Access to edge scenarios for testing a scraper element in early operation phases of Wendelstein 7-X

DOE PAGES

Holbe, H.; Pedersen, T. Sunn; Geiger, J.; ...

2016-01-29

The edge topology of magnetic fusion devices is decisive for the control of the plasma exhaust. In Wendelstein 7-X, the island divertor concept will be used, for which the edge topology can change significantly as the internal currents in a plasma discharge evolve towards steady-state. Consequently, the device has been optimized to minimize such internal currents, in particular the bootstrap current [1]. Nonetheless, there are predicted pulse scenarios where effects of the remaining internal currents could potentially lead to overload of plasma-facing components. These internal currents are predicted to evolve on long time scales (tens of seconds) so their effectsmore » on the edge topology and the divertor heat loads may not be experimentally accessible in the first years of W7-X operation, where only relatively short pulses are possible. However, we show here that for at least one important long-pulse divertor operation issue, relevant physics experiments can be performed already in short-pulse operation, through judicious adjustment of the edge topology by the use of the existing coil sets. The specific issue studied here is a potential overload of the divertor element edges. This overload might be mitigated by the installation of an extra set of plasma-facing components, so-called scraper elements, as suggested in earlier publications. It is shown here that by a targeted control of edge topology, the effectiveness of such scraper elements can be tested already with uncooled test-scraper elements in short-pulse operation. Furthermore, this will allow an early and well-informed decision on whether long-pulse-capable (actively cooled) scraper elements should be built and installed.« less

Tongue scraping for treating halitosis.

PubMed

Outhouse, T L; Al-Alawi, R; Fedorowicz, Z; Keenan, J V

2006-04-19

Halitosis is used to describe any disagreeable odour of expired air regardless of its origin. Mouthwashes which disguise oral malodor are more socially acceptable and generally more popular than tongue scrapers. To provide reliable evidence regarding the effectiveness of tongue scraping versus other interventions (including mouthwashes) to control halitosis. We searched the following databases: Cochrane Oral Health Group Trials Register (to 15th September 2005); the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3 2005); MEDLINE 1966 to September Week 1 2005; EMBASE 1974 to September 2005 (searched September 19th 2005). Randomized controlled trials comparing different methods of tongue cleaning to reduce mouth odour in adults with halitosis. Clinical heterogeneity between the two included trials precluded pooling of data, therefore a descriptive summary is presented. This review included two trials involving 40 participants. Both trials were methodologically sound but included no data for the primary outcomes specified in this review. Secondary outcomes expressed as volatile sulfur compound (VSC) levels were assessed by a portable sulfide monitor in both trials. One trial showed reductions of VSC levels of 42% with the tongue cleaner, 40% with the tongue scraper and 33% with the toothbrush. Reduced VSC levels persisted longer with the tongue cleaner than the toothbrush and could not be detected for more than 30 minutes after the intervention in any of the groups. Differences were assessed by the Friedman and Wilcoxon signed rank tests with the level of significance set at P < 0.05. The second trial, in which differences in totaled rank values between groups were compared by the Dunn method alpha = 0.01, showed a reduction of VSC levels compared with baseline measurements of 75% with the tongue scraper and 45% with the toothbrush. Adverse effects in one trial were nausea (60%) and trauma (10%) with the toothbrush and all participants receptive to using the tongue scraper. Based on the independent data from these two trials there was a statistically significant difference between the effectiveness of either the tongue cleaner or the tongue scraper in reducing VSC levels when compared with the toothbrush. There is weak and unreliable evidence to show that there is a small but statistically significant difference in reduction of VSC levels when tongue scrapers or cleaners rather than toothbrushes are used to reduce halitosis in adults. We found no high level evidence comparing mechanical with other forms of tongue cleaning.

Overview of design and analysis activities for the W7-X scraper element

DOE PAGES

Lumsdaine, A.; Bjorholm, T.; Harris, J.; ...

2016-08-18

The Wendelstein 7-X stellarator is in final stages of commissioning, and will begin operation in late 2015. In the first phase, the machine will operate with a limiter, and will be restricted to low power and short pulse. But in 2019, plans are for an actively cooled divertor to be installed, and the machine will operate in steady state at full power. Recently, plasma simulations have indicated that, in this final operational phase, a bootstrap current will evolve in certain scenarios. This will cause the sensitive ends of the divertor target to be overloaded beyond their qualified limit. A highmore » heat flux scraper element (HHF-SE) has been proposed in order to take up some of the convective flux and reduce the load on the divertor. In order to examine whether the HHF-SE will be able to effectively reduce the plasma flux in the divertor region of concern, and to determine how the pumping effectiveness will be affected by such a component, it is planned to include a test divertor unit scraper element (TDU-SE) in 2017 during an earlier operational phase. Several U.S. fusion energy science laboratories have been involved in the design, analysis (structural and thermal finite element, as well as computational fluid dynamics), plasma simulation, planning, prototyping, and diagnostic development around the scraper element program (both TDU-SE and HHF-SE). As a result, this paper presents an overview of all of these activities and their current status.« less

Arrangement for controlled engagement of the tools of a mining machine with a mine face

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

Blumenthal, G.; Bollmann, A.

1981-07-28

An arrangement for controlled engagement of the tools of a coal planer, with a mine face comprises a scraper conveyor, provided on its front face directed toward the mine face with a guide rail guiding the coal planer for reciprocation along the mine face and a mechanism for tilting the conveyor and the coal planer about a substantially horizontal axis. The tilting mechanism is connected to the rear face of the conveyor and extends in its entirety rearwardly of the rear face of the latter. The tilting mechanism comprises a guide linkage pivotally connected at its front end to themore » rear face of the scraper conveyor while its rear end portion forms a housing for a fluid operated cylinder and piston unit, the piston rod of which is connected to a connecting rod guided by the guide linkage for movement in longitudinal direction and having an upwardly extending front section pivotally connected at its upper free end to the rear face of the scraper conveyor. The fluid operated cylinder-and-piston unit is thus considerably spaced from the scraper conveyor and the material transported thereby and especially coal dust raised during transport of the mined coal by the conveyor, whereby maintenance of the tilting unit is reduced. The guide linkage, the connecting rod and the tilting unit are all in close vicinity to the sole of the mine gallery to leave a considerable free space between the arrangement and the roof of the mine gallery.« less

Active heat exchange system development for latent heat thermal energy storage

NASA Technical Reports Server (NTRS)

Alario, J.; Haslett, R.

1980-01-01

Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application. Two concepts selected for hardware development are a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which has been nickel plated to decrease adhesion forces. Suitable phase change material (PCM) storage media with melting points in the temperature range of interest (250 C to 400 C) were investigated. The specific salt recommended for laboratory tests was a chloride eutectic (20.5KCl-24/5 NaCl-55.0MgCl 2% by wt.), with a nominal melting point of 385 C.

Quantifying microwear on experimental Mistassini quartzite scrapers: preliminary results of exploratory research using LSCM and scale-sensitive fractal analysis.

PubMed

Stemp, W James; Lerner, Harry J; Kristant, Elaine H

2013-01-01

Although previous use-wear studies involving quartz and quartzite have been undertaken by archaeologists, these are comparatively few in number. Moreover, there has been relatively little effort to quantify use-wear on stone tools made from quartzite. The purpose of this article is to determine the effectiveness of a measurement system, laser scanning confocal microscopy (LSCM), to document the surface roughness or texture of experimental Mistassini quartzite scrapers used on two different contact materials (fresh and dry deer hide). As in previous studies using LSCM on chert, flint, and obsidian, this exploratory study incorporates a mathematical algorithm that permits the discrimination of surface roughness based on comparisons at multiple scales. Specifically, we employ measures of relative area (RelA) coupled with the F-test to discriminate used from unused stone tool surfaces, as well as surfaces of quartzite scrapers used on dry and fresh deer hide. Our results further demonstrate the effect of raw material variation on use-wear formation and its documentation using LSCM and RelA. © Wiley Periodicals, Inc.

Active heat exchange system development for latent heat thermal energy storage

NASA Technical Reports Server (NTRS)

Alario, J.; Kosson, R.; Haslett, R.

1980-01-01

Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application (300 MW sub t storage for 6 hours). Two concepts were selected for hardware development: (1) a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and (2) a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which was nickel plated to decrease adhesion forces. In addition to improving performance by providing a nearly constant transfer rate during discharge, these active heat exchanger concepts were estimated to cost at least 25% less than the passive tube-shell design.

Predetermined Flake Production at the Lower/Middle Paleolithic Boundary: Yabrudian Scraper-Blank Technology

PubMed Central

Shimelmitz, Ron; Kuhn, Steven L.; Ronen, Avraham; Weinstein-Evron, Mina

2014-01-01

While predetermined débitage technologies are recognized beginning with the middle Acheulian, the Middle Paleolithic is usually associated with a sharp increase in their use. A study of scraper-blank technology from three Yabrudian assemblages retrieved from the early part of the Acheulo-Yabrudian complex of Tabun Cave (ca. 415–320 kyr) demonstrates a calculated and preplanned production, even if it does not show the same complexity and elaboration as in the Levallois technology. These scraper dominated assemblages show an organization of production based on an intensive use of predetermination blank technology already in place at the end of the Lower Paleolithic of the Levant. These results provide a novel perspective on the differences and similarities between the Lower and Middle Paleolithic industries. We suggest that there was a change in the paradigm in the way hominins exploited stone tools: in many Middle Paleolithic assemblages the potential of the stone tools for hafting was a central feature, in the Lower Paleolithic ergonometric considerations of manual prehension were central to the design of blanks and tools. PMID:25192429

Effect of root planing on surface topography: an in-vivo randomized experimental trial.

PubMed

Rosales-Leal, J I; Flores, A B; Contreras, T; Bravo, M; Cabrerizo-Vílchez, M A; Mesa, F

2015-04-01

The root surface topography exerts a major influence on clinical attachment and bacterial recolonization after root planing. In-vitro topographic studies have yielded variable results, and clinical studies are necessary to compare root surface topography after planing with current ultrasonic devices and with traditional manual instrumentation. The aim of this study was to compare the topography of untreated single-rooted teeth planed in vivo with a curette, a piezoelectric ultrasonic (PU) scraper or a vertically oscillating ultrasonic (VOU) scraper. In a randomized experimental trial of 19 patients, 44 single-rooted teeth were randomly assigned to one of four groups for: no treatment; manual root planing with a curette; root planing with a PU scraper; or root planing with a VOU scraper. Post-treatment, the teeth were extracted and their topography was analyzed in 124 observations with white-light confocal microscopy, measuring the roughness parameters arithmetic average height, root-mean-square roughness, maximum height of peaks, maximum depth of valleys, absolute height, skewness and kurtosis. The roughness values arithmetic average height and root-mean-square roughness were similar after each treatment and lower than after no treatment ( p < 0.05). Absolute height was lower in the VOU group than in the untreated ( p = 0.0026) and PU (p = 0.045) groups. Surface morphology was similar after the three treatments and was less irregular than in the untreated group. Values for the remaining roughness parameters were similar among all treatment groups ( p > 0.05). Both ultrasonic devices reduce the roughness, producing a similar topography to that observed after manual instrumentation with a curette, to which they appear to represent a valid alternative. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Exposure to whole-body vibration and seat transmissibility in a large sample of earth scrapers.

PubMed

Salmoni, Alan; Cann, Adam; Gillin, Kent

2010-01-01

It is often difficult to access a large sample of vehicles in various work environments to evaluate worker exposure to vibration such as in construction and mining. Thus the main purpose of the present research was to test vibration exposure in a relatively large number of earth scrapers. The second aim was to assess vibration exposure values on seat transmissibility. 33earth scrapers were assessed for both exposure to whole-body vibration and seat transmissibility. Two triaxial accelerometers, one placed on the seat and one on the floor directly below the seat, were used to gather whole-body vibration values (a(w)). Each machine was tested for a minimum of three complete work cycles: idling, scraping, travelling full, dumping, travelling empty back to the scrape site. Results showed that idling and scraping produced low levels of vibration when compared to travelling and dumping. Second, when the a(w) values were compared to the EU safety standards for an eight hour work day, the data (z axis) exceeded the exposure action value (0.5 m/s2) in all machines, and the exposure limit value (1.15 m/s2) in some. Implications; Operators of the scrapers were being exposed to unsafe levels of whole-body vibration. When the seats were assessed to see whether they were attenuating operator exposure to vibration, many of the seat effective amplitude transmissibility (SEAT) values exceeded 1.0. This meant that some of the seats were actually amplifying the vibration present at the floor, particularly in the y axis. Travelways should be kept smooth, operating speeds reduced, and new seats, effective in all three axes, designed.

Experimental assessment of advanced Stirling component concepts

NASA Technical Reports Server (NTRS)

Ziph, B.

1985-01-01

The results of an experimental assessment of some advanced Stirling engine component concepts are presented. High performance piston rings, reciprocating oil scrapers and heat pipes with getters and with mechanical couplings were tested. The tests yielded the following results: (1) Bonded, split, pumping piston rings, in preliminary testing, proved a promising concept, exhibiting low leakage and friction losses. Solid piston rings proved impractical in view of their sensitivity to the operating temperature; (2) A babbit oil scraper in a compliant housing performed well in atmospheric endurance testing. In pressurized tests the scraper did not perform well as a containment seal. The latter tests suggest modifications which may adapt Ti successfully to that application; and (3) Heat pipe endurance tests indicated the adequacy of simple, inexpensive fabrication and filling procedures. Getters were provided to increase the tolerance of the heat pipes to the presence of air and commercially available couplings were demonstrated to be suitable for heat pipe application. In addition to the above tests, the program also included a design effort for a split shaft applicable to a swashplate driven engine with a pressurized crank-case. The design is aimed, and does accomplish, an increase in component life to more than 10,000 hours.

Prototyping phase of the high heat flux scraper element of Wendelstein 7-X

DOE PAGES

Boscary, Jean; Greuner, Henri; Ehrke, G.; ...

2016-03-24

The water-cooled high heat flux scraper element aims to reduce excessive heat loads on the target element ends of the actively cooled divertor of Wendelstein 7-X. Its purpose is to intercept some of the plasma fluxes both upstream and downstream before they reach the divertor surface. The scraper element has 24 identical plasma facing components (PFCs) divided into 6 modules. One module has 4 PFCs hydraulically connected in series by 2 water boxes. A PFC, 247 mm long and 28 mm wide, has 13 monoblocks made of CFC NB31 bonded by hot isostatic pressing onto a CuCrZr cooling tube equippedmore » with a copper twisted tape. 4 full-scale prototypes of PFCs have been successfully tested in the GLADIS facility up to 20 MW/m 2. The difference observed between measured and calculated surface temperatures is probably due to the inhomogeneity of CFC properties. The design of the water box prototypes has been detailed to allow the junction between the cooling pipe of the PFCs and the water boxes by internal orbital welding. In conclusion, the prototypes are presently under fabrication.« less

New host records of monacanthid fish for three Kudoa spp. (K. septempunctata, K. thyrsites, and K. shiomitsui) prevalent in the olive flounder (Paralichthys olivaceus), with the description of K. parathyrsites n. sp. from a black scraper (Thamnaconus modestus).

PubMed

Kasai, Akihiro; Li, Ying-Chun; Mafie, Eliakunda; Sato, Hiroshi

2016-07-01

Kudoa septempunctata (Myxosporean: Multivalvulida) is known as a cause of foodborne disease associated with consumption of raw flesh of the olive flounder (Paralichthys olivaceus). Knowledge of its life cycle, particularly alternate annelid hosts and reservoirs or susceptible fish hosts in natural waters, may facilitate disease control in aquaculture farms. Our recent survey of myxosporean infection in monacanthid fish in natural waters around Japan revealed infection with three kudoid species prevalent in the olive flounder, i.e., K. septempunctata, Kudoa thyrsites, and Kudoa shiomitsui. Of the 51 black scrapers (Thamnaconus modestus) examined, five fish were infected: two fish with K. septempunctata and three with K. thyrsites. One of the fish infected with K. septempunctata was also infected with a K. thyrsites-like species. One of the 17 threadsail filefish (Stephanolepis cirrhifer) and two of four unicorn leatherjackets (Aluterus monoceros) were parasitized with K. shiomitsui. Three modest filefish (Thamnaconus modestoides) had no kudoid infection. K. septempunctata from a black scraper fished in the Inland Sea of Japan off Yamaguchi had 6-8 (predominantly 7) shell valves/polar capsules, whereas K. septempunctata found in another black scraper from the Sea of Japan off Tottori had 5 or 6 (predominantly 6). However, the two isolates displayed identical 18S and 28S ribosomal RNA gene (rDNA) nucleotide sequences, which were also identical to the isolates from the olive flounder. K. thyrsites from the Inland Sea of Japan off Yamaguchi and Sea of Japan off Tottori and K. shiomitsui from the Sea of Japan off Shimane and western Pacific Ocean off Kochi were also morphologically and genetically characterized. They were found to be coincident with the previous reports from olive flounders. Furthermore, the K. thyrsites-like species found in a black scraper from the Inland Sea of Japan off Yamaguchi was morphologically and genetically characterized; a new species, Kudoa parathyrsites n. sp., is erected for this species. The relationships of the new species with K. thyrsites and related species as well as those of K. shiomitsui with Kudoa pericardialis and related species parasitizing the pericardium are briefly discussed.

Overall Performance Evaluation of Tubular Scraper Conveyors Using a TOPSIS-Based Multiattribute Decision-Making Method

PubMed Central

Yao, Yanping; Kou, Ziming; Meng, Wenjun; Han, Gang

2014-01-01

Properly evaluating the overall performance of tubular scraper conveyors (TSCs) can increase their overall efficiency and reduce economic investments, but such methods have rarely been studied. This study evaluated the overall performance of TSCs based on the technique for order of preference by similarity to ideal solution (TOPSIS). Three conveyors of the same type produced in the same factory were investigated. Their scraper space, material filling coefficient, and vibration coefficient of the traction components were evaluated. A mathematical model of the multiattribute decision matrix was constructed; a weighted judgment matrix was obtained using the DELPHI method. The linguistic positive-ideal solution (LPIS), the linguistic negative-ideal solution (LNIS), and the distance from each solution to the LPIS and the LNIS, that is, the approximation degrees, were calculated. The optimal solution was determined by ordering the approximation degrees for each solution. The TOPSIS-based results were compared with the measurement results provided by the manufacturer. The ordering result based on the three evaluated parameters was highly consistent with the result provided by the manufacturer. The TOPSIS-based method serves as a suitable evaluation tool for the overall performance of TSCs. It facilitates the optimal deployment of TSCs for industrial purposes. PMID:24991646

Response of herbivore functional groups to sequential perturbations in Moorea, French Polynesia

NASA Astrophysics Data System (ADS)

Han, Xueying; Adam, Thomas C.; Schmitt, Russell J.; Brooks, Andrew J.; Holbrook, Sally J.

2016-09-01

The reefs surrounding the island of Moorea, French Polynesia, experienced two large pulse perturbations between 2008 and 2010, an outbreak of the crown-of-thorns seastar ( Acanthaster planci) followed by a cyclone, that resulted in the reduction in live coral cover on the fore reef from ~40 to <5 %. Live coral cover in back reef and fringing reef habitats initially remained relatively stable, but began a gradual decline around 2010. We assessed the changes in the functional composition of the herbivorous fish community following the pulse perturbations and during the time of gradual coral decline on the back reef and fringing reef. Forty-nine species of herbivorous fishes quantified in yearly surveys between 2006 and 2014 were assigned to six functional groups: browser, detritivore, excavator, farmer, grazer/detritivore, and scraper. Non-metric multidimensional scaling analyses revealed that despite unique functional assemblages initially existing among the fringing reef, back reef, and fore reef habitats, the herbivorous fish communities in all three habitats responded in a qualitatively similar fashion to coral decline by moving toward functional communities characterized by an increased representation of excavators and scrapers. Island-wide scraper biomass increased by ~sevenfold in the post-disturbance time period, while excavator biomass increased by nearly threefold. The biomass of detritivores and grazers/detritivores also increased over the same time period, but to a much lesser degree, while the biomass of browsers and farmers remained essentially unchanged. Macroalgae remained a relatively minor space holder (<10 % cover) in lagoon habitats and on the fore reef through 2014, enabling recruitment of juvenile coral and initiating coral recovery on the fore reef. Results suggest that a functional community with a substantial biomass of herbivores and the capacity for the biomass of scrapers and excavators to increase rapidly in response to landscape-scale declines in coral cover may enhance resilience by preventing the widespread establishment of macroalgae.

Untethered Crewlock Bag Drifts Away from ISS

NASA Image and Video Library

2008-11-18

S126-E-008155 (18 Nov. 2008) --- An extravehicular activity (EVA) tool bag drifts away from the International Space Station during the mission's first scheduled spacewalk for STS-126. About halfway into the spacewalk, one of the grease guns that astronaut Heidemarie Stefanyshyn-Piper (out of frame), mission specialist, was preparing to use on the Solar Alpha Rotary Joint released some Braycote grease into her crew lock bag, which is the tool bag the spacewalkers use during their activities. As she was cleaning the inside of the bag, it drifted away from her and toward the aft and starboard portion of the International Space Station. Inside the bag were two grease guns, a scraper, a scraper debris container, several wipes in a caddy and tethers.

Untethered Crewlock Bag Drifts Away from ISS

NASA Image and Video Library

2008-11-18

S126-E-008143 (18 Nov. 2008) --- An extravehicular activity (EVA) tool bag drifts away from the International Space Station during the mission's first scheduled spacewalk for STS-126. About halfway into the spacewalk, one of the grease guns that astronaut Heidemarie Stefanyshyn-Piper (out of frame), mission specialist, was preparing to use on the Solar Alpha Rotary Joint released some Braycote grease into her crew lock bag, which is the tool bag the spacewalkers use during their activities. As she was cleaning the inside of the bag, it drifted away from her and toward the aft and starboard portion of the International Space Station. Inside the bag were two grease guns, a scraper, a scraper debris container, several wipes in a caddy and tethers.

Untethered Crewlock Bag Drifts Away from ISS

NASA Image and Video Library

2008-11-18

S126-E-008146 (18 Nov. 2008) --- An extravehicular activity (EVA) tool bag drifts away from the International Space Station during the mission's first scheduled spacewalk for STS-126. About halfway into the spacewalk, one of the grease guns that astronaut Heidemarie Stefanyshyn-Piper (out of frame), mission specialist, was preparing to use on the Solar Alpha Rotary Joint released some Braycote grease into her crew lock bag, which is the tool bag the spacewalkers use during their activities. As she was cleaning the inside of the bag, it drifted away from her and toward the aft and starboard portion of the International Space Station. Inside the bag were two grease guns, a scraper, a scraper debris container, several wipes in a caddy and tethers.

30 CFR 77.1607 - Loading and haulage equipment; operation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... to vehicular traffic. (p) Dippers, buckets, scraper blades, and similar movable parts shall be... to prevent conveyors from running in reverse if a hazard to personnel would be caused. (ee) Aerial...

30 CFR 77.1607 - Loading and haulage equipment; operation.

Code of Federal Regulations, 2012 CFR

2012-07-01

... to vehicular traffic. (p) Dippers, buckets, scraper blades, and similar movable parts shall be... to prevent conveyors from running in reverse if a hazard to personnel would be caused. (ee) Aerial...

30 CFR 77.1607 - Loading and haulage equipment; operation.

Code of Federal Regulations, 2013 CFR

2013-07-01

... to vehicular traffic. (p) Dippers, buckets, scraper blades, and similar movable parts shall be... to prevent conveyors from running in reverse if a hazard to personnel would be caused. (ee) Aerial...

30 CFR 77.1607 - Loading and haulage equipment; operation.

Code of Federal Regulations, 2014 CFR

2014-07-01

... to vehicular traffic. (p) Dippers, buckets, scraper blades, and similar movable parts shall be... to prevent conveyors from running in reverse if a hazard to personnel would be caused. (ee) Aerial...

30 CFR 77.1607 - Loading and haulage equipment; operation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... to vehicular traffic. (p) Dippers, buckets, scraper blades, and similar movable parts shall be... to prevent conveyors from running in reverse if a hazard to personnel would be caused. (ee) Aerial...

How to deal with morning bad breath: A randomized, crossover clinical trial.

PubMed

Oliveira-Neto, Jeronimo M; Sato, Sandra; Pedrazzi, Vinícius

2013-11-01

The absence of a protocol for the treatment of halitosis has led us to compare mouthrinses with mechanical oral hygiene procedures for treating morning breath by employing a hand-held sulfide monitor. To compare the efficacy of five modalities of treatment for controlling morning halitosis in subjects with no dental or periodontal disease. This is a five-period, randomized, crossover clinical trial. Twenty volunteers were randomly assigned to the trial. Testing involved the use of a conventional tongue scraper, a tongue scraper joined to the back of a toothbrush's head, two mouthrinses (0.05% cetylpyridinium chloride and 0.12% chlorhexidine digluconate) and a soft-bristled toothbrush and fluoride toothpaste for practicing oral hygiene. Data analysis was performed using SPSS version 17 for Windows and NCSS 2007 software (P < 0.05). The products and the periods were compared with each other using the Friedman's test. When significant differences (P < 0.05) were determined, the products and periods were compared in pairs by using the Wilcoxon's test and by adjusting the original significance level (0.05) for multiple comparisons by using the Bonferroni's method. The toothbrush's tongue scraper was able to significantly reduce bad breath for up to 2 h. Chlorhexidine reduced bad breath only at the end of the second hour, an effect that lasted for 3 h. Mechanical tongue cleaning was able to immediately reduce bad breath for a short period, whereas chlorhexidine and mechanical oral hygiene reduced bad breath for longer periods, achieving the best results against morning breath.

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

Lumsdaine, A.; Bjorholm, T.; Harris, J.

The Wendelstein 7-X stellarator is in final stages of commissioning, and will begin operation in late 2015. In the first phase, the machine will operate with a limiter, and will be restricted to low power and short pulse. But in 2019, plans are for an actively cooled divertor to be installed, and the machine will operate in steady state at full power. Recently, plasma simulations have indicated that, in this final operational phase, a bootstrap current will evolve in certain scenarios. This will cause the sensitive ends of the divertor target to be overloaded beyond their qualified limit. A highmore » heat flux scraper element (HHF-SE) has been proposed in order to take up some of the convective flux and reduce the load on the divertor. In order to examine whether the HHF-SE will be able to effectively reduce the plasma flux in the divertor region of concern, and to determine how the pumping effectiveness will be affected by such a component, it is planned to include a test divertor unit scraper element (TDU-SE) in 2017 during an earlier operational phase. Several U.S. fusion energy science laboratories have been involved in the design, analysis (structural and thermal finite element, as well as computational fluid dynamics), plasma simulation, planning, prototyping, and diagnostic development around the scraper element program (both TDU-SE and HHF-SE). As a result, this paper presents an overview of all of these activities and their current status.« less

Tongue Scrapers Only Slightly Reduce Bad Breath

MedlinePlus

... information you need from the Academy of General Dentistry Friday, June 29, 2018 About | Contact InfoBites Quick ... study in the September/October issue of General Dentistry, the Academy?xml:namespace> of General Dentistry?xml: ...

29 CFR 1926.1001 - Minimum performance criteria for rollover protective structures for designated scrapers, loaders...

Code of Federal Regulations, 2013 CFR

2013-07-01

... of Steel Products (available at each Regional Office of the Occupational Safety and Health... Society of Automotive Engineers Recommended Practices: SAE J320a, Minimum Performance Criteria for Roll...

29 CFR 1926.1001 - Minimum performance criteria for rollover protective structures for designated scrapers, loaders...

Code of Federal Regulations, 2014 CFR

2014-07-01

... of Steel Products (available at each Regional Office of the Occupational Safety and Health... Society of Automotive Engineers Recommended Practices: SAE J320a, Minimum Performance Criteria for Roll...

29 CFR 1926.1001 - Minimum performance criteria for rollover protective structures for designated scrapers, loaders...

Code of Federal Regulations, 2010 CFR

2010-07-01

... of Steel Products (available at each Regional Office of the Occupational Safety and Health... Society of Automotive Engineers Recommended Practices: SAE J320a, Minimum Performance Criteria for Roll...

29 CFR 1926.1001 - Minimum performance criteria for rollover protective structures for designated scrapers, loaders...

Code of Federal Regulations, 2011 CFR

2011-07-01

... of Steel Products (available at each Regional Office of the Occupational Safety and Health... Society of Automotive Engineers Recommended Practices: SAE J320a, Minimum Performance Criteria for Roll...

29 CFR 1926.1001 - Minimum performance criteria for rollover protective structures for designated scrapers, loaders...

Code of Federal Regulations, 2012 CFR

2012-07-01

... of Steel Products (available at each Regional Office of the Occupational Safety and Health... Society of Automotive Engineers Recommended Practices: SAE J320a, Minimum Performance Criteria for Roll...

Response of macroinvertebrate communities to remediation-simulating conditions in Pennsylvania streams influenced by acid mine drainage

USGS Publications Warehouse

Ross, R.M.; Long, E.S.; Dropkin, D.S.

2008-01-01

We compared naturally alkaline streams with limestone lithology to freestone streams with and without acid mine drainage (AMD) to predict benthic macroinvertebrate community recovery from AMD in limestone-treated watersheds. Surrogate-recovered (limestone) and, in many cases, freestone systems had significantly higher macroinvertebrate densities; diversity; taxa richness; Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa; EPT/chironomid ratios; scraper/collector - gatherer ratios; herbivores; collector - filterers; and scrapers. AMD-influenced systems had significantly greater numbers of Diptera and collector - gatherers. An entire trophic level (herbivores) was 'restored' in surrogate-recovered streams, which also showed greater trophic specialization. Indicator analysis identified seven taxa (within Crustacea, Diptera, Nematoda, Trichoptera, and Ephemeroptera) as significant indicators of limestone systems and six taxa (within Ephemeroptera, Plecoptera, Tricoptera, Coleoptera, and Mollusca) as significant freestone indicators, all useful as biological indicators of recovery from AMD. ?? Springer Science+Business Media B.V. 2007.

Feeding Ecology of Two Plecopterans in Low Order Andean-Patagonian Streams

NASA Astrophysics Data System (ADS)

Albariño, Ricardo J.; Díaz Villanueva, Verónica

2006-05-01

Feeding plasticity of the Andean plecopteran Klapopteryx kuscheli and Notoperla archiplatae larvae was assessed through a field experiment using enclosures. K. kuscheli has previously been described as a shredder and N. archiplatae as a scraper. Further information on gut contents from different populations supported those results. In the experiment, larvae of both species were exposed to contrasting food items: leaf litter and periphyton. Consumption, growth and the efficiency of food conversion were measured. K. kuscheli was able to feed on periphyton, though it did not grow. N. archiplatae failed to feed on leaf litter. While K. kuscheli might be considered a facultative shredder, N. archiplatae functions as a specialist scraper. The natural distribution and seasonal abundance in two small streams showed contrasting habitat use of both species. N. archiplatae inhabited high velocity runs and riffles underneath large substrates while K. kuscheli presented a higher habitat plasticity. Implications of those results for ecosystem function are discussed.

How to deal with morning bad breath: A randomized, crossover clinical trial

PubMed Central

Oliveira-Neto, Jeronimo M.; Sato, Sandra; Pedrazzi, Vinícius

2013-01-01

Context: The absence of a protocol for the treatment of halitosis has led us to compare mouthrinses with mechanical oral hygiene procedures for treating morning breath by employing a hand-held sulfide monitor. Aims: To compare the efficacy of five modalities of treatment for controlling morning halitosis in subjects with no dental or periodontal disease. Settings and Design: This is a five-period, randomized, crossover clinical trial. Materials and Methods: Twenty volunteers were randomly assigned to the trial. Testing involved the use of a conventional tongue scraper, a tongue scraper joined to the back of a toothbrush's head, two mouthrinses (0.05% cetylpyridinium chloride and 0.12% chlorhexidine digluconate) and a soft-bristled toothbrush and fluoride toothpaste for practicing oral hygiene. Statistical Analysis Used: Data analysis was performed using SPSS version 17 for Windows and NCSS 2007 software (P < 0.05). The products and the periods were compared with each other using the Friedman's test. When significant differences (P < 0.05) were determined, the products and periods were compared in pairs by using the Wilcoxon's test and by adjusting the original significance level (0.05) for multiple comparisons by using the Bonferroni's method. Results: The toothbrush's tongue scraper was able to significantly reduce bad breath for up to 2 h. Chlorhexidine reduced bad breath only at the end of the second hour, an effect that lasted for 3 h. Conclusions: Mechanical tongue cleaning was able to immediately reduce bad breath for a short period, whereas chlorhexidine and mechanical oral hygiene reduced bad breath for longer periods, achieving the best results against morning breath. PMID:24554886

Kinematics of benthic suction feeding in Callichthyidae and Mochokidae, with functional implications for the evolution of food scraping in catfishes.

PubMed

Van Wassenbergh, Sam; Lieben, Tim; Herrel, Anthony; Huysentruyt, Frank; Geerinckx, Tom; Adriaens, Dominique; Aerts, Peter

2009-01-01

Food scraping has independently evolved twice from suction feeding in the evolution of catfishes: within neotropical Loricarioidea and paleotropical Mochokidae. To gain insight in the evolutionary transitions associated with the evolution towards scraping, we analyzed prey capture kinematics in two species of benthic suction feeders which belong to taxa that are closely related to the scraper lineages (respectively, Corydoras splendens and Synodontis multipunctatus), and compared it to prey capture in a more distantly related, generalist suction feeder (Clarias gariepinus). Simultaneous ventral and lateral view high-speed videos were recorded to quantify the movements of the lower jaw, hyoid, pectoral girdle and neurocranium. Additionally, ellipse modeling was applied to relate head shape differences to buccal expansion kinematics. Similarly to what has been observed in scrapers, rotations of the neurocranium are minimal in the benthic suction feeders, and may consequently have facilitated the evolution of a scraping feeding mechanism. The hypothesis that fish with a more laterally compressed head rely more heavily on lateral expansion of the buccal cavity to generate suction, was confirmed in our sample of catfish species. Since an important contribution of lateral expansion of the head to suction may avoid the need for a strong, ventral depression of the mouth floor during feeding, we hypothesized that this may have allowed a closer association with the substrate in the ancestors of scrapers. However, our hypothesis was not supported by an ancestral state reconstruction, which suggests that scraping probably evolved from sub-terminal mouthed ancestors with dorsoventrally flattened heads.

9 CFR 590.547 - Albumen flake process drying operations.

Code of Federal Regulations, 2010 CFR

2010-01-01

... free of flies, insects, and rodents. (b) Drying units, racks, and trucks shall be kept in a clean and sanitary condition. (c) Drying pans, trays, belts, scrapers, or curing racks, if used, shall be kept in a...

7 CFR 301.80-1 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... Mechanized cultivating equipment; and mechanized harvesting equipment. Mechanized equipment used for soil..., hay balers, corn pickers, and combines. Mechanized soil-moving equipment. Mechanized equipment used to move or transport soil, e.g., draglines, bulldozers, road scrapers, and dumptrucks. Moved (movement...

7 CFR 301.80-1 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

.... Mechanized cultivating equipment; and mechanized harvesting equipment. Mechanized equipment used for soil..., hay balers, corn pickers, and combines. Mechanized soil-moving equipment. Mechanized equipment used to move or transport soil, e.g., draglines, bulldozers, road scrapers, and dumptrucks. Moved (movement...

7 CFR 301.80-1 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

.... Mechanized cultivating equipment; and mechanized harvesting equipment. Mechanized equipment used for soil..., hay balers, corn pickers, and combines. Mechanized soil-moving equipment. Mechanized equipment used to move or transport soil, e.g., draglines, bulldozers, road scrapers, and dumptrucks. Moved (movement...

7 CFR 301.80-1 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

.... Mechanized cultivating equipment; and mechanized harvesting equipment. Mechanized equipment used for soil..., hay balers, corn pickers, and combines. Mechanized soil-moving equipment. Mechanized equipment used to move or transport soil, e.g., draglines, bulldozers, road scrapers, and dumptrucks. Moved (movement...

7 CFR 301.80-1 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

.... Mechanized cultivating equipment; and mechanized harvesting equipment. Mechanized equipment used for soil..., hay balers, corn pickers, and combines. Mechanized soil-moving equipment. Mechanized equipment used to move or transport soil, e.g., draglines, bulldozers, road scrapers, and dumptrucks. Moved (movement...

Further notes on the natural history of the South American pepper frog, Leptodactylus labyrinthicus (Spix, 1824) (Anura, Leptodactylidae).

PubMed

Silva, W R; Giaretta, A A

2008-05-01

Leptodactylus labyrinthicus tadpoles reach a large size in the nest through consumption of trophic eggs. We previously suggested that the trophic eggs are laid just after amplexus has finished, but our new data do not support this hypothesis. We also present further details on the natural history of the species with regard to breeding activity, spawning site, retreats and the ability of tadpoles in preying upon fully-growth heterospecific tadpoles. We also show that the tadpoles are mainly nocturnal and take diurnal refuges. We collected the data in Brazil in three localities within the Cerrado Biome. We examined burrows used by L. labyrinthicus males, verified if females still contained mature eggs just after released from amplexus, and tested the ability of tadpoles in preying fully-growth heterospecific tadpoles. Field observations and experiments were conducted on tadpole activity time, hiding behaviour and level of susceptibility to predation by the bird leaf-scrapers in four sheltering situations. Reproduction could start before the first rains; this may be advantageous by allowing the tadpoles to exploit eggs of other frogs. We found one floating nest built in a temporary pool. The nest of the species is normally circumscribed in an excavated basin beside the water body. Adult males were found during the day with their head-out of the entrance of underwater burrows, which were perforations through dense root mats beside calling/spawning sites. Probably, these burrows in permanently water-filled soil are actively excavated by males. Females released all their eggs during the amplexus, so trophic eggs are not produced by the currently-accepted mechanism. Fully-grown heterospecific tadpoles were not preyed upon by L. labyrinthicus tadpoles, which can prey only slow-moving newly hatched ones. Field tadpoles took shelter under mud/dead leaves during daylight and became exposed on the bottom at night. Free-ranging leaf-scrapers removed dead leaves from a pool with their beaks and preyed upon tadpoles. In the experiments, the tadpoles sheltered under gravel/leaves during daylight, but they were exposed at night. Leaf-scrapers ate all exposed tadpoles, but no tadpole of the gravel/leaves trays was consumed. Hence the nocturnal habits and use of diurnal refuges may protect the tadpoles from visual predators, such as the leaf-scrapers.

242-16H 2H EVAPORATOR POT SAMPLING FINAL REPORT

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

Krementz, D; William Cheng, W

2008-06-11

Due to the materials that are processed through 2H Evaporator, scale is constantly being deposited on the surfaces of the evaporator pot. In order to meet the requirements of the Nuclear Criticality Safety Analysis/Evaluation (NCSA/NCSE) for 2H Evaporator, inspections of the pot are performed to determine the extent of scaling. Once the volume of scale reaches a certain threshold, the pot must be chemically cleaned to remove the scale. Prior to cleaning the pot, samples of the scale are obtained to determine the concentration of uranium and plutonium and also to provide information to assist with pot cleaning. Savannah Rivermore » National Laboratory (SRNL) was requested by Liquid Waste Organization (LWO) Engineering to obtain these samples from two locations within the evaporator. Past experience has proven the difficulty of successfully obtaining solids samples from the 2H Evaporator pot. To mitigate this risk, a total of four samplers were designed and fabricated to ensure that two samples could be obtained. Samples had previously been obtained from the cone surface directly below the vertical access riser using a custom scraping tool. This tool was fabricated and deployed successfully. A second scraper was designed to obtain sample from the nearby vertical thermowell and a third scraper was designed to obtain sample from the vertical pot wall. The newly developed scrapers both employed a pneumatically actuated elbow. The scrapers were designed to be easily attached/removed from the elbow assembly. These tools were fabricated and deployed successfully. A fourth tool was designed to obtain sample from the opposite side of the pot under the tube bundle. This tool was fabricated and tested, but the additional modifications required to make the tool field-ready could not be complete in time to meet the aggressive deployment schedule. Two samples were obtained near the pot entry location, one from the pot wall and the other from the evaporator feed pipe. Since a third sampler was available and all of the radiological controls were in place, the decision was made to obtain a third sample. The third sampler dropped directly below the riser to obtain a scrape sample from the evaporator cone. Samples were obtained from all of these locations in sufficient quantities to perform the required analysis.« less

Evaluation of graft cell viability-efficacy of piezoelectric versus manual bone scraper technique.

PubMed

Pekovits, Karin; Wildburger, Angelika; Payer, Michael; Hutter, Heinz; Jakse, Norbert; Dohr, Gottfried

2012-01-01

The aim of the present study was to compare the influence of 2 different bone scrapers with respect to graft quality. The study was conducted as a prospective, controlled experimental study of patients selected from the outpatient unit of the Department of Oral Surgery and Radiology (Dental Clinic, Medical University, Graz, Austria). Bone samples were obtained during routine lower third molar removal. Both a manual bone scraper (MS) and a piezoelectric device (PD) were used in directly adjacent regions in each case. As variables, the chip morphology, cell viability, and osteogenic differentiation were investigated. For statistical analysis, the Student t test and Fisher's exact test (P < .05) were applied. A total of 20 patients (12 women and 8 men, mean age 28.15 ± 5.8 years) were included in the study. A series of 40 bone samples was obtained during lower third molar removal. MS and PD enabled similar intraoral harvest of bone chips. In vitro outgrowth of adherent cells was found in 90% of the MS and 80% of the PD samples after 7 to 18 days, without statistical significance (P = .67). Similar cell viability of outgrowing cells in both groups was observed (94.7% ± 2.2% in the MS group and 94.1% ± 1.6% in the PD group). Reverse transcriptase-polymerase chain reaction analysis and the staining pattern verified osteopotent cells in both groups. Both manual and piezoelectric techniques are adequate harvesting technologies for limited intraoral augmentations. Our results did not show an advantage for the piezoelectric device. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Evaluation of Two Surface Sampling Methods for Microbiological and Chemical Analyses To Assess the Presence of Biofilms in Food Companies.

PubMed

Maes, Sharon; Huu, Son Nguyen; Heyndrickx, Marc; Weyenberg, Stephanie van; Steenackers, Hans; Verplaetse, Alex; Vackier, Thijs; Sampers, Imca; Raes, Katleen; Reu, Koen De

2017-12-01

Biofilms are an important source of contamination in food companies, yet the composition of biofilms in practice is still mostly unknown. The chemical and microbiological characterization of surface samples taken after cleaning and disinfection is very important to distinguish free-living bacteria from the attached bacteria in biofilms. In this study, sampling methods that are potentially useful for both chemical and microbiological analyses of surface samples were evaluated. In the manufacturing facilities of eight Belgian food companies, surfaces were sampled after cleaning and disinfection using two sampling methods: the scraper-flocked swab method and the sponge stick method. Microbiological and chemical analyses were performed on these samples to evaluate the suitability of the sampling methods for the quantification of extracellular polymeric substance components and microorganisms originating from biofilms in these facilities. The scraper-flocked swab method was most suitable for chemical analyses of the samples because the material in these swabs did not interfere with determination of the chemical components. For microbiological enumerations, the sponge stick method was slightly but not significantly more effective than the scraper-flocked swab method. In all but one of the facilities, at least 20% of the sampled surfaces had more than 10 2 CFU/100 cm 2 . Proteins were found in 20% of the chemically analyzed surface samples, and carbohydrates and uronic acids were found in 15 and 8% of the samples, respectively. When chemical and microbiological results were combined, 17% of the sampled surfaces were contaminated with both microorganisms and at least one of the analyzed chemical components; thus, these surfaces were characterized as carrying biofilm. Overall, microbiological contamination in the food industry is highly variable by food sector and even within a facility at various sampling points and sampling times.

77 FR 43799 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List the Gila...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-26

... scrapers feeding on a variety of water particles and algae, as well as some large plants and animal... individuals frequently feed on algae (Edmunds and Waltz 1996, p. 126). Adult mayflies have nonfunctioning...

EMISSION MEASUREMENTS OF PARTICLE MASS AND SIZE EMISSION PROFILES FROM CONSTRUCTION ACTIVITIES

EPA Science Inventory

The report gives results from field tests that characterize the amount and size distribution of particulate matter (PM) emissions from operations at construction sites. Of particular interest is the movement of earth by scraper loading and unloading, grading, transit vehicular m...

An evaluation of the efficiency of cleaning methods in a bacon factory

PubMed Central

Dempster, J. F.

1971-01-01

The germicidal efficiencies of hot water (140-150° F.) under pressure (method 1), hot water + 2% (w/v) detergent solution (method 2) and hot water + detergent + 200 p.p.m. solution of available chlorine (method 3) were compared at six sites in a bacon factory. Results indicated that sites 1 and 2 (tiled walls) were satisfactorily cleaned by each method. It was therefore considered more economical to clean such surfaces routinely by method 1. However, this method was much less efficient (31% survival of micro-organisms) on site 3 (wooden surface) than methods 2 (7% survival) and 3 (1% survival). Likewise the remaining sites (dehairing machine, black scraper and table) were least efficiently cleaned by method 1. The most satisfactory results were obtained when these surfaces were treated by method 3. Pig carcasses were shown to be contaminated by an improperly cleaned black scraper. Repeated cleaning and sterilizing (method 3) of this equipment reduced the contamination on carcasses from about 70% to less than 10%. PMID:5291745

29 CFR 1926.602 - Material handling equipment.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Brake systems for self-propelled rubber-tired off-highway equipment manufactured after January 1, 1972... Engineers Recommended Practices: Self-Propelled Scrapers SAE J319b-1971. Self-Propelled Graders SAE J236... condition. (ii) No employer shall permit earthmoving or compacting equipment which has an obstructed view to...

29 CFR 1926.602 - Material handling equipment.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Brake systems for self-propelled rubber-tired off-highway equipment manufactured after January 1, 1972... Engineers Recommended Practices: Self-Propelled Scrapers SAE J319b-1971. Self-Propelled Graders SAE J236... condition. (ii) No employer shall permit earthmoving or compacting equipment which has an obstructed view to...

29 CFR 1926.602 - Material handling equipment.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... Brake systems for self-propelled rubber-tired off-highway equipment manufactured after January 1, 1972... Engineers Recommended Practices: Self-Propelled Scrapers SAE J319b-1971. Self-Propelled Graders SAE J236... condition. (ii) No employer shall permit earthmoving or compacting equipment which has an obstructed view to...

78 FR 45964 - Notice of Intent To Repatriate Cultural Items: Monterey Museum of Art, Monterey, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-30

..., 193 cultural items of ivory, bone, wood, and stone were removed from the Iyatet site, in Nome County... scraper, 3 dogsled runners, 1 club, 4 needles or awls, and 54 other objects made of ivory, bone, wood and...

An Archeological Survey in the Gypsum Breaks on the Elm Fork of the Red River,

DTIC Science & Technology

1979-01-01

Tamarix gallica salt cedar Salix nigra black willow Opuntia lindenheimeri prickly pear cactus* Artemisia filifolia sand sage Bouteloua gracilis blue...125 projectile points were recovered including Gary, Bonham, Hayes barbed, Alba barbed, knives, drills, scrapers, gouges, cores, grinding stones

Archaeological Investigations at Site 45-DO-273, Chief Joseph Dam Project, Washington.

DTIC Science & Technology

1984-01-01

CHOPPERS . .. ........................... 60 DRILLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 GRAVERS...6 Plate 3-1. Shaft abrader, hammerstones, netslnker, and chopper . . . . 50 Plate 3-2. Blfaces and scrapers .. .. .. .... ... .... . ... 58 Plate 3...sites as low as possible. * . The Project’s Investigations are documented In four report series. Reports describing archaeological reconnaissance and

An automated scraper system for swine confinement facilities

USDA-ARS?s Scientific Manuscript database

Odor and air emissions released by some commercial, large swine operations can be a nuisance. Research has shown that some swine confinement buildings can emit significant amounts of odors, hydrogen sulfide (H2S) and other gases, especially from deep pit buildings with long-term manure storage. A m...

49 CFR 195.436 - Security of facilities.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Security of facilities. 195.436 Section 195.436... PIPELINE Operation and Maintenance § 195.436 Security of facilities. Each operator shall provide protection for each pumping station and breakout tank area and other exposed facility (such as scraper traps...

Cultural Resources Collection Analysis Albeni Falls Project, Northern Idaho.

DTIC Science & Technology

1987-01-01

numerous pestles and mortars, bolas stones, nephrite adzes, notched pebbles or net weights, an atlatl weight, and several unique incised and carved...tools including flaked and ground stone was documented; bifacial tools, drills, gravers, scrapers, numerous pestles and mortars, bolas stones, nephrite...59 27 Pestles ............................................................ 60 28 Zoomorphic pestle (?) fragment

Winter Safety Tips for Older Adults

MedlinePlus

... smaller roads. • Stock your car with basic emergency supplies such as: – First aid kid – Blankets – Extra warm clothes – Booster cables – Windshield scraper – Shovel – Rock salt or a bag of sand or cat litter (in case your wheels get stuck) – Water and dried food or canned food (with can ...

Archaeological Evaluation of Proposed Dredge Disposal Site, Lock and Dam Number 20, Adams County, Illinois.

DTIC Science & Technology

1987-03-01

7 by William Green and J. Joseph Alford ARCHAEOLOGICAL AND HISTORICAL CONTEXT ................................................... 9 by...14 7 . Test trenching with paddlewbeel scraper ............................................................. 18 8. Feature...line); archaeological site boundaries (dotted lines) Numbers ore piece plot locations See figure 10 for Piece plots in enclosed ores 7 The field then

77 FR 77037 - Procurement List; Additions

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-31

...-Compatible, 2'' x 8'' NSN: 7920-00-NIB-0545--Scrub Brush, Wire, Knuckle Guard, Long Handle, Ergonomic, 6'' x 1 1/8'', w/built-in scraper NSN: 7920-00-NIB-0547--Scrub Brush, Wire, Stainless, Ergonomic, 5'' NSN: 7920-00-NIB-0558--Scrub Brush, Wire, Black Tempered, Ergonomic, 5'' NSN: 7920-00-NIB-0563--Wire Brush...

Structural biomechanics determine spectral purity of bush-cricket calls.

PubMed

Chivers, Benedict D; Jonsson, Thorin; Soulsbury, Carl D; Montealegre-Z, Fernando

2017-11-01

Bush-crickets (Orthoptera: Tettigoniidae) generate sound using tegminal stridulation. Signalling effectiveness is affected by the widely varying acoustic parameters of temporal pattern, frequency and spectral purity (tonality). During stridulation, frequency multiplication occurs as a scraper on one wing scrapes across a file of sclerotized teeth on the other. The frequency with which these tooth-scraper interactions occur, along with radiating wing cell resonant properties, dictates both frequency and tonality in the call. Bush-cricket species produce calls ranging from resonant, tonal calls through to non-resonant, broadband signals. The differences are believed to result from differences in file tooth arrangement and wing radiators, but a systematic test of the structural causes of broadband or tonal calls is lacking. Using phylogenetically controlled structural equation models, we show that parameters of file tooth density and file length are the best-fitting predictors of tonality across 40 bush-cricket species. Features of file morphology constrain the production of spectrally pure signals, but systematic distribution of teeth alone does not explain pure-tone sound production in this family. © 2017 The Authors.

Structural biomechanics determine spectral purity of bush-cricket calls

PubMed Central

2017-01-01

Bush-crickets (Orthoptera: Tettigoniidae) generate sound using tegminal stridulation. Signalling effectiveness is affected by the widely varying acoustic parameters of temporal pattern, frequency and spectral purity (tonality). During stridulation, frequency multiplication occurs as a scraper on one wing scrapes across a file of sclerotized teeth on the other. The frequency with which these tooth–scraper interactions occur, along with radiating wing cell resonant properties, dictates both frequency and tonality in the call. Bush-cricket species produce calls ranging from resonant, tonal calls through to non-resonant, broadband signals. The differences are believed to result from differences in file tooth arrangement and wing radiators, but a systematic test of the structural causes of broadband or tonal calls is lacking. Using phylogenetically controlled structural equation models, we show that parameters of file tooth density and file length are the best-fitting predictors of tonality across 40 bush-cricket species. Features of file morphology constrain the production of spectrally pure signals, but systematic distribution of teeth alone does not explain pure-tone sound production in this family. PMID:29187608

Studies on questions of design and construction of chain scraper conveyors. [mining operations

NASA Technical Reports Server (NTRS)

Guder, H.

1980-01-01

The basic behavior of mining crushed goods in chain scraper conveyors was examined using a special test stand. The characteristics resistance lines of the upper end-piece were determined for conveyor idle as a function of the determinative crushed good characteristics (granular structure, moisture content, type of goods) on the size of the conveyor load, on the conveyor construction and on the stopped time of the conveyor. Crushed goods with a narrow granular profile and sphere-like grains caused about 35% greater resistance than fine coal and raw coal with broad granular profile. For goods containing water more than 10% by weight, the solids friction retreated in favor of flow friction. The coefficient of resistance decreased considerably in the range of lower speeds and then increased with increasing conveyor speed. The conveyance of sandstone ore required about 280% greater specific drive than the conveyance of raw coal. Resistance coefficients for coal and raw coal showed no dependence on the design of the conveyor. Start-up of loaded conveyors after longer stop times was simulated and the specific break-loose force was determined.

Natural bounds on herbivorous coral reef fishes

PubMed Central

Hoey, Andrew S.; Williams, Gareth J.; Williams, Ivor D.

2016-01-01

Humans are an increasingly dominant driver of Earth's biological communities, but differentiating human impacts from natural drivers of ecosystem state is crucial. Herbivorous fish play a key role in maintaining coral dominance on coral reefs, and are widely affected by human activities, principally fishing. We assess the relative importance of human and biophysical (habitat and oceanographic) drivers on the biomass of five herbivorous functional groups among 33 islands in the central and western Pacific Ocean. Human impacts were clear for some, but not all, herbivore groups. Biomass of browsers, large excavators, and of all herbivores combined declined rapidly with increasing human population density, whereas grazers, scrapers, and detritivores displayed no relationship. Sea-surface temperature had significant but opposing effects on the biomass of detritivores (positive) and browsers (negative). Similarly, the biomass of scrapers, grazers, and detritivores correlated with habitat structural complexity; however, relationships were group specific. Finally, the biomass of browsers and large excavators was related to island geomorphology, both peaking on low-lying islands and atolls. The substantial variability in herbivore populations explained by natural biophysical drivers highlights the need for locally appropriate management targets on coral reefs. PMID:27881745

75 FR 58424 - Notice of Intent to Repatriate Cultural Items: Northwest Museum of Arts & Culture, Spokane, WA

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-24

... bone awl pendant, 27 dentalia beads, 4 copper pendants, 1 copper bracelet, 1 projectile point and 1 bone awl. During the period July 1939 - September 1940, funerary objects were systematically removed... abalone shell pendant, 2 scrapers, 2 bone awls, 1 piece of matting, 1 flake, 2 dentalia necklace fragments...

77 FR 64326 - Procurement List; Proposed Additions and Deletions

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-19

...-Compatible, 2'' x 8''. NSN: 7920-00-NIB-0545--Scrub Brush, Wire, Knuckle Guard, Long Handle, Ergonomic, 6'' x 1 1/8'', w/built-in scraper. NSN: 7920-00-NIB-0547--Scrub Brush, Wire, Stainless, Ergonomic, 5''. NSN: 7920-00-NIB-0558--Scrub Brush, Wire, Black Tempered, Ergonomic, 5''. NSN: 7920-00-NIB-0563--Wire...

77 FR 25742 - Notice of Inventory Completion: Northwest Museum of Arts & Culture, Spokane, WA; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-01

... funerary objects are 1 basalt piece, 1 bone awl, 2 unworked and worked cache forms, 1 scraper, 2 pestles, 1..., 1 bone harpoon, 1 bone awl, 4 knives, 6 projectile points, 1 string of copper bone beads, 100... bear penis bones, 2 gravers, 13 perforated elk teeth, 2 abalone gorgets, 6 copper pendants, 5 worked...

28. HULETT NO. 4 SEEN FROM THE DECK OF THE ...

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

28. HULETT NO. 4 SEEN FROM THE DECK OF THE 'GEORGE M. CARL.' THE END OF UNLOADING, TRACTOR SCRAPERS ARE LOWERED INTO THE HOLD TO 'CLEAN UP.' PRIOR TO ABOUT 1953, MEN WITH SHOVELS DID THE JOB. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

Environmental Assessment: Anti-Terrorism/Force Protection McConnell Air Force Base, Kansas

DTIC Science & Technology

2003-09-01

handled, stored, transported, disposed, or recycled in accordance with these regulations. The potential for hazardous waste generation from gate...Loader (rubber tire) Concrete Truck Concrete Finisher Crane Asphalt Spreader Roller Flat Bed Truck (18 wheel) Scraper Trenching Machine 1...plastics, and lumber. These materials would be placed in the appropriate construction materials landfill or recycled when possible. These wastes

Effects of a crude oil spill on the benthic invertebrate community in the Gasconade River, Missouri

USGS Publications Warehouse

Poulton, Barry C.; Finger, Susan E.; Humphrey, S.A.

1997-01-01

Effects of a 3.3-million–L crude oil spill on the benthic macroinvertebrate community of the Gasconade River, a large river in Missouri, were evaluated by comparing several macroinvertebrate community indices in riffle and backwater habitats above and below the spill. Concentrations of total petroleum hydrocarbons (TPH) in sediments decreased dramatically in riffle habitats within 6 months of the spill, but elevated hydrocarbon levels (TPH = 80–270 μg/g) were still present in backwater habitats at the end of the study. Correspondingly, riffle macroinvertebrate communities recovered rapidly, but overall benthic diversity continued to be reduced in backwater areas until the end of the study 18 months after the spill. In addition, statistical analysis of benthic functional feeding groups revealed that both scrapers and shredders were reduced in backwater habitats below the oil spill. Decreased abundance of shredders and scrapers in these habitats is likely caused by oil contamination of aquatic sediments and associated organic matter required by these groups for food and substrate. Results of this study suggest that the persistence of oil in backwater habitats has a negative effect on the benthic community in large rivers.

Natural bounds on herbivorous coral reef fishes.

PubMed

Heenan, Adel; Hoey, Andrew S; Williams, Gareth J; Williams, Ivor D

2016-11-30

Humans are an increasingly dominant driver of Earth's biological communities, but differentiating human impacts from natural drivers of ecosystem state is crucial. Herbivorous fish play a key role in maintaining coral dominance on coral reefs, and are widely affected by human activities, principally fishing. We assess the relative importance of human and biophysical (habitat and oceanographic) drivers on the biomass of five herbivorous functional groups among 33 islands in the central and western Pacific Ocean. Human impacts were clear for some, but not all, herbivore groups. Biomass of browsers, large excavators, and of all herbivores combined declined rapidly with increasing human population density, whereas grazers, scrapers, and detritivores displayed no relationship. Sea-surface temperature had significant but opposing effects on the biomass of detritivores (positive) and browsers (negative). Similarly, the biomass of scrapers, grazers, and detritivores correlated with habitat structural complexity; however, relationships were group specific. Finally, the biomass of browsers and large excavators was related to island geomorphology, both peaking on low-lying islands and atolls. The substantial variability in herbivore populations explained by natural biophysical drivers highlights the need for locally appropriate management targets on coral reefs. © 2016 The Authors.

Making Do with What We Have: Use Your Bootstraps

ERIC Educational Resources Information Center

Calmettes, Guillaume; Drummond, Gordon B.; Vowler, Sarah L.

2012-01-01

A jack knife is a pocket knife that is put to many tasks, because it's ready to hand. Often there could be a better tool for the job, such as a screwdriver, a scraper, or a can-opener, but these are not usually pocket items. In statistical terms, the expression implies making do with what's available. Another simile, of an extreme situation, is…

USSR Report, International Affairs

DTIC Science & Technology

1987-02-11

shown that the cycle "A New Development—Assimilation in Production " has accelerated to practically twice its original speed thanks to these forms of... new production capacities to manufacture hydrodynamic transmissions for scrapers and loaders, and in doing so, will be assisted by a partner—the...creation of new forms of production through joint efforts. Of primary importance in achieving these new forms are mobile and flexible contacts that are in

Archaeological Investigations at the San Gabriel Reservoir Districts, Central Texas. Volume 4.

DTIC Science & Technology

1982-06-01

TEXAS Period Phase/Years B.P. Index Markers ’I. ____ Neoarchaic Toyah Perdiz, Cliffton arrow points, plano- 200 - 650 convex end scrapers, four -bevel...presented in an abbreviated format rather than in narrative form. They are segregated into four major groupings based on general characteristics; these...appear to be formally arranged are included within this category. In outline, these clusters of rocks vary from circular to irregular; four appear to

Photodynamic therapy as a novel treatment for halitosis in adolescents: study protocol for a randomized controlled trial.

PubMed

Lopes, Rubia Garcia; de Godoy, Camila Haddad Leal; Deana, Alessandro Melo; de Santi, Maria Eugenia Simões Onofre; Prates, Renato Araujo; França, Cristiane Miranda; Fernandes, Kristianne Porta Santos; Mesquita-Ferrari, Raquel Agnelli; Bussadori, Sandra Kalil

2014-11-14

Halitosis is a common problem that affects a large portion of the population worldwide. The origin of this condition is oral in 90% and systemic in 10% of cases. The unpleasant odor is mainly the result of volatile sulfur compounds produced by Gram-negative bacteria. However, it has recently been found that anaerobic Gram-positive bacteria also produce hydrogen sulfide (H2S) in the presence of amino acids, such as cysteine. Light, both with and without the use of chemical agents, has been used to induce therapeutic and antimicrobial effects. In photodynamic therapy, the antimicrobial effect is confined to areas covered by photosensitizing dye. The aim of the present study is to evaluate the antimicrobial effect of photodynamic therapy on halitosis in adolescents through the analysis of volatile sulfur compounds measured using gas chromatography and microbiological analysis of coated tongue. A quantitative clinical trial will be carried out involving 60 adolescents randomly divided into the following groups: group 1 will receive treatment with a tongue scraper, group 2 will receive photodynamic therapy applied to the posterior two-thirds of the dorsum of the tongue, and group 3 will receive combined treatment (tongue scraper and photodynamic therapy). Gas chromatography (OralChromaTM) and microbiological analysis will be used for the diagnosis of halitosis at the beginning of the study. Post-treatment evaluations will be conducted at one hour and 24 hours after treatment. The statistical analysis will include the Shapiro-Wilk test for the determination of the distribution of the data. If normal distribution is demonstrated, analysis of variance followed by Tukey's test will be used to compare groups. The Kruskal-Wallis test followed by the Student-Newman-Keuls test will be used for data with non-normal distribution. Either the paired t-test or the Wilcoxon test will be used to compare data before and after treatment, depending on the distribution of the data. The results of this trial will determine the efficacy of using photodynamic therapy alone or in combination with a tongue scraper to treat bad breath in adolescents. The protocol for this study was registered with Clinical Trials (registration number NCT02007993) on 10 December 2013.

ICAM (Integrated Computer-Aided Manufacturing) Manufacturing Cost/Design Guide. Volume 7. Technology Transfer Summary.

DTIC Science & Technology

1984-09-01

Application Cited Deere and Company e Assist in design of electronic systems for tractors, crawlers, graders, scrapers, etc. Defense Contract Audit Agency . Aid...in developing and enhancing operational audits . DoD, Cameron Station e Conduct affordability analyses; evalu- ate new start systems. DoD, Defense...document productivity gains. e Promotes better inLustry and customer re~latons by providing a common baseline or starting polut for cost vs. perfor- vanz

Description and Evaluation of the Cultural Resources within Mathews Canyon and Pine Canyon, Lincoln County, Nevada. Cultural Resources Report. Appendix,

DTIC Science & Technology

1977-09-30

U cm. (Fire cracked rock, charcoal). 28. Burials 29. Artifacts White chert scraper, obsidian biface; broken tool blanks. Flakes: obsidian , core...mostly obsidian ; 1 red chert. 30. Remarks Deer tracks & trail; horse manure; rabbit. 31. Published references 32. Accession No. __________33. Sketch map...Burials 29. Artifacts Dozens of flakes: chert, obsidian , chalcedony, basalt chert is various colors; obsidian core, red chert biface obsidian drill

Effects of hydrologic connectivity on aquatic macroinvertebrate assemblages in different marsh types

USGS Publications Warehouse

Kang, Sung-Ryong; King, Sammy L.

2013-01-01

Hydrologic connectivity can be an important driver of aquatic macroinvertebrate assemblages. Its effects on aquatic macroinvertebrate assemblages in coastal marshes, however, are relatively poorly studied. We evaluated the effects of lateral hydrologic connectivity (permanently connected ponds: PCPs; temporary connected ponds: TCPs), and other environmental variables on aquatic macroinvertebrate assemblages and functional feeding groups (FFGs) in freshwater, brackish, and saline marshes in Louisiana, USA. We hypothesized that (1) aquatic macroinvertebrate assemblages in PCPs would have higher assemblage metric values (density, biomass, Shannon-Wiener diversity) than TCPs and (2) the density and proportional abundance of certain FFGs (i.e. scrapers, shredders, and collectors) would be greater in freshwater marsh than brackish and saline marshes. The data in our study only partially supported our first hypothesis: while freshwater marsh PCPs had higher density and biomass than TCPs, assemblage metric values in saline TCPs were greater than saline PCPs. In freshwater TCPs, long duration of isolation limited access of macroinvertebrates from adjacent water bodies, which may have reduced assemblage metric values. However, the relatively short duration of isolation in saline TCPs provided more stable or similar habitat conditions, facilitating higher assemblage metric values. As predicted by our second hypothesis, freshwater PCPs and TCPs supported a greater density of scrapers, shredders, and collectors than brackish and saline ponds. Aquatic macroinvertebrate assemblages seem to be structured by individual taxa responses to salinity as well as pond habitat attributes.

The Northern Cheyenne Exodus: A Reappraisal of the Army’s Response

DTIC Science & Technology

2015-06-12

his band into the Bighorn Mountains. They eventually surrendered at Camp Robinson, Nebraska in April 1877. Little Wolf , like Dull Knife, was a Dog ...Soldier. He later left the Dog Soldiers and became head chief of the Elk Horn Scrapers. Little Wolf , also known as Two Tails, was born around 1830...Dull Knife and Little Wolf grew up in a culture that placed great value on bravery and being a warrior. That is why they became Dog Soldiers and Elk

Universal fuel basket for use with an improved oxide reduction vessel and electrorefiner vessel

DOEpatents

Herrmann, Steven D.; Mariani, Robert D.

2002-01-01

A basket, for use in the reduction of UO.sub.2 to uranium metal and in the electrorefining of uranium metal, having a continuous annulus between inner and outer perforated cylindrical walls, with a screen adjacent to each wall. A substantially solid bottom and top plate enclose the continuous annulus defining a fuel bed. A plurality of scrapers are mounted adjacent to the outer wall extending longitudinally thereof, and there is a mechanism enabling the basket to be transported remotely.

Intensive Cultural Resource Inventory of Selected Recreation Areas in the West Portion of Lake Sakakawea, Dunn, McKenzie, Mountrail and Williams Counties, North Dakota. Volume 1.

DTIC Science & Technology

1983-01-01

populations in the Northwestern Plains. Distinctive lanceolate points such as Clovis, Folsom, and Plano were used along with scrapers, choppers, and...adjacent vicinity; fluted points tend to be concentrated in the west, while Plano points have been found throughout the state. To date, no Clovis or...Indian tradition to the Archaic tradition began with Folsom. During the Plano phase many adaptations are not sig- nificantly different from Plains

Environmental and Water Quality Operational Studies. Prey Selection and Feeding Patterns of Fish in a Southern United States Hydropower Tailwater.

DTIC Science & Technology

1985-10-01

fishes in the tailwater in relation to hydropower generation were apparent. The stomach contents of fishes in the holding tank (representing...tailwater or they may be flushed out of the tailwater. 26. Consumption of tailwater biota by fish appears to be related to daily flow regimes associated...macroinvertebrates ingested by the four species of fish investigated in this study were predomi- nantly larval stages of periphyton scrapers. Growth of tailwater

The Beaverdam Group: Archaeological Investigations at 9EB92, 9EB207, 9EB208 and 9EB219 Richard B. Russell Multiple Resource Area, Elbert County, Georgia.

DTIC Science & Technology

1984-01-01

soapstone (steatite) for both vessels and 0 cooking stones, basin mortars, phyllite and slate knives, round or stemmed scrapers, three-quarter or full...gneissic rock, and soapstone . During sub- sequent review, it was pointed out that the use of quartzite for tool manufacture is without precedent in the...fashioned from non-local materials. Quartz, meta-igneous rock and soapstone could be found within 10 km of the Beaverdain Group, whereas other lithic

Thermal-hydraulics modeling for prototype testing of the W7-X high heat flux scraper element

DOE PAGES

Clark, Emily; Lumsdaine, Arnold; Boscary, Jean; ...

2017-07-28

The long-pulse operation of the Wendelstein 7-X (W7-X) stellarator experiment is scheduled to begin in 2020. This operational phase will be equipped with water-cooled plasma facing components to allow for longer pulse durations. Certain simulated plasma scenarios have been shown to produce heat fluxes that surpass the technological limits on the edges of the divertor target elements during steady-state operation. In order to reduce the heat load on the target elements, the addition of a “scraper element” (SE) is under investigation. The SE is composed of 24 water-cooled carbon fiber reinforced carbon composite monoblock units. Multiple full-scale prototypes have beenmore » tested in the GLADIS high heat flux test facility. Previous computational studies revealed discrepancies between the simulations and experimental measurements. In this work, single-phase thermal-hydraulics modeling was performed in ANSYS CFX to identify potential causes for such discrepancies. Possible explanations investigated were the effects of a non-uniform thermal contact resistance and a potential misalignment of the monoblock fibers. And while the difference between the experimental and computational results was not resolved by a non-uniform thermal contact resistance, the computational results provided insight into the potential performance of a W7-X monoblock unit. Circumferential temperature distributions highlighted the expected boiling regions of such a unit. Finally, simulations revealed that modest angles of fiber misalignment in the monoblocks result in asymmetries at the unit edges and provide temperature differences similar to the experimental results.« less

Thermal-hydraulics modeling for prototype testing of the W7-X high heat flux scraper element

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

Clark, Emily; Lumsdaine, Arnold; Boscary, Jean

The long-pulse operation of the Wendelstein 7-X (W7-X) stellarator experiment is scheduled to begin in 2020. This operational phase will be equipped with water-cooled plasma facing components to allow for longer pulse durations. Certain simulated plasma scenarios have been shown to produce heat fluxes that surpass the technological limits on the edges of the divertor target elements during steady-state operation. In order to reduce the heat load on the target elements, the addition of a “scraper element” (SE) is under investigation. The SE is composed of 24 water-cooled carbon fiber reinforced carbon composite monoblock units. Multiple full-scale prototypes have beenmore » tested in the GLADIS high heat flux test facility. Previous computational studies revealed discrepancies between the simulations and experimental measurements. In this work, single-phase thermal-hydraulics modeling was performed in ANSYS CFX to identify potential causes for such discrepancies. Possible explanations investigated were the effects of a non-uniform thermal contact resistance and a potential misalignment of the monoblock fibers. And while the difference between the experimental and computational results was not resolved by a non-uniform thermal contact resistance, the computational results provided insight into the potential performance of a W7-X monoblock unit. Circumferential temperature distributions highlighted the expected boiling regions of such a unit. Finally, simulations revealed that modest angles of fiber misalignment in the monoblocks result in asymmetries at the unit edges and provide temperature differences similar to the experimental results.« less

Experimental studies of a continuous-wave HF(DF) confocal unstable resonator. Interim report

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

Chodzko, R.A.; Cross, E.F.; Durran, D.A.

1976-05-03

A series of experiments were performed on a continuous-wave HF(DF) multiline edge-coupled confocal unstable resonator at The Aerospace Corporation MESA facility. Experimental techniques were developed to measure remotely (from a blockhouse) the output power, the near-field intensity distribution, the spatially resolved spectral content of the near field, and the far-field power distribution. A new technique in which a variable aperture calorimeter absorbing scraper (VACAS) was used for measuring the continuous-wave output power from an unstable resonator with variable-mode geometry and without the use of an output coupling mirror was developed. (GRA)

The short-term treatment effects on the microbiota at the dorsum of the tongue in intra-oral halitosis patients--a randomized clinical trial.

PubMed

Ademovski, Seida Erovic; Persson, G Rutger; Winkel, Edwin; Tangerman, Albert; Lingström, Peter; Renvert, Stefan

2013-03-01

This study aims to assess the effects of rinsing with zinc- and chlorhexidine-containing mouth rinse with or without adjunct tongue scraping on volatile sulfur compounds (VSCs) in breath air, and the microbiota at the dorsum of the tongue. A randomized single-masked controlled clinical trial with a cross-over study design over 14 days including 21 subjects was performed. Bacterial samples from the dorsum of the tongue were assayed by checkerboard DNA-DNA hybridization. No halitosis (identified by VSC assessments) at day 14 was identified in 12/21 subjects with active rinse alone, in 10/21 with adjunct use of tongue scraper, in 1/21 for negative control rinse alone, and in 3/21 in the control and tongue scraping sequence. At day 14, significantly lower counts were identified only in the active rinse sequence (p < 0.001) for 15/78 species including, Fusobacterium sp., Porphyromonas gingivalis, Pseudomonas aeruginosa, Staphylococcus aureus, and Tannerella forsythia. A decrease in bacteria from baseline to day 14 was found in successfully treated subjects for 9/74 species including: P. gingivalis, Prevotella melaninogenica, S. aureus, and Treponema denticola. Baseline VSC scores were correlated with several bacterial species. The use of a tongue scraper combined with active rinse did not change the levels of VSC compared to rinsing alone. VSC scores were not associated with bacterial counts in samples taken from the dorsum of the tongue. The active rinse alone containing zinc and chlorhexidine had effects on intra-oral halitosis and reduced bacterial counts of species associated with malodor. Tongue scraping provided no beneficial effects on the microbiota studied. Periodontally healthy subjects with intra-oral halitosis benefit from daily rinsing with zinc- and chlorhexidine-containing mouth rinse.

Cultural Resources Inventory of Lands Adjacent to Lake Winnibigoshish,

DTIC Science & Technology

1977-06-01

PC~OPicca- Poul 9i 7 11 0~f 11 I0t’l and m -La Arte rss hanki-- -iu flro oee re s~ tc-b 11Ce eLco-IOL Vsin V--j .- ],tch Lako -.. ]A C T 1 1: 1C 1) T...mprasscd 1 brk,! n lit hic art ifact, proba )lv a kinife (,-rann~ar cirlert) 5 lc?;(1 apr,2 clhert , 2 nuar*tz) F-- - ’ **: - . . ’ , , - ,-.- - --.y...recovered on shoreline survey April, 1977 yielded: Area A: beach: 1 scraper (bro:.n chalcedony) shallowis: 2 1g, Lhic, discold -r 5r(’er C., art

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

PubMed

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

2012-09-04

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.

Electrorefiner system for recovering purified metal from impure nuclear feed material

DOEpatents

Berger, John F.; Williamson, Mark A.; Wiedmeyer, Stanley G.; Willit, James L.; Barnes, Laurel A.; Blaskovitz, Robert J.

2015-10-06

An electrorefiner system according to a non-limiting embodiment of the present invention may include a vessel configured to maintain a molten salt electrolyte and configured to receive a plurality of alternately arranged cathode and anode assemblies. The anode assemblies are configured to hold an impure nuclear feed material. Upon application of the power system, the impure nuclear feed material is anodically dissolved and a purified metal is deposited on the cathode rods of the cathode assemblies. A scraper is configured to dislodge the purified metal deposited on the cathode rods. A conveyor system is disposed at a bottom of the vessel and configured to remove the dislodged purified metal from the vessel.

A mechanistic model for electricity consumption on dairy farms: definition, validation, and demonstration.

PubMed

Upton, J; Murphy, M; Shalloo, L; Groot Koerkamp, P W G; De Boer, I J M

2014-01-01

Our objective was to define and demonstrate a mechanistic model that enables dairy farmers to explore the impact of a technical or managerial innovation on electricity consumption, associated CO2 emissions, and electricity costs. We, therefore, (1) defined a model for electricity consumption on dairy farms (MECD) capable of simulating total electricity consumption along with related CO2 emissions and electricity costs on dairy farms on a monthly basis; (2) validated the MECD using empirical data of 1yr on commercial spring calving, grass-based dairy farms with 45, 88, and 195 milking cows; and (3) demonstrated the functionality of the model by applying 2 electricity tariffs to the electricity consumption data and examining the effect on total dairy farm electricity costs. The MECD was developed using a mechanistic modeling approach and required the key inputs of milk production, cow number, and details relating to the milk-cooling system, milking machine system, water-heating system, lighting systems, water pump systems, and the winter housing facilities as well as details relating to the management of the farm (e.g., season of calving). Model validation showed an overall relative prediction error (RPE) of less than 10% for total electricity consumption. More than 87% of the mean square prediction error of total electricity consumption was accounted for by random variation. The RPE values of the milk-cooling systems, water-heating systems, and milking machine systems were less than 20%. The RPE values for automatic scraper systems, lighting systems, and water pump systems varied from 18 to 113%, indicating a poor prediction for these metrics. However, automatic scrapers, lighting, and water pumps made up only 14% of total electricity consumption across all farms, reducing the overall impact of these poor predictions. Demonstration of the model showed that total farm electricity costs increased by between 29 and 38% by moving from a day and night tariff to a flat tariff. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effects of Habitat Characteristics and Water Quality on Macroinvertebrate Communities along the Neversink Riverin Southeastern New York, 1991-2001

USGS Publications Warehouse

Ernst, Anne G.; Baldigo, Barry P.; Schuler, George E.; Apse, Colin D.; Carter, James L.; Lester, Gary T.

2008-01-01

The Neversink River, in the Catskill Mountains of southeastern New York State, feeds the Neversink Reservoir, which diverts 85 percent of the river?s flow to New York City. Acidification of several headwater reaches has affected macroinvertebrate assemblages throughout the river system above the reservoir, and the alteration of flow conditions below the reservoir dam has affected macroinvertebrate assemblages for at least 10 kilometers downstream from the reservoir. In 1999, the U.S. Geological Survey, in cooperation with The Nature Conservancy, compiled data from 30 stream reaches to quantify the effects of acidification and of the reservoir on the structure and function of macroinvertebrate assemblages throughout the Neversink River. Acidic headwater reaches supported greater numbers of acid-tolerant chironomid taxa and fewer numbers of acid-sensitive Ephemeroptera and Trichoptera than neutral reaches, and fewer scraper individuals and more shredder individuals. The 14 reaches below the reservoir, with sharply decreased flows and altered flow patterns compared to reaches above the reservoir, supported more Chironomidae and fewer Ephemeroptera and Trichoptera than the upper reaches; they also had greater numbers of shredder individuals and fewer scraper and filterer individuals than reaches above the reservoir. Water-quality variables such as pH and aluminum concentration appear to have affected macroinvertebrate assemblages more strongly in the headwaters than below the reservoir, whereas physical-habitat variables such as mean channel width and water temperature have affected these assemblages more strongly downstream from the reservoir than in the headwaters. The water-quality changes due to acidification, combined with the decreased flows and lowered water temperatures below the reservoir, have disrupted downstream continuum of macroinvertebrate communities that would normally be observed from the headwaters to the mouth. The information presented herein provides a basis for further evaluation of the Neversink and similar river systems, and for assessment of the effectiveness of future conservation efforts.

Malaysia`s Peninsular Gas system gets another segment

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

Savini, C.F.

1997-12-01

Stage 3 of Malaysia`s Peninsular Gas utilization Project is nearing completion by a joint venture of Saipem (Malaysia) Sdn Bhd and Peremba Construction Sdn Bhd. Under Petronas Gas Berhad, all stages of the Peninsular Gas Utilization Project are to provide natural gas to commercial customers recovered from complexes off the east coast of the Malaysian Peninsula. Stage 3 consists of 448 km of 36-in. pipeline from the Stage 2 teeoff in Meru, Selangor, northward to Pauh in Perlis, close to the Malaysian-Thailand border. Included in the permanent facilities are six main line valve stations, two scraper stations, six cathodic-protection stations,more » and five teeoffs. The paper discusses construction, cathodic protection, hydrostatic testing, and quality assurance.« less

[Dust and gas factors in extraction of polymetallic ore in Arctic conditions and their hygienic assessment].

PubMed

Borisenkova, R V; Lutsenko, L A; Skriabin, S Iu; Khristenko, P P

1996-01-01

Studies of drilling and blasting method of copper and nickel ores extraction at underground Transpolar mines proved that the highest concentrations of dust appeared during dry drilling of vertical blast holes, work of scraper windlass, fragmentation of out-size blocks, preparation of concrete mixture. Presence of aggressive metals, especially nickel, in the ore dust is a main base for planned thorough investigations of fibrogenic, toxic and carcinogenic effects of copper and nickel ore dust, for more precise assessment of its MAC in the air of workplace. Two-step purification of exhaust gases appearing due to mining diesel machines is not quite efficient, as the concentrations of nitrogen oxides (assessed through nitrogen dioxide) continually exceeded the MAC.

A-E Services to Perform a Cathodic Protection Survey of the Bulk Fuel Terminals at N.S.C. Pearl Harbor, Hawaii. Volume I.

DTIC Science & Technology

1982-06-01

20) From VC-D to VC-E a. 8" Avgas Line - Coated Steel (21) From FC -E to Victor Dock #1 a. 12" Avgas Line - Coated Steel (22) From Air Force Scraper...14. Bldg. S776 3" Ballast Line to VC-2 - 775 3" Ballast Line to Loading Rack - 775 15. 6" Water Line, 10’ N of Bldg. S776 - 745 6" AFFF Line, N of...S776 3" Ballast line to VC-2 - 740 - 775 35 3" Ballast line to Loading Rack - 740 - 775 35 15. 6" Water line 10’ N of Bldg. S776 - 710 - 745 35 6" AFFF

Invasive alien species water hyacinth Eichhornia crassipes as abode for macroinvertebrates in hypertrophic Ramsar Site, Lake Xochimilco, Mexico.

PubMed

Rocha-Ramirez, A; Robles-Valderrama, E; Ramirez-Flores, E

2014-11-01

This paper presents information on the density, diversity and functional feeding groups of macroinvertebrate assemblages associated with water hyacinth in Antiguo Canal Cuemanco, part of Lake Xochimilco in Mexico City. Rare (low frequency and density) and dominant (high frequency and density) taxa prevailed in the assemblages, with the most predominant being Hyalella azteca, Chironomus plumosus and Ischnura denticollis. Nonmetric Multidimensional Scaling confirmed two climatic seasons: warm-rainy and cold-dry; the former with the highest diversity and density of taxa. Canonical Correspondence Analysis showed that conductivity, nitrates and turbidity explained the density variations of taxa. Antiguo Canal Cuemanco waters are spatially homogeneous with the characteristics of hypertrophic shallow lakes, inhabited by scrapers and gathering-collectors. The species found were tolerant to organic pollution.

A linked land-sea modeling framework to inform ridge-to-reef management in high oceanic islands.

PubMed

Delevaux, Jade M S; Whittier, Robert; Stamoulis, Kostantinos A; Bremer, Leah L; Jupiter, Stacy; Friedlander, Alan M; Poti, Matthew; Guannel, Greg; Kurashima, Natalie; Winter, Kawika B; Toonen, Robert; Conklin, Eric; Wiggins, Chad; Knudby, Anders; Goodell, Whitney; Burnett, Kimberly; Yee, Susan; Htun, Hla; Oleson, Kirsten L L; Wiegner, Tracy; Ticktin, Tamara

2018-01-01

Declining natural resources have led to a cultural renaissance across the Pacific that seeks to revive customary ridge-to-reef management approaches to protect freshwater and restore abundant coral reef fisheries. Effective ridge-to-reef management requires improved understanding of land-sea linkages and decision-support tools to simultaneously evaluate the effects of terrestrial and marine drivers on coral reefs, mediated by anthropogenic activities. Although a few applications have linked the effects of land cover to coral reefs, these are too coarse in resolution to inform watershed-scale management for Pacific Islands. To address this gap, we developed a novel linked land-sea modeling framework based on local data, which coupled groundwater and coral reef models at fine spatial resolution, to determine the effects of terrestrial drivers (groundwater and nutrients), mediated by human activities (land cover/use), and marine drivers (waves, geography, and habitat) on coral reefs. We applied this framework in two 'ridge-to-reef' systems (Hā'ena and Ka'ūpūlehu) subject to different natural disturbance regimes, located in the Hawaiian Archipelago. Our results indicated that coral reefs in Ka'ūpūlehu are coral-dominated with many grazers and scrapers due to low rainfall and wave power. While coral reefs in Hā'ena are dominated by crustose coralline algae with many grazers and less scrapers due to high rainfall and wave power. In general, Ka'ūpūlehu is more vulnerable to land-based nutrients and coral bleaching than Hā'ena due to high coral cover and limited dilution and mixing from low rainfall and wave power. However, the shallow and wave sheltered back-reef areas of Hā'ena, which support high coral cover and act as nursery habitat for fishes, are also vulnerable to land-based nutrients and coral bleaching. Anthropogenic sources of nutrients located upstream from these vulnerable areas are relevant locations for nutrient mitigation, such as cesspool upgrades. In this study, we located coral reefs vulnerable to land-based nutrients and linked them to priority areas to manage sources of human-derived nutrients, thereby demonstrating how this framework can inform place-based ridge-to-reef management.

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

Morgan, W.C.; Schermerhorn, J.G.

Recently passed federal strip mining legislation in the USA officially emphasizes that the increased coal production required by the United States through surface mining is going to be obtained only with stricter environmental standards. Dozing overburden down the hillside in Appalachian contour mining or leaving dragline spoils in area mining is now taboo and it is now, or will soon be, necessary to return the disturbed land to as good or better condition than before mining. These new restrictions will create a need for new and better ways to do the job. This article describes one approach for utilizing scrapersmore » and dozers to strip all of the overburden and to replace it in an environmentally satisfactory fashion. The objective was to do this at a lower cost than that possible with the traditional dragline system by using dozers and scrapers for reclamation and topsoil handling.« less

U.sup.+4 generation in HTER

DOEpatents

Miller, William E [Naperville, IL; Gay, Eddie C [Park Forest, IL; Tomczuk, Zygmunt [Homer Glen, IL

2006-03-14

A improved device and process for recycling spent nuclear fuels, in particular uranium metal, that facilitates the refinement and recovery of uranium metal from spent metallic nuclear fuels. The electrorefiner device comprises two anodes in predetermined spatial relation to a cathode. The anodese have separate current and voltage controls. A much higher voltage than normal for the electrorefining process is applied to the second anode, thereby facilitating oxidization of uranium (III), U.sup.+, to uranium (IV), U.sup.+4. The current path from the second anode to the cathode is physically shorter than the similar current path from the second anode to the spent nuclear fuel contained in a first anode shaped as a basket. The resulting U.sup.+4 oxidizes and solubilizes rough uranium deposited on the surface of the cathode. A softer uranium metal surface is left on the cathode and is more readily removed by a scraper.

Another window to the subsistence of Middle Pleistocene hominins in Europe: A taphonomic study of Cuesta de la Bajada (Teruel, Spain)

NASA Astrophysics Data System (ADS)

Domínguez-Rodrigo, Manuel; Barba, Rebeca; Soto, Enrique; Sesé, Carmen; Santonja, Manuel; Pérez-González, Alfredo; Yravedra, José; Galán, Ana Belén

2015-10-01

Cuesta de la Bajada is a Middle Pleistocene site (MIS 8-9) in which some of the earliest evidence of Middle Paleolithic stone tool tradition is documented. The small format tool assemblage, dominated by simple flakes and scrapers, is associated to abundant remains of equids and cervids, in which both percussion and cut marks are well represented. The anatomical distribution of these bone surface modifications indicate primary access to fleshed carcasses by hominins. Hunting is further supported by the analysis of age profiles, in which prime adults are predominant both in equids and cervids. The taphonomic analysis of the site adds more information to human predatory behaviors as documented in other Middle Pleistocene sites and is one of the best examples of hunting documented in the Middle Pleistocene European archaeological record.

POP bioaccumulation in macroinvertebrates of alpine freshwater systems.

PubMed

Bizzotto, E C; Villa, S; Vighi, M

2009-12-01

This study serves to investigate the uptake of POPs in the different trophic levels (scrapers, collectors, predators, shredders) of macroinvertebrate communities sampled from a glacial and a non-glacial stream in the Italian Alps. The presented results show that the contaminant concentrations in glacial communities are generally higher compared to those from non-glacial catchments, highlighting the importance of glaciers as temporary sinks of atmospherically transported pollutants. Moreover, the data also suggests that in mountain systems snow plays an important role in influencing macroinvertebrate contamination. The main chemical uptake process to the macroinvertebrates is considered to be bioconcentration from water, as similar contaminant profiles were observed between the different trophic levels. The role of biomagnification/bioaccumulation is thought to be absent or negligible. The enrichment of chemicals observed in the predators is likely to be related to their greater lipid content compared to that of other feeding groups.

A linked land-sea modeling framework to inform ridge-to-reef management in high oceanic islands

PubMed Central

Whittier, Robert; Stamoulis, Kostantinos A.; Bremer, Leah L.; Jupiter, Stacy; Friedlander, Alan M.; Poti, Matthew; Guannel, Greg; Kurashima, Natalie; Winter, Kawika B.; Toonen, Robert; Conklin, Eric; Wiggins, Chad; Knudby, Anders; Goodell, Whitney; Burnett, Kimberly; Yee, Susan; Htun, Hla; Oleson, Kirsten L. L.; Wiegner, Tracy; Ticktin, Tamara

2018-01-01

Declining natural resources have led to a cultural renaissance across the Pacific that seeks to revive customary ridge-to-reef management approaches to protect freshwater and restore abundant coral reef fisheries. Effective ridge-to-reef management requires improved understanding of land-sea linkages and decision-support tools to simultaneously evaluate the effects of terrestrial and marine drivers on coral reefs, mediated by anthropogenic activities. Although a few applications have linked the effects of land cover to coral reefs, these are too coarse in resolution to inform watershed-scale management for Pacific Islands. To address this gap, we developed a novel linked land-sea modeling framework based on local data, which coupled groundwater and coral reef models at fine spatial resolution, to determine the effects of terrestrial drivers (groundwater and nutrients), mediated by human activities (land cover/use), and marine drivers (waves, geography, and habitat) on coral reefs. We applied this framework in two ‘ridge-to-reef’ systems (Hā‘ena and Ka‘ūpūlehu) subject to different natural disturbance regimes, located in the Hawaiian Archipelago. Our results indicated that coral reefs in Ka‘ūpūlehu are coral-dominated with many grazers and scrapers due to low rainfall and wave power. While coral reefs in Hā‘ena are dominated by crustose coralline algae with many grazers and less scrapers due to high rainfall and wave power. In general, Ka‘ūpūlehu is more vulnerable to land-based nutrients and coral bleaching than Hā‘ena due to high coral cover and limited dilution and mixing from low rainfall and wave power. However, the shallow and wave sheltered back-reef areas of Hā‘ena, which support high coral cover and act as nursery habitat for fishes, are also vulnerable to land-based nutrients and coral bleaching. Anthropogenic sources of nutrients located upstream from these vulnerable areas are relevant locations for nutrient mitigation, such as cesspool upgrades. In this study, we located coral reefs vulnerable to land-based nutrients and linked them to priority areas to manage sources of human-derived nutrients, thereby demonstrating how this framework can inform place-based ridge-to-reef management. PMID:29538392

Local Geomorphology as a Determinant of Macrofaunal Production in a Mountain Stream.

PubMed

Huryn, Alexander D; Wallace, J Bruce

1987-12-01

By comparing distributions of functional group production among different habitats in an Appalachian mountain stream, the influence of site-specific geomorphology upon the overall functional group composition of the animal community was demonstrated. By replicated monthly sampling, substrate particle size distributions, current velocity, standing crops of benthic organic matter, and production of macrofauna were measured in each of three principal habitats: bedrock-outcrop, riffle, and pool. Samples were taken at randomly assigned locations and the relative number of samples taken from each habitat was assumed to be proportional to the area of the habitat within the stream. These proportions were used to weight production measured in each habitat and the resulting values were summed to obtain production per unit area of average stream bed. The bedrock-outcrop habitat was characterized by high material entertainment and export as indicated by significantly higher current velocities and lower standing crops of detritus compared to the riffle and pool habitats. Pools were sites of low entertainment and high retention of organic matter as demonstrated by significantly lower current velocities and higher accumulations of detritus than other habitats. The riffle habitat was intermediate to the bedrock-outcrop and pool habitats in all parameters measured. Annual production of collector-filterers was highest in the bedrock-outcrop (ash-free dry mass 1920 mg/m 2 ), followed by riffle (278 mg/m 2 ) and pool (32 mg/m 2 ). Although constituting only 19% of the stream area, the bedrock-outcrop habitat contributed 68% of the habitat-weighted collector-filterer production. Annual production of shredders was highest in pools (2616 mg/m 2 ), followed by riffles (1657 mg/m 2 ) and bedrock-outcrop (579 mg/m 2 ). The pool habitat, constituting 23% of stream area, contributed 36% of shredder production. Annual production of scrapers was highest in the riffle habitat (905 mg/m 2 ), followed by bedrock-outcrop (517-mg/m 2 ) and pool (238 mg/m 2 ). Riffles constituted 58% of total stream area and were the source of 77% of the habitat-weighted scraper production. Annual production of engulfing predators was greatest in the pool habitat (2313 mg/m 2 ), followed by riffles (1765 mg/m 2 ) and bedrock-outcrop (687 mg/m 2 ). The relatively lower production of engulfing predators in the bedrock-outcrop habitat reflects a functional shift in mode of resource acquisition by predators, with predaceous collector-filterers (Arcto-psychinae: Trichoptera) predominating in the bedrock-outcrop. Collector-gatherer production was more evenly distributed, with the bedrock-outcrop, riffle, and pool habitats each contributing 14, 54, and 33% to the habitat-weighted production, respectively. Unlike all other functional groups, this distribution was not significantly different from the distribution of stream area among habitats and reflected lack of dependence on specific physical attributes of the local environment for access to food by members of this functional group. Local geomorphology determined the diversity and spatial distribution of bedrock-outcrops, riffles, and pools in the study stream. In turn, the functional structure of the macrofauna, when viewed holistically, was the result of the integration of the relative contributions of each habitat type of total stream area. Total habitat-weighted annual production in the study stream was estimated at 5093 and 1921 mg/m 2 for primary and secondary consumers, respectively. The distribution of habitat-weighted production among functional groups was: collector-gatherers (39%), followed by shredders (225), engulfing predators (22%), scrapers (13%), and collector-filterers (8%). This functional structure agrees favorably with current conceptual models of head water streams draining forested catchments. © 1987 by the Ecological Society of America.

Arroyo del Vizcaíno, Uruguay: a fossil-rich 30-ka-old megafaunal locality with cut-marked bones

PubMed Central

Fariña, Richard A.; Tambusso, P. Sebastián; Varela, Luciano; Czerwonogora, Ada; Di Giacomo, Mariana; Musso, Marcos; Bracco, Roberto; Gascue, Andrés

2014-01-01

Human–megafauna interaction in the Americas has great scientific and ethical interest because of its implications on Pleistocene extinction. The Arroyo del Vizcaíno site near Sauce, Uruguay has already yielded over 1000 bones belonging to at least 27 individuals, mostly of the giant sloth Lestodon. The assemblage shows some taphonomic features suggestive of human presence, such as a mortality profile dominated by prime adults and little evidence of major fluvial transport. In addition, several bones present deep, asymmetrical, microstriated, sharp and shouldered marks similar to those produced by human stone tools. A few possible lithic elements have also been collected, one of which has the shape of a scraper and micropolish consistent with usage on dry hide. However, the radiocarbon age of the site is unexpectedly old (between 27 and 30 thousand years ago), and thus may be important for understanding the timing of the peopling of America. PMID:24258717

Observation of a variable sub-THz radiation driven by a low energy electron beam from a thermionic rf electron gun

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

Smirnov, A. V.; Agustsson, R.; Berg, W. J.

We report observations of an intense sub-THz radiation extracted from a ~3 MeV electron beam with a flat transverse profile propagating between two parallel oversized copper gratings with side openings. Low-loss radiation outcoupling is accomplished using a horn antenna and a miniature permanent magnet separating sub-THz and electron beams. A tabletop experiment utilizes a radio frequency thermionic electron gun delivering a thousand momentum-chirped microbunches per macropulse and an alpha-magnet with a movable beam scraper producing sub-mm microbunches. The radiated energy of tens of micro-Joules per radio frequency macropulse is demonstrated. The frequency of the radiation peak was generated and tunedmore » across two frequency ranges: (476–584) GHz with 7% instantaneous spectrum bandwidth, and (311–334) GHz with 38% instantaneous bandwidth. In this study, the prototype setup features a robust compact source of variable frequency, narrow bandwidth sub-THz pulses.« less

High temperature thermal energy storage, including a discussion of TES integrated into power plants

NASA Technical Reports Server (NTRS)

Turner, R. H.

1978-01-01

Storage temperatures of 260 C and above are considered. Basic considerations concerning energy thermal storage are discussed, taking into account general aspects of thermal energy storage, thermal energy storage integrated into power plants, thermal storage techniques and technical considerations, and economic considerations. A description of system concepts is provided, giving attention to a survey of proposed concepts, storage in unpressurized fluids, water storage in pressurized containers, the use of an underground lined cavern for water storage, a submerged thin insulated steel shell under the ocean containing pressurized water, gas passage through solid blocks, a rock bed with liquid heat transport fluid, hollow steel ingots, heat storage in concrete or sand, sand in a fluidized bed, sand poured over pipes, a thermal energy storage heat exchanger, pipes or spheres filled with phase change materials (PCM), macroencapsulated PCM with heat pipe concept for transport fluid, solid PCM removed from heat transfer pipes by moving scrapers, and the direct contact between PCM and transport fluid.

Initial excavation and dating of Ngalue Cave: a Middle Stone Age site along the Niassa Rift, Mozambique.

PubMed

Mercader, Julio; Asmerom, Yemane; Bennett, Tim; Raja, Mussa; Skinner, Anne

2009-07-01

Direct evidence for a systematic occupation of the African tropics during the early late Pleistocene is lacking. Here, we report a record of human occupation between 105-42ka, based on results from a radiometrically-dated cave section from the Mozambican segment of the Niassa (Malawi/Nyasa) Rift called Ngalue. The sedimentary sequence from bottom to top has five units. We concentrate on the so-called "Middle Beds," which contain a Middle Stone Age industry characterized by the use of the discoidal reduction technique. A significant typological feature is the presence of formal types such as points, scrapers, awls, and microliths. Special objects consist of grinders/core-axes covered by ochre. Ngalue is one of the few directly-dated Pleistocene sites located along the biogeographical corridor for modern human dispersals that links east, central, and southern Africa, and, with further study, may shed new light on hominin cave habitats during the late Pleistocene.

HybridICE® filter: ice separation in freeze desalination of mine waste waters.

PubMed

Adeniyi, A; Maree, J P; Mbaya, R K K; Popoola, A P I; Mtombeni, T; Zvinowanda, C M

2014-01-01

Freeze desalination is an alternative method for the treatment of mine waste waters. HybridICE(®) technology is a freeze desalination process which generates ice slurry in surface scraper heat exchangers that use R404a as the primary refrigerant. Ice separation from the slurry takes place in the HybridICE filter, a cylindrical unit with a centrally mounted filter element. Principally, the filter module achieves separation of the ice through buoyancy force in a continuous process. The HybridICE filter is a new and economical means of separating ice from the slurry and requires no washing of ice with water. The performance of the filter at a flow-rate of 25 L/min was evaluated over time and with varied evaporating temperature of the refrigerant. Behaviours of the ice fraction and residence time were also investigated. The objective was to find ways to improve the performance of the filter. Results showed that filter performance can be improved by controlling the refrigerant evaporating temperature and eliminating overflow.

Community-level response of fishes and aquatic macroinvertebrates to stream restoration in a third-order tributary of the Potomac River, USA

USGS Publications Warehouse

Selego, S.M.; Rose, C.L.; Merovich, G.T.; Welsh, S.A.; Anderson, James T.

2012-01-01

Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010). Collector filterers and scrapers replaced collector gatherers as the dominant macroinvertebrate functional feeding groups in the restoration reach. Before restoration, based on indices of biotic integrity (IBI), the restoration reach fish and macroinvertebrate communities closely resembled those sampled from the control reaches, and after restoration more closely resembled those from the reference reaches. Although the macroinvertebrate community responded more favorably than the fish community, both communities recovered quickly from the temporary impairment caused by the disturbance of restoration procedures and suggest rapid improvement in local ecological conditions. Copyright ?? 2012 Stephen M. Selego et al.

Community-level response of fishes and aquatic macroinvertebrates to stream restoration in a third-order tributary of the Potomac River, USA

USGS Publications Warehouse

Selego, Stephen M.; Rose, Charnee L.; Merovich, George T.; Welsh, Stuart A.; Anderson, James T.

2012-01-01

Natural stream channel design principles and riparian restoration practices were applied during spring 2010 to an agriculturally impaired reach of the Cacapon River, a tributary of the Potomac River which flows into the Chesapeake Bay. Aquatic macroinvertebrates and fishes were sampled from the restoration reach, two degraded control, and two natural reference reaches prior to, concurrently with, and following restoration (2009 through 2010). Collector filterers and scrapers replaced collector gatherers as the dominant macroinvertebrate functional feeding groups in the restoration reach. Before restoration, based on indices of biotic integrity (IBI), the restoration reach fish and macroinvertebrate communities closely resembled those sampled from the control reaches, and after restoration more closely resembled those from the reference reaches. Although the macroinvertebrate community responded more favorably than the fish community, both communities recovered quickly from the temporary impairment caused by the disturbance of restoration procedures and suggest rapid improvement in local ecological conditions.

Longitudinal Distribution of the Functional Feeding Groups of Aquatic Insects in Streams of the Brazilian Cerrado Savanna.

PubMed

Brasil, L S; Juen, L; Batista, J D; Pavan, M G; Cabette, H S R

2014-10-01

We demonstrate that the distribution of the functional feeding groups of aquatic insects is related to hierarchical patch dynamics. Patches are sites with unique environmental and functional characteristics that are discontinuously distributed in time and space within a lotic system. This distribution predicts that the occurrence of species will be based predominantly on their environmental requirements. We sampled three streams within the same drainage basin in the Brazilian Cerrado savanna, focusing on waterfalls and associated habitats (upstream, downstream), representing different functional zones. We collected 2,636 specimens representing six functional feeding groups (FFGs): brushers, collector-gatherers, collector-filterers, shredders, predators, and scrapers. The frequency of occurrence of these groups varied significantly among environments. This variation appeared to be related to the distinct characteristics of the different habitat patches, which led us to infer that the hierarchical patch dynamics model can best explain the distribution of functional feeding groups in minor lotic environments, such as waterfalls.

Observation of a variable sub-THz radiation driven by a low energy electron beam from a thermionic rf electron gun

DOE PAGES

Smirnov, A. V.; Agustsson, R.; Berg, W. J.; ...

2015-09-29

We report observations of an intense sub-THz radiation extracted from a ~3 MeV electron beam with a flat transverse profile propagating between two parallel oversized copper gratings with side openings. Low-loss radiation outcoupling is accomplished using a horn antenna and a miniature permanent magnet separating sub-THz and electron beams. A tabletop experiment utilizes a radio frequency thermionic electron gun delivering a thousand momentum-chirped microbunches per macropulse and an alpha-magnet with a movable beam scraper producing sub-mm microbunches. The radiated energy of tens of micro-Joules per radio frequency macropulse is demonstrated. The frequency of the radiation peak was generated and tunedmore » across two frequency ranges: (476–584) GHz with 7% instantaneous spectrum bandwidth, and (311–334) GHz with 38% instantaneous bandwidth. In this study, the prototype setup features a robust compact source of variable frequency, narrow bandwidth sub-THz pulses.« less

On Vastness and Variability: Cultural Transmission, Historicity, and the Paleoindian Record in Eastern South America.

PubMed

Araujo, Astolfo G M

2015-01-01

Eastern South America, or what is today Brazilian territory, poses interesting questions about the early human occupation of the Americas. Three totally distinct and contemporaneous lithic technologies, dated between 11,000 and 10,000 14C BP, are present in different portions of the country: the Umbu tradition in the south, with its formal bifacial industry, with well-retouched scrapers and bifacial points; the Itaparica tradition in the central-west / northwest, totally unifacial, whose only formal artifacts are limaces; and the "Lagoa Santa" industry, completely lacking any formal artifacts, composed mainly of small quartz flakes. Our data suggests that these differences are not related to subsistence or raw-material constraints, but rather to different cultural norms and transmission of strongly divergent chaînes opératoires. Such diversity in material culture, when viewed from a cultural transmission (CT) theory standpoint, seems at odds with a simple Clovis model as the origin of these three cultural traditions given the time elapsed since the first Clovis ages and the expected population structure of the early South American settlers.

Bifenthrin causes trophic cascades and alters insect emergence in mesocosms: implication for small streams

USGS Publications Warehouse

Rogers, Holly; Schmidt, Travis S.; Dabney, Brittanie L.; Hladik, Michelle; Mahler, Barbara J.; Van Metre, Peter C.

2016-01-01

Direct and indirect ecological effects of the widely used insecticide bifenthrin on stream ecosystems are largely unknown. To investigate such effects, a manipulative experiment was conducted in stream mesocosms that were colonized by aquatic insect communities and exposed to bifenthrin-contaminated sediment; implications for natural streams were interpreted through comparison of mesocosm results to a survey of 100 Midwestern streams, USA. In the mesocosm experiment, direct effects of bifenthrin exposure included reduced larval macroinvertebrate abundance, richness, and biomass at concentrations (EC50s ranged 197.6 – 233.5 ng bifenthrin/ g organic carbon) previously thought safe for aquatic life. Indirect effects included a trophic cascade in which periphyton abundance increased after macroinvertebrate scrapers decreased. Adult emergence dynamics and corresponding terrestrial subsidies were altered at all bifenthrin concentrations tested. Extrapolating these results to the Midwestern stream assessment suggests pervasive ecological effects, with altered emergence dynamics likely in 40% of streams and a trophic cascade in 7% of streams. This study provides new evidence that a common pyrethroid might alter aquatic and terrestrial ecosystem function at the regional scale.

Bifenthrin Causes Trophic Cascade and Altered Insect Emergence in Mesocosms: Implications for Small Streams.

PubMed

Rogers, Holly A; Schmidt, Travis S; Dabney, Brittanie L; Hladik, Michelle L; Mahler, Barbara J; Van Metre, Peter C

2016-11-01

Direct and indirect ecological effects of the widely used insecticide bifenthrin on stream ecosystems are largely unknown. To investigate such effects, a manipulative experiment was conducted in stream mesocosms that were colonized by aquatic insect communities and exposed to bifenthrin-contaminated sediment; implications for natural streams were interpreted through comparison of mesocosm results to a survey of 100 Midwestern streams, USA. In the mesocosm experiment, direct effects of bifenthrin exposure included reduced larval macroinvertebrate abundance, richness, and biomass at concentrations (EC 50 's ranged from 197.6 to 233.5 ng bifenthrin/g organic carbon) previously thought safe for aquatic life. Indirect effects included a trophic cascade in which periphyton abundance increased after macroinvertebrate scrapers decreased. Adult emergence dynamics and corresponding terrestrial subsidies were altered at all bifenthrin concentrations tested. Extrapolating these results to the Midwestern stream assessment suggests pervasive ecological effects, with altered emergence dynamics likely in 40% of streams and a trophic cascade in 7% of streams. This study provides new evidence that a common pyrethroid might alter aquatic and terrestrial ecosystem function at the regional scale.

Hawkmoths produce anti-bat ultrasound

PubMed Central

Barber, Jesse R.; Kawahara, Akito Y.

2013-01-01

Bats and moths have been engaged in aerial warfare for nearly 65 Myr. This arms race has produced a suite of counter-adaptations in moths, including bat-detecting ears. One set of defensive strategies involves the active production of sound; tiger moths' ultrasonic replies to bat attack have been shown to startle bats, warn the predators of bad taste and jam their biosonar. Here, we report that hawkmoths in the Choerocampina produce entirely ultrasonic sounds in response to tactile stimulation and the playback of biosonar attack sequences. Males do so by grating modified scraper scales on the outer surface of the genital valves against the inner margin of the last abdominal tergum. Preliminary data indicate that females also produce ultrasound to touch and playback of echolocation attack, but they do so with an entirely different mechanism. The anti-bat function of these sounds is unknown but might include startling, cross-family acoustic mimicry, warning of unprofitability or physical defence and/or jamming of echolocation. Hawkmoths present a novel and tractable system to study both the function and evolution of anti-bat defences. PMID:23825084

Persistence and clearance of different Salmonella serovars in buildings housing laying hens.

PubMed

Carrique-Mas, J J; Breslin, M; Snow, L; McLaren, I; Sayers, A R; Davies, R H

2009-06-01

We investigated factors associated with persistence of different Salmonella serovars in buildings housing laying hens in Great Britain using survival analysis. A total of 264 incidents of Salmonella detection occurring between July 1998 and August 2007 in 152 houses were recorded. For incidents involving Salmonella Enteritidis (SE), both the rodent score of the house and the type of house were positively associated with persistence. For non-SE serovars, only the type of house was associated with persistence. Persistence of SE in the houses was longest (>15 months) in step-cage and cage-scraper houses when high levels of rodents were present, and lowest in non-cage and cage-belt houses. We estimated that 42% (95% CI 23.3-63.1) of SE incidents may be cleared during the lay period, and this was related to elimination of rodents from the houses. From January 2009, EU legislation will ban the sale of fresh eggs from SE-positive and S. Typhimurium-positive flocks over their remaining lifespan. If infection is eliminated from such flocks, they would cease to represent a public health risk.

Impacts of urban landuse on macroinvertebrate communities in southeastern Wisconsin streams

USGS Publications Warehouse

Stepenuck, K.F.; Crunkilton, R.L.; Wang, L.

2002-01-01

Macroinvertebrates were used to assess the impact of urbanization on stream quality across a gradient of watershed imperviousness in 43 southeastern Wisconsin streams. The percentage of watershed connected imperviousness was chosen as the urbanization indicator to examine impact of urban land uses on macroinvertebrate communities. Most urban land uses were negatively correlated with the Shannon diversity index, percent of pollution intolerant Ephemeroptera, Plecoptera, and Trichoptera individuals, and generic richness. Nonurban land uses were positively correlated with these same metrics. The Hilsenhoff biotic index indicated that stream quality declined with increased urbanization. Functional feeding group metrics varied across a gradient of urbanization, suggesting changes in stream quality. Proportions of collectors and gatherers increased, while proportions of filterers, scrapers, and shredders decreased with increased watershed imperviousness. This study demonstrated that urbanization severely degraded stream macroinvertebrate communities, hence stream quality. Good stream quality existed where imperviousness was less than 8 percent, but less favorable assessments were inevitable where imperviousness exceeded 12 to 20 percent. Levels of imperviousness between 8 and 12 percent represented a threshold where minor increases in urbanization were associated with sharp declines in stream quality.

A baseline lunar mine

NASA Technical Reports Server (NTRS)

Gertsch, Richard E.

1992-01-01

A models lunar mining method is proposed that illustrates the problems to be expected in lunar mining and how they might be solved. While the method is quite feasible, it is, more importantly, a useful baseline system against which to test other, possible better, methods. Our study group proposed the slusher to stimulate discussion of how a lunar mining operation might be successfully accomplished. Critics of the slusher system were invited to propose better methods. The group noted that while nonterrestrial mining has been a vital part of past space manufacturing proposals, no one has proposed a lunar mining system in any real detail. The group considered it essential that the design of actual, workable, and specific lunar mining methods begin immediately. Based on an earlier proposal, the method is a three-drum slusher, also known as a cable-operated drag scraper. Its terrestrial application is quite limited, as it is relatively inefficient and inflexible. The method usually finds use in underwater mining from the shore and in moving small amounts of ore underground. When lunar mining scales up, the lunarized slusher will be replaced by more efficient, high-volume methods. Other aspects of lunar mining are discussed.

Depth and substratum differentiations among coexisting herbivorous cichlids in Lake Tanganyika

PubMed Central

Ochi, Haruki

2016-01-01

Cichlid fish in Lake Tanganyika represent a system of adaptive radiation in which eight ancestral lineages have diversified into hundreds of species through adaptation to various niches. However, Tanganyikan cichlids have been thought to be oversaturated, that is, the species number exceeds the number of niches and ecologically equivalent and competitively even species coexist. However, recent studies have shed light on niche segregation on a finer scale among apparently equivalent species. We observed depth and substratum preferences of 15 herbivorous cichlids from four ecomorphs (i.e. grazer, browser, scraper and scooper) on a rocky littoral slope for 14 years. Depth differentiation was detected among grazers that defended feeding territories and among browsers with feeding territories. Cichlid species having no feeding territory also showed specificity on depth and substratum, resulting in habitat segregation among species that belong to the same ecomorph. Phylogenetically close species did not occupy adjacent depths, nor the opposite depth zones. Our findings suggest that apparently equivalent species of the same ecomorph coexist parapatrically along depth on a few-metre scale, or coexist with different substratum preferences on the rocky shore, and this niche segregation may have been acquired by competition between encountering equivalent species through repetitive lake-level fluctuations. PMID:28018609

Ecology of ephemeroptera, plecoptera and trichoptera (insecta) in rivers of the gunung jerai forest reserve: diversity and distribution of functional feeding groups.

PubMed

Hamid, Suhaila Ab; Md Rawi, Che Salmah

2014-08-01

A field study was performed to describe the functional feeding groups (FFGs) of Ephemeroptera, Plecoptera and Trichoptera (EPT) in the Tupah, Batu Hampar and Teroi Rivers in the Gunung Jerai Forest Reserve (GJFR), Kedah, Malaysia. Twenty-nine genera belonging to 19 families were identified. The EPTs were classified into five FFGs: collector-gatherers (CG), collector-filterers (CF), shredders (SH), scrapers (SC) and predators (P). In this study, CG and CF were the dominant groups inhabiting all three rivers. Ephemeroptera dominated these rivers due to their high abundance, and they were also the CG (90.6%). SC were the lowest in abundance among all groups. Based on the FFGs, the Teroi River was suitable for CG, whereas the Tupah and Batu Hampar Rivers were suitable for CG and CF. The distribution of FFGs differed among the rivers (CG, χ(2) = 23.6, p = 0.00; SH, χ(2) = 10.02, p = 0.007; P, χ(2) = 25.54, p = 0.00; CF, χ(2) = 21.95, p = 0.00; SC, χ(2) = 9.31, p = 0.01). These findings indicated that the FFGs found in rivers of the GJFR represent high river quality.

Secondary production of benthic insects in three cold-desert streams

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

Gaines, W.L.

1987-07-01

Aquatic insect production was studied in three cold-desert streams in eastern Washington (Douglas Creek, Snively Springs, and Rattlesnake Springs). The size-frequency method was applied to individual taxa to estimate total insect production. production was also assessed for functional groups and trophic levels in each stream. Optioservus sp. (riffle beetles) and Baetis sp. (mayflies) accounted for 72% of the total insect numbers and 50% of the total biomass in Douglas Creek. Baetis sp. accounted for 42% of the total insect numbers and 25% of the total biomass in Snively Springs. Simulium sp. (blackflies) and Baetis sp. comprised 74% of the totalmore » insect numbers and 55% of the total biomass in Rattlesnake Springs. Grazer-scrapers (49%) and collectors (48%) were the most abundant functional groups in Douglas Creek. Collectors were the most abundant functional group in Snively Springs and Rattlesnake Springs. Herbivores and detritivores were the most abundant trophic level in Snively Springs and Rattlesnake Springs. Dipterans (midges and blackflies) were the most productive taxa within the study streams, accounting for 40% to 70% of the total community production. Production by collectors and detritivores was the highest of all functional groups and trophic levels in all study streams.« less

Transplanting and establishment of western snowberry (Symphoricarpos occidentalis Hook.) on reclaimed land

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

Friedlander, J.D.

1995-09-01

Reestablishment of western snowberry (Symphoricarpos occidentalis Hook.) was attempted on surface mined land reclaimed to mixed grass prairie in western North Dakota. Undisturbed shrub patches were segregated and removed with tractor scrapers in 1989. These were directly replaced in two low drainage landscape sites, less than one hectare each, on reclaimed land. No seeding, herbicide spraying, or grazing was conducted on reclaimed sites. Stem counts and frequency were analyzed yearly. Regression correlations were calculated for average stems/0.25m{sup 2}vs. April-July precipitation (r{sup 2} = 0.90), vs. October-July precipitation (r{sup 2} = 0.97), and vs. age of reclaimed stand (r{sup 2} =more » 0.58). Regression correlations were also calculated for frequency vs. April-July precipitation (r{sup 2} = 0.80), vs. October-July precipitation (r{sup 2} = 0.88), and vs. age of reclaimed stand (r{sup 2} = 0.58). October-July precipitation had the greatest impact on stand establishment and success. Special consideration should be given to site location and moisture conditions when transplanting western snowberry. Bond liability period length should be based on moisture conditions, not age of the stand.« less

Distribution of 137Cs in surface soil of Fraser's Hill, Pahang, Malaysia

NASA Astrophysics Data System (ADS)

Bakar, Ahmad Sanadi Abu; Hamzah, Zaini; Saat, Ahmad

2017-01-01

Caesium-137 (137Cs) in an anthropogenic radionuclide originated from the fission of fissile materials. Nuclear weapons testing during the 1960s and the Chernobyl disaster introduced substantial amount of 137Cs into the atmosphere that are then eventually deposited back to earth's surface. Caesium-137 can be used as tracer to study soil movements since it adsorbs to soil particles. This paper aims to describe the distribution of 137Cs in surface soil of Fraser's Hill, Pahang, determine the levels of 137Cs here compared to other areas, and to check correlation of 137Cs levels to physical data. A series of sampling were carried out between February 2014 and August 2015. Soil samples were taken from 31 locations using soil scraper. The samples were then taken to the laboratory to be dried, homogenized, grinded and sieved. The activity concentration of 137Cs in the samples was determined using gamma spectroscopy. The activity concentration was found to be between 0.26 Bq/kg and 5.14 Bq/kg. Although this paper only studies surface soil, 137Cs is expected to be present within the soil body. Further study of 137Cs in the soil body can be used to predictive model for soil erosion.

How low can you go? Impacts of a low-flow disturbance on aquatic insect communities.

PubMed

Walters, Annika W; Post, David M

2011-01-01

The natural hydrology of streams and rivers is being extensively modified by human activities. Water diversion, dam construction, and climate change have the potential to increase the frequency and intensity of low-flow events. Flow is a dominant force structuring stream aquatic insect communities, but the impacts of water diversion are poorly understood. Here we report results of an experimental stream flow diversion designed to test how aquatic insect communities respond to a low-flow disturbance. We diverted 40% to 80% of the water in three replicate streams for three summers, leading to summer flow exceedance probabilities of up to 99.9%. Shifts in habitat availability appeared to be a major driver of aquatic insect community responses. Responses also varied by habitat type: total insect density decreased in riffle habitats, but there was no change in pool habitats. Overall, the total biomass of aquatic insects decreased sharply with lowered flow. Collector-filterers, collector-gatherers, and scrapers were especially susceptible, while predatory insects were more resistant. Despite extremely low flow levels, there was no shift in aquatic insect family richness. The experimental water withdrawal did not increase water temperature or decrease water quality, and some wetted habitat was always maintained, which likely prevented more severe impacts on aquatic insect communities.

Associations of aquatic invertebrates and water quality in the ecology of an emerging tropical disease

NASA Astrophysics Data System (ADS)

Benbow, M.; Merritt, R. W.; Kimbirauskas, R.; Kolar, R.

2005-05-01

Mycobacterium ulcerans Infection is commonly called Buruli ulcer, a rapidly emerging skin disease that is often disfiguring and causes severe and lasting morbidity in developing nations of the tropics and sub-tropics. Outbreaks of BU are nearly always associated with slow-flowing aquatic habitats affected by human-mediated landscape changes, and biting aquatic insects are thought to play a role in transmission. As a part of a World Health Organization initiative, we are determining landscape factors that determine water quality conditions conducive for enhanced M. ulcerans growth and abundance in the aquatic environment. In June 2004 we collected water quality and invertebrate data from 12 water bodies near Accra, Ghana, Africa. Preliminary analyses found predator-dominated communities (from 47% - 64%) with Hemiptera (e.g., Belostomatidae and Naucoridae) most often collected. Using exploratory canonical correspondence analysis, sites separated out by functional feeding groups and water quality variables. Higher water hardness and total suspended solids was most associated with scrapers (i.e., snails) and shrimp, respectively. PCR evidence suggests that M. ulcerans is found among snails, fish and invertebrates. Future studies are proposed that take a multi-scale, multidisciplinary approach for identifying disturbance metrics that can be used to predict human Buruli ulcer incidence near monitored water bodies.

Longitudinal Changes in Physical Habitat and Macroinvertebrate Assemblages Along a Neotropical Stream Continuum

NASA Astrophysics Data System (ADS)

Colon-Gaud, C.; Whiles, M. R.

2005-05-01

Information on the structure and function of upland Neotropical streams is lacking compared to many other regions. We examined habitat characteristics and macroinvertebrate assemblages along an 8-km stretch of a stream originating on the continental divide in central Panama in order to examine patterns along a stream continuum. Wetted width and discharge ranged from 1 m and 18 L/s, respectively in the uppermost headwaters to 12 m and 1,580 L/s, respectively at the lowest reach examined. Percent substrate composition showed a decrease in fine particle sizes from upper headwater reaches (38%) to the lowest reach (10%). A total of 61 macroinvertebrate taxa were identified along the continuum, with more taxa present in lower reaches (45) compared to headwaters (28), but responses of individual groups varied. Trichoptera, Ephemeroptera, and Diptera richness increased from headwaters to the lowest site, whereas Hemiptera and Coleoptera richness decreased along the gradient. Collector-gatherers and predators were the dominant functional groups (~70% of total abundance) and changed little across sites. Shredder abundance was highest in headwaters (15% of total), while scrapers (20%) and collector/filterers (11%) peaked in the lower reaches. These patterns suggest that upland streams in this region follow basic tenets of the River Continuum Concept.

Diagnostic Systems Plan for the Advanced Light Source Top-OffUpgrade

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

Barry, Walter; Chin, Mike; Robin, David

2005-05-10

The Advanced Light Source (ALS) will soon be upgraded to enable top-off operations [1], in which electrons are quasi-continuously injected to produce constant stored beam current. The upgrade is structured in two phases. First, we will upgrade our injector from 1.5 GeV to 1.9 GeV to allow full energy injection and will start top-off operations. In the second phase, we will upgrade the Booster Ring (BR) with a bunch cleaning system to allow high bunch purity top-off injection. A diagnostics upgrade will be crucial for success in both phases of the top-off project, and our plan for it is describedmore » in this paper. New booster ring diagnostics will include updated beam position monitor (BPM) electronics, a tune monitoring system, and a new scraper. Two new synchrotron light monitors and a beam stop will be added to the booster-to-storage ring transfer line (BTS), and all the existing beam current monitors along the accelerator chain will be integrated into a single injection efficiency monitoring application. A dedicated bunch purity monitor will be installed in the storage ring (SR). Together, these diagnostic upgrades will enable smooth commissioning of the full energy injector and a quick transition to high quality top-off operation at the ALS.« less

Ecology of Ephemeroptera, Plecoptera and Trichoptera (Insecta) in Rivers of the Gunung Jerai Forest Reserve: Diversity and Distribution of Functional Feeding Groups

PubMed Central

Hamid, Suhaila Ab; Md Rawi, Che Salmah

2014-01-01

A field study was performed to describe the functional feeding groups (FFGs) of Ephemeroptera, Plecoptera and Trichoptera (EPT) in the Tupah, Batu Hampar and Teroi Rivers in the Gunung Jerai Forest Reserve (GJFR), Kedah, Malaysia. Twenty-nine genera belonging to 19 families were identified. The EPTs were classified into five FFGs: collector-gatherers (CG), collector-filterers (CF), shredders (SH), scrapers (SC) and predators (P). In this study, CG and CF were the dominant groups inhabiting all three rivers. Ephemeroptera dominated these rivers due to their high abundance, and they were also the CG (90.6%). SC were the lowest in abundance among all groups. Based on the FFGs, the Teroi River was suitable for CG, whereas the Tupah and Batu Hampar Rivers were suitable for CG and CF. The distribution of FFGs differed among the rivers (CG, χ2 = 23.6, p = 0.00; SH, χ2 = 10.02, p = 0.007; P, χ2 = 25.54, p = 0.00; CF, χ2 = 21.95, p = 0.00; SC, χ2 = 9.31, p = 0.01). These findings indicated that the FFGs found in rivers of the GJFR represent high river quality. PMID:25210588

Scraped surface heat exchangers.

PubMed

Rao, Chetan S; Hartel, Richard W

2006-01-01

Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs.

Global assessment of the status of coral reef herbivorous fishes: evidence for fishing effects.

PubMed

Edwards, C B; Friedlander, A M; Green, A G; Hardt, M J; Sala, E; Sweatman, H P; Williams, I D; Zgliczynski, B; Sandin, S A; Smith, J E

2014-01-07

On coral reefs, herbivorous fishes consume benthic primary producers and regulate competition between fleshy algae and reef-building corals. Many of these species are also important fishery targets, yet little is known about their global status. Using a large-scale synthesis of peer-reviewed and unpublished data, we examine variability in abundance and biomass of herbivorous reef fishes and explore evidence for fishing impacts globally and within regions. We show that biomass is more than twice as high in locations not accessible to fisheries relative to fisheries-accessible locations. Although there are large biogeographic differences in total biomass, the effects of fishing are consistent in nearly all regions. We also show that exposure to fishing alters the structure of the herbivore community by disproportionately reducing biomass of large-bodied functional groups (scraper/excavators, browsers, grazer/detritivores), while increasing biomass and abundance of territorial algal-farming damselfishes (Pomacentridae). The browser functional group that consumes macroalgae and can help to prevent coral-macroalgal phase shifts appears to be most susceptible to fishing. This fishing down the herbivore guild probably alters the effectiveness of these fishes in regulating algal abundance on reefs. Finally, data from remote and unfished locations provide important baselines for setting management and conservation targets for this important group of fishes.

The Storage Cell for the Tri-Experiment at COSY-JÜLICH

NASA Astrophysics Data System (ADS)

Felden, O.; Gebel, R.; Glende, M.; Lehrach, A.; Maier, R.; Prasuhn, D.; von Rossen, P.; Bisplinghoff, J.; Eversheim, P. D.; Hinterberger, F.

2002-04-01

At the EDDA experiment in the cooler synchrotron COSY in Jülich an atomic beam target is used which provides the designed polarization and density distribution. To increase the target density significantly a storage cell has been developed and implemented. This will contribute to a higher accuracy for the test of Time Reversal Invariance (TRI) which will be performed at the EDDA target place. To obtain the higher luminosity the target density and the transmission of the COSY beam through the cell were determined in their dependence on the cell aperture. Low storage cell apertures increase the target density in the cell but reduce the transmission of the circulating proton beam. To find the optimal cell design the transmission of the COSY beam was measured with movable scrapers and tested with an aperture at EDDA simulating the storage cell. The target density was calculated by Monte Carlo simulations for several cell geometries. An additional gain in target density is achieved by cooling the cell. A Teflon coating of the cell reduces depolarization of the target gas. First measurements with the EDDA detector have shown that the target density as well as the polarization are within the range of the expected values.

Perspective of Muon Production Target at J-PARC MLF MUSE

NASA Astrophysics Data System (ADS)

Makimura, Shunsuke; Matoba, Shiro; Kawamura, Naritoshi; Matsuzawa, Yukihiro; Tabe, Masato; Aoyagi, Hiroyuki; Kondo, Hiroto; Kobayashi, Yasuo; Fujimori, Hiroshi; Ikedo, Yutaka; Kadono, Ryosuke; Koda, Akihiro; Kojima, Kenji M.; Miyake, Yasuhiro; Nakamura, Jumpei G.; Oishi, Yu; Okabe, Hirotaka; Shimomura, Koichiro; Strasser, Patrick

A pulsed muon beam with unprecedented intensity will be generated by a 3-GeV 333-microA proton beam on a muon target made of 20-mm thick isotropic graphite at J-PARC MLF MUSE (Muon Science Establishment). The first muon beam was successfully generated on September 26th, 2008. Gradually upgrading the beam intensity, continuous 300-kW proton beam has been operated by a fixed target method without replacements till June of 2014. However, the lifetime of the fixed target was anticipated to be less than 1 year by the proton-irradiation damage of the graphite through 1-MW beam operation. To extend the lifetime, a muon rotating target, in which the radiation damage is distributed to a wider area, was installed in September of 2014, and continuous and stable operation has been successfully performed. Because the muon target becomes highly radioactive by the proton irradiation, the maintenance is conducted by remote handling in the Hot cell. In September of 2015, a scraper No. 1 to collimate the proton beam scattered by the target was replaced for further high-power beam operation. Recently, new developments on monitoring and maintenance of the muon target for higher power operation are in progress. In this article, perspective of muon production target at J-PARC MLF MUSE will be described.

The archaeology of drill hole U20bc, Nevada Test Site, Nye County, Nevada

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

McLane, A.R.; Hemphill, M.L.; Livingston, S.J.

1992-12-31

Impacts to four sites near drill hole U20bc on Pahute Mesa in the northwestern part of the Nevada Test Site were mitigated through data recovery. The work was done during 1988 by the Desert Research Institute for the Department of Energy, Nevada Field Office (DOE/NV)- The four sites that warranted data recovery were 26NY3171, 26NY3173, 26NY5561 and 26NY5566. These sites had previously been determined eligible to the National Register of Historic Places. They were temporary camps that contained lithic debitage, projectile points, milling stones and pottery, and therefore contributed significant information concerning the prehistory of the area. The study ofmore » the archaeological remains shows that the prehistoric people subsisted on plant foods and game animals as determined by the artifacts including manos, metates, pottery, lithic scrapers, and projectile points. The time sensitive arfifacts (pottery and diagnostic points) suggest that the region was used from about 12,000 B.P. to just before the historic period, possibly 150 years ago. DOE/NV has met its obligation to mitigate adverse impacts to the cultural resources at U20bc. Therefore, it is recommended that this project proceed as planned.« less

The archaeology of drill hole U20bc, Nevada Test Site, Nye County, Nevada

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

McLane, A.R.; Hemphill, M.L.; Livingston, S.J.

1992-01-01

Impacts to four sites near drill hole U20bc on Pahute Mesa in the northwestern part of the Nevada Test Site were mitigated through data recovery. The work was done during 1988 by the Desert Research Institute for the Department of Energy, Nevada Field Office (DOE/NV)- The four sites that warranted data recovery were 26NY3171, 26NY3173, 26NY5561 and 26NY5566. These sites had previously been determined eligible to the National Register of Historic Places. They were temporary camps that contained lithic debitage, projectile points, milling stones and pottery, and therefore contributed significant information concerning the prehistory of the area. The study ofmore » the archaeological remains shows that the prehistoric people subsisted on plant foods and game animals as determined by the artifacts including manos, metates, pottery, lithic scrapers, and projectile points. The time sensitive arfifacts (pottery and diagnostic points) suggest that the region was used from about 12,000 B.P. to just before the historic period, possibly 150 years ago. DOE/NV has met its obligation to mitigate adverse impacts to the cultural resources at U20bc. Therefore, it is recommended that this project proceed as planned.« less

Herd-level risk factors for hock injuries in freestall-housed dairy cows in the northeastern United States and California.

PubMed

Barrientos, A K; Chapinal, N; Weary, D M; Galo, E; von Keyserlingk, M A G

2013-06-01

The aim of this study was to investigate the associations between management and facility design factors and the prevalence of hock injuries in high-producing dairy cows in 76 freestall herds in the northeastern United States (NE-US; Vermont, New York, Pennsylvania) and California (CA). One group of high-production multiparous cows was monitored on each farm, and data on management, facility and stall design, and the conditions of the hocks were collected. Focal cows [n=38 ± 3 (mean ± standard deviation)] were evaluated for hock injuries using a 3-point scale (where 1=healthy and 3=evidently swollen or severe injury). Measures associated with the proportion (logit-transformed) of cows having injuries (score ≥ 2) or severe injuries (score=3) at the univariable level were submitted to multivariable general linear models. In NE-US, overall hock injuries increased with the percentage of stalls with fecal contamination [odds ratio (OR)=1.26; 95% confidence interval (CI)=1.02-1.54, for a 10% increase], and with the use of sawdust as bedding (OR=3.47; CI=1.14-10.62), and decreased with deep bedding (i.e., at least 10 cm depth of any type of bedding; OR=0.05; CI=0.02-0.14), use of sand as bedding (OR=0.06; CI=0.02-0.15), bedding dry matter (DM) ≥ 83.9% (OR=0.08; CI=0.03-0.20), and access to pasture during the dry period (OR=0.17; CI=0.05-0.53). When these variables were submitted to a multivariable model, the presence of deep bedding was the only factor that remained significant, explaining 54% of the variation in overall injuries. Severe hock injuries increased with the use of automatic scrapers (OR=2.29; CI=1.11-4.71) and the percentage of stalls with fecal contamination (OR=1.14; CI=1.00-1.31, for a 10% increase), and decreased with sand bedding (OR=0.22; CI=0.10-0.49), deep bedding (OR=0.24; CI=0.11-0.52), bedding DM ≥ 83.9% (OR=0.28; CI=0.14-0.58), and access to pasture during the dry period (OR=0.42; CI=0.18-0.97). The final multivariable model, which explained 36% of the variation in severe hock injuries, included the use of automatic scrapers and deep bedding. In CA, stall stocking density (OR=1.41; CI=1.00-2.01, for a 10% increase) and poor bedding maintenance (OR=1.08; CI=1.01-1.16, for a 2.5-cm decrease in depth of deep-bedded stalls) were associated with an increase of overall and severe hock injuries, respectively. Deep-bedded and well-maintained stalls reduce the risk of hock injuries. Regional variation in risk factors for these injuries should be considered when formulating on-farm recommendations. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Responses of macroinvertebrate community metrics to a wastewater discharge in the Upper Blue River of Kansas and Missouri, USA

USGS Publications Warehouse

Poulton, Barry C.; Graham, Jennifer L.; Rasmussen, Teresa J.; Stone, Mandy L.

2015-01-01

The Blue River Main wastewater treatment facility (WWTF) discharges into the upper Blue River (725 km2), and is recently upgraded to implement biological nutrient removal. We measured biotic condition upstream and downstream of the discharge utilizing the macroinvertebrate protocol developed for Kansas streams. We examined responses of 34 metrics to determine the best indicators for discriminating site differences and for predicting biological condition. Significant differences between sites upstream and downstream of the discharge were identified for 15 metrics in April and 12 metrics in August. Upstream biotic condition scores were significantly greater than scores at both downstream sites in April (p = 0.02), and in August the most downstream site was classified as non-biologically supporting. Thirteen EPT taxa (Ephemeroptera, Plecoptera, Trichoptera) considered intolerant of degraded stream quality were absent at one or both downstream sites. Increases in tolerance metrics and filtering macroinvertebrates, and a decline in ratio of scrapers to filterers all indicated effects of increased nutrient enrichment. Stepwise regressions identified several significant models containing a suite of metrics with low redundancy (R2 = 0.90 - 0.99). Based on the rapid decline in biological condition downstream of the discharge, the level of nutrient removal resulting from the facility upgrade (10% - 20%) was not enough to mitigate negative effects on macroinvertebrate communities.

Long-term change in limnology and invertebrates in Alaskan boreal wetlands

USGS Publications Warehouse

Corcoran, R.M.; Lovvorn, J.R.; Heglund, P.J.

2009-01-01

Climate change is more pronounced at high northern latitudes, and may be affecting the physical, chemical, and biological attributes of the abundant wetlands in boreal forests. On the Yukon Flats, located in the boreal forest of northeast Alaska, wetlands originally sampled during 1985-1989 were re-sampled for water chemistry and macroinvertebrates in summer 2001-2003. Wetlands sampled lost on average 19% surface water area between these periods. Total nitrogen and most metal cations (Na, Mg, and Ca, but not K) increased between these periods, whereas total phosphorus and chlorophyll a (Chl a) declined. These changes were greater in wetlands that had experienced more drying (decreased surface area). Compared with 1985-1989, densities of cladocerans, copepods, and ostracods in both June and August were much higher in 2002-2003, whereas densities of amphipods, gastropods, and chironomid larvae were generally lower. In comparisons among wetlands in 2002-2003 only, amphipod biomass was lower in wetlands with lower Chl a, which might help explain the decline of amphipods since the late 1980s when Chl a was higher. The decline in Chl a corresponded to greatly increased zooplankton density in June, suggesting a shift in carbon flow from scrapers and deposit-feeders to water-column grazers. Declines in benthic and epibenthic deposit-feeding invertebrates suggest important food web effects of climate change in otherwise pristine wetlands of the boreal forest. ?? 2008 Springer Science+Business Media B.V.

Local Helicity Injection Systems for Non-solenoidal Startup in the PEGASUS Toroidal Experiment

NASA Astrophysics Data System (ADS)

Perry, J. M.; Barr, J. L.; Bongard, M. W.; Fonck, R. J.; Hinson, E. T.; Lewicki, B. T.; Redd, A. J.

2013-10-01

Local helicity injection is being developed in the PEGASUS Toroidal Experiment for non-solenoidal startup in spherical tokamaks. The effective loop voltage due to helicity injection scales with the area of the injectors, requiring the development of electron current injectors with areas much larger than the 2 cm2 plasma arc injectors used to date. Solid and gas-effused metallic electrodes were found to be unusable due to reduced injector area utilization from localized cathode spots and narrow operational regimes. An integrated array of 8 compact plasma arc sources is thus being developed for high current startup. It employs two monolithic power systems, for the plasma arc sources and the bias current extraction system. The array effectively eliminates impurity fueling from plasma-material interaction by incorporating a local scraper-limiter and conical-frustum bias electrodes to mitigate the effects of cathode spots. An energy balance model of helicity injection indicates that the resulting 20 cm2 of total injection area should provide sufficient current drive to reach 0.3 MA. At that level, helicity injection drive exceeds that from poloidal induction, which is the relevant operational regime for large-scale spherical tokamaks. Future placement of the injector array near an expanded boundary divertor region will test simultaneous optimization of helicity drive and the Taylor relaxation current limit. Work supported by US DOE Grant DE-FG02-96ER54375.

Evaluations of in-use emission factors from off-road construction equipment

NASA Astrophysics Data System (ADS)

Cao, Tanfeng; Durbin, Thomas D.; Russell, Robert L.; Cocker, David R.; Scora, George; Maldonado, Hector; Johnson, Kent C.

2016-12-01

Gaseous and particle emissions from construction engines contribute an important fraction of the total air pollutants released into the atmosphere and are gaining increasing regulatory attention. Robust quantification of nitrogen oxides (NOx) and particulate matter (PM) emissions are necessary to inventory the contribution of construction equipment to atmospheric loadings. Theses emission inventories require emissions factors from construction equipment as a function of equipment type and modes of operation. While the development of portable emissions measurement systems (PEMS) has led to increased studies of construction equipment emissions, emissions data are still much more limited than for on-road vehicles. The goal of this research program was to obtain accurate in-use emissions data from a test fleet of newer construction equipment (model year 2002 or later) using a Code of Federal Requirements (CFR) compliant PEMS system. In-use emission measurements were made from twenty-seven pieces of construction equipment, which included four backhoes, six wheel loaders, four excavators, two scrapers (one with two engines), six bulldozers, and four graders. The engines ranged in model year from 2003 to 2012, in rated horsepower (hp) from 92 to 540 hp, and in hours of operation from 24 to 17,149 h. This is the largest study of off-road equipment emissions using 40 CFR part 1065 compliant PEMS equipment for all regulated gaseous and particulate emissions.

Advancing High Current Startup via Localized Helicity Injection in the PEGASUS Toroidal Experiment

NASA Astrophysics Data System (ADS)

Hinson, E. T.; Barr, J. L.; Bongard, M. W.; Burke, M. G.; Fonck, R. J.; Perry, J. M.; Redd, A. J.; Schlossberg, D. J.

2013-10-01

Non-solenoidal startup via local helicity injection (LHI) and poloidal field induction is used to produce Ip = 0 . 17 MA tokamak discharges. Impurity contamination has been reduced to negligible levels by use of conical frustum cathode geometry and local scraper limiters. Attainable currents are governed by global limits of helicity and energy balance, and Taylor relaxation. A simple lumped parameter model based on these limits is used to project discharge evolution, and indicates that attaining 1 MA in NSTX-U will require LHI-driven effective loop voltages to dominate contributions from dLp / dt . This regime contrasts with results to date and will be tested at 0.3 MA in PEGASUS with a new integrated multi-injector array. Injector impedance characteristics are consistent with magnetically-limited regimes observed in higher-power foilless diodes. Bursts of MHD are measured on time scales of order ~ 100 μ s, and correlate with rapid equilibrium changes, discrete rises in Ip, redistribution of the toroidal current, ion heating (Ti ~ 1 keV), transient drops in injector voltage, and apparent n = 1 line-tied kink activity at the injector. NIMROD simulations of high-field-side HI discharges in PEGASUS are in qualitative agreement, suggesting Ip buildup results from inward propagating toroidal current loops created by intermittent reconnection of injected current streams. Work supported by US DOE Grant DE-FG02-96ER54375.

Electrorefining cell with parallel electrode/concentric cylinder cathode

DOEpatents

Gay, Eddie C.; Miller, William E.; Laidler, James J.

1997-01-01

A cathode-anode arrangement for use in an electrolytic cell is adapted for electrochemically refining spent nuclear fuel from a nuclear reactor and recovering purified uranium for further treatment and possible recycling as a fresh blanket or core fuel in a nuclear reactor. The arrangement includes a plurality of inner anodic dissolution baskets that are each attached to a respective support rod, are submerged in a molten lithium halide salt, and are rotationally displaced. An inner hollow cylindrical-shaped cathode is concentrically disposed about the inner anodic dissolution baskets. Concentrically disposed about the inner cathode in a spaced manner are a plurality of outer anodic dissolution baskets, while an outer hollow cylindrical-shaped is disposed about the outer anodic dissolution baskets. Uranium is transported from the anode baskets and deposited in a uniform cylindrical shape on the inner and outer cathode cylinders by rotating the anode baskets within the molten lithium halide salt. Scrapers located on each anode basket abrade and remove the spent fuel deposits on the surfaces of the inner and outer cathode cylinders, with the spent fuel falling to the bottom of the cell for removal. Cell resistance is reduced and uranium deposition rate enhanced by increasing the electrode area and reducing the anode-cathode spacing. Collection efficiency is enhanced by trapping and recovery of uranium dendrites scrapped off of the cylindrical cathodes which may be greater in number than two.

Electrorefining cell with parallel electrode/concentric cylinder cathode

DOEpatents

Gay, E.C.; Miller, W.E.; Laidler, J.J.

1997-07-22

A cathode-anode arrangement for use in an electrolytic cell is adapted for electrochemically refining spent nuclear fuel from a nuclear reactor and recovering purified uranium for further treatment and possible recycling as a fresh blanket or core fuel in a nuclear reactor. The arrangement includes a plurality of inner anodic dissolution baskets that are each attached to a respective support rod, are submerged in a molten lithium halide salt, and are rotationally displaced. An inner hollow cylindrical-shaped cathode is concentrically disposed about the inner anodic dissolution baskets. Concentrically disposed about the inner cathode in a spaced manner are a plurality of outer anodic dissolution baskets, while an outer hollow cylindrical-shaped is disposed about the outer anodic dissolution baskets. Uranium is transported from the anode baskets and deposited in a uniform cylindrical shape on the inner and outer cathode cylinders by rotating the anode baskets within the molten lithium halide salt. Scrapers located on each anode basket abrade and remove the spent fuel deposits on the surfaces of the inner and outer cathode cylinders, with the spent fuel falling to the bottom of the cell for removal. Cell resistance is reduced and uranium deposition rate enhanced by increasing the electrode area and reducing the anode-cathode spacing. Collection efficiency is enhanced by trapping and recovery of uranium dendrites scrapped off of the cylindrical cathodes which may be greater in number than two. 12 figs.

Concentrations of metals associated with mining waste in sediments, biofilm, benthic macroinvertebrates, and fish from the Coeur d'Alene River Basin, Idaho

USGS Publications Warehouse

Farag, A.M.; Woodward, D.F.; Goldstein, J.N.; Brumbaugh, W.; Meyer, J.S.

1998-01-01

Arsenic, Cd, Cu, Pb, Hg, and Zn were measured in sediments, biofilm, benthic macroinvertebrates, and fish from the Coeur d'Alene (CDA) River to characterize the pathway of metals transfer between these components. Metals enter the CDA Basin via tributaries where mining activities have occurred. In general, the ranking of food-web components from the greatest to smallest concentrations of metals was as follows: biofilm (the layer of abiotic and biotic material on rock surfaces) and sediments > invertebrates > whole fish. Elevated Pb was documented in invertebrates, and elevated Cd and Zn were documented in sediment and biofilm approximately 80 km downstream to the Spokane River. The accumulation of metals in invertebrates was dependent on functional feeding group and shredders-scrapers that feed on biofilm accumulated the largest concentrations of metals. Although the absolute concentrations of metals were the largest in biofilm and sediments, the metals have accumulated in fish approximately 50 km downstream from Kellogg, near the town of Harrison. While metals do not biomagnify between trophic levels, the metals in the CDA Basin are bioavailable and do biotransfer. Trout less than 100 mm long feed exclusively on small invertebrates, and small invertebrates accumulate greater concentrations of metals than large invertebrates. Therefore, early-lifestage fish may be exposed to a larger dose of metals than adults.

A Benthic Community Index for streams in the Northern Lakes and Forests Ecoregion

USGS Publications Warehouse

Butcher, Jason T.; Stewart, Paul M.; Simon, Thomas P.

2003-01-01

Encompassing the northern glaciated section of the Midwest United States, the Northern Lakes and Forests Ecoregion is characterized by mixed conifer and deciduous forests and wetlands. Sites were randomly selected in the ecoregion using the Environmental Protection Agency's Environmental Monitoring and Assessment Program designed to develop an index of biotic integrity for wadeable streams. Macroinvertebrates were sampled during the fall of 1998 and 1999 using a multi-habitat, composite-sample method. Two hundred forty-six invertebrate taxa in 97 families were collected from 94 sites. Ten of 42 candidate metrics satisfied metric selection criteria, including six structural metrics (number of Ephemeroptera taxa, number of Diptera taxa, richness, Shannon-Wiener diversity, percent Trichoptera abundance, and percent Crustacea and Mollusca abundance), two functional metrics (number of Filterer taxa and number of Scraper taxa), and two conditional metrics (number of Ephemeroptera, Trichoptera, and Plecoptera taxa and Hilsenhoff Biotic Index). These metrics were used to develop a Benthic Community Index to assess the biological integrity of wadeable streams in the ecoregion. Index values ranged from 10 to 50, and scores from impaired sites were significantly different than non-impaired sites (P<0.001). Index values were divided into three narrative interpretations of biological integrity (poor, fair, and good). After further testing, the index may provide a useful biological assessment tool for resource managers in the ecoregion.

Overview of the Conceptual Design of the Future VENUS Neutron Imaging Beam Line at the Spallation Neutron Source

NASA Astrophysics Data System (ADS)

Bilheux, Hassina; Herwig, Ken; Keener, Scott; Davis, Larry

VENUS (Versatile Neutron Imaging Beam line at the Spallation Neutron Source) will be a world-class neutron-imaging instrument that will uniquely utilize the Spallation Neutron Source (SNS) time-of-flight (TOF) capabilities to measure and characterize objects across several length scales (mm to μm). When completed, VENUS will provide academia, industry and government laboratories with the opportunity to advance scientific research in areas such as energy, materials, additive manufacturing, geosciences, transportation, engineering, plant physiology, biology, etc. It is anticipated that a good portion of the VENUS user community will have a strong engineering/industrial research focus. Installed at Beam line 10 (BL10), VENUS will be a 25-m neutron imaging facility with the capability to fully illuminate (i.e., umbra illumination) a 20 cm x 20 cm detector area. The design allows for a 28 cm x 28 cm field of view when using the penumbra to 80% of the full illumination flux. A sample position at 20 m will be implemented for magnification measurements. The optical components are comprised of a series of selected apertures, T0 and bandwidth choppers, beam scrapers, a fast shutter to limit sample activation, and flight tubes filled with Helium. Techniques such as energy selective, Bragg edge and epithermal imaging will be available at VENUS.

Middle Stone Age starch acquisition in the Niassa Rift, Mozambique

NASA Astrophysics Data System (ADS)

Mercader, Julio; Bennett, Tim; Raja, Mussa

2008-09-01

The quest for direct lines of evidence for Paleolithic plant consumption during the African Middle Stone Age has led scientists to study residues and use-wear on flaked stone tools. Past work has established lithic function through multiple lines of evidence and the spatial breakdown of use-wear and microscopic traces on tool surfaces. This paper focuses on the quantitative analysis of starch assemblages and the botanical identification of grains from flake and core tools to learn about human ecology of carbohydrate use around the Niassa woodlands, in the Mozambican Rift. The processing of starchy plant parts is deduced from the occurrence of starch assemblages that presumably got attached to stone tool surfaces by actions associated with extractive or culinary activities. Specifically, we investigate starch grains from stone tools recently excavated in northern Mozambique at the site of Mikuyu; which presumably spans the middle to late Pleistocene and represents similar sites found along the Malawi/Niassa corridor that links East, Southern, and Central Africa. Starch was extracted and processed with a diverse tool kit consisting of scrapers, cores, points, flakes, and other kinds of tools. The microbotanical data suggests consumption of seeds, legumes, caryopses, piths, underground storage organs, nuts, and mesocarps from more than a dozen families. Our data suggest a great antiquity for starch use in Africa as well as an expanded diet and intensification.

Fracked ecology: Response of aquatic trophic structure and mercury biomagnification dynamics in the Marcellus Shale Formation.

PubMed

Grant, Christopher James; Lutz, Allison K; Kulig, Aaron D; Stanton, Mitchell R

2016-12-01

Unconventional natural gas development and hydraulic fracturing practices (fracking) are increasing worldwide due to global energy demands. Research has only recently begun to assess fracking impacts to surrounding environments, and very little research is aimed at determining effects on aquatic biodiversity and contaminant biomagnification. Twenty-seven remotely-located streams in Pennsylvania's Marcellus Shale basin were sampled during June and July of 2012 and 2013. At each stream, stream physiochemical properties, trophic biodiversity, and structure and mercury levels were assessed. We used δ15N, δ13C, and methyl mercury to determine whether changes in methyl mercury biomagnification were related to the fracking occurring within the streams' watersheds. While we observed no difference in rates of biomagnificaion related to within-watershed fracking activities, we did observe elevated methyl mercury concentrations that were influenced by decreased stream pH, elevated dissolved stream water Hg values, decreased macroinvertebrate Index for Biotic Integrity scores, and lower Ephemeroptera, Plecoptera, and Trichoptera macroinvertebrate richness at stream sites where fracking had occurred within their watershed. We documented the loss of scrapers from streams with the highest well densities, and no fish or no fish diversity at streams with documented frackwater fluid spills. Our results suggest fracking has the potential to alter aquatic biodiversity and methyl mercury concentrations at the base of food webs.

A novel bone scraper for intraoral harvesting: a device for filling small bone defects.

PubMed

Zaffe, Davide; D'Avenia, Ferdinando

2007-08-01

To evaluate histologically the morphology and characteristics of bone chips harvested intraorally by Safescraper, a specially designed cortical bone collector. Bone chips harvested near a bone defect or in other intraoral sites were grafted into a post-extractive socket or applied in procedures for maxillary sinus floor augmentation or guided bone regeneration. Core biopsies were performed at implant insertion. Undecalcified specimens embedded in PMMA were studied by histology, histochemistry and SEM. Intraoral harvesting by Safescraper provided a simple, clinically effective regenerative procedure with low morbidity for collecting cortical bone chips (0.9-1.7 mm in length, roughly 100 microm thick). Chips had an oblong or quadrangular shape and contained live osteocytes (mean viability: 45-72%). Bone chip grafting produced newly formed bone tissue suitable for implant insertion. Trabecular bone volume measured on biopsies decreased with time (from 45-55% to 23%). Grafted chips made up 50% or less of the calcified tissue in biopsies. Biopsies presented remodeling activities, new bone formation by apposition and live osteocytes (35% or higher). In conclusion, Safescraper is capable of collecting adequate amounts of cortical bone chips from different intraoral sites. The procedure is effective for treating alveolar defects for endosseous implant insertion and provides good healing of small bone defects after grafting with bone chips. The study indicates that Safescraper is a very useful device for in-office bone harvesting procedures in routine peri-implant bone regeneration.

Treatment of oral malodour. Medium-term efficacy of mechanical and/or chemical agents: a systematic review.

PubMed

Slot, Dagmar E; De Geest, Sophie; van der Weijden, Fridus A; Quirynen, Marc

2015-04-01

What is the effect of a dentifrice (DF), a mouthwash (MW), tongue cleaning (TC), or any combination of these as adjunct to toothbrushing on intra-oral malodour and tongue coating as compared to toothbrushing alone in systemically healthy patients, when used for a minimum follow-up period of 2 weeks? The MEDLINE-PubMed, Cochrane-CENTRAL and EMBASE databases were searched up to August 2014. Measurements of Volatile Sulphur Compounds and organoleptic scores of oral malodour were selected as outcome variables. Data were extracted and a descriptive analysis was performed. Independent screening of 1054 unique papers resulted in 12 eligible clinical trials with a medium-term (≥2 weeks) duration. The majority of studies provided a significant reduction in oral malodour when evaluating products with an active ingredient (incorporated into a DF or a MW) used adjunctively to toothbrushing. The added value of tongue cleaning over a MW was evaluated in one study. Due to very limited evidence, the potential effect of a specifically formulated dentifrice, a mouthwash or a tongue scraper for treating oral malodour is, in general, unclear. For mouthwashes containing the active ingredients chlorhexidine + cetylpyridinium chloride + zinc (CHX + CPC + Zn) and zinc chloride + cetylpyridinium chloride (ZnCl + CPC) most evidence was available. The strength of a recommendation to use these products was graded to be 'weak'. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Development and validation of a macroinvertebrate index of biotic integrity (IBI) for assessing urban impacts to Northern California freshwater wetlands.

PubMed

Lunde, Kevin B; Resh, Vincent H

2012-06-01

Despite California policies requiring assessment of ambient wetland condition and compensatory wetland mitigations, no intensive monitoring tools have been developed to evaluate freshwater wetlands within the state. Therefore, we developed standardized, wadeable field methods to sample macroinvertebrate communities and evaluated 40 wetlands across Northern California to develop a macroinvertebrate index of biotic integrity (IBI). A priori reference sites were selected with minimal urban impacts, representing a best-attainable condition. We screened 56 macroinvertebrate metrics for inclusion in the IBI based on responsiveness to percent urbanization. Eight final metrics were selected for inclusion in the IBI: percent three dominant taxa; scraper richness; percent Ephemeroptera, Odonata, and Trichoptera (EOT); EOT richness; percent Tanypodinae/Chironomidae; Oligochaeta richness; percent Coleoptera; and predator richness. The IBI (potential range 0-100) demonstrated significant discriminatory power between the reference (mean = 69) and impacted wetlands (mean = 28). It also declined with increasing percent urbanization (R (2) = 0.53, p < 0.005) among wetlands in an independent validation dataset (n = 14). The IBI was robust in showing no significant bias with environmental gradients. This IBI is a functional tool to determine the ecological condition at urban (stormwater and flood control ponds), as well as rural freshwater wetlands (stockponds, seasonal wetlands, and natural ponds). Biological differences between perennial and non-perennial wetlands suggest that developing separate indicators for these wetland types may improve applicability, although the existing data set was not sufficient for exploring this option.

A Multimetric Benthic Macroinvertebrate Index for the Assessment of Stream Biotic Integrity in Korea

PubMed Central

Jun, Yung-Chul; Won, Doo-Hee; Lee, Soo-Hyung; Kong, Dong-Soo; Hwang, Soon-Jin

2012-01-01

At a time when anthropogenic activities are increasingly disturbing the overall ecological integrity of freshwater ecosystems, monitoring of biological communities is central to assessing the health and function of streams. This study aimed to use a large nation-wide database to develop a multimetric index (the Korean Benthic macroinvertebrate Index of Biological Integrity—KB-IBI) applicable to the biological assessment of Korean streams. Reference and impaired conditions were determined based on watershed, chemical and physical criteria. Eight of an initial 34 candidate metrics were selected using a stepwise procedure that evaluated metric variability, redundancy, sensitivity and responsiveness to environmental gradients. The selected metrics were number of taxa, percent Ephemeroptera-Plecoptera-Trichoptera (EPT) individuals, percent of a dominant taxon, percent taxa abundance without Chironomidae, Shannon’s diversity index, percent gatherer individuals, ratio of filterers and scrapers, and the Korean saprobic index. Our multimetric index successfully distinguished reference from impaired conditions. A scoring system was established for each core metric using its quartile range and response to anthropogenic disturbances. The multimetric index was classified by aggregating the individual metric ..scores and the value range was quadrisected to provide a narrative criterion (Poor, Fair, Good and Excellent) to describe the biological integrity of the streams in the study. A validation procedure showed that the index is an effective method for evaluating stream conditions, and thus is appropriate for use in future studies measuring the long-term status of streams, and the effectiveness of restoration methods. PMID:23202765

Mechanisms of high-frequency song generation in brachypterous crickets and the role of ghost frequencies.

PubMed

Robillard, Tony; Montealegre-Z, Fernando; Desutter-Grandcolas, Laure; Grandcolas, Philippe; Robert, Daniel

2013-06-01

Sound production in crickets relies on stridulation, the well-understood rubbing together of a pair of specialised wings. As the file of one wing slides over the scraper of the other, a series of rhythmic impacts causes harmonic oscillations, usually resulting in the radiation of pure tones delivered at low frequencies (2-8 kHz). In the short-winged crickets of the Lebinthini tribe, acoustic communication relies on signals with remarkably high frequencies (>8 kHz) and rich harmonic content. Using several species of the subfamily Eneopterinae, we characterised the morphological and mechanical specialisations supporting the production of high frequencies, and demonstrated that higher harmonics are exploited as dominant frequencies. These specialisations affect the structure of the stridulatory file, the motor control of stridulation and the resonance of the sound radiator. We placed these specialisations in a phylogenetic framework and show that they serve to exploit high-frequency vibrational modes pre-existing in the phylogenetic ancestor. In Eneopterinae, the lower frequency components are harmonically related to the dominant peak, suggesting they are relicts of ancestral carrier frequencies. Yet, such ghost frequencies still occur in the wings' free resonances, highlighting the fundamental mechanical constraints of sound radiation. These results support the hypothesis that such high-frequency songs evolved stepwise, by a form of punctuated evolution that could be related to functional constraints, rather than by only the progressive increase of the ancestral fundamental frequency.

Membrane Peeling-Induced Retinal Alterations on Intraoperative OCT in Vitreomacular Interface Disorders From the PIONEER Study.

PubMed

Ehlers, Justis P; Han, Jaehong; Petkovsek, Daniel; Kaiser, Peter K; Singh, Rishi P; Srivastava, Sunil K

2015-11-01

To assess retinal architectural alterations that occur following membrane peeling procedures and the impact of peel technique on these alterations utilizing intraoperative optical coherence tomography (iOCT). This is a subanalysis of the prospective PIONEER iOCT study of eyes undergoing a membrane peeling for a vitreomacular interface (VMI) disorder. Intraoperative scanning was performed with a microscope-mounted OCT system. Macroarchitectural alterations (e.g., full-thickness retinal elevations) and microarchitectural alterations (e.g., relative layer thickness alterations) were analyzed. Video/iOCT correlation was performed to identify instrument-tissue manipulations resulting in macroarchitectural alterations. One hundred sixty-three eyes were included in the macroarchitectural analysis. Instrumentation utilized for membrane peeling included forceps alone for 73 eyes (45%), combined diamond-dusted membrane scraper (DDMS) and forceps for 87 eyes (53%), and other techniques in three eyes (2%). Focal retinal elevations were identified in 45 of 163 eyes (28%). Video/iOCT correlation identified 69% of alterations involved forceps compared to 26% due to DDMS. Sixteen percent of retinal alterations persisted 1 month following surgery. The microarchitectural analysis included 134 eyes. Immediately following membrane peeling, there was a significant increase in the ellipsoid zone to retinal pigment epithelium height (+20%, P < 0.00001) and the cone outer segment tips to retinal pigment epithelium height (+18%, P < 0.00001). Significant subclinical retinal architectural changes occur during membrane peeling for VMI conditions. Differences in surgical instruments may impact these architectural alterations.

Cartilage engineering using chondrocyte cell sheets and its application in reconstruction of microtia.

PubMed

Zhou, Libin; Ding, Ruiying; Li, Baowei; Han, Haolun; Wang, Hongnan; Wang, Gang; Xu, Bingxin; Zhai, Suoqiang; Wu, Wei

2015-01-01

The imperfections of scaffold materials have hindered the clinical application of cartilage tissue engineering. The recently developed cell-sheet technique is adopted to engineer tissues without scaffold materials, thus is considered being potentially able to overcome the problems concerning the scaffold imperfections. This study constructed monolayer and bilayer chondrocyte cell sheets and harvested the sheets with cell scraper instead of temperature-responsive culture dishes. The properties of the cultured chondrocyte cell sheets and the feasibility of cartilage engineering using the chondrocyte cell sheets was further investigated via in vitro and in vivo study. Primary extracellular matrix (ECM) formation and type II collagen expression was detected in the cell sheets during in vitro culture. After implanted into nude mice for 8 weeks, mature cartilage discs were harvested. The morphology of newly formed cartilage was similar in the constructs originated from monolayer and bilayer chondrocyte cell sheet. The chondrocytes were located within evenly distributed ovoid lacunae. Robust ECM formation and intense expression of type II collagen was observed surrounding the evenly distributed chondrocytes in the neocartilages. Biochemical analysis showed that the DNA contents of the neocartilages were higher than native human costal cartilage; while the contents of the main component of ECM, glycosaminoglycan and hydroxyproline, were similar to native human costal cartilage. In conclusion, the chondrocyte cell sheet constructed using the simple and low-cost technique is basically the same with the cell sheet cultured and harvested in temperature-responsive culture dishes, and can be used for cartilage tissue engineering.

Analysis on the influence of forest soil characteristics on radioactive Cs infiltration and evaluation of residual radioactive Cs on surfaces.

PubMed

Mori, Yoshitomo; Yoneda, Minoru; Shimada, Yoko; Fukutani, Satoshi; Ikegami, Maiko; Shimomura, Ryohei

2018-03-29

We investigated the depth profiles of radioactive Cs, ignition loss, and cation exchange capacity (CEC) in five types of forest soils sampled using scraper plates. We then simulated the monitored depth profiles in a compartment model, taking ignition loss as a parameter based on experimental results showing a positive correlation between ignition loss and the CEC. The calculated values were comparable with the monitored values, though some discrepancy was observed in the middle of the soil layer. Based on decontamination data on the surface dose rate and surface contamination concentration, we newly defined a surface residual index (SRI) to evaluate the residual radioactive Cs on surfaces. The SRI value tended to gradually decrease in forests and unpaved roads and was much smaller in forests and on unpaved roads than on paved roads. The radioactive Cs was assumed to have already infiltrated underground 18 months after the nuclear power plant accident, and the sinking was assumed to be ongoing. The SRI values measured on paved roads suggested that radioactive Cs remained on the surfaces, though a gradual infiltration was observed towards the end of the monitoring term. The SRI value is thought to be effective in grasping the rough condition of residual radioactive Cs quickly at sites of decontamination activity in the field. The SRI value may be serviceable for actual contamination works after further research is done to elucidate points such as the relation between the SRI and the infiltration of radioactive Cs in various types of objects.

Analysis of Silicones Released from Household Items and Baby Articles by Direct Analysis in Real Time-Mass Spectrometry

NASA Astrophysics Data System (ADS)

Gross, Jürgen H.

2015-03-01

Direct analysis in real time-mass spectrometry (DART-MS) enables screening of articles of daily use made of polydimethylsiloxanes (PDMS), commonly known as silicone rubber, to assess their tendency to release low molecular weight silicone oligomers. DART-MS analyses were performed on a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Flexible silicone baking molds, a watch band, and a dough scraper, as baby articles different brands of pacifiers, nipples, and a teething ring have been examined. While somewhat arbitrarily chosen, the set can be regarded as representative of household items, baby articles, and other objects made of silicone rubber. For comparison, two brands of silicone septa and as blanks a glass slide and a latex pacifier were included. Differences between the objects were mainly observed in terms of molecular weight distribution and occasional release of other compounds in addition to PDMS. Other than that, all objects made of silicone rubber released significant amounts of PDMS during DART analysis. To provide a coarse quantification, a calibration based on silicone oil was established, which delivered PDMS losses from 20 μg to >100 μg during the 16-s period per measurement. Also, the extraction of baking molds in rapeseed oil demonstrated a PDMS release at the level of 1 μg mg-1. These findings indicate a potential health hazard from frequent or long-term use of such items. This work does not intend to blame certain brands of such articles. Nonetheless, a higher level of awareness of this source of daily silicone intake is suggested.

Habitats and trophic relationships of Chironomidae insect larvae from the Sepotuba River basin, Pantanal of Mato Grosso, Brazil.

PubMed

Butakka, C M M; Grzybkowska, M; Pinha, G D; Takeda, A M

2014-05-01

Benthic habitats are linked by physical processes and are essential elements in assessing of the distribution dynamics of Chironomidae dipteran insects and their role in aquatic ecosystems. This work presents results of distribution patterns of chironomids larvae in 38 sites that are abundant in the study site, inhabiting the substrate of the main river channel, rapids, tributary brook, floodplain lakes and reservoir along the Sepotuba River from its mouth at the Paraguay River to the headwater region. A total of 1,247 larvae was registered. The most abundant taxa were Polypedilum (Tripodura) sp. (25.2%), Cricotopus sp.3 (23.0%) and Tanytarsus sp. (15.0%). Fissimentum desiccatum were found only in the reservoir; Fissimentum sp.2 and Tanytarsus cf. T. obiriciae sp.2 in floodplain lakes, and Goeldichironomus sp. in the main channel. The low diversity of the sites S06 and S35 is caused by the near-exclusive presence of the species Cricotopus sp.3, alone or together with one or another taxon (Tanytarsus sp., Djalmabatista sp.3). Collectors-filterers represent 16%, collectors-gatherers 15%, predators 11% and scrapers only 1%. The predators dominated in the secondary channel (±88 ind/m2), corresponding to 40% of the total of this group. Cryptochironomus sp.2 (34%) and Ablasbemyia gr. annulata (26%) were the most abundant among the predators. The differences along the river course are decisive for the formation of distinct or discontinuous communities and the limits become obvious though the interrelations between the populations in the community, as for instance, competition for food and habitats.

Downstream effects of hydropower production on aquatic macroinvertebrate assemblages in two rivers in Costa Rica.

PubMed

Chaves-Ulloa, Ramsa; Umaña-Villalobos, Gerardo; Springer, Monika

2014-04-01

Despite the fact that little is known about the consequences of hydropower production in tropical areas, many large dams (> 15 m high) are currently under construction or consideration in the tropics. We researched the effects of large hydroelectric dams on aquatic macroinvertebrate assemblages in two Costa Rican rivers. We measured physicochemical characteristics and sampled aquatic macroinvertebrates from March 2003 to March 2004 in two dammed rivers, Peñas Blancas and San Lorenzo, as well as in the undammed Chachagua River. Sites above and below the dam had differences in their physicochemical variables, with wide variation and extreme values in variables measured below the dam in the San Lorenzo River. Sites below the dams had reduced water discharges, velocities, and depths when compared with sites above the dams, as well as higher temperatures and conductivity. Sites above dams were dominated by collector-gatherer-scrapers and habitat groups dominated by swimmer-clingers, while sites below dams had a more even representation of groups. In contrast, a comparison between two sites at different elevation in the undammed river maintained a similar assemblage composition. Tributaries might facilitate macroinvertebrate recovery above the turbine house, but the assemblage below the turbine house resembled the one below the dam. A massive sediment release event from the dam decreased the abundance per sample and macroinvertebrate taxa below the dam in the Peñas Blancas River. Our study illustrates the effects of hydropower production on neotropical rivers, highlighting the importance of using multiple measures of macroinvertebrate assemblage structure for assessing this type of environmental impact.

Unprocessed real-time imaging of vitreoretinal surgical maneuvers using a microscope-integrated spectral-domain optical coherence tomography system.

PubMed

Hahn, Paul; Migacz, Justin; O'Connell, Rachelle; Izatt, Joseph A; Toth, Cynthia A

2013-01-01

We have recently developed a microscope-integrated spectral-domain optical coherence tomography (MIOCT) device towards intrasurgical cross-sectional imaging of surgical maneuvers. In this report, we explore the capability of MIOCT to acquire real-time video imaging of vitreoretinal surgical maneuvers without post-processing modifications. Standard 3-port vitrectomy was performed in human during scheduled surgery as well as in cadaveric porcine eyes. MIOCT imaging of human subjects was performed in healthy normal volunteers and intraoperatively at a normal pause immediately following surgical manipulations, under an Institutional Review Board-approved protocol, with informed consent from all subjects. Video MIOCT imaging of live surgical manipulations was performed in cadaveric porcine eyes by carefully aligning B-scans with instrument orientation and movement. Inverted imaging was performed by lengthening of the reference arm to a position beyond the choroid. Unprocessed MIOCT imaging was successfully obtained in healthy human volunteers and in human patients undergoing surgery, with visualization of post-surgical changes in unprocessed single B-scans. Real-time, unprocessed MIOCT video imaging was successfully obtained in cadaveric porcine eyes during brushing of the retina with the Tano scraper, peeling of superficial retinal tissue with intraocular forceps, and separation of the posterior hyaloid face. Real-time inverted imaging enabled imaging without complex conjugate artifacts. MIOCT is capable of unprocessed imaging of the macula in human patients undergoing surgery and of unprocessed, real-time, video imaging of surgical maneuvers in model eyes. These capabilities represent an important step towards development of MIOCT for efficient, real-time imaging of manipulations during human surgery.

Multi-trophic resilience of boreal lake ecosystems to forest fires

USGS Publications Warehouse

Lewis, Tyler L.; Lindberg, Mark S.; Schmutz, Joel A.; Bertram, M.R.

2014-01-01

Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before-after-control-impact (BACI) design, with pre- and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire-mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change.

Insect Residue Contamination on Wing Leading Edge Surfaces: A Materials Investigation for Mitigation

NASA Technical Reports Server (NTRS)

Lorenzi, Tyler M.; Wohl, Christopher J.; Penner, Ronald K.; Smith, Joseph G.; Siochi, Emilie J.

2011-01-01

Flight tests have shown that residue from insect strikes on aircraft wing leading edge surfaces may induce localized transition of laminar to turbulent flow. The highest density of insect populations have been observed between ground level and 153 m during light winds (2.6 -- 5.1 m/s), high humidity, and temperatures from 21 -- 29 C. At a critical residue height, dependent on the airfoil and Reynolds number, boundary layer transition from laminar to turbulent results in increased drag and fuel consumption. Although this represents a minimal increase in fuel burn for conventional transport aircraft, future aircraft designs will rely on maintaining laminar flow across a larger portion of wing surfaces to reduce fuel burn during cruise. Thus, insect residue adhesion mitigation is most critical during takeoff and initial climb to maintain laminar flow in fuel-efficient aircraft configurations. Several exterior treatments investigated to mitigate insect residue buildup (e.g., paper, scrapers, surfactants, flexible surfaces) have shown potential; however, implementation has proven to be impractical. Current research is focused on evaluation of wing leading edge surface coatings that may reduce insect residue adhesion. Initial work under NASA's Environmentally Responsible Aviation Program focused on evaluation of several commercially available products (commercial off-the-shelf, COTS), polymers, and substituted alkoxy silanes that were applied to aluminum (Al) substrates. Surface energies of these coatings were determined from contact angle data and were correlated to residual insect excrescence on coated aluminum substrates using a custom-built "bug gun." Quantification of insect excrescence surface coverage was evaluated by a series of digital photographic image processing techniques.

Analysis of silicones released from household items and baby articles by direct analysis in real time-mass spectrometry.

PubMed

Gross, Jürgen H

2015-03-01

Direct analysis in real time-mass spectrometry (DART-MS) enables screening of articles of daily use made of polydimethylsiloxanes (PDMS), commonly known as silicone rubber, to assess their tendency to release low molecular weight silicone oligomers. DART-MS analyses were performed on a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. Flexible silicone baking molds, a watch band, and a dough scraper, as baby articles different brands of pacifiers, nipples, and a teething ring have been examined. While somewhat arbitrarily chosen, the set can be regarded as representative of household items, baby articles, and other objects made of silicone rubber. For comparison, two brands of silicone septa and as blanks a glass slide and a latex pacifier were included. Differences between the objects were mainly observed in terms of molecular weight distribution and occasional release of other compounds in addition to PDMS. Other than that, all objects made of silicone rubber released significant amounts of PDMS during DART analysis. To provide a coarse quantification, a calibration based on silicone oil was established, which delivered PDMS losses from 20 μg to >100 μg during the 16-s period per measurement. Also, the extraction of baking molds in rapeseed oil demonstrated a PDMS release at the level of 1 μg mg(-1). These findings indicate a potential health hazard from frequent or long-term use of such items. This work does not intend to blame certain brands of such articles. Nonetheless, a higher level of awareness of this source of daily silicone intake is suggested.

Multi-trophic resilience of boreal lake ecosystems to forest fires.

PubMed

Lewis, Tyler L; Lindberg, Mark S; Schmutz, Joel A; Bertram, Mark R

2014-05-01

Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before-after-control-impact (BACI) design, with pre- and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll a levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire-mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change.

Associations Between Macroinvertebrates and Paralemanea mexicana, an Endemic Freshwater Red Alga from a Mountain River in Central Mexico.

PubMed

Caro-Borrero, A; Carmona-Jiménez, J

2016-12-01

Macrophytes are common inhabitants of lotic environments and, depending on their morphological traits, possess adaptations that provide shelter to aquatic invertebrates against strong river flow and predators. They may also be used as a food source by macroinvertebrates. The main goal of this study was to determine the relationship between the red alga Paralemanea mexicana and its role as a shelter and/or food source for lotic macroinvertebrates. We also conducted research on the role of microhabitat and morphological variations of the alga in determining macroinvertebrate taxon abundance, diversity, and functional group composition in a high-current velocity river. Results showed that changes in cover and morphology of P. mexicana were mostly correlated with river current velocity, irradiance, and seasonal variation. In turn, these were related to changes in abundance and diversity of the associated macroinvertebrate community. In addition, six macroinvertebrate functional feeding groups were evaluated for associations with the red alga: filtering and gathering collectors, piercers, scrapers, herbivore shredders, and predators. The results showed that the Trichoptera Hydroptilidae genera Ochrotrichia and Metrichia use P. mexicana as a food source and case-building material. The Trichoptera Glossosomatidae Mortoniella uses the alga as a substrate. The biotic interactions between P. mexicana and associated macroinvertebrates reveal the importance of macrophytes as purveyors of substrate, as food and shelter for macroinvertebrates, and also as promoters of macroinvertebrate community diversity. In addition, it was shown that macroinvertebrate herbivory likely facilitates vegetative propagation of the red alga through increased release and germination of carpospores and new gametophytes.

Minesoil grading and ripping affect black walnut growth and survival

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

Josiah, S.J.

In 1980 and 1981, the Botany Department of Southern Illinois University and Sahara Coal Company, Inc. of Harrisburg, Illinois established a series of experimental tree plantings, including black walnut, on a variety of minesoils to explore the effects of different intensities of grading on tree growth. Subsequent walnut stem and root growth were examined during 1985 on five different mine sites: unmined former agricultural land, graded minespoil, replaced (with pan scrapers) topsoil over graded spoil, ripped-graded spoil, and ungraded spoil. Soil bulk density, resistance to penetration, and spoil/soil fertility levels were also measured. The most vigorous trees were found onmore » sites having the lowest soil bulk density and soil strength and lacking horizontal barriers to root growth - the ungraded and ripped sites. Topsoiled sites had the poorest growth and survival, and the greatest stem dieback of any site measured, probably attributable to the confinement of root growth to the upper 15 cm of friable soil above the severely compacted zone. The overall results indicate that most of the minesoil construction techniques examined in this study, which are representative of techniques commonly used in the midwestern US, cause severe minesoil compaction and do not create the proper soil conditions necessary for the survival and vigorous growth of black walnut. Ripping compacted spoil in this and other studies proved to be very effective in alleviating the negative impacts of minesoil compaction. When planning surface mine reclamation activities, ripping should be considered as a possible ameliorative technique when compaction of mined lands is unavoidable and trees are the desired vegetative cover. 4 figures.« less

High-quality cell block preparation from scraping of conventional cytology slide: a technical report on a modified cytoscrape cell block technique.

PubMed

Choi, Y I; Jakhongir, M; Choi, S J; Kim, L; Park, I S; Han, J Y; Kim, J M; Chu, Y C

2016-12-01

Immunocytochemistry (ICC) on formalin-fixed paraffin embedded cell blocks is an ancillary tool commonly recruited for differential diagnoses of fine needle aspiration cytology (FNAC) samples. However, the quality of conventional cell blocks in terms of adequate cellularity and evenness of distribution of cytologic material is not always satisfactory for ICC. We introduce a modified agarose-based cytoscrape cell block (CCB) technique that can be effectively used for the preparation of cell blocks from scrapings of conventional FNAC slides. A decoverslipped FNAC slide was mounted with a small amount of water. The cytological material was scraped off the slide into a tissue mold by scraping with a cell scraper. The cytoscrape material was pelleted by centrifugation and pre-embedded in ultra-low gelling temperature agarose and then re-embedded in conventional agarose. The final agarose gel disk was processed and embedded in paraffin. The quality of the ICC on the CCB sections was identical to that of the immunohistochemical stains on histological sections. By scrapping and harvesting the entirety of the cytological material off the cytology slide into a compact agarose cell button, we could avoid the risk of losing diagnostic material during the CCB preparation. This modified CCB technique enables concentration and focusing of minute material while maintaining the entire amount of the cytoscrape material on the viewing spot of the CCB sections. We believe this technique can be effectively used to improve the level of confidence in diagnosis of FNAC especially when the FNAC slides are the only sample available.

Wetland macroinvertebrates of Prentiss Bay, Lake Huron, Michigan: diversity and functional group composition

USGS Publications Warehouse

Merritt, R.W.; Benbow, M.E.; Hudson, P.L.

2002-01-01

The Great Lakes support many fish and waterbirds that depend directly or indirectly on coastal wetlands during some portion of their life cycle. It is known that macroinvertebrates make up an important part of wetland food webs and ecosystem function; however, our understanding of species distribution within and among wetlands has only recently received attention. We investigated the macroinvertebrates of a freshwater marsh (Prentiss Bay) in the Les Chenaux Island Area of Northern Lake Huron, Michigan. Macroinvertebrate taxa diversity and functional feeding group composition were compared between two habitats. A shallow depositional habitat with higher vegetation diversity and little wave action was compared to a deeper erosional habitat with fewer plant species and more wave action. A total of 83 taxa were collected over the summer of 1996, representing two phyla (Arthropoda and Mollusca) and five classes (Arachnida, Bivalvia, Malacostraca, Gastropoda and Insecta). A total of 79 genera were identified, with 92% being insects (39 families composed of at least 73 genera). Of the total, 42 insect genera were common to both habitats,while relatively fewer were collected exclusively from the erosional compared the depositional habitat. When habitats were pooled, predators comprised about 50% of the functional group taxa, while gathering collectors and shredders each were about 20%. Filtering collectors and scrapers each represented < 10%. When comparing habitats, there was a relatively higher percentage of predators and shredders in the depositional habitat, while all other functional groups were lower. These data suggest that vegetation diversity, depth and wave action affect taxa composition and functional group organization of the Prentiss Bay marsh.

Novel Epoxy Particulate Composites for Mitigation of Insect Residue Adhesion on Future Aircraft Surfaces

NASA Technical Reports Server (NTRS)

Wohl, Christopher J.; Smith, Joseph G., Jr.; Gardner, John M.; Penner, Ronald K.; Connell, John W.; Siochi, Emilie J.

2014-01-01

Drag is reduced significantly for airflow over surfaces when laminar flow can be maintained over greater chord lengths, the distance from the leading edge of an airfoil.1 However, surface imperfections, such as chipped paint, scratches, and events that change topography on a microscopic scale can introduce airflow instabilities resulting in premature transition to turbulent flow.1 Although many of these surface imperfections can be avoided with proper maintenance, advanced materials, and advanced manufacturing practices, topographical surface anomalies arising during flight from insect impacts cannot be controlled and can influence laminar flow stability. Practical solutions to this operational challenge need to be developed for future aircraft to have full advantage of laminar flow designs that improve fuel efficiency.2 Researchers have investigated various methods to mitigate insect residue adhesion for decades.3 Although several techniques have demonstrated efficacy including mechanical scrapers, active liquid discharge systems, and sacrificial paper coatings, they have not been commercially implemented due to increased manufacturing and operational complexity, environmental impact, and weight penalties. Coatings offer a simple route for passive insect residue adhesion prevention without many of the challenges associated with maintenance of laminar flow.4 In our previous work, we determined that most commercially available materials were not effective at insect residue adhesion.5 We also identified improvements when both surface energy could be controlled by surface modifying agents and the topography could be altered through the use of micron-sized and nanometer-sized filler materials.6 In this work, these general principles were applied to an epoxy system to evaluate the behavior of the surface modifying agent, a fluorinated alkyl ether oligomer, on surface energy and insect residue adhesion properties.

A comparison of free-stall barns used by modernized Wisconsin dairies.

PubMed

Bewley, J; Palmer, R W; Jackson-Smith, D B

2001-02-01

A primary objective of the Wisconsin Dairy Modernization Survey was to compare features of free-stall barns available to dairy producers. This study used data from a large random sample of expanding dairy farms to determine whether the theoretical benefits of particular free-stall configurations bear out under on-farm conditions. Comparisons were made among herds using free-stall barns as their primary housing for new versus remodeled facilities, barn design, bedding used, feed-delivery design, manure removal strategies, animal restraint, maternity areas, overcrowding, and cooling methods. Producers who made the transition from tie-stall housing to free-stall housing were satisfied with this decision. New free-stall barns provided a more desirable environment for the herds than remodeled free-stall barns, although initial investments were higher. When new free-stall barns were compared, herds with four-row barns had higher production, lower somatic cell count, and higher stocking rates than herds with six-row barns. Respondents were more satisfied with four- and six-row barns than with two- and three-row barns. Respondents felt sand provided some advantages for cow comfort, while satisfaction with bedding cost and manure handling was higher with mattresses. Dairy Herd Improvement data showed no difference in milk production or somatic cell count for producers who chose sand or mattress-based free stalls. Respondents were more satisfied with the use of drive-through feeding than other feed-delivery designs. Most producers chose to use tractor scrapers to remove manure; however, producers who used automated systems were more satisfied with manure management. Few differences were observed when comparing self-locking head gates to palpation rails. Overcrowding did not have any adverse affect on production or user satisfaction with feed intake or cow comfort. Using supplemental cooling appeared to facilitate higher production.

Benthic macroinvertebrate community structural and functional group response to cooling water discharge in the Savannah River and a coastal plain tributary

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

Poff, N.L.; Matthews, R.A.

1984-01-01

Benthic macroinvertebrate community structure and functional groups on leaf detritus in a thermal, post-thermal and an undisturbed stream, and in the Savannah River immediately downstream from each stream mouth, were compared over a 7 wk (48d) period from December 1982 to February 1983. Ambient temperatures n the post-thermal and undisturbed streams ranged from 4 to 8 and 4 to 11/sup 0/C, respectively, and from 7 to 12/sup 0/C in the Savannah River. Temperatures in the thermal stream fluctuated irregularly between 7 to 31/sup 0/C and in the river below this stream mouth between 7 to 22/sup 0/C. A total ofmore » 13,993 macroinvertebrates representing at least 51 families and 84 genera was collected. Numbers of organisms and taxa were depressed at the thermal stream site, whereas numbers of both organisms and taxa increased at the river site receiving thermal influence. Chironomids of the subfamily Orthocladiinae comprised 46 to 60% of the fauna at all sites except in the thermal stream, where they comprised 5%. Physa (Gastropoda), Ablabesmyia (Tanypodinae) and Tanytarsus (Chironominae) each contributed over 20% of the fauna at the thermal stream. Cheumatopsyche (Trichoptera) represented 12 to 13% of the riverine fauna at the ambient sites, but 25% at the thermally-perturbed site. Collectors (mostly gatherers) contributed 51 to 75% at all sites except the thermal stream where scrapers dominated with 39%. Filterer relative abundance increased from 16 to 19% at the ambient river sites to 29% at the thermally-perturbed river site, suggesting that suspended carbon transport from the thermal stream occurred and subsidized the macroinvertebrate community in the Savannah River. 48 references, 3 figures, 2 tables.« less

Macroinvertebrate distribution and aquatic ecology in the Ruoergai (Zoige) Wetland, the Yellow River source region

NASA Astrophysics Data System (ADS)

Zhao, Na; Xu, Mengzhen; Li, Zhiwei; Wang, Zhaoyin; Zhou, Hanmi

2017-09-01

The Ruoergai (Zoige) Wetland, the largest plateau peatland in the world, is located in the Yellow River source region. The discharge of the Yellow River increases greatly after flowing through the Ruoergai Wetland. The aquatic ecosystem of the Ruoergai Wetland is crucial to the whole Yellow River basin. The Ruoergai wetland has three main kinds of water bodies: rivers, oxbow lakes, and marsh wetlands. In this study, macroinvertebrates were used as indicators to assess the aquatic ecological status because their assemblage structures indicate long-term changes in environments with high sensitivity. Field investigations were conducted in July, 2012 and in July, 2013. A total of 72 taxa of macroinvertebrates belonging to 35 families and 67 genera were sampled and identified. Insecta was the dominant group in the Ruoergai Basin. The alpha diversity of macroinvertebrates at any single sampling site was low, while the alpha diversity on a basin-wide scale was much higher. Macroinvertebrate assemblages in rivers, oxbow lakes, and marsh wetlands differ markedly. Hydrological connectivity was a primary factor causing the variance of the bio-community. The river channels had the highest alpha diversity of macroinvertebrates, followed by marsh wetlands and oxbow lakes. The density and biomass of Gastropoda, collector filterers, and scrapers increased from rivers to oxbow lakes and then to marsh wetlands. The river ecology was particular in the Ruoergai Wetland with the high beta diversity of macroinvertebrates, the low alpha diversity of macroinvertebrates, and the low taxa richness, density, and biomass of EPT (Ephemeroptera, Plecoptera, Trichoptera). To maintain high alpha diversity of macroinvertebrates macroinvertebrates in the Ruoergai Wetland, moderate connectivity of oxbow lakes and marsh wetlands with rivers and measures to control headwater erosion are both crucial.

Shape Variation in Aterian Tanged Tools and the Origins of Projectile Technology: A Morphometric Perspective on Stone Tool Function

PubMed Central

Iovita, Radu

2011-01-01

Background Recent findings suggest that the North African Middle Stone Age technocomplex known as the Aterian is both much older than previously assumed, and certainly associated with fossils exhibiting anatomically modern human morphology and behavior. The Aterian is defined by the presence of ‘tanged’ or ‘stemmed’ tools, which have been widely assumed to be among the earliest projectile weapon tips. The present study systematically investigates morphological variation in a large sample of Aterian tools to test the hypothesis that these tools were hafted and/or used as projectile weapons. Methodology/Principal Findings Both classical morphometrics and Elliptical Fourier Analysis of tool outlines are used to show that the shape variation in the sample exhibits size-dependent patterns consistent with a reduction of the tools from the tip down, with the tang remaining intact. Additionally, the process of reduction led to increasing side-to-side asymmetries as the tools got smaller. Finally, a comparison of shape-change trajectories between Aterian tools and Late Paleolithic arrowheads from the North German site of Stellmoor reveal significant differences in terms of the amount and location of the variation. Conclusions/Significance The patterns of size-dependent shape variation strongly support the functional hypothesis of Aterian tools as hafted knives or scrapers with alternating active edges, rather than as weapon tips. Nevertheless, the same morphological patterns are interpreted as one of the earliest evidences for a hafting modification, and for the successful combination of different raw materials (haft and stone tip) into one implement, in itself an important achievement in the evolution of hominin technologies. PMID:22216161

Seasonal persistence of marine-derived nutrients in south-central Alaskan salmon streams

USGS Publications Warehouse

Rinella, Daniel J.; Wipfi, Mark S.; Walker, Coowe M.; Stricker, Craig A.; Heintz, Ron A.

2013-01-01

Spawning salmon deliver annual pulses of marine-derived nutrients (MDN) to riverine ecosystems around the Pacific Rim, leading to increased growth and condition in aquatic and riparian biota. The influence of pulsed resources may last for extended periods of time when recipient food webs have effective storage mechanisms, yet few studies have tracked the seasonal persistence of MDN. With this as our goal, we sampled stream water chemistry and selected stream and riparian biota spring through fall at 18 stations (in six watersheds) that vary widely in spawner abundance and at nine stations (in three watersheds) where salmon runs were blocked by waterfalls. We then developed regression models that related dissolved nutrient concentrations and biochemical measures of MDN assimilation to localized spawner density across these 27 stations. Stream water ammonium-N and orthophosphate-P concentrations increased with spawner density during the summer salmon runs, but responses did not persist into the following fall. The effect of spawner density on δ15N in generalist macroinvertebrates and three independent MDN metrics (δ15N, δ34S, and ω3:ω6 fatty acids) in juvenile Dolly Varden (Salvelinus malma) was positive and similar during each season, indicating that MDN levels in biota increased with spawner abundance and were maintained for at least nine months after inputs. Delta 15N in a riparian plant, horsetail (Equisetum fluviatile), and scraper macroinvertebrates did not vary with spawner density in any season, suggesting a lack of MDN assimilation by these lower trophic levels. Our results demonstrate the ready assimilation of MDN by generalist consumers and the persistence of this pulsed subsidy in these organisms through the winter and into the next growing season.

Aquatic insect community structure under the influence of small dams in a stream of the Mogi-Guaçu river basin, state of São Paulo.

PubMed

Saulino, H H L; Corbi, J J; Trivinho-Strixino, S

2014-02-01

The fragmentation of lotic systems caused by construction of dams has modified many aquatic communities. The objective of this study was to analyse changes in the aquatic insect community structure by discontinuity of habitat created by dams along the Ribeirão das Anhumas, a sub-basin of the Mogi-Guaçu River (state of São Paulo, Brazil). Entomofauna collection was carried out in 10 segments upstream and downstream of five dams along the longitudinal profile of the stream, with a quick sampling method using a D net (mesh 250 mm) with 2 minutes of sampling effort. The insects were sorted and identified to the lowest possible taxonomic level and analysed by the Shannon diversity index, β diversity, richness estimated by rarefaction curves and relative participation of functional feeding groups. The results showed a slight reduction in diversity in the downstream segments, as well as along the longitudinal profile of the stream. However, there were no significant differences in abundance and richness between the upstream and downstream segments, indicating that the dams did not influence these variables. Differences were observed in the functional feeding groups along the longitudinal profile. Predator and gatherer insects were dominant in all segments analysed. The feeding group of shredders was more abundant in the segment DSIII with the participation of Marilia Müller (Odontoceridae - Trichoptera), although we observed a decrease of shredders and scrapers with the decrease of the canopy cover reducing values of β diversity in the continuum of Ribeirão das Anhumas. This result demonstrated the importance of the conservation of the riparian vegetation in order to maintain the integrity of the stream.

Effects of dietary esfenvalerate exposures on three aquatic insect species representing different functional feeding groups.

PubMed

Palmquist, Katherine R; Jenkins, Jeffrey J; Jepson, Paul C

2008-08-01

Given the chemical properties of synthetic pyrethroids, it is probable that compounds, including esfenvalerate, that enter surface waters may become incorporated into aquatic insect food sources. We examined the effect of dietary esfenvalerate uptake in aquatic insects representing different functional feeding groups. We used three field-collected aquatic insect species: A grazing scraper, Cinygmula reticulata McDunnough (Ephemeroptera: Heptageniidae); an omnivorous filter feeder, Brachycentrus americanus Banks (Trichoptera: Brachycentridae); and a predator, Hesperoperla pacifica Banks (Plecoptera: Perlidae). Laboratory-cultured algae were preexposed for 24 h to esfenvalerate concentrations of 0, 0.025, 0.05, and 0.1 microg/L and provided to two C. reticulata age classes (small and final-instar nymphs). Reduction in small nymph growth was observed following three weeks of feeding on algae exposed to 0.05 and 0.1 microg/L of esfenvalerate, and the highest dietary exposure reduced egg production in final-instar nymphs. The diet for B. americanus and H. pacifica consisted of dead third-instar Chironomus tentans larvae preexposed for 24 h to esfenvalerate concentrations ranging between 0.1 and 1.0 microg/L. Consumption of larvae exposed to 0.5 to 1.0 microg/L of esfenvalerate caused case abandonment and mortality in B. americanus caddisfly larvae. Although H. pacifica nymphs readily consumed esfenvalerate-exposed larvae, no adverse effects were observed during the present study. Furthermore, no evidence of esfenvalerate-induced feeding deterrence was found in any of the species tested, suggesting that aquatic insects may not be able to distinguish between pyrethroid-contaminated and uncontaminated food sources. These findings indicate that feeding deterrence is not a factor in regulating aquatic insect dietary exposures to synthetic pyrethroids.

Towards stressor-specific macroinvertebrate indices: Which traits and taxonomic groups are associated with vulnerable and tolerant taxa?

PubMed

Berger, Elisabeth; Haase, Peter; Schäfer, Ralf B; Sundermann, Andrea

2018-04-01

Monitoring of macroinvertebrate communities is frequently used to define the ecological health status of rivers. Ideally, biomonitoring should also give an indication on the major stressors acting on the macroinvertebrate communities supporting the selection of appropriate management measures. However, most indices are affected by more than one stressor. Biological traits (e.g. size, generation time, reproduction) could potentially lead to more stressor-specific indices. However, such an approach has rarely been tested. In this study we classify 324 macroinvertebrate taxa as vulnerable (decreasing abundances) or tolerant (increasing abundances) along 21 environmental gradients (i.e. nutrients, major ions, oxygen and micropollutants) from 422 monitoring sites in Germany using Threshold Indicator Taxa Analysis (TITAN). Subsequently, we investigate which biological traits and taxonomic groups are associated with taxa classified as vulnerable or tolerant with regard to specific gradients. The response of most taxa towards different gradients was similar and especially high for correlated gradients. Traits associated with vulnerable taxa across most gradients included: larval aquatic life stages, isolated cemented eggs, reproductive cycle per year <1, scrapers, aerial and aquatic active dispersal and plastron respiration. Traits associated with tolerant taxa included: adult aquatic life stages, polyvoltinism, ovoviviparity or egg clutches in vegetation, food preference for dead animals or living microinvertebrates, substrate preference for macrophytes, microphytes, silt or mud and a body size >2-4cm. Our results question whether stressor-specific indices based on macroinvertebrate assemblages can be achieved using single traits, because we observed that similar taxa responded to different gradients and also similar traits were associated with vulnerable and tolerant taxa across a variety of water quality gradients. Future studies should examine whether combinations of traits focusing on specific taxonomic groups achieve higher stressor specificity. Copyright © 2017 Elsevier B.V. All rights reserved.

Macroscopic analysis of gas-jet wiping: Numerical simulation and experimental approach

NASA Astrophysics Data System (ADS)

Lacanette, Delphine; Gosset, Anne; Vincent, Stéphane; Buchlin, Jean-Marie; Arquis, Éric

2006-04-01

Coating techniques are frequently used in industrial processes such as paper manufacturing, wire sleeving, and in the iron and steel industry. Depending on the application considered, the thickness of the resulting substrate is controlled by mechanical (scraper), electromagnetic (if the entrained fluid is appropriated), or hydrodynamic (gas-jet wiping) operations. This paper deals with the latter process, referred to as gas-jet wiping, in which a turbulent slot jet is used to wipe the coating film dragged by a moving substrate. This mechanism relies on the gas-jet-liquid film interaction taking place on the moving surface. The aim of this study is to compare the results obtained by a lubrication one-dimensional model, numerical volume of fluid-large eddy simulation (VOF-LES) modeling and an experimental approach. The investigation emphasizes the effect of the controlling wiping parameters, i.e., the pressure gradient and shear stress distributions induced by the jet, on the shape of the liquid film. Those profiles obtained experimentally and numerically for a jet impinging on a dry fixed surface are compared. The effect of the substrate motion and the presence of the dragged liquid film on these actuators are analyzed through numerical simulations. Good agreement is found between the film thickness profile in the wiping zone obtained from the VOF-LES simulations and with the analytical model, provided that a good model for the wiping actuators is used. The effect of the gas-jet nozzle to substrate standoff distance on the final coating thickness is analyzed; the experimental and predicted values are compared for a wide set of conditions. Finally, the occurrence of the splashing phenomenon, which is characterized by the ejection of droplets from the runback film flow at jet impingement, thus limiting the wiping process, is investigated through experiments and numerical simulations.

Calculation of the transverse kicks generated by the bends of a hollow electron lens

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

Stancari, Giulio

2014-03-25

Electron lenses are pulsed, magnetically confined electron beams whose current-density profile is shaped to obtain the desired effect on the circulating beam in high-energy accelerators. They were used in the Fermilab Tevatron collider for abort-gap clearing, beam-beam compensation, and halo scraping. A beam-beam compensation scheme based upon electron lenses is currently being implemented in the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. This work is in support of a conceptual design of hollow electron beam scraper for the Large Hadron Collider. It also applies to the implementation of nonlinear integrable optics with electron lenses in the Integrable Optics Testmore » Accelerator at Fermilab. We consider the axial asymmetries of the electron beam caused by the bends that are used to inject electrons into the interaction region and to extract them. A distribution of electron macroparticles is deposited on a discrete grid enclosed in a conducting pipe. The electrostatic potential and electric fields are calculated using numerical Poisson solvers. The kicks experienced by the circulating beam are estimated by integrating the electric fields over straight trajectories. These kicks are also provided in the form of interpolated analytical symplectic maps for numerical tracking simulations, which are needed to estimate the effects of the electron lens imperfections on proton lifetimes, emittance growth, and dynamic aperture. We outline a general procedure to calculate the magnitude of the transverse proton kicks, which can then be generalized, if needed, to include further refinements such as the space-charge evolution of the electron beam, magnetic fields generated by the electron current, and longitudinal proton dynamics.« less

Declines in predatory fish promote bloom-forming macroalgae.

PubMed

Eriksson, Britas Klemens; Ljunggren, Lars; Sandström, Alfred; Johansson, Gustav; Mattila, Johanna; Rubach, Anja; Råberg, Sonja; Snickars, Martin

2009-12-01

In the Baltic Sea, increased dominance of ephemeral and bloom-forming algae is presently attributed to increased nutrient loads. Simultaneously, coastal predatory fish are in strong decline. Using field data from nine areas covering a 700-km coastline, we examined whether formation of macroalgal blooms could be linked to the composition of the fish community. We then tested whether predator or nutrient availability could explain the field patterns in two small-scale field experiments, by comparing joint effects on algal net production from nutrient enrichment with agricultural fertilizer and exclusion of larger predatory fish with cages. We also manipulated the presence of invertebrate grazers. The abundance of piscivorous fish had a strong negative correlation with the large-scale distribution of bloom-forming macroalgae. Areas with depleted top-predator communities displayed massive increases in their prey, small-bodied fish, and high covers of ephemeral algae. Combining the results from the two experiments showed that excluding larger piscivorous fish: (1) increased the abundance of small-bodied predatory fish; (2) changed the size distribution of the dominating grazers, decreasing the smaller gastropod scrapers; and (3) increased the net production of ephemeral macroalgae. Effects of removing top predators and nutrient enrichment were similar and additive, together increasing the abundance of ephemeral algae many times. Predator effects depended on invertebrate grazers; in the absence of invertebrates there were no significant effects of predator exclusion on algal production. Our results provide strong support for regional declines of larger predatory fish in the Baltic Sea promoting algal production by decreasing invertebrate grazer control. This highlights the importance of trophic interactions for ecosystem responses to eutrophication. The view emerges that to achieve management goals for water quality we need to consider the interplay between top-down and bottom-up processes in future ecosystem management of marine resources.

Macroinvertebrate assemblage recovery following a catastrophic flood and debris flows in an Appalachian mountain stream

USGS Publications Warehouse

Snyder, C.D.; Johnson, Z.B.

2006-01-01

In June 1995, heavy rains caused severe flooding and massive debris flows on the Staunton River, a 3rd-order stream in the Blue Ridge Mountains (Virginia, USA). Scouring caused the loss of the riparian zone and repositioned the stream channel of the lower 2.1 km of the stream. Between 1998 and 2001, we conducted seasonal macroinvertebrate surveys at sites on the Staunton River and on White Oak Canyon Run, a reference stream of similar size and geology that was relatively unaffected by the flood. Our study was designed to determine the extent to which flood-induced changes to the stream channel and riparian habitats caused long-term changes to macroinvertebrate community structure and composition. Sites within the impacted zone of the Staunton River supported diverse stable benthic macroinvertebrate assemblages 3 y after the flood despite dramatic and persistent changes in environmental factors known to be important controls on stream ecosystem function. However, significant differences in total macroinvertebrate density and trophic structure could be attributed to the flood. In autumn, densities of most feeding guilds, including shredders, were higher at impacted-zone sites than at all other sites, suggesting higher overall productivity in the impacted zone. Higher shredder density in the impacted zone was surprising in light of expected decreases in leaf-litter inputs because of removal of riparian forests. In contrast, in spring, we observed density differences in only one feeding guild, scrapers, which showed higher densities at impacted-zone sites than at all other sites. This result conformed to a priori expectations that reduced shading in the impacted zone would lead to increased light and higher instream primary production. We attribute the seasonal differences in trophic structure to the effects of increased temperatures on food quality and to the relationship between the timing of our sampling and the emergence patterns of important taxa. ?? 2006 by The North American Benthological Society.

Pegasus International, Inc. coating removal systems

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

NONE

1998-02-01

The Pegasus Coating Removal System (PCRS) was demonstrated at Florida International University (FIU) where it was being evaluated for efficiency and cost. In conjunction with the FIU testing demonstration, a human factors assessment was conducted to assess the hazards and associated safety and health issues of concern for workers utilizing this technology. The PCRS is a chemical paste that is applied to the surface using a brush, roller, or airless sprayer. After the type of PCRS, thickness, and dwell time have been determined, a laminated backed material is placed on top of the chemical paste to slow down the dryingmore » process and to provide a mechanism to strip-off the chemical. After the dwell time is reached, the chemical substrate can be removed. Scrapers may be used to break-loose the layers as necessary or to break-loose the layers that are not removed when the laminated paper is picked up. Residue may also be cleaned off of the surface with a damp sponge with an agitating motion, absorbent sponges, or a vacuum, as needed. The paint and removal agent is then placed in drums for disposal at a later time. During the assessment sampling was conducted for organic vapors and general observational techniques were conducted for ergonomics. Recommendations for improved worker safety and health during application and removal of the PCRS include: (1) work practices that reflect avoidance of exposure or reducing the risk of exposure; (2) assuring all PPE and equipment are compatible with the chemicals being used; (3) work practices that reduce the worker`s need to walk on the slippery surface caused by the chemical or the use of special anti-slip soles; (4) careful control of overspray (if a spray application is used); and (5) the use of ergonomically designed long-handled tools to apply and remove the chemical (to alleviate some of the ergonomic concerns).« less

Effects of Debris Flows on Stream Ecosystems of the Klamath Mountains, Northern California

NASA Astrophysics Data System (ADS)

Cover, M. R.; Delafuente, J. A.; Resh, V. H.

2006-12-01

We examined the long-term effects of debris flows on channel characteristics and aquatic food webs in steep (0.04-0.06 slope), small (4-6 m wide) streams. A large rain-on-snow storm event in January 1997 resulted in numerous landslides and debris flows throughout many basins in the Klamath Mountains of northern California. Debris floods resulted in extensive impacts throughout entire drainage networks, including mobilization of valley floor deposits and removal of vegetation. Comparing 5 streams scoured by debris flows in 1997 and 5 streams that had not been scoured as recently, we determined that debris-flows decreased channel complexity by reducing alluvial step frequency and large woody debris volumes. Unscoured streams had more diverse riparian vegetation, whereas scoured streams were dominated by dense, even-aged stands of white alder (Alnus rhombiflia). Benthic invertebrate shredders, especially nemourid and peltoperlid stoneflies, were more abundant and diverse in unscoured streams, reflecting the more diverse allochthonous resources. Debris flows resulted in increased variability in canopy cover, depending on degree of alder recolonization. Periphyton biomass was higher in unscoured streams, but primary production was greater in the recently scoured streams, suggesting that invertebrate grazers kept algal assemblages in an early successional state. Glossosomatid caddisflies were predominant scrapers in scoured streams; heptageniid mayflies were abundant in unscoured streams. Rainbow trout (Oncorhynchus mykiss) were of similar abundance in scoured and unscoured streams, but scoured streams were dominated by young-of-the-year fish while older juveniles were more abundant in unscoured streams. Differences in the presence of cold-water (Doroneuria) versus warm-water (Calineuria) perlid stoneflies suggest that debris flows have altered stream temperatures. Debris flows have long-lasting impacts on stream communities, primarily through the cascading effects of removal of riparian vegetation. Because debris flow frequency increases following road construction and timber harvest, the long-term biological effects of debris flows on stream ecosystems, including anadromous fish populations, needs to be considered in forest management decisions.

LOW-ENGINE-FRICTION TECHNOLOGY FOR ADVANCED NATURAL-GAS RECIPROCATING ENGINES

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

Victor W. Wong; Tian Tian; Grant Smedley

2004-09-30

This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston/ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and emissions. An iterative process of simulation, experimentation and analysis, are being followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. To date, a detailed set of piston/ring dynamic and friction models have been developed and applied that illustrated the fundamental relationships between design parameters and friction losses. Various low-friction strategies and ring-design concepts have been explored, and engine experiments have been done on a full-scalemore » Waukesha VGF F18 in-line 6 cylinder power generation engine rated at 370 kW at 1800 rpm. Current accomplishments include designing and testing ring-packs using a subtle top-compression-ring profile (skewed barrel design), lowering the tension of the oil-control ring, employing a negative twist to the scraper ring to control oil consumption. Initial test data indicate that piston ring-pack friction was reduced by 35% by lowering the oil-control ring tension alone, which corresponds to a 1.5% improvement in fuel efficiency. Although small in magnitude, this improvement represents a first step towards anticipated aggregate improvements from other strategies. Other ring-pack design strategies to lower friction have been identified, including reduced axial distance between the top two rings, tilted top-ring groove. Some of these configurations have been tested and some await further evaluation. Colorado State University performed the tests and Waukesha Engine Dresser, Inc. provided technical support. Key elements of the continuing work include optimizing the engine piston design, application of surface and material developments in conjunction with improved lubricant properties, system modeling and analysis, and continued technology demonstration in an actual full-sized reciprocating natural-gas engine.« less

Baseline assessment of fish communities, benthic macroinvertebrate communities, and stream habitat and land use, Big Thicket National Preserve, Texas, 1999-2001

USGS Publications Warehouse

Moring, J. Bruce

2003-01-01

The Big Thicket National Preserve comprises 39,300 hectares in the form of nine preserve units connected by four stream corridor units (with two more corridor units proposed) distributed over the lower Neches and Trinity River Basins of southeastern Texas. Fish and benthic macroinvertebrate data were collected at 15 stream sites (reaches) in the preserve during 1999–2001 for a baseline assessment and a comparison of communities among stream reaches. The fish communities in the preserve were dominated by minnows (family Cyprinidae) and sunfishes (family Centrarchidae). Reaches with smaller channel sizes generally had higher fish species richness than the larger reaches in the Neches River and Pine Island Bayou units of the preserve. Fish communities in geographically adjacent reaches were most similar in overall community structure. The blue sucker, listed by the State as a threatened species, was collected in only one reach—a Neches River reach a few miles downstream from the Steinhagen Lake Dam. Riffle beetles (family Elmidae) and midges (family Chironomidae) dominated the aquatic insect communities at the 14 reaches sampled for aquatic insects in the preserve. The Ephemeroptera, Plecoptera and Trichoptera (EPT) Index, an index sensitive to water-quality degradation, was smallest at the Little Pine Island Bayou near Beaumont reach that is in a State 303(d)-listed stream segment on Little Pine Island Bayou. Trophic structure of the aquatic insect communities is consistent with the river continuum concept with shredder and scraper insect taxa more abundant in reaches with smaller stream channels and filter feeders more abundant in reaches with larger channels. Aquatic insect community metrics were not significantly correlated to any of the stream-habitat or land-use explanatory variables. The percentage of 1990s urban land use in the drainage areas upstream from 12 bioassessment reaches were negatively correlated to the reach structure index, which indicates less stable habitat for aquatic biota.

Recent advances in stellarator optimization

DOE PAGES

Gates, D. A.; Boozer, A. H.; Brown, T.; ...

2017-10-27

Computational optimization has revolutionized the field of stellarator design. To date, optimizations have focused primarily on optimization of neoclassical confinement and ideal MHD stability, although limited optimization of other parameters has also been performed. Here, we outline a select set of new concepts for stellarator optimization that, when taken as a group, present a significant step forward in the stellarator concept. One of the criticisms that has been leveled at existing methods of design is the complexity of the resultant field coils. Recently, a new coil optimization code—COILOPT++, which uses a spline instead of a Fourier representation of the coils,—wasmore » written and included in the STELLOPT suite of codes. The advantage of this method is that it allows the addition of real space constraints on the locations of the coils. The code has been tested by generating coil designs for optimized quasi-axisymmetric stellarator plasma configurations of different aspect ratios. As an initial exercise, a constraint that the windings be vertical was placed on large major radius half of the non-planar coils. Further constraints were also imposed that guaranteed that sector blanket modules could be removed from between the coils, enabling a sector maintenance scheme. Results of this exercise will be presented. New ideas on methods for the optimization of turbulent transport have garnered much attention since these methods have led to design concepts that are calculated to have reduced turbulent heat loss. We have explored possibilities for generating an experimental database to test whether the reduction in transport that is predicted is consistent with experimental observations. Thus, a series of equilibria that can be made in the now latent QUASAR experiment have been identified that will test the predicted transport scalings. Fast particle confinement studies aimed at developing a generalized optimization algorithm are also discussed. A new algorithm developed for the design of the scraper element on W7-X is presented along with ideas for automating the optimization approach.« less

Recent advances in stellarator optimization

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

Gates, D. A.; Boozer, A. H.; Brown, T.

Computational optimization has revolutionized the field of stellarator design. To date, optimizations have focused primarily on optimization of neoclassical confinement and ideal MHD stability, although limited optimization of other parameters has also been performed. Here, we outline a select set of new concepts for stellarator optimization that, when taken as a group, present a significant step forward in the stellarator concept. One of the criticisms that has been leveled at existing methods of design is the complexity of the resultant field coils. Recently, a new coil optimization code—COILOPT++, which uses a spline instead of a Fourier representation of the coils,—wasmore » written and included in the STELLOPT suite of codes. The advantage of this method is that it allows the addition of real space constraints on the locations of the coils. The code has been tested by generating coil designs for optimized quasi-axisymmetric stellarator plasma configurations of different aspect ratios. As an initial exercise, a constraint that the windings be vertical was placed on large major radius half of the non-planar coils. Further constraints were also imposed that guaranteed that sector blanket modules could be removed from between the coils, enabling a sector maintenance scheme. Results of this exercise will be presented. New ideas on methods for the optimization of turbulent transport have garnered much attention since these methods have led to design concepts that are calculated to have reduced turbulent heat loss. We have explored possibilities for generating an experimental database to test whether the reduction in transport that is predicted is consistent with experimental observations. Thus, a series of equilibria that can be made in the now latent QUASAR experiment have been identified that will test the predicted transport scalings. Fast particle confinement studies aimed at developing a generalized optimization algorithm are also discussed. A new algorithm developed for the design of the scraper element on W7-X is presented along with ideas for automating the optimization approach.« less

Worker safety and injury severity analysis of earthmoving equipment accidents.

PubMed

Kazan, Emrah; Usmen, Mumtaz A

2018-06-01

Research on construction worker safety associated with construction equipment has mostly focused on accident type rather than injury severity and the embedded factor relationships. Significant variables and their effects on the degree of injury are examined for earthmoving equipment using data from OSHA. Four types of equipment, backhoe, bulldozer, excavator, and scraper are included in the study. Accidents involving on-foot workers and equipment operators are investigated collectively, as well as separately. Cross tabulation analysis was conducted to establish the associations between selected categorical variables, using degree of injury as a dichotomous dependent variable (fatal vs. nonfatal) and a number of independent variables having different values. Odds ratios were calculated to determine how much a certain variable/factor increases the odds of fatality in an accident, and the odds ratios were ranked to determine the relative impact of a given factor. It was found that twelve variables were significantly associated with injury severity. Rankings based on odds ratios showed that inadequate safety training (2.54), missing equipment protective system (2.38), being a non-union worker (2.26), being an equipment operator (1.93), and being on or around inadequately maintained equipment (1.58) produced higher odds for fatality. A majority of the earthmoving equipment accidents resulted in fatality. Backhoes were the most common equipment involved in accidents and fatalities. Struck-by accidents were the most prevalent and most fatal. Non-OSHA compliant safety training, missing seatbelt, operator not using seatbelt, malfunctioning back-up alarms, and poorly maintained equipment were factors contributing to accidents and fatalities. On-foot workers experienced a higher number of accidents than operators, while fatality odds were higher for the operators. Practical applications: Safety professionals should benefit from our findings in planning and delivering training and providing oversight to workers in earthmoving equipment operations. Copyright © 2018 National Safety Council and Elsevier Ltd. All rights reserved.

Herbivory drives large-scale spatial variation in reef fish trophic interactions

PubMed Central

Longo, Guilherme O; Ferreira, Carlos Eduardo L; Floeter, Sergio R

2014-01-01

Trophic interactions play a critical role in the structure and function of ecosystems. Given the widespread loss of biodiversity due to anthropogenic activities, understanding how trophic interactions respond to natural gradients (e.g., abiotic conditions, species richness) through large-scale comparisons can provide a broader understanding of their importance in changing ecosystems and support informed conservation actions. We explored large-scale variation in reef fish trophic interactions, encompassing tropical and subtropical reefs with different abiotic conditions and trophic structure of reef fish community. Reef fish feeding pressure on the benthos was determined combining bite rates on the substrate and the individual biomass per unit of time and area, using video recordings in three sites between latitudes 17°S and 27°S on the Brazilian Coast. Total feeding pressure decreased 10-fold and the composition of functional groups and species shifted from the northern to the southernmost sites. Both patterns were driven by the decline in the feeding pressure of roving herbivores, particularly scrapers, while the feeding pressure of invertebrate feeders and omnivores remained similar. The differential contribution to the feeding pressure across trophic categories, with roving herbivores being more important in the northernmost and southeastern reefs, determined changes in the intensity and composition of fish feeding pressure on the benthos among sites. It also determined the distribution of trophic interactions across different trophic categories, altering the evenness of interactions. Feeding pressure was more evenly distributed at the southernmost than in the southeastern and northernmost sites, where it was dominated by few herbivores. Species and functional groups that performed higher feeding pressure than predicted by their biomass were identified as critical for their potential to remove benthic biomass. Fishing pressure unlikely drove the large-scale pattern; however, it affected the contribution of some groups on a local scale (e.g., large-bodied parrotfish) highlighting the need to incorporate critical functions into conservation strategies. PMID:25512851

Long-Term Impacts on Macroinvertebrates Downstream of Reclaimed Mountaintop Mining Valley Fills in Central Appalachia

NASA Astrophysics Data System (ADS)

Pond, Gregory J.; Passmore, Margaret E.; Pointon, Nancy D.; Felbinger, John K.; Walker, Craig A.; Krock, Kelly J. G.; Fulton, Jennifer B.; Nash, Whitney L.

2014-10-01

Recent studies have documented adverse effects to biological communities downstream of mountaintop coal mining and valley fills (VF), but few data exist on the longevity of these impacts. We sampled 15 headwater streams with VFs reclaimed 11-33 years prior to 2011 and sampled seven local reference sites that had no VFs. We collected chemical, habitat, and benthic macroinvertebrate data in April 2011; additional chemical samples were collected in September 2011. To assess ecological condition, we compared VF and reference abiotic and biotic data using: (1) ordination to detect multivariate differences, (2) benthic indices (a multimetric index and an observed/expected predictive model) calibrated to state reference conditions to detect impairment, and (3) correlation and regression analysis to detect relationships between biotic and abiotic data. Although VF sites had good instream habitat, nearly 90 % of these streams exhibited biological impairment. VF sites with higher index scores were co-located near unaffected tributaries; we suggest that these tributaries were sources of sensitive taxa as drifting colonists. There were clear losses of expected taxa across most VF sites and two functional feeding groups (% scrapers and %shredders) were significantly altered. Percent VF and forested area were related to biological quality but varied more than individual ions and specific conductance. Within the subset of VF sites, other descriptors (e.g., VF age, site distance from VF, the presence of impoundments, % forest) had no detectable relationships with biological condition. Although these VFs were constructed pursuant to permits and regulatory programs that have as their stated goals that (1) mined land be reclaimed and restored to its original use or a use of higher value, and (2) mining does not cause or contribute to violations of water quality standards, we found sustained ecological damage in headwaters streams draining VFs long after reclamation was completed.

Depth-related response of macroinvertebrates to the reversal of eutrophication in a Mediterranean lake: Implications for ecological assessment.

PubMed

Bazzanti, Marcello; Mastrantuono, Luciana; Pilotto, Francesca

2017-02-01

A better management of nutrient inflows into lakes has led to an improvement in their conditions (i.e. reversal of eutrophication) and the effects of this on macroinvertebrate communities that inhabit different lake-depth zones is largely unknown. This paper reports a comparison of macroinvertebrate communities living in the eulittoral, infralittoral and sublittoral/profundal zones of Lake Nemi (Central Italy) before and after its natural recovery from eutrophication following the deviation of domestic wastewater. The infralittoral zone responded more rapidly than the other two depth-zones to the improved ecological conditions, as shown by larger differences in community composition between the two periods. In the eulittoral sand, the combined effects of hydromorphological pressures and reversal of eutrophication hindered the biotic response. In the eulittoral and infralittoral zones, typical taxa of mesotrophic waters appeared or increased their abundances after the eutrophication reversal. Benthic invertebrate response was slower in the sublittoral/profundal zone due to deoxygenation that continued to prevail in the deepest area of the lake during summer. However, both tolerant and more sensitive taxa were collected there for the first time. After the reversal of eutrophication, the percentage of molluscan+large crustaceans increased in the infralittoral zone, whereas the oligochaete/chironomid ratio decreased in both sublittoral/profundal and infralittoral zones. Functional feeding metrics (percentages of filter-feeders, collector-gatherers, miners and scrapers/grazers) differently tracked the reversal of eutrophication in the three depth-zones probably according to the effects of the reduction of nutrients on food-web structure influencing macroinvertebrates. Biological Monitoring Working Party (BMWP) and the Average Score Per Taxon (ASPT) seemed to respond to eutrophication reversal only in the sublittoral/profundal zone, where deoxygenation plays a major role as a structuring agent of the community. Our results suggest that the effects of reversal of eutrophication can be better assessed by examining the response of the communities belonging to each zone individually. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of sewage effluents and seasonal changes on the metabolism of three Atlantic rivers.

PubMed

Rodríguez-Castillo, Tamara; Barquín, José; Álvarez-Cabria, Mario; Peñas, Francisco J; Álvarez, César

2017-12-01

Sewage inputs on fluvial ecosystems affect benthic communities and alter trophic networks resulting in changes on river functioning. Functional indicators (e.g. river metabolism) have been proposed as a valuable tool to evaluate ecosystem impairment. In the present study we monitored river metabolism in spring (few days after a major flood) and in summer (after 35days of low flow conditions) using both single-station and two-stations methods over a 24h period up and downstream of wastewater treatment plant (WWTP) effluents on three Atlantic river reaches located in northern Spain (Europe). Concurrently with river metabolism, we characterized environmental characteristics (flow, velocity, depth, pH, water temperature, nutrients, etc.), benthic macroinvertebrate communities and biofilm (algae and epilithic biomass). Ecosystem Respiration (ER 24 ) was similar at the different periods and locations, but Gross Primary Productivity (GPP) tended to decrease in impacted reaches (downstream WWTPs) and in summer (except in the Saja River). However, the balance of the metabolic processes showed a trend towards autotrophy in the largest river, while WWTP effluents increased its autotrophy. Chlorophyll a concentration was >4 times larger in spring than in summer in all river reaches, while epilithic biomass followed a similar but less obvious pattern. Increase of invertebrate scraper densities (mainly, Potamopyrgus antipodarum) seems to be a plausible explanation for biofilm biomass temporal patterns in all sites (higher in spring than in summer), altering GPP and ER 24 patterns. Thus, metabolism rates show different responses to WWTP effluents depending on season and on the relationships among functional and structural components, with special focus on the composition and structure of macroinvertebrate communities. Increasing our understanding of cause-effect relationships on the impairment of aquatic ecosystems needs to account for both structural and functional components and their interactions. Copyright © 2017 Elsevier B.V. All rights reserved.

Culturing bone marrow cells with dexamethasone and ascorbic acid improves osteogenic cell sheet structure.

PubMed

Akahane, M; Shimizu, T; Kira, T; Onishi, T; Uchihara, Y; Imamura, T; Tanaka, Y

2016-11-01

To assess the structure and extracellular matrix molecule expression of osteogenic cell sheets created via culture in medium with both dexamethasone (Dex) and ascorbic acid phosphate (AscP) compared either Dex or AscP alone. Osteogenic cell sheets were prepared by culturing rat bone marrow stromal cells in a minimal essential medium (MEM), MEM with AscP, MEM with Dex, and MEM with Dex and AscP (Dex/AscP). The cell number and messenger (m)RNA expression were assessed in vitro, and the appearance of the cell sheets was observed after mechanical retrieval using a scraper. β-tricalcium phosphate (β-TCP) was then wrapped with the cell sheets from the four different groups and subcutaneously implanted into rats. After mechanical retrieval, the osteogenic cell sheets from the MEM, MEM with AscP, and MEM with Dex groups appeared to be fragmented or incomplete structures. The cell sheets cultured with Dex/AscP remained intact after mechanical retrieval, without any identifiable tears. Culture with Dex/AscP increased the mRNA and protein expression of extracellular matrix proteins and cell number compared with those of the other three groups. More bridging bone formation was observed after transplantation of the β-TCP scaffold wrapped with cell sheets cultured with Dex/AscP, than in the other groups. These results suggest that culture with Dex/AscP improves the mechanical integrity of the osteogenic cell sheets, allowing retrieval of the confluent cells in a single cell sheet structure. This method may be beneficial when applied in cases of difficult tissue reconstruction, such as nonunion, bone defects, and osteonecrosis.Cite this article: M. Akahane, T. Shimizu, T. Kira, T. Onishi, Y. Uchihara, T. Imamura, Y. Tanaka. Culturing bone marrow cells with dexamethasone and ascorbic acid improves osteogenic cell sheet structure. Bone Joint Res 2016;5:569-576. DOI: 10.1302/2046-3758.511.BJR-2016-0013.R1. © 2016 Akahane et al.

Influence of Soils, Riparian Zones, and Hydrology on Nutrients, Herbicides, and Biological Relations in Midwestern Agricultural Streams

NASA Astrophysics Data System (ADS)

Porter, S.

2001-12-01

Chemical, biological, and habitat conditions were characterized in 70 streams in the upper Mississippi River basin during August 1997, as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. The study was designed to evaluate algal and macroinvertebrate responses to high agricultural intensity in relation to nonpoint sources of nutrients and herbicides, characteristics of basin soils, wooded-riparian vegetation, and hydrology. Concentrations and forms of nutrients, herbicides and their metabolites, and seston constituents varied significantly with regional differences in soil properties, ground and surface water relations, density of riparian trees, and precedent rainfall-runoff conditions. Dissolved nitrate concentrations were relatively low in streams with high algal productivity; however, nitrate concentrations increased with basin water yield, which was associated with the regional distribution of rainfall during the month prior to the study. Stream productivity and respiration were positively correlated with seston (phytoplankton) chlorophyll concentrations, which were significantly larger in streams in areas with poorly drained soils and low riparian-tree density. Concentrations of dissolved phosphorus were low in streams where periphyton biomass was high. Periphyton biomass was relatively larger in streams with clear water and low abundance of macroinvertebrates that consume algae. Periphyton biomass decreased rapidly with modest increases in the abundance of scrapers such as snails and certain mayfly taxa. Differences in dissolved oxygen, organic carbon, stream velocity, and precedent hydrologic conditions explained much of the variance in macroinvertebrate community structure. The overall number of macroinvertebrate species and number of mayfly, caddisfly, and stonefly (EPT) taxa that are sensitive to organic enrichment were largest in streams with moderate periphyton biomass, in areas with moderately-well drained soils and high riparian-tree density. Regional differences in hydrologic processes can account for significant differences or gradients in chemical and biological conditions in streams that drain a relatively homogeneous landscape.

Modulation of cardiac myocyte phenotype in vitro by the composition and orientation of the extracellular matrix.

PubMed

Simpson, D G; Terracio, L; Terracio, M; Price, R L; Turner, D C; Borg, T K

1994-10-01

Cellular phenotype is the result of a dynamic interaction between a cell's intrinsic genetic program and the morphogenetic signals that serve to modulate the extent to which that program is expressed. In the present study we have examined how morphogenetic information might be stored in the extracellular matrix (ECM) and communicated to the neonatal heart cell (NHC) by the cardiac alpha 1 beta 1 integrin molecule. A thin film of type I collagen (T1C) was prepared with a defined orientation. This was achieved by applying T1C to the peripheral edge of a 100 mm culture dish. The T1C was then drawn across the surface of the dish in a continuous stroke with a sterile cell scraper and allowed to polymerize. When NHCs were cultured on this substrate, they spread, as a population, along a common axis in parallel with the gel lattice and expressed an in vivo-like phenotype. Individual NHCs displayed an elongated, rod-like shape and disclosed parallel arrays of myofibrils. These phenotypic characteristics were maintained for at least 4 weeks in primary culture. The evolution of this tissue-like organizational pattern was dependent upon specific interactions between the NHCs and the collagen-based matrix that were mediated by the cardiac alpha 1 beta 1 integrin complex. This conclusion was supported by a variety of experimental results. Altering the tertiary structure of the matrix or blocking the extracellular domains of either the cardiac alpha 1 or beta 1 integrin chain inhibited the expression of the tissue-like pattern of organization. Neither cell-to-cell contact or contractile function were necessary to induce the formation of the rod-like cell shape. However, beating activity was necessary for the assembly of a well-differentiated myofibrillar apparatus. These data suggest that the cardiac alpha 1 beta 1 integrin complex serves to detect and transduce phenotypic information stored within the tertiary structure of the surrounding matrix.

Subsurface Structure of the Bushveld Igneous Complex, South Africa: An Application of Geophysics

NASA Astrophysics Data System (ADS)

Vallejo, G.; Galindo, B. L.; Carranza, V.; Gomez, C. D.; Ortiz, K.; Castro, J. G.; Falzone, C.; Guandique, J.; Emry, E.; Webb, S. J.; Nyblade, A.

2014-12-01

South Africa is host to the largest single known platinum group metal supply in the world. The Bushveld Igneous Complex, spanning 300x400 kilometers, hosts hundreds of years' worth of platinum, chromite, vanadium, and other ore. Its wealth of these metals is tied directly to the large layered igneous intrusion that formed roughly 2061 million years ago. The extraction of platinum is vital to the industrial world - as these metals are widely used in the automotive industry, dental restorations, computer technology, in addition to many other applications. In collaboration with the Africa Array geophysics field school and the Penn State Summer Research Opportunities Program (SROP), we surveyed the Modikwa mine located along the border of the provinces of Mpumalanga and Limpopo in South Africa. The following techniques were applied to survey the area of interest: seismic refraction and reflection, gravity, magnetics, electrical resistivity, and electromagnetics. The data collected were used to determine the depth to bedrock and to identify potential mining hazards from dykes and faults in the bedrock. Several areas were studied and with the combination of the above-mentioned methods several possible hazards were identified. One broad, major dyke that was located in a prior aeromagnetic survey and several previously undetected, parallel, minor dykes were identified in the region. The overburden thickness was determined to be ̴4-5 meters in some regions, and as thin as several centimeters in others. This section of rock and soil lies above an area where platinum will likely be mined in the future. The removal of overburden can be accomplished by using power shovels or scrapers; while remaining material can be contained with the use of galvanized steel culverts. Additionally, a number of joints were located that may have allowed water to accumulate underground. The models created from the data permit us to estimate which hazards could be present in different parts of the land surveyed. These results are important information that will help determine how deep to mine while also avoiding hazards that could result in serious injuries to personnel or cause costly damages to equipment.

Dynamic Monitoring Reveals Motor Task Characteristics in Prehistoric Technical Gestures

PubMed Central

Pfleging, Johannes; Stücheli, Marius; Iovita, Radu; Buchli, Jonas

2015-01-01

Reconstructing ancient technical gestures associated with simple tool actions is crucial for understanding the co-evolution of the human forelimb and its associated control-related cognitive functions on the one hand, and of the human technological arsenal on the other hand. Although the topic of gesture is an old one in Paleolithic archaeology and in anthropology in general, very few studies have taken advantage of the new technologies from the science of kinematics in order to improve replicative experimental protocols. Recent work in paleoanthropology has shown the potential of monitored replicative experiments to reconstruct tool-use-related motions through the study of fossil bones, but so far comparatively little has been done to examine the dynamics of the tool itself. In this paper, we demonstrate that we can statistically differentiate gestures used in a simple scraping task through dynamic monitoring. Dynamics combines kinematics (position, orientation, and speed) with contact mechanical parameters (force and torque). Taken together, these parameters are important because they play a role in the formation of a visible archaeological signature, use-wear. We present our new affordable, yet precise methodology for measuring the dynamics of a simple hide-scraping task, carried out using a pull-to (PT) and a push-away (PA) gesture. A strain gage force sensor combined with a visual tag tracking system records force, torque, as well as position and orientation of hafted flint stone tools. The set-up allows switching between two tool configurations, one with distal and the other one with perpendicular hafting of the scrapers, to allow for ethnographically plausible reconstructions. The data show statistically significant differences between the two gestures: scraping away from the body (PA) generates higher shearing forces, but requires greater hand torque. Moreover, most benchmarks associated with the PA gesture are more highly variable than in the PT gesture. These results demonstrate that different gestures used in ‘common’ prehistoric tasks can be distinguished quantitatively based on their dynamic parameters. Future research needs to assess our ability to reconstruct these parameters from observed use-wear patterns. PMID:26284785

Characterization of fieldstone for a provenance study of local building stones and artifacts

NASA Astrophysics Data System (ADS)

Goossens, M.; De Kock, T.; Dewanckele, J.; Boone, M.; De Boever, W.; Brabant, L.; Louwye, S.; De Ceukelaire, M.; Vanhaecke, F.; Cnudde, V.

2012-04-01

Fieldstone is a Belgian silicified sandstone speckled with glauconite. The hardness varies with the degree of silicification and its colour, which is usually greenish, can differ from bluish gray to orange depending on the degree of oxidation of the glauconite. Although recently discovered in the clayey interlayers, fieldstone mainly appears in the sandy units of the Eocene in Western Flanders (Belgium). It occurs as lenses and banks parallel to the stratification. From Roman times onwards, these were locally intensely cultivated as local building stones. Furthermore archeological evidence points out fieldstone was used in prehistoric times to make various artifacts like scrapers and jacks. The purpose of our study is to characterize fieldstone from the different known geographical and stratigraphical localities. Ambiguous stratigraphical classifications of fieldstone outcrops in the past have complicated previous studies of fieldstone. Therefore, we aim to provide clarity over its stratigraphical occurrence and deliver additional information about its formation. The ultimate goal is to trace back the origin of the fieldstone used in buildings and for archeological artifacts to a distinct locality. For the characterization of the fieldstone different techniques were used. Thin sections were examined by petrographical microscopy in order to study grain size, porosity, mineralogy, degree of silicification and in some samples microfossil content like silicified foraminifers. Porosity was determined with volumetric analysis and high resolution X-ray computer tomography. Attention towards the dinoflagellate content was given. This can provide information about the age and depositional environment of the silicified sands. In addition, it can act as a distinct feature that is characteristic for one locality or stratigraphic layer. A selected amount of samples were chemically analysed with Laser Ablation Inductively Coupled Plasma Mass Spectrometer in order to check if this could provide a chemical fingerprint which can be used to distinguish fieldstone coming from different localities from each other. By combining all this information we aim at composing an outline to trace back the origin of the fieldstone used as building stone and for artifacts.

The role of burrowing sponges in bioerosion.

PubMed

Rützler, Klaus

1975-09-01

Among the large number of limestone-eroding organisms, sponges, mainly of the family Clinonidae are of special interest because of their efficient means of substratum penetration by cellular etching and because they release characteristically shaped calcium carbonate chips which can be detected in the mud-size fraction of many sediments. Identifiable trace fossils and sediments are of great ecological and paleoecological significance.As new data on the excavating mechanism have become available, the questions of burrowing rates and sediment production have gained importance. Extrapolation from shortterm experiments (under 6 months) on substrate invasion are inconclusive because of high initial penetration rates resulting from mechanical stimulation and lack of competition. New experiments show that the rate curve flattens after 6 months and that optimum longterm erosion of CaCO 3 does not exceed 700 mg m -2 year -1 (Cliona lampa and C. aprica). Substrate limitations and competition will further reduce this rate.By monitoring the production of CaCO 3 chips by Cliona lampa, it was possible to link activity patterns to certain environmental factors. Mechanical stimuli, high light intensity, strong currents and, possibly, low temperature seem to accelerate the burrowing process. Sponge-generated chips can make up over 40% of coral mud when deposited in the current shadow of the reef framework.Using transect counts and sponge area-biomass conversion factors, the mean abundance of burrowing sponges on the Bermuda platform could be calculated. On suitable hard bottom substrates it averages 16 g dry weight per m 2 . From this value the burrowing potential of sponges can be estimated as 256 g CaCO 3 per m 2 substrate per year. Since 97-98% of the eroded limestone remains in particulate form, the contribution of fine sediments can amount to 250 g m -2 year -1 .Attention is called to the fact that erosion rates by burrowers can not directly be compared with those of borers or scrapers. The former are intermittent and their activities are affected by environmental and biological interactions, while activities of the latter are rather constant and guided by the need for food.

Functional feeding groups of aquatic insect families in Latin America: a critical analysis and review of existing literature.

PubMed

Ramírez, Alonso; Gutiérrez-Fonseca, Pablo E

2014-04-01

Aquatic macroinvertebrates are involved in numerous processes within aquatic ecosystems. They often have important effects on ecosystem processes such as primary production (via grazing), detritus breakdown, and nutrient mineralization and downstream spiraling. The functional feeding groups (FFG) classification was developed as a tool to facilitate the incorporation of macroinvertebrates in studies of aquatic ecosystems. This classification has the advantage of combining morphological characteristics (e.g., mouth part specialization) and behavioral mechanisms (e.g., way of feeding) used by macroinvertebrates when consuming resources. Although recent efforts have greatly advanced our ability to identify aquatic macroinvertebrates, there is limited information on FFG assignment. Furthermore, there has been some variation in the use of the FFG classification, in part due to an emphasis on using gut content analysis to assign FFG, which is more appropriate for assigning trophic guilds. Thus, the main goals of this study are to (1) provide an overview of the value of using the FFG classification, (2) make an initial attempt to summarize available information on FFG for aquatic insects in Latin America, and (3) provide general guidelines on how to assign organisms to their FFGs. FFGs are intended to reflect the potential effects of organisms in their ecosystems and the way they consume resources. Groups include scrapers that consume resources that grow attached to the substrate by removing them with their mouth parts; shredders that cut or chew pieces of living or dead plant material, including all plant parts like leaves and wood; collectors-gatherers that use modified mouth parts to sieve or collect small particles (< 1 mm) accumulated on the stream bottom; filterers that have special adaptations to remove particles directly from the water column; and predators that consume other organisms using different strategies to capture them. In addition, we provide details on piercers that feed on vascular plants by cutting or piercing the tissue using sharp or chewing mouth parts and consume plant liquids. We also provide a list of families of aquatic insects in Latin America, with an initial assignment to FFGs. We recommended caution when assigning FFGs based on gut contents, as it can provide misleading information. Overall, FFG is a very useful tool to understand the role of aquatic macroinvertebrates in stream ecosystems and comparisons among studies will benefit from consistency in their use.

Guanaco traces and hunting strategies at Alto Patache North Chilean fog oasis

NASA Astrophysics Data System (ADS)

Larrain, H.; Cereceda, P.; Pérez, L.

2010-07-01

1. In foregoing Fog Conferences, some of us have made explicit the rich botanic and faunistic inventory to be found at this Chilean Fog site. This was specially apparent under strong ENSO conditions, as it happened in 1997/98 in the area. Among the mammal biggest species represented, the guanaco (Lama guanicoe Müller) merits special mention. Clear traces of their presence and eventual hunting and slaughtering by primitive populations have survived until present times. Among them, the myriads of guanaco trails still covering practically all the slopes along the foggy area, close to the sea, and their wollowing and defecating places are found. Also, although less studied, plant eating traces left behind by roaming camelids can be seen. 2. Guanaco hunting traces still visible at Alto Patache can be portrayed differently through : A) Analysis of lithic artifacts used as arms in hunting operations; B) Botanic response to animal attack; C) Examination of topographic traits used by primitive man in guanaco hunting strategies. A. Hundreds of lithic instruments made of stone, were abandoned by hunters in situ, some of them were intact, some fragmented, which would demonstrate a direct relationship with hunting and slaughtering, and also their elaboration in workshops at place. Lithic points, scrapers and knives were found at places specially apt for hunting or slaughtering activities. Total isolation of the mountain fog site previous to our arrival in 1996, favoured their conservation at place. B. Careful observation of some local plants showed clear traces of guanaco feeding habits. As a proof thereof, old cactus of the species Eulychnia iquiquensis show in their basal portions clear signals in the forms of scars, caused by the eating by guanacos. Guanaco faeces were found at the foot of Ephedra plants. Many dead Stipa ichu plants (Gramineae), in different areas of the oasis provide evidence of cutting close to their basis, caused by sharp guanaco tooth under severe food scarcity. C. Special lookouts located at high places offering clear visibility were used by hunters. Some were built up, some others consisted of natural stone arrangements. The same can be said for the wollowing places, located in plains with loose or sandy soils. Pictures showing different artifacts, plants or topographic traits used, will be presented here as evidence of guanaco hunting activity at place.

Hydrological cycle effects on the aquatic community in a Neotropical stream of the Andean piedmont during the 2007-2010 ENSO events.

PubMed

Ríos-Pulgarín, M I; Barletta, M; Mancera-Rodriguez, N J

2016-07-01

The seasonal and interannual changes in the fish, macroinvertebrates and phycoperiphyton assemblages of the Guarinó River were examined in relation to the physical and chemical environmental changes associated with the hydrological cycle and the El Niño-Niña/Southern Oscillation (ENSO) between 2007 and 2010. Four samplings (in dry and rainy seasons) were performed per year. Environmental variables (temperature, pH, conductivity, turbidity, oxygen, total nitrogen, orthophosphate, depth and flow rate) were measured. The temporal patterns of the taxonomic compositions for the three assemblages and the functional composition of fish and macroinvertebrate assemblages with respect to environmental variables were examined through canonical discriminant analysis, multidimensional scaling and multiple correlations. The presence and abundance of fishes, macroinvertebrates and algae species were regulated by environmental variables associated with extreme hydrological events, which derived from the natural torrential regimen of the basin and larger-scale phenomena, such as El Niño and La Niña. Fish abundance and richness were significantly correlated with algal density and pH, the macroinvertebrate density was negatively related to the flow rate and the richness was positively correlated with algal density. The algae richness was positively correlated with pH and negatively correlated with the flow rate and nitrogen. The algal density was positively correlated with pH and temperature and negatively correlated with river flow. The phycoperiphyton assemblage exhibited more direct responses in its density and richness to the hydrological changes (r(2) = 0·743 and 0·800, respectively). In functional terms, the El Niño phenomenon was defined by a greater abundance of omnivorous and insectivorous fishes, as well as filter feeders, scrapers and macroinvertebrate predators. During La Niña, a greater abundance of benthic fishes (both detritivorous and insectivorous) and shredder and collector-gatherer macroinvertebrates was observed. Differentiated responses recorded in the community were based on adaptive strategies for the local hydrological regime that enable fast recovery under conditions such as ENSO phenomena. Composition changes according to adaptations to different hydrological scenarios and the predominance of generalists' trophic guilds and species with plasticity in their habits and their ranges of environmental tolerance were found, supporting the habitat templet model. © 2016 The Fisheries Society of the British Isles.

[Spatial patterns in communities of aquatic macroinvertebrates of Argentinean Puna].

PubMed

Nieto, Carolina; Malizia, Agustina; Carilla, Julieta; Izquierdo, Andrea; Rodríguez, José; Cuello, Soledad; Zannier, Martín; Grau, H Ricardo

2016-06-01

Spatial patterns in communities of aquatic macroinvertebrates of Argentinean Puna. The macroinvertebrates are a vital component of freshwater ecosystems as they contribute to the process of organic matter while serving as food for other organisms such as fish and amphibians. Unfortunately, the knowledge of the aquatic diversity is poor in the high Andean systems (between 3 200 and 5 200 m.a.s.l. and rainfall below 300 mm per year), especially in the Argentinean peatbogs, a fact which has made difficult the interpretation of spatial patterns on a regional scale. The present study aimed to describe the composition of aquatic macroinvertebrates in seven peatbogs in the Argentinean Puna, and to analyze for the first time their spatial patterns. For this, we studied the relationship of these organisms with the environment, and obtained information about the surrounding vegetation and water physico-chemical characteristics. A total of 3 131 specimens of aquatic macroinvertebrates were collected, representing 25 taxa belonging to 22 families and 24 genera. In addition, 62 species of vascular plants were recorded, belonging to 20 families. The most abundant life form were the tufted grasses, followed by cushions. By using an NMDS (Non-Metrical Multidimensional Scaling) statistical analysis, the sampling sites were ordered in each peatbog as follows. The peatbogs located furthest West and South with higher water temperature were grouped on axis 1, whereas those with higher conductivity, whole water dissolved solids and salt concentration were grouped on axis 2. The water temperature was higher than air temperature at all times, and we found no association between temperature and altitude. The altitude had no correlation with the abundance of macroinvertebrates or with plant richness. Life forms such as scattered graminoids, trailing and prostrate herbs (in many cases they get into the channel) and aquatic plants were more abundant in peatbogs 4, 5 and 7 and they had a correlation with some macroinvertebrates belonging to functional trophic groups such as filter-collectors, collectors and scrapers. Finally, conductivity, whole dissolved solids and salt concentration had their highest value in peatbog 6, where Bivalvia (filter-collector) and Hyalella (collector) were also found. The results obtained attest that these macroinvertebrates displayed diversity and composition spatial patterns, the most important feature being their relationship with the surrounding vegetation, and to a lesser extent, with the physical and chemical traits of water in seven fertile lowlands in the Argentinean Puna.

Influence of dietary carbon on mercury bioaccumulation in streams of the Adirondack Mountains of New York and the Coastal Plain of South Carolina, USA

USGS Publications Warehouse

Riva-Murray, Karen; Bradley, Paul M.; Chasar, Lia C.; Button, Daniel T.; Brigham, Mark E.; Eikenberry, Barbara C. Scudder; Journey, Celeste A.; Lutz, Michelle A.

2013-01-01

We studied lower food webs in streams of two mercury-sensitive regions to determine whether variations in consumer foraging strategy and resultant dietary carbon signatures accounted for observed within-site and among-site variations in consumer mercury concentration. We collected macroinvertebrates (primary consumers and predators) and selected forage fishes from three sites in the Adirondack Mountains of New York, and three sites in the Coastal Plain of South Carolina, for analysis of mercury (Hg) and stable isotopes of carbon (δ13C) and nitrogen (δ15N). Among primary consumers, scrapers and filterers had higher MeHg and more depleted δ13C than shredders from the same site. Variation in δ13C accounted for up to 34 % of within-site variation in MeHg among primary consumers, beyond that explained by δ15N, an indicator of trophic position. Consumer δ13C accounted for 10 % of the variation in Hg among predatory macroinvertebrates and forage fishes across these six sites, after accounting for environmental aqueous methylmercury (MeHg, 5 % of variation) and base-N adjusted consumer trophic position (Δδ15N, 22 % of variation). The δ13C spatial pattern within consumer taxa groups corresponded to differences in benthic habitat shading among sites. Consumers from relatively more-shaded sites had more enriched δ13C that was more similar to typical detrital δ13C, while those from the relatively more-open sites had more depleted δ13C. Although we could not clearly attribute these differences strictly to differences in assimilation of carbon from terrestrial or in-channel sources, greater potential for benthic primary production at more open sites might play a role. We found significant variation among consumers within and among sites in carbon source; this may be related to within-site differences in diet and foraging habitat, and to among-site differences in environmental conditions that influence primary production. These observations suggest that different foraging strategies and habitats influence MeHg bioaccumulation in streams, even at relatively small spatial scales. Such influence must be considered when selecting lower trophic level consumers as sentinels of MeHg bioaccumulation for comparison within and among sites.

Bone regeneration with osteogenic matrix cell sheet and tricalcium phosphate: An experimental study in sheep.

PubMed

Kira, Tsutomu; Akahane, Manabu; Omokawa, Shohei; Shimizu, Takamasa; Kawate, Kenji; Onishi, Tadanobu; Tanaka, Yasuhito

2017-10-18

To determine the effects of a cell sheet created from sheep bone marrow and tricalcium phosphate (TCP) on osteogenesis. Bone marrow cells were harvested from a sheep and cultured in a minimal essential medium (MEM) containing ascorbic acid phosphate (AscP) and dexamethasone (Dex). After 2 wk, the formed osteogenic matrix cell sheet was lifted from the culture dish using a scraper. Additionally, harvested bone marrow cells were cultured in MEM only as a negative control group, and in MEM with AscP, Dex, and β-glycerophosphate as a positive control group. For in vitro evaluation, we measured the alkaline phosphatase (ALP) activity and osteocalcin (OC) content in the media of the cultured cells from each group. For in vivo analysis, a porous TCP ceramic was used as a scaffold. We prepared an experimental group comprising TCP scaffolds wrapped with the osteogenic matrix cell sheets and a control group consisting of the TCP scaffold only. The constructs were implanted subcutaneously into athymic rats and the cell donor sheep, and bone formation was confirmed by histology after 4 wk. In the in vitro part, the mean ALP activity was 0.39 ± 0.03 mg/well in the negative control group, 0.67 ± 0.04 mg/well in the sheet group, and 0.65 ± 0.07 mg/well in the positive control group. The mean OC levels were 1.46 ± 0.33 ng/well in the negative control group, 3.92 ± 0.16 ng/well in the sheet group, and 4.4 ± 0.47 ng/well in the positive control group, respectively. The ALP activity and OC levels were significantly higher in the cell sheet and positive control groups than in the negative control group ( P < 0.05). There was no significant difference in ALP activity or OC levels between the cell sheet group and the positive control group ( P > 0.05). TCP constructs wrapped with cell sheets prior to implantation showed bone formation, in contrast to TCP scaffolds alone, which exhibited poor bone formation when implanted, in the subcutaneous layer both in athymic rats and in the sheep. This technique for preparing highly osteoinductive TCP may promote regeneration in large bone defects.

Lipopolysaccharide Binding Protein Enables Intestinal Epithelial Restitution Despite Lipopolysaccharide Exposure

PubMed Central

Richter, Juli M.; Schanbacher, Brandon L.; Huang, Hong; Xue, Jianjing; Bauer, John A.; Giannone, Peter J.

2011-01-01

Intestinal epithelial restitution is the first part in the process of mucosal repair after injury in the intestine. Integrity of the intestinal mucosal barrier is important as a first line of defense against bacteria and endotoxin. Necrotizing enterocolitis (NEC) is a major cause of morbidity and mortality in extremely low birth weight infants, but its mechanisms are not well defined. Abnormal bacterial colonization, immature barrier function, innate immunity activation and inflammation likely play a role. Lipopolysaccharide (LPS) binding protein (LBP) is secreted by enterocytes in response to inflammatory stimuli and has concentration-dependent effects. At basal concentrations, LBP stimulates the inflammatory response by presenting LPS to its receptor. However, at high concentrations, LBP is able to neutralize LPS and prevent an exaggerated inflammatory response. We sought to determine how LBP would affect wound healing in an in vitro model of intestinal cell restitution and protect against intestinal injury in a rodent model of NEC. Immature intestinal epithelial cells (IEC-6) were seeded in poly-l-lysine coated 8 chamber slides and grown to confluence. A 500μm wound was created using a cell scraper mounted on the microscope to achieve uniform wounding. Media was replaced with media containing LPS +/− LBP. Slide wells were imaged after 0, 8, and 24 hours and then fixed. Cellular restitution was evaluated via digital images captured on an inverted microscope and wound closure was determined by automated analysis. TLR4 was determined by rtPCR after RNA isolation from wounded cells 24 hours after treatment. LPS alone attenuated wound healing in immature intestinal epithelium. This attenuation is reversed by 24 hours with increasing concentrations of LBP so that wound healing is equivalent to control (p< 0.001). TLR4 was increased with LPS alone but levels returned to that of control after addition of LBP in the higher concentrations. LBP had no effect on the development of intestinal injury when given during our rodent model of NEC. Abnormal bacterial colonization and activation of innate immunity by LPS are likely involved in the pathogenesis of NEC. The attentuation of wound healing was reversed when LBP was added to LPS but only in the higher concentrations. At these same concentrations of LBP, TLR4 was decreased to that of control. These results indicate that LBP may be a novel therapeutic strategy to facilitate wound healing after the acute phase of NEC and other forms of intestinal injury. PMID:22002480

Spatial scales of carbon flow in a river food web

USGS Publications Warehouse

Finlay, J.C.; Khandwala, S.; Power, M.E.

2002-01-01

Spatial extents of food webs that support stream and river consumers are largely unknown, but such information is essential for basic understanding and management of lotic ecosystems. We used predictable variation in algal ??13C with water velocity, and measurements of consumer ??13C and ??15N to examine carbon flow and trophic structure in food webs of the South Fork Eel River in Northern California. Analyses of ??13C showed that the most abundant macroinvertebrate groups (collector-gatherers and scrapers) relied on algae from local sources within their riffle or shallow pool habitats. In contrast, filter-feeding invertebrates in riffles relied in part on algal production derived from upstream shallow pools. Riffle invertebrate predators also relied in part on consumers of pool-derived algal carbon. One abundant taxon drifting from shallow pools and riffles (baetid mayflies) relied on algal production derived from the habitats from which they dispersed. The trophic linkage from pool algae to riffle invertebrate predators was thus mediated through either predation on pool herbivores dispersing into riffles, or on filter feeders. Algal production in shallow pool habitats dominated the resource base of vertebrate predators in all habitats at the end of the summer. We could not distinguish between the trophic roles of riffle algae and terrestrial detritus, but both carbon sources appeared to play minor roles for vertebrate consumers. In shallow pools, small vertebrates, including three-spined stickleback (Gasterosteus aculeatus), roach (Hesperoleucas symmetricus), and rough-skinned newts (Taricha granulosa), relied on invertebrate prey derived from local pool habitats. During the most productive summer period, growth of all size classes of steelhead and resident rainbow trout (Oncorhynchus mykiss) in all habitats (shallow pools, riffles, and deep unproductive pools) was largely derived from algal production in shallow pools. Preliminary data suggest that the strong role of shallow pool algae in riffle steelhead growth during summer periods was due to drift of pool invertebrates to riffles, rather than movement of riffle trout. Data for ??15N showed that resident rainbow trout (25-33 cm standard length) in deep pools preyed upon small size classes of juvenile steelhead that were most often found in riffles or shallow pools. While many invertebrate consumers relied primarily on algal production derived from local habitats, our study shows that growth of top predators in the river is strongly linked to food webs in adjacent habitats. These results suggest a key role for emigration of aquatic prey in determining carbon flow to top predators.

Daily and seasonal trends of electricity and water use on pasture-based automatic milking dairy farms.

PubMed

Shortall, J; O'Brien, B; Sleator, R D; Upton, J

2018-02-01

The objective of this study was to identify the major electricity and water-consuming components of a pasture-based automatic milking (AM) system and to establish the daily and seasonal consumption trends. Electricity and water meters were installed on 7 seasonal calving pasture-based AM farms across Ireland. Electricity-consuming processes and equipment that were metered for consumption included milk cooling components, air compressors, AM unit(s), auxiliary water heaters, water pumps, lights, sockets, automatic manure scrapers, and so on. On-farm direct water-consuming processes and equipment were metered and included AM unit(s), auxiliary water heaters, tubular coolers, wash-down water pumps, livestock drinking water supply, and miscellaneous water taps. Data were collected and analyzed for the 12-mo period of 2015. The average AM farm examined had 114 cows, milking with 1.85 robots, performing a total of 105 milkings/AM unit per day. Total electricity consumption and costs were 62.6 Wh/L of milk produced and 0.91 cents/L, respectively. Milking (vacuum and milk pumping, within-AM unit water heating) had the largest electrical consumption at 33%, followed by air compressing (26%), milk cooling (18%), auxiliary water heating (8%), water pumping (4%), and other electricity-consuming processes (11%). Electricity costs followed a similar trend to that of consumption, with the milking process and water pumping accounting for the highest and lowest cost, respectively. The pattern of daily electricity consumption was similar across the lactation periods, with peak consumption occurring at 0100, 0800, and between 1300 and 1600 h. The trends in seasonal electricity consumption followed the seasonal milk production curve. Total water consumption was 3.7 L of water/L of milk produced. Water consumption associated with the dairy herd at the milking shed represented 42% of total water consumed on the farm. Daily water consumption trends indicated consumption to be lowest in the early morning period (0300-0600 h), followed by spikes in consumption between 1100 and 1400 h. Seasonal water trends followed the seasonal milk production curve, except for the month of May, when water consumption was reduced due to above-average rainfall. This study provides a useful insight into the consumption of electricity and water on a pasture-based AM farms, while also facilitating the development of future strategies and technologies likely to increase the sustainability of AM systems. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Acoustic comunication systems and sounds in three species of crickets from central Italy: musical instruments for a three-voices composition

NASA Astrophysics Data System (ADS)

Monacchi, David; Valentini, Laura

2016-04-01

Natural soundscape has always constituted a reference in cognitive and emotional processes. The imitation of natural sounds contributed to the origin of the verbal language, which has been then subjected to an even more refined process of abstraction throughout history. The musical language also evolved along the same path of imitation. Among the many sonic elements of a natural environment, the stridulation of crickets is one of the most consistent for its timbre, articulation, diffusion and intrinsic emotional power. More than 900 species of crickets, in fact, have been described. They can be found in all parts of the world with the exception of cold regions at latitudes higher than 55° North and South. Among the many species we're working on (Order Orthoptera and Suborder Ensifera), we refer here of a comparison between the morphology of the acoustic emission systems and the corresponding waveforms/spectral patterns of sound in three widespread species from central Italy: Gryllus Bimaculatus, Acheta Domesticus (Gryllidae), and Ruspolia Nitidula (Conocephalidae). The samples of the acoustic apparatus of the target individuals, stored in ethanol, were observed under a Field Emission Gun Environmental Electron Scanning Microscope (FEG-ESEM, Quanta 200, FEI, The Netherlands). The use of this type of microscope allowed to analyze the samples without any kind of manipulation (dehydration and/or metallization), while maintaining the morphological features of the fragile acoustic apparatus. The observations were made with different sensors (SE: secondary-electron sensor and BSE: backscattered-electron sensor), and performed at low-medium vacuum with energies varying from c.ca 10 to 30kV. Male individuals have an acoustic apparatus consisting in two cuticular structures (tegmina) positioned above wings, while both male and females have receiving organs (tympanum) in forelegs. Stridulation mechanism is produced when the file and the scraper (plectrum) scrub one another. File morphology is one of the main distinctive element in sound emission strategies of insect species. We compared analyses of the microstructures of different species' files (both shape and height of teeth, regularity, distance, etc.) and then confirmed their main characteristics within the acoustic domain. Specific Fourier transforms were employed to derive detailed spectrograms analyses providing a powerful visual tool for understanding. For the three species in this study, the typical stridulation of male individuals were isolated and recorded in high definition (96khz and 192khz / 24bit). These high sampling rates enabled to enter the microcosm of sound - in analogy to the microcosm of morphology - through processes of time and frequency shifting. Different sound design methodologies, then, allowed to compose an imaginary soundscape where the sonic gestures of each individual (or more grouped recordings) were superimposed in a polyphony of rhythms and pitches. The purpose for crossing bioacoustics, electron microscopy and music in this interdisciplinary work is driven by a pressing need of awareness of the sonic heritage of landscapes and its conservation.

Design and fabrication of magnetic coolant filter

NASA Astrophysics Data System (ADS)

Prashanth, B. N.

2017-07-01

Now a day's use of coolants in industry has become dominant because of high production demands. Coolants not only help in speeding up the production but also provide many advantages in the metal working operation. As the consumption of coolants is very high a system is badly in need, so as to recirculate the used coolant. Also the amount of hazardous waste generated by industrial plants has become an increasingly costly problem for the manufactures and an additional stress on the environment. Since the purchase and disposal of the spent cutting fluids is becoming increasingly expensive, fluid recycling is a viable option for minimizing the cost. Separation of metallic chips from the coolants by using magnetic coolant separation has proven a good management and maintenance of the cutting fluid. By removing the metallic chips, the coolant life is greatly extended, increases the machining quality and reduces downtime. Above being the case, a magnetic coolant filter is developed which utilizes high energy permanent magnets to develop a dense magnetic field along a narrow flow path into which the contaminated coolant is directed. The ferromagnetic particles captured and aligned by the dense magnetic field, from the efficient filter medium. This enables the unit to remove ferromagnetic particles from the coolant. Magnetic coolant filters use the principle of magnetic separation to purify the used coolant. The developed magnetic coolant separation has the capability of purifying 40 litres per minute of coolant with the size of the contaminants ranging from 1 µm to 30 µm. The filter will be helpful in saving the production cost as the cost associated with the proposed design is well justified by the cost savings in production. The magnetic field produced by permanent magnets will be throughout the area underneath the reservoir. This produces magnetic field 30mm above the coolant reservoir. Very fine particles are arrested without slip. The magnetic material used will not lose its strength even number of years of use. Dirty coolant is fed from the machines in to the reservoir of the coolant filter either by a pump or taken by the gravity and flows under the tray. This attracts the ferrous particles and builds up a cake of ferrous material and finally taken away by the scraper. The moving permanent magnets mounted on the shaft attracts ferrous chips and slide them on to plate and then to the discharge end or sludge bin. The coolant separated from chips flow back to the coolant tank. Well in this fast changing growth of metal working operation the recycling of cutting fluids become very important for the management of coolant. With the help of this developed model of magnetic coolant separator we can get highly efficient way of filtration guarantying fine finish, dimensional accuracy and increased tool life. The most significant role of this filter is that, it will reduce the waste disposal of coolant and a net profit for the production industries.

Influence of secondary settling tank performance on suspended solids mass balance in activated sludge systems.

PubMed

Patziger, M; Kainz, H; Hunze, M; Józsa, J

2012-05-01

Secondary settling is the final step of the activated sludge-based biological waste water treatment. Secondary settling tanks (SSTs) are therefore an essential unit of producing a clear effluent. A further important function of SSTs is the sufficient thickening to achieve highly concentrated return sludge and biomass within the biological reactor. In addition, the storage of activated sludge is also needed in case of peak flow events (Ekama et al., 1997). Due to the importance of a high SST performance the problem has long been investigated (Larsen, 1977; Krebs, 1991; Takács et al., 1991; Ekama et al., 1997; Freimann, 1999; Patziger et al., 2005; Bürger et al., 2011), however, a lot of questions are still to solve regarding e.g. the geometrical features (inflow, outflow) and operations (return sludge control, scraper mechanism, allowable maximum values of surface overflow rates). In our study we focused on SSTs under dynamic load considering both the overall unsteady behaviour and the features around the peaks, investigating the effect of various sludge return strategies as well as the inlet geometry on SST performance. The main research tool was a FLUENT-based novel mass transport model consisting of two modules, a 2D axisymmetric SST model and a mixed reactor model of the biological reactor (BR). The model was calibrated and verified against detailed measurements of flow and concentration patterns, sludge settling, accompanied with continuous on-line measurement of in- and outflow as well as returned flow rates of total suspended solids (TSS) and water. As to the inlet arrangement a reasonable modification of the geometry could result in the suppression of the large scale flow structures of the sludge-water interface thus providing a significant improvement in the SST performance. Furthermore, a critical value of the overflow rate (q(crit)) was found at which a pronounced large scale circulation pattern develops in the vertical plane, the density current in such a way hitting the outer wall of the SST, turning then to the vertical direction accompanied with significant flow velocities. This phenomenon strengthens with the hydraulic load and can entrain part of the sludge thus resulting in unfavourable turbid effluent. As a representative case study an operating circular SST most commonly used in practice was investigated. Focusing on the sludge return strategies, it was found that up to a threshold peak flow rate the most efficient way is to keep the return sludge flow rate constant, at 0.4Q(MAX). However, once the inflow rate exceeds the threshold value the return sludge flow rate should be slowly increased up to 0.6Q(MAX), performed in a delayed manner, about 20-30 min after the threshold value is exceeded. For preserving the methodology outlined in the present paper, other types of SSTs, however, need further individual investigations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Associations of dairy cow behavior, barn hygiene, cow hygiene, and risk of elevated somatic cell count.

PubMed

Devries, T J; Aarnoudse, M G; Barkema, H W; Leslie, K E; von Keyserlingk, M A G

2012-10-01

Poor dairy cow hygiene has been consistently associated with elevated somatic cell count (SCC) and the risk of subclinical mastitis. The objective of this study was to determine the associations between dairy cow standing and lying behavior, barn hygiene, cow hygiene, and the risk of experiencing elevated SCC. Lactating Holstein dairy cows (n=69; 86 ± 51 DIM; parity: 2.0 ± 1.2; means ± SD), kept in 1 of 2 groups, were monitored over a 4-mo period. Each group contained 61 ± 1 (mean ± SD) cows over the study period; complete data were obtained from 37 and 32 animals within each respective group. Cows were housed in a sand-bedded, freestall barn with 2 symmetrical pens, each with a free cow traffic automatic milking system. To vary barn hygiene, in 4 consecutive 28-d periods, alley manure scrapers in each of the 2 pens were randomly assigned to frequencies of operation of 3, 6, 12, and 24 times per day. During the last 7 d of each period, cow hygiene (upper leg/flank, lower legs, and udder; scale of 1 = very clean to 4 = very dirty) and stall hygiene (number of 0.15×0.15-m squares contaminated with manure in a 1.20×1.65-m grid) were recorded. Standing and lying behavior of the cows were collected during those days using data loggers. Individual-cow SCC was recorded at the beginning and end of each 28-d period. Elevated SCC was used as an indicator of subclinical mastitis; incidence of elevated SCC was defined as having a SCC >200,000 cells/mL at the end of each 28-d period, when SCC was <100,000 cells/mL at the beginning of the period. Less frequent scraping of the barn alleys was associated with cows having poorer hygiene. Poor udder hygiene was associated with poor stall hygiene. Longer lying duration was associated with poor hygiene of the upper legs/flank and udder. Greater premilking standing duration was associated with poor udder hygiene and decreased frequency of lying bouts was associated with poor hygiene of the lower legs. Higher milk yield was associated with poor hygiene of the udder and lower legs; multiparous cows had poorer hygiene of the upper legs/flank and udder. Over the study period, 24 new cases of elevated SCC were detected. No associations existed for the risk of experiencing an elevated SCC with alley scraping frequency or cow behavior patterns. However, increased odds of occurrence of elevated SCC were noted for cows of lower milk yield as well as for multiparous cows. In summary, these results show that cow hygiene is affected by the standing and lying behavior of cows and by the cleanliness of the cow's environment. These findings emphasize the need for cows to be provided clean standing and lying environments. The results also show that frequent cleaning of barn alley floors will help improve cow hygiene. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Variability in Lotic Communities in Three Contrasting Stream Environments in the Santa Ana River Basin, California, 1999-2001

USGS Publications Warehouse

Burton, Carmen A.

2008-01-01

Biotic communities and environmental conditions can be highly variable between natural ecosystems. The variability of natural assemblages should be considered in the interpretation of any ecological study when samples are either spatially or temporally distributed. Little is known about biotic variability in the Santa Ana River Basin. In this report, the lotic community and habitat assessment data from ecological studies done as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program are used for a preliminary assessment of variability in the Santa Ana Basin. Habitat was assessed, and benthic algae, benthic macroinvertebrate, and fish samples were collected at four sites during 1999-2001. Three of these sites were sampled all three years. One of these sites is located in the San Bernardino Mountains, and the other two sites are located in the alluvial basin. Analysis of variance determined that the three sites with multiyear data were significantly different for 41 benthic algae metrics and 65 macroinvertebrate metrics and fish communities. Coefficients of variation (CVs) were calculated for the habitat measurements, metrics of benthic algae, and macroinvertebrate data as measures of variability. Annual variability of habitat data was generally greater at the mountain site than at the basin sites. The mountain site had higher CVs for water temperature, depth, velocity, canopy angle, streambed substrate, and most water-quality variables. In general, CVs of most benthic algae metrics calculated from the richest-targeted habitat (RTH) samples were greater at the mountain site. In contrast, CVs of most benthic algae metrics calculated from depositional-targeted habitat (DTH) samples were lower at the mountain site. In general, CVs of macroinvertebrate metrics calculated from qualitative multihabitat (QMH) samples were lower at the mountain site. In contrast, CVs of many metrics calculated from RTH samples were greater at the mountain site than at one of the basin sites. Fish communities were more variable at the basin sites because more species were present at these sites. Annual variability of benthic algae metrics was related to annual variability in habitat variables. The CVs of benthic algae metrics related to the most CVs of habitat variables included QMH taxon richness, the RTH percentage richness, RTH abundance of tolerant taxa, RTH percentage richness of halophilic diatoms, RTH percentage abundance of sestonic diatoms, DTH percentage richness of nitrogen heterotrophic diatoms, and DTH pollution tolerance index. The CVs of macroinvertebrate metrics related to the most CVs of habitat variables included the RTH trichoptera, RTH EPT, RTH scraper richness, RTH nonchironomid dipteran abundance (in percent), and RTH EPA (U.S. Environmental Protection Agency) tolerance, which is based on abundance. Many of the CVs of habitat variables related to CVs of macroinvertebrate metrics were the same habitat variables that were related to the CVs of benthic algae metrics. On the basis of these results, annual variability may have a role in the relationship of benthic algae and macroinvertebrates assemblages with habitat and water quality in the Santa Ana Basin. This report provides valuable baseline data on the variability of biological communities in the Santa Ana Basin.

Design Drivers of Water Data Services

NASA Astrophysics Data System (ADS)

Valentine, D.; Zaslavsky, I.

2008-12-01

The CUAHSI Hydrologic Information System (HIS) is being developed as a geographically distributed network of hydrologic data sources and functions that are integrated using web services so that they function as a connected whole. The core of the HIS service-oriented architecture is a collection of water web services, which provide uniform access to multiple repositories of observation data. These services use SOAP protocols communicating WaterML (Water Markup Language). When a client makes a data or metadata request using a CUAHSI HIS web service, these requests are made in standard manner, following the CUAHSI HIS web service signatures - regardless of how the underlying data source may be organized. Also, regardless of the format in which the data are returned by the source, the web services respond to requests by returning the data in a standard format of WaterML. The goal of WaterML design has been to capture semantics of hydrologic observations discovery and retrieval and express the point observations information model as an XML schema. To a large extent, it follows the representation of the information model as adopted by the CUASHI Observations Data Model (ODM) relational design. Another driver of WaterML design is specifications and metadata adopted by USGS NWIS, EPA STORET, and other federal agencies, as it seeks to provide a common foundation for exchanging both agency data and data collected in multiple academic projects. Another WaterML design principle was to create, in version 1 of HIS in particular, a fairly rigid and simple XML schema which is easy to generate and parse, thus creating the least barrier for adoption by hydrologists. WaterML includes a series of elements that reflect common notions used in describing hydrologic observations, such as site, variable, source, observation series, seriesCatalog, and data values. Each of the three main request methods in the water web services - GetSiteInfo, GetVariableInfo, and GetValues - has a corresponding response element in WaterML: SitesResponse, VariableResponse, and TimeSeriesResponse. The WaterML specification is being adopted by federal agencies. The experimental USGS NWIS Daily Values web service returns WaterML-compliant TImeSeriesResponse. The National Climatic Data Center is also prototyping WaterML for data delivery, and has developed a REST-based service that generates WaterML- compliant output for the NCDC ASOS network. Such agency-supported web services coming online provide a much more efficient way to deliver agency data compared to the web site scraper services that the CUAHSI HIS project has developed initially. The CUAHSI water data web services will continue to serve as the main communication mechanism within CUAHSI HIS, connecting a variety of data sources with a growing set of web service clients being developed in both academia and the commercial sector. The driving forces for the development of web services continue to be: - Application experience and needs of the growing number of CUAHSI HIS users, who experiment with additional data types, analysis modes, data browsing and searching strategies, and provide feedback to WaterML developers; - Data description requirements posed by various federal and state agencies; - Harmonization with standards being adopted or developed in neighboring communities, in particular the relevant standards being explored within the Open Geospatial Consortium. CUAHSI WaterML is a standard output schema for CUAHSI HIS water web services. Its formal specification is available as OGC discussion paper at www.opengeospatial.org/standards/dp/ class="ab'>

Characterization of water quality and biological communities, Fish Creek, Teton County, Wyoming, 2007-2011

USGS Publications Warehouse

Eddy-Miller, Cheryl A.; Peterson, David A.; Wheeler, Jerrod D.; Edmiston, C. Scott; Taylor, Michelle L.; Leemon, Daniel J.

2013-01-01

Fish Creek, an approximately 25-kilometer-long tributary to Snake River, is located in Teton County in western Wyoming near the town of Wilson. Fish Creek is an important water body because it is used for irrigation, fishing, and recreation and adds scenic value to the Jackson Hole properties it runs through. Public concern about nuisance growths of aquatic plants in Fish Creek has been increasing since the early 2000s. To address these concerns, the U.S. Geological Survey conducted a study in cooperation with the Teton Conservation District to characterize the hydrology, water quality, and biologic communities of Fish Creek during 2007–11. The hydrology of Fish Creek is strongly affected by groundwater contributions from the area known as the Snake River west bank, which lies east of Fish Creek and west of Snake River. Because of this continuous groundwater discharge to the creek, land-use activities in the west bank area can affect the groundwater quality. Evaluation of nitrate isotopes and dissolved-nitrate concentrations in groundwater during the study indicated that nitrate was entering Fish Creek from groundwater, and that the source of nitrate was commonly a septic/sewage effluent or manure source, or multiple sources, potentially including artificial nitrogen fertilizers, natural soil organic matter, and mixtures of sources. Concentrations of dissolved nitrate and orthophosphate, which are key nutrients for growth of aquatic plants, generally were low in Fish Creek and occasionally were less than reporting levels (not detected). One potential reason for the low nutrient concentrations is that nutrients were being consumed by aquatic plant life that increases during the summer growing season, as a result of the seasonal increase in temperature and larger number of daylight hours. Several aspects of Fish Creek’s hydrology contribute to higher productivity and biovolume of aquatic plants in Fish Creek than typically observed in streams of its size in Wyoming. Especially in the winter, the proportionately large, continuous gain of groundwater into Fish Creek in the perennial section keeps most of the creek free of ice. Because sunlight can still reach the streambed in Fish Creek and the water is still flowing, aquatic plants continue to photosynthesize in the winter, albeit at a lower level of productivity. Additionally, the cobble and large gravel substrate in Fish Creek provides excellent attachment points for aquatic plants, and when combined with Fish Creek’s channel stability allows rapid growth of aquatic plants once conditions allow during the spring. The aquatic plant community of Fish Creek was different than most streams in Wyoming in that it contains many different macrophytes—including macroalgae such as long streamers of Cladophora, aquatic vascular plants, and moss; most other streams in the state contain predominantly algae. From the banks of Fish Creek, the bottom of the stream sometimes appeared to be a solid green carpet. A shift was observed from higher amounts of microalgae in April/May to higher amounts macrophytes in August and October, and differences in the relative abundance of microalgae and macrophytes were statistically significant between seasons. Differences in dissolved-nitrate concentrations and in the nitrogen-to-phosphorus ratio were significantly different between seasons, as concentrations of dissolved nitrate decreased from April/May to August and October. It is likely that dissolved-nitrate concentrations in Fish Creek were lower in August and October because macrophytes were quickly utilizing the nutrient, and a negative correlation between macro-phytes and nitrate was found. Macroinvertebrates also were sampled because of their role as indicators of water quality and their documented responses to perturbation such as degradation of water quality and habitat. Statistically significant seasonal differences were noted in the macroinvertebrate community. Taxa richness and relative abundance of Ephemeroptera, Plecoptera, and Trichoptera, which tend to be intolerant of water-quality degradation, decreased from April/May to August; the same time period saw a corresponding increase in Diptera and noninsects, particularly Oligochaeta (worms) that are more tolerant. Seasonal changes in macroinvertebrate functional feeding groups were significantly different. The relative abundance of gatherer-collector and scraper feeding groups decreased from April/May to August, accompanied by an increase in filterer-collector and shredders feeding groups. Seasonal changes in feeding groups might be due to the seasonal shift in aquatic plant communities, as indicated by comparison with other streams in the area that had fewer aquatic macrophytes than Fish Creek. Statistical tests of macroinvertebrate metrics indicated few differences between years or biological sampling sites on Fish Creek, although the site farthest upstream sometimes was different not only in terms of macroinvertebrates but also in streamflow, water quality, and aquatic plants. Potential effects of contributions of additional nutrients to the Fish Creek ecosystem beyond the conditions sampled during the study period are not known. However, because virtually all of the detectable dissolved nitrate commonly was consumed by aquatic plants in August (leaving dissolved nitrate less than the reporting level in water samples), it is possible that increased nutrient contributions could cause increased growth of aquatic plants. Additional long-term monitoring of the stream, with concurrent data analysis and interpretation would be needed to determine the effects of additional nutrients on the aquatic plant community and on higher levels of the food chain.

The evolution of the CUAHSI Water Markup Language (WaterML)

NASA Astrophysics Data System (ADS)

Zaslavsky, I.; Valentine, D.; Maidment, D.; Tarboton, D. G.; Whiteaker, T.; Hooper, R.; Kirschtel, D.; Rodriguez, M.

2009-04-01

The CUAHSI Hydrologic Information System (HIS, his.cuahsi.org) uses web services as the core data exchange mechanism which provides programmatic connection between many heterogeneous sources of hydrologic data and a variety of online and desktop client applications. The service message schema follows the CUAHSI Water Markup Language (WaterML) 1.x specification (see OGC Discussion Paper 07-041r1). Data sources that can be queried via WaterML-compliant water data services include national and international repositories such as USGS NWIS (National Water Information System), USEPA STORET (Storage & Retrieval), USDA SNOTEL (Snowpack Telemetry), NCDC ISH and ISD(Integrated Surface Hourly and Daily Data), MODIS (Moderate Resolution Imaging Spectroradiometer), and DAYMET (Daily Surface Weather Data and Climatological Summaries). Besides government data sources, CUAHSI HIS provides access to a growing number of academic hydrologic observation networks. These networks are registered by researchers associated with 11 hydrologic observatory testbeds around the US, and other research, government and commercial groups wishing to join the emerging CUAHSI Water Data Federation. The Hydrologic Information Server (HIS Server) software stack deployed at NSF-supported hydrologic observatory sites and other universities around the country, supports a hydrologic data publication workflow which includes the following steps: (1) observational data are loaded from static files or streamed from sensors into a local instance of an Observations Data Model (ODM) database; (2) a generic web service template is configured for the new ODM instance to expose the data as a WaterML-compliant water data service, and (3) the new water data service is registered at the HISCentral registry (hiscentral.cuahsi.org), its metadata are harvested and semantically tagged using concepts from a hydrologic ontology. As a result, the new service is indexed in the CUAHSI central metadata catalog, and becomes available for spatial and semantics-based queries. The main component of interoperability across hydrologic data repositories in CUAHSI HIS is mapping different repository schemas and semantics to a shared community information model for observations made at stationary points. This information model has been implemented as both a relational schema (ODM) and an XML schema (WaterML). Its main design drivers have been data storage and data interchange needs of hydrology researchers, a series of community reviews of the ODM, and the practices of hydrologic data modeling and presentation adopted by federal agencies as observed in agency online data access applications, such as NWISWeb and USEPA STORET. The goal of the first version of WaterML was to encode the semantics of hydrologic observations discovery and retrieval and implement water data services in a way that is generic across different data providers. In particular, this implied maintaining a single common representation for the key constructs returned to web service calls, related to observations, features of interest, observation procedures, observation series, etc. Another WaterML design consideration was to create (in version 1 of CUAHSI HIS in particular) a fairly rigid, compact, and simple XML schema which was easy to generate and parse, thus creating the least barrier for adoption by hydrologists. Each of the three main request methods in the water data web services - GetSiteInfo, GetVariableInfo, and GetValues - has a corresponding response element in WaterML: SiteResponse, VariableResponse, and TimeSeriesResponse. The strictness and compactness of the first version of WaterML supported its community adoption. Over the last two years, several ODM and WaterML implementations for various platforms have emerged, and several Water Data Services client applications have been created by outside groups in both industry and academia. In a significant development, the WaterML specification has been adopted by federal agencies. The experimental USGS NWIS Daily Values web service returns WaterML-compliant TimeSeriesResponse. NCDC is also prototyping WaterML for data delivery, and has developed a REST-based service that generates WaterML- compliant output for its integrated station network. These agency-supported web services provide a much more efficient way to deliver agency data compared to the web site scraper services that the CUAHSI HIS project developed initially. Adoption of WaterML by the US Geological Survey is particularly significant because the USGS maintains by far the largest water data repository in the United States. For version 1.1, WaterML has evolved to reflect the deployment experience at hydrologic observatory testbeds, as well as feedback from hydrologic data repository managers at federal and state agencies. Further development of WaterML and enhancement of the underlying information model is the focus of the recently established OGC Hydrology Domain Working Group, whose mission is to profile OGC standards (GML, O&M, SOS, WCS, WFS) for the water resources domain and thus ensure WaterML's wider applicability and easier implementation. WaterML 2.0 is envisioned as an OGC-compliant application schema that supports OGC features, can express different types of observations and various groupings of observations, and allows researchers to define custom metadata elements. This presentation will discuss the information model underlying WaterML and describe the rationale, design drivers and evolution of WaterML and the water data services, illustrating their recent application in the context of CUAHSI HIS and the hydrologic observatory testbeds.

Dynamics of Non-Uniformity Loads of Afc Drives

NASA Astrophysics Data System (ADS)

Dolipski, Marian; Remiorz, Eryk; Sobota, Piotr

2014-03-01

The length of armoured face conveyors currently used in hard coal mines most often ranges between 200 m and 300 m. The machines are equipped with a main and auxiliary drive. Asynchronous motors mounted in conveyor drives feature the capacity of several hundreds of kilowatts. The non-uniform distribution of loads onto individual drives is observed in practice. The numerical value of loads distribution onto the individual armoured face conveyor drives is represented by a drive load distribution factor. It is defined as a ratio between the load of an electric motor installed in a given drive and the total conveyor load. The article presents a physical armoured face conveyor model intended for examining dynamic phenomena influencing the load non-uniformity of drives. Motion in this physical model is described with the system of (4 · j + 5) non-linear ordinary differential quotations of the second order. A mathematical model is obtained by adding functions describing the interwork of sprocket drums with chains and functions approximating the mechanical characteristics of asynchronous motors powered by means of frequency inverters. A large number of computer simulations was performed using this model enabling to study the impact on the load non-uniformity of drives of such parameters as motor slip, motor supply voltage drop, variations in supply voltage frequency, differences in the gear ratio of transmissions and differentiation in the pitch of scraper chain links along the chain contour. Długość przenośników zgrzebłowych ścianowych stosowanych obecnie w kopalniach węgla kamiennego najczęściej mieści się w przedziale od 200 m do 300 m. Maszyny te wyposażone są zawsze w napęd główny i pomocniczy, przy czym pierwszy z nich wyniesiony jest do chodnika podścianowego. Silniki napędowe o mocy kilkuset kilowatów napędzają bęben łańcuchowy przez sprzęgło i przekładnię zębatą. Z kolei bębny łańcuchowe poruszają łańcuch zgrzebłowy, który tworzą dwa środkowe łańcuchy ogniwowe ze zgrzebłami przymocowanymi do ogniw poziomych łańcuchów. Ze względu na znaczne wydłużenia sprężyste łańcucha zgrzebłowego obciążonego urobkiem węglowym, konieczne jest jego wstępne napinanie. W zależności od wartości napięcia wstępnego łańcucha zgrzebłowego, oporów ruchu w gałęzi górnej i dolnej przenośnika oraz występujących drgań wzdłużnych, łańcuch może się znajdować w jednym z trzech stanów dynamicznych: w stanie stałego luzowania, w stanie okresowego luzowania lub w stanie nieluzowania. W przenośnikach ścianowych obserwuje się nierównomierny rozdział obciążeń na poszczególne napędy. Jego liczbową miarą jest współczynnik rozdziału obciążenia napędu. Jest on definiowany, jako stosunek obciążenia silnika elektrycznego zainstalowanego w danym napędzie do całkowitego obciążenia przenośnika (wzory 1 i 2). W praktyce niemożliwa staje się eliminacja wszystkich przyczyn nierównomiernego obciążenia napędu głównego i pomocniczego w przenośniku ścianowym. Wobec tego podejmuje się działania mające na celu wyrównywanie obciążeń napędów poprzez sterowanie wybranymi parametrami techniczno-ruchowymi przenośnika ścianowego. Badania komputerowe za pomocą własnego modelu dynamicznego wykazały, że jest to możliwe. Tymi parametrami są częstotliwości napięcia zasilania silników asynchronicznych, które powodują zmiany prędkości kątowych bębnów łańcuchowych. W artykule przedstawiono model fizyczny ścianowego przenośnika zgrzebłowego przeznaczony do badania zjawisk dynamicznych wpływających na nierównomierność obciążenia napędów (rys. 1). Opis ruchu w tym modelu fizycznym tworzy układ (4 · j + 5) nieliniowych równań różniczkowych zwyczajnych drugiego rzędu. Dokładając do tego funkcje opisujące współdziałanie bębnów łańcuchowych z łańcuchami oraz funkcje aproksymujące charakterystyki mechaniczne silników asynchronicznych zasilanych za pomocą przemienników częstotliwości (wzory od 3 do 9) otrzymuje się model matematyczny. Za pomocą tego modelu matematycznego wykonano dużą liczbę symulacji komputerowych umożliwiających badanie wpływu takich parametrów jak poślizg silnika, spadek napięcia zasilania silnika, zmiana częstotliwości napięcia zasilającego, różnica w przełożeniu reduktorów i zróżnicowanie podziałek ogniw łańcucha zgrzebłowego wzdłuż konturu łańcuchowego na nierównomierność obciążenia napędów. Na rysunkach od 4 do 10 pokazano wybrane charakterystyki czasowe przedstawiające wpływ wyżej wymienionych parametrów na nierównomierność obciążenia napędów w przenośniku ścianowym.

Determination of the Friction Work of a Link Chain Interworking with a Sprocket Drum / Wyznaczenie Pracy Tarcia Łańcucha Ogniwowego We Współdziałaniu Z Bębnem Łańcuchowym

NASA Astrophysics Data System (ADS)

Sobota, Piotr

2013-09-01

The significant abrasive wear of sprocket drum teeth and seats bottoms is observed during the exploitation of longwall scraper conveyors. For this reason, it is important to determine friction work in sliding conditions of the horizontal link on the tooth seat bottom and on the tooth flank and friction work in the joint of links in the context of such nodes' abrasive wear. The different construction variants of sprocket drums can be compared by determining friction work in the sliding positions of the horizontal link on the drum. The determination of the losses of the power transmitted is a requisite condition in such situation for determining the efficiency values of chain meshing. The friction work of the friction couple of a sprocket drum - link chain consists of friction work of the horizontal link in the places where it contacts with the seat bottom Ag and the tooth flank Af and friction work in the joints of a horizontal link in the contact place with vertical links: in the front joint Ap and the rear joint At. The article presents dependencies enabling to determine the value of such work for specific geometric relations between the chain and the drum and different friction conditions. The curves of relative friction work and the values of total friction work on the seat bottom, on the tooth flank and in a front and rear joint of links are presented for examples of friction conditions. W czasie eksploatacji ścianowych przenośników zgrzebłowych obserwuje się znaczne zużycia ścierne powierzchni zębów i den gniazd bębnów łańcuchowych. Z tych powodów ważne jest określenie pracy tarcia w warunkach poślizgu ogniwa poziomego na dnie gniazda i na flance zęba oraz pracy tarcia w przegubach ogniw w aspekcie zużycia ściernego tych węzłów. Wyznaczenie pracy tarcia w miejscach poślizgu ogniwa poziomego na bębnie daje możliwość porównania różnych wariantów konstrukcyjnych bębnów łańcuchowych. Określenie strat przenoszonej mocy jest przy tym istotnym warunkiem określenia wartości sprawności zazębienia łańcuchowego. Na pracę tarcia pary ciernej bęben łańcuchowy - łańcuch ogniwowy składa się praca tarcia ogniwa poziomego w miejscach jego kontaktu z dnem gniazda Ag i flanką zęba Af oraz praca tarcia w przegubach ogniwa poziomego w miejscach kontaktu z ogniwami pionowymi: w przegubie przednim Ap i w przegubie tylnym At. W artykule przedstawiono zależności umożliwiające wyznaczenie wartości tych prac dla określonych relacji geometrycznych pomiędzy łańcuchem a bębnem i różnych warunków tarcia. Dla przykładowych warunków tarcia, zaprezentowano przebiegi względnej pracy tarcia oraz wartości sumarycznej pracy tarcia na dnie gniazda, na flance zęba oraz w przegubie przednim i tylnym ogniw. W czasie eksploatacji ścianowego przenośnika zgrzebłowego następuje - głównie na skutek zużycia - zwiększenie podziałki łańcucha ogniwowego. Zwiększenie długości podziałki łańcucha wynoszące Δp najczęściej opisuje się względnym zwiększeniem podziałki odniesionym do podziałki technologicznej Δp/p i wyrażonym w procentach. Podczas współdziałania bębna łańcuchowego o wymiarach normowych z łańcuchem o zwiększonej podziałce nabiegające ogniwo poziome nie styka się z dnem gniazda na całej swej długości. To zazębienie charakteryzuje się tym, że ogniwa poziome łańcucha znajdujące się na bębnie łańcuchowym o liczbie zębów z są nachylone względem den gniazd pod kątem ɛ tak, że ich torusy przednie stykają się dnami gniazd a torusy tylne stykają się z bokami roboczymi segmentów zębów bębna o kącie pochylenia względem dna gniazda β. W celu jednoznacznego opisu położenia ogniw łańcucha w gniazdach bębna (rys. 1) wyznaczyć należy kąt nachylenia ogniw względem den gniazd koła ɛ, odległość środka przegubu przy torusie przednim ogniwa poziomego od początku boku wieloboku foremnego u oraz kąt obrotu ogniwa pionowego względem poprzedzającego ogniwa poziomego w środku przegubu przy torusie tylnym ogniwa poziomego αu. Im większe wydłużenie względne podziałki tym większe wartości osiągają parametry opisujące położenie ogniw w gniazdach koła łańcuchowego (ɛ, u oraz αu). Ze względu na powtarzalność położenia ogniw w gniazdach bębna łańcuchowego o liczbie zębów z podczas nabiegania łańcucha następuje cykliczne obciążanie kolejnych den gniazd, flanek zębów i ogniw w czasie obrotu bębna łańcuchowego o kąt podziałowy φ = 2π/z. W zakresie obrotu bębna łańcuchowego o kąt podziałowy wyróżniono trzy przedziały charakteryzujące się odmiennym sposobem obciążenia elementów bębna łańcuchowego (rys. 2÷4). Poślizg torusa przedniego ogniwa poziomego na dnie gniazda ma miejsce w pierwszym przedziale obciążenia bębna o kąt podziałowy. W przedziale tym wyróżnić można w przegubie przednim dwie fazy: toczenia i poślizgu ogniw. Wyznaczono drogę tarcia oraz pracę tarcia na dnie gniazda podczas toczenia się ogniw oraz podczas poślizgu ogniw w przegubie przednim (zależności 5÷17). Wykorzystując te zależności wyznaczono drogę tarcia i pracę tarcia na dnie gniazda bębna łańcuchowego o liczbie zębów z = 7, współdziałającego z łańcuchem wielkości 34 ×126 mm o podziałkach ogniw wydłużonych o Δp/p = 0,5% i Δp/p = 3,0%. Pracę tarcia na dnie gniazda Ag wyznaczono całkując numerycznie iloczyn drogi tarcia i odpowiedniej wartości siły R w punkcie styku ogniwa z dnem gniazda. Z powodu względnego określenie siły w punkcie styku w stosunku do wartości siły nabiegającej R/SH również pracę tarcia wyznaczono jako względną w stosunku do siły nabiegającej jako Ag /SH. Względną pracę tarcia na dnie gniazda wyznaczono w funkcji kąta obrotu bębna dla różnych wartości współczynnika tarcia na dnia gniazda (rys. 8÷9). Od chwili, w której wartość siły R spada do zera przy kącie obrotu bębna φR0, rozpoczyna się przedział trzeci kąta podziałowego, w którym na flance zęba pojawia się siła T prostopadła do reakcji F i skierowana w stronę głowy zęba, niezbędna do utrzymania ogniwa poziomego w równowadze (rys. 4). Zapobiega ona poślizgowi torusa tylnego ogniwa poziomego po flance zęba w stronę dna gniazda. Sformułowano warunek wystąpienia poślizgu torusa tylnego ogniwa poziomego po flance zęba i wyznaczono drogę poślizgu i względną pracę tarcia Af /SH dla tego przypadku (zależności 20÷21). W czasie obrotu bębna łańcuchowego o kąt podziałowy następuje wzajemny obrót ogniwa poziomego względem poprzedzającego go ogniwa pionowego w przegubie przednim oraz wzajemny obrót ogniwa pionowego następującego po ogniwie poziomym wokół torusa tylnego ogniwa poziomego w przegubie tylnym. W obydwóch przegubach wyróżnić można dwie fazy obrotu ogniw: toczenia się i poślizgu ogniw w przegubie. Wyznaczono sumaryczną pracę tarcia w przegubie przednim Ap, będącą sumą pracy tarcia przy toczeniu i poślizgu ogniw (zależności 22÷26) oraz pracę tarcia w przegubie tylnym At (zależności 30÷39). Dla określonych warunków tarcia oraz obciążenia ogniw wyznaczono względną pracę tarcia w przegubie przednim Ap /SH i tylnym At /SH przy obrocie bębna łańcuchowego o kąt podziałowy (rys. 12÷13).