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1

Shoveling in a materials world  

SciTech Connect

Shovels. How do you find the right one for your mine. Where do you start. Because capital costs for a fleet of shovels run into millions of dollars, proper planning can save you hundreds of thousands of dollars down the road. To help you make the most intelligent choice and use of these equipment resources, the authors analyzed ''electric'' shovels (also called cable shovels or wire rope shovels) and hydraulic shovels. This article is designed to answer those questions you may have concerning shovel selection, productivity, and operation.

Zaburunov, S.A.

1988-07-01

2

Smarter shovels dig and load more efficiently  

SciTech Connect

Digital drive upgrades allow older shovels to power through the bank smoothly while improving safety and reliability. Flanders Electric is currently working on the third of five electric shovel upgrades which consists of Flandex Electric manufactured motors, Allen-Bradley PLCs and the Power Performance Digital Drive upgrade. With an open system, or open architecture, mine operators can service and maintain machines where a close system would limit the electricians to work with the OEMs exclusively. Typically, upgrades replace the old analog or an older digital drive with a new Power Performance Digital Drive upgrade. 1 fig., 2 photos.

Fiscor, S.

2009-03-15

3

Plow Bodies for High Speed Plowing (Pluzhnye Korpusa dlya Skorostnoi Vspashki).  

National Technical Information Service (NTIS)

Studies were conducted on foreign and domestic plow bottoms to measure their draft resistance and range of operating speeds to determine the ones most suitable for high speed plowing. The bottoms tested initially were: (1) standard PLE-01, (2) high speed ...

E. D. Afonin N. L. Galiev

1972-01-01

4

4. Osgood steam shovel excavating roadway at Mormon Flat. Photographer ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. Osgood steam shovel excavating roadway at Mormon Flat. Photographer unknown, 1923. Source: Salt River Project. - Mormon Flat Dam, On Salt River, Eastern Maricopa County, east of Phoenix, Phoenix, Maricopa County, AZ

5

14. Photocopied August 1978. STEAM SHOVEL, SEPTEMBER 23, 1898. LOADING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Photocopied August 1978. STEAM SHOVEL, SEPTEMBER 23, 1898. LOADING ONE OF THE FIRST TRAINS OF DUMP CARS IN THE ROCK SECTION. (10) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

6

The Snow-Shoveler's ST Elevation Myocardial Infarction  

PubMed Central

Heavy snowfall, cold temperatures, and low atmospheric pressure during the winter months have been associated with increased adverse cardiovascular events. However, only a few cases of the “snow -shoveler’s infarction ” have been reported. We present our experience with 6 patients presenting with ST elevation myocardial infarction all within a 24-hour period during an unprecedented snowfall (4 of whom were shoveling snow), and provide a detailed review of previously reported cases of snow-shoveler’s infarction. Consistent with other reports, the majority of our patients had the traditional cardiac risk factors of hypertension, hyperlipidemia, diabetes mellitus, tobacco use, and were habitually sedentary. Unique to our case series, however, was that the four patients who had a history of coronary artery disease and prior coronary artery stenting, all presented with subacute stent thrombosis documented on the coronary angiography performed emergently. Moreover, these patients constituted 25% of all the subacute stent thromboses diagnosed in our cardiac catheterization laboratory over the preceding 12 months. In conclusion, our findings suggest that in typically sedentary individuals with cardiac risk factors or a history of coronary artery disease, snow shoveling may trigger ST elevation myocardial infarction and, therefore, should be avoided. This may be most critical in patients with a history of coronary stent placement since our findings suggest that snow shoveling may precipitate subacute stent thrombosis.

Janardhanan, Rajesh; Henry, Zachary; Hur, David J.; Lin, Christine M.; Lopez, David; Reagan, Patrick M.; Rudnick, Sean R.; Koshko, Travis J.; Keeley, Ellen C.

2010-01-01

7

International Plowing Match & Farm Machinery Show  

NSDL National Science Digital Library

The 1995 International Plowing Match & Farm Machinery Show in Ontario, Canada has a site of the Web. The IPM is a non-profit organization of volunteers which annually organizes Canada's largest farm machinery show. The event is commercial and educational. Thousands of school children and educators attend and participate in organized educational activities.

1995-01-01

8

Shovel Operator. Open Pit Mining Job Training Series.  

ERIC Educational Resources Information Center

This training outline for shovel operators, one in a series of eight outlines, is designed primarily for company training foremen or supervisors and for trainers to use as an industry-wide guideline for heavy equipment operator training in open pit mining in British Columbia. Intended as a guide for preparation of lesson plans both for classroom…

Hartley, Larry

9

Simulation of asperity plowing in an atomic force microscope. Part II: Plowing of aluminum alloys  

Microsoft Academic Search

In this second part, we present results of plowing tests on three commercial aluminum alloys using the atomic force microscope technique presented in Part I. Pure (99.99%) aluminum, 5182-O, and 7150-T6 were chosen as substrates because of their different material properties. These properties create different tribological conditions in processes such as rolling, forging, and extrusion where a metal workpiece flows

Steven R. Schmid; Louis G. Hector

1998-01-01

10

Dump truck operator vibration control in high-impact shovel loading operations  

Microsoft Academic Search

The shovel-truck system is used in surface mines due to its flexibility, low-cost operations, maintainability and multi-face operating capability. Technological advances have resulted in large shovels and trucks for bulk, economic operations causing high-impact shovel loading operations (HISLO). The resulting HISLO impact forces cause significant vibrations, which are transmitted through the truck frame into an operator's cabin. Long-term exposure to

Samuel Frimpong; Grzegorz Galecki; Zongyu Chang

2011-01-01

11

(Test and gather data on sweep spike combination tillage tool)  

SciTech Connect

This summary presents the data accumulated to date with only brief comment. It is prepared with the intent that the viewers will offer advice on terminology, data presentation, methods and other. The year end analysis will detail changes in the data due to the tillage treatments. The data is incomplete due to equipment problems and time limitations due to the wet fall and early freeze up. The trial was not completed due to our inability to get the Mikkelsen Chisel Plow Shovel (MCP), a 16 inch sweep with an anhydrous knife, to penetrate untilled land. The MCP shovel penetrated to deep on plowed ground and pulled so hard that the front wheels of our JD4440 tractor were jerked off the ground. The Standard Chisel Plow Shovels (SCP), a 16 inch sweep, worked well and the data is included.

Lukach, J.

1992-06-19

12

[Test and gather data on sweep spike combination tillage tool]. Quarterly technical report, August 1991--March 1992  

SciTech Connect

This summary presents the data accumulated to date with only brief comment. It is prepared with the intent that the viewers will offer advice on terminology, data presentation, methods and other. The year end analysis will detail changes in the data due to the tillage treatments. The data is incomplete due to equipment problems and time limitations due to the wet fall and early freeze up. The trial was not completed due to our inability to get the Mikkelsen Chisel Plow Shovel (MCP), a 16 inch sweep with an anhydrous knife, to penetrate untilled land. The MCP shovel penetrated to deep on plowed ground and pulled so hard that the front wheels of our JD4440 tractor were jerked off the ground. The Standard Chisel Plow Shovels (SCP), a 16 inch sweep, worked well and the data is included.

Lukach, J.

1992-06-19

13

Influence of snow shovel shaft configuration on lumbosacral biomechanics during a load-lifting task.  

PubMed

Lower-back injury from snow shovelling may be related to excessive joint loading. Bent-shaft snow shovels are commonly available for purchase; however, their influence on lower back-joint loading is currently not known. Therefore, the purpose of this study was to compare L5/S1 extension angular impulses between a bent-shaft and a standard straight-shaft snow shovel. Eight healthy subjects participated in this study. Each completed a simulated snow-lifting task in a biomechanics laboratory with each shovel design. A standard motion analysis procedure was used to determine L5/S1 angular impulses during each trial, as well as peak L5/S1 extension moments and peak upper body flexion angle. Paired-samples t-tests (? = 0.05) were used to compare variables between shovel designs. Correlation was used to determine the relationship between peak flexion and peak moments. Results of this study show that the bent-shaft snow shovel reduced L5/S1 extension angular impulses by 16.5% (p = 0.022), decreased peak moments by 11.8% (p = 0.044), and peak flexion by 13.0% (p = 0.002) compared to the straight-shaft shovel. Peak L5/S1 extension moment magnitude was correlated with peak upper body flexion angle (r = 0.70). Based on these results, it is concluded that the bent-shaft snow shovel can likely reduce lower-back joint loading during snow shovelling, and thus may have a role in snow shovelling injury prevention. PMID:23845725

Lewinson, Ryan T; Rouhi, Gholamreza; Robertson, D Gordon E

2014-03-01

14

Old shovels with digital control technology retrofits give new units a run for their money  

SciTech Connect

New digital drive control systems can be retrofitted to shovels and draglines to maximize their performance and keep them running smoothly and reliably. Case histories of successful retrofits are reported. The static drives on a Marion 310 DC drive shovel operating in British Columbia were replaced with Avtron Firing Modules to improve machine availability. Three old Bucyrus 295 M-G set-controlled shovels operated by mines in North Dakota and Labrador which were experiencing excessive downtime were replaced with an Avtron ADD-32DMG field regulator. 2 figs.

Duskey, M.R. [Avtron Manufacturing Inc., Cleveland, OH (United States)

2006-04-15

15

Dynamic plowing nanolithography on polymethylmethacrylate using an atomic force microscope  

Microsoft Academic Search

We present dynamic plowing nanolithography on polymethylmethacrylate films, performed with a scan-linearized atomic force microscope able to scan up to 250 mum with high resolution. Modifications of the surface are obtained by plastically indenting the film surface with a vibrating tip. By changing the oscillation amplitude of the cantilever, i.e., the indentation depth, surfaces can be either imaged or modified.

M. Heyde; K. Rademann; B. Cappella; M. Geuss; H. Sturm; T. Spangenberg; H. Niehus

2001-01-01

16

Test of the Trailed Five-Body Plow with Rotating Moldboards.  

National Technical Information Service (NTIS)

So called combined plows combining a plow body with a rotating rotor are used in a number of foreign countries with the objective of improving the quality of basic soil working and decreasing the draft. For verifying the usefulness of such plows in condit...

I. M. Panov V. A. Shmonin

1967-01-01

17

Evaluation of Urethane and Carbide-Tipped Blades on Wheel-Supported Snow Plows.  

National Technical Information Service (NTIS)

The objective of this study was to evaluate the performance of urethane and carbide-tipped snow plow blades in wheel-supported plows. Their performance was compared to that of VDOT's standard blade arrangement: carbide-tipped blades on plows without wheel...

D. S. Roosevelt B. H. Cottrell

1997-01-01

18

A Common Variation in EDAR Is a Genetic Determinant of Shovel-Shaped Incisors  

PubMed Central

Shovel shape of upper incisors is a common characteristic in Asian and Native American populations but is rare or absent in African and European populations. Like other common dental traits, genetic polymorphisms involved in the tooth shoveling have not yet been clarified. In ectodysplasin A receptor (EDAR), where dysfunctional mutations cause hypohidrotic ectodermal dysplasia, there is a nonsynonymous-derived variant, 1540C (rs3827760), that has a geographic distribution similar to that of the tooth shoveling. This allele has been recently reported to be associated with Asian-specific hair thickness. We aimed to clarify whether EDAR 1540C is also associated with dental morphology. For this purpose, we measured crown diameters and tooth-shoveling grades and analyzed the correlations between the dental traits and EDAR genotypes in two Japanese populations, inhabitants around Tokyo and in Sakishima Islands. The number of EDAR 1540C alleles in an individual was strongly correlated with the tooth-shoveling grade (p = 7.7 × 10?10). The effect of the allele was additive and explained 18.9% of the total variance in the shoveling grade, which corresponds to about one-fourth of the heritability of the trait reported previously. For data reduction of individual-level metric data, we applied a principal-component analysis, which yielded PC1-4, corresponding to four patterns of tooth size; this result implies that multiple factors are involved in dental morphology. The 1540C allele also significantly affected PC1 (p = 4.9 × 10?3), which denotes overall tooth size, and PC2 (p = 2.6 × 10?3), which denotes the ratio of mesiodistal diameter to buccolingual diameter.

Kimura, Ryosuke; Yamaguchi, Tetsutaro; Takeda, Mayako; Kondo, Osamu; Toma, Takashi; Haneji, Kuniaki; Hanihara, Tsunehiko; Matsukusa, Hirotaka; Kawamura, Shoji; Maki, Koutaro; Osawa, Motoki; Ishida, Hajime; Oota, Hiroki

2009-01-01

19

Investigation of select ergonomic interventions for farm youth. Part 1: shovels.  

PubMed

There is some evidence that performing farm chores may place youth at risk of musculoskeletal injuries. However, actual investigations of interventions for farm youth have been sparse. The objective of the current study was to investigate two different types of interventions (add-on handles) for shovels, potentially reducing the risk of injury in farm youth. A lumbar motion monitor was used to capture trunk posture and motion while the youth performed a simulated shoveling task--removal of material from an animal stall. Ratings of perceived exertion and comfort of use were also assessed. The results indicate add-on handles decreased sagittal flexion but increased twisting as compared to regular shovels. Perceived ratings were worse for shovels with add-on handles. Overall, there appears to be a trade-off between sagittal and nonsagittal motion and appears to have minimal impact on risk of low back injury. However, further research is necessary to determine the complete ramifications of this trade-off with respect to the biomechanical load within the low back and on other joints. PMID:19214854

Kotowski, Susan E; Davis, Kermit G; Waters, Thomas R

2009-01-01

20

Petrological, structural and seismic signature of shallow crustal chiseling and crustal splitting: role of paleorift heredity  

NASA Astrophysics Data System (ADS)

Since the concept of crustal flakes was introduced in geology in early seventies the tectonic or lithospheric wedging was recognized in several seismic lines through Alps, Pyrenees, Rocky Mountains and Appalachians. The common factor of all these domains is an existence of rifted lithosphere of different thermal age and their complex seismic pattern is interpreted as a result of single or even double lithospheric wedging. We present 1D and 2D numerical simulations to evaluate the role of cooling time of rifted domain and lithological make-up on the localisation of major detachment zones controlling the depth and thickness of crustal or lithospheric chisels. We show three key configurations of pre-rift and post rift conditions represented by standard crust and hot geotherm (rifted) versus thin crust and mean geotherm (stable), standard crust and mean geotherm (rifted) versus thin crust and mean geotherm (stable), thin crust and hot geotherm (rifted) versus thin crust mean geotherm (stable). We present two geological sections and seismic lines of European Variscides where geochronological, petrological and reliable structural data are available to discuss the geometry of modelled crustal chisels. The role of tectonic heredity, time of cooling and differential strength of cooled rifted domain versus adjacent continent is discussed in terms of exhumation of deep seated rocks and development of ductile structures along strong chisel and adjacent weak zone. Continuous structural and metamorphic history in vertical and lateral directions is explained using the role of transient plastic instabilities during chiselling.

Schulmann, K.; Thompson, A. B.; Stipska, P.; Jezek, J.

2003-04-01

21

Dynamic plowing nanolithography on polymethylmethacrylate using an atomic force microscope  

NASA Astrophysics Data System (ADS)

We present dynamic plowing nanolithography on polymethylmethacrylate films, performed with a scan-linearized atomic force microscope able to scan up to 250 ?m with high resolution. Modifications of the surface are obtained by plastically indenting the film surface with a vibrating tip. By changing the oscillation amplitude of the cantilever, i.e., the indentation depth, surfaces can be either imaged or modified. A program devoted to the control of the scanning process is also presented. The software basically converts the gray scale of pixel images into voltages used to control the dither piezo driving cantilever oscillations. The advantages of our experimental setup and the dependence of lithography efficiency on scanning parameters are discussed. Some insights into the process of surface modifications are presented.

Heyde, M.; Rademann, K.; Cappella, B.; Geuss, M.; Sturm, H.; Spangenberg, T.; Niehus, H.

2001-01-01

22

Comparative Study of Specific Plowing Energy for Mild Steel and Composite Ceramics Using Single Grit Scratch Tests  

Microsoft Academic Search

The present research work compares the specific plowing energy requirement of two different materials: mild steel (ductile material) and composite ceramics (brittle material) using single grit scratch tests. The comparative study of two different materials will enhance the understanding of specific plowing energy. Specific plowing energy depends both on grinding process parameters as well as material property such as hardness.

Vijayender Singh; Sudarsan Ghosh; P. Venkateswara Rao

2011-01-01

23

Energy expenditure and clearing snow: a comparison of shovel and snow pusher  

Microsoft Academic Search

In order to assess the energy demands of manual clearing of snow, nine men did snow clearing work for 15 min with a shovel and a snow pusher. The depth of the snowcover was 400–600 mm representing a very heavy snowfall. Heart rate (HR), oxygen consumption ([Vdot]O2), pulmonary ventilation ( [Vdot]OE), respiratory exchange ratio (R), and rating of perceived exertion (RPE)

JUHANI SMOLANDER; VEIKKO LOUHEVAARA; ESA AHONEN; JUKKA POLARI; TAPIO KLEN

1995-01-01

24

Comparison of Drilling Performance of Chisel and Button Bits on the Electro Hydraulic Driller  

NASA Astrophysics Data System (ADS)

Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the drilling process, the performance of the machine is predicted by selecting an appropriate bit type prior to drilling operations. In this paper, a series of field drilling studies were conducted in order to examine and compare the performance of chisel and button bits including wear on the bits. The effects of taper angle on chisel bits, which are at angles of 105°, 110° and 120°, were investigated in terms of rate of penetration, instantaneous drilling rate and specific energy. The results of drilling and abrasivity tests performed in the laboratory supported the outcome of the field studies. Based on laboratory studies and field observations, it was proven that the conglomerate encountered, though it is very abrasive, is easy to drill. The cutter life in the encountered series is also longer in sandstone formation compared to the conglomerate. Additionally, button bits resulted in lower specific energy and higher penetration rates relative to chisel bits, regardless of their taper angles. The results were also supported with statistical analyses.

Su, Okan; Yarali, Olgay; Akcin, Nuri Ali

2013-11-01

25

Modelling of plowing and shear friction coefficients during high-temperature ball-on-disc tests  

Microsoft Academic Search

During high-temperature ball-on-disc tests of aluminium against steel, hot aluminium deforms and wear track evolves. The individual contributions of plowing and shearing to the apparent friction and the contact pressure are unknown. The aim of the research was to develop a model capable of determining these parameters. It was found that during high-temperature ball-on-disc tests, the plowing friction accounted for

L. Wang; Y. He; J. Zhou; J. Duszczyk

2009-01-01

26

AVERAGE AND INSTANTANEOUS FUEL CONSUMPTION OF IRANIAN CONVENTIONAL TRACTOR WITH MOLDBOARD PLOW IN TILLAGE  

Microsoft Academic Search

John Deere 3140 tractors work powerful and useful in Iran farmlands. In this study two fuel flow meter sensors were used for measuring tractor fuel consumption and the measurement system was installed on diesel engine of a 72.3kW John Deer 3140 tractor. A three-share moldboard plow was used for studying the effect of plow depth variations on tractor fuel consumption.

H. Fathollahzadeh; H. Mobli; A. Rajabipour; S. Minaee; A. Jafari; S. M. H. Tabatabaie

2010-01-01

27

Contact laser transurethral surgery using a sapphire chisel probe firing Nd:YAG  

NASA Astrophysics Data System (ADS)

This is a report on a modified technique for use of a contact laser for transurethral surgery to improve voiding in spinal core injury patients. To produce a channel for voiding, chisel sapphire tips are used to deliver adequate Nd:YAG laser energy to vaporize tissue blocking the urethral passage. We present data on 51 spinal cord injury patients (range 29 - 76 years) who had contact laser surgery in the past 22 months. Urodynamic studies showed detrusor sphincter dyssynergia in 82% of patients. On cystoscopic examination prior to surgery, 39% had associated enlargement of the prostate and/or bladder-neck stenosis. Thirty-one percent also had associated strictures in the bulbous urethra. For transurethral resection of the sphincter, a 12 o'clock incision was made by passing the contact probe repeatedly and/or buttonholing and then cutting the overlying tissue. For vaporization of the prostate and eradication of urethral strictures, the contact chisel probe was passed repeatedly over the surface and also buttonholes were drilled. The overlying tissue was incised with the laser chisel. The buttonhole technique expedited the procedure for creation of an adequate urethral channel for voiding. During surgery, there was minimal blood loss of about 25 - 50 ml per procedure except in 2 patients who lost 100 to 150 ml. All except 4 patients voided satisfactorily within 1 to 8 days (mean 2.7 days) when the catheter was removed following surgery. The initial 4 patients who did not void well are also voiding satisfactorily following repeat surgery.

Perkash, Inder

1995-05-01

28

Preliminary Economics of Mining a Thick Coal Seam by Dragline, Shovel-Truck, and Scraper Mining Systems.  

National Technical Information Service (NTIS)

This Bureau of Mines publication compares the relative economics of three common coal strip-mining techniques. A general overview is presented relating to cost estimation for conventional dragline, shovel-truck, and scraper mining systems. A short-range e...

M. J. Bertoldi

1977-01-01

29

Effects of feedrate and chisel edge on delamination in composites drilling  

NASA Astrophysics Data System (ADS)

Delamination occurring during the drilling of composite laminates has been recognized as a major problem. An analytical model is established to predict critical thrust force and critical feedrate at which the delamination crack begins to propagate. For unidirectional composites, the delamination zone is modeled as an elliptical plate, with clamped edges and subjected to a central load. Based on fracture mechanics, laminated plate theory and cutting mechanics, expressions are developed for critical thrusts and critical feedrates at which delamination is initiated at different ply locations. This model has been verified by experiments. A variable feedrate strategy is formulated based on this model, which avoids delamination while drilling in a time-optimal fashion. In addition, the need to modify tool geometry to avoid delamination is highlighted. Chisel edge width has been identified as an important factor contributing to the thrust force and hence delamination.

Jain, Sanjeev; Yang, Daniel C. H.

30

Chemical characteristics and potential source of fulvic acids leached from the plow layer of paddy soil  

Microsoft Academic Search

To understand better the chemical characteristics and source of dissolved organic matter (DOM) leached from the plow layer of rice paddies, a lysimeter study was conducted, which simulated submerged paddy topsoil during rice growth. The fulvic acid (FA) fraction in the percolation water from the lysimeter was collected by adsorption onto insoluble polyvinylpyrrolidone (PVP), and the temporal variations in its

Nagamitsu Maie; Akira Watanabe; Makoto Kimura

2004-01-01

31

Factors affecting Co2 evolution from the lower plow layer of grassland soil  

Microsoft Academic Search

Microbial activities in the lower plow layer from 11 various fields were compared with those in the uppermost layer. The soils examined were divided into two types: Tenpoku heavy clay soil and Tokachi volcanic ash soil. Soils were taken with stainless steel core samplers and the amounts of in situ CO2 evolution were simulated by incubation test. Amounts of microbial

Shuji Higashida; Akira Nishimune

1988-01-01

32

Nanopattern fabrication by tip plowing technology on 55 nm grating with stitching image method.  

PubMed

An appropriate calibration positioning method is imperative to examine localized tip on nanoscale patterns for scanning probe microscopy (SPM). This paper is to develop a new nanofabrication processes for AFM tip positioning with image stitching method in tip plowing technology. Moreover, this paper adjusts the set-point amplitude (A(sp)) to develop the tip plowing technology for fabricating nanopattern on 55 nm grating gage of a silicon substrate. The developed image stitching program is based on an iterative closet point (ICP) algorithm which has six degrees of freedom alignment. A closed-loop piezo motor is used to tip approach and plow in Z-axis. Experimental result of fabricating nanobagua on 55 nm grating of silicon substrate show that the developed positioning processes with image stitching method verify the feasibility of repeatability for the tip plowing technology successfully. This developed method can be further performed by a commercial atomic force microscope (AFM) with CAD/CAM. This technology can also be applied in dip pen nanolithography (DPN), SPM oxidation lithography and related fabrication technology with AFM tips. PMID:21128433

Chen, Chao-Chang A; Chen, Jr-Rung

2010-07-01

33

Progress report on the Pegasus plow, October--December 1996 and January--March 1997  

SciTech Connect

This is a progress report on a contract related to the invention of a plow which will bury organic waste from farm fields, either in the form of shredded stubble or as whole stalks. The report addresses completion of various tasks in the contract, primarily related to field testing and trying to move the product into the market place.

NONE

1997-04-01

34

[Testing and commercialization of a cotton stalk shredder and plow]. Technical progress report, July--September, 1995  

SciTech Connect

The paper describes plans to field test several prototypes of plows that cut cotton stalks after harvesting and plows then back into the soil to prepare the field for the next planting. Modifications to the design have been made to allow the soil to more easily slide off the plow to reduce fuel consumption. A prototype has been shipped to Australia for testing in their fields and further product development. A farm machinery manufacturer has been selected to build two full-scale preproduction prototypes. Field testing will be done at sites in California and Arizona, since both have regulations specifying that cotton stalks must be shredded.

Thacker, G.W.

1995-10-23

35

Continuous dental replacement in a hyper-chisel tooth digging rodent  

PubMed Central

Contrary to their reptilian ancestors, which had numerous dental generations, mammals are known to usually develop only two generations of teeth. However, a few mammal species have acquired the ability to continuously replace their dentition by the constant addition of supernumerary teeth moving secondarily toward the front of the jaw. The resulting treadmill-like replacement is thus horizontal, and differs completely from the vertical dental succession of other mammals and their extinct relatives. Despite the developmental implications and prospects regarding the origin of supernumerary teeth, this striking innovation remains poorly documented. Here we report another case of continuous dental replacement in an African rodent, Heliophobius argenteocinereus, which combines this dental system with the progressive eruption of high-crowned teeth. The escalator-like mechanism of Heliophobius constitutes an original adaptation to hyper-chisel tooth digging involving high dental wear. Comparisons between Heliophobius and the few mammals that convergently acquired continuous dental replacement reveal that shared inherited traits, including dental mesial drift, delayed eruption, and supernumerary molars, comprise essential prerequisites to setting up this dental mechanism. Interestingly, these dental traits are present to a lesser extent in humans but are absent in mouse, the usual biological model. Consequently, Heliophobius represents a suitable model to investigate the molecular processes leading to the development of supernumerary teeth in mammals, and the accurate description of these processes could be a significant advance for further applications in humans, such as the regeneration of dental tissues.

Gomes Rodrigues, Helder; Marangoni, Pauline; Sumbera, Radim; Tafforeau, Paul; Wendelen, Wim; Viriot, Laurent

2011-01-01

36

Biting performance and skull biomechanics of a chisel tooth digging rodent (Ctenomys tuconax; Caviomorpha; Octodontoidea).  

PubMed

Biting performance is a key factor in vertebrate groups possessing particular food habits. In subterranean rodents that use the incisors as a digging tool, apart from requirements related to gnawing abrasive diets, the force exerted at the incisors tips must be sufficient to break down soils that are often exceedingly compact. The subterranean genus Ctenomys diversified in the southern portion of South America closely associated with the relatively open environments that characterize that region. This genus is considered a "claw and chisel tooth digger," that is, during the excavation of their galleries, the animals break down the soil with both the fore-claws and the incisors. We report here measurements of in vivo bite force in one of the largest species of the genus, C. tuconax, which occupies highland grasslands with compacted soils. We document the combined use of claws and incisors observed under field conditions, also providing measurements of soil compaction in the habitat occupied by this species. We report estimates of bite force at the level of the incisors and cheek teeth calculated from the physiological cross-sectional area of jaw muscles. To this aim, anatomical and biomechanical analyses of the mandibular apparatus were performed in preserved specimens. We found that C. tuconax bites with a higher force than expected for a mammal of its size. To assess anatomical correlates of biting performance, the morphology of the skull and jaw, and incisor second moment of area were compared with those of other caviomorph rodents with different lifestyle. PMID:23203312

Becerra, Federico; Casinos, Adrià; Vassallo, Aldo Iván

2013-02-01

37

Solid Lubrication Fundamentals and Applications. Chapter 5; Abrasion: Plowing and Cutting  

NASA Technical Reports Server (NTRS)

Chapter 5 discusses abrasion, a common wear phenomenon of great economic importance. It has been estimated that 50% of the wear encountered in industry is due to abrasion. Also, it is the mechanism involved in the finishing of many surfaces. Experiments are described to help in understanding the complex abrasion process and in predicting friction and wear behavior in plowing and/or cutting. These experimental modelings and measurements used a single spherical pin (asperity) and a single wedge pin (asperity). Other two-body and three-body abrasion studies used hard abrasive particles.

Miyoshi, Kazuhisa

2001-01-01

38

[Effects of deep plowing and mulch in fallow period on soil water and yield of wheat in dryland].  

PubMed

A field test was carried out in Qiujialing Village, Wenxi, Shanxi from 2009 to 2011 to study the soil water movement of 0-300 cm layer, yield formation and water use efficiency (WUE) of wheat with deep plowing and mulching the whole ground immediately (no mulch as control) 15 days and 45 days after harvest. The results indicated that deep plowing and mulch in fallow period could improve soil water storage of the 100-180 cm layer before sowing, the soil water storage efficiency in fallow period, and soil water storage from pre-wintering stage to booting stage. Compared with deep plowing 15 days after wheat harvest, deep plowing 45 days after wheat harvest did better in improving soil water storage and water use efficiency, as well as ear number and yield, which was more conducive in the year with more precipitation. Generally, deep plowing and mulching after raining during fallow period could benefit the soil water storage and conservation, thus would be helpful to improve wheat yield in dryland. PMID:24765852

Deng, Yan; Gao, Zhi-Qiang; Sun, Min; Zhao, Wei-Feng; Zhao, Hong-Mei; Li, Qing

2014-01-01

39

Lift and drag forces on an inclined plow moving over a granular surface  

NASA Astrophysics Data System (ADS)

We studied the drag and lift forces acting on an inclined plate while it is dragged on the surface of a granular media, both in experiment and in numerical simulation. In particular, we investigated the influence of the horizontal velocity of the plate and its angle of attack. We show that a steady wedge of grains is moved in front of the plow and that the lift and drag forces are proportional to the weight of this wedge. These constants of proportionality vary with the angle of attack but not (or only weakly) on the velocity. We found a universal effective friction law that accounts for the dependence on all the above-mentioned parameters. The stress and velocity fields are calculated from the numerical simulations and show the existence of a shear band under the wedge and that the pressure is nonhydrostatic. The strongest gradients in stress and shear occur at the base of the plow where the dissipation rate is therefore highest.

Percier, Baptiste; Manneville, Sebastien; McElwaine, Jim N.; Morris, Stephen W.; Taberlet, Nicolas

2011-11-01

40

Mechanical-plowing-based high-speed patterning on hard material via advanced-control and ultrasonic probe vibration  

SciTech Connect

In this paper, we present a high-speed direct pattern fabrication on hard materials (e.g., a tungsten-coated quartz substrate) via mechanical plowing. Compared to other probe-based nanolithography techniques based on chemical- and/or physical-reactions (e.g., the Dip-pen technique), mechanical plowing is meritorious for its low cost, ease of process control, and capability of working with a wide variety of materials beyond conductive and/or soft materials. However, direct patterning on hard material faces two daunting challenges. First, the patterning throughput is ultimately hindered by the “writing” (plowing) speed, which, in turn, is limited by the adverse effects that can be excited/induced during high-speed, and/or large-range plowing, including the vibrational dynamics of the actuation system (the piezoelectric actuator, the cantilever, and the mechanical fixture connecting the cantilever to the actuator), the dynamic cross-axis coupling between different axes of motion, and the hysteresis and the drift effects related to the piezoelectric actuators. Secondly, it is very challenging to directly pattern on ultra-hard materials via plowing. Even with a diamond probe, the line depth of the pattern via continuous plowing on ultra-hard materials such as tungsten, is still rather small (<0.5 nm), particularly when the “writing” speed becomes high. To overcome these two challenges, we propose to utilize a novel iterative learning control technique to achieve precision tracking of the desired pattern during high-speed, large-range plowing, and introduce ultrasonic vibration of the probe in the normal (vertical) direction during the plowing process to enable direct patterning on ultra hard materials. The proposed approach was implemented to directly fabricate patterns on a mask with tungsten coating and quartz substrate. The experimental results demonstrated that a large-size pattern of four grooves (20 ?m in length with 300 nm spacing between lines) can be fabricated at a high speed of ?5 mm/s, with the line width and the line depth at ?95 nm and 2 nm, respectively. A fine pattern of the word “NANO” is also fabricated at the speed of ?5 mm/s.

Wang, Zhihua; Zou, Qingze, E-mail: qzzou@rci.rutgers.edu [Mechanical and Aerospace Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854 (United States)] [Mechanical and Aerospace Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854 (United States); Tan, Jun; Jiang, Wei [Electrical and Computer Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854 (United States)] [Electrical and Computer Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854 (United States)

2013-11-15

41

Mechanical-plowing-based high-speed patterning on hard material via advanced-control and ultrasonic probe vibration.  

PubMed

In this paper, we present a high-speed direct pattern fabrication on hard materials (e.g., a tungsten-coated quartz substrate) via mechanical plowing. Compared to other probe-based nanolithography techniques based on chemical- and/or physical-reactions (e.g., the Dip-pen technique), mechanical plowing is meritorious for its low cost, ease of process control, and capability of working with a wide variety of materials beyond conductive and/or soft materials. However, direct patterning on hard material faces two daunting challenges. First, the patterning throughput is ultimately hindered by the "writing" (plowing) speed, which, in turn, is limited by the adverse effects that can be excited/induced during high-speed, and/or large-range plowing, including the vibrational dynamics of the actuation system (the piezoelectric actuator, the cantilever, and the mechanical fixture connecting the cantilever to the actuator), the dynamic cross-axis coupling between different axes of motion, and the hysteresis and the drift effects related to the piezoelectric actuators. Secondly, it is very challenging to directly pattern on ultra-hard materials via plowing. Even with a diamond probe, the line depth of the pattern via continuous plowing on ultra-hard materials such as tungsten, is still rather small (<0.5 nm), particularly when the "writing" speed becomes high. To overcome these two challenges, we propose to utilize a novel iterative learning control technique to achieve precision tracking of the desired pattern during high-speed, large-range plowing, and introduce ultrasonic vibration of the probe in the normal (vertical) direction during the plowing process to enable direct patterning on ultra hard materials. The proposed approach was implemented to directly fabricate patterns on a mask with tungsten coating and quartz substrate. The experimental results demonstrated that a large-size pattern of four grooves (20 ?m in length with 300 nm spacing between lines) can be fabricated at a high speed of ~5 mm/s, with the line width and the line depth at ~95 nm and 2 nm, respectively. A fine pattern of the word "NANO" is also fabricated at the speed of ~5 mm/s. PMID:24289401

Wang, Zhihua; Tan, Jun; Zou, Qingze; Jiang, Wei

2013-11-01

42

Mechanical-plowing-based high-speed patterning on hard material via advanced-control and ultrasonic probe vibration  

NASA Astrophysics Data System (ADS)

In this paper, we present a high-speed direct pattern fabrication on hard materials (e.g., a tungsten-coated quartz substrate) via mechanical plowing. Compared to other probe-based nanolithography techniques based on chemical- and/or physical-reactions (e.g., the Dip-pen technique), mechanical plowing is meritorious for its low cost, ease of process control, and capability of working with a wide variety of materials beyond conductive and/or soft materials. However, direct patterning on hard material faces two daunting challenges. First, the patterning throughput is ultimately hindered by the "writing" (plowing) speed, which, in turn, is limited by the adverse effects that can be excited/induced during high-speed, and/or large-range plowing, including the vibrational dynamics of the actuation system (the piezoelectric actuator, the cantilever, and the mechanical fixture connecting the cantilever to the actuator), the dynamic cross-axis coupling between different axes of motion, and the hysteresis and the drift effects related to the piezoelectric actuators. Secondly, it is very challenging to directly pattern on ultra-hard materials via plowing. Even with a diamond probe, the line depth of the pattern via continuous plowing on ultra-hard materials such as tungsten, is still rather small (<0.5 nm), particularly when the "writing" speed becomes high. To overcome these two challenges, we propose to utilize a novel iterative learning control technique to achieve precision tracking of the desired pattern during high-speed, large-range plowing, and introduce ultrasonic vibration of the probe in the normal (vertical) direction during the plowing process to enable direct patterning on ultra hard materials. The proposed approach was implemented to directly fabricate patterns on a mask with tungsten coating and quartz substrate. The experimental results demonstrated that a large-size pattern of four grooves (20 ?m in length with 300 nm spacing between lines) can be fabricated at a high speed of ˜5 mm/s, with the line width and the line depth at ˜95 nm and 2 nm, respectively. A fine pattern of the word "NANO" is also fabricated at the speed of ˜5 mm/s.

Wang, Zhihua; Tan, Jun; Zou, Qingze; Jiang, Wei

2013-11-01

43

Atomic force microscopy based manipulation of graphene using dynamic plowing lithography  

NASA Astrophysics Data System (ADS)

Tapping mode atomic force microscopy (AFM) is employed for dynamic plowing lithography of exfoliated graphene on silicon dioxide substrates. The shape of the graphene sheet is determined by the movement of the vibrating AFM probe. There are two possibilities for lithography depending on the applied force. At moderate forces, the AFM tip only deforms the graphene and generates local strain of the order of 0.1%. For sufficiently large forces the AFM tip can hook graphene and then pull it, thus cutting the graphene along the direction of the tip motion. Electrical characterization by AFM based electric force microscopy, Kelvin probe force microscopy and conductive AFM allows us to distinguish between the truly separated islands and those still connected to the surrounding graphene.

Vasi?, Borislav; Kratzer, Markus; Matkovi?, Aleksandar; Nevosad, Andreas; Ralevi?, Uroš; Jovanovi?, Djordje; Ganser, Christian; Teichert, Christian; Gaji?, Radoš

2013-01-01

44

Design, development and performance of a disk plow combined with rotary blades  

NASA Astrophysics Data System (ADS)

Disk plow combined with rotary blades, defined as comboplow, is used for soil preparation for planting. The comboplow includes four units: Chassis, concave disk, transmission system and rotary blades. A multiple tillage operation is reduced in a single pass resulting in a potential reduction of soil compaction, labor, fuel cost and saving in time. The comboplow was tested at University Putra Malaysia Research Park, Serdang, Selangor, Malaysia, on three different plots of 675 m2 in the year 2010/2011. The treatments were three types of blade [(straight (S),curved (c) and L-shaped)] and three rotary speeds (130,147and 165 rpm). The parameters were Mean Weight Diameter Dry Basis (MWDd), Mean weight Diameter Wet Basis (MWDW), Aggregate Stability Index (SI) and Instability Index (II).

Hashemi, A.; Ahmad, D.; Othman, J.; Sulaiman, S.

2012-09-01

45

Isotope-Aided Studies in Cereals on the Relative Uptake of Ca, P, and K from Plow Layer and Subsoil.  

National Technical Information Service (NTIS)

By applying inverse isotope dilution, a tracer method was developed to estimate the relative uptake of macronutrients from the plow layer and the subsoil under field conditions. The method was used to determine the cumulative percentage uptake of Ca, P, a...

E. Haak

1977-01-01

46

Fuzzy Boundaries: Color and Gene Flow Patterns among Parapatric Lineages of the Western Shovel-Nosed Snake and Taxonomic Implication  

PubMed Central

Accurate delineation of lineage diversity is increasingly important, as species distributions are becoming more reduced and threatened. During the last century, the subspecies category was often used to denote phenotypic variation within a species range and to provide a framework for understanding lineage differentiation, often considered incipient speciation. While this category has largely fallen into disuse, previously recognized subspecies often serve as important units for conservation policy and management when other information is lacking. In this study, we evaluated phenotypic subspecies hypotheses within shovel-nosed snakes on the basis of genetic data and considered how evolutionary processes such as gene flow influenced possible incongruence between phenotypic and genetic patterns. We used both traditional phylogenetic and Bayesian clustering analyses to infer range-wide genetic structure and spatially explicit analyses to detect possible boundary locations of lineage contact. Multilocus analyses supported three historically isolated groups with low to moderate levels of contemporary gene exchange. Genetic data did not support phenotypic subspecies as exclusive groups, and we detected patterns of discordance in areas where three subspecies are presumed to be in contact. Based on genetic and phenotypic evidence, we suggested that species-level diversity is underestimated in this group and we proposed that two species be recognized, Chionactis occipitalis and C. annulata. In addition, we recommend retention of two subspecific designations within C. annulata (C. a. annulata and C. a. klauberi) that reflect regional shifts in both genetic and phenotypic variation within the species. Our results highlight the difficultly in validating taxonomic boundaries within lineages that are evolving under a time-dependent, continuous process.

Wood, Dustin A.; Fisher, Robert N.; Vandergast, Amy G.

2014-01-01

47

An assessment of heavy metal bioaccumulation in Asian swamp eel, Monopterus albus, during plowing stages of a paddy cycle.  

PubMed

Livers and muscles of swamp eels (Monopterus albus) were analyzed for bioaccumulation of heavy metals during the plowing stage of a paddy cycle. Results showed heavy metals were bioaccumulated more highly in liver than muscle. Zinc (Zn) was the highest bioaccumulated metal in liver (98.5 ± 8.95 ?g/g) and in muscle (48.8 ± 7.17 ?g/g). The lowest bioaccumulated metals were cadmium (Cd) in liver (3.44 ± 2.42 ?g/g) and copper (Cu) in muscle (0.65 ± 0.20 ?g/g). In sediments, Zn was present at the highest mean concentration (52.7 ± 2.85 ?g/g), while Cd had the lowest mean concentration (1.04 ± 0.24 ?g/g). The biota-sediment accumulation factor (BSAF) for Cu, Zn, Cd and nickel (Ni) in liver tissue was greater than the corresponding BSAF for muscle tissue. For the three plowing stages, metal concentrations were significantly correlated between liver and muscle tissues in all cases, and between sediment and either liver or muscle in most cases. Mean measured metal concentrations in muscle tissue were below the maximum permissible limits established by Malaysian and U.S. governmental agencies, and were therefore regarded as safe for human consumption. PMID:23666324

Sow, Ai Yin; Ismail, Ahmad; Zulkifli, Syaizwan Zahmir

2013-07-01

48

DIVISION S-6—SOIL & WATER MANAGEMENT & CONSERVATION Tillage and Crop Influences on Physical Properties for an Epiaqualf  

Microsoft Academic Search

tillage usually has been found to increase b compared with moldboard and chisel plow (Kitur et al., 1993; Lal, Tillage impacts on soil properties differ among soils. This study 1999). Bulk density usually is lowest immediately after investigated tillage, cropping, and wheel traffic (WT) effects of 13-yr of no-tillage (NT), chisel plow (CP), and moldboard plow (MP) under tillage and

Humberto Blanco-Canqui; C. J. Gantzer; S. H. Anderson; E. E. Alberts

49

Comparison of impacts on macroinvertebrates and fish from gas pipeline installation by wet-ditching and plowing  

SciTech Connect

Biotic effects from wet-ditching were investigated at the Little Miami River, Ohio. Invertebrate densities decreased at, and a short distance below, the crossing site; partial benthic recolonization occurred within three weeks of construction, while complete recolonization occurred within seven months. Fish recolonized the affected area within one month, but densities were reduced; within eight months after construction, the fish community was similar to that observed before construction. Biotic effects from the plow method were examined at Canada Creek, Michigan. No significant impacts on benthic macroinvertebrates were detected. During ramp excavation, increased macroinvertebrate drift densities were noted, as well as increased occurrence of terrestrial invertebrates in the drift; upon completion of ramp excavation, drift composition approximated that before construction. No effects on fish species were indicated. Overall, no biotic impacts were detected within three days after pipeline installation. 23 refs., 4 figs., 3 tabs.

Vinikour, W.S.; Schubert, J.P.; Gartman, D.K.

1987-01-01

50

Direct Measurement of Plowing Friction and Wear of a Polymer Thin Fill Using the Atomic Force Microscope, Reprinted from the Journal of Materials Research, Vol. 16, 1487-1492, 2001.  

National Technical Information Service (NTIS)

Nanometer-scale plowing friction and wear of a polycarbonate thin film were directly measured using an atomic force microscope (AFM) with nanoscratching capabilities. During the nanoscratch tests, lateral forces caused discrepancies between the maximum fo...

B. Du M. R. VanLandingham Q. Zhang T. He

2000-01-01

51

Plow and ridge nanofabrication.  

PubMed

Traditionally, scanning probe lithography tools are limited in resolution by the radius of curvature of the tip used. Herein, an approach is described for patterning the ridge of piled-up polymer that naturally occurs when a scanning probe is pressed against a soft surface. The use of this phenomenon to transfer patterns to hard materials with 20 nm resolution is demonstrated. PMID:23427089

Shim, Wooyoung; Brown, Keith A; Zhou, Xiaozhu; Rasin, Boris; Liao, Xing; Schmucker, Abrin L; Mirkin, Chad A

2013-09-23

52

Effect of Soil Plowing and Fertilization on the Susceptibility of Four Olive Cultivars to the Insect Bactrocera oleae and the Fungi Sphaeropsis dalmatica and Spilocaea oleagina  

Microsoft Academic Search

Susceptibility to the insectBactrocera oleae and the fungiSpilocaea oleagina andSphaeropsis dalmatica was investigated in four olive cultivars, two for table fruit production (Kalamon and Chondrolia Chalkidikis) and two for\\u000a oil production (Lianolia and Koroneiki). Cv. Chondrolia Chalkidikis was the most susceptible to all three pathogens, followed\\u000a by cv. Kalamon. Soil plowing and the organic fertilizer Bio-Trust® (10-3-6+8% MgCO3+10% CaCO8) increased

E. Navrozidis; Z. Zartaloudis; T. Thomidis; N. Karagiannidis; K. Roubos; Z. Michailides

2007-01-01

53

The formation of the agrogenic typical chernozem profile in the Ukrainian forest-steppe after plowing virgin steppe and fallow soils  

NASA Astrophysics Data System (ADS)

The data on the changes in the physicochemical, biological, and agrochemical properties of a loamy-clayey typical chernozem after plowing a 40-year-old Fallow (for six cycles of a cereal-beet rotation) and a sandy-loamy typical chernozem (for eighteen cycles of a five-course rotation) under different intensities of their use are presented. The major role of the mineral and organic fertilizers and the methods of their application have been revealed in the formation of the humus profile, the acid-base characteristics, and the agrophysical and agrochemical properties.

Nosko, B. S.

2013-03-01

54

TOMATO YIELD AND SOIL QUALITY AS INFLUENCED BY TILLAGE, COVER CROPPING, AND NITROGEN FERTILIZATION  

Microsoft Academic Search

Tomato yield and soil quality may be influenced by management practices and climatic conditions. We examined the effects of tillage (no-till, chisel plowing, and moldboard plowing), cover crop (hairy vetch (Vicia villosa Roth) and no hairy vetch), and N fertilization (0, 80, and 160 lb N acre-1) on tomato yield and N uptake, root growth, and soil C and N

Upendra M. Sainju; Bharat P. Singh; Sidat Yaffa

55

Site Tamper and Material Plow Tool - STAMP  

NASA Technical Reports Server (NTRS)

A non-actuated tool has been developed for preparing regolith for in situ measurement by smoothing uneven surfaces and excavating fresher subsurface material for planetary exploration. The STAMP tool contains two tools to prepare regolith for in situ measurement: a tamper to smooth uneven surfaces, and a blade to excavate fresher subsurface material.

Aisen, Norman M.; Collins, Curtis L.; Trebi-Ollennu, Ashitey

2012-01-01

56

Freedom's Plow: Teaching in the Multicultural Classroom.  

ERIC Educational Resources Information Center

Teachers are the central players in building a multiracial and multicultural democracy, and the schools where teachers work are one of the primary institutions where a new society is born. The 17 chapters in this volume provide resources for people seeking to build fully democratic schools and to make the schools agents of democracy in an…

Perry, Theresa, Ed.; Fraser, James W.

57

Anticipating Stimulus Money for Campus Projects, Colleges Get "Shovel Ready"  

ERIC Educational Resources Information Center

Help for colleges may be on the way in the $825-billion stimulus package being pressed by Congressional leaders. The bill that House Democrats introduced this month includes $7-billion for higher-education modernization, renovation, and repair that could kick-start projects like upgrading heating and cooling systems, fixing roofs, and doing…

Carlson, Scott

2009-01-01

58

Shoveling Up: The Impact of Substance Abuse on State Budgets.  

ERIC Educational Resources Information Center

This report presents findings of a 3-year analysis conducted on the impact of substance abuse on state budgets. An advisory panel of public officials, researchers, and financial experts was convened to provide guidance. They conducted an extensive review of articles and publications linking substance abuse to public spending. Several studies were…

Columbia Univ., New York, NY. National Center on Addiction and Substance Abuse.

59

Improving Visibility for Snow Plow Operators. Executive Summary.  

National Technical Information Service (NTIS)

Safe snowplow operation is a demanding job, requiring a keen awareness of conditions and location. Poor visibility due to windshield icing is a serious safety factor. The standard windshield defrosting systems are often inadequate to handle the volume of ...

P. Orth

1997-01-01

60

Nitrous Oxide Emissions from Corn–Soybean Systems in the Midwest  

Microsoft Academic Search

Soil N2O emissions from three corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) systems in central Iowa were measured from the spring of 2003 through February 2005. The three manage- ments systems evaluated were full-width tillage (fall chisel plow, spring disk), no-till, and no-till with a rye (Secale cereale L. 'Rymin') winter cover crop. Four replicate plots of each treatment

Timothy B. Parkin; Thomas C. Kaspar

2006-01-01

61

Computer simulation of drill-rig\\/shovel operations in open-pit mines  

Microsoft Academic Search

In open-pit mining, there are four main operations: drilling, blasting, loading, and haulage. In the past years, several studies have been made on the shoval-truck systems. However, the drilling-blasting-loading system was neglected in spite of the fact that it takes 30--40% of the total expenditure in production. In order to cover this gap, a computer simulation program was developed and

Yun Qing-xia

1982-01-01

62

Reducing adhesion of soil against loading shovel using bionic electro-osmosis method  

Microsoft Academic Search

Bionic electro-osmosis, a new method of reducing soil adhesion to soil-engaging components or parts of terrain machines, is presented. It is based on the anti-adhesion mechanism of the body surfaces of soil burrowing animals. The key feature of bionic electro-osmosis is to arrange a series of electric pole plates to create a non-smooth working surface. The static and dynamic effects

Luquan Ren; Qian Cong; Jin Tong; Bingcong Chen

2001-01-01

63

"Shovel-ready" Sequences as a Stimulus for the Next Generation of Life Scientists  

PubMed Central

Genomics and bioinformatics are dynamic fields well-suited for capturing the imagination of undergraduates in both research laboratories and classrooms. Currently, raw nucleotide sequence is being provided, as part of several genomics research initiatives, for undergraduate research and teaching. These initiatives could be easily extended and much more effective if the source of the sequenced material and the subsequent focus of the data analysis were aligned with the research interests of individual faculty at undergraduate institutions. By judicious use of surplus capacity in existing nucleotide sequencing cores, raw sequence data could be generated to support ongoing research efforts involving undergraduates. This would allow these students to participate actively in discovery research, with a goal of making novel contributions to their field through original research while nurturing the next generation of talented research scientists.

Boyle, Michael D.

2010-01-01

64

Teach Students to Dig for Understanding Using an Unexpected Technological Shovel  

ERIC Educational Resources Information Center

Online genealogy tools is an unexpected resource as these tools not only serve valuable for genealogy research, but also can be used by students to learn about their country's past and learn to use primary materials to draw conclusions. Some of these Online sources like the 1880 census available at www.ancestry.com, www.thepastwhispers.com, which…

Lake, Susan E. L.

2004-01-01

65

About Problems of Nonlinear Dynamics of the Elastic Rod Elements in Practice of Chisel Works  

NASA Astrophysics Data System (ADS)

The purpose of the paper is modeling of nonlinear vibrations and stability of movement of boring columns at various complicating factors taking into account finite deformations in particular. Movement of boring columns for shallow drilling (up to 500 m) applied in oil-gas extractive industry is considered. Various types of loading and deformations of rod elements are developed in the paper. Nonlinear models of movement of a compressed-torsion drill rod within the nonlinear theory of finite deformations of V.V. Novozhilov are constructed. A method for its analysis and criterion of dynamic stability are offered. The case of a flat curve of a rotating drill rod under the action of variable longitudinal force is investigated at an assumption of finiteness of elastic deformations. The numerical analysis of its elastic dislocations and instability zones of the basic resonance is carried out, which confirm the efficiency of the offered nonlinear dynamic model of rod elements and techniques for their calculation.

Khajiyeva, L.

66

Competition for IL-2 between Regulatory and Effector T Cells to Chisel Immune Responses  

PubMed Central

In this review we discuss how the competition for cytokines between different cells of the immune system can shape the system wide immune response. We focus on interleukin-2 (IL-2) secretion by activated effector T cells (Teff) and on the competition for IL-2 consumption between Teff and regulatory T cells (Treg). We discuss the evidence for the mechanism in which the depletion of IL-2 by Treg cells would be sufficient to suppress an autoimmune response, yet not strong enough to prevent an immune response. We present quantitative estimations and summarize our modeling effort to show that the tug-of-war between Treg and Teff cells for IL-2 molecules can be won by Treg cells in the case of weak activation of Teff leading to the suppression of the immune response. Or, for strongly activated Teff cells, it can be won by Teff cells bringing about the activation of the whole adaptive immune system. Finally, we discuss some recent applications attempting to achieve clinical effects through the modulation of IL-2 consumption by Treg compartment.

Hofer, Thomas; Krichevsky, Oleg; Altan-Bonnet, Gregoire

2012-01-01

67

Effect of tillage system and cumulative rainfall on multifractal parameters of soil surface microrelief  

NASA Astrophysics Data System (ADS)

Mathematical description of the spatial characteristics of soil surface microrelief still remains a challenge. Soil surface roughness parameters are required for modelling overland flow and erosion. The objective of this work was to evaluate the potential of multifractal for analyzing the decay of initial surface roughness induced by natural rainfall under different soil tillage systems. Field experiments were performed on an Oxisol at Campinas, São Paulo State (Brazil). Six tillage treatments, namely, disc harrow, disc plow, chisel plow, disc harrow + disc level, disc plow + disc level and chisel plow + disc level were tested. In each plot soil surface microrelief was measured for times, with increasing amounts of natural rainfall using a pinmeter. The sampling scheme was a square grid with 25 x 25 mm point spacing and the plot size was 1350 x 1350 mm, so that each data set consisted of 3025 individual elevation points. Duplicated measurements were taken per treatment and date, yielding a total of 48 experimental data sets. All the investigated microrelief data sets exhibited, in general, scale properties, and the degree of multifractality showed wide differences between them. Multifractal analysis distinguishes two different patterns of soil surface microrelief, the first one has features close to monofractal spectra and the second clearly indicates multifractal behavior. Both, singularity spectra and generalized dimension spectra allow differentiating between soil tillage systems. In general, changes in values of multifractal parameters under simulated rainfall showed no or little correspondence with the evolution of the vertical microrelief component described by indices such as the standard deviation of the point height measurements. Multifractal parameters provided valuable information for chararacterizing the spatial features of soil surface microrelief as they were able to discriminate data sets with similar values for the vertical component of roughness.

Vidal Vázquez, E.; Miranda, J. G. V.; Mirás-Avalos, J. M.; Díaz, M. C.; Paz-Ferreiro, J.

2009-04-01

68

X-ray computed microtomography analysis of the influence of different agricultural treatments on the topsoil porosity of a Grey Brown Luvisol from Ontario  

NASA Astrophysics Data System (ADS)

One of the most important applications of X-ray computed tomography (CT) for the study of soil is the characterization of the shape and spatial distribution of pores. Analysis of 3D X-ray CT image data, related to different pore categories, can provide insight to soil structural changes, which have implications in water infiltration and soil aeration, resulting from agricultural practices. The aim of this study was to evaluate changes in the spatial characteristics of voids, due to tillage practices, in the Ap horizon of an Orthic Grey- Brown Luvisol (located at the Elora Research Station of the University of Guelph). Undisturbed oriented soil samples were collected from ten plots representing different tillage treatments: spring moldboard plow, spring moldboard plow, cultivate and pack, fall moldboard plow, cultivate and pack, spring tandem disc, no cultivator, fall offset disc, fall offset disc, cultivate and pack, fall chisel plow, cultivate and pack, zero zone till (soys twin rows), zero tillage (long term), and zero tillage (corn residue removed in row, soys twin rows). Since the utilization of standardized classes, in the quantification of similar features, proved to be necessary in order to obtain comparable results, categories of pores, separated according to their size, circularity and orientation were considered in the interpretation of data. Total volume of pores and volume percentage of each class were calculated, revealing substantial differences among the analyzed soil samples.

Taina, I. A.; Heck, R. J.; Scaiff, N. T.

2009-05-01

69

Force and flow at the onset of drag in plowed granular media.  

PubMed

We study the transient drag force FD on a localized intruder in a granular medium composed of spherical glass particles. A flat plate is translated horizontally from rest through the granular medium to observe how FD varies as a function of the medium's initial volume fraction, ?. The force response of the granular material differs above and below the granular critical state, ?c, the volume fraction which corresponds to the onset of grain dilatancy. For ??c, FD rapidly rises to a maximum and then decreases over further displacement. The maximum force for ?>?c increases with increasing drag velocity. In quasi-two-dimensional drag experiments, we use granular particle image velocimetry (PIV) to measure time resolved strain fields associated with the horizontal motion of a plate started from rest. PIV experiments show that the maxima in FD for ?>?c are associated with maxima in the spatially averaged shear strain field. For ?>?c the shear strain occurs in a narrow region in front of the plate, a shear band. For ??c, surface particles move only during the formation of the shear band, coincident with the maxima in FD, after which the particles remain immobile until the sheared region reaches the measurement region. PMID:24827236

Gravish, Nick; Umbanhowar, Paul B; Goldman, Daniel I

2014-04-01

70

Evaluation of surgically assisted rapid maxillary expansion with piezosurgery versus oscillating saw and chisel osteotomy - a randomized prospective trial  

PubMed Central

Background Ultrasonic bone-cutting surgery has been introduced as a feasible alternative to the conventional sharp instruments used in craniomaxillofacial surgery because of its precision and safety. The piezosurgery medical device allows the efficient cutting of mineralized tissues with minimal trauma to soft tissues. Piezoelectric osteotome has found its role in surgically assisted rapid maxillary expansion (SARME), a procedure well established to correct transverse maxillary discrepancies. The advantages include minimal risk to critical anatomic structures. The purpose of this clinical comparative study (CIS 2007-237-M) was to present the advantages of the piezoelectric cut as a minimally invasive device in surgically assisted, rapid maxillary expansion by protecting the maxillary sinus mucosal lining. Methods Thirty patients (18 females and 12 males) at the age of 18 to 54 underwent a surgically assisted palatal expansion of the maxilla with a combined orthodontic and surgical approach. The patients were randomly divided into two separate treatment groups. While Group 1 received conventional surgery using an oscillating saw, Group 2 was treated with piezosurgery. The following parameters were examined: blood pressure, blood values, required medication, bleeding level in the maxillary sinus, duration of inpatient stay, duration of surgery and height of body temperature. Results The results displayed no statistically significant differences between the two groups regarding laboratory blood values and inpatient stay. The duration of surgery revealed a significant discrepancy. Deploying piezosurgery took the surgeon an average of 10 minutes longer than working with a conventional-saw technique. However, the observation of the bleeding level in the paranasal sinus presented a major and statistically significant advantage of piezosurgery: on average the bleeding level was one category above the one of the remaining patients. Conclusion This method of piezoelectric surgery with all its advantages is going to replace many conventional operating procedures in oral and maxillofacial surgery. Trial registration CIS 2007-237-M

2013-01-01

71

Nitrous oxide emissions from corn-soybean systems in the midwest.  

PubMed

Soil N2O emissions from three corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems in central Iowa were measured from the spring of 2003 through February 2005. The three managements systems evaluated were full-width tillage (fall chisel plow, spring disk), no-till, and no-till with a rye (Secale cereale L. 'Rymin') winter cover crop. Four replicate plots of each treatment were established within each crop of the rotation and both crops were present in each of the two growing seasons. Nitrous oxide fluxes were measured weekly during the periods of April through October, biweekly during March and November, and monthly in December, January, and February. Two polyvinyl chloride rings (30-cm diameter) were installed in each plot (in and between plant rows) and were used to support soil chambers during the gas flux measurements. Flux measurements were performed by placing vented chambers on the rings and collecting gas samples 0, 15, 30, and 45 min following chamber deployment. Nitrous oxide fluxes were computed from the change in N2O concentration with time, after accounting for diffusional constraints. We observed no significant tillage or cover crop effects on N2O flux in either year. In 2003 mean N2O fluxes were 2.7, 2.2, and 2.3 kg N2O-N ha(-1) yr(-1) from the soybean plots under chisel plow, no-till, and no-till + cover crop, respectively. Emissions from the chisel plow, no-till, and no-till + cover crop plots planted to corn averaged 10.2, 7.9, and 7.6 kg N2O-N ha(-1) yr(-1), respectively. In 2004 fluxes from both crops were higher than in 2003, but fluxes did not differ among the management systems. Fluxes from the corn plots were significantly higher than from the soybean plots in both years. Comparison of our results with estimates calculated using the Intergovernmental Panel on Climate Change default emission factor of 0.0125 indicate that the estimated fluxes underestimate measured emissions by a factor of 3 at our sites. PMID:16825470

Parkin, Timothy B; Kaspar, Thomas C

2006-01-01

72

Plowing in Rocky Land: Organizational Culture, Managed Change, and Quality Improvement in Selected Romanian Post-Communist Libraries  

Microsoft Academic Search

Romanian libraries have had a rich heritage of collecting and preserving materials in the domains of national and foreign history, literature, art, and science. During the communist regime they served as propaganda tools for the government's Marxist ideology. In post-communist Romania, there is a desire among some librarians to promote change from a system of limited access to information to

IRENE OWENS; HERMINA G. B. ANGHELESCU

1999-01-01

73

[Testing and commercialization of a cotton stalk shredder and plow]. Technical progress report, October--December 1995  

SciTech Connect

This quarterly report describes work on Task 1: Field test and sell prototype to Ellis Equipment, Ltd; Task 2: Design, build, and field test two prototypes; and Task 3: Produce and sell Pegasus to farmers. The equipment has been built to shred stalks, deeply till the soil, and prepare seedbeds for cotton plants. The equipment has been field tested in Australia and is currently being field tested in California and Arizona. Unexpected problems appeared with hard dry soils and this report describes improvements made.

Thacker, G.W.

1996-01-27

74

Dissolved organic C and N pools in soils amended with composted and thermally-dried sludge as affected by soil tillage systems and sampling depth  

NASA Astrophysics Data System (ADS)

Soil tillage practices exert a significant influence on the dynamic of soluble organic C and N pools, affecting nutrient cycling in agricultural systems by enhancing its mineralization through microbial activities or stabilization in soil microaggregates, which contribute to mitigate greenhouse gases emissions. The objective of the present research was to determine the influence of three different soil management systems (moldboard plowing, chisel and no-tillage) and the application of composted sludge (CS) and thermally-dried sewage sludge (TSS) obtained from wastewater treatment processes on dissolved organic C (water-soluble organic C -WSOC-, carbohydrates, phenolic compounds) and soluble N (total-N, NH4+, NO3-) pools in a long-term field experiment (27 years) conducted on a sandy-loam soil at the experimental station "La Higueruela" (40° 03'N, 4° 24'W) under semi-arid conditions. Both organic amendments were applied at a rate of 30 tonnes per hectare prior to tillage practices. Unamended soils were used as control for each tillage system. Soil sampling was performed two months after tillage practices at the following depths for each treatment: 0-10 cm, 10-20 cm and 20-30 cm. Results obtained for unamended soils showed that no-tillage management increased total-N, NH4+ and NO3- contents at the 0-10 cm depth samples, meanwhile WSC and carbohydrates contents were larger at 20-30 cm depth samples in both moldboard and no-tillage plots. CS and TSS-amended soils presented a general increase in soluble C and N compounds, being significantly higher in TSS-amended soils, as TSS contains a great amount of labile organic C and N substrates due to the lack of stabilization treatment. TSS-amended soils under no-tillage and chisel plowing showed larger N, NH4+ and NO3- content at the 0-10 cm samples, meanwhile moldboard management exhibited larger NH4+ and NO3- content at 10-20 and 20-30 cm samples, possibly due to the incorporation of TSS at deeper depths (20-40 cm). CS and TSS-amended soils in no-tillage system showed the largest content of organic C pools at 0-10 cm depth samples due to less soil disturbance and the input of organic substrates with CS and TSS on soil surface. CS and TSS-amended soils under chisel plowing exhibited similar contents of soluble organic C pools at 10-20 and 20-30 cm depth samples and only TSS-amended soils increased significantly WSOC content at 0-10 cm samples. Similarly, contents of WSOC and carbohydrates in moldboard plowing were distributed more uniformly throughout the soil profile due to the turnover of soil and CS and TSS amendments into the plow layer. Acknowledgements: this research was supported by the Spanish CICYT, Project no. CTM2011-25557.

García-Gil, Juan Carlos; Soler-Rovira, Pedro Angel; García López de Sa, Esther; Polo, Alfredo

2013-04-01

75

Management impacts and remote sensing applications for water quality assessment  

NASA Astrophysics Data System (ADS)

This research, consisting of three parts, was designed to improve understanding of non-point pollution sources in the Minnesota River Basin and how adoption of conservation tillage practice (chisel plow with about 30% residue cover) might affect non-point source pollution and crop yield from relatively flat lands in the Minnesota River Basin. The first part was a plot experiment at Lamberton, MN that tested the water quality impacts of two tillage (moldboard vs. chisel) systems, and two nutrient source (liquid hog manure vs. urea) treatments. Four years of natural surface runoff and tile drainage showed few significant differences in water quality parameters from these relatively flat plots. Annual average sediment loss from the plots was 1260 kg/ha with 1.4 kg/ha and 0.13 kg/ha associated total and dissolved P loss respectively. Annual average NO3-N losses through tile drainage were 9.1 kg/ha. Average annual corn grain yield was reduced by 0.4 Mg/ha in the four-year average yield under the chisel system. The second project investigated remote sensing and the Tillage Transect Survey (TTS) accuracy for measuring crop residue cover. When residues were grouped into 5 cover categories the TTS accuracy (49%) outperformed all models (best model = 39%), but models performed as good or better (up to 80%) than the TTS when only two cover categories were used. The third project used airborne scanning laser altimetry to determine mass wasting of bank materials from the Blue Earth River. For the time between the April 2000 and April 2001 scans, between 23 and 56% of the sediment transported by the river had its source from bank collapse and erosion. For the same period, total P contribution from riverbank erosion was 201 t.

Thoma, David Patrick

76

How to get in and out of the skull: from tumi to "hammer and chisel" to the Gigli saw and the osteoplastic flap.  

PubMed

Making "holes in the skull" is an ancient art and by some is considered the second oldest profession in the world-the first being prostitution. Early surgeons, and later on neurosurgeons, devised a number of ingenious ways to make a hole in the skull or elevate a depressed skull fracture. Trephined skulls from antiquity have now been found in most parts of world, showing that the art of trephining is not only ancient but clearly widespread. Beginning with antiquity the author traces the development of this surgical skill by reviewing the various tools used and surgical designs to perform what is now called a craniotomy. PMID:24708162

Goodrich, James Tait

2014-04-01

77

Area terrace pit coal mining systems: volume 1technical and economic evaluation of terrace pit mining systems. Open file report (final) Sep 1977Jul 1980  

Microsoft Academic Search

This report is principally concerned with the engineering and economic feasibility of area surface coal mining systems other than draglines. This analysis evaluates shovel-trucks, shovel-crusher-conveyors, and shovel-rail excavation and haulage systems for an assortment of geologic environments and production rates in the Powder River Basin (PRB). Shovel-trucks, front-end loader-trucks, and shovel-crusher conveyors were studied in a multiseam, dipping geologic area

F. Leonard; C. Simon; M. Stoddard; M. Verma; M. White

1980-01-01

78

Area terrace pit coal mining systems: volume 2appendices. Open file report (final) Sep 1977Jul 1980  

Microsoft Academic Search

This report is principally concerned with the engineering and economic feasibility of area surface coal mining systems other than draglines. This analysis evaluates shovel-trucks, shovel-crusher-conveyors, and shovel-rail excavation and haulage systems for an assortment of geologic environments and production rates in the Powder River Basin (PRB). Shovel-trucks, front-end loader-trucks, and shovel-crusher-conveyors were studied in a multiseam, dipping geologic area of

F. Leonard; C. Simon; M. Stoddard; M. Verma; M. White

1980-01-01

79

Salmonella and fecal indicator bacteria in tile waters draining poultry litter application fields in central Iowa  

NASA Astrophysics Data System (ADS)

E. coli and enterococci are commonly used as pathogen indicators in surface waters. Along with these indicators, pathogenic Salmonella are prevalent in poultry litter, and have the potential to be transported from land-application areas to tile waters and ultimately to impact waters that are used for drinking-water and recreation. The fate and transport of these bacteria to drainage tiles from application fields, and the correlation of fecal indicator bacteria to pathogens in this setting, is poorly understood. In this field study, samples were obtained from poultry litter, soil, and drainage tile waters below chisel-plowed and no-till cornfields in central Iowa where poultry litter was applied each year in late spring prior to planting. Litter was applied at three different rates; commercial fertilizer with no litter, a low application rate based on the nitrogen requirements of the corn (PL1), and double the low rate (PL2). This site is characterized by low sloping (0-9%) Clarion and Nicollet soils, which are derived from glacial till. Samples were collected from April to September for three years (2010-12) when tiles were flowing. Record high precipitation fell during the sampling period in 2010, while 2011 and 2012 were exceptionally dry years at this location. Grab samples were taken directly from flowing tiles after every rainfall event (>2 cm in less than 24 hours) and samples were collected hourly throughout selected events using an automatic sampling device. Concentrations of E. coli, enterococci and Salmonella spp. were quantified by membrane filtration and growth on selective agars. Peak bacteria concentrations following rainfall events were often one order of magnitude higher in tile waters discharging from no-till plots, despite the smaller size and lower tile flow rates at these plots compared to the chisel-plowed plots. Bacteria concentrations regularly varied by two orders of magnitude in response to rainfall events. Bacteria transport via macropores was indicated by a rise in concentrations during or shortly after rainfall, but prior to any increase in tile flow. Macropores located above the tile lines were observed during smoke tests in 2012 confirming significantly greater macropore densities above tile lines in the no-till plots (average 23.2 macropores/m^2) as compared to the chisel-plowed plots (average 1.6 macropores/m^2). Identifiable macropores were generally within a 0.4m-wide zone above the tile lines. While bacterial loading to tile lines was dominated by rainfall-driven events, transport of bacteria to tile lines was observed less than a day after application under unsaturated conditions in 2012. Indicator bacteria concentrations were poorly correlated to Salmonella spp. throughout the study period, with water sample concentrations as high as 4x10^3 cfu/100 ml Salmonella spp. in samples where no E. coli or enterococci were detected. The differences in precipitation from year-to-year had the greatest effect on E. coli concentrations which averaged between 331 - 2140 cfu/100ml under the PL1 and PL2 treatments in 2010, and rarely exceeded 10 cfu/100ml in the month after litter application during dry years. Enterococci were similarly affected, while dry conditions did not result in lower average Salmonella spp. counts.

Hruby, C.; Soupir, M.

2012-12-01

80

Strength Properties and Organic Carbon of Soils in the North Apalachian Region  

SciTech Connect

Soil strength influenced by management and soil properties controls plant growth, root development, and soil-moisture relations. The impact of textural and structural parameters on soil strength is moderated by soil organic C (SOC) concentration. Therefore, the objectives of this study were to assess differences in soil strength and SOC concentration in watersheds under long-term (>15 yr) management practices in the North Appalachian region on a predominantly Typic Hapludults on undulating slopes (>6% slope). Seven watersheds without field replication under moldboard plow (MP), chisel plow, disk with beef cattle manure (DiskM), no-till with beef cattle manure (NTm), no-till with no beef cattle manure (NTnm), pasture, and forest were studied. Cone index (CI), shear strength, bulk density (b), volumetric moisture content (v), and SOC concentration were determined at the summit, backslope, and footslope landscape positions at the 0- to 10-, 10- to 20-, and 20- to 30-cm depths. The SOC concentration was slightly higher at the footslope than at the summit position in the cultivated watersheds. The b was lower at the footslope than at the summit in NTm (1.22 vs. 1.42 Mg m{sup -3}) and chisel (1.34 vs. 1.47 Mg m{sup -3}) treatments. Forest had the lowest CI (0.19 MPa), shear strength (6.11 kPa), and b (0.93 Mg m{sup -3}) and the highest SOC concentration (62.7 g kg{sup -1}), whereas MP had the highest CI (0.67 MPa), shear strength (25.5 kPa), b (1.44 Mg m{sup -3}), and the lowest SOC concentration (13.6 g kg{sup -1}) in the 0- to 10-cm depth (P < 0.01). The SOC concentration in NTm was 1.7 times higher than that in NTnm, and both no-till treatments had lower b (<1.21 Mg m{sup -3}) than MP (1.44 Mg m{sup -3}) at 0- to 10-cm depth (P < 0.01). Manuring decreased both CI and shear strength, but increased SOC concentration. The b, v, and SOC concentration were potential predictors of CI; whereas b and SOC concentration were of shear strength (r2 > 0.42; P < 0.01). Results show that landscape positions had small effect, but management, particularly manuring, had large and significant effects on soil strength and SOC concentration.

Blanco-Canqui, H; Lal, Rattan; Owen, L B.; Post, W M.; Izaurralde, R Cesar C.

2005-04-01

81

Soil Carbon Changes in Transitional Grain Crop Production Systems in South Dakota  

NASA Astrophysics Data System (ADS)

Corn-C (Zea Mays L.), soybean-S (Glycine max L.) and spring wheat-W (Triticum aestivum L.) crops were seeded as a component of either a C-S, S-W, or C-S-W crop rotation on silt-loam textured soils ranging from 3.0-5.0% organic matter. Conservation tillage(chisel plow-field cultivator) was applied to half of the plots. The other plots were direct seeded as a no-till (zero-tillage) treatment. Grain yield and surface crop residues were weighed from each treatment plot. Crop residue (stover and straw) was removed from half of the plots. After four years, soil samples were removed at various increments of depth and soil organic carbon (C) and nitrogen (N) was measured. The ranking of crop residue weights occurred by the order corn>>soybean>wheat. Surface residue accumulation was also greatest with residue treatments that were returned to the plots, those rotations in which maize was a component, and those without tillage. Mean soil organic carbon levels in the 0-7.5cm depth decreased from 3.41% to 3.19% (- 0.22%) with conventional tillage (chisel plow/field cultivator) as compared to a decrease from 3.19% to 3.05% (-0.14%) in plots without tillage over a four year period. Organic carbon in the 0-7.5cm depth decreased from 3.21% to 3.01% (- 0.20%) after residue removed as compared to a decrease from 3.39% to 3.23% (-0.17%) in plots without tillage applied after four years. The soil C:N ratio (0-7.5cm) decreased from 10.63 to 10.37 (-0.26 (unitless)) in the tilled plots over a four-year period. Soil C:N ratio at the 0-7.5cm depth decreased from 10.72 to 10.04 (-0.68) in the no-till plots over a four year period. Differences in the soil C:N ratio comparing residue removed and residue returned were similar (-0.51 vs. -0.43 respectively). These soils are highly buffered for organic carbon changes. Many cropping cycles are required to determine how soil carbon storage is significantly impacted by production systems.

Woodard, H. J.

2004-12-01

82

Effect of Plowing Speed and Soil Moisture Content on the Voluminal Deformation of the Soil Body (Wplyw Szybkosci Orki i Wilgotnosci Gleby na Prace jej Odksztalcenia Objetosciowego).  

National Technical Information Service (NTIS)

The objective of the study was to investigate the work of the voluminal deformation of the soil body as a function of two essential factors, namely, the speed of the implement and the soil moisture content. The study is not, however, intended for a direct...

J. Haman

1975-01-01

83

Describing soil surface microrelief by crossover length and fractal dimension  

NASA Astrophysics Data System (ADS)

Accurate description of soil surface topography is essential because different tillage tools produce different soil surface roughness conditions, which in turn affects many processes across the soil surface boundary. Advantages of fractal analysis in soil microrelief assessment have been recognised but the use of fractal indices in practice remains challenging. There is also little information on how soil surface roughness decays under natural rainfall conditions. The objectives of this work were to investigate the decay of initial surface roughness induced by natural rainfall under different soil tillage systems and to compare the performances of a classical statistical index and fractal microrelief indices. Field experiments were performed on an Oxisol at Campinas, São Paulo State (Brazil). Six tillage treatments, namely, disc harrow, disc plow, chisel plow, disc harrow + disc level, disc plow + disc level and chisel plow + disc level were tested. Measurements were made four times, firstly just after tillage and subsequently with increasing amounts of natural rainfall. Duplicated measurements were taken per treatment and date, yielding a total of 48 experimental surfaces. The sampling scheme was a square grid with 25×25 mm point spacing and the plot size was 1350×1350 mm, so that each data set consisted of 3025 individual elevation points. Statistical and fractal indices were calculated both for oriented and random roughness conditions, i.e. after height reading have been corrected for slope and for slope and tillage tool marks. The main drawback of the standard statistical index random roughness, RR, lies in its no spatial nature. The fractal approach requires two indices, fractal dimension, D, which describes how roughness changes with scale, and crossover length, l, specifying the variance of surface microrelief at a reference scale. Fractal parameters D and l, were estimated by two independent self-affine models, semivariogram (SMV) and local root mean square (RMS). Both algorithms, SMV and RMS, gave equivalent results for D and l indices, irrespective of trend removal procedure, even if some bias was present which is in accordance with previous work. Treatments with two tillage operations had the greatest D values, irrespective of evolution stage under rainfall and trend removal procedure. Primary tillage had the greatest initial values of RR and l. Differences in D values between treatments with primary tillage and those with two successive tillage operations were significant for oriented but not for random conditions. The statistical index RR and the fractal indices l and D decreased with increasing cumulative rainfall following different patterns. The l and D decay from initial value was very sharp after the first 24.4 mm cumulative rainfall. For five out of six tillage treatments a significant relationship between D and l was found for the random microrelief conditions allowing a covariance analysis. It was concluded that using RR or l together with D best allow joint description of vertical and horizontal soil roughness variations.

Vidal Vázquez, E.; Miranda, J. G. V.; Paz González, A.

2007-05-01

84

Management factors affecting ammonia volatilization from land-applied cattle slurry in the Mid-Atlantic USA.  

PubMed

Ammonia (NH3) volatilization commonly causes a substantial loss of crop-available N from surface-applied cattle slurry. Field studies were conducted with small wind tunnels to assess the effect of management factors on NH3 volatilization. Two studies compared NH3 volatilization from grass sward and bare soil. The average total NH3 loss was 1.5 times greater from slurry applied to grass sward. Two studies examined the effect of slurry dry matter (DM) content on NH3 loss under hot, summer conditions in Maryland, USA. Slurry DM contents were between 54 and 134 g kg(-1). Dry matter content did not affect total NH3 loss, but did influence the time course of NH3 loss. Higher DM content slurries had relatively higher rates of NH3 volatilization during the first 12 to 24 h, but lower rates thereafter. Under the hot conditions, the higher DM content slurries appeared to dry and crust more rapidly causing smaller rates of NH3 volatilization after 12 to 24 h, which offset the earlier positive effects of DM content on NH3 volatilization. Three studies compared immediate incorporation with different tillage implements. Total NH3 loss from unincorporated slurry was 45% of applied slurry NH4+-N, while losses following immediate incorporation with a moldboard plow, tandem-disk harrow, or chisel plow were, respectively, 0 to 3, 2 to 8, and 8 to 12%. These ground cover and DM content data can be used to improve predictions of NH3 loss under specific farming conditions. The immediate incorporation data demonstrate management practices that can reduce NH3 volatilization, which can improve slurry N utilization in crop-forage production. PMID:12175054

Thompson, R B; Meisinger, J J

2002-01-01

85

Tillage, Mulch and N Fertilizer Affect Emissions of CO2 under the Rain Fed Condition  

PubMed Central

A two year (2010–2012) study was conducted to assess the effects of different agronomic management practices on the emissions of CO2 from a field of non-irrigated wheat planted on China's Loess Plateau. Management practices included four tillage methods i.e. T1: (chisel plow tillage), T2: (zero-tillage), T3: (rotary tillage) and T4: (mold board plow tillage), 2 mulch levels i.e., M0 (no corn residue mulch) and M1 (application of corn residue mulch) and 5 levels of N fertilizer (0, 80, 160, 240, 320 kg N/ha). A factorial experiment having a strip split-split arrangement, with tillage methods in the main plots, mulch levels in the sub plots and N-fertilizer levels in the sub-sub plots with three replicates, was used for this study. The CO2 data were recorded three times per week using a portable GXH-3010E1 gas analyzer. The highest CO2 emissions were recorded following rotary tillage, compared to the lowest emissions from the zero tillage planting method. The lowest emissions were recorded at the 160 kg N/ha, fertilizer level. Higher CO2 emissions were recorded during the cropping year 2010–11 relative to the year 2011–12. During cropping year 2010–11, applications of corn residue mulch significantly increased CO2 emissions in comparison to the non-mulched treatments, and during the year 2011–12, equal emissions were recorded for both types of mulch treatments. Higher CO2 emissions were recorded immediately after the tillage operations. Different environmental factors, i.e., rain, air temperatures, soil temperatures and soil moistures, had significant effects on the CO2 emissions. We conclude that conservation tillage practices, i.e., zero tillage, the use of corn residue mulch and optimum N fertilizer use, can reduce CO2 emissions, give better yields and provide environmentally friendly options.

Tanveer, Sikander Khan; Wen, Xiaoxia; Lu, Xing Li; Zhang, Junli; Liao, Yuncheng

2013-01-01

86

Tillage, mulch and N fertilizer affect emissions of CO2 under the rain fed condition.  

PubMed

A two year (2010-2012) study was conducted to assess the effects of different agronomic management practices on the emissions of CO2 from a field of non-irrigated wheat planted on China's Loess Plateau. Management practices included four tillage methods i.e. T1: (chisel plow tillage), T2: (zero-tillage), T3: (rotary tillage) and T4: (mold board plow tillage), 2 mulch levels i.e., M0 (no corn residue mulch) and M1 (application of corn residue mulch) and 5 levels of N fertilizer (0, 80, 160, 240, 320 kg N/ha). A factorial experiment having a strip split-split arrangement, with tillage methods in the main plots, mulch levels in the sub plots and N-fertilizer levels in the sub-sub plots with three replicates, was used for this study. The CO2 data were recorded three times per week using a portable GXH-3010E1 gas analyzer. The highest CO2 emissions were recorded following rotary tillage, compared to the lowest emissions from the zero tillage planting method. The lowest emissions were recorded at the 160 kg N/ha, fertilizer level. Higher CO2 emissions were recorded during the cropping year 2010-11 relative to the year 2011-12. During cropping year 2010-11, applications of corn residue mulch significantly increased CO2 emissions in comparison to the non-mulched treatments, and during the year 2011-12, equal emissions were recorded for both types of mulch treatments. Higher CO2 emissions were recorded immediately after the tillage operations. Different environmental factors, i.e., rain, air temperatures, soil temperatures and soil moistures, had significant effects on the CO2 emissions. We conclude that conservation tillage practices, i.e., zero tillage, the use of corn residue mulch and optimum N fertilizer use, can reduce CO2 emissions, give better yields and provide environmentally friendly options. PMID:24086256

Tanveer, Sikander Khan; Wen, Xiaoxia; Lu, Xing Li; Zhang, Junli; Liao, Yuncheng

2013-01-01

87

Effects of Crop Rotation, N Management, Tillage, and Controlled Drainage on nitrate-N Loss in Drain Flow  

NASA Astrophysics Data System (ADS)

Accurate simulation of agricultural management effects on N loss in tile drainage is vitally important for understanding hypoxia in the Gulf of Mexico. An experimental study was initiated in 1978 at Nashua, Iowa of the USA to study long-term effects of tillage, crop rotation, and N management practices on subsurface drainage flow and associated N losses. The Root Zone Water Quality Model (RZWQM) was applied to evaluate management effects (tillage, crop rotation, N application, and controlled drainage) on N loss in drain flow. RZWQM simulated the observed increase in N concentration in drain flow with increasing tillage intensity from NT (no-till) to RT (ridge till) to CP (chisel plow) and to MP (moldboard plow). It also adequately simulated tillage effects on yearly drain flow and yearly N loss in drain flow. On the other hand, RZWQM adequately simulated lower yearly drain flow and lower flow-weighted N concentration in drain flow under CS (corn-soybean) and SC (soybean-corn) than under CC (continuous corn). The model also simulated higher N loss from fertilizer-N applications than from manure-N applications. Applying the newly suggested N management practice for the Midwest of controlled drainage, the model simulated a 30% reduction in drain flow and a 29% decrease in N losses in drain flow under controlled drainage (CD) compared to free drainage (FD). With most of the simulations in reasonably close agreement with observations, we concluded that RZWQM is a promising tool for quantifying the relative effects of tillage, crop rotation, N application, and controlled drainage on N loss in drainage flow. Further improvements on simulated management effects on N mineralization and plant N uptake are needed, however.

Ma, L.; Malone, R.; Ahuja, L.; Kanwar, R. S.

2007-12-01

88

Biomass Production and Soil Carbon Level Changes in Various Tillage, Residue Management, and Cropping Systems in Moderately High Organic Matter Soils in Eastern South Dakota, U.S.A.  

NASA Astrophysics Data System (ADS)

A four-year replicated field study was conducted in eastern South Dakota to assess the impact of maize (Zea mays L.), soybean (Glycine max L.), and spring wheat (Triticum aestivum L.) on crop residue accumulation and soil carbon when various tillage, crop residue management, and crop rotation scenarios were applied. Before planting, half the plots were chisel plowed and harrowed (tilled vs. no-till treatments). Corn-soybean, soybean-wheat, or corn-wheat-soybean rotations were established (rotation treatments). After grain harvest, crop residues were removed on half of the plots (residue-removed vs. residue-retained treatments). The range of initial soil carbon levels (loss by ignition method) for the 0-15cm depth was 1.7-3.0%. Post-harvest crop residue accumulation was greatest for the residue-retained treatment compared to the residue-removed treatment and for the no-till treatment compared to the tilled treatment. In addition, surface biomass accumulation was greatest when maize was part of a crop rotation. Maize can produce greater levels of biomass compared to either spring wheat or soybean. The least surface biomass accumulation was measured in the soybean-wheat rotation.

Woodard, H. J.; Bly, A.

2003-12-01

89

A Survival Guide for Winter's Threats  

MedlinePLUS

... Docs offer tips for avoiding injuries while shoveling snow, walking on icy sidewalks and streets (*this news ... bones, muscle tears, sprains and strains from shoveling snow or falling on icy sidewalks and streets. Orthopedic ...

90

Artificial Cervical Disc Replacement Improves Mobility  

MedlinePLUS Videos and Cool Tools

... chisels to create the keel channels. First, the primary chisel is inserted over the trial and advanced ... screen and open the door to informed medical care. “OR Live,” the vision of improving health.

91

Area terrace pit coal mining systems: volume 2--appendices. Open file report (final) Sep 1977-Jul 1980  

SciTech Connect

This report is principally concerned with the engineering and economic feasibility of area surface coal mining systems other than draglines. This analysis evaluates shovel-trucks, shovel-crusher-conveyors, and shovel-rail excavation and haulage systems for an assortment of geologic environments and production rates in the Powder River Basin (PRB). Shovel-trucks, front-end loader-trucks, and shovel-crusher-conveyors were studied in a multiseam, dipping geologic area of the Four Corners region. The Texas lignite engineering and economic research involved bucket-wheel excavators (BWE), BWE-backhoes, and scraper-backhoe combinations for overburden and coal excavation.

Leonard, F.; Simon, C.; Stoddard, M.; Verma, M.; White, M.

1980-10-01

92

Effect of Conversion from Natural Grassland to Arable Land on Soil Carbon Reserve in the Argentinean Rolling Pampas  

NASA Astrophysics Data System (ADS)

The evaluation of the effect of land use change on accumulation of soil organic carbon (SOC) requires reliable data obtained from georeferenced sites with land use history records. The purpose of this study was to evaluate long term changes in the reserves of SOC in a typical Argiudol of the Pergamino series after the introduction of agriculture. Measures of soil organic carbon concentration and bulk density of Ap and A12 horizons were carried out in three sites of the Pergamino County (N of Buenos Aires province): a reference field with untilled pristine soil (33° 57' S; 60° 34' W), a field with 31 years (1980-2011) of agriculture (31Y) located next to the former, and a third field (33° 46' S; 60° 37' W) with 80 years (1910/1990) of agriculture (80Y). 31Y has been under continuous soybean cultivation with conventional tillage (CT) that consists of moldboard plow or double disk harrowing. At 80K the cultivation sequence was: 44 years of corn + 9 years of flax + 2 years of wheat + 17 years of wheat/soybean double cropping + 1 year of lentil; mostly under CT, some years under chisel plow during the 70's and a few years under zero tillage in soybean after wheat sown with conventional tillage during the 80's. Before the introduction of mechanical harvesting (1947) crop residues were burnt as well as the wheat stubble during the conventional double cropping period (1970-1980). Soil texture (23±1% clay, with predominance of illite) and field slopes (<0.5%) were similar in the three sites. Nitrogen and phosphorus fertilization rates were minimal due to the low crop response. The results are expressed in Mg ha-1 for an A soil horizon mass of 2500 Mg ha-1. The introduction of agriculture decreased SOC stock: 31Y varied from 68.3 to 40.1 Mg ha-1 (41.3% loss) and 80Y from 68.3 to 47.2 Mg ha-1 (30% loss). The SOC loss was the result of the mineralization of a large amount labile SOC present in the pristine soil and low annual additions of carbon issued from crop residue (3.5 and 3.3 Mg ha-1 corresponding to 31Y and 80Y, respectively). The lower loss of carbon in 80Y compared to 30Y can be explained by the accumulation of stable SOC fractions produced by the burnt stubble. We conclude that current agricultural systems of the Rolling Pampas are not sustainable.

Andriulo, A. E.; Irizar, A. B.; Mary, B.; Wilson, M. G.

2012-04-01

93

Phosphorus leaching under a restored tallgrass prairie and corn agroecosystems.  

PubMed

Most studies of phosphorus (P) movement in soil have based their conclusions on patterns of extractable soil P as a function of depth, which has led to the assumption that no substantial leaching loss occurs because of high P-fixation capacity in mineral soils. Few studies have involved high-quality leachate samples collected below the root zone; rather, most have involved tile drainage systems. Equilibrium-tension lysimeters installed at a depth of 1.4 m were used to evaluate and compare P leaching from a restored tallgrass prairie and corn (Zea mays L.) agroecosystems on Plano silt loam soil (fine-silty, mixed, superactive, mesic Typic Argiudoll) in southcentral Wisconsin during a 5-yr period. The corn agroecosystem treatments included nitrogen (N)-fertilized (f) or N-unfertilized (nf) and no-tillage (NT) or chisel-plowed (CP). Mean volume-weighted molybdate-reactive phosphorus (MRP) and total dissolved phosphorus (TDP) concentrations were similar within replicate samples, but always higher in NTf corn than in the prairie or CPf corn systems, though drainage from the CPf corn was always higher than from the NTf corn system. Water-extractable soil P concentrations at any given depth were not positively correlated with leachate concentrations, suggesting that macropore flow causes infiltrating runoff to preferentially bypass the bulk of the soil matrix. Leachate-P concentrations from the natural and managed agroecosystems exceeded 0.01 mg P L(-1) and leaching losses were significantly higher from N-fertilized corn, regardless of tillage, than from the prairie or N-unfertilized corn systems, from which leachate-P concentrations and loads were similar. Increased root growth from N fertilization could cause more macropore formation, preferential flow, and P mineralization from decaying roots compared with N-unfertilized systems, which could contribute to a N-fertilization effect on P leaching. PMID:12026080

Brye, K R; Andraski, T W; Jarrell, W M; Bundy, L G; Norman, J M

2002-01-01

94

Seasonal dynamics of CO2 efflux in soils amended with composted and thermally-dried sludge as affected by soil tillage systems in a semi-arid agroecosystem  

NASA Astrophysics Data System (ADS)

In semi-arid agricultural soils, seasonal dynamic of soil CO2 efflux (SCE) is highly variable. Based on soil respiration measurements the effects of different management systems (moldboard plowing, chisel and no-tillage) and the application of composted sludge (CS) and thermally-dried sewage sludge (TSS) was investigated in a long-term field experiment (28 years) conducted on a sandy-loam soil at the experimental station 'La Higueruela' (40o 03'N, 4o 24'W). Both organic amendments were applied at a rate of 30 Mg ha-1 prior to tillage practices. Unamended soils were used as control for each tillage system. SCE was moderate in late spring (2.2-11.8 ?mol CO2 m-2 s-1) when amendments were applied and tillage was performed, markedly decreased in summer (0.4-3.2 ?mol CO2 m-2 s-1), following a moderate increase in autumn (3.4-14.1 ?mol CO2 m-2 s-1), rising sharply in October (5.6-39.8 ?mol CO2 m-2 s-1 ). In winter, SCE was low (0.6-6.5 ?mol CO2 m-2 s-1). In general, SCE was greater in chisel and moldboard tilled soils, and in CS and particularly TSS-amended soils, due to the addition of labile C with these amendments, meanwhile no-tillage soils exhibited smaller increases in C efflux throughout the seasons. Soil temperature controlled the seasonal variations of SCE. In summer, when drought occurs, a general decrease of SCE was observed due to a deficit in soil water content. After drought period SCE jumped to high values in response to rain events ('Birch effect') that changed soil moisture conditions. Soil drying in summer and rewetting in autumn may promotes some changes on the structure of soil microbial community, affecting associated metabolic processes, and enhancing a rapid mineralization of water-soluble organic C compounds and/or dead microbial biomass that acts as an energy source for soil microorganisms. To assess the effects of tillage and amendments on SCE, Q10 values were calculated. Data were grouped into three groups according to soil moisture (0.03-0.10 m3m-3, 0-11-0.21 m3m-3, 0.22-0.30 m3m-3). In general, Q10 values were lower at elevated temperatures when soil moisture contents decreased, confirming that SCE is less sensitive to soil temperature during drought periods. Q10 values were higher in moldboard and chisel tilled soils, possibly due to the incorporation of residues into soil and the increase of soil C substrate, meanwhile in no-tillage part of the organic C pools are likely protected from microorganisms by physico-chemical mechanisms. TSS-amended soils exhibited higher Q10 values than CS, pointing that the biochemical lability of the organic C added with amendments exerts an influence on SCE. Acknowledgements: this research was supported by the Spanish CICYT, Project no. CTM2011-25557.

García-Gil, Juan Carlos; Soler-Rovira, Pedro; López-de-Sa, Esther G.; Polo, Alfredo

2014-05-01

95

Real promise or false hope: DOE's title XVII loan Guarantee  

SciTech Connect

While the American Recovery and Reinvestment Act of 2009 expanded the DOE loan guarantee program to include certain ''shovel-ready'' projects, and appropriated $6 billion to cover the credit subsidy cost associated with these projects, it failed to resolve some of the most pressing problems facing the program. Here are some recommendations that may finally get some shovels in the ground. (author)

Massouh, Jennifer F.; Cannon, George D. Jr.; Logan, Suzanne M.; Schwartz, David L.

2009-05-15

96

Caelum  

NASA Astrophysics Data System (ADS)

(the Chisel; abbrev. Cae, gen. Caeli; area 125 sq. deg.) A southern constellation that lies between Eridanus and Columba, and culminates at midnight in late November. It was named Caela Sculptoris (the Sculptor's Chisels) by the French astronomer Nicolas L de Lacaille (1713-62), who charted the southern sky in 1751-2. The shortened form was adopted by the IAU in 1922....

Murdin, P.

2000-11-01

97

Distribution of organic carbon in physical fractions of soils as affected by agricultural management  

SciTech Connect

Soil organic carbon (SOC) is distributed heterogeneously among different-sized primary particles and aggregates. Further, the SOC associated with different physical fractions respond differently to managements. Therefore, this study was conducted with the objective to quantify the SOC associated with all the three structural levels of SOC (particulate organic matter, soil separates and aggregate-size fractions) as influenced by long-term change in management. The study also aims at reevaluating the concept that the SOC sink capacity of individual size-fractions is limited. Long-term tillage and crop rotation effects on distribution of SOC among fractions were compared with soil from adjacent undisturbed area under native vegetation for the mixed, mesic, Typic Fragiudalf of Wooster, OH. Forty five years of no-till (NT) management resulted in more SOC accumulation in soil surface (0 7.5 cm) than in chisel tillage and plow tillage (PT) treatments. However, PT at this site resulted in a redistribution of SOC from surface to deeper soil layers. The soils under continuous corn accumulated significantly more SOC than those under corn soybean rotation at 7.5 45 cm depth. Although soil texture was dominated by the silt-sized particles, most of the SOC pool was associated with the clay fraction. Compared to PT, the NT treatment resulted in (i) significantly higher proportion of large macroaggregates (>2,000 m) and (ii) 1.5 2.8 times higher SOC concentrations in all aggregate-size classes. A comparative evaluation using radar graphs indicated that among the physical fractions, the SOC associated with sand and silt fractions quickly changed with a land use conversion from native vegetation to agricultural crops. A key finding of this study is the assessment of SOC sink capacity of individual fractions, which revealed that the clay fraction of agricultural soils continues to accumulate more SOC, albeit at a slower rate, with progressive increase in total SOC concentration. However, the clay fraction of soil under native woodlot showed an indication for SOC saturation. The data presented in this study from all the three structural levels of SOC would be helpful for refining the conceptual pool definitions of the current soil organic matter prediction models.

Sindhu, Jagadamma [Oak Ridge National Laboratory (ORNL); Lal, Dr. Rattan [Ohio State University, The, Columbus

2010-08-01

98

Long-term Differences in Tillage and Land Use Affect Intra-aggregate Pore Heterogeneity  

SciTech Connect

Recent advances in computed tomography provide measurement tools to study internal structures of soil aggregates at micrometer resolutions and to improve our understanding of specific mechanisms of various soil processes. Fractal analysis is one of the data analysis tools that can be helpful in evaluating heterogeneity of the intra-aggregate internal structures. The goal of this study was to examine how long-term tillage and land use differences affect intra-aggregate pore heterogeneity. The specific objectives were: (i) to develop an approach to enhance utility of box-counting fractal dimension in characterizing intra-aggregate pore heterogeneity; (ii) to examine intra-aggregate pores in macro-aggregates (4-6 mm in size) using the computed tomography scanning and fractal analysis, and (iii) to compare heterogeneity of intra-aggregate pore space in aggregates from loamy Alfisol soil subjected to 20 yr of contrasting management practices, namely, conventional tillage (chisel plow) (CT), no-till (NT), and native succession vegetation (NS). Three-dimensional images of the intact aggregates were obtained with a resolution of 14.6 {micro}m at the Advanced Photon Source, Argonne National Laboratory, Argonne, IL. Proposed box-counting fractal dimension normalization was successfully implemented to estimate heterogeneity of pore voxel distributions without bias associated with different porosities in soil aggregates. The aggregates from all three studied treatments had higher porosity associated with large (>100 {micro}m) pores present in their centers than in their exteriors. Pores 15 to 60 {micro}m were equally abundant throughout entire aggregates but their distributions were more heterogeneous in aggregate interiors. The CT aggregates had greater numbers of pores 15 to 60 {micro}m than NT and NS. Distribution of pore voxels belonging to large pores was most heterogeneous in the aggregates from NS, followed by NT and by CT. This result was consistent with presence of very large pores associated with former root channels in NT and NS aggregates. Our findings indicate that mechanisms of macro-aggregate formation might differ in their importance in different land use and management practices.

Kravchenko, A.N.; Wang, A.N.W.; Smucker, A.J.M.; Rivers, M.L. (MSU); (UC)

2012-10-25

99

Influence for Soil Environment by Continuing use of Biodegradable Plastic  

Microsoft Academic Search

The influence on soil environment by continuing use of the biodegradable plastic films (biodegradable mulching films) in farmland\\u000a was investigated. The difference was not seen in the amount of soil bacteria between mulching film plowing sections and non-plowing\\u000a sections. The total bacteria amount did not increase by the effect of plowing the biodegradable mulching film. Poly-(butylene\\u000a succinate and adipate) (PBSA)

Akihiko Masui; Satoshi Ikawa; Nobuaki Fujiwara; Hiroaki Hirai

100

Winter, Your Car, and You  

MedlinePLUS

... spark plugs. • Checking the air, fuel and emission filters, and the PCV valve. • Inspecting the distributor. • Checking ... shovel • Jumper cables • Tow and tire chains • A bag of salt or cat litter • Toolkit Essential Supplies ...

101

GY SAMPLING THEORY IN ENVIRONMENTAL STUDIES 1: ASSESSING SOIL SPLITTING PROTOCOLS  

EPA Science Inventory

Five soil sample splitting methods (riffle splitting, paper cone riffle splitting, fractional shoveling, coning and quartering, and grab sampling) were evaluated with synthetic samples to verify Pierre Gy sampling theory expectations. Individually prepared samples consisting of l...

102

155. Credit ER. Hand cleaning and trimming of Coleman canal ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

155. Credit ER. Hand cleaning and trimming of Coleman canal after excavation by steam shovel. (ER, v. 64 1911 p. 701). - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

103

L'Entretient des Canaux de Drainage a Ciel Ouvert (Some Aspects of an Open Drainage Canal and Maintenance Program).  

National Technical Information Service (NTIS)

This booklet contains many aspects of a drainage program. Topics discussed include principal causes for the failure of open drainage canals, recent research on the mechanics of open drainage canal maintenance, and the Ahmed Davis shovel. Included in the b...

W. J. Davis

1978-01-01

104

30 CFR 56.12039 - Protection of surplus trailing cables.  

Code of Federal Regulations, 2013 CFR

...DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Electricity § 56.12039 Protection of surplus trailing cables. Surplus trailing cables to shovels, cranes and similar...

2013-07-01

105

Area terrace pit coal mining systems: volume 1--technical and economic evaluation of terrace pit mining systems. Open file report (final) Sep 1977-Jul 1980  

SciTech Connect

This report is principally concerned with the engineering and economic feasibility of area surface coal mining systems other than draglines. This analysis evaluates shovel-trucks, shovel-crusher-conveyors, and shovel-rail excavation and haulage systems for an assortment of geologic environments and production rates in the Powder River Basin (PRB). Shovel-trucks, front-end loader-trucks, and shovel-crusher conveyors were studied in a multiseam, dipping geologic area of the Four Corners region. The Texas lignite engineering and economic research involved bucket-wheel excavators (BWE), BWE-backhoes, and scraper-backhoe combinations for overburden and coal excavation. The PRB truck-shovel study utilized the most recent computer simulation available in both the design and cost analysis. Detailed engineering analysis, followed by in-depth operating costs result in a complete evaluation of each mining system. Cost comparisons of the different mining systems under similar geologic and production constraints are presented to illustrate the estimated capital investment and production costs per ton of coal and bank cubic yard of overburden.

Leonard, F.; Simon, C.; Stoddard, M.; Verma, M.; White, M.

1980-10-01

106

Isolation of guard cells from fresh epidermis using a piezo-power micro-dissection system with vibration-attenuated needles.  

PubMed

The Eppendorf Piezo-Power Microdissection (PPMD) system uses a tungsten needle (MicroChisel) oscillating in a forward-backward (vertical) mode to cut cells from surrounding tissue. This technology competes with laser-based dissection systems, which offer high accuracy and precision, but are more expensive and require fixed tissue. In contrast, PPMD systems can dissect freshly prepared tissue, but their accuracy and precision is lower due to unwanted lateral vibrations of the MicroChisel. Especially in tissues where elasticity is high, these vibrations can limit the cutting resolution or hamper the dissection. Here we describe a cost-efficient and simple glass capillary-encapsulation modification of MicroChisels for effective attenuation of lateral vibrations. The use of modified MicroChisels enables accurate and precise tissue dissection from highly elastic material. PMID:20078431

Terpitz, Ulrich; Zimmermann, Dirk

2010-01-01

107

Chin augmentation - series (image)  

MedlinePLUS

The mandible, or lower jaw, determines much of the facial profile and the alignment of the upper and lower ... an osteotomy) is made through the jaw bone (mandible) with a bone saw or chisel. The lower ...

108

21 CFR 878.4820 - Surgical instrument motors and accessories/attachments.  

Code of Federal Regulations, 2010 CFR

...devices intended for use during surgical procedures to provide power to operate various accessories or attachments to cut hard tissue or bone and soft tissue. Accessories or attachments may include a bur, chisel (osteotome), dermabrasion...

2010-04-01

109

21 CFR 878.4820 - Surgical instrument motors and accessories/attachments.  

Code of Federal Regulations, 2010 CFR

...devices intended for use during surgical procedures to provide power to operate various accessories or attachments to cut hard tissue or bone and soft tissue. Accessories or attachments may include a bur, chisel (osteotome), dermabrasion...

2009-04-01

110

Techniques for coherent phonon excitation and stimulated Brillouin scattering  

NASA Astrophysics Data System (ADS)

The basic principle of a rotating chisel-shaped phonon coupling and detection probe, believed to be novel, is presented for the measurement of coherent phonon propagation and interaction characteristics.

Hsu, Hsiung; Wanuga, Stephen; Tehon, Stephen W.; Li, Tong-ning; Xu, Yue

2002-07-01

111

Mixed Minefield Modeling.  

National Technical Information Service (NTIS)

The purpose of this section is to present a model for analyzing the effectiveness of mine clearing plows mounted in front of the tracks of a tank in a AM minefield. The plow's function is to sweep AM mines away from the path of the tank's tracks thereby p...

M. Messinger

1973-01-01

112

Ryegrass Cover Crop Effects on Nitrate Leaching in Spring Barley Fertilized with 15 NH4 15 NO3  

Microsoft Academic Search

vated in early autumn and plowed in the spring (Lewan, 1994). However, during the fourth year, after the rye- Cover crops are a management option to reduce NO3 leaching grass was plowed under and not replaced by another under cereal grain production. A 2-yr field lysimeter study was estab- lished in Uppsala, Sweden, to evaluate the effect of a perennial

Lars F. Bergstrom; William E. Jokela

113

Tillage impacts on soil microbial biomass C, N and P, earthworms and agronomy after two years of cropping following permanent pasture in New Zealand  

Microsoft Academic Search

Conversion of pasture land to crop rotation by plow tillage and reversion to pasture for replenishment of nutrients is a common practice in New Zealand. It is known that plow tillage decreases soil organic matter and causes biological degradation. The objective of this study was to investigate the effects of tillage practices on soil microbial biomass carbon (MBC), microbial biomass

T Aslam; M. A Choudhary; S Saggar

1999-01-01

114

Cutting Through Soil  

NSDL National Science Digital Library

Students pretend they are agricultural engineers during the colonial period and design a miniature plow that cuts through a "field" of soil. They are introduced to the engineering design process and learn of several famous historical figures who contributed to plow design.

Integrated Teaching And Learning Program

115

Determinants of tillage frequency among smallholder farmers in two semi-arid areas in Ethiopia  

NASA Astrophysics Data System (ADS)

Traditional tillage systems practiced by farmers in semi-arid regions of Ethiopia are characterized by repeated and cross plowing with an indigenous plow called Maresha. Repeated and cross plowing have led to land degradation. Conservation tillage systems that advocate minimum soil disturbance can alleviate land degradation problems. However, before introducing reduced tillage systems, it was found necessary to study why farmers undertake repeated plowing. The study was undertaken in two semi-arid areas called Melkawoba and Wulinchity located in the central rift valley of Ethiopia and on two major crops; Tef ( Eragrostis Tef (Zucc.)) and maize ( Zea mays XX). Fifty farmers from each area were randomly selected and interviewed using a structured questionnaire. The results showed that farmers in the study area plow repeatedly in order to completely disturb unplowed strips of land left between adjacent furrows. Unplowed strips are the results of the V-shaped furrows created by the Maresha plow. Farmers generally do not plow before the soil is wetted by rainfall. Wetting and drying cycles due to dry spells occurring between rainfall events force farmers to plow frequently to avoid moisture losses through surface runoff, evaporation and weed transpiration. Tef fields are plowed 4-5 times while maize fields are plowed 3-4 times. Tillage frequency increased with the education level and experience of farmers; with their perception about the purpose of tillage such as moisture conservation, weed control and soil warming; and with resource availability such as area of land and family labor. Tillage frequency was higher for Tef than for maize and in heavy soils than in light soils.

Temesgen, Melesse; Rockstrom, J.; Savenije, H. H. G.; Hoogmoed, W. B.; Alemu, Dawit

116

Land use and land management effects on soil organic carbon stock in Mediterranean agricultural areas (Southern Spain)  

NASA Astrophysics Data System (ADS)

INTRODUCTION Soils play a key role in the carbon geochemical cycle. Agriculture contributes to carbon sequestration through photosynthesis and the incorporation of carbon into carbohydrates. Soil management is one of the best tools for climate change mitigation. Small increases or decreases in soil carbon content due to changes in land use or management practices, may result in a significant net exchange of carbon between the soil carbon pool and the atmosphere. In the last decades arable crops (AC) have been transformed into olive grove cultivations (OG) or vineyards (V) in Mediterranean areas. A field study was conducted to determine long-term effects of land use change (LUC) (AC by OG and V) on soil organic carbon (SOC), total nitrogen (TN), C:N ratio and their stratification in Calcic-Chromic Luvisols (LVcc/cr) in Mediterranean conditions. MATERIAL AND METHODS An unirrigated farm in Montilla-Moriles (Córdoba, Spain) cultivated under conventional tillage (animal power with lightweight reversible plows and non-mineral fertilization or pesticides) was selected for study in 1965. In 1966, the farm was divided into three plots with three different uses (AC, OG and V). The preliminary analyses were realized in 1965 for AC (AC1), and the second analyses were realized in 2011 for AC (AC2 - winter crop rotation with annual wheat and barley, receiving mineral fertilization or pesticides), OG (annual passes with disk harrow and cultivator in the spring, followed by a tine harrow in the summer receiving mineral fertilization and weed control with residual herbicides), and V (with three or five chisel passes a year from early spring to early autumn with mineral fertilization or pesticides.). In all cases (AC1, AC2, OG and V) were collected soil entire profiles. Soil properties determined were: soil particle size, bulk density, SOC, TN, C:N ratio, stocks and SRs. The statistical significance of the differences in the variables between land use practices was tested using the Anderson-Darling test at each horizon or a combination of horizons for each soil type. RESULTS The LUC had a negative impact in the soil, reducing the SOC and TN stocks. The conversion from AC to V and OG involved the loss of the SOC stock (52.7% and 64.9% to V and OG respectively) and the loss of the TN stock (42.6% and 38.1% to V and OG respectively). The reduction of SOC by LUC, can be explained by a degraded process (due to vegetation losses and unsustainable soil management, which result in progressive impoverishment in the soil organic matter (OM) content, causing low productivity, which derived in unsuitable chemical properties) and by the reduced input of OM in cultivated soils, which reduced physical protection of soil and increased water erosion. However, 46 years of LUC had a positive effect in the soil, increasing the SR (in V and OG) of SOC, TN and C:N ratio (Parras-Alcántara et al., 2013). REFERENCES Parras-Alcántara, L., Martín-Carrillo, M., Lozano-García, B. 2013. Impacts of land use change in soil carbon and nitrogen in a Mediterranean agricultural area (Southern Spain). Solid Earth, 4: 167-177.

Parras-Alcántara, Luis; Lozano-García, Beatriz

2014-05-01

117

Made in Germany  

SciTech Connect

This supplement was prepared in collaboration with the Association of German Mining Machine Manufacturers within VDMA to give an overview of German manufacturers' contribution to the coal industry. It has 18 short papers and a VDMA vendor matrix and directory. Papers include details of MAN Takraf's surface mining equipment, hydraulic shovels and excavators from Komatsu, Liebherr and Terex O & K, Siemens motors and electric control technology in trucks, shovels etc., new technology from DBT, IBS and Wirth, and low emission engines and drives from Deutz and DaimlerCrysler. 2 figs.

NONE

2005-09-01

118

G-MG A Ton of Snow  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Eric and Julianne are shoveling snow. After an hour of hard work, Eric remarks ''I bet we have shoveled more than a ton of snow.'' Explain what measure...

119

78 FR 76389 - Notice of Passenger Facility Charge (PFC) Approvals and Disapprovals  

Federal Register 2010, 2011, 2012, 2013

...equipment--replace plow vehicles and spreaders. Acquire security equipment--security system card readers and security surveillance cameras. Replace security vehicles and equipment. Extend and rehabilitate apron (airline). Demolish...

2013-12-17

120

25 CFR 227.22 - Diligence and prevention of waste.  

Code of Federal Regulations, 2011 CFR

...supervisor relative to prevention of waste, and preservation of the property and the health and safety of workmen; bury all pipelines crossing tillable lands below plow depth unless other arrangements therefor are made with the superintendent; pay all...

2011-04-01

121

25 CFR 211.47 - Diligence, drainage and prevention of waste.  

Code of Federal Regulations, 2011 CFR

...expense, all reasonable orders and requirements of the authorized officer relative to prevention of waste; (h) Bury all pipelines crossing tillable lands below plow depth unless other arrangements are made with the Indian surface owner; and (i)...

2011-04-01

122

49 CFR 393.25 - Requirements for lamps other than head lamps.  

Code of Federal Regulations, 2013 CFR

...requirements specified in the SAE standards listed in paragraph (c) of this section. If motor vehicle equipment (e.g. , mirrors, snow plows, wrecker booms, backhoes, and winches) prevents compliance with this paragraph by any required lamp,...

2013-10-01

123

Methane and Dust Controls for Longwalls: Pocahontas No. 3 Coalbed, Grundy, Va.  

National Technical Information Service (NTIS)

The periphery of longwall panels in the Pocahontas No. 3 coalbed is characterized by a zone of reduced permeability that inhibits the natural drainage of methane. The buildup of gas pressure within large blocks causes methane problems during plowing opera...

A. Cetinbas J. Cervik M. G. Zabetakis R. P. Vinson

1974-01-01

124

76 FR 12405 - Notice of Passenger Facility Charge (PFC) Approvals and Disapprovals  

Federal Register 2010, 2011, 2012, 2013

...Projects Approved for Collection and Use: Tractor with snow blower and snow plow. Airport security and access control upgrades--design. Airport security and access control upgrades--construction. PFC application, amendments, and...

2011-03-07

125

4. CORNICE AND PARAPET DETAIL. IN THE CENTER IS AN ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. CORNICE AND PARAPET DETAIL. IN THE CENTER IS AN ANVIL AND A PLOW, SYMBOLIC TOOLS OF THE FARMERS AND MECHANICS - Farmers' & Mechanics' Bank, 427 Chestnut Street, Philadelphia, Philadelphia County, PA

126

29 CFR 779.371 - Some automobile, truck, and farm implement establishments may qualify for exemption under section...  

Code of Federal Regulations, 2013 CFR

...maintenance arrangement as in paragraph (c)(5) of this section is present. (e) Farm implement sales. Sales of farm machinery, such as equipment necessary for plowing, planting, thinning, weeding, fertilizing, irrigating, and...

2013-07-01

127

Visualization of Stress Distribution on Ultrasonic Vibration Aided Drilling Process  

NASA Astrophysics Data System (ADS)

The ultrasonically assisted machining is suitable to achieve sub-millimeter drilling on difficult-to-cut materials such as ceramics, hardened steel, glass and heat-resistant steel. However, it is difficult to observe the high-frequency and micron-scale phenomenon of ultrasonic cutting. In this report, high speed camera based on photoelastic analysis realized the visualization of stress distribution on drilling process. For the conventional drilling, the stress distribution diagram showed the intensive stress occurred under the chisel because the chisel edge of drill produces large plastic deformation. On the other hand, the ultrasonic drilling produced spread stress distribution and stress boundary far away from the chisel. Furthermore, chipping or cracking of inner wall of silica glass was influenced considerably by cutting fluid.

Isobe, Hiromi; Uehara, Yusuke; Okada, Manabu; Horiuchi, Tomio; Hara, Keisuke

128

Beta-Glucosidase Activity in Paddy Soils of the Taihu Lake Region, China 1 1 Project supported by the National Natural Science Foundation of China (No. 40371066) and the National Key Basic Research Support Foundation of China (No. G1999011808)  

Microsoft Academic Search

The profile distribution of ?-gulcosidase activity in twelve typical paddy soil profiles with high productivity in the Taihu Lake region of China were investigated. Activities of ?-gulcosidase in the plow layers were in the range of 52.68–137.02 ?g PNP g?1 soil h?1 with a mean of 89.22 ?g PNP g?1 soil h?1. However, most plow layers ranged from 70 to

Xiao-Chang WANG; Qin LU

2006-01-01

129

Studies on saline soils in Khon Kaen Region, Northeast Thailand  

Microsoft Academic Search

The effects of several amelioration treatments on the physical and chemical properties of the saline soils (Paleustult) in the Khon Kaen Region, Northeast Thailand, were studied. The application of CaSO4, CaCO3 converter slag, or compost into the plow layer, the placement of crude oil or rice husks below the plow layer and rice straw mulching were compared.The plots with these

Pongsiri Patcharapreecha; Bubpha Topark-Ngarm; Itsuo Goto; Makoto Kimura

1990-01-01

130

Seasonal variation of root distribution of irrigated, field-grown Russet Burbank potato  

Microsoft Academic Search

Root density of irrigated, field-grown Russet Burbank potatoes grown on Plainfield loamy sand was determined periodically\\u000a from soil core samples during the 1973 growing season. Total root length and weight also were measured.\\u000a \\u000a Under these growing conditions, the roots essentially were restricted to the plow layer in this soil, decreasing rapidly below\\u000a this depth. The root density in the plow

D. B. Lesczynski; C. B. Tanner

1976-01-01

131

Paramagnetic properties of humus acids of podzolic and bog-podzolic soils  

NASA Astrophysics Data System (ADS)

The contents of free radicals in preparations of humic and fulvic acids extracted from virgin and plowed podzolic, surface gleyic podzolic, and peaty podzolic-gleyic soils were determined. The concentration of paramagnetic centers in the humic acids was 1.5-2 times higher than that in the fulvic acids. The agricultural use decreases the paramagnetic activity of the humus compounds and promotes the accumulation of biothermodynamically stable organic compounds in the plow horizons.

Lodygin, E. D.; Beznosikov, V. A.; Chukov, S. N.

2007-07-01

132

Modified ridge splitting and bone expansion osteotomy for placement of dental implant in esthetic zone.  

PubMed

Ridge splitting with bone expansion is a technique of manipulation of bone to form receptor site for implant without removing any bone from the implant site. Maxillary bone has inherent quality of flexibility which can bemolded to desire location by using series of instrument namely chisels and osteotome. This further improves quality of bone all around implant, at the crest and apex both. This article describes a report of a clinical case with management of bucco-palatal ridge defect with modified ridge splitting and expansion osteotomy technique using chisel and osteotomes in an esthetic zone. PMID:24808709

Khairnar, Mayur S; Khairnar, Darshana; Bakshi, Kedar

2014-01-01

133

Modified ridge splitting and bone expansion osteotomy for placement of dental implant in esthetic zone  

PubMed Central

Ridge splitting with bone expansion is a technique of manipulation of bone to form receptor site for implant without removing any bone from the implant site. Maxillary bone has inherent quality of flexibility which can bemolded to desire location by using series of instrument namely chisels and osteotome. This further improves quality of bone all around implant, at the crest and apex both. This article describes a report of a clinical case with management of bucco-palatal ridge defect with modified ridge splitting and expansion osteotomy technique using chisel and osteotomes in an esthetic zone.

Khairnar, Mayur S.; Khairnar, Darshana; Bakshi, Kedar

2014-01-01

134

New Self-Convergent Programming Method for Multilevel AND Flash Memory  

NASA Astrophysics Data System (ADS)

A new self-convergent programming method for multilevel AND-type flash memory is described to accurately control the dispersion of the programmed threshold voltage which is caused by the deviation of the applied voltage or the FN tunneling current. Both channel initiated secondary electron injection (CHISEL) and avalanche hot electron injection (AHEI) following the edge FN electron ejection can be used as the self-convergent programming techniques. However, CHISEL is shown to be better than AHEI for self-convergent operation due to faster speed, lower voltage, lower power consumption, and better oxide reliability.

Yang, Evans; Wong, Wei-Jer; Wang, Yen-Sen; Shen, Rick; Hsu, Charles

1999-04-01

135

Development of A Cross-Pit Conveyor System (CPCS). Volume III.  

National Technical Information Service (NTIS)

The report describes the design of a conveyor system to be used in strip mining. The conveyor receives material from a dragline or stripping shovel and delivers it to the spoil pile. The unit extends the stripping depth capability of excavators and reduce...

1976-01-01

136

Surface mining of oil sands in Canada: Developments in productivity improvement  

SciTech Connect

A variety of equipment is used to surface mine oil sands, including bucket wheel excavators/conveyors, draglines, hydraulic shovels, and off-highway trucks. This paper examines the existing mining schemes and equipment used. Several proposals to improve mine productivity are presented.

Singhal, R.K.; Kolada, R.

1987-04-01

137

78 FR 25469 - Notice of Inventory Completion: University of South Alabama Center for Archaeological Studies...  

Federal Register 2010, 2011, 2012, 2013

...consisting of 9 molars, 2 molar fragments, 8 pre-molars, 4 canines, 2 shovel-shaped incisors, 1 proximal tibia shaft, 1 ulna...individuals, consisting of 16 molars, 10 premolars, 9 incisors, 7 canines, 61 unidentifiable tooth fragments, 1 rib fragment,...

2013-05-01

138

2006 Haulage & Loading Conference: big equipment, big crowd  

SciTech Connect

The theme of this year's Haulage and Loading Conference was 'Is better still better?' Most of the presenters either considered the effectiveness of bigger equipment or examined other strategies from various perspectives, based on their experiences. Papers were presented on trucks, shovels, loaders, excavators, haul road design and maintenance, and incorporating IT equipment. 5 photos.

NONE

2006-06-15

139

Complete Genome Sequence of a Reassortant H14N2 Avian Influenza Virus from California  

PubMed Central

We report the complete genome sequence of a reassortant H14N2 avian influenza virus isolated in 2011 from a northern shoveler in California. This introduced Eurasian subtype acquired seven segments from North American viruses and circulated in the Pacific Flyway 1 year after its detection in the Mississippi Flyway.

Schobel, Seth; Dugan, Vivien G.; Halpin, Rebecca; Lin, Xudong; Wentworth, David E.; Lindsay, LeAnn L.; Mertens, Eva; Plancarte, Magdalena

2013-01-01

140

19. Photocopied August 1978. CANAL SECTION I, LOOKING EAST, 1900, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. Photocopied August 1978. CANAL SECTION I, LOOKING EAST, 1900, WITH SEVERAL PARTIALLY SUBMERGED STEAM SHOVELS SHOWN IN THE FLOODED CANAL. ONE OF THE TEMPORARY BRIDGES CONSTRUCTED OVER THE CANAL RIGHT -OF-WAY IS VISIBLE IN THE BACKGROUND. (39) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

141

Complete Genome Sequence of a Reassortant H14N2 Avian Influenza Virus from California.  

PubMed

We report the complete genome sequence of a reassortant H14N2 avian influenza virus isolated in 2011 from a northern shoveler in California. This introduced Eurasian subtype acquired seven segments from North American viruses and circulated in the Pacific Flyway 1 year after its detection in the Mississippi Flyway. PMID:23908286

Boyce, Walter M; Schobel, Seth; Dugan, Vivien G; Halpin, Rebecca; Lin, Xudong; Wentworth, David E; Lindsay, Leann L; Mertens, Eva; Plancarte, Magdalena

2013-01-01

142

Cross-pit conveyor and end-around-conveyor continuous mining systems. [Coal mine  

Microsoft Academic Search

These systems will perform prebenching for draglines and shovels, reclamation of spoils without soil compaction, mining of surface coal seams that are beyond the normal dragline range, mining of multiple thin coal seams and cost efficient haulage. In addition to coal mining, these systems can be used in tar sands, phosphate, or other applications where large volumes of material must

K. L. Barden; T. I. Files; P. J. Gilewicz

1981-01-01

143

Telepresence information and remote-controlled task execution  

Microsoft Academic Search

We developed a remote-controlled system which enabled us to effectively control remote construction machinery such as a backhoe shovel, wheel dump and bulldozer using video images at a safe distance and in a comfortable environment. We used this system for one year at Mt. Fugen, an active volcano in Shimabara City of Nagasaki Prefecture, which is known for the disaster

M. Minamoto; Katsuya Matsunaga

1998-01-01

144

Challenging Gifted Learners through Children's Literature.  

ERIC Educational Resources Information Center

Gifted learners can be challenged by extending and enriching the mandated curriculum through the use of children's literature. Demonstrated is the use of the book "Mike Mulligan and His Steam Shovel" as a mechanism for learning about authorship, research skills, story evaluation, simple machines, problem solving, and technological change. (PB)

Bryant, Margaret A.

1989-01-01

145

How Children Respond to Art.  

ERIC Educational Resources Information Center

This essay discusses 13 pictorial devices with which one must be familiar to understand the illustrations in Virginia Lee Burton's "Mike Mulligan and His Steam Shovel." Color constancy, implied background, sharply drawn lines, abstractions of caricature, use of perspective, face on objects, and picture book narration are noted. (EJS)

Nodelman, Perry

1984-01-01

146

LABORATORY STUDY OF UNDRAINED SHEAR STRENGTHS BETWEEN UNDISTURBED AND REMOLDED SAMPLES  

Microsoft Academic Search

Soil samples are taken using a variety of samplers, some provide only disturbed samples, while others can provide relatively undisturbed samples. Samples can be obtained by digging out soil from the site using shovel or Split- spoon or SPT Sampler, samples taken this way are considered disturbed. Other type of samplers is using Piston samplers. Soil sampled in this manner

Norshakila Muhamad Rawai; Hisham Mohamad

147

Big Jobs: Planning for Competence  

ERIC Educational Resources Information Center

Three- to five-year-olds grow emotionally participating in meaningful and challenging physical, social, and problem-solving activities outdoors in an early childhood program on a farm. Caring for animals, planting, raking, shoveling, and engaging in meaningful indoor activities, under adult supervision, children learn to work collaboratively,…

Jones, Nancy P.

2005-01-01

148

HUNTER 10, TRUFLO GONDOLA WEIGHTS AND JACKET. PIVOTING ARMS RAISE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HUNTER 10, TRUFLO GONDOLA WEIGHTS AND JACKET. PIVOTING ARMS RAISE THE JACKET AND WEIGHTS. A PNEUMATIC SHOVEL PUSHES THE MORE RECENTLY POURED MOLD INTO THE COOLED MOLD, FORCING THE LATTER ONTO THE VIBRATING SHAKEOUT CONVEYOR AND LEAVING A SPACE UNDER THE RAISED JACKET AND WEIGHTS FOR A FRESHLY MADE UNPOURED MOLD. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

149

Characteristics of dental morphology in the Xinjiang Uyghurs and correlation with the EDARV370A variant.  

PubMed

Teeth are one of the most important materials for anthropological studies because they are likely to be preserved in ancient remains. While the frequencies of dental characteristics can provide clues to the phylogeny of populations, genetic studies at the individual level can further reveal the biological mechanisms and evolutionary context of dental characteristics. In this study, by analyzing 38 dental characteristics of 242 Xinjiang Uyghur individuals, we found that (i) the dental characteristics of the Uyghurs showed evidence of admixture between European and East Asian populations. The admixture proportions were in line with those previously reported in population genetic studies; (ii) the Xinjiang Uyghur dental characteristics formed three clusters in pairwise correlation analysis. One of the main clusters consisted of characteristics including incisor shoveling, double shoveling and mesial ridge; and (iii) all the characteristics in this cluster were significantly correlated with the genetic variant EDARV370A. The extracted composite phenotypic factor was also significantly associated with EDARV370A, which explained 18% of the total phenotypic variance. This indicated a pleiotropic effect, i.e., the same genetic factor affects a number of dental characteristics at the same time. Our results confirmed that EDARV370A, a genetic variant that first originated in East Asia about 30000 years ago, played an important role in incisor shoveling in East Asia. This finding suggested that incisor shoveling in modern humans in East Asia is likely to have appeared after the late Pleistocene. PMID:24752358

Tan, JingZe; Peng, QianQian; Li, JinXi; Guan, YaQun; Zhang, LiPing; Jiao, Yi; Yang, YaJun; Wang, SiJia; Jin, Li

2014-05-01

150

17. Photocopied August 1978. CANAL SECTION II, NEAR ASHMUN STREET, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. Photocopied August 1978. CANAL SECTION II, NEAR ASHMUN STREET, LOOKING WEST, DECEMBER 7, 1900. ONE OF THE CITY'S NEW BRIDGES OVER THE CANAL IS IN THE BACKGROUND. TEMPORARY DUMP TRACKS, DUMP TRAINS AND DUMP TRAIN LOCOMOTIVES, AND STEAM SHOVELS ARE ALL SHOWN IN OPERATION. (106) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

151

16. Photocopied August 1978. CANAL SECTION I, LOOKING EAST, AUGUST ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. Photocopied August 1978. CANAL SECTION I, LOOKING EAST, AUGUST 21, 1900. NOTE THE DUMP TRAIN ENGINES PUSHING THE TRAIN OF DUMP CARS AWAY FROM THE STEAM SHOVEL. (62) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

152

Diesel Engine Technician  

ERIC Educational Resources Information Center

Diesel engine technicians maintain and repair the engines that power transportation equipment such as heavy trucks, trains, buses, and locomotives. Some technicians work mainly on farm machines, ships, compressors, and pumps. Others work mostly on construction equipment such as cranes, power shovels, bulldozers, and paving machines. This article…

Tech Directions, 2010

2010-01-01

153

VIEW LOOKING NORTHEAST SHOWING THE TRASH GRATE THAT REPLACED THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW LOOKING NORTHEAST SHOWING THE TRASH GRATE THAT REPLACED THE LOCK GATES TO LOCK 71 WHEN THE FLIGHT OF FIVE WAS CONVERTED TO A SPILLWAY AFTER THE LARGER LOCKS, 34 AND 35, WERE PUT INTO OPERATION. THE SHOVEL TRUCK IN THE VIEW IS USED TO CLEAR DEBRIS. - New York State Barge Canal, Lockport Locks, Richmond Avenue, Lockport, Niagara County, NY

154

SOME BOARD OF LONGITUDE INSTRUMENTS IN THE NINETEENTH CENTURY  

Microsoft Academic Search

A series of calamitous British disasters at sea occurred at the turn of the 17th century, many of which can be attributed to poor navigation compounded by inability to find longitude. Perhaps the most momentous was that of Sir Cloudsley Shovel's returning Mediterranean Squadron which was comprehensively wrecked on the Scilly Islands in 1707 with the loss of four large

A. N. STIMSON

155

15. Photocopied August 1978. LOCOMOTIVE CRANE IN THE ROCK CUT, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. Photocopied August 1978. LOCOMOTIVE CRANE IN THE ROCK CUT, AUGUST 21, 1900. LOADING DUMP CARS. A STEAM SHOVEL LOADING DUMP CARS IS VISIBLE IN THE LEFT BACKGROUND. (61) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

156

Cultural Resources Survey and Testing for Davis Pond Freshwater Diversion, St. Charles Parish, Louisiana. Volume 1.  

National Technical Information Service (NTIS)

A cultural resources survey was conducted within the Davis Pond project area, St. Charles Parish, LA. The work included an intensive pedestrian survey with 20 m lane spacing within all of the construction corridor that was not inundated. Shovel tests were...

K. R. Jones H. A. Franks T. R. Kidder

1994-01-01

157

56. Photographic copy of historic photo, 1911 (original print filed ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

56. Photographic copy of historic photo, 1911 (original print filed in Record Group 115, National Archives, Washington, D.C.). STEAM SHOVEL EXCAVATING GRAVEL FOR FACING LOWER DEER FLAT EMBANKMENT. - Boise Project, Deer Flat Embankments, Lake Lowell, Nampa, Canyon County, ID

158

Interactions between Energy Efficiency Programs funded under the Recovery Act and Utility Customer-Funded Energy Efficiency Programs  

Microsoft Academic Search

Since the spring of 2009, billions of federal dollars have been allocated to state and local governments as grants for energy efficiency and renewable energy projects and programs. The scale of this American Reinvestment and Recovery Act (ARRA) funding, focused on 'shovel-ready' projects to create and retain jobs, is unprecedented. Thousands of newly funded players - cities, counties, states, and

Charles A. Goldman; Elizabeth Stuart; Ian Hoffman; Merrian C. Fuller; Megan A. Billingsley

2011-01-01

159

Isolation of Phyllosilicate-Iron Redox Cycling Microorganisms from an Illite-Smectite Rich Hydromorphic Soil  

PubMed Central

The biogeochemistry of phyllosilicate–Fe redox cycling was studied in a Phalaris arundinacea (reed canary grass) dominated redoximorphic soil from Shovelers Sink, a small glacial depression near Madison, WI. The clay size fraction of Shovelers Sink soil accounts for 16% of the dry weight of the soil, yet contributes 74% of total Fe. The dominant mineral in the clay size fraction is mixed layer illite–smectite, and in contrast to many other soils and sediments, Fe(III) oxides are present in low abundance. We examined the Fe biogeochemistry of Shovelers Sink soils, estimated the abundance of Fe redox cycling microorganisms, and isolated in pure culture representative phyllosilicate–Fe oxidizing and reducing organisms. The abundance of phyllosilicate–Fe reducing and oxidizing organisms was low compared to culturable aerobic heterotrophs. Both direct isolation and dilution-to-extinction approaches using structural Fe(II) in Bancroft biotite as a Fe(II) source, and O2 as the electron acceptor, resulted in recovery of common rhizosphere organisms including Bradyrhizobium spp. and strains of Cupriavidus necator and Ralstonia solanacearum. In addition to oxidizing biotite and soluble Fe(II) with O2, each of these isolates was able to oxidize Fe(II) in reduced NAu-2 smectite with NO3- as the electron acceptor. Oxidized NAu-2 smectite or amorphous Fe(III) oxide served as electron acceptors for enrichment and isolation of Fe(III)-reducing microorganisms, resulting in recovery of a strain related to Geobacter toluenoxydans. The ability of the recovered microorganisms to cycle phyllosilicate–Fe was verified in an experiment with native Shovelers Sink clay. This study confirms that Fe in the native Shovelers Sink clay is readily available for microbial redox transformation and can be cycled by the Fe(III)-reducing and Fe(II)-oxidizing microorganisms recovered from the soil.

Shelobolina, Evgenya; Konishi, Hiromi; Xu, Huifang; Benzine, Jason; Xiong, Mai Yia; Wu, Tao; Blothe, Marco; Roden, Eric

2012-01-01

160

Isolation of phyllosilicate-iron redox cycling microorganisms from an illite-smectite rich hydromorphic soil.  

PubMed

The biogeochemistry of phyllosilicate-Fe redox cycling was studied in a Phalaris arundinacea (reed canary grass) dominated redoximorphic soil from Shovelers Sink, a small glacial depression near Madison, WI. The clay size fraction of Shovelers Sink soil accounts for 16% of the dry weight of the soil, yet contributes 74% of total Fe. The dominant mineral in the clay size fraction is mixed layer illite-smectite, and in contrast to many other soils and sediments, Fe(III) oxides are present in low abundance. We examined the Fe biogeochemistry of Shovelers Sink soils, estimated the abundance of Fe redox cycling microorganisms, and isolated in pure culture representative phyllosilicate-Fe oxidizing and reducing organisms. The abundance of phyllosilicate-Fe reducing and oxidizing organisms was low compared to culturable aerobic heterotrophs. Both direct isolation and dilution-to-extinction approaches using structural Fe(II) in Bancroft biotite as a Fe(II) source, and O(2) as the electron acceptor, resulted in recovery of common rhizosphere organisms including Bradyrhizobium spp. and strains of Cupriavidus necator and Ralstonia solanacearum. In addition to oxidizing biotite and soluble Fe(II) with O(2), each of these isolates was able to oxidize Fe(II) in reduced NAu-2 smectite with [Formula: see text] as the electron acceptor. Oxidized NAu-2 smectite or amorphous Fe(III) oxide served as electron acceptors for enrichment and isolation of Fe(III)-reducing microorganisms, resulting in recovery of a strain related to Geobacter toluenoxydans. The ability of the recovered microorganisms to cycle phyllosilicate-Fe was verified in an experiment with native Shovelers Sink clay. This study confirms that Fe in the native Shovelers Sink clay is readily available for microbial redox transformation and can be cycled by the Fe(III)-reducing and Fe(II)-oxidizing microorganisms recovered from the soil. PMID:22493596

Shelobolina, Evgenya; Konishi, Hiromi; Xu, Huifang; Benzine, Jason; Xiong, Mai Yia; Wu, Tao; Blöthe, Marco; Roden, Eric

2012-01-01

161

Basic Hand Tools for Bricklaying and Cement Masonry [and] Basic Hand Tools of the Carpenter.  

ERIC Educational Resources Information Center

Intended for student use, this unit discusses and illustrates the tools used in brick and masonry and carpentry. Contents of the brick and masonry section include informative materials on bricklaying tools (brick trowels, joint tools, levels, squares, line and accessories, rules, hammers and chisels, tool kits) and cement masonry tools (tampers,…

Texas A and M Univ., College Station. Vocational Instructional Services.

162

Chamber Formation and Morphogenesis in the Developing Mammalian Heart  

Microsoft Academic Search

In this study we challenge the generally accepted view that cardiac chambers form from an array of segmental primordia arranged along the anteroposterior axis of the linear and looping heart tube. We traced the spatial pattern of expression of genes encoding atrial natriuretic factor, sarcoplasmic reticulum calcium ATPase, Chisel, Irx5, Irx4, myosin light chain 2v, and ?-myosin heavy chain and

Vincent M. Christoffels; Petra E. M. H. Habets; Diego Franco; Marina Campione; Frits de Jong; Wouter H. Lamers; Zheng-Zheng Bao; Steve Palmer; Christine Biben; Richard P. Harvey; Antoon F. M. Moorman

2000-01-01

163

Biomass Production, Nitrogen Accumulation and Yield in Wheat under Two Tillage Systems and Nitrogen Supply in the Argentine Rolling Pampa  

Microsoft Academic Search

Biomass production and partition, total nitrogen accumulation, grain yield and yield components in wheat were evaluated along two years. In 2000, two tillage systems were analyzed: mouldboard plough and chisel plough, for two cultivars: Buck Poncho and Buck Charrúa, under three fertilization treatments: I) without N, ii) 90 kg N ha? in a single dose at sowing and iii) 45

Silvina I. Golik; Hugo O. Chidichimo; Santiago J. Sarandón

164

Long-term tillage and maize monoculture effects on a tropical Alfisol in western Nigeria. I. Crop yield and soil physical properties  

Microsoft Academic Search

A wide range of tillage methods (e.g. mouldboard ploughing, discing, harrowing, chiselling, notill, ridge till, and their combinations) are used for continuous maize (Zea mays L.) cropping in western Nigeria without the benefits of experimental data on their comparative effects on soil properties and crop response. Therefore, the main objective of this experiment was to evaluate the impact of a

R. Lal

1997-01-01

165

Effect of reduced tillage systems on earthworm communities in a 6-year organic rotation  

Microsoft Academic Search

Chisel plough or no-till practises are clearly attributed to sustainable farming for the support of soil organisms and soil biological functioning. However, in organic farming these techniques are only applied to a very small extent since there is a need for cultivation to control weeds. In organic farming it is important to develop and establish less destructive soil tillage practises

Maren Metzke; Martin Potthoff; Michael Quintern; Jürgen Heß; Rainer Georg Joergensen

2007-01-01

166

An overview of the computer output microfilm field  

Microsoft Academic Search

From the earliest times, man has made his mark. At first his marks were made with his own fingers on walls of caves. He used a chisel or brush to create pictures of animals. He developed symbols, alphabet and languages. Man used marks to pass information from person to person and from generation to generation. Through the ages, man recorded

Don M. Avedon

1969-01-01

167

The Excavation Technology used in the Cow Catacombs of the Sacred Animal Necropolis, North Saqqara, Egypt  

Microsoft Academic Search

The technology used in tomb excavation in ancient Egypt has not been the subject of thorough investigation to date. A 'false end' in the catacombs of the mother of Apis bulls at the North Saqqara necropolis provides evidence of one excavation system used by tomb excavators. Chisel marks and 'cone' excavations elsewhere in the catacombs provide some evidence of an

Christopher J. Davey

168

TRUNK WOOD DISCOLORATION AND DECAY FOLLOWING ROOT WOUNDING  

Microsoft Academic Search

Discoloration and decay of trunk wood following root severance occurred only in trees that exhibited weak Wall 2 compartmentalization of chisel wounds made in the trunks. Furthermore, trunk wood discoloration only occurred when the root cambium died back to, or beyond, the junction of root and trunk. Thus, that trunk wood discoloration induced by root severance may have been the

Frank S. Santamour

169

Tillage System, Fertilizer Nitrogen Rate, and Timing Effect on Corn Yields in the Texas Blackland Prairie  

Microsoft Academic Search

most common tillage system used in this region for corn production has been a chisel tillage system. A manage- New N management and conservation tillage systems are needed ment system using raised wide beds has been proposed to improve agricultural sustainability on the Blackland Prairie of Texas. In 1994, an experiment was established to determine plant as a conservation tillage

H. Allen Torbert; Kenneth N. Potter; John E. Morrison

2001-01-01

170

I. Wheat seedling emergence under controlled climates  

Microsoft Academic Search

Experiments to determine the effects of the machinery and techniques used in creating direct-drilled seed grooves, and of covering the seeds, on wheat seed fate and soil physical characteristics are described. Comparisons were initially made in soils at either end of the available moisture range, and under contrasting controlled climatic conditions. Three coulter types were compared—an experimental chisel coulter, and

M. A. Choudhary; C. J. Baker

1980-01-01

171

An ultra-clean technique for accurately analysing Pb isotopes and heavy metals at high spatial resolution in ice cores with sub-pg g ?1 Pb concentrations  

Microsoft Academic Search

Measurements of Pb isotope ratios in ice containing sub-pgg?1 concentrations are easily compromised by contamination, particularly where limited sample is available. Improved techniques are essential if Antarctic ice cores are to be analysed with sufficient spatial resolution to reveal seasonal variations due to climate. This was achieved here by using stainless steel chisels and saws and strict protocols in an

Laurie J. Burn; Kevin J. R. Rosman; Jean-Pierre Candelone; Paul Vallelonga; Graeme R. Burton; Andrew M. Smith; Vin I. Morgan; Carlo Barbante; Sungmin Hong; Claude F. Boutron

2009-01-01

172

Formalizing Graphical Service Descriptions Using SDL  

Microsoft Academic Search

It is convenient to describe telecomms services using a graphical no- tation that is accessible to non-specialists. However, the notation should also have a formal interpretation for rigorous analysis. C RESS (Chisel Representation Em- ploying Systematic Specification) has been developed for this purpose. A brief overview of C RESS is given. It is explained how features (additional services) can be

Kenneth J. Turner

2003-01-01

173

Soil porosity characteristics and water movement under zero tillage in silty soils in Argentinian Pampas  

Microsoft Academic Search

The objective of this study was to identify pore characteristics (quantity, distribution, stability and orientation of pores) that condition water dynamics under continuous zero tillage (ZT) on silty soils of the Argentinian Rolling Pampas. Soil properties were analyzed under continuous chisel plough (CP) and ZT treatments from three trials with different duration and crop sequence. The following soil properties of

M. C. Sasal; A. E. Andriulo; M. A. Taboada

2006-01-01

174

Reduction Malarplasty without External Incision: A Simple Technique  

Microsoft Academic Search

Background: The concept of Eastern facial beauty is different from that of the Western. Prominent malar bones are perceived as unattractive by Easterners, including the Thai. Many techniques for malar reduction, such as chiseling or burring of the zygomatic body, are ineffective in reducing facial width. At present, the concept of medial movement of the zygomatic body is accepted as

Charan Mahatumarat; Nond Rojvachiranonda

2003-01-01

175

Cutting Tools, Files and Abrasives. Pre-Apprenticeship Phase 1 Training.  

ERIC Educational Resources Information Center

This self-paced student training module on cutting tools, files, and abrasives is one of a number of modules developed for Pre-apprenticeship Phase 1 Training. Purpose of the module is to enable students to identify and explain the proper use and care of various knives, saws, snips, chisels, and abrasives. The module may contain some or all of the…

Lane Community Coll., Eugene, OR.

176

Endoatmospheric Interceptor test capabilities in the NSWC Hypervelocity Tunnel 9  

NASA Astrophysics Data System (ADS)

The test capabilities of the Naval Surface Warfare Center (NWC) Hypervelocity Tunnel 9 are described. Aerooptical tests, shear layer radiation tests, generic forebody aerooptical tests, chisel forebody aerooptical tests, aerothermal tests, jet interaction and stability tests, and shroud separation tests are addressed. Future capability enhancements of the tunnel are briefly discussed.

Hedlund, Eric R.

1992-05-01

177

The first discovery of a brachiosaurid from the Asian continent  

NASA Astrophysics Data System (ADS)

Described here is a sauropod tooth from the Early Cretaceous of South Korea, similar to Brachiosaurus. The crown of the tooth is beveled off lingually so that when worn it presents a chisel-like edge. This find confirms the presence of a brachiosaurid in East Asia during the Early Cretaceous.

Lim, J.-D.; Martin, L. D.; Baek, K.-S.

2001-02-01

178

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

179

Bucyrus say HydraCrowd could generate revenue  

SciTech Connect

Amongst news of new products from US suppliers is the announcement by Bucyrus International of HydraCrowd which eliminates the need for rope crowd change intervals in electric shovels. Active Control Technology has had its Wi-Fi mesh network system for underground communications and tracking system approved by the MSHA. The Spatial Solutions Division of Leica Geosystems has gone into partnership with Maptek to supply laser scanners and associated mine scanning software. 2 photos.

NONE

2009-03-15

180

Anomalous morphologic formation of deciduous and permanent teeth in a 5-year-old 15th century child: a variant of the Ekman-Westborg-Julin syndrome.  

PubMed

A gross morphologic anomaly affecting both the primary and secondary teeth of unknown cause is presented. A 5-year-old American Indian child exhibited macrodontia, extreme shovel-shaping, agenesis, three-rooted deciduous molars, dens invaginatus, and other less striking dental features. This case represents the earliest example of a variant of the Ekman-Westborg-Julin syndrome reported in the New World. PMID:2196508

Mann, R W; Dahlberg, A A; Stewart, T D

1990-07-01

181

An oil sand pseudo-elastic model for determining ground deformation under large mobile mining equipment  

Microsoft Academic Search

Strain softening of oil sand under dynamic loading from large mining equipment inhibits the ability of the equipment to function\\u000a at optimal design performance. This paper looks at the findings of dynamic plate load tests, which effectively mimick the\\u000a loading and unloading action of a shovel track pad. A pseudo-elastic model was proposed based on the results of the dynamic

Ardeshir Dehmoobed Sharif-abadi; Tim Grain Joseph

2010-01-01

182

Wonder Underground  

NSDL National Science Digital Library

In this activity, learners engage in the joy of discovery as they dig to uncover the wonders that can be found underground. Learners use tools (gardening shovels and sifters) to find natural items like twigs and litter like bottle caps buried in topsoil. Learners use scientific skills to collect, classify, describe and record their findings. Use this activity to talk about the difference between non-living and living things and/or littering.

Museum, Chicago C.

2008-01-01

183

Frequency and variability of dental morphology in deciduous and permanent dentition of a Nasa indigenous group in the municipality of Morales, Cauca, Colombia  

PubMed Central

Objectives: To determine the frequency, variability, sexual dimorphism and bilateral symmetry of fourteen dental crown traits in the deciduous and permanent dentition of 60 dental models (35 women and 25 men) obtained from a native, indigenous group of Nasa school children of the Musse Ukue group in the municipality of Morales, Department of Cauca, Colombia. Methods: This is a quantitative, descriptive, cross-sectional study that characterizes dental morphology by means of the systems for temporary dentition from Dahlberg (winging), and ASUDAS (crowding, reduction of hypocone, metaconule and cusp 6), Hanihara (central and lateral incisors in shovel-shape and cusp 7), Sciulli (double bit, layered fold protostylid, cusp pattern and cusp number) and Grine (Carabelli trait); and in permanent dentition from ASUDAS (Winging, crowding, central and lateral incisors in shovel-shape and double shovel-shape, Carabelli trait, hypocone reduction, metaconule, cusp pattern, cusp number, layered fold protostylid, cusp 6 and cusp 7). Results: The most frequent dental crown features were the shovel-shaped form, grooved and fossa forms of the Carabelli trait, metaconule, cusp pattern Y6, layered fold, protostylid (point P) and cusp 6. Sexual dimorphism was not observed and there was bilateral symmetry in the expression of these features. Conclusions: The sample studied presented a great affinity with ethnic groups belonging to the Mongoloid Dental Complex due to the frequency (expression) and variability (gradation) of the tooth crown traits, upper incisors, the Carabelli trait, the protostylid, cusp 6 and cusp 7. The influence of the Caucasoide Dental Complex associated with ethno-historical processes cannot be ruled out.

Diaz, Eider; Garcia, Lorena; Hernandez, Michelle; Palacio, Lesly; Ruiz, Diana; Velandia, Nataly; Villavicencio, Judy

2014-01-01

184

Art Curriculum That Works. Art for Your Summer Vacation  

ERIC Educational Resources Information Center

Kids can pack their shovel and pail, slather on the sunscreen and get ready to create their best artwork yet this summer. Art can be the one activity that you can take to the beach, the lake and special faraway places this summer. Being an artist on your vacation is an added dimension to how you see and experience the world you visit during this…

Healy, John W.

2005-01-01

185

Temporal flexibility of reproduction in temperate-breeding dabbling ducks  

USGS Publications Warehouse

I compared nesting intervals during three consecutive years in five species of temperate-nesting dabbling ducks (Mallard [Anas platyrhynchos], Northern Pintail [Anas acuta], Northern Shoveler [Anas clypeata], Blue-winged Teal [Anas discors], Gadwall [Anas strepera]) and assessed whether differences existed in timing of refractoriness. Most nesting by females of all five species ended by the summer solstice. Nesting ended earliest for Northern Shovelers and Northern Pintails and latest for Gadwalls. Some Mallards, Blue-winged Teal, and Gadwalls continued to nest into mid- and late summer, whereas Northern Shovelers and Northern pintails did not. Mallards, Blue-winged Teal, and Gadwalls accounted for 99% (81 of 82) of flightless broods resulting from nests initiated during mid- or late summer in North Dakota and 98% (58 of 59) of flightless juveniles shot on or after 1 October by a random sample of duck hunters from across the United States. Early cessation of breeding by Northern Shovelers may have evolved in response to the species' limited flexibility in diet. Photorefractory mechanisms that limit most breeding to spring presumably evolved in response to severe constraints on reproductive success when nesting continued through summer(e.g. mortality of late-hatched young and molting females due to low temperatures). Interspecific differences in photosensitivity may account for variation in timing of cessation of nesting in late spring, but controlled experiments are needed to assess the possible role of non-photic influences. My results suggest that the refractory mechanisms controlling length of the breeding in temperate-nesting dabbling ducks are more varied and complex than previously thought, with non-photic influences (e.g. water conditions, food availability, food quality) having a larger role than indicated by earlier research.

Krapu, G. L.

2000-01-01

186

60. Photographic copy of historic photo, April 25, 1907 (original ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

60. Photographic copy of historic photo, April 25, 1907 (original print filed in Record Group 115, National Archives, Washington, D.C.). UPPER DEER FLAT EMBANKMENT. STEAM SHOVEL NO. 1 LOADING CARS IN EASTERLY BORROW PIT. CARS IN THIS TRAIN OF 12 NEARLY ALL LOADED. EAIGHT MINUTES REQUIRED TO LOAD 12 CARS EQUAL TO 42 CU YDS. PLACE MEASUREMENT. - Boise Project, Deer Flat Embankments, Lake Lowell, Nampa, Canyon County, ID

187

Age-specific survival and philopatry in three species of European ducks: a long-term study  

USGS Publications Warehouse

Capture-recapture and band recovery models were used to estimate age-specific survival probabilities for female Northern Shovelers (Anas clypeata), Common Pochards (Aythya ferina), and Tufted Ducks (Aythya.fuligula) at Engure Marsh, Latvia, in 1964-1993. We banded more than 65,100 day-old ducklings of both sexes and captured 10,211 incubating females (3,713 new bandings and 6,498 recaptures). We developed a set of 3-age capture-recapture models to estimate annual survival rates for female ducklings, yearlings (SY), and adults (ASY) using programs SURGE and SURVIV and selected parsimonious models using a method developed bv Akaike (1973). Survival rates of SY and ASY females were highest-for Tufted Ducks intermediate for Common Pochards, and lowest for Northern Shovelers. Survival rates of SY and ASY females varied in parallel for shovelers and pochards. We believe that much of the difference in survival estimates between SY and ASY birds was caused by mortality rather than permanent emigration. Estimates of day-old duckling survival, reflecting both mortality and permanent emigration, were 0.12 for shoveler, 0.06 for pochard, and 0.03 for Tufted Duck. For all species, duckling survival varied over years, but the pattern of variation was not similar to that of the other age classes. Estimates of survival using band recovery data for SY + ASY female pochards and Tufted Ducks were similar to the capture-recapturee stimates, suggestingt hat surviving females returned to the breeding marsh with probabilities approaching 1.

Blums, P.; Mednis, A.; Bauga, I.; Nichols, J.D.; Hines, J.E.

1996-01-01

188

59. Photographic copy of historic photo, April 25, 1907 (original ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

59. Photographic copy of historic photo, April 25, 1907 (original print filed in Record Group 115, National Archives, Washington, D.C.). UPPER DEER FLAT EMBANKMENT. STEAM SHOVEL NO. 1 AT WORK ON EASTERLY BORROW PIT. CLASS OF MATERIAL BEING EXCAVATED IS LARGELY SAND AND GRAVEL, WITH ENOUGH CLAY TO FORM A BOND BETWEEN SAND AND GRAVEL. - Boise Project, Deer Flat Embankments, Lake Lowell, Nampa, Canyon County, ID

189

62. Photographic copy of historic photo, April 25, 1907 (original ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

62. Photographic copy of historic photo, April 25, 1907 (original print filed in Record Group 115, National Archives, Washington, D.C.). UPPER DEER FLAT EMBANKMENT. VIEW FROM EASTERLY END OF EMBANKMENT UNDER CONSTRUCTION. TRAIN IN FOREGROUND RETURNING TO EASTERLY BORROW PIT. STEAM SHOVEL NO.2 IN DISTANCE AT WORK IN WESTERLY BORROW PIT. - Boise Project, Deer Flat Embankments, Lake Lowell, Nampa, Canyon County, ID

190

The Location of the Maximum Temperature on the Cutting Edges of a Drill  

SciTech Connect

This study analyzes the temperature profile along the cutting edges of a drill and describes how the temperature on the chisel edge can exceed the temperature on the primary cutting edges. A finite element model predicts the temperature distribution in the drill, where the heat flux loads applied to the finite element model are determined from analytical equations. The model for the heat flux loads considers both the heat generated on the shear plane and the heat generated on the rake face of the tool to determine the amount of heat flowing into the tool on each segment of the cutting edges. Contrary to the conventional belief that the maximum temperature occurs near the outer corner of the drill, the model predicts that the maximum temperature occurs on the chisel edge, which is consistent with experimental measurements of the temperature profile.

Bono, M J; Ni, J

2005-01-07

191

Characteristics of Band-to-Band Tunneling Hot Hole Injection for Erasing Operation in Charge-Trapping Memory  

NASA Astrophysics Data System (ADS)

In this paper, we present a combined charge-pumping measurement method for charge distribution profiling in charge-trapping memory. Electron and hole distributions after channel hot electron (CHE) or channel-initialed secondary electron (CHISEL) programming and band-to-band tunneling hot hole (BBHH) erasing are accurately determined. It is shown that BBHH-induced hot holes distribute in a narrow region near the drain junction, and cannot neutralize all the electrons particularly in CHISEL-programmed devices. The influence of the BBHH erasing condition on the width of hole distribution is demonstrated, and the effects on the characteristics of erasing speed and P/E cycling endurance are investigated and analyzed. It is shown that in the CHE-programmed devices, the erasing speed can be enhanced and endurance characteristics can be improved if a high drain voltage is used during erasing operation.

Sun, Lei; Pan, Liyang; Pang, Huiqing; Zeng, Ying; Zhang, Zhaojian; Chen, John; Zhu, Jun

2006-04-01

192

Distribution and Impact of Local Trapped Charges in Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) Memory  

NASA Astrophysics Data System (ADS)

In this paper we propose a two-transistor model with an RPT for the punch-through resistor in the silicon-oxide-nitride-oxide-silicon (SONOS) memory cell. With this model, the subthreshold leakage current induced by the local trapped charges in silicon nitride and the impact on the cell's read characteristics are studied. Some solutions to decrease this leakage current and change the distribution of the trapped charges are proposed and analyzed, including programming condition optimization, the channel initiated secondary electron (CHISEL) programming, and cell structure optimization. Moreover, using the CHISEL or channel hot electron (CHE) programming, the influences on the programming and the erase characteristics of different charge distributions are investigated.

Sun, Lei; Pan, Liyang; Zeng, Ying; Pang, Huiqing; Wang, Jimin; Zhang, Zhaojian; Li, Xiyou; Zhu, Jun

2005-04-01

193

EFFECTS OF CULTURAL MANAGEMENT ON THE FOOT AND ROOT DISEASE COMPLEX OF DURUM WHEAT  

Microsoft Academic Search

SUMMARY The effects of three tillage techniques (minimum tillage (chisel ploughing), and mouldboard ploughing to a depth of 25 and 50 cm) and four 2-year crop rota- tions (continuous wheat, wheat\\/barley, wheat\\/sugar- beet and wheat\\/fallow) on the foot and root disease complex of durum wheat were studied from 1999 to 2001 in an experimental field at the Bologna University farm.

M. Montanari; G. Innocenti; G. Toderi

2006-01-01

194

Influence of the ploughing effect on the dynamic behaviour of the self-vibratory drilling head  

Microsoft Academic Search

The vibratory drilling process enables the chip to be split into small elements thanks to axial vibrations of the drill self-maintained by the cutting energy. The vibrations should remain stable when machining, and damping be removed or very limited—particularly the ploughing force induced by the chisel edge and the flank face. To predict the behaviour of the self-vibratory drilling head,

D. Brissaud; A. Gouskov; N. Guibert; J. Rech

2008-01-01

195

USE HYDRODYNAMIC CAVITATION FOR INCREASE OF EFFICIENCY OF PROCESS OF WELL DRILLING  

Microsoft Academic Search

For the first time it is offered to transform a stationary flow washover fluid to a high-frequency pulsing flow at the expense of realization of a mode the periodically-stalled hydrodynamic cavitation in a flowing part of a chisel string to superimpose axial vibrational accelerations on a rock-cutting tool in rotary drilling the boreholes in hard and superhard rocks. The circuit

Ivan K. Manko; Viktor V. Pilipenko; Leonid G. Zapols

196

Scanning Probe Direct-Write of Germanium Nanostructures  

SciTech Connect

Bottom-up nanostructure synthesis has played a pivotal role in the advancement of nanoscale science. This approach is typically less labor and energy intensive than its topdown counterpart because only the required amount of material is grown from a chosen precursor, rather than a macroscopic object being chiseled down to the desired size. However, device integration often requires complex manipulation steps for placing the synthesized nano-object in the appropriate location.

Torrey, Jessica D.; Vasko, Stephanie E.; Kapetanovic, Adnan; Zhu, Zihua; Scholl, Andreas; Rolandi, Marco

2010-09-24

197

Paint Scaler. Innovative Technology Summary Report  

SciTech Connect

The Paint Scaler can collect paint samples quickly and efficiently for lab analysis. The Rotary Hammer Drill is a 24-V battery operated, 3/4-in. rotary hammer drill. When used with an optional chipping adapter, the Bosch Rotary Hammer Drill can be used to perform chipping and chiseling tasks such as paint removal from either concrete or metal surfaces. It is ultra-compact, lightweight with an ergonomic balanced grip. The battery operation gives the operator more flexibility during sampling activities.

None

2000-06-01

198

Glossary of Construction Terms  

NSDL National Science Digital Library

Need to know what a cantilever is? Curious about screeding and Type II Moderate cement or cape chisels? Look no further than the Glossary of Construction Terms, provided by the National/California Contractor Referral and License Bureau. While by no means a definitive collection of construction terms, the glossary is fairly comprehensive in terms of the basics, offering short, clear explanations of tools, materials, and concepts. Topics include Carpentry, Concrete, Electrical, Heating and Air Conditioning, Painting, Plumbing, and Roofing, among others.

1999-01-01

199

Fallowing practices, soil water storage, plant- available soil nitrogen accumulation and wheat performance in South West Queensland  

Microsoft Academic Search

Radford, B.J., Gibson, G., Nielsen, R.G.H., Butler, D.G., Smith, G.D. and Orange, D.N., 1992. Fal- lowing practices, soil water storage, plant-available soil nitrogen accumulation and wheat perform- ance in South West Queensland. Soil Tillage Res., 22: 73-93. The effects of tillage frequency (conventional, reduced and zero), primary tillage implement (disc, blade and chisel plough), stubble management (retention and removal), gypsum

B. J. Radford; G. Gibson; R. G. H. Nielsen; D. G. Butler; G. D. Smith; D. N. Orange

200

Analysis of diatomite sediments from a paleolake in central Mexico using PIXE, X-ray tomography and X-ray diffraction  

Microsoft Academic Search

Diatomite samples from paleolake Tlaxcala, in Central Mexico, have been analyzed using proton induced X-ray emission (PIXE), X-ray tomography and X-ray diffraction. Chiseled blocks were scanned with a 0.7 MeV proton beam, 0.1 mm in diameter, in 0.25 mm steps across the sediments. X-ray tomography with the same step sizes was then applied, in order to compare the concentrations obtained

J. Miranda; A. Oliver; G. Vilaclara; R. Rico-Montiel; V. M. Macías; J. L. Ruvalcaba; M. A. Zenteno

1994-01-01

201

The Small Muscle-Specific Protein Csl Modifies Cell Shape and Promotes Myocyte Fusion in an Insulin-like Growth Factor 1Dependent Manner  

Microsoft Academic Search

We have isolated a murine cDNA encoding a 9-kD protein, Chisel (Csl), in a screen for transcrip- tional targets of the cardiac homeodomain factor Nkx2- 5. Csl transcripts were detected in atria and ventricles of the heart and in all skeletal muscles and smooth muscles of the stomach and pulmonary veins. Csl protein was distributed throughout the cytoplasm in fetal

Steve Palmer; Nicola Groves; Aaron Schindeler; Thomas Yeoh; Christine Biben; Cheng-Chun Wang; Duncan B. Sparrow; Louise Barnett; Nancy A. Jenkins; Neal G. Copeland; Frank Koentgen; Tim Mohun; Richard P. Harvey

2001-01-01

202

Influence of residual stresses on high cycle fatigue strength of Ti–6Al–4V subjected to foreign object damage  

Microsoft Academic Search

The role of residual stresses in the high cycle fatigue (HCF) strength of Ti–6Al–4V subjected to foreign object damage (FOD) was evaluated on simulated airfoil and rectangular geometries. Both real and simulated impacts were conducted using spherical projectiles launched at 300 m\\/s and quasi-static chisel indentation, respectively. The spheres used were 1 mm diameter glass beads while the quasi-static indentor

Steven R. Thompson; John J. Ruschau; Theodore Nicholas

2001-01-01

203

Brazing Alloys Indicate Turbomachinery Temperatures  

NASA Technical Reports Server (NTRS)

Foils serve as consumable thermometers. Stainless-steel tab with circular window holds brazing-foil sample in place. Tab tacked to object to be tested with capacitive-discharge spot welder operating in range 10 + 1 joules. After measurements, tabs and samples chiseled off, leaving tested object fairly well intact. Technique used on objects made of alloys with iron, nickel, or cobalt as principal ingredients.

Schlaff, J. W.

1985-01-01

204

Sugar cane management with humic extract and organic and mineral fertilizer: impacts on Oxisol some physical properties  

NASA Astrophysics Data System (ADS)

The present investigation has as objective to study the impact of cultive systems, humic extract and organic and mineral fertilizers on Oxisol some physical properties cultivated of sugar cane. It was developed in Aparecida do Taboado, Mato Grosso do Sul, Brazil, in Manufactores Alcoolvale. The study was in sugar cane culture implanted on 3th and 4th cycle. The experimental design was at randomized blocks following scheme in zone with eight treatments and four replications. The two treatments in main zone were represented by cultivation systems (with and without chisel) and the subzone fertilization (T1-mineral, T2-mineral+sugar cane residue, T3-mineral+humic and fulvic acids and T4-mix of mineral, sugar cane residue and humic and fulvic acids). In three soil layers: 0.00-0.05; 0.10-0.20 and 0.20-0.40 m were studied the physical soil properties: macroporosity, microporosity, total porosity and soil bulk density. Also evaluate the technological quality of sugar cane. The conclusions are: the application of mineral fertilizer+sugar cane residue+humic extract (Humitec ®) and cropping system with chisel were more effective in improving soil physical; the system of crop of sugar cane ratton implanted in the 2th and 3th cycle, without the use of chisel was better in the recovery of soil physical properties; the crop system without the chisel and the combination of mineral fertilizer+sugar cane residue was promising to increase of Brix, Pol juice, Pol sugar cane and total recoverable sugars Pol.

Alves, M. C.; Campos, F. S.; Souza, Z. M.

2012-04-01

205

Mold filling of semisolid metal slurries  

NASA Astrophysics Data System (ADS)

A constitutive model is developed experimentally for Al-7 % Si-0.6 % Mg alloy slurry. This equation has two parts to represent flow and structure evolution. The model is then used to simulate filling of a chisel-shaped mold of cylindrical cross section. Transport equations are solved for the flow variables, and the free surface is modeled by solving the conservation equation for a scalar “fluid-marker” variable, which is used to update the fluid properties, including density and viscosity.

Ilegbusi, O. J.; Brown, S.

1995-08-01

206

REACTIONS OF FUEL NITROGEN COMPOUNDS UNDER CONDITIONS OF INERT PYROLYSIS  

EPA Science Inventory

The paper describes the pyrolysis of fossil fuels and model nitrogen compounds in helium in a small quartz plow reactor, as part of a study of the chemical mechanisms involved in the conversion of fuel-nitrogen compounds to nitric oxide (NO) during combustion. Hydrogen cyanide (H...

207

Durability of Drainage Improvement by Combination of Main Drain and Trench Drains with Vertical Drains in Clayey Field Converted from Paddy to Upland Use  

NASA Astrophysics Data System (ADS)

The drainage efficiency of a subsurface drainage system for avoidance of standing water on the plow pan of clayey field was evaluated. A subsurface drainage system with a main drain and orthogonally adjoined rice husk trench drains joined by vertical rice husk drains was constructed on a test plot and compared to an identical control plot of paddy field converted to upland use under soybean cultivation. The ratio of total underdrain discharge to rainfall in the improved plot greatly increased over two years compared to that in a control plot. In the improved plot, the peak underdrain discharge per hour associated with some heavy rainfalls was around 3 mm/h in the first year but decreased to about 2 mm/h in the second year. By improving drainage in the paddy field, standing water on the plow pan was quickly eliminated after rain events and the period of flooding on the plow pan during the soybean growing season was greatly reduced. However, underdrain discharge in the improved plot decreased greatly in the third year to be at the same level as in the control plot, and rain water flooded the plow pan for extended periods of time.

Adachi, Kazuhide; Ohno, Satoshi; Furuhata, Masami; Ogura, Chikara; Tanimoto, Takeshi

208

A Near-Infrared Shock Wave in the 2006 Outburst of Recurrent Nova RS Ophiuchi  

Microsoft Academic Search

Near-infrared spectra are presented for the recent 2006 outburst of the recurrent nova RS Ophiuchi.We report the rare detection of an infrared shock wave as the nova ejecta plows into the preexisting wind of the secondary in the RS Oph system consisting of a white dwarf (WD) primary and a red giant secondary. The evolution of the shock is traced

Ramkrishna Das; Dipankar P. K. Banerjee; Nagarhalli M. Ashok

2006-01-01

209

Effects of residual biomass burning on the methane emission from a paddy field  

NASA Astrophysics Data System (ADS)

Methane (CH4) is generated by organic matter decomposition in anaerobic soil. It is said that about 20% of CH4 sources is paddy fields. At some paddy fields, residual biomass left after the harvest is burned and plowed into soil. And at the other fields, unburned residue is directly plowed. It is an unsolved problem what impact is brought on CH4 budget during following cultivated period by the difference in the plowed biomass amount in soil after the harvest. In this study, an experimental paddy field was divided into two areas. At one area biomass residue is burned and at the other area residue is directly plowed. On that basis, long-term continuous measurements of micrometeorological CH4 flux were conducted in both areas. Experimental site is located reclaimed land in the southern part of Okayama Prefecture, Japan. Single rice cropping cultivation has continued in a similar way every year. Intermittent irrigation water managements, or 3-days flooded and 4-days drained conditions, were carried out during almost all the period of rice cultivated term. CH4 flux was calculated by aerodynamic gradient technique. The open biomass burning experiment was conducted at one area in November 29, 2011. We illustrate some results for the control term before the burning experiment, and for the comparison term after the experiment.

Kunishio, A.; Akaike, Y.; Kawamoto, Y.; Murakami, H.; Ono, K.; Iwata, T.

2012-12-01

210

Folksong in the Classroom. Volume VI. 1985-86.  

ERIC Educational Resources Information Center

As this nation's settlers and immigrants built homes, railroads, and plowed the fields, they told their story through songs and ballads. Transmitting this cultural heritage is the goal of this volume containing songs, bibliographies, teaching ideas, and record and book reviews. These three issues focus on the songs of the railroads, the farmers,…

Scott, John A., Ed.; Seidman, Laurence I., Ed.

1986-01-01

211

America's First Government Documentary Films as Teaching Tools.  

ERIC Educational Resources Information Center

Reviews two documentaries produced by the U.S. government: "The Plow That Broke the Plains" (1936) and "The River" (1937). The first examines soil erosion in the Great Plains; the second considers Mississippi River usage. Narrates storylines and explains initial film criticism. Highlights the films' effectiveness for teaching about the New Deal…

Hendrickson, Kenneth E.

1991-01-01

212

Effects of tillage and winter cover cropping on microbial substrate-induced respiration and soil aggregation in two Japanese fields  

Microsoft Academic Search

We hypothesized that cover cropping could increase soil microbial activities under various tillage systems and that increased microbial activities would improve soil properties. Soil sampling was conducted at two fields in Japan in 2009. At the Ibaraki field (Andosol, clay loam), three tillage practices (no-tillage, plowing to 30?cm, and rotary tillage to 15?cm) and three types of winter cover cropping

Tomomi Nakamoto; Masakazu Komatsuzaki; Toshiyuki Hirata; Hajime Araki

2012-01-01

213

Soil physical responses to cattle grazing cover crops under conventional and no tillage in the Southern Piedmont USA  

Microsoft Academic Search

Grazing of cover crops in grain cropping systems can increase economic return and diversify agricultural production systems, but the environmental consequences of this intensified management have not been well documented, especially under different tillage systems. We conducted a multiple-year investigation of how cover crop management (grazed and ungrazed) and tillage system [conventional (CT; initial moldboard plowing and thereafter disk tillage)

Alan J. Franzluebbers; John A. Stuedemann

2008-01-01

214

Optimization of Hanyang University Plasma Focus Device as a Neutron Source  

Microsoft Academic Search

The optimum focusing conditions of the Hanyang University Plasma Focus (HUPF) device have been obtained by determining maximum power input to the focusing plasma while changing pressure at one fixed electrode, which leads to the maximum neutron generation. Six electrodes of different lengths have been used according to the snow-plow model to determine the conditions for the maximum neutron production

Hyun-Jong Woo; Kyu-Sun Chung; Yong-Sup Choi; Chi Young Han; Yong Ho Jung; Jong Kyung Kim; Jai-Ki Lee; Myoung-Jae Lee; Jooho Whang; Hyun-Jong You

2004-01-01

215

Changing Agricultural Education to Meet Needs of Emerging Careers  

ERIC Educational Resources Information Center

With less than 2% of Americans involved in traditional production agriculture (cows, plows, and sows), agricultural programs at the secondary and postsecondary levels must change to address the workforce of the future. AgrowKnowledge works at the national level to provide tools for changing agriculture, food, and natural resource educational…

Parker, Rick; Brase, Terry; Dewsnup, Mel; Anderson, Mandi; Collins, Ashley; Klopp, Deborah; Johnson, Brian; Feldmann, Holly

2009-01-01

216

Walking mechanism and simulation of cattle-like robot on soft ground  

Microsoft Academic Search

The walking procedure of the cattle, Bostaurus, on a paddy field before spring plowing was captured with a high-speed video camera. The properties of the paddy soil used for tests and the geometrical configurations of the hooves of the cattle were examined. The geometrical configurations and motion postures of the cattle during walking on paddy field were analyzed, and the

Chen Yong

2010-01-01

217

Stress-field Translation in the Healthy Human Temporomandibular Joint  

Microsoft Academic Search

Movement over the surface of the temporomandibular joint (TMJ) disc produces tractional forces. These forces potentially increase the magnitude of shear stresses and contribute to wear and fatigue of the disc. Theoretically, tractional forces in all synovial joints are the result of frictional forces, due to rubbing of the cartilage surfaces, and plowing forces, due to translation of the stress-field

L. M. Gallo; J. C. Nickel; L. R. Iwasaki; S. Palla

2000-01-01

218

26. Photo copy of photograph, (original in Forest Service Office, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. Photo copy of photograph, (original in Forest Service Office, Elkins, WV), photographer unknown, ca. 1936. VIEW NORTHWEST, GARAGE (DEMOLISHED), NURSERY MANAGER'S GARAGE AND RESIDENCE, AND PACKING BUILDING, TRANSPLANT SHEDS AND PLOW IN FOREGROUND. - Parsons Nursery, South side of U.S. Route 219, Parsons, Tucker County, WV

219

Earthworm numbers, distribution, and sampling under conservation tillage  

Microsoft Academic Search

In order for crops to grow, the soil must be porous enough for root penetration and water and gas flow to occur. Conservation tillage involves less mechanical loosening and mixing of soil than plowing, and so depends more on earthworms to do these tasks. Tillage, crop rotation, and chemical application affect earthworms. The effect of a chemical depends on its

John Berendsen Dickey

1990-01-01

220

Correcting soil acidification in continuous corn (zea mays L.): N rate, tillage and time  

Microsoft Academic Search

Use of ammoniacal N in continuous corn production results in greater acidification of the surface soil layer under conservation tillage. Moldboard plowing results in dilution of acid inputs to greater depth. The objective of this work was to observe soil reaction after a lime application made to a continuous corn experiment initiated in 1970. Four fertilizer N rates (0. 84.

J. H. Grove; R. L. Blevins

1988-01-01

221

ARSENIC TRANSPORT ACROSS THE GROUNDWATER ? SURFACE WATER INTERFACE AT A SITE IN CENTRAL MASSACHUSETTS  

EPA Science Inventory

Plow Shop Pond, located in central Massachusetts within the New England ?arsenic belt,? receives water from a series of interconnected upstream ponds as well as from upward-discharging groundwater. A small, shallow embayment on the southwest side of the pond is known as Red Cove...

222

33 CFR 323.4 - Discharges not requiring permits.  

Code of Federal Regulations, 2010 CFR

...fallow as part of a conventional rotational cycle are part of an established operation...not include the redistribution of soil, rock, sand, or other surficial materials...fill in wetland areas is not plowing. Rock crushing activities which result in...

2010-07-01

223

40 CFR 232.3 - Activities not requiring permits.  

Code of Federal Regulations, 2010 CFR

...fallow as part of a conventional rotational cycle are part of an established operation...not include the redistribution of soil, rock, sand, or other surficial materials in...fill in wetland areas is not plowing. Rock crushing activities which result in...

2010-07-01

224

33 CFR 323.4 - Discharges not requiring permits.  

Code of Federal Regulations, 2012 CFR

...fallow as part of a conventional rotational cycle are part of an established operation...not include the redistribution of soil, rock, sand, or other surficial materials...fill in wetland areas is not plowing. Rock crushing activities which result in...

2012-07-01

225

40 CFR 232.3 - Activities not requiring permits.  

Code of Federal Regulations, 2012 CFR

...fallow as part of a conventional rotational cycle are part of an established operation...not include the redistribution of soil, rock, sand, or other surficial materials in...fill in wetland areas is not plowing. Rock crushing activities which result in...

2012-07-01

226

40 CFR 232.3 - Activities not requiring permits.  

Code of Federal Regulations, 2011 CFR

...fallow as part of a conventional rotational cycle are part of an established operation...not include the redistribution of soil, rock, sand, or other surficial materials in...fill in wetland areas is not plowing. Rock crushing activities which result in...

2011-07-01

227

33 CFR 323.4 - Discharges not requiring permits.  

Code of Federal Regulations, 2011 CFR

...fallow as part of a conventional rotational cycle are part of an established operation...not include the redistribution of soil, rock, sand, or other surficial materials...fill in wetland areas is not plowing. Rock crushing activities which result in...

2011-07-01

228

Tests validate fiberglass cement to protect subsea FBE coating  

SciTech Connect

Rock-shield coating on subsea pipelines is a viable alternative to concrete coating when protection against rock dumping is required. Tests and installation experience indicates this use, providing that special attention is paid to the priming process, cleanliness of the coating applicator, handling of the line pipe, and selection of a suitable plow for trenching.

Traulsen, C.; Nielsen, N.J.R.; Nielsen, T.S. (Maersk Oil and Gas AS, Copenhagen (DK))

1990-09-17

229

Ten-Year Growth of Planted Paper Birch in Old Fields in Maine.  

National Technical Information Service (NTIS)

The survival and growth of paper birch seedlings planted in old fields were better where the sod was removed before planting than where the sod was left intact. Plowing a double furrow and planting on the second overturned slice gave the best results. Ini...

J. C. Bjorkbom

1972-01-01

230

Retirement Straight Talk: The Self-Discovery that It's Not a Simple Transition but a New Phase in Life  

ERIC Educational Resources Information Center

After 38 years as a teacher and school administrator, including 24 years as the superintendent in Minnetonka, Minnesota, Donald Draayer, the author of this article, has discovered that retirement is not one transition, but many, affecting all aspects of life. He is finding that retirement is like virgin soil. The ground must be cleared, plowed and…

Draayer, Donald R.

2004-01-01

231

The Effects of Soil Carbon on Phosphorus and Sediment Loss from Soil Trays by Overland Flow  

Microsoft Academic Search

was closely correlated with hot water-extractable carbo- hydrate and not total C. Soil chemical constituents influence soil structure and erosion po- When a soil is plowed and exposed to the air, changes tential. We investigated manure and inorganic fertilizer applications on soil chemistry (carbon (C) quality and exchangeable cations), ag- in organic matter quality are also accompanied with a gregation,

R. W. McDowell; A. N. Sharpley

2003-01-01

232

Devens 2008 Monitoring Update  

EPA Science Inventory

This document presents results from site monitoring activities during calendar year 2008 at the EPA/ORD Red Cove Study Area relative to site characterization activities under Operable Units 01 (Shepley's Hill Landfill) and 11 (Plow Shop Pond) at the Fort Devens Superfund site. T...

233

The Navajo Agricultural Projects Industry: Subsistence Farming to Corporate Agribusiness.  

ERIC Educational Resources Information Center

Originally designed to create small farms for individual Navajos, the irrigation project has grown into a single 110,000-acre corporate agribusiness, the land's management has fallen out of the grasp of individual Navajos, and the idea of subsistence farming has been plowed under for the planting of major money-making crops. (NQ)

Barry, Tom

1979-01-01

234

Sustainability of agroecosystems in semi-arid grasslands: simulated management of woody vegetation in the Rio Grande Plains of southern Texas and northeastern Mexico  

Microsoft Academic Search

We describe a model that simulates use of chemical treatments, mechanical treatments (roller chopping and root plowing), and fire to manage woody vegetation in the Rio Grande Plains of southern Texas and northeastern Mexico. The model consists of two submodels representing dynamics of woody and herbaceous vegetation, respectively. Percent canopy cover of woody vegetation changes as the result of application

W. E Grant; Wayne T Hamilton; Esteban Quintanilla

1999-01-01

235

Control of Structure in Conventional Friction Stir Welds Through a Kinematic Theory of Metal Flow.  

National Technical Information Service (NTIS)

In friction stir welding (FSW), a rotating pin is translated along a weld seam so as to stir the sides of the seam together. Metal is prevented from flowing up the pin, which would result in plowing/cutting instead of welding, by a shoulder on the pin. In...

H. A. Rubisoff J. A. Nunes J. A. Schneider

2009-01-01

236

Tillage and soil carbon sequestration—What do we really know?  

Microsoft Academic Search

It is widely believed that soil disturbance by tillage was a primary cause of the historical loss of soil organic carbon (SOC) in North America, and that substantial SOC sequestration can be accomplished by changing from conventional plowing to less intensive methods known as conservation tillage. This is based on experiments where changes in carbon storage have been estimated through

John M. Baker; Tyson E. Ochsner; Rodney T. Venterea; Timothy J. Griffis

2007-01-01

237

Restoration of Disturbed Lands: The Hole-in-the-Donut Restoration in the Everglades  

Microsoft Academic Search

The Hole-in-the-Donut (HID) wetland restoration project was established on former agricultural land inside Everglades National Park, where rock plowing and fertilization had altered the hydrology, structure, depth, aeration, and nutrient content of soils. Following the cessation of farming, highly disturbed HID soils were invaded by dense, nearly monospecific stands of Brazilian pepper (Schinus terebinthifolius Raddi). Initial efforts to restore Brazilian

Craig S. Smith; Lauren Serra; Yuncong Li; Patrick Inglett; Kanika Inglett

2011-01-01

238

Fast oscillations and particle acceleration in the neutral sheet  

Microsoft Academic Search

This paper suggests that fast periodic oscillations in the neutral sheet occur after it is perturbed strongly. An analytic solution of the oscillation process, of which the period T is about 1 ms, is obtained on the basis of the snow-plow model. This dynamical process causes the periodic appearance and disappearance of a diffusive region in the sheet. A time

Jiu-Ping Ding; Cheng-Yue Zhang; Hong-Wei Li

1986-01-01

239

Meeting Mandatory Federal Health Standards Under Difficult Dust Control Conditions.  

National Technical Information Service (NTIS)

Respirable dust measurements made by coal mine inspectors during the first year of enforcement of the Coal Mine Health and Safety Act of 1969 established that the high-risk dust concentrations on the four longwall plows operating in Virginia were in the r...

J. J. Pendergast T. A. Cox W. H. Sutherland

1976-01-01

240

Meeting Mandatory Federal Health Standards under Difficult Dust-Control Conditions.  

National Technical Information Service (NTIS)

Respirable dust measurements made by coal mine inspectors during the first year of enforcement of the Coal Mine Health and Safety Act of 1969 established that the high-risk dust concentrations on the four longwall plows operating in Virginia were in the r...

J. J. Pendergast T. A. Cox W. H. Sutherland

1976-01-01

241

Earthmoving Operations under Winter Conditions: A Reference Manual (Proizvodstvo Zemlyanykh Rabot v Zimnikh Usloviyakh).  

National Technical Information Service (NTIS)

The most economical procedure for winter earthmoving operations is to prepare the soil in the Fall to prevent it from freezing. This is done by deep plowing, erecting snow fences or other means of insulating the soil. When such preparation is impossible, ...

V. A. Cherkashin V. P. Gorbanev

1971-01-01

242

At Paul Quinn, Students Till the Soil to Cultivate a Better College  

ERIC Educational Resources Information Center

In autumn, most colleges' football fields are covered with a thick carpet of grass or artificial turf and are adorned with yard lines. But the football field at Paul Quinn College was carved up by plowing and planting. This past fall, portions of the college's gridiron were covered with sweet potatoes, watermelons, peppers, rosemary, and sugar…

Kelderman, Eric

2012-01-01

243

Tillage and wind effects on soil CO 2 concentrations in muck soils  

Microsoft Academic Search

Rising atmospheric carbon dioxide (CO2) concentrations from agricultural activities prompted the need to quantify greenhouse gas emissions to better understand carbon (C) cycling and its role in environmental quality. The specific objective of this work was to determine the effect of no-tillage, deep plowing and wind speeds on the soil CO2 concentration in muck (organic) soils of the Florida Everglades.

D. C. Reicosky; R. W. Gesch; S. W. Wagner; R. A. Gilbert; C. D. Wente; D. R. Morris

2008-01-01

244

72 FR 17236 - Federal Motor Vehicle Safety Standards; Electronic Stability Control Systems; Controls and Displays  

Federal Register 2010, 2011, 2012, 2013

...most benign form of limit behavior. Mathematically, plow-out corresponds to the non-linear...than spin-out (Case 3, below). Mathematically, drift-out corresponds to the non-linear...off-road obstacles to tripped rollover. Mathematically, spin-out corresponds to the...

2007-04-06

245

Finite element analysis of the influence of tool edge radius on size effect in orthogonal micro-cutting process  

Microsoft Academic Search

The size effect in metal cutting is evident in the nonlinear scaling phenomenon observed in the specific cutting energy with decrease in uncut chip thickness. It has been argued by many researchers that this scaling phenomenon is caused mainly by the cutting tool edge radius, which purportedly affects the micro-cutting process by altering the effective rake angle, enhancing the plowing

Kai Liu; Shreyes N. Melkote

2007-01-01

246

Human osteology: key to the sequence of events in a postmortem shooting.  

PubMed

Forensic anthropologic examination of human skeletal remains found when a field was plowed provides evidence of both perimortem trauma, suggesting cause of death, and of subsequent shooting of the disarticulated skeleton. The case exemplifies the application of the specialized skills and knowledge of the physical anthropologist to determination of the postmortem sequence of events. PMID:1402762

Mann, R W; Owsley, D W

1992-09-01

247

Black Soldier Fly (Diptera: Stratiomyidae) Colonization of Pig Carrion in South Georgia  

Microsoft Academic Search

The black soldier fly, Hermetia illucens (L.), is thought to colonize corpses 20-30 days postmortem. However, recent observations indicate this might not be true for all cases. Therefore, we conducted a study examining colonization by the black soldier fly and other Diptera on pig carrion in a plowed field in southern Georgia from 20 September through 21 February. Our data

Jeffery K. Tomberlin; D. Craig Sheppard; John A. Joyce

2005-01-01

248

Evaluation of Nitrogen Application Technique and Tillage System on Nitrogen Runoff from an Erodible Soil.  

National Technical Information Service (NTIS)

Runoff studies were initiated in May 1985 on a highly erodible soil with slopes ranging from 4.6 to 13.8%. 100sq ft plots were divided into two tillage treatments: (1) no till and (2) conventional plow system. Within each tillage treatment, three nitrogen...

C. A. Lembi M. D. Britton M. A. Ross

1985-01-01

249

Challenges and Strategies Related to Hearing Loss among Dairy Farmers  

ERIC Educational Resources Information Center

Context: Farming is often imagined to be a serene and idyllic business based on historical images of a man, a horse, and a plow. However, machinery and equipment on farms, such as older tractors, grain dryers, and vacuum pumps, can have noise levels, which may be dangerous to hearing with prolonged, unprotected exposure. Purpose: This qualitative…

Hass-Slavin, Louise; McColl, Mary Ann; Pickett, William

2005-01-01

250

Improved Cutting Edges for Ice Removal.  

National Technical Information Service (NTIS)

Laboratory tests were performed with a hydraulic ice-cutting rig to determine the effects of the geometry of the cutting edge of a snow plow blade on the force required to remove ice from a highway pavement surface. Test results indicated that the most im...

W. A. Nixon

1993-01-01

251

Kinetics of Soil Particles on the Cutting Edge of Plowshares.  

National Technical Information Service (NTIS)

Knowledge of the process of cutting soil with a cutting edge leads to the study of many phenomena: wear of the cutting edge, instability of the path of travel of the plow, clogging of working tools with weeds, etc., no less important are the energetics of...

I. S. Tereshchenko

1969-01-01

252

Arsenic Fate And Transport In Red Cove, Fort Devens  

EPA Science Inventory

A field investigation was conducted to evaluate the impact of a discharging arsenic plume on sediment contamination in a cove (Red Cove) within Plow Shop Pond adjacent to Shepley's Hill Landfill at the Fort Devens Superfund Site in Massachusetts. Site characterization included a...

253

Arsenic Fate, Transport And Stability Study: Groundwater, Surface Water, Soil And Sediment Investigation At Fort Devens Superfund Site  

EPA Science Inventory

A field investigation was conducted to examine the distribution of arsenic in groundwater, surface water, and sediments at the Fort Devens Superfund Site. The study area encompassed a portion of plow Shop Pond (Red Cove), which receives groundwater discharge from the aquifer und...

254

Spin polarization vectors of field emitted electrons from Fe/W tips  

NASA Astrophysics Data System (ADS)

The atomic and electronic structures at the apex of W tips were studied by means of field ion microscopy and field emission microscopy, before and after the thermal deposition of a 5 nm Fe film. Two geometries of W tip, a conventional hemi-spherical type and a chisel (flat needle) type, were prepared. The hemispherical and the chisel W tips had a lang110rang direction parallel and perpendicular to the tip axis, respectively. The coated Fe films were found to be most likely in a non-crystalline phase, and to have a lower work function leading to a drastic change in electron emission from the apexes. The spin-polarization vectors of field-emitted electrons from these Fe/W tips were investigated with a Mott detector with a rotatable mechanism of tips. A similar absolute value of the spin-polarization vector \\vert {\\skew4\\vec{P}}_tip\\vert =0.415\\pm0.025 was obtained for each Fe/W, while the direction of the spin-polarization vector was dependent on the shape of the apex. The angle from the tip axis was ?=45° for the hemispherical apex and ?=66° for the chisel apex. A spin-polarized scanning tunneling microscopy setup with a rotation mechanism of such Fe/W tips made it possible to detect both the in-plane and the out-of-plane spin component of a sample magnetization.

Irisawa, T.; Yamada, T. K.; Mizoguchi, T.

2009-11-01

255

Assessment of strip tillage systems for maize production in semi-arid Ethiopia: Effects on grain yield, water balance and water productivity  

NASA Astrophysics Data System (ADS)

The Maresha, the traditional Ethiopian plow, requires repeated cross-plowing which causes increased surface runoff, less infiltration and hence lower water availability to crops. The main reasons for increased surface runoff and reduced infiltration are plowing along the slope and the formation of a plow pan at shallow depths. Conservation tillage is seen as a way to alleviate these problems. The widely advocated zero-tillage, however, is not feasible for smallholder farmers in semi-arid regions of Ethiopia because of difficulties in maintaining adequate soil cover, the practice of communal grazing, and high costs of herbicides. Strip tillage systems, on the other hand, may offer a solution. This study was initiated to test strip tillage systems and to evaluate the impacts of new tillage systems on the water balance and grain yields of maize. Experiments have been conducted in a semi-arid area called Melkawoba in the central Rift Valley of Ethiopia during 2003-2005. Strip tillage systems involved cultivation along planting lines at a spacing of 0.75 m using the Maresha plow followed by subsoiling along the same lines (STS) or without subsoiling (ST). Results have been compared with traditional tillage involving 3-4 overpasses with the Maresha plow (CONV). Soil moisture has been monitored to a depth of 1.8 m using a Time Domain Reflectometer (TDR) while surface runoff has been measured using a specially designed rectangular trough installed at the bottom of each plot. STS resulted in the least surface runoff (Qs = 18 mm season-1) and the highest grain yields (Y = 2130 kg ha-1) followed by ST (Qs = 26 mm season-1, Y = 1840 kg ha-1) and CONV (Qs = 43 mm season-1, Y = 1720 kg ha-1) provided sowing was carried out within a week after subsoiling. Thus, STS resulted in the highest water productivity, WP = 0.60 kg m-3, followed by ST (WP = 0.52 kg m-3) and CONV (WP = 0.48 kg m-3). The main conclusion of the paper is that even in dry areas reasonable yields can be obtained provided moisture conservation in the root zone is guaranteed. In this regard subsoiling is essential. Moreover, it is concluded that the time between subsoiling and planting is a key factor and should not exceed one week.

Temesgen, Melesse; Savenije, H. H. G.; Rockström, J.; Hoogmoed, W. B.

256

Factors associated with duck nest success in the prairie pothole region of Canada  

USGS Publications Warehouse

Populations of some dabbling ducks have declined sharply in recent decades and information is needed to understand reasons for this. During 1982-85, we studied duck nesting for 1-4 years in 17 1.6 by 16.0-km, high-density duck areas in the Prairie Pothole Region (PPR) of Canada, 9 in parkland and 8 in prairie. We estimated nest-initiation dates, habitat preferences, nest success, and nest fates for mallards (Anas platyrhynchos), gadwalls (A. strepera), blue-winged teals (A. discors), northern shovelers (A. clypeata), and northern pintails (A. acuta). We also examined the relation of mallard production to geographic and temporal variation in wetlands, breeding populations, nesting effort, and hatch rate.Average periods of nest initiation were similar for mallards and northern pintails, and nearly twice as long as those of gadwalls, blue-winged teals, and northern shovelers. Median date of nest initiation was related to presence of wet wetlands (contained visible standing water), spring precipitation, and May temperature. Length of initiation period was related to presence of wet wetlands and precipitation in May, June temperature, and nest success; it was negatively related overall to drought that prevailed over much of Prairie Canada during the study, especially in 1984.Mallards, gadwalls, and northern pintails nested most often in brush in native grassland, blue-winged teals in road rights-of-way, and northern shovelers in hayfields and small (<2 ha) untilled tracts of upland habitat (hereafter called Odd area). Among 8 habitat classes that composed all suitable nesting habitat of each study area, nest success estimates averaged 25% in Woodland, 19% in Brush, 18% in Hayland, 16% in Wetland, 15% in Grass, 11% in Odd area, 8% in Right-of-way, and 2% in Cropland. We detected no significant difference in nest success among species: mallard (11%), gadwall (14%), blue-winged teal (15%), northern shoveler (12%), and northern pintail (7%). Annual nest success (pooled by study area and averaged [unweighted] over all study areas) was 17% in 1982, 15% in 1983, 7% in 1984, and 14% in 1985.We estimated that predators destroyed 72% of mallard, gadwall, blue-winged teal, and northern shoveler nests and 65% of northern pintail nests. In prairie, average nest success decreased about 4 percentage points for every 10 percentage points increase in Cropland, suggesting that under conditions of 1982-85, local populations of these species probably were not stable when Cropland exceeded about 56% of available habitat. We found recent remains of 573 dead ducks during 1983-85; most were females (Anas spp.) apparently killed by predators. In some years, mallards and northern pintails were more numerous among dead ducks than we expected. More females than males were found dead among mallards and northern shovelers, suggesting higher vulnerability of females. Of factors we examined, nest-success rate appeared to be the most influential factor in determining mallard production. Nest success varied both geographically and annually.

Greenwood, R. J.; Sargeant, A. B.; Johnson, D. H.; Cowardin, L.; Shaffer, T. L.

1995-01-01

257

Selenium-vitamin E deficiency in captive wild ducks.  

PubMed

Seventy-five ducklings belonging to nine species of wild ducks were kept in a large floor pen. At about 8 weeks of age, a pintail and two shovelers showed clinical signs of anorexia, diarrhea, and leg weakness before death. Gross pathologic alterations included a pale discoloration of gizzard musculature and pale streaks in the leg muscle. Microscopic alterations in gizzard smooth-muscle cells included hyalinization, mineralization of sarcoplasmic debris in necrotic smooth-muscle fibers, and macrophagic invasion and phagocytosis of sarcoplasmic debris. Similar alterations were present in sections of skeletal leg muscle. The pathological lesions were characteristic of selenium-vitamin E deficiency. PMID:6870728

Dhillon, A S; Winterfield, R W

1983-01-01

258

LBNL Computational Research and Theory Facility Groundbreaking. February 1st, 2012  

SciTech Connect

Energy Secretary Steven Chu, along with Berkeley Lab and UC leaders, broke ground on the Lab's Computational Research and Theory (CRT) facility yesterday. The CRT will be at the forefront of high-performance supercomputing research and be DOE's most efficient facility of its kind. Joining Secretary Chu as speakers were Lab Director Paul Alivisatos, UC President Mark Yudof, Office of Science Director Bill Brinkman, and UC Berkeley Chancellor Robert Birgeneau. The festivities were emceed by Associate Lab Director for Computing Sciences, Kathy Yelick, and Berkeley Mayor Tom Bates joined in the shovel ceremony.

Yelick, Kathy

2012-01-01

259

LBNL Computational Research and Theory Facility Groundbreaking. February 1st, 2012  

ScienceCinema

Energy Secretary Steven Chu, along with Berkeley Lab and UC leaders, broke ground on the Lab's Computational Research and Theory (CRT) facility yesterday. The CRT will be at the forefront of high-performance supercomputing research and be DOE's most efficient facility of its kind. Joining Secretary Chu as speakers were Lab Director Paul Alivisatos, UC President Mark Yudof, Office of Science Director Bill Brinkman, and UC Berkeley Chancellor Robert Birgeneau. The festivities were emceed by Associate Lab Director for Computing Sciences, Kathy Yelick, and Berkeley Mayor Tom Bates joined in the shovel ceremony.

Yelick, Kathy

2013-05-29

260

LBNL Computational Research & Theory Facility Groundbreaking - Full Press Conference. Feb 1st, 2012  

SciTech Connect

Energy Secretary Steven Chu, along with Berkeley Lab and UC leaders, broke ground on the Lab's Computational Research and Theory (CRT) facility yesterday. The CRT will be at the forefront of high-performance supercomputing research and be DOE's most efficient facility of its kind. Joining Secretary Chu as speakers were Lab Director Paul Alivisatos, UC President Mark Yudof, Office of Science Director Bill Brinkman, and UC Berkeley Chancellor Robert Birgeneau. The festivities were emceed by Associate Lab Director for Computing Sciences, Kathy Yelick, and Berkeley Mayor Tom Bates joined in the shovel ceremony.

Yelick, Kathy

2012-01-01

261

An unusual case of non-syndromic occurrence of multiple dental anomalies.  

PubMed

Dental anomalies have been known to occur in humans due to a variety of genetic and environmental factors. Combinations of dental anomalies are known to be associated with specific syndromes. A few cases of multiple dental anomalies have been reported in patients with no generalized abnormalities. This case report describes an unusual occurrence of a combination of dental anomalies in an apparently normal healthy 12-year-old female patient. The dental anomalies in this patient were multiple dens invaginatus, generalized enamel hypoplasia, generalized microdontia, root resorption and multiple periapical lesions, shovel shaped incisors, cup shaped premolars, taurodontism, hypodontia and supernumerary teeth. PMID:19884730

Suprabha, B S; Sumanth, K N; Boaz, Karen; George, Thomas

2009-01-01

262

The use of blood in Anas clypeata as an efficient and non-lethal method for the biomonitoring of mercury.  

PubMed

Hg was analyzed in seven tissues of 52 common shoveler Anas clypeata collected from the coast of SE Gulf of California. Mean Hg concentrations were highest in the liver (2,885 ng g?¹) and lowest in the gizzard (621 ng g?¹); they followed the order: liver, feathers > muscle tissue and tissues of the circulatory system > digestive organs. Hg levels were similar or higher than birds of the same trophic level and feeding habits. Considering the relationships of Hg among tissues and blood we recommend the use of blood as an efficient method to monitor Hg. PMID:23595347

Raygoza-Viera, J R; Ruiz-Fernández, A C; Ruelas-Inzunza, J; Páez-Osuna, F

2013-07-01

263

NASA Shared Services Center breaks ground  

NASA Technical Reports Server (NTRS)

NASA officials and elected leaders were on hand for the groundbreaking ceremony of the NASA Shared Services Center Feb. 24, 2006, on the grounds of Stennis Space Center. The NSSC provides agency centralized administrative processing, human resources, procurement and financial services. From left, Louisiana Economic Development Secretary Mike Olivier, Stennis Space Center Director Rick Gilbrech, Computer Sciences Corp. President Michael Laphen, NASA Deputy Administrator Shana Dale, Rep. Gene Taylor, Sen. Trent Lott, Mississippi Gov. Haley Barbour, NASA Administrator Mike Griffin and Shared Services Center Executive Director Arbuthnot use golden shovels to break ground at the site.

2006-01-01

264

LBNL Computational Research & Theory Facility Groundbreaking - Full Press Conference. Feb 1st, 2012  

ScienceCinema

Energy Secretary Steven Chu, along with Berkeley Lab and UC leaders, broke ground on the Lab's Computational Research and Theory (CRT) facility yesterday. The CRT will be at the forefront of high-performance supercomputing research and be DOE's most efficient facility of its kind. Joining Secretary Chu as speakers were Lab Director Paul Alivisatos, UC President Mark Yudof, Office of Science Director Bill Brinkman, and UC Berkeley Chancellor Robert Birgeneau. The festivities were emceed by Associate Lab Director for Computing Sciences, Kathy Yelick, and Berkeley Mayor Tom Bates joined in the shovel ceremony.

Yelick, Kathy

2013-05-29

265

[Cardiovascular assessment in building activities using an ergospirometer].  

PubMed

We report preliminary results of a current study aimed to evaluated peak oxygen consumption and others cardiopulmonary exercise test parameters, in some common and tiring building activities, with the use of a portable ergospirometer stress test (Metamax 3B, Cortex Biophysik). We tested 3 Building School's Teachers of Seriate (Bergamo): the materials handling and transport of cement bricks and to dig with pick and shovel reaches peak anaerobic threshold into few minutes while the activity of make molter permits an aerobic metabolism in all building workers tested. PMID:14979167

Bigoni, F; Borleri, D; Seghizzi, P; Mosconi, G

2003-01-01

266

Friction and wear behavior of single-crystal silicon carbide in contact with titanium  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with single crystal silicon carbide in sliding contact with titanium. Results indicate that the friction coefficient is greater in vacuum than in argon and that this is due to the greater adhesion or adhesive transfer in vacuum. Thin films of silicon carbide transferred to titanium also adhered to silicon carbide both in argon at atmospheric pressure and in high vacuum. Cohesive bonds fractured on both the silicon carbide and titanium surfaces. The wear debris of silicon carbide created by fracture plowed the silicon carbide surface in a plastic manner. The friction characteristics of titanium in contact with silicon carbide were sensitive to the surface roughness of silicon carbide, and the friction coefficients were higher for a rough surface of silicon carbide than for a smooth one. The difference in friction results was due to plastic deformation (plowing of titanium).

Miyoshi, K.; Buckley, D. H.

1977-01-01

267

Friction and fracture of single-crystal silicon carbide in contact with itself and titanium  

NASA Technical Reports Server (NTRS)

An investigation was conducted to examine the friction properties and mechanical behavior of single-crystal silicon carbide (0001) surface sliding against itself and against polycrystalline titanium. The results indicate hexagon-shaped pits of silicon carbide and the formation of platelet hexagon-shaped wear debris of silicon carbide due to cleavages of both prismatic and basal planes as a result of silicon carbide sliding against itself. The fracturing of silicon carbide also occurs near the adhesive bond to titanium. The wear debris produced by brittle fracture plows the titanium and transfers to it. Further, the silicon carbide wear debris, which adhered and transferred to titanium, plows the silicon carbide surface and transfers back to it

Miyoshi, K.; Buckley, D. H.

1979-01-01

268

Experimental Oxidative Dissolution of Sphalerite in the Aznalcóllar Sludge and Other Pyritic Matrices  

Microsoft Academic Search

After the collapse on 25 Apr. 1998 of the Aznalcollar mine tailings dike in southwestern Spain, 45 km2 of the Guadiamar valley were coveredbyapyriticsludgecontainingupto2%sphalerite(ZnS).Later, the sludge was mechanically removed and calcium carbonate was plowed into the soil to immobilize heavy metals. By June 2001 more than 60% of the sulfides in the residual sludge had oxidized and soil Zn contents

Raúl Hita; José Torrent; Jerry M. Bigham

2006-01-01

269

Chronology of the spread of tamarisk in the central Rio Grande  

Microsoft Academic Search

Like many dryland rivers of the southwestern United States, the central Rio Grande suffered a collapse of its native cottonwood\\u000a forests and an expansion of tamarisk (Tamarix spp.) in the early 20th century. A paramount example of an opportunistic colonizer, tamarisk occupied land made available\\u000a by the plow, the bulldozer, and the shrinking of a channel depleted of flow by

Benjamin L. Everitt

1998-01-01

270

A near-infrared shock wave in the 2006 outburst of recurrent nova RS Ophiuchi  

Microsoft Academic Search

Near-infrared spectra are presented for the recent 2006 outburst of the\\u000arecurrent nova RS Ophiuchi (RS Oph).We report the rare detection of an infrared\\u000ashock wave as the nova ejecta plows into the pre-existing wind of the secondary\\u000ain the RS Oph system consisting of a white dwarf (WD) primary and a red giant\\u000asecondary. The evolution of the shock

Ramkrishna Das; Dipankar P. K. Banerjee; Nagarhalli M. Ashok

2006-01-01

271

Enhancing No-Tillage Systems for Corn with Starter Fertilizers, Row Cleaners, and Nitrogen Placement Methods  

Microsoft Academic Search

and 5 to 13% in Minnesota (Ford and Hicks, 3 factorial design included combinations of with or without row board plow) or residue type (corn vs. soybean). Because cleaners, 0.0 or 93.5 L ha2 1 (0 or 10 gal acre2 1 ) of 10-15-0 starter removal of residue from the seed row hastened emer- fertilizer, and N sources anhydrous ammonia

Jeffrey A. Vetsch; Gyles W. Randall

2000-01-01

272

Software first: applying Ada megaprogramming technology to target platform selection trades  

Microsoft Academic Search

The 14-state European Organization for the Safety of Air Navigation (EUROCONTROL) has recently completed its target platform selection analyses for the Central Flow Management Unit’s (CFMU) Tactical subsystem (TACT). TACT will provide support to CFMU and other users of the airspace in their tactical and pm-tactical Air Traffic Plow Management (A- activities for Europe. Its estimated size is about 160,000+

A. R. Filarey; W. E. Royce; R. Rao; P. Schmutz; L. Doan-Minh

1993-01-01

273

Using a remote sensing field experiment to investigate flux-footprint relations and flux sampling distributions for tower and aircraft-based observations  

Microsoft Academic Search

During a remote sensing field experiment conducted in the Southern Great Plains in 1997 (SGP97), tower and aircraft-based flux observations were collected over one of the main study sites in central Oklahoma. This is an agricultural region and contains primarily grassland\\/pasture and winter wheat, which was recently harvested leaving a significant number of fields either as wheat stubble or plowed

William P. Kustas; Martha C. Anderson; Andrew N. French; Dean Vickers

2006-01-01

274

Nutrient and Sediment Losses Under Simulated Rainfall Following Manure Incorporation by Different Methods  

Microsoft Academic Search

mended to minimize nutrient losses. A 3-yr study was conducted to evaluate sediment and nutrient losses with different tillage methods ents within the soil may increase the risk of nutrient (moldboard plow, heavy-duty cultivator, double disk, and no-incorpo- leaching. ration) for incorporation of beef cattle manure in a silage barley Rainfall and overland runoff generally interact with (Hordeum vulgare L.)

Joanne L. Little; D. Rodney Bennett; Jim J. Miller

2005-01-01

275

Characterization of dents and grooves on polymer films using scanning white light interferometry  

Microsoft Academic Search

Surface deformation inflicted on two different kinds of thin layered polymer films was investigated under static indentation and dynamic loading (plowing) at room temperature. Affecting the surface were polished spherical steel tips of 0.5-1.6 mm radii moving at 0.1-16.0 mm\\/s along the surface. A load of 2-5 N was applied on the tip normal to the surface. The surface response

Ivan Kassamakov; Kari Ojala; Ari Salmi; Edward Hæggström; Juha Aaltonen; Arne Huber; Heimo Saarikko; Mathias Österberg; Markku Oinonen

2006-01-01

276

Framing the Classroom: Pedagogy, Power, Oleanna  

Microsoft Academic Search

I open this essay with an admission: I have never been a fan of Oleanna. When I first heard about the play in early 1992, I was apprehensive. Given the problematic attitudes toward women in plays such as Sexual Perversity in Chicago, American Buffalo, and Speed-the-Plow—and the strident masculine poses of both the playwright and his dramatic characters—David Mamet seemed

Stanton B. Garner

277

Agroforestry systems and soil surface management of a tropical alfisol: I: Soil moisture and crop yields  

Microsoft Academic Search

Field experiments were conducted on a tropical Alfisol at Ibadan, Nigeria, to evaluate the effects on soil moisture and crop yields of three agroforestry systems. Effects of agroforestry treatments involving two perennial shrubs (Leucaena leucocephala and Gliricidia sepium), each at 2-m and 4-m row spacings, were compared with no-till and plow-till systems of seedbed preparation. Measurements were made for soil

R. Lal

1989-01-01

278

ERIP invention 637. Technical progress report 2nd quarter, April 1997--June 1997  

SciTech Connect

This technical report describes progress in the development of the Pegasus plow, a stalk and root embedding apparatus. Prototype testing is reported, and includes the addition of precision tillage. Disease data, organic matter, and nitrogen levels results are very briefly described. Progress in marketing is also reported. Current marketing issues include test use by cotton and wheat growers, establishment of dealer relationships, incorporation of design modifications, expansion of marketing activities, and expansion of loan and lease program.

Thacker, G.W.

1997-07-22

279

Conservation tillage for carbon sequestration  

Microsoft Academic Search

World soils represent the largest terrestrial pool of organic carbon (C), about 1550 Pg compared with about 700 Pg in the\\u000a atmosphere and 600 Pg in land biota. Agricultural activities (e.g., deforestation, burning, plowing, intensive grazing) contribute\\u000a considerably to the atmospheric pool. Expansion of agriculture may have contributed substantially to the atmospheric carbon\\u000a pool. However, the exact magnitude of carbon

R. Lal; J. M. Kimble

1997-01-01

280

The effect of soil tillage and fertilizer use on pearl millet yields in Niger  

Microsoft Academic Search

Farmers in Niger generally do not plow their fields and are therefore unable to incorporate phosphate. Experiments were conducted\\u000a in Niger to assess the effect of soil tillage, P source, and fertilizer placement on yields of pearl millet (Pennisetum glaucum [L.] R. Br.). Treatments included single superphosphate (SSP) or ground Tahoua phosphate rock (PRT) incorporated into the\\u000a soil during tillage

C. B. Christianson; A. Bationo; W. E. Baethgen

1990-01-01

281

Surface Roughness Parameter Uncertainties on Radar Based Soil Moisture Retrievals  

NASA Technical Reports Server (NTRS)

Surface roughness variations are often assumed to be negligible for the retrieval of sol moisture. Although previous investigations have suggested that this assumption is reasonable for natural vegetation covers (i.e. Moran et al. 2002), in-situ measurements over plowed agricultural fields (i.e. Callens et al. 2006) have shown that the soil surface roughness can change considerably due to weathering induced by rain.

Joseph, A. T.; vanderVelde, R.; O'Neill, P. E.; Lang, R.; Su, Z.; Gish, T.

2012-01-01

282

Effect of mechanical disturbances on nematode communities in arable land  

Microsoft Academic Search

Summary  Nematode communities were used as bioindicators of changes in agroecosystems caused by anthropogenic factors. The aim of this\\u000a study was to examine the impact of plowing and harrowing on nematode communities structure in comparison to “no tillage” treatments.\\u000a The effects of mechanical disturbing of nematodes were determined on four soil treatments. Differences in nematode community\\u000a structure were compared between two

M. Brmež; M. Ivezi?; E. Raspudi?

2006-01-01

283

Knowledge: Genuine and Bogus  

Microsoft Academic Search

\\u000a It has been said that humans can fake anything, even altruism and love, as well as science and philosophy. Some theories and\\u000a practices can be recognized at first sight as being bogus and unrecyclable. This is the case of palmistry, homeopathy, and\\u000a creation “science.” Others demand plowing through esoteric texts. This is the case of phenomenology, which its founder, Edmund

Mario Bunge

284

Soil microbial communities are affected more by land use than seasonal variation in restored grassland and cultivated Mollisols in Northeast China  

Microsoft Academic Search

Seasonal variations of soil microbial communities in a cultivated black soil (0–20 cm) with different fertilizing treatments [no fertilizer (NoF), chemical fertilizer (CF) and chemical fertilizer plus manure (CFM)] and in a neighboring plot of natural restoration (NR) in Northeast China were studied over a period of two years. The cultivated soils were plowed and had a rotation of maize–soybean–wheat. The

Zhenhua Yu; Guanghua Wang; Jian Jin; Judong Liu; Xiaobing Liu

2011-01-01

285

Effects of vegetable production system on epigeal arthropod populations  

Microsoft Academic Search

Populations of epigeal arthropods were monitored in vegetable production systems under varying degrees of sustainable agricultural practices in Fletcher, NC (USA). Two tillage types (conventional plow and disk, strip-tillage (ST)), two input approaches (chemically based, biologically based) and two cropping schedules (continuous tomato Lycopersicon esculentum Mill.], 3-year rotation of sweet corn [Zea mays L.]\\/cabbage [Brassica oleracea L.], cucumber [Cucumis sativus

Robert L Hummel; James F Walgenbach; Greg D Hoyt; George G Kennedy

2002-01-01

286

Microbial Distributions And Their Potential Controlling Factors In Terrestrial Subsurface Environments  

Microsoft Academic Search

Terrestrial subsurface environments (below the plow layer) contain an enormous amount of the earth’s biomass, yet are relatively\\u000a undersampled compared to topsoil, aquatic, and marine environments. Depth emerges as a primary axis for relating distributions\\u000a of microorganisms and the factors controlling their distribution. There is generally a sharp drop in microbial biomass, diversity,\\u000a and activity as organic-rich topsoils deepen to

R. Michael Lehman

287

Comparing soil surface roughness patterns at different colour and organic matter conditions using shadow analysis method  

NASA Astrophysics Data System (ADS)

The method based on the shadow analysis has shown to be one of the most convenient techniques to characterize SSR in the field when used in arid and semi-arid regions. However, the technique has not been proved with soils having more than 3% of organic matter and soil with very dark colours. In order to proof that the technique is able to function at field trials with soils richer in organic matter and with different colours, the project compared SSR resulting in 5 different types of soils after passing chisel. The main variation amongst the soils was the colour, brown soils, grey pale soils and yellow soils and the organic matter associated, 1 to 6%. All the plots measured 1m2 and were used for crop production. For each site 6 plots were considered and all the data was captured during summer time to avoid the influence of rain. The SSR obtained varied from 44 to 62% showing that the results were not significantly related to the darkness of colour and the content of organic matter. The variations were strongly related to the amount of clay found on different soils. This difference could be introduced by the difficulty in some cases to pass the chisel when soil is too dried since the acquisition of field data was done after chisel tool was passed on different sites. The parameters demonstrated that the method can be used to study the influence of wind and water erosion on soil surface at field conditions with independence of colour and organic matter properties.

García Moreno, R.; Diaz Alvarez, M. C.; Saa Requejo, A.; Guerrero López, F.

2012-04-01

288

An improved whole cell pertussis vaccine with reduced content of endotoxin  

PubMed Central

An improved whole cell pertussis vaccine, designated as Plow, which is low in endotoxicity due to a chemical extraction of lipo-oligosaccharide (LOS) from the outer membrane, was evaluated for safety, immunogenicity and potency, comparatively to a traditional whole cell pertussis vaccine. Current whole cell pertussis vaccines are effective but contain large quantities of endotoxin and consequently display local and systemic adverse reactions after administration. Endotoxin is highly inflammatory and contributes considerably to the reactogenicity as well as the potency of these vaccines. In contrast, acellular pertussis vaccines hardly contain endotoxin and are significantly less reactogenic, but their elevated costs limit their global use, especially in developing countries. In this paper, bulk products of Plow and a traditional whole cell vaccine, formulated as plain monocomponents or combined with diphtheria and tetanus toxoids (DTPlow or DTP, respectively) were compared by in vitro and in vivo assays. Chemical extraction of LOS resulted in a significant decrease in endotoxin content (20%) and a striking decline in endotoxin related toxicity (up to 97%), depending on the used in vitro or in vivo test. The LOS extraction did not affect the integrity of the product and, more importantly, did not affect the potency and/or stability of DTPlow. Moreover, hardly any differences in antibody and T-cell responses were observed. The development of Plow is a significant improvement regarding the endotoxicity of whole cell pertussis vaccines and therefore a promising and affordable alternative to currently available whole cell or acellular pertussis vaccines for developing countries.

Dias, Waldely Oliveira; van der Ark, Arno A.J.; Sakauchi, Maria Aparecida; Kubrusly, Flavia Saldanha; Prestes, Ana Fabiola R.O.; Borges, Monamaris Marques; Furuyama, Noemi; Horton, Denise S.P.Q.; Quintilio, Wagner; Antoniazi, Marta; Kuipers, Betsy; van der Zeijst, Bernard A.M.; Raw, Isaias

2013-01-01

289

Impacts of conservation tillage on the hydrological and agronomic performance of Fanya juus in the upper Blue Nile (Abbay) river basin  

NASA Astrophysics Data System (ADS)

Adoption of soil conservation structures (SCS) has been low in high rainfall areas of Ethiopia mainly due to crop yield reduction, increased soil erosion following breaching of SCS, incompatibility with the tradition of cross plowing and water-logging behind SCS. A new type of conservation tillage (CT) involving contour plowing and the construction of invisible subsoil barriers using a modified Maresha winged "subsoiler" is suggested as a means to tackle these problems as an integral part of the SCS. We investigated the effect of integrating the CT with SCS on the surface runoff, water-logging, soil loss, crop yield and plowing convenience. The new approach of conservation tillage has been compared with traditional tillage (TT) on 5 farmers' fields in a high rainfall area in the upper Blue Nile (Abbay) river basin. Test crops were wheat [triticum vulgare] and tef [eragrostis tef]. Farmers found CT convenient to apply between SCS. Surface runoff appeared to be reduced under CT by 48 and 15%, for wheat and tef, respectively. As a result, CT reduced sediment yield by 51 and 9.5%, for wheat and tef, respectively. Significantly reduced water-logging was observed behind SCS in CT compared to TT. Grain yields of wheat and tef increased by 35 and 10%, respectively, although the differences were not statistically significant apparently due to high fertility variations among fields of participating farmers. Farmers who tested CT indicated that they will continue this practice in the future.

Temesgen, M.; Uhlenbrook, S.; Simane, B.; van der Zaag, P.; Mohamed, Y.; Wenninger, J.; Savenije, H. H. G.

2012-12-01

290

Anthropogenic transformation of soils in the northern Ergeni Upland (studies at the first experimental plot of the Arshan'-Zelmen Research Station)  

NASA Astrophysics Data System (ADS)

The results of soil studies performed in 2005-2009 at the first experimental plot of the Arshan'-Zelmen Research Station of the Institute of Forest Science of the Russian Academy of Sciences are discussed. The post-reclamation state (about 55 years after reclamation) of the soils under forest shelterbelts and adjacent croplands in the rainfed agriculture was studied. The long-term efficiency of forest reclamation and crop-growing technologies developed in the 1950s by the Dokuchaev Soil Science Institute and the Institute of Forest to reclaim strongly saline solonetzic soils was proved. In 55 years, strongly saline sodic solonetzes with sulfate-chloride and chloride-sulfate composition of salts were replaced by agrogenic soils with new properties. Under forest shelterbelts, where deep (40-60 cm) plowing was performed, the soils were transformed into slightly saline solonetzic agrozems with slight soda salinization in the upper meter and with dealkalized plowed and turbated horizons (0-20(40) cm). Under the adjacent cropland subjected to the influence of the shelterbelts on the soil water regime, strongly saline solonetzes were transformed into solonchakous agrosolonetzes with slight soda salinization in the upper 50 cm. In the plow layer, the content of exchangeable sodium decreased to 4-12% of the sum of exchangeable cations. An increased alkalinity and the presence of soda were found in the middle-profile horizons of the anthropogenically transformed soils.

Novikova, A. F.; Konyushkova, M. V.

2013-03-01

291

Determination of respiration, gross nitrification and denitrification in soil profile using BaPS system.  

PubMed

A facility of BaPS (Barometric Process Separation) was used to determine soil respiration, gross nitrification and denitrification in a winter wheat field with depths of 0-7, 7-14 and 14-21 cm. N2O production was determined by a gas chromatograph. Crop root mass and relevant soil parameters were measured. Results showed that soil respiration and gross nitrification decreased with the increase of soil depth, while denitrification did not change significantly. In comparison with no-plowing plot, soil respiration increased significantly in plowing plot, especially in the surface soil of 0-7 cm, while gross nitrification and denitrification rates were not affected by plowing. Cropping practice in previous season was found to affect soil gross nitrification in the following wheat-growing season. Higher gross nitrification rate occurred in the filed plot with preceding crop of rice compared with that of maize for all the three depths of 0-7, 7-14 and 14-21 cm. A further investigation indicated that the nitrification for all the cases accounted for about 76% of the total nitrogen transformation processes of nitrification and denitrification and the N2O production correlated with nitrification significantly, suggesting that nitrification is a key process of soil N2O production in the wheat field. In addition, the variations of soil respiration and gross nitrification were exponentially dependent on root mass (P<0.001). PMID:17278751

Chen, Shu-Tao; Huang, Yao

2006-01-01

292

Lesser mealworm (Coleoptera: Tenebrionidae) emergence after mechanical incorporation of poultry litter into field soils.  

PubMed

Lesser mealworm, Alphitobius diaperinus (Panzer), emergence from North Carolina field soils was evaluated in a controlled experiment simulating land application of turkey litter and again in field studies. Adult lesser mealworms were buried in central North Carolina Cecil red clay at depths of 0, 8, 15, 23, and 30 cm and the beetles emerging from the soil counted 1, 3, 7, 10, 13, 17, 21, 24, and 28 d after burial. Beetles emerged from all depths and differences among depths were not significant. Beetles survived at least 28 d buried in the soil at depths < or =30 cm. In seasonal field studies, lesser mealworm emergence from clay soil with poultry litter incorporated by disk, mulch and plow was compared with emergence from plots with no incorporation. Incorporation significantly reduced beetle emergence when poultry litter containing large numbers of beetles was applied to clay field soils during the summer (F = 3.45; df = 3, 143; P = 0.018). Although mechanical incorporation of poultry litter reduced beetle emergence relative to the control, greatest reductions were seen in plowed treatments. Beetle activity was reduced after land application of litter during colder months. Generally, lesser mealworm emergence decreased with time and few beetles emerged from the soil 28 d after litter was applied. Similarly, mechanical incorporation of poultry litter into sandy soils reduced beetle emergence (F = 4.06; df = 3, 143; P < 0.008). In sandy soils typical of eastern North Carolina, disk and plow treatments significantly reduced beetle emergence compared with control. PMID:15765688

Calibeo-Hayes, Dawn; Denning, Steve S; Stringham, S Mike; Watson, D Wes

2005-02-01

293

Ultrasonic/Sonic Jackhammer  

NASA Technical Reports Server (NTRS)

An ultrasonic/sonic jackhammer (USJ) is the latest in a series of related devices. Each of these devices cuts into a brittle material by means of hammering and chiseling actions of a tool bit excited with a combination of ultrasonic and sonic vibrations. A small-scale prototype of the USJ has been demonstrated. A fully developed, full-scale version of the USJ would be used for cutting through concrete, rocks, hard asphalt, and other materials to which conventional pneumatic jackhammers are applied, but the USJ would offer several advantages over conventional pneumatic jackhammers.

Bar-Cohen, Yoseph; Sherrit, Stewart; Herz, Jack

2005-01-01

294

[Manolo Hugué: from sculpture to painting due to arthritis].  

PubMed

There are several artists that have suffered rheumatic diseases. Even then, they continued their creative activity. Paul Klee suffered from systemic sclerosis, Dufy and Renoir suffered from rheumatoid arthritis and Gaudí and Boticelli had systemic-onset juvenile idiopathic arthritis. The famous noucentism sculptor, Manolo Hugué, presented chronic polyarthritis that suggested rheumatoid arthritis. Although he underwent several treatments, such as hydrotherapy or diathermic therapy, he had to stop sculpting. Using the chisel was too painful for his hands. He began, then, painting and composing poetry. PMID:21794797

Pou, María Antonia; Díaz-Torné, Cesar; Azevedo, Valderilio F

2011-01-01

295

Modified lingual split technique for extraction of impacted mandibular third molars.  

PubMed

Critical evaluation of existing chisel and bur techniques for removal of impacted mandibular third molars reveals a high incidence of complications. Both approaches require creation of a buccal defect immediately distal to the second molar for the insertion of an elevator, which may cause pocketing to occur postoperatively. The method described here minimizes periosteal reflection, almost completely avoids loss of bone, and effectively reduces the use of rotary instrumentation. The planning of the soft tissue flaps and bony cuts assists in primary wound closure, obliteration of dead space, and reduction of postoperative morbidity. PMID:6930459

Lewis, J E

1980-08-01

296

A Body-Effect-Assisted NOR-type (BeNOR) Multilevel Flash Memory  

NASA Astrophysics Data System (ADS)

We propose a new Body-Effect-assisted NOR-type (BeNOR) flash memory for multilevel storage application. Body effect assisted self-convergent programming employs secondary electron injection but a different operation bias from the CHannel Initiated Secondary ELectron (CHISEL) flash. Accurately programmed states are accomplished by the linear dependence of VTH on the bit-line voltage; therefore, parallel multilevel programming and elimination or reduction of bit-by-bit verification can be achieved. In this paper, programming power consumption and reliability considerations are also assessed for efficient and long-term operation.

Wang, Yen-Sen; Tsai, Hong-Ping; Yang, Evans Ching-Song; King, Ya-Chin; Chen, Steve; Hsu, Charles Ching-Hsiang

2001-04-01

297

Application of lead isotopes to mineral exploration in glaciated terrains  

NASA Astrophysics Data System (ADS)

The 206Pb/204Pb ratios of fine-grained fractions from glacial tills indicate the presence of known Proterozoic volcanogenic massive sulfide deposits at Chisel Lake, near Snow Lake, Manitoba, Canada. Data from <2 ?m and other size fractions define a linear array on a 207Pb/204Pb vs. 206Pb/204Pb diagram, with a slope that yields an age similar to the age of the deposits and the surrounding country rocks. Some of the least radiogenic till samples were found down ice from the deposits, suggesting that the Pb isotopic compositions from till may provide a new approach to mineral exploration for massive sulfide deposits in glaciated terrains.

Bell, K.; Franklin, J. M.

1993-12-01

298

Economic system analysis of coal preconversion technology: phase I. Volume III. Surface coal mining methods and equipment. Interim report for the period August 1973--July 1975  

SciTech Connect

This report presents background information on present mining methods, operations, equipment and economics, in addition to problems and future trends. This information is required to support the development of the computerized modeling system which can be used to design large-scale surface coal mines. The modeling system is designed to handle the following five basic mining methods: (1) area stripping with draglines; (2) area stripping with shovels or loaders and trucks; (3) contour mining with draglines; (4) mountain top removal; and (5) dipping-seam open-pit mining. Each of these methods usually involves the following six operations: (a) topsoil removal, (b) overburden drilling and blasting, (c) overburden removal, (d) coal drilling and blasting, (e) coal loading and hauling, and (f) land reclamation. Data on track-type tractors, loading shovels, motor graders, rotary drills, scrapers, track-type loaders, trucks, walking draglines, wheel loaders, and wheel-type tractors were compiled and incorporated into computer data files for direct use of the modeling system. Mining costs are composed of capital, startup, and operating costs. Based on discounted cash flows for different return on investment rates, the FOB selling price of coal for given coal deposits will be determined in Phase II. (auth)

Not Available

1975-07-01

299

Mx gene diversity and influenza association among five wild dabbling duck species (Anas spp.) in Alaska  

PubMed Central

Mx (myxovirus-resistant) proteins are induced by interferon and inhibit viral replication as part of the innate immune response to viral infection in many vertebrates. Influenza A virus appears to be especially susceptible to Mx antiviral effects. We characterized exon 13 and the 3’ UTR of the Mx gene in wild ducks, the natural reservoir of influenza virus and explored its potential relevance to influenza infection. We observed a wide range of intra- and interspecies variation. Total nucleotide diversity per site was 0.0014, 0.0027, 0.0044, 0.0051, and 0.0061 in mallards, northern shovelers, northern pintails, American wigeon, and American green-winged teals, respectively. There were 61 haplotypes present across all five species and four were shared among species. Additionally, we observed a significant association between Mx haplotype and influenza infection status in northern shovelers. However, we found no evidence of balancing or diversifying selection in this region of the Mx gene. Characterization of the duck Mx gene is an important step in understanding how the gene may affect disease resistance or susceptibility in wild populations. Furthermore, given that waterfowl act as a natural reservoir for influenza virus, the Mx gene could be an important determinant in the ecology of the virus.

Dillon, Danielle; Runstadler, Jonathan

2010-01-01

300

Grinding energy and mechanisms for ceramics  

NASA Astrophysics Data System (ADS)

A technological basis for efficient ceramic machining requires a fundamental understanding of the prevailing grinding mechanisms. Most past research on grinding mechanisms for ceramics has followed either the "indentation fracture mechanics" approach or the "machining" approach. The indentation fracture mechanics approach likens abrasive workpiece interactions to idealized small-scale indentations. The machining approach typically involves measurement of cutting forces together with microscopic observations of grinding debris and surfaces produced. Both approaches provide important insights into the grinding mechanisms for ceramic materials. However, up to now, no physical model has been presented which can quantitatively account for the energy associated with grinding of ceramics. The present research was undertaken to investigate grinding mechanisms for ceramics and to account for the energy expended. SEM observations of grinding debris for various ceramics and a glass over a wide range of conditions indicate material removal mainly by brittle fracture associated with lateral cracking and crushing. However, the ground surfaces reveal extensive ductile flow with characteristic scratches along the grinding direction and smearing. Ductile flow typically extends to a depth of 1-5 mum below the ground surface. For silicon nitride, etching with hydrofluoric acid removed the smeared layer, which would indicate that it consists of a glassy phase probably formed by oxidation at elevated grinding temperatures. Although material removal appears to occur mainly by brittle fracture, most of the grinding energy is apparently associated with ductile flow. An order of magnitude analysis indicates that the energy expended by brittle fracture constitutes a negligible portion of the total grinding energy. An upper bound plowing analysis is presented which can account the specific energy in terms of the geometry of the plowed groove. A new model has been developed which relates the grinding power to the rate of plowed surface area generated by the diamond cutting points on the wheel surface interacting with the workpiece. Over a wide range of grinding conditions, the power increases approximately proportionally with the rate of surface area generated, which suggests a nearly constant energy per unit area of plowed surface. Values obtained for energy per area for plowing are much bigger than the corresponding fracture surface energies, which further indicates that most of the grinding energy is associated with ductile flow.

Hwang, Tae Wook

301

Powder-Collection System for Ultrasonic/Sonic Drill/Corer  

NASA Technical Reports Server (NTRS)

A system for collecting samples of powdered rock has been devised for use in conjunction with an ultrasonic/sonic drill/corer (USDC) -- a lightweight, lowpower apparatus designed to cut into, and acquire samples of, rock or other hard material for scientific analysis. The USDC includes a drill bit, corer, or other tool bit, in which ultrasonic and sonic vibrations are excited by an electronically driven piezoelectric actuator. The USDC advances into the rock or other material of interest by means of a hammering action and a resulting chiseling action at the tip of the tool bit. The hammering and chiseling actions are so effective that unlike in conventional twist drilling, a negligible amount of axial force is needed to make the USDC advance into the material. Also unlike a conventional twist drill, the USDC operates without need for torsional restraint, lubricant, or a sharp bit. The USDC generates powder as a byproduct of the drilling or coring process. The purpose served by the present samplecollection system is to remove the powder from the tool-bit/rock interface and deliver the powder to one or more designated location(s) for analysis or storage

Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Chang, Zensheu; Blake, David; Bryson, Charles

2005-01-01

302

Effects of foreign object damage from small hard particles on the high-cycle fatigue life of titanium-(6)aluminum-(4)vanadium  

NASA Astrophysics Data System (ADS)

Thin rectangular samples of Ti-6Al-4V were damaged by four methods to represent foreign object damage found in turbine engine blades: (1) impact with 2 mm. and 5 mm diameter glass spheres at 305 m/s, (2) impact with 2 mm and 4 mm diameter steel spheres at 305 m/s, (3) quasi-static displacement controlled indentation using steel chisels with 1 mm, 2 nun and 5 mm diameter tips and (4) shearing notches with a 2 mm. diameter chisel point under a quasi-static loading condition. Finite element analysis was used to study the relationship between the stress state created by the plastic damage and the fatigue strength. A new method of quantifying the amount of plastic damage from multiple methods was developed. The fatigue strength required for crack initiation at 10E7 cycles was found to be a function of the total depth from the edge of the undeformed specimen up to the end of the plastically deformed zone. For damage depths less than 1750 mum, the reduction in fatigue strength is proportional to the depth of total damage. For depths > 1750 mum, there appears to be a threshold value of fatigue strength.

Hamrick, Joseph L., II

303

Differences in bill form of the oystercatcher haematopus ostralegus; a dynamic adaptation to specific foraging techniques  

NASA Astrophysics Data System (ADS)

In wintering European oystercatchers 3 bill types: pointed, chisel-shaped, and blunt were found as well as their intermediates. The distribution of the different bill types varied widely in both time and space. Pointed bills had a larger mean length than both chisel-shaped and blunt bills, and occurred more often in young birds than in adults, and more often in females than in males. On an average, females had longer bills than males. In oystercatchers in the Wadden Sea area bill length was found to increase with age, but in the Delta area no increase was found. In semi-natural cage experiments each bill type proved to be most suitable for a specific manner of localization and handling of prey. Bills of individual oystercatchers were shown to change shape when the bird was forced to change its feeding method. A change in method accompanied by a gradual change in bill form only caused a temporary loss of feeding efficiency. It is concluded that differences in bill length influence prey choice and feeding method and hence induce different bill forms. Age- and sex-dependent differences in bill length and form, together with the ability of the individual to adapt bill form and feeding behaviour, enable the oystercatcher to lessen interspecific competition and to respond to changing environmental conditions.

Swennen, C.; De Bruijn, L. L. M.; Duiven, P.; Leopold, M. F.; Marteijn, E. C. L.

304

Age-class separation of blue-winged ducks  

USGS Publications Warehouse

Accurate determination of age is of fundamental importance to population and life history studies of waterfowl and their management. Therefore, we developed quantitative methods that separate adult and immature blue-winged teal (Anas discors), cinnamon teal (A. cyanoptera), and northern shovelers (A. clypeata) during spring and summer. To assess suitability of discriminant models using 9 remigial measurements, we compared model performance (% agreement between predicted age and age assigned to birds on the basis of definitive cloacal or rectral feather characteristics) in different flyways (Mississippi and Pacific) and between years (1990-91 and 1991-92). We also applied age-classification models to wings obtained from U.S. Fish and Wildlife Service harvest surveys in the Mississippi and Central-Pacific flyways (wing-bees) for which age had been determined using qualitative characteristics (i.e., remigial markings, shape, or wear). Except for male northern shovelers, models correctly aged lt 90% (range 70-86%) of blue-winged ducks. Model performance varied among species and differed between sexes and years. Proportions of individuals that were correctly aged were greater for males (range 63-86%) than females (range 39-69%). Models for northern shovelers performed better in flyway comparisons within year (1991-92, La. model applied to Calif. birds, and Calif. model applied to La. birds: 90 and 94% for M, and 89 and 76% for F, respectively) than in annual comparisons within the Mississippi Flyway (1991-92 model applied to 1990-91 data: 79% for M, 50% for F). Exclusion of measurements that varied by flyway or year did not improve model performance. Quantitative methods appear to be of limited value for age separation of female blue-winged ducks. Close agreement between predicted age and age assigned to wings from the wing-bees suggests that qualitative and quantitative methods may be equally accurate for age separation of male blue-winged ducks. We interpret annual and flyway differences in remigial measurements and reduced performance of age classification models as evidence of high variability in size of blue-winged ducks' remiges. Variability in remigial size of these and other small-bodied waterfowl may be related to nutrition during molt.

Hohman, W.L.; Moore, J.L.; Twedt, D.J.; Mensik, J.G.; Logerwell, E.

1995-01-01

305

Post-fire hydrologic response in Central Portugal. A four years study at microplot scale.  

NASA Astrophysics Data System (ADS)

Wildfires are a natural phenomenon in regions with a Mediterranean-type climate. However, their present-day widespread occurrence in southern Europe is unprecedented and strongly reflects human activity such as ignition, land-use changes, land abandonment and introduction of highly flammable plantations. Besides wildfires, post-fire management practices such as plowing, terracing, clearcutting and logging should also be considered, since their occurrence is getting increasingly common. And, in a long-term period these practices seem to be executed intercalated with repeated fire occurrences in the same site, sharing the impacts together with fire in an escalated degradational effect. In this sense, the work presented here concerns four years of runoff and erosion data at microplot scale after the wildfire, comparing different land management practices that occurred before the fire. Preliminary results indicate that in four years of monitoring, runoff is constantly higher in plowed sites than in the unplowed ones, with the exception of the first year. Regarding soil losses the plowed plots present always higher sediment rates than the unplowed ones. The comparison between two unplowed sites with different land uses, indicate higher runoff and erosion risk for pine comparatively to the eucalypt ones, however the reduced soil depth in the first can have an important role in these differences. Following these facts, the aim of the present work is to answer the following research questions: i) Do these four years of observations fit with the window of disturbance model presented by Prosser and Williams (1998). or the alternative version by Wittenberg and Inbar (2009)?; ii) Does pre-fire disturbances (wildfire, land use changes and land management practices) still have repercussions after wildfire?; In what sense does four years of intensive monitoring provides that one year couldn't provide?

Vieira, Diana; Malvar, Maruxa; Martins, Martinho; Machado, Ana; Nunes, João; Keizer, Jacob

2014-05-01

306

Transformation and sorption of the veterinary antibiotic sulfadiazine in two soils: a short-term batch study  

NASA Astrophysics Data System (ADS)

The worldwide use of veterinary antibiotics poses a continuous threat to the environment. There is, however, a lack of mechanistic studies on sorption and transformation processes for environmental assessment in soils. Two-weeks batch sorption experiments were performed with the antibiotic sulfadiazine (SDZ) in the plow layer and the subsoil of a loamy sand and a silty loam. The sorption and transformation parameters of SDZ and its main transformation products N1-2-(4-hydroxypyrimidinyl) benzenesulfanilamide (4-OH-SDZ) and 4-(2-iminopyrimidin-1(2H)-yl)-aniline (An-SDZ) were estimated using a global optimization algorithm. A two-stage, one-rate kinetic sorption model combined with a first-order transformation model adequately described the batch data. Sorption of SDZ was nonlinear (Freundlich), time-dependent, and affected by pH (speciation), with a higher sorption capacity for the loamy sand. Transformation of SDZ into 4-OH-SDZ occurred only in the liquid phase, with half-life values of about 1 month in the plow layers and about 6 months in the subsoils. Both the faster transformation rate in the plow layer compared to the subsoil and negligible transformation in the solid phase point to a microbial process for the formation of 4-OH-SDZ. Under the exclusion of light, An-SDZ was formed in substantial amounts in the silty loam only, with liquid phase half-life values of about 2 to 3 weeks. Despite the rather large parameter uncertainties, which may be reduced after the inclusion of additional information obtained from sequential solid phase extraction, the proposed method allows us to quantify and predict the fate of antibiotics in soils.

Kasteel, Roy; Mboh, Cho; Unold, Myriam; Groeneweg, Joost; Vanderborght, Jan; Vereecken, Harry

2010-05-01

307

Cross-Site Soil Microbial Communities under Tillage Regimes: Fungistasis and Microbial Biomarkers  

PubMed Central

The exploitation of soil ecosystem services by agricultural management strategies requires knowledge of microbial communities in different management regimes. Crop cover by no-till management protects the soil surface, reducing the risk of erosion and nutrient leaching, but might increase straw residue-borne and soilborne plant-pathogenic fungi. A cross-site study of soil microbial communities and Fusarium fungistasis was conducted on six long-term agricultural fields with no-till and moldboard-plowed treatments. Microbial communities were studied at the topsoil surface (0 to 5 cm) and bottom (10 to 20 cm) by general bacterial and actinobacterial terminal restriction fragment length polymorphism (T-RFLP) and phospholipid fatty acid (PLFA) analyses. Fusarium culmorum soil fungistasis describing soil receptivity to plant-pathogenic fungi was explored by using the surface layer method. Soil depth had a significant impact on general bacterial as well as actinobacterial communities and PLFA profiles in no-till treatment, with a clear spatial distinction of communities (P < 0.05), whereas the depth-related separation of microbial communities was not observed in plowed fields. The fungal biomass was higher in no-till surface soil than in plowed soil (P < 0.07). Soil total microbial biomass and fungal biomass correlated with fungistasis (P < 0.02 for the sum of PLFAs; P < 0.001 for PLFA 18:2?6). Our cross-site study demonstrated that agricultural management strategies can have a major impact on soil microbial community structures, indicating that it is possible to influence the soil processes with management decisions. The interactions between plant-pathogenic fungi and soil microbial communities are multifaceted, and a high level of fungistasis could be linked to the high microbial biomass in soil but not to the specific management strategy.

Yrjala, Kim; Alakukku, Laura; Palojarvi, Ansa

2012-01-01

308

Cross-site soil microbial communities under tillage regimes: fungistasis and microbial biomarkers.  

PubMed

The exploitation of soil ecosystem services by agricultural management strategies requires knowledge of microbial communities in different management regimes. Crop cover by no-till management protects the soil surface, reducing the risk of erosion and nutrient leaching, but might increase straw residue-borne and soilborne plant-pathogenic fungi. A cross-site study of soil microbial communities and Fusarium fungistasis was conducted on six long-term agricultural fields with no-till and moldboard-plowed treatments. Microbial communities were studied at the topsoil surface (0 to 5 cm) and bottom (10 to 20 cm) by general bacterial and actinobacterial terminal restriction fragment length polymorphism (T-RFLP) and phospholipid fatty acid (PLFA) analyses. Fusarium culmorum soil fungistasis describing soil receptivity to plant-pathogenic fungi was explored by using the surface layer method. Soil depth had a significant impact on general bacterial as well as actinobacterial communities and PLFA profiles in no-till treatment, with a clear spatial distinction of communities (P < 0.05), whereas the depth-related separation of microbial communities was not observed in plowed fields. The fungal biomass was higher in no-till surface soil than in plowed soil (P < 0.07). Soil total microbial biomass and fungal biomass correlated with fungistasis (P < 0.02 for the sum of PLFAs; P < 0.001 for PLFA 18:2?6). Our cross-site study demonstrated that agricultural management strategies can have a major impact on soil microbial community structures, indicating that it is possible to influence the soil processes with management decisions. The interactions between plant-pathogenic fungi and soil microbial communities are multifaceted, and a high level of fungistasis could be linked to the high microbial biomass in soil but not to the specific management strategy. PMID:22983972

Sipilä, Timo P; Yrjälä, Kim; Alakukku, Laura; Palojärvi, Ansa

2012-12-01

309

A comparison of collisions of saltating grains with loose and consolidated silt surfaces  

NASA Astrophysics Data System (ADS)

A particle tracking velocimetry system was used to study the trajectories of saltating sand particles as they impacted either consolidated (solid) or unconsolidated (loose) silt surfaces in a wind tunnel. The tunnel friction velocity varied between 0.26 and 0.3 m s-1. The average coefficient of restitution, defined as the ratio of postcollision velocity to precollision velocity, was found to be $\\epsilon$ = 0.64 for the loose bed and $\\epsilon$ = 0.79 for the solid bed, respectively. The average ratio of energy loss to impact energy was found to be EL/E0 = 0.58 for the loose bed and EL/E0 = 0.37 for the solid bed, respectively. These indices demonstrate that the loose bed absorbs more momentum and energy from the impacting sand particle. The average ejection angle was lower at 18° for the loose bed than 23° for the solid bed. In the loose surface, crater formations were observed to form with each impact. Surface profile measurements suggest an average crater volume of >0.1 mm3. For both beds, the coefficient of restitution decreases with the particle impact speed. In the case of the solid bed, the dependence on impact speed is in good agreement with a model of two colliding spheres with identical material properties. With regard to the loose bed, a model of the impacting particle motion as it plows through and plastically deforms the bed material is tested. If the ratio of the horizontal to vertical forces on the particle as it plows through the bed is taken as a linear function of impact speed, the model is in good agreement with measured data. This suggests that compaction of the surface may occur along with the plowing and displacement of loose bed material.

Gordon, Mark; McKenna Neuman, Cheryl

2009-11-01

310

Longwall mining of thin seams  

SciTech Connect

Thin seam operations pose a challenge to the ingenuity of mining engineers to overcome the factor of human inconvenience in the restricted environment and associated high cost production. Surprisingly, low seam longwalls in the Federal Republic of Germany in an average thickness of 35 in. and dipping less than 18/sup 0/ come close to achieving the average production rate of all German longwall operations. They are all plow faces, and a consistent production of 3300 tons per day and a productivity of 40 tons per man shift are reported from one of the thin seam longwalls. These results were attained by reliable high-capacity equipment and roof support by shields that can be collapsed to as low as 22 inches. Maximum mining height for plow operated faces lies at 31.5 inches. Technology for mechanized mining of flat lying coalbeds less than 31.5 inches in thickness without rock cutting is not available, and firmness of coal, undulation of the strata, coalbed thickness variation, and the necessity of cutting rock, particularly through faults, set limits to plow application. The in-web shearer can be used in firm coal to a minimum mining height of 40 inches, and a daily production of 1650 to 2200 tons is reported from a longwall in the Saar district of Germany equipped with such a shearer and shields. Numerous in-web shearers are employed in the United Kingdom; reports as to their success are contradictory. Also, experience in the United States, though limited, has been negative. The steady increase in output from single drum shearer faces in Pennsylvania is a remarkable achievement, and occasional record breaking peaks in production indicate the potential of such mining. Technology development for the future is discussed.

Curth, E A

1981-01-01

311

Human energy expenditure in lowland rice cultivation in Malaysia.  

PubMed

A study was undertaken to evaluate the human energy consumption of various field operations involved in lowland rice cultivation in Malaysia. Based on recorded average heart rates, fertilizing was found to be the most strenuous operation, with an average heart rate of 138 beats min(-1). There were no significant differences in the average heart rates of the subjects among the individual tasks within the first plowing, second plowing, and harvesting operations, with the average heart rates for these three tasks being 116, 106, and 106 beats min(-1), respectively. The corresponding energy expenditures were 3.90, 3.43, and 3.35 kcal min(-1). Loading the seed into the blower tank and broadcasting the seed were the most critical tasks for the seed broadcasting operation, with average heart rates of 124 and 136 beats min(-1), respectively. The highest energy expenditure of 418.38 kcal ha(-1) was observed for seed broadcasting, and the lowest energy expenditure of 127.96 kcal ha(-1) was for second plowing. The total seasonal human energy expenditure for rice cultivation was estimated to be 5810.71 kcal ha(-1), 55.7% of which was spent on pesticide spraying. Although the sample size in this study was relatively small, the results indicated that human energy expenditure per unit area (kcal ha(-1)) was positively linked to the average heart rate of the subjects and negatively linked to the field capacity. Thus, mechanization of certain tasks could decrease worker physical effort and fatigue and increase production. PMID:22458015

Nawi, N M; Yahya, A; Chen, G; Bockari-Gevao, S M; Maraseni, T N

2012-01-01

312

Impact of conservation agriculture on harnessing sustainability and building resilience against land degradation in the northern Ethiopian highlands  

NASA Astrophysics Data System (ADS)

Conservation Agriculture (CA) aims at improving soil quality and crop yield whilst reducing runoff and topsoil erosion which raises the soil resilience to combat soil degradation. Different chemical, physical, and biological properties of a soil interact in complex ways that determine the crop productivity potential of the soil. Hence, a medium-term tillage experiment was carried out (2005 to 2011) on a Vertisol to evaluate changes in soil quality, runoff and soil loss due to CA-based field conservation practices in northern Ethiopia. The experimental layout was implemented in a randomized complete block design with three replications on permanent plots of 5 m by 19 m. The tillage treatments were derdero+ (DER+) with a furrow and permanent raised bed planting system, plowed once at planting by refreshing the furrow and with 30% standing crop residue retention, terwah+ (TER+) with plowing once at planting with 30% standing crop residue retention and contour furrows made at 1.5 m distance interval, and conventional tillage (CT) with a minimum of three tillage operations and removal of crop residues. All the plowing and reshaping of the furrows was done using the local ard plow mahresha. Local crop rotation practices followed during the seven years sequentially from the first to the seventh year included wheat-teff-wheat-barley-wheat-teff-grass pea. Glyphosate was sprayed starting from the third year (2007) at 2 l ha-1 before planting to control pre-emergent weed in DER+ and TER+. Significantly different (p<0.05) mean runoff coefficients (%) in 7-yrs of 13, 20 and 27 were recorded for DER+, TER+ and CT, respectively. Mean soil losses of 7-yrs were 4.4, 12.5 and 18 t ha-1 y-1 in DER+, TER+ and CT, respectively. Among the several assessed soil properties, SOM, N, P, soil microbial biomass carbon, aggregate stability index, consistency index, cone index, air capacity and macroporosity were shown to significantly increase in soils subjected to DER+ planting system compared to CT, specifically at 0-10 cm depth. Aggregate instability index, crack size at harvest, relative water capacity and plastic limit were significantly larger in CT compared to CA treatments. Adoption of improved local practices of DER+ and TER+ planting systems that employ conservation agriculture principles can reduce runoff, soil loss and improve crop yield and soil quality and thus, sustainability in Vertisols. Keywords: Soil resilience, Vertisol, conservation agriculture, field conservation practices, soil quality

Araya, Tesfay; Cornelis, Wim M.; Govaerts, Bram; Bauer, Hans; Deckers, Jozef; Nyssen, Jan

2013-04-01

313

Self-revegetation of disturbed ground in the deserts of Nevada and Washington  

SciTech Connect

Plant cover established without purposeful soil preparation or seeding was measured on ground disturbed by plowing in Washington and by aboveground nuclear explosions in Nevada. After a time lapse of three decades in Washington and two decades in Nevada, fewer species were self-established on the disturbed ground than the nearby undisturbed ground. Alien annual plants were the dominants on the disturbed ground. Cheatgrass (Bromus tectorum) dominated abandoned fields in Washington, and filaree (Erodium cicutarium) dominated disturbed ground in Nevada. Perennial grasses and shrubs appeared to be more successful as invaders in Nevada than in Washington. This distinction is attributed to the superior competitive ability of cheatgrass in Washington.

Rickard, W.H.; Sauer, R.H.

1982-01-01

314

Cropping management using color and color infrared aerial photographs  

NASA Technical Reports Server (NTRS)

The Universal Soil Loss Equation (USLE) is a widely accepted tool for erosion prediction and conservation planning. Solving this equation yields the long-term average annual soil loss that can be expected from rill and inter-rill erosion. In this study, manual interpretation of color and color infrared 70 mm photography at the scale of 1:60,000 is used to determine the cropping management factor in the USLE. Accurate information was collected about plowing practices and crop residue cover (unharvested vegetation) for the winter season on agricultural land in Pheasant Branch Creek watershed in Dane County, Wisconsin.

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

1979-01-01

315

Effect of Cultural Practices, Soil Phosphorus, Potassium, and pH on the Incidence of Fusarium Head Blight and Deoxynivalenol Levels in Wheat  

PubMed Central

In a survey conducted in 1984 in Essex, Lambton, and Middlesex Counties of Ontario, Canada, greater incidences of head blight and greater concentrations of deoxynivalenol in grain were observed in fields of winter wheat planted after corn than in those planted after soybeans, barley, and mixed grains. Neither head blight nor deoxynivalenol level were correlated significantly with soil P, K, or pH. Head blight was reduced in wheat planted after corn where the residues from a preceding corn crop were plowed down or where seed was treated with Vitaflo 280. However, head blight and deoxynivalenol levels were not affected significantly by the level of N application, cultivar, other diseases or herbicides.

Teich, A. H.; Hamilton, J. R.

1985-01-01

316

Restoration of a Freshwater Wetland on Subsided Peat Soils: Potential Effects on Release of Dissolved Organic Carbon and Disinfection Byproduct Precursors  

NASA Astrophysics Data System (ADS)

In 1997, a wetland restoration demonstration project began on Twitchell Island in the Sacramento-San Joaquin Delta (Delta), California, to examine the effects of a permanently flooded, freshwater wetland on peat soil subsidence. Conversion from agriculture to wetland has changed many of the biogeochemical processes controlling dissolved organic carbon (DOC) production, release, and transport from the peat soils, relative to the previous agricultural land uses. This study explores the effects of agricultural and wetland management on peat soil biogeochemistry of DOC and disinfection byproduct (DBP) precursor release. DBPs [e.g. trihalomethanes (THMs)] form when chlorine reacts with the natural organic matter present in source drinking water. Many DBPs are carcinogenic and mutagenic and pose a potential threat to more than 22 million Californians whose drinking water is diverted from the Delta. Results indicate that previous drainage practices substantially affected the quantity of water-soluble DOC currently extractable from Delta peat soils and ranged from 0.40 mg C (carbon)/g soil for well-drained soils to 0.76 mg C/g soil for poorly drained soils. Present management also affects the propensity of this DOC to form DBPs. The following values for DBP formation were measured for a variety of soil types and depths (all values are medians in mmole THMs produced/mole C): well-drained agricultural field (7.7 plow layer, 7.9 below plow layer), poorly drained agricultural field (7.0 plow layer, 8.7 below plow layer), open-water wetland (12.8 sediment, 10.1 underlying soil), and vegetated wetland (11.3 sediment, 7.7 underlying soil). Sources of organic matter inputs and decomposition pathways seem to be important factors in DBP precursor formation and release when DOC loadings are of similar magnitude. These results indicate that soil conditions have a greater effect on DOC and DBP loadings than any differences caused by conversion from agriculture to wetland, which is of great importance in Delta restoration efforts.

Fleck, J.; Fujii, R.; Bossio, D.

2002-12-01

317

Ground control failures. A pictorial view of case studies  

SciTech Connect

The book shows, in pictorial views, many forms and/or stages of types of failures in mines, for instance, cutter, roof falls, and cribs. In each case, the year of occurrence is stated in the beginning so that the environment or technological background under which it occurred are reflected. The narrative than begins with the mining and geological conditions, followed by a description of the ground control problems and recommended solutions and results, if any. The sections cover failure of pillars, roof falls, longwall, roof bolting, multiple-seam mining, floor heave, longwall, flooding and weathering of coal, old workings, and shortwall and thin-seam plow longwall.

Peng, S.S.

2007-07-01

318

Friction and wear of metals with a single-crystal abrasive grit of silicon carbide: Effect of shear strength of metal  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with spherical, single-crystal silicon carbide riders in contact with various metals and with metal riders in contact with silicon carbide flats. Results indicate that: (1) the friction force in the plowing of metal and (2) the groove height (corresponding to the volume of the groove) are related to the shear strength of the metal. That is, they decrease linearly as the shear strength of the bulk metal increases. Grooves are formed in metals primarily from plastic deformation, with occasional metal removal. The relation between the groove width D and the load W can be expressed by W = kD, superscript n which satisfies Meyer's law.

Miyoshi, K.; Buckley, D. H.

1978-01-01

319

Applications of ERTS-1 data to landscape change in eastern Tennessee  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. The analysis of landscape change in eastern Tennessee from ERTS-1 data is being derived from three avenues of experimentation and analysis: (1) a multi-stage sampling procedure utilizing ground and aircraft imagery for ground truth and control; (2) a densitometric and computer analytical experiment for the analysis of gray tone signatures and comparisons for landscape change detection and monitoring; and (3) an ERTS image enhancement procedure for the detection and analysis of photomorphic regions. Significant results include: maps of strip mining changes and forest inventory, watershed identification and delimitation, and agricultural regions derived from spring plowing patterns appearing on the ERTS-1 imagery.

Rehder, J. B. (principal investigator)

1973-01-01

320

In the Footsteps of Charles Darwin: Patterns of Coastal Subsidence and Uplift Associated with Seamount Subduction, Basal Fore-arc Erosion and Seamount Accretion in Latin America  

NASA Astrophysics Data System (ADS)

In Geological Observations on South America (1846), Charles Darwin described beds of late Cenozoic marine seashells that were uplifted to elevations as much as several hundred meters above some localities on the western coastline of South America and implied that the whole coast was uplifting at geologic time scales. We know now that such evidence is generally restricted to coastal embayments above fore-arc basins where offshore seamounts are colliding with the South American fore arc (e.g., the Juan Fernandez seamount chain, Valpariso Basin and Valpariso Bay). We suggest that the phenomena of basal fore-arc erosion and basin formation and coastal uplift are closely related to effects of seamount subduction. Marine multibeam sonar images and multichannel seismic reflection surveys by others demonstrate that seamounts, although locally cut by normal faults in the outer-rise/near-trench region, initally subduct intact and the primary interaction with the toe of the fore arc is plowing, with material eroded from the fore arc that accumulates above and on the margins of the seamount. Submarine landslides above such regions over-steepened by plowing can lead to coastal embayments far upslope of the plowing. Such plowing interaction can therefore lead to the formation of large forearc basins and coastal embayments such as those at Valpariso, Chile, or narrow corridors of subsidence in the wake of subducting seamounts in Costa Rica. It is also known that the transition between interplate thrust seismicity, representing mechanical coupling between the plates, and aseismic slip occurs at depths of typically 30-60 km and often geographically near coastlines that mark the boundary between outer fore-arc subsidence and inner fore-arc uplift. We suggest that decoupling can occur at the base of seamounts (i.e., the originally sedimented seafloor on which the seamount lavas are laid down) and that such seamounts can be accreted to the fore arc above and lead to coastal uplift. Such basal decoupling is known to occur under active volcanic islands in the open ocean in connection with rifting and gravitational spreading, such as beneath the island of Hawaii. The spatial and temporal patterns of coastal uplift and subsidence on active margins can therefore record the local history of seamount subduction. This conceptual model explains the spatial patterns of offshore subsidence and coastal uplift in Chile and Costa Rica and also has implications for patterns of seismicity along the interplate thrust boundary.

Fisher, D. M.; Kirby, S. H.; David, S. W.

2004-12-01

321

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.

322

Black soldier fly (Diptera: Stratiomyidae) colonization of pig carrion in south Georgia.  

PubMed

The black soldier fly, Hermetia illucens (L.), is thought to colonize corpses 20-30 days postmortem. However, recent observations indicate this might not be true for all cases. Therefore, we conducted a study examining colonization by the black soldier fly and other Diptera on pig carrion in a plowed field in southern Georgia from 20 September through 21 February. Our data indicate black soldier flies could colonize a corpse within the first week after death. Knowing this information could prevent a serious mistake in estimating the time at which a corpse is colonized by this species. This study also represents the first record of Chrysomya rufifacies in Georgia. PMID:15831010

Tomberlin, Jeffery K; Sheppard, D Craig; Joyce, John A

2005-01-01

323

Waterfowl ecology and avian influenza in california: Do host traits inform us about viral occurrence?  

USGS Publications Warehouse

We examined whether host traits influenced the occurrence of avian influenza virus (AIV) in Anatidae (ducks, geese, swans) at wintering sites in California's Central Valley. In total, 3487 individuals were sampled at Sacramento National Wildlife Refuge and Conaway Ranch Duck Club during the hunting season of 2007-08. Of the 19 Anatidae species sampled, prevalence was highest in the northern shoveler (5.09%), followed by the ring-necked duck (2.63%), American wigeon (2.57%), bufflehead (2.50%), greater white-fronted goose (2.44%), and cinnamon teal (1.72%). Among host traits, density of lamellae (filtering plates) of dabbling ducks was significantly associated with AIV prevalence and the number of subtypes shed by the host, suggesting that feeding methods may influence exposure to viral particles. ?? 2010 American Association of Avian Pathologists.

Hill, N. J.; Takekawa, J. Y.; Cardona, C. J.; Ackerman, J. T.; Schultz, A. K.; Spragens, K. A.; Boyce, W. M.

2010-01-01

324

Foot preferences during resting in wildfowl and waders.  

PubMed

Footedness in birds has been reported, e.g., in parrots and chickens, but the direction of footedness remained unclear. Is a bird left-footed because it uses its left foot for holding and handling food, or is it right-footed because it uses the right foot for stabilisation and balancing while perching? In 2004 and 2006 I examined footedness in wildfowl and waders while the birds were performing a single task: roosting on the ground on one foot. Avocet (Recurvirostra avosetta), northern shoveller (Anas clypeata), oystercatcher (Haematopus ostralegus), and Eurasian curlew (Numenius arquata) were right-footed. Another 21 species did not show any significant foot preferences. This study provides some evidence that asymmetries in preferential foot use in birds may be triggered by a preference during postural control. PMID:17365634

Randler, Christoph

2007-03-01

325

Avian influenza in wild waterfowl and shorebirds in the Donana National Park: Serological survey using the enzyme-linked immunosorbent assay.  

PubMed

The indirect ELISA was used to detect antibodies to influenzavirus A in the sera of wildfowl from the Donana National Park. Of the 712 birds examined, 44 (6.2%) were seropositive. Positive birds belonged to 10 of the 13 species studied. Infection rates varied widely: spoonbill (Platalea leucorodia, 32.2%), mallard (Anas platyrhynchos, 9.9%), gadwall (Anas strepera, 8.6%), red-crested pochard (Netta rufina, 8.1%), pochard (Aythya ferina, 6.4%), shoveler (Anas clypeata, 5%), great crested grebe (Podiceps cristatus, 4.3%), avocet (Recurvirostra avosetta, 3.1%), grey heron (Ardea cinerea, 3.1%) and coot (Fulica atra, 0.8%). Although infection rates were not high, the wide range of avian species susceptible to influenzavirus A suggests circulation of the virus amongst wildfowl at Donana. PMID:18671098

Astorga, R J; Leon, L; Cubero, M J; Arenas, A; Maldonado, A; Tarradas, M C; Perea, A

1994-06-01

326

Mortality of waterfowl on a hypersaline wetland as a result of salt encrustation  

SciTech Connect

Approximately 300 geese, primarily lesser Canada geese (Branta canadensis parvipes) were found unable to fly or dead on a small hypersaline lake (conductivity 77,000-90,000 mumhos/cm) in western Saskatchewan in September 1985. The birds were heavily encrusted with sodium sulfate crystals. Dead birds that were necropsied had aspirated lake water and had evidence of acute muscle degeneration. The live geese (155) were captured and moved to nearby freshwater wetlands where most apparently survived. Some birds died of severe myopathy after translocation. Five northern shovelers (Anas clypeata) were found encrusted with salt and unable to fly on the lake approximately 10 days later. Salt encrustation apparently occurred when rapid cooling of the lake resulted in supersaturation and crystallization of the dissolved salt. A local resident recalled similar events occurring on the lake in autumn on at least two other occasions during the past 50 yr.

Wobeser, G.; Howard, J.

1987-01-01

327

Backcountry snowmobilers' risk perceptions, avalanche related information seeking behaviours, preparedness and decision-making processes  

NASA Astrophysics Data System (ADS)

Although there has been substantial research on the avoidance of risk, much less has been completed on voluntary risk. This study examined backcountry snowmobilers' risk perceptions, avalanche related information seeking behaviours, and decision-making processes when dealing with avalanches and backcountry risk in Canada. To accomplish this, in-depth, semi-structured interviews were conducted with 17 participants who were involved in backcountry snowmobiling. Interviews were done both in person and by telephone. The results of this study show that, unlike previous research on snowmobilers, the participants of this study were well prepared and knowledgeable about backcountry risks. All 17 participants stated that they carried a shovel, probe, and transceiver with them on each backcountry trip, and 10 participants had taken an avalanche safety course. Group dynamics and positive peer pressure were influential in promoting safe backcountry behaviour. KEYWORDS: Backcountry snowmobiling, Avalanches, Voluntary Risk, Preparedness, Decision-Making.

Baker, Jennifer

328

Deradiating the former uranium capital  

SciTech Connect

The city that once proclaimed itself The Uranium Capital of America is in the process of divorcing itself from the radioactive element - literally as well as symbolically. The last vestiges of uranium are being shoveled from the community. The removal is part of the federal Department of Energy's (DOE) Remedial Action program. It was established in 1972 to clean up areas of the country in which radiation exposure in excess of normal background levels could be attributed to wastes from DOE-operated uranium processing plants. Grand Junction was the first area to qualify. A good portion of the city is built on radioactive tailings - by-products of a uranium-processing industry. The DOE and the Environmental Protection Agency established guidelines for action levels of radiation. The standards were extrapolated from data from studies of lung cancer incidence in uranium miners in Europe and the US.

Merz, B.

1987-08-07

329

Maneuvering through a pipeline obstacle course  

SciTech Connect

Installing a pipeline may not seem like much of a challenge for natural gas companies, but the logistics of laying pipe in the ground is not simple in many cases, and no pipeline project is ever routine. Before lifting a shovel, there are a number of potential obstacles to consider: the possibility of damage to the environment and historical landmarks, the stress-resistance of the pipes themselves --- and, of course, the natural wonders of the world that are nothing less than holy terrors to the contractors who must work around, over and through them. It used to take six to eight months to build a pipeline; now it's one to two years just getting through FERC (the Federal Energy Regulatory Commission). This paper shows that with the right technology, as well as a little creativity, there's no hill too high, no field too fruitful, no ferret too feisty and no regulation too rigid to transport natural gas through pipelines anywhere, anyhow, anytime.

Gast, N.

1992-08-01

330

Physical work load in modern mining.  

PubMed

Following our Institute's involvement in the physiology of mining work (since 1953), this paper deals with underground work load investigated in terms of time, energy expenditure and heart rate in coal miners working with various types and degrees of mechanization. Results showed that a chamber coal face and at heading (coal or sterile rock) mechanization of haulage and loading (conveyor belt and loading machine) led to 50 -- 100 kcal reduction of energy expenditure/hour. At longwall faces, mechanization of haulage (by conveyor) or hewing and loading (with drum-combine) shortened shoveling time, while there was an increase of manual work in the tasks of supporting which was conducive to metabolic rates of 300 kcal/hour. In the case of fully mechanized coal working, including supporting, there was a significant decrease of energy expenditure. PMID:117467

Vaida, I; Pafnote, M

1979-01-01

331

Stone tool production and utilization by bonobo-chimpanzees (Pan paniscus).  

PubMed

Using direct percussion, language-competent bonobo-chimpanzees Kanzi and Pan-Banisha produced a significantly wider variety of flint tool types than hitherto reported, and used them task-specifically to break wooden logs or to dig underground for food retrieval. For log breaking, small flakes were rotated drill-like or used as scrapers, whereas thick cortical flakes were used as axes or wedges, leaving consistent wear patterns along the glued slits, the weakest areas of the log. For digging underground, a variety of modified stone tools, as well as unmodified flint nodules, were used as shovels. Such tool production and utilization competencies reported here in Pan indicate that present-day Pan exhibits Homo-like technological competencies. PMID:22912400

Roffman, Itai; Savage-Rumbaugh, Sue; Rubert-Pugh, Elizabeth; Ronen, Avraham; Nevo, Eviatar

2012-09-01

332

Part 1: Petrology and geochemistry of mafic and ultramafic xenoliths from the central Sierra Nevada batholith  

SciTech Connect

Two suites of mafic and ultramafic xenoliths occur in the Big Creek and Pick and Shovel volcanic pipes that cut the axial region of the Sierra Nevada batholith. One suite is composed of spinel and garnet bearing peridotites and westerites. The other suite consists dominantly of garnet clinopyroxenites with subordinate biotite ({plus minus}plagioclase) bearing garnet clinopyroxenites and biotite-free, plagioclase bearing garnet clinopyroxenites. Thermobarometric calculations indicate that they were derived from ca. 24-34 kbar. Thermobarometric calculations indicate that the P-T conditions of equilibration for the garnet clinopyroxenites range from 7 to 20 kbar and 600-800C. Rb-Sr, Sm-Nd, and U-Th-Pb isotopic systematics indicate that the age of this suite of xenoliths is approximately 220 Ma. This may imply that the garnet clinopyroxenites are basal cumulates of voluminous intrusions that give rise to the early Sierran granodiorites as residual liquids.

Mukhopadhyay, B.

1989-01-01

333

Mining in low coal. Volume 1. Biomechanics and work physiology. Open file report 15 Jun 78-15 Sep 81  

SciTech Connect

The objectives of this research were (1) to evaluate the job demands associated with low coal mining, (2) to survey the anthropometry, strength, and aerobic capacity of low coal miners to determine if they differ from the U.S. population, and (3) to recommend, on the basis of available information, optimal job and work station design for low coal mining. The male and female anthropometry, except for weight and circumferential dimensions, was quite similar to the comparison populations. Back strength for male and female miners was significantly lower than the industrial worker population. This can be one of the contributing factors of low back problems in mining. Shoveling, timbering, and helpers tasks were physiologically demanding activities. However, because of the frequent stoppage of work, adequate rest was usually available. If work stoppage is corrected, then better work and rest schedules are essential.

Ayoub, M.M.; Bethea, N.J.; Bobo, M.; Burford, C.L.; Caddel, D.K.

1981-11-01

334

Rhabdomyolysis and acute renal impairment in a patient with hypothyroidism: a case report.  

PubMed

We report the case of a 33-year-old male with hypothyroidism who developed acute renal impairment with rhabdomyolysis after strenuous physical activity (snow shoveling). His thyroid function test confirmed marked hypothyroidism. Severe elevation of serum CK consistent with rhabdomyolysis was noted and an elevated creatinine indicated acute renal impairment. Patient's condition improved significantly after starting him on thyroid hormone replacement therapy and aggressive hydration. Acute renal impairment with rhabdomyolysis in patients with hypothyroidism is quite rare and we expect that this case report adds to the existing literature on this subject. We also emphasize that thyroid status should be evaluated in patients with unexplained acute renal impairment and presenting with the symptoms of muscle involvement. PMID:24822067

Naz, Arshi; Issa, Mayada

2014-01-01

335

Rhabdomyolysis and Acute Renal Impairment in a Patient with Hypothyroidism: A Case Report  

PubMed Central

We report the case of a 33-year-old male with hypothyroidism who developed acute renal impairment with rhabdomyolysis after strenuous physical activity (snow shoveling). His thyroid function test confirmed marked hypothyroidism. Severe elevation of serum CK consistent with rhabdomyolysis was noted and an elevated creatinine indicated acute renal impairment. Patient's condition improved significantly after starting him on thyroid hormone replacement therapy and aggressive hydration. Acute renal impairment with rhabdomyolysis in patients with hypothyroidism is quite rare and we expect that this case report adds to the existing literature on this subject. We also emphasize that thyroid status should be evaluated in patients with unexplained acute renal impairment and presenting with the symptoms of muscle involvement.

Issa, Mayada

2014-01-01

336

Mountaintop converts to home sites  

SciTech Connect

A subsidiary of Filbert Imported Hardwoods is going to turn a mountaintop surface-mining operation into a 225 acre housing development after coal removal is completed. Located in western West Virginia, the plan developed by Architectural Assoc. of Charleston calls for investing about $8 million to construct 200 homes. Obtaining the necessary permits from the USBM Office of Surface Mining was difficult because of the law requiring restoration of surface mined land to approximate original contours. Special mining techniques of the four seams of metallurgical coal are described. A 1000 CK Poclain excavator is being tested on the excavation work at this site. The performance and cost guarantees of this hydraulic shovel are discussed.

Chironis, N.P.

1981-01-01

337

Maxillary and Mandibular First Premolars Showing Three-Cusp Pattern: An Unusual Presentation  

PubMed Central

Dental anatomy is the study of morphology of various teeth in human dentitions. The application of dental anatomy in clinical practice is important, and dentist should have a thorough knowledge regarding the morphology of the teeth. At times as a result of genetic variation, environmental factors, diet of an individual and race, variations in the morphology of the teeth can be observed. These variations have been extensively studied by the researcher in the field of anthropology to define a particular race. The most commonly observed changes include peg-shaped laterals, shovel-shaped incisors, and extra cusp on molar. Common variations documented with regard to maxillary and mandibular first premolars are the variation in the number of roots. But the variations with respect to crown morphology are few. We report a first documented unusual presentation of maxillary and mandibular first premolars with three-cusps pattern in a female patient.

Kotrashetti, Vijayalakshmi; Nayak, Aarati; Patil, Viraj; Kulkarni, Mayuri; Somannavar, Pradeep

2013-01-01

338

Geographical gradients in the population dynamics of North American prairie ducks.  

PubMed

1. Geographic gradients in population dynamics may occur because of spatial variation in resources that affect the deterministic components of the dynamics (i.e. carrying capacity, the specific growth rate at small densities or the strength of density regulation) or because of spatial variation in the effects of environmental stochasticity. To evaluate these, we used a hierarchical Bayesian approach to estimate parameters characterizing deterministic components and stochastic influences on population dynamics of eight species of ducks (mallard, northern pintail, blue-winged teal, gadwall, northern shoveler, American wigeon, canvasback and redhead (Anas platyrhynchos, A. acuta, A. discors, A. strepera, A. clypeata, A. americana, Aythya valisineria and Ay. americana, respectively) breeding in the North American prairies, and then tested whether these parameters varied latitudinally. 2. We also examined the influence of temporal variation in the availability of wetlands, spring temperature and winter precipitation on population dynamics to determine whether geographical gradients in population dynamics were related to large-scale variation in environmental effects. Population variability, as measured by the variance of the population fluctuations around the carrying capacity K, decreased with latitude for all species except canvasback. This decrease in population variability was caused by a combination of latitudinal gradients in the strength of density dependence, carrying capacity and process variance, for which details varied by species. 3. The effects of environmental covariates on population dynamics also varied latitudinally, particularly for mallard, northern pintail and northern shoveler. However, the proportion of the process variance explained by environmental covariates, with the exception of mallard, tended to be small. 4. Thus, geographical gradients in population dynamics of prairie ducks resulted from latitudinal gradients in both deterministic and stochastic components, and were likely influenced by spatial differences in the distribution of wetland types and shapes, agricultural practices and dispersal processes. 5. These results suggest that future management of these species could be improved by implementing harvest models that account explicitly for spatial variation in density effects and environmental stochasticity on population abundance. PMID:18631261

Saether, Bernt-Erik; Lillegård, Magnar; Grøtan, Vidar; Drever, Mark C; Engen, Steinar; Nudds, Thomas D; Podruzny, Kevin M

2008-09-01

339

Dust exposure during small-scale mining in Tanzania: a pilot study.  

PubMed

Small-scale mining in developing countries is generally labour-intensive and carried out with low levels of mechanization. In the Mererani area in the northern part of Tanzania, there are about 15000 underground miners who are constantly subjected to a poor working environment. Gemstones are found at depths down to 500 m. The objectives of this pilot study were to monitor the exposure to dust during work processes, which are typical of small-scale mining in developing countries, and to make a rough estimation of whether there is a risk of chronic pulmonary diseases for the workers. Personal sampling of respirable dust (n = 15) and 'total' dust (n = 5) was carried out during three consecutive days in one mine, which had a total of 50 workers in two shifts. Sampling started immediately before the miners entered the shaft, and lasted until they reappeared at the mine entrance after 5-8 h. The median crystalline silica content and the combustible content of the respirable dust samples were 14.2 and 5.5%, respectively. When drilling, blasting and shovelling were carried out, the exposure measurements showed high median levels of respirable dust (15.5 mg/m(3)), respirable crystalline silica (2.4 mg/m(3)), respirable combustible dust (1.5 mg/m(3)) and 'total' dust (28.4 mg/m(3)). When only shovelling and loading of sacks took place, the median exposures to respirable dust and respirable crystalline silica were 4.3 and 1.1 mg/m(3). This study shows that the exposure to respirable crystalline silica was high during underground small-scale mining. In the absence of personal protective equipment, the miners in the Mererani area are presumably at a high risk of developing chronic silicosis. PMID:12639837

Bratveit, Magne; Moen, Bente E; Mashalla, Yohana J S; Maalim, Hatua

2003-04-01

340

Deciduous dental morphology of the prehistoric Jomon people of Japan: comparison of nonmetric characters.  

PubMed

Morphological variations of the deciduous dentition are as useful as those of the permanent dentition for determining the biological affinities of human populations. This paper provides material on morphological variations of deciduous teeth of the prehistoric Japanese population from the Late and the Latest Jomon Period (ca. 2000-ca. 300 B.C.). The expression of nonmetric traits of the deciduous teeth in the Jomon sample shows a closer affinity with modern Japanese and Native American samples than with American White, Asiatic Indian, and African samples. However, the frequency of shoveling in deciduous upper incisors in the Jomon sample is lower than those in modern Japanese and Native American samples. The Jomon sample also expresses a much higher frequency of cusp 6 in deciduous lower second molars than seen in modern Japanese, Ainu, and Native American samples. The frequency in the Jomon sample is equal to that in the Australian Aboriginal sample, which shows cusp 6 most frequently among the samples compared. A somewhat low incidence of incisor shoveling in the Jomon sample was also reported in the permanent dentition (Turner [1976] Science 193:911-913, [1979] Am. J. Phys. Anthropol. 51:619-635, [1987] Am. J. Phys. Anthropol. 73:305-321, [1990] Am. J. Phys. Anthropol. 82:295-317; T. Hanihara [1992] Am. J. Phys. Anthropol. 88:163-182, 88:183-196). However, the frequency of cusp 6 in the Jomon sample shows no significant difference from those of Northeast Asian or Native American samples in the permanent dentition (Turner [1987] Am. J. Phys. Anthropol. 73:305-321; T. Hanihara [1992] Am. J. Phys. Anthropol. 88:163-182, 88:183-196). Evidently, some nonmetric traits express an inter-group difference only in the deciduous dentition. PMID:7653502

Kitagawa, Y; Manabe, Y; Oyamada, J; Rokutanda, A

1995-06-01

341

Organochlorine contaminants in California waterfowl  

USGS Publications Warehouse

Concern has been expressed that the extensive use of organochlorine pesticides in California may be exposing waterfowl to hazardous contaminant levels. The objectives of our study were to: (1) determine concentrations of organochlorines in northern pintails (Anas acuta) from five important waterfowl wintering areas in California; (2) compare concentrations of organochlorines in selected species with emphasis on relationships to their diets; and (3) determine the relationship between concentrations of organochlorines in wings and carcasses of pintails. In the 1980-81 hunting season, we obtained wings of pintails, canvasbacks (Aythya valisineria), and lesser scaups (A. affinis) from the Pacific Flyway survey of waterfowl productivity, and we collected additional pintails and northern shovelers (Anas clypeata) in the Sacramento Valley. Concentrations of all compounds in pintail wings were below 1 ppm (wet weight), but residues were higher in wings from pintails shot late in the hunting season than early in the season, suggesting that accumulation of chemicals occurs while ducks are wintering in California. Highest concentrations were found in pintails from the southern regions and lowest in those from the northern regions of the state. DDE was significantly higher in males than in females. Wings of diving ducks were too few to enable statistical comparisons. Carcasses of shovelers contained residues of a wide array of organochlorines and significantly (P < 0.001) higher mean concentrations of DDE (0.68 ppm) than did pintails (0.12 ppm) collected at the same time and place. On a wet-weight basis, concentrations of DDE and DDT in the wings of pintails were about half those in the carcasses. Overall, concentrations of organochlorines were relatively low in all species and probably would have no effect on population survival or reproduction. However, some individuals contained elevated and possibly harmful levels of certain chemicals.

Ohlendorf, H. M.; Miller, M. R.

1984-01-01

342

Modified pre-curved patellar basket plate, reconstruction of the proper length and position of the patellar ligament--a biomechanical analysis.  

PubMed

Biomechanical properties of basket plate fixation for fracture dislocation in the distal part of the patella were studied on 22 fresh-frozen lower extremities (human cadaveric knees). The patella and the patellar ligament with the proximal tibia were removed. A comminuted fracture of the distal part of the patella was created with a chisel. The fractured patella, patellar ligament and tibial tuberosity of each specimen were fixed with a basket plate and mounted into the jaws of the testing machine. The measured load to failure was 421.66+/-45.90 N, which is approximately 70% higher than the results in other studies. The results of the measurements verified the results of finite element analysis. The modified precurved patellar basket plate developed in this study showed improved performance compared to the pre-existing fixation methods. PMID:17433694

Krkovic, M; Bombac, D; Balazic, M; Kosel, F; Hribernik, M; Senekovic, V; Brojan, M

2007-06-01

343

Lorenz Heister's handbook of surgery in the Franciscan monastery in Pazin.  

PubMed

The oldest library in Istria (Croatia) is located in the Franciscan Monastery of Pazin, with a rich fund of worthy old books. Our attention was attracted by the book "Chirurgie" written by the German physician, surgeon and anatomist Lorenz Heister in the first half of the 18th century. This worthy book is relatively scanty known in Croatian history of surgery. By studying the contents of the book written in the 18th century, numerous surgical instruments, as well as surgical operations may be found, many of them being used even today with little modifications. Among the instruments different types of pincers, needles, scissors, knives, saws, hammers, chisels and others can be found. The description of different surgical procedures reveals great advancement in the surgical technique. The book was very popular in Europe for a century. PMID:24496369

Tomi?, Danijela; Laginja, Stanislava

2014-02-01

344

Feature length-scale modeling of LPCVD & PECVD MEMS fabrication processes.  

SciTech Connect

The surface micromachining processes used to manufacture MEMS devices and integrated circuits transpire at such small length scales and are sufficiently complex that a theoretical analysis of them is particularly inviting. Under development at Sandia National Laboratories (SNL) is Chemically Induced Surface Evolution with Level Sets (ChISELS), a level-set based feature-scale modeler of such processes. The theoretical models used, a description of the software and some example results are presented here. The focus to date has been of low-pressure and plasma enhanced chemical vapor deposition (low-pressure chemical vapor deposition, LPCVD and PECVD) processes. Both are employed in SNLs SUMMiT V technology. Examples of step coverage of SiO{sub 2} into a trench by each of the LPCVD and PECVD process are presented.

Plimpton, Steven James; Schmidt, Rodney Cannon; Musson, Lawrence Cale; Ho, Pauline (Reaction Design, Inc., San Diego, CA)

2004-06-01

345

A balsa violin  

NASA Astrophysics Data System (ADS)

Almost half a century ago John Schelleng determined the scaling rules that show how violins can be made from nontraditional materials. These principles suggest that balsa wood may be a possible, if unlikely, construction material. To test this idea, a balsa violin was constructed and found to be playable. Its vibrational behavior is shown to be in agreement with Schelleng's scaling rules. The instrument was not difficult to build, and its construction can be repeated by anyone of moderate skill with a chisel and sandpaper and access to an audio frequency analysis program. The reward is a tactile appreciation for the vibrational behavior of materials and the physics of musical instruments that is difficult to gain otherwise.

Waltham, Chris

2009-01-01

346

Were Viking Dry-dock methods in the Americas used earlier to Build Pyramids, with Outflow Eroding the Sphinx, and were Stonehenge, the Obelisks, and Moas Similarly Erected?  

NASA Astrophysics Data System (ADS)

Chisel-quarried recycled granite in MA is datable by runes to 1069 CE; it could corroborate dating by a LIDAR. Associated sites, possibly used by Vikings to dry-dock their ships, could have exploited lock-like controls, possibly a continued technology. Site-leveling at the Giza Pyramids proves water was used. `Locks' and body-immersion worked for building, moving, erecting, or watering, at sites like Stonehenge, The Hanging Gardens at Babylon, the Moas of Easter Island, or The Pyramids, where the eroding water discharge was deliberately flushed over the Sphinx complex. It enhance the electromagnetically excited blue light signals we can detect, especially at sites frequented by Molocket of ME. Information, as at America's Stonehenge, in NH, and constructions at Acton MA, at Giza or at Rumford ME proves that the Pyramids and Sphinx were engineered and built about 4500 BP.

McLeod, Edward; McLeod, Roger

2006-03-01

347

So I Sat Down with My Mother: Connectedness Orientation and Pupils' Independence  

NASA Astrophysics Data System (ADS)

Swedish educational policy underlines the importance of independence. In this paper we use socio-cultural theory and Foucault to explain how pupils’ independency is transformed into something else in their work. Our results derive from analyses of filmed sessions and entries in the pupils’ logbooks. Our findings demonstrate that the pupils’ definitions of independence differ from those of the course plan in several aspects: i) the use of certain resources is not considered to show lack of independence, ii) doing things yourself is considered being most independent and iii) to follow instructions, even if this means violating your unique personal thought, is considered a prerequisite for passing/getting good grades and as such a necessary adaption to the school context, sooner than a sign of dependency. Consequently we argue that pupil independency should be regarded as a phenomenon chiseled out within a community of practice rather than a personal capacity.

Eklöf, Anders; Nilsson, Lars-Erik; Svensson, Peter

348

Benchmarks for target tracking  

NASA Astrophysics Data System (ADS)

The term benchmark originates from the chiseled horizontal marks that surveyors made, into which an angle-iron could be placed to bracket ("bench") a leveling rod, thus ensuring that the leveling rod can be repositioned in exactly the same place in the future. A benchmark in computer terms is the result of running a computer program, or a set of programs, in order to assess the relative performance of an object by running a number of standard tests and trials against it. This paper will discuss the history of simulation benchmarks that are being used by multiple branches of the military and agencies of the US government. These benchmarks range from missile defense applications to chemical biological situations. Typically, a benchmark is used with Monte Carlo runs in order to tease out how algorithms deal with variability and the range of possible inputs. We will also describe problems that can be solved by a benchmark.

Dunham, Darin T.; West, Philip D.

2011-09-01

349

X-Ray Fluorescence and Laser-Induced Breakdown Spectroscopy analysis of Roman silver denarii  

NASA Astrophysics Data System (ADS)

In this paper we present the results of a study performed on a large collection of silver Roman republican denarii, encompassing about two centuries of history. The joint use of Laser-Induced Breakdown Spectroscopy (LIBS) and X-Ray Fluorescence (XRF) spectroscopy allowed for an accurate determination of the coins' elemental composition; the measurements, performed mostly in situ at the 'Monetiere' in Florence, revealed a striking connection between the 'quality' of the silver alloy and some crucial contemporary events. This finding was used to classify a group of denarii whose dating was otherwise impossible. The comparison with other contemporary denarii disproves a recent theory on the origin of the so called 'serrated' denarii (denarii showing notched chisel marks on the edge of the coin).

Pardini, L.; El Hassan, A.; Ferretti, M.; Foresta, A.; Legnaioli, S.; Lorenzetti, G.; Nebbia, E.; Catalli, F.; Harith, M. A.; Diaz Pace, D.; Anabitarte Garcia, F.; Scuotto, M.; Palleschi, V.

2012-08-01

350

Late Bronze Age hoard studied by PIXE  

NASA Astrophysics Data System (ADS)

The hoards of metallic objects belonging to the Late European Bronze Age can be interpreted differently depending on the type, number and composition of the artefacts. PIXE analysis has been performed in nine items from the Hoard of Freixanda in Portugal comprising four socket axes, a palstave axe, a ring, a chisel, a dagger, and a casting debris. Besides the composition of the main matrix elements, that is Cu and Sn, the amount of trace elements of interest like, As, Pb, Ni, and Ag has been determined using this ion beam technique. The high tin content alloy and the high purity of the metals from the Freixanda hoard are characteristic of the Portuguese and Spanish Late Bronze Age metallurgy, supporting the idea of a regional production.

Gutiérrez Neira, P. C.; Zucchiatti, A.; Montero-Ruiz, I.; Vilaça, R.; Bottaini, C.; Gener, M.; Climent-Font, A.

2011-12-01

351

A study of hand vibration on chipping and grinding operators, part III: Power levels into the hands of operators of pneumatic tools used in chipping and grinding operations  

NASA Astrophysics Data System (ADS)

This paper presents a method for calculating power transmitted to the hands of operators who use vibrating hand tools. Results that relate to a comprehensive multidisciplined NIOSH field study of several hundred chipper and grinder workers who used pneumatic hand tools are presented. The results of this study indicated that the power in the frequency range of 6·3 Hz to 1000 Hz transmitted to the hand ranged from 1·08 × 10 3 to 7·23 × 10 3 J/s for the chisel and from 8·52 × 10 -1 to 1·57 × 10 2 J/s for the handle of chipping hammers. For pneumatic grinders the power transmitted to the hands of the tool operators was in the range of 6·58 × 10 -3 to 2·35 × 10 -3 J/s over the same frequency range.

Reynolds, D. D.; Basel, R.; Wasserman, D. E.; Taylor, W.

1984-08-01

352

Experimental determination of scanning probe microscope cantilever spring constants utilizing a nanoindentation apparatus  

NASA Astrophysics Data System (ADS)

A rapid, nondestructive, and accurate method for determining the normal spring constants of scanning probe microscopy cantilevers is presented. Spring constants are determined using a commercial combination atomic force microscope and nanoindentation apparatus configured with a W-indenter tip geometrically configured into either a scanning tunneling microscope pointed tip or chisel shape that may be placed onto the cantilever of interest with high accuracy. A load is applied to the cantilever tip and the corresponding displacement is measured. From the force-displacement curve, the spring constant is determined. For cantilevers with spring constants greater than 1 N/m, the derived spring constants are believed to be accurate to within +/-10%, with better accuracy for stiffer levers. This method has been used to measure the stiffness of cantilevers from several manufacturers.

Holbery, J. D.; Eden, V. L.; Sarikaya, M.; Fisher, R. M.

2000-10-01

353

Pseudopillow fracture systems in lavas: Insights into cooling mechanisms and environments from lava flow fractures  

NASA Astrophysics Data System (ADS)

Detailed field observations of structures within the flow front of a Holocene trachyandesite lava from Snæfellsnes, Iceland, are presented. The lava provides exceptional three-dimensional exposure of complex brittle and ductile deformation textures that record processes of lava fracture and quenching driven by external water. The flow front interior is characterised by structures consisting of a large (metre-scale) curviplanar master fracture with many smaller (centimetre-scale) subsidiary fractures perpendicular to the master fracture. Such structures have previously been recognised in a range of lava compositions from basalt to dacite and called pseudopillows or pseudopillow fractures. We propose the term pseudopillow fracture systems to emphasise the consistent package of different fracture types occurring together. All documented occurrences of pseudopillow fracture systems are in lavas that have been inferred to interact with an aqueous coolant (i.e. liquid water, ice or snow). We use fracture surface textures and their orientation in relation to flow banding to identify three distinct types of master fracture and two types of subsidiary fractures. Master fracture surface textures used to identify fracture mechanisms include chisel marks (striae), cavitation dimples, river lines and rough/smooth fracture surface textures. These indicate both brittle and ductile fracture happening on different types of master fracture. Chisel marks on subsidiary fractures indicate comparative cooling rates, cooling directions and isotherm orientations at the time of fracture. We propose a model for pseudopillow fracture system formation taking into account all the various fracture types, textures and fracture propagation mechanisms and discuss their implications for interaction mechanisms between lava flows and external coolants.

Forbes, A. E. S.; Blake, S.; McGarvie, D. W.; Tuffen, H.

2012-11-01

354

Shadow analysis of soil surface roughness compared to the chain set method and direct measurement of micro-relief  

NASA Astrophysics Data System (ADS)

Soil surface roughness (SSR) is an excellent indicator of soil susceptibility to wind and water erosion and plays an important role in the development and the maintenance of soil biota. Several methods have been developed to characterise SSR based on different methods of acquiring data. Because the main problems related to these methods involve the use and handling of equipment in the field, the present study aims to fill the need for a method for measuring SSR that is more reliable, low-cost and convenient in the field than traditional field methods. Shadow analysis, which interprets micro-topographic shadows, is based on the principle that there is a direct relationship between the soil surface roughness and the shadows cast by soil structures under fixed sunlight conditions. SSR was calculated with shadows analysis in the laboratory using hemispheres of different diameter with a diverse distribution of known altitudes and a surface area of 1 m2. Data obtained from the shadow analysis were compared to data obtained with the chain method and simulation of the micro-relief. The results show a relationship among the SSR calculated using the different methods. To further improve the method, shadow analysis was used to measure the SSR in a sandy clay loam field using different tillage tools (chisel, tiller and roller) and in a control of 4 m2 surface plots divided into subplots of 1 m2. The measurements were compared to the data obtained using the chain set and pin meter methods. The SSR measured was the highest when the chisel was used, followed by the tiller and the roller, and finally the control, for each of the three methods. Shadow analysis is shown to be a reliable method that does not disturb the measured surface, is easy to handle and analyse, and shortens the time involved in field operations by a factor ranging from 4 to 20 compared to well known techniques such as the chain set and pin meter methods.

García Moreno, R.; Díaz Álvarez, M. C.; Tarquis, A. M.; Paz González, A.; Saa Requejo, A.

2010-02-01

355

Shadow analysis of soil surface roughness compared to the chain set method and direct measurement of micro-relief  

NASA Astrophysics Data System (ADS)

Soil surface roughness (SSR) expresses soil susceptibility to wind and water erosion and plays an important role in the development and the maintenance of soil biota. Several methods have been developed to characterise SSR based on different methods of acquiring data. Because the main problems related to these methods involve the use and handling of equipment in the field, the present study aims to fill the need for a method for measuring SSR that is more reliable, low-cost and convenient in the field than traditional field methods. Shadow analysis, which interprets micro-topographic shadows, is based on the principle that there is a direct relationship between the soil surface roughness and the shadows cast by soil structures under fixed sunlight conditions. SSR was calculated with shadows analysis in the laboratory using hemispheres of different diameter with a diverse distribution of known altitudes and a surface area of 1 m2. Data obtained from the shadow analysis were compared to data obtained with the chain method and simulation of the micro-relief. The results show a relationship among the SSR calculated using the different methods. To further improve the method, shadow analysis was used to measure the SSR in a sandy clay loam field using different tillage tools (chisel, tiller and roller) and in a control of 4 m2 surface plots divided into subplots of 1 m2. The measurements were compared to the data obtained using the chain set and pin meter methods. The SSR measured was the highest when the chisel was used, followed by the tiller and the roller, and finally the control, for each of the three methods. Shadow analysis is shown to be a reliable method that does not disturb the measured surface, is easy to handle and analyse, and shortens the time involved in field operations by a factor ranging from 4 to 20 compared to well known techniques such as the chain set and pin meter methods.

García Moreno, R.; Díaz Álvarez, M. C.; Tarquis, A. M.; Paz González, A.; Saa Requejo, A.

2010-08-01

356

Experimental evidence that human impacts drive fire ant invasions and ecological change  

PubMed Central

Biological invasions are often closely associated with human impacts and it is difficult to determine whether either or both are responsible for the negative impacts on native communities. Here, we show that human activity, not biological invasion, is the primary driver of negative effects on native communities and of the process of invasion itself. In a large-scale experiment, we combined additions of the exotic fire ant, Solenopsis invicta, with 2 disturbance treatments, mowing and plowing, in a fully crossed factorial design. Results indicate that plowing, in the absence of fire ants, greatly diminished total native ant abundance and diversity, whereas fire ants, even in the absence of disturbance, diminished some, but not all, native ant abundance and diversity. Transplanted fire ant colonies were favored by disturbance. In the absence of disturbance and on their own, fire ants do not invade the forest habitats of native ants. Our results demonstrate that fire ants are “passengers” rather than “drivers” of ecological change. We propose that fire ants may be representative of other invasive species that would be better described as disturbance specialists. Current pest management and conservation strategies should be reassessed to better account for the central role of human impacts in the process of biological invasion.

King, Joshua R.; Tschinkel, Walter R.

2008-01-01

357

Effects of "open burning" on the greenhouse gas exchange from a single-rice paddy field in Japan  

NASA Astrophysics Data System (ADS)

Paddy fields are artificially maintained wetland and are one of the large source of CH4. Besides, a large quantity of N2O is emitted from the soil surface due to the decomposition of inorganic fertilizer. A long term continuous measurement of GHG fluxes between atmosphere and paddy ecosystem is effective method to clarify the contribution of paddy fields to recent rapid increase of GHG concentration. In this study, three techniques for flux measurement (eddy covariance, aerodynamic gradient, and chamber techniques) were applied to investigate the annual variation of three GHG (CO2, CH4 and N2O) exchanges at a single-rice paddy field for two years. An observational site is located on reclaimed land in the southern part of Okayama Prefecture, Japan. In addition, an experimental paddy field was divided into two areas to investigate what impact is brought on the annual GHG fluxes by the difference of disposal management of residual biomass after the harvest. Residual biomass was burned and plowed into soil at the one area on Nov. 29th, 2011, and residue was not burned and directly plowed into soil at the other area as usual. We illustrate some results for the control term before the burning experiment, and for the comparison term after the experiment.

Kawamoto, Y.; Akaike, Y.; Kunishio, A.; Murakami, H.; Ono, K.; Hayashi, K.; Iwata, T.

2012-12-01

358

Effects of residual biomass burning on the CO2 flux from a paddy field  

NASA Astrophysics Data System (ADS)

Paddy field is one of the most important eco-system in monsoon Asia, and takes a great important role in CO2 uptake. Carbon budget in agricultural field is influenced by some artificial management. After the harvest, residual biomass is burned on fields, brought out from fields, or remained and harrowed into the fields. If open burning was conducted in a field, one part of biomass carbon is emitted into atmosphere as CO2, and the other part is harrowed into soils. In this study, quantity of lost carbon according to burning of residual biomass were investigated at a single rice cropping field in western Japan, in which long-term continuous CO2 flux (NEE) measurement by the eddy-covariance technique was conducted. In addition, an experimental paddy field was divided into two areas to investigate what impact is brought on the annual CO2 flux by the difference of disposal management of residual biomass after the harvest. Residual biomass was burned and plowed into soil at the one area on Nov. 29th, 2011, and residue was not burned and directly plowed into soil at the other area as usual. We illustrate some results for the control term before the burning experiment, and for the comparison term after the experiment.

Murakami, H.; Kunishio, A.; Akaike, Y.; Kawamoto, Y.; Ono, K.; Iwata, T.

2012-12-01

359

Removal of coagulant aluminum from water treatment residuals by acid.  

PubMed

Sediment sludge during coagulation and sedimentation in drinking water treatment is called "water treatment residuals (WTR)". Polyaluminum chloride (PAC) is mainly used as a coagulant in Japan. The recycling of WTR has been desired; one method for its reuse is as plowed soil. However, WTR reuse in this way is inhibited by the aluminum from the added PAC, because of its high adsorption capacity for phosphate and other fertilizer components. The removal of such aluminum from WTR would therefore be advantageous for its reuse as plowed soil; this research clarified the effect of acid washing on aluminum removal from WTR and on plant growth in the treated soil. The percentage of aluminum removal from raw WTR by sulphuric acid solution was around 90% at pH 3, the percentage decreasing to 40% in the case of a sun-dried sample. The maximum phosphate adsorption capacity was decreased and the available phosphorus was increased by acid washing, with 90% of aluminum removal. The enhancement of Japanese mustard spinach growth and the increased in plant uptake of phosphates following acid washing were observed. PMID:24835954

Okuda, Tetsuji; Nishijima, Wataru; Sugimoto, Mayo; Saka, Naoyuki; Nakai, Satoshi; Tanabe, Kazuyasu; Ito, Junki; Takenaka, Kenji; Okada, Mitsumasa

2014-09-01

360

Nanoscale contact mechanics of biocompatible polyzwitterionic brushes.  

PubMed

Friction force microscopy has been used to demonstrate that biocompatible, lubricious poly(2-(methacryloyloxy)ethylphosphorylcholine) (PMPC) brushes exhibit different frictional properties depending on the medium (methanol, ethanol, 2-propanol, and water; the latter also with different quantities of added salt). The chemical functionalization of the probe (amine-, carboxylic acid-, and methyl-terminated probes were used) is not as important as the medium in determining the contact mechanics. For solvents such as methanol, where the adhesion between AFM probe and PMPC brushes is negligible, a linear friction-load relationship is observed. In contrast, the friction-load plot is nonlinear in ethanol or water, media in which stronger adhesion is measured. For ethanol, the data indicate Johnson-Kendall-Roberts (JKR) mechanics, whereas the Derjaguin-Muller-Toporov (DMT) model provided a good fit for the data acquired in water. Contact mechanics on zwitterionic PMPC brushes immersed in aqueous solutions of varying ionic strength followed the same trend, with high adhesion energies being correlated with a nonlinear friction-load relationship. These results can be rationalized by treating the friction force as the sum of a load-dependent term, attributed to molecular plowing, and an area-dependent shear term. In a good solvent for PMPC such as methanol, the shear term is negligible and the sliding interaction is dominated by molecular plowing. However, the adhesion energy is significantly larger in water and ethanol and the shear term is no longer negligible. PMID:23855771

Zhang, Zhenyu; Morse, Andrew J; Armes, Steven P; Lewis, Andrew L; Geoghegan, Mark; Leggett, Graham J

2013-08-27

361

Fatty acid composition of adipose tissue triglycerides after weight loss and weight maintenance: the DIOGENES study.  

PubMed

Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors. PMID:23098653

Kunešová, M; Hlavatý, P; Tvrzická, E; Sta?ková, B; Kalousková, P; Viguerie, N; Larsen, T M; van Baak, M A; Jebb, S A; Martinez, J A; Pfeiffer, A F H; Kafatos, A; Handjieva-Darlenska, T; Hill, M; Langin, D; Zák, A; Astrup, A; Saris, W H M

2012-01-01

362

Fatty Acid Composition of Adipose Tissue Triglycerides After Weight Loss and Weight Maintenance: the DIOGENES Study  

PubMed Central

Summary Fatty acid composition of adipose tissue changes with weight loss. Palmitoleic acid as a possible marker of endogenous lipogenesis or its functions as a lipokine are under debate. Objective was to assess the predictive role of adipose triglycerides fatty acids in weight maintenance in participants of the DIOGENES dietary intervention study. After an 8-week low calorie diet (LCD) subjects with > 8 % weight loss were randomized to 5 ad libitum weight maintenance diets for 6 months: low protein (P)/low glycemic index (GI) (LP/LGI), low P/high GI (LP/HGI), high P/low GI (HP/LGI), high P/high GI (HP/HGI), and a control diet. Fatty acid composition in adipose tissue triglycerides was determined by gas chromatography in 195 subjects before the LCD (baseline), after LCD and weight maintenance. Weight change after the maintenance phase was positively correlated with baseline adipose palmitoleic (16:1n-7), myristoleic (14:1n-5) and trans-palmitoleic acid (16:1n-7t). Negative correlation was found with baseline oleic acid (18:1n-9). Lower baseline monounsaturated fatty acids (14:1n-5, 16:1n-7 and trans 16:1n-7) in adipose tissue triglycerides predict better weight maintenance. Lower oleic acid predicts lower weight decrease. These findings suggest a specific role of monounsaturated fatty acids in weight management and as weight change predictors.

KUNESOVA, M.; HLAVATY, P.; TVRZICKA, E.; STANKOVA, B.; KALOUSKOVA, P.; VIGUERIE, N.; LARSEN, T. M.; VAN BAAK, M. A.; JEBB, S. A.; MARTINEZ, J. A.; PFEIFFER, A. F. H.; KAFATOS, A.; HANDJIEVA-DARLENSKA, T.; HILL, M.; LANGIN, D.; ZAK, A.; ASTRUP, A.; SARIS, W. H. M.

2013-01-01

363

The Effect of surface morphology on the friction of Electrogalvanized sheet steel in forming processes  

SciTech Connect

The effect in the drawbead simulator test were evaluated for a set of commercially coated steels and a set of laboratory coated steels with underlying surfaces produced by laser textured, shot blast, and electro-discharge textured rolls. In general, surfaces with higher roughness (R{sub a} parameter) measured lower friction in the DBS tests. The requisite roughness amplitude necessary for low friction was moderated somewhat by having a more closely spaced roughness as described by the median wavelength, {lambda}m, of the power spectrum. This effect is due to interaction with the lubricant by the micro-roughness imparted by the galvanizing process. The lubricant tends to be retained better by the surfaces with the micro-roughness, thereby increasing the amount of elasto- and plasto-hydrodynamic support of the load. Other variables, such as large variations in thickness of the sheet can mask the effect of the surface by changing the actual distance of sliding contact during the DBS test. For tests where the amount of sliding is similar, the effect of roughness is significant. The friction measured for EG steels in the DBS test is dominated by deformation of the surface with plowing by the asperities of the tooling adding to that caused by the deformation. The size of the plow marks in the deformed surfaces corresponds to the roughness of the tooling and no significant evidence of wear particles was observed.

Skarpelos, P.N. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

1993-12-01

364

Variation Of Soil Moisture Patterns In Response To Anthropogenic Land Disturbances In A Semiarid Regional Landscape  

NASA Astrophysics Data System (ADS)

This project focuses on examination of the effects of various land management practices on soil moisture for semiarid regional landscapes. The project is at the Wellhausen Ranch Research Station located near Laredo, TX. This ranch has undergone various land disturbances such as root plowing and cattle overgrazing that have caused damage to the vegetation and natural communities. Two research sites were chosen within the ranch, one disturbed by root plowing and one undisturbed, to represent various land use environment. Soil moisture analysis was performed, using the WatchDog Irrigation System, to identify the effects of temperature, vegetation, diurnal, and seasonal effect on the soil moisture patterns. In addition, three soil moisture probes were placed on the same location at three different depths, 3, 5, and 8 inches, below the surface, to evaluate the soil moisture profile in vertical direction. Statistical analysis such as ANOVA, Friedman's test, and the sign test was conducted and the results suggested that soil moisture is influenced by land disturbances significantly in a semiarid regional landscape.

Camarena, C.; Ren, J.; Jones, K.; Hempel, A.

2005-12-01

365

[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

366

Specific features of bacterial communities in floodplain agrocenoses  

NASA Astrophysics Data System (ADS)

The analysis of the taxonomic structure of the bacterial complexes in the alluvial soils of the Oka River valley allowed revealing the distinct differences in the spectrum of the bacterial dominants in the virgin and cultivated soils. Arthrobacter and pigment coryneform bacteria are shown to predominate in the virgin soil; bacilli and pseudomonades are common in the soil under vegetables. On cabbage leaves and carrot roots (both healthy and rotten), the spectrum of dominants is composed of two genera of enterobacteria: Pantoea and Erwinia. As a result of the plowing in of vegetables into the soil, enterobacteria accumulate; among them, phytopathogenic species are present. Within a year after this plowing in and the new yield, the enterobacteria practically disappeared, but myxobacteria and cytophages developed. Since these bacteria belong to the cellulose-destroying prokaryotes, the increase in their contents in the soil testified to their participation in the decomposition of the buried vegetable residues. Weeds are known to concentrate various bacterial forms in the phylloplane; they enter from different ecological niches: soil, water, meadow, and agricultural plants. Representatives of phytopathogenic bacteria as minor components were found on weeds.

Dobrovol'Skaya, T. G.; Leont'evskaya, E. A.; Sneg, A. A.; Balabko, P. N.

2010-04-01

367

Geographic applications of ERTS-1 imagery to landscape change. [Mississippi River and Great Smoky Mountains of Tennessee and North Carolina  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. ERTS-1 has proven to be an effective earth-orbiting monitor of landscape change. Its regional coverage for large areal monitoring has been effective for the detection and mapping of agricultural plowing regions, for general forest cover mapping, for flood mapping, for strip mine mapping, and for short-lived precipitation mapping patterns. Paramount to the entire study has been the temporal coverage provided by ERTS. Without the cyclic coverage on an 18 day basis, temporal coverage would have been inadequate for the detection and mapping of strip mining landscape change, the analysis of agricultural landscape change based on plowing patterns, the analysis of urban-suburban growth changes, and the mapping of the Mississippi River floods. Cost benefits from ERTS are unquestionably superior to aircraft systems in regard to large regional coverage and cyclic temporal parameters. For the analysis of landscape change in large regions such as statewide areas or even areas of 10,000 square miles, ERTS is of cost benefit consideration. Not only does the cost of imagery favor ERTS but the reduction of man-hours using ERTS has been in the magnitude of 1:10.

Rehder, J. B. (principal investigator)

1973-01-01

368

Downhill turn techniques and associated physical characteristics in cross-country skiers.  

PubMed

Three dominant techniques are used for downhill turning in cross-country skiing. In this study, kinematic, kinetic, and temporal characteristics of these techniques are described and related to skier strength and power. Twelve elite female cross-country skiers performed six consecutive turns of standardized geometry while being monitored by a Global Navigation Satellite System. Overall time was used as an indicator of performance. Skiing and turning parameters were determined from skier trajectories; the proportional use of each technique was determined from video analysis. Leg strength and power were determined by isometric squats and countermovement jumps on a force plate. Snow plowing, parallel skidding, and step turning were utilized for all turns. Faster skiers employed less snow plowing and more step turning, more rapid deceleration and earlier initiation of step turning at higher speed (r?=?0.80-0.93; all P?

Bucher Sandbakk, S; Supej, M; Sandbakk, O; Holmberg, H-C

2013-03-20

369

Biochar reduces short-term nitrate leaching from a horizon in an apple orchard.  

PubMed

Nitrogen leaching in croplands is a worldwide problem with implications both on human health and on the environment. Efforts should be taken to increase nutrient use efficiency and minimize N losses from terrestrial to water ecosystems. Soil-applied biochar has been reported to increase soil fertility and decrease nutrient leaching in tropical soils and under laboratory conditions. Our objective was to evaluate the effect of biochar addition on short-term N leaching from A soil horizon in a mature apple orchard growing on subalkaline soils located in the Po Valley (Italy). In spring 2009, 10 Mg of biochar per hectare was incorporated into the surface 20-cm soil layer by soil plowing. Cumulative nitrate (NO) and ammonium (NH) leaching was measured in treated and control plots 4 mo after the addition of biochar and the following year by using ion-exchange resin lysimeters installed below the plowed soil layer. Cumulative NO leaching was not affected by biochar after 4 mo, whereas in the following year it was significantly ( < 0.05) reduced by 75% over the control (from 5.5 to 1.4 kg ha). Conversely, NH leaching was very low and unaffected by soil biochar treatment. The present study shows that soil biochar addition can significantly decrease short-term nitrate leaching from the surface layer of a subalkaline soil under temperate climatic conditions. PMID:23673741

Ventura, M; Sorrenti, G; Panzacchi, P; George, E; Tonon, G

2013-01-01

370

Soil Carbon Chronosequences From Post-Agricultural Land in Western New England.  

NASA Astrophysics Data System (ADS)

We used quantitatively excavated soil pits to sample chronosequences of post-agricultural northern hardwood forest soils in the Hopkins Memorial Forest, Williamstown, MA, to determine how much carbon was lost during the period of agricultural use, and the rates at which C accumulated after abandonment. We developed chronosequences (based on the time of abandonment) for the three main agricultural uses--cultivated cropland, pasture or hay, and woodlot. Active farms served as our theoretical zero time points and old-growth stands in the region served as the likely maximum. Our data show a significant direct relationship between time since abandonment and carbon amount for the organic horizons (Oe and Oa) of plots that were cultivated, hayed or pastured, but not for stands that were formerly woodlots. There was likewise a significant direct relationship between C content and time for the plowed horizons (0-10 cm) of cultivated ground, but not for the top 10 cm of mineral soils that were formerly in hay/pasture or woodlot. Our best estimates suggest that cultivation reduced the C content of plowed soils by 50% to a depth of 10 cm, and that complete recovery of the soil C pool requires about 120 years.

Clark, J. D.; Johnson, A. H.; Richter, S.; Art, H. W.

2007-12-01

371

Learned appetites for calcium, phosphorus, and sodium in sheep.  

PubMed

If supplemental minerals are needed to promote optimal animal performance, what is the best way of providing them: free choice or in the diet? We hypothesized that herbivores discriminate among feeds containing Na, P, and Ca and modify their choices as a function of need. One group of lambs was fed a basal diet low in P and high in Ca (low P-high Ca), whereas another group was fed a basal diet high in P and low in Ca (high P-low Ca). After 73 d of exposure to the unbalanced diets, the lambs were conditioned by offering flavored grape pomace containing NaCl, CaCO(3), or NaH(2)PO(4). Preference for pomace + minerals was determined when all lambs were fed a basal diet of alfalfa pellets and barley grain (initial preference) and during 4 phases. Phases 1 and 2 occurred after 40 and 67 d of feeding the unbalanced basal diets, phase 3 occurred after conditioning with NaCl, CaCO(3), or NaH(2)PO(4), and phase 4 occurred 22 d after the groups were moved to 2 new (separate) locations so the animals in the different groups could not eat dirt, urine, or feces from the other pen. Preference for pomace did not differ between the groups during the initial preference tests (P = 0.62); both groups preferred NaCl > CaCO(3) = NaH(2)PO(4) (P < 0.001). As the study progressed, and lambs fed low P-high Ca had lower P and greater Ca concentrations in serum than lambs fed high P-low Ca (P < 0.001), the preference between groups diverged. In phase 2, lambs in high P-low Ca continued to prefer NaCl (P < 0.001), but lambs in low P-high Ca preferred NaH(2)PO(4) (P < 0.05). After conditioning, both groups preferred NaCl = NaH(2)PO(4) > CaCO(3) (P < 0.01 to 0.11). After the groups were moved to different locations, lambs fed low P-high Ca showed the lowest concentration (3.7 mg/dL) of inorganic P in serum for all phases (P < 0.001), and they preferred NaH(2)PO(4) > NaCl = CaCO(3) (P < 0.001). In contrast, lambs in high P-low Ca avoided NaH(2)PO(4) (P < 0.05). Lambs offered high P-low Ca showed a greater preference for CaCO(3) (P = 0.12) and NaCl (P < 0.05) and a lower preference for NaH(2)PO(4) compared with lambs fed low P-high Ca (P < 0.001). In summary, lambs discriminated among different flavored feeds containing NaCl, CaCO(3), and NaH(2)PO(4) and displayed preferences as a function of the mineral imbalance in their basal diets. Thus, it may be possible to feed Ca and P supplements free choice, such that individual animals within a group can manifest preferences based on their specific needs. PMID:18073279

Villalba, J J; Provenza, F D; Hall, J O

2008-03-01

372

Bacteria-to-Archaea ratio depending on soil depth and agrogenic impact  

NASA Astrophysics Data System (ADS)

Archaeal communities and their potential roles in the soil ecosystem are affected by a number of soil proprerties and environmental factors. Competitive interactions between Archaea and Bacteria play a particular role in spread and abundance of these two domains. Therefore, the goal of the study was to evaluate the Bacteria-to-Archaea ratio in different soils. The research was carried out at field and natural ecosystems of European part of Russia. Samples were collected within the soil profiles (3-6 horizons) of chernozem and kastanozem with distinctly different agrogenic impact. In situ hybridization with fluorescently labeled rRNA-targeted oligonucleotide probes (FISH) was used to determine the abundance of metabolically active cells of Archaea and Bacteria. The Cmic, Corg, C/N, DNA content and growth characteristics have been analyzed as well. Determination of number of metabolically active cells in chernozem under arable land and forest revealed that abundance of Archaea in topsoil under forest was higher more than 2 times comparing with arable land, but leveled off in the deeper horizons. Plowing of Chernozem decreased amount of archaeal and bacterial active cells simultaneously, however, Bacteria were more resistant to agrogenic impact than Archaea. Determination of the taxonomic composition within Bacteria domain showed a significant decrease in the abundance of phylogenetic groups Firmicutes and Actinobacteria in the topsoil under arable land comparing to the forest, which is the main reason for the declining of the total amount of prokaryotic cells. In kastanozem significant change in the number of metabolically active cells due to plowing was detected only within 40 cm soil layer, and this effect disappeared in lower horizons. The number of Archaea was higher in the upper horizons of arable as compared to virgin soil. Conversely, the number of Bacteria in the upper layers of the soil after plowing kastanozem decreased. Relationship between soil organic carbon content and the amount of soil metabolically active Bacteria and Archaea cells revealed that distribution of both Bacteria and Archaea throughout the soil profile was governed by organic matter content. Thus, the organic matter content seemed to be the main factor of declining Bacteria-to- Archaea ratio down the profile (from 7.1 to 4.2 for virgin soil and from 5 to 3.9 for arable soil). In conclusion, Archaea out-compete Bacteria under conditions of reduced energy supply.

Semenov, Mikhail; Manucharova, Natalia; Kuzyakov, Yakov

2014-05-01

373

Tabletop Tectonics: Diverse Mountain Ranges Using Flour and Graphite  

NASA Astrophysics Data System (ADS)

It has been recognized for some time that the frontal deformation zones where plates converge (foreland fold- and-thrust belts on continents and accretionary wedges at subduction zones) involve shortening over a decoupling layer, or decollement. A simple but successful way of explaining many aspects of their behavior is called the critical Coulomb wedge model, which regards these contractional wedges as analogous to the wedge-shaped mass of soil accreted in front of a bulldozer, or the wedge of snow that piles up in front of a snow plow. The shape and deformation history of the accreted wedge of soil or snow will depend upon the frictional strength of the material being plowed up and the surface over which it is being plowed. The same is true of `bulldozer' wedges consisting of many km thick piles of sediment at convergent plate margins. Using flour (or powdered milk), sandpaper, graphite, transparency sheets, and athletic field marker chalk, manipulated with sieves, brushes, pastry bags and blocks and sheets of wood, it is possible to demonstrate a wide variety of processes and tectonic styles observed at convergent plate boundaries. Model fold-and-thrust belts that behave like natural examples with a decollement that is strong (e.g., in rock without high pore fluid pressure) or weak (e.g., in a salt horizon or with elevated pore fluid pressure) can be generated simply by placing wither sandpaper or graphite beneath the flour that is pushed across the tabletop using a block of wood (the strong basement and hiterland rocks behind the fold-thrust belt). Depending upon the strength of the decollement, the cross-sectional taper of the deforming wedge will be thin or broad, the internal deformation mild or intense, and the structures either close to symmetric or strongly forward-vergent, just as at the analogous natural fold-thrust belts. Including a horizontal sheet of wood or Plexiglas in front of the pushing block allows generation of an accretionary wedge, outer-are high, and forearc basin, just as over a subduction zone. Any dark material emplaced (a pastry bag works well) atop the experiment before deformation in the form of football-field `hash marks' every 10 cm allows for easy calculation of strain distribution at any time during or after the experiment. Finally, the entire orogen can be excavated using a plastic photocopier transparency sheet. If the original set-up included occasional thin layers of red and blue field marker chalk within sedimentary column (the rest of which consists of white flour or powdered milk), excavation reveals (quite colorfully) many internal details of the fold-thrust belts that have been generated.

Davis, D. M.

2006-12-01

374

Fault Wear and Friction Evolution: Experimental Analysis  

NASA Astrophysics Data System (ADS)

Wear is an inevitable product of frictional sliding of brittle rocks as evidenced by the ubiquitous occurrence of fault gouge and slickenside striations. We present here experimental observations designed to demonstrate the relationship between wear and friction and their governing mechanisms. The experiments were conducted with a rotary shear apparatus on solid, ring-shaped rock samples that slipped for displacements up to tens of meters. Stresses, wear and temperature were continuously monitored. We analyzed 86 experiments of Kasota dolomite, Sierra White granite, Pennsylvania quartzite, Karoo gabbro, and Tennessee sandstone at slip velocities ranging from 0.002 to 0.97 m/s, and normal stress from 0.25 to 6.9 MPa. We conducted two types of runs: short slip experiments (slip distance < 25 mm) primarily on fresh, surface-ground samples, designed to analyze initial wear mechanisms; and long slip experiments (slip distance > 3 m) designed to achieve mature wear conditions and to observe the evolution of wear and friction as the fault surfaces evolved. The experiments reveal three wear stages: initial, running-in, and steady-state. The initial stage is characterized by (1) discrete damage striations, the length of which is comparable to total slip , and local pits or plow features; (2) timing and magnitude of fault-normal dilation corresponds to transient changes of normal and shear stresses; and (3) surface roughness increasing with the applied normal stress. We interpret these observations as wear mechanisms of (a) plowing into the fresh rock surfaces; (b) asperity breakage; and (c) asperity climb. The running-in stage is characterized by (1) intense wear-rate over a critical wear distance of Rd = 0.3-2 m; (2) drop of friction coefficient over a weakening distance of Dc = 0.2-4 m; (3) Rd and Dc display positive, quasi-linear relation with each other. We interpret these observations as indicating the organizing of newly-created wear particles into a 'three-body' structure that acts to lubricate the fault (Reches & Lockner, 2010). The steady-state stage is characterized by (1) relatively low wear-rate (approximately 10% of running-in wear-rate) and (2) quasi-constant friction coefficient. These observations suggest only small changes in the gouge layer in term of thickness (100 to 200 microns) and strength in this final stage. The present study indicates that (1) wear by plowing and asperity failure initiate early, during the first few millimeters of slip; and (2) wear and associated gouge formation appear as the controlling factors of friction evolution and fault weakening.

Boneh, Y.; Chang, J. C.; Lockner, D. A.; Reches, Z.

2011-12-01

375

Individual quality, survival variation and patterns of phenotypic selection on body condition and timing of nesting in birds  

USGS Publications Warehouse

Questions about individual variation in 'quality' and fitness are of great interest to evolutionary and population ecologists. Such variation can be investigated using either a random effects approach or an approach that relies on identifying observable traits that are themselves correlated with fitness components. We used the latter approach with data from 1,925 individual females of three species of ducks (tufted duck, Aythya fuligula; common pochard, Aythya ferina; northern shoveler, Anas clypeata) sampled on their breeding grounds at Engure Marsh, Latvia, for over 15 years. Based on associations with reproductive output, we selected two traits, one morphological (relative body condition) and one behavioral (relative time of nesting), that can be used to characterize individual females over their lifetimes. We then asked whether these traits were related to annual survival probabilities of nesting females. We hypothesized quadratic, rather than monotonic, relationships based loosely on ideas about the likely action of stabilizing selection on these two traits. Parameters of these relationships were estimated directly using ultrastructural models embedded within capture-recapture-band-recovery models. Results provided evidence that both traits were related to survival in the hypothesized manner. For all three species, females that tended to nest earlier than the norm exhibited the highest survival rates, but very early nesters experienced reduced survival and late nesters showed even lower survival. For shovelers, females in average body condition showed the highest survival, with lower survival rates exhibited by both heavy and light birds. For common pochard and tufted duck, the highest survival rates were associated with birds of slightly above-average condition, with somewhat lower survival for very heavy birds and much lower survival for birds in relatively poor condition. Based on results from this study and previous work on reproduction, we conclude that nest initiation date and body condition covary with both reproductive and survival components of fitness. These associations lead to a positive covariance of these two fitness components within individuals and to the conclusion that these two traits are indeed correlates of individual quality.

Blums, P.; Nichols, J.D.; Hines, J.E.; Lindberg, M.; Mednis, A.

2005-01-01

376

Dynamic phenomena in coronal flux tubes  

NASA Technical Reports Server (NTRS)

The study of stellar atmospheres and the determination of specific physical mechanisms, geometries, and magnetic structures by which coronae are maintained is examined. Ultraviolet and soft X-ray components observed in the radiative output of cool stars and the Sun require counterentropic temperature gradients for their explanation. The existence of a hot corona is recognized as a result of mechanical or fluid dynamic effects and the importance of the magnetic field in the heating is accepted. Magnetohydrodynamic energy release associated with the emergence of magnetic flux through the chromosphere and its dynamic readjustment in the corona are major counterentropic phenomena which are considered as primary candidates for corona heating. Systematic plows in coronal flux tubes result from asymmetric heating and systematic flows can exist without substantial chromospheric pressure differences.

Mariska, J. T.; Boris, J. P.

1981-01-01

377

Ground-water quality near a sewage-sludge recycling site and a landfill near Denver, Colorado  

USGS Publications Warehouse

The Metropolitan Denver Sewage Disposal District and the city and county of Denver operate a sewage-sludge recycling site and a landfill in an area about 15 miles (24 kilometers) east of Denver. The assessment of the effects of these facilities on the ground-water system indicated that five wells perforated in alluvium were found to have markedly degradedd water quality. One well is located in the landfill and water that was analyzed was obtained from near the base of the buried refuse, two others are located downgradient and near sewage-sludge burial areas, and the remaining two are located near stagnant surface ponds. Concentrations of nitrate in wells downgradient from fields where sludge is plowed into the soil were higher than background concentrations due to the effects of the sludge disposal. No evidence of water-quality degradation was detected in deeper wells perforated in the bedrock formations. (Woodard-USGS)

Robson, Stanley G.

1977-01-01

378

Supra-bubble regime for laser acceleration of coldelectron beams in tenuous plasma  

SciTech Connect

Relativistic electrons can be accelerated by an ultraintense laser pulse in the "supra-bubble" regime, that is, in the blow-out regime ahead of the plasma bubble (as opposed to the conventional method, when particles remain inside the bubble). The acceleration is caused by the ponderomotive force of the pulse, via the so-called snow-plow mechanism. The maximum energy gain, ?? ~ ?g a, is attained when the particle Lorentz factor ? is initially about ?g/a, where ?g is the pulse group speed Lorentz factor, and a is the laser parameter, proportional to the laser field amplitude. The scheme operates at a ? ?g, yielding ?? of up to that via wakefield acceleration for the same plasma and laser parameters, ?? ~ ?2g. The interaction length is shorter than that for the wake field mechanism but grows with the particle energy, hindering acceleration in multiple stages.

V.I. Geyko, I.Y. Dodin, and N.J. Fisch G.M. Fraiman

2009-01-18

379

Effects of nematophagous fungi on numbers and death rates of bacterivorous nematodes in arable soil.  

PubMed

In a series of microcosm experiments with an arable, sandy loam soil amended with sugarbeet leaf, the short-term (8 weeks) dynamics of numbers of nematodes were measured in untreated soil and in gamma-irradiated soil inoculated with either a field population of soil microorganisms and nematodes or a mixed population of laboratory-propagated bacterivorous nematode species. Sugarbeet leaf stimulated an increase in bacterivorous Rhabditidae, Cephalobidae, and a lab-cultivated Panagrolaimus sp. Differences were observed between the growth rates of the nematode population in untreated and gamma-irradiated soils, which were caused by two nematophagous fungi, Arthrobotrys oligospora and Dactylaria sp. These fungi lowered the increase in nematode numbers due to the organic enrichment in the untreated soil. We estimated the annually produced bacterivous nematodes to consume 50 kg carbon and 10 kg nitrogen per ha, per year, in the upper, plowed 25 cm of arable soil. PMID:19277342

Bouwman, L A; Hoenderboom, G H; van der Maas, K J; de Ruiter, P C

1996-03-01

380

Effects of Nematophagous Fungi on Numbers and Death Rates of Bacterivorous Nematodes in Arable Soil  

PubMed Central

In a series of microcosm experiments with an arable, sandy loam soil amended with sugarbeet leaf, the short-term (8 weeks) dynamics of numbers of nematodes were measured in untreated soil and in ?-irradiated soil inoculated with either a field population of soil microorganisms and nematodes or a mixed population of laboratory-propagated bacterivorous nematode species. Sugarbeet leaf stimulated an increase in bacterivorous Rhabditidae, Cephalobidae, and a lab-cultivated Panagrolaimus sp. Differences were observed between the growth rates of the nematode population in untreated and ?-irradiated soils, which were caused by two nematophagous fungi, Arthrobotrys oligospora and Dactylaria sp. These fungi lowered the increase in nematode numbers due to the organic enrichment in the untreated soil. We estimated the annually produced bacterivous nematodes to consume 50 kg carbon and 10 kg nitrogen per ha, per year, in the upper, plowed 25 cm of arable soil.

Bouwman, L. A.; Hoenderboom, G. H. J.; van der Maas, K. J.; de Ruiter, P. C.

1996-01-01

381

Effect of errors in positioning the sampling points on the assessment of the relationships between the remote sensing data and the soil properties  

NASA Astrophysics Data System (ADS)

The stochastic modeling of the shift in coordinates of the sampling points was performed for a typical land plot in Bryansk opolie with the purpose to assess the influence of the accuracy of the sampling point positioning on the predicted properties of the plow horizon. It was proved that, for agro-gray soils, an occasional shift of the sampling points by 2-6 m regarding the coordinates on satellite photographs of superhigh resolution may significantly change the correlation between the soil properties and the brightness in the infrared channel. Based on the modeling data, the 95% confidence interval was estimated for the possible correlation coefficients of such properties of the arable agro-gray soil as the density, moisture, specific surface, carbon, and mobile nitrogen content. The use of the brightness in the infrared channel as a covariate for building charts may noticeably improve the map's quality; however, it may unjustifiably complicate the mapping units delineation.

Samsonova, V. P.; Meshalkina, Yu. L.; Blagoveshchenskii, Yu. N.

2013-05-01

382

Friction model for single-asperity elastic-plastic contacts  

NASA Astrophysics Data System (ADS)

In this article, we present an analytical model that describes the plowing coefficient of friction for sliding, elastic-plastic contacts between a conical tip with a spherical extremity and a flat substrate. The model includes the effects of adhesion and bridges the gap between models which are based solely on dislocation activity and those based solely on interfacial effects scaling with the contact area. The Derjaguin-Muller-Toporov approximation for adhesive contact stress is used in our description of the contacts. Our model shows excellent agreement with large-scale molecular dynamics simulations and atomic force microscopy experiments of nanoscratching on copper single crystals. One important result of our study is that the model predicts coefficients of friction that are an order of magnitude higher than typically reported for nanoscale elastic contacts. Furthermore, the coefficients of friction described by the model are very close to values typical of macroscale sliding contacts.

Mishra, Maneesh; Egberts, Philip; Bennewitz, Roland; Szlufarska, Izabela

2012-07-01

383

Slurry Erosion Performance Study of Detonation Gun-Sprayed WC-10Co-4Cr Coatings on CF8M Steel Under Hydro-Accelerated Conditions  

NASA Astrophysics Data System (ADS)

In the current investigation, cermet coatings (WC-10Co-4Cr) were deposited on CF8M steel by detonation gun (D-gun) thermal spraying process. Subsequently, the slurry erosion behaviors of the coated and bare steels were investigated using a high-speed erosion test rig. Slurry collected from an actual hydro power plant was used as the abrasive media. Effects of concentration (ppm), average particle sizes and rotational speed on the slurry erosion behaviors of coated and bare steels under different experimental conditions were studied. The analysis of eroded samples was done using SEM and stylus profilometry. Signatures of microcutting, fracture of well-bonded WC grains, and fragmentations were observed on the eroded surface of WC-10Co-4Cr coating, while signatures of formation of plowing, lips, shearing of platelet, formation of crater, and micro-cutting were observed on the eroded surface of CF8M steel.

Bhandari, Sanjeev; Singh, Harpreet; Kumar, Harmesh; Rastogi, Vikas

2012-09-01

384

Effects of laser energy fluence on the onset and growth of the Rayleigh-Taylor instabilities and its influence on the topography of the Fe thin film grown in pulsed laser deposition facility  

NASA Astrophysics Data System (ADS)

The effect of laser energy fluence on the onset and growth of Rayleigh-Taylor (RT) instabilities in laser induced Fe plasma is investigated using time-resolved fast gated imaging. The snow plow and shock wave models are fitted to the experimental results and used to estimate the ablation parameters and the density of gas atoms that interact with the ablated species. It is observed that RT instability develops during the interface deceleration stage and grows for a considerable time for higher laser energy fluence. The effects of RT instabilities formation on the surface topography of the Fe thin films grown in pulsed laser deposition system are investigated (i) using different laser energy fluences for the same wavelength of laser radiation and (ii) using different laser wavelengths keeping the energy fluence fixed. It is concluded that the deposition achieved under turbulent condition leads to less smooth deposition surfaces with bigger sized particle agglomerates or network.

Mahmood, S.; Rawat, R. S.; Wang, Y.; Lee, S.; Zakaullah, M.; Tan, T. L.; Springham, S. V.; Lee, P.

2012-10-01

385

Effect of current on multiple pinches of Xe plasma in capillary discharge  

NASA Astrophysics Data System (ADS)

The effect of the current on the pinching process of Xe plasma columns pumped by capillary discharge has been studied theoretically and experimentally. An extreme ultraviolet emission monitor (E-Mon, 13.5 nm in 2% bandwidth) was applied to record the temporal evolution of the 13.5 nm (2% bandwidth) emission. According to real current waveforms, the pinching processes were simulated with the snow-plow model. Both the experimental and the simulation results showed that intensity of the 13.5 nm emission reached the maximum when the plasma was pinched to the minimum radius. The E-Mon signals and the simulations indicated that under different amplitudes of the currents the plasma could be pinched more times and faster with higher discharge current.

Xu, Qiang; Zhao, Yongpeng; Xie, Yao; Liu, Yang; Li, Qi; Wang, Qi

2014-03-01

386

A method for sampling waste corn  

USGS Publications Warehouse

Corn had become one of the most important wildlife food in the United States. It is eaten by a wide variety of animals, including white-tailed deer (Odocoileus virginianus ), raccoon (Procyon lotor ), ring-necked pheasant (Phasianus colchicus , wild turkey (Meleagris gallopavo ), and many species of aquatic birds. Damage to unharvested crops had been documented, but many birds and mammals eat waste grain after harvest and do not conflict with agriculture. A good method for measuring waste-corn availability can be essential to studies concerning food density and food and feeding habits of field-feeding wildlife. Previous methods were developed primarily for approximating losses due to harvest machinery. In this paper, a method is described for estimating the amount of waste corn potentially available to wildlife. Detection of temporal changes in food availability and differences caused by agricultural operations (e.g., recently harvested stubble fields vs. plowed fields) are discussed.

Frederick, R.B.; Klaas, E.E.; Baldassarre, G.A.; Reinecke, K.J.

1984-01-01

387

Control of Structure in Conventional Friction Stir Welds through a Kinematic Theory of Metal Flow  

NASA Technical Reports Server (NTRS)

In friction stir welding (FSW), a rotating pin is translated along a weld seam so as to stir the sides of the seam together. Metal is prevented from flowing up the pin, which would result in plowing/cutting instead of welding, by a shoulder on the pin. In conventional FSW, the weld metal rests on an "anvil", which supports the heavy "plunge" load on the tool. In this study, both embedded tungsten wires along and copper plating on the faying surfaces were used to trace the flow of AA2219 weld metal around the C-FSW tool. The effect of tool rotational speed, travel speed, plunge load, and pin thread pitch on the resulting weld metal flow was evaluated. Plan, longitudinal, and transverse section x-ray radiographs were examined to trace the metal flow paths. The results are interpreted in terms of a kinematic theory of metal flow in FSW.

Rubisoff, H.A.; Schneider, J.A.; Nunes, A.C.

2009-01-01

388

Acceleration and Compression of Charged Particle Bunches Using Counter-Propagating Laser Beams  

SciTech Connect

The nonlinear interaction between counter-propagating laser beams in a plasma results in the generation of large (enhanced) plasma wakes. The two beams need to be slightly detuned in frequency, and one of them has to be ultra-short (shorter than a plasma period). Thus produced wakes have a phase velocity close to the speed of light and can be used for acceleration and compression of charged bunches. The physical mechanism responsible for the enhanced wake generation is qualitatively described and compared with the conventional laser wakefield mechanism. The authors also demonstrate that, depending on the sign of the frequency difference between the lasers, the enhanced wake can be used as a ``snow-plow'' to accelerate and compress either positively or negatively charged bunches. This ability can be utilized in an electron-positron injector.

G. Shvets; N. J. Fisch; A. Pukhov

2000-10-17

389

The friction and wear of metals and binary alloys in contact with an abrasive grit of single-crystal silicon carbide  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with various metals and iron-base binary alloys (alloying elements Ti, Cr, Mn, Ni, Rh and W) in contact with single crystal silicon carbide riders. Results indicate that the friction force in the plowing of metal and the groove height (corresponding to the wear volume of the groove) decrease linearly as the shear strength of the bulk metal increases. The coefficient of friction and groove height generally decrease, and the contact pressure increases with an increase in solute content of binary alloys. There appears to be very good correlation of the solute to iron atomic ratio with the decreasing rate of change of coefficient of friction, the decreasing rate of change of groove height and the increasing rate of change of contact pressure with increasing solute content. These rates of change increase as the solute to iron atomic radius ratio increases or decreases from unity.

Miyoshi, K.; Buckley, D. H.

1979-01-01

390

Development of a jet-assisted cutterhead for coal-measure rocks. Mining research contract report  

SciTech Connect

Results of a laboratory research program aimed at the development of a water-jet-assisted drag-bit cutting system for coal-mine applications are presented. Two types of drag bits, a conical and a plow bit, were tested in a hard sandstone rock with jet pressures of up to 20,000 psi. Jet locations investigated were in front of and behind the bit. For each jet mounting location, three jet impingement distances with respect to bit tip were tested. The closest jet-impingement location to bit tip was found most effective, providing the greatest force reductions on the bit. Overall, significant bit force reductions up to 50% were obtained with jet assist. Also observed was a drastic reduction in airborne dust when jets were employed.

Ozdemir, L.

1986-04-01

391

Abrasive Wear Study of NiCrFeSiB Flame Sprayed Coating  

NASA Astrophysics Data System (ADS)

In the present study, abrasive wear behavior of NiCrFeSiB alloy coating on carbon steel was investigated. The NiCrFeSiB coating powder was deposited by flame spraying process. The microstructure, porosity and hardness of the coatings were evaluated. Elemental mapping was carried out in order to study the distribution of various elements in the coating. The abrasive wear behavior of these coatings was investigated under three normal loads (5, 10 and 15 N) and two abrasive grit sizes (120 and 320 grit). The abrasive wear rate was found to increase with the increase of load and abrasive size. The abrasive wear resistance of coating was found to be 2-3 times as compared to the substrate. Analysis of the scanning electron microscope images revealed cutting and plowing as the material removal mechanisms in these coatings under abrasive wear conditions used in this investigation.

Sharma, Satpal

2013-10-01

392

Colonization of rye green manure and peanut fruit debris by Aspergillus falvus and Aspergillus niger group in field soils.  

PubMed Central

Aspergillus flavus and Aspergillus niger group colonization of deep-plowed, decomposing rye green manure cover crops in peanut field soils was studied in four fields during 1972 and 1973; colonization of decomposing peanut fruits was studied in 1972 in two fields. A. flavus colonization of rye and peanut fruits was greater in soils of heavy texture, and an A. flavus population as high as 165 propagules per g of soil was observed in soil adjacent to rye, whereas A. flavus populations in soils not associated with rye were 18 propagules per g of soil or lower. Highest A. flavus populations in soil adjacent to decomposing peanut fruits were usually comparable to populations associated with rye. Little decomposing rye or peanut fruit colonization was generally observed by the A. flavus competitor, A. niger group. A. flavus may maintain or increase its inoculum potential by colonization of these and other moribund plant tissues.

Griffin, G J; Garren, K H

1976-01-01

393

Application of ecological, geological and oceanographic ERTS-1 imagery to Delaware's coastal resources management  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Data from twelve successful ERTS-1 passes over Delaware Bay have been analyzed with special emphasis on coastal vegetation, land use, current circulation, water turbidity and pollution dispersion. Secchi depth, suspended sediment concentration and transmissivity as measured from helicopters and boats were correlated with ERTS-1 image radiance. Multispectral signatures of acid disposal plumes, sediment plumes and slick were investigated. Ten vegetative cover and water discrimination classes were selected for mapping: (1) forest-land; (2) Phragmites communis; (3) Spartina patens and Distichlis spicata; (4) Spartina alterniflora; (5) cropland; (6) plowed cropland; (7) sand and bare sandy soil; (8) bare mud; (9) deep water; and (10) sediment-laden and shallow water. Canonical analysis predicted good classification accuracies for most categories. The actual classification accuracies were very close to the predicted values with 8 of 10 categories classified with greater than 90% accuracy indicating that representative training sets had been selected.

Klemas, V. (principal investigator); Bartlett, D. S.; Philpot, W. D.; Davis, G. R.; Rogers, R. H.; Reed, L.

1974-01-01

394

Microtribological Performance of Metal-doped Molybdenum Disulfide Coatings  

NASA Astrophysics Data System (ADS)

The mechanical and tribological properties of pure MoS2, pure Au, Au-MoS2 and Ti-MoS2 coatings were evaluated and examined at a microscopic scale. The metal doped MoS2 coatings had varying metal content, 5-10at% for Ti and 10-90% for Au. Reciprocating sliding wear tests were performed with a range of initial Hertzian contact pressures from 0.41 to 3.5 GPa and in air at two humidity levels (i.e. "low" being 3-5%RH and "high" being 30-40%RH). Titanium and gold were chosen for this study as metal additives due to their positive influence on the mechanical properties of the coating. The friction and wear behavior at the micro-scale were directly compared to tribological properties at the macro-scale, which were performed using an in situ tribometer. Reciprocating micro- and macro- wear tests were performed with spherical diamond tip (with 10 and 50 mum radii) and a sapphire tip (with a radius of 3.175 mm), respectively. The range of initial Hertzian contact pressures for macro-scale (i.e. between 0.41GPa and 1.2GPa) overlapped with that for micro-scale. However, the initial Hertzian contact diameters (2*a) were very different (i.e. 0.8-2.3 mum for micro-scale and 60-180 mum for macro-scale). It was observed that the small addition of Ti or Au to MoS2 improved the microtribological properties (i.e. lower friction and less wear) compared to pure MoS2 coatings. The improved microtribological properties with metal additions were attributed to an increase in the mechanical properties, decrease in adhesion, and a decrease in the interfacial shear strength. In terms of the different length scales, lower steady state friction was observed for macrotribology compared to microtribology. The higher friction at the micro- scale was explained by the greater adhesion effects and additional velocity accommodation modes (e.g. microplowing or plowing). The microplowing or plowing at the microscopic scale was attributed to the tip roughness and the inability to sustain a stable transferfilm throughout the tests at high humidity. In addition, using in situ and ex situ techniques, three different stages for solid lubrication were identified based on differences in contact area, tip shapes, and environmental conditions. The first stage has been previously observed with macrotribology on MoS 2 coatings at low humidity levels. The second stage, on the other hand, was observed for micro-tribology where the contact size is significantly smaller compared to stage one. The main wear mechanism is still adhesion, but there is also some micro-plowing. The final stage was observed for humid sliding in microtribology, where no transfer films were observed and therefore the main wear mechanism was plowing.

Stoyanov, Pantcho

395

Application of magnetic tracer method for quantification of pedoturbations in soils under different land use  

NASA Astrophysics Data System (ADS)

Pedoturbations are widely known and good classified by scientists. It is known 10 types of pedoturbations, allocated by F.D. Hole (1961) and supplemented by D.L. Johnson and collaborators (1987). They influence on many soil properties and also on migration substances (including pollutants). But there is a lack of data of quantitative assessments of pedoturbations especially in soils under different land use. In this paper are shown approaches for the use of magnetic tracer method for assessments of pedoturbation processes. This method is widely spread for study lateral solid phase soil matter (soil erosion), but first use for study pedoturbations. Magnetic tracer method is based on study of spherical magnetic particles (SMP) in soils. Origin of SMP is mainly connected with atmospheric deposition of fly ash, resulting from coal burning in steam engines of locomotives and thermal electric power stations. The period of active emission of SMP is the last 150 years. Magnetic spherules are stable and resistant to soil weathering and can be preserved in soils for decades without any clear signs of destruction. In European part of Russia and Middle West USA were analyzed 63 soil profiles under virgin forest and steppe vegetation and croplands. Vertical distribution of SMP in the upper 30 cm divided into 5 types: a) residually accumulative, b) not uniform with maximum in the upper 10 cm, c) not uniform with maximum in the 10-20 cm, d) not uniform with maximum in the 20-30 cm, e) gomogeneous. Vertical distribution of SMP reflects intensity of pedoturbations, because SMP migrate into the soils only from the atmospheric depositions. Labeled types of SMP vertical distribution are listed in order of increasing intensity of the pedoturbation. Most intensive pedoturbations are detected in arable soils. Depending on the region arable soils characterized by highest percentage of soil profiles with homogenous type of SMP distribution (up to 17%) and lowest percentage of soil profiles with residually accumulative SMP distribution (15-75%). Revealed the important role of type of plowing. On two sites in Russia with depleted type of plowing detected very high intensity of pedoturbation - homogenous type of SMP distribution was in 8-17% of soils and accumulative type - in 15-25%. Otherwise on two sites in the Middle West USA with moldboard type of plowing, homogenous type was much less (in 0-8% of soils) and accumulative type was 2-3 times more (55-75%). In virgin soils intensity of pedoturbations is much less, homogenous type of SMP distribution is not detected in any soil profiles. Furthermore on two virgin forest sites in USA and Russia percentage of soils with initial accumulative type of SMP distribution was 100%. On site in virgin steppe region of Russia - 85% of soils characterized by initial accumulative type and other 15% by not uniform with maximum in the upper 10 cm. Only on one site in forest region of Russia percentage of initial accumulative type of SMP distribution was rather low and even less than on arable soils with moldboard type of plowing - 67%.

Zhidkin, Andrey; Gennadiyev, Alexander

2014-05-01

396

Zero-tillage and corn production in eastern Canada  

SciTech Connect

During the summer of 1979, a zero-tillage experiment was conducted in which corn (maize) was grown on 68 different plots representing different soil structural status. Sixty-four of the plots had been subjected to 16 different compaction and tillage treatments and corn grown on them. No machinery traffic had been introduced to these plots since the spring of 1978. Four new plots were established which had been subjected to conventional tillage methods, those being plowing in the fall of 1978 and disc harrowing in the spring of 1979. Corn was hand seeded into all the plots and the growth, development and yield of the crop measured. Several times over the growing season, soil dry bulk density, soil moisture content and soil temperature were measured. Observation of days to emerge, tassel and silk showed that the zero-till plots performed much better than the control plots.

Raghavan, G.S.V.; Taylor, F.; Negi, S.; Douglas, E.; McKyes, E.; Tessier, S.; Burrows, J.

1981-01-01

397

Effects of Particulate Debris Morphology on the Rolling Wear Behavior of All-Steel and Si(Sub 3)N(Sub 4)-Steel Bearing Element Couples  

SciTech Connect

Rolling contact fatigue experiments were performed on all-steel and hybrid Si{sub 3}N{sub 4}-M50 steel rolling bearing systems using particulate contaminated lubricants. The particulate contaminants used were glycothermally synthesized {alpha}-Al{sub 2}O{sub 3} platelets or Arizona test dust. The effects of contaminant composition and morphology on rolling contact fatigue and wear behavior were explored. The effects of bearing element material properties on fatigue and wear behavior were also examined. Rolling wear behavior is related to bearing component material configuration and the type of particulate contaminant present in the lubricant. Component and particulate material properties such as hardness and elastic modulus are observed to affect rolling wear behavior. Wear mechanisms such as contact stress fatigue, indenting, cutting and plowing are observed.

Adair, J.H.; Mecholsky, J.J., Jr.; Mitchell, D.J.

1999-01-25

398

Comparison of alternative manure management systems: effect on the environment, total energy requirement, nutrient conservation, contribution to corn silage production and economics. Final report  

SciTech Connect

This study compares alternative dairy manure management systems operated under full scale commercial conditions. The study investigates weight of manure handled per cow per year, labor and energy requirements, effect on the environment, nutrient conservation, corn silage production and total annual operating costs. The dairy production facility used was a confinement stall barn at the Agway Farm Research Center, Tully, New York. Provisions were made to handle the manure from the barn in three ways: (1) directly into a spreader for daily spreading, (2) by gravity into a liquid manure storage tank for spring application and immediate plow down, (3) hydraulic ram to a roof-covered above-ground manure storage for spring and fall spreading. Results of the study show that a manure storage system can reduce annual labor requirements by 65 percent and fuel requirement by 60 percent or more, compared to daily spreading.

Martin, R.O.; Matthews, D.L.

1983-09-01

399

Ultrarelativistic electromagnetic pulses in plasmas  

NASA Technical Reports Server (NTRS)

The physical processes of a linearly polarized electromagnetic pulse of highly relativistic amplitude in an underdense plasma accelerating particles to very high energies are studied through computer simulation. An electron-positron plasma is considered first. The maximum momenta achieved scale as the square of the wave amplitude. This acceleration stops when the bulk of the wave energy is converted to particle energy. The pulse leaves behind as a wake a vacuum region whose length scales as the amplitude of the wave. The results can be explained in terms of a snow plow or piston-like action of the radiation on the plasma. When a mass ratio other than unity is chosen and electrostatic effects begin to play a role, first the ion energy increases faster than the electron energy and then the electron energy catches up later, eventually reaching the same value.

Ashour-Abdalla, M.; Leboeuf, J. N.; Tajima, T.; Dawson, J. M.; Kennel, C. F.

1981-01-01

400

An Augmented Lagrangian Method for Sliding Contact of Soft Tissue  

PubMed Central

Despite the importance of sliding contact in diarthrodial joints, only a limited number of studies have addressed this type of problem, with the result that mechanical behavior of articular cartilage in daily life remains poorly understood. In this paper, a finite element formulation is developed for the sliding contact of biphasic soft tissues. The Augmented Lagrangian method is used to enforce the continuity of contact traction and fluid pressure across the contact interface. The resulting method is implemented in the commercial software COMSOL Multiphysics. The accuracy of the new implementation is verified using an example problem of sliding contact between a rigid, impermeable indenter and a cartilage layer for which analytical solutions have been obtained. The new implementation’s capability to handle a complex loading regime is verified by modeling plowing tests of the temporomandibular joint (TMJ) disc.

Guo, Hongqiang; Nickel, Jeffrey C.; Iwasaki, Laura R.; Spilker, Robert L.

2012-01-01

401

The uses of ERTS-1 imagery in the analysis of landscape change. [agriculture, strip mining forests, urban-suburban growth, and flooding in Tennessee, Kentucky, Mississippi, and Alabama  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. The analysis of strip mining from ERTS-1 data has resulted in the mapping of landscape changes for the Cumberland Plateau Test Site. Several mapping experiments utilizing ERTS-1 data have been established for the mapping of state-wide land use regions. The first incorporates 12 frames of ERTS-1 imagery for the generalized thematic mapping of forest cover for the state of Tennessee. In another mapping effort, 14 ERTS-1 images have been analyzed for plowed ground signatures to produce a map of agricultural regions for Tennessee, Kentucky, and the northern portions of Mississippi and Alabama. Generalized urban land use categories and transportation networks have been determined from ERTS-1 imagery for the Knoxville Test Site. Finally, through the analysis of ERTS-1 imagery, short-lived phenomena such as the 1973 spring floods on the Mississippi River in western Tennessee, have been detected, monitored, and mapped.

Rehder, J. B. (principal investigator)

1974-01-01

402

Tribological behavior of Ti-Al-Si-C-N hard coatings deposited by hybrid arc-enhanced magnetron sputtering  

SciTech Connect

Ti-Al-Si-C-N hard coatings are deposited on high speed steel by hybrid arc-enhanced magnetron sputtering, and the hardness, adhesion, and tribological behavior are studied. On account of the nanocomposite structure, the coatings possess hardness of more than 30 GPa. Failure of the coating during the scratch test is due to the buckling and wedge spallation failure mechanism. Compared to Ti-Al-Si-N, the presence of C in the Ti-Al-Si-C-N coatings leads to reduced friction coefficient and wear rate, indicating effective lubrication rendered by amorphous C. According to the wear tracks examined by scanning electron microscopy, the wear mechanism can be explained by plowing abrasion.

Wu Guizhi; Ma Shengli; Xu Kewei; Chu, Paul K [State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049 (China); Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong)

2012-03-15

403

Semi-automatic crop inventory from sequential ERTS-1 imagery  

NASA Technical Reports Server (NTRS)

The detection of a newly introduced crop into the Imperial (California) Valley by sequential ERTS-1 imagery is proving that individual crop types can be identified by remote sensing techniques. Initial results have provided an extremely useful product for water agencies. A system for the identification of field conditions enables the production of a statistical summary within two to three days of receipt of the ERTS-1 imagery. The summary indicates the total acreage of producing crops and irrigated planted crops currently demanding water and further indicates freshly plowed fields that will be demanding water in the near future. Relating the field conditions to the crop calendar of the region by means of computer techniques will provide specific crop identification for the 8000 plus fields.

Johnson, C. W.; Coleman, V. B.

1973-01-01

404

Effects of plant densities and management of purple nutsedge on sugarcane yield and effect of growth stages and main way of herbicides contact and absorption on the control of tubers.  

PubMed

Field experiments carried out with Cyperus rotundus L. at low (58-246), medium (318-773), and high (675-1198 shoots/m2) densities showed sugarcane yield reductions of 13.5, 29.3, and 45.2%, respectively in relation to the control. In the second field experiment, the integration of a mechanic method with two sequences of plowing and disking operations in the dry season, and complementary applications of trifloxysulfuron-sodium + ametrine and sulfentrazone (rainy season) was studied. Average of the chain connected to original shoot showed 92, 95, and 65% of reduction with trifloxysulfuron-sodium + ametrine and surfactant, at the application stages "early," preflowering, and full flowering, respectively. PMID:15656168

Durigan, Julio Cezar

2005-01-01

405

Effects of laser energy fluence on the onset and growth of the Rayleigh-Taylor instabilities and its influence on the topography of the Fe thin film grown in pulsed laser deposition facility  

SciTech Connect

The effect of laser energy fluence on the onset and growth of Rayleigh-Taylor (RT) instabilities in laser induced Fe plasma is investigated using time-resolved fast gated imaging. The snow plow and shock wave models are fitted to the experimental results and used to estimate the ablation parameters and the density of gas atoms that interact with the ablated species. It is observed that RT instability develops during the interface deceleration stage and grows for a considerable time for higher laser energy fluence. The effects of RT instabilities formation on the surface topography of the Fe thin films grown in pulsed laser deposition system are investigated (i) using different laser energy fluences for the same wavelength of laser radiation and (ii) using different laser wavelengths keeping the energy fluence fixed. It is concluded that the deposition achieved under turbulent condition leads to less smooth deposition surfaces with bigger sized particle agglomerates or network.

Mahmood, S. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Department of Physics, University of Karachi, Karachi 75270 (Pakistan); Rawat, R. S.; Wang, Y.; Lee, S.; Tan, T. L.; Springham, S. V.; Lee, P. [National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616 (Singapore); Zakaullah, M. [Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

2012-10-15

406

Evaluation of remote sensing in control of pink bollworm in cotton. [Imperial Valley, Coachella Valley, and Palo Verde Valley, California  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. This investigation is to evaluate the use of a satellite in monitoring the cotton production regulation program of the State of California as an aid in controlling pink bollworm infestation in the southern deserts of California. Color combined images of ERTS-1 multispectral images simulating color infrared are being used for crop identification. The status of each field (crop, bare, harvested, wet, plowed) is mapped from the imagery and is then compared to ground survey information taken at the time of ERTS-1 overflights. A computer analysis has been performed to compare field and satellite data to a crop calendar. Correlation to date has been 97% for field condition. Actual crop identification varies; cotton identification is only 63% due to lack of full season coverage.

Lewis, L. N. (principal investigator); Coleman, V. B.; Johnson, C. W.

1974-01-01

407

Friction and wear characteristics of iron-chromium alloys in contact with themselves and silicon carbide  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with various iron-chromium alloys in contact with (1) themselves, (2) single crystal silicon carbide disks, and (3) single crystal abrasive grit of silicon carbide. Results indicate the coefficients of friction for the alloys sliding against themselves are between those for pure iron and pure chromium, and are only slightly different with 1, 5, 9, 14, and 19 weight percent chromium in iron. The wear is due, primarily, to shearing, or tearing fracture, of the cohesive bonds in the bulk metal and plowing of the bulk by lumps of wear debris. There are only slight differences in the coefficients of friction for the various alloys when sliding on silicon carbide. The coefficient of friction for the alloys are higher than those for pure iron and pure chromium. Alloy hardening observed in the alloys plays a dominant role in controlling the abrasive friction and wear behavior of the alloys.

Miyoshi, K.; Buckley, D. H.

1979-01-01

408

An Unremembered Diversity: Mixed Husbandry and the American Grasslands  

PubMed Central

The Green Revolution of the 1960s brought about a dramatic rise in global crop yields. But, as most observers acknowledge, this has come at a considerable cost to biodiversity. Plant breeding, synthetic fertilizers, and mechanization steadily narrowed the number of crop varieties commercially available to farmers and promoted fencerow-to-fencerow monocultures. Many historians trace the origins of this style of industrialized agriculture to the last great plow-up of the Great Plains in the 1920s. In the literature, farms in the plains are often described metaphorically as wheat factories, degrading successive landscapes. While in many ways these farms were a departure from earlier forms of husbandry in the American experience, monocultures were quite rare during the early transformation of the plains. Analysis of a large representative sample, based on manuscript agricultural censuses and involving twenty-five townships across the state of Kansas, demonstrates that diverse production reached even the most challenging of plains landscapes.

SYLVESTER, KENNETH; CUNFER, GEOFF

2009-01-01

409

Patterns of rock fragment cover generated by tillage erosion  

NASA Astrophysics Data System (ADS)

Intensively cultivated areas in the upper part of the Guadalentin catchment (southeast Spain) show a systematic spatial pattern of surface rock fragment cover ( Rc). The objective of this paper is to quantify and to explain this spatial rock fragment cover pattern. Therefore, a map of an intensively cultivated area of 5 km 2 was digitised, and for each pixel total topographic curvature was calculated. Next, rock fragment cover was determined photographically at 35 sites with a range of total slope curvatures. A linear relation between total curvature and rock fragment cover was found, except for narrow concavities. It was hypothesised that this pattern can be explained by a significant net downslope movement of rock fragments and fine earth by tillage. The displacement distances of rock fragments by tillage with a duckfoot chisel were measured by monitoring the displacement of tracers (painted rock fragments and aluminium cubes) on 5 sites having different slopes. The rare of tillage erosion for one tillage pass with a duckfoot chisel, expressed by the diffusion constant ( k), equals 282 kg/m for up and downslope tillage and only 139 kg/m for contour tillage. Nomograms indicate that mean denudation rates in almond groves due to tillage erosion (3 to 5 tillage passes per year) can easily amount to 1.5-2.6 mm/year for contour tillage and up to 3.6-5.9 mm/year for up- and downslope tillage for a field, 50 m long and having a slope of 20%. These figures are at least one order of magnitude larger than reported denudation rates caused by water erosion in similar environments. Hence tillage erosion contributes significantly to land degradation. The downslope soil flux induced by tillage not only causes considerable denudation on topographic convexities (hill tops and spurs) and upper field boundaries but also an important sediment accumulation in topographic concavities (hollows and valley bottoms) and at lower field boundaries. Kinetic sieving (i.e. the upward migration of rock fragments) by the tines of the duckfoot chisel also concentrates the largest rock fragments in the topsoil in such a way that a rock fragment mulch develops in narrow valleys and at the foot of the slopes. These results clearly indicate that tillage erosion is the main process responsible for the observed rock fragment cover pattern in the study area. Since the study area is representative for many parts of southern Spain where almond groves have expanded since 1970, the results have a wider application. They show to what extent intensive tillage of steep slopes has contributed to the increase in soil degradation, to changes in hillslope morphology (i.e. strong denudation of convexities, development of lynchets and rapid infilling of narrow valley bottoms) and to the development of rock fragment cover patterns which control the spatial variability of the hydrological and water erosion response within such landscapes.

Poesen, Jean; Wesemael, Bas van; Govers, Gerard; Martinez-Fernandez, José; Desmet, Philippe; Vandaele, Karel; Quine, Timothy; Degraer, Greet

1997-03-01

410

Water erosion during a 17-year period under two crop rotations in four soil management systems on a Southbrazilian Inceptisol  

NASA Astrophysics Data System (ADS)

Soil erosion still remains a persistent issue in the world, and this in spite of the efforts to ameliorate soil management systems taken into account the point of view of environmental protection against soil losses. In South Brazil water erosion is mainly associated to rainfall events with a great volume and high intensity, which are more or less evenly distributed all over the year. Nowadays, direct drilling is the most widely soil management system used for the main crops of the region. However, some crops still are grown on conventionally tilled soils, which means mainly ploughing and harrowing and less frequently chisel ploughing. In Lages-Santa Catarina State, Brazil, a plot experiment under natural rain was started in 1992 on an Inceptisol with the aim of quantifying soil and water losses. Treatments included bare and vegetated plots. The crop succession was: oats (Avena strigosa), soybean (Glycine max), vetch (Vicia sativa), maize (Zea mays), fodder radish (Raphanus sativus) and beans (Phaseolus vulgaris). Soil tillage systems investigated in this study were: i) conventional tillage (CT), ii) reduced tillage (MT), iii) no tillage (NT) under crop rotation and iv) conventional tillage on bare soil (BS). Treatments CT and BS involved ploughing plus twice harrowing, whereas MT involved chisel ploughing plus harrowing. Rainfall erosivity from January 1 1992 to December 31 2009 was calculated. Soil losses from the BS treatment along the 17 year study period were higher than 1200 Mg ha-1. Crop cover significantly reduced erosion, so that under some crops soil losses in the CT treatment were 80% lower than in the BS treatment. In turn soil losses in the MT treatment, where tillage was performed by chiselling and harrowing, were on average about 50% lower than in the CT treatment. No tillage was the most efficient soil management system in reducing soil erosion, so that soil losses in the NT treatment were about 98% lower than in the BS treatment. The three vegetated treatments, CT, MT and NT showed a lower efficiency in reducing water losses than soil losses. Water losses by runoff during a number of events were of the same order of magnitude for all the management systems studied here; which was mainly true when the volume of rainfall was high and the lag between successive events was small. In general, soil losses in the autumn-winter seasons were lower than under the spring-summer seasons. Soil losses showed a positive correlation with rainfall erosivity. However, the degree of dependence between these two variables decreased as the efficiency of soil management in controlling soil erosion increased. The large soil and water losses in the BS and CT treatments suggest that there is a need to implement soil conservation measures in the study region. In this context soil conservation would take advantage from soil cover by previous crop residue as well as from terrace building. Acknowledgement: This work was partly supported by Spanish Ministry of Education (Project CGL2005-08219-C02).

Bertol, Ildegardis; Vidal Vázquez, Eva; Paz Ferreiro, Jorge

2010-05-01

411

Stellar Interlopers Caught Speeding Through Space  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] [figure removed for brevity, see original site] [figure removed for brevity, see original site] [figure removed for brevity, see original site] Figure 1 Figure 2 Figure 3 Figure 4 Click on individual image for larger view

Resembling comets streaking across the sky, these four speedy stars are plowing through regions of dense interstellar gas and creating brilliant arrowhead structures and trailing tails of glowing gas.

These bright arrowheads, or bow shocks, can be seen in these four images taken with NASA's Hubble Space Telescope. The bow shocks form when the stars' powerful stellar winds, streams of matter flowing from the stars, slam into surrounding dense gas. The phenomenon is similar to that seen when a speeding boat pushes through water on a lake.

The stars in these images are among 13 runaway stars spotted by Hubble's Advanced Camera for Surveys. The stars appear to be young, just millions of years old. Their ages are based on their colors and the presence of strong stellar winds, a signature of youthful stars.

Depending on their distance from Earth, the bullet-nosed bow shocks could be 100 billion to a trillion miles wide (the equivalent of 17 to 170 solar system diameters, measured out to Neptune's orbit). The bow shocks indicate that the stars are moving fast, more than 180,000 kilometers an hour (more than 112,000 miles an hour) with respect to the dense gas they are plowing through. They are traveling roughly five times faster than typical young stars, relative to their surroundings.

The high-speed stars have traveled far from their birth places. Assuming their youthful phase lasts only a million years and they are moving at roughly 180,000 kilometers an hour, the stars have journeyed 160 light-years.

The Hubble observations were taken between October 2005 and July 2006.

2009-01-01

412

Disturbance alters the phylogenetic composition and structure of plant communities in an old field system.  

PubMed

The changes in phylogenetic composition and structure of communities during succession following disturbance can give us insights into the forces that are shaping communities over time. In abandoned agricultural fields, community composition changes rapidly when a field is plowed, and is thought to reflect a relaxation of competition due to the elimination of dominant species which take time to re-establish. Competition can drive phylogenetic overdispersion, due to phylogenetic conservation of 'niche' traits that allow species to partition resources. Therefore, undisturbed old field communities should exhibit higher phylogenetic dispersion than recently disturbed systems, which should be relatively 'clustered' with respect to phylogenetic relationships. Several measures of phylogenetic structure between plant communities were measured in recently plowed areas and nearby 'undisturbed' sites. There was no difference in the absolute values of these measures between disturbed and 'undisturbed' sites. However, there was a difference in the 'expected' phylogenetic structure between habitats, leading to significantly lower than expected phylogenetic diversity in disturbed plots, and no difference from random expectation in 'undisturbed' plots. This suggests that plant species characteristic of each habitat are fairly evenly distributed on the shared species pool phylogeny, but that once the initial sorting of species into the two habitat types has occurred, the processes operating on them affect each habitat differently. These results were consistent with an analysis of correlation between phylogenetic distance and co-occurrence indices of species pairs in the two habitat types. This study supports the notion that disturbed plots are more clustered than expected, rather than 'undisturbed' plots being more overdispersed, suggesting that disturbed plant communities are being more strongly influenced by environmental filtering of conserved niche traits. PMID:19763265

Dinnage, Russell

2009-01-01

413

Disturbance Alters the Phylogenetic Composition and Structure of Plant Communities in an Old Field System  

PubMed Central

The changes in phylogenetic composition and structure of communities during succession following disturbance can give us insights into the forces that are shaping communities over time. In abandoned agricultural fields, community composition changes rapidly when a field is plowed, and is thought to reflect a relaxation of competition due to the elimination of dominant species which take time to re-establish. Competition can drive phylogenetic overdispersion, due to phylogenetic conservation of ‘niche’ traits that allow species to partition resources. Therefore, undisturbed old field communities should exhibit higher phylogenetic dispersion than recently disturbed systems, which should be relatively ‘clustered’ with respect to phylogenetic relationships. Several measures of phylogenetic structure between plant communities were measured in recently plowed areas and nearby ‘undisturbed’ sites. There was no difference in the absolute values of these measures between disturbed and ‘undisturbed’ sites. However, there was a difference in the ‘expected’ phylogenetic structure between habitats, leading to significantly lower than expected phylogenetic diversity in disturbed plots, and no difference from random expectation in ‘undisturbed’ plots. This suggests that plant species characteristic of each habitat are fairly evenly distributed on the shared species pool phylogeny, but that once the initial sorting of species into the two habitat types has occurred, the processes operating on them affect each habitat differently. These results were consistent with an analysis of correlation between phylogenetic distance and co-occurrence indices of species pairs in the two habitat types. This study supports the notion that disturbed plots are more clustered than expected, rather than ‘undisturbed’ plots being more overdispersed, suggesting that disturbed plant communities are being more strongly influenced by environmental filtering of conserved niche traits.

Dinnage, Russell

2009-01-01

414

Effects of agricultural land-management practices on water quality in northeastern Guilford County, North Carolina, 1985-90  

USGS Publications Warehouse

The effects of different agricultural land- management practices on sediment, nutrients, and selected pesticides in surface water, and on nutrients and pesticides in ground water were studied in four small basins in the Piedmont of North Carolina. The basins included two adjacent basins in row-crop fields, a mixed land-use basin, and a forested basin. One of the row-crop fields was farmed using conservation land-management practices, including strip cropping, contour plowing, field borders, and grassed waterways. The other field was farmed using standard land- management practices, including continuous cropping, straight-row plowing, and ungrassed waterways. The sediment yield for the standard land-management basin was 2.3 times that for the conservation land-management basin, 14.1 times that for the mixed land-use basin, and 19.5 times that for the forested basin. Nutrient concentra- tions in surface water from the row-crop and mixed land-use basins were higher than those in surface water for the forested basin. Nutrient concentra- tions in soil water and ground water beneath the row-crop basins were lower than those in surface- water runoff for these basins. The lowest nutrient concentrations measured in the row-crop basins generally were in soil-water samples collected just below the root zone (3-foot depth) and in ground water. No significant differences in pesticide concentrations were identified between the surface-water runoff from the standard land- management basin and that from the conservation land-management basin. Concentrations of the soil pesticides isopropalin and flumetralin were higher in the standard land-management basin than in the conservation land-management basin.

Harned, D. A.

1994-01-01

415

Assessment of high resolution digital elevation model for deep humus-rich sediments delineation at a plot scale  

NASA Astrophysics Data System (ADS)

Resolution and quality of digital elevation models is a key factor in erosion modeling. Spatial estimates of erosion and sedimentation rates are important for soil organic carbon stocks prediction or delineation of newly formed soil cover by degradation and sedimentation of soil material. Such analysis can be sensitive to DEM vertical accuracy and horizontal resolution. LIDAR data can provide very precise DEMs with very high resolution. In our study we used ground based LIDAR data with 10cm pixel. At such resolution, not only naturally formed terrain features are observed, but also anthropogenic features are depicted. Anthropogenic features are represented by more significant objects like hedges or ditches that can significantly influence the water and sediment movement in the landscape on one hand, on the other hand less significant anthropogenic impact can influence the terrain surface. Plot management forms a regular network consisting of parallel linear features given by plowing operations. At our research plot, such features depicted by DEM form specific flow direction (drainage) pattern over the area comparing to coarser resolution DEMs. We focused on comparison of differently preprocessed DEMs for deep humus-rich sediments depth prediction. We compared success rate of prediction models based on original DEM, DEMs with different resampling (resolution) and modeling of original DEM adding random noise given by size of plowing based terrain pattern. The study showed that original high resolution DEM significantly decreases the possibility of soil depth prediction. The actual very precise surface description is not very relevant for GIS modeling due to sensitivity of the models. DEMs depicting the wider constellations of the terrain were more successful in the prediction. The study was supported by grant nr. 13-07516P of the Czech science foundation and by grant nr. QJ1230319 of the Ministry of Agriculture.

Penížek, Vít; Zádorová, Tereza

2014-05-01

416

Arteriovenous extracorporeal lung assist allows for maximization of oscillatory frequencies: a large-animal model of respiratory distress  

PubMed Central

Background Although the minimization of the applied tidal volume (VT) during high-frequency oscillatory ventilation (HFOV) reduces the risk of alveolar shear stress, it can also result in insufficient CO2-elimination with severe respiratory acidosis. We hypothesized that in a model of acute respiratory distress (ARDS) the application of high oscillatory frequencies requires the combination of HFOV with arteriovenous extracorporeal lung assist (av-ECLA) in order to maintain or reestablish normocapnia. Methods After induction of ARDS in eight female pigs (56.5 ± 4.4 kg), a recruitment manoeuvre was performed and intratracheal mean airway pressure (mPaw) was adjusted 3 cmH2O above the lower inflection point (Plow) of the pressure-volume curve. All animals were ventilated with oscillatory frequencies ranging from 3–15 Hz. The pressure amplitude was fixed at 60 cmH2O. At each frequency gas exchange and hemodynamic measurements were obtained with a clamped and de-clamped av-ECLA. Whenever the av-ECLA was de-clamped, the oxygen sweep gas flow through the membrane lung was adjusted aiming at normocapnia. Results Lung recruitment and adjustment of the mPaw above Plow resulted in a significant improvement of oxygenation (p < 0.05). Compared to lung injury, oxygenation remained significantly improved with rising frequencies (p < 0.05). Normocapnia during HFOV was only maintained with the addition of av-ECLA during frequencies of 9 Hz and above. Conclusion In this animal model of ARDS, maximization of oscillatory frequencies with subsequent minimization of VT leads to hypercapnia that can only be reversed by adding av-ECLA. When combined with a recruitment strategy, these high frequencies do not impair oxygenation

Muellenbach, Ralf M; Kuestermann, Julian; Kredel, Markus; Johannes, Amelie; Wolfsteiner, Ulrike; Schuster, Frank; Wunder, Christian; Kranke, Peter; Roewer, Norbert; Brederlau, Jorg

2008-01-01

417

Soil Carbon Chronosequnces from Post-Agricultural Land in Western New England  

NASA Astrophysics Data System (ADS)

Using quantitative soil pits, we sampled chronosequences of post-agricultural northern hardwood forest soils in the Hopkins Memorial Forest (Williamstown, MA) to determine the amount of carbon lost during the period of agricultural use, as well as the rates at which C accumulates after abandonment. Chronosequences based on the time of abandonment were developed for the three main agricultural uses: cultivated cropland, pasture or hay, and woodlot. Active farms served as our theoretical zero time points and old growth stands in the region served as our likely maximum for C-accumulation. We then tested this chronosequence model throughout the three main physiographic provinces of the Berkshire-Taconic landscape: carbonate lowlands, Taconic uplands, and Berkshire highlands. Our data show a significant direct relationship between time since abandonment and carbon amount for the organic horizons (Oe and Oa) of cultivated as well as pastured or hayed plots but not for stands formerly used as woodlots. Likewise there was a significant relationship between C content and time for plowed horizons (0-20 cm) of cultivated ground, but not for the top 20 cm of mineral soils that were formerly pasture, hay, or woodlot. Our best estimate suggests that cultivation reduced the C-content of plowed soils by 50% to a depth of 20 cm, and that complete recovery of the C-pool requires approximately 120 years. Management practices of post-settlement New England farms differ significantly from those used by modern farms. These methodological differences complicate efforts to quantify the recovery of carbon in the western New England landscape.

Clark, J. D.; Johnson, A. H.; Richter, S. L.; Art, H. W.

2008-12-01

418

Responses of Active Bacterial and Fungal Communities in Soils under Winter Wheat to Different Fertilizer and Pesticide Regimens  

PubMed Central

The composition of the active microbial (bacterial and fungal) soil community in an arable wheat field subjected to different management practices was examined at five times during a 1-year period. Field sections were fertilized either at good agricultural practice (GAP) levels or at reduced levels (0.5× GAP) and were inoculated with vesicular arbuscular mycorrhizae (VAM) at the same time. Field subsections were treated either with or without pesticides. Changes in the active microbial communities were investigated by denaturing gradient gel electrophoresis analysis of reverse transcription-PCR-amplified 16S and 18S rRNA. Microbial community structure was primarily determined by season, and the seasonal trends were similar for the fungal and bacterial components. Between-sample microbial heterogeneity decreased under a mature crop in the summer but increased following harvesting and plowing. Although similar overall trends were seen for the two microbial components, sample variability was greater for the fungal community than for the bacterial community. The greatest management effects were due to GAP fertilization, which caused increases in the bacterial numbers in the total and culturable communities. Microbial biomass similarly increased. GAP fertilization also caused large shifts in both the active bacterial community structure and the active fungal community structure and additionally resulted in a decrease in the heterogeneity of the active bacterial community. Pesticide addition did not significantly affect bacterial numbers or heterogeneity, but it led to major shifts in the active soil bacterial community structure. PCR primers specific for Glomales 25S rRNA genes were used to monitor the VAM population following inoculation. Glomales were detected initially only in VAM-inoculated field sections but were subsequently detected in noninoculated field sections as the season progressed. After plowing, the level of Glomales was reduced in noninoculated field sections but remained high in VAM-inoculated field sections. Inoculation of VAM correlated with elevated soil phosphate and carbon levels.

Girvan, Martina S.; Bullimore, Juliet; Ball, Andrew S.; Pretty, Jules N.; Osborn, A. Mark

2004-01-01

419

Effects of chipping, grinding, and heat on survival of emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae), in chips.  

PubMed

The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), a phloem-feeding insect from Asia, was identified in 2002 as the cause of widespread ash (Fraxinus sp.) mortality in southeastern Michigan and Essex County, Ontario. Most larvae overwinter as nonfeeding prepupae in the outer sapwood or thick bark of large trees. In a series of studies, we evaluated effects of grinding, chipping, and heat treatment on survival of A. planipennis prepupae in ash material. Heavily infested ash bolts containing roughly 8,700 prepupae were processed by a horizontal grinder with either a 2.5- or 10-cm screen. There was no evidence of A. planipennis survival in chips processed with the 2.5-cm screen, but eight viable prepupae were recovered from chips processed with the 10-cm screen. We chiseled additional sentinel chips with prepupae from ash logs and buried 45 in each chip pile. In total, six prepupae in sentinel chips survived the winter, but we found no sign of adult A. planipennis emergence from the processed chips. Subsequently, we assessed prepupal survival in chips processed by a chipper or a horizontal grinder fit with 5-, 10-, or 12.7-cm screens. An estimated 1,565 A. planipennis prepupae were processed by each treatment. Chips from the chipper were shorter than chips from the grinder regardless of the screen size used. No live prepupae were found in chips produced by the chipper, but 21 viable prepupae were found in chips from the grinder. Infested wood and bark chips chiseled from logs were held in ovens at 25, 40, or 60 degrees C for 8, 24, or 48 h. Prepupal survival was consistently higher in wood chips than bark chips at 40 degrees C, whereas no prepupae survived exposure to 60 degrees C for eight or more hours. In a second study, prepupae in wood chips were exposed to 40, 45, 50, 55, or 60 degrees C for 20 or 120 min. Some prepupae survived 20 min of exposure to all temperatures. No prepupae survived exposure to 60 degrees C for 120 min, but 17% survived exposure to 55 degrees C for 120 min, suggesting that some fraction of the population may survive internationally recognized phytosanitary standards (ISPM-15) for treatment of wood packing material. PMID:17849884

McCullough, Deborah G; Poland, Therese M; Cappaert, David; Clark, Erin L; Fraser, Ivich; Mastro, Victor; Smith, Sarah; Pell, Christopher

2007-08-01

420

Rotary Percussive Auto-Gopher for Deep Drilling and Sampling  

NASA Technical Reports Server (NTRS)

The term "rotary percussive auto-gopher" denotes a proposed addition to a family of apparatuses, based on ultrasonic/ sonic drill corers (USDCs), that have been described in numerous previous NASA Tech Briefs articles. These apparatuses have been designed, variously, for boring into, and/or acquiring samples of, rock or other hard, brittle materials of geological interest. In the case of the rotary percussive autogopher, the emphasis would be on developing an apparatus capable of penetrating to, and acquiring samples at, depths that could otherwise be reached only by use of much longer, heavier, conventional drilling-and-sampling apparatuses. To recapitulate from the prior articles about USDCs: A USDC can be characterized as a lightweight, low-power jackhammer in which a piezoelectrically driven actuator generates ultrasonic vibrations and is coupled to a tool bit through a free mass. The bouncing of the free mass between the actuator horn and the drill bit converts the actuator ultrasonic vibrations into sonic hammering of the drill bit. The combination of ultrasonic and sonic vibrations gives rise to a hammering action (and a resulting chiseling action at the tip of the tool bit) that is more effective for drilling than is the microhammering action of ultrasonic vibrations alone. The hammering and chiseling actions are so effective that the size of the axial force needed to make the tool bit advance into soil, rock, or another material of interest is much smaller than in ordinary rotary drilling, ordinary hammering, or ordinary steady pushing. The predecessor of the rotary percussive auto-gopher is an apparatus, now denoted an ultrasonic/sonic gopher and previously denoted an ultrasonic gopher, described in "Ultrasonic/ Sonic Mechanism for Drilling and Coring" (NPO-30291), NASA Tech Briefs Vol. 27, No. 9 (September 2003), page 65. The ultrasonic/sonic gopher is intended for use mainly in acquiring cores. The name of the apparatus reflects the fact that, like a gopher, it periodically stops advancing at the end of the hole to bring excavated material (in this case, a core sample) to the surface, then re-enters the hole to resume the advance of the end of the hole. By use of a cable suspended from a reel on the surface, the gopher is lifted from the hole to remove a core sample, then lowered into the hole to resume the advance and acquire the next core sample.

Bar-Cohen, Yoseph; Badescu, Mircea; Sherrit, Stewart

2009-01-01

421

Evaluating TerraSAR-X for the identification of tillage occurrence over an agricultural area in Canada  

NASA Astrophysics Data System (ADS)

Tillage practices can affect the long term sustainability of agricultural soils as well as a variety of soil processes that impact the environment. The benefits of reduced tillage and no-till practices over agriculture fields are well documented and include: (1) significant reductions in wind and water erosion mitigating nutrient and pesticide runoff into waterways; (2) increasing and/or maintaining soil organic matter; (3) increasing biological activity and improving soil structure; and (4) increasing soil carbon and its sequestration. Information on tillage activities assists in implementing policies and programs to promote beneficial management practices (BMPs), and in monitoring the success of these initiatives. Agriculture and Agri-Food Canada supports environmentally responsible agriculture and has identified this as one of their priorities. Thus, tillage information requirements have become increasingly important to a number of programs and policies within the department. Rapid, accurate and objective methods are required to map and monitor tillage activities. Earth observing satellites can assist with targeting and monitoring land management activities. For the last decade, research has clearly demonstrated that complementary information provided by both optical and radar satellite sensors are fundamental in developing an agricultural land management monitoring system. Launched in June 2007, the TerraSAR-X is a radar satellite acquiring data at the X-band frequency (9.6 GHz). The application of TerraSAR-X data for conservation tillage mapping has been somewhat limited, and thus this study investigates its use in determining tillage occurrence. An HH-HV TerraSAR-X image was acquired on November 4, 2009 and ground data were also collected characterizing tillage conditions at the time of acquisition. Backscatter responses were analyzed to identify tillage occurrence and to differentiate between untilled, chiseled and moldboard ploughed fields. Preliminary analysis showed that HH polarization can better contribute to tillage discrimination than compared to HV polarization and that the backscatter response can be used to discriminate untilled fields from ones that are moldboard ploughed. However, chiseled fields were often confused with highroughness (rms height~1.30 cm) untilled fields and moldboard ploughed fields. Fully polarimetric X-band radar datasets could potentially contribute more information to mapping tillage conditions.

Pacheco, Anna M.; McNairn, Heather; Merzouki, Amine

2010-10-01

422

Interspecies transmission and limited persistence of low pathogenic avian influenza genomes among Alaska dabbling ducks  

USGS Publications Warehouse

The reassortment and geographic distribution of low pathogenic avian influenza (LPAI) virus genes are well documented, but little is known about the persistence of intact LPAI genomes among species and locations. To examine persistence of entire LPAI genome constellations in Alaska, we calculated the genetic identities among 161 full-genome LPAI viruses isolated across 4. years from five species of duck: northern pintail (Anas acuta), mallard (Anas platyrhynchos), American green-winged teal (Anas crecca), northern shoveler (Anas clypeata) and American wigeon (Anas americana). Based on pairwise genetic distance, highly similar LPAI genomes (>99% identity) were observed within and between species and across a range of geographic distances (up to and >1000 km), but most often between isolates collected 0-10. km apart. Highly similar viruses were detected between years, suggesting inter-annual persistence, but these were rare in our data set with the majority occurring within 0-9. days of sampling. These results identify LPAI transmission pathways in the context of species, space and time, an initial perspective into the extent of regional virus distribution and persistence, and insight into why no completely Eurasian genomes have ever been detected in Alaska. Such information will be useful in forecasting the movement of foreign-origin avian influenza strains should they be introduced to North America. ?? 2011.

Reeves, A. B.; Pearce, J. M.; Ramey, A. M.; Meixell, B. W.; Runstadler, J. A.

2011-01-01

423

Measurement of particulate concentrations produced during bulk material handling at the Tarragona harbor  

NASA Astrophysics Data System (ADS)

Bulk material handling can be a significant source of particles in harbor areas. The atmospheric impact of a number of loading/unloading activities of diverse raw materials has been assessed from continuous measurements of ambient particle concentrations recorded close to the emission sources. Two experimental campaigns have been carried out in the Tarragona port to document the impact of specific handling operations and bulk materials. Dusty bulk materials such as silica-manganese powder, tapioca, coal, clinker and lucerne were dealt with during the experiments. The highest impacts on ambient particle concentrations were recorded during handling of clinker. For this material and silica-manganese powder, high concentrations were recorded in the fine grain size (<2.5 ?m). The lowest impacts on particulate matter concentrations were recorded during handling of tapioca and lucerne, mainly in the coarse grain size (2-5-10 ?m). The effectiveness of several emission abatement measures, such as ground watering to diminish coal particle resuspension, was demonstrated to reduce ambient concentrations by up to two orders of magnitude. The importance of other good practices in specific handling operations, such as controlling the height of the shovel discharge, was also evidenced by these experiments. The results obtained can be further utilized as a useful experimental database for emission factor estimations.

Artíñano, B.; Gómez-Moreno, F. J.; Pujadas, M.; Moreno, N.; Alastuey, A.; Querol, X.; Martín, F.; Guerra, A.; Luaces, J. A.; Basora, J.

424

Application of radar to detect pedestrian workers near mining equipment.  

PubMed

Between 1990 and 1996, 133 accidents occurred and 23 mine workers were killed when haulage trucks used in surface mines collided with another smaller vehicle, a mine structure, or a pedestrian worker. These accidents were caused by a lack of visibility from the cab of the truck. Similar accidents are common with other types of equipment, such as front-end loaders and shovels. There are several methods for improving the operator's awareness of objects or people around the equipment including improved mirror designs, video cameras, and sensor technologies. Researchers at the National Institute for Occupational Safety and Health (NIOSH) are evaluating collision warning systems that are based on radar technology. These systems are mounted on the mining equipment to monitor one or more of the blind areas. An alarm is provided to the operator if an object or person enters the radar's detection area. Tests consisted of mounting the systems on a 50-ton-capacity truck typically used in quarries and a 240-ton-capacity truck used at a surface mine. This article summarizes the test procedure and results of evaluations of several off-the-shelf and prototype radar systems. False alarm rates and reliable detection zones for pedestrians were recorded for various mounting configurations on the rear of the trucks. Mounting radar systems on large equipment presents several challenges; however, the technology does show promise for this application. PMID:11504357

Ruff, T M

2001-08-01

425

Instantaneous angular speed monitoring of gearboxes under non-cyclic stationary load conditions  

NASA Astrophysics Data System (ADS)

Recent developments in the condition monitoring and asset management market have led to the commercialisation of online vibration-monitoring systems. These systems are primarily utilised to monitor large mineral mining equipment such as draglines, continuous miners and hydraulic shovels. Online monitoring systems make diagnostic information continuously available for asset management, production outsourcing and maintenance alliances with equipment manufacturers. However, most online vibration-monitoring systems are based on conventional vibration-monitoring technologies, which are prone to giving false equipment deterioration warnings on gears that operate under fluctuating load conditions. A simplified mathematical model of a gear system was developed to illustrate the feasibility of monitoring the instantaneous angular speed (IAS) as a means of monitoring the condition of gears that are subjected to fluctuating load conditions. A distinction is made between cyclic stationary load modulation and non-cyclic stationary load modulation. It is shown that rotation domain averaging will suppress the modulation caused by non-cyclic stationary load conditions but will not suppress the modulation caused by cyclic stationary load conditions. An experimental investigation on a test rig indicated that the IAS of a gear shaft could be monitored with a conventional shaft encoder to indicate a deteriorating gear fault condition.

Stander, C. J.; Heyns, P. S.

2005-07-01

426

Interspecies transmission and limited persistence of low pathogenic avian influenza genomes among Alaska dabbling ducks.  

PubMed

The reassortment and geographic distribution of low pathogenic avian influenza (LPAI) virus genes are well documented, but little is known about the persistence of intact LPAI genomes among species and locations. To examine persistence of entire LPAI genome constellations in Alaska, we calculated the genetic identities among 161 full-genome LPAI viruses isolated across 4 years from five species of duck: northern pintail (Anas acuta), mallard (Anas platyrhynchos), American green-winged teal (Anas crecca), northern shoveler (Anas clypeata) and American wigeon (Anas americana). Based on pairwise genetic distance, highly similar LPAI genomes (>99% identity) were observed within and between species and across a range of geographic distances (up to and >1000 km), but most often between isolates collected 0-10 km apart. Highly similar viruses were detected between years, suggesting inter-annual persistence, but these were rare in our data set with the majority occurring within 0-9 days of sampling. These results identify LPAI transmission pathways in the context of species, space and time, an initial perspective into the extent of regional virus distribution and persistence, and insight into why no completely Eurasian genomes have ever been detected in Alaska. Such information will be useful in forecasting the movement of foreign-origin avian influenza strains should they be introduced to North America. PMID:21964597

Reeves, Andrew B; Pearce, John M; Ramey, Andrew M; Meixell, Brandt W; Runstadler, Jonathan A

2011-12-01

427

The opossum (Didelphis virginiana) as a host for Sarcocystis debonei from cowbirds (Molothrus ater) and grackles (Cassidix mexicanus, Quiscalus quiscula).  

PubMed

Sarcocystis-infected muscles from ducks, cowbirds, and grackles were fed to cats, opossums, rats, and a dog. Only the opossum (Didelphis virginiana) was a suitable definitive host. All opossums that were fed Sarcocystis-infected cowbirds (Molothrus ater) and grackles (Cassidix mexicanus and Quiscalus quiscula) passed sporocysts in their feces. Opossums that ate the cowbirds had prepatent periods of 5 and 10 days and remained patent for at least 105 days. Opossums that ate the grackles became patent on day 10 after the infective meal and remained patent for over 90 (Quiscalus) and 105 (Cassidix) days. A single opossum fed infected muscle from a pintail duck (Anas acuta) passed sporocysts in the feces from days 13 through 18 after infection. No sporocysts were passed by opossums fed infected muscle from the green-winged teal (Anas carolinensis) and shoveller (Spatula clypeata). Sporocysts of duck, cowbird, and grackle origin were structurally similar. Mean dimensions of sporocysts were: duck-origin, 11.2 by 8.2 micron; cowbird-origin, 11.4 by 7.8 micron; Cassidix-origin, 11.2 by 7.8 micron; and Quiscalus-origin, 11.6 by 7.7 micron. We designate the sporocysts of cowbird and grackle origin as Sarcoycstis debonei Vogelsang, 1929 (Syn. Isospora boughtoni Volk, 1938). PMID:417165

Duszynski, D W; Box, E D

1978-04-01

428

The 20 April 2013 Lushan, Sichuan, mainshock, and its aftershock sequence: tectonic implications  

NASA Astrophysics Data System (ADS)

Using the double-difference relocation algorithm, we relocated the 20 April 2013 Lushan, Sichuan, earthquake ( M S 7.0), and its 4,567 aftershocks recorded during the period between 20 April and May 3, 2013. Our results showed that most aftershocks are relocated between 10 and 20 km depths, but some large aftershocks were relocated around 30 km depth and small events extended upward near the surface. Vertical cross sections illustrate a shovel-shaped fault plane with a variable dip angle from the southwest to northeast along the fault. Furthermore, the dip angle of the fault plane is smaller around the mainshock than that in the surrounding areas along the fault. These results suggest that it may be easy to generate the strong earthquake in the place having a small dip angle of the fault, which is somewhat similar to the genesis of the 2008 Wenchuan earthquake. The Lushan mainshock is underlain by the seismically anomalous layers with low-VP, low-VS, and high-Poisson's ratio anomalies, possibly suggesting that the fluid-filled fractured rock matrices might significantly reduce the effective normal stress on the fault plane to bring the brittle failure. The seismic gap between Lushan and Wenchuan aftershocks is suspected to be vulnerable to future seismic risks at greater depths, if any.

Lei, Jianshe; Zhang, Guangwei; Xie, Furen

2014-02-01

429

Lunar surface operations. Volume 3: Robotic arm for lunar surface vehicle  

NASA Astrophysics Data System (ADS)

A robotic arm for a lunar surface vehicle that can help in handling cargo and equipment, and remove obstacles from the path of the vehicle is defined as a support to NASA's intention to establish a lunar based colony by the year 2010. Its mission would include, but not limited to the following: exploration, lunar sampling, replace and remove equipment, and setup equipment (e.g. microwave repeater stations). Performance objectives for the robotic arm include a reach of 3 m, accuracy of 1 cm, arm mass of 100 kg, and lifting capability of 50 kg. The end effectors must grip various sizes and shapes of cargo; push, pull, turn, lift, or lower various types of equipment; and clear a path on the lunar surface by shoveling, sweeping aside, or gripping the obstacle present in the desired path. The arm can safely complete a task within a reasonable amount of time; the actual time is dependent upon the task to be performed. The positioning of the arm includes a manual backup system such that the arm can be safely stored in case of failure. Remote viewing and proximity and positioning sensors are incorporated in the design of the arm. The following specific topic are addressed in this report: mission and requirements, system design and integration, mechanical structure, modified wrist, structure-to-end-effector interface, end-effectors, and system controls.

Shields, William; Feteih, Salah; Hollis, Patrick

1993-07-01

430

The role of forensic geoscience in wildlife crime detection.  

PubMed

The increase in both automation and precision in the analysis of geological materials has had significant impact upon forensic investigations in the last 10 years. There is however, a fundamental philosophical difference between forensic and geological enquiry. This paper presents the results of forensic geoscientific investigations of three cases of wildlife crime. Two cases involve the analysis of soils recovered after incidents of illegal badger baiting in the United Kingdom. The third case involves the illegal importation of Eleonora's Falcon (Falco eleonorae) into the United Kingdom from the Mediterranean. All three cases utilise the analysis of soils by a variety of physical, chemical and biological techniques. These involve mineral and grain size analyses, cation and anion compositions, pH, organic content and pollen analysis. The independent analysis undertaken by specialists in each of these three main fields conclude firstly, that there is a significant similarity between sediments taken at the crime site at both badger setts and with sediments recovered from various spades, shovels and clothing belonging to suspects and secondly, that the soils analysed associated with the removal of the falcon eggs in the Mediterranean contained characteristics similar in many respects to the soils of the breeding areas of F. eleonorae on the cliffs of Mallorca. The use of these independent techniques in wildlife crime detection has great potential given the ubiquitous nature of soils and sediments found in association with wildlife sites. PMID:16875791

Morgan, Ruth M; Wiltshire, Patricia; Parker, Adrian; Bull, Peter A

2006-10-16

431

Real -time dispatching modelling for trucks with different capacities in open pit mines / Modelowanie w czasie rzeczywistym przewozów ci??arówek o ró?nej ?adowno?ci w kopalni odkrywkowej  

NASA Astrophysics Data System (ADS)

Application of fully automated systems for truck dispatching plays a major role in decreasing the transportation costs which often represent the majority of costs spent on open pit mining. Consequently, the application of a truck dispatching system has become fundamentally important in most of the world's open pit mines. Recent experiences indicate that by decreasing a truck's travelling time and the associated waiting time of its associated shovel then due to the application of a truck dispatching system the rate of production will be considerably improved. Computer-based truck dispatching systems using algorithms, advanced and accurate software are examples of these innovations. Developing an algorithm of a computer- based program appropriated to a specific mine's conditions is considered as one of the most important activities in connection with computer-based dispatching in open pit mines. In this paper the changing trend of programming and dispatching control algorithms and automation conditions will be discussed. Furthermore, since the transportation fleet of most mines use trucks with different capacities, innovative methods, operational optimisation techniques and the best possible methods for developing the required algorithm for real-time dispatching are selected by conducting research on mathematical-based planning methods. Finally, a real-time dispatching model compatible with the requirement of trucks with different capacities is developed by using two techniques of flow networks and integer programming.

Ahangaran, Daryoush Kaveh; Yasrebi, Amir Bijan; Wetherelt, Andy; Foster, Patrick

2012-10-01

432

Ground breaking at Astrotech for a new facility  

NASA Technical Reports Server (NTRS)

Dirt flies during a ground-breaking ceremony to kick off Astrotech Space Operations' construction of a new satellite preparation facility to support the Delta IV, Boeing's winning entrant in the Air Force Evolved Expendable Launch Vehicle (EELV) Program. Wielding shovels are (from left to right) Tom Alexico; Chet Lee, chairman, Astrotech Space Operations; Gen. Forrest McCartney, vice president, Launch Operations, Lockheed Martin; Richard Murphy, director, Delta Launch Operations, The Boeing Company; Keith Wendt; Toby Voltz; Loren Shriver, deputy director, Launch & Payload Processing, Kennedy Space Center; Truman Scarborough, Brevard County commissioner; U.S. Representative 15th Congressional District David Weldon; Ron Swank; and watching the action at right is George Baker, president, Astrotech Space Operations. Astrotech is located in Titusville, Fla. It is a wholly owned subsidiary of SPACEHAB, Inc., and has been awarded a 10-year contract to provide payload processing services for The Boeing Company. The facility will enable Astrotech to support the full range of satellite sizes planned for launch aboard Delta II, III and IV launch vehicles, as well as the Atlas V, Lockheed Martin's entrant in the EELV Program. The Atlas V will be used to launch satellites for government, including NASA, and commercial customers.

1999-01-01

433

The Mousterian child from Teshik-Tash is a Neanderthal: a geometric morphometric study of the frontal bone.  

PubMed

In the 1930s subadult hominin remains and Mousterian artifacts were discovered in the Teshik-Tash cave in South Uzbekistan. Since then, the majority of the scientific community has interpreted Teshik-Tash as a Neanderthal. However, some have considered aspects of the morphology of the Teshik-Tash skull to be more similar to fossil modern humans such as those represented at Skh?l and Qafzeh, or to subadult Upper Paleolithic modern humans. Here we present a 3D geometric morphometric analysis of the Teshik-Tash frontal bone in the context of developmental shape changes in recent modern humans, Neanderthals, and early modern humans. We assess the phenetic affinities of Teshik-Tash to other subadult fossils, and use developmental simulations to predict possible adult shapes. We find that the morphology of the frontal bone places the Teshik-Tash child close to other Neanderthal children and that the simulated adult shapes are closest to Neanderthal adults. Taken together with genetic data showing that Teshik-Tash carried mtDNA of the Neanderthal type, as well as its occipital bun, and its shovel-shaped upper incisors, these independent lines of evidence firmly place Teshik-Tash among Neanderthals. PMID:22976750

Gunz, Philipp; Bulygina, Ekaterina

2012-11-01

434

Recovery of Depleted Uranium Fragments from Soil  

SciTech Connect

A cost-effective method was demonstrated for recovering depleted uranium (DU) fragments from soil. A compacted clean soil pad was prepared adjacent to a pile of soil containing DU fragments. Soil from the contaminated pile was placed on the pad in three-inch lifts using conventional construction equipment. Each lift was scanned with an automatic scanning system consisting of an array of radiation detectors coupled to a detector positioning system. The data were downloaded into ArcGIS for data presentation. Areas of the pad exhibiting scaler counts above the decision level were identified as likely locations of DU fragments. The coordinates of these locations were downloaded into a PDA that was wirelessly connected to the positioning system. The PDA guided technicians to the locations where hand-held trowels and shovels were used to remove the fragments. After DU removal, the affected areas were re-scanned and the new data patched into the data base to replace the original data. This new data set along with soil sample results served as final status survey data. (authors)

Farr, C.P.; Alecksen, T.J.; Heronimus, R.S.; Simonds, M.H.; Farrar, D.R.; Baker, K.R. [Environmental Restoration Group, Inc., Washington St. NE, Albuquerque, NM (United States); Miller, M.L. [Sandia National Laboratories, Albuquerque, NM (United States)

2008-07-01

435

Cerrejon North Block project is making Colombia a major coal exporter  

SciTech Connect

The growing role of Colombia as a major supplier of internationally traded steam coal has been widely discussed in the industry. Although Colombian coal has been produced and exported in small quantities for a number of years, the country's position as a major coal exporter began in earnest in 1985 with the first commercial exports from the Cerrejon North Block Project. The mine is located on the Guajira peninsula in northeast Colombia, about 145 km (90 miles) from the coast. In addition to the mine itself, the project involves construction of a dedicated railroad and port. This forms a modern, efficient, and integrated system. The project is embodied in a 50-50 association contract between Internationl Colombia Resources (Intercor), a wholly-owned subsidiary of Exxon, and Carbocol, the Colombian state coal company. Intercor and Carbocol share investment and operating expenses equally. Intercor has the additional responsibility of managing operations on behalf of the partners. Each partner is entitled to 50% of the coal produced, and each markets its share separately. The project is a multi-seam, truck, and shovel operation, based on large reserves (2 to 3 Gt or 2.2 to 3.3 billion st) of high quality bituminous coal.

Everett, B.M.; Savage, G.D.

1986-06-01

436

[Root architecture of two desert plants in central Hexi Corridor of Northwest China].  

PubMed

In this study, the root systems of desert plant species Reaumuria soongorica and Nitraria tangutorum in the central Hexi Corridor of Northwest China were excavated by shovel, and the characteristics of the plant root architecture were analyzed by using topology and fractal theory. The root topological indices of the two desert plants were small, and the root branching patterns were herringbone-like. The roots of the two desert plants had obvious fractal characteristics, with the fractal dimension of R. soongorica and N. tangutorum being (1.18 +/- 0.04) and (1.36 +/- 0.06), respectively. The root fractal dimension and fractal abundance were significantly positively correlated with the root average link length. The root average link lengths of the two plants were long, which enlarged the plants' effective nutrition space, and thus, made the plants adapt to the dry and infertile soil environment. The sums of the root cross-sectional areas before and after the root bifurcation of the two desert plants were equal, which verified the principle of Leonardo da Vinci. A total of 17 parameters of root architecture were analyzed by the principal component analysis. The parameters of root topological structure, numbers of root links, stepwise branching ratio, and root diameter could well present the root architecture characteristics of the two desert plants. PMID:23717986

Shan, Li-Shan; Li, Yi; Ren, Wei; Su, Shi-Ping; Dong, Qiu-Lian; Geng, Dong-Mei

2013-01-01

437

Kentucky tar sand project  

SciTech Connect

Engineering details and pilot-plant results from a pioneering investigation based on a Kentucky tar-sand reserve are presented. The tar sand deposits of Kentucky are generally situated in the southeastern rim of the Illinois Basin along the southern boundary of the Western Coal Field region. In a recent study of US tar sand reserves, it was reported that over 3.4 billion barrels of oil are in Kentucky tar sand deposits alone. In the 22,000 acres, estimated reserves are over 100 million barrels of recoverable heavy oil. The oil-impregnated section of the deposit ranges in heavy oil content from five gallons per ton to over fifteen gallons per ton. The ore body is up to thirty-five feet thick and the overall stripping ratio for a commercial plant is estimated to be one cubic yard of undisturbed overburden material per ton of tar sand ore. A shovel and truck-type strip mining operation would be used to provide feedstock to the plant.

Kelley, M.N.; Jones, H.D. II; Lewis, F.W.

1985-03-01

438

Idiosyncratic Responses of High Arctic Plants to Changing Snow Regimes  

PubMed Central

The Arctic is one of the ecosystems most affected by climate change; in particular, winter temperatures and precipitation are predicted to increase with consequent changes to snow cover depth and duration. Whether the snow-free period will be shortened or prolonged depends on the extent and temporal patterns of the temperature and precipitation rise; resulting changes will likely affect plant growth with cascading effects throughout the ecosystem. We experimentally manipulated snow regimes using snow fences and shoveling and assessed aboveground size of eight common high arctic plant species weekly throughout the summer. We demonstrated that plant growth responded to snow regime, and that air temperature sum during the snow free period was the best predictor for plant size. The majority of our studied species showed periodic growth; increases in plant size stopped after certain cumulative temperatures were obtained. Plants in early snow-free treatments without additional spring warming were smaller than controls. Response to deeper snow with later melt-out varied between species and categorizing responses by growth forms or habitat associations did not reveal generic trends. We therefore stress the importance of examining responses at the species level, since generalized predictions of aboveground growth responses to changing snow regimes cannot be made.

Rumpf, Sabine B.; Semenchuk, Philipp R.; Dullinger, Stefan; Cooper, Elisabeth J.

2014-01-01

439

Lunar surface operations. Volume 3: Robotic arm for lunar surface vehicle  

NASA Technical Reports Server (NTRS)

A robotic arm for a lunar surface vehicle that can help in handling cargo and equipment, and remove obstacles from the path of the vehicle is defined as a support to NASA's intention to establish a lunar based colony by the year 2010. Its mission would include, but not limited to the following: exploration, lunar sampling, replace and remove equipment, and setup equipment (e.g. microwave repeater stations). Performance objectives for the robotic arm include a reach of 3 m, accuracy of 1 cm, arm mass of 100 kg, and lifting capability of 50 kg. The end effectors must grip various sizes and shapes of cargo; push, pull, turn, lift, or lower various types of equipment; and clear a path on the lunar surface by shoveling, sweeping aside, or gripping the obstacle present in the desired path. The arm can safely complete a task within a reasonable amount of time; the actual time is dependent upon the task to be performed. The positioning of the arm includes a manual backup system such that the arm can be safely stored in case of failure. Remote viewing and proximity and positioning sensors are incorporated in the design of the arm. The following specific topic are addressed in this report: mission and requirements, system design and integration, mechanical structure, modified wrist, structure-to-end-effector interface, end-effectors, and system controls.

Shields, William; Feteih, Salah; Hollis, Patrick

1993-01-01

440

Snow depth, soil frost and nutrient loss in a northern hardwood forest  

NASA Astrophysics Data System (ADS)

We have initiated a long-term experiment to examine the consequences of decreases in snowpack accumulation at the Hubbard Brook Experimental Forest (HBEF), a northern hardwood dominated forest located in the White Mountains of New Hampshire. We are quantifying the effects of decreases in snowpack accumulation on root dynamics of two key tree species in this forest (sugar maple, yellow birch), microbial biomass and activity, NOcation loss, the acid-base chemistry of drainage water, and soil-atmosphere trace gas fluxes. We are calibrating an existing model (SNTHERM) to depict snow depth and soil frost dynamics given past or future climate scenarios for our site. In this paper, we describe the methods we are using for the manipulation studies that began in the winter of 1997/1998 and present preliminary results from our first full year of treatment. Results from our methods development efforts show that it is possible to keep plots snow free by shovelling without disturbing the forest floor. Preliminary test plot work showed that the SNTHERM model is capable of depicting snow depth and soil temperatures in both control and manipulated plots at our site. Results from our first full year of treatment showed that a relatively mild freezing event induced significant increases in nitrogen (N) mineralization and nitrification rates, solute leaching and soil nitrous oxide production and caused significant decreases in soil methane uptake. These results suggest that soil freezing events may be major regulators of soil biogeochemical processes and solute delivery to streams in forested watersheds.

Groffman, Peter M.; Hardy, Janet P.; Nolan, Scott; Fitzhugh, Ross D.; Driscoll, Charles T.; Fahey, Timothy J.

1999-10-01

441

Parasites of waterfowl, from southwest Texas: III. The green-winged teal, Anas crecca.  

PubMed

Seventy of 72 green-winged teal, Anas crecca, from southwest Texas were infected with parasites. Seventeen species of endoparasites were recorded: Notocotylus attenuatus, Zygocotyle lunata, Typhlocoelum sisowi, Echinostoma revolutum, Hypoderaeum conoideum, Dendritobilharzia pulverulenta, Cloacotaenia megalops, Sobolevicanthus gracilis, Sobolevicanthus krabbeella, Gastrotaenia cygni, Amidostomum acutum, Amidostomum anseris, Tetrameres crami, Echinuria uncinata, Corynosoma constrictum, Polymorphus minutus. Also recorded were five species of ectoparasites: Trinoton querquedulae, Anaticola crassicornis, Anatoecous icterodes, Holomenopon setigerum and Epidermoptes sp. and the sacrosporidian, Sarcocystis rileyi. Anatoecous icterodes is a new host record for A. crecca. Sobolevicanthus gracilis, S. krabbeella, T. sisowi, and D. pulverulenta are new records for A. crecca in North America. Sobolevicanthus krabbeella is also a new record for North America. Fall juveniles had greater mean parasite intensity (29) than fall (19) and spring adults (19). Juveniles were infected with fewer species of parasites (17) than adults (20). Simpson's index was very low (0.11) indicating a diverse parasite fauna. Sorenson's index of similarity indicated that the parasite fauna for green-winged teal from southwest Texas was more similar to the shoveler's, Anas clypeata, parasites reported from southwest Texas (55%) than to green-winged teal parasites reported from eastern Canada (41%) and New Brunswick, Canada (21%). PMID:6788963

Canaris, A G; Mena, A C; Bristol, J R

1981-01-01

442

Combined microbial, seismic surveys predict oil and gas occurrences in Bolivia  

SciTech Connect

Microbial and geophysical surveys in the jungles of Bolivia's extensive Sub-Andean region have combined for three successful predictions of deep oil and gas reserves in as many tries. Hydrocarbon microseepage measured by microbial soil samples predicted the Carrasco, Katari, and Surubi structures of Bolivia's Chapare region in 1991--92, detecting traps with reserves at depths exceeding 4,500 m. Approximately 800 km of seismic lines covering 3,500 sq km was completed by Yacimientos Petroliferos Fiscales Bolivianos (YPFB) for evaluation of the YPFB reserve block. For 1 month each year at the end of the field season, seismic lines were quickly traversed by several microbial sampling teams. Using hand augers or shovels, the teams collected more than 3,200 samples approximately 20 cm (8 in.) deep at intervals of 250 m next to staked seismic locations. Microbial results were directly compared with seismic profiles for identification and ranking of traps and structures. The paper discusses the survey predictions and the microbial approach.

Lopez, J.P. (Yacimientos Petroliferos Fiscales Bolivianos, Santa Cruz (Bolivia)); Hitzman, D.; Tucker, J. (Geo-Microbial Technologies Inc., Ochelata, OK (United States))

1994-10-24

443

NACA Groundbreaking Ceremony  

NASA Technical Reports Server (NTRS)

The NACA High-Speed Flight Research Station, had initially been subordinate to the Langley Memorial Aeronautical Laboratory near Hampton, Virginia, but as the flight research in the Mojave Desert increasingly proved its worth after 1946, it made sense to make the Flight Research Station a separate entity reporting directly to the headquarters of the National Advisory Committee for Aeronautics. But an autonomous center required all the trappings of a major research facility, including good quarters. With the adoption of the Edwards 'Master Plan,' the Air Force had committed itself to moving from its old South Base to a new location midway between the South and North Bases. The NACA would have to move also--so why not take advantage of the situation and move into a full-blown research facility. The Air Force issued a lease to NACA for a location on the northwestern shore of the Roger Dry Lake. Construction started on the NACA station in early February 1953. On a windy day, January 27, 1953, at a groundbreaking ceremony stood left to right: Gerald Truszynski, Head of Instrumentation Division; Joseph Vensel, Head of the Operations Branch; Walter Williams, Head of the Station, scooping the first shovel full of dirt; Marion Kent, Head of Personnel; and California state official Arthur Samet.

1953-01-01

444

Acoustic microscopy of internal structure of resistance spot welds.  

PubMed

Acoustic microscopy, although relatively new, has many advantages within the industrial quality control process. Its high degree of sensitivity, resolution, and reliability make it ideal for use in resistance spot weld analysis, aiding in visualization of small-scale nugget failures, as well as other defects, at various depths. Acoustic microscopy makes it possible to inspect fine detail of internal structures, providing reliable inspection and characterization of weld joints. Besides weld size measurements, this technique is able to provide high resolution, three-dimensional images of the weld nuggets, revealing possible imperfections within its microstructure that may affect joint quality. The high degree of accuracy allows one to consider the results of acoustic microscopy an authoritative measure of weld size, particularly in the case of high strength steels, dual phase steel, USIBOR steel, etc. Indeed, this technique is effective even when both conventional ultrasound and hammer and chisel methods are not. In this paper, the potential of scanning acoustic microscopy as a means to provide qualitative and quantitative information about the internal microstructure of the resistance spot welds is demonstrated. Thus, acoustic microscopy is shown to be a unique and effective laboratory instrument for the evaluation and calibration of weld quality. PMID:17703655

Chertov, Andrey M; Maev, Roman G; Severin, Fedar M

2007-08-01

445

Development of a tungsten heavy alloy that fails by an adiabatic shear mechanism. Phase 1. Final report, 1 January-30 September 1992  

SciTech Connect

Kinetic Energy penetrators made from Depleted Uranium (DU) alloys have consistently performed better than equi-density and geometrically similar penetrators made from conventional tungsten heavy alloys (WHA) during ballistic penetration tests into semi-infinite Rolled Homogeneous Armor (RHA) steel targets. The superior penetration behavior of DU penetrators is presently attributed to these penetrators maintaining a chisel nose by failure along adiabatic shear bands which is in contrast to the mushroom head observed in WHA penetrators; the mushroom head decreases the energy density at the target thereby leading to reduced penetration. The radiological hazard of DU combined with chemical corrosion during storage provides an impetus to improving the state-of-the-art in WHA with respect to ballistic penetration behavior. Interestingly, WHA penetrators with DU matrix (instead of the conventional Ni-Fe, Ni-Co, or Ni-Fe-Co matrices) also fail by adiabatic shear indicating that shear localization is probably influenced greatly by matrix material properties. Hence, an investigation into alternative matrix materials for WHA that will support shear localization is warranted.

Guha, S.; Kyriacou, C.; Withers, J.C.; Loutfy, R.O.

1993-04-01

446

Chewing through the Miocene: an examination of the feeding musculature in the ground sloth Hapalops from South America (Mammalia: Pilosa)  

PubMed Central

Hapalops, a smaller-sized and early sloth of the Megatheroidea, appeared in the middle Miocene Santa Cruz formation of Argentina. This genus is part of the group from which later, larger megatheroids arose, i.e., Nothrotheriops and Megatherium. Many cranial characters support this idea; however Hapalops is not merely a smaller antecedent of the later forms. Specifically, Hapalops retains short anterior caniniform teeth, and a temporomandibular joint elevated above the cheek tooth row; a combination distinct among sloths. An elevated temporomandibular joint occurs in Bradypus, a tree sloth with anterior chisel-shaped teeth instead of caniniforms, and the tree sloth Choloepus, which is aligned with the megalonychids, has anterior caniniforms. Hapalops has an elongated zygomatic ascending process that is reminiscent of that in Bradypus; however, the Bradypus skull is extremely foreshortened while that of Hapalops is elongated, as in nothrotheres, but not deepened as in megatheres. Previous work identified many sloth cranial character complexes, and functional limitations on skull feature combinations. The unique Hapalops character patterns indicate a selective feeder with a mediolaterally oriented grinding stroke during mastication.

Naples, Virginia L.; McAfee, Robert K.

2014-01-01

447

Sparks begin to fly in nonconventional friction welding and surfacing  

SciTech Connect

A technology with enormous potential for welding and surfacing is the linear or consumable-rod friction welding process. The jet engine manufacturers are interested in the process both for welding and surfacing of alloys and materials that would be difficult to handle by any other means. In most present engines, slots are provided in the disks in order to accept the turbine blades. So, when a blade becomes worn or damaged, it is removed and a replacement blade is inserted in its place. In the new BLISK or bladed disk design of engines, the blades will be integral parts of the engine. Linear friction welding could play a major role in the manufacture and repair of engines of BLISK design. The new design is expected to improve engine performance significantly. According to TWI, potential applications for linear friction welding include gears, turbine wheels, chain links, electrical bus bar components, such plastic automotive parts as bumpers, boot lids and floor pans, bimetallic chisel blades, and multiple joints in metals or plastics. This paper discusses some of the research done by various companies into the newer variations of friction welding.

Irving, B.

1993-05-01

448

Modeling soil organic matter dynamics as affected by soil water erosion.  

PubMed

Soil organic carbon (SOC) stock is an important component of the global carbon (C) cycle, which has the potential to influence global climate. In this paper we presented an overview of soil organic matter (SOM) models in the context of soil erosion and discussed basic processes driving erosion-induced SOC loss. Although the mechanism of this loss is poorly understood, erosion influences SOC in two ways: redistribution of C within the watershed or ecosystem, and loss of C to the atmosphere. Erosion disperses soil, altering its microbiological activity as well as water, air and nutrient regimes. This, along with sediment enrichment, has an impact on greenhouse gas emission from soil. For most of agricultural settings, field studies suggest that cultivation along with soil erosion are the primary reasons for SOC loss. Tracing the fate of eroded C is a challenging task. Modeling is the approach taken most often. In this paper we discuss approaches used in various SOC models to assess erosion-induced C loss from soil in agricultural ecosystems. An example with Century model applied to meadow and corn-soybean rotation under chisel-till demonstrated the model's ability to respond well to different erosion scenarios. It was estimated that at soil loss rate of 10 t ha(-1) year(-1) (value often considered a threshold for maintaining productivity) 19% of the total SOC loss would be attributed to erosion after 90 years of cultivation. PMID:15031015

Polyakov, V; Lal, R

2004-06-01

449

Chewing through the Miocene: an examination of the feeding musculature in the ground sloth Hapalops from South America (Mammalia: Pilosa).  

PubMed

Hapalops, a smaller-sized and early sloth of the Megatheroidea, appeared in the middle Miocene Santa Cruz formation of Argentina. This genus is part of the group from which later, larger megatheroids arose, i.e., Nothrotheriops and Megatherium. Many cranial characters support this idea; however Hapalops is not merely a smaller antecedent of the later forms. Specifically, Hapalops retains short anterior caniniform teeth, and a temporomandibular joint elevated above the cheek tooth row; a combination distinct among sloths. An elevated temporomandibular joint occurs in Bradypus, a tree sloth with anterior chisel-shaped teeth instead of caniniforms, and the tree sloth Choloepus, which is aligned with the megalonychids, has anterior caniniforms. Hapalops has an elongated zygomatic ascending process that is reminiscent of that in Bradypus; however, the Bradypus skull is extremely foreshortened while that of Hapalops is elongated, as in nothrotheres, but not deepened as in megatheres. Previous work identified many sloth cranial character complexes, and functional limitations on skull feature combinations. The unique Hapalops character patterns indicate a selective feeder with a mediolaterally oriented grinding stroke during mastication. PMID:25075299

Naples, Virginia L; McAfee, Robert K

2014-01-01

450

Under-ice noise generated from diamond exploration in a Canadian sub-arctic lake and potential impacts on fishes.  

PubMed

Mineral exploration is increasing in Canada, particularly in the north where extensive diamond mining and exploration are occurring. This study measured the under-ice noise produced by a variety of anthropogenic sources (drilling rigs, helicopters, aircraft landing and takeoff, ice-road traffic, augers, snowmobiles, and chisels) at a winter-based diamond exploration project on Kennady Lake in the Northwest Territories, Canada to infer the potential impact of noise on fishes in the lake. The root-mean-square noise level measured 5 m from a small diameter drill was approximately 46 dB greater (22 kHz bandwidth) than ambient noise, while the acoustic particle velocity was approximately 40 dB higher than ambient levels. The loudest sounds at the exploration site were produced by ice cracking, both natural and during landing and takeoff of a C130 Hercules aircraft. However, even walking on the snow above the ice raised ambient sound levels by approximately 30 dB. Most of the anthropogenic sounds are likely detectable by fishes with hearing specializations, such as chubs and suckers. Other species without specialized hearing adaptations will detect these sounds only close to the source. The greatest potential impact of noise from diamond exploration is likely to be the masking of sounds for fishes with sensitive hearing. PMID:19894802

Mann, D; Cott, P; Horne, B

2009-11-01

451

A coiled-coil-repeat protein 'Ccrp' in Bdellovibrio bacteriovorus prevents cellular indentation, but is not essential for vibroid cell morphology.  

PubMed

Bdellovibrio bacteriovorus are small, vibroid, predatory bacteria that grow within the periplasmic space of a host Gram-negative bacterium. The intermediate-filament (IF)-like protein crescentin is a member of a broad class of IF-like, coiled-coil-repeat-proteins (CCRPs), discovered in Caulobacter crescentus, where it contributes to the vibroid cell shape. The B. bacteriovorus genome has a single ccrp gene encoding a protein with an unusually long, stutter-free, coiled-coil prediction; the inactivation of this did not alter the vibriod cell shape, but caused cell deformations, visualized as chiselled insets or dents, near the cell poles and a general 'creased' appearance, under the negative staining preparation used for electron microscopy, but not in unstained, frozen, hydrated cells. Bdellovibrio bacteriovorus expressing 'teal' fluorescent protein (mTFP), as a C-terminal tag on the wild-type Ccrp protein, did not deform under negative staining, suggesting that the function was not impaired. Localization of fluorescent Ccrp-mTFP showed some bias to the cell poles, independent of the cytoskeleton, as demonstrated by the addition of the MreB-specific inhibitor A22. We suggest that the Ccrp protein in B. bacteriovorus contributes as an underlying scaffold, similar to that described for the CCRP protein FilP in Streptom