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1

33 CFR 263.26 - Small beach erosion control project authority (Section 103).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Small beach erosion control project authority (Section...Protection Policy § 263.26 Small beach erosion control project authority (Section...undertake construction of small shore and beach restoration and protection...

2011-07-01

2

33 CFR 263.26 - Small beach erosion control project authority (Section 103).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Small beach erosion control project authority (Section...Protection Policy § 263.26 Small beach erosion control project authority (Section...undertake construction of small shore and beach restoration and protection...

2013-07-01

3

33 CFR 263.26 - Small beach erosion control project authority (Section 103).  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF DEFENSE CONTINUING AUTHORITIES PROGRAMS Shore Protection Policy § 263.26 Small beach erosion control...of the Army is authorized to undertake construction of small shore and beach restoration and protection projects not...

2010-07-01

4

Beach Erosion Project, Delaware Coast Protection Project, Delaware.  

National Technical Information Service (NTIS)

The project provides for improvements along the Atlantic Coast of Delaware extending from Cape Henlopen to the Maryland State Line at Fenwick Island. Those improvements include combined beach erosion control and hurricane protection and consists of wideni...

1971-01-01

5

Weathering and Erosion Video Project  

NSDL National Science Digital Library

Using a digital video recorder, 6th grade students will create an informational video that teaches 4th grade (or 5th as an FCAT review) students about weathering and erosion using images from around the school and local areas. This will most likely be a long-term project, depending on how many digital video recorders and computers are available.

Thibedeau, Amber

2012-07-25

6

Erosion Control for Local Roads  

E-print Network

Erosion Control Handbook for Local Roads M I N N E S OT A DEPARTME N T OF T R A N S PORTATION was extremely helpful in identifying key issues and concerns of those responsible for controlling erosion on low. This report does not constitute a standard, specification, or regulation. 2 #12;Table of Contents Erosion

Minnesota, University of

7

Lincoln Park shoreline erosion control project: Monitoring for surface substrate, infaunal bivalves and eelgrass, 1993  

SciTech Connect

In 1988, the US Army Corps of Engineers and the City of Seattle placed material on the upper beach at Lincoln Park, in West Seattle, Washington. The fill served to mitigate shoreline erosion that had caused undercutting and collapse of the seawall in several places. A series of pre- and post-construction studies have been conducted to assess the impacts to marine biota of fill placement and movement of surface substrate. This study was designed to monitor infaunal bivalves and eelgrass from intertidal areas in and adjacent to the area of original fill placement. Findings from this survey were compared to previous survey results to determine (1) if recruitment of infaunal bivalves to the fill area has occurred, (2) if infaunal bivalve densities outside the fill area are stable, and (3) if eelgrass distribution and abundance have remained stable along the adjacent shoreline. To maximize comparability of findings from this survey with previous studies, sampling techniques, transects, and tidal elevations were consistent with previous studies at this site.

Antrim, L.D.; Thom, R.M.; Gardiner, W.W. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

1993-09-01

8

33 CFR 263.26 - Small beach erosion control project authority (Section 103).  

Code of Federal Regulations, 2012 CFR

33 Navigation and Navigable Waters 3 2012-07-01...103). 263.26 Section 263.26 Navigation and Navigable Waters CORPS OF ENGINEERS...total project costs shall include both initial construction and periodic...

2012-07-01

9

Ceramic corrosion/erosion project description  

SciTech Connect

As a part of the United States Department of Energy's High Temperature Turbine Technology Program, the Morgantown Energy Technology Center is participating in a Ceramics Corrosion/Erosion Materials Study. Objective is to create a technology base for ceramic materials which could be used by stationary gas power turbines operating with a high-temperature, coal-derived, low-Btu gas products of combustion environment. Two facilities are designed and installed to burn a varying low-Btu coal-derived gas in a controlled manner. This report contains the objectives and testing philosophy as well as the operating, specimen handling, and emergency procedures for the facilities. The facilities were checked out in August/September 1980. Testing is scheduled to begin in late 1980 with completion of 1000 hours of ceramic materials exposure to be completed by early 1981. Most of the enclosed is an update of two METC Information Releases (IR), i.e., IR 442 (1979) Test Plan for Ceramic Corrosion/Erosion Project, and IR 817 (1980) Ceramic Corrosion/Erosion Project Description.

Nakaishi, C.V.; Carpenter, L.K.

1981-02-01

10

The International Erosion Control Society - Photo Gallery  

NSDL National Science Digital Library

Users can access photographs of various forms of erosion, erosion damage, and "before and after" photos showing how the problem was brought under control. Each photograph is accompanied by a description of the activity which is taking place.

11

Robotic weld overlay coatings for erosion control  

SciTech Connect

The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB`s.

Not Available

1994-11-01

12

Robotic weld overlay coatings for erosion control  

NASA Astrophysics Data System (ADS)

The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB's.

13

Robotic weld overlay coatings for erosion control  

SciTech Connect

Twelve weld overlay hardfacing alloys have been selected for preliminary erosion testing based on a literature review These alloys have been separated into three major groups: (1) Cobalt containing alloys, (2) Nickel-base alloys, (3) Iron base alloys. These alloys are being applied to carbon steel substrates and will undergo preliminary erosion testing to identify candidates weld overlay alloys for erosion control in CFB boilers. The candidate alloys selected from the preliminary erosion tests will then undergo more detailed evaluations in future research.

Levin, B.F.; Dupont, J.N.; Marder, A.R.

1993-04-18

14

Airphoto analysis of erosion control practices  

NASA Technical Reports Server (NTRS)

The Universal Soil Loss Equation (USLE) is a widely accepted tool for erosion prediction and conservation planning. In this study, airphoto analysis of color and color infrared 70 mm photography at a scale of 1:60,000 was used to determine the erosion control practice factor in the USLE. Information about contour tillage, contour strip cropping, and grass waterways was obtained from aerial photography for Pheasant Branch Creek watershed in Dane County, Wisconsin.

Morgan, K. M.; Morris-Jones, D. R.; Lee, G. B.; Kiefer, R. W.

1980-01-01

15

VETIVER SYSTEM FOR EROSION AND SEDIMENT CONTROL  

Microsoft Academic Search

The Vetiver System (VS) is based on the use of vetiver grass (Vetiveria zizanioides L.) for various applications in erosion and sediment control. VS was first developed by the World Bank for soil and water conservation in India in the 1980s. Research and Development conducted in Queensland and overseas since then have also shown VS to be a very effective

P. N. V. TruongA; R. Loch

16

National Shoreline Erosion Control Demonstration Program Overview.  

National Technical Information Service (NTIS)

The National Shoreline Erosion Control Development and Demonstration Program of the US Army Corps of Engineers was established by Section 227 of the US Water Resources and Development Act (WRDA) of 1996 with initial funding appropriated in FY00. Section 2...

G. Turk, J. Pope, W. R. Curtis

2000-01-01

17

Rainfall Controls Cascade Mountains' Erosion and Bedrock Uplift Patterns  

NSF Publications Database

... 703) 292-8552 dfountai@nsf.gov Rainfall Controls Cascade Mountains' Erosion and Bedrock Uplift ... The data strongly suggest that precipitation controls erosion rates across the Cascades, and that ...

18

Technological Solutions for Erosion Control and Water Clarification using Polyacrylamide (PAM) and PAM blends  

Microsoft Academic Search

Years of research, corporate publications, patents and trademarks have led to a greatly improved and cost efficient erosion control technology. Development of new polyacrylamide (PAM) blends and delivery methodologies has resulted in a whole new class of in-situ erosion control and water clarification tools. Multi-disciplinary environmental industry projects for mining, construction, water treatment and biological research have proven this class

William Gowdy; Jerry Hanna; Steven R. Iwinski; Dave Martin

19

Fallout radionuclide-based techniques for assessing the impact of soil conservation measures on erosion control and soil quality: an overview of the main lessons learnt under an FAO/IAEA Coordinated Research Project.  

PubMed

This paper summarizes key findings and identifies the main lessons learnt from a 5-year (2002-2008) coordinated research project (CRP) on "Assessing the effectiveness of soil conservation measures for sustainable watershed management and crop production using fallout radionuclides" (D1.50.08), organized and funded by the International Atomic Energy Agency through the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. The project brought together nineteen participants, from Australia, Austria, Brazil, Canada, Chile, China, Japan, Morocco, Pakistan, Poland, Romania, Russian Federation, Turkey, United Kingdom, United States of America and Vietnam, involved in the use of nuclear techniques and, more particularly, fallout radionuclides (FRN) to assess the relative impacts of different soil conservation measures on soil erosion and land productivity. The overall objective of the CRP was to develop improved land use and management strategies for sustainable watershed management through effective soil erosion control practices, by the use of ¹³?Cs (half-life of 30.2 years), ²¹?Pb(ex) (half-life of 22.3 years) and ?Be (half-life of 53.4 days) for measuring soil erosion over several spatial and temporal scales. The environmental conditions under which the different research teams applied the tools based on the use of fallout radionuclides varied considerably--a variety of climates, soils, topographies and land uses. Nevertheless, the achievements of the CRP, as reflected in this overview paper, demonstrate that fallout radionuclide-based techniques are powerful tools to assess soil erosion/deposition at several spatial and temporal scales in a wide range of environments, and offer potential to monitor soil quality. The success of the CRP has stimulated an interest in many IAEA Member States in the use of these methodologies to identify factors and practices that can enhance sustainable agriculture and minimize land degradation. PMID:22336567

Dercon, G; Mabit, L; Hancock, G; Nguyen, M L; Dornhofer, P; Bacchi, O O S; Benmansour, M; Bernard, C; Froehlich, W; Golosov, V N; Haciyakupoglu, S; Hai, P S; Klik, A; Li, Y; Lobb, D A; Onda, Y; Popa, N; Rafiq, M; Ritchie, J C; Schuller, P; Shakhashiro, A; Wallbrink, P; Walling, D E; Zapata, F; Zhang, X

2012-05-01

20

Robotic weld overlay coatings for erosion control  

NASA Astrophysics Data System (ADS)

Research is being conducted to develop criteria for selecting weld overlay coatings for erosion mitigation in circulated fluidized beds. Twelve weld overlay alloys were deposited on 1018 steel substrates using plasma arc welding. Ten samples from each coating were prepared for erosion testing. All selected coatings were erosion tested at 400C and their erosion resistance and microstructure evaluated. Steady state erosion rates were similar for several weld overlay coatings (Ultimet, Inconel-625, Iron-Aluminide, 316L SS, and High Chromium Cast Iron) and were considerably lower than the remaining coating evaluated. These coatings had different base (Co, Fe, Ni-base). No correlations were found between room temperature microhardness of the weld overlay coatings and their erosion resistance at elevated temperature, although this criteria is often thought to be an indicator of erosion resistance. It was suggested that the coatings that showed similar erosion rates may have similar mechanical properties such as fracture strength, toughness and work hardening rates at this temperature. During the past quarter, Iron-Aluminide, Inconel-625, and 316L SS coatings were selected for more detailed investigations based upon the preliminary erosion test results. Microhardness tests were performed on eroded samples to determine the size of the work hardened zone and change in coatings hardness due to erosion. The work hardened zone was correlated with erosion resistance of the coatings. Additional Iron-Aluminide, Inconel-625, and 316L SS coatings were deposited on 1018 steel substrates.

Levin, B. F.; Dupont, J. N.; Marder, A. R.

1994-01-01

21

Controls of Bedrock Erosion by Granular Flows  

NASA Astrophysics Data System (ADS)

There is mounting evidence that episodic scour by debris flows can be a significant transport and erosional process in high gradient valleys, yet there is not an agreed upon mechanical framework of how debris flows erode these steep bedrock valleys. To understand the evolution of steep topography we must understand the physical processes that control valley incision by debris flows. Field observations in many different settings and rock types indicate an abundance of wear features characteristic of brittle failure due to discrete particle impacts. Further, close inspection of smooth bedrock channels can reveal occasional scratches that indicate wear by sliding debris, a phenomenon also seen in laboratory experiments. With these observations in mind we use discrete element simulations of dry granular flows to investigate interactions between the flow and the subjacent bed. With this type of computer simulation, particle-particle and particle-boundary interactions are modeled explicitly for every particle and boundary in the system. This allows measurement of variables difficult to characterize in experiments and continuum type models. The granular simulations are first validated with comparisons to quantities measurable in analog experiments. We then use the simulations to explore two aspects of granular flow. First, how does the efficiency of impact and abrasion wear of a granular flow change as a function of field-measurable flow characteristics? Second, what aspects of the actual granular mechanics change to make the flow more or less erosive? We hypothesize that changes in granular properties such as distance traveled between impacts, the extent of force networks, contact time distributions, and slide distance will correlate with changes in erosive efficiency of the flow. We track these properties throughout the flow simulation. Using impact energy and particle-bed contact forces as proxies for the erosional potential of the flow the simulations predict how the magnitude of bed erosion should scale with field-measurable properties (e.g. grain size distribution, flow thickness, slope of the bed and bed roughness). These simulations illuminate the link between granular mechanics, scaling behavior, and field-measurable properties, and this in turn provides elements needed to formulate a mechanical theory for impact wear by debris flows.

McCoy, S. W.; Tucker, G. E.

2008-12-01

22

Tehnical Solution for Marine Erosion Control  

Microsoft Academic Search

Al the countries that are conterminous with seas or oceans are confronted with erosion phenomena caused especially by the sea's movement as waves. The Romanian Black Sea shore is no exception. The costal erosion progresses year by year, the sea-fronts collapse over wide areas, the beaches become narrower, while in certain areas they have disappeared all together, and the buildings

Constantin IULIAN

23

Can control of soil erosion mitigate water pollution by sediments?  

PubMed

The detrimental impact of sediment and associated pollutants on water quality is widely acknowledged, with many watercourses in the UK failing to meet the standard of 'good ecological status'. Catchment sediment budgets show that hill slope erosion processes can be significant sources of waterborne sediment, with rates of erosion likely to increase given predicted future weather patterns. However, linking on-site erosion rates with off-site impacts is complicated because of the limited data on soil erosion rates in the UK and the dynamic nature of the source-pathway-receptor continuum over space and time. Even so, soil erosion control measures are designed to reduce sediment production (source) and mobilisation/transport (pathway) on hill slopes, with consequent mitigation of pollution incidents in watercourses (receptors). The purpose of this paper is to review the scientific evidence of the effectiveness of erosion control measures used in the UK to reduce sediment loads of hill slope origin in watercourses. Although over 73 soil erosion mitigation measures have been identified from the literature, empirical data on erosion control effectiveness are limited. Baseline comparisons for the 18 measures where data do exist reveal erosion control effectiveness is highly variable over time and between study locations. Given the limitations of the evidence base in terms of geographical coverage and duration of monitoring, performance of the different measures cannot be extrapolated to other areas. This uncertainty in effectiveness has implications for implementing erosion/sediment risk reduction policies, where quantified targets are stipulated, as is the case in the EU Freshwater Fish and draft Soil Framework Directives. Also, demonstrating technical effectiveness of erosion control measures alone will not encourage uptake by land managers: quantifying the costs and benefits of adopting erosion mitigation is equally important, but these are uncertain and difficult to express in monetary terms. PMID:23815978

Rickson, R J

2014-01-15

24

Weld overlay coatings for erosion control  

SciTech Connect

A literature review was made. In spite of similarities between abrasive wear and solid particle erosion, weld overlay hardfacing alloys that exhibit high abrasion resistance may not necessarily have good erosion resistance. The performance of weld overlay hardfacing alloys in erosive environments has not been studied in detail. It is believed that primary-solidified hard phases such as carbides and intermetallic compounds have a strong influence on erosion resistance of weld overlay hardfacing alloys. However, relationships between size, shape, and volume fraction of hard phases in a hardfacing alloys and erosion resistance were not established. Almost all hardfacing alloys can be separated into two major groups based upon chemical compositions of the primary solidified hard phases: (a) carbide hardening alloys (Co-base/carbide, WC-Co and some Fe base superalloys); and (b) intermetallic hardening alloys (Ni-base alloys, austenitic steels, iron-aluminides).

Levin, B.; DuPont, J.N.; Marder, A.R.

1993-03-03

25

Erosion  

NSDL National Science Digital Library

Soil erosion is a global problem. Each year, erosion costs billions of dollars in loss of land productivity, damage from soil sediment deposition and subsequent restoration costs, and harm to plant, animal, and human health due to air and water pollution. This lesson will consider the impacts of erosion at local, regional, national, and international levels. It will discuss how erosion occurs and the main factors that contribute to erosion. In addition, the different types of water and wind erosion will be discussed.The lesson is written to target educational needs of lower level undergraduate students and is open for use by the public and educational institutions. Depending on the goals/objectives of a course, training, workshop, part or all sections of the lesson could be used.

26

Projected rainfall erosivity changes under climate change from multimodel and multiscenario projections in Northeast China  

NASA Astrophysics Data System (ADS)

SummaryFuture changes in precipitation will induce changes in the erosive power of rainfall and hence changes in soil erosion rates. In this study we calculated downscaled mean annual precipitation and USLE rainfall erosivity ( R) for time periods 2030 through 2059 and 2070 through 2099 in Northeast China using future precipitation predicted from six GCM models under three emissions scenarios. To accomplish this we created a new approach wherein we combined the well evaluated methods developed by Zhang (2005, 2007) for downscaling monthly precipitation products at time scales meaningful for modeling erosion processes, and the validated method developed by Yu (2002, 2003) for using a weather generator (CLIGEN) to generate accurate RUSLE erosivity factors. Changes were compared to 1960 through 1999 conditions. A stochastic weather generator (CLIGEN) calibrated to precipitation for the period 1960 through 1999 was used to temporally downscale the GCM output, from which the future R values were calculated. Our results suggested a general increase in erosivity over the region by the mid-21st century. Changes in rainfall erosivity under the higher greenhouse gas emissions scenarios, A1B and A2, exhibited the greatest projected changes. The results also indicated that changes in total annual rainfall amounts were not uniformly correspondent spatially to changes in erosivity. Multimodel means showed a generally larger increase in the northern portion of the region than that in the southern part. Future rainfall erosivity changes will have important impacts on soil and water resources in Northeastern China .

Zhang, Y.-G.; Nearing, M. A.; Zhang, X.-C.; Xie, Y.; Wei, H.

2010-04-01

27

DEMONSTRATION OF EROSION AND SEDIMENT CONTROL TECHNOLOGY. LAKE TAHOE REGION OF CALIFORNIA  

EPA Science Inventory

A three-year project was conducted by the California State Water Resources Control Board to determine methods of preventing and correcting erosion problems which severely effect the quality of the waters of the State of California. Two-project sites were chosen in the vicinity of...

28

Erosion  

NSDL National Science Digital Library

Students will design and conduct an open-ended investigation using a variety of earth materials to answer a question posed by the teacher: How does the erosion of sand compare with the erosion of gravel? After producing evidence that addresses this question, they will generate their own question that could be answered with further scientific inquiry.

Science, Pals-Performance A.

2012-04-24

29

Bank Erosion Control with Vegetation, San Francisco Bay, California.  

National Technical Information Service (NTIS)

During 1975 to 1978, an intertidal shoreline stabilization study was conducted to determine biological means of controlling erosion. California cordgrass Trin. (Spartina foliosa) and mussels Dillwyn (Ischadium demissum) were used in San Pablo Bay and Sout...

C. L. Newcombe, J. H. Morris, P. L. Knutson, C. S. Gorbics

1979-01-01

30

Controlling template erosion with advanced cleaning methods  

NASA Astrophysics Data System (ADS)

We studied the erosion and feature stability of fused silica patterns under different template cleaning conditions. The conventional SPM cleaning is compared with an advanced non-acid process. Spectroscopic ellipsometry optical critical dimension (SE-OCD) measurements were used to characterize the changes in pattern profile with good sensitivity. This study confirmed the erosion of the silica patterns in the traditional acid-based SPM cleaning mixture (H2SO4+H2O2) at a rate of ~0.1nm per cleaning cycle. The advanced non-acid clean process however only showed CD shift of ~0.01nm per clean. Contamination removal & pattern integrity of sensitive 20nm features under MegaSonic assisted cleaning is also demonstrated.

Singh, SherJang; Yu, Zhaoning; Wähler, Tobias; Kurataka, Nobuo; Gauzner, Gene; Wang, Hongying; Yang, Henry; Hsu, Yautzong; Lee, Kim; Kuo, David; Dress, Peter

2012-03-01

31

Management of Winter Soil Temperatures to Control Streambank Erosion  

E-print Network

. Riparian management should be designed to provide sufficient vegetative cover over the winter to insulateManagement of Winter Soil Temperatures to Control Streambank Erosion CAROLYN BORN! Range, Wildlife and Forestry Department University of Nevada-Reno Reno, Nevada 89512 USA Abstract.-Winter soil temperatures

32

Geologic controls of erosion and sedimentation on Mars  

NASA Technical Reports Server (NTRS)

Because Mars has had a history of diverse erosional and depositional styles, a variety of erosional landforms and sedimentary deposits can be seen on Viking orbiter images. Here we review how geologic processes involving rock, water, and structure have controlled erosion and sedimentation on Mars. Additionally, we review how further studies will help refine our understanding of these processes.

Tanaka, K. L.; Dohm, J. M.; Carr, M. H.

1993-01-01

33

Use of palm-mat geotextiles for rainsplash erosion control  

NASA Astrophysics Data System (ADS)

Soil detachment by raindrop action (rainsplash erosion) is a very important subprocess of erosion by water. It is a particular problem in the UK as most soils are sandy or loamy sand in texture and lands have gentle to medium slope. However, few studies report potential rainsplash erosion control options under field conditions. Hence, the utilization of palm-mat geotextiles as a rainsplash erosion control technique was investigated at Hilton, east Shropshire, U.K. (52°33'5.7? N, 2°19'18.3? W). Geotextile-mats constructed from Borassus aethiopum (Borassus palm of West Africa) and Mauritia flexuosa (Buriti palm of South America) leaves are termed Borassus mats and Buriti mats, respectively. Two-year field experiments were conducted at Hilton to study the effects of emplacing Borassus and Buriti mats on rainsplash erosion of a loamy sand soil. Two sets (12 plots each) of experiments were established to study the effects of these mats on splash height and splash erosion. Splash height needs to be known to assess the transport mechanism of major soil fraction and its constituents on sloping land by rainsplash. In both sets, six randomly-selected plots were covered with mats, and the rest were bare. Results (during 22/01/2007?23/01/2009; total precipitation = 1731.5 mm) show that Borassus mat-covered plots had ˜ 89% ( P < 0.001) less total splash erosion (2.97 kg m - 2 ) than bare plots (27.02 kg m - 2 ). Comparatively, mean splash height from Borassus mat-covered plots (0.12 m) was significantly ( P < 0.001) less than the bare plots, by ˜ 54%. However, Buriti mat-cover on bare plots had no significant ( P > 0.05) effect in rainsplash erosion control during that period, although plots with Buriti mats significantly ( P < 0.05) decreased splash height (by ˜ 18%) compared with bare plots (0.26 m). Buriti mats, probably due to their ˜ 43, 62 and 50% lower cover percentage (44%), mass per unit area (413 g - 2 ) and thickness (10 mm), respectively, compared with Borassus mats, were not effective in rainsplash erosion control. Both mats did not significantly ( P > 0.05) improve selected soil properties (i.e., soil organic matter, particle size distribution, aggregate stability and total soil carbon) as soil organic matter (SOM) input from mat-decomposition was much less than total SOM content. However, the changes in fine and medium sand contents (after 2 years) in the Borassus covered plots were significantly ( P < 0.05; n = 6) related to the total rainsplash erosion during 2007?2009. Emplacement of Borassus and Buriti mats on bare soils did not decrease SOM contents after 2 years, indicating that improvements in some soil properties might occur over longer durations. After ˜ 10 months, Buriti mats lost ˜ 70% of their initial weight ( P < 0.001) and their initial cover percentage ( C, %) decreased drastically ( P < 0.05); whereas, Borassus mats maintained similar C to the initial condition, although mass per unit area decreased by ˜ 20% ( P < 0.05). Moreover, the functional longevity of Borassus mats was ˜ 2 years against only 1 year for Buriti mats. Hence, use of Borassus mats is highly effective for rainsplash erosion control in the UK.

Bhattacharyya, R.; Fullen, M. A.; Davies, K.; Booth, C. A.

2010-07-01

34

A. PROJECT SUMMARY. EROSION BENEATH THE LAURENTIDE ICE SHEET, AND ITS ROLE IN  

E-print Network

A-1 A. PROJECT SUMMARY. EROSION BENEATH THE LAURENTIDE ICE SHEET, AND ITS ROLE IN PLEISTOCENE ICE of erosion by the Laurentide ice sheet, using the cosmogenic isotopes 10 Be and 26 Al. First, we will date and deposited by the Laurentide ice sheet throughout the Pleistocene, we will track the removal of pre

Stone, John

35

Using Compost for Erosion Control and Revegetation  

E-print Network

waterway. 3 The Texas Department of Transportation (TxDOT) has used composted dairy manure, feedlot manure, chicken litter, cotton gin burs, yard trimmings, and municipal biosolids as compost blankets for hydroseeding road rights-of-way to control soil... Size 95% passing 5 /8? sieve, 70% passing 3 /8? sieve with TMECC Method 02.02-B Heavy Metals Following pass in accordance with TMECC Method 04.06: Arsenic (As), Cadmium (Cd), Copper (Cu), Lead (Pb), Mercury (Hg), Molybdenum (Mo), Nickel (Ni...

Mukhtar, Saqib

2005-08-08

36

Aging effects of environmental factors on rolled erosion control products  

E-print Network

and channel erosion is initiated, the process is self sustaining and the runoff continues to erode and carry soil unless stopped by human intervention. Eroded sediments are also efficient carriers of contaminants such as pesticides and heavy metals which... control materials such as organic ones, usually natural fibers like jute, coir, straw and wood fibers, as explained in natural materials section below. 2. Artificial/synthetic mats: non-degradable synthetic mats made up of fibers consisting of polymer...

Khanna, Sumee

2007-04-25

37

Erosion control and watershed management by Spacelab photography  

NASA Astrophysics Data System (ADS)

The interpretability of false color Spacelab photographs for erosion control and water shed management was assessed using photos taken over Nepal and the Mount Everest Massif. The thematic interpretation was done by a geologist working in this region. Scale limitations, image reproduction, and filtering of the photographs are discussed. Results show that much information can be extracted using relatively simple means. Color infrared photography must be used since panchromatic imagery does not show enough detail.

Koelbl, O.; Depury, P.

1985-04-01

38

Effectiveness of coir-based rolled erosion control systems in reducing sediment transport from hillslopes  

Microsoft Academic Search

Accelerated soil erosion is ubiquitous on human-modified hillslopes. A variety of erosion control products have been developed to reduce on-site soil resource degradation, and off-site transport of sediment and sediment-associated contaminants to receiving water bodies. However, limited quantitative data are available to assess erosion reduction effectiveness, and to establish the salient properties of the erosion control products. A replicated field-based

Ross A. Sutherland; Alan D. Ziegler

2007-01-01

39

Contaminant and Erosion Control BaselineContaminant and Erosion Control Baseline Database for the Puerto MosquitoDatabase for the Puerto Mosquito  

E-print Network

Contaminant and Erosion Control BaselineContaminant and Erosion Control Baseline Database with the geology of the areas could explain the sedimentation trends found during this study. A baseline database for the Puerto MosquitoDatabase for the Puerto Mosquito Watershed InWatershed In ViequesVieques, Puerto Rico

Gilbes, Fernando

40

Erosion control at construction sites on red clay soils  

NASA Astrophysics Data System (ADS)

Five single-treatment methods used to stabilize seeded areas at urban and highway construction sites (asphalt-tacked straw, jute netting, mulch blanket, wood chips, excelsior blanket) were tested for their ability to control erosion of red clay soils by comparisons with exposed sites and multiple treatments. Sediment in runoff from experimental plots was characterized during low and high intensity precipitation from natural rainfall episodes during April, May, and June. Reductions in the total sediment concentration of runoff ranged from 28 percent (asphalt-tacked straw, 50 percent slope) to 90 percent (multiple treatments, 40 percent slope), with ?85 percent of the eroded material composed of particles <0.04 mm in diameter. Larger size fractions were effectively reduced by all treatments tested regardless of slope (?70 percent decrease). Established grass cover exceeded 90 percent on all plots after 60 days, but sediment release remained similar, attributable to high intensity rainfall, poor establishment of root systems, and piping on plots treated with tacked straw or jute netting. Results indicate that current stabilization methods shift sediment compostion toward a smaller particle size, causing single treatments to be minimally effective for controlling erosion of the major component of red clay soils. Because small particles have the greatest direct effect on aquatic biota, certain impacts of sedimentation may not be measurably lessened by single treatments in regions where red clays predominate even though the total sediment load is reduced by as much as 75 percent. Clearly, a multiple-treatment approach offers significantly greater control of erosion on red clay soils, however, current economic and construction policy represents a substantial deterrent to implementation.

Lemly, A. Dennis

1982-07-01

41

Evaluation of Erosion Control Products With and Without Added Polyacrylamide  

NASA Astrophysics Data System (ADS)

Polyacrylamide (PAM) has been demonstrated to greatly reduce erosion in furrow irrigation, but much less is known about its effectiveness on the much steeper slopes typical of construction sites. The purpose of this study was to determine if anionic PAM would enhance erosion control either alone on bare soil or in combination with four types of ground covers commonly used for grass establishment: straw, straw erosion control blanket (ECB), wood fiber, and mechanically bonded fiber matrix (MBFM). Tests were conducted under natural rainfall and vegetation on a 4 percent slope (bare soil, straw, ECB, and MBFM) or using a rainfall simulator (bare soil, straw, wood fiber, MBFM) on either 10 percent or 20 percent slope on three different soil substrates. All ground cover treatments were evaluated with and without PAM applied in solution at 19 kg/ha. The straw, ECB, and MBFM significantly reduced runoff volume, average turbidity, and total sediment lost over five rainfall events on the vegetated plots. The addition of PAM to ground covers only occasionally had significant effects on runoff parameters but did significantly increase vegetative coverage overall. The rainfall simulator tests produced similar results after four events, with the straw, wood fiber, and MBFM all having significantly lower turbidity than the bare soil. The PAM significantly reduced turbidity for both the first and second events but did not consistently improve runoff quality after multiple rainfall events for any ground cover-soil combinations tested. Separate tests of PAM applied before or after straw did not indicate a clear advantage of either approach, but runoff turbidity was often significantly reduced with PAM, especially at the 20 percent slope. Turbidity reductions were attributed to flocculation of eroded sediment.

McLaughlin, Richard A.; Brown, Tabitha T.

2006-06-01

42

Controls of dust emission fluxes and wind erosion threshold on a wet playa  

NASA Astrophysics Data System (ADS)

The control of dust emissions from crusted surfaces is both highly variable and difficult to measure directly. Seasonal changes in moisture availability, temperature, evaporation, surface roughness, and sediment supply result in a highly complex surface condition that remains to be fully described in the context of wind erosion potential. A highly intensive project on Sua Pan, Botswana using the PI-SWERL (portable wind tunnel) combined with surface measurements of crust and soil properties has led to a new understanding of the controls on wind erosion from these surfaces. The PI-SWERL is a highly portable wind tunnel that applies a wind shear to the surface using a motor-controlled rotating annular blade and measures resulting dust emissions with a DustTrak dust monitor. We undertook a sequence of tests with the PI-SWERL to obtain both the wind erosion threshold (using a slowly increasing shear velocity) and a dust emission flux (using a constant shear velocity) across a 12 km by 12 km grid across the pan surface. A total of just under 1000 wind tunnel tests and 2000 correlated measurements of a variety of surface properties including crust thickness, surface and subsurface soil moisture, shearing strength (shear vane), normal stress resistance (penetrometer), and surface roughness were conducted in August 2011. These results show that wind erosion potential is best described by measurements of normal stress resistance rather than shearing strength at low dust emission fluxes, but despite their frequent use in wind erosion studies of crusted surfaces neither metric provided a good explanation of higher dust emission fluxes. Surface soil moisture explained the most variation in both dust emissions and wind erosion threshold although much variation remains unexplained. Our results suggested that combining measurements of surface roughness, soil moisture, and crust thickness provided a reasonable explanation of wind erosion potential on the salt pan surface. As pan surfaces can exhibit a range of aerodynamic roughness lengths over three orders of magnitude the small-scale partition of wind stress could be considered. Surface soil moisture also had a very large range in which a relatively sharp threshold was found to increase dust emissions when combined with other surface factors. Although the role of surface moisture in dust emissions is understood it remains a very difficult (yet critical) parameter to measure and a call for more precise estimations of this metric is highly encouraged.

Wiggs, G.; King, J.; Thomas, D. S.; Washington, R.

2012-12-01

43

Field studies of beach cones as coastal erosion control/reversal devices for areas with significant oil and gas activities. Technical progress report, April--June 1992 and Project status report, June 1992  

SciTech Connect

A field demonstration/study of a novel shoreline erosion protection device called beach cones is planned. These patented, fiberglass- reinforced concreted devices are to be deployed in a number of geometric patterns at seven location in the Bastian Bay area of Western Plaquemines Parish. The purpose of the work described in this report was to evaluate the proposed study`s impact on living and non-living shellfish resources within each of the project`s seven separate Study Areas. Major accomplishments for this reporting period were as follows: aerial photographs of the experimental sites were taken; all permit applications were filed; information was submitted for the Environmental Report; several reconnaissance trips to the experimental sites were made; meetings were held among all participating organizations to further plan the research; permit was obtained from the US Army Corps of Engineers; test sites were surveyed by the Xavier University contingent; survey data were taken at all sites; the Oyster Assessment was completed; permit was obtained from the State of Louisiana Department of Natural Resources; and initial survey data were finalized at all sites.

Not Available

1992-07-17

44

Backshore sill beach and dune erosion control system  

SciTech Connect

A backshore sill beach and dune erosion control system is described comprising: a supporting protective apron formed of weather and water resistant cloth. The apron includes a flat base portion and an angularly sloped portion extending seaward of the base portion, a toe scour anchor tube connected to the seaward end of the apron sloped portion, and longitudinal sand-filled geotextile containers placed upon the apron base portion each extending longitudinally shore parallel to the incoming surf. The sand-filled geotextile containers are specifically placed upon the beach in a pyramidal longitudinally extending shore parallel relation to an area being protected whereby wave action impacts upon relatively soft surfaces of the containers and is dissipated before normally impacting surfaces that would otherwise be eroded.

Sample, J.W.

1988-03-08

45

Erosion calderas: origins, processes, structural and climatic control  

Microsoft Academic Search

The origin and development of erosion-modified, erosion-transformed, and erosion-induced depressions in volcanic terrains\\u000a are reviewed and systematized. A proposed classification, addressing terminology issues, considers structural, geomorphic,\\u000a and climatic factors that contribute to the topographic modification of summit or flank depressions on volcanoes. Breaching\\u000a of a closed crater or caldera generated by volcanic or non-volcanic processes results in an outlet valley.

Dávid Karátson; Jean-Claude Thouret; Ichio Moriya; Alejandro Lomoschitz

1999-01-01

46

Structural practices for controlling sediment transport from erosion  

NASA Astrophysics Data System (ADS)

Erosion on agricultural fields in the hilly regions of Flanders, Belgium has been recognized as an important economical and ecological problem that requires effective control measures. This has led to the implementation of on-site and off-site measures such as reduced tillage and the installation of grass buffers trips, and dams made of vegetative materials. Dams made out of coir (coconut) and wood chips were evaluated on three different levels of complexity. Under laboratory conditions, one meter long dams were submitted to two different discharges and three sediment concentrations under two different slopes, to assess the sediment delivery ratios under variable conditions. At the field scale, discharge and sediment concentrations were monitored under natural rainfall conditions on six 3 m wide plots, of which three were equipped with coir dams, while the other three served as control plots. The same plots were also used for rainfall simulations, which allowed controlling sediment delivery boundary conditions more precisely. Results show a clear advantage of these dams to reduce discharge by minimum 49% under both field and laboratory conditions. Sediment delivery ratios (SDR) were very small under laboratory and field rainfall simulations (4-9% and 2% respectively), while larger SDRs were observed under natural conditions (43%), probably due to the small sediment concentrations (1-5 g l-1) observed and as such a larger influence of boundary effects. Also a clear enrichment of larger sand particles (+167%) could be observed behind the dams, showing a significant selective filtering effect.

Gabriels, Donald; Verbist, Koen; Van de Linden, Bruno

2013-04-01

47

Robotic weld overlay coatings for erosion control. Quarterly technical progress report, January 1994--March 1994  

SciTech Connect

The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterwalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in circulated fluidized beds.

Levin, B.F.; Dupont, J.N.; Marder, A.R.

1994-04-21

48

Robotic weld overlay coatings for erosion control. Quarterly technical progress report, January 1993--March 1993  

SciTech Connect

Twelve weld overlay hardfacing alloys have been selected for preliminary erosion testing based on a literature review These alloys have been separated into three major groups: (1) Cobalt containing alloys, (2) Nickel-base alloys, (3) Iron base alloys. These alloys are being applied to carbon steel substrates and will undergo preliminary erosion testing to identify candidates weld overlay alloys for erosion control in CFB boilers. The candidate alloys selected from the preliminary erosion tests will then undergo more detailed evaluations in future research.

Levin, B.F.; Dupont, J.N.; Marder, A.R.

1993-04-18

49

7 CFR 3201.68 - Erosion control materials.  

...demolition, or other sites to prevent wind or water erosion of loose earth surfaces, which may be combined with seed and/or fertilizer to promote growth. (b) Minimum biobased content. The Federal preferred procurement product must have a...

2014-01-01

50

Geotubes for erosion control along the Texas Gulf Intracoastal Waterway  

E-print Network

directly from a hydraulic dredge with dredged material. Geotubes placed along the GIWW are designed to withstand the pressures of filling, provide sufficient permeability, contain the dredged material, and resist erosion once in place. They are designed...

Cobb, David Earl

2012-06-07

51

76 FR 68745 - Notice of Intent To Update the Upland Erosion Control and Revegetation and Maintenance Plan and...  

Federal Register 2010, 2011, 2012, 2013

...Erosion Control and Revegetation and Maintenance Plan and the Wetland and Waterbody Construction and Mitigation Procedures and Request...Erosion Control, Revegetation and Maintenance Plan (Plan) and Wetland and Waterbody Construction and Mitigation Procedures...

2011-11-07

52

THE SOUTHWEST WASHINGTON COASTAL EROSION STUDY: A SCIENTIFIC RESEARCH PROJECT TO ADDRESS MANAGEMENT-SCALE OBJECTIVES  

Microsoft Academic Search

The Southwest Washington Coastal Erosion Study is a five-year, multi-disciplinary research project designed to build a knowledge foundation as a sound basis for addressing coastal management objectives. The purpose of the Study is to gain an understanding of a regional coastal sediment system, the Columbia River littoral cell, in order to support local, state, and federal decision-making in land-use planning,

George M. Kaminsky; Guy Gelfenbaum

53

Quantitative evaluation of strategies for erosion control on a railway embankment batter  

NASA Astrophysics Data System (ADS)

Strategies for erosion control on a railway embankment batter (side slope) are quantitatively evaluated in this paper. The strategies were centred on control (do nothing treatment), grass seeding, gypsum application, jute mat (an erosion control blanket) placement and planting hedgerows of Monto vetiver grass. Rainfall and runoff were monitored at 1 min intervals on 10 m wide embankment batter plots during 1998 and 1999. Total bedload and suspended sediment eroded from the plots were also measured but only for a group of storm events within sampling intervals. It has been demonstrated that vetiver grass is not cost-effective in controlling erosion on railway batters within Central Queensland region. Seeding alone could cause 60% reduction in the erosion rate compared with the control treatment. Applying gypsum to the calcium-deficient soil before seeding yielded an additional 25% reduction in the erosion rate. This is the result, primarily, of 100% grass cover establishment within seven months of sowing. Therefore, for railway embankment batter erosion control, the emphasis needs to be on rapid establishment of 100% grass cover. For rapid establishment of grass cover, irrigation is necessary during the initial stages of growth as the rainfall is unpredictable and the potential evaporation exceeds rainfall in the study region. The risk of seeds and fertilizers being washed out by short-duration and high-intensity rainfall events during the establishment phase may be reduced by the use of erosion control blankets on sections of the batters. Accidental burning of grasses on some plots caused serious erosion problems, resulting in very slow recovery of grass growth. It is therefore recommended that controlled burning of grasses on railway batters should be avoided to protect batters from being exposed to severe erosion.

Gyasi-Agyei, Y.; Sibley, J.; Ashwath, N.

2001-12-01

54

Control of water erosion and sediment in open cut coal mines in tropical areas  

SciTech Connect

The purpose is to reduce the environmental impacts from open cut mining in tropical areas, such as Indonesia and Vietnam. Research conducted on methods for the control of water erosion and sediment from open cut coal mines is described. Data were collected on climate and weathering in tropical areas, mechanism of water erosion and sedimentation, characteristics of rocks in coal measures under wet conditions, water management at pits and haul roads and ramps, and construction of waste dumps and water management. The results will be applied to the optimum control and management of erosion and sediments in open cut mining. 6 refs., 8 figs.

Ueda, T.; Nugraha, C.; Matsui, K.; Shimada, H.; Ichinose, M.; Gottfried, J. [Kyushu University, Fukuoka (Japan). Department of Earth Resources Engineering

2005-07-01

55

Effect of nonerodible grains on wind erosion control  

Microsoft Academic Search

A simple drag partition scheme for rough surfaces of various roughness densities is presented to explain the effect of roughness density on apparent threshold friction velocity, the validity of which is confirmed by comparison with measured data sets. Based on this drag partition scheme, we assume that the presence of nonerodible rough grains affects the wind erosion of an erodible

Qingsong Mu

2010-01-01

56

Gullying and erosion control 507 Copyright 2006 John Wiley & Sons, Ltd. Earth Surf. Process. Landforms 31, 507525 (2006)  

E-print Network

Gullying and erosion control 507 Copyright © 2006 John Wiley & Sons, Ltd. Earth Surf. Process Gullying and erosion control at archaeological sites in Grand Canyon, Arizona Joel L. Pederson1 *, Paul A, USA Abstract Gully erosion of cultural sites in Grand Canyon National Park is an urgent management

Pederson, Joel L.

57

Stubble Mulch Management for Water Conservation and Erosion Control on Hardlands of the Southern Great Plains.  

E-print Network

LIBRARY A; & k!. COLl EGF f STUBBLE MULCH MANAGEMENT for Water Conservation and Erosion Control on Hardlands of the Southern Great Plains in cooperation with the UNITED STATES DEPARTMENT OF AGRICULTURE [Blank Page in Original Bulletin... STUBBLE MULCH MANAGEMENT For Water Conservation and Erosion Control Hardlands the Southern Great Plains CHARLES J. WHITFIELD, C. E. VAN DOREN and WENDELL JOHNSON* L EARNING to farm the heavy soils of the Southern Great Plains successfully has been...

Johnson, Wendell C. (Wendell Clifford); Van Doren, C. E.; Whitfield, Charles J. (Charles James)

1949-01-01

58

Model based optimization of wind erosion control by tree shelterbelt for suitable land management  

NASA Astrophysics Data System (ADS)

The degradation of soil by wind erosion causes huge problem in many parts of the world. The wind erodes the upper, nutrition rich part of the soil, therefore erosion causes soil productivity loss. The length of tree shelterbelts was significantly reduced by the collectivisation (1960-1989) and the wind erosion affected areas expanded in Hungary. The tree shelterbelt is more than just a tool of wind erosion control; by good planning it can increase the yield. The tree shelterbelt reduces the wind speed and changes the microclimate providing better condition to plant growth. The aim of our work is to estimate wind erosion risk and to find the way to reduce it by tree shelterbelts. A GIS based model was created to calculate the risk and the optimal windbreak position was defined to reduce the wind erosion risk to the minimum. The model is based on the DIN 19706 (Ermitlung der Erosiongefährdung von Böden durch Wind, Estimation of Wind Erosion Risk) German standard. The model uses five input data: structure and carbon content of soil, average yearly wind speed at 10 meters height, the cultivated plants and the height and position of windbreak. The study field (16km2) was chosen near Szeged (SE Hungary). In our investigation, the cultivated plant species and the position and height of windbreaks were modified. Different scenarios were made using the data of the land management in the last few years. The best case scenario (zero wind erosion) and the worst case scenario (with no tree shelter belt and the worst land use) were made to find the optimal windbreak position. Finally, the research proved that the tree shelterbelts can provide proper protection against wind erosion, but for optimal land management the cultivated plant types should also controlled. As a result of the research, a land management plan was defined to reduce the wind erosion risk on the study field, which contains the positions of new tree shelterbelts planting and the optimal cultivation.

Bartus, M.; Farsang, A.; Szatmári, J.; Barta, K.

2012-04-01

59

Erosion Basics  

NSDL National Science Digital Library

This homepage of Dr. Richard A. McLaughlin at North Carolina State University includes a four-part tutorial about soil erosion and mitigation. Slide presentations include an introduction to the factors that lead to soil erosion, a general discussion of soil characteristics and susceptibility to erosion, an overview of the formation of rills and gullies, and some examples of sediment transport dynamics and erosion reduction techniques. The site also features short videos that show tests of erosion control methods in an artificial environment.

Mclaughlin, Richard A.; University, North C.

60

Tectonic control on 10Be-derived erosion rates in the Garhwal Himalaya, India  

NASA Astrophysics Data System (ADS)

Erosion in the Himalaya is responsible for one of the greatest mass redistributions on Earth and has fueled models of feedback loops between climate and tectonics. Although the general trends of erosion across the Himalaya are reasonably well known, the relative importance of factors controlling erosion is less well constrained. Here we present 25 10Be-derived catchment-averaged erosion rates from the Yamuna catchment in the Garhwal Himalaya, northern India. Tributary erosion rates range between ~0.1 and 0.5 mm yr-1 in the Lesser Himalaya and ~1 and 2 mm yr-1 in the High Himalaya, despite uniform hillslope angles. The erosion-rate data correlate with catchment-averaged values of 5 km radius relief, channel steepness indices, and specific stream power but to varying degrees of nonlinearity. Similar nonlinear relationships and coefficients of determination suggest that topographic steepness is the major control on the spatial variability of erosion and that twofold to threefold differences in annual runoff are of minor importance in this area. Instead, the spatial distribution of erosion in the study area is consistent with a tectonic model in which the rock uplift pattern is largely controlled by the shortening rate and the geometry of the Main Himalayan Thrust fault (MHT). Our data support a shallow dip of the MHT underneath the Lesser Himalaya, followed by a midcrustal ramp underneath the High Himalaya, as indicated by geophysical data. Finally, analysis of sample results from larger main stem rivers indicates significant variability of 10Be-derived erosion rates, possibly related to nonproportional sediment supply from different tributaries and incomplete mixing in main stem channels.

Scherler, Dirk; Bookhagen, Bodo; Strecker, Manfred R.

2014-02-01

61

Cover crops effectiveness for soil erosion control in Sicilian vineyard  

NASA Astrophysics Data System (ADS)

In vineyards, which are very common in Mediterranean area, cover crops are becoming increasingly used to reduce soil erosion. Cover crops reduce runoff by increasing infiltration and increasing roughness and then reducing the ovelandflow velocity. The aim of the present study was to quantify soil and water losses under different soil managements systems on vineyards. The study site was a Sauvignon blanc winegrape vineyard located in Southwestern Sicily. Vineyards were managed both traditionally (conventional tillage) and alternative management using cover crops: 1) Vicia faba ; 2) Vicia faba and Vicia sativa; 3) Trifolium subterraneum, Lolium perenne, Festuca rubra; 4)Trifolium subterraneum, Festuca rubra and Festuca ovina, 5) Triticum durum, 6) Triticum durum and Vicia sativa. To monitor water and sediment yield, a Gerlach trough was installed at each treatment on the vineyard inter-row, with the row vineyard used as a border (topographical border). Runoff was measured after each rainfall event (raingauge 0.2 mm accuracy) from November 2005 to April 2007. And sediments were measured after desiccation. The results show that runoff and erosion were reduced considerably under the treatments with Trifolium subterraneum, Lolium perenne, Festuca rubra and Trifolium subterraneum, Festuca rubra and Festuca ovina (treatments 3 and 4). The soil losses were reduced by 73% under treatment 4 compared to the tillage plot. Conventional tillage and alternative management using Vicia faba cover crop (treatment 1) result the most ineffective treatment to soil erosion. These results show that the use of a cover crop can be a simple soil and water conservation practice in Sicilian vineyards. Key words: soil erosion, cover crops, vineyard, Mediterranean area.

Gristina, L.; Novara, A.; Saladino, S.; Santoro, A.

2009-04-01

62

Reflectance loss of prospective solar concentrator mirrors in erosive environments. The Crosbyton Solar Power Project  

SciTech Connect

The problem addressed in this phase of the Crosbyton Solar Power Project was that of the effect of weathering of solar concentrator mirrors proposed for use in the fixed-mirror, distributed-focus (solar bowl) system with particular emphasis on erosion due to exposure during dust storms. The specific objectives of this research were to evaluate the mirrors with respect to initial reflectance, loss of reflectance due to dust storms and other outdoor exposure phenomena, and dimensional stability; and to develop a rapid technique for the simulation of dust storms so that a model for such reflectance loss as a function of exposure could be developed.

Bethea, R.M.; Barringer, M.T.; Chin, S.; Collier, E.G.; Cooper, A.M.; Reichert, J.D. Jr.; Williams, P.F.

1986-01-01

63

A field experiment on the controls of sediment transport on bedrock erosion  

NASA Astrophysics Data System (ADS)

The earth`s surface is naturally shaped by interactions of physical and chemical processes. In mountainous regions with steep topography river incision fundamentally controls the geomorphic evolution of the whole landscape. There, erosion of exposed bedrock sections by fluvial sediment transport is an important mechanism forming mountain river channels. The links between bedload transport and bedrock erosion has been firmly established using laboratory experiments. However, there are only few field datasets linking discharge, sediment transport, impact energy and erosion that can be used for process understanding and model evaluation. To fill this gap, a new measuring setup has been commissioned to raise an appropriate simultaneous dataset of hydraulics, sediment transport and bedrock erosion at high temporal and spatial resolution. Two natural stone slabs were installed flush with the streambed of the Erlenbach, a gauged stream in the Swiss Pre-Alps. They are mounted upon force sensors recording vertical pressure und downstream shear caused by passing sediment particles. The sediment transport rates can be assessed using geophone plates and an automated moving basket system taking short-term sediment samples. These devices are located directly downstream of the stone slabs. Bedrock erosion rates are measured continuously with erosion sensors at sub-millimeter accuracy at three points on each slab. In addition, the whole slab topography is surveyed with photogrammetry and a structured-light 3D scanner after individual flood events. Since the installation in 2011, slab bedrock erosion has been observed during several transport events. We discuss the relation between hydraulics, bedload transport, resulting pressure forces on the stone slabs and erosion rates. The aim of the study is the derivation of an empirical process law for fluvial bedrock erosion driven by moving sediment particles.

Beer, A. R.; Turowski, J. M.; Fritschi, B.; Rieke-Zapp, D.; Campana, L.; Lavé, J.

2012-12-01

64

The contribution of mulches to control high soil erosion rates in vineyards in Eastern Spain  

NASA Astrophysics Data System (ADS)

Soil erosion take place in degraded ecosystem where the lack of vegetation, drought, erodible parent material and deforestation take place (Borelli et al., 2013; Haregeweyn et al., 2013; Zhao et al., 2013). Agriculture management developed new landscapes (Ore and Bruins, 2012) and use to trigger non-sustainable soil erosion rates (Zema et al., 2012). High erosion rates were measured in agriculture land (Cerdà et al., 2009), but it is also possible to develop managements that will control the soil and water losses, such as organic amendments (Marqués et al., 2005), plant cover (Marqués et al., 2007) and geotextiles (Giménez Morera et al., 2010). The most successful management to restore the structural stability and the biological activity of the agriculture soil has been the organic mulches (García Orenes et al; 2009; 2010; 2012). The straw mulch is also very successful on bare fire affected soil (Robichaud et al., 2013a; 2013b), which also contributes to a more stable soil moisture content (García-Moreno et al., 2013). The objective of this research is to determine the impact of two mulches: wheat straw and chipped branches, on the soil erosion rates in a rainfed vineyard in Eastern Spain. The research site is located in the Les Alcusses Valley within the Moixent municipality. The Mean annual temperature is 13 ºC, and the mean annual rainfall 455 mm. Soil are sandy loam, and are developed at the foot-slope of a Cretaceous limestone range, the Serra Grossa range. The soils use to be ploughed and the features of soil erosion are found after each thunderstorm. Rills are removed by ploughing. Thirty rainfall simulation experiments were carried out in summer 2011 during the summer drought period. The simulated rainfall lasted during 1 hour at a 45 mmh-1 intensity on 1 m2 plots (Cerdà and Doerr, 2010; Cerdà and Jurgensen 2011). Ten experiments were carried out on the control plots (ploughed), 10 on straw mulch covered plots, and 10 on chipped branches covered soil. The results show that the soil erosion is reduced by 10 on straw mulch covered soils and by 4 on chipped branches covered soil. Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE supported this research. References Borrelli, P., Märker, M., Schütt, B. 2013. Modelling post-tree-haversting soil erosion and sediment deposition potential in the Turano River Basin (Italian Central Apennine). Land Degradation & Development, DOI 10.1002/ldr.2214 Cerdà, A., Flanagan, D.C., le Bissonnais, Y., Boardman, J. 2009. Soil erosion and agriculture Soil and Tillage Research 106, 107-108. DOI: 10.1016/j.still.2009.1 Cerdà, A., Morera, A.G., Bodí, M.B. 2009. Soil and water losses from new citrus orchards growing on sloped soils in the western Mediterranean basin. Earth Surface Processes and Landforms 34, 1822-1830. García-Moreno, J., Gordillo-Rivero, Á.J., Zavala, L.M., Jordán, A., Pereira, P. 2013. Mulch application in fruit orchards increases the persistence of soil water repellency during a 15-years period. Soil and Tillage Research 130, 62-68. García-Orenes, F., Cerdà, A., Mataix-Solera, J., Guerrero, C., Bodí, M.B., Arcenegui, V., Zornoza, R. & Sempere, J.G. 2009. Effects of agricultural management on surface soil properties and soil-water losses in eastern Spain. Soil and Tillage Research 106, 117-123. 10.1016/j.still.2009.06.002 García-Orenes, F., Guerrero, C., Roldán, A.,Mataix-Solera, J., Cerdà, A., Campoy, M., Zornoza, R., Bárcenas, G., Caravaca. F. 2010. Soil microbial biomass and activity under different agricultural management systems in a semiarid Mediterranean agroecosystem. Soil and Tillage Research 109, 110-115. 10.1016/j.still.2010.05.005. García-Orenes, F., Roldán, A., Mataix-Solera, J., Cerdà, A., Campoy, M., Arcenegui, V., Caravaca, F. 2012. Soil structural stability and erosion rates influenced by agricultural management practices in a semi-arid Mediterranean agro-ecosystem. Soil Use and Management 28, 571-579. DOI: 10.1111/j.1475-2743.2012.00451.x Giménez Morera, A., Ruiz Sinoga, J.D. y Cerdà, A.

Cerdà, Artemi; Jordán, Antonio; Zavala, Lorena; José Marqués, María; Novara, Agata

2014-05-01

65

Large-scale performance and design for construction activity erosion control best management practices.  

PubMed

The National Pollutant Discharge Elimination System (NPDES) Phase II requires construction activities to have erosion and sediment control best management practices (BMPs) designed and installed for site storm water management. Although BMPs are specified on storm water pollution prevention plans (SWPPPs) as part of the construction general permit (GP), there is little evidence in the research literature as to how BMPs perform or should be designed. The objectives of this study were to: (i) comparatively evaluate the performance of common construction activity erosion control BMPs under a standardized test method, (ii) evaluate the performance of compost erosion control blanket thickness, (iii) evaluate the performance of compost erosion control blankets (CECBs) on a variety of slope angles, and (iv) determine Universal Soil Loss Equation (USLE) cover management factors (C factors) for these BMPs to assist site designers and engineers. Twenty-three erosion control BMPs were evaluated using American Society of Testing and Materials (ASTM) D-6459, standard test method for determination of ECB performance in protecting hill slopes from rainfall induced erosion, on 4:1 (H:V), 3:1, and 2:1 slopes. Soil loss reduction for treatments exposed to 5 cm of rainfall on a 2:1 slope ranged from-7 to 99%. For rainfall exposure of 10 cm, treatment soil loss reduction ranged from 8 to 99%. The 2.5 and 5 cm CECBs significantly reduced erosion on slopes up to 2:1, while CECBs < 2.5 cm are not recommended on slopes >or= 4:1 when rainfall totals reach 5 cm. Based on the soil loss results, USLE C factors ranged from 0.01 to 0.9. These performance and design criteria should aid site planners and designers in decision-making processes. PMID:19398523

Faucette, L B; Scholl, B; Beighley, R E; Governo, J

2009-01-01

66

Extreme soil erosion rates in citrus slope plantations and control strategies. A literature review  

NASA Astrophysics Data System (ADS)

Soil Erosion is a natural process that shapes the Earth. Due to the impact of agriculture, soil erosion rates increase, landforms show gullies and rills, and soils are depleted. In the Mediterranean, wheat, olive and vineyards were the main agriculture products, but new plantations are being found in sloping terrain due to the drip-irrigation. This new strategy results in the removal of the traditional terraces in order to make suitable for mechanization the agriculture plantation. Citrus is a clear example of the impact of the new chemical agriculture with a high investment in herbicides, pesticides, mechanisation, land levelling and drip computer controlled irrigation systems. The new plantation of citrus orchards is found in the Mediterranean, but also in California, Florida, China and Brazil. Chile, Argentina, and South Africa are other producers that are moving to an industrial production of citrus. This paper shows how the citrus plantations are found as one of the most aggressive plantation due to the increase in soil erosion, and how we can apply successful control strategies. The research into the high erosion rates of citrus orchard built on the slopes are mainly found in China (Wu et al., 1997; Xu et al., 2010; Wang et al., 2011; Wu et al., 2011; Liu et al., 2011; Lü et al., 2011; Xu et al., 2012) and in the Mediterranean (Cerdà and Jurgensen, 2008; 2009; Cerdà et al., 2009a; 2009b; Cerdà et al., 2011; 2012) Most of the research done devoted to the measurements of the soil losses but also some research is done related to the soil properties (Lu et al., 1997; Lü et al., 2012; Xu et al., 2012) and the impact of cover crops to reduce the soil losses (Lavigne et al., 2012; Le Bellec et al., 2012) and the use of residues such as dried citrus peel in order to reduce the soil losses. There are 116 million tonnes of citrus produced yearly, and this affects a large surface of the best land. The citrus orchards are moving from flood irrigated to drip irrigated land, and this contributes to increase the soil losses due to the sloping terrain. Although citrus is a world wide food, and occupy a large surface little is being researched on their impact on soil erosion, land degradation and strategies to control the soil, water and nutrient losses. This paper review the research developed until now and the results show that there is a poor background on this topic. It is necessary to develop research projects to improve the knowledge on the impact of citrus plantations on soil degradation and soil erosion. Another key information from the literature review done, is that most of the research was done in two regions of China and one of the Mediterranean. Definitively, a poor understanding of a huge environmental problem that need more scientific research. Acknowledgements The research projects GL2008-02879/BTE and LEDDRA 243857 supported this research. References Bombino, G., Denisi, P., Fortugno, D., Tamburino, V., Zema, D.A., Zimbone, S.M. 2010. Land spreading of solar-dried citrus peel to control runoff and soil erosion. WIT Transactions on Ecology and the Environment, 140, 145-154. Cerdà, A., Giménez Morera, A., Burguet, M., Arcenegui, V., González Peñaloza, F.A., García-Orenes, F., Pereira, P. 2012. The impact of the farming, abandonment and agricultural intensification on loss of water and soil. The example of the northern slopes of the Serra Grossa, Eastern Spain [El impacto del cultivo, el abandono y la intensificación de la agricultura en la pérdida de agua y suelo. el ejemplo de la vertiente norte de la serra grossa en el este peninsular] Cuadernos de Investigacion Geografica, 38 (1), 75-94. Cerdà, A., Jurgensen, M.F. 2008. The influence of ants on soil and water losses from an orange orchard in eastern Spain. Journal of Applied Entomology, 132 (4), 306-314. Cerdà, A., Jurgensen, M.F. 2011. Ant mounds as a source of sediment on citrus orchard plantations in eastern Spain. A three-scale rainfall simulation approach. Catena, 85 (3), 231-236. Cerdà, A., Jurgensen, M.F., Bodi, M.B. 2009. Effects of ants on

Cerdà, Artemi; Ángel González Peñaloza, Félix; Pereira, Paulo; Reyes Ruiz Gallardo, José; García Orenes, Fuensanta; Burguet, María

2013-04-01

67

The EROSFIRE project - a model-based, decision-support tool for soil erosion hazard assessment following forest wildfires  

Microsoft Academic Search

Since the late summer of 2005, the EROSFIRE project is investigating the hydrological and soil erosion response in recently burnt eucalypt plantations. The study areas are located in the municipalities of Águeda, Albergaria-a-Velha and Sever de Vouga, at reasonably close distances from the project's home base at the University of Aveiro, which has allowed carrying out intensive field campaigns and,

J. Keizer; M. Malvar; J. Nunes; M. Oñate; S. Prats; E. Palacios; S. Menci; C. Coelho; A. García-M; D. Herrera; P. Cascão; C. Martín; A. Lucia; J. Silva; A. Ferreira; C. Magalhães; J. Estrada; V. Pereira; J. Stolte

68

Erosion risk assessment of controlled burning of grasses established on steep slopes  

NASA Astrophysics Data System (ADS)

It is a standard practice to establish grasses on steep slopes (batters) of embankments and cuttings to minimise erosion problems. However, the increase in grass density (high biomass) on the steep slopes poses a greater risk of fire. Controlled burning is a common fuel hazard reduction program employed to minimise the fire risks. The increased risk of erosion on the steep slopes after controlled burning has received little attention if any. This paper assesses the erosion risks associated with controlled burning of grasses established on steep slopes. Grasses, with and without the aid of waste ballast rock mulch, were established on 10 m wide railway embankment batter experiment plots. Two-and-a-half years after the grass establishment, selected plots were controlled burned. Runoff and soil loss from the experimental plots were monitored throughout the 3½-year period of the experiment. After one year the grass cover on the burned plots has hardly exceeded 60%, far below the average pre-burn levels of about 80%. All treatments achieved an incredible soil loss reduction of over 95% (compared with the bare scenario) without controlled burning at the end of the 3½-year period. This percentage value was decreased numerically by 14 where controlled burning was implemented. Compared with the 100% grass cover treatment, runoff rates tripled while erosion rates increased by nine-fold for the waste ballast treatment, and 17-fold for the non-waste ballast treatment, during the first year following controlled burning.

Gyasi-Agyei, Yeboah

2006-02-01

69

Erosion control on a steeply sloped pipeline right-of-way in southwestern Pennsylvania  

SciTech Connect

The results of precipitation on steeply sloped pipeline rights-of-way (ROWs) during the time between ROW rehabilitation and the establishment of a dense, self-sustaining vegetative ground cover can cause locally severe soil erosion. This erosion results in elevated sediment loads in receiving streams and increases the difficulty and costs of ROW maintenance. A field study was completed that compared the environmental effectiveness of nine treatments on a 28% ROW slope in southwestern Pennsylvania. The six erosion-control methods investigated in the study, selected to represent a wide range in material type and installation cost, were (1) heavy application of straw mulch, (2) light application of straw mulch, (3) processed wood fiber, (4) chemical soil binder, (5) paper strips in netting, and (6) light straw mulch with a tacking agent. Each of the test plots also received the basic treatment of limestone, fertilizer, and a seed mixture commonly used to rehabilitate ROWs in the region. Precipitation, runoff volumes, and sediment yields were measured on each of 51 plots for 45 precipitation events during the 18-month study. Vegetation data were collected by the point-intercept method four times during the study to determine the amount of plant cover and species composition. Differences in sediment yield were observed among methods and between ROW location, but plant cover development was not influenced by erosion-control method or location. The relationship between environmental and cost data indicated that, of the six erosion-control methods tested, a light application of straw mulch was the most effective erosion-control treatment. 19 refs., 2 figs., 6 tabs.

Zellmer, S.D.; Edgar, D.E. (Argonne National Lab., IL (USA)); Isaacson, H.R. (Gas Research Inst., Chicago, IL (USA))

1991-01-01

70

Coastal erosion and sea level rise: Implications for ocean beach and San Francisco's westside transport project  

Microsoft Academic Search

One of the consequences of sea level rise resulting from the greenhouse effect is increased coastal erosion. This article discusses a model of erosion that can be used to estimate the response of beaches to sea level rise. The model is applied to Ocean Beach, California, with particular attention to the consequences of accelerated erosion for the San Francisco Westside

Peter J. Wilcoxen

1986-01-01

71

Sediment storage dam: A structural gully erosion control and sediment trapping measure, northern Ethiopia  

NASA Astrophysics Data System (ADS)

Gully erosion is a prime problem in Ethiopia. This study assessed the severity of gully erosion and the role of sediment storage dams (SSD) in restoring gullies and preventing further gully development, its sediment trapping efficacy (STE) and its capacity in converting degraded gully lands to productive land. On average 2.5 m deep, 6.6 m wide and 28.3 m long gullies were formed in Minizr watershed, northwest Ethiopia, in 2013. Concentrated surface runoff, traditional ditches, graded terraces without suitable water ways and road construction are the main causes of such serious gully erosion. Over grazing, tunnel flow and lack of proper immediate gully treatment actions after gully initiation are found to be additional causes of the problem. Gully erosion was also found as the major source of sediment for downstream rivers and water reservoirs. The annual volume of soil eroded from only four gullies was 1941.3 m3. To control gully erosion, SSDs were found to be important physical structures, which can trap significant amount of sediment within gullies and they can convert unproductive gully land to productive agricultural land for fruit and crop production. Eight SSDs trapped about 44*103 m3 of sediment within 2 to 8 years. Two representative SSDs constructed using gabion and stone were tested for their STE. Results showed that their efficacy was 74.1% and 66.4% for the gabion and stone SSDs, respectively. Six of the older SSDs were already full of sediment and created 0.75 ha of productive land within 2 to 8 years. SSDs best fits to treat large size and deep gullies where other gully control measures, check dams, could not function well. To prevent gully formation, controlling its causes that is avoiding traditional ditches, practicing grassed water ways to safely remove runoff water from graded terraces, integrated watershed and road side management practices are important solutions. KEY WORDS: Sediment storage dam, gully erosion, sediment trapping efficacy, productive land, Ethiopia

Mekonnen, Mulatie; Keesstra, Saskia; Baartman, Jantiene; Ritsema, Coen

2014-05-01

72

GEOLOGY, November 2009 975 Climate controls erosion and weathering on soil-mantled land-  

E-print Network

GEOLOGY, November 2009 975 ABSTRACT Climate controls erosion and weathering on soil-mantled land interactions. We quantify denudation, soil and saprolite weathering, and soil transport near the base and crest and weathering processes at these two climatically diverse sites, and our data suggest fundamentally different

Heimsath, Arjun M.

73

Comprehensive Erosion and Sediment Control Training Program for Job Superintendents and Inspectors.  

ERIC Educational Resources Information Center

One of two training program texts built around the Virginia Erosion and Sediment Control Law and Program, this guide presents a program designed to meet the needs of job superintendents and inspectors. (The other guide, containing a program for engineers, architects, and planners, was designed to train professional people who need engineering and…

Porter, Harry L., Jr.

74

Controls of initial topography on temporal and spatial patterns of glacial erosion  

NASA Astrophysics Data System (ADS)

Here we investigate the influence of initial pre-glacial topography on spatial and temporal patterns of glacial erosion using numerical surface process modelling, including a higher order ice sheet model. First, we consider glacier dynamics when simulating glaciation in two real landscapes, representing plateau-type topography (southeast Australia) and characteristic steady-state fluvial topography (southern Taiwan). We find that the different initial landscape configurations result in distinctly different ice configurations and patterns of basal sliding. The sliding patterns are controlled by ice configuration and the resulting basal shear stresses and by the thermal properties at the base of the ice. We then investigate how these characteristic patterns of basal sliding control glacial erosion and long-term landscape evolution using synthetic representations of the two landscapes. The two landscape configurations result in markedly different spatial and temporal patterns of glacial erosion. However, the resulting landscapes may have similar morphology, irrespective of initial landscapes and glacial erosion patterns being significantly different. The numerical experiments also suggest that, in addition to basal temperature, basal shear stress is important in restricting long-term glacial erosion, which is relevant for the preservation of landforms during glaciations. Specifically, pre-glacial landforms may be eroded although they are initially protected by cold-based ice, when the ice configuration promotes significant basal shear stress (glacial erosion) at the edge of a plateau-like landscape. In contrast, pre-glacial landforms may be preserved irrespective of the ice being warm-based, when low gradients in the ice surface act to limit basal shear stress.

Pedersen, Vivi K.; Huismans, Ritske S.; Herman, Frédéric; Egholm, David L.

2014-10-01

75

Project EARTH-12-PPS1: Weathering Rates in the Critical Zone: Soil Erosion, River Chemistry and Climate  

E-print Network

Project EARTH-12-PPS1: Weathering Rates in the Critical Zone: Soil Erosion, River Chemistry and Climate Change Supervisors: Dr. Philip Pogge von Strandmann and Prof. Gideon Henderson Chemical weathering weathering has also been proposed as a geo-engineering method to sequester carbon. It has therefore become

Henderson, Gideon

76

Offshore sand resources for coastal erosion control in Louisiana  

Microsoft Academic Search

An inventory of existing geophysical data supplemented by more than 15,000 km of high-resolution seismic profiles and 400 vibracores collected cooperatively by the Louisiana Geological Survey and US Geological Survey since 1981 indicates that a wide range of aggregate minerals occurs on the continental shelf in a variety of depositional settings. The distribution of these deposits is controlled by the

K. E. Ramsey; S. Penland; R. A. McBride; J. R. Suter; J. Williams

1990-01-01

77

Coastal erosion and sea level rise: implications for Ocean Beach and San Francisco's Westside Transport Project  

SciTech Connect

One of the consequences of sea level rise resulting from the greenhouse effect is increased coastal erosion. This article discusses a model of erosion that can be used to estimate the response of beaches to sea level rise. The model is applied to Ocean Beach, California, with particular attention to the consequences of accelerated erosion for the San Francisco Westside Sewer Transport. Results obtained show that erosion produced by accelerated sea level rise could cause substantial damage to the structure. Large expenditures on beach nourishment will be required to protect the transport and recreational value of the beach. 12 references, 9 figures, 5 tables.

Wilcoxen, P.J.

1986-01-01

78

Project resources planning and control  

NASA Technical Reports Server (NTRS)

This report contains instructional guidelines for the resources planning and control of research and development (R&D) projects managed by NASA's Langley Research Center (LaRC). Although written to serve primarily as a practical guide and reference for those LaRC personnel who perform resources planning, analysis, control, and reporting functions, it should also be meaningful to other NASA personnel who are directly or indirectly involved in or affected by these functions, especially project technical managers whose responsibilities include resources management. Certain sections should help Contractor personnel to better understand what resources information must usually be submitted on LaRC projects and what use is made of such information. The Project Manager of a large R&D project typicaly receives support from an Analyst in the area of resources management. The Analyst provides assistance in four functional areas: Planning, Analysis/Control, Administration, and Reporting. Each of these functions are discussed in detail. Examples of techniques used effectively on LaRC projects have been included where applicable. A considerable amount of information has been included on the use of Performance Measurement (Earned Value) Systems for contract cost control and reporting as little information is currently available on this subject in NASA publications.

Sibbers, C. W.

1984-01-01

79

Offshore sand resources for coastal erosion control in Louisiana  

SciTech Connect

An inventory of existing geophysical data supplemented by more than 15,000 km of high-resolution seismic profiles and 400 vibracores collected cooperatively by the Louisiana Geological Survey and US Geological Survey since 1981 indicates that a wide range of aggregate minerals occurs on the continental shelf in a variety of depositional settings. The distribution of these deposits is controlled by the geometry of the preexisting fluvial and deltaic channel systems and the stratigraphic signature of the Holocene Transgression across these features. The geology of coastal and offshore Louisiana is tied to the depositional history of the Mississippi River. Offshore of the delta plain, five types of aggregate sources can be identified: inner shelf shoals, submerged barrier islands, tidal inlets, distributary channels, and barrier platforms. This paper describes the geology of offshore Louisiana, the available geophysical data sets, and the distribution of aggregate mineral resources. On the continental shelf of the Mississippi River delta plain, two extensive seismic survey grids have been developed by the Louisiana Geological Survey and US Geological Survey. The most prospective resources found are the huge sand bodies of Ship Shoal and associated distributaries, Cat Island Pass tidal channels and associated tidal deltas, and Barataria Pass/Grand Terre tidal channels and associated tidal deltas. East of the mouth of the Mississippi River are the Chandeleur Islands, where LGS identified seven major sand resource targets, truncated barrier-spit and tidal inlet deposits, submerged beach ridges, and distributaries associated with abandoned St. Bernard delta complexes. Abundant sand resources can be found in offshore Louisiana. Many of the sand bodies contain heavy minerals, but their concentration and distribution is unknown. Other potential sand resources not yet adequately explored include Sabine Bank, the Outer Shoal, and the St. Bernard shoal.

Ramsey, K.E.; Penland, S.; McBride, R.A. (Louisiana Geological Survey, Baton Rouge (USA)); Suter, J.R. (Exxon Production Research, Houston, TX (USA)); Williams, J. (Geological Survey, Reston, VA (USA))

1990-09-01

80

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.  

Code of Federal Regulations, 2011 CFR

...erosion, sedimentation, and pollution. 436.574 Section 436...erosion, sedimentation, and pollution. The contracting officer...Erosion, Sedimentation and Pollution, if there is a need for...reforestation, silvicultural, land stabilization, or other...

2011-10-01

81

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.  

Code of Federal Regulations, 2013 CFR

...erosion, sedimentation, and pollution. 436.574 Section 436...erosion, sedimentation, and pollution. The contracting officer...Erosion, Sedimentation and Pollution, if there is a need for...reforestation, silvicultural, land stabilization, or other...

2013-10-01

82

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.  

Code of Federal Regulations, 2010 CFR

...erosion, sedimentation, and pollution. 436.574 Section 436...erosion, sedimentation, and pollution. The contracting officer...Erosion, Sedimentation and Pollution, if there is a need for...reforestation, silvicultural, land stabilization, or other...

2010-10-01

83

48 CFR 436.574 - Control of erosion, sedimentation, and pollution.  

Code of Federal Regulations, 2012 CFR

...erosion, sedimentation, and pollution. 436.574 Section 436...erosion, sedimentation, and pollution. The contracting officer...Erosion, Sedimentation and Pollution, if there is a need for...reforestation, silvicultural, land stabilization, or other...

2012-10-01

84

Assessment of the role of bottomland hardwoods in sediment and erosion control  

USGS Publications Warehouse

Drainage and clearing of bottomland hardwoods have long been recognized by the U.S. Environmental Protection Agency (EPA) and the U.S. Fish and Wildlife Service (Service) as important impacts of Federal water projects in the lower Mississippi River Valley. More recently, the water quality impacts of such projects (e.g., increases in sediments, nutrients, and pesticides) have also become of concern. In 1984, in an effort to better define problems concerning wetland losses and water degradation, EPA initiated a cooperative project with the Western Energy and Land Use Team (now the National Ecology Research Center) of the Service. Three phases of the project were identified: 1. To collect existing literature and data; 2. To select, develop, and test the utility of methods to quantify the relationships between land use, cover types, soils, hydrology, and water quality (as represented by sediment); and 3. To apply selected methodologies to several sites within the Yazoo Basin of Mississippi to determine the, potential effectiveness of various management alternatives to reduce sediment yield, increase sediment deposition, and improve water quality. Methods development focused on linking a simulation of water and sediment movement to a computerized geographic information system. We had several objectives for the resulting model. We desired that it should: 1. Estimate the importance of bottomland and hardwoods as a cover type that performs the functions of erosion and sediment control, 2. Simulate effects of proportions of ' various cover types and their specific spatial configurations, 3. Be applicable to moderately large spatial areas with minimal site-specific calibration, 4. Simulate spatial patterns of sediment loss-gain over time, and 5. Represent both sediment detachment and transport. While it was recognized that impacts and management alternatives could be sorted roughly into landscape measures and channel measures, the decision was made to focus study efforts mainly on landscape measures. Landscape measures include altered drainage and flooding patterns, altered cover types (e.g., conversion of bottomland hardwoods to agricultural crops, reforestation of cropland to bottomland hardwoods, and creation of riparian buffer strips), altered cropping and tillage patterns, altered routing of water, and creation of buffer strips along wetlands and channel margins. Channel measures include vegetative bank stabilization, grade control structures, and regulation of channel water volume and velocity. During the first year of the study, EPA decided not to fund the third phase of the project. This required considerable rescoping of the project with the result that application of the sediment mobilization, routing, and deposition models to various management alternatives and portions of the Yazoo Basin was somewhat restricted. We believe, however, that this report will provide a good understanding of the various modes of sediment mobilization, transport, and deposition within the Yazoo Basin, as well as of the role of bottomland hardwoods. The model developed in this study could be applied to a variety of management or mitigation alternatives prior to implementation to determine their relative effectiveness. Policy, political, and socio-economic consequences of any proposed management/mitigation practice, however, must ultimately be taken into consideration by those charged with management of water resources within the Yazoo Basin before any practice is implemented. This study makes no effort to judge the feasibility of management alternatives in this regard.

Molinas, A.; Auble, Gregor T.; Segelquist, C.A.; Ischinger, Lee S.

1988-01-01

85

Microphonics control for Project X  

SciTech Connect

The proposed multi-MW Project X facility at Fermilab will employ cavities with bandwidths as narrow as 20 Hz. This combination of high RF power with narrow bandwidths combined requires careful attention to detuning control if these cavities are to be operated successfully. Detuning control for Projects X will require a coordinated effort between the groups responsible for various machine subsystems. Considerable progress in this area has been made over the past year. Detuning levels in the Project X cavities, specifically the Low and High {beta} 650 MHz elliptical types, can have a significant impact on the overall cost of the project. The narrow bandwidths, and the high RF Power requirements, and the large number of these cavities mean that careful attention to detuning control will be required if these cavities are to operate successfully. Limiting cavity detuning in Project X will require a coordinated effort between the groups responsible for various subsystems of the planned machine. Considerable progress towards this goal has been made by each of these groups over the past year.

Schappert, W.; Barbanotti, S.; Branlard, J.; Cancelo, G.; Carcagno, R.; Chase, B.; Champion, M.; Gonin, I.; Klebaner, A.; Orris, D.; Pischalnikov, Y.; /Fermilab

2011-03-01

86

Quality Control Mini Culture Project  

E-print Network

IE 361 Quality Control Mini Culture Project "ROBUST ENGINEERING" For: Dr. Vardeman By: Jason main types of quality in a product. These types are (1) customer quality and (2) engineered quality Olberding Brandon Williams Adam Schreiner Jason Paulsen #12;History Behind Robust Engineering (Taguchi

Vardeman, Stephen B.

87

Erosion Coatings for High-Temperature Polymer Composites: A Collaborative Project With Allison Advanced Development Company  

NASA Technical Reports Server (NTRS)

The advantages of replacing metals in aircraft turbine engines with high-temperature polymer matrix composites (PMC's) include weight savings accompanied by strength improvements, reduced part count, and lower manufacturing costs. Successfully integrating high-temperature PMC's into turbine engines requires several long-term characteristics. Resistance to surface erosion is one rarely reported property of PMC's in engine applications because PMC's are generally softer than metals and their erosion resistance suffers. Airflow rates in stationary turbine engine components typically exceed 2.3 kg/sec at elevated temperatures and pressures. In engine applications, as shown in the following photos, the survivability of PMC components is clearly a concern, especially when engine and component life-cycle requirements become longer. Although very few publications regarding the performance of erosion coatings on PMC's are available particularly in high-temperature applications the use of erosion-resistant coatings to significantly reduce wear on metallic substrates is well documented. In this study initiated by the NASA Glenn Research Center at Lewis Field, a low-cost (less than $140/kg) graphite-fiber-reinforced T650 35/PMR 15 sheet-molding compound was investigated with various coatings. This sheet-molding compound has been compression molded into many structurally complicated components, such as shrouds for gas turbine inlet housings and gearboxes. Erosion coatings developed for PMC s in this study consisted of a two-layered system: a bondcoat sprayed onto a cleaned PMC surface, followed by an erosion-resistant, hard topcoat sprayed onto the bondcoat as shown in following photomicrograph. Six erosion coating systems were evaluated for their ability to withstand harsh thermal cycles, erosion resistance (ASTM G76 83 "Standard Practice for Conducting Erosion Tests by Solid Particle Impingement Using Gas Jets") using Al2O3, and adhesion to the graphite fiber polyimide composite (ASTM D 4541 95 "Pull Off Strength of Coatings"). Glenn and Allison Advanced Development Company collaborated to optimize erosion coatings for gas turbine fan and compressor applications. All the coating systems survived aggressive thermal cycling without spalling. During erosion tests (see the final photo), the most promising coating systems tested had Cr3C2-NiCr and WC-Co as the hard topcoats. In all cases, these coating systems performed significantly better than that with a TiN hard topcoat. When material depth (thickness) loss is considered, the Cr3C2-NiCr and WC-Co coating systems provided, on average, an erosion resistance 8.5 times greater than that for the uncoated PMR 15/T650 35 composite. Similarly, Cr3C2-NiCr and WC-Co coating systems adhered to the PMC substrate during tensile tests significantly better than systems containing a TiN topcoat. Differences in topcoats of Cr3C2-NiCr and WC-Co were determined by considering issues such as cost and environmental impact. The preferred erosion-resistant coating system for PMR 15/T650 35 has WC-Co as the hard topcoat. This system provides the following benefits in comparison to the coating system with Cr3C2-NiCr topcoat: lower powder material cost (15 to 20 percent), environmentally friendly materials (Cr3C2-NiCr is hazardous), and higher deposition yield (10 to 15 percent), which results in less waste.

Sutter, James K.

2000-01-01

88

Evaluation of different techniques for erosion control on different roadcuts in its first year of implantation  

NASA Astrophysics Data System (ADS)

Linear infrastructures, such as highways and railways, present a large environmental impact. Among this impact is the effect on landscape and the modification of the hydrological conditions of the area and an increase in erosive processes (Martin et al., 2011). The increase of erosive processes is specially significant in roadbanks, resulting in high maintenance costs as well as security risks for the use of the infrastructure if it is not properly controlled. Among roadbanks, roadcuts are specially challenging areas for erosion control and ecological restoration, due to their usually steep slope gradient and poor conditions for establishment of vegetation. There are several studies in Mediterranean conditions indicating how the combination of semiarid conditions with, sporadic, intense rainfall events makes a successful vegetation development and erosion control in motorway roadbanks extremely difficult (e.g. Andrés and Jorbat, 2000; Bochet and García-Fayos, 2004). This communication presents the results of the first year evaluation (hydrological year 2012-2013) of five different erosion control strategies on six different locations under different materials on roadcuts of motorways or railways in Andalusia during 2012-2013 using natural rainfall and simulated rainfall. The six sites were located on roadcuts between 10 and 20 m long on slope steepness ranging from 40 to 90%, in motorways and railways spread over different materials in Andalusia. Site 1, Huelva was located on consolidated sand material, sites 2, Osuna I, site 3, Osuna II and site 4, Mancha Real, on marls. Sites 5, Guadix, and 6, Fiñana, were located on phyllites, in comparison a harder material. At each site 12 plots (10 m long and 2 m wide) were installed using metal sheets buried 10 cm within the soil with their longest side in the direction of the roadcut maximum slope. Six different treatments were evaluated at each site, two replications each. These treatments were: 1- A control with bare soil, 2-Hydroseeding with a mix of grasses and legumes adapted for Mediterranean conditions, 3- Plantation of Mediterranean shrub species at a 1 plant m-2 density, 4- organic erosion control mat (made of coconut or esparto grass, Stipa tenacissima, fiber) plus hydroseeding. 5- synthetic net mat for erosion control plus hydroseeding. 6- synthetic 3D-net mat for erosion control plus hydroseeding. All the plots had an outlet with routed runoff and sediment to a sediment trap located at the base of the roadcut. The treatments were installed during early fall 2012. Since that date sediments were regularly collected and the evolution of vegetation was monitored. In four of the sites (the other two were vandalized) rainfall simulation experiments using a mesoplot rainfall simulator based on Sumner et al. (1996) were performed in summer 2013. The evaluation of vegetation cover and number of plants made in May, at the end of the rainy season, indicated how the hydroseeding treatments (the three mats plus the hydroseeding without mat) presented a relatively high ground cover (between 25 to 35 %) but with a relatively large standard deviation (around 25%). This variability was clearly related to site features (slope, parent material, and climate conditions for the year) with no clear differences among treatments. The plantation and control treatments presented a much lower ground cover, as expected, ranging, in average, from 5 to 10%. There was a large variability in the pattern of plant distribution within the plots, with site to site differences. So in sites 1, 2 and 5 there was a trend towards increased plant density in the lower area of the plot while in site 3 this trend was reversed and in sites 4 and 6 there was not a clear pattern. Sediment lost during the rainfall period, which ranged from 294 to 778 mm from October 1st to May 31st, presented a large variability among sites with maximum values ranging from 2.5 g m-2 (Fiñana) to 1800 (Mancha real). In all the sites there was a clear difference between the mat treatments which presented very low erosion rates, with

Gomez, Jose Alfonso; Rodríguez, Abraham; Viedma, Antonio; Contreras, Valentin; Vanwalleghem, Tom; Taguas, Encarnación V.; Giráldez, Juan Vicente

2014-05-01

89

Factors controlling gully erosion at different spatial and temporal scales in rangelands of SW Spain  

NASA Astrophysics Data System (ADS)

Gully erosion has been recognized as an important soil degradation process in rangelands of SW Spain. However, little is known about gullying processes at different spatial and temporal scales in these areas. Three different approaches were used in this paper to analyze the factors determining gully erosion intensity and rates at different spatial and temporal scales in rangelands of SW Spain. The first approach was based on the monitoring of a permanent valley bottom gully and continuous measurement of rainfall and discharge during the period 2001-2007 in the Parapuños experimental basin. Parapuños is a small catchment (99.5 ha) representative of dehesa land use, with an undulated topography and Mediterranean climate. Gully erosion volume was obtained by means of 28 fixed cross sections measured with a frequency of 6 months. Discharge and rainfall were monitored using a water depth probe installed in a weir at the outlet of the catchment and 6 tipping bucket rain gauges, respectively. The second approach was based on analyzing the development of the same permanent gully located in Parapuños using six series of aerial ortophotographs for the period 1945-2006. This methodology allowed to relate gully evolution with land use and vegetation cover changes. Finally, a relatively new data mining technique, called Multivariate Adaptive Regression Splines (MARS), was applied to construct a model capable of predicting the location of gullies at the regional scale. A large database composed of 36 independent variables related to topography, lithology, soils, rainfall, land use and vegetation cover was used. This statistical technique allowed to determine the importance of the variables involved. This database was gathered in 46 farms representative of rangelands of SW Spain in Extremadura, covering a surface area of 35,459 ha. Farms were quite diverse although their main characteristics were undulating landforms, acid rocks (schists, greywackes and granites), and Mediterranean climate with Atlantic influences. Results showed that at the catchment scale, and for a short period (1-10 years), rainfall and soil moisture were the most important factors controlling gully erosion rates. In fact, gully erosion was highly related with the rainfall amount (r=0,90), with the number of times event discharge exceeded 1000 cubic meters (r=0,76) and with the number of times peak discharge exceeded 100 l/s (r=0,72). However, when the temporal scale was extended to several decades (from 1945 to 2006), land use and vegetation cover (specially the extension of cultivated area and livestock density) proved to be the most important factors determining the area affected by gullying. With respect to the spatial variation of gullying at the regional scale, the model results indicate lithology as being the most important variable, followed by vegetation structure and summer rainfall. This model was able to explain a large portion of the spatial distribution of gullies at the regional scale. Concluding, at different spatial and temporal scales the importance of factors which determine gully erosion intensity, extension and rates varies notably. At the short-term rainfall and runoff dynamics and the moisture content of the sediments are the dominant factors, whereas at the medium-term land use and vegetation cover become more important. At the regional scale lithology and vegetation turned out to be the dominant factors in determining the location of areas susceptible to gully erosion in rangelands of Extremadura.

Gómez Gutiérrez, Á.; Schnabel, S.; Lavado Contador, J. F.; Pulido Fernández, M.

2009-04-01

90

Gullying and erosion control at archaeological sites in Grand Canyon, Arizona  

Microsoft Academic Search

Gully erosion of cultural sites in Grand Canyon National Park is an urgent management problem that has intensified in recent decades, potentially related to the effects of Glen Canyon Dam. We studied 25 gullies at nine sites in Grand Canyon over the 2002 monsoon- erosion season to better understand the geomorphology of the gully erosion and the effec- tiveness of

Joel L. Pederson; Paul A. Petersen; Jennifer L. Dierker

2006-01-01

91

Soil tillage conservation and its effect on erosion control, water management and carbon sequestration  

NASA Astrophysics Data System (ADS)

The energetic function of the soil expressed through the potential energy accumulated through humus, the biogeochemical function (the circuit of the nutrient elements) are significantly influenced by its hydrophysical function and especially by the state of the bedding- consolidation, soil capacity of retaining an optimal quantity of water, and then its gradual disponibility for plant consumption. The understanding of soil functions and management including nutrient production, stocking, filtering and transforming minerals, water , organic matter , gas circuit and furnishing breeding material, all make the basis of human activity, Earth's past, present and especially future. The minimum tillage soil systems - paraplow, chisel or rotary grape - are polyvalent alternatives for basic preparation, germination bed preparation and sowing, for fields and crops with moderate loose requirements being optimized technologies for: soil natural fertility activation and rationalization, reduction of erosion, increasing the accumulation capacity for water and realization of sowing in the optimal period. By continuously applying for 10 years the minimum tillage system in a crop rotation: corn - soy-bean - wheat - potato / rape, an improvement in physical, hydro-physical and biological properties of soil was observed, together with the rebuilt of structure and increase of water permeability of soil. The minimum tillage systems ensure an adequate aerial-hydrical regime for the biological activity intensity and for the nutrients solubility equilibrium. The vegetal material remaining at the soil surface or superficially incorporated has its contribution to intensifying the biological activity, being an important resource of organic matter. The minimum tillage systems rebuild the soil structure, improving the global drainage of soil which allows a rapid infiltration of water in soil. The result is a more productive soil, better protected against wind and water erosion and needing less fuel for preparing the germination bed. Presently it is necessary a change concerning the concept of conservation practices and a new approach regarding the control of erosion. The real conservation of soil must be expanded beyond the traditional understanding of soil erosion. The real soil conservation is represented by carbon management. We need to focus to another level concerning conservation by focusing on of soil quality. Carbon management is necessary for a complex of matters including soil, water management, field productivity, biological fuel and climatic change. Profound research is necessary in order to establish the carbon sequestration practices and their implementation impact.

Rusu, Dr.; Gus, Dr.; Bogdan, Dr.; Moraru, Dr.; Pop, Dr.; Clapa, Dr.; Pop, Drd.

2009-04-01

92

Soil tillage conservation and its effect on erosion control, water management and carbon sequestration  

NASA Astrophysics Data System (ADS)

The energetic function of the soil expressed through the potential energy accumulated through humus, the biogeochemical function (the circuit of the nutrient elements) are significantly influenced by its hydrophysical function and especially by the state of the bedding- consolidation, soil capacity of retaining an optimal quantity of water, and then its gradual disponibility for plant consumption. The understanding of soil functions and management including nutrient production, stocking, filtering and transforming minerals, water , organic matter, gas circuit and furnishing breeding material, all make the basis of human activity, Earth's past, present and especially future. The minimum tillage soil systems - paraplow, chisel or rotary grape - are polyvalent alternatives for basic preparation, germination bed preparation and sowing, for fields and crops with moderate loose requirements being optimized technologies for: soil natural fertility activation and rationalization, reduction of erosion, increasing the accumulation capacity for water and realization of sowing in the optimal period. By continuously applying for 10 years the minimum tillage system in a crop rotation: corn - soy-bean - wheat - potato / rape, an improvement in physical, hydro-physical and biological properties of soil was observed, together with the rebuilt of structure and increase of water permeability of soil. The minimum tillage systems ensure an adequate aerial-hydrical regime for the biological activity intensity and for the nutrients solubility equilibrium. The vegetal material remaining at the soil surface or superficially incorporated has its contribution to intensifying the biological activity, being an important resource of organic matter. The minimum tillage systems rebuild the soil structure, improving the global drainage of soil which allows a rapid infiltration of water in soil. The result is a more productive soil, better protected against wind and water erosion and needing less fuel for preparing the germination bed. Presently it is necessary a change concerning the concept of conservation practices and a new approach regarding the control of erosion. The real conservation of soil must be expanded beyond the traditional understanding of soil erosion. The real soil conservation is represented by carbon management. We need to focus to another level concerning conservation by focusing on of soil quality. Carbon management is necessary for a complex of matters including soil, water management, field productivity, biological fuel and climatic change.

Rusu, T.; Gus, P.; Bogdan, I.; Moraru, P.; Pop, A.; Clapa, D.; Pop, L.

2009-04-01

93

Soil erosion and conservation  

SciTech Connect

This is a review of worldwide land degradation problems. Four themes are emphasized: delineating and estimating the magnitude of soil erosion, quantifying erosion and sedimentation impacts on land productivity, establishing quantitative values for erosion-causing parameters, and implementing global and regional soil and water conservation programs. Papers deal with both developing and developed countries and illustrate how erosion control techniques used in developed countries can or cannot be applied in developing countries.

El-Swaify, S.A.; Moldenhauer, W.C.; Lo, A.

1985-01-01

94

Robotic weld overlay coatings for erosion control. Quarterly progress report, October 1993--December 1993  

SciTech Connect

Research is being conducted to develop criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. Twelve weld overlay alloys were deposited on 1018 steel substrates using plasma arc welding. Ten samples from each coating were prepared for erosion testing. All selected coatings were erosion tested at 400C and their erosion resistance and microstructure evaluated. Steady state erosion rates were similar for several weld overlay coatings (Ultimet, Inconel-625, Iron-Aluminide, 316L SS, and High Chromium Cast Iron) and were considerably lower than the remaining coating evaluated. These coatings had different base (Co, Fe, Ni-base). No correlations were found between room temperature microhardness of the weld overlay coatings and their erosion resistance at elevated temperature, although this criteria is often thought to be an indicator of erosion resistance. It was suggested that the coatings that showed similar erosion rates may have similar mechanical properties such as fracture strength, toughness and work hardening rates at this temperature. During the past quarter, Iron-Aluminide, Inconel-625, and 316L SS coatings were selected for more detailed investigations based upon the preliminary erosion test results. Microhardness tests were performed on eroded samples to determine the size of the work hardened zone and change in coatings hardness due to erosion. The work hardened zone was to correlated with erosion resistance of the coatings. Additional Iron-Aluminide, Inconel-625, and 316L SS coatings were deposited on 1018 steel substrates.

Levin, B.F.; DuPont, J.N.; Marder, A.R.

1994-01-20

95

Robotic weld overlay coatings for erosion control. Quarterly technical progress report, July--September, 1994  

SciTech Connect

Research is presently being conducted to develop a criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. Initially, eleven weld overlay alloys were selected for erosion testing based upon a literature review. All eleven coatings were deposited on 1018 steel substrates using the plasma arc welding process. Ten samples from each coating were prepared for erosion testing. All selected coatings were erosion tested at 400 C and their erosion resistance was evaluated by determining the steady state erosion rate. In addition, the microstructure of each coating was characterized before and after the erosion tests. No correlations were found between room temperature hardness of the weld overlay coatings and their erosion resistance at elevated temperature. It was suggested that weld overlays mechanical properties such as fracture strength, toughness and work hardening rates may contributed to their erosion resistance. During the previous two quarters the microhardness tests were performed on the eroded samples in order to determine the size of the work hardened zone and the change in the coatings hardness due to erosion. As a result of these measurements it was established that one group of coatings deformed plastically, while another did not. In addition, the measurements of the weld overlays microhardness at 400 C were made. The coatings microhardness at 400 C was plotted versus their volume erosion rates. During the last quarter, erosion tests were performed for Inconel-625, 316L SS, and Iron-Aluminide wrought alloys in order to compare their erosion behavior with similar weld overlays. The results of microhardness profile measurements for all weld overlay coatings were analyzed. The factors that contribute to the erosion resistance of the coatings that deformed plastically are discussed in this progress report.

Levin, B.F.; Dupont, J.N.; Marder, A.R.

1994-10-26

96

Validation of Erosion 3D in Lower Saxony - Comparison between modelled soil erosion events and results of a long term monitoring project  

NASA Astrophysics Data System (ADS)

Since 2000 water erosion has been surveyed on 400 ha arable land in three different regions of Lower Saxony (Mosimann et al. 2009). The results of this long-term survey are used for the validation of the soil erosion models such as USLE and Erosion 3D. The validation of the physically-based model Erosion 3D (Schmidt & Werner 2000) is possible because the survey analyses the effects (soil loss, sediment yield, deposition on site) of single thunder storm events and also maps major factors of soil erosion (soil, crop, tillage). A 12.5 m Raster DEM was used to model the soil erosion events.Rainfalldata was acquired from climate stations. Soil and landuse parameters were derived from the "Parameterkatalog Sachsen"(Michael et al. 1996). During thirteen years of monitoring, high intensity storms fell less frequently than expected. High intensity rainfalls with a return period of five or ten years usually occurred during periods of maximum plant cover.Winter events were ruled out because dataon snow melt and rainfallwere not measured. The validation is therefore restricted to 80 events. The validation consists of three parts. The first part compares the spatial distribution of the mapped soil erosion with the model results. The second part calculates the difference in the amount of redistributed soil. The third part analyses off-site effects such as sediment yield and pollution of water bodies. The validation shows that the overall result of erosion 3D is quite good. Spatial hotspots of soil erosion and of off-site effects are predicted correctly in most cases. However, quantitative comparison is more problematic, because the mapping allows only the quantification of rillerosion and not of sheet erosion. So as a rule,the predicted soil loss is higher than the mapped. The prediction of rill development is also problematic. While the model is capable of predicting rills in thalwegs, the modelling of erosion in tractor tracks and headlands is more complicated. In order to obtain better results, the DEM needs a higher resolution, and soil and landuse parameters have to been optimized in tractor tracks and headlands (higher bulk density, less coverage). Other models like LINERO (Bug &Mosimann 2012) can help to get an overview over the location of erosion forms and the soil loss due to rill erosion. References: Bug J., & T. Mosimann (2012): Modellierung der linearen Bodenerosion. Entwicklung eines entscheidungsbasierten Modells zur flächenhaften Prognose der linearen Erosionsaktivität, Geosynthesis 15, Hannover, 105 S. Michael, A., Schmidt, J. & W. A. Schmidt (1996): EROSION 2D/3D - Ein Computermodell zur Simulation der Bodenerosion durch Wasser. Parameterkatalog Sachsen, Freiberg. Mosimann, T., Bug, J. Sanders, S. & F. Beisiegel (2009): Bodenerosionsdauerbeobachtung in Niedersachsen 2000-2008. Methodik, Erosionsgeschehen, Bodenabträge und Anwendung der Ergebnisse, Geosynthesis 14, Hannover, 101 S. Schmidt, J., & M. v. Werner (2000): Modeling sediment and heavy metal yields of drinking water reservoirs in the Osterzgebirge region of Saxony (Germany). In: Schmidt, J. (Ed.), Soil Erosion—Application of Physically Based Models. Springer, Berlin, Heidelberg, New York, pp. 93- 108.

Bug, Jan; Mosimann, Thomas

2013-04-01

97

UMTRA Project document control system manual  

SciTech Connect

This manual defines the Project Document Control System (PDCS) operated by the US DOE Uranium Mill tailings Remedial Action (UMTRA) project Office. The purpose of the PDCS is to provide an active and continuing program for acquiring, controlling, retaining, retrieving, retiring and disposing of all UMTRA Project documents. The PDCS also provides guidance and coordination in transferring documents by various UMTRA Projection document control centers to a central location.

Not Available

1994-09-01

98

Soil erosion analysis of human influence on the controlled basin system of check dams in small watersheds of the Loess Plateau, China  

Microsoft Academic Search

An observability–controllability model of periphery (COMP) is presented based on the system theory. A soil erosion analysis approach is deduced based on the COMP and applied to the quantitative analysis of human influence on soil erosion from the controlled area of Check Dam Shipanmao in the hilly and gully region of the Loess Plateau in China. The controlled area of

Xun-Gui Li; Xia Wei

2011-01-01

99

PLATELET ACTIVATING FACTOR AND DISTINCT CHEMOKINES ARE ELEVATED IN MUCOSAL BIOPSIES OF EROSIVE COMPARED TO NON-EROSIVE REFLUX DISEASE PATIENTS AND CONTROLS  

PubMed Central

Background A distinction between symptomatic non-erosive reflux disease (NERD) and erosive esophagitis (EE) patientsis supported by the presence of inflammatory response in the mucosa of EE patients, leading to a damage of mucosal integrity. To explore the underlying mechanism of this difference we assessed inflammatory mediators in mucosal biopsies from EE and NERD patients and compared them to controls. Methods Nineteen NERD patients, fifteen EE patients and sixteen healthy subjects underwent endoscopy after a 3-week washout from PPI or H2 antagonists. Biopsies obtained from the distal esophagus, were examined by quantitative real-time polymerase chain reaction (qPCR) and multiplex ELISA for selected chemokines and lyso-PAF acetyltransferase (LysoPAF-AT), the enzyme responsible for production of platelet activating factor (PAF). Results Expression of LysoPAF-AT and multiple chemokines was significantly increased in mucosal biopsies derived from EE patients, when compared to NERD patients and healthy controls. Upregulated chemokines included interleukin 8, eotaxin-1, -2 and -3, macrophage inflammatory protein-1? (MIP-1?) and monocyte chemoattractant protein-1 (MCP-1). LysoPAF-AT and the chemokine profile in NERD patients were comparable to healthy controls. Conclusions Levels of selected cytokines and Lyso-PAF AT were significantly higher in the esophageal mucosa of EE patients compared to NERD and control patients. This difference may explain the distinct inflammatory response occurring in EE patients’ mucosa. In contrast, since no significant differences existed between the levels of all mediators in NERD and control subjects, an inflammatory response does not appear to play a major role in the pathogenesis of the abnormalities found in NERD patients. PMID:22734465

Altomare, A.; Ma, J.; Guarino, M.P.L.; Cheng, L.; Rieder, F.; Ribolsi, M.; Fiocchi, C.; Biancani, P.; Harnett, K.; Cicala, M.

2012-01-01

100

Robotic weld overlay coatings for erosion control. Quarterly technical progress report, October 1994--December 1994  

SciTech Connect

Research is presently being conducted to develop a criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. Initially, eleven weld overlay alloys were selected for erosion testing based upon a literature review. All eleven coatings were deposited on 1018 steel substrates using the plasma arc welding process. Ten samples from each coating were prepared for erosion testing. The coating deposition and sample preparation procedures were described in the second quarterly report. All selected coatings were erosion tested at 400{degree}C and their erosion resistance was evaluated by determining the steady state erosion rate. In addition, the microstructure of each coating was characterized before and after the erosion tests. The results of the tests are discussed in the third quarterly report. No correlations were found between room temperature hardness of the weld overlay coatings and their erosion resistance at elevated temperature. During the last quarter tensile tests were performed at 400{degree}C for the Ultimet, Inconel-625, 316L SS, C-22, and Stellite-6 wrought alloys. The erosion tests for these materials at 400{degree}C are in progress. The results of mechanical and erosion tests will be used to correlate mechanical properties of selected wrought alloys such as tensile toughness, ductility, strain hardening coefficient and yield strength to their erosion resistance at 400{degree}C. Also, the erosion behavior of the wrought alloys compared with similar weld alloys will be analyzed. The experimental procedure and results of the tensile tests are presented in this progress report.

Levin, B.F.; Dupont, J.N.; Marder, A.R.

1995-01-25

101

NASA's Evolutionary Xenon Thruster (NEXT) Project Qualification Propellant Throughput Milestone: Performance, Erosion, and Thruster Service Life Prediction After 450 kg  

NASA Technical Reports Server (NTRS)

The NASA s Evolutionary Xenon Thruster (NEXT) program is tasked with significantly improving and extending the capabilities of current state-of-the-art NSTAR thruster. The service life capability of the NEXT ion thruster is being assessed by thruster wear test and life-modeling of critical thruster components, such as the ion optics and cathodes. The NEXT Long-Duration Test (LDT) was initiated to validate and qualify the NEXT thruster propellant throughput capability. The NEXT thruster completed the primary goal of the LDT; namely to demonstrate the project qualification throughput of 450 kg by the end of calendar year 2009. The NEXT LDT has demonstrated 28,500 hr of operation and processed 466 kg of xenon throughput--more than double the throughput demonstrated by the NSTAR flight-spare. Thruster performance changes have been consistent with a priori predictions. Thruster erosion has been minimal and consistent with the thruster service life assessment, which predicts the first failure mode at greater than 750 kg throughput. The life-limiting failure mode for NEXT is predicted to be loss of structural integrity of the accelerator grid due to erosion by charge-exchange ions.

Herman, Daniel A.

2010-01-01

102

Use of hold-gro erosion control fabric in the establishment of plant species on coal mine soil.  

PubMed

Experiments were conducted on the Black Mesa Coal Mine, Kayenta, Arizona in 1977 and 1978 to study the effectiveness of Hold-Gro Erosion Control Fabric (a product from the Gulf States Paper Corporation, Tuscaloosa, Alabama) in the establishment of plants on coal mine soil following the surface mining of coal. Four plant species were planted: (1) spring barley (Horduem vulgare L.), an annual grass (2) crested wheatgrass (Agropyron cristatum L.), a perennial grass (3) alfalfa (lucerne) (Medicago sativa L.), a perennial legume and (4) fourwing saltbush (Atriplex canescens Pursh.), a perennial shrub. Seeds of each plant species were planted in reclaimed coal mine soil in the spring of the year by both broadcast seeding (conventional culture) and the incorporation of seeds in Hold-Gro Erosion Control Fabric. Average numbers of seedlings established and percent ground cover for all species studied were higher in areas where conventional culture was used than they were in areas where seeds were incorporated in Hold-Gro Erosion Control Fabric. The incorporation of seeds in Hold-Gro Erosion Control Fabric in the establishment of plant species on coal mine soil was not an effective cultural practice in the southwestern United States. PMID:24214010

Day, A D; Ludeke, K L

1986-09-01

103

Biodiversity in riverbank techniques for erosion control: assessment of animal and plant species diversity along a natural gradient.  

E-print Network

and ecological succession processes. We compared plant species diversity and animal taxonomic diversity aboveBiodiversity in riverbank techniques for erosion control: assessment of animal and plant species * Corresponding author: paul.cavaille@cemagref.fr Keywords: beetles, biodiversity, ecological restoration, plant

Paris-Sud XI, Université de

104

Erosion control technology: a user's guide to the use of the Universal Soil Loss Equation at waste burial facilities  

SciTech Connect

The Universal Soil Loss Equation (USLE) enables the operators of shallow land burial sites to predict the average rate of soil erosion for each feasible alternative combination of plant cover and land management practices in association with a specified soil type, rainfall pattern, and topography. The equation groups the numerous parameters that influence erosion rate under six major factors, whose site-specific values can be expressed numerically. Over a half century of erosion research in the agricultural community has supplied information from which approximate USLE factor values can be obtained for shallow land burial sites throughout the United States. Tables and charts presented in this report make this information readily available for field use. Extensions and limitations of the USLE to shallow land burial systems in the West are discussed, followed by a detailed description of the erosion plot research performed by the nuclear waste management community at Los Alamos, New Mexico. Example applications of the USLE at shallow land burial sites are described, and recommendations for applications of these erosion control technologies are discussed.

Nyhan, J.W.; Lane, L.J.

1986-05-01

105

Robotic weld overlay coatings for erosion control. Quarterly technical progress report, January 1995--March 1995  

SciTech Connect

Research is presently being conducted to develop a criteria for selecting weld overlay coatings for erosion mitigation in Circulated Fluidized Beds. During the last two quarters tensile tests were performed at 400{degrees}C for the Ultimet, Inconel-625, 316L SS, C-22, and Stellite-6 wrought alloys. Also, the erosion tests for these materials at 400{degrees}C were completed. The results of mechanical and erosion tests are used to correlate mechanical properties of selected wrought alloys such as tensile toughness, ductility, strain hardening coefficient and yield strength to their erosion resistance at 400{degrees}C. Preliminary results of correlations between erosion resistance of wrought alloys at 400{degrees}C and their mechanical properties are presented in this progress report.

Levin, B.F.; Dupont, J.N.; Marder, A.R.

1995-04-25

106

Weld overlay coatings for erosion control. Task A: Literature review, progress report  

SciTech Connect

A literature review was made. In spite of similarities between abrasive wear and solid particle erosion, weld overlay hardfacing alloys that exhibit high abrasion resistance may not necessarily have good erosion resistance. The performance of weld overlay hardfacing alloys in erosive environments has not been studied in detail. It is believed that primary-solidified hard phases such as carbides and intermetallic compounds have a strong influence on erosion resistance of weld overlay hardfacing alloys. However, relationships between size, shape, and volume fraction of hard phases in a hardfacing alloys and erosion resistance were not established. Almost all hardfacing alloys can be separated into two major groups based upon chemical compositions of the primary solidified hard phases: (a) carbide hardening alloys (Co-base/carbide, WC-Co and some Fe base superalloys); and (b) intermetallic hardening alloys (Ni-base alloys, austenitic steels, iron-aluminides).

Levin, B.; DuPont, J.N.; Marder, A.R.

1993-03-03

107

Oral pantoprazole for erosive esophagitis: a placebo-controlled, randomized clinical trial  

Microsoft Academic Search

OBJECTIVES:The aim of this dose-response study was to compare the effectiveness of 10 mg, 20 mg, and 40 mg of pantoprazole with that of placebo tablets in the healing and symptom relief of gastroesophageal reflux disease associated with erosive esophagitis, and to determine the optimal dose.METHODS:A total of 603 patients with endoscopically confirmed (Hetzel-Dent scale) erosive esophagitis of grade 2

Joel E. Richter; Wieslaw Bochenek

2000-01-01

108

Laboratory Projects in Intelligent Control  

E-print Network

. Explain, using the physics of the plant, why the rules you choose make sense. Implement the fuzzy for the plant based on the use of a mathematical model of the plant (e.g., one based on feedback linearization Control: Design a fuzzy controller for a plant in the laboratory that exhibits strong nonlinear behavior

109

[Anti-erosion effect of hedgerows in hillside croplands of Danjiangkou based on the evaluation with water erosion prediction project (WEPP) model].  

PubMed

Based on the data of field experiments on the hillside croplands of Danjiangkou, Hubei Province of China, the input files of crop characters, management measures, slope gradient and length, and soil properties for running WEPP model (Hillslope version) were established. Combining with the local weather data, a simulation study with the model was made on the runoff and soil loss of the croplands protected by four kinds of hedgerows (Amorpha fruticosa, Lonicera japonica, Hemerocallis fulva, and Poa sphondylodes) in Danjiangkou area. The resulted showed that WEPP model could accurately simulate the anti-erosion effect of hedgerows in hillside farmlands in the study area. Using this model not only reduced test number, but also saved time and effort, being able to provide scientific basis for the popularization and application of hedgerows. Among the four hedgerows, Amorpha fruticosa had the best anti-erosion effect. According to the simulation, the optimal planting density of A. fruticosa hedgerows in the farmlands was 1 m x 15 m at slope gradient 5 degrees, 1 m x 10 m at slope gradient 15 degrees, and 1 m x 3 m at slope gradient 25 degrees. PMID:21265164

Xiong, Qin-xue; Liu, Zhang-yong; Yao, Gui-zhi; Li, Ben-zhou

2010-09-01

110

Version control in project-based learning  

Microsoft Academic Search

This paper deals with the development of a generalized model for version control systems application as a support in a range of project-based learning methods. The model is given as UML sequence diagram and described in detail. The proposed model encompasses a wide range of different project-based learning approaches by assigning a supervisory role either to instructor or students in

Ivan Milentijevic; Vladimir Ciric; Oliver Vojinovic

2008-01-01

111

Reducing Erosion and Runoff  

NSDL National Science Digital Library

Reducing Erosion and Runoff, from the Virginia Cooperative Extension, describes what erosion and runoff are, methods of control, including the use of plants and groundcover selection. The site also describes how to handle steep slopes and some steps for building and protecting soil. This information can also be downloaded as a pdf.

2008-07-24

112

Robotic weld overlay coatings for erosion control. Quarterly technical progress report, April 1993--June 1993  

SciTech Connect

Twelve weld overlay hardfacing alloys have been selected for preliminary erosion testing based upon a literature review. Four of the selected coatings were deposited on a 1018 steel substrate using plasma arc welding process. During the past quarter, the remaining eight coatings were deposited in the same manner. Ten samples from each coatings were prepared for erosion testing. Microstructural characterization of each coating is in progress. This progress report describes coating deposition and sample preparation procedures. Relation between coatings hardness and formation of cracks in coatings is discussed.

Levin, B.F.; Dupont, J.N.; Marder, A.R.

1993-07-20

113

Tectonic uplift and climate controlling erosion along the Southern Himalayan Front  

NASA Astrophysics Data System (ADS)

The spatial and temporal evolution of rock uplift in active orogens provide valuable insights into the relations between surface and tectonic processes, and topography. A prime example is the humid western and central part of the southern Himalayan mountain front, where rainfall is high and evenly distributed. In the orographic rain shadow north of the Shillong Plateau (25N, 91E) located 250 km south of the eastern mountain front, annual rainfall decreases to 70% from west to east (i.e. 6m/a vs. < 1.7m/a). Other areas with low precipitation occur along the entire southern Himalayan front at elevations over 3000m, where moisture has fallen as rain at lower elevations. Along the entire southern Himalayan front, lithology, tectonic style and neotectonic activity do not vary strongly along strike. Therefore, substantial along-strike variations of topography possibly reflect local differences in uplift and climate-controlled erosion. Digital elevation models were used in an analysis of topography and channel gradients. Precipitation data are based on calibrated passive microwave data (SSMI) with a spatial resolution of 12.5 km2; DEMs along the Southern Himalayan Front were generated using the GTOPO30 data set. High-resolution topographic data (1:25,000, 1:50,000 and 1:100,000 maps) were used to characterize geomorphology in several areas. The N-S trending Sutlej Valley (32N, 78E) is drained by the antecedent Sutlej River which cuts through the Tethyan Himalaya, High and Lower Himalayan Crystalline, and the Lesser Himalaya. The Arun (27N, 87E) and Manas valleys (27.5N, 91.5E) have a similar lithology and geologic structures, but the latter lies within the orographic rain shadow of the Shillong Plateau. Significantly diverse topographic swath profiles that show steep slopes in high precipitation areas while gentler slopes dominate in dry areas. All sectors with evenly distributed high orographic precipitation and runoff to elevations of approximately 3000m have smooth channel gradients. Above this elevation, rainfall decreases dramatically and knickpoints exist. River profiles of bedrock channels draining these high areas have high steepness indices (a measure of profile gradient normalized to drainage area). This observation shows that despite active tectonism knickpoint formation in the topographically lower and more humid segments of the profiles is counteracted by high erosional capacity and incision. In contrast to the humid Himalayan front, river profiles in the rain shadow north of the Shillong Plateau occur in a comparable setting regarding lithology, tectonism, and elevation to rivers in the higher, more arid parts of the Himalayan front. The regions north of the Shillong Plateau receive between 15 and 40% of the amount of precipitation in the lower elevated western sectors. Behind the Shillong Plateau river profiles within the lower elevation regions (up to 3000 m) are steeper and characterized by pronounced knickpoints. This is thus similar to knickpoint formation in the more arid, higher elevation regions along the rest of the southern Himalayan front. The evolution of longitudinal river profiles in this region is therefore clearly influenced by an effective erosive climate in those sectors of the orogen, where precipitation is high. This is in line with preliminary results from fission-track thermochronology that indicate high denudation/uplift rates in sectors with high precipitation, moderate rates at elevations of about 3000m, and lower rates that characterize drier regions in excess of 3000m, as well as leeward sectors behind the Shillong Plateau.

Bookhagen, B.; Thiede, R.

2001-12-01

114

Natural and anthropogenic controls on soil erosion in the Internal Betic Cordillera (southeast Spain)  

Microsoft Academic Search

Soil erosion in southeast Spain is a complex process due to strong interactions between biophysical and human components. Significant progress has been achieved in the understanding of soil hydrological behavior, despite the fact that most investigations were focused on the experimental plot scale. Although experimental plots allow exploring the effect of multiple biophysical and anthropogenic factors, they provide limited insights

N. Bellin; V. Vanacker; B. van Wesemael; A. Solé-Benet; M. M. Bakker

2011-01-01

115

Vetiver Grass System for Erosion Control on Severe Acid Sulfate Soil in Southern Vietnam  

Microsoft Academic Search

The banks of drainage and irrigation channels in the acid sulfate soil (ASS) region of southern Vietnam are highly erodible due to weak or no physical structure and the extremely acidic chemical conditions. With these soil properties, most plants cannot survive; especially during dry season hence erosion is severe and results in costly repairs. Vetiver grass has been used successfully

Le van Du; Paul Truong

116

THE ROLE OF VETIVER GRASS IN EROSION CONTROL AND SLOPE STABILIZATION ALONG THE HIGHWAYS OF THAILAND  

Microsoft Academic Search

At His Majesty the King of Thailand's initiative, in 1993 the Department of Highways instructed its highway construction and maintenance units to plant vetiver grass on the slope areas of 113 highways for soil erosion prevention. Over 6.5 million tillers have been planted, either in rows or in clump patterns in slopy areas, depending on the seriousness and the tendency

Surapol Sanguankaeo; Chawalit Sukhawan; Ekawit Veerapunth

117

Erosion Effects  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

The impact crater in this THEMIS image is a model illustration to the effects of erosion on Mars. The degraded crater rim and several landslides observed in crater walls is evidence to the mass wasting of materials. Layering in crater walls also suggests the presence of materials that erode at varying rates.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude 31.6, Longitude 44.3 East (315.7 West). 19 meter/pixel resolution.

2003-01-01

118

This project studied the effects of urbanization on flooding and erosion of small streams in the District of Columbia. The Hickey Run, which covers 1075 acres (435 ha)  

E-print Network

#12;ABSTRACT This project studied the effects of urbanization on flooding and erosion of small selected for the study. The 100-year floods were estimated at 2,230 ft3/s (62m3/s) in the Hickey Run, and 3 floods in the Hickey Run was estimated at 2,230 ft 3/s (62 m3/s) and 3,292 ft3/s (92m3/s) in the Watts

District of Columbia, University of the

119

[Influence of three types of riparian vegetation on fluvial erosion control in Pantanos de Centla, Mexico].  

PubMed

Wetlands constitute very important ecological areas. The aim of this study was to quantify the soil losses due to fluvial erosion from 2006 to 2008 in two riverbanks under three types of vegetal coverage dominated by Haematoxylum campechianum, Dalbergia brownei and Brachiaria mutica, in the Pantanos de Centla Biosphere Reserve, SE Mexico. The relationship between the texture, organic matter and pH of soils and soil losses was evaluated. We used erosion sticks to estimate soil losses in 18 plots (three plots per type, three vegetation types, two riverbanks). Soil loss decreased in this order: H. campechianum>B. mutica>D. brownei indicating that D. brownei scrubland has the most potential to retain soil. The higher erosive impact within H. campechianum sites can be related with the low density of these trees in the study areas, as well as the lack of association with other types of vegetation that could reinforce the rooting of the soil profile. Furthermore, soil losses in H. campechianum sites were dependent on soil texture. The soils under this type of vegetal coverage were mainly sandy, which are more vulnerable to the erosive action in comparison with fine textured soils or soils with higher clay content, like the ones found in D. brownei and B. mutica sites. Soil losses of 100 % in the second year (B. mutica plots) can be attributed to the distribution of roots in the upper soil layer and also to livestock management along riverbanks. This study recognizes the importance of D. brownei scrublands in riverbank soil retention. Nevertheless it is necessary to consider the role of an entire vegetal community in future research. PMID:20073341

Sepúlveda-Lozada, Alejandra; Geissen, Violette; Ochoa-Gaona, Susana; Jarquín-Sánchez, Aarón; de la Cruz, Simón Hernández; Capetillo, Edward; Zamora-Cornelio, Luis Felipe

2009-12-01

120

An investigation of bergmounds as analogs to erosion control factors on protective barriers  

SciTech Connect

Included in several of the final disposal strategies proposed in the Interim Hanford Waste Management Plan (DOE-RL 1986a) is design of a protective barrier to isolate the underlying waste sites from the environment. The conceptual protective barrier design requires a fine-grained sediment to retain precipitation near the top of the barrier where evapotranspiration can recycle the moisture back into the atmosphere. The design incorporates gravel into the topsoil as one way to reduce its erosion. Information is needed to determine the optimal ratio of gravel to topsoil needed to reduce erosion without significantly reducing evapotranspiration, and its effect on erosion. Bergmounds are mounds with a gravelly surface that were formed about 13,000 years ago and represent natural analogs to the topsoil portion of the protective barrier. The primary goal of this study was to identify characteristics of bergmounds and the effects of these characteristics, especially the gravelly surface, on the amount and rate of erosion. A secondary goal was to apply a technique normally used to estimate vegetation cover to measure percent gravel cover, and to compare this technique with particle size distribution based on weight percent. Four bergmounds were investigated for this study, two in a windy site and two in a more sheltered site. Each bergmound was sampled in eight locations. Two methods were used to estimate the amount of surface gravel: the ocular point-intercept method which estimates the percent gravel cover, and sieved samples of the surface sediments which measure the percent gravel by weight. Holes were dug at each bergmound`s eight sampling sites to examine and sample the subsurface sediments.

Chamness, M.A.

1993-09-01

121

Radial Erosion  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

The ejecta surrounding the crater (off image to the left) in this image has undergone significant erosion by the wind. The wind has stripped the surface features from the ejecta and has started to winnow away the ejecta blanket. Near the margin of the ejecta the wind is eroding along a radial pattern -- taking advantage of radial emplacement. Note the steep margin of the ejecta blanket. Most, if not all, of the fine ejecta material has been removed and the wind in now working on the more massive continuous ejecta blanket.

Image information: VIS instrument. Latitude 12.5, Longitude 197.4 East (162.6 West). 37 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2005-01-01

122

Ecosystem-controlled Erosion in a Loess-mantled Landscape in Eastern Washington  

NASA Astrophysics Data System (ADS)

Vegetation varies with climate so it is important to constrain how different vegetation types affect sediment transport. In forested landscapes, tree throw plays a large role in increased sediment transport relative to shrub and grassland. In this study, we quantify soil transport rates in a coniferous forest using hillslope profiles and tephra abundance. The loess-mantled hillslopes of Robinette Mountain in the Blue Mountains, confining the southeastern edge of the Columbia Plateau in southeast Washington State, USA, have been forested since the Holocene transition. Approximately 6800 years ago, the eruption of Mt. Mazama blanketed the region with tephra. Near the crest of hillslopes of different degrees of convexity, we identified and sampled soils for cryptotephra analysis. The depth of the tephra abundance spike is used as a proxy for erosion/exhumation rate since deposition. The slope dependent sediment transport model suggests that the change in elevation with time (or landscape lowering rate) is proportional to the hillslope curvature, with the constant of proportionality referred to as K (m2 yr-1). Therefore, we surveyed slope morphology for comparison with erosion rate at each site. K generally depends on processes such as soil creep, rain splash, variations in soil moisture (wet/dry) and temperature (freeze/thaw), tree throw, and faunal burrowing/biogenic activity. By estimating the value of K we can relate sediment transport to dominant processes in our forested landscape, such as frequency of tree turnover or faunal burrowing, and determine the spatial variability of erosion rates and sediment delivery using topographic hillslope surveys.

Walther, S. C.; Roering, J. J.; Almond, P. C.; Hughes, M.

2005-12-01

123

Analysis/control of in-bed tube erosion phenomena in the fluidized bed combustion system. Final technical report  

SciTech Connect

Research is presented on erosion and corrosion of fluidized bed combustor component materials. The characteristics of erosion of in-bed tubes was investigated. Anti-corrosion measures were also evaluated.

Lee, Seong W.

1996-11-01

124

Effects of erosion control structures along a portion of the northern Chesapeake Bay shoreline  

USGS Publications Warehouse

A 6.500-meter reach of western Chesapeake Bay shoreline (lower Mayo Peninsula) lost about 1.1??106 cubic meters of sediment (equivalent to 170 cubic meters lost per meter of shoreline) between 1846 and 1932, when the first aerial photographs show the shoreline already substantially protected by a system of groins and intermittent bulkheading. These structures have eliminated the fastland as a source of erodable material, and have starved the supply of sand for littoral drift, thus limiting the extent of the beaches to the remaining groin fields. Volumes of sediment involved in these impacts are small in the overall sediment budget. Bulkheads produce no deficit in the budget since scouring of the beaches on their seaward sides makes up for the decreased erosion of protected fastland. Groins trap little of the potential littoral drift (computed to be about 104 cubic meters per meter of shoreline per year). The sand supply in the remaining beaches is nearly equivalent to the annual loss of sediment from the entire shoreline system due to the long-term rate of erosion of the shoreline and nearshore between 1846 and 1932. ?? 1981 Springer-Verlag New York Inc.

Zabawa, C.F.; Kerhin, R.T.; Bayley, S.

1981-01-01

125

Assessment of Soil Moisture and Fixatives Performance in Controlling Wind Erosion of Contaminated Soil at the Hanford Site  

SciTech Connect

During the remediation of burial grounds at the US Department of Energy's (DOE's) Hanford Site in Washington State, the dispersion of contaminated soil particles and dust is an issue that is faced by site workers on a daily basis. This contamination issue is even more of a concern when one takes into account the semi-arid characteristics of the region where the site is located. To mitigate this problem, workers at the site use a variety of engineered methods to minimize the dispersion of contaminated soil and dust particles. Once such methods is the use of water and/or suppression agents (fixatives) that stabilizes the soil prior to soil excavation, segregation, and removal activities. A primary contributor to the dispersion of contaminated soil and dust is wind soil erosion. The erosion process occurs when the wind speed exceeds a certain threshold value (threshold shear velocity), which depends on a number of factors including wind force loading, particle size, surface soil moisture, and the geometry of the soil. Thus under these circumstances the mobility of contaminated soil and generation and dispersion of particulate matter are significantly influenced by these parameters. Wind tunnel experiments were conducted at the Florida International University's Applied Research Center (FIU-ARC) to evaluate the effectiveness of three commercially available fixatives in controlling the mobility of soil particles on soil mounds when exposed to varying wind forces. The fixatives tested included: (1) a calcium chloride solution; (2) a petroleum hydrocarbon emulsion; and 3) a synthetic organic. As an initial step, approximately 500 lbs of uncontaminated soil was obtained from the Hanford Reservation in Washington State. Soil samples were placed in an open-loop, low speed wind tunnel and exposed to wind forces ranging from 10 to 30 miles per hour (mph). Wind erosion controlling capabilities of commercially available fixatives and soil moisture were tested at a laboratory scale. Soil samples with varying moisture (W/W %) content and soil samples treated with fixatives, selected from a wide range of commercially available products, were exposed to a wind speeds ranging from 10 - 30 miles per hour (MPH). During these experiments, amount of soil displaced due to the wind forces, the amount of airborne particulates generated, and the moisture loss were measured to better understand the performance of selected fixatives and soil moisture. Results obtained during the study showed that there is a significant reduction in wind erosion and airborne particles generation by increasing the soil moisture for the velocities tested. Similar trend was observed when the soil samples treated with fixatives were exposed to the same range of velocities (10 - 30 MPH). (authors)

Lagos, L.E.; Gudavalli, R.K. [Applied Research Center, Florida International Univ., Miami, FL (United States)

2008-07-01

126

The AFIT gross motion control project  

NASA Technical Reports Server (NTRS)

The objective of the Gross Motion Control project is to study alternative control approaches that will provide payload invariant high speed trajectory tracking for nonrepetitive motions in free space. The research has concentrated on modifications to the model-based control structure. Development and evaluation is being actively pursued of both adaptive primary (inner loop) and robust secondary (output loop) controllers. In-house developments are compared and contrasted to the techniques proposed by other researchers. The case study for the evaluation is the first three links of a PUMA-560. Incorporating the principals of multiple model adaptive estimation, artificial neural networks, and Lyapunov theory into the model based paradigm has shown the potential for enhanced tracking. Secondary controllers based on Quantitative Feedback Theory, or augmented with auxiliary inputs, significantly improve the robustness to payload variations and unmodeled drive system dynamics. An overview is presented of the different concepts under investigation and a sample is provided of the latest experimental results.

Leahy, M. B., Jr.

1991-01-01

127

Dental Erosion in Industry  

PubMed Central

Five hundred and fifty-five acid workers were examined between March 1962 and October 1964. One hundred and seventy-six (31·7%) were affected by industrial dental erosion at the first examinations. In 33 cases (6·0%) the dentine was affected. During the period of the survey, 66 (20·4%) of 324 workers examined more than once showed evidence that erosion was progressing. The prevalence and incidence of erosion were highest among battery formation workers, lower among picklers, and least among other processes covered by the survey. The age of workers did not appear to influence their susceptibility to erosion. The habit of working with the lips slightly parted had little effect. Erosion superimposed upon attrition predisposed to more severe loss of tooth structure than either operating alone. Little inconvenience or functional disability was suffered by acid workers due to erosion. Twenty-seven (23·7%) of 114 erosions were considered to be disfiguring. Regular dental treatment was sought less by acid workers than by controls, and the oral hygiene of the latter was superior. There was no evidence to show any difference between caries experience among acid workers and controls. Calculus and periodontal disease were more prevalent among acid workers than among controls, but it was not possible to attribute this to the working environment. Black staining in iron picklers was considered to be due to the working environment. The use of closed acid containers or lip extraction on open acid vats prevented significant atmospheric contamination and diminished the prevalence of erosion. The use of wall fans and detergent foaming agents was helpful. Images PMID:5723349

Cate, H. J. Ten Bruggen

1968-01-01

128

Couplages Tectonique -Erosion Berger, 2008  

E-print Network

Couplages Tectonique -Erosion Berger, 2008 #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages Tectonique -Erosion #12;Couplages

Demouchy, Sylvie

129

The spatiotemporal control of erosion and molecular release from micropatterned poly(ethylene glycol)-based hydrogel.  

PubMed

Hydrogels have been extensively studied as a carrier of various hydrophilic molecular compounds and cells for local delivery and subsequent controlled release. One of key design parameters in the hydrogel assembly is an ability to control spatiotemporal gel degradation, in order to tailor release rates of multiple drugs and also regulate phenotypic activities of co-cultured cells. To achieve this goal, this study presents a simple but innovative implantable, microfabricated hydrogel patch that undergoes micropatterned surface erosion at controlled rates and subsequently discharges two molecular compounds of interests at desired rates. This device was prepared by first fabricating a non-degradable poly(ethylene glycol) dimethacrylate (PEGDMA) hydrogel patch containing micro-pockets of controlled spacing and subsequently filling micro-pockets with a hydrogel of poly(ethylene imine) (PEI) and PEG diacrylate (PEGDA) that was tailored to degrade at controlled rates. Separate incorporation of vascular endothelial growth factor (VEGF)121 and VEGF165, known to orchestrate vascular development, into the PEI-PEGDA gel and PEGDMA hydrogel resulted in enhanced neovascularization at the implantation sites due to bimodal, sequential release of two VEGF isoforms. We believe that the hydrogel patch fabricated in this study will be highly useful to better understand a broad array of complex biological processes and also improve the efficacy of molecular cargos in varied applications. PMID:23886733

Yonet-Tanyeri, Nihan; Rich, Max H; Lee, Minkyung; Lai, Mei-Hsiu; Jeong, Jae Hyun; DeVolder, Ross J; Kong, Hyunjoon

2013-11-01

130

Controls on coastal dune morphology, shoreline erosion and barrier island response to extreme storms  

USGS Publications Warehouse

The response of a barrier island to an extreme storm depends in part on the surge elevation relative to the height and extent of the foredunes which can exhibit considerable variability alongshore. While it is recognized that alongshore variations in dune height and width direct barrier island response to storm surge, the underlying causes of the alongshore variation remain poorly understood. This study examines the alongshore variation in dune morphology along a 11??km stretch of Santa Rosa Island in northwest Florida and relates the variation in morphology to the response of the island during Hurricane Ivan and historic and storm-related rates of shoreline erosion. The morphology of the foredune and backbarrier dunes was characterized before and after Hurricane Ivan using Empirical Orthogonal Function (EOF) analysis and related through Canonical Correlation Analysis (CCA). The height and extent of the foredune, and the presence and relative location of the backbarrier dunes, varied alongshore at discrete length scales (of ~ 750, 1450 and 4550??m) that are statistically significant at the 95% confidence level. Cospectral analysis suggests that the variation in dune morphology is correlated with transverse ridges on the inner-shelf, the backbarrier cuspate headlands, and the historical and storm-related trends in shoreline change. Sections of the coast with little to no dune development before Hurricane Ivan were observed in the narrowest portions of the island (between headlands), west of the transverse ridges. Overwash penetration tended to be larger in these areas and island breaching was common, leaving the surface close to the watertable and covered by a lag of shell and gravel. In contrast, large foredunes and the backbarrier dunes were observed at the widest sections of the island (the cuspate headlands) and at crest of the transverse ridges. Due to the large dunes and the presence of the backbarrier dunes, these areas experienced less overwash penetration and most of the sediment from the beachface and dunes was deposited within the upper-shoreface. It is argued that this sediment is returned to the beachface through nearshore bar migration following the storm and that the areas with larger foredunes and backbarrier dunes have smaller rates of historical shoreline erosion compared to areas with smaller dunes and greater transfer of sediment to the washover terrace. Since the recovery of the dunes will vary depending on the availability of sediment from the washover and beachface, it is further argued that the alongshore pattern of dune morphology and the response of the island to the next extreme storm is forced by the transverse ridges and island width through alongshore variations in storm surge and overwash gradients respectively. These findings may be particularly important for coastal managers involved in the repair and rebuilding of coastal infrastructure that was damaged or destroyed during Hurricane Ivan. ?? 2008 Elsevier B.V. All rights reserved.

Houser, C.; Hapke, C.; Hamilton, S.

2008-01-01

131

Environmental Impact Statement Truckee Meadows Flood Control Project  

E-print Network

DRAFT Environmental Impact Statement for the Truckee Meadows Flood Control Project Nevada General 2013 #12;#12;DRAFT Environmental Impact Statement for the Truckee Meadows Flood Control Project Nevada

US Army Corps of Engineers

132

Erosion can be a problem in many airfield areas. Erosion and sedimentation affect  

E-print Network

Erosion can be a problem in many airfield areas. Erosion and sedimentation affect local water develop a storm water pollution prevention plan (SWPPP) incorporating best management practices for erosion control at airports. Erosion is caused when soil is washed away by wind or water, resulting

Minnesota, University of

133

A Statistical Project Control Tool for Engineering Managers  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the use of a Statistical Project Control Tool (SPCT) for managing engineering projects. A literature review pointed to a definition of project success, (i.e., A project is successful when the cost, schedule, technical performance, and quality satisfy the customer.) The literature review also pointed to project success factors, and traditional project control tools, and performance measures that are detailed in the report. The essential problem is that with resources becoming more limited, and an increasing number or projects, project failure is increasing, there is a limitation of existing methods and systematic methods are required. The objective of the work is to provide a new statistical project control tool for project managers. Graphs using the SPCT method plotting results of 3 successful projects and 3 failed projects are reviewed, with success and failure being defined by the owner.

Bauch, Garland T.

2001-01-01

134

Chemical and vegetative stabilization of soils: Laboratory and field investigations of new materials and methods for soil stabilization and erosion control  

Microsoft Academic Search

A survey was conducted on chemical stabilization of soils, and revegetation methods and materials for erosion control. Results of the study indicate that through chemical and vegetative stabilization of disturbed soils, sediment production can be reduced, fertile top soil preserved, and a more environmentally acceptable condition achieved after construction is completed.

W. R. Morrison; L. R. Simmons

1977-01-01

135

Soil erosion in Swaziland: A synthesis  

Microsoft Academic Search

The main conclusions of the research project on soil erosion and sedimentation in Swaziland are as follows. (1) Soil erosion has worsened over the last 20 years. The proportion of an 1800 km2 study area in the Middleveld classified as ‘high erosion class’ has increased from 6.7 to 13.6% between 1972 and 1990. (2) Gully erosion is the main process

P. Felix-Henningsen; R. P. C. Morgan; H. M. Mushala; R. J. Rickson; T. Scholten

1997-01-01

136

Beach Erosion  

NSDL National Science Digital Library

This Why Files article considers beach erosion. Topics covered are: the nature and extent of beach losses, the role of beaches in protecting coasts, some measures -good and bad- to prevent coastal erosion, predicted effects of global warming and sea-level changes on beaches and the impact of melting ice sheets on global ocean volume. Some glaciologists using new calculations, think that instead of possibly collapsing in 100 years, as was considered possible 10 years ago, that the West Antarctic Ice Sheet is more likely to collapse in perhaps 5,000 years at the soonest. Five scientists were interviewed for this article.

Tenenbaum, David

1999-07-22

137

Erosion control technology: a user's guide to the use of the Universal Soil Loss Equation at waste burial facilities  

Microsoft Academic Search

The Universal Soil Loss Equation (USLE) enables the operators of shallow land burial sites to predict the average rate of soil erosion for each feasible alternative combination of plant cover and land management practices in association with a specified soil type, rainfall pattern, and topography. The equation groups the numerous parameters that influence erosion rate under six major factors, whose

J. W. Nyhan

1986-01-01

138

Greenidge Multi-Pollutant Control Project  

SciTech Connect

The Greenidge Multi-Pollutant Control Project was conducted as part of the U.S. Department of Energy's Power Plant Improvement Initiative to demonstrate an innovative combination of air pollution control technologies that can cost-effectively reduce emissions of SO{sub 2}, NO{sub x}, Hg, acid gases (SO{sub 3}, HCl, and HF), and particulate matter from smaller coal-fired electric generating units (EGUs). There are about 400 units in the United States with capacities of 50-300 MW that currently are not equipped with selective catalytic reduction (SCR), flue gas desulfurization (FGD), or mercury control systems. Many of these units, which collectively represent more than 55 GW of installed capacity, are difficult to retrofit for deep emission reductions because of space constraints and unfavorable economies of scale, making them increasingly vulnerable to retirement or fuel switching in the face of progressively more stringent environmental regulations. The Greenidge Project sought to confirm the commercial readiness of an emissions control system that is specifically designed to meet the environmental compliance requirements of these smaller coal-fired EGUs by offering a combination of deep emission reductions, low capital costs, small space requirements, applicability to high-sulfur coals, mechanical simplicity, and operational flexibility. The multi-pollutant control system includes a NO{sub x}OUT CASCADE{reg_sign} hybrid selective non-catalytic reduction (SNCR)/in-duct SCR system for NO{sub x} control and a Turbosorp{reg_sign} circulating fluidized bed dry scrubbing system (with a new baghouse) for SO{sub 2}, SO{sub 3}, HCl, HF, and particulate matter control. Mercury removal is provided as a co-benefit of the in-duct SCR, dry scrubber, and baghouse, and by injection of activated carbon upstream of the scrubber, if required. The multi-pollutant control system was installed and tested on the 107-MW{sub e}, 1953-vintage AES Greenidge Unit 4 by a team including CONSOL Energy Inc. as prime contractor, AES Greenidge LLC as host site owner, and Babcock Power Environmental Inc. as engineering, procurement, and construction contractor. About 44% of the funding for the project was provided by the U.S. Department of Energy, through its National Energy Technology Laboratory, and the remaining 56% was provided by AES Greenidge. Project goals included reducing high-load NO{sub x} emissions to {le} 0.10 lb/mmBtu; reducing SO{sub 2}, SO{sub 3}, HCl, and HF emissions by at least 95%; and reducing Hg emissions by at least 90% while the unit fired 2-4% sulfur eastern U.S. bituminous coal and co-fired up to 10% biomass. This report details the final results from the project. The multi-pollutant control system was constructed in 2006, with a total plant cost of $349/kW and a footprint of 0.4 acre - both substantially less than would have been required to retrofit AES Greenidge Unit 4 with a conventional SCR and wet scrubber. Start-up of the multi-pollutant control system was completed in March 2007, and the performance of the system was then evaluated over an approximately 18-month period of commercial operation. Guarantee tests conducted in March-June 2007 demonstrated attainment of all of the emission reduction goals listed above. Additional tests completed throughout the performance evaluation period showed 96% SO{sub 2} removal, 98% mercury removal (with no activated carbon injection), 95% SO{sub 3} removal, and 97% HCl removal during longer-term operation. Greater than 95% SO{sub 2} removal efficiency was observed even when the unit fired high-sulfur coals containing up to 4.8 lb SO{sub 2}/mmBtu. Particulate matter emissions were reduced by more than 98% relative to the emission rate observed prior to installation of the technology. The performance of the hybrid SNCR/SCR system was affected by problems with large particle ash, ammonia slip, and nonideal combustion characteristics, and high-load NO{sub x} emissions averaged 0.14 lb/mmBtu during long-term operation. Nevertheless, the system has reduced the unit's overall NO{sub x} emiss

Daniel Connell

2008-10-18

139

Field studies of beach cones as coastal erosion control/reversal devices for areas with significant oil and gas activities  

SciTech Connect

A field demonstration/study of a novel shoreline erosion protection device called beach cones is planned. These patented, fiberglass- reinforced concreted devices are to be deployed in a number of geometric patterns at seven location in the Bastian Bay area of Western Plaquemines Parish. The purpose of the work described in this report was to evaluate the proposed study's impact on living and non-living shellfish resources within each of the project's seven separate Study Areas. Major accomplishments for this reporting period were as follows: aerial photographs of the experimental sites were taken; all permit applications were filed; information was submitted for the Environmental Report; several reconnaissance trips to the experimental sites were made; meetings were held among all participating organizations to further plan the research; permit was obtained from the US Army Corps of Engineers; test sites were surveyed by the Xavier University contingent; survey data were taken at all sites; the Oyster Assessment was completed; permit was obtained from the State of Louisiana Department of Natural Resources; and initial survey data were finalized at all sites.

Not Available

1992-07-17

140

Factors controlling the spatial distribution of soil piping erosion on loess-derived soils: A case study from central Belgium  

NASA Astrophysics Data System (ADS)

Collapsible loess-derived soils are prone to soil piping erosion, where enlargement of macropores may lead to a subsurface pipe network and eventually to soil collapse and gully development. This study aims at understanding the main factors controlling spatial patterns of piping in loess-derived soils under a temperate climate. To map the spatial distribution of piping and identify the environmental controls on its distribution, a regional survey was carried out in a 236 km 2 study area in the Flemish Ardennes (Belgium). Orthophotos taken at optimal field conditions (winter) were analyzed to detect piping in open landscapes and ground thruthing was systematically done through field surveys. In total, 137 parcels having 560 collapsed pipes were mapped. Dimensions of the sinkholes and local slope gradient were measured in the field and topographical variables were derived from LiDAR data. Land use plays an important role as 97% of the sites with piping are found under pasture. The probability of piping increases rapidly on hillslopes with gradients exceeding 8% and with a concave profile and plan curvature, enhancing subsurface flow concentration. The zones with soil profiles on shallow loess over a relatively thin layer of homogeneous blue massive clays (Aalbeke Member) are most prone to piping. Soil characteristics are of less importance to explain piping occurrence. Furthermore, the topographical threshold line indicating the critical slope gradient for a given contributing drainage area was determined. This threshold line (negative power relation) is similar to the threshold line for shallow gully initiation.

Verachtert, E.; Van Den Eeckhaut, M.; Poesen, J.; Deckers, J.

2010-06-01

141

Analysis/control of in-bed tube erosion phenomena in the fluidized bed combustion (FBC) system. Technical progress report No. 4, [July 1, 1993--September 30, 1993  

SciTech Connect

This technical report Summarizes the research work performed and progress achieved during the period of July 1, 1993 to September 30, 1993. Design and fabrication of the electrostatic impact probe were continued for measuring particle-tube collision frequency in the bench-scale FBC model. To verify the working principle of the electrostatic impact probe and to establish the reliability of probe readings, several readings were performed. The number of impact particles can be conveniently read from the frequency counter by the impact probe, which was reproducible and consistent data. The erosion measurement was conducted under different superficial fluidizing velocity in the bench-scale FBC model. Results of specific weight loss versus excess air velocity (air velocity above the minimum fluidization velocity) show the dominant effect of the fluidizing velocity on the tube erosion. The project has been progressing well. Measurement of the particle-tube collision frequency will be conducted under different tube location by the electrostatic impact probe. Instrumentation for the measurement of the in-bed tube erosion will be continued under various operating conditions. In addition to that, the relationship between the results of particle-tube collision frequency and the measurement of in-bed tube erosion will be predicted.

Lee, Seong W.

1993-11-01

142

ECONOMIC IMPACTS OF SELECTED EROSION CONTROL POLICIES: DISTRIBUTION AMONG CORN BELT STATES  

EPA Science Inventory

If states in the Corn Belt adopt varying soil loss limits as a part of a nonpoint source of water pollution control program will there be adverse economic consequences. If so, what types of impacts would be felt and would they be severe. The objective of this analysis was focused...

143

Modeling the air traffic controller's cognitive projection process  

E-print Network

Cognitive projection enables the operator of a supervisory control system, such as air traffic control, to use predicted future behavior of the system to make decisions about if and how to control the system. New procedures ...

Reynolds, Hayley J. Davison (Hayley Jaye Davison)

2006-01-01

144

Erosion in Rivers  

NSDL National Science Digital Library

Students learn about water erosion through an experimental process in which small-scale buildings are placed along a simulated riverbank to experience a range of flooding conditions. They learn how soil conditions are important to the stability or failure of civil engineering projects and how a river's turns and bends (curvature, sinuosity) make a difference in the likelihood of erosion. They make model buildings either with a 3D printer or with LEGO® pieces and then see how their designs and riverbank placements are impacted by slow (laminar) and fast (turbulent) water flow over the soil. Students make predictions, observations and conclusions about the stability of their model houses, and develop ideas for how to mitigate damage in civil engineering projects.

AMPS GK-12 Program,

145

Erosion and Sediment Damages and Economic Impacts of Potential 208 Controls: A Summary of Five Watershed Studies in Texas  

E-print Network

This report summarizes results of economic analyses of erosion and sedimentation in five agricultural watersheds in Texas (see fig. 1). Economic analyses of the study areas considered both the on-farm economics of soil conservation and the economic...

Taylor, C. R.; Reneau, D. R.; Harris, B. L.

146

DA9601 for erosive gastritis: Results of a double-blind placebo-controlled phase III clinical trial  

Microsoft Academic Search

AIM: To determine the efficacy and safety of DA-9601 on erosive gastritis versus cetraxate as a standard drug by gastrointestinal endoscopy. METHODS: Five hundred and twelve patients with erosive gastritis were divided into three groups. The groups received 180 mg or 360 mg of DA-9601, or 600 mg of cetraxate (NeuerTM) t.i.d. for 2 wk, respectively. Endoscopic observations were performed

Sang Yong Seol; Myung Hwan Kim; Jong Sun Ryu; Myung Gyu Choi; Dong Wook Shin; Byoung Ok Ahn

147

Project Design Concept for Monitoring and Control System  

SciTech Connect

This Project Design Concept represents operational requirements established for use in design the tank farm Monitoring and Control System. These upgrades are included within the scope of Project W-314, Tank Farm Restoration and Safe Operations.

MCGREW, D.L.

2000-10-02

148

Using Thermochronology to Understand Orogenic Erosion  

E-print Network

Using Thermochronology to Understand Orogenic Erosion Peter W. Reiners and Mark T. Brandon, geomorphology, tectonics Abstract Erosion of orogenic mountain ranges exhumes deeply buried rocks and controls weathering, climate, and sediment production and transport at a variety of scales. Erosion also affects

Jellinek, Mark

149

Controlled Ecological Life Support System Breadboard Project - 1988  

NASA Technical Reports Server (NTRS)

The Controlled Ecological Life Support System (CELSS) Breadboard Project, NASA's effort to develop the technology required to produce a functioning bioregenerative system, is discussed. The different phases of the project and its current status are described. The relationship between the project components are shown, and major project activities for fiscal years 1989-1993 are listed. The biomass production chamber to be used by the project is described.

Knott, W. M.

1989-01-01

150

Application of video-cameras for quality control and sampling optimisation of hydrological and erosion measurements in a catchment  

NASA Astrophysics Data System (ADS)

Long term soil erosion studies imply substantial efforts, particularly when there is the need to maintain continuous measurements. There are high costs associated to maintenance of field equipment keeping and quality control of data collection. Energy supply and/or electronic failures, vandalism and burglary are common causes of gaps in datasets, reducing their reach in many cases. In this work, a system of three video-cameras, a recorder and a transmission modem (3G technology) has been set up in a gauging station where rainfall, runoff flow and sediment concentration are monitored. The gauging station is located in the outlet of an olive orchard catchment of 6.4 ha. Rainfall is measured with one automatic raingauge that records intensity at one minute intervals. The discharge is measured by a flume of critical flow depth, where the water is recorded by an ultrasonic sensor. When the water level rises to a predetermined level, the automatic sampler turns on and fills a bottle at different intervals according to a program depending on the antecedent precipitation. A data logger controls the instruments' functions and records the data. The purpose of the video-camera system is to improve the quality of the dataset by i) the visual analysis of the measurement conditions of flow into the flume; ii) the optimisation of the sampling programs. The cameras are positioned to record the flow at the approximation and the gorge of the flume. In order to contrast the values of ultrasonic sensor, there is a third camera recording the flow level close to a measure tape. This system is activated when the ultrasonic sensor detects a height threshold, equivalent to an electric intensity level. Thus, only when there is enough flow, video-cameras record the event. This simplifies post-processing and reduces the cost of download of recordings. The preliminary contrast analysis will be presented as well as the main improvements in the sample program.

Lora-Millán, Julio S.; Taguas, Encarnacion V.; Gomez, Jose A.; Perez, Rafael

2014-05-01

151

OPTIMAL CONTROL OF PROJECTS BASED ON KALMAN FILTER APPROACH FOR TRACKING & FORECASTING THE PROJECT PERFORMANCE  

E-print Network

to follow the original schedule or plan, inadvertently increasing the overall project cost. Many deterministic project control methods have been proposed by various researchers for calculating optimal resource schedules considering the time-cost as well...

Bondugula, Srikant

2010-07-14

152

The evolution of soft solutions for coastal erosion control: A study of the development of inflatable sand & water-filled geotextile devices  

SciTech Connect

The Dutch people are the first known to have employed sand-filled containers in erosion control. The myriad of enormous dikes surrounding Holland provide continuous protection to a nation which is sited largely below sea level. The earliest fabric material used in containment of sand for the construction of dikes and levees was a burlap type material which had severe limitations. The problem has been primarily related to the inadequacies of the fabric materials containing the sand fill. A comparable analogy exists in the aerospace industry. Incredible achievements in high speed flight which have been accomplished in the last thirty years were previously impossible due to the inadequacies of the aircraft construction materials available in the first half of the twentieth century. It is of particular interest to note that many of the {open_quotes}Space Age{close_quote} materials originally conceived through these initial alliances were later incorporated by entrepreneurs and private industry into applications and products far beyond the initial scope of their creators. The combination of high strength materials such as woven multifilament dacron thread, extrusion coated with poly vinyl chloride (PVC Plastic) has resulted in the development of heretofore unknown materials known as {open_quotes}Geotextiles{close_quotes}. Geotextile materials are high strength fabrics which have been specifically created for use in, on, under and around the earth. They incorporate exceptional strength with unique abrasion, puncture and ultraviolet resistance characteristics previously not available. The application of these space age geotextiles in the field of coastal erosion control has resulted in the development of a multitude of patented sand and water-filled erosion control devices which provide significant levels of storm protection for coastal homes and properties. This paper reviews the evolutionary development of sand and water filled systems for erosion control.

Sample, J.W.

1996-05-01

153

Effect of erosion-control structures on sediment and nutrient transport, Edgewood Creek drainage, Lake Tahoe basin, Nevada, 1981-83  

USGS Publications Warehouse

Three sites in the Edgewood Creek basin with a combined drainage area of about 1.2 sq mi were selected to assess the effect of erosion-control structures along Nevada State Highway 207, on sediment and nutrient transport. The flow at site one is thought to have been largely unaffected by urban development, and was completely unaffected by erosion control structures. The flow at site two was from a basin affected by urban development and erosion control structures. Site three was downstream from the confluence of streams measured at sites one and two. Most data on streamflow and water quality were collected between June 1981 and May 1983 to assess the hydrologic characteristics of the three sites. As a result of the erosion control structures, mean annual concentrations of total sediment were reduced from about 24,000 to about 410 mg/l at site two and from about 1,900 to about 190 ml/l at site three. Sediment loads were reduced from about 240 to about 10 tons/year at site two and from about 550 to about 110 tons/year at site three. At site one, in contrast, mean concentrations and loads remained low throughout the study period. At site two, sediment particle size changed from predominately coarse prior to construction, to predominately fine thereafter; at site three, it changed from about half coarse sediments to predominately fine. Mean concentration and loads of total iron also were significantly reduced after construction at sites two and three, whereas mean concentrations of nitrogen and phosphorus species did not change appreciably. (Author 's abstract)

Garcia, K. T.

1988-01-01

154

Response of stream macroinvertebrate assemblages to erosion control structures in a wastewater dominated urban stream in the southwestern U.S  

Microsoft Academic Search

Effects of stream erosion control structures on aquatic macroinvertebrates were studied (2000–2009) in a wastewater dominated\\u000a drainage (Wash) in Las Vegas, Nevada. Mainstem sites with and without structures, wastewater treatment plant outfalls, a reference\\u000a site above treatment plant inputs, and tributary sites were sampled. Ordination suggested hydrology and channel characteristics\\u000a (current velocity, stream depth, and width), and water quality (conductivity)

S. Mark Nelson

2011-01-01

155

Coprates Erosion  

NASA Technical Reports Server (NTRS)

4 June 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layered, light-toned, sedimentary rocks that have been exposed by erosion in Coprates Chasma, one of the many chasms which comprise the Valles Marineris trough system on Mars.

Location near: 13.1oS, 65.0oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Autumn

2006-01-01

156

Beach erosion rates and the National Flood Insurance Program  

NASA Astrophysics Data System (ADS)

Thirty of the nation's 50 states have coastlines on the Atlantic and Pacific oceans, the Gulf of Mexico, and the Great Lakes. These 30 states contain approximately 85% of the nation's population, and about half of this population resides in the coastal zone. Continued population growth is projected in the future, with a greatly increasing demand for beachfront development. At present, there is considerable public concern over coastal erosion, erosion control measures, and land use regulations [National Research Council, 1990].Beach erosion is a significant and growing national problem. The National Shoreline Study, conducted by the U.S. Army Corps of Engineers in 1971, was the first national appraisal of shore erosion problems. Significant erosion was found to occur along 43% of the U.S. shoreline if Alaska is excluded. Other large sections of sandy shoreline are also eroding, but the U.S. Army Corps of Engineers categorized it as noncritical erosion largely because of the lack of immediate threat to buildings and infrastructure at that time.

Leatherman, Stephen P.; Dean, Robert G.

157

Administrative Leadership as Projection, Social Control, and Action.  

ERIC Educational Resources Information Center

Over the past 50 years, theoretical and methodological problems have plagued the study of leadership. This paper, proposing an alternative theory, argues that leadership has three fundamental components: projection and social control, which are linked by action. Projection is the visualization of a project to be completed. Educational…

Reed, Donald B.

158

Self-Correcting HVAC Controls Project Final Report  

SciTech Connect

This document represents the final project report for the Self-Correcting Heating, Ventilating and Air-Conditioning (HVAC) Controls Project jointly funded by Bonneville Power Administration (BPA) and the U.S. Department of Energy (DOE) Building Technologies Program (BTP). The project, initiated in October 2008, focused on exploratory initial development of self-correcting controls for selected HVAC components in air handlers. This report, along with the companion report documenting the algorithms developed, Self-Correcting HVAC Controls: Algorithms for Sensors and Dampers in Air-Handling Units (Fernandez et al. 2009), document the work performed and results of this project.

Fernandez, Nicholas; Brambley, Michael R.; Katipamula, Srinivas; Cho, Heejin; Goddard, James K.; Dinh, Liem H.

2010-01-04

159

Insitu measurement of bedrock erosion  

NASA Astrophysics Data System (ADS)

While long term erosion rates may be estimated by dating methods, current day erosion rates are - if at all available - based on rough estimates or on point measurements. Precise quantification of short term erosion rates are required to improve our understanding of short term processes, for input in landscape evolution models, as well as for studying the mechanics and efficiency of different erosion processes in varying geomorphological settings. Typical current day erosion rates in the European Alps range from sub-millimetre to several millimetres per year depending on the dominant erosion processes. The level of surveying accuracy required for recurring sub-millimetre to millimetre measurements in the field is demanding. A photogrammetric technique was developed to measure surface changes on the bedrock samples. For field tests three bedrock samples of different lithology were installed in a debris flow channel (Illgraben in Switzerland). Samples were placed in a bed of concrete and fixed to a check dam already present in the flow channel. The expected erosion rate in this channel was assumed to allow for recurrent measurements after single debris flow events. Control points providing an absolute reference frame and were embedded in the concrete next to the bedrock samples. Results and experiences after two years of monitoring will be presented. While the methodology was able to provide data with the desired resolution and sub-millimetre accuracy in the field, further tests will be needed for optimization of the methodology itself as well as for an independent measurement of the ground control points.

Rieke-Zapp, D.

2012-04-01

160

Working with Farmers: The Key to Adoption of Vetiver Grass Hedgerows to Control Erosion in Cassava Fields in Thailand  

Microsoft Academic Search

Cassava (Manihot esculenta Crantz) is the third most important food crop in southeast Asia and the most important upland crop in the northeast of Thailand. The crop is usually grown by small holders in marginal areas of sloping or undulating land. Most farmers realize, however, that cassava production on slopes can cause severe erosion, while production without fertilizers or manure

Reinhardt Howeler; Watana Watananonta; Wilawan Vongkasem; Kaival Klakhaeng; Somjate Jantawat; Supha Randaway; Banyat Vankaew

161

Tectonic and climatic controls on rift escarpments: Erosion and flexural rebound of the Dhofar passive margin (Gulf of Aden, Oman)  

Microsoft Academic Search

We investigate the respective roles of climatic parameters and the flexural rigidity of the lithosphere in the erosion history and behavior of two adjacent rift escarpments along the northern coast of the Gulf of Aden, in Oman. At this 25 Myr old passive margin, we define a type 1 scarp, which is high, sharp-crested and has retreated 25–30 km inland

C. Petit; M. Fournier; Y. Gunnell

2007-01-01

162

Assessing soil erosion and control factors by radiometric technique in the source region of the Yellow River, Tibetan Plateau  

NASA Astrophysics Data System (ADS)

Measurements of 137Cs concentration in soils were made in a representative catchment to quantify erosion rates and identify the main factors involved in the erosion in the source region of the Yellow River in the Tibetan Plateau. In order to estimate erosion rates in terms of the main factors affecting soil loss, samples were collected taking into account the slope and vegetation cover along six selected transects within the Dari County catchment. The reference inventory for the area was established at a stable, well-preserved, site of small thickness (value of 2324 Bq·m- 2). All the sampling sites had been eroded and 137Cs inventories varied widely in the topsoil (14.87-25.56 Bq·kg- 1). The effective soil loss values were also highly variable (11.03-28.35 t·km- 1·yr- 1) in line with the vegetation cover change. The radiometric approach was useful in quantifying soil erosion rates and examining patterns of soil movement.

Wang, Yibo; Niu, Fujun; Wu, Qingbai; Gao, Zeyong

2014-05-01

163

MILA Antenna Control Unit Replacement Project  

NASA Technical Reports Server (NTRS)

The Air to Ground Subsystem (AGS) Antenna Control Units at the MILA Ground Network Tracking Station are at end-of-life and are being replaced. AGS consists of two antennas at MILA (Quad-Helix and Teltrac). Software was taken from the existing Subsystem Controller and modified for the Antenna Control Unit (ACU). The software is capable of receiving and sending commands to and from the ACU. Moving the azimuth clockwise, counterclockwise, moving the elevation up or down, turning servo power on and off, and inputting azimuth and elevation angles are commands that the antenna can receive.

Bresette, Jeremy

2007-01-01

164

Project W-049H instrument and control Acceptance Test Procedure  

SciTech Connect

The purpose of this Acceptance Test Procedure (ATP) for the Project W-049H, Treated Effluent Disposal Facility, is to verify that the instrument and control systems have been installed in accordance with the design documents and function as required by the project criteria. The instrument and control system includes three operator control stations, modems, and general purpose LAN interface cabinets in the Effluent Treatment Facility control room; two pump stations; disposal station pumping building; and all local control units installed in the fold. Testing will be performed using actual signals when available and simulated signals when actual signals are unavailable.

Carrigan, M.C.

1994-11-16

165

DIVISION OF DRUG ABUSE CONTROL A Project Evaluation  

E-print Network

L,: . -'" -- . : NARCONON 1/1 DIVISION OF DRUG ABUSE CONTROL FA-48-72 74-007 75-009 A Project. In Relation to the Stated Objectives of the Division of Drug Abuse Control's Application .......... II ........·..··.· Appendix C - NARCONON - Division of Drug Abuse Control Contract ..·.............·..... Appendix D - Job

Touretzky, David S.

166

Efficacy and safety of esomeprazole compared with omeprazole in GERD patients with erosive esophagitis: a randomized controlled trial  

Microsoft Academic Search

OBJECTIVE:In patients with gastroesophageal reflux disease (GERD), esomeprazole, the S-isomer of omeprazole, has demonstrated pharmacological and clinical benefits beyond those seen with the racemic parent compound. This study was designed to further evaluate the efficacy and tolerability of esomeprazole relative to that of omeprazole in healing erosive esophagitis and resolving accompanying symptoms of GERD.METHODS:Esomeprazole 40 mg was compared with omeprazole

Joel E Richter; Peter J Kahrilas; John Johanson; Paul Maton; Jeffrey R Breiter; Clara Hwang; Victoria Marino; Bernard Hamelin; Jeffrey G Levine

2001-01-01

167

Soil erosion in a man-made landscape: the Mediterranean  

NASA Astrophysics Data System (ADS)

Mediterranean-type ecosystems are characterised by a seasonally contrasted distribution of precipitation, by the coincidence of the driest and hottest season in summer, by an often-mountainous terrain, and by a long history of intense human occupation, especially around the Mediterranean Sea. The history of the Mediterranean lands is the history of human impacts on the soil system, and soil erosion is the most intense and widespread impact on this land where high intensity and uneven rainfall is found. A review of the soil erosion rates measured in the Mediterranean basin will be shown. The measurements done by means of erosion pins, topographical measurements, rainfall simulators, Gerlach collectors in open or close plots, watershed/basin measurements, reservoirs siltation and historical data will be shown. A review of the soil erosion models applied in the Mediterranean will be shown. The tentative approach done until October 2011 show that the soil erosion rates on Mediterranean type ecosystems are not as high as was supposed by the pioneers in the 70's. And this is probably due to the fact that the soils are very shallow and sediments are not available after millennia of high erosion rates. This is related to the large amount of rock fragments are covering the soil, and the rock outcrops that are found in the upper slope trams and the summits. Soil erosion in the Mediterranean is seasonal due to the rainfall concentration in winter, and highly variable within years as the high intensity rainfall events control the sediment production. Natural vegetation is adapted to the Mediterranean environmental conditions, and they are efficient to control the soil losses. An example are the forest fire that increase the soil losses but this is a temporal change as after 2-4 years the soil erosion rates are similar to the pre-fire period. Agriculture lands are the source of sediments although the highest erosion rates are found in badland areas that cover a small part of the Mediterranean lands. The methods applied to measure or estimate the soil erosion should be improved to make them comparable. An agreement is necessary to decide the size of the plots, the material and equipment to be used and the future research topics. This research study is being supported by the the research project CGL2008-02879/BTE

Cerdà, A.; Ruiz Sinoga, J. D.; Cammeraat, L. H.

2012-04-01

168

A case for wind enhanced tectonics: Plio-Quaternary sedimentation, erosion, and structural evolution controlled by wind within the Qaidam Basin, China  

NASA Astrophysics Data System (ADS)

The interplay between tectonics and localized erosion through fluvial and/or glacial processes has been widely documented. Wind erosion, however, has gone largely un-recognized as a potentially important process in this concept. We document an acceleration in shortening in response to wind deflation above actively deforming fault propagation anticlines since ~3.0 Ma in the Qaidam Basin, China. Evidence for this comes from a 1750 m measured section along the southwestern flank of an intra-basin anticline (38.33°N, 93.46°E) and regional cross-sections. Magnetostratigraphy provides age control for prominent stratigraphic and isotopic changes within the section. A positive shift of ~6‰ in the ?18O values of lake carbonates occurs at 1090 m (3.1 Ma), interpreted to be the result of increased aridity at that time. An intraformational angular unconformity, associated with anticline growth, appears at 1172 m (3.0 Ma) and records the initiation of growth strata deposition. At 1235 m (2.6 Ma), a marked lithofacies change to sub-aerial, evaporitic conditions is observed, and is associated with a 3-fold reduction in sedimentation rate. Paleo-yardangs, which are wind-eroded landforms preserved in the stratigraphic record, appear at 1260 m (2.4 Ma). These observations indicate that regional aridification at 3.1 Ma was followed closely by or coincident with fold growth. Facies changes to more evaporitic strata and erosion of the basin floor (based on paleo-yardangs) trailed initial climate and tectonic changes by 500,000-700,000 years. Although the on-lap relationship of post-growth strata implies that syn-tectonic strata may have pinched-out along the flanks of the anticline, our new analysis indicates that at least 1172 m of pre-growth strata must have been eroded from the core of the anticline since 3.0 Ma at a time-averaged rate of ~0.4 mm/year, comparable to fluvial and glacial erosion rates within active tectonic settings. The lack of an integrated fluvial channel network along the flank of the anticline suggests that all material has been removed by wind. There is no evidence for wind-erosion or substantial intra-basin deformation prior to 3.0 Ma, implying a rapid increase in erosion coincident with fold growth. In addition, all intra-basin anticlines, including the one targeted in this study, are crescent-shaped in map view and actively propagating northward, approximately perpendicular to and windward of the long-term surface wind-direction defined by active and buried yardangs. We suggest that rock uplift above the actively deforming fault propagation folds facilitated focused wind erosion along the windward, northerly flanks of the folds, and caused preferential material advection and the north-vergent anticlinal forms. Together, our data imply that regional climate change pre-dates or was synchronous with growth of the intra-basin folds, and that increased wind erosion after 3.0 Ma induced more rapid rock uplift and deflation along fold crests.

Heermance, R. V.; Kapp, P. A.; Pullen, A.; Garzione, C. N.

2012-12-01

169

Projection Operator: A Step Towards Certification of Adaptive Controllers  

NASA Technical Reports Server (NTRS)

One of the major barriers to wider use of adaptive controllers in commercial aviation is the lack of appropriate certification procedures. In order to be certified by the Federal Aviation Administration (FAA), an aircraft controller is expected to meet a set of guidelines on functionality and reliability while not negatively impacting other systems or safety of aircraft operations. Due to their inherent time-variant and non-linear behavior, adaptive controllers cannot be certified via the metrics used for linear conventional controllers, such as gain and phase margin. Projection Operator is a robustness augmentation technique that bounds the output of a non-linear adaptive controller while conforming to the Lyapunov stability rules. It can also be used to limit the control authority of the adaptive component so that the said control authority can be arbitrarily close to that of a linear controller. In this paper we will present the results of applying the Projection Operator to a Model-Reference Adaptive Controller (MRAC), varying the amount of control authority, and comparing controller s performance and stability characteristics with those of a linear controller. We will also show how adjusting Projection Operator parameters can make it easier for the controller to satisfy the certification guidelines by enabling a tradeoff between controller s performance and robustness.

Larchev, Gregory V.; Campbell, Stefan F.; Kaneshige, John T.

2010-01-01

170

MINE WASTE TECHNOLOGY PROGRAM - UNDERGROUND MINE SOURCE CONTROL DEMONSTRATION PROJECT  

EPA Science Inventory

This report presents results of the Mine Waste Technology Program Activity III, Project 8, Underground Mine Source Control Demonstration Project implemented and funded by the U. S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U. S. Department of E...

171

Supporting the Future Air Traffic Control Projection Process  

E-print Network

In air traffic control, projecting what the air traffic situation will be over the next 30 seconds to 30 minutes is a key process in identifying conflicts that may arise so that evasive action can be taken upon discovery ...

Davison, H. J.

2003-01-01

172

Soil and Sediment Erosion  

NSDL National Science Digital Library

This brief article discusses the effect of soil and sediment erosion and its significance in social and economic aspects. The methods of measuring erosion and knowledge of past erosion rates are also briefly discussed to use as a predictor of future erosion rates.

2008-09-22

173

SOIL EROSION AND PRODUCTIVITY  

E-print Network

SOIL EROSION AND PRODUCTIVITY DICK WOLKOWSKI DEPARTMENT OF SOIL SCIENCE UW-MADISON #12;SOIL EROSION/a/yr 30% OF US FARMLAND ABANDONED EROSION SALINIZATION WATER-LOGGING 90% OF US CROPLAND LOSING SOIL FASTER THAN IT IS REPLACED >1 t/a/yr PIMENTEL ET AL., 1995 #12;SOIL EROSION WATER AND WIND LOSSES CAN

Balser, Teri C.

174

Erosion control blankets, organic amendments and site variability influenced the initial plant community at a limestone quarry in the Canadian Rocky Mountains  

NASA Astrophysics Data System (ADS)

Season of seeding and soil amendment with manure mix, wood shavings and erosion control blankets were evaluated over two growing seasons to determine their effect on soil properties and native grass establishment at a Canadian limestone quarry and lime processing plant. Season (fall, spring) of soil amending and seeding did not significantly affect revegetation or soil properties. Site characteristics such as slope, aspect, initial soil nutrients and surrounding plant communities influenced early plant community development and overall effects of soil treatments. Erosion control blankets resulted in the highest seeded plant cover and the lowest non seeded plant cover despite not significantly changing soil chemical properties. Total nitrogen and carbon significantly increased establishment of seeded grasses and non seeded species. Increased nitrogen and carbon in the constructed soils were best achieved through addition of manure. Wood shavings did not favour establishment of vegetation and resulted in similar, and in some cases less, vegetation than controls. Assisted revegetation increased plant cover from < 6 to 50% and reduced cover of non seeded species. Amendments that modified both chemical and physical soil conditions were best to increase vegetation establishment in the harsh conditions of the quarry.

Cohen-Fernández, A. C.; Naeth, M. A.

2013-02-01

175

Erosion control blankets, organic amendments and site variability influenced the initial plant community at a limestone quarry in the Canadian Rocky Mountains  

NASA Astrophysics Data System (ADS)

Season of seeding and soil amendment with manure mix, wood shavings and erosion control blankets were evaluated over two growing seasons to determine their effect on soil properties and native grass establishment at a Canadian limestone quarry and lime processing plant. A season (fall, spring) of soil amending and seeding did not significantly affect revegetation or soil properties. Site characteristics such as slope, aspect, initial soil nutrients and surrounding plant communities influenced early plant community development and overall effects of soil treatments. Erosion control blankets resulted in the highest seeded plant cover and the lowest non-seeded plant cover despite not significantly changing soil chemical properties. Total nitrogen and carbon significantly increased establishment of seeded grasses and non-seeded species. Increased nitrogen and carbon in the constructed soils were best achieved through addition of manure. Wood shavings did not favour establishment of vegetation and resulted in similar, and in some cases less, vegetation than the controls. Assisted revegetation increased plant cover from < 6 to 50% and reduced cover of non-seeded species. Amendments that modified both chemical and physical soil conditions were best to increase vegetation establishment in the harsh conditions of the quarry.

Cohen-Fernández, A. C.; Naeth, M. A.

2013-07-01

176

Wind Erosion Research  

NSDL National Science Digital Library

Wind Erosion Research (WER) provides science-based wind erosion technology for environmentally, economically, and socially sustainable agriculture in the United States. This website introduces the Wind Erosion Equation (WEQ), the first model for estimating soil loss by wind from agricultural fields and the newly developed Wind Erosion Prediction System (WEPS) which provides new capabilities assessing plant damage and calculating suspension loss. Simulation models, multimedia archive and history of wind erosion research are available for educators and students.

2006-02-27

177

Validating and improving interrill erosion equations.  

PubMed

Existing interrill erosion equations based on mini-plot experiments have largely ignored the effects of slope length and plot size on interrill erosion rate. This paper describes a series of simulated rainfall experiments which were conducted according to a randomized factorial design for five slope lengths (0.4, 0.8, 1.2, 1.6, and 2 m) at a width of 0.4 m, five slope gradients (17%, 27%, 36%, 47%, and 58%), and five rainfall intensities (48, 62.4, 102, 149, and 170 mm h(-1)) to perform a systematic validation of existing interrill erosion equations based on mini-plots. The results indicated that the existing interrill erosion equations do not adequately describe the relationships between interrill erosion rate and its influencing factors with increasing slope length and rainfall intensity. Univariate analysis of variance showed that runoff rate, rainfall intensity, slope gradient, and slope length had significant effects on interrill erosion rate and that their interactions were significant at p?=?0.01. An improved interrill erosion equation was constructed by analyzing the relationships of sediment concentration with rainfall intensity, slope length, and slope gradient. In the improved interrill erosion equation, the runoff rate and slope factor are the same as in the interrill erosion equation in the Water Erosion Prediction Project (WEPP), with the weight of rainfall intensity adjusted by an exponent of 0.22 and a slope length term added with an exponent of -0.25. Using experimental data from WEPP cropland soil field interrill erodibility experiments, it has been shown that the improved interrill erosion equation describes the relationship between interrill erosion rate and runoff rate, rainfall intensity, slope gradient, and slope length reasonably well and better than existing interrill erosion equations. PMID:24516624

Zhang, Feng-Bao; Wang, Zhan-Li; Yang, Ming-Yi

2014-01-01

178

Validating and Improving Interrill Erosion Equations  

PubMed Central

Existing interrill erosion equations based on mini-plot experiments have largely ignored the effects of slope length and plot size on interrill erosion rate. This paper describes a series of simulated rainfall experiments which were conducted according to a randomized factorial design for five slope lengths (0.4, 0.8, 1.2, 1.6, and 2 m) at a width of 0.4 m, five slope gradients (17%, 27%, 36%, 47%, and 58%), and five rainfall intensities (48, 62.4, 102, 149, and 170 mm h?1) to perform a systematic validation of existing interrill erosion equations based on mini-plots. The results indicated that the existing interrill erosion equations do not adequately describe the relationships between interrill erosion rate and its influencing factors with increasing slope length and rainfall intensity. Univariate analysis of variance showed that runoff rate, rainfall intensity, slope gradient, and slope length had significant effects on interrill erosion rate and that their interactions were significant at p?=?0.01. An improved interrill erosion equation was constructed by analyzing the relationships of sediment concentration with rainfall intensity, slope length, and slope gradient. In the improved interrill erosion equation, the runoff rate and slope factor are the same as in the interrill erosion equation in the Water Erosion Prediction Project (WEPP), with the weight of rainfall intensity adjusted by an exponent of 0.22 and a slope length term added with an exponent of ?0.25. Using experimental data from WEPP cropland soil field interrill erodibility experiments, it has been shown that the improved interrill erosion equation describes the relationship between interrill erosion rate and runoff rate, rainfall intensity, slope gradient, and slope length reasonably well and better than existing interrill erosion equations. PMID:24516624

Zhang, Feng-Bao; Wang, Zhan-Li; Yang, Ming-Yi

2014-01-01

179

Field studies of beach cones as coastal erosion control/reversal devices for areas with significant oil and gas activities. [Annual report], February 24, 1992--February 23, 1993  

SciTech Connect

The primary objective of this project is to evaluate the utility of a device called the ``beach cone`` in combating coastal erosion. Seven initial sites were selected for testing beach cones in a variety of geometric configurations. Permits were obtained from the State of Louisiana and the US Army Corps of Engineers to perform the work associated with this study. Six hundred beach cones were actually installed at six of the sites in late July and early August, 1992. One of the initial sites was abandoned because it was found to be unsuitable for beach cone placement. The test sites have been observed for six months and preliminary findings indicate that beach cones accreted significant amounts of materials along the beach of a barrier island. At other test sites, accretion rates have been less dramatic but importantly, no significant additional erosion has occurred, which is a positive result. It is too soon to state the categorical success of the beach cones, but results to date are encouraging.

Law, V.J.

1993-03-15

180

Project: Driver and controller for a thermoelectric cooler  

E-print Network

Project: Driver and controller for a thermoelectric cooler Supervisor: Prof. Sam Ben-Yaakov Year solutions. Based on one of the three thermoelectric phenomena ­ the Peltier effect ­ bi-directional control is achieved. The TEC (which is a Thermoelectric Cooler) uses this effect. The direction of the current through

181

ANG coal gasification project management control system report. [Great Plains project  

SciTech Connect

Much time, money and effort has been spent in the forefront of this project for project controls. The work breakdown structure for the systems has been custom designed. The systems, both manual and computerized, have been well scrutinized and chosen by ANG to represent the most cost effective and efficient way of controlling a project the magnitude of $1.5 billion. These systems have been developed in a manner so that information can be gathered as detailed or as summarized as necessary, and in the most timely and expeditious ways.

Not Available

1981-01-01

182

Gully erosion and environmental change: importance and research needs  

Microsoft Academic Search

Assessing the impacts of climatic and, in particular, land use changes on rates of soil erosion by water is the objective of many national and international research projects. However, over the last decades, most research dealing with soil erosion by water has concentrated on sheet (interrill) and rill erosion processes operating at the (runoff) plot scale. Relatively few studies have

J Poesen; J Nachtergaele; G Verstraeten; C Valentin

2003-01-01

183

Overview of NASA's Thermal Control System Development for Exploration Project  

NASA Technical Reports Server (NTRS)

NASA's Constellation Program includes the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, are manned space vehicles while the third element is broader and includes several sub-elements including Rovers and a Lunar Habitat. The upcoming planned missions involving these systems and vehicles include several risks and design challenges. Due to the unique thermal environment, many of these risks and challenges are associated with the vehicles' thermal control system. NASA's Exploration Systems Mission Directorate (ESMD) includes the Exploration Technology Development Program (ETDP). ETDP consists of several technology development projects. The project chartered with mitigating the aforementioned risks and design challenges is the Thermal Control System Development for Exploration Project. The risks and design challenges are addressed through a rigorous technology development process that culminates with an integrated thermal control system test. The resulting hardware typically has a Technology Readiness Level (TRL) of six. This paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing assessments for thermal control system fluids.

Stephan, Ryan A.

2010-01-01

184

Overview of NASA's Thermal Control Technology Development Project  

NASA Technical Reports Server (NTRS)

NASA?s Constellation Program included the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, were planned to be manned space vehicles while the third element was much broader and included several sub-elements including Rovers and a Lunar Habitat. The planned missions involving these systems and vehicles included several risks and design challenges. Due to the unique thermal operating environment, many of these risks and challenges were associated with the vehicles? thermal control system. NASA?s Exploration Technology Development Program (ETDP) consisted of several technology development projects. The project chartered with mitigating the aforementioned thermal risks and design challenges was the Thermal Control System Development for Exploration Project. These risks and design challenges were being addressed through a rigorous technology development process that was planned to culminate with an integrated thermal control system test. Although these Constellation elements have been cancelled or significantly changed, the thermal technology development process is being continued within a new program entitled Enabling Technology Development and Demonstration (ETDD). The current paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing a material compatibility assessment for a promising thermal control system working fluid. The to-date progress and lessons-learned from these development efforts will be discussed throughout the paper.

Stephan, Ryan A.

2010-01-01

185

F-15 837 IFCS Intelligent Flight Control System Project  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews the use of Intelligent Flight Control System (IFCS) for the F-15. The goals of the project are: (1) Demonstrate Revolutionary Control Approaches that can Efficiently Optimize Aircraft Performance in both Normal and Failure Conditions (2) Advance Neural Network-Based Flight Control Technology for New Aerospace Systems Designs. The motivation for the development are to reduce the chance and skill required for survival.

Bosworth, John T.

2007-01-01

186

Apollo Soyuz Test Project photographic processing control plan  

NASA Technical Reports Server (NTRS)

The laboratory controls to be used within the photographic technology division (PTD) for processing original space flight films exposed on the Apollo Soyuz Test Project mission are specified. The sensitometric exposures to be used by PTD for certifying processes, for exposing Houston Controls, and for preflight and postflight exposures on original films as well as procedures for film certification are described. Processing conditions used to achieve each control and processing machine operating parameters are included.

Lockwood, H. E.

1975-01-01

187

Management of sediment and erosion processes in boreal headwaters affected by peatland drainage  

NASA Astrophysics Data System (ADS)

Peatland drainage for forestry, agriculture, peat harvesting and urban infrastructure has been altered landscape in Finland. Pristine peatlands and headwaters provide important hydrological and ecological functions that can be lost after drainage. The drainage has resulted in increase of forest resources but also negative environmental effects including changes in runoffs, erosion processes, siltation and eutrophication. The changes that can occur after drainage are, however, complex and must be better understood if the negative impacts of drainage are to be reduced or prevented. Especially erosion and transport processes of organic peat sediment are not well understood (Marttila and Kløve, 2008). Methods for controlling the sediment load include erosion and transport control practices in the catchment area (Marttila and Kløve, 2009; Tammela et al. 2009). The presentation/poster will present methods and preliminary results project from Northern Finland. The issues especially covered are sediment erosion and transport and methods to restore and reduce impacts of peatland drainage in boreal headwaters. Keywords: sediment transport, erosion, peatland drainage, organic and inorganic sediment, stream and catchment restoration, management, environment References: Marttila, H. and Kløve. B. 2008. Erosion and delivery of deposited peat sediment. Water Resources Research. 44 (6). Marttila, H. Kløve. B. 2009. Retention of sediment and nutrient loads with peak runoff control. Journal of Irrigation and Drainage Engineering (in press). Tammela, S. Marttila, H. and Kløve. B. 2009. Effect and design of an underminer structure on flow distribution and local bed topography (submitted).

Marttila, H.; Tammela, S.; Kløve, B.

2009-04-01

188

Corticothalamic Projections Control Synchronization in Locally Coupled Bistable Thalamic Oscillators  

NASA Astrophysics Data System (ADS)

Thalamic circuits are able to generate state-dependent oscillations of different frequencies and degrees of synchronization. However, little is known about how synchronous oscillations, such as spindle oscillations in the thalamus, are organized in the intact brain. Experimental findings suggest that the simultaneous occurrence of spindle oscillations over widespread territories of the thalamus is due to the corticothalamic projections, as the synchrony is lost in the decorticated thalamus. In this Letter we study the influence of corticothalamic projections on the synchrony in a thalamic network, and uncover the underlying control mechanism, leading to a control method which is applicable for several types of oscillations in the central nervous system.

Mayer, Jörg; Schuster, Heinz Georg; Claussen, Jens Christian; Mölle, Matthias

2007-08-01

189

EPRI condenser-related research projects  

Microsoft Academic Search

This special report summarizes the research projects EPRI has funded through 1981 relating to steam surface condensers in electric power plants. Divided into sections according to the type of issue addressed, the first section presents general projects identifying causes of condenser failures. The following sections deal with studies on air and water in leakage control, erosion-corrosion control, leak detection, biofouling

M. Laliberte; J. Bartz; W. Chow; I. Diaz-Tous; I. Murarka; W. Childs; R. Coit; T. Law; J. Quinn; B. Syrett

1981-01-01

190

CLEAR LAKE BASIN 2000 PROJECT  

SciTech Connect

The following is a final report for the Clear Lake Basin 2000 project. All of the major project construction work was complete and this phase generally included final details and testing. Most of the work was electrical. Erosion control activities were underway to prepare for the rainy season. System testing including pump stations, electrical and computer control systems was conducted. Most of the project focus from November onward was completing punch list items.

LAKE COUNTY SANITATION DISTRICT

2003-03-31

191

Mechanisms of polymer degradation and erosion  

Microsoft Academic Search

The most important features of the degradation and erosion of degradable polymers in vitro are discussed. Parameters of chemical degradation, which is the scission of the polymer backbone, are described such as the type of polymer bond, pH and copolymer composition. Examples are given how these parameters can be used to control degradation rates. Degradation leads finally to polymer erosion,

Achim Göpferich

1996-01-01

192

THE SWIRL CONCENTRATOR FOR EROSION RUNOFF TREATMENT  

EPA Science Inventory

A device for the partial removal of erosion products in stormwater runoff has been developed. The swirl concentrator as an erosion control device has been designed to concentrate the heavier soils from large flows. The concentrated underflow of up to 14 percent of the flow can be...

193

Rainfall profile characteristics in erosive and not-erosive events  

NASA Astrophysics Data System (ADS)

In a storm the rainfall rate shows fluctuations with showers, low rain periods or rainless periods that follow one another at short or long time intervals. The intra-storm rainfall variations and event profile have been proved to have an important influence and exert a fundamental control in many field and research areas among which in runoff generation and soil erosion (Dunkerley, 2012; Frauenfeld and Truman, 2004; Mermut et al., 1997; Parsons and Stone 2006; Ran et al, 2012; Watung et al. 1996;). In particular the possibility to incorporate into simulated rain events pre-determined intensity variations, have recently driven more investigation on the effect of further intra-storm properties on the hydrograph and on the soil loss dynamic such as the position among the rainfall of the maximum rainfall intensity and of the rainless intervals (Dunkerley, 2008, 2012; El-Jabi and Sarraf, 1991; Parsons and Stone 2006; Ran et al, 2012). The objective of this paper is to derive the statistical expressions for the time distribution of erosive and not-erosive rainfalls and to describe the rainfall factors that influence the time distribution characteristics and that characterize an erosive event compared to a not erosive event. The analysis is based on the database of the experimental site of Masse (Central Italy): event soil loss and runoff volume from bare plot and climatic data, at 5 min time interval for the 5-years period 2008-2012 (Bagarello et al., 2011, Todisco et al., 2012). A total of 228 rainfall events were used in which the rainfall exceed 1 mm, 60 of which erosive. The soil is a Typic Haplustept (Soil Survey Staff, 2006) with a silty-clay-loam texture. The runs theory (Yevjevich, 1967) were applied to the rainfall events hyetograph to select the heavier ones named storms. The sequential periods with rainfall intensity above a threshold are defined as heavy intensity in series and called runs. All the rainfall events characterized by at least one run were considered as a heavy storm and included in the analysis. The rainfall event is defined as a sequence of rainless and rainy periods defined as burst. The statistical expressions for the time distribution of erosive and not-erosive rainfalls were derived and the rainfall factors that influence the time distribution characteristics and that characterize an erosive event compared to a not erosive event were identified. The time distribution of erosive and not erosive storms have been expressed as cumulative percentages of storm rainfall and storm duration to make valid comparisons between storms and to simplify analysis presentation of data. The time distribution models presented as probability distributions, provide quantitative measures of both the inter-storm variability and the general characteristics of the time sequence of precipitation in storms. Other characteristics derived and analyzed, that are pertinent in classification of storms, include the number and the duration of individual runs in the total storm period, the total severity of the runs, the location of the heaviest run in the storm period, the percentage of the total storm period that had occurred at the start and end of this run, the percentage of the total storm rainfall preceding the heaviest run, the percentage of the total storm rainfall occurring at the heaviest run, the percentage of total storm rainfall occurring at the shower that contain the heaviest run, the percentage of the total storm period during which rain actually fell. The results obtained should aid the hydrologist in design problems or other application such as: the design of experiments for soil erosion study corresponding with the comparable measures of natural events (Agassi et al., 1999; Dunkerley, 2008; Kinnell, 2005; Mathys et al., 2005;) both in intra-storm dynamic and overall characteristics (Hanke et al., 2004); or the extrapolation of the erosive event inter-storm characteristics in which the time distribution is a pertinent factor.

Todisco, Francesca

2014-05-01

194

Erosion in Our World  

NSDL National Science Digital Library

This activity is a field investigation where students find real-life examples of erosion in their school surroundings. Students will extend what they learned during stream table lessons about erosion, deposition, deltas, meandering streams, and dams.

Payeur, Abbey

195

Project Management Using Modern Guidance, Navigation and Control Theory  

NASA Technical Reports Server (NTRS)

Implementing guidance, navigation, and control (GN&C) theory principles and applying them to the human element of project management and control is not a new concept. As both the literature on the subject and the real-world applications are neither readily available nor comprehensive with regard to how such principles might be applied, this paper has been written to educate the project manager on the "laws of physics" of his or her project (not to teach a GN&C engineer how to become a project manager) and to provide an intuitive, mathematical explanation as to the control and behavior of projects. This paper will also address how the fundamental principles of modern GN&C were applied to the National Aeronautics and Space Administration's (NASA) Constellation Program (CxP) space suit project, ensuring the project was managed within cost, schedule, and budget. A project that is akin to a physical system can be modeled and managed using the same over arching principles of GN&C that would be used if that project were a complex vehicle, a complex system(s), or complex software with time-varying processes (at times nonlinear) containing multiple data inputs of varying accuracy and a range of operating points. The classic GN&C theory approach could thus be applied to small, well-defined projects; yet when working with larger, multiyear projects necessitating multiple organizational structures, numerous external influences, and a multitude of diverse resources, modern GN&C principles are required to model and manage the project. The fundamental principles of a GN&C system incorporate these basic concepts: State, Behavior, Feedback Control, Navigation, Guidance and Planning Logic systems. The State of a system defines the aspects of the system that can change over time; e.g., position, velocity, acceleration, coordinate-based attitude, and temperature, etc. The Behavior of the system focuses more on what changes are possible within the system; this is denoted in the state of the system. The behavior of a system, as captured in the system modeling, when properly done will aid in accurately predicting future system performance. The Feedback Control system understands the state and behavior of the system and uses feedback to adjust control inputs into the system. The feedback, which is the right arm of the Control system, allows change to be affected in the overall system; it therefore is important to not only correctly identify the system feedback inputs, but also the system response to the feedback inputs. The Navigation system takes multiple data inputs and based on a priori knowledge of the inputs, develops a statistically based weighting of the inputs and measurements to determine the system's state. Guidance and Planning Logic of the system, complete with an understanding of where the system is (provided by the Navigation system), will in turn determine where the system needs to be and how to get it there. With any system/project, it is critical that the objective of the system/project be clearly defined -- not only to plan but to measure performance and to aid in guiding the system or the project. The system principles discussed above, which can be and have been applied to the current CxP space suit development project, can also be mapped to real-world constituents, thus allowing project managers to apply systems theories that are well defined in engineering and mathematics to a discipline (i.e., Project Management) that historically has been based in personal experience and intuition. This mapping of GN&C theory to Project Management will, in turn, permit a direct, methodical approach to Project Management, planning and control providing a tool to help predict (and guide) performance and an understanding of the project constraints, how the project can be controlled, and the impacts to external influences and inputs. This approach, to a project manager, flows down to the three bottom-line variables of cost, schedule, and scope ando the needed control of these three variables to successfully perform and complete a pr

Hill, Terry R.

2011-01-01

196

Overview of NASA's Thermal Control System Development for Exploration Project  

NASA Technical Reports Server (NTRS)

The now-cancelled Constellation Program included the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, were planned to be manned space vehicles while the third element was much more diverse and included several sub-elements. Among other things, these sub-elements were Rovers and a Lunar Habitat. The planned missions involving these systems and vehicles included several risks and design challenges. Due to the unique thermal operating environment, many of these risks and challenges were associated with the vehicles thermal control system. NASA s Exploration Technology Development Program (ETDP) consisted of various technology development projects. The project chartered with mitigating the aforementioned thermal risks and design challenges was the Thermal Control System Development for Exploration Project. These risks and design challenges were being addressed through a rigorous technology development process that was planned to culminate with an integrated thermal control system test. Although the technologies being developed were originally aimed towards mitigating specific Constellation risks, the technology development process is being continued within a new program. This continued effort is justified by the fact that many of the technologies are generically applicable to future spacecraft thermal control systems. The current paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing a material compatibility assessment for a promising thermal control system working fluid. The to-date progress and lessons-learned from these development efforts will be discussed throughout the paper.

Stephan, Ryan A.

2011-01-01

197

Advanced Guidance and Control Project for Reusable Launch Vehicles  

NASA Technical Reports Server (NTRS)

The goals of this project are to significantly reduce the time and cost associated with guidance and control design for reusable launch vehicles, and to increase their safety and reliability. Success will lead to reduced cycle times during vehicle design and to reduced costs associated with flying to new orbits, with new payloads, and with modified vehicles. Success will also lead to more robustness to unforeseen circumstances in flight thereby enhancing safety and reducing risk. There are many guidance and control methods available that hold some promise for improvement in the desired areas. Investigators are developing a representative set of independent guidance and control methods for this project. These methods are being incorporated into a high-fidelity off is being conducted across a broad range of flight requirements. The guidance and control methods that perform the best will have demonstrated the desired qualities.

Hanson, John M.

2000-01-01

198

PREDICTING MINESOIL EROSION POTENTIAL  

EPA Science Inventory

Two experimental plots were instrumented with erosion pins to study the correspondence between point erosion and erosion over an area on strip mine soil. Using a rotating boom rainfall simulator, data were collected by sampling the runoff every five minutes for the duration of th...

199

Runoff generation and soil erosion processes after clear-cuttings  

NASA Astrophysics Data System (ADS)

Timber harvesting by large scale clear-cut is known to impose environmental impact including severe disturbance of the soil-hydraulic properties which in turn intensify surface runoff and soil erosion in both frequency and magnitude. However, it remains unanswered if such clear-cut harvest areas act rather as sources or sinks for runoff and soil erosion and whether such behaviour is steady or dynamically alternating. For this purpose, 92 small scale rainfall simulations of different intensities were carried out under pine plantation conditions and on two clear-cut harvest areas of different age in the Chilean Coastal Range. Non-parametrical Random Forest statistical models were set up to quantify the impact of environmental variables on the hydrological and erosion response. The plot-scale responses were linked to observations at the catchment outlets. Against all expectations, infiltration rates slightly increased after logging while runoff initiated fastest and generated highest infiltration excess rates under plantation forest floor regardless of the applied rainfall intensity. Exceeding a threshold rainfall intensity of 20 mm/h, the clear-cut areas started to act as a source for both runoff and erosion after connectivity established while they remained a sink under lower applied rainfall intensities. Post-logging soil erosion increased by two orders of magnitude compared with unlogged conditions highlighting the importance of reforestation immediately after the timber harvest. The results suggest that surface runoff connectivity by overcoming microtopography restrictions, preferential flow along recent and former root systems and water repellence control runoff generation and soil erosion processes in such environments. Fast hydrological response to rainfall, sediment-discharge-hystereses and enhanced post-logging groundwater recharge at catchment scale support our interpretation. The persistent impact of timber harvest by clear-cut practice implies that inter-harvest periods of 24 years are too short to allow complete recovery of the initial soil-hydraulic conditions. The authors thank Project CONICYT-BMBF 243-2010.

Iroume, A.; Mohr, C. H.; Bronstert, A.; Huber, A.

2012-12-01

200

Field studies of beach cones as coastal erosion control/reversal devices for areas with significant oil and gas activities. Annual report, February 24, 1993--February 23, 1994  

SciTech Connect

The primary objective of this project was to evaluate the utility of a device called the ``beach cone`` in combating coastal erosion. Seven initial sites were selected for testing beach cones in a variety of geometric configurations, and six sites were actually used. Six hundred beach cones were installed at the six sites in late July and early August, 1992. An additional 109 cones were installed at an eighth site in December of 1992. Findings indicate that beach cones accreted significant amounts of materials along the beach of a barrier island. At the eighth installation the amount of accreted material was measured by surveys to be 2200 cubic meters (2900 cubic yards) in February of 1993, when the cones were found to have been completely covered by the material. The average increase in elevation was about 7 inches (0. 18 in) with a maximum buildup of 3 ft. (I in). At other test sites, accretion rates have been less dramatic but importantly, no significant additional erosion has occurred, which is a positive result. The cost of sediment accretion using beach cones was found to be about $13.72 per cubic yard of sand or approximately $500,000 per mile of beach, which would be much lower if the cones were mass produced. The survival of the cones through the fringes of Hurricane Andrew indicates that they can be anchored sufficiently to survive significant storms. The measurements of the cones settling rates indicate that this effect is negligible, does not hinder their effectiveness. We do not yet have sufficient data to state the categorical success of the beach cones, but results to date are encouraging.

Law, V.J.

1994-07-07

201

Environmental Impact Statement Truckee Meadows Flood Control Project  

E-print Network

DRAFT Environmental Impact Statement for the Truckee Meadows Flood Control Project Nevada General Reevaluation Report Volume I � Draft Environmental Impact Statement prepared by U.S. Army Corps of Engineers Sacramento District May 2013 #12;#12;DRAFT Environmental Impact Statement for the Truckee Meadows Flood

US Army Corps of Engineers

202

[Functions of different cultivation modes in oasis agriculture on soil wind erosion control and soil moisture conservation].  

PubMed

During 2001-2002, the effects of different cultivation modes including winter irrigation and zero tillage, crop-grass intercropping, and early spring film mulching on sand entrainment, wind velocity gradient and soil moisture conservation were studied in the middle reaches of the Heihe River in the Hexi Corridor region. The results showed that all these modes could reduce soil wind erosion and halt sand entrainment to different degrees. Compared with the bare fields exposed by spring plowing, early spring film mulching could increase soil moisture storage by 35.6%. At present, spring plowing and sowing was a main factor responsible to the occurrence of sand storms and the increase in suspended dust content. Farmlands in the upper and middle reaches of the Heihe River generally produced a dust transport up to 4.8-6.0 million tons per year, which was higher than that of sandy desert in the same region. In the Hexi Corridor region, the suspended dust amount produced from 1 hm2 farmland was equivalent to that of 1.5 hm2 desert. PMID:15669480

Su, Peixi; Zhao, Aifen; Du, Mingwu

2004-09-01

203

Thermochemical erosion  

NASA Technical Reports Server (NTRS)

A quasi-steady multidimensional Stefan problem is treated by means of similarity, asymptotic methods, and numerical analysis. The continuous wearing away of a solid 'erodee' is effected by gradual consumption of a solid 'eroder'. In the process under study, the erodee melts and the (liquid) melt diffuses to the eroder, where an exothermic, indefinitely rapid, diffusion-controlled surface reaction occurs. The products of reaction convey some of the chemically-generated heat to the surface of the erodee, so that further melting may occur, and the process may proceed. The analysis seeks to estimate the quasi-steady rates of consumption of the erodee and eroder, for the (convenient) self-similar case of confocal parabolas defining the boundaries of the melt layer. The analysis is simplified by observing that the flow is of lubrication-theory type: creeping, primarily unidirectional motion owing to the thinness of the melt layer between the erodee and eroder, with diffusion of heat and mass predominantly perpendicular to the principal motion. The analysis is completed by consideration of the force balance on the eroder.

Butler, Gerald; Fendell, Francis

1987-01-01

204

Project Management Using Modern Guidance, Navigation and Control Theory  

NASA Technical Reports Server (NTRS)

The idea of control theory and its application to project management is not new, however literature on the topic and real-world applications is not as readily available and comprehensive in how all the principals of Guidance, Navigation and Control (GN&C) apply. This paper will address how the fundamental principals of modern GN&C Theory have been applied to NASA's Constellation Space Suit project and the results in the ability to manage the project within cost, schedule and budget. A s with physical systems, projects can be modeled and managed with the same guiding principles of GN&C as if it were a complex vehicle, system or software with time-varying processes, at times non-linear responses, multiple data inputs of varying accuracy and a range of operating points. With such systems the classic approach could be applied to small and well-defined projects; however with larger, multi-year projects involving multiple organizational structures, external influences and a multitude of diverse resources, then modern control theory is required to model and control the project. The fundamental principals of G N&C stated that a system is comprised of these basic core concepts: State, Behavior, Control system, Navigation system, Guidance and Planning Logic, Feedback systems. The state of a system is a definition of the aspects of the dynamics of the system that can change, such as position, velocity, acceleration, coordinate-based attitude, temperature, etc. The behavior of the system is more of what changes are possible rather than what can change, which is captured in the state of the system. The behavior of a system is captured in the system modeling and if properly done, will aid in accurate system performance prediction in the future. The Control system understands the state and behavior of the system and feedback systems to adjust the control inputs into the system. The Navigation system takes the multiple data inputs and based upon a priori knowledge of the input, will develop a statistical-based weighting of the input to determine where the system currently is located. Guidance and Planning logic of the system with the understanding of where it is (provided by the navigation system) will in turn determine where it needs to be and how to get there. Lastly, the system Feedback system is the right arm of the control system to allow it to affect change in the overall system and therefore it is critical to not only correctly identify the system feedback inputs but also the system response to the feedback inputs. And with any systems project it is critical that the objective of the system be clearly defined for not only planning but to be used to measure performance and to aid in the guidance of the system or project.

Hill, Terry

2010-01-01

205

Links between erosion, runoff variability, and seismicity in the Taiwan orogen  

Microsoft Academic Search

Erosion of mountain belts controls their topographic and structural evolution and is the main source of sediment delivered to the oceans. While mountain erosion rates have been estimated from relief and precipitation, full evaluation of controls on erosion rates and patterns is challenging and requires detailed measurements across multiple time-scales. We report erosion rates in the Taiwan mountains estimated from

Simon J. Dadson; Niels Hovius; Hongey Chen; W. Brian Dade; Meng-Long Hsieh; Sean D. Willett; Jyr-Ching Hu; Ming-Jame Horng; Meng-Chiang Chen; Colin P. Stark; Dimitri Lague; Jiun-Chuan Lin

2003-01-01

206

The Application of the Vetiver System in Erosion Control and Stabilization for Highways Construction and Maintenance in Thailand  

Microsoft Academic Search

Since 1993, The Vetiver System (VS) has been applied both in construction and maintenance projects of mountain roads in the Northern , Northeastern , and Southern regions of Thailand. Over 2.5 million slips are planted each year. The Department of Highways (1994) has prepared a Standard Drawing (SP-204 1994 and SP-206 (Revision) 1999,\\

Surapol Sanguankaeo; Surachai Chaisintarakul; Ekawit Veerapunth

207

Education and the Professionalization of Nursing: Non-Collective Action and the Erosion of Labour-Market Control.  

ERIC Educational Resources Information Center

Between 1984-1989, following establishment of the United Kingdom Central Council for Nursing, Midwifery and Health Visiting, a reform-oriented, noncollective professional project emerged that marooned 30 percent of the nursing work force in an obsolescent occupational group. UKCC eroded nursing's labor-market position with the National Health…

Humphreys, John

2000-01-01

208

Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project  

SciTech Connect

General Motors, LLC and energy partner Shell Hydrogen, LLC, deployed a system of hydrogen fuel cell electric vehicles integrated with a hydrogen fueling station infrastructure to operate under real world conditions as part of the U.S. Department of Energy's Controlled Hydrogen Fleet and Infrastructure Validation and Demonstration Project. This technical report documents the performance and describes the learnings from progressive generations of vehicle fuel cell system technology and multiple approaches to hydrogen generation and delivery for vehicle fueling.

Stottler, Gary

2012-02-08

209

33 CFR 263.23 - Small flood control project authority (Section 205).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Small flood control project authority (Section 205). 263...DEFENSE CONTINUING AUTHORITIES PROGRAMS Flood Control Policy § 263.23 Small flood control project authority (Section 205)....

2010-07-01

210

Finite Convergence of a Subgradient Projections Method with Expanding Controls  

SciTech Connect

We study finite convergence of the modified cyclic subgradient projections (MCSP) algorithm for the convex feasibility problem (CFP) in the Euclidean space. Expanding control sequences allow the indices of the sets of the CFP to re-appear and be used again by the algorithm within windows of iteration indices whose lengths are not constant but may increase without bound. Motivated by another development in finitely convergent sequential algorithms that has a significant real-world application in the field of radiation therapy treatment planning, we show that the MCSP algorithm retains its finite convergence when used with an expanding control that is repetitive and fulfills an additional condition.

Censor, Yair, E-mail: yair@math.haifa.ac.il [University of Haifa, Department of Mathematics (Israel); Chen Wei, E-mail: chen.wei@mgh.harvard.edu [Massachusetts General Hospital and Harvard Medical School, Department of Radiation Oncology (United States); Pajoohesh, Homeira, E-mail: hpajoohesh@mec.cuny.edu [City University of New York, Department of Mathematics, Medgar Evers College (United States)

2011-10-15

211

NIF Projects Controls and Information Systems Software Quality Assurance Plan  

SciTech Connect

Quality achievement for the National Ignition Facility (NIF) and the National Ignition Campaign (NIC) is the responsibility of the NIF Projects line organization as described in the NIF and Photon Science Directorate Quality Assurance Plan (NIF QA Plan). This Software Quality Assurance Plan (SQAP) is subordinate to the NIF QA Plan and establishes quality assurance (QA) activities for the software subsystems within Controls and Information Systems (CIS). This SQAP implements an activity level software quality assurance plan for NIF Projects as required by the LLNL Institutional Software Quality Assurance Program (ISQAP). Planned QA activities help achieve, assess, and maintain appropriate quality of software developed and/or acquired for control systems, shot data systems, laser performance modeling systems, business applications, industrial control and safety systems, and information technology systems. The objective of this SQAP is to ensure that appropriate controls are developed and implemented for management planning, work execution, and quality assessment of the CIS organization's software activities. The CIS line organization places special QA emphasis on rigorous configuration control, change management, testing, and issue tracking to help achieve its quality goals.

Fishler, B

2011-03-18

212

Evaluation of the Serum Zinc Level in Erosive and Non-Erosive Oral Lichen Planus  

PubMed Central

Statement of Problem: Lichen planus is a chronic inflammatory immunologic-based disease involving skin and mucosa. This disease is generally divided into two categories: erosive and non-erosive. Many etiologic factors are deliberated regarding the disease; however, the disorders of immune system and the role of cytotoxic T-lymphocytes and monocytes are more highlighted. Zinc is an imperative element for the growth of epithelium and its deficiency induces the cytotoxic activity of T-helper2 cells, which seems to be associated with lichen planus. Purpose: This study was aimed to evaluate the levels of serum zinc in erosive and non-erosive oral lichen planus (OLP) and to compare it with the healthy control group to find out any feasible inference. Materials and Method: A total of 22 patients with erosive oral lichen planus, 22 patients with non erosive OLP and 44 healthy individuals as the control group were recruited in this descriptive-comparative study. All the participants were selected from the referees to the department of oral medicine, school of dentistry, Tabriz University of Medical Sciences. Serum zinc level was examined for all the individuals with liquid-stat kit (Beckman Instruments Inc.; Carlsbad, CA). Data were analyzed by adopting the ANOVA and Tukey tests, using SPSS 16 statistical software. Results: The mean age of patients with erosive and non-erosive LP was 41.7 and 41.3 years, respectively. The mean age of the healthy control group was 34.4 years .The mean serum zinc levels in the erosive and non erosive lichen planus groups and control groups were 8.3 (1.15), 11.15 (0.92) and 15.74 (1.75) ?g/dl respectively. The difference was statistically significant (p< 0.05). Conclusion: The serum zinc levels were decreased in patients with erosive oral lichen planus. This finding may probably indicate the promising role of zinc in development of oral lichen planus. PMID:24883340

Gholizadeh, N.; Mehdipour, M.; Najafi, Sh.; Bahramian, A.; Garjani, Sh.; Khoeini Poorfar, H.

2014-01-01

213

Soil Erosion Protection Potential of Young Paulownia Plantation  

NASA Astrophysics Data System (ADS)

Soil erosion is removal of soil and rock particles by water, wind, ice and gravity. It is widely recognized as a global soil threat. Soils impacted by different forms of erosion cover large areas around the world. While landscape, soil and climate conditions trigger soil erosion processes, the vegetation cover reduces the soil erosion risk. About 60 % of the area of agricultural land in Bulgaria is under erosion risk, which necessitates implementation of series of measures for soil erosion control. The aim of this study is to determine the erosion protection potential and the loss of soil nutrients of young Paulownia plantation. Field experiments have been set up under unirrigated conditions at the experimental field for soil erosion studies of the N. Poushkarov Institute of Soil Science, Agrotechnology and Plant Protection near Suhodol. The local soils are Chromic Luvisols, moderately eroded. The altitude is 750 m and the slope gradient is 80. The experiment consists of four field plots for soil erosion studies, three of which planted with Paulownia Bellissima and a reference one with bare soil. The plants have been planted at a distance of 2 m between adjacent rows and 1 m between each two plants within the row. The size of each field plot is 32 m2 (4 m width and 8 m length). The plots are equipped with containers for collecting the surface runoff caused by erosive rainfall events. Biometrics, including the root-striking of the plants, their growth in height, foliage cover (projection) and stem diameter, was studied from May 13th to October 21st. The data reported cover the results from the studies during the first vegetation period after planting in the Spring of 2013. During the year four erosive rainfalls were observed with a total amount of 79.2 mm, resulting to a total amount of soil loss of 772 kg/ha from a planted plot and 551 kg/ha from bear soil. The total surface runoff is 156.7 m3/ha from planted plot and 153.1 m3/ha from bare soil. The total losses of N-NO3- are 0.994 kg/ha from plated plots and 0.718 kg/ha from bare soils and the losses of N-NH4+ are respectively 0.042 and 0.117 kg/ha. The results from biometrics showed that 58 % of the plants were found to have stroken roots; an average growth of 0.3 m and a mean increase in the number of leaves with 3 were recorded. The results reported here show that the losses of soil and nutrients from the field plots planted with Paulownia Bellissima are about 40 % higher than these from the plot with bare soil. This discouraging result needs further experimental and theoretical analyses. The research throughout the following years will give further information about the soil erosion protection potential of young Paulownia plantation.

Stepchich, Avgusta; Djodjov, Christo

2014-05-01

214

Weathering and Erosion  

NSDL National Science Digital Library

In this multi-station lab, learners conduct a series of experiments to explore the processes and effects of weathering and erosion. Using the results from these explorations, learners design and conduct an experiment comparing the rate of erosion in different biomes. Use this activity to teach weathering and erosion, and also to illustrate how scientists often use the results of one experiment to inspire another. This activity is intended to be conducted over multiple meetings.

Whitfield, Lise

2010-01-01

215

Ecological-site based assessments of wind and water erosion: informing management of accelerated soil erosion in rangelands  

NASA Astrophysics Data System (ADS)

This work explores how soil erosion assessments can be structured in the context of ecological sites and site dynamics to inform systems for managing accelerated soil erosion. We evaluated wind and water erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Our results show that wind and water erosion can be highly variable within and among ecological sites. Plots in shrub-encroached and shrub-dominated states were consistently susceptible to both wind and water erosion. However, grassland plots and plots with a grass-succulent mix had a high indicated susceptibility to wind and water erosion respectively. Vegetation thresholds for controlling erosion are identified that transcend the ecological sites and their respective states. The thresholds define vegetation cover levels at which rapid (exponential) increases in erosion rates begin to occur, suggesting that erosion in the study ecosystem can be effectively controlled when bare ground cover is <20% of a site or total ground cover is >50%. Similarly, our results show that erosion can be controlled when the cover of canopy interspaces >50 cm in length reaches ~50%, the cover of canopy interspaces >100 cm in length reaches ~35% or the cover of canopy interspaces >150 cm in length reaches ~20%. This process-based understanding can be applied, along with knowledge of the differential sensitivity of vegetation states, to improve erosion management systems. Land use and management activities that alter cover levels such that they cross thresholds, and/or drive vegetation state changes, may increase the susceptibility of sites to erosion. Land use impacts that are constrained within the natural variability of sites should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds and natural variability of ecological sites will enable improved identification of where and when accelerated soil erosion occurs and the development of practical management solutions.

Webb, N.; Herrick, J.; Duniway, M.

2013-12-01

216

Preventing inadmissible erosion-corrosion thinning from occurring in the diffuser segments of feedwater supply control systems of power units at nuclear power stations equipped with RBMK-1000 reactors  

NASA Astrophysics Data System (ADS)

Results obtained from investigations of erosion-corrosion processes that occur during operation of the feedwater supply control systems used in power units of nuclear power stations equipped with RBMK-1000 reactors and the sensitivity of these processes to variations in the chemical composition of metal and in the flow path geometry are presented. It is found that local erosion-corrosion thinning of the walls in the diffuser segments of feedwater supply control systems occur mainly due to intense mass transfer in the near-wall region taken in combination with a low content of chromium. Hydrodynamic simulation was carried out, and it was shown based on its results that local erosion-corrosion thinning of the walls of pipeline segments downstream of the valves controlling the supply of feedwater to power units of nuclear power stations equipped with RBMK-1000 reactors can be prevented by subjecting them to appropriate modernization. It is found that the above mentioned diffuser parts can be made more resistant to erosion-corrosion wear by keeping the content of chromium in the main metal and weld joints at a level of no less than 0.25% and concurrently reducing the hydrodynamic effect in the zones of weld connections.

Tomarov, G. V.; Shipkov, A. A.; Golubeva, T. N.; Greblov, P. N.

2013-05-01

217

Greenridge Multi-Pollutant Control Project Preliminary Public Design Report  

SciTech Connect

The Greenidge Multi-Pollutant Control Project is being conducted as part of the U.S. Department of Energy's Power Plant Improvement Initiative to demonstrate an innovative combination of air pollution control technologies that can cost-effectively reduce emissions of SO{sub 2}, NO{sub x}, Hg, acid gases (SO{sub 3}, HCl, and HF), and particulate matter from smaller coal-fired electrical generating units (EGUs). The multi-pollutant control system includes a hybrid selective non-catalytic reduction (SNCR)/in-duct selective catalytic reduction (SCR) system to reduce NOx emissions by {ge}60%, followed by a Turbosorp{reg_sign} circulating fluidized bed dry scrubber system to reduce emissions of SO{sub 2}, SO{sub 3}, HCl, and HF by {ge}95%. Mercury removal of {ge}90% is also targeted via the co-benefits afforded by the in-duct SCR, dry scrubber, and baghouse and by injection of activated carbon upstream of the scrubber, as required. The technology is particularly well suited, because of its relatively low capital and maintenance costs and small space requirements, to meet the needs of coal-fired units with capacities of 50-300 MWe. There are about 440 such units in the United States that currently are not equipped with SCR, flue gas desulfurization (FGD), or mercury control systems. These smaller units are a valuable part of the nation's energy infrastructure, constituting about 60 GW of installed capacity. However, with the onset of the Clean Air Interstate Rule, Clean Air Mercury Rule, and various state environmental actions requiring deep reductions in emissions of SO{sub 2}, NO{sub x}, and mercury, the continued operation of these units increasingly depends upon the ability to identify viable air pollution control retrofit options for them. The large capital costs and sizable space requirements associated with conventional technologies such as SCR and wet FGD make these technologies unattractive for many smaller units. The Greenidge Project aims to confirm the commercial readiness of an emissions control system that is specifically designed to meet the environmental compliance requirements of these smaller coal-fired EGUs. The multi-pollutant control system is being installed and tested on the AES Greenidge Unit 4 (Boiler 6) by a team including CONSOL Energy Inc. as prime contractor, AES Greenidge LLC as host site owner, and Babcock Power Environmental Inc. as engineering, procurement, and construction contractor. All funding for the project is being provided by the U.S. Department of Energy, through its National Energy Technology Laboratory, and by AES Greenidge. AES Greenidge Unit 4 is a 107 MW{sub e} (net), 1950s vintage, tangentially-fired, reheat unit that is representative of many of the 440 smaller coal-fired units identified above. Following design and construction, the multi-pollutant control system will be demonstrated over an approximately 20-month period while the unit fires 2-4% sulfur eastern U.S. bituminous coal and co-fires up to 10% biomass. This Preliminary Public Design Report is the first in a series of two reports describing the design of the multi-pollutant control facility that is being demonstrated at AES Greenidge. Its purpose is to consolidate for public use all available nonproprietary design information on the Greenidge Multi-Pollutant Control Project. As such, the report includes a discussion of the process concept, design objectives, design considerations, and uncertainties associated with the multi-pollutant control system and also summarizes the design of major process components and balance of plant considerations for the AES Greenidge Unit 4 installation. The Final Public Design Report, the second report in the series, will update this Preliminary Public Design Report to reflect the final, as-built design of the facility and to incorporate data on capital costs and projected operating costs.

Daniel P. Connell

2009-01-12

218

Geomorphic considerations for erosion prediction  

USGS Publications Warehouse

Current soil-erosion prediction technology addresses processes of rainsplash, overland-flow sediment transport, and rill erosion in small watersheds. The effects of factors determining sediment yield from larger-scale drainage basins, in which sediment movement is controlled by the combined small-scale processes and a complex set of channel and other basin-scale sediment-delivery processes, such as soil creep, bioturbation, and accelerated erosion due to denudation of vegetation, have been poorly evaluated. General suggestions are provided for the development of erosion-prediction technology at the geomorphic or drainage-basin scale based on the separation of sediment-yield data for channel and geomorphic processes from those of field-scale soil loss. An emerging technology must consider: (1) the effects on sediment yield of climate, geology and soils, topography, biotic interactions with other soil processes, and land-use practices; (2) all processes of sediment delivery to a channel system; and (3) the general tendency in most drainage basins for progressively greater sediment storage in the downstream direction.

Osterkamp, W.R.; Toy, T.J.

1997-01-01

219

Project B610 process control configuration acceptance test procedure  

SciTech Connect

The purpose of this test is to verify the Westinghouse configuration of the MICON A/S Distributed Control System for project B610. The following will be verified: proper assignment and operation of all field inputs to and outputs from the MICON Termination panels; proper operation of all display data on the operator`s console; proper operation of all required alarms; and proper operation of all required interlocks. The MICON A/S control system is configured to replace all the control, indication, and alarm panels now located in the Power Control Room. Nine systems are covered by this control configuration, 2736-ZB HVAC, 234-5Z HVAC, Process Vacuum, Dry Air, 291-Z Closed Loop Cooling, Building Accelerometer, Evacuation Siren, Stack CAMs, and Fire. The 2736-ZB HVAC system consists of the ventilation controls for 2736-ZB and 2736-Z as well as alarms for the emergency generators and 232-Z. The 234-5Z HVAC system is the ventilation controls for 235-5Z and 236-Z buildings. Process Vacuum covers the controls for the 26 inch vacuum system. Dry Air covers the controls for the steam and electric air dryers. The 291-Z Closed Loop Cooling system consists of the status indications and alarms for the 291-Z compressor and vacuum pump closed loop cooling system. The rest of closed loop cooling was tested earlier. The Building Accelerometer system consists of the status indications for the two seismic system accelerometers. The Evacuation Siren system includes the controls for the evacuation and take cover sirens. Stack CAMs cover the alarms for the various building ventilation stack continuous air monitors. Finally, the Fire system covers the various fire alarms now located in Room 321-A.

Silvan, G.R.

1994-09-20

220

Impact of water control projects on fisheries resources in Bangladesh  

NASA Astrophysics Data System (ADS)

Bangladesh is a very flat delta built up by the Ganges—Brahmaputra—Meghna/Barak river systems. Because of its geographical location, floods cause huge destruction of lives and properties almost every year. Water control programs have been undertaken to enhance development through mitigating the threat of disasters. This structural approach to flood hazard has severely affected floodplain fisheries that supply the major share of protein to rural Bangladesh, as exemplified by the Chandpur Irrigation Project. Although the regulated environment of the Chandpur project has become favorable for closed-water cultured fish farming, the natural open-water fishery loss has been substantial. Results from research show that fish yields were better under preproject conditions. Under project conditions per capita fish consumption has dropped significantly, and the price of fish has risen beyond the means of the poor people, so that fish protein in the diet of poor people is gradually declining. Bangladesh is planning to expand water control facilities to the remaining flood-prone areas in the next 15 20 years. This will cause further loss of floodplain fisheries. If prices for closed-water fish remain beyond the buying power of the poor, alternative sources of cheap protein will be required.

Mirza, Monirul Qader; Ericksen, Neil J.

1996-07-01

221

Impact of Water Control Projects on Fisheries Resources in Bangladesh  

PubMed

Bangladesh is a very flat delta built up by the Ganges-Brahmaputra-Meghna/Barak river systems. Because of its geographical location, floods cause huge destruction of lives and properties almost every year. Water control programs have been undertaken to enhance development through mitigating the threat of disasters. This structural approach to flood hazard has severely affected floodplain fisheries that supply the major share of protein to rural Bangladesh, as exemplified by the Chandpur Irrigation Project. Although the regulated environment of the Chandpur project has become favorable for closed-water cultured fish farming, the natural open-water fishery loss has been substantial. Results from research show that fish yields were better under preproject conditions. Under project conditions per capita fish consumption has dropped significantly, and the price of fish has risen beyond the means of the poor people, so that fish protein in the diet of poor people is gradually declining. Bangladesh is planning to expand water control facilities to the remaining flood-prone areas in the next 15-20 years. This will cause further loss of floodplain fisheries. If prices for closed-water fish remain beyond the buying power of the poor, alternative sources of cheap protein will be required. PMID:8661619

Mirza; Ericksen

1996-07-01

222

Soil Erosion and Agricultural Sustainability  

Microsoft Academic Search

Data drawn from a global compilation of studies support the long articulated contention that erosion rates from conventionally plowed agricultural fields greatly exceed rates of soil production, erosion under native vegetation, and long-term geological erosion. Whereas data compiled from around the world show that soil erosion under conventional agriculture exceeds both rates of soil production and geological erosion rates by

D. R. Montgomery

2009-01-01

223

Erosion and Wind Deposition  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 22 April 2003

Streamlined buttes and mesas are left as remnants of an erosive wind that has carried away sediments and even the rim of a small crater. Two wind directions are apparent in the buttes and mesas that cross each other at 90 degrees. Small dark dunes wind their way between the remnant towers, indicating that the work of the wind is an ongoing process.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude 5.3, Longitude 350.1 East (9.9 West). 19 meter/pixel resolution.

2003-01-01

224

An investigation of the effect of hydrodynamics of flow on erosion-corrosion resistance of components of a feedwater control assembly used in power units of nuclear power plants equipped with RBMK-1000 reactors  

NASA Astrophysics Data System (ADS)

The results of computational hydrodynamic simulation of the flow of a working medium in the flow path of the feedwater control assembly used in power units of nuclear power plants (NPPs) equipped with the reactors of the RBMK-1000 type are presented It was established that the rate of control valve opening has an influence on the position of the areas of the intense local erosion-corrosion thinning of metal of the diffuser section downstream of the valve.

Tomarov, G. V.; Shipkov, A. A.; Golubeva, T. N.; Greblov, P. N.

2013-08-01

225

IT Project Governance: A Process-Oriented Study of Organizational Control and Executive Involvement  

Microsoft Academic Search

This paper reports on a study of organizational control of IT projects, specifically how control forms and evolves over time and how executives engage in the control task. Viewing executive involvement in its organizational context, the study builds on studies on executive involvement in IT (including top management support), IT project escalation and IS project control, while drawing upon theories

Magnus Mähring

2002-01-01

226

Project B610 process control configuration acceptance test report  

SciTech Connect

The purpose of this test is to verify the Westinghouse configuration of the MICON A/S Distributed Control System for project B610. The following will be verified: (1) proper assignment and operation of all field inputs to and outputs from the MICON Termination panels; (2) proper operation of all display data on the operators` console; (3) proper operation of all required alarms; and (4) proper operation of all required interlocks. This test only verifies the proper operation of the Westinghouse control configuration (or program). It will not be responsible for verifying proper operation of the MICON hardware or operating software. Neither does it test any of the B610 instrument. The MICON hardware and software has been tested as part of the equipment procurement. Instrumentation and wiring installed under project B620 will be tested under a separate functional test. In some cases, precise transmitter ranges, alarm setpoints, and controller tuning parameters are not available at this time. Therefore, approximate values are used during the test. This should not affect the proper operation of the configuration or the validity of this test. Final values will be assigned during operability testing.

Silvan, G.R.

1995-06-27

227

Hot Erosion of Glass.  

National Technical Information Service (NTIS)

In this paper the effect of plastic flow on the erosion of soda-lime-silicate glass at elevated temperatures is investigated. Although the erosion of glass at 500 C and 600 C is still basically a brittle process, viscous relaxation of glass during impact ...

S. M. Wiederhorn, B. J. Hockey

1980-01-01

228

Erosion and Weathering  

NSDL National Science Digital Library

Weathering and erosion work together as natural forces, removing and transporting material. Sediments, the by-products of these processes, are subsequently deposited to produce characteristic landforms such as dunes, deltas, and glacial moraines. This slide show presents images of landforms that result from erosion and weathering, as well as measures designed to mitigate their unwanted effects.

229

Coastal Erosion Online Discussion  

NSDL National Science Digital Library

The students are given the following: Read the articles below about erosion along the Lake Erie shoreline and discuss them. What causes the erosion? What can be done to prevent erosion? Should people be allowed to build structures to protect their property from erosion? Should people be allowed to live along the shoreline in high erosion areas? Students are expected to have completed the coastal erosion module (read text book, view powerpoint lecture and take a quiz) and read articles regarding coastal erosion along the Lake Erie coastline. In the online discussion, students must show that they understand coastal processes, the impact of man made structures on coastal processes, and can apply their values as they discuss what should be done, if anything, to reduce the impact of coastal erosion. Teaching Tips Adaptations that allow this activity to be successful in an online environment This was designed as an online activity. I have also used it in face-to-face courses (students participate in online discussion prior to in-class discussion). Elements of this activity that are most effective This gets students thinking about how what they learn in class can be used to solve real problems faced by the local community and/or the world. Although some students propose impractical solutions, they are at least thinking. Recommendations for other faculty adapting this activity to their own course: Find local issues and/or global issues that show how geology can be used to solve problems.

Roberts, Sheila

230

COASTAL INLET BANK EROSION  

Microsoft Academic Search

Much focus is placed on beach erosion on the open coast. However, coastal processes often occur on sandy shorelines interior to inlets that can lead to severe erosion. These shorelines lie adjacent to coastal inlets and extend around the inlet from the ocean to bay. In particular, an examination of coastal inlets with jetties or terminal groins that are connected

William C. Seabergh

2001-01-01

231

Erosion of a geopolymer.  

SciTech Connect

Solid-particle erosion studies were conducted on a representative geopolymer. The test conditions were normal impact of 390-{micro}m angular Al{sub 2}O{sub 3} erodent particles moving at 50, 70, or 100 m/s. Steady-state erosion rates were obtained and the material-loss mechanism was studied by scanning electron microscopy. The geopolymer responded as a classic brittle material. Elastic-plastic indentation events led to formation of brittle cleavage cracks that resulted in spallation of material. The erosion rate was proportional to erodent velocity to the 2.3 power. The erosion rate and mechanism for the geopolymer were nearly identical to what has been observed for erosion of Si single crystals.

Goretta, K. C.; Chen, N.; Routbort, J. L.; Lukey, G. C.; van Deventer, J. S. J.

2002-07-02

232

Plant materials and amendments for controlling wind and water erosion on a fly ash disposal area: TVA Colbert Fossil Plant, Alabama  

SciTech Connect

Fly ash disposal sites adjacent to fossil fueled generating plants are subject to wind and water erosion which increases the operation and maintenance costs. Gullies and unstable areas in the disposal sites require expensive leveling and filling practices. Test evaluated both warm- and cool-season cover crops established by either sod or seed. Amendments to the ash consisted of composted poultry litter (CPL), soil, soil+CPL, fertilizer and beneficial soil microbes including mycorrhizal fungi. Turf sods (419 Bermuda, Emerald zoysia, and Raleigh St. Augustine) were compared in greenhouse and field studies. Six legumes and 12 grass species were tested in the greenhouse as seeded cover crops using similar amendments and raw poultry litter (PL). Legumes grew better with CPL and Boil amendments and grasses grew better on PL and soil amendments possibly due to differences in N requirements and N supply. Cool season crops generally grew faster than warm season species in the greenhouse tests. Amendments should be mixed with the FA to ameliorate the effects of boron and salt toxicity and to increase the water holding capacity. Bermuda sod grew faster than either St, Augustine or Emerald zoysia, but requires more water. A microbial amendment increased dry matter yields of bermuda sod 2 to 3 times after 40 to 60 days over unamended controls. Microbial amendments may be justified on an economic and sustainable basis. A field study is assessing the environmental and cultural requirements to grow a cover crop on an annual basis.

Maddox, J.J.; Behel, D.; Soileau, J.M.; Kelsoe, J.

1996-12-31

233

The cost control of communication construction projects: Case study of Zhejiang Post and Telecommunication Construction Corporation  

Microsoft Academic Search

With the increasing competition of communication industry, how to improve the economic efficiency of construction project has been a very urgent task for the communication construction enterprises. This article first posts the importance of cost control in communication construction project. Then further applications are integrated in the cost control of construction projects to Taizhou project department in the sample enterprise,

Zheng Ye; Da-jia Mao

2011-01-01

234

CRCHD SPN Project: The Network for Cancer Control Research Among American Indian and Alaska Native Populations  

Cancer.gov

CRCHD SPN Project: The Network for Cancer Control Research Among American Indian and Alaska Native Populations  Back to CRCHD Completed Research SPN Project Listing The Network for Cancer Control Research Among American Indian and Alaska Native

235

WEPS and WEPP Science Commonality Project1  

Microsoft Academic Search

The United States Department of Agriculture, Agricultural Research Service (USDA-ARS) has two independently developed, daily time step, process-based erosion models, one targeted for wind erosion (WEPS - Wind Erosion Prediction System) and one targeted for water erosion (WEPP - Water Erosion Prediction Project). The models currently share little source code or soil, plant, management and climate databases but do simulate

F. A. Fox; D. C. Flanagan; L. E. Wagner; L. Deer-Ascough

236

Project impact analysis as an optimal control problem  

Microsoft Academic Search

This paper analyzes the effects of a major investment project on a multi-sector less developed economy. Single investment projects with external effects reaching across the entire economy are frequently encountered in developing countries. This study concentrates on the Mahaweli Ganga Development Project in Sri Lanka, a multi-dam irrigation and hydroelectric power project. The Mahaweli Project calls for an annual investment

Anandalingam

1981-01-01

237

Erosion of soil organic carbon: implications for carbon sequestration  

USGS Publications Warehouse

Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

Van Oost, K.; Van Hemelryck, H.; Harden, J.W.

2009-01-01

238

Controls on decadal erosion rates in Qilian Shan: Re-evaluation and new insights into landscape evolution in north-east Tibet  

NASA Astrophysics Data System (ADS)

Available data from the Qilian Shan in north-east Tibet suggested that decadal-scale erosion rates were closely correlated with local topographic gradient, but not with climatic factors. However, a climatic change to more arid condition was proposed to explain the discrepancy between short-term and long-term erosion rates. In order to re-evaluate the topographic, tectonic and climatic influences on erosion, we adopted five parameters (slope, mean local relief, historical cumulative seismic moment, runoff coefficient of variation and fault density) to study 11 drainage basins in north-east Tibet. Our results showed that terrain gradient, rock fracture density and rainstorm intensity had strong influence on erosion rates while 60-year cumulative seismic moments of historical earthquakes showed weaker correlations. There was a spatial variation in the erosional mechanisms across the basin, with detachment-limited dominance around the ridges (slope > 20°) and deposition dominant in the flat areas. The variation may lead to the discrepancy between short-term and long-term erosion rates. In general, our study supports the ‘bath-tub’ model for low relief intermountain basins, hence providing new insights into the landscape evolution of the Qilian Shan in northeastern Tibetan Plateau.

Yizhou, Wang; Huiping, Zhang; Dewen, Zheng; Wenjun, Zheng; Zhuqi, Zhang; Weitao, Wang; Jingxing, Yu

2014-10-01

239

Cause of Erosion Mitigation  

E-print Network

Different models for predicting erosion · USLE: Universal Soil Loss Equation ­ Most common (not necessarily) · 1965 completed USLE · RUSLE (revised) (~1998) · RUSLE2 (revised revised) (~2003) #12;01-5 (R)USLE

Boisvert, Jeff

240

Naked Dirt: Erosion  

NSDL National Science Digital Library

This file explains that the United States Department of Agriculture developed the Universal Soil Loss Equation (revised in 1993 to RUSLE) to help farmers, landscapers, and architects decide how to prevent erosion. The equation predicts the rate of erosion for a site based on the annual rainfall, soil type, and degree of slope. The site includes a table that shows how different practices affect erosion rates. It explains that sediment pollution makes swimming and boating less fun, clogs city drinking water systems, fills in lakes, and smothers fish and insect habitat. Sediments often float awhile before settling out, making water cloudy or turbid. There is an explanation of which native grasses are best for holding the soil in place and other suggestions to stop erosion.

241

Galveston Island and erosion  

E-print Network

protection. The 1970's and 1980's have seen the building of two new beachfront condominiums on East Beach and extensive housing subdivisions on west Galveston Island. Homecr aft Land Development (an affiliate of U. S. Homes), Mitchell Development Inc... problems in the future. Erosion is an old, continuing phenomenon on Galveston Island but most people do not seem concerned about it until they are directly im- pacted. PREVIOUS STUDIES I1any early studies concerning erosion and shoreline protection...

Bolleter, Jim Mason

2012-06-07

242

Management of a large distributed control system development project  

SciTech Connect

Building an accelerator at six geographically dispersed sites is quite mad, but politically expedient. The Spallation Neutron Source (SNS), currently under construction in Oak Ridge, Tennessee, combines a pulsed 1 Gev H{sup -} superconducting linac with a compressor ring to deliver 2 MW of beam power to a liquid mercury target for neutron production [1]. Accelerator components, target and experimental (neutron-scattering) instruments are being developed collaboratively by Lawrence Berkeley (Ion Source and Front End), Los Alamos (Linac), Thomas Jefferson (Cryosystems), Brookhaven (Compressor Ring), Oak Ridge (Target and Conventional Facilities) and Argonne (Neutron Scattering Instruments) National Laboratories. Similarly, a team distributed among all of the participating laboratories is developing the EPICS-based control system. this paper discusses the management model and strategies being used to address the unusual issues of organization, communication, standardization, integration and hand-off inherent in this widely-distributed project.

Gurd, D. P. (David P.)

2002-01-01

243

40 CFR 93.125 - Enforceability of design concept and scope and project-level mitigation and control measures.  

...project-level mitigation and control measures. 93.125 Section 93...project-level mitigation and control measures. (a) Prior to determining...project-level mitigation or control measures which are identified as...

2014-07-01

244

Spinal Projection Neurons Control Turning Behaviors in Zebrafish  

PubMed Central

Summary Discrete populations of brainstem spinal projection neurons (SPNs) have been shown to exhibit behavior-specific responses during locomotion [1–9], suggesting that separate descending pathways, each dedicated to a specific behavior, control locomotion. In an alternative model, a large variety of motor outputs could be generated from different combinations of a small number of basic motor pathways. We examined this possibility by studying the precise role of ventromedially located hindbrain SPNs (vSPNs) in generating turning behaviors. We found that unilateral laser ablation of vSPNs reduces the tail deflection and cycle period specifically during the first undulation cycle of a swim bout, whereas later tail movements are unaffected. This holds true during phototaxic [10], optomotor [11], dark-flash-induced [12], and spontaneous turns [13], suggesting a universal role of these neurons in controlling turning behaviors. Importantly, we found that the ablation not only abolishes turns but also results in a dramatic increase in the number of forward swims, suggesting that these neurons transform forward swims into turns by introducing turning kinematics into a basic motor pattern of symmetric tail undulations. Finally, we show that vSPN activity is direction specific and graded by turning angle. Together, these results provide a clear example of how a specific motor pattern can be transformed into different behavioral events by the graded activation of a small set of SPNs. PMID:23910662

Huang, Kuo-Hua; Ahrens, Misha B.; Dunn, Timothy W.; Engert, Florian

2013-01-01

245

Can erosion control structures in large dryland arroyo channels lead to resilient riparian and cienega restoration? Observations from LiDAR, monitoring and modeling at Rancho San Bernardino, Sonora, MX  

NASA Astrophysics Data System (ADS)

The use of erosion control structures to mitigate or even reverse erosion and to restore ecological function along dryland channels (arroyos and gullies) has led to a long list of both successful and failed restoration efforts. We propose that successful implementation of "engineering" approaches to fluvial restoration that include in-channel control structures require either a quantitative approach to design (by scientists and engineers), or intimate on-the-ground knowledge, local observation, and a commitment to adapt and maintain restoration efforts in response to landscape change (by local land managers), or both. We further propose that the biophysical interactions among engineering, sedimentation, flood hydrology and vegetation reestablishment are what determine resilience to destructive extreme events that commonly cause erosion control structure failure. Our insights come from comprehensive monitoring of a remarkable experiment underway at Ranch San Bernardino, Sonora, MX. At this site, private landowners are working to restore ecosystem function to riparian corridors and former cieñega wetlands using cessation of grazing; vegetation planting; upland grass restoration; large scale rock gabions (up to 100 m wide) to encourage local sediment deposition and water storage; and large earthen berms (up to 900 m wide) with cement spillways that form reservoirs that fill rapidly with water and sediment. Well-planned and managed erosion control structures have been used elsewhere successfully in smaller gully networks, but we are unaware of a comparable attempt to use gabions and berms for the sole purpose of ecological restoration along >10 km of arroyo channels draining watersheds on the order of ~400 km2 and larger. We present an approach to monitoring the efficacy of arroyo channel restoration using terrestrial and airborne LiDAR, remote sensing, streamflow monitoring, shallow groundwater monitoring, hydrological modeling and field observation. Our methods allow us to directly quantify the magnitude of sedimentation (and hence reversal of arroyo cutting) upstream of in-channel structures as a function of hydrology, and to quantify the dampening of flood energy caused by erosion control structures and by the restoration of riparian vegetation. We are also able to create a surface water budget that constrains water storage and infiltration by monitoring streamflow at several places above, within, and downstream of restoration efforts. We also speculate on the resilience of such efforts. Quantifying the effects of the restoration efforts at Rancho San Bernardino may prove useful in guiding similar large-scale ecological restoration efforts elsewhere in degraded dryland landscapes.

DeLong, S.; Henderson, W. M.

2012-12-01

246

Continuous Controls: Lighting Energy Management for Retrofit and New Construction Projects  

E-print Network

of continuous control equipment for retrofit and new construction projects. Particular attention is drawn to the need for specifiers and end-users to become more control conscious as continuous controls become more fully integrated into building design....

Schuett, R.

1985-01-01

247

A comparison of enamel erosion by a new sports drink compared to two proprietary products: a controlled, crossover study in situ  

Microsoft Academic Search

Objective. The aim of the study was to measure the erosive potential of a prototype sports drink on enamel in a model in situ.Methods. The study was a single centre, single blind, randomised crossover design balanced for residual effects involving 18 subjects. The drinks were the prototype formulation containing calcium and maltodextrin (test), two sports drink products containing sugars (drink

S Hooper; N. X West; N Sharif; S Smith; M North; J De'Ath; D. M Parker; A Roedig-Penman; M Addy

2004-01-01

248

Gastroesophageal Reflux is Not Associated with Dental Erosion in Children  

PubMed Central

Background & Aims Dental erosion is a complication of gastroesophageal reflux (GER) in adults; in children, it is not clear if GER has a role in dental pathologic conditions. Dietary intake, oral hygiene, high bacterial load, and decreased salivary flow might contribute independently to GER development or dental erosion, but their potential involvement in dental erosion from GER is not understood. We investigated the prevalence of dental erosion among children with and without GER symptoms, and whether salivary flow rate or bacterial load contribute to location-specific dental erosion. Methods We performed a cross-sectional study of 59 children (ages 9–17 y) with symptoms of GER and 20 asymptomatic children (controls); all completed a questionnaire on dietary exposure. Permanent teeth were examined for erosion into dentin, erosion locations, and affected surfaces. The dentist was not aware of GER status, nor was the gastroenterologist aware of dental status. Stimulated salivary flow was measured and salivary bacterial load was calculated for total bacteria, Streptococcus mutans and Lactobacilli. Results Controlling for age, dietary intake, and oral hygiene, there was no association between GER symptoms and dental erosion, by tooth location or affected surface. Salivary flow did not correlate with GER symptoms or erosion. Erosion location and surface were independent of total bacteria and levels of Streptococcus mutans and Lactobacilli. Conclusions Location-specific dental erosion is not associated with GER, salivary flow, or bacterial load. Prospective studies are required to determine the pathogenesis of GER-associated dental erosion and the relationship between dental caries to GER and dental erosion. PMID:21820389

Wild, Yvette K.; Heyman, Melvin B.; Vittinghoff, Eric; Dalal, Deepal H.; Wojcicki, Janet M.; Clark, Ann L.; Rechmann, Beate; Rechmann, Peter

2011-01-01

249

Dating and quantification of erosion processes based on exposed roots  

NASA Astrophysics Data System (ADS)

Soil erosion is a key driver of land degradation and heavily affects sustainable land management in various environments worldwide. An appropriate quantification of rates of soil erosion and a localization of hotspots are therefore critical, as sediment loss has been demonstrated to have drastic consequences on soil productivity and fertility. A consistent body of evidence also exists for a causal linkage between global changes and the temporal frequency and magnitude of erosion, and thus calls for an improved understanding of dynamics and rates of soil erosion for an appropriate management of landscapes and for the planning of preventive or countermeasures. Conventional measurement techniques to infer erosion rates are limited in their temporal resolution or extent. Long-term erosion rates in larger basins have been analyzed with cosmogenic nuclides, but with lower spatial and limited temporal resolutions, thus limiting the possibility to infer micro-geomorphic and climatic controls on the timing, amount and localization of erosion. If based on exposed tree roots, rates of erosion can be inferred with up to seasonal resolution, over decades to centuries of the past and for larger surfaces with homogenous hydrological response units. Root-based erosion rates, thus, constitute a valuable alternative to empirical or physically-based approaches, especially in ungauged basins, but will be controlled by individual or a few extreme events, so that average annual rates of erosion might be highly skewed. In this contribution, we review the contribution made by this biomarker to the understanding of erosion processes and related landform evolution. We report on recent progress in root-based erosion research, illustrate possibilities, caveats and limitations of reconstructed rates, and conclude with a call for further research on various aspects of root-erosion research and for work in new geographic regions.

Stoffel, Markus; Corona, Christophe; Ballesteros-Cánovas, Juan Antonio; Bodoque, José Maria

2013-08-01

250

Assessment of Soil Erosion at a DC Park Facility Spring Valley Park  

E-print Network

1 Assessment of Soil Erosion at a DC Park Facility Spring Valley Park NW Washington, DC Annual of this project is to provide a preliminary site inventory and assessment of soil erosion for the Spring Valley erosion. Due to its location relative to the University and small size it was determined to be an ideal

District of Columbia, University of the

251

Ecological site-based assessments of wind and water erosion: informing accelerated soil erosion management in rangelands  

USGS Publications Warehouse

Accelerated soil erosion occurs when anthropogenic processes modify soil, vegetation or climatic conditions causing erosion rates at a location to exceed their natural variability. Identifying where and when accelerated erosion occurs is a critical first step toward its effective management. Here we explore how erosion assessments structured in the context of ecological sites (a land classification based on soils, landscape setting and ecological potential) and their vegetation states (plant assemblages that may change due to management) can inform systems for reducing accelerated soil erosion in rangelands. We evaluated aeolian horizontal sediment flux and fluvial sediment erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Across the ecological sites, plots in shrub-encroached and shrub-dominated vegetation states were consistently susceptible to aeolian sediment flux and fluvial sediment erosion. Both processes were found to be highly variable for grassland and grass-succulent states across the ecological sites at the plot scale (0.25 Ha). We identify vegetation thresholds that define cover levels below which rapid (exponential) increases in aeolian sediment flux and fluvial sediment erosion occur across the ecological sites and vegetation states. Aeolian sediment flux and fluvial erosion in the study area can be effectively controlled when bare ground cover is 100 cm in length is less than ~35%. Land use and management activities that alter cover levels such that they cross thresholds, and/or drive vegetation state changes, may increase the susceptibility of areas to erosion. Land use impacts that are constrained within the range of natural variability should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds identified here will enable identification of areas susceptible to accelerated soil erosion and the development of practical management solutions.

Webb, Nicholas P.; Herrick, Jeffrey E.; Duniway, Michael C.

2014-01-01

252

Controlled ecological life support system breadboard project, 1988  

NASA Technical Reports Server (NTRS)

The Closed Ecological Life Support System (CELSS) Breadboard Project, NASA's effort to develop the technology required to produce a functioning bioregenerative system, is discussed. The different phases of the project and its current status are described. The relationship between the project components are shown, and major project activities for fiscal years 1989 to 1993 are listed. The Biomass Production Chamber (BPC) became operational and tests of wheat as a single crop are nearing completion.

Knott, W. M.

1990-01-01

253

9 CFR 79.7 - Waiver of requirements for scrapie control pilot projects.  

Code of Federal Regulations, 2012 CFR

...pilot project plan: (1) The determination that an animal is a high-risk animal, if the scrapie control pilot project plan contains testing or other procedures that indicate that an animal, despite meeting the definition of high-risk...

2012-01-01

254

9 CFR 79.7 - Waiver of requirements for scrapie control pilot projects.  

...pilot project plan: (1) The determination that an animal is a high-risk animal, if the scrapie control pilot project plan contains testing or other procedures that indicate that an animal, despite meeting the definition of high-risk...

2014-01-01

255

Effective Monitoring and Control of Outsourced Software Development Projects  

NASA Astrophysics Data System (ADS)

In our study of four outsourcing projects we discover mechanisms to support managerial decision making during software development processes. We report on Customer Office, a framework used in practice that facilitates reasoning about projects by highlighting information paths and making co-ordination issues explicit. The results suggest a key role of modularisation and standardisation to assist in value creation, by facilitating information flow and keeping the overview of the project. The practical implications of our findings are guidelines for managing outsourcing projects such as to have a modularised view of the project based on knowledge domains and to standardise co-ordination operations.

Ponisio, Laura; Vruggink, Peter

256

Particulate erosion mechanisms  

NASA Technical Reports Server (NTRS)

Particulate damage and erosion of ductile metals are today plaguing design and field engineers in diverse fields of engineering and technology. It was found that too many models and theories were proposed leading to much speculation from debris analysis and failure mechanism postulations. Most theories of solid particle erosion are based on material removal models which do not fully represent the actual physical processes of material removal. The various mechanisms proposed thus far are: melting, low-cycle fatigue, extrusion, delamination, shear localization, adhesive material transfer, etc. The experimental data on different materials highlighting the observed failure modes of the deformation and cutting wear processes using optical and scanning electron microscopy are presented. The most important mechanisms proved from the experimental observations of the specimens exposed to both spherical and angular particles are addressed, and the validity of the earlier theories discussed. Both the initial stages of damage and advanced stages of erosion were studied to gain a fundamental understanding of the process.

Veerabhadrarao, P.; Buckley, D. H.

1983-01-01

257

Role of projection in the control of bird flocks.  

PubMed

Swarming is a conspicuous behavioral trait observed in bird flocks, fish shoals, insect swarms, and mammal herds. It is thought to improve collective awareness and offer protection from predators. Many current models involve the hypothesis that information coordinating motion is exchanged among neighbors. We argue that such local interactions alone are insufficient to explain the organization of large flocks of birds and that the mechanism for the exchange of long-range information necessary to control their density remains unknown. We show that large flocks self-organize to the maximum density at which a typical individual still can see out of the flock in many directions. Such flocks are marginally opaque--an external observer also still can see a substantial fraction of sky through the flock. Although this seems intuitive, we show it need not be the case; flocks might easily be highly diffuse or entirely opaque. The emergence of marginal opacity strongly constrains how individuals interact with one another within large swarms. It also provides a mechanism for global interactions: an individual can respond to the projection of the flock that it sees. This provides for faster information transfer and hence rapid flock dynamics, another advantage over local models. From a behavioral perspective, it optimizes the information available to each bird while maintaining the protection of a dense, coherent flock. PMID:25002501

Pearce, Daniel J G; Miller, Adam M; Rowlands, George; Turner, Matthew S

2014-07-22

258

The economics of tobacco control: evidence from the International Tobacco Control (ITC) Policy Evaluation Project.  

PubMed

Over the past few decades, the importance of economic research in advancing tobacco control policies has become increasingly clear. Extensive research has demonstrated that increasing tobacco taxes and prices is the single most cost-effective tobacco control measure. The research contained in this supplement adds to this evidence and provides new insights into how smokers respond to tax and price changes using the rich data on purchase behaviours, brand choices, tax avoidance and evasion, and tobacco use collected systematically and consistently across countries and over time by the International Tobacco Control (ITC) Project. The findings from this research will help inform policymakers, public health professionals, advocates, and others seeking to maximise the public health and economic benefits from higher taxes. PMID:24500268

Tauras, John A; Chaloupka, Frank J; Quah, Anne Chiew Kin; Fong, Geoffrey T

2014-03-01

259

Weathering and Erosion  

NSDL National Science Digital Library

This Classroom Connectors lesson plan discusses weather conditions and their contribution to weathering and erosion. Students learn to explain the process of physical and chemical weathering. They also learn to compare and contrast erosion resulting from wind, ice and water. The site provides goals, objectives, an outline, time required, materials, activities, and closure ideas for the lesson. The Classroom Connectors address content with an activity approach while incorporating themes necessary to raise the activity to a higher cognition level. The major motivation is to employ instructional strategies that bring the students physically and mentally into touch with the science they are studying.

260

Wind Erosion in Tithonium  

NASA Technical Reports Server (NTRS)

30 April 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows wind-eroded sedimentary rocks in Tithonium Chasma, one of the troughs of the Valles Marineris system. The winds responsible for the majority of the erosion blew from the northeast (upper right), creating yardangs (wind erosion ridges) with their tapered ends pointing downwind.

Location near: 4.6oS, 88.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Winter

2005-01-01

261

Mechanisms of shoreline erosion in a back-bay environment, Cape Carancahua, Texas  

E-print Network

Because the back-bays along the coast of Texas are becoming increasingly populated, erosion problems associated with development along this shoreline are becoming more common. Past and present efforts to understand and control shoreline erosion...

Ansari, Ramin

2012-06-07

262

Erosion-corrosion wear of the elements of NPP pipeline systems  

NASA Astrophysics Data System (ADS)

The results of the operational control of erosion-corrosion wear of NPP pipelines are analyzed. The peculiar features of the erosion-corrosion wear of different elements of pipeline systems are revealed.

Baranenko, V. I.; Yanchenko, Yu. A.

2008-05-01

263

Scale linkage and contingency effects of field-scale and hillslope-scale controls of long-term soil erosion: Anthropogeomorphic sediment flux in agricultural loess watersheds of Southern Germany  

NASA Astrophysics Data System (ADS)

Agricultural landscapes with a millennial-scale history of cultivation are common in many loess areas of central Europe. Over time, patterns of erosion and sedimentation have been continually modified via the variable imposition of anthropogenic discontinuities and linkages on fragmented hillslope sediment cascades, which eventually caused the complicated soilscape pattern. These field records challenge topographically oriented models of hillslope erosion and simple predictions of longer-term change of spatial soilscape by cultivation activities. A thorough understanding how soilscape patterns form in the long-term, however, is essential to develop spatial concepts of the sediment budget, particularly for the spatial modeling of anthropogenic hillslope sediment flux using GIS. In this study I used extensive datasets of anthropogenic soil truncation and burial in a typical undulating loess watershed in southern Germany (10 km 2, Wetterau Basin, N of Frankfurt a.M.). Spatial soilscape properties and historic sediment flux, as caused by cultivation over seven millennia, were evaluated by these data. The soilscape pattern on the low-gradient hillslopes of the study area was found to be marked by a statistical near-random pattern of varying depth (thickness) of truncation and overthickened burial. Moreover, it was shown that truncation and burial had developed independently from each other and did not correlate with either hillslope gradient or downslope curvature. Hence, in the field any combination of (few) nearly preserved, severely truncated or completely removed soil profiles with either no, some or a thick sediment cover is present, thereby lacking an obvious spatial pattern. Here, I suggest putting long-term change of the soilscape into a contextual anthropogeomorphic systems perspective, that accommodates components of human-induced soil erosion operating at different spatial scales to interpret the longer-term spatial consequences at the hillslope-system level. In the study area, system scale linkages are marked by the spatial intersection of a finer-scaled managed field system with a broader hillslope-scale framework of 'natural' erosion controls. In the low-gradient study area, field borders exert control over the spatial reference of soil erosion and sedimentation sites. Over time, this brought about a growing historical and spatial contingency change to the soilscape, because of arbitrary spatial changes of the field system which are inherent in its socio-agricultural maintenance. Thus, the very low-gradient and low-erosivity setting of the study area have singled out the agency of human-induced spatial and connectivity controls and contingency for long-term spatial hillslope sediment flux. Although these findings may be less true for different settings, they allow for deriving a generic conceptual model of the linkages between 'natural' and anthropogenic subsystems to interpret the effects of long-term human-induced sediment flux. Accordingly, the resulting balance between on-hillslope net storage and net delivery to streams is scaling with basic physiographic properties of erosivity and sedimentation as well as the degree of anthropogenic hillslope fragmentation. For loess areas in Europe variable fields are fundamental anthropogeomorphic units that determine appropriate system scaling for historic sediment flux analysis and constrain retrodiction and prediction of changing fluxes at a point and a time at watershed scales. Methodical implications address adequate sampling strategies to record soilscape change, as a result of which a critical review of the applicability of the catena concept to long-cultivated hillslopes in central Europe was included. Finally, the suggested refined generic model of long-term, human-controlled sediment flux involves a number of research opportunities, particularly for linking modeling approaches to long-term field records of cultivation-related change in the soilscape.

Houben, Peter

2008-10-01

264

Bioengineering applied to erosion and stability control in the North Apennines (Emilia-Romagna Region, Italy): a check about critical aspects of the works.  

NASA Astrophysics Data System (ADS)

Because of its geological structure, in the Emilia-Romagna Region over 32,000 landslides have been identified. Several works have been made in order to control mass movement's dynamics and to secure of Reno and Lamone Mountain Basin Rivers, the road network and near by villages and towns. Most of the control works dealt with bioengineering practices: palisades piles, geotextiles, seedings, surface flow control works, dikes within main drainage ditches. In order to check about critical aspects related to the use of these techniques in the Apennines, a survey in this basins was designed with specific interest in the several kinds of works realised, in which plant species were mostly used and in the factors that affected the success or failure of the works. Territory encompasses steep slopes covered with woods to low reliefs covered with grasslands. It is characterized by prevailing clays, inducing instability, and arenaceous lithology with impermeable soils; drainage density is quite high and hillsides suffer extensive and severe erosion and slope stability problems. Chestnut woods mainly represent land use at higher altitudes, while coppice, pastures and crops are present on milder hillsides. The remaining part of the basin is covered by vineyards, orchards, ponds and urban areas, which are basically located in the valley floor. Precipitation events mainly consist of rainfall ranging between 950-1015 mm per year; few snowfalls occur during winter and a long dry season lasts from June until September. We have analyzed 187 works designed mainly for the consolidation of slope instabilities through a widespread enhancement of the vegetation cover. The surveyed works are classified as a function of their building features: it can be seen that cribwalls and palisades are by far the most common types, being the 24% and the 34% respectively of the works. As far as the most adopted plant species, they were silver willow (Salix alba), Spanish Broom (Spartium Junceum) and purple willow (Salix purpurea). Only the 25% of the interventions was accomplished by the use of secondary plant species, as tamarisk (Tamarix spp.,) blackthorn (Prunus spinosa) , whitethorn (Crataegus spp.), sea-buckthorn (Hipphopae rhamnoides), wild pear (Pyrus pyraster), cottonwood (Populus nigra), eglantine (Rosa spp.), goat-willow (Salix caprea) and cornel (Cornus sanguinea). Better results were achieved with Spanish Broom, a very rural plant that can effectively colonise even poor soils like badlands; as a matter of fact, more than the 75% of the interventions had positive outcomes The efficacy of the consolidation work by the presence of living structures point out an increase of the stability of those interventions older than 4 years, with taking root species present from 54% to 78%. So far, the construction and the reliability of the works have been monitored, in order to capture critical aspects for the success of works and to build a geo-referenced data base of the existing works and their status.

Selli, Lavinia; Cavazza, Claudio; Pavanelli, Donatella

2013-04-01

265

Grand Tours, Projection Pursuit Guided Tours, and Manual Controls  

Microsoft Academic Search

How do we find structure in multidimensional data when computer screens are only two-dimensional? One approach is to project\\u000a the data onto one or two dimensions. Projections are used in classical statistical methods like principal component analysis\\u000a (PCA) and linear discriminant analysis. PCA (e.g., Johnson and Wichern 2002) chooses a projection to maximize the variance.\\u000a Fisher’s linear discriminant (e.g., Johnson

Dianne Cook; Andreas Buja; Eun-Kyung Lee; Hadley Wickham

266

Climate Change Effects on the Sacramento Basin's Flood Control Projects ANN DENISE FISSEKIS  

E-print Network

Climate Change Effects on the Sacramento Basin's Flood Control Projects By ANN DENISE FISSEKIS B.......................................................................6 Chapter III. Climate Change................................................................11 models...........................................................20 Climate change data

Lund, Jay R.

267

Animating Corrosion and Erosion  

Microsoft Academic Search

In this paper, we present a simple method for animating natural phenomena such as erosion, sedimentation, and acidic corrosion. We discretize the appropriate physical or chemical equations using finite differences, and we use the results to modify the shape of a solid body. We remove mass from an object by treating its surface as a level set and advecting it

Christopher Wojtan; Mark Carlson; Peter J. Mucha; Greg Turk

2007-01-01

268

Erosion of dust aggregates  

E-print Network

Aims: The aim of this work is to gain a deeper insight into how much different aggregate types are affected by erosion. Especially, it is important to study the influence of the velocity of the impacting projectiles. We also want to provide models for dust growth in protoplanetary disks with simple recipes to account for erosion effects. Methods: To study the erosion of dust aggregates we employed a molecular dynamics approach that features a detailed micro-physical model of the interaction of spherical grains. For the first time, the model has been extended by introducing a new visco-elastic damping force which requires a proper calibration. Afterwards, different sample generation methods were used to cover a wide range of aggregate types. Results: The visco-elastic damping force introduced in this work turns out to be crucial to reproduce results obtained from laboratory experiments. After proper calibration, we find that erosion occurs for impact velocities of 5 m/s and above. Though fractal aggregates as ...

Seizinger, Alexander; Kley, Wilhelm

2013-01-01

269

Enhancing liquid jet erosion  

Microsoft Academic Search

Process and apparatus for enhancing the erosive intensity of a high velocity liquid jet when the jet is impacted against a surface for cutting, cleaning, drilling or otherwise acting on the surface. A preferred method comprises the steps of forming a high velocity liquid jet, oscillating the velocity of the jet at a preferred Strouhal number, and impinging the pulsed

Johnson V. E. Jr

1984-01-01

270

External Resource: Weathering and Erosion  

NSDL National Science Digital Library

This activity includes background information about weathering, as well as simple demonstrations/activities to model how weather conditions contribute to weathering and erosion. Topics include: chemical weathering, dunes, erosion, floods, glaciers, physi

1900-01-01

271

External Resource: Erosion and Weathering  

NSDL National Science Digital Library

This is a Teachers' Domain photo essay with images that depict surface features on Earth that result from weathering and erosion, as well as measures designed to mitigate their unwanted effects. Topics: weathering, erosion, sediments, dunes, deltas, glaci

1900-01-01

272

Erosion Rates and Mars Climate  

NASA Astrophysics Data System (ADS)

New erosion rate data during the past 20 Ma from fresh impact craters imaged by the Opportunity rover coupled with long-term erosion rates through time better constrain the link with the long term evolution of climate on Mars.

Golombek, M.; Warner, N.; Ganti, V.; Lamb, M.

2014-07-01

273

78 FR 64909 - Southwestern Region: Invasive Plant Control Project, Carson and Santa Fe National Forests, New...  

Federal Register 2010, 2011, 2012, 2013

...Invasive Plant Control Project, Carson and Santa Fe National Forests, New Mexico AGENCY...controlling invasive plants in the Carson and Santa Fe National Forests. The agency published...gov/land/carson/landmanagement Santa Fe National Forest:...

2013-10-30

274

Successful Pursuit of Small Electrical and Controls Projects by a Small Civil Engineering Firm  

E-print Network

This paper determines how a small, primarily civil engineering firm possessing an electrical and controls group can successfully pursue small electrical and controls projects issued by local electrical generation utilities. Not only...

Gates, Craig

2008-07-25

275

Predicting soil erosion for alternative land uses.  

PubMed

The APEX (Agricultural Policy-Environmental eXtender) model developed in the United States was calibrated for northwestern China's conditions. The model was then used to investigate soil erosion effects associated with alternative land uses at the ZFG (Zi-Fang-Gully) watershed in northwestern China. The results indicated that the APEX model could be calibrated reasonably well (+/-15% errors) to fit those areas with >50% slope within the watershed. Factors being considered during calibration include runoff, RUSLE (Revised Universal Soil Loss Equation) slope length and steepness factor, channel capacity flow rate, floodplain saturated hydraulic conductivity, and RUSLE C factor coefficient. No changes were made in the APEX computer code. Predictions suggest that reforestation is the best practice among the eight alternative land uses (the status quo, all grass, all grain, all grazing, all forest, half tree and half grass, 70% tree and 30% grain, and construction of a reservoir) for control of water runoff and soil erosion. Construction of a reservoir is the most effective strategy for controlling sediment yield although it does nothing to control upland erosion. For every 1 Mg of crop yield, 11 Mg of soil were lost during the 30-yr simulation period, suggesting that expanding land use for food production should not be encouraged on the ZFG watershed. Grass species are less effective than trees in controlling runoff and erosion on steep slopes because trees generally have deeper and more stable root systems. PMID:16455846

Wang, Erda; Xin, Chang; Williams, Jimmy R; Xu, Cheng

2006-01-01

276

Computerized adaptive control weld skate with CCTV weld guidance project  

NASA Technical Reports Server (NTRS)

This report summarizes progress of the automatic computerized weld skate development portion of the Computerized Weld Skate with Closed Circuit Television (CCTV) Arc Guidance Project. The main goal of the project is to develop an automatic welding skate demonstration model equipped with CCTV weld guidance. The three main goals of the overall project are to: (1) develop a demonstration model computerized weld skate system, (2) develop a demonstration model automatic CCTV guidance system, and (3) integrate the two systems into a demonstration model of computerized weld skate with CCTV weld guidance for welding contoured parts.

Wall, W. A.

1976-01-01

277

Vision-based Guidance and Control of Robots in Projective Andreas Ruf, et al  

E-print Network

Vision-based Guidance and Control of Robots in Projective Space Andreas Ruf, et al GRAVIR guiding and controlling a robot in projective three-space using stereo vision. As the proposed method laws fail. 1 Introduction Research in computer vision was very much driven by the robot vision problem

Paris-Sud XI, Université de

278

Rainfall kinetic energy controlling erosion processes and sediment sorting on steep hillslopes: A case study of clay loam soil from the Loess Plateau, China  

NASA Astrophysics Data System (ADS)

Rainfall kinetic energy (KE) can break down aggregates in the soil surface. A better understanding of sediment sorting associated with various KEs is essential for the development and verification of soil erosion models. A clay loam soil was used in the experiments. Six KEs were obtained (76, 90, 105, 160, 270, and 518 J m-2 h-1) by covering wire screens located above the soil surface with different apertures to change the size of raindrops falling on the soil surface, while maintaining the same rainfall intensity (90 ± 3.5 mm h-1). For each rainfall simulation, runoff and sediment were collected at 3-min intervals to investigate the temporal variation of the sediment particle size distribution (PSD). Comparison of the sediment effective PSD (undispersed) and ultimate PSD (dispersed) was used to investigate the detachment and transport mechanisms involved in sediment mobilization. The effective-ultimate ratios of clay-sized particles were less than 1, whereas that of sand-sized particles were greater than 1, suggesting that these particles were transported as aggregates. Under higher KE, the effective-ultimate ratios were much closer to 1, indicating that sediments were more likely transported as primary particles at higher KE owing to an increased severity of aggregate disaggregation for the clay loam soil. The percentage of clay-sized particles and the relative importance of suspension-saltation increased with increasing KE when KE was greater than 105 J m-2 h-1, while decreased with increasing KE when KE was less than 105 J m-2 h-1. A KE of 105 J m-2 h-1 appeared to be a threshold level beyond which the disintegration of aggregates was severe and the influence of KE on erosion processes and sediment sorting may change. Results of this study demonstrate the need for considering KE-influenced sediment transport when predicting erosion.

Wang, L.; Shi, Z. H.; Wang, J.; Fang, N. F.; Wu, G. L.; Zhang, H. Y.

2014-05-01

279

Fuzzy Representation of Soil Erosion  

NASA Astrophysics Data System (ADS)

Fuzzy representation is a productive method to explain the natural processes so that it is near to linguistic form and it is also applicable to estimate the environmental processes in where the uncertainty in information is high. As models proposed to estimate soil erosion also have uncertainties and fuzzy inference system is more flexible in describing the relationship between soil erosion and other factor, especially in managing data and model uncertainties. in the research, it is used simplified model of revised Universal Soil Loss Equation (RUSLE) to estimate soil erosion in dry lands of Kashan area in Central Iran . Then to discover the systematic (IF-Then) rules in soil erosion process, we used inductive reasoning method to discover rules of the causing agents of erosion such as rainfall erosivity, topography factors, soil erodibility , then highly supported rules converted to fuzzy rules. It is resulted that the application of fuzzy inference system for erosion evaluation is applicable in regional level.

Komaki, Ch. B.; Kainz, W.; Alavi Panah, S. K.; Matinfar, H. R.

2009-04-01

280

Cause of Erosion Mitigation  

E-print Network

for predicting erosion · USLE: Universal Soil Loss Equation ­ Most common (not necessarily the best) method://www.techtransfer.osmre.gov/nttmainsite/Library/hbmanual/rusle/fro ntmatter.pdf · 11,000 plot years of data, 47 locations 24 states (1930s-1950s) · 1965 completed USLE · RUSLE (revised) (~1998) · RUSLE2 (revised revised) (~2003) #12;01-5 (R)USLE explained · Empirical

Boisvert, Jeff

281

Toothpaste and erosion.  

PubMed

Dental erosion develops from the chronic exposure to non-bacterial acids resulting in bulk mineral loss with a partly demineralised surface of reduced micro-hardness. Clinical features are loss of surface structures with shallow lesions on smooth surfaces and cupping and flattening of cusps; already in early stages, coronal dentine often is exposed. Not only enamel, but also dentine is therefore an important target tissue for anti-erosion strategies. The main goal of active ingredients against erosion is to increase the acid resistance of tooth surfaces or pellicles. The challenge with toothpastes is that abrasives, otherwise beneficial in terms of cleaning properties, may counteract the effects of active ingredients. Fluoride toothpastes offer a degree of protection, but in order to design more effective formulations, active ingredients in addition to, or other than, fluorides have been suggested. Polyvalent metal cations, Ca/P salts in nano-form, phosphates, proteins, and various biopolymers, e.g. chitosan, are substances under study. The complex combined action of active ingredients and abrasives on the dental hard tissues, and the role of excipients of complex toothpaste formulations are not yet fully understood. Current evidence is flawed by the diversity of experimental designs, and there is no knowledge from clinical studies with patients so far. However, research results indicate that there is potential to develop effective toothpastes in this field. As the prevalence of initial erosive lesions particularly in younger age groups is high in some countries, such strategies would be of great importance for maintaining oral health. PMID:23817062

Ganss, Carolina; Schulze, Katja; Schlueter, Nadine

2013-01-01

282

MULTI-TEMPORAL SOIL EROSION RISK ASSESSMENT IN N. CHALKIDIKI USING A MODIFIED USLE RASTER MODEL  

Microsoft Academic Search

The aim of this work was to test a modified version of the Universal Soil Loss Equation (USLE) for assessing the risks of erosion in N. Chalkidiki, Greece. USLE estimates the severity of erosion, thus assisting the decision process in selecting erosion control measures. Although USLE has several limitations, it was selected because it is the simplest approach while remaining

Ioannis Z. Gitas; Kostas Douros; Chara Minakou; George N. Silleos; Christos G. Karydas

2009-01-01

283

Negligible Soil Erosion After Wildfire Disturbance: Role of the Duff Layer  

Microsoft Academic Search

Wildfires are generally thought to result in increased soil erosion in the immediate post-disturbance years, but many unanswered questions remain regarding the controls of erosional response in different regional settings. Post-fire soil erosion is most often studied and reported in regions where noteworthy erosion occurs. In many of these studies, it may be the case that the duff layer has

Yvonne Martin; Edward Johnson; Joan Gallaway

2010-01-01

284

A study on the erosion of Niigata Beach from ERTS-A imagery  

NASA Technical Reports Server (NTRS)

Coastal erosion of Niigata Beach, Japan as a result of construction works is discussed. The application of ERTS-1 imagery for defining and monitoring the extent of the erosion is described. The contribution of ERTS-1 data to studies leading to effective erosion control methods are reported.

Maruyasu, T.

1973-01-01

285

Analysis/control of in-bed tube erosion phenomena in the Fluidized Bed Combustion (FBC) System. Technical progress report No. 5  

SciTech Connect

This technical report summarizes the research work performed and progress achieved during the period of October 1, 1993 to December 31, 1993. Measurement of particle-tube collision frequency was conducted by an electrostatic impact probe in the bench-scale FBC model. Two series of tests were conducted, in one test the probe traversed vertically along the bed axis. The other test conducted that the probe traversed from the center position to the quarter point of bed diagonal and the wall region. The specific weight loss at different tube circumferential was examined to understand the effect of superficial fluidizing velocity. The bottom section of the test tube was found to be more serious erosion than that of the top section. In order to study the effect of tube orientations on in-bed tube erosion, the sample tubes along with four different angles were used. The sample tubes were also placed horizontally and vertically at the center, and vertically near the wall to quantify the effect of the tube location.

Lee, S.W.

1994-01-01

286

Reduction of erosion in elbows due to flow modifications, phase 1  

NASA Astrophysics Data System (ADS)

The concept of flow-field modification as a method for reducing erosion in bends (elbows) used in pneumatic transport systems is investigated. Flow field modifications were primarily accomplished by injecting air at selected locations within the bends. Part 1 of this project shows the feasibility of the concept. Part 2 of this project will include further experiments and analysis, leading to a design methodology for incorporating this concept into piping systems. This is the final report for Part 1 of this project. It contains a survey of the literature dealing with the erosion in bends (elbows) and the fundamental subjects of erosion and two-phase, gas-solids, flow. Based on this literature survey, a pneumatic transport test loop was constructed. Several bend designs were tested, using sand under a variety of operating conditions. The results of this exploratory effort indicate that modifying the flow field in a bend with jets may: (1) decrease erosion; (2) change the erosion pattern with the same amount of erosion; or (3) significantly increase the erosion process. Data indicate that the erosion rate may be reduced by low-velocity jets for high phase-density flow. Apparently, the interjection of jets with dilute phase-density flow tends to accelerate the erosion process. It is recommended that the project be continued in order to more fully understand the process and its capabilities to solve the difficult technical problem of erosion in bends (elbows).

Johnson, E. K.; Means, K. H.; Eyler, R. L.; Holtzworth, J. D.

1987-11-01

287

PRELIMINARY IMPLEMENTATIONS FOR THE NEW SPIRAL2 PROJECT CONTROL SYSTEM  

E-print Network

schematic layout. The RIB Facility The RIB production process will be achieved through target ion. Olivetto (CNRS-IPHC / Strasbourg, France) Abstract The Spiral2 project consists of a new facility area or to the existing Ganil facility. From October this year, one ion source coupled with a first

Boyer, Edmond

288

15-441: Computer Networks -Project 3 Congestion Control  

E-print Network

, you will implement a BitTorrent-like file transfer application. The application will run on top of UDP website. Date Description March 31 Assignment handed out. PLEASE START EARLY! April 2 Recitation: Project checkpoint is worth 10 points. #12;Original File Chunks ) ".torrent" = Hash( Figure 1: Diagram of bittorrent

Goldstein, Seth Copen

289

PRELIMINARY IMPLEMENTATIONS FOR THE NEW SPIRAL2 PROJECT CONTROL SYSTEM  

Microsoft Academic Search

The Spiral2 project consists of a new facility to provide high intensity rare ions beams. It is based on a primary beam driver accelerator (RFQ followed by a superconducting linac) and a rare ion production process delivering the beam either to a low energy experimental area or to the existing Ganil facility. From October this year, one ion source coupled

P. Gillette; C. Haquin; E. Lécorché; D. Touchard; J. F. Denis; F. Gougnaud; J. F. Gournay; Y. Lussignol; P. Mattei; J. Hosselet; C. Maazouzi; C. Olivetto

290

Critical issues in process control system security : DHS spares project.  

SciTech Connect

The goals of this event are: (1) Discuss the next-generation issues and emerging risks in cyber security for control systems; (2) Review and discuss common control system architectures; (3) Discuss the role of policy, standards, and supply chain issues; (4) Interact to determine the most pertinent risks and most critical areas of the architecture; and (5) Merge feedback from Control System Managers, Engineers, IT, and Auditors.

Hernandez, Jacquelynne; McIntyre, Annie; Henrie, Morgan

2010-10-01

291

Perception of a schistosomiasis control project in rural Kenya by the beneficiaries.  

PubMed

A schistosomiasis control project was implemented in Mwea Rice Irrigation Scheme in Central Kenya between late 1983 and December 1988 by Kenya Medical Research Institute scientists in collaboration with the National Irrigation Board. The aim of the project was to control schistosomiasis through provision of alternative water sources, bath and laundry units, latrines, chemotherapy and health education. The community participated fully. Five years later in December 1988, 203 household heads were interviewed on their perception of the control project in terms of purpose, project ownership and management, benefits, continuity and their knowledge of schistosomiasis transmission cycle. 61% of the respondents were females and 39% males. 92% of them said that the purpose for the project was to treat, control and prevent bilharzia from spreading, and to promote good health. Slightly over 50% said that the project belonged to them but that they would have liked to be more involved in its management. 74% said that they are able to save time because the facilities are now nearer to them; whilst 79% felt that they were saving money because they did not have to buy drugs since they felt healthier. 99% said that they thought that bilharzia has been controlled, and 82% said that their children looked healthier. 95% said that they could see the project surviving for a long time period suggesting that it was self sustaining and they were willing to start a maintenance of facilities fund. Overall, the community appreciated the social, economic and health benefits derived from the control project. PMID:8187654

Katsivo, M N; Muthami, L N; Karama, M; Kingori, F

1993-10-01

292

A Study of Cavitation Erosion  

SciTech Connect

The authors performed experimental study for the purpose of the following two items from a viewpoint of cavitation erosion of a cylindrical orifice in view of a problem at the letdown orifice in PWR (Pressurized Water Reactor). 1. To get the critical cavitation parameter of the cylindrical orifice to establish the design criteria for prevention of cavitation erosion, and 2. to ascertain the erosion rate in such an eventuality that the cavitation erosion occurs with the orifice made of stainless steel with precipitation hardening (17-4-Cu hardening type stainless steel), so that we confirm the appropriateness of the design criteria. Regarding the 1. item, we carried out the cavitation tests to get the critical cavitation parameters inside and downstream of the orifice. The test results showed that the cavitation parameter at inception is independent of the length or the diameter of the orifice. Moreover, the design criteria of cavitation erosion of cylindrical orifices have been established. Regarding the 2. item, we tested the erosion rate under high-pressure conditions. The cavitation erosion actually occurred in the cylindrical orifice at the tests that was strongly resemble to the erosion occurred at the plant. It will be seldom to reproduce resemble cavitation erosion in a cylindrical orifice with the hard material used at plants. We could establish the criteria for preventing the cavitation erosion from the test results. (authors)

Hiromu Isaka [Kansai Electric Power Company (Japan); Masatsugu Tsutsumi; Tadashi Shiraishi [Mitsubishi Heavy Industries Ltd. (Japan); Hiroyuki Kobayashi [Japan Atomic Power Company (Japan)

2002-07-01

293

Palo Verde nuclear generating station feedwater control system optimization project  

Microsoft Academic Search

The Pale Verde nuclear generating station (PVNGS) units were originally supplied with central digital feedwater control systems. Arizona Public Service (APS) implemented a program to improve the performance of the system. Recently, the recommended setting changes were implemented in PVNGS Unit 3. The evaluation of the new feedwater control system settings during a 0 to 100% power ascension with 5%

G. Anderson; G. Singh; C. Nielsen

1991-01-01

294

Statistics of rocky coast erosion and percolation theory  

NASA Astrophysics Data System (ADS)

The dynamics of rocky coasts is an erratic phenomenon featuring numerous small erosion events, but sometimes large dramatic collapses. In this sense, its study should not limit or rely on average erosion rates. Recent studies, based on historical as well as recent data, have indicated that the frequency of magnitude of erosion events display long tail distribution, similar to what observed in landslide. In other words the time evolution of a coast morphology does not enter the classical category of Gaussian process, but rather that of critical systems in physics. We recently proposed a minimal dynamical model of rocky coast erosion which is able to reproduce the diversity of rocky coast morphologies and their dynamics. This model is based on a single, simple ingredient, the retroaction of the coast morphology on the erosive power of the sea. It follows from the idea that erosion can spontaneously create irregular seashores, but, in turn, the geometrical irregularity of the coast participates to the damping of sea-waves, decreasing the average wave amplitude and erosive power. The resulting mutual self-stabilization dynamics of the sea erosion power and coastal irregular morphology leads spontaneously the system to a critical dynamics. Our results indicate then that rocky coast erosion and the statistical theory of percolation are closely related. In this framework, the sometimes fractal geometry of coastlines can be recovered and understood in terms of fractal dimension of the external perimeter of a percolation cluster. From a more practical point of view, the analogy with percolation interfaces means that the coast constitutes a strong, but possibly fragile, barrier to sea erosion, emerging from a self-organised selection process. Accordingly, the effect of a slow weathering degradation of the rocks mechanical properties, as well as other perturbations from natural or human cause, can trigger random and large erosion events difficult to predict and control. To the extent that these ideas apply, natural coasts should be "preserved" and managed with care.

Baldassarri, A.; Sapoval, B.

2012-04-01

295

Integrated Resilient Aircraft Control Project Full Scale Flight Validation  

NASA Technical Reports Server (NTRS)

Objective: Provide validation of adaptive control law concepts through full scale flight evaluation. Technical Approach: a) Engage failure mode - destabilizing or frozen surface. b) Perform formation flight and air-to-air tracking tasks. Evaluate adaptive algorithm: a) Stability metrics. b) Model following metrics. Full scale flight testing provides an ability to validate different adaptive flight control approaches. Full scale flight testing adds credence to NASA's research efforts. A sustained research effort is required to remove the road blocks and provide adaptive control as a viable design solution for increased aircraft resilience.

Bosworth, John T.

2009-01-01

296

Reprint of: Assessment of the use of sediment fences for control of erosion and sediment phosphorus loss after potato harvesting on sloping land.  

PubMed

In humid temperate areas, after harvest of potatoes, it is difficult to prevent soil erosion and diffuse pollution. In some autumn weather conditions, in-field mitigation such as cultivation or sowing are not possible, while edge of field measures can be costly and inflexible. We have assessed the potential of modified sediment fences, widely used on building sites, for erosion mitigation post-harvest of potato crops. Field scale assessments were conducted on fields in the Lunan catchment, eastern Scotland. Sediment retention was estimated by two methods: a topographic survey method using a hand held Real Time Kinematic Global Positioning System (RTK-GPS), and direct measurement of sediment depth using a graduated cane. In the 2010/11 trial the main fence comprised 70 m of entrenched fine mesh (0.25 mm) and coarser mesh (4mm) fabric pinned to a contour fence near the base of the field. This retained an estimated 50.9 m(3) (80.2 tonnes) of sediment, with weighted mean total P (TP) content of 0.09 % in the<2mm soil fraction. In the 2011/12 trial, the main 146 m fence was of intermediate mesh size (1.2mm). The fence was partitioned into nine upslope plots, with 3 replicates of each of 3 cultivation methods: T1 (full grubbing--a light, tined cultivator), T2 (partial grubbing) and T3 (no grubbing). Average plot slopes ranged from 9.9 to 11.0 %. The amounts of TP accumulating as sediment at the fences were: 9.3 (sd=7.8), 11.8 (sd=10.2) and 25.7 (sd=5.8)kg P/ha of upslope plot for the T1, T2 and T3 treatments respectively. PMID:24200093

Vinten, A J A; Loades, K; Addy, S; Richards, S; Stutter, M; Cook, Y; Watson, H; Taylor, C; Abel, C; Baggaley, N; Ritchie, R; Jeffrey, W

2014-01-15

297

Assessment of the use of sediment fences for control of erosion and sediment phosphorus loss after potato harvesting on sloping land.  

PubMed

In humid temperate areas, after harvest of potatoes, it is difficult to prevent soil erosion and diffuse pollution. In some autumn weather conditions, in-field mitigation such as cultivation or sowing are not possible, while edge of field measures can be costly and inflexible. We have assessed the potential of modified sediment fences, widely used on building sites, for erosion mitigation post-harvest of potato crops. Field scale assessments were conducted on fields in the Lunan catchment, eastern Scotland. Sediment retention was estimated by two methods: a topographic survey method using a hand held Real Time Kinematic Global Positioning System (RTK-GPS), and direct measurement of sediment depth using a graduated cane. In the 2010/11 trial the main fence comprised 70 m of entrenched fine mesh (0.25 mm) and coarser mesh (4mm) fabric pinned to a contour fence near the base of the field. This retained an estimated 50.9 m(3) (80.2 tonnes) of sediment, with weighted mean total P (TP) content of 0.09 % in the<2mm soil fraction. In the 2011/12 trial, the main 146 m fence was of intermediate mesh size (1.2mm). The fence was partitioned into nine upslope plots, with 3 replicates of each of 3 cultivation methods: T1 (full grubbing--a light, tined cultivator), T2 (partial grubbing) and T3 (no grubbing). Average plot slopes ranged from 9.9 to 11.0 %. The amounts of TP accumulating as sediment at the fences were: 9.3 (sd = 7.8), 11.8 (sd = 10.2) and 25.7 (sd = 5.8)kg P/ha of upslope plot for the T1, T2 and T3 treatments respectively. PMID:24012897

Vinten, A J A; Loades, K; Addy, S; Richards, S; Stutter, M; Cook, Y; Watson, H; Taylor, C; Abel, C; Baggaley, N; Ritchie, R; Jeffrey, W

2014-01-15

298

Attitude and articulation control solutions for Project Galileo  

NASA Technical Reports Server (NTRS)

Design problems and the solutions adopted for them in the attitude and articulation control subsystem for the Galileo spacecraft are discussed as an illustration of the application of dual-spin control to an interplanetary spacecraft. Following a review of the baseline design of the Galileo system and mission, consideration is given to problems encountered in the areas of autonomous attitude determination, attitude control, spacecraft dynamics and software margins. Design issues raised by subsequent changes in spacecraft configuration are also indicated. It is pointed out that although difficulties associated with control system complexity in a dual-spin interplanetary spacecraft have been satisfactorily resolved for the Galileo mission, the future application of dual spin in interplanetary flight is in doubt.

Rasmussen, R. D.; Brown, T. K.

1980-01-01

299

South Polar Erosion  

NASA Technical Reports Server (NTRS)

24 June 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the results of erosion acting upon a layer of material in the south polar region of Mars. The elliptical pit in the lower left corner of the image was once buried beneath this eroding layer, as well. The processes that eroded the material, and the composition of the material, are unknown. The image is located near 80.7oS, 300.9oW, and covers an area about 3 km (1.9 mi) wide. Sunlight illuminates this scene from the top.

2004-01-01

300

Wind Erosion in Aeolis  

NASA Technical Reports Server (NTRS)

09 August 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the effects of severe wind erosion of layered sedimentary rock in the Aeolis region of Mars. The sharp ridges formed by wind movement from the lower left (southwest) toward top/upper right (northeast) are known as yardangs. The dark patches in the lower half of the image are sand dunes. This scene is located near 5.0oS, 203.7oW, and covers an area about 3 km (1.9 mi) across. Sunlight illuminates the terrain from the left/upper left.

2004-01-01

301

Control System for Designed Mobile Robot – Project, Implementation, and Tests  

Microsoft Academic Search

Thanks to highly sophisticated control techniques, modern mobile robots are capable of accomplishing advanced tasks. Briefly,\\u000a mobile robots can be dived into two main branches: research devices and consumer devices. The firs class usually consists\\u000a of prototypes used for testing and verification of various control algorithms. The latter is represented by efficient, dependable\\u000a and fulfilling industrial safety requirements robotic vehicles,

Stanis?aw Koz?owski; Jaros?aw Majchrzak

302

2230 IEEE TRANSACTIONS ON AUTOMATIC CONTROL, VOL. 58, NO. 9, SEPTEMBER 2013 Optimal Control on Lie Groups: The Projection  

E-print Network

2230 IEEE TRANSACTIONS ON AUTOMATIC CONTROL, VOL. 58, NO. 9, SEPTEMBER 2013 Optimal Control on Lie--Many nonlinear systems of practical interest evolve on Lie groups or on manifolds acted upon by Lie groups. Ex on (noncompact) Lie groups. This algorithm generalizes the projection operator approach for trajectory

Instituto de Sistemas e Robotica

303

Piping flow erosion in water retaining structures: inferring erosion rates from hole erosion tests and quantifying the failure time  

E-print Network

Piping flow erosion in water retaining structures: inferring erosion rates from hole erosion tests-en-Provence Cedex 5, France E-mail: stephane.bonelli@cemagref.fr Abstract The piping flow erosion process, involving structures. Such a pipe can be imputed to roots or burrows. The coefficient of erosion must be known in order

Paris-Sud XI, Université de

304

Erosion from a complex watershed  

E-print Network

. Effects of rill erosion within the erosion process we~-e also studied in this research. A 1. 52 x 1. 52-meter plot was established in a laboratory, and a rainulator was used to simulate rainfall. The plot was established with a 9 percent slope.... Effects of rill erosion within the erosion process we~-e also studied in this research. A 1. 52 x 1. 52-meter plot was established in a laboratory, and a rainulator was used to simulate rainfall. The plot was established with a 9 percent slope...

Kuh, Hsien-chien

2012-06-07

305

Coastal erosion and accretion rates in Greece  

NASA Astrophysics Data System (ADS)

Erosion threatens many coastal regions of Greece. Anthropogenic changes of landforms such as coastal roads built on even narrow beaches, sand mining for construction, poor design of coastal structures that interfere with sediment, and dams without sediment bypasses have significantly reduced beach widths. We present erosion rates for different beaches, some of which are in sensitive ecosystems, otherwise "protected" by local and EU ordinances. By comparing inferences of beach widths in varying intervals from 1933 to 2006, we infer that the construction of dams in Acheloos river in western Greece, built in a faraonic attempt to partially divert its flows to eastern Greece, this is responsible for up to 20m/year erosion rates observed in certain locales in the Acheloos delta. More characteristic erosion rates in the region are ~ 2m/year. By contrast, there appears rapid accretion of up to 4m/year in the beaches around the Nestos delta in northern Greece (Papadopoulos, 2009). In beaches that are not near large river deltas, erosion rates range from 0.5m/year to 1m/year. While we have not done comprehensive comparisons among coastlines with different levels of coastal development, it does appear that rapid coastal development correlates well with erosion rates. The underlying problem is the complete lack of any semblance of coastal zone management in Greece and substandard design of coastal structures, which are often sited without any measurements of waves and currents offshore (Synolakis et al, 2008). Beach maintenance remains an exotic concept for most local authorities, who invariably prefer to build hard coastal structures to "protect" versus nourish, siting lack of experience with nourishment and "environmental" concerns. In certain cases, choices are dictated by costs, the larger the cost the easier the project gets approved by regulatory authorities, hence the preference for concrete or rubble structures. We conclude that, unless urgent salvage measures are initiated to protect the coastal zone and educate government and local authorities on sustainable management, several beaches will disappear within the next two decades. References Papadopoulos, C., 2009, Comperative assessment of coastal erosion in the regions of north Amvrakikos gulf, Acheloos delta, Nestos delta, Kos, Limnos, and Kitros, Diploma Thesis, Technical Univerity of Crete, Chanea, Greece, 130 p.( In greek). Synolakis, C.E., Kalligeris, N., Foteinis, S., Voukouvalas, E., 2008, The Plight of the Beaches of Crete, Solutions to Coastal Disasters 2008, Conference Proceedings ASCE, pp. 495-506, (doi 10.1061/40968(312)45)

Foteinis, Spyros; Papadopoulos, Costas; Koutsogiannaki, Irini; Synolakis, Costas

2010-05-01

306

Soil erosion after forest fires in the Valencia region  

NASA Astrophysics Data System (ADS)

Soil erosion after forest fire is triggered by the lack of vegetation cover and the degradation of the physical, biological and chemical properties (Martí et al., 2012; Fernández et al., 2012; Guénon, 2013). Valencia region belongs to the west Mediterranean basin ("Csa", Köppen climate classification), with drought summer periods that enhance forest fire risk. The characteristics of the climate, lithology and land use history makes this region more vulnerable to soil erosion. In this area, fire recurrence is being increased since late 50s (Pausas, 2004) and post-fire erosion studies became more popular from 80's until nowadays (Cerdá and Mataix-Solera, 2009). Research in Valencia region has contributed significantly to a better understanding of the effect of spatial and temporal scale on runoff and sediment yield measurements. The main achievements concerns: a) direct measurement of erosion rates under a wide range of methodologies (natural vs simulated rainfall, open vs closed plots); from micro- to meso-plot and catchment scale in single (Rubio et al., 1994; Cerdà et al., 1995; Cerdà 1998a; 1998b; Llovet et al., 1998; Cerdà, 2001; Calvo-Cases et al., 2003; Andreu et al., 2001; Mayor et al., 2007; Cerdà and Doerr, 2008) and multiples fires (Campo et al., 2006; González-Pelayo et al., 2010a). Changes in soil properties (Sanroque et al., 1985; Rubio et al., 1997; Boix-Fayós, 1997; Gimeno-Garcia et al., 2000; Guerrero et al., 2001; Mataix-Solera et al., 2004; González-Pelayo et al., 2006; Arcenegui et al., 2008; Campo et al., 2008; Bodí et al., 2012), in post-fire vegetation patterns (Gimeno-García et al., 2007) and, studies on mitigation strategies (Bautista et al., 1996; Abad et al., 2000). b) Progress to understanding post-fire erosion mechanism and sediment movement (Boix-Fayós et al., 2005) by definition of thresholds for sediment losses; fire severity, slope angle, bedrock, rain characteristics, vegetation pattern and ecosystem resilience (Mayor et al., 2007; González-Pelayo et al., 2010b). The knowledge achieved on post-fire erosion must very valuable for new insights and new strategies for landscape management. This research will review the State-of-the-Art of the contribution of the research on soil erosion as a consequence of forest fires in the Valencia Region. The review will show the contribution of the pioneers in the 80's when the USLE and mapping was the main too, the use of plots under simulated and natural rainfall, and also the strategies to control the soil erosion. Acknowledgements The research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE FP7 project 603498 supported this research. References Abad, N., Bautista, S., Blade, C., Caturla, R.N. 2000. Seeding and mulching as erosion control techniques after wildfires in the Valencia region. En P. Balabanis, D. Peter, A. Ghazi y M. Tsogas (Eds.), Mediterranean Desertification Research Results and Policy Implications. Directorate-General Research, vol. 2. European Commission, Brussels, 419-429. Andreu, V., Imeson, A.C., Rubio, J.L. 2001. Temporal changes in soil aggregates and water erosion after a wildfire in a Mediterranean pine forest. Catena. 44, 69-84. Arcenegui, V., Mataix-Solera, J., Guerrero, C., Zornoza, R., Mataix-Beneyto, J., García-Orenes, F., 2008. Immediate effects of wildfires on water repellency and aggregate stability in Mediterranean calcareous soils. Catena 74, 219-226. Bautista, S., Bellot, J., Vallejo, R. 1996. Mulching treatment for postfire soil conservation in a semiarid ecosystem. Arid Soil Research and Rehabilitation 10, 235-242. Bodí, M., Mataix-Solera, J., Stefan H. Doerr, S.H., Cerdà, A. 2012. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma 160, 599-607. Boix-Fayos, C. 1997. The roles of texture and structure in the water retention capacity of burnt Mediterranean soils with varying rainfall. Catena 31, 219-236. Boix-Fayos, C., Martínez-Mena, M., Calvo-Cases, A., Castillo, V.M., Albad

González-Pelayo, Óscar; Keizer, Jan Jacob; Cerdà, Artemi

2014-05-01

307

The Monitoring Erosion of Agricultural Land and spatial database of erosion events  

NASA Astrophysics Data System (ADS)

In 2011 originated in The Czech Republic The Monitoring Erosion of Agricultural Land as joint project of State Land Office (SLO) and Research Institute for Soil and Water Conservation (RISWC). The aim of the project is collecting and record keeping information about erosion events on agricultural land and their evaluation. The main idea is a creation of a spatial database that will be source of data and information for evaluation and modeling erosion process, for proposal of preventive measures and measures to reduce negative impacts of erosion events. A subject of monitoring is the manifestations of water erosion, wind erosion and slope deformation in which cause damaged agriculture land. A website, available on http://me.vumop.cz, is used as a tool for keeping and browsing information about monitored events. SLO employees carry out record keeping. RISWC is specialist institute in the Monitoring Erosion of Agricultural Land that performs keeping the spatial database, running the website, managing the record keeping of events, analysis the cause of origins events and statistical evaluations of keeping events and proposed measures. Records are inserted into the database using the user interface of the website which has map server as a component. Website is based on database technology PostgreSQL with superstructure PostGIS and MapServer UMN. Each record is in the database spatial localized by a drawing and it contains description information about character of event (data, situation description etc.) then there are recorded information about land cover and about grown crops. A part of database is photodocumentation which is taken in field reconnaissance which is performed within two days after notify of event. Another part of database are information about precipitations from accessible precipitation gauges. Website allows to do simple spatial analysis as are area calculation, slope calculation, percentage representation of GAEC etc.. Database structure was designed on the base of needs analysis inputs to mathematical models. Mathematical models are used for detailed analysis of chosen erosion events which include soil analysis. Till the end 2012 has had the database 135 events. The content of database still accrues and gives rise to the extensive source of data that is usable for testing mathematical models.

Kapicka, Jiri; Zizala, Daniel

2013-04-01

308

Multicontroller: an object programming approach to introduce advanced control algorithms for the GCS large scale project  

E-print Network

The GCS (Gas Control System) project team at CERN uses a Model Driven Approach with a Framework - UNICOS (UNified Industrial COntrol System) - based on PLC (Programming Language Controller) and SCADA (Supervisory Control And Data Acquisition) technologies. The first' UNICOS versions were able to provide a PID (Proportional Integrative Derivative) controller whereas the Gas Systems required more advanced control strategies. The MultiController is a new UNICOS object which provides the following advanced control algorithms: Smith Predictor, PFC (Predictive Function Control), RST* and GPC (Global Predictive Control). Its design is based on a monolithic entity with a global structure definition which is able to capture the desired set of parameters of any specific control algorithm supported by the object. The SCADA system -- PVSS - supervises the MultiController operation. The PVSS interface provides users with supervision faceplate, in particular it links any MultiController with recipes: the GCS experts are ab...

Cabaret, S; Coppier, H; Rachid, A; Barillère, R; CERN. Geneva. IT Department

2007-01-01

309

Low frequency cavitation erosion  

NASA Astrophysics Data System (ADS)

Damage of diesel engine piston sleeve liners due to cavitation of the coolant fluid can be severe. Coolant fluid additives are used to inhibit cavitation damage, and are evaluated by industry suppliers using ASTM G32-98 Standard Test Method for Cavitation Erosion Using Vibratory Apparatus. The ASTM G32-98 test procedure uses an ultrasonic horn at 20 kHz to vibrate a test button in the coolant. The test button mass loss and surface appearance are studied to sort the performance of new coolant additives. Mismatch between good lab performers and actual engine test runs has raised concerns over the current lab test. The frequency range of the current test has been targeted for investigation. A low frequency, less than 2000 Hz, test rig was built to explore the cavitation damage. The test system did produce cavitation on the surface of the test button for a period of 36 h, with minimal mass loss. The test rig experienced cyclic fatigue when test times were extended. The work is now focusing on designing a better test rig for long duration tests and on developing numerical models in order to explore the effects of cavitation excitation frequency on surface erosion.

Pardue, Sally J.; Chandekar, Gautam

2002-11-01

310

Projective and lag synchronization of a novel hyperchaotic system via impulsive control  

NASA Astrophysics Data System (ADS)

Recently, Yang, Zhang, and Chen (2009) have proposed a novel hyperchaotic system. This paper studies the projective and lag synchronization of this novel hyperchaotic system using an impulsive control technique. Some sufficient conditions of projective and lag synchronization of such new system are derived from strict mathematical theories. Numerical examples are worked through for illustrating the main results.

Chen, Juan; Liu, Hui; Lu, Jun-an; Zhang, Qunjiao

2011-04-01

311

THE SMART CAR PROJECT: A CASE STUDY IN COMPUTER-MEDIATED CONTROL  

E-print Network

significance and application in a wide range of applications ranging from "Smart Highway SystemsTHE SMART CAR PROJECT: A CASE STUDY IN COMPUTER-MEDIATED CONTROL by O. Daniel Gott A project of the Smart Car mobile platform. Beginning with the process of selection of the mechanical platform, we

Krovi, Venkat

312

LIGHTING RESEARCH PROGRAM Project 5.4 DALI Control Standard (NEMA Proposal)  

E-print Network

LIGHTING RESEARCH PROGRAM Project 5.4 DALI Control Standard (NEMA Proposal) FINAL REPORT Prepared individual manufacturer or seller's products or services by virtue of this standard or guide. In publishing

313

INDUSTRIAL POLLUTION CONTROL DIVISION REPORTS AND PROJECT ABSTRACTS  

EPA Science Inventory

This report contains bibliographic information and abstracts for all reports issued by EPA and its predecessor agencies on the development and demonstration of technology to control pollution from those industries which are assigned to IERL-Cincinnati. The major industries includ...

314

Fuzzy discriminant analysis based feature projection in myoelectric control  

Microsoft Academic Search

The myoelectric signal (MES) from human muscles is usually utilized as an input to the controller of a multifunction prosthetic hand. In such a system, a pattern recognition approach is usually employed to discriminate between the MES from different classes. Since the MES is recorded using multi channels, the feature vector size can become very large. In order to reduce

Rami N. Khushaba; Adel Al-Jumaily; Ahmed Al-Ani

2008-01-01

315

[Problems and improvements of water conservancy projects combined with schistosomiasis control in river beaches].  

PubMed

Water conservancy projects combined with schistosomiasis prevention and control are crucial measures to change the habitats of Oncomelania hupensis and are helpful for schistosomiasis control. In this paper, the epidemic characteristics of O. hupensis in lake regions are elaborately analyzed. Also, the specialty problems and applications of the different projects in lake regions are exhaustively discussed. According to the above analysis, some measures and improvements are propounded to deal with these problems. PMID:23012964

Li, Fei; Min, Feng-Yang; Lu, Jin-You; Wang, Jia-Sheng

2012-06-01

316

Physical modeling and monitoring of the process of thermal-erosion of an ice-wedge during a partially-controlled field experiment (Bylot Island, NU, Canada)  

NASA Astrophysics Data System (ADS)

Syngenetic ice-wedges polygons are widespread periglacial features of the Arctic. On Bylot Island, Nunavut, Canada, numerous thermo-erosion gullies up to several 100's m in length developed in polygonal wetlands during the last decades. These gullies contributed to drainage of these wetlands and changed dramatically local ecological conditions. Concentrated and repeated snowmelt surface runoff infiltrated frost cracks, where convective heat transfer between flowing water and ice initiated piping in ice wedges leading to the rapid development of tunnels and gullies in the permafrost (Fortier D. et al., 2007). We conducted field experiments to quantify the convection process and speed of ice wedges ablation. The experiments were accomplished between the 23/06/2013 and the 05/07/2013 over A; an exposed sub-horizontal ice-wedge surface and B; a tunnel in an ice-wedge crack. The ice was instrumented with graduated sticks to calculate the ice ablation following the flow of a defined amount of water. A fixed quantity of water obtained from a nearby waterfall was diverted over the ice through a PVC pipe. Water temperature Wt (K), quantity Wq (L s-1 or m3 s-1), ice ablation rate Iar (m s-1) and convective heat transfer coefficient ? (W m-2 K) were obtained during the 5 experiments. The objective of this paper is to quantify the heat transfer process from field measurements from an ice wedge under ablation and to compare with coefficients from previous researches and in the literature. For each experiment with the ice-surface scenario, water temperature varied between 280 K and 284 K. Discharge varied between 0.0001 and 0.0003 m3 s-1. Ablation rate varied between 1.8 * 10-5 and 0.0004 m s-1. Heat transfer coefficient varied between 706 and 11 655 W m-2 K and between 54 and 4802 W of heat was transferred to ice. For each experiment with the tunnel scenario, water temperature was 284 K × 1 K. Discharge was 0.0002 m3 s-1. Ablation rate varied between 0.0001 and 0.0003 m s-1. Heat transfer coefficient varied between 2644 and 7934 W m-2 K and between 1791 and 5374 W of heat was transferred to ice. Water temperature exiting the tunnel was less than 279 K. Both contexts of experimentation are occurring frequently during gully development. A small input of water over exposed massive-ice can erode significant volume of ice-wedges ice, thermally and mechanically. Empiric determination of the heat transfer coefficient using the parameters measured in the field will provide a better understanding of water temperature and discharge relative importance in the thermo-erosion of ice. Fortier, D., Allard, M., et al. (2007). "Observation of rapid drainage system development by thermal erosion of ice wedges on Bylot island, Canadian Arctic Archipelago." Permafrost and Periglacial Processes 18(3): 229-243.

Godin, E.; Fortier, D.

2013-12-01

317

Control Account Manager (CAM) Responsibilities Control Account Manager (CAM) responsibilities are listed in the PPPL Project  

E-print Network

Control Account Manager (CAM) Responsibilities Control Account Manager (CAM) responsibilities and relationships. · Incorporate control milestones into the schedule · Resource load the schedule · Identify · Indicate completion and required close of control accounts #12;

Princeton Plasma Physics Laboratory

318

Erosion effects on TVC vane heat transfer characteristics  

NASA Astrophysics Data System (ADS)

This work describes the effects of erosion on the heat transfer characteristics on thrust vector control vanes exposed to aluminized propellant exhaust flows. This was accomplished using an inverse heat transfer parameter identification of quarter scale models. The model is based on a four node lumped parameter system with two heat energy inputs. The erosion is modeled as decreasing the geometric dimensions linearly as function of time and percentage of aluminum in the propellant. Excellent agreement was found between experimental and model temperature profiles. The heat transfer coefficients of the vanes were found to decrease with increasing erosion rates.

Gardner, Steven R.

1994-03-01

319

THROUGHFLOW, OVERLAND FLOW AND EROSION  

Microsoft Academic Search

The Horton (1945) infiltration model of surface runoff and erosion is shown to be of much more limited geomorphic application than has been recognised hitherto. It is most applicable to clay badlands with low infiltration capacities and little weathered cover, and is one end-member of a wide spectrum of erosion models. The other end-member applies to slopes with high infiltration

M. J. KIRKBY; R. J. CHORLEY

1967-01-01

320

Lightweight Prevention of Architectural Erosion  

Microsoft Academic Search

Avoiding architectural erosion helps extend the lifetime of an evolving software system. Erosion can be reduced by ensuring that (i) developers share a good understanding of a system's architecture; (ii) alignment is preserved between the architectural description and its implementation at all stages of system construction and maintenance; and (iii) architectural changes are treated with the same care and attention

Ciaran O'reilly; Philip J. Morrow; David W. Bustard

2003-01-01

321

SOIL EROSION AND CONSERVATION: PREDICTION  

E-print Network

SOIL EROSION AND CONSERVATION: PREDICTION AND MANAGEMENT DICK WOLKOWSKI DEPT. OF SOIL SCIENCE UW ABANDONED EROSION SALINIZATION WATER-LOGGING 90% OF US CROPLAND LOSING SOIL FASTER THAN IT IS REPLACED >1 t/a/yr PIMENTEL ET AL., 1995 #12;SIGNIFICANT SOIL LOSS IN THE USA WATER 3.5 X 109 T/yr WIND 1.5 X

Balser, Teri C.

322

Rainfall erosion model  

NASA Astrophysics Data System (ADS)

A model describing rainfall erosion over the course of a long time period is proposed. The model includes: (1) a new equation of detachment of soil particles by water flows based on the Mirtskhulava equation; (2) a new equation for the transport capacity of the flow based on a modified Bagnold equation, which is used in the AGNPS model; (3) modified SCS runoff equation; (4) probability distributions for rainfall. The proposed equations agree satisfactorily with the data of on-site observations of the Moldova and Nizhnedevitsk water-balance stations. The Monte Carlo method is used for numerical modeling of random variables. The results of modeling agree satisfactorily with empirical equations developed for conditions in Russia and the United States. The effect of climatic conditions on the dependence of longtime average annual soil loss on various factors is analyzed. Minimum information is used for assigning the initial data.

Sukhanovskii, Yu. P.

2010-09-01

323

Insular erosion, isostasy, and subsidence.  

PubMed

Organic reefs and shore erosion record the intersection of sea level with islands. From this record it is possible to reconstruct the history of vertical movement of the islands and the adjacent deep sea floor, including midplate swells. As judged by coral thickness, islands with barrier reefs sink as though they were on thermally youthful crust regardless of the actual age. Reefless islands do not sink until truncated by erosion. Apparently, thermal subsidence is balanced by isostatic uplift in response to erosion. Barrier reefs prevent wave erosion of encircled volcanoes and capture products of stream erosion so that isostatic uplift is eliminated. Insular shelves widen initially at rates of 0.6 to 1.7 kilometers per million years; the rates decrease with time. Thus the subsidence of islands depends on the size of the is land and the presence of reefs, and it may not always be the same as that of the surrounding oceanic crust. PMID:17816008

Menard, H W

1983-05-27

324

National Ignition Facility Project Completion and Control System Status  

SciTech Connect

The National Ignition Facility (NIF) is the world's largest and most energetic laser experimental system providing a scientific center to study inertial confinement fusion (ICF) and matter at extreme energy densities and pressures. Completed in 2009, NIF is a stadium-sized facility containing a 1.8-MJ, 500-TW 192-beam ultraviolet laser and target chamber. A cryogenic tritium target system and suite of optical, X-ray and nuclear diagnostics will support experiments in a strategy to achieve fusion ignition starting in 2010. Automatic control of NIF is performed by the large-scale Integrated Computer Control System (ICCS), which is implemented by 2 MSLOC of Java and Ada running on 1300 front-end processors and servers. The ICCS framework uses CORBA distribution for interoperation between heterogeneous languages and computers. Laser setup is guided by a physics model and shots are coordinated by data-driven distributed workflow engines. The NIF information system includes operational tools and a peta-scale repository for provisioning experimental results. This paper discusses results achieved and the effort now underway to conduct full-scale operations and prepare for ignition.

Van Arsdall, P J; Azevedo, S G; Beeler, R G; Bryant, R M; Carey, R W; Demaret, R D; Fisher, J M; Frazier, T M; Lagin, L J; Ludwigsen, A P; Marshall, C D; Mathisen, D G; Reed, R K

2009-10-02

325

Does vegetation prevent wave erosion of salt marsh edges?  

PubMed Central

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves. PMID:19509340

Feagin, R. A.; Lozada-Bernard, S. M.; Ravens, T. M.; Moller, I.; Yeager, K. M.; Baird, A. H.

2009-01-01

326

Does vegetation prevent wave erosion of salt marsh edges?  

PubMed

This study challenges the paradigm that salt marsh plants prevent lateral wave-induced erosion along wetland edges by binding soil with live roots and clarifies the role of vegetation in protecting the coast. In both laboratory flume studies and controlled field experiments, we show that common salt marsh plants do not significantly mitigate the total amount of erosion along a wetland edge. We found that the soil type is the primary variable that influences the lateral erosion rate and although plants do not directly reduce wetland edge erosion, they may do so indirectly via modification of soil parameters. We conclude that coastal vegetation is best-suited to modify and control sedimentary dynamics in response to gradual phenomena like sea-level rise or tidal forces, but is less well-suited to resist punctuated disturbances at the seaward margin of salt marshes, specifically breaking waves. PMID:19509340

Feagin, R A; Lozada-Bernard, S M; Ravens, T M; Möller, I; Yeager, K M; Baird, A H

2009-06-23

327

Using hilltop curvature to derive the spatial distribution of erosion rates  

NASA Astrophysics Data System (ADS)

Erosion rates dictate the morphology of landscapes, and therefore quantifying them is a critical part of many geomorphic studies. Methods to directly measure erosion rates are expensive and time consuming, whereas topographic analysis facilitates prediction of erosion rates rapidly and over large spatial extents. If hillslope sediment flux is nonlinearly dependent on slope then the curvature of hilltops will be linearly proportional to erosion rates. In this contribution we develop new techniques to extract hilltop networks and sample their adjacent hillslopes in order to test the utility of hilltop curvature for estimating erosion rates using high-resolution (1 m) digital elevation data. Published and new cosmogenic radionuclide analyses in the Feather River basin, California, suggest that erosion rates vary by over an order of magnitude (10 to 250 mm kyr-1). Hilltop curvature increases with erosion rates, allowing calibration of the hillslope sediment transport coefficient, which controls the relationship between gradient and sediment flux. Having constraints on sediment transport efficiency allows estimation of erosion rates throughout the landscape by mapping the spatial distribution of hilltop curvature. Additionally, we show that hilltop curvature continues to increase with rising erosion rates after gradient-limited hillslopes have emerged. Hence hilltop curvature can potentially reflect higher erosion rates than can be predicted by hillslope gradient, providing soil production on hilltops can keep pace with erosion. Finally, hilltop curvature can be used to estimate erosion rates in landscapes undergoing a transient adjustment to changing boundary conditions if the response timescale of hillslopes is short relative to channels.

Hurst, Martin D.; Mudd, Simon M.; Walcott, Rachel; Attal, Mikael; Yoo, Kyungsoo

2012-06-01

328

Projection based MIMO control performance monitoring: I—covariance monitoring in state space  

Microsoft Academic Search

In this paper we propose a new control performance monitoring method based on subspace projections. We begin with a state space model of a generally non-square process and derive the minimum variance control (MVC) law and minimum achievable variance in a state feedback form. We derive a multivariate time delay (MTD) matrix for use with our extended state space formulation,

Christopher A. McNabb; S. Joe Qin

2003-01-01

329

Automatic differentiation and spectral projected gradient methods for optimal control problems  

Microsoft Academic Search

Automatic differentiation and nonmonotone spectral projected gradient techniques are used for solving optimal control problems. The original problem is reduced to a nonlinear programming one using general Runge–Kutta integration formulas. Canonical formulas which use a fast automatic differentiation strategy are given to compute derivatives of the objective function. On the basis of this approach, codes for solving optimal control problems

Ernesto G. Birgina; YURI G. EVTUSHENKO

1998-01-01

330

Coastal Change Along the Shore of Northeastern South Carolina: The South Carolina Coastal Erosion Study  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the South Carolina Sea Grant Consortium, conducted a 7-year, multi-disciplinary study of coastal erosion in northeastern South Carolina. The main objective was to understand the geologic and oceanographic processes that control sediment movement along the region's shoreline and thereby improve projections of coastal change. The study used high-resolution remote sensing and sampling techniques to define the geologic framework and assess historic shoreline change. Based on these findings, oceanographic-process studies and numerical modeling were carried out to determine the rates and directions of sediment transport along South Carolina's Grand Strand.

Barnhardt, W. A., (Edited By)

2009-01-01

331

Landfill final covers and soil loss from water erosion  

SciTech Connect

Federal Subtitle D rules require that landfill final covers be designed so as to {open_quotes}minimize erosion{close_quotes} and {open_quotes}be capable of sustaining native plant growth.{close_quotes} The Universal Soil Loss Equation (USLE) has been recommended by the EPA as the most appropriate means for evaluating the suitability of landfill final cover designs with regard to soil loss from water erosion. Since the introduction of the original USLE, two predictive tools have been introduced that are more appropriate for determining soil loss from water erosion. The Revised Universal Soil Loss Equation (RUSLE) model, the intermediate product of erosion research since the development of the original USLE, and the Water Erosion Prediction Program (WEPP) are presented. These models are improved estimating tools that better account for landfill final cover design variables such as slope length, steepness, and non-agricultural cropping and management scenarios than the outdated USLE. The regulatory premise for requiring erosion design and erosion control planning for landfill final cover systems and their practical implementation is also discussed.

Hotchkiss, T.R. [HDR Engineering, Dallas, TX (United States)

1995-12-31

332

Bank Erosion as a Desirable Attribute of Rivers  

NSDL National Science Digital Library

Bank erosion is integral to the functioning of river ecosystems. It is a geomorphic process that promotes riparian vegetation succession and creates dynamic habitats crucial for aquatic and riparian plants and animals. River managers and policymakers, however, generally regard bank erosion as a process to be halted or minimized in order to create landscape and economic stability. Here, we recognize bank erosion as a desirable attribute of rivers. Recent advances in our understanding of bank erosion processes and of associated ecological functions, as well as of the effects and failure of channel bank infrastructure for erosion control, suggest that alternatives to current management approaches are greatly needed. In this article, we develop a conceptual framework for alternatives that address bank erosion issues. The alternatives conserve riparian linkages at appropriate temporal and spatial scales, consider integral relationships between physical bank processes and ecological functions, and avoid secondary and cumulative effects that lead to the progressive channelization of rivers. By linking geomorphologic processes with ecological functions, we address the significance of channel bank erosion in sustainable river and watershed management.

Joan L. Florsheim (University of California at Davis;)

2008-06-01

333

Remote Imaging Applied to Schistosomiasis Control: The Anning River Project  

NASA Technical Reports Server (NTRS)

The use of satellite imaging to remotely detect areas of high risk for transmission of infectious disease is an appealing prospect for large-scale monitoring of these diseases. The detection of large-scale environmental determinants of disease risk, often called landscape epidemiology, has been motivated by several authors (Pavlovsky 1966; Meade et al. 1988). The basic notion is that large-scale factors such as population density, air temperature, hydrological conditions, soil type, and vegetation can determine in a coarse fashion the local conditions contributing to disease vector abundance and human contact with disease agents. These large-scale factors can often be remotely detected by sensors or cameras mounted on satellite or aircraft platforms and can thus be used in a predictive model to mark high risk areas of transmission and to target control or monitoring efforts. A review of satellite technologies for this purpose was recently presented by Washino and Wood (1994) and Hay (1997) and Hay et al. (1997).

Seto, Edmund Y. W.; Maszle, Don R.; Spear, Robert C.; Gong, Peng

1997-01-01

334

Preparation of porous hydrolyzable polyrotaxane hydrogels and their erosion behavior.  

PubMed

We have prepared porous polyrotaxane hydrogels by using the salt leaching technique. Porous hydrogels were found to have a uniform and highly porous structure. The size of pores in each hydrogel was directly proportional to the size of the sodium chloride particle used. Structural uniformity of the hydrogels is useful not only for uniform cell distribution, but also for well-controlled material properties. Uniform pore size and distribution may ensure the diffusion of nutrients throughout of the gel and the removal of metabolic wastes from the system. The results of an erosion study in phosphate-buffered saline showed that the erosion time of porous polyrotaxane hydrogels was controlled by the poly(ethylene glycol) (PEG) content in the hydrogels. The erosion time of the porous polyrotaxane hydrogel was observed to be almost the same with the non-porous polyrotaxane hydrogel with the same PEG content. From the erosion study, the erosion time of the polyrotaxane hydrogel may be independent of its morphology. Easy control of the erosion time in the polyrotaxane hydrogels is useful in the preparation of scaffolds for tissue engineering. PMID:12901438

Ichi, Takahiro; Nitta, Kana; Lee, Won Kyu; Ooya, Tooru; Yui, Nobuhiko

2003-01-01

335

Bank erosion in cold regions  

SciTech Connect

River and lake bank erosion is caused by multiple processes and influenced by many conditions that interact in complex ways. Their importance will vary spatially and temporally due in large part to regional and seasonal differences in climate, hydrology and soils. In cold areas, these normally complex interactions are further complicated because the same process or condition may cause erosion at one time and prevent erosion at another. Bank sediments when frozen may be more resistant to erosion than when unfrozen. However, during the process of freezing, soil structure can be disrupted and sediment pore water can be drawn to the freezing zone within the soil; ice formation may make bank sediment more susceptible to erosion during spring thaw. Ice that has been forced onto and piled upon a shore by wind or thermal expansion can cause considerable localized damage and yet can also protect shores against winter waves and nearshore currents. Ice push can form sediment ramparts that protect the toe of a bank. Spray from winds and waves can freeze to banks, covering them with a protective layer of ice. When river or lake water levels are high enough, however, ice can erode banks by shoving, gouging and disrupting bank sediment. This paper reviews the state of knowledge regarding the importance of cold regions factors in determining the erodibility and erosion of bank sediments. Ongoing investigations to improve methods of erosion prediction in cold climates will also be detailed.

Gatto, L.W. (Army Cold Regions Research and Engineering Lab., Hanover, NH (United States). Geological Sciences Branch)

1993-03-01

336

Proceedings of the 2009 American Control Conference, St. Louis, MO, June 2009 Formation shape and orientation control using projected collinear  

E-print Network

and orientation control using projected collinear tensegrity structures Darren Pais, Ming Cao and Naomi Ehrich and rigidity properties inherent to tensegrity struc- tures, we first design a tensegrity-based, globally to stabilize a planar shape for a group of N vehicles using virtual tensegrity structures, where each vehicle

Leonard, Naomi

337

A Manual of Mosquito Control Projects and Committee Assignments for 4-H and Scouts Biology Class Projects, Organized Community Service Programs, and Individuals Interested in Environmental Management.  

ERIC Educational Resources Information Center

The mosquito control projects presented in this manual were prepared from an educational viewpoint and are intended for use by students in 4-H and Scouts and as a supplement to high school and college biology course work. The major emphasis of the projects is on integrated pest management, an approach utilizing cost-effective control methods which…

Hart, Richard A.

338

High velocity erosion of metal interfaces  

SciTech Connect

A unique impact recovery experiment in which a truncated right conic section of 4340 steel is shot through a matching hole in a multi-material target has been used to study the high-velocity erosion of metal surfaces. A variety of metal alloys were examined, covering a wide range of both physical and mechanical properties. Projectile/target pairs of 15 and 30/sup 0/ cone angle have been impacted at 1.12 km/sec. The differences observed in the level of plastic deformation present in the target sections are attributable to target strength, impedance, and melt temperature. These experiments have been analyzed using metallographic examination and numerical simulation to characterize the extent and mode of near-surface deformation. The experiments lend insight into the nature of metal surface impacts and the physical/mechanical parameters which control metal erosion.

Bourcier, R.J.; Chhabildas, L.C.

1987-01-01

339

High Voltage TAL Erosion Characterization  

NASA Technical Reports Server (NTRS)

Extended operation of a D-80 anode layer thruster at high voltage was investigated. The thruster was operated for 1200 hours at 700 Volts and 4 Amperes. Laser profilometry was employed to quantify the erosion of the thruster's graphite guard rings and electrodes at 0, 300, 600, 900, and 1200 hours. Thruster performance and electrical characteristics were monitored over the duration of the investigation. The guard rings exhibited asymmetric erosion that was greatest in the region of the cathode. Erosion of the guard rings exposed the magnet poles between 600 to 900 hours of operation.

Jacobson, David T.

2003-01-01

340

Comment [on “Sea level rise shown to drive coastal erosion  

USGS Publications Warehouse

In a recent article (Eos, Trans., AGU, February 8, 2000, p.55), Leatherman et al. [2000] state that they have confirmed an association between sea-level rise and coastal erosion. Applying their results to the New Jersey, Delaware, and Maryland coasts and using a projected sea-level rise, the authors predict that by 2050 the shoreline will recede 60 m, about two times the average beach width. However, Leatherman et al. [2000] have not convincingly quantified a relationship between sea-level rise and shoreline erosion.We do not agree with their rationale for subsetting their data, and they have not considered other explanations for a background erosion along the U.S. east coast. Furthermore, their future projections are not supported by their analyses.

Sallenger, Asbury H., Jr.; Morton, Robert; Fletcher, Charles; Thieler, E. Robert; Howd, Peter

2000-01-01

341

Analytics and Transactive Control Design for the Pacific Northwest Smart Grid Demonstration Project  

Microsoft Academic Search

We have embarked on a comprehensive smart grid demonstration project in the Pacific Northwest involving 60,000 customers from 12 utilities across 5 states, covering the end-to-end electrical system from generation to consumption, built around a substantial infrastructure of deployed smart meters. The goal of this project is to demonstrate among other things how transactive control can be used to manage

Pu Huang; Jayant Kalagnanam; Ramesh Natarajan; Mayank Sharma; Ron Ambrosio; Don Hammerstrom; Ron Melton

2010-01-01

342

The erosion of citizenship.  

PubMed

The Marshallian paradigm of social citizenship has been eroded because the social and economic conditions that supported postwar British welfare consensus have been transformed by economic and technological change. This article argues that effective entitlement was based on participation in work, war and reproduction, resulting in three types of social identity: worker-citizens, warrior-citizens and parent-citizens. The casualization of labour and the technological development of war have eroded work and war as routes to active citizenship. Social participation through reproduction remains important, despite massive changes to marriage and family as institutions. In fact the growth of new reproductive technologies have reinforced the normative dominance of marriage as a social relation. These rights of reproduction are described as 'reproductive citizenship'. The article also considers the role of voluntary associations in Third-Way strategies as sources of social cohesion in societies where social capital is in decline, and argues that the voluntary sector is increasingly driven by an economic logic of accumulation. With the erosion of national citizenship, Marshall's three forms of rights (legal, political and social) have been augmented by rights that are global, namely environmental, aboriginal and cultural rights. These are driven by global concerns about the relationship between environment, community and body such that the quest for social security has been replaced by concerns for ontological security. PMID:11440053

Turner, B S

2001-06-01

343

Runoff mapping using WEPP erosion model and GIS tools  

NASA Astrophysics Data System (ADS)

Soil erosion, associated with environmental impacts and crop productivity loss, is usually considered the most impacting of surface hydrology processes. Runoff plays a major role in the erosion process, but it is also important by itself as it directly influences several surface hydrologic processes. In this paper, a computer interface (Erosion Database Interface, EDI) is described that allows processing the surface hydrology output database of the Water Erosion Prediction Project (WEPP) erosion prediction model, resulting in a georeferenced estimation of runoff. WEPP output contains non-georeferenced daily information about estimated runoff at the lower end of each Overland Flow Element. EDI, when running with WEPP, allows extracting WEPP-calculated runoff values, transforming them into annual means and relocating them in a georeferenced database readable by Geographic Information Systems (GIS). EDI was applied to a 1990 ha watershed in southeast Brazil, with vegetation of mainly sugarcane, forest, and pasture. A 100-year climate simulation was used as input to WEPP, and erosion values were calculated at about six points per hectare and interpolated to a raster format. EDI was successful in preparing the database for automatic calculation of erosion and hydrologic parameters with WEPP and to restore georeferences to mean annual accumulated runoff data that were imported in the GIS as a vector database. Of all the resulting maps, the runoff map is the one that integrates all of the input parameters required for WEPP simulation, thus reflecting not only the physical environment but also crop growth and management and tillage operations. A very small correlation between runoff and erosion shows them to behave independently. Moreover, it is concluded that on analyzing runoff related to agricultural management, georeferenced runoff studies are especially important. In this context, EDI may be a useful tool to assess the effect of tillage and crop management on runoff production.

de Jong van Lier, Quirijn; Sparovek, Gerd; Flanagan, Dennis C.; Bloem, Elke M.; Schnug, Ewald

2005-12-01

344

Lessons Learned and Flight Results from the F15 Intelligent Flight Control System Project  

NASA Technical Reports Server (NTRS)

A viewgraph presentation on the lessons learned and flight results from the F15 Intelligent Flight Control System (IFCS) project is shown. The topics include: 1) F-15 IFCS Project Goals; 2) Motivation; 3) IFCS Approach; 4) NASA F-15 #837 Aircraft Description; 5) Flight Envelope; 6) Limited Authority System; 7) NN Floating Limiter; 8) Flight Experiment; 9) Adaptation Goals; 10) Handling Qualities Performance Metric; 11) Project Phases; 12) Indirect Adaptive Control Architecture; 13) Indirect Adaptive Experience and Lessons Learned; 14) Gen II Direct Adaptive Control Architecture; 15) Current Status; 16) Effect of Canard Multiplier; 17) Simulated Canard Failure Stab Open Loop; 18) Canard Multiplier Effect Closed Loop Freq. Resp.; 19) Simulated Canard Failure Stab Open Loop with Adaptation; 20) Canard Multiplier Effect Closed Loop with Adaptation; 21) Gen 2 NN Wts from Simulation; 22) Direct Adaptive Experience and Lessons Learned; and 23) Conclusions

Bosworth, John

2006-01-01

345

Overview of implementing a project control system in the nuclear utility industry  

SciTech Connect

During the late 1980s, a metamorphosis began at Florida Power and Light Company (FPL). A strategic step in nuclear engineering's efforts to become more cost effective began in January 1990. A project control department was formed. The initial mission was to provide support for nuclear engineering design activities associated with FPL's two twin-unit nuclear power generation facilities - Turkey Point and St. Lucie. Later, the goal expanded to include the division's materials management, nuclear licensing, and information management departments. The project control group was organized along the lines of the organizations served. Separate dedicated groups were established for each plant. Since most engineering activity was based at the Juno Beach headquarters, the project control staff also was based there.

Cooprider, D.H. (Pacific Inst. of Seattle, WA (United States))

1994-03-01

346

An holistic approach to beach erosion vulnerability assessment.  

PubMed

Erosion is a major threat for coasts worldwide, beaches in particular, which constitute one of the most valuable coastal landforms. Vulnerability assessments related to beach erosion may contribute to planning measures to counteract erosion by identifying, quantifying and ranking vulnerability. Herein, we present a new index, the Beach Vulnerability Index (BVI), which combines simplicity in calculations, easily obtainable data and low processing capacity. This approach provides results not only for different beaches, but also for different sectors of the same beach and enables the identification of the relative significance of the processes involved. It functions through the numerical approximation of indicators that correspond to the mechanisms related to the processes that control beach evolution, such as sediment availability, wave climate, beach morhodynamics and sea level change. The BVI is also intended to be used as a managerial tool for beach sustainability, including resilience to climate change impact on beach erosion. PMID:25123815

Alexandrakis, George; Poulos, Serafim ?

2014-01-01

347

Solid-particle erosion of aluminum/particulate ceramic composites  

SciTech Connect

Impact erosion of 2014 aluminum, 2014 aluminum + 20 vol % particulate silicon carbide, and 2014 aluminum + 20 vol % particulate aluminum oxide has been studied at room temperature. The alloys were tested in the as-received and heat-treated conditions. Experiments were conducted with aluminum oxide abrasive in vacuum in a slinger-type apparatus over a range of abrasive size, velocity, and angle of impact. Erosion rates were influenced by reinforcement and heat treatment. Reduced ductility, both overall and local, attributed to reinforcement or heat treatment, caused, under most conditions, more rapid erosion of the composites. The data suggest that erosion rate can be minimized by proper microstructural control, involving reducing reinforcement segregation and the amount of intermetallic compounds. 37 refs., 7 figs.

Goretta, K.C.; Wu, W.; Routbort, J.L. (Argonne National Lab., IL (USA)); Rohatgi, P.K. (Wisconsin Univ., Milwaukee, WI (USA))

1990-06-01

348

Hydraulic wellbore erosion while drilling  

SciTech Connect

This article is the first to identify nozzle hydraulic effects in a field evaluation of hole erosion. Common practice normally identifies annular velocity as the culprit for excessive hole washout. But field tests in this article clearly identify excessive nozzle hydraulics as the cause for hole erosion. Both oil-based and water-based drilling fluids were used during the field test. The primary contribution of this study is a simple guideline to assist drillers in preventing excessive hole erosion. This article describes drilling conditions and caliper logs, and discusses sequences of events that could explain the observations. Some preliminary guidelines are presented so that drillers can prevent erosion of the wellbore from high shear rates at bit nozzles.

Chemerinski, B. [British Borneo Exploration, Houston, TX (United States); Robinson, L. [OGCI, Houston, TX (United States)

1996-12-01

349

Tooth Abrasion and Tooth Erosion  

MedlinePLUS

... protects the innermost part of the tooth, the pulp, which contains nerves and blood vessels. Abrasion and erosion also can affect how your teeth look. Diagnosis Your dentist can examine your teeth ...

350

The conceptual framework of the International Tobacco Control (ITC) Policy Evaluation Project  

PubMed Central

This paper describes the conceptual model that underlies the International Tobacco Control Policy Evaluation Project (ITC Project), whose mission is to measure the psychosocial and behavioural impact of key policies of the Framework Convention on Tobacco Control (FCTC) among adult smokers, and in some countries, among adult non?smokers and among youth. The evaluation framework utilises multiple country controls, a longitudinal design, and a pre?specified, theory?driven conceptual model to test hypotheses about the anticipated effects of specific policies. The ITC Project consists of parallel prospective cohort surveys of representative samples of adult smokers currently in nine countries (inhabited by over 45% of the world's smokers), with other countries being added in the future. Collectively, the ITC Surveys constitute the first?ever international cohort study of tobacco use. The conceptual model of the ITC Project draws on the psychosocial and health communication literature and assumes that tobacco control policies influence tobacco related behaviours through a causal chain of psychological events, with some variables more closely related to the policy itself (policy?specific variables) and other variables that are more downstream from the policy, which have been identified by health behaviour and social psychological theories as being important causal precursors of behaviour (psychosocial mediators). We discuss the objectives of the ITC Project and its potential for building the evidence base for the FCTC. PMID:16754944

Fong, G T; Cummings, K M; Borland, R; Hastings, G; Hyland, A; Giovino, G A; Hammond, D; Thompson, M E

2006-01-01

351

Chevrons formation in laminar erosion  

NASA Astrophysics Data System (ADS)

When eroded by laminar free-surface flows, granular substrates may generate a rich variety of natural patterns. Among them are dunes, similar to the ones observed by Charru and Hinch in a Couette cell (Charru F, Hinch EJ ; Ripple formation on a particle bed sheared by a viscous liquid. Part 1. Steady flow ; JOURNAL OF FLUID MECHANICS 550: 111-121 MAR 10 2006). Chevron-shaped instabilities as those found on the sea-shore, can also be observed, sometimes in competition against dunes formation. These were first pointed out by Daerr et al. when pulling a plate covered with granular material out of a bath of water (Daerr A, Lee P, Lanuza J, et al. ; Erosion patterns in a sediment layer ; PHYSICAL REVIEW E 67 (6): Art. No. 065201 Part 2 JUN 2003). Both instabilities can grow in laminar open-channel flows, an experimental set-up which is more easily controlled. The mechanisms leading to the formation of these patterns are investigated and compared. Whereas dunes formation requires vertical inertia effects, we show that chevrons may result from the non-linear evolution of bars instability, which may grow even in purely viscous flows.

Devauchelle, Olivier; Josserand, Christophe; Lagree, Pierre-Yves; Zaleski, Stephane; Nguyen, Khanh-Dang; Malverti, Luce; Lajeunesse, Eric

2007-11-01

352

Soil Erosion and Agricultural Sustainability  

NASA Astrophysics Data System (ADS)

Data drawn from a global compilation of studies support the long articulated contention that erosion rates from conventionally plowed agricultural fields greatly exceed rates of soil production, erosion under native vegetation, and long-term geological erosion. Whereas data compiled from around the world show that soil erosion under conventional agriculture exceeds both rates of soil production and geological erosion rates by up to several orders of magnitude, similar global distributions of soil production and geological erosion rates suggest an approximate balance. Net soil erosion rates in conventionally plowed fields on the order of 1 mm/yr can erode typical hillslope soil profiles over centuries to millennia, time-scales comparable to the longevity of major civilizations. Well-documented episodes of soil loss associated with agricultural activities date back to the introduction of erosive agricultural methods in regions around the world, and stratigraphic records of accelerated anthropogenic soil erosion have been recovered from lake, fluvial, and colluvial stratigraphy, as well as truncation of soil stratigraphy (such as truncated A horizons). A broad convergence in the results from studies based on various approaches employed to study ancient soil loss and rates of downstream sedimentation implies that widespread soil loss has accompanied human agricultural intensification in examples drawn from around the world. While a broad range of factors, including climate variability and society-specific social and economic contexts — such as wars or colonial relationships — all naturally influence the longevity of human societies, the ongoing loss of topsoil inferred from studies of soil erosion rates in conventional agricultural systems has obvious long-term implications for agricultural sustainability. Consequently, modern agriculture — and therefore global society — faces a fundamental question over the upcoming centuries. Can an agricultural system capable of feeding a growing population safeguard both soil fertility and the soil itself? Although the experiences of past societies provide ample historical basis for concern about the long-term prospects for soil conservation, data compiled from recent studies indicate that no-till farming could reduce erosion to levels close to soil production rates. Consequently, agricultural production need not necessarily come at the expense of either soil fertility or the soil itself, even if recent proposals to rely on conventionally grown corn for biofuels exemplify how short-term social and economic trade-offs can de-prioritize soil conservation. Like the issues of climate change and loss of biodiversity, the ongoing global degradation and loss of soil presents a fundamental social challenge in which the slow pace of environmental change counter-intuitively makes solutions all the more difficult to adopt.

Montgomery, D. R.

2009-04-01

353

The erosive effects of racism: reduced self-control mediates the relation between perceived racial discrimination and substance use in African American adolescents.  

PubMed

Perceived racial discrimination, self-control, anger, and either substance use or use cognitions were assessed in 2 studies conducted with samples of African American adolescents. The primary goal was to examine the relation between discrimination and self-control over time; a 2nd goal was to determine whether that relation mediates the link between discrimination and substance use found in previous research. Study 1, which included a latent growth curve analysis with 3 waves of data, indicated that experience with discrimination (from age 10 years to age 18 years) was associated with reduced self-control, which then predicted increased substance use. Additional analyses indicated anger was also a mediator of this discrimination to use relation. Study 2, which was experimental, showed that envisioning an experience involving discrimination was associated with an increase in substance-related responses to double entendre words (e.g., pot, roach) in a word association task, especially for participants who were low in dispositional self-control. The effect was again mediated by reports of anger. Thus, the "double mediation" pattern was discrimination ? more anger and reduced self-control ? increased substance use and/or substance cognitions. Results are discussed in terms of the long-term impact of discrimination on self-control and health behavior. Implications for interventions aimed at ameliorating the negative effects of discrimination and low self-control on health are also discussed. PMID:22390225

Gibbons, Frederick X; O'Hara, Ross E; Stock, Michelle L; Gerrard, Meg; Weng, Chih-Yuan; Wills, Thomas A

2012-05-01

354

The Erosive Effects of Racism: Reduced Self-control Mediates the Relation between Perceived Racial Discrimination and Substance Use in African American Adolescents  

PubMed Central

Perceived racial discrimination, self-control, anger, and either substance use or use cognitions were assessed in two studies conducted with samples of African American adolescents. The primary goal was to examine the relation between discrimination and self-control over time; a second goal was to determine if that relation mediates the link between discrimination and substance use found in previous research. Study 1, which included a latent growth curve analysis with three waves of data, indicated that experience with discrimination (from age 10 to age 18) was associated with reduced self-control, which then predicted increased substance use. Additional analyses indicated anger was also a mediator of this discrimination to use relation. Study 2, which was experimental, showed that envisioning an experience involving discrimination was associated with an increase in substance-related responses to double entendre words (e.g., “pot,” “roach”) in a word association task, especially for participants who were low in dispositional self-control. The effect was again mediated by reports of anger. Thus, the “double mediation” pattern was: discrimination ? more anger and reduced self-control ? increased substance use and/or substance cognitions. Results are discussed in terms of the long-term impact of discrimination on self-control and health behavior. Implications for interventions aimed at ameliorating the negative effects of discrimination and low self-control on health are also discussed. PMID:22390225

Gibbons, Frederick X.; O'Hara, Ross E.; Stock, Michelle L.; Gerrard, Meg; Weng, Chih-Yuan; Wills, Thomas A.

2012-01-01

355

A Wind Erosion Equation1  

Microsoft Academic Search

ABSTRACT The amount of erosion, E, expressed in tons per acre per annum, that will occur from a given agricultural field can be expressed in terms of equivalent variables as: E = , is field length along the prevailing wind erosion direction, and V is equivalent quantity of vegetative cover. The 5 equivalent variables are obtained,by grouping,some,and,converting,others of the,11 primary

N. P. Woodruff; F. H. Siddoway

1965-01-01

356

Test Your Stream Erosion IQ  

NSDL National Science Digital Library

Test Your Stream Erosion IQ is an online activity for students to examine topographical maps of stream erosion, and identify the type of landforms that would be created by the stream channels shown on the maps. From the elevation contour lines, students decide if the dome, mountain peak, U-shaped canyon, irregular, or V-shaped canyon landforms are represented. There are also photographs to illustrate the landforms.

357

Experimental evidence for bedrock erosion by suspended sediment  

NASA Astrophysics Data System (ADS)

Fluvial bedrock incision influences channel evolution and sets the pace of landscape lowering. Bedrock incision often occurs via abrasion, and existing theory is divided on the erosional efficiency of sediment transported in suspension versus bed load, due in part to a lack of data to test model predictions. This represents a major knowledge gap as suspended sediment can account for the majority of the total fluvial sediment load, and untested models make opposite predictions of bedrock erosion in steep channels and during large floods. We performed controlled abrasion mill experiments examining suspended and bed load erosion, making use of an erodible polyurethane foam substrate as a bedrock analog to overcome previous experimental limitations and allow for measureable suspension erosion. Our results show foam erodes similar to natural rock, where erodibility is a function of tensile strength and density. To explore the role of the mode of sediment transport on erosion, we varied sediment size from gravel (42 mm diameter) to medium sand (0.4 mm diameter), while holding fixed hydraulics, sediment load, and substrate strength. Under these conditions, volumetric erosion rates decreased across the bed load (~101 - 103 cm3/hr) to suspended load (~0.01 - 100 cm3/hr) transition due to lower near-bed sediment concentrations (~25 g/l vs. 115 g/l), slower settling velocity (0.09 m/s vs. 0.49 m/s), and viscous damping of impacts (for particle Stokes numbers less than ~75) for suspended particles. Our results provide direct experimental evidence of erosion by suspended load, and upscaling results to field scale shows suspension erosion can outpace bed load erosion by up to a factor ~4 during large floods which suspend coarse sand and gravel, and where suspended sediment dominates the total load. These results imply that suspension erosion may also dominate on very steep slopes where commonly used bedrock incision models (which ignore suspension erosion) predict zero erosion. For small floods and low sloping channels where suspension is limited to sand, suspension erosion will have a reduced role because of comparatively low impact energies and viscously damped collisions.

Scheingross, J. S.; Brun, F.; Lo, D. Y.; Omerdin, K.; Lamb, M. P.

2013-12-01

358

Stimulation Controls and Mitigation of Induced Seismicity for EGS Project: Examples from the Newberry EGS Demonstration Project (Invited)  

NASA Astrophysics Data System (ADS)

Creating an EGS reservoir depends upon injection induced seismicity (IIS) to create fracture permeability and allow the reservoir to be mapped using passive microseismic monitoring. However, in some cases, the seismicity induced through the stimulation has been felt by surrounding populations and in one case caused sufficient concern to force shut-down of the project. AltaRock Energy, Inc. is working with universities, national labs and consultants on the Newberry Volcano EGS Demonstration Project (Funded in part through a grant from the US DOE: DE-EE0002777). This project will attempt to stimulate a very low permeability existing deep geothermal well with high temperature to develop a circulating geothermal system that be able to sustain production of economic quantities of hot water and steam for power production. In order to allay concerns that IIS might become hazardous at Newberry, AltaRock Energy has agreed to a robust series of safeguards and mitigation controls. The safeguards detail how the EGS stimulation will be monitored and under what circumstances the stimulation should be safely reduced or halted to avoid perceptible seismic events that would alarm or possibly cause damage to the local community. The International Energy Agency (IEA) Implementing Agreement for a Cooperative Programme on Geothermal Energy Research and Technology, or Geothermal Implementing Agreement (GIA), developed an induced seismicity mitigation protocol which has been adopted by the US Department of Energy for their funded EGS Demonstration Projects. AltaRock is the process of making this protocol site specific for the Newberry project.The Notice of Intent (NOI) to the BLM for the Newberry EGS Demonstration includes plans to conduct an induced seismicity hazards and risk assessment. These plans include implementing the Protocol for Induced Seismicity Associated with Geothermal System (Majer et al., 2008), adopted by the International Energy Agency. The theory of IIS has recently advanced due to the data and experience collected at EGS projects worldwide. One of the most promising areas of research has been the development of a seismogenic index by Dr. Serge Shapiro and colleagues at Freie Universität Berlin. This index (Table 1) may provide a means to relate measurable geomechanical parameters and total injected volume to the probability of generating a seismic event with a magnitude greater than a tolerable threshold.Table 1: Seismogenic Indices 1Estimated from Figure 3 of Shapiro et al. (2010). 2Values will be determined for other sites based on additional data gathering, sensitivity analysis and consultation with Dr. Shapiro.

Petty, S.; Cladouhos, T. T.; Osborn, W.; Iovenitti, J.

2010-12-01

359

Monitoring Coastal Erosion Natural Resilience by Indexing Coastal Dunes State  

Microsoft Academic Search

SUMMARY The paper describes the results outcoming from a study done inside a Life Environment SELSY Project. Along Puglia littoral (southern Italy) the coastal susceptibility to erosion and dune state have been quantitatively evaluated, A complex complex database has been built and this will be available to local Public Administrations. The database contains, and relates, information that make possible, through

Valpreda Edi; Gragnaniello Simona; Rotunno Michele

360

Control of Major-Accident Hazards Involving Land Transmission Charlotte BOUISSOU, Project Manager for Pipelines Risk Assessment  

E-print Network

Control of Major-Accident Hazards Involving Land Transmission Pipelines Charlotte BOUISSOU, Project Nicolas DECHY, Project Manager for Accidents Analysis and Learning from Experience Contact : charlotte, this Directive does not apply to land transmission pipelines... According to several accidents analysis

Paris-Sud XI, Université de

361

CRC handbook of coastal processes and erosion  

SciTech Connect

This text includes the following contents: Beach Processes - Erosion - An Introduction. Edge Waves and the Configuration of the Shoreline. Morphodynamics of Beaches and Surf Zones in Australia. The Erosion of Siletz Spit, Oregon. Barrier Islands. Patterns and Prediction of Shoreline Change. Models for Beach Profile Response. Erosion on the Great Lakes Due to Changes in the Water Level. Coastal Erosion in Response to the Construction of Jetties and Breakwaters. Computer Models of Shoreline Changes. Principles of Beach Nourishment. Processes of Sea Cliff and Platform Erosion. Beach Processes and Sea Cliff Erosion in San Diego County, California. Erosion of the United States Shoreline. Index.

Komar, P.D.

1983-01-01

362

Controllable 3D Display System Based on Frontal Projection Lenticular Screen  

NASA Astrophysics Data System (ADS)

A novel auto-stereoscopic three-dimensional (3D) projection display system based on the frontal projection lenticular screen is demonstrated. It can provide high real 3D experiences and the freedom of interaction. In the demonstrated system, the content can be changed and the dense of viewing points can be freely adjusted according to the viewers' demand. The high dense viewing points can provide smooth motion parallax and larger image depth without blurry. The basic principle of stereoscopic display is described firstly. Then, design architectures including hardware and software are demonstrated. The system consists of a frontal projection lenticular screen, an optimally designed projector-array and a set of multi-channel image processors. The parameters of the frontal projection lenticular screen are based on the demand of viewing such as the viewing distance and the width of view zones. Each projector is arranged on an adjustable platform. The set of multi-channel image processors are made up of six PCs. One of them is used as the main controller, the other five client PCs can process 30 channel signals and transmit them to the projector-array. Then a natural 3D scene will be perceived based on the frontal projection lenticular screen with more than 1.5 m image depth in real time. The control section is presented in detail, including parallax adjustment, system synchronization, distortion correction, etc. Experimental results demonstrate the effectiveness of this novel controllable 3D display system.

Feng, Q.; Sang, X.; Yu, X.; Gao, X.; Wang, P.; Li, C.; Zhao, T.

2014-08-01

363

UrbanSolutionsCenter Johne's Disease Control Demonstration Project for the Texas Dairy and  

E-print Network

UrbanSolutionsCenter Johne's Disease Control Demonstration Project for the Texas Dairy and Beef in some regions of the country, progress remains slow. Most of the success of the program for dairy herds of the country, dairy herds are much larger (averaging over 400 head per herd in Texas) and are frequently

364

Project T.E.A.M. (Technical Education Advancement Modules). Advanced Statistical Process Control.  

ERIC Educational Resources Information Center

This instructional guide, one of a series developed by the Technical Education Advancement Modules (TEAM) project, is a 20-hour advanced statistical process control (SPC) and quality improvement course designed to develop the following competencies: (1) understanding quality systems; (2) knowing the process; (3) solving quality problems; and (4)…

Dunlap, Dale

365

Project T.E.A.M. (Technical Education Advancement Modules). Introduction to Statistical Process Control.  

ERIC Educational Resources Information Center

This instructional guide, one of a series developed by the Technical Education Advancement Modules (TEAM) project, is a 6-hour introductory module on statistical process control (SPC), designed to develop competencies in the following skill areas: (1) identification of the three classes of SPC use; (2) understanding a process and how it works; (3)…

Billings, Paul H.

366

University of Nevada Las Vegas Arduino Project Report: Fan Speed Control as a Function of Thermistor  

E-print Network

University of Nevada Las Vegas Arduino Project Report: Fan Speed Control as a Function, and an arduino board. The arduino board is programmed to read the analog input, the thermistor, and respond by the arduino that will decrease the speed of the fan. Furthermore, if the temperature goes up, the resistance

Kachroo, Pushkin

367

Resilient Propulsion Control Research for the NASA Integrated Resilient Aircraft Control (IRAC) Project  

NASA Technical Reports Server (NTRS)

Gas turbine engines are designed to provide sufficient safety margins to guarantee robust operation with an exceptionally long life. However, engine performance requirements may be drastically altered during abnormal flight conditions or emergency maneuvers. In some situations, the conservative design of the engine control system may not be in the best interest of overall aircraft safety; it may be advantageous to "sacrifice" the engine to "save" the aircraft. Motivated by this opportunity, the NASA Aviation Safety Program is conducting resilient propulsion research aimed at developing adaptive engine control methodologies to operate the engine beyond the normal domain for emergency operations to maximize the possibility of safely landing the damaged aircraft. Previous research studies and field incident reports show that the propulsion system can be an effective tool to help control and eventually land a damaged aircraft. Building upon the flight-proven Propulsion Controlled Aircraft (PCA) experience, this area of research will focus on how engine control systems can improve aircraft safe-landing probabilities under adverse conditions. This paper describes the proposed research topics in Engine System Requirements, Engine Modeling and Simulation, Engine Enhancement Research, Operational Risk Analysis and Modeling, and Integrated Flight and Propulsion Controller Designs that support the overall goal.

Guo, Ten-Huei; Litt, Jonathan S.

2007-01-01

368

Restorative therapy of erosive lesions.  

PubMed

When substance loss caused by erosive tooth wear reaches a certain degree, oral rehabilitation becomes necessary. Until some 20 years ago, the severely eroded dentition could only be rehabilitated by the provision of extensive crown and bridge work or removable overdentures. As a result of the improvements in resin composite restorative materials, and in adhesive techniques, it has become possible to rehabilitate eroded dentitions in a less invasive manner. However, even today advanced erosive destruction requires the placement of more extensive restorations such as overlays and crowns. It has to be kept in mind that the etiology of the erosive lesions needs to be determined in order to halt the disease, otherwise the erosive process will continue to destroy tooth substance. This overview presents aspects concerning the restorative materials as well as the treatment options available to rehabilitate patients with erosive tooth wear, from minimally invasive direct composite reconstructions to adhesively retained all-ceramic restorations. Restorative treatment is dependent on individual circumstances and the perceived needs and concerns of the patient. Long-term success is only possible when the cause is eliminated. In all situations, the restorative preparations have to follow the principles of minimally invasive treatment. PMID:24993273

Peutzfeldt, Anne; Jaeggi, Thomas; Lussi, Adrian

2014-01-01

369

Processes of barrier island erosion  

SciTech Connect

During 1986, the US Geological Survey and the Louisiana Geological Survey began a 5-year study of the processes causing the extreme rates (up to 20 m/year) of erosion of Louisiana's barrier islands. These processes must be better understood in order to predict future erosion and to assess management and erosion mitigation plans. The study is divided into three parts: the geologic development of barrier islands, the critical processes leading to erosion, and applications of results. This paper provides an overview of the part of the study on critical processes. The process part includes modeling erosion of the barrier islands due to sea level rise, the net loss of sand offshore, gradients in longshore transport, and overwash. Evidence indicates that the low-lying barrier beaches on much of the Louisiana coast do not approach an equilibrium configuration. These beaches, which, in many places, are not protected by dunes, are overwashed even during moderate storms and apparently are not evolving to a configuration that limits overwash. As a result, even with stable sea level, the beaches will continue to overwash and migrate landward during storms. Commonly used methods of modeling beach response to rising sea level assume beaches approach an equilibrium configuration, hence applying these methods to coastal Louisiana is problematical.

Sallenger, A.H. Jr. (Geological Survey, St. Petersburg, FL (USA)); Williams, S.J. (Geological Survey, Reston, VA (USA))

1989-09-01

370

Surface Erosion and Flow  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 7 April 2003

The mottled surface texture and flow features observed in this THEMIS image suggest materials may be, or have been, mixed with ice. There is also evidence in some areas for infilling of sediments as crater rims and ridges appear covered.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Image information: VIS instrument. Latitude 45.3, Longitude 48.8 East (311.2 West). 19 meter/pixel resolution.

2003-01-01

371

BCAUS Project description and consideration of separation of data and control  

NASA Technical Reports Server (NTRS)

The commonly stated truths that data may be segregated from program control in generic expert system shells and that such tools support straightforward knowledge representation were examined. The ideal of separation of data from program control in expert systems is difficult to realize for a variety of reasons. One approach to achieving this goal is to integrate hybrid collections of specialized shells and tools instead of producing custom systems built with a single all purpose expert system tool. Aspects of these issues are examined in the context of a specific diagnostic expert system application, the Backup Control Mode Analysis and Utility System (BCAUS), being developed for the Gamma Ray Observatory (GRO) spacecraft. The project and the knowledge gained in working on the project are described.

Bush, Joy L.; Weaver, Steven J.

1989-01-01

372

The shape and erosion of pebbles  

E-print Network

The shapes of flat pebbles may be characterized in terms of the statistical distribution of curvatures measured along their contours. We illustrate this new method for clay pebbles eroded in a controlled laboratory apparatus, and also for naturally-occurring rip-up clasts formed and eroded in the Mont St.-Michel bay. We find that the curvature distribution allows finer discrimination than traditional measures of aspect ratios. Furthermore, it connects to the microscopic action of erosion processes that are typically faster at protruding regions of high curvature. We discuss in detail how the curvature may be reliable deduced from digital photographs.

D. J. Durian; H. Bideaud; P. Duringer; A. Schroder; C. M. Marques

2006-07-05

373

Examine an example of wave erosion  

NSDL National Science Digital Library

This series of photographs presents an example of wave erosion to middle and high school students. The five images, dated from 1890 to 1990, depict the demise of an actual sea stack near Newport, Oregon. The introduction explains how sea stacks begin as part of an outcropping of land such as a cliff and how they are gradually eroded by the waves. A pop-up window shows the location the original sea stack on a map of the United States. Movie controls allow students to repeat or pause the succession of images, which can give students more time to analyze and compare the images. Copyright 2005 Eisenhower National Clearinghouse

Education, Terc. C.; Littell, Mcdougal

2003-01-01

374

Composite Erosion by Computational Simulation  

NASA Technical Reports Server (NTRS)

Composite degradation is evaluated by computational simulation when the erosion degradation occurs on a ply-by-ply basis and the degrading medium (device) is normal to the ply. The computational simulation is performed by a multi factor interaction model and by a multi scale and multi physics available computer code. The erosion process degrades both the fiber and the matrix simultaneously in the same slice (ply). Both the fiber volume ratio and the matrix volume ratio approach zero while the void volume ratio increases as the ply degrades. The multi factor interaction model simulates the erosion degradation, provided that the exponents and factor ratios are selected judiciously. Results obtained by the computational composite mechanics show that most composite characterization properties degrade monotonically and approach "zero" as the ply degrades completely.

Chamis, Christos C.

2006-01-01

375

LOUISIANA BARRIER ISLAND EROSION STUDY.  

USGS Publications Warehouse

During 1986, the U. S. Geological Survey and the Louisiana Geological Survey began a five-year cooperative study focused on the processes which cause erosion of barrier islands. These processes must be understood in order to predict future erosion and to better manage our coastal resources. The study area includes the Louisiana barrier islands which serve to protect 41% of the nation's wetlands. These islands are eroding faster than any other barrier islands in the United States, in places greater than 20 m/yr. The study is divided into three parts: geological development of barrier islands, quantitative processes of barrier island erosion and applications of results. The study focuses on barrier islands in Louisiana although many of the results are applicable nationwide.

Sallenger, Jr. , Asbury, H.; Penland, Shea; Williams, S. Jeffress; Suter, John, R.

1987-01-01

376

WATER INFILTRATION CONTROL TO ACHIEVE MINE WATER POLLUTION CONTROL: THE DENTS RUN WATERSHED DEMONSTRATION PROJECT  

EPA Science Inventory

The objective of this study was to demonstrate the effectiveness of surface mined land reclamation measures in establishing surface water infiltratin control to prevent or reduce pollution from acid mine drainage. The Dents Run watershed, located in Monongalia County, West Virgin...

377

Channels and Erosion  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 20 June 2003

The dissected and eroded channel observed in this THEMIS image taken of plains materials southwest of the volcano Elysium Mons shows typical erosional islands and depositional features. The interesting thing about this channel is that it appears to start out of nowhere. The MOLA context image shows that the channel originates from a fissure within the ground, whose origin is likely volcanic, but may also be related to volatile processes.

Image information: VIS instrument. Latitude 19.5, Longitude 126.8 East (233.2 West). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2003-01-01

378

Deposition + Erosion = Textures  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site]

Released 7 May 2003

Toward the westernmost extent of the Medusae Fossae Formation, a 5000+ km long belt of eroding sediments, the interleaving of erosional surfaces produces dramatic textural variations. In the lower third of this image, the cross-hatched MFF layer is being stripped back from a surface that was already heavily eroded before the MFF layer was deposited. Also, note the sinuous and, in places, dendritic ridges that are either linear dunes or inverted channels.

Image information: VIS instrument. Latitude -3.9, Longitude 154.1East (205.9). 19 meter/pixel resolution.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2003-01-01

379

Combating tropical infectious diseases: report of the Disease Control Priorities in Developing Countries Project.  

PubMed

Infectious diseases are responsible for >25% of the global disease toll. The new Disease Control Priorities in Developing Countries Project (DCPP) aims to decrease the burden of these diseases by producing science-based analyses from demographic, epidemiologic, disease intervention, and economic evidence for the purpose of defining disease priorities and implementing control measures. The DCPP recently reviewed selected tropical infectious diseases, examined successful control experiences, and defined unsettled patient treatment, prevention, and research issues. Disease elimination programs against American trypanosomiasis (Chagas disease), onchocerciasis, lymphatic filariasis, leprosy, trachoma, and measles are succeeding. Dengue, leishmaniasis, African trypanosomiasis, malaria, diarrheal diseases, helminthic infections, and tuberculosis have reemerged because of inadequate interventions and control strategies and the breakdown of health delivery systems. Application of technologies must be cost-effective and intensified research is essential if these and other scourges are to be controlled or eliminated in the 21st century. PMID:14999633

Hotez, Peter J; Remme, Jan H F; Buss, Paulo; Alleyne, George; Morel, Carlos; Breman, Joel G

2004-03-15

380

CSE 4360 / 5364 -Autonomous Robots Project 2: Behavior-based Robot Control CSE 4360 / 5364 -Autonomous Robots  

E-print Network

CSE 4360 / 5364 - Autonomous Robots Project 2: Behavior-based Robot Control CSE 4360 / 5364 - Autonomous Robots Project 2- Spring 2014 Due Date: April 22 2014, 5:00 pm Behavior-based Fire Alarm Robot The goal of this project is to design a behavior-based fire detection robot that is able to move from

Huber, Manfred

381

Rain Erosion-Does the Rate of Water Effect Erosion?  

NSDL National Science Digital Library

This activity is a guided inquiry investigation where students gather data on rate of water falling on erosion. Student will interpret their data, and develop a conclusion from the data. The data will lead to further questions, which can be developed by the students.

Johnson, Kyle

382

An Economic Analysis of Erosion and Sediment Damage in the Lower Running Draw Watershed  

E-print Network

of a study on the economic impact of implementing potential agricultural NPS pollution controls in Lower Running Water Draw watershed. The study focuses on: (a) the effects of erosion control on farm income, (b) off-site sediment damages...

Reneau, D. R.; Taylor, C. R.; Harris, B. L.; Lacewell, R. D.; Mueller, P. E.

383

An Economic Analysis of Erosion and Sedimentation in Lavon Reservoir Watershed  

E-print Network

potential agricultural NPS pollution controls in the watershed above Lavon Reservoir. The study focuses on: (a) effects of erosion controls on farm income, (b) off-side sediment damages in the watersheds; (c) costs of administering and enforcing alternative...

Taylor, C. R.; Reneau, D. R.; Harris, B. L.

384

An investigation on erosion behavior of HVOF sprayed WC-CoCr coatings  

NASA Astrophysics Data System (ADS)

Present work is an investigation of slurry erosion behavior of WC-CoCr cermet coatings deposited with two different WC grain sizes. HVOF thermal spray process was employed due to its high velocity and low flame temperature characteristics resulting in quality coating. HVOF spraying was assisted with in-flight particle temperature and velocity measurement system to control its heating. Slurry erosion testing was performed using a pot-type slurry erosion tester to evaluate slurry erosion resistance of the coatings. Two parameters were considered for testing viz. erodent particle size and slurry concentration. Surface morphology was examined using SEM images and phase identification was done by XRD. The erosion behavior and mechanism of material removal was studied and discussed based on microstructural examination. It was observed that WC-CoCr cermet coating deposited with fine grain WC exhibits higher slurry erosion resistance under all testing conditions as compared to conventional cermet coating.

Thakur, Lalit; Arora, N.; Jayaganthan, R.; Sood, R.

2011-11-01

385

Swelling and erosion of pectin matrix tablets and their impact on drug release behavior.  

PubMed

The aim of this study was to investigate swelling and erosion behaviors of hydrophilic matrix tablets using pectin and their impact on drug release. The matrix tablets were prepared by direct compression using different types of pectin. Swelling and erosion studies of pectin matrix tablets were carried out in various media. The pectin matrix tablets formed a continuous gel layer while in contact with the aqueous medium undergoing a combination of swelling and erosion. The swelling action of pectin matrices was controlled by the rate of its hydration in the medium. Release studies showed that the swelling and erosion of matrices influenced the drug release. The extent of matrix swelling, erosion and diffusion of drug determined the kinetics as well as mechanism of drug release from pectin-based matrix tablets. The release data showed a good fit into the power law or the Korsmeyer-Peppas equation indicating the combined effect of diffusion and erosion mechanisms of drug release. PMID:17267193

Sriamornsak, Pornsak; Thirawong, Nartaya; Weerapol, Yossanun; Nunthanid, Jurairat; Sungthongjeen, Srisagul

2007-08-01

386

Mechanisms of cavitation erosion of TiAl-based titanium aluminide intermetallic alloys  

SciTech Connect

The modes and controlling mechanisms of cavitation erosion of plasma arc-melted TiAl-based titanium aluminide intermetallic alloys, Ti-52Al (at.%) and Ti-48Al-2Mn-2Nb (at.%) were studied and compared to those of the Ti{sub 3}Al-based alloy, Ti-25Al-10Nb-3V-1Mo (at.%) and other comparative materials. The accumulation of cavitation damage during the initial stages of cavitation erosion was monitored and the work hardening produced in steady state erosion conditions was measured on 5{degree} taper sections. The cavitation erosion resistance of the titanium cavitation erosion resistance of the TiAl-based titanium aluminide alloys compared to Ti-25Al-10Nb-3V-1Mo (at.%) is ascribed to their ability to twin and their greater work hardening ability during cavitation erosion.

Howard, R.L.; Ball, A. [Univ. of Cape Town, Rondebosch (South Africa). Dept. of Materials Engineering] [Univ. of Cape Town, Rondebosch (South Africa). Dept. of Materials Engineering

1996-08-01

387

Slope erosion estimation in the river basin of the boreal zone of the East Russian Plain  

NASA Astrophysics Data System (ADS)

INTRODUCTION Multi-factor controls of erosion processes determine the complexity of erosion-affected hillslope geosystem functioning. Relationships between erosion and its major controls change in geographical space, so that slope erosion regimes vary regionally, being determined by landscape conditions. Problems with the quantitative assessment of all types of soil erosion from raindrop to gullies still require a satisfactory solution. In this paper we propose to consider the entire complexity of hillslope erosion processes as a unit termed "basin erosion". The focus of this paper is on the methodological aspects of revealing the roles different landscape conditions play in causing basin erosion. The East Russian Plain was chosen as the investigation region due to the wide distribution of a spectrum of erosion processes in the region. It is also where the so-called "Erosion Pole" of European Russia is situated. During the last 200 years arable land cover has increased by 40-60% and now comprises about 80-85% of basins area. The period of most intensive agriculture in the region began about 200 years ago. Different combinations of natural and anthropogenic conditions create geocomplexes of different taxonomic levels known as "landscapes". Depending on the degree to which erosion processes are generalized in an investigation, it is necessary to use different geosystem taxon as the basic unit. To evaluate the role different landscape factors play in the development of human-accelerated basin erosion, a landscape map of the East Russian Plain was created. DATA The study territory is located within the forest, forest-steppe and northern part of steppe landscape zone of the Russian Plain and comprises more than 130 000 km2. The total number of parameters used for landscape regionalization comprised more than 50 (including: hydro-climatic, geomorphological, anthropogenic, lithological and landscape-geophysical); 3331 river basins were examined with an average catchment area of 40 km2. METHODS The method of "self-organizing maps of Kohonen" was used as the main approach for automatic regionalization. RESULTS Spatial analyses of soil erosion and gullying intensity in the study region based on available information allows us to conclude that: maximum basin erosion is characteristic for upland landscapes of broad-leaved forest zones (Sub-boreal) and the southern part of mixed forest zone; its intensity decreases in both western and eastern directions; to the north and to the south from upland landscapes of broad-leaved forest zones we can also observe lowering of basin erosion intensity; in the north it happens because of lower agricultural activity, and to the south it is due to development of chernozem soils more stable to erosion; and zonality is typical for soil erosion processes.

Yermolaev, O.

2012-04-01

388

NERI PROJECT 99-119. TASK 1. ADVANCED CONTROL TOOLS AND METHODS. FINAL REPORT  

SciTech Connect

Nuclear plants of the 21st century will employ higher levels of automation and fault tolerance to increase availability, reduce accident risk, and lower operating costs. Key developments in control algorithms, fault diagnostics, fault tolerance, and communication in a distributed system are needed to implement the fully automated plant. Equally challenging will be integrating developments in separate information and control fields into a cohesive system, which collectively achieves the overall goals of improved performance, safety, reliability, maintainability, and cost-effectiveness. Under the Nuclear Energy Research Initiative (NERI), the U. S. Department of Energy is sponsoring a project to address some of the technical issues involved in meeting the long-range goal of 21st century reactor control systems. This project, ''A New Paradigm for Automated Development Of Highly Reliable Control Architectures For Future Nuclear Plants,'' involves researchers from Oak Ridge National Laboratory, University of Tennessee, and North Carolina State University. This paper documents a research effort to develop methods for automated generation of control systems that can be traced directly to the design requirements. Our final goal is to allow the designer to specify only high-level requirements and stress factors that the control system must survive (e.g. a list of transients, or a requirement to withstand a single failure.) To this end, the ''control engine'' automatically selects and validates control algorithms and parameters that are optimized to the current state of the plant, and that have been tested under the prescribed stress factors. The control engine then automatically generates the control software from validated algorithms. Examples of stress factors that the control system must ''survive'' are: transient events (e.g., set-point changes, or expected occurrences such a load rejection,) and postulated component failures. These stress factors are specified by the designer and become a database of prescribed transients and component failures. The candidate control systems are tested, and their parameters optimized, for each of these stresses. Examples of high-level requirements are: response time less than xx seconds, or overshoot less than xx% ... etc. In mathematical terms, these types of requirements are defined as ''constraints,'' and there are standard mathematical methods to minimize an objective function subject to constraints. Since, in principle, any control design that satisfies all the above constraints is acceptable, the designer must also select an objective function that describes the ''goodness'' of the control design. Examples of objective functions are: minimize the number or amount of control motions, minimize an energy balance... etc.

March-Leuba, J.A.

2002-09-09

389

Philip Morris's Project Sunrise: weakening tobacco control by working with it  

PubMed Central

Objective To analyse the implications of Philip Morris USA's (PM's) overtures toward tobacco control and other public health organisations, 1995–2006. Data sources Internal PM documents made available through multi?state US attorneys general lawsuits and other cases, and newspaper sources. Methods Documents were retrieved from several industry documents websites and analysed using a case study approach. Results PM's Project Sunrise, initiated in 1995 and proposed to continue through 2006, was a long?term plan to address tobacco industry delegitimisation and ensure the social acceptability of smoking and of the company itself. Project Sunrise laid out an explicit divide?and?conquer strategy against the tobacco control movement, proposing the establishment of relationships with PM?identified “moderate” tobacco control individuals and organisations and the marginalisation of others. PM planned to use “carefully orchestrated efforts” to exploit existing differences of opinion within tobacco control, weakening its opponents by working with them. PM also planned to thwart tobacco industry delegitimisation by repositioning itself as “responsible”. We present evidence that these plans were implemented. Conclusion Sunrise exposes differences within the tobacco control movement that should be further discussed. The goal should not be consensus, but a better understanding of tensions within the movement. As the successes of the last 25 years embolden advocates to think beyond passage of the next clean indoor air policy or funding of the next cessation programme, movement philosophical differences may become more important. If tobacco control advocates are not ready to address them, Project Sunrise suggests that Philip Morris is ready to exploit them. PMID:16728753

McDaniel, P A; Smith, E A; Malone, R E

2006-01-01

390

Erosional Consequence of Saltcedar Control  

NASA Astrophysics Data System (ADS)

Removal of nonnative riparian trees is accelerating to conserve water and improve habitat for native species. Widespread control of dominant species, however, can lead to unintended erosion. Helicopter herbicide application in 2003 along a 12-km reach of the Rio Puerco, New Mexico, eliminated the target invasive species saltcedar ( Tamarix spp.), which dominated the floodplain, as well as the native species sandbar willow ( Salix exigua Nuttall), which occurred as a fringe along the channel. Herbicide application initiated a natural experiment testing the importance of riparian vegetation for bank stability along this data-rich river. A flood three years later eroded about 680,000 m3 of sediment, increasing mean channel width of the sprayed reach by 84%. Erosion upstream and downstream from the sprayed reach during this flood was inconsequential. Sand eroded from channel banks was transported an average of 5 km downstream and deposited on the floodplain and channel bed. Although vegetation was killed across the floodplain in the sprayed reach, erosion was almost entirely confined to the channel banks. The absence of dense, flexible woody stems on the banks reduced drag on the flow, leading to high shear stress at the toe of the banks, fluvial erosion, bank undercutting, and mass failure. The potential for increased erosion must be included in consideration of phreatophyte control projects.

Vincent, Kirk R.; Friedman, Jonathan M.; Griffin, Eleanor R.

2009-08-01

391

Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project: Fall 2006 Progress Update  

SciTech Connect

The U.S. Department of Energy (DOE) initiated the Controlled Hydrogen Fleet and Infrastructure Demonstration and Validation Project through a competitive solicitation process in 2003. The purpose of this project is to conduct an integrated field validation that simultaneously examines the performance of fuel cell vehicles and the supporting hydrogen infrastructure. Four industry teams have signed cooperative agreements with DOE and are supporting plans for more than 130 fuel cell vehicles and 20 hydrogen refueling stations over the 5-year project duration. This paper provides a status update covering the progress accomplished by the demonstration and validation project over the last six months; the first composite data products from the project were published in March 2006. The composite data products aggregate individual performance into a range that protects the intellectual property of the companies involved, while publicizing the progress the hydrogen and fuel cell industry is making as a whole relative to the program objectives and timeline. Updates to previously published composite data products, such as on-road fuel economy and vehicle/infrastructure safety, will be presented along with new composite data products, such as fuel cell stack efficiency and refueling behavior.

Wipke, K.; Welch, C.; Thomas, H.; Sprik, S.; Gronich, S.; Garbak, J.

2006-10-01

392

Insular Erosion, Isostasy, and Subsidence  

Microsoft Academic Search

Organic reefs and shore erosion record the intersection of sea level with islands. From this record it is possible to reconstruct the history of vertical movement of the islands and the adjacent deep sea floor, including midplate swells. As judged by coral thickness, islands with barrier reefs sink as though they were on thermally youthful crust regardless of the actual

H. W. Menard

1983-01-01

393

EROSION MECHANISM IN DUCTILE METALS  

SciTech Connect

The removal of material from the surface of a ductile metal by small impacting particles is a design concern to the builders of synthetic fuels plants that utilize pulverized coal to produce gaseous forms of fuel. A series of room temperature experiments was conducted to determine the mechanism of material removal when an erosive particle stream impacts on a ductile metal surface. 1100-0 and 7075-T6 aluminum were used for the target and 600 {micro}m SiC particles moving at a velocity of 100 fps in air for the eroding stream. It was determined that a combined forging-extrusion mechanism at produces small, highly distressed platelets of tarrget material that are knocked off the surfce by succeeding particle impacts is responsible for erosion at both low and high impingement angles. The larrge strains that produce the platelets occur in a thin surface region which is heated near or to the annealing temperature of the metal as a result of adiabatic shear deformation. This hard, sub-surface layer, once formed, increases the efficiency of platelet formation at the surface and the erosion rate increases to a constant level. This propos mechanism is a significant departure from previously believed micromachining mechanism of erosion of ductile metals.

Bellman Jr., Robert; Levy, Alan

1980-06-01

394

4, 21112142, 2007 Identifying erosive  

E-print Network

, soil moisture and vegetation cover along the year. These factors play a key role on soil erosion properties (soil erodi- bility in relation to freeze-thaw processes and soil moisture content) and current-thaw cycles, soil moisture content and soil erodibility (0.007 Mg h MJ-1 mm-1 ).15 This period includes

Boyer, Edmond

395

EROSION OF STRIP MINE LANDS  

EPA Science Inventory

The plot studies were carried out at Karthaus and Klingerstown to verify the accuracy of the erosion pin method of soil loss evaluation compared to soil loss measured in runoff samples. Subsequently, field studies at Kylertown and Kittaning were used to apply these methods. Kyler...

396

Sorbent injection into a slipstream baghouse for mercury control: Project summary  

Microsoft Academic Search

A project led by the Energy and Environmental Research Center to test and demonstrate sorbent injection as a cost-effective mercury control technology for utilities burning lignites has shown effective mercury capture under a range of operating conditions. Screening, parametric, and long-term tests were carried out at a slipstream facility representing an electrostatic precipitator–activated carbon injection–fabric filter configuration (called a TOXECON™

Jeffrey S. Thompson; John H. Pavlish; Lucinda L. Hamre; Melanie D. Jensen; David Smith; Steve Podwin; Lynn A. Brickett

2009-01-01

397

Application of the maximum entropy/optimal projection control design approach for large space structures  

NASA Technical Reports Server (NTRS)

The underlying philosophy and motivation of the optimal projection/maximum entropy (OP/ME) stochastic modelling and reduced order control design method for high order systems with parameter uncertainties are discussed. The OP/ME design equations for reduced-order dynamic compensation including the effect of parameter uncertainties are reviewed and the application of the methodology to several large space structure (LSS) problems of representative complexity is illustrated.

Hyland, D. C.

1985-01-01

398

Maximum Entropy/Optimal Projection (MEOP) control design synthesis: Optimal quantification of the major design tradeoffs  

NASA Technical Reports Server (NTRS)

The underlying philosophy and motivation of the optimal projection/maximum entropy (OP/ME) stochastic modeling and reduced control design methodology for high order systems with parameter uncertainties are discussed. The OP/ME design equations for reduced-order dynamic compensation including the effect of parameter uncertainties are reviewed. The application of the methodology to several Large Space Structures (LSS) problems of representative complexity is illustrated.

Hyland, D. C.; Bernstein, D. S.

1987-01-01

399

2008 Midwest Levee Failure: Erosion Studies  

E-print Network

/s ................................................................ 309? Fig. 251. PET depth vs. EFA erosion category ............................................................. 310 xxv Page Fig. 252. Grass seasonal zones.../s ................................................................ 309? Fig. 251. PET depth vs. EFA erosion category ............................................................. 310 xxv Page Fig. 252. Grass seasonal zones...

Bernhardt, Michelle Lee

2011-02-22

400

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Program review  

NASA Technical Reports Server (NTRS)

This report summarizes the Integrated Application of Active Controls (IAAC) Technology to an Advanced Subsonic Transport Project, established as one element of the NASA/Boeing Energy Efficient Transport Technology Program. The performance assessment showed that incorporating ACT into an airplane designed to fly approximately 200 passengers approximately 2,000 nmi could yield block fuel savings from 6 to 10 percent at the design range. The principal risks associated with incorporating these active control functions into a commercial airplane are those involved with the ACT system implementation. The Test and Evaluation phase of the IAAC Project focused on the design, fabrication, and test of a system that implemented pitch axis fly-by-wire, pitch axis augmentation, and wing load alleviation. The system was built to be flight worthy, and was planned to be experimentally flown on the 757. The system was installed in the Boeing Digital Avionics Flight Controls Laboratory (DAFCL), where open loop hardware and software tests, and a brief examination of a direct drive valve (DDV) actuation concept were accomplished. The IAAC Project has shown that ACT can be beneficially incorporated into a commercial transport airplane. Based on the results achieved during the testing phase, there appears to be no fundamental reason(s) that would preclude the commercial application of ACT, assuming an appropriate development effort is included.

1986-01-01

401

Erosion—diagnosis and risk factors  

Microsoft Academic Search

Dental erosion is a multifactorial condition: The interplay of chemical, biological and behavioural factors is crucial and\\u000a helps explain why some individuals exhibit more erosion than others. The erosive potential of erosive agents like acidic drinks\\u000a or foodstuffs depends on chemical factors, e.g. pH, titratable acidity, mineral content, clearance on tooth surface and on\\u000a its calcium-chelation properties. Biological factors such

A. Lussi; T. Jaeggi

2008-01-01

402

Gross erosion, net erosion and gross deposition of dust by wind: field data from  

E-print Network

Gross erosion, net erosion and gross deposition of dust by wind: field data from 17 desert surfaces, 3001 Heverlee, Belgium. Email: Dirk.Goossens@ees.kuleuven.be ABSTRACT: Wind erosion measurements were carried out in Nellis Dunes Recreation Area, southern Nevada, USA. Gross erosion (the total mass

Ahmad, Sajjad

403

Comparison of Inconel 625 and Inconel 600 in resistance to cavitation erosion and jet impingement erosion  

Microsoft Academic Search

Liquid droplet erosion (LDE), which often occurs in bellows made of nickel-based alloys, threatens the security operation of the nuclear power plant. As the candidate materials of the bellows, Inconel 600 and Inconel 625 were both tested for resistance to cavitation erosion (CE) and jet impingement erosion (JIE) through vibratory cavitation equipment and a jet apparatus for erosion-corrosion. Cumulative mass

H. X. Hu; Y. G. Zheng; C. P. Qin

2010-01-01

404

Histotripsy Erosion of Model Urinary Calculi  

PubMed Central

Abstract Background and Purpose Histotripsy is a pulsed focused ultrasound technology in which initiation and control of acoustic cavitation allow for precise mechanical fractionation of tissues. The present study examines the feasibility of using histotripsy for erosion of urinary calculi. Materials and Methods Histotripsy treatment was delivered from a 750-kHz transducer in the form of 5-cycle acoustic pulses at a 1-kHz pulse repetition frequency. Model stones were sonicated for 5 minutes at peak negative pressures (p-) of 10, 15, 19, 22, and 24-MPa. Resulting fragment sizes and comminution rates were assessed and compared with those achieved with a piezoelectric lithotripter (Wolf Piezolith 3000) operated at 2-Hz pulse repetition frequency and power level 17 (p-?=?14-MPa). Results Histotripsy eroded the surface of stones producing fine (<100??m) particulate debris in contrast to the progressive and incomplete subdivision of stones achieved with piezoelectric lithotripsy. The histotripsy erosion rate increased with increasing peak negative pressure from 10 to 19?MPa and then saturated, yielding an average rate of 87.9?±?12.8?mg/min at maximum treatment intensity. Piezoelectric lithotripsy achieved an average treatment rate of 110.7?±?27.4?mg/min. Conclusions Histotripsy comminution of urinary calculi is a surface erosion phenomenon that is mechanistically distinct from conventional shockwave lithotripsy (SWL), producing only fine debris as opposed to coarse fragments. These characteristics suggest that histotripsy offers a potential adjunct to traditional SWL procedures, and synergistic interplay of the two modalities may lead to possible increases in both rate and degree of stone fragmentation. PMID:21091223

Hall, Timothy L.; Maxwell, Adam D.; Xu, Zhen; Cain, Charles A.; Roberts, William W.

2011-01-01

405

Implantation and erosion of nitrogen in tungsten  

NASA Astrophysics Data System (ADS)

Nitrogen puffing is routinely applied in nuclear fusion plasma experiments with tungsten walls to control the amount of power emitted from the plasma by radiation. However, as nitrogen is retained in significant amounts in tungsten it adds some complexity to the plasma-wall interaction. Basic questions concerning the interaction of nitrogen with tungsten, namely the energy and temperature dependent retention of nitrogen implanted into tungsten and the erosion of the formed tungsten nitride by deuterium, are still open. To address these questions, laboratory experiments with a mass-filtered ion source and sample analysis with in situ x-ray photoelectron spectroscopy (XPS) and nuclear reaction analysis were performed. The results of the implantation and erosion measurements were interpreted by means of simulations with a Monte-Carlo code describing the interaction of energetic particles with matter in the binary collision approximation. This required the development of a forward calculation, converting the simulated depth profiles into XPS intensity ratios. With appropriate settings, the experimental implantation and erosion results at ambient temperature are well described by the simulations. However, for increased temperatures it has been observed that there is an unexpected difference between implanting nitrogen into tungsten before heating the sample and implantation into a heated sample. The application of the developed forward calculation is not limited to the problems presented in this work but can be applied especially to all kind of XPS sputter-depth profiling measurements. Finally, simulations with the previously validated Monte-Carlo code are used to extrapolate the presented results on nitrogen retention to energies and particle compositions relevant for fusion experiments. These simulations make quantitative predictions on nitrogen retention in tungsten and on relevant time scales. The simulations also show that recoil implantation of nitrogen by deuterium significantly increases the effective implantation depth of nitrogen.

Meisl, G.; Schmid, K.; Encke, O.; Höschen, T.; Gao, L.; Linsmeier, Ch

2014-09-01

406

Strength Matters: Resisting Erosion Across Upland Landscapes  

NASA Astrophysics Data System (ADS)

Soil-covered upland landscapes comprise a critical part of the habitable world and our understanding of their evolution as a function of different climatic, tectonic, and geologic regimes is important across a wide range of disciplines. Erosion laws, which help direct our study and drive our models of Earth surface processes are based on little field data. Soil production and transport play essential roles in controlling the spatial variation of soil depth and therefore hillslope hydrological processes, vegetation, and soil biological activity. Field-based confirmation of the hypothesized relationship between soil thickness and soil production is recent, however, and here we quantify the first direct physical explanation of variable soil production across landscapes. We report clear empirical linkages between the mechanical strength of the parent material (erodability), soil production rates determined from the same material, and the routing of water on hillslopes. Specifically, soil production rates determined from in situ produced 10Be and 26Al decrease exponentially with increasing shear strength of parent material across three very different field sites, all underlain by granitic bedrock: The Point Reyes Peninsular and The San Gabriel Mountains in California and the Nunnock River, Australia field site used for extensive previous work. At the same field sites, we use fallout radionuclide profiles to show how the flux of water across the soil-saprolite boundary changes significantly along the hillslope profile. Specifically, we quantify the transition from creep dominated bioturbation on the upper parts of the hillslopes to overland flow dominated surficial erosion towards the axis of the unchannelled swales. Our field-based data, collected across a full range of erosion and soil production rates and topographic settings, help explain more clearly the linkages between biota, weathering, hillslope hydrology, and the evolution of the Earth's surface.

Heimsath, A. M.

2012-12-01

407

Near-Bank Flow and Flood Induced Bank Erosion Processes Revealed by Application of Advanced Acoustic Techniques on a Mega-River  

NASA Astrophysics Data System (ADS)

Bank erosion processes are a key component of river morphodynamics, controlling rates of channel shift and ultimately governing floodplain system dynamics and sedimentology. Near-bank flow fields and the interactions of turbulent fluid flows in the near-bank zone with mechanisms of bank failure and erosion styles are presently poorly understood. Recent research has suggested that bank erosion and the type of failure mechanism can play an important role in protecting the bank toe from further erosion, notably through increased near-bank roughness and the resultant reduction in near-bank flow velocity and shear stress. An improved understanding of these interactive near-bank processes is essential if we are to improve our ability to predict bank erosion and channel morphodynamics. In this study we present a series of high-resolution multibeam sonar repeat near-bank surveys and acoustic Doppler profiles (acquired as part of the NERC funded STELAR-S2S project: www.stelar-s2s.org), from the monsoonal Mekong River in SE Asia. These data are the first to simultaneously capture detailed bank topography and near-bank flow processes of a mega-river during high flow conditions. Data is presented from a range of channel morphologies and includes a variety of geotechnical bank failure styles. The results show how systematic quantification of bank roughness over bank lengths of several channel widths can be used to quantify hydraulic roughness and how such information can be used to parameterise bank erosion models. Furthermore, the evolution and role of slumped material at the bank toe is also examined during the monsoonal flood. The methods, estimates of error and implications of the results for the morphodynamic function of large river systems will be discussed.

Leyland, J.; Parsons, D. R.; Darby, S. E.; Hackney, C. R.; Best, J.; Aalto, R. E.; Nicholas, A. P.

2013-12-01

408

Modeling fluvial erosion on regional to continental scales  

Microsoft Academic Search

The fluvial system is a major concern in modeling landform evolution in response to tectonic deformation. Three stream bed types (bedrock, coarse-bed alluvial, and fine-bed alluvial) differ in factors controlling their occurrence and evolution and in appropriate modeling approaches. Spatial and temporal transitions among bed types occur in response to changes in sediment characteristics and tectonic deformation. Erosion in bedrock

Alan D. Howard; William E. Dietrich; Michele A. Seidl

1994-01-01

409

THE ROLE OF SUBSURFACE WATER IN CONTRIBUTING TO STREAMBANK EROSION  

Microsoft Academic Search

Subsurface flow is known to contribute significantly to stream flow but its contribution to streambank failure, a process which may contribute significantly to sediment loading in streams, is not well known. Research is needed in understanding the contribution of concentrated, lateral subsurface flow to streambank failure and the hydraulic properties controlling seepage erosion. Laboratory experiments were conducted with two-dimensional soil

Garey A. Fox; Glenn V. Wilson; Raja Periketi; Bobby F. Cullum; Leili Gordji

410

Transient erosion rates predicted from topographic curvature of ridges (Feather River, California)  

NASA Astrophysics Data System (ADS)

Rates of erosion can control the morphology of entire landscapes. Methods to quantify erosion are expensive and time consuming, but potentially these rates may be predicted rapidly over large spatial extents using topographic metrics. In landscapes with similar vegetation, climate and geology, mean basin slope has been shown to be linearly correlated with erosion rate, except in rapidly eroding landscapes where hillslopes steepen to approach a threshold slope. However landscape evolution models in which hillslope sediment flux is non-linearly dependent on slopes predict the curvature of ridges to be linearly proportional to erosion rates (Roering et al 2007). The curvature of hilltops may respond to higher erosion rates than mean basin slope as ridge curvature is only limited by whether soil production can keep pace with channel erosion rates. We test the utility of ridge-top curvature for estimating erosion rates using high resolution (1m) Airborne Laser Swath Mapping (ALSM) derived digital elevation data. Cosmogenic radionuclide (CRN) derived erosion rates for our field site in the Feather River, California, suggests erosion rates vary over an order of magnitude (0.01 to >0.2cm yr-1) (Riebe et al 2000). These data, combined with new CRN-derived erosion rates, are used to demonstrate erosion scales linearly with hilltop curvature, where hillslopes are judged to have adjusted to the erosion rate in the channel at their toe. From this relationship we determine the diffusion coefficient which controls the relationship between hillslope gradient and sediment flux, allowing estimation of erosion rates throughout our field area. Previous workers have demonstrated that mean hillslope angle can stand as a proxy for erosion rates only at rates <~0.25mm yr-1, until threshold angles are reached (e.g. Binnie et al 2007). Using an algorithm to extract a network of ridgelines and sample the mean hilltop curvature for a series of drainage basins in the study area, we show that the curvature of ridges can potentially reflect much higher erosion rates. In addition, we demonstrate that ridge-top curvature can estimate transient erosion rates in the channel network in landscapes where the adjustment timescale of the hillslope is short compared to that of the channel.

Hurst, M. D.; Mudd, S. M.; Walcott, R.; Yoo, K.; Attal, M.

2010-12-01

411

Estimates of soil erosion using cesium-137 tracer models.  

PubMed

The soil erosion was studied by 137Cs technique in Yatagan basin in Western Turkey, where there exist intensive agricultural activities. This region is subject to serious soil loss problems and yet there is not any erosion data towards soil management and control guidelines. During the soil survey studies, the soil profiles were examined carefully to select the reference points. The soil samples were collected from the slope facets in three different study areas (Kirtas, Peynirli and Kayisalan Hills). Three different models were applied for erosion rate calculations in undisturbed and cultivated sites. The profile distribution model (PDM) was used for undisturbed soils, while proportional model (PM) and simplified mass balance model (SMBM) were used for cultivated soils. The mean annual erosion rates found using PDM in undisturbed soils were 15 t ha(-1) year(-1) at the Peynirli Hill and 27 t ha(-1) year(-1) at the Kirtas Hill. With the PM and SMBM in cultivated soils at Kayi?alan, the mean annual erosion rates were obtained to be 65 and 116 t ha(-1) year(-1), respectively. The results of 137Cs technique were compared with the results of the Universal Soil Loss Equation (USLE). PMID:17690991

Saç, M M; U?ur, A; Yener, G; Ozden, B

2008-01-01

412

Sandstone landforms shaped by negative feedback between stress and erosion  

NASA Astrophysics Data System (ADS)

Weathering and erosion of sandstone produces unique landforms such as arches, alcoves, pedestal rocks and pillars. Gravity-induced stresses have been assumed to not play a role in landform preservation and to instead increase weathering rates. Here we show that increased stress within a landform as a result of vertical loading reduces weathering and erosion rates, using laboratory experiments and numerical modelling. We find that when a cube of locked sand exposed to weathering and erosion processes is experimentally subjected to a sufficiently low vertical stress, the vertical sides of the cube progressively disintegrate into individual grains. As the cross-sectional area under the loading decreases, the vertical stress increases until a critical value is reached. At this threshold, fabric interlocking of sand grains causes the granular sediment to behave like a strong, rock-like material, and the remaining load-bearing pillar or pedestal landform is resistant to further erosion. Our experiments are able to reproduce other natural shapes including arches, alcoves and multiple pillars when planar discontinuities, such as bedding planes or fractures, are present. Numerical modelling demonstrates that the stress field is modified by discontinuities to make a variety of shapes stable under fabric interlocking, owing to the negative feedback between stress and erosion. We conclude that the stress field is the primary control of the shape evolution of sandstone landforms.

Bruthans, Jiri; Soukup, Jan; Vaculikova, Jana; Filippi, Michal; Schweigstillova, Jana; Mayo, Alan L.; Masin, David; Kletetschka, Gunther; Rihosek, Jaroslav

2014-08-01

413

Advanced emissions control development project. Final report, November 1, 1993--February 29, 1996. Phase I  

SciTech Connect

The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of air toxics from coal-fired boilers. Ideally, the project aim is to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPs), fabric filters (baghouses), and wet flue gas desulfurization. B&W`s Clean Environment Development Facility (CEDF) and the AECDP equipment combined to form a state-of-the-art facility for integrated evaluation of combustion and post-combustion emissions control options. Phase I activities were primarily directed at providing a reliable, representative test facility for conducting air toxic emission control development work later in the project. This report summarizes the AECDP Phase I activities which consisted of the design, installation, shakedown, verification, and air toxics benchmarking of the AECDP facility. The AECDP facility consists of an ESP, pulse-jet baghouse, and wet scrubber. All verification and air toxic tests were conducted with a high sulfur, bituminous Ohio coal. In order to successfully apply the results of the program to utility systems, the relationship between the performance of the CEDF/AECDP test equipment and commercial units had to be established. The first step in the verification process was to validate that the flue gas treatment devices - boiler/convection pass simulator, ESP, baghouse, and wet SO{sub 2} scrubber - operate in a manner representative of commercial units.

Farthing, G.A.

1996-02-29