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1

Controlled ultrasonic tissue erosion  

NASA Astrophysics Data System (ADS)

Controlled ultrasonic tissue erosion has many clinical applications, including the placement of very precise sharply defined perforations in biological interfaces and membranes with focused ultrasound. With carefully chosen acoustic parameters, tissue can be rapidly eroded away at a constant etching rate. The maximum erosion rate for minimal propagated energy is obtained by using very short high intensity pulses. The etching rate is higher with shorter pulse durations. For short pulses less than 10 cycles of the drive frequency, an optimum pulse repetition rate exists which maximizes the etching rate. Higher gas saturation in the surrounding medium reduces the etching rate and reduces the spatial sharpness of the holes produced. Most of the erosion appears to be produced in the first several cycles of the therapy pulse. For example, a series of short (about 3 cycles) focused pulses of 2100 W/cm2 (Isppa) at 788 kHz can erode a very well defined 2 mm diameter hole in a 1 mm thick sample of fresh pork atrial posterior wall in about 1 min at the optimum pulse repetition rate (about 18 kHz). Controlled ultrasonic tissue erosion may provide an effective image guided noninvasive tool in treatment of neonatal patients with hypoplastic left heart syndrome. Without the mixing of oxygenated blood across perforations placed in the atrial septum, these infants do not survive.

Cain, Charles

2003-04-01

2

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

3

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

4

Ecological Monitoring of Beach Erosion Control Projects, Broward County, Florida, and Adjacent Areas.  

National Technical Information Service (NTIS)

Ecological monitoring of algae, invertebrates, and fishes was conducted in the southeast Florida coast in connection with offshore dredging and beach nourishment projects. The Pompano Beach to Lauderdale-by-the-Sea segment of the Broward County Beach Eros...

D. J. Harrema J. van Montfrans M. J. Thompson W. P. Azzinaro W. R. Courtenay

1974-01-01

5

78 FR 34374 - Notice of Availability of Final Revisions to the Upland Erosion Control, Revegetation, and...  

Federal Register 2010, 2011, 2012, 2013

...Availability of Final Revisions to the Upland Erosion Control, Revegetation, and Maintenance...Energy Projects has revised its Upland Erosion Control, Revegetation, and Maintenance...baseline mitigation measures for minimizing erosion, enhancing revegetation, and...

2013-06-07

6

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.

7

Sediment and Erosion Control: An Inventory of Current Practices.  

National Technical Information Service (NTIS)

The report was prepared to inventory sediment and erosion control practices currently in use nationwide. The inventory represents completion of the first of a six task project designed to develop guidance, including model permit language, for development ...

M. Mitchell

1990-01-01

8

Wire Mesh Reinforced Erosion Control Mat.  

National Technical Information Service (NTIS)

This study involved evaluating the constructability and performance of the wire mesh reinforced erosion control mat, installed on SR 00724-03M, in Berks County. The purpose of this MacMat-R8 was to address a persistent erosion control condition. These thr...

D. L. LePage R. A. Vanscavish

1999-01-01

9

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.

10

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

11

Turf Establishment and Erosion Control.  

National Technical Information Service (NTIS)

Accelerated soil erosion and the sedimentation caused by it pose serious problems for the construction industry and state and local agencies. Runoff from construction sites has high sediment loads which may contain various pollutants, including oil, chemi...

A. M. Johnson

1992-01-01

12

Urban Soil Erosion and Sediment Control.  

National Technical Information Service (NTIS)

The study was conducted to determine the causes and the extent of urban and suburban soil erosion and sediment problems, and to describe ways in which local communities can organize and implement effective sedimentation control programs. An evaluation is ...

M. D. Powell W. C. Winter W. P. Bodwitch

1970-01-01

13

Rainfall Controls Cascade Mountains' Erosion and Bedrock Uplift Patterns  

NSF Publications Database

... nsf.gov Rainfall Controls Cascade Mountains' Erosion and Bedrock Uplift Patterns Arlington, Va ... University. "Geologists usually think of erosion wearing away mountains," says David Fountain ...

14

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

15

Virginia Erosion and Sediment Control Handbook. Standards, Criteria and Guidelines.  

ERIC Educational Resources Information Center

Guidelines and technical standards for development of local erosion and sediment control programs and conservation standards to meet the goals established by the Virginia Erosion and Sediment Control law are presented in this handbook. Part I defines natural and manmade erosion, sedimentation, and the hazards of uncontrolled wear and damage to the…

Virginia State Soil and Water Conservation Commission, Richmond, VA.

16

The control of erosion-corrosion in slurry pipelines  

Microsoft Academic Search

The results of erosion-corrosion testing in pilot plant slurry pipelines are related to the behaviour of operating slurry pipelines and the control of erosion-corrosion in such systems by use of inhibitors, solution conditioning and adjustment of slurry parameters. The erosion-corrosion component of the total wear is oxygen-mass-transfer controlled and the magnitude of the erosion-corrosion can be estimated using well established

Postlethwaite

1987-01-01

17

Estimation of sediment-discharge reduction for two sites of the Yazoo River basin demonstration erosion control project, north-central Mississippi, 1985-94  

USGS Publications Warehouse

Sediment-discharge reduction was estimated at two Demonstration Erosion Control sites in north-central Mississippi for the period 1985 through 1994. Decreasing trends were detected in flow-adjusted sediment discharge at Hotopha Creek near Batesville for the study period. The annual reduction in sediment discharge at this site was about 7 percent (0.68 ton per day per year). Decreasing trends were also detected in flow- adjusted sediment discharge at Otoucalofa Creek Canal near Water Valley for the study period. The annual reduction in sediment discharge at this site was about 11 percent (5.33 tons per day per year). The computations used to estimate sediment-discharge reduction were based on time series of instantaneous sediment discharges for the study period. Non-parametric procedures were used to compute trends in sediment discharge and to quantify reductions over time at the two sites. Parametric procedures were then used to verify the non-parametric results.

Rebich, R. A.

1995-01-01

18

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

19

Weld overlay coatings for erosion control  

Microsoft Academic Search

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

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

1993-01-01

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

Gully erosion: Impacts, factors and control  

Microsoft Academic Search

Gully erosion attracts increasing attention from scientists as reflected by two recent international meetings [Poesen and Valentin (Eds.), Catena 50 (2–4), 87–564; Li et al., 2004. Gully Erosion Under Global Change. Sichuan Science Technology Press, Chengu, China, 354 pp.]. This growing interest is associated with the increasing concern over off-site impacts caused by soil erosion at larger spatial scales than

C. Valentin; J. Poesen; Yong Li

2005-01-01

22

The control of erosion-corrosion in slurry pipelines  

SciTech Connect

The results of erosion-corrosion testing in pilot plant slurry pipelines are related to the behaviour of operating slurry pipelines and the control of erosion-corrosion in such systems by use of inhibitors, solution conditioning and adjustment of slurry parameters. The erosion-corrosion component of the total wear is oxygen-mass-transfer controlled and the magnitude of the erosion-corrosion can be estimated using well established mass transfer correlations. There is a breakaway velocity for each slurry below which mechanical erosion of the pipe is not a problem and it is suggested that slurry pipelines may be operated below this velocity but under conditions of particle size and velocity where the pipe wall is kept free from rust and scale to prevent pitting corrosion. The erosion-corrosion would be controlled by inhibitors and/or dearation resulting in a smooth rust and scale free pipe.

Postlethwaite, J.

1987-01-01

23

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

24

Reduction in interrill sediment transport by rolled erosion control systems  

Microsoft Academic Search

Rolled erosion control systems (RECS) reduce detachment and transport of sediment by mitigating the basic processes of run-off and erosion (e.g., splash detachment, interrill transport, run-off velocity, surface crusting). Despite the variety of products available in the market today, only limited research has been conducted on their influence on erosion subprocesses. This study addresses some of the limitations of previous

A. D. Ziegler; R. A. Sutherland

1998-01-01

25

Cloud forest restoration for erosion control in a Kichwa community of the Ecuadorian central Andes Mountains  

NASA Astrophysics Data System (ADS)

The Denver Professional Chapter of Engineers Without Borders (EWB) has begun conducting erosion control projects in the Kichwa communities of Malingua Pamba in the Andes Mountains south of Quito, Ecuador. In many high elevation areas in this region, erosion of volcanic soils on steep hillsides (i.e., < 40%) is severe and often associated with roads, water supply systems, and loss of native cloud forests followed by burning and cultivation of food crops. Following a 2011 investigation of over 75 erosion sites, the multidisciplinary Erosion Control team traveled to Malingua Pamba in October 2012 to conduct final design and project implementation at 5 sites. In partnership with the local communities, we installed woody cloud forest species, grass (sig-sig) contour hedges, erosion matting, and rock structures (toe walls, plunge pools, bank armoring, cross vanes, contour infiltration ditches, etc.) to reduce incision rates and risk of slump failures, facilitate aggradation, and hasten revegetation. In keeping with the EWB goal of project sustainability, we used primarily locally available resources. High school students of the community grew 5000 native trees and some naturalized shrubs in a nursery started by the school principal, hand weavers produced jute erosion mats, and rocks were provided by a nearby quarry. Where possible, local rock was harvested from landslide areas and other local erosion features. Based on follow up reports and photographs from the community and EWB travelers, the approach of using locally available materials installed by the community is successful; plants are growing well and erosion control structures have remained in place throughout the November to April rainy season. The community has continued planting native vegetation at several additional erosion sites. Formal monitoring will be conducted in October 2013, followed by analysis of data to determine if induced meandering and other low-maintenance erosion control techniques are working as planned. For comparison of techniques, we will consider installing check dams in comparable gullies. The October 2013 project will also focus on training the community how to conduct erosion control site assessments, design site-appropriate structures, and implement erosion control and revegetation plans. Following the training, the community will teach these skills to adjacent villages.

Backus, L.; Giordanengo, J.; Sacatoro, I.

2013-12-01

26

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

Federal Register 2010, 2011, 2012, 2013

...No. AD12-2-000] Notice of Intent To Update the Upland Erosion Control and Revegetation and Maintenance Plan and the Wetland...of Energy Projects is in the process of reviewing its Upland Erosion Control, Revegetation and Maintenance Plan (Plan) and...

2011-11-07

27

18 CFR 1304.202 - General sediment and erosion control provisions.  

Code of Federal Regulations, 2013 CFR

...General sediment and erosion control provisions. 1304.202...ALTERATIONS TVA-Owned Residential Access Shoreland § 1304.202 General sediment and erosion control provisions. (a) During...appropriate erosion and sediment control measures be utilized to...

2014-04-01

28

48 CFR 452.236-74 - Control of Erosion, Sedimentation, and Pollution.  

Code of Federal Regulations, 2013 CFR

...Control of Erosion, Sedimentation, and Pollution. 452.236-74 Section 452.236-74...Control of Erosion, Sedimentation, and Pollution. As prescribed in 436.574, insert...Control of Erosion, Sedimentation, and Pollution (NOV 1996) (a) Operations...

2013-10-01

29

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

Code of Federal Regulations, 2013 CFR

...Control of erosion, sedimentation, and pollution. 436.574 Section 436.574 ...Control of erosion, sedimentation, and pollution. The contracting officer shall insert...Control of Erosion, Sedimentation and Pollution, if there is a need for applying...

2013-10-01

30

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...

31

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

32

Live Stake and Joint Planting for Streambank Erosion Control.  

National Technical Information Service (NTIS)

The live stake (LS) and joint planting (JP) soil bioengineering systems are units fabricated from live, woody plant material branches. Over time, the LS's are effective for erosion control and the JP system provides reinforcement to slopes upon which rock...

J. C. Fischenich R. B. Sotir

2007-01-01

33

Performance of Flexible Erosion Control Materials.  

National Technical Information Service (NTIS)

The objectives of the study were to determine the effect of flexible materials on the germination and growth of native grasses, as well as to determine the effectiveness of the materials to prevent erosion on typical, steep, roadside slopes before the est...

H. C. Landphair J. A. McFalls J. P. Long S. H. Godfrey

1993-01-01

34

Controlling Erosion and Sediment Loss from Furrow-Irrigated Cropland  

Microsoft Academic Search

Irrigation-induced erosion and subsequent sediment loss is a serious agricultural and environmental problem. Recent recognition of this problem has stimulated the development and evaluation of erosion and sediment-loss-control technology. Research results indicate that the application of the technology avail- able today can reduce sediment loss by 70-100%. Important practices include irrigation-water management, sediment-retention basins, buried-pipe tailwater-control systems, vegetative filter strips,

D. L. Carter; C. E. Brockway; K. K. Tanji

1993-01-01

35

Using a Stream Table to Investigate Erosion Control  

NSDL National Science Digital Library

This activity will introduce students to water-induced topsoil erosion and different ways to control it. Using a stream table (prepared by the teacher), they will vary the surface of the 'soil', and the height of the table, pour in water, and observe sheet, rill, and gully erosion. They can also investigate the effects of check dams (by plugging gullies with pebbles), observe the results of contour plowing, and test the effectiveness of different types of mulch (straw, shredded paper, pine needles, etc.) in preventing erosion. Instructions for constructing a stream table, a student worksheet, and discussion questions are provided.

36

Index Testing to Support the Stormwater Management Erosion and Sediment Control Laboratory.  

National Technical Information Service (NTIS)

The main aim of the project was to support the Stormwater Management Academy Research and Testing Laboratory (SMARTL) with material index testing. In addition to testing erosion and sediment control products on the test beds in the field-scale laboratory ...

I. Gogo-Abite M. Chopra M. Hardin M. Wanielista

2010-01-01

37

Erosion  

NSDL National Science Digital Library

Relate the building up and breaking down of the Earth\\'s surface over time to the various physical land features. Some of the amazing land forms we see in the world are formed by erosion. A lot of these land forms are found in the United States. Can you think of a few landforms you have heard of in the United States? Write a few of them ...

Wstewart

2007-10-08

38

THE ROLE OF ENVIRONMENTAL EDUCATION IN PREDICTING ADOPTION OF WIND EROSION CONTROL PRACTICES  

Microsoft Academic Search

Logit and ordered probit analyses were used to identify factors associated with reduced tillage adoption, continuous spring cropping, and the number of changes made in response to wind erosion. Contrary to previous results for water erosion control, simple perception of a wind erosion problem or membership in a particular socioeconomic category did not significantly explain adoption of wind erosion control

H. Holly Wang; Douglas L. Young; Oumou M. Camara

2000-01-01

39

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

40

Tybee Island, Georgia, Beach Erosion Control Project.  

National Technical Information Service (NTIS)

The proposal concerns restoration and periodic nourishment of 13,200 feet of ocean beach and a rubble stone terminal groin extending 800 feet seaward. Proposed for the future, when and if needed, is the placement of two additional rubble groins 760 feet a...

1973-01-01

41

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

42

A Comparison of Erosion and Water Pollution Control Strategies for an Agricultural Watershed  

Microsoft Academic Search

The effectiveness and efficiency of two erosion control strategies and one water pollution control (riparian) strategy are compared for Idaho's Tom Beall watershed. Erosion control strategies maximize annualized net returns per hectare on each field and restrict field erosion rates to no more than 11.2 or 16.8 tons per hectare. The riparian strategy uses good vegetative cover on all fields

Tony Prato; Hongqi Shi

1990-01-01

43

A comparison of erosion and water pollution control strategies for an agricultural watershed  

Microsoft Academic Search

The effectiveness and efficiency of two erosion control strategies and one water pollution control (riparian) strategy are compared for Idaho's Tom Beall watershed. Erosion control strategies maximize annualized net returns per hectare on each field and restrict field erosion rates to no more than 11.2 or 16.8 tons per hectare. The riparian strategy uses good vegetative cover on all fields

Tony Prato; Hongqi Shi

1990-01-01

44

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

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Control of erosion, sedimentation, and pollution. 436.574 Section... 436.574 Control of erosion, sedimentation, and pollution. The contracting...452.236-74, Control of Erosion, Sedimentation and Pollution, if there is a need...

2009-10-01

45

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

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Control of erosion, sedimentation, and pollution. 436.574 Section... 436.574 Control of erosion, sedimentation, and pollution. The contracting...452.236-74, Control of Erosion, Sedimentation and Pollution, if there is a need...

2010-10-01

46

Impacts of Grain for Green Project on Soil Erosion in China  

NASA Astrophysics Data System (ADS)

Since 1999 the Grain for Green Project (GGP) has been considered as one of the most important projects for ecological restoration of China. This paper quantitatively analyzed the impacts of the GGP on soil erosion in study area. GGP is aimed to change land use on slope land. The government is carrying out subside policy to encourage farmer converse cropping to plant tree or grass on the slope land. According to the observation data of 11 rivers of China, the runoff and soil erosion significantly decreased. Compared with 1998-2002 the runoff and sediment yield in 2003-2007 were decreased by 18% and 45.4% respectively. In order to evaluate the impacts of GGP on soil erosion in detail, the Yan River Basin of Loess Plateau was taken as an example. Keywords: The China's Grain for Green Project, soil erosion, ecological restoration

Li, R.; Wang, F.; Xie, H.

2012-04-01

47

The State of the Art of Erosion and Sediment Control for Surface Mined Areas.  

National Technical Information Service (NTIS)

This thesis attempts to define the state of the art of sediment and erosion control for surface mined areas with emphasis on sediment ponds. Additionally, pertinent hydrologic aspects, sediment characteristics, and the erosion processes are briefly review...

J. L. Gilbreath

1979-01-01

48

Modeling of technical soil-erosion control measures and its impact on soil erosion off-site effects within urban areas  

NASA Astrophysics Data System (ADS)

The paper presents results of surface runoff, soil erosion and sediment transport modeling using Erosion 3D software - physically based mathematical simulation model, event oriented, fully distributed. Various methods to simulate technical soil-erosion conservation measures were tested, using alternative digital elevation models of different precision and resolution. Ditches and baulks were simulated by three different approaches, (i) by change of the land-cover parameters to increase infiltration and decrease flow velocity, (ii) by change of the land-cover parameters to completely infiltrate the surface runoff and (iii) by adjusting the height of the digital elevation model by "burning in" the channels of the ditches. Results show advantages and disadvantages of each approach and conclude suitable methods for combinations of particular digital elevation model and purpose of the simulations. Further on a set of simulations was carried out to model situations before and after technical soil-erosion conservation measures application within a small catchment of 4 km2. These simulations were focused on quantitative and qualitative assessment of technical soil-erosion control measures impact on soil erosion off-site effects within urban areas located downstream of intensively used agricultural fields. The scenarios were built upon a raster digital elevation model with spatial resolution of 3 meters derived from LiDAR 5G vector point elevation data. Use of this high-resolution elevation model allowed simulating the technical soil-erosion control measures by direct terrain elevation adjustment. Also the structures within the settlements were emulated by direct change in the elevation of the terrain model. The buildings were lifted up to simulate complicated flow behavior of the surface runoff within urban areas, using approach of Arévalo (Arévalo, 2011) but focusing on the use of commonly available data without extensive detailed editing. Application of the technical soil-erosion control measures induced strong change in overall amount of eroded/deposited material as well as spatial erosion/deposition patterns within the settlement areas. Validation of modeled scenarios and effects on measured data was not possible as no real runoff event was recorded in the target area so the conclusions were made by comparing the different modeled scenarios. Advantages and disadvantages of used approach to simulate technical soil-erosion conservation measures are evaluated and discussed as well as the impact of use of high-resolution elevation data on the intensity and spatial distribution of soil erosion and deposition. Model approved ability to show detailed distribution of damages over target urban area, which is very sensitive for off-site effects of surface runoff, soil erosion and sediment transport and also high sensitivity to input data, especially to DEM, which affects surface runoff pattern and therefore intensity of harmful effects. Acknowledgement: This paper has been supported by projects: Ministry of the interior of the CR VG 20122015092, and project NAZV QI91C008 TPEO.

Dostal, Tomas; Devaty, Jan

2013-04-01

49

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

50

Wetland Platform Erosion by Wave Action and its Implications for Future Mitigation Projects in South Louisiana  

NASA Astrophysics Data System (ADS)

The transition of marshland to open water in south Louisiana continues at an alarming rate, and freshwater diversions and marsh restoration projects have been implemented or are planned to address this loss. This project examines the magnitude and impact of wave-induced subaqueous platform erosion that occurs during and following subsidence of the subaerial marsh. Study and control sites have been chosen in Breton Sound, where an existing freshwater diversion project (Caernarvon) has been operational since 1991; Barataria Bay, where the Davis Pond diversion has been active since 2003; and the Deltas National Wildlife Refuge (DNWR), where marshes are still receiving significant freshwater and sediment from the Mississippi River. Study grids are established along marsh fringes in bay-fronting, gulf-fronting, and interior ponds that have a variety of orientations and open water fetch to predominant wave attack and in recent years (since the 1930s) have shown significant wetland loss. Subaqueous platform elevation and stratigraphy are examined with vibracores and transit elevation transects and detailed bathymetric maps of the 1 km grids are also made with an Odom Hydrotrak HT100 fathometer. Preliminary results suggest that the overall magnitude of wave-induced erosion is extreme (deflation of 1-1.5 m) in Barataria Bay sites, but may not be as great a magnitude in Breton Sound or the DNWR sites. Shoreline orientation to wave attack, the composition and resistance to wave re-working of the underlying sediment, or the presence of submerged aquatic vegetation (SAV) that serves to stabilize the substrata may help explain the resultant site to site variability. Predominant in many sites, once the aerial marsh has submerged, a portion of the peat deposits is preserved below more recent onlapping bay bottom sediments.

Wilson, C.; Allison, M.

2004-12-01

51

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

52

Control of fan erosion in coal-fired power plants, Phase 2: Final report  

SciTech Connect

The Electric Power Research Institute contracted with Westinghouse to address the problems electric utilities experience caused by fan erosion. The objective of this phase of the research program was to understand how to control erosion damage to coal-fired power plant fans by: Developing fan design modifications that raise the tolerance of fans to fly-ash erosion and that simultaneously improve fan performance. Understanding why fly ashes vary in their erosivities and developing the ability to predict the erosivity of the fly ash from core borings of the fuel to be fired; Evaluating the performance of erosion protection systems we have installed on a number of fans suffering severe fly-ash erosion damage; Developing a method to armor centrifugal fans against fly-ash erosion while providing for easy field replacement of the blade liners; and Developing a computer model that calculates particle trajectories through the inlet box of a fan. 18 refs., 74 figs., 18 tabs.

Sverdrup, E.F.; Albertin, L.; Chamberlin, R.M.; D'Amico, N.J.; El Masri, M.A.; Glasser, A.D.; Menguturk, M.; Rane, A.; Racki, R.; Petlevich, W.J.

1988-11-01

53

Water erosion assessment and control in Northern Iraq  

Microsoft Academic Search

The semiarid region of northern Iraq consists of about 12 millions ha of forest, grazing and farmland areas. Water erosion is a serious problem on forest and grazing lands due mainly to land mismanagement. On cropland, conventional farming practices and intensive cropping increased water erosion on marginal land. To assess the damage caused by water erosion in the region, the

Mohammad H. Hussein

1998-01-01

54

A Comparison of Erosion and Water Pollution Control Strategies for an Agricultural Watershed  

NASA Astrophysics Data System (ADS)

The effectiveness and efficiency of two erosion control strategies and one water pollution control (riparian) strategy are compared for Idaho's Tom Beall watershed. Erosion control strategies maximize annualized net returns per hectare on each field and restrict field erosion rates to no more than 11.2 or 16.8 tons per hectare. The riparian strategy uses good vegetative cover on all fields adjacent to the creek and in noncropland areas and the resource management system that maximizes annualized net returns per hectare on remaining fields. The Agricultural Nonpoint Source Pollution model is used to simulate the levels and concentrations of sediment, nitrogen, phosphorus, and chemical oxygen demand at the outlet of the watershed. Erosion control strategies generate less total erosion and water pollution but are less efficient than the riparian strategy. The riparian strategy is less equitable for farmers than the erosion control strategies.

Prato, Tony; Shi, Hongqi

1990-02-01

55

Projected-Fringe Profilometer Maps Erosion Of Electrode  

NASA Technical Reports Server (NTRS)

Report describes use of projected-fringe, phase-stepping optical profilometer to measure three-dimensional shape of surface of molybdenum electrode eroded in ion engine. Instrumentation used in these measurements similar to that described in "Projected-Fringe, Phase-Stepping Profilometer" (LEW-14996).

Macrae, Gregory S.; Mercer, Carolyn R.

1995-01-01

56

Current projects in Fuzzy Control  

NASA Technical Reports Server (NTRS)

Viewgraphs on current projects in fuzzy control are presented. Three projects on helicopter flight control are discussed. The projects are (1) radio control by oral instructions; (2) automatic autorotation entry in engine failure; and (3) unmanned helicopter for sea rescue.

Sugeno, Michio

1990-01-01

57

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

58

Beach erosion control study at Pass Christian. [using remote sensors and satellite observation  

NASA Technical Reports Server (NTRS)

The methods of measuring the existence of erosion and the effects of sand stabilization control systems are described. The mechanics of sand movement, the nature of sand erosion, and the use of satellite data to measure these factors and their surrogates are discussed using the locational and control aspects of aeolian and litoral erosion zones along the sand beach of the Mississippi coast. The aeolian erosion is highlighted due to the redeposition of the sand which causes high cleanup costs, property damage, and safety and health hazards. The areas of differential erosion and the patterns of beach sand movement are illustrated and the use of remote sensing methods to identify the areas of erosion are evaluated.

1978-01-01

59

Device Oriented Project Controller  

SciTech Connect

This proposal is directed at the issue of developing control systems for very large HEP projects. A de-facto standard in accelerator control is the Experimental Physics and Industrial Control System (EPICS), which has been applied successfully to many physics projects. EPICS is a channel based system that requires that each channel of each device be configured and controlled. In Phase I, the feasibility of a device oriented extension to the distributed channel database was demonstrated by prototyping a device aware version of an EPICS I/O controller that functions with the current version of the channel access communication protocol. Extensions have been made to the grammar to define the database. Only a multi-stage position controller with limit switches was developed in the demonstration, but the grammar should support a full range of functional record types. In phase II, a full set of record types will be developed to support all existing record types, a set of process control functions for closed loop control, and support for experimental beam line control. A tool to configure these records will be developed. A communication protocol will be developed or extensions will be made to Channel Access to support introspection of components of a device. Performance bench marks will be made on both communication protocol and the database. After these records and performance tests are under way, a second of the grammar will be undertaken.

Dalesio, Leo; Kraimer, Martin

2013-11-20

60

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

61

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

62

Control and evaluation of particle impact conditions in a sand erosion test facility  

Microsoft Academic Search

For the prediction of actual damage to plant component materials and for making the erosion mechanisms clear, it is important to control and to evaluate the particle impact conditions in a testing facility. A sand blast type erosion test rig, which can achieve the particle impact velocities up to 135ms?1 and a wide range of impact angles has been constructed.

Y. I Oka; M Nishimura; K Nagahashi; M Matsumura

2001-01-01

63

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

64

Nozzle passage aerodynamic design to reduce solid particle erosion of a supercritical steam turbine control stage  

Microsoft Academic Search

The solid particle erosion on the control stage nozzle of supercritical steam turbines can be reduced by using suitable nozzle passage design to control the particle impacting velocity and impacting angle. In this paper, two nozzle designs with tip endwall contouring\\/an aft-loaded vane profile respectively are presented. Furthermore, anti-erosion performances of these two nozzles for a supercritical steam turbine control

Liping Dai; Maozheng Yu; Yiping Dai

2007-01-01

65

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

66

Physicochemical Aspects of Gun Barrel Erosion and Its Control.  

National Technical Information Service (NTIS)

Gun tube erosion can be defined as the bore surface damage and bore enlargement caused by firing, which can lead to loss in accuracy and the effectiveness of the weapon. It is one of the two major factors on the basis of which gun tubes are condemned; the...

I. Ahmad

1972-01-01

67

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.

68

Shoreline erosion control using marsh vegetation and low-cost structures  

SciTech Connect

Erosion is a serious threat to waterfront property along most of North Carolina's extensive estuarine shoreline. It is accelerated by man's intensive use and mismanagement. As demand for shoreline property increases -- for homesites, recreational areas, marinas and industrial sites -- its value increases, and landowners become more concerned about loss of land to erosion. There is a variety of erosion-control methods -- some beneficial, some useless and others that are even detrimental. Structural methods such as bulkheads, groins, revetments and riprap are often effective. But they are expensive to build and maintain and may have adverse environmental effects. Establishing vegetation is much cheaper than structural methods of erosion control, and the new marsh provides habitat, food and nutrients for organisms in the surrounding estuarine waters.

Broome, S.W.; Rogers, S.M.; Seneca, E.D.; Burgess, C.B.

1992-01-01

69

Post-Fire Erosion Control Research on the San Dimas Experimental Forest: Past and Present  

Microsoft Academic Search

The San Dimas Experimental Forest (SDEF) was established in the early 1930s to document and quantify wildland hydrology in the semiarid chaparral-covered steeplands of southern California. Concomitantly, the nearly seventy years of accumulated watershed research in this fire-prone ecosystem has produced invaluable information on post-fire erosion and the effectiveness and consequences of post-fire erosion control treatments. On average, first-year post-fire

Peter M. Wohlgemuth

70

Wind tunnel experimental study on the effect of PAM on soil wind erosion control.  

PubMed

In recent years, high-molecular-weight anionic polyacrylamide (PAM) have been widely tested on a variety of soils, primarily in water erosion control. However, little information is available regarding the effectiveness of PAM on preventing soil loss from wind erosion. The research adopted room wind tunnel experiment, two kinds of soils were used which were from the agro-pastoral area of Inner Mongolia, the northwest of China, the clay content of soils were 22.0 and 13.7%, respectively. For these tests, all the treatments were performed under the condition of wind velocity of 14 m s(-1) and a blown angle of 8.75%, according to the actual situation of experimented area. The study results indicated that using PAM on the soil surface could enhance the capability of avoiding the wind erosion, at the same time, the effect of controlling wind soil erosion with 4 g m(-2) PAM was better than 2 g m(-2) PAM's. Economically, the 2 g m(-2) PAM used in soil surface can control wind erosion effectively in this region. The prophase PAM accumulated in soil could not improve the capability of avoiding the wind erosion, owing to the degradation of PAM in the soil and the continual tillage year after year. The texture of soil is a main factor influencing the capability of soil avoiding wind erosion. Soil with higher clay content has the higher capability of preventing soil from wind erosion than one with the opposite one under the together action of PAM and water. PMID:18085418

He, Ji-Jun; Cai, Qiang-Guo; Tang, Ze-Jun

2008-10-01

71

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

72

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

73

Climatic controls on steady state erosion using the relationship between channel steepness and cosmogenic 10Be-derived catchment averaged erosion rates  

NASA Astrophysics Data System (ADS)

To understand landscape response to climate change, baseline controls on erosion rates must be established for given climate conditions. Theory suggests a number of climate metrics should be important to erosion (i.e. precipitation, temperature, storminess, seasonality, snow fraction). Nevertheless, definitive field evidence quantifying how climate affects erosion rate has proven difficult to obtain. This is at least partly due to the difficulty of isolating climatic influences on erosion rates from topographic and rock strength influences. We circumvent this problem by evaluating how climate influences the relationship between erosion rate and topography in settings with similar rock types. At steady state, tectonic uplift dictates erosion rate, and climate and rock strength are manifest as changes in erosional efficiency - the topographic relief necessary to maintain the tectonically imposed erosion rate. In fluvial landscapes, bedrock rivers set the relevant scale of topographic relief, which can be described by the channel steepness index. A number of recent studies have shown that the relationship between channel steepness and millennial scale erosion rates is non-linear, implying that erosional efficiency increases with relief. Work in the San Gabriel Mountains suggests this relationship is due to erosion thresholds that limit incision of channels in low relief landscapes. By using a fluvial incision model that incorporates a range of daily discharge events coupled with an erosion threshold (Lague et al., 2005), the influence of flood frequency on the relationship between channel steepness and erosion rate can be explored. We apply this same modeling approach to five other landscapes that exhibit a range of channel steepness, have similar rock types (granitoids), but that are in dramatically different climate regimes ranging from desert to rainforest (annual rainfall, P, from 0.25 to 3 m/yr). Specifically, we present new cosmogenic 10Be erosion rate data from the San Jacinto Mountains, CA (P = ~0.25 m/yr); Sierra San Pedro Martir, MX (P = ~0.25 m/yr); Sangre de Cristo Mountains, NM (P = ~1 m/yr); North Sierra Nevada, CA (P = ~2 m/yr); Sierra Nombre de Dios, HN (P = ~3 m/yr). These landscapes exhibit large differences in mean annual precipitation, mean annual temperature, mean daily runoff, and runoff variability. Using long time-series hydrological and meteorological data, we assess the capabilities and limitations of stochastic-threshold incision models for predicting the relationship between channel steepness and erosion rate. Further, we document quantifiable changes in erosional efficiency for differing climate conditions that can be used as a baseline for interpreting the effects of climate change in steep mountain catchments.

Rossi, M. W.; Whipple, K. X.; DiBiase, R. A.; Heimsath, A. M.

2011-12-01

74

Controls on slope-wash erosion rates in the Mojave Desert  

NASA Astrophysics Data System (ADS)

This study estimates the rates of soil erosion by slope wash in an arid region and the various factors that control these rates. Decadal-scale erosion rates were estimated on hillslope scales using inventories of 137Cs that were sampled from 46 soil profiles in four different study sites in the Mojave Desert. Calculated mean soil erosion rates per site range from -3.6 to -24.3 t ha-1 yr-1. Higher mean rates were associated with gently sloping sites that exhibit low percentage of rock and vegetation coverage, whereas lower mean rates corresponded to steep and rocky sites. Individual erosion rates were not correlated to slope gradient or curvature but were negatively correlated with the volume fraction of rocks in the upper soil profile (i.e., upslope rock coverage). Since the slopes get rockier as they get steeper, any increase in erosion rates with increasing slope is outweighed by the inhibiting effect of greater rock cover. This, together with sandy-loam soil texture on the steep slopes hinders runoff and erosion. Our findings are supported by soil data that show greater heterogeneity in the degree of calcic soil development and higher soluble salt contents in more gently sloping sites that are characterized by high erosion rates. The erosion rates reported here for the gently sloping sites are higher than rates calculated for semi-arid regions, probably due to the lower rock and vegetation coverage in these sites compared to wetter areas. These rates are also higher than millennial-scale rates estimated for the Mojave Desert on watershed scales, and suggest that at least part of the eroded sediments are stored in the adjacent streams and do not reach the piedmonts.

Crouvi, O.; Polyakov, V. O.; Pelletier, J. D.; Rasmussen, C.

2014-06-01

75

The topographic controls on the decadal-scale erosion rates in Qilian Shan Mountains, N.W. China  

NASA Astrophysics Data System (ADS)

The relationships between climate, topography, and erosion are significant in understanding landscape evolution. In order to study this relationship in a tectonically active landscape, the details of 11 drainage basins were collected from Qilian Shan Mountains. Decadal-scale erosion rates, including the mechanical load and solute load contributions, are estimated in natural conditions. The calculated erosion rates show that the average erosion rate of Qilian Shan Mountains is about 0.08 mm/yr, while the variation of annual erosion rates within each basin is significant. The changes of topography and climate, which potentially control erosion rates, are also employed in this paper for correlating analyses. Correlation analyses indicate that erosion rates are more closely correlated with topographic variables, such as mean local relief and mean slope, than all of the climatic variables; and mean local relief and decadal-scale erosion rates show a linear relationship in these tectonically active mountains. However, some topographic variables like basin area and elongation ratio exert limited influence on erosion rates; while others, such as basin elevation, basin relief and basin roughness, show poor correlation. The results indicate that topographic control, like aspects of the local terrain steepness, plays the most important role in spatial distribution of decadal-scale erosion rates throughout Qilian Shan Mountains. Under topographic control, some climatic variables, like discharge and runoff, however, could account for the significant variation of annual erosion rates in individual basin. When comparing erosion rates on different timescales, we found that the decadal-scale erosion rates are lower than the long-term river incision rates, as well as the exhumation rates during early and middle Miocene. The change to more arid climatic condition since the middle Miocene combining with tectonic uplift should attribute to the inconsistent erosion rates over different timescales in Qilian Shan Mountains.

Pan, Bao-tian; Geng, Hao-peng; Hu, Xiao-fei; Sun, Ran-hao; Wang, Chao

2010-03-01

76

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

77

Comprehensive Erosion and Sediment Control Training Program for Engineers, Architects and Planners.  

ERIC Educational Resources Information Center

This program training text was designed to provide uniform instruction to the engineer, architect, planner, and others who will be helping to implement an erosion and sediment control program. Although tailored for use in Virginia, the basic principles covered are universal, and the material is adaptable to meet the needs in any State. The 11…

Porter, Harry L., Jr.

78

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.

79

Evaluation of chemical stabilizers and windscreens for wind erosion control of uranium mill tailings  

Microsoft Academic Search

Potential wind erosion of uranium mill tailings is a concern for the surface disposal of tailings at uranium mills. Wind-blown tailings may subsequently be redeposited on areas outside the impoundment. Pacific Northwest Laboratory (PNL) is investigating techniques for fugitive dust control at uranium mill tailings piles. Laboratory tests, including wind tunnel studies, were conducted to evaluate the relative effectiveness of

M. R. Elmore; J. N. Hartley

1984-01-01

80

Prediction of vegetation restoration by erosion control works in Asio copper mine, Japan  

Microsoft Academic Search

At devastated land around the Asio copper mine and the progress of vegetation restoration was studied using remote sensing and GIS. Vegetation restoration was studied to evaluate the success of erosion control works (revegetation works). To estimate vegetation status using vegetation index, Mitscherlich's growth curve was applied to the restoration process in both the works area and non works area.

Kiyoshi Honda; Shunji Murai; Ryousuke Shibasaki

1993-01-01

81

A Buried Pipe System for Controlling Erosion and Sediment Loss on Irrigated Land1  

Microsoft Academic Search

ABSTRACT A new system comprised of a buried pipe, with riser inlets from the surface at intervals, along the lower end of furrow-irrigated fields was designed, installed, and evaluated on 21 fields to determine its effective- ness as an erosion and sediment loss control system for irrigated land. The system utilizes small sediment collection ponds with the riser inlets from

D. L. Carter; R. D. Berg

1983-01-01

82

PERFORMANCE ASSESSMENT OF WOOD STRAND EROSION CONTROL MATERIALS AMONG VARYING SLOPES, SOIL TEXTURES AND COVER AMOUNTS  

Microsoft Academic Search

Two blends of manufactured wood strands with different lengths were tested for effectiveness in controlling erosion. Wood strand blends were tested on two soils, two slope steepnesses, and at three coverage amounts. Laboratory rainfall simulations were conducted to evaluate runoff and sediment loss. Wood strands were effective in delaying runoff, reducing runoff volume, and reducing sediment loss. There was no

Kristina Anne Yanosek; Randy Bruce Foltz; James Henry Dooley

83

7Be and hydrological model for more efficient implementation of erosion control measure  

NASA Astrophysics Data System (ADS)

Increased concern about the on-site and off-site impacts of soil erosion in agricultural and forested areas has endorsed interest in innovative methods to assess in an unbiased way spatial and temporal soil erosion rates and redistribution patterns. Hence, interest in precisely estimating the magnitude of the problem and therefore applying erosion control measures (ECM) more efficiently. The latest generation of physically-based hydrological models, which fully couple overland flow and subsurface flow in three dimensions, permit implementing ECM in small and large scales more effectively if coupled with a sediment transport algorithm. While many studies focused on integrating empirical or numerical models based on traditional erosion budget measurements into 3D hydrological models, few studies evaluated the efficiency of ECM on watershed scale and very little attention is given to the potentials of environmental Fallout Radio-Nuclides (FRNs) in such applications. The use of FRN tracer 7Be in soil erosion/deposition research proved to overcome many (if not all) of the problems associated with the conventional approaches providing reliable data for efficient land use management. This poster will underline the pros and cones of using conventional methods and 7Be tracers to evaluate the efficiency of coconuts dams installed as ECM in experimental field in Belgium. It will also outline the potentials of 7Be in providing valuable inputs for evolving the numerical sediment transport algorithm needed for the hydrological model on field scale leading to assess the possibility of using this short-lived tracer as a validation tool for the upgraded hydrological model on watershed scale in further steps. Keywords: FRN, erosion control measures, hydrological modes

Al-Barri, Bashar; Bode, Samuel; Blake, William; Ryken, Nick; Cornelis, Wim; Boeckx, Pascal

2014-05-01

84

Beach Erosion Control Project Sherwood Island State Park, Westport, Connecticut.  

National Technical Information Service (NTIS)

Beach widening and sand retention structures are proposed along 6,000 feet of shorefront at Sherwood Island State Park, Town of Westport, Fairfield County, Connecticut. Environmental impacts include restoration and protection of valuable beach fronting on...

1973-01-01

85

How can we control erosion of roadslopes in semiarid mediterranean areas? Soil improvement and native plant establishment  

Microsoft Academic Search

ABSTRACT Road building triggers vegetation and soil degradation which affects road safety. We present conclusive results in terms of roadslope protection against erosion from several studies performed,on semiarid roadslopes since 2000 (in Eastern Spain). We aim to (1) improve our understanding,about slope and vegetation factors which control soil erosion and plant colonisation on semiarid roadslopes; (2) assess the effectiveness of

E. Bochet; P. García-Fayos; J. Tormo

2010-01-01

86

Controlled ultrasound tissue erosion: The role of dynamic interaction between insonation and microbubble activity  

PubMed Central

Previous studies showed that ultrasound can mechanically remove tissue in a localized, controlled manner. Moreover, enhanced acoustic backscatter is highly correlated with the erosion process. “Initiation” and “extinction” of this highly backscattering environment were studied in this paper. The relationship between initiation and erosion, variability of initiation and extinction, and effects of pulse intensity and gas saturation on time to initiation (initiation delay time) were investigated. A 788-kHz single-element transducer was used. Multiple pulses at a 3-cycle pulse duration and a 20-kHz pulse repetition frequency were applied. ISPPA values between 1000 and 9000 W/cm2 and gas saturation ranges of 24%–28%, 39%–49%, and 77%–81% were tested. Results show the following: (1) without initiation, erosion was never observed; (2) initiation and extinction of the highly backscattering environment were stochastic in nature and dependent on acoustic parameters; (3) initiation delay times were shorter with higher intensity and higher gas saturation (e.g., the mean initiation delay time was 66.9 s at ISPPA of 4000 W/cm2 and 3.6 ms at ISPPA of 9000 W/cm2); and (4) once initiated by high-intensity pulses, the highly backscattering environment and erosion can be sustained using a significantly lower intensity than that required to initiate the process.

Xu, Zhen; Fowlkes, J. Brian; Rothman, Edward D.; Levin, Albert M.; Cain, Charles A.

2009-01-01

87

Consistency of Rain Splash Soil Erosion under Controlled Laboratory Flume Conditions  

NASA Astrophysics Data System (ADS)

Prediction of soil erosion is challenging due to the wide range of factors that can affect it. At the catchment scale, for instance, inconsistent soil erosion yields have been reported in numerous studies. Explanations involve nonlinearities in these contributing factors and their interactions (such as soil surface properties, precipitation characteristic, topography and land cover). Controlled laboratory flume experiments provide a means to improve our process physical understanding. Here, we report on experiments wherein the dependence of rain-splash soil erosion on the precipitation rate, area of soil exposed and initial soil conditions was investigated using laboratory flume experiments. The role of these factors on predicting experimental results was examined based on a prototype experiment and area-based approach. That is, we hypothesised that flume erosion can be predicted by a simple linear scaling of the different factors. Fourteen experiments were carried out in which we varied the precipitation rate (28, 60 and 74 mm/h), the fraction of surface rock fragments (20, 30, and 40%) and initial soil conditions (dry hand-cultivated, wet sealed-compacted and dry compacted). In addition, the influence of time was investigated by considering different experiment durations (2-5 h). In all experiments, we measured the discharge rate, the total sediment concentration and the sediment concentrations of the individual size classes at the flume exit. The presence of surface rock fragments on the soil surface prevents surface sealing and reduces the cross-sectional area available for flow, thereby affecting the development of steady-state equilibrium. Results revealed that, generally, estimates of the individual size classes' sediment concentrations, taking the exposed area into account, reproduce satisfactorily the measured data at steady state, independent of the initial conditions and rainfall intensity. Before steady state, however, the main feature in most sediment size classes is an early concentration peak, which was found not to be proportional to the area exposed and effective rainfall. Rather, results showed that the short time behaviour is mainly controlled by the soil antecedent and initial conditions, such as surface sealing, surface compaction and soil moisture. In addition, findings suggested that the larger size classes are more sensitive to prior soil conditions than the finer size classes. It was found, also, that this proportionality of erosion to area of exposed soil can be obtained for the entire erosive event under carefully controlled conditions. Steady state erosion rates, based on a prototype precipitation, were within a factor two of measured rates, for total and individual size classes. However, at short times, erosion due to raindrop splash is not proportionally controlled by the precipitation rate. Overall, the results thus indicate that, for a given soil, experimental data based on a given rainfall rate can be used as a rough estimator of the steady rate of erosion for a different rainfall rates.

Jomaa, Seifeddine; Barry, D. Andrew; Sander, Graham G.; Parlange, J.-Yves

2014-05-01

88

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

89

Runoff and sediment response to erosion control measures in a 300 ha cultivated catchment (Belgium)  

NASA Astrophysics Data System (ADS)

In order to reduce soil erosion and its downstream effects, policy actions have been taken, especially in Flanders (Belgium). These actions provide subsidies to the municipalities, landowners and farmers in the hilly regions of Flanders to implement erosion control measures. The reduction of severe soil erosion in the hilly regions of Flanders and the mitigation of muddy flooding of villages are the main goals or objectives of these policy actions. Numerous measures (e.g. grass bufferstrips, grassed waterways, small retention dams,...) have been installed in the Melsterbeek pilot catchment (circa 200 km²) since 2002. Since 2005 the local water agency has started a monitoring program in order to assess the effects of the control measures installed. This monitoring is both qualitative (e.g. field observations) and quantitative (e.g. monitoring of a well-equipped 300 ha cultivated catchment). Between 2002 and 2004 a grassed waterway, covering an area of 12 ha, as well as three earthen dams were installed in the 300-ha catchment. Rainfall-runoff events have been measured between 2005 and 2008. Runoff peak discharge at the outlet of the 300 ha cultivated catchment was reduced by more than 60 % with mitigation measures. Furthermore, runoff was buffered for 5 to 12 hours behind the dams, and the lag time at the outlet of the catchment was thereby increased by 75 %. Reinfiltration was mainly observed within the grassed waterway during low intensity storms. In contrast, the reinfiltration during intense storms was very low. No (ephemeral) gully has formed in this catchment since the installation of the control measures, thereby reducing erosion and interrill phenomenon. Specific sediment yield dropped from 3.5 t ha-1 yr-1 to a mean of 0.5 t ha-1 yr-1 after the installation of the control measures. Hence, sediment transfer from the cultivated dry valley to the alluvial plain should dramatically decrease. The control measures served their purpose by preventing severe soil erosion and muddy flooding in the downstream village despite the occurrence of several extreme rainfall events. Similar measures should therefore be installed to protect other flooded villages of the Belgian loess belt and comparable environments.

Vandaele, K.; Evrard, O.; Swerts, M.; Lammens, J.; Priemen, P.; van Wesemael, B.; de Vrieze, M.

2009-04-01

90

Performance and efficiency of geotextile-supported erosion control measures during simulated rainfall events  

NASA Astrophysics Data System (ADS)

Erosion control systems consisting of technical and biological components are widely accepted and proven to work well if installed properly with regard to site-specific parameters. A wide range of implementation measures for this specific protection purpose is existent and new, in particular technical solutions are constantly introduced into the market. Nevertheless, especially vegetation aspects of erosion control measures are frequently disregarded and should be considered enhanced against the backdrop of the development and realization of adaptation strategies in an altering environment due to climate change associated effects. Technical auxiliaries such as geotextiles typically used for slope protection (nettings, blankets, turf reinforcement mats etc.) address specific features and due to structural and material diversity, differing effects on sediment yield, surface runoff and vegetational development seem evident. Nevertheless there is a knowledge gap concerning the mutual interaction processes between technical and biological components respectively specific comparable data on erosion-reducing effects of technical-biological erosion protection systems are insufficient. In this context, an experimental arrangement was set up to study the correlated influences of geotextiles and vegetation and determine its (combined) effects on surface runoff and soil loss during simulated heavy rainfall events. Sowing vessels serve as testing facilities which are filled with top soil under application of various organic and synthetic geotextiles and by using a reliable drought resistant seed mixture. Regular vegetational monitoring as well as two rainfall simulation runs with four repetitions of each variant were conducted. Therefore a portable rainfall simulator with standardized rainfall intensity of 240 mm h-1 and three minute rainfall duration was used to stress these systems on different stages of plant development at an inclination of 30 degrees. First results show significant differences between the systems referring to sediment yield and runoff amount respectively vegetation development.

Obriejetan, Michael; Rauch, Hans Peter; Florineth, Florin

2013-04-01

91

Beach Erosion  

NSDL National Science Digital Library

The Beach Erosion site of the WhyFiles (last mentioned in the August 9, 1996 Scout Report), a project funded by the graduate school of the University of Wisconsin-Madison, has been recently updated. Its newest addition includes a story about the population of the tiny Pacific Island nation of Tuvalu that is preparing to abandon its home due to rising sea levels. The site takes a look at this subject and the resulting increased beach erosion that takes place around the world. Visitors can read about the physical processes of beach erosion, view a QuickTime movie of a house falling into the ocean, and more. The site includes good descriptions, photographs, and links to additional information (although some were broken at the time of this annotation), giving interested readers insight into this widespread phenomenon.

1999-01-01

92

Direct and indirect impacts of climate change on soil erosion and land degradation in Mediterranean watersheds: a presentation of the ERLAND project  

NASA Astrophysics Data System (ADS)

This presentation will describe the recently-approved ERLAND project (2010-2013), whose main aim is to estimate the impacts of climate change on soil erosion in representative Portuguese agroforestry watersheds, due to changes in rainfall, runoff generation and vegetation cover. Soil erosion is a critical driver for desertification in Mediterranean regions, degrading the soil's capacity to sustain vegetation under marginal climatic conditions. An increase in climatic aridity, caused by global climate change, could lead to increases or decreases in erosion, depending on the interaction between lower rainfall and lower vegetation biomass productivity The main objective of ERLAND is to characterize the most important impacts climate change could cause on different erosive processes within Mediterranean catchments, and help define the costs and benefits of different adaptation options. The project explicitly addresses important limitations of similar past studies, such as: (i) lack of appropriate downscaling of climate change scenarios; (ii) focus on hillslope or, in rare instances, channel processes, ignoring gully erosion; or (iii) lack of sufficient erosion data for the proper evaluation of the erosion models used in these assessments. The main analysis tool will be a new vegetation, runoff and erosion model, built by joining together existing and widely tested concepts to simulate vegetation, hydrology and erosion. It will aim at the continuous simulation of sediment detachment and transport within catchments, using a detailed simulation of spatial patterns while simplifying the simulation of temporal patterns, allowing for a multi-year application. The project will focus on two catchments, corresponding to typical combinations of climate and land cover/use under humid and dry climate conditions: in northern Portugal, eucalypt/pine commercial forestry combined with annual cultures or vineyards; in southern Portugal, extensive cork oak forestry (montado) associated with annual cultures or pastures. Data on climate, vegetation, hydrology and soil erosion will be collected at different spatial scales (hillslope, gullies, catchment), to allow for a correct calibration of the model in simulating the most important erosive processes for current conditions. Climate change scenarios for 2071-2100 will be downscaled for the study areas based on existing regional climate models through a statistical approach. Results are expected to provide insights on the erosive impacts of changes in key erosive factors, i.e.: rainfall regime, vegetation cover (including increased wildfire frequency), soil moisture and hydrological regimes. Impacts will be assessed in terms of soil loss at the slope scale, gully erosion processes and catchment sediment yield. Scenarios for land-use change and agroforestry adaptation due to climate change will also be developed and tested using the model. ERLAND will represent one of the few studies performed for Mediterranean conditions, and explicitly including gully erosion and sediment connectivity.

Nunes, João. Pedro; Corte-Real, João.; Keizer, Jan Jacob; Abrantes, Nelson; César Lima, Júlio; Roebeling, Peter; Sampaio, Elsa; Santos, João.; Eufémia Varela, Maria

2010-05-01

93

Use of Sediment Budgets for Watershed Erosion Control Planning: A Case Study From Northern California  

NASA Astrophysics Data System (ADS)

Erosion, sedimentation and peak flow increases caused by forest management for commercial timber production may negatively affect aquatic habitat of endangered anadromous fish such as coho salmon ({\\ it O. kisutch}). This paper summarizes a portion of a Watershed Analysis study performed for Pacific Lumber Company, Scotia, CA, focusing on erosion and sedimentation processes and rates and downstream sediment routing and water quality in the Freshwater Creek watershed in northwest California. Hillslope, road and bank erosion, channel sedimentation and sediment rates were quantified using field surveys, aerial photo interpretation, and empirical modeling approaches for different elements of the study. Sediment transport rates for bedload were modeled, and sediment transport rates for suspended sediment were estimated based on size distribution of sediment inputs in relation to sizes transported in suspension. The resulting sediment budget was validated through comparison using recent short-term, high-quality estimates of suspended sediment yield collected by a community watershed group at a downstream monitoring site with technical assistance from the US Forest Service. Another check on the sediment budget was provided by bedload yield data from an adjacent watershed, Jacoby Creek. The sediment budget techniques and bedload routing models used for this study provide sediment yield estimates that are in good agreement with available data. These results suggest that sediment budget techniques that require moderate levels of fieldwork can be used to provide relatively accurate technical assessments for use in the TMDL process. The sediment budget also identifies the most significant sediment sources and suggests a framework within which effective erosion control strategies can be developed.

O'Connor, M.; McDavitt, W.

2002-05-01

94

Materials for Advanced Turbine Engines (MATE). Project 4: Erosion resistant compressor airfoil coating  

NASA Technical Reports Server (NTRS)

The ability of coatings to provide at least a 2X improvement in particulate erosion resistance for steel, nickel and titanium compressor airfoils was identified and demonstrated. Coating materials evaluated included plasma sprayed cobalt tungsten carbide, nickel carbide and diffusion applied chromium plus boron. Several processing parameters for plasma spray processing and diffusion coating were evaluated to identify coating systems having the most potential for providing airfoil erosion resistance. Based on laboratory results and analytical evaluations, selected coating systems were applied to gas turbine blades and evaluated for surface finish, burner rig erosion resistance and effect on high cycle fatigue strength. Based on these tests, the following coatings were recommended for engine testing: Gator-Gard plasma spray 88WC-12Co on titanium alloy airfoils, plasma spray 83WC-17Co on steel and nickel alloy airfoils, and Cr+B on nickel alloy airfoils.

Rashid, J. M.; Freling, M.; Friedrich, L. A.

1987-01-01

95

MONITORING AND CONTROLLING SOFTWARE DEVELOPMENT PROJECTS  

Microsoft Academic Search

Software development projects are seldom able to be planned so accurately that the plans predict exactly what will happen during the project. Project managers must monitor the project and make changes either to the project's activities or to the plan itself. Yet much of the project management literature gives only cursory attention to the problem of monitoring and controlling the

Tom McBride

96

Substation control and protection project  

SciTech Connect

This report describes the results of EPRI-sponsored Project RP1359-7, dealing with digital protection and control of transmission class substations. Earlier work involved a study of the feasibility of an integrated protection and control system, specification of functional requirements and selection of the optimum architecture for the system. An integrated system including line, bus and transformer protection was designed, built and laboratory tested. It was subsequently installed at the Deans substation of Public Service Electric and Gas (New Jersey). A standalone, digital transmission line system was built and installed at the Branchburg substation of PSE G, for coordinated line protection with the integrated system. The system is called WESPAC, an acronym for Westinghouse Substation Protection and Control. 52 refs., 174 figs.

Cassel, R.L.; Deliyannides, J.S.; Dzieduszko, J.W.; Harvey, J.H.; Hertz, L.H.; Klancher, F.; Mays, L.M.; McGarry, M.J.; Pettis, L.G.; Pistolese, L.F.; Reuther, J.F.; Sackin, M.; Szarmach, D.J.; Udren, E.A. (Westinghouse ABB Power T and D Co., Coral Springs, FL (USA). Relay and Telecommunications Div.)

1990-04-01

97

Costs and benefits of urban erosion and sediment control: The North Carolina experience  

NASA Astrophysics Data System (ADS)

The EPA’s new nonpoint source pollution control requirements will soon institutionalize urban erosion and sediment pollution control practices nationwide. The public and private sector costs and social benefits associated with North Carolina’s program (one of the strongest programs in the country in terms of implementation authority, staffing levels, and comprehensiveness of coverage) are examined to provide general policy guidance on questions relating to the likely burden the new best management practices will have on the development industry, the likely costs and benefits of such a program, and the feasibility of running a program on a cost recovery basis. We found that urban erosion and sediment control requirements were not particularly burdensome to the development industry (adding about 4% on average to development costs). Public-sector program costs ranged between 2.4 and 4.8 million in fiscal year 1989. Our contingent valuation survey suggests that urban households in North Carolina are willing to pay somewhere between 7.1 and 14.2 million a year to maintain current levels of sediment pollution control. Our benefit-cost analysis suggests that the overall ratio is likely to be positive, although a definitive figure is elusive. Lastly, we found that several North Carolina localities have cost recovery fee systems that are at least partially self-financing.

Paterson, Robert G.; Luger, Michael I.; Burby, Raymond J.; Kaiser, Edward J.; Malcom, H. Rooney; Beard, Alicia C.

1993-03-01

98

Can Warmwater Streams Be Rehabilitated Using Watershed-Scale Standard Erosion Control Measures Alone?  

NASA Astrophysics Data System (ADS)

Degradation of warmwater streams in agricultural landscapes is a pervasive problem, and reports of restoration effectiveness based on monitoring data are rare. Described is the outcome of rehabilitation of two deeply incised, unstable sand-and-gravel-bed streams. Channel networks of both watersheds were treated using standard erosion control measures, and aquatic habitats within 1-km-long reaches of each stream were further treated by addition of instream structures and planting woody vegetation on banks (“habitat rehabilitation”). Fish and their habitats were sampled semiannually during 1-2 years before rehabilitation, 3-4 years after rehabilitation, and 10-11 years after rehabilitation. Reaches with only erosion control measures located upstream from the habitat measure reaches and in similar streams in adjacent watersheds were sampled concurrently. Sediment concentrations declined steeply throughout both watersheds, with means ?40% lower during the post-rehabilitation period than before. Physical effects of habitat rehabilitation were persistent through time, with pool habitat availability much higher in rehabilitated reaches than elsewhere. Fish community structure responded with major shifts in relative species abundance: as pool habitats increased after rehabilitation, small-bodied generalists and opportunists declined as certain piscivores and larger-bodied species such as centrarchids and catostomids increased. Reaches without habitat rehabilitation were significantly shallower, and fish populations there were similar to the rehabilitated reaches prior to treatment. These findings are applicable to incised, warmwater streams draining agricultural watersheds similar to those we studied. Rehabilitation of warmwater stream ecosystems is possible with current knowledge, but a major shift in stream corridor management strategies will be needed to reverse ongoing degradation trends. Apparently, conventional channel erosion controls without instream habitat measures are ineffective tools for ecosystem restoration in incised, warmwater streams of the Southeastern U.S., even if applied at the watershed scale and accompanied by significant reductions in suspended sediment concentration.

Shields, F. Douglas; Knight, Scott S.; Cooper, Charles M.

2007-07-01

99

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

100

The role of forest stand density in controlling soil erosion: implications to sediment-related disasters in Japan  

Microsoft Academic Search

The role of forest stand density in controlling soil erosion was investigated in Ehime Prefecture, Japan. The main objective\\u000a was to compare soil erosion under different forest conditions including forest type, species composition, and stand density\\u000a as influenced by thinning operations. Relative yield index (Ry) was used as an indicator of stand density to reflect the degree\\u000a of management operations

Bam H. N. Razafindrabe; Bin He; Shoji Inoue; Tsugio Ezaki; Rajib Shaw

2010-01-01

101

Analysis/control of in-bed tube erosion phenomena in the fluidized bed combustion (FBC) system. Technical progress report No. 2, [January 1, 1993--March 31, 1993  

SciTech Connect

This technical report summarizes the research work performed and the progress achieved during the period of January 1, 1993 to March 31, 1993. The prototype dust collector as a part of the exhaust system was designed and fabricated to perform the well-controlled test in the bench-scale FBC system. The instrumentation for flow-measuring has been conducted in the system, which includes the minimum fluidization velocity and bed-pressure drop, mean gas velocity, calculation of particle terminal velocity and its operating range, and static pressure distribution in the system. The bubble velocity was also predicted. The project has been progressing well. Future efforts will be concentrated on instrumentation for erosion-measuring. In addition to that, instrumentation for flow-measuring will be continued to support the erosion-measuring. Theoretical analysis and modeling on in-bed tube erosion will be initiated along with the experimental results. Experience and observation of in-bed tube erosion will be predicted.

Lee, Seong W.

1993-06-01

102

Low cost forged Y-pattern valves control hot corrosive/erosive gases  

SciTech Connect

The Morgantown Energy Technology Center in Morgantown, West Virginia is a research facility of the US Department of Energy (DOE) that does research on fossil fuels utilization and conversion to provide improved and environmentally acceptable energy sources. One area of investigation in the Morgantown facility is the use of gaseous fuels derived from coal from fluidized-bed and fixed-bed gasification technologies. The corrosive and slightly erosive gases and vapors at about 1000F and from 100 to 300 psi are treated in an experimental desulfurization unit to produce fuel gas with greatly enhanced environmental characteristics. The valves in use were constructed of Type 347 stainless steel, a stabilized version of 316 SS, and cost about $6000 for the 2'' size and about $4000 for the 1'' size. Despite the high cost, the valve sometimes became difficult or impossible to operate due to metal failures. The Technology Center had a number of new Class 1500 Y-pattern (angle-style) globe valves in inventory. The control valve body and bonnet are forged chrome moly steel (ASTM-H182-F22), the stem assembly is a 13% chrome alloy with an erosion resistant hard faced disc, and the seat ring is a cobalt-base alloy fused in place as an integral part of the body. Stem packing as an either wire inserted molded asbestos or Grafoil flexible graphite. The Y-pattern globe valves in 1 and 2'' sizes, which were judged potentially suitable and on hand, were installed in the experimental desulfization unit as well as in the connecting hot gas piping system to a new coal gasification process. The Class 1500 Y-pattern valves have provided reliable control of the hot corrosive and erosive gas streams with very little maintenance.

Gaines, A.

1987-06-01

103

Robotic weld overlay coatings for erosion control. [Quarterly report, July--September 1993  

SciTech Connect

In the previous period of work, twelve overlay hardfacing alloys were selected for erosion testing based upon a literature review. All twelve 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 previous quarterly report. During the past quarter, all the coatings were erosion tested at 400 C. The erosion resistance of each coating was evaluated by determining the steady state erosion rate. In addition, the microstructure of each coating was characterized before and after the erosion tests. This progress report describes the erosion test results and coating microstructures. Also, a preliminary analysis on the relationships, between weld overlay coating hardness, microstructure, and erosion resistance will be discussed.

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

1993-10-20

104

Ecosystem services in Mediterranean river basin: climate change impact on water provisioning and erosion control.  

PubMed

The Mediterranean basin is considered one of the most vulnerable regions of the world to climate change and such changes impact the capacity of ecosystems to provide goods and services to human society. The predicted future scenarios for this region present an increased frequency of floods and extended droughts, especially at the Iberian Peninsula. This paper evaluates the impacts of climate change on the water provisioning and erosion control services in the densely populated Mediterranean Llobregat river basin of. The assessment of ecosystem services and their mapping at the basin scale identify the current pressures on the river basin including the source area in the Pyrenees Mountains. Drinking water provisioning is expected to decrease between 3 and 49%, while total hydropower production will decrease between 5 and 43%. Erosion control will be reduced by up to 23%, indicating that costs for dredging the reservoirs as well as for treating drinking water will also increase. Based on these data, the concept for an appropriate quantification and related spatial visualization of ecosystem service is elaborated and discussed. PMID:23660520

Bangash, Rubab F; Passuello, Ana; Sanchez-Canales, María; Terrado, Marta; López, Alfredo; Elorza, F Javier; Ziv, Guy; Acuña, Vicenç; Schuhmacher, Marta

2013-08-01

105

Orbital controls on paleo erosion rates in the Western Escarpment of the Andes at 13° latitude  

NASA Astrophysics Data System (ADS)

The formation of fluvial terrace sequences in mountainous areas requires that two boundary conditions have to be fulfilled. First, hilllslope material available for erosion needs to be sufficiently thick and abundant. Second stripping off of this regolith cover has to occur fast and within a short time period. Contrariwise, if hillslope erosion operates at a pace concordant with the fluvial regime and in equilibrium to the prevailing climate, then no terrace sequence will form. Here, we present a 10Be-based sediment budget from the cut-and-fill terrace sequences in the Pisco valley, and particularly the Minchin terrace sequence deposited between 48-36 ka, to illustrate how the erosional regime and the precipitation pattern has changed in response to orbitally-driven climate cycles. We find that the Minchin period was characterized by an erosional pulse along the Pacific coast during which denudation rates reached values as high as 600 mm/ka (provided that the lateral valley flanks have been the major sediment source) for a relatively short time span lasting a few thousands of years. This contrasts to the younger orbitally-controlled pluvial periods and the modern situation when 10Be-based sediment budgets yield nearly zero erosion at the Pacific coast. We interpret these contrasts to indicated different erosional conditions between the modern and the Minchin time. First, the sediment budget infers a precipitation pattern that is similar to the modern climate ca. 1000 km farther north near the boundary between Peru and Ecuador, where highly erratic and extreme El Niño-related precipitation are associated with landsliding and flooding along the coast. Second, the formation of a thick terrace sequence requires the supply of sufficient material through erosion on the catchment's hillslopes. It is likely that a relatively thick regolith sequence had accumulated before the start of the Minchin period, because this erosional epoch was preceded by a >50 ka-long time span with dry conditions, allowing for sufficient regolith to build up on the hillslopes. Finally, this study suggests a strong control of orbitally and ice sheet forced latitudinal shifts of the ITCZ on the erosional gradients and sediment production on the western escarpment of the Peruvian Andes at 13° during the Minchin period. Accordingly, cut-and-fill sequences cannot only be inverted into contrasting erosional regimes, but also into different paleogeographic and paleoecological conditions.

Schlunegger, Fritz; Bekaddour, Toufik; Delunel, Romain; Norton, Kevin; Akçar, Naki; Vogel, Hendrik

2014-05-01

106

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

Microsoft Academic Search

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

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

1993-01-01

107

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

108

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

109

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

110

Toxicity of anionic polyacrylamide formulations when used for erosion control in agriculture.  

PubMed

Addition of anionic polyacrylamide (PAM) to agricultural irrigation water can dramatically reduce erosion of soils. However, the toxicity of PAM to aquatic life, while often claimed to be low, has not been thoroughly evaluated. Five PAM formulations, including two oil-based products, one water-based product, one granular product and one tablet product, were evaluated for acute and/or chronic toxicity to five species commonly used for freshwater toxicity testing [Hyalella azteca (Saussure), Chironomus dilutus (Shobanov et al.), Ceriodaphnia dubia (Richard), Pimephales promelas (Rafinesque), and Selenastrum capricornutum (Printz)]. When applied as an oil-based product, acute toxicity was seen to four of the five species at concentrations less than the 10 mg/L that is often used for erosion control. Toxicity was diminished, but still remained, after passage of the irrigation water across an agricultural field, indicating a potential impact to nearby surface waters. Results from the non-oil-based products indicated minimal toxicity associated with PAM even at concentrations 10 times those used in agriculture when applied in the granular form, as a tablet, or in a water-based liquid. These data suggest that other agents in the oil-based products, such as surfactants or emulsifiers, rather than the PAM itself, contribute to the toxicity. Care is required in selecting an appropriate PAM formulation when the potential exists for entry of tailwater to nearby surface waters. PMID:19141814

Weston, Donald P; Lentz, Rodrick D; Cahn, Michael D; Ogle, R Scott; Rothert, Amanda K; Lydy, Michael J

2009-01-01

111

Cropping systems and control of soil erosion in a Mediterranean environment  

NASA Astrophysics Data System (ADS)

The research has been carried out over the years 1996-2010 in an area of the internal hill of Sicily region (Enna, c.da Geracello, 550 m a. s. l. 37° 23' N. Lat, 14° 21' E. Long) in the center of Mediterranean Sea, mainly devoted to durum wheat cultivation, using the experimental plots, established in 1996 on a slope of 26-28%, equipped to determine surface runoff and soil losses. The establishment consists of twelve plots, having 40 m length and 8 m width. In order to study the effect of different field crop systems in controlling soil erosion in slopes subjected to water erosion, the following systems were studied: permanent crops, tilled annual crops, no-tilled annual crops, set-aside. The used crops were: durum wheat, faba bean, rapeseed, subterranean clover, Italian ryegrass, alfalfa, sweetvetch, moon trefoil, barley, sweet sorghum, sunflower. The results pointed out that the cropping systems with perennial crops allowed to keep low the soil loss, while annual crop rotation determined a high amount of soil loss. Sod seeding showed promising results also for annual crop rotations.

Cosentino, Salvatore; Copani, Venera; Testa, Giorgio; Scalici, Giovanni

2013-04-01

112

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

113

Field project control. Back to basics  

SciTech Connect

Computers and critical path method (CPM) software are the tools employed by project planning and scheduling teams to rapidly develop project schedules. It is the analysis of the CPM schedule and the follow-up actions that result in the successful completion of a project. A short duration field construction project is presented in this article which presented an opportunity for a project control engineer to apply a variety of project controls tools and techniques to the total project management effort. 1 ref., 2 figs., 1 tab.

Douglas, E.E. III (Bechtel Environmental, Inc., Oak Ridge, TN (United States))

1993-10-01

114

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

115

Open Innovation and the Erosion of the Traditional Information Systems Project's Boundaries  

NASA Astrophysics Data System (ADS)

This paper examines the notion of open innovation and its implication on information systems management. It investigates a project of an enterprise resource planning system implementation in an international organization to unravel the resemblance with the open innovation model. The study shows that the conceptualization of ERP project as an open innovation could reveal the complex architecture of today's organization from which the ERP project cannot be isolated. It argues that the traditional boundaries around IS projects are dissolving and the relationship between what used to be outside and what used to be inside the project is increasingly blurred. The study calls for a different perspective of project management that goes beyond single and multiple project management to scan the open space of innovation and actively look for partners, competitors, and collaborators.

Elbanna, Amany

116

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

117

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

118

Thermal Control System Automation Project (TCSAP).  

National Technical Information Service (NTIS)

Information is given in viewgraph form on the Space Station Freedom (SSF) Thermal Control System Automation Project (TCSAP). Topics covered include the assembly of the External Thermal Control System (ETCS); the ETCS functional schematic; the baseline Fau...

R. L. Boyer

1991-01-01

119

Construction Quality Control System of Key Water-Control Project  

Microsoft Academic Search

The quality of key water-control project is important to the improvement of national prosperity, stability and economic development. The quality control in the construction of the key water-control project is much a difficult work. So this paper tries to form a construction quality control system. It mainly contains construction quality pre-control system, construction quality process control system, optimization of the

Wang Qin; He Yabo

2010-01-01

120

Review of project control systems.  

National Technical Information Service (NTIS)

The US Department of Energy (DOE) has planned or in progress several large fossil fuel demonstration projects intended to bridge the gap between the research laboratory and commercial feasibility. Because there is developmental risk associated with plant ...

H. Bartick J. Joscelyn

1981-01-01

121

Identifying Erosion  

NSDL National Science Digital Library

In this environmental science activity (page 3 of the PDF), leaners will identify and explain the causes of erosion. They will observe the effects of erosion on the surrounding area and further explore examples of erosion online. An extension activity allows learners to make a hands-on model of soil erosion. Though this was created as a pre-visit activity for a workshop about water flow and erosion, it makes a great stand-alone activity as well!

Cosi

2009-01-01

122

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

National Technical Information Service (NTIS)

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. The...

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

1993-01-01

123

Shoreline Erosion Control Using Marsh Vegetation and Low-Cost Structures.  

National Technical Information Service (NTIS)

Erosion is a serious threat to waterfront property along most of North Carolina's extensive estuarine shoreline. It is accelerated by man's intensive use and mismanagement. As demand for shoreline property increases -- for homesites, recreational areas, m...

S. W. Broome S. M. Rogers E. D. Seneca C. B. Burgess

1992-01-01

124

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

National Technical Information Service (NTIS)

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 coa...

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

1994-01-01

125

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

126

Version Control in Project-Based Learning  

ERIC Educational Resources Information Center

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…

Milentijevic, Ivan; Ciric, Vladimir; Vojinovic, Oliver

2008-01-01

127

Project Summary: Biology-Inspired Autonomous Control.  

National Technical Information Service (NTIS)

The goal of this project is to motivate development of control concepts for autonomous munitions that overcome limitations of conventional approaches by applying principles derived from studying the biology of flying organisms. The research is focused on ...

J. H. Evers

2011-01-01

128

Late Quaternary climatic control on erosion and weathering in the eastern Tibetan Plateau and the Mekong Basin  

Microsoft Academic Search

High-resolution siliciclastic grain size and bulk mineralogy combined with clay mineralogy, rubidium, strontium, and neodymium isotopes of Core MD01-2393 collected off the Mekong River estuary in the southwestern South China Sea reveals a monsoon-controlled chemical weathering and physical erosion history during the last 190,000 yr in the eastern Tibetan Plateau and the Mekong Basin. The ranges of isotopic composition are

Zhifei Liu; Christophe Colin; Alain Trentesaux; Giuseppe Siani; Norbert Frank; Dominique Blamart; Segueni Farid

2005-01-01

129

Interdisciplinary on-site evaluation of stone bunds to control soil erosion on cropland in Northern Ethiopia  

Microsoft Academic Search

Since two decades, stone bunds have been installed in large areas of the Tigray Highlands, Northern Ethiopia, to control soil erosion by water. Field studies were conducted to quantify the effectiveness, efficiency, side effects and acceptance of stone bunds. Based on measurements on 202 field parcels, average sediment accumulation rate behind 3–21 year old stone bunds is 58tha?1year?1.The Universal Soil

Jan Nyssen; Jean Poesen; Desta Gebremichael; Karen Vancampenhout; Margo D’aes; Gebremedhin Yihdego; Gerard Govers; Herwig Leirs; Jan Moeyersons; Jozef Naudts; Nigussie Haregeweyn; Mitiku Haile; Jozef Deckers

2007-01-01

130

Stormwater control measure (SCM) design standards to limit stream erosion for Piedmont North Carolina  

NASA Astrophysics Data System (ADS)

SummaryThis study evaluated the potential impacts of sub-bankfull flows produced by stormwater control measures (SCMs) on stream geomorphic stability. In part, design standards for SCMs include peak flow attenuation to maintain pre-development flow conditions to those of undeveloped watersheds or return urbanized, developed watersheds back to the pre-developed state. Most SCMs target lower frequency storms, usually the 2-and/or 10-year discharge events, but leave peak flows resulting from higher frequency storms uncontrolled. SCMs are possibly subjecting streams to longer and more frequent periods of erosion, increasing stream channel instability. The d65 substrate size, pattern, profile, and dimension of 33 reference stream cross-sections in Piedmont North Carolina were modeled using the continuous simulations program, SWMM, to develop (1) a unit critical discharge metric in L/s/ha, Q c = 0.0035( d65) 1.5048, (2) allowable annual erosional hour standard, Log(AAEH) = -1.26Log( d65) + 1.21, and (3) allowable volume of eroded bedload standard, Log(AV) = -0.64( Q c) - 1.52, for watersheds containing SCMs discharging into surface waters. The unit critical discharge represents a threshold that, once exceeded, incipient motion of the d65 particle can occur. These standards represented benchmarks of stable, naturally eroding reference streams. Ninety-four percent of the unit critical discharges were less than the 2-year 24-h event, indicating the necessity of controlling higher frequency sub-bankfull flows. The standards were applied to an urbanized watershed (one sub-catchment containing a structural SCM and two sub-catchments without) in Raleigh, North Carolina. The unit critical discharge metric appeared to adequately represent urbanized stream geomorphic processes for the sub-catchment undergoing urbanization (4.5% difference) but not for the mature urbanized sub-catchments (47.5% and 68.8% difference). Depending on the long-term management goal of the unstable stream, this metric is not applicable for all urbanized watersheds due to the discrepancy between the field and calculated unit critical discharges. Standards developed from urbanized reference streams could possibly better represent SCMs in urbanized watersheds. All three sub-catchments failed to meet the erosional standards demonstrating the ability of the standards to predict unstable geomorphic processes in streams. The addition of a detention SCM (wet pond), in the urbanized sub-catchment extended the duration of erosive flows from 37 to 87 h/ha/yr, but reduced the estimated volume of eroded bedload from 1.81 to 0.99 m 3/m/ha/yr when compared to uncontrolled urbanization (no wet pond). Alterations to the design of the wet pond, increased volume size and change in orifice diameter, were explored to see if erosional standards could be better met. This study demonstrated the effect of current SCM design standards on stream stability and why geomorphic processes of stream channels should be incorporated in SCM design standards.

Tillinghast, E. D.; Hunt, W. F.; Jennings, G. D.

2011-12-01

131

Barrier erosion control test plan: Gravel mulch, vegetation, and soil water interactions  

SciTech Connect

Soil erosion could reduce the water storage capacity of barriers that have been proposed for the disposal of near-surface waste at the US Department of Energy's Hanford Site. Gravel mixed into the top soil surface may create a self-healing veneer that greatly retards soil loss. However, gravel admixtures may also enhance infiltration of rainwater, suppress plant growth and water extraction, and lead to the leaching of underlying waste. This report describes plans for two experiments that were designed to test hypotheses concerning the interactive effects of surface gravel admixtures, revegetation, and enhanced precipitation on soil water balance and plant abundance. The first experiment is a factorial field plot set up on the site selected as a soil borrow area for the eventual construction of barriers. The treatments, arranged in a a split-split-plot design structure, include two densities of gravel admix, a mixture of native and introduced grasses, and irrigation to simulate a wetter climate. Changes in soil water storage and plant cover are monitored with neutron moisture probes and point intercept sampling, respectively. The second experiment consists of an array of 80 lysimeters containing several different barrier prototypes. Surface treatments are similar to the field-plot experiment. Drainage is collected from a valve at the base of each lysimeter tube, and evapotranspiration is estimated by subtraction. The lysimeters are also designed to be coupled to a whole-plant gas exchange system that will be used to conduct controlled experiments on evapotranspiration for modeling purposes. 56 refs., 6 figs., 8 tabs.

Waugh, W.J.; Link, S.O. (Pacific Northwest Lab., Richland, WA (USA))

1988-07-01

132

Rock-type control on erosion-induced uplift, eastern Swiss Alps  

NASA Astrophysics Data System (ADS)

There is growing evidence that Quaternary rock uplift in parts of the European Alps is a consequence of climate- and erosion-driven isostatic rebound. Contemporary rates of rock uplift U in the Swiss Alps show two distinctive dome-like peak regions that attain ~ 1.6 mm yr - 1 . We focus on the Alpenrhein catchment and its surroundings, where one of these peak regions spatially coincides with widely exposed Cretaceous Bündner schist and lower Tertiary flysch. Field assessments and analyses of hillslope gradient distributions quantitatively demonstrate the low rock-mass strength and high erodibility of these rocks. This is reflected in mean postglacial catchment erosion rates D ~ 4 mm yr - 1 , as opposed to 0.7 mm yr - 1 in more resistant crystalline rocks. Though largely inferred from landslide- and debris-flow prone tributary catchments < 20 km 2, the localised erosion rates in Bündner schist and flysch are among the highest documented for the Alps, and corroborated by historic suspended sediment yields, and thus export, from the region. We further find that the steepness of bedrock rivers, the density of large landslides, and D correlate with the highest values of U. Our observations highlight the possibility that erosion of mechanically weak Bündner schist and flysch enhanced by large landslides may have contributed to regional crustal unloading, and concomitant rock uplift. Irrespective of whether this is betraying a coupling between long-term uplift and erosion modulated by rock type, our findings indicate that long-term (10 3 to 10 4 yr) geomorphic signals contained in bedrock-river steepness, spatial density of large landslides, and postglacial erosion rates strikingly correlate with regional gradients of historic (10 1 yr) rock uplift rates.

Korup, Oliver; Schlunegger, Fritz

2009-02-01

133

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

134

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

135

Chronic erosion in Wissant Bay coast, northern France - Causes and trials of management projects  

NASA Astrophysics Data System (ADS)

Cape Gris Nez to the southwest and Cape Blanc Nez to the northeast limit's Wissant Bay. This extreme northern coast of France, facing the Dover Strait, is one of the most rapidly eroding sector of coast in France. Shoreline retreat has exceeded 250 m in the last fifty years in the central and western parts of the bay, while the eastern sector of the bay is now a zone of accretion, after being a sand-starved zone in the past, when the western sector was either stable or in accretion. The reasons for these changes are still not clear. They seem to involve interactions between a nearshore sand bank and the activity of current gyres related to the projecting headland of Cape Gris Nez, beach rotation processes and human activities, notably past aggregate extraction from the nearshore sand bank which acted hitherto as both a dissipater of incident storm wave energy and as a coastal sand source. The aim of this paper to contribute to the understanding of these long-term changes and investigate the mechanisms of this mildly embayed coast evolution. To this end, 10-years of topographic profile data throughout the bay were analysed and confronted with offshore wave data. This analysis complements a previous analytical effort that determined gross rates of annual shoreline retreat by time slices of several decades from the careful interpretation of long series of ortho-rectified aerial photographs. The overall data suggest chronic sand bleeding from the western sector of the beach and longshore transport to the east, within a framework of what appears to be an ongoing beach rotation process within a dominant longshore sediment transport cell between the headland of Cape Gris Nez and the bold chalk cliffs of Cape Blanc Nez. Retreat of the beach-dune barrier in the western sector of Wissant Bay poses a threat in the coming years as there is a likelihood of storm breaching of the narrow dune barrier. Face to this critical situation, a proper management strategy involving a good understanding and an integrated view of beach and coastal dynamics, as well as defence strategies covering not only the beaches but also the dunes and the nearshore zone must be applied. This can only be effectively done within the framework of the immediate implementation of Integrated Coastal Zone Management.

Sedrati, M.; Anthony, E. J.

2012-04-01

136

Alginate controls heartburn in patients with erosive and nonerosive reflux disease  

PubMed Central

AIM: To evaluate the effect of a novel alginate-based compound, Faringel, in modifying reflux characteristics and controlling symptoms. METHODS: In this prospective, open-label study, 40 patients reporting heartburn and regurgitation with proven reflux disease (i.e., positive impedance-pH test/evidence of erosive esophagitis at upper endoscopy) underwent 2 h impedance-pH testing after eating a refluxogenic meal. They were studied for 1 h under basal conditions and 1 h after taking 10 mL Faringel. In both sessions, measurements were obtained in right lateral and supine decubitus positions. Patients also completed a validated questionnaire consisting of a 2-item 5-point (0-4) Likert scale and a 10-cm visual analogue scale (VAS) in order to evaluate the efficacy of Faringel in symptom relief. Tolerability of the treatment was assessed using a 6-point Likert scale ranging from very good (1) to very poor (6). RESULTS: Faringel decreased significantly (P < 0.001), in both the right lateral and supine decubitus positions, esophageal acid exposure time [median 10 (25th-75th percentil 6-16) vs 5.8 (4-10) and 16 (11-19) vs 7.5 (5-11), respectively] and acid refluxes [5 (3-8) vs 1 (1-1) and 6 (4-8) vs 2 (1-2), respectively], but increased significantly (P < 0.01) the number of nonacid reflux events compared with baseline [2 (1-3) vs 3 (2-5) and 3 (2-4) vs 6 (3-8), respectively]. Percentage of proximal migration decreased in both decubitus positions (60% vs 32% and 64% vs 35%, respectively; P < 0.001). Faringel was significantly effective in controlling heartburn, based on both the Likert scale [3.1 (range 1-4) vs 0.9 (0-2); P < 0.001] and VAS score [7.1 (3-9.8) vs 2 (0.1-4.8); P < 0.001], but it had less success against regurgitation, based on both the Likert scale [2.6 (1-4) vs 2.2 (1-4); P = not significant (NS)] and VAS score [5.6 (2-9.6) vs 3.9 (1-8.8); P = NS]. Overall, the tolerability of Faringel was very good 5 (2-6), with only two patients reporting modest adverse events (i.e., nausea and bloating). CONCLUSION: Our findings demonstrate that Faringel is well-tolerated and effective in reducing heartburn by modifying esophageal acid exposure time, number of acid refluxes and their proximal migration.

Savarino, Edoardo; de Bortoli, Nicola; Zentilin, Patrizia; Martinucci, Irene; Bruzzone, Luca; Furnari, Manuele; Marchi, Santino; Savarino, Vincenzo

2012-01-01

137

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

138

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

139

Holocene activity of an alpine debris-flow catchment: does climate control erosion rate variability?  

NASA Astrophysics Data System (ADS)

The Zielbach catchment is located in the central-eastern Italian Alps. It covers an area of ca. 40 km2 and is characterized by fluvial sediment transport along the main drainage basin, and by the supply of sediment through debris flows, derived from a ca. 10 km2 tributary catchment. A debris-flow database demonstrates that nowadays this latter tributary dominates the sediment budget of the entire Zielbach. In this study, we analyze modern and paleo-erosion rates of the catchment through the application of the cosmogenic nuclides technique. For modern erosion rate, samples of river-born sand were taken from the main river and tributaries along the entire drainage system, while paleo-erosion rates are calculated thanks to cores' samples, which were collected on the alluvial fan and which were likewise dated based on 14C measurements of organic matter. Results obtained from the modern drainage system reveal the spatial erosion rate variability that characterizes the catchment nowadays (values ranging from 2.6 to 0.15 mm/yr). This spatial pattern is characterized by a generally increasing trend of 10Be values where hillslope contributions predominate and by a decreasing concentration trend where sediment has been supplied by debris flows. Results obtained from the cores allow the reconstruction of the Zielbach Holocene evolution and the assignment of the climate role on the temporal erosion rate variability (values ranging between 21 and 0.43 mm/yr). 14C concentrations of organic material collected from the core material indicate a lowermost age of 10'000 yr at ca. 35 m depth. The sedimentary fabric of the deposits indicates that the fan is built up by alternation of alluvial and debris-flow deposits, where the latter ones dominate in volumes. The stratigraphic architecture also infers that alluvial deposits correspond to periods of low activity of the debris-flow catchment. Most important, however, paleo-erosion rates indicate a decreasing trend for the debris-flow activity from ca. 10'000 yr to the present, with values decreasing from ca. 21 to 0.8 mm/yr. During the same time span, the alluvial sediment supplied by the main catchment appears to have been steady, as indicated by a constant basin-averaged denudation rate of 0.45 mm/yr. The comparison of these results with the climatic history of the valley reveals that periods of high activity of the debris flow catchment (associated with higher 10Be-based erosion rates) correspond to periods of a wetter and cooler climate. In particular, the highest value (21 mm/yr) seems to be related to the late glacial phase, which presumably started after the LGM and terminated around 10'000 yr, while a reactivation of the debris-flow activity, with erosion rates around 1.0 mm/yr, corresponds to the Holocene climatic deterioration at ca. 3'500 yr B.P. The alluvial phase of the Zielbach catchment (erosion rate of ca. 0.43 mm/yr), marked by absent or lower debris-flow activity, seems to be related to the Holocene climatic optimum between 8'000 and 4'000 years ago.

Savi, S.; Norton, K. P.; Brardinoni, F.; Akçar, N.; Kubik, P.; Picotti, V.; Schlunegger, F.

2012-12-01

140

Nonlinear PI-control temperature control algorithm for projection lens  

NASA Astrophysics Data System (ADS)

Image quality is the most important performance of optical lithography tool and it is influenced by many factors. Temperature stability of projection lens is one of the main factors. It is difficult to control temperature stability of the projection lens because of its features of big inertia, multi-time-delay and multi-perturbation. Temperature control unit (TCU), which is used to control the projection lens temperature, is required to operate far away from projection lens, otherwise it will increase COO of lithography tool and its vibration will affect the performance of projection lens. So a remote temperature control method is proposed. A two-input and two-output intelligent algorithm is presented to improve convergent rate and steady-state accuracy of the temperature control system for projection lens. Control process is divided into five phases according to the ideal dynamic response curve. A nonlinear PI algorithm is recommended to precisely adjust temperature and an intelligent decision decides the switch of five multi-phases. The experiment results show that +/-0.006°C temperature stability can be realized and the algorithm has advantage of quick convergent rate, strong robustness and self-adaptability. This algorithm has been used in optical lithography tool with 100nm CD and has achieved good temperature stability.

Li, Xiaoping; Nie, Hongfei; Yu, Bin

2007-12-01

141

Climatic Controls on Glacial Erosion and Sediment Transfer: Modeling a South Alaskan Glacial Basin from Range Divide to Shelf Break.  

NASA Astrophysics Data System (ADS)

Understanding the evolution of sediment production and transfer in coastal alpine environments as climate varies is critical to assessing the timing and magnitude of sediment input to the oceans, and to recognizing the potential role of terrestrial mass transfer in modulating ocean geochemical cycles. The sediment load emanating from large wet-based glaciers is orders of magnitude greater than that of comparably sized cold-based ice systems, and considerably greater that of most river drainages. To assess the role of climate in sediment genesis from alpine areas in mid-to high latitudes we, therefore, need to examine the controlling processes under varying climate conditions. We model the evolution of glaciers on the South Alaska coast as they expand from their current retracted positions at the head of fjords to the edge of the continental shelf during cooler periods. The extent of these dynamic ice masses controls the spatial distribution of erosion and the remobilization of massive proglacial deposits over long distances. Glacial quarrying is the most efficient erosional process for temperate glaciers, and subglacial fluvial networks facilitate sediment transfer. Quarrying rate is a function of the frequency and magnitude of water injection at the glacier bed, and of the basal effective pressure, which determines the degree of ice-bed separation and stress concentration on the bedrock. As the amount of rain and melt changes spatially during the course of a glacial cycle, so do quarrying rates. Maximum erosion rates occur near the firn line as it is the location of large pressure transients in an effective pressure range where quarrying is effective. Subglacial melt water channels efficiently excavate previously filled basins and remobilize sediment over the continental slope where the shelf progrades. In this tectonic and climatic setting, the regime on the shelf appears to be slightly aggradational when averaged over a glacial cycle. When the climate cools and glaciers expand, drainage basin-averaged erosion rates tend to decrease along with diminishing free water and an increasing fraction of the bedrock being shielded from erosion by subglacial sediments; on the other hand, sediment outflux from these glaciers increases during these cooling periods. The correlation between climatic cooling and bedrock erosion becomes positive at lower latitudes where the cooling has relatively little negative impact on the efficiency of the hydraulic regime. This work was made possible by a NSF grant.

Merrand, Y.; Hallet, B.

2001-12-01

142

Aspect and soil water repellency controlling water erosion in dry Mediterranean environment  

NASA Astrophysics Data System (ADS)

Soil hydrological response in Mediterranean areas is usually highly complex due to the strong spatial variability. This fact is amplified by the marked seasonality of precipitations, which provokes dramatic changes in vegetation cover and soil properties, such as soil water content or soil water repellency (SWR). The goal of this study is to shed light on the relations between SWR, aspect and vegetation, determining the soil hydrological and erosive response throughout the rainy period in different microenvironments. Erosion plots were set up in the north- and the south-facing hillslope, in shrub-covered as well in inter-shrub patches, and rainfall, runoff, sediments and SWR were monitored. Soils showed water repellency at the end of the dry season in both microenvironments of the north-facing hillslope but only in covered patches of the south-facing one. With the onset of the wet season, SWR disappeared and runoff coefficients decrease dramatically in the north-facing hillslope, revealing the importance of SWR in the hydrological response. In the south-facing hillslope seasonal changes were less important and the hydrological behaviour was mainly modulated by the vegetation pattern. Sediment losses were also affected by SWR and it decreased in the wet season when repellency disappeared. Regarding precipitation, the main factor determining the hydrological and erosive response was rainfall intensity, regardless of the rainfall depth of the event.

Gabarron-Galeote, Miguel A.; Martínez-Murillo, Juan F.; Quesada, Miguel A.; Ruiz-Sinoga, José D.

2014-05-01

143

West Beach, Westport, Connecticut, Sherwood Island State Park. Detailed Project Report and Environmental Assessment.  

National Technical Information Service (NTIS)

Detailed Project Report present results of an analysis of beach erosion problems at Sherwood Island State Park, and investigated several alternative plans of erosion control for West Beach, the Sherwood Island State Park. Recommended beach widening by pla...

1981-01-01

144

Evaluation of the Wind Erosion Prediction System (WEPS) erosion submodel on cropland fields  

Microsoft Academic Search

This study represents part of a project by the Global Change and Terrestrial Ecosystem Soil Erosion Network to validate wind erosion models. Soil loss measurements from 46 storm events from eroding fields in six states were compared to predictions from the Wind Erosion Prediction System (WEPS) erosion submodel. The field data were collected from small (2.5 ha), circular, cropland fields

Lawrence J. Hagen

2004-01-01

145

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

146

Thermal Control System Automation Project (TCSAP)  

NASA Technical Reports Server (NTRS)

Information is given in viewgraph form on the Space Station Freedom (SSF) Thermal Control System Automation Project (TCSAP). Topics covered include the assembly of the External Thermal Control System (ETCS); the ETCS functional schematic; the baseline Fault Detection, Isolation, and Recovery (FDIR), including the development of a knowledge based system (KBS) for application of rule based reasoning to the SSF ETCS; TCSAP software architecture; the High Fidelity Simulator architecture; the TCSAP Runtime Object Database (RODB) data flow; KBS functional architecture and logic flow; TCSAP growth and evolution; and TCSAP relationships.

Boyer, Roger L.

1991-01-01

147

Control research in windpower project 506259 utilization  

NASA Astrophysics Data System (ADS)

Control systems design is analyzed for a windpowered generator with variable velocity. A project for a simplified wind-diesel construction, without a separate bearing was investigated. Yaw motion influence on the lateral motion of the tower was studied. This effect can be attenuated with a better design of the yaw servomotors. The rotor speed was used as out-signal, instead of the acceleration which is proportional to the aerodynamic moment, but the method of computing the acceleration is difficult. Feedback control and mean square errors are outlined.

Ulen, Eskil

1989-01-01

148

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

Cate, H. J. Ten Bruggen

1968-01-01

149

[Optimization of shelterbelt distribution for the gully erosion control of cultivated slope land in rolling hill black soil region of Northeast China].  

PubMed

Shelterbelt system is one of the main components of cultivated slope land in rolling hill black soil region of Northeast China, which plays an important role in the control of gully erosion. Based on the Quickbird high-resolution remote sensing image and the digital elevation model (DEM), and combining with field survey data, this paper analyzed the effects of shelterbelt system in a small watershed of rolling hill black soil region in Heshan Farm of Heilongjiang Province on the control of gully erosion in the cultivated slope land, and put forward an optimized scheme for gully erosion control based on the features of gully erosion in the cultivated slope land and their relations with the distribution of the shelterbelt system. In the study area, the current distribution of the shelterbelt system promoted the occurrence and development of shallow gully and gully directly and indirectly. The proposed scheme for optimizing the distribution of the present shelterbelts included the adjustment of the direction of the shelterbelt perpendicular to the aspect of slope, the enhancement of the maintenance and regeneration of the shelterbelts to reduce the gaps of the shelterbelts, the increase of the shelterbelt number, and the decrease of the distances between shelterbelts. A method for calculating the shelterbelt number and the distances between the shelterbelts was also given. This study could provide scientific basis for the gully erosion control and the shelterbelts programming in the cultivated slope land of rolling hill black soil region. PMID:22803452

Su, Zi-Long; Cui, Ming; Fan, Hao-Ming

2012-04-01

150

Controls and Electronics in the LEBIT Project  

NASA Astrophysics Data System (ADS)

The LEBIT project at the NSCL is an experiment under construction that will accept a high-energy beam from the coupled cyclotron and convert it to a low-energy, low-emittance beam. This low-energy beam will be used in a variety of experiments, including precision mass measurements of exotic nuclei. The experiment contains a gas-stopping cell followed by an ion transport and trapping system. One particular section consists of an ion trap that accumulates incoming ions, cools them, and releases them as ion bunches. Following the buncher is an electrostatic deflector that serves to steer the ions as they leave this trap. Although the control for the deflector is at ground, the deflector needs be raised to an average 2kV potential. Relative to this potential, offsets are applied to the horizontal and vertical steering plates, in order to achieve beam steering. This summer, an electronic board was worked on to accomplish this. The main components of the board include DC/DC converter and high-voltage isolation amplifiers. Because of the complexity of the LEBIT project, all instruments will be controlled through computers. One programming interface currently being used is LabView. Programs have been designed to control the Keithley 2000-20 Multimeter and the Keithley 6514 Electrometer. These instruments will serve to measure voltage and small beam currents.

Janus, Elizabeth

2002-10-01

151

Analysis/control of in-bed tube erosion phenomena in the fluidized bed combustion (FBC) system. Technical progress report No. 3, [April 1, 1993--June 30, 1993  

SciTech Connect

This technical report summarizes the research work performed and progress achieved during the period of during the period of April 1, 1993 to June 30, 1993. The erosion test was conducted in the bench-scale FBC model along with the preparation of the test particles/tube specimens. The effect of the tube-to-distributor (T-to-D) clearance was discussed on the tube specific weight loss for low, medium, and high superficial velocities. Electrostatic impact probes for measuring the particle-surface collision frequency were designed to verify the some of the measurement and to identify the primary erosion points. The erosion models were briefly to understand the phenomena of in-bed erosion. The project has been progressing well. Instrumentation for the erosion-measuring will be continued: to measure the tube weight loss under different operating conditions. Development of the electrostatic probes will be continued and implemented for measuring the particle-tube collision frequency in the bench-scale FBC model.

Lee, Seong W.

1993-07-01

152

In-situ measurements of alloy oxidation/corrosion/erosion using a video camera and proximity sensor with microcomputer control  

NASA Technical Reports Server (NTRS)

Two noncontacting and nondestructive, remotely controlled methods of measuring the progress of oxidation/corrosion/erosion of metal alloys, exposed to flame test conditions, are described. The external diameter of a sample under test in a flame was measured by a video camera width measurement system. An eddy current proximity probe system, for measurements outside of the flame, was also developed and tested. The two techniques were applied to the measurement of the oxidation of 304 stainless steel at 910 C using a Mach 0.3 flame. The eddy current probe system yielded a recession rate of 0.41 mils diameter loss per hour and the video system gave 0.27.

Deadmore, D. L.

1984-01-01

153

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

154

Measurement of the fluorescence of crop residues: A tool for controlling soil erosion  

NASA Technical Reports Server (NTRS)

Management of crop residues, the portion of a crop left in the field after harvest, is an important conservation practice for minimizing soil erosion and for improving water quality. Quantification of crop residue cover is required to evaluate the effectiveness of conservation tillage practices. Methods are needed to quantify residue cover that are rapid, accurate, and objective. The fluorescence of crop residue was found to be a broadband phenomenon with emission maxima at 420 to 495 nm for excitations of 350 to 420 nm. Soils had low intensity broadband emissions over the 400 to 690 nm region for excitations of 300 to 600 nm. The range of relative fluorescence intensities for the crop residues was much greater than the fluorescence observed of the soils. As the crop residues decompose their blue fluorescence values approach the fluorescence of the soil. Fluorescence techniques are concluded to be less ambiguous and better suited for discriminating crop residues and soils than reflectance methods. If properly implemented, fluorescence techniques can be used to quantify, not only crop residue cover, but also photosynthetic efficiency in the field.

Daughtry, C. S. T.; Mcmurtrey, J. E., III; Chappelle, E. W.; Hunter, W. J.

1994-01-01

155

Geomorphic considerations for erosion prediction  

Microsoft Academic Search

Current soil-erosion prediction technology addresses processes of rainsplash, overland-flow sediment transport, and rill\\u000a erosion in small watersheds. The effects of factors determining sediment yield from larger-scale drainage basins, in which\\u000a sediment movement is controlled by the combined small-scale processes and a complex set of channel and other basin-scale sediment-delivery\\u000a processes, such as soil creep, bioturbation, and accelerated erosion due to

W. R. Osterkamp; T. J. Toy

1997-01-01

156

Optimal Land Use Management for Soil Erosion Control by Using an Interval-Parameter Fuzzy Two-Stage Stochastic Programming Approach  

NASA Astrophysics Data System (ADS)

Soil erosion is one of the most serious environmental and public health problems, and such land degradation can be effectively mitigated through performing land use transitions across a watershed. Optimal land use management can thus provide a way to reduce soil erosion while achieving the maximum net benefit. However, optimized land use allocation schemes are not always successful since uncertainties pertaining to soil erosion control are not well presented. This study applied an interval-parameter fuzzy two-stage stochastic programming approach to generate optimal land use planning strategies for soil erosion control based on an inexact optimization framework, in which various uncertainties were reflected. The modeling approach can incorporate predefined soil erosion control policies, and address inherent system uncertainties expressed as discrete intervals, fuzzy sets, and probability distributions. The developed model was demonstrated through a case study in the Xiangxi River watershed, China's Three Gorges Reservoir region. Land use transformations were employed as decision variables, and based on these, the land use change dynamics were yielded for a 15-year planning horizon. Finally, the maximum net economic benefit with an interval value of [1.197, 6.311] × 109 was obtained as well as corresponding land use allocations in the three planning periods. Also, the resulting soil erosion amount was found to be decreased and controlled at a tolerable level over the watershed. Thus, results confirm that the developed model is a useful tool for implementing land use management as not only does it allow local decision makers to optimize land use allocation, but can also help to answer how to accomplish land use changes.

Han, Jing-Cheng; Huang, Guo-He; Zhang, Hua; Li, Zhong

2013-09-01

157

Construction Project Control in Virtual Reality: A Case Study  

Microsoft Academic Search

The construction process is a very complex undertaking. Achieving an effective control for the construction project is very difficult. A Virtual Construction Project Control System (VCPCS) is presented in this study and applied to a practical construction project in Shanghai, China, say, Chia-Tai Mall. VCPCS is the first Virtual Reality (VR) system for a large-scale real construction project in China.

Guo-Cheng Li; Lie-Yun Ding; Jing-Tao Wang

2006-01-01

158

Erosion kinetics of hydrolytically degradable polymers.  

PubMed Central

Degradable polymers are beginning to play an increasing role as materials for environmental and medical applications. Understanding factors that control erosion, such as bond cleavage and the dissolution and diffusion of degradation products, will be critical to the future development of these materials. Erosion kinetics, photomicroscopy, and infrared spectroscopy were used to understand the erosion mechanism of two families of degradable polymers, polyanhydrides and polyesters. Polyanhydrides exhibit behavior more characteristic of surface erosion, whereas the polyesters exhibit bulk erosion patterns. Control of erosion times from a few days to several years can be achieved by a judicious choice of monomer units and bond selection. Images

Tamada, J A; Langer, R

1993-01-01

159

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

160

The role of forest stand density in controlling soil erosion: implications to sediment-related disasters in Japan  

Microsoft Academic Search

The role of forest stand density in con- trolling soil erosion was investigated in Ehime Prefecture, Japan. The main objective was to com- pare soil erosion under different forest conditions including forest type, species composition, and stand density as influenced by thinning operations. Relative yield index (Ry) was used as an indi- cator of stand density to reflect the degree

Bam H. N. Razafindrabe; Shoji Inoue; Tsugio Ezaki; Rajib Shaw

2008-01-01

161

Controlling factors of sheet erosion under degraded grasslands in the sloping lands of KwaZulu-Natal, South Africa  

Microsoft Academic Search

The current increase in the global demand for food and fresh water and the associated land use changes or misuses exacerbate water erosion which has become a major threat to the sustainability of the soil and water resources. Soil erosion by rainfall and runoff is a natural and geologic phenomenon, and one of the most important components of the global

P. Dlamini; C. Orchard; G. Jewitt; S. Lorentz; L. Titshall; V. Chaplot

2011-01-01

162

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

163

Distinguishing between tectonic and lithologic controls on bedrock channel longitudinal profiles using cosmogenic 10Be erosion rates and channel steepness index  

NASA Astrophysics Data System (ADS)

Knickpoints in fluvial channel longitudinal profiles and channel steepness index values derived from digital elevation data can be used to detect tectonic structures and infer spatial patterns of uplift. However, changes in lithologic resistance to channel incision can also influence the morphology of longitudinal profiles. We compare the spatial patterns of both channel steepness index and cosmogenic 10Be-determined erosion rates from four landscapes in Italy, where the geology and tectonics are well constrained, to four theoretical predictions of channel morphologies, which can be interpreted as the result of primarily tectonic or lithologic controls. These data indicate that longitudinal profile forms controlled by unsteady or nonuniform tectonics can be distinguished from those controlled by nonuniform lithologic resistance. In each landscape the distribution of channel steepness index and erosion rates is consistent with model predictions and demonstrates that cosmogenic nuclide methods can be applied to distinguish between these two controlling factors.

Cyr, Andrew J.; Granger, Darryl E.; Olivetti, Valerio; Molin, Paola

2014-03-01

164

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,

165

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...

166

The impact on project success of using technology in modern project planning and control  

Microsoft Academic Search

This paper examines the impact the use of technological tools for project planning and control have on project success. The paper is based on data and conclusions from two earlier international studies involving a wide range of project types and respondents with different stakeholder perspectives. The first study concluded that evaluating project success tended to use rather narrowly focused measures

Svein-Arne Jessen

2011-01-01

167

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

168

Floodplain Assessment for the Proposed Engineered Erosion Controls at TA-72 in Lower Sandia Canyon, Los Alamos National Laboratory  

SciTech Connect

Los Alamos National Laboratory (LANL) is preparing to implement engineering controls in Sandia Canyon at Technical Area (TA) 72. Los Alamos National Security (LANS) biologists conducted a floodplain determination and this project is located within a 100-year floodplain. The proposed project is to rehabilitate the degraded channel in lower Sandia Canyon where it crosses through the outdoor firing range at TA-72 to limit the loss of sediment and dissipate floodwater leaving LANL property (Figure 1). The proposed construction of these engineered controls is part of the New Mexico Environment Department's (NMED) approved LANL Individual Storm Water Permit. The purpose of this project is to install storm water controls at Sandia Watershed Site Monitoring Area 6 (S-SMA-6). Storm water controls will be designed and installed to meet the requirements of NPDES Permit No. NM0030759, commonly referred to as the LANL Individual Storm Water Permit (IP). The storm water control measures address storm water mitigation for the area within the boundary of Area of Concern (AOC) 72-001. This action meets the requirements of the IP for S-SMA-6 for storm water controls by a combination of: preventing exposure of upstream storm water and storm water generated within the channel to the AOC and totally retaining storm water falling outside the channel but within the AOC.

Hathcock, Charles D. [Los Alamos National Laboratory

2012-08-27

169

Beach Erosion  

NASA Technical Reports Server (NTRS)

Two miles of beach at Cape Canaveral eroded by construction of a port and jetties was recently restored. Such work in harbors of many cities often disrupts normal flow of sand for many miles along coasts. Brevard County, FL residents now enjoy a 400 ft. wide public beach in an area in imminent danger of destructive erosion just a year previously. Before and after aerial photos show how more than two miles of beach were rebuilt with 2.7 million cubic yards of sand helping abate the erosion problem caused by construction of jetties. NASA volunteered its remote-sensing technology and instrumented aircraft to provide low-altitude color infrared photography about every three months since 1972.

1976-01-01

170

Influence of inhomogeneous static magnetic field-exposure on patients with erosive gastritis: a randomized, self- and placebo-controlled, double-blind, single centre, pilot study.  

PubMed

This pilot study was devoted to the effect of static magnetic field (SMF)-exposure on erosive gastritis. The randomized, self- and placebo-controlled, double-blind, pilot study included 16 patients of the 2nd Department of Internal Medicine, Semmelweis University diagnosed with erosive gastritis. The instrumental analysis followed a qualitative (pre-intervention) assessment of the symptoms by the patient: lower heartburn (in the ventricle), upper heartburn (in the oesophagus), epigastric pain, regurgitation, bloating and dry cough. Medical diagnosis included a double-line upper panendoscopy followed by 30 min local inhomogeneous SMF-exposure intervention at the lower sternal region over the stomach with peak-to-peak magnetic induction of 3 mT and 30 mT m(-1) gradient at the target site. A qualitative (post-intervention) assessment of the same symptoms closed the examination. Sham- or SMF-exposure was used in a double-blind manner. The authors succeeded in justifying the clinically and statistically significant beneficial effect of the SMF- over sham-exposure on the symptoms of erosive gastritis, the average effect of inhibition was 56% by p = 0.001, n = 42 + 96. This pilot study was aimed to encourage gastroenterologists to test local, inhomogeneous SMF-exposure on erosive gastritis patients, so this intervention may become an evidence-based alternative or complementary method in the clinical use especially in cases when conventional therapy options are contraindicated. PMID:25008086

Juhász, Márk; Nagy, Viktor L; Székely, Hajnal; Kocsis, Dorottya; Tulassay, Zsolt; László, János F

2014-09-01

171

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

172

Hail Control. Operative and Scientific Research Project.  

National Technical Information Service (NTIS)

Contents: Physical basis of artificial modification of clouds; Development of hail control in the world; Characteristics of the hail control system developed in the U.S.S.R.; Development of hail control in Yugoslavia; Professional-scientific definition of...

D. Radinovic

1972-01-01

173

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

174

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

175

Evolutionary game analysis on quality control of construction project  

Microsoft Academic Search

In order to analyze the effect of different behaviors of quality control department and construction contractor on the construction project quality management model, an evolutionary game model of construction project quality management was established. In this model, the effect and position of social responsibility and fines were carefully discussed and the dynamic evolutionary procedure and stable equilibrium of construction project

Lian-fa Ruan; Fu-ming Chen

2011-01-01

176

Mapping of soil erosion using remotely sensed data in Zombodze South, Swaziland  

NASA Astrophysics Data System (ADS)

Zombodze South is situated in the southern part of Swaziland. It has visible signs of soil erosion. However like many parts of the country, soil erosion has not been mapped. The area lacks soil conservation measures. The objective of the study was to map the spatial distribution of soil erosion, and to determine the perception of community members on soil erosion problems. IDRISI for Windows was used to produce 20 clusters from Landsat ETM data for January 1999. The clusters were allocated to five land cover classes based on a combination of use of “scatterplots” and NDVI values. Gullies were identified on digital aerial photos of the area, and digitized. Other land features such as settlements, roads and rivers were also digitized. A structured questionnaire was administered to 40 homesteads that were randomly selected from the 234 homesteads in the community to collect information on perception of communities on soil erosion, as well as their involvement in controlling soil erosion. About 4% of the area was eroded, with another 38% having very sparse vegetation cover. Gully erosion was prevalent in the southern part of the area. The limited soil erosion conservation measures in the area were undertaken by local school children as part of their school projects. The control measures suggested by members of the community included planting trees and grasses along the gullies, fencing of gullies and construction of check dams.

Manyatsi, Absalom M.; Ntshangase, Nomndeni

177

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

178

A methodology for project control through risk analysis: the case of a pipeline project  

Microsoft Academic Search

Projects exposed to uncertainties can be effectively controlled with the application of risk analysis during the planning stages. The Analytic Hierarchy Process (AHP), can be used to analyse risks associated with such projects. The results from risk analysis along with activity analysis are combined to develop a logical contingency allowance for the project through the application of probability theory. Effective

S. O. Ogunlana; M. T. Tabucanon; P. Dey

1993-01-01

179

Internet-based database management system for project control  

Microsoft Academic Search

Purpose – The objective of this paper is to develop an efficient project management system to track and control construction activities for contractors and\\/or project managers. Design\\/methodology\\/approach – The work package model is utilized to break down project data into activities and work tasks. The data structure of a project is represented using the entities-relationship methodology. A relational database stores

Ji Li; Osama Moselhi; Sabah Alkass

2006-01-01

180

High performance heuristic algorithm for controlling stochastic network projects  

Microsoft Academic Search

An activity-on-arc network project of PERT type with random activity durations is considered. The progress of the project cannot be inspected and measured continuously, but only at preset inspection points. An on-line control model has to determine both inspection points and control actions to be introduced at those points to alter the progress of the project in the desired direction.

Dimitri Golenko-Ginzburg; Aharon Gonik

1998-01-01

181

How to Maintain Project Control via Checkpoints.  

ERIC Educational Resources Information Center

Provides an outline of items for consideration when planning construction projects for new educational facilities. Establishing checkpoints, calendaring events, delineating responsibilities, and developing a checklist and timeline to follow during planning and construction as well as a close-out audit help ensure success. Includes a copy of a…

Hargraves, Darroll; Vanwechel, Pamela

1987-01-01

182

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

183

The future of olive groves on sloping land and ex-ante assessment of cross compliance for erosion control  

Microsoft Academic Search

Under the past Common Agricultural Policy (CAP) olive oil subsidy regime, farmers were eligible for subsidies on the basis of the amount of olive oil they produced. This led to an intensification of production, particularly on flat land, and had in most cases negative environmental effects, such as more soil erosion on sloping land and more pollution. With the decoupling

Jan de Graaff; Filomena Duarte; Luuk Fleskens; Tomás de Figueiredo

2010-01-01

184

Soil rehabilitation and erosion control through agro-ecological practices on Reunion Island (French Overseas Territory, Indian Ocean)  

Microsoft Academic Search

On the western slopes of Reunion Island, the trends in cropping systems for perfume pelargonium are causing serious erosion problems. This paper reviews the causes of these trends, presents the consequences of this deterioration, and assesses the agro-ecological solutions by means of cover plants and hedging with agroforest species. Firstly, the short term effects of cover plants (Lotus uliginosus, Pennisetum

Sylvain Perret; Roger Michellon; Johnny Boyer; Jacques Tassin

1996-01-01

185

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

186

Corrective measures technology for shallow land burial at arid sites: field studies of biointrusion barriers and erosion control  

Microsoft Academic Search

The field research program involving corrective measures technologies for arid shallow land burial (SLB) sites is described. Results of field testing of a biointrusion barrier installed at a close-out waste disposal site (Area B) at Los Alamos are presented. Soil erosion and infiltration of water into a simulated trench cap with various surface treatments were measured, and the interaction between

J. W. Nyhan; T. E. Hakonson; E. A. Lopez

1986-01-01

187

A method to measure clinical erosion: the effect of orange juice consumption on erosion of enamel  

Microsoft Academic Search

Objective: Acidic soft drinks are frequently implicated in dental erosion, but there are limited supporting data. Research is problematic due to the insidious nature of erosion and accuracy in assessing tissue loss. The aim of this study was to develop and validate, using a negative control, a model to accurately measure erosion in situ due to a single aetiological agent

N. X. West; A. Maxwell; J. A. Hughes; D. M. Parker; R. G. Newcombe; M. Addy

1998-01-01

188

Guidance and Control Software Project Data - Volume 1: Planning Documents  

NASA Technical Reports Server (NTRS)

The Guidance and Control Software (GCS) project was the last in a series of software reliability studies conducted at Langley Research Center between 1977 and 1994. The technical results of the GCS project were recorded after the experiment was completed. Some of the support documentation produced as part of the experiment, however, is serving an unexpected role far beyond its original project context. Some of the software used as part of the GCS project was developed to conform to the RTCA/DO-178B software standard, "Software Considerations in Airborne Systems and Equipment Certification," used in the civil aviation industry. That standard requires extensive documentation throughout the software development life cycle, including plans, software requirements, design and source code, verification cases and results, and configuration management and quality control data. The project documentation that includes this information is open for public scrutiny without the legal or safety implications associated with comparable data from an avionics manufacturer. This public availability has afforded an opportunity to use the GCS project documents for DO-178B training. This report provides a brief overview of the GCS project, describes the 4-volume set of documents and the role they are playing in training, and includes the planning documents from the GCS project. Volume 1 contains five appendices: A. Plan for Software Aspects of Certification for the Guidance and Control Software Project; B. Software Development Standards for the Guidance and Control Software Project; C. Software Verification Plan for the Guidance and Control Software Project; D. Software Configuration Management Plan for the Guidance and Control Software Project; and E. Software Quality Assurance Activities.

Hayhurst, Kelly J. (Editor)

2008-01-01

189

Large Scale Predictions of Potential Post-fire Erosion  

NASA Astrophysics Data System (ADS)

High-severity wildfires are of increasing concern because of their potential for initiating flash floods and surface erosion, degrading water quality, and reducing reservoir capacity. In many areas fire suppression has increased fuel accumulations and hence the potential for high-severity wildfires. Land management agencies are undertaking programs to reduce fuel loadings and the associated risk of high-severity wildfires, but the areas needing treatment greatly exceed the available funding. It is therefore necessary to determine which areas should have a higher priority for such treatments. Similarly, when wildfires do occur there is an immediate need to determine which areas should have the highest priority for post-fire rehabilitation treatments. One criterion for allocating treatments is the potential risk of post-fire erosion, but to be effective this assessment needs to be carried out at a broad scale. This paper presents a procedure and initial results for predicting spatially-explicit, post-fire erosion risks at the hillslope scale for forest and shrub lands across the western U.S. Our approach utilizes existing physical models and datasets in a GIS framework. The model for predicting erosion is GeoWEPP, the Geographical interface for the Water Erosion Prediction Project (WEPP). The primary inputs for GeoWEPP include climate, topography, soils, and land cover/land use. Daily climate inputs were generated with Cligen, which is a stochastic weather generator distributed with WEPP. A 30-m digital elevation model, STATSGO-derived soils data, and vegetation cover were obtained from the U.S. Forest Service's LANDFIRE project. Since recent research has shown that percent ground cover is a dominant control on post-fire erosion rates, we generated a spatially-explicit map of post-fire ground cover by first using historic weather data to determine the 1000-hr fuel moisture values when fuel conditions were at 98-100% ERC (Energy Released Component). These fuel moisture values were fed into FOFEM (First Order Fire Effects Model) to obtain spatially-explicit predictions of percent ground cover, and this provided the additional land cover/land use information needed by GeoWEPP. The predicted erosion rates are comparable to measured values in the Colorado Front Range, but are much too high for the higher rainfall areas along the Pacific Coast. This pattern indicates that precipitation is having a pre-dominant effect on predicted post-fire erosion rates, especially in areas that are projected to burn at low severity. Hence the predicted erosion rates will be most useful in relative terms at the local and possibly regional scale, while comparisons between regions may be of more limited validity.

Miller, M. E.; MacDonald, L. H.

2005-12-01

190

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

191

Guidance and Control Software Project Data - Volume 2: Development Documents  

NASA Technical Reports Server (NTRS)

The Guidance and Control Software (GCS) project was the last in a series of software reliability studies conducted at Langley Research Center between 1977 and 1994. The technical results of the GCS project were recorded after the experiment was completed. Some of the support documentation produced as part of the experiment, however, is serving an unexpected role far beyond its original project context. Some of the software used as part of the GCS project was developed to conform to the RTCA/DO-178B software standard, "Software Considerations in Airborne Systems and Equipment Certification," used in the civil aviation industry. That standard requires extensive documentation throughout the software development life cycle, including plans, software requirements, design and source code, verification cases and results, and configuration management and quality control data. The project documentation that includes this information is open for public scrutiny without the legal or safety implications associated with comparable data from an avionics manufacturer. This public availability has afforded an opportunity to use the GCS project documents for DO-178B training. This report provides a brief overview of the GCS project, describes the 4-volume set of documents and the role they are playing in training, and includes the development documents from the GCS project. Volume 2 contains three appendices: A. Guidance and Control Software Development Specification; B. Design Description for the Pluto Implementation of the Guidance and Control Software; and C. Source Code for the Pluto Implementation of the Guidance and Control Software

Hayhurst, Kelly J. (Editor)

2008-01-01

192

On the number of control sets on projective spaces  

Microsoft Academic Search

The purpose of this paper is to provide an upper bound for the number of control sets for linear semigroups acting on a projective space RPd?1. These semigroups and control sets were studied by Colonius and Kliemann (1993) who proved that there are at most d control sets. Here we apply the results of San Martin and Tonelli (1995) about

Carlos JoséBraga Barros; Luiz A. B. San Martin

1996-01-01

193

Design of decentralized multivariable excitation controllers in multimachine power systems by projective controls  

SciTech Connect

A methodology for the design of decentralized multivariable excitation and controllers in multimachine power systems is developed using projective controls. The existing methodology, is extended to permit the coordinated design of AVR and PSS controllers in power systems.

Arnautovic, D.; Medanic, J.

1987-12-01

194

Late Quaternary glacial relief evolution and fracture-density control on erosion revealed by low-temperature thermochronometry and remote sensing (Granite Range, Alaska)  

NASA Astrophysics Data System (ADS)

Long-term erosion and topographic evolution of mountain belts arise from complex coupling between tectonics, climate and surface processes. The Granite Range (Wrangell-St Elias National Park, Alaska) presents an ideal setting to study such interactions. Its alpine landscape, preserving typical glacial features (U-shaped valleys, cirques), appears highly smoothed in the west, and progressively more rugged towards the east. In the field, this is evidenced by minor and only localized faulting of massive bedrock (granite and paragneiss) in the west, while the eastern part shows highly fractured bedrock (penetrative faults, fault gouges). Remote-sensing analysis confirms that fracture density is much higher towards east, and also reveals high post-glacial incision only in areas associated with high fracture density. To quantify our morphometric observations, we sampled four elevation profiles (~15 samples in total) over an 80-km East-West transect for low-temperature thermochrometry. Apatite (U-Th-Sm)/He dating provides ages between ~10 and 30 Ma, in agreement with published data, and shows apparent low long-term exhumation rates (~0.05-0.1 km/Ma). Preliminary 4He/3He thermochronometry data reveal a more complex exhumation history, with a significant increase since ~6-5 Ma which can be related to either onset of glaciations in Alaska or a major change in tectonic activity occurring at that period. Further data collected within the Granite Range will help to decipher the origin of this late-Miocene acceleration in exhumation. We also performed luminescence thermochronometry measured on feldspar separates from bedrock samples. Our results show a strong East-West gradient in samples saturation ratio. Apparent ages vary from ~250 ka in the western part of the range, towards younger ages of ~30 ka in the east. This pattern reveals spatially variable erosion rates during the late Quaternary associated with a major fracture-density control on erosion, and further supports the notion of amplified erosion due to intense glacial/periglacial activity. This presents evidence for a bimodal relief evolution and structural control on erosion in a glacially-active mountain range, and demonstrates the potential of luminescence thermochronometry in resolving topographic evolution and surface processes over 100-ka timescales enclosing high-frequency climate modulations (e.g., glacial-interglacial oscillations).

Valla, Pierre; Champagnac, Jean-Daniel; Herman, Frédéric; Lowick, Sally; Guralnik, Benny; Shuster, David; Fellin, Giuditta

2013-04-01

195

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

196

Statistical Process Control. A Summary. FEU/PICKUP Project Report.  

ERIC Educational Resources Information Center

A project was conducted to develop a curriculum and training materials to be used in training industrial operatives in statistical process control (SPC) techniques. During the first phase of the project, questionnaires were sent to 685 companies (215 of which responded) to determine where SPC was being used, what type of SPC firms needed, and how…

Owen, M.; Clark, I.

197

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...

198

North American Joint Positive Train Control (NAJPTC) Project. Research Results.  

National Technical Information Service (NTIS)

The North American Joint Positive Train Control (NAJPTC), was an ambitious project to develop, test, and demonstrate PTC capabilities, including flexible block operations, interoperability, and advance activation of highway grade crossing devices, in a co...

2009-01-01

199

Interactive Control of Nonlinear Projection for Complex Animated Scenes  

Microsoft Academic Search

Abstract Interactive Control of Nonlinear Projection for Complex Animated Scenes Patrick Coleman Master of Science Graduate Department of Computer Science University of Toronto 2004 Linear perspective has long been at the foundation of most graphics systems. While

Patrick Coleman

2004-01-01

200

Direct Digital Control System Energy Projects.  

National Technical Information Service (NTIS)

Direct digital control (DDC) of heating, ventilating, and air-conditioning (HVAC) equipment has become a popular building retrofit. However, converting a building to DDC will not always save energy. In fact, it is not uncommon for energy consumption to in...

G. Sittel

1997-01-01

201

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

202

Analysing, quantifying and modelling soil erosion on steep hillslopes in different climatic areas using LiDAR and SFM DEMs  

NASA Astrophysics Data System (ADS)

Soil erosion is a worldwide well known problem and has therefore been subject to various scientific studies, especially on agricultural areas. However soil erosion on steep hillslopes in mountainous drainage basins can be a threat to human infrastructure as it supplies material, e.g. for debris flows to torrents. The study presented here aims to analyse, quantify and model soil erosion on (very) steep hillslopes free of vegetation in different climatic areas ranging from South Germany to Central Italy. Multitemporal digital elevation models were acquired with terrestrial laserscanning and from terrestrial and aerial structure from motion-based imagery. Analysis of erosion is mainly based on slope wash and rill erosion during summer months as well as erosion through freezing and melting processes during winter months in catchments of the Bavarian Alps. Erosional processes in the Mediterranean are mainly controlled by different precipitation regimes throughout the year. Annual erosion and accumulation rates are quantified and used for modelling purposes. First results of the presented project show, that the amount of material eroded is mainly controlled by the size of the sediment contributing area. However there are also other controlling factors, such as slope angle, slope length and vegetation cover which are investigated within this project.

Neugirg, Fabian; Haas, Florian; Kaiser, Andreas; Schmidt, Jürgen; Becht, Michael

2014-05-01

203

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.

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

2014-01-01

204

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

205

Reactive Accelerated Cluster Erosion (race)  

NASA Astrophysics Data System (ADS)

Beams of ionized clusters of some thousand atoms are accelerated to about 100-keV kinetic energy to be used for area selective surface erosion. Mask projective cluster-impact lithography allows surface structuring in the submicron regime. Chemical reactions between the cluster and the target material may provide volatile reaction products facilitating ejecta removal. The reactive accelerated cluster erosion (RACE) process is applied to metals like copper and gold, to semiconductors such as silicon, and to insulators like glass, quartz, or sapphire, giving very smooth eroded surface and steep sidewalls.

Gspann, Jürgen

206

Road Map for Future Controller Interface Device Projects.  

National Technical Information Service (NTIS)

The Controller Interface Device (CID) has been a major focus of the NIATT Center for Traffic Operation and Controls for the past several years, leading to the commercial release of the CID II. Several projects related to further CID development have since...

B. K. Johnson Z. Li T. R. Cuffn

2005-01-01

207

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

208

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

209

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 (LSS) project offices. The first two elements, Orion and Altair, are manned space vehicles while the third element is broader and includes several subelements 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 approximately 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.

2009-01-01

210

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 subelements 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. The current paper will provide an update to a similar overview paper published at last year s International Conference on Environmental Systems (ICES).

Stephan, Ryan A.

2009-01-01

211

76 FR 7807 - Thorne Bay Ranger District; Alaska; Big Thorne Project Environmental Impact Statement  

Federal Register 2010, 2011, 2012, 2013

...will consider the cumulative effects of the timber harvest...opportunities. The effects of the reasonably...bridges, erosion control, vegetation removal...The potential effects of the project...Spill Prevention Control and...

2011-02-11

212

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

213

Greenridge MultiPollutant Control Project Preliminary Public Design Report  

Microsoft Academic Search

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, NO, Hg, acid gases (SO, HCl, and HF), and particulate matter from smaller coal-fired electrical generating units (EGUs). The multi-pollutant control system includes

Daniel P. Connell

2009-01-01

214

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

215

33 CFR 203.85 - Rehabilitation of Federal flood control projects.  

Code of Federal Regulations, 2013 CFR

... false Rehabilitation of Federal flood control projects. 203.85 Section...203.85 Rehabilitation of Federal flood control projects. Some sponsors of Federal flood control projects are not required...

2013-07-01

216

Building the evidence base for effective tobacco control policies: the International Tobacco Control Policy Evaluation Project (the ITC Project).  

PubMed

The Framework Convention on Tobacco Control (FCTC) is a seminal event in tobacco control and in global health. Scientific evidence guided the creation of the FCTC, and as the treaty moves into its implementation phase, scientific evidence can be used to guide the formulation of evidence-based tobacco control policies. The International Tobacco Control Policy Evaluation Project (ITC Project) is a transdisciplinary international collaboration of tobacco control researchers who have created research studies to evaluate and understand the psychosocial and behavioural impact of FCTC policies as they are implemented in participating ITC countries, which together are inhabited by over 45% of the world's smokers. This introduction to the ITC Project supplement of Tobacco Control presents a brief outline of the ITC Project, including a summary of key findings to date. The overall conceptual model and methodology of the ITC Project--involving representative national cohort surveys created from a common conceptual model, with common methods and measures across countries--may hold promise as a useful paradigm in efforts to evaluate and understand the impact of population-based interventions in other important domains of health, such as obesity. PMID:16754940

Fong, G T; Cummings, K M; Shopland, D R

2006-06-01

217

Shoreline Erosion Processes: Orwell Lake, Minnesota.  

National Technical Information Service (NTIS)

Orwell Lake, in west-central Minnesota, is a flood-control, water-management reservoir first impounded in 1953. Subsequent erosion of the shoreline and a lack of knowledge of slope erosion processes in this region prompted this study to identify and quant...

J. R. Reid

1984-01-01

218

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...

219

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

220

A Participatory and Inter-institutional Project to Enhance the Sustainability of Cassava Production in Thailand, Vietnam and China: Its Impact on Soil Erosion and Farmers' Income1  

Microsoft Academic Search

Farmers in Asia like to grow cassava because the crop will tolerate long dry periods and poor soils, and will produce reasonable yields with little inputs. Most farmers realize, however, that cassava production on slopes can cause severe erosion, while production without fertilizer inputs may lead to a decline in soil productivity. Research has shown that cassava yields can be

Reinhardt H. Howeler

221

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

222

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

223

Instrument remote control project at TNG: SARG implementation  

NASA Astrophysics Data System (ADS)

The high resolution spectrograph at TNG (SARG), mounted at the telescope in 2000, is based on the 'first generation CCD controller, transputers and VME real time computer that control the instrument and the detectors. The evolution of the CCD controller, with high performance in speed acquisition and transfer rate, has changed the architecture of the instrument control. Due to the high performances of modern LAN, it has become possible to have direct access to CCD controller and instruments features. The architecture is based on a remote system, connected to a local system through standard network facilities and communicating with it using an XML-like syntax. The remote system receives from the local system commands and, in turn, sends back telemetry and images. This control system will be tested for the first time with the SARG spectrograph, in the framework of the Instruments remote control project at the Telescopio Nazionale Galileo (TNG).

Cosentino, Rosario; Bruno, Pietro; Gonzalez, Manuel; Huertas, Manuel; Scuderi, Salvatore

2004-09-01

224

Improving soil bioengineering techniques to control erosion and sedimentation within the context of torrential Mediterranean climate: a French-Canadian experience  

NASA Astrophysics Data System (ADS)

On marly eroded terrains of the French Southern Alps, many researches are undertaken in order to better understand the role of vegetation and bioengineering works on erosion and sedimentation control. To this view, the eroded marly gullies of the French Southern Alps are an experimental design where an original French strategy of rehabilitation, developed by scientists from Irstea (ex-Cemagref), has been tested since 2002. It is comprised of the construction of bioengineering works, namely of "brush layers and brush mats of cuttings on deadwood microdams", and implements the use of willow cuttings (Salix purpurea and S. incana). The main objective of these works is to sustainably trap and retain marly sediment, by checking their performance (growth and survival of the cuttings, sediment trapping) in a mountainous and Mediterranean climate. In Canada, several private companies have developed their own knowledge and expertise in the conception and building of bioengineering works for erosion control, especially in the context of hilly and mountainous landscapes and climates. Therefore, it was decided to use the competence and expertise of Terra Erosion Control Ltd., a Canadian company, in the French torrential Mediterranean climate. Ten modalities were tested, the aims being to develop and/or to modify existing designs of current techniques, to experiment with other live cuttings (Populus nigra) and rooted species (Alnus spp. and Hippophae spp.), to evaluate and compare the potential use of different organic soil amendments in order to increase beneficial soil microorganisms and finally, to evaluate the potential use of specialized tools and equipment in order to increase the efficiency of the installation for vegetation establishment and sediment trapping, while decreasing the implementation costs. The experimental design was installed in March 2011 and the early observations in Spring 2012 showed that: 1/ most of the cuttings and the plants resisted to burial and to drought conditions; in particular, the structures using wooden boards instead of locally harvested logs appeared to be holding up well; 2/ designs of current techniques with vertical cuttings were better for resprouting and sediment trapping; 3/ 0.8m live cuttings of Populus nigra may represent an alternative to Salix spp., but resprout appeared lower; 4/ it was not possible to evaluate the performance of rooted species (Alnus spp. and Hippophae spp.); therefore more experiment is needed, especially with longer plants; 5/ organic soil amendments may increase vegetation development (BRF > fertilizer > compost > mixes). By comparing the results with similar sites used as benchmarks, installed since 2002, further observations in the spring of 2013 will allow us to evaluate the efficiency of the different modalities to improve vegetation establishment and sediment trapping.

Rey, Freddy; Louis, Séverine; Burylo, Mélanie; Raymond, Pierre

2013-04-01

225

Erosion resistant coatings  

NASA Technical Reports Server (NTRS)

Apparatus for measuring the resistance of materials to erosion is examined and a scheme for standardization of the test parameters is described. Current materials being used for protecting aircraft parts from erosion are surveyed, their chief characteristics being given. The superior properties of urethane coatings are pointed out. The complete cycle for painting areas subject to erosion is described.

Falco, L.; Cushini, A.

1981-01-01

226

Wind Erosion Research Unit  

NSDL National Science Digital Library

This website provides a synopsis of wind erosion, which can threaten the sustainability of natural resources. The USDA Wind Erosion Unit provides maps of areas at risk for wind erosion and drought, as well as a drought monitor and models. There is also an archive of material related to the Dust Bowl.

Service, United S.; University, Kansas S.

227

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...

228

Anthropogenic Effects on Erosion  

NSDL National Science Digital Library

This exercise focuses on anthropogenic effects on erosion. It could be run as a single lab or as a series of in-class exercises or problem sets. We discussed an article by Hooke and used it as a launching pad for a discussion of back of the envelope calculations. Students then estimate the volume moved by mountain-top removal and how long it might take a river to mobilize that sediment. They estimate the cost for beach nourishment along Florida beaches. They estimate the contribution of local construction projects and road gravel to stream sediment loads. This activity gives students a chance to formulate a problem, make simple measurements, estimate unknowns, and calculate volumes, rates, and costs of various human earth-moving activities. Designed for a geomorphology course Addresses student fear of quantitative aspect and/or inadequate quantitative skills Uses geomorphology to solve problems in other fields

Gran, Karen

229

Multivariate statistical process control based on multiway locality preserving projections  

Microsoft Academic Search

An approach for multivariate statistical process control based on multiway locality preserving projections (LPP) is presented. The recently developed LPP is a linear dimensionality reduction technique for preserving the neighborhood structure of the data set. It is characterized by capturing the intrinsic structure of the observed data and finding more meaningful low-dimensional information hidden in the high-dimensional observations compared with

Kunlun Hu; Jingqi Yuan

2008-01-01

230

Control Aspects of the Tacoma Superconducting Magnetic Energy Storage Project  

Microsoft Academic Search

On February 16, 1983, a 10 MW\\/30 MJ superconducting magnetic energy storage unit was energized at the Bonneville Power Administration (BPA) substation in Tacoma, Washington. The unit was retired a year later, after extensive tests directed toward its experimental use as a small-signal stabilizer for the Pacific AC Intertie. This paper addresses the control aspects of the project. These include

J. F. Hauer; H. J. Boenig

1987-01-01

231

Integrated Quality Control Measurement Project. Findings and Corrective Actions.  

ERIC Educational Resources Information Center

The Integrated Quality Control Measurement Project (IQCMP) of the U.S. Department of Education measured the quality of awards distributed during the 1988-89 award year under the three major Title IV programs: the Pell Grant program, the Campus-Based programs, and the Stafford Loan program, in order to evaluate and improve the quality of the…

Price Waterhouse and Co., New York, NY.

232

Intelligent control of autonomous underwater vehicles: the Orca project  

Microsoft Academic Search

Establishing a useful presence in the ocean is becoming increasingly important to science, industry, and the military, yet the undersea environment is hostile to human presence. Autonomous underwater vehicles (AUVs) offer a solution. Before widespread use of AUVs is practical, however, mechanisms for intelligent control must be developed. In this paper, we report on the Orca project, which has the

Roy M. Turner

1995-01-01

233

Control design deficiencies in HUD solar demonstration projects  

SciTech Connect

The Department of Housing and Urban Devlopment (HUD) residential solar heating and cooling demonstration program provided funding support for over 600 solar projects. These projects provide the largest single data base of solar heating and cooling experience now available. These data suggest that controls were problematic in many of the active and passive heating and domestic and domestic hot water systems in the program. This paper will assess the active system modes of operation and the control components as to their ability to perform as intended. A large number of systems in the demonstration program experienced control problems during testing, checkout, and operation (there were 238 reported control problems involving 192 systems). Frequently, trouble-shooting site visitors found control problems had disabled the whole system or caused a portion of the system to malfunction. The consequences are not as significant on the more carefully designed systems (i.e., the auxiliary still functions) but, on systems with inappropriately designed solar-auxiliary interfaces, the homeowners often were without adequate heat. The most common control problems involved excessive modes in system and, therefore, control design; errors in sensor set points, location, or installation; and poorly engineered or installed wiring to and from controller panels.

Freeborne, W.E.

1985-01-01

234

CE IGCC repowering project: Controls & instrumentation. Topical report, June 1993  

SciTech Connect

The IGCC Control System is used to provide operator interface and controls for manual and auto operation of the IGCC Repowering Project Located at Springfield, Illinois. A Distributed Control System (DCS) is provided for analog (process control) loop functions and to provide the operator interface. A Data Acquisition System (DAS) is provided for gathering performance data and optimization. Programmable Logic Controllers will be provided for the following digital control systems: (a) GSSS (Gasifier Supervisory Safety System) including pulverized coal handling and char handling; (b) Coal Pulverization System; (c) HRSG (Heat Recovery Steam Generation); (d) Hot Gas Cleanup System; (e) Steam Turbine; and (f) Combined Cycle Operation. In general all systems are provided for auto/manual cascade operation; upstream equipment is interlocked to be proven in service operation and/or valve position before downstream equipment may operate.

Not Available

1993-12-01

235

[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

236

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

237

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

238

Erosion database interface (EDI): a computer program for georeferenced application of erosion prediction models  

NASA Astrophysics Data System (ADS)

The multidisciplinary approach of soil erosion research often requires erosion to be treated as spatial georeferenced information. This condition is essential so as to be compatible with information analyzed via Geographic Information Systems (GIS). The original versions of important soil erosion prediction models such as the Universal Soil Loss Equation (USLE) and Water Erosion Prediction Project (WEPP) do not operate on a georeferenced basis. The Erosion Database Interface (EDI) is a computer program for georeferenced application of USLE and WEPP. EDI uses, as input, a text format database with points defined by coordinates ( x, y and z) representing hillslopes, each point associated to soil type and land use. Such input data can be provided by different methods. Exclusive field work with ordinary topographic equipment and GIS procedures are examples of methods that can be used for this purpose. Flexibility in the methods adopted for providing input data is an important prerequisite for erosion prediction in tropical and developing regions, where soil erosion is a major concern and the availability of digital data is usually restricted. Hillslopes for EDI were defined as straight line segments beginning at the upper slope and ending down at runoff output. This restricts EDI as a complete erosion-prediction method for areas where runoff deflecting features predominate or where channel or gully erosion is to be considered. As output, EDI provides georeferenced soil erosion values in another text format database. This database can be used directly for statistical or geostatistical analysis or imported into a GIS for further processing. A practical example representative of a sugarcane-growing area located at the southeastern part of Brazil is used to illustrate EDI's performance. In this example, soil erosion maps were produced from GIS data using EDI as interface for erosion calculations for WEPP and USLE.

Ranieri, Simone Beatriz Lima; de Jong van Lier, Quirijn; Sparovek, Gerd; Flanagan, Dennis C.

2002-06-01

239

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

240

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

241

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

242

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

243

Evaluation of the serum zinc level in erosive and non-erosive oral lichen planus.  

PubMed

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

2014-06-01

244

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.

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

2014-01-01

245

Observational and Model Constraints on Glacial Erosion  

NASA Astrophysics Data System (ADS)

Quantifying the controls on glacial erosion over geologic timescales is necessary to understand the role of Cenozoic climate change on the development of modern mountain belts. Unfortunately, understanding the spatial distribution of glacial erosion during repeated glaciations has proven difficult. We present results that integrate bedrock and detrital thermochronometer cooling ages with a glacial landscape evolution model. We use this to quantify the spatial distribution and temporal variability of glacial erosion in the Coast Mountains, British Columbia, Canada. A total of 100 apatite (U-Th)/He and 106 fission track single grain ages are presented from modern outwash of the Tiedemann Glacier whose catchment elevations range from 530-3960 m a.s.l.. Detrital thermochronometer ages utilize the tendency of thermochronometer cooling ages to increase with elevation and provide a sediment tracer for the elevation that eroded sediment is derived from. Bedrock ages used include 79 apatite (U-Th)/He ages collected in multiple catchments. Erosion rates derived from bedrock ages are compared to predicted erosion rates from a shallow-ice approximation glacial landscape evolution model of the region. Results from the observed distribution of detrital ages indicate that maximum glacial erosion occurs between elevations of 1200-1800m. Furthermore, near-uniform erosion is documented beneath the glacier with nearly all sediment derived from between elevations of 650- 3000 m a.s.l. Second, comparison of erosion rates derived from bedrock thermochronometer ages with the landscape evolution model suggest that a linear glacial sliding velocity is the primary control on erosion (r2=0.6). This result is important as it provides observational validation of the linear slide velocity erosion rule for million-year timescales. Finally, comparison of model and thermochronometer derived erosion rates reveals that active subglacial erosion occurs for only ~10-20% of a glacial-interglacial cycle. Taken together, these results highlight significant temporal variability in glacial erosion over a glacial-interglacial cycles as well as a new technique to quantify the spatial distribution of glacial erosion from sediments.

Ehlers, T. A.; Enkelmann, E.; Yanites, B. J.

2012-12-01

246

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

247

Hydromorphological and biological factors influencing sediment and phosphorus loss via bank erosion in small lowland rural streams in Denmark  

Microsoft Academic Search

Bank erosion was measured at 91 stream banks located in 15 Danish rural 1st and 2nd order streams over a 2-year period. Our aims were firstly to examine factors controlling spatial variation in bank erosion, secondly to estimate sediment and phosphorus (P) loss via bank erosion. The overall mean bank erosion rate was 11 mm year-1. Bank erosion rate over

A. Laubel; B. Kronvang; A. B. Hald; C. Jensen

2003-01-01

248

Branchbox Breakwater Design at Pickleweed Trail, Martinez, CA, Section 227 Demonstration Project.  

National Technical Information Service (NTIS)

The objective of this Coastal and Hydraulics Engineering Technical Note (CHETN) is to provide a preliminary design of the branchbox breakwater for the Martinez project site in the National Shoreline Erosion Control Development and Demonstration Program (S...

S. T. Maynord M. F. Winkler D. E. Demko

2006-01-01

249

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

250

Erosion of dust aggregates  

NASA Astrophysics Data System (ADS)

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 ms-1 and above. Though fractal aggregates as formed during the first growth phase are most susceptible to erosion, we observe erosion of aggregates with rather compact surfaces as well. Conclusions: We find that bombarding a larger target aggregate with small projectiles results in erosion for impact velocities as low as a few ms-1. More compact aggregates suffer less from erosion. With increasing projectile size the transition from accretion to erosion is shifted to higher velocities. This allows larger bodies to grow through high velocity collisions with smaller aggregates.

Seizinger, A.; Krijt, S.; Kley, W.

2013-12-01

251

Soil erosion rates from mixed soil and gravel surfaces in a wind tunnel  

SciTech Connect

Protective barriers have been identified as integral components of plans to isolate defense waste on the Hanford Site. The use of natural materials to construct protective barriers over waste site is being considered. Design requirements for protective barriers include preventing exposure of buried waste, and restricting penetration or percolation of surface waters through the waste zone. Studies were initiated to evaluate the effects of wind erosion on candidate protective barrier surfaces. A wind tunnel was used to provide controlled erosive stresses and to investigate the erosive effects of wind forces on proposed surface layers for protective barriers. Mixed soil and gravel surfaces were prepared and tested for resistance to wind erosion at the Pacific Northwest Laboratory Aerosol Wind Tunnel Research Facility. These tests were performed to investigate surface deflation caused by suspension of soil from various surface layer configurations and to provide a comparison of the relative resistance of the different surfaces to wind erosion. Planning, testing, and analyzing phases of this wind erosion project were coordinated with other tasks supporting the development of protective barriers. These tasks include climate-change predictions, field studies and modeling efforts. This report provides results of measurements of deflation caused by wind forces over level surfaces. Section 2.0 reviews surface layer characteristics and previous relevant studies on wind erosion, describes effects of erosion, and discusses wind tunnel modeling. Materials and methods of the wind tunnel tests are discussed in Section 3.0. Results and discussion are presented in Section 4.0, and conclusions and recommendations Section 5.0. 53 refs., 29 figs., 7 tabs.

Ligotke, M.W.; Klopfer, D.C.

1990-08-01

252

Why does project planning fail; A look at the basics of planning in an era of sophisticated project control tools  

SciTech Connect

The technology of project controls have become increasingly sophisticated. Some say that the technological advancements of the Nineteen-Eighties represented a maturation of project control tools. Others say that the advancements were merely bells and whistles that added little or nothing to the project management process. Above it all, as we enter the Nineties, there is a popular outcry to get back to the basics of planning. The genesis of this outcry is the sobering impact of significant cost overruns and schedule extensions, even on projects that have employed the most advanced project control tools and systems. This paper examines the merits of taking a strategic approach to the project planning process. Within that context, there are basic goals of planning which are enduring through the life cycle of the project. Key reasons for failure and inability to achieve the goals of project planning are explained. By examining the goals of project planning and the reasons for failure, insight is provided into the role of project controls specialists and sophisticated project control tools in meeting the challenges of complex project management in the 1990's.

Foley, M. (Liberty Consulting Group, Atlanta, GA (US)); Luciano, G. (Cleveland Electric Illuminating Co., OH (United States))

1991-01-01

253

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

254

Optimum Production Control and Workforce Scheduling of Machining Project  

NASA Astrophysics Data System (ADS)

Through the proposed model in this study, the production control with the consideration of workforce scheduling for advanced manufacturing systems becomes realistically and concretely solvable. This study not only meditates the concept of balancing machine productivity and human ability into the objective, but also implements Calculus of Variations to optimize the profit for a deterministic production quantity. In addition, the optimum solutions of dynamic productivity control and workforce scheduling are comprehensively provided. Moreover, the decision criteria for selecting the optimum solution and the sensitivity analysis of the critical variables are fully discussed. This study definitely contributes the applicable strategy to control the productivity and workforce in manufacturing and provides the valuable tool to conclusively optimize the profit of a machining project for operations research in today`s manufacturing industry with profound insight.

Lan, Tian-Syung; Lo, Chih-Yao; Hou, Cheng-I.

255

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

256

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.

257

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

258

Evaluation of Erosion Hazards.  

National Technical Information Service (NTIS)

Mandated by Section 577 of the National Flood Insurance Reform Act of 1994 (Public Law 103-325), this independent report, Evaluation of Erosion Hazards, provides a much-needed and valuable assessment of coastal erosion and the resulting loss of property a...

2000-01-01

259

Numerical simulation of the erosion in the 90° elbow  

NASA Astrophysics Data System (ADS)

In the process of natural gas transportation, cement production and coal-fired power, the gas-solid two-phase flow exists widely in pipelines. The existence of solid particles may cause the erosion of the pipeline, especially in the elbow of the pipeline. Equations used to predict erosion rate are usually obtained from well-controlled experimental tests for solid particles carried in a gas or liquid flow. The particle impact speed and impact angle affect the erosion process and are two major parameters in most erosion equations. In this paper, the erosion of 90° elbow was studied by using Computational Fluid Dynamics (CFD), Discrete Particle Model (DPM) and erosion equations. The maximum erosion rate and the erosion position were reported. Particle size does not influence the erosion rate when particle size is bigger than a certain degree. When the mass ratio of sand loading to fluid is less than 1, erosion ratio is proportional to the loading mass. The erosion rate is lower for larger radius elbow, and the erosion rate is greatly declined by using the plugged tee instead of an elbow.

Deng, Yunzhong; Liu, Yinhe; Chen, Jianying; Zhang, Yongjian

2013-07-01

260

Technical Assistance Project for the Minnesota Pollution Control Agency  

SciTech Connect

This report was prepared in response to a request for technical assistance from the Minnesota Pollution Control Agency (MPCA). The U.S. Department of Energy's (DOE) Office of Energy Efficiency and Renewable Energy supported the National Renewable Energy Laboratory (NREL) in its response to this request through the Technical Assistance Project. Discussion with the MPCA identified the following as the highest-priority questions: What is the effect of (1) size of Renewable Energy Reserve (RER) and (2) duration of allocation award on (a) NOx emissions in Minnesota and (b) retail electricity prices? What data is available on the response of wind energy development to financial incentives? This report addresses those questions.

Vimmerstedt, L.

2006-12-01

261

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

262

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...the analysis of effects on the Management...the disclosure of cumulative effects to wildlife species...Invasive Plant Control Project Final Environmental...the analysis of effects for the same...

2013-10-30

263

Cost and time control of construction projects: inhibiting factors and mitigating measures in practice  

Microsoft Academic Search

Despite the availability of various control techniques and project control software many construction projects still do not achieve their cost and time objectives. Research in this area so far has mainly been devoted to identifying causes of cost and time overruns. There is limited research geared towards studying factors inhibiting the ability of practitioners to effectively control their projects. To

Yakubu Adisa Olawale; Ming Sun

2010-01-01

264

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

265

Fluvial Erosion Measurements of Streambank Using Photo-Electronic Erosion Pins (peep)  

NASA Astrophysics Data System (ADS)

Cohesive streambank erosion is characterized by two main mechanisms, fluvial entrainment of individual particles and bank failure due to gravity (Thorne, 1980). In this study, the relative importance of fluvial erosion (compared to mass failure) was determined in two reaches from different locations of the Clear Creek Watershed (CCW). The main goal of the project was the identification of the key erosion process at each site. Beyond the distinguished flow conditions (hydraulic forces), different stream orders, and land-use, no further attempts were made to identify other key driving agents behind the erosion, such subaerial processes (e.g., seepage, freeze/thaw) acting at the cohesive riverbanks (Lindow et al., 2009). Erosion lengths up to 38 cm were detected. The bank erosion monitoring at high resolution intervals due to the PEEPS allowed for better characterization the fluvial erosion occurring at this site and develop a correspondence between sedigraphs and hydrographs. .Similar statistical methods were used at both sites to support our findings. The moving average identified the dominant trend of the data and the variability of the erosion lengths at the two sites. Further, the use of the Shewhart Charts allowed us to detect the critical erosion events during the period of observation. Finally the overall performance of the PEEPs was evaluated during this study. A correlation analysis was conducted between the direct measurements of traditional methods (e.g., erosion pins, geodetical surveys, measure tape) and the automated data recorded by the PEEP. The maximum error between manual and automated measurements of the exposed length of the PEEPs was less than 27%. The error between the channel survey and the automated PEEP measurements was less than 14%.

Sutarto, T.; Papanicolaou, T.; Wilson, C. G.; Bertrand, F.

2010-12-01

266

Modeling Erosion under Future Climates with the WEPP Model.  

National Technical Information Service (NTIS)

The Water Erosion Prediction Project Climate Assessment Tool (WEPPCAT) was developed to be an easy-to-use, web-based erosion model that allows users to adjust climate inputs for user-specified climate scenarios. WEPPCAT allows the user to modify monthly m...

D. P. Guertin M. A. Nearing T. Bayley T. Jefferson T. Johnson W. Elliot

2010-01-01

267

Erosion dynamics of a wet granular medium.  

PubMed

Liquid may give strong cohesion properties to a granular medium, and confer a solidlike behavior. We study the erosion of a fixed circular aggregate of wet granular matter subjected to a flow of dry grains inside a half-filled rotating drum. During the rotation, the dry grains flow around the fixed obstacle. We show that its diameter decreases linearly with time for low liquid content, as wet grains are pulled out of the aggregate. This erosion phenomenon is governed by the properties of the liquids. The erosion rate decreases exponentially with the surface tension while it depends on the viscosity to the power -1. We propose a model based on the force fluctuations arising inside the flow, explaining both dependencies: The capillary force acts as a threshold and the viscosity controls the erosion time scale. We also provide experiments using different flowing grains, confirming our model. PMID:24125259

Lefebvre, Gautier; Jop, Pierre

2013-09-01

268

Erosion dynamics of a wet granular medium  

NASA Astrophysics Data System (ADS)

Liquid may give strong cohesion properties to a granular medium, and confer a solidlike behavior. We study the erosion of a fixed circular aggregate of wet granular matter subjected to a flow of dry grains inside a half-filled rotating drum. During the rotation, the dry grains flow around the fixed obstacle. We show that its diameter decreases linearly with time for low liquid content, as wet grains are pulled out of the aggregate. This erosion phenomenon is governed by the properties of the liquids. The erosion rate decreases exponentially with the surface tension while it depends on the viscosity to the power -1. We propose a model based on the force fluctuations arising inside the flow, explaining both dependencies: The capillary force acts as a threshold and the viscosity controls the erosion time scale. We also provide experiments using different flowing grains, confirming our model.

Lefebvre, Gautier; Jop, Pierre

2013-09-01

269

Serum Level of Interleukin 17 in Patients with Erosive and Non erosive Oral Lichen Planus  

PubMed Central

Background and aims Oral lichen planus is a relatively common chronic oral mucosal disease of unknown etiology. Regarding numerous studies on the immunologic factors involved in the etiology of lichen planus, the present study evaluated the serum interleukin-17 (IL-17) level in patients with erosive and non-erosive oral lichen planus. Materials and methods This descriptive analytical study included 24 patients with erosive oral lichen planus (EOLP), 24 patients with non-erosive oral lichen planus (NEOLP) and 24 healthy volunteered as control. Blood samples of the subjects underwent ELISA, using special kits, to determine serum interleukin-17 levels. Data was analyzed using with descriptive statistic, chi-square test, and one-way ANOVA and Tukey post-hoc test with SPSS 16 software. Results EOLP patients showed a high level of serum IL-17 compared with NEOLP patents and control groups (EOLP=184.16 ± 12.41 pg/mL, NEOLP=106.09±10.78 pg/mL, control=15.50 ± 4.34 pg/mL, P - 0.001). Conclusion High level of serum IL-17 in erosive oral lichen planus patients compared to the non-erosive type and healthy individuals may be the reason for higher inflammation and atrophy in the erosive type.

Pouralibaba, Firoz; Babaloo, Zohre; Pakdel, Farzaneh; Aghazadeh, Marziye

2013-01-01

270

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.

271

Investigation 4 - Erosion  

NSDL National Science Digital Library

This webpage from the Utah Education Network provides directions for a tabletop simulation of erosion by wind and water, requiring only everyday materials. The page includes background information, as well as extension activities.

2010-06-28

272

Variables in turbine erosion  

NASA Technical Reports Server (NTRS)

Study of impact erosion in the operation of turbomachinery is undertaken to predict the results for particular designs. The test program investigates the effects of turbine stator blade shape, rotor blade shape, and variations in test conditions.

Baughman, J. R.; Spies, R.

1970-01-01

273

Integrated Project Scheduling and Staff Assignment with Controllable Processing Times  

PubMed Central

This paper addresses a decision problem related to simultaneously scheduling the tasks in a project and assigning the staff to these tasks, taking into account that a task can be performed only by employees with certain skills, and that the length of each task depends on the number of employees assigned. This type of problems usually appears in service companies, where both tasks scheduling and staff assignment are closely related. An integer programming model for the problem is proposed, together with some extensions to cope with different situations. Additionally, the advantages of the controllable processing times approach are compared with the fixed processing times. Due to the complexity of the integrated model, a simple GRASP algorithm is implemented in order to obtain good, approximate solutions in short computation times.

Framinan, Jose M.

2014-01-01

274

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

275

Wear: Corrosion and erosion  

NASA Technical Reports Server (NTRS)

The various forms of corrosion are discussed and the role of localized electrochemical reactions in the wear of sliding surfaces are considered. It is stated that there is evidence that fretting corrosion, stress corrosion cracking, corrosion fatigue, and erosion corrosion have as a common basis the localized electrochemical reactions caused by a combination of the induced homogeneity of the surfaces and the corrosive environment. Several processes leading to erosive wear are discussed.

Rowe, C. N.

1973-01-01

276

Erosion Prevention in Boilers  

Microsoft Academic Search

\\u000a Erosion is a process of wear in which materials are removed from a solid surface by the action of solid particles impinging\\u000a on it. This type of wear is common in many industrial devices, including boilers. The combustion products of coal contain\\u000a fly ash particles, which impinge on boiler tubes or fan blades and erode them. Fly ash erosion is

Prabir Basu; Cen Kefa; Louis Jestin

277

IT project management control and the Control Objectives for IT and related Technology (CobiT) framework  

Microsoft Academic Search

Motivated by scarce academic consideration of project management control frameworks, this article explores usage, value and structure of frameworks with a focus on the popular Control Objectives for IT and related Technology (CobiT) construct. We attempt to add to an empirically validated structure of internal control over IT project management by including CobiT's views on the intended domain of content.

Edward W. N. Bernroider; Milen Ivanov

2011-01-01

278

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.

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

2013-01-01

279

Spinal projection neurons control turning behaviors in zebrafish.  

PubMed

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

2013-08-19

280

An alternate approach to hospital cost control: the Rochester project.  

PubMed Central

The rapid escalation in health care costs has demonstrated a need to control costs in general and hospital costs in particular. In New York State, efforts at control have followed one of several paths, including reduction of Medicaid program expenditures, elimination of hospital beds, and prospective reimbursement of hospital costs. Although some success has been achieved in each of these areas, hospital costs containment has not been as successful as had been hoped. A new project called MAXICAP, being developed in the Rochester region, seeks to link payment with regional hospital planning. MAXICAP represents a voluntary attempt by hospitals, third party payers, planners, consumers, and governmental agencies to devise a prospective hospital payment system. Under this system community hospital plans in the Rochester region would be integrated and a cap imposed on both revenues and expenses for acute hospital care. The principal advantage of the MAXICAP is that it offers a mechanism for linking hospital planning with payment functions on a regional basis. The principal disadvantage is that the success of the MAXICAP depends upon the voluntary cooperation of the vast majority of the acute care hospitals in the area--hospitals that may be scattered throughout a relatively large region.

Sorensen, A A; Saward, E W

1978-01-01

281

Suboptimal projective control of a pressurized water reactor  

SciTech Connect

The time- and oxide field-dependencies of interface trap (N{sub it}) formation in MOSFETs have been studied following pulsed ionizing radiation. Results are compared with the two-stage model for Nit formation involving slow drift of radiation-induced H{sup +} ions in the SiO{sub 2}. Detailed data on the gate oxide field dependence during each individual stage are presented and discussed. A model is developed for the production of H{sup +} throughout the oxide. Calculations based on this model correctly predict the complete time dependent N{sub it} formation is at a maximum near zero first stage gate bias. This unexpected behavior apparently arises from the oxide field dependence of the H{sup +} production during the first stage. A suboptimal output feedback approach for control of the pressurized water reactor (PWR) in the H. B. Robinson nuclear power plant is presented. Optimal state feedback linear quadratic regulator (LQR) theory with pole placement capability is extended to obtain a suboptimal projective controller for such cases where the entire state vector is inaccessible for measurement and feedback purposes. The appealing feature of the proposed approach is that it is possible to select the weighting matrices in the quadratic cost functional such that the resulting control law would nearly minimize the cost, and at the same time can assign a subspectrum of the closed-loop system to preassigned desired locations. Additionally, the design algorithm is computationally attractive, since regardless of the dimension of the PWR model the approach mainly involves low-order matrix computations.

Saif, M. (Simon Fraser Univ., Burnaby, BC V5A 156 (CA))

1989-12-01

282

Erosion and the rocks of Venus  

NASA Technical Reports Server (NTRS)

Photographs of the surface of Venus returned by the Venera 9 and 10 spacecraft have revealed the presence of smooth and angular rockline forms. Two mechanisms previously suggested (Sagan, 1975) for erosion of crater ramparts on the surface of Venus might also explain the erosion of rocks. Chemical weathering by the hydrochloric, hydrofluoric, and sulfuric acids present in the atmosphere of Venus may have been sufficient to erode angular projections of silicous rocks. Alternatively, the contours of rocks containing such low-melting materials as NaOH, KOH, HgS and KNO2 may have softened as the result of exposure to the high surface temperatures of the planet.

Sagan, C.

1976-01-01

283

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

284

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.

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

2011-01-01

285

77 FR 29351 - Disease, Disability, and Injury Prevention and Control; Special Interest Projects (SIPs): Initial...  

Federal Register 2010, 2011, 2012, 2013

...Disability, and Injury Prevention and Control; Special Interest Projects...Increase Support for Evidence-based Tobacco Control, SIP12-060, Panel A, initial...Increase Support for Evidence-based Tobacco Control, SIP12-060, Panel A,...

2012-05-17

286

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 Cohrs

2014-01-01

287

Projects in Industrial Pollution Control Program, July 1972.  

National Technical Information Service (NTIS)

A compilation is presented of the information sheets of the 246 projects initiated since fiscal year 1967 through fiscal year 1972. Each sheet contains the objectives, statistical information, and a brief description of an initiated project. General intro...

G. Rey G. Keeler

1972-01-01

288

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

289

EPRI condenser-related research projects  

SciTech Connect

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 and scaling, engineering design, nondestructive evaluation techniques, and special issues of closed-cycle cooling systems.

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

1981-05-01

290

Urban Drainage and Flood Control Projects Economic, Legal and Financial Aspects.  

National Technical Information Service (NTIS)

Techniques for evaluating minor and major Urban Drainage and Flood Control (UDFC) Projects are described. Economic, political, engineering, financial and legal problems must be faced prior to implementation of proper levels of these projects. The measurem...

N. S. Grigg L. H. Botham L. Rice W. J. Shoemaker L. S. Tucker

1976-01-01

291

Effect of polyacrylamide as a post-fire erosion mitigation treatment during consecutive rainstorms  

NASA Astrophysics Data System (ADS)

Anionic polyacrylamide (PAM) has been proven to be an effective chemical soil amendment for reducing erosion in arable lands and infrastructure projects, but few attempts have been made to use it as a post-fire mitigation measure. Moreover, the mechanisms by which PAM reduces soil erosion are not fully understood. In this study, we tested the use of 50 kg/ha granular PAM as a post-fire amendment on infiltration rate (IR), runoff and soil loss both in laboratory and field experiments involving multiple rainstorms. In the laboratory experiments, three consecutive storms separated by drying periods were applied by means of a rainfall simulator to two contrasting soils affected by fire (Humic Cambisol and Calcic Regosol). During the 1st rainstorm, PAM decreased IR and increased runoff in both soils due to an increase in viscosity of the runoff and soil solution. At the same time, a reduction in soil loss was observed in both PAM-treated soils compared to the untreated controls. During the first drying period, PAM was irreversibly adsorbed to soil particles, and in the following storms PAM-induced soil loss reduction persisted while the effect of the polymer on IR and runoff was reversed. Differences in the effect of PAM on soil erosion between soils were attributed to changes in the electrolyte concentration of runoff and soil solution. The positive effect of PAM on post-fire soil loss was confirmed in field experiments with erosion plots constructed in the burnt Calcic Regosol. The application of 25 and 50 kg/ha of granular PAM reduced soil erosion by 23 and 57%, respectively, compared to the untreated control. Runoff was reduced only in the 50 kg/ha treatment. It is suggested that the application of PAM could be a good alternative to current post-fire erosion mitigation measures.

Inbar, Assaf; Ben-Hur, Meni; Sternberg, Marcelo; Liñares, Marcos

2014-05-01

292

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

293

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

294

Erosion of composite ceramics  

SciTech Connect

The theoretical basis to describe solid-particle erosion of monolithic ceramics is well developed. In many cases, the models can account for the impact velocity, impact angle and erodent-size dependencies of the steady-state erosion rate. In addition, the models account for effects of materials parameters such as fracture toughness and hardness. Steady-state erosion measurements on a wide variety of composite ceramics, including SiC whisker-reinforced Al[sub 2]O[sub 3], Si[sub 3]N[sub 4] containing Si[sub 3]N[sub 4] or SiC whiskers, Y[sub 2]O[sub 3]-stabilized ZrO[sub 2] reinforced with SiC whiskers, and duplex-microstructure Si[sub 3]N[sub 4] have been reported. The theories developed for monolithic ceramics are, however, less successful in describing the results for composites.

Routbort, J.L.

1992-08-01

295

Erosion of composite ceramics  

SciTech Connect

The theoretical basis to describe solid-particle erosion of monolithic ceramics is well developed. In many cases, the models can account for the impact velocity, impact angle and erodent-size dependencies of the steady-state erosion rate. In addition, the models account for effects of materials parameters such as fracture toughness and hardness. Steady-state erosion measurements on a wide variety of composite ceramics, including SiC whisker-reinforced Al{sub 2}O{sub 3}, Si{sub 3}N{sub 4} containing Si{sub 3}N{sub 4} or SiC whiskers, Y{sub 2}O{sub 3}-stabilized ZrO{sub 2} reinforced with SiC whiskers, and duplex-microstructure Si{sub 3}N{sub 4} have been reported. The theories developed for monolithic ceramics are, however, less successful in describing the results for composites.

Routbort, J.L.

1992-08-01

296

Arctic Coastal Erosion Modeling  

NASA Astrophysics Data System (ADS)

A process-based coastal erosion/shoreline change model has been developed for Arctic coastal bluffs subject to niche erosion/block collapse. The model explicitly accounts for many environmental/geographic variables including: water temperature, water level, wave height, and bluff height. The model was originally developed for a small coastal segment near Drew Point, Beaufort Sea, Alaska. This coastal setting has experienced a dramatic increase in erosion since the early 2000's. The bluffs at this site are 3-4 m tall and consist of ice-wedge bounded blocks of fine-grained sediments cemented by ice-rich permafrost and capped with a thin organic layer. The bluffs are typically fronted by a narrow (~ 5 m wide) beach or none at all. During a storm surge, the sea contacts the base of the bluff and a niche is formed through thermal and mechanical erosion. The niche grows both vertically and laterally and eventually undermines the bluff, leading to block failure or collapse. The fallen block is then eroded both thermally and mechanically by waves and currents, which must occur before a new niche forming episode may begin. The model has been calibrated based on shoreline change data at Drew Point for two time periods: 1979-2002 and 2002-2007. Measured and modeled shoreline change rates were about 8 m/yr and 16 m/yr, for the earlier and later periods, respectively. In this paper, this work is extended to include modeling and measurement of coastal erosion at Drew Point on an annual basis for the period 2007-2010. In addition, the model is applied at three other Arctic coastal locations - Elson Lagoon, Cape Halkett, and Barter Island - where niche erosion/block collapse prevails.

Ravens, T. M.; Jones, B.; Zhang, J.; Tweedie, C. E.; Erikson, L. H.; Gibbs, A.; Richmond, B. M.

2011-12-01

297

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

Microsoft Academic Search

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

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

2010-01-01

298

Calibrating thermal erosion models along an Arctic coastline  

NASA Astrophysics Data System (ADS)

Coastal erosion rates of 20-30 meters per year have been documented along Alaska’s Beaufort Sea coastline, and a number of studies suggest that erosion rates have accelerated as a result of climate change. However, a lack of direct observational evidence has limited our progress in quantifying the role of climate change on coastal erosion rates in the Arctic. In particular, while longer ice-free periods are likely to lead to both warmer surface waters and longer fetch, the relative roles of thermal and mechanical (wave) erosion in driving coastal retreat have not been comprehensively quantified. We focus on the potential magnitude of thermal erosion along a permafrost coastline in the northern National Petroleum Reserve-Alaska (NPR-A), where erosion rates have averaged 10-15 meters/year over two years of direct monitoring. We take advantage of these extraordinary rates of coastal erosion to directly observe erosion processes via time-lapse photography, while monitoring temperature, solar radiation and wind speed at the same time. These combined observations are used to calibrate models of thermal erosion. Our observations suggest that virtually all of the erosion in this setting can be explained as a purely thermal process. Coastal bluffs are first notched and then topple into the ocean, failing dominantly along ice wedges that serve as planes of weakness. Furthermore, the high ice content and the fine grain size of the coastal plain materials that comprise the bluffs appear to limit any strong negative feedback on erosion rates, since the sediments are readily dispersed on the shallow shelf. Although erosion driven purely by thermal processes may be unique to this particular coastal zone, these observations implicate a direct relationship between climatic warming and landscape change. Erosion of sandy coastlines in other parts of the NPR-A may also be ultimately controlled by thermal energy, once a thin veneer of clastic material is removed by wave action from late summer storms.

Wobus, C. W.; Anderson, R. S.; Overeem, I.; Urban, F. E.; Clow, G. D.; Stanton, T. P.

2009-12-01

299

Erosion of composite materials  

NASA Technical Reports Server (NTRS)

A model for describing the response of uncoated and coated fiber reinforced composites subjected to repeated impingements of liquid (rain) droplets is presented. The model is based on the concept that fatigue is the dominant factor in the erosion process. Algebraic expressions are provided which give the incubation period, the rate of mass loss past the incubation period, and the total mass loss of the material during rain impact. The influence of material properties on erosion damage and the protection offered by different coatings are discussed and the use of the model in the design in the design of structures and components is illustrated.

Springer, G. S.

1980-01-01

300

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.

301

Research on effective cost control in highway projects  

Microsoft Academic Search

Highway construction cycle is quite long and technology involved is complicated. Highway project, as a whole, is comprehensive by taking in all kinds of factors in consideration, involving both the technical aspects and the social aspects. It also consumes a lot of manpower and material resources. Currently, funds for highway construction are not abundant and stable, and for some projects,

Jieyu Wang; Haicheng Xu

2011-01-01

302

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

303

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

304

Guidance and Control Software Project Data - Volume 4: Configuration Management and Quality Assurance Documents  

NASA Technical Reports Server (NTRS)

The Guidance and Control Software (GCS) project was the last in a series of software reliability studies conducted at Langley Research Center between 1977 and 1994. The technical results of the GCS project were recorded after the experiment was completed. Some of the support documentation produced as part of the experiment, however, is serving an unexpected role far beyond its original project context. Some of the software used as part of the GCS project was developed to conform to the RTCA/DO-178B software standard, "Software Considerations in Airborne Systems and Equipment Certification," used in the civil aviation industry. That standard requires extensive documentation throughout the software development life cycle, including plans, software requirements, design and source code, verification cases and results, and configuration management and quality control data. The project documentation that includes this information is open for public scrutiny without the legal or safety implications associated with comparable data from an avionics manufacturer. This public availability has afforded an opportunity to use the GCS project documents for DO-178B training. This report provides a brief overview of the GCS project, describes the 4-volume set of documents and the role they are playing in training, and includes configuration management and quality assurance documents from the GCS project. Volume 4 contains six appendices: A. Software Accomplishment Summary for the Guidance and Control Software Project; B. Software Configuration Index for the Guidance and Control Software Project; C. Configuration Management Records for the Guidance and Control Software Project; D. Software Quality Assurance Records for the Guidance and Control Software Project; E. Problem Report for the Pluto Implementation of the Guidance and Control Software Project; and F. Support Documentation Change Reports for the Guidance and Control Software Project.

Hayhurst, Kelly J. (Editor)

2008-01-01

305

Interdigital erosions - tinea pedis?  

PubMed

Interdigital erosions are frequently due to tinea pedis. However, other infectious conditions, such as candidiasis, erythrasma or bacterial infections, can generate lesions that cannot be differentiated at the clinical level. Microbiological tests are therefore necessary. This clinical case shows a man with interdigital lesions of 10 months of evolution that are not responding to antifungal treatment. PMID:23210102

Orgaz-Molina, Jacinto; Orgaz-Molina, Maria Carmen; Cutugno, Marilena; Arias-Santiago, Salvador

2012-10-01

306

Glacier Goo Erosion Experiments  

NSDL National Science Digital Library

Using a glacier proxy, students design an experiment to connect glacial erosion with glacial flow. Students choose from a variety of materials, determined what question they want their experiment or experiments to answer, design the procedure, test the experiment, and write up a lab report on the experiment.

Headley, Rachel

307

Erosion of polyurethane insulation.  

NASA Technical Reports Server (NTRS)

Detailed description of the test program in which erosion of the spray foam insulation used in the S-II stage of the Saturn-V Apollo launch vehicle was investigated. The behavior of the spray foam was investigated at the elevated temperature and static pressure appropriate to the S-II stage environment, but in the absence of the aerodynamic shear stress.

Kraus, S.

1973-01-01

308

The effects of land use on runoff and soil nutrient losses in a gully catchment of the hilly areas: implications for erosion control  

Microsoft Academic Search

Serious soil erosion is one of the major issues threatening sustainable land use in semiarid areas, especially in the Loess\\u000a Plateau of China. Understanding the effects of land use on soil and water loss is important for sustainable land use strategy.\\u000a Two sub-catchments: catchment A (CA) and catchment B (CB) with distinct land uses were selected to measure soil moisture,

Wang Jun; Fu Bojie; Qiu Yang; Chen Liding; Chen Chen; Hu Baodong

2005-01-01

309

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

310

Investment Risk Assessment and Control in Tourism Project Based on Portfolio Theory  

Microsoft Academic Search

By applying mean variance model and CAPM model of modern portfolio theory, the paper constructs portfolio risk decision making model in tourism project. Then, we assess investment risk in tourism project by combining the model with present situation of tourism investment in China. The analysis provides proof for enterprises when making risk controlling strategies in tourism project investment.

Xu Xu-song; Chen Mei

2009-01-01

311

DEVELOPING AN INTELLIGENT WORKFLOW MANAGEMENT SYSTEM TO MANAGE PROJECT PROCESSES WITH DYNAMIC RESOURCE CONTROL  

Microsoft Academic Search

This research develops an intelligent workflow management system (IWMS) to efficiently and effectively manage complex processes of projects, control project flows, and allocate available resources for project execution dynamically across organizational boundaries. Process logics are embedded in predicate (IF-THEN) rules that can be activated when condition is met to drive workflows. In this paper, an expert system inference engine is

Amy J. C. Trappey; Tzu-An Chiang; Sam Ke

2006-01-01

312

Control in outsourced ISD projects based on psychological contract: a multiple case study  

Microsoft Academic Search

Purpose – The paper seeks to investigate the effects of psychological contract on control mechanisms in outsourced ISD projects, based on control theories and psychological contract theories. Design\\/methodology\\/approach – The paper is a multiple case study involving five outsourced projects completed by one of the largest and most successful telecommunication vendors in China. The company was the client in three

Xiaoyan Li; Jiye Mao; Jing Qian

2010-01-01

313

Three Mine Fire Control Projects in Northeastern Pennsylvania.  

National Technical Information Service (NTIS)

Work and costs involved in controlling three large fires in abandoned mines in the anthracite region of Pennsylvania are presented in detail. Three basic control techniques were successfully employed by the Bureau of Mines: forming underground fire-contai...

A. H. Harvey B. J. Moore H. A. Dierks R. H. Whaite

1971-01-01

314

Soil erosion and agricultural sustainability  

PubMed Central

Data drawn from a global compilation of studies quantitatively confirm the long-articulated contention that erosion rates from conventionally plowed agricultural fields average 1–2 orders of magnitude greater than rates of soil production, erosion under native vegetation, and long-term geological erosion. The general equivalence of the latter indicates that, considered globally, hillslope soil production and erosion evolve to balance geologic and climate forcing, whereas conventional plow-based agriculture increases erosion rates enough to prove unsustainable. In contrast to how net soil erosion rates in conventionally plowed fields (?1 mm/yr) can erode through a typical hillslope soil profile over time scales comparable to the longevity of major civilizations, no-till agriculture produces erosion rates much closer to soil production rates and therefore could provide a foundation for sustainable agriculture.

Montgomery, David R.

2007-01-01

315

Repair of erosion in RA--shifting the balance to formation  

PubMed Central

Repair of bone erosions in rheumatoid arthritis has been considered a difficult goal to achieve. However—with better therapies at hand to control synovial inflammation—sensitive ?CT imaging techniques now available confirm that repair of bone erosion is possible, and begins at the base of erosive lesions.

Gravallese, Ellen M.; Walsh, Nicole C.

2014-01-01

316

Erosion assessment in the Brazilian Cerrados using multi-temporal SAR imagery  

Microsoft Academic Search

Regional assessment of soil erosion is an important step in the conservation of natural resources. A general problem is the availability of accurate regional data, especially in tropical regions. SAR imagery can play a role through direct detection of erosion features and the assessment of factors controlling erosion. This study presents preliminary results on the application of multitemporal ENVISAT ASAR

Anton Vrieling; Silvio C. Rodrigues

2005-01-01

317

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

318

Soil Erosion: Advanced Crop and Soil Science. A Course of Study.  

ERIC Educational Resources Information Center

The course of study represents the last of six modules in advanced crop and soil science and introduces the agriculture student to the topic of soil erosion. Upon completion of the two day lesson, the student will be able to: (1) define conservation, (2) understand how erosion takes place, and (3) list ways of controlling wind and water erosion.…

Miller, Larry E.

319

Reducing Erosion from Surface Irrigation by Furrow Spacing and Plant Position  

Microsoft Academic Search

Erosion is a serious problem in many furrow-irrigated fields. Ero- sion abatement can be costly or inconvenient. Plant placement, row spacing, and choice of trafficked or non-trafficked furrow have not been thoroughly exploited for furrow erosion control. It was hypoth- esized that reducing furrow spacing and plant distance to the furrow would reduce erosion for equal amounts of water applied.

R. E. Sojka; M. J. Brown; E. C. Kennedy-Ketcheson

1992-01-01

320

Seismicity, seismology and erosion  

NASA Astrophysics Data System (ADS)

At the interface of geomorphology and seismology, patterns of erosion can be used to constrain seismic processes, and seismological instruments to determine geomorphic activity. For example, earthquakes trigger mass wasting in proportion to peak ground velocity or acceleration, modulated by local geologic and topographic conditions. This geomorphic response determines the mass balance and net topographic effect of earthquakes. It can also be used to obtain information about the distribution of seismic slip where instrumental observations are not available. Equally, seismometers can register the signals of geomorphic processes, revealing their location, type and magnitude. The high temporal resolution of such records can help determine the exact meteorological conditions that gave rise to erosion events, and the interactions between individual surface processes during such events. We will illustrate this synergy of disciplines with examples from active mountain belts around the world, including Taiwan, Japan, Papua New Guinea and the Alps.

Hovius, Niels; Meunier, Patrick; Burtin, Arnaud; Marc, Odin

2013-04-01

321

The relationship of control and learning to project performance  

Microsoft Academic Search

Management controls can be divided into two types that can have opposite effects on organizational learning: behavioral controls, which promote efficiency but also stifle much of the learning opportunity, and outcome controls, which foster interaction among stakeholders can add to the learning environment. This article reports on a study that confirms these observations and explores the nature of their direct

Gary Klein; Peggy M. Beranek; Ben Martz; James J. Jiang

2006-01-01

322

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

323

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

324

Spent Nuclear Fuel Project document control and Records Management Program Description  

SciTech Connect

The Spent Nuclear Fuel (SNF) Project document control and records management program, as defined within this document, is based on a broad spectrum of regulatory requirements, Department of Energy (DOE) and Project Hanford and SNF Project-specific direction and guidance. The SNF Project Execution Plan, HNF-3552, requires the control of documents and management of records under the auspices of configuration control, conduct of operations, training, quality assurance, work control, records management, data management, engineering and design control, operational readiness review, and project management and turnover. Implementation of the controls, systems, and processes necessary to ensure compliance with applicable requirements is facilitated through plans, directives, and procedures within the Project Hanford Management System (PHMS) and the SNF Project internal technical and administrative procedures systems. The documents cited within this document are those which directly establish or define the SNF Project document control and records management program. There are many peripheral documents that establish requirements and provide direction pertinent to managing specific types of documents that, for the sake of brevity and clarity, are not cited within this document.

MARTIN, B.M.

2000-05-18

325

Noise prediction and control of Pudong International Airport expansion project.  

PubMed

The Environmental Impact Assessment (EIA) process of the third runway building project of Pudong International Airport is briefly introduced in the paper. The basic principle, the features, and the operation steps of newly imported FAA's Integrated Noise Model (INM) are discussed for evaluating the aircraft noise impacts. The prediction of the aircraft noise and the countermeasures for the noise mitigation are developed, which includes the reasonable runway location, the optimized land use, the selection of low noise aircrafts, the Fly Quit Program, the relocation of sensitive receptors and the noise insulation of sensitive buildings. Finally, the expansion project is justified and its feasibility is confirmed. PMID:18373206

Lei, Bin; Yang, Xin; Yang, Jianguo

2009-04-01

326

Towards Greater Learner Control: Web Supported Project-Based Learning  

ERIC Educational Resources Information Center

Project-based learning has been suggested as an appropriate pedagogy to prepare students in information systems for the realities of the business world. Web-based resources have been used to support such pedagogy with mixed results. The paper argues that the design of web-based learning support to cater to different learning styles may give…

Guthrie, Cameron

2010-01-01

327

Controlling Landfill Emissions For Environmental Protection : Mid Auchencarroch Experimental Project  

Microsoft Academic Search

This paper assesses the long term behaviour of Mid Auchencarroch experimental landfill site in Scotland, based on characteristic landfill biodegration parameters, making useful conclusions. and analyzes the effects of waste pretreatment and landfill management techniques on landfill emissions and waste biodegradation processes. The biodegradation of Mid Auchencarroch Experimental Landfill Project is studied in four different cells with different waste input

Telemachus C. Koliopoulos; D. M. Georgia Koliopoulou

328

Skills Conversion Project, Chapter 8, Pollution Control. Final Report.  

ERIC Educational Resources Information Center

The Skills Conversion Project conducted by the National Society of Professional Engineers sought to study the transition mechanisms required to transfer available technical manpower from aerospace and defense industries into other areas of employment in private industry and public service. Fourteen study teams assessed the likelihood of future…

National Society of Professional Engineers, Washington, DC.

329

Projective control design for multi-zone crystal growth furnace  

Microsoft Academic Search

This paper addresses the problem of controlling the temperature profile inside a multi-zone crystal growth furnace. A minimal discrete-time state-space model of the furnace is determined by the least squares identification of a multi-input\\/multi-output (MIMO) model. An integral control structure for the discrete-time model is derived to allow reference tracking, and a state-feedback control is designed for the system by

A. Srinivasan; C. Batur; R. Veillette; B. N. Rosenthal; W. M. B. Duval

1994-01-01

330

Accelerated subduction erosion opposite the Cocos Ridge: Implications for the initiation of ridge subduction  

NASA Astrophysics Data System (ADS)

Subduction erosion has been invoked as the dominant process controlling the tectonic evolution of the Pacific margin of Costa Rica. In an erosive subduction margin, the upper plate material is incorporated into the subduction channel due to basal erosion, resulting in long term subsidence of the upper plate. Estimation of mass removal from the upper plate based on subsidence profiles of slope sediments is crucial to assessing the thickness of the subduction channel. CRISP (Costa Rica Seismogenesis Project) is designed to understand the processes that control fault zone behavior during earthquake nucleation and rupture propagation at erosional subduction zones. IODP Expedition 334 successfully recovered slope sediments offshore the Osa Peninsula where the Cocos Ridge is subducting beneath the Caribbean plate. Preliminary results from biostratigraphic dating obtained from two slope sites indicate high sediment accumulation rates in the terrestrially-sourced slope sequence, ranging from 516-236 m/my at Site U1378 in the middle slope to 1035-160 m/my at Site U1379 in the upper slope. In particular, the accumulation rate of the slope sediments, mainly composed of clayey silt/silty clay, at Site U1379 is 1035 m/my, much higher than that of slope sediments offshore Nicoya (38-99 m/my) (Kimura et al., 1997). The remarkably high accumulation rate offshore Osa could be derived from subaerial uplift triggered by the subduction of the Cocos Ridge. Concomitant with uplift, the subduction of such a bathymetric high likely accelerates the basal erosion of the upper plate. The subsidence/uplift profiles of the slope sediments offshore Osa are controlled by the high sediment accumulation rate and the basal erosion; the subsidence of the upper plate likely occurred when the rate of subduction erosion was exceeded the sediment accumulation rate on the slope. Detailed studies of sedimentary facies and benthic foraminifera faunal in slope sediments at Sites U1378 and U1379 are keys to estimate the mass removal associated with basal erosion and the thickness of the subduction channel that may elucidate earthquake processes. Kimura, G., Silver, E., et al., 1997, Proceedings of the Ocean Drilling Program Initial reports, Volume 170: College Station, Texas, Ocean Drilling Program, 458 p.

Sak, P. B.; Vannucchi, P.; Ohkushi, K.; Ujiie, K.; IODP 334 Scientific Party

2011-12-01

331

Sr-Nd-Os evidence for a stable erosion regime in the Himalaya during the past 12 Myr  

NASA Astrophysics Data System (ADS)

Modern erosion of the Himalaya, the world's largest mountain range, transfers huge dissolved and particulate loads to the ocean. It plays an important role in the long-term global carbon cycle, mostly through enhanced organic carbon burial in the Bengal Fan. To understand the role of past Himalayan erosion, the influence of changing climate and tectonic on erosion must be determined. Here we use a 12 Myr sedimentary record from the distal Bengal Fan (Deep Sea Drilling Project Site 218) to reconstruct the Mio-Pliocene history of Himalayan erosion. We use carbon stable isotopes ( ?13C) of bulk organic matter as paleo-environmental proxy and stratigraphic tool. Multi-isotopic — Sr, Nd and Os — data are used as proxies for the source of the sediments deposited in the Bengal Fan over time. ?13C values of bulk organic matter shift dramatically towards less depleted values, revealing the widespread Late Miocene (ca. 7.4 Ma) expansion of C4 plants in the basin. Sr, Nd and Os isotopic compositions indicate a rather stable erosion pattern in the Himalaya range during the past 12 Myr. This supports the existence of a strong connection between the southern Tibetan plateau and the Bengal Fan. The tectonic evolution of the Himalaya range and Southern Tibet seems to have been unable to produce large re-organisation of the drainage system. Moreover, our data do not suggest a rapid change of the altitude of the southern Tibetan plateau during the past 12 Myr. Variations in Sr and Nd isotopic compositions around the late Miocene expansion of C4 plants are suggestive of a relative increase in the erosion of High Himalaya Crystalline rock (i.e. a simultaneous reduction of both Transhimalayan batholiths and Lesser Himalaya relative contributions). This could be related to an increase in aridity as suggested by the ecological and sedimentological changes at that time. A reversed trend in Sr and Nd isotopic compositions is observed at the Plio-Pleistocene transition that is likely related to higher precipitation and the development of glaciers in the Himalaya. These almost synchronous moderate changes in erosion pattern and climate changes during the late Miocene and at the Plio-Pleistocene transition support the notion of a dominant control of climate on Himalayan erosion during this time period. However, stable erosion regime during the Pleistocene is suggestive of a limited influence of the glacier development on Himalayan erosion.

Galy, Valier; France-Lanord, Christian; Peucker-Ehrenbrink, Bernhard; Huyghe, Pascale

2010-02-01

332

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

333

Vetiver Grass: A Thin Green Line against Erosion.  

National Technical Information Service (NTIS)

Vetiver, a deeply rooting, persistent tropical grass, has for decades controlled erosion at sites in Fiji, India, and the Caribbean. The report, based on a literature review, personal contacts, site visits, and correspondence with experts in agronomy, for...

1993-01-01

334

[The Southern Cone Sub-Regional Project on Cystic Echinococcosis Control and Surveillance].  

PubMed

Southern Cone Sub-Regional Project on Cystic Echinococcosis Control and Surveillance: Argentina, Brasil, Chile and Uruguay, is a joint and collaborative tool with the aim of promoting the implementation or the strengthening of programs for disease control. The paper describes the background, the institutional aspects that regulates the structure and functions, as well as the guidelines defined in the technical and operational project. The article emphasize the achievements through Projects of Technical Cooperation among Countries, and the development of integrated and innovative approaches for prevention and control of the disease and training of human resources of the control programs. Some of the challenges are: to achieve the sustainability of the project, implementation of technical groups for analysis and assessment at request of the countries, improvement of the regional information systems, to continue training human resources of the control programs and to expand and strengthen the technical cooperation among countries. PMID:21308202

Irabedra, Pilar; Salvatella, Roberto

2010-01-01

335

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

336

Estimation of regional differences in wind erosion sensitivity in Hungary  

NASA Astrophysics Data System (ADS)

In Hungary, wind erosion is one of the most serious natural hazards. Spatial and temporal variation in the factors that determine the location and intensity of wind erosion damage are not well known, nor are the regional and local sensitivities to erosion. Because of methodological challenges, no multi-factor, regional wind erosion sensitivity map is available for Hungary. The aim of this study was to develop a method to estimate the regional differences in wind erosion sensitivity and exposure in Hungary. Wind erosion sensitivity was modelled using the key factors of soil sensitivity, vegetation cover and wind erodibility as proxies. These factors were first estimated separately by factor sensitivity maps and later combined by fuzzy logic into a regional-scale wind erosion sensitivity map. Large areas were evaluated by using publicly available datasets of remotely sensed vegetation information, soil maps and meteorological data on wind speed. The resulting estimates were verified by field studies and examining the economic losses from wind erosion as compensated by the state insurance company. The spatial resolution of the resulting sensitivity map is suitable for regional applications, as identifying sensitive areas is the foundation for diverse land development control measures and implementing management activities.

Mezõsi, G.; Blanka, V.; Bata, T.; Kovács, F.; Meyer, B.

2013-09-01

337

Polarization aberration control for ArF projection lenses  

NASA Astrophysics Data System (ADS)

High NA imaging or/and polarization illumination imaging for exposure tool requires not only scalar aberration performance but also vectorial aberration (so called polarization aberration) control. There are several methods to explain vectorial aberrations such as, Jones Matrix Pupil, Pauli spin matrix, etc. Pauli spin matrix may be intuitively easier to understand and suitable to show scalar wavefront. However, direct use of Pauli spin matrix method may not express physical meaning of vectorial aberration exactly, especially when the amount of polarization aberration is large. In this paper we would like to propose a new explanation method, which is natural expansion of scalar aberration explanation to vectorial aberration explanation and physically mostly exact form. Furthermore useful approximation of the form makes it possible to make vectorial aberration sum-operant from productoperant. Using this method, it is possible to use scalar aberration control technique, such as wavefront control, Zernike sensitivity analysis, Zernike linear combination method, etc. to vectorial aberration control.

Matsuyama, Tomoyuki; Kita, Naonori

2009-03-01

338

Erosion and Sedimentation  

NASA Astrophysics Data System (ADS)

In this book, Professor Julien provides a thorough analysis of erosion, transport and sedimentation of soil and solid particles by surface waters. The author stresses physical understanding based on Newtonian mechanics, and explains fundamental concepts pertaining to the hydrodynamic forces exerted on solid particles, with a lucid treatment of potential flow, viscous flow, turbulent flow, and boundary layers. The text features a variety of exercises and problems for students and researchers, along with numerous examples and case studies for practicing engineers seeking solutions to real-world problems.

Julien, Pierre Y.

1998-03-01

339

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

340

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

341

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

342

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

343

EPRI condenser-related research projects  

SciTech Connect

This report summarizes all recently completed and current EPRI research projects that relate to steam surface condensers in both fossil-fuel and nuclear power plants, as well as new projects planned through 1983. The project summaries are organized into sections according to type of issue addressed. The first section reports upon general projects that identify causes of condenser failures. Following sections deal with air and water inleakage control, erosion-corrosion control, leak detecton, bifouling and scaling, engineering design, nondestructive evaluation (NDE) techniques, the special issues of closed-cycle cooling systems, and technology transfer efforts. In all, 54 projects are reported upon. This report was issued by EPRI's Condenser Research Coordinating Committee, the members of which are the technical staff responsible for condenser-related research. Projects are funded separately by several different divisions and groups within EPRI; the coordinating committee is responsible for the coordination of these projects and for long-range project planning.

Laliberte, M.

1983-11-01

344

Fast Affine Projection Algorithms for Filtered-x Multichannel Active Noise Control  

Microsoft Academic Search

In recent years, affine projection algorithms have been proposed for adaptive system applications as an efficient alternative to the slow convergence speed of least mean square (LMS)-type algorithms. Whereas much attention has been focused on the development of efficient versions of affine projection algorithms for echo cancellation applications, the similar adaptive problem presented by active noise control (ANC) systems has

Miguel Ferrer; Alberto Gonzalez; Maria De Diego; Gema Pinero

2008-01-01

345

The VIKING project: An initiative on resilient control of power networks  

Microsoft Academic Search

This paper presents the work on resilient and secure power transmission and distribution developed within the VIKING (vital infrastructure, networks, information and control system management) project. VIKING receives funding from the European Community's Seventh Framework Program. We will present the consortium, the motivation behind this research, the main objective of the project together with the current status.

Annarita Giani; Shankar Sastry; Karl H. Johansson; Henrik Sandberg

2009-01-01

346

Maximum Entropy/Optimal Projection (MEOP) Control Design Synthesis: Optimal Quantification of the Major Design Tradeoffs.  

National Technical Information Service (NTIS)

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...

D. C. Hyland D. S. Bernstein

1987-01-01

347

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

348

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...

349

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

350

EVALUATION OF CONTROL ROD MATERIALS CVTR PROJECT. Terminal Report  

Microsoft Academic Search

Mechanical and corrosion tests were performed on various control rod ; materials for CVTR application. The corrosion tests were carried out in ; demineralized static-water at 190 deg F and in a helium-water vapor atmosphere at ; 530 deg F. The mechanical tests were carried out at room temperature and at 250 ; deg F. The tests indicated that either

L. Marti-Balaguer; W. R. Smalley

1960-01-01

351

Behavior Modification Project: Reducing and Controlling Calling Out Behaviors.  

ERIC Educational Resources Information Center

The purpose of this study was to determine which behavior modification procedures were the most effective in reducing and controlling the inappropriate calling out behavior of a fifth-grade socially and emotionally disturbed student. Three phases of interventions were involved. As the study began, the resource room instructor was using a behavior…

James, Deborah Anne

352

Homotopy Algorithm for Digital Optimal Projection Control Gasd-Hadoc.  

National Technical Information Service (NTIS)

The linear-quadratic-gaussian (LQG) compensator was developed to facilitate the design of control laws for multi-input, multi-output (MIMO) systems. The compensator is computed by solving two algebraic equations for which standard closed-loop solutions ex...

E. G. Collins S. Richter L. D. Davis

1993-01-01

353

A Quality Control System for Curriculum-Based CBI Projects.  

ERIC Educational Resources Information Center

Describes a quality control system for a curriculum-based, computer-based instruction (CBI) program that was developed by Florida State University's Center for Educational Technology (CET) for the U. S. Army's Job Skills Education Program (JSEP). Flow charts are presented and explained for each stage of the system. (six references) (LRW)

Darabi, G. Abbas; Dempsey, John V.

1990-01-01

354

Athens automation and control experiment project review meeting, Knoxville, Tennessee, December 3-5, 1985  

SciTech Connect

The AACE is an electric power distribution automation project involving research and development of both hardware and software. Equipment for the project is being installed on the electric distribution system in Athens, Tennessee. Purposes of the AACE are to develop and test load control, volt/var control, and system reconfiguration capabilities on an electric distribution system and to transfer what is learned to the electric utility industry. Expected benefits include deferral of costly power generation plants and increased electric service reliability.

Braithwait, S.D.; Broadaway, E.R.; Fortson, N.D.; Gellings, C.W.; Hu, P.S.; Lawler, J.S.; Markel, L.C.; McKinley, K.F.; Monteen, L.D.; Newton, B.K.

1986-08-01

355

Applications of quality assurance\\/quality control concepts to non-hardware project management  

Microsoft Academic Search

The concepts of Quality Assurance and Quality Control, developed over 40 years ago for high quantity production of hardware, are now routinely and effectively applied to complex, one-of-a-kind projects such as design and construction of nuclear power plants. Currently, Quality Assurance and Quality Control are being applied to projects where outputs are less tangible, e.g., software, services, technical judgements. To

Calek

1979-01-01

356

Project Orion, Environmental Control and Life Support System Integrated Studies  

NASA Technical Reports Server (NTRS)

Orion is the next vehicle for human space travel. Humans will be sustained in space by the Orion subystem, environmental control and life support (ECLS). The ECLS concept at the subsystem level is outlined by function and technology. In the past two years, the interface definition with other subsystems has increased through different integrated studies. The paper presents the key requirements and discusses three recent studies (e.g., unpressurized cargo) along with the respective impacts on the ECLS design moving forward.

Russell, James F.; Lewis, John F.

2008-01-01

357

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

358

FEM analysis of erosive wear  

Microsoft Academic Search

Surface damage caused by the impact of dispersed particles in gas or liquid flow is called “erosion”. Much attention has been paid to this phenomenon as one of the most serious problems to be solved, particularly concerning pipe-bends or valves in pneumatic conveying systems. But the phenomena of erosive wear are so complicated and vary depending on the factors of

K. Shimizu; T. Noguchi; H. Seitoh; M. Okada; Y. Matsubara

2001-01-01

359

Mesh erosion after abdominal sacrocolpopexy  

Microsoft Academic Search

Objective: To report our experience with erosion of permanent suture or mesh material after abdominal sacrocolpopexy.Methods: A retrospective chart review was performed to identify patients who underwent sacrocolpopexy by the same surgeon over 8 years. Demographic data, operative notes, hospital records, and office charts were reviewed after sacrocolpopexy. Patients with erosion of either suture or mesh were treated initially with

Neeraj Kohli; Peggy M Walsh; Todd W Roat; Mickey M Karram

1998-01-01

360

Rangeland Hydrology and Erosion Model  

NASA Astrophysics Data System (ADS)

Soil loss rates on rangelands are considered one of the few quantitative indicators for assessing rangeland health and conservation practice effectiveness. An erosion model to predict soil loss specific for rangeland applications has been needed for many years. Most erosion models were developed from croplands where the hydrologic and erosion processes are different, largely due to much higher levels of heterogeneity in soil and plant properties at the plot scale and the consolidated nature of the soils. The Rangeland Hydrology and Erosion Model (RHEM) was designed to fill that need. RHEM is an event-based model that estimates runoff, erosion, and sediment delivery rates and volumes at the spatial scale of the hillslope and the temporal scale of a single rainfall event. It represents erosion processes under normal and fire-impacted rangeland conditions, it adopts a new splash erosion and thin sheet-flow transport equation developed from rangeland data, and it links the model hydrologic and erosion parameters with rangeland plant communities by providing a new system of parameter estimation equations based on 204 plots at 49 rangeland sites distributed across 15 western U.S. states. Recent work on the model is focused on representing intra-storm dynamics, using stream-power as the driver for detachment by flow, and deriving parameters for after-fire conditions.

Nearing, Mark; Pierson, Fred; Hernandez, Mariano; Al-Hamdan, Osama; Weltz, Mark; Spaeth, Ken; Wei, Haiyan; Stone, Jeff

2013-04-01

361

Nocturnal lagophthalmos and recurrent erosion  

Microsoft Academic Search

The symptoms and corneal changes caused by sleeping with one or both eyes open are described in 102 patients. The clinical picture is identical to that of the microform recurrent erosion. The close relationship between the micro- and macro-forms of recurrent corneal erosion suggests that the latter condition is also precipitated by nocturnal lagophthalmos.

G. D. Sturrock

1976-01-01

362

Projection screen reflectance control for high contrast display using photochromic compounds and UV LEDs.  

PubMed

This paper presents the first proof-of-concept implementation and the principle that realizes a projection display whose contrast does not decrease even with existing inter-reflection of projection light or environmental light. We propose the use of photochromic compounds (PhC) to control reflectance of a projection surface. PhC changes color chemically when exposed to UV light. A PhC is applied to a surface to control its reflectance by radiating UV light from a UV-LED array. An image is projected from a visible projector onto the surface to boost the contrast. The proof-of-concept experiment shows that the prototype system achieves approximately three times higher contrast than a projection-only system under natural light. PMID:24921543

Iwai, Daisuke; Takeda, Shoichi; Hino, Naoto; Sato, Kosuke

2014-06-01

363

Hexapartite safeguards project team 3: material accounting and control questionnaire  

SciTech Connect

Information provided in this report reflects the current design and operating procedures for the GCEP. However, since the installation is currently under construction, facility design and operating procedures discussed in this report are subject to change. Where applicable, the responses are based on material control and accounting practices of the Portsmouth Gaseous Diffusion Plant's (GDP) operating contractor (Goodyear Atomic Corporation). These practices meet US Department of Energy (DOE) standards and are assumed to be the reference practices for the GCEP. This report covers data collection and record keeping actions of the operator.

Swindle, D.W. Jr.

1981-06-16

364

Muddy Waters: Soil Erosion and Downstream Externalities  

Microsoft Academic Search

Soil erosion and fertilizer run-off cause serious flow externalities in downstream environments through-out the world. Social costs include e.g. loss of health, life and production due to pollution and eutrophication of freshwater resources, reduced life of hydro-power plants, increased turbidity, and degradation of coral reefs and marine resources. The key optimal control models on soil capital management omit downstream externalities

Anders Ekbom; Gardner M. Brown; Thomas Sterner

2009-01-01

365

Soil erosion and sediment yield prediction on catchment and regional scale using a process based simulation model  

NASA Astrophysics Data System (ADS)

The prevention of erosion is one of the main issues in the EU-Water Framework Directive (WFD) and the European Agricultural Fund for Rural Development (EAFRD). Planning and dimensioning of soil conservation measures require reliable and detailed information on the temporal and spatial distribution of soil detachment, soil transport and deposition. Soil erosion models are increasingly used, in order to simulate the physical processes involved and to predict the effects of soil erosion control measures. In this study the EROSION 3D simulation model is used for surveying soil erosion and deposition on the catchment scale covering the entire state of Saxony/Germany (18.500 km²). EROSION 3D is a distributed, extensively validated GIS based soil loss and deposition model including sediment delivery to surface water bodies. However, the application of the model for an entire state is a new challenge, because of the enormous data requirements and complex data processing operations prior to simulation. In this context the study includes the compilation, validation and generalisation of existing land use and soil data in order to generate a consistent EROSION 3D input dataset for the entire state of Saxony. As a part of this process the interface software DPROC allows to transfer the original soil and land use data into model specific data. The project aims to extend the interface software DPROC by an interactive GIS-component which enables the user to select arbitrary hydrological watersheds including the related soil and land use data. Based on these data DPROC automatically creates the according EROSION 3D input files using a relational database of primary data and model specific data. DPROC uses parameter transfer tables in order to specify the relationship between primary soil and land use data and model specific data. This combined methodology provides different risk assessment maps for certain demands on the regional scale of a Federal State. Besides soil loss and sediment transport sediment pass over points into surface water bodies and particle enrichment can be simulated using the EROSION 3D model. Thus the estimation of particle bound nutrient and pollutant inputs into surface water bodies according to the WFD demands is possible. The study ended up in a user-friendly, timesaving and improved software package for the simulation of soil loss and deposition on a regional scale providing essential information for the planning of soil and water conservation measures particularly under consideration of expected land use and climate changes.

Schindewolf, Marcus; Schmidt, Jürgen

2010-05-01

366

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

367

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

368

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

369

Erosion--corrosion  

SciTech Connect

The deterioration of materials by corrosion or erosion by itself presents a formidable problem and for this reason investigators have studied these two phenomena independently. In fact, there are very few systematic studies on E-C and the majority of references mention it only in passing. In most real systems, however, the two destructive processes take place simultaneously, hence the purpose of this review is to present the various interactions between the chemical and mechanical agents leading to accelerated degradation of the material. The papers cited in the review are those that lead to a better understanding of the process involved in the accelerated rate of material loss under E-C conditions.

Vyas, B.

1978-01-01

370

Excitatory Projection Neuron Subtypes Differentially Control the Distribution of Local Inhibitory Interneurons in the Cerebral Cortex  

PubMed Central

In the mammalian cerebral cortex, the developmental events governing the integration of excitatory projection neurons and inhibitory interneurons into balanced local circuitry are poorly understood. We report that different subtypes of projection neurons uniquely and differentially determine the laminar distribution of cortical interneurons. We find that in Fezf2?/? cortex, the exclusive absence of subcerebral projection neurons and their replacement by callosal projection neurons cause distinctly abnormal lamination of interneurons and altered GABAergic inhibition. In addition, experimental generation of either corticofugal neurons or callosal neurons below the cortex is sufficient to recruit cortical interneurons to these ectopic locations. Strikingly, the identity of the projection neurons generated, rather than strictly their birthdate, determines the specific types of interneurons recruited. These data demonstrate that in the neocortex individual populations of projection neurons cell-extrinsically control the laminar fate of interneurons and the assembly of local inhibitory circuitry.

Lodato, Simona; Rouaux, Caroline; Quast, Kathleen B.; Jantrachotechatchawan, Chanati; Studer, Michele; Hensch, Takao K.; Arlotta, Paola

2011-01-01

371

A revealed preference approach to estimating supply curves for ecosystem services: use of auctions to set payments for soil erosion control in Indonesia.  

PubMed

To supply ecosystem services, private landholders incur costs. Knowledge of these costs is critical for the design of conservation-payment programs. Estimating these costs accurately is difficult because the minimum acceptable payment to a potential supplier is private information. We describe how an auction of payment contracts can be designed to elicit this information during the design phase of a conservation-payment program. With an estimate of the ecosystem-service supply curve from a pilot auction, conservation planners can explore the financial, ecological, and socioeconomic consequences of alternative scaled-up programs. We demonstrate the potential of our approach in Indonesia, where soil erosion on coffee farms generates downstream ecological and economic costs. Bid data from a small-scale, uniform-price auction for soil-conservation contracts allowed estimates of the costs of a scaled-up program, the gain from integrating biophysical and economic data to target contracts, and the trade-offs between poverty alleviation and supply of ecosystem services. Our study illustrates an auction-based approach to revealing private information about the costs of supplying ecosystem services. Such information can improve the design of programs devised to protect and enhance ecosystem services. PMID:18983597

Jack, B Kelsey; Leimona, Beria; Ferraro, Paul J

2009-04-01

372

Reduction of Gun Erosion and Correlation of Gun Erosion Measurements  

NASA Technical Reports Server (NTRS)

Gun barrel erosion is serious problem with two-stage light gas guns. Excessive barrel erosion can lead to poor or failed launches and frequent barrel changes, with the corresponding down time. Also, excessive barrel erosion can limit the maximum velocity obtainable by loading down the hydrogen working gas with eroded barrel material. Guided by a CFD code, the operating conditions of the Ames 0.5-inch gun were modified to reduce barrel erosion. The changes implemented included: (1) reduction in the piston mass, powder mass and hydrogen fill pressure; and (2) reduction in pump tube volume, while maintaining hydrogen mass. The latter change was found, in particular, to greatly reduce barrel erosion. For muzzle velocity ranges of 6.1 - 6.9 km/sec, the barrel erosion was reduced by a factor of 10. Even for the higher muzzle velocity range of 7.0 - 8.2 km/sec, the barrel erosion was reduced by a factor of 4. Gun erosion data from the Ames 0.5-inch, 1.0-inch, and 1.5-inch guns operated over a wide variety of launch conditions was examined and it was found that this data could be correlated using four different parameters: normalized powder charge energy, normalized hydrogen energy density, normalized pump tube volume and barrel diameter. The development of the correlation and the steps used to collapse the experimental data are presented. Over a certain parameter range in the correlation developed, the barrel erosion per shot is found to increase very rapidly. The correlation should prove useful in the selection of gun operating conditions and the design of new guns. Representative shapes of eroded gun barrels are also presented.

Bogdanoff, Dave; Wercinski, Paul (Technical Monitor)

1997-01-01

373

Teaching about Hazard Identification and Injury Control: A Student-Based Project Focusing on Pedestrian Safety.  

ERIC Educational Resources Information Center

Students learn to practice safe behavior most effectively when they are actively involved in the process of identifying and controlling hazards. This article focuses on a problem faced by many urban-based schools--pedestrian safety. Hazard identification projects can be used to train students to develop practical, effective hazard controls. The…

Wojtowicz, G. Greg; DesLauriers, Karen

374

Combating Tropical Infectious Diseases: Report of the Disease Control Priorities in Developing Countries Project  

Microsoft Academic Search

Infectious diseases are responsible for 125% 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 demo- graphic, epidemiologic, disease intervention, and economic evidence for the purpose of defining disease priorities and im- plementing control measures. The DCPP recently reviewed selected tropical

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

2004-01-01

375

CRCS\\/CCS: An integrated probabilistic construction cost control approach for highway project  

Microsoft Academic Search

The recent focus on improving the performance of construction cost control for highway project in China has led to a demand from industry for approaches that can cope with increasing complexity. Whilst many existing research now providing the methods to control for deviation from cost standards after finding cost variance, other factors such as component cost risk are still widely

Weiyi He; Yilin Yin

2010-01-01

376

Multi-Canister overpack pressurization monitoring and control methodology for the spent nuclear fuel project  

SciTech Connect

A control methodology is developed and monitoring alternatives evaluated for controlling pressurization in a Multi- Canister Overpack for the Hanford Spent Nuclear Fuel Project. Monitoring alternative evaluations include concept description, identification of uncertainties, and identification of experimental work required for implementation. A monitoring alternative is recommended and implementation requirements, risks and start up testing associated with the recommendation are discussed.

Pajunen, A.L., Westinghouse Hanford

1996-07-19

377

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.

Edited by Barnhardt, W. A.

2009-01-01

378

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

379

Tropical volcanic islands: best first cycle erosion laboratories.  

NASA Astrophysics Data System (ADS)

Lesser Antilles islands are located in a tropical climate with high temperatures (24 to 28 ° C), high precipitation (can reach 12 m/yr), very dense vegetation, sharp relief with a NS gradient of age. Antilles rivers have a torrential hydrologic regime with extreme erosion conditions. Chemical weathering rates are among highest world values 140-200 t/km2/yr on surface and 2 to 5 time higher when subsurface water circulations are taken account (Rad et al., 2007). Timescales and physical rates of erosion are calculated from U-Th isotopic compositions. Our results, with 3 different methods (all based on mass budgets between the river bedrock and its erosion products) show a good agreement for physical erosion rates with a maximum value of 2500 t/km2/yr. We show that solid loads of these volcanic rivers are dominated by sand, which represent more than 80% of the soil profile. Erosion rates are directly correlated to the age of basins. Indeed, among all parameters (climat, runoff, slopes, vegetation...) the age basins is a key control parameter. The younger the basin is the higher the weathering rate is. This correlation asserts that younger volcanic rocks are more easily weathered than old ones: young fresh material is easily mobilized by erosion, while for older rocks with thick soil covers, chemical and physical erosion rates are much lower, they reach a threshold with low chemical and physical rates once soils are constituted. It seems that rivers draining young lava flows are also the ones, which are not at steady state with the lowest mechanical denudation rates. Erosion processes in Lesser Antilles are typical of a first cycle erosion with simple relationship between rates, timescale of erosion and basins ages. It appears that first stage of erosion are characterized by high chemical denudation rates and low physical denudation rates, the erosion products are then close to the bedrock. It is then followed in a second stage by constant chemical weathering rates with higher mechanical denudation rates. \\small Setareh Denise Rad, Claude Jean Allegre and Pascale Louvat, 2007, Hidden erosion on volcanic islands, Earth and Planetary Science Letters. In Press.

Rad, S.; Rive, K.; Gaillardet, J.; Allegre, C. J.

2007-12-01

380

DOE/EA-1493: Environmental Assessment for Greenidge Multi-Pollutant Control Project (August 2004)  

SciTech Connect

DOE has prepared an Environmental Assessment (EA), DOE/EA-1493, titled ''Greenidge Multi-Pollutant Control Project'', to analyze the potential environmental consequences of providing cost-shared funding support for the design, construction, and demonstration of an integrated multipollutant control system at AES's Greenidge Station in Dresden, New York. The system, expected to control emissions of NO{sub x}, SO{sub 2}, SO{sub 3}, HF, HCl, and Hg, would be installed on the existing, coal-fired, 107-MW Unit 4 at Greenidge. The results of the analyses provided in the EA are summarized in this Finding of No Significant Impact. The proposed action is for DOE to provide about $14.5 million for this project, while CONSOL Energy Inc. and its project partners would be responsible for the remaining $21 million. The proposed project will result in technical, environmental, and financial data from the design, operation and construction of the multi-pollutant control system. This 4.5-year, commercial-scale demonstration project would allow utilities, particularly those with units less than 300-MW in capacity, to make decisions regarding the integrated multi-pollutant control system as a viable commercial option. Based on the analyses in the EA, DOE has concluded that the Greenidge Multi-Pollutant Control Project would result in minimal and insignificant consequences to the human environment. Thus, DOE considers that the proposed action, providing cost-shared funding for the project, is not a major Federal action significantly affecting the quality of the human environment, within the meaning of the National Environmental Policy Act (NEPA) of 1969, 42 United States Code 4321, et seq. Therefore, in accordance with 10 CFR Part 1021.322, DOE has concluded that preparation of an Environmental Impact Statement is not required, and DOE is issuing this FONSI.

N /A

2004-08-10

381

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.

382

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

383

Gastroesophageal Reflux Disease and Tooth Erosion  

PubMed Central

The increasing prevalence of gastroesophageal reflux disease (GERD) in children and adults, and of “silent refluxers” in particular, increases the responsibility of dentists to be alert to this potentially severe condition when observing unexplained instances of tooth erosion. Although gastroesophageal reflux is a normal physiologic occurrence, excessive gastric and duodenal regurgitation combined with a decrease in normal protective mechanisms, including an adequate production of saliva, may result in many esophageal and extraesophageal adverse conditions. Sleep-related GERD is particularly insidious as the supine position enhances the proximal migration of gastric contents, and normal saliva production is much reduced. Gastric acid will displace saliva easily from tooth surfaces, and proteolytic pepsin will remove protective dental pellicle. Though increasing evidence of associations between GERD and tooth erosion has been shown in both animal and human studies, relatively few clinical studies have been carried out under controlled trial conditions. Suspicion of an endogenous source of acid being associated with observed tooth erosion requires medical referral and management of the patient as the primary method for its prevention and control.

Ranjitkar, Sarbin; Kaidonis, John A.; Smales, Roger J.

2012-01-01

384

Patterns of glacial erosion affected by initial topography  

NASA Astrophysics Data System (ADS)

Spatial and temporal variations in glacial erosion patterns are generally difficult to unravel on longer timescales. Methods constraining glacial erosion rates have proven very dependent on the timescales on which they work, and long-term measures are often accompanied with a lack of temporal detail. In addition, numerical approaches simulating glacial erosion are often forced to choose between either spatial or temporal resolution due to extensive computational costs. The linking of observations and numerical modeling results is complicated further by the fact that the initial pre-glacial landscape is often poorly constrained. This poses significant challenges when considering the topographic control there exists on ice flow and glacier sliding. Here we investigate the effect of the initial pre-glacial topography on patterns of glacial erosion using numerical modeling. We investigate 1) characteristic glacial sliding patterns when simulating glacial conditions in high-resolution landscapes for a number of characteristic natural settings including wedge-type topography and plateau-type topography, and 2) high-resolution long-term patterns of glacial erosion for characteristic landscapes. In order to accomplish this latter part, we use spatially constricted generic models, designed to capture the long-term evolution of glacial landscapes over multiple glacial-interglacial cycles at high spatial resolution. Studies examining glacial erosion processes often use either an existing present-day landscape or a reconstructed fluvial steady-state configuration. However, it is important to investigate the effect of initial pre-glacial topography on patterns of glacial erosion, as fluvial steady state is not often found to occur. Glacial erosion patterns therefore need to be understood in the context of the pre-existing topography when trying to link observations of glacial erosion rates and long-term landscape evolution.

Kathrine Pedersen, Vivi; Huismans, Ritske

2013-04-01

385

Savannah River Site 1991 Road Erosion Inventory.  

SciTech Connect

Final Report. USDA Forest Service, Savannah River, Aiken, SC. 28 pp. Abstract - This paper explains the rationale and results of a 1991 road erosion inventory conducted by members of the USDA Forest Service – Savannah River (FS-SR) and USDA Natural Resources Conservation Service (NRCS). The inventory provided information for the Department of Energy - Savannah River (DOE-SR) to justify the need for developing an erosion and sediment control program with appropriate funding, personnel, and equipment. Federally managed since the early 1950’s, the SRS is located on 198,344 acres (80,301 hectares) in the South Carolina counties of Aiken, Barnwell, and Allendale. Located along the eastern border of the Savannah River, the SRS is located within the Upper and Lower Coastal Plains of South Carolina.

Jones, Cliff.

2007-06-22

386

[Therapeutic strategies in erosive digital polyarthrosis].  

PubMed

One of the most common forms of osteoarthritis is hand osteoarthritis. A subgroup, termed erosive hand osteoarthritis (EHOA), shows a highly destructive disease course with involvement of multiple joints, swelling as well as cartilage and bone destruction leading to progressive loss of hand function. EHOA is characterized by subchondral erosions of the finger joints as well as ankylosis. No disease modifying therapy is currently available for the treatment of EHOA and treatment options are confined to the control of symptoms. Acetaminophen and non-steroidal anti-inflammatory drugs are used to treat the signs and symptoms. So far cytokine blocking agents have not shown a convincing therapeutic effect and the effect size of chondroitin sulfate and bisphosphonates in EOHA is small. PMID:21523453

Sahinbegovic, E; Schett, G

2011-06-01

387

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

388

Cavitation erosion size scale effects  

NASA Technical Reports Server (NTRS)

Size scaling in cavitation erosion is a major problem confronting the design engineers of modern high speed machinery. An overview and erosion data analysis presented in this paper indicate that the size scale exponent n in the erosion rate relationship as a function of the size or diameter can vary from 1.7 to 4.9 depending on the type of device used. There is, however, a general agreement as to the values of n if the correlations are made with constant cavitation number.

Rao, P. V.; Buckley, D. H.

1984-01-01

389

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

390

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

391

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

392

Joint power and multiple access control for wireless mesh network with rose projection method.  

PubMed

This paper investigates the utility maximization problem for the downlink of the multi-interface multichannel wireless mesh network with orthogonal frequency division multiple access. A cross-layer joint power and multiple access control algorithm are proposed. Rosen projection matrix is combined with Solodov projection techniques to build a three-memory gradient Rosen projection method, which is applied to solve this optimization problem. The convergence analysis is given and simulations show that the proposed solution achieves significant throughput compared with existing approaches. PMID:24883384

Tang, Meiqin; Shang, Lili; Xin, Yalin; Liu, Xiaohua; Wei, Xinjiang

2014-01-01

393

Joint Power and Multiple Access Control for Wireless Mesh Network with Rose Projection Method  

PubMed Central

This paper investigates the utility maximization problem for the downlink of the multi-interface multichannel wireless mesh network with orthogonal frequency division multiple access. A cross-layer joint power and multiple access control algorithm are proposed. Rosen projection matrix is combined with Solodov projection techniques to build a three-memory gradient Rosen projection method, which is applied to solve this optimization problem. The convergence analysis is given and simulations show that the proposed solution achieves significant throughput compared with existing approaches.

Tang, Meiqin; Shang, Lili; Xin, Yalin; Liu, Xiaohua; Wei, Xinjiang

2014-01-01

394

Monitoring of gully erosion in the Central Ebro Basin by large-scale aerial photography taken from a remotely controlled blimp  

Microsoft Academic Search

Large deep gullies (Span. barrancos) are some of the most important sediment sources in the semi-arid environment of the Central Ebro Basin. They are incised into the Quaternary valley bottoms (Span. vales), which are characteristic landforms in this area. In the research project EPRODESERT (Evaluation of Processes Leading to Land Degradation and Desertification under Extensified Farming Systems), the development of

J. B. Ries; I. Marzolff

2003-01-01

395

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

396

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

397

MPD thruster erosion research  

NASA Astrophysics Data System (ADS)

The multimegawatt MPD (Magnetoplasma Dynamic) thruster is an electric engine capable of orbital transfer and maneuvering of large payloads driven by a megawatt class space power supply. The MPD thruster is capable of specific impulses from 1,500 to 8,000 s. The high specific impulse means this system can perform missions using much less propellant than chemical systems. A five MW MPD electric system, propellant and payload from one shuttle launch must be replaced by the equivalent of four fully loaded Centaur G' stages. Thus, the savings in propellant and launch costs are very substantial. This report discusses 3 aspects of MPD thruster Physics: (1) A significant operational problem which has limited the useful operation of the device is discussed. This is severe erosion of the insulator at the cathode insulator junction. A technique which appears to solve the problem has been tested, and is described. (2) A preliminary analyses of anode sheath is presented. (3) Analysis of the discharges two dimensional nature is explored for the case where transverse gradients are considered but transverse velocity is assumed to be zero. This situation applies to high aspect ratio devices. The analyses concludes with a formalism that provides a means to qualitatively evaluate Ohmic dissipation from simple measurements of magnetic Hall effect on magnetosonic choking (where thermodynamics is ignored).

King, David Q.; Callas, John L.

1988-11-01

398

New projection optics and aberration control system for the 45-nm node  

NASA Astrophysics Data System (ADS)

The 65nm and the subsequent 45nm node lithography require very stringent CD control. To realize high-accuracy CD control on an exposure tool, it is essential to reduce wavefront aberrations induced by projection optics design and manufacturing errors and then stabilize the aberrations while the exposure tool is in operation. We have developed two types of new hyper-NA ArF projection optics to integrate into our new platform exposure tool: a dry system and a catadioptric system for immersion application. In this paper, aberration measurement results of these projection systems are shown, demonstrating that ultra-low aberration is realized. In addition, a new projection optical system has been developed which incorporates high degree-of-freedom Aberration Controllers and automatic aberration measuring sensors. These controllers and sensors are linked together through Aberration Solver, a software program to determine optimal target values for aberration correction, thereby allowing the projection optics to maintain its best optical properties. The system offers excellent performance in correcting aberrations that come from lens heating, and makes it possible to guarantee extremely low aberrations during operation of the exposure tool.

Yoshihara, Toshiyuki; Takeshita, Bunsuke; Shigenobu, Atsushi; Hasegawa, Yasuo; Ohsaki, Yoshinori; Mishima, Kazuhiko; Miura, Seiya

2007-03-01

399

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

400

erosion Behavior of Liquid Lithium  

NASA Astrophysics Data System (ADS)

The erosion rates of both solid and liquid lithium samples exposed to plasma bombardment have been studied in PISCES-B. Measurements of the erosion rate of solid samples, while consistent with measurements from other facilities, are an order of magnitude less than the predictions from the TRIM Monte-Carlo sputtering code. The temperature dependence of the erosion yield from liquid samples exhibits an enhancement beyond that expected from a combination of physical sputtering and evaporation. The onset of the enhanced erosion coincides with a decrease in the ejection energy of particles from the sample, indicating that the enhancement is due to an increase in sublimation of the sample. The possibility that thermal spikes resulting from the low-energy ion bombardment (<200 eV) may be responsible for the increase in evaporation from the surface will be discussed.

Doerner, R. P.; Krasheninnikov, S.; Whyte, D. G.; Baldwin, M.; Luckhardt, S.; Seraydarian, R. P.; Conn, R. W.

2001-10-01

401

Erosion in Large Gun Barrels.  

National Technical Information Service (NTIS)

The erosion of gun tubes is a very complex interdisciplinary problem involving several branches of engineering and science. Several mechanisms are responsible for this limitation to gun tube life, some of which are of thermal origin, some are mechanical a...

1975-01-01

402

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

403

ERIP Project No. 670, Nevada Energy Control Systems, Inc.. Final techincal progress report  

SciTech Connect

In order to gauge the effectiveness of the ERIP Project No. 670, Nevada Energy Control Systems, Inc., Grant Number DE-FG01-96EE15670, the Statement of Work must be compared to the achievements by NECSI during the grant period. The following report reflects the aforementioned statement and is coordinated directly with it. The project goal is to gather data and test in order to validate earlier tests of energy savings,safety,reliability and practicality of the NECSI Evaporator Fan Controller in order to fully commercialize and market the product.

Kimber, D.J.

1998-02-11

404

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.

405

Agriculture and Soil Erosion in the Ohio River Basin.  

National Technical Information Service (NTIS)

The primary purpose of the USDA study, 'Land Use and Sheet and Rill Soil Loss Estimates, Ohio River Basin - 1974, 2000, and 2000P,' December 1979, was to estimate existing and projected soil erosion. Since ninety percent of the Ohio River Basin land is de...

1981-01-01

406

Lithosphere erosion atop mantle plumes  

NASA Astrophysics Data System (ADS)

Mantle plumes are traditionally proposed to play an important role in lithosphere erosion. Seismic images beneath Hawaii and Cape Verde show a lithosphere-asthenosphere-boundary (LAB) up to 50 km shallower than the surroundings. However, numerical models show that unless the plate is stationary the thermo-mechanical erosion of the lithosphere does not exceed 30 km. We use 2D petrological-thermo-mechanical numerical models based on a finite-difference method on a staggered grid and marker in cell method to study the role of partial melting on the plume-lithosphere interaction. A homogeneous peridotite composition with a Newtonian temperature- and pressure-dependent viscosity is used to simulate both the plate and the convective mantle. A constant velocity, ranging from 5 to 12.5 cm/yr, is imposed at the top of the plate. Plumes are created by imposing a thermal anomaly of 150 to 350 K on a 50 km wide domain at the base of the model (700 km depth); the plate right above the thermal anomaly is 40 Myr old. Partial melting is modeled using batch-melting solidus and liquidus in anhydrous conditions. We model the progressive depletion of peridotite and its effect on partial melting by assuming that the melting degree only strictly increases through time. Melt is accumulated until a porosity threshold is reached and the melt in excess is then extracted. The rheology of the partially molten peridotite is determined using viscous constitutive relationship based on a contiguity model, which enables to take into account the effects of grain-scale melt distribution. Above a threshold of 1%, melt is instantaneously extracted. The density varies as a function of partial melting degree and extraction. Besides, we analyze the kinematics of the plume as it impacts a moving plate, the dynamics of time-dependent small-scale convection (SSC) instabilities developing in the low-viscosity layer formed by spreading of hot plume material at the lithosphere base, and the resulting thermal rejuvenation of the lithosphere. The onset time and the vigor of SSC and, hence, the new equilibrium thermal state of the lithosphere atop the plume wake depends on the Rayleigh number (Ra) in the unstable layer at the base of the lithosphere, which is controlled by the temperature anomaly and rheology in the plume-fed layer. For vigorous, hot plumes, SSC onset times do not depend on plate velocity. For more sluggish plumes, SSC onset times decrease with increasing plate velocity. This behavior is explained by differences in the thermal structure of the lithosphere, due to variations in the spreading behavior of the plume material at the lithosphere base. Reduction of the viscosity in partial molten areas and decrease in density of the depleted residuum enhance the vigor of small-scale convection in the plume-fed low-viscosity layer at the lithosphere base, leading to more effective erosion of the base of the lithosphere.

Agrusta, R.; Arcay, D.; Tommasi, A.

2012-12-01

407

The global control of silicate weathering rates and the coupling with physical erosion: new insights from rivers of the Canadian Shield  

Microsoft Academic Search

The chemical evolution of the surface of the Earth is controlled by the interaction of rainwaters, the atmosphere and the continental crust. That is the main reason why the knowledge of the parameters that control chemical denudation on Earth is of crucial importance. We report chemical and isotopic analyses for river waters from the Canadian Shield in order to estimate

Romain Millot; Jérôme Gaillardet; Bernard Dupré; Claude Jean Allègre

2002-01-01

408

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.

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

2012-01-01

409

The interaction between soil erosion and soil organisms in temperate agroecosystems: nematode redistribution in tramlines  

NASA Astrophysics Data System (ADS)

Arable agriculture presents a unique set of challenges, and one of the most important is soil erosion. Whilst policy and practice look towards sustainable intensification of production to ensure food security, fundamental gaps in our understanding still exist. The physical processes involved in the detachment, transport and deposition of soil are well characterised but further research considering chemical and nutrient transport, fertiliser and pesticide losses, and environmental impacts to downstream environments is still required. Furthermore the interaction between soil erosion and soil organisms have largely been ignored, even though soil organisms serve a myriad of functions essential in the provision of soil ecosystem goods and services. Here we present the findings of a field-scale experiment into soil biotic redistribution undertaken at the James Hutton Institute's Balruddery Farm, Scotland (Link Tramlines Project XDW8001). Farm vehicle-tyre wheelings left in arable fields (tramlines) to enable crop spraying during the crop growth cycle have been identified as key transport pathways for sediment and associated nutrients. We tested the hypothesis that soil organisms were also transported by tramline erosion. During the winter of 2012/13 an experiment was undertaken to measure soil organism export from unbound hillslope plots subject to four different tramline treatments set out in a randomised block design. We used soil nematodes as a model organism as they are ubiquitous and sensitive to disturbance and an established indicator taxa of biological and physico-chemical changes in soil. Tramline treatments included a control tyre (conventional tractor tyre), a control tyre with a sown tramline, a low pressure tyre with sown tramline, and a control tyre with a spiked harrow. Post-event sampling of rainfall events was undertaken, and a range of variables measured in the laboratory. The spiked harrow treatment produced the greatest overall reductions in nematode export with 95% less nematodes exported, compared with the control treatment. We observed wholesale non-selective transport of all nematode trophic groups present in the soil. The findings of this experiment are twofold. Firstly, we demonstrate that soil organisms are transported by erosion processes and confirm that tramlines are key hydrological pathways. Secondly, we highlight practical on-farm solutions that have potential to decrease soil organism losses. These results provide important baseline information to improve our understanding of soil erosion impacts to the wider soil ecosystem. The results help to inform soil and water conservation measures for sustainable agriculture.

Baxter, Craig; Rowan, John S.; McKenzie, Blair M.; Neilson, Roy

2014-05-01

410

Control Implications in Tracking Moving Objects Using Time-Varying Perspective-Projective Imagery  

Microsoft Academic Search

Control implications which arise when tracking moving objects contained in time-varying perspective-projective imagery are studied. First, a transformation is derived to relate pan\\/tilt camera mount movement to image plane perturbations. Ramifications of this model, particularly with respect to magnification ratio, noncentered targets and camera mount angular magnitudes are illustrated. A pan\\/tilt control algorithm is then developed using this transformation and

Karen A. Dzialo; Robert J. Schalkoff

1986-01-01

411

Feedback control of a solid-state qubit using high-fidelity projective measurement.  

PubMed

We demonstrate feedback control of a superconducting transmon qubit using discrete, projective measurement and conditional coherent driving. Feedback realizes a fast and deterministic qubit reset to a target state with 2.4% error averaged over input superposition states, and allows concatenating experiments more than 10 times faster than by passive initialization. This closed-loop qubit control is necessary for measurement-based protocols such as quantum error correction and teleportation. PMID:23368293

Ristè, D; Bultink, C C; Lehnert, K W; DiCarlo, L

2012-12-14

412

Advancement of global health: key messages from the Disease Control Priorities Project.  

PubMed

The Disease Control Priorities Project (DCPP), a joint project of the Fogarty International Center of the US National Institutes of Health, the WHO, and The World Bank, was launched in 2001 to identify policy changes and intervention strategies for the health problems of low-income and middle-income countries. Nearly 500 experts worldwide compiled and reviewed the scientific research on a broad range of diseases and conditions, the results of which are published this week. A major product of DCPP, Disease Control Priorities in Developing Countries, 2nd edition (DCP2), focuses on the assessment of the cost-effectiveness of health-improving strategies (or interventions) for the conditions responsible for the greatest burden of disease. DCP2 also examines crosscutting issues crucial to the delivery of quality health services, including the organisation, financial support, and capacity of health systems. Here, we summarise the key messages of the project. PMID:16616562

Laxminarayan, Ramanan; Mills, Anne J; Breman, Joel G; Measham, Anthony R; Alleyne, George; Claeson, Mariam; Jha, Prabhat; Musgrove, Philip; Chow, Jeffrey; Shahid-Salles, Sonbol; Jamison, Dean T

2006-04-01

413

Public Information Campaign: Soil Erosion, Conservation, and Watershed Health  

NSDL National Science Digital Library

Students in groups of two create a 4-minute educational video, brochure, and poster on an aspect of soil erosion, soil conservation, and/or watershed health for agricultural regions within the midwestern states. This is a half term project and the materials are presented in a forum towards the end of the semester. The project is aimed to help students learn to pitch science to a wide audience and provide practice (indirectly) applying scientific principles to conservation efforts.

Szramek, Kathryn

414

Statistical control of manufacturing cycle time and project time: lessons from statistical process control  

Microsoft Academic Search

A manufacturing cycle includes all activities from order processing to shipping. The benefits of reducing cycle time includes increased productivity and added competitive advantage. This paper proposes a new approach to the control of cycle time variability in the short-term and the reduction of cycle time in the long-term. It has been said that when the control and stability of

PAUL M. SWAMIDASS; CLYDE MAJERUS

1991-01-01

415

Technology Adoption Indicators Applied to the ATP Flow Control Machining Project.  

National Technical Information Service (NTIS)

In its 1995 General Competition, the Advanced Technology Program funded the Flow-Control Machining Project, a four-year $7.9 million research joint venture involving Extrude Hone Corporation, a small company in Irwin, PA, General Motors, the University of...

H. Brown M. Ehlen

2003-01-01

416

Experiences with industrial applications of projection methods for multivariate statistical process control  

Microsoft Academic Search

With process computers routinely collecting measurements on large numbers of process variables, multivariate statistical methods for the analysis, monitoring and diagnosis of process operating performance have received increasing attention. Recent approaches to multivariate statistical process control, which utilize not only the product quality data (as traditional approaches have done) but also the available process data, are based on multivariate projection

Theodora Kourti; Jennifer Lee; John F. Macgregor

1996-01-01

417

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.