be set up for further structural optimizaton of the multi-functional laminate.

Salinization triggers a trophic cascade in experimental freshwater communities with varying food-chain length.

PubMed

Hintz, William D; Mattes, Brian M; Schuler, Matthew S; Jones, Devin K; Stoler, Aaron B; Lind, Lovisa; Relyea, Rick A

2017-04-01

The application of road deicing salts in northern regions worldwide is changing the chemical environment of freshwater ecosystems. Chloride levels in many lakes, streams, and wetlands exceed the chronic and acute thresholds established by the United States and Canada for the protection of freshwater biota. Few studies have identified the impacts of deicing salts in stream and wetland communities and none have examined impacts in lake communities. We tested how relevant concentrations of road salt (15, 100, 250, 500, and 1000 mg Cl - /L) interacted with experimental communities containing two or three trophic levels (i.e., no fish vs. predatory fish). We hypothesized that road salt and fish would have a negative synergistic effect on zooplankton, which would then induce a trophic cascade. We tested this hypothesis in outdoor mesocosms containing filamentous algae, periphyton, phytoplankton, zooplankton, several macroinvertebrate species, and fish. We found that the presence of fish and high salt had a negative synergistic effect on the zooplankton community, which in turn caused an increase in phytoplankton. Contributing to the magnitude of this trophic cascade was a direct positive effect of high salinity on phytoplankton abundance. Cascading effects were limited with respect to impacts on the benthic food web. Periphyton and snail grazers were unaffected by the salt-induced trophic cascade, but the biomass of filamentous algae decreased as a result of competition with phytoplankton for light or nutrients. We also found direct negative effects of high salinity on the biomass of filamentous algae and amphipods (Hyalella azteca) and the mortality of banded mystery snails (Viviparus georgianus) and fingernail clams (Sphaerium simile). Clam mortality was dependent on the presence of fish, suggesting a non-consumptive interactive effect with salt. Our results indicate that globally increasing concentrations of road salt can alter community structure via both direct and indirect effects. © 2016 by the Ecological Society of America.

Validation of NASA Thermal Ice Protection Computer Codes. Part 3; The Validation of Antice

NASA Technical Reports Server (NTRS)

Al-Khalil, Kamel M.; Horvath, Charles; Miller, Dean R.; Wright, William B.

2001-01-01

An experimental program was generated by the Icing Technology Branch at NASA Glenn Research Center to validate two ice protection simulation codes: (1) LEWICE/Thermal for transient electrothermal de-icing and anti-icing simulations, and (2) ANTICE for steady state hot gas and electrothermal anti-icing simulations. An electrothermal ice protection system was designed and constructed integral to a 36 inch chord NACA0012 airfoil. The model was fully instrumented with thermo-couples, RTD'S, and heat flux gages. Tests were conducted at several icing environmental conditions during a two week period at the NASA Glenn Icing Research Tunnel. Experimental results of running-wet and evaporative cases were compared to the ANTICE computer code predictions and are presented in this paper.

Radome having integral heating and impedance matching elements

NASA Astrophysics Data System (ADS)

Lopez, Alfred R.

1992-04-01

An antenna radome includes a dielectric member shaped to protect an antenna from environmental conditions, and a plurality of conductors fixed in relation to a major surface of the dielectric member in a predetermined pattern so that the member with the conductors provides a lower reflection coefficient to incident electromagnetic waves at the operating wavelength of the antenna than in the absence of the conductors. Means are provided for causing a desired heating current to flow through the conductors, thereby enabling sufficient heat to be generated in the dielectric member to de-ice the radome during severe weather conditions. A specific embodiment of the radome of the invention is described for use with an antenna of the type used in a microwave landing system.

Experimental study and numerical simulation of the salinity effect on water-freezing point and ice-melting rate

NASA Astrophysics Data System (ADS)

Qin, N.; Wu, Y.; Wang, H. W.; Wang, Y. Y.

2017-12-01

In this paper, based on the background of snowmelt de-icing tools, we studied the effect of salt on freezing point and melting rate of ice through laboratory test and FLUENT numerical simulation analysis. It was confirmed that the freezing point is inversely proportional to the salt solid content, and with the salt solid content increasing, the freezing process of salt water gradually accepts the curing rule of non-crystal solids. At the same temperature, an increase in the salt solid content, the ice melting rate increase by the empirical formula linking the melting time with temperature and salt content. The theoretical aspects of solid/fluid transformation are discussed in detail.

Saccharide antifreeze compositions

DOEpatents

Walters, Kent; Duman, John G; Serianni, Anthony S

2013-12-10

The invention provides an antifreeze glycolipid compounds and composition comprising a polysaccharide moiety of Formula I; ##STR00001## wherein D-Manp represents a D-mannopyranose moiety, D-Xylp represents a D-xylopyranose moiety, and n is about 5 to about 70; and one or more lipid moieties covalently linked to the polysaccharide moiety of Formula I or electrostatically associated with the polysaccaride moiety for Formula I. The antifreeze glycolipid compounds and compositions can be used for a variety of industrial, agricultural, medical, and cosmetic applications where recrystallization-inhibition, cyroprotection, or cryopreservation is desired. The antifreeze glycolipid compounds or compositions can be used as, for example, as cryoprotectants for tissue preservation and transplantation, improving the texture of processed frozen food and frozen meats, frostbit protection, crop protection, and green alternatives for land vehicle antifreeze and aircraft de-icing.

Numerical simulation of an electrothermal deicer pad. M.S. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Marano, J. J.

1983-01-01

A numerical simulation is developed to investigate the removal of ice from composite aircraft blades by means of electrothermal deicing. The model considers one dimensional, unsteady state heat transfer in the composite blade-ice body. The heat conduction equations are approximated by using the Crank-Nicolson finite difference scheme, and the phase change in the ice layer is handled using the Enthalpy method. To solve the system of equations which result, Gauss-Seidel iteration is used. The simulation computes the temperature profile in the composite blade-ice body, as well as the movement of the ice-water interface, as a function of time. This information can be used to evaluate deicer performance. The simulation can also be used to solve a variety of other heat conduction problems involving composite bodies.

Macroscopic and mesoscopic approach to the alkali-silica reaction in concrete

NASA Astrophysics Data System (ADS)

Grymin, Witold; Koniorczyk, Marcin; Pesavento, Francesco; Gawin, Dariusz

2018-01-01

A model of the alkali-silica reaction, which takes into account couplings between thermal, hygral, mechanical and chemical phenomena in concrete, has been discussed. The ASR may be considered at macroscopic or mesoscopic scale. The main features of each approach have been summarized and development of the model for both scales has been briefly described. Application of the model to experimental results for both scales has been presented. Even though good accordance of the model has been obtained for both approaches, consideration of the model at the mesoscopic scale allows to model different mortar mixes, prepared with the same aggregate, but of different grain size, using the same set of parameters. It enables also to predict reaction development assuming different alkali sources, such as de-icing salts or alkali leaching.

Nowcasting for a high-resolution weather radar network

NASA Astrophysics Data System (ADS)

Ruzanski, Evan

Short-term prediction (nowcasting) of high-impact weather events can lead to significant improvement in warnings and advisories and is of great practical importance. Nowcasting using weather radar reflectivity data has been shown to be particularly useful. The Collaborative Adaptive Sensing of the Atmosphere (CASA) radar network provides high-resolution reflectivity data amenable to producing valuable nowcasts. The high-resolution nature of CASA data requires the use of an efficient nowcasting approach, which necessitated the development of the Dynamic Adaptive Radar Tracking of Storms (DARTS) and sinc kernel-based advection nowcasting methodology. This methodology was implemented operationally in the CASA Distributed Collaborative Adaptive Sensing (DCAS) system in a robust and efficient manner necessitated by the high-resolution nature of CASA data and distributed nature of the environment in which the nowcasting system operates. Nowcasts up to 10 min to support emergency manager decision-making and 1--5 min to steer the CASA radar nodes to better observe the advecting storm patterns for forecasters and researchers are currently provided by this system. Results of nowcasting performance during the 2009 CASA IP experiment are presented. Additionally, currently state-of-the-art scale-based filtering methods were adapted and evaluated for use in the CASA DCAS to provide a scale-based analysis of nowcasting. DARTS was also incorporated in the Weather Support to Deicing Decision Making system to provide more accurate and efficient snow water equivalent nowcasts for aircraft deicing decision support relative to the radar-based nowcasting method currently used in the operational system. Results of an evaluation using data collected from 2007--2008 by the Weather Service Radar-1988 Doppler (WSR-88D) located near Denver, Colorado, and the National Center for Atmospheric Research Marshall Test Site near Boulder, Colorado, are presented. DARTS was also used to study the short-term predictability of precipitation patterns depicted by high-resolution reflectivity data observed at microalpha (0.2--2 km) to mesobeta (20--200 km) scales by the CASA radar network. Additionally, DARTS was used to investigate the performance of nowcasting rainfall fields derived from specific differential phase estimates, which have been shown to provide more accurate and robust rainfall estimates compared to those made from radar reflectivity data.

Monitoring snowmelt and solute transport at Oslo airport by combining time-lapse electrical resistivity, soil water sampling and tensiometer measurements

NASA Astrophysics Data System (ADS)

Bloem, E.; French, H. K.

2013-12-01

Monitoring contaminant transport at contaminated sites requires optimization of the configuration of a limited number of samplings points combined with heterogeneous flow and preferential flowpaths. Especially monitoring processes in the unsaturated zone is a major challenge due to the limited volume monitored by for example suction cups and their risk to clog in a highly active degradation zone. To make progress on soil contamination assessment and site characterization there is a strong need to integrate field-sale extensively instrumented tools, with non-invasive (geophysical) methods which provide spatially integrated measurements also in the unsaturated zone. Examples of sites that might require monitoring activities in the unsaturated zone are airports with winter frost where large quantities of de-icing chemicals are used each winter; salt and contaminant infiltration along roads; constructed infiltration systems for treatment of sewerage or landfill seepage. Electrical resistivity methods have proved to be useful as an indirect measurement of subsurface properties and processes at the field-scale. The non-uniqueness of the interpretation techniques can be reduced by constraining the inversion through the addition of independent geophysical measurements along the same profile. Or interpretation and understanding of geophysical images can be improved by the combination with classical measurements of soil physical properties, soil suction, contaminant concentration and temperatures. In our experiment, at the research field station at Gardermoen, Oslo airport, we applied a degradable de-icing chemical and an inactive tracer to the snow cover prior to snowmelt. To study the solute transport processes in the unsaturated zone time-lapse cross borehole electrical resistivity tomography (ERT) measurements were conducted at the same time as soil water samples were extracted at multiple depths with suction cups. Measurements of soil temperature, and soil tension were also carried out during the monitoring period. We present a selection of results from the snowmelt experiments and how the combination of measurement techniques can help interpret and understand the relative importance of the various contributions to the bulk electrical conductivity during snowmelt and solute transport.

Laboratory Investigation of Ice Formation and Elimination in the Induction System of a Large Twin-engine Cargo Aircraft

NASA Technical Reports Server (NTRS)

Colis, William D

1947-01-01

The icing characteristics, the de-icing rate with hot air, and the effect of impact ice on fuel metering and mixture distribution have been determined in a laboratory investigation of that part of the engine induction system consisting of a three-barrel injection-type carburetor and a supercharger housing with spinner-type fuel injection from an 18-cylinder radial engine used on a large twin-engine cargo airplane. The induction system remained ice-free at carburetor-air temperatures above 36 F regardless of the moisture content of the air. Between carburetor-air temperatures of 32 F and 36 F with humidity ratios in excess of saturation, serious throttling ice formed in the carburetor because of expansion cooling of the air; at carburetor-air temperatures below 32 F with humidity ratios in excess of saturation, serious impact-ice formations occurred, Spinner-type fuel injection at the entrance to the supercharger and heating of the supercharger-inlet elbow and the guide vanes by the warn oil in the rear engine housing are design features that proved effective in eliminating fuel-evaporation icing and minimized the formation of throttling ice below the carburetor. Air-flow recovery time with fixed throttle was rapidly reduced as the inlet -air wet -bulb temperature was increased to 55 F; further temperature increase produced negligible improvement in recovery time. Larger ice formations and lower icing temperatures increased the time required to restore proper air flow at a given wet-bulb temperature. Impact-ice formations on the entrance screen and the top of the carburetor reduced the over-all fuel-air ratio and increased the spread between the over-all ratio and the fuel-air ratio of the individual cylinders. The normal spread of fuel-air ratio was increased from 0.020 to 0.028 when the left quarter of the entrance screen was blocked in a manner simulating the blocking resulting from ice formations released from upstream duct walls during hot-air de-icing.

Method and apparatus for acoustic plate mode liquid-solid phase transition detection

DOEpatents

Blair, Dianna S.; Freye, Gregory C.; Hughes, Robert C.; Martin, Stephen J.; Ricco, Antonio J.

1993-01-01

A method and apparatus for sensing a liquid-solid phase transition event is provided which comprises an acoustic plate mode detecting element placed in contact with a liquid or solid material which generates a high-frequency acoustic wave that is attenuated to an extent based on the physical state of the material is contact with the detecting element. The attenuation caused by the material in contact with the acoustic plate mode detecting element is used to determine the physical state of the material being detected. The method and device are particularly suited for detecting conditions such as the icing and deicing of wings of an aircraft. In another aspect of the present invention, a method is provided wherein the adhesion of a solid material to the detecting element can be measured using the apparatus of the invention.

Dynamics of Phase Transitions in a Snow Mass Containing Water-Soluble Salt Particles

NASA Astrophysics Data System (ADS)

Zelenko, V. L.; Heifets, L. I.; Orlov, Yu. N.; Voskresenskiy, N. M.

2018-07-01

A macrokinetic approach is used to describe the dynamics of phase transitions in a snow mass containing water-soluble salt particles. Equations are derived that describe the rate of salt granule dissolution and the change in the phase composition and temperature of a snow mass under the conditions of heat transfer with an isothermal surface. An experimental setup that models the change in the state of a snow mass placed on an isothermal surface is created to verify theoretical conclusions. Experimental observations of the change in temperature of the snow mass are compared to theoretical calculations. The mathematical model that is developed can be used to predict the state of a snow mass on roads treated with a deicing agent, or to analyze the state of snow masses containing water-soluble salt inclusions and resting on mountain slopes.

Predicted and measured transmission and diffraction by a metallic mesh coating

NASA Astrophysics Data System (ADS)

Halman, Jennifer I.; Ramsey, Keith A.; Thomas, Michael; Griffin, Andrew

2009-05-01

Metallic mesh coatings are used on visible and infrared windows and domes to provide shielding from electromagnetic interference (EMI) and as heaters to de-fog or de-ice windows or domes. The periodic metallic mesh structures that provide the EMI shielding and/or resistive electrical paths for the heating elements create a diffraction pattern when optical or infrared beams are incident on the coated windows. Over the years several different mesh geometries have been used to try to reduce the effects of diffraction. We have fabricated several different mesh patterns on small coupons of BK-7 and measured the transmitted power and the diffraction patterns of each one using a CW 1064 nm laser. In this paper we will present some predictions and measurements of the diffraction patterns of several different mesh patterns.

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals.

PubMed

Repetto, Sonia L; Costello, James F; Butts, Craig P; Lam, Joseph K W; Ratcliffe, Norman M

2016-01-01

A novel approach to protecting jet fuel against the effects of water contamination is predicated upon the coupling of the rapid hydrolysis reactions of lipophilic cyclic geminal ethers, with the concomitant production of a hydrophilic acyclic hydroxyester with de-icing properties (Fuel Dehydrating Icing Inhibitors - FDII). To this end, a kinetic appraisal of the hydrolysis reactions of representative geminal ethers was undertaken using a convenient surrogate for the fuel-water interface (D2O/CD3CN 1:4). We present here a library of acyclic and five/six-membered cyclic geminal ethers arranged according to their hydroxonium catalytic coefficients for hydrolysis, providing for the first time a framework for the development of FDII. A combination of (1)H NMR, labelling and computational studies was used to assess the effects that may govern the observed relative rates of hydrolyses.

Advanced ice protection systems test in the NASA Lewis icing research tunnel

NASA Technical Reports Server (NTRS)

Bond, Thomas H.; Shin, Jaiwon; Mesander, Geert A.

1991-01-01

Tests of eight different deicing systems based on variations of three different technologies were conducted in the NASA Lewis Research Center Icing Research Tunnel (IRT) in June and July 1990. The systems used pneumatic, eddy current repulsive, and electro-expulsive means to shed ice. The tests were conducted on a 1.83 m span, 0.53 m chord NACA 0012 airfoil operated at a 4 degree angle of attack. The models were tested at two temperatures: a glaze condition at minus 3.9 C and a rime condition at minus 17.2 C. The systems were tested through a range of icing spray times and cycling rates. Characterization of the deicers was accomplished by monitoring power consumption, ice shed particle size, and residual ice. High speed video motion analysis was performed to quantify ice particle size.

Aircraft and Ground Vehicle Winter Runway Friction Assessment

NASA Technical Reports Server (NTRS)

Yager, Thomas J.

1999-01-01

Some background information is given together with the scope and objectives of a 5-year, Joint Winter Runway Friction Measurement Program between the National Aeronautics & Space Administration (NASA), Transport Canada (TC), and the Federal Aviation Administration (FAA). The primary objective of this effort is to perform instrumented aircraft and ground vehicle tests aimed at identifying a common number that all the different ground vehicle devices would report. This number, denoted the International Runway Friction Index (IRFI), will be related to all types of aircraft stopping performance. The range of test equipment, the test sites, test results and accomplishments, the extent of the substantial friction database compiled, and future test plans will be described. Several related studies have also been implemented including the effects of contaminant type on aircraft impingement drag, and the effectiveness of various runway and aircraft de-icing chemical types, and application rates.

Solar Thermal Energy Storage Device: Hybrid Nanostructures for High-Energy-Density Solar Thermal Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2012-01-09

HEATS Project: MIT is developing a thermal energy storage device that captures energy from the sun; this energy can be stored and released at a later time when it is needed most. Within the device, the absorption of sunlight causes the solar thermal fuel’s photoactive molecules to change shape, which allows energy to be stored within their chemical bonds. A trigger is applied to release the stored energy as heat, where it can be converted into electricity or used directly as heat. The molecules would then revert to their original shape, and can be recharged using sunlight to begin themore » process anew. MIT’s technology would be 100% renewable, rechargeable like a battery, and emissions-free. Devices using these solar thermal fuels—called Hybrisol—can also be used without a grid infrastructure for applications such as de-icing, heating, cooking, and water purification.« less

Biodegradation of propylene glycol and associated hydrodynamic effects in sand.

PubMed

Bielefeldt, Angela R; Illangasekare, Tissa; Uttecht, Megan; LaPlante, Rosanna

2002-04-01

At airports around the world, propylene glycol (PG) based fluids are used to de-ice aircraft for safe operation. PG removal was investigated in 15-cm deep saturated sand columns. Greater than 99% PG biodegradation was achieved for all flow rates and loading conditions tested, which decreased the hydraulic conductivity of the sand by 1-3 orders of magnitude until a steady-state minimum was reached. Under constant loading at 120 mg PG/d for 15-30 d, the hydraulic conductivity (K) decreased by 2-2.5 orders of magnitude when the average linear velocity of the water was 4.9-1.4 cm/h. Variable PG loading in recirculation tests resulted in slower conductivity declines and lower final steady-state conductivity than constant PG feeding. After significant sand plugging, endogenous periods of time without PG resulted in significant but partial recovery of the original conductivity. Biomass growth also increased the dispersivity of the sand.

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals

PubMed Central

Repetto, Sonia L; Butts, Craig P; Lam, Joseph K W; Ratcliffe, Norman M

2016-01-01

Summary A novel approach to protecting jet fuel against the effects of water contamination is predicated upon the coupling of the rapid hydrolysis reactions of lipophilic cyclic geminal ethers, with the concomitant production of a hydrophilic acyclic hydroxyester with de-icing properties (Fuel Dehydrating Icing Inhibitors - FDII). To this end, a kinetic appraisal of the hydrolysis reactions of representative geminal ethers was undertaken using a convenient surrogate for the fuel–water interface (D2O/CD3CN 1:4). We present here a library of acyclic and five/six-membered cyclic geminal ethers arranged according to their hydroxonium catalytic coefficients for hydrolysis, providing for the first time a framework for the development of FDII. A combination of 1H NMR, labelling and computational studies was used to assess the effects that may govern the observed relative rates of hydrolyses. PMID:27559399

NASA's program on icing research and technology

NASA Technical Reports Server (NTRS)

Reinmann, John J.; Shaw, Robert J.; Ranaudo, Richard J.

1989-01-01

NASA's program in aircraft icing research and technology is reviewed. The program relies heavily on computer codes and modern applied physics technology in seeking icing solutions on a finer scale than those offered in earlier programs. Three major goals of this program are to offer new approaches to ice protection, to improve our ability to model the response of an aircraft to an icing encounter, and to provide improved techniques and facilities for ground and flight testing. This paper reviews the following program elements: (1) new approaches to ice protection; (2) numerical codes for deicer analysis; (3) measurement and prediction of ice accretion and its effect on aircraft and aircraft components; (4) special wind tunnel test techniques for rotorcraft icing; (5) improvements of icing wind tunnels and research aircraft; (6) ground de-icing fluids used in winter operation; (7) fundamental studies in icing; and (8) droplet sizing instruments for icing clouds.

Numerical simulation of one-dimensional heat transfer in composite bodies with phase change. M.S. Thesis, 1980 Final Report; [wing deicing pads

NASA Technical Reports Server (NTRS)

Dewitt, K. J.; Baliga, G.

1982-01-01

A numerical simulation was developed to investigate the one dimensional heat transfer occurring in a system composed of a layered aircraft blade having an ice deposit on its surface. The finite difference representation of the heat conduction equations was done using the Crank-Nicolson implicit finite difference formulation. The simulation considers uniform or time dependent heat sources, from heaters which can be either point sources or of finite thickness. For the ice water phase change, a numerical method which approximates the latent heat effect by a large heat capacity over a small temperature interval was applied. The simulation describes the temperature profiles within the various layers of the de-icer pad, as well as the movement of the ice water interface. The simulation could also be used to predict the one dimensional temperature profiles in any composite slab having different boundary conditions.

Results of a low power ice protection system test and a new method of imaging data analysis

NASA Technical Reports Server (NTRS)

Shin, Jaiwon; Bond, Thomas H.; Mesander, Geert A.

1992-01-01

Tests were conducted on a BF Goodrich De-Icing System's Pneumatic Impulse Ice Protection (PIIP) system in the NASA Lewis Icing Research Tunnel (IRT). Characterization studies were done on shed ice particle size by changing the input pressure and cycling time of the PIIP de-icer. The shed ice particle size was quantified using a newly developed image software package. The tests were conducted on a 1.83 m (6 ft) span, 0.53 m (221 in) chord NACA 0012 airfoil operated at a 4 degree angle of attack. The IRT test conditions were a -6.7 C (20 F) glaze ice, and a -20 C (-4 F) rime ice. The ice shedding events were recorded with a high speed video system. A detailed description of the image processing package and the results generated from this analytical tool are presented.

Organochlorine compounds and the biogeochemical cycle of chlorine in soils: A review

NASA Astrophysics Data System (ADS)

Vodyanitskii, Yu. N.; Makarov, M. I.

2017-09-01

Chloride ions in soil may interact with soil organic matter and form organochlorine compounds in situ. The biotic chlorination of soil organic substances takes places under aerobic conditions with participation of H2O2 forming from peroxidases released by soil microorganisms (in particular, by microscopic fungi). The abiotic chlorination results also from the redox reactions with the participation of Fe3+/Fe2+ system, but it develops several times slower. Chlorination of soil organic substances is favored by Cl- coming to soil both from natural (salinized soil-forming rocks and groundwater, sea salt) and anthropogenic sources of chlorides, i.e., spills of saline water at oil production, road deicing chemicals, mineral fertilizers, etc. The study of the biogeochemical chlorine cycle should take into account the presence of organochlorine compounds in soils, in addition to transformation and migration of chloride ions.

Influence of De-icers on the Corrosion and Fatigue Behavior of 4140 Steel

NASA Astrophysics Data System (ADS)

Dean, William P.; Sanford, Brittain J.; Wright, Matthew R.; Evans, Jeffrey L.

2012-11-01

The purpose of this test was to evaluate the effects of calcium magnesium acetate (CMA) and sodium chloride (NaCl)—two common substances used to de-ice roadways—on the corrosion and fatigue behavior of annealed AISI 4140 steel. When CMA-corroded, NaCl-corroded, and as-machined samples were tested using R = 0.1, and f = 20 Hz, it was found that, within the scope of this study, samples corroded in both 3.5% CMA solution and 3.5% NaCl solution exhibited a lower fatigue strength than samples tested in the as-machined, uncorroded condition. For the short lives tested in this study, the difference in the effects of CMA and NaCl is minimal. However, at longer lives it is suspected, based on the trends, that the CMA solution would be less detrimental to the fatigue life.

Salinisation of rivers: an urgent ecological issue.

PubMed

Cañedo-Argüelles, Miguel; Kefford, Ben J; Piscart, Christophe; Prat, Narcís; Schäfer, Ralf B; Schulz, Claus-Jürgen

2013-02-01

Secondary salinisation of rivers and streams is a global and growing threat that might be amplified by climate change. It can have many different causes, like irrigation, mining activity or the use of salts as de-icing agents for roads. Freshwater organisms only tolerate certain ranges of water salinity. Therefore secondary salinisation has an impact at the individual, population, community and ecosystem levels, which ultimately leads to a reduction in aquatic biodiversity and compromises the goods and services that rivers and streams provide. Management of secondary salinization should be directed towards integrated catchment strategies (e.g. benefiting from the dilution capacity of the rivers) and identifying threshold salt concentrations to preserve the ecosystem integrity. Future research on the interaction of salinity with other stressors and the impact of salinization on trophic interactions and ecosystem properties is needed and the implications of this issue for human society need to be seriously considered. Copyright © 2012 Elsevier Ltd. All rights reserved.

Temperature measurement of supercooled droplet in icing phenomenon by means of dual-luminescent imaging

NASA Astrophysics Data System (ADS)

Tanaka, M.; Morita, K.; Mamori, H.; Fukushima, N.; Yamamoto, M.

2017-08-01

The collision of a supercooled water droplet with a surface result an object creates ice accretion on the surface. The icing problem in any cold environments leads to severe damages on aircrafts, and a lot of studies on prevention and prediction techniques for icing have been conducted so far. Therefore, it is very important to know the detail of freezing mechanism of supercooled water droplets to improve the anti-and de-icing devices and icing simulation codes. The icing mechanism of a single supercooled water droplet impacting on an object surface would give us great insights for the purpose. In the present study, we develop a dual-luminescent imaging technique to measure the time-resolved temperature of a supercooled water droplet impacting on the surface under different temperature conditions. We apply this technique to measure the exact temperature of a water droplet, and to discuss the detail of the freezing process.

Location-based information retrieval framework

NASA Astrophysics Data System (ADS)

Hariharan, Gurushyam; Mehta, Sandeep

2003-03-01

The recent advances in mobile communication technologies and their widespread use calls for a host of new value added services for the mobile user. In their current avatar, these deices are not more than mere communication equipments. Now consumer orientated, mobile, internet connected devices which are location aware (that are capable of determining and transmitting their current geographical location) are becoming available everywhere. The availability of internet access and location awareness in portable devices like cell phones, Personal Digital Assistants, etc. opens up a host of new opportunities for services which can en cash on the location of the user. Besides providing navigational information to the user, additional push down information can be sent to the user based on his profile and his preferences. The domain is wide and the number of applications is enormous. This paper presents a design and implementation of a basic location aware service.

Effect of Ice Formations on Section Drag of Swept NACA 63A-009 Airfoil with Partical-span Leading-edge Slat for Various Modes of Thermal Ice Protection

NASA Technical Reports Server (NTRS)

Von Glahn, Uwe H; Gray, Vernon H

1954-01-01

Studies were made to determine the effect of ice formations on the section drag of a 6.9-foot-chord 36 degree swept NACA 63A-009 airfoil with partial-span leading-edge slat. In general, the icing of a thin swept airfoil will result in greater aerodynamic penalties than for a thick unswept airfoil. Glaze-ice formations at the leading edge of the airfoil caused large increases in section drag even at liquid-water content of 0.39 gram per cubic meter. The use of an ice-free parting strip in the stagnation region caused a negligible change in drag compared with a completely unheated airfoil. Cyclic de-icing when properly applied caused the drag to decrease almost to the bare-airfoil drag value.

Benefits assessment of active control technology and related cockpit technology for rotorcraft

NASA Technical Reports Server (NTRS)

Hampton, B. J.

1982-01-01

Two main-rotor active control concepts, one incorporating multicyclic actuators located just below the swashplate, and the other providing for the actuators and power supplies to be located in the rotating frame are considered. Each design concept is integrated with cockpit controllers and displays appropriate to the actuation concept in each case. The benefits of applying the defined ACT/RCT concepts to rotorcraft are quantified by comparison to the baseline model 412 helicopter. These benefits include, in the case of one active control concept; (1) up to 91% reduction in 4/rev hub shears; (2) a flight safety failure rate of 1.96 x 10 to the 8th power failures per flight-hour; (3) rotating controls/rotor hub drag reduction of 40%; (4) a 9% reduction in control system weight; and (5) vibratory deicing. The related cockpit concept reduces pilot workload for critical mission segments as much as 178% visual and 25% manual.

Preliminary assessment of chloride concentrations, loads, and yields in selected watersheds along the Interstate 95 corridor, southeastern Connecticut, 2008-09

USGS Publications Warehouse

Brown, Craig J.; Mullaney, John R.; Morrison, Jonathan; Mondazzi, Remo

2011-01-01

Water-quality conditions were assessed to evaluate potential effects of road-deicer applications on stream-water quality in four watersheds along Interstate 95 (I-95) in southeastern Connecticut from November 1, 2008, through September 30, 2009. This preliminary study is part of a four-year cooperative study by the U.S. Geological Survey (USGS), the Federal Highway Administration (FHWA), and the Connecticut Department of Transportation (ConnDOT). Streamflow and water quality were studied at four watersheds?Four Mile River, Oil Mill Brook, Stony Brook, and Jordan Brook. Water-quality samples were collected and specific conductance was measured continuously at paired water-quality monitoring sites upstream and downstream from I-95. Specific conductance values were related to chloride (Cl) concentrations to assist in determining the effects of road-deicing operations on the levels of Cl in the streams. Streamflow and water-quality data were compared with weather data and with the timing, amount, and composition of deicers applied to state highways. Grab samples were collected during winter stormwater-runoff events, such as winter storms or periods of rain or warm temperatures in which melting takes place, and periodically during the spring and summer. Cl concentrations at the eight water-quality monitoring sites were well below the U.S. Environmental Protection Agency (USEPA) recommended chronic and acute Cl toxicity criteria of 230 and 860 milligrams per liter (mg/L), respectively. Specific conductance and estimated Cl concentrations in streams, particularly at sites downstream from I-95, peaked during discharge events in the winter and early spring as a result of deicers applied to roads and washed off by stormwater or meltwater. During winter storms, deicing activities, or subsequent periods of melting, specific conductance and estimated Cl concentrations peaked as high as 703 microsiemens per centimeter (?S/cm) and 160 mg/L at the downstream sites. During most of the spring and summer, specific conductance and estimated Cl concentrations decreased during discharge events because the low-ionic strength of stormwater had a diluting effect on stream-water quality. However, peaks in specific conductance and estimated Cl concentrations at Jordan Brook and Stony Brook corresponded to peaks in streamflow well after winter snow or ice events; these delayed peaks in Cl concentration likely resulted from deicing salts that remained in melting snow piles and (or) that were flushed from soils and shallow groundwater, then discharged downstream. Cl loads in streams generally were highest in the winter and early spring. The estimated load for the period of record at the four monitoring sites downstream from I-95 ranged from 0.33 ton per day (ton/d) at the Stony Brook watershed to 0.59 ton/d at the Jordan Brook watershed. The Cl yields ranged from 0.07 ton per day per square mile (ton/d/)mi2) at Oil Mill Brook, one of the least developed watersheds, to 0.21 (ton/d)/mi2) at Jordan Brook, the watershed with the highest percentage of urban development and impervious surfaces. The median estimates of Cl load from atmospheric deposition ranged from 11 to 19 tons, and contributed 4.3 to 7.1 percent of the Cl load in streamflow from the watershed areas. A comparison of the Cl load input and output estimates indicates that less Cl is leaving the watersheds than is entering through atmospheric deposition and application of deicers. The lag time between introduction of Cl to the watershed and transport to the stream, and uncertainty in the load estimates may be the reasons for this discrepancy. In addition, estimates of direct infiltration of Cl to groundwater from atmospheric deposition, deicer applications, and septic-tank drainfields to groundwater were outside the scope of the November 2008 to September 2009 assessment. However, increased concentrations of ions were observed between upstream and downstream sites and could result from deicer appli

Convective Heat Transfer from Castings of Ice Roughened Surfaces in Horizontal Flight

NASA Technical Reports Server (NTRS)

Dukhan, Nihad; Vanfossen, G. James, Jr.; Masiulaniec, K. Cyril; Dewitt, Kenneth J.

1995-01-01

A technique was developed to cast frozen ice shapes that had been grown on a metal surface. This technique was applied to a series of ice shapes that were grown in the NASA Lewis Icing Research Tunnel on flat plates. Eight different types of ice growths, characterizing different types of roughness, were obtained from these plates, from which aluminum castings were made. Test strips taken from these castings were outfitted with heat flux gages, such that when placed in a dry wind tunnel, they could be used to experimentally map out the convective heat transfer coefficient in the direction of flow from the roughened surfaces. The effects on the heat transfer coefficient for parallel flow, which simulates horizontal flight, were studied. The results of this investigation can be used to help size heaters for wings, helicopter rotor blades, jet engine intakes, etc., or de-icing for anti-icing applications where the flow is parallel to the iced surface.

Analysis of potassium formate in airport storm water runoff by headspace solid-phase microextraction and gas chromatography-mass spectrometry.

PubMed

Fries, Elke; Klasmeier, Jörg

2009-01-30

Potassium formate was extracted from airport storm water runoff by headspace solid-phase microextraction (HS-SPME) and analyzed by GC-MS. Formate was transformed to formic acid by adding phosphoric acid. Subsequently, formic acid was derivatized to methyl formate by adding methanol. Using sodium [(2)H]formate (formate-d) as an internal standard, the relative standard deviation of the peak area ratio of formate (m/z 60) and formate-d (m/z 61) was 0.6% at a concentration of 208.5 mg L(-1). Calibration was linear in the range of 0.5-208.5 mg L(-1). The detection limit calculated considering the blank value was 0.176 mg L(-1). The mean concentration of potassium formate in airport storm water runoff collected after surface de-icing operations was 86.9 mg L(-1) (n=11) with concentrations ranging from 15.1 mg L(-1) to 228.6 mg L(-1).

Effects of Substitutions on the Biodegradation Potential of Benzotriazole Derivatives

NASA Astrophysics Data System (ADS)

Abu-Dalo, M. A.; O'Brien, I.; Hernandez, M. T.

2018-02-01

Fourteen benzotriazole derivatives were subjected to microcosm tests to study the influence of substitutions on their biodegradation potential. Methylated, nitrated, carboxylated, and propionated bezotriazoles, a heterocyclic triazole, as well as methylated benzimidazoles, were introduced to activated sludge and soil enrichment cultures as the only carbon source. Some of the enrichment cultures were derived from airport soils that had been previously contaminated with aircraft deicing fluids and subsequently enriched with the commercially significant corrosion inhibitor methylbenzotriazole. The 5-methylbenzotriazole and only the carboxylated derivatives were degraded by soil or activated sludge biomass regardless of acclimation conditions. Radiotracer studies of [U-14C] 5-methylbenzotriazole, and [U-14C] 5-carboxybenzotriazole confirmed that relatively high concentrations (25mg L-1) of these derivatives can be completely mineralized in relatively short time frames by microbial consortia regardless of prior exposure. Observations suggested that the growth yield on these compounds is likely low. Biodegradation patterns suggested that carboxylated benzotriazole derivatives are more readily biodegradable than their more popular methylated counterparts.

Embedded fiber optic sensors for bridge deck chloride penetration measurements

NASA Astrophysics Data System (ADS)

Fuhr, Peter L.; Huston, Dryver R.; MacCraith, Brian D.

1998-04-01

The use of chloride-based deicing agents to help clear U.S. highways of roadway hazards leads to associated chemical related problems. Fouling of local rivers and streams due to runoff of the waterborne chlorides is significant and has contributed to local ordinances that are attempting to force state agencies to reduce, if not eliminate, the use of these chlorides (typically at the cost of increased driving hazards). With respect to the corrosion aspects of chloride application, cracks that occur in the roadway/bridge pavement allow water to seep into the pavement carrying the chloride to the rebar with the resultant increase in corrosion. The costs of this corrosion are considerable and have led to the wide- spread use of chloride/water impermeable membranes on roadways and especially within bridges. Fiber optics sensors have repeatedly been shown to provide measurement capabilities of parameters within such reinforced concrete structures. Development of fiber optic chloride sensors capable of being embedded within a roadway or bridge deck is reported.

Fiber optic chloride sensing: if corrosion's the problem, chloride sensing is the key

NASA Astrophysics Data System (ADS)

Fuhr, Peter L.; MacCraith, Brian D.; Huston, Dryver R.; Guerrina, Mario; Nelson, Matthew

1997-09-01

The use of chloride-based deicing agents to help clear US highways of roadway hazards leads to associated chemical related problems. Fouling of local rivers and streams due to runoff of the water borne chlorides is significant and has contributed to local ordances are attempting to force state agencies to reduce, if not eliminate, the use of these chlorides. With respect to the corrosion aspects of chloride application, cracks that occur in the roadway/bridge pavement allow water to seep into the pavement carrying the chloride to the rebar with the resultant increase in corrosion. The costs of this corrosion are considerable and have led to the widespread use of chloride/water impermeable membranes on roadways and especially within bridges. Fiber optic sensor have repeatedly been shown to provide measurement capabilities of parameters within such reinforced concrete structures. Development of a fiber optic chloride sensors capable of being embedded within a roadway or bridge deck is reported.

Single pilot IFR operating problems determined from accidental data analysis

NASA Technical Reports Server (NTRS)

Forsyth, D. L.; Shaughnessy, J. D.

1978-01-01

The accident reports examined were restricted to instrument rated pilots flying in IFR weather. A brief examination was made of accidents which occurred during all phases of flight and which were due to all causes. A detailed examination was made of those accidents which involved a single pilot which occurred during the landing phases of flight, and were due to pilot error. Problem areas found include: (1) landing phase operations especially final approach, (2) pilot weather briefings, (3) night approaches in low IFR weather, (4) below minimum approaches, (5) aircraft icing, (6) imprecise navigation, (7) descending below minimum IFR altitudes, (8) fuel mismanagement, (9) pilot overconfidence, and (10) high pilot workload especially in twins. Some suggested areas of research included: (1) low cost deicing systems, (2) standardized navigation displays, (3) low cost low-altitude warning systems, (4) improved fuel management systems, (5) improved ATC communications, (6) more effective pilot training and experience acquisition methods, and (7) better weather data dissemination techniques.

Effects of morphology parameters on anti-icing performance in superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Nguyen, Thanh-Binh; Park, Seungchul; Lim, Hyuneui

2018-03-01

In this paper, we report the contributions of actual ice-substrate contact area and nanopillar height to passive anti-icing performance in terms of adhesion force and freezing time. Well-textured nanopillars with various parameters were fabricated via colloidal lithography and a dry etching process. The nanostructured quartz surface was coated with low-energy material to confer water-repellent properties. These superhydrophobic surfaces were investigated to determine the parameters essential for reducing adhesion strength and delaying freezing time. A well-textured surface with nanopillars of very small top diameter, regardless of height, could reduce adhesion force and delay freezing time in a subsequent de-icing process. Small top diameters of nanopillars also ensured the metastable Cassie-Baxter state based on energy barrier calculations. The results demonstrated the important role of areal fraction in anti-icing efficiency, and the negligible contribution of texture height. This insight into icing phenomena should lead to design of improved ice-phobic surfaces in the future.

Experimental Investigation of Concrete Runway Snow Melting Utilizing Heat Pipe Technology

PubMed Central

Su, Xin; Ye, Qing; Fu, Jianfeng

2018-01-01

A full scale snow melting system with heat pipe technology is built in this work, which avoids the negative effects on concrete structure and environment caused by traditional deicing chemicals. The snow melting, ice-freezing performance and temperature distribution characteristics of heat pipe concrete runway were discussed by the outdoor experiments. The results show that the temperature of the concrete pavement is greatly improved with the heat pipe system. The environment temperature and embedded depth of heat pipe play a dominant role among the decision variables of the snow melting system. Heat pipe snow melting pavement melts the snow completely and avoids freezing at any time when the environment temperature is below freezing point, which is secure enough for planes take-off and landing. Besides, the exportation and recovery of geothermal energy indicate that this system can run for a long time. This paper will be useful for the design and application of the heat pipe used in the runway snow melting. PMID:29551957

Experimental Investigation of Concrete Runway Snow Melting Utilizing Heat Pipe Technology.

PubMed

Chen, Fengchen; Su, Xin; Ye, Qing; Fu, Jianfeng

2018-01-01

A full scale snow melting system with heat pipe technology is built in this work, which avoids the negative effects on concrete structure and environment caused by traditional deicing chemicals. The snow melting, ice-freezing performance and temperature distribution characteristics of heat pipe concrete runway were discussed by the outdoor experiments. The results show that the temperature of the concrete pavement is greatly improved with the heat pipe system. The environment temperature and embedded depth of heat pipe play a dominant role among the decision variables of the snow melting system. Heat pipe snow melting pavement melts the snow completely and avoids freezing at any time when the environment temperature is below freezing point, which is secure enough for planes take-off and landing. Besides, the exportation and recovery of geothermal energy indicate that this system can run for a long time. This paper will be useful for the design and application of the heat pipe used in the runway snow melting.

Concrete filled steel pipe inspection using electro magnetic acoustic transducer (EMAT)

NASA Astrophysics Data System (ADS)

Na, Won-Bae; Kundu, Tribikram; Ryu, Yeon-Sun; Kim, Jeong-Tae

2005-05-01

Concrete-filled steel pipes are usually exposed in hostile environments such as seawater and deicing materials. The outside corrosion of the steel pipe can reduce the wall thickness and the corrosion-induced delamination of internal concrete can increase internal volume or pressure. In addition, the void that can possibly exist in the pipe reduces the bending resistance. To avoid structural failure due to this type of deterioration, appropriate inspection and repair techniques are to be developed. Guided wave techniques have strong potentials for this kind of inspection because of long-distance inspection capability. Among different transducer-coupling mechanism, electro-magnetic acoustic transducers (EMATs) give relatively consistent results in comparison to piezoelectric transducers since they do not need any couplant. In this study EMATs are used for transmitting and receiving cylindrical guided waves through concrete-filled steel pipes. Through time history curves and wavelet transform, it is shown that EMAT-generated cylindrical guided wave techniques have good potential for the interface inspection of concrete-filled steel pipes.

Reactive powder based concretes: Mechanical properties, durability and hybrid use with OPC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cwirzen, A.; Penttala, V.; Vornanen, C.

2008-10-15

The basic mechanical properties, frost durability and the bond strength with normal strength concretes of the ultra high strength (UHS) mortars and concretes were studied. The produced mixes had plastic or fluid-like consistency. The 28-day compressive strength varied between 170 and 202 MPa for the heat-treated specimens and between 130 and 150 MPa for the non-heat-treated specimens. The shrinkage values were two times higher for the UHS mortars in comparison with the UHS concretes. After the initial shrinkage, swelling was noticed in the UHS mortars. The lowest creep values were measured for the non-heat-treated UHS concretes. The frost-deicing salts durabilitymore » of the UHS mortars and concretes appeared to be very good even despite the increased water uptake of the UHS concretes. The study of the hybrid concrete beams indicated the formation of low strength transition zone between the UHS mortar and normal strength concrete.« less

Hydrophobic durability characteristics of butterfly wing surface after freezing cycles towards the design of nature inspired anti-icing surfaces

PubMed Central

Choy, Kwang-Leong

2018-01-01

The hydrophobicity and anti-icing performance of the surfaces of some artificial hydrophobic coatings degraded after several icing and de-icing cycles. In this paper, the frost formation on the surfaces of butterfly wings from ten different species was observed, and the contact angles were measured after 0 to 6 frosting/defrosting cycles. The results show that no obvious changes in contact angle for the butterfly wing specimens were not obvious during the frosting/defrosting process. Further, the conclusion was inferred that the topography of the butterfly wing surface forms a special space structure which has a larger space inside that can accommodate more frozen droplets; this behavior prevents destruction of the structure. The findings of this study may provide a basis and new concepts for the design of novel industrially important surfaces to inhibit frost/ice growth, such as durable anti-icing coatings, which may decrease or prevent the socio-economic loss. PMID:29385390

Hydrophobic durability characteristics of butterfly wing surface after freezing cycles towards the design of nature inspired anti-icing surfaces.

PubMed

Chen, Tingkun; Cong, Qian; Qi, Yingchun; Jin, Jingfu; Choy, Kwang-Leong

2018-01-01

The hydrophobicity and anti-icing performance of the surfaces of some artificial hydrophobic coatings degraded after several icing and de-icing cycles. In this paper, the frost formation on the surfaces of butterfly wings from ten different species was observed, and the contact angles were measured after 0 to 6 frosting/defrosting cycles. The results show that no obvious changes in contact angle for the butterfly wing specimens were not obvious during the frosting/defrosting process. Further, the conclusion was inferred that the topography of the butterfly wing surface forms a special space structure which has a larger space inside that can accommodate more frozen droplets; this behavior prevents destruction of the structure. The findings of this study may provide a basis and new concepts for the design of novel industrially important surfaces to inhibit frost/ice growth, such as durable anti-icing coatings, which may decrease or prevent the socio-economic loss.

A Novel Concrete-Based Sensor for Detection of Ice and Water on Roads and Bridges

PubMed Central

Aljuboori, Mohammed

2017-01-01

Hundreds of people are killed or injured annually in the United States in accidents related to ice formation on roadways and bridge decks. In this paper, a novel embedded sensor system is proposed for the detection of black ice as well as wet, dry, and frozen pavement conditions on roads, runways, and bridges. The proposed sensor works by detecting changes in electrical resistance between two sets of stainless steel poles embedded in the concrete sensor to assess surface and near-surface conditions. A preliminary decision algorithm is developed that utilizes sensor outputs indicating resistance changes and surface temperature. The sensor consists of a 102-mm-diameter, 38-mm-high, concrete cylinder. Laboratory results indicate that the proposed sensor can effectively detect surface ice and wet conditions even in the presence of deicing chlorides and rubber residue. This sensor can further distinguish black ice from ice that may exist within concrete pores. PMID:29240710

The Effects of Salt on Rheological Properties of Asphalt after Long-Term Aging

PubMed Central

Yu, Xin; Luo, Yilin; Yin, Long

2013-01-01

Limited studies in recent years have shown that asphalt pavement subject to seawater in coastal regions or deicing salt in cold regions may be seriously damaged after being soaked in saline water for a long time. However, there is limited research into the influence of salt on rheological properties of asphalt after long-term aging. In this study, rheological properties of unmodified and polymer-modified asphalt after long-term aging were tested after being soaked in different concentrations of salt (0.3%~5%) for different durations (1 day~30 days). Orthogonal array based on the Taguchi method was used for experimental design. The frequency sweep tests were performed on the specimens of aged asphalt after being soaked for complex modulus and phase angle master curves and ultimate fatigue temperature. BBR tests were performed for stiffness. The test results indicate that saline water appears to reduce low temperature properties and fatigue resistance properties and improved high temperature properties of aged asphalt, and it also affects the sensitivity of complex modulus and phase angles at low frequencies. PMID:24459450

Designing durable icephobic surfaces

PubMed Central

Golovin, Kevin; Kobaku, Sai P. R.; Lee, Duck Hyun; DiLoreto, Edward T.; Mabry, Joseph M.; Tuteja, Anish

2016-01-01

Ice accretion has a negative impact on critical infrastructure, as well as a range of commercial and residential activities. Icephobic surfaces are defined by an ice adhesion strength τice < 100 kPa. However, the passive removal of ice requires much lower values of τice, such as on airplane wings or power lines (τice < 20 kPa). Such low τice values are scarcely reported, and robust coatings that maintain these low values have not been reported previously. We show that, irrespective of material chemistry, by tailoring the cross-link density of different elastomeric coatings and by enabling interfacial slippage, it is possible to systematically design coatings with extremely low ice adhesion (τice < 0.2 kPa). These newfound mechanisms allow for the rational design of icephobic coatings with virtually any desired ice adhesion strength. By using these mechanisms, we fabricate extremely durable coatings that maintain τice < 10 kPa after severe mechanical abrasion, acid/base exposure, 100 icing/deicing cycles, thermal cycling, accelerated corrosion, and exposure to Michigan wintery conditions over several months. PMID:26998520

Effect of Molecular Flexibility upon Ice Adhesion Shear Strength

NASA Technical Reports Server (NTRS)

Smith, Joseph G.; Wohl, Christopher J.; Kreeger, Richard E.; Palacios, Jose; Knuth, Taylor; Hadley, Kevin

2016-01-01

Ice formation on aircraft surfaces effects aircraft performance by increasing weight and drag leading to loss of lift. Current active alleviation strategies involve pneumatic boots, heated surfaces, and usage of glycol based de-icing fluids. Mitigation or reduction of in-flight icing by means of a passive approach may enable retention of aircraft capabilities, i.e., no reduction in lift, while reducing the aircraft weight and mechanical complexity. Under a NASA Aeronautics Research Institute Seedling activity, the effect of end group functionality and chain length upon ice adhesion shear strength (IASS) was evaluated with the results indicating that chemical functionality and chain length (i.e. molecular flexibility) affected IASS. Based on experimental and modeling results, diamine monomers incorporating molecular flexibility as either a side chain or in between diamine functionalities were prepared, incorporated into epoxy resins that were subsequently used to fabricate coatings on aluminum substrates, and tested in a simulated icing environment. The IASS was found to be lower when molecular flexibility was incorporated in the polymer chain as opposed to a side chain.

Toxicity of benzotriazole and benzotriazole derivatives to three aquatic species.

PubMed

Pillard, D A; Cornell, J S; Dufresne, D L; Hernandez, M T

2001-02-01

Benzotriazole and its derivatives comprise an important class of corrosion inhibitors, typically used as trace additives in industrial chemical mixtures such as coolants, deicers, surface coatings, cutting fluids, and hydraulic fluids. Recent studies have shown that benzotriazole derivatives are a major component of aircraft deicing fluids (ADFs) responsible for toxicity to bacteria (Microtox). Our current research compared the toxicity of benzotriazole (BT), two methylbenzotriazole (MeBT) isomers, and butylbenzotriazole (BBT). Acute toxicity assays were used to model the response of three common test organisms: Microtox bacteria (Vibrio fischeri), fathead minnow (Pimephales promelas) and water flea (Ceriodaphnia dubia). The response of all the three organisms varied over two orders of magnitude among all compounds. Vibrio fischeri was more sensitive than either C. dubia or P. promelas to all the test materials, while C. dubia was less sensitive than P. promelas. The response of test organisms to unmethylated benzotriazole and 4-methylbenzotriazole was similar, whereas 5-methylbenzotriazole was more toxic than either of these two compounds. BBT was the most toxic benzotriazole derivative tested, inducing acute toxicity at a concentration of < or = 3.3 mg/l to all organisms.

60NiTi Intermetallic Material Evaluation for Lightweight and Corrosion Resistant Spherical Sliding Bearings for Aerospace Applications

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Jefferson, Michael

2015-01-01

NASA Glenn Research Center and the Kamatics subsidiary of the Kaman Corporation conducted the experimental evaluation of spherical sliding bearings made with 60NiTi inner races. The goal of the project was to assess the feasibility of manufacturing lightweight, corrosion resistant bearings utilizing 60NiTi for aerospace and industrial applications. NASA produced the bearings in collaboration with Abbott Ball Corporation and Kamatics fabricated bearing assemblies utilizing their standard reinforced polymer liner material. The assembled bearings were tested in oscillatory motion at a load of 4.54kN (10,000 lb), according to the requirements of the plain bearing specification SAE AS81820. Several test bearings were exposed to hydraulic fluid or aircraft deicing fluid prior to and during testing. The results show that the 60NiTi bearings exhibit tribological performance comparable to conventional stainless steel (440C) bearings. Further, exposure of 60NiTi bearings to the contaminant fluids had no apparent performance effect. It is concluded that 60NiTi is a feasible bearing material for aerospace and industrial spherical bearing applications.

Temperature distribution of a water droplet moving on a heated super-hydrophobic surface under the icing condition

NASA Astrophysics Data System (ADS)

Yamazaki, Masafumi; Sumino, Yutaka; Morita, Katsuaki

2017-11-01

In the aviation industry, ice accretion on the airfoil has been a hazardous issue since it greatly declines the aerodynamic performance. Electric heaters and bleed air, which utilizes a part of gas emissions from engines, are used to prevent the icing. Nowadays, a new de-icing system combining electric heaters and super hydrophobic coatings have been developed to reduce the energy consumption. In the system, the heating temperature and the coating area need to be adjusted. Otherwise, the heater excessively consumes energy when it is set too high and when the coating area is not properly located, water droplets which are once dissolved possibly adhere again to the rear part of the airfoil as runback ice In order to deal with these problems, the physical phenomena of water droplets on the hydrophobic surface demand to be figured out. However, not many investigations focused on the behavior of droplets under the icing condition have been conducted. In this research, the temperature profiling of the rolling droplet on a heated super-hydrophobic surface is experimentally observed by the dual luminescent imaging.

Icing-Protection Requirements for Reciprocating-Engine Induction System

NASA Technical Reports Server (NTRS)

Coles, Willard D; Rollin, Vern G; Mulholland, Donald R

1950-01-01

Despite the development of relatively ice-free fuel-metering systems, the widespread use of alternate and heated-air intakes, and the use of alcohol for emergency de-icing, icing of aircraft-engine induction systems is a serious problem. Investigations have been made to study and to combat all phases of this icing problem. From these investigations, criterions for safe operation and for design of new induction systems have been established. The results were obtained from laboratory investigations of carburetor-supercharger combinations, wind-tunnel investigations of air scoops, multicylinder-engine studies, and flight investigations. Characteristics of three forms of ice, impact, throttling, and fuel evaporation were studied. The effects of several factors on the icing characteristics were also studied and included: (1) atmospheric conditions, (2) engine and air-scoop configurations, including light-airplane system, (3) type fuel used, and (4) operating variables, such as power condition, use of a manifold pressure regulator, mixture setting, carburetor heat, and water-alcohol injection. In addition, ice-detection methods were investigated and methods of preventing and removing induction-system ice were studied. Recommendations are given for design and operation with regard to induction-system design.

The effects of salt on rheological properties of asphalt after long-term aging.

PubMed

Yu, Xin; Wang, Ying; Luo, Yilin; Yin, Long

2013-01-01

Limited studies in recent years have shown that asphalt pavement subject to seawater in coastal regions or deicing salt in cold regions may be seriously damaged after being soaked in saline water for a long time. However, there is limited research into the influence of salt on rheological properties of asphalt after long-term aging. In this study, rheological properties of unmodified and polymer-modified asphalt after long-term aging were tested after being soaked in different concentrations of salt (0.3%~5%) for different durations (1 day~30 days). Orthogonal array based on the Taguchi method was used for experimental design. The frequency sweep tests were performed on the specimens of aged asphalt after being soaked for complex modulus and phase angle master curves and ultimate fatigue temperature. BBR tests were performed for stiffness. The test results indicate that saline water appears to reduce low temperature properties and fatigue resistance properties and improved high temperature properties of aged asphalt, and it also affects the sensitivity of complex modulus and phase angles at low frequencies.

Aggregate-cement paste transition zone properties affecting the salt-frost damage of high-performance concretes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cwirzen, Andrzej; Penttala, Vesa

2005-04-01

The influence of the cement paste-aggregate interfacial transition zone (ITZ) on the frost durability of high-performance silica fume concrete (HPSFC) has been studied. Investigation was carried out on eight non-air-entrained concretes having water-to-binder (W/B) ratios of 0.3, 0.35 and 0.42 and different additions of condensed silica fume. Studies on the microstructure and composition of the cement paste have been made by means of environmental scanning electron microscope (ESEM)-BSE, ESEM-EDX and mercury intrusion porosimetry (MIP) analysis. The results showed that the transition zone initiates and accelerates damaging mechanisms by enhancing movement of the pore solution within the concrete during freezing andmore » thawing cycles. Cracks filled with ettringite were primarily formed in the ITZ. The test concretes having good frost-deicing salt durability featured a narrow transition zone and a decreased Ca/Si atomic ratio in the transition zone compared to the bulk cement paste. Moderate additions of silica fume seemed to densify the microstructure of the ITZ.« less

An Experimental Investigation on Bio-inspired Icephobic Coatings for Aircraft Icing Mitigation

NASA Astrophysics Data System (ADS)

Hu, Hui; Li, Haixing; Waldman, Rye

2016-11-01

By leveraging the Icing Research Tunnel available at Iowa State University (ISU-IRT), a series of experimental investigations were conducted to elucidate the underlying physics pertinent to aircraft icing phenomena. A suite of advanced flow diagnostic techniques, which include high-speed photographic imaging, digital image projection (DIP), and infrared (IR) imaging thermometry, were developed and applied to quantify the transient behavior of water droplet impingement, wind-driven surface water runback, unsteady heat transfer and dynamic ice accreting process over the surfaces of airfoil/wing models. The icephobic performance of various bio-inspired superhydrophobic coatings were evaluated quantitatively at different icing conditions. The findings derived from the icing physics studies can be used to improve current icing accretion models for more accurate prediction of ice formation and accretion on aircraft wings and to develop effective anti-/deicing strategies for safer and more efficient operation of aircraft in cold weather. The research work is partially supported by NASA with Grant Number NNX12AC21A and National Science Foundation under Award Numbers of CBET-1064196 and CBET-1435590.

Chloride loading in the South Fork of the Shenandoah River, Virginia, U.S.A.

NASA Astrophysics Data System (ADS)

Sherwood, W. Cullen

1989-09-01

Loading trends and sources of CI- in the South Fork of the Shenandoah River, Virginia were analyzed for the period 1929 1982. CI- has increased from approximately 2 mg/L (2,776 tons/yr) to over 10 mg/L (14,256 tons/yr). Natural CI- is estimated to be 1.01 mg/L (1,388 tons/yr) with precipitation providing 0.99 mg/L and rocks 0.02 mg/L. From 1929 to 1949 CI- concentrations were relatively constant and independent of discharge, conforming to the Type II curve of Davis and Zobrist (1978), indicative of natural or relatively uncontaminated streams. Since 1952 CI- concentrations increased exponentially as river discharge decreases conforming to the Type I curve of Davis and Zobrist for polluted streams. Since 1965 anthropogenic CI- loading at 12,868 tons/yr has remained relatively constant. Four major sources contribute 92.2 percent (11,871 tons/yr) of the anthropogenic CI-: (1) deicing salts—4,149 tons/yr, (2) domestic sewage—3,015 tons/yr, (3) livestock and poultry wastes—2,458 tons/yr, and (4) commercial fertilizers—2,249 tons/yr.

Highlights from the SoilCAM project: Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring

NASA Astrophysics Data System (ADS)

French, H. K.; van der Zee, S. E. A. T. M.; Wehrer, M.; Godio, A.; Pedersen, L. B.; Toscano, G.

2012-04-01

The SoilCAM project (Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring 2008-2012, EU-FP7-212663) is aimed at improving current methods for monitoring contaminant distribution and biodegradation in the subsurface. At two test sites, Oslo airport Gardermoen in Norway and the Trecate site in Italy, a number of geophysical techniques, lysimeter and other soil and water sampling techniques as well as numerical flow and transport modelling have been combined at different scales in order to characterise flow transport processes in the unsaturated and saturated zones. Laboratory experiments have provided data on physical and bio-geo-chemical parameters for use in models and to select remediation methods. The geophysical techniques were used to map geological heterogeneities and also conduct time-lapse measurements of processes in the unsaturated zone. Both cross borehole and surface electrodes were used for electrical resistivity and induced polarisation surveys. The geophysical surveys showed clear indications of areas highly affected by de-icing chemicals along the runway at Oslo airport. The time lapse measurements along the runway at the airport show infiltration patterns during snowmelt and are used to validate 2D unsaturated flow and transport simulations using SUTRA. The Orchestra model is used to describe the complex interaction between bio-geo-chemical processes in a 1D profile along the runway. The presence of installations such as a membrane along the runway highly affects the flow pattern and challenges the capacity of the numerical code. Smaller scale field site measurements have revealed the increase of iron and manganese during degradation of de-icing chemicals. The use of Nitrate to increase red-ox potential was tested, but results have not been analysed yet. So far it cannot be concluded that degradation process can be quantified indirectly by geophysical monitoring. At the Trecate site a combination of georadar, electrical resistivity and radio magneto telluric provided a broad outline of the geology down to 50 m, there is a good consistency in the data in the overlapping part, and more deep samples would be required to validate the geological interpretation of the data. Anomalies in the Induced polarisation and electrical resistivity data from the cross borehole measurements indicate where the remaining crude oil can be found. Water samples from multilevel samplers reveal crude oil present in emulsion in the zone of groundwater fluctuations, highlighting the importance of colloidal transport. Geochemistry of the groundwater clearly indicates degradation of hydrocarbons under iron- and sulphate reducing conditions. Modflow has been used to simulate the regional groundwater flow and transport in the area. An overview of the work that has been conducted and main highlights of the results so far will be presented.

Anaerobic degradation of aircraft deicing fluid (ADF) in upflow anaerobic sludge blanket (UASB) reactors and the fate of ADF additives

NASA Astrophysics Data System (ADS)

Pham, Thi Tham

2002-11-01

A central composite design was employed to methodically investigate anaerobic treatment of aircraft deicing fluid (ADF) in bench-scale Upflow Anaerobic Sludge Blanket (UASB) reactors. A total of 23 runs at 17 different operating conditions were conducted in continuous mode. The development of four empirical models describing process responses (i.e., chemical oxygen demand (COD) removal efficiency, biomass specific acetoclastic activity, methane production rate, and methane production potential) as functions of ADF concentration, hydraulic retention time (HRT), and biomass concentration is presented. Model verification indicated that predicted responses (COD removal efficiencies, biomass specific acetoclastic activity, and methane production rates and potential) were in good agreement with experimental results. Biomass specific acetoclastic activity was improved by almost two-fold during ADF treatment in UASB reactors. For the design window, COD removal efficiencies were higher than 90%. Predicted methane production potentials were close to theoretical values, and methane production rates increased as the organic loading rate (OLR) was increased. ADF toxicity effects were evident for 1.6% ADF at medium specific organic loadings (SOLR above 0.5 g COD/g VSS/d). In contrast, good reactor stability and excellent removal efficiencies were achieved at 1.2% ADF for reactor loadings approaching that of highly loaded systems (0.73 g COD/g VSS/d). Acclimation to ADF resulted in an initial reduction in the biomass settling velocity. The fate of ADF additives was also investigated. There was minimal sorption of benzotriazole (BT), 5-methyl-1 H-benzotriazole (MeBT), and 5,6-dimethyl-1 H-benzotriazole (DiMeBT) to anaerobic granules. A higher sorption capacity was measured for NP. Active transport may be one of the mechanisms for NP sorption. Ethylene glycol degradation experiments indicated that BT, MeBT, DiMeBT, and the nonionic surfactant Tergitol NP-4 had no significant effects on acidogenesis and methanogenesis at the concentration levels studied. A significant inhibition of acetoclastic activity was observed for NP at 100 mg/L, with acetic acid consumption rate at 38% of that for controls. No evidence for anaerobic degradation of benzotriazole and its derivatives was observed; however, both batch and continuous experiments suggested that anaerobic degradation of NP occurred. Kinetic analysis of operational data obtained for the anaerobic treatment of ADF in UASB reactors indicated that the substrate utilization rate was independent of the reactor biomass concentration. The maximum rate of substrate utilization and the half-velocity constants for ADF treatment were 28.4 g COD/L/d and 648 mg COD/L, respectively. For 1.2% ADF, the biomass yield and endogenous decay coefficients were 0.027 g VSS/g COD and 0.012 d-1 , respectively.

The effects of de-icing in Helsinki urban streams, southern Finland.

PubMed

Ruth, O

2003-01-01

The environmental effects of road salt have been studied in Finland mainly in order to monitor and reduce groundwater contamination. In urban areas the road salt used for road maintenance in winter ends up in the storm water drains and receiving water bodies. We report here on water samples taken in 1998-1999 from three urban streams with catchments varying in area 1.7 to 24.4 km2 in different parts of the City of Helsinki. Despite efforts to reduce the amount of road salt, high concentrations were found in the urban stream water. Sudden variations in water quality were very marked during the spring flood period, with sodium and chloride concentrations varying over nine-fold within one day. Some 35-50% of the salt used on the roads in Helsinki passes into natural streams and from there into the sea. The significant positive correlation between NaCl and dissolved zinc in stream water was observed. The results show that it is important to monitor water quality, especially at the beginning of the spring flood period, when road salt and other contaminant levels are markedly high in urban streams.

Assessment of suspended solids concentration in highway runoff and its treatment implication.

PubMed

Hallberg, M; Renman, G

2006-09-01

It is understood that the major pollution from storm water is related to the content of particulate matter. One treatment practice is based on the first flush, i.e. detention of the initial part of the runoff that is considered to contain the highest concentrations of pollutants. This study has evaluated the concentration of total suspended solids in 30 consecutive runoff events during the winter season for an area of 6.7 hectares. A six-lane highway (E4) that has an annual average daily traffic load of 120,000 dominates the area and road de-icing salt (NaCl) and studded tires were in regular use during the studied period. The effluent standard for wastewater of 60 mg TSS per litre applied in EU was used to assess the treatment requirement of storm water. In only two of the events the event mean concentration was below 60 mg 1(-1). In four runoff events a partial event mean concentration below 60 mg 1(-1) was found, in 26 %, 12 %, 11 %, and 2 % respectively of the runoff volume. This would suggest that a capture of the initial part of the runoff for subsequent treatment is less applicable in this type of urban watershed.

Long-Term Climatic and Anthropogenic Impacts on Streamwater Salinity in New York State: INCA Simulations Offer Cautious Optimism.

PubMed

Gutchess, Kristina; Jin, Li; Ledesma, José L J; Crossman, Jill; Kelleher, Christa; Lautz, Laura; Lu, Zunli

2018-02-06

The long-term application of road salts has led to a rise in surface water chloride (Cl - ) concentrations. While models have been used to assess the potential future impacts of continued deicing practices, prior approaches have not incorporated changes in climate that are projected to impact hydrogeology in the 21st century. We use an INtegrated CAtchment (INCA) model to simulate Cl - concentrations in the Tioughnioga River watershed. The model was run over a baseline period (1961-1990) and climate simulations from a range of GCMs run over three 30-year intervals (2010-2039; 2040-2069; 2070-2099). Model projections suggest that Cl - concentrations in the two river branches will continue to rise for several decades, before beginning to decline around 2040-2069, with all GCM scenarios indicating reductions in snowfall and associated salt applications over the 21st century. The delay in stream response is most likely attributed to climate change and continued contribution of Cl - from aquifers. By 2100, surface water Cl - concentrations will decrease to below 1960s values. Catchments dominated by urban lands will experience a decrease in average surface water Cl - , although moderate compared to more rural catchments.

Evaluation and economic value of winter weather forecasts

NASA Astrophysics Data System (ADS)

Snyder, Derrick W.

State and local highway agencies spend millions of dollars each year to deploy winter operation teams to plow snow and de-ice roadways. Accurate and timely weather forecast information is critical for effective decision making. Students from Purdue University partnered with the Indiana Department of Transportation to create an experimental winter weather forecast service for the 2012-2013 winter season in Indiana to assist in achieving these goals. One forecast product, an hourly timeline of winter weather hazards produced daily, was evaluated for quality and economic value. Verification of the forecasts was performed with data from the Rapid Refresh numerical weather model. Two objective verification criteria were developed to evaluate the performance of the timeline forecasts. Using both criteria, the timeline forecasts had issues with reliability and discrimination, systematically over-forecasting the amount of winter weather that was observed while also missing significant winter weather events. Despite these quality issues, the forecasts still showed significant, but varied, economic value compared to climatology. Economic value of the forecasts was estimated to be 29.5 million or 4.1 million, depending on the verification criteria used. Limitations of this valuation system are discussed and a framework is developed for more thorough studies in the future.

Corrosion Prediction with Parallel Finite Element Modeling for Coupled Hygro-Chemo Transport into Concrete under Chloride-Rich Environment

PubMed Central

Na, Okpin; Cai, Xiao-Chuan; Xi, Yunping

2017-01-01

The prediction of the chloride-induced corrosion is very important because of the durable life of concrete structure. To simulate more realistic durability performance of concrete structures, complex scientific methods and more accurate material models are needed. In order to predict the robust results of corrosion initiation time and to describe the thin layer from concrete surface to reinforcement, a large number of fine meshes are also used. The purpose of this study is to suggest more realistic physical model regarding coupled hygro-chemo transport and to implement the model with parallel finite element algorithm. Furthermore, microclimate model with environmental humidity and seasonal temperature is adopted. As a result, the prediction model of chloride diffusion under unsaturated condition was developed with parallel algorithms and was applied to the existing bridge to validate the model with multi-boundary condition. As the number of processors increased, the computational time decreased until the number of processors became optimized. Then, the computational time increased because the communication time between the processors increased. The framework of present model can be extended to simulate the multi-species de-icing salts ingress into non-saturated concrete structures in future work. PMID:28772714

Estimation of corrosion damage in steel reinforced mortar using waveguides

NASA Astrophysics Data System (ADS)

Reis, Henrique; Ervin, Benjamin L.; Kuchma, Daniel A.; Bernhard, Jennifer

2005-05-01

Corrosion of reinforced concrete is a chronic infrastructure problem, particularly in areas with deicing salt and marine exposure. To maintain structural integrity, a testing method is needed to identify areas of corroding reinforcement. For purposes of rehabilitation, the method must also be able to evaluate the degree, rate and location of damage. Towards the development of a wireless embedded sensor system to monitor and assess corrosion damage in reinforced concrete, reinforced mortar specimens were manufactured with seeded defects to simulate corrosion damage. Taking advantage of waveguide effects of the reinforcing bars, these specimens were then tested using an ultrasonic approach. Using the same ultrasonic approach, specimens without seeded defects were also monitored during accelerated corrosion tests. Both the ultrasonic sending and the receiving transducers were mounted on the steel rebar. Advantage was taken of the lower frequency (<250 kHz) fundamental flexural propagation mode because of its relatively large displacements at the interface between the reinforcing steel and the surrounding concrete. Waveform energy (indicative of attenuation) is presented and discussed in terms of corrosion damage. Current results indicate that the loss of bond strength between the reinforcing steel and the surrounding concrete can be detected and evaluated.

Corrosion detection in reinforced concrete roadways and bridges via embedded fiber optic sensors

NASA Astrophysics Data System (ADS)

Fuhr, Peter L.; Huston, Dryver R.

1998-04-01

The problems associated with the application of chloride-based deicing agents to roadways and specifically bridges include chemical pollution and accelerated corrosion of strength members (especially the rebar) within the structure. In many instances, local ordnances are attempting to force state agencies to reduce, if not eliminate, the use of these chlorides (typically at the cost of increased driving hazards). With respect to the corrosion aspects of chloride application, cracks that occur in the roadway/bridge pavement allow water to seep into the pavement carrying the chloride to the rebar with the resultant increase in corrosion. In tandem with these efforts has been the continuing use of embedded fiber optic sensors for identification of faults or cracks within a highway structure - i.e., structural health monitoring. In this paper, we present multiple-parameter sensing fiber optic sensors which may be embedded into roadway and bridge structures to provide an internal measurement and assessment of its health. Such issues are paramount in determining if remedial or preventative maintenance should be performed on such structures. Laboratory results, comparisons with conventional sensing methods as well as a review of real-world issues in highway sensing are presented.

Multi-Functional Carbon Fibre Composites using Carbon Nanotubes as an Alternative to Polymer Sizing

PubMed Central

Pozegic, T. R.; Anguita, J. V.; Hamerton, I.; Jayawardena, K. D. G. I.; Chen, J-S.; Stolojan, V.; Ballocchi, P.; Walsh, R.; Silva, S. R. P.

2016-01-01

Carbon fibre reinforced polymers (CFRP) were introduced to the aerospace, automobile and civil engineering industries for their high strength and low weight. A key feature of CFRP is the polymer sizing - a coating applied to the surface of the carbon fibres to assist handling, improve the interfacial adhesion between fibre and polymer matrix and allow this matrix to wet-out the carbon fibres. In this paper, we introduce an alternative material to the polymer sizing, namely carbon nanotubes (CNTs) on the carbon fibres, which in addition imparts electrical and thermal functionality. High quality CNTs are grown at a high density as a result of a 35 nm aluminium interlayer which has previously been shown to minimise diffusion of the catalyst in the carbon fibre substrate. A CNT modified-CFRP show 300%, 450% and 230% improvements in the electrical conductivity on the ‘surface’, ‘through-thickness’ and ‘volume’ directions, respectively. Furthermore, through-thickness thermal conductivity calculations reveal a 107% increase. These improvements suggest the potential of a direct replacement for lightning strike solutions and to enhance the efficiency of current de-icing solutions employed in the aerospace industry. PMID:27876858

Structural properties of impact ices accreted on aircraft structures

NASA Technical Reports Server (NTRS)

Scavuzzo, R. J.; Chu, M. L.

1987-01-01

The structural properties of ice accretions formed on aircraft surfaces are studied. The overall objectives are to measure basic structural properties of impact ices and to develop finite element analytical procedures for use in the design of all deicing systems. The Icing Research Tunnel (IRT) was used to produce simulated natural ice accretion over a wide range of icing conditions. Two different test apparatus were used to measure each of the three basic mechanical properties: tensile, shear, and peeling. Data was obtained on both adhesive shear strength of impact ices and peeling forces for various icing conditions. The influences of various icing parameters such as tunnel air temperature and velocity, icing cloud drop size, material substrate, surface temperature at ice/material interface, and ice thickness were studied. A finite element analysis of the shear test apparatus was developed in order to gain more insight in the evaluation of the test data. A comparison with other investigators was made. The result shows that the adhesive shear strength of impact ice typically varies between 40 and 50 psi, with peak strength reaching 120 psi and is not dependent on the kind of substrate used, the thickness of accreted ice, and tunnel temperature below 4 C.

Multi-Functional Carbon Fibre Composites using Carbon Nanotubes as an Alternative to Polymer Sizing

NASA Astrophysics Data System (ADS)

Pozegic, T. R.; Anguita, J. V.; Hamerton, I.; Jayawardena, K. D. G. I.; Chen, J.-S.; Stolojan, V.; Ballocchi, P.; Walsh, R.; Silva, S. R. P.

2016-11-01

Carbon fibre reinforced polymers (CFRP) were introduced to the aerospace, automobile and civil engineering industries for their high strength and low weight. A key feature of CFRP is the polymer sizing - a coating applied to the surface of the carbon fibres to assist handling, improve the interfacial adhesion between fibre and polymer matrix and allow this matrix to wet-out the carbon fibres. In this paper, we introduce an alternative material to the polymer sizing, namely carbon nanotubes (CNTs) on the carbon fibres, which in addition imparts electrical and thermal functionality. High quality CNTs are grown at a high density as a result of a 35 nm aluminium interlayer which has previously been shown to minimise diffusion of the catalyst in the carbon fibre substrate. A CNT modified-CFRP show 300%, 450% and 230% improvements in the electrical conductivity on the ‘surface’, ‘through-thickness’ and ‘volume’ directions, respectively. Furthermore, through-thickness thermal conductivity calculations reveal a 107% increase. These improvements suggest the potential of a direct replacement for lightning strike solutions and to enhance the efficiency of current de-icing solutions employed in the aerospace industry.

A Study of Drop-Microstructured Surface Interactions during Dropwise Condensation with Quartz Crystal Microbalance

PubMed Central

Su, Junwei; Charmchi, Majid; Sun, Hongwei

2016-01-01

Dropwise condensation (DWC) on hydrophobic surfaces is attracting attention for its great potential in many industrial applications, such as steam power plants, water desalination, and de-icing of aerodynamic surfaces, to list a few. The direct dynamic characterization of liquid/solid interaction can significantly accelerate the progress toward a full understanding of the thermal and mass transport mechanisms during DWC processes. This work reports a novel Quartz Crystal Microbalance (QCM) based method that can quantitatively analyze the interaction between water droplets and micropillar surfaces during different condensation states such as filmwise, Wenzel, and partial Cassie states. A combined nanoimprinting lithography and chemical surface treatment approach was utilized to fabricate the micropillar based superhydrophobic and superhydrophilic surfaces on the QCM substrates. The normalized frequency shift of the QCM device together with the microscopic observation of the corresponding drop motion revealed the droplets growth and their coalescence processes and clearly demonstrated the differences between the three aforementioned condensation states. In addition, the transition between Cassie and Wenzel states was successfully captured by this method. The newly developed QCM system provides a valuable tool for the dynamic characterization of different condensation processes. PMID:27739452

Multi-Functional Carbon Fibre Composites using Carbon Nanotubes as an Alternative to Polymer Sizing.

PubMed

Pozegic, T R; Anguita, J V; Hamerton, I; Jayawardena, K D G I; Chen, J-S; Stolojan, V; Ballocchi, P; Walsh, R; Silva, S R P

2016-11-23

Carbon fibre reinforced polymers (CFRP) were introduced to the aerospace, automobile and civil engineering industries for their high strength and low weight. A key feature of CFRP is the polymer sizing - a coating applied to the surface of the carbon fibres to assist handling, improve the interfacial adhesion between fibre and polymer matrix and allow this matrix to wet-out the carbon fibres. In this paper, we introduce an alternative material to the polymer sizing, namely carbon nanotubes (CNTs) on the carbon fibres, which in addition imparts electrical and thermal functionality. High quality CNTs are grown at a high density as a result of a 35 nm aluminium interlayer which has previously been shown to minimise diffusion of the catalyst in the carbon fibre substrate. A CNT modified-CFRP show 300%, 450% and 230% improvements in the electrical conductivity on the 'surface', 'through-thickness' and 'volume' directions, respectively. Furthermore, through-thickness thermal conductivity calculations reveal a 107% increase. These improvements suggest the potential of a direct replacement for lightning strike solutions and to enhance the efficiency of current de-icing solutions employed in the aerospace industry.

The influence of carbonation process on concrete bridges and durability in Estonian practice

NASA Astrophysics Data System (ADS)

Liisma, E.; Sein, S.; Järvpõld, M.

2017-10-01

Concrete as one of the most widely used construction material in building industry, has considerable implementing in bridge engineering due to its extensive number of effective technical characteristics. However, according to exploitation environment, there are substantial factors such as aggressive liquids (e.g. deiced salts, sulfates, etc), rapid temperature alterations and the increasing rate of CO2 to take into account predicting actual retained service life of concrete structure and the need of repairmen to increase the lifespan of the bridge. According to several measuring, concentration of atmospheric CO2 is reported linearly increasing and is modeled to appear as exponential increase in the next decade. This environmental influence leads to accelerated carbonation process of concrete and brings up the importance of its potential untimely degradation mechanism. Hence, the main aim of this research is to give an analyzed overview of the carbonation depths of selection of 11 concrete bridges in Estonia built in the period of 1976-2007 and their relation with compressive strength of concrete. In addition to in situ tests, laboratory research was performed to understand natural carbonation rate and compressive strength relations of concrete.

Mechanical properties and durability of crumb rubber concrete

NASA Astrophysics Data System (ADS)

Chylík, Roman; Trtík, Tomáš; Fládr, Josef; Bílý, Petr

2017-09-01

This paper is focused on concrete with admixture of rubber powder, generally called crumb rubber concrete (CRC). The inspiration was found in Arizona, where one of the first CRCs has been created. However, Arizona has completely different climates than Central Europe. Could we use the crumb rubber concrete on construction applications in the Central European climate too? The paper evaluates the influence of the rubber powder on material characteristics and durability of CRC. CRCs with various contents of fine and coarse crumb powder were compared. The tested parameters were slump, air content, permeability, resistance of concrete to water with deicing chemicals, compressive and splitting tensile strength. The tests showed that workability, compressive strength and permeability decreased as the amount of rubber increased, but the air content increased as the rubber content increased. Photos of air voids in cement matrix from electron microscope were captured. The results of laboratory tests showed that admixture of rubber powder in concrete could have a positive impact on durability of concrete and concurrently contribute to sustainable development. Considering the lower compressive strength, CRC is recommended for use in applications where the high strength of concrete is not required.

60NiTi Intermetallic Material Evaluation for Lightweight and Corrosion Resistant Spherical Sliding Bearings for Aerospace Applications, Report on NASA-Kamatics SAA3-1288

NASA Technical Reports Server (NTRS)

Dellacorte, Christopher; Jefferson, Michael

2015-01-01

Under NASA Space Act Agreement (SAA3-1288), NASA Glenn Research Center and the Kamatics subsidiary of the Kaman Corporation conducted the experimental evaluation of spherical sliding bearings made with 60NiTi inner races. The goal of the project was to assess the feasibility of manufacturing lightweight, corrosion resistant bearings utilizing 60NiTi for aerospace and industrial applications. NASA produced the bearings in collaboration with Abbott Ball Corporation and Kamatics fabricated bearing assemblies utilizing their standard reinforced polymer liner material. The assembled bearings were tested in oscillatory motion at a load of 4.54 kN (10,000 lb), according to the requirements of the plain bearing specification SAE AS81820. Several test bearings were exposed to hydraulic fluid or aircraft deicing fluid prior to and during testing. The results show that the 60NiTi bearings exhibit tribological performance comparable to conventional stainless steel (440C) bearings. Further, exposure of 60NiTi bearings to the contaminant fluids had no apparent performance effect. It is concluded that 60NiTi is a feasible bearing material for aerospace and industrial spherical bearing applications.

Nonpoint Source Road Salt Pollution from Urban Stormwater

NASA Astrophysics Data System (ADS)

DeGaetano, S.; Walter, M. T.

2014-12-01

In colder climates, such as the Northeast, road salts are commonly applied to deice roads in order to increase pedestrian and driver safety. This study was conducted to establish the mass if NaCl entering the local aquatic systems from Cornell's campus. Using trail cameras, two typical storm water pipes (draining into Cascadilla Creek) were monitored to determine the volume of runoff on an hourly bases. Grab samples were taken three times a week obtain storm water chloride concentration. In general, the average measured salt concentration was found to be 3.61 g/L, while high precipitation events Cl- concentration spiked to levels exceeding 12 g/L (≈ 20 g/L of salt). Combining runoff volumes and salt concentration values, a mass per drainage area was calculated for each monitored pipe. Outfall #1, located just upstream from the Wilson Synchrotron Module, expelled 262,300 kg of salt over a 42-day period of data collection while Outfall#2 discharged 4160 kg during the same period. These results were averaged and then applied to the total impervious area on Cornell's campus to approximate the total mass of sodium chloride leaving campus during the period of data collection.

Lewis Rodert Receiving a Collier Trophy from President Truman

NASA Image and Video Library

1947-12-21

Lewis Rodert, then of the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory, receives the Collier Trophy from President Harry Truman for his work in the design and development of an ice prevention system for aircraft. The accumulation of ice on an aircraft had been a critical issue for years. Rodert developed a method of transferring engine heat to the wings and other vulnerable components to prevent ice buildup. Rodert began his icing investigations at Langley Memorial Aeronautical Laboratory in 1936. The NACA ordered a Lockheed 12A aircraft to be built using Rodert’s deicing system. The aircraft successfully flew through icing conditions during the following winter. Soon thereafter the military incorporated the system into a Consolidated B-24D Liberator and several other military aircraft, including a North American XB-25F. Rodert and the NACA icing program transferred to the Lewis lab in Cleveland in 1946. In Cleveland, the focus turned to the study of cloud composition and the causes of icing. Rodert’s role at Lewis diminished over the ensuing years. Rodert was honored in 1947 for his Collier Trophy at ceremonies at Langley, Ames, and then finally Lewis.

The environmental impact of the use of large wind turbines

NASA Astrophysics Data System (ADS)

Manning, P. T.

The existing data base on the environmental impact of large wind energy conversion systems (WECS) is explored. The maximum blade throw distance has been calculated at 850 m, with a 5% probability of more than 300 m. Good design and inspection procedures reduce the risk. Ice throw can be prevented by aircraft deicing techniques, but detectors are still necessary. TV interference is ameliorated by the use of composite blades and directional antennas, by relocating the nearst transmission or relay station, or by introduction of cable TV. Microwave transmission effects can be avoided by careful siting of WECS in a favorable line of sight whenever within 1 km of a transmitter. Visual impact studies have produced few adverse opinions. Noise has not proved an intractable problem, although 30 dB levels have been exceeded 2100 m downwind of the Mod 2 WECS. Further studies are necessary on the effects of heightened ground turbulence produced by large WECS. It is expected that few birds will be harmed by slowly rotating blades in the birds' natural domain, a projection confirmed by sporadic studies. Finally, aircraft collisions are regarded as unlikely and actual land use, mostly confined to rural areas, is minimal.

Icing flight research: Aerodynamic effects of ice and ice shape documentation with stereo photography

NASA Technical Reports Server (NTRS)

Mikkelsen, K. L.; Mcknight, R. C.; Ranaudo, R. J.; Perkins, P. J., Jr.

1985-01-01

Aircraft icing flight research was performed in natural icing conditions. A data base consisting of icing cloud measurements, ice shapes, and aerodynamic measurements is being developed. During research icing encounters the icing cloud was continuously measured. After the encounter, the ice accretion shapes on the wing were documented with a stereo camera system. The increase in wing section drag was measured with a wake survey probe. The overall aircraft performance loss in terms of lift and drag coefficient changes was obtained by steady level speed/power measurements. Selective deicing of the airframe components was performed to determine their contributions to the total drag increase. Engine out capability in terms of power available was analyzed for the iced aircraft. It was shown that the stereo photography system can be used to document ice shapes in flight and that the wake survey probe can measure increases in wing section drag caused by ice. On one flight, the wing section drag coefficient (c sub d) increased approximately 120 percent over the uniced baseline at an aircraft angle of attack of 6 deg. On another flight, the aircraft darg coefficient (c sub d) increased by 75 percent over the uniced baseline at an aircraft lift coefficient (C sub d) of 0.5.

Icing flight research - Aerodynamic effects of ice and ice shape documentation with stereo photography

NASA Technical Reports Server (NTRS)

Mikkelsen, K. L.; Mcknight, R. C.; Ranaudo, R. J.; Perkins, P. J., Jr.

1985-01-01

Aircraft icing flight research was performed in natural icing conditions. A data base consisting of icing cloud measurements, ice shapes, and aerodynamic measurements is being developed. During research icing encounters the icing cloud was continuously measured. After the encounter, the ice accretion shapes on the wing were documented with a stereo camera system. The increase in wing section drag was measured with a wake survey probe. The overall aircraft performance loss in terms of lift and drag coefficient changes were obtained by steady level speed/power measurements. Selective deicing of the airframe components was performed to determine their contributions to the total drag increase. Engine out capability in terms of power available was analyzed for the iced aircraft. It was shown that the stereo photography system can be used to document ice shapes in flight and that the wake survey probe can measure increases in wing section drag caused by ice. On one flight, the wing section drag coefficient (c sub d) increased approximately 120 percent over the uniced baseline at an aircraft angle of attack of 6 deg. On another flight, the aircraft drag coefficient (c sub d) increased by 75 percent over the uniced baseline at an aircraft lift coefficient (c sub d) of 0.5.

Embedded chloride detectors for roadways and bridges

NASA Astrophysics Data System (ADS)

Fuhr, Peter L.; Huston, Dryver R.; McPadden, Adam P.; Cauley, Robert F.

1996-04-01

The problems associated with the application of chloride-based deicing agents to roadways and specifically bridges include chemical pollution and accelerated corrosion of strength members (especially rebar) within the structure. In many instances, local ordinances are attempting to force state agencies to reduce, if not eliminate, the use of these chlorides (typically at the cost of increased driving hazards). With respect to the corrosion aspects of chloride application, cracks that occur in the roadway/bridge pavement allow water to seep into the pavement carrying the chloride to the rebar with the resultant increase in corrosion. In response to this problem, particularly in high roadsalt usage areas, a chloride/water impermeable membrane is placed above the rebar matrix so if/when roadway cracking occurs, the roadsalts won't be able to damage the rebar. Such a membrane is costly -- and the question of its in-service performance is questionable. In a joint effort between the University of Vermont and the Vermont Agency of Transportation, we are developing fiber optic chloride detectors which are capable of being embedded into the rebar-concrete roadway under this membrane. The sensing mechanism relies on spectroscopic analysis of a chemical reaction of chloride and reagents (which have been coated onto the ends of fibers). Laboratory results of these detectors and a usable system configuration are presented.

Water ingress detection in honeycomb sandwich panels by passive infrared thermography using a high-resolution thermal imaging camera

NASA Astrophysics Data System (ADS)

Ibarra-Castanedo, C.; Brault, L.; Marcotte, F.; Genest, M.; Farley, V.; Maldague, X.

2012-06-01

Water ingress in honeycomb structures is of great concern for the civil and military aerospace industries. Pressure and temperature variations during take-off and landing produce considerable stress on aircraft structures, promoting moisture ingress (by diffusion through fibers or by direct ingress through voids, cracks or unsealed joints) into the core. The presence of water (or other fluids such as kerosene, hydraulic fluid and de-icing agents) in any of its forms (gas vapor, liquid or ice) promotes corrosion, cell breakage, and induce composite layer delaminations and skin disbonds. In this study, testing specimens were produced from unserviceable parts from military aircraft. In order to simulate atmospheric conditions during landing, selected core areas were filled with measured quantities of water and then frozen in a cold chamber. The specimens were then removed from the chamber and monitored for over 20 minutes as they warm up using a cooled high-resolution infrared camera. Results have shown that detection and quantification of water ingress on honeycomb sandwich structures by passive infrared thermography is possible using a HD mid-wave infrared cameras for volumes of water as low as 0.2 ml and from a distance as far as 20 m from the target.

Environmental and Human Health Impacts of Spreading Oil and Gas Wastewater on Roads.

PubMed

Tasker, T L; Burgos, W D; Piotrowski, P; Castillo-Meza, L; Blewett, T A; Ganow, K B; Stallworth, A; Delompré, P L M; Goss, G G; Fowler, L B; Vanden Heuvel, J P; Dorman, F; Warner, N R

2018-06-19

Thirteen states in the United States allow the spreading of O&G wastewaters on roads for deicing or dust suppression. In this study, the potential environmental and human health impacts of this practice are evaluated. Analyses of O&G wastewaters spread on roads in the northeastern, U.S. show that these wastewaters have salt, radioactivity, and organic contaminant concentrations often many times above drinking water standards. Bioassays also indicated that these wastewaters contain organic micropollutants that affected signaling pathways consistent with xenobiotic metabolism and caused toxicity to aquatic organisms like Daphnia magna. The potential toxicity of these wastewaters is a concern as lab experiments demonstrated that nearly all of the metals from these wastewaters leach from roads after rain events, likely reaching ground and surface water. Release of a known carcinogen (e.g., radium) from roads treated with O&G wastewaters has been largely ignored. In Pennsylvania from 2008 to 2014, spreading O&G wastewater on roads released over 4 times more radium to the environment (320 millicuries) than O&G wastewater treatment facilities and 200 times more radium than spill events. Currently, state-by-state regulations do not require radium analyses prior to treating roads with O&G wastewaters. Methods for reducing the potential impacts of spreading O&G wastewaters on roads are discussed.

Fabry-Perot sensors for the monitoring of FRP reinforced bridge decks

NASA Astrophysics Data System (ADS)

Benmokrane, Brahim; Quirion, Marco; El-Salakawy, Ehab; Debaiky, Ahmed S.; Lackey, Tom

2004-07-01

The extensive use of deicing salts in Canada during winter times is identified as the main reason behind the deterioration of highway bridges and parking garages. To fight this infrastructure crisis, Fibre Reinforced Polymers (FRP) has become a very attractive alternative to traditional reinforcing steel due to their non-corrosive nature and light weight. The replacement of steel with Glass FRP bars in bridge deck slabs has been extensively researched in the last few years. This paper presents the first efforts to implement these bars in two highway bridges in Quebec, Canada, and Vermont, USA. These projects are aimed to prove the feasibility of using GFRP bars in bridge construction. GFRP bars were used as reinforcement for parts of the deck slabs in the two bridges while traditional steel was used in the remaining parts. Fibre Optic Sensors (FOS) were used to measure strains in the concrete, reinforcing bars and steel girders. The sensors were surface mounted on the bars or steel girders using standard glue, or embedded in concrete. Static and dynamic testing of the bridges was done using loaded trucks placed for maximum stresses. The design, construction, testing, and results obtained from the bridges are briefly outlined in this paper. The results indicated the accuracy of the sensors and their feasibility for bridge construction and remote monitoring.

The Effects of Temperature, Humidity and Aircraft Fluid Exposure on T800H/3900-2 Composites Bonded with AF-555M Adhesive

NASA Technical Reports Server (NTRS)

Miner, Gilda A.; Hou, Tan-Hung; Lowther, Sharon E.; Thibeault, Sheila A.; Connell, John W.; Blasini, Sheila Roman

2010-01-01

Fiber reinforced resin matrix composites and structural adhesives have found increased usage on commercial and military aircraft in recent years. Due to the lack of service history of these relatively new material systems, their long-term aging performance has not been well established. In this study, single lap shear specimens (SLS) were fabricated by secondary bonding of Scotch-Weld(TradeMark) AF-555M between pre-cured adherends comprised of T800H/3900-2 uni-directional laminates. The adherends were co-cured with wet peel-ply for surface preparation. Each bond-line of the SLS specimen was measured to determine thickness and inspected visually using an optical microscope for voids. A three-year environmental aging plan for the SLS specimens at 82 C (180 F) and 85% relative humidity was initiated. SLS strengths were measured for both controls and aged specimens at room temperature and 82 C. The effect of this exposure on lap shear strength and failure modes to date is reported. In addition, the effects of water, saline water, deicing fluid, JP-5 jet fuel and hydraulic fluid on both the composite material and the adhesive bonds were investigated. The up to date results on the effects of these exposures will be discussed.

Dynamic Impacts of Water Droplets onto Icephobic Soft Surfaces at High Weber Numbers

NASA Astrophysics Data System (ADS)

Ma, Liqun; Liu, Yang; Hu, Hui; Wang, Wei; Kota, Arun

2017-11-01

An experimental investigation was performed to examine the effects of the stiffness of icephobic soft PDMS materials on the impact dynamics of water drops at high weber numbers pertinent to aircraft icing phenomena. The experimental study was performed in the Icing Research Tunnel available at Iowa State University (ISU-IRT). During the experiments, both the shear modulus of the soft PDMS surface and the Weber numbers of the impinging water droplets are controlled for the comparative study. While the shear modulus of the soft PDMS surface was changed by tuning the recipes to make the PDMS materials, the Weber number of the impinging water droplets was altered by adjusting the airflow speed in the wind tunnel. A suite of advanced flow diagnostic techniques, which include high-speed photographic imaging, digital image projection (DIP), and infrared (IR) imaging thermometry, were used to quantify the transient behavior of water droplet impingement, unsteady heat transfer and dynamic ice accreting process over the icephobic soft airfoil surfaces. The findings derived from the icing physics studies can be used to improve current icing accretion models for more accurate prediction of ice formation and accretion on aircraft wings and to develop effective anti-/deicing strategies for safer and more efficient operation of aircraft in cold weather.

New non-stick expoxy-silicone water-based coatings part 1: Physical and surface properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garti, N.; Smith, J.

In search for tomorrow`s technology for water-based coating, Decora Manufacturing and The Hebrew University of Jerusalem, have initiated an intensive research program for designing, developing and manufacturing new coatings based on cross-linked, room temperature-cured silicone-expoxy resins. The new water-borne coatings have most exciting characteristics such as: non-stick properties, effective release, high lubricity, corrosion protection and abrasion resistance. The coatings are environmentally-friendly and easy to use. These coatings are ideal for marine, agricultural, industrial and maintenance applications. This paper brings quantitative measurements related to the dispersion technology (particle size, stability, shelf-life), to the non-stick properties (deicing, low surface energy, easy-release andmore » non-stick), lubricity, adhesion to substrates, viscosity, dynamic and static friction coefficients and environmental impact (low VOC, non-toxicity, low-leaching). The coating was tested in various industrial coating systems and was found to exhibit excellent non-stick and release properties. Special attention was given to Zebra Mussels, Quagga Mussels and other bacterial and algeal bioforms. The coating proved to be efficient as foul-release coating with very low biofouling adhesion. The low adhesion applied to many other substances in which foul-release means easy-clean and low-wear.« less

A numerical simulation of the full two-dimensional electrothermal de-icer pad. Ph.D. Thesis Final Report

NASA Technical Reports Server (NTRS)

Masiulaniec, Konstanty C.

1988-01-01

The ability to predict the time-temperature history of electrothermal de-icer pads is important in the subsequent design of improved and more efficient versions. These de-icer pads are installed near the surface of aircraft components, for the specific purpose of removing accreted ice. The proposed numerical model can incorporate the full 2-D geometry through a section of a region (i.e., section of an airfoil), that current 1-D numerical codes are unable to do. Thus, the effects of irregular layers, curvature, etc., can now be accounted for in the thermal transients. Each layer in the actual geometry is mapped via a body-fitted coordinate transformation into uniform, rectangular computational grids. The relevant heat transfer equations are transformed and discretized. To model the phase change that might occur in any accreted ice, in an enthalpy formulation the phase change equations are likewise transformed and discretized. The code developed was tested against numerous classical numerical solutions, as well as against experimental de-icing data on a UH1H rotor blade obtained from the NASA Lewis Research Center. The excellent comparisons obtained show that this code can be a useful tool in predicting the performance of current de-icer models, as well as in the designing of future models.

Relating road salt to exceedances of the water quality standard for chloride in New Hampshire streams.

PubMed

Trowbridge, Philip R; Kahl, J Steve; Sassan, Dari A; Heath, Douglas L; Walsh, Edward M

2010-07-01

Six watersheds in New Hampshire were studied to determine the effects of road salt on stream water quality. Specific conductance in streams was monitored every 15 min for one year using dataloggers. Chloride concentrations were calculated from specific conductance using empirical relationships. Stream chloride concentrations were directly correlated with development in the watersheds and were inversely related to streamflow. Exceedances of the EPA water quality standard for chloride were detected in the four watersheds with the most development. The number of exceedances during a year was linearly related to the annual average concentration of chloride. Exceedances of the water quality standard were not predicted for streams with annual average concentrations less than 102 mg L(-1). Chloride was imported into three of the watersheds at rates ranging from 45 to 98 Mg Cl km(-2) yr(-1). Ninety-one percent of the chloride imported was road salt for deicing roadways and parking lots. A simple, mass balance equation was shown to predict annual average chloride concentrations from streamflow and chloride import rates to the watershed. This equation, combined with the apparent threshold for exceedances of the water quality standard, can be used for screening-level TMDLs for road salt in impaired watersheds.

Biogeochemical role of magnetite in urban soils (Review of publications)

NASA Astrophysics Data System (ADS)

Vodyanitskii, Yu. N.

2013-03-01

The surface horizons of urban soils are enriched in technogenic magnetite Fe3O4 accumulated from emissions. Its content there reaches 3-4% and more, whereas it does not exceed 0.1% in the back-ground soils. In urban soils, large spherical magnetite particles of pseudo-single-domain and multidomain fabric predominate; the cavities in magnetic spherules decrease their chemical stability and increase their reactivity. Magnetite is most often destroyed in urban soils due to complexing; its destruction may be initiated by mineral salts entering the soil with deicing mixtures and by organic acids excreted by roots (e.g., by oxalic acid). The high solubility of magnetite with ammonium oxalate should be taken into account when using Tamm's reagent for the analysis of urban soils. Magnetite is a mineral carrier of some heavy metals. Therefore, its content (as determined from the magnetic susceptibility) serves as an indirect index of soil pollution. In addition, magnetite may affect many soil properties as a reducer and sorbent. It adsorbs phosphorus thus preventing the penetration of this nutrient into rivers and lakes. Magnetite also oxidizes Cl-containing aliphatic hydrocarbons and purifies the soil. Although magnetite enters urban soils as a pollutant, its influence on the soil properties cannot be unambiguously judged as only negative.

Recent trends in digital halftoning

NASA Astrophysics Data System (ADS)

Delabastita, Paul A.

1997-02-01

Screening is perhaps the oldest form of image processing. The word refers to the mechanical cross line screens that were used at the beginning of this century for the purpose of photomechanical reproduction. Later on, these mechanical screens were replaced by photographic contact screens that enabled significantly improved process control. In the early eighties, the optical screening on graphic arts scanners was replaced by a combination of laser optics and electronic screening. The algorithms, however, were still digital implementations of the original optical methods. The printing needs in the fast growing computer and software industry gave birth to a number of alternative printing technologies such as electrophotographic and inkjet printing. Originally these deices were only designed for printing text, but soon people started experimenting and using them for printing images. The relatively low spatial resolutions of these new devices however made complete review of 'the screening issue' necessary to achieve an acceptable image quality. In this paper a number of recent developments in screening technology are summarized. Special attention is given to the interaction that exists between a halftone screen and the printing devices on which they are rendered including the color mixing behavior. Improved screening techniques are presented that take advantage of modeling the physical behavior of the rendering device.

Dynamics of Physical and Physicochemical Properties of Urban Soils under the Effect of Ice-Melting Salts

NASA Astrophysics Data System (ADS)

Azovtseva, N. A.; Smagin, A. V.

2018-01-01

Physical (water content, density, and air and water regimes) and physicochemical (electrical conductivity, pH, and SAR) properties of urban soils were investigated on test plots of Moscow to evaluate their dynamics under anthropogenic impact. The wilting point and the dependence of the capillary-sorption and total water potentials of the soil water content were determined in laboratory experiments with natural and artificially saline soil samples to evaluate the effect of salt antifreeze substances on water availability for plants under conditions of active application of deicing reagents. Seasonal dynamics of these parameters were investigated. It was found that electrolytes display a steady tendency for the accumulation and redistribution in the root zone rather than for their deep leaching despite humid climatic conditions in Moscow megalopolis. In summer, regular droughts result in drying of the root zone to critical values and to the concentration of electrolytes up to the values that make the total water potential of soil unsuitable for water uptake by roots. The key factor of soil degradation under the impact of electrolytes is the soil dispersity: the finer the texture, the higher the soil salinization and solonetzicity and the stronger irreversible changes in the soil water retention capacity and physical properties.

Migration of alternative de-icers in unsaturated zone of aquifers--in vitro study.

PubMed

Hellstén, P; Nystén, T

2003-01-01

The migration of organic de-icers in the shallow aquifers typical in Finland is not well known and we need to find solutions to minimise the negative impacts of de-icing on groundwater quality. The objective of the MIDAS project is to find de-icers which have the least harmful impacts on groundwater quality. Migration of sodium chloride as a tracer and five alternative de-icers in aquifers was studied. The alternative de-icers were calcium chloride, magnesium chloride, calcium-magnesium-acetate, potassium acetate and potassium formate. The research consists of leaching of heavy metals from roadsides in the area of Highway 1 in southern Finland; an in vitro study, which represented the full length of winter at low temperatures; and the subsequent on-going field research in south-eastern Finland. So far, in our studies potassium formate caused fewer changes to the quality of the infiltrated water than the chlorides and acetates. After finishing the on-going research the results will be used to choose a preferred de-icer from the existing chemicals and for the development of new less harmful de-icers. The information will be used mainly in Scandinavia and North America where the hydrogeological conditions are similar to those in Finland.

Thin, Light, Flexible Heaters Save Time and Energy

NASA Technical Reports Server (NTRS)

2007-01-01

The Icing Branch at NASA's Glenn Research Center uses the Center's Icing Research Tunnel (IRT) and Icing Research Aircraft to research methods for evaluating and simulating the growth of ice on aircraft, the effects that ice may have on aircraft in flight, and the development and effectiveness of various ice protection and detection systems. EGC Enterprises Inc. (EGC), of Chardon, Ohio, used the IRT to develop thermoelectric thin-film heater technology to address in-flight icing on aircraft wings. Working with researchers at Glenn and the original equipment manufacturers of aircraft parts, the company tested various thin, flexible, durable, lightweight, and efficient heaters. Development yielded a thin-film heater technology that can be used in many applications in addition to being an effective deicer for aircraft. This new thermoelectric heater was dubbed the QoFoil Rapid Response Thin-Film Heater, or QoFoil, for short. The product meets all criteria for in-flight use and promises great advances in thin-film, rapid response heater technology for a broad range of industrial applications. Primary advantages include time savings, increased efficiency, and improved temperature uniformity. In addition to wing deicing, EGC has begun looking at the material's usefulness for applications including cooking griddles, small cabinet heaters, and several laboratory uses.

Interactions between chloride and cement-paste materials.

PubMed

Barberon, Fabien; Baroghel-Bouny, Véronique; Zanni, Hélène; Bresson, Bruno; d'Espinose de la Caillerie, Jean-Baptiste; Malosse, Lucie; Gan, Zehong

2005-02-01

The durability of cement-based materials with respect to exterior aggressions is one of the current priorities in civil engineering. Depending on their use, the cement-based materials can be exposed to different types of aggressive environments. For instance, damages to concrete structures in contact with a saline environment (sea water on bridges, deicing salts on roads, etc.) are of utmost importance. Upon exposure to saline water, Cl- ions penetrate into the structures and subsequently lead to reinforcement corrosion. Chloride attack is often combined with other aggressive influences such as temperature (e.g., freezing) or the ingress of other ions (e.g., sulfates in sea water). We therefore aim to explore the effect of sodium chloride (NaCl) on the structural chemistry of cement paste. Existing studies about reinforcement corrosion by chloride have focused on the penetration of Cl- ions and the comparison between "free" ions (water-soluble ions) and bound ones. However, little is known about the fixation mechanisms, the localization of Cl in the cement matrix and the structural interaction between Cl and the silicate and aluminate hydrate phases present in cement paste. We present here results of a multinuclear nuclear magnetic resonance study on the fixation of chloride in the hydration products and the characterization of new phases potentially appearing due to chloride ingress.

Strain characterization of embedded aerospace smart materials using shearography

NASA Astrophysics Data System (ADS)

Anisimov, Andrei G.; Müller, Bernhard; Sinke, Jos; Groves, Roger M.

2015-04-01

The development of smart materials for embedding in aerospace composites provides enhanced functionality for future aircraft structures. Critical flight conditions like icing of the leading edges can affect the aircraft functionality and controllability. Hence, anti-icing and de-icing capabilities are used. In case of leading edges made of fibre metal laminates heater elements can be embedded between composite layers. However this local heating causes strains and stresses in the structure due to the different thermal expansion coefficients of the different laminated materials. In order to characterize the structural behaviour during thermal loading full-field strain and shape measurement can be used. In this research, a shearography instrument with three spatially-distributed shearing cameras is used to measure surface displacement gradients which give a quantitative estimation of the in- and out-of-plane surface strain components. For the experimental part, two GLARE (Glass Laminate Aluminum Reinforced Epoxy) specimens with six different embedded copper heater elements were manufactured: two copper mesh shapes (straight and S-shape), three connection techniques (soldered, spot welded and overlapped) and one straight heater element with delaminations. The surface strain behaviour of the specimens due to thermal loading was measured and analysed. The comparison of the connection techniques of heater element parts showed that the overlapped connection has the smallest effect on the surface strain distribution. Furthermore, the possibility of defect detection and defect depth characterisation close to the heater elements was also investigated.

Impact of urban development on the chemical composition of ground water in a fen-wetland complex

USGS Publications Warehouse

Panno, S.V.; Nuzzo, V.A.; Cartwright, K.; Hensel, B.R.; Krapac, I.G.

1999-01-01

A 15-month-long hydrogeologic investigation of a fen-wetland complex in northeastern Illinois, USA indicated the encroachment of ground-water-borne anthropogenic contaminants into two of three high quality fens. Ground-water flow directions and chemical evidence indicated that plumes of ground water with anomalously large concentrations of Na+ and Cl- originated from a private septic system and from rock salt spread on an adjacent road. The contamination, in turn, had an adverse effect on fen vegetation; within the plumes, diverse vegetation was replaced by the more salt-tolerant narrow-leaf cattail (Typha angustifolia). Ground water of the third fen contained large concentrations of SO42- as high as 516 mg/L. The SO42- anomaly was observed on a transient and/or seasonal basis in the fen ground water and in an adjacent marsh and pond. Isotopically light ??34S values in these waters indicated that the addition of SO42- resulted from the oxidation of pyrite within underlying peat and/or pyritic gravel. However, the large SO42- concentrations had no discernible effect on fen vegetation. The results of this investigation indicate how easily construction of houses with private septic systems and deicing agents from roadway maintenance can contaminate fen ground water with relatively large concentrations of Na+ and Cl-, resulting in a significant loss of biodiversity in fens.

River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons

USGS Publications Warehouse

Corsi, Steven R.; De Cicco, Laura A.; Lutz, Michelle A.; Hirsch, Robert M.

2014-01-01

Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006–2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period.

Bell P-39 in the Icing Research Tunnel

NASA Image and Video Library

1944-11-21

A Bell P-39 Airacobra in the NACA Aircraft Engine Research Laboratory’s Icing Research Tunnel for a propeller deicing study. The tunnel, which began operation in June 1944, was built to study the formation of ice on aircraft surfaces and methods of preventing or eradicating that ice. Ice buildup adds extra weight to aircraft, effects aerodynamics, and sometimes blocks airflow through engines. NACA design engineers added the Icing Research Tunnel to the new AERL’s original layout to take advantage of the massive refrigeration system being constructed for the Altitude Wind Tunnel. The Icing Research Tunnel is a closed-loop atmospheric wind tunnel with a 6- by 9-foot test section. The tunnel can produce speeds up to 300 miles per hour and temperatures from about 30 to –45⁰ F. During World War II AERL researchers analyzed different ice protection systems for propeller, engine inlets, antennae, and wings in the icing tunnel. The P-39 was a vital low-altitude pursuit aircraft of the US during the war. NACA investigators investigated several methods of preventing ice buildup on the P-39’s propeller, including the use of internal and external electrical heaters, alcohol, and hot gases. They found that continual heating of the blades expended more energy than the aircraft could supply, so studies focused on intermittent heating. The results of the wind tunnel investigations were then compared to actual flight tests on aircraft.

Vultee YA–31C Vengeance at the NACA

NASA Image and Video Library

1945-03-21

A Bell P-39 Airacobra in the NACA Aircraft Engine Research Laboratory’s Icing Research Tunnel for a propeller deicing study. The tunnel, which began operation in June 1944, was built to study the formation of ice on aircraft surfaces and methods of preventing or eradicating that ice. Ice buildup adds extra weight to aircraft, effects aerodynamics, and sometimes blocks airflow through engines. NACA design engineers added the Icing Research Tunnel to the new AERL’s original layout to take advantage of the massive refrigeration system being constructed for the Altitude Wind Tunnel. The Icing Research Tunnel is a closed-loop atmospheric wind tunnel with a 6- by 9-foot test section. The tunnel can produce speeds up to 300 miles per hour and temperatures from about 30 to -45⁰ F. During World War II AERL researchers analyzed different ice protection systems for propeller, engine inlets, antennae, and wings in the icing tunnel. The P-39 was a vital low-altitude pursuit aircraft of the US during the war. NACA investigators investigated several methods of preventing ice buildup on the P-39’s propeller, including the use of internal and external electrical heaters, alcohol, and hot gases. They found that continual heating of the blades expended more energy than the aircraft could supply, so studies focused on intermittent heating. The results of the wind tunnel investigations were then compared to actual flight tests on aircraft.

Design of ice-free nanostructured surfaces based on repulsion of impacting water droplets.

PubMed

Mishchenko, Lidiya; Hatton, Benjamin; Bahadur, Vaibhav; Taylor, J Ashley; Krupenkin, Tom; Aizenberg, Joanna

2010-12-28

Materials that control ice accumulation are important to aircraft efficiency, highway and powerline maintenance, and building construction. Most current deicing systems include either physical or chemical removal of ice, both energy and resource-intensive. A more desirable approach would be to prevent ice formation rather than to fight its build-up. Much attention has been given recently to freezing of static water droplets resting on supercooled surfaces. Ice accretion, however, begins with the droplet/substrate collision followed by freezing. Here we focus on the behavior of dynamic droplets impacting supercooled nano- and microstructured surfaces. Detailed experimental analysis of the temperature-dependent droplet/surface interaction shows that highly ordered superhydrophobic materials can be designed to remain entirely ice-free down to ca. -25 to -30 °C, due to their ability to repel impacting water before ice nucleation occurs. Ice accumulated below these temperatures can be easily removed. Factors contributing to droplet retraction, pinning and freezing are addressed by combining classical nucleation theory with heat transfer and wetting dynamics, forming the foundation for the development of rationally designed ice-preventive materials. In particular, we emphasize the potential of hydrophobic polymeric coatings bearing closed-cell surface microstructures for their improved mechanical and pressure stability, amenability to facile replication and large-scale fabrication, and opportunities for greater tuning of their material and chemical properties.

The Influence of Calcium Chloride Deicing Salt on Phase Changes and Damage Development in Cementitious Materials.

PubMed

Farnam, Yaghoob; Dick, Sarah; Wiese, Andrew; Davis, Jeffrey; Bentz, Dale; Weiss, Jason

2015-11-01

The conventional CaCl 2 -H 2 O phase diagram is often used to describe how calcium chloride behaves when it is used on a concrete pavement undergoing freeze-thaw damage. However, the chemistry of the concrete can alter the appropriateness of using the CaCl 2 -H 2 O phase diagram. This study shows that the Ca(OH) 2 present in a hydrated portland cement can interact with CaCl 2 solution creating a behavior that is similar to that observed in isoplethal sections of a ternary phase diagram for a Ca(OH) 2 -CaCl 2 -H 2 O system. As such, it is suggested that such isoplethal sections provide a reasonable model that can be used to describe the behavior of concrete exposed to CaCl 2 solution as the temperature changes. Specifically, the Ca(OH) 2 can react with CaCl 2 and H 2 O resulting in the formation of calcium oxychloride. The formation of the calcium oxychloride is expansive and can produce damage in concrete at temperatures above freezing. Its formation can also cause a significant decrease in fluid ingress into concrete. For solutions with CaCl 2 concentrations greater than about 11.3 % (by mass), it is found that calcium oxychloride forms rapidly and is stable at room temperature (23 °C).

Water-quality trends in New England rivers during the 20th century

USGS Publications Warehouse

Robinson, Keith W.; Campbell, Jean P.; Jaworski, Norbert A.

2003-01-01

Water-quality data from the Merrimack, Blackstone, and Connecticut Rivers in New England during parts of the 20th century were examined for trends in concentrations of sulfate, chloride, residue upon evaporation, nitrate, and total phosphorus. The concentrations of all five of these constituents show statistically significant trends during the century. Annual concentrations of sulfate and total phosphorus decreased during the second half of the century, whereas annual concentrations of nitrate, chloride, and residues increased throughout the century. In the Merrimack River, annual chloride concentrations increased by an order of magnitude. Annual nitrate concentrations also increased by an order of magnitude in the Merrimack and Connecticut Rivers. These changes in the water quality probably are related to changing human activities. Most notable is the relation between increasing use of road de-icing salts and chloride concentrations in rivers. In addition, changes in concentrations of nitrate and phosphorus probably are related to agricultural use of nitrogen and phosphorus fertilizers. For all the water-quality constituents assessed, concentrations were greatest in the Blackstone River. The Blackstone River Basin is smaller and more highly urbanized than the other basins studied. Data-collection programs that span multiple decades can provide valuable insight on the effects of changing human population and societal activities on the water quality of rivers. This study was done as part of the U.S. Geological Survey's National Water-Quality Assessment Program.

The Influence of Calcium Chloride Deicing Salt on Phase Changes and Damage Development in Cementitious Materials

PubMed Central

Farnam, Yaghoob; Dick, Sarah; Wiese, Andrew; Davis, Jeffrey; Bentz, Dale; Weiss, Jason

2015-01-01

The conventional CaCl2-H2O phase diagram is often used to describe how calcium chloride behaves when it is used on a concrete pavement undergoing freeze-thaw damage. However, the chemistry of the concrete can alter the appropriateness of using the CaCl2-H2O phase diagram. This study shows that the Ca(OH)2 present in a hydrated portland cement can interact with CaCl2 solution creating a behavior that is similar to that observed in isoplethal sections of a ternary phase diagram for a Ca(OH)2-CaCl2-H2O system. As such, it is suggested that such isoplethal sections provide a reasonable model that can be used to describe the behavior of concrete exposed to CaCl2 solution as the temperature changes. Specifically, the Ca(OH)2 can react with CaCl2 and H2O resulting in the formation of calcium oxychloride. The formation of the calcium oxychloride is expansive and can produce damage in concrete at temperatures above freezing. Its formation can also cause a significant decrease in fluid ingress into concrete. For solutions with CaCl2 concentrations greater than about 11.3 % (by mass), it is found that calcium oxychloride forms rapidly and is stable at room temperature (23 °C). PMID:26692655

High throughput laser texturing of super-hydrophobic surfaces on steel

NASA Astrophysics Data System (ADS)

Gemini, Laura; Faucon, Marc; Romoli, Luca; Kling, Rainer

2017-03-01

Super-hydrophobic surfaces are nowadays of primary interest in several application fields, as for de-icing devices in the automotive and aerospace industries. In this context, laser surface texturing has widely demonstrated to be an easy one-step method to produce super-hydrophobic surfaces on several materials. In this work, a high average power (up to 40W), high repetition-rate (up to 1MHz), femtosecond infrared laser was employed to produce super-hydrophobic surfaces on 316L steel. The set of process and laser parameters for which the super-hydrophobic behavior is optimized, was obtained by varying the laser energy and repetition rate. The morphology of the textured surfaces was firstly analyzed by SEM and confocal microscope analyses. The contact angle was measured over time in order to investigate the effect of air environment on the hydrophobic properties and define the period of time necessary for the super-hydrophobic properties to stabilize. An investigation on the effect of after-processing cleaning solvents on the CA evolution was carried to assess the influence of the after-processing sample handling on the CA evaluation. Results show that the highest values of contact angle, that is the best hydrophobic behavior, are obtained at high repetition rate and low energy, this way opening up a promising scenario in terms of upscaling for reducing the overall process takt-time.

Recovery of salts from ion-exchange regeneration streams by a coupled nanofiltration-membrane distillation process.

PubMed

Jiříček, Tomáš; De Schepper, Wim; Lederer, Tomáš; Cauwenberg, Peter; Genné, Inge

2015-01-01

Ion-exchange tap water demineralization for process water preparation results in a saline regeneration wastewater (20-100 mS cm(-1)) that is increasingly problematic in view of discharge. A coupled nanofiltration-membrane distillation (NF-MD) process is evaluated for the recovery of water and sodium chloride from this wastewater. NF-MD treatment of mixed regeneration wastewater is compared to NF-MD treatment of separate anion- and cation-regenerate fractions. NF on mixed regeneration wastewater results in a higher flux (30 L m(-2) h(-1) at 7 bar) compared to NF on the separate fractions (6-9 L m(-2) h(-1) at 30 bar). NF permeate recovery is strongly limited by scaling (50% for separate and 60% for mixed, respectively). Physical signs of scaling were found during MD treatment of the NF permeates but did not result in flux decline for mixed regeneration wastewater. Final salt composition is expected to qualify as a road de-icing salt. NF-MD is an economically viable alternative compared to external disposal of wastewater for larger-scale installations (1.4 versus 2.5 euro m(-3) produced demineralized water for a 10 m3 regenerate per day plant). The cost benefits of water re-use and salt recuperation are small when compared to total treatment costs for mixed regenerate wastewater.

River chloride trends in snow-affected urban watersheds: increasing concentrations outpace urban growth rate and are common among all seasons.

PubMed

Corsi, Steven R; De Cicco, Laura A; Lutz, Michelle A; Hirsch, Robert M

2015-03-01

Chloride concentrations in northern U.S. included in this study have increased substantially over time with average concentrations approximately doubling from 1990 to 2011, outpacing the rate of urbanization in the northern U.S. Historical data were examined for 30 monitoring sites on 19 streams that had chloride concentration and flow records of 18 to 49 years. Chloride concentrations in most studied streams increased in all seasons (13 of 19 in all seasons; 16 of 19 during winter); maximum concentrations occurred during winter. Increasing concentrations during non-deicing periods suggest that chloride was stored in hydrologic reservoirs, such as the shallow groundwater system, during the winter and slowly released in baseflow throughout the year. Streamflow dependency was also observed with chloride concentrations increasing as streamflow decreased, a result of dilution during rainfall- and snowmelt-induced high-flow periods. The influence of chloride on aquatic life increased with time; 29% of sites studied exceeded the concentration for the USEPA chronic water quality criteria of 230 mg/L by an average of more than 100 individual days per year during 2006-2011. The rapid rate of chloride concentration increase in these streams is likely due to a combination of possible increased road salt application rates, increased baseline concentrations, and greater snowfall in the Midwestern U.S. during the latter portion of the study period. Published by Elsevier B.V.

Natural and enhanced biodegradation of propylene glycol in airport soil.

PubMed

Toscano, Giuseppe; Colarieti, M Letizia; Anton, Attila; Greco, Guido; Biró, Borbála

2014-01-01

Aircraft de-icing fluids (ADF) are a source of water and soil pollution in airport sites. Propylene glycol (PG) is a main component in several commercial formulations of ADFs. Even though PG is biodegradable in soil, seasonal overloads may result in occasional groundwater contamination. Feasibility studies for the biostimulation of PG degradation in soil have been carried out in soil slurries, soil microcosms and enrichment cultures with and without the addition of nutrients (N and P sources, oligoelements), alternative electron acceptors (nitrate, oxygen releasing compounds) and adsorbents (activated carbon). Soil samples have been taken from the contaminated area of Gardermoen Airport Oslo. Under aerobic conditions and in the absence of added nutrients, no or scarce biomass growth is observed and PG degradation occurs by maintenance metabolism at constant removal rate by the original population of PG degraders. With the addition of nutrient, biomass exponential growth enhances aerobic PG degradation also at low temperatures (4 ° C) that occur at the high season of snowmelt. Anaerobic PG degradation without added nutrients still proceeds at constant rate (i.e. no biomass growth) and gives rise to reduced fermentation product (propionic acid, reduced Fe and Mn, methane). The addition of nitrate does not promote biomass growth but allows full PG mineralization without reduced by-products. Further exploitation on the field is necessary to fully evaluate the effect of oxygen releasing compounds and adsorbents.

Detection of DNA damage in workers exposed to JP-8 jet fuel.

PubMed

Krieg, Edward F; Mathias, Patricia I; Toennis, Christine A; Clark, John C; Marlow, Kate L; B'hymer, Clayton; Singh, Narendra P; Gibson, Roger L; Butler, Mary Ann

2012-09-18

The genotoxicity of jet propulsion fuel 8 (JP-8) was assessed in the leukocytes of archived blood specimens from U.S. Air Force personnel using the comet assay. No differences in mean comet assay measurements were found between low, moderate, and high exposure groups before or after a 4h work shift. Before the work shift, mean tail DNA and mean tail (Olive) moment increased as the concentration of benzene measured in end-exhaled breath increased, indicating that prior environmental or work-related exposures to benzene produced DNA damage. The number of cells with highly damaged DNA decreased as the pre-shift benzene concentration in breath increased. It is not clear why the decrease is occurring. Mean tail DNA and mean tail (Olive) moment decreased as the concentrations of benzene and naphthalene measured in breath immediately after the work shift increased. These inverse relationships may reflect a slower rate of absorption or a faster rate of expiration of benzene in the lung. The number of cells with highly damaged DNA increased as the concentration of urinary (2-methoxyethoxy)acetic acid (MEAA) increased. This relationship was not seen in urinary MEAA adjusted for creatinine. MEAA is a metabolite of the deicing agent 2-(2-methoxyethoxy)ethanol contained in JP-8. MEAA or a component of JP-8 correlated with MEAA may have a toxic effect on DNA. Published by Elsevier B.V.

Detection of active corrosion in reinforced and prestressed concrete: overview of NIST TIP project

NASA Astrophysics Data System (ADS)

Gonzalez-Nunez, M. A.; Nanni, A.; Matta, F.; Ziehl, P.

2011-04-01

The US transportation infrastructure has been receiving intensive public and private attention in recent years. The Federal Highway Administration estimates that 42 percent of the nearly 600,000 bridges in the Unites States are in need of structural or functional rehabilitation1. Corrosion of reinforcement steel is the main durability issue for reinforced and prestressed concrete structures, especially in coastal areas and in regions where de-icing salts are regularly used. Acoustic Emission (AE) has proved to be a promising method for detecting corrosion in steel reinforced and prestressed concrete members. This type of non-destructive test method primarily measures the magnitude of energy released within a material when physically strained. The expansive ferrous byproducts resulting from corrosion induce pressure at the steel-concrete interface, producing longitudinal and radial microcracks that can be detected by AE sensors. In the experimental study presented herein, concrete block specimens with embedded steel reinforcing bars and strands were tested under accelerated corrosion to relate the AE activity with the onset and propagation stages of corrosion. AE data along with half cell potential measurements and galvanic current were recorded to examine the deterioration process. Finally, the steel strands and bars were removed from the specimens, cleaned and weighed. The results were compared vis-à-vis Faraday's law to correlate AE measurements with degree of corrosion in each block.

Effects of anthropogenic salinization on biological traits and community composition of stream macroinvertebrates.

PubMed

Szöcs, Eduard; Coring, Eckhard; Bäthe, Jürgen; Schäfer, Ralf B

2014-01-15

Salinization of rivers resulting from industrial discharge or road-deicing can adversely affect macroinvertebrates. Trait-based approaches are a promising tool in ecological monitoring and may perform better than taxonomy-based approaches. However only little is known how and which biological traits are affected by salinization. We investigated the effects of anthropogenic salinization on macroinvertebrate communities and biological traits in the Werra River, Germany and compared the taxonomic and trait response. We found a change in macroinvertebrate community and trait composition. Communities at saline sites were characterized by the three exotic species Gammarus tigrinus, Apocorophium lacustre and Potamopyrgus antipodarum. The frequencies of trait modalities long life cycle duration, respiration by gill, ovoviviparity, shredder and multivoltinism were statistically significantly increased at saline sites. The trait-based ordination resulted in a higher explained variance than the taxonomy-based ordination, indicating a better performance of the trait-based approach, resulting in a better discrimination between saline and non-saline sites. Our results are in general agreement with other studies from Europe, indicating a trait convergence for saline streams, being dominated by the traits ovoviviparity and multivoltinism. Three further traits (respiration by gill, life cycle duration and shredders) responded strongly to salinization, but this may primarily be attributed to the dominance of a single invasive species, G. tigrinus, at the saline sites in the Werra River. © 2013 Elsevier B.V. All rights reserved.

User Manual for the NASA Glenn Ice Accretion Code LEWICE. Version 2.2.2

NASA Technical Reports Server (NTRS)

Wright, William B.

2002-01-01

A research project is underway at NASA Glenn to produce a computer code which can accurately predict ice growth under a wide range of meteorological conditions for any aircraft surface. This report will present a description of the code inputs and outputs from version 2.2.2 of this code, which is called LEWICE. This version differs from release 2.0 due to the addition of advanced thermal analysis capabilities for de-icing and anti-icing applications using electrothermal heaters or bleed air applications. An extensive effort was also undertaken to compare the results against the database of electrothermal results which have been generated in the NASA Glenn Icing Research Tunnel (IRT) as was performed for the validation effort for version 2.0. This report will primarily describe the features of the software related to the use of the program. Appendix A of this report has been included to list some of the inner workings of the software or the physical models used. This information is also available in the form of several unpublished documents internal to NASA. This report is intended as a replacement for all previous user manuals of LEWICE. In addition to describing the changes and improvements made for this version, information from previous manuals may be duplicated so that the user will not need to consult previous manuals to use this code.

Numerical investigation on super-cooled large droplet icing of fan rotor blade in jet engine

NASA Astrophysics Data System (ADS)

Isobe, Keisuke; Suzuki, Masaya; Yamamoto, Makoto

2014-10-01

Icing (or ice accretion) is a phenomenon in which super-cooled water droplets impinge and accrete on a body. It is well known that ice accretion on blades and vanes leads to performance degradation and has caused severe accidents. Although various anti-icing and deicing systems have been developed, such accidents still occur. Therefore, it is important to clarify the phenomenon of ice accretion on an aircraft and in a jet engine. However, flight tests for ice accretion are very expensive, and in the wind tunnel it is difficult to reproduce all climate conditions where ice accretion can occur. Therefore, it is expected that computational fluid dynamics (CFD), which can estimate ice accretion in various climate conditions, will be a useful way to predict and understand the ice accretion phenomenon. On the other hand, although the icing caused by super-cooled large droplets (SLD) is very dangerous, the numerical method has not been established yet. This is why SLD icing is characterized by splash and bounce phenomena of droplets and they are very complex in nature. In the present study, we develop an ice accretion code considering the splash and bounce phenomena to predict SLD icing, and the code is applied to a fan rotor blade. The numerical results with and without the SLD icing model are compared. Through this study, the influence of the SLD icing model is numerically clarified.

Water quality of selected rivers in the New England Coastal Basins in Maine, Massachusetts, New Hampshire, and Rhode Island, 1998-2000

USGS Publications Warehouse

Campo, Kimberly W.; Flanagan, Sarah M.; Robinson, Keith W.

2003-01-01

Nine rivers were monitored routinely for a variety of field conditions, dissolved ions, and nutrients during 1998-2000 as part of the New England Coastal Basins (NECB) study of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program. The nine rivers, located primarily in the Boston metropolitan area, represented a gradient of increasing urbanization from 1 to 68 percent urban land use. Additional water samples were collected and analyzed for pesticides and volatile organic compounds at two of the nine rivers. Specific conductance data from all rivers were correlated with urban land use; specific conductance values increased during winter at some sites indicating the effect of road de-icing applications. In the more intensely urbanized basins, concentrations of sodium and chloride were high during winter and likely are attributed to road de-icing applications. Concentrations of total nitrogen and the various inorganic and organic nitrogen species were correlated with the percentage of urban land in the drainage basin. Total phosphorus concentrations also were correlated with urbanization in the drainage basin, but only for rivers draining less than 50 square miles. Preliminary U.S. Environmental Protection Agency total nitrogen and total phosphorus criteria for the rivers in the area were frequently exceeded at many of the rivers sampled. At the two sites monitored for pesticides and volatile organic compounds, the Aberjona and Charles Rivers near Boston, greater detection frequencies of pesticides were in samples from the spring and summer when pesticide usage was greatest. At both sites, herbicides were detected more commonly than insecticides. The herbicides prometon and atrazine and the insecticide diazinon were detected in over 50 percent of all samples collected from both rivers. No water samples contained pesticide concentrations exceeding any U.S. Environmental Protection Agency drinking-water standard or criteria for protecting freshwater aquatic life. The volatile organic compounds trichloroethylene, tetrachloroethylene, and cis-1,2- dichloroethylene--all solvents and de-greasers--were detected in all water samples from both rivers. The gasoline oxygenate methyl tert-butyl ether (MTBE) and the disinfection by-product chloroform were detected in all but one water sample from the two rivers. Two water samples from the Charles River had trichloroethylene concentrations that exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level of 5 micrograms per liter for drinking water. Selected water-quality data from two NCEB rivers in the Boston metropolitan area were compared to two similarly sized intensely urban rivers in another NAWQA study area in the New York City metropolitan area and to other urban rivers sampled as part of the NAWQA Program nationally. Nutrient total nitrogen and total phosphorus concentrations and yields were less in the NECB study area than in the other study areas. In addition, the pesticides atrazine, carbaryl, diazinon, and prometon were detected less frequently and at lower concentrations in the two NECB rivers than in the New York City area streams or in the other urban NAWQA streams. Concentrations of the insecticides diazinon and carbaryl were detected more frequently and at higher concentrations in the NECB study area than in the other urban rivers sampled by NAWQA nationally. Detection frequency and concentrations of volatile organic compounds generally were higher in the two NECB streams than in the New York City area streams or in other urban NAWQA streams.

Development of an Organosilicon-Based Superhydrophobic/Icephobic Surface Using an Atmospheric Pressure Plasma Jet =

NASA Astrophysics Data System (ADS)

Asadollahi, Siavash

During the past few decades, plasma-based surface treatment methods have gained a lot of interest in various applications such as thin film deposition, surface etching, surface activation and/or cleaning, etc. Generally, in plasma-based surface treatment methods, high-energy plasma-generated species are utilized to modify the surface structure or the chemical composition of a substrate. Unique physical and chemical characteristics of the plasma along with the high controllability of the process makes plasma treatment approaches very attractive in several industries. Plasma-based treatment methods are currently being used or investigated for a number of practical applications, such as adhesion promotion in auto industry, wound management and cancer treatment in biomedical industry, and coating development in aerospace industry. In this study, a two-step procedure is proposed for the development of superhydrophobic/icephobic coatings based on atmospheric-pressure plasma treatment of aluminum substrates using air and nitrogen plasma. The effects of plasma parameters on various surface properties are studied in order to identify the optimum conditions for maximum coating efficiency against icing and wetting. In the first step, the interactions between air or nitrogen plasma and the aluminum surface are studied. It is shown that by reducing jet-to-substrate distance, air plasma treatment, unlike nitrogen plasma treatment, is capable of creating micro-porous micro-roughened structures on the surface, some of which bear a significant resemblance to the features observed in laser ablation of metals with short and ultra-short laser pulses. The formation of such structures in plasma treatment is attributed to a transportation of energy from the jet to the surface over a very short period of time, in the range of picoseconds to microseconds. This energy transfer is shown to occur through a streamer discharge from the rotating arc source in the jet body to a close proximity of the surface, and then through multiple seemingly random electric arcs on the surface. The formation of these discharges is facilitated by the near-infinite conductivity of the air plasma column. The micro-porous micro-roughened structure developed in this step is then used as the substrate for coating deposition. In the next step, first the plasma jet is slightly modified with a quartz tube surrounding the jet-head. This modification allows for ignition and maintenance of a very weak plasma while hindering the diffusion of oxygen into the plasma and thus increasing the amount of organic deposition on the surface. This is confirmed by the chemical characterization of the surfaces developed using the modified jet. Furthermore, it is shown that this modification can significantly affect surface morphology, leading to a finer surface structure with different levels of roughness. Hydrophobic materials are then deposited on the surface in the presence of HMDSO using nitrogen plasma. Several samples are prepared with different precursor flow rates, plasma generation powers and number of deposition passes. All coatings are characterized regarding their surface morphology, chemical composition, wetting behavior and icephobic characteristics. It is shown that at low precursor flow rates, coating deposition is not enough for a full coverage of the surface. On the other hand, at high flow rates coating deposition can completely cover the surface features originated from the air plasma treatment process, thus negating the effects of an important roughness level. At the median flow rate, which was identified to be 5 g/h, the coating can fully cover the surface while maintaining the pre-existing surface features. It is also shown that by increasing the number of plasma deposition passes, surface features become slightly larger while the amount of organic deposition on the surface increases. Finally, it is shown that in high plasma generation powers, the amount of oxide deposition on the surface increases, leading to lower contact angles and higher ice adhesion strengths. In order to estimate coatings' efficiency in practical applications, coating's stability against some environmental factors is studied. At first, the effects of multiple icing/deicing cycles on surface properties is investigated. SEM studies confirm the removal of the coating material from the surface in all cases after multiple icing/deicing cycles. However, it is shown that the sample resulting from the lowest generation power combined with median flow rate and 3 passes of plasma deposition can maintain its hydrophobicity and icephobicity for up to 10 cycles of icing/deicing. This sample is then exposed to an equivalent of up to 4 years of natural ultraviolet exposure and the effects of UV on surface properties were studied. It is suggested that ultraviolet exposure may be capable of reorganizing the organic functions in the coating structure, leading to shorter siloxane chains with denser methyl functionalization, thus affecting the wetting and icing behavior of the surface. Ice adhesion strength was shown to decrease significantly after the equivalent of 3 years of natural UV exposure. The procedure introduced in this thesis is a cheap, quick, and environmentally friendly method for development of superhydrophobic/icephobic coatings on aluminum substrates. Therefore, it can be easily implemented in several industrial applications where outdoor structures are expected to be exposed to severe icing events.

Performance and durability tests of smart icephobic coatings to reduce ice adhesion

NASA Astrophysics Data System (ADS)

Janjua, Zaid A.; Turnbull, Barbara; Choy, Kwang-Leong; Pandis, Christos; Liu, Junpeng; Hou, Xianghui; Choi, Kwing-So

2017-06-01

The accretion of ice can cause damage in applications ranging from power lines and shipping decks, to wind turbines and rail infrastructure. In particular on aircraft, it can change aerodynamic characteristics, greatly affecting the flight safety. Commercial aircraft are therefore required to be equipped with de-icing devices, such as heating mats over the wings. The application of icephobic coatings near the leading edge of a wing can in theory reduce the high power requirements of heating mats, which melt ice that forms there. Such coatings are effective in preventing the accretion of runback ice, formed from airborne supercooled droplets, or the water that the heating mats generate as it is sheared back over the wing's upper surface. However, the durability and the practicality of applying them over a large wing surface have been prohibitive factors in deploying this technology so far. Here, we evaluated the ice adhesion strength of four non-conductive coatings and seven thermally conductive coatings by shearing ice samples from coated plates by spinning them in a centrifuge device. The durability of the coating performance was also assessed by repeating the tests, each time regrowing ice samples on the previously-used coatings. Contact angle parameters of each coating were tested for each test to determine influence on ice adhesion strength. The results indicate that contact angle hysteresis is a crucial parameter in determining icephobicity of a coating and hydrophobicity is not necessarily linked to icephobicity.

Aircraft Fleet on the Tarmac at the Lewis Flight Propulsion Laboratory

NASA Image and Video Library

1946-04-21

This fleet of military aircraft was used in the 1940s for research at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory in Cleveland, Ohio. The NACA Lewis flight research program was established in March 1943 to augment the lab’s wartime research efforts. NACA Lewis possessed a host of wind tunnels, test stands, and other ground facilities designed to replicate flight conditions, but actual flight tests remained an integral research tool. The military loaned NACA Lewis 15 different aircraft during World War II and six others in the six months following the end of hostilities. During the war these aircraft supported three main efforts: the improved performance of reciprocating engines, better fuel additives and mixtures, and deicing systems. The wartime researchers used the types of aircraft which the studies were intended to improve. After the war the research aircraft served as test beds to investigate engines or systems that often had little to do with the research aircraft. During the war, NACA Lewis’ three pilots were supported by 16 flight engineers, 36 mechanics, and 10 instrumentation specialists. The visible aircraft, from left to right, are a Boeing B-29 Superfortress, a Martin B-26A Marauder, two Consolidated B-24 Liberators, a Cessna UC-78 Bobcat, and a Northrop P-61 Black Widow. Partially obscured are a North American P-51 Mustang, a Bell P-63 King Cobra, a North American AT-6 Texan, and a Lockheed RA-29 Hudson.

Surface disposal of produced waters in western and southwestern Pennsylvania: potential for accumulation of alkali-earth elements in sediments

USGS Publications Warehouse

Skalak, Katherine J.; Engle, Mark A.; Rowan, Elisabeth L.; Jolly, Glenn D.; Conko, Kathryn M.; Benthem, Adam J.; Kraemer, Thomas F.

2014-01-01

Waters co-produced with hydrocarbons in the Appalachian Basin are of notably poor quality (concentrations of total dissolved solids (TDS) and total radium up to and exceeding 300,000 mg/L and 10,000 pCi/L, respectively). Since 2008, a rapid increase in Marcellus Shale gas production has led to a commensurate rise in associated wastewater while generation of produced water from conventional oil and gas activities has continued. In this study, we assess whether disposal practices from treatment of produced waters from both shale gas and conventional operations in Pennsylvania could result in the accumulation of associated alkali earth elements. The results from our 5 study sites indicate that there was no increase in concentrations of total Ra (Ra-226) and extractable Ba, Ca, Na, or Sr in fluvial sediments downstream of the discharge outfalls (p > 0.05) of publicly owned treatment works (POTWs) and centralized waste treatment facilities (CWTs). However, the use of road spreading of brines from conventional oil and gas wells for deicing resulted in accumulation of Ra-226 (1.2 ×), and extractable Sr (3.0 ×), Ca (5.3 ×), and Na (6.2 ×) in soil and sediment proximal to roads (p < 0.05). Although this study is an important initial assessment of the impacts of these disposal practices, more work is needed to consider the environmental consequences of produced waters management.

The Influence of Corrosion and Cross-Section Diameter on the Mechanical Properties of B500c Steel

NASA Astrophysics Data System (ADS)

Apostolopoulos, Ch. Alk.

2009-03-01

Corrosion is a negative contributor on the structural integrity of concrete structures and leads to degradation of the mechanical properties of steel rebar. Exposure to chloride, seawater, salt and saltwater and deicing chemical environments influences the concrete-steel bond and weakens it. A considerable strength factor of the two-phase steel B500c (martensitic, ferritic-perlitic) is considered to be the outer martensitic cortex thickness, which varies according to the area of the rebar cross section. In order to evaluate the influence of corrosion and the size of the area on the mechanical properties of B500c steel, an experimental investigation was conducted on B500c ribbed steel rebar of 8, 12, 16, and 18 mm diameter, and which were artificially corroded for 10, 20, 30, 45, 60, 90, and 120 days. The laboratory tests suggest that corrosion duration and rebar cross-sectional area size had a significant impact on the strength and ductility degradation of the specimens. The tensile mechanical properties before and after corrosion indicated progressive variation and drastic drop in their values. The extended salt spray exposure enhanced the damage and created pits and notches, resulting in stress concentration points and progressive reduction of ductility and available energy. Anti-seismic design and codes that ignore the influence of the size of the cross-section area and the level of corrosion and mechanical behavior of reinforcing steel could lead to unpredictable performance during severe ground motion.

Source-Water Protection and Water-Quality Investigations in the Cambridge, Massachusetts, Drinking-Water Supply System

USGS Publications Warehouse

Waldron, Marcus C.; Norton, Chip; MacDonald, Timothy W.D.

1998-01-01

Introduction The Cambridge Water Department (CWD) supplies about 15 million gallons of water each day to more than 95,000 customers in the City of Cambridge, Massachusetts. Most of this water is obtained from a system of reservoirs located in Cambridge and in parts of five other suburban-Boston communities. The drainage basin that contributes water to these reservoirs includes several potential sources of drinking-water contaminants, including major highways, secondary roads, areas of commercial and industrial development, and suburban residential tracts. The CWD is implementing a comprehensive Source-Water Protection Plan to ensure that the highest quality water is delivered to the treatment plant. A key element of this plan is a program that combines systematic monitoring of the drainage basin with detailed investigations of the effects of nonpoint-source contaminants, such as highway-deicing chemicals, nutrients, oxygen-demanding organic compounds, bacteria, and trace metals arising from stormwater runoff. The U.S. Geological Survey (USGS) is working with the CWD and the Massachusetts Highway Department (MassHighway) to develop a better understanding of the sources, transport, and fate of many of these contaminants. This Fact Sheet describes source-water protection and water-quality investigations currently underway in the Cambridge drinking-water supply system. The investigations are designed to complement a national effort by the USGS to provide water suppliers and regulatory agencies with information on the vulnerability of water supplies and the movement and fate of source-water contaminants.

Specially-Equipped Martin XB-25E Icing Research Aircraft

NASA Image and Video Library

1947-08-21

In 1946 the Lewis Flight Propulsion Laboratory became the NACA’s official icing research center. In addition to the Icing Research Tunnel, the lab possessed several aircraft modified for icing work, including a Consolidated B-24M Liberator and a North American XB-25E Mitchell, seen here. The XB-25E’s frequent engine fires allegedly resulted in its “Flamin’ Maimie” nickname. The aircraft’s nose art, visible in this photograph, includes a leather-jacketed mechanic with an extinguisher fleeing a fiery woman. North American developed the B-25 in the mid-1930s as a transport aircraft, but it was hurriedly reconfigured as a medium bomber for World War II. This XB-25E was a single prototype designed in 1942 specifically to test an exhaust gas ice prevention system developed by NACA researcher Lewis Rodert. The system circulated the engines’ hot bleed air to the wings, windshield, and tail. The XB-25E was utilized at the NACA’s Ames Aeronautical Laboratory for two years before being transferred to Cleveland in July 1944. NACA Lewis mechanics modified the aircraft further by installing electrical heating in the front fuselage, propellers, inboard sing, cowls, and antennae. Lewis pilots flew the B-24M and XB-25E into perilous weather conditions all across the country to study both deicing technologies and the physics of ice-producing clouds. These dangerous flights led to advances in weather sensing instruments and flight planning.

Nanotechnologies for efficient solar and wind energy harvesting and storage

NASA Astrophysics Data System (ADS)

Eldada, Louay A.

2010-08-01

We describe nanotechnologies used to improve the efficient harvest of energy from the Sun and the wind, and the efficient storage of energy in secondary batteries and ultracapacitors, for use in a variety of applications including smart grids, electric vehicles, and portable electronics. We demonstrate high-quality nanostructured copper indium gallium selenide (CIGS) thin films for photovoltaic (PV) applications. The self-assembly of nanoscale p-n junction networks creates n-type networks that act as preferential electron pathways, and p-type networks that act as preferential hole pathways, allowing positive and negative charges to travel to the contacts in physically separated paths, reducing charge recombination. We also describe PV nanotechnologies used to enhance light trapping, photon absorption, charge generation, charge transport, and current collection. Furthermore, we describe nanotechnologies used to improve the efficiency of power-generating wind turbines. These technologies include nanoparticle-containing lubricants that reduce the friction generated from the rotation of the turbines, nanocoatings for de-icing and self-cleaning technologies, and advanced nanocomposites that provide lighter and stronger wind blades. Finally, we describe nanotechnologies used in advanced secondary batteries and ultracapacitors. Nanostructured powder-based and carbon-nanotube-based cathodes and anodes with ultra-high surface areas boost the energy and power densities in secondary batteries, including lithium-ion and sodium-sulfur batteries. Nanostructured carbon materials are also controlled on a molecular level to offer large surface areas for the electrodes of ultracapacitors, allowing to store and supply large bursts of energy needed in some applications.

Investigation of selected potential environmental contaminants: ethylene glycol, propylene glycols and butylene glycols. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, L.M.

1979-05-01

This report reviews aspects of production, use, environmental exposure and biological effects of ethylene glycol, two isomers of propylene glycol (1,2- and 1,3-propanediol) and four isomers of butylene glycol (1,3-, 1,4-, 2,3-, and 1,2- butanediol). Annual production of ethylene glycol is about 3.7 billion pounds for use primarily in antifreeze and polyester fiber. About 0.5 billion pounds of 1,2-propanediol are produced per year for use in polyester resins, food, pharmaceuticals, and cellophane. Annual domestic demand for 1,4-butanediol is about 0.2 billion pounds for use in the production of tetra-hydrofuran and acetylenic chemicals. The other title glycols are of less importancemore » commercially. The major source of environmental contamination by ethylene glycol and 1,2-propanediol is likely from the disposal of spent antifreeze and de-icing fluids. However, limited monitoring data make it difficult to adequately assess environmental exposure to the glycols. The glycols are capable of being degraded by a variety of acclimated and unacclimated soil, water, and sewage microorganisms. In humans, ethylene glycol intoxication, usually as a result of accidental ingestion of antifreeze, may result in nausea, hypertension, tachycardia, cardiopulmonary failure, renal impairment, coma and death. 1,2-Propanediol is a GRAS food additive of low toxicity. 1,3-Butanediol has been studied as a source of dietary energy. Few studies are available on 1,2-, 2,3- and 1,4-butanediol or on 1,3-propanediol.« less

Field site leaching from recycled concrete aggregates applied as sub-base material in road construction.

PubMed

Engelsen, Christian J; Wibetoe, Grethe; van der Sloot, Hans A; Lund, Walter; Petkovic, Gordana

2012-06-15

The release of major and trace elements from recycled concrete aggregates used in an asphalt covered road sub-base has been monitored for more than 4 years. A similar test field without an asphalt cover, directly exposed to air and rain, and an asphalt covered reference field with natural aggregates in the sub-base were also included in the study. It was found that the pH of the infiltration water from the road sub-base with asphalt covered concrete aggregates decreased from 12.6 to below pH 10 after 2.5 years of exposure, whereas this pH was reached within only one year for the uncovered field. Vertical temperature profiles established for the sub-base, could explain the measured infiltration during parts of the winter season. When the release of major and trace elements as function of field pH was compared with pH dependent release data measured in the laboratory, some similar pH trends were found. The field concentrations of Cd, Ni, Pb and Zn were found to be low throughout the monitoring period. During two of the winter seasons, a concentration increase of Cr and Mo was observed, possibly due to the use of de-icing salt. The concentrations of the trace constituents did not exceed Norwegian acceptance criteria for ground water and surface water Class II. Copyright © 2012 Elsevier B.V. All rights reserved.

Study on bouncing motion of a water drop collision on superhydrophobic surface under icing conditions

NASA Astrophysics Data System (ADS)

Maeda, Tetsuro; Morita, Katsuaki; Kimura, Shigeo

2017-11-01

When micro droplets in the air are supercooled and collide with the object, they froze on the surface at the time of a collision and can be defined as icing. If supercooled water droplets collide with an airfoil of an aircraft in flight and shape changes, there is a danger of losing lift and falling. Recently, the ice protection system using a heater and Anti- / Deicing (superhydrophobic) coating is focused. In this system, colliding water droplets are melted by the heat of the heater at the tip of the blade, and the water droplet is bounced by the aerodynamic force on the rear superhydrophobic coating. Thus, it prevents the phenomenon of icing again at the back of the wing (runback ice). Therefore, it is possible to suppress power consumption of the electric heater. In that system, it is important to withdraw water droplets at an extremely superhydrophobic surface at an early stage. However, research on bouncing phenomenon on superhydrophobic surface under icing conditions are not done much now. Therefore, in our research, we focus on one drop supercooled water droplet that collides with the superhydrophobic surface in the icing phenomenon, and aim to follow that phenomenon. In this report, the contact time is defined as the time from collision of a water droplet to bouncing from the superhydrophobic surface, and various parameters (temperature, speed, and diameter) on water droplets under icing conditions are set as the water drop bouncing time (contact time) of the product.

Mild and General Access to Diverse 1H-Benzotriazoles via Diboron-Mediated N-OH Deoxygenation and Palladium-Catalyzed C-C and C-N Bond Formation.

PubMed

Gurram, Venkateshwarlu; Akula, Hari K; Garlapati, Ramesh; Pottabathini, Narender; Lakshman, Mahesh K

2015-02-09

Benzotriazoles are a highly important class of compounds with broad-ranging applications in such diverse areas as medicinal chemistry, as auxiliaries in organic synthesis, in metallurgical applications, in aircraft deicing and brake fluids, and as antifog agents in photography. Although there are numerous approaches to N-substituted benzotriazoles, the essentially one general method to N-unsubstituted benzotriazoles is via diazotization of o -phenylenediamines, which can be limited by the availability of suitable precursors. Other methods to N-unsubstitued benzotriazoles are quite specialized. Although reduction of 1-hydroxy-1 H -benzotriazoles is known the reactions are not particularly convenient or broadly applicable. This presents a limitation for easy access to and availability of diverse benzotriazoles. Herein, we demonstrate a new, broadly applicable method to diverse 1 H -benzotriazoles via a mild diboron-reagent mediated deoxygenation of 1-hydroxy-1 H -benzotriazoles. We have also evaluated sequential deoxygenation and Pd-mediated C-C and C-N bond formation as a one-pot process for further diversification of the benzotriazole moiety. However, results indicated that purification of the deoxygenation product prior to the Pd-mediated reaction is critical to the success of such reactions. The overall chemistry allows for facile access to a variety of new benzotriazoles. Along with the several examples presented, a discussion of the advantages of the approaches is described, as also a possible mechanism for the deoxygenation process.

Mild and General Access to Diverse 1H-Benzotriazoles via Diboron-Mediated N–OH Deoxygenation and Palladium-Catalyzed C–C and C–N Bond Formation

PubMed Central

Gurram, Venkateshwarlu; Akula, Hari K.; Garlapati, Ramesh; Pottabathini, Narender; Lakshman, Mahesh K.

2015-01-01

Benzotriazoles are a highly important class of compounds with broad-ranging applications in such diverse areas as medicinal chemistry, as auxiliaries in organic synthesis, in metallurgical applications, in aircraft deicing and brake fluids, and as antifog agents in photography. Although there are numerous approaches to N-substituted benzotriazoles, the essentially one general method to N-unsubstituted benzotriazoles is via diazotization of o-phenylenediamines, which can be limited by the availability of suitable precursors. Other methods to N-unsubstitued benzotriazoles are quite specialized. Although reduction of 1-hydroxy-1H-benzotriazoles is known the reactions are not particularly convenient or broadly applicable. This presents a limitation for easy access to and availability of diverse benzotriazoles. Herein, we demonstrate a new, broadly applicable method to diverse 1H-benzotriazoles via a mild diboron-reagent mediated deoxygenation of 1-hydroxy-1H-benzotriazoles. We have also evaluated sequential deoxygenation and Pd-mediated C–C and C–N bond formation as a one-pot process for further diversification of the benzotriazole moiety. However, results indicated that purification of the deoxygenation product prior to the Pd-mediated reaction is critical to the success of such reactions. The overall chemistry allows for facile access to a variety of new benzotriazoles. Along with the several examples presented, a discussion of the advantages of the approaches is described, as also a possible mechanism for the deoxygenation process. PMID:25729343

User's Manual for LEWICE Version 3.2

NASA Technical Reports Server (NTRS)

Wright, William

2008-01-01

A research project is underway at NASA Glenn to produce a computer code which can accurately predict ice growth under a wide range of meteorological conditions for any aircraft surface. This report will present a description of the code inputs and outputs from version 3.2 of this software, which is called LEWICE. This version differs from release 2.0 due to the addition of advanced thermal analysis capabilities for de-icing and anti-icing applications using electrothermal heaters or bleed air applications, the addition of automated Navier-Stokes analysis, an empirical model for supercooled large droplets (SLD) and a pneumatic boot option. An extensive effort was also undertaken to compare the results against the database of electrothermal results which have been generated in the NASA Glenn Icing Research Tunnel (IRT) as was performed for the validation effort for version 2.0. This report will primarily describe the features of the software related to the use of the program. Appendix A has been included to list some of the inner workings of the software or the physical models used. This information is also available in the form of several unpublished documents internal to NASA. This report is intended as a replacement for all previous user manuals of LEWICE. In addition to describing the changes and improvements made for this version, information from previous manuals may be duplicated so that the user will not need to consult previous manuals to use this software.

Experimental analysis of electrical properties of composite materials

NASA Astrophysics Data System (ADS)

Fiala, L.; Rovnaník, P.; Černý, R.

2017-02-01

Dry cement-based composites are electrically non-conductive materials that behave in electric field like dielectrics. However, a relatively low amount of electrically conductive admixture significantly increases the electrical conductivity which extends applicability of such materials in practice. Therefore, they can be used as self-monitoring sensors controlling development of cracks; as sensors monitoring moisture content or when treated by an external electrical voltage as heat sources used for deicing of material's surface layer. Alkali-activated aluminosilicates (AAA), as competing materials to cement-based materials, are intensively investigated in the present due to their superior durability and environmental impact. Whereas the electrical properties of AAA are similar to those cement-based, they can be enhanced in the same way. In both cases, it is crucial to find a reasonable amount of electrically conductive phase to design composites with a sufficient electrical conductivity at an affordable price. In this paper, electrical properties of composites based on AAA binder and electrically conductive admixture represented by carbon nanotubes (CNT) are investigated. Measurements of electrical properties are carried out by means of 2-probes DC technique on nine types of samples; reference sample without the conductive phase and samples with CNT admixture in amount of 0.1 % - 2.5 % by vol. A significant increase of the electrical conductivity starts from the amount of 0.5 % CNT admixture and in case of 2.5 % CNT is about three orders of magnitude higher compared to the reference sample.

Conceptual design studies of the 5 m terahertz antenna for Dome A, Antarctica

NASA Astrophysics Data System (ADS)

Yang, Ji; Zuo, Ying-Xi; Lou, Zheng; Cheng, Jing-Quan; Zhang, Qi-Zhou; Shi, Sheng-Cai; Huang, Jia-Sheng; Yao, Qi-Jun; Wang, Zhong

2013-12-01

As the highest, coldest and driest place in Antarctica, Dome A provides exceptionally good observing conditions for ground-based observations over terahertz wavebands. The 5 m Dome A Terahertz Explorer (DATE5) has been proposed to explore new terahertz windows, primarily over wavelengths between 350 and 200 μm. DATE5 will be an open-air, fully-steerable telescope that can function by unmanned operation with remote control. The telescope will be able to endure the harsh polar environment, including high altitude, very low temperature and very low air pressure. The unique specifications, including high accuracies for surface shape and pointing and fully automatic year-around remote operation, along with a stringent limit on the periods of on-site assembly, testing and maintenance, bring a number of challenges to the design, construction, assembly and operation of this telescope. This paper introduces general concepts related to the design of the DATE5 antenna. Beginning from an overview of the environmental and operational limitations, the design specifications and requirements of the DATE5 antenna are listed. From these, major aspects on the conceptual design studies, including the antenna optics, the backup structure, the panels, the subreflector, the mounting and the antenna base structure, are explained. Some critical issues of performance are justified through analyses that use computational fluid dynamics, thermal analysis and de-icing studies, and the proposed approaches for test operation and on-site assembly. Based on these studies, we conclude that the specifications of the DATE5 antenna can generally be met by using enhanced technological approaches.

A clamp fixture with interdigital capacitive sensor for in situ evaluation of wire insulation

NASA Astrophysics Data System (ADS)

Sheldon, Robert T.; Bowler, Nicola

2014-02-01

An interdigital capacitive sensor has been designed and optimized for testing aircraft wires by applying a quasinumerical model developed and reported previously. The sensor consists of two patches of interdigitated electrodes, connected by a long signal bus strip, that are intended to conform to two sides of an insulated wire. The electrodes are deposited using photolithography upon a 25.4-μm-thick Kapton® polyimide film. The two electrode patches are attached to the two jaws of a plastic spring-loaded clamp, with each jaw having a milled groove designed such that the electrodes conform to the curved surface of the insulated wire. An SMA connector and cable connect between the electrodes on the clamp and an LCR meter. Segments of pristine M5086/2 aircraft wire, each 10 cm long, were immersed in fluids commonly found in aircraft environments, to cause accelerated chemical degradation. The effects of Jet A fuel, deicing fluid, hydraulic fluid, aircraft cleaner, isopropyl alcohol and distilled water were studied. The frequency-dependent capacitance and dissipation factor of one pristine wire segment and of those degraded in the six fluid environments were measured within the frequency range 100 Hz to 1 MHz. Significant changes in capacitance and dissipation factor were observed for all degraded wires, compared with results for the pristine sample, suggesting the feasibility of detecting insulation degradation in the field. The results were also consistent with those of a similar experiment performed on sheets of Nylon 6, the material that comprises the outermost layer of M5086/2 wire.

Chemical quality of ground water on Cape Cod, Massachusetts

USGS Publications Warehouse

Frimpter, M.H.; Gay, F.B.

1979-01-01

Cape Cod is a 440 square mile hook-shaped peninsula which extends 40 miles into the Atlantic. Freshwater in Pleistocene sand and gravel deposits is the source of supply for nearly 100 municipal and thousands of private domestic wells. Most ground water on Cape Cod is of good chemical quality for drinking and other uses. It is characteristically low in dissolved solids and is soft. In 90 percent of the samples analyzed, dissolved solids were less than 100 mg/l (milligrams per liter) and pH was less than 7.0. Highway deicing salt, sea-water flooding due to storms , and saltwater intrusion due to ground-water withdrawal are sources of sodium chloride contamination. Chloride concentrations have increased from 20 to 140 mg/l, owing to saltwater intrusion at Provincetown 's wells in Truro. In Yarmouth, contaminated ground water near a salt-storage area contained as much as 1,800 mg/l chloride. Heavy metals, insecticides, and herbicides were not found at concentrations above the U.S. Environmental Protection Agency 's recommended limits for public drinking-water supplies, but iron and manganese in some samples exceeded those limits. Ninety percent of 84 samples analyzed for nitrate reported as nitrogen contained less than 1.3 mg/l and 80 percent contained 0.5 mg/l or less of nitrate as nitrogen. Water containing nitrogen in excess of 0.5 mg/l has probably been affected by municipal or domestic sewage or fertilizer, and water with less than this amount may have been affected by them. (Woodard-USGS)

Effects of road salt on larval amphibian susceptibility to parasitism through behavior and immunocompetence.

PubMed

Milotic, Dino; Milotic, Marin; Koprivnikar, Janet

2017-08-01

Large quantities of road salts are used for de-icing in temperate climates but often leach into aquatic ecosystems where they can cause harm to inhabitants, including reduced growth and survival. However, the implications of road salt exposure for aquatic animal susceptibility to pathogens and parasites have not yet been examined even though infectious diseases can significantly contribute to wildlife population declines. Through a field survey, we found a range of NaCl concentrations (50-560mg/L) in ponds known to contain larval amphibians, with lower levels found in sites close to gravel- rather than hard-surfaced roads. We then investigated how chronic exposure to environmentally-realistic levels of road salt (up to 1140mg/L) affected susceptibility to infection by trematode parasites (helminths) in larval stages of two amphibian species (Lithobates sylvaticus - wood frogs, and L. pipiens - northern leopard frogs) by considering effects on host anti-parasite behavior and white blood cell profiles. Wood frogs exposed to road salt had higher parasite loads, and also exhibited reduced anti-parasite behavior in these conditions. In contrast, infection intensity in northern leopard frogs had a non-monotonic response to road salts even though lymphocytes were only elevated at the highest concentration. Our results indicate the potential for chronic road salt exposure to affect larval amphibian susceptibility to pathogenic parasites through alterations of behavior and immunocompetence, with further studies needed at higher concentrations, as well as that of road salts on free-living parasite infectious stages. Copyright © 2017 Elsevier B.V. All rights reserved.

Single and multiple stressor effect of road deicers and Cu on Atlantic salmon (Salmo salar) alevins from hatching till swim-up.

PubMed

Mahrosh, Urma; Rosseland, Bjørn Olav; Salbu, Brit; Teien, Hans-Christian

2018-04-01

Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and dust may negatively influence organisms in downstream receiving water bodies. The present work focuses on the impact of road salt (NaCl) and Cu, separately and in mixtures on Atlantic salmon alevins from hatching till swim-up. The results showed that high road salt concentrations could induce a series of negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality. For alevins exposed to all tested road salt concentrations (100-1000mg/L), mortality was significantly higher compared to control. In exposure to Cu solutions (5-20μgCu/L), no effects on growth, morphology, swim-up or mortality of alevins compared to control were observed. In mixture solutions (road salt and Cu), ultrafiltration of the exposure water demonstrated that only 20%-40% of Cu was present as positively charged low molecular mass (LMM) Cu species assumed to be bioavailable. When exposed to road salt and Cu mixtures, negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality were observed. The overall results indicated that the road salt application could seriously affect sensitive life stages of Atlantic salmon, and application of road salt should be avoided during the late winter-early spring period. Copyright © 2017. Published by Elsevier B.V.

Performance of rice husk ash produced using a new technology as a mineral admixture in concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nehdi, M.; Duquette, J.; El Damatty, A

2003-08-01

This article investigates the use of a new technique for the controlled combustion of Egyptian rice husk to mitigate the environmental concerns associated with its uncontrolled burning and provide a supplementary cementing material for the local construction industry. The reactor used provides efficient combustion of rice husk in a short residency time via the suspension of processed particles by jets of a process air stream that is forced though stationary angled blades at high velocity. Investigations on the rice husk ash (RHA) thus produced included oxide analysis, X-ray diffraction, carbon content, grindability, water demand, pozzolanic activity index, surface area, andmore » particle size distribution measurements. In addition, concrete mixtures incorporating various proportions of silica fume (SF) and Egyptian RHA (EG-RHA) produced at different combustion temperatures were made and compared. The workability, superplasticizer and air-entraining admixture requirements, and compressive strength at various ages of these concrete mixtures were evaluated, and their resistance to rapid chloride penetrability and deicing salt surface scaling were examined. Test results indicate that contrary to RHA produced using existing technology, the superplasticizer and air-entraining agent requirements did not increase drastically when the RHA developed in this study was used. Compressive strengths achieved by concrete mixtures incorporating the new RHA exceeded those of concretes containing similar proportions of SF. The resistance to surface scaling of RHA concrete was better than that of concrete containing similar proportions of SF. While the chloride penetrability was substantially decreased by RHA, it remained slightly higher than that achieved by SF concrete.« less

Polar pollutants in municipal wastewater and the water cycle: occurrence and removal of benzotriazoles.

PubMed

Reemtsma, Thorsten; Miehe, Ulf; Duennbier, Uwe; Jekel, Martin

2010-01-01

1H-benzo-1,2,3-triazole (BTri) and its methylated analogues (tolyltriazole, TTri) are corrosion inhibitors used in many industrial applications, but also in households in dishwashing agents and in deicing fluids at airports and elsewhere. BTri and one of the TTri-isomers (4-TTri) are typical examples of polar and poorly degradable trace pollutants. Benzotriazole elimination in four wastewater treatment plants (WWTP) in Berlin ranged from 20 to 70% for 5-TTRi over 30 to 55% for BTri to insignificant for 4-TTri. WWTP effluent concentrations were in the range of 7-18 microg/L of BTri, 1-5 microg/L of 4-TTri and 0.8-1.2 microg/L of 5-TTri. BTri and 4-TTri proved to be omnipresent in surface waters of the rivers Rhine and Elbe with concentrations increasing from <0.05 microg/L to around 0.5 microg/L of BTri and 0.2-0.5 microg/L of 4-TTri over 600-700 km. Bank filtration is an important process to generate raw water for drinking water production from surface waters. Even after residence times of several months BTri and 4-TTri were determined in concentrations of a few hundred ng/L in bank filtration water. Isotherm data from batch experiments indicate that activated carbon filtration should be suitable to avoid intrusion of TTri into drinking water in partially closed water cycles. For BTri, however, sorption to activated carbon appears to be too weak and ozonation may be mandatory to remove it from raw waters. (c) 2009 Elsevier Ltd. All rights reserved.

Liquid-infused nanostructured surfaces with extreme anti-ice and anti-frost performance.

PubMed

Kim, Philseok; Wong, Tak-Sing; Alvarenga, Jack; Kreder, Michael J; Adorno-Martinez, Wilmer E; Aizenberg, Joanna

2012-08-28

Ice-repellent coatings can have significant impact on global energy savings and improving safety in many infrastructures, transportation, and cooling systems. Recent efforts for developing ice-phobic surfaces have been mostly devoted to utilizing lotus-leaf-inspired superhydrophobic surfaces, yet these surfaces fail in high-humidity conditions due to water condensation and frost formation and even lead to increased ice adhesion due to a large surface area. We report a radically different type of ice-repellent material based on slippery, liquid-infused porous surfaces (SLIPS), where a stable, ultrasmooth, low-hysteresis lubricant overlayer is maintained by infusing a water-immiscible liquid into a nanostructured surface chemically functionalized to have a high affinity to the infiltrated liquid and lock it in place. We develop a direct fabrication method of SLIPS on industrially relevant metals, particularly aluminum, one of the most widely used lightweight structural materials. We demonstrate that SLIPS-coated Al surfaces not only suppress ice/frost accretion by effectively removing condensed moisture but also exhibit at least an order of magnitude lower ice adhesion than state-of-the-art materials. On the basis of a theoretical analysis followed by extensive icing/deicing experiments, we discuss special advantages of SLIPS as ice-repellent surfaces: highly reduced sliding droplet sizes resulting from the extremely low contact angle hysteresis. We show that our surfaces remain essentially frost-free in which any conventional materials accumulate ice. These results indicate that SLIPS is a promising candidate for developing robust anti-icing materials for broad applications, such as refrigeration, aviation, roofs, wires, outdoor signs, railings, and wind turbines.

Consolidated B-24M Liberator Equipped for Icing Research

NASA Image and Video Library

1946-07-21

A Consolidated B-25M Liberator modified for icing research by the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. NACA Lewis performed a limited amount of icing research during World War II, but the program expanded significantly in 1946. The accumulation of ice on aircraft was a continual problem. The ice formations could result in extra weight, aerodynamic penalties, and blockage engine inlets. Although the Lewis icing researchers utilized numerous aircraft, the program’s two workhorses were the B-24M Liberator, seen here, and a North American XB-25E Mitchell. The Consolidated Aircraft Company created the four-engine bomber in the early 1940s. During World War II the bomber was employed on long-duration bombing missions in both Europe and the Pacific. Production of the B-24M version did not begin until October 1944 with the end of the war in Europe approaching. This resulted in scores of unneeded bombers when hostilities ended. This B-24M arrived at the NACA Lewis laboratory in November 1945. At Lewis the B-24M was repeatedly modified to study ice accretion on aircraft components. Researchers analyzed different anti-icing and deicing strategies and gathered statistical ice measurement data. The B-24M was also used to study ice buildup on jet engines. A General Electric I-16 engine was installed in the aircraft’s waist compartment with an air scoop on the top of the aircraft to duct air to the engine. Water spray nozzles inside the aircraft were employed to simulate icing conditions at the turbojet’s inlet.

Soil slurry reactors for the assessment of contaminant biodegradation

NASA Astrophysics Data System (ADS)

Toscano, G.; Colarieti, M. L.; Greco, G.

2012-04-01

Slurry reactors are frequently used in the assessment of feasibility of biodegradation in natural soil systems. The rate of contaminant removal is usually quantified by zero- or first-order kinetics decay constants. The significance of such constants for the evaluation of removal rate in the field could be questioned because the slurry reactor is a water-saturated, well-stirred system without resemblance with an unsaturated fixed bed of soil. Nevertheless, a kinetic study with soil slurry reactors can still be useful by means of only slightly more sophisticated kinetic models than zero-/first-order decay. The use of kinetic models taking into account the role of degrading biomass, even in the absence of reliable experimental methods for its quantification, provides further insight into the effect of nutrient additions. A real acceleration of biodegradation processes is obtained only when the degrading biomass is in the growth condition. The apparent change in contaminant removal course can be useful to diagnose biomass growth without direct biomass measurement. Even though molecular biology techniques are effective to assess the presence of potentially degrading microorganism in a "viable-but-nonculturable" state, the attainment of conditions for growth is still important to the development of enhanced remediation techniques. The methodology is illustrated with reference to data gathered for two test sites, Oslo airport Gardermoen in Norway (continuous contamination by aircraft deicing fluids) and the Trecate site in Italy (aged contamination by crude oil spill). This research is part of SoilCAM project (Soil Contamination, Advanced integrated characterisation and time-lapse Monitoring 2008-2012, EU-FP7).

Water quality of stormwater generated from an airport in a cold climate, function of an infiltration pond, and sampling strategy with limited resources.

PubMed

Jia, Yu; Ehlert, Ludwig; Wahlskog, Cecilia; Lundberg, Angela; Maurice, Christian

2017-12-05

Monitoring pollutants in stormwater discharge in cold climates is challenging. An environmental survey was performed by sampling the stormwater from Luleå Airport, Northern Sweden, during the period 2010-2013, when urea was used as a main component of aircraft deicing/anti-icing fluids (ADAFs). The stormwater collected from the runway was led through an oil trap to an infiltration pond to store excess water during precipitation periods and enhance infiltration and water treatment. Due to insufficient capacity, an emergency spillway was established and equipped with a flow meter and an automatic sampler. This study proposes a program for effective monitoring of pollutant discharge with a minimum number of sampling occasions when use of automatic samplers is not possible. The results showed that 90% of nitrogen discharge occurs during late autumn before the water pipes freeze and during snow melting, regardless of the precipitation during the remaining months when the pollutant discharge was negligible. The concentrations of other constituents in the discharge were generally low compared to guideline values. The best data quality was obtained using flow controlled sampling. Intensive time-controlled sampling during late autumn (few weeks) and snow melting (2 weeks) would be sufficient for necessary information. The flow meters installed at the rectangular notch appeared to be difficult to calibrate and gave contradictory results. Overall, the spillway was dry, as water infiltrated into the pond, and stagnant water close to the edge might be registered as flow. Water level monitoring revealed that the infiltration capacity gradually decreased with time.

Urbanization Changes the Temporal Dynamics of Nutrients and Water Chemistry

NASA Astrophysics Data System (ADS)

Steele, M.; Badgley, B.

2017-12-01

Recent studies find that urban development alters the seasonal dynamics of nutrient concentrations, where the highest concentrations of nitrogen occurred during the winter in urban watersheds, rather than the summer. However, the effects of urbanization on the seasonal concentrations of other nutrients and chemical components is unknown. Therefore, to determine how urbanization changes the seasonal dynamics, once a week we measured concentrations of dissolved organic carbon (DOC), nutrients (NO3, DON, TN, PO4), base cations (Ca, Mg, Na, K), anions (F, Cl, SO4), pH, sediment, temperature, conductivity, and dissolved oxygen (DO) of nine urban, agricultural, and minimally developed watersheds in southwest Virginia, USA. We found that urbanization disrupted the seasonal dynamics of all metrics, except DON, PO4, Ca, sediment, and DO, where some shifted to high concentrations during the winter (Cl, conductivity), highs during late winter or spring (DOC, Na), a season low (TN, SO4, NO3) or high (NH4) during the summer, or remained more constant throughout the year compared to the reference watersheds (Mg, K, pH). The complex changes in seasonal dynamics coincide with a decoupling of common correlations between constituents; for example, DO and NO3 are negatively correlated in reference watersheds (NO3 increases, DO decreases), but positively correlated in urban watersheds. These results suggest that as watersheds become more intensely developed, the influence of natural drivers like temperature and vegetation become steadily overcome by the influence of urban drivers like deicing salts and wastewater leakage, which exert increasing control of seasonal water quality and aquatic habitat.

Trends in riverine element fluxes: A chronicle of regional socio-economic changes.

PubMed

Kopáček, Jiří; Hejzlar, Josef; Porcal, Petr; Posch, Maximilian

2017-11-15

We show how concentrations of water solutes in the Vltava River (Czech Republic) and their riverine outputs from the catchment were modified by socio-economic changes, land use, and hydrology between 1960 and 2015. In the early 1960s, HCO 3 and Ca were the dominant ions. During 1960-1989 (a period of planned economy with an over-use of synthetic fertilizers, excessive draining of agricultural land and little environmental protection), the riverine concentrations of strong acid anions (SAAs: SO 4 , NO 3 , and Cl) increased 2-4-fold and their leaching was accompanied for by a 1.4-1.8-fold increase in concentrations of Ca, Mg, K, and Na. SAAs mostly originated from diffuse agricultural sources (synthetic fertilizers and mineralization of organic matter in freshly drained and deeply tilled agricultural land) and their annual average concentrations (as well as those of Ca, Mg, and K) were positively correlated with discharge. During 1990-2015 (a period of a re-established market economy, reduced fertilization, ceased drainage, partial conversion of arable land to pastures, and increasing environmental protection), concentrations of SO 4 and NO 3 significantly decreased due to reduced agricultural production and atmospheric pollution, and their positive correlations with discharge disappeared. In contrast, Na and Cl concentrations increased due to more intensive road de-icing, and their concentrations became negatively correlated with discharge. Trends in phosphorus concentrations reflected changes in its input by both diffuse (fertilizers) and point (wastewater) sources and were discharge independent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of sodium chloride salinity on ecophysiological and biochemical parameters of oak seedlings (Quercus robur L.) from use of de-icing salts for winter road maintenance.

PubMed

Laffray, Xavier; Alaoui-Sehmer, Laurence; Bourioug, Mohamed; Bourgeade, Pascale; Alaoui-Sossé, Badr; Aleya, Lotfi

2018-04-04

Salt is widely used to melt snow on roads especially in mountain regions. Whether as rock salt or aerosols, spread or sprayed over road surfaces, salt may result in increased salt concentrations in soils, which, in turn, affect natural vegetation, especially tree seedlings already subjected to various other types of abiotic stress. The authors investigated the effects of salt treatment-related stress on seedling growth and certain biochemical parameters in Quercus robur to determine ion concentrations in root tips. Seedlings growing in a quartz sand/vermiculite mixture were subjected to NaCl concentrations of 0, 50, or 100 mM for 5 weeks. The results showed that high NaCl concentrations caused a marked reduction in total leaf biomass 55 and 75% for 50 and 100 mM treatments, respectively, in dry weight of stems (84%) and roots (175%) for 100 mM treatment and modified root architecture, whereas no changes appeared in leaf number. A non-significant decrease in relative water content, with changes in ion balance was recorded. Comparison of stressed to control plants show an increase in sodium (3.5-8-fold), potassium (0.6-fold), and chloride (9.5-14-fold) concentrations in the root tips while the K + /Na + ratio decreased. In taproots, no significant biochemical differences were observed between the salt-treated and the control plants for acid invertase activity, reducing sugars, sucrose, or soluble protein contents. The significance of ion and sugar accumulations in relation to osmotic adjustment and the ability of oak seedlings to cope with salt stress are discussed.

Ice-cored moraine degradation mapped and quantified using an unmanned aerial vehicle: A case study from a polythermal glacier in Svalbard

NASA Astrophysics Data System (ADS)

Tonkin, T. N.; Midgley, N. G.; Cook, S. J.; Graham, D. J.

2016-04-01

Ice-cored lateral-frontal moraines are common at the margins of receding high-Arctic valley glaciers, but the preservation potential of these features within the landform record is unclear. Recent climatic amelioration provides an opportunity to study the morphological evolution of these landforms as they de-ice. This is important because high-Arctic glacial landsystems have been used as analogues for formerly glaciated areas in the mid-latitudes. This study uses SfM (Structure-from-Motion) photogrammetry and a combination of archive aerial and UAV (unmanned aerial vehicle) derived imagery to investigate the degradation of an ice-cored lateral-frontal moraine at Austre Lovénbreen, Svalbard. Across the study area as a whole, over an 11-year period, the average depth of surface lowering was - 1.75 ± 0.89 m. The frontal sections of the moraine showed low or undetectable rates of change. Spatially variable rates of surface lowering are associated with differences in the quantity of buried ice within the structure of the moraine. Morphological change was dominated by surface lowering, with limited field evidence of degradation via back-wastage. This permits the moraine a greater degree of stability than previously observed at other sites in Svalbard. It is unclear whether the end point will be a fully stabilised ice-cored moraine, in equilibrium with its environment, or an ice-free lateral-frontal moraine complex. Controls on geomorphological change (e.g. topography and climate) and the preservation potential of the lateral-frontal moraine are discussed. The methods used by this research also demonstrate the potential value of SfM photogrammetry and unmanned aerial vehicles for monitoring environmental change and are likely to have wider applications in other geoscientific sub-disciplines.

Modelling geothermal conditions in part of the Szczecin Trough - the Chociwel area

NASA Astrophysics Data System (ADS)

Miecznik, Maciej; Sowiżdżał, Anna; Tomaszewska, Barbara; Pająk, Leszek

2015-09-01

The Chociwel region is part of the Szczecin Trough and constitutes the northeastern segment of the extended Szczecin-Gorzów Synclinorium. Lower Jurassic reservoirs of high permeability of up to 1145 mD can discharge geothermal waters with a rate exceeding 250 m3/h and temperatures reach over 90°C in the lowermost part of the reservoirs. These conditions provide an opportunity to generate electricity from heat accumulated in geothermal waters using binary ORC (Organic Rankine Cycle) systems. A numerical model of the natural state and exploitation conditions was created for the Chociwel area with the use of TOUGH2 geothermal simulator (i.e., integral finite-difference method). An analysis of geological and hydrogeothermal data indicates that the best conditions are found to the southeast of the town of Chociwel, where the bottom part of the reservoir reaches 3 km below ground. This would require drilling two new wells, namely one production and one injection. Simulated production with a flow rate of 275 m3/h, a temperature of 89°C at the wellhead, 30°C injection temperature and wells being 1.2 km separated from each other leads to a small temperature drop and moderate requirements for pumping power over a 50 years' time span. The ORC binary system can produce at maximum 592.5 kW gross power with the R227ea found as the most suitable working fluid. Geothermal brine leaving the ORC system with a temperature c. 53°C can be used for other purposes, namely mushroom growing, balneology, swimming pools, soil warming, de-icing, fish farming and for heat pumps.

The Distribution of Road Salt in Private Drinking Water Wells in a Southeastern New York Suburban Township.

PubMed

Kelly, Victoria R; Cunningham, Mary Ann; Curri, Neil; Findlay, Stuart E; Carroll, Sean M

2018-05-01

We used a GIS analysis of sodium and chloride concentrations in private water wells in a southeastern New York township to describe the pattern of distribution of road salt in aquifers tapped for drinking water. The primary source of road salt was sodium chloride, and sodium and chloride concentrations were significantly correlated ( = 0.80, < 0.01). Chloride concentrations in wells increased as the percentage of impervious surface cover (ISC) within a 250-m radius around wells increased ( = 0.87, < 0.01) and declined with increasing distance to the nearest road ( = 0.76, < 0.01). Wells that were located lower in elevation than the nearest road had higher concentrations of chloride than wells that were higher than the nearest road, but this occurred only when the nearest road was >30 m from the wells ( < 0.01). Chloride concentrations were not affected by well depth or adjacent road type (major or minor roads). Surface geology and hydrologic soil class had significant effects ( < 0.01) on chloride concentrations in wells, with porous surface geology types and well-drained soils having higher concentrations; these effects may be confounded by the fact that ISC was more likely to occur on these permeable surface geology and soil types. Hot and cold spot analysis revealed substantial unevenness in chloride concentrations. Results for sodium were similar to those for chloride. Overall, these results indicate that road salt contamination of groundwater is unevenly distributed and is affected by landscape factors that can be used to guide well testing and best management practices of deicing salt distribution. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Potential of combined Water Sensitive Urban Design systems for salinity treatment in urban environments.

PubMed

Kazemi, Fatemeh; Golzarian, Mahmood Reza; Myers, Baden

2018-03-01

Water sensitive urban design and similar concepts often recommend a 'treatment train' is employed to improve stormwater quality. In this study, the capability of a combined permeable pavement and bioretention basin was examined with a view to developing a permeable pavement reservoir that can supplement the irrigation needs of a bioretention system in semi-arid climates. Salinity was a key study parameter due to published data on salinity in permeable pavement storage, and the potential to harvest water contaminated with de-icing salts. To conduct experiments, roofwater was collected from a roof in Adelaide, South Australia. Water was amended with NaCl to produce a control runoff (no added salt), a medium (500 mg/l) and a high (1500 mg/l) salinity runoff. Water was then run through the pavement into the storage reservoir and used to irrigate the bioretention system. Samples were collected from the roof, the pavement reservoir and the bioretention system outflow to determine whether significant water quality impacts occurred. Results show that while salinity levels increased significantly as water passed through the pavement and through the bioretention system, the increase was beneficial for irrigation purposes as it was from Ca and Mg ions thus reducing the sodium absorption ratio to levels considered 'good' for irrigation in accordance with several guidelines. Permeable paving increased pH of water and this effect was prominent when the initial salt concentration increased. The study shows that permeable pavements with underlying storage can be used to provide supplementary irrigation for bioretention systems, but high initial salt concentrations may present constraints on beneficial use of stormwater. Copyright © 2017. Published by Elsevier Ltd.

Na/Cl molar ratio changes during a salting cycle and its application to the estimation of sodium retention in salted watersheds.

PubMed

Sun, Hongbing; Huffine, Maria; Husch, Jonathan; Sinpatanasakul, Leeann

2012-08-01

Using soil column experiments and data from natural watersheds, this paper analyzes the changes in Na/Cl molar ratios during a salting cycle of aqueous-soil systems. The soil column experiments involved introducing NaCl salt at various initial concentrations into multiple soil columns. At the start of a salting cycle in the column experiments, sodium was adsorbed more than chloride due to cation exchange processes. As a result, the initial Na/Cl molar ratio in column effluent was lower than 1, but increased thereafter. One-dimensional PHREEQC geochemical transport simulations also were conducted to further quantify these trends under more diverse scenarios. The experimentally determined Na/Cl molar ratio pattern was compared to observations in the annual salting cycle of four natural watersheds where NaCl is the dominant applied road deicing salt. Typically, Na/Cl molar ratios were low from mid-winter to early spring and increased after the bulk of the salt was flushed out of the watersheds during the summer, fall and early winter. The established relationship between the Na/Cl molar ratios and the amount of sodium retention derived from the column experiments and computer simulations present an alternative approach to the traditional budget analysis method for estimating sodium retention when the experimental and natural watershed patterns of Na/Cl molar ratio change are similar. Findings from this study enhance the understanding of sodium retention and help improve the scientific basis for future environmental policies intended to suppress the increase of sodium concentrations in salted watersheds. Copyright © 2012 Elsevier B.V. All rights reserved.

A comparison of selected models for estimating cable icing

NASA Astrophysics Data System (ADS)

McComber, Pierre; Druez, Jacques; Laflamme, Jean

In many cold climate countries, it is becoming increasingly important to monitor transmission line icing. Indeed, by knowing in advance of localized danger for icing overloads, electric utilities can take measures in time to prevent generalized failure of the power transmission network. Recently in Canada, a study was made to compare the estimation of a few icing models working from meteorological data in estimating ice loads for freezing rain events. The models tested were using only standard meteorological parameters, i.e. wind speed and direction, temperature and precipitation rate. This study has shown that standard meteorological parameters can only achieve very limited accuracy, especially for longer icing events. However, with the help of an additional instrument monitoring the icing rate intensity, a significant improvement in model prediction might be achieved. The icing rate meter (IRM) which counts icing and de-icing cycles per unit time on a standard probe can be used to estimate the icing intensity. A cable icing estimation is then made by taking into consideration the accretion size, temperature, wind speed and direction, and precipitation rate. In this paper, a comparison is made between the predictions of two previously tested models (one obtained and the other reconstructed from their description in the public literature) and of a model based on the icing rate meter readings. The models are tested against nineteen events recorded on an icing test line at Mt. Valin, Canada, during the winter season 1991-1992. These events are mostly rime resulting from in-cloud icing. However, freezing rain and wet snow events were also recorded. Results indicate that a significant improvement in the estimation is attained by using the icing rate meter data together with the other standard meteorological parameters.

Vertical and horizontal distributions of microbial abundances and enzymatic activities in propylene-glycol-affected soils.

PubMed

Biró, Borbála; Toscano, Giuseppe; Horváth, Nikoletta; Matics, Heléna; Domonkos, Mónika; Scotti, Riccardo; Rao, Maria A; Wejden, Bente; French, Helen K

2014-01-01

The natural microbial activity in the unsaturated soil is vital for protecting groundwater in areas where high loads of biodegradable contaminants are supplied to the surface, which usually is the case for airports using aircraft de-icing fluids (ADF) in the cold season. Horizontal and vertical distributions of microbial abundance were assessed along the western runway of Oslo Airport (Gardermoen, Norway) to monitor the effect of ADF dispersion with special reference to the component with the highest chemical oxygen demand (COD), propylene glycol (PG). Microbial abundance was evaluated by several biondicators: colony-forming units (CFU) of some physiological groups (aerobic and anaerobic heterotrophs and microscopic fungi), most probable numbers (MPN) of PG degraders, selected catabolic enzymatic activities (fluorescein diacetate (FDA) hydrolase, dehydrogenase, and β-glucosidase). High correlations were found between the enzymatic activities and microbial counts in vertical soil profiles. All microbial abundance indicators showed a steep drop in the first meter of soil depth. The vertical distribution of microbial abundance can be correlated by a decreasing exponential function of depth. The horizontal trend of microbial abundance (evaluated as total aerobic CFU, MPN of PG-degraders, and FDA hydrolase activity) assessed in the surface soil at an increasing distance from the runway is correlated negatively with the PG and COD loads, suggesting the relevance of other chemicals in the modulation of microbial growth. The possible role of potassium formate, component of runway de-icers, has been tested in the laboratory by using mixed cultures of Pseudomonas spp., obtained by enrichment with a selective PG medium from soil samples taken at the most contaminated area near the runway. The inhibitory effect of formate on the growth of PG degraders is proven by the reduction of biomass yield on PG in the presence of formate.

Permeable Asphalt: A New Tool to Reduce Road Salt Contamination of Groundwater in Urban Areas.

PubMed

Dietz, Michael E; Angel, Derek R; Robbins, Gary A; McNaboe, Lukas A

2017-03-01

Chloride contamination of groundwater in urban areas due to deicing is a well-documented phenomenon in northern climates. The objective of this study was to evaluate the effects of permeable pavement on degraded urban groundwater. Although low impact development practices have been shown to improve stormwater quality, no infiltration practice has been found to prevent road salt chlorides from entering groundwater. The few studies that have investigated chlorides in permeable asphalt have involved sampling directly beneath the asphalt; no research has looked more broadly at surrounding groundwater conditions. Monitoring wells were installed upgradient and downgradient of an 860 m 2 permeable asphalt parking lot at the University of Connecticut (Storrs, Connecticut). Water level and specific conductance were measured continuously, and biweekly samples were analyzed for chloride. Samples were also analyzed for sodium (Na), calcium (Ca), and magnesium (Mg). Analysis of variance analysis indicated a significantly (p < 0.001) lower geometric mean Cl concentration downgradient (303.7 mg/L) as compared to upgradient (1280 mg/L). Concentrations of all alkali metals increased upgradient and downgradient during the winter months as compared to nonwinter months, indicating that cation exchange likely occurred. Despite the frequent high peaks of chloride in the winter months as well as the increases in alkali metals observed, monitoring revealed lower Cl concentrations downgradient than upgradient for the majority of the year. These results suggest that the use of permeable asphalt in impacted urban environments with high ambient chloride concentrations can be beneficial to shallow groundwater quality, although these results may not be generalizable to areas with low ambient chloride concentrations. © 2016, National Ground Water Association.

A study on the fabrication of superhydrophobic iron surfaces by chemical etching and galvanic replacement methods and their anti-icing properties

NASA Astrophysics Data System (ADS)

Li, Kunquan; Zeng, Xingrong; Li, Hongqiang; Lai, Xuejun

2015-08-01

Hierarchical structures on iron surfaces were constructed by means of chemical etching by hydrochloric acid (HCl) solution or the galvanic replacement by silver nitrate (AgNO3) solution. The superhydrophobic iron surfaces were successfully prepared by subsequent hydrophobic modification with stearic acid. The superhydrophobic iron surfaces were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and water contact angle (WCA). The effects of reactive concentration and time on the microstructure and the wetting behavior were investigated. In addition, the anti-icing properties of the superhydrophobic iron surfaces were also studied. The FTIR study showed that the stearic acid was chemically bonded onto the iron surface. With the HCl concentration increase from 4 mol/L to 8 mol/L, the iron surface became rougher with a WCA ranging from 127° to 152°. The AgNO3 concentration had little effect on the wetting behavior, but a high AgNO3 concentration caused Ag particle aggregates to transform from flower-like formations into dendritic crystals, owing to the preferential growth direction of the Ag particles. Compared with the etching method, the galvanic replacement method on the iron surface more favorably created roughness required for achieving superhydrophobicity. The superhydrophobic iron surface showed excellent anti-icing properties in comparison with the untreated iron. The icing time of water droplets on the superhydrophobic surface was delayed to 500 s, which was longer than that of 295 s for untreated iron. Meanwhile, the superhydrophobic iron surface maintained superhydrophobicity after 10 icing and de-icing cycles in cold conditions.

Oxygen demand of aircraft and airfield pavement deicers and alternative freezing point depressants

USGS Publications Warehouse

Corsi, Steven R.; Mericas, Dean; Bowman, George

2012-01-01

Aircraft and pavement deicing formulations and other potential freezing point depressants were tested for biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Propylene glycol-based aircraft deicers exhibited greater BOD5 than ethylene glycol-based aircraft deicers, and ethylene glycol-based products had lower degradation rates than propylene glycol-based products. Sodium formate pavement deicers had lower COD than acetate-based pavement deicers. The BOD and COD results for acetate-based pavement deicers (PDMs) were consistently lower than those for aircraft deicers, but degradation rates were greater in the acetate-based PDM than in aircraft deicers. In a 40-day testing of aircraft and pavement deicers, BOD results at 20°C (standard) were consistently greater than the results from 5°C (low) tests. The degree of difference between standard and low temperature BOD results varied among tested products. Freshwater BOD test results were not substantially different from marine water tests at 20°C, but glycols degraded slower in marine water than in fresh water for low temperature tests. Acetate-based products had greater percentage degradation than glycols at both temperatures. An additive component of the sodium formate pavement deicer exhibited toxicity to the microorganisms, so BOD testing did not work properly for this formulation. BOD testing of alternative freezing point depressants worked well for some, there was little response for some, and for others there was a lag in response while microorganisms acclimated to the freezing point depressant as a food source. Where the traditional BOD5 test performed adequately, values ranged from 251 to 1,580 g/kg. Where the modified test performed adequately, values of BOD28 ranged from 242 to 1,540 g/kg.

Cation exchange in a glacial till drumlin at a road salt storage facility

NASA Astrophysics Data System (ADS)

Ostendorf, David W.; Xing, Baoshan; Kallergis, Niki

2009-05-01

We use laboratory and field data to calibrate existing geochemical and transport models of cation exchange induced by contamination of an unconfined aquifer at a road salt storage facility built upon a glacial till drumlin in eastern Massachusetts. A Gaines and Thomas selectivity coefficient K models the equilibrium sodium and divalent cation distribution in the groundwater and solid matrix, while an existing method of characteristics model describes the advective transport of total dissolved cations and sorbed sodium. Laboratory isotherms of split spoon soil samples from the drumlin calibrate K with an average value of 0.0048 (L/g) 1/2 for a measured cation exchange capacity of 0.057 meq/g dry soil. Ten years of monitoring well data document groundwater flow and the advection of conservative chloride due to outdoor storage and handling of road salt at the site. The monitoring well cation data and retarded transport model offer an independent K calibration of 0.0040 to 0.0047 (L/g) 1/2: the consistency of the field and laboratory selectivity coefficient calibrations endorse this application of the Gaines and Thomas and method of characteristics models. The advancing deicing agent plume releases divalent cations from the till into the groundwater, so that monitoring well samples do not reflect the chemical composition of the road salt. In this regard, dissolved divalent cation milliequivalent concentrations are as high as 80% of the total dissolved cationic concentrations in the salt contaminated monitoring well samples, far greater than their 2.5% level in the road salt stored at the site. Cation exchange can thus obscure attempts to hindcast stored road salt sodium water table concentration from monitoring well sample stoichiometry, or to predict sodium impacts on groundwater or receiving stream quality downgradient of the well.

Cation exchange in a glacial till drumlin at a road salt storage facility.

PubMed

Ostendorf, David W; Xing, Baoshan; Kallergis, Niki

2009-05-12

We use laboratory and field data to calibrate existing geochemical and transport models of cation exchange induced by contamination of an unconfined aquifer at a road salt storage facility built upon a glacial till drumlin in eastern Massachusetts. A Gaines and Thomas selectivity coefficient K models the equilibrium sodium and divalent cation distribution in the groundwater and solid matrix, while an existing method of characteristics model describes the advective transport of total dissolved cations and sorbed sodium. Laboratory isotherms of split spoon soil samples from the drumlin calibrate K with an average value of 0.0048 (L/g)(1/2) for a measured cation exchange capacity of 0.057 meq/g dry soil. Ten years of monitoring well data document groundwater flow and the advection of conservative chloride due to outdoor storage and handling of road salt at the site. The monitoring well cation data and retarded transport model offer an independent K calibration of 0.0040 to 0.0047 (L/g)(1/2): the consistency of the field and laboratory selectivity coefficient calibrations endorse this application of the Gaines and Thomas and method of characteristics models. The advancing deicing agent plume releases divalent cations from the till into the groundwater, so that monitoring well samples do not reflect the chemical composition of the road salt. In this regard, dissolved divalent cation milliequivalent concentrations are as high as 80% of the total dissolved cationic concentrations in the salt contaminated monitoring well samples, far greater than their 2.5% level in the road salt stored at the site. Cation exchange can thus obscure attempts to hindcast stored road salt sodium water table concentration from monitoring well sample stoichiometry, or to predict sodium impacts on groundwater or receiving stream quality downgradient of the well.

Chloride Sources and Losses in Two Tile-Drained Agricultural Watersheds.

PubMed

David, Mark B; Mitchell, Corey A; Gentry, Lowell E; Salemme, Ronald K

2016-01-01

Chloride is a relatively unreactive plant nutrient that has long been used as a biogeochemical tracer but also can be a pollutant causing aquatic biology impacts when concentrations are high, typically from rock salt applications used for deicing roads. Chloride inputs to watersheds are most often from atmospheric deposition, road salt, or agricultural fertilizer, although studies on agricultural watersheds with large fertilizer inputs are few. We used long-term (21 and 17 yr) chloride water quality data in two rivers of east-central Illinois to better understand chloride biogeochemistry in two agricultural watersheds (Embarras and Kaskaskia), the former with a larger urban land use and both with extensive tile drainage. During our sampling period, the average chloride concentration was 23.7 and 20.9 mg L in the Embarras and Kaskaskia Rivers, respectively. Annual fluxes of chloride were 72.5 and 61.2 kg ha yr in the Embarras and Kaskaskia watersheds, respectively. In both watersheds, fertilizer chloride was the dominant input (∼49 kg ha yr), with road salt likely the other major source (23.2 and 7.2 kg ha yr for the Embarras and Kaskaskia watersheds, respectively). Combining our monitoring data with earlier published data on the Embarras River showed an increase in chloride concentrations as potash use increased in Illinois during the 1960s and 1970s with a lag of about 2 to 6 yr to changes in potash inputs based on a multiple-regression model. In these agricultural watersheds, riverine chloride responds relatively quickly to potash fertilization as a result of tile-drainage. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Anti-icing properties of superhydrophobic ZnO/PDMS composite coating

NASA Astrophysics Data System (ADS)

Yang, Chao; Wang, Fajun; Li, Wen; Ou, Junfei; Li, Changquan; Amirfazli, Alidad

2016-01-01

We present the excellent anti-icing performance for a superhydrophobic coating surface based on ZnO/polydimethylsiloxane (ZnO/PDMS) composite. The superhydrophobic ZnO/PDMS coating surface was prepared by a facile solution mixing, drop coating, room-temperature curing and surface abrading procedure. The superhydrophobic ZnO/PDMS composite coating possesses a water contact angle of 159.5° and a water sliding angle of 8.3° at room temperature (5 °C). The anti-icing properties of the superhydrophobic coating were investigated by continuously dropping cold-water droplets (about 0 °C) onto the pre-cooled surface using a home-made apparatus. The sample was placed at different tilting angle (0° and 10°) and pre-cooled to various temperatures (-5, -10 and -15 °C) prior to measure. The pure Al surface was also studied for comparison. It was found that icing accretion on the surface could be reduced apparently because the water droplets merged together and slid away from the superhydrophobic surface at all of the measuring temperatures when the surface is horizontally placed. In addition, water droplet slid away completely from the superhydrophobic surface at -5 and -10 °C when the surface is tilted at 10°, which demonstrates its excellent anti-icing properties at these temperatures. When the temperature decreased to -15 °C, though ice accretion on the tilted superhydrophobic coating surface could not be avoided absolutely, the amount of ice formed on the surface is very small, which indicated that the coating surface with superhydrophobicity could significantly reduce ice accumulation on the surface at very low temperature (-15 °C). Importantly, the sample is also stable against repeated icing/deicing cycles. More meaningfully, once the superhydrophobic surface is damaged, it can be repaired easily and rapidly.

Effects of Highway Road Salting on the Water Quality of Selected Streams in Chittenden County, Vermont, November 2005-2007

USGS Publications Warehouse

Denner, Jon C.; Clark, Stewart F.; Smith, Thor E.; Medalie, Laura

2010-01-01

A study of road-deicing chloride (Cl) concentrations and loads was conducted at three streams in Chittenden County, VT, from November 2005 to 2007. This study was done by the U.S. Geological Survey, in cooperation with the Vermont Agency of Transportation. The streams, Alder Brook, Allen Brook, and Mill Brook, were selected to represent different land uses in the upstream watershed, different road types and densities, and different geometric patterns of the roadway draining to the receiving stream to assess the relative contribution of and differences in state road-salt applications to stream Cl concentrations and loads. Water-quality samples were collected and specific conductance was measured continuously at paired stations upstream and downstream from State highways and related to Cl concentrations to assist in determining the effects of road-salting operations during winter maintenance on the levels of Cl in the streams. Mean concentrations of Cl ranged from 8.2 to 72 mg/L (milligrams per liter) in the water-quality samples collected at sampling stations upstream from State highway bridges and from 7.9 to 80 mg/L in those collected at sampling stations downstream of highway bridges. Mean Cl loads ranged from 1,100 to 4,090 lb/d (pounds per day) at upstream stations and from 1,110 to 4,200 lb/d at downstream stations. Estimated mean annual Cl loads ranged from 402,000 to 1,490,000 lb/yr (pounds per year) at upstream stations and from 405,000 to 1,530,000 lb/yr at downstream stations. Mean Cl concentrations in samples collected at the three paired stations were lowest at Mill Brook at VT 117 near Essex Junction, VT (7.9 mg/L) and highest at Allen Brook at VT 2A near Essex Junction, VT (80.7 mg/L). None of the monitored Cl concentrations in the water-quality samples collected at the three paired sampling stations exceeded either of the U.S. Environmental Protection Agency's (USEPA) recommended chronic and acute Cl toxicity criteria of 230 and 860 mg/L, respectively. A fourth stream site, a small tributary draining to Alder Brook between the upstream and downstream stations, was monitored from December 2006 to November 2007. This tributary collected runoff from a state highway and an interchange before flowing through a wetlands retention basin. The mean Cl concentration in water-quality samples collected at the tributary was 449 mg/L. The USEPA recommended chronic toxicity criterion of 230 mg/L was exceeded about 65 percent of the monitoring period. The USEPA recommended acute toxicity criterion of 860 mg/L was not exceeded. Estimated Cl loads below the State highway bridges exceeded loads above the bridges at all three paired stations during both years of the study. The differences in the annual loads between the upstream and downstream stations were 0.7, 3.0 and 14 percent at Mill, Allen, and Alder Brooks, respectively. Almost all of the difference (92 percent) at Alder Brook was due to the tributary. Cl applied by the State of Vermont for deicing purposes represented less than 20 percent of the annual estimated Cl load in all 3 streams below the state highways. The highest monthly Cl loads during the first year of the study were observed in January 2006 at all three stream stations because of an early snowmelt event. The highest monthly Cl loads during the second year of the study were observed in April 2007 at all three streams during spring snowmelt and were followed by decrease in Cl loading through the summer. Generally, the relation of Cl loads to runoff was similar at all three streams. In July and October 2007, loads increased slightly with an increase in runoff, indicating that Cl in the soils and groundwater may be contributing to the Cl levels during the summer and fall, well after the road-salting season. Cl loads in all three streams appear to be due primarily to sources in the watersheds upstream of the state highway bridge where road salt was applied and (or) Cl retained in soils and streambed

Environmental challenge as a geologist

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, B.M.

1994-12-31

Many scientific environmental studies involving geology are now becoming apparent. If we can convince the regulatory agencies to take advantage of our geologic knowledge to assess environmental problems, many unnecessary mandates can be modified. Isn`t it strange that Mt. Erebus in the Antarctic pumps over 1,000 tons of chlorine directly into the vortex of the earth every day and has for over 100 years? Yet man and CFCs (chlorofluorocarbons) are being blamed for the ozone hole and global warming. Recent ice cores have been recovered in Greenland which date back 250,000 years in time. This scientific study indicated that themore » climate in the northern hemisphere has always been cyclic. The United States Geological Survey has recently completed a study of the Exxon Valdes oil spill and has found Monterey oil residues are more prevalent than the North Slope oil. The Monterey oil is present as a result of the 1994 Alaska earthquake. Also current activity by fishing boats is polluting much of the Prince William Sound. Geologists have studied the effects of road deicing in the northeast and have reported that there is substantial evidence that the millions of tons of salt placed on the highways are contributing to underground water pollution. Yet the oil industry is being challenged by environmental groups that putting produced salt water back into disposal wells is contaminating and polluting the country. We need a level playing field. How can all this help a petroleum geologist? To be competitive in today`s business, we must take advantage of opportunities to learn about other sub-disciplines of our profession. Many geologists are in a survival mode, and additional education and training are necessary if we are to survive. Technical transfers from hydrocarbon extraction to environmental assessment can be undertaken if there is a desire to change. Reeducation can be achieved by an optimistic, aggressive and disciplined individual.« less

Where Does Road Salt Go - a Static Salt Model

NASA Astrophysics Data System (ADS)

Yu, C. W.; Liu, F.; Moriarty, V. W.

2017-12-01

Each winter, more than 15 million tons of road salt is applied in the United States for the de-icing purpose. Considerable amount of chloride in road salt flows into streams/drainage systems with the snow melt runoff and spring storms, and eventually goes into ecologically sensitive low-lying areas in the watershed, such as ponds and lakes. In many watersheds in the northern part of US, the chloride level in the water body has increased significantly in the past decades, and continues an upward trend. The environmental and ecological impact of the elevated chloride level can no longer be ignored. However although there are many studies on the biological impact of elevated chloride levels, there are few investigations on how the spatially distributed road salt application affects various parts of the watershed. In this presentation, we propose a static road salt model as a first-order metric to address spacial distribution of salt loading. Derived from the Topological Wetness Index (TWI) in many hydrological models, this static salt model provides a spatial impact as- sessment of road salt applications. To demonstrate the effectiveness of the static model, National Elevation Dataset (NED) of ten-meter resolution of Lake George watershed in New York State is used to generate the TWI, which is used to compute a spatially dis- tributed "salt-loading coefficient" of the whole watershed. Spatially varying salt applica- tion rate is then aggregated, using the salt-loading coefficients as weights, to provide salt loading assessments of streams in the watershed. Time-aggregated data from five CTD (conductivity-temperature-depth) sensors in selected streams are used for calibration. The model outputs and the sensor data demonstrate a strong linear correlation, with the R value of 0.97. The investigation shows that the static modeling approach may provide an effective method for the understanding the input and transport of road salt to within watersheds.

Sputum rheology changes in cystic fibrosis lung disease following two different types of physiotherapy: flutter vs autogenic drainage.

PubMed

App, E M; Kieselmann, R; Reinhardt, D; Lindemann, H; Dasgupta, B; King, M; Brand, P

1998-07-01

The aim of the present study was to investigate the efficacy of two frequently used physiotherapies (PTs) for the removal of bronchial secretions in cystic fibrosis (CF) lung disease: autogenic drainage (AD) and the Flutter (Desitin in Germany). AD is believed to improve mucus clearance from peripheral to central airways due to airway caliber changes in combination with a special breathing technique. The Flutter is an easy-to-use physiotherapy device based on oscillations of a steel ball during expiration through a pipe-type device. To evaluate the acute and chronic physiotherapy effects of these two techniques, 14 CF patients underwent either twice daily AD or Flutter treatment for 4 consecutive weeks in a randomized crossover design. Prior to each therapy interval, for a 1-week wash-out period, no PT was administered, but patients continued regular medication. At the beginning and end of each 4-week interval, pulmonary function was measured before and after an acute 30-min therapy. At the end of the PT session, sputum was collected, weighed, and deep frozen until analyzed. The viscoelasticity of the sputum was evaluated using a magnetic microrheometer. No significant changes were noted for FVC, FEV1, or sputum volume throughout the study. Sputum viscoelasticity (rigidity index), however, was significantly lower (p<0.01) after therapy with the Flutter in comparison with AD, predicting improvements in mucociliary and cough clearability of the secretions. In a companion in vitro experiment, oscillations generated by passing humidified air over CF sputum lining an acrylic tube connected to a Flutter de-ice were found to decrease sputum elasticity, as measured by a filancemeter. These findings suggest that applied oscillations are capable of decreasing mucus viscoelasticity within the airways at frequencies and amplitudes achievable with the Flutter device, and provide direct evidence that PT can reduce the viscoelasticity of sputum.

Hydroxyapatite Nanowire-Based All-Weather Flexible Electrically Conductive Paper with Superhydrophobic and Flame-Retardant Properties.

PubMed

Chen, Fei-Fei; Zhu, Ying-Jie; Xiong, Zhi-Chao; Dong, Li-Ying; Chen, Feng; Lu, Bing-Qiang; Yang, Ri-Long

2017-11-15

How to survive under various harsh working conditions is a key challenge for flexible electronic devices because their performances are always susceptible to environments. Herein, we demonstrate the novel design and fabrication of a new kind of the all-weather flexible electrically conductive paper based on ultralong hydroxyapatite nanowires (HNs) with unique combination of the superhydrophobic surface, electrothermal effect, and flame retardancy. The superhydrophobic surface with water repellency stabilizes the electrically conductive performance of the paper in water. For example, the electrical current through the superhydrophobic paper onto which water droplets are deposited shows a little change (0.38%), and the electrical performance is steady as well even when the paper is immersed in water for 120 s (just 3.65% change). In addition, the intrinsic electrothermal effect of the electrically conductive paper can efficiently heat the paper to reach a high temperature, for example, 224.25 °C, within 10 s. The synergistic effect between the electrothermal effect and superhydrophobic surface accelerates the melting and removal of ice on the heated electrically conductive paper. Deicing efficiency of the heated superhydrophobic electrically conductive paper is ∼4.5 times that of the unheated superhydrophobic electrically conductive paper and ∼10.4 times that of the heated superhydrophilic paper. More importantly, benefiting from fire-resistant ultralong HNs, thermally stable Ketjen black, and Si-O backbone of poly(dimethylsiloxane), we demonstrate the stable and continuous service of the as-prepared electrically conductive paper in the flame for as long as 7 min. The electrical performance of the electrically conductive paper after flame treatment can maintain as high as 90.60% of the original value. The rational design of the electrically conductive paper with suitable building materials and structure demonstrated here will give an inspiration for the development of new kinds of all-weather flexible electronic devices that can work under harsh conditions.

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

DOE PAGES

Herbert, Ellen R.; Boon, Paul; Burgin, Amy J.; ...

2015-10-29

Salinization, a widespread threat to the structure and ecological functioning of inland and coastal wetlands, is currently occurring at an unprecedented rate and geographic scale. The causes of salinization are diverse and include alterations to freshwater flows, land-clearance, irrigation, disposal of wastewater effluent, sea level rise, storm surges, and applications of de-icing salts. Climate change and anthropogenic modifications to the hydrologic cycle are expected to further increase the extent and severity of wetland salinization. Salinization alters the fundamental physicochemical nature of the soil-water environment, increasing ionic concentrations and altering chemical equilibria and mineral solubility. Increased concentrations of solutes, especially sulfate,more » alter the biogeochemical cycling of major elements including carbon, nitrogen, phosphorus, sulfur, iron, and silica. The effects of salinization on wetland biogeochemistry typically include decreased inorganic nitrogen removal (with implications for water quality and climate regulation), decreased carbon storage (with implications for climate regulation and wetland accretion), and increased generation of toxic sulfides (with implications for nutrient cycling and the health/functioning of wetland biota). Indeed, increased salt and sulfide concentrations induce physiological stress in wetland biota and ultimately can result in large shifts in wetland communities and their associated ecosystem functions. The productivity and composition of freshwater species assemblages will be highly altered, and there is a high potential for the disruption of existing interspecific interactions. Although there is a wealth of information on how salinization impacts individual ecosystem components, relatively few studies have addressed the complex and often non-linear feedbacks that determine ecosystem-scale responses or considered how wetland salinization will affect landscape-level processes. Although the salinization of wetlands may be unavoidable in many cases, these systems may also prove to be a fertile testing ground for broader ecological theories including (but not limited to): investigations into alternative stable states and tipping points, trophic cascades, disturbance-recovery processes, and the role of historical events and landscape context in driving community response to disturbance.« less

Geobacter bemidjiensis sp. nov. and Geobacter psychrophilus sp. nov., two novel Fe(III)-reducing subsurface isolates

USGS Publications Warehouse

Nevin, Kelly P.; Holmes, Dawn E.; Woodard, Trevor L.; Hinlein, Erich S.; Ostendorf, David W.; Lovely, Derek R.

2005-01-01

Fe(III)-reducing isolates were recovered from two aquifers in which Fe(III) reduction is known to be important. Strain BemT was enriched from subsurface sediments collected in Bemidji, MN, USA, near a site where Fe(III) reduction is important in aromatic hydrocarbon degradation. Strains P11, P35T and P39 were isolated from the groundwater of an aquifer in Plymouth, MA, USA, in which Fe(III) reduction is important because of long-term inputs of acetate as a highway de-icing agent to the subsurface. All four isolates were Gram-negative, slightly curved rods that grew best in freshwater media. Strains P11, P35T and P39 exhibited motility via means of monotrichous flagella. Analysis of the 16S rRNA and nifD genes indicated that all four strains are δ-proteobacteria and members of the Geobacter cluster of the Geobacteraceae. Differences in phenotypic and phylogenetic characteristics indicated that the four isolates represent two novel species within the genus Geobacter. All of the isolates coupled the oxidation of acetate to the reduction of Fe(III) [iron(III) citrate, amorphous iron(III) oxide, iron(III) pyrophosphate and iron(III) nitrilotriacetate]. All four strains utilized ethanol, lactate, malate, pyruvate and succinate as electron donors and malate and fumarate as electron acceptors. Strain BemT grew fastest at 30 °C, whereas strains P11, P35T and P39 grew equally well at 17, 22 and 30 °C. In addition, strains P11, P35T and P39 were capable of growth at 4 °C. The names Geobacter bemidjiensis sp. nov. (type strain BemT=ATCC BAA-1014T=DSM 16622T=JCM 12645T) and Geobacter psychrophilus sp. nov. (strains P11, P35T and P39; type strain P35T=ATCC BAA-1013T=DSM 16674T=JCM 12644T) are proposed.

Turboprop aircraft performance response to various environmental conditions

NASA Astrophysics Data System (ADS)

Ashenden, Russell Allen

1997-10-01

This study evaluated aircraft and airfoil performance response to various environmental conditions. These conditions included clear air, warm rain, ice only, mixed phase and supercooled drops encountered during 19 separate flights. Supercooled droplets consisting of cloud, drizzle and rain sizes were the main focus of this study. Aircraft response was quantified by rates of change in aircraft rate-of-climb capability, lift and drag coefficients and lift over drag ratio. Airfoil degradation due to simulated ice shapes and drizzle ice roughness was measured in a wind tunnel for comparison. The aircraft performance parameters were compared to environmental hydrometeor parameters quantifying the environmental conditions. Results show that encounters with supercooled drizzle drops, or SCDD, resulted in maximum rates of performance degradation. These high rates of degradation forced the pilot to take evasive action within 5 minutes of entering these hazardous conditions. Encounters with supercooled cloud and rain sized drops resulted in minor to low rates of performance degradation whereas encounters with supercooled drops in low ice particle concentrations resulted in only minor rates of degradation. In addition, aircraft response to high ice particle concentrations and low liquid water, following an SCDD encounter, resulted in rapid performance recovery. The airfoil evaluations show similar results where the drizzle drop ice shape and simulated drizzle ice roughness resulted in the highest performance degradation. These evaluations also show that the most sensitive surface location is on the suction side between 6 and at least 11% of airfoil chord. Ice contaminations in this area are beyond the protective de-icing boots of most aircraft and lead to severe degradations in lift and drag characteristics. The results presented herein show a strong relationship between aircraft response and environmental parameters utilizing the larger drops in the hydrometeor distribution. The results suggest that the most severe icing is actually caused by drizzle sized drops as opposed to freezing rain. Furthermore, these results are similar to many twin-turboprop aircraft typically utilized by the commuter fleet.

Use of bromide:Chloride ratios to differentiate potential sources of chloride in a shallow, unconfined aquifer affected by brackish-water intrusion

USGS Publications Warehouse

Andreasen, D.C.; Fleck, W.B.

1997-01-01

Brackish water from Chesapeake Bay and its tributaries has entered the Aquia aquifer in east-central Anne Arundel County, Maryland, USA. This determination was made based on chloride analyses of water samples collected in wells screened in the Aquia aquifer between October 1988 and May 1989. The Aquia aquifer, which is composed of fine- to medium-grained sand, is a shallow, unconfined aquifer in this area. Land use is primarily urban, consisting of a mixture of residential and light commercial areas. Associated with the urban setting is the potential for chloride contamination to enter the Aquia aquifer from anthropogenic sources, such as residential septic-tank effluent, leaky public sewer lines, road-deicing salt, stormwater infiltration basins, and domestic water-conditioning recharge effluent. In order to map the distribution of bay-water intrusion in the Aquia aquifer, chloride derived from Chesapeake Bay was differentiated from chloride derived from anthropogenic sources by comparing the ratio of dissolved bromide to dissolved chloride (bromide:chloride) in groundwater to the distinctive ratio in Chesapeake Bay water. Two additional factors considered in determining the source of the chloride were nitrogen concentrations and well-screen positions of sampled wells in relation to the estimated depth of the fresh-water/brackish-water interface. Of 36 Aquia-aquifer water samples with chloride concentrations greater than 30 mg/L, 22 had bromide:chloride ratios similar to the ratio in Chesapeake Bay water, an indication that bay water is the primary source of the chloride. Of the other 14 samples with bromide:chloride ratios dissimilar to the ratio in Chesapeake Bay water, seven were from wells where screen positions were substantially above the estimated fresh-water/brackish-water interface. Three of these samples had nitrogen concentrations (as nitrite plus nitrate) greater than 3.0 mg/L, an indication that chloride in these groundwater samples comes from anthropogenic sources, at least in part.

Effects of urbanization on stream water quality in the city of Atlanta, Georgia, USA

USGS Publications Warehouse

Peters, N.E.

2009-01-01

A long-term stream water quality monitoring network was established in the city of Atlanta, Georgia during 2003 to assess baseline water quality conditions and the effects of urbanization on stream water quality. Routine hydrologically based manual stream sampling, including several concurrent manual point and equal width increment sampling, was conducted ???12 times annually at 21 stations, with drainage areas ranging from 3.7 to 232 km2. Eleven of the stations are real-time (RT) stations having continuous measures of stream stage/ discharge, pH, dissolved oxygen, specific conductance, water temperature and turbidity, and automatic samplers for stormwater collection. Samples were analyzed for field parameters, and a broad suite of water quality and sediment-related constituents. Field parameters and concentrations of major ions, metals, nutrient species and coliform bacteria among stations were evaluated and with respect to watershed characteristics and plausible sources from 2003 through September 2007. Most constituent concentrations are much higher than nearby reference streams. Concentrations are statistically different among stations for several constituents, despite high variability both within and among stations. Routine manual sampling, automatic sampling during stormflows and RT water quality monitoring provided sufficient information about urban stream water quality variability to evaluate causes of water quality differences among streams. Fecal coliform bacteria concentrations of most samples exceeded Georgia's water quality standard for any water-usage class. High chloride concentrations occur at three stations and are hypothesized to be associated with discharges of chlorinated combined sewer overflows, drainage of swimming pool(s) and dissolution and transport during rainstorms of CaCl2, a deicing salt applied to roads during winter storms. One stream was affected by dissolution and transport of ammonium alum [NH4Al(SO4)2] from an alum-manufacturing plant; streamwater has low pH (<5), low alkalinity and high metals concentrations. Several trace metals exceed acute and chronic water quality standards and high concentrations are attributed to washoff from impervious surfaces.

Impact of chloride on denitrification potential in roadside wetlands.

PubMed

Lancaster, Nakita A; Bushey, Joseph T; Tobias, Craig R; Song, Bongkeun; Vadas, Timothy M

2016-05-01

Developed landscapes are exposed to changes in hydrology and water chemistry that limit their ability to mitigate detrimental impacts to coastal water bodies, particularly those that result from stormwater runoff. The elevated level of impervious cover increases not only runoff but also contaminant loading of nutrients, metals, and road salt used for deicing to water bodies. Here we investigate the impact that road salt has on denitrification in roadside environments. Sediments were collected from a series of forested and roadside wetlands and acclimated with a range of Cl(-) concentrations from 0 to 5000 mg L(-1) for 96 h. Denitrification rates were measured by the isotope pairing technique using (15)N-NO3(-), while denitrifying community structures were compared using terminal restriction fragment length polymorphism (T-RFLP) of nitrous oxide reductase genes (nosZ). Chloride significantly (p < 0.05) inhibited denitrification in forested wetlands at a Cl(-) dosage of 2500 or 5000 mg L(-1), but the decrease in denitrification rates was less and not significant for the roadside wetlands historically exposed to elevated concentrations of Cl(-). The difference could not be attributed to other significant changes in conditions, such as DOC concentrations, N species concentrations, or pH levels. Denitrifying communities, as measured by T-RFs of the nosZ gene, in the roadside wetlands with elevated concentration of Cl(-) were distinctly different and more diverse compared to forested wetlands, and also different in roadside wetlands after 96 h exposures to Cl(-). The shifts in denitrifying communities seem to minimize the decrease in denitrification rates in the wetlands previously exposed to Cl. As development results in more Cl(-) use and exposure to a broad range of natural or manmade wetland structures, an understanding of the seasonal effect of Cl on denitrification processes in these systems would aid in design or mitigation of the effects on N removal rates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Material characterization for morphing purposes in order to match flight requirements

NASA Astrophysics Data System (ADS)

Geier, Sebastian; Kintscher, Markus; Heintze, Olaf; Wierach, Peter; Monner, Hans-Peter; Wiedemann, Martin

2012-04-01

Natural laminar flow is one of the challenging aims of the current aerospace research. Main reasons for the aerodynamic transition from laminar into turbulent flow focusing on the airfoil-structure is the aerodynamic shape and the surface roughness. The Institute of Composite Structures and Adaptive Systems at the German Aerospace Center in Braunschweig works on the optimization of the aerodynamic-loaded structure of future aircrafts in order to increase their efficiency. Providing wing structures suited for natural laminar flow is a step towards this goal. Regarding natural laminar flow, the structural design of the leading edge of a wing is of special interest. An approach for a gap-less leading edge was developed to provide a gap- and step-less high quality surface suited for natural laminar flow and to reduce slat noise. In a national project the first generation of the 3D full scale demonstrator was successfully tested in 2010. The prototype consists of several new technologies, opening up the issue of matching the long and challenging list of airworthiness requirements simultaneously. Therefore the developed composite structure was intensively tested for further modifications according to meet requirements for abrasion, impact and deicing basically. The former presented structure consists completely of glass-fiber-prepreg (GFRP-prepreg). New functions required the addition of a new material-mix, which has to fit into the manufacturing-chain of the composite structure. In addition the hybrid composites have to withstand high loadings, high bending-induced strains (1%) and environmentally influenced aging. Moreover hot-wet cycling tests are carried out for the basic GFRP-structure in order to simulate the long term behavior of the material under extrem conditions. The presented paper shows results of four-points-bending-tests of the most critical section of the morphing leading edge device. Different composite-hybrids are built up and processed. An experimental based trend towards an optimized material design will be shown.

Organic chemical degradation by remote study of the redox conditions

NASA Astrophysics Data System (ADS)

Fernandez, P. M.; Revil, A.; Binley, A. M.; Bloem, E.; French, H. K.

2014-12-01

Monitoring the natural (and enhanced) degradation of organic contaminants is essential for managing groundwater quality in many parts of the world. Contaminated sites often have limited access, hence non-intrusive methods for studying redox processes, which drive the degradation of organic compounds, are required. One example is the degradation of de-icing chemicals (glycols and organic salts) released to the soil near airport runways during winter. This issue has been broadly studied at Oslo airport, Gardermoen, Norway using intrusive and non-intrusive methods. Here, we report on laboratory experiments that aim to study the potential of using a self-potential, DCresistivity, and time-domain induced polarization for geochemical characterization of the degradation of Propylene Glycol (PG). PG is completely miscible in water, does not adsorb to soil particles and does not contribute to the electrical conductivity of the soil water. When the contaminant is in the unsaturated zone near the water table, the oxygen is quickly consumed and the gas exchange with the surface is insufficient to ensure aerobic degradation, which is faster than anaerobic degradation. Since biodegradation of PG is highly oxygen demanding, anaerobic pockets can exist causing iron and manganese reduction. It is hypothesised that nitrate would boost the degradation rate under such conditions. In our experiment, we study PG degradation in a sand tank. We provide the system with an electron highway to bridge zones with different redox potential. This geo-battery system is characterized by self-potential, resistivity and induced polarization anomalies. An example of preliminary results with self-potential at two different times of the experiment can be seen in the illustration. These will be supplemented with more direct information on the redox chemistry: in-situ water sampling, pH, redox potential and electrical conductivity measurements. In parallel, a series of batch experiments have been performed to study anoxic microbial degradation using gas and resistivity measurements.

A global perspective on wetland salinization: ecological consequences of a growing threat to freshwater wetlands

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herbert, Ellen R.; Boon, Paul; Burgin, Amy J.

Salinization, a widespread threat to the structure and ecological functioning of inland and coastal wetlands, is currently occurring at an unprecedented rate and geographic scale. The causes of salinization are diverse and include alterations to freshwater flows, land-clearance, irrigation, disposal of wastewater effluent, sea level rise, storm surges, and applications of de-icing salts. Climate change and anthropogenic modifications to the hydrologic cycle are expected to further increase the extent and severity of wetland salinization. Salinization alters the fundamental physicochemical nature of the soil-water environment, increasing ionic concentrations and altering chemical equilibria and mineral solubility. Increased concentrations of solutes, especially sulfate,more » alter the biogeochemical cycling of major elements including carbon, nitrogen, phosphorus, sulfur, iron, and silica. The effects of salinization on wetland biogeochemistry typically include decreased inorganic nitrogen removal (with implications for water quality and climate regulation), decreased carbon storage (with implications for climate regulation and wetland accretion), and increased generation of toxic sulfides (with implications for nutrient cycling and the health/functioning of wetland biota). Indeed, increased salt and sulfide concentrations induce physiological stress in wetland biota and ultimately can result in large shifts in wetland communities and their associated ecosystem functions. The productivity and composition of freshwater species assemblages will be highly altered, and there is a high potential for the disruption of existing interspecific interactions. Although there is a wealth of information on how salinization impacts individual ecosystem components, relatively few studies have addressed the complex and often non-linear feedbacks that determine ecosystem-scale responses or considered how wetland salinization will affect landscape-level processes. Although the salinization of wetlands may be unavoidable in many cases, these systems may also prove to be a fertile testing ground for broader ecological theories including (but not limited to): investigations into alternative stable states and tipping points, trophic cascades, disturbance-recovery processes, and the role of historical events and landscape context in driving community response to disturbance.« less

Geospatial Estimates of Road Salt Usage Across a Gradient of Urbanizing Watersheds in Southern Ontario:Thesis for Masters in Spatial Analysis (MSA)

NASA Astrophysics Data System (ADS)

Giberson, G. K.; Oswald, C.

2015-12-01

In areas affected by snow, chloride (Cl) salts are widely used as a de-icing agent to improve road conditions. While the improvement in road safety is indisputable, there are environmental consequences to local aquatic ecosystems. In many waterways, Cl concentrations have been increasing since the early 1990s, often exceeding national water quality guidelines. To determine the quantity of Cl that is accumulating in urban and urbanizing watersheds, accurate estimates of road salt usage at the watershed-scale are needed. The complex jurisdictional control over road salt application in southern Ontario lends itself to a geospatial approach for calculating Cl inputs to improve the accuracy of watershed-scale Cl mass balance estimates. This study will develop a geospatial protocol for combining information on road salt applications and road network areas to refine watershed-scale Cl inputs, as well as assess spatiotemporal patterns in road salt application across the southern Ontario study region. The overall objective of this project is to use geospatial methods (predominantly ArcGIS) to develop high-accuracy estimates of road salt usage in urbanizing watersheds in southern Ontario. Specifically, the aims will be to map and summarize the types and areas ("lane-lengths") of roadways in each watershed that have road salt applied to them, to determine the most appropriate source(s) of road salt usage data for each watershed, taking into consideration multiple levels of jurisdiction (e.g. municipal, regional, provincial), to calculate and summarize sub-watershed and watershed-scale road salt usage estimates for multiple years, and to analyze intra-watershed spatiotemporal patterns of road salt usage, especially focusing on impervious surfaces. These analyses will recommend areas of concern exacerbated by high-levels of road salt distribution; recommendations around modifying on-the-ground operations will be the next step in helping to correct these issues.

The Corrosion of High Performance Steel in Adverse Environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Desmond C.

The corrosion products that have formed on weathering steel bridges exposed to different weather conditions in the United States have been evaluated. They have been analyzed by spectroscopic techniques to determine the relationship between protective and non-protective rust coatings, and their relationship to the exposure conditions. Bridges constructed recently using High Performance Steel, as well as older bridges built with Type A588B weathering steel, were evaluated for corrosion performance of the rust coatings. In locations where the steel is subjected to regular wet-dry cycling, where the surface is wet for less than about 20% of the time, a protective patinamore » starts to form after a few months exposure, and continues to an adherent, impervious coating after a decade. The protective patina is characterized by the formation of only goethite and lepidocrocite. The goethite makes up about 80% of the rust, and itself consists of a nanophase component, < 15 nm, making up about 70% of the goethite. The nanophase goethite is basically undetected by X-ray diffraction. In the presence of high time-of-wetness, >40%, or infrequent drying cycles (regions close to waterways, fog or having high humidity), the weathering steel forms a rust coating that consists of a large amount of maghemite, and goethite that contains very little of the nanophase component. The rust coating ex-foliates from the steel and is not protective. Under exposure conditions in which chlorides are deposited onto the weathering steel surface (marine or de-icing salt locations), the protective patina also does not form. Instead, the rust coating consists of a large fraction of akaganeite that forms at the expense of the lepidocrocite and nanophase goethite. The bridges exposed to high chloride concentrations, 1.5 wt%, and therefore having no protective patina, have corrosion rates measured to be 6 times larger than expected for weathering steel with the protective patina.« less

Experimental Study on Modification of Concrete with Asphalt Admixture

NASA Astrophysics Data System (ADS)

Bołtryk, Michał; Małaszkiewicz, Dorota; Pawluczuk, Edyta

2017-10-01

Durability of engineering structures made of cement concrete with high compressive strength is a very vital issue, especially when they are exposed to different aggressive environments and dynamic loads. Concrete resistance to weathering actions and chemical attack can be improved by combined chemical and mechanical modification of concrete microstructure. Asphalt admixture in the form of asphalt paste (AP) was used for chemical modification of cement composite microstructure. Concrete structure was formed using special technology of compaction. A stand for vibro-vibropressing with regulated vibrator force and pressing force was developed. The following properties of the modified concrete were tested: compressive strength, water absorption, freeze-thaw resistance, scaling resistance in the presence of de-icing agents, chloride migration, resistance to CO2 and corrosion in aggressive solutions. Corrosion resistance was tested alternately in 1.8% solutions of NH4Cl, MgSO4, (NH2)2CO and CaCl2, which were altered every 7 days; the experiment lasted 9.5 months. Optimum compaction parameters in semi-industrial conditions were determined: ratio between piston stress (Qp ) and external top vibrator force (Po ) in the range 0.4÷-0.5 external top vibrator force 4 kN. High strength concretes with compressive strength fcm = 60÷70 MPa, very low water absorption (<1%) and high resistance to aggressive environments were obtained in this study. AP content was reduced from 10% (previous investigations) to 2-4% of cement mass thanks to the special compaction method. Excellent chloride ion penetration resistance and carbonation resistance of concrete containing AP admixture is due to the asphalt barrier formed in pores of cement hydrates against dioxide and chloride ions. Concrete specimens containing AP 4% c.m. and consolidated by vibro-vibropressing method proved to be practically resistant to highly corrosive environment. Vibro-vibropressing compaction technology of concrete modified with AP can be applied in prefabrication plants to produce elements for road, bridge and hydraulic engineering constructions.

Corrosion initiation and propagation behavior of corrosion resistant concrete reinforcing materials

NASA Astrophysics Data System (ADS)

Hurley, Michael F.

The life of a concrete structure exposed to deicing compounds or seawater is often limited by chloride induced corrosion of the steel reinforcement. In this study, the key material attributes that affect the corrosion initiation and propagation periods were studied. These included material composition, surface condition, ageing time, propagation behavior during active corrosion, morphology of attack, and type of corrosion products generated by each rebar material. The threshold chloride concentrations for solid 316LN stainless steel, 316L stainless steel clad over carbon steel, 2101 LDX, MMFX-2, and carbon steel rebar were investigated using electrochemical techniques in saturated calcium hydroxide solutions. Surface preparation, test method, duration of period exposed to a passivating condition prior to introduction of chloride, and presence of cladding defects all affected the threshold chloride concentration obtained. A model was implemented to predict the extension of time until corrosion initiation would be expected. 8 years was the predicted time to corrosion initiation for carbon steel. However, model results confirmed that use of 316LN may increase the time until onset of corrosion to 100 years or more. To assess the potential benefits afforded by new corrosion resistant rebar alloys from a corrosion resistance standpoint the corrosion propagation behavior and other factors that might affect the risk of corrosion-induced concrete cracking must also be considered. Radial pit growth was found to be ohmically controlled but repassivation occurred more readily at high potentials in the case of 316LN and 2101 stainless steels. The discovery of ohmically controlled propagation enabled transformation of propagation rates from simulated concrete pore solution to less conductive concrete by accounting for resistance changes in the surrounding medium. The corrosion propagation behavior as well as the morphology of attack directly affects the propensity for concrete cracking. Experimental results were used in conjunction with an existing model to predict the time until concrete cracking occurs for new rebar materials. The results suggest that corrosion resistant materials offer a significant extension to the corrosion propagation stage over carbon steel, even in very aggressive conditions because small, localized anodes develop when initiated.

Sulfate transport kinetics and toxicity are modulated by sodium in aquatic insects.

PubMed

Scheibener, Shane; Conley, Justin M; Buchwalter, David

2017-09-01

The salinization of freshwater ecosystems is emerging as a major ecological issue. Several anthropogenic causes of salinization (e.g. surface coal mining, hydro-fracking, road de-icing, irrigation of arid lands, etc.) are associated with biodiversity losses in freshwater ecosystems. Because insects tend to dominate freshwater ecology, it is important that we develop a better understanding of how and why different species respond to salinity matrices dominated by different major ions. This study builds upon previous work demonstrating that major ion toxicity to the mayfly Neocloeon triangulifer was apparently due to the ionic composition of water rather than specific conductance. Synthetic waters with low Ca:Mg ratios and high SO 4 :Na ratios produced toxicity, whereas waters with higher Ca:Mg ratios and lower SO 4 :Na ratios were not toxic to mayflies at comparable conductivities. Here we used a radiotracer approach to show that Mg did not competitively exclude Ca uptake at environmentally realistic ratios in 4 aquatic insect species. We characterized SO 4 uptake kinetics in 5 mayflies and assessed the influence of different ions on SO 4 uptake. Dual label experiments show an inverse relationship between SO 4 and Na transport rates as SO 4 was held constant and Na was increased, suggesting that Na (and not Cl or HCO 3 ) is antagonistic to SO 4 transport. Based on this observation, we tested the hypothesis that increasing Na would protect against SO 4 induced toxicity in a Na-dependent manner. Increasing Na from 0.7 to 10.9mM improved 96-h survivorship associated with 20.8mM SO 4 from 44% to 73% in a concentration dependent manner. However, when Na reached 21.8mM, survivorship decreased to 16%, suggesting that other interactive effects of major ions caused toxicity under those conditions. Thus, the combination of elevated sulfate and low sodium commonly observed in streams affected by mountaintop coal mining has the potential to cause toxicity in sensitive aquatic insects. Overall, it is important that we develop a better understanding of major ion toxicity to effectively mitigate and protect freshwater biodiversity from salinization. Copyright © 2017 Elsevier B.V. All rights reserved.

Modeling salinization and recovery of road salt-impacted lakes in temperate regions based on long-term monitoring of Lake George, New York (USA) and its drainage basin.

PubMed

Sutherland, J W; Norton, S A; Short, J W; Navitsky, C

2018-05-08

Road salt mitigates winter highway icing but accumulates in watershed soils and receiving waters, affecting soil chemistry and physical, biological, and ecological processes. Despite efforts to reduce salt loading in watersheds, accumulated cations and Cl - continue to impact tributaries and lakes, and the recovery process is not well understood. Lake George, New York (USA) is typical of many temperate lakes at risk for elevated Cl - concentrations from winter deicing; the lake salt concentration increased by ~3.4% year -1 since 1980. Here, we evaluated the ionic composition in Finkle Brook, a major watershed draining to Lake George, studied intermittently since 1970 and typical of other salt-impacted Lake George tributaries. Salt loading in the Lake George basin since the 1940s displaced cations from exchange sites in basin soils; these desorbed cations follow a simple ion-exchange model, with lower sodium and higher calcium, magnesium and potassium fluxes in runoff. Reduced salt application in the Finkle Brook watershed during the low-snow winter of 2015-2016 led to a 30-40% decline of Cl - and base cations in the tributary, implying a Cl - soil half-life of 1-2 years. We developed a conceptual model that describes cation behavior in runoff from a watershed that received road salt loading over a long period of time, and then recovery following reduced salt loading. Next, we developed a dynamic model estimating time to steady-state for Cl - in Lake George with road salt loading starting in 1940, calibrating the model with tributary runoff and lake chemistry data from 1970 and 1980, respectively, and forecasting Cl - concentrations in Lake George based on various scenarios of salt loading and soil retention of Cl - . Our Lake George models are readily adaptable to other temperate lakes with drainage basins where road salt is applied during freezing conditions and paved roads cover a portion of the watershed. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of urban stormwater runoff on ground water beneath recharge basins on Long Island, New York

USGS Publications Warehouse

Ku, H.F.; Simmons, D.L.

1986-01-01

Urban stormwater runoff was monitored during 1980-82 to investigate the source, type, quantity, and fate of contaminants routed to the more than 3,000 recharge basins on Long Island and to determine whether this runoff might be a significant source of contamination to the groundwater reservoir. Forty-six storms were monitored at five recharge basins in representative land use areas (strip commercial, shopping-mall parking lot, major highway, low-density residential, and medium-density residential). Runoff:precipitation ratios indicate that all storm runoff is derived from precipitation on impervious surfaces in the drainage area, except during storms of high intensity or long duration, when additional runoff can be derived from precipitation on permeable surfaces. Lead was present in highway runoff in concentrations up to 3300 micrograms/L, and chloride was found in parking lot runoff concentrations up to 1,100 mg/L during winter, when salt is used for deicing. In the five composite stormwater samples and nine groundwater grab samples that were analyzed for 113 EPA-designated ' priority pollutants, ' four constituents were detected in concentrations exceeding New York State guidelines of 50 micrograms/L for an individual organic compound in drinking water: p-chloro-m-cresol (79 micrograms/L); 2 ,4-dimethylphenol (96 micrograms/L); 4-nitrophenol (58 micrograms/L); and methylene chloride (230 micrograms/L in either groundwater or stormwater at the highway basin). One stormwater sample and two groundwater samples exceeded New York State guidelines for total organic compounds in drinking water (100 micrograms/L). The presence of these constituents is attributed to contamination from point sources rather than to the quality of runoff from urban areas. The median number of indicator bacteria in stormwater ranged from 0.1 to 10 billion MPN/100 ml. Fecal coliforms and fecal streptococci increased by 1 to 2 orders of magnitude during the warm season. The use of recharge basins to dispose of storm runoff does not appear to have significant adverse effects on groundwater quality in terms of the chemical and microbiological stormwater constituents studied. (Author 's abstract)

Microbial Degradation of Propylene Glycol - Modelling Approach of a Batch Experiment

NASA Astrophysics Data System (ADS)

Dathe, Annette; Fernandez, Perrine; Bakken, Lars; Bloem, Esther; French, Helen

2016-04-01

De-icing chemicals are applied in large amounts at airports during winter conditions to keep the runways and aircrafts ice-free. At Gardermoen airport, Norway, most of the applied chemicals can be captured, but about 10 to 20 % infiltrate into the soil along the runways and during take-off. While the commonly used propylene glycol (PG) is easily degradable by local microbial communities, its biological oxygen demand is high, anoxic zones can develop and soluble Fe+2 and Mn+2 ions eventually can reach the groundwater. The objectives of the presented study are to quantify the mechanisms, which control the order of reduction processes in an unsaturated sandy soil, and to test whether measured redox potentials can help to determine underlying biogeochemical reactions. To investigate the mechanisms of microbial degradation, the water phase of soil samples from Gardermoen Airport was replaced by deionized water with 10 mMol PG or 10 mMol glutamate and the samples were incubated at 10°C for about two weeks. The gas phase was sampled and analyzed automatically every three hours. Microbial degradation of the substrate (PG or glutamate) was modelled following a Monod kinetics using the FME (Flexible Modelling Environment) package of R (Project for Statistical Computing). The model was calibrated against measurements of O2 depletion and CO2 production. The initial concentrations of O2, CO2 and PG or glutamate are known and microbial yields and stoichiometric constants can be calculated from the measurements. Parameter values for the initial microbial population size, maximum microbial growth rate, the half saturation constant, and microbial degradation and respiration rates were fitted using the FME package. The model accounts for carbon from the substrate (PG or glutamate) incorporated into the biomass. Results are promising, but because of the large number of parameters needed to fit a Monod kinetics it is challenging to accurately model a whole redox sequence. The ultimate goal of implementing PG degrading processes into a soil water transport model is still a challenge, and simpler approaches like a first- and second order kinetic are investigated and compared to the behavior of the Monod kinetic.

Spatial and temporal variability of source contributions to ambient PM10 during winter in Augsburg, Germany using organic and inorganic tracers.

PubMed

Qadir, R M; Schnelle-Kreis, J; Abbaszade, G; Arteaga-Salas, J M; Diemer, J; Zimmermann, R

2014-05-01

Daily PM10 samples were collected during a one-month sampling campaign from February 13 to March 12, 2008 at eight different sampling sites in Augsburg, Southern Germany. Source apportionment was performed to identify the main sources and related contributions by analysis of organic and inorganic tracers. Nine factors were separated comprising: solid fuel combustion, traffic-related emissions, secondary inorganics, and mixed sources. Spatiotemporal variation of the source contributions was evaluated using the Pearson correlation coefficient (r) and coefficient of divergence (COD). All factors (except hopanes and mixed sources) showed moderate to high (0.60.8) correlation coefficients between the eight sites and were distributed heterogeneously. Secondary sulfate and secondary nitrate factors were relatively more uniformly distributed (compared to other factors) with lower medians of COD value (0.47 and 0.56, respectively) and higher correlation values (r=0.97 and 0.85, respectively). The maximum daily average contribution for coal & wood combustion factor was observed at the LfU suburban site (4.0 μg m(-3)); wood combustion factor at the LSW residential site (5.1 μg m(-3)) ; diesel & fuel oil consumption factor at the Bifa suburban and BP urban sites (both 2.5 μg m(-3)); road dust & tram factor at the KP traffic site (16.2 μg m(-3)) and the BP urban site (6.6 μg m(-3)); hopanes factor at the BP urban and Bifa suburban sites (both 0.7 μg m(-3)); and de-icing NaCl factor at the KP traffic site (4.8 μg m(-3)). Secondary sulfate and secondary nitrate factors had approximately similar contributions (6.2 μg m(-3) and 4.3 μg m(-3), respectively) at all sites. Mixed sources factor had the highest daily average contribution to PM10 mass at the KP traffic site (7.0 μg m(-3)). Copyright © 2013 Elsevier Ltd. All rights reserved.

Long-term response of surface water acid neutralizing capacity in a central Appalachian (USA) river basin to declining acid deposition

NASA Astrophysics Data System (ADS)

Kline, Kathleen M.; Eshleman, Keith N.; Garlitz, James E.; U'Ren, Sarah H.

2016-12-01

Long-term changes in acid-base chemistry resulting from declining regional acid deposition were examined using data from repeating synoptic surveys conducted within the 275 km2 Upper Savage River Watershed (USRW) in western Maryland (USA); a randomly-selected set of 40 stream reaches was sampled 36 times between 1999 and 2014 to: (1) repeatedly characterize the acid-base status of the entire river basin; (2) determine whether an extensive network of streams of varying order has shown signs of recovery in acid neutralizing capacity (ANC); and (3) understand the key factors controlling the rate of ANC recovery across the river network. Several non-parametric analyses of trends (i.e., Mann Kendall Trend: MKT tests; and Regional Kendall Trend: RKT) in streamwater acid-base chemistry suggest that USRW has significantly responded to declining acid deposition during the study period; the two most robust, statistically significant trends were decreasing surface water SO42- (∼1.5 μeq L-1 yr-1) and NO3- (∼1 μeq L-1 yr-1) concentrations-consistent with observed downward trends in regional wet S and N deposition. Basin-wide decreasing trends in K+, Mg2+, and Ca2+ were also observed, while Na+ concentrations increased. Significant ANC recovery was observed in 10-20% of USRW stream reaches (depending on the p level used), but the magnitude of the trend relative to natural variability was apparently insufficient to allow detection of a basin-wide ANC trend using the RKT test. Watershed factors, such as forest disturbances and increased application of road deicing salts, appeared to contribute to substantial variability in concentrations of NO3- and Na+ in streams across the basin, but these factors did not affect our overall interpretation of the results as a systematic recovery of USRW from regional acidification. Methodologically, RKT appears to be a robust method for identifying basin-wide trends using synoptic data, but MKT results for individual systems should be examined closely (e.g., to identify trends for specific subpopulations).

The Boulby Geoscience Project Underground Research Laboratory: Initial Results of a Rock Mechanics Laboratory Testing Programme

NASA Astrophysics Data System (ADS)

Brain, M. J.; Petley, D. N.; Rosser, N.; Lim, M.; Sapsford, M.; Barlow, J.; Norman, E.; Williams, A.; Pybus, D.

2009-12-01

The Boulby Mine, which is situated on the northeast coast of England, is a major source of potash, primarily for use as a fertiliser, with a secondary product of rock salt (halite), used in highway deicing. The deposits are part of the Zechstein formation and are found at depths of between c.1100 and 1135 m below sea level. The evaporite sequence also contains a range of further lithologies, including anhydrite, dolomite and a mixed evaporate deposit. From a scientific perspective the dry, uncontaminated nature of the deposits, the range of lithologies present and the high stress conditions at the mine provide a unique opportunity to observe rock deformation in situ in varying geological and stress environments. To this end the Boulby Geoscience Project was established to examine the feasibility of developing an underground research laboratory at the mine. Information regarding the mechanical properties of the strata at the Boulby Mine is required to develop our understanding of the strength and deformation behaviour of the rock over differing timescales in response to variations in the magnitude and duration of applied stresses. As such data are currently limited, we have developed a laboratory testing programme that examines the behaviour of the deposits during the application of differential compressive stresses. We present the initial results of this testing programme here. Experiments have been carried out using a high pressure Virtual Infinite Strain (VIS) triaxial apparatus (250 kN maximum axial load; 64 MPa maximum cell pressure) manufactured by GDS Instruments. Conventional compression tests under uniaxial and triaxial conditions have been undertaken to determine the effects of axial stress application rate, axial strain rate and confining pressure on behaviour and failure mechanisms. The experimental programme also includes advanced testing into time-dependent creep behaviour under constant deviatoric stress; the effects of variations in temperature and stress path loading on peak shear strength and deformation behaviour; and the effects of low frequency cyclic loading on evolution of material properties. We compare the results of the testing programme with similar published data on evaporite rocks and existing models of material deformation and briefly discuss the implications for the design of sub-surface excavations.

Investigation of residual stresses in shape memory alloy (SMA) composites

NASA Astrophysics Data System (ADS)

Berman, Justin Bradley

Shape memory alloy (SMA) composites are a class of smart materials in which SMA actuators are embedded in a host matrix. The shape memory effect allows for stress induced phase transformations and large recoverable strains that make SMA composites promising candidates for structural shape/vibration control, impact absorption, aircraft deicing or in-flight airfoil shape control systems. However, the difference in thermal expansion between the SMA and the host material leads to residual stresses during processing. In addition, the SMA transformation from martensite to austenite, or the reverse, also generate stresses. These stresses acting in combination can lead to SMA/polymer interfacial debonding or microcracking of the host matrix. The present work was undertaken to study the behavior of nitinol shape memory alloys embedded in epoxy and glass/epoxy matrices and to investigate the development of residual stresses during their manufacture and actuation. A three-phase concentric cylinder micromechanics model and an SMA composite thermoelastic beam theory were developed to analyze the micromechanical and structural-level thermal and transformational stresses for nitinol composites induced by nitinol wires embedded in a host matrix. A series of warpage experiments were conducted on nitinol composite beams during heating cycles to provide experimental validation of model predictions and to assess their thermoelastic structural behavior under non-mechanical loading. Micromechanical model results indicate that excessive residual hoop stresses in nitino/graphite/epoxy composites leads to radial cracking around the embedded nitinol wires. Based on modeling results, the most important factor in reducing residual stresses (and thereby preventing radial cracking) is increasing the level of recovery strain for the nitinol wire. The SMA composite beam model agrees well with experimental data captured for the nitinol/epoxy beam series. Warpage experiments on nitinol/glass/epoxy beams showed a large increase in the effective austenitic start temperature (As) of 9.3°C. The elevation of the effective As together with other observations of warpage development indicates that plastic flow may have occurred in nitinol wires when embedded in glass/epoxy. These observations reinforce the need to train nitinol wires at modest recovery levels when embedding in relatively stiff materials.

Development of an analytical method to predict helicopter main rotor performance in icing conditions

NASA Technical Reports Server (NTRS)

Britton, Randall K.

1992-01-01

Historically, certification of a helicopter for flight into known icing conditions was a problem. This is because of the current emphasis on flight testing for verification of system performance. Flight testing in icing conditions is difficult because, in addition to being dangerous and expensive, many times conditions which are sought after cannot be readily found in nature. The problem is compounded for helicopters because of their small range in comparison to many fixed wing aircraft. Thus, helicopters are forced to wait for conditions to occur in a certain region rather than seeking them out. These and other drawbacks to flight testing prompted extreme interest in developing validated alternatives to flight testing. One such alternative is theoretical prediction. It is desirable to have the ability to predict how a helicopter will perform when subjected to icing conditions. Herein, calculations are restricted to the main rotor, and are illustrated. The computational tool used to obtain performance is the lifting line analysis of B65. B65 incorporates experimental data into data banks in order to determine the section lift, drag, and moment characteristics of various airfoils at different Mach numbers and angles of attack. The local flow angle is calculated at user specified radial locations. This flow angle, along with the local Mach number is then cross referenced with the airfoil tables to obtain the local section characteristics. The local characteristics are then integrated together to obtain the entire rotor attributes. Once the clean performance is known, characterization of the type and shape of ice which accretes on the rotor blades is obtained using the analysis of LEWICE. The Interactive Boundary Layer (IBL) method then calculates the 2-D characteristics of the iced airfoil for input into the airfoil data bank of B65. Calculations are restricted to natural ice shedding and it is assumed that no de-icing takes place. Once the new lift, drag, and moment characteristics are known for the entire blade radius, this information is fed into B65, where the iced performance is then calculated.

Loads and yields of deicing compounds and total phosphorus in the Cambridge drinking-water source area, Massachusetts, water years 2009–15

USGS Publications Warehouse

Smith, Kirk P.

2017-09-12

The source water area for the drinking-water supply of the city of Cambridge, Massachusetts, encompasses major transportation corridors, as well as large areas of light industrial, commercial, and residential land use. Because of the large amount of roadway in the drinking-water source area, the Cambridge water supply is affected by the usage of deicing compounds and by other constituents that are flushed from such impervious areas. The U.S. Geological Survey (USGS) has monitored surface-water quality in the Cambridge Reservoir and Stony Brook Reservoir Basins, which compose the drinking-water source area, since 1997 (water year 1998) through continuous monitoring and the collection of stream-flow samples.In a study conducted by the USGS, in cooperation with the City of Cambridge Water Department, concentrations and loads of calcium (Ca), chloride (Cl), magnesium (Mg), sodium (Na), and sulfate (SO4) were estimated from continuous records of specific conductance and streamflow for streams and tributaries at 10 continuous water-quality monitoring stations. These data were used to characterize current (2015) water-quality conditions, estimate loads and yields, and describe trends in Cl and Na in the tributaries and main-stem streams in the Cambridge Reservoir and Stony Brook Reservoir Basins. These data also were used to describe how stream-water quality is related to various basin characteristics and provide information to guide future management of the drinking-water source area.Water samples from 2009–15 were analyzed for physical properties and concentrations of Ca, Cl, Mg, Na, potassium (K), SO4, and total phosphorus (TP). Values of physical properties and constituent concentrations varied widely, particularly in composite samples of stormflow from tributaries that have high percentages of constructed impervious areas. Median concentrations of Ca, Cl, Mg, Na, and K in samples collected from the tributaries in the Cambridge Reservoir Basin (27.2, 273, 4.7, 154.5, and 2.8 milligrams per liter (mg/L), respectively) were higher than those for the Stony Brook Reservoir Basin (22.2, 128, 4.3, 77.1, and 2.5, respectively). Differences between tributary samples for concentrations of Cl and Na were related to the percentage of developed land and constructed impervious area in the drinking-water source area. Median concentrations of SO4 in samples collected from the tributaries in the Cambridge Reservoir Basin (10.7 mg/L) were lower than those for the Stony Brook Reservoir Basin (18.0 mg/L).Concentrations of dissolved Cl and Na in samples and those concentrations estimated from continuous records of specific conductance (particularly during base flow) often were greater than the U.S. Environmental Protection Agency (EPA) secondary drinking-water standard for Cl (250 mg/L), the chronic aquatic-life guideline for Cl (230 mg/L), and the Massachusetts Department of Environmental Protection drinking-water guideline for Na (20 mg/L). Concentrations of TP (range from 0.008 to 0.69 mg/L in all subbasins) in tributary samples did not differ substantially between the Cambridge Reservoir and Stony Brook Reservoir Basins. About one-half of the concentrations of TP in samples collected during water years 2013–15 exceeded the EPA proposed reference concentration of 0.024 mg/L.For most tributaries, about 70 percent of the annual loads of Ca, Cl, Mg, Na, and SO4 were associated with base flow. Concentrations of major ions were negatively correlated with streamflow, indicating that these constituents were diluted during stormflow and tend to increase during the summer when streamflow is low. In contrast, between 57 and 92 percent of the annual load for TP was transported during stormflows.Mean annual yields of Ca, Cl, Mg, Na, and SO4 in the drinking-water source area were 13, 75, 2.6, 40, and 6.9 metric tons per square kilometer, respectively, for water years 2009–15. The mean annual yield of TP in the drinking-water source area for water years 2013–15 was 0.012 metric tons per square kilometer. Yields for major ions and TP were highest in tributary subbasins adjacent to Interstate 95.Temporal trends in mean annual concentrations for Cl and Na were not significant for water years 1998‒2015 (period of record by the USGS) for the outlet of the Cambridge Reservoir and for the main stem of Stony Brook downstream from the reservoir. Median values of base-flow concentrations of TP at three stations were higher for samples collected during base-flow conditions during water years 2005–7 than for samples collected during water years 2013–15. However, the results were not significant for statistical tests between concentrations in samples collected during storms for the same periods, indicating that the quality of stormwater remains similar.

Bioclogging Effects Relevant to In-Situ Bioremediation of Organic Contaminants

NASA Astrophysics Data System (ADS)

Bielefeldt, A. R.; Illangasekare, T.

2002-05-01

This presentation will summarize 5 years of laboratory experiments investigating the effects of biodegradation of organic contaminants on the hydrodynamic properties of saturated sand due to biomass accumulation. The contaminants studied included naphthalene, decane, diesel fuel, propylene glycol, and aircraft de-icing fluid (ADF). Most of the experiments were conducted in columns (~6 cm dia x 15 cm L). A wide range of environmental conditions were simulated including low to high organic loading (1.2 to 38,000 mg C/kg dry sand/d), various nutrient concentrations (C:N 3:1 to 5424:1), seepage velocity (0.5-11 m/d), and sand size (average diameter 0.19, 0.32, 0.49 mm). Changes in the hydraulic conductivity and dispersivity of the media over time and the biomass distribution in the sand at the end of the experiments were measured. In general, the hydraulic conductivity in the columns declined over time until a steady-state minimum was reached when the new biogrowth was balanced by endogenous decay and shear stress losses from the system. The minimum conductivity was generally 2 to 4 orders of magnitude below that of the clean sand. Dispersivity was evaluated using bromide tracer tests and monitoring the break-through curves. Dispersivity after biomass growth was always higher than that of the clean sand (up to 10x), but trends over time did not always consistently increase. Under selected conditions the dispersivity initially increased and then decreased, although never achieving a level below that of the clean sand. Final biomass concentrations in the sand at steady state ranged from 0.1 to 10 mg dry weight/g dry sand. In some experiments the biomass was evenly distributed through the sand while in others significantly more biomass was present at the column inlet. Some experiments were also conducted in larger 2-D tanks (122 cm L x 46 cm H x 6 cm W) which allowed the groundwater flow to route around local areas of bioclogging as would be likely to occur in subsurface environments. The implications of ignoring bioclogging effects of the magnitude measured in the experimental systems when predicting contaminant plumes in the subsurface will be illustrated using simple models that incorporate biokinetics and hydrodynamic effects. The models will show the importance of including bioclogging effects when designing enhanced in-situ bioremediation systems.

Instrumentation and monitoring of the nextgen road infrastructure: Some results and perspectives from the R5G project

NASA Astrophysics Data System (ADS)

Hautière, Nicolas; Bourquin, Frédéric

2017-04-01

Through the centuries, the roads - which today constitute in France a huge transport network of 1 millions kilometers length - have always been able to cope with society needs and challenges. As a consequence, the next generation road infrastructure will have to take into account at least three societal transitions: ecological, energetic and digital. The goal of the 5th generation road project (R5G©) [1], led by Ifsttar in France, aligned with the Forever Open program [2], is to design and build demonstrators of such future road infrastructures. The goal of this presentation is to present different results related to the greening of road materials [3], the design of energy-positive roads [4, 5], the test of roads that self-diagnose [6], the design of roads adapted for connected [7], autonomous [8] and electrified vehicles [9], etc. In terms of perspectives, we will demonstrate that the road infrastructures will soon become a complex system: On one side road users will benefit from new services, on the other side such massively connected and instrumented infrastructures will potentially become an opportune sensor for knowledge development in geoscience, such as air quality, visibility and fog monitoring. References: [1] R5G project. r5g.ifsttar.fr [2] Forever Open Road project. www.foreveropenroad.eu [3] Biorepavation project. www.infravation.net/projects/BIOREPAVATION [4] N. Le Touz, J. Dumoulin. Numerical study of the thermal behavior of a new deicing road structure design with energy harvesting capabilities. EGU General Assembly 2015, Apr 2015, Vienne, Austria. [5] S. Asfour, F. Bernardin, E. Toussaint, J.-M. Piau. Hydrothermal modeling of porous pavement for its surface de-freezing. Applied Thermal Engineering. Volume 107, 25 August 2016, Pages 493-500 [6] LGV BPL Instrumentation. http://railenium.eu/wp-content/uploads/2016/08/INSTRUMENTATION-BPL-FR.pdf [7] SCOOP@F project. https://ec.europa.eu/inea/en/connecting-europe-facility/cef-transport/projects-by-country/multi-country/2014-eu-ta-0669-s [8] J. Ehrlich, D. Gruyer, O. Orfila, N. Hautière. Autonomous vehicle : The concept of high quality of service highway. FISITA World congress, Busan, Korea, 2016. [9] FABRIC project. www.fabric-project.eu

Chemistry in the Venus clouds: Sulfuric acid reactions and freezing behavior of aqueous liquid droplets

NASA Astrophysics Data System (ADS)

Delitsky, M. L.; Baines, K. H.

2015-11-01

Venus has a thick cloud deck at 40-70 km altitude consisting of liquid droplets and solid particles surrounded by atmospheric gases. The liquid droplets are highly concentrated aqueous solutions of sulfuric acid ranging in concentration from 70-99 wt%. Weight percent drops off with altitude (Imamura and Hashimoto 2001). There will be uptake of atmospheric gases into the droplet solutions and the ratios of gas-phase to liquid-phase species will depend on the Henry’s Law constant for those solutions. Reactions of sulfuric acid with these gases will form products with differing solubilities. For example, uptake of HCl by H2SO4/H2O droplets yields chlorosulfonic acid, ClSO3H (Robinson et al 1998) in solution. This may eventually decompose to thionyl- or sulfuryl chlorides, which have UV absorbances. HF will also uptake, creating fluorosulfonic acid, FSO3H, which has a greater solubility than the chloro- acid. As uptake continues, there will be many dissolved species in the cloudwaters. Baines and Delitsky (2013) showed that uptake will have a maximum at ~62 km and this is very close to the reported altitude for the mystery UV absorber in the Venus atmosphere. In addition, at very strong concentrations in lower altitude clouds, sulfuric acid will form hydrates such as H2SO4.H2O and H2SO4.4H2O which will have very different freezing behavior than sulfuric acid, with much higher freezing temperatures (Carslaw et al, 1997). Using temperature data from Venus Express from Tellmann et al (2009), and changes in H2SO4 concentrations as a function of altitude (James et al 1997), we calculate that freezing out of sulfuric acid hydrates can be significant down to as low as 56 km altitude. As a result, balloons, aircraft or other probes in the Venus atmosphere may be limited to flying below certain altitudes. Any craft flying at altitudes above ~55 km may suffer icing on the wings, propellers, balloons and instruments which could cause possible detrimental effects (thermal changes, reduced buoyancy, effects on control surfaces, plugging of sample inlets, etc.). Therefore, de-icing equipment should be considered when designing aircraft expected to fly at high altitudes in the Venus clouds.

Spinoff 2001: Special Millennium Feature

NASA Technical Reports Server (NTRS)

2001-01-01

For the past 43 years, NASA has devoted its facilities, labor force, and expertise to sharing the abundance of technology developments used for its missions with the nation's industries. These countless technologies have not only successfully contributed to the growth of the U.S. economy, but also to the quality of life on Earth. For the past 25 years, NASA's Spinoff publication has brought attention to thousands of technologies, products, and services that were developed as a direct result of commercial partnerships between NASA and the private business sector. Many of these exciting technologies included advances in ceramics, computer technology, fiber optics, and remote sensing. New and ongoing research at the NASA field centers covers a full spectrum of technologies that will provide numerous advantages for the future, many of which have made significant strides in the commercial market. The NASA Commercial Technology Network plays a large role in transferring this progress. By applying NASA technologies such as data communication, aircraft de-icing technologies, and innovative materials to everyday functions, American consumers and the national economy benefit. Moving forward into the new millennium, these new technologies will further advance our country's position as the world leader in scientific and technical innovation. These cutting-edge innovations represent the investment of the U.S. citizen in the Space Program. Some of these technologies are highlighted in Spinoff 2001, an example of NASA's commitment to technology transfer and commercialization assistance. This year's issue spotlights the commercial technology efforts of NASA's John F. Kennedy Space Center. Kennedy's extensive network of commercial technology opportunities has enabled them to become a leader in technology transfer outreach. This kind of leadership is exemplified through Kennedy's recent partnership with the State of Florida, working toward the development of the Space Experiment Research and Processing Laboratory. The new laboratory is the first step toward the development of a proposed 400-acre Space Commerce Park, located at Kennedy Space Center. Spinoff, once again, successfully showcases the variety of commercial successes and benefits resulting from the transfer of NASA technology to private industry. It is with great pride and pleasure that we present Spinoff 2001 with a Special Millennium Feature. With help from U.S. industry and commercial technology programs, NASA will continue to assist in the presentation of innovative new products to our nation.

Effects of Urbanization on Stream Water Quality in the City of Atlanta, Georgia, USA

NASA Astrophysics Data System (ADS)

Peters, N. E.

2009-05-01

A long-term stream water-quality monitoring network was established in the City of Atlanta (COA) during 2003 to assess baseline water-quality conditions and the effects of urbanization on stream water quality. Routine hydrologically-based manual stream sampling, including several concurrent manual point and equal width increment sampling, was conducted approximately 12 times per year at 21 stations, with drainage areas ranging from 3.7 to 232 km2. Eleven of the stations are real-time (RT) water-quality stations having continuous measures of stream stage/discharge, pH, dissolved oxygen, specific conductance, water temperature, and turbidity, and automatic samplers for stormwater collection. Samples were analyzed for field parameters, and a broad suite of water-quality and sediment-related constituents. This paper summarizes an evaluation of field parameters and concentrations of major ions, minor and trace metals, nutrient species (nitrogen and phosphorus), and coliform bacteria among stations and with respect to watershed characteristics and plausible sources from 2003 through September 2007. The concentrations of most constituents in the COA streams are statistically higher than those of two nearby reference streams. Concentrations are statistically different among stations for several constituents, despite high variability both within and among stations. The combination of routine manual sampling, automatic sampling during stormflows, and real-time water-quality monitoring provided sufficient information about the variability of urban stream water quality to develop hypotheses for causes of water-quality differences among COA streams. Fecal coliform bacteria concentrations of most individual samples at each station exceeded Georgia's water-quality standard for any water-usage class. High chloride concentrations occur at three stations and are hypothesized to be associated with discharges of chlorinated combined sewer overflows, drainage of swimming pool(s), and dissolution and transport during rainstorms of CaCl2, a deicing salt applied to roads during winter storms. Water quality of one stream was highly affected by the dissolution and transport of ammonium alum [NH4Al(SO4)2] from an alum manufacturing plant in the watershed; streamwater has low pH (<5), low alkalinity and high concentrations of minor and trace metals. Several trace metals (Cu, Pb and Zn) exceed acute and chronic water-quality standards and the high concentrations are attributed to washoff from impervious surfaces.

Multifactorial biogeochemical monitoring of linden alley in Moscow

NASA Astrophysics Data System (ADS)

Ermakov, Vadim; Khushvakhtova, Sabsbakhor; Tyutikov, Sergey; Danilova, Valentina; Roca, Núria; Bech, Jaume

2015-04-01

The ecological and biogeochemical assessment of the linden alley within the Kosygin Street was conducted by means of an integrated comparative study of soils, their chemical composition and morphological parameters of leaf linden. For this purpose 5 points were tested within the linden alley and 5 other points outside the highway. In soils, water extract of soil, leaf linden the content of Cu, Pb, Mn, Fe, Cd, Zn, As, Ni, Co Mo, Cr and Se were determined by AAS and spectrofluorimetric method [1]. Macrocomponents (Ca, Mg, K, Na, P, sulphates, chlorides), pH and total mineralization of water soil extract were measured by generally accepted methods. Thio-containing compounds in the leaves were determined by HPLC-NAM spectrofluorometry [2]. On level content of trace elements the soils of "contaminated" points different from background more high concentrations of lead, manganese, iron, selenium, strontium and low level of zinc. Leaf of linden from contaminated sites characterized by an increase of lead, copper, iron, zinc, arsenic, chromium, and a sharp decrease in the level of manganese and strontium. Analysis of the aqueous extracts of the soil showed a slight decrease in the pH value in the "control" points and lower content of calcium, magnesium, potassium, sodium and total mineralization of the water soil extract. The phytochelatins test in the leaves of linden was weakly effective and the degree of asymmetry of leaf lamina too. The most differences between the variants were marked by the degree of pathology leaves (chlorosis and necrosis) and the content of pigments (chlorophyll and carotene). The data obtained reflect the impact of the application of de-icing salts and automobile emissions. References 1. Ermakov V.V., Danilova V.N., Khyshvakhtova S.D. Application of HPLC-NAM spectrofluorimtry to determination of sulfur-containing compounds in the environmental objects// Science of the biosphere: Innovation. Moscow State University by M.V. Lomonosov, 2014. P. 10-12. 2. Ermakov V.V., Tyutikov S.F., Khushvakhtova S.D., Danilova V.N., Boev V.N., Barabanschikova R.N., Chudinova E.A. Peculiarities of quantitative determination of selenium in biological materials// Bulletin of the Tyumen State University Press, 2010, 3, 206-214. Supported by the Russian Foundation for Basic Research, grant number 15-05-00279a

Benzotriazoles, alkylphenols and bisphenol A in municipal wastewaters and in the Glatt River, Switzerland.

PubMed

Voutsa, Dimitra; Hartmann, Paul; Schaffner, Christian; Giger, Walter

2006-09-01

Many organic micropollutants occur at trace concentrations in municipal wastewater effluents and in the aquatic environment. Some of these xenobiotic chemicals can be considered as 'emerging' contaminants and some are suspect to have endocrine disrupting effects. Among the latter are nonylphenol (NP), octylphenol (OP) and bisphenol A (BPA), which deserve special attention due to their ubiquitous occurrence in the aquatic environment. The complexing agents benzotriazole (BT) and tolyltriazole (TT) are applied as anticorrosive agents (e.g. in cooling and hydraulic fluids, in antifreezing fluids, in aircraft deicing fluids, in dish washing liquids for silver protection), as antifogging agents and as intermediates for the synthesis of various chemicals. The environmental occurrence of NP and OP is caused by the fact that they are intermediate products (metabolites) in the biodegradation of alkylphenol polyethoxylate surfactants. BPA is globally used for the production of polycarbonate and epoxy resins. BT, TT, NP, OP and BPA were quantitatively determined in municipal wastewater effluents in Switzerland and in the Glatt River. The analytes were enriched by solid-phase enrichment. BT and TT were determined underivatized by electrospray LC/tandem MS. Reversed-phase LC was performed on octylsilica columns with isocratic water/methanol elution. Multiple reaction monitoring of the positive ions provided selective and sensitive detection for reliable quantifications. NP, OP and BPA were determined by GC/MS after derivatization with N-methyl-N-(trimethylsilyl)-trifluoroacetamide. BT and TT concentrations in primary and secondary effluents of municipal wastewater treatment plants varied from below 10 to 100 microg/L. The ranges of the concentrations in the Glatt River in ng/L were 636-3,690 for BT, 122-628 for TT, 68-326 for NP, 6-22 for OP and 9-76 for BPA. The corresponding mass flows in g/d were 93-1,870 for BT, 18-360 for TT, 24-183 for NP, 1-16 for OP and 2-72 for BPA. The concentrations and mass flows of NP in the River Glatt were drastically lower than the analogous values found 15 years ago. Thus, a substantially decreased environmental exposure can be observed due to the reduction of the use of alkyphenol polyethoxylate surfactants in Switzerland. The current concentrations of NP, OP and BPA are within the ranges reported for weakly impacted surface waters. The investigated contaminants occur at quantitatively measurable but varying concentrations in municipal wastewaters and in the Glatt River reflecting their ubiquitous input into wastewaters and their different behaviour during biological wastewater treatment.

The application of A.C. impedance spectroscopy on the durability of hydrated cement paste subjected to various environmental conditions

NASA Astrophysics Data System (ADS)

Perron, Stacey

Harsh Canadian winters cause many problems in reinforced concrete structures due to damaging freezing-thawing cycles which is exacerbated by the heavy use of de-icing salts on roadways. Evaluation of concrete durability with current ASTM methods may give unreliable results and are destructive to the structure. A relatively new and novel approach to evaluating the durability of concrete uses A. C. Impedance Spectroscopy (ACIS). Hydrated cement paste (hcp), mortar, brick and vycor glass were evaluated using ACIS during drying-rewetting and freezing-thawing cycles. Thermal mechanical analysis (TMA), and differential scanning calorimetry (DSC) tests were also conducted and used as references. Results indicate that ACIS can be used to successfully evaluate the pore structure of hcp. The results from the drying-rewetting cycles are consistent with the pore coarsening theory. ACIS revealed pore structure changes consistent with the mechanical strains and pore solution chemistry. Increased pore continuity with each drying-rewetting cycle was indicated by a reduction in sample resistance. Unique tests were conducted on hydrated cement paste, mortar, brick and vycor glass that measured the ACIS and mechanical strains simultaneously while undergoing temperature changes. The temperature was lowered from 5°C to -80°C and then raised to +20°C. The ACIS results indicate that durability of the material can be assessed using the parameters R, material resistance, and phi, indicative of the frequency dispersion angle. The resistance on freezing values correlates with the amount of pore water freezing. The phi values on freezing are representative of the pore size distribution of the test sample. Resistance and phi data from freezing-thawing tests can be analyzed to assess durability of the sample. A material that is durable to freezing-thawing cycles can be described as having a high resistance at room temperature, a low freezing resistance and small changes in phi. Results were consistent among all the materials tested. Freezing-thawing tests were also conducted on specimens resaturated with salt solutions (5%, 10%, 15%). The results of these tests indicated a lower incipient freezing temperature, increase in pore blockage temperatures, and increased mobility of the pore water during freezing (increase in the change to phi). A series of test were conducted to evaluate the electrode polarization effects associated with the permittivity values at low frequencies. Teflon sheets were used to minimize the electrode polarization effects. It is shown that electrode polarization effects dominate over bulk polarization effects. Effects vary with the porosity of the material.

Effects of an Alpine Ski Resort on Hydrology and Water Quality in the Northeastern U.S.: Preliminary Findings from a Field Study

NASA Astrophysics Data System (ADS)

Wemple, B.; Shanley, J.; Denner, J.

2002-12-01

High elevation, forested watersheds are particularly vulnerable to stresses from development. Steep slopes and thin soils rapidly transmit water, nutrients and sediment when disturbed by logging, road construction or other activities associated with development. The effects of forest harvesting practices on streamflow and water quality in high-elevation, forested watersheds have been well studied and provide relevant information about the susceptibility of these ecosystems to anthropogenic disturbance. Few studies have directly addressed the hydrologic or water quality effects of ski resort development on mountain streams, and these studies draw almost entirely from western U.S. examples. Ski resorts in the eastern U.S. face particular development pressures. Transient and unpredictable snow conditions generate extensive need for snowmaking. Competitive economic pressure has motivated plans for slope-side village development and summer recreation facilities at many eastern U.S. ski resorts. Here, we report preliminary findings of a recently initiated paired-watershed study to examine the effects of alpine ski area development on water quantity and quality. Our study area is located on the eastern slope of Mt. Mansfield, Vermont, and includes the basins of Ranch Brook (9.6 sq km) and West Branch (11.7 sq km). Ranch Brook is undeveloped, except for a network of cross-country ski trails and unsurfaced access roads, and serves as our control watershed. West Branch encompasses nearly an entire major ski resort, with an extensive network of alpine ski lifts and trails, day lodges, snowmaking facilities, and vacation homes. A major expansion of resort facilities and ski trails has recently received state approval. Our preliminary analysis indicates distinct differences in runoff and water quality between the two basins. Differences in basin hydrographs suggest that ski trails alter the timing and magnitude of runoff, particularly during spring snowmelt. Elevated concentrations of total suspended solids in West Branch streamwater suggest that exposed surfaces (trails, parking lots) may be important sources of sediment in the ski resort basin. Streamwater chemistry at West Branch also suggests contamination by deicing salts. Variability in summer low flows between the two basins indicates unexplained differences in precipitation capture or groundwater loss in the basins and must be resolved in future analysis. These findings provide important baseline information for ski area management in the eastern U.S., where field studies have been sparse. Our future plans include hydrologic modeling to assess the effects of current development and various future development scenarios on streamflow and water quality.

Selection for salt tolerance in tidal freshwater swamp species: Advances using baldcypress as a model for restoration: Chapter 14

USGS Publications Warehouse

Krauss, Ken W.; Chambers, Jim L.; Creech, David L.

2007-01-01

Worldwide, the intrusion of salinity into irrigated and natural landscapes has major economic and cultural impacts and has resulted in large reductions in crop yields (Epstein et al. 1980; Flowers 2003). Losses have prompted wide-scale programs to improve the salt tolerance of many agronomic species or to identify crop species that can tolerate lands affected by low levels of salinity. Few historic research efforts have considered forest tree species in the United States, especially in nonurban areas. Newer programs have focused on identifying salt tolerance in forest tree species but have mainly limited these efforts to compiling lists of salt tolerant species to be used in afforestation projects (Gogate et al. 1984; Shrivastava et al. 1988; Beckmann 1991; Bell 1999). Gogate et al. (1984), for instance, listed 26 potential species from Australia with silvicultural application to salt affected lands in India. More comprehensive efforts have considered species lists along with specific site requirements (Bell 1999); species tolerant to saline irrigation waters on dry land, for example, will not often be tolerant of salinity increases in wetland settings. Similar ideas have spawned field trials of native and nonnative tree species in India, Pakistan, Thailand, Australia, and the United States (Thomson 1988; Beckmann 1991; Krauss et al. 2000; Conner and Ozalp 2002; Marcar and Crawford 2004; Conner and Inabinette 2005). Concerted attempts at salt tolerance improvement of forest tree species have been limited, owing in part to the diversity of regional issues that such programs must consider. Whereas food, fodder, and pulp yield may be the major improvement goal on salt affected lands in India (Mathur and Sharma 1984), identifying trees that can survive deicing salts (Townsend 1989), oil and gas brine discharges (Auchmoody and Walters 1988), or sea-level rise induced salinity changes (Pezeshki et al. 1987, 1990) are of greater interest to larger industrial nations. Nevertheless, salt tolerance research on a range of tree species has converged on one very important finding; among the mechanisms proposed for salt tolerance in nonhalophytes (Greenway and Munns 1980; Munns and Termaat 1986; Cheeseman 1988), ion exclusion from cellular processes, especially exclusion of Cl- , ranks high (Townsend 1989). Identifying the principal mechanism and location of ion exclusion and determining the range of additive genetic variation available among physiological, morphological, and growth attributes for individual species have been the major elements of salt tolerance improvement programs for trees (Allen et al. 1994a).

Assessment of Continuous Resistivity Profiling for the Characterization of Paved Roads

NASA Astrophysics Data System (ADS)

Chouteau, M.; Vallieres, S.; Miralles, M.

2004-05-01

We have assessed the continuous resistivity profiling method using towed arrays as a diagnostic NDT method for the evaluation of pavements. Whether the pavement consists of a sequence of asphalt, concrete slab and subgrade layer (rigid pavement) or a layer of asphalt overlying a subgrade and grade base layers (flexible pavement) defects within those different layers can cause pavement deterioration that must be identified. We first examine the response of the method to the various problems using numerical modeling. It is shown that with an optimally designed system the method allows the determination of the thickness and the location of cracks in the asphalt cover. It is also sensitive to the presence of cracks, internal defects and chloride ions (de-icing salt) within the concrete slab below. For reinforced concrete it is possible to estimate the concrete resistivity related directly to its composition (quality) and the thickness of the top coating over the level of rebars. A low resistivity of concrete will usually be diagnostic of advanced stage of rebar corrosion and delamination could occur. However it is shown that the rebars cause current channeling and the depth of investigation is limited then to the depth of the first row of rebars. Finally heterogeneities within the foundation reflecting subsidence, bad drainage, frost-defrost cycles or cavities can be mapped. The optimal design is based on a system with 10 to 20 receiver dipoles and one transmitter dipole (first or last of the array) with a dipole length typically of 10 cm that can be used in equatorial or in-line mode. Static resistivity measurements have been carried out at the laboratory scale over concrete slabs built to verify results obtained from the numerical modeling. Observed data fit very well the modeled data and validate the overall conclusions. Tests have been performed in December 2003 in some selected streets (6 visited, 3 re-visited) of Montreal using a CORIM system (Iris Instruments, France), a capacitively-coupled resistivity towed equatorial array that continuously record data collected with six receiver dipoles and one transmitter dipole. Typical acquisition sampling and velocity were 0,20-0,50 m and 1 to 2 km/h respectively. Although the system is not optimally designed for the applications described above it provides useful diagnostic information about the state of deterioration of pavement. Data have been imaged using 2D resistivity inversion. In general it shows a high resistivity for the shallow depth related to the asphalt layer and a decreasing resistivity with depth related to the concrete slab first and the granular foundation below. Lateral variations appear to be correlated with degradation of the concrete slab.

Examination of Single- and Multi-Channel GPR Bridge Deck Condition Assessment Methods with Comparison to Complementary NDE Results

NASA Astrophysics Data System (ADS)

Romero, Francisco A.; Manacorda, Guido; Simi, Alessandro; Gucunski, Nenad; Parvardeh, Hooman

2013-04-01

A sixteen-channel GPR system which houses both longitudinally- and transversely-polarized, 2.0 GHz antenna elements within a single housing was compared with a single-channel GPR system that was separately using both 1.5GHz and 2.6GHz antennas oriented in the transverse polarization, for the purpose of determining effectiveness of bridge deck condition assessment. The multi-channel system has obvious benefits which include closely-spaced GPR antennas (channels) that provide better lateral resolution, as well as combined data sets from co-linear antennas oriented in both the transverse and longitudinal polarizations, which has benefits for imaging within the deck's internal structure. However, the primary objective was to determine whether the multi-channel system would perform in a similar manner to proven single-channel GPR technology during an attenuation-based GPR condition assessment on an older, partially deteriorated deck in northwestern New Jersey that is annually exposed to freeze-thaw conditions as well as de-icing salts. These assessments were made by focusing on identifying the strongest reflections from the upper mat of transversely-oriented rebars within the deck and comparing reflection strength, or conversely, attenuation of the GPR signal, from each of the 'picked' GPR rebar responses. Coordinates for each of the GPR picks, along with amplitude or attenuation measurements, were gridded and contour-plotted for the purpose of identifying areas identified as either relatively deteriorated or sound. Initially, results were compared for data with no applied correction that takes into account GPR signal attenuation with increasing depth within the concrete deck. Final GPR maps were produced incorporating a depth-correction technique similar to what is described by Barnes, et. al., Romero, et. al, and Gucunski, et. al., a process which has been clearly demonstrated to better correlate GPR results with not only ground truth (cores, sounding) but also with other NDE technologies. Not only did all the single- and multi-channel system comparisons generate nearly identical deterioration maps when GPR results were compared and examined, but mapped results obtained from other NDE methods on the same deck were used to identify zones where corrosive environment (electrical resistivity - ER) elastic modulus (ultrasonic surface wave - USW), and identified delaminations (impact-echo - IE) had commonality with the GPR results. A summary of the equipment used, as well as general data collection and analysis procedures is provided for the GPR condition assessments. Brief descriptions of background and references to how the complementary NDT technologies are deployed, and how data are interpreted, are also discussed. Comparative maps for all technologies are used for illustrative purposes.

LIF-instrument for Airborne and Ground-Based Measurement of OH and HO2 Radicals in the Troposphere.

NASA Astrophysics Data System (ADS)

Broch, Sebastian; Bachner, Mathias; Dahlhoff, Knut; Holland, Frank; Hofzumahaus, Andreas; Jansen, Peter; Meier, Andreas; Raak, Dominik; Wolters, Jörg; Wahner, Andreas

2010-05-01

The radicals OH and HO2 (also named HOx) play an important role in the chemical degradation and transformation of most trace gases in the troposphere. The rate of these processes depends strongly on the magnitude of the radical concentrations. Due to their high reactivity, their concentrations are very low (sub pptv and pptv range) and exhibit a strong regional variability. Therefore exact measurement of HOx in different regions and at different altitudes in the troposphere are very important for the understanding and modelling of the self cleaning ability of the atmosphere. Here, we present the technical concept and results of laboratory test measurements of a new, mobile instrument for measurement of OH and HO2 radicals based on the proven laser induced fluorescence (LIF) technique (Holland et al., 1995, 2003; Schlosser et al., 2007, 2009). The instrument is planned to be used for ground-based field measurements, for airborne application on a Zeppelin (h = 0-2 km) and on the new German research aircraft HALO (Gulfstream V, h = 0-15 km). The setup of the new instrument is modular to allow different configurations for different applications and all components are newly designed to reduce weight, size and power requirement. For the implementation on HALO completely new air-inlet systems for OH and HO2 were developed at Forschungszentrum Jülich. The OH inlet is based on the shrouded-inlet design by Eisele et al. (1997). The design has been modified to reduce size and weight, and cope with the flight conditions and certification requirements of HALO. These are different than those for the original design, like higher speed, greater ceiling height and strength against bird strike. Compared to our ground-based measurement system, the aircraft inlet requires long inlet tubes which modify the detection sensitivity and possible interferences. Since the sensitivity of our instrument depends on ambient pressure, the OH inlet system is equipped with a calibration system, which allows calibration of the OH measuring channel during flight at different altitudes. Furthermore, both inlet systems allow heating of the inlet tubes and contain flight safety features like de-icing and bird strike resistance. We present results of the characterisation of the new instrument especially with regard to the sensitivity achievable with the long inlet tubes and of laboratory testing of the OH "in-flight" calibration system. Literature: Holland et al., J. Atmos. Sci., 52, 3393, 1995 Holland et al., J. Geophys. Res., 108, 8246, 2003 Schlosser et al., J. Atmos. Chem., 56, 187, 2007 Schlosser et al., Atmos. Chem. Phys., 9, 7923, 2009 Eisele et al., J. Geophys. Res., 102, 27993, 1997

Hydraulic, water-quality, and temperature performance of three types of permeable pavement under high sediment loading conditions

USGS Publications Warehouse

Selbig, William R.; Buer, Nicolas

2018-05-11

Three permeable pavement surfaces - asphalt (PA), concrete (PC), and interlocking pavers (PIP) - were evaluated side-by-side to measure changes to the infiltrative capacity and water quality of stormwater runoff originating from a conventional asphalt parking lot in Madison, Wisconsin. During the 24-month monitoring period (2014-16), all three permeable pavements resulted in statistically significant reductions in the cumulative load of solids (total suspended solids and suspended sediment), total phosphorus, Escherichia coli (E. coli), and Enterococci. Most of the removal occurred through capture and retention in the void spaces of each permeable surface and aggregate base. The largest reduction in total suspended solids was for PC at 80 percent, followed by PIP and PA at 69 and 65 percent, respectively. Reductions (generally less than 50 percent) in total phosphorus also were observed, which might have been tempered by increases in the dissolved fraction observed in PIP and PA. Conversely, PC results indicated a slight reduction in dissolved phosphorus but failed to meet statistical significance. E. coli and Enterococci were reduced by about 80 percent for PC, almost twice the amount observed for PIP and PA.Results for the PIP and PC surfaces initially indicated higher pollutant load reduction than results for the PA surface. The efficiency of PIP and PC surfaces capturing sediment, however, led to a decline in infiltration rates that resulted in more runoff flowing over, not through, the permeable surface. This result led to a decline in treatment until the permeable surface was partially restored through maintenance practices, to which PIP responded more dramatically than PC or PA. Conversely, the PA surface was capable of infiltrating most of the influent runoff volume during the monitoring period and, thus, continued to provide some level of treatment. The combined effect of underdrain and overflow drainage resulted in similar pollutant treatment for all three permeable surfaces.Temperatures below each permeable surface generally followed changes in air temperature with a more gradual response observed in deeper layers. Therefore, permeable pavement may do little to mitigate heated runoff during summer. During winter, deeper layers remained above freezing even when air temperature was below freezing. Although temperatures were not high enough to melt snow or ice accumulated on the surface, temperatures below each permeable pavement did allow void spaces to remain open, which promoted infiltration of melted ice and snow as air temperatures rose above freezing. These open void spaces could potentially reduce the need for application of deicing agents in winter because melted snow and ice would infiltrate, thereby preventing refreezing of pooled water in what is known as the “black ice” effect.

Effects of Road Density and Road-Salt Application Practices on Sodium and Chloride Loads to the Scituate Reservoir, Rhode Island

NASA Astrophysics Data System (ADS)

Waldron, M. C.; Nimiroski, M.

2001-05-01

The Scituate Reservoir drainage basin is the drinking-water source area for two thirds of the population of Rhode Island. The effects of road density and road-salt-application practices on sodium and chloride concentrations in streams in the drainage basin were examined using concentration data collected at intervals of one to six months from January 1982 through June 2000 at 32 stream sites distributed throughout the basin. Median concentrations of sodium and chloride for individual streams during the period of data collection were related to 1995 road densities (road miles per square mile of subbasin) for roads maintained by the Rhode Island Department of Transportation (State-maintained roads) and for roads maintained by the four municipalities in the drainage basin (locally maintained roads). Nearly 60 percent of the variation in median stream sodium and chloride concentrations was accounted for by the variation in density of State-maintained roads (R2= 0.595, p < 0.0001). In contrast, no correlations could be identified between median concentrations of sodium and chloride in streams and the densities of locally maintained roads in the subbasins (R2 = 0.001, p = 0.8771). Also, there was no difference in the relations between median stream sodium concentrations and subbasin road densities for data collected before and after a 1990 State-mandated reduction in the rate of application of sodium during winter deicing of State-maintained roads. Analysis of data on sources of sodium and chloride in the Scituate Reservoir drainage basin during water year 2000 (October 1999 through September 2000) indicates that, while the lengths and densities of locally maintained roads were greater than those of State-maintained roads in most subbasins, the total amount of sodium applied during water year 2000 was nearly three times greater for State-maintained roads than for locally maintained roads. This would be expected, given that State-maintained roads carry more traffic at higher speeds than do locally maintained roads. In addition, the State-maintained roads tend to have more efficient drainage systems that quickly transport runoff directly to the streams. The lack of effect of the reduced sodium application rate on the relation between median stream sodium concentration and density of State-maintained roads may be due to inaccurate monitoring of application rates or to mobilization of sodium previously applied and stored in drainage basin soils. Thus, the amounts of sodium and chloride transported by tributary streams to the Scituate Reservoir depend more on the type of roads and other conditions in the tributary subbasins than on the actual length or density of the roads.

Estimating Concentrations of Road-Salt Constituents in Highway-Runoff from Measurements of Specific Conductance

USGS Publications Warehouse

Granato, Gregory E.; Smith, Kirk P.

1999-01-01

Discrete or composite samples of highway runoff may not adequately represent in-storm water-quality fluctuations because continuous records of water stage, specific conductance, pH, and temperature of the runoff indicate that these properties fluctuate substantially during a storm. Continuous records of water-quality properties can be used to maximize the information obtained about the stormwater runoff system being studied and can provide the context needed to interpret analyses of water samples. Concentrations of the road-salt constituents calcium, sodium, and chloride in highway runoff were estimated from theoretical and empirical relations between specific conductance and the concentrations of these ions. These relations were examined using the analysis of 233 highwayrunoff samples collected from August 1988 through March 1995 at four highway-drainage monitoring stations along State Route 25 in southeastern Massachusetts. Theoretically, the specific conductance of a water sample is the sum of the individual conductances attributed to each ionic species in solution-the product of the concentrations of each ion in milliequivalents per liter (meq/L) multiplied by the equivalent ionic conductance at infinite dilution-thereby establishing the principle of superposition. Superposition provides an estimate of actual specific conductance that is within measurement error throughout the conductance range of many natural waters, with errors of less than ?5 percent below 1,000 microsiemens per centimeter (?S/cm) and ?10 percent between 1,000 and 4,000 ?S/cm if all major ionic constituents are accounted for. A semi-empirical method (adjusted superposition) was used to adjust for concentration effects-superposition-method prediction errors at high and low concentrations-and to relate measured specific conductance to that calculated using superposition. The adjusted superposition method, which was developed to interpret the State Route 25 highway-runoff records, accounts for contributions of constituents other than calcium, sodium, and chloride in dilute waters. The adjusted superposition method also accounts for the attenuation of each constituent's contribution to conductance as ionic strength increases. Use of the adjusted superposition method generally reduced predictive error to within measurement error throughout the range of specific conductance (from 37 to 51,500 ?S/cm) in the highway runoff samples. The effects of pH, temperature, and organic constituents on the relation between concentrations of dissolved constituents and measured specific conductance were examined but these properties did not substantially affect interpretation of the Route 25 data set. Predictive abilities of the adjusted superposition method were similar to results obtained by standard regression techniques, but the adjusted superposition method has several advantages. Adjusted superposition can be applied using available published data about the constituents in precipitation, highway runoff, and the deicing chemicals applied to a highway. This semi-empirical method can be used as a predictive and diagnostic tool before a substantial number of samples are collected, but the power of the regression method is based upon a large number of water-quality analyses that may be affected by a bias in the data.

Surface-water quality in the Lycoming Creek watershed, north-central Pennsylvania, August 1–3, 2011

USGS Publications Warehouse

Risser, Dennis W.; Conlon, Matthew D.

2018-05-17

This report presents the methodology and results for a study of surface-water quality of the Lycoming Creek watershed in north-central Pennsylvania during August 1–3, 2011. The study was done in cooperation with the Williamsport Municipal Water Authority and the Pennsylvania Department of Environmental Protection. Samples of stream water were collected from 31 sites in an area of exploration and production of natural gas from the Marcellus Shale – 5 sites on the main stem of Lycoming Creek and 26 sites on tributary streams. The samples provide a snapshot of the base-flow water-quality conditions, which helps document the spatial variability in water-quality and could be useful for assessing future changes.The 272-square mile Lycoming Creek watershed is located within Lycoming, Tioga, and Sullivan Counties in north-central Pennsylvania. Lycoming Creek flows 37.5 miles to its confluence with the West Branch Susquehanna River in the city of Williamsport. A well field that supplies water for Williamsport captures some water that has infiltrated the streambed of Lycoming Creek. Because the stream provides a source of water to the well field, this study focused on the stream-water quality as it relates to drinking-water standards as opposed to aquatic life.Surface-water samples collected at 20 sites by the U.S. Geological Survey and 11 sites by the Pennsylvania Department of Environmental Protection were analyzed by each agency for a suite of constituents that included major ions, trace metals, nutrients, and radiochemicals. None of the analytical results failed to meet standards set by the U.S. Environmental Protection Agency as maximum contaminant levels for drinking water.Results of the sampling show the substantial spatial variability in base-flow water quality within the Lycoming Creek watershed caused by the interrelated effects of physiography, geology and land use. Dissolved-solids concentrations ranged from less than the laboratory reporting level of 12 milligrams per liter (mg/L) in Wolf Run, a pristine forested watershed, to 202 mg/L in Bottle Run, a watershed with more development near Williamsport. Concentrations of the major ions ranged over at least one order of magnitude; chloride had the largest range from 0.3 to 45.4 mg/L, with nine samples exceeding the natural background level of about 5 mg/L, most likely because of the application of deicing salt to roads. Trace constituents were even more variable, with concentrations for aluminum, cobalt, and manganese ranging over almost four orders of magnitude. Samples from Red Run and Dutchman Run, watersheds that experienced past coal mining activity, had concentrations of 11 metals that were significantly greater than in samples collected from other streams. Samples from Bottle Run, the tributary of Lycoming Creek nearest to Williamsport, contained elevated levels of chloride and boron, constituents associated with urban development.

Voltage management of distribution networks with high penetration of distributed photovoltaic generation sources

NASA Astrophysics Data System (ADS)

Alyami, Saeed

Installation of photovoltaic (PV) units could lead to great challenges to the existing electrical systems. Issues such as voltage rise, protection coordination, islanding detection, harmonics, increased or changed short-circuit levels, etc., need to be carefully addressed before we can see a wide adoption of this environmentally friendly technology. Voltage rise or overvoltage issues are of particular importance to be addressed for deploying more PV systems to distribution networks. This dissertation proposes a comprehensive solution to deal with the voltage violations in distribution networks, from controlling PV power outputs and electricity consumption of smart appliances in real time to optimal placement of PVs at the planning stage. The dissertation is composed of three parts: the literature review, the work that has already been done and the future research tasks. An overview on renewable energy generation and its challenges are given in Chapter 1. The overall literature survey, motivation and the scope of study are also outlined in the chapter. Detailed literature reviews are given in the rest of chapters. The overvoltage and undervoltage phenomena in typical distribution networks with integration of PVs are further explained in Chapter 2. Possible approaches for voltage quality control are also discussed in this chapter, followed by the discussion on the importance of the load management for PHEVs and appliances and its benefits to electric utilities and end users. A new real power capping method is presented in Chapter 3 to prevent overvoltage by adaptively setting the power caps for PV inverters in real time. The proposed method can maintain voltage profiles below a pre-set upper limit while maximizing the PV generation and fairly distributing the real power curtailments among all the PV systems in the network. As a result, each of the PV systems in the network has equal opportunity to generate electricity and shares the responsibility of voltage regulation. The method does not require global information and can be implemented either under a centralized supervisory control scheme or in a distributed way via consensus control. Chapter 4 investigates autonomous operation schedules for three types of intelligent appliances (or residential controllable loads) without receiving external signals for cost saving and for assisting the management of possible photovoltaic generation systems installed in the same distribution network. The three types of controllable loads studied in the chapter are electric water heaters, refrigerators deicing loads, and dishwashers, respectively. Chapter 5 investigates the method to mitigate overvoltage issues at the planning stage. A probabilistic method is presented in the chapter to evaluate the overvoltage risk in a distribution network with different PV capacity sizes under different load levels. Kolmogorov--Smirnov test (K--S test) is used to identify the most proper probability distributions for solar irradiance in different months. To increase accuracy, an iterative process is used to obtain the maximum allowable injection of active power from PVs. Conclusion and discussions on future work are given in Chapter 6.

Expanding Spatial and Temporal Coverage of Arctic CH4 and CO2 Fluxes

NASA Astrophysics Data System (ADS)

Murphy, P.; Oechel, W. C.; Moreaux, V.; Losacco, S.; Zona, D.

2013-12-01

Carbon storage and exchange in Arctic ecosystems is the subject of intensive study focused on determining rates, controls, and mechanisms of CH4 and CO2 fluxes. The Arctic contains more than 1 Gt of Carbon in the upper meter of soil, both in the active layer and permafrost (Schuur et al., 2008; Tarnocai et al., 2009). However, the annual pattern and controls on the release of CH4 is inadequately understood in Arctic tundra ecosystems. Annual methane budgets are poorly understood, and very few studies measure fluxes through the freeze-up cycle during autumn months (Mastepanov et al., 2008; Mastepanov et al., 2010; Sturtevant et al., 2012). There is no known, relatively continuous, CH4 flux record for the Arctic. Clearly, the datasets that currently exist for budget calculations and model parameterization and verification are inadequate. This is likely due to the difficult nature of flux measurements in the Arctic. In September 2012, we initiated a research project towards continuous methane flux measurements along a latitudinal transect in Northern Alaska. The eddy-covariance (EC) technique is challenging in such extreme weather conditions due to the effects of ice formation and precipitation on instrumentation, including gas analyzers and sonic anemometers. The challenge is greater in remote areas of the Arctic, when low power availability and limited communication can lead to delays in data retrieval or data loss. For these reasons, a combination of open- and closed-path gas analyzers, and several sonic anemometers (including one with heating), have been installed on EC towers to allow for cross-comparison and cross-referencing of calculated fluxes. Newer instruments for fast CH4 flux determination include: the Los Gatos Research Fast Greenhouse Gas Analyzer and the Li-Cor LI-7700. We also included the self-heated Metek Class-A uSonic-3 Anemometer as a new instrument. Previously existing instruments used for comparison include the Li-Cor LI-7500; Li-Cor LI-7200; Gill WindmasterPro; Gill R3; Campbell Scientific CSAT-3, and METEK USA-1. To prevent gaps in data due to poor weather, we developed a temperature control system to allow de-icing of the sonic instrument based on data quality. Enclosures were also created to support equipment that was not designed for outdoor use. A similar temperature control system was implemented to maintain stable conditions in the enclosures. Five existing EC towers on the north slope of Alaska, in Barrow, Atqasuk, and Ivotuk, are used to obtain CH4 and CO2 fluxes, and allow a comparison of fluxes across sensor type and design. Here we present the instrument set-up and some of the preliminary eddy covariance CH4 and CO2 flux data, which might prove very useful as guidelines for further flux measurements in northern high latitudes.

The formation and fate of chlorinated organic substances in temperate and boreal forest soils.

PubMed

Clarke, Nicholas; Fuksová, Kvetoslava; Gryndler, Milan; Lachmanová, Zora; Liste, Hans-Holger; Rohlenová, Jana; Schroll, Reiner; Schröder, Peter; Matucha, Miroslav

2009-03-01

Chlorine is an abundant element, commonly occurring in nature either as chloride ions or as chlorinated organic compounds (OCls). Chlorinated organic substances were long considered purely anthropogenic products; however, they are, in addition, a commonly occurring and important part of natural ecosystems. Formation of OCls may affect the degradation of soil organic matter (SOM) and thus the carbon cycle with implications for the ability of forest soils to sequester carbon, whilst the occurrence of potentially toxic OCls in groundwater aquifers is of concern with regard to water quality. It is thus important to understand the biogeochemical cycle of chlorine, both inorganic and organic, to get information about the relevant processes in the forest ecosystem and the effects on these from human activities, including forestry practices. A survey is given of processes in the soil of temperate and boreal forests, predominantly in Europe, including the participation of chlorine, and gaps in knowledge and the need for further work are discussed. Chlorine is present as chloride ion and/or OCls in all compartments of temperate and boreal forest ecosystems. It contributes to the degradation of SOM, thus also affecting carbon sequestration in the forest soil. The most important source of chloride to coastal forest ecosystems is sea salt deposition, and volcanoes and coal burning can also be important sources. Locally, de-icing salt can be an important chloride input near major roads. In addition, anthropogenic sources of OCls are manifold. However, results also indicate the formation of chlorinated organics by microorganisms as an important source, together with natural abiotic formation. In fact, the soil pool of OCls seems to be a result of the balance between chlorination and degradation processes. Ecologically, organochlorines may function as antibiotics, signal substances and energy equivalents, in descending order of significance. Forest management practices can affect the chlorine cycle, although little is at present known about how. The present data on the apparently considerable size of the pool of OCls indicate its importance for the functioning of the forest soil system and its stability, but factors controlling their formation, degradation and transport are not clearly understood. It would be useful to estimate the significance and rates of key processes to be able to judge the importance of OCls in SOM and litter degradation. Effects of forest management processes affecting SOM and chloride deposition are likely to affect OCls as well. Further standardisation and harmonisation of sampling and analytical procedures is necessary. More work is necessary in order to understand and, if necessary, develop strategies for mitigating the environmental impact of OCls in temperate and boreal forest soils. This includes both intensified research, especially to understand the key processes of formation and degradation of chlorinated compounds, and monitoring of the substances in question in forest ecosystems. It is also important to understand the effect of various forest management techniques on OCls, as management can be used to produce desired effects.

Induced infiltration from the Rockaway River and water chemistry in a stratified-drift aquifer at Dover, New Jersey, with a section on modeling ground-water flow in the Rockaway River Valley

USGS Publications Warehouse

Dysart, Joel E.; Rheaume, Stephen J.; Kontis, Angelo L.

1999-01-01

The vertical hydraulic conductivity per unit thickness (streambed leakance) of unconsolidated sediment immediately beneath the channel of the Rockaway River near a municipal well field at Dover, N.J., is between 0.2 and 0.6 feet per day per foot and is probably near the low end of this range. This estimate is based on evaluation of three lines of evidence: (1) Streamflow measurements, which indicated that induced infiltration of river water near the well field averaged 0.67 cubic feet per second; (2) measurements of the rate of downward propagation of diurnal fluctuations in dissolved oxygen and water temperature at three piezometers, which indicated vertical Darcian flow velocities of 0.6 and 1.5 feet per day, respectively; and (3) chemical mixing models based on stable isotopes of oxygen and hydrogen, which indicated that 30 percent of the water reaching a well near the center of the well field was derived from the river. The estimated streambed-leakance values are compatible with other aquifer properties and with hydraulic stresses observed over a 2-year period, as demonstrated by a set of six alternative groundwater flow models of the Rockaway River valley. Simulated water levels rose 0.5 to 1.7 feet near the well field when simulated streambed leakance was changed from 0.2 to 0.6 feet per day per foot, or when a former reach of the Rockaway River valley that is now blocked by glacial drift was simulated as containing a continuous sand aquifer (rather than impermeable till). Model recalibration to observed water levels could accommodate either of these changes, however, by plausible adjustments in hydraulic conductivity of 35 percent or less.The ground-water flow models incorporate a new procedure for simulating areal recharge, in which water available for recharge in any time interval is accepted as recharge only where the water level in the uppermost model layer is below land surface. Water rejected as recharge on upland hillsides is allowed to recharge aquifers at the base of the hillsides. Inclusion of uplands in models of valley-fill aquifers and use of the new procedure increases model complexity and data requirements, but automates the simulation of recharge to those aquifers from the uplands, even in transient-state simulations with multiple periods of varied stresses, and facilitates delineation of upland areas that contribute water to well fields. The area from which ground water flowed toward the Dover well field decreased with an increase in simulated streambed leakance or an increase in simulated hydraulic conductivity of upland till. Concentrations of solutes in ground water near the Dover well field reflect the mixing of native ground water with water infiltrated from the Rockaway River. Chemical reactions in the aquifer, chiefly the weathering of carbonate minerals by dissolved carbon dioxide, affect the pH and the concentrations of both solutes and dissolved gases. Concentrations of sodium, chloride, and sulfate appear to be related to man's activities, such as road deicing, or to decay of organic matter in the aquifer.

Effects of highway runoff on streamflow and water quality in the Sevenmile Creek basin, a rural area in the Piedmont Province of North Carolina, July 1981 to July 1982

USGS Publications Warehouse

Harned, Douglas

1988-01-01

An evaluation of water-quality data from streams that receive stormwater runoff from a segment of Interstate Highway 85 in North Carolina indicated increased levels of many constituents compared to levels in nearby undeveloped basins. Additional data collected from a network of dry and wet atmospheric deposition collectors, lysimeter samples, soil surveys, wind measurements, and road sweepings helped define the general sources and migration of chemical substances near the highway. The eight study basins, located in a rural area in the Piedmont of North Carolina, had a combined area of 17.5 square miles and drained a 4.8-mile-long segment of the interstate. The average traffic flow along this section was 25,000 vehicles per day. During storm runoff, streamflow in basins traversed by the highway rose and fell more rapidly than that in the undeveloped basins. This more rapid response is due to the impervious, paved area of the basins and the manmade drainage systems designed to rapidly move water off the highway. Alkalinity, specific conductance, and concentrations of calcium, sodium, and chloride were greater at the highway stations than in the undeveloped basins as a result of highway salting for control of ice. Specific conductance and concentrations of dissolved and total nitrogen peaked at the beginning of each storm event. The data indicated that, for the study basins, highway runoff had little or no effect on suspended sediment, water temperature, dissolved oxygen, and pH. However, the pH at all stations decreased during stormflow because the rainfall drained off by the streams had pH values less than 5.7. High metals concentrations were found in the soils within 100 feet of the highway and in the soil water infiltrating the soil zone. Chromium, copper, nickel, and zinc concentrations in the streams near the highway generally were above the maximum levels recommended by the U.S. Environmental Protection Agency (EPA) for the protection of aquatic life. Lead and cadmium concentrations frequently exceeded the maximum levels recommended by the EPA for drinking water. The highway is a source of contaminants to surrounding areas. Particulate and metal loads in dustfall and chemical-constituent concentrations in soils decrease exponentially with distance from the highway. The highest concentrations of contaminants were found on the downwind side. Increased concentrations of metals (cadmium, chromium, iron, lead, nickel, and zinc) in rainfall were observed in samples collected near the highway and in samples collected approximately one-half mile away. Material loading due to dustfall was greater than loading due to rainfall. Loading due to saltated particles, those heavier particles bounced along the highway surface, was higher than loading due to dustfall. Saltation loads were greatest during the winter months because of highway deicing and sanding, which supplied an estimated two-thirds of the saltated materials. The remaining one-third of the saltated load came primarily from the deposition of particles from vehicles. Some of the greatest constituent concentrations were measured in the soil water sampled from the lysimeters located adjacent to the highway.

MEMS Applications in Aerodynamic Measurement Technology

NASA Technical Reports Server (NTRS)

Reshotko, E.; Mehregany, M.; Bang, C.

1998-01-01

Microelectromechanical systems (MEMS) embodies the integration of sensors, actuators, and electronics on a single substrate using integrated circuit fabrication techniques and compatible bulk and surface micromachining processes. Silicon and its derivatives form the material base for the MEMS technology. MEMS devices, including microsensors and microactuators, are attractive because they can be made small (characteristic dimension about 100 microns), be produced in large numbers with uniform performance, include electronics for high performance and sophisticated functionality, and be inexpensive. For aerodynamic measurements, it is preferred that sensors be small so as to approximate measurement at a point, and in fact, MEMS pressure sensors, wall shear-stress sensors, heat flux sensors and micromachined hot wires are nearing application. For the envisioned application to wind tunnel models, MEMS sensors can be placed on the surface or in very shallow grooves. MEMS devices have often been fabricated on stiff, flat silicon substrates, about 0.5 mm thick, and therefore were not easily mounted on curved surfaces. However, flexible substrates are now available and heat-flux sensor arrays have been wrapped around a curved turbine blade. Electrical leads can also be built into the flexible substrate. Thus MEMS instrumented wind tunnel models do not require deep spanwise grooves for tubes and leads that compromise the strength of conventionally instrumented models. With MEMS, even the electrical leads can potentially be eliminated if telemetry of the signals to an appropriate receiver can be implemented. While semiconductor silicon is well known for its electronic properties, it is also an excellent mechanical material for MEMS applications. However, silicon electronics are limited to operations below about 200 C, and silicon's mechanical properties start to diminish above 400 C. In recent years, silicon carbide (SiC) has emerged as the leading material candidate for applications in high temperature environments and can be used for high-temperature MEMS applications. With SiC, diodes and more complex electronics have been shown to operate to about 600 C, while the mechanical properties of SiC are maintained to much higher temperatures. Even when MEMS devices show benefits in the laboratory, there are many packaging challenges for any aeronautics application. Incorporating MEMS into these applications requires new approaches to packaging that goes beyond traditional integrated circuit (IC) packaging technologies. MEMS must interact mechanically, as well as electrically with their environment, making most traditional chip packaging and mounting techniques inadequate. Wind tunnels operate over wide temperature ranges in an environment that is far from being a 'clean-room.' In flight, aircraft are exposed to natural elements (e.g. rain, sun, ice, insects and dirt) and operational interferences(e.g. cleaning and deicing fluids, and maintenance crews). In propulsion systems applications, MEMS devices will have to operate in environments containing gases with very high temperatures, abrasive particles and combustion products. Hence deployment and packaging that maintains the integrity of the MEMS system is crucial. This paper presents an overview of MEMS fabrication and materials, descriptions of available sensors with more details on those being developed in our laboratories, and a discussion of sensor deployment options for wind tunnel and flight applications.

Quality of stormwater runoff discharged from Massachusetts highways, 2005-07

USGS Publications Warehouse

Smith, Kirk P.; Granato, Gregory E.

2010-01-01

The U.S. Geological Survey (USGS), in cooperation with U.S. Department of Transportation Federal Highway Administration and the Massachusetts Department of Transportation, conducted a field study from September 2005 through September 2007 to characterize the quality of highway runoff for a wide range of constituents. The highways studied had annual average daily traffic (AADT) volumes from about 3,000 to more than 190,000 vehicles per day. Highway-monitoring stations were installed at 12 locations in Massachusetts on 8 highways. The 12 monitoring stations were subdivided into 4 primary, 4 secondary, and 4 test stations. Each site contained a 100-percent impervious drainage area that included two or more catch basins sharing a common outflow pipe. Paired primary and secondary stations were located within a few miles of each other on a limited-access section of the same highway. Most of the data were collected at the primary and secondary stations, which were located on four principal highways (Route 119, Route 2, Interstate 495, and Interstate 95). The secondary stations were operated simultaneously with the primary stations for at least a year. Data from the four test stations (Route 8, Interstate 195, Interstate 190, and Interstate 93) were used to determine the transferability of the data collected from the principal highways to other highways characterized by different construction techniques, land use, and geography. Automatic-monitoring techniques were used to collect composite samples of highway runoff and make continuous measurements of several physical characteristics. Flowweighted samples of highway runoff were collected automatically during approximately 140 rain and mixed rain, sleet, and snowstorms. These samples were analyzed for physical characteristics and concentrations of 6 dissolved major ions, total nutrients, 8 total-recoverable metals, suspended sediment, and 85 semivolatile organic compounds (SVOCs), which include priority polyaromatic hydrocarbons (PAHs), phthalate esters, and other anthropogenic or naturally occurring organic compounds. The distribution of particle size of suspended sediment also was determined for composite samples of highway runoff. Samples of highway runoff were collected year round and under various dry antecedent conditions throughout the 2-year sampling period. In addition to samples of highway runoff, supplemental samples also were collected of sediment in highway runoff, background soils, berm materials, maintenance sands, deicing compounds, and vegetation matter. These additional samples were collected near or on the highways to support data analysis. There were few statistically significant differences between populations of constituent concentrations in samples from the primary and secondary stations on the same principal highways (Mann-Whitney test, 95-percent confidence level). Similarly, there were few statistically significant differences between populations of constituent concentrations for the four principal highways (data from the paired primary and secondary stations for each principal highway) and populations for test stations with similar AADT volumes. Exceptions to this include several total-recoverable metals for stations on Route 2 and Interstate 195 (highways with moderate AADT volumes), and for stations on Interstate 95 and Interstate 93 (highways with high AADT volumes). Supplemental data collected during this study indicate that many of these differences may be explained by the quantity, as well as the quality, of the sediment in samples of highway runoff. Nonparametric statistical methods also were used to test for differences between populations of sample constituent concentrations among the four principal highways that differed mainly in traffic volume. These results indicate that there were few statistically significant differences (Mann-Whitney test, 95-percent confidence level) for populations of concentrations of most total-recoverable metals

Numerical study of the thermal behavior of a new deicing road structure design with energy harvesting capabilities

NASA Astrophysics Data System (ADS)

Le Touz, Nicolas; Dumoulin, Jean

2015-04-01

Facing the heavy organisational, financial and environmental constraints imposed by usual winter maintenance salting operations, pavement engineers have been led to look for alternative solutions to avoid ice or snow deposit at pavements surface. Among the solutions, one is self-de-icing heating pavements, for which two technologies have been developed so far: one is based on embedded coils circulating a heated calorific fluid under the pavement surface; the other one relies on the use of embedded resistant electric wires. The use and operation of such systems in the world is still limited and was only confined to small road stretches or specific applications, such as bridges which are particularly sensitive to frost. One of the most significant "coil technology" example in Europe is the SERSO-System (Solar Energy recovery from road surfaces) built in 1994, on a Switzerland bridge. Many of these experiences are referenced in the technical literature, which provides state-of-the art papers (see for instance Eugster) and useful detailed information dealing with the construction and operational management of such installation. The present study is taking part of the Forever Open Road Concept addressed by the R5G: 5th Generation Road [1], one of the major project supported by IFSTTAR. It considers a different design of self-de-icing road that simplify its mode of construction and maintenance, compared to the two technologies mentioned above. It should also be noted that similar to pavements instrumented with coils, such structure could be used in the reversible way to capture the solar energy at the pavement surface during sunny days and store it, to either warm the pavement at a later stage or for exogenous needs (e.g. contribution to domestic hot water). To complete our study we also considered the use of semi-transparent pavement course wearing in place of the traditional opaque one. In the present study, a 2D model was developed using FEM approach. It combines 2 numerical models. One is dedicated to the calculation of the heat transfer inside the porous layer between the fluid and the structure according to the geometry studied and the physical properties of the components of the system. The second one addresses the heat transfer inside the different layer of the pavement and was adapted to allow the insertion of a semi-transparent surface layer (for sun radiation). The temperature spatial distribution within the structure and its surface is calculated at different time step according to the evolution of boundary conditions at its surface. Various location in France were selected and calculation of the temperature field was carried-out over a year. Discussion on the performances of such system versus its location is proposed. Influence of a semi-transparent layer is also discussed. Future works will compared numerical simulations with experiments thank to a dedicated test bench under development and that will allow to test various structure in parallel. References [1] W. J. Eugster, Road and Bridge Heating Geothermal Energy. Overview and examples, European Geothermal Congress 2007 [2] http://www.ifsttar.fr/en/recherche-expertise/colonne-1/nos-grands-projets/r5g-5th-generation-road/

Initial evaluation of airborne water vapour measurements by the IAGOS-GHG CRDS system

NASA Astrophysics Data System (ADS)

Filges, Annette; Gerbig, Christoph; Smit, Herman G. J.; Krämer, Martina; Spelten, Nicole

2013-04-01

Accurate and reliable airborne measurements of water vapour are still a challenge. Presently, no airborne humidity sensor exists that covers the entire range of water vapour content between the surface and the upper troposphere/lower stratosphere (UT/LS) region with sufficient accuracy and time resolution. Nevertheless , these data are a pre-requisite to study the underlying processes in the chemistry and physics of the atmosphere. The DENCHAR project (Development and Evaluation of Novel Compact Hygrometer for Airborne Research) addresses this deficit by developing and characterizing novel or improved compact airborne hygrometers for different airborne applications within EUFAR (European Facility for Airborne Research). As part of the DENCHAR inter-comparison campaign in Hohn (Germany), 23 May - 1 June 2011, a commercial gas analyzer (G2401-m, Picarro Inc.,US), based on cavity ring-down spectroscopy (CRDS), was installed on a Learjet to measure water vapour, CO2, CH4 and CO. The CRDS components are identical to those chosen for integration aboard commercial airliner within IAGOS (In-service Aircraft for a Global Observing System). Thus the campaign allowed for the initial assessment validation of the long-term IAGOS H2O measurements by CRDS against reference instruments with a long performance record (FISH, the Fast In-situ Stratospheric Hygrometer, and CR2 frostpoint hygrometer, both research centre Juelich). The inlet system, a one meter long 1/8" FEP-tube connected to a Rosemount TAT housing (model 102BX, deiced) installed on a window plate of the aircraft, was designed to eliminate sampling of larger aerosols, ice particles, and water droplets, and provides about 90% of ram-pressure. In combination with a lowered sample flow of 0.1 slpm (corresponding to a 4 second response time), this ensured a fully controlled sample pressure in the cavity of 140 torr throughout an aircraft altitude operating range up to 12.5 km without the need of an upstream sampling pump. This setup ensures full compatibility with the future deployment of the analyser within IAGOS. For the initial water calibration of the instrument, a calibration of a similar instrument performed at MPI-BGC Jena against a dew point mirror (Dewmet, Michell instruments Ltd., UK) in the range from 0.7 to 3.0% was transferred to all subsequently manufactured CRDS instruments by Picarro. During the campaign the analyzer was compared against a reference frost point hygrometer, which is also used for calibration of the reference instrument FISH. The dew point mirror calibration was within 0.7 % of the FISH calibrator, but showed an offset of 14.45 ppm, which is consistent with the H2O content of dry tank air and diffusion effects through the inlet line (FEP). Furthermore, a new independent calibration method, based on the dilution effect of water vapour on CO2, was tested. It showed a 9 % low bias compared to the dew point mirror calibration. Comparison of the in-flight data against the reference systems showed that the analyzer is reliable and has a good long-term stability. Flight data from the DENCHAR campaign suggest a conservative precision estimate for measurements made at 0.4 Hz of 4 ppm for H2O < 100 ppm, and 4 % (relative) for H2O > 100 ppm. Accuracy at mixing ratios below 50 ppm was difficult to assess, as the reference instruments suffered from lack of stability. We present the results of the campaign flights and comparison with the reference instruments. The different calibration methods will be discussed.

Assessment of surface-water quantity and quality, Eagle River watershed, Colorado, 1947-2007

USGS Publications Warehouse

Williams, Cory A.; Moore, Jennifer L.; Richards, Rodney J.

2011-01-01

The spatial patterns for concentrations of trace metals (aluminum, cadmium, copper, iron, manganese, and zinc) indicate an increase in dissolved concentrations of these metals near historical mining areas in the Eagle River and several tributaries near Belden. In general, concentrations decrease downstream from mining areas. Concentrations typically are near or below reporting limits in Gore Creek and other tributaries within the watershed. Concentrations for trace elements (arsenic, selenium, and uranium) in the watershed usually are below the reporting limit, and no prevailing spatial patterns were observed in the data. Step-trend analysis and temporal-trend analysis provide evidence that remediation of historical mining areas in the upper Eagle River have led to observed decreases in metals concentrations in many surface-waters. Comparison of pre- and post-remediation concentrations for many metals indicates significant decreases in metals concentrations for cadmium, manganese, and zinc at sites downstream from the Eagle Mine Superfund Site. Some sites show order of magnitude reductions in median concentrations between these two periods. Evaluation of monotonic trends for dissolved metals concentrations show downward trends at numerous sites in, and downstream from, historic mining areas. The spatial pattern of nutrients shows lower concentrations on many tributaries and on the Eagle River upstream from Red Cliff with increases in nutrients downstream of major urban areas. Seasonal variations show that for many nutrient species, concentrations tend to be lowest May-June and highest January-March. The gradual changes in concentrations between seasons may be related to dilution effects from increases and decreases in streamflow. Upward trends in nutrients between the towns of Gypsum and Avon were detected for nitrate, orthophosphate, and total phosphorus. An upward trend in nitrite was detected in Gore Creek. No trends were detected in un-ionized ammonia within the ERW. Exceedances of State water-quality standards (nitrite, nitrate, and un-ionized ammonia) and levels higher than U.S. Environmental Protection Agency recommendations (total phosphorus) occur in several areas within the ERW. The majority of the exceedances are from comparisons to the U.S. Environmental Protection Agency total phosphorus recommendations. A positive correlation was observed between suspended sediment and total phosphorus. An upward trend in total dissolved solids in Gore Creek may be the result of increases in chloride salts. Highly significant trends were detected in sodium, potassium, and chloride with a significant upward trend in magnesium and a weakly significant upward trend in calcium. A quantitative analysis of the relative abundance of calcium, magnesium, sodium, and potassium to the available anions suggests that chloride salts likely are the source for the detected upward trends because chloride is the only commonly occurring anion with a trend in Gore Greek. A potential source for the observed chloride salts may be the chemical anti-icing and deicing products used during winter road maintenance in municipal areas and on Interstate-70. A downward trend in dissolved solids in the Eagle River between Gypsum and Avon may be contributing to the detected trend on the Eagle River at Gypsum. Significant downward trends were detected in specific ions such as calcium, magnesium, sulfate, and silica. Measures of total dissolved solids as well as comparisons to specific ions show that in water-quality samples within the ERW concentrations generally are lower in the headwaters, with increases downstream from Wolcott. Differences in concentrations likely result from increased abundance of salt-bearing geologic units downstream from Avon. Few sites had measured concentrations that exceeded the State standards for chloride.