In vitro sealing of iatrogenic fetal membrane defects by a collagen plug imbued with fibrinogen and plasma.

PubMed

Engels, A C; Hoylaerts, M F; Endo, M; Loyen, S; Verbist, G; Manodoro, S; DeKoninck, P; Richter, J; Deprest, J A

2013-02-01

We aimed to demonstrate local thrombin generation by fetal membranes, as well as its ability to generate fibrin from fibrinogen concentrate. Furthermore, we aimed to investigate the efficacy of collagen plugs, soaked with plasma and fibrinogen, to seal iatrogenic fetal membrane defects. Thrombin generation by homogenized fetal membranes was measured by calibrated automated thrombography. To identify the coagulation caused by an iatrogenic membrane defect, we analyzed fibrin formation by optical densitometry, upon various concentrations of fibrinogen. The ability of a collagen plug soaked with fibrinogen and plasma was tested in an ex vivo model for its ability to seal an iatrogenic fetal membrane defect. Fetal membrane homogenates potently induced thrombin generation in amniotic fluid and diluted plasma. Upon the addition of fibrinogen concentrate, potent fibrin formation was triggered. Measured by densiometry, fibrin formation was optimal at 1250 µg/mL fibrinogen in combination with 4% plasma. A collagen plug soaked with fibrinogen and plasma sealed an iatrogenic membrane defect about 35% better than collagen plugs without these additives (P = 0.037). These in vitro experiments suggest that the addition of fibrinogen and plasma may enhance the sealing efficacy of collagen plugs in closing iatrogenic fetal membrane defects. © 2013 John Wiley & Sons, Ltd.

Mating Plugs in Polyandrous Giants: Which Sex Produces Them, When, How and Why?

PubMed Central

Kuntner, Matjaž; Kralj-Fišer, Simona; Li, Daiqin

2012-01-01

Background Males usually produce mating plugs to reduce sperm competition. However, females can conceivably also produce mating plugs in order to prevent unwanted, superfluous and energetically costly matings. In spiders–appropriate models for testing plugging biology hypotheses–mating plugs may consist of male genital parts and/or of amorphous covers consisting of glandular or sperm secretions. In the giant wood spider Nephila pilipes, a highly sexually dimorphic and polygamous species, males are known to produce ineffective embolic plugs through genital damage, but nothing is known about the origin and function of additional conspicuous amorphous plugs (AP) covering female genitals. Methodology We tested alternative hypotheses of the nature and function of AP in N. pilipes by staging mating trials with varying degrees of polyandry. No APs were ever formed during mating trials, which rules out the possibility of male AP formation. Instead, those females that oviposited produced the AP from a liquid secreted during egg sac formation. Polyandrous females were more likely to lay eggs and to produce the AP, as were those that mated longer and with more total insertions. Our further tests revealed that, in spite of being a side product of egg sac production, AP, when hardened, prevented any subsequent copulation. Conclusions We conclude that in the giant wood spider (Nephila pilipes), the amorphous mating plugs are not produced by the males, that repeated copulations (most likely polyandrous) are necessary for egg fertilization and AP formation, and that the AP represents a female adaptation to sexual conflict through prevention of unwanted, excessive copulations. Considering the largely unknown origin of amorphous plugs in spiders, we predict that a similar pattern might be detected in other clades, which would help elucidate the evolutionary interplay of various selection pressures responsible for the origin and maintenance of mating plugs. PMID:22829900

Rapid fibrin plug formation within cutaneous ablative fractional CO2 laser lesions.

PubMed

Kositratna, Garuna; Evers, Michael; Sajjadi, Amir; Manstein, Dieter

2016-02-01

Ablative fractional laser procedures have been shown to facilitate topical drug delivery into the skin. Past studies have mainly used ex vivo models to demonstrate enhanced drug delivery and in vivo studies have investigated laser created channels over a time course of days and weeks rather than within the first few minutes and hours after exposures. We have noticed rapid in vivo fibrin plug formation within ablative fractional laser lesions impairing passage through the laser created channels. In vivo laser exposures were performed in a porcine model. A fractional CO2 laser (AcuPulse™ system, AcuScan 120™ handpiece, Lumenis, Inc., Yokneam, Israel) was programmed in quasi-continuous wave (QCW) mode, at 40W, 50 mJ per pulse, 5% coverage, nominal 120 µm spot size, 8 × 8 mm square pattern, 169 MTZs per scan. Six millimeters punch biopsies were procured at 0, 2, 5, 10, 15, 30, 60, 90 minutes after completion of each scan, then fixed in 10% formalin. 12 repeats were performed of each time point. Skin samples were processed for serial vertically cut paraffin sections (5 μm collected every 25 μm) then H&E and special immunohistochemistry staining for fibrin and platelet. Dimensions of Microscopic Treatment Zones (MTZs) and extent of fibrin plug were assessed and quantified histologically. Ex vivo laser exposures of the identical laser parameter were performed on porcine and human skin at different storage conditions. Histology procured at various predetermined time intervals after in vivo fractional CO2 laser exposures revealed a rapidly forming fibrin plug initiating at the bottom of the MTZ lesions. At longer time intervals, the fibrin plug was extending towards the superficial sections. Within the first 5 minutes, more than 25% length of the entire laser-ablated channel was filled with a fibrin plug. With increased time intervals, the cavity was progressively filled with a fibrin plug. At 90 minutes, more than 90% length of the entire laser-ablated channel was occluded. Ex vivo exposures failed to produce any significant fibrin plug formation. The current study has demonstrated rapid fibrin plug formation after ablative fractional laser procedures. It was shown that the passage through laser created pathways is critically time dependent for in vivo exposures. In contrast, ex vivo exposures do not exhibit such time dependent passage capacity. In particular, drug, substance, and cell delivery studies for ablative fractional laser treatments should take early fibrin plug formation into consideration and further investigate the impact on transdermal delivery. © 2015 Wiley Periodicals, Inc.

On-Chip Titration of an Anticoagulant Argatroban and Determination of the Clotting Time within Whole Blood or Plasma Using a Plug-Based Microfluidic System

PubMed Central

Song, Helen; Li, Hung-Wing; Munson, Matthew S.; Van Ha, Thuong G.; Ismagilov, Rustem F.

2006-01-01

This paper describes extending plug-based microfluidics to handling complex biological fluids such as blood, solving the problem of injecting additional reagents into plugs, and applying this system to measuring of clotting time in small volumes of whole blood and plasma. Plugs are droplets transported through microchannels by fluorocarbon fluids. A plug-based microfluidic system was developed to titrate an anticoagulant (argatroban) into blood samples and to measure the clotting time using the activated partial thromboplastin time (APTT) test. To carry out these experiments, the following techniques were developed for a plug-based system: (i) using Teflon AF coating on the microchannel wall to enable formation of plugs containing blood and transport of the solid fibrin clots within plugs, (ii) using a hydrophilic glass capillary to enable reliable merging of a reagent from an aqueous stream into plugs, (iii) using bright-field microscopy to detect the formation of a fibrin clot within plugs and using fluorescent microscopy to detect the production of thrombin using a fluorogenic substrate, and (iv) titration of argatroban (0–1.5 μg/mL) into plugs and measurement of the resulting APTTs at room temperature (23 °C) and physiological temperature (37 °C). APTT measurements were conducted with normal pooled plasma (platelet-poor plasma) and with donor’s blood samples (both whole blood and platelet-rich plasma). APTT values and APTT ratios measured by the plug-based microfluidic device were compared to the results from a clinical laboratory at 37 °C. APTT obtained from the on-chip assay were about double those from the clinical laboratory but the APTT ratios from these two methods agreed well with each other. PMID:16841902

Research on ultrasonic excitation for the removal of drilling fluid plug, paraffin deposition plug, polymer plug and inorganic scale plug for near-well ultrasonic processing technology.

PubMed

Wang, Zhenjun; Zeng, Jing; Song, Hao; Li, Feng

2017-05-01

Near-well ultrasonic processing technology attracts more attention due to its simple operation, high adaptability, low cost and no pollution to the formation. Although this technology has been investigated in detail through laboratory experiments and field tests, systematic and intensive researches are absent for certain major aspects, such as whether ultrasonic excitation is better than chemical agent for any plugs removal; whether ultrasound-chemical combination plug removal technology has the best plugs removal effect. In this paper, the comparison of removing drilling fluid plug, paraffin deposition plug, polymer plug and inorganic scale plug using ultrasonic excitation, chemical agent and ultrasound-chemical combination plug removal technology is investigated. Results show that the initial core permeability and ultrasonic frequency play a significant role in plug removal. Ultrasonic excitation and chemical agent have different impact on different plugs. The comparison results show that the effect of removing any plugs using ultrasound-chemicals composite plug removal technology is obviously better than that using ultrasonic excitation or chemical agent alone. Such conclusion proves that ultrasonic excitation and chemical agent can cause synergetic effects. Copyright © 2016 Elsevier B.V. All rights reserved.

Geology and geologic history of the Moscow-Pullman basin, Idaho and Washington, from late Grande Ronde to late Saddle Mountains time

USGS Publications Warehouse

Bush, John H; Garwood, Dean L; Dunlap, Pamela

2016-01-01

The Moscow-Pullman basin, located on the eastern margin of the Columbia River flood basalt province, consists of a subsurface mosaic of interlayered Miocene sediments and lava flows of the Imnaha, Grande Ronde, Wanapum, and Saddle Mountains Basalts of the Columbia River Basalt Group. This sequence is ~1800 ft (550 m) thick in the east around Moscow, Idaho, and exceeds 2300 ft (700 m) in the west at Pullman, Washington. Most flows entered from the west into a topographic low, partially surrounded by steep mountainous terrain. These flows caused a rapid rise in base level and deposition of immature sediments. This field guide focuses on the upper Grande Ronde Basalt, Wanapum Basalt, and sediments of the Latah Formation.Late Grande Ronde flows terminated midway into the basin to begin the formation of a topographic high that now separates a thick sediment wedge of the Vantage Member to the east of the high from a thin layer to the west. Disrupted by lava flows, streams were pushed from a west-flowing direction to a north-northwest orientation and drained the basin through a gap between steptoes toward Palouse, Washington. Emplacement of the Roza flow of the Wanapum Basalt against the western side of the topographic high was instrumental in this process, plugging west-flowing drainages and increasing deposition of Vantage sediments east of the high. The overlying basalt of Lolo covered both the Roza flow and Vantage sediments, blocking all drainages, and was in turn covered by sediments interlayered with local Saddle Mountains Basalt flows. Reestablishment of west-flowing drainages has been slow.The uppermost Grande Ronde, the Vantage, and the Wanapum contain what is known as the upper aquifer. The water supply is controlled, in part, by thickness, composition, and distribution of the Vantage sediments. A buried channel of the Vantage likely connects the upper aquifer to Palouse, Washington, outside the basin. This field guide locates outcrops; relates them to stratigraphic well data; outlines paleogeographic basin evolution from late Grande Ronde to the present time; and notes structures, basin margin differences, and features that influence upper aquifer water supply.

Salt Plug Formation Caused by Decreased River Discharge in a Multi-channel Estuary

PubMed Central

Shaha, Dinesh Chandra; Cho, Yang-Ki

2016-01-01

Freshwater input to estuaries may be greatly altered by the river barrages required to meet human needs for drinking water and irrigation and prevent salt water intrusion. Prior studies have examined the salt plugs associated with evaporation and salt outwelling from tidal salt flats in single-channel estuaries. In this work, we discovered a new type of salt plug formation in the multi-channel Pasur River Estuary (PRE) caused by decreasing river discharges resulting from an upstream barrage. The formation of a salt plug in response to changes in river discharge was investigated using a conductivity-temperature-depth (CTD) recorder during spring and neap tides in the dry and wet seasons in 2014. An exportation of saline water from the Shibsa River Estuary (SRE) to the PRE through the Chunkhuri Channel occurred during the dry season, and a salt plug was created and persisted from December to June near Chalna in the PRE. A discharge-induced, relatively high water level in the PRE during the wet season exerted hydrostatic pressure towards the SRE from the PRE and thereby prevented the intrusion of salt water from the SRE to the PRE. PMID:27255892

Catastrophic valley fills record large Himalayan earthquakes, Pokhara, Nepal

NASA Astrophysics Data System (ADS)

Stolle, Amelie; Bernhardt, Anne; Schwanghart, Wolfgang; Hoelzmann, Philipp; Adhikari, Basanta R.; Fort, Monique; Korup, Oliver

2017-12-01

Uncertain timing and magnitudes of past mega-earthquakes continue to confound seismic risk appraisals in the Himalayas. Telltale traces of surface ruptures are rare, while fault trenches document several events at best, so that additional proxies of strong ground motion are needed to complement the paleoseismological record. We study Nepal's Pokhara basin, which has the largest and most extensively dated archive of earthquake-triggered valley fills in the Himalayas. These sediments form a 148-km2 fan that issues from the steep Seti Khola gorge in the Annapurna Massif, invading and plugging 15 tributary valleys with tens of meters of debris, and impounding several lakes. Nearly a dozen new radiocarbon ages corroborate at least three episodes of catastrophic sedimentation on the fan between ∼700 and ∼1700 AD, coinciding with great earthquakes in ∼1100, 1255, and 1344 AD, and emplacing roughly >5 km3 of debris that forms the Pokhara Formation. We offer a first systematic sedimentological study of this formation, revealing four lithofacies characterized by thick sequences of mid-fan fluvial conglomerates, debris-flow beds, and fan-marginal slackwater deposits. New geochemical provenance analyses reveal that these upstream dipping deposits of Higher Himalayan origin contain lenses of locally derived river clasts that mark time gaps between at least three major sediment pulses that buried different parts of the fan. The spatial pattern of 14C dates across the fan and the provenance data are key to distinguishing these individual sediment pulses, as these are not evident from their sedimentology alone. Our study demonstrates how geomorphic and sedimentary evidence of catastrophic valley infill can help to independently verify and augment paleoseismological fault-trench records of great Himalayan earthquakes, while offering unparalleled insights into their long-term geomorphic impacts on major drainage basins.

A Polymer Plugging Gel for the Fractured Strata and Its Application

PubMed Central

Fan, Xiangyu; Zhao, Pengfei; Zhang, Qiangui; Zhang, Ting; Zhu, Kui; Zhou, Chenghua

2018-01-01

Well leakage of fractured strata is a tricky problem while drilling. This unwieldy problem is usually caused by the poor formation of the cementing degree, the staggered-mesh of the fracture, and the low bearing capacity of the formation, which can also lead to a narrow and even unsafe window of drilling fluid density. For fractured strata, the normal plugging material has the disadvantages of unsuitable size and low strength, resulting in unsuccessful first time plugging and an increase in cost. Therefore, we developed a polymer plugging gel for the fractured strata, named XNGJ-3. XNGJ-3 is mainly made of an acrylamide monomer and is accompanied by the reactive monomers of carboxyl and hydroxyl as ingredients. XNGJ-3 has a low viscosity before gelling. At 80 °C it becomes gelled, and the gelling time was controlled within the required time of the practical application. These conditions are beneficial for making the plugging material enter the crossing fracture smoothly and occlude the fracture. XNGJ-3 also has a good deformability and can avoid being damaged during the process of fracture closure. The well leakage simulated experiment revealed that the bearing capacity of this material can reach 21 MPa and the inverse bearing capacity can reach 20 MPa. These strengths are more than twice that of common polymer plugging gels. Finally, three leaked wells in the fractured strata of the Sichuan Basin were used to verify the plugging effect of XNGJ-3. Compared with other common plugging materials, XNGJ-3 has the advantages of having a higher success rate of first time plugging, a lower economic cost, a shorter work time, and so forth, which indicate that this plugging material has a good engineering application value in dealing with well leakage of fractured strata. PMID:29883407

Failure investigations of failed valve plug SS410 steel due to cracking

NASA Astrophysics Data System (ADS)

Kalyankar, V. D.; Deshmukh, D. D.

2017-12-01

Premature and sudden in service failure of a valve plug due to crack formation, applied in power plant has been investigated. The plug was tempered and heat treated, the crack was originated at centre, developed along the axis and propagates radially towards outer surface of plug. The expected life of the component is 10-15 years while, the component had failed just after the installation that is, within 3 months of its service. No corrosion products were observed on the crack interface and on the failed surface; hence, causes of corrosion failure are neglected. This plug of level separator control valve, is welded to the stem by means of plasma-transferred arc welding and as there is no crack observed at the welding zone, the failure due to welding residual stresses are also neglected. The failed component discloses exposed surface of a crack interface that originated from centre and propagates radially. The micro-structural observation, hardness testing, and visual observation are carried out of the specimen prepared from the failed section and base portion. The microstructure from the cracked interface showed severe carbide formation along the grain boundaries. From the microstructural analysis of the failed sample, it is observed that there is a formation of acicular carbides along the grain boundaries due to improper tempering heat treatment.

HOW DO STONES FORM? IS UNIFICATION OF THEORIES ON STONE FORMATION POSSIBLE?

PubMed Central

Bird, Victoria Y.; Khan, Saeed R.

2017-01-01

Summary There are two basic pathways for formation of calcium based kidney stones. Most idiopathic calcium oxalate (CaOx) stones are formed in association with sub-epithelial plaques of calcium phosphate (CaP), known as Randall’s plaques, on renal papillary surfaces. Crystal formation and retention within the terminal collecting ducts, the ducts of Bellini, leading to the formation of Randall’s plugs, is the other pathway. Both pathways require supersaturation leading to crystallization, regulated by various crystallization modulators produced in response to changing urinary conditions. High supersaturation, as a result of a variety of genetic and environmental factors, leads to crystallization in the terminal collecting ducts, eventually plugging their openings into the renal pelvis. Stasis behind the plugs may lead to the formation of attached or unattached stones in the tubular lumen. Deposition of crystals on the plug surface facing the pelvic or tubular urine may result in stone formation on the Randall’s plugs. Kidneys of idiopathic stone formers may be subjected to oxidative stress as a result of increased urinary excretion of calcium/oxalate/phosphate and/or decrease in the production of functional crystallization inhibitors or in relation to co-morbidities such as hypertension, atherosclerosis, or acute kidney injury. We have proposed that production of reactive oxygen species (ROS) causes dedifferentiation of epithelial/endothelial cells into osteoblast type cells and deposition of CaP in the basement membrane of renal tubules or vessels. Growth, aggregation and melding of CaP crystals leads to the formation of plaque which grows by further calcification of interstitial collagen and membranous vesicles. Plaque becomes exposed to pelvic urine once the covering papillary epithelium is breached. Surface layers of CaP are replaced by CaOx through direct transformation or demineralization of CaP and mineralization of CaOx. Alternatively, or in addition, CaOx crystals nucleate directly on the plaque surface. Stone growth may also depend upon supersaturation in the pelvic urine, triggering further nucleation, growth and aggregation. PMID:28221139

Evaluation of flushing of a high-selenium backwater channel in the Colorado River.

PubMed

Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A; Weston, L Ken; McDonald, Susan F

2004-02-01

Concern has been raised that selenium contamination may be adversely affecting endangered fish in the upper Colorado River basin. The objective of the study was to determine if operation of a water control structure (opened in December 1996) that allowed the Colorado River to flow through a channel area at Walter Walker State Wildlife Area (WWSWA) would reduce selenium and other inorganic elements in water, sediment, aquatic invertebrates, and forage fish. Endangered Colorado pikeminnow were collected and muscle plug samples taken for selenium analysis. Selenium concentrations in filtered water were 21.0 microg/L in 1995, 23.5 microg/L in 1996, 2.1 microg/L in 1997, and 2.1 microg/L in 1998. Selenium concentrations in sediment cores and sediment traps were 8.5 microg/g in 1995, 8.2 microg/g in 1996, 4.8 microg/g in 1997, and 1.1 microg/g in 1998. Selenium concentrations in aquatic invertebrates were 27.4 microg/g in 1996, 15.5 microg/g in 1997, and 4.9 microg/g in 1998. Selenium concentrations in forage fish were 27.2 microg/g in 1996, 20.2 microg/g in 1997, and 8.6 microg/g in 1998. Selenium concentrations in muscle plugs of Colorado pikeminnow were 9.8 microg/g in 1995, 9.5 microg/g in 1996, 9.0 microg/g in 1997, and 10.3 microg/g in 1998. Although selenium concentrations in water, sediment, aquatic invertebrates, and forage fish decreased substantially after operation of the water control structure, a corresponding change in Colorado pikeminnow did not seem to occur. Selenium concentrations in muscle plugs decreased with increasing fish total length and weight, did not change between repeat sampling in the same year or recapture in subsequent years, and seemed to be most closely associated with the mean monthly river flow for the March-July period. Copyright 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 51-81, 2004.

Numerical simulation of water and sand blowouts when penetrating through shallow water flow formations in deep water drilling

NASA Astrophysics Data System (ADS)

Ren, Shaoran; Liu, Yanmin; Gong, Zhiwu; Yuan, Yujie; Yu, Lu; Wang, Yanyong; Xu, Yan; Deng, Junyu

2018-02-01

In this study, we applied a two-phase flow model to simulate water and sand blowout processes when penetrating shallow water flow (SWF) formations during deepwater drilling. We define `sand' as a pseudo-component with high density and viscosity, which can begin to flow with water when a critical pressure difference is attained. We calculated the water and sand blowout rates and analyzed the influencing factors from them, including overpressure of the SWF formation, as well as its zone size, porosity and permeability, and drilling speed (penetration rate). The obtained data can be used for the quantitative assessment of the potential severity of SWF hazards. The results indicate that overpressure of the SWF formation and its zone size have significant effects on SWF blowout. A 10% increase in the SWF formation overpressure can result in a more than 90% increase in the cumulative water blowout and a 150% increase in the sand blowout when a typical SWF sediment is drilled. Along with the conventional methods of well flow and pressure control, chemical plugging, and the application of multi-layer casing, water and sand blowouts can be effectively reduced by increasing the penetration rate. As such, increasing the penetration rate can be a useful measure for controlling SWF hazards during deepwater drilling.

Water and Wastewater Characterization Survey, Williams AFB AZ

DTIC Science & Technology

1991-03-01

effluent discharges. Most industrial effluent originates from the flight line operations. The WWTP includes primary sedimentation , trickling filters...final sedimentation , plug-flow chlorine contact basin, and a stabilization pond. Samples were collected at the influent and effluent of the plant...Stispcndcd Solido ~ 60) 31 pit wvithll 6.0 to 90- *1 1*0 is Totil toxic 0, plan:*’ aq (leCiitc(l at .i10 (1 R Pitt 4133. 5 (IIIL)RINE REOPENEP T1 his permit

LST CGM Generator and Viewer Final Report CRADA No. TSB-1558-98

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

Vickers, Don; Larson, Don

The purpose of this project was to jointly develop and test a software plug-in that would convert native Pro /ENGINEER digital engineering drawings to Computer Graphics Metafile (CGM) format. If it was not feasible to convert the Pro/ENGINEER files, we planned to develop and test a similar conversion of native AutoCAD engineering drawings to CGM. CGM viewer plug-ins were developed as needed. There were four main tasks in this project: 1. Requirements for CGM Plug-in 2. Product Evaluation 3. Product Development Feasibility Study 4. Developing a "Plug-In" Application.

Molten tin reprocessing of spent nuclear fuel elements

DOEpatents

Heckman, Richard A.

1983-01-01

A method and apparatus for reprocessing spent nuclear fuel is described. Within a containment vessel, a solid plug of tin and nitride precipitates supports a circulating bath of liquid tin therein. Spent nuclear fuel is immersed in the liquid tin under an atmosphere of nitrogen, resulting in the formation of nitride precipitates. The layer of liquid tin and nitride precipitates which interfaces the plug is solidified and integrated with the plug. Part of the plug is melted, removing nitride precipitates from the containment vessel, while a portion of the plug remains solidified to support the liquid tin and nitride precipitates remaining in the containment vessel. The process is practiced numerous times until substantially all of the precipitated nitrides are removed from the containment vessel.

Instability-induced ordering, universal unfolding and the role of gravity in granular Couette flow

NASA Astrophysics Data System (ADS)

Alam, Meheboob; Arakeri, V. H.; Nott, P. R.; Goddard, J. D.; Herrmann, H. J.

2005-01-01

Linear stability theory and bifurcation analysis are used to investigate the role of gravity in shear-band formation in granular Couette flow, considering a kinetic-theory rheological model. We show that the only possible state, at low shear rates, corresponds to a "plug" near the bottom wall, in which the particles are densely packed and the shear rate is close to zero, and a uniformly sheared dilute region above it. The origin of such plugged states is shown to be tied to the spontaneous symmetry-breaking instabilities of the gravity-free uniform shear flow, leading to the formation of ordered bands of alternating dilute and dense regions in the transverse direction, via an infinite hierarchy of pitchfork bifurcations. Gravity plays the role of an "imperfection", thus destroying the "perfect" bifurcation structure of uniform shear. The present bifurcation problem admits universal unfolding of pitchfork bifurcations which subsequently leads to the formation of a sequence of a countably infinite number of "isolas", with the solution structures being a modulated version of their gravity-free counterpart. While the solution with a plug near the bottom wall looks remarkably similar to the shear-banding phenomenon in dense slow granular Couette flows, a "floating" plug near the top wall is also a solution of these equations at high shear rates. A two-dimensional linear stability analysis suggests that these floating plugged states are unstable to long-wave travelling disturbances.The unique solution having a bottom plug can also be unstable to long waves, but remains stable at sufficiently low shear rates. The implications and realizability of the present results are discussed in the light of shear-cell experiments under "microgravity" conditions.

Twenty Years of "Plug-and-Pond" Meadow Restoration: A Geomorphic Review

NASA Astrophysics Data System (ADS)

Natali, J.

2015-12-01

Channel incision has degraded the ecological function of wet meadows across montane regions of California. Conservation groups estimate that half of the Sierra Nevada's 333,000 acres of meadow are entrenched in a degraded state that is characterized by a shift from groundwater­fed, herbaceous vegetation to more sparse, drought­tolerant woody vegetation. My poster will present results of field research on a prominent restoration technique in California's montane meadows, the "Plug­and­Pond." Fundamentally, the technique re­channelizes the meadow by blocking flow into incised stream channels. Spoils dug from meadow sediments plug the incised channel, creating ponds as a by­product. One of three approaches to re­channelization ensues: (1) construct a new shallow and sinuous channel, (2) redirect flows into a remnant channel, (3) or allow the channel to define itself over the meadow floodplain. Re­ channelization aims to support overbank flows at 1.5 to 3 year recurrence intervals. Field surveys of ten of the oldest "plug-and-pond" meadow restoration projects in California reveal that channel bed degradation caused by meadow-scale changes to channel slope (i.e. culverts concentrating flows, channel straightening, meadow grazing) may be more conducive to intensive restoration approaches like Plug-and-Pond.

Molten tin reprocessing of spent nuclear fuel elements. [Patent application; continuous process

DOEpatents

Heckman, R.A.

1980-12-19

A method and apparatus for reprocessing spent nuclear fuel is described. Within a containment vessel, a solid plug of tin and nitride precipitates supports a circulating bath of liquid tin therein. Spent nuclear fuel is immersed in the liquid tin under an atmosphere of nitrogen, resulting in the formation of nitride precipitates. The layer of liquid tin and nitride precipitates which interfaces the plug is solidified and integrated with the plug. Part of the plug is melted, removing nitride precipitates from the containment vessel, while a portion of the plug remains solidified to support te liquid tin and nitride precipitates remaining in the containment vessel. The process is practiced numerous times until substantially all of the precipitated nitrides are removed from the containment vessel.

Aerial mulching techniques-trough fire

Treesearch

Robert Faust

2008-01-01

The Trough fire occurred in August 2001 on the Mendocino National Forest of northern California. A burned area emergency rehabilitation team evaluated the fire effects on the watershed. Concerns were soil from the denuded slopes moving into streams affecting fishery values, reservoir sedimentation and storm runoff plugging culverts leading to road wash outs. Past...

Bubble-free on-chip continuous-flow polymerase chain reaction: concept and application.

PubMed

Wu, Wenming; Kang, Kyung-Tae; Lee, Nae Yoon

2011-06-07

Bubble formation inside a microscale channel is a significant problem in general microfluidic experiments. The problem becomes especially crucial when performing a polymerase chain reaction (PCR) on a chip which is subject to repetitive temperature changes. In this paper, we propose a bubble-free sample injection scheme applicable for continuous-flow PCR inside a glass/PDMS hybrid microfluidic chip, and attempt to provide a theoretical basis concerning bubble formation and elimination. Highly viscous paraffin oil plugs are employed in both the anterior and posterior ends of a sample plug, completely encapsulating the sample and eliminating possible nucleation sites for bubbles. In this way, internal channel pressure is increased, and vaporization of the sample is prevented, suppressing bubble formation. Use of an oil plug in the posterior end of the sample plug aids in maintaining a stable flow of a sample at a constant rate inside a heated microchannel throughout the entire reaction, as compared to using an air plug. By adopting the proposed sample injection scheme, we demonstrate various practical applications. On-chip continuous-flow PCR is performed employing genomic DNA extracted from a clinical single hair root sample, and its D1S80 locus is successfully amplified. Also, chip reusability is assessed using a plasmid vector. A single chip is used up to 10 times repeatedly without being destroyed, maintaining almost equal intensities of the resulting amplicons after each run, ensuring the reliability and reproducibility of the proposed sample injection scheme. In addition, the use of a commercially-available and highly cost-effective hot plate as a potential candidate for the heating source is investigated.

Sediment mineralogy based on visible and near-infrared reflectance spectroscopy

USGS Publications Warehouse

Jarrard, R.D.; Vanden Berg, M.D.; ,

2006-01-01

Visible and near-infrared spectroscopy (VNIS) can be used to measure reflectance spectra (wavelength 350-2500 nm) for sediment cores and samples. A local ground-truth calibration of spectral features to mineral percentages is calculated by measuring reflectance spectra for a suite of samples of known mineralogy. This approach has been tested on powders, core plugs and split cores, and we conclude that it works well on all three, unless pore water is present. Initial VNIS studies have concentrated on determination of relative proportions of carbonate, opal, smectite and illite in equatorial Pacific sediments. Shipboard VNIS-based determination of these four components was demonstrated on Ocean Drilling Program Leg 199. ?? The Geological Society of London 2006.

Temporary plugging agent

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

Black, H.N.; Melton, L.L.

1966-01-04

A temporary plugging agent, fracturing fluid and/or channel sealing agent is introduced into a selected area of a formation. The water-gelled fluid agent contains sodium borate, sodium tetraborate, and borax. It also contains a chemical breaker such as benzotrichloride, benzylidene chloride, or benzyl chloride. The water-gelled fluid consists essentially of water and from about 1-3% by weight of water of a finely powdered water-soluble gum of the galactomannan class. The borate compound is included in an amount of about 10% by weight of the gum to delay the reaction with the gel and to form a rubbery jelly-like mass withmore » it. The fluid composition has a delaying solidifying action and after a given interval of time it forms a plug. After a predetermined time, acid is produced upon the hydrolysis of the breaker in the plug and removes the plug from the area.« less

An Investigation of the Cryogenic Freezing of Water in Non-Metallic Pipelines

NASA Astrophysics Data System (ADS)

Martin, C. I.; Richardson, R. N.; Bowen, R. J.

2004-06-01

Pipe freezing is increasingly used in a range of industries to solve otherwise intractable pipe line maintenance and servicing problems. This paper presents the interim results from an experimental study on deliberate freezing of polymeric pipelines. Previous and contemporary works are reviewed. The object of the current research is to confirm the feasibility of ice plug formation within a polymeric pipe as a method of isolation. Tests have been conducted on a range of polymeric pipes of various sizes. The results reported here all relate to freezing of horizontal pipelines. In each case the process of plug formation was photographed, the frozen plug pressure tested and the pipe inspected for signs of damage resulting from the freeze procedure. The time to freeze was recorded and various temperatures logged. These tests have demonstrated that despite the poor thermal and mechanical properties of the polymers, freezing offers a viable alternative method of isolation in polymeric pipelines.

Using simple structures for flow dispersion in wet meadow restoration

Treesearch

Bill Zeedyk; Benjamin Romero; Steven K. Albert

1996-01-01

Historically, wet meadow recovery projects have relied on heavy earth moving equipment to harden nick points and install gully plugs or terraces to trap and detain sediments. We experimented with a variety of simple hand-built structures fashioned of logs, rocks, geotextile fabrics and/or sandbags designed to disperse runoff, rewet surface and subsurface soils and...

Selenium concentrations in the Colorado pikeminnow (Ptychocheilus lucius): Relationship with flows in the upper Colorado River

USGS Publications Warehouse

Osmundson, B.C.; May, T.W.; Osmundson, D.B.

2000-01-01

A Department of the Interior (DOI) irrigation drainwater study of the Uncompahgre Project area and the Grand Valley in western Colorado revealed high selenium concentrations in water, sediment, and biota samples. The lower Gunnison River and the Colorado River in the study area are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus). Because of the endangered status of these fish, sacrificing individuals for tissue residue analysis has been avoided; consequently, little information existed regarding selenium tissue residues. In 1994, muscle plugs were collected from a total of 39 Colorado pikeminnow captured at various Colorado River sites in the Grand Valley for selenium residue analysis. The muscle plugs collected from 16 Colorado pikeminnow captured at Walter Walker State Wildlife Area (WWSWA) contained a mean selenium concentration of 17 ??g/g dry weight, which was over twice the recommended toxic threshold guideline concentration of 8 ??g/g dry weight in muscle tissue for freshwater fish. Because of elevated selenium concentrations in muscle plugs in 1994, a total of 52 muscle plugs were taken during 1995 from Colorado pikeminnow staging at WWSWA. Eleven of these plugs were from fish previously sampled in 1994. Selenium concentrations in 9 of the 11 recaptured fish were significantly lower in 1995 than in 1994. Reduced selenium in fish may in part be attributed to higher instream flows in 1995 and lower water selenium concentrations in the Colorado River in the Grand Valley. In 1996, muscle plugs were taken from 35 Colorado squawfish captured at WWSWA, and no difference in mean selenium concentrations were detected from those sampled in 1995. Colorado River flows during 1996 were intermediate to those measured in 1994 and 1995.

Selenium concentrations in the Colorado pikeminnow (Ptychocheilus lucius): relationship with flows in the upper Colorado River.

PubMed

Osmundson, B C; May, T W; Osmundson, D B

2000-05-01

A Department of the Interior (DOI) irrigation drainwater study of the Uncompahgre Project area and the Grand Valley in western Colorado revealed high selenium concentrations in water, sediment, and biota samples. The lower Gunnison River and the Colorado River in the study area are designated critical habitat for the endangered Colorado pikeminnow (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus). Because of the endangered status of these fish, sacrificing individuals for tissue residue analysis has been avoided; consequently, little information existed regarding selenium tissue residues. In 1994, muscle plugs were collected from a total of 39 Colorado pikeminnow captured at various Colorado River sites in the Grand Valley for selenium residue analysis. The muscle plugs collected from 16 Colorado pikeminnow captured at Walter Walker State Wildlife Area (WWSWA) contained a mean selenium concentration of 17 microg/g dry weight, which was over twice the recommended toxic threshold guideline concentration of 8 microg/g dry weight in muscle tissue for freshwater fish. Because of elevated selenium concentrations in muscle plugs in 1994, a total of 52 muscle plugs were taken during 1995 from Colorado pikeminnow staging at WWSWA. Eleven of these plugs were from fish previously sampled in 1994. Selenium concentrations in 9 of the 11 recaptured fish were significantly lower in 1995 than in 1994. Reduced selenium in fish may in part be attributed to higher instream flows in 1995 and lower water selenium concentrations in the Colorado River in the Grand Valley. In 1996, muscle plugs were taken from 35 Colorado squawfish captured at WWSWA, and no difference in mean selenium concentrations were detected from those sampled in 1995. Colorado River flows during 1996 were intermediate to those measured in 1994 and 1995.

Experimental and theoretical investigation of the role of clay in subaqueous sediment flows and its effect on run-out distance

NASA Astrophysics Data System (ADS)

Hermidas, Navid; Luthi, Stefan; Eggenhuisen, Joris; Silva Jacinto, Ricardo; Toth, Ferenc; Pohl, Florian; de Leeuw, Jan

2016-04-01

Debris flows are driven by gravity, which in the tail region is overcome by the yield strength of the flow, forcing it to freeze. These flows are capable of achieving staggeringly large run-out distances on low gradients. The case in point, described in previous publications, is the flow which resulted in the deposit of Bed 5 of the Agadir megaslide on the north-west African margin. Debrites of this flow have been recorded several hundred kilometres away from the original landslide. Previous studies have attributed such long run-out distances to hydroplaning, low yield strength, and flow transformation. It is known that the net force acting on a volume of fluid in equilibrium is zero. In this work we show that clay-laden flows are capable of approaching equilibrium. The flows which can achieve the maximum run-out distance are cohesive enough to resist some of the surrounding disturbances, that can upset the equilibrium, and reach close to equilibrium conditions, yet are dilute enough to have low viscous stress, and relatively low yield strength and lose little sediment due to deposition. A flow that is not in equilibrium will always seek to approach equilibrium conditions by speeding up or slowing down, depositing sediment, eroding the substrate, contracting in the form of the tail approaching the head, stretching, entraining water and growing in height, or dewatering and collapsing. Here we present a theory that shows that two dimensional (2D) flows in equilibrium do not grow in height. 2D flume experiments were conducted on different mixtures of kaolinite, sand, silt, and water, on varying slopes and a transitionally rough bed (sand glued), and using various discharge rates, in order to map out different stages in the evolution of a density flow from a cohesive plug flow into a turbidity current. The following flow types were observed: high density turbidity currents, plug flows, and no flow. From the velocity profiles, certain runs demonstrated close to equilibrium behaviour. For these flows, very little flow height growth and velocity variation was observed over the length of the flume. In all cases the flow appeared to be laminar within the boundary layer with Kelvin-Helmholtz instabilities at the top which were suppressed to a large extent for higher sediment concentrations. A deposit consisting of thick muddy sand, with approximately uniform thickness, was observed for higher sediment concentrations, indicating relatively higher yield strength values, while a thinner more sandy deposit was observed for more dilute flows. It was concluded that high sediment concentrations on more moderate slopes result in slower moving plug flows which are capable of suppressing turbulence at the top, while lower sediment concentrations on steeper slopes result in faster moving, more turbulent currents. The flows which can achieve the largest run-out distance are located between these two extremes.

Biodegradable microfabricated plug-filters for glaucoma drainage devices.

PubMed

Maleki, Teimour; Chitnis, Girish; Park, Jun Hyeong; Cantor, Louis B; Ziaie, Babak

2012-06-01

We report on the development of a batch fabricated biodegradable truncated-cone-shaped plug filter to overcome the postoperative hypotony in nonvalved glaucoma drainage devices. Plug filters are composed of biodegradable polymers that disappear once wound healing and bleb formation has progressed past the stage where hypotony from overfiltration may cause complications in the human eye. The biodegradable nature of device eliminates the risks associated with permanent valves that may become blocked or influence the aqueous fluid flow rate in the long term. The plug-filter geometry simplifies its integration with commercial shunts. Aqueous humor outflow regulation is achieved by controlling the diameter of a laser-drilled through-hole. The batch compatible fabrication involves a modified SU-8 molding to achieve truncated-cone-shaped pillars, polydimethylsiloxane micromolding, and hot embossing of biodegradable polymers. The developed plug filter is 500 μm long with base and apex plane diameters of 500 and 300 μm, respectively, and incorporates a laser-drilled through-hole with 44-μm effective diameter in the center.

A New Late Glacial Site in the Central Appalachians of Virginia. Preliminary Findings From Paleobotany, Palynology, and Geomorphology

NASA Astrophysics Data System (ADS)

Schwartz, B. F.; Upchurch, G. R.; Willard, D. A.; Bernhardt, C. E.; Valella, P. A.

2009-12-01

Thick clay deposits in a recently identified paleo-lake bed in a central Appalachian karst system in Highland County, Virginia have yielded well-preserved pollen and macroflora that provide the opportunity to refine the understanding of Pleistocene climate, vegetation dynamics, and erosion in the region. A radiocarbon date of 22,000 14C yr B.P. on wood fragments near the top of the sequence establishes the age of the sediments. Pollen and plant macrofloras characteristic of modern boreal forests are present in sediments at this site. Pollen assemblages show a dominance of conifers, mostly Pinus banksiana and Picea, with Lycopodium as important ground cover. Leaf fossils sieved from the clay show a dominance of Picea needles and common dicot leaf fragments, suggesting that Pinus is either over-represented in the pollen flora or more distal to the paleo-lake. Macrofossil assemblages sieved from the clay contain a variety of non-leaf remains, including fruits, seeds, mosses, insects, feathers, and fungi. Test augering and geophysical results indicate that these clay deposits are at least 9m and perhaps as much as 15m thick. The amount and temporal distribution of sediment loads to the paleo-lake (a depositional environment) from the surrounding landscape (an erosional environment) will be modeled using analysis of sediment facies in and above (>12m) these clays, combined with sediment volume calculations and drainage basin analysis, and constrained by dates from the sediments themselves. Due to the rare occurrence of still-water depositional environments in the Appalachians, this site provides paleo-climate and sedimentological data that will refine regional models of landscape evolution and incision. This work also has implications for the development and modification of a significant karst system that surrounds and underlies the paleo-lake bed. The same karst system is responsible both for the formation of the paleo-lake (after the drain in a blind valley became plugged), and its later draining and current removal of lake sediments through the underlying karst system.

Study of Plasma Behavior during ECRH Injection in the GAMMA 10 SMBI Experiments

NASA Astrophysics Data System (ADS)

Maidul Islam, Md.; Nakashima, Yousuke; Kobayashi, Shinji; Nishino, Nobuhiro; Ichimura, Kazuya; Iijima, Takaaki; Shahinul Islam, Md.; Yokodo, Takayuki; Lee, Guanyi; Yoshimoto, Tsubasa; Yamashita, Sotaro; Yoshikawa, Masayuki; Kohagura, Junko; Hirata, Mafumi; Minami, Ryutaro; Kariya, Tsuyoshi; Ikezoe, Ryuya; Ichimura, Makoto; Sakamoto, Mizuki; Imai, Tsuyoshi

2018-01-01

Establishment of fueling system is one of the critical issues for the future fusion reactors. Fueling experiment supersonic molecular beam injection (SMBI) have been carried out in the central-cell of GAMMA 10. In GAMMA 10, electron cyclotron resonance heating (ECRH) is used at plug/barrier-cells for the formation of the axial confining potential. Recently, ECRH was applied during SMBI to plug the loss particles and increased the plasma density in the central-cell compared to without ECRH. This result suggests that the particles are confined during SMBI due to the injection of ECRH at plug/barrier-cells in GAMMA 10.

Revascularization and Apical Plug in an Immature Molar

PubMed Central

Roghanizadeh, Leyla; Fazlyab, Mahta

2018-01-01

Managing of necrotic permanent teeth with immature apices is a treatment challenges. Treatment of such teeth includes apexification, apical plug and more recently, revascularization technique with the probable advantage of continuation of root development. In the present case report the referred patient had discomfort with a necrotic immature mandibular first molar. Periapical radiography showed a rather large apical lesion around immature roots. Revascularization protocol using calcium-enriched mixture (CEM) cement was indicated for the mesial root. However, in distal canal apical plug technique was applied. At 2-year follow-up, both procedures were successful in relieving patient’s symptoms. Dentin formation and increase in length of the mesial root was obvious. Apical plug and revascularization technique proved to be successful in management of necrotic immature teeth; moreover, revascularization carried the advantage of continuation of root development. PMID:29692851

Method for rigless zone abandonment using internally catalyzed resin system

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

Martin, R.C.

1980-02-19

A zone of a subterranean formation penetrated by a well bore is permanently plugged by injecting a liquid resin system containing at least one thermosetting resin and at least one curing agent or catalyst therefor into the formation and injecting into the wellbore following the resin system, a second liquid containing at least one chain stopping compound to react with one component in the resin system to prevent any of the resin system remaining in the well bore from crosslinking to a sufficient crosslink density to form a solid in the wellbore. Preferably, the second liquid also contains a fluidmore » loss additive to minimize loss of the second liquid from the wellbore to the formation. The method permits a zone to be plugged off and abandoned without the need to erect a drilling rig to drill out excess plugging material remaining in the wellbore. In a preferred embodiment, the resin system comprises the diglycidyl ether of bisphenol a and polymethylene phenylamine in ethylene glycol ethyl ether, and the preferred second liquid is monoethanolamine in ethylene glycol ethyl ether as a solvent with ethylcellulose and silic flour to control fluid loss.« less

Composition for preventing a resin system from setting up in a well bore

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

Martin, R. C.

1981-06-09

A zone of a subterranean formation penetrated by a well bore is permanently plugged by injecting a liquid resin system containing at least one thermosetting resin and at least one curing agent or catalyst therefor into the formation and injecting into the wellbore following the resin system, a second liquid containing at least one chain stopping compound to react with one component in the resin system to prevent any of the resin system remaining in the well bore from crosslinking to a sufficient crosslink density to form a solid in the wellbore. Preferably, the second liquid also contains a fluidmore » loss additive to minimize loss of the second liquid from the wellbore to the formation. The method permits a zone to be plugged off and abandoned without the need to erect a drilling rig to drill out excess plugging material remaining in the wellbore. In a preferred embodiment, the resin system comprises the diglycidyl ether of bisphenol a and polymethylene phenylamine in ethylene glycol ethyl ether, and the preferred second liquid is monoethanolamine in ethylene glycol ethyl ether as a solvent with ethylcellulose and silica flour to control fluid loss.« less

RCC Plug Repair Thermal Tools for Shuttle Mission Support

NASA Technical Reports Server (NTRS)

Rodriguez, Alvaro C.; Anderson, Brian P.

2010-01-01

A thermal math model for the Space Shuttle Reinforced Carbon-Carbon (RCC) Plug Repair was developed to increase the confidence in the repair entry performance and provide a real-time mission support tool. The thermal response of the plug cover plate, local RCC, and metallic attach hardware can be assessed with this model for any location on the wing leading edge. The geometry and spatial location of the thermal mesh also matches the structural mesh which allows for the direct mapping of temperature loads and computation of the thermoelastic stresses. The thermal model was correlated to a full scale plug repair radiant test. To utilize the thermal model for flight analyses, accurate predictions of protuberance heating were required. Wind tunnel testing was performed at CUBRC to characterize the heat flux in both the radial and angular directions. Due to the complexity of the implementation of the protuberance heating, an intermediate program was developed to output the heating per nodal location for all OML surfaces in SINDA format. Three Design Reference Cases (DRC) were evaluated with the correlated plug thermal math model to bound the environments which the plug repair would potentially be used.

The Role of Conjoining (Tie) Channels in Lowland Floodplain Development and Lake Infilling

NASA Astrophysics Data System (ADS)

Rowland, J. C.; Dietrich, W. E.; Day, G.; Lepper, K.; Wilson, C. J.

2003-12-01

In simple models of lowland river systems, water and sediment enter the main stem via tributary and secondary channels and are only redistributed to the floodplain during overbank and crevasse splay events. Along numerous river systems across the globe, however, water and sediment are regularly exchanged between the river and off river water bodies via stable, narrow channels. These channels, known as tie channels on the Fly River in Papua New Guinea and batture channels along the lower Mississippi, are largely overlooked but important components of floodplain sediment dispersal where they exist. These channels become pathways of sediment dispersal to the floodplain system when elevated river stages force sediment-laden flows into the off-river water bodies. On the Fly River, it is estimated that about 50% of the sediment delivery to the floodplain is via these channels, and along low gradient tributary channels during flood driven flow reversals. During low flow, tie channels serve to drain the floodplain. With the outgoing flows, large amounts sediment can be carried and lost to the floodplain; floodplain lakes progressively infill with sediment as the mouth of these channels steadily prograde lakeward. These lake deposits not only become significant stratigraphic components of floodplains (traditionally referred to as clay plugs), but are important local sinks recording hundreds to thousands of years of river history. As with all sinks, the proper interpretation of these stratigraphic records requires understanding the processes by which sediment is delivered to the sink and how these processes alter the paleohydraulic and climatic signals of interest. We have conducted field investigations of conjoining channels in Papua New Guinea (the Fly and Strickland Rivers), Louisiana (Raccourci Old River ~ 65 km upriver of Baton Rouge) and Alaska (Birch Creek). These field investigations include extensive surveys of both cross and along channel morphological trends, grain size characteristics, water levels and geochronological sampling using optically stimulated luminescence (OSL). Across all systems channel morphology is similar and exhibit scale independence, however, channel size and rates of progradation are directly related to the size of the main stem river. Through these studies and ongoing scaled modeling we are examining the morphodynamics that lead to the formation, advancement and stability of these unique self formed channels.

Extrusion cycles of dome-forming eruptions

NASA Astrophysics Data System (ADS)

de'Michieli Vitturi, M.; Clarke, A. B.; Neri, A.; Voight, B.

2010-12-01

We investigated the dynamics of magma ascent along a dome-forming conduit coupled with the formation and extrusion of a degassed plug at the top by a two-phase flow model. We treated the magma mixture as a liquid continuum with dispersed gas bubbles and crystals in thermodynamic equilibrium with the melt. A modified Poiseulle form of the viscous term for fully developed laminar flow in an elliptic conduit was assumed. During ascent, magma pressure decreases and water vapor exsolves and partially degasses from the melt as the melt simultaneously crystallizes, causing changes in mixture density and viscosity, which may eventually lead to the formation of a degassed plug sealing the conduit. The numerical model DOMEFLOW (de’ Michieli Vitturi et al., EPSL 2010) has been applied to dome-building eruptions using conditions approximately appropriate for the Soufrière Hills volcano, Montserrat, which has led to a better understanding of the role of a plug on eruption periodicity. Two mechanisms, which have been proposed to cause periodicity, have been implemented in the model and their corresponding timescales explored. The first test applies a stick-slip model in which the plug is considered as solid and static/dynamic friction, as described in Iverson et al. [Nature 2006, 444, 439-43], replaces the viscous forces in the momentum equation. This mechanism yields cycle timescales of seconds to tens of seconds with values generally depending on assumed friction coefficients. Although not all constants and parameters have been explored for this model, we suggest that a stick-slip mechanism of this type cannot explain the cycles of extrusion and explosion typically observed at Montserrat (timescales of hours). The second mechanism does not consider friction but allows enhanced permeable gas loss in the shallow conduit, possibly due to connected porosity or micro- or macro-scale fractures. Enhanced permeable gas loss may lead to formation of a dense and rheologically stiffened magma plug with high viscosity at the top of the conduit which can resist extrusion and prevent steady conduit flow. The plug produces high pressure in the upper conduit, which can cause edifice inflation. Eventually the pressure increases sufficiently to drive the degassed plug from the conduit, overcoming dome overburden, plug weight, and viscous forces. Extrusion and escape of pressurized gas result in a relaxation of pressure in the upper conduit and allow edifice deflation. In general, cycle period decreases with increasing magma supply rate until a threshold is reached, at which point periodicity disappears and extrusion rate becomes steady. Results are compared to well-documented cyclic phases of the ongoing eruption of the Soufrière Hills volcano, Montserrat, in order to demonstrate the appropriateness of this second formulation.

A Classification of Subaqueous Density Flows Based on Transformations From Proximal to Distal Regions

NASA Astrophysics Data System (ADS)

Hermidas, Navid; Eggenhuisen, Joris; Luthi, Stefan; Silva Jacinto, Ricardo; Toth, Ferenc; Pohl, Florian

2017-04-01

Transformations of a subaqueous density flow from proximal to distal regions are investigated. A classification of these transformations based on the state of the free shear and boundary layers and existence of a plug layer during transition from a debris flow to a turbidity current is presented. A connection between the emplaced deposit by the flow and the relevant flow type is drawn through the results obtained from a series of laboratory flume experiments. These were performed using 9%, 15%, and 21% sediment mixture concentrations composed of sand, silt, clay, and tap water, on varying bed slopes of 6°, 8°, and 9.5°, and with discharge rates of 10[m3/h] and 15[m3/h]. Stress-controlled rheometry experiments were performed on the mixtures to obtain apparent viscosity data. A classification was developed based on the imposed flow conditions, where a cohesive flow may fall within one of five distinct flow types: 1) a cohesive plug flow (PF) with a laminar free shear and boundary layers, 2) a top transitional plug flow (TTPF) containing a turbulent free shear layer, a plug layer, and a laminar boundary layer, 3) a complete transitional plug flow (CTPF) consisting of a turbulent free shear and boundary layers and a plug, 4) a transitional turbidity current (TTC) with a turbulent free shear layer and a laminar boundary layer, and, 5) a completely turbulent turbidity current (TC). During the experiments, flow type PF resulted in en masse deposition of a thick uniform ungraded muddy sand mixture, which was emplaced once the yield stress overcame the gravitational forces within the tail region of the flow. Flow type TTPF resulted in deposition of a thin ungraded basal clean sand layer during the run. This layer was covered by a muddy sand deposit from the tail. Flow type TTC did not deposit any sediment during the run. A uniform muddy sand mixture was emplaced by the tail of the flow. Flow type TC resulted in deposition of poorly sorted massive bottom sand layer. This layer was overlain by either a muddy sand mixture or a sand and silt planar lamination. Flow type CTPF was not observed during the experiments. Furthermore, it was observed that flows which are in transition from a TTC to a TTPF result in a thin bottom clean sand layer covered by a banded transitional interval. This was overlain by a muddy sand layer and a very thin clean sand layer, resulting from traction by dilute turbulent wake. In all cases a mud cap was emplaced on top of the deposit after the runs were terminated.

Anticorrosive Microbial Polysaccharides: Structure-Function Relationships

USDA-ARS?s Scientific Manuscript database

Water-soluble microbial polysaccharides are often implicated in biofilm formation and are believed to mediate cell-cell aggregation and adhesion to surfaces. Generally, biofilm formation is considered harmful or undesirable, as it leads to increased drag, plugging of pores, dimished heat transfer, ...

Geomorphic analysis of the Middle Rio Grande-Elephant Butte Reach, New Mexico

Treesearch

Tracy Elizabeth Owen

2012-01-01

The Elephant Butte Reach spans about 30 miles, beginning from the South Boundary of the Bosque del Apache National Wildlife Refuge (River Mile 73.9) to the "narrows" of the Elephant Butte Reservoir (River Mile 44.65), in central New Mexico. Sediment plugs occasionally form along the Middle Rio Grande, completely blocking the main channel of the river. In 1991...

Development and application of a three dimensional numerical model for predicting pollutant and sediment transport using an Eulerian-Lagrangian marker particle technique

NASA Technical Reports Server (NTRS)

Pavish, D. L.; Spaulding, M. L.

1977-01-01

A computer coded Lagrangian marker particle in Eulerian finite difference cell solution to the three dimensional incompressible mass transport equation, Water Advective Particle in Cell Technique, WAPIC, was developed, verified against analytic solutions, and subsequently applied in the prediction of long term transport of a suspended sediment cloud resulting from an instantaneous dredge spoil release. Numerical results from WAPIC were verified against analytic solutions to the three dimensional incompressible mass transport equation for turbulent diffusion and advection of Gaussian dye releases in unbounded uniform and uniformly sheared uni-directional flow, and for steady-uniform plug channel flow. WAPIC was utilized to simulate an analytic solution for non-equilibrium sediment dropout from an initially vertically uniform particle distribution in one dimensional turbulent channel flow.

Canister, Sealing Method And Composition For Sealing A Borehole

DOEpatents

Brown, Donald W.; Wagh, Arun S.

2005-06-28

Method and composition for sealing a borehole. A chemically bonded phosphate ceramic sealant for sealing, stabilizing, or plugging boreholes is prepared by combining an oxide or hydroxide and a phosphate with water to form slurry. The slurry is introduced into the borehole where the seal, stabilization or plug is desired, and then allowed to set up to form the high strength, minimally porous sealant, which binds strongly to itself and to underground formations, steel and ceramics.

Feline crystalluria. Detection and interpretation.

PubMed

Osborne, C A; Lulich, J P; Ulrich, L K; Bird, K A

1996-03-01

Crystalluria results from oversaturation of urine with crystallogenic substances. However, oversaturation may occur as a result of in vivo and in vitro events. Therefore, care must be used not to overinterpret the significance of crystalluria. Evaluation of urine crystals may aid in (1) detection of disorders predisposing cats to urolith or matrix-crystalline urethral plug formation; (2) estimation of the mineral composition of uroliths or urethral plugs; and (3) evaluation of the effectiveness of medical protocols initiated to dissolve or prevent urolithiasis.

Selenium impacts on razorback sucker, Colorado River, Colorado I. Adults.

PubMed

Hamilton, Steven J; Holley, Kathy M; Buhl, Kevin J; Bullard, Fern A; Ken Weston, L; McDonald, Susan F

2005-05-01

Adult razorback sucker (Xyrauchen texanus) were exposed to various selenium concentrations in ponds and isolated river channels of the Colorado River near Grand Junction, CO, to determine effects on their growth and residue accumulation over an 11-month period. Adults at Horsethief ponds were fed a commercial diet, whereas fish at Adobe Creek channel and North Pond foraged on natural food items. Selenium concentrations at Horsethief were 2.2 microg/L in water, 0.1-1.4 microg/g in sediment, and 2.3-3.1 microg/g in food organisms (1.1 microg/g in commercial fish food), at Adobe Creek were 3.8 microg/L in water, 0.5-2.1 microg/g in sediment, and 4-56 microg/g in food organisms, and at North Pond were 9.5 microg/L in water, 7-55 microg/g in sediment, and 20-81 microg/g in food organisms. The selenium concentrations in muscle plugs from adults at Adobe Creek (11.7 microg/g, SD = 0.4, n = 6) and North Pond (16.6 microg/g, SD = 1.0, n = 6) were greater than at Horsethief (4.5 microg/g, SD = 0.2, n = 6). During a depuration period adults from Adobe Creek and North Pond lost 1-2% of their selenium burden in 32 days and 14-19% in 66 days. Selenium accumulated in razorback sucker above toxic thresholds reported in other studies, yet those residues were less than those reported in muscle plugs of 40% of wild razorback sucker caught in the Green River, Utah.

The embryologic development of the human external auditory meatus. Preliminary report.

PubMed

Nishimura, Y; Kumoi, T

1992-01-01

During the final period of embryogenesis, a funnel-shaped tube continues medially into the mesenchymal tissue forming a curved path. Although this may sound simple, the development occurring during early fetal life is in fact very complex. At first, ectodermal cells proliferate to fill the lumen of the meatus, forming the meatal plug, and then at 10 weeks the bottom of the plug extends in a disc-like fashion, so that in the horizontal plane the meatus is boot-shaped with a narrow neck and the sole of the meatal plug spreading widely to form the future tympanic membrane medially. At the same time, the plug in the proximal portion of the neck starts to be resorbed. In the 13-week fetus, the disc-like plug begins to show signs of its final destiny; the innermost surface of the plug in contact with the anlage of the malleus is ready to contribute to the formation of the tympanic membrane. In the 15-week fetus, the innermost portion of the disc-like plug splits, leaving a thin ectodermal cell layer of immature tympanic membrane. The neck of the boot forms the border between the primary and secondary meatus, and is the last part to split. In the 16.5-week fetus, the meatus is fully patent throughout its entire length, although the lumen is still narrow and curved. In the 18-week fetus, the meatus is already fully expanded to its complete form.

Helicopter Surveys for Locating Wells and Leaking Oilfield Infrastructure

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

Hammack, R.W.; Veloski, G.A.; Hodges, G.

2006-10-01

Prior to the injection of CO2 into geological formations, either for enhanced oil recovery or for CO2 sequestration, it is necessary to locate wells that perforate the target formation and are within the radius of influence for planned injection wells. Locating and plugging wells is necessary because improperly plugged well bores provide the most rapid route for CO2 escape to the surface. This paper describes the implementation and evaluation of helicopter and ground-based well detection strategies at a 100+ year old oilfield in Wyoming where a CO2 flood is planned. This project was jointly funded by the U.S. Department ofmore » Energy’s National Energy Technology Laboratory and Fugro Airborne Surveys« less

Gas bubble formation and its pressure signature in T-junction of a microreactor

NASA Astrophysics Data System (ADS)

Pouya, Shahram; Koochesfahani, Manoochehr

2013-11-01

The segmented gas-liquid flow is of particular interest in microreactors used for high throughput material synthesis with enhanced mixing and more efficient reaction. A typical geometry to introduce gas plugs into the reactor is a T-junction where the dispersed liquid is squeezed and pinched by the continuous fluid in the main branch of the junction. We present experimental data of time resolved pressure along with synchronous imaging of the drop formation at the junction to show the transient behavior of the process. The stability of the slug regime and the regularity of the slug/plug pattern are investigated in this study. This work was supported by the CRC Program of the National Science Foundation, Grant Number CHE-0714028.

Isolation of Strain MLTeJB From Mono Lake, California, a Dissimilatory Tellurite Respiring Prokaryote.

NASA Astrophysics Data System (ADS)

Baesman, S. M.; Oremland, R. S.

2007-12-01

Previous investigations on the dissimilatory reduction of Te-oxyanions have been constrained by the inhibtory effects of circa 1.0 mM concentrations of either Te(IV) or Te(VI) upon growth of established cultures. Therefore we initiated new enrichments using anoxic Mono Lake mud supplemented with 10 mM Te(IV) as the electron acceptor and lactate as the electron donor. Sediments turned black with time owing to the formation of Te(0), microscopic examination of which confirmed the presence of both shards, rosettes, and nanospheres of Te(0). The enrichment was subcultured several times in liquid medium and then streaked onto solid medium and incubated in an anaerobic chamber. Isolated black colonies were re-streaked several times, and thence inoculated into liquid medium. However, growth in liquid medium required the presence of a small amount of solid phase, which included a plug of either agar, phytagel, or glass beads. Growth resulted in oxidation of lactate to acetate, formate and CO2 with the reduction of Te(IV) to Te(0). The isolate, strain MLTeJB was a non-motile rod that stained Gram positive, and formed copious exogenous deposits of Te(0) nano-shards and rosettes. Further details on the physiology of this organism will be presented.

Bubbling and foaming assisted clearing of mucin plugs in microfluidic Y-junctions.

PubMed

Abdula, Daner; Lerud, Ryan; Rananavare, Shankar

2017-11-07

Microfluidic Y-junctions were used to study mechanical mechanisms involved in pig gastric mucin (PGM) plug removal from within one of two bifurcation branches with 2-phase air and liquid flow. Water control experiments showed moderate plug removal due to shear from vortex formation in the blockage branch and suggest a PGM yield stress of 35Pa, as determined by computational fluid dynamics. Addition of hexadecyltrimethylammonium bromide (CTAB) surfactant improved clearing effectiveness due to bubbling in 1mm diameter channels and foaming in 500μm diameter channels. Plug removal mechanisms have been identified as vortex shear, bubble scouring, and then foam scouring as air flow rate is increased with constant liquid flow. The onset of bubbling and foaming is attributed to a flow regime transition from slug to slug-annular. Flow rates explored for 1mm channels are typically experienced by bronchioles in generations 8 and 9 of lungs. Results have implications on treatment of cystic fibrosis and other lung diseases. Copyright © 2016 Elsevier Ltd. All rights reserved.

How a small noise generates large-amplitude oscillations of volcanic plug and provides high seismicity

NASA Astrophysics Data System (ADS)

Alexandrov, Dmitri V.; Bashkirtseva, Irina A.; Ryashko, Lev B.

2015-04-01

A non-linear behavior of dynamic model of the magma-plug system under the action of N-shaped friction force and stochastic disturbances is studied. It is shown that the deterministic dynamics essentially depends on the mutual arrangement of an equilibrium point and the friction force branches. Variations of this arrangement imply bifurcations, birth and disappearance of stable limit cycles, changes of the stability of equilibria, system transformations between mono- and bistable regimes. A slope of the right increasing branch of the friction function is responsible for the formation of such regimes. In a bistable zone, the noise generates transitions between small and large amplitude stochastic oscillations. In a monostable zone with single stable equilibrium, a new dynamic phenomenon of noise-induced generation of large amplitude stochastic oscillations in the plug rate and pressure is revealed. A beat-type dynamics of the plug displacement under the influence of stochastic forcing is studied as well.

Java Library for Input and Output of Image Data and Metadata

NASA Technical Reports Server (NTRS)

Deen, Robert; Levoe, Steven

2003-01-01

A Java-language library supports input and output (I/O) of image data and metadata (label data) in the format of the Video Image Communication and Retrieval (VICAR) image-processing software and in several similar formats, including a subset of the Planetary Data System (PDS) image file format. The library does the following: It provides low-level, direct access layer, enabling an application subprogram to read and write specific image files, lines, or pixels, and manipulate metadata directly. Two coding/decoding subprograms ("codecs" for short) based on the Java Advanced Imaging (JAI) software provide access to VICAR and PDS images in a file-format-independent manner. The VICAR and PDS codecs enable any program that conforms to the specification of the JAI codec to use VICAR or PDS images automatically, without specific knowledge of the VICAR or PDS format. The library also includes Image I/O plugin subprograms for VICAR and PDS formats. Application programs that conform to the Image I/O specification of Java version 1.4 can utilize any image format for which such a plug-in subprogram exists, without specific knowledge of the format itself. Like the aforementioned codecs, the VICAR and PDS Image I/O plug-in subprograms support reading and writing of metadata.

The effect of paleotopography on lithic distribution and facies associations of small volume ignimbrites: the WTT Cupa (Roccamonfina volcano, Italy)

NASA Astrophysics Data System (ADS)

Giordano, Guido

1998-12-01

The distribution of lithic clasts within two trachytic, small volume, pumiceous ignimbrites are described from the Quaternary `White Trachytic Tuff Cupa' formation of Roccamonfina volcano, Italy. The ignimbrites show a downslope grading of lithics, with a maximum size where there is a major break in the volcano's slope, rather than at proximal locations. This is also the location where ignimbrites are thickest and most massive. The break in slope is interpreted to have reduced flow capacity and velocity, increasing the sedimentation rate, so that massive ignimbrite formed by hindered settling sedimentation. Ignimbrite Cc, exhibits no vertical grading of lithics, though it does show downslope grading with maximum size at the major break in slope and a rapid decrease further downslope. Ignimbrite Cc thins away from the break in slope, and shows an upward fining of the grain size within the topmost few decimeters of the unit. The ignimbrite is stratified proximally, and grades to massive facies at the break in slope, and distally to stratified facies with numerous inverse-graded beds. The simplest mechanism accounting for these downslope variations is progressive aggradation from a quasi-steady, nonuniform pyroclastic density current. The changes in deposit thickness and facies are interpreted to record downcurrent changes in sedimentation rate. The upward fining reflects waning flow. Inversely graded, bedded depositional facies in distal areas is interpreted to reflect flow unsteadiness and a decrease in suspended sediment load. Ignimbrite Cd shows vertical, as well as downslope grading of lithics. This characteristic, coupled with the widespread massive facies of the deposit and the tabular unit geometry are features that can be reconciled with both the debris flow/plug analogy for pyroclastic flows ( Sparks, 1976) and the progressive aggradation model ( Branney and Kokelaar, 1992). However, none of them appears to satisfy completely the field evidences, implying that when dealing with massive ignimbrites, other evidence than lithic grading needs to be presented to better understand the related transport and depositional processes.

Beyond Colorado's Front Range - A new look at Laramide basin subsidence, sedimentation, and deformation in north-central Colorado

USGS Publications Warehouse

Cole, James C.; Trexler, James H.; Cashman, Patricia H.; Miller, Ian M.; Shroba, Ralph R.; Cosca, Michael A.; Workman, Jeremiah B.

2010-01-01

This field trip highlights recent research into the Laramide uplift, erosion, and sedimentation on the western side of the northern Colorado Front Range. The Laramide history of the North Park?Middle Park basin (designated the Colorado Headwaters Basin in this paper) is distinctly different from that of the Denver basin on the eastern flank of the range. The Denver basin stratigraphy records the transition from Late Cretaceous marine shale to recessional shoreline sandstones to continental, fluvial, marsh, and coal mires environments, followed by orogenic sediments that span the K-T boundary. Upper Cretaceous and Paleogene strata in the Denver basin consist of two mega-fan complexes that are separated by a 9 million-year interval of erosion/non-deposition between about 63 and 54 Ma. In contrast, the marine shale unit on the western flank of the Front Range was deeply eroded over most of the area of the Colorado Headwaters Basin (approximately one km removed) prior to any orogenic sediment accumulation. New 40Ar-39Ar ages indicate the oldest sediments on the western flank of the Front Range were as young as about 61 Ma. They comprise the Windy Gap Volcanic Member of the Middle Park Formation, which consists of coarse, immature volcanic conglomerates derived from nearby alkalic-mafic volcanic edifices that were forming at about 65?61 Ma. Clasts of Proterozoic granite, pegmatite, and gneiss (eroded from the uplifted core of the Front Range) seem to arrive in the Colorado Headwaters Basin at different times in different places, but they become dominant in arkosic sandstones and conglomerates about one km above the base of the Colorado Headwaters Basin section. Paleocurrent trends suggest the southern end of the Colorado Headwaters Basin was structurally closed because all fluvial deposits show a northward component of transport. Lacustrine depositional environments are indicated by various sedimentological features in several sections within the >3 km of sediment preserved in the Colorado Headwaters Basin, suggesting this basin may have remained closed throughout the Paleocene and early Eocene. The field trip also addresses middle Eocene(?) folding of the late Laramide basin-fill strata, related to steep reverse faults that offset the Proterozoic crystalline basement. Late Oligocene magmatic activity is indicated by dikes, plugs, and eruptive volcanic rocks in the Rabbit Ears Range and the Never Summer Mountains that span and flank the Colorado Headwaters Basin. These intrusions and eruptions were accompanied by extensional faulting along predominantly northwesterly trends. Erosion accompanied the late Oligocene igneous activity and faulting, leading to deposition of boulder conglomerates and sandstones of the North Park Formation and high-level conglomerates across the landscape that preserve evidence of a paleo-drainage network that drained the volcanic landscape.

Depositional evolution of permo-triassic karoo basins in Tanzania with reference to their economic potential

NASA Astrophysics Data System (ADS)

Kreuser, T.; Wopfner, H.; Kaaya, C. Z.; Markwort, S.; Semkiwa, P. M.; Aslandis, P.

The Karoo basins of Tanzania contain in excess of 3000 m of sediments which were preserved in several NNE-NE striking half grabens or other structural basin conditions. They are all intracratonic basins, most of which filled with terrestrial sediments. In some basins situated nearer the coastal region short marine incursions occurred in the Late Permian. The Ruhuhu Rasin in SW Tanzania provides a typical depositional sequence of a Karoo basin in eastern Africa. Sedimentation commenced with glacigene deposits. These are of Late Carboniferous to Early Permian age and may be equated with other glacial successions in Africa and elsewhere in Gondwana. The glacigene beds are overlain by fluvial-deltaic coal-bearing deposits succeeded by arkoses and continental red beds. A transitionary formation of carbonaceous shales with impure coals gradually develops into thick lacustrine series which are topped by Late Permian bone bearing beds. The Triassic is characterized by a very thick fluvio-deltaic succession of siliciclastics resting with regional unconformity on the Permian. This Early Triassic sequence exhibits well-developed repetitive depositional cycles. Current azimuth measurements indicate fluctuating flow regimes in the Early Permian but relative stable source areas to the west of the basin later on. The depositional evolution of the Ruhuhu Basin is controlled by both tectonic and climatic factors. During basin evolution important energy resources were deposited such as considerable reserves of coal and source rocks of moderate potential for hydrocarbon generation. Uranium enrichment is observed in the Triassic arenaceous series where diagenetic alterations and subsequent cementation processes led to the formation of laumontite. Post Karoo dykes and plugs had only local effect on thermal evolution of potential source rocks. Enrichments of elements, i.e., Nb, Zr, Rb, Cr, and V present additional exploration targets. A comparison with the Karoo basins of the coastal region indicates possible lithological correlation by the application of sequence stratigraphy. No early Permian deposits are exposed in the coastal Karoo basins but their existence within the deeper parts of these basins cannot be ruled out. There, composition of organic matter analysed so far suggests subsidence and heat exposure exceeding post maturity stage.

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

USGS Publications Warehouse

Winters, W.; Walker, M.; Hunter, R.; Collett, T.; Boswell, R.; Rose, K.; Waite, W.; Torres, M.; Patil, S.; Dandekar, A.

2011-01-01

This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography.This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4. m-627.9. m); unit C-GH1 (649.8. m-660.8. m); and unit C-GH2 (663.2. m-666.3. m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate.In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average "plug" intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7. mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude. ?? 2010.

Physical properties of sediment from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

USGS Publications Warehouse

Winters, William J.; Walker, Michael; Hunter, Robert; Collett, Timothy S.; Boswell, Ray M.; Rose, Kelly K.; Waite, William F.; Torres, Marta; Patil, Shirish; Dandekar, Abhijit

2011-01-01

This study characterizes cored and logged sedimentary strata from the February 2007 BP Exploration Alaska, Department of Energy, U.S. Geological Survey (BPXA-DOE-USGS) Mount Elbert Gas Hydrate Stratigraphic Test Well on the Alaska North Slope (ANS). The physical-properties program analyzed core samples recovered from the well, and in conjunction with downhole geophysical logs, produced an extensive dataset including grain size, water content, porosity, grain density, bulk density, permeability, X-ray diffraction (XRD) mineralogy, nuclear magnetic resonance (NMR), and petrography. This study documents the physical property interrelationships in the well and demonstrates their correlation with the occurrence of gas hydrate. Gas hydrate (GH) occurs in three unconsolidated, coarse silt to fine sand intervals within the Paleocene and Eocene beds of the Sagavanirktok Formation: Unit D-GH (614.4 m-627.9 m); unit C-GH1 (649.8 m-660.8 m); and unit C-GH2 (663.2 m-666.3 m). These intervals are overlain by fine to coarse silt intervals with greater clay content. A deeper interval (unit B) is similar lithologically to the gas-hydrate-bearing strata; however, it is water-saturated and contains no hydrate. In this system it appears that high sediment permeability (k) is critical to the formation of concentrated hydrate deposits. Intervals D-GH and C-GH1 have average "plug" intrinsic permeability to nitrogen values of 1700 mD and 675 mD, respectively. These values are in strong contrast with those of the overlying, gas-hydrate-free sediments, which have k values of 5.7 mD and 49 mD, respectively, and thus would have provided effective seals to trap free gas. The relation between permeability and porosity critically influences the occurrence of GH. For example, an average increase of 4% in porosity increases permeability by an order of magnitude, but the presence of a second fluid (e.g., methane from dissociating gas hydrate) in the reservoir reduces permeability by more than an order of magnitude.

Situ microbial plugging process for subterranean formations

DOEpatents

McInerney, Michael J.; Jenneman, Gary E.; Knapp, Roy M.; Menzie, Donald E.

1985-12-17

Subterranean paths of water flow are impeded or changed by the facilitation of microbial growth therein. Either indigenous bacterial growth may be stimulated with nutrients or the formation may be first seeded with bacteria or their spores which inhibit fluid flow after proliferation. These methods and bacteria are usable to alter the flow of water in a waterflooded oil formation and to impede the outflow of contaminated water.

Selenium impacts on razorback sucker, Colorado River, Colorado: I. Adults

USGS Publications Warehouse

Hamilton, S.J.; Holley, K.M.; Buhl, K.J.; Bullard, F.A.; Weston, L.K.; McDonald, S.F.

2005-01-01

Adult razorback sucker (Xyrauchen texanus) were exposed to various selenium concentrations in ponds and isolated river channels of the Colorado River near Grand Junction, CO, to determine effects on their growth and residue accumulation over an 11-month period. Adults at Horsethief ponds were fed a commercial diet, whereas fish at Adobe Creek channel and North Pond foraged on natural food items. Selenium concentrations at Horsethief were 2.2 μg/L in water, 0.1–1.4 μg/g in sediment, and 2.3–3.1 μg/g in food organisms (1.1 μg/g in commercial fish food), at Adobe Creek were 3.8 μg/L in water, 0.5–2.1 μg/g in sediment, and 4–56 μg/g in food organisms, and at North Pond were 9.5 μg/L in water, 7–55 μg/g in sediment, and 20–81 μg/g in food organisms. The selenium concentrations in muscle plugs from adults at Adobe Creek (11.7 μg/g, SD=0.4, n=6) and North Pond (16.6 μg/g, SD=1.0, n=6) were greater than at Horsethief (4.5 μg/g, SD=0.2, n=6). During a depuration period adults from Adobe Creek and North Pond lost 1–2% of their selenium burden in 32 days and 14–19% in 66 days. Selenium accumulated in razorback sucker above toxic thresholds reported in other studies, yet those residues were less than those reported in muscle plugs of 40% of wild razorback sucker caught in the Green River, Utah.

A novel model of acellular dermal matrix plug for anal fistula treatment. Report of a case and surgical consideration based on first utility in Poland.

PubMed

Bobkiewicz, Adam; Krokowicz, Łukasz; Borejsza-Wysocki, Maciej; Banasiewicz, Tomasz

2017-08-31

Anal fistula (AF) is a pathological connection between anus and skin in its surroundings. The main reason for the formation of anal fistula is a bacterial infection of the glands within the anal crypts. One of the modern techniques for the treatment of fistulas that do not interfere with the sphincters consists in implantation of a plug made from collagen material. We are presenting the first Polish experience with a new model of biomaterial plug for the treatment of anal fistula. We also point out key elements of the procedure (both preoperative and intraoperative) associated with this method. In the authors' opinion, the method is simple, safe and reproducible. Innovative shape of the plug minimizes the risk of its migration and rotation. It also perfectly blends with and adapts to the course and shape of the fistula canal, allowing it to become incorporated and overgrown with tissue in the fistula canal. The relatively short operation time, minor postoperative pain and faster convalescence are with no doubt additional advantages of the method. Long-term observation involving more patients is essential for evaluation of the efficacy of the treatment of fistulas with the new type of plug.

Double-cross hydrostatic pressure sample injection for chip CE: variable sample plug volume and minimum number of electrodes.

PubMed

Luo, Yong; Wu, Dapeng; Zeng, Shaojiang; Gai, Hongwei; Long, Zhicheng; Shen, Zheng; Dai, Zhongpeng; Qin, Jianhua; Lin, Bingcheng

2006-09-01

A novel sample injection method for chip CE was presented. This injection method uses hydrostatic pressure, generated by emptying the sample waste reservoir, for sample loading and electrokinetic force for dispensing. The injection was performed on a double-cross microchip. One cross, created by the sample and separation channels, is used for formation of a sample plug. Another cross, formed by the sample and controlling channels, is used for plug control. By varying the electric field in the controlling channel, the sample plug volume can be linearly adjusted. Hydrostatic pressure takes advantage of its ease of generation on a microfluidic chip, without any electrode or external pressure pump, thus allowing a sample injection with a minimum number of electrodes. The potential of this injection method was demonstrated by a four-separation-channel chip CE system. In this system, parallel sample separation can be achieved with only two electrodes, which is otherwise impossible with conventional injection methods. Hydrostatic pressure maintains the sample composition during the sample loading, allowing the injection to be free of injection bias.

On the presence of prostatic secretion protein in rat seminal fluid

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

Borgstroem, E.; Pousette, A.; Bjoerk, P.

1981-01-01

The copulating plug collected from the tip of the penis from rats immediately after decapitation contains a protein very similar and probably identical to PSP (prostatic secretion protein); this protein has earlier been purified from rat prostatic cytosol and characterized. The protein present in the copulating plug interacts with (3H)estramustine and binds to the antibody raised against rat PSP. The concentration of the protein in the copulating plug is 400 ng/mg of total protein, when measured using the radioimmunoassay technique developed earlier for measurement of PSP in rat prostate. The (3H)estramustine-protein complex formed in a preparation of the copulating plugmore » has an apparent molecular weight of about 50,000 and a sedimentation coefficient of about 3S when analyzed using sucrose density gradient centrifugation. The complex was retained on Concanavalin-A Sepharose indicating that the protein is a glycoprotein. Binding of the complex was also observed on hydroxylapatite and DEAE-Sephadex columns, from which it was eluted at 0.18 M KCl. Light microscope autoradiograms of rat sperms incubated with 125I-labeled PSP indicated that PSP is bound to all parts of the sperms. A macromolecule interacting with the PSP-antibodies is also present in human seminal fluid but at a concentration considerably lower than in rat seminal fluid. The present study shows that a macromolecule probably identical to prostatic secretion protein is present in the copulating plug from the rat. The biological role of this protein in normal male fertility is discussed.« less

Characterization of the Triassic Newark Basin of New York and New Jersey for geologic storage of carbon dioxide

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

Collins, Daniel J.

The Newark Basin is a Triassic-aged rift basin underlying densely populated, industrialized sections of New York, New Jersey and Pennsylvania. The Basin is an elongate half-graben encompassing an area of more than 7,510 square-kilometers (2,900 square-miles), and could represent a key storage component for commercial scale management of carbon dioxide emissions via geologic sequestration. The project team first acquired published reports, surface and subsurface maps, and seismic data, which formed the basis for a three-dimensional model framework for the northern end of the Basin incorporating stratigraphic, hydrologic, and water quality data. Field investigations included drilling, coring, and logging of two stratigraphic test borings in Clarkstown, NY (Exit 14 Tandem Lot Well No. 1), drilled to a depth of 2,099 meters (6,885 feet); and Palisades, NY (Lamont-Doherty Earth Observatory Test Well No. 4) drilled to a depth of 549 meters (1,802 feet). Two two-dimensional seismic reflection data lines arrayed perpendicularly were acquired by Schlumberger/WesternGeco to help characterize the structure and stratigraphy and as part of pre-drilling field screening activities for the deep stratigraphic borehole. A total of 47 meters (155 feet) of continuous whole core was recovered from the Tandem Lot boring from depths of 1,393 meters (4,570 feet) to 1,486 meters (4,877 feet). Twenty-five horizontal rotary cores were collected in mudstones and sandstones in the surface casing hole and fifty-two cores were taken in various lithologies in the deep borehole. Rotary core plugs were analyzed by Weatherford Laboratories for routine and advanced testing. Rotary core plug trim end thin sections were evaluated by the New York State Museum for mineralogical analysis and porosity estimation. Using core samples, Lawrence Berkley National Laboratory designed and completed laboratory experiments and numerical modeling analyses to characterize the dissolution and reaction of carbon dioxide with formation brine and minerals, and resulting effects on injection rate, pressure, effective storage volume, and carbon dioxide migration within a prospective sandstone reservoir.more » $$Three potential porous and permeable sandstone units were identified in the Passaic Formation at the New York State Thruway Exit 14 location. Potential Flow Unit 1, at a depth of 643 meters (2,110 feet) to 751 meters (2,465 feet); Potential Flow Unit 2 at a depth of 853 meters (2,798 feet) to 1,000 meters (3,280 feet); and Potential Flow Unit 3, at a depth of 1,114 meters (3,655 feet) to 1,294 meters (4,250 feet). Reactive transport simulations of interactions between carbon dioxide, brine and formation minerals were carried out to evaluate changes in formation water chemistry, mineral precipitation and dissolution reactions, and any potential resulting effects on formation permeability. The experimental and modeling analyses suggest that mineral precipitation and dissolution reactions (within the target formation) are not expected to lead to significant changes to the underground hydrologic system over time frames (~30 years) typically relevant for carbon dioxide injection operations. Key findings of this basin characterization study include an estimate of carbon dioxide storage capacity in the Newark Basin. Assuming an average porosity of twelve percent and an aquifer volume of 6.1E+12 meters3, calculated ranges of likely storage capacity range from 1.9 – 20.2 gigatonnes under high temperature (low carbon dioxide density) conditions; and 2.9 – 30.2 gigatonnes under low temperature (low carbon dioxide density) conditions. Intra-basin faulting, geometry of the Palisades Sill, and the presence of altered meta-sediments above and below the Sill, increase potential compartmentalization within the basin. A structural/stratigraphic trap type may occur where porous/permeable sediments are cross-cut by the Palisades Sill. Potential injection intervals are present within the Stockton Formation of the Newark Basin. Additional porous/permeable intervals may be present within sandstones of the Passaic Formation, increasing projected storage capacity. Deeper wedges of strata are likely present in the deeper portions of the basin in southern New York and into northern New Jersey. Abundant mudstones are present in the Passaic, Lockatong, and Stockton Formations. These intervals have the requisite petrophysical properties to form effective primary and secondary containment intervals to industrial-scale sequestration of carbon dioxide in the Newark Basin. Hydro-thermally altered meta-sediments in the region immediately surrounding the top and base of the Palisades Sill is devoid of porosity/permeability and forms an additional effective lateral/vertical sealing cap rock.« less

An object oriented fully 3D tomography visual toolkit.

PubMed

Agostinelli, S; Paoli, G

2001-04-01

In this paper we present a modern object oriented component object model (COMM) C + + toolkit dedicated to fully 3D cone-beam tomography. The toolkit allows the display and visual manipulation of analytical phantoms, projection sets and volumetric data through a standard Windows graphical user interface. Data input/output is performed using proprietary file formats but import/export of industry standard file formats, including raw binary, Windows bitmap and AVI, ACR/NEMA DICOMM 3 and NCSA HDF is available. At the time of writing built-in implemented data manipulators include a basic phantom ray-tracer and a Matrox Genesis frame grabbing facility. A COMM plug-in interface is provided for user-defined custom backprojector algorithms: a simple Feldkamp ActiveX control, including source code, is provided as an example; our fast Feldkamp plug-in is also available.

Publications - GMC 232 | Alaska Division of Geological & Geophysical

Science.gov Websites

Surveys Skip to content State of Alaska myAlaska My Government Resident Business in Alaska DGGS GMC 232 Publication Details Title: Petrographic analysis and formation damage potential of core Reference Hickey, J.J., 1994, Petrographic analysis and formation damage potential of core plugs (12,017

Effects of shallow basaltic intrusion into pyroclastic deposits, Grants Ridge, New Mexico, USA

NASA Astrophysics Data System (ADS)

WoldeGabriel, Giday; Keating, Gordon N.; Valentine, Greg A.

1999-10-01

A localized aureole up to 10 m wide developed around a 150-m-wide, 2.6 Ma basaltic plug at Grants Ridge, New Mexico. The plug intruded into nonwelded, pumice-rich compositionally homogenous tuff and volcaniclastic sediments of similar age (3.3 Ma). Color variation (pinkish to orange), strong local contact welding, brecciation, partial melting, and stoping characterize the host rock within the contact zone. Despite the high-temperature basaltic intrusion, there is no indication of extensive fluid-driven convective heat transfer and pervasive hydrothermal circulation and alteration of the country rock. The proportion of volcanic glass, loss on ignition (LOI), fluorine, iron, and some trace and rare earth element contents in the host rocks are somewhat depleted at the contact of the intrusion. Conversely, the degree of devitrification and the potassium content are higher along the contact. Vapor-phase expulsion of elemental species as complexes of fluoride, chloride, hydroxide, sulfide, and carbon dioxide may have been responsible for the minor depletion of the elements during the devitrification of silicic glass at near-solidus temperature related to the basaltic intrusion. The results of finite-difference numerical modeling of the intrusion as a dry, conduction-dominated system agree well with geochemical and mineralogical data. Contact welding of the host rocks apparently occurred at temperatures >700°C under a density-driven lateral load of approximately 1 MPa, corresponding to the observed depth below the former ground surface of ˜100 m. Other physical changes in the first 10 m of host rock, represented by partial devitrification and color changes, apparently occurred at temperatures of 500-600°C, which probably persisted for up to 55 years after the emplacement of the basaltic plug. Devitrification is generally enhanced by the presence of aqueous fluids; however, the abundance of volcanic glass within a short distance (˜10 m) from the plug is consistent with our inference that the plug intruded into a dry (unsaturated) environment.

Enrichment and isolation of Bacillus beveridgei sp. nov., a facultative anaerobic haloalkaliphile from Mono Lake, California, that respires oxyanions of tellurium, selenium, and arsenic

USGS Publications Warehouse

Baesman, S.M.; Stolz, J.F.; Kulp, T.R.; Oremland, R.S.

2009-01-01

Mono Lake sediment slurries incubated with lactate and tellurite [Te(IV)] turned progressively black with time because of the precipitation of elemental tellurium [Te(0)]. An enrichment culture was established from these slurries that demonstrated Te(IV)-dependent growth. The enrichment was purified by picking isolated black colonies from lactate/Te(IV) agar plates, followed by repeated streaking and picking. The isolate, strain MLTeJB, grew in aqueous Te(IV)-medium if provided with a small amount of sterile solid phase material (e.g., agar plug; glass beads). Strain MLTeJB grew at high concentrations of Te(IV) (~8 mM) by oxidizing lactate to acetate plus formate, while reducing Te(IV) to Te(0). Other electron acceptors that were found to sustain growth were tellurate, selenate, selenite, arsenate, nitrate, nitrite, fumarate and oxygen. Notably, growth on arsenate, nitrate, nitrite and fumarate did not result in the accumulation of formate, implying that in these cases lactate was oxidized to acetate plus CO2. Strain MLTeJB is a low G + C Gram positive motile rod with pH, sodium, and temperature growth optima at 8.5-9.0, 0.5-1.5 M, and 40??C, respectively. The epithet Bacillus beveridgei strain MLTeJBT is proposed. ?? 2009 Springer.

Oscillation of an isolated liquid plug inside a dry capillary

NASA Astrophysics Data System (ADS)

Srinivasan, Vyas; Kumar, Siddhartha; Asfer, Mohammed; Khandekar, Sameer

2017-11-01

The present work reports an experimental study on the dynamics of partially wetting isolated liquid plug (DI water), which is made to oscillate inside a square, glass capillary tube (1 mm × 1 mm; 60 mm length). The liquid plug is made to oscillate pneumatically at two different frequencies (0.25 and 0.35 Hz), using a cam-follower mechanism. Bright field imaging is used to visualize the three-phase contact line behavior, while, micro-Particle Imaging Velocimetry (PIV) apparatus is used to discern the nature of flow inside the oscillating liquid plug. During a cycle, due to the partial wetting nature of DI water, the three-phase contact line at the menisci gets pinned at the extreme end of each stroke, where the dynamic apparent contact angle gets drastically altered before the initiation of the next stroke. The difference between the apparent contact angle of the front and rear meniscus are seen to be a function of the oscillating frequency; the difference increasing with increasing frequency. The flow inside the liquid plug reveals unique non-Poiseuille flow features near the meniscus, due to free-slip boundary condition, which leads to formation of distinct vortex pairs behind it. The vortices too change their direction during each stroke of the oscillation, eventually leading to an alternating recirculation pattern inside the plug. The results clearly indicate that improved mathematical models are required for predicting transport parameters in such flows, which are important in engineering systems such as pulsating heat pipes, lab-on-chip devices and PEM fuel cells.

Stratigraphy, depositional environments, and carbonate petrology of the Toroweap and Kaibab Formations (lower Permian), Grand Canyon region, Arizona

NASA Astrophysics Data System (ADS)

Clark, R. A.

Sediments deposited in northwestern Arizona during Late Leonardian and Early Guadalupian (Permian) were controlled chiefly by an arid climate and the tectonic setting. Eastward thrusting of eugeosynclinal rocks onto miogeosynclinal deposits during Middle Devonian to Early Mississippian had a major influence on shelf sedimentation. The Toroweap and Kaibab formations represent two such platform sequences of northwestern Arizona and southern Utah deposited during this phase of sedimentation. The Toroweap Formation is subdivided into three members and represents sediments deposited during initial transgression, maximum extent of the sea, and regression (Seligman, Brady Canyon, and Woods Ranch members respectively). The Fossil Mountain Member of the Kaibab Formation documents the most extensive phase of sedimentation for all members of the Toroweap and Kaibab formations. The Harrisburg Member documents the final phase of sedimentation at the close of the Paleozoic Era.

A small porous-plug burner for studies of combustion chemistry and soot formation

NASA Astrophysics Data System (ADS)

Campbell, M. F.; Schrader, P. E.; Catalano, A. L.; Johansson, K. O.; Bohlin, G. A.; Richards-Henderson, N. K.; Kliewer, C. J.; Michelsen, H. A.

2017-12-01

We have developed and built a small porous-plug burner based on the original McKenna burner design. The new burner generates a laminar premixed flat flame for use in studies of combustion chemistry and soot formation. The size is particularly relevant for space-constrained, synchrotron-based X-ray diagnostics. In this paper, we present details of the design, construction, operation, and supporting infrastructure for this burner, including engineering attributes that enable its small size. We also present data for charactering the flames produced by this burner. These data include temperature profiles for three premixed sooting ethylene/air flames (equivalence ratios of 1.5, 1.8, and 2.1); temperatures were recorded using direct one-dimensional coherent Raman imaging. We include calculated temperature profiles, and, for one of these ethylene/air flames, we show the carbon and hydrogen content of heavy hydrocarbon species measured using an aerosol mass spectrometer coupled with vacuum ultraviolet photoionization (VUV-AMS) and soot-volume-fraction measurements obtained using laser-induced incandescence. In addition, we provide calculated mole-fraction profiles of selected gas-phase species and characteristic profiles for seven mass peaks from AMS measurements. Using these experimental and calculated results, we discuss the differences between standard McKenna burners and the new miniature porous-plug burner introduced here.

A small porous-plug burner for studies of combustion chemistry and soot formation.

PubMed

Campbell, M F; Schrader, P E; Catalano, A L; Johansson, K O; Bohlin, G A; Richards-Henderson, N K; Kliewer, C J; Michelsen, H A

2017-12-01

We have developed and built a small porous-plug burner based on the original McKenna burner design. The new burner generates a laminar premixed flat flame for use in studies of combustion chemistry and soot formation. The size is particularly relevant for space-constrained, synchrotron-based X-ray diagnostics. In this paper, we present details of the design, construction, operation, and supporting infrastructure for this burner, including engineering attributes that enable its small size. We also present data for charactering the flames produced by this burner. These data include temperature profiles for three premixed sooting ethylene/air flames (equivalence ratios of 1.5, 1.8, and 2.1); temperatures were recorded using direct one-dimensional coherent Raman imaging. We include calculated temperature profiles, and, for one of these ethylene/air flames, we show the carbon and hydrogen content of heavy hydrocarbon species measured using an aerosol mass spectrometer coupled with vacuum ultraviolet photoionization (VUV-AMS) and soot-volume-fraction measurements obtained using laser-induced incandescence. In addition, we provide calculated mole-fraction profiles of selected gas-phase species and characteristic profiles for seven mass peaks from AMS measurements. Using these experimental and calculated results, we discuss the differences between standard McKenna burners and the new miniature porous-plug burner introduced here.

SED-ED, a workflow editor for computational biology experiments written in SED-ML.

PubMed

Adams, Richard R

2012-04-15

The simulation experiment description markup language (SED-ML) is a new community data standard to encode computational biology experiments in a computer-readable XML format. Its widespread adoption will require the development of software support to work with SED-ML files. Here, we describe a software tool, SED-ED, to view, edit, validate and annotate SED-ML documents while shielding end-users from the underlying XML representation. SED-ED supports modellers who wish to create, understand and further develop a simulation description provided in SED-ML format. SED-ED is available as a standalone Java application, as an Eclipse plug-in and as an SBSI (www.sbsi.ed.ac.uk) plug-in, all under an MIT open-source license. Source code is at https://sed-ed-sedmleditor.googlecode.com/svn. The application itself is available from https://sourceforge.net/projects/jlibsedml/files/SED-ED/.

Research and application of multi-hydrogen acidizing technology of low-permeability reservoirs for increasing water injection

NASA Astrophysics Data System (ADS)

Ning, Mengmeng; Che, Hang; Kong, Weizhong; Wang, Peng; Liu, Bingxiao; Xu, Zhengdong; Wang, Xiaochao; Long, Changjun; Zhang, Bin; Wu, Youmei

2017-12-01

The physical characteristics of Xiliu 10 Block reservoir is poor, it has strong reservoir inhomogeneity between layers and high kaolinite content of the reservoir, the scaling trend of fluid is serious, causing high block injection well pressure and difficulty in achieving injection requirements. In the past acidizing process, the reaction speed with mineral is fast, the effective distance is shorter and It is also easier to lead to secondary sedimentation in conventional mud acid system. On this point, we raised multi-hydrogen acid technology, multi-hydrogen acid release hydrogen ions by multistage ionization which could react with pore blockage, fillings and skeletal effects with less secondary pollution. Multi-hydrogen acid system has advantages as moderate speed, deep penetration, clay low corrosion rate, wet water and restrains precipitation, etc. It can reach the goal of plug removal in deep stratum. The field application result shows that multi-hydrogen acid plug removal method has good effects on application in low permeability reservoir in Block Xiliu 10.

Impacts of crab bioturbation and local pollution on sulfate reduction, Hg distribution and methylation in mangrove sediments, Rio de Janeiro, Brazil.

PubMed

Correia, Raquel Rose Silva; Guimarães, Jean Remy Davée

2016-08-15

Mercury (Hg) and methylmercury (MeHg) are highly toxic and poorly studied in mangroves. Burrowing Uca crabs change sediment topography and biogeochemistry and thus may affect Hg distribution and MeHg formation. We studied added (203)Hg distribution, Me(203)Hg formation and sulfate reduction rates (SRR) in sediment aquariums containing Uca leptodactyla; and analyzed profiles of Me(203)Hg formation and SRR in sediment cores from two mangroves with distinct environmental impacts. MeHg formation and SRR were higher in the top (≤6cm) sediment and there was no significant difference in Hg methylation in more or less impacted mangroves. In aquariums, crab bioturbation favored Hg retention in the sediment. In the treatment without crabs, Hg volatilization and water Hg concentrations were higher. Hg methylation was higher in bioturbated aquariums but SRR were similar in both treatments. These findings suggest that bioturbating activity favors Hg retention in sediment but also promotes MeHg formation near the surface. Copyright © 2016 Elsevier Ltd. All rights reserved.

Clog Retard of a Vortex Throttle Joule-Thomson Cryocooler: Further Experimental Verification

NASA Astrophysics Data System (ADS)

Maytal, B.-Z.

2010-04-01

The demand of high purity gas supply for Joule-Thomson cryocoolers and liquefiers is crucial in order to avoid plug formation at the delicate throttling device. A throttle which would tolerate higher level of contamination is greatly desirable for more reliable operation. The vortex throttle has such a potential. A series of vortex throttles were applied to a miniature Joule-Thomson cryocooler and tested with precisely contaminated coolant. The instantaneous flow rate and the mode of its decay indicate the rate and nature of plug formation. Each experiment was a simultaneous run of two cryocoolers in parallel at similar conditions: one with a traditional throttle of short hole, and the other one with the vortex throttle. The clog retard behavior of the vortex throttle was verified. It runs about 2.5 times longer than the traditional one, while being fed by water vapor contaminated nitrogen at the levels of 5 and 17 PPM. The contamination level by carbon dioxide was 80 PPM and exhibited a different behavior of clog formation. Its effect on the cryocooler temperature stability with the vortex throttle was quite minor.

Viscous plugging can enhance and modulate explosivity of strombolian eruptions

NASA Astrophysics Data System (ADS)

Del Bello, E.; Lane, S. J.; James, M. R.; Llewellin, E. W.; Taddeucci, J.; Scarlato, P.; Capponi, A.

2015-08-01

Strombolian activity is common in low-viscosity volcanism. It is characterised by quasi-periodic, short-lived explosions, which, whilst typically weak, may vary greatly in magnitude. The current paradigm for a strombolian volcanic eruption postulates a large gas bubble (slug) bursting explosively after ascending a conduit filled with low-viscosity magma. However, recent studies of pyroclast textures suggest the formation of a region of cooler, degassed, more-viscous magma at the top of the conduit is a common feature of strombolian eruptions. Following the hypothesis that such a rheological impedance could act as a 'viscous plug', which modifies and complicates gas escape processes, we conduct the first experimental investigation of this scenario. We find that: 1) the presence of a viscous plug enhances slug burst vigour; 2) experiments that include a viscous plug reproduce, and offer an explanation for, key phenomena observed in natural strombolian eruptions; 3) the presence and extent of the plug must be considered for the interpretation of infrasonic measurements of strombolian eruptions. Our scaled analogue experiments show that, as the gas slug expands on ascent, it forces the underlying low-viscosity liquid into the plug, creating a low-viscosity channel within a high-viscosity annulus. The slug's diameter and ascent rate change as it enters the channel, generating instabilities and increasing slug overpressure. When the slug reaches the surface, a more energetic burst process is observed than would be the case for a slug rising through the low-viscosity liquid alone. Fluid-dynamic instabilities cause low and high viscosity magma analogues to intermingle, and cause the burst to become pulsatory. The observed phenomena are reproduced by numerical fluid dynamic simulations at the volcanic scale, and provide a plausible explanation for pulsations, and the ejection of mingled pyroclasts, observed at Stromboli and elsewhere.

Hydrate-Bearing Clayey Sediments: Morphology, Physical Properties, Production and Engineering/Geological Implications

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

Dai, Sheng; Santamarina, J. Carlos

Fine-grained sediments host more than 90 percent of global gas hydrate accumulation. However, hydrate formation in clay-dominated sediments is less understood and characterized than other types of hydrate occurrence. There is an inadequate understanding of hydrate formation mechanisms, segregation structures, hydrate lens topology, system connectivity, and physical macro-scale properties of clay-dominated hydrate-bearing sediments. This situation hinders further analyses of the global carbon budget as well as engineering challenges/solutions related to hydrate instability and production. This project studies hydrate-bearing clay-dominated sediments with emphasis on the enhanced fundamental understanding of hydrate formation and resulting morphology, the development laboratory techniques to emulate naturalmore » hydrate formations, the assessment of analytical tools to predict physical properties, the evaluation of engineering and geological implications, and the advanced understanding of gas production potential from finegrained sediments.« less

Effects of the bilayer nano-hydroxyapatite/mineralized collagen-guided bone regeneration membrane on site preservation in dogs.

PubMed

Sun, Yi; Wang, Chengyue; Chen, Qixin; Liu, Hai; Deng, Chao; Ling, Peixue; Cui, Fu-Zhai

2017-08-01

This study was aimed at assessing the effects of the porous mineralized collagen plug with or without the bilayer mineralized collagen-guided bone regeneration membrane on alveolar ridge preservation in dogs. The third premolars in the bilateral maxilla of mongrel dogs ( N = 12) were extracted. Twenty-four alveolar sockets were thus randomly divided into three groups: membrane + collagen plug (MP, n = 8), nonmembrane + collagen plug (NP, n = 8) and blank group without any implantation (BG, n = 8). Radiographic assessment was carried out immediately and in the 2nd, 6th, and 12th week after surgery. The bone-repairing effects of the two grafts were respectively evaluated by clinical observation, X-ray micro-computed tomography examination, and histological analysis in the 8th and 12th week after surgery. Three groups presented excellent osseointegration without any inflammation or dehiscence. X-ray micro-computed tomography and histological assessment indicated that the ratios of new bone formation of MP group were significantly higher than those of NP group and BG group in the 8th and 12th week after surgery ( P < 0.05). As a result, the porous mineralized collagen plug with or without the bilayer mineralized collagen-guided bone regeneration membrane could reduce the absorption of alveolar ridge compared to BG group, and the combined use of porous mineralized collagen plug and bilayer mineralized collagen-guided bone regeneration could further improve the activity of bone regeneration.

Improved oil recovery using bacteria isolated from North Sea petroleum reservoirs

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

Davey, R.A.; Lappin-Scott, H.

1995-12-31

During secondary oil recovery, water is injected into the formation to sweep out the residual oil. The injected water, however, follows the path of least resistance through the high-permeability zones, leaving oil in the low-permeability zones. Selective plugging of these their zones would divert the waterflood to the residual oil and thus increase the life of the well. Bacteria have been suggested as an alternative plugging agent to the current method of polymer injection. Starved bacteria can penetrate deeply into rock formations where they attach to the rock surfaces, and given the right nutrients can grow and produce exo-polymer, reducingmore » the permeability of these zones. The application of microbial enhanced oil recovery has only been applied to shallow, cool, onshore fields to date. This study has focused on the ability of bacteria to enhance oil recovery offshore in the North Sea, where the environment can be considered extreme. A screen of produced water from oil reservoirs (and other extreme subterranean environments) was undertaken, and two bacteria were chosen for further work. These two isolates were able to grow and survive in the presence of saline formation waters at a range of temperatures above 50{degrees}C as facultative anaerobes. When a solution of isolates was passed through sandpacks and nutrients were added, significant reductions in permeabilities were achieved. This was confirmed in Clashach sandstone at 255 bar, when a reduction of 88% in permeability was obtained. Both isolates can survive nutrient starvation, which may improve penetration through the reservoir. Thus, the isolates show potential for field trials in the North Sea as plugging agents.« less

MECHANISMS OF NITROUS OXIDE FORMATION IN COAL FLAMES

EPA Science Inventory

The paper gives results of a study, using both detailed kinetic modeling and plug-flow simulator experiments, to investigate an unknown mechanism by which N2O is formed in coal flames. This mechanism has considerable importance in determining the influence of common and advanced ...

40 CFR 600.308-12 - Fuel economy label format requirements-plug-in hybrid electric vehicles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... significant cause of global warming and smog.” For a, b, c, d, and e, insert the appropriate values... charge the battery as specified in § 600.311. Change the specified voltage if appropriate as specified in...

40 CFR 600.308-12 - Fuel economy label format requirements-plug-in hybrid electric vehicles.

Code of Federal Regulations, 2014 CFR

2014-07-01

... significant cause of global warming and smog.” For a, b, c, d, and e, insert the appropriate values... charge the battery as specified in § 600.311. Change the specified voltage if appropriate as specified in...

40 CFR 600.308-12 - Fuel economy label format requirements-plug-in hybrid electric vehicles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... significant cause of global warming and smog.” For a, b, c, d, and e, insert the appropriate values... charge the battery as specified in § 600.311. Change the specified voltage if appropriate as specified in...

Mercury methylation in sediments of a Brazilian mangrove under different vegetation covers and salinities.

PubMed

de Oliveira, Diana Ciannella Martins; Correia, Raquel Rose Silva; Marinho, Claudio Cardoso; Guimarães, Jean Remy Davée

2015-05-01

The presence and formation of methylmercury (MMHg), a highly toxic form of Hg, in mangrove ecosystems is poorly studied. Therefore the aim of this study was to evaluate mercury methylation potentials in sediment, litter and root samples (Avicennia shaueriana and Spartina alterniflora) from different regions of a mangrove ecosystem, as well as the influence of salinity on methylation. Sediment was sampled under different depths and in mangrove regions with different plant covers and salinities. All samples were incubated with (203)Hg and MM(203)Hg was extracted and measured by liquid scintillation. MMHg was formed in all samples and sites tested including plant roots and litter. Higher Hg methylation was found in the superficial fraction of sediments (0.47-7.82%). Infralittoral sandy sediment had low MMHg formation (0.44-1.61%). Sediment under Rhizophora mangle had lower MMHg formation (0.018-2.23%) than under A. shaueriana (0.2-4.63%) and Laguncularia racemosa (0.08-7.82). MMHg formation in sediment tended to increase with salinity but the differences were not significant. Therefore, MMHg formation occurs in different sites of mangrove ecosystems and may be an important threat that requires further study. Copyright © 2015 Elsevier Ltd. All rights reserved.

Repeated catastrophic valley infill following medieval earthquakes in the Nepal Himalaya.

PubMed

Schwanghart, Wolfgang; Bernhardt, Anne; Stolle, Amelie; Hoelzmann, Philipp; Adhikari, Basanta R; Andermann, Christoff; Tofelde, Stefanie; Merchel, Silke; Rugel, Georg; Fort, Monique; Korup, Oliver

2016-01-08

Geomorphic footprints of past large Himalayan earthquakes are elusive, although they are urgently needed for gauging and predicting recovery times of seismically perturbed mountain landscapes. We present evidence of catastrophic valley infill following at least three medieval earthquakes in the Nepal Himalaya. Radiocarbon dates from peat beds, plant macrofossils, and humic silts in fine-grained tributary sediments near Pokhara, Nepal's second-largest city, match the timing of nearby M > 8 earthquakes in ~1100, 1255, and 1344 C.E. The upstream dip of tributary valley fills and x-ray fluorescence spectrometry of their provenance rule out local sources. Instead, geomorphic and sedimentary evidence is consistent with catastrophic fluvial aggradation and debris flows that had plugged several tributaries with tens of meters of calcareous sediment from a Higher Himalayan source >60 kilometers away. Copyright © 2016, American Association for the Advancement of Science.

Fabrication of pH sensitive nanovalves using smart surface coated nanopores

NASA Astrophysics Data System (ADS)

Nieto-Soto, A. M.; Diaz-Maldonado, D. K.; Rios Angarita, F. A.

2017-01-01

A pH sensitive nanovalve was fabricated using different smart surfaces covalently attached to an anodized aluminium oxide membrane (AAO). The smart surfaces were synthesized using a mixture of aliphatic and aminated silanes. Effect on the contact angle of the aliphatic silane chain length was evaluated. The smart surface, in conjunction with a nanoporous membrane, allowed the formation of a hydrophobic plug which controlled the transport of the molecule safranine depending on the pH of the solution. It was demonstrated that mixtures of butyl and methyl-trimethoxysilane with aminopropyl-trimethoxysilane were able to perform as effective nanovalves creating a plug that remained closed at pH>7 and opened up at pH<5.

Modification of narrow ablating capillaries under the influence of multiple femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Gubin, K. V.; Lotov, K. V.; Trunov, V. I.; Pestryakov, E. V.

2016-09-01

Powerful femtosecond laser pulses that propagate through narrow ablating capillaries cause modification of capillary walls, which is studied experimentally and theoretically. At low intensities, the laser-induced periodic surface structures and porous coating composed of sub-micron particles appear on the walls. At higher intensities, the surface is covered by deposited droplets of the size up to 10 μm. In both cases, the ablated material forms a solid plug that completely blocks the capillary after several hundreds or thousands of pulses. The suggested theoretical model indicates that the plug formation is a universal effect. It must take place in any narrow tube subject to ablation under the action of short laser pulses.

Ex vivo model unravelling cell distribution effect in hydrogels for cartilage repair.

PubMed

Mouser, Vivian H M; Dautzenberg, Noël M M; Levato, Riccardo; van Rijen, Mattie H P; Dhert, Wouter J A; Malda, Jos; Gawlitta, Debby

2018-01-01

The implantation of chondrocyte-laden hydrogels is a promising cartilage repair strategy. Chondrocytes can be spatially positioned in hydrogels and thus in defects, while current clinical cell therapies introduce chondrocytes in the defect depth. The main aim of this study was to evaluate the effect of spatial chondrocyte distribution on the reparative process. To reduce animal experiments, an ex vivo osteochondral plug model was used and evaluated. The role of the delivered and endogenous cells in the repair process was investigated. Full thickness cartilage defects were created in equine osteochondral plugs. Defects were filled with (A) chondrocytes at the bottom of the defect, covered with a cell-free hydrogel, (B) chondrocytes homogeneously encapsulated in a hydrogel, and (C, D) combinations of A and B with different cell densities. Plugs were cultured for up to 57 days, after which the cartilage and repair tissues were characterized and compared to baseline samples. Additionally, at day 21, the origin of cells in the repair tissue was evaluated. Best outcomes were obtained with conditions C and D, which resulted in well-integrated cartilage-like tissue that completely filled the defect, regardless of the initial cell density. A critical role of the spatial chondrocyte distribution in the repair process was observed. Moreover, the osteochondral plugs stimulated cartilage formation in the hydrogels when cultured in the defects. The resulting repair tissue originated from the delivered cells. These findings confirm the potential of the osteochondral plug model for the optimization of the composition of cartilage implants and for studying repair mechanisms.

Volume change associated with formation and dissociation of hydrate in sediment

USGS Publications Warehouse

Ruppel, Carolyn D.; Lee, J.Y.; Santamarina, J. Carlos

2017-01-01

Gas hydrate formation and dissociation in sediments are accompanied by changes in the bulk volume of the sediment and can lead to changes in sediment properties, loss of integrity for boreholes, and possibly regional subsidence of the ground surface over areas where methane might be produced from gas hydrate in the future. Experiments on sand, silts, and clay subject to different effective stress and containing different saturations of hydrate formed from dissolved phase tetrahydrofuran are used to systematically investigate the impact of gas hydrate formation and dissociation on bulk sediment volume. Volume changes in low specific surface sediments (i.e., having a rigid sediment skeleton like sand) are much lower than those measured in high specific surface sediments (e.g., clay). Early hydrate formation is accompanied by contraction for all soils and most stress states in part because growing gas hydrate crystals buckle skeletal force chains. Dilation can occur at high hydrate saturations. Hydrate dissociation under drained, zero lateral strain conditions is always associated with some contraction, regardless of soil type, effective stress level, or hydrate saturation. Changes in void ratio during formation-dissociation decrease at high effective stress levels. The volumetric strain during dissociation under zero lateral strain scales with hydrate saturation and sediment compressibility. The volumetric strain during dissociation under high shear is a function of the initial volume average void ratio and the stress-dependent critical state void ratio of the sediment. Other contributions to volume reduction upon hydrate dissociation are related to segregated hydrate in lenses and nodules. For natural gas hydrates, some conditions (e.g., gas production driven by depressurization) might contribute to additional volume reduction by increasing the effective stress.

Dynamics of the Sediment Plume Over the Yangtze Bank in the Yellow and East China Seas

NASA Astrophysics Data System (ADS)

Luo, Zhifa; Zhu, Jianrong; Wu, Hui; Li, Xiangyu

2017-12-01

A distinct sediment plume exists over the Yangtze Bank in the Yellow and East China Seas (YECS) in winter, but it disappears in summer. Based on satellite color images, there are two controversial viewpoints about the formation mechanism for the sediment plume. One viewpoint is that the sediment plume forms because of cross-shelf sediment advection of highly turbid water along the Jiangsu coast. The other viewpoint is that the formation is caused by local bottom sediment resuspension and diffused to the surface layer through vertical turbulent mixing. The dynamic mechanism of the sediment plume formation has been unclear until now. This issue was explored by using a numerical sediment model in the present paper. Observed wave, current, and sediment data from 29 December 2016 to 16 January 2017 were collected near the Jiangsu coast and used to validate the model. The results indicated that the model can reproduce the hydrodynamic and sediment processes. Numerical experiments showed that the bottom sediment could be suspended by the bottom shear stress and diffuse to the surface layer by vertical mixing in winter; however, the upward diffusion is restricted by the strong stratification in summer. The sediment plume is generated locally due to bottom sediment resuspension primarily via tide-induced bottom shear stress rather than by cross-shelf sediment advection over the Yangtze Bank.

The filling of powdered herbs into two-piece hard capsules using hydrogenated cotton seed oil as lubricant.

PubMed

Aling, Joanna; Podczeck, Fridrun

2012-11-20

The aim of this work was to investigate the plug formation and filling properties of powdered herbal leaves using hydrogenated cotton seed oil as an alternative lubricant. In a first step, unlubricated and lubricated herbal powders were studied on a small scale using a plug simulator, and low-force compression physics and parameterization techniques were used to narrow down the range in which the optimum amount of lubricant required would be found. In a second step these results were complemented with investigations into the flow properties of the powders based on packing (tapping) experiments to establish the final optimum lubricant concentration. Finally, capsule filling of the optimum formulations was undertaken using an instrumented tamp filling machine. This work has shown that hydrogenated cotton seed oil can be used advantageously for the lubrication of herbal leaf powders. Stickiness as observed with magnesium stearate did not occur, and the optimum lubricant concentration was found to be less than that required for magnesium stearate. In this work, lubricant concentrations of 1% or less hydrogenated cotton seed oil were required to fill herbal powders into capsules on the instrumented tamp-filling machine. It was found that in principle all powders could be filled successfully, but that for some powders the use of higher compression settings was disadvantageous. Relationships between the particle size distributions of the powders, their flow and consolidation as well as their filling properties could be identified by multivariate statistical analysis. The work has demonstrated that a combination of the identification of plug formation and powder flow properties is helpful in establishing the optimum lubricant concentration required using a small quantity of powder and a powder plug simulator. On an automated tamp-filling machine, these optimum formulations produced satisfactory capsules in terms of coefficient of fill weight variability and capsule weight. Copyright © 2012 Elsevier B.V. All rights reserved.

IMPROVED WELL PLUGGING EQUIPMENT AND WASTE MANGEMENT TECHNIQUES EXCEED ALARA GOALS AT THE OAK RIDGE NATIONAL LABORATORY

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

Whiteside, R.; Pawlowicz, R.; Whitehead, L.

2002-02-25

In 2000, Bechtel Jacobs Company LLC (BJC) contracted Tetra Tech NUS, Inc. (TtNUS) and their sub-contractor, Texas World Operations, Inc. (TWO), to plug and abandon (P&A) 111 wells located in the Melton Valley area of Oak Ridge National Laboratory (ORNL). One hundred and seven of those wells were used to monitor fluid movement and subsurface containment of the low level radioactive liquid waste/grout slurry that was injected into the Pumpkin Valley Shale Formation, underlying ORNL. Four wells were used as hydrofracture injection wells to emplace the waste in the shale formation. Although the practice of hydrofracturing was and is consideredmore » by many to pose no threat to human health or the environment, the practice was halted in 1982 after the Federal Underground Injection Control regulations were enacted by United States Environmental Protection Agency (USEPA) making it necessary to properly close the wells. The work is being performed for the United States Department of Energy Oak Ridge Operations (DOE ORO). The project team is using the philosophy of minimum waste generation and the principles of ALARA (As Low As Reasonably Achievable) as key project goals to minimize personnel and equipment exposure, waste generation, and project costs. Achievement of these goals was demonstrated by the introduction of several new pieces of custom designed well plugging and abandonment equipment that were tested and used effectively during field operations. Highlights of the work performed and the equipment used are presented.« less

Methyl tert butyl ether is anti-angiogenic in both in vitro and in vivo mammalian model systems.

PubMed

Kozlosky, John; Bonventre, Josephine; Cooper, Keith

2013-08-01

Methyl-tertiary butyl ether (MTBE), a well known gasoline oxygenate, and US Food and Drug Administration approved gallstone treatment, has been previously shown to specifically target teleost embryonic angiogenesis. The studies reported here were to determine whether similar vascular disrupting effects occur in higher vertebrate models. Rat brain endothelial cells were isolated and allowed to form microcapillary-like tubes on Matrigel. MTBE (0.34-34.0 mm) exposure resulted in a dose-dependent reduction of tube formation, with the LOAEL at 0.34 mm, while MTBE's primary metabolite, tertiary butyl alcohol had no effect on tube formation. HUVECs, a primary cell line representing macrovascular cells, were able to form tubes on Matrigel in the presence of MTBE (1.25-80 mm), but the tubes were narrower than those formed in the absence of MTBE. In a mouse Matrigel plug implantation assay, 34.0 mm MTBE completely inhibited vessel invasion into plugs containing endothelial cell growth supplement (ECGS) compared with control plugs with ECGS alone. When timed-pregnant Fisher 344 rats were gavaged with MTBE (500-1500 mg kg(-1) ) from day 6 of organogenesis through 10 days post-parturition, no organ toxicity or histological changes in pup vasculature were observed. Results of the in vitro cell culture studies show that MTBE is anti-angiogenic at mm concentrations and has potential use as an anti-angiogenic treatment for solid tumors with minimal toxicity. Copyright © 2012 John Wiley & Sons, Ltd.

Plug into PR. NJLA Public Relations Handbook.

ERIC Educational Resources Information Center

New Jersey Library Association, Trenton.

A guide to using public relations techniques to promote both everyday services and special events at libraries, this handbook describes and suggests ways to use library displays; in-house printing; the local media, e.g., radio spots and cable television; library programs; marketing and promotion; and fundraising, including the formation of a…

7 CFR 3201.25 - 2-Cycle engine oils.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 15 2012-01-01 2012-01-01 false 2-Cycle engine oils. 3201.25 Section 3201.25... Designated Items § 3201.25 2-Cycle engine oils. (a) Definition. Lubricants designed for use in 2-cycle engines to provide lubrication, decreased spark plug fouling, reduced deposit formation, and/or reduced...

7 CFR 3201.25 - 2-Cycle engine oils.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false 2-Cycle engine oils. 3201.25 Section 3201.25... Designated Items § 3201.25 2-Cycle engine oils. (a) Definition. Lubricants designed for use in 2-cycle engines to provide lubrication, decreased spark plug fouling, reduced deposit formation, and/or reduced...

7 CFR 3201.25 - 2-Cycle engine oils.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false 2-Cycle engine oils. 3201.25 Section 3201.25... Designated Items § 3201.25 2-Cycle engine oils. (a) Definition. Lubricants designed for use in 2-cycle engines to provide lubrication, decreased spark plug fouling, reduced deposit formation, and/or reduced...

Formation of banded vegetation patterns resulted from interactions between sediment deposition and vegetation growth.

PubMed

Huang, Tousheng; Zhang, Huayong; Dai, Liming; Cong, Xuebing; Ma, Shengnan

2018-03-01

This research investigates the formation of banded vegetation patterns on hillslopes affected by interactions between sediment deposition and vegetation growth. The following two perspectives in the formation of these patterns are taken into consideration: (a) increased sediment deposition from plant interception, and (b) reduced plant biomass caused by sediment accumulation. A spatial model is proposed to describe how the interactions between sediment deposition and vegetation growth promote self-organization of banded vegetation patterns. Based on theoretical and numerical analyses of the proposed spatial model, vegetation bands can result from a Turing instability mechanism. The banded vegetation patterns obtained in this research resemble patterns reported in the literature. Moreover, measured by sediment dynamics, the variation of hillslope landform can be described. The model predicts how treads on hillslopes evolve with the banded patterns. Thus, we provide a quantitative interpretation for coevolution of vegetation patterns and landforms under effects of sediment redistribution. Copyright © 2018. Published by Elsevier Masson SAS.

An In situ Study of Seasonal Dissolved Organic Carbon and Nutrient Fluxes from a Spartina alterniflora Salt Marsh in North Carolina

NASA Astrophysics Data System (ADS)

Detweiler, D. J.; Loh, A. N.

2016-02-01

Spartina alterniflora salt marshes are among the most productive and biogeochemically active ecosystems on Earth. While they have been shown to be sources of dissolved organic carbon (DOC) and nutrient export to the coastal ocean via tidal processes, it has not been well quantified experimentally. The purpose of this study was to quantify DOC and nutrient fluxes from a fringing S. alterniflora salt marsh in North Carolina. The experiment was conducted using in situ benthic microcosm chambers filled with seawater during a flooding tide; the chambers were then plugged, and samples were collected during an ebbing tide over the course of 270 minutes while simulating light and dark conditions. Water samples were filtered and analyzed for DOC and nutrient concentrations over time and used to calculate fluxes from vegetated (S. alterniflora) and non-vegetated marsh sediments. Preliminary daily flux calculations show that fluxes from vegetated sediments have a higher magnitude when compared to fluxes from non-vegetated sediments. Daily flux calculations also suggest that vegetated sediments act as a DOC source while non-vegetated sediments act as a DOC sink. Additional flux data for dissolved inorganic and organic nitrogen (DIN, DON) and dissolved inorganic and organic phosphorus (DIP, DOP) as well as marsh sediment characterization will also be presented. Ultimately, these data will provide seasonal daily flux calculations for S. alterniflora salt marshes and insight as to how changing environmental conditions such as wetland modification, wetland destruction, nutrient input, and climate change are affecting coastal biogeochemical cycles.

A Proposed Information Architecture for Telehealth System Interoperability

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

Craft, R.L.; Funkhouser, D.R.; Gallagher, L.K.

1999-04-20

We propose an object-oriented information architecture for telemedicine systems that promotes secure `plug-and-play' interaction between system components through standardized interfaces, communication protocols, messaging formats, and data definitions. In this architecture, each component functions as a black box, and components plug together in a ''lego-like'' fashion to achieve the desired device or system functionality. Introduction Telemedicine systems today rely increasingly on distributed, collaborative information technology during the care delivery process. While these leading-edge systems are bellwethers for highly advanced telemedicine, most are custom-designed and do not interoperate with other commercial offerings. Users are limited to a set of functionality that amore » single vendor provides and must often pay high prices to obtain this functionality, since vendors in this marketplace must deliver en- tire systems in order to compete. Besides increasing corporate research and development costs, this inhibits the ability of the user to make intelligent purchasing decisions regarding best-of-breed technologies. This paper proposes a reference architecture for plug-and-play telemedicine systems that addresses these issues.« less

Unplugging the callose plug from sieve pores.

PubMed

Xie, Bo; Hong, Zonglie

2011-04-01

The presence of callose in sieve plates has been known for a long time, but how this polysaccharide plug is synthesized has remained unsolved. Two independent laboratories have recently reported the identification of callose synthase 7 (CalS7), also known as glucan synthase-like 7 (GSL7), as the enzyme responsible for callose deposition in sieve plates. Mutant plants defective in this enzyme failed to synthesize callose in developing sieve plates during phloem formation and were unable to accumulate callose in sieve pores in response to stress treatments. The mutant plants developed less open pores per sieve plate and the pores were smaller in diameter. As a result, phloem conductivity was reduced significantly and the mutant plants were shorter and set fewer seeds.

An evaluation of smear layer with various desensitizing agents after tooth preparation.

PubMed

Zaimoglu, A; Aydin, A K

1992-09-01

According to hydrodynamics, any agent blocking the dentinal tubules reduces the flow of fluids and diminishes hypersensitivity. The properties of the desensitizing agents that sponsor tubular occlusion and the barrier efficiency resulting from the interaction of the smear layer with test materials were examined with the scanning electron microscope and energy-dispersive x-ray microanalysis. Selected dentinal desensitizing was accomplished with burnishing procedures, cavity varnish, calcium hydroxide, and topical fluoride. Subjective evaluations were also recorded clinically after tooth preparation. This investigation indicated that the smear layer did not protect against zinc phosphate cement, and that cavity varnish prevented the formation of the smear plugs. The smear layer and plugs were basically composed of calcium and phosphorus, the major ingredients of dentin.

Unplugging the callose plug from sieve pores

PubMed Central

Xie, Bo

2011-01-01

The presence of callose in sieve plates has been known for a long time, but how this polysaccharide plug is synthesized has remained unsolved. Two independent laboratories have recently reported the identification of callose synthase 7 (CalS7), also known as glucan synthase-like 7 (GSL7), as the enzyme responsible for callose deposition in sieve plates. Mutant plants defective in this enzyme failed to synthesize callose in developing sieve plates during phloem formation and were unable to accumulate callose in sieve pores in response to stress treatments. The mutant plants developed less open pores per sieve plate and the pores were smaller in diameter. As a result, phloem conductivity was reduced significantly and the mutant plants were shorter and set fewer seeds. PMID:21386663

Direct synthesis of Al-SBA-15 containing aluminosilicate species plugs in an acid-free medium and structural adjustment by hydrothermal post-treatment

NASA Astrophysics Data System (ADS)

Shi, Lei; Xu, Yan; Zhang, Na; Lin, Sen; Li, Xiangping; Guo, Peng; Li, Xuebing

2013-07-01

A series of Al-SBA-15 with controllable aluminosilicate plug structures inside straight mesopores has been hydrothermally synthesized in a one-step synthesis in an environmentally friendly acid-free medium, using triblock copolymer Pluronic P123 as a structure-directing agent, water as solvent, tetraethyl orthosilicate (TEOS) and aluminum nitrate (Al(NO)3·9H2O) as silica and aluminum sources, respectively. The effects of the P123/Si molar ratio in the initial solution and aging temperature on the structural properties of the resulting materials were investigated by powder X-ray diffraction (XRD), nitrogen adsorption-desorption at 77 K, transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric (TG), FT-IR spectra and inductively coupled plasma (ICP) analyses. The nature of the Al species and the acidity of the resultant samples were studied by solid state 27Al MAS NMR and pyridine adsorption measurements. The specific surface area (935-755 m2g-1), pore volume (1.03-0.56 cm3g-1) and especially the concentration and distribution of open type mesopores (0-68% to the total pores) of the synthesized Al-SBA-15 can be controlled by a simple adjustment of the P123/Si molar ratio in the initial solution. Moreover, increasing the aging temperature higher than 363 K can remarkably decrease the formation of plug structures to obtain “open” form mesopores. The observation by TEM of alternate defined gray and white areas inside the mesopores gives the strong evidence of isolated microporous aluminosilicate plugs inside the channels. In addition, a moderate hydrothermal post-treatment can finely modify the mesostructures through the partial or complete dissolution of the aluminosilicate plugs.

Molecular basis of usher pore gating in Escherichia coli pilus biogenesis.

PubMed

Volkan, Ender; Kalas, Vasilios; Pinkner, Jerome S; Dodson, Karen W; Henderson, Nadine S; Pham, Thieng; Waksman, Gabriel; Delcour, Anne H; Thanassi, David G; Hultgren, Scott J

2013-12-17

Extracellular fibers called chaperone-usher pathway pili are critical virulence factors in a wide range of Gram-negative pathogenic bacteria that facilitate binding and invasion into host tissues and mediate biofilm formation. Chaperone-usher pathway ushers, which catalyze pilus assembly, contain five functional domains: a 24-stranded transmembrane β-barrel translocation domain (TD), a β-sandwich plug domain (PLUG), an N-terminal periplasmic domain, and two C-terminal periplasmic domains (CTD1 and 2). Pore gating occurs by a mechanism whereby the PLUG resides stably within the TD pore when the usher is inactive and then upon activation is translocated into the periplasmic space, where it functions in pilus assembly. Using antibiotic sensitivity and electrophysiology experiments, a single salt bridge was shown to function in maintaining the PLUG in the TD channel of the P pilus usher PapC, and a loop between the 12th and 13th beta strands of the TD (β12-13 loop) was found to facilitate pore opening. Mutation of the β12-13 loop resulted in a closed PapC pore, which was unable to efficiently mediate pilus assembly. Deletion of the PapH terminator/anchor resulted in increased OM permeability, suggesting a role for the proper anchoring of pili in retaining OM integrity. Further, we introduced cysteine residues in the PLUG and N-terminal periplasmic domains that resulted in a FimD usher with a greater propensity to exist in an open conformation, resulting in increased OM permeability but no loss in type 1 pilus assembly. These studies provide insights into the molecular basis of usher pore gating and its roles in pilus biogenesis and OM permeability.

Formation Mechanisms for Spur and Groove Features on Fringing Reefs

NASA Astrophysics Data System (ADS)

Bramante, J. F.; Ashton, A. D.; Perron, J. T.

2016-12-01

Spur and groove systems (SAGs) are ubiquitous morphological features found on fore-reef slopes globally. SAGs consist of parallel, roughly shore-normal ridges of actively growing coral and coralline algae (spurs) separated by offshore-sloping depressions typically carpeted by a veneer of sediment (grooves). Although anecdotal observations and recent statistical analyses have reported correlations between wave exposure and the distribution of SAGs on fore-reef slopes, the physical mechanisms driving SAG formation remain poorly understood. For example, there remains significant debate regarding the importance of coral growth versus bed erosion for SAG formation. Here we investigate a hypothesis that SAG formation is controlled by feedbacks between sediment production and diffusion and coral growth. Using linear stability analysis, we find that sediment production, coral growth, and the feedbacks between them are unable to produce stable periodic structures without a sediment sink. However, if incipient grooves act as conduits for sediment transport offshore, a positive feedback can develop as the groove bed erodes through wave-driven abrasion during offshore transport. Eventually a negative feedback slows groove deepening when the groove bed is armored by sediment, and the groove bed relaxes to a sediment-veneered equilibrium profile analogous to sediment-rich shorefaces. To test this hypothesis, we apply a numerical model that incorporates coral growth and sediment production, sediment diffusion, non-linear wave-driven abrasion, and sediment advection offshore. This model produces the periodic, linear features characteristic of SAG morphology. The relative magnitude of growth, production, diffusion, abrasion, and advection rates affect periodic spacing or wavelength of the modeled SAGs. Finally, we evaluate the ability of the model to replicate geographical variability in SAG characteristics using previously published datasets and reanalysis wave data.

Numerical model of frazil ice and suspended sediment concentrations and formation of sediment laden ice in the Kara Sea

USGS Publications Warehouse

Sherwood, C.R.

2000-01-01

A one-dimensional (vertical) numerical model of currents, mixing, frazil ice concentration, and suspended sediment concentration has been developed and applied in the shallow southeastern Kara Sea. The objective of the calculations is to determine whether conditions suitable for turbid ice formation can occur during times of rapid cooling and wind- and wave-induced sediment resuspension. Although the model uses a simplistic approach to ice particles and neglects ice-sediment interactions, the results for low-stratification, shallow (∼20-m) freeze-up conditions indicate that the coconcentrations of frazil ice and suspended sediment in the water column are similar to observed concentrations of sediment in turbid ice. This suggests that wave-induced sediment resuspension is a viable mechanism for turbid ice formation, and enrichment mechanisms proposed to explain the high concentrations of sediment in turbid ice relative to sediment concentrations in underlying water may not be necessary in energetic conditions. However, salinity stratification found near the Ob' and Yenisey Rivers damps mixing between ice-laden surface water and sediment-laden bottom water and probably limits incorporation of resuspended sediment into turbid ice until prolonged or repeated wind events mix away the stratification. Sensitivity analyses indicate that shallow (≤20 m), unstratified waters with fine bottom sediment (settling speeds of ∼1 mm s−1 or less) and long open water fetches (>25 km) are ideal conditions for resuspension.

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

Gustavson, T.C.; Holliday, V.T.

Eolian sediments have accumulated as non-glacigenic loess and thin sand sheets on the Central and Southern High Plains grasslands of Texas and new mexico since the late Miocene. Locally as much as 110 m of eolian sediments with numerous paleosols are preserved in the Quaternary Blackwater Draw formation and the upper part of the Miocene-Pleiocene Ogallala formation. These sediments and paleosols, which cover more than 130,000 km{sup 2}, are similar to recent surface sediments and soils and record a long period of episodic eolian transport and sedimentation, and pedogenesis on a stable low-relief grass-covered landscape. Eolian sections, which comprise themore » fine sand to coarse silt lithofacies of the Ogallala formation, and the very fine to fine sand and sandy mud lithofacies of the Blackwater Draw formation, generally lack primary sedimentary structures. Grain size of Ogallala sediments decreases from west to east and grain size of Blackwater Draw sediments decreases from southwest to northeast. Soil horizonation is well developed in most sections, and buried calcic and argillic horizons are common. Calcic horizons are characterized by sharply increased CaCO{sub 3} content in the form of filaments, nodules, and petrocalcic horizons (calcretes). Argillic horizons are characterized by increased illuvial clay, pedogenic structure, and darker reddish hues. Rhizocretions are common locally. Open root tubules, which are typically less than 1 mm in diameter and characteristic of small plants like grasses, are present in all Ogallala and Blackwater Draw eolian sediments. Paleosols preserved in eolian sediments of the High Plains reflect periods of sedimentation followed by episodes of landscape stability and pedogenesis, and negligible sedimentation. Episodes of sedimentation and soil development likely resulted from cyclic decreases and increases in available moisture and vegetative cover. Eolian sediments were eroded and transported eastward during dry periods when vegetation was sparse in source areas, such as the western High Plains and the Pecos Valley. During humid periods more abundant vegetation probably protected source areas from deflation, and resulted in landscape stability across the High Plains.« less

Friction pull plug welding: chamfered heat sink pull plug design

NASA Technical Reports Server (NTRS)

Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

2002-01-01

Friction Pull Plug Welding (FPPW) is a solid state repair process for defects up to one inch in length, only requiring single sided tooling (OSL) for usage on flight hardware. Experimental data has shown that the mass of plug heat sink remaining above the top of the plate surface after a weld is completed (the plug heat sink) affects the bonding at the plug top. A minimized heat sink ensures complete bonding of the plug to the plate at the plug top. However, with a minimal heat sink three major problems can arise, the entire plug could be pulled through the plate hole, the central portion of the plug could be separated along grain boundaries, or the plug top hat can be separated from the body. The Chamfered Heat Sink Pull Plug Design allows for complete bonding along the ISL interface through an outside diameter minimal mass heat sink, while maintaining enough central mass in the plug to prevent plug pull through, central separation, and plug top hat separation.

Rapid formation of hyperpycnal sediment gravity currents offshore of a semi-arid California river

USGS Publications Warehouse

Warrick, J.A.; Xu, Jie; Noble, M.A.; Lee, H.J.

2008-01-01

Observations of sediment dispersal from the Santa Clara River of southern California during two moderately sized river discharge events suggest that river sediment rapidly formed a negatively buoyant (hyperpycnal) bottom plume along the seabed within hours of peak discharge. An array of acoustic and optical sensors were placed at three stations 1 km from the Santa Clara River mouth in 10-m water depth during January-February 2004. These combined observations suggest that fluid mud concentrations of suspended sediment (>10 g/l) and across-shore gravity currents (???5 cm/s) were observed in the lower 20-40 cm of the water column 4-6 h after discharge events. Gravity currents were wave dominated, rather than auto-suspending, and appeared to consist of silt-to-clay sized sediment from the river. Sediment mass balances suggest that 25-50% of the discharged river sediment was transported by these hyperpycnal currents. Sediment settling purely by flocs (???1 mm/s) cannot explain the formation of the observed hyperpycnal plumes, therefore we suggest that some enhanced sediment settling from mixing, convective instabilities, or diverging plumes occurred that would explain the formation of the gravity currents. These combined results provide field evidence that high suspended-sediment concentrations from rivers (>1 g/l) may rapidly form hyperpycnal sediment gravity currents immediately offshore of river mouths, and these pathways can explain a significant portion of the river-margin sediment budget. The fate of this sediment will be strongly influenced by bathymetry, whereas the fate of the remaining sediment will be much more influenced by ocean currents.

Press-fit stability of an osteochondral autograft: Influence of different plug length and perfect depth alignment.

PubMed

Kock, Niels B; Van Susante, Job L C; Buma, Pieter; Van Kampen, Albert; Verdonschot, Nico

2006-06-01

Osteochondral autologous transplantation is used for the treatment of full-thickness articular cartilage lesions of a joint. Press-fit stability is an important factor for good survival of the transplanted plugs. 36 plugs of three different lengths were transplanted in fresh-frozen human knees. On one condyle, 3 plugs were exactly matched to the depth of the recipient site ("bottomed" plugs) and on the opposite condyle 3 plugs were 5 mm shorter than the depth of the recipient site ("unbottomed" plugs). Plugs were left protruding and then pushed in until flush, and then to 2 mm below flush level, using a loading apparatus. Longer plugs needed higher forces to begin displacement. At flush level, bottomed plugs needed significantly higher forces than unbottomed plugs to become displaced below flush level (mean forces of 404 N and 131 N, respectively). Shorter bottomed plugs required higher forces than longer bottomed ones. Bottomed plugs generally provide much more stability than unbottomed ones. Short bottomed plugs are more stable than long bottomed plugs. Thus, in clinical practice it is advisable to use short bottomed plugs. If, however, unbottomed plugs are still chosen, the longer the plug the higher the resulting stability will be because of higher frictional forces.

25 CFR 226.32 - Well records and reports.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 25 Indians 1 2014-04-01 2014-04-01 false Well records and reports. 226.32 Section 226.32 Indians... LANDS FOR OIL AND GAS MINING Requirements of Lessees § 226.32 Well records and reports. (a) Lessee shall..., plugging, or abandonment of all wells. These records shall show all the formations penetrated, the content...

25 CFR 226.32 - Well records and reports.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 25 Indians 1 2012-04-01 2011-04-01 true Well records and reports. 226.32 Section 226.32 Indians... LANDS FOR OIL AND GAS MINING Requirements of Lessees § 226.32 Well records and reports. (a) Lessee shall..., plugging, or abandonment of all wells. These records shall show all the formations penetrated, the content...

25 CFR 226.32 - Well records and reports.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 25 Indians 1 2013-04-01 2013-04-01 false Well records and reports. 226.32 Section 226.32 Indians... LANDS FOR OIL AND GAS MINING Requirements of Lessees § 226.32 Well records and reports. (a) Lessee shall..., plugging, or abandonment of all wells. These records shall show all the formations penetrated, the content...

Deflagration-to-detonation transition in granular HMX

NASA Technical Reports Server (NTRS)

Campbell, A. W.

1980-01-01

Granular HMX of three degrees of fineness was packed into heavy-walled steel tubes closed at both ends. Ignition was obtained at one end using an intimate mixture of finely divided titanium and boron as an igniter that produced heat with little gas. The distance to detonation was determined by examination of the resulting tube fragments. By inserting tightly-fitted neoprene diaphragms periodically into the HMX column, it was shown that the role of convective combustion was limited to the initial stage of the deflagration to detonation (DDT) process. Experiments in which various combinations of two of the three types of HMX were loaded into the same tube showed that heating by adiabatic shear of explosive grains was an essential factor in the final buildup to detonation. A description of the DDT process is developed in which conductive burning is followed in turn by convective burning, bed collapse with plug formation, onset of accelerated burning at the front of the plug through heating by intercrystalline friction and adiabatic shear, and intense shock formation resulting in high-order detonation.

Threshold of microvascular occlusion: injury size defines the thrombosis scenario.

PubMed

Belyaev, Aleksey V; Panteleev, Mikhail A; Ataullakhanov, Fazly I

2015-07-21

Damage to the blood vessel triggers formation of a hemostatic plug, which is meant to prevent bleeding, yet the same phenomenon may result in a total blockade of a blood vessel by a thrombus, causing severe medical conditions. Here, we show that the physical interplay between platelet adhesion and hemodynamics in a microchannel manifests in a critical threshold behavior of a growing thrombus. Depending on the size of injury, two distinct dynamic pathways of thrombosis were found: the formation of a nonocclusive plug, if injury length does not exceed the critical value, and the total occlusion of the vessel by the thrombus otherwise. We develop a mathematical model that demonstrates that switching between these regimes occurs as a result of a saddle-node bifurcation. Our study reveals the mechanism of self-regulation of thrombosis in blood microvessels and explains experimentally observed distinctions between thrombi of different physical etiology. This also can be useful for the design of platelet-aggregation-inspired engineering solutions. Copyright © 2015 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Methane Recovery from Hydrate-bearing Sediments

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

J. Carlos Santamarina; Costas Tsouris

2011-04-30

Gas hydrates are crystalline compounds made of gas and water molecules. Methane hydrates are found in marine sediments and permafrost regions; extensive amounts of methane are trapped in the form of hydrates. Methane hydrate can be an energy resource, contribute to global warming, or cause seafloor instability. This study placed emphasis on gas recovery from hydrate bearing sediments and related phenomena. The unique behavior of hydrate-bearing sediments required the development of special research tools, including new numerical algorithms (tube- and pore-network models) and experimental devices (high pressure chambers and micromodels). Therefore, the research methodology combined experimental studies, particle-scale numerical simulations,more » and macro-scale analyses of coupled processes. Research conducted as part of this project started with hydrate formation in sediment pores and extended to production methods and emergent phenomena. In particular, the scope of the work addressed: (1) hydrate formation and growth in pores, the assessment of formation rate, tensile/adhesive strength and their impact on sediment-scale properties, including volume change during hydrate formation and dissociation; (2) the effect of physical properties such as gas solubility, salinity, pore size, and mixed gas conditions on hydrate formation and dissociation, and it implications such as oscillatory transient hydrate formation, dissolution within the hydrate stability field, initial hydrate lens formation, and phase boundary changes in real field situations; (3) fluid conductivity in relation to pore size distribution and spatial correlation and the emergence of phenomena such as flow focusing; (4) mixed fluid flow, with special emphasis on differences between invading gas and nucleating gas, implications on relative gas conductivity for reservoir simulations, and gas recovery efficiency; (5) identification of advantages and limitations in different gas production strategies with emphasis; (6) detailed study of CH4-CO2 exchange as a unique alternative to recover CH4 gas while sequestering CO2; (7) the relevance of fines in otherwise clean sand sediments on gas recovery and related phenomena such as fines migration and clogging, vuggy structure formation, and gas-driven fracture formation during gas production by depressurization.« less

A review of biostratigraphic studies in the olistostrome deposits of Karangsambung Formation

NASA Astrophysics Data System (ADS)

Hendrizan, Marfasran

2018-02-01

Planktonic foraminifera is widely used for marine sediment biostratigraphy. Foraminiferal biostratigraphy of Karangsambung Formation is relatively rare to be investigated by previous researchers. A review of foraminiferal biostratigraphy is expected to be early work to perform a research about the ages of Tertiary rock formations in Karangsambung. The research area is formed by olistostrome process; a sedimentary slide deposit characterized by bodies of harder rock mixed and dispersed in a matrix. Biostratigraphic studies based on foraminifera and nannoplankton in Karangsambung Formation are still qualitative analysis using fossils biomarker. However, the age of this formation is still debatable based on foraminifera and nannofossil analysis. Two explanations of debatable ages in Karangsambung Formation that is possibly developed in Karangsambung area: firstly, Karangsambung Formation is characterized by normal sedimentation in some places and other regions such Kali Welaran and Clebok, Village as a product of olistostrome, and secondly, Karangsambung Formation is olistostrome deposit. However, micropaleontology sampling and analysis in matrix clays from olistostrome were ignored causing biostratigraphical results in those matrix clays occurred in normal sedimentation process and achieving the age of middle Eocene to Oligocene. We suppose previous authors picked samples in matrix of Karangsambung Formation from several river sections, which will make misinterpretation of the age of Karangsambung Formation. The age of middle to late Eocene probably is the dates of the older sediment that was reworked by sliding and sampling process and accumulated in Karangsambung Formation. The date of Karangsambung Fm is in Oligocene period based on a finding of several calcareous nannofossils. Detailed micropaleontological analysis of olistostrome deposits in Karangsambung Formation should be reevaluated for new finding of the accurate dating. Re-evaluation should start from detailed sedimentological mapping of Karangsambung Fm transects based on previous authors especially Kali Welaran, Jatibungkus transect and Clebok section followed by systematic sampling of normal sedimentation process from olistostrome products and matrix clays of olistostrome Karangsambung Formation. Finally, quantitative method of micropaleontological analysis can be applied to identify the age of Karangsambung Formation.

Assessment of Regeneration of Bone in the Extracted Third Molar Sockets Augmented Using Xenograft (CollaPlugTN Zimmer) in Comparison with the Normal Healing on the Contralateral Side.

PubMed

Ranganathan, Murugan; Balaji, M; Krishnaraj, R; Narayanan, Vivek; Thangavelu, Annamalai

2017-11-01

Alveolar bone resorption is a significant clinical problem. Bone loss in third molar region following extraction or surgical removal not only leads to periodontal problems in second molar region but also it may lead to some serious problems like increased incidence of angle fractures. In order to reduce the risks following third molar surgery, the socket should be augmented with bone grafts. In recent days guided tissue regeneration is the most accepted and successful technique followed many authors and its efficacy has been proved. Based upon our clinical experience, the use of bio absorbable collagen wound dressing such as CollaPlug TN has achieved quick healing and more primary wound coverage. Amongst the graft materials collagen is preferable due to its high biocompatibility and hemostatic ability. This study was done to assess the regeneration of bone in the extracted third molar sockets using xenograft (CollaPlug TN -Zimmer) which was compared with the normal healing on the contra lateral side. The assessment was done to analyze post-operative healing complications and to compare the bone density formed between control site and implant site radiologically. On this basis of this study, the use of collaplugTN appears to be beneficial to the patient in postoperative wound healing and also for better bone formation. The use of this material was advantageous because of its simplicity of application cost effectiveness and availability. There is enhanced wound healing and early bone formation.

Clay mineralogy, strontium and neodymium isotope ratios in the sediments of two High Arctic catchments (Svalbard)

NASA Astrophysics Data System (ADS)

Hindshaw, Ruth S.; Tosca, Nicholas J.; Piotrowski, Alexander M.; Tipper, Edward T.

2018-03-01

The identification of sediment sources to the ocean is a prerequisite to using marine sediment cores to extract information on past climate and ocean circulation. Sr and Nd isotopes are classical tools with which to trace source provenance. Despite considerable interest in the Arctic Ocean, the circum-Arctic source regions are poorly characterised in terms of their Sr and Nd isotopic compositions. In this study we present Sr and Nd isotope data from the Paleogene Central Basin sediments of Svalbard, including the first published data of stream suspended sediments from Svalbard. The stream suspended sediments exhibit considerable isotopic variation (ɛNd = -20.6 to -13.4; 87Sr / 86Sr = 0.73421 to 0.74704) which can be related to the depositional history of the sedimentary formations from which they are derived. In combination with analysis of the clay mineralogy of catchment rocks and sediments, we suggest that the Central Basin sedimentary rocks were derived from two sources. One source is Proterozoic sediments derived from Greenlandic basement rocks which are rich in illite and have high 87Sr / 86Sr and low ɛNd values. The second source is Carboniferous to Jurassic sediments derived from Siberian basalts which are rich in smectite and have low 87Sr / 86Sr and high ɛNd values. Due to a change in depositional conditions throughout the Paleogene (from deep sea to continental) the relative proportions of these two sources vary in the Central Basin formations. The modern stream suspended sediment isotopic composition is then controlled by modern processes, in particular glaciation, which determines the present-day exposure of the formations and therefore the relative contribution of each formation to the stream suspended sediment load. This study demonstrates that the Nd isotopic composition of stream suspended sediments exhibits seasonal variation, which likely mirrors longer-term hydrological changes, with implications for source provenance studies based on fixed end-members through time.

Modeling of Hydrate Formation Mode in Raw Natural Gas Air Coolers

NASA Astrophysics Data System (ADS)

Scherbinin, S. V.; Prakhova, M. Yu; Krasnov, A. N.; Khoroshavina, E. A.

2018-05-01

Air cooling units (ACU) are used at all the gas fields for cooling natural gas after compressing. When using ACUs on raw (wet) gas in a low temperature condition, there is a danger of hydrate plug formation in the heat exchanging tubes of the ACU. To predict possible hydrate formation, a mathematical model of the air cooler thermal behavior used in the control system shall adequately calculate not only gas temperature at the cooler's outlet, but also a dew point value, a temperature at which condensation, as well as the gas hydrate formation point, onsets. This paper proposes a mathematical model allowing one to determine the pressure in the air cooler which makes hydrate formation for a given gas composition possible.

Closing the Gaps in Offshore P&A: Lessons Learned From the North Sea

NASA Astrophysics Data System (ADS)

Torsater, M.

2017-12-01

This talk will give an overview of the major challenges related to offshore well plugging and abandonment (P&A) with examples from the North Sea. The talk will outline why today's P&A operations are so time consuming and expensive, and it will point out current technology gaps and issues related to standards and regulations in the North Sea countries. Emerging P&A solutions will be discussed, and results from large ongoing research projects in Norway will be shared. Special emphasis will be given to promising new concepts, such as using creeping shale formations as permanent well barriers, and using thermal methods for removal of tubing and casing. The long-term aspects of well plugging will also be discussed, together with methods available for minimizing leakage risk.

Holocene Evolution and Sediment Provenance of Horn Island, Mississippi, USA

NASA Astrophysics Data System (ADS)

Schulze, N.; Wallace, D. J.; Miner, M. D.

2017-12-01

As one of the most stable islands in the Mississippi-Alabama barrier island chain, Horn Island provides critical habitat, plays an important role in regulating estuarine conditions in the Mississippi Sound, and helps to attenuate wave energy and storm surge for the mainland. The provenance of sediments comprising Horn Island is largely unknown and has implications for mode of island genesis and evolution. The existing literature proposes that island chain formation was initiated by bar emergence from a subaqueous spit that grew laterally westward from Dauphin Island in the east. Decelerating sea level rise 4,000 to 5,000 years ago facilitated island formation. This proposed mode of formation is supported by a lone radiocarbon date from lagoonal sediments below Horn Island, suggesting the system formed after 4,615 ± 215 years BP. Rivers supplying suspended sediment include the Mississippi, Pascagoula, Mobile and Apalachicola, but the variable nature of their paths and sediment supply means that Horn Island has received differing amounts of sediment from these proximal rivers throughout the Holocene. To analyze the stratigraphy and sediment characteristics of Horn Island, we will utilize 24 vibracores (up to 6 meters in length) from offshore Horn Island that were obtained by the United States Geological Survey (USGS) and 9 onshore drill cores (up to 28 meters in length) from the Mississippi Department of Environmental Quality. High-resolution LiDAR data collected by the National Oceanic and Atmospheric Administration in 2010 will be used to describe modern geomorphic barrier environments. We will employ down-core x-ray diffraction and x-ray fluorescence analyses to identify mineralogical and chemical signatures that potentially correspond to unique signatures of the fluvial sources of proximal rivers. New radiocarbon ages will be used to constrain the timing of island formation and alterations in sediment supply. High-resolution shallow geophysical data will provide regional information on paleo-fluvial courses and their influence on island formation, sediment supply, and evolution.

Low-temperature anaerobic digestion of swine manure in a plug-flow reactor.

PubMed

Massé, Daniel I; Gilbert, Yan; Saady, N M C; Liu, Charle

2013-01-01

A low-temperature (25 degrees C) anaerobic eight-compartment (PF01 to PF08) cascade reactor simulating a plug-flow reactor (PFR) treating pig manure was monitored for a year. The bioreactor was fed at an average loading rate of 2.4 +/- 0.2 g of total chemical oxygen demand (TCOD) per litre of reactor per day for a theoretical hydraulic retention time (HRT) of 67 +/- 7 d. An average of 79% of TCOD was removed from pig manure (converted into biogas and in sediments), whereas specific methane yields ranging from 397 to 482 NL CH4 kg(-1) VS (148.6 to 171.4 NL CH4 kg(-1) TCOD) were obtained. After 150 d, fluctuating performances of the process were observed, associated with solids accumulation in the upstream compartments, preventing the complete anaerobic digestion of swine manure in the compartments PF01 to PF04. Low-temperature anaerobic PFR represents an interesting alternative for the treatment of pig manure and recovery of green energy. Further investigations regarding a modified design, with better accumulating solids management, are needed to optimize the performance of this low-temperature PFR treating pig manure.

Formation of siliceous sediments in brandy after diatomite filtration.

PubMed

Gómez, J; Gil, M L A; de la Rosa-Fox, N; Alguacil, M

2015-03-01

Brandy is quite a stable spirit but sometimes light sediment appears. This sediment was separated and analysed by IR and SEM-EDX. It was revealed that the sediment is composed mostly of silica and residual organic matter. Silica was present as an amorphous phase and as microparticles. In an attempt to reproduce the formation of the sediment, a diatomite extract was prepared with an ethanol/water mixture (36% vol.) and a calcined diatomite similar to that used in brandy filtration. This extract was added to unfiltered brandy in different amounts. After 1 month, the Si concentration decreased in all samples and sediments with similar compositions and features to those found in the unstable brandy appeared. The amounts of sediment obtained were directly related to the decrease in Si concentration in solution. Consequently, it can be concluded that siliceous sediment in brandy originates from Si released during diatomite filtration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Field studies of estuarine turbidity under different freshwater flow conditions, Kaipara River, New Zealand

NASA Astrophysics Data System (ADS)

Mitchell, Steven B.; Green, Malcolm O.; MacDonald, Iain T.; Pritchard, Mark

2017-11-01

We present a first interpretation of three days of measurements made in 2013 from the tidal reaches of the Kaipara River (New Zealand) under both low and high freshwater inputs and a neap tidal cycle. During the first day, we occupied two stations that were approximately 6 km apart in a tidal reach that runs for 25 km from the river mouth to the upstream limit of tidal influence. During the second day, longitudinal surveys were conducted over a distance of 6 km centred on the upstream station. The data reveal a turbidity maximum in the form of a high-concentration 'plug' of suspended mud that was advected downstream on the ebbing tide past the upper (HB) measurement station and which exchanged sediment with the seabed by settling at low slack water and by resuspension in the early flooding tide. The data suggest that fine sediment is transported landwards and trapped in the upper part of the tidal reach under these low-flow conditions. On the third day of measurements we repeated the experiments of the first day but later in the year, for a much higher freshwater flow. This interpretation of our data set highlights the potential contribution of a range of processes to the generation of the observed suspended-sediment signals, including resuspension of local bed sediment, advection by the tidal current, settling of suspended sediment over a long timescale compared to the advection timescale, advection of longitudinal gradients in suspended sediment, and suppression of vertical mixing by density stratification of the water column. The level of temporal and spatial detail afforded by these measurements allows a much clearer understanding of the timing and importance of vertical stratification on the transport of suspended particulate matter than is generally possible using fixed-point sensors.

Preparation and clinical evaluation of succinylated collagen punctal plugs in dry eye syndrome: a pilot study.

PubMed

Hadassah, J; Bhuvaneshwari, Namita; Singh, Deepti; Sehgal, P K

2010-01-01

This is a pilot study of 10 eyes of 6 patients. This paper describes the preparation and clinical evaluation of succinylated collagen punctal plugs (SCPP) in the treatment of dry eye syndrome (DES). SCPP were prepared from succinylated collagen with the exact dimensions of the punctum (length 1.5-2.5 mm, diameter 0.2-0.5 mm, water content between 50 and 55%). All the patients were clinically evaluated for best corrected visual acuity (BCVA), tear fluid levels (TFL), protein content, tear fluid osmolarity (TFO), fluorescence staining of the cornea and tear break-up time (TBUT) before and after punctal occlusion with SCPP. TFL improved among all the patients after punctal occlusion with SCPP. BCVA showed improvement in case 4 (right eye/left eye), case 5 (left eye) and case 6 (right eye), who had developed dry eyes due to environmental conditions. Protein content increased on day 7 in all the patients and gradually decreased. TFO decreased on days 3 and 5 in all patients after punctal occlusion with SCPP, and showed the same levels on day 14. TFL, PC, TFO and TBUT showed significant improvement in all the patients after punctal occlusion with SCPP. All patients experienced symptomatic relief after punctal occlusion with SCPP. There was no discomfort, foreign body sensation, plug extrusion, corneal aberration, infection, or formation of pyogenic granuloma with SCPP. SCPP stands as a promising alternative to other punctal plugs in the treatment of DES. Copyright 2010 S. Karger AG, Basel.

The Classification and Geomorphic Implications of Thaw Lakes on the Arctic Coastal Plain, Alaska

DTIC Science & Technology

1975-12-01

Plain is underlain by ice-rich marine sediments , the product of several marine transgressions and regressions. Numerous thaw lake basins of...variable morphology and distribution have developed on the perennially frozen sediments (permafrost) of this low-lying plain. Most notable are the large...mechanism of thaw lake formation was recognized whereby sediment laden ice rafts initiated thawing of the permafrost and formation of lake basins

Records of transient avulsion-related river patterns in ancient deposits: evidence for different styles of channel-floodplain coupling

NASA Astrophysics Data System (ADS)

Hajek, E. A.; Edmonds, D.; Millard, C.; Toms, L.; Fogaren, C.

2012-12-01

River mobility and avulsion are important controls on how course and fine sediment are distributed across alluvial basins. In some systems, broad distributary channel networks that form during channel avulsions contribute significantly to overbank aggradation within the basin and help transport relatively coarse sediment from the channel out onto the floodplain. In contrast, avulsion-related deposits are virtually absent in other systems, which primarily avulse either through incision or with no significant aggradational phase preceding channel relocation; in these systems, overbank sedimentation primarily comprises relatively fine floodplain deposits. In order to constrain the conditions under which distributary-channel networks develop during avulsions, we evaluate channel, avulsion, and floodplain deposits in several ancient units including the Ferris (Maastrichtian/Paleocene, Wyoming), Fort Union (Paleocene, Wyoming), Wasatch (Paleocene/Eocene, Colorado), and Willwood (Paleocene/Eocene, Wyoming) formations. Ancient deposits afford the opportunity to observe multiple (tens to hundreds) channel-avulsion realizations and evaluate characteristic spatial and temporal variability in channel, avulsion, and floodplain deposits within a basin. In each formation, spatial relationships and grain-size distributions of channel, proximal-overbank, distal-overbank, and, where present, avulsion deposits are compared. The thickness, width, and stratigraphic frequency of crevasse-splay and avulsion deposits are characterized in each formation, and paleosol development is documented in order to provide information about relative differences in floodplain conditions (particularly sedimentation rate and floodplain drainage) throughout each unit. We compare these results to modern systems and numerical models. Several formations contain abundant and distinctive evidence of prograding sediment wedges preceding avulsed channels (Willwood Formation and some members of the Wasatch formation), while others contain virtually no avulsion-associated deposits (Ferris Formation). The Fort Union Formation and one member of the Wasatch Formation show a mix of both. These results largely reflect depositional processes and not preservation bias within ancient deposits. Evidence from ancient deposits also suggests sediment partitioning between channels and floodplains was mediated by crevasse-splay production and avulsion, where some systems were "tuned" to produce large splay deposits and other systems produced only infrequent, small splays. Systems that readily produced splay deposits are associated with more prominent avulsion deposits, and splay production seems to be influenced by the particle-size distribution of sediment carried in the channel and floodplain drainage conditions (where abundant fine-sand and coarse-silt sediment and relatively well-drained floodplain conditions promote crevasse-splay production). Avulsion deposits reflect a transient distributary phase associated with a marked increase in local overbank sedimentation rates, but this phase is not ubiquitous to all avulsive systems. The persistence of conditions that promote or inhibit crevasse-splay and avulsion-deposit production may strongly influence channel-floodplain coupling in aggrading fluvial systems.

Selecting Female Mice in Estrus and Checking Plugs.

PubMed

Behringer, Richard; Gertsenstein, Marina; Nagy, Kristina Vintersten; Nagy, Andras

2016-08-01

The female mouse estrous cycle is divided into four phases: proestrus (development of ovarian follicles), estrus (ovulation), metestrus (formation of corpora lutea), and diestrus (beginning of follicle development for next ovulation and elimination of previous oocytes). The appearance of the epithelium of the external genitalia is used to identify the stage of the estrous cycle of a female mouse. This is usually easier to see in strains with either no or only light skin pigmentation. By examining the color, moistness, and degree of swelling of the vagina, females in estrus can readily be identified. To set up the matings, females are examined in the afternoon, and those in estrus are placed into the cages with males (one or two females in each cage with one male). Usually, 50% or more of the selected females will mate. The presence of a vaginal copulation plug next morning indicates that mating has occurred, but it does not mean that a pregnancy will result even if proven breeder fertile males were used. It is important to check vaginal plugs early in the morning because they fall out or are no longer detectable ~12 h after mating or sometimes earlier. © 2016 Cold Spring Harbor Laboratory Press.

Soft sediment deformation structures in the Maastrichtian Ajali Formation Western Flank of Anambra Basin, Southern Nigeria

NASA Astrophysics Data System (ADS)

Olabode, Solomon Ojo

2014-01-01

Soft sediment deformation structures were recognized in the Maastrichtian shallow marine wave to tide influenced regressive sediments of Ajali Formation in the western flank of Anambra basin, southern Nigerian. The soft sediment deformation structures were in association with cross bedded sands, clay and silt and show different morphological types. Two main types recognised are plastic deformations represented by different types of recumbent folds and injection structure represented by clastic dykes. Other structures in association with the plastic deformation structures include distorted convolute lamination, subsidence lobes, pillars, cusps and sand balls. These structures are interpreted to have been formed by liquefaction and fluidization mechanisms. The driving forces inferred include gravitational instabilities and hydraulic processes. Facies analysis, detailed morphologic study of the soft sediment deformation structures and previous tectonic history of the basin indicate that the main trigger agent for deformation is earthquake shock. The soft sediment deformation structures recognised in the western part of Anambra basin provide a continuous record of the tectonic processes that acted on the regressive Ajali Formation during the Maastrichtian.

Microbial acetogenesis as a source of organic acids in ancient Atlantic Coastal Plain sediments

USGS Publications Warehouse

Chapelle, F.H.; Bradley, P.M.

1996-01-01

Field and laboratory evidence shows that deeply buried (90-888 m) fine-grained sediments of the Atlantic Coastal Plain contain viable acetogenic microorganisms, and that these microorganisms actively produce organic acids. Concentrations of formate, acetate, and propionate in pore waters extracted from fine-grained sediments ranged from 50 ??M to 5 mM and were much higher than in adjacent pore waters associated with sandy sediments (<2 ??M). Laboratory studies showed that asceptically cored fine-grained sediments incubated under a H2 atmosphere produced formate and acetate, and that H14CO-3 was converted to 14C-acetate and 14C-formate over time. An enrichment culture of these acetogenic microorganisms was recovered from one long-term incubation that showed the presence of several morphologically distinct gram-positive, rod-shaped bacteria. These microorganisms were capable of growth under autotrophic (H2 + CO2), heterotrophic (syringate), and mixotrophic (H2 + CO2 + syringate) conditions. These results suggest that microbial acetogenesis, rather than abiotic processes, is the most important organic acid-producing mechanism during low-temperature (???30 ??C) diagenesis of Atlantic Coastal Plain sediments.

Geologic columns for the ICDP-USGS Eyreville A and B cores, Chesapeake Bay impact structure: Sediment-clast breccias, 1096 to 444 m depth

USGS Publications Warehouse

Edwards, L.E.; Powars, D.S.; Gohn, G.S.; Dypvik, H.

2009-01-01

The Eyreville A and B cores, recovered from the "moat" of the Chesapeake Bay impact structure, provide a thick section of sediment-clast breccias and minor stratified sediments from 1095.74 to 443.90 m. This paper discusses the components of these breccias, presents a geologic column and descriptive lithologic framework for them, and formalizes the Exmore Formation. From 1095.74 to ??867 m, the cores consist of nonmarine sediment boulders and sand (rare blocks up to 15.3 m intersected diameter). A sharp contact in both cores at ??867 m marks the lowest clayey, silty, glauconitic quartz sand that constitutes the base of the Exmore Formation and its lower diamicton member. Here, material derived from the upper sediment target layers, as well as some impact ejecta, occurs. The block-dominated member of the Exmore Formation, from ??855-618.23 m, consists of nonmarine sediment blocks and boulders (up to 45.5 m) that are juxtaposed complexly. Blocks of oxidized clay are an important component. Above 618.23 m, which is the base of the informal upper diamicton member of the Exmore Formation, the glauconitic matrix is a consistent component in diamicton layers between nonmarine sediment clasts that decrease in size upward in the section. Crystalline-rock clasts are not randomly distributed but rather form local concentrations. The upper part of the Exmore Formation consists of crudely fining-upward sandy packages capped by laminated silt and clay. The overlap interval of Eyreville A and B (940-??760 m) allows recognition of local similarities and differences in the breccias. ?? 2009 The Geological Society of America.

Friction pull plug welding: chamfered heat sink pull plug design

NASA Technical Reports Server (NTRS)

Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

2005-01-01

The average strength of a pull plug weld is increased and weak bonding eliminated by providing a dual included angle at the top one third of the pull plug. Plugs using the included angle of the present invention had consistent high strength, no weak bonds and were substantially defect free. The dual angle of the pull plug body increases the heat and pressure of the weld in the region of the top one third of the plug. This allows the plug to form a tight high quality solid state bond. The dual angle was found to be successful in elimination of defects on both small and large plugs.

Friction pull plug welding: dual chamfered plate hole

NASA Technical Reports Server (NTRS)

Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

2001-01-01

Friction Pull Plug Welding (FPPW) is a solid state repair process for defects up to one inch in length, only requiring single sided tooling (OSL) for usage on flight hardware. Early attempts with FPPW followed the matching plug/plate geometry precedence of the successful Friction Push Plug Welding program, however no defect free welds were achieved due to substantial plug necking and plug rotational stalling. The dual chamfered hole has eliminated plug rotational stalling, both upon initial plug/plate contact and during welding. Also, the necking of the heated plug metal under a tensile heating/forging load has been eliminated through the usage of the dual chamfered plate hole.

Processes of Formation of Spheroidal Concretions and Inferences for "Blueberries" in Meridiani Planum Sediments

NASA Astrophysics Data System (ADS)

Coleman, M. L.

2005-03-01

Formation of spheroidal concretions on Earth results generally from reactions of organic matter in oxidized sediments. Had organic matter been present in Merididani Planum it could have produced a reduced iron mineral phase later oxidized to hematite.

Clearance of a Mucus Plug

NASA Astrophysics Data System (ADS)

Bian, Shiyao; Zheng, Ying; Grotberg, James B.

2008-11-01

Mucus plugging may occur in pulmonary airways in asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. How to clear the mucus plug is essential and of fundamental importance. Mucus is known to have a yield stress and a mucus plug behaves like a solid plug when the applied stresses are below its yield stress τy. When the local stresses reaches τy, the plug starts to move and can be cleared out of the lung. It is then of great importance to examine how the mucus plug deforms and what is the minimum pressure required to initiate its movement. The present study used the finite element method (FEM) to study the stress distribution and deformation of a solid mucus plug under different pressure loads using ANSYS software. The maximum shear stress is found to occur near the rear transition region of the plug, which can lead to local yielding and flow. The critical pressure increases linearly with the plug length and asymptotes when the plug length is larger than the half channel width. Experimentally a mucus simulant is used to study the process of plug deformation and critical pressure difference required for the plug to propagate. Consistently, the fracture is observed to start at the rear transition region where the plug core connects the films. However, the critical pressure is observed to be dependent on not only the plug length but also the interfacial shape.

Sediment Transport on Continental Shelves: Storm Bed Formation and Preservation in Heterogeneous Sediments

DTIC Science & Technology

2012-01-01

occurred during the Cretaceous period. The simulated storm bed for such an extratropical cyclone that lasts 4 days was deposited as deep as 75 m and had...Int. Assoc. Sedimentol. Spec. Publ. (2012) 44, 295-310 Sediment transport on continental shelves: storm bed formation and preservation in...xDept. of Earth Science, Memorial University of Newfoundland, St. Johns, Newfoundland, Canada ABSTRACT Many storm beds are constructed of silt/sand

Stratigraphy and paleoenvironment of Miocene phosphatic rocks in the East San Francisco Bay region, California

USGS Publications Warehouse

Hill, James M.

1979-01-01

A stratigraphic study of the Monterey Group in the East San Francisco Bay Region, California, indicates that a depositional basin began to subside in early to middle Miocene time. The Miocene sea transgressed from the west or southwest, and the area subsided to a possible water depth of 500 to 2,500 m. The Monterey Group within the study area is a time-transgressive sequence of six sandstone and shale formations. Stratigraphic cycles of interbedded sandstone and shale formations are related to the amount of terrigenous sediment input into the basin as well as the depositional environment. During periods of low terrigenous sedimentation, biogenetic sedimentation in the form of diatomite layers were interbedded with hemipelagic muds and thin turbidite sands. These diatom-rich sediments were probably deposited within the upper bathyal zone (180 to 500 m) and, during lithification, diagenetically altered to form siliceous shales and cherts. As terrigenous sedimentation increased, probably due to periodic uplift east of the study area, biogenetic sedimentation was masked until finer grained sediment at a lower rate of deposition reoccurred. As the basin filled and a higher energy environment prevailed; coarse-grained sediment was again deposited until a lower energy environment resumed. Three types of inorganic phosphate are present within the study area: nodular, Pelletal, and pebbles of sandy phosphatic mudstone. The nodular phosphate is associated with the siliceous shale formations and formed within diatomite layers before compaction and lithification. The other two types of phosphate are found within the sandstone formations and probably originated in a shallower, higher energy environment than the siliceous shales. Faulting was active during middle to late Miocene time. The change in stratigraphic thickness across the Mission fault is 350 m which may approximate the vertical (?) displacement along this fault. This displacement took place in middle to upper Miocene time and apparently caused erosion of the upper formations of the Monterey Group on the west side of the Mission fault before the Briones Formation was deposited in late Miocene time. Depositional thinning of the Monterey Group in the southern portion of the study area may imply that the Hayward and Calaveras faults were also active at this time.

[Evidence of lacrimal plugs via high resolution ultrasound].

PubMed

Tost, Frank H W; Darman, Jacques

2003-07-01

The practical value of high-frequency ultrasound (transducer frequency of 20 MHz) for studying lacrimal plugs positioned into canaliculi was proved. Twelve patients with twenty intracanalicular plugs and two punctum plugs were examined via high-frequency B-scan ultrasonography using 20 MHz transducer (model I3 Sacramento, USA). Detection and localisation of the intracanalicular plugs was made by a 20 MHz sector scanner. The ultrasound examinations were performed 1 - 24 month after the placement of lacrimal plugs. After patient's head positioning, the high-frequency ultrasound investigation was done via immersion fluid (2 % methylcellulose). All patients with dry eye treated by lacrimal plug implant showed echographic structure in the lacrimal canaliculus. In transversal echograms it was possible to image both canaliculi together when the lids were half-closed. Contrary to the normal state, it was not necessary to inject viscous fluid into the canaliculus. High-resolution ultrasound was able to differentiate the normal canaliculus from the findings after plug placement. The echograms can vary from one plug type to another. Highly reflective structures were found after the placement of silicone intracanalicular plugs, e. g. HERRICK-Plug. In contrast, the ultrasonic image taken through acrylic polymer intracanalicular plugs showed homogeneous small reflective inner structure, e. g. SMART-Plug. However, smooth and flat acoustic interface between acrylic polymer plug and the lacrimal canaliculus produced strong echoes. 20 MHz ultrasound seems to be well suited for the detection and localisation of intracanalicular plugs. By use of 20 MHz ultrasound scans it is possible to get high-quality images of the intracanalicular plug and around lacrimal canaliculus. Compared with UBM, the depth of penetration is much higher with negligible resolution. On the whole, we believe that 20 MHz ultrasound can become a useful tool for evaluating the placement of intracanalicular plugs after insertion.

A catalog of porosity and permeability from core plugs in siliciclastic rocks

USGS Publications Warehouse

Nelson, Philip H.; Kibler, Joyce E.

2003-01-01

Porosity and permeability measurements on cored samples from siliciclastic formations are presented for 70 data sets, taken from published data and descriptions. Data sets generally represent specific formations, usually from a limited number of wells. Each data set is represented by a written summary, a plot of permeability versus porosity, and a digital file of the data. The summaries include a publication reference, the geologic age of the formation, location, well names, depth range, various geologic descriptions, and core measurement conditions. Attributes such as grain size or depositional environment are identified by symbols on the plots. An index lists the authors and date, geologic age, formation name, sandstone classification, location, basin or structural province, and field name.

Storage stability of light cycle oil: Studies for the root substance of insoluble sediment formation

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

Motohashi, Katsunori; Nakazono, Kingo; Oki, Masami

1995-04-01

The storage stabilities of a raw and pretreated light cycle oils (LCOs) have been studied under the condition of ASTM D2274-88. The raw LCO was pretreated by five methods; 10% sulfuric acid-extraction, 10% sodium hydroxide-extraction, methanol-extraction, active clay- treatment, and catalytic hydrotreating. The raw and pretreated LCOs were aged at 95{degrees}C for 144 hours while oxygen was bubbled. The pretreatment except 10% sulfuric acid-extraction showed the decreasing sediments. After removing the sediments by filtration, the changes of component of the residual oils before and after aging, were analyzed by GUMS, GC/AED and GC/NPD. Remarkable changes were observed in nitrogen compoundsmore » such as anilines and indoles, sulfur compounds such as thiophenols, and oxygen compounds such as phenol and its derivatives. It was clarified that the sediment formation was caused by the mutual interactions among heteroatom-containing compounds mentioned above. In addition, unstable hydrocarbons were suggested to behave as key-compounds for sediment formation.« less

Seismic wave velocity of hydrate-bearing fine-grained sediments sampled from the Ulleung basin in East Sea, Korea

NASA Astrophysics Data System (ADS)

Kim, H.; Kwon, T.; Cho, G.

2012-12-01

Synthesizing gas hydrate in a fine-grained natural seabed sediment sample, mainly composed of silty-to-clayey soils, has been hardly attempted due to the low permeability. It has been known that hydrate loci in pore spaces and heterogeneity of hydrate growth in core-scale play a critical role in determining physical properties of hydrate-bearing sediments. In the presented study, we attempted to identify the effect of hydrate growth morphology on seismic velocities in natural fine-grained sediments sampled from the Ulleung Basin in East Sea. We synthesized CO2 hydrate in clayey silt sediments in an instrumented oedometric cell and measured seismic velocities during hydrate formation and loading processes. Herein, we present the experiment results on P-wave and S-wave velocities of gas hydrate-bearing fine-grained sediments. It is found that the geophysical properties of gas hydrate-bearing sediments are governed by hydrate saturation and effective stress as well as morphological feature of hydrate formation in sediments.

Permeability-porosity data sets for sandstones

USGS Publications Warehouse

Nelson, P.H.

2004-01-01

Due to the variable nature of permeability-porosity relations, core should be obtained and permeability (k) and porosity (??) should be determined on core plugs in the laboratory for the formation of interest. A catalog of k versus (??) data sets is now available on the Web. Examples from the catalog are considered to illustrate some aspects of k versus ?? dependencies in siliciclastic reservoirs.

Flow-sediment-large woody debris interplay: Introducing an appropriately scaled laboratory experiment

NASA Astrophysics Data System (ADS)

Friedrich, H.; Spreitzer, G.; Tunnicliffe, J. F.

2017-12-01

The morphology of steep (>0.01 m/m) forested streams is governed not only by water-sediment interplay, but also by accumulations of coarse and fine organic debris. In this project we look at the jamming dynamics (formation, persistence and hydraulic feedbacks) of large woody debris with the help of scaled laboratory experiments. In New Zealand, the recruitment of wood from both natural tree-fall and forest harvesting has led to obstruction of culverts, bridges and other river constrictions. Understanding the dynamics of jam formation and persistence is important for harvest practice guidelines, management of sediment accumulation, as well as establishing impacts to habitat and infrastructure. In this study, we provide the context of our work, present our experimental setup for studying the complex flow-sediment-wood interactions and present some initial results. In our experimental setup, we varied feed rates of sediment and organic fine material in order to establish concentration thresholds for jam formation, and development of sediment retention capacity upstream of the jam. Large woody debris accumulation is studied for different blocking scenarios, and the effect on sediment transport is measured. Sediment quantities and changes in channel bed morphology upstream of the critical cross section are evaluated, together with resulting backwater effects, and associated energy losses. In the long term, our results will inform our understanding of the processes that take place from the mobilization of woody debris to accumulation.

Detection gas presence in lakes bottom sediments based on seismic investigations.

NASA Astrophysics Data System (ADS)

Krylov, Pavel; Nurgaliev, Danis; Yasonov, Pavel

2017-04-01

Seismic investigations are used for various tasks, such as the study of the bottom sediments properties, finding sunken objects, reconstruction the reservoir history, etc. Detailed seismic investigation has been carried out in the southern part of Lake Bol'shoe Yarovoe (Altai Krai), Lake Sunukul (Chelyabinsk region), Lake Kisegach to map the bottom sediments and features associated with the presence of gas. The obtained results demonstrate that various types of gas can be recognized in lakes sediments, such as pockmarks, acoustic turbidity, gas flares, seeps. These features, on the one hand, prevent the reconstruction of sequence stratigraphic patterns and, on the other hand, contribute to understanding of the processes of gas formation and migration in the sediments, possible impacts of these processes on the formation of sediments enriched in the organic matter. Also, it helps to recognize these processes in the ancient sediments. The paper points out the importance of studying the formation of methane in lake sediments, because it plays an important role in the climate change. The work was carried out according to the Russia Government's Program of Competitive Growth of Kazan Federal University, supported by the grant provided to the Kazan State University for performing the state program in the field of scientific research, and partially supported by the Russian Foundation for Basic research (grant nos. 16-35-00452).

Authigenic molybdenum formation in marine sediments: A link to pore water sulfide in the Santa Barbara Basin

USGS Publications Warehouse

Zheng, Yen; Anderson, Robert F.; VanGeen, A.; Kuwabara, J.

2000-01-01

Pore water and sediment Mo concentrations were measured in a suite of multicores collected at four sites along the northeastern flank of the Santa Barbara Basin to examine the connection between authigenic Mo formation and pore water sulfide concentration. Only at the deepest site (580 m), where pore water sulfide concentrations rise to >0.1 ??M right below the sediment water interface, was there active authigenic Mo formation. At shallower sites (550,430, and 340 m), where pore water sulfide concentrations were consistently <0.05 ??M, Mo precipitation was not occuring at the time of sampling. A sulfide concentration of ???0.1 ??M appears to be a threshold for the onset of Mo-Fe-S co-precipitation. A second threshold sulfide concentration of ???100 ??M is required for Mo precipitation without Fe, possibly as Mo-S or as particle-bound Mo. Mass budgets for Mo were constructed by combining pore water and sediment results for Mo with analyses of sediment trap material from Santa Barbara Basin as well as sediment accumulation rates derived from 210Pb. The calculations show that most of the authigenic Mo in the sediment at the deepest site is supplied by diffusion from overlying bottom waters. There is, however, a non-lithogenic particulate Mo associated with sinking particles that contributes ???15% to the total authigenic Mo accumulation. Analysis of sediment trap samples and supernant brine solutions indicates the presence of non-lithogenic particulate Mo, a large fraction of which is easily remobilized and, perhaps, associated with Mn-oxides. Our observations show that even with the very high flux of organic carbon reaching the sediment of Santa Barbara Basin, active formation of sedimentary authigenic Mo requires a bottom water oxygen concentration below 3 ??M. However, small but measurable rates of authigenic Mo accumulation were observed at sites where bottom water oxygen ranged between 5 and 23 ??M, indicating that the formation of authigenic Mo occured in the recent past, but not at the time of sampling. Copyright ?? 2000 Elsevier Science Ltd.

Prediction Of The Fracture Due To Mannesmann Effect In Tube Piercing

NASA Astrophysics Data System (ADS)

Fanini, S.; Ghiotti, A.; Bruschi, S.

2007-05-01

Mannesmann piercing process is a well-known hot rolling process used for seamless tube production. Its special feature is the so-called Mannesmann effect, that is the cavity formation in the center of the cylindrical billet and its propagation along the axis due to stress state caused by the rolls in the early stages of the process. The cavity is then expanded and sized in its internal diameter by an incoming plug. The industrial requirement is to know quite precisely the characteristics of the cavity especially in terms of its location along the billet axis in order to minimize the plug wear and the oxidation of the pierced bar. However, the scientific knowledge about the fracture mechanism leading to the Mannesmann effect is still limited, even if several theories have been proposed; this lack makes the design and optimization of the process through numerical simulations still a challenging task. The aim of this work is then to develop a suitably calibrated FE model of the piercing process in its first stage before the plug arrival, in order to investigate the Mannesmann effect using different damage criteria. Hot tensile tests, capable to reproduce the industrial conditions in terms of temperature, strain rate, and stress states, are carried out to investigate the material workability and to determine the parameters of the damage models on specimens machined from continuous-casting steel billets. The calculated parameters are implemented in the numerical model of the process and a sensitivity analysis to the different criteria is carried out, comparing numerical results with non-plug piercing tests conducted in the industrial plant.

Sedimentary architecture and depositional environment of Kudat Formation, Sabah, Malaysia

NASA Astrophysics Data System (ADS)

Ghaheri, Samira; Suhaili, Mohd; Sapari, Nasiman; Momeni, Mohammadsadegh

2017-12-01

Kudat Formation originated from deep marine environment. Three lithofacies association of deep marine turbidity channel was discovered in three Members of the Kudat Formation in Kudat Peninsula, Sabah, Malaysia. Turbidite and deep marine architecture elements was described based on detailed sedimentological studies. Four architecture elements were identified based on each facies association and their lithology properties and character: inner external levee that was formed by turbidity flows spill out from their confinement of channel belt; Lobes sheet that was formed during downslope debris flows associated with levee; Channel fill which sediments deposited from high to low density currents with different value of sediment concentration; and overbank terrace which was formed by rapid suspension sedimentation. The depositional environment of Kudat Formation is shelf to deep marine fan.

Patterns of surface burrow plugging in a colony of black-tailed prairie dogs occupied by black-footed ferrets

USGS Publications Warehouse

Eads, David E.; Biggins, Dean E.

2012-01-01

Black-tailed prairie dogs (Cynomys ludovicianus) can surface-plug openings to a burrow occupied by a black-footed ferret (Mustela nigripes). At a coarse scale, surface plugs are more common in colonies of prairie dogs occupied by ferrets than in colonies without ferrets. However, little is known about spatial and temporal patterns of surface plugging in a colony occupied by ferrets. In a 452-ha colony of black-tailed prairie dogs in South Dakota, we sampled burrow openings for surface plugs and related those data to locations of ferrets observed during spotlight surveys. Of 67,574 burrow openings in the colony between June and September 2007, 3.7% were plugged. In a colony-wide grid of 80 m × 80 m cells, the occurrence of surface plugging (≥1 opening plugged) was greater in cells used by ferrets (93.3% of cells) than in cells not observably used by ferrets (70.6%). Rates of surface plugging (percentages of openings plugged) were significantly higher in cells used by ferrets (median = 3.7%) than in cells without known ferret use (median = 3.2%). Also, numbers of ferret locations in cells correlated positively with numbers of mapped surface plugs in the cells. To investigate surface plugging at finer temporal and spatial scales, we compared rates of surface plugging in 20-m-radius circle-plots centered on ferret locations and in random plots 1–4 days after observing a ferret (Jun–Oct 2007 and 2008). Rates of surface plugging were greater in ferret-plots (median = 12.0%) than in random plots (median = 0%). For prairie dogs and their associates, the implications of surface plugging could be numerous. For instance, ferrets must dig to exit or enter plugged burrows (suggesting energetic costs), and surface plugs might influence microclimates in burrows and consequently influence species that cannot excavate soil (e.g., fleas that transmit the plague bacterium Yersinia pestis).

Vivianite formation and distribution in Lake Baikal sediments

NASA Astrophysics Data System (ADS)

Fagel, N.; Alleman, L. Y.; Granina, L.; Hatert, F.; Thamo-Bozso, E.; Cloots, R.; André, L.

2005-04-01

In an effort to better understand vivianite formation processes, four Lake Baikal sediment cores spanning two to four interglacial stages in the northern, central and southern basins and under various biogeochemical environments are scrutinized. The vivianite-rich layers were detected by anomalous P-enrichments in bulk geochemistry and visually by observations on X-radiographs. The millimetric concretions of vivianite were isolated by sieving and analysed by X-ray diffraction, scanning electron microscope (SEM), microprobe, infrared spectroscopy, inductively coupled plasma atomic emission spectrometry and mass spectrometry (ICP-AES, ICP-MS). All the vivianites display similar morphological, mineralogical and geochemical signature, suggesting a common diagenetic origin. Their geochemical signature is sensitive to secondary alteration where vivianite concretions are gradually transformed from the rim to the center into an amorphous santabarbaraite phase with a decreasing Mn content. We analysed the spatial and temporal distribution of the concretions in order to determine the primary parameters controlling the vivianite formation, e.g., lithology, sedimentation rates, and porewater chemistry. We conclude that vivianite formation in Lake Baikal is mainly controlled by porewater chemistry and sedimentation rates, and it is not a proxy for lacustrine paleoproductivity. Vivianite accumulation is not restricted to areas of slow sedimentation rates (e.g., Academician and Continent ridges). At the site of relatively fast sedimentation rate, i.e., the Posolsky Bank near the Selenga Delta, vivianite production may be more or less related to the Selenga River inputs. It could be also indirectly related to the past intensive methane escapes from the sediments. While reflecting an early diagenetic signal, the source of P and Fe porewater for vivianites genesis is still unclear.

Bacterial ethane formation from reduced, ethylated sulfur compounds in anoxic sediments

USGS Publications Warehouse

Oremland, R.S.; Whiticar, Michael J.; Strohmaier, F.E.; Kiene, R.P.

1988-01-01

Trace levels of ethane were produced biologically in anoxic sediment slurries from five chemically different aquatic environments. Gases from these locations displayed biogenic characteristics, having 12C-enriched values of ??13CH4 (-62 to -86%.), ??13C2H6 (-35 to -55%.) and high ratios (720 to 140,000) of CH4 [C2H6 + C3H8]. Endogenous production of ethane by slurries was inhibited by autoclaving or by addition of the inhibitor of methanogenic bacteria, 2-bromoethanesulfonic acid (BES). Ethane formation was stimulated markedly by ethanethiol (ESH), and, to a lesser extent, by diethylsulfide (DES). Formation of methane and ethane in ESH- or DES-amended slurries was blocked by BES. Experiments showed that ethionine (or an analogous compound) could be a precursor of ESH. Ethylamine or ethanol additions to slurries caused only a minor stimulation of ethane formation. Similarly, propanethiol additions resulted in only a minor enhancement of propane formation. Cell suspensions of a methyltrophic methanogen produced traces of ethane when incubated in the presence of DES, although the organism did not grow on this compound. These results indicate that methanogenic bacteria produce ethane from the traces of ethylated sulfur compounds present in recent sediments. Preliminary estimates of stable carbon isotope fractionation associated with sediment methane formation from dimethylsulfide was about 40%., while ethane formation from DES and ESH was only 4. 6 and 6.5%., respectively. ?? 1988.

Aeroacoustics of supersonic jet flows from contoured and solid/porous conical plug-nozzles

NASA Technical Reports Server (NTRS)

Dosanjh, Darshan S.; Das, Indu S.

1987-01-01

The results of an experimental study of the acoustic far-field, the shock associated noise, and the nature of the repetitive shock structure of supersonic jet flows issuing from plug-nozzles having externally-expanded plugs with pointed termination operated at a range of supercritical pressure ratios Xi approaching 2 to 4.5 are reported. The plug of one of these plug-nozzles was contoured. The other plug-nozzles had short conical plugs with either a solid surface or a combination of solid/porous surface of different porosities. The contoured and the uncontoured plug-nozzles had the same throat area and the same annulus-radius ratio K = R sub p/R sub N = 0.43. As the result of modifications of the shock structure, the acoustic performance of improperly expanded jet flows of an externally-expanded short uncontoured plug of an appropriate geometry with suitably perforated plug and a pointed termination, is shown to approach the acoustic performance of a shock-free supersonic jet issuing from an equivalent externally-expanded contoured plug-nozzle.

Geologic columns for the ICDP-USGS Eyreville A and C cores, Chesapeake Bay impact structure: Postimpact sediments, 444 to 0 m depth

USGS Publications Warehouse

Edwards, L.E.; Powars, D.S.; Browning, J.V.; McLaughlin, P.P.; Miller, K.G.; ,; Kulpecz, A.A.; Elbra, T.

2009-01-01

A 443.9-m-thick, virtually undisturbed section of postimpact deposits in the Chesapeake Bay impact structure was recovered in the Eyreville A and C cores, Northampton County, Virginia, within the "moat" of the structure's central crater. Recovered sediments are mainly fine-grained marine siliciclastics, with the exception of Pleistocene sand, clay, and gravel. The lowest postimpact unit is the upper Eocene Chickahominy Formation (443.9-350.1 m). At 93.8 m, this is the maximum thickness yet recovered for deposits that represent the return to "normal marine" sedimentation. The Drummonds Corner beds (informal) and the Old Church Formation are thin Oligocene units present between 350.1 and 344.7 m. Above the Oligocene, there is a more typical Virginia coastal plain succession. The Calvert Formation (344.7-225.4 m) includes a thin lower Miocene part overlain by a much thicker middle Miocene part. From 225.4 to 206.0 m, sediments of the middle Miocene Choptank Formation, rarely reported in the Virginia coastal plain, are present. The thick upper Miocene St. Marys and Eastover Formations (206.0-57.8 m) appear to represent a more complete succession than in the type localities. Correlation with the nearby Kiptopeke core indicates that two Pliocene units are present: Yorktown (57.8-32.2 m) and Chowan River Formations (32.2-18.3 m). Sediments at the top of the section represent an upper Pleistocene channel-fill and are assigned to the Butlers Bluff and Occohannock Members of the Nassawadox Formation (18.3-0.6 m). ?? 2009 The Geological Society of America.

Friction pull plug welding: top hat plug design

NASA Technical Reports Server (NTRS)

Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

2001-01-01

Friction Pull Plug Welding is a solid state repair process for defects up to one inch in length, only requiring single sided tooling, or outside skin line (OSL), for preferred usage on flight hardware. The most prevalent defect associated with Friction Pull Plug Welding (FPPW) was a top side or inside skin line (ISL) lack of bonding. Bonding was not achieved at this location due to the reduction in both frictional heat and welding pressure between the plug and plate at the end of the weld. Thus, in order to eliminate the weld defects and increase the plug strength at the plug `top` a small `hat` section is added to the pull plug for added frictional heating and pressure.

Friction pull plug welding: top hat plug design

NASA Technical Reports Server (NTRS)

Coletta, Edmond R. (Inventor); Cantrell, Mark A. (Inventor)

2002-01-01

Friction Pull Plug Welding is a solid state repair process for defects up to one inch in length, only requiring single sided tooling, or outside skin line (OSL), for preferred usage on flight hardware. The most prevalent defect associated with Friction Pull Plug Welding (FPPW) was a top side or inside skin line (ISL) lack of bonding. Bonding was not achieved at this location due to the reduction in both frictional heat and welding pressure between the plug and plate at the end of the weld. Thus, in order to eliminate the weld defects and increase the plug strength at the plug `top` a small `hat` section is added to the pull plug for added frictional heating and pressure.

Processes of Formation of Spheroidal Concretions and Inferences for "Blueberries" in Meridiani Planum Sediments

NASA Technical Reports Server (NTRS)

Coleman, Max

2005-01-01

The MER Opportunity Athena Science team has described spheroidal hematite nodules in sediments at Meridiani Planum on Mars [1]. They were informally referred to as "Blueberries" in the initial press releases and for brevity that is the name to be used in this abstract. Not all spheroidal objects in sediments are nodular concretions, but this paper will discuss the diagenetic processes possibly relevant to understanding the origin of the Blueberries. There are many occurrences of spheroidal diagenetic concretions in terrestrial sediments and detailed work has been done to understand the processes of their formation. In particular, it is possible to reconstruct the controls on their shapes and compositions, both mineral and chemical. Although there may not be good analogs for the Meridiani Planum hematite spherules on Earth, it may be possible to deduce the former environmental conditions that led to their formation and whether they might retain (or even be) biosignatures.

Physical properties of hydrate‐bearing sediments

USGS Publications Warehouse

Waite, William F.; Santamarina, J.C.; Cortes, D.D.; Dugan, Brandon; Espinoza, D.N.; Germaine, J.; Jang, J.; Jung, J.W.; Kneafsey, T.J.; Shin, H.; Soga, K.; Winters, William J.; Yun, T.S.

2009-01-01

Methane gas hydrates, crystalline inclusion compounds formed from methane and water, are found in marine continental margin and permafrost sediments worldwide. This article reviews the current understanding of phenomena involved in gas hydrate formation and the physical properties of hydrate‐bearing sediments. Formation phenomena include pore‐scale habit, solubility, spatial variability, and host sediment aggregate properties. Physical properties include thermal properties, permeability, electrical conductivity and permittivity, small‐strain elastic P and S wave velocities, shear strength, and volume changes resulting from hydrate dissociation. The magnitudes and interdependencies of these properties are critically important for predicting and quantifying macroscale responses of hydrate‐bearing sediments to changes in mechanical, thermal, or chemical boundary conditions. These predictions are vital for mitigating borehole, local, and regional slope stability hazards; optimizing recovery techniques for extracting methane from hydrate‐bearing sediments or sequestering carbon dioxide in gas hydrate; and evaluating the role of gas hydrate in the global carbon cycle.

Aspergillus fumigatus colonization of punctal plugs.

PubMed

Tabbara, Khalid F

2007-01-01

Punctal plugs are used in patients with dry eye syndrome to preserve the tears. In this report, I present two cases of Aspergillus fumigatus colonization of punctal plugs. Observational series of two cases. Approval was obtained from the institutional review board. Two men aged 29 and 31 years developed black spots inside the hole of punctal plug, which looked like eyeliner deposits. The deposits inside the hole of the plug in each patient were removed and cultured. Cultures of the two punctal plugs black deposits grew A fumigatus. Bacterial cultures were negative. Colonization of the punctal plug hole with A fumigatus was observed in two cases. It is recommended that punctal plugs be removed in patients undergoing refractive or intraocular procedures or in patients who are receiving topical corticosteroids. Current punctal plugs should be redesigned to avoid the presence of an inserter hole.

A sample-freezing drive shoe for a wire line piston core sampler

USGS Publications Warehouse

Murphy, F.; Herkelrath, W.N.

1996-01-01

Loss of fluids and samples during retrieval of cores of saturated, noncohesive sediments results in incorrect measures of fluid distributions and an inaccurate measure of the stratigraphic position of the sample. To reduce these errors, we developed a hollow drive shoe that freezes in place the lowest 3 inches (75 mm) of a 1.88-inch-diameter (48 mm), 5-foot-long (1.5 m) sediment sample taken using a commercial wire line piston core sampler. The end of the core is frozen by piping liquid carbon dioxide at ambient temperature through a steel tube from a bottle at the land surface to the drive shoe where it evaporates and expands, cooling the interior surface of the shoe to about -109??F (-78??C). Freezing a core end takes about 10 minutes. The device was used to collect samples for a study of oil-water-air distributions, and for studies of water chemistry and microbial activity in unconsolidated sediments at the site of an oil spill near Bemidji, Minnesota. Before freezing was employed, samples of sandy sediments from near the water table sometimes flowed out of the core barrel as the sampler was withdrawn. Freezing the bottom of the core allowed for the retention of all material that entered the core barrel and lessened the redistribution of fluids within the core. The device is useful in the unsaturated and shallow saturated zones, but does not freeze cores well at depths greater than about 20 feet (6 m) below water, possibly because the feed tube plugs with dry ice with increased exhaust back-pressure, or because sediment enters the annulus between the core barrel and the core barrel liner and blocks the exhaust.

A novel sterane, 27-nor-24-methyl-5α-cholestane, in sediments

NASA Astrophysics Data System (ADS)

Schouten, Stefan; Sinninghe Damsté, Jaap S.; Schoell, Martin; de Leeuw, Jan W.

1994-09-01

A novel sterane, 27-nor-24-methyl-5α-cholestane, has been identified in sedimentary hydrocarbon mixtures by coinjection with an authentic standard. The C27 sterane occurs in silica-rich sediments from the Monterey Formation, USA, the Onnagawa Formation, Japan, and the Menilite Shale, Poland, and in bituminous marls from the Vena del Gesso basin, Italy. The compound seems to be biosynthetically related to 24-norcholestanes which co-occurs in sometimes relatively high amounts. The 13C-content of the sterane in the Monterey Formation indicates an algal source similar to other steranes present in this sediment. A diatom or a dinoflagellate source is suggested for this compound.

New Technology Sparks Smoother Engines and Cleaner Air

NASA Technical Reports Server (NTRS)

2001-01-01

Automotive Resources, Inc. (ARI) has developed a new device for igniting fuel in engines-the SmartPlug.TM SmartPlug is a self-contained ignition system that may be retrofitted to existing spark-ignition and compression-ignition engines. The SmartPlug needs as little as six watts of power for warm-up, and requires no electricity at all when the engine is running. Unlike traditional spark plugs, once the SmartPlug ignites the engine, and the engine heats up, the power supply for the plug is no longer necessary. In the utility industry, SmartPlugs can be used in tractors, portable generators, compressors, and pumps. In addition to general-purpose applications, such as lawn mowers and chainsaws, SmartPlugs can also be used in the recreational, marine, aviation, and automotive industries. Unlike traditional ignition systems, the SmartPlug system requires no distributor, coil points, or moving parts. SmartPlugs are non-fouling, with a faster and cleaner burn than traditional spark plugs. They prevent detonation and are not sensitive to moisture, allowing them to be used on a variety of engines. Other advantages include no electrical noise, no high voltage, exceptionally high altitude capabilities, and better cold-start statistics than those of standard spark ignition systems. Future applications for the SmartPlug are being evaluated by manufacturers in the snowmobile industry.

Calcium-Citrate-Phosphate Solution Injection for In Situ Strontium-90 Immobilization

NASA Astrophysics Data System (ADS)

Fruchter, J. S.; Vermeul, V.; Szecsody, J.; Williams, M. D.; Fritz, B. G.

2010-12-01

Sr-90 present in groundwater and the vadose zone at the Hanford 100N area due to past waste disposal practices has reached the nearby Columbia River, as evidenced by Sr-90 concentrations in near river wells and aquifer tubes and near shore sediments. Sr-90 is currently being remediated by adsorption onto apatite (55 times stronger than Sr-90 adsorption to sediment), followed by incorporation of the Sr-90 into the apatite structure. If the Sr-90 can remain immobilized for 300 years (~ten 29.1-yr half-lives of Sr-90 decay), it will have decayed below regulatory limits to Y-90 and to stable Zr-90. Apatite [Ca10(PO4)6(OH)2] is being precipitated in situ by injection of an aqueous solution of Ca-citrate and Na-phosphate through a series of injection wells spaced 30 ft on center, forming a 300-ft-long permeable reactive barrier. Design criteria for the injection operations were based on 1) amendment volume and mass injected, 2) amendment arrival at adjacent wells, 3) water-level elevation during treatment, and 4) injection rate limitations associated with well plugging. An evaluation of compliance with these injection design criteria was used to assess operational performance and identify candidate wells for supplemental treatment. Injection design criteria were not fully met at 8 of the 16 injection well locations, with the primary deficiency at 4 of 8 locations being the limited vertical extent of Hanford formation treatment due to low-river-stage conditions during the injection. Wells whose extent of treatment did not meet design criteria were recommended for retreatment. Although injection design criteria were not fully met at a significant number of well locations, aqueous performance assessment monitoring data collected to date indicate good barrier performance. Aqueous Sr-90 monitoring in four compliance monitoring wells over a year following the high concentration injections indicates 84% to 95% decrease in Sr-90 concentrations (relative to the low and high end of the baseline range, respectively). In addition, post treatment sediment cores were collected to quantify the amount of apatite that was formed from the barrier-emplacement operations. Results indicate that the processes that account for the observed reduction in aqueous Sr-90 concentrations include: a) incorporation of Sr-90 into apatite (about 39.4% of the total Sr-90 mass in the core), b) ion exchange flushing due to the Ca-citrate-PO4 solution injection (about 47% of the mass), and c) a small increase in Sr-90 adsorbed to sediment and apatite precipitate.

Design parameters for rotating cylindrical filtration

NASA Technical Reports Server (NTRS)

Schwille, John A.; Mitra, Deepanjan; Lueptow, Richard M.

2002-01-01

Rotating cylindrical filtration displays significantly reduced plugging of filter pores and build-up of a cake layer, but the number and range of parameters that can be adjusted complicates the design of these devices. Twelve individual parameters were investigated experimentally by measuring the build-up of particles on the rotating cylindrical filter after a fixed time of operation. The build-up of particles on the filter depends on the rotational speed, the radial filtrate flow, the particle size and the gap width. Other parameters, such as suspension concentration and total flow rate are less important. Of the four mechanisms present in rotating filters to reduce pore plugging and cake build-up, axial shear, rotational shear, centrifugal sedimentation and vortical motion, the evidence suggests rotational shear is the dominant mechanism, although the other mechanisms still play minor roles. The ratio of the shear force acting parallel to the filter surface on a particle to the Stokes drag acting normal to the filter surface on the particle due to the difference between particle motion and filtrate flow can be used as a non-dimensional parameter that predicts the degree of particle build-up on the filter surface for a wide variety of filtration conditions. c2002 Elsevier Science B.V. All rights reserved.

Tectonics and crustal structure of the Saurashtra peninsula: based on Gravity and Magnetic data

NASA Astrophysics Data System (ADS)

Mishra, A. K.; Singh, A.; Singh, U. K.

2016-12-01

The Saurashtra peninsula is located at the North Western margin of the Indian shield which occurs as a horst block between the rifts namely as Kachchh, Cambay and Narmada. It is important because of occurrence of moderate earthquake and presence of mesozoic sediments below the Deccan trap. The maps of bouguer gravity anomaly and the total intensity magnetic anomalies of Saurashtra have delineated six circular gravity highs of magnitudes 40-60 mGal and 800-1000 nT respectively. In order to understand the location, structure and depth of the source body, methods like continuous wavelet transform (CWT), Euler deconvolution and power spectrum analysis have been implemented in the potential field data. The CWT and Euler deconvolution give 16-18 km average depth of volcanic plug in Junagadh and Rajula region. From the power spectrum analysis, it is found that average Moho depth in the Saurashtra is about 36-38 km. Keeping the constraints obtained from geophysical studies like borehole, deep seismic survey, receiver function analysis and geological information, combined gravity and magnetic modeling have been performed. Detailed crustal structure of the Saurashtra region has been delineated along two profiles which pass from prominent geological features Junagadh and Rajula volcanic plugs respectively.

Formation of fine sediment deposit from a flash flood river in the Mediterranean Sea

USGS Publications Warehouse

Grifoll, Manel; Gracia, Vicenç; Aretxabaleta, Alfredo L.; Guillén, Jorge; Espino, Manuel; Warner, John C.

2014-01-01

We identify the mechanisms controlling fine deposits on the inner-shelf in front of the Besòs River, in the northwestern Mediterranean Sea. This river is characterized by a flash flood regime discharging large amounts of water (more than 20 times the mean water discharge) and sediment in very short periods lasting from hours to few days. Numerical model output was compared with bottom sediment observations and used to characterize the multiple spatial and temporal scales involved in offshore sediment deposit formation. A high-resolution (50 m grid size) coupled hydrodynamic-wave-sediment transport model was applied to the initial stages of the sediment dispersal after a storm-related flood event. After the flood, sediment accumulation was predominantly confined to an area near the coastline as a result of preferential deposition during the final stage of the storm. Subsequent reworking occurred due to wave-induced bottom shear stress that resuspended fine materials, with seaward flow exporting them toward the midshelf. Wave characteristics, sediment availability, and shelf circulation determined the transport after the reworking and the final sediment deposition location. One year simulations of the regional area revealed a prevalent southwestward average flow with increased intensity downstream. The circulation pattern was consistent with the observed fine deposit depocenter being shifted southward from the river mouth. At the southern edge, bathymetry controlled the fine deposition by inducing near-bottom flow convergence enhancing bottom shear stress. According to the short-term and long-term analyses, a seasonal pattern in the fine deposit formation is expected.

Phenolic compounds participating in mulberry juice sediment formation during storage.

PubMed

Zou, Bo; Xu, Yu-Juan; Wu, Ji-Jun; Yu, Yuan-Shan; Xiao, Geng-Sheng

The stability of clarified juice is of great importance in the beverage industry and to consumers. Phenolic compounds are considered to be one of the main factors responsible for sediment formation. The aim of this study is to investigate the changes in the phenolic content in clarified mulberry juice during storage. Hence, separation, identification, quantification, and analysis of the changes in the contents of phenolic compounds, both free and bound forms, in the supernatant and sediments of mulberry juice, were carried out using high performance liquid chromatographic system, equipped with a photo-diode array detector (HPLC-PDA) and HPLC coupled with quadrupole-time of flight mass spectrometric (HPLC-QTOF-MS/MS) techniques. There was an increase in the amount of sediment formed over the period of study. Total phenolic content of supernatant, as well as free phenolic content in the extracts of the precipitate decreased, whereas the bound phenolic content in the sediment increased. Quantitative estimation of individual phenolic compounds indicated high degradation of free anthocyanins in the supernatant and sediment from 938.60 to 2.30 mg/L and 235.60 to 1.74 mg/g, respectively. A decrease in flavonoids in the supernatant was also observed, whereas the contents of bound forms of gallic acid, protocatechuic acid, caffeic acid, and rutin in the sediment increased. Anthocyanins were the most abundant form of phenolics in the sediment, and accounted for 67.2% of total phenolics after 8 weeks of storage. These results revealed that phenolic compounds, particularly anthocyanins, were involved in the formation of sediments in mulberry juice during storage.

Thermo-sensitive polymer nanospheres as a smart plugging agent for shale gas drilling operations.

PubMed

Wang, Wei-Ji; Qiu, Zheng-Song; Zhong, Han-Yi; Huang, Wei-An; Dai, Wen-Hao

2017-01-01

Emulsifier-free poly(methyl methacrylate-styrene) [P(MMA-St)] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcohol-water medium by a solvothermal method. Then, through radical graft copolymerization of thermo-sensitive monomer N -isopropylacrylamide (NIPAm) and hydrophilic monomer acrylic acid (AA) onto the surface of P(MMA-St) nanospheres at 80 °C, a series of thermo-sensitive polymer nanospheres, named SD-SEAL with different lower critical solution temperatures (LCST), were prepared by adjusting the mole ratio of NIPAm to AA. The products were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, particle size distribution, and specific surface area analysis. The temperature-sensitive behavior was studied by light transmittance tests, while the sealing performance was investigated by pressure transmission tests with Lungmachi Formation shales. The experimental results showed that the synthesized nanoparticles are sensitive to temperature and had apparent LCST values which increased with an increase in hydrophilic monomer AA. When the temperature was higher than its LCST value, SD-SEAL played a dual role of physical plugging and chemical inhibition, slowed down pressure transmission, and reduced shale permeability remarkably. The plugged layer of shale was changed to being hydrophobic, which greatly improved the shale stability.

Formulation Development of High Strength Gel System and Evaluation on Profile Control Performance for High Salinity and Low Permeability Fractured Reservoir

PubMed Central

Zhang, Chengli; Qu, Guodong

2017-01-01

For the large pores and cracks of reservoirs with low temperatures, high salinity, and low permeability, a new type of high strength gel ABP system is developed in this paper. The defects of conventional gels such as weak gel strength, no gelling, and easy dehydration are overcome under the conditions of low temperature and high salinity. The temperature and salt resistance, plugging characteristics, and EOR of the gel system are studied. Under the condition of 32°C and 29500 mg/L salinity, the ABP system formulation is for 0.3% crosslinking agent A + 0.09% coagulant B + 3500 mg/L polymer solution P. The results show that when the temperature was increased, the delayed crosslinking time of the system was shortened and the gel strength was increased. The good plugging characteristics of the ABP system were reached, and the plugging rate was greater than 99% in cores with different permeability. A good profile control performance was achieved, and the recovery rate was improved by 19.27% on the basis of water flooding. In the practical application of the gel system, the salinity of formation water and the permeability of fractures are necessary to determine the appropriate formulation. PMID:28592971

Diatom-sedimentation feedback generates a self-organized geomorphic landscape on intertidal mudflats (Invited)

NASA Astrophysics Data System (ADS)

van de Koppel, J.; Weerman, E.; Herman, P.

2010-12-01

During spring, intertidal flats can exhibit strikingly regular spatial patterns of diatom-covered hummocks alternating with almost bare, water-filled hollows. We hypothesize that 1) the formation of this geomorphic landscape is caused by a strong interaction between benthic diatoms and sediment dynamics, inducing spatial self-organization, and 2) that self-organization affects ecosystem functioning by increasing the net average sedimentation on the tidal flat. We present a combined empirical and mathematical study to test the first hypothesis. We determined how the sediment erosion threshold varied with diatom cover and elevation. Our results were incorporated into a mathematical model to investigate whether the proposed mechanism could explain the formation of the observed patterns. Our mathematical model confirmed that the interaction between sedimentation, diatom growth and water redistribution could induce the formation of regular patterns on the intertidal mudflat. The model predicts that areas exhibiting spatially-self-organized patterns have increased sediment accretion and diatom biomass compared with areas lacking spatial patterns. We tested this prediction by following the sediment elevation during the season on both patterned and unpatterned parts of the mudflat. The results of our study confirmed our model prediction, as more sediment was found to accumulate in patterned parts of the mudflat, revealing how self-organization affected the functioning of mudflat ecosystems. Our study on intertidal mudflats provides a simple but clear-cut example of how the interaction between biological and geomorphological processes, through the process of self-organization, induces a self-organized geomorphic landscape.

Allogenic and autogenic controls on sedimentation in the central Sumatra basin as an analogue for Pennsylvanian coal-bearing strata in the Appalachian basin

USGS Publications Warehouse

Cecil, C. Blaine; Dulong, Frank T.; Cobb, James C.

1993-01-01

Recent sedimentation patterns in the central Sumatra basin, Republic of Indonesia, may help to explain the cyclic stratigraphy of the Pennsylvanian System of the eastern United States. Modern influx of fluvial siliciclastic sediment to the epeiric seas of the Sunda shelf, including the Strait of Malacca, appears to be highly restricted by rain forest cover within the ever-wet climate belt of equatorial Sumatra. As a result, much of the marine and estuarine environments appear to be erosional or nondepositional except for localized deposition of sediment in slack water areas, such as the down-stream end of islands. Contemporaneously, thick (>13 m), laterally extensive (>70,000 km2), peat deposits are forming on poorly drained coastal lowlands. Modern peat formation in this study, therefore, is not coeval with aggrading fluvial siliciclastic systems, a situation that commonly is assumed in many depositional models of coal formation. The stratigraphy of Pleistocene and Holocene sediments on the Sunda shelf, as well as those of the Pennsylvanian System, appears to be better explained by the allocyclic controls of climate and sea-level change on sediment flux rather than by depositional models that are based on autocyclic processes. The objective of this paper is to evaluate allocyclic and autocyclic controls on sedimentation in an epeiric setting in a humid (ever-wet) tropical region. Of particular interest are the factors that control peat formation and siliciclastic sediment flux in rivers, estuaries, and open marine environments.

Investigations of young (< 2.94 Ma) Hadar Formation deposits and their implication for basin development in southern Afar, Ethiopia

NASA Astrophysics Data System (ADS)

DiMaggio, E.; Arrowsmith, R.; Campisano, C. J.; Johnson, R. A.; Deino, A. L.; Warren, M.; Fisseha, S.; Cohen, A. S.

2014-12-01

Sedimentary deposits in Pliocene extensional rift basins in the Afar Depression, Ethiopia chronicle the evolution and paleoenvironmental context of early humans. In the lower Awash Valley, the long-studied Hadar Basin still lacks constraints on basin development during the onset and termination of Hadar Formation (~3.8 - 2.94 Ma) sedimentation. Here we present new mapping and analysis of tephra deposits from a 26 meter-thick section of sediments exposed in the central Ledi-Geraru project area at Gulfaytu, including 20 m of sediments and tephras conformably overlying a 2.94 Ma tephra marker bed (BKT-2U) that previously served as the uppermost dated tephra of the Hadar Formation. Within the overlying 20 meters of primarily lacustrine strata, we identified eight post-BKT-2U tuffs; four were suitable for geochemical characterization, and one yielded an 40Ar/39Ar age of 2.931 ± 0.034 Ma. Based on regional sedimentation rates and the tephra 40Ar/39Ar age, we infer that the newly mapped Hadar Formation at Gulfaytu represents ca. 20 kyr of post-BKT-2 sedimentation. An erosional surface marked by a conglomerate truncates the strata at Gulfaytu, and shows similarities to the well-documented Busidima unconformity surface to the southwest, suggesting that structural changes after 2.93 Ma also affected basin conditions in central Ledi-Geraru. Furthermore, subsurface geophysical investigations support a model whereby deposition rates and the stratigraphic thickness of paleo-Lake Hadar sediments are greatest in the central Ledi-Geraru, ~20 km northeast of the well-exposed lacustrine-dominated sediments of the Hadar Formation. In addition to preserving a record of post-BKT-2 strata, the central Ledi Geraru hosts the thickest subsurface lacustrine sedimentary record within the Hadar Basin hitherto described, making central Ledi-Geraru an ideal location for collecting a continuous core by the Hominin Sites and Paleolakes Drilling Project (HSPDP).

HYFLUX: Satellite Exploration of Natural Hydrocarbon Seeps and Discovery of a Methane Hydrate Mound at GC600

NASA Astrophysics Data System (ADS)

Garcia-Pineda, O. G.; MacDonald, I. R.; Shedd, W.; Zimmer, B.

2009-12-01

Analysis of natural hydrocarbon seeps is important to improve our understanding of methane flux from deeper sediments to the water column. In order to quantify natural hydrocarbon seep formations in the Northern Gulf of Mexico, a set of 686 Synthetic Aperture Radar (SAR) images was analyzed using the Texture Classifying Neural Network Algorithm (TCNNA), which processes SAR data to delineate oil slicks. This analysis resulted in a characterization of 396 natural seep sites distributed in the northern GOM. Within these sites, a maximum of 1248 individual vents where identified. Oil reaching the sea-surface is deflected from its source during transit through the water column. This presentation describes a method for estimating locations of active oil vents based on repeated slick detection in SAR. One of the most active seep formations was detected in MMS lease block GC600. A total of 82 SAR scenes (collected by RADARSAT-1 from 1995 to 2007) was processed covering this region. Using TCNNA the area covered by each slick was computed and Oil Slicks Origins (OSO) were selected as single points within detected oil slicks. At this site, oil slick signatures had lengths up to 74 km and up to 27 km^2 of area. Using SAR and TCNNA, four active vents were identified in this seep formation. The geostatistical mean centroid among all detections indicated a location along a ridge-line at ~1200m. Sea truth observations with an ROV, confirmed that the estimated location of vents had a maximum offset of ~30 m from their actual locations on the seafloor. At the largest vent, a 3-m high, 12-m long mound of oil-saturated gas hydrate was observed. The outcrop contained thousands of ice worms and numerous semi-rigid chimneys from where oily bubbles were escaping in a continuous stream. Three additional vents were found along the ridge; these had lower apparent flow, but were also plugged with gas hydrate mounds. These results support use of SAR data for precise delineation of active seep formation and shallow gas hydrate deposits.

Method of measuring material properties of rock in the wall of a borehole

DOEpatents

Overmier, David K.

1985-01-01

To measure the modulus of elasticity of the rock in the wall of a borehole, a plug is cut in the borehole wall. The plug, its base attached to the surrounding rock, acts as a short column in response to applied forces. A loading piston is applied to the top of the plug and compression of the plug is measured as load is increased. Measurement of piston load and plug longitudinal deformation are made to determine the elastic modulus of the plug material. Poisson's ratio can be determined by simultaneous measurements of longitudinal and lateral deformation of the plug in response to loading. To determine shear modulus, the top of the plug is twisted while measurements are taken of torsional deformation.

Method of measuring material properties of rock in the wall of a borehole

DOEpatents

Overmier, D.K.

1984-01-01

To measure the modulus of elasticity of the rock in the wall of a borehole, a plug is cut in the borehole wall. The plug, its base attached to the surrounding rock, acts as a short column in response to applied forces. A loading piston is applied to the top of the plug and compression of the plug is measured as load is increased. Measurements of piston load and plug longitudinal deformation are made to determine the elastic modulus of the plug material. Poisson's ratio can be determined by simultaneous measurements of longitudinal and lateral deformation of the plug in response to loading. To determine shear modulus, the top of the plug is twisted while measurements are taken of torsional deformation.

Final report: Initial ecosystem response of salt marshes to ditch plugging and pool creation: Experiments at Rachel Carson National Wildlife Refuge (Maine)

USGS Publications Warehouse

Adamowicz, S.C.; Roman, C.T.

2002-01-01

This study evaluates the response of three salt marshes, associated with the Rachel Carson National Wildlife Refuge (Maine), to the practice of ditch plugging. Drainage ditches, originally dug to drain the marsh for mosquito control or to facilitate salt hay farming, are plugged with marsh peat in an effort to impound water upstream of the plug, raise water table levels in the marsh, and increase surface water habitat. At two study sites, Moody Marsh and Granite Point Road Marsh, ditch plugs were installed in spring 2000. Monitoring of hydrology, vegetation, nekton and bird utilization, and marsh development processes was conducted in 1999, before ditch plugging, and then in 2000 and 2001 (all parameters except nekton), after ditch plugging. Each study site had a control marsh that was monitored simultaneously with the plugged marsh, and thus, we employed a BACI study design (before, after, control, impact). A third site, Marshall Point Road Marsh, was plugged in 1998. Monitoring of the plugged and control sites was conducted in 1999 and 2000, with limited monitoring in 2001, thus there was no ?before? plug monitoring. With ditch plugging, water table levels increased toward the marsh surface and the areal extent of standing water increased. Responding to a wetter substrate, a vegetation change from high marsh species (e.g., Spartina patens) to those more tolerant of flooded conditions (e.g., Spartina alterniflora) was noted at two of the three ditch plugged sites. Initial response of the nekton community (fishes and decapod crustaceans) was evaluated by monitoring utilization of salt marsh pools using a 1m2 enclosure trap. In general, nekton species richness, density, and community structure remained unchanged following ditch plugging at the Moody and Granite Point sites. At Marshall Point, species richness and density (number of individuals per m2) were significantly greater in the experimental plugged marsh than the control marsh (<2% of the control marsh was open water habitat vs. 11% of the plugged marsh). The response of birds, categorized as waterfowl & waterbirds, shorebirds & wading birds, gulls & terns, and miscellaneous (raptors, passerines, other), was variable. Following ditch plugging, bird species richness increased at the Granite Point site (1999 pre-plug = 15.4, 2000 post-plug = 26.2, 2001 post-plug = 38.7). Because of a low sample size at Moody Marsh, reliable statements on species richness cannot be made. Density of birds (no. of birds per ha) remained unchanged with ditch plugging at Granite Point Marsh, although there was a strong, but not statistically significant, trend toward increased density. This study only reports on initial responses of marsh functions to ditch plugging. Monitoring should continue at these sites, and perhaps at additional sites, for the next decade or so. A monitoring plan is recommended. Long-term monitoring will include evaluation of salt marsh development processes using SET (surface elevation table) methodology. There is concern, although not confirmed, that as ditch-plugged marshes become wetter and marsh grass production declines their ability to keep pace with sea level rise could be jeopardized. It is suggested that ditch plugging should be considered an experimental marsh management technique. Additional monitoring on the physical and habitat responses of ditch-plugged marshes is required, along with assessments of other techniques aimed at restoring open water habitat to the marsh surface.

Development and production integration of a planarized AlCu interconnect process for submicron CMOS

NASA Astrophysics Data System (ADS)

Brown, Kevin C.; Hill, Rodney; Reddy, Krishna; Gadepally, Kamesh

1995-09-01

A planarized aluminum alloy interconnect has been developed as an alternative to tungsten plugs for a 0.65 (mu) CMOS technology. Contact resistance can increase with either an inadequate RF sputter clean or titanium that is too thin to reduce the native oxide. Diffusion barrier results show that a minimum amount of titanium nitride, whether deposited conventionally or with collimation, is necessary for low junction leakage and good sort yield. Stacked contacts and vias are supported while via resistance and defect density are improved. Electrical bridging due to silicon residues from AlSiCu can be minimized with metal overetching, but not to the extent of AlCu. Sidewall pitting was observed to be due to galvanic corrosion from copper precipitate formation. Overall yield has been improved along with decreased wafer cost compared to conventional tungsten plug technology.

Self-Structuring of Granular material under Capillary Bulldozing

NASA Astrophysics Data System (ADS)

Dumazer, Guillaume; Sandnes, Bjørnar; Ayaz, Monem; Måløy, Knut Jørgen; Flekkøy, Eirik

2017-06-01

An experimental observation of the structuring of a granular suspension under the progress of a gas/liquid meniscus in a narrow tube is reported here. The granular material is moved and compactifies as a growing accumulation front. The frictional interaction with the confining walls increases until the pore capillary entry pressure is reached. The gas then penetrates the clogged granular packing and a further accumulation front is formed at the far side of the plug. This cyclic process continues until the gas/liquid interface reaches the tube's outlet, leaving a trail of plugs in the tube. Such 1D pattern formation belongs to a larger family of patterning dynamics observed in 2D Hele-Shaw geometry. The cylindrical geometry considered here provides an ideal case for a theoretical modelling for forced granular matter oscillating between a long frictional phase and a sudden viscous fluidization.

Provenance Analysis of Upper Cretaceous - Paleogene Sandstones in the Foreland Basin System of the Tansen Unit, Central Nepal

NASA Astrophysics Data System (ADS)

Neupane, B.; Ju, Y.; Allen, C.

2016-12-01

The continental deposits foreland basin of Central Nepal, Amile Formation, Bhainskati Formation and Dumri Formation (Tansen unit) are the key region for provenance analysis, preserved almost complete sedimentation history of tectonic collision of Indian and Asian plates. Samples from two field traverses are examined petrographically and through zircon U-Pb dating, one traverse through the Tansen Group, and another through its potential source rocks, the Higher and Tethys Himalaya. The Tansen Group ages are well known through fossil assemblages. We examine sandstone-bearing units of the Tansen Group, the upper 3 of 5 Formations. The optical petrography data and resulting classify Tansen sediments as "recycled orogenic" and "Quartzose recycled", indicating that Indian cratonal sediments as the likely source of sediments for the Amile Formations, and the Tethyan Himalaya as the source for the Bhainskati Formation, and both the Tethys and Higher Himalaya as the major sources for the Dumri Formation. The Cretaceous to Paleocene pre-collisional Amile Formation is dominated by a broad 1830 Ma age peak with neither Paleozoic nor Neoproterozic zircons, but hosts a significant proportion (23%) of syndepositional Cretaceous zircons (121 to 105 Ma) indicative of nearby Cretaceous volcanism at that time. Therefore, the rare volcanic fragments in detritus of Amile Formation were derived from the Rajmahal Volcanic Province defining the middle to late Cretaceous depositional age. The other Formations of the Tansen Group are more similar to Tethys units than to Higher Himalaya. Further, the 23+/-1 Ma zircons in two of the crystalline Higher Himalaya units suggest that they could not have been exposed until at or after this time.

The Connection Between Sediment Supply and Paired Strath Terrace Formation at Arroyo Seco, CA, USA.

NASA Astrophysics Data System (ADS)

Finnegan, N. J.

2015-12-01

Although wide, longitudinally traceable, paired strath terraces in river canyons are frequently argued to reflect periods of higher sediment supply, there is no consensus on how changes in sediment supply translate into dramatic changes in valley morphology. Here, quantitative analysis of LiDAR data is combined with field observations in Arroyo Seco, in the Santa Lucia Range of Central California, to develop a conceptual model for paired bedrock terrace formation and its connection to sediment supply. The most recently formed bedrock terrace in Arroyo Seco grades onto a prominent alluvial fan surface, suggesting that planation of straths in Arroyo Seco occurs as downstream alluvial fans aggrade. This aggradation apparently buffers Arroyo Seco's bedrock channel from base level fall on the Reliz Canyon Fault, which separates the bedrock and alluvial sections of the river. Notably, despite the fact that bedrock terraces grade smoothly onto alluvial fan surfaces, the deep aggradation of sediment downstream is not seen upstream in bedrock channel sections. Gravel on straths is typically only 0.5-1 m thick. Instead, excess gravel appears to be accommodated by the lateral planation of the wide strath itself. LiDAR evidence suggests that strath planation is associated with braiding, which is often triggered by increases in sediment supply. Given the high lateral mobility of braided streams and the extremely fractured (and hence easily detached) mudstone valley walls along Arroyo Seco, braiding provides a simple connection between sediment supply and lateral planation in Arroyo Seco. In Arroyo Seco, fan incision (under decreased sediment supply) should exhume a bedrock step whose height represents the accumulated fault slip during fan aggradation. The upstream propagation of this exhumed step as a knickpoint provides a simple mechanism to connect drops in sediment supply to rapid vertical incision, valley narrowing and strath terrace formation. Long profile data for Arroyo Seco shows clear evidence that the last two generations of strath terraces terminate upstream at knickpoints. OSL dating (Taylor and Sweetkind, 2014) constrains the formation of the two most recent strath terraces to the last ~ 35 kyr, implying at least two reductions in sediment supply relative to capacity during this interval.

Corneal sensitivity, ocular surface health and tear film stability after punctal plug therapy of aqueous deficient dry eye

PubMed Central

Said, Azza Mohamed Ahmed; Farag, Mona Elsayed; Abdulla, Tarek Mohamed; Ziko, Othman Ali Othman; Osman, Wesam Mohamed

2016-01-01

AIM To evaluate the effect of punctal occlusion using thermosensitive (smart plug) versus silicone plug for management of aqueous deficient dry eye on corneal sensitivity, ocular surface health and tear film stability. METHODS A comparative prospective interventional case study included 45 patients with bilateral severe form of aqueous deficient dry eye. In each patient, the smart plug was inserted in the lower punctum of the right eye which was considered as study group 1 and silicone plug was inserted in the lower punctum of the left eye of the same patient which was considered as study group 2. All patients were subjected to careful history taking and questionnaire for subjective assessment of severity of symptoms. Corneal sensitivity, corneal fluorescein, rose bengal staining, Schirmer's I test, tear film break up time and conjunctival impression cytology were performed pre and 1, 3 and 6mo post plug insertion. RESULTS A statistically significant improvement in subjective and objective manifestations occurred following treatment with both types of plugs (P<0.01). The thermosensitive plug caused significant overall improvement, decrease in frequency of application of tear substitutes and improvement of conjunctival impression cytology parameters in the inserted side (P<0.01). Canaliculitis was reported in two eyes (4.4%) following punctal occlusion using thermosensitive plug (study group 1). Spontaneous plug loss occurred in 21 eyes (46.6%) in the silicone plug group (study group 2). CONCLUSION Improvement of subjective and objective manifestations of aqueous deficient dry eye occurs following punctal plug occlusion. Thermosensitive plug has good patient's compliance with fewer complications and lower rates of loss compared to the silicone plug. PMID:27990362

Experimental study of moving throat plug in a shock tunnel

NASA Astrophysics Data System (ADS)

Lee, J. K.; Park, C.; Kwon, O. J.

2015-07-01

An experimental study has been carried out to investigate the flow in the KAIST shock tunnel with two moving throat plugs at a primary shock velocity of 1.19 km/s. The nozzle reservoir pressure and the Pitot pressure at the exit of the nozzle were measured to examine the influence of the moving throat plugs on the shock tunnel flow. To assess the present experimental results, comparisons with previous work using a stationary throat plug were made. The mechanism for closing the moving throat plug was developed and verified. The source of the force to move the plug was the pressure generated when the primary shock was reflected at the bottom of the plug. It was observed that the two plugs terminated the shock tunnel flow after the steady flow. .The time for the plugs to terminate the flow showed good agreement with the calculation of the proposed simple analytic solution. There was a negligible difference in flow values such as the reflected pressure and the Pitot pressure between the moving and the stationary plugs.

Comparative performance of fixed-film biological filters: Application of reactor theory

USGS Publications Warehouse

Watten, B.J.; Sibrell, P.L.

2006-01-01

Nitrification is classified as a two-step consecutive reaction where R1 represents the rate of formation of the intermediate product NO2-N and R2 represents the rate of formation of the final product NO3-N. The relative rates of R1 and R2 are influenced by reactor type characterized hydraulically as plug-flow, plug-flow with dispersion and mixed-flow. We develop substrate conversion models for fixed-film biofilters operating in the first-order kinetic regime based on application of chemical reactor theory. Reactor type, inlet conditions and the biofilm kinetic constants Ki (h-1) are used to predict changes in NH4-N, NO2-N, NO3-N and BOD5. The inhibiting effects of the latter on R1 and R2 were established based on the ?? relation, e.g.:{A formula is presented}where BOD5,max is the concentration that causes nitrification to cease and N is a variable relating Ki to increasing BOD5. Conversion models were incorporated in spreadsheet programs that provided steady-state concentrations of nitrogen and BOD5 at several points in a recirculating aquaculture system operating with input values for fish feed rate, reactor volume, microscreen performance, make-up and recirculating flow rates. When rate constants are standardized, spreadsheet use demonstrates plug-flow reactors provide higher rates of R1 and R2 than mixed-flow reactors thereby reducing volume requirements for target concentrations of NH4-N and NO2-N. The benefit provided by the plug-flow reactor varies with hydraulic residence time t as well as the effective vessel dispersion number, D/??L. Both reactor types are capable of providing net increases in NO2-N during treatment but the rate of decrease in the mixed-flow case falls well behind that predicted for plug-flow operation. We show the potential for a positive net change in NO2-N increases with decreases in the dimensionless ratios K2, (R2 )/K1,( R1 ) and [NO2-N]/[NH4-N] and when the product K1, (R1) t provides low to moderate NH4-N conversions. Maintaining high levels of the latter reduces the effective reactor utilization rate (%) defined here as (RNavg/RNmax)100 where RNavg is the mean reactive nitrogen concentration ([NH4-N] + [NO2-N]) within the reactor, and RNmax represents the feed concentration of the same. Low utilization rates provide a hedge against unexpected increases in substrate loading and reduce water pumping requirements but force use of elevated reactor volumes. Further ?? effects on R1 and R2 can be reduced through use of a tanks-in-series versus a single mixed-flow reactor configuration and by improving the solids removal efficiency of microscreen treatment.

Methymercury Formation in Marine and Freshwater Systems: Sediment Characteristics, Microbial Activity and SRB Phylogeny Control Formation Rates and Food-Chain Exposure

NASA Astrophysics Data System (ADS)

King, J. K.; Saunders, F. M.

2004-05-01

Mercury research in freshwater and marine systems suggests that sediment characteristics such as organic substrate, mercury speciation, and sulfate/sulfide concentrations influence availability of inorganic mercury for methylation. Similarly, sediment characteristics also influence sulfate-reducing bacterial (SRB) respiration as well as the presence/distribution of phylogenetic groups responsible for mercury methylation. Our work illustrates that the process of methylmercury formation in freshwater and marine systems are not dissimilar. Rather, the same geochemical parameters and SRB phylogenetic groups determine the propensity for methylmercury formation and are applicable in both fresh- and marine-water systems. The presentation will include our integration of sediment geochemical and microbial parameters affecting mercury methylation in specific freshwater and marine systems. Constructed wetlands planted with Schoenoplectus californicus and amended with gypsum (CaSO4) have demonstrated a capacity to remove inorganic mercury from industrial outfalls. However, bioaccumulation studies of periphyton, eastern mosquitofish (Gambusia holbrooki) and lake chubsucker (Erimyzon sucetta) were conducted in order to ascertain the availability of wetland-generated methylmercury to biota. Total mercury concentrations in mosquitofish from non-sulfate treated controls and the reference location were significantly lower than those from the low and high sulfate treatments while mean total mercury concentrations in lake chubsuckers were also significantly elevated in the high sulfate treatment compared to the low sulfate, control and reference populations. Methylmercury concentrations in periphyton also corresponded with mercury levels found in the tissue of the lake chubsuckers, and these findings fit well given the trophic levels identified for both species of fish. Overall, data from this study suggest that the initial use of gypsum to accelerate the maturity of a constructed wetland may not prove beneficial with respect to the ultimate objective of mercury sequestration. Current regulations place strict requirements on dredge material placed in confined disposal facilities (CDF) as well as associated effluent waters. Although regulatory guidelines typically address total mercury concentrations, historical data specific to bioaccumulation of mercury suggest that methylmercury concentrations found in sediments and water require attention. Resource agencies are now interested in knowing the likelihood of methylmercury formation in dredge spoil since birds and fish are frequently found feeding in CDFs and the associated mixing zones. Mechanisms that influence methylmercury formation in sediments dictate that dredging of mercury-containing sediments will result in an increased availability of inorganic mercury for methylation. Prior to dredging, the undisturbed sediment contains inorganic mercury complexed to sulfide in an insoluble, unavailable form. However, hydraulic or clamshell dredging can result in an oxidation of sediments and remobilization of mercury-sulfide species thus increasing its availability for methylation. Once sediments are disposed in a CDF, sulfate-reducing bacteria profiles are re-established vertically in dredge spoil and methylmercury synthesis can readily occur.

Combination gas producing and waste-water disposal well

DOEpatents

Malinchak, Raymond M.

1984-01-01

The present invention is directed to a waste-water disposal system for use in a gas recovery well penetrating a subterranean water-containing and methane gas-bearing coal formation. A cased bore hole penetrates the coal formation and extends downwardly therefrom into a further earth formation which has sufficient permeability to absorb the waste water entering the borehole from the coal formation. Pump means are disposed in the casing below the coal formation for pumping the water through a main conduit towards the water-absorbing earth formation. A barrier or water plug is disposed about the main conduit to prevent water flow through the casing except for through the main conduit. Bypass conduits disposed above the barrier communicate with the main conduit to provide an unpumped flow of water to the water-absorbing earth formation. One-way valves are in the main conduit and in the bypass conduits to provide flow of water therethrough only in the direction towards the water-absorbing earth formation.

Combination gas-producing and waste-water disposal well. [DOE patent application

DOEpatents

Malinchak, R.M.

1981-09-03

The present invention is directed to a waste-water disposal system for use in a gas recovery well penetrating a subterranean water-containing and methane gas-bearing coal formation. A cased bore hole penetrates the coal formation and extends downwardly therefrom into a further earth formation which has sufficient permeability to absorb the waste water entering the borehole from the coal formation. Pump means are disposed in the casing below the coal formation for pumping the water through a main conduit towards the water-absorbing earth formation. A barrier or water plug is disposed about the main conduit to prevent water flow through the casing except for through the main conduit. Bypass conduits disposed above the barrier communicate with the main conduit to provide an unpumped flow of water to the water-absorbing earth formation. One-way valves are in the main conduit and in the bypass conduits to provide flow of water therethrough only in the direction towards the water-absorbing earth formation.

Depositional environments and paleocurrent directions in the Precambrian Moeda Formation, Minas Gerais, Brazil

USGS Publications Warehouse

Lindsey, David A.

1975-01-01

The middle Precambrian Moeda Formation of Minas Gerais, Brazil, contains uranium and other minerals believed to be of detrital origin. Two areas of anomalously high concentrations of uranium have been discovered in conglomeratic zones that are interpreted as paleochannels. Because the distribution of uranium is believed to be controlled at least in part by sedimentation, a reconnaissance study was undertaken to assess the depositional environment and sediment dispersal pattern of the Moeda Formation.

Vascular plugs - A key companion to Interventionists - 'Just Plug it'.

PubMed

Ramakrishnan, Sivasubramanian

2015-01-01

Vascular plugs are ideally suited to close extra-cardiac, high flowing vascular communications. The family of vascular plugs has expanded. Vascular plugs in general have a lower profile and the newer variants can be delivered even through a diagnostic catheter. These features make them versatile and easy to use. The Amplatzer vascular plugs are also used for closing intracardiac defects including coronary arterio-venous fistula and paravalvular leakage in an off-label fashion. In this review, the features of currently available vascular plugs are reviewed along with tips and tricks of using them in the cardiac catheterization laboratory. Copyright © 2015. Published by Elsevier B.V.

Black-footed ferrets and recreational shooting influence the attributes of black-tailed prairie dog burrows

USGS Publications Warehouse

Biggins, Dean E.; Ramakrishnan, Shantini; Goldberg, Amanda R.; Eads, David A.

2012-01-01

Black-tailed prairie dogs (Cynomys ludovicianus) plug burrows occupied by black-footed ferrets (Mustela nigripes), and they also plug burrows to entomb dead prairie dogs. We further evaluated these phenomena by sampling connectivity and plugging of burrow openings on prairie dog colonies occupied by ferrets, colonies where recreational shooting was allowed, and colonies with neither shooting nor ferrets. We counted burrow openings on line surveys and within plots, classified surface plugging, and used an air blower to examine subsurface connectivity. Colonies with ferrets had lower densities of openings, fewer connected openings (suggesting increased subsurface plugging), and more surface plugs compared to colonies with no known ferrets. Colonies with recreational shooting had the lowest densities of burrow openings, and line-survey data suggested colonies with shooting had intermediate rates of surface plugging. The extent of surface and subsurface plugging could have consequences for the prairie dog community by changing air circulation and escape routes of burrow systems and by altering energetic relationships. Burrow plugging might reduce prairie dogs' risk of predation by ferrets while increasing risk of predation by American badgers (Taxidea taxus); however, the complexity of the trade-off is increased if plugging increases the risk of predation on ferrets by badgers. Prairie dogs expend more energy plugging and digging when ferrets or shooting are present, and ferrets increase their energy expenditures when they dig to remove those plugs. Microclimatic differences in plugged burrow systems may play a role in flea ecology and persistence of the flea-borne bacterium that causes plague (Yersinia pestis).

Friction Pull Plug and Material Configuration for Anti-Chatter Friction Pull Plug Weld

NASA Technical Reports Server (NTRS)

Littell, Justin Anderson (Inventor)

2016-01-01

A friction pull plug is provided for use in forming a plug weld in a hole in a material. The friction pull plug includes a shank and a series of three frustoconical sections. The relative sizes of the sections assure that a central one of the sections defines the initial contact point between the hole's sides. The angle defined by the central one of the sections reduces or eliminates chatter as the plug is pulled into the hole.

Odyne Plug-In Hybrid Electric Utility Truck Testing | Transportation

Science.gov Websites

Research | NREL Odyne Plug-In Hybrid Electric Utility Truck Evaluation Odyne Plug-In Hybrid data on plug-in hybrid electric utility trucks operated by a variety of companies. Photo courtesy of Odyne, NREL NREL is evaluating the in-service performance of about 120 plug-in hybrid electric utility

SEDIMENT DATA - COMMENCEMENT BAY HYLEBOS WATERWAY - TACOMA, WA - PRE-REMEDIAL DESIGN PROGRAM

EPA Science Inventory

Event 1A/1B Data Files URL address: http://www.epa.gov/r10earth/datalib/superfund/hybos1ab.htm. Sediment Chemistry Data (Database Format): HYBOS1AB.EXE is a self-extracting file which expands to the single-value per record .DBF format database file HYBOS1AB.DBF. This file contai...

Mechanical and electromagnetic properties of northern Gulf of Mexico sediments with and without THF hydrates

USGS Publications Warehouse

Lee, J.Y.; Santamarina, J.C.; Ruppel, C.

2008-01-01

Using an oedometer cell instrumented to measure the evolution of electromagnetic properties, small strain stiffness, and temperature, we conducted consolidation tests on sediments recovered during drilling in the northern Gulf of Mexico at the Atwater Valley and Keathley Canyon sites as part of the 2005 Chevron Joint Industry Project on Methane Hydrates. The tested specimens include both unremolded specimens (as recovered from the original core liner) and remolded sediments both without gas hydrate and with pore fluid exchanged to attain 100% synthetic (tetrahydrofuran) hydrate saturation at any stage of loading. Test results demonstrate the extent to which the electromagnetic and mechanical properties of hydrate-bearing marine sediments are governed by the vertical effective stress, stress history, porosity, hydrate saturation, fabric, ionic concentration of the pore fluid, and temperature. We also show how permittivity and electrical conductivity data can be used to estimate the evolution of hydrate volume fraction during formation. The gradual evolution of geophysical properties during hydrate formation probably reflects the slow increase in ionic concentration in the pore fluid due to ion exclusion in closed systems and the gradual decrease in average pore size in which the hydrate forms. During hydrate formation, the increase in S-wave velocity is delayed with respect to the decrease in permittivity, consistent with hydrate formation on mineral surfaces and subsequent crystal growth toward the pore space. No significant decementation/debonding occurred in 100% THF hydrate-saturated sediments during unloading, hence the probability of sampling hydrate-bearing sediments without disturbing the original sediment fabric is greatest for samples in which the gas hydrate is primarily responsible for maintaining the sediment fabric and for which the time between core retrieval and restoration of in situ effective stress in the laboratory is minimized. In evaluating the impact of core retrieval on specimen properties, it is also important to consider how far removed hydrate-bearing samples are from hydrate stability conditions. ?? 2008 Elsevier Ltd.

Geology of the surficial aquifer system, Broward County, Florida; lithologic logs

USGS Publications Warehouse

Causaras, C.R.

1985-01-01

The geologic framework of the surficial aquifer system, of which the Biscayne aquifer is the major component in Broward County, Florida, is presented in eight geologic cross sections. The cross sections are based on detailed lithologic logs of 27 test wells that were drilled, in the summer of 1981, through the sediments overlying the relatively impermeable units of the Hawthorn Formation, of Miocene age. The cross sections show the aquifer system as a wedge-shaped sequence of Cenozoic sediments. The aquifer thickness gradually decreases from more than 400 feet along the coast to about 160 feet in the west and southwest parts of Broward County. The sediments that comprise the aquifer system range in age from Pliocene to Pleistocene and are assigned to the following stratigraphic units from bottom to top: Tamiami Formation, Caloosahatchee Marl, Fort Thompson Formation, Key Largo Limestone, Anastasia Formation, Miami Oolite, and Pamlico Sand. (USGS)

User's manual for SEDCALC, a computer program for computation of suspended-sediment discharge

USGS Publications Warehouse

Koltun, G.F.; Gray, John R.; McElhone, T.J.

1994-01-01

Sediment-Record Calculations (SEDCALC), a menu-driven set of interactive computer programs, was developed to facilitate computation of suspended-sediment records. The programs comprising SEDCALC were developed independently in several District offices of the U.S. Geological Survey (USGS) to minimize the intensive labor associated with various aspects of sediment-record computations. SEDCALC operates on suspended-sediment-concentration data stored in American Standard Code for Information Interchange (ASCII) files in a predefined card-image format. Program options within SEDCALC can be used to assist in creating and editing the card-image files, as well as to reformat card-image files to and from formats used by the USGS Water-Quality System. SEDCALC provides options for creating card-image files containing time series of equal-interval suspended-sediment concentrations from 1. digitized suspended-sediment-concentration traces, 2. linear interpolation between log-transformed instantaneous suspended-sediment-concentration data stored at unequal time intervals, and 3. nonlinear interpolation between log-transformed instantaneous suspended-sediment-concentration data stored at unequal time intervals. Suspended-sediment discharge can be computed from the streamflow and suspended-sediment-concentration data or by application of transport relations derived by regressing log-transformed instantaneous streamflows on log-transformed instantaneous suspended-sediment concentrations or discharges. The computed suspended-sediment discharge data are stored in card-image files that can be either directly imported to the USGS Automated Data Processing System or used to generate plots by means of other SEDCALC options.

Eddy Current Minimizing Flow Plug for Use in Flow Conditioning and Flow Metering

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

2015-01-01

An eddy-current-minimizing flow plug has open flow channels formed between the plug's inlet and outlet. Each open flow channel includes (i) a first portion that originates at the inlet face and converges to a location within the plug that is downstream of the inlet, and (ii) a second portion that originates within the plug and diverges to the outlet. The diverging second portion is approximately twice the length of the converging first portion. The plug is devoid of planar surface regions at its inlet and outlet, and in fluid flow planes of the plug that are perpendicular to the given direction of a fluid flowing therethrough.

Protection Against Hearing Loss in General Aviation Operations, Phase II

NASA Technical Reports Server (NTRS)

Parker, J. F., Jr.

1972-01-01

An inflight evaluation of four aural protectors is presented. The hearing protection devices studied were ear muffs, plastic ear plugs, rubber ear plugs, and wax ear plugs. It is concluded that ear plugs are satisfactory for providing adequate sound attenuation in general aviation aircraft. However, two problems were found in the use of ear plugs; comfort and interference with cabin communications.

Rotating arc spark plug

DOEpatents

Whealton, John H.; Tsai, Chin-Chi

2003-05-27

A spark plug device includes a structure for modification of an arc, the modification including arc rotation. The spark plug can be used in a combustion engine to reduce emissions and/or improve fuel economy. A method for operating a spark plug and a combustion engine having the spark plug device includes the step of modifying an arc, the modifying including rotating the arc.

Comparison of Experimental Data and Computations Fluid Dynamics Analysis for a Three Dimensional Linear Plug Nozzle

NASA Technical Reports Server (NTRS)

Ruf, J. H.; Hagemann, G.; Immich, H.

2003-01-01

A three dimensional linear plug nozzle of area ratio 12.79 was designed by EADS Space Transportation (former Astrium Space Infrastructure). The nozzle was tested within the German National Technology Program 'LION' in a cold air wind tunnel by TU Dresden. The experimental hardware and test conditions are described. Experimental data was obtained for the nozzle without plug side wall fences at a nozzle pressure ratio of 116 and then with plug side wall fences at NPR 110. Schlieren images were recorded and axial profiles of plug wall static pressures were measured at several spanwise locations and on the plug base. Detailed CFD analysis was performed for these nozzle configurations at NPR 116 by NASA MSFC. The CFD exhibits good agreement with the experimental data. A detailed comparison of the CFD results and the experimental plug wall pressure data are given. Comparisons are made for both the without and with plug side wall fence configurations. Numerical results for density gradient are compared to experimental Schlieren images. Experimental nozzle thrust efficiencies are calculated based on the CFD results. The CFD results are used to illustrate the plug nozzle fluid dynamics. The effect of the plug side wall is emphasized.

Initial Study of Friction Pull Plug Welding

NASA Technical Reports Server (NTRS)

Rich, Brian S.

1999-01-01

Pull plug friction welding is a new process being developed to conveniently eliminate defects from welded plate tank structures. The general idea is to drill a hole of precise, optimized dimensions and weld a plug into it, filling the hole perfectly. A conically-shaped plug is rotated at high angular velocity as it is brought into contact with the plate material in the hole. As the plug is pulled into the hole, friction rapidly raises the temperature to the point at which the plate material flows plastically. After a brief heating phase, the plug rotation is terminated. The plug is then pulled upon with a forging force, solidly welding the plug into the hole in the plate. Three aspects of this process were addressed in this study. The transient temperature distribution was analyzed based on slightly idealized boundary conditions for different plug geometries. Variations in hole geometry and ram speed were considered, and a program was created to calculate volumes of displaced material and empty space, as well as many other relevant dimensions. The relation between the axially applied forging force and the actual forging pressure between the plate and plug surfaces was determined for various configurations.

Eogenetic siderite as an indicator for fluctuations in sedimentation rate in the Oligocene Boom Clay Formation (Belgium)

NASA Astrophysics Data System (ADS)

Laenen, B.; De Craen, M.

2004-01-01

Horizons with septarian concretions are a salient feature of the marine Boom Clay Formation. At most horizons, the concretions consist of ferroan calcite with variable amounts of pyrite, but at stratigraphic level S60 they also contain siderite. S60 is situated at the centre of an intensely bioturbated zone that is underlain by a pyrite-rich layer. Furthermore, the enclosing clay is strongly enriched in iron, manganese and phosphorous. The sedimentological and chemical zoning is indicative for low sedimentation rates, which allowed the concentration of iron in the aerobic zone of the sediment. Concentration of iron was the prerequisite for the formation of the siderite-containing concretions. The co-precipitation with pyrite is an argument for a formation in the sulphate reduction zone, and is indicative for a high rate of iron-reduction. The latter was due to the rapid burial of the iron-enriched layer below the redox boundary. The abrupt fluctuations in sedimentation rate were a response to the maximum flooding event of the second Rupelian third-order relative sea-level cycle, which caused a brief pushback of the detrital sediment wedge to its source areas. As this response is logically explained by the general sequence stratigraphic model [Spec. Publ.-Soc. Econ. Paleontol. Mineral. 42 (1988) 109], early diagenetic siderite may be widespread at maximum flooding surfaces in rapidly prograding marine mudstones.

Anaerobic production of magnetite by a dissimilatory iron-reducing microorganism

USGS Publications Warehouse

Lovley, D.R.; Stolz, J.F.; Nord, G.L.; Phillips, E.J.P.

1987-01-01

The potential contribution of microbial metabolism to the magnetization of sediments has only recently been recognized. In the presence of oxygen, magnetotactic bacteria can form intracellular chains of magnetite while using oxygen or nitrate as the terminal electron acceptor for metabolism1. The production of ultrafine-grained magnetite by magnetotactic bacteria in surficial aerobic sediments may contribute significantly to the natural remanent magnetism of sediments2-4. However, recent studies on iron reduction in anaerobic sediments suggested that bacteria can also generate magnetite in the absence of oxygen5. We report here on a sediment organism, designated GS-15, which produces copious quantities of ultrafine-grained magnetite under anaerobic conditions. GS-15 is not magnetotactic, but reduces amorphic ferric oxide to extracellular magnetite during the reduction of ferric iron as the terminal electron acceptor for organic matter oxidation. This novel metabolism may be the mechanism for the formation of ultrafine-grained magnetite in anaerobic sediments, and couldaccount for the accumulation of magnetite in ancient iron formations and hydrocarbon deposits. ?? 1987 Nature Publishing Group.

Late Eocene diatomite from the Peruvian coastal desert, coastal upwelling in the eastern Pacific, and Pacific circulation before the terminal Eocene event

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

Marty, R.; Dunbar, R.; Martin, J.B.

1988-09-01

Previously undocumented late Eocene diatomaceous sediments are present near Fundo Desbarrancado (FD) in southern Peru. These sediments are similar to Miocene diatomite from the same area but, unlike the Miocene diatomite, the FD sediments contain cherty layers, are enriched in CaCO/sub 3/, have a diverse and abundant radiolarian fauna, and possess varved-massive and millimeter- and meter-scale biogenic-terrigenous alternations. The FD sediments are part of an Eocene sequence that includes the clastic sediments of the Paracas Formation, and they are correlative to the Chira Formation of northern Peru. The Paleogene biogenic sediments of western South America show that coastal upwelling developedmore » in the eastern Pacific before the latest Eocene, argue for the existence of a proto-Humboldt current at this time, and suggest that the terminal Eocene event was the culmination of gradual changes and not a catastrophic event at the Eocene/Oligocene boundary.« less

Characterization of Archaeological Sediments Using Fourier Transform Infrared (FT-IR) and Portable X-ray Fluorescence (pXRF): An Application to Formative Period Pyro-Industrial Sites in Pacific Coastal Southern Chiapas, Mexico.

PubMed

Neff, Hector; Bigney, Scott J; Sakai, Sachiko; Burger, Paul R; Garfin, Timothy; George, Richard G; Culleton, Brendan J; Kennett, Douglas J

2016-01-01

Archaeological sediments from mounds within the mangrove zone of far-southern Pacific coastal Chiapas, Mexico, are characterized in order to test the hypothesis that specialized pyro-technological activities of the region's prehistoric inhabitants (salt and ceramic production) created the accumulations visible today. Fourier transform infrared spectroscopy (FT-IR) is used to characterize sediment mineralogy, while portable X-ray fluorescence (pXRF) is used to determine elemental concentrations. Elemental characterization of natural sediments by both instrumental neutron activation analysis (INAA) and pXRF also contribute to understanding of processes that created the archaeological deposits. Radiocarbon dates combined with typological analysis of ceramics indicate that pyro-industrial activity in the mangrove zone peaked during the Late Formative and Terminal Formative periods, when population and monumental activity on the coastal plain and piedmont were also at their peaks. © The Author(s) 2015.

Appendix D: Use of wave scenarios to assess potential submerged oil mat (SOM) formation along the coast of Florida and Alabama

USGS Publications Warehouse

Dalyander, P. Soupy; Long, Joseph W.; Plant, Nathaniel G.; Thompson, David M.

2013-01-01

During the Deepwater Horizon oil spill, oil in the surf zone mixed with sediment in the surf zone to form heavier-than-water sediment oil agglomerates of various size, ranging from small (cm-scale) pieces (surface residual balls, SRBs) to large mats (100-m scale, surface residue mats, SR mats). Once SR mats formed in the nearshore or in the intertidal zone, they may have become buried by sand moving onshore or alongshore. To assist in locating possible sites of buried oil, wave scenarios previously developed by the U.S. Geological Survey (USGS) were used to determine the depths at which surface oil had the potential to mix with suspended sediment. For sediment to mix with floating oil and form an agglomerate of sufficient density to sink to the seafloor, either the water must be very shallow (e.g., within the swash zone) or sediment must be suspended to the water surface in sufficient concentrations to create a denser-than-sea water agglomerate. The focus of this study is to analyze suspended sediment mixing with surface oil in depths beyond the swash zone, in order to define the seaward limit of mat formation. A theoretical investigation of sediment dynamics in the nearshore zone revealed that non-breaking waves do not suspend enough sediment to the surface to form sinking sand/oil agglomerates. For this study, it was assumed that the cross-shore distribution of potential agglomerate formation is associated with the primary breaker line, and the presence of plunging breakers, over the time frame of oiling. The potential locations of submerged oil mats (SOMs) are sites where (1) possible agglomerate formation occurred, where (2) sediment accreted post-oiling and buried the SOM, and where (3) the bathymetry has not subsequently eroded to re-expose any mat that may have formed at that site. To facilitate identification of these locations, the range of water level variation over the time frame of oiling was also prescribed, which combined with the wave-breaking depth analysis and pre-oiling bathymetry would identify the potential geographic locations of SOMs.

Acetoclastic methane formation from Eucalyptus detritus in pristine hydrocarbon-rich river sediments by Methanosarcinales.

PubMed

Beckmann, Sabrina; Manefield, Mike

2014-12-01

Pristine hydrocarbon-rich river sediments in the Greater Blue Mountains World Heritage Area (Australia) release substantial amounts of methane. The present study aimed to unravel for the first time the active methanogens mediating methane formation and exploiting the bacterial diversity potentially involved in the trophic network. Quantitative PCR of 16S rRNA gene and functional genes as well as 454 pyrosequencing were used to address the unknown microbial diversity and abundance. Methane-releasing sediment cores derived from three different river sites of the Tootie River. Highest methane production rates of 10.8 ± 0.5 μg g(-1)(wet weight) day(-1) were detected in 40 cm sediment depth being in congruence with the detection of the highest abundances of the archaeal 16S rRNA gene and the methyl-coenzyme M reductase (mcrA) genes. Stable carbon and hydrogen isotopic signatures of the produced methane indicated an acetoclastic origin. Long-term enrichment cultures amended with either acetate or H2/CO2 revealed acetoclastic methanogenesis as key methane-formation process mediated by members of the order Methanosarcinales. Conditions prevailing in the river sediments might be suitable for hydrocarbon-degrading bacteria observed in the river sediments that were previously unclassified or closely related to the Bacteroidetes/Chlorobi group, the Firmicutes and the Chloroflexi group fuelling acetoclastic methanogensis in pristine river sediments. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Active hematite concretion formation in modern acid saline lake sediments, Lake Brown, Western Australia

NASA Astrophysics Data System (ADS)

Bowen, Brenda Beitler; Benison, K. C.; Oboh-Ikuenobe, F. E.; Story, S.; Mormile, M. R.

2008-04-01

Concretions can provide valuable records of diagenesis and fluid-sediment interactions, however, reconstruction of ancient concretion-forming conditions can be difficult. Observation of modern hematite concretion growth in a natural sedimentary setting provides a rare glimpse of conditions at the time of formation. Spheroidal hematite-cemented concretions are actively precipitating in shallow subsurface sediments at Lake Brown in Western Australia. Lake Brown is a hypersaline (total dissolved solids up to 23%) and acidic (pH ˜ 4) ephemeral lake. The concretion host sediments were deposited between ˜ 1 and 3 ka, based on dating of stratigraphically higher and lower beds. These age constraints indicate that the diagenetic concretions formed < 3 ka, and field observations suggest that some are currently forming. These modern concretions from Lake Brown provide an example of very early diagenetic formation in acid and saline conditions that may be analogous to past conditions on Mars. Previously, the hematite concretions in the Burns formation on Mars have been interpreted as late stage diagenetic products, requiring long geologic time scales and multiple fluid flow events to form. In contrast, the Lake Brown concretions support the possibility of similar syndepositional to very early diagenetic concretion precipitation on Mars.

Effects of pollution and bioleaching process on the mineral composition and texture of contaminated sediments of the Reconquista River, Argentina.

PubMed

Tufo, Ana E; Porzionato, Natalia F; Curutchet, Gustavo

2017-10-31

In this work, we report on the structural and textural changes in fluvial sediments from Reconquista River´s basin, Argentina, due to processes of contamination with organic matter and remediation by bioleaching. The original uncontaminated matrix showed quartz and phyllosilicates as the main primary mineral constituents and phases of interstratified illite-montmorillonite as secondary minerals. It was found that in contaminated sediments, the presence of organic matter in high concentration causes changes in the specific surface area, particle size distribution, size and distribution of micro and meso, and the morphology of the particles with respect to the uncontaminated sediment. After the bioleaching process, there were even greater changes in these parameters at the level of secondary mineral formation and the appearance of nanoparticles, which were confirmed by SEM. Especially, we found the formation of cementing substances such as gypsum, promoting the formation of macroporous aggregates and the weathering of clay components. Our results indicate that the bioleaching not only decreases the content of metals but also favors the formation of a material with improved characteristics for potential future applications.

Measurements of near-bed intra-wave sediment entrainment above vortex ripples

NASA Astrophysics Data System (ADS)

Thorne, Peter D.; Davies, Alan G.; Williams, Jon J.

2003-10-01

In general, descriptions of suspended sediment transport beneath surface waves are based on the turbulent diffusion concept. However, it is recognised that this approach is questionable for the suspension of sediment when the seabed is rippled. In this case, at least if the ripples are sufficiently steep, the entrainment process is likely to be well organised, and associated with vortex formation and shedding from the ripples. To investigate the entrainment process above ripples, a study was carried out in a large-scale wave flume facility. Utilising acoustic techniques, visualisations of the intra-wave sediment entrainment above vortex ripples have been generated. The observations provide a detailed description of entrainment, which is interpreted here in relation to the process of vortex formation and shedding. It is anticipated that such measurements will contribute to the development of improved physical process models of sediment transport in the rippled bed regime.

Formation and mechanics of granular waves in gravity and shallow overland flow

USDA-ARS?s Scientific Manuscript database

Sediment transport in overland flow is a highly complex process involving many properties relative to the flow regime characteristics, soil surface conditions, and type of sediment. From a practical standpoint, most sediment transport studies are concerned with developing relationships of rates of s...

Sedimentary facies of the upper Cambrian (Furongian; Jiangshanian and Sunwaptan) Tunnel City Group, Upper Mississippi Valley: new insight on the old stormy debate

USGS Publications Warehouse

Eoff, Jennifer D.

2014-01-01

New data from detailed measured sections permit a comprehensive revision of the sedimentary facies of the Furongian (upper Cambrian; Jiangshanian and Sunwaptan stages) Tunnel City Group (Lone Rock Formation and Mazomanie Formation) of Wisconsin and Minnesota. Heterogeneous sandstones, comprising seven lithofacies along a depositional transect from shoreface to transitional-offshore environments, record sedimentation in a storm-dominated, shallow-marine epicontinental sea. The origin of glauconite in the Birkmose Member and Reno Member of the Lone Rock Formation was unclear, but its formation and preserved distribution are linked to inferred depositional energy rather than just net sedimentation rate. Flat-pebble conglomerate, abundant in lower Paleozoic strata, was associated with the formation of a condensed section during cratonic flooding. Hummocky cross-stratification was a valuable tool used to infer depositional settings and relative paleobathymetry, and the model describing formation of this bedform is expanded to address flow types dominant during its genesis, in particular the importance of an early unidirectional component of combined flow. The depositional model developed here for the Lone Rock Formation and Mazomanie Formation is broadly applicable to other strata common to the early Paleozoic that document sedimentation along flooded cratonic interiors or shallow shelves.

Waste Preparation and Transport Chemistry: Results of the FY 2001 Studies

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

Hunt, R.D.

2002-03-25

During FY 2001, tank farm operations at Hanford and the Savannah River Site (SRS) continued to be negatively impacted by the unintended formation of solids. At Hanford, the primary solids formation problem involves a series of plugged pipes and pumps during the saltwell pumping activities of the interim stabilization program. For example, transfers of tank S-102 waste were suspended due to a plugged pipeline or a mechanical problem with the transfer pump. The replacement pump then failed within 2 weeks. In contrast, since full-scale waste remediation activities such as vitrification were initiated, the SRS has encountered a wider range ofmore » problems due to unwanted solids. The 2H evaporator system was shut down because of the formation of aluminosilicate deposits with enriched uranium in the evaporator pot. While high concentrations of aluminum are expected in the tank waste due to previous canyon operations, the primary source of silicon is the recycle stream from the vitrifier. While solids formation can be expected when waste streams are combined, the formation of the aluminosilicate deposits required an elevated temperature within the evaporator. The shutdown of the 2H evaporator led to a severe shortage of tank space. Therefore, the SRS tank farm was forced to transfer highly concentrated waste, which led to a plugged transfer pump in tank 32. For each of the proposed cesium removal technologies for the SRS, unwanted solids formation occurred during the large laboratory-scale tests prior to the final selection of the solvent extraction process. It can be expected that further problems will be encountered as more unit operations of the remediation effort are deployed and as more waste streams are combined. Since these problems have already led to costly schedule delays, the tank farm operators at both sites have identified the prevention of solids formation as a high-priority need. In response to this need, the Tank Focus Area has assembled a team of researchers of researchers from AEA Technology, Florida International University (FIU), Fluor Hanford, Mississippi State University (MSU), Oak Ridge National Laboratory (ORNL), and Savannah River Technology Center (SRTC) to evaluate various aspects of the waste preparation and transport chemistry. The majority of this effort was focused on saltcake dissolution and saltwell pumping. The results of the AEA Technology, FIU, and MSU studies of saltcake dissolution and slurry transfers for Hanford are discussed in detail in a companion report prepared by T. D. Welch in 2001 (ORNIJTM-2001097). Staff members at Fluor Hanford have continued to conduct saltcake dissolution tests on actual tank waste (documented in reports prepared by D. L. Herting in 2000 and 2001). It should be noted that full-scale saltcake dissolution at Hanford is scheduled to begin in FY 2002. While the Hanford effort is focused on the transfer of waste from one tank to another, the objective of the SRTC study is the formation of aluminosilicates at elevated temperatures, which are present in the waste evaporator.« less

Hydrocarbons in recent sediment of the Monterey Bay National Marine Sanctuary

USGS Publications Warehouse

Kvenvolden, K.A.; Hostettler, F.D.; Rosenbauer, R.W.; Lorenson, T.D.; Castle, W.T.; Sugarman, S.

2002-01-01

A complex mixture of hydrocarbons is present in the recent sediment of the Monterey Bay National Marine Sanctuary. Eighteen samples from the continental shelf between San Francisco and Monterey contain aliphatic and aromatic hydrocarbons showing biological contributions from both marine and terrigenous sources, with the terrigenous indicators more pronounced near Monterey. Of particular interest, however, is a low-level background of petroleum-related compounds, including 28,30-bisnorhopane and 18??+??(H)-oleanane, which are characteristic of many crude oils from the Monterey Formation of California. Thus, the sediments are overprinted by a regional chemical signature which may be derived from eroded Monterey Formation rocks and from onshore and offshore seeps releasing petroleum from Monterey Formation source rocks. ?? 2002 Elsevier Science B.V. All rights reserved.

The effect of removing plugs and adding arch support to foam based insoles on plantar pressures in people with diabetic peripheral neuropathy.

PubMed

Lin, Tung-Liang; Sheen, Huey-Min; Chung, Chin-Teng; Yang, Sai-Wei; Lin, Shih-Yi; Luo, Hong-Ji; Chen, Chung-Yu; Chan, I-Cheng; Shih, Hsu-Sheng; Sheu, Wayne Huey-Herng

2013-07-29

Removable plug insoles appear to be beneficial for patients with diabetic neuropathic feet to offload local plantar pressure. However, quantitative evidence of pressure reduction by means of plug removal is limited. The value of additional insole accessories, such as arch additions, has not been tested. The purpose of this study was to evaluate the effect of removing plugs from foam based insoles, and subsequently adding extra arch support, on plantar pressures. In-shoe plantar pressure measurements were performed on 26 patients with diabetic neuropathic feet at a baseline condition, in order to identify the forefoot region with the highest mean peak pressure (MPP). This was defined as the region of interest (ROI) for plug removal.The primary outcome was measurement of MPP using the pedar® system in the baseline and another three insole conditions (pre-plug removal, post-plug removal, and post-plug removal plus arch support). Among the 26 ROIs, a significant reduction in MPP (32.3%, P<0.001) was found after removing the insole plugs. With an arch support added, the pressure was further reduced (9.5%, P<0.001). There were no significant differences in MPP at non-ROIs between pre- and post-plug removal conditions. These findings suggest that forefoot plantar pressure can be reduced by removing plugs and adding arch support to foam-based insoles. This style of insole may therefore be clinically useful in managing patients with diabetic peripheral neuropathy.

Post-depositional formation of vivianite-type minerals alters sediment phosphorus records

NASA Astrophysics Data System (ADS)

Dijkstra, Nikki; Hagens, Mathilde; Egger, Matthias; Slomp, Caroline P.

2018-02-01

Phosphorus (P) concentrations in sediments are frequently used to reconstruct past environmental conditions in freshwater and marine systems, with high values thought to be indicative of a high biological productivity. Recent studies suggest that the post-depositional formation of vivianite, an iron(II)-phosphate mineral, might significantly alter trends in P with sediment depth. To assess its importance, we investigate a sediment record from the Bornholm Basin that was retrieved during the Integrated Ocean Drilling Program (IODP) Baltic Sea Paleoenvironment Expedition 347 in 2013, consisting of lake sediments overlain by brackish-marine deposits. Combining bulk sediment geochemistry with microanalysis using scanning electron microscope energy dispersive spectroscopy (SEM-EDS) and synchrotron-based X-ray absorption spectroscopy (XAS), we demonstrate that vivianite-type minerals rich in manganese and magnesium are present in the lake deposits just below the transition to the brackish-marine sediments (at 11.5 to 12 m sediment depth). In this depth interval, phosphate that diffuses down from the organic-rich, brackish-marine sediments meets porewaters rich in dissolved iron in the lake sediments, resulting in the precipitation of iron(II) phosphate. Results from a reactive transport model suggest that the peak in iron(II) phosphate originally occurred at the lake-marine transition (9 to 10 m) and moved downwards due to changes in the depth of a sulfidization front. However, its current position relative to the lake-marine transition is stable as the vivianite-type minerals and active sulfidization fronts have been spatially separated over time. Experiments in which vivianite was subjected to sulfidic conditions demonstrate that incorporation of manganese or magnesium in vivianite does not affect its susceptibility to sulfide-induced dissolution. Our work highlights that post-depositional formation of iron(II) phosphates such as vivianite has the potential to strongly alter sedimentary P records particularly in systems that are subject to environmental perturbation, such as a change in primary productivity, which can be associated with a lake-marine transition.

Sedimentation, bioturbation, and sedimentary fabric evolution on a modern mesotidal mudflat: A multi-tracer study of processes, rates, and scales

NASA Astrophysics Data System (ADS)

Bentley, Samuel J.; Swales, Andrew; Pyenson, Benjamin; Dawe, Justin

2014-03-01

A study of muddy tidal-flat sedimentation and bioturbation was undertaken in the Waitetuna Arm of Raglan Harbor, New Zealand, to evaluate the physical and biological processes that control cycling of sediment between the intertidal seabed and sediment-water interface, and also the formation of tidal flat sedimentary fabric and fine-scale stratigraphy. Cores were collected along an intertidal transect, and analyzed for sedimentary fabric, 210Pb and 7Be radiochemical distributions, and grain size. At the same locations, a new approach for time-series core-X-radiography study was undertaken (spanning 191 days), using magnetite-rich sand as a tracer for sedimentation and bioturbation processes in shallow tidal flat sediments. Sedimentary fabric consists of a shallow stratified layer overlying a deeper zone of intensely bioturbated shelly mud. Bioadvection mixes the deeper zone and contributes fine sediment to the surface stratified layer, via biodeposition. Physical resuspension and deposition of surface muds by wave and tidal flow are also likely contributors to formation of the surficial stratified layer, but physical stratification is not observed below this depth. The deliberate tracer study allowed calculation of bioadvection rates that control strata formation, and can be used to model diagenetic processes. Results suggest that the upper ˜15 cm of seabed can be fully mixed over timescales <1.75 y. Such mixing will erase pre-existing sedimentary fabric and transport buried sediment and chemical compounds back to the tidal-flat surface. Shallow biodiffusion also exists, but produces much slower and shallower mass transport. Best fits for 210Pb profiles using a diagenetic bioadvection/sedimentation model and independently measured tiered bioadvection rates suggest that sediment accumulation rates (SARs) on the tidal flat are ˜0.25 cm/y, near the low end of contemporary New Zealand muddy intertidal SARs. Frequent deposition and erosion of the surface layer demonstrates that long-term sediment accumulation captures only a small fraction of sediment deposited at any one time. Model results also suggest that our magnetite tracer method may slightly underestimate short-term shallow mixing rates (demonstrated by 7Be profiles), and slightly overestimate longer-term, deeper bioturbation rates (demonstrated by 210Pb profiles).

TR-596 insights into the origin and characteristics of the sedimentation process at multi-barrel culverts in Iowa.

DOT National Transportation Integrated Search

2010-06-01

The present study is an integral part of a broader study focused on the design and implementation of self-cleaning culverts, i.e., : configurations that prevent the formation of sediment deposits after culvert construction or cleaning. Sediment depos...

Biomass plug development and propagation in porous media.

PubMed

Stewart, T L; Fogler, H S

2001-02-05

Exopolymer-producing bacteria can be used to modify soil profiles for enhanced oil recovery or bioremediation. Understanding the mechanisms associated with biomass plug development and propagation is needed for successful application of this technology. These mechanisms were determined from packed-bed and micromodel experiments that simulate plugging in porous media. Leuconostoc mesenteroides was used, because production of dextran, a water-insoluble exopolymer, can be controlled by using different carbon sources. As dextran was produced, the pressure drop across the porous media increased and began to oscillate. Three pressure phases were identified under exopolymer-producing conditions: the exopolymer-induction phase, the plugging phase, and the plug-propagation phase. The exopolymer-induction phase extended from the time that exopolymer-producing conditions were induced until there was a measurable increase in pressure drop across the porous media. The plugging phase extended from the first increase in pressure drop until a maximum pressure drop was reached. Changes in pressure drop in these two phases were directly related to biomass distribution. Specifically, flow channels within the porous media filled with biomass creating a plugged region where convective flow occurred only in water channels within the biofilm. These water channels were more restrictive to flow causing the pressure drop to increase. At a maximum pressure drop across the porous media, the biomass yielded much like a Bingham plastic, and a flow channel was formed. This behavior marked the onset of the plug-propagation phase which was characterized by sequential development and breakthrough of biomass plugs. This development and breakthrough propagated the biomass plug in the direction of nutrient flow. The dominant mechanism associated with all three phases of plugging in porous media was exopolymer production; yield stress is an additional mechanism in the plug-propagation phase. Copyright 2001 John Wiley & Sons, Inc.

75 FR 16657 - Airworthiness Directives; Airbus Model A300 B2-1C, B2K-3C, B2-203, B4-2C, B4-103, and B4-203...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-02

... phasing inspections and magnetic plug inspections for metal particles on the drain plug using detailed... inspections and magnetic plug inspections for metal particles on the drain plug using detailed inspection..., but the magnetic plug inspection reveals metal particles with dimensions greater than 1.5 mm (0.059 in...

GDAL Enhancements for Interoperability with EOS Data (GEE)

NASA Astrophysics Data System (ADS)

Tisdale, B.

2015-12-01

Historically, Earth Observing Satellite (EOS) data products have been difficult to consume by GIS tools, weather commercial or open-source. This has resulted in a reduced acceptance of these data products by GIS and general user communities. Common problems and challenges experienced by these data users include difficulty when: Consuming data products from NASA Distributed Active Archive Centers (DAACs) that pre-date modern application software with commercial and open-source geospatial tools; Identifying[MI1] an initial approach for developing a framework and plug-ins that interpret non-compliant data; Defining a methodology that is extensible across NASA Earth Observing System Data and Information System (EOSDIS), scientific communities, and GIS communities by enabling other data centers to construct their own plug-ins and adjust specific data products; and Promoting greater use of NASA Data and new analysis utilizing GIS tools. To address these challenges and make EOS data products more accessible and interpretable by GIS applications, a collaborative approach has been taken that includes the NASA Langley Atmospheric Science Data Center (ASDC), Esri, George Mason University (GMU), and the Hierarchical Data Format (HDF) Group to create a framework and plugins to be applied to Geospatial Data Abstraction Library (GDAL). This framework and its plugins offer advantages of extensibility within NASA EOSDIS, permitting other data centers to construct their own plugins necessary to adjust their data products. In this session findings related to the framework and the development of GDAL plugins will be reviewed. Specifically, this session will offer a workshop to review documentation and training materials that have been generated for the purpose of guiding other NASA DAACs through the process of constructing plug-ins consistent with the framework as well as a review of the certification process by which the plugins can be independently verified as properly converting the data to the format and content required for use in GIS software.

GDAL Enhancements for Interoperability with EOS Data

NASA Astrophysics Data System (ADS)

Tisdale, M.; Mathews, T. J.; Tisdale, B.; Sun, M.; Yang, C. P.; Lee, H.; Habermann, T.

2015-12-01

Historically, Earth Observing Satellite (EOS) data products have been difficult to consume by GIS tools, weather commercial or open-source. This has resulted in a reduced acceptance of these data products by GIS and general user communities. Common problems and challenges experienced by these data users include difficulty when: Consuming data products from NASA Distributed Active Archive Centers (DAACs) that pre-date modern application software with commercial and open-source geospatial tools; Identifying an initial approach for developing a framework and plug-ins that interpret non-compliant data; Defining a methodology that is extensible across NASA Earth Observing System Data and Information System (EOSDIS), scientific communities, and GIS communities by enabling other data centers to construct their own plug-ins and adjust specific data products; and Promoting greater use of NASA Data and new analysis utilizing GIS tools. To address these challenges and to make EOS data products more accessible and interpretable by GIS applications, a collaborative approach has been taken that includes the NASA Langley Atmospheric Science Data Center (ASDC), Esri, George Mason University (GMU), and the Hierarchical Data Format (HDF) Group to create a framework and plugins to be applied to Geospatial Data Abstraction Library (GDAL). This framework and its plugins offer advantages of extensibility within NASA EOSDIS, permitting other data centers to construct their own plugins necessary to adjust their data products. In this session findings related to the framework and the development of GDAL plugins will be reviewed. Specifically, this session will offer a workshop to review documentation and training materials that have been generated for the purpose of guiding other NASA DAACs through the process of constructing plug-ins consistent with the framework as well as a review of the certification process by which the plugins can be independently verified as properly converting the data to the format and content required for use in GIS software.

40 CFR 144.63 - Financial assurance for plugging and abandonment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... current plugging and abandonment cost estimate, except as provided in § 144.70(g), divided by the number... days after receiving bills for plugging and abandonment activities, the Regional Administrator will... abandonment activities, the Regional Administrator will determine whether the plugging and abandonment...

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

Feder, Russell; Youssef, Mahamoud; Klabacha, Jonathan

USITER is one of seven partner domestic agencies (DA) contributing components to the ITER project. Four diagnostic port plug packages (two equatorial ports and two upper ports) will be engineered and fabricated by Princeton Plasma Physics Lab (PPPL). Diagnostic port plugs as illustrated in Fig. 1 are large primarily stainless steel structures that serve several roles on ITER. The port plugs are the primary vacuum seal and tritium confinement barriers for the vessel. The port plugs also house several plasma diagnostic systems and other machine service equipment. Finally, each port plug must shield high energy neutrons and gamma photons frommore » escaping and creating radiological problems in maintenance areas behind the port plugs. The optimization of the balance between adequate shielding and the need for high performance, high throughput diagnostics systems is the focus of this paper. Neutronics calculations are also needed for assessing nuclear heating and nuclear damage in the port plug and diagnostic components. Attila, the commercially available discrete-ordinates software package, is used for all diagnostic port plug neutronics analysis studies at PPPL.« less

Assessing the role of clay authigenesis in the seawater potassium cycle: A paired K and Mg isotope study of deep-sea pore fluids

NASA Astrophysics Data System (ADS)

Santiago Ramos, D. P.; Higgins, J. A.

2017-12-01

In situ formation of clays (clay authigenesis) in marine sediments and altered oceanic crust is an important sink of a number of seawater cations. In particular, clay authigenesis is a major, and yet unconstrained, flux in the global seawater potassium cycle. Potassium is the fourth most abundant cation in the ocean, which constitutes an isotopically enriched K reservoir (δ41K 0‰) compared to the solid Earth (δ41K -0.5‰). Understanding what processes control this isotopic offset is the main goal of this study. Here we use a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) to measure the K and Mg isotope ratios (41K/39K and 26Mg/24Mg) of deep-sea pore fluids in order to assess the effects of clay formation in the K isotope composition of seawater. Mg isotopes are used as an independent proxy for clay formation, since marine authigenic clays are isotopically distinct from their detrital counterpart, an abundant component of marine sediments. Our study sites (ODP/IODP 1052, U1378, U1395, U1403) vary in location, lithology, age and sedimentation rates; however, pore-fluids from all sites show decreasing K concentrations with depth, suggesting potassium uptake into the sediments. We find that although K concentration trends are similar across all sites, measured δ41K values vary significantly. Results from 1-D diffusion-advection-reaction models suggest that these differences in isotopic profiles arise from a complex interplay between sedimentation rate and K isotopic fractionation during clay formation, aqueous K diffusion and ion exchange reactions. Further, model simulations yield fractionation factors between 0.9980 and 1.0000 for clay formation in deep-sea sediments. Despite the minor contribution of these deep-sea pore-fluids as sinks of seawater K, the processes responsible for K isotope fractionation in our study sites (clay formation and aqueous K diffusion) are also observed at shallow marine systems (major K sinks) and are thus likely responsible for setting the K isotopic composition of seawater.

Safety and Efficacy of Lacrimal Drainage System Plugs for Dry Eye Syndrome: A Report by the American Academy of Ophthalmology.

PubMed

Marcet, Marcus M; Shtein, Roni M; Bradley, Elizabeth A; Deng, Sophie X; Meyer, Dale R; Bilyk, Jurij R; Yen, Michael T; Lee, W Barry; Mawn, Louise A

2015-08-01

To review the published literature assessing the efficacy and safety of lacrimal drainage system plug insertion for dry eye in adults. Literature searches of the PubMed and Cochrane Library databases were last conducted on March 9, 2015, without date restrictions and were limited to English language abstracts. The searches retrieved 309 unique citations. The primary authors reviewed the titles and abstracts. Inclusion criteria specified reports that provided original data on plugs for the treatment of dry eyes in at least 25 patients. Fifty-three studies of potential relevance were assigned to full-text review. The 27 studies that met the inclusion criteria underwent data abstraction by the panels. Abstracted data included study characteristics, patient characteristics, plug type, insertion technique, treatment response, and safety information. All studies were observational and rated by a methodologist as level II or III evidence. The plugs included punctal, intracanalicular, and dissolving types. Fifteen studies reported metrics of improvement in dry eye symptoms, ocular-surface status, artificial tear use, contact lens comfort, and tear break-up time. Twenty-five studies included safety data. Plug placement resulted in ≥50% improvement of symptoms, improvement in ocular-surface health, reduction in artificial tear use, and improved contact lens comfort in patients with dry eye. Serious complications from plugs were infrequent. Plug loss was the most commonly reported problem with punctal plugs, occurring on average in 40% of patients. Overall, among all plug types, approximately 9% of patients experienced epiphora and 10% required removal because of irritation from the plugs. Canaliculitis was the most commonly reported problem for intracanalicular plugs and occurred in approximately 8% of patients. Other complications were reported in less than 4% of patients on average and included tearing, discomfort, pyogenic granuloma, and dacryocystitis. On the basis of level II and III evidence in these studies, plugs improve the signs and symptoms of moderate dry eye that are not improved with topical lubrication, and they are well tolerated. There are no level I studies that describe the efficacy or safety of lacrimal drainage system plugs. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Paleogeography and Depositional Systems of Cretaceous-Oligocene Strata: Eastern Precordillera, Argentina

NASA Astrophysics Data System (ADS)

Reat, Ellen J.; Fosdick, Julie C.

2016-04-01

New data from the Argentine Precordillera in the southern Central Andes document changes in depositional environment and sediment accumulation rates during Upper Cretaceous through Oligocene basin evolution, prior to the onset Miocene foredeep sedimentation. This work presents new sedimentology, detrital geochronology, and geologic mapping from a series of continental strata within this interval to resolve the timing of sedimentation, nature of depositional environments, and basin paleogeography at the nascent phase of Andean orogenic events, prior to the uplift and deformation of the Precordillera to the west. Five stratigraphic sections were measured across both limbs of the Huaco Anticline, detailing sedimentology of the terrestrial siliciclastic upper Patquía, Ciénaga del Río Huaco (CRH), Puesto la Flecha, Vallecito, and lower Cerro Morado formations. Paleocurrent data indicate a flow direction change from predominantly NE-SW in the upper Patquía and the lower CRH to SW-NE directed flow in the upper CRH, consistent with a large meandering river system and a potential rise in topography towards the west. This interpretation is further supported by pebble lag intervals and 1-3 meter scale trough cross-bedding in the CRH. The thinly laminated gypsum deposits and siltstones of the younger Puesto la Flecha Formation indicate an upsection transition into overbank and lacustrine sedimentation during semi-arid climatic conditions, before the onset of aeolian dune formation. New maximum depositional age results from detrital zircon U-Pb analysis indicate that the Puesto la Flecha Formation spans ~57 Myr (~92 to ~35 Ma) across a ~48 m thick interval without evidence for major erosion, indicating very low sedimentation rates. This time interval may represent distal foredeep or forebulge migration resultant from western lithospheric loading due to the onset of Andean deformation at this latitude. Detrital zircon U-Pb age spectra also indicate shifts in sediment routing pathways over time, consistent with a transition from local basement-sourced quartz-rich sediments during the Triassic-Cretaceous to increased volcanic and sedimentary lithics from the rising Andes in the west during Paleocene-Eocene time. We therefore interpret these changes in depositional character as representing a transition from a large fluvial system with craton-sourced sediments during the Triassic-Cretaceous CRH to low energy lacustrine and ephemeral playa environments with an increase in westerly derived sediments during the Paleocene-Eocene Puesto la Flecha, prior to the reported Oligocene onset of the Andean continental foredeep represented by the Vallecito Formation.

The formation mechanisms of turbidity maximum in the Pearl River estuary, China.

PubMed

Wai, O W H; Wang, C H; Li, Y S; Li, X D

2004-03-01

The formation and dynamics of turbidity maxima (TM) in the Pearl River estuary (PRE) are not well understood but the existence of TM in the estuary have great potential engineering and environmental impacts. Based on the measurements of two large-scale field surveys conducted in the wet season of 1978 (July of 1978) and the dry season of 1979 (March of 1979), the existence and seasonal variations of TM in the PRE focusing on the two major natural navigation channels have been studied. The sediment transport fluxes over two consecutive tidal cycles have been analyzed in detail. The analysis results reveal that the formation mechanisms of TM in the estuary are rather complex. In general, gravitational circulation, tidal trapping, and sediment resuspension and deposition processes are the primary TM formation mechanisms in the PRE. The clockwise back flow pattern around Lingding Island also leads to the formation of TM in the West channel of the PRE. The occurrence of TM far upstream of the salt water wedge is the result of the complex hydrodynamic and sediment transport processes generated by the runoff of the major rivers.

Aromatic Radicals-Acetylene Particulate Matter Chemistry

DTIC Science & Technology

2011-12-01

in the fuel itself. For example, alkylated aromatic hydrocarbons form major constituents of gasoline, diesel and jet fuels due to their high energy... jet stirred reactor data at stoichiometric conditions the model shows greater consumption of fuel , oxygen and earlier formation of the intermediates...reaction time of 0.1s, which are the typical reaction times for complete conversion of the fuel in a plug flow reactor or the residence time in a jet

Phosphate mineral formation in Lake Baikal sediments and implications for paleoclimate

NASA Astrophysics Data System (ADS)

Fagel, N.; Alleman, L. Y.; André, L.; Cloots, R.; Hatert, F.; Juvigné, E.; Renson, V.

2003-04-01

The more than 20 million years old Lake Baikal sedimentary record provides a good climate archive. While most paleoclimate reconstructions are mainly based on biotic proxies, we tested in this study other minerogenic tracers. In particular, it was suggested that the formation of authigenic and/or diagenetic phosphate minerals in Baïkal sediments underlines transitions from glacial to interglacial periods (Deike et al., 1997). The phosphate mineral formation previously evidenced (Müller et al., 2002) may be sensitive to suspended sediment concentrations: glacial periods are characterised by high detrital discharge, interglacial intervals are marked by low detrital supply but high biogenic sedimentation. Phosphate minerals were observed in Baïkal sediments from recent to 65 kyr BP. Their abundance was related to the sedimentation rate, the phosphate enrichment layers being particularly common on low sedimentation site, i.e., the Academician Ridge. Major and trace elements have been analysed by ICP-AES and ICP-MS on four cores drilled on topographic hills, in the southern basin (Posolsky bank, CON01-604), in the central part (Academician Ridge, VER98-1-3 and VER98-1-14) and in the northern basin (Continent Ridge, CON01-603). The geochemical signature is consistent with the occurrence of Mn-Fe-phosphate minerals. For instance P2O5 reaches up to 3% wt. relative to a mean value of 0.3 in the background sediment, MnO2 presents an enrichment factor up to 6. There is no associated enrichment in any of the trace elements measured at the same levels. In the sediments, those P-Mn-Fe rich levels are related either to sparse millimetric dark concretions or to a layer (or a group of layers) defined by an alignment of numerous concretions but there is no so-called crusts. The concretions, isolated by >63 mm sieving, present a lamellar morphology. They are identified as Fe-phosphate phases with a variable proportion of Mn. The powder diffraction diagram is consistent with vivianite, a mineral that has been previously characterized in lacustrine sediments worldwide, including Baïkal. However, its precise formation process is not yet fully understood. Dean et al. (2002) emphasize that the occurrence of phosphate minerals in Elk lake (USA) is indicative of the paleo-productivity of the water-column. For Deike et al. (2002), phosphate crusts mainly accumulate under slow sedimentation conditions. We discuss the paleo-environmental implications of the occurrence of phosphate minerals in sediments. By studying the distribution of the phosphate concretions in sedimentary columns characterised under different sedimentary conditions, we would like to point up the implications of phosphate minerals for paleoclimate reconstruction. Dean et al., 2002. A 1500-year record of climatic and environmental change in Elk Lake, Cearwater County, Minnesota II : Geochemistry , mineralogy, and stable isotopes. J. Paleolimn. 27, 301-319. Müller et al., 2002. P, As, Sb, Mo, and other elements in sedimentary Fe/Mn layers of Lake Baïkal, Environmental Science and Technology, 36, 411-420. Deike et al., 1997. Formation of ferric iron crusts in quaternnary sediments of Lake Baikal, Russia and implications for paleoclimate. Marine Geology 139, 21-46.

Quantifying porosity and permeability of fractured carbonates and fault rocks in natural groundwater reservoirs

NASA Astrophysics Data System (ADS)

Pirmoradi, Reza; Wolfmayr, Mariella; Bauer, Helene; Decker, Kurt

2017-04-01

This study presents porosity and permeability data for a suite of different carbonate rocks from two major groundwater reservoirs in eastern Austria that supply more than 60% of Vienna`s drinking water. Data includes a set of lithologically different, unfractured host rocks, fractured rocks with variable fracture intensities, and fault rocks such as dilation breccias, different cataclasites and dissolution-precipitation fault rocks. Fault rock properties are of particular importance, since fault zones play an important role in the hydrogeology of the reservoirs. The reservoir rocks are exposed at two major alpine karst plateaus in the Northern Calcareous Alps. They comprise of various Triassic calcareous strata of more than 2 km total thickness that reflect facies differentiation since Anisian times. Rocks are multiply deformed resulting in a partly dense network of fractures and faults. Faults differ in scale, fault rock content, and fault rock volumes. Methods used to quantify the porosity and permeability of samples include a standard industry procedure that uses the weight of water saturated samples under hydrostatic uplift and in air to determine the total effective (matrix and fracture) porosity of rocks, measurements on plugs with a fully automated gas porosity- and permeameter using N2 gas infiltrating plugs under a defined confining pressure (Coreval Poro 700 by Vinci technologies), and percolation tests. The latter were conducted in the field along well known fault zones in order to test the differences in fractured rock permeability in situ and on a representative volume, which is not ensured with plug measurements. To calculate hydraulic conductivity by the Darcy equation the measured elapsed time for infiltrating a standard volume of water into a small borehole has been used. In general, undisturbed host rock samples are all of low porosity (average around 1%). The open porosity of the undisturbed rocks belonging to diverse formations vary from 0.18% to 2.35%. Klinkenberg permeabilities of plugs range from 0.001mD to about 0.6mD thus spreading over three orders of magnitude. Fractured rocks show significantly higher porosities (3% average) with respect to the undeformed country rocks. Plug measurements reveal quite low permeabilities (< 1mD) for this type of rock, which is owed to the measuring technique, where fractures are closed under confining pressure. A second important point is that intensely fractured rocks are underrepresented in the data as they cannot be plugged adequately. Percolation tests give better information for fractured rock permeabilities and revealed hydraulic conductivities of 10-6 m/sec for little fractured to 5x10-5 m/sec for intensely fractured rocks. Plug and rock sample data show that cataclastic fault rocks can have quite high porosities (up to 4.1%). However, plug permeabilities down to 0.03mD demonstrate that pores are too small to result in any significant permeability. Breccias show high porosities of 4% in average and very variable permeabilities between 2.2mD and 2214mD depending mainly on the degree of cementation.

Time-Reversal Based Range Extension Technique for Ultra-Wideband (UWB) Sensors and Applications in Tactical Communications and Networking

DTIC Science & Technology

2009-07-16

Frequency (MHz) Figure 3.4: CABLE SMA/SMA 24" RG-316DS. CABLE SMA PLUG-PLUG HF -.086 8" 3.1. TRANSMITTER IMPLEMENTATION 13 Length: 8.0" (203.2mm) Color...Gray RG Type: Hand Formable .086 Connector: Type SMA Male to SMA Male Features: Shielded "• JI Figure 3.5: CABLE SMA PLUG-PLUG HF -.086 8...34 . • CABLE SMA PLUG-PLUG HF -.141 8" Length: 8.0" (203.2mm) Color: Gray RG Type: Hand Formable .141 14 CHAPTER 3. 2 BY I MISO SYSTEM DEVELOPMENT

Hot cell shield plug extraction apparatus

DOEpatents

Knapp, Philip A.; Manhart, Larry K.

1995-01-01

An apparatus is provided for moving shielding plugs into and out of holes in concrete shielding walls in hot cells for handling radioactive materials without the use of external moving equipment. The apparatus provides a means whereby a shield plug is extracted from its hole and then swung approximately 90 degrees out of the way so that the hole may be accessed. The apparatus uses hinges to slide the plug in and out and to rotate it out of the way, the hinge apparatus also supporting the weight of the plug in all positions, with the load of the plug being transferred to a vertical wall by means of a bolting arrangement.

3D CFD Simulation of Plug Dynamics and Splitting through a Bifurcating Airway Model

NASA Astrophysics Data System (ADS)

Hoi, Cory; Raessi, Mehdi

2017-11-01

Respiratory distress syndrome (RDS) occurs because of pulmonary surfactant insufficiency in the lungs of preterm infants. The common medical procedure to treat RDS, called surfactant respiratory therapy (SRT), involves instilling liquid surfactant plugs into the pulmonary airways. SRT's effectiveness highly depends on the ability to deliver surfactant through the complex branching airway network. Experimental and computational efforts have been made to understand complex fluid dynamics of liquid plug motion through the lung airways in order to increase SRT's response rate. However, previous computational work used 2D airway model geometries and studied plug dynamics of a pre-split plug. In this work, we present CFD simulations of surfactant plug motion through a 3D bifurcating airway model. In our 3D y-tube geometry representing the lung airways, we are not limited by 2D or pre-split plug assumptions. The airway walls are covered with a pre-existing liquid film. Using a passive scalar marking the surfactant plug, the plug splitting and surfactant film deposition is studied under various airway orientations. Exploring the splitting process and liquid distribution in a 3D geometry will advance our understanding of surfactant delivery and will increase the effectiveness of SRT.

Effects of Proud Large Osteochondral Plugs on Contact Forces and Knee Kinematics: A Robotic Study.

PubMed

Du, Peter Z; Markolf, Keith L; Boguszewski, Daniel V; Yamaguchi, Kent T; Lama, Christopher J; McAllister, David R; Jones, Kristofer J

2018-05-01

Osteochondral allograft (OCA) transplantation is used to treat large focal femoral condylar articular cartilage defects. A proud plug could affect graft survival by altering contact forces (CFs) and knee kinematics. A proud OCA plug will significantly increase CF and significantly alter knee kinematics throughout controlled knee flexion. Controlled laboratory study. Human cadaver knees had miniature load cells, each with a 20-mm-diameter cylinder of native bone/cartilage attached at its exact anatomic position, installed in both femoral condyles at standardized locations representative of clinical defects. Spacers were inserted to create proud plug conditions of +0.5, +1.0, and +1.5 mm. CFs and knee kinematics were recorded as a robot flexed the knee continuously from 0° to 50° under 1000 N of tibiofemoral compression. CFs were increased significantly (vs flush) for all proudness conditions between 0° and 45° of flexion (medial) and 0° to 50° of flexion (lateral). At 20°, the average increases in medial CF for +0.5-mm, +1-mm, and +1.5-mm proudness were +80 N (+36%), +155 N (+70%), and +193 N (+87%), respectively. Corresponding increases with proud lateral plugs were +44 N (+14%), +90 N (+29%), and +118 N (+38%). CF increases for medial plugs at 20° of flexion were significantly greater than those for lateral plugs at all proudness conditions. At 50°, a 1-mm proud lateral plug significantly decreased internal tibial rotation by 15.4° and decreased valgus rotation by 2.5°. A proud medial or lateral plug significantly increased CF between 0° and 45° of flexion. Our results suggest that a medial plug at 20° may be more sensitive to graft incongruity than a lateral plug. The changes in rotational kinematics with proud lateral plugs were attributed to earlier contact between the proud plug's surface and the lateral meniscus, leading to rim impingement with decreased tibial rotation. Increased CF and altered knee kinematics from a proud femoral plug could affect graft viability. Plug proudness of only 0.5 mm produced significant changes in CF and knee kinematics, and the clinically accepted 1-mm tolerance may need to be reexamined in view of our findings.

Formation and preservation of greigite (Fe3S4) in a thick sediment layer from the central South Yellow Sea

NASA Astrophysics Data System (ADS)

Liu, Jianxing; Mei, Xi; Shi, Xuefa; Liu, Qingsong; Liu, Yanguang; Ge, Shulan

2018-04-01

Sediments from continental shelves are sensitive to changes in both oceanic and terrestrial conditions, and, therefore, magnetic minerals in such sediments are affected strongly by depositional and diagenetic processes. Here, we investigated systematically an N-S transect of three sediment cores from the central South Yellow Sea (SYS) muddy area. Magnetic data indicate the presence of a horizontally distributed thick greigite-bearing layer. From an age model based on published magnetostratigraphy, accelerator mass spectrometry 14C dating ages, sedimentary characteristics and foraminiferal analysis, this layer was deposited within marine isotope stages (MIS) 17-13, following an enhanced sulphidic period over MIS 21-19 when the YS Warm Current and the associated YS Cold Water Mass were strong and where underlying sediments have higher total organic carbon, total sulphur and trace element molybdenum contents. Trace element cadmium enrichment in the greigite-bearing layers is documented for the first time, which indicates that weakly sulphidic (i.e. with trace levels of free H2S) conditions existed before greigite formed in a sulphidic environment during early diagenesis. It also indicates that subsequent conditions free of oxygen and H2S after greigite formation are more favourable for its preservation. We propose that organic matter supply was controlled over an extended period by moderate primary productivity. The combined effects of palaeoclimate and local tectonic subsidence were crucial for the formation and preservation of the identified greigite. In brief, our study improves understanding of the formation and preservation mechanisms of greigite in continental shelf sediments and reveals mid-Pleistocene palaeoenvironmental changes in the SYS.

Integrated stratigraphy of Paleocene lignite seams of the fluvial Tullock Formation, Montana (USA).

NASA Astrophysics Data System (ADS)

Noorbergen, Lars J.; Kuiper, Klaudia F.; Hilgen, Frederik J.; Krijgsman, Wout; Dekkers, Mark J.; Smit, Jan; Abels, Hemmo A.

2015-04-01

Coal-bearing fluvial sedimentation is generally thought to be dominated by autogenic processes that are processes intrinsic to the sedimentary system. Ongoing research however suggests that several fluvial processes such as floodplain inundation and avulsion, can also be controlled by external forcing such as orbital climate change. Still, the exact role of orbital climate forcing in fluvial sediments is difficult to decipher since riverine deposits are complicated by variable sedimentation rates including erosion of previously deposited material, by lateral heterogeneity of sedimentation, and by scarcity of independent dating methods. The early Paleocene lignite-bearing Tullock Formation of the Williston Basin in eastern Montana represents a record of fluvial sedimentation that is perfectly exposed and, displays a seemingly regular alternation of sandstones and lignite seams. These coal beds contain multiple volcanic ash layers. Here, we use an integrated stratigraphic approach (litho- and magnetostratigraphy, geochemical fingerprinting and radio-isotope dating of volcanic ash layers) to establish a high-resolution time frame for the early Paleocene fluvial sediments. First age estimations indicate that the Tullock Formation in Eastern Montana was deposited over a time span of ~ 1000 kyr subsequent to the Cretaceous - Paleogene boundary, dated at ~ 65.95 Ma [1]. Initial high-resolution magnetostratigraphy revealed the occurrence of the C29r/C29n polarity reversal which was stratigraphic consistent at different field locations. We investigate the regional significance of sedimentary change at multiple sites of the same age in order to provide improved insight on the role of orbital forcing in fluvial coal formation. References: [1] Kuiper, K.F., Deino, A., Hilgen, F.J., Krijgsman, W., Renne, P.R., Wijbrans, J.R. (2008). Synchronizing Rock Clocks of Earth History. Science 320, 500-504.

Aeroacoustics of contoured and solid/porous conical plug-nozzle supersonic jet flows

NASA Technical Reports Server (NTRS)

Dosanjh, D. S.; Das, I. S.

1985-01-01

The acoustic far field, the shock-associated noise and characteristics of the repetitive shock structure of supersonic jet flows issuing from a contoured plug-nozzle and uncontoured plug-nozzle having a short conical plug of either a solid or a combination of solid/porous surface with pointed termination operated at a range of supercritical pressure are reported. The contoured and the uncontoured plug-nozzles had the same throat area and the same annular-radius ratio.

An objective comparison of leakage between commonly used earplugs.

PubMed

Alt, Jeremiah A; Collins, William O

2012-01-01

We sought to determine the efficacy of commonly used earplugs using an anatomically correct ear model. The total volume and rate of water that leaked past the earplug and subsequent defect in the tympanic membrane over separately measured 30, 60, 120, and 180-second intervals were recorded. Scenarios tested included a control with no earplug, custom molded earplug (Precision Laboratories, Orlando, FL), Mack's plug (Warren, MI), Doc's plug (Santa Cruz, CA), and cotton balls coated with petroleum jelly. All plugs tested resulted in less leakage at all time points when compared with no plug (P < .05). At 30 seconds, the custom molded, Mack's and Doc's plugs all showed significantly less leakage when compared with the cotton ball coated with petroleum jelly (P < .05). At 60, 120, and 180 seconds, Mack's, Doc's, and the cotton plugs all showed significantly less leakage compared with the customized plug (P < .05). At 120 and 180 seconds, Mack's plugs had significant less leakage than the cotton plug (P < .05). Among the types of plugs, the molded variety (Mack's) showed the least volume and lowest leakage rate (f(4,45) = 94 [P < .001]). In addition, Doc's and cotton balls coated with petroleum jelly were more effective than the customized earplugs. If the clinician feels that middle ear and external canal water exposure should be minimized, then use of earplugs, particularly the moldable variety, merits further consideration. Copyright © 2012 Elsevier Inc. All rights reserved.

Volcanism and massive sulfide formation at a sedimented spreading center, Escanaba Trough, Gorda Ridge, northeast Pacific.

USGS Publications Warehouse

Morton, J.L.; Holmes, M.L.; Koski, R.A.

1987-01-01

Seismic-reflection profiles over the sediment-filled Escanaba Trough at the southern Gorda Ridge reveal a series of volcanic centers that pierce the sediment. The volcanic edifices are 3 to 6 km in diameter and are spaced at 15 to 20 km intervals along the axis of the trough. Composition and form of sulfide samples obtained from the bank suggest significant interaction between hydrothermal fluids and sediment at depth, and deposition of sulfide within the sediment pile.-from Authors

Data for ground-water test hole near Butte City, Central Valley aquifer project, California

USGS Publications Warehouse

French, James J.; Page, R.W.; Bertoldi, G.L.

1983-01-01

This report provides preliminary data for the third of seven test holes drilled as part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 NE 1/4 sec. 32, T. 19 N., R. 1 W., Glenn County, California, about one-half mile south of the town of Butte City. Drilled to a depth of 1,432 feet below land surface, the hole is cased to a depth of 82 feet and equipped with three piezometer tubes to depths of 592 feet, 968 feet, and 1,330 feet. A 5-foot well screen is at the bottom of each piezometer. Each screened interval has a cement plug above and below it to isolate it from other parts of the aquifer , and the well bore is filled between the plugs with sediment. Nine cores and 49 sidewall cores were recovered. Laboratory tests were made for mineralogy, hydraulic conductivity, porosity , consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, and chemical quality of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis and measured for water level in the three tapped zones. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

Data for ground-water test hole near Nicolaus, Central Valley aquifer project, California

USGS Publications Warehouse

French, James J.; Page, R.W.; Bertoldi, Gilbert L.

1983-01-01

Preliminary data are provided for the third of seven test holes drilled as a part of the Central Valley Aquifer Project which is part of the National Regional Aquifer Systems Analysis Program. The test hole was drilled in the SW 1/4 NE 1/4 sec. 2, T.12N., R.3E., Sutter County, California, about 1 1/2 miles northwest of the town of Nicolaus. Drilled to a depth of 1,150 feet below land surface, the hole is cased to a depth of 100 feet and equipped with three piezometer tubes to depths of 311, 711, and 1,071 feet. A 5-foot well screen is set in sand at the bottom of each piezometer. Each screened interval has a cement plug above and below it to isolate it from other parts of the aquifer, and the well bore is filled between the plugs with sediment. Thirty-one cores and 34 sidewall cores were recovered. Laboratory tests were made for minerology, consolidation, grain-size distribution, Atterberg limits, X-ray diffraction, thermal conductivity, and chemical analysis of water. Geophysical and thermal gradient logs were made. The hole is sampled periodically for chemical analysis of the three tapped zones and measured for water level. This report presents methods used to obtain field samples, laboratory procedures, and the data obtained. (USGS)

Low-maturity Kulthieth Formation coal: A possible source of polycyclic aromatic hydrocarbons in benthic sediment of the northern Gulf of Alaska

USGS Publications Warehouse

Van Kooten, G. K.; Short, J.W.; Kolak, J.J.

2002-01-01

The successful application of forensic geology to contamination studies involving natural systems requires identification of appropriate endmembers and an understanding of the geologic setting and processes affecting the systems. Studies attempting to delineate the background, or natural, source for hydrocarbon contamination in Gulf of Alaska (GOA) benthic sediments have invoked a number of potential sources, including seep oils, source rocks, and coal. Oil seeps have subsequently been questioned as significant sources of hydrocarbons present in benthic sediments of the GOA in part because the pattern of relative polycyclic aromatic hydrocarbon (PAH) abundance characteristic of benthic GOA sediments is inconsistent with patterns typical of weathered seep oils. Likewise, native coal has been dismissed in part because ratios of labile hydrocarbons to total organic carbon (e.g. PAH:TOC) for Bering River coal field (BRCF) sources are too low - i.e. the coals are over mature - to be consistent with GOA sediments. We present evidence here that native coal may have been prematurely dismissed, because BRCF coals do not adequately represent the geochemical signatures of coals elsewhere in the Kulthieth Formation. Contrary to previous thought, Kulthieth Formation coals east of the BRCF have much higher PAH: TOC ratios, and the patterns of labile hydrocarbons in these low thermal maturity coals suggest a possible genetic relationship between Kulthieth Formation coals and nearby oil seeps on the Sullivan anticline. Analyses of low-maturity Kulthieth Formation coal indicate the low maturity coal is a significant source of PAH. Source apportionment models that neglect this source will underestimate the contribution of native coals to the regional background hydrocarbon signature. ?? Published by Elsevier Science Ltd. on behalf of AEHS.

Manganese carbonates in the Upper Jurassic Georgiev Formation of the Western Siberian marine basin

NASA Astrophysics Data System (ADS)

Eder, Vika G.; Föllmi, Karl B.; Zanin, Yuri N.; Zamirailova, Albina G.

2018-01-01

Manganese (Mn) carbonate rocks are a common lithological constituent of the Upper Oxfordian to Lower Tithonian (Volgian) Georgiev Formation of the Western Siberian marine basin (WSMB). The Mn carbonates in the Georgiev Formation are present in the form of massive sediments, stromatolites, and oncolites, and are associated with glauconite and partly also phosphate-rich clay- and siltstones. Unlike most Mn carbonates, they are not directly associated with organic-rich sediments, but occur below an organic-rich succession (Bazhenov Formation). The Mn carbonate occurrences can be traced from the western central area of the WSMB to its center along a distance of at least 750 km. The thickness of the Mn carbonates and their Mn contents becomes reduced in an eastward direction, related to increased detrital input. The geochemical and mineralogical heterogeneity within the Mn carbonates indicates that they were deposited stepwise in a diagenetic regime characterized by steep gradients in Mn, Ca, and Mg. A first step consisted in the replacement of initial sediments within the microbialites during an early diagenetic stage, followed by a second step where massive sediments were transformed into Mn carbonate. During both steps, the decomposition of organic matter was an important source of the newly formed carbonate. During a further step, voids were cemented by Mn carbonates, which are rich in pyrite. This last generation may only have formed once the organic-rich sediments of the overlying Bazhenov Formation were deposited. Accumulation of the Mn carbonates in the Upper Jurassic WSMB was controlled by the proximity of Mn-enriched parent rocks, likely in the Ural, which were subjected to intense geochemical weathering during the Late Jurassic.

Sediment composition and texture of Pleistocene deep-sea turbidites in the eastern Nankai Trough gas hydrate field

NASA Astrophysics Data System (ADS)

Egawa, K.; Nishimura, O.; Izumi, S.; Ito, T.; Konno, Y.; Yoneda, J.; Jin, Y.; Kida, M.; Suzuki, K.; Nakatsuka, Y.; Nagao, J.

2013-12-01

In the 2012 JOGMEC/JAPEX pressure coring operation, we collected a totally 60-m-long core sample from the interval of gas hydrate concentration zone at the planned site of the world's first offshore production test of natural gas hydrates in the eastern Nankai Trough area. In this contribution, the cored sediments were sedimentologically, mineralogically, and paleontologically analyzed to know sediment composition and texture of reservoir formation, which are known to provide useful geological information to discuss sedimentation, diagenesis, and permeability. The targeted interval belongs to a Middle Pleistocene deep-sea turbidite sequence distributed around the Daini Atsumi Knoll, east of the Kumano forearc basin, and consists of the lower (thick sand-dominant), middle (thin-bedded sand-and-mud alteration), and upper (mud-dominant) formations in ascending order. X-ray powder diffraction analysis and scanning electron microscopic observation revealed that pore space in turbidite sands is commonly filled with clay fractions (mostly phyllosilicates) in the lower formation. Such a pore filling of clay fractions is reflected in particle size distribution showing high standard deviation and clay content, and thus is expected to have an impact on permeability. There is the older Pliocene to Early Pleistocene fossil coccolith record in the middle formation, indicating sediment reworking probably induced by submarine landslide. The coexistence of authigenic siderite and framboidal pyrite in the middle formation strongly suggests anoxic microbial activity under methane oxidation and sulfide reduction conditions at least before the hydrate cementation. This contribution was financially supported by the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) planned by the Ministry of Economy, Trade and Industry (METI).

Electrostatic networks control plug stabilization in the PapC usher.

PubMed

Pham, Thieng; Henderson, Nadine S; Werneburg, Glenn T; Thanassi, David G; Delcour, Anne H

2015-01-01

The PapC usher, a β-barrel pore in the outer membrane of uropathogenic Escherichia coli, is used for assembly of the P pilus, a key virulence factor in bacterial colonization of human kidney cells. Each PapC protein is composed of a 24-stranded β-barrel channel, flanked by N- and C-terminal globular domains protruding into the periplasm, and occluded by a plug domain (PD). The PD is displaced from the channel towards the periplasm during pilus biogenesis, but the molecular mechanism for PD displacement remains unclear. Two structural features within the β-barrel, an α-helix and β5-6 hairpin loop, may play roles in controlling plug stabilization. Here we have tested clusters of residues at the interface of the plug, barrel, α-helix and hairpin, which participate in electrostatic networks. To assess the roles of these residues in plug stabilization, we used patch-clamp electrophysiology to compare the activity of wild-type and mutant PapC channels containing alanine substitutions at these sites. Mutations interrupting each of two salt bridge networks were relatively ineffective in disrupting plug stabilization. However, mutation of two pairs of arginines located at the inner and the outer surfaces of the PD resulted in an enhanced propensity for plug displacement. One arginine pair involved in a repulsive interaction between the linkers that tether the plug to the β-barrel was particularly sensitive to mutation. These results suggest that plug displacement, which is necessary for pilus assembly and translocation, may require a weakening of key electrostatic interactions between the plug linkers, and the plug and the α-helix.

Production of arrays of chemically distinct nanolitre plugs via repeated splitting in microfluidic devices.

PubMed

Adamson, David N; Mustafi, Debarshi; Zhang, John X J; Zheng, Bo; Ismagilov, Rustem F

2006-09-01

This paper reports a method for the production of arrays of nanolitre plugs with distinct chemical compositions. One of the primary constraints on the use of plug-based microfluidics for large scale biological screening is the difficulty of fabricating arrays of chemically distinct plugs on the nanolitre scale. Here, using microfluidic devices with several T-junctions linked in series, a single input array of large (approximately 320 nL) plugs was split to produce 16 output arrays of smaller (approximately 20 nL) plugs; the composition and configuration of these arrays were identical to that of the input. This paper shows how the passive break-up of plugs in T-junction microchannel geometries can be used to produce a set of smaller-volume output arrays useful for chemical screening from a single large-volume array. A simple theoretical description is presented to describe splitting as a function of the Capillary number, the capillary pressure, the total pressure difference across the channel, and the geometric fluidic resistance. By accounting for these considerations, plug coalescence and plug-plug contamination can be eliminated from the splitting process and the symmetry of splitting can be preserved. Furthermore, single-outlet splitting devices were implemented with both valve- and volume-based methods for coordinating the release of output arrays. Arrays of plugs containing commercial sparse matrix screens were obtained from the presented splitting method and these arrays were used in protein crystallization trials. The techniques presented in this paper may facilitate the implementation of high-throughput chemical and biological screening.

The Sedimentary History of Southern Central Crete: Implications for Neogene Uplift

NASA Astrophysics Data System (ADS)

Kröger, K.; Brachert, T. C.; Reuter, M.

2003-04-01

The tectonic setting of Crete was largely extensional since Lower Miocene uplift and exhumation of HP/LT rocks. Erosion of uplifted areas resulted in the deposition of terrestrial to marine sediments in the Messara and Iraclion Basins. There are several concurring models that discuss Late Neogene uplift of the basinal margins. Neogene near shore sediments in the south of the Messara Basin record fault movements contemporaneous to sedimentation and sedimentary input from the hinterland. Therefore they provide information on the paleogeographic situation and the resulting amount of subsidence and uplift of mountain areas since the Upper Miocene. The studied sediments consist of terrestrial to shallow marine, floodplain related sediments of the Upper Miocene Ambelouzos Formation that are overlain by platform limestones of the Upper Miocene Varvara Formation. In the Messara Basin these units are overlain by the Pliocene Kourtes Formation. The stratigraphic architecture of these deposits indicates fragmentation of the basinal margin. Proximal boulder conglomerates and reworked blocks of the Ambelouzos formation indicate fault activity during the deposition of the Varvara Formation. Contents of terrigenous clastics, provided by rivers and distributed by longshore currents, are high in the Ambelouzos and the lower Varvara Formations but decrease rapidly upsection within the Varvara Formation. This indicates drowning of the fault bounded blocks and little topography of the hinterland (Asteroussia Mountains) at that time. The Pliocene marls at the southern margin of the Messara Basin contain lithoclasts of the Upper Miocene limestones and thus indicate uplift of the carbonate platform. The modern topographic elevation of formerly drowned fault bounded blocks requires a minimum uplift of 400m. Main uplift occurred at approximately orthogonal NW-SE and SW-NE striking normal to oblique faults. The present elevation of the Asteroussia Mountains indicates net uplift of at least 1000m since the Early Pliocene. At the Central Iraklion Ridge that separates the Messara and Iraclion Basins a similar history is indicated for the Psiloritis Mountains by fault movements within Neogene near shore sediments and their subsequent drowning. A structural model of the Neogene evolution of Crete therefore has to explain successive phases of uplift and subsidence in an over all extensional setting only slightly oblique to the modern direction of convergence between Africa and the Aegean microplate.

Alternative Fuels Data Center: Developing Infrastructure to Charge Plug-In

Science.gov Websites

Electric Vehicles Developing Infrastructure to Charge Plug-In Electric Vehicles to someone by E -mail Share Alternative Fuels Data Center: Developing Infrastructure to Charge Plug-In Electric Vehicles on Facebook Tweet about Alternative Fuels Data Center: Developing Infrastructure to Charge Plug-In

40 CFR 146.92 - Injection well plugging.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Injection well plugging. 146.92... to Class VI Wells § 146.92 Injection well plugging. (a) Prior to the well plugging, the owner or operator must flush each Class VI injection well with a buffer fluid, determine bottomhole reservoir...

40 CFR 144.62 - Cost estimate for plugging and abandonment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... must revise the plugging and abandonment cost estimate whenever a change in the plugging and... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Cost estimate for plugging and abandonment. 144.62 Section 144.62 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER...

Gum and deposit formation in diesel fuels. Final report, 1984-1988

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

Mayo, F.R.; Mill, T.

1988-05-15

The authors examined two aspects of the stability of diesel fuels in storage: the formation of sediments in suspension, which subsequently clog filters, and the formation of soluble gum, which passes the filters but then forms hard deposits on hot engine parts. Research on fuel stability at SRI during the last 6 years has shown that soluble gum appears first on storage, and then part of it grows into sediment. If the oxidation mixture is agitated gently, the precipitating gum grows on the surface gum, and no loose sediment is formed. Three mechanisms of gum formation were distinguished: (1) amore » process intimately associated with chain propagation and termination during oxidation, (2) a coupling of fuel molecules by decomposing peroxides in the absence of oxygen, and (3) a condensation of naphthols and aldehydes from the oxidation of alkylnaphthalenes. The polymeric oxidation products from a JP-8 fuel are shown to be largely responsible for deposits in the Jet Fuel Thermal Oxidation Tester (JFTOT).« less

Fiber optic sensing technology for detecting gas hydrate formation and decomposition.

PubMed

Rawn, C J; Leeman, J R; Ulrich, S M; Alford, J E; Phelps, T J; Madden, M E

2011-02-01

A fiber optic-based distributed sensing system (DSS) has been integrated with a large volume (72 l) pressure vessel providing high spatial resolution, time-resolved, 3D measurement of hybrid temperature-strain (TS) values within experimental sediment-gas hydrate systems. Areas of gas hydrate formation (exothermic) and decomposition (endothermic) can be characterized through this proxy by time series analysis of discrete data points collected along the length of optical fibers placed within a sediment system. Data are visualized as an animation of TS values along the length of each fiber over time. Experiments conducted in the Seafloor Process Simulator at Oak Ridge National Laboratory clearly indicate hydrate formation and dissociation events at expected pressure-temperature conditions given the thermodynamics of the CH(4)-H(2)O system. The high spatial resolution achieved with fiber optic technology makes the DSS a useful tool for visualizing time-resolved formation and dissociation of gas hydrates in large-scale sediment experiments.

Fiber optic sensing technology for detecting gas hydrate formation and decomposition

NASA Astrophysics Data System (ADS)

Rawn, C. J.; Leeman, J. R.; Ulrich, S. M.; Alford, J. E.; Phelps, T. J.; Madden, M. E.

2011-02-01

A fiber optic-based distributed sensing system (DSS) has been integrated with a large volume (72 l) pressure vessel providing high spatial resolution, time-resolved, 3D measurement of hybrid temperature-strain (TS) values within experimental sediment-gas hydrate systems. Areas of gas hydrate formation (exothermic) and decomposition (endothermic) can be characterized through this proxy by time series analysis of discrete data points collected along the length of optical fibers placed within a sediment system. Data are visualized as an animation of TS values along the length of each fiber over time. Experiments conducted in the Seafloor Process Simulator at Oak Ridge National Laboratory clearly indicate hydrate formation and dissociation events at expected pressure-temperature conditions given the thermodynamics of the CH4-H2O system. The high spatial resolution achieved with fiber optic technology makes the DSS a useful tool for visualizing time-resolved formation and dissociation of gas hydrates in large-scale sediment experiments.

Geochemistry of Permian rocks from the margins of the Phosphoria Basin

USGS Publications Warehouse

Perkins, Robert B.; McIntyre, Brandie; Hein, James R.; Piper, David Z.

2003-01-01

The Permian Phosphoria Formation and interbedded units of the Park City Formation and Shedhorn Sandstone in western Wyoming represent deposition along a carbonate ramp at the eastern margin of the Phosphoria Basin, with portions of the Phosphoria units reflecting periods of upwelling and widespread phosphogenesis. Thickness-weighted slab-samples of these units were collected at a maximum interval of 3 m along an 80+ m-length of unweathered core and analyzed for major-, minor-, and trace-element contents. Interpretations of geochemistry were made within the confines of a previously recognized sequence stratigraphy framework. Major shifts in element ratios characteristic of terrigenous debris that occur at sequence boundaries at the base of the Meade Peak and Retort Members of the Phosphoria Formation are attributed to changing sediment sources. Inter-element relationships in the marine fraction indicate that bottom waters of the Phosphoria Basin were predominantly denitrifying during deposition of the Ervay, Grandeur, and Phosphoria sediments, although sulfate-reducing conditions may have existed during deposition of the lower Meade Peak sediments. Oxic conditions were prevalent during deposition of a large part of the Franson Member, which represents sedimentation in a shallow, inner- to back-ramp setting. Variations in sediment facies and organic matter and trace element contents largely reflect changes in Permian sea level. Changes in sea level in basin-margin areas, such as represented by the study section, may have affected the oxidation of settling organic matter, the foci of intersection of upwelling bottom waters with the photic zone, the rate of terrigenous sedimentation, and, ultimately, the overall environment of deposition. Our study suggests that phosphogenesis can occur under lowstand, transgressive, and highstand conditions in marginal areas, assuming water depths sufficient for upwelling to occur. Formation of phosphorite layers under upwelling conditions appears to have been most dependent on a lack of dilution by terrigenous sedimentation and carbonate shoaling. Differences in the geochemistry between two similar environments represented by the upper and lower Phosphoria units are largely attributed to higher rates of diluting terrigenous sediment during deposition of the upper unit. This is consistent with prior interpretations of a more shoreward setting for the upper Phosphoria.

A combined Eulerian-Lagrangian two-phase flow analysis of SSME HPOTP nozzle plug trajectories. II - Results

NASA Technical Reports Server (NTRS)

Mcconnaughey, P. K.; Garcia, R.; Dejong, F. J.; Sabnis, J. S.; Pribik, D. A.

1989-01-01

An analysis of Space Shuttle Main Engine high-pressure oxygen turbopump nozzle plug trajectories has been performed, using a Lagrangian method to track nozzle plug particles expelled from a turbine through a high Reynolds number flow in a turnaround duct with turning vanes. Axisymmetric and parametric analyses reveal that if nozzle plugs exited the turbine they would probably impact the LOX heat exchanger with impact velocities which are significantly less than the penetration velocity. The finding that only slight to moderate damage will result from nozzle plug failure in flight is supported by the results of a hot-fire engine test with induced nozzle plug failures.

Kinetics and mechanisms of iron sulfide reductions in hydrogen and in carbon monoxide

USGS Publications Warehouse

Wiltowski, T.; Hinckley, C.C.; Smith, Gerard V.; Nishizawa, T.; Saporoschenko, Mykola; Shiley, R.H.; Webster, J.R.

1987-01-01

The reduction of iron sulfides by hydrogen and by carbon monoxide has been studied using plug flow and thermogravimetric methods. The reactions were studied in the 523-723??K temperature range and were found to be first-order processes. Plug flow studies were used to correlate reaction rates between pyrite and the gases as a function of the surface area of the pyrite. The rate of H2S formation increases with the surface area of the pyrite sample. The results of thermogravimetric experiments indicate that the reactions consist of several steps. Rate constants for the pyrite reduction by H2 and by CO were obtained. The activation energies increased with degree of reduction. Values of Ea were 113.2 (step I) and 122.5 kJ/mole (step II) for pyrite reduction with CO and 99.4 (step I), 122.4 (step II), 125.2 (step III), and 142.6 kJ/mole (step IV) for pyrite reduction with hydrogen. ?? 1987.

The plug-based nanovolume Microcapillary Protein Crystallization System (MPCS)

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

Gerdts, Cory J.; Elliott, Mark; Lovell, Scott

2012-02-08

The Microcapillary Protein Crystallization System (MPCS) embodies a new semi-automated plug-based crystallization technology which enables nanolitre-volume screening of crystallization conditions in a plasticware format that allows crystals to be easily removed for traditional cryoprotection and X-ray diffraction data collection. Protein crystals grown in these plastic devices can be directly subjected to in situ X-ray diffraction studies. The MPCS integrates the formulation of crystallization cocktails with the preparation of the crystallization experiments. Within microfluidic Teflon tubing or the microfluidic circuitry of a plastic CrystalCard, {approx}10-20 nl volume droplets are generated, each representing a microbatch-style crystallization experiment with a different chemical composition.more » The entire protein sample is utilized in crystallization experiments. Sparse-matrix screening and chemical gradient screening can be combined in one comprehensive 'hybrid' crystallization trial. The technology lends itself well to optimization by high-granularity gradient screening using optimization reagents such as precipitation agents, ligands or cryoprotectants.« less

Ferrimagnetic Iron Sulfide Formation and Methane Venting Across the Paleocene-Eocene Thermal Maximum in Shallow Marine Sediments, Ancient West Siberian Sea

NASA Astrophysics Data System (ADS)

Rudmin, Maxim; Roberts, Andrew P.; Horng, Chorng-Shern; Mazurov, Aleksey; Savinova, Olesya; Ruban, Aleksey; Kashapov, Roman; Veklich, Maxim

2018-01-01

Authigenesis of ferrimagnetic iron sulfide minerals (greigite and monoclinic pyrrhotite) occurred across the Paleocene-Eocene Thermal Maximum (PETM) within the Bakchar oolitic ironstone in southeastern Western Siberia. Co-occurrence of these minerals is associated with diagenetic environments that support anaerobic oxidation of methane, which has been validated by methane fluid inclusion analysis in the studied sediments. In modern settings, such ferrimagnetic iron sulfide formation is linked to upward methane diffusion in the presence of minor dissolved sulfide ions. The PETM was the most extreme Cenozoic global warming event and massive methane mobilization has been proposed as a major contributor to the globally observed warming and carbon isotope excursion associated with the PETM. The studied sediments provide rare direct evidence for methane mobilization during the PETM. Magnetic iron sulfide formation associated with methanogenesis in the studied sediments can be explained by enhanced local carbon burial across the PETM. While there is no strong evidence to link local methane venting with more widespread methane mobilization and global warming, the magnetic, petrographic, and geochemical approach used here is applicable to identifying authigenic minerals that provide telltale signatures of methane mobility that can be used to assess methane formation and mobilization through the PETM and other hyperthermal climatic events.

Neotectonic Activity from Karewa Sediments, Kashmir Himalaya, India

NASA Astrophysics Data System (ADS)

Agarwal, K. K.; Shah, R. A.; Achyuthan, H.; Singh, D. S.; Srivastava, S.; Khan, I.

2018-01-01

Intermontane basin sedimentation occurred during Pliocene-Pleistocene in the Karewa Basin which formed after the continent-continent collision resulting in the formation of Himalayan orogenic belt around Eocene. These are elongated, narrow, thrust bounded basins which have formed during the late stages of orogeny. Situated at a height of 1700-1800 m above sea level, the Karewa basin received sediments because of ponding of a pre-existing river system and the tectonic movements along the Great Himalayan Ranges in the north and the Pir-Panjal ranges in the south along active faults. About 1300 m thick sediments of largely fluvio-lacustrine, glacio-fluvio-lacustrine and eolian origin are exposed having evidences of neotectonically formed structural features such as folds and faults. Folds are more prominent in the Lower Karewa formation (Hirpur Formation) while faults (mostly normal faults) are abundant in the Upper Karewas (Nagum Formation). Drainage in the area varies from dendritic to anastomosing to parallel. Anastomosing drainage suggests sudden decrease in gradient while presence of linear features such as faults and ridges is evident by parallel drainage. Study of morphometric parameters such as stream length (Lsm) and stream length ratios (RL), bifurcation ratio (Rb), drainage density (D), form factor (Rf), circularity ratio (Rc), and elongation ratio (Re) also indicate intense tectonic activity in the recent past.

Burner rig study of variables involved in hole plugging of air cooled turbine engine vanes

NASA Technical Reports Server (NTRS)

Deadmore, D. L.; Lowell, C. E.

1983-01-01

The effects of combustion gas composition, flame temperatures, and cooling air mass flow on the plugging of film cooling holes by a Ca-Fe-P-containing deposit were investigated. The testing was performed on film-cooled vanes exposed to the combustion gases of an atmospheric Mach 0.3 burner rig. The extent of plugging was determined by measurement of the open hole area at the conclusion of the tests as well as continuous monitoring of some of the tests using stop-action photography. In general, as the P content increased, plugging rates also increased. The plugging was reduced by increasing flame temperature and cooling air mass flow rates. At times up to approximately 2 hours little plugging was observed. This apparent incubation period was followed by rapid plugging, reaching in several hours a maximum closure whose value depended on the conditions of the test.

Playing with Plug-ins

ERIC Educational Resources Information Center

Thompson, Douglas E.

2013-01-01

In today's complex music software packages, many features can remain unexplored and unused. Software plug-ins--available in most every music software package, yet easily overlooked in the software's basic operations--are one such feature. In this article, I introduce readers to plug-ins and offer tips for purchasing plug-ins I have…

40 CFR 144.62 - Cost estimate for plugging and abandonment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Cost estimate for plugging and... Waste Injection Wells § 144.62 Cost estimate for plugging and abandonment. (a) The owner or operator must prepare a written estimate, in current dollars, of the cost of plugging the injection well in...

Steady propagation of Bingham plugs in 2D channels

NASA Astrophysics Data System (ADS)

Zamankhan, Parsa; Takayama, Shuichi; Grotberg, James

2009-11-01

The displacement of the yield-stress liquid plugs in channels and tubes occur in many biological systems and industrial processes. Among them is the propagation of mucus plugs in the respiratory tracts as may occur in asthma, cystic fibrosis, or emphysema. In this work the steady propagation of mucus plugs in a 2D channel is studied numerically, assuming that the mucus is a pure Bingham fluid. The governing equations are solved by a mixed-discontinuous finite element formulation and the free surface is resolved with the method of spines. The constitutive equation for a pure Bingham fluid is modeled by a regularization method. Fluid inertia is neglected, so the controlling parameters in a steady displacement are; the capillary number, Ca, Bingham number ,Bn, and the plug length. According to the numerical results, the yield stress behavior of the plug modifies the plug shape, the pattern of the streamlines and the distribution of stresses in the plug domain and along the walls in a significant way. The distribution along the walls is a major factor in studying cell injuries. This work is supported through the grant NIH HL84370.

Five 'Supercool' Icelandic Glaciers

NASA Astrophysics Data System (ADS)

Knudsen, O.; Roberts, M. J.; Roberts, M. J.; Tweed, F. S.; Russell, A. J.; Lawson, D. E.; Larson, G. J.; Evenson, E. B.; Bjornsson, H.

2001-12-01

Sediment entrainment by glaciohydraulic supercooling has recently been demonstrated as an effective process at Matanuska glacier, Alaska. Although subfreezing meltwater temperatures have been recorded at several Alaskan glaciers, the link between supercooling and sediment accretion remains confined to Matanuska. This study presents evidence of glaciohydraulic supercooling and associated basal ice formation from five Icelandic glaciers: Skeidarárjökull, Skaftafellsjökull, Kvíárjökull, Flaájökull, and Hoffellsjökull. These observations provide the best example to-date of glaciohydraulic supercooling and related sediment accretion outside Alaska. Fieldwork undertaken in March, July and August 2001 confirmed that giant terraces of frazil ice, diagnostic of the presence of supercooled water, are forming around subglacial artesian vents. Frazil flocs retrieved from these vents contained localised sandy nodules at ice crystal boundaries. During periods of high discharge, sediment-laden frazil flocs adhere to the inner walls of vents, and continue to trap suspended sediment. Bands of debris-rich frazil ice, representing former vents, are texturally similar to basal ice exposures at the glacier margins, implying a process-form relationship between glaciohydraulic freeze-on and basal ice formation. It is hypothesised that glaciohydraulic supercooling is generating thick sequences of basal ice. Observations also confirm that in situ melting of basal ice creates thick sedimentary sequences, as sediment structures present in the basal ice can be clearly traced into ice-marginal ridges. Glaciohydraulic supercooling is an effective sediment entrainment mechanism at Icelandic glaciers. Supercooling has the capacity to generate thick sequences of basal ice and the sediments present in basal ice can be preserved. These findings are incompatible with established theories of intraglacial sediment entrainment and basal ice formation; instead, they concur with, and extend, the current model of Matanuska-type glaciohydraulic supercooling. This work adds a new dimension to the understanding of debris entrainment in temperate glaciers.

Modeling the formation of methane hydrate-bearing intervals in fine-grained sediments

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

Malinverno, Alberto; Cook, Ann; Daigle, Hugh

Sediment grain size exerts a fundamental control on how methane hydrates are distributed within the pore space. Fine-grained muds are the predominant sediments in continental margins, and hydrates in these sediments have often been observed in semi-vertical veins and fractures. In several instances, these hydrate veins/fractures are found in discrete depth intervals a few tens meters thick within the gas hydrate stability zone (GHSZ) surrounded by hydrate-free sediments above and below. As they are not obviously connected with free gas occurring beneath the base of the GHSZ, these isolated hydrate-bearing intervals have been interpreted as formed by microbial methane generatedmore » in situ. To investigate further the formation of these hydrate deposits, we applied a time-dependent advection-diffusion-reaction model that includes the effects of sedimentation, solute diffusion, and microbial methane generation. The microbial methane generation term depends on the amount of metabolizable organic carbon deposited at the seafloor, which is degraded at a prescribed rate resulting in methane formation beneath the sulfate reduction zone. In the model, methane hydrate precipitates once the dissolved methane concentration is greater than solubility, or hydrate dissolves if concentration goes below solubility. If the deposition of organic carbon at the seafloor is kept constant in time, we found that the predicted amounts of hydrate formed in discrete intervals within the GHSZ are much less than those estimated from observations. We then investigated the effect of temporal variations in the deposition of organic carbon. If greater amounts of organic carbon are deposited during some time interval, methane generation is enhanced during burial in the corresponding sediment interval. With variations in organic carbon deposition that are consistent with observations in continental margin sediments, we were able to reproduce the methane hydrate contents estimated in discrete depth intervals. Our results support the suggestion that in situ microbial methane generation is the source for hydrates within fine-grained sediments.« less

Paired measurements of K and Mg isotopes and clay authigenesis in marine sediments

NASA Astrophysics Data System (ADS)

Santiago Ramos, D. P.; Dunlea, A. G.; Higgins, J. A.

2016-12-01

Despite its importance as a major sink for seawater K and Mg, estimates of clay authigenesis in marine sediments remain poorly constrained. Previous work on Mg isotope fractionation during clay formation has revealed a preferential uptake of 26Mg, yielding authigenic clay products with potentially distinct δ26Mg compared to the detrital component. In a similar manner, we aim to quantify the K isotope fractionation during authigenic clay formation and to use paired δ26Mg and δ41K measurements as proxies for the identification and quantification of authigenic clays in shallow and deep marine sedimentary systems. To better understand the behavior of paired Mg and K isotopes during authigenic clay formation in marine sediments, we measured δ26Mg and δ41K values of pore-fluids and sediments from ODP/IODP sites 1052, U1395, U1403 and U1366. We find that while pore-fluid K concentrations at sites 1052, U1395 and U1403 all decline with depth, δ41K profiles differ significantly. These differences might be a result of a complex interplay between clay authigenesis, sedimentation rate, and fractionation of K isotopes during diffusion. Results from 1-D diffusion-advection-reaction models suggest that, in contrast to Mg, diffusion may play an important role in determining the overall K isotope fractionation during clay authigenesis in sites with low-sedimentation rates. Sites with high sedimentation rates may act as close systems where diffusion is negligible. In such cases, K uptake can be modeled as a Rayleigh distillation process and K isotope fractionation can be estimated. Measurements of δ26Mg and δ41K of pore-fluids from site U1395 and bulk sediments from U1366 suggest that paired measurements of these isotopic systems in siliciclastic marine sediments can provide new insights into rates of marine clay authigenesis, a globally important but understudied component of many geochemical cycles.

Portal vein embolization with plug/coils improves hepatectomy outcome.

PubMed

Malinowski, Maciej; Geisel, Dominik; Stary, Victoria; Denecke, Timm; Seehofer, Daniel; Jara, Maximillian; Baron, Annekathrin; Pratschke, Johann; Gebauer, Bernhard; Stockmann, Martin

2015-03-01

Portal vein embolization (PVE) has become the standard of care before extended hepatectomy. Various PVE methods using different embolization materials have been described. In this study, we compared PVE with polyvinyl alcohol particles alone (PVA only) versus PVA with plug or coils (PVA + plug/coils). Patients undergoing PVE before hepatectomy were included. PVA alone was used until December 2013, thereafter plug or coils were placed in addition. The volume of left lateral liver lobe (LLL), clinical parameters, and liver function tests were measured before PVE and resection. A total of 43 patients were recruited into the PVA only group and 42 were recruited into the PVA + plug/coils group. There were no major differences between groups except significantly higher total bilirubin level before PVE in the PVA only group, which improved before hepatectomy. Mean LLL volume increased by 25.7% after PVE in the PVA only group and by 44% in the PVA + plug/coils group (P < 0.001). Recanalization was significantly less common in the PVA + plug/coils group. In multivariate regression, initial LLL volume and use of plug or coils were the only parameters influencing LLL volume increase. The postoperative liver failure rate was significantly reduced in PVA + plug/coils group (P = <0.001). PVE using PVA particles together with plug or coils is a safe and efficient method to increase future liver remnant volume. The additional central embolization with plug or coils led to an increased hypertrophy, due to lower recanalization rates, and subsequently decreased incidence of postoperative liver failure. No additional procedure-specific complications were observed in this series. Copyright © 2015 Elsevier Inc. All rights reserved.

Spaced planar laminations formed by repetitive basal erosion and resurgence to high-sedimentation-rate regime: new insight from a bedform-like structures and laterally continuous exposures

NASA Astrophysics Data System (ADS)

Ishihara, Yoshiro; Yuri, Onishi; Tsuda, Keisuke; Yokokawa, Miwa

2017-04-01

Spaced planar laminations (SPL), or so-called traction carpet deposits, are frequently observed in deposits of sediment gravity flows. Several sedimentation models for a succession of inversely graded units have been suggested from field observations and flume experiments. The formation of the inversely graded unit could be summarized as follows: (1) abrupt sedimentation on freezing of an inversely graded layer, or (2) interruptions in flow causing a freezing of an inversely graded layer at the most basal part of flow. In either case, traction carpets as a bed load overlying the erosive boundary at the base of flow are required. Although some descriptions have reported SPLs forming antidune bedform-like structures and the association of SPLs with structureless massive deposits have not been clearly explained. In this study, we suggest a novel model of SPL formation by repetition of basal erosion and resurgence to high-sedimentation rates, based on detail examinations of SPLs both showing bedform-like structures and lateral extents of hundreds of meters. SPLs were investigated in the Mio-Pliocene Kiyosumi Formation in central Japan and the Miocene Aoshima Formation in southwest Japan. In a turbidite in the Kiyosumi Formation, SPLs show three mound-like structures, suggesting antidune bedforms with wavelengths of about 6 to 7 m. On the upcurrent flanks, SPLs show lenticular cross laminations or pinching out of units; those units do not show clear inverse grading. Rip-up mud clasts and relatively high-angle imbrications are also observed. On the other hand, SPLs on the downcurrent flanks show relatively clear inverse grading and transition downcurrent into a massive structureless bed. In the Aoshima Formation, SPLs with ca. 1 cm unit thickness continue approximately 50 m along a palaeocurrent direction without changes in thickness. These SPLs gradually transition upward into a massive structureless unit. From the observations described above, in addition to descriptions from previous studies, it is suggested that SPLs comprising mound-like bedforms exhibit erosive conditions in the upcurrent flanks and depositional conditions in the downcurrent flanks, whereas SPLs on flat sea-floor extensively maintain their structure. Also, massive structureless beds are observed when erosion did not occur. These facts indicate that SPLs are strongly associated with an erosional process at the base of sediment gravity flows under a supercritical flow condition. The formation of SPLs does not necessary require a traction carpet and they may reflect basal erosion with a lag deposit of fine-grained particles, followed by resurgence to conditions of high sedimentation rates and massive structureless bed deposition. Repetitions of inversely graded units could occur when basal shear stresses are changed by fluctuations of flow depth, such as internal waves in a sediment gravity flow. This model can explain the concurrence of massive structureless beds with SPLs and examples of bedform-like structures without a unit thickness control.

Crevasse Splays Versus Avulsions: A Recipe for Land Building With Levee Breaches

NASA Astrophysics Data System (ADS)

Nienhuis, Jaap H.; Törnqvist, Torbjörn E.; Esposito, Christopher R.

2018-05-01

Natural-levee breaches can not only initiate an avulsion but also, under the right circumstances, lead to crevasse splay formation and overbank sedimentation. The formative conditions for crevasse splays are not well understood, yet such river sediment diversions form an integral part of billion-dollar coastal restoration projects. Here we use Delft3D to investigate the influence of vegetation and soil consolidation on the evolution of a natural-levee breach. Model simulations show that crevasse splays heal because floodplain aggradation reduces the water surface slope, decreasing water discharge into the flood basin. Easily erodible and unvegetated floodplains increase the likelihood for channel avulsions. Denser vegetation and less potential for soil consolidation result in small crevasse splays that are not only efficient sediment traps but also short-lived. Successful crevasse splays that generate the largest land area gain for the imported sediment require a delicate balance between water and sediment discharge, vegetation root strength, and soil consolidation.

Strength and acoustic properties of Ottawa sand containing laboratory-formed methane gas hydrate

USGS Publications Warehouse

Winters, William J.; Waite, William F.; Mason, David H.

2004-01-01

Although gas hydrate occurs in a wide variety of sediment types and is present and even pervasive at some locations on continental margins, little is known about how it forms naturally. Physical properties of the resultant gas hydrate-sediment mixtures, data needed for input into models that predict location and quantity of in situ hydrate are also lacking. Not only do properties of the host materials influence the type and quantity of hydrate formed and whether a particular deposit may be an economic resource or a geohazard, the properties of the natural sediment are also subsequently changed by the formation of gas hydrate in the pore space. The magnitude of the change is primarily related to the amount and the weighted inter-particle distribution of the hydrate deposits in relation to the actual sediment grains. Our goal is to understand the interaction between natural sediments and gas hydrate formation in order to quantify physical properties that are useful to predictive models.

Aquatic Plant Control Research Program. Effects of Organic Amendments to Sediment on Freshwater Macrophyte Growth.

DTIC Science & Technology

1983-10-01

Wiley and Sons, New York. Anderson, L. W. 1978. Abscisic acid induces formation of floating leaves in the heterophyllous aquatic angiosperm Potamogeton...the total sediment were determined following digestion in red-fuming nitric acid . Nutrients in sediment amendments and in macrophyte biomass were deter...inorganic matter. Organic matter content was 10% of dry sedi- ment mass. •* Sediment nutrient concentrations were determined following strong acidic

Physical properties of sediment containing methane gas hydrate

USGS Publications Warehouse

Winters, W.J.; Waite, W.F.; Mason, D.H.; Gilbert, L.Y.

2005-01-01

A study conducted by the US Geological Survey (USGS) on the formation, behavior, and properties of mixtures of gas hydrate and sediment is presented. The results show that the properties of host material influence the type and quantity of hydrates formed. The presence of hydrate during mechanical shear tests affects the measured sediment pore pressure. Sediment shear strength may be increased more than 500 percent by intact hydrate, but greatly weakened if the hydrate dissociates.

Structural characteristics of cohesive flow deposits, and a sedimentological approach on their flow mechanisms.

NASA Astrophysics Data System (ADS)

Tripsanas, E. K.; Bryant, W. R.; Prior, D. B.

2003-04-01

A large number of Jumbo Piston cores (up to 20 m long), acquired from the continental slope and rise of the Northwest Gulf of Mexico (Bryant Canyon area and eastern Sigsbee Escarpment), have recovered various mass-transport deposits. The main cause of slope instabilities over these areas is oversteepening of the slopes due to the seaward mobilization of the underlying allochthonous salt masses. Cohesive flow deposits were the most common recoveries in the sediment cores. Four types of cohesive flow deposits have been recognized: a) fluid debris flow, b) mud flow, c) mud-matrix dominated debris flow, and d) clast-dominated debris flow deposits. The first type is characterized by its relatively small thickness (less than 1 m), a mud matrix with small (less than 0.5 cm) and soft mud-clasts, and a faint layering. The mud-clasts reveal a normal grading and become more abundant towards the base of each layer. That reveals that their deposition resulted by several successive surges/pulses, developed in the main flow, than the sudden “freezing” of the whole flow. The main difference between mud flow and mud-matrix dominated debris flow deposits is the presence of small to large mud-clasts in the later. Both deposits consist of a chaotic mud-matrix, and a basal shear laminated zone, where the strongest shearing of the flow was exhibited. Convolute laminations, fault-like surfaces, thrust faults, and microfaults are interpreted as occurring during the “freezing” of the flows and/or by adjustments of the rested deposits. Clast-dominated debris flow deposits consist of three zones: a) an upper plug-zone, characterized by large interlocked clasts, b) a mid-zone, of higher reworked, inversely graded clasts, floating in a mud-matrix, and c) a lower shear laminated zone. The structure of the last three cohesive flow deposits indicate that they represent deposition of typical Bingham flows, consisting of an upper plug-zone in which the yield stress is not exceeded and an underlain shearing zone, where the shear stress exceeded the yield strength of the sediments. Mud-matrix, and clast-dominated debris flow deposits are the pervasive ones. Intensely sheared thin layers (5- to 20 cm) with sharp bases, displayed as successive layers at the base of mud/debris flow deposits, or as isolated depositional units interbedded in hemipelagic sediments, are as interesting, as enigmatic. They are interpreted as basal self-lubricating layers, of having high shear stress and pore pressures, over which the mud/debris flows were able to travel for very long distances.

Alternative Fuels Data Center: Charging Plug-In Electric Vehicles in Public

Science.gov Websites

in Public to someone by E-mail Share Alternative Fuels Data Center: Charging Plug-In Electric Vehicles in Public on Facebook Tweet about Alternative Fuels Data Center: Charging Plug-In Electric Vehicles in Public on Twitter Bookmark Alternative Fuels Data Center: Charging Plug-In Electric Vehicles in

Plug-In Hybrid Electric Vehicle Basics | NREL

Science.gov Websites

Plug-In Hybrid Electric Vehicle Basics Plug-In Hybrid Electric Vehicle Basics Imagine being able to one that's in a standard hybrid electric vehicle. The larger battery pack allows plug-in hybrids to fuel from its onboard tank, and this provides a driving range (the distance a vehicle can travel

Alternative Fuels Data Center: Maintenance and Safety of Hybrid and Plug-In

Science.gov Websites

Electric Vehicles Maintenance and Safety of Hybrid and Plug-In Electric Vehicles to someone by E-mail Share Alternative Fuels Data Center: Maintenance and Safety of Hybrid and Plug-In Electric Vehicles on Facebook Tweet about Alternative Fuels Data Center: Maintenance and Safety of Hybrid and Plug

Unbalanced-flow, fluid-mixing plug with metering capabilities

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor); Van Buskirk, Paul D. (Inventor)

2009-01-01

A fluid mixer plug has holes formed therethrough such that a remaining portion is closed to fluid flow. The plug's inlet face defines a central circuit region and a ring-shaped region with the ring-shaped region including at least some of the plug's remaining portion so-closed to fluid flow. This remaining portion or closed region at each radius R of the ring shaped region satisfies a radius independent, flow-based relationship. Entry openings are defined in the plug's inlet face in correspondence with the holes. The entry openings define an open flow area at each radius of the ring-shaped region. The open flow area at each such radius satisfies the inverse of the flow-based relationship defining the closed regions of the plug.

A Report on Superfluid Helium Flow Through Porous Plugs for Space Science Applications

NASA Technical Reports Server (NTRS)

Mason, F. C.

1983-01-01

As a background for the study of the nature of superfluid helium flow through porous plugs for other space science uses, preliminary tests on various plugs of a given material, diameter, height, and filtration grade have been performed. Two characteristics of the plugs, pore size and number of channels, have been determined by the bubble test and warm flow test of helium gas through the plugs, respectively. Tests on the flow of He II through the plugs have also been performed. An obvious feature of the results of these tests is that for isothermal measurements of pressure versus mass flow rate below approximately 2.10 K, the flow is separated into two different regimes, indicative of the occurrence of a critical phenomenon.

Reducing or stopping the uncontrolled flow of fluid such as oil from a well

DOEpatents

Hermes, Robert E

2014-02-18

The uncontrolled flow of fluid from an oil or gas well may be reduced or stopped by injecting a composition including 2-cyanoacrylate ester monomer into the fluid stream. Injection of the monomer results in a rapid, perhaps instantaneous, polymerization of the monomer within the flow stream of the fluid. This polymerization results in formation of a solid plug that reduces or stops the flow of additional fluid from the well.

The Utilization of the Microflora Indigenous to and present in Oil-Bearing Formations to Selectively Plug the More Porous Zones Thereby Increasing Oil Recovery During Waterflooding

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

Alex A. Vadie; Lewis R. Brown

1998-04-20

The use of indigenous microbes as a method of profile control in waterfloods is investigated. It is expected that as the microbial population is induced to increase the expanded biomass will selectively block the more permeable zones of the reservoir thereby forcing injection water to flow through the less permeable zones which will result in improved sweep efficiency.

Comparative Evaluation of TRAIL, FGF-2 and VEGF-A-Induced Angiogenesis In Vitro and In Vivo

PubMed Central

Cartland, Siân P.; Genner, Scott W.; Zahoor, Amna; Kavurma, Mary M.

2016-01-01

Tumor necrosis-factor-related apoptosis-inducing ligand (TRAIL) has been implicated in angiogenesis; the growth of new blood vessels from an existing vessel bed. Our aim was to compare pro-angiogenic responses of TRAIL, vascular endothelial growth-factor-A (VEGF-A) and fibroblast growth-factor-2 (FGF-2) either separately (10 ng/mL) or in combination, followed by the assessment of proliferation, migration and tubule formation using human microvascular endothelial-1 (HMEC-1) cells in vitro. Angiogenesis was also measured in vivo using the Matrigel plug assay. TRAIL and FGF-2 significantly augmented HMEC-1 cell proliferation and migration, with combination treatment having an enhanced effect on cell migration only. In contrast, VEGF-A did not stimulate HMEC-1 migration at 10 ng/mL. Tubule formation was induced by all three factors, with TRAIL more effective compared to VEGF-A, but not FGF-2. TRAIL at 400 ng/mL, but not VEGF-A, promoted CD31-positive staining into the Matrigel plug. However, FGF-2 was superior, stimulating cell infiltration and angiogenesis better than TRAIL and VEGF-A in vivo. These findings demonstrate that each growth factor is more effective at different processes of angiogenesis in vitro and in vivo. Understanding how these molecules stimulate different processes relating to angiogenesis may help identify new strategies and treatments aimed at inhibiting or promoting dysregulated angiogenesis in people. PMID:27918462

Comparative Evaluation of TRAIL, FGF-2 and VEGF-A-Induced Angiogenesis In Vitro and In Vivo.

PubMed

Cartland, Siân P; Genner, Scott W; Zahoor, Amna; Kavurma, Mary M

2016-12-02

Tumor necrosis-factor-related apoptosis-inducing ligand (TRAIL) has been implicated in angiogenesis; the growth of new blood vessels from an existing vessel bed. Our aim was to compare pro-angiogenic responses of TRAIL, vascular endothelial growth-factor-A (VEGF-A) and fibroblast growth-factor-2 (FGF-2) either separately (10 ng/mL) or in combination, followed by the assessment of proliferation, migration and tubule formation using human microvascular endothelial-1 (HMEC-1) cells in vitro. Angiogenesis was also measured in vivo using the Matrigel plug assay. TRAIL and FGF-2 significantly augmented HMEC-1 cell proliferation and migration, with combination treatment having an enhanced effect on cell migration only. In contrast, VEGF-A did not stimulate HMEC-1 migration at 10 ng/mL. Tubule formation was induced by all three factors, with TRAIL more effective compared to VEGF-A, but not FGF-2. TRAIL at 400 ng/mL, but not VEGF-A, promoted CD31-positive staining into the Matrigel plug. However, FGF-2 was superior, stimulating cell infiltration and angiogenesis better than TRAIL and VEGF-A in vivo. These findings demonstrate that each growth factor is more effective at different processes of angiogenesis in vitro and in vivo. Understanding how these molecules stimulate different processes relating to angiogenesis may help identify new strategies and treatments aimed at inhibiting or promoting dysregulated angiogenesis in people.

Sandstone provenance and U-Pb ages of detrital zircons from Permian-Triassic forearc sediments within the Sukhothai Arc, northern Thailand: Record of volcanic-arc evolution in response to Paleo-Tethys subduction

NASA Astrophysics Data System (ADS)

Hara, Hidetoshi; Kunii, Miyuki; Miyake, Yoshihiro; Hisada, Ken-ichiro; Kamata, Yoshihito; Ueno, Katsumi; Kon, Yoshiaki; Kurihara, Toshiyuki; Ueda, Hayato; Assavapatchara, San; Treerotchananon, Anuwat; Charoentitirat, Thasinee; Charusiri, Punya

2017-09-01

Provenance analysis and U-Pb dating of detrital zircons in Permian-Triassic forearc sediments from the Sukhothai Arc in northern Thailand clarify the evolution of a missing arc system associated with Paleo-Tethys subduction. The turbidite-dominant formations within the forearc sediments include the Permian Ngao Group (Kiu Lom, Pha Huat, and Huai Thak formations), the Early to earliest Late Triassic Lampang Group (Phra That and Hong Hoi formations), and the Late Triassic Song Group (Pha Daeng and Wang Chin formations). The sandstones are quartzose in the Pha Huat, Huai Thak, and Wang Chin formations, and lithic wacke in the Kiu Lom, Phra That, Hong Hoi and Pha Daeng formations. The quartzose sandstones contain abundant quartz, felsic volcanic and plutonic fragments, whereas the lithic sandstones contain mainly basaltic to felsic volcanic fragments. The youngest single-grain (YSG) zircon U-Pb age generally approximates the depositional age in the study area, but in the case of the limestone-dominant Pha Huat Formation the YSG age is clearly older. On the other hand, the youngest cluster U-Pb age (YC1σ) represents the peak of igneous activity in the source area. Geological evidence, geochemical signatures, and the YC1σ ages of the sandstones have allowed us to reconstruct the Sukhothai arc evolution. The initial Sukhothai Arc (Late Carboniferous-Early Permian) developed as a continental island arc. Subsequently, there was general magmatic quiescence with minor I-type granitic activity during the Middle to early Late Permian. In the latest Permian to early Late Triassic, the Sukhothai Arc developed in tandem with Early to Middle Triassic I-type granitic activity, Middle to Late Triassic volcanism, evolution of an accretionary complex, and an abundant supply of sediments from the volcanic rocks to the trench through a forearc basin. Subsequently, the Sukhothai Arc became quiescent as the Paleo-Tethys closed after the Late Triassic. In addition, parts of sediments of supposed Devonian-Carboniferous age within the Sukhothai Arc were revised as the Triassic Lampang Group, and the Early Cretaceous Khorat Group.

Uranium migration and favourable sites of potential radioelement concentrations in Gabal Umm Hammad area, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Youssef, Mohamed A. S.; Sabra, Mohamed Elsadek M.; Abdeldayem, Abdelaziz L.; Masoud, Alaa A.; Mansour, Salah A.

2017-12-01

Airborne gamma-ray spectrometric data, covering Gabal Umm Hammad area, near Quseir City, in the Eastern Desert of Egypt, has been utilized to identify the uranium migration path, and U, Th and K-favorability indices. The following of the uranium migration technique enabled estimation of the amount of migrated uranium, in and out of the rock units. Investigation of the Taref Formation, Nakhil Formation, Tarawan Formation and Dawi Formation shows large negative amount of uranium migration, indicating that uranium leaching is outward from the geologic body toward surrounding rock units. Moreover, calculation of the U, Th and K-favorability indices has been carried out for the various rock units to locate the rocks having the highest radioelement potentialities. The rock units that possess relatively major probability of uranium potentiality include Mu‧tiq Group, weakly deformed granitic rocks, and Trachyte plugs and sheets. Meanwhile, the rock units with major potential of Th-index are Taref Formation, Quseir Formation and Dawi Formation. The rock units with major potential of K-index are Dokhan volcanic and Mu‧tiq group.

Gravity-regulated formation of the peg in developing cucumber seedlings

NASA Technical Reports Server (NTRS)

Takahashi, H.; Scott, T. K.

1994-01-01

It has been proposed that peg formation in the vascular transition region (TR zone) between the hypocotyl and the root in Cucurbitaceae seedlings is a gravimorphogenetic phenomenon. Initiation of the peg became visible 36 h after imbibition when cucumber (Cucumis sativus L. cv. Burpee Hybrid II) seeds were germinated in a horizontal position at 24 degrees C in the dark. Simultaneously, sedimented amyloplasts (putative statoliths) were apparent in the sheath cells surrounding the vascular strands, and in the cortical cells immediately adjacent to them, in the TR zone. In contrast, the other cortical cells, some of which were destined to develop into the peg, contained amyloplasts which were not sedimented. These results suggest that the graviperception mechanism for peg formation may be like that of statoliths in shoot gravitropism. By 48 h following imbibition, the cells of the TR zone still had sedimented amyloplasts but had lost their sensitivity to gravity, possibly because of their maturation.

Foraminiferal and radiolarian biostratigraphy of the youngest (Late Albian through Late Cenomanian) sediments of the Tatra massif, Central Western Carpathians

NASA Astrophysics Data System (ADS)

Bąk, Krzysztof; Bąk, Marta

2013-06-01

Bąk, K. and Bąk M. 2013. Foraminiferal and radiolarian biostratigraphy of the youngest (Late Albian through Late Cenomanian) sediments of the Tatra massif, Central Western Carpathians. Acta Geologica Polonica, 63 (2), 223-237. Warszawa. The foraminiferal and radiolarian biostratigraphy of selected sections of the Zabijak Formation, the youngest sediments of the Tatra massif (Central Western Carpathians), have been studied. Benthic foraminifers, mainly agglutinated species, occur abundantly and continuously throughout the studied succession, while planktic foraminifers are generally sparse. Five planktic and two benthic foraminiferal zones have been recognized. The marly part of the Zabijak Formation comprises the Pseudothalmanninella ticinensis (Upper Albian) through the Rotalipora cushmani (Upper Cenomanian) planktic foraminiferal zones, and the Haplophragmoides nonioninoides and Bulbobaculites problematicus benthic foraminiferal zones. The radiolarians were recognized exclusively in the Lower Cenomanian part of the formation.

Statistics of Experiments on Cluster Formation and Transport in a Gravitational Field

NASA Technical Reports Server (NTRS)

Izmailov, Alexander F.; Myerson, Allan S.

1993-01-01

Metastable state relaxation in a gravitational field is investigated in the case of non-critical binary solutions. A relaxation description is presented in terms of the time-dependent Ginzburg-Landau formalism for a non-conserved order parameter. A new ansatz for solution of the corresponding partial nonlinear stochastic differential equation is discussed. It is proved that, for the supersaturated solution under consideration, the metastable state relaxation in a gravitational field leads to formation of solute concentration gradients due to the sedimentation of subcritical solute clusters. The pure discussion of the possible methods to compare theoretical results and experimental data related to solute sedimentation in a gravitational field is presented. It is shown that in order to describe these experiments it is necessary to deal both with the value of the solute concentration gradient and with its formation rate. The stochastic nature of the sedimentation process is shown.

Hydrogeochemical and stream sediment reconnaissance basic data for Palestine NTMS Quadrangle, Texas

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

Not Available

1979-05-04

Results of a reconnaissance geochemical survey of the Palestine Quadrangle are reported. Field and laboratory data are presented for 714 groundwater and 577 stream sediment samples. Statistical and areal distributions of uranium and possible uranium-related variables are displayed. A generalized geologic map of the survey area is provided, and pertinent geologic factors which may be of significance in evaluating the potential for uranium mineralization are briefly discussed. Groundwater data indicate that uranium concentrations above the 85th percentile occur primarily in the Caddell, Wellborn, and Manning Formations of the Jackson Group; and the Yegua Formation of the Claiborne Group. Saline watermore » trends are also prominent in these formations. Stream sediment data indicate that uranium values above the 85th percentile correlate with high concentrations of cerium, niobium, thorium, titanium, yttrium, and zirconium. This elemental suite probably indicates that uranium is associated with resistate and/or heavy minerals.« less

The Pliocene-Pleistocene sedimentary tectonic history of NW California

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

Stone, L.; Moley, K.; Aalto, K.R.

1993-04-01

A thick sequence of Late Miocene to Pleistocene sediments thought to represent deposition in a Neogene forearc basin are preserved in the structural basin referred to as the Eel River basin' located offshore of NW California and SE Oregon. The southern portion of this structural basin comes on land in the vicinity of Eureka where the marine and fluvial Wildcat Group is exposed. Basal Wildcat Group sediments are fluvial and littorial. Marine sandstones of the Wildcat Group contain K-spar concentrations of 5.5% and are believed to represent a fresh source. [sup 40]Ar/[sup 39]Ar laser probe analyses of Wildcat Group micasmore » yield dates of 52--57, 66--75, 128.5 and 299--303 Ma. The presence of Idaho detritus throughout the Neogene Wildcat Group indicates that the Klamath Mountains remained low during the Pliocene and early Pleistocene. Younger fluvial sediments in this region contain primarily locally derived detritus indicating local uplift of the Klamath Mountains. To the north, at Crescent City, thin remnants of the near-shore Saint George Formation and the eastern estuarine and fluvial Wimer Formation are lowermost Pliocene in age (5 ma). The presence of the highly erodible Wilmer Formation on uplifted plateaus in an area of extreme rainfall suggest that these sediments represent only the lowermost portion of an originally much thicker sequence. Consequently, the sediments confined to the present day Eel River basin do not represent the lateral extent of the original forearc basin. Sandstones and conglomerates of the Saint George and Wimer Formation indicate a local Klamath provenance derivation.« less

Design and force analysis of end-effector for plug seedling transplanter.

PubMed

Jiang, Zhuohua; Hu, Yang; Jiang, Huanyu; Tong, Junhua

2017-01-01

Automatic transplanters have been very important in greenhouses since the popularization of seedling nurseries. End-effector development is a key technology for transplanting plug seedlings. Most existing end-effectors have problems with holding root plugs or releasing plugs. An efficient end-effector driven by a linear pneumatic cylinder was designed in this study, which could hold root plugs firmly and release plugs easily. This end-effector with four needles could clamp the plug simultaneously while the needles penetrate into the substrate. The depth and verticality of the needles could be adjusted conveniently for different seedling trays. The effectiveness of this end-effector was tested by a combinational trial examining three seedling nursery factors (the moisture content of the substrate, substrate bulk density and the volume proportion of substrate ingredients). Results showed that the total transplanting success rate for the end-effector was 100%, and the root plug harm rate was below 17%. A force measure system with tension and pressure transducers was installed on the designed end-effector. The adhesive force FL between the root plug and the cell of seedling trays and the extrusion force FK on the root plug were measured and analyzed. The results showed that all three variable factors and their interactions had significant effects on the extrusion force. Each factor had a significant effect on adhesive force. Additionally, it was found that the end-effector did not perform very well when the value of FK/FL was beyond the range of 5.99~8.67. This could provide a scientific basis for end-effector application in transplanting.

Design and force analysis of end-effector for plug seedling transplanter

PubMed Central

Hu, Yang; Jiang, Huanyu; Tong, Junhua

2017-01-01

Automatic transplanters have been very important in greenhouses since the popularization of seedling nurseries. End-effector development is a key technology for transplanting plug seedlings. Most existing end-effectors have problems with holding root plugs or releasing plugs. An efficient end-effector driven by a linear pneumatic cylinder was designed in this study, which could hold root plugs firmly and release plugs easily. This end-effector with four needles could clamp the plug simultaneously while the needles penetrate into the substrate. The depth and verticality of the needles could be adjusted conveniently for different seedling trays. The effectiveness of this end-effector was tested by a combinational trial examining three seedling nursery factors (the moisture content of the substrate, substrate bulk density and the volume proportion of substrate ingredients). Results showed that the total transplanting success rate for the end-effector was 100%, and the root plug harm rate was below 17%. A force measure system with tension and pressure transducers was installed on the designed end-effector. The adhesive force FL between the root plug and the cell of seedling trays and the extrusion force FK on the root plug were measured and analyzed. The results showed that all three variable factors and their interactions had significant effects on the extrusion force. Each factor had a significant effect on adhesive force. Additionally, it was found that the end-effector did not perform very well when the value of FK/FL was beyond the range of 5.99~8.67. This could provide a scientific basis for end-effector application in transplanting. PMID:28678858

Selenium concentrations in the razorback sucker (Xyrauchen texanus): Substitution of non-lethal muscle plugs for muscle tissue in contaminant assessment

USGS Publications Warehouse

Waddell, B.; May, T.

1995-01-01

A single muscle plug was collected from each of 25 live razorback suckers inhabiting the Colorado River basin and analyzed for selenium by instrumental neutron activation. Eight fish from Ashley Creek and three from Razorback Bar exhibited selenium concentrations exceeding 8 μg/g, a level associated with reproductive failure in fish. Concentrations of selenium in eggs and milt were significantly correlated with selenium concentrations in muscle plugs and together indicate a possible explanation for the decline of this species in the Colorado River basin. Muscle plugs (<50mg) and muscle tissue (20 g) were collected from dorsal, anterior, and posterior areas of common carp, flannelmouth sucker, and an archived razorback sucker and analyzed for selenium. Concentrations of selenium in muscle plugs were significantly correlated with selenium concentrations in muscle tissue from the same location and fish (r=0.97). Coefficients of variation for selenium concentrations in each fish were <6.5% for muscle tissue, but ranged from 1.5 to 32.4% for muscle plugs. Increased variation in muscle plugs was attributed to lower selenium concentrations found in the anterior muscle plugs of flannelmouth suckers. Mean selenium concentrations in muscle plugs and tissue from dorsal and posterior areas and muscle tissue from the anterior area were not significantly different. The non-lethal collection of a muscle plug from dorsal and posterior areas of the razorback sucker and other fish species may provide an accurate assessment of selenium concentrations that exist in adjacent muscle tissue.

Modeling the Formation of Hydrate-Filled Veins in Fine-Grained Sediments from in Situ Microbial Methane

NASA Astrophysics Data System (ADS)

Malinverno, A.; Cook, A.; Daigle, H.

2016-12-01

Continental margin sediments are dominantly fine-grained silt and clay, and methane hydrates in these sediments are often found in semi-vertical veins and fractures. In several instances, these hydrate veins occupy discrete depth intervals that are a few tens of meters thick and are surrounded by hydrate-free sediments. As they are not connected with gas sources beneath the base of the gas hydrate stability zone (GHSZ), these isolated hydrate-bearing intervals have been interpreted as formed by in situ microbial methane. To investigate the formation of these hydrate deposits, we applied a time-dependent advection-diffusion-reaction model that includes the effects of sedimentation, compaction, solute diffusion, and microbial methane generation. Microbial methane generation depends on the amount of metabolizable organic carbon deposited at the seafloor, whose progressive degradation produces methane beneath the sulfate reduction zone. If the amount of organic carbon entering the methanogenic zone is kept constant in time, we found that the computed amounts of hydrate formed in discrete intervals within the GHSZ are well below those estimated from observations. On the other hand, if the deposition of organic carbon is higher in a given time interval, methane generation during burial is more intense in the corresponding sediment interval, resulting in enhanced hydrate formation. With variations in organic carbon deposition comparable to those generally observed in continental margins, our model was able to reproduce the methane hydrate contents that were estimated from drilling. These results support the suggestion that in situ microbial generation associated with transient organic carbon deposition is the source of methane that forms isolated intervals of hydrate-filled veins in fine-grained sediments.

Modeling the Formation of Hydrate-Filled Veins in Fine-Grained Sediments from in Situ Microbial Methane

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

Malinverno, Alberto; Cook, Ann; Daigle, Hugh

Continental margin sediments are dominantly fine-grained silt and clay, and methane hydrates in these sediments are often found in semi-vertical veins and fractures. In several instances, these hydrate veins occupy discrete depth intervals that are a few tens of meters thick and are surrounded by hydrate-free sediments. As they are not connected with gas sources beneath the base of the gas hydrate stability zone (GHSZ), these isolated hydrate-bearing intervals have been interpreted as formed by in situ microbial methane. To investigate the formation of these hydrate deposits, we applied a time-dependent advection-diffusion-reaction model that includes the effects of sedimentation, compaction,more » solute diffusion, and microbial methane generation. Microbial methane generation depends on the amount of metabolizable organic carbon deposited at the seafloor, whose progressive degradation produces methane beneath the sulfate reduction zone. If the amount of organic carbon entering the methanogenic zone is kept constant in time, we found that the computed amounts of hydrate formed in discrete intervals within the GHSZ are well below those estimated from observations. On the other hand, if the deposition of organic carbon is higher in a given time interval, methane generation during burial is more intense in the corresponding sediment interval, resulting in enhanced hydrate formation. With variations in organic carbon deposition comparable to those generally observed in continental margins, our model was able to reproduce the methane hydrate contents that were estimated from drilling. These results support the suggestion that in situ microbial generation associated with transient organic carbon deposition is the source of methane that forms isolated intervals of hydrate-filled veins in fine-grained sediments.« less

Numerical investigation of soil plugging effect inside sleeve of cast-in-place piles driven by vibratory hammers in clays.

PubMed

Xiao, Yong Jie; Chen, Fu Quan; Dong, Yi Zhi

2016-01-01

During driving sleeve of cast-in-place piles by vibratory hammers, soils were squeezed into sleeve and then soil plugging was formed. The physic-mechanical properties of the soil plug have direct influence on the load transmission between the sleeve wall and soil plug. Nevertheless, the researches on this issue are insufficient. In this study, finite element and infinite element coupling model was introduced, through the commercial code ABAQUS, to simulate the full penetration process of the sleeve driven from the ground surface to the desired depth by applying vibratory hammers. The research results indicated that the cyclic shearing action decreases both in soil shear strength and in granular cementation force when the sleeve is driven by vibratory hammers, which leads to a partially plugged mode of the soil plug inside the sleeve. Accordingly, the penetration resistance of sleeve driven by vibratory hammers is the smallest compared to those by other installation methods. When driving the sleeve, the annular soil arches forming in the soil plug at sleeve end induce a significant rise in the internal shaft resistance. Moreover, the influence of vibration frequencies, sleeve diameters, and soil layer properties on the soil plug was investigated in detail, and at the same time improved formulas were brought forward to describe the soil plug resistance inside vibratory driven sleeve.

Lithologic interpretation of the De Braga No. 2 and Richard Weishaupt No. 1 geothermal wells, Stillwater project, Churchill County, Nevada

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

Sibbett, B.S.; Blackett, R.E.

1982-02-01

Lithologies penetrated throughout the upper 732 to 838 m (2400 to 2750 ft) within the Stillwater prospect area are terrigenous sediments of Pleistocene to Recent age. A sill of dacite to andesite composition with a thickness variable between 122 to 208 m (400 to 680 ft) is present below the terrigenous sediments. Between the base of the sill and the top of the Bunejug Formation are intercalated volcanic and sedimentary rocks. All formations overlying the Bunejug Formation are probably of Pleistocene age. The basalt and basaltic-andesite flows and ash below the depth of approximately 1128 m (3700 ft) are hereinmore » assigned to the Bunejug Formation (Morrison, 1964) of Pliocene and possibly early Pleistocene age. The Bunejug Formation is a thick sequence of basalt to andesite flows and hyaloclastite exposed in the mountains surrounding the south half of the Carson Desert. The De Braga No. 2 well bottomed in Bunejug volcanics at a depth of 2109 m (6920 ft). The Richard Weishaupt No. 1 well penetrated the entire Bunejug sequence and entered felsic volcanics and tuffaceous sediments, which possibly represent part of the Truckee Formation, at a depth of approximately 2412 m (7915 ft).« less

A review of oil-suspended particulate matter aggregation--a natural process of cleansing spilled oil in the aquatic environment.

PubMed

Sun, Juan; Zheng, Xilai

2009-10-01

It has been acknowledged that following an oil spill in coastal areas where suspended particulate matter (SPM) is rich, aggregation between oil and SPM can be naturally formed. This kind of aggregation product is termed as oil-SPM aggregates (OSAs). Because OSAs are not as sticky to the shorelines as crude oil and the oil-water contact area is greatly increased due to the formation of OSAs, both oil dispersion into the water body and oil biodegration would be significantly enhanced. In this review article, the authors (1) describe in detail the mechanism of OSA formation and controlling parameters which can influence OSA formation (the parameters discussed include the oil nature and properties, sediment types and concentrations, and the environmental factors such as salinity, temperature and mixing energy); (2) briefly review qualitative and quantitative methods used for characterization of OSA formation (two main methods used for the OSA characterization are the UV epi-fluorescence microscopy and gas chromatography equipped with flame ionization detector (GC-FID); (3) elucidate the applications of OSA formation in oil spill response strategies including natural attenuation, sediment relocation, and sediment mixing; and (4) discuss research needs in the future which would further improve our understanding of OSA formation and move towards the development of adequate oil behaviour models.

PLUG STORAGE BUILDING, TRA611, AWAITS SHIELDING SOIL TO BE PLACED ...

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

PLUG STORAGE BUILDING, TRA-611, AWAITS SHIELDING SOIL TO BE PLACED OVER PLUG STORAGE TUBES. WING WALLS WILL SUPPORT EARTH FILL. MTR, PROCESS WATER BUILDING, AND WORKING RESERVOIR IN VIEW BEYOND PLUG STORAGE. CAMERA FACES NORTHEAST. INL NEGATIVE NO. 2949. Unknown Photographer, 7/30/1951 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

Alternative Fuels Data Center: Los Angeles Sets the Stage for Plug-In

Science.gov Websites

Electric Vehicles Los Angeles Sets the Stage for Plug-In Electric Vehicles to someone by E-mail Share Alternative Fuels Data Center: Los Angeles Sets the Stage for Plug-In Electric Vehicles on Facebook Tweet about Alternative Fuels Data Center: Los Angeles Sets the Stage for Plug-In Electric

30 CFR 250.1715 - How must I permanently plug a well?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Zones in open hole, Cement plug(s) set from at least 100 feet below the bottom to 100 feet above the top... cement plug, set by the displacement method, at least 100 feet above and below deepest casing shoe; (ii) A cement retainer with effective back-pressure control set 50 to 100 feet above the casing shoe, and...

30 CFR 250.1715 - How must I permanently plug a well?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Zones in open hole, Cement plug(s) set from at least 100 feet below the bottom to 100 feet above the top... cement plug, set by the displacement method, at least 100 feet above and below deepest casing shoe; (ii) A cement retainer with effective back-pressure control set 50 to 100 feet above the casing shoe, and...

30 CFR 250.1715 - How must I permanently plug a well?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Zones in open hole, Cement plug(s) set from at least 100 feet below the bottom to 100 feet above the top... cement plug, set by the displacement method, at least 100 feet above and below deepest casing shoe; (ii) A cement retainer with effective back-pressure control set 50 to 100 feet above the casing shoe, and...

30 CFR 250.1715 - How must I permanently plug a well?

Code of Federal Regulations, 2011 CFR

2011-07-01

... in open hole Cement plug(s) set from at least 100 feet below the bottom to 100 feet above the top of... cement plug, set by the displacement method, at least 100 feet above and below deepest casing shoe;(ii) A cement retainer with effective back-pressure control set 50 to 100 feet above the casing shoe, and a...

Electric and Plug-In Hybrid Electric Fleet Vehicle Testing | Transportation

Science.gov Websites

Research | NREL Electric and Plug-In Hybrid Electric Fleet Vehicle Evaluations Electric and Plug-In Hybrid Electric Fleet Vehicle Evaluations How Electric and Plug-In Hybrid Electric Vehicles Work EVs use batteries to store the electric energy that powers the motor. EV batteries are charged by

Fine-grained sediment gravity flow deposits induced by flood and lake slope failure events: examples of lacustrine varved sediments in Japan

NASA Astrophysics Data System (ADS)

Ishihara, Yoshiro; Sasaki, Yasunori; Sasaki, Hana; Onishi, Yuri

2016-04-01

Fine-grained sediment gravity flow deposits induced by flood and lake slope failure events are frequently intercalated in lacustrine successions. When sediment gravity flow deposits are present in varved sediments, it is suggested that they provide valuable information about sediment gravity flows, because they can easily trace laterally and can give the magnitude of erosion and recurrence interval of events. In addition, because large sedimentary bodies of stacked sediment gravity flow deposits in varved sediments of a calm lake are not suggested, a relatively simple depositional environment is expected. In the present study, we analysed sedimentary facies of sediment gravity flow deposits in varved lacustrine diatomites in the Middle Pleistocene Hiruzenbara and Miyajima formations in Japan, and concluded a depositional model of the lacustrine sediment gravity flow deposits. Varved diatomites: The Hiruzenbara Fm., a dammed lake fill as foots of Hiruzen Volcanos, is deposited during an interglacial period during MIS12 to 15. Varves of ca. 8000 yr were measured in a 20 m intercalating flood and lake slope failure-induced sediment gravity flow deposits. The Miyajima Fm., distributed in a paleo-caldera lake in NE Japan, includes many sediment gravity flow deposits possibly originated from fandeltas around the lake. These formations have differences in their depositional setting; the Hiruzebara Fm. was deposited in a large lake basin, whereas the Miyajima Fm. was deposited in a relatively small basin. Because of the depositional setting, intercalation of volcaniclastics is dominant in the Miyajima Fm. Lacustrine sediment gravity flow deposits: Sediment gravity flow deposits in both formations can be classified into flood- and lake slope failure-induced types based on the sedimentary facies. Composites of the both types are also found. Flood-induced types comprise fine-grained silts dominated by carbonaceous fragments, whereas lake slope failure-induced types are dominated by rip-up clasts of diatomite. The former is well continued in outcrops; however, the thickness of the latter is changeable and the lower contact is erosive. In the Hirzenbara Fm., flood-induced type includes epiphytic diatom valves as river inflows, whereas slope failure-induced type is composed of diatom valves of varved diatomite. Flood-induced types are suggested to be classified into hyperpycnal flow and hypopycnal flow types with regard to the presence of basal erosion. On the other hand, slope failure-induced types can be interpreted as debris flow deposits occurred in the lakes. Differences in the two types are also shown as bed-thickness frequency distributions indicating event magnitude.

Experimental Investigation of Shock-Cell Noise Reduction for Single Stream Nozzles in Simulated Flight

NASA Technical Reports Server (NTRS)

Yamamoto, K.; Brausch, J. F.; Balsa, T. F.; Janardan, B. A.; Knott, P. R.

1984-01-01

Seven single stream model nozzles were tested in the Anechoic Free-Jet Acoustic Test Facility to evaluate the effectiveness of convergent divergent (C-D) flowpaths in the reduction of shock-cell noise under both static and mulated flight conditions. The test nozzles included a baseline convergent circular nozzle, a C-D circular nozzle, a convergent annular plug nozzle, a C-D annular plug nozzle, a convergent multi-element suppressor plug nozzle, and a C-D multi-element suppressor plug nozzle. Diagnostic flow visualization with a shadowgraph and aerodynamic plume measurements with a laser velocimeter were performed with the test nozzles. A theory of shock-cell noise for annular plug nozzles with shock-cells in the vicinity of the plug was developed. The benefit of these C-D nozzles was observed over a broad range of pressure ratiosin the vicinity of their design conditions. At the C-D design condition, the C-D annual nozzle was found to be free of shock-cells on the plug.

Integrated geophysical surveys for mapping lati-andesite intrusive bodies, Chino Valley, Arizona

USGS Publications Warehouse

El-Kaliouby, Hesham; Sternberg, Ben K.; Hoffmann, John P.; Langenheim, V.E.

2012-01-01

Three different geophysical methods (magnetic, transient electromagnetic (TEM) and gravity) were used near Chino Valley, Arizona, USA in order to map a suspected lati-andesite intrusive body (plug) previously located by interpretation of aeromagnetic data. The magnetic and TEM surveys provided the best indication of the location and depth of the plug. The north-south spatial extent of this plug was estimated to be approximately 600 meters. The depth to the top of the plug was found from the TEM survey to be approximately 350 meters near the center of the survey. The location of the plug defined by the ground magnetic data is consistent with that from the TEM data. Gravity data mostly image the basin-basement interface with a small contribution from the plug of about 0.5 mGal. Results from this investigation can be used to help define the irregular subsurface topography caused by several intrusive lati-andesite plugs that could influence groundwater flow in the area.

A new flexible plug and play scheme for modeling, simulating, and predicting gastric emptying

PubMed Central

2014-01-01

Background In-silico models that attempt to capture and describe the physiological behavior of biological organisms, including humans, are intrinsically complex and time consuming to build and simulate in a computing environment. The level of detail of description incorporated in the model depends on the knowledge of the system’s behavior at that level. This knowledge is gathered from the literature and/or improved by knowledge obtained from new experiments. Thus model development is an iterative developmental procedure. The objective of this paper is to describe a new plug and play scheme that offers increased flexibility and ease-of-use for modeling and simulating physiological behavior of biological organisms. Methods This scheme requires the modeler (user) first to supply the structure of the interacting components and experimental data in a tabular format. The behavior of the components described in a mathematical form, also provided by the modeler, is externally linked during simulation. The advantage of the plug and play scheme for modeling is that it requires less programming effort and can be quickly adapted to newer modeling requirements while also paving the way for dynamic model building. Results As an illustration, the paper models the dynamics of gastric emptying behavior experienced by humans. The flexibility to adapt the model to predict the gastric emptying behavior under varying types of nutrient infusion in the intestine (ileum) is demonstrated. The predictions were verified with a human intervention study. The error in predicting the half emptying time was found to be less than 6%. Conclusions A new plug-and-play scheme for biological systems modeling was developed that allows changes to the modeled structure and behavior with reduced programming effort, by abstracting the biological system into a network of smaller sub-systems with independent behavior. In the new scheme, the modeling and simulation becomes an automatic machine readable and executable task. PMID:24917054

Methane in groundwater from a leaking gas well, Piceance Basin, Colorado, USA.

PubMed

McMahon, Peter B; Thomas, Judith C; Crawford, John T; Dornblaser, Mark M; Hunt, Andrew G

2018-09-01

Site-specific and regional analysis of time-series hydrologic and geochemical data collected from 15 monitoring wells in the Piceance Basin indicated that a leaking gas well contaminated shallow groundwater with thermogenic methane. The gas well was drilled in 1956 and plugged and abandoned in 1990. Chemical and isotopic data showed the thermogenic methane was not from mixing of gas-rich formation water with shallow groundwater or natural migration of a free-gas phase. Water-level and methane-isotopic data, and video logs from a deep monitoring well, indicated that a shale confining layer ~125m below the zone of contamination was an effective barrier to upward migration of water and gas. The gas well, located 27m from the contaminated monitoring well, had ~1000m of uncemented annular space behind production casing that was the likely pathway through which deep gas migrated into the shallow aquifer. Measurements of soil gas near the gas well showed no evidence of methane emissions from the soil to the atmosphere even though methane concentrations in shallow groundwater (16 to 20mg/L) were above air-saturation levels. Methane degassing from the water table was likely oxidized in the relatively thick unsaturated zone (~18m), thus rendering the leak undetectable at land surface. Drilling and plugging records for oil and gas wells in Colorado and proxies for depth to groundwater indicated thousands of oil and gas wells were drilled and plugged in the same timeframe as the implicated gas well, and the majority of those wells were in areas with relatively large depths to groundwater. This study represents one of the few detailed subsurface investigations of methane leakage from a plugged and abandoned gas well. As such, it could provide a useful template for prioritizing and assessing potentially leaking wells, particularly in cases where the leakage does not manifest itself at land surface. Published by Elsevier B.V.

Methane in groundwater from a leaking gas well, Piceance Basin, Colorado, USA

USGS Publications Warehouse

McMahon, Peter B.; Thomas, Judith C.; Crawford, John T.; Dornblaser, Mark M.; Hunt, Andrew G.

2018-01-01

Site-specific and regional analysis of time-series hydrologic and geochemical data collected from 15 monitoring wells in the Piceance Basin indicated that a leaking gas well contaminated shallow groundwater with thermogenic methane. The gas well was drilled in 1956 and plugged and abandoned in 1990. Chemical and isotopic data showed the thermogenic methane was not from mixing of gas-rich formation water with shallow groundwater or natural migration of a free-gas phase. Water-level and methane-isotopic data, and video logs from a deep monitoring well, indicated that a shale confining layer ~125 m below the zone of contamination was an effective barrier to upward migration of water and gas. The gas well, located 27 m from the contaminated monitoring well, had ~1000 m of uncemented annular space behind production casing that was the likely pathway through which deep gas migrated into the shallow aquifer. Measurements of soil gas near the gas well showed no evidence of methane emissions from the soil to the atmosphere even though methane concentrations in shallow groundwater (16 to 20 mg/L) were above air-saturation levels. Methane degassing from the water table was likely oxidized in the relatively thick unsaturated zone (~18 m), thus rendering the leak undetectable at land surface. Drilling and plugging records for oil and gas wells in Colorado and proxies for depth to groundwater indicated thousands of oil and gas wells were drilled and plugged in the same timeframe as the implicated gas well, and the majority of those wells were in areas with relatively large depths to groundwater. This study represents one of the few detailed subsurface investigations of methane leakage from a plugged and abandoned gas well. As such, it could provide a useful template for prioritizing and assessing potentially leaking wells, particularly in cases where the leakage does not manifest itself at land surface.

How Does Decommissioning Forest Roads Effect Hydrologic and Geomorphic Risk?

NASA Astrophysics Data System (ADS)

Black, T.; Luce, C.; Cissel, R. M.; Nelson, N.; Staab, B.

2010-12-01

The US Forest Service is investigating road decommissioning projects to understand how treatments change hydrologic and geomorphic risks. Road treatment effect was measured using a before after control impact design (BACI), using the Geomorphic Road Analysis and Inventory Package (http://www.fs.fed.us/GRAIP). This suite of inventory and analysis tools evaluates: road-stream hydrologic connectivity, fine sediment production and delivery, shallow landslide risk, gully initiation risk, and risks associated with stream crossing failures. The Skokomish River study site is steep and wet and received a high intensity treatment including the removal of stream crossing pipes and fills, all ditch relief pipes and a full hillslope recontouring. Road to stream hydrologic connectivity was reduced by 70%. The treatments reduced fine sediment delivery by 21.8 tons or 81%. The removal of the stream crossing culverts and large associated road fills eliminated the risk of pipe plugging related failures and the eventual erosion of over 4,000 m3 of fill. The slope stability risk was assessed using a modified version of SINMAP (Pack et al, 2005). Risk below drain point locations on the original road was reduced as water was redistributed across the hillslope to waterbars and diffuse drainage. It is unclear; however, if landslide risk was reduced across the entire treated road length because treatments slightly increased risk in some areas where new concentrated drainage features were added above steep slopes. Similarly, values of a gully index ESI (Istanbulluoglu et al, 2003), were reduced at many of the original drainage points, however some new drainage was added. ESI values still exceed a predicted conservative initiation thresholds at some sites, therefore it is uncertain if gully risk will be changed. Mann Creek occupies a moderately steep mid-elevation site in Southern Idaho. The high intensity treatments removed all constructed road drainage features including stream crossing pipes and fills, and recontoured the hillslope. The length of road that was hydrologically connected to streams was reduced by 2,923 m, or 97%. The model predicts that fine sediment delivery was reduced by 98%, to 1.0 ton annually. The risk presented by stream crossings becoming plugged was eliminated. The potential for streamflow diversion onto roads and hillslopes was precluded. The slope stability risk below drain point locations on the original road was reduced as water was no longer concentrated and discharged through a single drainage feature. Treatments are predicted to return slope stability to near undisturbed levels. Gully initiation risks, already low prior to treatment, may be reduced to negligible values. Results from these two case studies suggest that high intensity road decommissioning can be effective at reducing the risk of road sediment delivery, hydrologic connectivity and failures associated with stream crossings. Post storm monitoring will help validate these predictions and reduce uncertainty around the hydrology of decommissioned roads. If decommissioned roads continue to concentrate water and discharge it onto steep slopes, landslides and gully risk may remain elevated.

Static Gas-Charging Plug

NASA Technical Reports Server (NTRS)

Indoe, William

2012-01-01

A gas-charging plug can be easily analyzed for random vibration. The design features two steeped O-rings in a radial configuration at two different diameters, with a 0.050-in. (.1.3-mm) diameter through-hole between the two O-rings. In the charging state, the top O-ring is engaged and sealing. The bottom O-ring outer diameter is not squeezed, and allows air to flow by it into the tank. The inner diameter is stretched to plug the gland diameter, and is restrained by the O-ring groove. The charging port bushing provides mechanical stop to restrain the plug during gas charge removal. It also prevents the plug from becoming a projectile when removing gas charge from the accumulator. The plug can easily be verified after installation to ensure leakage requirements are met.

High temperature penetrator assembly with bayonet plug and ramp-activated lock

NASA Technical Reports Server (NTRS)

Wood, K. E. (Inventor)

1982-01-01

A penetration apparatus, for very high temperature applications in which a base plug is inserted into an opening through a bulkhead is described. The base plug has a head shape and is seated against the highest temperature surface of the bulkhead, which may be the skin of the nose cone or other part of a space vehicle intended for nondestructive atmospheric reentry. From the second side of the bulkhead at which the less severe environment is extant, a bayonet plug is inserted into the base plug and engages an internal shoulder at about 90 deg rotation. The bayonet plug has an integral flanged portion and a pair of ramping washers which are located between the flange and the second bulkhead surface with a spacing washer as necessary.

Ice rafting of fine-grained sediment, a sorting and transport mechanism, Beaufort Sea, Alaska.

USGS Publications Warehouse

Barnes, P.W.; Reimnitz, E.; Fox, D.

1982-01-01

The presence of turbid, sediment-rich fast ice in the Arctic is a major factor affecting transport of fine-grained sediment. Observers have documented the widespread, sporadic occurrence of sediment- rich fast ice in both the Beaufort and Bering Seas. The occurrence of sediment in only the upper part of the seasonal fast ice indicates that sediment-rich ice forms early during ice growth. The most likely mechanism requires resuspension of nearshore bottom sediment during storms, accompanied by formation of frazil ice and subsequent lateral advection before the fast ice is stabilized. We estimate that the sediment incorporated in the Beaufort ice canopy formed a significant proportion of the seasonal influx of terrigenous fine-grained sediment. The dominance of fine-grained sediment suggests that in the Arctic and sub-Arctic these size fractions may be ice rafted in greater volumes than the coarse fraction of traditionally recognized ice-rafted sediment. -from Authors

Soft-sediment deformation structures from an ice-marginal storm-tide interactive system, Permo-Carboniferous Talchir Formation, Talchir Coalbasin, India

NASA Astrophysics Data System (ADS)

Bhattacharya, H. N.; Bhattacharya, Biplab

2010-01-01

Permo-Carboniferous Talchir Formation, Talchir Coalbasin, India, records sedimentation during a phase of climatic amelioration in an ice-marginal storm-affected shelf. Evidences of subtidal processes are preserved only under thick mud drapes deposited during waning storm phases. Various soft-sediment deformation structures in some sandstone/siltstone-mudstone interbeds, like syn-sedimentary faults, deformed laminations, sand-silt flows, convolute laminations and various flame structures, suggest liquefaction and fluidization of the beds due to passage of syn-depositional seismic shocks. In the Late Paleozoic ice-marginal shelf, such earthquake tremors could be generated by crustal movements in response to glacioisostatic adjustments of the basin floor.

Using UAVSAR Interferometry to Quantify the Geometry and Sediment Flux of Slow-moving Landslides in the Eel River Catchment, Northern California

NASA Astrophysics Data System (ADS)

Handwerger, A. L.; Huang, M. H.; Booth, A. M.; Fielding, E. J.

2017-12-01

Slow-moving, deep-seated landslides are highly erosive features that can remain active for periods of decades to centuries, playing a major role in landscape evolution. In the Eel River catchment, Northern California, slow-moving landslides are the primary contributor of sediment to the channel network, delivering >50% of the regional sediment flux despite occupying <10% of the landscape. While detailed, regional-scale measurements of surface kinematics can be made using remote sensing data like interferometric synthetic aperture radar (InSAR) or pixel tracking with SAR or optical images, subsurface measurements including landslide thickness are sparse. As a result, thickness estimates are often approximated from topographic data and globally-derived volume-area scaling relationships that may under- or over-predict landslide volumes by up to an order of magnitude at specific field sites. Furthermore, these relationships assume that the thickness is constant along the entire landslide body. To improve our measurements of landslide volume and kinematics we use repeat-pass InSAR from the NASA/JPL UAVSAR airborne radar acquired with 4 different look directions to quantify 3D surface displacements of 20 landslides across a 550 km2 area. We apply mass conservation techniques to 1) invert for landslide thickness and 2) solve for landslide rheology (i.e. depth-averaged velocity), which enables us to better constrain both volume and sediment flux. Our preliminary results indicate that the landslide thickness is highly variable with changes up to tens of meters along the landslide body. We also find that the landslides have a power law rheology with a plug-flow vertical velocity profile. Estimates of sediment flux contributed by individual landslides ranges from 103 to 104 m3/yr. The application of UAVSAR data represents a major advance from previous InSAR studies in this region and provides one of the first datasets containing 3D displacement measurements for multiple landslides occurring under nearly identical environmental conditions. Future work is aimed at using these subsurface and kinematic data to calculate landslide erosion rates and regional sediment flux and to better understand the controls on landslide dynamics over short- and long-timescales.

Combining data from multiple sources using the CUAHSI Hydrologic Information System

NASA Astrophysics Data System (ADS)

Tarboton, D. G.; Ames, D. P.; Horsburgh, J. S.; Goodall, J. L.

2012-12-01

The Consortium of Universities for the Advancement of Hydrologic Science, Inc. (CUAHSI) has developed a Hydrologic Information System (HIS) to provide better access to data by enabling the publication, cataloging, discovery, retrieval, and analysis of hydrologic data using web services. The CUAHSI HIS is an Internet based system comprised of hydrologic databases and servers connected through web services as well as software for data publication, discovery and access. The HIS metadata catalog lists close to 100 web services registered to provide data through this system, ranging from large federal agency data sets to experimental watersheds managed by University investigators. The system's flexibility in storing and enabling public access to similarly formatted data and metadata has created a community data resource from governmental and academic data that might otherwise remain private or analyzed only in isolation. Comprehensive understanding of hydrology requires integration of this information from multiple sources. HydroDesktop is the client application developed as part of HIS to support data discovery and access through this system. HydroDesktop is founded on an open source GIS client and has a plug-in architecture that has enabled the integration of modeling and analysis capability with the functionality for data discovery and access. Model integration is possible through a plug-in built on the OpenMI standard and data visualization and analysis is supported by an R plug-in. This presentation will demonstrate HydroDesktop, showing how it provides an analysis environment within which data from multiple sources can be discovered, accessed and integrated.

Miniature electrical connector

DOEpatents

Casper, Robert F.

1976-01-01

A miniature coaxial cable electrical connector includes an annular compressible gasket in a receptacle member, the gasket having a generally triangular cross section resiliently engaging and encircling a conically tapered outer surface of a plug member to create an elongated current leakage path at their interface; means for preventing rotation of the plug relative to the receptacle; a metal sleeve forming a portion of the receptacle and encircling the plug member when interconnected; and a split ring in the plug having outwardly and rearwardly projecting fingers spaced from and encircling a portion of a coaxial cable and engageable with the metal sleeve to interlock the receptacle and plug.

Partial wetting gas-liquid segmented flow microreactor.

PubMed

Kazemi Oskooei, S Ali; Sinton, David

2010-07-07

A microfluidic reactor strategy for reducing plug-to-plug transport in gas-liquid segmented flow microfluidic reactors is presented. The segmented flow is generated in a wetting portion of the chip that transitions downstream to a partially wetting reaction channel that serves to disconnect the liquid plugs. The resulting residence time distributions show little dependence on channel length, and over 60% narrowing in residence time distribution as compared to an otherwise similar reactor. This partial wetting strategy mitigates a central limitation (plug-to-plug dispersion) while preserving the many attractive features of gas-liquid segmented flow reactors.

Potential role of gas hydrate decomposition in generating submarine slope failures: Chapter 12

USGS Publications Warehouse

Pauli, Charles K.; Ussler, William III; Dillon, William P.; Max, Michael D.

2003-01-01

Gas hydrate decomposition is hypothesized to be a factor in generating weakness in continental margin sediments that may help explain some of the observed patterns of continental margin sediment instability. The processes associated with formation and decomposition of gas hydrate can cause the strengthening of sediments in which gas hydrate grow and the weakening of sediments in which gas hydrate decomposes. The weakened sediments may form horizons along which the potential for sediment failure is increased. While a causal relationship between slope failures and gas hydrate decomposition has not been proven, a number of empirical observations support their potential connection.

Formation of lacustrine plains in west-central Alaska as a result of permafrost degradation and aggradation

NASA Astrophysics Data System (ADS)

Kanevskiy, M. Z.; Jorgenson, M. T.; Shur, Y.; O'Donnell, J.; Harden, J. W.; Fortier, D.

2012-12-01

Perennially frozen lacustrine sediments containing a large amount of ground ice comprise a significant part of the upper permafrost of the lowlands of west-central Alaska, including Koyukuk Flats and Innoko Flats. Study sites are located in the discontinuous permafrost zone, where permafrost was encountered mainly within uplifted peat plateaus. The upper part of studied sections is formed by frozen peat up to 3 m thick underlain by lacustrine silt, which is mostly ice-rich. Cryogenic structure of lacustrine sediments at different sites has common features: (1) prevalence of layered, braided, and reticulate cryostructures; (2) high variability in the ice content of sediments; (3) high density and low water content of soil aggregates separated by ice lenses. Volume of visible ice in silt reaches at places 40% and more. The thickness of ice lenses generally varies from 1 to 5 cm and occasionally reaches 10 cm. Remnants of peat plateaus are surrounded by unfrozen bogs and fens, formed as a result of thawing and settling of ice-rich lacustrine silt. Modern thermokarst scars initially form at places where ice-rich silt is not protected by a thick layer of organic material. Further development of thermokarst bogs includes lateral enlargement of thaw bulbs and collapsing of the margins of peat plateaus. Lacustrine silt within taliks is covered by woody peat accumulated under forests during the stage of permafrost plateau formation and then by aquatic sphagnum peat accumulated in taliks after collapse. We relate the formation of ice-rich lacustrine sediments to development of lake thermokarst, which affected ice-rich silty yedoma deposits during the transition from Pleistocene to Holocene. Terrain development in lacustrine lowlands of west-central Alaska includes five stages related to permafrost aggradation and degradation from the late Pleistocene to the present time: 1) formation of the ice-rich syngenetic permafrost (yedoma) during the late Pleistocene; 2) yedoma degradation in the yearly Holocene and formation of thaw lakes; 3) complete yedoma degradation under thaw lakes and refreezing of thawed sediments at elevated areas; 4) peat accumulation and freezing of sediments in thaw lake basins; and 5) new cycle of thermokarst and formation of taliks under thaw lakes, bogs and fens. Stages of terrain development of lacustrine lowlands since the Late Pleistocene

Punctal occlusion for dry eye syndrome.

PubMed

Ervin, Ann-Margret; Law, Andrew; Pucker, Andrew D

2017-06-26

Dry eye syndrome is a disorder of the tear film that is associated with symptoms of ocular discomfort. Punctal occlusion is a mechanical treatment that blocks the tear drainage system in order to aid in the preservation of natural tears on the ocular surface. To assess the effects of punctal plugs versus no punctal plugs, different types of punctal plugs, and other interventions for managing dry eye. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 11), MEDLINE Ovid (1946 to 8 December 2016), Embase.com (1947 to 8 December 2016), PubMed (1948 to 8 December 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 8 December 2016), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com; last searched 18 November 2012 - this resource is now archived), ClinicalTrials.gov (www.clinicaltrials.gov; searched 8 December 2016), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en; searched 8 December 2016). We did not use any date or language restrictions in the electronic searches for trials. We also searched the Science Citation Index-Expanded database and reference lists of included studies. The evidence was last updated on 8 December 2016 SELECTION CRITERIA: We included randomized and quasi-randomized controlled trials of collagen or silicone punctal plugs in symptomatic participants diagnosed with aqueous tear deficiency or dry eye syndrome. Two review authors independently assessed trial quality and extracted data. We contacted study investigators for additional information when needed. We included 18 trials (711 participants, 1249 eyes) from Austria, Canada, China, Greece, Japan, Mexico, Netherlands, Turkey, the UK, and the USA in this review. We also identified one ongoing trial. Overall we judged these trials to be at unclear risk of bias because they were poorly reported. We assessed the evidence for eight comparisons.Five trials compared punctal plugs with no punctal plugs (control). Three of these trials employed a sham treatment and two trials observed the control group. Two trials did not report outcome data relevant to this review. There was very low-certainty evidence on symptomatic improvement. The three trials that reported this outcome used different scales to measure symptoms. In all three trials, there was little or no improvement in symptom scores with punctal plugs compared with no punctal plugs. Low-certainty evidence from one trial suggested less ocular surface staining in the punctal plug group compared with the no punctal plug group however this difference was small and possibly clinically unimportant (mean difference (MD) in fluorescein staining score -1.50 points, 95% CI -1.88 to -1.12; eyes = 61). Similarly there was a small difference in tear film stability with people in the punctal plug group having more stability (MD 1.93 seconds more, 95% CI 0.67 to 3.20; eyes = 28, low-certainty evidence). The number of artificial tear applications was lower in the punctal plug group compared with the no punctal plugs group in one trial (MD -2.70 applications, 95% CI -3.11 to -2.29; eyes = 61, low-certainty evidence). One trial with low-certainty evidence reported little or no difference between the groups in Schirmer scores, but did not report any quantitative data on aqueous tear production. Very low-certainty evidence on adverse events suggested that events occurred reasonably frequently in the punctal plug group and included epiphora, itching, tenderness and swelling of lids with mucous discharge, and plug displacement.One trial compared punctal plugs with cyclosporine (20 eyes) and one trial compared punctal plugs with oral pilocarpine (55 eyes). The evidence was judged to be very low-certainty due to a combination of risk of bias and imprecision.Five trials compared punctal plugs with artificial tears. In one of the trials punctal plugs was combined with artificial tears and compared with artificial tears alone. There was very low-certainty evidence on symptomatic improvement. Low-certainty evidence of little or no improvement in ocular surface staining comparing punctal plugs with artificial tears (MD right eye 0.10 points higher, 0.56 lower to 0.76 higher, MD left eye 0.60 points higher, 0.10 to 1.10 higher) and low-certainty evidence of little or no difference in aqueous tear production (MD 0.00 mm/5 min, 0.33 lower to 0.33 higher)Three trials compared punctal plugs in the upper versus the lower puncta, and none of them reported the review outcomes at long-term follow-up. One trial with very low-certainty evidence reported no observed complications, but it was unclear which complications were collected.One trial compared acrylic punctal plugs with silicone punctal plugs and the trial reported outcomes at approximately 11 weeks of follow-up (36 eyes). The evidence was judged to be very low-certainty due to a combination of risk of bias and imprecision.One trial compared intracanalicular punctal plugs with silicone punctal plugs at three months follow-up (57 eyes). The evidence was judged to be very low-certainty due to a combination of risk of bias and imprecision.Finally, two trials with very low-certainty evidence compared collagen punctal plugs versus silicone punctal plugs (98 eyes). The evidence was judged to be very low-certainty due to a combination of risk of bias and imprecision. Although the investigators of the individual trials concluded that punctal plugs are an effective means for treating dry eye signs and symptoms, the evidence in this systematic review suggests that improvements in symptoms and commonly tested dry eye signs are inconclusive. Despite the inclusion of 11 additional trials, the findings of this updated review are consistent with the previous review published in 2010. The type of punctal plug investigated, the type and severity of dry eye being treated, and heterogeneity in trial methodology confounds our ability to make decisive statements regarding the effectiveness of punctal plug use. Although punctal plugs are believed to be relatively safe, their use is commonly associated with epiphora and, less commonly, with inflammatory conditions such as dacryocystitis.

Punctal occlusion for dry eye syndrome

PubMed Central

Ervin, Ann-Margret; Law, Andrew; Pucker, Andrew D

2017-01-01

Background Dry eye syndrome is a disorder of the tear film that is associated with symptoms of ocular discomfort. Punctal occlusion is a mechanical treatment that blocks the tear drainage system in order to aid in the preservation of natural tears on the ocular surface. Objectives To assess the effects of punctal plugs versus no punctal plugs, different types of punctal plugs, and other interventions for managing dry eye. Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 11), MEDLINE Ovid (1946 to 8 December 2016), Embase.com (1947 to 8 December 2016), PubMed (1948 to 8 December 2016), LILACS (Latin American and Caribbean Health Sciences Literature Database) (1982 to 8 December 2016), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com; last searched 18 November 2012 - this resource is now archived), ClinicalTrials.gov (www.clinicaltrials.gov; searched 8 December 2016), and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en; searched 8 December 2016). We did not use any date or language restrictions in the electronic searches for trials. We also searched the Science Citation Index-Expanded database and reference lists of included studies. The evidence was last updated on 8 December 2016 Selection criteria We included randomized and quasi-randomized controlled trials of collagen or silicone punctal plugs in symptomatic participants diagnosed with aqueous tear deficiency or dry eye syndrome. Data collection and analysis Two review authors independently assessed trial quality and extracted data. We contacted study investigators for additional information when needed. Main results We included 18 trials (711 participants, 1249 eyes) from Austria, Canada, China, Greece, Japan, Mexico, Netherlands, Turkey, the UK, and the USA in this review. We also identified one ongoing trial. Overall we judged these trials to be at unclear risk of bias because they were poorly reported. We assessed the evidence for eight comparisons. Five trials compared punctal plugs with no punctal plugs (control). Three of these trials employed a sham treatment and two trials observed the control group. Two trials did not report outcome data relevant to this review. There was very low-certainty evidence on symptomatic improvement. The three trials that reported this outcome used different scales to measure symptoms. In all three trials, there was little or no improvement in symptom scores with punctal plugs compared with no punctal plugs. Low-certainty evidence from one trial suggested less ocular surface staining in the punctal plug group compared with the no punctal plug group however this difference was small and possibly clinically unimportant (mean difference (MD) in fluorescein staining score -1.50 points, 95% CI -1.88 to -1.12; eyes = 61). Similarly there was a small difference in tear film stability with people in the punctal plug group having more stability (MD 1.93 seconds more, 95% CI 0.67 to 3.20; eyes = 28, low-certainty evidence). The number of artificial tear applications was lower in the punctal plug group compared with the no punctal plugs group in one trial (MD -2.70 applications, 95% CI -3.11 to -2.29; eyes = 61, low-certainty evidence). One trial with low-certainty evidence reported little or no difference between the groups in Schirmer scores, but did not report any quantitative data on aqueous tear production. Very low-certainty evidence on adverse events suggested that events occurred reasonably frequently in the punctal plug group and included epiphora, itching, tenderness and swelling of lids with mucous discharge, and plug displacement. One trial compared punctal plugs with cyclosporine (20 eyes) and one trial compared punctal plugs with oral pilocarpine (55 eyes). The evidence was judged to be very low-certainty due to a combination of risk of bias and imprecision. Five trials compared punctal plugs with artificial tears. In one of the trials punctal plugs was combined with artificial tears and compared with artificial tears alone. There was very low-certainty evidence on symptomatic improvement. Low-certainty evidence of little or no improvement in ocular surface staining comparing punctal plugs with artificial tears (MD right eye 0.10 points higher, 0.56 lower to 0.76 higher, MD left eye 0.60 points higher, 0.10 to 1.10 higher) and low-certainty evidence of little or no difference in aqueous tear production (MD 0.00 mm/5 min, 0.33 lower to 0.33 higher) Three trials compared punctal plugs in the upper versus the lower puncta, and none of them reported the review outcomes at long-term follow-up. One trial with very low-certainty evidence reported no observed complications, but it was unclear which complications were collected. One trial compared acrylic punctal plugs with silicone punctal plugs and the trial reported outcomes at approximately 11 weeks of follow-up (36 eyes). The evidence was judged to be very low-certainty due to a combination of risk of bias and imprecision. One trial compared intracanalicular punctal plugs with silicone punctal plugs at three months follow-up (57 eyes). The evidence was judged to be very low-certainty due to a combination of risk of bias and imprecision. Finally, two trials with very low-certainty evidence compared collagen punctal plugs versus silicone punctal plugs (98 eyes). The evidence was judged to be very low-certainty due to a combination of risk of bias and imprecision. Authors' conclusions Although the investigators of the individual trials concluded that punctal plugs are an effective means for treating dry eye signs and symptoms, the evidence in this systematic review suggests that improvements in symptoms and commonly tested dry eye signs are inconclusive. Despite the inclusion of 11 additional trials, the findings of this updated review are consistent with the previous review published in 2010. The type of punctal plug investigated, the type and severity of dry eye being treated, and heterogeneity in trial methodology confounds our ability to make decisive statements regarding the effectiveness of punctal plug use. Although punctal plugs are believed to be relatively safe, their use is commonly associated with epiphora and, less commonly, with inflammatory conditions such as dacryocystitis. PMID:28649802

Oligocene Fluvio-Deltaic Depositional Environments Salin Sub-Basin, Central Myanmar

NASA Astrophysics Data System (ADS)

Gough, A.; Hall, R.

2017-12-01

A recent increase in accessibility for research in Myanmar has allowed rapid advancements in the understanding of the geology of the country. Evolving depositional environments can be reconstructed in largely unstudied Oligocene deposits of the Salin sub-basin, of the Central Myanmar Basin. Data has been collected through a fieldwork campaign to target well-exposed sediments along the western margin of the basin. The studied outcrops span approximately one hundred kilometres from north to south, and a series of sedimentary logs, palaeocurrent data, 2D panel diagrams, and samples for petrographical analysis have been collected and interpreted. The Oligocene formations studied include the Shwezetaw, Paduang, and Okhmintaung, each of which show a broadly southwards-trending fluvio-deltaic environment of deposition. Towards the north, the lower Rupelian Shwezetaw Formation comprises thick fluviatile sandstones which grade southwards through macrotidal-dominated fluvio-deltaic interbedded siltstones and rare sandstones, into marine sandstones. Overlying this, the upper Rupelian Paduang Formation grades rapidly from rare fluvial sandstones towards the north of the basin into deltaic and marine interbedded sandstones and siltstones to the south. This formation is more marine in nature, suggesting a minor transgression throughout the lower Oligocene. By the time of deposition of the Okhmintaung Formation in the Chattian the observed deposits solely represent a tidally-influenced deltaic depositional environment, with very little temporal variation, suggesting a stable sea level. Despite the relatively unchanging depositional environment, the formations are approximately 4000 m thick, suggesting that sedimentation kept pace with relatively rapid subsidence. This current study, which will combine depositional environment reconstruction, provenance, and sediment routing analysis, will provide important insights into both the tectonic setting and the huge sediment accumulation of the poorly understood Central Myanmar Basin.

The Tunas Formation (Permian) in the Sierras Australes foldbelt, east central Argentina: evidence for syntectonic sedimentation in a foreland basin

NASA Astrophysics Data System (ADS)

Lopez-Gamundi, O. R.; Conaghan, P. J.; Rossello, E. A.; Cobbold, P. R.

1995-04-01

The Tunas Formation, extensively exposed in the Sierras Australes foldbelt of eastern central Argentina, completes the sedimentation of the Gondwanan (Late Carboniferous-Permian) sequence, locally known as the Pillahuincó Group. The underlying units of the Group show an integrated depositional history which can be explained in terms of glaciomarine sedimentation (Sauce Grande Formation) and postglacial transgression (Piedra Azul and Bonete Formations). This succession also has a rather uniform quartz-rich, sand-sized composition indicative of a cratonic provenance from the Tandilia Massif to the northeast. Early to Late Permian deformation folded and thrusted the southwestern basin margin (Sierras Australes) and triggered the deposition of a 1,500 m — thick, synorogenic prograding wedge, the Tunas Formation, in the adjacent foreland basin (Sauce Grande or Claromecó Basin). Sandstone detrital modes for the Tunas deposits show moderate to low contents of quartz and abundant lithics, mostly of volcanic and metasedimentary origin. Paleocurrents are consistently from the SW. Tuffs interbedded with sandstones in the upper half of Tunas Formation (Early — early Late? Permian) are interpreted as being derived from volcanic glass-rich tuffs settled in a body of water. Extensive rhyolitic ignimbrites and consanguineous airborne tuffaceous material erupted in the northern Patagonian region during that period. The age constraints and similarities in composition between these volcanics and the tuffaceous horizons present in the Sauce Grande, Parana and Karoo Basins suggest a genetic linkage between these two episodes. The intimate relationship between volcanic activity inboard of the paleo-Pacific margin, deformation in the adjacent orogenic belt and subsidence and sedimentation in the contiguous foreland basin constitutes a common motif in the Sauce Grande and Karoo Basins of southwestern Gondwana.

Sediment infilling and wetland formation dynamics in an active crevasse splay of the Mississippi River delta

USGS Publications Warehouse

Cahoon, Donald R.; White, David A.; Lynch, James C.

2011-01-01

Crevasse splay environments provide a mesocosm for evaluating wetland formation and maintenance processes on a decadal time scale. Site elevation, water levels, vertical accretion, elevation change, shallow subsidence, and plant biomass were measured at five habitats along an elevation gradient to evaluate wetland formation and development in Brant Pass Splay; an active crevasse splay of the Balize delta of the Mississippi River. The processes of vertical development (vertical accretion, elevation change, and shallow subsidence) were measured with the surface elevation table–marker horizon method. There were three distinct stages to the accrual of elevation capital and wetland formation in the splay: sediment infilling, vegetative colonization, and development of a mature wetland community. Accretion, elevation gain, and shallow subsidence all decreased by an order of magnitude from the open water (lowest elevation) to the forest (highest elevation) habitats. Vegetative colonization occurred within the first growing season following emergence of the mud surface. An explosively high rate of below-ground production quickly stabilized the loosely consolidated sub-aerial sediments. After emergent vegetation colonization, vertical development slowed and maintenance of marsh elevation was driven both by sediment trapping by the vegetation and accumulation of plant organic matter in the soil. Continued vertical development and survival of the marsh then depended on the health and productivity of the plant community. The process of delta wetland formation is both complex and nonlinear. Determining the dynamics of wetland formation will help in understanding the processes driving the past building of the delta and in developing models for restoring degraded wetlands in the Mississippi River delta and other deltas around the world.

Glacial Cycles Influence Marine Methane Hydrate Formation

NASA Astrophysics Data System (ADS)

Malinverno, A.; Cook, A. E.; Daigle, H.; Oryan, B.

2018-01-01

Methane hydrates in fine-grained continental slope sediments often occupy isolated depth intervals surrounded by hydrate-free sediments. As they are not connected to deep gas sources, these hydrate deposits have been interpreted as sourced by in situ microbial methane. We investigate here the hypothesis that these isolated hydrate accumulations form preferentially in sediments deposited during Pleistocene glacial lowstands that contain relatively large amounts of labile particulate organic carbon, leading to enhanced microbial methanogenesis. To test this hypothesis, we apply an advection-diffusion-reaction model with a time-dependent organic carbon deposition controlled by glacioeustatic sea level variations. In the model, hydrate forms in sediments with greater organic carbon content deposited during the penultimate glacial cycle ( 120-240 ka). The model predictions match hydrate-bearing intervals detected in three sites drilled on the northern Gulf of Mexico continental slope, supporting the hypothesis of hydrate formation driven by enhanced organic carbon burial during glacial lowstands.

Glacigenic sedimentation pulses triggered post-glacial gas hydrate dissociation.

PubMed

Karstens, Jens; Haflidason, Haflidi; Becker, Lukas W M; Berndt, Christian; Rüpke, Lars; Planke, Sverre; Liebetrau, Volker; Schmidt, Mark; Mienert, Jürgen

2018-02-12

Large amounts of methane are stored in continental margins as gas hydrates. They are stable under high pressure and low, but react sensitively to environmental changes. Bottom water temperature and sea level changes were considered as main contributors to gas hydrate dynamics after the last glaciation. However, here we show with numerical simulations that pulses of increased sedimentation dominantly controlled hydrate stability during the end of the last glaciation offshore mid-Norway. Sedimentation pulses triggered widespread gas hydrate dissociation and explains the formation of ubiquitous blowout pipes in water depths of 600 to 800 m. Maximum gas hydrate dissociation correlates spatially and temporally with the formation or reactivation of pockmarks, which is constrained by radiocarbon dating of Isorropodon nyeggaensis bivalve shells. Our results highlight that rapid changes of sedimentation can have a strong impact on gas hydrate systems affecting fluid flow and gas seepage activity, slope stability and the carbon cycle.

40 CFR 147.3108 - Plugging Class I, II, and III wells.

Code of Federal Regulations, 2014 CFR

2014-07-01

... with a cement plug from there to at least one hundred (100) feet above the top of the disposal or injection zone. (2) A cement plug shall also be set from a point at least fifty (50) feet below the shoe of... cement plug shall extend from a point at least thirty feet below the ground surface to a point five (5...

40 CFR 147.3108 - Plugging Class I, II, and III wells.

Code of Federal Regulations, 2013 CFR

2013-07-01

... with a cement plug from there to at least one hundred (100) feet above the top of the disposal or injection zone. (2) A cement plug shall also be set from a point at least fifty (50) feet below the shoe of... cement plug shall extend from a point at least thirty feet below the ground surface to a point five (5...

40 CFR 147.3108 - Plugging Class I, II, and III wells.

Code of Federal Regulations, 2012 CFR

2012-07-01

... with a cement plug from there to at least one hundred (100) feet above the top of the disposal or injection zone. (2) A cement plug shall also be set from a point at least fifty (50) feet below the shoe of... cement plug shall extend from a point at least thirty feet below the ground surface to a point five (5...

40 CFR 147.3108 - Plugging Class I, II, and III wells.

Code of Federal Regulations, 2011 CFR

2011-07-01

... with a cement plug from there to at least one hundred (100) feet above the top of the disposal or injection zone. (2) A cement plug shall also be set from a point at least fifty (50) feet below the shoe of... cement plug shall extend from a point at least thirty feet below the ground surface to a point five (5...

Plug Load Behavioral Change Demonstration Project

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

Metzger, I.; Kandt, A.; VanGeet, O.

2011-08-01

This report documents the methods and results of a plug load study of the Environmental Protection Agency's Region 8 Headquarters in Denver, Colorado, conducted by the National Renewable Energy Laboratory. The study quantified the effect of mechanical and behavioral change approaches on plug load energy reduction and identified effective ways to reduce plug load energy. Load reduction approaches included automated energy management systems and behavioral change strategies.

40 CFR 147.3108 - Plugging Class I, II, and III wells.

Code of Federal Regulations, 2010 CFR

2010-07-01

... with a cement plug from there to at least one hundred (100) feet above the top of the disposal or injection zone. (2) A cement plug shall also be set from a point at least fifty (50) feet below the shoe of... cement plug shall extend from a point at least thirty feet below the ground surface to a point five (5...

A sediment transport model for incision of gullies on steep topography

Treesearch

Erkan Istanbulluoglu; David G. Tarboton; Robert T. Pack; Charles H. Luce

2003-01-01

We have conducted surveys of gullies that developed in a small, steep watershed in the Idaho Batholith after a severe wildfire followed by intense precipitation. We measured gully length and cross sections to estimate the volumes of sediment loss due to gully formation. These volume estimates are assumed to provide an estimate of sediment transport capacity at each...

Zonation of Microbial Communities by a Hydrothermal Mound in the Atlantis II Deep (the Red Sea).

PubMed

Wang, Yong; Li, Jiang Tao; He, Li Sheng; Yang, Bo; Gao, Zhao Ming; Cao, Hui Luo; Batang, Zenon; Al-Suwailem, Abdulaziz; Qian, Pei-Yuan

2015-01-01

In deep-sea geothermal rift zones, the dispersal of hydrothermal fluids of moderately-high temperatures typically forms subseafloor mounds. Major mineral components of the crust covering the mound are barite and metal sulfides. As a result of the continental rifting along the Red Sea, metalliferous sediments accumulate on the seafloor of the Atlantis II Deep. In the present study, a barite crust was identified in a sediment core from the Atlantis II Deep, indicating the formation of a hydrothermal mound at the sampling site. Here, we examined how such a dense barite crust could affect the local environment and the distribution of microbial inhabitants. Our results demonstrate distinctive features of mineral components and microbial communities in the sediment layers separated by the barite crust. Within the mound, archaea accounted for 65% of the community. In contrast, the sediments above the barite boundary were overwhelmed by bacteria. The composition of microbial communities under the mound was similar to that in the sediments of the nearby Discovery Deep and marine cold seeps. This work reveals the zonation of microbial communities after the formation of the hydrothermal mound in the subsurface sediments of the rift basin.

Zonation of Microbial Communities by a Hydrothermal Mound in the Atlantis II Deep (the Red Sea)

PubMed Central

Wang, Yong; Li, Jiang Tao; He, Li Sheng; Yang, Bo; Gao, Zhao Ming; Cao, Hui Luo; Batang, Zenon; Al-Suwailem, Abdulaziz; Qian, Pei-Yuan

2015-01-01

In deep-sea geothermal rift zones, the dispersal of hydrothermal fluids of moderately-high temperatures typically forms subseafloor mounds. Major mineral components of the crust covering the mound are barite and metal sulfides. As a result of the continental rifting along the Red Sea, metalliferous sediments accumulate on the seafloor of the Atlantis II Deep. In the present study, a barite crust was identified in a sediment core from the Atlantis II Deep, indicating the formation of a hydrothermal mound at the sampling site. Here, we examined how such a dense barite crust could affect the local environment and the distribution of microbial inhabitants. Our results demonstrate distinctive features of mineral components and microbial communities in the sediment layers separated by the barite crust. Within the mound, archaea accounted for 65% of the community. In contrast, the sediments above the barite boundary were overwhelmed by bacteria. The composition of microbial communities under the mound was similar to that in the sediments of the nearby Discovery Deep and marine cold seeps. This work reveals the zonation of microbial communities after the formation of the hydrothermal mound in the subsurface sediments of the rift basin. PMID:26485717

Effects of canal plugging on the vestibuloocular reflex and vestibular nerve discharge during passive and active head rotations.

PubMed

Sadeghi, Soroush G; Goldberg, Jay M; Minor, Lloyd B; Cullen, Kathleen E

2009-11-01

Mechanical occlusion (plugging) of the slender ducts of semicircular canals has been used in the clinic as well as in basic vestibular research. Here, we investigated the effect of canal plugging in two macaque monkeys on the horizontal vestibuloocular reflex (VOR) and the responses of vestibular-nerve afferents during passive head rotations. Afferent responses to active head movements were also studied. The horizontal VOR gain decreased after plugging to <0.1 for frequencies <2 Hz but rose to about 0.6 as frequency was increased to 15 Hz. Afferents innervating plugged horizontal canals had response sensitivities that increased with the frequency of passive rotations from <0.01 (spikes/s)/( degrees/s) at 0.5 Hz to values of about 0.2 and 0.5 (spikes/s)/( degrees/s) at 8 Hz for regular and irregular afferents, respectively (<50% of responses in controls). An increase in phase lead was also noted following plugging in afferent discharge, but not in the VOR. Because the phase discrepancy between the VOR and afferent discharge is much larger than that seen in control animals, this suggests that central adaptation shapes VOR dynamics following plugging. The effect of canal plugging on afferent responses can be modeled as an increase in stiffness and a reduction in the dominant time constant and gain in the transfer function describing canal dynamics. Responses were also evident during active head rotations, consistent with the frequency content of these movements. We conclude that canal plugging in macaques is effective only at frequencies <2 Hz. At higher frequencies, afferents show significant responses, with a nearly 90 degrees phase lead, such that they encode near-rotational acceleration. Our results demonstrate that afferents innervating plugged canals respond robustly during voluntary movements, a finding that has implications for understanding the effects of canal plugging in clinical practice.

Effects of Canal Plugging on the Vestibuloocular Reflex and Vestibular Nerve Discharge During Passive and Active Head Rotations

PubMed Central

Sadeghi, Soroush G.; Goldberg, Jay M.; Minor, Lloyd B.

2009-01-01

Mechanical occlusion (plugging) of the slender ducts of semicircular canals has been used in the clinic as well as in basic vestibular research. Here, we investigated the effect of canal plugging in two macaque monkeys on the horizontal vestibuloocular reflex (VOR) and the responses of vestibular-nerve afferents during passive head rotations. Afferent responses to active head movements were also studied. The horizontal VOR gain decreased after plugging to <0.1 for frequencies <2 Hz but rose to about 0.6 as frequency was increased to 15 Hz. Afferents innervating plugged horizontal canals had response sensitivities that increased with the frequency of passive rotations from <0.01 (spikes/s)/(°/s) at 0.5 Hz to values of about 0.2 and 0.5 (spikes/s)/(°/s) at 8 Hz for regular and irregular afferents, respectively (<50% of responses in controls). An increase in phase lead was also noted following plugging in afferent discharge, but not in the VOR. Because the phase discrepancy between the VOR and afferent discharge is much larger than that seen in control animals, this suggests that central adaptation shapes VOR dynamics following plugging. The effect of canal plugging on afferent responses can be modeled as an increase in stiffness and a reduction in the dominant time constant and gain in the transfer function describing canal dynamics. Responses were also evident during active head rotations, consistent with the frequency content of these movements. We conclude that canal plugging in macaques is effective only at frequencies <2 Hz. At higher frequencies, afferents show significant responses, with a nearly 90° phase lead, such that they encode near-rotational acceleration. Our results demonstrate that afferents innervating plugged canals respond robustly during voluntary movements, a finding that has implications for understanding the effects of canal plugging in clinical practice. PMID:19726724

Isotopic, petrologic and biogeochemical investigations of banded iron-formations

NASA Technical Reports Server (NTRS)

Hayes, J. M.; Kaufman, A. J.; Klein, C.; Studley, S. A.; Baur, M. E.; Walter, M. R.

1986-01-01

It is recognized that the first occurrence of banded iron-formations (BIFs) clearly predates biological oxygenation of the atmosphere-hydrosphere system and that their last occurrences extend beyond plausible dates of pervasive biological oxygenation. For this reason, and because enormous quantities of oxidizing power have been sequestered in them, it is widely thought that these massive, but enigmatic, sediments must encode information about the mechanism and timing of the rise of atmospheric O2. By coupling isotopic analyses of iron-formation carbonates with biogeochemical and petrologic investigations, we are studying (1) the mechanism of initial sedimentation of iron; (2) the role of iron in microbially mediated diagenetic processes in fresh iron-formation sediments; and (3) the logical integration of mechanisms of deposition with observed levels of banding. Thus far, it has been shown that (1) carbonates in BIFs of the Hamersley Group of Western Australia are isotopically inhomogenous; (2) the nature and pattern of isotopic ordering is not consistent with a metamorphic origin for the overall depletion of C-13 observed in the carbonates; (3) if biological, the origin of the C-13 depleted carbonate could be either respiratory or fermentative; (4) iron may have been precipitate d as Fe(3+), then reduced to Fe(2+) within the sediment; and (5) sedimentary biogeochemical systems may have been at least partially closed to mass transport of carbonate species.

The effect of tectonic evolution on lacustrine syn-rift sediment patters in Qikou Sag, Bohaiwan Basin, eastern China

NASA Astrophysics Data System (ADS)

Liao, Y.; Wang, H.; Xu, W.

2013-12-01

Normal fault arrays and associated relay ramps between two overlapping en-echelon normal faults are well known to control the deposition and distribution of sediments in alluvial, fluvial and deltaic systems in rift settings. The influence of transfer zones or relay ramps on sediment routes and dispersal patterns in subaqueous (deeper marine/lacustrine), however, is barely studied and hence less clear. Previous experimental studies indicate that subaqueous relay ramps may act as sediment transportation pathways if certain conditions are available. In this study, we integrate detailed structural and stratigraphic analysis with three-dimensional seismic data and limited well log data from the Qikou Sag to examine the tectonic evolution and the syn-rift sediment patterns response to fault growth and linkage in an active rift setting. Qikou Sag is located at the center of Huanghua Depression, Bohaiwan Basin of eastern China. Structurally, it is a typical continental rift basin characterized by a linked system of two NEE-SWW-striking half-grabens and one E-W-striking graben. Qikou sag is filled with Eocene-Oligocene syn-rift sediments and Miocene to Quaternary post-rift sediments. The Eocene-Oligocene rifting stage can be divided into early rifting period (43-36.5 Ma, the third member and second member of Shahejie Formation, Es3 and Es2), stable rifting period (36.5-29Ma, the first member of Shaehejie Formation, Es1) and fault-depressed diversionary period (29-24.6Ma, the Dongying Formation, Ed). This study focus on the early syn-rift, the third and second member of Shehejie Formation, which is mostly dark-grey mudstone interbedded with fine to coarse-grained sandstone deposited by large-scale turbidity currents in deep-lake. In particular, we use a combination of thickness variability and facies distributions, onlap patterns within a high-resolution sequence stratigraphic framework, integrated with structural geometry, fault activity and subsidence history analysis to investigate the degree of tectonic control on subaqueous sediment transportation and dispersal. Specific attention is paid to deposits close to boundary faults-Gangxi fault, Gangdong fault and Binhai fault and associated relay ramp. Our studies show that significant amount of sediments were deposited on the basin floor close to boundary faults hanging-wall, which were derived from Cangxian uplift and might have originated from channel overspill or flow shedding across the faults. However, minor deposits occurred adjacent to and at the foot of relay ramp, suggesting an influence of these topography features on sediment routing, with the intrabasinal structural high-Beidagang buried hill acting as an additional sediment source. Therefore, the substantial differences between subaerial and subaqueous systems may influence the role of relay ramps in controlling the sediment routes and deposition in Qikou Sag. The attempt to depict subaqueous syn-rift sediment dispersal and relate them with relay ramps is needed to consider the interplay of various factors such as sediment provenience, tectonic activity, ramp geometry, and base level fluctuations in the future investigation.

Trace contaminant concentration affects mineral transformation and pollutant fate in hydroxide-weathered Hanford sediments.

PubMed

Perdrial, Nicolas; Rivera, Nelson; Thompson, Aaron; O'Day, Peggy A; Chorover, Jon

2011-12-15

Prior work has shown that when silicaceous sediments are infused with caustic radioactive waste, contaminant fate is tightly coupled to ensuing mineral weathering reactions. However, the effects of local aqueous geochemical conditions on these reactions are poorly studied. Thus, we varied contaminant concentration and pCO(2) during the weathering of previously uncontaminated Hanford sediments over 6 months and 1 year in a solution of caustic waste (pH 13, high ionic strength). Co-contaminants Sr, Cs and I were added at "low" (Cs/Sr: 10(-5)m; I: 10(-7)m) and "high" (Cs/Sr: 10(-3)m; I: 10(-5)m) concentrations, and headspace was held at atmospheric or undetectable (<10ppmv) CO(2) partial pressure. Solid phase characterization revealed the formation of the zeolite chabazite in "high" samples, whereas feldspathoids, sodalite and cancrinite, were formed preferentially in "low" samples. Sr, Cs and I were sequestered in all reacted sediments. Native calcite dissolution in the CO(2)-free treatment drove the formation of strätlingite (Ca(2)Al(2)SiO(7)·8H(2)O) and diminished availability of Si and Al for feldspathoid formation. Results indicate that pCO(2) and contaminant concentrations strongly affect contaminant speciation in waste-weathered sediments, and are therefore likely to impact reaction product stability under any remediation scenario. Copyright © 2011 Elsevier B.V. All rights reserved.

Iron Oxide Deposition from Aqueous Solution and Iron Formations on Mars

NASA Technical Reports Server (NTRS)

Catling, David; Moore, Jeff

2000-01-01

Iron formations are ancient, laminated chemical sediments containing at least 15 wt% Fe. We discuss possible mechanisms for their formation in aqueous environments on early Mars. Such iron oxide deposits may be detectable today.

The diagnostic performance of leak-plugging automated segmentation versus manual tracing of breast lesions on ultrasound images.

PubMed

Xiong, Hui; Sultan, Laith R; Cary, Theodore W; Schultz, Susan M; Bouzghar, Ghizlane; Sehgal, Chandra M

2017-05-01

To assess the diagnostic performance of a leak-plugging segmentation method that we have developed for delineating breast masses on ultrasound images. Fifty-two biopsy-proven breast lesion images were analyzed by three observers using the leak-plugging and manual segmentation methods. From each segmentation method, grayscale and morphological features were extracted and classified as malignant or benign by logistic regression analysis. The performance of leak-plugging and manual segmentations was compared by: size of the lesion, overlap area ( O a ) between the margins, and area under the ROC curves ( A z ). The lesion size from leak-plugging segmentation correlated closely with that from manual tracing ( R 2 of 0.91). O a was higher for leak plugging, 0.92 ± 0.01 and 0.86 ± 0.06 for benign and malignant masses, respectively, compared to 0.80 ± 0.04 and 0.73 ± 0.02 for manual tracings. Overall O a between leak-plugging and manual segmentations was 0.79 ± 0.14 for benign and 0.73 ± 0.14 for malignant lesions. A z for leak plugging was consistently higher (0.910 ± 0.003) compared to 0.888 ± 0.012 for manual tracings. The coefficient of variation of A z between three observers was 0.29% for leak plugging compared to 1.3% for manual tracings. The diagnostic performance, size measurements, and observer variability for automated leak-plugging segmentations were either comparable to or better than those of manual tracings.

Visualizing astronomy data using VRML

NASA Astrophysics Data System (ADS)

Beeson, Brett; Lancaster, Michael; Barnes, David G.; Bourke, Paul D.; Rixon, Guy T.

2004-09-01

Visualisation is a powerful tool for understanding the large data sets typical of astronomical surveys and can reveal unsuspected relationships and anomalous regions of parameter space which may be difficult to find programatically. Visualisation is a classic information technology for optimising scientific return. We are developing a number of generic on-line visualisation tools as a component of the Australian Virtual Observatory project. The tools will be deployed within the framework of the International Virtual Observatory Alliance (IVOA), and follow agreed-upon standards to make them accessible by other programs and people. We and our IVOA partners plan to utilise new information technologies (such as grid computing and web services) to advance the scientific return of existing and future instrumentation. Here we present a new tool - VOlume - which visualises point data. Visualisation of astronomical data normally requires the local installation of complex software, the downloading of potentially large datasets, and very often time-consuming and tedious data format conversions. VOlume enables the astronomer to visualise data using just a web browser and plug-in. This is achieved using IVOA standards which allow us to pass data between Web Services, Java Servlet Technology and Common Gateway Interface programs. Data from a catalogue server can be streamed in eXtensible Mark-up Language format to a servlet which produces Virtual Reality Modeling Language output. The user selects elements of the catalogue to map to geometry and then visualises the result in a browser plug-in such as Cortona or FreeWRL. Other than requiring an input VOTable format file, VOlume is very general. While its major use will likely be to display and explore astronomical source catalogues, it can easily render other important parameter fields such as the sky and redshift coverage of proposed surveys or the sampling of the visibility plane by a rotation-synthesis interferometer.

Alterations in leucocyte subsets and histomorphology in normal-appearing perilesional skin and early and chronic hidradenitis suppurativa lesions.

PubMed

van der Zee, H H; de Ruiter, L; Boer, J; van den Broecke, D G; den Hollander, J C; Laman, J D; Prens, E P

2012-01-01

Current insight into the histopathological course of events during disease progression in hidradenitis suppurativa (HS) is fragmentary. To identify histological alterations and leucocyte subsets in normal-appearing perilesional skin, and early and chronic HS lesions. In this observational study we examined eight perilesional skin samples, and six early and 10 chronic prototypic HS lesions, as well as skin samples from four healthy donors using in situ immunostaining. Perilesional skin showed mild psoriasiform hyperplasia and follicular plugging as well as a low-grade influx of tryptase-positive mast cells, CD3+ T cells, CD138+ plasma cells and factor XIIIa+ dendritic cells. In early HS lesions, neutrophilic abscess formation and influx of mainly macrophages, monocytes and dendritic cells predominated. In chronic disease, the infiltrate expanded with markedly increased frequencies of CD20+ and CD79a+ B cells and CD138+ plasma cells. As in early lesions, free keratin fibres were detected in the dermis and within giant cells. Single detached keratinocytes and strands of follicular epithelium were observed in the dermis, the latter frequently expressing Ki67, indicative of active proliferation. Psoriasiform hyperplasia, follicular plugging and low-grade leucocytic infiltration are already present in normal-appearing perilesional skin. Keratin fibres in the dermis are associated with clinical disease. Early lesions are characterized by neutrophilic abscess formation and influx of mainly histiocytes, and chronic lesions mainly by expansion of B cells and plasma cells in 'pseudo' follicles. Proliferating strands of follicular epithelium may initiate fistula formation. Mast cells are increased in all stages of HS including perilesional skin. © 2011 The Authors. BJD © 2011 British Association of Dermatologists.

A BMP7 Variant Inhibits Tumor Angiogenesis In Vitro and In Vivo through Direct Modulation of Endothelial Cell Biology.

PubMed

Tate, Courtney M; Mc Entire, Jacquelyn; Pallini, Roberto; Vakana, Eliza; Wyss, Lisa; Blosser, Wayne; Ricci-Vitiani, Lucia; D'Alessandris, Quintino Giorgio; Morgante, Liliana; Giannetti, Stefano; Larocca, Luigi Maria; Todaro, Matilde; Benfante, Antonina; Colorito, Maria Luisa; Stassi, Giorgio; De Maria, Ruggero; Rowlinson, Scott; Stancato, Louis

2015-01-01

Bone morphogenetic proteins (BMPs), members of the TGF-β superfamily, have numerous biological activities including control of growth, differentiation, and vascular development. Using an in vitro co-culture endothelial cord formation assay, we investigated the role of a BMP7 variant (BMP7v) in VEGF, bFGF, and tumor-driven angiogenesis. BMP7v treatment led to disruption of neo-endothelial cord formation and regression of existing VEGF and bFGF cords in vitro. Using a series of tumor cell models capable of driving angiogenesis in vitro, BMP7v treatment completely blocked cord formation. Pre-treatment of endothelial cells with BMP7v significantly reduced their cord forming ability, indicating a direct effect on endothelial cell function. BMP7v activated the canonical SMAD signaling pathway in endothelial cells but targeted gene knockdown using shRNA directed against SMAD4 suggests this pathway is not required to mediate the anti-angiogenic effect. In contrast to SMAD activation, BMP7v selectively decreased ERK and AKT activation, significantly decreased endothelial cell migration and down-regulated expression of critical RTKs involved in VEGF and FGF angiogenic signaling, VEGFR2 and FGFR1 respectively. Importantly, in an in vivo angiogenic plug assay that serves as a measurement of angiogenesis, BMP7v significantly decreased hemoglobin content indicating inhibition of neoangiogenesis. In addition, BMP7v significantly decreased angiogenesis in glioblastoma stem-like cell (GSLC) Matrigel plugs and significantly impaired in vivo growth of a GSLC xenograft with a concomitant reduction in microvessel density. These data support BMP7v as a potent anti-angiogenic molecule that is effective in the context of tumor angiogenesis.

Prioritizing Road Treatments using the Geomorphic Roads Analysis and Inventory Package (GRAIP) to Improve Watershed Conditions in the Wall Creek Watershed, Oregon

NASA Astrophysics Data System (ADS)

Day, K. T.; Black, T.; Clifton, C.; Luce, C.; McCune, S.; Nelson, N.

2010-12-01

Wall Creek, tributary to the North Fork John Day River in eastern Oregon, was identified as a priority watershed by the Umatilla National Forest for restoration in 2002. Most streams in this 518 km2 multi-ownership watershed are designated critical habitat for threatened steelhead. Eight streams are listed on the Oregon 303(d) list for elevated temperatures and excess sedimentation. Over 1000 km of public and private roads in the watershed present a major source of potential water quality and habitat impairment. We conducted a watershed-wide inventory of roads using the Geomorphic Roads Analysis and Inventory Package (GRAIP) in 2009 to quantify sediment contributions from roads to streams. GRAIP is a field and GIS-based model developed by the Forest Service Rocky Mountain Research Station and Utah State University that georeferences and quantifies road hydrologic connectivity, sediment production and delivery, mass wasting, and risk of diversion and plugging at stream crossings. Field survey and modeling produced data for 6,473 drainage locations on 726 km of road (most of the publically owned roads) quantifying the location and mass of sediment produced and delivered to streams. Findings indicate a relatively small subset of roads deliver the majority of road-produced fine sediment; 12 percent of the road length delivers 90 percent of the total fine sediment to streams. Overall fine sediment production in the watershed is relatively low (with an estimated background erosion rate of 518,000 kg/yr for the watershed) and sediment produced and delivered from the road system appears to be a modest addition. Road surfaces produce approximately 81,455 kg of fine sediment per year, with 20,976 kg/year delivered to the stream network. Fifty-nine gullies were observed, 41 of which received road runoff. Sixteen road-related landslides were also observed. The excavated volume of these features totals 3,922,000 kg which is equivalent to 175 years of fine sediment delivery at the current rate. These data are being used by the Umatilla National Forest to prioritize road rehabilitation activities including storm risk reduction and road decommissioning, and to move toward an ecologically and economically sustainable road system. The highest sediment-delivering road segments were evaluated in 2010 to prioritize stabilization and storm damage risk reduction projects. Approximately 30 km of hydrologically connected road segments will be proposed for treatments including closure, decommissioning, and stabilization activities. Once complete, these improvements would result in the reduction of about 7,000 kg/year of fine sediment delivered to the fluvial system from the road network, or a third of the total road contribution to stream sedimentation. Methods and results presented are part of federal land management agency involvement in Total Maximum Daily Load development in the John Day Basin. The project is a collaborative effort with funding and support from the Environmental Protection Agency, Bureau of Land Management, and Oregon Department of Environmental Quality.

Dust-tolerant electrical connector

NASA Technical Reports Server (NTRS)

Sadick, Shazad (Inventor); Herman, Jason (Inventor); Roberts, Dustyn (Inventor)

2011-01-01

A connector assembly includes releasably mateable plug and receptacle units. At least one socket is enclosed within the receptacle unit and is aligned with at least one permeable membrane disposed in the front end of the receptacle unit. The plug unit includes a body slidably mounted within a longitudinal bore therein. At least one pin extends from the front end of the body and is aligned with at least one permeable membrane disposed in the front end of the plug unit. The plug unit is biased toward a first, de-mate position in which the body is extended rearwardly such that the pin is enclosed with the plug unit and is slidable to a second, mate position in which the body is compressed forwardly such that the pin projects through the permeable membranes of the plug and receptacle units to electrically connect with the socket.

Self locking drive system for rotating plug of a nuclear reactor

DOEpatents

Brubaker, James E.

1979-01-01

This disclosure describes a self locking drive system for rotating the plugs on the head of a nuclear reactor which is able to restrain plug motion if a seismic event should occur during reactor refueling. A servomotor is engaged via a gear train and a bull gear to the plug. Connected to the gear train is a feedback control system which allows the motor to rotate the plug to predetermined locations for refueling of the reactor. The gear train contains a self locking double enveloping worm gear set. The worm gear set is utilized for its self locking nature to prevent unwanted rotation of the plugs as the result of an earthquake. The double enveloping type is used because its unique contour spreads the load across several teeth providing added strength and allowing the use of a conventional size worm.

Poster: Building a Large Tiled-Display Cluster

DTIC Science & Technology

2012-10-01

graphics cards ( Nvidia Quadro FX 5800), and each graphics ∗e-mail: mark.livingston@nrl.navy.mil †e-mail: jonathan.decker@nrl.navy.mil card in a display...such as DisplayPort and HDMI (see: Nvidia Quadro 6000). We recommend these formats because they are much easier to plug-and-play. 3.4 Leverage Open...will find yourself with all the issues related to owning a server room. Today, there are a number of companies offering turn-key so- lutions for tiled

Geochemical and petrographic data for intrusions peripheral to the Big Timber Stock, Crazy Mountains, Montana

USGS Publications Warehouse

du Bray, Edward A.; Van Gosen, Bradley S.

2015-01-01

The Paleocene Fort Union Formation hosts a compositionally diverse array of Eocene plugs, dikes, and sills arrayed around the Eocene Big Timber stock in the Crazy Mountains of south-central Montana. The geochemistry and petrography of the sills have not previously been characterized or interpreted. The purpose of this report is (1) to present available geochemical and petrographic data for several dozen samples of these rocks and (2) to provide a basic interpretive synthesis of these data.

Stable silicon isotope signatures of marine pore waters - Biogenic opal dissolution versus authigenic clay mineral formation

NASA Astrophysics Data System (ADS)

Ehlert, Claudia; Doering, Kristin; Wallmann, Klaus; Scholz, Florian; Sommer, Stefan; Grasse, Patricia; Geilert, Sonja; Frank, Martin

2016-10-01

Dissolved silicon isotope compositions have been analysed for the first time in pore waters (δ30SiPW) of three short sediment cores from the Peruvian margin upwelling region with distinctly different biogenic opal content in order to investigate silicon isotope fractionation behaviour during early diagenetic turnover of biogenic opal in marine sediments. The δ30SiPW varies between +1.1‰ and +1.9‰ with the highest values occurring in the uppermost part close to the sediment-water interface. These values are of the same order or higher than the δ30Si of the biogenic opal extracted from the same sediments (+0.3‰ to +1.2‰) and of the overlying bottom waters (+1.1‰ to +1.5‰). Together with dissolved silicic acid concentrations well below biogenic opal saturation, our collective observations are consistent with the formation of authigenic alumino-silicates from the dissolving biogenic opal. Using a numerical transport-reaction model we find that approximately 24% of the dissolving biogenic opal is re-precipitated in the sediments in the form of these authigenic phases at a relatively low precipitation rate of 56 μmol Si cm-2 yr-1. The fractionation factor between the precipitates and the pore waters is estimated at -2.0‰. Dissolved and solid cation concentrations further indicate that off Peru, where biogenic opal concentrations in the sediments are high, the availability of reactive terrigenous material is the limiting factor for the formation of authigenic alumino-silicate phases.

PEaCH4 v.2.0: A modelling platform to predict early diagenetic processes in marine sediments with a focus on biogenic methane - Case study: Offshore Namibia

NASA Astrophysics Data System (ADS)

Arning, Esther T.; Häußler, Steffen; van Berk, Wolfgang; Schulz, Hans-Martin

2016-07-01

The modelling of early diagenetic processes in marine sediments is of interest in marine science, and in the oil and gas industry, here, especially with respect to methane occurrence and gas hydrate formation as resources. Early diagenesis in marine sediments evolves from a complex web of intertwining (bio)geochemical reactions. It comprises microbially catalysed reactions and inorganic mineral-water-gas interactions. A model that will describe and consider all of these reactions has to be complex. However, it should be user-friendly, as well as to be applicable for a broad community and not only for experts in the field of marine chemistry. The presented modelling platform PeaCH4 v.2.0 combines both aspects, and is Microsoft Excel©-based. The modelling tool is PHREEQC (version 2), a computer programme for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations. The conceptual PEaCH4 model is based on the conversion of sediment-bound degradable organic matter. PEaCH4 v.2.0 was developed to quantify and predict early diagenetic processes in marine sediments with the focus on biogenic methane formation and its phase behaviour, and allows carbon mass balancing. In regard to the irreversible degradation of organic matter, it comprises a "reaction model" and a "kinetic model" to predict methane formation. Both approaches differ in their calculations and outputs as the "kinetic model" considers the modelling time to integrate temperature dependent biogenic methane formation in its calculations, whereas the "reaction model" simply relies on default organic matter degradation. With regard to the inorganic mineral-water-gas interactions, which are triggered by irreversible degradation of organic matter, PEaCH4 v.2.0 is based on chemical equilibrium thermodynamics, appropriate mass-action laws, and their temperature dependent equilibrium constants. The programme is exemplarily presented with the example of upwelling sediments off Namibia, ODP Leg 175, Site 1082. The application demonstrates that the modelling platform PEaCH4 v.2.0 provides a user-friendly, but complex scientific tool that delivers retraceable information about early diagenetic processes and products in marine sediments.

A Comparative Study of Cycle Variability of Laser Plug Ignition vs Classical Spark Plug Ignition in Combustion Engines

NASA Astrophysics Data System (ADS)

Done, Bogdan

2017-10-01

Over the past 30 years numerous studies and laboratory experiments have researched the use of laser energy to ignite gas and fuel-air mixtures. The actual implementation of this laser application has still to be fully achieved in a commercial automotive application. Laser Plug Ignition as a replacement for Spark Plug Ignition in the internal combustion engines of automotive vehicles, offers several potential benefits such as extending lean burn capability, reducing the cyclic variability between combustion cycles and decreasing the total amount of ignition costs, and implicitly weight and energy requirements. The paper presents preliminary results of cycle variability study carried on a SI Engine equipped with laser Plug Ignition system. Versus classic ignition system, the use of the laser Plug Ignition system assures the reduction of the combustion process variability, reflected in the lower values of the coefficient of variability evaluated for indicated mean effective pressure, maximum pressure, maximum pressure angle and maximum pressure rise rate. The laser plug ignition system was mounted on an experimental spark ignition engine and tested at the regime of 90% load and 2800 rev/min, at dosage of λ=1.1. Compared to conventional spark plug, laser ignition assures the efficiency at lean dosage.

Friction Pull Plug Welding in Aluminum Alloys

NASA Technical Reports Server (NTRS)

Brooke, Shane A.; Bradford, Vann; Burkholder, Jonathon

2011-01-01

NASA fs Marshall Space Flight Center (MSFC) has recently invested much time and effort into the process development of Friction Pull Plug Welding (FPPW). FPPW, is a welding process similar to Friction Push Plug Welding in that, there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part. These two processes differ, in that push plug welding requires an internal reaction support, while pull plug welding reacts to the load externally. FPPW was originally conceived as a post proof repair technique for External Tank. FPPW was easily selected as the primary process used to close out the termination hole on the Constellation Program fs ARES I Upper Stage circumferential Self ] Reacting Friction Stir Welds (SR ]FSW). The versatility of FPPW allows it to also be used as a repair technique for both SR ]FSW and Conventional Friction Stir Welds. To date, all MSFC led development has been concentrated on aluminum alloys (2195, 2219, and 2014). Much work has been done to fully understand and characterize the process fs limitations. A heavy emphasis has been spent on plug design, to match the various weldland thicknesses and alloy combinations. This presentation will summarize these development efforts including weld parameter development, process control, parameter sensitivity studies, plug repair techniques, material properties including tensile, fracture and failure analysis.

Friction Pull Plug Welding in Aluminum Alloys

NASA Technical Reports Server (NTRS)

Brooke, Shane A.; Bradford, Vann

2012-01-01

NASA's Marshall Space Flight Center (MSFC) has recently invested much time and effort into the process development of Friction Pull Plug Welding (FPPW). FPPW, is a welding process similar to Friction Push Plug Welding in that, there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part. These two processes differ, in that push plug welding requires an internal reaction support, while pull plug welding reacts to the load externally. FPPW was originally conceived as a post proof repair technique for the Space Shuttle fs External Tank. FPPW was easily selected as the primary weld process used to close out the termination hole on the Constellation Program's ARES I Upper Stage circumferential Self-Reacting Friction Stir Welds (SR-FSW). The versatility of FPPW allows it to also be used as a repair technique for both SR-FSW and Conventional Friction Stir Welds. To date, all MSFC led development has been concentrated on aluminum alloys (2195, 2219, and 2014). Much work has been done to fully understand and characterize the process's limitations. A heavy emphasis has been spent on plug design, to match the various weldland thicknesses and alloy combinations. This presentation will summarize these development efforts including weld parameter development, process control, parameter sensitivity studies, plug repair techniques, material properties including tensile, fracture and failure analysis.

Paleo-environments of Late Pliocene to Early Pleistocene Foreland-Basin Deposits in the Western Foothills of South-Central Taiwan

NASA Astrophysics Data System (ADS)

Chiu, Tzu-Hsuan; Tien-Shun Lin, Andrew; Chi, Wen-Rong; Wang, Shih-Wei

2017-04-01

Lithofacies and paleo-environmental analyses of the Pliocene-Pleistocene deposits of Taiwan provide a framework to understand the stratigraphic development of foreland basin to the west of the orogenic belt. In this study, we performed lithofacies analyses and biostratigraphic studies on calcareous nannofossils in two areas in south-central Taiwan, the Jhuoshuei River, and the Hushan Reservoir, respectively. The studied lithostratigraphic units are the Chinshui Shale, the Cholan Formation, and the Toukoshan Formation, in an ascending order, with a total stratigraphic thickness more than 3500 m in central Taiwan. Sixteen lithofacies and four lithofacies associations are identified, pertaining to tide-dominated deltaic systems bordering a shallow marine setting in the foreland basin. A few wide-spread layers of thickly-bedded sandstones featuring ball-and-pillow structures are interpreted as resulting from earthquake shaking (i.e., seismites). In addition, the vertical facies change shows a coarsening and shallowing-upward succession, indicating the gradually filling up of the foreland basin by sediment progradation. The progradation is interpreted to result from westward migrating orogenic belt and an increase in sediment supply. The top 2000-m thick foreland succession (i.e., the uppermost part of the Cholan Formation, and the Toukoshan Formation) is dominantly fluvial deposits with occasional intercalations of shoreface sediments, indicating an extremely rapid and balanced rate of basin subsidence and sediment supply for the past 1.5 Ma. Vertebrate fossils of deer and elephants are identified in the upper Cholan Formation deposited in coastal to fluvial settings. Keywords: Pliocene-Pleistocene Epoch, lithofacies, foreland basin, Taiwan

Roles of Ferrous and Sulfide Ions in the Fromation of Algae—Induced Black Bloom in Hyper Eutrophic Freshwater Lakes in China

NASA Astrophysics Data System (ADS)

Shen, Q.; Gao, Q.; Yu, C.; Zhang, L.; Wang, Z.

2016-12-01

Water column hypoxia is one of the most serious threats from eutrophication to large water bodies. In the past several years, black bloom phenomenon has become a serious ecosystem disaster in some important severe eutrophic lakes in China, which caused not only environment degradation but also drinking water crisis. Black color and offensive odour of the water column are two notorious sensory features. High Fe2+ and ΣH2S (ΣS2-=S2-+HS-+H2S) were typical characteristics of the black bloom water. Analysis of the black substances of the black bloom water using X-ray photoelectron spectroscopy indicated that abundant FeS were included in these particulates. The black color of the black bloom water could be attributed to the formation of FeS in the anoxic/anaerobic water column. Field investigation and laboratory incubation experiment indicated that the formation of black bloom was closely related to the Fe2+ and ΣH2S in surface sediments. The Fe2+ concentration in surface sediment pore water was high and showed a release tendency from the sediment water interface to the overlying water during the formation of black bloom, while the similar trend was found in ΣH2S production at sediment water micro-interface. Both Fe2+ and ΣS2- affected by oxic and redox conditions, respectively, contributed to the formation of black bloom significantly. However, ΣS2- was found to be the limiting factor directly controlling the outbreak of black bloom. Analysis of microbioal community diversity demonstrated that sulfate reducing bacteria (SRB) were abundant in the surface sediment of black bloom, which strongly influenced the production and accumulation of ΣH2S and drove the formation of black bloom.

33 CFR 183.556 - Plugs and fittings.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Manufacturer Requirements § 183.556 Plugs and fittings. (a) A fuel system must not have a fitting for draining fuel. (b) A plug used to service the fuel...

Fast-Acting Valve

NASA Technical Reports Server (NTRS)

Wojciechowski, Bogdan V. (Inventor); Pegg, Robert J. (Inventor)

2003-01-01

A fast-acting valve includes an annular valve seat that defines an annular valve orifice between the edges of the annular valve seat, an annular valve plug sized to cover the valve orifice when the valve is closed, and a valve-plug holder for moving the annular valve plug on and off the annular valve seat. The use of an annular orifice reduces the characteristic distance between the edges of the valve seat. Rather than this distance being equal to the diameter of the orifice, as it is for a conventional circular orifice, the characteristic distance equals the distance between the inner and outer radii (for a circular annulus). The reduced characteristic distance greatly reduces the gap required between the annular valve plug and the annular valve seat for the valve to be fully open, thereby greatly reducing the required stroke and corresponding speed and acceleration of the annular valve plug. The use of a valve-plug holder that is under independent control to move the annular valve plug between its open and closed positions is important for achieving controllable fast operation of the valve.

Are restored side channels sustainable aquatic habitat features? Predicting the potential persistence of side channels as aquatic habitats based on their fine sedimentation dynamics

NASA Astrophysics Data System (ADS)

Riquier, Jérémie; Piégay, Hervé; Lamouroux, Nicolas; Vaudor, Lise

2017-10-01

The restoration of side channels (also referred to as abandoned channels, former channels, floodplain channels, or side arms) is increasingly implemented to improve the ecological integrity of river-floodplain systems. However, the design of side channel restoration projects remains poorly informed by theory or empirical observations despite the increasing number of projects. Moreover, feedback regarding the hydromorphological adjustment of restored channels is rarely documented, making it difficult to predict channel persistence as aquatic habitats. In this study, we analyze the spatial and temporal patterns of fine sediment deposition (< 2 mm) in 16 side channels of the Rhône River, France, restored in 1999-2006 by a combination of dredging and/or partial to full reconnection of their extremities and as a by-product of an increase in minimum flow through the bypassed main channels. We develop prediction tools to assess the persistence of restored channels as aquatic habitats, using between five and seven monitoring surveys per channel (spanning 7-15 years after restoration). Observed channel-averaged sedimentation rates ranged from 0 to 40.3 cm·y- 1 and reached 90.3 cm·y- 1 locally. Some channels exhibited a significant decline of sedimentation rates through time, whereas others maintained rather constant rates. Scouring processes (i.e., self-rejuvenation capacity) were occasionally documented in 15 channels. Six of the 16 studied channels appeared to be self-sustaining. The 10 others accumulated more and more fine sediment deposits after restoration. Parametric modeling of sedimentation rates suggested that among these 10 channels, four have long life-durations (i.e., more than a century), three have intermediate life-durations (i.e., likely between three and nine decades), and three others have short life-durations (i.e., likely between two and five decades). Observed channel-averaged sedimentation rates can be predicted from the frequency and magnitude (i.e., maximum shear stress) of upstream overflow events and the maximum intensity of backflow events (i.e., maximum backflow capacity). These predictors reflect the dominant role of side channel geometry (i.e., morphology of the upstream alluvial plug, slope conditions) in controlling their flooding regime. These models applied successfully to a wide range of channel morphologies and can be used to quantify a priori the likely effects and the sustainability of side channel restoration.

Microbial community and nitrogen cycling shift with snowmelt in high-elevation barren soils of Mount Rainier National Park

NASA Astrophysics Data System (ADS)

Simpson, A.; Zabowski, D.

2015-12-01

Climate change and nutrient deposition have the potential to accelerate soil formation in high-elevation sediments recently exposed by glacier or snow melt. This process has implications not only for ecosystem formation on Earth but for the formation of Earth-like ecosystems on other planets and icy moons. Research into microbial communities shifting from subnival to mesotrophic conditions has mainly focused on changes on respiration and biomass, and is generally limited to one or two well-studied geographical locations. In particular, more information is needed on microbial shifts in snow-covered volcanic sediments, which may prove the closest analog to the most 'habitable' non-terrestrial environments for Earth microorganisms. We sampled in volcanic soil and sediment along gradients of elevation and snowmelt - dry soil, moist soil next to snowpack, and soil underneath snowpack - at the Muir Snowfields at Mount Rainier National Park, in order to investigate changes in carbon and nitrogen compounds, microbial diversity and gene expression. Initial results show a decrease in available ammonium and increase in microbial biomass carbon in exposed sediment with increasing soil moisture, and a sharp decrease in microbial C:N ratios after snowmelt and drying. Available/labile organic carbon and organic nitrogen decrease strongly with elevation, while microbial biomass carbon and nitrogen and mineral nitrogen compounds show no change with elevation. Though gene expression data is needed for confirmation, we hypothesize that these snowfields receive strong wind-borne deposits of carbon and nitrogen but that chemoautotrophic communities under semi-permanent snowpack do not shift to more mesotrophic communities until after exposed sediment has already begun to desiccate, limiting soil formation.

Experimental investigation of cesium mobility in the course of secondary mineral formations in Hanford sediment columns at 50 degrees C.

PubMed

Mashal, Kholoud Y; Cetiner, Ziya S

2010-10-01

Formation of secondary minerals and Cs mobility in Hanford sediments were investigated under conditions similar to the Hanford tank leak in a dynamic flow system at 50 degrees C. The objectives were to (1) examine the nature and locations of secondary mineral phases precipitated in the sediments and (2) quantify the amount of Cs retained by the sediment matrix at 50 degrees C. To this end, Hanford sediments were packed into 10-cm long columns and leached with simulated tank waste consisting of 1.4 M NaOH, 0.125 M NaAlO(2), 3.7 M NaNO(3), and 1.3 x 10(-4) M Cs at 50 degrees C. Compositions of outflow solution were monitored with time for up to 25 days, and the columns were then segmented into four 2.5-cm long layers. The colloidal fraction in these segments was characterized in terms of mineralogy, particle morphology, Cs content, and short-range Al and Si structure. It was observed that cancrinite and sodalite precipitated at 50 degrees C. Approximately 53% Cs was retained in the column treated by the simulated tank waste at this temperature. Cesium retention in the column was lowered in the high ionic strength solution due to competition from Na for the exchange sites. This can be explained by alteration of distribution and number of sorption sites which reduces the selectivity of Cs for Na, and through the formation of cancrinite and sodalite. The formation of hydroxide complexes in highly alkaline solutions could also contribute to relatively poor retention of Cs by hindering ion exchange mechanism.

Geochemistry of recent aragonite-rich sediments in Mediterranean karstic marine lakes: Trace elements as pollution and palaeoredox proxies and indicators of authigenic mineral formation.

PubMed

Sondi, Ivan; Mikac, Nevenka; Vdović, Neda; Ivanić, Maja; Furdek, Martina; Škapin, Srečo D

2017-02-01

This study investigates the geochemical characteristics of recent shallow-water aragonite-rich sediments from the karstic marine lakes located in the pristine environment on the island of Mljet (Adriatic Sea). Different trace elements were used as authigenic mineral formation, palaeoredox and pollution indicators. The distribution and the historical record of trace elements deposition mostly depended on the sedimentological processes associated with the formation of aragonite, early diagenetic processes governed by the prevailing physico-chemical conditions and on the recent anthropogenic activity. This study demonstrated that Sr could be used as a proxy indicating authigenic formation of aragonite in a marine carbonate sedimentological environment. Distribution of the redox sensitive elements Mo, Tl, U and Cd was used to identify changes in redox conditions in the investigated lake system and to determine the geochemical cycle of these elements through environmental changes over the last 100 years. The significant enrichment of these elements and the presence of early formed nanostructured authigenic framboidal pyrite in laminated deeper parts of sediment in Malo Jezero, indicate sporadic events of oxygen-depleted euxinic conditions in the recent past. Concentrations of trace elements were in the range characteristic for non-contaminated marine carbonates. However, the increase in the concentrations of Zn, Cu, Pb, Sn, Bi in the upper-most sediment strata of Veliko Jezero indicates a low level of trace element pollution, resulting from anthropogenic inputs over the last 40 years. The presence of butyltin compounds (BuTs) in the surface sediment of Veliko Jezero additionally indicates the anthropogenic influence in the recent past. Copyright © 2016 Elsevier Ltd. All rights reserved.

Triassic metasediments in the internal Dinarides (Kopaonik area, southern Serbia): stratigraphy, paleogeographic and tectonic significance

NASA Astrophysics Data System (ADS)

Schefer, Senecio; Egli, Daniel; Missoni, Sigrid; Bernoulli, Daniel; Fügenschuh, Bernhard; Gawlick, Hans-Jürgen; Jovanović, Divna; Krystyn, Leopold; Lein, Richard; Schmid, Stefan M.; Sudar, Milan N.

2010-04-01

Strongly deformed and metamorphosed sediments in the Studenica Valley and Kopaonik area in southern Serbia expose the easternmost occurrences of Triassic sediments in the Dinarides. In these areas, Upper Paleozoic terrigenous sediments are overlain by Lower Triassic siliciclastics and limestones and by Anisian shallow-water carbonates. A pronounced facies change to hemipelagic and distal turbiditic, cherty metalimestones (Kopaonik Formation) testifies a Late Anisian drowning of the former shallow-water carbonate shelf. Sedimentation of the Kopaonik Formation was contemporaneous with shallow-water carbonate production on nearby carbonate platforms that were the source areas of diluted turbidity currents reaching the depositional area of this formation. The Kopaonik Formation was dated by conodont faunas as Late Anisian to Norian and possibly extends into the Early Jurassic. It is therefore considered an equivalent of the grey Hallstatt facies of the Eastern Alps, the Western Carpathians, and the Albanides-Hellenides. The coeval carbonate platforms were generally situated in more proximal areas of the Adriatic margin, whereas the distal margin was dominated by hemipelagic/pelagic and distal turbiditic sedimentation, facing the evolving Neotethys Ocean to the east. A similar arrangement of Triassic facies belts can be recognized all along the evolving Meliata-Maliac-Vardar branch of Neotethys, which is in line with a ‘one-ocean-hypothesis’ for the Dinarides: all the ophiolites presently located southwest of the Drina-Ivanjica and Kopaonik thrust sheets are derived from an area to the east, and the Drina-Ivanjica and Kopaonik units emerge in tectonic windows from below this ophiolite nappe. On the base of the Triassic facies distribution we see neither argument for an independent Dinaridic Ocean nor evidence for isolated terranes or blocks.

A method for the division of the conglomerate depositional cycle under Milankovitch cycles

NASA Astrophysics Data System (ADS)

Chen, Panpan; Fang, Nianqiao; Li, Cunlei; Liu, Jianmei

2017-06-01

The conglomerate layer at the upper section of the 4th member of the Shahejie formation ({{{{S}}}4}{{u}}) of the Yongan district at the Donying depression is a well-developed sedimentation of several periods. It lacks stable muddy layers and sophisticated classification of the sedimentation periods and the proportion of sedimentary layering in each period has long been a difficult task for geologists. In addressing this problem, this paper attempts to introduce the theory of climatic cycles driven by astronomical periods from astronomical stratigraphy on the basis of the characteristics of the sedimentation under the turbidity current in the region of study. Through studying the conditions for the formation of the conglomerate layer and the factors of control, we pinpoint the formation of the layer in chronology and differentiate the cycle interface and correlation in the same formation period. Milankovitch analysis is conducted on the sedimentation of the conglomerate layer in the region of study to determine if the stratigraphy cycle of the region is primarily controlled by the eccentricity cycle and calculate MSC1 and MSC2 thicknesses of 189.3 m and 78.05 m, respectively. Milankovitch theory is the primary tool used in the analysis, in conjunction with petrographic analysis. The stratum at the {{{{S}}}4}{{u}} is classified into four IV-grade sequences and 11 V-grade sequences. The information on the dominant cycle frequency is used for wave filtering of the well logs and to determine the significant Milankovitch wave log. With the data from this curve, we may compare the stratigraphy cycle with the characteristics of the standard cycle and classify and compare the sedimentation periods of the conglomerate layers in further detail.

Monitoring the formation of clastic-biogenic varves to improve the quality of paleoclimate reconstructions

NASA Astrophysics Data System (ADS)

Ojala, A.; Kosonen, E.; Weckstrom, J.; Korkonen, S.

2013-12-01

Annually laminated (varved) sediments are excellent archives for studies of past climate and environmental changes, as they allow analysis of the undisturbed 'in-situ' sediment composition and structure with a seasonal-scale resolution. Among those, clastic-biogenic varved lake sediments have been found and investigated in Finland and Sweden during the last decades. An important prerequisite for applying varved sediments in palaeoenvironmental studies is understanding the mechanism of rhythmic sedimentation and the composition of different laminae representing annual sedimentation events. This knowledge is essential for verifying the annual nature of varves, for investigating the main factors controlling seasonal sedimentation, and for the interpretations of past environmental changes. Here, we report detailed information on the seasonal sedimentation of different varve components and palaeolimnological indicators (diatoms, chrysophycaean cysts) in Lake Nautajärvi, Finland, using near-bottom sediment trap monitoring. The monitoring results strongly support previous interpretations of the formation of clastic-biogenic varves in Fennoscandian lakes. The results also indicate that seasonal sediment fluxes correspond with regional climate and environmental changes. They clearly reveal differences in the amount of seasonal sediment flux between two climatologically and hydrologically different years. For example, higher snow storage in winter and the discharge intensity during the following spring snow melt clearly increases the suspended sediment load, transportation, and net accumulation of detrital mineral matter during spring and early summer. A prolonged autumn and subsequent freezing and thawing cycles in winter, conversely, results in an incremental but slow accumulation of assorted mineral matter and organic particles during winter, whereas the subsequent spring flooding and detrital sediment yield are diminished and thinner clastic laminae are formed. The accumulation rates of diatoms and chrysophyte cysts suggest these algal groups are more dependent on seasonal processes (e.g. spring and autumnal overturn) than on rapid, short-lived environmental episodes such as the spring discharge peak.

Venera 13 and venera 14: sedimentary rocks on venus?

PubMed

Florensky, C P; Basilevsky, A T; Kryuchkov, V P; Kusmin, R O; Nikolaeva, O V; Pronin, A A; Chernaya, I M; Tyuflin, Y S; Selivanov, A S; Naraeva, M K; Ronca, L B

1983-07-01

Venera 13 and Venera 14 transmitted almost complete panoramic views of their landing sites. Analyses of the photographs show the presence of rock formations undergoing geomorphic degradation. The formations display ripple marks, thin layering, differential erosion, and curvilinear fracturings. Some of them are interpreted as lithified clastic sediments. The lithification could have taken place at depth or at the surface, resulting in a type of duricrust. The origin of the sediments is unknown but could be aeolian, volcanic, or related to impacts or to turbidity currents.

Integration of channel and floodplain suites. I. Developmental sequence and lateral relations of alluvial paleosols.

USGS Publications Warehouse

Bown, T.M.; Kraus, M.J.

1987-01-01

The lower Eocene Willwood Formation of the Bighorn Basin, northwest Wyoming, consists of about 770 m of alluvial rocks that exhibit extensive mechanical and geochemical modifications resulting from Eocene pedogenesis. Five arbitrary stages are proposed to distinguish these soils of different maturities in the Willwood Formation. An inverse relationship exists between soil maturity and short-term sediment accumulation rate. Illustrates several important principles of soil-sediment interrelationships in aggrading alluvial systems that have broad application to other deposits.-from Authors

Spark Plug Defects and Tests

NASA Technical Reports Server (NTRS)

Silsbee, F B; Loeb, L B; Sawyer, L G; Fonseca, E L; Dickinson, H C; Agnew, P G

1920-01-01

The successful operation of the spark plug depends to a large extent on the gas tightness of the plug. Part 1 of this report describes the method used for measuring the gas tightness of aviation spark plugs. Part 2 describes the methods used in testing the electrical conductivity of the insulation material when hot. Part 3 describes the testing of the cold dielectric strength of the insulation material, the resistance to mechanical shock, and the final engine test.

Flow plug with length-to-hole size uniformity for use in flow conditioning and flow metering

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

2012-01-01

A flow plug of varying thickness has a plurality of holes formed therethrough. The plug fits in a conduit such that a fluid flow in the conduit passes through the plug's holes. Each hole is defined by a parameter indicative of size in terms of the cross-sectional area thereof. A ratio of hole length-to-parameter is approximately the same for all of the holes.

Small Intestinal Submucosa Plug for Closure of Dilated Nephrostomy Tracts: A Pilot Study in Swine

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

Kakizawa, Hideyaki; Conlin, M. J.; Pavcnik, Dusan, E-mail: pavcnikd@ohsu.edu

2010-06-15

The aim of this study was to evaluate efficacy of a plug made of small intestinal submucosa (SIS) for closure of dilated nephrostomy tract in the kidney after nephroscopy. Ten kidneys in 5 swine had nephrostomy tracts dilated up to 8 mm. The SIS plug was placed into the dilated renal cortex under nephroscopic control. Follow-up arteriograms, retrograde pyelograms, and macroscopic and histologic studies at 24 h (n = 4), 6 weeks (n = 2), and 3 months (n = 4) were performed to evaluate the efficacy of the plug. The SIS plug effectively closed the dilated nephrostomy tract. Follow-upmore » studies showed minimal changes of the kidneys, except for 1 small infarction, regarding inflammatory and foreign-body reactions and progressive scarring of the SIS. SIS plug is effective for occlusion of dilated nephrostomy tract after nephroscopy. Its efficacy should be compared with other therapeutic options.« less

Pulse-actuated fuel-injection spark plug

DOEpatents

Murray, Ian; Tatro, Clement A.

1978-01-01

A replacement spark plug for reciprocating internal combustion engines that functions as a fuel injector and as a spark plug to provide a "stratified-charge" effect. The conventional carburetor is retained to supply the main fuel-air mixture which may be very lean because of the stratified charge. The replacement plug includes a cylindrical piezoelectric ceramic which contracts to act as a pump whenever an ignition pulse is applied to a central rod through the ceramic. The rod is hollow at its upper end for receiving fuel, it is tapered along its lower length to act as a pump, and it is flattened at its lower end to act as a valve for fuel injection from the pump into the cylinder. The rod also acts as the center electrode of the plug, with the spark jumping from the plug base to the lower end of the rod to thereby provide spark ignition that has inherent proper timing with the fuel injection.

Eddy Current Minimizing Flow Plug for Use in Flow Conditioning and Flow Metering

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor)

2015-01-01

An eddy-current-minimizing flow plug has an outer radial wall with open flow channels formed between the plug's inlet and outlet. The plug has a central region coupled to the inner surface of the outer radial wall. Each open flow channel includes (i) a first portion originating at the inlet and converging to a location in the plug where convergence is contributed to by changes in thickness of the outer radial wall and divergence of the central region, and (ii) a second portion originating in the plug and diverging to the outlet where divergence is contributed to by changes in thickness of the outer radial wall and convergence of the central region. For at least a portion of the open flow channels, a central axis passing through the first and second portions is non-parallel with respect to the given direction of the flow.

SULFIDE MINERALS IN SEDIMENTS

EPA Science Inventory

The formation processes of metal sulfides in sediments, especially iron sulfides, have been the subjects of intense scientific research because of linkages to the global biogeochemical cycles of iron, sulfur, carbon, and oxygen. Transition metal sulfides (e.g., NiS, CuS, ZnS, Cd...

Application of quantitative composite fingerprinting technique to identify the main sediment sources in two small catchments of Iran

NASA Astrophysics Data System (ADS)

Kouhpeima, A.; Feiznia, S.; Ahmadi, H.; Hashemi, S. A.; Zareiee, A. R.

2010-09-01

The targeting of sediment management strategies is a key requirement in developing countries including Iran because of the limited resources available. These targeting is, however hampered by the lack of reliable information on catchment sediment sources. This paper reports the results of using a quantitative composite fingerprinting technique to estimate the relative importance of the primary potential sources within the Amrovan and Royan catchments in Semnan Province, Iran. Fifteen tracers were first selected for tracing and samples were analyzed in the laboratory for these parameters. Statistical methods were applied to the data including nonparametric Kruskal-Wallis test and Differentiation Function Analysis (DFA). For Amrovan catchment three parameters (N, Cr and Co) were found to be not significant in making the discrimination. The optimum fingerprint, comprising Oc, PH, Kaolinite and K was able to distinguish correctly 100% of the source material samples. For the Royan catchment, all of the 15 properties were able to distinguish between the six source types and the optimum fingerprint provided by stepwise DFA (Cholorite, XFD, N and C) correctly classifies 92.9% of the source material samples. The mean contributions from each sediment source obtained by multivariate mixing model varied at two catchments. For Amrovan catchment Upper Red formation is the main sediment sources as this sediment source approximately supplies 36% of the reservoir sediment whereas the dominant sediment source for the Royan catchment is from Karaj formation that supplies 33% of the reservoir sediments. Results indicate that the source fingerprinting approach appears to work well in the study catchments and to generate reliable results.

Holocene deposits in the Mangyshlak Peninsula, North Caspian Sea region

NASA Astrophysics Data System (ADS)

Bezrodnykh, Yu. P.; Deliya, S. V.; Romanyuk, B. F.; Fedorov, V. I.; Sorokin, V. M.; Luksha, V. L.

2014-07-01

Comprehensive analysis of the data of high-precision seismoacoustic profiling, drilling and sampling of deposits using seabed corers, biostratigraphic studies, and radiocarbon age data was performed for the first time for Mangyshlak sediments in several bottom sites of the North Caspian. It was found that the Mangyshlak sediments comprise numerous linearly stretched depressions of 5-10 m in depth (morphologically similar to modern substeppe ilmen areas in the Volga River delta), which are covered by the Novocaspian sedimentary cover, and river incisions (among them the largest Volga River valley). In addition, the Mangyshlak sediments comprise the deltaic alluvial fans of different sizes along the shelf zone of the North Caspian. Analysis of mollusks and biogenic remains indicates that accumulation of the Mangyshlak sediments occurred in freshwater and slightly salty water environments under various hydrodynamic and hydrochemical conditions. According to radiocarbon dating of organic matter, the Mangyshlak sediments formed during sea regression in the range of 10-8 ka (isotopic age) or 11.5-8.5 ka (calendar age). Several types of sediments are distinguished: clayey-carbonate sediments, enriched with organic matter up to the formation of sapropel and peat, accumulated at the lowest sea level; weakly calcareous silty-clayey silts, formed during the subsequent intense filling of paleodepressions with terrigenous material. The features of the mineral composition of sediments are as follows: polymineral composition of clayey material with a high proportion of hydromica and disordered mixed-layered formations, a high content of minerals of the epidote group, amphiboles, and other accessory minerals. All of this indicates a genetic relationship between the Mangyshlak sediments and the Volga terrigenous material.

An observational cohort study on persistency of internal teat sealant residues in milk after calving in dairy cows.

PubMed

Kabera, Fidèle; Dufour, Simon; Keefe, Greg; Roy, Jean-Philippe

2018-04-04

Our objectives were to evaluate the prevalence of quarters with an observable internal teat sealant (ITS) plug at first milking following calving and investigate persistency of ITS residues in milk after calving. An observational cohort study was carried out on 557 quarters of 156 cows treated with ITS in 6 farms in Quebec, Canada. The presence of an ITS plug at first milking and ITS residues in milk at each milking were observed by producers. The effects of various factors on the odds of observing an ITS plug and persistency of ITS residues in milk were studied using generalized logistic mixed and generalized negative binomial mixed models, respectively. Milk samples were taken on the day before dry-off and on 2 occasions after calving for bacterial identification to detect intramammary infection (IMI) using bacteriological culture followed by MALDI-TOF identification. The association between the absence of an ITS plug and the presence of new IMI was assessed using a mixed logistic regression model. Internal teat sealant plugs after calving were more often observed in rear quarters and in quarters receiving ITS alone at drying-off versus antimicrobial and ITS. We observed an average (standard deviation) persistency of 4.0 d (2.3 d). When an ITS plug was still present at first milking (83% of quarters), the elimination of ITS residues in milk after calving was significantly longer (4.5 d, on average) compared with 1.2 d when an ITS plug was absent. In cows with an ITS plug at calving, we observed a higher number of days of excretion in older cows. When a plug could not be observed, rear quarters, older cows, and cows with a long dry period duration excreted ITS residues for a significantly longer period. The lack of a significant association between the absence of a plug and the odds of new IMI at calving suggests that despite the loss of the plug, cows were still protected against new IMI. Although we were able to highlight some statistically significant risk factors explaining persistency of ITS residues following calving, observed differences were often relatively small and, perhaps, not clinically relevant. In conclusion, an ITS plug was present until first milking after calving for 83% quarters, quarters without an ITS plug at first milking appeared to have been protected from new IMI, and ITS residues could be observed in milk up to 12 d in milk. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Experimental investigation of shock-cell noise reduction for dual-stream nozzles in simulated flight

NASA Technical Reports Server (NTRS)

Janardan, B. A.; Yamamoto, K.; Majjigi, R. K.; Brausch, J. F.

1984-01-01

Six scale-model nozzles were tested in an anechoic facility to evauate the effectiveness of convergent-divergent (C-D) terminations in reducing shock-cell noise of unsuppressed and mechanically suppressed coannular plug nozzles. One hundred fifty-three acoustic test points with inverted velocity profiles were conducted under static and simulated flight conditions. Diagnostic flow visualization with a shadowgraph and velocity measurements with a laser velocimeter were performed on selected plumes. Shock-cells were identified on the plug and downstream of the plug of the unsuppressed convergent coannular nozzle with truncated plug. Broadband peak frequencies predicted with the two shock-cell structures were correlated with the observed spectra using the measured shock-cell spacings. Relative to a convergent circular nozzle, the perceived noise level (PNL) data at an observer angle of 60 deg relative to inlet, indicated a reduction of (1) 6.5 dB and 9.2 dB with unsuppressed C-D coannular nozzle with truncated plug and (2) 7.7 dB and 8.3 dB with suppressed C-D coannular nozzle under static and simulated flight conditions, espectively. The unsuppressed C-D coannular nozzle with truncated plug, operating at the C-D design condition, had shock-cells downstream of the plug with no shock-cells on the plug. The downstream shock-cells were eliminated by replacing the truncated plug with a smooth extension to obtain an additional 2.4 dB and 3 dB front quadrant PNL reduction, under static and simulated flight conditions, respectively. Other results are discussed.

Sedimentation pulse in the NE Gulf of Mexico following the 2010 DWH blowout

DOE PAGES

Brooks, Gregg R.; Larson, Rebekka A.; Schwing, Patrick T.; ...

2015-07-14

The objective of this study was to investigate the impacts of the Deepwater Horizon (DWH) oil discharge at the seafloor as recorded in bottom sediments of the DeSoto Canyon region in the northeastern Gulf of Mexico. Through a close coupling of sedimentological, geochemical, and biological approaches, multiple independent lines of evidence from 11 sites sampled in November/December 2010 revealed that the upper ~1 cm depth interval is distinct from underlying sediments and results indicate that particles originated at the sea surface. Consistent dissimilarities in grain size over the surficial ~1 cm of sediments correspond to excess 234Th depths, which indicatesmore » a lack of vertical mixing (bioturbation), suggesting the entire layer was deposited within a 4–5 month period. In addition, a time series from four deep-sea sites sampled up to three additional times over the following two years revealed that excess 234Th depths, accumulation rates, and 234Th inventories decreased rapidly, within a few to several months after initial coring. The interpretation of a rapid sedimentation pulse is corroborated by stratification in solid phase Mn, which is linked to diagenesis and redox change, and the dramatic decrease in benthic formanifera density that was recorded in surficial sediments. Results are consistent with a brief depositional pulse that was also reported in previous studies of sediments, and marine snow formation in surface waters closer to the wellhead during the summer and fall of 2010. Although sediment input from the Mississippi River and advective transport may influence sedimentation on the seafloor in the DeSoto Canyon region, we conclude based on multidisciplinary evidence that the sedimentation pulse in late 2010 is the product of marine snow formation and is likely linked to the DWH discharge.« less

Sedimentation Pulse in the NE Gulf of Mexico following the 2010 DWH Blowout

PubMed Central

Brooks, Gregg R.; Larson, Rebekka A.; Schwing, Patrick T.; Romero, Isabel; Moore, Christopher; Reichart, Gert-Jan; Jilbert, Tom; Chanton, Jeff P.; Hastings, David W.; Overholt, Will A.; Marks, Kala P.; Kostka, Joel E.; Holmes, Charles W.; Hollander, David

2015-01-01

The objective of this study was to investigate the impacts of the Deepwater Horizon (DWH) oil discharge at the seafloor as recorded in bottom sediments of the DeSoto Canyon region in the northeastern Gulf of Mexico. Through a close coupling of sedimentological, geochemical, and biological approaches, multiple independent lines of evidence from 11 sites sampled in November/December 2010 revealed that the upper ~1 cm depth interval is distinct from underlying sediments and results indicate that particles originated at the sea surface. Consistent dissimilarities in grain size over the surficial ~1 cm of sediments correspond to excess 234Th depths, which indicates a lack of vertical mixing (bioturbation), suggesting the entire layer was deposited within a 4–5 month period. Further, a time series from four deep-sea sites sampled up to three additional times over the following two years revealed that excess 234Th depths, accumulation rates, and 234Th inventories decreased rapidly, within a few to several months after initial coring. The interpretation of a rapid sedimentation pulse is corroborated by stratification in solid phase Mn, which is linked to diagenesis and redox change, and the dramatic decrease in benthic formanifera density that was recorded in surficial sediments. Results are consistent with a brief depositional pulse that was also reported in previous studies of sediments, and marine snow formation in surface waters closer to the wellhead during the summer and fall of 2010. Although sediment input from the Mississippi River and advective transport may influence sedimentation on the seafloor in the DeSoto Canyon region, we conclude based on multidisciplinary evidence that the sedimentation pulse in late 2010 is the product of marine snow formation and is likely linked to the DWH discharge. PMID:26172639

Dual Spark Plugs For Stratified-Charge Rotary Engine

NASA Technical Reports Server (NTRS)

Abraham, John; Bracco, Frediano V.

1996-01-01

Fuel efficiency of stratified-charge, rotary, internal-combustion engine increased by improved design featuring dual spark plugs. Second spark plug ignites fuel on upstream side of main fuel injector; enabling faster burning and more nearly complete utilization of fuel.

Detrital-zircon fission-track geochronology of the Lower Cenozoic sediments, NW Himalayan foreland basin: Clues for exhumation and denudation of the Himalaya during the India-Asia collision

NASA Astrophysics Data System (ADS)

Jain, A.; Lal, N.; Suelmani, B.; Awasthi, A. K.; Singh, S.; Kumar, R.

2007-12-01

Detrital-zircon fission-track geochronology of the synorogenically-deposited Subathu-Dagshai-Kasauli-Lower Siwalik Formations of the Sub-Himalayan Lower Cenozoic foreland basin reflects progressive effects of the Himalayan tectonometamorphic events on the Proterozoic-Paleozoic source rock as a consequence of the India-Asia collision. The oldest transgressive marine Subathu Formation (57.0-41.5 Ma) contains a very dominant 302.4 ± 21.9 Ma old detrital zircon FT suite with a few determinable 520.0 Ma grains. This old suite was derived by mild erosion of the Zircon Partially Annealed Zone (ZPAZ) of 240-180 oC, which affected the Himalayan Proterozoic basement and its Tethyan sedimentary cover as a consequence of first imprint of the collision. In addition, 50.0 Ma old detrital zircons in this formation were derived possibly from the Indus Tsangpo Suture Zone and the Trans-Himalayan Ladakh Batholith. Sudden source rock changes and unroofing are manifested in the overlying fluvial Dagshai (~30-20 Ma) and Kasauli (20-13 Ma) molassic sediments, which are characterised by dominant 30.0 and 25.0 Ma old youngest zircon FT peaks, respectively. A distinct unconformity spanning for about 10 Myr gets established between the Subathu-Dagshai formations on the basis of detrital- zircon FT ages. Molassic sedimentation since ~30 Ma coincides with the depletion of detritus from the suture zone, and the bulk derivation from the main Higher Himalayan source rock, which has undergone sequentially the UHP-HP-amphibolite facies metamorphism (53-40 Ma) in the extreme north and widespread Eo- and Neo-Himalayan tectonothermal events in the middle. Strength of the Pre-Himalayan Peaks (PHP) >50 Ma in these younger sediments gradually decreases with the intensification of the Himalayan thermal events till the end of the Kasauli sedimentation. Widespread Eo- and Neo-Himalayan metamorphic events (40.0-30.0 and 25.0-15.0 Ma) have almost remobilised the provenance and obliterated most of the evidences of the Pre-Himalayan Peaks in zircon FT ages and appear to be responsible for incoming of the Himalayan (HP) ~30.0 Ma and Young Himalayan Peaks (YHP) of ~15.0 Ma, respectively; the latter appears only between 13.0 and 11.0 Ma sedimentation of the Lower Siwalik Formation. Three distinct metamorphic events get recognised in source area of the Himalayan Metamorphic Belt. Though the Dagshai-Kasauli-Lower Siwalik sequence records uninterrupted fluvial sedimentation since 30 Ma, distinct breaks in zircon FT ages ~5.0-7.0 Myr at the beginning of each formation records pulsative exhumation of the source area in response to the collision between India and Asia.

Bellows sealed plug valve

DOEpatents

Dukas, Jr., Stephen J.

1990-01-01

A bellows sealed plug valve includes a valve body having an inlet passage and an outlet passage, a valve chamber between the inlet and outlet passages. A valve plug has substantially the same shape as the valve chamber and is rotatably disposed therein. A shaft is movable linearly in response to a signal from a valve actuator. A bellows is sealingly disposed between the valve chamber and the valve actuator and means are located between the bellows and the valve plug for converting linear movement of the shaft connected to the valve actuator to rotational movement of the plug. Various means are disclosed including helical thread mechanism, clevis mechanism and rack and pinion mechanism, all for converting linear motion to rotational motion.

Friction plug welding

NASA Technical Reports Server (NTRS)

Takeshita, Riki (Inventor); Hibbard, Terry L. (Inventor)

2001-01-01

Friction plug welding (FPW) usage is advantageous for friction stir welding (FSW) hole close-outs and weld repairs in 2195 Al--Cu--Li fusion or friction stir welds. Current fusion welding methods of Al--Cu--Li have produced welds containing varied defects. These areas are found by non-destructive examination both after welding and after proof testing. Current techniques for repairing typically small (<0.25) defects weaken the weldment, rely heavily on welders' skill, and are costly. Friction plug welding repairs increase strength, ductility and resistance to cracking over initial weld quality, without requiring much time or operator skill. Friction plug welding while pulling the plug is advantageous because all hardware for performing the weld can be placed on one side of the workpiece.

Comparison of Physical Properties of Marine and Arctic Gas-Hydrate-Bearing Deposits

NASA Astrophysics Data System (ADS)

Winters, W. J.; Walker, M.; Collett, T. S.; Bryant, S. L.; Novosel, I.; Wilcox-Cline, R.; Bing, J.; Gomes, M. L.

2009-12-01

Gas hydrate (GH) occurs in both marine settings and in arctic environments within a wide variety of sediment types. Grain-size analyses from both environments indicate that intrinsic host-sediment properties have a strong influence on gas-hydrate distribution and morphologic characteristics. Depending on the amount formed or dissociated, gas hydrate can significantly change in situ sediment acoustic, mechanical, and hydraulic properties. The U.S. Geological Survey, in cooperation with the U.S. Dept. of Energy, BP Expl.-Alaska, Nat. GH Prog. of India, Canadian Geological Survey, Int. Ocean Drilling Program, Japan Oil Gas and Metals Nat. Corp., Japan Pet. Expl. Co., Int. Marine Past Global Changes Study (IMAGES) program, and Paleoceanography of the Atlantic and Geochemistry (PAGE) program, determined physical properties from marine and arctic sediments and their relation to the presence of GH. At two arctic sites, the Mount Elbert well on the Alaskan North Slope and the Mallik wells on the Mackenzie Delta, NWT, >10-m thick gas-hydrate-bearing (GHB) sandy deposits are capped by finer-grained sediments that may reduce gas migration. In the Mount Elbert well, average median grain sizes (MGS) for the two thickest GHB deposits are 65 and 60 µm. Finer-grained (average MGS of 9 and 28 µm) sediments have plug permeabilities that are 300 and 14 times smaller than underlying GHB sediment. Average MGS of GHB sediment from the Mallik 2L well is ~ 111 µm, compared to overlying sediment with an average MGS of ~ 32 µm. Gas hydrate morphology in the Gulf of Mexico (GOM) and offshore India is substantially more complex than in the arctic, and is related to pervasive, although not exclusive, finer-grained deposits. Massive, several-cm thick, GH layers were recovered in piston cores in the northern GOM, in sediment with little visible lithologic variability (average MGS ~ 0.8 µm). In wells off the east coast of India, GH was present in sand-rich, fractured clay, and reservoirs with both characteristics. Maximum MGS measured on more than 1200 samples was 46 µm, but the average MGS for 14 wells varied from 5 to 10 µm. At Site 10, in the Krishna-Godavari Basin, GH was observed in several morphologic configurations, including complex high-angle planar and rotational veins, solid nodules, and disseminated, in sediment with average MGS of 5 µm, liquid limits between 70 and 98, and plastic limits between 33 and 49. Sediment in a 692-m deep well drilled off the Andaman Islands sporadically hosted disseminated GH in thin coarser-grained ash beds and ash-rich zones. Average and maximum MGS in this well is 6 and 17 µm, respectively. To date, sandy GH reservoirs (with some exceptions, e.g., Nankai Trough) are typically associated with the arctic. However, the presence of thick offshore sand-rich GHB reservoirs is the subject of current investigations, such as by the Gulf of Mexico Joint Industry Project (JIP).

Exhaust Nozzles for Supersonic Flight with Turbojet Engines

NASA Technical Reports Server (NTRS)

Shillito, Thomas B.; Hearth, Donald P.; Cortright, Edgar M.

1956-01-01

Good internal performance over a wide range of flight conditions can be obtained with either a plug nozzle or a variable ejector nozzle that can provide a divergent shroud at high pressure ratios. For both the ejector and the plug nozzle, external flow can sometimes cause serious drag losses and, for some plug-nozzle installations, external flow can cause serious internal performance losses. Plug-nozzle cooling and design of the secondary-air-flow systems for ejectors were also considered .

Plug-in nanoliter pneumatic liquid dispenser with nozzle design flexibility

PubMed Central

Choi, In Ho; Kim, Hojin; Lee, Sanghyun; Baek, Seungbum; Kim, Joonwon

2015-01-01

This paper presents a novel plug-in nanoliter liquid dispensing system with a plug-and-play interface for simple and reversible, yet robust integration of the dispenser. A plug-in type dispenser was developed to facilitate assembly and disassembly with an actuating part through efficient modularization. The entire process for assembly and operation of the plug-in dispenser is performed via the plug-and-play interface in less than a minute without loss of dispensing quality. The minimum volume of droplets pneumatically dispensed using the plug-in dispenser was 124 nl with a coefficient of variation of 1.6%. The dispensed volume increased linearly with the nozzle size. Utilizing this linear relationship, two types of multinozzle dispensers consisting of six parallel channels (emerging from an inlet) and six nozzles were developed to demonstrate a novel strategy for volume gradient dispensing at a single operating condition. The droplet volume dispensed from each nozzle also increased linearly with nozzle size, demonstrating that nozzle size is a dominant factor on dispensed volume, even for multinozzle dispensing. Therefore, the proposed plug-in dispenser enables flexible design of nozzles and reversible integration to dispense droplets with different volumes, depending on the application. Furthermore, to demonstrate the practicality of the proposed dispensing system, we developed a pencil-type dispensing system as an alternative to a conventional pipette for rapid and reliable dispensing of minute volume droplets. PMID:26594263

Acidic and basic solutions dissolve protein plugs made of lithostathine complicating choledochal cyst/pancreaticobiliary maljunction.

PubMed

Kaneko, Kenitiro; Ono, Yasuyuki; Tainaka, Takahisa; Sumida, Wataru; Ando, Hisami

2009-07-01

Symptoms of choledochal cysts are caused by protein plugs made of lithostathine, which block the long common channel and increase pancreaticobiliary ductal pressure. Agents that dissolve protein plugs can provide relief from or prevent symptoms. In the present study, drugs reportedly effective for pancreatic and biliary stones were used in dissolution tests. Protein plugs were obtained from choledochal cysts during surgery in two children (5- and 6-year-old girls). Plugs approximately 2 mm in diameter were immersed in citric acid, tartaric acid, dimethadione, bromhexine, dehydrocholic acid, sodium citrate, hydrochloric acid, and sodium hydroxide solutions under observation with a digital microscope. The pH of each solution was measured using a pH meter. Plugs dissolved in citric acid (5.2 mM; pH 2.64), tartaric acid (6.7 mM; pH 2.51), dimethadione (75 mM; pH 3.70), hydrochloric acid (0.5 mM; pH 3.13), and sodium hydroxide (75 mM; pH 12.75) solutions. Plugs did not dissolve in dimethadione (7.5 mM; pH 4.31), bromhexine (0.1%; pH 4.68), dehydrocholic acid (5%; pH 7.45), and sodium citrate (75 mM; pH 7.23) solutions. Protein plugs in choledochal cysts are dissolved in acidic and basic solutions, which may eliminate longitudinal electrostatic interactions of the lithostathine protofibrils.

NASA SLS Booster Nozzle Plug Pieces Fly During Test

NASA Image and Video Library

2016-06-28

On June 28, a test version of the booster that will help power NASA's new rocket, the Space Launch System, fired up at nearly 6,000 degrees Fahrenheit for a successful, two-minute qualification test at Orbital ATK's test facilities in Promontory, Utah. This video shows the booster's nozzle plug intentionally breaking apart. The smoky ring coming off the booster is condensed water vapor created by a pressure difference between the motor gas and normal air. The nozzle plug is an environmental barrier to prevent heat, dust and moisture from getting inside the booster before it ignites. The plug isn't always part of a static test but was included on this one due to changes made to the hardware. The foam on the plug is denser than previous NASA launch vehicles, as the engines are now in the same plane as the boosters. A numbered grid was placed on the exterior of the plug before the test so the pieces retrieved could support plug breakup assessment and reconstruction. Along with video, collecting the pieces helps determine the size and speed of them when they break apart. Nozzle plug pieces were found as far as 1,500 to 2,000 feet away from the booster. This is the last full-scale qualification test for the booster before the first, uncrewed flight of SLS with the Orion spacecraft in 2018.

Plug-in nanoliter pneumatic liquid dispenser with nozzle design flexibility.

PubMed

Choi, In Ho; Kim, Hojin; Lee, Sanghyun; Baek, Seungbum; Kim, Joonwon

2015-11-01

This paper presents a novel plug-in nanoliter liquid dispensing system with a plug-and-play interface for simple and reversible, yet robust integration of the dispenser. A plug-in type dispenser was developed to facilitate assembly and disassembly with an actuating part through efficient modularization. The entire process for assembly and operation of the plug-in dispenser is performed via the plug-and-play interface in less than a minute without loss of dispensing quality. The minimum volume of droplets pneumatically dispensed using the plug-in dispenser was 124 nl with a coefficient of variation of 1.6%. The dispensed volume increased linearly with the nozzle size. Utilizing this linear relationship, two types of multinozzle dispensers consisting of six parallel channels (emerging from an inlet) and six nozzles were developed to demonstrate a novel strategy for volume gradient dispensing at a single operating condition. The droplet volume dispensed from each nozzle also increased linearly with nozzle size, demonstrating that nozzle size is a dominant factor on dispensed volume, even for multinozzle dispensing. Therefore, the proposed plug-in dispenser enables flexible design of nozzles and reversible integration to dispense droplets with different volumes, depending on the application. Furthermore, to demonstrate the practicality of the proposed dispensing system, we developed a pencil-type dispensing system as an alternative to a conventional pipette for rapid and reliable dispensing of minute volume droplets.

New Tertiary stratigraphy for the Florida Keys and southern peninsula of Florida

USGS Publications Warehouse

Cunningham, K.J.; McNeill, D.F.; Guertin, L.A.; Ciesielski, P.F.; Scott, T.M.; De Verteuil, L.

1998-01-01

Seven lithologic formations, ranging in age from Oligocene to Pleistocene, were recently penetrated by core holes in southernmost Florida. From bottom to top, they are the early Oligocene Suwannee Limestone; late-early Oligocene-to-Miocene Arcadia Formation, basal Hawthorn Group; late Miocene Peace River Formation, upper Hawthorn Group; newly proposed late Miocene-to-Pliocene Long Key and Stock Island Formations; and Pleistocene Key Largo and Miami Limestones. The rocks of the Suwannee Limestone form a third-order sequence. Although the entire thickness was not penetrated, 96 m of Suwannee core from one well contains at least 50 vertically stacked, exposure-capped limestone cycles, presumably related to rapid eustatic fluctuations while experiencing tropical to subtropical conditions. The Arcadia Formation is a composite sequence containing four high-frequency sequences composed of multiple vertically stacked carbonate cycles. Most cycles do not show evidence of subaerial exposure and were deposited under more temperate conditions, relative to the Suwannee Limestone. The Arcadia Formation in southernmost Florida is bounded by regional unconformities representing third-order sequence boundaries. Post-Arcadia transgression produced a major backstepping of sediment accumulation above the upper sequence boundary of the Arcadia Formation. The Peace River Formation, composed of diatomaceous mudstones, has been identified only beneath the Florida peninsula and is not present beneath the Florida Keys. Deposition occurred during marine transgressive to high-stand conditions and a local phosphatization event (recorded in northeast Florida). The transgression is possibly related to a global rise in sea level, which resulted in upwelling of relatively cooler, relatively nutrient-rich water masses onto the Florida Platform. It is proposed that the absence of Peace River sediments beneath the Keys is due to sediment bypass of the upper surface of the Arcadia, a result of sediment sweeping by an ancestral Florida current. During late Miocene to Pliocene time in the Florida Keys, siliciclastics of the Long Key Formation and fine-grained carbonates of the Stock Island Formation prograded toward the southern edge of the Florida Platform and downlapped onto the regional unconformity at the top of the Arcadia. Shallow-marine Pleistocene limestones (Key Largo and Miami Limestones), deposited during tropical to subtropical conditions, drape over accretionary successions of the Long Key and Stock Island Formations.

Gastric varices and hepatic encephalopathy: treatment with vascular plug and gelatin sponge-assisted retrograde transvenous obliteration--a primary report.

PubMed

Gwon, Dong Il; Ko, Gi-Young; Yoon, Hyun-Ki; Sung, Kyu-Bo; Kim, Jin Hyoung; Shin, Ji Hoon; Ko, Heung Kyu; Song, Ho-Young

2013-07-01

To evaluate technical safety, clinical safety, and effectiveness of vascular plug-assisted retrograde transvenous obliteration (RTO) for treatment of gastric varices (GV) and hepatic encephalopathy (HE). This retrospective study was approved by the institutional review board; written informed consent was waived. From April 2009 to December 2011, 20 patients (13, GV; seven, HE) who had undergone vascular plug-assisted RTO were retrospectively evaluated. After retrograde transvenous placement of a vascular plug in the left adrenal vein or gastrorenal shunt, subsequent gelatin-sponge embolization of both gastrorenal shunt and GV was performed. Follow-up computed tomography (CT) and upper gastrointestinal tract endoscopy were performed; clinical and laboratory data were collected to evaluate primary (technical success, complications, clinical success) and secondary (change of liver function by using the Child-Pugh score, worsening of esophageal varices) end points. Laboratory data before and after vascular plug-assisted RTO were compared (paired-sample t test). Placement of the vascular plug and subsequent gelatin-sponge embolization were technically successful in all 20 patients, with no procedure-related complications. Follow-up CT within 1 week after vascular plug-assisted RTO showed complete thrombosis of GV and gastrorenal shunts in all patients. Clinical symptoms of HE completely resolved in all seven patients with HE; mean serum NH3 level of 127.4 μmol/L ± 58 (standard deviation) before vascular plug-assisted RTO decreased significantly to 28.1 μmol/L ± 9.8 within 1 week after vascular plug-assisted RTO (P = .002). Eighteen patients who underwent follow-up longer than 2 months showed complete obliteration of GV and gastrorenal shunts at CT and endoscopy. There were no cases of variceal bleeding or HE during mean follow-up of 422 days. Improvement in Child-Pugh score was observed in 12 of 18 (67%) patients 1 month after vascular plug-assisted RTO. Worsening of esophageal varices was observed in four (22%) patients at mean follow-up of 9.4 months. Vascular plug-assisted RTO is technically simple and safe and seems to be clinically effective for treatment of GV and HE.

Parallel Eclipse Project Checkout

NASA Technical Reports Server (NTRS)

Crockett, Thomas M.; Joswig, Joseph C.; Shams, Khawaja S.; Powell, Mark W.; Bachmann, Andrew G.

2011-01-01

Parallel Eclipse Project Checkout (PEPC) is a program written to leverage parallelism and to automate the checkout process of plug-ins created in Eclipse RCP (Rich Client Platform). Eclipse plug-ins can be aggregated in a feature project. This innovation digests a feature description (xml file) and automatically checks out all of the plug-ins listed in the feature. This resolves the issue of manually checking out each plug-in required to work on the project. To minimize the amount of time necessary to checkout the plug-ins, this program makes the plug-in checkouts parallel. After parsing the feature, a request to checkout for each plug-in in the feature has been inserted. These requests are handled by a thread pool with a configurable number of threads. By checking out the plug-ins in parallel, the checkout process is streamlined before getting started on the project. For instance, projects that took 30 minutes to checkout now take less than 5 minutes. The effect is especially clear on a Mac, which has a network monitor displaying the bandwidth use. When running the client from a developer s home, the checkout process now saturates the bandwidth in order to get all the plug-ins checked out as fast as possible. For comparison, a checkout process that ranged from 8-200 Kbps from a developer s home is now able to saturate a pipe of 1.3 Mbps, resulting in significantly faster checkouts. Eclipse IDE (integrated development environment) tries to build a project as soon as it is downloaded. As part of another optimization, this innovation programmatically tells Eclipse to stop building while checkouts are happening, which dramatically reduces lock contention and enables plug-ins to continue downloading until all of them finish. Furthermore, the software re-enables automatic building, and forces Eclipse to do a clean build once it finishes checking out all of the plug-ins. This software is fully generic and does not contain any NASA-specific code. It can be applied to any Eclipse-based repository with a similar structure. It also can apply build parameters and preferences automatically at the end of the checkout.

Experimental Study on Clogging of Fine Particles in Sand Sediments

NASA Astrophysics Data System (ADS)

Hirabayashi, S.

2015-12-01

In the methane hydrate development from the sand sediment beneath the seafloor, it is anticipated that the migrating fine particles may block the pore and consequently reduces the permeability near the production well. Although this phenomenon is known as skin formation, its microscopic mechanism is still unknown. As a part of a Japanese National hydrate research program (MH21, funded by METI), we carried out an experiment on the clogging of fine particles in sand sediments. A transparent core holder was newly developed to directly visualize the behavior of fine particles in the pore of frame sands and formation of skin. It was observed that there seems to be an induction time before the clogging starts to occur. Once clogging occurs, the upstream fine particles cannot move downstream anymore and the skin is formed. It was found that the rate of skin formation is related to the total volume of injected fine particles while the flow velocity has something to do with the length of the induction time.

Annually laminated lake sediments as recorders of flood events: evidence from combining monitoring and calibration

NASA Astrophysics Data System (ADS)

Kämpf, Lucas; Brauer, Achim; Mueller, Philip; Güntner, Andreas; Merz, Bruno

2015-04-01

The relation of changing climate and the occurrence of strong flood events has been controversially debated over the last years. One major limitation in this respect is the temporal extension of instrumental flood time series, rarely exceeding 50-100 years, which is too short to reflect the full range of natural climate variability in a region. Therefore, geoarchives are increasingly explored as natural flood recorders far beyond the range of instrumental flood time series. Annually laminated (varved) lake sediments provide particularly valuable archives since (i) lakes form ideal traps in the landscape continuously recording sediment flux from the catchment and (ii) individual flood events are recorded as detrital layers and can be dated with seasonal precision by varve counting. Despite the great potential of varved lake sediments for reconstructing long flood time series, there are still some confinements with respect to their interpretation due to a lack in understanding processes controlling the formation of detrital layers. For this purpose, we investigated the formation of detrital flood layers in Lake Mondsee (Upper Austria) in great detail by monitoring flood-related sediment flux and comparing detrital layers in sub-recent sediments with river runoff data. Sediment flux at the lake bottom was trapped over a three-year period (2011-2013) at two locations in Lake Mondsee, one located 0.9 km off the main inflow (proximal) and one in a more distal position at a distance of 2.8 km. The monitoring data include 26 floods of different amplitude (max. hourly discharge=10-110 cbm/s) which triggered variable fluxes of catchment sediment to the lake floor (4-760 g/(sqm*d)). The comparison of runoff and sediment data revealed empiric runoff thresholds for triggering significant detrital sediment influx to the proximal (20 cbm/s) and distal lake basin (30 cbm/s) and an exponential relation between runoff amplitude and the amount of deposited sediment. A succession of 20 sub-millimetre to maximum 8 mm thick flood-triggered detrital layers, deposited between 1976 and 2005, was detected in two varved surface sediment cores from the same locations as the sediment traps. Calibration of the detrital layer record with river runoff data revealed empirical thresholds for flood layer deposition. These thresholds are higher than those for trapped sediment flux but, similarly to the trap results, increasing from the proximal (50-60 cbm/s; daily mean=40 cbm/s) to the distal lake basin (80 cbm/s, 2 days>40 cbm/s). Three flood events above the threshold for detrital layer formation in the proximal and one in the distal lake basin were also recorded in the monitoring period. These events resulted in exceptional sediment transfer to the lake of more than 400 g/sqm at both sites, which is therefore interpreted as the minimum sediment amount for producing a visible detrital layer.

Application of fluid-rock reaction studies to in situ recovery from oil sand deposits, Alberta, Canada - I. Aqueous phase results for an experimental-statistical study of water-bitumen-shale reactions

NASA Astrophysics Data System (ADS)

Boon, J. A.; Hitchon, Brian

1983-02-01

In situ recovery operations in oil sand deposits effectively represent man-imposed low to intermediate temperature metamorphism of the sediments in the deposit. In order to evaluate some of the reactions which occur, a factorial experiment was earned out in which a shale from the Lower Cretaceous McMurray Formation in the Athabasca oil sand deposit of Alberta, in the presence or absence of bitumen, was subjected to hydrothermal treatment with aqueous fluids of varying pH and salinity, at two different temperatures, for periods up to 92 hours. The aqueous fluid was analyzed and the analytical data subjected to statistical factor analysis and analysis of variance, which enabled identification of the main processes, namely, cation exchange, the production of two types of colloidal material, and the dissolution of quartz There is also saturation of the aqueous phase by. as yet unidentified, "total organic carbon" and complete conversion and removal of all nitrogen in the shale to the aqueous phase. These reactions have implications with regards to the economics of the in situ recovery process, specifically with respect to the reuse and/or disposal of the produced water and the plugging of the pore space and hence of reduction of permeability between the injection and production wells. As a result of these experiments it is suggested that monitoring of the composition of the produced water from in situ recovery operations in oil sand deposits would be advisable.

What can the microstructure of stones tell us?

PubMed Central

Williams, James C.; Worcester, Elaine; Lingeman, James E.

2016-01-01

How stones are retained within the kidney while small in size is still not fully understood. In this paper we show two examples of how stones are retained during early growth: One is growth on Randall’s (interstitial) plaque, and the other is growth on mineral that has formed as a luminal plug in a terminal collecting duct. These two mechanisms of stone retention during early growth have distinctive morphologic features that can be seen by methods that show the microscopic structure of the stones. Stones growing on Randall’s plaque display an apatite region that is typically not large in size (less than 0.5 mm across) but which usually shows luminal spaces, which are signs of its origin in the connective tissue of the papilla. Stones growing on ductal plugs also show attachment to a piece of apatite, but the apatite regions are typically larger (often >1 mm long and >0.5 mm wide), and they are solid, without spaces running through them. We propose that knowing the mechanisms of stone retention during early stone formation could allow for better treatment of stone diseases. PMID:27913855

How to find the sedimentary archive of fluvial pollution in a bedrock-confined river reach

NASA Astrophysics Data System (ADS)

Elznicova, Jitka; Matys Grygar, Tomas; Kiss, Timea; Lelkova, Tereza; Balogh, Marton; Sikora, Martin

2016-04-01

The Ohre River springs in the Eastern Germany and it is a tributary of the Labe (Elbe) River in Northwest Bohemia. The river received pollution from several sources during the last five centuries. Most of the pollution sources located along the upper and middle reaches, where the depositional and erosional pattern of the river is highly variable. The upper part of the catchment consists of mainly felsic rocks and the river has a broad floodplain. The middle reach and its right-bank tributaries are deeply incised into the Doupovske Hory Mts., which consists of mafic volcanic rocks; whereas the left-bank tributaries are incised into intrusive and metamorphic rocks of the Krusne Hory Mts. (Ore mountains) with several local ore mines (Ag, Pb and U) in particular in around Olovi and Jachymov. Due to the geologic and geomorphologic complexity, deposition of historical sediments in the middle reach has been spatially limited and uneven, and anomalous background concentrations of risk elements are expected. As a consequence, in the middle reach of the Ohre River it is difficult to find a useful sedimentary archive of historical pollution, though it is desired for two main reasons: (1) to decipher the undocumented and poorly described pollution history from the Krusne Hory Mts. and (2) to better understand the retention of pollutants in the transport zones of a confined river system. Based on historical maps we identified a side-bar (35x320 m) in the middle reach of the river near Straz on Ohre and aimed to describe its formation, its recent erosion/deposition history and to evaluate its sedimentary archive value. In the first half of the 19th century it was an island separated from the valley edge by a side channel. Since then there has been no apparent lateral accretion of the bar (its shape has not been changed), but the upstream part of the side channel aggraded by a sediment plug. We evaluated the current bar topography and geomorphology by a detailed field survey, dated the sediments by dendrology and OSL dating, and performed in situ XRF analysis of sediment cores. The data show that the downstream head of the bar is the oldest and most of fine sediments (mostly sand, minor silt) of the bar material have been historically polluted by Pb mining. The sedimentary sequences, most valuable for reconstruction of recent pollution, were found in the side channel where the fill the representing the last ca 150 years pollution history (Hg and U). The body of the bar has been formed earlier. According to our hypothesis the bar originated as a direct consequence of historical mining in the nearby Jachymov Ore Region. The use of lateral fluvial deposits as a sedimentary archive definitely requires intensive application of fluvial geomorphology. Vice versa, pollution patterns will allow delineating areas, in particular the bar bank and inlet to the side channel, where intensive reworking (erosion/redeposition) occurred as documented by the microtopography and woody debris.

Petrography and geochemistry characteristics of the lower Cretaceous Muling Formation from the Laoheishan Basin, Northeast China: implications for provenance and tectonic setting

NASA Astrophysics Data System (ADS)

Song, Yu; Liu, Zhaojun; Meng, Qingtao; Wang, Yimeng; Zheng, Guodong; Xu, Yinbo

2017-06-01

The petrography, mineralogy and geochemistry of sedimentary rocks from the lower Cretaceous Muling Formation (K1ml) in the Laoheishan basin, northeast (NE) China are studied to determine the weathering intensity, provenance and tectonic setting of the source region. Petrographic data indicate the average quartz-feldspar-lithic fragments (QFL) of the sandstone is Q = 63 %, F = 22 %, and L = 15 %. Lithic fragments mainly contain volcanic clasts that derived from surrounding basement. X-ray diffraction (XRD) data reveal abundant clay and detrital minerals (e.g. quartz), as well as minor calcite in the fine-grained sediments. The Hf contents and element concentration ratios such as Al2O3/TiO2, Co/Th, La/Sc, and La/Th are comparable to sediments derived from felsic and intermediate igneous rocks. The strong genetic relationship with the igneous rocks from the northwest and northeast areas provides evidence that the sediments of the Muling Formation (K1ml) in the Laoheishan basin have been derived from this area. The chemical index of alteration (CIA) and index of chemical variability (ICV) reveal an intensive weathering in the source region of the sediments. The multidimensional tectonic discrimination diagrams indicate that the source rocks of K1ml are mainly derived from the collision system. However, they may also comprise sediments derived from the continental rift system. The results are consistent with the geology of the study area.

The mechanism of erythrocyte sedimentation. Part 1: Channeling in sedimenting blood.

PubMed

Pribush, A; Meyerstein, D; Meyerstein, N

2010-01-01

Despite extensive efforts to elucidate the mechanism of erythrocyte sedimentation, the understanding of this mechanism still remains obscure. In attempt to clarify this issue, we studied the effect of hematocrit (Hct) on the complex admittance of quiescent blood measured at different axial positions of the 2 mm x 2 mm cross-section chambers. It was found that after the aggregation process is completed, the admittance reveals delayed changes caused by the formation of cell-free zones within the settling dispersed phase. The delay time (tau(d)) correlates positively with Hct and the distance between the axial position where measurements were performed and the bottom and is unaffected by the gravitational load. These findings and literature reports for colloidal gels suggest that erythrocytes in aggregating media form a network followed by the formation of plasma channels within it. The cell-free zones form initially near the bottom and then propagate toward the top until they reach the plasma/blood interface. These channels increase the permeability of a network and, as a result, accelerate the sedimentation velocity. The energy of the flow field in channels is sufficiently strong to erode their walls. The upward movement of network fragments in channels is manifested by erratic fluctuations of the conductivity. The main conclusion, which may be drawn from the results of this study, is that the phase separation of blood is associated with the formation of plasma channels within the sedimenting dispersed phase.

Multiscale Investigation on Biofilm Distribution and Its Impact on Macroscopic Biogeochemical Reaction Rates: BIOFILM DISTRIBUTION AND RATE SCALING

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

Yan, Zhifeng; Liu, Chongxuan; Liu, Yuanyuan

Biofilms are critical locations for biogeochemical reactions in the subsurface environment. The occurrence and distribution of biofilms at microscale as well as their impacts on macroscopic biogeochemical reaction rates are still poorly understood. This paper investigated the formation and distributions of biofilms in heterogeneous sediments using multiscale models, and evaluated the effects of biofilm heterogeneity on local and macroscopic biogeochemical reaction rates. Sediment pore structures derived from X-ray computed tomography were used to simulate the microscale flow dynamics and biofilm distribution in the sediment column. The response of biofilm formation and distribution to the variations in hydraulic and chemical propertiesmore » was first examined. One representative biofilm distribution was then utilized to evaluate its effects on macroscopic reaction rates using nitrate reduction as an example. The results revealed that microorganisms primarily grew on the surfaces of grains and aggregates near preferential flow paths where both electron donor and acceptor were readily accessible, leading to the heterogeneous distribution of biofilms in the sediments. The heterogeneous biofilm distribution decreased the macroscopic rate of biogeochemical reactions as compared with those in homogeneous cases. Operationally considering the heterogeneous biofilm distribution in macroscopic reactive transport models such as using dual porosity domain concept can significantly improve the prediction of biogeochemical reaction rates. Overall, this study provided important insights into the biofilm formation and distribution in soils and sediments as well as their impacts on the macroscopic manifestation of reaction rates.« less

Multiscale Investigation on Biofilm Distribution and Its Impact on Macroscopic Biogeochemical Reaction Rates

NASA Astrophysics Data System (ADS)

Yan, Zhifeng; Liu, Chongxuan; Liu, Yuanyuan; Bailey, Vanessa L.

2017-11-01

Biofilms are critical locations for biogeochemical reactions in the subsurface environment. The occurrence and distribution of biofilms at microscale as well as their impacts on macroscopic biogeochemical reaction rates are still poorly understood. This paper investigated the formation and distributions of biofilms in heterogeneous sediments using multiscale models and evaluated the effects of biofilm heterogeneity on local and macroscopic biogeochemical reaction rates. Sediment pore structures derived from X-ray computed tomography were used to simulate the microscale flow dynamics and biofilm distribution in the sediment column. The response of biofilm formation and distribution to the variations in hydraulic and chemical properties was first examined. One representative biofilm distribution was then utilized to evaluate its effects on macroscopic reaction rates using nitrate reduction as an example. The results revealed that microorganisms primarily grew on the surfaces of grains and aggregates near preferential flow paths where both electron donor and acceptor were readily accessible, leading to the heterogeneous distribution of biofilms in the sediments. The heterogeneous biofilm distribution decreased the macroscopic rate of biogeochemical reactions as compared with those in homogeneous cases. Operationally considering the heterogeneous biofilm distribution in macroscopic reactive transport models such as using dual porosity domain concept can significantly improve the prediction of biogeochemical reaction rates. Overall, this study provided important insights into the biofilm formation and distribution in soils and sediments as well as their impacts on the macroscopic manifestation of reaction rates.

The cervical mucus plug inhibits, but does not block, the passage of ascending bacteria from the vagina during pregnancy.

PubMed

Hansen, Lea K; Becher, Naja; Bastholm, Sara; Glavind, Julie; Ramsing, Mette; Kim, Chong J; Romero, Roberto; Jensen, Jørgen S; Uldbjerg, Niels

2014-01-01

To evaluate the microbial load and the inflammatory response in the distal and proximal parts of the cervical mucus plug. Experimental research. Twenty women with a normal, singleton pregnancy. Vaginal swabs and specimens from the distal and proximal parts of the cervical mucus plug. Immunohistochemistry, enzyme-linked immunosorbent assay, quantitative polymerase chain reaction and histology. The total bacterial load (16S rDNA) was significantly lower in the cervical mucus plug compared with the vagina (p = 0.001). Among women harboring Ureaplasma parvum, the median genome equivalents/g were 1574 (interquartile range 2526) in the proximal part, 657 (interquartile range 1620) in the distal part and 60,240 (interquartile range 96,386) in the vagina. Histological examinations and quantitative polymerase chain reaction revealed considerable amounts of lactobacilli and inflammatory cells in both parts of the cervical mucus plug. The matrix metalloproteinase-8 concentration was decreased in the proximal part of the plug compared with the distal part (p = 0.08). The cervical mucus plug inhibits, but does not block, the passage of Ureaplasma parvum during its ascending route from the vagina through the cervical canal. © 2013 Nordic Federation of Societies of Obstetrics and Gynecology.

Rapid wetland expansion during European settlement and its implication for marsh survival under modern sediment delivery rates

USGS Publications Warehouse

Kirwan, Matthew L.; Murray, A. Brad; Donnelly, Jeffrey P.; Corbett, D. Reide

2011-01-01

Fluctuations in sea-level rise rates are thought to dominate the formation and evolution of coastal wetlands. Here we demonstrate a contrasting scenario in which land-use-related changes in sediment delivery rates drive the formation of expansive marshland, and vegetation feedbacks maintain their morphology despite recent sediment supply reduction. Stratigraphic analysis and radiocarbon dating in the Plum Island Estuary (Massachusetts, United States) suggest that salt marshes expanded rapidly during the eighteenth and nineteenth centuries due to increased rates of sediment delivery following deforestation associated with European settlement. Numerical modeling coupled with the stratigraphic observations suggests that existing marshland could survive, but not form under the low suspended sediment concentrations observed in the estuary today. These results suggest that many of the expansive marshes that characterize the modern North American coast are metastable relicts of high nineteenth century sediment delivery rates, and that recent observations of degradation may represent a slow return to pre-settlement marsh extent. In contrast to ecosystem management practices in which restoring pre-anthropogenic conditions is seen as a way to increase ecosystem services, our results suggest that widespread efforts to restore valuable coastal wetlands actually prevent some systems from returning to a natural state.

Impact of uranyl-calcium-carbonato complexes on uranium(VI) adsorption to synthetic and natural sediments.

PubMed

Stewart, Brandy D; Mayes, Melanie A; Fendorf, Scott

2010-02-01

Adsorption on soil and sediment solids may decrease aqueous uranium concentrations and limit its propensity for migration in natural and contaminated settings. Uranium adsorption will be controlled in large part by its aqueous speciation, with a particular dependence on the presence of dissolved calcium and carbonate. Here we quantify the impact of uranyl speciation on adsorption to both goethite and sediments from the Hanford Clastic Dike and Oak Ridge Melton Branch Ridgetop formations. Hanford sediments were preconditioned with sodium acetate and acetic acid to remove carbonate grains, and Ca and carbonate were reintroduced at defined levels to provide a range of aqueous uranyl species. U(VI) adsorption is directly linked to UO(2)(2+) speciation, with the extent of retention decreasing with formation of ternary uranyl-calcium-carbonato species. Adsorption isotherms under the conditions studied are linear, and K(d) values decrease from 48 to 17 L kg(-1) for goethite, from 64 to 29 L kg (-1) for Hanford sediments, and from 95 to 51 L kg(-1) for Melton Branch sediments as the Ca concentration increases from 0 to 1 mM at pH 7. Our observations reveal that, in carbonate-bearing waters, neutral to slightly acidic pH values ( approximately 5) and limited dissolved calcium are optimal for uranium adsorption.

Mineralogy and geochemistry of the sediments of the Etosha Pan Region in northern Namibia: a reconstruction of the depositional environment

NASA Astrophysics Data System (ADS)

Buch, M. W.; Rose, D.

1996-04-01

The paper presents the results of mineralogical and chemical analyses of the clay fraction (<2 μm) of samples from boreholes in the Etosha Pan and smaller pans of the Owambo-Pans-Plain in the Etosha National Park, northern Namibia. Four mineral associations can be differentiated within the vertical succession of the profiles in the Etosha Pan: I) analcime/K-feldspar and mica association; II) analcime/K-feldspar and sepiolite (loughlinite) association; III) expandable sheet silicate (saponite/stevensite) association; and IV) calcite and dolomite association. These mineral associations are the expression of the seasonal saline-alkaline to calciferous, saline-alkaline environment of the present Etosha Pan. The sedimentological and pedological descriptions, combined with the results of the mineralogical and chemical analyses, show a clear differentiation of the profiles of the Etosha Pan in: i) disintegrated sedimentary rocks of the Andoni Formation (mineral association I); ii) par-autochthonous sediments (mineral associations I and II); and iii) allochthonous sediments (mineral associations III and IV). Based on this vertical mineralogical differentiation, four sedimentological-mineralogical/ chemical zones are defined for the actual floor of the Etosha Pan. The zonation shows that a thin cover of allochthonous sediments is only present along the southern margin of the Etosha Pan, including Fisher's Pan. The results support the hypothesis that the Etosha Pan is an erosional form rather than a palaeolake. In principle, the zonal configuration of the recent allochthonous and parautochthonous sediments identified on the Etosha Pan provides a small-scale depositional environment model for the formation of the Etosha limestone and sediments of the Andoni Formation during the Oligocene and Miocene. Thus, the findings help to reconstruct the depositional environment of the evolution of the extensive depocentre of the Etosha basin during the Late Tertiary.

Soil and sediments micromorphology: reconstruction of palaeoenvironments, anthropogenic processes, or more recent human impact on ecosystems

NASA Astrophysics Data System (ADS)

Gérard, Martine; Trombino, Luca; Stoops, Georges

2014-05-01

Soils and sediments registered the environmental changes in time and space, but also display components inherited from human activities, both in archaeological and in modern times. Micromorphological investigations carried out on undisturbed samples of soil and sediments by microscopic and ultramicroscopic techniques, correlated with mineralogy, geochemistry or biology, allow us to interpret the processes behind the formation of regoliths, sediments and anthropogenic deposits, from which a relative chronology, specific environmental conditions and/or extent of human impact may be deduced. The traditional optical microscopy observations, carried on the thin section groundmass and pedofeatures, provide clues on the different processes behind soils and sediments genesis (weathering, supergene, low T hydrothermal, anthropogenic) and their impact on ecosystems or on palaeoenvironments. In more recent times, the improvements in electron microscope imaging technology permit to make detailed observations up to the nanoscale, opening a new domain of observations to micromorphologists, both as regard of the micromass and of the thinner pedofeatures. Moreover, the optimisation of the microgeochemical mapping techniques, with spatially resolved chemical, isotopic or mineralogical analyses, is another powerful tool to gain insight in chemical migration fronts: the limit of the original rock fabric disappearance may be bypassed. In order to illustrate micromorphological researches in natural and man-influenced ecosystems, and to combine researches at different scales, several optical and electronic images of soils and sediments groundmass, associated to their microgeochemical characteristics will be presented, with selected examples taken from the climatic record of paleosols, the impact of hydrothermal alteration on saprolites, the neo-formation of minerals related to weathering process evolution, the protosoil formation in natural and human waste deposits, and the forensic scenarios.

Provenance, age, and environment of mid-Wisconsinan slackwater lake sediment in the St. Louis Metro East area, USA

USGS Publications Warehouse

Curry, B. Brandon; Grimley, D.A.

2006-01-01

Valleys tributary to the Mississippi River contain fossiliferous slackwater lake sediment (Equality Formation) deposited in response to aggradation of the Mississippi River valley during the last glaciation. In the St. Louis Metro East area, the lower part of the Equality Formation is primarily laminated, fossiliferous silt and clay deposited from about 44,150 to 24,310 14C yr B.P. The upper Equality Formation is primarily very fine sand to silt deposited from about 21,200 to 17,000 14C yr B.P. Among the four cores that sample this succession in the St. Louis Metro East area, core MNK-3 (38.64EN, 90.01EW) was selected for detailed study. Three sources are distinguished by the following characteristics: (1) gray smectite-quartz-Se-rich, feldspar-poor material of the Des Moines, Wadena, and James lobes; (2) reddish brown kaolinite-Cu-Fe-rich sediment of the Superior and Rainy lobes; and (3) brown illite-dolomite-Sr-rich sediment of the Lake Michigan and Green Bay lobes. The earliest sediments (44,150 to 41,700 14C yr B.P.) were derived from the central and western provenances and are chronocorrelative with the lower Roxana Silt. A hiatus occurred from about 41,700 to 29,030 14C yr B.P. when much of the middle Roxana Silt (Meadow Member) was deposited on adjacent uplands. The youngest sediment includes evidence of heightened activity of the Superior Lobe at about 29,000 14C yr B.P., the Lake Michigan and Green Bay lobes from about 25,000 to 24,000 14C yr B.P., and the Wadena-Des Moines-James lobes at about 21,000 14C yr B.P. ?? 2005 Society. Published by University of Washington. All rights reserved.

Provenance, tectonic setting and age of the sediments of the Upper Disang Formation in the Phek District, Nagaland

NASA Astrophysics Data System (ADS)

Imchen, Watitemsu; Thong, Glenn T.; Pongen, Temjenrenla

2014-07-01

Integrated petrographic and geochemical studies of sandstones, and geochemical studies of shales of turbidites from the Upper Disang Formation, Phek district, Nagaland have been carried out to determine their provenance, weathering conditions and tectonic setting. Paleomagnetic studies were carried out for magnetostratigraphic purposes. Studies indicate that most of these sediments were derived from felsic and mafic sources with minor contribution from low to medium grade metamorphic rocks. Most of the felsic components have been transported from distant sources as evidenced from extensive reworking of grains. The most likely source rocks are the granite/granite gneiss of the Karbi Anglong crystalline complex to the west of the study area. However, the bulk of the sediments have been contributed from nearby basic and ultrabasic sources. This would correspond to the fast rising Naga Ophiolite, which probably emerged above sea level during the Mid-Eocene. Prevailing high temperatures and humid climate caused intense chemical weathering of the source rocks. The sediments from the west were transported great distances by turbidity currents into an easterly deepening basin. Sediments from the nearby east were rapidly dumped on the seafloor causing rapid mixing, leading to textural and chemical immaturity. Paleomagnetic studies endorse published paleontological evidence to indicate that most of the sediments of the Upper Disang Formation were deposited during the Late Eocene. Deposition took place in a westward-migrating accretionary-prism complex in an active-margin setting at the convergence of the Indian and Burma plates. This was a rapidly-closing basin where anoxic conditions prevailed. Towards the end of the Eocene this basin closed completely with the destruction of the Tethyan Ocean.

Fail-Safe Pressure Plug

NASA Technical Reports Server (NTRS)

Svejkovsky, Paul A.

1993-01-01

Protective plug resists slowly built-up pressure or automatically releases itself if pressure rises suddenly. Seals out moisture at pressures ranging from 50 micrometers of mercury to 200 pounds per square inch. Designed to seal throat of 38 Reaction Control Thrusters on Space Shuttle protecting internal components from corrosion. Plug conforms to contour of nozzle throat, where O-ring forms pressure seal. After plug inserted, cover attached by use of cover-fitting assembly. Modified versions useful in protecting engines, pumps, reaction vessels, and other industrial equipment during shipment and maintenance.

Microscopic Evaluation of Friction Plug Welds- Correlation to a Processing Analysis

NASA Technical Reports Server (NTRS)

Rabenberg, Ellen M.; Chen, Poshou; Gorti, Sridhar

2017-01-01

Recently an analysis of dynamic forge load data from the friction plug weld (FPW) process and the corresponding tensile test results showed that good plug welds fit well within an analytically determined processing parameter box. There were, however, some outliers that compromised the predictions. Here the microstructure of the plug weld material is presented in view of the load analysis with the intent of further understanding the FPW process and how it is affected by the grain structure and subsequent mechanical properties.

Local plantar pressure relief in therapeutic footwear: design guidelines from finite element models.

PubMed

Erdemir, Ahmet; Saucerman, Jeffrey J; Lemmon, David; Loppnow, Bryan; Turso, Brie; Ulbrecht, Jan S; Cavanagh, Peter Re

2005-09-01

A major goal of therapeutic footwear in patients with pain or those at risk for skin injury is to relieve focal loading under prominent metatarsal heads. One frequent approach is to place plugs of compliant material into the midsole of the shoe. This study investigated 36 plug designs, a combination of three materials, six geometries, and two placements using a two-dimensional (2D) finite element model. Realistic loading conditions were obtained from plantar pressures (PP) recorded during walking in five subjects who wore control midsoles manufactured using Microcell Puff. Measured peak pressures underneath the second metatarsal head were similar to the results of the control model. PP obtained from simulations with the plugs built into a firm midsole were compared to the simulation results of the control midsole. Large plugs (e.g. 40 mm width), made out of Microcell Puff Lite or Plastazote Medium, placed at peak pressure sites, resulted in highest reductions in peak pressures (18-28%). Smaller plugs benefited from tapering when placed at high pressure areas. Case studies were completed on a healthy male subject and a diabetic female patient to address the efficacy of a plug design favored by our simulations (pressure based placement, 40 x 20 mm, Plastazote Medium). Successful reductions of second metatarsal head pressures were observed with a mediolateral load redistribution that was not represented by our model. 2D computer simulations allowed systematic investigation of plug properties without the need for high volume experimentation on human subjects and established basic guidelines for plug selection. In particular, plugs that are placed based on plantar pressure measurements were proven to be more effective when compared to those positioned according to the projection of the bony landmark on the foot-shoe plantar contact area.

Coil-On-Plug Ignition for Oxygen/Methane Liquid Rocket Engines in Thermal-Vacuum Environments

NASA Technical Reports Server (NTRS)

Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

2017-01-01

A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX)/liquid methane (LCH4) rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/LCH4 propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. A coil-on-plug ignition system has been developed to successfully demonstrate ignition reliability at these conditions while preventing corona discharge issues. The ICPTA uses spark plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp -2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, hot-fire testing at Plum Brook demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/LCH4 propulsion systems in future spacecraft.

Coil-On-Plug Ignition for LOX/Methane Liquid Rocket Engines in Thermal Vacuum Environments

NASA Technical Reports Server (NTRS)

Melcher, John C.; Atwell, Matthew J.; Morehead, Robert L.; Hurlbert, Eric A.; Bugarin, Luz; Chaidez, Mariana

2017-01-01

A coil-on-plug ignition system has been developed and tested for Liquid Oxygen (LOX) / liquid methane rocket engines operating in thermal vacuum conditions. The igniters were developed and tested as part of the Integrated Cryogenic Propulsion Test Article (ICPTA), previously tested as part of the Project Morpheus test vehicle. The ICPTA uses an integrated, pressure-fed, cryogenic LOX/methane propulsion system including a reaction control system (RCS) and a main engine. The ICPTA was tested at NASA Glenn Research Center's Plum Brook Station in the Spacecraft Propulsion Research Facility (B-2) under vacuum and thermal vacuum conditions. In order to successfully demonstrate ignition reliability in the vacuum conditions and eliminate corona discharge issues, a coil-on-plug ignition system has been developed. The ICPTA uses spark-plug ignition for both the main engine igniter and the RCS. The coil-on-plug configuration eliminates the conventional high-voltage spark plug cable by combining the coil and the spark-plug into a single component. Prior to ICPTA testing at Plum Brook, component-level reaction control engine (RCE) and main engine igniter testing was conducted at NASA Johnson Space Center (JSC), which demonstrated successful hot-fire ignition using the coil-on-plug from sea-level ambient conditions down to 10(exp.-2) torr. Integrated vehicle hot-fire testing at JSC demonstrated electrical and command/data system performance. Lastly, Plum Brook testing demonstrated successful ignitions at simulated altitude conditions at 30 torr and cold thermal-vacuum conditions at 6 torr. The test campaign successfully proved that coil-on-plug technology will enable integrated LOX/methane propulsion systems in future spacecraft.

Automated microfluidic platform for studies of carbon dioxide dissolution and solubility in physical solvents.

PubMed

Abolhasani, Milad; Singh, Mayank; Kumacheva, Eugenia; Günther, Axel

2012-05-07

We present an automated microfluidic (MF) approach for the systematic and rapid investigation of carbon dioxide (CO(2)) mass transfer and solubility in physical solvents. Uniformly sized bubbles of CO(2) with lengths exceeding the width of the microchannel (plugs) were isothermally generated in a co-flowing physical solvent within a gas-impermeable, silicon-based MF platform that is compatible with a wide range of solvents, temperatures and pressures. We dynamically determined the volume reduction of the plugs from images that were accommodated within a single field of view, six different downstream locations of the microchannel at any given flow condition. Evaluating plug sizes in real time allowed our automated strategy to suitably select inlet pressures and solvent flow rates such that otherwise dynamically self-selecting parameters (e.g., the plug size, the solvent segment size, and the plug velocity) could be either kept constant or systematically altered. Specifically, if a constant slug length was imposed, the volumetric dissolution rate of CO(2) could be deduced from the measured rate of plug shrinkage. The solubility of CO(2) in the physical solvent was obtained from a comparison between the terminal and the initial plug sizes. Solubility data were acquired every 5 min and were within 2-5% accuracy as compared to literature data. A parameter space consisting of the plug length, solvent slug length and plug velocity at the microchannel inlet was established for different CO(2)-solvent pairs with high and low gas solubilities. In a case study, we selected the gas-liquid pair CO(2)-dimethyl carbonate (DMC) and volumetric mass transfer coefficients 4-30 s(-1) (translating into mass transfer times between 0.25 s and 0.03 s), and Henry's constants, within the range of 6-12 MPa.

Preparation and Evaluation of Biodegradable Scleral Plug Containing Curcumin in Rabbit Eye.

PubMed

Zhang, Jun; Sun, Haiyan; Zhou, Nalei; Zhang, Bin; Ma, Jingxue

2017-12-01

To test whether biodegradable curcumin-loaded scleral plug is a promising choice for treating posterior ocular diseases, the study investigated the in vitro release profile of the scleral plug and its safety in vivo. Scleral plugs containing 0.5 mg, 1.0 mg and 1.5 mg curcumin were synthesized by a compression-sintering method. These scleral plugs were placed in tubes containing balanced salt solution (BSS) buffer, which was replaced by fresh buffer daily. The curcumin concentration in the removed aliquot was tested daily for 14 days using high-performance liquid chromatography (HPLC). In the study, 44 rabbits were randomly divided into four groups: control, 0.5 mg, 1.0 mg and 1.5 mg curcumin groups. The scleral plug was trans-scleral fixed in the right eye of the rabbits in the three curcumin-treated groups. The control rabbits only received sclerotomy. The treated rabbit eyes were examined by a slit-lamp biomicroscope, an indirect ophthalmoscope and electroretinogram (ERG), and subjected to histological analysis. The concentration of the 1.5 mg curcumin-loaded scleral plug was higher than 15 μg/ml for consecutive 14 days in vitro. The in vivo experiments revealed intraocular pressure, a-wave and b-wave amplitudes of ERG, and conjunctival reaction degree were not significantly different between the four groups. Retinal structure was normal in the curcumin-treated groups. The sclerotomy wound healed after the plug was completely degraded. Anterior chamber reaction or complications were not observed. The study suggests that curcumin-loaded scleral plug could sustain high concentration of curcumin in vitro and is safe in vivo. It might be a promising alternative choice for the treatment of posterior ocular diseases.

Punctal plugs versus artificial tears for treating dry eye: a comparative observation of their effects on contrast sensitivity.

PubMed

Qiu, Weiqiang; Liu, Ziyuan; Zhang, Zhihong; Ao, Mingxin; Li, Xuemin; Wang, Wei

2012-01-01

This study aimed to compare the effects of treatment with punctal plugs versus artificial tears on visual function and tear film stability for dry eye. A total of 56 consecutive eyes of 28 dry eye patients observed at our clinic from May to October in 2009 were divided into two groups. One group (32 eyes of 16 patients) was treated with artificial tears, and punctal plugs were used in the other group (24 eyes of 12 patients). A questionnaire was used in these patients before treatment and was repeated 2 weeks after treatment. Fluorescent staining for tear film break-up time (BUT), the Schirmer test I (STI), and contrast sensitivity was performed at the same time. The questionnaire indicated that all patients complained about the uncomfortable symptoms associated with dry eye. These symptoms were relieved after the application of artificial tears or punctal plugs, and there was no significant difference between these two groups. We found that the corneal fluorescent staining disappeared after treatment. The BUT was improved significantly after treatment in both groups, but the improvement was greater in patients who received punctal plugs than those that received artificial tears. There was no remarkable change in the STI in the artificial tears group, but a significant change was observed in the punctal plugs group. The contrast sensitivities were greatly improved in simulated daylight, night, and glare disability conditions after treatment with artificial tears and punctal plugs. However, the changes in contrast sensitivity did not significantly differ between groups. Both artificial tears and punctal plugs relieved dry eye symptoms, repaired corneal lesions, enhanced tear film stability, and improved contrast sensitivity. Punctal plugs could improve tear film stability and elongate the BUT better than artificial tears.

Mineral ecophysiological evidence for microbial activity in banded iron formation

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

Li, Dr. Yi-Liang; Konhauser, Dr, Kurt; Cole, David R

2011-01-01

The phosphorus composition of banded-iron formations (BIFs) has been used as a proxy for Precambrian seawater composition and the paleoeredox state of Earth's surface environment. However, it is unclear whether the phosphorus in BIFs originally entered the sediment as a sorbed component of the iron oxyhydroxide particles, or whether it was incorporated into the biomass of marine phytoplankton. We conducted high-resolution mineral analyses and report here the first detection of an Fe(III) acetate salt, as well as nanocrystals of apatite in association with magnetite, in the 2.48 Ga Dales Gorge Member of the Brockman Iron Formation (a BIF), Hamersley, Westernmore » Australia. The clusters of apatite are similar in size and morphology to biogenic apatite crystals resulting from biomass decay in Phanerozoic marine sediments, while the formation of an Fe(III) acetate salt and magnetite not only implies the original presence of biomass in the BIF sediments, but also that organic carbon likely served as an electron donor during bacterial Fe(III) reduction. This study is important because it suggests that phytoplankton may have played a key role in the transfer of phosphorus (and other trace elements) from the photic zone to the seafloor.« less

Porous plug for reducing orifice induced pressure error in airfoils

NASA Technical Reports Server (NTRS)

Plentovich, Elizabeth B. (Inventor); Gloss, Blair B. (Inventor); Eves, John W. (Inventor); Stack, John P. (Inventor)

1988-01-01

A porous plug is provided for the reduction or elimination of positive error caused by the orifice during static pressure measurements of airfoils. The porous plug is press fitted into the orifice, thereby preventing the error caused either by fluid flow turning into the exposed orifice or by the fluid flow stagnating at the downstream edge of the orifice. In addition, the porous plug is made flush with the outer surface of the airfoil, by filing and polishing, to provide a smooth surface which alleviates the error caused by imperfections in the orifice. The porous plug is preferably made of sintered metal, which allows air to pass through the pores, so that the static pressure measurements can be made by remote transducers.

System and method for charging a plug-in electric vehicle

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

Bassham, Marjorie A.; Spigno, Jr., Ciro A.; Muller, Brett T.

2017-05-02

A charging system and method that may be used to automatically apply customized charging settings to a plug-in electric vehicle, where application of the settings is based on the vehicle's location. According to an exemplary embodiment, a user may establish and save a separate charging profile with certain customized charging settings for each geographic location where they plan to charge their plug-in electric vehicle. Whenever the plug-in electric vehicle enters a new geographic area, the charging method may automatically apply the charging profile that corresponds to that area. Thus, the user does not have to manually change or manipulate themore » charging settings every time they charge the plug-in electric vehicle in a new location.« less

Mechanistic Understanding of Microbial Plugging for Improved Sweep Efficiency

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

Steven Bryant; Larry Britton

2008-09-30

Microbial plugging has been proposed as an effective low cost method of permeability reduction. Yet there is a dearth of information on the fundamental processes of microbial growth in porous media, and there are no suitable data to model the process of microbial plugging as it relates to sweep efficiency. To optimize the field implementation, better mechanistic and volumetric understanding of biofilm growth within a porous medium is needed. In particular, the engineering design hinges upon a quantitative relationship between amount of nutrient consumption, amount of growth, and degree of permeability reduction. In this project experiments were conducted to obtainmore » new data to elucidate this relationship. Experiments in heterogeneous (layered) beadpacks showed that microbes could grow preferentially in the high permeability layer. Ultimately this caused flow to be equally divided between high and low permeability layers, precisely the behavior needed for MEOR. Remarkably, classical models of microbial nutrient uptake in batch experiments do not explain the nutrient consumption by the same microbes in flow experiments. We propose a simple extension of classical kinetics to account for the self-limiting consumption of nutrient observed in our experiments, and we outline a modeling approach based on architecture and behavior of biofilms. Such a model would account for the changing trend of nutrient consumption by bacteria with the increasing biomass and the onset of biofilm formation. However no existing model can explain the microbial preference for growth in high permeability regions, nor is there any obvious extension of the model for this observation. An attractive conjecture is that quorum sensing is involved in the heterogeneous bead packs.« less

Left Atrial Appendage Closure with Amplatzer Cardiac Plug in Nonvalvular Atrial Fibrillation: Safety and Long-Term Outcome.

PubMed

Costa, Marcio José Montenegro da; Ferreira, Esmeralci; Quintella, Edgard Freitas; Amorim, Bernardo; Fuchs, Alexandre; Zajdenverg, Ricardo; Sabino, Hugo; Albuquerque, Denilson Campos de

2017-12-01

Atrial fibrillation (AF) is a cardiac arrhythmia with high risk for thromboembolic events, specially stroke. To assess the safety of left atrial appendage closure (LAAC) with the Amplatzer Cardiac Plug for the prevention of thromboembolic events in patients with nonvalvular AF. This study included 15 patients with nonvalvular AF referred for LAAC, 6 older than 75 years (mean age, 69.4 ± 9.3 years; 60% of the male sex). The mean CHADS2 score was 3.4 ± 0.1, and mean CHA2DS2VASc , 4.8 ± 1.8, evidencing a high risk for thromboembolic events. All patients had a HAS-BLED score > 3 (mean, 4.5 ± 1.2) with a high risk for major bleeding within 1 year. The device was successfully implanted in all patients, with correct positioning in the first attempt in most of them (n = 11; 73.3%). There was no periprocedural complication, such as device migration, pericardial tamponade, vascular complications and major bleeding. All patients had an uneventful in-hospital course, being discharged in 2 days. The echocardiographic assessments at 6 and 12 months showed neither device migration, nor thrombus formation, nor peridevice leak. On clinical assessment at 12 months, no patient had thromboembolic events or bleeding related to the device or risk factors. In this small series, LAAC with Amplatzer Cardiac Plug proved to be safe, with high procedural success rate and favorable outcome at the 12-month follow-up. (Arq Bras Cardiol. 2017; [online].ahead print, PP.0-0).

Impact of sulfate pollution on anaerobic biogeochemical cycles in a wetland sediment.

PubMed

Baldwin, Darren S; Mitchell, Alison

2012-03-15

The impact of sulfate pollution is increasingly being seen as an issue in the management of inland aquatic ecosystems. In this study we use sediment slurry experiments to explore the addition of sulfate, with or without added carbon, on the anaerobic biogeochemical cycles in a wetland sediment that previously had not been exposed to high levels of sulfate. Specifically we looked at the cycling of S (sulfate, dissolved and particulate sulfide--the latter measured as acid volatile sulfide; AVS), C (carbon dioxide, bicarbonate, methane and the short chain volatile fatty acids formate, acetate, butyrate and propionate), N (dinitrogen, ammonium, nitrate and nitrite) and redox active metals (Fe(II) and Mn(II)). Sulfate had the largest effects on the cycling of S and C. All the added S at lower loadings were converted to AVS over the course of the experiment (30 days). At the highest loading (8 mmol) less than 50% of consumed S was converted to AVS, however this is believed to be a kinetic effect. Although sulfate reduction was occurring in sediments with added sulfate, dissolved sulfide concentrations remained low throughout the study. Sulfate addition affected methanogenesis. In the absence of added carbon, addition of sulfate, even at a loading of 1 mmol, resulted in a halving of methane formation. The initial rate of formation of methane was not affected by sulfate if additional carbon was added to the sediment. However, there was evidence for anaerobic methane oxidation in those sediments with added sulfate and carbon, but not in those sediments treated only with carbon. Surprisingly, sulfate addition had little apparent impact on N dynamics; previous studies have shown that sulfide can inhibit denitrification and stimulate dissimilatory nitrate reduction to ammonia. We propose that because most of the reduced sulfur was in particulate form, levels of dissolved sulfide were too low to interfere with the N cycle. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Catalytic Generation Of Nanometer-sized Diamondoids From Thermal Decomposition Of Organic Matter In Modern Sediments

NASA Astrophysics Data System (ADS)

Wei, Z.; Moldowan, M. J.; Paytan, A.

2005-12-01

Diamondoids are nanoparticles naturally occurring in petroleum and not known to be natural products. Experimental work of artificial maturation on modern sediments was completed to determine if diamondoids can be created from biosynthetic precursors (e.g., n-alkenes, fatty acids, highly branched isoprenoids, sterols, etc.) present in modern sediments. Addition of mineral catalysts (montmorillonite K10, acidic aluminosilicate and calcium carbonate) with distinctive properties to pyrolysis experiments conducted using organic-rich modern sediments can provide information on which type of catalyst is active and effective in the production of diamondoids. Trace amounts of diamondoids were detected in San Francisco Bay, Santa Barbara Basin, and Elkhorn Slough muds. These might have been contributed by slight contamination with unknown oil spills or oil seeps, as supported by the presence of both geological epimers (22S) and biological epimers (22R) for C31-C35 homohopanes in mud extracts. However, diamondoids were not detectable or possibly absent in Celestun Lagoon carbonate which is rich in microfossils. Various quantities of diamondoids were generated from the thermal alteration of organic matter in several modern sediments in the presence and absence of catalysts. It is likely that the formation of diamondoids is coincident with the occurrence of n-alkanes and other biomarkers since the thermal maturation of modern sediments produces a certain amount of diamondoids. Clay minerals usually behave as acidic catalysts in the transformation of organic matter to hydrocarbons. As expected, montmorillonite K10 and acidic aluminosilicate greatly facilitate the formation of diamondoids in modern sediments at 340°C. Rearrangements of certain strained polycyclic carbonium-ion intermediates at Lewis super-acid sites may be responsible for the relatively high abundance of diamondoids upon thermal stress in the presence of montmorillonite K10 or acidic aluminosilicate. In contrast, calcium carbonate shows an inhibition effect on the formation of diamondoids. Therefore, it is likely that these nanoparticle-like diamondoids are formed through a carbonium ion mechanism instead of an electron transfer mechanism.

Formation and burial of pyrite and organic sulfur in mud sediments of the East China Sea inner shelf: Constraints from solid-phase sulfur speciation and stable sulfur isotope

NASA Astrophysics Data System (ADS)

Zhu, Mao-Xu; Shi, Xiao-Ning; Yang, Gui-Peng; Hao, Xiao-Chen

2013-02-01

Solid-phase sulfur speciation and stable sulfur isotopic compositions are used to elucidate the formation and burial of pyrite-sulfur (Spy) and organic sulfur (OS) at three selected sites in mud sediments of the East China Sea (ECS) inner shelf, and to infer potential factors influencing the preservation of Spy and OS in the sediments. Our results in combination with previous studies show that the overall reactivity of sedimentary organic matter (OM) is low, while OM at the site impacted by frequent algal-bloom events displays somewhat enhanced reactivity. We observed characteristically low contents of acid volatile sulfide (AVS) and Spy in the sediments, which can be attributed to low sulfate reduction rate due to high redox potential together with limited availability of labile OM. Several geochemical features, for example, persistent occurrence of S0, good coupling among the profiles of AVS, S0 and Spy, and large 34Spy depletion, all suggest that the polysulfide pathway and disproportionation are likely involved in the pyrite formation. Organic sulfur amounts in the sediments are at the lower end of OS contents reported in many other marine sediments around the world. The sources of OS are both biosynthetic and diagenetic, with the biosynthetic OS being the major share (59-73%). In one site studied (C702), enhanced accumulation of OS within the upper layers (14 cm) is believed to be associated with frequent algal-bloom events. Net burial fluxes of Spy and OS in the three sites studied range from 0.27 to 0.82 mmol/m2/d and from 0.22 to 0.74 mmol/m2/d, respectively. Sedimentation rate and algal-bloom events are two important factors influencing the spatial variability of Spy and OS burial fluxes in the whole shelf.

Mercury methylation and sulfate reduction rates in mangrove sediments, Rio de Janeiro, Brazil: The role of different microorganism consortia.

PubMed

Correia, Raquel Rose Silva; Guimarães, Jean Remy Davée

2017-01-01

Recent studies have shown Hg methylation in mangrove sediments, however, little is known about the different microorganism consortia involved. We investigated the participation of prokaryotes in general, iron-reducing bacteria-IRB, sulfate-reducing bacteria-SRB, methanogens and fungi in Hg methylation and sulfate reduction rates (SRR) in mangrove sediments using iron amendments for IRB and specific inhibitors for the other microorganisms. Sediment samples were collected from two mangrove zones, tidal flat and mangrove forest (named root sediments). Samples were incubated with 203 Hg or 35 SO 4 2- and Me 203 Hg/ 35 Sulfur were measured by liquid scintillation. Methylmercury (MeHg) formation was significantly reduced when SRB (87.7%), prokaryotes (76%) and methanogens (36.5%) were inhibited in root sediments, but only SRB (51.6%) and prokaryotes (57.3%) in tidal flat. However, in the tidal flat, inhibition of methanogens doubled Hg methylation (104.5%). All inhibitors (except fungicide) significantly reduced SRR in both zones. In iron amended tidal flat samples, Hg methylation increased 56.5% at 100 μg g -1 and decreased at 500 and 1000 μg g -1 (57.8 and 82%). In the roots region, however, MeHg formation gradually decreased in response to Fe amendments from 100 μg g -1 (37.7%) to 1000 μg g -1 (93%). SRR decreased in all iron amendments. This first simultaneous evaluation of Hg methylation and sulfate-reduction and of the effect of iron and inhibitors on both processes suggest that SRB are important Hg methylators in mangrove sediments. However, it also suggests that SRB activity could not explain all MeHg formation. This implies the direct or indirect participation of other microorganisms such as IRB and methanogens and a complex relationship among these groups. Copyright © 2016. Published by Elsevier Ltd.

Decoupling flood and interflood deposits for delta island formation and channel bifurcation

NASA Astrophysics Data System (ADS)

Daniller-Varghese, M. S.; Kim, W.

2016-12-01

Channel islands' size and organization dictate delta networks' morphology. To understand their complex network organization, a single channel island node within that network should be investigated first as the fundamental building block. When a sediment-laden flow enters slack water, it loses momentum and carrying capacity, depositing its sediment. As sediment accumulates, flow moves around it and a mouth bar island develops. We present an experimental investigation of island formation and channel bifurcation using the Sediment Transport and Earth-surface Processes (STEP) basin. We made mouth bar deposits and flow bifurcations in transport-limited turbulent conditions. Time-lapse images, elevation scans on the deltaic surface, and a low-cost particle imaging velocimetry system allow us to characterize the flow and depositional evolution of our experimental islands. Using two flow discharges (0.355 l/s, 6 l/s) and uniform sediment, our experiments have two characteristic advection lengths and corresponding deposit types. One, associated with interflood bedload transport, and the other with flood-suspended transport: proximal low-angle deposits and distal steep deposits, respectively. By varying the frequency of floods (one every 20s-20 mins) while keeping sediment and water mass constant across experiments, we are able to control the time and spatial organization of these two deposit types and examine the effect on bifurcation length and bifurcation incidence time. As the interflood flow deposit and flood deposit accumulate sediment over time, the interflood deposit encroaches onto the flood deposit. Flow is routed from the interflood deposit to the flood deposit but does not have the momentum to uniformly cover it. The flow becomes unsteady, and bifurcates around an island. After the bifurcation, the island's vertical aggradation rate also increases. The experiments suggest that the interaction between deposits stemming from different particle advection lengths is a sufficient condition for island formation and flow bifurcation.

Orbital forcing of climate 1.4 billion years ago.

PubMed

Zhang, Shuichang; Wang, Xiaomei; Hammarlund, Emma U; Wang, Huajian; Costa, M Mafalda; Bjerrum, Christian J; Connelly, James N; Zhang, Baomin; Bian, Lizeng; Canfield, Donald E

2015-03-24

Fluctuating climate is a hallmark of Earth. As one transcends deep into Earth time, however, both the evidence for and the causes of climate change become difficult to establish. We report geochemical and sedimentological evidence for repeated, short-term climate fluctuations from the exceptionally well-preserved ∼1.4-billion-year-old Xiamaling Formation of the North China Craton. We observe two patterns of climate fluctuations: On long time scales, over what amounts to tens of millions of years, sediments of the Xiamaling Formation record changes in geochemistry consistent with long-term changes in the location of the Xiamaling relative to the position of the Intertropical Convergence Zone. On shorter time scales, and within a precisely calibrated stratigraphic framework, cyclicity in sediment geochemical dynamics is consistent with orbital control. In particular, sediment geochemical fluctuations reflect what appear to be orbitally forced changes in wind patterns and ocean circulation as they influenced rates of organic carbon flux, trace metal accumulation, and the source of detrital particles to the sediment.

Origin and diagenetic transformations of C 25 and C 30 highly branched isoprenoid sulphur compounds: Further evidence for the formation of organically bound sulphur during early diagenesis

NASA Astrophysics Data System (ADS)

Kohnen, M. E. L.; Damsté, J. S. Slnninghe; Kock-van Dalen, A. C.; Haven, H. L. Ten; Rullkötter, J.; De Leeuw, J. W.

1990-11-01

A number of C 25 and C 30 highly branched isoprenoid (HBI) sulphur compounds (E.G., thiolanes, 1-oxo-thiolanes, thiophenes, and benzo[ b]thiophenes) with 2,6,10,14-tetramethyl-7-(3-methylpentyl)pentadecane and 2,6,10,14,18-pentamethyl-7-(3-methylpentyl)nonadecane carbon skeletons were identified in sediments, ranging from Holocene to Upper Cretaceous. These identifications are based on mass spectral characterisation, desulphurisation, and, in some cases, by comparison of mass spectral and relative retention time data with those of authentic standards. The presence of unsaturated C 25 and C 30 HBI thiolanes in a Recent sediment from the Black Sea (age 3-6 × 10 3 a) strongly supports their formation during early diagenesis. The co-occurrence of HBI polyenes (C 25 and C 30) and unsaturated HBI thiolanes (C 25 and C 30) possessing two double bonds less than the corresponding HBI polyenes, in this Recent sediment, testifies to the formation of unsaturated HBI thiolanes by a reaction of inorganic sulphur species with double bonds of the HBI polyenes. Furthermore, a diagenetic scheme for HBI sulphur compounds is proposed based on the identification of HBI sulphur compounds in sediment samples with different maturity levels.

The formation and evolution of the barrier islands of Inhaca and Bazaruto, Mozambique

NASA Astrophysics Data System (ADS)

Armitage, S. J.; Botha, G. A.; Duller, G. A. T.; Wintle, A. G.; Rebêlo, L. P.; Momade, F. J.

2006-12-01

The barrier islands of Inhaca and Bazaruto are related to the extensive coastal dune system of the Mozambican coastal plain, south-east Africa. Optically stimulated luminescence (OSL) dating of key stratigraphic units indicates that accretion of sediment within these systems is episodic. Both islands appear to have been initiated as spits extending from structural offsets in the coastline. Superposition of significant quantities of sediment upon these spits during subsequent sea-level highstands formed the core of the islands, which were anchored and protected by beachrock and aeolianite formation. At least two distinct dune-building phases occurred during Marine Oxygen Isotope Stage (MIS) 5, tentatively attributed to marine transgressions during sub-stages 5e and 5c. Although some localized reactivation of dune surfaces occurred prior to the Holocene, large quantities of sediment were not deposited on either island during the low sea-levels associated with MIS 2. Significant dune-building and sediment reworking occurred immediately prior to and during the Holocene, though it is not clear whether these processes were continuous or episodic. Significant erosion of the eastern shoreline of Bazaruto suggests that it is far less stable than Inhaca and may suffer further large-scale erosion. A model is presented for the formation of barrier islands along the Mozambican coastal plain.

Antibiotic resistance and biofilm formation of some bacteria isolated from sediment, water and fish farms in Malaysia

NASA Astrophysics Data System (ADS)

Faja, Orooba Meteab; Usup, Gires; Ahmad, Asmat

2018-04-01

A total of 90 isolates of bacteria were isolated, from sediment (10) samples, water (10) samples and fish (12) samples (Sea bass, Snapper, Grouper and Tilapia). These include 22 isolates of bacteria from sediment, 28 isolates from water and 40 isolates from fish. All the isolates were tested for sensitivity to 13 antibiotics using disc diffusion method. The isolates showed high resistance to some antibiotics based on samples source. Isolates from sediment showed highest resistance toward novobiocin, kanamycin, ampicillin and streptomycin while isolates from water showed highest resistance against vancomycin, penicillin, streptomycin and tetracycline, in contrast, in fish sample showed highest resistance toward vancomycin, ampicillin, streptomycin and tetracycline. Most of the isolates showed biofilm formation ability with different degrees. Out of 22 bacteria isolates from water, two isolates were weak biofilm formers, six isolates moderate biofilm formers and fourteen isolates strong biofilm formers. While, out of 28 bacteria isolates from water one isolate was weak biofilm former, five isolates moderate biofilm formers and 22 strong biofilm formers Fish isolate showed three isolates (8%) moderate biofilm formers and 27 isolates strong biofilm formers. Biofilm formation was one of the factors that lead to antibiotic resistance of the bacterial isolates from these samples.

Beaver assisted river valley formation

USGS Publications Warehouse

Westbrook, Cherie J.; Cooper, D.J.; Baker, B.W.

2011-01-01

We examined how beaver dams affect key ecosystem processes, including pattern and process of sediment deposition, the composition and spatial pattern of vegetation, and nutrient loading and processing. We provide new evidence for the formation of heterogeneous beaver meadows on riverine system floodplains and terraces where dynamic flows are capable of breaching in-channel beaver dams. Our data show a 1.7-m high beaver dam triggered overbank flooding that drowned vegetation in areas deeply flooded, deposited nutrient-rich sediment in a spatially heterogeneous pattern on the floodplain and terrace, and scoured soils in other areas. The site quickly de-watered following the dam breach by high stream flows, protecting the deposited sediment from future re-mobilization by overbank floods. Bare sediment either exposed by scouring or deposited by the beaver flood was quickly colonized by a spatially heterogeneous plant community, forming a beaver meadow. Many willow and some aspen seedlings established in the more heavily disturbed areas, suggesting the site may succeed to a willow carr plant community suitable for future beaver re-occupation. We expand existing theory beyond the beaver pond to include terraces within valleys. This more fully explains how beavers can help drive the formation of alluvial valleys and their complex vegetation patterns as was first postulated by Ruedemann and Schoonmaker in 1938. ?? 2010 John Wiley & Sons, Ltd.

National Plug-In Electric Vehicle Infrastructure Analysis

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

Wood, Eric; Rames, Clement; Muratori, Matteo

This report addresses the fundamental question of how much plug-in electric vehicle (PEV) charging infrastructure—also known as electric vehicle supply equipment (EVSE)—is needed in the United States to support both plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs).

Rare earth, major, and trace element composition of Monterey and DSDP chert and associated host sediment: Assessing the influence of chemical fractionation during diagenesis

USGS Publications Warehouse

Murray, R.W.; Buchholtz ten Brink, Marilyn R.; Gerlach, David C.; Russ III, G. Price; Jones, David L.

1992-01-01

Chert and associated host sediments from Monterey Formation and Deep Sea Drilling Project (DSDP) sequences were analyzed in order to assess chemical behavior during diagenesis of biogenic sediments. The primary compositional contrast between chert and host sediment is a greater absolute SiO2 concentration in chert, often with final SiO2 ≥ 98 wt%. This contrast in SiO2 (and SiAl">SiAl) potentially reflects precursor sediment heterogeneity, diagenetic chemical fractionation, or both. SiO2 concentrations and SiAl">SiAl ratios in chert are far greater than in modern siliceous oozes, however and often exceed values in acid-cleaned diatom tests. Compositional contrasts between chert and host sediment are also orders-of-magnitude greater than between multiple samples of the host sediment. Calculations based on the initial composition of adjacent host, observed porosity reductions from host to chert and a postulated influx of pure SiO2, construct a chert composition which is essentially identical to observed SiO2 values in chert. Thus, precursor heterogeneity does not seem to be the dominant factor influencing the current chert composition for the key elements of interest. In order to assess the extent of chemical fractionation during diagenesis, we approximate the precursor composition by analyzing host sediments adjacent to the chert.The SiO2 concentration contrast seems caused by biogenic SiO2 dissolution and transport from the local adjacent host sediment and subsequent SiO2reprecipitation in the chert. Along with SiO2, other elements are often added (with respect to Al) to Monterey and DSDP chert during silicification, although absolute concentrations decrease. The two Monterey quartz chert nodules investigated, in contrast to the opal-CT and quartz chert lenses, formed primarily by extreme removal of carbonate and phosphate, thereby increasing relative SiO2 concentrations. DSDP chert formed by both carbonate/phosphate dissolution and SiO2 addition from the host. Manganese is fractionated during chert formation, resulting in MnOAl2O3">MnOAl2O3 ratios that no longer record the depositional signal of the precursor sediment.REE data indicate only subtle diagenetic fractionation across the rare earth series. CeCe∗">CeCe* values do not change significantly during diagenesis of either Monterey or DSDP chert. EuEu∗">EuEu* decreases slightly during formation of DSDP chert. LanYbn">LanYbn is affected only minimally as well. During formation of one Monterey opal-CT chert lens, REEAl">REEAl ratios show subtle distribution changes at Gd and to a lesser extent near Nd and Ho. REE compositional contrasts between diagenetic states of siliceous sediment and chert are of a vastly smaller scale than has been noted between different depositional environments of marine sediment, indicating that the paleoenvironmental REE signature is not obscured by diagenetic overprinting.

Nozzle dam having a unitary plug

DOEpatents

Veronesi, L.; Wepfer, R.M.

1992-12-15

Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator is disclosed. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket. 16 figs.

Nozzle dam having a unitary plug

DOEpatents

Veronesi, Luciano; Wepfer, Robert M.

1992-01-01

Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket.

Stimulus learning and response learning by observation in the European starling, in a two-object/two-action test.

PubMed

Campbell; Heyes; Goldsmith

1999-07-01

Juvenile European starlings, Sturnus vulgaris, were allowed to observe a conspecific demonstrator using its beak to remove one of two distinctively coloured objects (i.e. a red or a black plug) from a hole in the lid of a plastic box. Both plugs could be removed by either pulling up on a loop of string inserted through the centre of the plug, or pushing down on the plug. When subsequently allowed access to the plugs, and rewarded with food for all removal responses, regardless of the object to which they were made and their direction, observer birds removed the same plug in the same direction as their demonstrator. These results suggest that the two-object/two-action paradigm is a valuable procedure for testing for the simultaneous effects of learning about a stimulus and a response, an object and an action, through conspecific observation. Copyright 1999 The Association for the Study of Animal Behaviour.

Magma-sediment interactions in the Limagne trench (Massif Central, France): distinction between phreatomagmatic and stricto-sensu peperitic processes

NASA Astrophysics Data System (ADS)

Leibrandt, Sebastien; Bénard, Antoine; Brigaud, Benjamin

2013-04-01

Magma-sediment interactions provide important information to reconstruct paleo-eruption dynamics in hydromagmatic environments. The lithofacies resulting from these interactions are usually named "peperite" as first described on rocks from the Limagne area (Massif Central, France). Nevertheless, it is nowadays admitted that both fluidal and blocky peperite formation refers to mostly non-explosive, hydrodynamic disintegration of magma intruding and mingling with unconsolidated wet sediments (e.g. Skilling et al., 2002). Here we observe magma-limestones interactions (i.e. explosive and non-explosive) in phreatomagmatic vent-filling deposits, from outcrop scale to thin-section observations, with polarized, electronic and cathodoluminescence microscopy. Our field study is based on the comparison of selected localities from the Limagne trench that are mapped as peperites but which apparently only record phreatomagmatic processes leading to the deposit of sediment-rich maar diatreme material. Microscopic characterization mainly focuses on juvenile clasts and host carbonate sediment textural relationships, when mixed together and dispersed in the maar diatreme material. We deduce the mechanisms and timing of interaction of several generations of magmatic clasts with host pristine carbonate sediments or pre-existing volcaniclastic breccia. The extent of mixing and dispersion of the magmatic clasts is assessed in relation with the emplacement dynamics, magmatic cooling rates and host sediment properties. In this regard, cathodoluminescence microscopy allows us to deduce the properties of sediment before, during and after interaction, which also helps to reconstruct the paleo-environmental frame. As a first outcome of this study, we distinguish (1) early syn-eruptive fragmented material during phreatomagmatic magma-sediment interaction from (2) secondary, non-explosive, magmatic intrusions in poorly consolidated and water-saturated vent-filling deposits. This second process can solely give birth to the stricto-sensu fluidal to blocky peperite microtexture, which we clearly distinguish for the first time in the Limagne area. A second outcome emerges thanks to the several approaches we use for microscopic characterization, which possibly reveal high-grade, non-explosive mingling of liquefied sediment with magma at the sub-millimetre scale. These observations provide new insights into peperite formation processes in carbonate sediments, when both considering experiments (e.g. Zimanowski and Büttner, 2002) and worldwide field observations in contrasting environments (e.g. McClintock & White, 2002). McClintock, M.K., White, J.D.L., 2002. Granulation of weak rock as a precursor to peperite formation: coal peperite, Coombs Hill, Antartica. Journal of Volcanology and Geothermal Research, 114, 205-217. Skilling, I.P., White, J.D.L., McPhie, J., 2002. Peperite: a review of magma-sediment mingling. Journal of Volcanology and Geothermal Research, 114, 1-17. Zimanowski, B., Büttner, R., 2002. Dynamic mingling of magma and liquefied sediments. Journal of Volcanology and Geothermal Research, 114, 37-44.

Effect of cement dosage and early curing towards Kuala Perlis dredged marine sediments: a ɛv - σv and SEM-EDX approach

NASA Astrophysics Data System (ADS)

Syakeera Nordin, Nurul; Chan, Chee-Ming

2017-11-01

Cement is the primary material used in solidifying the soft soils. This material was applied in solidifying Kuala Perlis dredged marine sediments (DMS). These unwanted sediments are classified as high plasticity silt, MH with 3.36 LL of wc/LL value. At dosage 10 and 20 % of cemented-DMS and 3 days curing time, compression curve results shows the settlement criteria were enhanced than the natural DMS. Unfortunately, the settlement criteria are not complies with the permissible settlement limit and applicable pressure. The formation of cementing compounds appears in the SEM micrograph for 10 and 20 % of cemented-DMS. EDX analysis shows the Ca:Si ratio were increased for cemented-DMS due to the formation of C-S-H gel.

Development of hydrate risk quantification in oil and gas production

NASA Astrophysics Data System (ADS)

Chaudhari, Piyush N.

Subsea flowlines that transport hydrocarbons from wellhead to the processing facility face issues from solid deposits such as hydrates, waxes, asphaltenes, etc. The solid deposits not only affect the production but also pose a safety concern; thus, flow assurance is significantly important in designing and operating subsea oil and gas production. In most subsea oil and gas operations, gas hydrates form at high pressure and low temperature conditions, causing the risk of plugging flowlines, with a undesirable impact on production. Over the years, the oil and gas industry has shifted their perspective from hydrate avoidance to hydrate management given several parameters such as production facility, production chemistry, economic and environmental concerns. Thus, understanding the level of hydrate risk associated with subsea flowlines is an important in developing efficient hydrate management techniques. In the past, hydrate formation models were developed for various flow-systems (e.g., oil dominated, water dominated, and gas dominated) present in the oil and gas production. The objective of this research is to extend the application of the present hydrate prediction models for assessing the hydrate risk associated with subsea flowlines that are prone to hydrate formation. It involves a novel approach for developing quantitative hydrate risk models based on the conceptual models built from the qualitative knowledge obtained from experimental studies. A comprehensive hydrate risk model, that ranks the hydrate risk associated with the subsea production system as a function of time, hydrates, and several other parameters, which account for inertial, viscous, interfacial forces acting on the flow-system, is developed for oil dominated and condensate systems. The hydrate plugging risk for water dominated systems is successfully modeled using The Colorado School of Mines Hydrate Flow Assurance Tool (CSMHyFAST). It is found that CSMHyFAST can be used as a screening tool in order to reduce the parametric study that may require a long duration of time using The Colorado School of Mines Hydrate Kinetic Model (CSMHyK). The evolution of the hydrate plugging risk along flowline-riser systems is modeled for steady state and transient operations considering the effect of several critical parameters such as oil-hydrate slip, duration of shut-in, and water droplet size on a subsea tieback system. This research presents a novel platform for quantification of the hydrate plugging risk, which in-turn will play an important role in improving and optimizing current hydrate management strategies. The predictive strength of the hydrate risk quantification and hydrate prediction models will have a significant impact on flow assurance engineering and design with respect to building safe and efficient hydrate management techniques for future deep-water developments.

Nonlinear saturation of the Rayleigh instability due to oscillatory flow in a liquid-lined tube

NASA Astrophysics Data System (ADS)

Halpern, David; Grotberg, James B.

2003-10-01

In this paper, the stability of core annular flows consisting of two immiscible fluids in a cylindrical tube with circular cross-section is examined. Such flows are important in a wide range of industrial and biomedical applications. For example, in secondary oil recovery, water is pumped into the well to displace the remaining oil. It is also of relevance in the lung, where a thin liquid film coats the inner surface of the small airways of the lungs. In both cases, the flow is influenced by a surface-tension instability, which may induce the breakup of the core fluid into short plugs, reducing the efficiency of the oil recovery, or blocking the passage of air in the lung thus inducing airway closure. We consider the stability of a thin film coating the inner surface of a rigid cylindrical tube with the less viscous fluid in the core. For thick enough films, the Rayleigh instability forms a liquid bulge that can grow to eventually create a plug blocking the tube. The analysis explores the effect of an oscillatory core flow on the interfacial dynamics and particularly the nonlinear stabilization of the bulge. The oscillatory core flow exerts tangential and normal stresses on the interface between the two fluids that are simplified by uncoupling the core and film analyses in the thin-film high-frequency limit of the governing equations. Lubrication theory is used to derive a nonlinear evolution equation for the position of the air liquid interface which includes the effects of the core flow. It is shown that the core flow can prevent plug formation of the more viscous film layer by nonlinear saturation of the capillary instability. The stabilization mechanism is similar to that of a reversing butter knife, where the core shear wipes the growing liquid bulge back on to the tube wall during the main tidal volume stroke, but allows it to grow back as the stoke and shear turn around. To be successful, the leading film thickness ahead of the bulge must be smaller than the trailing film thickness behind it, a requirement necessitating a large enough core capillary number which promotes a large core shear stress on the interface. The core capillary number is defined to be the ratio of core viscous forces to surface tension forces. When this process is tuned correctly, the two phases balance and there is no net growth of the liquid bulge over one cycle. We find that there is a critical frequency above which plug formation does not occur, and that this critical frequency increases as the tidal volume amplitude of the core flow decreases.

Colloid formation in Hanford sediments reacted with simulated tank waste.

PubMed

Mashal, Kholoud; Harsh, James B; Flury, Markus; Felmy, Andrew R; Zhao, Hongting

2004-11-01

Solutions of high pH, ionic strength, and aluminum concentration have leaked into the subsurface from underground waste storage tanks atthe Hanford Reservation in Washington State. Here, we test the hypothesis that these waste solutions alter and dissolve the native minerals present in the sediments and that colloidal (diameter < 2 microm) feldspathoids form. We reacted Hanford sediments with simulated solutions representative of Hanford waste tanks. The solutions consisted of 1.4 or 2.8 mol/kg NaOH, 0.125 or 0.25 mol/kg NaAlO4, and 3.7 mol/kg NaNO3 and were contacted with the sediments for a period of 25 or 40 days at 50 degrees C. The colloidal size fraction was separated from the sediments and characterized in terms of mineralogy, morphology, chemical composition, and electrophoretic mobility. Upon reaction with tank waste solutions, native minerals released Si and other elements into the solution phase. This Si precipitated with the Al present in the waste solutions to form secondary minerals, identified as the feldspathoids cancrinite and sodalite. The solution phase was modeled with the chemical equilibrium model GMIN for solution speciation and saturation indices with respect to sodalite and cancrinite. The amount of colloidal material in the sediments increased upon reaction with waste solutions. At the natural pH found in Hanford sediments (pH 8) the newly formed minerals are negatively charged, similar to the unreacted colloidal material present in the sediments. The formation of colloidal material in Hanford sediments upon reaction with tank waste solutions is an important aspect to consider in the characterization of Hanford tank leaks and may affect the fate of hazardous radionuclides present in the tank waste.

30 CFR 18.41 - Plug and receptacle-type connectors.

Code of Federal Regulations, 2014 CFR

2014-07-01

... electrically interlocked with an automatic circuit-interrupting device. (i) Mechanically interlocked connectors... shall be removed before the plug can be withdrawn and the electrical energy in the interlocking pilot.... (d) Molded-elastomer connectors will be acceptable provided: (1) Any free space within the plug or...

30 CFR 18.41 - Plug and receptacle-type connectors.

Code of Federal Regulations, 2010 CFR

2010-07-01

... electrically interlocked with an automatic circuit-interrupting device. (i) Mechanically interlocked connectors... shall be removed before the plug can be withdrawn and the electrical energy in the interlocking pilot.... (d) Molded-elastomer connectors will be acceptable provided: (1) Any free space within the plug or...

30 CFR 18.41 - Plug and receptacle-type connectors.

Code of Federal Regulations, 2013 CFR

2013-07-01

... electrically interlocked with an automatic circuit-interrupting device. (i) Mechanically interlocked connectors... shall be removed before the plug can be withdrawn and the electrical energy in the interlocking pilot.... (d) Molded-elastomer connectors will be acceptable provided: (1) Any free space within the plug or...

30 CFR 18.41 - Plug and receptacle-type connectors.

Code of Federal Regulations, 2012 CFR

2012-07-01

... electrically interlocked with an automatic circuit-interrupting device. (i) Mechanically interlocked connectors... shall be removed before the plug can be withdrawn and the electrical energy in the interlocking pilot.... (d) Molded-elastomer connectors will be acceptable provided: (1) Any free space within the plug or...

30 CFR 18.41 - Plug and receptacle-type connectors.

Code of Federal Regulations, 2011 CFR

2011-07-01

... electrically interlocked with an automatic circuit-interrupting device. (i) Mechanically interlocked connectors... shall be removed before the plug can be withdrawn and the electrical energy in the interlocking pilot.... (d) Molded-elastomer connectors will be acceptable provided: (1) Any free space within the plug or...

Intraocular foreign-body hazard during vitrectomy.

PubMed

Bovino, J A; Marcus, D F

1982-03-01

We noted two instances of forceps-induced fragmentation of the bar used for scleral plug storage during vitreous surgery. The silicone bar material was adherent to the plug in both cases. Because this represents a significant intraocular foreign body hazard, the scleral plug should be carefully inspected before insertion.

Rotating plug bearing and seal

DOEpatents

Wade, Elman E.

1977-01-01

A bearing and seal structure for nuclear reactors utilizing rotating plugs above the nuclear reactor vessel. The structure permits lubrication of bearings and seals of the rotating plugs without risk of the lubricant draining into the reactor vessel below. The structure permits lubrication by utilizing a rotating outer race bearing.

Dynamics of seismogenic volcanic extrusion resisted by a solid surface plug, Mount St. Helens, 2004-2005: Chapter 21 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

USGS Publications Warehouse

Iverson, Richard M.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

2008-01-01

The 2004-5 eruption of Mount St. Helens exhibited sustained, near-equilibrium behavior characterized by nearly steady extrusion of a solid dacite plug and nearly periodic occurrence of shallow earthquakes. Diverse data support the hypothesis that these earthquakes resulted from stick-slip motion along the margins of the plug as it was forced incrementally upward by ascending, solidifying, gas-poor magma. I formalize this hypothesis with a mathematical model derived by assuming that magma enters the base of the eruption conduit at a steady rate, invoking conservation of mass and momentum of the magma and plug, and postulating simple constitutive equations that describe magma and conduit compressibilities and friction along the plug margins. Reduction of the model equations reveals a strong mathematical analogy between the dynamics of the magma-plug system and those of a variably damped oscillator. Oscillations in extrusion velocity result from the interaction of plug inertia, a variable upward force due to magma pressure, and a downward force due to the plug weight. Damping of oscillations depends mostly on plug-boundary friction, and oscillations grow unstably if friction exhibits rate weakening similar to that observed in experiments. When growth of oscillations causes the extrusion rate to reach zero, however, gravity causes friction to reverse direction, and this reversal instigates a transition from unstable oscillations to self-regulating stick-slip cycles. The transition occurs irrespective of the details of rate-weakening behavior, and repetitive stick-slip cycles are, therefore, robust features of the system’s dynamics. The presence of a highly compressible elastic driving element (that is, magma containing bubbles) appears crucial for enabling seismogenic slip events to occur repeatedly at the shallow earthquake focal depths (8 N. These results imply that the system’s self-regulating behavior is not susceptible to dramatic change--provided that the rate of magma ascent remains similar to the rate of magma accretion at the base of the plug, that plug surface erosion more or less compensates for mass gain due to basal accretion, and that magma and rock properties do not change significantly. Even if disequilibrium initial conditions are imposed, the dynamics of the magma-plug system are strongly attracted to self-regulating stick-slip cycles, although this self-regulating behavior can be bypassed on the way to runaway behavior if the initial state is too far from equilibrium.

Sediment entrainment into sea ice and transport in the Transpolar Drift: A case study from the Laptev Sea in winter 2011/2012

NASA Astrophysics Data System (ADS)

Wegner, C.; Wittbrodt, K.; Hölemann, J. A.; Janout, M. A.; Krumpen, T.; Selyuzhenok, V.; Novikhin, A.; Polyakova, Ye.; Krykova, I.; Kassens, H.; Timokhov, L.

2017-06-01

Sea ice is an important vehicle for sediment transport in the Arctic Ocean. On the Laptev Sea shelf (Siberian Arctic) large volumes of sediment-laden sea ice are formed during freeze-up in autumn, then exported and transported across the Arctic Ocean into Fram Strait where it partly melts. The incorporated sediments are released, settle on the sea floor, and serve as a proxy for ice-transport in the Arctic Ocean on geological time scales. However, the formation process of sediment-laden ice in the source area has been scarcely observed. Sediment-laden ice was sampled during a helicopter-based expedition to the Laptev Sea in March/April 2012. Sedimentological, biogeochemical and biological studies on the ice core as well as in the water column give insights into the formation process and, in combination with oceanographic process studies, on matter fluxes beneath the sea ice. Based on satellite images and ice drift back-trajectories the sediments were likely incorporated into the sea ice during a mid-winter coastal polynya near one of the main outlets of the Lena River, which is supported by the presence of abundant freshwater diatoms typical for the Lena River phytoplankton, and subsequently transported about 80 km northwards onto the shelf. Assuming ice growth of 12-19 cm during this period and mean suspended matter content in the newly formed ice of 91.9 mg l-1 suggests that a minimum sediment load of 8.4×104 t might have been incorporated into sea ice. Extrapolating these sediment loads for the entire Lena Delta region suggests that at least 65% of the estimated sediment loads which are incorporated during freeze-up, and up to 10% of the annually exported sediment load may be incorporated during an event such as described in this paper.

Discriminating Sediment Supply versus Accommodation Controls on Late Cretaceous Foreland Basin Stratigraphic Architecture in the Book Cliffs, Utah using Detrital Zircon Double Dating

NASA Astrophysics Data System (ADS)

Bartschi, N.; Saylor, J. E.

2016-12-01

Middle to late Campanian strata of the Book Cliffs, Utah record the Late Cretaceous deposition of three clastic wedges in the North American Cordilleran foreland basin east of the Sevier thrust-belt. Variations in wedge geometries provide an opportunity to evaluate the effects of sediment supply versus accommodation on foreland basin stratal architecture. There is a significant increase in eastward progradation rate from the Lower to the Upper Castlegate Sandstone. However, the progradation rate decreases in the overlying Bluecastle and Price River formations, as well as the laterally equivalent Farrer and Tuscher formations. Rapid progradation during Upper Castlegate deposition may be caused by increased sediment supply from either rapid exhumation of the Sevier thrust-belt or introduction of a new sediment source. Alternatively, reduced accommodation within the proximal foreland basin from uplifts associated with Laramide deformation, or a transition from flexural to dynamic subsidence, could produce the observed rapid wedge progradation. Changes in sediment provenance and source-area exhumation rate can be identified using a combination of detrital zircon U-Pb geochronology and (U-Th)/He thermochronology. Quantitative comparisons between collected samples and published provenance data indicates an upsection increase in a new sediment source, revealing a significant overall shift in provenance between wedge boundaries. This change in provenance is coupled by an upsection decrease in lag time between the Lower and Upper Castlegate, consistent with an increase in exhumation rate. Conversely, there is no change in lag time between the Upper Castlegate and overlying Price River Formation, suggesting a relatively constant exhumation rate. Near-zero lag times during the Upper Castlegate is consistent with rapid exhumation associated with increased thrusting of the Sevier thrust-belt. Therefore, progradation of the Upper Castlegate can be attributed to an increase in sediment supply due to both rapid exhumation of the Sevier thrust-belt and introduction of a new sediment source. However, the data do not rule out the potential influence of reduced accommodation associated with early Laramide deformation during Upper Castlegate deposition.

Relating modes of extension to the spatial and temporal distribution of major sediment unconformities at passive margins

NASA Astrophysics Data System (ADS)

Andrés-Martínez, Miguel; Pérez-Gussinyé, Marta; Armitage, John; Morgan, Jason P.

2017-04-01

Rifting is a regional process which results in thinning of the crust over hundreds of kilometres. However, basins where deposition takes place could have different subsidence histories due to local graben-bounding fault kinetics. A change in the rift dynamics often results in a displacement of the basin depocenters, with subsequent erosion of old sediments and later deposition, creating an unconformity. Unconformities of regional character are typically studied to unveil the overall rift deformation history, and major ones separating syn- and post-kinematic sediments are often associated with break-up of the continental crust. However, evolution of the basement deformation is typically challenging to study since reflection images are usually diffuse at these depths and boreholes are typically scarce, which complicates the dating of the sediments overlying the basement. Consequently, relating the deformation styles and rift evolution to unconformities is not straight forward. We use numerical models in order to approach the meaning of regional unconformities and to study the sedimentation patterns under different modes of extension. Our models solve 2D Stokes flow for rocks treated as non-Newtonian bodies, together with heat conservation equation. Viscosities and densities depend on temperatures. Elasticity and plasticity are plugged-in in the mechanical formulation. We also use strain softening to simulate faulting and shear zones. The top boundary is a free-surface so that tectonics result in topography. Additionally, we update this topography every time step using a sediment transport model, and we store information about depositional times, paleo-depths and erosional events. These models allow for the recovery of the basement deformation during rift evolution simultaneously to the recovery of sedimentation history. Here, we run models with different crustal rheologies to reproduce different extensional modes. This allows us to contrast sedimentation patterns and unconformities under variable kinetic scenarios, from regional to faulted-block scales. We find that unconformities are generally associated to a change in the locus of extension. In models with intermediate-strength crust, sequential faulting takes place, so that only one fault is active at a time and occur in the hanging wall of the previous fault, resulting in asymmetric conjugate margins. In this case a major unconformity separates syn- and post-kinematic sediments. Both syn- and post-kinematic sediments young oceanwards and the unconformity dates the time in which extension abandons the area in favour of new faults forming oceanwards. Models with weaker crusts display extension along a wide region, with overprinting of different faulting phases. Eventually, deformation localizes in a narrow region due to cooling, and crustal break-up occurs. In this case, a first set of unconformities separates different phases of faulting inside the syn-kinematic sediments, and later unconformities separate syn-kinematic and post-kinematic sediments, dating the time at which extension localizes. We also find that unconformities date the crustal break-up only when they develop in the vicinity of the break-up locus. This stresses on that terms such as syn- and post-rift sediments and break-up unconformity should be handled carefully when seismic interpretation is done, and also provides support for unconformities as rifting story-tellers.

Lithostratigraphie, sédimentologie et évolution de deux bassins molassiques intramontagneux de la chaine Pan-Africaine: la Série pourprée de l'Ahnet, Nord-Ouest du Hoggar, Algérie

NASA Astrophysics Data System (ADS)

Ait-Kaci Ahmed, Ali; Moussine-Pouchkine, Alexis

The study of two of the intermontane molassic basins of the 'Série pourprée de l'Ahnet' shows that they developed independently both in time and space. The characteristics of their thick sedimentary infillings are quite different. The Ouallen basin is filled by essentially fine-grained sediments which were deposited in continental then marine or lacustrine environments; these sediments thicen from east to west. The In Semmen basin is characterised by coarser sediments which were deposited from south to north, in alluvial fan, fluvial, deltaic and slope environments. This basin is also characterised by an episode of carbonate sedimentation leading to the formation of a remarkable thin layer of carbonate, covering the entire sedimentary area, and perhaps related to a volcanic rhyolitic event. The history of the two basins is also marked by obvious tectonic events simultaneous with the sedimentation and related to the recurrent faulting of major Pan-African faults. These led to the formation of very coarse fanglomerates located near the fault scarps, and are probably responsible for the shape and the evolution of the basins.

Application of zeolitic material synthesized from thermally treated sediment to the removal of trivalent chromium from wastewater.

PubMed

Guan, Qingyu; Wu, Deyi; Lin, Yan; Chen, Xuechu; Wang, Xinze; Li, Chunjie; He, Shengbing; Kong, Hainan

2009-08-15

Zeolitic materials were synthesized from thermally treated sediment by alkali treatment using different NaOH/sediment ratios. Characterization of the materials was done by XRD, FTIR, cation exchange capacity and specific surface area. Use of high NaOH/sediment ratio favored the formation of zeolite. The potential value of the zeolitic materials for the retention of trivalent chromium from water was examined. The maximum of Cr(III) sorption by the zeolitic materials, determined by a repeated batch equilibration method, ranged from 38.9 to 75.8 mg/g which was much greater than that of the thermally treated sediment (6.3 mg/g). No release of sorbed Cr(III) by 1.0M MgCl(2) at pH 7 was observed but Cr(III) desorption by ionic electrolyte increased with decreasing pH. The zeolitic materials could completely remove Cr(III) from wastewater even in the presence of Na(+) and Ca(2+) with high concentrations with a dose above 2.5 g/L. The pH-dependent desorption behavior and the high selectivity of zeolitic material for Cr(III) were explained by sorption at surface hydroxyl sites and formation of surface precipitates.

Soft-sediment deformation in a tectonically active area: The Plio-Pleistocene Zarzal Formation in the Cauca Valley (Western Colombia)

NASA Astrophysics Data System (ADS)

Neuwerth, Ralph; Suter, Fiore; Guzman, Carlos A.; Gorin, Georges E.

2006-04-01

The Plio-Pleistocene Zarzal Formation corresponds to fluvio-lacustrine sediments deposited in an intramontane depression within the Colombian Andes, associated with the Cauca-Romeral Fault System. It crops out mainly in the Cauca Valley where numerous field sections have permitted the mapping of the vertical and lateral lithological variations. Lacustrine deposits of sands, silts, clays and diatomites are interbedded with fluvial sand and gravel beds and fluvio-volcanic mass flows derived from the volcanic Central Cordillera. Numerous soft-sediment deformation structures are encountered in this formation, particularly in fine- to medium-grained sands, silts and clays: load structures (load casts, flame structures, pseudonodules), water escape structures (water escape cusps, dish-and-pillar and pocket-and-pillar structures), soft-sediment intrusions (clastic sills and dykes), disturbed laminites, convolute laminations, slumps and synsedimentary faulting. Deformation mechanisms and driving forces are related essentially to gravitational instabilities, dewatering, liquidization and brittle deformations. Field and regional geological data show that most of these deformations are related to seismicity and can be interpreted as seismites. This area has a geological and recent seismic history and outcrops show both syn- and post-depositional faulting related to the transpressional regime of this part of the Colombian Andes, which generates strike-slip faults and associated local normal faults. The drainage pattern within the Zarzal Formation shows the signature of neotectonics. Moreover, the fine to coarse-grained sands of the Zarzal Formation are lithologies prone to liquefaction when affected by seismic waves. The intercalation of the deformed intervals within undisturbed strata confirms the catastrophic nature of the events. Finally, the large areal extent of the deformations and the type of structures are compatible with seismites. Consequently, the existence of seismites in the Zarzal Formation represents corroboration of tectonic activity in this area during the Pleistocene. Earthquakes with a magnitude higher than 5 can be postulated, based upon the proximity of active faults and the types of deformations.

21 CFR 886.4155 - Scleral plug.

Code of Federal Regulations, 2014 CFR

2014-04-01

... stainless steel with or without a gold, silver, or titanium coating. The special controls for the surgical grade stainless steel scleral plug (with or without a gold, silver, or titanium coating) are: (i) The... titanium coating). The special controls for scleral plugs made of other materials are: (i) The device must...

78 FR 70395 - Buy America Waiver Notification

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-25

...--light, medium, and heavy duty plug-in battery electric and compressed natural gas vehicles by Chicago..., medium, and heavy duty plug-in battery electric and compressed natural gas vehicles by Chicago DOT. In...--light, medium, and heavy duty plug-in battery electric and compressed natural gas vehicles ( http://www...

Excess flow shutoff valve

DOEpatents

Kiffer, Micah S.; Tentarelli, Stephen Clyde

2016-02-09

Excess flow shutoff valve comprising a valve body, a valve plug, a partition, and an activation component where the valve plug, the partition, and activation component are disposed within the valve body. A suitable flow restriction is provided to create a pressure difference between the upstream end of the valve plug and the downstream end of the valve plug when fluid flows through the valve body. The pressure difference exceeds a target pressure difference needed to activate the activation component when fluid flow through the valve body is higher than a desired rate, and thereby closes the valve.

Nuclear reactor apparatus

DOEpatents

Wade, Elman E.

1978-01-01

A lifting, rotating and sealing apparatus for nuclear reactors utilizing rotating plugs above the nuclear reactor core. This apparatus permits rotation of the plugs to provide under the plug refueling of a nuclear core. It also provides a means by which positive top core holddown can be utilized. Both of these operations are accomplished by means of the apparatus lifting the top core holddown structure off the nuclear core while stationary, and maintaining this structure in its elevated position during plug rotation. During both of these operations, the interface between the rotating member and its supporting member is sealingly maintained.

Low power integrated pumping and valving arrays for microfluidic systems

DOEpatents

Krulevitch, Peter A [Pleasanton, CA; Benett, William J [Livermore, CA; Rose, Klint A [Livermore, CA; Hamilton, Julie [Tracy, CA; Maghribi, Mariam [Davis, CA

2006-04-11

Low power integrated pumping and valving arrays which provide a revolutionary approach for performing pumping and valving approach for performing pumping and valving operations in microfabricated fluidic systems for applications such as medical diagnostic microchips. Traditional methods rely on external, large pressure sources that defeat the advantages of miniaturization. Previously demonstrated microfabrication devices are power and voltage intensive, only function at sufficient pressure to be broadly applicable. This approach integrates a lower power, high-pressure source with a polymer, ceramic, or metal plug enclosed within a microchannel, analogous to a microsyringe. When the pressure source is activated, the polymer plug slides within the microchannel, pumping the fluid on the opposite side of the plug without allowing fluid to leak around the plug. The plugs also can serve as microvalves.

Nuclear reactor

DOEpatents

Wade, Elman E.

1979-01-01

A nuclear reactor including two rotatable plugs and a positive top core holddown structure. The top core holddown structure is divided into two parts: a small core cover, and a large core cover. The small core cover, and the upper internals associated therewith, are attached to the small rotating plug, and the large core cover, with its associated upper internals, is attached to the large rotating plug. By so splitting the core holddown structures, under-the-plug refueling is accomplished without the necessity of enlarging the reactor pressure vessel to provide a storage space for the core holddown structure during refueling. Additionally, the small and large rotating plugs, and their associated core covers, are arranged such that the separation of the two core covers to permit rotation is accomplished without the installation of complex lifting mechanisms.

Post-stenotic plug-like jet with a vortex ring demonstrated by 4D flow MRI.

PubMed

Kim, Guk Bae; Ha, Hojin; Kweon, Jihoon; Lee, Sang Joon; Kim, Young-Hak; Yang, Dong Hyun; Kim, Namkug

2016-05-01

To investigate the details of the flow structure of a plug-like jet that had a vortex ring in pulsatile stenotic phantoms using 4D flow MRI. Pulsatile Newtonian flows in two stenotic phantoms with 50% and 75% reductions in area were scanned by 4D flow MRI. Blood analog working fluid was circulated via the stenotic phantom using a pulsatile pump at a constant pulsating frequency of 1Hz. The velocity and vorticity fields of the plug-like jet with a vortex ring were quantitatively analyzed in the spatial and temporal domains. Pulsatile stenotic flow showed a plug-like jet at the specific stenotic degree of 50% in our pulsatile waveform design. This plug-like jet was found at the decelerating period in the post-stenotic region of 26.4mm (1.2 D). It revealed a vortex ring structure with vorticity strength in the range of ±100s(-1). We observed a plug-like jet with a vortex ring in pulsatile stenotic flow by in vitro visualization using 4D flow MRI. In this plug-like jet, the local fastest flow region occurred at the post-systole phase in the post-stenotic region, which was distinguishable from a typical stenotic jet flow at systole phase. Copyright © 2015 Elsevier Inc. All rights reserved.

Analyses of sulfonamide antibiotics by a successive anion- and cation-selective injection coupled to microemulsion electrokinetic chromatography.

PubMed

Lin, Yun-Ta; Liu, Yu-Wei; Cheng, Yi-Jie; Huang, Hsi-Ya

2010-07-01

In this study, an MEEKC was used to detect and analyze nine sulfonamide antibiotics. Owing to an insufficient sensitivity of on-column UV detection, a field-amplified sample injection, successive anion- and cation-selective injection, was used for the on-line concentration of the nine antibiotics. In the successive anion- and cation-selective injection mode, a leading water plug was introduced prior to anion injection, and then an acidic plug followed by a terminal water plug had to be used before subsequent cation injection. The results indicated some sulfonamides (sulfamonomethoxine, sulfamethazine, sulfamerazine and sulfadiazine) were determined as split signals in pairs, and this was likely due to the use of a longer acid plug (360 s) which caused the sulfonamide anions and cations to be stacked in two distinct zones of the leading water and acid plugs. Meanwhile, all the sulfonamides that were introduced either by anion or cation injection were stacked within the leading water plug when a shorter acid plug (210 s) was used. As a result, the nine sulfonamides were determined as single and symmetrical peaks with low LODs (0.9-4.2 microg/L). Furthermore, the MEEKC method was successfully applied for the detection of trace sulfonamide residues in several food and water samples.

Formation, Fate, and Impacts of Microscopic and Macroscopic Oil-Sediment Residues in Nearshore Marine Environments: A Critical Review

NASA Astrophysics Data System (ADS)

Gustitus, Sarah A.; Clement, T. Prabhakar

2017-12-01

Crude oil that is spilled in marine environments often interacts with suspended sediments to form residues that can impact the recovery of the affected nearshore ecosystems. When spilled oil and sediment interact, they can form either small microscopic aggregates, commonly referred to as oil-particle aggregates, or large macroscopic agglomerates, referred to as sediment-oil agglomerates or sediment-oil mats. Although these different sized oil-sediment residues have similar compositions, they are formed under different conditions and have different fates in nearshore environments; the goal of this review is to synthesize our current understanding of these two types of residues. We believe that researchers who focus solely on studying either microscopic aggregates or macroscopic agglomerates could benefit from understanding the research findings available in the other field. In this study, we compare and contrast various processes that control the formation, fate, and impacts of these two types of residues in nearshore environments and point out some of the knowledge gaps in this field. Additionally, these residues have been referred to by many names in the past, leading to confusion and misconceptions at times. In this effort, we recommend a uniform nomenclature to distinguish them based on their physical size. Our overall aim is to bridge the gap between microscopic and macroscopic oil-sediment residue literature to foster a robust exchange of ideas, which we believe can lead to the development of efficient strategies for managing oil spills that affect nearshore environments.

Technical Report for Proposed Ordnance Clearance at Fort George G. Meade

DTIC Science & Technology

1991-03-01

Potomac Group (including the Patapsco, Arundel Clay, and Patuxent Formations), the Magothy Formation and the Patuxent River terraces and associated...alluvium. The youngest geologic unit in theI stratigraphic sequence underlying Fort Meade is the Magothy Formation of Late Cretaceous age. This formation...Department of the Army, 1981). The Magothy Formation unconformably overlies the sediments of the Lower Cretaceous Potomac Group. i The formations of the

The ERG Science Center

NASA Astrophysics Data System (ADS)

Miyoshi, Yoshizumi; Hori, Tomoaki; Shoji, Masafumi; Teramoto, Mariko; Chang, T. F.; Segawa, Tomonori; Umemura, Norio; Matsuda, Shoya; Kurita, Satoshi; Keika, Kunihiro; Miyashita, Yukinaga; Seki, Kanako; Tanaka, Yoshimasa; Nishitani, Nozomu; Kasahara, Satoshi; Yokota, Shoichiro; Matsuoka, Ayako; Kasahara, Yoshiya; Asamura, Kazushi; Takashima, Takeshi; Shinohara, Iku

2018-06-01

The Exploration of energization and Radiation in Geospace (ERG) Science Center serves as a hub of the ERG project, providing data files in a common format and developing the space physics environment data analysis software and plug-ins for data analysis. The Science Center also develops observation plans for the ERG (Arase) satellite according to the science strategy of the project. Conjugate observations with other satellites and ground-based observations are also planned. These tasks contribute to the ERG project by achieving quick analysis and well-organized conjugate ERG satellite and ground-based observations.

Physical stratigraphy, paleontology, and magnetostratigraphy of the USGS-Santee Coastal Reserve core (CHN-803), Charleston County, South Carolina

USGS Publications Warehouse

Edwards, Lucy E.; Gohn, G.S.; ,; Prowell, D.C.; Bybell, L.M.; Bardot, L.P.; Firth, J.V.; Huber, B.T.; Frederiksen, N.O.; MacLeod, K.G.

1999-01-01

The Santee Coastal Reserve core, a 545-ft-deep corehole in northeastern Charleston County, South Carolina, recovered sediments of Late Cretaceous, Paleocene, Eocene, and Quaternary age. The deepest sediments, the Donoho Creek Formation (545-475.7 ft), consist of 69.3 ft of muddy calcareous sand of marine origin. This formation is placed within the upper Campanian calcareous nannofossil Subzone CC 22c. The overlying Peedee Formation (475.7-367.1 ft) in the core consists of 108.6 ft of silty clay of marine origin. It is placed in upper Maastrichtian calcareous nannofossil Subzones CC 25b, CC 26a, and CC 26b. Combined fossil and paleomagnetic information indicates nearly continuous deposition. Foraminifers indicate an outer neritic paleobathymetric setting. The Rhems Formation sensu stricto (367.1-267.3 ft) consists of 99.8 ft of silty clay, muddy sand, and minor calcite-cemented, shelly sand of marine origin. It is apparently the product of rapid sediment accumulation during a short period of time in the early Paleocene (calcareous nannofossil Zone NP 1). The upper part of the Rhems Formation sensu Bybell and others (1998) (267.3-237.4 ft) consists of 29.9 ft of calcite-cemented muddy sand and burrowed fine sand of marine origin. It is placed in calcareous nannofossil Zone NP 4 and, because it shows normal polarity, likely represents the upper part of the lower Paleocene. This unit may be correlative with the lower part of the Lower Bridge Member of the Williamsburg Formation in its type area. The Lower Bridge Member of the Williamsburg Formation (237.4-125.0 ft) has an unconformable contact at 205.0 ft that divides the member into lower muddy sand beds and upper calcareous clay beds. Both are placed in the upper Paleocene calcareous nannofossil Zone NP 5. The Chicora Member of the Williamsburg Formation (125-51.5 ft) consists of 73.5 ft of muddy, shelly sand of marine origin. It is poorly dated but includes late Paleocene nannofossils (Zones NP 5 and NP 6). A mollusk-bryozoan limestone (51.5-42.0 ft) above the Chicora Member of the Williamsburg yields early Eocene calcareous nannofossils representing both Zone NP 9/10 and Zone NP 12, together with pollen and dinocysts that are younger. Sediments of middle and late Eocene, Oligocene, Miocene, and Pliocene ages were not recovered in the Santee Coastal Reserve core. The upper 42.0 ft of sediments represent Quaternary deposits and are included in the Wando Formation (42.0-28.0 ft) and the informal Silver Bluff beds (28.0-0 ft).

On water in volcanic clouds

NASA Astrophysics Data System (ADS)

Durant, Adam J.

2007-12-01

Volcanic clouds and tephra fallout present a hazard to aviation, human and animal health (direct inhalation or ingestion, contamination of water supplies), and infrastructure (building collapse, burial of roads and railways, agriculture, abrasive and chemical effects on machinery). Understanding sedimentation processes is a fundamental component in the prediction of volcanic cloud lifetime and fallout at the ground, essential in the mitigation of these hazards. The majority of classical volcanic ash transport and dispersion models (VATDM) are based solely on fluid dynamics. The non-agreement between VATDM and observed regional-scale tephra deposit characteristics is especially obvious at large distances from the source volcano. In meteorology, the processes of hydrometeor nucleation, growth and collection have been long-established as playing a central role in sedimentation and precipitation. Taking this as motivation, the hypothesis that hydrometeor formation drives sedimentation from volcanic clouds was tested. The research objectives of this dissertation are: (1) To determine the effectiveness of tephra particles in the catalysis of the liquid water to ice phase transformation, with application to ice hydrometeor formation in volcanic clouds. (2) To determine the sedimentological characteristics of distal (100s km) tephra fallout from recent volcanic clouds. (3) To assess particle fallout rates from recent volcanic clouds in the context of observed deposit characteristics. (4) To assess the implications of hydrometeor formation on the enhancement of volcanic sedimentation and the potential for cloud destabilization from volcanic hydrometeor sublimation. Dissertation Overview. The following chapters present the analysis, results and conclusions of heterogeneous ice nucleation experiments and sedimentological characterization of several recent tephra deposits. The dissertation is organized in three chapters, each prepared in journal article format. In Chapter 1, single ash particle freezing experiments were carried out to investigate the effect of ash particle composition and surface area on water drop freezing temperature. In Chapter 2, the tephra deposit from the 18 May 1980 eruption of Mount St. Helens, USA, was reanalyzed using laser diffraction particle size analysis and hydrometeor-induced sedimentation mechanisms are considered. In Chapter 3, fallout from the 18 August 1992 and 16--17 September 1992 eruptions of Mount Spurr, USA, was analyzed and particle sedimentation and cloud microphysics were modeled to assess the potential for cloud destabilization from hydrometeor sublimation.

Flow, Sediment Supply, and Channel Width Controls on Gravel Bedform Dynamics

NASA Astrophysics Data System (ADS)

Nelson, P. A.; Morgan, J. A.

2017-12-01

Heterogeneous, coarse-grained riverbeds often self-organize into migrating bedforms such as gravel dunes or bedload sheets. It has recently been suggested that sediment supply and the relative mobility of the bed surface sediment affects the type of bedforms that may be present in gravel-bed rivers; however, our understanding of gravel bedform dynamics remains well behind that of bedforms in sandy channels. Here, we present results from flume experiments in which we investigate how the formation and dynamics of gravel bedforms is affected by changes in discharge, sediment supply, and channel geometry. Experiments were conducted in a 1.1-m wide, 18-m long, sediment-feed flume. The initial bed material and the sediment feed mixture was composed of a sediment mixture ranging in size from 0.5-4 mm, with a median value of 3.6 mm. We used two channel geometries (a straight channel and a channel with sinusoidal width variations) and conducted three experimental runs for each geometry: 1) equilibrium sediment supply and steady flow, 2) equilibrium sediment supply and repeated hydrographs, and 3) doubled sediment supply and repeated hydrographs. During the experiments, low-amplitude, migrating bedforms developed and their dynamics were tracked both visually and via collection of repeated structure-from-motion topographic datasets. In the constant-width geometry, bedform amplitudes and migration rates were relatively constant under steady flow, but when subjected to repeated hydrographs the average bedform celerity decreased by about 50% and the amplitude of the bedforms increased and decreased with the changing flow rate. At twice the equilibrium sediment supply, the bedforms organized into an alternating pattern. This pattern was most pronounced at the lower flow rates, and became less stable at the higher discharges of the repeat hydrographs. Preliminary results suggest bedform celerity in the variable width geometry under steady flow and equilibrium sediment supply was half the celerity of the bedforms for the same conditions in the straight-walled geometry. These experiments suggest that variations in discharge, sediment supply, and channel geometry play an important role in the formation and dynamics of bedforms in gravel-bed rivers.

Tectonic Processes Along the Southeastern Margin of Alaska - The Neogene Sedimentary Record: Yakataga Formation, St. Elias Mountains

NASA Astrophysics Data System (ADS)

Witmer, J. W.; Ridgway, K. D.; Brennan, P. R.; Arnaud, E.; Pavlis, T.

2008-12-01

Neogene collision of the Yakutat microplate with the southern Alaskan continental margin is associated with extreme rates of exhumation and erosion of the St. Elias Mountains. The exhumation and the concurrent development of temperate glaciers are recorded in the ~5000 m of sedimentary strata of the Yakataga Formation. We present new data from measured stratigraphic sections that document along-strike and temporal changes within the Yakataga Formation along this collisional margin during Miocene to Pleistocene time. In the eastern part of our study area, the Yakataga Formation consists of lenticular sandstone and conglomerate facies associated with fan-delta depositional environments that are overlain by thick-bedded glaciomarine strata. These strata grade to finer-grained sandstone and convoluted mudstone typical of marine shelf environments in the central part of our study area. Along strike in the westernmost part of our study area the Yakataga Formation is interpreted to be laterally equivalent to Neogene strata of the Redwood Formation. These strata include thick-bedded, macrofossil-rich sandstone, well-rounded conglomerate, and thin-bedded mudstone facies that are characteristic of nearshore and shelf depositional environments. These sediments were likely sourced by fluvial systems along the continental margin that served as the backstop for Neogene collision. Preliminary compositional data also suggest that the Redwood Formation was derived from a different source than the Yakataga Formation. Along-strike changes in structural configuration of the Yakataga Formation are also observed. In the easternmost part of our study area adjacent to the Dangerous River zone (DRZ), a possible remnant strike-slip fault system, unconformities between the Yakataga Formation and underlying strata require erosion of 1000s of meters of missing Eocene-Miocene strata. We interpret this part of the mountain range to have undergone the greatest amount of Neogene exhumation. In the central part of the study area, the Yakataga Formation is exposed in a series of growth folds and megachannels that have been incorporated into a southward-propagating thrust belt as sediment was transported westward away from the exhuming St. Elias Range. To the west, more complete stratigraphic sections and finer-grained lithofacies suggest relatively less syndepositional deformation during the deposition of the Yakataga Formation. From a stratigraphic perspective, the DRZ appears to have focused deformation, exhumation, development of temperate glaciers, and westward transport of sediment during deposition of the Yakataga Formation. The westward changes in lithofacies and deformation within the Yakataga Formation are interpreted as products of progressive oblique collision of the Yakutat microplate to the southeastern Alaskan continental margin. New U-Pb detrital zircon geochronologic data from the Yakataga Formation and older underlying strata demonstrate minimal changes in provenance from Eocene to Pleistocene time. We interpret these data to reflect recycling of sediment within the collisional zone.

Mesoarchean black shale -iron sedimentary sequences in Cleaverville Formation, Pilbara Australia: drilling preliminary result of DXCL2

NASA Astrophysics Data System (ADS)

Kiyokawa, S.; Ito, T.; Ikehara, M.; Yamaguchi, K. E.; Onoue, T.; Horie, K.; Sakamoto, R.; Teraji, S.; Aihara, Y.

2012-12-01

The 3.2-3.1 Ga Dixon island-Cleaverville formations are well-preserved hydrothermal oceanic sequence at oceanic island arc setting (Kiyokawa et al., 2002, 2006, 2012). The Dixon Island (3195+15 Ma) - Cleaverville (3108+13 Ma) formations formed volcano-sedimentary sequences with hydrothermal chert, black shale and banded iron formation to the top. Based on the scientific drilling as DXCL1 at 2007 and DXCL2 at 2011, lithology was clearly understood. Four drilling holes had been done at coastal sites; the Dixon Island Formation is DX site (100m) and the Cleaverville Formation is CL2 (40m), CL1 (60m) and CL3 (200m) sites and from stratigraphic bottom to top. These sequences formed coarsening and thickening upward black shale-BIF sequences. The Dixon Island Formation consists komatiite-rhyolite sequences with many hydrothermal veins and very fine laminated cherty rocks above them. The Cleaverville Formation contains black shale, fragments-bearing pyroclastic beds, white chert, greenish shale and BIF. Especially, CL3 core, which drilled through the Iron formation, shows siderite-chert beds above black shale identified before magnetite lamination bed. The magnetite bed formed very thin laminated bed with siderite lamination. This magnetite bed was covered by black shale beds again. New U-Pb SHRIMP data of the pyroclastic in black shale is 3109Ma. Estimated 2-8 cm/1000year sedimentation rate are identified in these sequences. Our preliminary result show that siderite and chert layers formed before magnetite iron sedimentation. The lower-upper sequence of organic carbon rich black shales are similar amount of organic content and 13C isotope (around -30per mill). So we investigate that the Archean iron formation, especially Cleaverville iron formation, was highly related by hydrothermal input and started pre-syn iron sedimentation at anoxic oceanic condition.

Age and correlation of tertiary sediments in the western South Carolina Coastal Plain

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

Laws, R.A.; Harris, W.B.; Zullo, V.A.

1987-01-01

Integration of coastal onlap stratigraphy, calcareous nannofossil, dinoflagellate, and megafossil biostratigraphy provide new data for interpretation of age and interregional correlation of Paleocene to Oligocene deposits of the western South Carolina Coastal Plain. Clastic and calcareous sediments examined in cores and outcrops in the vicinity of the Savannah River Plant record at least seven coastal onlap cycles. Basal Tertiary sediments of the Ellenton Formation represent cycles TA1.1 - 1.3 and contain dinoflagellates of Midwayan to Sabinian age. The overlying Williamsburg Formation probably represents deposits of cycle TA2.1. The superjacent siliciclastics of the Congaree Formation contain few fossils, but may preservemore » transgressive and highstand deposits of cycles TA2.4 - 3.3. The overlying unit is commonly calcareous, contains nannofossils indicative of zones NP16-17 (Upper Claibornian), and marks a significant change in depositional style subsequent to the 49.5 Ma eustatic fall. ''Marls'' of the overlying Griffins Landing Member of the Dry Branch Formation contain micro- and megafossils of Late Eocene (Jacksonian) age and represent transgressive deposits of cycle TA4.1. The discontinuous lateral distribution of these calcareous units and overlying clastics of the Dry Branch and Tobacco Road Formations results largely from erosion and deep incision during the mid-Oligocene eustatic fall (30 Ma). The ''Upland'' unit is interpreted as being deposited on this erosional surface.« less

Gas-controlled seafloor doming on Opouawe Bank, offshore New Zealand

NASA Astrophysics Data System (ADS)

Koch, Stephanie; Berndt, Christian; Bialas, Joerg; Haeckel, Matthias; Crutchley, Gareth; Papenberg, Cord; Klaeschen, Dirk; Greinert, Jens

2015-04-01

The process of gas accumulation and subsequent sediment doming appears to be a precursory process in the development of methane seep sites on Opouawe Bank and might be a common characteristic for gas seeps in general. Seabed domes appear as unimpressive topographic highs with diameters ranging from 10-1000 m and exhibit small vertical displacements and layer thickness in comparison to their width. The dome-like uplift of the sediments results from an increase in pore pressure caused by gas accumulation in near-seabed sediments. In this context sediment doming is widely discussed to be a precursor of pockmark formation. Our results suggest that by breaching of domed seafloor sediments a new seep site can develop and contrary to ongoing discussion does not necessarily lead to the formation of pockmarks. There are clear differences in individual gas migration structures that indicate a progression through different evolutionary stages, which range from channeled gas flow and associated seismic blanking, to gas trapping beneath relatively low-permeability horizons, and finally overpressure accumulation and doming. We present high resolution sub-bottom profiler (Parasound) and 2D multichannel seismic data from Opouawe Bank, an accretionary ridge at the Hikurangi Margin, offshore New Zealand's North Island. Beneath this bank, methane migrates along stratigraphic pathways from a maximum source depth of 1500-2100 mbsf (meter below seafloor) towards active cold seeps at the seafloor. We show that, in the shallow sediment of the upper 100 mbsf, this primary migration mechanism changes into a process of gas accumulation leading to sediment doming. Modeling the height of the gas column necessary to create different dome geometries, shows that doming due to gas accumulation is feasible and consistent with field observations. The well-stratified, sub-horizontal strata that exist beneath Opouawe Bank provide favorable conditions for this type of seep development because shallow sub-vertical gas migration is forced to traverse sedimentary layering in the absence of faults that might otherwise have provided more efficient gas migration pathways. Thus, gas has to generate its own migration pathways through the progressive process of doming and breaking through the strata. The data from offshore New Zealand document that shallow sediment doming does not have to be associated with seafloor pockmarks and that models in which fluid migration through soft sediments necessarily culminates in pockmark formations are not applicable everywhere.

Unit: Rocks from Sediments, Inspection Pack, National Trial Print.

ERIC Educational Resources Information Center

Australian Science Education Project, Toorak, Victoria.

Four compulsory introductory activities, involving learning to use a stream tray, observing the relationship between water speed and entraining, transporting and depositing sediments, studying the formation of sedimentary rocks, and examining several types of sedimentary rocks, are completed by all students using the unit prepared for Australian…

Unit: Rocks from Sediments, Inspection Set, First Trial Materials.

ERIC Educational Resources Information Center

Australian Science Education Project, Toorak, Victoria.

Four compulsory introductory activities involving learning to use a stream tray, observing the relationship between water speed and entraining, transporting and depositing sediments, studying the formation of sedimentary rocks, and examining several types of sedimentary rocks are completed by all students using the unit prepared for Australian…

Insights into the origin and characteristics of the sedimentation process at multi-barrel culverts in Iowa : technical transfer summary.

DOT National Transportation Integrated Search

2010-06-01

The present study is an integral part of a : broader study focused on the design and : implementation of self-cleaning culverts, i.e., : configurations that prevent the formation of : sediment deposits after culvert construction or : cleaning. Sedime...

Evaluation Of Selected Sorption Materials For Capping Mercury-Contaminated Fresh Water Sediments

EPA Science Inventory

Fate and transport of mercury (Hg) and methylmercury (MeHg) within the aquatic environment involves many complex and interconnected pathways. MeHg is formed mainly at the sediment-water interface, just below which there is a transition from oxic to anoxic conditions. The format...

A Photo Storm Report Mobile Application, Processing/Distribution System, and AWIPS-II Display Concept

NASA Astrophysics Data System (ADS)

Longmore, S. P.; Bikos, D.; Szoke, E.; Miller, S. D.; Brummer, R.; Lindsey, D. T.; Hillger, D.

2014-12-01

The increasing use of mobile phones equipped with digital cameras and the ability to post images and information to the Internet in real-time has significantly improved the ability to report events almost instantaneously. In the context of severe weather reports, a representative digital image conveys significantly more information than a simple text or phone relayed report to a weather forecaster issuing severe weather warnings. It also allows the forecaster to reasonably discern the validity and quality of a storm report. Posting geo-located, time stamped storm report photographs utilizing a mobile phone application to NWS social media weather forecast office pages has generated recent positive feedback from forecasters. Building upon this feedback, this discussion advances the concept, development, and implementation of a formalized Photo Storm Report (PSR) mobile application, processing and distribution system and Advanced Weather Interactive Processing System II (AWIPS-II) plug-in display software.The PSR system would be composed of three core components: i) a mobile phone application, ii) a processing and distribution software and hardware system, and iii) AWIPS-II data, exchange and visualization plug-in software. i) The mobile phone application would allow web-registered users to send geo-location, view direction, and time stamped PSRs along with severe weather type and comments to the processing and distribution servers. ii) The servers would receive PSRs, convert images and information to NWS network bandwidth manageable sizes in an AWIPS-II data format, distribute them on the NWS data communications network, and archive the original PSRs for possible future research datasets. iii) The AWIPS-II data and exchange plug-ins would archive PSRs, and the visualization plug-in would display PSR locations, times and directions by hour, similar to surface observations. Hovering on individual PSRs would reveal photo thumbnails and clicking on them would display the full resolution photograph.Here, we present initial NWS forecaster feedback received from social media posted PSRs, motivating the possible advantages of PSRs within AWIPS-II, the details of developing and implementing a PSR system, and possible future applications beyond severe weather reports and AWIPS-II.