Use of overburden rocks from open-pit coal mines and waste coals of Western Siberia for ceramic brick production with a defect-free structure

NASA Astrophysics Data System (ADS)

Stolboushkin, A. Yu; Ivanov, A. I.; Storozhenko, G. I.; Syromyasov, V. A.; Akst, D. V.

2017-09-01

The rational technology for the production of ceramic bricks with a defect-free structure from coal mining and processing wastes was developed. The results of comparison of physical and mechanical properties and the structure of ceramic bricks manufactured from overburden rocks and waste coal with traditional for semi-dry pressing mass preparation and according to the developed method are given. It was established that a homogeneous, defect-free brick texture obtained from overburden rocks of open-pit mines and waste coal improves the quality of ceramic wall materials produced by the method of compression molding by more than 1.5 times compared to the brick with a traditional mass preparation.

Rational Use of Land Resource During the Implementation of Transportless System of Coal Strata Surface Mining

NASA Astrophysics Data System (ADS)

Gvozdkova, T.; Tyulenev, M.; Zhironkin, S.; Trifonov, V. A.; Osipov, Yu M.

2017-01-01

Surface mining and open pits engineering affect the environment in a very negative way. Among other pollutions that open pits make during mineral deposits exploiting, particular problem is the landscape changing. Along with converting the land into pits, surface mining is connected with pilling dumps that occupy large ground. The article describes an analysis of transportless methods of several coal seams strata surface mining, applied for open pits of South Kuzbass coal enterprises (Western Siberia, Russia). To improve land-use management of open pit mining enterprises, the characteristics of transportless technological schemes for several coal seams strata surface mining are highlighted and observed. These characteristics help to systematize transportless open mining technologies using common criteria that characterize structure of the bottom part of a strata and internal dumping schemes. The schemes of transportless systems of coal strata surface mining implemented in South Kuzbass are given.

General and crevice corrosion study of the in-wall shielding materials for ITER vacuum vessel

NASA Astrophysics Data System (ADS)

Joshi, K. S.; Pathak, H. A.; Dayal, R. K.; Bafna, V. K.; Kimihiro, Ioki; Barabash, V.

2012-11-01

Vacuum vessel In-Wall Shield (IWS) will be inserted between the inner and outer shells of the ITER vacuum vessel. The behaviour of IWS in the vacuum vessel especially concerning the susceptibility to crevice of shielding block assemblies could cause rapid and extensive corrosion attacks. Even galvanic corrosion may be due to different metals in same electrolyte. IWS blocks are not accessible until life of the machine after closing of vacuum vessel. Hence, it is necessary to study the susceptibility of IWS materials to general corrosion and crevice corrosion under operations of ITER vacuum vessel. Corrosion properties of IWS materials were studied by using (i) Immersion technique and (ii) Electro-chemical Polarization techniques. All the sample materials were subjected to a series of examinations before and after immersion test, like Loss/Gain weight measurement, SEM analysis, and Optical stereo microscopy, measurement of surface profile and hardness of materials. After immersion test, SS 304B4 and SS 304B7 showed slight weight gain which indicate oxide layer formation on the surface of coupons. The SS 430 material showed negligible weight loss which indicates mild general corrosion effect. On visual observation with SEM and Metallography, all material showed pitting corrosion attack. All sample materials were subjected to series of measurements like Open Circuit potential, Cyclic polarization, Pitting potential, protection potential, Critical anodic current and SEM examination. All materials show pitting loop in OC2 operating condition. However, its absence in OC1 operating condition clearly indicates the activity of chloride ion to penetrate oxide layer on the sample surface, at higher temperature. The critical pitting temperature of all samples remains between 100° and 200°C.

Testing and modeling the influence of reclamation and control methods for reducing nonpoint mercury emissions associated with industrial open pit gold mines.

PubMed

Miller, Matthieu B; Gustin, Mae S

2013-06-01

Industrial gold mining is a significant source of mercury (Hg) emission to the atmosphere. To investigate ways to reduce these emissions, reclamation and dust and mercury control methods used at open pit gold mining operations in Nevada were studied in a laboratory setting. Using this information along with field data, and building off previous work, total annual Hg emissions were estimated for two active gold mines in northern Nevada. Results showed that capping mining waste materials with a low-Hg substrate can reduce Hg emissions from 50 to nearly 100%. The spraying of typical dust control solutions often results in higher Hg emissions, especially as materials dry after application. The concentrated application of a dithiocarbamate Hg control reagent appears to reduce Hg emissions, but further testing mimicking the actual distribution of this chemical within an active leach solution is needed to make a more definitive assessment.

Retaining latch for a water pit gate

DOEpatents

Beale, A.R.

1997-11-18

A retaining latch is described for use in a hazardous materials storage or handling facility to adjustably retain a water pit gate in a gate frame. A retaining latch is provided comprising a latch plate which is rotatably mounted to each end of the top of the gate and a recessed opening, formed in the gate frame, for engaging an edge of the latch plate. The latch plate is circular in profile with one side cut away or flat, such that the latch plate is D-shaped. The remaining circular edge of the latch plate comprises steps of successively reduced thickness. The stepped edge of the latch plate fits inside a recessed opening formed in the gate frame. As the latch plate is rotated, alternate steps of the latch plate are engaged by the recessed opening. When the latch plate is rotated such that the flat portion of the latch plate faces the recessed opening in the gate frame, there is no connection between the opening and the latch plate and the gate is unlatched from the gate frame. 4 figs.

78 FR 33894 - Proposed Information Collection (Open Burn Pit Registry Airborne Hazard Self-Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-05

... Burn Pit Registry Airborne Hazard Self-Assessment Questionnaire) Activity: Comment Request AGENCY... ascertain and monitor the health effects of the exposure of members of the Armed Forces to toxic airborne... to ``OMB Control No. 2900-NEW, Open Burn Pit Registry Airborne Hazard Self-Assessment Questionnaire...

Burn Pit Emissions Exposure and Respiratory and Cardiovascular Conditions Among Airborne Hazards and Open Burn Pit Registry Participants.

PubMed

Liu, Jason; Lezama, Nicholas; Gasper, Joseph; Kawata, Jennifer; Morley, Sybil; Helmer, Drew; Ciminera, Paul

2016-07-01

The aim of this study was to determine how burn pit emissions exposure is associated with the incidence of respiratory and cardiovascular conditions. We examined the associations between assumed geographic and self-reported burn pit emissions exposure and respiratory and cardiovascular outcomes in participants of the Airborne Hazards and Open Burn Pit Registry. We found significant dose-response associations for higher risk of self-reported emphysema, chronic bronchitis, or chronic obstructive pulmonary disease with increased days of deployment within 2 miles of selected burn pits (P-trend = 0.01) and self-reported burn pit smoke exposure (P-trend = 0.0005). We found associations between burn pit emissions exposure and higher incidence of post-deployment self-reported respiratory and cardiovascular conditions, but these findings should be interpreted with caution because the surrogate measurements of burn pit emissions exposure in this analysis may not reflect individual exposure levels.

49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

Code of Federal Regulations, 2010 CFR

2010-10-01

... vault or pit is sealed, each opening must have a tight fitting cover without open holes through which an... Components § 192.187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed top pit....7 cubic meters): (1) The vault or pit must be ventilated with two ducts, each having at least the...

Ultimate open pit stochastic optimization

NASA Astrophysics Data System (ADS)

Marcotte, Denis; Caron, Josiane

2013-02-01

Classical open pit optimization (maximum closure problem) is made on block estimates, without directly considering the block grades uncertainty. We propose an alternative approach of stochastic optimization. The stochastic optimization is taken as the optimal pit computed on the block expected profits, rather than expected grades, computed from a series of conditional simulations. The stochastic optimization generates, by construction, larger ore and waste tonnages than the classical optimization. Contrary to the classical approach, the stochastic optimization is conditionally unbiased for the realized profit given the predicted profit. A series of simulated deposits with different variograms are used to compare the stochastic approach, the classical approach and the simulated approach that maximizes expected profit among simulated designs. Profits obtained with the stochastic optimization are generally larger than the classical or simulated pit. The main factor controlling the relative gain of stochastic optimization compared to classical approach and simulated pit is shown to be the information level as measured by the boreholes spacing/range ratio. The relative gains of the stochastic approach over the classical approach increase with the treatment costs but decrease with mining costs. The relative gains of the stochastic approach over the simulated pit approach increase both with the treatment and mining costs. At early stages of an open pit project, when uncertainty is large, the stochastic optimization approach appears preferable to the classical approach or the simulated pit approach for fair comparison of the values of alternative projects and for the initial design and planning of the open pit.

Structure of energy consumption and improving open-pit dump truck efficiency

NASA Astrophysics Data System (ADS)

Koptev, V. Yu; Kopteva, A. V.

2017-10-01

This paper studies the dynamics of the improvement of wheel type transport vehicles environmental and energy performance in open-pit mines. The paper discloses characteristics of the gas turbine engine with capacity of 1250 hp, mounted on tanks, and technical-economic calculations, confirming reasonability of their use in open-pit dump trucks with the 120 …130-ton loading capacity. The general layout scheme of mechanical transmission with the gas turbine engine is shown.

Near-Field Microwave Detection of Corrosion Precursor Pitting under Thin Dielectric Coatings in Metallic Substrate

NASA Astrophysics Data System (ADS)

Hughes, D.; Zoughi, R.; Austin, R.; Wood, N.; Engelbart, R.

2003-03-01

Detection of corrosion precursor pitting on metallic surfaces under various coatings and on bare metal is of keen interest in evaluation of aircraft fuselage. Near-field microwave nondestructive testing methods, utilizing open-ended rectangular waveguides and coaxial probes, have been used extensively for detection of surface flaws in metals, both on bare metal and under a dielectric coating. This paper presents the preliminary results of using microwave techniques to detect corrosion precursor pitting under paint and primer, applique and on bare metal. Machined pits of 500 μm diameter were detected using open-ended rectangular waveguides at V-Band under paint and primer and applique, and on bare metal. Using coaxial probes, machined pits with diameters down to 150 μm on bare metal were also detected. Relative pit size and density were shown on a corrosion-pitted sample using open-ended rectangular waveguides at frequencies of 35 GHz to 70 GHz. The use of Boeing's MAUS™ scanning systems provided improved results by alleviating standoff variation and scanning artifact. Typical results of this investigation are also presented.

The Experience of Implementation of Innovative Technology of Quarry Waste Water Purifying in Kuzbass Open Pit

NASA Astrophysics Data System (ADS)

Lesin, Yu V.; Hellmer, M. C.

2016-08-01

Among all industries in Kuzbass (Western Siberia, Russia) the coal industry provides the most environmental threat. However, the construction of new and maintenance of existing open pit mines do not often correspond to the tasks of improving the environmental safety of surface mining. So the article describes the use of innovative quarry waste water purifying technology implemented in Kuzbass open pit mine «Shestaki». This technology is based on using artificial filter arrays made of overburden rock.

Case history of controlling a landslide at Panluo open-pit mine in China

NASA Astrophysics Data System (ADS)

Wei, Zuoan; Yin, Guangzhi; Wan, Ling; Shen, Louyan

2008-04-01

Controlling of landsides safely and economically is a great challenge to mine operators because landslides are major geological problems especially in open-pit mines. In this paper, a case history at Panluo open-pit mine is presented in detail to share the experiences and lessons with mine operators. Panluo open-pit mine is located in the southwestern Fujian province of China. It is the largest open-pit iron mine in the Fujian province and was planned in 1965 and is in full operation from 1978. In July 1990, an earthquake of magnitude 5.3 in Taiwan Strait and big rainstorms impacted the mine slope, causing tension cracks and rather large-scale failures, and forming a U-shaped landslide. Total potential volume was estimated to be up to 1.0 × 106 m3. This directly threatened the mine production. In order to protect the mine production and the dwellers’ safety around, a dynamic comprehensive method was implemented including geotechnical investigations, in-situ testing and monitoring, stability analysis, and many mitigation and preventive measures. These measures slowed down the development and further occurrence of the landslide. The results showed that the landslides were still active, it was slowed with the control measures and moved rapidly with rainfall and mining down. However, no catastrophic accidents occurred and the pit mining was continued till it was closed at the elevation of 887 m in 2000. As a successful case of landslide control at an open-pit mine for 10 years, this paper reports the controlling measures in details. These experiences of landslide control may be beneficial to other similar mines for landslide control.

Birth outcomes among military personnel after exposure to documented open-air burn pits before and during pregnancy.

PubMed

Conlin, Ava Marie S; DeScisciolo, Connie; Sevick, Carter J; Bukowinski, Anna T; Phillips, Christopher J; Smith, Tyler C

2012-06-01

To examine birth outcomes in military women and men with potential exposure to documented open-air burn pits before and during pregnancy. Electronic data from the Department of Defense Birth and Infant Health Registry and the Defense Manpower Data Center were used to examine the prevalence of birth defects and preterm birth among infants of active-duty women and men who were deployed within a 3-mile radius of a documented open-air burn pit before or during pregnancy. In general, burn pit exposure at various times in relation to pregnancy and for differing durations was not consistently associated with an increase in birth defects or preterm birth in infants of active-duty military personnel. These analyses offer reassurance to service members that burn pit exposure is not consistently associated with these select adverse infant health outcomes.

Tectonic fault monitoring at open pit mine at Zarnitsa Kimberlite Pipe

NASA Astrophysics Data System (ADS)

Vostrikov, VI; Polotnyanko, NS; Trofimov, AS; Potaka, AA

2018-03-01

The article describes application of Karier instrumentation designed at the Institute of Mining to study fracture formation in rocks. The instrumentation composed of three sensors was used to control widening of a tectonic fault intersecting an open pit mine at Zarnitsa Kimberlite Pipe in Yakutia. The monitoring between 28 November and 28 December in 2016 recorded convergence of the fault walls from one side of the open pit mine and widening from the other side. After production blasts, the fault first grows in width and then recovers.

Efficiency of Low-Profile External Dumping at Open Pit Coal Mining in Kemerovo Region

NASA Astrophysics Data System (ADS)

Selyukov, Alexey; Ermolaev, Vyacheslav; Kostinez, Irina

2017-11-01

Kemerovo region is one of the largest industrial regions of Russia, with a raw material specialization. The rapid growth of the coal industry in recent years has been greatly facilitated by the expansion and development of open pit mining for coal seams extraction, accompanied by an increase in the volumes of overburden and the height of the dumps. There are about 400 objects in the Russian Federation Government Register of Waste Disposal Facilities 80% of which are dumps. Approaches both to external dumping and to the technical stage of reclamation currently contribute to the growth of geomorphic system's instability. Thus, it is proposed to slightly change the approaches to external dumping: the essence consists in the formation of an external dump of overburden, which in future would represent a favorable landscape unit of a flat surface relief used for subsequent differently directed purposes.

Millennium Open Pit Mine, Alberta, Canada

NASA Image and Video Library

2007-11-26

Near Fort McMurray, Alberta, Canada, on the east bank of the Athabasca River, are found the Steepbank and Millennium open pit mines. These images were acquired by NASA Terra satellite on September 22, 2000 and July 31, 2007.

Evaluation of modified crystal violet chromoendoscopy procedure using new mucosal pit pattern classification for detection of Barrett's dysplastic lesions.

PubMed

Yuki, T; Amano, Y; Kushiyama, Y; Takahashi, Y; Ose, T; Moriyama, I; Fukuhara, H; Ishimura, N; Koshino, K; Furuta, K; Ishihara, S; Adachi, K; Kinoshita, Y

2006-05-01

Pit pattern diagnosis is important for endoscopic detection of dysplastic Barrett's lesions, though using magnification endoscopy can be difficult and laborious. We investigated the usefulness of a modified crystal violet chromoendoscopy procedure and utilised a new pit pattern classification for diagnosis of dysplastic Barrett's lesions. A total of 1,030 patients suspected of having a columnar lined oesophagus were examined, of whom 816 demonstrated a crystal violet-stained columnar lined oesophagus. The early group of patients underwent 0.05% crystal violet chromoendoscopy, while the later group was examined using 0.03% crystal violet with 3.0% acetate. A targeted biopsy of the columnar lined oesophagus was performed using crystal violet staining after making a diagnosis of closed or open type pit pattern with a newly proposed system of classification. The relationship between type of pit pattern and histologically identified dysplastic Barrett's lesions was evaluated. Dysplastic Barrett's lesions were identified in biopsy samples with an open type pit pattern with a sensitivity of 96.0%. Further, Barrett's mucosa with the intestinal predominant mucin phenotype was closely associated with the open type pit pattern (sensitivity 81.9%, specificity 95.6%). The new pit pattern classification for diagnosis of Barrett's mucosa was found to be useful for identification of cases with dysplastic lesions and possible malignant potential using a crystal violet chromoendoscopic procedure.

Interference effects in laser-induced plasma emission from surface-bound metal micro-particles

DOE PAGES

Feigenbaum, Eyal; Malik, Omer; Rubenchik, Alexander M.; ...

2017-04-19

Here, the light-matter interaction of an optical beam and metal micro-particulates at the vicinity of an optical substrate surface is critical to the many fields of applied optics. Examples of impacted fields are laser-induced damage in high power laser systems, sub-wavelength laser machining of transmissive materials, and laser-target interaction in directed energy applications. We present a full-wave-based model that predicts the laser-induced plasma pressure exerted on a substrate surface as a result of light absorption in surface-bound micron-scale metal particles. The model predictions agree with experimental observation of laser-induced shallow pits, formed by plasma emission and etching from surface-bound metalmore » micro-particulates. It provides an explanation for the prototypical side lobes observed along the pit profile, as well as for the dependence of the pit shape on the incident laser and particle parameters. Furthermore, the model highlights the significance of the interference of the incident light in the open cavity geometry formed between the micro-particle and the substrate in the resulting pit shape.« less

Interference effects in laser-induced plasma emission from surface-bound metal micro-particles.

PubMed

Feigenbaum, Eyal; Malik, Omer; Rubenchik, Alexander M; Matthews, Manyalibo J

2017-05-01

The light-matter interaction of an optical beam and metal micro-particulates at the vicinity of an optical substrate surface is critical to the many fields of applied optics. Examples of impacted fields are laser-induced damage in high power laser systems, sub-wavelength laser machining of transmissive materials, and laser-target interaction in directed energy applications. We present a full-wave-based model that predicts the laser-induced plasma pressure exerted on a substrate surface as a result of light absorption in surface-bound micron-scale metal particles. The model predictions agree with experimental observation of laser-induced shallow pits, formed by plasma emission and etching from surface-bound metal micro-particulates. It provides an explanation for the prototypical side lobes observed along the pit profile, as well as for the dependence of the pit shape on the incident laser and particle parameters. Furthermore, the model highlights the significance of the interference of the incident light in the open cavity geometry formed between the micro-particle and the substrate in the resulting pit shape.

Acquired pit of the optic nerve: a risk factor for progression of glaucoma.

PubMed

Ugurlu, S; Weitzman, M; Nduaguba, C; Caprioli, J

1998-04-01

To examine acquired pit of the optic nerve as a risk factor for progression of glaucoma. In a retrospective longitudinal study, 25 open-angle glaucoma patients with acquired pit of the optic nerve were compared with a group of 24 open-angle glaucoma patients without acquired pit of the optic nerve. The patients were matched for age, mean intraocular pressure, baseline ratio of neuroretinal rim area to disk area, visual field damage, and duration of follow-up. Serial optic disk photographs and visual fields of both groups were evaluated by three independent observers for glaucomatous progression. Of 46 acquired pits of the optic nerve in 37 eyes of 25 patients, 36 pits were located inferiorly (76%) and 11 superiorly (24%; P < .001). Progression of optic disk damage occurred in 16 patients (64%) in the group with acquired pit and in three patients (12.5%) in the group without acquired pit (P < .001). Progression of visual field loss occurred in 14 patients (56%) in the group with acquired pit and in six (25%) in the group without pit (P=.04). Bilateral acquired pit of the optic nerve was present in 12 patients (48%). Disk hemorrhages were observed more frequently in the group with acquired pit (10 eyes, 40%) compared with the group without pit (two eyes, 8%; P=.02). Among patients with glaucoma, patients with acquired pit of the optic nerve represent a subgroup who are at increased risk for progressive optic disk damage and visual field loss.

Credit PSR. This view depicts the southwest and southeast facades ...

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

Credit PSR. This view depicts the southwest and southeast facades as seen when looking west southwest (260°). The building consists of a small lean-to control room and a two-story space containing a large casting pit. The pit, which can be seen through the open doors, was never used due to changes in JPL's mission. This steel frame structure is clad in "Transite" board (a fire resistant pressed asbestos composite material) and interior lighting consists of individual explosion proof lamps mounted around the walls. The building was rated for 10,000 pounds (4,545 Kg) of class 2 materials and four personnel. It was licensed 5 June 1989 for ammonium perchlorate (NH4C10,), ammonium nitrate (NH4NO3), and sodium nitrate (NaNO3) - Jet Propulsion Laboratory Edwards Facility, Casting & Curing Building, Edwards Air Force Base, Boron, Kern County, CA

43. (Credit JTL) View down into # 3 low service ...

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

43. (Credit JTL) View down into # 3 low service pump pit from elevator car. Worthington low service pump frame on left with pumps at bottom. Tunnel opening leads to #1 low service pump pit. Electric pump housing closest to tunnel opening installed in 1943; pump could deliver 6 mgd. Certrifugal pump near steps was installed in 1947 and is driven by a shaft from a motor at the top of the pit. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

Simplified cost models for prefeasibility mineral evaluations

USGS Publications Warehouse

Camm, Thomas W.

1991-01-01

This report contains 2 open pit models, 6 underground mine models, 11 mill models, and cost equations for access roads, power lines, and tailings ponds. In addition, adjustment factors for variation in haulage distances are provided for open pit models and variation in mining depths for underground models.

Thermal comfort sustained by cold protective clothing in Arctic open-pit mining—a thermal manikin and questionnaire study

PubMed Central

JUSSILA, Kirsi; RISSANEN, Sirkka; AMINOFF, Anna; WAHLSTRÖM, Jens; VAKTSKJOLD, Arild; TALYKOVA, Ljudmila; REMES, Jouko; MÄNTTÄRI, Satu; RINTAMÄKI, Hannu

2017-01-01

Workers in the Arctic open-pit mines are exposed to harsh weather conditions. Employers are required to provide protective clothing for workers. This can be the outer layer, but sometimes also inner or middle layers are provided. This study aimed to determine how Arctic open-pit miners protect themselves against cold and the sufficiency, and the selection criteria of the garments. Workers’ cold experiences and the clothing in four Arctic open-pit mines in Finland, Sweden, Norway and Russia were evaluated by a questionnaire (n=1,323). Basic thermal insulation (Icl) of the reported clothing was estimated (ISO 9920). The Icl of clothing from the mines were also measured by thermal manikin (standing/walking) in 0.3 and 4.0 m/s wind. The questionnaire showed that the Icl of the selected clothing was on average 1.2 and 1.5 clo in mild (−5 to +5°C) and dry cold (−20 to −10°C) conditions, respectively. The Icl of the clothing measured by thermal manikin was 1.9–2.3 clo. The results show that the Arctic open-pit miners’ selected their clothing based on occupational (time outdoors), environmental (temperature, wind, moisture) and individual factors (cold sensitivity, general health). However, the selected clothing was not sufficient to prevent cooling completely at ambient temperatures below −10°C. PMID:29021416

Thermal comfort sustained by cold protective clothing in Arctic open-pit mining-a thermal manikin and questionnaire study.

PubMed

Jussila, Kirsi; Rissanen, Sirkka; Aminoff, Anna; Wahlström, Jens; Vaktskjold, Arild; Talykova, Ljudmila; Remes, Jouko; Mänttäri, Satu; Rintamäki, Hannu

2017-12-07

Workers in the Arctic open-pit mines are exposed to harsh weather conditions. Employers are required to provide protective clothing for workers. This can be the outer layer, but sometimes also inner or middle layers are provided. This study aimed to determine how Arctic open-pit miners protect themselves against cold and the sufficiency, and the selection criteria of the garments. Workers' cold experiences and the clothing in four Arctic open-pit mines in Finland, Sweden, Norway and Russia were evaluated by a questionnaire (n=1,323). Basic thermal insulation (I cl ) of the reported clothing was estimated (ISO 9920). The I cl of clothing from the mines were also measured by thermal manikin (standing/walking) in 0.3 and 4.0 m/s wind. The questionnaire showed that the I cl of the selected clothing was on average 1.2 and 1.5 clo in mild (-5 to +5°C) and dry cold (-20 to -10°C) conditions, respectively. The I cl of the clothing measured by thermal manikin was 1.9-2.3 clo. The results show that the Arctic open-pit miners' selected their clothing based on occupational (time outdoors), environmental (temperature, wind, moisture) and individual factors (cold sensitivity, general health). However, the selected clothing was not sufficient to prevent cooling completely at ambient temperatures below -10°C.

Long-Term Planning for Open Pits for Mining Sulphide-Oxide Ores in Order to Achieve Maximum Profit

NASA Astrophysics Data System (ADS)

Kržanović, Daniel; Conić, Vesna; Stevanović, Dejan; Kolonja, Božo; Vaduvesković, Jovan

2017-12-01

Profitable exploitation of mineralised material from the earth's crust is a complex and difficult task that depends on a comprehensive planning process. Answering the question of how to plan production depends on the geometry of the deposit, as well as the concentration, distribution, and type of minerals in it. The complex nature of mineral deposits largely determines the method of exploitation and profitability of mining operations. In addition to unit operating costs and metal prices, the optimal recovery of and achievement of maximum profit from deposits of sulphide-oxide ores also depend, to a significant extent, on the level of technological recovery achieved in the ore processing procedure. Therefore, in defining a long-term development strategy for open pits, special attention must be paid to the selection of an optimal procedure for ore processing in order to achieve the main objective: maximising the Net Present Value (NPV). The effect of using two different processes, flotation processing and hydrometallurgical methods (bioleaching acid leaching), on determining the ultimate pit is shown in the case of the Kraku Bugaresku-Cementacija sulphide-oxide ore deposit in eastern Serbia. Analysis shows that the application of hydrometallurgical methods of processing sulphide-oxide ore achieved an increase in NPV of 20.42%.

MINE WASTE TECHNOLOGY PROGRAM PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT HIGHWALLS

EPA Science Inventory

This document summarizes the results of Mine Waste Technology Program Activity III, Project 26, Prevention of Acid Mine Drainage Generation from Open-Pit Highwalls. The intent of this project was to obtain performance data on the ability of four technologies to prevent the gener...

Assessing Health Outcomes After Environmental Exposures Associated With Open Pit Burning in Deployed US Service Members.

PubMed

Rohrbeck, Patricia; Hu, Zheng; Mallon, Col Timothy M

2016-08-01

This study assessed the long-term health impact of environmental exposures associated with open pit burning in deployed US service members. Two hundred individuals deployed to Balad, Iraq, and Bagram, Afghanistan, with known exposure to open pits, were matched to 200 non-deployed service members. Both cohorts were observed for adverse health outcomes after returning from deployment. Slight increased risks were observed for respiratory diseases in the Bagram cohort (adj RR: 1.259), and for cardiovascular disease in the Balad cohort (adj RR: 1.072), but the findings were not significant. The combined deployed cohort showed lower risks for adverse health outcomes, suggesting a healthy deployer effect. In conclusion, this study did not find significantly increased risks for selected health outcomes after burn pit exposure during deployment among two deployed cohorts compared with a non-deployed cohort.

13. DETAIL WEST OF TURBINE PIT SHOWING PIT DRAINED AND ...

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

13. DETAIL WEST OF TURBINE PIT SHOWING PIT DRAINED AND TURBINE EXPOSED. ORIGINAL WATER LEVEL SHOWN BY LINE JUST ABOVE ARCHED OPENING TO LEFT. WATER LINE AFTER 1982 INSTALLATION OF FLASH BOARDS REVEALED BY DARK STAIN. - Middle Creek Hydroelectric Dam, On Middle Creek, West of U.S. Route 15, 3 miles South of Selinsgrove, Selinsgrove, Snyder County, PA

Quantification of skeletal fraction volume of a soil pit by means of photogrammetry

NASA Astrophysics Data System (ADS)

Baruck, Jasmin; Zieher, Thomas; Bremer, Magnus; Rutzinger, Martin; Geitner, Clemens

2015-04-01

The grain size distribution of a soil is a key parameter determining soil water behaviour, soil fertility and land use potential. It plays an important role in soil classification and allows drawing conclusions on landscape development as well as soil formation processes. However, fine soil material (i.e. particle diameter ≤2 mm) is usually documented more thoroughly than the skeletal fraction (i.e. particle diameter >2 mm). While fine soil material is commonly analysed in the laboratory in order to determine the soil type, the skeletal fraction is typically estimated in the field at the profile. For a more precise determination of the skeletal fraction other methods can be applied and combined. These methods can be volume-related (sampling rings, percussion coring tubes) or non-volume-related (sieve of spade excavation). In this study we present a framework for the quantification of skeletal fraction volumes of a soil pit by means of photogrammetry. As a first step 3D point clouds of both soil pit and skeletal grains were generated. Therefore all skeletal grains of the pit were spread out onto a plane, clean plastic sheet in the field and numerous digital photos were taken using a reflex camera. With the help of the open source tool VisualSFM (structure from motion) two scaled 3D point clouds were derived. As a second step the skeletal fraction point cloud was segmented by radiometric attributes in order to determine volumes of single skeletal grains. The comparison of the total skeletal fraction volume with the volume of the pit (closed by spline interpolation) yields an estimate of the volumetric proportion of skeletal grains. The presented framework therefore provides an objective reference value of skeletal fraction for the support of qualitative field records.

A New Methodology for Open Pit Slope Design in Karst-Prone Ground Conditions Based on Integrated Stochastic-Limit Equilibrium Analysis

NASA Astrophysics Data System (ADS)

Zhang, Ke; Cao, Ping; Ma, Guowei; Fan, Wenchen; Meng, Jingjing; Li, Kaihui

2016-07-01

Using the Chengmenshan Copper Mine as a case study, a new methodology for open pit slope design in karst-prone ground conditions is presented based on integrated stochastic-limit equilibrium analysis. The numerical modeling and optimization design procedure contain a collection of drill core data, karst cave stochastic model generation, SLIDE simulation and bisection method optimization. Borehole investigations are performed, and the statistical result shows that the length of the karst cave fits a negative exponential distribution model, but the length of carbonatite does not exactly follow any standard distribution. The inverse transform method and acceptance-rejection method are used to reproduce the length of the karst cave and carbonatite, respectively. A code for karst cave stochastic model generation, named KCSMG, is developed. The stability of the rock slope with the karst cave stochastic model is analyzed by combining the KCSMG code and the SLIDE program. This approach is then applied to study the effect of the karst cave on the stability of the open pit slope, and a procedure to optimize the open pit slope angle is presented.

Newly reported lupus and rheumatoid arthritis in relation to deployment within proximity to a documented open-air burn pit in Iraq.

PubMed

Jones, Kelly A; Smith, Besa; Granado, Nisara S; Boyko, Edward J; Gackstetter, Gary D; Ryan, Margaret A K; Phillips, Christopher J; Smith, Tyler C

2012-06-01

To assess the relationship between possible exposure to smoke from documented open-air burn pits and newly reported lupus and rheumatoid arthritis among Millennium Cohort participants who have deployed in support of operations in Iraq and Afghanistan. Prospectively assessed self-reported lupus and rheumatoid arthritis among deployers who completed both 2004-2006 and 2007-2008 questionnaires. After exclusions, more than 18,000 participants were deployed, including more than 3000 participants deployed within a 3-mile radius of a documented burn pit. After adjustment, proximity within 3 miles of a burn pit was not significantly associated with rheumatoid arthritis or lupus in general; however, one location was associated with lupus, although few cases were at this site (n = 2). Results indicate deployers potentially exposed to documented burn pits in the combined three-camp analysis were not at an elevated risk of lupus or rheumatoid arthritis.

The effects of exposure to documented open-air burn pits on respiratory health among deployers of the Millennium Cohort Study.

PubMed

Smith, Besa; Wong, Charlene A; Boyko, Edward J; Phillips, Christopher J; Gackstetter, Gary D; Ryan, Margaret A K; Smith, Tyler C

2012-06-01

To investigate respiratory illnesses and potential open-air burn pit exposure among Millennium Cohort participants who deployed to Iraq or Afghanistan. Using multivariable logistic regression, newly reported chronic bronchitis or emphysema, newly reported asthma, and self-reported respiratory symptoms and possible burn pit exposure within 2, 3, or 5 miles were examined among Army and Air Force deployers surveyed in 2004 to 2006 and 2007 to 2008 (n = 22,844). Burn pit exposure within 3 or 5 miles was not associated with respiratory outcomes after statistical adjustment. Increased symptom reporting was observed among Air Force deployers located within 2 miles of Joint Base Balad; however, this finding was marginally significant with no evidence of trend. In general, these findings do not support an elevated risk for respiratory outcomes among personnel deployed within proximity of documented burn pits in Iraq.

Prospective assessment of chronic multisymptom illness reporting possibly associated with open-air burn pit smoke exposure in Iraq.

PubMed

Powell, Teresa M; Smith, Tyler C; Jacobson, Isabel G; Boyko, Edward J; Hooper, Tomoko I; Gackstetter, Gary D; Phillips, Christopher J; Smith, Besa

2012-06-01

To investigate the relationship between chronic multisymptom illness (CMI) and possible exposure to an open-air burn pit at three selected bases among those deployed to operations in Iraq and Afghanistan. Chronic multisymptom illness (reporting at least one symptom in at least two of the following symptom constructs: general fatigue; mood and cognition problems; and musculoskeletal discomfort) was assessed, differentiating by potential burn pit exposure, among deployers who completed 2004 and 2007 Millennium Cohort questionnaires. More than 21,000 Cohort participants were deployed in support of the current operations, including more than 3000 participants with at least one deployment within a 3-mile radius of a documented burn pit. After adjusting for covariates, no elevated risk of CMI was observed among those exposed. There was no increase in CMI symptom reporting in those deployed to three selected bases with documented burn pits compared with other deployers.

A Method of Effective Quarry Water Purifying Using Artificial Filtering Arrays

NASA Astrophysics Data System (ADS)

Tyulenev, M.; Garina, E.; Khoreshok, A.; Litvin, O.; Litvin, Y.; Maliukhina, E.

2017-01-01

The development of open pit mining in the large coal basins of Russia and other countries increases their negative impact on the environment. Along with the damage of land and air pollution by dust and combustion gases of blasting, coal pits have a significant negative impact on water resources. Polluted quarry water worsens the ecological situation on a much larger area than covered by air pollution and land damage. This significantly worsens the conditions of people living in cities and towns located near the coal pits, and complicates the subsequent restoration of the environment, irreversibly destroying the nature. Therefore, the research of quarry wastewater purifying is becoming an important mater for scholars of technical colleges and universities in the regions with developing open-pit mining. This paper describes the method of determining the basic parameters of the artificial filtering arrays formed on coal pits of Kuzbass (Western Siberia, Russia), and gives recommendations on its application.

Comet 67P's Pitted Surface

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2015-11-01

High-resolution imagery of comet 67P ChuryumovGerasimenko has revealed that its surface is covered in active pits some measuring hundreds of meters both wide and deep! But what processes caused these pits to form?Pitted LandscapeESAs Rosetta mission arrived at comet 67P in August 2014. As the comet continued its journey around the Sun, Rosetta extensively documented 67Ps surface through high-resolution images taken with the on-board instrument NavCam. These images have revealed that active, circular depressions are a common feature on the comets surface.In an attempt to determine how these pits formed, an international team of scientists led by Olivier Mousis (Laboratory of Astrophysics of Marseille) has run a series of simulations of a region of the comet the Seth region that contains a 200-meter-deep pit. These simulations include the effects of various phase transitions, heat transfer through the matrix of ices and dust, and gas diffusion throughout the porous material.Escaping VolatilesAdditional examples of pitted areas on 67Ps northern-hemisphere surface include the Ash region and the Maat region (both imaged September 2014 by NavCam) [Mousis et al. 2015]Previous studies have already eliminated two potential formation mechanisms for the pits: impacts (the sizes of the pits werent right) and erosion due to sunlight (the pits dont have the right shape). Mousis and collaborators assume that the pits are instead caused by the depletion of volatile materials chemical compounds with low boiling points either via explosive outbursts at the comets surface, or via sinkholes opening from below the surface. But what process causes the volatiles to deplete when the comet heats?The authors simulations demonstrate that volatiles trapped beneath the comets surface either in icy structures called clathrates or within amorphous ice can be suddenly released as the comet warms up. The team shows that the release of volatiles from these two structures can create 200-meter-deep pits within ~800 years and ~2,000 years, respectively. Since comet 67P has been around the inner solar system for about 7,000 years, both of these processes are viable explanations for the pits.The simulations also show that direct sublimation of crystalline ices of water, carbon monoxide, and carbon dioxide can cause deep pits but only in the absence of a surface layer of dust, known as a dust mantle, in that region of the comet. Direct sublimation could be a viable explanation for the pits, then, if dust grains in the area are so small that they are carried away with the released gas, rather than falling back to form a layer on the comets surface.Regardless of the formation mechanism for these pits, the authors conclude that their very existence implies that the physical and chemical properties across the surface and subsurface of the comet cannot be uniform. Further observations from Rosetta will continue to help us understand comet 67P.CitationO. Mousis et al 2015 ApJ 814 L5. doi:10.1088/2041-8205/814/1/L5

77 FR 22609 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Pan Mine Project...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-16

... business hours. SUPPLEMENTARY INFORMATION: Midway Gold US Inc. (Midway) proposes to construct and operate an open-pit gold mining operation, which would include open pits, a heap leach pad, waste rock dumps, and ancillary facilities. The mine would be located in the northern part of the Pancake Mountain Range...

Haulage Truck Operator. Open Pit Mining Job Training Series.

ERIC Educational Resources Information Center

British Columbia Dept. of Education, Victoria.

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

Rotary Drill Operator. Open Pit Mining Job Training Series.

ERIC Educational Resources Information Center

Savilow, Bill

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

Track Dozer Operator. Open Pit Mining Job Training Series.

ERIC Educational Resources Information Center

British Columbia Dept. of Education, Victoria.

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

Grader Operator. Open Pit Mining Job Training Series.

ERIC Educational Resources Information Center

Savilow, Bill

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

Heavy Duty Tireman. Open Pit Mining Job Training Series.

ERIC Educational Resources Information Center

McColman, Don

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

Rubber Tire Dozer Operator. Open Pit Mining Job Training Series.

ERIC Educational Resources Information Center

British Columbia Dept. of Education, Victoria.

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

Front End Loader Operator. Open Pit Mining Job Training Series.

ERIC Educational Resources Information Center

Savilow, Bill

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

Shovel Operator. Open Pit Mining Job Training Series.

ERIC Educational Resources Information Center

Hartley, Larry

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

Developing an Ecological Passport for an Open-Pit Dump Truck to Reduce Negative Effect on Environment

NASA Astrophysics Data System (ADS)

Koptev, V. Yu; Kopteva, A. V.

2017-05-01

Expanding the open-pit dump truck usage areas and the need to transport more and more minerals results in producing more and more powerful open-pit dump trucks, and this all is about environmental problems and potential health risks for the personnel. Harmful gas concentrations in working areas became threatening enough to have the work in some areas completely halted, until the contents of harmful substances in the air, as well as visibility on the roads, get back to norm. The article represents the new methodology for assessing comparatively the efficiency of modern transportation systems with performance and ecology characteristics taken into account, by developing an ecological passport for machines, facilitating design improvements and reducing pollution during operation.

Selenium bioaccumulation in stocked fish as an indicator of fishery potential in pit lakes on reclaimed coal mines in Alberta, Canada.

PubMed

Miller, L L; Rasmussen, J B; Palace, V P; Sterling, G; Hontela, A

2013-07-01

Pit lakes are a common reclamation strategy for open pit mines; however, there is a concern about their water quality and suitability as fish habitat because they are often contaminated by metals or metalloids. This study assessed the exposure of fish and invertebrates to selenium (Se) and other metals and metalloids in pit lakes formed by open pit coal mining in Tertiary (thermal coal) and in Cretaceous (metallurgical coal) bedrock. Juvenile hatchery rainbow trout, Oncorhynchus mykiss, and brook trout, Salvelinus fontinalis, were stocked into two thermal coal pit lakes (water Se < 2 μg/L, low water Se) and two metallurgical coal pit lakes (water Se > 15 μg/L, high water Se). Se accumulation in stocked fish and concentrations in invertebrates were characterized over a period of 2 years. In the metallurgical pits, invertebrates had higher Se concentrations and fish accumulated Se to higher levels (exceeding USEPA tissue Se guidelines) than biota in the thermal pits. Rainbow and brook trout accumulated similar concentrations of Se in their muscle and exhibited a similar relationship between whole-body and muscle Se concentrations. These results may be used by resource managers to assess compliance with whole-body tissue Se guidelines and to determine if pit lakes in coal mining areas pose a significant Se risk to wildlife or human health. The high Se exposure in metallurgical coal pits indicates that under the current mining and reclamation strategy, these lakes are not suitable for management as recreational "put and take" fisheries.

A novel environmental restoration method for an abandoned limestone quarry with a deep open pit and steep palisades: a case study

PubMed Central

Wang, Hanxun; Bai, Xueliang; Shi, Lei

2018-01-01

In general, exploitation of rock materials, such as limestone or granite exploitation, can cause serious damage to the environment near a mine area. With economic development and the ever-increasing demand for ore resources, mining activities have induced very serious environmental issues in China. Therefore, environmental restoration work around mines in China is urgently required. This study explores the Chuankou open-pit limestone quarry in Tongchuan City, Shaanxi Province, Northwest China, as the engineering case. The environmental issues caused by over 40 years of limestone exploitation, including land degradation, land occupation, dust pollution and potential geological disasters, were investigated. Combining the characteristics of this quarry with a summary of previous studies on environmental restoration work, this paper proposes a novel and systematic method that was comprehensively carried out through engineering and revegetation measures. The engineering measure, that is, the construction of an artificial slope by using local abandoned construction materials, solved the environmental problems in this quarry and provided site conditions favourable for revegetation. The revegetation measure restored the local ecosystem. This method provides both a new idea for the sustainable development of a mining area and a useful reference for analogous engineering cases. PMID:29892461

Pitted terrains on (1) Ceres and implications for shallow subsurface volatile distribution

PubMed Central

Platz, T.; Schorghofer, N.; Prettyman, T. H.; De Sanctis, M. C.; Crown, D. A.; Schmedemann, N.; Neesemann, A.; Kneissl, T.; Marchi, S.; Schenk, P. M.; Bland, M. T.; Schmidt, B. E.; Hughson, K. H. G.; Tosi, F.; Zambon, F.; Mest, S. C.; Yingst, R. A.; Williams, D. A.; Russell, C. T.; Raymond, C. A.

2017-01-01

Abstract Prior to the arrival of the Dawn spacecraft at Ceres, the dwarf planet was anticipated to be ice‐rich. Searches for morphological features related to ice have been ongoing during Dawn's mission at Ceres. Here we report the identification of pitted terrains associated with fresh Cerean impact craters. The Cerean pitted terrains exhibit strong morphological similarities to pitted materials previously identified on Mars (where ice is implicated in pit development) and Vesta (where the presence of ice is debated). We employ numerical models to investigate the formation of pitted materials on Ceres and discuss the relative importance of water ice and other volatiles in pit development there. We conclude that water ice likely plays an important role in pit development on Ceres. Similar pitted terrains may be common in the asteroid belt and may be of interest to future missions motivated by both astrobiology and in situ resource utilization. PMID:28989206

Pitted terrains on (1) Ceres and implications for shallow subsurface volatile distribution.

PubMed

Sizemore, H G; Platz, T; Schorghofer, N; Prettyman, T H; De Sanctis, M C; Crown, D A; Schmedemann, N; Neesemann, A; Kneissl, T; Marchi, S; Schenk, P M; Bland, M T; Schmidt, B E; Hughson, K H G; Tosi, F; Zambon, F; Mest, S C; Yingst, R A; Williams, D A; Russell, C T; Raymond, C A

2017-07-16

Prior to the arrival of the Dawn spacecraft at Ceres, the dwarf planet was anticipated to be ice-rich. Searches for morphological features related to ice have been ongoing during Dawn's mission at Ceres. Here we report the identification of pitted terrains associated with fresh Cerean impact craters. The Cerean pitted terrains exhibit strong morphological similarities to pitted materials previously identified on Mars (where ice is implicated in pit development) and Vesta (where the presence of ice is debated). We employ numerical models to investigate the formation of pitted materials on Ceres and discuss the relative importance of water ice and other volatiles in pit development there. We conclude that water ice likely plays an important role in pit development on Ceres. Similar pitted terrains may be common in the asteroid belt and may be of interest to future missions motivated by both astrobiology and in situ resource utilization.

Pitted terrains on (1) Ceres and implications for shallow subsurface volatile distribution

USGS Publications Warehouse

Sizemore, H.G.; Platz, Thomas; Schorghofer, Norbert; Prettyman, Thomas; De Sanctis, Maria Christina; Crown, David A.; Schmedemann, Nico; Nessemann, Andeas; Kneissl, Thomas; Simone Marchi,; Schenk, Paul M.; Bland, Michael T.; Schmidt, B.E.; Hughson, Kynan H.G.; Tosi, F.; Zambon, F; Mest, S.C.; Yingst, R.A.; Williams, D.A.; Russell, C.T.; Raymond, C.A.

2017-01-01

Prior to the arrival of the Dawn spacecraft at Ceres, the dwarf planet was anticipated to be ice-rich. Searches for morphological features related to ice have been ongoing during Dawn's mission at Ceres. Here we report the identification of pitted terrains associated with fresh Cerean impact craters. The Cerean pitted terrains exhibit strong morphological similarities to pitted materials previously identified on Mars (where ice is implicated in pit development) and Vesta (where the presence of ice is debated). We employ numerical models to investigate the formation of pitted materials on Ceres and discuss the relative importance of water ice and other volatiles in pit development there. We conclude that water ice likely plays an important role in pit development on Ceres. Similar pitted terrains may be common in the asteroid belt and may be of interest to future missions motivated by both astrobiology and in situ resource utilization.

Pit membranes of Ephedra resemble gymnosperms more than angiosperms

Treesearch

Roland Dute; Lauren Bowen; Sarah Schier; Alexa Vevon; Troy Best; Maria Auad; Thomas Elder; Pauline Bouche; Steven Jansen

2014-01-01

Bordered pit pairs of Ephedra species were characterized using different types of microscopy. Pit membranes contained tori that did not stain for lignin. SEM and AFM views of the torus surface showed no plasmodesmatal openings, but branched, secondary plasmodesmata were occasionally noted using TEM in conjunction with ultrathin sections. The margo consisted of radial...

Modeling the Use of Mine Waste Rock as a Porous Medium Reservoir for Compressed Air Energy Storage

NASA Astrophysics Data System (ADS)

Donelick, R. A.; Donelick, M. B.

2016-12-01

We are studying the engineering and economic feasibilities of constructing Big Mass Battery (BiMBy) compressed air energy storage devices using some of the giga-tonnes of annually generated and historically produced mine waste rock/overburden/tailings (waste rock). This beneficial use of waste rock is based on the large mass (Big Mass), large pore volume, and wide range of waste rock permeabilities available at some large open pit metal mines and coal strip mines. Porous Big Mass is encapsulated and overlain by additional Big Mass; compressed air is pumped into the encapsulated pore space when renewable energy is abundant; compressed air is released from the encapsulated pore space to run turbines to generate electricity at the grid scale when consumers demand electricity. Energy storage capacity modeling: 1) Yerington Pit, Anaconda Copper Mine, Yerington, NV (inactive metal mine): 340 Mt Big Mass, energy storage capacity equivalent to 390k-710k home batteries of size 10 kW•h/charge, assumed 20% porosity, 50% overall efficiency. 2) Berkeley Pit, Butte Copper Mine, Butte, MT (inactive metal mine): 870 Mt Big Mass, energy storage capacity equivalent to 1.4M-2.9M home batteries of size 10 kW•h/charge, assumed 20% porosity, 50% overall efficiency. 3) Rosebud Mine, Colstrip, MT (active coal strip mine): 87 Mt over 2 years, energy storage capacity equivalent to 45k-67k home batteries of size 10 kW•h/charge, assumed 30% porosity, 50% overall efficiency. Encapsulating impermeable layer modeling: Inactive mine pits like Yerington Pit and Berkeley Pit, and similar active pits, have associated with them low permeability earthen material (silt and clay in Big Mass) at sufficient quantities to manufacture an encapsulating structure with minimal loss of efficiency due to leakage, a lifetime of decades or even centuries, and minimal need for the use of geomembranes. Active coal strip mines like Rosebud mine have associated with them low permeability earthen material such as coal combustion products (fly ash, bottom ash, boiler slag, other) that may be put to beneficial use as part of the encapsulating structure; however, coal strip mines have lower volume to surface ratios than mine pits increasing the potential need to use geomembranes.

Oceanic corrosion test of bare and zinc-protected aluminum alloys for seawater heat exchangers

NASA Technical Reports Server (NTRS)

Sasscer, D. S.; Morgan, T. O.; Rivera, C.; Ernst, R.; Scott, A. C.; Summerson, T. J.

1982-01-01

Bare 3004 tubes, 7072 Alclad 3004 tubes, and bare and zinc diffusion treated 3003 extrusions from a brazed aluminum, plate-fin heat exchanger were exposed to 1.8 m/sec flowing seawater aboard an open ocean test facility moored 3.4 km off the southeast coast of Puerto Rico. After six months exposure, the average corrosion rates for most varieties of aluminum materials converged to a low value of 0.015 mm/yr (0.6 mils/yr). Pitting did not occur in bare 3003 and 3004 samples during the six month test. Pitting did occur to varying degrees in the Alclad and zinc diffusion treated material, but did not penetrate to the base metal. Biofouling countermeasures (intermittent chlorination and brushing) did not affect the corrosion rates to any significant extent. Intermittent chlorination at a level of 0.5 ppm for 28 minutes daily controlled microbiofouling of the samples but did not prevent the development of a macrobiofouling community in areas of the plumbing with low flow.

A decision support system using analytical hierarchy process (AHP) for the optimal environmental reclamation of an open-pit mine

NASA Astrophysics Data System (ADS)

Bascetin, A.

2007-04-01

The selection of an optimal reclamation method is one of the most important factors in open-pit design and production planning. It also affects economic considerations in open-pit design as a function of plan location and depth. Furthermore, the selection is a complex multi-person, multi-criteria decision problem. The group decision-making process can be improved by applying a systematic and logical approach to assess the priorities based on the inputs of several specialists from different functional areas within the mine company. The analytical hierarchy process (AHP) can be very useful in involving several decision makers with different conflicting objectives to arrive at a consensus decision. In this paper, the selection of an optimal reclamation method using an AHP-based model was evaluated for coal production in an open-pit coal mine located at Seyitomer region in Turkey. The use of the proposed model indicates that it can be applied to improve the group decision making in selecting a reclamation method that satisfies optimal specifications. Also, it is found that the decision process is systematic and using the proposed model can reduce the time taken to select a optimal method.

Ensuring the Environmental and Industrial Safety in Solid Mineral Deposit Surface Mining

NASA Astrophysics Data System (ADS)

Trubetskoy, Kliment; Rylnikova, Marina; Esina, Ekaterina

2017-11-01

The growing environmental pressure of mineral deposit surface mining and severization of industrial safety requirements dictate the necessity of refining the regulatory framework governing safe and efficient development of underground resources. The applicable regulatory documentation governing the procedure of ore open-pit wall and bench stability design for the stage of pit reaching its final boundary was issued several decades ago. Over recent decades, mining and geomechanical conditions have changed significantly in surface mining operations, numerous new software packages and computer developments have appeared, opportunities of experimental methods of source data collection and processing, grounding of the permissible parameters of open pit walls have changed dramatically, and, thus, methods of risk assessment have been perfected [10-13]. IPKON RAS, with the support of the Federal Service for Environmental Supervision, assumed the role of the initiator of the project for the development of Federal norms and regulations of industrial safety "Rules for ensuring the stability of walls and benches of open pits, open-cast mines and spoil banks", which contribute to the improvement of economic efficiency and safety of mineral deposit surface mining and enhancement of the competitiveness of Russian mines at the international level that is very important in the current situation.

3D Modeling of Landslide in Open-pit Mining on Basis of Ground-based LIDAR Data

NASA Astrophysics Data System (ADS)

Hu, H.; Fernandez-Steeger, T. M.; Azzam, R.; Arnhardt, C.

2009-04-01

Slope stability is not only an important problem which is related to production and safety in open-pit mining, but also very complex task. There are three main reasons which affect the slope stability as follows: geotechnical factors: Geological structure, lithologic characteristics, water, cohesion, friction, etc.; climate factors: Rainfall and temperature; and external factors: Open-pit mining process, explosion vibration, dynamic load, etc.. The 3rd reason, as a specially one in open-pit mining, not only causes some dynamic problems but also induces the fast geometry changing which must be considered in the following research using numerical simulation and stability analysis. Recently, LIDAR technology has been applied in many fields and places in the world wide. Ground-based LIDAR technology with high accuracy up to 3mm increasingly accommodates to monitoring landslides and detecting changing. LIDAR data collection and preprocessing research have been carried out by Department of Engineering Geology and Hydrogeology at RWTH Aachen University. LIDAR data, so-called a point-cloud of mass data in high density can be obtained in short time for the sensitive open-pit mining area by using ground-based LIDAR. To obtain a consistent surface model, it is necessary to set up multiple scans with the ground-based LIDAR. The framework of data preprocessing which can be implemented by Poly-Works is introduced as follows: gross error detection and elimination, integration of reference frame, model fusion of different scans (re-sampled in overlap region), data reduction without removing the useful information which is a challenge and research front in LIDAR data processing. After data preprocessing, 3D surface model can be directly generated in Poly-Works or generated in other software by building the triangular meshes. The 3D surface landslide model can be applied to further researches such as: real time landslide geometry monitoring due to the fast data collection and processing; change detecting by means of overlying different periods of topographic or geometric data; FEM (Finite Element Method) numerical simulation on basis of combining with the geotechnical properties and parameters to analyze slope stability and predict future movements for designing and rectifying the open-pit mining process; using the reverse engineering thought for developing constitutive models. An improved 3D surface model (HRDEM) which is based on fast data collection and precise data processing on basis of ground-based LIDAR technology is important contribution for further researches of slope stability in open-pit mining area.

Use of Electrochemical Noise (EN) Technique to Study the Effect of sulfate and Chloride Ions on Passivation and Pitting Corrosion Behavior of 316 Stainless Steel

NASA Astrophysics Data System (ADS)

Pujar, M. G.; Anita, T.; Shaikh, H.; Dayal, R. K.; Khatak, H. S.

2007-08-01

In the present paper, studies were conducted on AISI Type 316 stainless steel (SS) in deaerated solutions of sodium sulfate as well as sodium chloride to establish the effect of sulfate and chloride ions on the electrochemical corrosion behavior of the material. The experiments were conducted in deaerated solutions of 0.5 M sodium sulfate as well as 0.5 M sodium chloride using electrochemical noise (EN) technique at open circuit potential (OCP) to collect the correlated current and potential signals. Visual records of the current and potential, analysis of data to arrive at the statistical parameters, spectral density estimation using the maximum entropy method (MEM) showed that sulfate ions were incorporated in the passive film to strengthen the same. However, the adsorption of chloride ions resulted in pitting corrosion thereby adversely affecting noise resistance ( R N). Distinct current and potential signals were observed for metastable pitting, stable pitting and passive film build-up. Distinct changes in the values of the statistical parameters like R N and the spectral noise resistance at zero frequency ( R°SN) revealed adsorption and incorporation of sulfate and chloride ions on the passive film/solution interface.

Primitive environment control for preservation of pit relics in archeology museums of China.

PubMed

Gu, Zhaolin; Luo, Xilian; Meng, Xiangzhao; Wang, Zanshe; Ma, Tao; Yu, Chuck; Rong, Bo; Li, Ku; Li, Wenwu; Tan, Ying

2013-02-05

Immovable historical relics in some archeology museums of China suffer deterioration due to their improper preservation environment. The existing environmental control systems used in archeology museums are often designed for the amenities of visitors, and these manipulated environments are often inappropriate for the conservation of abiotic relics. This paper points out that the large open space of the existing archeology museum could be a cause of deterioration of the relics from the point of view of indoor air convective flow. The paper illustrates the need to introduce a local pit environmental control, which could reintegrate a pit primitive environment for the preservation of the historical relics by using an air curtain system, orientated to isolate the unearthed relics, semiexposed in pits to the large gallery open space of the exhibition hall.

A Comprehensive Pitting Study of High Velocity Oxygen Fuel Inconel 625 Coating by Using Electrochemical Testing Techniques

NASA Astrophysics Data System (ADS)

Niaz, Akbar; Khan, Sajid Ullah

2016-01-01

In the present work, Inconel 625 was coated on a mild steel substrate using a high velocity oxygen fuel coating process. The pitting propensity of the coating was tested by using open circuit potential versus time, potentiodynamic polarization, electrochemical potentiokinetic reactivation, and scanning electrochemical microscopy. The pitting propensity of the coating was compared with bulk Inconel 625 alloy. The results confirmed that there were regions of different electrochemical activities on the coating which have caused pitting corrosion.

Quantification of proportions of different water sources in a mining operation.

PubMed

Scheiber, Laura; Ayora, Carlos; Vázquez-Suñé, Enric

2018-04-01

The water drained in mining operations (galleries, shafts, open pits) usually comes from different sources. Evaluating the contribution of these sources is very often necessary for water management. To determine mixing ratios, a conventional mass balance is often used. However, the presence of more than two sources creates uncertainties in mass balance applications. Moreover, the composition of the end-members is not commonly known with certainty and/or can vary in space and time. In this paper, we propose a powerful tool for solving such problems and managing groundwater in mining sites based on multivariate statistical analysis. This approach was applied to the Cobre Las Cruces mining complex, the largest copper mine in Europe. There, the open pit water is a mixture of three end-members: runoff (RO), basal Miocene (Mb) and Paleozoic (PZ) groundwater. The volume of water drained from the Miocene base aquifer must be determined and compensated via artificial recharging to comply with current regulations. Through multivariate statistical analysis of samples from a regional field campaign, the compositions of PZ and Mb end-members were firstly estimated, and then used for mixing calculations at the open pit scale. The runoff end-member was directly determined from samples collected in interception trenches inside the open pit. The application of multivariate statistical methods allowed the estimation of mixing ratios for the hydrological years 2014-2015 and 2015-2016. Open pit water proportions have changed from 15% to 7%, 41% to 36%, and 44% to 57% for runoff, Mb and PZ end-members, respectively. An independent estimation of runoff based on the curve method yielded comparable results. Copyright © 2017 Elsevier B.V. All rights reserved.

Rain Erosion Studies of Sapphire, Aluminum Oxynitride, Spinel, Lanthana- Doped Yttria, and TAF Glass

DTIC Science & Technology

1990-07-01

small , there is little change in average scatter for any material in any test. CONCLUSIONS AND DISCUSSION The principal conclusions are 1. ALON...20 Sample broke erosion damage 10 Slight pitting, 20 No change erosion damage 15 Pitting, cratering, 20 Small surface pits erosion damage 15 Pitting...Sample broke 10 No damage 15 Sample pitted, small edge fracture 15 Slight pitting, 1 crater, 20 Sample pitted, erosion damage small edge fracture 15 SUght

Developing Mathematical Provisions for Assessment of Liquid Hydrocarbon Emissions in Emergency Situations

NASA Astrophysics Data System (ADS)

Zemenkova, M. Yu; Zemenkov, Yu D.; Shantarin, V. D.

2016-10-01

The paper reviews the development of methodology for calculation of hydrocarbon emissions during seepage and evaporation to monitor the reliability and safety of hydrocarbon storage and transportation. The authors have analyzed existing methods, models and techniques for assessing the amount of evaporated oil. Models used for predicting the material balance of multicomponent two-phase systems have been discussed. The results of modeling the open-air hydrocarbon evaporation from an oil spill are provided and exemplified by an emergency pit. Dependences and systems of differential equations have been obtained to assess parameters of mass transfer from the open surface of a liquid multicomponent mixture.

Proceedings of GeoTech 85: Personal computers in geology conference

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

Not Available

1985-01-01

This book presents the papers given at a conference which considered the use of microprocessors in the exploration of petroleum and natural gas deposits. Topics covered at the conference included seismic surveys, geochemistry, expert systems, artificial intelligence, data base management systems, a portable exploration work station, open pit planning on a microcomputer, well logging, fracture analysis, production scheduling of open pit mines, resistivity logging, and coal washability.

Evaluation of groundwater pollution in a mining area using analytical solution: a case study of the Yimin open-pit mine in China.

PubMed

Li, Tianxin; Li, Li; Song, Hongqing; Meng, Linglong; Zhang, Shuli; Huang, Gang

2016-01-01

This study focused on using analytical and numerical models to develop and manage groundwater resources, and predict the effects of management measurements in the groundwater system. Movement of contaminants can be studied based on groundwater flow characteristics. This study can be used for prediction of ion concentration and evaluation of groundwater pollution as the theoretical basis. The Yimin open-pit mine is located in the northern part of the Inner Mongolia Autonomous Region of China. High concentrations of iron and manganese are observed in Yimin open-pit mine because of exploitation and pumping that have increased the concentration of the ions in groundwater. In this study, iron was considered as an index of contamination, and the solute model was calibrated using concentration observations from 14 wells in 2014. The groundwater flow model and analytical solutions were used in this study to forecast pollution concentration and variation trend after calibration. With continuous pumping, contaminants will migrate, and become enriched, towards the wellhead in the flow direction. The concentration of the contaminants and the range of pollution increase with the flow rate increased. The suitable flow rate of single well should be <380 m/day at Yimin open-pit for the standard value of pollution concentration.

Uranium activity ratio in water and fish from pit lakes in Kurday, Kazakhstan and Taboshar, Tajikistan.

PubMed

Strømman, G; Rosseland, B O; Skipperud, L; Burkitbaev, L M; Uralbekov, B; Heier, L S; Salbu, B

2013-09-01

Kurday in Kazhakstan and Taboshar in Tajikistan were U mining sites operated during the 1950s and 1960s as part of the USSR nuclear weapon program. Today, they represent sources of potential U contamination of the environment. Within both mining sites, open pits from which U ore was extracted have been filled with water due to ground water inflow and precipitation. These artificial pit lakes contain fish consumed occasionally by the local people, and wild and domestic animals are using the water for drinking purposes. To assess the potential impact from U in these pit lakes, field work was performed in 2006 in Kurday and 2006 and 2008 in Taboshar. Results show that the U concentration in the lake waters were relatively high, about 1 mg/L in Kurday Pit Lake and about 3 mg/L in Taboshar Pit Lake. The influence of U-bearing materials on the lakes and downstream waters were investigated by measuring the U concentration and the (234)U/(238)U activity ratios. In both Kurday and Taboshar, the ratios increased distinctively from about 1 at the pit lakes to >1.5 far downstream the lakes. The concentrations of (238)U in gill, liver, muscle and bones in fish from the pit lakes were much higher than in the reference fish. Peak concentration of U was seen in bones (13 mg/kg w.w.), kidney (9.1 mg/kg w.w.) and gills (8.9 mg/kg w.w.) from Cyprinus auratus caught in the Taboshar Pit Lake. Bioconcentration factors (BCF) calculated for organs from fish caught in the Taboshar Pit Lake, with the same tendency seen in the Kurday Pit Lake, showed that U accumulates most in bone (BCF = 4.8 L/kg w.w.), gills (BCF = 3.6 L/kg w.w.), kidney (BCF = 3.6 L/kg w.w.), and liver (BCF = 2.5 L/kg w.w.), while least was accumulated in the muscle (BCF = 0.12 L/kg w.w.). Copyright © 2012 Elsevier Ltd. All rights reserved.

Geological and technological evaluation of gold-bearing mineral material after photo-electrochemical activation leaching

NASA Astrophysics Data System (ADS)

Manzyrev, DV

2017-02-01

The paper reports the lab test results on simulation of heap leaching of unoxidized rebellious ore extracted from deep levels of Pogromnoe open pit mine, with different flowsheets and photo-electrochemically activated solutions. It has been found that pre-treatment of rebellious ore particles -10 mm in size by photo-electrochemically activated solutions at the stage preceding agglomeration with the use of rich cyanide solutions enhances gold recovery by 6%.

Copper Tube Pitting in Santa Fe Municipal Water Caused by Microbial Induced Corrosion.

PubMed

Burleigh, Thomas D; Gierke, Casey G; Fredj, Narjes; Boston, Penelope J

2014-06-05

Many copper water lines for municipal drinking water in Santa Fe, New Mexico USA, have developed pinhole leaks. The pitting matches the description of Type I pitting of copper, which has historically been attributed to water chemistry and to contaminants on the copper tubing surface. However, more recent studies attribute copper pitting to microbial induced corrosion (MIC). In order to test for microbes, the copper tubing was fixed in hexamethyldisilazane (HMDS), then the tops of the corrosion mounds were broken open, and the interior of the corrosion pits were examined with scanning electron microscopy (SEM). The analysis found that microbes resembling actinobacteria were deep inside the pits and wedged between the crystallographic planes of the corroded copper grains. The presence of actinobacteria confirms the possibility that the cause of this pitting corrosion was MIC. This observation provides better understanding and new methods for preventing the pitting of copper tubing in municipal water.

Copper Tube Pitting in Santa Fe Municipal Water Caused by Microbial Induced Corrosion

PubMed Central

Burleigh, Thomas D.; Gierke, Casey G.; Fredj, Narjes; Boston, Penelope J.

2014-01-01

Many copper water lines for municipal drinking water in Santa Fe, New Mexico USA, have developed pinhole leaks. The pitting matches the description of Type I pitting of copper, which has historically been attributed to water chemistry and to contaminants on the copper tubing surface. However, more recent studies attribute copper pitting to microbial induced corrosion (MIC). In order to test for microbes, the copper tubing was fixed in hexamethyldisilazane (HMDS), then the tops of the corrosion mounds were broken open, and the interior of the corrosion pits were examined with scanning electron microscopy (SEM). The analysis found that microbes resembling actinobacteria were deep inside the pits and wedged between the crystallographic planes of the corroded copper grains. The presence of actinobacteria confirms the possibility that the cause of this pitting corrosion was MIC. This observation provides better understanding and new methods for preventing the pitting of copper tubing in municipal water. PMID:28788679

Natural radionuclide content and radiological hazard associated with usage of quartzite sand samples from Ovacik-Silifke-Mersin open pit as building material in Turkey.

PubMed

Turhan, S; Aykamis, A S; Kiliç, A M

2009-09-01

Activity concentrations of (238)U, (232)Th, (226)Ra and (40)K in quartzite sand samples collected from the Ovacik-Silifke-Mersin open pit located in the East Mediterranean region of Turkey were determined by using a gamma-ray spectrometry technique. The mean activity concentrations of the (238)U, (232)Th, (226)Ra and (40)K in quartzite sand samples were found as 81.7 +/- 22.9 Bq kg(-1), 6.3 +/- 2.8 Bq kg(-1), 77.5 +/- 24.3 Bq kg(-1)and 140.0 +/- 124.1 Bq kg(-1), respectively. The gamma index (I(gamma)), the internal exposure index (I(alpha)), the indoor absorbed dose rate (D(in)) and the corresponding annual effective dose (H(in)) were evaluated for the public exposure to radiological hazard arising due to the use of quartzite sand samples as building material. The values of I(gamma), I(alpha), D(in) and H(in) ranged from 0.20 to 0.75, with a mean of 0.34 +/- 0.11, 0.23 to 0.77 with a mean of 0.39 +/- 0.12, 58.27 to 201.51 nGy h(-1) with a mean of 93.33 +/- 27.63 nGy h(-1) and 0.29 to 0.99 mSv with a mean of 0.46 +/- 0.14 mSv, respectively.

Laser induced breakdown spectroscopy (LIBS) as a rapid tool for material analysis

NASA Astrophysics Data System (ADS)

Hussain, T.; Gondal, M. A.

2013-06-01

Laser induced breakdown spectroscopy (LIBS) is a novel technique for elemental analysis based on laser-generated plasma. In this technique, laser pulses are applied for ablation of the sample, resulting in the vaporization and ionization of sample in hot plasma which is finally analyzed by the spectrometer. The elements are identified by their unique spectral signatures. LIBS system was developed for elemental analysis of solid and liquid samples. The developed system was applied for qualitative as well as quantitative measurement of elemental concentration present in iron slag and open pit ore samples. The plasma was generated by focusing a pulsed Nd:YAG laser at 1064 nm on test samples to study the capabilities of LIBS as a rapid tool for material analysis. The concentrations of various elements of environmental significance such as cadmium, calcium, magnesium, chromium, manganese, titanium, barium, phosphorus, copper, iron, zinc etc., in these samples were determined. Optimal experimental conditions were evaluated for improving the sensitivity of developed LIBS system through parametric dependence study. The laser-induced breakdown spectroscopy (LIBS) results were compared with the results obtained using standard analytical technique such as inductively couple plasma emission spectroscopy (ICP). Limit of detection (LOD) of our LIBS system were also estimated for the above mentioned elements. This study demonstrates that LIBS could be highly appropriate for rapid online analysis of iron slag and open pit waste.

Dewatering of the Jenkins open pit uranium mine

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

Straskraba, V.; Kissinger, L.E.

Mining of low grade uranium sandstones in the Jenkins open pit mine in the Shirley Basin, Wyoming was troubled by slope failures and wet conditions in the pit. Since the mine was expanding toward a river, the possibility of drainage from this river into the mine raised serious concern during the mine planning. A baseline hydrogeologic study was performed and dewatering measures were designed with the help of a numerical mathematical model. A combination of dewatering wells installed from the surface around the perimeter of the pit and horizontal drains in areas of high slope failure potential substantially improved themore » mining conditions and slope stability. This procedure consequently led to the successful ore recovery from the highly saturated sandstone strata. The development of drawdown during the dewatering of two separated aquifers in the overburden was close to that predicted by the model.« less

Dependence of Crystallographic Orientation on Pitting Corrosion Behavior of Ni-Fe-Cr Alloy 028

NASA Astrophysics Data System (ADS)

Zhang, LiNa; Szpunar, Jerzy A.; Dong, JianXin; Ojo, Olanrewaju A.; Wang, Xu

2018-06-01

The influence of crystallographic orientation on the pitting corrosion behavior of Ni-Fe-Cr alloy 028 was studied using a combination of X-ray diffraction (XRD), electron backscatter diffraction (EBSD), potentiodynamic polarization technique, and atomic force microscopy (AFM). The results show that there is anisotropy of pitting corrosion that strongly depends on crystallographic orientation of the surface plane. The distribution of pit density in a standard stereographic triangle indicates that the crystallographic planes close to {100} are more prone to pitting corrosion compared to planes {110} and {111}. The surface energy calculation of (001) and (111) shows that the plane with a high atomic packing density has a low surface energy with concomitant strong resistance to pitting corrosion. A correlation function between crystallographic orientation and pitting corrosion susceptibility suggests a method that not only predicts the pitting resistance of known textured materials, but also could help to improve corrosion resistance by controlling material texture.

Analytical data for waters of the Harvard Open Pit, Jamestown Mine, Tuolumne County, California, March 1998-September 1999

USGS Publications Warehouse

Ashley, R.P.; Savage, K.S.

2001-01-01

The Jamestown mine is located in the Jamestown mining district in western Tuolumne County, California (see Fig. 1). This district is one of many located on or near the Melones fault zone, a major regional suture in the Sierra Nevada foothills. The districts along the Melones fault comprise the Mother Lode gold belt (Clark, 1970). The Harvard pit is the largest of several open pits mined at the Jamestown site by Sonora Mining Corporation between 1986 and 1994 (Fig. 2; Algood, 1990). It is at the site of an historical mine named the Harvard that produced about 100,000 troy ounces of gold, mainly between 1906 and 1916 (Julihn and Horton, 1940). Sonora Mining mined and processed about 17,000,000 short tons of ore, with an overall stripping ratio of about 4.5:1, yielding about 660,000 troy ounces of gold (Nelson and Leicht, 1994). Most of this material came from the Harvard pit, which attained dimensions of about 2700 ft (830 m) in length, 1500 ft (460 m) in width, and 600 ft (185 m) in depth. The bottom of the pit is at an elevation of 870 ft (265 m). Since mining operations ceased in mid-1994, the open pit has been filling with water. As of November, 2000, lake level had reached an elevation of about 1170 ft (357 m). Water quality monitoring data gathered after mine closure showed rising levels of arsenic, sulfate, and other components in the lake, with particularly notable increases accompanying a period of rapid filling in 1995 (County of Tuolumne, 1998). The largest potential source for arsenic in the vicinity of the Harvard pit is arsenian pyrite, the most abundant sulfide mineral related to gold mineralization. A previous study of weathering of arsenian pyrite in similarly mineralized rocks at the Clio mine, in the nearby Jacksonville mining district, showed that arsenic released by weathering of arsenian pyrite is effectively attenuated by adsorption on goethite or coprecipitation with jarosite, depending upon the buffering capacity of the pyrite-bearing rock (Savage and others, 2000). Although jarosite would be expected to dissolve in water having the composition of the developing pit lake, iron oxyhydroxide species (ferrihydrite and goethite) would be stable, and strong partitioning of arsenic onto suspended particles or bottom sediments containing these iron phases would be expected. Arsenic release to the lake would not be expected until stratification develops, producing a reducing, non-circulating hypolimnion in which the iron phases would be destroyed by dissolution. The fact that arsenic concentrations increased rapidly before the pit lake was deep enough to stratify shows that arsenic may not be attenuated in the ways that the earlier Clio mine area study indicated, and suggested that our understanding of release and transport of arsenic in this environment is incomplete. Therefore, in 1997 we decided to study the chemical evolution of the Harvard pit lake as part of a project on environmental impacts of gold mining in the Sierra Nevada, and in early 1998 we developed a cooperative study with several of the investigators in the Stanford University Department of Geological and Environmental Sciences who had done the Clio study. The U.S. Geological Survey portion of the project has been funded by the Mineral Resources Program. It is anticipated that a better understanding of the release and transport of arsenic into the Harvard pit lake and its accumulation there will contribute to more accurate predictions of arsenic release from weathering of sulfide-bearing rocks exposed by mining or other activities or events, and to better forecasts of pit lake evolution in this and similar environments, leading to more effective monitoring and mitigation strategies. An accurate predictive model is needed for the Harvard pit lake to forecast trends in metal concentrations, particularly arsenic, and also concentrations of major cations and anions. As the lake approaches pre-mining groundwater levels the lake water could move down the hydrologic gradient to the southeast into domestic wells, and could also affect the surface water of Woods Creek (see Figures 1-3). This report presents data for water samples collected from March, 1998 through September, 1999. Selected preliminary data for the pit lake for the 1998 calendar year have been reported (Savage and others, 2000).

Group traction drive as means to increase energy efficiency of lokomotives of open-pit transport

NASA Astrophysics Data System (ADS)

Antipin, D. Ya; Izmerov, O. V.; Bishutin, S. G.; Kobishchanov, V. V.

2017-10-01

Questions of possible use of a group drive for locomotives of an open-pit transport are considered. The possibility of a significant reduction of traction costs in the case of a combination of a group traction drive with devices for the non-inertial regulation of the coefficient of friction between the wheel and the rail has been shown, and new patentable solutions have been proposed.

The Key Factors Analysis of Palisades Temperature in Deep Open-pit Mine

NASA Astrophysics Data System (ADS)

Wang, Yuan; Du, Cuifeng; Jin, Wenbo; Wang, Puyu

2018-01-01

In order to study the key factors of palisades temperature field in a deep open-pit mine in the natural environment, the influence of natural factors on the palisades temperature in a deep open-pit mine were analysed based on the principle of heat transfer. Four typical places with different ways of solar radiation were selected to carry out the field test. The results show that solar radiation, atmospheric temperature, and wind speed are three main factors affecting the temperature of palisades and that the direct sunlight plays a leading role. The time period of the sun shining directly on the shady slope of the palisades is short because of blocking effect, whose temperature changes in a smaller scale. At the same time, the sun slope of the palisades suffers from the solar radiation for a long time, whose temperature changes in a larger scale, and the variation is similar to the air temperature.

The effect of oxide film properties on the corrosion behavior of SiC/Al metal-matrix composites

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

Golledge, S.L.

1991-01-01

Oxide growth on pure aluminum, aluminum alloy 6061, and the aluminum-based metal matrix composite SiC/AA6061 was studied, and the properties of the oxides related to the pit-initiation behavior of the materials. The objectives of the work were to identify the effect of alloying elements and SiC reinforcement on the oxide film, and to better understand how the oxide properties control pit initiation behavior. To this end, electrochemical and optical studies of the materials were carried out in a buffered sodium/boric acid solution at pH values of 8.4 and 7.2. The alloy and metal-matrix composite showed a slightly lesser tendency tomore » pit than pure aluminum, as measured by the pitting potential. The oxide on the composite was less resistant to pit initiation, and was found to exhibit slower repassivation rates than the other materials. The repassivation behavior and resistance to pit initiation were quite similar in the case of the alloy and the pure aluminum. Induction times for pit initiation were consistent with the predictions of Heusler's model for the breakdown of passivity.« less

Earth Observations taken by the Expedition 13 crew

NASA Image and Video Library

2006-08-02

ISS013-E-63766 (2 Aug. 2006) --- Berkeley Pit and Butte, Montana are featured in this image photographed by an Expedition 13 crewmember on the International Space Station. The city of Butte, Montana has long been a center of mining activity. Underground mining of copper began in Butte in the 1870s, and by 1901 underground workings had extended to the groundwater table. Thus began the creation of an intricate complex of underground drains and pumps to lower the groundwater level and continue the extraction of copper. Water extracted from the mines was so rich in dissolved copper sulfate that it was also "mined" (by chemical precipitation) for the copper it contained. In 1955, the Anaconda Copper Mining Company began open-pit mining for copper in what is now know as the Berkeley Pit (dark oblong area in center). The mine took advantage of the existing subterranean drainage and pump network to lower groundwater until 1982, when the new owner ARCO suspended operations at the mine. The groundwater level swiftly rose, and today water in the Pit is more than 900 feet deep. Many features of the mine workings are visible in this image such as the many terraced levels and access roadways of the open mine pits (gray and tan sculptured surfaces). A large gray tailings pile of waste rock and an adjacent tailings pond are visible to the north of the Berkeley Pit. Color changes in the tailings pond are due primarily to changing water depth. The Berkeley Pit is listed as a federal Superfund site due to its highly acidic water, which contains high concentrations of metals such as copper and zinc. The Berkeley Pit receives groundwater flowing through the surrounding bedrock and acts as a "terminal pit" or sink for these heavy metal-laden waters. Ongoing efforts include regulation of water flow into the pit to reduce filling of the Pit and potential release of contaminated water into local aquifers or surface streams.

Contaminant dispersion at the rehabilitated Mary Kathleen uranium mine, Australia

NASA Astrophysics Data System (ADS)

Lottermoser, B. G.; Ashley, P. M.; Costelloe, M. T.

2005-09-01

This study reports on the transfer of contaminants from waste rock dumps and mineralised ground into soils, sediments, waters and plants at the rehabilitated Mary Kathleen uranium mine in semi-arid northwest Queensland. Numerous waste rock dumps were partly covered with benign soil and the open pit mine was allowed to flood. The mineralised and waste calc-silicate rock in the open pit and dumps has major (>1 wt%) Ca, Fe and Mg, minor (>1,000 ppm) Ce, La, Mn, P and S, subminor (>100 ppm) Ba, Cu, Th and U, and trace (<100 ppm) As, Ni, Pb, Y and Zn values. Consequently, chemical and physical weathering processes have acted on waste rock and on rock faces within the open pit, mobilising many elements and leading to their dispersion into soils, stream sediments, pit water and several plant species. Chemical dispersion is initiated by sulfide mineral breakdown, generation of sulfuric acid and formation of several soluble, transient sulfate minerals as evaporative efflorescent precipitates. Radiation doses associated with the open pit average 5.65 mSv year-1; waste dumps commonly have lower values, especially where soil-covered. Surface pit water is slightly acid, with high sulfate values accompanied by levels of U, Cu and Ni close to or above Australian water guideline values for livestock. Dispersion of U and related elements into soils and stream sediments occurs by physical (erosional) processes and from chemical precipitation. Plants growing in the mine void, on waste dumps and contaminated soil display evidence of biological uptake of U, LREE, Cu and Th and to a lesser degree of As, Ni, Pb, Y and Zn, with values being up to 1-2 orders of magnitude above background sites for the same species. Although rehabilitation procedures have been partly successful in reducing dispersion of U and related elements into the surrounding environment, it is apparent that 20 years after rehabilitation, there is significant physical and chemical mobility, including transfer into plants.

Trace metal depositional patterns from an open pit mining activity as revealed by archived avian gizzard contents.

PubMed

Bendell, L I

2011-02-15

Archived samples of blue grouse (Dendragapus obscurus) gizzard contents, inclusive of grit, collected yearly between 1959 and 1970 were analyzed for cadmium, lead, zinc, and copper content. Approximately halfway through the 12-year sampling period, an open-pit copper mine began activities, then ceased operations 2 years later. Thus the archived samples provided a unique opportunity to determine if avian gizzard contents, inclusive of grit, could reveal patterns in the anthropogenic deposition of trace metals associated with mining activities. Gizzard concentrations of cadmium and copper strongly coincided with the onset of opening and the closing of the pit mining activity. Gizzard zinc and lead demonstrated significant among year variation; however, maximum concentrations did not correlate to mining activity. The archived gizzard contents did provide a useful tool for documenting trends in metal depositional patterns related to an anthropogenic activity. Further, blue grouse ingesting grit particles during the time of active mining activity would have been exposed to toxicologically significant levels of cadmium. Gizzard lead concentrations were also of toxicological significance but not related to mining activity. This type of "pulse" toxic metal exposure as a consequence of open-pit mining activity would not necessarily have been revealed through a "snap-shot" of soil, plant or avian tissue trace metal analysis post-mining activity. Copyright © 2010 Elsevier B.V. All rights reserved.

Detecting Cavitation Pitting Without Disassembly

NASA Technical Reports Server (NTRS)

Barkhoudarian, S.

1986-01-01

Technique for detecting cavitation pitting in pumps, turbines, and other machinery uses low-level nuclear irradiation. Isotopes concentrated below surface emit gamma radiation, a portion of which is attenuated by overlying material. Where there are cavitation pits, output of gamma-ray detector fluctuates as detector is scanned near pits. Important to detect cavitation pits because nozzle, turbine blade, or other pump component weakened by cavitation could fail catastrophically and cause machine to explode.

The Pits

NASA Technical Reports Server (NTRS)

2006-01-01

8 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a portion of a pit chain on the lower, northern flank of the giant martian volcano, Arsia Mons. Pits such as these commonly form as a result of collapse of surface materials into a subsurface void, possibly along a fault or into an old lava tube. The layered material, exposed near the top of several of the pits, is shedding house-sized boulders which can be seen resting on the sloping sidewalls and floors of many of the pits.

Location near: 6.7oS, 120.1oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Summer

Ecohydrology applications to ecosystem reconstruction after oil-sand mining

NASA Astrophysics Data System (ADS)

Mendoza, Carl; Devito, Kevin

2014-05-01

Oil-sand deposits in northeast Alberta, Canada comprise some of the world's largest oil reserves. Open-pit mining of these resources leads to waste-rock piles, tailings ponds and open pits that must be reclaimed to "equivalent landscape capability", with viable forests and wetlands, using only native vegetation. Understanding ecohydrological processes in natural systems is critical for designing the necessary landforms and landscapes. A challenge is the cold, sub-humid climate, with highly variable precipitation. Furthermore, there are competing demands, needs or uses for water, in both quantity and quality, for reclamation and sustainability of forestlands, wetlands and end-pit lakes. On average there is a potential water deficit in the region, yet wetlands cover half of the undisturbed environment. Water budget analyses demonstrate that, although somewhat unpredictable and uncontrollable, the magnitude and timing of water delivery largely control water storage and conservation within the landscape. The opportunity is to design and manipulate these reconstructed landscapes so that water is stored and conserved, and water quality is naturally managed. Heterogeneous geologic materials can be arranged and layered, and landforms sculpted, to minimize runoff, enhance infiltration, and promote surface and subsurface storage. Similarly, discharge of poor quality water can be minimized or focused. And, appropriate vegetation choices are necessary to conserve water on the landscape. To achieve these ends, careful attention must be paid to the entire water budget, the variability in its components, interconnections between hydrologic units, in both space and time, and coupled vegetation processes. To date our knowledge is guided primarily by natural analogues. To move forward, it is apparent that numerous priorities and constraints, which are potentially competing, must be addressed. These include geotechnical and operational requirements, material limitations or excesses, time, money and performance expectations. Careful landform design and integration of ecohydrological principles can be used to address some of these issues.

Central Pit Crater

NASA Image and Video Library

2015-11-13

Crater floors can have a range of features, from flat to a central peak or a central pit. This image from NASA 2001 Mars Odyssey spacecraft shows an unnamed crater in Terra Sabaea has a central pit. This unnamed crater in Terra Sabaea has a central pit. The different floor features develop do due several factors, including the size of the impactor, the geology of the surface material and the geology of the materials at depth. Orbit Number: 60737 Latitude: 22.3358 Longitude: 61.2019 Instrument: VIS Captured: 2015-08-23 20:13 http://photojournal.jpl.nasa.gov/catalog/PIA20092

On the influence of etch pits in the overall dissolution rate of apatite basal sections

NASA Astrophysics Data System (ADS)

Alencar, Igor; Guedes, Sandro; Palissari, Rosane; Hadler, Julio C.

2015-09-01

Determination of efficiencies for particle detection plays a central role for proper estimation of reaction rates. If chemical etching is employed in the revelation of latent particle tracks in solid-state detectors, dissolution rates and etchable lengths are important factors governing the revelation and observation. In this work, the mask method, where a reference part of the sample is protected during dissolution, was employed to measure step heights in basal sections of apatite etched with a nitric acid, HNO, solution at a concentration of 1.1 M and a temperature of 20 °C. We show a drastic increase in the etching velocity as the number of etch pits in the surface augments, in accordance with the dissolution stepwave model, where the outcrop of each etch pit generates a continuous sequence of stepwaves. The number of etch pits was varied by irradiation with neutrons and perpendicularly incident heavy ions. The size dependence of the etch-pit opening with etching duration for ion (200-300 MeV 152Sm and 238U) tracks was also investigated. There is no distinction for the etch pits between the different ions, and the dissolution seems to be governed by the opening velocity when a high number of etch pits are present in the surface. Measurements of the etchable lengths of these ion tracks show an increase in these lengths when samples are not pre-annealed before irradiation. We discuss the implications of these findings for fission-track modelling.

Public exposure to hazards associated with natural radioactivity in open-pit mining in Ghana.

PubMed

Darko, E O; Faanu, A; Awudu, A R; Emi-Reynolds, G; Yeboah, J; Oppon, O C; Akaho, E H K

2010-01-01

The results of studies carried out on public exposure contribution from naturally occurring radioactive materials (NORMS) in two open-pit mines in the Western and Ashanti regions of Ghana are reported. The studies were carried out under International Atomic Energy Agency-supported Technical Co-operation Project GHA/9/005. Measurements were made on samples of water, soil, ore, mine tailings and air using gamma spectrometry. Solid-state nuclear track detectors were used for radon concentration measurements. Survey was also carried out to determine the ambient gamma dose rate in the vicinity of the mines and surrounding areas. The effective doses due to external gamma irradiation, ingestion of water and inhalation of radon and ore dusts were calculated for the two mines. The average annual effective dose was found to be 0.30 +/- 0.06 mSv. The result was found to be within the levels published by other countries. The study provides a useful information and data for establishing a comprehensive framework to investigate other mines and develop guidelines for monitoring and control of NORMS in the mining industry and the environment as a whole in Ghana.

Cover design for radioactive and AMD-producing mine waste in the Ronneburg area, eastern Thuringia.

PubMed

Gatzweiler, R; Jahn, S; Neubert, G; Paul, M

2001-01-01

At the former uranium mining site of Ronneburg, large scale underground and open pit mining for nearly 40 years resulted in a production of about 113,000 tonnes of uranium and about 200 million cubic metres of mine waste. In their present state, these materials cause risks to human health and strong environmental impacts and therefore demand remedial action. The remediation options available are relocation of mine spoil into the open pit and on site remediation by landscaping/contouring, placement of a cover and revegetation. A suitable vegetated cover system combined with a surface water drainage system provides long-term stability against erosion and reduces acid generation thereby meeting the main remediation objectives which are long-term reduction of radiological exposure and contaminant emissions and recultivation. The design of the cover system includes the evaluation of geotechnical, radiological, hydrological, geochemical and ecological criteria and models. The optimized overall model for the cover system has to comply with general conditions as, e.g. economic efficiency, public acceptance and sustainability. Most critical elements for the long-term performance of the cover system designed for the Beerwalde dump are the barrier system and its long-term integrity and a largely self-sustainable vegetation.

Initation of pitting corrosion in martensitic stainless steels. [17-4PH; 13-8Mo; Custom 450

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

Cieslak, W.R.; Semarge, R.E.; Bovard, F.S.

1986-01-01

The form of localized corrosion known as pitting often initiates preferentially at microstructural inhomogeneities. The pit initiation resistance, therefore, is controlled by the characteristics of the initiation sites, rather than by the bulk material composition. This investigation correlates the pit initiation resistance, as measured by critical pitting potentials, with preferred pit initiation sites for 3 martensitic stainless steels. Pit initiation sites are determined by secondary electron (SE) and backscattered electron (BSE) imaging and energy dispersive and wavelength dispersive spectrometries (EDS and WDS) with a scalling electron microscope (SEM) and an electron probe microanalyzer (EPMA).

Chiquicamata Mine, Chile

NASA Image and Video Library

2016-08-24

Chuquicamata, in Chile's Atacama Desert, is the largest open pit copper mine in the world, by excavated volume. The copper deposits were first exploited in pre-Hispanic times. Open pit mining began in the early 20th century when a method was developed to work low grade oxidized copper ores. The image was acquired September 2, 2007, covers an area of 19.5 by 29.3 km, and is located at 22.1 degrees south, 68.9 degrees west. http://photojournal.jpl.nasa.gov/catalog/PIA20973

The comparative morphology of pit organs in elasmobranchs.

PubMed

Peach, M B; Marshall, N J

2009-06-01

The pit organs of elasmobranchs (sharks, skates and rays) are free neuromasts of the mechanosensory lateral line system. Pit organs, however, appear to have some structural differences from the free neuromasts of bony fishes and amphibians. In this study, the morphology of pit organs was investigated by scanning electron microscopy in six shark and three ray species. In each species, pit organs contained typical lateral line hair cells with apical stereovilli of different lengths arranged in an "organ-pipe" configuration. Supporting cells also bore numerous apical microvilli taller than those observed in other vertebrate lateral line organs. Pit organs were either covered by overlapping denticles, located in open grooves bordered by denticles, or in grooves without associated denticles. The possible functional implications of these morphological features, including modification of water flow and sensory filtering properties, are discussed.

Identifying and Reducing Health Risks Associated with Open-Air Burn Pits

DTIC Science & Technology

2013-04-01

product to the base or local nationals to add nutrients to improve the soil .”19 While recycling and composting does require additional manpower, the...burn pits and to contaminated water at military bases at literally hundreds of locations throughout Iraq and Afghanistan.”21 All of the separate...proximity to smoke emanating from such burn pits. As to military personnel, there are a number of statutory remedies available to them, and with 6

Study on sand particles creep model and open pit mine landslide mechanism caused by sand fatigue liquefaction

NASA Astrophysics Data System (ADS)

Du, Dong-Ning; Wang, Lai-Gui; Zhang, Xiang-Dong; Zhang, Shu-Kun

2017-06-01

The sand particles in the sand - rock composite slope of the open pit mine occurs creep deformation and fatigue liquefaction under the action of vehicle load vibration and hydraulic gradient, which causes landslide geological disasters and it destroys the surface environment. To reveal the mechanism, a mechanics model based on the model considering the soil structural change with a new “plastic hinge” element is developed, to improve its constitutive and creep curve equations. Data from sand creep experiments are used to identify the parameters in the model and to validate the model. The results show that the mechanical model can describe the rotation progress between the sand particles, disclose the negative acceleration creep deformation stage during the third phase, and require fewer parameters while maintaining accuracy. It provides a new creep model considering rotation to analyze sand creep mechanism, which provides a theoretical basis for revealing the open pit mine landslide mechanism induced by creep deformation and fatigue liquefaction of sandy soil.

Deformation processes within wheel-rail adhesion in contact area

NASA Astrophysics Data System (ADS)

Albagachiev, A. Yu; Keropyan, A. M.

2018-03-01

The study of working surface deformation during interaction of open-pit locomotive tires allowed defining outstanding features of phenomena occurring in the contact area of interacting surfaces. It was found that processes typical for plastic saturated contact occur in the area of wheel-rail interaction of industrial railway transport. In case of plastic deformation exposed to heavy loads typical for open-pit locomotives, upon all rough surfaces of the contour contact area being fully deformed, the frame on which they are found is exposed to plastic deformation. Plastic deformation of roughness within the contact area of interacting surfaces leads to the increase in the actual area of their contact and, therefore, increases the towing capacity of mining machines. Finally, the available data on deformation characteristics with regard to processes occurring in the contact area of wheel-rail interaction will allow making theoretical forecasts on the expected design value of friction coefficient and, therefore, the towing capacity of open-pit locomotives.

Real -time dispatching modelling for trucks with different capacities in open pit mines / Modelowanie w czasie rzeczywistym przewozów ciężarówek o różnej ładowności w kopalni odkrywkowej

NASA Astrophysics Data System (ADS)

Ahangaran, Daryoush Kaveh; Yasrebi, Amir Bijan; Wetherelt, Andy; Foster, Patrick

2012-10-01

Application of fully automated systems for truck dispatching plays a major role in decreasing the transportation costs which often represent the majority of costs spent on open pit mining. Consequently, the application of a truck dispatching system has become fundamentally important in most of the world's open pit mines. Recent experiences indicate that by decreasing a truck's travelling time and the associated waiting time of its associated shovel then due to the application of a truck dispatching system the rate of production will be considerably improved. Computer-based truck dispatching systems using algorithms, advanced and accurate software are examples of these innovations. Developing an algorithm of a computer- based program appropriated to a specific mine's conditions is considered as one of the most important activities in connection with computer-based dispatching in open pit mines. In this paper the changing trend of programming and dispatching control algorithms and automation conditions will be discussed. Furthermore, since the transportation fleet of most mines use trucks with different capacities, innovative methods, operational optimisation techniques and the best possible methods for developing the required algorithm for real-time dispatching are selected by conducting research on mathematical-based planning methods. Finally, a real-time dispatching model compatible with the requirement of trucks with different capacities is developed by using two techniques of flow networks and integer programming.

Airborne Hazards and Open Burn Pit Registry

MedlinePlus

... Burn Pit Registry requires a common web browser technology to guide you through the registry questionnaire. You may try a different browser, or you may try from a different computer. You may also see this problem if you are in a high security environment where this is disabled by a network policy. ...

Progressive Retinal Nerve Fiber Layer Atrophy Associated With Enlarging Peripapillary Pit.

PubMed

Lee, Eun Ji; Kim, Tae-Woo

2017-02-01

To report a case in which progressive retinal nerve fiber layer (RNFL) atrophy was observed along with enlargement of the peripapillary pit. A 34-year-old male was diagnosed with primary open-angle glaucoma and followed up for 4 years with regular ophthalmic examinations. Both eyes were myopic (-10 D, OD and -10.5 D, OS), and untreated intraocular pressures were 18 mm Hg (OD) and 16 mm Hg (OS). A subtle depression of the superotemporal peripapillary area was deepened and emerged as a peripapillary pit during the follow-up period. With the enlargement of the peripapillary pit, a RNFL defect at the location of pit widened and thinned continuously. The enlargement of the pit was documented by the spectral-domain optical coherence tomography posterior pole scanning. Progressive RNFL atrophy was observed with enlargement of the peripapillary pit. The finding suggests that tensile stress derived from the scleral stretching may have significant influence on the integrity of the RNFL.

Trabeculotomy combined with phacoemulsification and implantation of an intraocular lens for the treatment of primary open-angle glaucoma and coexisting cataract.

PubMed

Tanihara, H; Honjo, M; Inatani, M; Honda, Y; Ogino, N; Ueno, S; Negi, A; Ichioka, H; Mizoguchi, T; Matsumura, M; Nagata, M

1997-10-01

The authors previously reported the usefulness of trabeculotomy ab externo for the treatment of primary open-angle glaucoma in adult patients. In an attempt to elucidate the long-term risk-to-benefit ratio of this surgical modality in combination with cataract surgery, the authors conducted a retrospective study of the surgical effects and complications of a triple procedure: phacoemulsification, implantation (of an intraocular lens), and trabeculotomy (PIT). The authors conducted a retrospective study of patients treated with PIT at multiple hospitals. Intraocular pressure (IOP) and visual function data were obtained from patients after PIT as an initial surgical treatment in cases where antiglaucoma medications failed to resolve uncontrolled IOP (higher than 21 mm Hg). Included in this study were 96 eyes of 64 patients with primary open-angle glaucoma and coexisting cataract. The mean follow-up period was 22.6 +/- 14.7 months (range 3-56 months). In 94 (98%) of the 96 eyes, the IOP was well controlled, having achieved a level of 21 mm Hg or lower at the final examinations. The mean preoperative IOP of the 33 eyes that underwent the triple procedure using a single flap method (PIT-I) was 24.3 +/- 3.9 mm Hg, with an average of 2.1 +/- 1.1 medications. At the final examinations, the mean IOP had dropped to 16.0 +/- 1.2 mm Hg, with an average of 1.2 +/- 1.2 medications. The mean preoperative IOP of the 63 eyes that underwent the triple procedure using a double flap method (PIT-II) was 26.2 +/- 6.2 mm Hg, with an average of 1.9 +/- 1.2 medications. At the final examination, the mean IOP for this group was 15.6 +/- 2.9 mm Hg, with an average of 1.0 +/- 0.9 medications. The long-term results from this multicenter study showed that the triple procedure, PIT, can be useful and effective as an initial surgical treatment for open-angle glaucoma in glaucoma patients with coexisting cataract.

Distribution, morphology, and origins of Martian pit crater chains

NASA Astrophysics Data System (ADS)

Wyrick, Danielle; Ferrill, David A.; Morris, Alan P.; Colton, Shannon L.; Sims, Darrell W.

2004-06-01

Pit craters are circular to elliptical depressions found in alignments (chains), which in many cases coalesce into linear troughs. They are common on the surface of Mars and similar to features observed on Earth and other terrestrial bodies. Pit craters lack an elevated rim, ejecta deposits, or lava flows that are associated with impact craters or calderas. It is generally agreed that the pits are formed by collapse into a subsurface cavity or explosive eruption. Hypotheses regarding the formation of pit crater chains require development of a substantial subsurface void to accommodate collapse of the overlying material. Suggested mechanisms of formation include: collapsed lava tubes, dike swarms, collapsed magma chamber, substrate dissolution (analogous to terrestrial karst), fissuring beneath loose material, and dilational faulting. The research described here is intended to constrain current interpretations of pit crater chain formation by analyzing their distribution and morphology. The western hemisphere of Mars was systematically mapped using Mars Orbiter Camera (MOC) images to generate ArcView™ Geographic Information System (GIS) coverages. All visible pit crater chains were mapped, including their orientations and associations with other structures. We found that pit chains commonly occur in areas that show regional extension or local fissuring. There is a strong correlation between pit chains and fault-bounded grabens. Frequently, there are transitions along strike from (1) visible faulting to (2) faults and pits to (3) pits alone. We performed a detailed quantitative analysis of pit crater morphology using MOC narrow angle images, Thermal Emission Imaging System (THEMIS) visual images, and Mars Orbiter Laser Altimeter (MOLA) data. This allowed us to determine a pattern of pit chain evolution and calculate pit depth, slope, and volume. Volumes of approximately 150 pits from five areas were calculated to determine volume size distribution and regional trends. The information collected in the study was then compared with non-Martian examples of pit chains and physical analog models. We evaluated the various mechanisms for pit chain development based on the data collected and conclude that dilational normal faulting and sub-vertical fissuring provide the simplest and most comprehensive mechanisms to explain the regional associations, detailed geometry, and progression of pit chain development.

Additional disturbances as a beneficial tool for restoration of post-mining sites: a multi-taxa approach.

PubMed

Řehounková, Klára; Čížek, Lukáš; Řehounek, Jiří; Šebelíková, Lenka; Tropek, Robert; Lencová, Kamila; Bogusch, Petr; Marhoul, Pavel; Máca, Jan

2016-07-01

Open interior sands represent a highly threatened habitat in Europe. In recent times, their associated organisms have often found secondary refuges outside their natural habitats, mainly in sand pits. We investigated the effects of different restoration approaches, i.e. spontaneous succession without additional disturbances, spontaneous succession with additional disturbances caused by recreational activities, and forestry reclamation, on the diversity and conservation values of spiders, beetles, flies, bees and wasps, orthopterans and vascular plants in a large sand pit in the Czech Republic, Central Europe. Out of 406 species recorded in total, 112 were classified as open sand specialists and 71 as threatened. The sites restored through spontaneous succession with additional disturbances hosted the largest proportion of open sand specialists and threatened species. The forestry reclamations, in contrast, hosted few such species. The sites with spontaneous succession without disturbances represent a transition between these two approaches. While restoration through spontaneous succession favours biodiversity in contrast to forestry reclamation, additional disturbances are necessary to maintain early successional habitats essential for threatened species and open sand specialists. Therefore, recreational activities seem to be an economically efficient restoration tool that will also benefit biodiversity in sand pits.

The mechanism of erosion of metallic materials under cavitation attack

NASA Technical Reports Server (NTRS)

Rao, B. C. S.; Buckley, D. H.

1985-01-01

The mean depth of penetration rates (MDPRs) of eight polycrystalline metallic materials, Al 6061-T6, Cu, brass, phosphor bronze, Ni, Fe, Mo, and Ti-5Al-2.5Sn exposed to cavitation attack in a viscous mineral oil with a 20 kHz ultrasonic oscillator vibrating at 50 micron amplitude are reported. The titanium alloy followed by molybdenum have large incubation periods and small MDPRs. The incubation periods correlate linearly with the inverse of hardness and the average MDPRs correlate linearly with the inverse of tensile strength of materials. The linear relationships yield better statistical parameters than geometric and exponential relationships. The surface roughness and the ratio of pit depth to pit width (h/a) increase with the duration of cavitation attack. The ratio h/a varies from 0.1 to 0.8 for different materials. Recent investigations (20) using scanning electron microscopy to study deformation and pit formation features are briefly reviewed. Investigations with single crystals indicate that the geometry of pits and erosion are dependent on their orientation.

Application of 3D Laser Scanning Technology in Inspection and Dynamic Reserves Detection of Open-Pit Mine

NASA Astrophysics Data System (ADS)

Hu, Zhumin; Wei, Shiyu; Jiang, Jun

2017-10-01

The traditional open-pit mine mining rights verification and dynamic reserve detection means rely on the total station and RTK to collect the results of the turning point coordinates of mining surface contours. It resulted in obtaining the results of low precision and large error in the means that is limited by the traditional measurement equipment accuracy and measurement methods. The three-dimensional scanning technology can obtain the three-dimensional coordinate data of the surface of the measured object in a large area at high resolution. This paper expounds the commonly used application of 3D scanning technology in the inspection and dynamic reserve detection of open mine mining rights.

Electrochemical analysis of the corrosion inhibition effect of trypsin complex on the pitting corrosion of 420 martensitic stainless steel in 2M H2SO4 solution.

PubMed

Loto, Roland Tolulope

2018-01-01

Inhibition effect of trypsin complex (TC) on the pitting corrosion of martensitic stainless steel (type 420) in 1M H2SO4 solution was studied with potentiodynamic polarization, open circuit potential measurement and optical microscopy. TC reduced the corrosion rate of the steel with maximum inhibition efficiency of 80.75%. Corrosion potential shifted anodically due to the electrochemical action of TC. The pitting potential increased from 1.088VAg/AgCl (3M) at 0% TC to 1.365VAg/AgCl(3M) at 4% TC. TC shifts the open circuit corrosion potential from -0.270s at 0% TC concentration to -0.255V at 5% TC. The compound completely adsorbed onto the steel according to Langmuir, Frumkin and Temkin isotherms. ATF-FTIR spectroscopy confirmed the inhibition mode to be through surface coverage. Thermodynamic calculations showed physisorption molecular interaction. Corrosion pits are present on the uninhibited 420 morphology in comparison to TC inhibited surface which slightly deteriorated.

Electrochemical analysis of the corrosion inhibition effect of trypsin complex on the pitting corrosion of 420 martensitic stainless steel in 2M H2SO4 solution

PubMed Central

Loto, Roland Tolulope

2018-01-01

Inhibition effect of trypsin complex (TC) on the pitting corrosion of martensitic stainless steel (type 420) in 1M H2SO4 solution was studied with potentiodynamic polarization, open circuit potential measurement and optical microscopy. TC reduced the corrosion rate of the steel with maximum inhibition efficiency of 80.75%. Corrosion potential shifted anodically due to the electrochemical action of TC. The pitting potential increased from 1.088VAg/AgCl (3M) at 0% TC to 1.365VAg/AgCl(3M) at 4% TC. TC shifts the open circuit corrosion potential from -0.270s at 0% TC concentration to -0.255V at 5% TC. The compound completely adsorbed onto the steel according to Langmuir, Frumkin and Temkin isotherms. ATF-FTIR spectroscopy confirmed the inhibition mode to be through surface coverage. Thermodynamic calculations showed physisorption molecular interaction. Corrosion pits are present on the uninhibited 420 morphology in comparison to TC inhibited surface which slightly deteriorated. PMID:29672541

Evidence for the interior evolution of Ceres from geologic analysis of fractures

USGS Publications Warehouse

Scully, Jennifer E. C.; Buczkowski, Debra; Schmedemann, Nico; Raymond, Carol A.; Castillo-Rogez, Julie C.; Scott King,; Bland, Michael T.; Ermakov, Anton; O'Brien, D.P.; Marchi, S.; Longobardo, A.; Russell, C.T.; Fu, R.R.; Neveu, M.

2017-01-01

Ceres is the largest asteroid belt object, and the Dawn spacecraft observed Ceres since 2015. Dawn observed two morphologically distinct linear features on Ceres's surface: secondary crater chains and pit chains. Pit chains provide unique insights into Ceres's interior evolution. We interpret pit chains called the Samhain Catenae as the surface expression of subsurface fractures. Using the pit chains' spacings, we estimate that the localized thickness of Ceres's fractured, outer layer is approximately ≥58 km, at least ~14 km greater than the global average. We hypothesize that extensional stresses, induced by a region of upwelling material arising from convection/diapirism, formed the Samhain Catenae. We derive characteristics for this upwelling material, which can be used as constraints in future interior modeling studies. For example, its predicted location coincides with Hanami Planum, a high-elevation region with a negative residual gravity anomaly, which may be surficial evidence for this proposed region of upwelling material.

Collapse Pits

NASA Technical Reports Server (NTRS)

2005-01-01

24 April 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a large and several small pits formed by collapse along the trend of a fault system in the Uranius Fossae region of Mars. Running diagonal from middle-right toward lower left is a trough that intersects the pit. The trough is a typical graben formed by faulting as the upper crust of Mars split and pulled apart at this location. The opening of the graben also led to formation of the collapse pits.

Location near: 26.2oN, 88.7oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Summer

Open pit mining profit maximization considering selling stage and waste rehabilitation cost

NASA Astrophysics Data System (ADS)

Muttaqin, B. I. A.; Rosyidi, C. N.

2017-11-01

In open pit mining activities, determination of the cut-off grade becomes crucial for the company since the cut-off grade affects how much profit will be earned for the mining company. In this study, we developed a cut-off grade determination mode for the open pit mining industry considering the cost of mining, waste removal (rehabilitation) cost, processing cost, fixed cost, and selling stage cost. The main goal of this study is to develop a model of cut-off grade determination to get the maximum total profit. Secondly, this study is also developed to observe the model of sensitivity based on changes in the cost components. The optimization results show that the models can help mining company managers to determine the optimal cut-off grade and also estimate how much profit that can be earned by the mining company. To illustrate the application of the models, a numerical example and a set of sensitivity analysis are presented. From the results of sensitivity analysis, we conclude that the changes in the sales price greatly affects the optimal cut-off value and the total profit.

Earth Observations taken by the Expedition 22 Crew

NASA Image and Video Library

2010-01-14

ISS022-E-026137 (14 Jan. 2010) --- Open Pit Mines in southern Arizona are featured in this image photographed by an Expedition 22 crew member on the International Space Station. The State of Arizona is the United States? largest producer of the metal copper, primarily mined from ore bodies known as porphyry copper deposits. Copper is a good conductor of electricity and heat, and is a vital element of virtually all of our electronic devices and components. A porphyry copper deposit is a geological structure formed by crystal-rich magma moving upwards through pre-existing rock layers. As the magma cools and crystallizes, it forms an igneous rock with large crystals embedded in a fine-grained matrix, known as porphyry. Hot fluids circulate through the magma and surrounding rocks via fractures, depositing copper-bearing and other minerals in characteristic spatial patterns that signal the nature of the ore body to a geologist. The most common approach to extracting metal-bearing ore from a porphyry copper deposit is by open-pit mining. For more details, please refer to http://earth.jsc.nasa.gov/EarthObservatory/OpenPitMinesSouthernArizona.htm.

Stress state of rock mass under open pit mining in the influence zone of tectonic disturbances (in terms of the Oktorkoi Fault, North Tien Shan)

NASA Astrophysics Data System (ADS)

Kozhogulov, KCh; Nikolskaya, OV; Rybin, AK; Kuzikov, SI

2018-03-01

The qualitative connection between the crack growth direction and the orientation of the main axes of horizontal deformations in rocks mass in the area of the Boordin gold ore province is revealed. The effect of the rock mass quality (RQD) and contact conditions of crack surfaces on the stability index of pit wall rock mass is evaluated, and the influence of the rock mass quality index on the pit wall stability is determined.

Distribution, formation mechanisms, and significance of lunar pits

NASA Astrophysics Data System (ADS)

Wagner, Robert V.; Robinson, Mark S.

2014-07-01

Lunar Reconnaissance Orbiter Camera images reveal the presence of steep-walled pits in mare basalt (n = 8), impact melt deposits (n = 221), and highland terrain (n = 2). Pits represent evidence of subsurface voids of unknown extents. By analogy with terrestrial counterparts, the voids associated with mare pits may extend for hundreds of meters to kilometers in length, thereby providing extensive potential habitats and access to subsurface geology. Because of their small sizes relative to the local equilibrium crater diameters, the mare pits are likely to be post-flow features rather than volcanic skylights. The impact melt pits are indirect evidence both of extensive subsurface movement of impact melt and of exploitable sublunarean voids. Due to the small sizes of pits (mare, highland, and impact melt) and the absolute ages of their host materials, it is likely that most pits formed as secondary features.

40 CFR 60.1435 - What is an air curtain incinerator?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Small Municipal... forcefully projecting a curtain of air across an open chamber or open pit in which combustion occurs...

Equipment Selection by using Fuzzy TOPSIS Method

NASA Astrophysics Data System (ADS)

Yavuz, Mahmut

2016-10-01

In this study, Fuzzy TOPSIS method was performed for the selection of open pit truck and the optimal solution of the problem was investigated. Data from Turkish Coal Enterprises was used in the application of the method. This paper explains the Fuzzy TOPSIS approaches with group decision-making application in an open pit coal mine in Turkey. An algorithm of the multi-person multi-criteria decision making with fuzzy set approach was applied an equipment selection problem. It was found that Fuzzy TOPSIS with a group decision making is a method that may help decision-makers in solving different decision-making problems in mining.

Factors influencing habitat selection by arboreal pit vipers.

PubMed

Sawant, Nitin S; Jadhav, Trupti D

2013-01-01

We studied factors influencing habitat selection by two arboreal species of pit viper, namely Trimeresurus malabaricus (Malabar pit viper) and T. gramineus (Bamboo pit viper). The macrohabitat of these species was classified as forest, forest edge, or open habitat. To determine microhabitat selection, a variety of features at every other snake location were measured. Whether or not the animal was found in a tree, the tree species, its height of perch, position on the branch (distal/ apical/middle), diameter of the branch, the tree canopy (thick/sparse) and vegetation of the area (thick/sparse) were recorded. Assessment of habitat was done to determine how patterns of habitat use vary seasonally. Shaded ambient (air) temperatures and humidity were recorded. Data pertaining to 90 individuals of T. malabaricus and 100 individuals of T. gramineus were recorded. Trimeresurus malabaricus selected home ranges that included areas with thick vegetation and were encountered at regions of higher altitude. Neither of the species was found in open habitats. Both of the species preferred diverse habitats and were spread over the entire available space during the monsoon; they did not show any preference for the perch height during different seasons. Males had a positive correlation between body mass and preferred perch diameter. The present study suggests that several factors play an important role in habitat selection by these arboreal pit vipers, thus making them highly habitat-specific.

40 CFR 62.15365 - What is an air curtain incinerator?

Code of Federal Regulations, 2010 CFR

2010-07-01

... incinerator? An air curtain incinerator operates by forcefully projecting a curtain of air across an open chamber or open pit in which combustion occurs. Incinerators of this type can be constructed above or...

40 CFR 60.1910 - What is an air curtain incinerator?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Emission Guidelines and Compliance Times for... incinerator operates by forcefully projecting a curtain of air across an open chamber or open pit in which...

The effects of pitting on fatigue crack nucleation in 7075-T6 aluminum alloy

NASA Technical Reports Server (NTRS)

Ma, LI; Hoeppner, David W.

1994-01-01

A high-strength aluminum alloy, 7075-T6, was studied to quantitatively evaluate chemical pitting effects of its corrosion fatigue life. The study focused on pit nucleation, pit growth, and fatigue crack nucleation. Pitting corrosion fatigue experiments were conducted in 3.5 percent NaCl aqueous solution under constant amplitude sinusoidal loading at two frequencies, 5 and 20 Hz. Smooth and unnotched specimens were used in this investigation. A video recording system was developed to allow in situ observation of the surface changes of the specimens during testing. The results indicated that pitting corrosion considerably reduces the fatigue strength by accelerating fatigue crack nucleation. A metallographic examination was conducted on the specimens to evaluate the nature of corrosion pits. First, the actual shapes of the corrosion pits were evaluated by cross-sectioning the pits. Secondly, the relation between corrosion pits and microstructure was also investigated. Finally, the possibility of another corrosion mechanism that might be involved in pitting was explored in this investigation. The fractography of the tested specimens showed that corner corrosion pits were responsible for fatigue crack nucleation in the material due to the associated stress concentration. The pits exhibited variance of morphology. Fatigue life for the experimental conditions appeared to be strongly dependent on pitting kinetics and the crack nucleation stage.

Analysis of open-pit mines using high-resolution topography from UAV

NASA Astrophysics Data System (ADS)

Chen, Jianping; Li, Ke; Sofia, Giulia; Tarolli, Paolo

2015-04-01

Among the anthropogenic topographic signatures on the Earth, open-pit mines deserve a great importance, since they significantly affect the Earth's surface and its related processes (e.g. erosion, pollution). Their geomorphological analysis, therefore, represents a real challenge for the Earth science community. The purpose of this research is to characterize the open-pit mining features using a recently published landscape metric, the Slope Local Length of Auto-Correlation (SLLAC) (Sofia et al., 2014), and high-resolution DEMs (Digital Elevation Models) derived from drone surveyed topography. The research focuses on two main case studies of iron mines located in the Beijing district (P.R. China). The main topographic information (Digital Surface Models, DSMs) was derived using Unmanned Aerial Vehicle (UAV) and the Structure from Motion (SfM) photogrammetric technique. The results underline the effectiveness of the adopted methodologies and survey techniques in the characterization of the main geomorphic features of the mines. Thanks to the SLLAC, the terraced area given by multi-benched sideways-moving method for the iron extraction is automatically depicted, and using some SLLAC derived parameters, the related terraces extent is automatically estimated. The analysis of the correlation length orientation, furthermore, allows to identify the terraces orientation respect to the North, and to understand as well the shape of the open-pit area. This provides a basis for a large scale and low cost topographic survey for a sustainable environmental planning and, for example, for the mitigation of environmental anthropogenic impact due to mining. References Sofia G., Marinello F, Tarolli P. 2014. A new landscape metric for the identification of terraced sites: the Slope Local Length of Auto-Correlation (SLLAC). ISPRS Journal of Photogrammetry and Remote Sensing, doi:10.1016/j.isprsjprs.2014.06.018

Op-Ug TD Optimizer Tool Based on Matlab Code to Find Transition Depth From Open Pit to Block Caving / Narzędzie Optymalizacyjne Oparte O Kod Matlab Wykorzystane Do Określania Głębokości Przejściowej Od Wydobycia Odkrywkowego Do Wybierania Komorami

NASA Astrophysics Data System (ADS)

Bakhtavar, E.

2015-09-01

In this study, transition from open pit to block caving has been considered as a challenging problem. For this purpose, the linear integer programing code of Matlab was initially developed on the basis of the binary integer model proposed by Bakhtavar et al (2012). Then a program based on graphical user interface (GUI) was set up and named "Op-Ug TD Optimizer". It is a beneficial tool for simple application of the model in all situations where open pit is considered together with block caving method for mining an ore deposit. Finally, Op-Ug TD Optimizer has been explained step by step through solving the transition from open pit to block caving problem of a case ore deposit. W pracy tej rozważano skomplikowane zagadnienie przejścia od wybierania odkrywkowego do komorowego. W tym celu opracowano kod programowania liniowego w środowisku MATLAB w oparciu o model liczb binarnych zaproponowany przez Bakhtavara (2012). Następnie opracowano program z wykorzystujący graficzny interfejs użytkownika o nazwie Optymalizator Op-Ug TD. Jest to niezwykle cenne narzędzie umożliwiające stosowanie modelu dla wszystkich warunków w sytuacjach gdy rozważamy prowadzenie wydobycia metodą odkrywkową oraz wydobycie komorowe przy eksploatacji złóż rud żelaza. W końcowej części pracy podano szczegółową instrukcję stosowanie programu Optymalizator na przedstawionym przykładzie przejścia od wydobycia rud żelaza metodami odkrywkowymi poprzez wydobycie komorami.

Fishery resource utilization of a restored estuarine borrow pit: a beneficial use of dredged material case study.

PubMed

Reine, Kevin; Clarke, Douglas; Ray, Gary; Dickerson, Charles

2013-08-15

Numerous pits in coastal waters are subject to degraded water quality and benthic habitat conditions, resulting in degraded fish habitat. A pit in Barnegat Bay, New Jersey (USA) was partially filled with dredged sediment to increase flushing, alleviate hypoxia, and enhance benthic assemblages. Restoration objectives were assessed in terms of benthic community parameters and fishery resource occupation. Restoration resulted in increased benthic diversity (bottom samples) and the absence of water column stratification. Fisheries resources occupied the entire water column, unlike pre-restoration conditions where finfish tended to avoid the lower water column. The partial restoration option effectively reproduced an existing borrow pit configuration (Hole #5, control), by decreasing total depth from -11 m to -5.5 m, thereby creating a habitat less susceptible to hypoxic/anoxic conditions, while retaining sufficient vertical relief to maintain associations with juvenile weakfish and other forage fishes. Partially filling pits using dredged material represents a viable restoration alternative. Published by Elsevier Ltd.

A comparison of conventional capture versus PIT reader techniques for estimating survival and capture probabilities of big brown bats (Eptesicus fuscus)

USGS Publications Warehouse

Ellison, L.E.; O'Shea, T.J.; Neubaum, D.J.; Neubaum, M.A.; Pearce, R.D.; Bowen, R.A.

2007-01-01

We compared conventional capture (primarily mist nets and harp traps) and passive integrated transponder (PIT) tagging techniques for estimating capture and survival probabilities of big brown bats (Eptesicus fuscus) roosting in buildings in Fort Collins, Colorado. A total of 987 female adult and juvenile bats were captured and marked by subdermal injection of PIT tags during the summers of 2001-2005 at five maternity colonies in buildings. Openings to roosts were equipped with PIT hoop-style readers, and exit and entry of bats were passively monitored on a daily basis throughout the summers of 2002-2005. PIT readers 'recaptured' adult and juvenile females more often than conventional capture events at each roost. Estimates of annual capture probabilities for all five colonies were on average twice as high when estimated from PIT reader data (P?? = 0.93-1.00) than when derived from conventional techniques (P?? = 0.26-0.66), and as a consequence annual survival estimates were more precisely estimated when using PIT reader encounters. Short-term, daily capture estimates were also higher using PIT readers than conventional captures. We discuss the advantages and limitations of using PIT tags and passive encounters with hoop readers vs. conventional capture techniques for estimating these vital parameters in big brown bats. ?? Museum and Institute of Zoology PAS.

Advantages and limitations for users of double pit pour-flush latrines: a qualitative study in rural Bangladesh.

PubMed

Hussain, Faruqe; Clasen, Thomas; Akter, Shahinoor; Bawel, Victoria; Luby, Stephen P; Leontsini, Elli; Unicomb, Leanne; Barua, Milan Kanti; Thomas, Brittany; Winch, Peter J

2017-05-25

In rural Bangladesh, India and elsewhere, pour-flush pit latrines are the most common sanitation system. When a single pit latrine becomes full, users must empty it themselves and risk exposure to fresh feces, pay an emptying service to remove pit contents or build a new latrine. Double pit pour-flush latrines may serve as a long-term sanitation option including high water table areas because the pits do not need to be emptied immediately and the excreta decomposes into reusable soil. Double pit pour-flush latrines were implemented in rural Bangladesh for 'hardcore poor' households by a national NGO, BRAC. We conducted interviews, focus groups, and spot checks in two low-income, rural areas of Bangladesh to explore the advantages and limitations of using double pit latrines compared to single pit latrines. The rural households accepted the double pit pour-flush latrine model and considered it feasible to use and maintain. This latrine design increased accessibility of a sanitation facility for these low-income residents and provided privacy, convenience and comfort, compared to open defecation. Although a double pit latrine is more costly and requires more space than a single pit latrine the households perceived this sanitation system to save resources, because households did not need to hire service workers to empty pits or remove decomposed contents themselves. In addition, the excreta decomposition process produced a reusable soil product that some households used in homestead gardening. The durability of the latrine superstructures was a problem, as most of the bamboo-pole superstructure broke after 6-18 months of use. Double pit pour-flush latrines are a long-term improved sanitation option that offers users several important advantages over single pit pour-flush latrines like in rural Bangladesh which can also be used in areas with high water table. Further research can provide an understanding of the comparative health impacts and effectiveness of the model in preventing human excreta from entering the environment.

Derivation and Validation of a Material Model for Clayey Sand for Use in Landmine Detonation Computational Analyses

DTIC Science & Technology

2008-01-01

pit floor is built using a commercial swimming pool liner. Once the pit liners are in place, a series of water hoses is placed in pit bottom to...Belvoir RDEC, 1993. [9]. D. Bergeron, S. Hlady and M. P. Braid , 17th International MABS Symposium, 2002. [10]. M. Grujicic, B. Pandurangan and B

Millennium Open Pit Mine, Alberta, Canada

NASA Technical Reports Server (NTRS)

2007-01-01

Near Fort McMurray, Alberta, Canada, on the east bank of the Athabasca River, are found the Steepbank and Millennium mines. These open pit mines produce oil sands that are processed to recover bitumen, and then upgrade it to refinery-ready raw crude oil, and diesel fuel.

The ASTER images were acquired September 22, 2000 and July 31, 2007, cover an area of 22.5 x 25.5 km, and are located near 57 degrees north latitude, 111.5 degrees west longitude.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

Slope Stability Analysis of Waste Dump in Sandstone Open Pit Osielec

NASA Astrophysics Data System (ADS)

Adamczyk, Justyna; Cała, Marek; Flisiak, Jerzy; Kolano, Malwina; Kowalski, Michał

2013-03-01

This paper presents the slope stability analysis for the current as well as projected (final) geometry of waste dump Sandstone Open Pit "Osielec". For the stability analysis six sections were selected. Then, the final geometry of the waste dump was designed and the stability analysis was conducted. On the basis of the analysis results the opportunities to improve the stability of the object were identified. The next issue addressed in the paper was to determine the proportion of the mixture containing mining and processing wastes, for which the waste dump remains stable. Stability calculations were carried out using Janbu method, which belongs to the limit equilibrium methods.

Open-pit coal mine production sequencing incorporating grade blending and stockpiling options: An application from an Indian mine

NASA Astrophysics Data System (ADS)

Kumar, Ashish; Chatterjee, Snehamoy

2017-05-01

Production scheduling is a crucial aspect of the mining industry. An optimal and efficient production schedule can increase the profits manifold and reduce the amount of waste to be handled. Production scheduling for coal mines is necessary to maintain consistency in the quality and quantity parameters of coal supplied to power plants. Irregularity in the quality parameters of the coal can lead to heavy losses in coal-fired power plants. Moreover, the stockpiling of coal poses environmental and fire problems owing to low incubation periods. This article proposes a production scheduling formulation for open-pit coal mines including stockpiling and blending opportunities, which play a major role in maintaining the quality and quantity of supplied coal. The proposed formulation was applied to a large open-pit coal mine in India. This contribution provides an efficient production scheduling formulation for coal mines after utilizing the stockpile coal within the incubation periods with the maximization of discounted cash flows. At the same time, consistency is maintained in the quality and quantity of coal to power plants through blending and stockpiling options to ensure smooth functioning.

The Three-Dimensional (3D) Numerical Stability Analysis of Hyttemalmen Open-Pit

NASA Astrophysics Data System (ADS)

Cała, Marek; Kowalski, Michał; Stopkowicz, Agnieszka

2014-10-01

The purpose of this paper was to perform the 3D numerical calculations allowing slope stability analysis of Hyttemalmen open pit (location Kirkenes, Finnmark Province, Norway). After a ramp rock slide, which took place in December 2010, as well as some other small-scale rock slope stability problems, it proved necessary to perform a serious stability analyses. The Hyttemalmen open pit was designed with a depth up to 100 m, a bench height of 24 m and a ramp width of 10 m. The rock formation in the iron mining district of Kirkenes is called the Bjornevaten Group. This is the most structurally complicated area connected with tectonic process such as folding, faults and metamorphosis. The Bjornevaten Group is a volcano-sedimentary sequence. Rock slope stability depends on the mechanical properties of the rock, hydro-geological conditions, slope topography, joint set systems and seismic activity. However, rock slope stability is mainly connected with joint sets. Joints, or general discontinuities, are regarded as weak planes within rock which have strength reducing consequences with regard to rock strength. Discontinuities within the rock mass lead to very low tensile strength. Several simulations were performed utilising the RocLab (2007) software to estimate the gneiss cohesion for slopes of different height. The RocLab code is dedicated to estimate rock mass strength using the Hoek-Brown failure criterion. Utilising both the GSI index and the Hoek-Brown strength criterion the equivalent Mohr-Coulomb parameters (cohesion and angle of internal friction) can be calculated. The results of 3D numerical calculations (with FLA3D code) show that it is necessary to redesign the slope-bench system in the Hyttemalmen open pit. Changing slope inclination for lower stages is recommended. The minimum factor of safety should be equal 1.3. At the final planned stage of excavation, the factor of safety drops to 1.06 with failure surface ranging through all of the slopes. In the case of a slope angle 70° for lower stages, FS = 1.26, which is not enough to provide slope stability. Another series of calculations were therefore performed taking water table lowering into consideration, which increases the global safety factor. It was finally evaluated, that for a water table level of 72 m the factor of safety equals 1.3, which is enough to assure global open-pit stability.

Simple Techniques For Assessing Impacts Of Oil And Gas Operations On Federal Lands - A Field Evaluation At Big South Fork National River And Recreation Area, Scott County, Tennessee

USGS Publications Warehouse

Otton, James K.; Zielinski, Robert A.

2000-01-01

Simple, cost-effective techniques are needed for land managers to assess the environmental impacts of oil and gas production activities on public lands so that sites may be prioritized for further, more formal assessment or remediation. These techniques should allow the field investigator to extend the assessment beyond the surface disturbances documented by simple observation and mapping using field-portable instruments and expendable materials that provide real-time data. The principal contaminants of current concern are hydrocarbons, produced water, and naturally occurring radioactive materials (NORM). Field investigators can examine sites for the impacts of hydrocarbon releases using a photoionization detector (PID) and a soil auger. Volatile organic carbon (VOC) in soil gases in an open auger hole or in the head space of a bagged and gently warmed auger soil sample can be measured by the PID. This allows detection of hydrocarbon movement in the shallow subsurface away from areas of obvious oil-stained soils or oil in pits at a production site. Similarly, a field conductivity meter and chloride titration strips can be used to measure salts in water and soil samples at distances well beyond areas of surface salt scarring. Use of a soil auger allows detection of saline subsoils in areas where salts may be flushed from the surface soil layers. Finally, a microRmeter detects the presence of naturally occurring radioactive materials (NORM) in equipment and soils. NORM often goes undetected at many sites although regulations limiting NORM in equipment and soils are being promulgated in several States and are being considered by the USEPA. With each technique, background sampling should be done for comparison with impacted areas. The authors examined sites in the Big South Fork National River and Recreation Area in November of 1999. A pit at one site at the edge of the flood plain of a small stream had received crude oil releases from a nearby tank. Auger holes down gradient from the pit showed the presence of anomalous concentrations of VOCs at depths of 3 feet for a distance of about 50 feet. PID readings at other sites showed 1) one reclaimed site where hydrocarbon biodegradation was incomplete; 2) one reclaimed site where biodegradation had left no traces of VOCS; and 3) two sites where traces of substantial offsite migration of hydrocarbons occurred. Produced water salts at one site have migrated many 100s of feet downvalley from the area of salt scarring and tree death adjacent to the pits. Naturally occurring radioactivity (NORM) at most sites was at background. One site showed anomalous radioactivity related to NORM in a small brine pit. Some of this NORM has moved downslope from the outlet pipe to the pit.

GEOCHEMICAL EVOLUTION OF GROUND WATER AND TRANSPORT OF MERCURY AT THE SULPHUR BANK MERCURY MINE SUPERFUND SITE IN NORTHERN CALIFORNIA, USA

EPA Science Inventory

The Sulphur Bank Mercury Mine, located on the shore of Clear Lake, Lake County, California, is a potential source for a modern-day mercury flux into the local aquatic ecosystem. Surface mining created the Herman Pit, a 9.3 ha open pit with a depth > 30 m, while overburden and pr...

76 FR 60474 - Intent To Prepare a Draft Environmental Impact Statement (DEIS) for the Haile Gold Mine in...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-29

...--County on January 28, 2011. The public notice is available on Charleston District's public Web site at... eight open mining pits over a twelve-year period, with pit depths ranging from 110 to 840 feet deep. The... of January 28, 2011, and are available on Charleston District's public Web site at http://www.sac...

Low-power, ultrafast, and dynamic all-optical tunable plasmon induced transparency in two stub resonators side-coupled with a plasmonic waveguide system

NASA Astrophysics Data System (ADS)

Wang, Boyun; Zeng, Qingdong; Xiao, Shuyuan; Xu, Chen; Xiong, Liangbin; Lv, Hao; Du, Jun; Yu, Huaqing

2017-11-01

We theoretically and numerically investigate a low-power, ultrafast, and dynamic all-optical tunable plasmon induced transparency (PIT) in two stub resonators side-coupled with a metal-dielectric-metal (MDM) plasmonic waveguide system. The optical Kerr effect is enhanced by the local electromagnetic field of surface plasmon polaritons (SPPs) and the plasmonic waveguide based on graphene-Ag composite material structures with large effective Kerr nonlinear coefficient. An ultrafast response time of the order of 1 ps is reached because of ultrafast carrier relaxation dynamics of graphene. With dynamically tuning the propagation phase of the plasmonic waveguide, π-phase shift of the transmission spectrum in the PIT system is achieved under excitation of a pump light with an intensity as low as 5.8 MW cm-2. The group delay is controlled between 0.14 and 0.67 ps. Moreover, the tunable bandwidth of about 42 nm is obtained. For the indirect coupling between two stub cavities or the phase coupling scheme, the phase shift multiplication effect of the PIT effect is found. All observed schemes are analyzed rigorously through finite-difference time-domain simulations and coupled-mode formalism. This work not only paves the way towards the realization of on-chip integrated nanophotonic devices but also opens the possibility of the construction of ultrahigh-speed information processing chips based on plasmonic circuits.

Pit formation observed in a multilayer dielectric coating as a result of simulated space environmental exposure

NASA Astrophysics Data System (ADS)

Fuqua, Peter D.; Presser, Nathan; Barrie, James D.; Meshishnek, Michael J.; Coleman, Dianne J.

2002-06-01

Certain spaceborne telescope designs require that dielectric-coated lenses be exposed to the energetic electrons and protons associated with the space environment. Test coupons that were exposed to a simulated space environment showed extensive pitting as a result of dielectric breakdown. A typical pit was 50-100 mum at the surface and extended to the substrate material, in which a 10-mum-diameter melt region was found. Pitting was not observed on similar samples that had also been overcoated with a transparent conductive thin film. Measurement of the bidirectional reflectance distribution transfer function showed that pitting caused a fivefold to tenfold increase in the scattering of visible light.

Molten salt corrosion of SiC: Pitting mechanism

NASA Technical Reports Server (NTRS)

Jacobson, N. S.; Smialek, J. L.

1985-01-01

Thin films of Na2SO4 and Na2CO3 at 1000 C lead to severe pitting of sintered alpha-SiC. These pits are important as they cause a strength reduction in this material. The growth of product layers is related to pit formation for the Na2CO3 case. The early reaction stages involve repeated oxidation and dissolution to form sodium silicate. This results in severe grain boundary attack. After this a porous silica layer forms between the sodium silicate melt and the SiC. The pores in this layer appear to act as paths for the melt to reach the SiC and create larger pits.

Earth Observations taken by the Expedition 16 Crew

NASA Image and Video Library

2008-03-05

ISS016-E-031056 (3 March 2008) --- Cananea Copper Mine, Sonora, Mexico is featured in this image photographed by an Expedition 16 crewmember on the International Space Station. One of the largest open-pit copper mines in the world, the Cananea mine produced over 164,000 tons of copper in 2006. The mine is located approximately 40 kilometers south of the border between the USA (Arizona) and Mexico (Sonora). Copper and gold ores at Cananea are found in a porphyry copper deposit, a geological structure formed by crystal-rich magma moving upwards through pre-existing rock layers. A porphyry - an igneous rock with large crystals in a fine-grained matrix -- is formed as the magma cools and crystallizes. While crystallization is occurring, hot fluids can circulate through the magma and surrounding rocks via fractures. This hydrothermal alteration of the rocks typically forms copper-bearing and other minerals. Much of the Cananea mine's ore is concentrated in breccia pipes -- mineralized rod or chimney-shaped bodies that contain broken rock fragments. The active, two-kilometers-in-diameter Colorada Pit (top right) is recognizable in this image by the concentric steps or benches cut around its perimeter. These benches allow for access into the pit for extraction of ore and waste materials. Water (black) is visible filling the bottom of the pit, and several other basins in the surrounding area. The city of Cananea -- marked by its street grid -- is located to the northeast of the mine workings. A leachate reservoir is located to the east of the mine (lower left) for removal and evaporation of water pumped from the mine workings -- the bluish-white coloration of deposits near the reservoir suggests the high mineral content of the leachate. A worker strike halted mine operations in 2007.

Influence of Postbuild Microstructure on the Electrochemical Behavior of Additively Manufactured 17-4 PH Stainless Steel

NASA Astrophysics Data System (ADS)

Stoudt, M. R.; Ricker, R. E.; Lass, E. A.; Levine, L. E.

2017-03-01

The additive manufacturing build process produces a segregated microstructure with significant variations in composition and phases that are uncommon in traditional wrought materials. As such, the relationship between the postbuild microstructure and the corrosion resistance is not well understood. Stainless steel alloy 17-4 precipitation hardened (SS17-4PH) is an industrially relevant alloy for applications requiring high strength and good corrosion resistance. A series of potentiodynamic scans conducted in a deaerated 0.5-mol/L NaCl solution evaluated the influence of these microstructural differences on the pitting behavior of SS17-4. The pitting potentials were found to be higher in the samples of additively processed material than in the samples of the alloy in wrought form. This indicates that the additively processed material is more resistant to localized corrosion and pitting in this environment than is the wrought alloy. The results also suggest that after homogenization, the additively produced SS17-4 could be more resistant to pitting than the wrought SS17-4 is in an actual service environment.

The Influence of Post-Build Microstructure on the Electrochemical Behavior of Additively Manufactured 17-4 PH Stainless Steel.

PubMed

Stoudt, M R; Ricker, R E; Lass, E A; Levine, L E

2017-03-01

The additive manufacturing (AM) build process produces a segregated microstructure with significant variations in composition and phases that are uncommon in traditional wrought materials. As such, the relationship between the post-build microstructure and the corrosion resistance is not well understood. Stainless steel alloy 17-4PH is an industrially-relevant alloy for applications requiring high-strength and good corrosion resistance. A series of potentiodynamic scans conducted in a deaerated 0.5 mol/L NaCl solution evaluated the influence of these microstructural differences on the pitting behavior of SS17-4. The pitting potentials were found to be higher in the samples of additively-processed material than in samples of the alloy in wrought form. This indicates that the additively-processed material is more resistant to localized corrosion and pitting in this environment than the wrought alloy. The results also suggest that after homogenization, the additively-produced SS17-4 could be more resistant to pitting than wrought SS17-4 in an actual service environment.

The Influence of Post-Build Microstructure on the Electrochemical Behavior of Additively Manufactured 17-4 PH Stainless Steel

PubMed Central

Stoudt, M. R.; Ricker, R. E.; Lass, E. A.; Levine, L. E.

2017-01-01

The additive manufacturing (AM) build process produces a segregated microstructure with significant variations in composition and phases that are uncommon in traditional wrought materials. As such, the relationship between the post-build microstructure and the corrosion resistance is not well understood. Stainless steel alloy 17-4PH is an industrially-relevant alloy for applications requiring high-strength and good corrosion resistance. A series of potentiodynamic scans conducted in a deaerated 0.5 mol/L NaCl solution evaluated the influence of these microstructural differences on the pitting behavior of SS17-4. The pitting potentials were found to be higher in the samples of additively-processed material than in samples of the alloy in wrought form. This indicates that the additively-processed material is more resistant to localized corrosion and pitting in this environment than the wrought alloy. The results also suggest that after homogenization, the additively-produced SS17-4 could be more resistant to pitting than wrought SS17-4 in an actual service environment. PMID:28757787

Cloning of the canine gene encoding transcription factor Pit-1 and its exclusion as candidate gene in a canine model of pituitary dwarfism.

PubMed

Lantinga-van Leeuwen, I S; Mol, J A; Kooistra, H S; Rijnberk, A; Breen, M; Renier, C; van Oost, B A

2000-01-01

Combined pituitary hormone deficiency (CPHD) is an autosomal recessive inherited disease of German shepherd dogs characterized primarily by dwarfism. In mice and humans a similar genetic disorder has been described that results from an alteration in the gene encoding the transcription factor Pit-1. In this study we characterized the canine Pit-1 gene, determined the chromosomal localization of the Pit-1 gene, and screened dwarf German shepherd dogs for the presence of mutations in this gene. The full-length canine Pit-1 cDNA contained an open reading frame encoding 291 amino acids, 92 bp of 5'-untranslated region, and 1959 bp of 3'-untranslated region. The deduced amino acid sequence was highly homologous with Pit-1 of other mammalian species. Using a Pit-1 BAC clone as probe, the Pit-1 gene was mapped by FISH to canine Chromosome (Chr) 31. In dwarf German shepherd dogs a C to A transversion was detected, causing a Phe (TTC) to Leu (TTA) substitution at codon 81. This alteration was present neither in other canine breeds analyzed nor in other mammalian species. However, healthy German shepherd dogs were also homozygous for the mutant allele, indicating that it is not the primary disease-causing mutation. In addition, linkage analysis of polymorphic DNA markers flanking the Pit-1 gene, 41K19 and 52L05, revealed no co-segregation between the Pit-1 locus and the CPHD phenotype. These findings suggest that a gene other than Pit-1 is responsible for the pituitary anomaly in dwarf German shepherd dogs.

Expression of ayu (Plecoglossus altivelis) Pit-1 in Escherichia coli: its purification and immunohistochemical detection using monoclonal antibody.

PubMed

Chiu, Chi-Chien; John, Joseph Abraham Christopher; Hseu, Tzong-Hsiung; Chang, Chi-Yao

2002-03-01

The pituitary-specific transcription factor Pit-1 belongs to the family of POU-domain proteins and is known to play an important role in the differentiation of pituitary cells. Here we report the complete nucleotide sequence of cDNA encoding Pit-1 from the brackish water fish, ayu (Plecoglossus altivelis). Nucleotide sequence analysis of 1910 bp of ayu Pit-1 cDNA revealed an open reading frame of 1074 bp that encodes a protein of 358 amino acids containing a POU-specific domain, POU homeodomain, and an STA (Ser/Thr-rich activation) transactivation domain. We inserted the coding region of Pit-1 cDNA, obtained by PCR, into a pET-20b(+) plasmid to produce recombinant Pit-1 in Escherichia coli BL21 (DE3) pLysS cells. Upon induction with isopropyl beta-D-thiogalactopyranoside, Pit-1 was expressed and accumulated as inclusion bodies in E. coli. The protein was then purified in one step by affinity chromatography on a nickel-nitrilotriacetic acid agarose column under denaturing conditions. This method yielded 0.7 mg of highly pure and stable protein per 200 ml of bacterial culture. A band of 40 kDa, resolved as recombinant ayu Pit-1 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, agrees well with the molecular mass calculated from the translated cDNA sequence. The purified recombinant Pit-1 was confirmed in vitro through Western blot analysis, using its monoclonal antibody. This monoclonal antibody detected Pit-1 in the nuclei of ayu developing pituitary by immunohistochemical reaction. It serves as a good reagent for the detection of ayu Pit-1 in situ. Copyright 2002 Elsevier Science (USA).

Parturition Pit: The Bony Imprint of Vaginal Birth

PubMed Central

Meyer, Isuzu; Jackson, Bradford; Pitt, Michael J.; Larrison, Matthew C.

2017-01-01

Purpose To retrospectively evaluate for pits along the dorsum of the pubic body in females and compare the presence/absence of these pits to vaginal birth data. Materials and Methods We retrospectively reviewed females with vaginal birth data who underwent pelvic CT. The presence of pits along the dorsum of the pubic body, pit grade (0 = not present; 1 = faintly imperceptible; 2 = present; 3 = prominent), and the presence of osteitis condensans ilii, preauricular sulcus, and sacroiliac joint vacuum phenomenon were assessed on imaging. Musculoskeletal radiologists who were blinded to the birth data evaluated the CTs. 48 males were also evaluated for the presence of pits. Results 482 female patients underwent CT pelvis and 171 were excluded due to lack of vaginal birth data. Of the 311 study patients, 262 had prior vaginal birth(s) and 194 had pits on CT. Only 7 of the 49 patients without prior vaginal birth had pits. There was a statistically significant association between vaginal birth and presence of pits (p<0.0001). Patients with more prominent pits (grades 2/3) had a greater number of vaginal births. As vaginal deliveries increased, the odds of having parturition pits greatly increased, adjusting for age and race at CT (p<0.0001). No males had pits. Conclusion Our study indicates that parturition pits are associated prior vaginal birth and should be considered a characteristic of the female pelvis. The lytic appearance of prominent pits on imaging can simulate disease and create a diagnostic dilemma for interpreting radiologists. PMID:27270921

Survey of nine surface mines in North America. [Nine different mines in USA and Canada

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

Hayes, L.G.; Brackett, R.D.; Floyd, F.D.

This report presents the information gathered by three mining engineers in a 1980 survey of nine surface mines in the United States and Canada. The mines visited included seven coal mines, one copper mine, and one tar sands mine selected as representative of present state of the art in open pit, strip, and terrace pit mining. The purpose of the survey was to investigate mining methods, equipment requirements, operating costs, reclamation procedures and costs, and other aspects of current surface mining practices in order to acquire basic data for a study comparing conventional and terrace pit mining methods, particularly inmore » deeper overburdens. The survey was conducted as part of a project under DOE Contract No. DE-AC01-79ET10023 titled The Development of Optimal Terrace Pit Coal Mining Systems.« less

Pit chains on Enceladus signal the recent tectonic dissection of the ancient cratered terrains

NASA Astrophysics Data System (ADS)

Martin, Emily S.; Kattenhorn, Simon A.; Collins, Geoffrey C.; Michaud, Robert L.; Pappalardo, Robert T.; Wyrick, Danielle Y.

2017-09-01

Enceladus is the first outer solar system body on which pit chains have been positively identified. We map the global distribution of pit chains and show that pit chains are among the youngest tectonic features on Enceladus's surface, concentrated in the cratered plains centered on Enceladus's Saturnian and anti-Saturnian hemispheres. Pit chains on Enceladus are interpreted as the surface expressions of subsurface dilational fractures underlying a cover of unconsolidated material, which we infer to be a geologically young cover of loose regolith that mantles the surface of Enceladus. A widespread layer of regolith may act to insulate the surface, which has implications for the thermal state of Enceladus's ice shell. The widespread distribution of pit chains across the cratered plains indicates that this ancient surface has recently been tectonically active.

Characterization of HgCdTe and Related Materials For Third Generation Infrared Detectors

NASA Astrophysics Data System (ADS)

Vaghayenegar, Majid

Hg1-xCdxTe (MCT) has historically been the primary material used for infrared detectors. Recently, alternative substrates for MCT growth such as Si, as well as alternative infrared materials such as Hg1-xCdxSe, have been explored. This dissertation involves characterization of Hg-based infrared materials for third generation infrared detectors using a wide range of transmission electron microscopy (TEM) techniques. A microstructural study on HgCdTe/CdTe heterostructures grown by MBE on Si (211) substrates showed a thin ZnTe layer grown between CdTe and Si to mediate the large lattice mismatch of 19.5%. Observations showed large dislocation densities at the CdTe/ZnTe/Si (211) interfaces, which dropped off rapidly away from the interface. Growth of a thin HgTe buffer layer between HgCdTe and CdTe layers seemed to improve the HgCdTe layer quality by blocking some defects. A second study investigated the correlation of etch pits and dislocations in as-grown and thermal-cycle-annealed (TCA) HgCdTe (211) films. For as-grown samples, pits with triangular and fish-eye shapes were associated with Frank partial and perfect dislocations, respectively. Skew pits were determined to have a more complex nature. TCA reduced the etch-pit density by 72%. Although TCA processing eliminated the fish-eye pits, dislocations reappeared in shorter segments in the TCA samples. Large pits were observed in both as-grown and TCA samples, but the nature of any defects associated with these pits in the as-grown samples is unclear. Microstructural studies of HgCdSe revealed large dislocation density at ZnTe/Si(211) interfaces, which dropped off markedly with ZnTe thickness. Atomic-resolution STEM images showed that the large lattice mismatch at the ZnTe/Si interface was accommodated through {111}-type stacking faults. A detailed analysis showed that the stacking faults were inclined at angles of 19.5 and 90 degrees at both ZnTe/Si and HgCdSe/ZnTe interfaces. These stacking faults were associated with Shockley and Frank partial dislocations, respectively. Initial attempts to delineate individual dislocations by chemical etching revealed that while the etchants successfully attacked defective areas, many defects in close proximity to the pits were unaffected.

Characterization of Emissions from Open Burning of Meals ...

EPA Pesticide Factsheets

Emissions from burning current and candidate Meals Ready-to-Eat (MRE) packaging and shipping containers were characterized in an effort to assuage concerns that combustive disposal of waste at forward operating bases could pose an environmental or inhalation threat. Four types of container materials, both box and liners, including the currently used fiberboard, new corrugated fiberboard with Spektrakote polymer, new fiberboard without Spektrakote polymer, and the current fiberboard without wet strength were burned in an open burn test facility that simulated the burn pit disposal methods in Iraq and Afghanistan. MREs, including both current and proposed packaging materials, were added to a single container type to examine their effect on emissions. One quarter of the food was left in the packaging to represent unused meal components. The proposed packaging, consisting of a nano-composite polymer, was added in 25 % increments compared to traditional MRE packaging to create a range of usage levels. Emission factors, mass of pollutant per mass of burned material, were increased over the emission factors of the package containers themselves by the addition of the multi-component MREs, with the exception of Volatile Organic Compounds (VOCs). In general, little distinction was observed when comparing emission factors from the four container materials and when comparing the four MRE compositions. The majority of Particulate Matter (PM) emissions were of particles that

EXTERIOR OVERVIEW, LOOKING NORTH, OF THIS 400' DEEP LIMESTONE QUARRY ...

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

EXTERIOR OVERVIEW, LOOKING NORTH, OF THIS 400' DEEP LIMESTONE QUARRY PIT ('THE OLD PIT') WITH LEDGE PREPARED FOR LIMESTONE EXTRACTION. AN ELEVEN-HOLE SHOT WILL DISLODGE APPROXIMATELY 25,000 TONS OF LIMESTONE WHICH, AFTER LOADING AND CRUSHING, WILL BE USED FOR ROAD CONSTRUCTION. THE CALERA QUARRY IS ONE OF FOUR ACTIVE VULCAN MATERIALS COMPANY QUARRIES IN THE DISTRICT. VULCAN MATERIALS, A FORTUNE 500 FIRM, ESTABLISHED IN BIRMINGHAM IN 1906 AS BIRMINGHAM SLAG COMPANY, VULCAN MATERIALS IS THE NATION'S FOREMOST PRODUCER OF CONSTRUCTION AGGREGATE AND A LEADING CHEMICALS MANUFACTURER. - Vulcan Material Company, Calera Quarry, 1614 Highway 84, Calera, Shelby County, AL

EXTERIOR OVERVIEW, LOOKING NORTH, OF THIS 400' DEEP LIMESTONE QUARRY ...

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

EXTERIOR OVERVIEW, LOOKING NORTH, OF THIS 400' DEEP LIMESTONE QUARRY PIT ("THE OLD PIT") WITH LEDGE PREPARED FOR LIMESTONE EXTRACTION. AN ELEVEN-HOLE SHOT WILL DISLODGE APPROXIMATELY 25,000 TONS OF LIMESTONE WHICH, AFTER LOADING AND CRUSHING, WILL BE USED FOR ROAD CONSTRUCTION. THE CALERA QUARRY IS ONE OF FOUR ACTIVE VULCAN MATERIALS COMPANY QUARRIES IN THE DISTRICT. VULCAN MATERIALS, A FORTUNE 500 FIRM, ESTABLISHED IN BIRMINGHAM IN 1906 AS BIRMINGHAM SLAG COMPANY, VULCAN MATERIALS IS THE NATION'S FOREMOST PRODUCER OF CONSTRUCTION AGGREGATE AND A LEADING CHEMICALS MANUFACTURER - Vulcan Material Company, Calera Quarry, 1614 Highway 84, Calera, Shelby County, AL

Novel approach for extinguishing large-scale coal fires using gas-liquid foams in open pit mines.

PubMed

Lu, Xinxiao; Wang, Deming; Qin, Botao; Tian, Fuchao; Shi, Guangyi; Dong, Shuaijun

2015-12-01

Coal fires are a serious threat to the workers' security and safe production in open pit mines. The coal fire source is hidden and innumerable, and the large-area cavity is prevalent in the coal seam after the coal burned, causing the conventional extinguishment technology difficult to work. Foams are considered as an efficient means of fire extinguishment in these large-scale workplaces. A noble foam preparation method is introduced, and an original design of cavitation jet device is proposed to add foaming agent stably. The jet cavitation occurs when the water flow rate and pressure ratio reach specified values. Through self-building foaming system, the high performance foams are produced and then infused into the blast drilling holes at a large flow. Without complicated operation, this system is found to be very suitable for extinguishing large-scale coal fires. Field application shows that foam generation adopting the proposed key technology makes a good fire extinguishment effect. The temperature reduction using foams is 6-7 times higher than water, and CO concentration is reduced from 9.43 to 0.092‰ in the drilling hole. The coal fires are controlled successfully in open pit mines, ensuring the normal production as well as the security of personnel and equipment.

Geomechanical Assessments of Simultaneous Operation in the Case of Transition from Open Pit to Underground Mine in Vietnam

NASA Astrophysics Data System (ADS)

Niedbalski, Zbigniew; Nguyen, Phu Minh Vuong; Widzyk-Capehart, Eleonora

2018-03-01

Nowadays, for a number of reasons, many open pit mines are considering a transition from Open Pit (OP) to Underground (UG) to remain competitive. In OP-UG transition, UG operation is operated simultaneously with the OP operation for a certain period of time. Guidelines for the simultaneous operation of OP and UG are very difficult to establish, as there are very few case studies available. Yet, because of the OP-UG interactions; the operation has a higher safety, technical and management requirements than the OP or UG methods when considered separately. In Vietnam, Cao Son is one of many OP mines, which decided to change the operational system from OP to UG. Simultaneous operation started in 2015 and will be conducted until 2030 when the OP mine Cao Son ends its mining activities. In this paper, selected geomechanical considerations of the simultaneous operation are presented. A number of numerical modelling calculations using finitedifference software with code FLAC were carried out for calibration process, slope stability analysis and the OP-UG interaction analysis for the Cao Son - Khe Cham II-IV mine. Based on the results obtained from numerical modelling, the geomechanical assessments of simultaneous operation Cao Son - Khe Cham II-IV are discussed in this paper.

Open Pit Mine 3d Mapping by Tls and Digital Photogrammetry: 3d Model Update Thanks to a Slam Based Approach

NASA Astrophysics Data System (ADS)

Vassena, G.; Clerici, A.

2018-05-01

The state of the art of 3D surveying technologies, if correctly applied, allows to obtain 3D coloured models of large open pit mines using different technologies as terrestrial laser scanner (TLS), with images, combined with UAV based digital photogrammetry. GNSS and/or total station are also currently used to geo reference the model. The University of Brescia has been realised a project to map in 3D an open pit mine located in Botticino, a famous location of marble extraction close to Brescia in North Italy. Terrestrial Laser Scanner 3D point clouds combined with RGB images and digital photogrammetry from UAV have been used to map a large part of the cave. By rigorous and well know procedures a 3D point cloud and mesh model have been obtained using an easy and rigorous approach. After the description of the combined mapping process, the paper describes the innovative process proposed for the daily/weekly update of the model itself. To realize this task a SLAM technology approach is described, using an innovative approach based on an innovative instrument capable to run an automatic localization process and real time on the field change detection analysis.

Geochemical Trends and Natural Attenuation of RDX, Nitrate, and Perchlorate in the Hazardous Test Area Fractured-Granite Aquifer, White Sands Missile Range, New Mexico, 1996-2006

USGS Publications Warehouse

Langman, Jeff B.; Robertson, Andrew J.; Bynum, Jamar; Gebhardt, Fredrick E.

2008-01-01

A fractured-granite aquifer at White Sands Missile Range is contaminated with the explosive compound RDX, nitrate, and perchlorate (oxidizer associated with rocket propellant) from the previous use of the Open Burn/Open Detonation site at the Hazardous Test Area. RDX, nitrate, and perchlorate ground-water concentrations were analyzed to examine source characteristics, spatial and temporal variability, and the influence of the natural attenuation processes of dilution and degradation in the Hazardous Test Area fractured-granite aquifer. Two transects of ground-water wells from the existing monitoring-site network - one perpendicular to ground-water flow (transect A-A') and another parallel to ground-water flow (transect B-B') - were selected to examine source characteristics and the spatial and temporal variability of the contaminant concentrations. Ground-water samples collected in 2005 from a larger sampling of monitoring sites than the two transects were analyzed for various tracers including major ions, trace elements, RDX degradates, dissolved gases, water isotopes, nitrate isotopes, and sulfate isotopes to examine the natural attenuation processes of dilution and degradation. Recharge entrains contaminants at the site and transports them downgradient towards the Tularosa Basin floor through a poorly connected fracture system(s). From 1996 to 2006, RDX, nitrate, and perchlorate concentrations in ground water downgradient from the Open Burn/Open Detonation site have been relatively stable. RDX, nitrate, and perchlorate in ground water from wells near the site indicate dispersed contaminant sources in and near the Open Burn/Open Detonation pits. The sources of RDX and nitrate in the pit area have shifted with time, and the shift correlates with the regrading of the south and east berms of each pit in 2002 and 2003 following closure of the site. The largest RDX concentrations were in ground water about 0.1 mile downgradient from the pits, the largest perchlorate concentrations were in ground water about 0.15 mile downgradient from the pits, and the largest nitrate concentrations were in ground water about 0.25 mile down-gradient from the pits. Strong and moderate correlation of water level and the contaminant concentrations near the source areas and low correlation outside and downgradient from the source areas indicates a diminishing of the water level/contaminant relation with downgradient flow. Ground water was not progressively older at all locations downgradient from the Open Burn/Open Detonation site indicating multiple recharge areas. Major ion and strontium concentrations and d2H and d18O values identified similar sources of recharge waters comprising the aquifer except along the basin periphery where recharge water may be influenced by dissolution of mineral assemblages associated with ore deposits that are present along the basin margins. Ground-water ages, dissolved-solids concentrations, and calcium-strontium concentrations indicate limited or partial connectivity between fractures and contributions of uncontaminated recharge water downgradient from the site that dilutes contaminant concentrations. Changes in RDX and nitrate concentration patterns, the presence of methane, changes in carbon dioxide concentrations and d15N and d34S values, and variable reduction-oxidation conditions suggest degradation of contaminants in the downgradient direction. Estimated values of electron potential were assigned to ground water collected in October 2005 from all monitoring sites at the Hazardous Test Area. Moderate to strong reducing conditions were present upgradient from the Open Burn/Open Detonation site, at the site, and at various locations downgradient from the site, but the aquifer contained well-oxygenated water between many of the reducing areas. The spatial variability of reduction-oxidation conditions in the aquifer exemplifies the partial connectivity of the fracture system(s). Dilution of the contaminants i

Cavitation Resistance in Seedless Vascular Plants: The Structure and Function of Interconduit Pit Membranes1[W][OPEN

PubMed Central

Brodersen, Craig; Jansen, Steven; Choat, Brendan; Rico, Christopher; Pittermann, Jarmila

2014-01-01

Plant water transport occurs through interconnected xylem conduits that are separated by partially digested regions in the cell wall known as pit membranes. These structures have a dual function. Their porous construction facilitates water movement between conduits while limiting the spread of air that may enter the conduits and render them dysfunctional during a drought. Pit membranes have been well studied in woody plants, but very little is known about their function in more ancient lineages such as seedless vascular plants. Here, we examine the relationships between conduit air seeding, pit hydraulic resistance, and pit anatomy in 10 species of ferns (pteridophytes) and two lycophytes. Air seeding pressures ranged from 0.8 ± 0.15 MPa (mean ± sd) in the hydric fern Athyrium filix-femina to 4.9 ± 0.94 MPa in Psilotum nudum, an epiphytic species. Notably, a positive correlation was found between conduit pit area and vulnerability to air seeding, suggesting that the rare-pit hypothesis explains air seeding in early-diverging lineages much as it does in many angiosperms. Pit area resistance was variable but averaged 54.6 MPa s m−1 across all surveyed pteridophytes. End walls contributed 52% to the overall transport resistance, similar to the 56% in angiosperm vessels and 64% in conifer tracheids. Taken together, our data imply that, irrespective of phylogenetic placement, selection acted on transport efficiency in seedless vascular plants and woody plants in equal measure by compensating for shorter conduits in tracheid-bearing plants with more permeable pit membranes. PMID:24777347

Gas flow in plant microfluidic networks controlled by capillary valves

NASA Astrophysics Data System (ADS)

Capron, M.; Tordjeman, Ph.; Charru, F.; Badel, E.; Cochard, H.

2014-03-01

The xylem vessels of trees constitute a model natural microfluidic system. In this work, we have studied the mechanism of air flow in the Populus xylem. The vessel microstructure was characterized by optical microscopy, transmission electronic microscopy (TEM), and atomic force microscopy (AFM) at different length scales. The xylem vessels have length ≈15 cm and diameter ≈20μm. Flow from one vessel to the next occurs through ˜102 pits, which are grouped together at the ends of the vessels. The pits contain a thin, porous pit membrane with a thickness of 310 nm. We have measured the Young's moduli of the vessel wall and of the pits (both water-saturated and after drying) by specific nanoindentation and nanoflexion experiments with AFM. We found that both the dried and water-saturated pit membranes have Young's modulus around 0.4 MPa, in agreement with values obtained by micromolding of pits deformed by an applied pressure difference. Air injection experiments reveal that air flows through the xylem vessels when the differential pressure across a sample is larger than a critical value ΔPc=1.8 MPa. In order to model the air flow rate for ΔP ⩾ΔPc, we assumed the pit membrane to be a porous medium that is strained by the applied pressure difference. Water menisci in the pit pores play the role of capillary valves, which open at ΔP =ΔPc. From the point of view of the plant physiology, this work presents a basic understanding of the physics of bordered pits.

In situ nano- to microscopic imaging and growth mechanism of electrochemical dissolution (e.g., corrosion) of a confined metal surface

PubMed Central

Merola, C.; Cheng, H.-W.; Schwenzfeier, K.; Kristiansen, K.; Chen, Y.-J.; Dobbs, H. A.; Valtiner, M.

2017-01-01

Reactivity in confinement is central to a wide range of applications and systems, yet it is notoriously difficult to probe reactions in confined spaces in real time. Using a modified electrochemical surface forces apparatus (EC-SFA) on confined metallic surfaces, we observe in situ nano- to microscale dissolution and pit formation (qualitatively similar to previous observation on nonmetallic surfaces, e.g., silica) in well-defined geometries in environments relevant to corrosion processes. We follow “crevice corrosion” processes in real time in different pH-neutral NaCl solutions and applied surface potentials of nickel (vs. Ag|AgCl electrode in solution) for the mica–nickel confined interface of total area ∼0.03 mm2. The initial corrosion proceeds as self-catalyzed pitting, visualized by the sudden appearance of circular pits with uniform diameters of 6–7 μm and depth ∼2–3 nm. At concentrations above 10 mM NaCl, pitting is initiated at the outer rim of the confined zone, while below 10 mM NaCl, pitting is initiated inside the confined zone. We compare statistical analysis of growth kinetics and shape evolution of individual nanoscale deep pits with estimates from macroscopic experiments to study initial pit growth and propagation. Our data and experimental techniques reveal a mechanism that suggests initial corrosion results in formation of an aggressive interfacial electrolyte that rapidly accelerates pitting, similar to crack initiation and propagation within the confined area. These results support a general mechanism for nanoscale material degradation and dissolution (e.g., crevice corrosion) of polycrystalline nonnoble metals, alloys, and inorganic materials within confined interfaces. PMID:28827338

An InGaN/GaN Superlattice to Enhance the Performance of Green LEDs: Exploring the Role of V-Pits.

PubMed

Liu, Mengling; Zhao, Jie; Zhou, Shengjun; Gao, Yilin; Hu, Jinfeng; Liu, Xingtong; Ding, Xinghuo

2018-06-21

Despite the fact that an InGaN/GaN superlattice (SL) is useful for enhancing the performance of a GaN-based light-emitting diode (LED), its role in improving the efficiency of green LEDs remains an open question. Here, we investigate the influence of a V-pits-embedded InGaN/GaN SL on optical and electrical properties of GaN-based green LEDs. We recorded a sequence of light emission properties of InGaN/GaN multiple quantum wells (MQWs) grown on a 0- and 24-pair InGaN/GaN SL by using scanning electron microscopy (SEM) in combination with a room temperature cathodoluminescence (CL) measurement, which demonstrated the presence of a potential barrier formed by the V-pits around threading dislocations (TDs). We find that an increase in V-pit diameter would lead to the increase of V-pit potential barrier height. Our experimental data suggest that a V-pits-embedded, 24-pair InGaN/GaN SL can effectively suppress the lateral diffusion of carriers into non-recombination centers. As a result, the external quantum efficiency (EQE) of green LEDs is improved by 29.6% at an injection current of 20 mA after implementing the V-pits-embedded InGaN/GaN SL layer. In addition, a lower reverse leakage current was achieved with larger V-pits.

Active Enhancement of Slow Light Based on Plasmon-Induced Transparency with Gain Materials.

PubMed

Zhang, Zhaojian; Yang, Junbo; He, Xin; Han, Yunxin; Zhang, Jingjing; Huang, Jie; Chen, Dingbo; Xu, Siyu

2018-06-03

As a plasmonic analogue of electromagnetically induced transparency (EIT), plasmon-induced transparency (PIT) has drawn more attention due to its potential of realizing on-chip sensing, slow light and nonlinear effect enhancement. However, the performance of a plasmonic system is always limited by the metal ohmic loss. Here, we numerically report a PIT system with gain materials based on plasmonic metal-insulator-metal waveguide. The corresponding phenomenon can be theoretically analyzed by coupled mode theory (CMT). After filling gain material into a disk cavity, the system intrinsic loss can be compensated by external pump beam, and the PIT can be greatly fueled to achieve a dramatic enhancement of slow light performance. Finally, a double-channel enhanced slow light is introduced by adding a second gain disk cavity. This work paves way for a potential new high-performance slow light device, which can have significant applications for high-compact plasmonic circuits and optical communication.

Study of the Rock Mass Failure Process and Mechanisms During the Transformation from Open-Pit to Underground Mining Based on Microseismic Monitoring

NASA Astrophysics Data System (ADS)

Zhao, Yong; Yang, Tianhong; Bohnhoff, Marco; Zhang, Penghai; Yu, Qinglei; Zhou, Jingren; Liu, Feiyue

2018-05-01

To quantitatively understand the failure process and failure mechanism of a rock mass during the transformation from open-pit mining to underground mining, the Shirengou Iron Mine was selected as an engineering project case study. The study area was determined using the rock mass basic quality classification method and the kinematic analysis method. Based on the analysis of the variations in apparent stress and apparent volume over time, the rock mass failure process was analyzed. According to the recent research on the temporal and spatial change of microseismic events in location, energy, apparent stress, and displacement, the migration characteristics of rock mass damage were studied. A hybrid moment tensor inversion method was used to determine the rock mass fracture source mechanisms, the fracture orientations, and fracture scales. The fracture area can be divided into three zones: Zone A, Zone B, and Zone C. A statistical analysis of the orientation information of the fracture planes orientations was carried out, and four dominant fracture planes were obtained. Finally, the slip tendency analysis method was employed, and the unstable fracture planes were obtained. The results show: (1) The microseismic monitoring and hybrid moment tensor analysis can effectively analyze the failure process and failure mechanism of rock mass, (2) during the transformation from open-pit to underground mining, the failure type of rock mass is mainly shear failure and the tensile failure is mostly concentrated in the roof of goafs, and (3) the rock mass of the pit bottom and the upper of goaf No. 18 have the possibility of further damage.

Effect of analysis parameters on non-linear implicit finite element analysis of marine corroded steel plate

NASA Astrophysics Data System (ADS)

Islam, Muhammad Rabiul; Sakib-Ul-Alam, Md.; Nazat, Kazi Kaarima; Hassan, M. Munir

2017-12-01

FEA results greatly depend on analysis parameters. MSC NASTRAN nonlinear implicit analysis code has been used in large deformation finite element analysis of pitted marine SM490A steel rectangular plate. The effect of two types actual pit shape on parameters of integrity of structure has been analyzed. For 3-D modeling, a proposed method for simulation of pitted surface by probabilistic corrosion model has been used. The result has been verified with the empirical formula proposed by finite element analysis of steel surface generated with different pitted data where analyses have been carried out by the code of LS-DYNA 971. In the both solver, an elasto-plastic material has been used where an arbitrary stress versus strain curve can be defined. In the later one, the material model is based on the J2 flow theory with isotropic hardening where a radial return algorithm is used. The comparison shows good agreement between the two results which ensures successful simulation with comparatively less energy and time.

The Edge

NASA Technical Reports Server (NTRS)

2006-01-01

6 April 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the edge (running diagonally from the lower left to the upper right) of a trough, which is part of a large pit crater complex in Noachis Terra. This type of trough forms through the collapse of surface materials into the subsurface, and often begins as a series of individual pit craters. Over time, continued collapse increases the diameter of individual pits until finally, adjacent pits merge to form a trough such as the one captured in this image. The deep shadowed area is caused in part by an overhang; layered rock beneath this overhang is less resistant to erosion, and thus has retreated tens of meters backward, beneath the overhang. A person could walk up inside this 'cave' formed by the overhanging layered material.

Location near: 47.0oS, 355.7oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

Single particle size and fluorescence spectra from emissions of burning materials in a tube furnace to simulate burn pits

NASA Astrophysics Data System (ADS)

Pan, Yong-Le; Houck, Joshua D. T.; Clark, Pamela A.; Pinnick, Ronald G.

2013-08-01

A single-particle fluorescence spectrometer (SPFS) and an aerodynamic particle sizer were used to measure the fluorescence spectra and particle size distribution from the particulate emissions of 12 different burning materials in a tube furnace to simulate open-air burning of garbage. Although the particulate emissions are likely dominated by particles <1 μm diameter, only the spectra of supermicron particles were measured here. The overall fluorescence spectral profiles exhibit either one or two broad bands peaked around 300-450 nm within the 280-650 nm spectral range, when the particles are illuminated with a 263-nm laser. Different burning materials have different profiles, some of them (cigarette, hair, uniform, paper, and plastics) show small changes during the burning process, and while others (beef, bread, carrot, Styrofoam, and wood) show big variations, which initially exhibit a single UV peak (around 310-340 nm) and a long shoulder in visible, and then gradually evolve into a bimodal spectrum with another visible peak (around 430-450 nm) having increasing intensity during the burning process. These spectral profiles could mainly derive from polycyclic aromatic hydrocarbons with the combinations of tyrosine-like, tryptophan-like, and other humic-like substances. About 68 % of these single-particle fluorescence spectra can be grouped into 10 clustered spectral templates that are derived from the spectra of millions of atmospheric aerosol particles observed in three locations; while the others, particularly these bimodal spectra, do not fall into any of the 10 templates. Therefore, the spectra from particulate emissions of burning materials can be easily discriminated from that of common atmospheric aerosol particles. The SFFS technology could be a good tool for monitoring burning pit emissions and possibly for distinguishing them from atmospheric aerosol particles.

Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 13. Mineral Microscopy and Chemistry of Mined and Unmined Porphyry Molybdenum Mineralization Along the Red River, New Mexico: Implications for Ground- and Surface-Water Quality

USGS Publications Warehouse

Plumlee, Geoff; Lowers, Heather; Ludington, Steve; Koenig, Alan; Briggs, Paul

2005-01-01

This report is one in a series presenting results of an interdisciplinary U.S. Geological Survey (USGS) study of ground-water quality in the lower Red River watershed prior to open-pit and underground molybdenite mining at Molycorp's Questa mine. The stretch of the Red River watershed that extends from just upstream of the town of Red River to just above the town of Questa includes several mineralized areas in addition to the one mined by Molycorp. Natural erosion and weathering of pyrite-rich rocks in the mineralized areas has created a series of erosional scars along this stretch of the Red River that contribute acidic waters, as well as mineralized alluvial material and sediments, to the river. The overall goal of the USGS study is to infer the pre-mining ground-water quality at the Molycorp mine site. An integrated geologic, hydrologic, and geochemical model for ground water in the mineralized but unmined Straight Creek drainage is being used as an analogue for the geologic, geochemical, and hydrologic conditions that influenced ground-water quality and quantity at the mine site prior to mining. This report summarizes results of reconnaissance mineralogical and chemical characterization studies of rock samples collected from the various scars and the Molycorp open pit, and of drill cuttings or drill core from bedrock beneath the scars and adjacent debris fans.

An Evaluation of Practical Applicability of Multi-Assortment Production Break-Even Analysis based on Mining Companies

NASA Astrophysics Data System (ADS)

Fuksa, Dariusz; Trzaskuś-Żak, Beata; Gałaś, Zdzisław; Utrata, Arkadiusz

2017-03-01

In the practice of mining companies, the vast majority of them produce more than one product. The analysis of the break-even, which is referred to as CVP (Cost-Volume-Profit) analysis (Wilkinson, 2005; Czopek, 2003) in their case is significantly constricted, given the necessity to include multi-assortment structure in the analysis, which may have more than 20 types of assortments (depending on the grain size) in their offer, as in the case of open-pit mines. The article presents methods of evaluation of break-even (volume and value) for both a single-assortment production and a multi-assortment production. The complexity of problem of break-even evaluation for multi-assortment production has resulted in formation of many methods, and, simultaneously, various approaches to its analysis, especially differences in accounting fixed costs, which may be either totally accounted for among particular assortments, relating to the whole company or partially accounted for among particular assortments and partially relating to the company, as a whole. The evaluation of the chosen methods of break-even analysis, given the availability of data, was based on two examples of mining companies: an open-pit mine of rock materials and an underground hard coal mine. The selection of methods was set by the available data provided by the companies. The data for the analysis comes from internal documentation of the mines - financial statements, breakdowns and cost calculations.

Appearance of the pituitary factor Pit-1 increases chromatin remodeling at hypersensitive site III in the human GH locus.

PubMed

Yang, Xiaoyang; Jin, Yan; Cattini, Peter A

2010-07-01

Expression of pituitary and placental members of the human GH and chorionic somatomammotropin (CS) gene family is directed by an upstream remote locus control region (LCR). Pituitary-specific expression of GH requires direct binding of Pit-1 (listed as POU1F1 in the HUGO database) to sequences marked by a hypersensitive site (HS) region (HS I/II) 14.6 kb upstream of the GH-N gene (listed as GH1 in the HUGO database). We used human embryonic kidney 293 (HEK293) cells overexpressing wild-type and mutant Pit-1 proteins as a model system to gain insight into the mechanism by which Pit-1 gains access to the GH LCR. Addition of Pit-1 to these cells increased DNA accessibility at HS III, located 28 kb upstream of the human GH-N gene, in a POU homeodomain-dependent manner, as reflected by effects on histone hyperacetylation and RNA polymerase II activity. Direct binding of Pit-1 to HS III sequences is not supported. However, the potential for binding of ETS family members to this region has been demonstrated, and Pit-1 association with this ETS element in HS III sequences requires the POU homeodomain. Also, both ETS1 and ELK1 co-precipitate from human pituitary extracts using two independent sources of Pit-1 antibodies. Finally, overexpression of ELK1 or Pit-1 expression in HEK293 cells increased GH-N RNA levels. However, while ELK1 overexpression also stimulated placental CS RNA levels, the effect of Pit-1 appeared to correlate with ETS factor levels and target GH-N preferentially. These data are consistent with recruitment and an early role for Pit-1 in remodeling of the GH LCR at the constitutively open HS III through protein-protein interaction.

Modeling pitting corrosion of iron exposed to alkaline solutions containing nitrate and nitrite

NASA Astrophysics Data System (ADS)

Chen, Lifeng

2001-07-01

Pitting corrosion could be extremely serious for dilute high-level radioactive waste stored or processed in carbon steel tanks at the Savannah River Site. In these solutions, nitrate is an aggressive ion with respect to pitting of carbon steel while nitrite can be used as an inhibitor. Excessive additions of nitrite increase the risk of generating unstable nitrogen compounds during waste processing, and insufficient additions of nitrite could increase the risk of corrosion-induced failure. Thus there are strong incentives to obtain a fundamental understanding of the role of nitrite in pitting corrosion prevention with these solution chemistries. In this dissertation, both a 1-D and a 2-D model are used to study the pitting mechanism as a function of nitrite/nitrate ratios. The 1-D model used BAND(J) to test a reaction mechanism for the passivation behavior by comparing the predicted Open Circuit Potential (OCP) with OCP data from experiments at different NO2-/NO3- ratio. The model predictions are compared with Cyclic Potentiodynamic Polarization (CPP) experiments. A 2-D model was developed for the propagation of a pit in iron by writing subroutines for finite element software of GAMBIT and FIDAP. Geometrically distributed anodic and cathodic reactions are assumed. The results show three partial explanations describing the inhibition influence of nitrite to iron corrosion: the competing reduction reaction of nitrate to nitrite, the formation of Fe(OH)+, and the function of the porous film. The current distributions and the effect of porosity of the film on pH are also explained. The calculation results also show that rate of pit growth decreases as the pit diameter increases until it reaches a constant value. The profile of the local current density on the pit wall is parabolic for small pits and it changes to a linear distribution for large pits. The model predicts that addition of nitrite will decrease the production of ferrous ions and those can prevent iron from dissolving. Also nitrate ion will accumulate in the pit if not enough inhibitor is added to the solution, and this will accelerate pit growth.

Pedoturbation by tree uprooting: the key pattern-forming factor in the forest soil

NASA Astrophysics Data System (ADS)

Bobrovsky, Maxim; Loyko, Sergey

2017-04-01

Treefalls with uprooting are the most powerful and ubiquitous biotic factor changing the structure of forest soil under free forest development. Practically every soil profile in a forest has a number of soil horizons anomalies which are located within the limits of the potential depth of treefall-related pedoturbations and these anomalies are indeed a result of treefalls in most cases. It is important to recognize signs of treefalls with uprooting in a soil profile even when signs of treefalls on the ground surface (pit-and-mound topography) are erased. Numerous field studies of forest soil in the European part of Russia and in the Western Siberia allowed us to generalize signs of treefalls in a soil profile, which can be used to distinguish the patterns of old treefall-related pedoturbations. We distinguish two main types of uprooting of a fallen tree: hinge and rotational tree uprooting (treefall). The signs of treefalls with uprooting in a soil profile are as follows: (1) treefall pits (cauldrons); (2) spotty or streaky structures of different degrees of contrast; (3) blocks of "buried material" from the upper soil layers; (4) washed (bleached) material depositing at the bottom of pits and filling soil pores and channels of various origins; (5) signs of hydrogenous changes of soil material resulting from water stagnation in the pits; (6) root channels at the bottom of the pit and (7) inclusions of litter and charcoal. We cleared that treefall-related pedoturbations affect soil profiles at a depth larger than the depth usually described by the soil horizons A, E, Bhs, etc. Therefore in most forest soils, the middle and lower parts of the profiles have patterns originating from the transfer of soil material upon treefalls. Age since the tree uprooting can be determined by dating of organic matter or charcoal located in old pits. We dated several tens of old tree uprooting pits by charcoal in sandy soil in the center and the east of the Russian Plain: they showed from a few hundreds to 4500 cal years BP. We also dated tens of old tree uprooting pits by mull humus in Luvic Phaeozems on loams in the center of the Russian Plain: they showed from 2500 to more than 8000 cal years BP. Discerning of old treefall-related patterns in soil profile significantly improves our understanding of the forest soil formation and leads to the necessity of serious corrections of pedogenesys concepts. This study was partly supported by the Russian Science Foundation (Grant 16-17-10045).

Ablation layers to prevent pitting in laser peening

DOEpatents

Hackel, Lloyd A

2016-08-09

A hybrid ablation layer that comprises a separate under layer is applied to a material to prevent pitting resulting from laser peening. The underlayer adheres to the surface of the workpiece to be peened and does not have bubbles and voids that exceed an acceptable size. One or more overlayers are placed over and in contact with the underlayer. Any bubbles formed under the over layers are insulated from the surface to be peened. The process significantly reduces the incidence of pits on peened surfaces.

Modelling cavitation erosion using fluid–material interaction simulations

PubMed Central

Chahine, Georges L.; Hsiao, Chao-Tsung

2015-01-01

Material deformation and pitting from cavitation bubble collapse is investigated using fluid and material dynamics and their interaction. In the fluid, a novel hybrid approach, which links a boundary element method and a compressible finite difference method, is used to capture non-spherical bubble dynamics and resulting liquid pressures efficiently and accurately. The bubble dynamics is intimately coupled with a finite-element structure model to enable fluid/structure interaction simulations. Bubble collapse loads the material with high impulsive pressures, which result from shock waves and bubble re-entrant jet direct impact on the material surface. The shock wave loading can be from the re-entrant jet impact on the opposite side of the bubble, the fast primary collapse of the bubble, and/or the collapse of the remaining bubble ring. This produces high stress waves, which propagate inside the material, cause deformation, and eventually failure. A permanent deformation or pit is formed when the local equivalent stresses exceed the material yield stress. The pressure loading depends on bubble dynamics parameters such as the size of the bubble at its maximum volume, the bubble standoff distance from the material wall and the pressure driving the bubble collapse. The effects of standoff and material type on the pressure loading and resulting pit formation are highlighted and the effects of bubble interaction on pressure loading and material deformation are preliminarily discussed. PMID:26442140

[Pit-picking surgery for pilonidal disease].

PubMed

Iesalnieks, I; Deimel, S; Kienle, K; Schlitt, H J; Zülke, C

2011-10-01

The pit-picking method was first described by J. Bascom in 1980, however, this minimally invasive technique is used only by a minority of surgeons yet. Surgery was performed under local anesthesia. All primary pits in the midline were removed by excising a border of skin of <1 mm and a 1 cm long incision was made parallel to one side of the cleft to open the chronic abscess cavity. No specific postoperative wound care was given. Pit-picking surgery was carried out 157 times in a total of 153 patients (126 males) between June 2007 and November 2010. Follow-up information was available in 123 cases and 21 patients (17%) developed disease recurrence after a mean follow-up time of 7.1 months. By multivariate analysis, a body mass index (BMI) >25 kg/m(2) (p=0.019) and duration of the disease of ≥6 months (p=0.017) were statistically significantly associated with disease recurrence after pit-picking surgery. The recurrence occurred more often in male than in female patients (20% versus 4.5%, p=0.12) Patients with pilonidal disease can be successfully treated by the pit-picking procedure in more than 80% of selected cases. Female patients and non-overweight male patients with short-term disease benefit most from this treatment method.

Study of Etching Pits in a Large-grain Single Cell Bulk Niobium Cavity

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

Zhao, Xin; Ciovati, Gianluigi; Reece, Charles E.

2009-11-01

Performance of SRF cavities are limited by non-linear localized effects. The variation of local material characters between "hot" and "cold" spots is thus of intense interest. Such locations were identified in a BCP-etched large-grain single-cell cavity and removed for examination by high resolution electron microscopy (SEM), electron-back scattering diffraction microscopy (EBSD), optical microscopy, and 3D profilometry. Pits with clearly discernable crystal facets were observed in both "hotspot" and "coldspot" specimens. The pits were found in-grain, at bi-crystal boundaries, and on tri-crystal junctions. They are interpreted as etch pits induced by surface crystal defects (e.g. dislocations). All "coldspots" examined had qualitativelymore » low density of etching pits or very shallow tri-crystal boundary junction. EBSD revealed crystal structure surrounding the pits via crystal phase orientation mapping, while 3D profilometry gave information on the depth and size of the pits. In addition, a survey of the samples by energy dispersive X-ray analysis (EDX) did not show any significant contamination of the samples surface.« less

Building pit dewatering: application of transient analytic elements.

PubMed

Zaadnoordijk, Willem J

2006-01-01

Analytic elements are well suited for the design of building pit dewatering. Wells and drains can be modeled accurately by analytic elements, both nearby to determine the pumping level and at some distance to verify the targeted drawdown at the building site and to estimate the consequences in the vicinity. The ability to shift locations of wells or drains easily makes the design process very flexible. The temporary pumping has transient effects, for which transient analytic elements may be used. This is illustrated using the free, open-source, object-oriented analytic element simulator Tim(SL) for the design of a building pit dewatering near a canal. Steady calculations are complemented with transient calculations. Finally, the bandwidths of the results are estimated using linear variance analysis.

Potentiodynamic Corrosion Testing.

PubMed

Munir, Selin; Pelletier, Matthew H; Walsh, William R

2016-09-04

Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation potential of the material. The detection of these electrochemical parameters identifies the corrosion factors of a material. A reliable and well-functioning corrosion system is required to achieve this. Corrosion of the samples was achieved via a potentiodynamic polarization technique employing a three-electrode configuration, consisting of reference, counter, and working electrodes. Prior to commencement a baseline potential is obtained. Following the stabilization of the corrosion potential (Ecorr), the applied potential is ramped at a slow rate in the positive direction relative to the reference electrode. The working electrode was a stainless steel screw. The reference electrode was a standard Ag/AgCl. The counter electrode used was a platinum mesh. Having a reliable and well-functioning in vitro corrosion system to test biomaterials provides an in-expensive technique that allows for the systematic characterization of the material by determining the breakdown potential, to further understand the material's response to corrosion. The goal of the protocol is to set up and run an in vitro potentiodynamic corrosion system to analyze pitting corrosion for small metallic medical devices.

STS-48 crew participates in JSC fire fighting and fire training exercises

NASA Technical Reports Server (NTRS)

1991-01-01

STS-48 Mission Specialist (MS) Charles D. Gemar opens water hose nozzle as he approaches a fire blazing in JSC's Fire Training Pit during fire fighting and fire training exercises. Pilot Kenneth S. Reightler, Jr steadies the hose behind Gemar. At Gemars right is an unidentified fire department Official, MS Mark N. Brown, and Commander John O. Creighton. Brown and Crieghton are obscured by the water spray. The Fire Training Pit is located across from the Gilruth Center Bldg 207.

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

Grogin, Phillip W.

A powered industrial truck (PIT) is defined as a mobile, powerdriven vehicle used to carry, push, pull, lift, or stack material (not including vehicles intended primarily for earth moving). There are many types of and names for PITs, including forklifts, trucks, fork trucks, platform lift trucks, motorized hand trucks, and tractors. Although not every PIT is a forklift, because PITs are commonly called “forklifts,” this course manual generally uses the term “forklift,” although at times the terms “truck” and “PIT” are also used. In some areas of this course, you will see green boxes that refer to the Occupational Safetymore » and Health Administration (OSHA) regulation for PITs, which is 29 Code of Federal Regulations (CFR) 1910.178, Powered Industrial Trucks. The letter in the parentheses refers to the specific section of the regulation.« less

Uranium in mining water of kaolin open pit in Zarów (Lower Silesia); methodology of determination and genetic remarks.

PubMed

Chau, N D; Wyszomirski, P; Chruściel, E; Ochoński, A

1999-11-01

In this paper, a method of determination of uranium 238 and 234 in mining waters of Andrzej kaolin open pit in Zarów (Lower Silesia) is presented. The method is based on independent measurements of alpha and beta radiation intensities by means of a liquid scintillation spectrometer alpha/beta. The initial volume of water sample was 3 dm3, then it was diminished by chemical preparation to 6 cm3, and then 12 cm3 of scintillator was added. The lower limit of detection (for the measurement time of 8 h) for both 234U and 238U amounted to 0.02 Bq/dm3. For determination of the uranium content in ferruginous sediments precipitating from mining waters of the above-mentioned open pit, gamma ray spectrometry was used. The obtained results may be viewed as a contribution to studies on anomalous uranium concentration within this kaolin deposit. The elevated uranium content, in comparison with its average concentration in the Earth crust, is characteristic for parent rocks of Andrzej kaolin deposit, which are granitoids of Strzegom-Sobótka massif. In connection with it, the high uranium content can be observed not only in kaolin and weakly kaolinised granitoids from the deposit in question, but also in mining waters genetically related with them.

The use of vibration monitoring to record the blasting works impact on buildings surrounding open-pit mines

NASA Astrophysics Data System (ADS)

Sołtys, Anna; Pyra, Józef; Winzer, Jan

2018-04-01

Environmental protection law and geological and mining law require the mineral mining plant to protect its surroundings from the effects of mining operations. This also applies to the negative impact of vibrations induced by blasting works on people and construction facilities. Effective protection is only possible if the level of this impact is known, therefore it is necessary to record it. The thesis formulated in this way has been and continues to be the guiding principle of the research works carried out in the AGH Laboratory of Blasting Work and Environmental Protection. As a result of these works are procedures for conducting preventive activities by open-pit mines in order to minimize the impact of blasting on facilities in the surrounding area. An important element of this activity is the monitoring of vibrations in constructions, which is a source of knowledge for excavation supervisors and engineers performing blasting works, thus contributing to raising the awareness of the responsible operation of the mining plant. Developed in the Laboratory of the Mine's Vibration Monitoring Station (KSMD), after several modernizations, it became a fully automated system for monitoring and recording the impact of blasting works on the surrounding environment. Currently, there are 30 measuring devices in 10 open-pit mines, and additional 8 devices are used to provide periodic measurement and recording services for the mines concerned.

Cleanup Verification Package for the 100-F-20, Pacific Northwest Laboratory Parallel Pits

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

M. J. Appel

2007-01-22

This cleanup verification package documents completion of remedial action for the 100-F-20, Pacific Northwest Laboratory Parallel Pits waste site. This waste site consisted of two earthen trenches thought to have received both radioactive and nonradioactive material related to the 100-F Experimental Animal Farm.

Morphological Evolution of Pit-Patterned Si(001) Substrates Driven by Surface-Energy Reduction

NASA Astrophysics Data System (ADS)

Salvalaglio, Marco; Backofen, Rainer; Voigt, Axel; Montalenti, Francesco

2017-09-01

Lateral ordering of heteroepitaxial islands can be conveniently achieved by suitable pit-patterning of the substrate prior to deposition. Controlling shape, orientation, and size of the pits is not trivial as, being metastable, they can significantly evolve during deposition/annealing. In this paper, we exploit a continuum model to explore the typical metastable pit morphologies that can be expected on Si(001), depending on the initial depth/shape. Evolution is predicted using a surface-diffusion model, formulated in a phase-field framework, and tackling surface-energy anisotropy. Results are shown to nicely reproduce typical metastable shapes reported in the literature. Moreover, long time scale evolutions of pit profiles with different depths are found to follow a similar kinetic pathway. The model is also exploited to treat the case of heteroepitaxial growth involving two materials characterized by different facets in their equilibrium Wulff's shape. This can lead to significant changes in morphologies, such as a rotation of the pit during deposition as evidenced in Ge/Si experiments.

Morphological Evolution of Pit-Patterned Si(001) Substrates Driven by Surface-Energy Reduction.

PubMed

Salvalaglio, Marco; Backofen, Rainer; Voigt, Axel; Montalenti, Francesco

2017-09-29

Lateral ordering of heteroepitaxial islands can be conveniently achieved by suitable pit-patterning of the substrate prior to deposition. Controlling shape, orientation, and size of the pits is not trivial as, being metastable, they can significantly evolve during deposition/annealing. In this paper, we exploit a continuum model to explore the typical metastable pit morphologies that can be expected on Si(001), depending on the initial depth/shape. Evolution is predicted using a surface-diffusion model, formulated in a phase-field framework, and tackling surface-energy anisotropy. Results are shown to nicely reproduce typical metastable shapes reported in the literature. Moreover, long time scale evolutions of pit profiles with different depths are found to follow a similar kinetic pathway. The model is also exploited to treat the case of heteroepitaxial growth involving two materials characterized by different facets in their equilibrium Wulff's shape. This can lead to significant changes in morphologies, such as a rotation of the pit during deposition as evidenced in Ge/Si experiments.

Craters Near Nilokeras Scopulus

NASA Image and Video Library

2015-03-04

This image from NASA Mars Reconnaissance Orbiter of craters near Nilokeras Scopulus shows two pits partially filled with lumpy material, probably trapped dust that blew in from the atmosphere. This image shows two pits partially filled with lumpy material, probably trapped dust that blew in from the atmosphere. The pits themselves resemble impact craters, but they are part of a chain of similar features aligned with nearby faults, so they could be collapse features instead. Note also the tracks left by rolling boulders at the bottom of the craters. Nilokeras Scopulus is the name for the cliff, about 756 kilometers long, in the northern hemisphere of Mars where these craters are located. It was named based on an albedo (brightness) feature mapped by astronomer E. M. Antoniadi in 1930. http://photojournal.jpl.nasa.gov/catalog/PIA19304

78 FR 54956 - Agency Information Collection (Open Burn Pit Registry Airborne Hazard Self-Assessment...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-06

... Control No. 2900- 0766'' in any correspondence. FOR FURTHER INFORMATION CONTACT: Crystal Rennie... 20420, (202) 632-7492 or email crystal[email protected] . Please refer to ``OMB Control No. 2900-NEW, Open... over time through routine and adhoc analysis to improve health care programs and develop hypotheses for...

A crossover study of rosuvastatin and pitavastatin in patients with type 2 diabetes.

PubMed

Yanagi, Kazunori; Monden, Tsuyoshi; Ikeda, Shiori; Matsumura, Mihoko; Kasai, Kikuo

2011-02-01

The effects of a low dose of rosuvastatin (ROS) and pitavastatin (PIT) on lipid profiles and inflammation markers were assessed in subjects with type 2 diabetes mellitus. A total of 90 Japanese type 2 diabetes patients with hyperlipidemia (low-density lipoprotein cholesterol [LDL-C] ≥140 mg/dL) were enrolled in this study. They were randomly assigned to four groups with open-label treatment with ROS (2.5 mg daily) or PIT (2 mg daily); two groups were sequentially treated with both drugs, with crossover of medication after 12 weeks, and the other two groups underwent treatment with either ROS or PIT for 24 weeks. The primary endpoints were the percentage changes in LDL-C, high-density lipoprotein cholesterol (HDL-C) and triglyceride, and the LDL-C/HDL-C ratio. Both ROS and PIT lowered LDL-C and triglyceride, and increased HDL-C. In particular, significantly greater reduction in LDL-C was seen with ROS (-44.1%) than with PIT (-36.9%, P<0.01) in the crossover group from ROS to PIT, and the same result was detected in the crossover group from PIT (-34.8%) to ROS (-44.7%). The ratio of LDL-C/HDL-C was significantly reduced with ROS treatment (from 3.45 to 1.85) compared with that with PIT (from 3.45 to 2.22, P<0.01). Both ROS and PIT lowered plasma levels of high-sensitivity C-reactive protein (hsCRP), tumor necrosis factor (TNF)-alpha, and plasminogen activator inhibitor-1 (PAI-1). In addition, the hsCRP level with the administration of ROS was significantly improved compared with the administration of PIT. There was no significant correlation between changes in LDL-C and hsCRP, TNF-alpha, and PAI-1 levels. ROS and PIT did not have an adverse effect on glycemic control in type 2 diabetes patients. Therapy with both statins improved lipid profiles and reduced proinflammatory responses; however, 2.5 mg of ROS have a potent LDL-C-lowering and hsCRP-lowering effect compared with 2 mg of PIT in patients with diabetes.

Potential risk assessment in stream sediments, soils and waters after remediation in an abandoned W>Sn mine (NE Portugal).

PubMed

Antunes, I M H R; Gomes, M E P; Neiva, A M R; Carvalho, P C S; Santos, A C T

2016-11-01

The mining complex of Murçós belongs to the Terras de Cavaleiros Geopark, located in Trás-os-Montes region, northeast Portugal. A stockwork of NW-SE-trending W>Sn quartz veins intruded Silurian metamorphic rocks and a Variscan biotite granite. The mineralized veins contain mainly quartz, cassiterite, wolframite, scheelite, arsenopyrite, pyrite, sphalerite, chalcopyrite, galena, rare pyrrhotite, stannite, native bismuth and also later bismuthinite, matildite, joseite, roosveltite, anglesite, scorodite, zavaritskite and covellite. The exploitation produced 335t of a concentrate with 70% of W and 150t of another concentrate with 70% of Sn between 1948 and 1976. The exploitation took place mainly in four open pit mines as well as underground. Three lakes were left in the area. Remediation processes of confination and control of tailings and rejected materials and phytoremediation with macrophytes from three lakes were carried out between 2005 and 2007. Stream sediments, soils and water samples were collected in 2008 and 2009, after the remediation process. Most stream sediments showed deficiency or minimum enrichment for metals. The sequential enrichment factor in stream sediments W>Bi>As>U>Cd>Sn=Ag>Cu>Sb>Pb>Be>Zn is mainly associated with the W>Sn mineralizations. Stream sediments receiving drainage of a mine dump were found to be significantly to extremely enriched with W, while stream sediments and soils were found to be contaminated with As. Two soil samples collected around mine dumps and an open pit lake were also found to be contaminated with U. The waters from the Murçós W>Sn mine area were acidic to neutral. After the remediation, the surface waters were contaminated with F(-), Al, As, Mn and Ni and must not be used for human consumption, while open pit lake waters must also not be used for agriculture because of contamination with F(-), Al, Mn and Ni. In most waters, the As occurred as As (III), which is toxic and is easily mobilized in the drainage system. The remediation promoted a decrease in metals and As concentrations of soils and waters, however the applied processes were not enough to rehabilitate the area. Copyright © 2016 Elsevier Inc. All rights reserved.

Numerical Modeling to Assess DNAPL Movement and Removal at the Scenic Site Operable Unit Near Baton Rouge, Louisiana: A Case Study.

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

Oostrom, Mart; Thorne, Paul D.; White, Mark D.

2003-12-01

Detailed three-dimensional multifluid flow modeling was conducted to assess movement and removal of dense nonaqueous phase liquid (DNAPL) movement at a waste site in Louisiana. The site’s subsurface consists of several permeable zones separated by (semi) confining clays. In the upper subsurface, the two major permeable zones are, starting with the uppermost zone, the +40- and +20-MSL (mean sea level) zones. At the site, a total of 23,000 m3 of DNAPL was emplaced in an open waste pit between 1962 and 1974. In this period, considerable amounts of DNAPL moved into the subsurface. By 1974 a portion of the DNAPLmore » was removed and the waste site was filled with low-permeability materials and closed. During this process, some of the DNAPL was mixed with the fill material and remained at the site. Between 1974 and 2000, no additional DNAPL recovery activities were implemented. In an effort to reduce the DNAPL source, organic liquid has been pumped through a timed-pumping scheme from a total of 7 wells starting in calendar year 2000. The recovery wells are screened in the lower part of the waste fill material. In site investigations, DNAPL has been encountered in the +40-MSL but not in the +20-MSL zone. The following questions are addressed: (1) Where has the DNAPL migrated vertically and laterally? (2) How much further is DNAPL expected to move in the next century? (3) How effective is the current DNAPL pumping in reducing the DNAPL source? The computational domains for the simulations were derived from 3-D interpolations of borehole logs using a geologic interpretation software (EarthvisionTM ) . The simulation results show that DNAPL primarily entered the subsurface in the period 1962 – 1974, when the waste site was operational. After 1974, the infiltration rates dropped dramatically as a result of the infilling of the waste pit. The simulation results indicate that DNAPL moved from the pit into the underlying +40-MSL zone through two contact zones at the west side of the pit. Lateral movement of the DNAPL body has been relatively slow as a result of the high viscosity and the rapidly decreasing driving force after the waste pit was filled in. For all simulations, lateral movement of DNAPL in the period 1962 - 2001 is predicted to be less than 60 m from the two contact areas, while additional movement in the next century is expected to be less than 30 m. No DNAPL is predicted to enter the +20-MSL zone, which agrees with site information. The simulations also clearly demonstrate the minimal effect of the current pumping scheme on source reduction and DNAPL movement.« less

Localized corrosion behaviour in simulated human body fluids of commercial Ni-Ti orthodontic wires.

PubMed

Rondelli, G; Vicentini, B

1999-04-01

The corrosion performances in simulated human body fluids of commercial equiatomic Ni-Ti orthodontic wires having various shape and size and produced by different manufacturers were evaluated; for comparison purposes wires made of stainless steel and of cobalt-based alloy were also examined. Potentiodynamic tests in artificial saliva at 40 degrees C indicated a sufficient pitting resistance for the Ni-Ti wires, similar to that of cobalt-based alloy wire; the stainless steel wire, instead, exhibited low pitting potential. Potentiodynamic tests at 40 degrees C in isotonic saline solution (0.9% NaCl) showed, for Ni-Ti and stainless steel wires, pitting potential values in the range approximately 200-400 mV and approximately 350 mV versus SCE, respectively: consequently, according to literature data (Hoar TP, Mears DC. Proc Roy Soc A 1996;294:486-510), these materials should be considered potentially susceptible to pitting; only the cobalt-based alloy should be immune from pitting. The localized corrosion potentials determined in the same environment by the ASTM F746 test (approximately 0-200 mV and 130 mV versus SCE for Ni-Ti and stainless steel, respectively) pointed out that for these materials an even higher risk of localized corrosion. Slight differences in localized corrosion behaviour among the various Ni-Ti wires were detected.

Characterization of erosion of metallic materials under cavitation attack in a mineral oil

NASA Technical Reports Server (NTRS)

Rao, B. C. S.; Buckley, D. H.

1985-01-01

Cavitation erosion and erosion rates of eight metallic materials representing three crystal structures were studied. The erosion experiments were conducted with a 20-kHz ultrasonic magnetostrictive oscillator in a viscous mineral oil. The erosion rates of the metals with an fcc matrix were 10 to 100 times higher than that of an hop-matrix titanium alloy. The erosion rates of iron and molybdenum, with bcc matrices, were higher than that of the titanium alloy but lower than those of those of the fcc materials. Studies with scanning electron microscopy indicated that the cavitation pits were initially formed at the grain boundaries and precipitates and that the pits formed at the junction of grain boundaries grew faster than the others. Transcrystalline craters formed by cavitation attack over the surface of grains and roughened the surfaces by multiple slip and twinning. Surface roughness measurements showed that the pits that formed over the grain boundaries deepened faster than pits. Computer analysis revealed that a geometric expression describes the nondimensional erosion curves during the time period 0.5 t (sub 0) t 2.5 t (sub 0), where t (sub 0) is the incubation period. The fcc metals had very short incubation periods; the titanium alloy had the longest incubation period.

Estimating disperser abundance using open population models that incorporate data from continuous detection PIT arrays

USGS Publications Warehouse

Dzul, Maria C.; Yackulic, Charles B.; Korman, Josh

2017-01-01

Autonomous passive integrated transponder (PIT) tag antenna systems continuously detect individually marked organisms at one or more fixed points over long time periods. Estimating abundance using data from autonomous antennae can be challenging, because these systems do not detect unmarked individuals. Here we pair PIT antennae data from a tributary with mark-recapture sampling data in a mainstem river to estimate the number of fish moving from the mainstem to the tributary. We then use our model to estimate abundance of non-native rainbow trout Oncorhynchus mykiss that move from the Colorado River to the Little Colorado River (LCR), the latter of which is important spawning and rearing habitat for federally-endangered humpback chub Gila cypha. We estimate 226 rainbow trout (95% CI: 127-370) entered the LCR from October 2013-April 2014. We discuss the challenges of incorporating detections from autonomous PIT antenna systems into mark-recapture population models, particularly in regards to using information about spatial location to estimate movement and detection probabilities.

Application of wire beam electrode technique to investigate initiation and propagation of rebar corrosion

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

Shi, Wei; Dong, Ze Hua, E-mail: zehua.dong@gmail.com; Kong, De Jie

Multi-electrode technique named as wire beam electrode (WBE) was used to study pitting corrosion of rebar under concrete cover. When WBE embedded mortar sample was immersed in NaCl solution, uneven distributions of galvanic current and open circuit potential (OCP) on the WBE were observed due to the initiation of pitting corrosion. The following oxygen depletion in mortar facilitated the negative shift of the OCP and the smoothing of the current and potential distributions. Wetting–drying cycle experiments showed that corrosion products instead of oxygen in wet mortar specimen sustained the propagation of pitting corrosion due to Fe (III) taking part inmore » cathodic depolarization during oxygen-deficient wet period, which was confirmed by micro-Raman spectroscopy. In addition, new pitting corrosion occurred mainly near the corrosion products, leading to preferentially horizontal propagation of rust layer on the WBE. A localized corrosion factor was further presented to quantify the localised corrosion based on galvanic current maps.« less

Technology and Organisation of Inka Pottery Production in the Leche Valley. Part II: Study of Fired Vessels

NASA Astrophysics Data System (ADS)

Hayashida, F.; Häusler, W.; Riederer, J.; Wagner, U.

2003-09-01

Ceramic finds from the Inka workshops at Tambo Real and La Viña in the Leche Valley in northern Peru were studied by Mössbauer spectroscopy, thin section microscopy and X-ray diffraction. Sherds of Inka style vessels and of local style vessels can be distinguished by their shape, although local techniques appear to have been used in making both types. A reconstruction of the firing techniques by scientific studies of the ceramic material does not reveal a substantial difference in material or in the firing of both forms, although high firing temperatures were necessary to achieve sufficient stability of the large Inka style vessels. It cannot be decided whether the smaller local vessels were fired together with the Inka vessels or separately. Most of the variation in the maximum firing temperature can be explained with the normal temperature and atmosphere fluctuations in an open pit kiln.

Direct observation of pitting corrosion evolutions on carbon steel surfaces at the nano-to-micro- scales.

PubMed

Guo, Peng; La Plante, Erika Callagon; Wang, Bu; Chen, Xin; Balonis, Magdalena; Bauchy, Mathieu; Sant, Gaurav

2018-05-22

The Cl - -induced corrosion of metals and alloys is of relevance to a wide range of engineered materials, structures, and systems. Because of the challenges in studying pitting corrosion in a quantitative and statistically significant manner, its kinetics remain poorly understood. Herein, by direct, nano- to micro-scale observations using vertical scanning interferometry (VSI), we examine the temporal evolution of pitting corrosion on AISI 1045 carbon steel over large surface areas in Cl - -free, and Cl - -enriched solutions. Special focus is paid to examine the nucleation and growth of pits, and the associated formation of roughened regions on steel surfaces. By statistical analysis of hundreds of individual pits, three stages of pitting corrosion, namely, induction, propagation, and saturation, are quantitatively distinguished. By quantifying the kinetics of these processes, we contextualize our current understanding of electrochemical corrosion within a framework that considers spatial dynamics and morphology evolutions. In the presence of Cl - ions, corrosion is highly accelerated due to multiple autocatalytic factors including destabilization of protective surface oxide films and preservation of aggressive microenvironments within the pits, both of which promote continued pit nucleation and growth. These findings offer new insights into predicting and modeling steel corrosion processes in mid-pH aqueous environments.

Impact of Annealing Prior to Solution Treatment on Aging Precipitates and Intergranular Corrosion Behavior of Al-Cu-Li Alloy 2050

NASA Astrophysics Data System (ADS)

Ye, Zhi-hao; Cai, Wen-xin; Li, Jin-feng; Chen, Xiang-rong; Zhang, Rui-feng; Birbilis, Nick; Chen, Yong-lai; Zhang, Xu-hu; Ma, Peng-cheng; Zheng, Zi-qiao

2018-06-01

The influences of annealing prior to solution treatment on the grain structure, subsequent aging precipitates, and intergranular corrosion (IGC) of Al-Cu-Li alloy (AA2050) sheet with T6 aging at 448 K (175 °C) were investigated. Annealing impedes the full recrystallization during solution treatment, increasing the population density of T1 (Al2CuLi) precipitates, but decreasing that of θ' (Al2Cu) precipitates, of the aged alloy. Meanwhile, annealing leads to the heterogeneous distribution of T1 precipitates, increasing the alloy hardness, and decreasing the open-circuit potential of the aged alloy. With prolonged aging time, the corrosion mode of the aged AA2050 samples with and without annealing evolved in a similar manner. The corrosion mode as a function of aging may be summarized as local IGC with pitting and general IGC with pitting (following initial aging and under the underaged condition), pitting corrosion (later in the under-aging stage), pitting with slight IGC (near the peak-aged condition), and pitting with local IGC (under the overaging condition). The annealing treatment hinders IGC propagation on the rolling surface while accelerating the IGC on transverse surfaces.

Impact of Annealing Prior to Solution Treatment on Aging Precipitates and Intergranular Corrosion Behavior of Al-Cu-Li Alloy 2050

NASA Astrophysics Data System (ADS)

Ye, Zhi-hao; Cai, Wen-xin; Li, Jin-feng; Chen, Xiang-rong; Zhang, Rui-feng; Birbilis, Nick; Chen, Yong-lai; Zhang, Xu-hu; Ma, Peng-cheng; Zheng, Zi-qiao

2018-04-01

The influences of annealing prior to solution treatment on the grain structure, subsequent aging precipitates, and intergranular corrosion (IGC) of Al-Cu-Li alloy (AA2050) sheet with T6 aging at 448 K (175 °C) were investigated. Annealing impedes the full recrystallization during solution treatment, increasing the population density of T1 (Al2CuLi) precipitates, but decreasing that of θ' (Al2Cu) precipitates, of the aged alloy. Meanwhile, annealing leads to the heterogeneous distribution of T1 precipitates, increasing the alloy hardness, and decreasing the open-circuit potential of the aged alloy. With prolonged aging time, the corrosion mode of the aged AA2050 samples with and without annealing evolved in a similar manner. The corrosion mode as a function of aging may be summarized as local IGC with pitting and general IGC with pitting (following initial aging and under the underaged condition), pitting corrosion (later in the under-aging stage), pitting with slight IGC (near the peak-aged condition), and pitting with local IGC (under the overaging condition). The annealing treatment hinders IGC propagation on the rolling surface while accelerating the IGC on transverse surfaces.

Successful remediation of four uranium calibration pits at Technical Area II, Sandia National Laboratories, Albuquerque, New Mexico, USA

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

Conway, R.; Wade, M.; Tharp, T.

1994-12-31

The first remediation of an Environmental Restoration (ER) Project site at Sandia National Laboratories (SNL) was successfully conducted in May and June 1994 at Technical Area II. The removal action involved four Uranium Calibration Pits (UCPs) filled with radioactive or hazardous materials. The concrete culvert pits were used to test and calibrate borehole radiometric logging tools for uranium exploration. The removal action consisted of excavating and containerizing the pit contents and contaminated soil beneath the culverts, removing the four culverts, and backfilling the excavation. Each UCP removal had unique complexities. Sixty 208-L drums of solid radioactive waste and eight 208-Lmore » drums of liquid hazardous waste were generated during the VCM. Two of the concrete culverts will be disposed as radioactive waste and two as solid waste. Uranium-238 was detected in UCP-2 ore material at 746 pci/g, and at 59 pci/g in UCP-1 silica sand. UCP-4 was empty; sludge from UCP-3 contained 122 mg/L (ppm) chromium.« less

Pitting and stress corrosion cracking of stainless steel

NASA Astrophysics Data System (ADS)

Saithala, Janardhan R.

An investigation has been performed to determine the pitting resistance of stainless steels and stress corrosion cracking of super duplex stainless steels in water containing chloride ions from 25 - 170°C. The steels studied are 12% Cr, FV520B, FV566, 304L, Uranus65, 2205, Ferallium Alloy 255, and Zeron 100. All these commercial materials used in very significant industrial applications and suffer from pitting and stress corrosion failures. The design of a new experimental setup using an autoclave enabled potentiodynamic polarisation experiments and slow strain rate tests in dilute environments to be conducted at elevated temperatures. The corrosion potentials were controlled using a three electrode cell with computer controlled potentiostat.The experimental programme to determine pitting potentials was designed to simulate the service conditions experienced in most industrial plants and develop mathematical model equations to help a design engineer in material selection decision. Stress corrosion resistance of recently developed Zeron100 was evaluated in dilute environments to propose a mechanism in chloride solutions at high' temperatures useful for the nuclear and power generation industry. Results have shown the significance of the composition of alloying elements across a wide range of stainless steels and its influence on pitting. Nitrogen and molybdenum added to modern duplex stainless steels was found to be unstable at higher temperatures. The fractographic results obtained using the scanning electron microscope (SEM) has given insight in the initiation of pitting in modem duplex and super duplex stainless steels. A mathematical model has been proposed to predict pitting in stainless steels based on the effect of environmental factors (temperature, chloride concentration, and chemical composition). An attempt has been made to identify the mechanism of SCC in Zeron100 super duplex stainless steel.The proposed empirical models have shown good correlation between predicted pitting potential values with experimental results. It has been shown that the SCC mechanism in Zeron100 supports the slip assisted anodic dissolution model of SCC. The relationship between pitting and stress corrosion in dilute environments is established and empirical equations have been proposed to determine the damage region for wide range of stainless steels.

Project W-314 acceptance test report HNF-4647 for HNF-4646 241-B pit leak detection ANB-WT-LDSTA-231 for project W-314

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

HAMMERS, J.S.

The purpose of the test was to verify that the AN Tank Farm B Pit Leak Detector components are functionally integrated and operate in accordance with engineering design specifications. The Acceptance Test Procedure HNF-4646,241-AN-B-Pit Leak Detection ANB-WT-LDSTA-231 was conducted between 26 June and 02 July 1999 at the 200E AN Tank Farm. The test has been completed with no open test exceptions. The test was conducted prior to final engineering ''as built'' activities being completed this had no impact on the procedure or test results. All components, identified in the procedure were found to be labeled and identified as writtenmore » in the procedure.« less

Single-step inline hydroxyapatite enrichment facilitates identification and quantitation of phosphopeptides from mass-limited proteomes with MudPIT

PubMed Central

Fonslow, Bryan R.; Niessen, Sherry M.; Singh, Meha; Wong, Catherine C.; Xu, Tao; Carvalho, Paulo C.; Choi, Jeong; Park, Sung Kyu; Yates, John R.

2012-01-01

Herein we report the characterization and optimization of single-step inline enrichment of phosphopeptides directly from small amounts of whole cell and tissue lysates (100 – 500 μg) using a hydroxyapatite (HAP) microcolumn and Multidimensional Protein Identification Technology (MudPIT). In comparison to a triplicate HILIC-IMAC phosphopeptide enrichment study, ~80% of the phosphopeptides identified using HAP-MudPIT were unique. Similarly, analysis of the consensus phosphorylation motifs between the two enrichment methods illustrates the complementarity of calcium-and iron-based enrichment methods and the higher sensitivity and selectivity of HAP-MudPIT for acidic motifs. We demonstrate how the identification of more multiply phosphorylated peptides from HAP-MudPIT can be used to quantify phosphorylation cooperativity. Through optimization of HAP-MudPIT on a whole cell lysate we routinely achieved identification and quantification of ca. 1000 phosphopeptides from a ~1 hr enrichment and 12 hr MudPIT analysis on small quantities of material. Finally, we applied this optimized method to identify phosphorylation sites from a mass-limited mouse brain region, the amygdala (200 – 500 μg), identifying up to 4000 phosphopeptides per run. PMID:22509746

Antibiotic resistance profiles of coagulase-positive and coagulase-negative staphylococci from pit latrine fecal sludge in a peri-urban South African community.

PubMed

Beukes, Lorika S; Schmidt, Stefan

2018-04-16

The aim of this study was to assess pit latrine samples from a peri-urban community in KwaZulu-Natal (South Africa) for the presence of multidrug-resistant (MDR) Staphylococcus spp. Standard procedures were used to isolate Staphylococcus spp. from pit latrine fecal sludge samples, with confirmation at genus level by polymerase chain reaction (PCR). Sixty-eight randomly selected pit latrine Staphylococcus spp. isolates were further characterized by using established disk diffusion procedures. An average Staphylococcus spp. count of 2.1 × 10 5  CFU per g fecal material was established using two randomly selected pit latrine samples. Of the 68-selected Staphylococcus spp. pit latrine isolates, 49% were identified as coagulase positive, 51% as coagulase negative and 65% (12 coagulase positive, 32 coagulase negative isolates) were categorized as MDR. The majority (66/68) of Staphylococcus spp. isolates displayed resistance to fusidic acid while only 5/68 isolates displayed resistance to chloramphenicol. The pit latrine samples analyzed in this study are a source of MDR Staphylococcus spp., highlighting the need for proper hygiene and sanitation regimes in rural communities using these facilities.

Numerical modelling of the groundwater inflow to an advancing open pit mine: Kolahdarvazeh pit, Central Iran.

PubMed

Bahrami, Saeed; Doulati Ardejani, Faramarz; Aslani, Soheyla; Baafi, Ernest

2014-12-01

The groundwater inflow into a mine during its life and after ceasing operations is one of the most important concerns of the mining industry. This paper presents a hydrogeological assessment of the Irankuh Zn-Pb mine at 20 km south of Esfahan and 1 km northeast of Abnil in west-Central Iran. During mine excavation, the upper impervious bed of a confined aquifer was broken and water at high-pressure flowed into an open pit mine associated with the Kolahdarvazeh deposit. The inflow rates were 6.7 and 1.4 m(3)/s at the maximum and minimum quantities, respectively. Permeability, storage coefficient, thickness and initial head of the fully saturated confined aquifer were 3.5 × 10(-4) m/s, 0.2, 30 m and 60 m, respectively. The hydraulic heads as a function of time were monitored at four observation wells in the vicinity of the pit over 19 weeks and at an observation well near a test well over 21 h. In addition, by measuring the rate of pumping out from the pit sump, at a constant head (usually equal to height of the pit floor), the real inflow rates to the pit were monitored. The main innovations of this work were to make comparison between numerical modelling using a finite element software called SEEP/W and actual data related to inflow and extend the applicability of the numerical model. This model was further used to estimate the hydraulic heads at the observation wells around the pit over 19 weeks during mining operations. Data from a pump-out test and observation wells were used for model calibration and verification. In order to evaluate the model efficiency, the modelling results of inflow quantity and hydraulic heads were compared to those from analytical solutions, as well as the field data. The mean percent error in relation to field data for the inflow quantity was 0.108. It varied between 1.16 and 1.46 for hydraulic head predictions, which are much lower values than the mean percent errors resulted from the analytical solutions (from 1.8 to 5.3 for inflow and from 2.16 to 3.5 for hydraulic head predictions). The analytical solutions underestimated the inflow compared to the numerical model for the time period of 2-19 weeks. The results presented in this paper can be used for developing an effective dewatering program.

40 CFR 60.3062 - What is an air curtain incinerator?

Code of Federal Regulations, 2011 CFR

2011-07-01

... curtain of air across an open, integrated combustion chamber (fire box) or open pit or trench (trench... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What is an air curtain incinerator? 60... Rule-Air Curtain Incinerators That Burn Only Wood Waste, Clean Lumber, and Yard Waste § 60.3062 What is...

Influence of copper recovery on the water quality of the acidic Berkeley Pit lake, Montana, U.S.A.

PubMed

Tucci, Nicholas J; Gammons, Christopher H

2015-04-07

The Berkeley Pit lake in Butte, Montana, formed by flooding of an open-pit copper mine, is one of the world's largest accumulations of acidic, metal-rich water. Between 2003 and 2012, approximately 2 × 10(11) L of pit water, representing 1.3 lake volumes, were pumped from the bottom of the lake to a copper recovery plant, where dissolved Cu(2+) was precipitated on scrap iron, releasing Fe(2+) back to solution and thence back to the pit. Artificial mixing caused by this continuous pumping changed the lake from a meromictic to holomictic state, induced oxidation of dissolved Fe(2+), and caused subsequent precipitation of more than 2 × 10(8) kg of secondary ferric compounds, mainly schwertmannite and jarosite, which settled to the bottom of the lake. A large mass of As, P, and sulfate was also lost from solution. These unforeseen changes in chemistry resulted in a roughly 25-30% reduction in the lake's calculated and measured total acidity, which represents a significant potential savings in the cost of lime treatment, which is not expected to commence until 2023. Future monitoring is needed to verify that schwertmannite and jarosite in the pit sediment do not convert to goethite, a process which would release stored acidity back to the water column.

40 CFR 440.44 - New source performance standards (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... reduction attainable by the application of the best available demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines, either open pit or underground, that produce...

40 CFR 440.44 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... reduction attainable by the application of the best available demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines, either open pit or underground, that produce...

40 CFR 440.44 - New source performance standards (NSPS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... reduction attainable by the application of the best available demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines, either open pit or underground, that produce...

Adsorption of Dissolved Metals in the Berkeley Pit using Thiol-Functionalized Self-Assembled Monolayers on Mesoporous Supports (Thiol-SAMMS)

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

Betancourt, Amaury P.; Mattigod, Shas V.; Wellman, Dawn M.

2010-03-07

The Berkeley Pit in Butte, Montana, is heavily contaminated with dissolved metals. Adsorption and extraction of these metals can be accomplished through the use of a selective adsorbent. For this research, the adsorbent used was thiol-functionalized Self-Assembled Monolayers on Mesoporous Supports (thiol-SAMMS), which was developed at Pacific Northwest National Laboratory (PNNL). Thiol-SAMMS selectively binds to numerous types of dissolved metals. The objective of this research was to evaluate the loading and kinetics of aluminum, beryllium, copper, and zinc on thiol-SAMMS. For the loading tests, a series of Berkeley Pit water to thiol-SAMMS ratios (mL:g) were tested. These ratios were 1000:1,more » 500:1, 100:1, and 50:1. Berkeley Pit water is acidic (pH {approx} 2.5). This can affect the performance of SAMMS materials. Therefore, the effect of pH was evaluated by conducting parallel series of loading tests wherein the Berkeley Pit water was neutralized before or after addition of thiol-SAMMS, and a series of kinetics tests wherein the Berkeley Pit water was neutralized before addition of thiol-SAMMS for the first test and was not neutralized for the second test. For the kinetics tests, one Berkeley Pit water to thiol-SAMMS ratio was tested, which was 2000:1. The results of the loading and kinetics tests suggest that a significant decrease in dissolved metal concentration at Berkeley Pit could be realized through neutralization of Berkeley Pit water. Thiol-SAMMS technology has a limited application under the highly acidic conditions posed by the Berkeley Pit. However, thiol-SAMMS could provide a secondary remedial technique which would complete the remedial system and remove dissolved metals from the Berkeley Pit to below drinking water standards.« less

Birth Outcomes Among Military Personnel Following Exposure to Documented Open-Air Burn Pits Before and During Pregnancy

DTIC Science & Technology

2012-06-01

of the parents’ exposure to the onset of pregnancy ( maternal model) or EDC ( paternal model), cumulative days of exposure to a burn pit region before...the infant’s date of birth ( maternal model) or EDC ( paternal model), and last exposed deployment, defined as the parent’s duty location (ie, Joint Base...in Table 1. Maternal age (ie, age of the deployer in the maternal model and the deployer’s spouse in the paternal model) was lower (ន years) among

Evaluation of exposure reduction to indoor air pollution in stove intervention projects in Peru by urinary biomonitoring of polycyclic aromatic hydrocarbon metabolites.

PubMed

Li, Zheng; Sjödin, Andreas; Romanoff, Lovisa C; Horton, Kevin; Fitzgerald, Christopher L; Eppler, Adam; Aguilar-Villalobos, Manuel; Naeher, Luke P

2011-10-01

Burning biomass fuels such as wood on indoor open-pit stoves is common in developing regions. In such settings, exposure to harmful combustion products such as fine particulate matter (PM(2.5)), carbon monoxide (CO) and polycyclic aromatic hydrocarbons (PAHs) is of concern. We aimed to investigate if the replacement of open pit stoves by improved stoves equipped with a chimney would significantly reduce exposure to PAHs, PM(2.5) and CO. Two stove projects were evaluated in Peru. Program A was part of the Juntos National Program in which households built their own stoves using materials provided. In Program B, Barrick Gold Corporation hired a company to produce and install the stoves locally. A total of 30 and 27 homes participated in Program A and B, respectively. We collected personal and kitchen air samples, as well as morning urine samples from women tasked with cooking in the households before and after the installation of the improved stoves. Median levels of PM(2.5) and CO were significantly reduced in kitchen and personal air samples by 47-74% after the installation of the new stoves, while the median reduction of 10 urinary hydroxylate PAH metabolites (OH-PAHs) was 19%-52%. The observed OH-PAH concentration in this study was comparable or higher than the 95th percentile of the general U.S. population, even after the stove intervention, indicating a high overall exposure in this population. Copyright © 2011 Elsevier Ltd. All rights reserved.

Properties of hydrocarbon- and salt-contaminated flare pit soils in northeastern British Columbia (Canada).

PubMed

Arocena, J M; Rutherford, P M

2005-07-01

Many contaminated sites in Canada are associated with flare pits generated during past petroleum extraction operations. Flare pits are located adjacent to well sites, compressor stations and batteries and are often subjected to the disposal of wastes from the flaring of gas, liquid hydrocarbons and brine water. This study was conducted to evaluate the physical, chemical, electrical and mineral properties of three flare pit soils as compared to adjacent control soils. Results showed that particle size distribution, pH, total N, cation exchange capacity, exchangeable Mg(2+), and sodium adsorption ratio were similar in soils from flare pits and control sites. Total C, exchangeable Ca(2+), K(+) and Na(+), soluble Ca(2+), Mg(2+), K(+) and Na(+) and electrical conductivity were higher in flare pit soils compared to control soils. X-ray diffraction and scanning electron microscopic analyses showed the presence of gypsum [CaSO(4).2H(2)O], dolomite [CaMg(CO(3))(2)], pyrite [FeS(2)], jarosite [KFe(3)(OH)(6)(SO(4))(2)], magnesium sulphate, oxides of copper and iron+copper in salt efflorescence observed in flare pit soils. Soils from both flare pits and control sites contained mica, kaolonite and 2:1 expanding clays. The salt-rich materials altered the ionic equilibria in the flare pit soils; K(Mg-Ca) selectivity coefficients in control soils were higher compared to contaminated soils. The properties of soils (e.g., high electrical conductivity) affected by inputs associated with oil and gas operations might render flare pit soils less conducive to the establishment and growth of common agricultural crops and forest trees.

40 CFR 440.44 - New source performance standards (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

... attainable by the application of the best available demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines, either open pit or underground, that produce mercury ores...

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore... are applicable to discharges from (a) mines, either open-pit or underground, that produce mercury ores...

Open Burn Pit Registry Act of 2011

THOMAS, 112th Congress

Sen. Udall, Tom [D-NM

2011-11-03

Senate - 06/13/2012 Committee on Veterans' Affairs. Hearings held. Hearings printed: S.Hrg. 112-567. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Effects of Laser Etching on the Corrosion Susceptibility of SAVY 4000 and Hagan Containers

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

Hyer, Holden Christopher; Duque, Juan; Smith, Paul Herrick

Since the late 1990’s, the Hagan container was used as the primary container for packaging of plutonium-bearing materials. The Hagan design consisted of a threaded closure, a Viton® ORing, a carbon-carbon filter, and a 304L stainless steel (SS) body. Over the years, Hagans have shown vulnerability in their design [1]. In 2008, The Department of Energy (DOE) issued DOE M 441.1-1, Nuclear Material Packaging Manual, which detailed an approach to obtain highconfidence in containers by including specific design requirements, material contents and an approach to determine life span from said contents, and surveillance techniques [2]. In response to both themore » vulnerability issues with the Hagan and DOE M 441.1-1, the SAVY 4000 container with its twist style closure, Viton® O-Ring, Fiberfrax-Gortex filter, and annealed 316L SS body, was designed as the replacement for Hagan containers, but only for a short term lifespan of 5 years [1]. However, both the Hagan and SAVY 4000 are being pushed to maintain a lifespan of 40 years. Therefore, proper confidence must be placed on each component of each container to last a minimum of 40 years. So far, the biggest concern found during surveillance of these containers is corrosion and the potential for failure by corrosion. One concern is that the containers fail due to stress corrosion cracking (SCC), especially around the weld between the collar and the body as welds leave residual stresses. One advantage the SAVY 4000 has is that the body is annealed, but its weld is still susceptible as it was welded after annealing [3, 4]. Moreover, 316L SS is known to have a higher pitting resistance (pits are a precursor to SCC and can also lead to extensive failure of the material), than 304L SS [4]. During recent surveillance activities, two SAVY 4000’s containing Solution Assay Instrument (SAI) solutions were opened. The SAI SAVY 4000’s contained plutonium (Pu) in 3M HCl solution in plastic volumetric flasks placed inside of polyethylene bags. Historically, a SAVY 4000 containing an SAI solution is packaged for 3 weeks, however, these particular containers were not reopened until 14 months later. When opened, brown-red corrosion product was found all over the inside of the container as shown in Figure 1.« less

Blasting methods for heterogeneous rocks in hillside open-pit mines with high and steep slopes

NASA Astrophysics Data System (ADS)

Chen, Y. J.; Chang, Z. G.; Chao, X. H.; Zhao, J. F.

2017-06-01

In the arid desert areas in Xinjiang, most limestone quarries are hillside open-pit mines (OPMs) where the limestone is hard, heterogeneous, and fractured, and can be easily broken into large blocks by blasting. This study tried to find effective technical methods for blasting heterogeneous rocks in such quarries based on an investigation into existing problems encountered in actual mining at Hongshun Limestone Quarry in Xinjiang. This study provided blasting schemes for hillside OPMs with different heights and slopes. These schemes involve the use of vertical deep holes, oblique shallow holes, and downslope hole-by-hole sublevel or simultaneous detonation techniques. In each bench, the detonations of holes in a detonation unit occur at intervals of 25-50 milliseconds. The research findings can offer technical guidance on how to blast heterogeneous rocks in hillside limestone quarries.

The Study Of Soil And Agrochemical Features Of Zonal Soils Of Coal Mining Enterprises In Kemerovo Region

NASA Astrophysics Data System (ADS)

Yakovchenko, M. A.; Kosolapova, A. A.; Ermolaev, V. A.

2017-01-01

The paper represents the results of the study of soil and agrochemical features of zonal soils: the grain-size composition, the content of humus, phosphorus and potassium, and heavy metals, the reaction of soil solution of the territory of the open-pit coal mine No12 of Kemerovo region in the areas of the working enterprise. The species composition of the lignose and herbaceous vegetation of the undisturbed territories has been studied. It has been revealed that the fertile soil layer of the studied areas of the open-pit coal mine is characterized as fertile but can’t be removed and stored because the surface of the whole area under study is forest-covered very much, rumpled, there are gullies and a lot of wind-fallen trees.

Volume Computation of a Stockpile - a Study Case Comparing GPS and Uav Measurements in AN Open Pit Quarry

NASA Astrophysics Data System (ADS)

Raeva, P. L.; Filipova, S. L.; Filipov, D. G.

2016-06-01

The following paper aims to test and evaluate the accuracy of UAV data for volumetric measurements to the conventional GNSS techniques. For this purpose, an appropriate open pit quarry has been chosen. Two sets of measurements were performed. Firstly, a stockpile was measured by GNSS technologies and later other terrestrial GNSS measurements for modelling the berms of the quarry were taken. Secondly, the area of the whole quarry including the stockpile site was mapped by a UAV flight. Having considered how dynamic our world is, new techniques and methods should be presented in numerous fields. For instance, the management of an open pit quarry requires gaining, processing and storing a large amount of information which is constantly changing with time. Fast and precise acquisition of measurements regarding the process taking place in a quarry is the key to an effective and stable maintenance. In other words, this means getting an objective evaluations of the processes, using up-to-date technologies and reliable accuracy of the results. Often legislations concerning mine engineering state that the volumetric calculations are to present ±3% accuracy of the whole amount. On one hand, extremely precise measurements could be performed by GNSS technologies, however, it could be really time consuming. On the other hand, UAV photogrammetry presents a fast, accurate method for mapping large areas and calculating stockpiles volumes. The study case was performed as a part of a master thesis.

21 CFR 145.185 - Canned plums.

Code of Federal Regulations, 2012 CFR

2012-04-01

... “golden” or “red” or “purple”, as appropriate, or the specific name of the variety or “Greengage plums... tree or other harmless extraneous plant material per 200 grams (7 ounces) of drained plums. (v) Loose pits in whole style. Not more than three loose pits per 500 grams (17.6 ounces) of drained plums. (vi...

21 CFR 145.185 - Canned plums.

Code of Federal Regulations, 2013 CFR

2013-04-01

... “golden” or “red” or “purple”, as appropriate, or the specific name of the variety or “Greengage plums... tree or other harmless extraneous plant material per 200 grams (7 ounces) of drained plums. (v) Loose pits in whole style. Not more than three loose pits per 500 grams (17.6 ounces) of drained plums. (vi...

21 CFR 145.185 - Canned plums.

Code of Federal Regulations, 2014 CFR

2014-04-01

... “golden” or “red” or “purple”, as appropriate, or the specific name of the variety or “Greengage plums... tree or other harmless extraneous plant material per 200 grams (7 ounces) of drained plums. (v) Loose pits in whole style. Not more than three loose pits per 500 grams (17.6 ounces) of drained plums. (vi...

21 CFR 145.185 - Canned plums.

Code of Federal Regulations, 2011 CFR

2011-04-01

... “golden” or “red” or “purple”, as appropriate, or the specific name of the variety or “Greengage plums... tree or other harmless extraneous plant material per 200 grams (7 ounces) of drained plums. (v) Loose pits in whole style. Not more than three loose pits per 500 grams (17.6 ounces) of drained plums. (vi...

Long term monitoring of water basin of an abandoned copper open pit mine

NASA Astrophysics Data System (ADS)

Nikolov, H.; Borisova, D.

2012-04-01

Nonoperating open pit mines, very often as a matter of fact abandoned, create serious ecological risk for the region of their location especially for the quality of the water since the rainfall fills the bottom of the pit forming water body having different depth. This water as a rule has very high concentration of the metals in it and is highly toxic. One example for such opencast, idle copper mine is Medet located in the central part of Bulgaria who was started for exploitation in 1964 and at that moment being the largest in Europe for production of copper concentrate. In the vicinity of it after autumn and spring rains there are many cases reported for water contamination by heavy metals such as arsenic, copper, cadmium in the rivers running close to this open pit mine. This justifies the need for long term and sustainable monitoring of the area of the water basin of this idle mine in order to estimate its acid drainage and imaging spectroscopy combined with is-situ investigations is proved to provide reliable results about the area of the water table. In the course of this study we have investigated historical data gathered by remote sensing which allowed us to make conclusions about the year behavior of this area. Our expectations are that the results of this research will help in the rehabilitation process of this idle mine and will provide the local authorities engaged in water quality monitoring with a tool to estimate the possible damage caused to the local rivers and springs. With this research we also would like to contribute to the fulfillment of the following EU Directives: Directive 2006/21/°C on the Management of Waste from the Extractive Industries and Directive 2004/35/ °C on Environmental Liability with regard to the Prevention and Remedying of Environmental Damage.

Measurements of evaporation from a mine void lake and testing of modelling approaches

NASA Astrophysics Data System (ADS)

McJannet, David; Hawdon, Aaron; Van Niel, Tom; Boadle, Dave; Baker, Brett; Trefry, Mike; Rea, Iain

2017-12-01

Pit lakes often form in the void that remains after open cut mining operations cease. As pit lakes fill, hydrological and geochemical processes interact and these need to be understood for appropriate management actions to be implemented. Evaporation is important in the evolution of pit lakes as it acts to concentrate various constituents, controls water level and changes the thermal characteristics of the water body. Despite its importance, evaporation from pit lakes is poorly understood. To address this, we used an automated floating evaporation pan and undertook measurements at a pit lake over a 12 month period. We also developed a new procedure for correcting floating pan evaporation estimates to lake evaporation estimates based on surface temperature differences. Total annual evaporation was 2690 mm and reflected the strong radiation inputs, high temperatures and low humidity experienced in this region. Measurements were used to test the performance of evaporation estimates derived using both pan coefficient and aerodynamic modelling techniques. Daily and monthly evaporation estimates were poorly reproduced using pan coefficient techniques and their use is not recommended for such environments. Aerodynamic modelling was undertaken using a range of input datasets that may be available to those who manage pit lake systems. Excellent model performance was achieved using over-water or local over-land meteorological observations, particularly when the sheltering effects of the pit were considered. Model performance was reduced when off-site data were utilised and differences between local and off-site vapor pressure and wind speed were found to be the major cause.

Hephaestus Fossae

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site] (Released 3 July 2002) Off the western flank of Elysium are the Hephaestus Fossae, including linear arrangements of small, round pits. These features are commonly called 'pit chains' and most likely represent the collapse of lava tubes. Lava tubes allow molten rock to move long distances underground. When the lava drains out it leaves unsupported tunnels, which can collapse and form pits. These particular pit chains are unusual because they change direction abruptly. In the lower portion of the image, pits have collapsed at the bends and allow us to observe the sharp, nearly right angle corners. These direction changes are most likely due to some sort of structural control during the emplacement of the lava tubes. There is an extraordinarily high concentration of small, degraded craters on the plains surface. The size range of these craters is fairly consistent and they all appear to be of similar age. It is unlikely that these were caused by primary impacts (impacts of meteors onto the surface) because both the size and timing distributions of primary impactors vary tremendously. However, the craters in the image could have been created from secondary impacts. Secondaries are impacts of material that is excavated during a large cratering event nearby or from the disintegration of a primary meteor in the atmosphere into many smaller parts that rain onto the surface. In contrast to these older, small craters, there is a relatively young crater in the center of the image. A hummocky ejecta blanket is visible around the crater and has covered some of the smaller craters on the plain around it. The edges of the crater are sharp, formed by rocky material in the crater rim. This material is visible as the layer of rough, grooved material at the top of the inside walls. Small dust avalanches have left dark streaks down the inside walls of the crater.

Geochemical evolution of a high arsenic, alkaline pit-lake in the Mother Lode Gold District, California

USGS Publications Warehouse

Savage, Kaye S.; Ashley, Roger P.; Bird, Dennis K.

2009-01-01

The Harvard orebody at the Jamestown gold mine, located along the Melones fault zone in the southern Mother Lode gold district, California, was mined in an open-pit operation from 1987 to 1994. Dewatering during mining produced a hydrologic cone of depression; recovery toward the premining ground-water configuration produced a monomictic pit lake with alkaline Ca-Mg-HCO3-SO4–type pit water, concentrations of As up to 1,200 μg/L, and total dissolved solids (TDS) up to 2,000 mg/L. In this study, pit-wall rocks were mapped and chemically analyzed to provide a context for evaluating observed variability in the composition of the pit-lake waters in relationship to seasonal weather patterns. An integrated hydrogeochemical model of pit-lake evolution based on observations of pit-lake volume, water composition (samples collected between 1998–2000, 2004), and processes occurring on pit walls was developed in three stages using the computer code PHREEQC. Stage 1 takes account of seasonally variable water fluxes from precipitation, evaporation, springs, and ground water, as well as lake stratification and mixing processes. Stage 2 adds CO2fluxes and wall-rock interactions, and stage 3 assesses the predictive capability of the model.Two major geologic units in fault contact comprise the pit walls. The hanging wall is composed of interlayered slate, metavolcanic and metavolcaniclastic rocks, and schists; the footwall rocks are chlorite-actinolite and talc-tremolite schists generated by metasomatism of greenschist-facies mafic and ultramafic igneous rocks. Alteration in the ore zone provides evidence for mineralizing fluids that introduced CO2, S, and K2O, and redistributed SiO2. Arsenian pyrite associated with the alteration weathers to produce goethite and jarosite on pit walls and in joints, as well as copiapite and hexahydrite efflorescences that accumulate on wall-rock faces during dry California summers. All of these pyrite weathering products incorporate arsenic at concentrations from <100 up to 1,200 ppm. In the pit lake, pH and TDS reach seasonal highs in the summer epilimnion; pH is lowest in the summer hypolimnion. Arsenic and bicarbonate covary in the hypolimnion, rising as stratification proceeds and declining during winter rains. The computational model suggests that water fluxes alone do not account for this seasonal variability. Loss of CO2 to the atmosphere, interaction with pit walls including washoff of efflorescent salts during the first flush and seasonal rainfall, and arsenic sorption appear to contribute to the observed pit-lake characteristics.

Paleo-Environment and C-14 Dating: The Key to the Depositional Age of the Tha Chang and Related Sand Pits, Northeastern Thailand

NASA Technical Reports Server (NTRS)

Putthapiban, P.; Zolensky, M.; Jull, T.; Demartino, M.; Salyapongse, S.

2012-01-01

Tha Chang sand pits, Nakhon Ratchasima Province and many other sand pits in the area adjacent to the Mun River are characterized by their fluviatile environment in association with mass wasting deposits, along the paleo-river channel and the flood plain of the Mun River. Sediments of these deposits are characterized by clasts of various rock types especially the resistant ones with frequent big tree trunks, logs and wood fragments in different sizes and various stages of transformation from moldering stage to lignification and petrification. Widespread pyritization of the lower horizon suggests strongly reducing environment during burial. The Tha Chang deposits have been received much attention from geoscientists especially paleontologist communities, as they contain fragments of some distinct vertebrate species such as Stegadon sp., hominoid primate, rhinoceros Aceratherium and others. Based on the associated mammal fauna and hominoid fossils, the late Miocene ( 9 - 6 Ma) was given for the time of deposition of this sand and gravel unit. Some other reports believed that sediments and materials of these sand and gravel quarries (pits) were deposited by high-energy flood pulses contemporaneous with the tektites forming event during mid-Pleistocene at c. 0.8 Ma. Interpretation from Palynostratigraphical study suggested that the lower horizon of Tha Chang sand pit was deposited during Pliocene/Pleistocene period and the upper horizons are Pleistoncene/Holocene. It is crystal clear that all the fluviatile sediments including tektites and almost all fossil fragments being deposited in these sand pits were, likely a multiple times reworked materials. Only some old bamboo trees, some old crowling trees and fossils grasses observed on the old river bank are considered in situ. C-14 dating of 5 old wood specimens from Tha Chang Sand Pits, 15 old wood specimens from Chumpuang Sand Pits and one sample of old pottery from a Chumpuang Sand Pit were carried out in the NSF- Arizona AMS Laboratory. Although, there is no sharp boundary between the unconsolidated sedimentary horizons in the pits, C-14 ages obtained from the Tha Chang vary from 34,340 BP at the middle horizon (approx 10 m below ground zero) to >49,900 BP at the lower horizon with unknown basal formation (highly pyritized zone approx 20 - 25 m below ground zero). The ages for the Chumpuang vary from 41,700 BP, >45,900 BP and >49,900 BP from the upper most to the lower most of a broad horizon (approx 8 m to approx 12 m below ground zero). The C-14 age of the pottery collected from layer approximately 5 m below ground zero is 2,514 BP. The nature of fluviatile together with occasional mass wasting characteristics of all sand pits studies suggest the relatively faster depositional rate of the lower horizon which involved more flooding and mass wasting deposits than those of the upper horizons. The apparent of some mixing of the wood ages may indicate reworking and lag deposits nature of the area. The depositional rate of the upper most sand and soil horizon (5 m thick) is approximately 1 m per 500 years which mean both erosion and deposition had played a significant role during that time period. In term of the true age of the formation, we argue that since most of the materials deposited are reworked materials, all ages obtained from fossil fragments could not be the age of sand and gravel formation. Furthermore, the maximum age of all the tektite bearing horizons cannot be older than 0.8 Ma. The oldest C-14 age of 49,900 BP is interpreted as the minimum age of the Tha Chang and related sand pits formation when geomorphology of the area was a lot more hilly and much higher gradient than that of the present day.

High quality InP-on-Si for solar cell applications

NASA Technical Reports Server (NTRS)

Shellenbarger, Zane A.; Goodwin, Thomas A.; Collins, Sandra R.; Dinetta, Louis C.

1994-01-01

InP on Si solar cells combine the low-cost and high-strength of Si with the high efficiency and radiation tolerance of InP. The main obstacle in the growth of single crystal InP-on-Si is the high residual strain and high dislocation density of the heteroepitaxial InP films. The dislocations result from the large differences in lattice constant and thermal expansion mismatch of InP and Si. Adjusting the size and geometry of the growth area is one possible method of addressing this problem. In this work, we conducted a material quality study of liquid phase epitaxy overgrowth layers on selective area InP grown by a proprietary vapor phase epitaxy technique on Si. The relationship between growth area and dislocation density was quantified using etch pit density measurements. Material quality of the InP on Si improved both with reduced growth area and increased aspect ratio (length/width) of the selective area. Areas with etch pit density as low as 1.6 x 10(exp 4) sq cm were obtained. Assuming dislocation density is an order of magnitude greater than etch pit density, solar cells made with this material could achieve the maximum theoretical efficiency of 23% at AMO. Etch pit density dependence on the orientation of the selective areas on the substrate was also studied.

Osteoclasts on bone and dentin in vitro: mechanism of trail formation and comparison of resorption behavior.

PubMed

Rumpler, M; Würger, T; Roschger, P; Zwettler, E; Sturmlechner, I; Altmann, P; Fratzl, P; Rogers, M J; Klaushofer, K

2013-12-01

The main function of osteoclasts in vivo is the resorption of bone matrix, leaving behind typical resorption traces consisting of pits and trails. The mechanism of pit formation is well described, but less is known about trail formation. Pit-forming osteoclasts possess round actin rings. In this study we show that trail-forming osteoclasts have crescent-shaped actin rings and provide a model that describes the detailed mechanism. To generate a trail, the actin ring of the resorption organelle attaches with one side outside the existing trail margin. The other side of the ring attaches to the wall inside the trail, thus sealing that narrow part to be resorbed next (3–21 lm). This 3D configuration allows vertical resorption layer-by-layer from the surface to a depth in combination with horizontal cell movement. Thus, trails are not just traces of a horizontal translation of osteoclasts during resorption. Additionally, we compared osteoclastic resorption on bone and dentin since the latter is the most frequently used in vitro model and data are extrapolated to bone. Histomorphometric analyses revealed a material-dependent effect reflected by an 11-fold higher resorption area and a sevenfold higher number of pits per square centimeter on dentin compared to bone. An important material-independent aspect was reflected by comparable mean pit area (μm²) and podosome patterns. Hence, dentin promotes the generation of resorbing osteoclasts, but once resorption has started, it proceeds independently of material properties. Thus, dentin is a suitable model substrate for data acquisition as long as osteoclast generation is not part of the analyses.

Three-dimensional non-destructive optical evaluation of laser-processing performance using optical coherence tomography.

PubMed

Kim, Youngseop; Choi, Eun Seo; Kwak, Wooseop; Shin, Yongjin; Jung, Woonggyu; Ahn, Yeh-Chan; Chen, Zhongping

2008-06-01

We demonstrate the use of optical coherence tomography (OCT) as a non-destructive diagnostic tool for evaluating laser-processing performance by imaging the features of a pit and a rim. A pit formed on a material at different laser-processing conditions is imaged using both a conventional scanning electron microscope (SEM) and OCT. Then using corresponding images, the geometrical characteristics of the pit are analyzed and compared. From the results, we could verify the feasibility and the potential of the application of OCT to the monitoring of the laser-processing performance.

Three-dimensional non-destructive optical evaluation of laser-processing performance using optical coherence tomography

PubMed Central

Kim, Youngseop; Choi, Eun Seo; Kwak, Wooseop; Shin, Yongjin; Jung, Woonggyu; Ahn, Yeh-Chan; Chen, Zhongping

2014-01-01

We demonstrate the use of optical coherence tomography (OCT) as a non-destructive diagnostic tool for evaluating laser-processing performance by imaging the features of a pit and a rim. A pit formed on a material at different laser-processing conditions is imaged using both a conventional scanning electron microscope (SEM) and OCT. Then using corresponding images, the geometrical characteristics of the pit are analyzed and compared. From the results, we could verify the feasibility and the potential of the application of OCT to the monitoring of the laser-processing performance. PMID:24932051

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

Fisher, L.M.

Presently some methods of HTS-conductors processing are under study in the authors laboratory. ``Powder-in-tube`` (PIT), ``Jelly-roll``, electrophorethis are among them. PIT process has developed predominantly both in a view of the achieved J{sub c} values Bi-2223 phase was used as a core material for these tapes. Since the main purpose of the task order was to enhance the development of long length high temperature superconductor tapes, the authors have considered reasonable to lay the perfection idea of the PIT process step by step or tape by tape. To realize it they have assumed, keeping stable the basic scheme of PITmore » process, to vary some technological parameters which are as follows: (1) type of initial powder; (2) sheath material; (3) tape construction (filaments number, cross section e.a.); and (4) processing regimes. This report covers the fabrication process and characteristics of the produced conductors.« less

Characterization and comparison of emissions from rudimentary waste disposal technologies

EPA Science Inventory

Results from 2011 simulation of burn pit emissions and air curtain incinerator emissions, recent developments in methods for open air sampling, comparison of waste energy technologies, current SERDP programs in this area.

Introduction to Pits and Weapons Systems (U)

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

Kautz, D.

2012-07-02

A Nuclear Explosive Package includes the Primary, Secondary, Radiation Case and related components. This is the part of the weapon that produces nuclear yield and it converts mechanical energy into nuclear energy. The pit is composed of materials that allow mechanical energy to be converted to electromagnetic energy. Fabrication processes used are typical of any metal fabrication facility: casting, forming, machining and welding. Some of the materials used in pits include: Plutonium, Uranium, Stainless Steel, Beryllium, Titanium, and Aluminum. Gloveboxes are used for three reasons: (1) Protect workers and public from easily transported, finely divided plutonium oxides - (a) Plutoniummore » is very reactive and produces very fine particulate oxides, (b) While not the 'Most dangerous material in the world' of Manhattan Project lore, plutonium is hazardous to health of workers if not properly controlled; (2) Protect plutonium from reactive materials - (a) Plutonium is extremely reactive at ambient conditions with several components found in air: oxygen, water, hydrogen, (b) As with most reactive metals, reactions with these materials may be violent and difficult to control, (c) As with most fabricated metal products, corrosion may significantly affect the mechanical, chemical, and physical properties of the product; and (3) Provide shielding from radioactive decay products: {alpha}, {gamma}, and {eta} are commonly associated with plutonium decay, as well as highly radioactive materials such as {sup 241}Am and {sup 238}Pu.« less

Simulations and measurements of artificial cracks and pits in flat stainless steel plates using tone burst eddy-current thermography (TBET)

NASA Astrophysics Data System (ADS)

Libin, M. N.; Balasubramaniam, Krishnan; Maxfield, B. W.; Krishnamurthy, C. V.

2013-01-01

Tone Burst Eddy current Thermography (TBET) is a new hybrid, non-contacting, Non-Destructive Evaluation (NDE) method which employs a combination of Pulsed Eddy current Thermography (PEC) and Thermographic Non-Destructive Evaluation (TNDE). For understanding the influence of cracking and pitting on heat generation and flow within a metallic body, a fundamental knowledge of the detailed induced current density distribution in the component under test is required. This information enables us to calculate the amount of heat produced by the defects and how that heat diffuses to the surface where it is imaged. This paper describes simulation work done for artificial pits and cracks within pits on the far surface of poorly conducting metals like stainless steel. The first phase of this investigation simulates the transient thermal distribution for artificial 2D pit and crack-like defects using the finite element package COMSOL multi-physics with the AC/DC module and general heat transfer. Considering the reflection measurement geometry where thermal excitation and temperature monitoring are on the same surface, pitting reduces the material volume thereby contributing to a larger temperature rise for the same thermal energy input. A crack within a pit gives a further increase in temperature above the pure pit baseline. The tone burst frequency can be changed to obtain approximately uniform heating (low frequency) or heating of a thin region at the observation surface. Although front surface temperature changes due to 10% deep far-side pits in a 6 mm thick plate can be measured, it is not yet clear whether a 20% deep crack within this pit can be discriminated against the background. Both simulations and measurements will be presented. The objective of this work is to determine whether the TBET method is suitable for the detection and characterization of far side pitting, cracking and cracks within those pits.

Chemical etching of stainless steel 301 for improving performance of electrochemical capacitors in aqueous electrolyte

NASA Astrophysics Data System (ADS)

Jeżowski, P.; Nowicki, M.; Grzeszkowiak, M.; Czajka, R.; Béguin, F.

2015-04-01

The main purpose of the study was to increase the surface roughness of stainless steel 301 current collectors by etching, in order to improve the electrochemical performance of electrical double-layer capacitors (EDLC) in 1 mol L-1 lithium sulphate electrolyte. Etching was realized in 1:3:30 (HNO3:HCl:H2O) solution with times varying up to 10 min. For the considered 15 μm thick foil and a mass loss around 0.4 wt.%, pitting was uniform, with diameter of pits ranging from 100 to 300 nm. Atomic force microscopy (AFM) showed an increase of average surface roughness (Ra) from 5 nm for the as-received stainless steel foil to 24 nm for the pitted material. Electrochemical impedance spectroscopy realized on EDLCs with coated electrodes either on as-received or pitted foil in 1 mol L-1 Li2SO4 gave equivalent distributed resistance (EDR) of 8 Ω and 2 Ω, respectively, demonstrating a substantial improvement of collector/electrode interface after pitting. Correlatively, the EDLCs with pitted collector displayed a better charge propagation and low ohmic losses even at relatively high current of 20 A g-1. Hence, chemical pitting of stainless steel current collectors is an appropriate method for optimising the performance of EDLCs in neutral aqueous electrolyte.

Contamination of the cement raw material in a quarry site by seawater intrusion, Darica-Turkey

NASA Astrophysics Data System (ADS)

Camur, M. Zeki; Doyuran, Vedat

2008-02-01

The open pit mining nearby shoreline is planned to be extended into below sea level in order to use additional reserves of the cement raw material (marl). The raw material is currently contaminated by seawater intrusion below a depth of 20 m up to the distance of 90 m from shoreline. Seawater intrusion related contamination of the material used for the cement production was investigated by means of diffusion process for the future two below sea level mining scenarios covering 43 years of period. According to the results, chloride concentrations higher than the tolerable limit of a cement raw material would be present in the material about 10-25 cm inward from each discontinuity surface, controlling groundwater flow, located between 170 and 300 m landward from the shoreline at below sea level mining depths of 0-30 m. The estimations suggest that total amounts of dilution required for the contaminated raw material to reduce its concentration level to the tolerance limit with uncontaminated raw material are about 113- to 124-fold for scenario I (13 years of below sea level mining after 30 years of above sea level mining) and about 126- to 138-fold for scenario II (43 years of simultaneous above and below sea level minings).

Characterization of erosion of metallic materials under cavitation attack in a mineral oil

NASA Technical Reports Server (NTRS)

Rao, B. C. S.; Buckley, D. H.

1984-01-01

Cavitation erosion and erosion rates of eight metallic materials representing three crystal structures were studied using a 20-kHz ultrasonic magnetostrictive oscillator in viscous mineral oil. The erosion rates of the metals with an fcc matrix were 10 to 100 times higher than that of an hcp-matrix titanium alloy. The erosion rates of iron and molybdenum, with bcc matrices, were higher than that of the titanium alloy but lower than those of the fcc metals. Scanning electron microscopy indicates that the cavitation pits are initially formed at the grain boundaries and precipitates and that the pits that formed at the triple points grew faster than the others. Transcrystalline craters formed by cavitation attack over the surface of grains and roughened the surfaces by multiple slip and twinning. Surface roughness measurements show that the pits that formed over the grain boundaries deepended faster than other pits. Computer analysis revealed that a geometric expression describes the nondimensional erosion curves during the time period 0.5 t(0) t 2.5 t(0), where t(0) is the incubation period. The fcc metals had very short incubation periods; the titanium alloy had the longest incubation period.

Pits in Polar Cap

NASA Technical Reports Server (NTRS)

2006-01-01

This full-frame image from the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter shows faults and pits in Mars' north polar residual cap that have not been previously recognized.

The faults and depressions between them are similar to features seen on Earth where the crust is being pulled apart. Such tectonic extension must have occurred very recently because the north polar residual cap is very young, as indicated by the paucity of impact craters on its surface. Alternatively, the faults and pits may be caused by collapse due to removal of material beneath the surface. The pits are aligned along the faults, either because material has drained into the subsurface along the faults or because gas has escaped from the subsurface through them.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

Construction risk assessment of deep foundation pit in metro station based on G-COWA method

NASA Astrophysics Data System (ADS)

You, Weibao; Wang, Jianbo; Zhang, Wei; Liu, Fangmeng; Yang, Diying

2018-05-01

In order to get an accurate understanding of the construction safety of deep foundation pit in metro station and reduce the probability and loss of risk occurrence, a risk assessment method based on G-COWA is proposed. Firstly, relying on the specific engineering examples and the construction characteristics of deep foundation pit, an evaluation index system based on the five factors of “human, management, technology, material and environment” is established. Secondly, the C-OWA operator is introduced to realize the evaluation index empowerment and weaken the negative influence of expert subjective preference. The gray cluster analysis and fuzzy comprehensive evaluation method are combined to construct the construction risk assessment model of deep foundation pit, which can effectively solve the uncertainties. Finally, the model is applied to the actual project of deep foundation pit of Qingdao Metro North Station, determine its construction risk rating is “medium”, evaluate the model is feasible and reasonable. And then corresponding control measures are put forward and useful reference are provided.

Volume Measurements of Laser-generated Pits for In Situ Geochronology using KArLE (Potassium-Argon Laser Experiment)

NASA Technical Reports Server (NTRS)

French, R. A.; Cohen, B. A.; Miller, J. S.

2014-01-01

The Potassium-Argon Laser Experiment( KArLE), is composed of two main instruments: a spectrometer as part of the Laser-Induced Breakdown Spectroscopy (LIBS) method and a Mass Spectrometer (MS). The LIBS laser ablates a sample and creates a plasma cloud, generating a pit in the sample. The LIBS plasma is measured for K abundance in weight percent and the released gas is measured using the MS, which calculates Ar abundance in mols. To relate the K and Ar measurements, total mass of the ablated sample is needed but can be difficult to directly measure. Instead, density and volume are used to calculate mass, where density is calculated based on the elemental composition of the rock (from the emission spectrum) and volume is determined by pit morphology. This study aims to reduce the uncertainty for KArLE by analyzing pit volume relationships in several analog materials and comparing methods of pit volume measurements and their associated uncertainties.

Nuts, nut cracking, and pitted stones at Gesher Benot Ya‘aqov, Israel

PubMed Central

Goren-Inbar, Naama; Sharon, Gonen; Melamed, Yoel; Kislev, Mordechai

2002-01-01

The Acheulian site of Gesher Benot Ya‘aqov (Israel) has revealed a unique association of edible nuts with pitted hammers and anvils. Located in the Dead Sea rift, on the boundary between the Arabian and African plates, the site dates to the Early-Middle Pleistocene, oxygen isotope stage 19. In a series of strata, seven species of nuts, most of which can be cracked open only by a hard hammer, were uncovered. Five of the species are extant terrestrial nuts, and two are aquatic nuts now extinct in the Levant. In addition, the site yielded an assemblage of pitted hammers and anvils similar in pit morphology to those used by chimpanzees and contemporary hunter–gatherers. This is the first time, to our knowledge, that a site has offered both paleobotanical and lithic evidence of plant foods eaten by early hominins and technologies used for processing these foods. The evidence also sheds light on the structure of the community: ethnographic analogies suggest that mixedgender groups may have been active on the shores of paleoLake Hula. PMID:11854536

The Western Environmental Technology Office (WETO), Butte, Montana. Technology summary

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

NONE

1996-03-01

The Western Environmental Technology Office (WETO) is a multi-purpose engineering test facility located in Butte, Montana, and is managed by MSE, Inc. WETO seeks to contribute to environmental research by emphasizing projects to develop heavy metals removal and recovery processes, thermal vitrification systems, and waste minimization/pollution prevention technologies. WETO`s environmental technology research and testing activities focus on the recovery of usable resources from waste. In one of WETO`s areas of focus, groundwater contamination, water from the Berkeley Pit, located near the WETO site, is being used in demonstrations directed toward the recovery of potable water and metal from the heavymore » metal-bearing water. The Berkeley Pit is part of an inactive copper mine near Butte that was once part of the nation`s largest open-pit mining operation. The Pit contains approximately 25 billion gallons of Berkeley Pit groundwater and surface water containing many dissolved minerals. As part of DOE/OST`s Resource Recovery Project (RRP), technologies are being demonstrated to not only clean the contaminated water but to recover metal values such as copper, zinc, and iron with an estimated gross value of more than $100 million. When recovered, the Berkeley Pit waters could benefit the entire Butte valley with new water resources for fisheries, irrigation, municipal, and industrial use. At WETO, the emphasis is on environmental technology development and commercialization activities, which will focus on mine cleanup, waste treatment, resource recovery, and water resource management.« less

Arne - Exploring the Mare Tranquillitatis Pit

NASA Astrophysics Data System (ADS)

Robinson, M. S.; Thangavelautham, J.; Wagner, R.; Hernandez, V. A.; Finch, J.

2014-12-01

Lunar mare "pits" are key science and exploration targets. The first three pits were discovered within Selene observations [1,2] and were proposed to represent collapses into lava tubes. Subsequent LROC images revealed 5 new mare pits and showed that the Mare Tranquillitatis pit (MTP; 8.335°N, 33.222°E) opens into a sublunarean void at least 20-meters in extent [3,4]. A key remaining task is determining pit subsurface extents, and thus fully understanding their exploration and scientific value. We propose a simple and cost effective reconnaissance of the MTP using a small lander (<130 kg) named Arne, that carries three flying microbots (or pit-bots) [5,6,7]. Key measurement objectives include decimeter scale characterization of the pit walls, 5-cm scale imaging of the eastern floor, determination of the extent of sublunarean void(s), and measurement of the magnetic and thermal environment. After landing and initial surface systems check Arne will transmit full resolution descent and surface images. Within two hours the first pit-bot will launch and fly into the eastern void. Depending on results from the first pit-bot the second and third will launch and perform follow-up observations. The primary mission is expected to last 48-hours; before the Sun sets on the lander there should be enough time to execute ten flights with each pit-bot. The pit-bots are 30-cm diameter spherical flying robots [5,6,7] equipped with stereo cameras, temperature sensors, sensors for obstacle avoidance and a laser rangefinder. Lithium hydride [5,6] and water/hydrogen peroxide power three micro-thrusters and achieve a specific impulse of 350-400 s. Each pit-bot can fly for 2 min at 2 m/s for more than 100 cycles; recharge time is 20 min. Arne will carry a magnetometer, thermometer, 2 high resolution cameras, and 6 wide angle cameras and obstacle avoidance infrared sensors enabling detailed characterization of extant sublunarean voids. [1] Haruyama et al. (2010) 41st LPSC, #1285. [2] Haruyama et al. (2010) GRL, 36, dx.doi.org/ 10.1029/2009GL0406355. [3] Robinson et al (2012) PSS, 69, dx.doi.org/ 10.1016/j.pss.2012.05.008 [4] Wagner and Robinson (2014) Icarus, dx.doi.org/10.1016/j.icarus.2014.04.002. [5] Thangavelautham et al. (2012) IEEE ICRA [6] Strawser et al. (2014) J. Hydrogen Energy. [7] Dubowsky et al. (2007) Proc. CLAWAR.

Characterizing Hypervelocity Impact (HVI)-Induced Pitting Damage Using Active Guided Ultrasonic Waves: From Linear to Nonlinear

PubMed Central

Liu, Menglong; Wang, Kai; Lissenden, Cliff J.; Wang, Qiang; Zhang, Qingming; Long, Renrong; Su, Zhongqing; Cui, Fangsen

2017-01-01

Hypervelocity impact (HVI), ubiquitous in low Earth orbit with an impacting velocity in excess of 1 km/s, poses an immense threat to the safety of orbiting spacecraft. Upon penetration of the outer shielding layer of a typical two-layer shielding system, the shattered projectile, together with the jetted materials of the outer shielding material, subsequently impinge the inner shielding layer, to which pitting damage is introduced. The pitting damage includes numerous craters and cracks disorderedly scattered over a wide region. Targeting the quantitative evaluation of this sort of damage (multitudinous damage within a singular inspection region), a characterization strategy, associating linear with nonlinear features of guided ultrasonic waves, is developed. Linear-wise, changes in the signal features in the time domain (e.g., time-of-flight and energy dissipation) are extracted, for detecting gross damage whose characteristic dimensions are comparable to the wavelength of the probing wave; nonlinear-wise, changes in the signal features in the frequency domain (e.g., second harmonic generation), which are proven to be more sensitive than their linear counterparts to small-scale damage, are explored to characterize HVI-induced pitting damage scattered in the inner layer. A numerical simulation, supplemented with experimental validation, quantitatively reveals the accumulation of nonlinearity of the guided waves when the waves traverse the pitting damage, based on which linear and nonlinear damage indices are proposed. A path-based rapid imaging algorithm, in conjunction with the use of the developed linear and nonlinear indices, is developed, whereby the HVI-induced pitting damage is characterized in images in terms of the probability of occurrence. PMID:28772908

Limitation of the Cavitron technique by conifer pit aspiration.

PubMed

Beikircher, B; Ameglio, T; Cochard, H; Mayr, S

2010-07-01

The Cavitron technique facilitates time and material saving for vulnerability analysis. The use of rotors with small diameters leads to high water pressure gradients (DeltaP) across samples, which may cause pit aspiration in conifers. In this study, the effect of pit aspiration on Cavitron measurements was analysed and a modified 'conifer method' was tested which avoids critical (i.e. pit aspiration inducing) DeltaP. Four conifer species were used (Juniperus communis, Picea abies, Pinus sylvestris, and Larix decidua) for vulnerability analysis based on the standard Cavitron technique and the conifer method. In addition, DeltaP thresholds for pit aspiration were determined and water extraction curves were constructed. Vulnerability curves obtained with the standard method showed generally a less negative P for the induction of embolism than curves of the conifer method. Differences were species-specific with the smallest effects in Juniperus. Larix showed the most pronounced shifts in P(50) (pressure at 50% loss of conductivity) between the standard (-1.5 MPa) and the conifer (-3.5 MPa) methods. Pit aspiration occurred at the lowest DeltaP in Larix and at the highest in Juniperus. Accordingly, at a spinning velocity inducing P(50), DeltaP caused only a 4% loss of conductivity induced by pit aspiration in Juniperus, but about 60% in Larix. Water extraction curves were similar to vulnerability curves indicating that spinning itself did not affect pits. Conifer pit aspiration can have major influences on Cavitron measurements and lead to an overestimation of vulnerability thresholds when a small rotor is used. Thus, the conifer method presented here enables correct vulnerability analysis by avoiding artificial conductivity losses.

Elimination of trench defects and V-pits from InGaN/GaN structures

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

Smalc-Koziorowska, Julita; Grzanka, Ewa; Czernecki, Robert

2015-03-09

The microstructural evolution of InGaN/GaN multiple quantum wells grown by metalorganic chemical vapor phase epitaxy was studied as a function of the growth temperature of the GaN quantum barriers (QBs). We observed the formation of basal stacking faults (BSFs) in GaN QBs grown at low temperature. The presence of BSFs terminated by stacking mismatch boundaries (SMBs) leads to the opening of the structure at the surface into a V-shaped trench loop. This trench may form above an SMB, thereby terminating the BSF, or above a junction between the SMB and a subsequent BSF. Fewer BSFs and thus fewer trench defectsmore » were observed in GaN QBs grown at temperatures higher than 830 °C. Further increase in the growth temperature of the GaN QBs led to the suppression of the threading dislocation opening into V-pits.« less

Special Analysis: Disposal Plan for Pit 38 at Technical Area 54, Area G

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

French, Sean B.; Shuman, Rob

2012-06-26

Los Alamos National Laboratory (LANL) generates radioactive waste as a result of various activities. Operational waste is generated from a wide variety of research and development activities including nuclear weapons development, energy production, and medical research; environmental restoration (ER), and decontamination and decommissioning (D&D) waste is generated as contaminated sites and facilities at LANL undergo cleanup or remediation. The majority of this waste is low-level radioactive waste (LLW) and is disposed of at the Technical Area 54 (TA-54), Area G disposal facility. U.S. Department of Energy (DOE) Order 435.1 (DOE, 2001) requires that radioactive waste be managed in a mannermore » that protects public health and safety, and the environment. To comply with this order, DOE field sites must prepare site-specific radiological performance assessments for LLW disposal facilities that accept waste after September 26, 1988. Furthermore, sites are required to conduct composite analyses that account for the cumulative impacts of all waste that has been (or will be) disposed of at the facilities and other sources of radioactive material that may interact with the facilities. Revision 4 of the Area G performance assessment and composite analysis was issued in 2008 (LANL, 2008). These analyses estimate rates of radionuclide release from the waste disposed of at the facility, simulate the movement of radionuclides through the environment, and project potential radiation doses to humans for several on- and off-site exposure scenarios. The assessments are based on existing site and disposal facility data, and on assumptions about future rates and methods of waste disposal. The Area G disposal facility consists of Material Disposal Area (MDA) G and the Zone 4 expansion area. To date, disposal operations have been confined to MDA G and are scheduled to continue in that region until MDA G undergoes final closure at the end of 2013. Given its impending closure, efforts have been made to utilize the remaining disposal capacity within MDA G to the greatest extent possible. One approach for doing this has been to dispose of low-activity waste from cleanup operations at LANL in the headspace of selected disposal pits. Waste acceptance criteria (WAC) for the material placed in the headspace of pits 15, 37, and 38 have been developed (LANL, 2010) and the impacts of placing waste in the headspace of these units has been evaluated (LANL, 2012a). The efforts to maximize disposal efficiency have taken on renewed importance because of the disposal demands placed on MDA G by the large volumes of waste that are being generated at LANL by cleanup efforts. For example, large quantities of waste were recently generated by the retrieval of waste formerly disposed of at TA-21, MDA B. A portion of this material has been disposed of in the headspace of pit 38 in compliance with the WAC developed for that disposal strategy; a large amount of waste has also been sent to off-site facilities for disposal. Nevertheless, large quantities of MDA B waste remain that require disposal. An extension of pit 38 was proposed to provide the disposal capacity that will be needed to dispose of institutional waste and MDA B waste through 2013. A special analysis was prepared to evaluate the impacts of the pit extension (LANL, 2012b). The analysis concluded that the disposal unit could be extended with modest increases in the exposures projected for the Area G performance assessment and composite analysis, as long as limits were placed on the radionuclide concentrations in the waste that is placed in the headspace of the pit. Based, in part, on the results of the special analysis, the extension of pit 38 was approved and excavation of the additional disposal capacity was started in May 2012. The special analysis presented here uses performance modeling to identify a disposal plan for the placement of waste in pit 38. The modeling uses a refined design of the disposal unit and updated radionuclide inventories to identify a disposal configuration that promotes efficient utilization of the pit and ensures continued compliance with DOE Order 435.1 performance objectives. Section 2 describes the methods used to conduct the analysis; the results of the evaluation are provided in Section 3. The disposal plan for pit 38 is provided in Section 4 and the conclusions of the investigation are provided in Section 5. Throughout the report, pit 38 is used to refer to the entire disposal unit, including the existing pit and the extension that is currently under construction. Where a distinction between the two portions of the pit is necessary, the existing unit is referred to as pit 38 proper and the new portion of the pit as the pit 38 extension or, more simply, the extension.« less

An Open Pit Nanofluidic Tool: Localized Chemistry Assisted by Mesoporous Thin Film Infiltration.

PubMed

Mercuri, Magalí; Pierpauli, Karina A; Berli, Claudio L A; Bellino, Martín G

2017-05-17

Nanofluidics based on nanoscopic porous structures has emerged as the next evolutionary milestone in the construction of versatile nanodevices with unprecedented applications. However, the straightforward development of nanofluidically interconnected systems is crucial for the production of practical devices. Here, we demonstrate that spontaneous infiltration into supramolecularly templated mesoporous oxide films at the edge of a sessile drop in open air can be used to connect pairs of landmarks. The liquids from the drops can then join through the nanoporous network to guide a localized chemical reaction at the nanofluid-front interface. This method, here named "open-pit" nanofluidics, allows mixing reagents from nanofluidically connected droplet reservoirs that can be used as reactors to conduct reactions and precipitation processes. From the fundamental point of view, the work contributes to unveiling subtle phenomena during spontaneous infiltration of fluids in bodies with nanoscale dimensions such as the front broadening effect and the oscillatory behavior of the infiltration-evaporation front. The approach has distinctive advantages such as easy fabrication, low cost, and facility of scaling up for future development of ultrasensitive detection, controlled nanomaterial synthesis, and novel patterning methods.

Psychoanalytic-Interactional Therapy versus Psychodynamic Therapy by Experts for Personality Disorders: A Randomized Controlled Efficacy-Effectiveness Study in Cluster B Personality Disorders.

PubMed

Leichsenring, Falk; Masuhr, Oliver; Jaeger, Ulrich; Rabung, Sven; Dally, Andreas; Dümpelmann, Michael; Fricke-Neef, Christian; Steinert, Christiane; Streeck, Ulrich

2016-01-01

With regard to cluster B personality disorders, most psychotherapeutic treatments focus on borderline personality disorder. Evidence-based treatments for patients with other cluster B personality disorders are not yet available. Psychoanalytic-interactional therapy (PIT) represents a transdiagnostic treatment for severe personality disorders. PIT has been applied in clinical practice for many years and has proven effective in open studies. In a randomized controlled trial, we compared manual-guided PIT to nonmanualized pychodynamic therapy by experts in personality disorders (E-PDT) in patients with cluster B personality disorders. In an inpatient setting, patients with cluster B personality disorders were randomly assigned to manual-guided PIT (n = 64) or nonmanualized E-PDT (n = 58). In addition, a quasi-experimental control condition was used (n = 46) including both patients receiving treatment as usual and patients waiting for treatment. Primary outcomes were level of personality organization and overall psychological distress. As secondary outcomes, depression, anxiety and interpersonal problems were examined. No significant improvements were found in the control patients. Both PIT and E-PDT achieved significant improvements in all outcome measures and were superior to the control condition. No differences were found between PIT and E-PDT in any outcome measure at the end of treatment. The type of cluster B personality disorder had no impact on the results. In an inpatient setting, both PIT and E-PDT proved to be superior to a control condition in cluster B personality disorders. In a head-to-head comparison, both treatments appeared to be equally effective. Further research on the treatment of cluster B personality disorders is required. © 2016 S. Karger AG, Basel.

Governing in the Sunshine: Open Meetings, Open Records, and Effective Governance in Public Higher Education. Public Policy Paper Series No. 04-01

ERIC Educational Resources Information Center

Hearn, James C.; McLendon, Michael K.; Gilchrist, Leigh Z.

2004-01-01

Sunshine laws are designed to make meetings and records of public entities visible so that a state can help ensure accountability of decision making affecting public resources. The laws often pit the news media's desire for greater public disclosure of information on public college and university governance against institutional leaders' desire to…

Tunable phonon-induced transparency in bilayer graphene nanoribbons.

PubMed

Yan, Hugen; Low, Tony; Guinea, Francisco; Xia, Fengnian; Avouris, Phaedon

2014-08-13

In the phenomenon of plasmon-induced transparency, which is a classical analogue of electromagnetically induced transparency (EIT) in atomic gases, the coherent interference between two plasmon modes results in an optical transparency window in a broad absorption spectrum. With the requirement of contrasting lifetimes, typically one of the plasmon modes involved is a dark mode that has limited coupling to the electromagnetic radiation and possesses relatively longer lifetime. Plasmon-induced transparency not only leads to light transmission at otherwise opaque frequency regions but also results in the slowing of light group velocity and enhanced optical nonlinearity. In this article, we report an analogous behavior, denoted as phonon-induced transparency (PIT), in AB-stacked bilayer graphene nanoribbons. Here, light absorption due to the plasmon excitation is suppressed in a narrow window due to the coupling with the infrared active Γ-point optical phonon, whose function here is similar to that of the dark plasmon mode in the plasmon-induced transparency. We further show that PIT in bilayer graphene is actively tunable by electrostatic gating and estimate a maximum slow light factor of around 500 at the phonon frequency of 1580 cm(-1), based on the measured spectra. Our demonstration opens an avenue for the exploration of few-photon nonlinear optics and slow light in this novel two-dimensional material.

Sediment Transport and Slope Stability of Ship Shoal Borrow Areas for Coastal Restoration of Louisiana

NASA Astrophysics Data System (ADS)

Liu, H.; Xu, K.; Bentley, S. J.; Li, C.; Miner, M. D.; Wilson, C.; Xue, Z.

2017-12-01

Sandy barrier islands along Louisiana coast are degrading rapidly due to both natural and anthropogenic factors. Ship Shoal is one of the largest offshore sand resources, and has been used as a borrow area for Caminada Headland Restoration Project. Our knowledge of sediment transport and infilling processes in this new sandy and dynamic borrow area is rather limited. High resolution sub-bottom seismic data, side scan sonar images, multi-beam bathymetry and laser sediment grain size data were used to study seafloor morphological evolution and pit wall stability in response to both physical and geological processes. The multi-beam bathymetry and seismic profiling inside the pit showed that disequilibrium conditions led to rapid infilling in the pits at the beginning, but this process slowed down after the pit slope became stable and topography became smooth. We hypothesize that the erosion of the adjacent seabed sediment by energetic waves and longshore currents, the supply of suspended sediment from the rivers, and the erodible materials produced by local mass wasting on pit walls are three main types of infilling sediments. Compared with mud-capped dredge pits, this sandy dredge pit seems to have more gentle slopes on pit walls, which might be controlled by the angle of repose. Infilling sediment seems to be dominantly sandy, with some mud patches on bathymetric depressions. This study helps us better understand the impacts of mining sediment for coastal restoration and improves sand resource management efforts.

Morphological Response of a Mud Capped Dredge Pit in Western Louisiana After Sand Excavation for Barrier Island Restoration

NASA Astrophysics Data System (ADS)

Robichaux, P. A.; Xu, K.; Bentley, S. J.; Li, C.; Miner, M. D.

2017-12-01

Sand resources play a crucial role in supporting tourism, maintaining coastal ecosystems, and protecting property and infrastructure. Mud capped dredge pits (MCDPs) are created when paleochannel sand, covered by muddy shelf overburden, is excavated for restoration purposes; such paleochannels are one significant sand resource for coastal barrier protection. However, our knowledge of MCDPs is limited. To improve understanding of their morphological behavior, a dredge pit called Peveto Channel (PC) offshore of Holly Beach, LA, was studied in 2016. Our study consisted of a survey using multiple geophysical methods, including multibeam bathymetry, sidescan sonar, subbottom profiling, and magnetometry. Results indicate that PC has undergone 100% infilling since dredging occurred. Although the pit is filled up, analyses indicate the newly deposited material is unconsolidated and has yet to equilibrate to the ambient seafloor conditions. The surface of the pit area is pockmarked and uneven, likely caused by degassing processes and differential consolidation. Sidescan sonar images confirm that the pit walls have experienced little to no lateral erosion and are well preserved. The results from this survey and from historical surveys conducted in 2003 (a few months after dredging), 2004, 2006, and 2007 are compared to previously constructed numerical models used to predict the behavior of dredge pits. To our knowledge, PC is the only filled-up offshore dredge pit in coastal Louisiana. Thus the findings of this study provide new long-term information for regulatory policies and the feasibility of MCDPs as sand resources in the future.

Atomic force microscopy of the intervessel pit membrane in the stem of Sapium sebiferum (Euphorbiacea)

Treesearch

Thomas C. Pesacreta; Leslie H. Groom; Timothy G. Rials

2005-01-01

Sapwood and juvenile wood of Sapium sebiferum (Euphorbiacea) was collected during 2000-2002. In air-dried vessel elements, the surface of pit membranes (PMs) in the outermost growth ring was coated with plaque-like or interstitial material that was 2-5 nm thick. This coating was phase dark and overlaid a phase bright layer of globules and...

Ground-water conditions and effects of mine dewatering in Desert Valley, Humboldt and Pershing Counties, northwestern Nevada, 1962-91

USGS Publications Warehouse

Berger, D.L.

1995-01-01

Desert Valley is a 1,200-square-mile, north- trending, structural basin, about 30 miles northwest of Winnemucca, Nevada. Unconsolidated basin-fill deposits exceeding 7,000 feet in thickness constitute the primary ground-water reservoir. Dewatering operations at an open-pit mine began in the Spring of 1985 in the northeast part of Desert Valley. Ground-water withdrawal for mine dewatering in 1991 was greater than three times the estimated average annual recharge from precipitation. The mine discharge water has been allowed to flow to areas west of the mine where it has created an artificial wetlands. This report documents the 1991 hydrologic conditions in Desert Valley and the change in conditions since predevelopment (pre-1962). It also summarizes the results of analyzing the simulated effects of open-pit mine dewatering on a basin-wide scale over time. Water-level declines associated with the dewatering have propagated north and south of the mine, but have been attenuated to the west due to the infiltration beneath the artificial wetlands. Maximum water-level declines beneath the open pits at the mine, as of Spring 1991, are about 300 feet. Changes in the hydrologic conditions since predevelopment are observed predominantly near the dewatering operations and the associated discharge lakes. General ground-water chemistry is essentially unchanged since pre- development. On the basis of a ground-water flow model used to simulate mine dewatering, a new equilibrium may slowly be approached only after 100 years of recovery from the time mine dewatering ceases.

Investigating Mars: Rabe Crater

NASA Image and Video Library

2017-12-14

This VIS image of Rabe Crater is dominated by the extensive dunes that cover the crater floor. To the top of the image part of the pit is visible, as well as a small peninsula that has been eroded into the upper level floor materials. On the upper elevation on the side left of the peninsula the dunes cascade onto the lower pit elevation. There is also a slight arc to the dunes on the pit floor due to how the peninsula changed the wind pattern. Rabe Crater is 108 km (67 miles) across. Craters of similar size often have flat floors. Rabe Crater has some areas of flat floor, but also has a large complex pit occupying a substantial part of the floor. The interior fill of the crater is thought to be layered sediments created by wind and or water action. The pit is eroded into this material. The eroded materials appear to have stayed within the crater forming a large sand sheet with surface dune forms as well as individual dunes where the crater floor is visible. The dunes also appear to be moving from the upper floor level into the pit. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 52206 Latitude: -43.6573 Longitude: 34.9551 Instrument: VIS Captured: 2013-09-20 13:07 https://photojournal.jpl.nasa.gov/catalog/PIA22142

High-density polyethylene pipe: A new material for pass-by passive integrated transponder antennas

USGS Publications Warehouse

Kazyak, David C.; Zydlewski, Joseph D.

2012-01-01

Pass-by passive integrated transponder (PIT) antennas are widely used to study the movements of fish in streams. At many sites, stream conditions make it difficult to maintain antennas and obtain a continuous record of movement. We constructed pass-by PIT antennas by using high-density polyethylene (HDPE) and found them to be robust to high flows and winter ice flows. Costs for HDPE antennas were similar to those of traditional polyvinyl chloride (PVC) antennas, although construction was somewhat more complicated. At sites where PVC antennas are frequently damaged, HDPE is a durable and economical alternative for PIT antenna construction.

Trees for strip-mined lands

Treesearch

George Hart; William R. Byrnes

1960-01-01

Open-pit or strip mining has become an important method of mining bituminous coal in Pennsylvania. In 1958 some 19.5 million tons of soft coal - 29 percent of the total bituminous production in the State - were produced by this method.

46 CFR 108.173 - Class I, Division 2 locations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... locations. The following are Class I, Division 2 locations: (a) An enclosed space that has any open portion... mud pit. (b) A location in the weather that is— (1) Within the boundaries of the drilling derrick up...

75 FR 52780 - Notice of Availability of Final Supplemental Environmental Impact Statement for the Moore Ranch...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-27

... considered, but were eliminated from detailed analysis include: conventional mining (whether by open pit or... Agencywide Documents and Management System (ADAMS), which provides text and image files of the NRC's public...

Mars Methane Analogue Mission (M3): Analytical Techniques and Operations

NASA Astrophysics Data System (ADS)

Cloutis, E.; Vrionis, H.; Qadi, A.; Bell, J. F.; Berard, G.; Boivin, A.; Ellery, A.; Jamroz, W.; Kruzelecky, R.; Mann, P.; Samson, C.; Stromberg, J.; Strong, K.; Tremblay, A.; Whyte, L.; Wing, B.

2011-03-01

The Mars Methane Analogue Mission (M3) project is designed to simulate a rover-based search for, and analysis of, methane sources on Mars at a serpentinite open pit mine in Quebec, using a variety of instruments.

In situ nanoscale observations of gypsum dissolution by digital holographic microscopy.

PubMed

Feng, Pan; Brand, Alexander S; Chen, Lei; Bullard, Jeffrey W

2017-06-01

Recent topography measurements of gypsum dissolution have not reported the absolute dissolution rates, but instead focus on the rates of formation and growth of etch pits. In this study, the in situ absolute retreat rates of gypsum (010) cleavage surfaces at etch pits, at cleavage steps, and at apparently defect-free portions of the surface are measured in flowing water by reflection digital holographic microscopy. Observations made on randomly sampled fields of view on seven different cleavage surfaces reveal a range of local dissolution rates, the local rate being determined by the topographical features at which material is removed. Four characteristic types of topographical activity are observed: 1) smooth regions, free of etch pits or other noticeable defects, where dissolution rates are relatively low; 2) shallow, wide etch pits bounded by faceted walls which grow gradually at rates somewhat greater than in smooth regions; 3) narrow, deep etch pits which form and grow throughout the observation period at rates that exceed those at the shallow etch pits; and 4) relatively few, submicrometer cleavage steps which move in a wave-like manner and yield local dissolution fluxes that are about five times greater than at etch pits. Molar dissolution rates at all topographical features except submicrometer steps can be aggregated into a continuous, mildly bimodal distribution with a mean of 3.0 µmolm -2 s -1 and a standard deviation of 0.7 µmolm -2 s -1 .

Designing local solutions for emptying pit latrines in low-income urban settlements (Malawi)

NASA Astrophysics Data System (ADS)

Chipeta, W. C.; Holm, R. H.; Kamanula, J. F.; Mtonga, W. E.; de los Reyes, F. L.

2017-08-01

A lack of effective options in local technology poses challenges when onsite household sanitation facilities are eventually filled to capacity in unplanned settlement areas within Mzuzu City, located in northern Malawi. Vacuum trucks currently dominate the market but focus on emptying septic tanks in the more easily accessible planned settlement areas, rather than servicing the pit latrines common in unplanned settlement areas. As a result, households in the unplanned settlement areas within Mzuzu rely primarily on manual pit emptying (i.e., shoveling by hand) or digging a new pit latrine. These practices have associated health risks and are limited by space constraints. This research focused on filling the technological gap through the design, development, and testing of a pedal powered modified Gulper pump using locally available materials and fabrication. A modified pedal powered Gulper technology was developed and demonstrated to be capable of lifting fecal sludge from a depth of 1.5 m with a mean flow rate of 0.00058 m3/s. If the trash content was low, a typical pit latrine with a volume of 1-4 m3 could be emptied within 1-2 h. Based on the findings in our research Phase IV, the pedal powered Gulper modification is promising as a potential emptying technology for lined pit latrines in unplanned settlement areas. The success rate of the technology is about 17% (5 out 30 sampled lined pit latrines were successful) and reflects the difficulty in finding a single technology that can work well in all types of pit latrines with varying contents. We note that cost should not be the only design criteria and acknowledge the challenge of handling trash in pit latrines.

Monitoring of surface deformation in open pit mine using DInSAR time-series: a case study in the N5W iron mine (Carajás, Brazil) using TerraSAR-X data

NASA Astrophysics Data System (ADS)

Mura, José C.; Paradella, Waldir R.; Gama, Fabio F.; Santos, Athos R.; Galo, Mauricio; Camargo, Paulo O.; Silva, Arnaldo Q.; Silva, Guilherme G.

2014-10-01

We present an investigation of surface deformation using Differential SAR Interferometry (DInSAR) time-series carried out in an active open pit iron mine, the N5W, located in the Carajás Mineral Province (Brazilian Amazon region), using 33 TerraSAR-X (TSX-1) scenes. This mine has presented a historical of instability and surface monitoring measurements over sectors of the mine (pit walls) have been done based on ground based radar. Two complementary approaches were used: the standard DInSAR configuration, as an early warning of the slope instability conditions, and the DInSAR timeseries analysis. In order to decrease the topographic phase error a high resolution DEM was generated based on a stereo GeoEye-1 pair. Despite the fact that a DinSAR contains atmospheric and topographic phase artifacts and noise, it was possible to detect deformation in some interferometric pairs, covering pit benches, road ramps and waste piles. The timeseries analysis was performed using the 31 interferometric pairs, which were selected based on the highest mean coherence of a stack of 107 interferograms, presenting less phase unwrapping errors. The time-series deformation was retrieved by the Least-Squares (LS) solution using an extension of the Singular Value Decomposition (SVD), with a set of additional weighted constrain on the acceleration deformation. The atmospheric phase artifacts were filtered in the space-time domain and the DEM height errors were estimated based on the normal baseline diversity. The DInSAR time-series investigation showed good results for monitoring surface displacement in the N5W mine located in a tropical rainforest environment, providing very useful information about the ground movement for alarm, planning and risk assessment.

Partial trisomy 11q involving chromosome 1 detected by fluorescence in situ hybridization

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

McCorquodale, M.; Bereziouk, O.; McCorquodale, D.J.

1994-09-01

Partial trisomy 11q was detected in an infant delivered 3-4 weeks prematurely. The phenotype included slanted palpebral fissures, high arched palate, developmental delay, microcephaly, and cardiac defects, all of which occur in the majority of cases with this syndrome. Other features included a column-shaped skull, preauricular pit, single palmar crease, short, broad great toes, flat occiput, unilateral kidney agenesis, and strabismus. Chromosomes obtained from peripheral blood cells revealed the presence of extra material on the long arm of chromosome 1. The G-banding pattern of this extra material indicated that it might be derived from chromosome 1 or 11. Chromosomal {open_quotes}paints{close_quotes}more » showed that it was not chromosome 1 material, but was chromosome 11 material extending from band q21 to qter. Partial trisomy 11q arising from translocation of the 11q material to chromosome 2, 3, 4, 5, 6, 9, 10, 13, 17, 21, 22, and X has been reported previously, whereas translocation to chromosome 1 has not. The chromosome to which the 11q material is translocated does not alter the most frequent features of the partial trisomy 11q syndrome, but may influence other less common features.« less

Construction integrity assessment report (ETN-98-0005) S-Farm overground transfer (OGT) system valve pit 241-S-B to valve pit 241-S-D

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

HICKS, D.F.

1999-08-12

The S-Farm overground transfer (OGT) line will bypass the existing line(s), between valve pits 241-S-B and 241-S-D that no longer meet system requirements. The new OGT line will provide a waste transfer pipeline between these valve pits in support of saltwell pumping activities. The length of the OGT line is approximately 180 ft from pit to pit. The primary pipe is nominal 1-in. diameter stainless steel (SST) braided Ethylene-propylene Diene Monomer (EPDM) hose. The encasement pipe is a nominal 3-in., flanged, SST pipe made up of several different length pipe spool pieces (drawing H-2-829564, sh. 1 and sh. 2). Themore » OGT line slopes from valve pit 241-S-B toward valve pit 241-S-D. At each end, the primary and encasement pipe connect to a pit entry spool piece. The pit entry spool pieces are constructed of prefabricated SST materials. These spool pieces allow for the separation of the primary and encasement pipelines after the pipes have entered the valve pits (drawing H-2-818280, sh. 2). The pit entry spool pieces also allow for leak detection of the encasement pipe at each end (drawing H-2-829564, sh. 2). The OGT encasement pipeline is supported above ground by adjustable height unistrut brackets and precast concrete bases (drawing H-2-829654, sh. 1). The pipeline is heat-traced and insulated. The heat tracing and insulation supply and retain latent heat that prevents waste solidification during transfers and provides freeze protection. The total length of the pipeline is above ground, thereby negating the need for cathodic corrosion protection. This Construction Integrity Assessment Report (CIAR) is prepared by Fluor Daniel Northwest for Numatec Hanford Corporation/Lockheed Martin Hanford Corporation, the operations contractor, and the U. S. Department of Energy, the system owner. The CIAR is intended to verify that construction was performed in accordance with the provisions of Washington Administrative Code, WAC-173-303-640 (3) (c), (e), (f) and (h).« less

Fukushima Nuclear Accident Recorded in Tibetan Plateau Snow Pits

PubMed Central

Wang, Ninglian; Wu, Xiaobo; Kehrwald, Natalie; Li, Zhen; Li, Quanlian; Jiang, Xi; Pu, Jianchen

2015-01-01

The β radioactivity of snow-pit samples collected in the spring of 2011 on four Tibetan Plateau glaciers demonstrate a remarkable peak in each snow pit profile, with peaks about ten to tens of times higher than background levels. The timing of these peaks suggests that the high radioactivity resulted from the Fukushima nuclear accident that occurred on March 11, 2011 in eastern Japan. Fallout monitoring studies demonstrate that this radioactive material was transported by the westerlies across the middle latitudes of the Northern Hemisphere. The depth of the peak β radioactivity in each snow pit compared with observational precipitation records, suggests that the radioactive fallout reached the Tibetan Plateau and was deposited on glacier surfaces in late March 2011, or approximately 20 days after the nuclear accident. The radioactive fallout existed in the atmosphere over the Tibetan Plateau for about one month. PMID:25658094

Mineral resource of the month: barite

USGS Publications Warehouse

Miller, M. Michael

2006-01-01

Also called barytes, barite forms in various geologic environments and is frequently found with both metallic and nonmetallic minerals. Most barite is produced by open-pit mining techniques, and most crude barite requires some upgrading to meet minimum purity or specific gravity levels.

Effect of post weld impact treatment (PWIT) on mechanical properties of spot-welded joint

NASA Astrophysics Data System (ADS)

Ghazali, F. A.; Salleh, Z.; Hyie, K. M.; Rozlin, N. M. Nik; Hamidi, S. H. Ahmad; Padzi, M. M.

2017-12-01

This paper focuses on the study of improvement for spot welding on the tensile shear and hardness by applying post weld impact treatment (PWIT) on the welded joint. The main objective of the research is to characterize and improve the mechanical properties of the joint. The method of PWIT used on the welded joint was Pneumatic Impact Treatment (PIT). The concept of PIT on spot welding is that it improves the mechanical properties of the welded zone. The working sample was undergoing a resistance spot welding of joining two similar in dimension and material of a steel plate before treated. The dimension of both plate are 110 mm × 45 mm × 1.2 mm and the material used were low carbon steel (LCS). All the welded samples were tested for its mechanical properties by performing the tensile-shear and hardness test. Tensile-shear test was conducted on the spot welded, both treated and as-welded samples using crosshead speed of 2 mm/min, while hardness test was performed using 1kgf load via Vickers hardness indenter. The effects of PIT on tensile-shear properties and hardness were evaluated and found that the implementation of PIT has increased tensile shear and hardness significantly.

Fabrication of (Ba,K)Fe2As2 tapes by ex situ PIT process using Ag-Sn alloy single sheath

NASA Astrophysics Data System (ADS)

Togano, K.; Gao, Z.; Matsumoto, A.; Kikuchi, A.; Kumakura, H.

2017-01-01

Instead of ordinal pure Ag, Ag-based Sn binary alloys (up to 7.5 at%Sn) with higher mechanical strength are used for the sheath material of ex situ powder-in-tube (PIT)-processed (Ba,K)Fe2As2(Ba-122) tapes. We found that the use of the Ag-Sn alloy enhances the densification and texturing of the Ba-122 core, resulting in higher transport, J c. Moreover, the optimum heat treatment temperature for a high J c can be lowered by around 100 °C due to the higher packing density of the Ba-122 core prior to the final heat treatment. We also found that the smoothness of the interface between the sheath and Ba-122 core is significantly improved by using the Ag-Sn binary alloy sheaths. These results show that the Ag-Sn alloy is promising as a sheath material in PIT-processed Ba-122 superconducting wires.

The application of PIT tags to measure transport of detrital coral fragments on a fringing reef: Majuro Atoll, Marshall Islands

NASA Astrophysics Data System (ADS)

Ford, Murray R.

2014-06-01

Passive integrated transponder (PIT) tags are a radio-frequency identification device widely used as a machine-readable identification tool in fisheries research. PIT tags have also been employed, to a lesser extent, to track the movement of gravel-sized clasts within fluvial and coastal systems. In this study, PIT tags were inserted into detrital coral fragments and used to establish source-sink transport pathways on a fringing reef on Majuro Atoll in the Marshall Islands. Results suggest the transport of gravel-sized material on the inter-tidal reef flat is exclusively across-reef towards the lagoon. Considerable variation in the distance travelled by fragments was observed. Fragments were largely intact and visually recognisable after almost 5 months on the reef flat. However, the branches of some recovered fragments had broken off and corallite abrasion was observed in recovered fragments. This study indicates that PIT tags are an inexpensive and powerful new addition to the suite of sediment transport and taphonomic tools for researchers working within coral reef systems.

RCRA Facility Investigation/Remedial Investigation Report with Baseline Risk Assessment for the Central Shops Burning/Rubble Pit (631-6G), Volume 1 Final

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

NONE

1996-04-01

The Burning/Rubble Pits at the Savannah River Site were usually shallow excavations approximately 3 to 4 meters in depth. Operations at the pits consisted of collecting waste on a continuous basis and burning on a monthly basis. The Central Shops Burning/Rubble Pit 631- 6G (BRP6G) was constructed in 1951 as an unlined earthen pit in surficial sediments for disposal of paper, lumber, cans and empty galvanized steel drums. The unit may have received other materials such as plastics, rubber, rags, cardboard, oil, degreasers, or drummed solvents. The BRP6G was operated from 1951 until 1955. After disposal activities ceased, the areamore » was covered with soil. Hazardous substances, if present, may have migrated into the surrounding soil and/or groundwater. Because of this possibility, the United States Environmental Protection Agency (EPA) has designated the BRP6G as a Solid Waste Management Unit (SWMU) subject to the Resource Conservation Recovery Act/Comprehensive Environmental Response, Compensation and Liability Act (RCRA/CERCLA) process.« less

Sublimation as a landform-shaping process on Pluto

NASA Astrophysics Data System (ADS)

Moore, Jeffrey M.; Howard, Alan D.; Umurhan, Orkan M.; White, Oliver L.; Schenk, Paul M.; Beyer, Ross A.; McKinnon, William B.; Spencer, John R.; Grundy, Will M.; Lauer, Tod R.; Nimmo, Francis; Young, Leslie A.; Stern, S. Alan; Weaver, Harold A.; Olkin, Cathy B.; Ennico, Kimberly; New Horizons Science Team

2017-05-01

Fields of pits, both large and small, in Tombaugh Regio (Sputnik Planitia, and the Pitted Uplands to the east), and along the scarp of Piri Rupes, are examples of landscapes on Pluto where we conclude that sublimation drives their formation and evolution. Our heuristic modeling closely mimics the form, spacing, and arrangement of a variety of Tombaugh Regio's pits. Pluto's sublimation modified landforms appear to require a significant role for (diffusive) mass wasting as suggested by our modeling. In our models, the temporal evolution of pitted surfaces is such that initially lots of time passes with little happening, then eventually, very rapid development of relief and rapid sublimation. Small pits on Sputnik Planitia are consistent with their formation in N2-dominated materials. As N2-ice readily flows, some other ``stiffer'' volatile ice may play a role in supporting the relief of sublimation degraded landforms that exhibit several hundred meters of relief. A strong candidate is CH4, which is spectroscopically observed to be associated with these features, but the current state of rheological knowledge for CH4 ice at Pluto conditions is insufficient for a firm assessment.

Burner rig hot corrosion of silicon carbide and silicon nitride

NASA Technical Reports Server (NTRS)

Fox, Dennis S.; Smialek, James L.

1990-01-01

A number of commercially available SiC and Si3N4 materials were exposed to 1000 C for 40 h in a high-velocity, pressurized burner rig as a simulation of an aircraft turbine environment. Na impurities (2 ppm) added to the burner flame resulted in molten Na2SO4 deposition, attack of the SiC and Si3N4, and formation of substantial Na2O+x(SiO2) corrosion product. Room-temperature strength of the materials decreased as a result of the formation of corrosion pits in SiC and grain-boundary dissolution and pitting in Si3N4.

Column leaching and sorption experiments to assess the mobility of potentially toxic elements in industrially contaminated land.

PubMed

Anderson, P; Davidson, C M; Duncan, A L; Littlejohn, D; Ure, A M; Garden, L M

2000-06-01

Made-up ground collected from layers of a trial pit excavated on a former industrial site was treated with artificial rainwater in a series of column leaching and sorption experiments. Metal mobility and the ability of various layers of material obtained from the pit to act as sources or sinks of potentially toxic elements were assessed. Samples from different layers varied in their abilities to raise the pH of rainwater applied at pH 3.5 and 4.3, and this was reflected in the amounts of metals mobilised by the rainwater as it percolated through the soil column. Material from the top two layers of the pit released cadmium, copper, manganese, lead, nickel and zinc to the aqueous phase, but the lower layers, with higher buffering capacity, were able to resist acidification even when the equivalent of 12 months' rainfall (western UK) was applied. Column sorption experiments confirmed the ability of material from layer 4 (48-50 cm) to take up copper, manganese and zinc. Metals were determined in the leachates by flame and electrothermal atomic absorption spectrometry and principle anions by ion chromatography.

Proposed Iraq/Afghanistan War-Lung Injury (IAW-LI) Clinical Practice Recommendations: National Academy of Sciences' Institute of Medicine Burn Pits Workshop.

PubMed

Szema, Anthony; Mirsaidi, Niely; Patel, Bhumika; Viens, Laura; Forsyth, Edward; Li, Jonathan; Dang, Sophia; Dukes, Brittany; Giraldo, Jheison; Kim, Preston; Burns, Matthew

2017-11-01

High rates of respiratory symptoms (14%) and new-onset asthma in previously healthy soldiers (6.6%) have been reported among military personnel post-deployment to Iraq and Afghanistan. The term Iraq/Afghanistan War-Lung Injury (IAW-LI) is used to describe the constellation of respiratory diseases related to hazards of war, such as exposure to burning trash in burn pits, improvised explosive devices, and sandstorms. Burnpits360.org is a nonprofit civilian website which voluntarily tracks medical symptoms among soldiers post-deployment to the Middle East. Subsequent to initiation of the Burnpits360.org website, the Department of Veterans Affairs started the Airborne Hazards and Open Burn Pit registry. This paper: (a) analyzes the latest 38 patients in the Burnpits360.org registry, validated by DD214 Forms; (b) compares strengths and weaknesses of both registries as outlined at the National Academy of Sciences Institute of Medicine Burn Pits Workshop; (c) further characterizes the spectrum of disease in IAW-LI; (d) describes the risk factors of affected populations; (e) summarizes current practices regarding management of the condition; and (f) defines future research objectives.

Proposed Iraq/Afghanistan War-Lung Injury (IAW-LI) Clinical Practice Recommendations: National Academy of Sciences’ Institute of Medicine Burn Pits Workshop

PubMed Central

Szema, Anthony; Mirsaidi, Niely; Patel, Bhumika; Viens, Laura; Forsyth, Edward; Li, Jonathan; Dang, Sophia; Dukes, Brittany; Giraldo, Jheison; Kim, Preston; Burns, Matthew

2015-01-01

High rates of respiratory symptoms (14%) and new-onset asthma in previously healthy soldiers (6.6%) have been reported among military personnel post-deployment to Iraq and Afghanistan. The term Iraq/Afghanistan War-Lung Injury (IAW-LI) is used to describe the constellation of respiratory diseases related to hazards of war, such as exposure to burning trash in burn pits, improvised explosive devices, and sandstorms. Burnpits360.org is a nonprofit civilian website which voluntarily tracks medical symptoms among soldiers post-deployment to the Middle East. Subsequent to initiation of the Burnpits360.org website, the Department of Veterans Affairs started the Airborne Hazards and Open Burn Pit registry. This paper: (a) analyzes the latest 38 patients in the Burnpits360.org registry, validated by DD214 Forms; (b) compares strengths and weaknesses of both registries as outlined at the National Academy of Sciences Institute of Medicine Burn Pits Workshop; (c) further characterizes the spectrum of disease in IAW-LI; (d) describes the risk factors of affected populations; (e) summarizes current practices regarding management of the condition; and (f) defines future research objectives. PMID:26669772

Real-time monitoring of hemodynamic changes in tumor vessels during photoimmunotherapy using optical coherence tomography

NASA Astrophysics Data System (ADS)

Liang, Chia-Pin; Nakajima, Takahito; Watanabe, Rira; Sato, Kazuhide; Choyke, Peter L.; Chen, Yu; Kobayashi, Hisataka

2014-09-01

Photoimmunotherapy (PIT) is a cell-specific cancer therapy based on an armed antibody conjugate that induces rapid and highly selective cancer cell necrosis after exposure to near-infrared (NIR) light. The PIT treatment also induces the superenhanced permeability and retention effect, which allows high concentrations of nanoparticles to accumulate in the tumor bed. In our pilot studies, optical coherence tomography (OCT) reveals dramatic hemodynamic changes during PIT. We developed and applied speckle variance analysis, Doppler flow measurement, bulk motion removal, and automatic region of interest selection to quantify vessel diameter and blood velocity within tumors in vivo. OCT imaging reveals that blood velocity in peripheral tumor vessels quickly drops below the detection limit while the vessel lumen remains open (4 vessels from 3 animals). On the other hand, control tumor vessels (receive NIR illumination but no PIT drug) do not show the sustained blood velocity drop (5 vessels from 3 animals). Ultraslow blood velocity could result in a long drug circulation time in tumor. Increase of the blood pool volume within the central tumor (shown in histology) may be the leading cause of the periphery blood velocity drop and could also increase the drug pool volume in tumor vessels.

Coal and Open-pit surface mining impacts on American Lands (COAL)

NASA Astrophysics Data System (ADS)

Brown, T. A.; McGibbney, L. J.

2017-12-01

Mining is known to cause environmental degradation, but software tools to identify its impacts are lacking. However, remote sensing, spectral reflectance, and geographic data are readily available, and high-performance cloud computing resources exist for scientific research. Coal and Open-pit surface mining impacts on American Lands (COAL) provides a suite of algorithms and documentation to leverage these data and resources to identify evidence of mining and correlate it with environmental impacts over time.COAL was originally developed as a 2016 - 2017 senior capstone collaboration between scientists at the NASA Jet Propulsion Laboratory (JPL) and computer science students at Oregon State University (OSU). The COAL team implemented a free and open-source software library called "pycoal" in the Python programming language which facilitated a case study of the effects of coal mining on water resources. Evidence of acid mine drainage associated with an open-pit coal mine in New Mexico was derived by correlating imaging spectrometer data from the JPL Airborne Visible/InfraRed Imaging Spectrometer - Next Generation (AVIRIS-NG), spectral reflectance data published by the USGS Spectroscopy Laboratory in the USGS Digital Spectral Library 06, and GIS hydrography data published by the USGS National Geospatial Program in The National Map. This case study indicated that the spectral and geospatial algorithms developed by COAL can be used successfully to analyze the environmental impacts of mining activities.Continued development of COAL has been promoted by a Startup allocation award of high-performance computing resources from the Extreme Science and Engineering Discovery Environment (XSEDE). These resources allow the team to undertake further benchmarking, evaluation, and experimentation using multiple XSEDE resources. The opportunity to use computational infrastructure of this caliber will further enable the development of a science gateway to continue foundational COAL research.This work documents the original design and development of COAL and provides insight into continuing research efforts which have potential applications beyond the project to environmental data science and other fields.

76 FR 63954 - Notice of Lodging of Consent Decree Under the Comprehensive Environmental Response, Compensation...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-14

... associated with waste rock piles and open mine pits present at the Site. Additionally, the Consent Decree... United States of America v. Newmont USA Limited, DJ. Ref. 90-11-3-1749. Commenters may request an...

Uranium Mining and Norm in North America-Some Perspectives on Occupational Radiation Exposure.

PubMed

Brown, Steven H; Chambers, Douglas B

2017-07-01

All soils and rocks contain naturally occurring radioactive materials (NORM). Many ores and raw materials contain relatively elevated levels of natural radionuclides, and processing such materials can further increase the concentrations of naturally occurring radionuclides. In the U.S., these materials are sometimes referred to as technologically-enhanced naturally occurring radioactive materials (TENORM). Examples of NORM minerals include uranium ores, monazite (a source of rare earth minerals), and phosphate rock used to produce phosphate fertilizer. The processing of these materials has the potential to result in above-background radiation exposure to workers. Following a brief review of the sources and potential for worker exposure from NORM in these varied industries, this paper will then present an overview of uranium mining and recovery in North America, including discussion on the mining methods currently being used for both conventional (underground, open pit) and in situ leach (ISL), also referred to as In Situ Recovery (ISR), and the production of NORM materials and wastes associated with these uranium recovery methods. The radiological composition of the NORM products and wastes produced and recent data on radiological exposures received by workers in the North American uranium recovery industry are then described. The paper also identifies the responsible government agencies in the U.S. and Canada assigned the authority to regulate and control occupational exposure from these NORM materials.

Human imprint on archaeological anthroposols: first assessment of combined micromophological, pedological and lipid biomarkers analyses of organic matter

NASA Astrophysics Data System (ADS)

Cammas, Cécilia; Thuy Nguyen Tu, Thanh; Plessis, Marion; Clotuche, Raphaël; Derenne, Sylvie

2013-04-01

Archaeological anthroposol matrix contains significant amounts of fine organic matter (OM), which can give archaeological information. Geoarchaeological studies of OM aim to reveal its origin in order to reconstruct past human activities. Such studies are complex because the nature and the abundance of OM is the result of human activities together with natural processes. Also, MO evolves over time, a process that is not well understood. Combination of complementary approaches may give further insights into human imprint on archaeological anthroposols. For example, micromorphology gives data on in situ activities and pedological processes with the result that components of animal and vegetal origin can be identified but not some amorphous / fibrous material and very fine residues (< ~10 µm). On the other hand, pedological and geochemical analyses of bulk samples are often disconnected from contextual studies. Our work aims to (i) identify morphological and geochemical markers of human activity at different scales, (ii) compare results of different analytical methods to better understand the relation between matrix components and features, chemical properties, and geochemical markers, and (iii) infer relations between pedo-sedimentary history and OM preservation. Two tanning pits in urban craft areas were selected for sampling, as they are likely to contain large amounts of organic matter of vegetal and animal origin. The pit of Saint-Denis (SDN, 10 km at the north of Paris, calcareous alluvium, 13th cAD) was a reference tanning pit. The pit of Famars (FAM, near the Belgian border, luvisols, Roman period) was hypothesized to be a part of the tanning process. To assess preservation of organic components and molecules in relation with pedo-sedimentary context and their potential as biomarkers of human activities, methodology combined micromorphology, pedological analysis (C, N, LOI, P total, organic and inorganic phosphorus) and lipid analysis by GC/MS, lipids having a high preservation potential and containing biomarkers indicative of OM origin. Micromorphological study showed a high amount and diversity of organic components in the two pits. At the SDN pit, the interpretation of tanning (liming) was supported by the presence of scarce fragments of lime with calcitic hairs pseudomorphoses. Plant remains and bone fragments were identified, but red fibrous and yellow amorphous material were not. At the FAM pit, bones and coprolithic material were scarce, but there were abundant vegetal remains such as decaying and burnt fragments, as well as siliceous skeletons. Initial results of organic chemistry show that lipids were preserved (0,13 % for SDN, 0,09 % for FAM), and that lipids of vegetal origin were dominant in the two samples. At SDN, both plant and faecal material biomarkers were identified in the form of various sterols and coprostanol, respectively. Lipids extracted from FAM included ubiquitous compounds as well as plant biomarkers, but no faecal markers. The structure of several compounds is still to be elucidated. However, initial results may suggest that vegetal imprint in thin section and in lipid analysis can be correlated. For animal remains, the two methods seem to lead to different but complementary conclusions; the difference noted for inferred source material will be investigated in term of cultural and contextual origin.

The electrical properties and glass transition of some dental materials after temperature exposure.

PubMed

Marcinkowska, Agnieszka; Gauza-Wlodarczyk, Marlena; Kubisz, Leszek; Hedzelek, Wieslaw

2017-10-17

The physicochemical properties of dental materials will remain stable only when these materials in question are resistant to the changes in the oral cavity. The oral environment is subject to large temperature variations. The aim of the study was the assessment of electrical properties and glass transition of some dental materials after temperature exposure. Composite materials, compomers, materials for temporary prosthetic replacement and resin-based pit and fissure sealants were used in the study. The method used was electric conductivity of materials under changing temperature. The order of materials presenting the best characteristics for insulators was as follows: materials for temporary prosthetic replacement, resin-based pit and fissure sealants, composites, and compomers. Thanks to comparisons made between graphs during I and II heating run, the method could be used to observe changes in the heated material and determine whether the changes observed are reversible or permanent. The graphs also provided temperature values which contain information on glass transition during heating. In the oral cavity the effect of the constant temperature stimulus influences maturity of dental materials and improves their properties. But high temperatures over glass transition temperature can cause irreversible deformation and changes of the materials properties, even in a short time.

Furniture Rack Corrosion Coupon Surveillance - 2012 Update

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

Mickalonis, J. I.; Murphy, T. R.; Berry, C. J.

Under the L Basin corrosion surveillance program furniture rack coupons immersed for 14 years (FY2009 coupons) and 16 years (FY2011 coupons) were analyzed and the results trended with coupons exposed for shorter times. In addition, a section harvested from an actual furniture rack that was immersed for 14 years was analyzed for pitting in the weld and heat-affected-zone (HAZ) regions. The L Basin operations maintained very good water quality over the entire immersion period for these samples. These results for FY2009 and FY2011 coupons showed that the average pit depths for the 6061 and 6063 base metal are 1 andmore » 2 mils, respectively, while those for the weld and HAZ are 3 and 4 mils, respectively. The results for the weld and HAZ regions are similar to coupons removed during the period of FY2003 to FY2007. These similarities indicate that the pit development occurred quickly followed by slow kinetics of increase in pit depth. For the actual furniture rack sample average pits of 5 and 2 mils were measured for the HAZ and weld, respectively. These results demonstrate that pitting corrosion of the aluminum furniture racks used to support the spent fuel occurs in waters of good quality. The corrosion kinetics or pit depth growth rate is much less that 1 mil/year, and would not impact long-term use of this material system for fuel storage racks in L Basin if good water quality is maintained.« less

Wear of two pit and fissure sealants in contact with primary teeth

PubMed Central

Galo, Rodrigo; Contente, Marta Maria Martins Giamatei; Borsatto, Maria Cristina

2014-01-01

Objectives: Wear simulations may provide an indication of the clinical performance of pit-and-fissure sealants when associated with primary teeth as counterbody, restricting the involved variables. The aim of this study was to evaluate wear of dental materials used as pit-and-fissure sealants in contact with primary teeth. Materials and Methods: A resinous sealant (Fluroshield®) and a resin-modified glass ionomer cement (Vitremer®) were selected in a post-plate design, using as counterbody primary tooth pins (4 × 4 × 2 mm) at 3 and 10 N vertical load, 1 Hz frequency, 900 wear cycles in artificial saliva (n = 15). Attrition coefficient values were obtained and the material and primary tooth volumes were analyzed. Data were analyzed statistically by ANOVA and Duncan's test (P < 0.05). Results: Fluroshield® presented the highest attrition coefficient values for the 3 N but these values decreased significantly for the 10 N load. The means for volume loss (3 mm) of the different samples after the wear test were not statistically different for the materials. The volume loss values for the primary teeth were statistically different and there was an increase in volume loss with the increase of the load applied in the wear tests. Conclusions: Differences were also observed with regard to the surface deformation characteristics. The wear rates of primary tooth enamel vary according to the type of material and the load applied during mastication. PMID:24966777

Limited mobility of dioxins near San Jacinto super fund site (waste pit) in the Houston Ship Channel, Texas due to strong sediment sorption.

PubMed

Louchouarn, Patrick; Seward, Shaya M; Cornelissen, Gerard; Arp, Hans Peter H; Yeager, Kevin M; Brinkmeyer, Robin; Santschi, Peter H

2018-07-01

Sediments from a waste pit in Houston Ship Channel (HSC) were characterized using a number of molecular markers of natural organic matter fractions (e.g., pyrogenic carbon residues, PAHs, lignins), in addition to dioxins, in order to test the hypothesis that the dispersal and mobility of dioxins from the waste pit in the San Jacinto River is minimal. Station SG-6, sampled at the site of the submerged waste pit, had the highest dioxin/furan concentrations reported for the Houston Ship Channel/Galveston Bay (HSC/GB) system (10,000-46,000 pg/g), which translated into some of the highest reported World Health Organization Toxic Equivalents (TEQs: 2000-11,000 pg/g) in HSC sediments. Using a multi-tracer approach, this study confirmed our hypothesis that sludges from chlorinated pulps are a very likely source of dioxins/furans to this pit. However, this material also contained large quantities of additional hydrophobic organic contaminants (PAHs) and pyrogenic markers (soot-BC, levoglucosan), pointing to the co-occurrence of petroleum hydrocarbons and combustion byproducts. Comparison of dioxin/furan signatures in the waste pit with those from sediments of the HSC and a control site suggests that the remobilization of contaminated particles did not occur beyond the close vicinity of the pit itself. The dioxins/furans in sediments outside the waste pit within the HSC are rather from other diffuse inputs, entering the sedimentary environment through the air and water, and which are comprised of a mixture of industrial and municipal sources. Fingerprinting of waste pit dioxins indicates that their composition is typical of pulp and paper sources. Measured pore water concentrations were 1 order of magnitude lower than estimated values, calculated from a multiphase sorption model, indicating low mobility of dioxins within the waste pit. This is likely accomplished by co-occurring and strong sorbing pyrogenic and petrogenic residues in the waste pit, which tend to keep dioxins strongly sorbed to particles. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Growth and dislocation studies of β-HMX.

PubMed

Gallagher, Hugh G; Sherwood, John N; Vrcelj, Ranko M

2014-01-01

The defect structure of organic materials is important as it plays a major role in their crystal growth properties. It also can play a subcritical role in "hot-spot" detonation processes of energetics and one such energetic is cyclotetramethylene-tetranitramine, in the commonly used beta form (β-HMX). The as-grown crystals grown by evaporation from acetone show prismatic, tabular and columnar habits, all with {011}, {110}, (010) and (101) faces. Etching on (010) surfaces revealed three different types of etch pits, two of which could be identified with either pure screw or pure edge dislocations, the third is shown to be an artifact of the twinning process that this material undergoes. Examination of the {011} and {110} surfaces show only one type of etch pit on each surface; however their natural asymmetry precludes the easy identification of their Burgers vector or dislocation type. Etching of cleaved {011} surfaces demonstrates that the etch pits can be associated with line dislocations. All dislocations appear randomly on the crystal surfaces and do not form alignments characteristic of mechanical deformation by dislocation slip. Crystals of β-HMX grown from acetone show good morphological agreement with that predicted by modelling, with three distinct crystal habits observed depending upon the supersaturation of the growth solution. Prismatic habit was favoured at low supersaturation, while tabular and columnar crystals were predominant at higher super saturations. The twin plane in β-HMX was identified as a (101) reflection plane. The low plasticity of β-HMX is shown by the lack of etch pit alignments corresponding to mechanically induced dislocation arrays. On untwinned {010} faces, two types of dislocations exist, pure edge dislocations with b = [010] and pure screw dislocations with b = [010]. On twinned (010) faces, a third dislocation type exists and it is proposed that these pits are associated with pure screw dislocations with b = [010]. Graphical abstractEtch pits on the twinned (010) face of β-HMX.

Accelerated slab replacement using temporary precast panels and self-consolidating concrete : [summary].

DOT National Transportation Integrated Search

2016-06-01

Researchers at Florida State University demonstrated the feasibility of using precast reinforced concrete panels to temporarily fill slab removal pits. The precast slabs can be driven on so traffic lanes can be open during the day, and new slab casti...

Tanacetum vulgare as a bioindicator of trace-metal contamination: a study of a naturally colonized open-pit lignite mine.

PubMed

Jasion, Mateusz; Samecka-Cymerman, Aleksandra; Kolon, Krzysztof; Kempers, Alexander J

2013-10-01

We investigated the possibility of use of Tanacetum vulgare (tansy) as an ecological indicator of metal concentration in a naturally colonized open-pit lignite mine in Bełchatów (Poland). Tanacetum vulgare is the only species growing abundantly and spontaneously in the lignite mine waste dumps. Metal concentrations in roots, stems, leaves, flowers, and soil were measured in dump sites differing in type and time of reclamation and therefore differing in pollution levels. Tanacetum vulgare appeared to be an accumulator of chromium and iron in roots, whereas highest concentrations of manganese and zinc were found in leaves. A high bioaccumulation factor for cadmium (Cd) was observed in dumps and control sites, indicating that even small amounts of Cd in the environment may result in significant uptake by the plant. The lowest concentrations of metals were found in plants from sites situated on dumps reclaimed with argillaceous limestone.

Air quality status of an open pit mining area in India.

PubMed

Chaulya, S K

2005-06-01

This investigation presents the assessment of ambient air quality carried out at an open pit coal mining area in Orissa state of India. The 24-h average concentrations of suspended particulate matter (SPM), respirable particulate matter (RPM, particles of less than 10 microm aerodynamic diameter), sulphur dioxide (SO2) and oxides of nitrogen (NO(x)) were determined at regular interval throughout one year at 13 monitoring stations in residential area and four stations in mining/industrial area. During the study period, the 24-h and annual average SPM and RPM concentrations exceeded the respective standards set in the Indian ambient air quality standard (NAAQS) protocol in most of the residential and industrial areas. However, the 24-h and annual average concentrations of SO2 and NO(x) were well within the prescribed limit of the NAAQS in both residential and industrial areas. A management strategy is formulated for effective control of particulate matter at source and other mitigative measures are recommended including implementation of green belts around the sensitive areas.

Electrical Current Leakage and Open-Core Threading Dislocations in AlGaN-Based Deep Ultraviolet Light-Emitting Diodes.

DOE PAGES

Moseley, Michael William; Allerman, Andrew A.; Crawford, Mary H.; ...

2014-08-04

Electrical current transport through leakage paths in AlGaN-based deep ultraviolet (DUV) lightemitting diodes (LEDs) and their effect on LED performance are investigated. Open-core threading dislocations, or nanopipes, are found to conduct current through nominally insulating Al0.7Ga0.3N layers and limit the performance of DUV-LEDs. A defect-sensitive phosphoric acid etch reveals these opencore threading dislocations in the form of large, micron-scale hexagonal etch pits visible with optical microscopy, while closed-core screw-, edge-, and mixed-type threading dislocations are represented by smaller and more numerous nanometer-scale pits visible by atomic-force microscopy. The electrical and optical performances of DUV-LEDs fabricated on similar Si-doped Al0.7Ga0.3N templatesmore » are found to have a strong correlation to the density of these nanopipes, despite their small fraction (<0.1% in this study) of the total density of threading dislocations.« less

Design and construction of a dual recharge system at Minot, North Dakota

USGS Publications Warehouse

Pettyjohn, Wayne A.

1968-01-01

In 1965, a ground-water recharge facility was constructed and placed in operation to forestall an impending water shortage at Minot, North Dakota. The facility is unique in that the rate of recharge to a buried sand and gravel aquifer is augmented by perforating an overlying bed of clay using hydraulic connectors (gravel-filled bored holes) in conjunction with an open-pit excavation. The connectors were drilled by typical well-boring techniques and the open pit was excavated by common construction methods. The recharge technique made it possible to add about million gallons per day of water to underground storage with a total capital investment of about $200,000. The alternative originally proposed was a 50-mile long pipeline to Garrison Reservoir, at a 1959 estimated cost of $12,000,000. The recharge technique employed at Minot should have wide application in the ground-water industry in areas where natural recharge to permeable deposits is impeded by overlying beds of low permeability.

Oil sands mining and reclamation cause massive loss of peatland and stored carbon

PubMed Central

Rooney, Rebecca C.; Bayley, Suzanne E.; Schindler, David W.

2012-01-01

We quantified the wholesale transformation of the boreal landscape by open-pit oil sands mining in Alberta, Canada to evaluate its effect on carbon storage and sequestration. Contrary to claims made in the media, peatland destroyed by open-pit mining will not be restored. Current plans dictate its replacement with upland forest and tailings storage lakes, amounting to the destruction of over 29,500 ha of peatland habitat. Landscape changes caused by currently approved mines will release between 11.4 and 47.3 million metric tons of stored carbon and will reduce carbon sequestration potential by 5,734–7,241 metric tons C/y. These losses have not previously been quantified, and should be included with the already high estimates of carbon emissions from oil sands mining and bitumen upgrading. A fair evaluation of the costs and benefits of oil sands mining requires a rigorous assessment of impacts on natural capital and ecosystem services. PMID:22411786

A simplified economic filter for open-pit gold-silver mining in the United States

USGS Publications Warehouse

Singer, Donald A.; Menzie, W. David; Long, Keith R.

1998-01-01

In resource assessments of undiscovered mineral deposits and in the early stages of exploration, including planning, a need for prefeasibility cost models exists. In exploration, these models to filter economic from uneconomic deposits help to focus on targets that can really benefit the exploration enterprise. In resource assessment, these models can be used to eliminate deposits that would probably be uneconomic even if discovered. The U. S. Bureau of Mines (USBM) previously developed simplified cost models for such problems (Camm, 1991). These cost models estimate operating and capital expenditures for a mineral deposit given its tonnage, grade, and depth. These cost models were also incorporated in USBM prefeasibility software (Smith, 1991). Because the cost data used to estimate operating and capital costs in these models are now over ten years old, we decided that it was necessary to test these equations with more current data. We limited this study to open-pit gold-silver mines located in the United States.

Orapa Diamond Mine, Botswana

NASA Image and Video Library

2015-11-16

This image from NASA Terra spacecraft shows the Orapa diamond mine, the world largest diamond mine by area. The mine is located in Botswana. It is the oldest of four mines operated by the same company, having begun operations in 1971. Orapa is an open pit style of mine, located on two kimberlite pipes. Currently, the Orapa mine annually produces approximately 11 million carats (2200 kg) of diamonds. The Letlhakane diamond mine is also an open pit construction. In 2003, the Letlhakane mine produced 1.06 million carats of diamonds. The Damtshaa diamond mine is the newest of four mines, located on top of four distinct kimberlite pipes of varying ore grade. The mine is forecast to produce about 5 million carats of diamond over the projected 31 year life of the mine. The image was acquired October 5, 2014, covers an area of 28 by 45 km, and is located at 21.3 degrees south, 25.4 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA20104

New Onset Migraine Associated With a Civilian Burn Pit.

PubMed

Chalela, Julio A

2017-05-01

Deployed service members exposed to burn pit smoke can experience a multitude of symptoms. Respiratory symptoms after burn pit smoke exposure are well recognized, but neurologic symptoms are less well recognized. There are reports of migraines triggered by odors but no specific reports of new onset migraines triggered by exposure to burn pit smoke. Clinicians encountering patients with new onset migraines in the deployed setting face the dilemma of evacuating the patients to perform neuroimaging or keeping them in theatre. Retrospective case series study and review of the literature. Three patients with new onset headache after exposure to open burn pit smoke are described. The headaches met established criteria to be classified as migraine with aura in two patients and migraine without aura in one patient. The migraines were triggered by exposure to the burn pit smoke and relieved by avoidance of the smoke. The patients did not have history of migraine and had normal neurological examinations. Computed tomography performed in one patient and optic nerve insonation performed in all three patients were normal. The patients responded well to triptans and antiemetic medicines. Nociceptive odors can trigger classic migraines in adults without prior history of migraine. The temporal association between exposure to the odor and the development of the headache, the absence of abnormalities on neurologic examination, and the response to triptans help establish the diagnosis. Activation of the trigeminal system leading to release of pain-related neuropeptides may mediate the migrainous symptoms. Evacuation for advanced neuroimaging or specialized consultation can be avoided if the above-mentioned criteria are met. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

Magnetic Barkhausen noise indications of stress concentrations near pits of various depths

NASA Astrophysics Data System (ADS)

Mandal, K.; Loukas, M. E.; Corey, A.; Atherton, D. L.

1997-11-01

The presence of a defect in a material under stress, changes the local stress distribution around it. This local stress distributions around three circular pits in line pipe steel with depths of 30, 50 and 80% wall thickness were studied nondestructively by magnetic Barkhausen noise measurements and in the presence of different bending stresses. The results show stress concentration factors ˜ 1.5, 1.7 and 2.05, respectively, and are consistent with theoretical predictions.

Soft valves in plants

NASA Astrophysics Data System (ADS)

Park, Keunhwan; Tixier, Aude; Christensen, Anneline; Arnbjerg-Nielsen, Sif; Zwieniecki, Maciej; Jensen, Kaare

2017-11-01

Water and minerals flow from plant roots to leaves in the xylem, an interconnected network of vascular conduits that spans the full length of the organism. When a plant is subjected to drought stress, air pockets can spread inside the xylem, threatening the survival of the plant. Many plants prevent propagation of air by using hydrophobic nano-membranes in the ``pit'' pores that link adjacent xylem cells. This adds considerable resistance to flow. Interestingly, torus-margo pit pores in conifers are open and offer less resistance. To prevent propagation of air, conifers use a soft gating mechanism, which relies on hydrodynamic interactions between the xylem liquid and the elastic pit. However, it is unknown exactly how it is able to combine the seemingly antagonist functions of high permeability and resistance to propagation of air. We conduct experiments on biomimetic pores to elucidate the flow regulation mechanism. The design of plant valves is compared to other natural systems and optimal strategies are discussed. This work was supported by a research Grant (13166) from VILLUM FONDEN.

HIP1 exhibits an early recruitment and a late stage function in the maturation of coated pits.

PubMed

Gottfried, Irit; Ehrlich, Marcelo; Ashery, Uri

2009-09-01

Huntingtin interacting protein 1 (HIP1) is an accessory protein of the clathrin-mediated endocytosis (CME) pathway, yet its precise role and the step at which it becomes involved are unclear. We employed live-cell imaging techniques to focus on the early steps of CME and characterize HIP1 dynamics. We show that HIP1 is highly colocalized with clathrin at the plasma membrane and shares similar dynamics with a subpopulation of clathrin assemblies. Employing transferrin receptor fused to pHluorin, we distinguished between open pits to which HIP1 localizes and newly internalized vesicles that are devoid of HIP1. Moreover, shRNA knockdown of clathrin compromised HIP1 membranal localization, unlike the reported behavior of Sla2p. HIP1 fragment, lacking its ANTH and Talin-like domains, inhibits internalization of transferrin, but retains colocalization with membranal clathrin assemblies. These data demonstrate HIP1's role in pits maturation and formation of the coated vesicle, and its strong dependence on clathrin for membranal localization.

Surface mining

Treesearch

Robert Leopold; Bruce Rowland; Reed Stalder

1979-01-01

The surface mining process consists of four phases: (1) exploration; (2) development; (3) production; and (4) reclamation. A variety of surface mining methods has been developed, including strip mining, auger, area strip, open pit, dredging, and hydraulic. Sound planning and design techniques are essential to implement alternatives to meet the myriad of laws,...

Understanding of surface pit formation mechanism of GaN grown in MOCVD based on local thermodynamic equilibrium assumption

NASA Astrophysics Data System (ADS)

Zhi-Yuan, Gao; Xiao-Wei, Xue; Jiang-Jiang, Li; Xun, Wang; Yan-Hui, Xing; Bi-Feng, Cui; De-Shu, Zou

2016-06-01

Frank’s theory describes that a screw dislocation will produce a pit on the surface, and has been evidenced in many material systems including GaN. However, the size of the pit calculated from the theory deviates significantly from experimental result. Through a careful observation of the variations of surface pits and local surface morphology with growing temperature and V/III ratio for c-plane GaN, we believe that Frank’s model is valid only in a small local surface area where thermodynamic equilibrium state can be assumed to stay the same. If the kinetic process is too vigorous or too slow to reach a balance, the local equilibrium range will be too small for the center and edge of the screw dislocation spiral to be kept in the same equilibrium state. When the curvature at the center of the dislocation core reaches the critical value 1/r 0, at the edge of the spiral, the accelerating rate of the curvature may not fall to zero, so the pit cannot reach a stationary shape and will keep enlarging under the control of minimization of surface energy to result in a large-sized surface pit. Project supported by the National Natural Science Foundation of China (Grant Nos. 11204009 and 61204011) and the Beijing Municipal Natural Science Foundation, China (Grant No. 4142005).

Microscopic observations of X-ray and gamma-ray induced decomposition of ammonium perchlorate crystals

NASA Technical Reports Server (NTRS)

Herley, P. J.; Levy, P. W.

1972-01-01

The X-ray and gamma-ray induced decomposition of ammonium perchlorate was studied by optical, transmission, and scanning electron microscopy. This material is a commonly used oxidizer in solid propellents which could be employed in deep-space probes, and where they will be subjected to a variety of radiations for as long as ten years. In some respects the radiation-induced damage closely resembles the effects produced by thermal decomposition, but in other respects the results differ markedly. Similar radiation and thermal effects include the following: (1) irregular or ill-defined circular etch pits are formed in both cases; (2) approximately the same size pits are produced; (3) the pit density is similar; (4) the c face is considerably more reactive than the m face; and (5) most importantly, many of the etch pits are aligned in crystallographic directions which are the same for thermal or radiolytic decomposition. Thus, dislocations play an important role in the radiolytic decomposition process.

Variations in xylem embolism susceptibility under drought between intact saplings of three walnut species.

PubMed

Knipfer, Thorsten; Barrios-Masias, Felipe H; Cuneo, Italo F; Bouda, Martin; Albuquerque, Caetano P; Brodersen, Craig R; Kluepfel, Daniel A; McElrone, Andrew J

2018-05-30

A germplasm collection containing varied Juglans genotypes holds potential to improve drought resistance of plant materials for commercial production. We used X-ray computed microtomography to evaluate stem xylem embolism susceptibility/repair in relation to vessel anatomical features (size, arrangement, connectivity and pit characteristics) in 2-year-old saplings of three Juglans species. In vivo analysis revealed interspecific variations in embolism susceptibility among Juglans microcarpa, J. hindsii (both native to arid habitats) and J. ailantifolia (native to mesic habitats). Stem xylem of J. microcarpa was more resistant to drought-induced embolism as compared with J. hindsii and J. ailantifolia (differences in embolism susceptibility among older and current year xylem were not detected in any species). Variations in most vessel anatomical traits were negligible among the three species; however, we detected substantial interspecific differences in intervessel pit characteristics. As compared with J. hindsii and J. ailantifolia, low embolism susceptibility in J. microcarpa was associated with smaller pit size in larger diameter vessels, a smaller area of the shared vessel wall occupied by pits, lower pit frequency and no changes in pit characteristics as vessel diameters increased. Changes in amount of embolized vessels following 40 days of re-watering were minor in intact saplings of all three species highlighting that an embolism repair mechanism did not contribute to drought recovery. In conclusion, our data indicate that interspecific variations in drought-induced embolism susceptibility are associated with species-specific pit characteristics, and these traits may provide a future target for breeding efforts aimed at selecting walnut germplasm with improved drought resistance.

Quantifying Dynamic Changes on Surface of Comet 67P/Churyumov-Gerasimenko Using High-Resolution Photoclinometry DTMs

NASA Astrophysics Data System (ADS)

Tang, Y.; Birch, S.; Hayes, A.; Kirk, R. L.; Kutsop, N. W. S.; Squyres, S. W.

2017-12-01

Observations from ESA's Rosetta spacecraft of comet 67P/Churyumov-Gerasimenko (67P) have provided insights into the geological processes that act to modify the surface of a small, primitive body. The landscapes of 67P are shaped by both large scale violent changes, such as cliff collapses and jet events, as well as smaller and more subtle changes such as the formation of pits and ripples within the larger-scale granular deposits. Explosive jets are located through triangulating the same jet in multiple images. They appear to originate from locations close to numerous newly formed, small-scale pits, which were only observed after known jet events (for example, the jet observed on March 11th, 2015, in image N20150311T053737597ID30F22). This implies a possible link between these two dynamical processes. We generated high-resolution photoclinometric digital terrain models (DTM) of the surface of 67P (at 1.5m/pixel) in locations where recent jet events were observed and over surfaces where newly formed pits are observed. A comparison of DTMs generated of the surface both before and after the appearance of the pits provides insight to the magnitude of dynamical changes, including the volume of the ejected material. By tracking the change in the surface topography at such high resolution, we constrain both the volume of materials that are ejected from the surface during the jet event, and of materials that are retained in nearby deposits. By studying these events and their aftermath, it will be possible to formulate numerical models as to the formation of the jets and explain why and how they occur. We will use this information in conjunction with numerical modeling of the large-scale global transport of sedimentary materials on 67P, to facilitate a better understanding of cometary landscape evolution.

Investigating Mars: Rabe Crater

NASA Image and Video Library

2017-12-12

In this VIS image of the floor of Rabe Crater the step down into the pit is visible in the sinuous ridges on the left side of the image. The appearance of the exposed side of the cliffs does not look like a volcanic, difficult to erode material, but rather an easy to erode material such as layered sediments. Rabe Crater is 108 km (67 miles) across. Craters of similar size often have flat floors. Rabe Crater has some areas of flat floor, but also has a large complex pit occupying a substantial part of the floor. The interior fill of the crater is thought to be layered sediments created by wind and or water action. The pit is eroded into this material. The eroded materials appear to have stayed within the crater forming a large sand sheet with surface dune forms as well as individual dunes where the crater floor is visible. The dunes also appear to be moving from the upper floor level into the pit. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 34456 Latitude: -43.7164 Longitude: 34.4056 Instrument: VIS Captured: 2009-09-20 09:38 https://photojournal.jpl.nasa.gov/catalog/PIA22140

Tunable plasmon-induced transparency in plasmonic metamaterial composed of three identical rings

NASA Astrophysics Data System (ADS)

Tian, Yuchen; Ding, Pei; Fan, Chunzhen

2017-10-01

We numerically investigated the plasmon-induced transparency (PIT) effect in a three-dimensional plasmonic metamaterial composed of three identical rings. It is illustrated that the PIT effect appears as a result of the destructive interference between the electric dipole and the quadrupole resonance mode. By tuning gap distance, radius or rotation angle of the metamaterial, the required transmission spectra with a narrow sharp transparency peak can be realized. In particular, it is found that an on-to-off amplitude modulation of the PIT transparency window can be achieved by moving or rotating the horizontal ring. Two dips move to high frequency and low frequency regions, respectively, in the transmission spectra by moving the horizontal ring, namely, the width of transmission peak becomes larger. With the rotation of horizontal ring, both width and position of transmission peak are kept invariant. Our designed structure achieved a maximum group index of 352 in the visible frequency range, which has a significant slow light effect. Moreover, the PIT effect is explained based on the classical two-oscillator theory, which is in well agreement with the numerical results. It indicates our proposed structure and theoretical analysis may open up avenues for the tunable control of light in highly integrated optical circuits.

Influences of Cr/Ni equivalent ratios of filler wires on pitting corrosion and ductility-dip cracking of AISI 316L weld metals

NASA Astrophysics Data System (ADS)

Kim, Y. H.; Kim, D. G.; Sung, J. H.; Kim, I. S.; Ko, D. E.; Kang, N. H.; Hong, H. U.; Park, J. H.; Lee, H. W.

2011-02-01

To study the pitting corrosion of AISI 316L weld metals according to the chromium/nickel equivalent ratio (Creq/Nieq ratio), three filler wires were newly designed for the flux-cored arc welding process. The weld metal with delta-ferrite at less than 3 vol.%, was observed for ductility-dip cracking (DDC) in the reheated region after multi-pass welding. The tensile strength and yield strength increased with increasing Creq/Nieq ratio. The result of anodic polarization tests in a 0.1 M NaCl solution at the room temperature (25) for 45 min, revealed that the base metal and weld metals have a similar corrosion potential of -0.34 VSCE. The weld metal with the highest content of Cr had the highest pitting potential (0.39 VSCE) and the passivation range (0.64 VSCE) was higher than the base metal (0.21 VSCE and 0.46 VSCE, respectively). Adding 0.001 M Na2S to the 0.1M NaCl solution, the corrosion occurred more severely by H2S. The corrosion potentials of the base metal and three weld metals decreased to -1.0 VSCE. DDC caused the decrease of the pitting potential by inducing a locally intense corrosion attack around the crack openings.

Topography and Geomorphology of the Interior of Occator Crater on Ceres

NASA Astrophysics Data System (ADS)

Jaumann, Ralf

2017-04-01

With a diameter of 92km, Occator is one of the most prominent craters on Ceres. Its depth ranges from 4.8km along the crater rim to -1.1km at the crater floor with respect to a reference ellipsoid. Occator shows a set of specific features such as post impact formation crater filling including multiple flow features, a central pit with a dome in its center, extensional tectonics expressed as linear radial and concentric graben, and spectral variations indicating a complex formation process. We processed 550 LAMO stereo images from Cycle01-Cycle11 with a resolution of 35m/pixel to generate a high-resolution digital terrain model (DTM) of the Occator impact structure. Occator crater has mass wasting deposits originating from the crater rims and walls, which extend into the crater for 10 to 20km. However, in the southeast and northeast these mass wasting deposits are completely covered by crater floor plains material that extends from the crater center to the rim, ponding against the crater walls. The flows also superimpose the mass wasting deposits from the rims [1]. Furthermore, crater densities on Occator's interior deposits are slightly lower than on its ejecta blanket, indicating post-impact formation or target parameter variation between consolidated melt and unconsolidated ejecta deposits [2,3,4]. The terrain northwest of the central area is very rough, shows mass wasting deposits and is about 2km thick w.r.t the rim of the central pit. The plains to the southeast are smooth, pond against the crater wall, and are less than 500m thick w.r.t. the rim of the central pit The central pit is about 3.5km wide and 600m deep while the dome rises 250m within the pit [5]. In the northeast, multiple flows approaching the crater rim very closely. These flow plains are also less than 500m thick w.r.t. the rim of the central pit. Some of the flows seem to have been superposed on the lower parts of the crater wall and then flowed back into depressions of the plains. The flows to the northeast appear to originate from the central region and move slightly uphill. This indicates either a feeding zone that pushes the flows forward by supplying low-viscosity material or an extended subsidence of the crater center, possibly after discharging a subsurface reservoir [1,2], or lateral oscillations of an impact melt sheet during emplacement. The plains material covers an area of about 4750km2 with an average depth of about 250m resulting in a body of plains material of about 1200km3. The plains material is slightly younger than the impact event and the bright deposits are even younger than the plains material. Post impact processes might be due to impact melt, hydrothermal alteration, or cryovolcanic crater filling [1] K. Krohn et al, GRL43, 11994, (2016). [2] R. Jaumann et al., LPSC47, 1455 (2016). [3] N. Schmedemann et al, GRL43, 11987. (2016) [4] A. Neesemann, et al., Icarus, in prep. [5] P. Schenk, et al., LPSC47 (2016).

A Combined Multi-Material Euler/LaGrange Computational Analysis of Blast Loading Resulting from Detonation of Buried Landmines

DTIC Science & Technology

2008-01-01

phenomena. The work of Bergeron et al. [7] was subsequently extended by Braid [8] to incorporate different charge sizes, soil types and improved...place, a series of water hoses is placed in pit bottom to allow the introduction of water into the pit from the bottom. Next, approximately 14.2m3 of... Braid , 17th International MABS Symposium, Las Vegas, USA, June 2002. [8]. M. P. Braid , Defence R&D Canada, Suffield Special Publication, DRES SSSP

Cyclic Polarization Behavior of ASTM A537-Cl.1 Steel in the Vapor Space Above Simulated Waste

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

Wiersma, B

2004-11-01

An assessment of the potential degradation mechanisms of Types I and II High-Level Waste (HLW) Tanks determined that pitting corrosion and stress corrosion cracking were the two most significant degradation mechanisms. Specifically, nitrate induced stress corrosion cracking was determined to be the principal degradation mechanism for the primary tank steel of non-stress relieved tanks. Controls on the solution chemistry have been in place to preclude the initiation and propagation of degradation in the tanks. However, recent experience has shown that steel not in contact with the bulk waste solution or slurry, but exposed to the ''vapor space'' above the bulkmore » waste, may be vulnerable to the initiation and propagation of degradation, including pitting and stress corrosion cracking. A program to resolve the issues associated with potential vapor space corrosion is in place. The objective of the program is to develop understanding of vapor space (VSC) and liquid/air interface (LAIC) corrosion to ensure a defensible technical basis to provide accurate corrosion evaluations with regard to vapor space and liquid/air interface corrosion (similar to current evaluations). There are several needs for a technically defensible basis with sufficient understanding to perform these evaluations. These include understanding of the (1) surface chemistry evolution, (2) corrosion response through coupon testing, and (3) mechanistic understanding through electrochemical studies. Experimentation performed in FY02 determined the potential for vapor space and liquid/air interface corrosion of ASTM A285-70 and ASTM A537-Cl.1 steels. The material surface characteristics, i.e. mill-scale, polished, were found to play a key role in the pitting response. The experimentation indicated that the potential for limited vapor space and liquid/air interface pitting exists at 1.5M nitrate solution when using chemistry controls designed to prevent stress corrosion cracking. Experimentation performed in FY03 quantified pitting rates as a function of material surface characteristics, including mill-scale and defects within the mill-scale. Testing was performed on ASTM A537-Cl.1 (normalized) steel, the material of construction of the Type III HLW tanks. The pitting rates were approximately 3 mpy for exposure above inhibited solutions, as calculated from the limited exposure times. This translates to a penetration time of 166 years for a 0.5-in tank wall provided that the pitting rate remains constant and the bulk solution chemistry is maintained within the L3 limit. The FY04 testing consisted of electrochemical testing to potentially lend insight into the surface chemistry and further understand the corrosion mechanism in the vapor space. Electrochemical testing lends insight into the corrosion processes through the determination of current potential relationships. The results of the electrochemical testing performed during FY04 are presented here.« less

Why Save a Can?

ERIC Educational Resources Information Center

Gutierrez, Melida; Johnson, Cheryl

2009-01-01

This activity ties together the recycling of aluminum and the protection of rain forests. Students use critical thinking to study the effects of open pit mining of bauxite in rain forests and then draw their own conclusions about how to minimize the impact of bauxite mining and boost recycling efforts within their communities. Drawing conclusions…

The effect of inhibitor sodium nitrate on pitting corrosion of dissimilar material weldment joint of stainless steel AISI 304 and mild steel SS 400

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

Hilca, B. R., E-mail: bangkithilca@yahoo.com; Triyono, E-mail: triyonomesin@uns.ac.id

This study experimentally evaluated the effect of Sodium Nitrate inhibitor (NaNO{sub 3}) of 0.1%, 0.3%, and 0.5% on NaCl 3.5% toward pitting corrosion of dissimilar metal welding joint between stainless steel AISI 304 and mild steel SS 400. Electrochemical corrosion was tested using potentiodynamic polarization. Further the Scanning Electron Microscope (SEM) conducted to analyze the specimen. Chemical composition analysis used Energy Dispersive X-ray Spectrometry (EDS). The highest efficiency of sodium nitrate for ER 308 attained 63.8% and 64.89%for ER 309L. The specimen surface which observed through SEM showed decrease of pitting corrosion respectively with the addition of sodium nitrate contentmore » as inhibitor.« less

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

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

Ueda, T.; Nugraha, C.; Matsui, K.

2005-07-01

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

Map showing areas with potential for talc deposits in the Gravelly, Greenhorn, and Ruby ranges and the Henrys Lake Mountains of southwestern Montana

USGS Publications Warehouse

Van Gosen, Bradley S.; Berg, Richard B.; Hammarstrom, Jane M.

1998-01-01

For the last several years, Montana has been the leading talc producing state in the United States (U.S. Geological Survey, 1996). For example, in 1992 Montana supplied about 40 percent of the U.S. mine production of talc (Virta, 1992). All of this production has come from the large deposits of high purity talc in the southwestern part of the state. All Montana talc is currently (1997) extracted from four mines, each within the study area of this map—the open pit operations of the Treasure State, Regal, and Yellowstone mines and the underground operation of the Beaverhead mine (see map numbers 1-4 on list and map to the left). The related mineral chlorite is mined at the Antler mine, located nearby, but outside of the study area in the Highland Mountains. Montana talc has at least two market advantages: (1) some deposits are very large and near surface, allowing economic mining by open pit methods; and (2) the deposits are of high purity and lack tremolite or other amphibole mineral contaminants (such as absestos) that occur in some other talc-rich deposits. Talc from southwest Montana is used in ceramics, paint, paper, plastics, cosmetics, rubber, roofing, flooring, caulking, and agricultural applications. The talc is also used in the processes of recycling paper and plastics. Talc was first discovered in the early 1900's at the present site of the Yellowstone mine (Perry, 1948, p. 9). Modest production began in 1942 from shallow pits and adits, supplying steatite (massive, compact, high-purity) talc that was used to make ceramic insulators. The southwest Montana talc industry grew to become a significant part of the region's economy; this history is described by Perry (1948), Olson (1976), and Berg (1997). Exploration and development are likely to continue for the foreseeable future for several reasons: (1) mines are active in the area at present and an infrastructure for talc processing exists; (2) large changes in domestic and export talc markets are not expected in the next few years based on recent market trends (Virta, 1997); (3) the talc of this region is especially pure and asbestos-free; and (4) except for potential ground stabilization problems and land disturbance associated with largescale open pit mining, no significant environmental impacts are associated with talc mining

Evidence of stratabound liquefaction in the formation of fractured topographic margins, cone chains and pit catenas along the Martian Dichotomy Boundary and in Isidis Planitia, Mars.

NASA Astrophysics Data System (ADS)

Gallagher, C.; Balme, M. R.

2012-04-01

On the low-lying plains along much of the Martian Dichotomy Boundary (MDB) and in the Isidis impact basin, cones and curving chains of cones, referred to as thumbprint terrain (TPT), are common. In the same settings, pit chains (catenas) occur in orthogonal to curving and conchoidal fracture sets between mesa-like crustal blocks, generally at or near topographic margins. Many of the fractures consist of linked pits rather than simple propagated cracks. These assemblages are often associated with the more disaggregated populations of blocks comprising chaos terrain. We show that the local planimetric arrangement of the cone chains, fractures and pit catenas is strikingly similar in both shape and scale, including lateral separation, length, longitudinal slope and radius of curvature. The summits of cones tend to be closely accordant along individual cone chains. Neighbouring cone chains tend to be mutually accordant on low gradient basin surfaces but generally stepped en echelon closer to the fractured basin margins. Similarly, the crustal blocks (including very isolated block sets) are often mutually stepped, and fractures between these en echelon blocks tend to be very close to horizontal. Hence, many cone chains, fractures and pit catenas in fractures share the property of being arranged along strike. They diverge morphologically by the cone chains being positive forms separated by narrow gulfs but the pit catenas being negative forms separated by planar blocks. All of these characteristics point to the possibility that the arcuate cone chains and the arcuate pit catenas have a common origin. In particular, we hypothesise that the cone chains characteristic of TPT along the MDB and in Isidis are filled, indurated and then exhumed pit catenas revealed by the stripping-away of intervening blocks [cf. 1]. Many other surfaces on Mars are pervaded by pits and pit catenas, with evidence of former water flow through the catenas suggesting that ground-ice thaw played a role in at least one mode of catena formation [2]. As well as presenting the morphological evidence for a genetic association between TPT and pit catenas, we present corroborative evidence that fluvial channel networks on Mars have in places increased in complexity through the linking of pits arranged in linear to arcuate arrays, culminating in a pseudo-branching channel network. Such systems do not occur at topographic margins and did not disintegrate into stepped crustal blocks. However, the scale of these channels and the volumes of liquid intermittently impounded in craters along these channel systems indicate that pit chains are associated with significant excess groundwater production leading to channelized flow, including catastrophic discharges when crater-impounded lakes along-flow were breached. Are the MDB and Isidis cone chains exhumed pit catenas and are the pits the surface expression of more deep-seated conduits? Do pit catenas indicate excess pore-water production, sufficient to link individual pits and dissect crustal blocks? Together, do these assemblages reflect the degradation of the MDB and Isidis margins and the subsequent stripping of adjacent low-lying plains? The crucial observations presented in this research (cone chains lying between crustal blocks, together with the morphometric similarities) are consistent with the interpretation of the cones and catenas having a common origin. Consequently, we hypothesise that the translated, back-rotated, tilted and capsized disposition of en echelon blocks is very reminiscent of the morphology produced during lateral spreading [3] associated with stratabound liquefaction below a low-gradient, rigid, insensitive surface. Significantly, such liquefaction events cause extensive, arcuate ground fractures along with the discharge of sediment-laden groundwater from the liquefiable substratum to the surface through pipes and conical boils confined within inter-block fractures. These conduits and their injectite are frequently indurated by secondary mineralisation, often making them more competent and less erodible than the confining material. Most often, lateral spreads occur at coastlines, with basin-ward normal faulting and extension of the original surface. Generally, seismic shaking of susceptible materials is responsible for lateral spreading but pore-water pressure changes, e.g. due to rapid marine recession and drawdown, may also play a role. Given the basin-and-margin setting of the martian cone, pit and block assemblages described in this research, we speculate that all three broad morphological types reflect the degradation of extensive marine margins and the deflation of the interiors of marine basins during long-term marine recession. [1] Williams et al. (2007) in Willis et al. (eds), Utah Geological Association Publication 36. [2] Weitz et al. (2006) Icarus 184, 436-451. [3] Wang et al. (2005) Icarus 175, 551-555.

Gross and microscopic observations on the lingual structure of the Florida Manatee Trichechus manatus latirostris.

PubMed

Levin, M J; Pfeiffer, C J

2002-10-01

The tongue of the Florida manatee (Trichechus manatus latirostris) was studied macroscopically, light and electron microscopically. The tongue was slender, muscular and firmly fixed in the oral cavity; only the cranial tip was free and mobile. Numerous filiform papillae were distributed over the dorsal surface of the rostral tongue. Multiple raised, round fungiform-like papillae were distributed over most of the dorsum. Typical fungiform papillae were restricted to the lateral margins of the tongue. Foliate papillae, presenting as multi-fossulate openings, were noted on the caudolateral margins. Open pits were located on the dorsocaudal surface and lateral walls. Microscopic examination showed that most of the lingual dorsum was covered with a thick stratified squamous epithelium. Open pits led to well-developed mucous salivary glands. Glands within the foliate papillae were mostly mucous, although some seromucous glands were present. Taste buds were restricted to the epithelium of the foliate papillae. Throughout the tongue, striated muscle was abundant below the epithelium. Blood vessels, lymph channels and nerve fibres were freely distributed throughout the intermuscular stroma. Nerve fibres reacted positively with neurone specific enolase (NSE) antibody throughout the tongue, including nerve bundles, glands and taste buds. Clear to translucent vacuoles were found juxtaposed to nuclei in the stratum spinosum in the foliate papillae epithelium.

Structural graph-based morphometry: A multiscale searchlight framework based on sulcal pits.

PubMed

Takerkart, Sylvain; Auzias, Guillaume; Brun, Lucile; Coulon, Olivier

2017-01-01

Studying the topography of the cortex has proved valuable in order to characterize populations of subjects. In particular, the recent interest towards the deepest parts of the cortical sulci - the so-called sulcal pits - has opened new avenues in that regard. In this paper, we introduce the first fully automatic brain morphometry method based on the study of the spatial organization of sulcal pits - Structural Graph-Based Morphometry (SGBM). Our framework uses attributed graphs to model local patterns of sulcal pits, and further relies on three original contributions. First, a graph kernel is defined to provide a new similarity measure between pit-graphs, with few parameters that can be efficiently estimated from the data. Secondly, we present the first searchlight scheme dedicated to brain morphometry, yielding dense information maps covering the full cortical surface. Finally, a multi-scale inference strategy is designed to jointly analyze the searchlight information maps obtained at different spatial scales. We demonstrate the effectiveness of our framework by studying gender differences and cortical asymmetries: we show that SGBM can both localize informative regions and estimate their spatial scales, while providing results which are consistent with the literature. Thanks to the modular design of our kernel and the vast array of available kernel methods, SGBM can easily be extended to include a more detailed description of the sulcal patterns and solve different statistical problems. Therefore, we suggest that our SGBM framework should be useful for both reaching a better understanding of the normal brain and defining imaging biomarkers in clinical settings. Copyright © 2016 Elsevier B.V. All rights reserved.

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

Brandt, C.A.; Rickard, W.H. Jr.; Hefty, M.G.

This report describes the development of the reclamation project for the Hanford Site Near Surface Test Facility (NSTF), its implementation, and preliminary estimates of its success. The goal of the reclamation project is to return disturbed sites as nearly as practicable to their original conditions using native species. Gable Mountain is dominated by two plant communities: a big sagebrush (Artemisia tridentata) -- Sandberg's bluegrass (Poa sandbergii) community and a stiff sagebrush (Artemisia rigida) -- Sandberg's bluegrass community. Disassembly of the site installations began on March 15, 1988, and the site was returned to original contours by December 12, 1988. Twomore » separate revegetation methods were employed at the NSTF to meet differing site constraints. Vegetative cover and density in the revegetation plots were assessed in April 1989 and again in June 1989 and 1990. It is extremely unlikely that the sand pit, borrow pit, box cuts, generator pad area, or ventilation fan area will reach the reclamation objectives set for these areas within the next 50 years without further intervention. These areas currently support few living plants. Vegetation on revegetated native soils appears to be growing as expected. Vegetation growth on the main waterline is well below the objective. To date, no shrubs have grown on the area, growth of native grasses is well below the objective, and much of the area has been covered with the pit run material, which may not support adequate growth. Without further treatments, the areas without the pit run material will likely revert to a nearly pure cheatgrass condition. 44 refs., 13 figs., 7 tabs.« less

Deterministic ion beam material adding technology for high-precision optical surfaces.

PubMed

Liao, Wenlin; Dai, Yifan; Xie, Xuhui; Zhou, Lin

2013-02-20

Although ion beam figuring (IBF) provides a highly deterministic method for the precision figuring of optical components, several problems still need to be addressed, such as the limited correcting capability for mid-to-high spatial frequency surface errors and low machining efficiency for pit defects on surfaces. We propose a figuring method named deterministic ion beam material adding (IBA) technology to solve those problems in IBF. The current deterministic optical figuring mechanism, which is dedicated to removing local protuberances on optical surfaces, is enriched and developed by the IBA technology. Compared with IBF, this method can realize the uniform convergence of surface errors, where the particle transferring effect generated in the IBA process can effectively correct the mid-to-high spatial frequency errors. In addition, IBA can rapidly correct the pit defects on the surface and greatly improve the machining efficiency of the figuring process. The verification experiments are accomplished on our experimental installation to validate the feasibility of the IBA method. First, a fused silica sample with a rectangular pit defect is figured by using IBA. Through two iterations within only 47.5 min, this highly steep pit is effectively corrected, and the surface error is improved from the original 24.69 nm root mean square (RMS) to the final 3.68 nm RMS. Then another experiment is carried out to demonstrate the correcting capability of IBA for mid-to-high spatial frequency surface errors, and the final results indicate that the surface accuracy and surface quality can be simultaneously improved.

Interior and Ejecta Morphologies of Impact Craters on Ganymede

NASA Astrophysics Data System (ADS)

Barlow, Nadine G.; Klaybor, K.; Katz-Wigmore, J.

2006-09-01

We are utilizing Galileo SSI imagery of Ganymede to classify impact crater interior and ejecta morphologies. Although we are in the early stages of compiling our Catalog of Impact Craters on Ganymede, some interesting trends are beginning to emerge. Few craters display obvious ejecta morphologies, but 68 craters are classified as single layer ejecta and 3 as double layer ejecta. We see no obvious correlation of layered ejecta morphologies with terrain or latitude. All layered ejecta craters have diameters between 10 and 40 km. Sinuosity ("lobateness") and ejecta extent ("ejecta mobility ratio") of Ganymede layered ejecta craters are lower than for martian layered ejecta craters. This suggests less mobility of ejecta materials on Ganymede, perhaps due to the colder temperatures. Interior structures being investigated include central domes, peaks, and pits. 57 dome craters, 212 central peak craters, and 313 central pit craters have been identified. Central domes occur in 50-100 km diameter craters while peaks are found in craters between 20 and 50 km and central pit craters range between 29 and 74 km in diameter. The Galileo Regio region displays higher concentrations of central dome and central pit craters than other regions we have investigated. 67% of central pit craters studied to date are small pits, where the ratio of pit diameter to crater diameter is <0.2. Craters containing the three interior structures preferentially occur on darker terrain units, suggesting that an ice-silicate composition is more conducive to interior feature formation than pure ice alone. Results of this study have important implications not only for the formation of specific interior and ejecta morphologies on Ganymede but also for analogous features associated with Martian impact craters. This research is funded through NASA Outer Planets Research Program Award #NNG05G116G to N. G. Barlow.

Defect mapping system

DOEpatents

Sopori, Bhushan L.

1995-01-01

Apparatus for detecting and mapping defects in the surfaces of polycrystalline materials in a manner that distinguishes dislocation pits from grain boundaries includes a laser for illuminating a wide spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate rastor mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities.

Defect mapping system

DOEpatents

Sopori, B.L.

1995-04-11

Apparatus for detecting and mapping defects in the surfaces of polycrystalline materials in a manner that distinguishes dislocation pits from grain boundaries includes a laser for illuminating a wide spot on the surface of the material, a light integrating sphere with apertures for capturing light scattered by etched dislocation pits in an intermediate range away from specular reflection while allowing light scattered by etched grain boundaries in a near range from specular reflection to pass through, and optical detection devices for detecting and measuring intensities of the respective intermediate scattered light and near specular scattered light. A center blocking aperture or filter can be used to screen out specular reflected light, which would be reflected by nondefect portions of the polycrystalline material surface. An X-Y translation stage for mounting the polycrystalline material and signal processing and computer equipment accommodate rastor mapping, recording, and displaying of respective dislocation and grain boundary defect densities. A special etch procedure is included, which prepares the polycrystalline material surface to produce distinguishable intermediate and near specular light scattering in patterns that have statistical relevance to the dislocation and grain boundary defect densities. 20 figures.

Directed self-assembly of metal oxide quantum dots: Copper oxide on strontium titanium trioxide

NASA Astrophysics Data System (ADS)

Du, Yingge

2007-12-01

This dissertation explores the use of focused ion-beams (FIB) to direct the self-assembly of Cu2O quantum dots (QDs) on SrTiO3 (100) substrates via point implants of Ga+ at 30 keV After Ga+ implant and subsequent chemical and thermal surface preparation, oxygen plasma-assisted molecular beam-epitaxy (OPA-MBE) is used to grow Cu 2O QDs. The research of this dissertation finds that, for high FIB implant dose (5.6x1018 ions/cm2) and large interdot spacing (1000 nm), multiple QDs can be formed preferentially on the edges of FIB modified pits. For lower doses and/or smaller interdot spacings (8.8x1014 ions/cm2 and lower, 130 or 167 nm), individual QDs nucleate first within the pits. Under carefully controlled conditions, the separation and arrangement of the Cu2O QDs follows the FIB patterned template. This study finds that the FIB directed self-assembly technique works for different FIB doses, FIB interdot spacings and OPA-MBE deposition thicknesses, suggesting that this method is robust and flexible. Examination of QD growth on low-dose implant surfaces revealed a multi-step growth process. Initial deposition filled the pits just to the level of the original unmodified crystal growth surface. Following a pause in QD growth and the deposition of additional material, QD growth resumed on top of these perfectly filled pits. As growth continued, the dots reached a self-limiting size such that additional material deposition generated more QDs of similar size rather than continued growth of the large dots. This dissertation also seeks to increase understanding of the relative rolls played in the directed self-assembly process by local substrate chemistry, surface morphology, crystal-linity, and stress/strain. Experimental results revealed that although Ga concentration was noticeably higher on modified regions after FIB implant, no measurable Ga was found on the surface after high temperature annealing performed prior to QD growth. Thus Ga related chemistry/reactivity changes appear unlikely to be primary motivators of directed self-assembly. Low dose implant patterning created local depressions on the surface. This pit shape topography appears to be a strong contributor to the preferred nucleation within the pits, as the sidewalls of those surface pits could contain a high density of surface steps, which are known to decrease the adatom diffusion length and act as sinks to absorb the diffusing species. To further interpret the low dose implant results, calculations of total free-energy changes have been performed to study the differences between nucleation on a flat substrate surface and nucleation within a surface pit. This analysis shows that nucleation within a pit is almost always energetically favorable. In some special cases, assuming the pits have an inverted pyramidal shape, calculations show that island formation within the pits lowers the system total free-energy from the beginning of growth, i.e. there is no critical radius or energy barrier before a stable nucleus can be formed. The major geometric difference between high and low dose implantation area was revealed by AFM studies, which showed that pits generated by high implantation dose were still rounded after annealing and before growth, while pits from lower doses patterning had developed square edges oriented along the <100> directions of the substrate. These geometric differences suggest differences in crystalline or strain/stress states, either/both of which could have caused the subsequent different island growth characteristics. Continued study of directed self-assembly of metal oxide quantum dots should lead to better understanding of the creation of well ordered, precisely controlled, high density QD arrays, ultimately contributing to the development of next generation nanoelectronic, magnetic, and optical devices.

Excavating and loading equipment for peat mining

NASA Astrophysics Data System (ADS)

Mikhailov, A. V.; Zhigulskaya, A. I.; Yakonovskaya, T. B.

2017-10-01

Recently, the issues of sustainable development of Russian regions, related to ensuring energy security, are more urgent than ever. To achieve sustainable development, an integrated approach to the use of local natural resources is needed. Practically in all north regions of the Russian Federation, peat as a local natural resource is widespread, which has a practical application in the area of housing services. The paper presents the evaluation of technologies for open-pit peat mining, as well as analysis of technological equipment for peat production. Special attention is paid to a question of peat materials excavating and loading. The problem of equipment selection in a peat surface mine is complex. Many features, restrictions and criteria need to be considered. Use of low and ultra-low ground pressure excavators and low ground pressure front-end loaders with full-range tires to provide the necessary floatation in the peat bog environment is offered.

View west from USFS Road 369 toward Fowler Lode Adit ...

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

View west from USFS Road 369 toward Fowler Lode Adit and O'Brien Ditch (left) and open-pit excavation (top-center, beyond trees); ridge saddle is in center - Steamboat Mine, Southeast slope of Steamboat Mountain, west of the junction of Forest Service Roads 1000300 and 1000365, Jacksonville, Jackson County, OR

Study of application of ERTS-1 imagery to fracture-related mine safety hazards in the coal mining industry

NASA Technical Reports Server (NTRS)

Wier, C. E. (Principal Investigator); Wobber, F. J. (Principal Investigator); Russell, O. R.; Amato, R. V.

1972-01-01

The author has identified the following significant results. Numerous fractures are identifiable on the 1:120,000 color infrared photography. Some of these fractures are in the proximity of operating open pit mines and should provide opportunities for field checking and confirmation.

76 FR 52688 - Notice of Intent To Prepare an Environmental Impact Statement for the Sheep Mountain Uranium...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-23

... project employing open pit and underground mining methods and using heap leach methods for uranium...] Notice of Intent To Prepare an Environmental Impact Statement for the Sheep Mountain Uranium Project... comments regarding issues and resource information for the proposed Sheep Mountain Uranium Project (the...

Influence of etching time and bonding strategies on the microshear bond strength of self- and light-cured pit-and-fissure sealants.

PubMed

Souza-Junior, Eduardo José; Borges, Boniek Castillo Dutra; Montes, Marcos Antônio Japiassú Resende; Alonso, Roberta Caroline Bruschi; Ambrosano, Glaucia Maria Bovi; Sinhoreti, Mário Alexandre Coelho

2012-01-01

This study evaluated the impact of extended etching and bonding strategies on the microshear bond strength of three sealant materials. Two pit-and-fissure sealants [FluroShield, Dentsply (light-cured) and AlphaSeal, DFL (self-cured)] and one light-cured flowable composite resin (Permaflo, Ultradent) were evaluated according to different enamel etching times (15 s or 30 s) and bonding procedures (no adhesive application, application of primer/hydrophobic resin or hydrophobic resin only). Intact enamel blocks were obtained from bovine teeth and sealed via the tested protocols. After 24 h, the microshear bond strength test was performed in a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were classified by stereomicroscopy. Data were submitted to a three-way ANOVA and to Tukey's test (α=0.05). There was no statistically significant difference (p>0.05) among the materials. Permaflo showed higher bond strength when etched for 30 s alone. Enamel overetching decreased the bond strength of the light-cured sealant. Primer/bond previous treatment improved bond performance for AlphaSeal. In conclusion, from the tested conditions, all sealant materials presented similar bond strength values in relation to bonding protocol and etching time. The flowable composite can be used as a pit-and-fissure sealant. The use of a three-step adhesive system was essential for the self-cured sealant application.

High efficiency, low cost, thin film silicon solar cell design and method for making

DOEpatents

Sopori, Bhushan L.

2001-01-01

A semiconductor device having a substrate, a conductive intermediate layer deposited onto said substrate, wherein the intermediate layer serves as a back electrode, an optical reflector, and an interface for impurity gettering, and a semiconductor layer deposited onto said intermediate layer, wherein the semiconductor layer has a grain size at least as large as the layer thickness, and preferably about ten times the layer thickness. The device is formed by depositing a metal layer on a substrate, depositing a semiconductive material on the metal-coated substrate to produce a composite structure, and then optically processing the composite structure by illuminating it with infrared electromagnetic radiation according to a unique time-energy profile that first produces pits in the backside surface of the semiconductor material, then produces a thin, highly reflective, low resistivity alloy layer over the entire area of the interface between the semiconductor material and the metal layer, and finally produces a grain-enhanced semiconductor layer. The time-energy profile includes increasing the energy to a first energy level to initiate pit formation and create the desired pit size and density, then ramping up to a second energy level in which the entire device is heated to produce an interfacial melt, and finally reducing the energy to a third energy level and holding for a period of time to allow enhancement in the grain size of the semiconductor layer.

High efficiency low cost thin film silicon solar cell design and method for making

DOEpatents

Sopori, Bhushan L.

1999-01-01

A semiconductor device having a substrate, a conductive intermediate layer deposited onto said substrate, wherein the intermediate layer serves as a back electrode, an optical reflector, and an interface for impurity gettering, and a semiconductor layer deposited onto said intermediate layer, wherein the semiconductor layer has a grain size at least as large as the layer thickness, and preferably about ten times the layer thickness. The device is formed by depositing a metal layer on a substrate, depositing a semiconductive material on the metal-coated substrate to produce a composite structure, and then optically processing the composite structure by illuminating it with infrared electromagnetic radiation according to a unique time-energy profile that first produces pits in the backside surface of the semiconductor material, then produces a thin, highly reflective, low resistivity alloy layer over the entire area of the interface between the semiconductor material and the metal layer, and finally produces a grain-enhanced semiconductor layer. The time-energy profile includes increasing the energy to a first energy level to initiate pit formation and create the desired pit size and density, then ramping up to a second energy level in which the entire device is heated to produce an interfacial melt, and finally reducing the energy to a third energy level and holding for a period of time to allow enhancement in the grain size of the semiconductor layer.

The study of aluminium anodes for high power density Al/air batteries with brine electrolytes

NASA Astrophysics Data System (ADS)

Nestoridi, Maria; Pletcher, Derek; Wood, Robert J. K.; Wang, Shuncai; Jones, Richard L.; Stokes, Keith R.; Wilcock, Ian

Aluminium alloys containing small additions of both tin (∼0.1 wt%) and gallium (∼0.05 wt%) are shown to dissolve anodically at high rates in sodium chloride media at room temperatures; current densities >0.2 A cm -2 can be obtained at potentials close to the open circuit potential, ∼-1500 mV versus SCE. The tin exists in the alloys as a second phase, typically as ∼1 μm inclusions (precipitates) distributed throughout the aluminium structure, and anodic dissolution occurs to form pits around the tin inclusions. Although the distribution of the gallium in the alloy could not be established, it is also shown to be critical in the formation of these pits as well as maintaining their activity. The stability of the alloys to open circuit corrosion and the overpotential for high rate dissolution, both critical to battery performance, are shown to depend on factors in addition to elemental composition; both heat treatment and mechanical working influence the performance of the alloy. The correlation between alloy performance and their microstructure has been investigated.

Typical whole body vibration exposure magnitudes encountered in the open pit mining industry.

PubMed

Howard, Bryan; Sesek, Richard; Bloswick, Don

2009-01-01

According to recent research, a causal link has been established between occupational exposure to whole body vibration and an increased occurrence of low back pain. To aid in the further development of an in-house health and safety program for a large open pit mining facility interested in reducing back pain among its operators, whole body vibration magnitudes were characterized for a range of jobs. Specifically, thirty-five individual jobs from five different areas across the facility were evaluated for tri-axial acceleration levels during normal operating conditions. Tri-axial acceleration magnitudes were categorized into thirteen job groups. Job groups were ranked according to exposure and compared to the ISO 2631-1 standard for health risk assessment. Three of the thirteen job groups produced tri-axial acceleration magnitudes below the ISO 2631-1 low/moderate health caution limit for a twelve hour exposure. Six of the thirteen job groups produced exposures within the moderate health risk range. Four job groups were found to subject operators to WBV acceleration magnitudes above the moderate/high health caution limit.

Short-term scheduling of an open-pit mine with multiple objectives

NASA Astrophysics Data System (ADS)

Blom, Michelle; Pearce, Adrian R.; Stuckey, Peter J.

2017-05-01

This article presents a novel algorithm for the generation of multiple short-term production schedules for an open-pit mine, in which several objectives, of varying priority, characterize the quality of each solution. A short-term schedule selects regions of a mine site, known as 'blocks', to be extracted in each week of a planning horizon (typically spanning 13 weeks). Existing tools for constructing these schedules use greedy heuristics, with little optimization. To construct a single schedule in which infrastructure is sufficiently utilized, with production grades consistently close to a desired target, a planner must often run these heuristics many times, adjusting parameters after each iteration. A planner's intuition and experience can evaluate the relative quality and mineability of different schedules in a way that is difficult to automate. Of interest to a short-term planner is the generation of multiple schedules, extracting available ore and waste in varying sequences, which can then be manually compared. This article presents a tool in which multiple, diverse, short-term schedules are constructed, meeting a range of common objectives without the need for iterative parameter adjustment.

Questa Baseline and Pre-mining Ground-Water Quality Investigation, 7. A Pictorial Record of Chemical Weathering, Erosional Processes, and Potential Debris-flow Hazards in Scar Areas Developed on Hydrothermally Altered Rocks

USGS Publications Warehouse

Plumlee, Geoffrey S.; Ludington, Steve; Vincent, Kirk R.; Verplanck, Philip L.; Caine, Jonathan S.; Livo, K. Eric

2009-01-01

Erosional scar areas developed along the lower Red River basin, New Mexico, reveal a complex natural history of mineralizing processes, rapid chemical weathering, and intense physical erosion during periodic outbursts of destructive, storm-induced runoff events. The scar areas are prominent erosional features with craggy headwalls and steep, denuded slopes. The largest scar areas, including, from east to west, Hottentot Creek, Straight Creek, Hansen Creek, Lower Hansen Creek, Sulfur Gulch, and Goat Hill Gulch, head along high east-west trending ridges that form the northern and southern boundaries of the lower Red River basin. Smaller, topographically lower scar areas are developed on ridge noses in the inner Red River valley. Several of the natural scar areas have been modified substantially as a result of large-scale open-pit and underground mining at the Questa Mine; for example, much of the Sulfur Gulch scar was removed by open pit mining, and several scars are now partially or completely covered by mine waste dumps.

Geology of the fushun coalfield, Liaoning Province, People's Republic of China

USGS Publications Warehouse

Johnson, E.A.

1990-01-01

The Fushun coalfield is located in Liaoning Province 45 km east of Shenyang in a relatively small east-west-trending exposure of Mesozoic and Cenozoic rocks surrounded by Precambrian terrane. The coal is included in a sequence of early Tertiary rocks consisting of Paleocene basalt and tuff, and Eocene coal, oil shale and mudstone. These units have been folded into a syncline that plunges gently to the east. The overturned north limb of this fold has been partly removed by a thrust fault. The principal coal beds are low-sulfur subbituminous and bituminous in rank, are of limnic origin, and are contained in the 55-m-thick Eocene Guchengzi Formation. The field, which has been active since the turn of the century, has both open pit and underground mines. The largest operation is the West Open Pit mine, which measures 2.0 km wide, 6.6 km long, and 300 m deep. Coal is mined by means of power shovels, trucks, and an electric rail system. Oil shale from the Eocene Jijuntun Formation is also mined. ?? 1990.

Incubation pit analysis and calculation of the hydrodynamic impact pressure from the implosion of an acoustic cavitation bubble.

PubMed

Tzanakis, I; Eskin, D G; Georgoulas, A; Fytanidis, D K

2014-03-01

An experimental study to evaluate cavitation bubble dynamics is conducted. The aim is to predict the magnitude and statistical distribution of hydrodynamic impact pressure generated from the implosion of various individual acoustic cavitation bubbles near to a rigid boundary, considering geometrical features of the pitted area. A steel sample was subjected to cavitation impacts by an ultrasonic transducer with a 5mm diameter probe. The pitted surface was then examined using high-precision 3D optical interferometer techniques. Only the incubation period where surface is plastically deformed without material loss is taken into account. The exposure time was adjusted in the range of 3-60 s to avoid pit overlapping and a special procedure for pit analysis and characterisation was then followed. Moreover, a high-speed camera device was deployed to capture the implosion mechanisms of cavitation bubbles near to the surface. The geometrical characteristics of single incubation pits as well as pit clusters were studied and their deformation patterns were compared. Consequently, a reverse engineering approach was applied in order the hydrodynamic impact pressure from the implosion of an individual cavitation bubble to be determined. The characteristic parameters of the cavitation implosion process such as hydrodynamic impact pressure and liquid micro-jet impact velocity as well as the hydrodynamic severity of the cavitation impacts were quantified. It was found that the length of the hypotenuse of the orthographic projections from the center of the pit, which basically represents the deformed area of the pit, increases with the hydrodynamic impact aggressiveness in a linear rate. Majority of the hydrodynamic impacts were in the range of 0.4-1 GPa while the corresponding micro-jet velocities were found to be in the range of 200-700 m/s. Outcomes of this study, contribute to further understanding the cavitation intensity from the implosion of acoustically generated bubbles and could certainly represent a significant step towards developing more accurate cavitation models. Copyright © 2013 Elsevier B.V. All rights reserved.

Neutralisation of an acidic pit lake by alkaline waste products.

PubMed

Allard, Bert; Bäckström, Mattias; Karlsson, Stefan; Grawunder, Anja

2014-01-01

A former open pit where black shale (alum shale) was excavated during 1942-1965 has been water filled since 1966. The water chemistry was dominated by calcium and sulphate and had a pH of 3.2-3.4 until 1997-1998, when pH was gradually increasing. This was due to the intrusion of leachates from alkaline cement waste deposited close to the lake. A stable pH of around 7.5 was obtained after 6-7 years. The chemistry of the pit lake has changed due to the neutralisation. Concentrations of some dissolved metals, notably zinc and nickel, have gone down, as a result of adsorption/co-precipitation on solid phases (most likely iron and aluminium hydroxides), while other metals, notably uranium and molybdenum, are present at elevated levels. Uranium concentration is reaching a minimum of around pH 6.5 and is increasing at higher pH, which may indicate a formation of neutral and anionic uranyl carbonate species at high pH (and total carbonate levels around 1 mM). Weathering of the water-exposed shale is still in progress.

Influence of aggressive ions on the degradation behavior of biomedical magnesium alloy in physiological environment.

PubMed

Xin, Yunchang; Huo, Kaifu; Tao, Hu; Tang, Guoyi; Chu, Paul K

2008-11-01

Various electrochemical approaches, including potentiodynamic polarization, open circuit potential evolution and electrochemical impedance spectroscopy (EIS), are employed to investigate the degradation behavior of biomedical magnesium alloy under the influence of aggressive ions, such as chloride, phosphate, carbonate and sulfate, in a physiological environment. The synergetic effects and mutual influence of these ions on the degradation behavior of Mg are revealed. Our results demonstrate that chloride ions can induce porous pitting corrosion. In the presence of phosphates, the corrosion rate decreases and the formation of pitting corrosion is significantly delayed due to precipitation of magnesium phosphate. Hydrogen carbonate ions are observed to stimulate the corrosion of magnesium alloy during the early immersion stage but they can also induce rapid passivation on the surface. This surface passivation behavior mainly results from the fast precipitation of magnesium carbonate in the corrosion product layer that can subsequently inhibit pitting corrosion completely. Sulfate ions are also found to stimulate magnesium dissolution. These results improve our understanding on the degradation mechanism of surgical magnesium in the physiological environment.

A New Platform for Investigating In-Situ NIR Reflectance in Snow

NASA Astrophysics Data System (ADS)

Johnson, M.; Taubenheim, J. R. L.; Stevenson, R.; Eldred, D.

2017-12-01

In-situ near infrared (NIR) reflectance measurements of the snowpack have been shown to have correlations to valuable snowpack properties. To-date many studies take these measurements by digging a pit and setting up a NIR camera to take images of the wall. This setup is cumbersome, making it challenging to investigate things like spatial variability. Over the course of 3 winters, a new device has been developed capable of mitigating some of the downfalls of NIR open pit photography. This new instrument is a NIR profiler capable of taking NIR reflectance measurements without digging a pit, with most measurements taking less than 30 seconds to retrieve data. The latest prototype is built into a ski pole and automatically transfers data wirelessly to the users smartphone. During 2016-2017 winter, the device was used by 37 different users resulting in over 4000 measurements in the Western United States, demonstrating a dramatic reduction in time to data when compared to other methods. Presented here are some initial findings from a full winter of using the ski pole version of this device.

Performance of OTEC Heat Exchanger Materials in Tropical Seawaters

NASA Astrophysics Data System (ADS)

Larsen-Basse, Jorn

1985-03-01

The corrosion of several aluminum alloys in flowing Hawaiian surface seawater and water from 600 m depth for exposure periods up to three years has been studied. The alloys tested in cold water were Alclad (7072) 3003 and 3004; and bare 3004 and 5052). All show some pitting. Pit growth is slow, and pits do not penetrate the cladding. In the warm water, only uniform corrosion has been found. All alloys corrode at the same, low rate of˜3 μm/year after an initial short period of more rapid corrosion. This behavior is closely linked to the formation of a protective inorganic scale film on the surface. It consists of precipitated scale minerals from the seawater and aluminum corrosion products. The results indicate that OTEC evaporator heat exchangers constructed of aluminum alloys should have acceptable service lives.

Long term storage test of titanium material with liquid fluorine propellant

NASA Technical Reports Server (NTRS)

Denson, J. R.; English, W. D.; Roth, J.; Toy, A.

1979-01-01

The compatibility of 6AL-4V Ti with propellant grade GF2 and LF2 at 77 K for up to 3 years was investigated. Titanium double coupons, annealed or heat treated, with 16 or 64 RMS finishes, were immersed in F2 in individual Pyrex capsules and stored under LN2 for 29 and 39 months. Pre and post immersion tests were performed on the propellant and coupons. Chemical analysis of the propellant did not reveal any significant changes due to titanium corrosion. Gravimetric, visual, microscopic, and metallurgical examination with pitting analysis did not reveal gross corrosion of the titanium although pitting appears to be greater after 39 months exposure. The increase in pit size and number raises the possibility of unpredictable crack propagation instability. Fracture toughness tests are necessary to define this possibility.

Lunar metallic particle ("mini-moon"): An interpretation

USGS Publications Warehouse

McKay, D.S.; Carter, J.L.; Greenwood, W.R.

1971-01-01

A troilite-rich nickel-iron particle ("mini-moon") recovered from the moon may be a mound detached from a sphere of silicate glass. Erosion and pitting of the particle may have been caused by passage through a cloud of hot gas and particulate matter formed by meteorite impact on the lunar surface. This explanation is in contrast to the theory that the particle was meteoritically derived molten material that was furrowed during solidification after lunar impact, subsequently pitted by high-velocity particles, and then abraded and polished by drifting dust while on the lunar surface.

Hyperspectral analysis for qualitative and quantitative features related to acid mine drainage at a remediated open-pit mine

NASA Astrophysics Data System (ADS)

Davies, G.; Calvin, W. M.

2015-12-01

The exposure of pyrite to oxygen and water in mine waste environments is known to generate acidity and the accumulation of secondary iron minerals. Sulfates and secondary iron minerals associated with acid mine drainage (AMD) exhibit diverse spectral properties in the ultraviolet, visible and near-infrared regions of the electromagnetic spectrum. The use of hyperspectral imagery for identification of AMD mineralogy and contamination has been well studied. Fewer studies have examined the impacts of hydrologic variations on mapping AMD or the unique spectral signatures of mine waters. Open-pit mine lakes are an additional environmental hazard which have not been widely studied using imaging spectroscopy. A better understanding of AMD variation related to climate fluctuations and the spectral signatures of contaminated surface waters will aid future assessments of environmental contamination. This study examined the ability of multi-season airborne hyperspectral data to identify the geochemical evolution of substances and contaminant patterns at the Leviathan Mine Superfund site. The mine is located 24 miles southeast of Lake Tahoe and contains remnant tailings piles and several AMD collection ponds. The objectives were to 1) distinguish temporal changes in mineralogy at a the remediated open-pit sulfur mine, 2) identify the absorption features of mine affected waters, and 3) quantitatively link water spectra to known dissolved iron concentrations. Images from NASA's AVIRIS instrument were collected in the spring, summer, and fall seasons for two consecutive years at Leviathan (HyspIRI campaign). Images had a spatial resolution of 15 meters at nadir. Ground-based surveys using the ASD FieldSpecPro spectrometer and laboratory spectral and chemical analysis complemented the remote sensing data. Temporal changes in surface mineralogy were difficult to distinguish. However, seasonal changes in pond water quality were identified. Dissolved ferric iron and chlorophyll-a concentrations were determined to be the major influences on pond water spectral variation.

Assessment of the natural sources of particulate matter on the opencast mines air quality.

PubMed

Huertas, J I; Huertas, M E; Cervantes, G; Díaz, J

2014-09-15

Particulate matter is the main air pollutant in open pit mining areas. Preferred models that simulate the dispersion of the particles have been used to assess the environmental impact of the mining activities. Results obtained through simulation have been compared with the particle concentration measured in several sites and a coefficient of determination R(2)<0.78 has been reported. This result indicates that in the open pit mining areas there may be additional sources of particulate matter that have not been considered in the modeling process. This work proposes that the unconsidered sources of emissions are of regional scope such as the re-suspension particulate matter due to the wind action over uncovered surfaces. Furthermore, this work proposes to estimate the impact of such emissions on air quality as a function of the present and past meteorological conditions. A statistical multiple regression model was implemented in one of the world's largest open pit coal mining regions which is located in northern Colombia. Data from 9 particle-concentration monitoring stations and 3 meteorological stations obtained from 2009 to 2012 were statistically compared. Results confirmed the existence of a high linear relation (R(2)>0.95) between meteorological variables and particulate matter concentration being humidity, humidity of the previous day and temperature, the meteorological variables that contributed most significantly in the variance of the particulate matter concentration measured in the mining area while the contribution of the AERMOD estimations to the short term TSP (Total Suspended Particles) measured concentrations was negligible (<5%). The multiple regression model was used to identify the meteorological condition that leads to pollution episodes. It was found that conditions drier than 54% lead to pollution episodes while humidities greater than 70% maintain safe air quality conditions in the mining region in northern Colombia. Copyright © 2014 Elsevier B.V. All rights reserved.

Gullies and Voids

NASA Image and Video Library

2018-02-05

Intricate gullies have formed on the northern wall of this impact crater located in the Terra Cimmeria region in this image from NASA's Mars Reconnaissance Orbiter (MRO). This crater may have formed in a region rich in ground water. This ground water likely flowed down the wall, eventually eroding numerous gullies while carrying sediments to form fan deposits. Ultimately the water likely infiltrated and froze beneath the surface. Other hypotheses say gullies form through carbon dioxide frost avalanches that we can see today. What about this chain of pits snaking their way downhill? After material was transported, subsurface voids may have formed, removing support for the overlying material. The collapse of the surface into the cavities below likely resulted in the pits and troughs, perhaps beginning a new cycle of gully formation. https://photojournal.jpl.nasa.gov/catalog/PIA22239

Endurance and failure characteristics of modified Vasco X-2, CBS 600 and AISI 9310 spur gears. [aircraft construction materials

NASA Technical Reports Server (NTRS)

Townsend, D. P.; Zaretsky, E. V.

1980-01-01

Gear endurance tests and rolling-element fatigue tests were conducted to compare the performance of spur gears made from AISI 9310, CBS 600 and modified Vasco X-2 and to compare the pitting fatigue lives of these three materials. Gears manufactured from CBS 600 exhibited lives longer than those manufactured from AISI 9310. However, rolling-element fatigue tests resulted in statistically equivalent lives. Modified Vasco X-2 exhibited statistically equivalent lives to AISI 9310. CBS 600 and modified Vasco X-2 gears exhibited the potential of tooth fracture occurring at a tooth surface fatigue pit. Case carburization of all gear surfaces for the modified Vasco X-2 gears results in fracture at the tips of the gears.

Mobile Pit verification system design based on passive special nuclear material verification in weapons storage facilities

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

Paul, J. N.; Chin, M. R.; Sjoden, G. E.

2013-07-01

A mobile 'drive by' passive radiation detection system to be applied in special nuclear materials (SNM) storage facilities for validation and compliance purposes has been designed through the use of computational modeling and new radiation detection methods. This project was the result of work over a 1 year period to create optimal design specifications to include creation of 3D models using both Monte Carlo and deterministic codes to characterize the gamma and neutron leakage out each surface of SNM-bearing canisters. Results were compared and agreement was demonstrated between both models. Container leakages were then used to determine the expected reactionmore » rates using transport theory in the detectors when placed at varying distances from the can. A 'typical' background signature was incorporated to determine the minimum signatures versus the probability of detection to evaluate moving source protocols with collimation. This established the criteria for verification of source presence and time gating at a given vehicle speed. New methods for the passive detection of SNM were employed and shown to give reliable identification of age and material for highly enriched uranium (HEU) and weapons grade plutonium (WGPu). The finalized 'Mobile Pit Verification System' (MPVS) design demonstrated that a 'drive-by' detection system, collimated and operating at nominally 2 mph, is capable of rapidly verifying each and every weapon pit stored in regularly spaced, shelved storage containers, using completely passive gamma and neutron signatures for HEU and WGPu. This system is ready for real evaluation to demonstrate passive total material accountability in storage facilities. (authors)« less

The sanitation situation: a case study.

PubMed

Ali, S

1993-10-15

In India, interviews with and observations of members of 100 households with a latrine were done in the towns of Satna and Khandwa, in Madhya Pradesh State, to examine the sanitation situation, to evaluate the maintenance and performance of the 2 pit pour-flush water seal (PF) latrines of poor households, and to recommend actions to improve the sanitation situation. The upper caste Hindus and Muslims tended to use the PF latrines, while the low caste Hindus tended not to use them. Few dry latrines existed in Satna. More than 75% of the households used the PF latrines, especially in Khandwa. The latrines generally were in disrepair, because more families did not receive either instruction or back-up latrine maintenance. Other apparent reasons for poor maintenance were limited water, illiteracy, limited knowledge of how the PF latrine works, poor construction, excreta adhering to the squatting pan, rain entering the leach pits through the squatting pan causing overflow of the pits contents, clogged outlets and Y-junctions, difficulty in emptying the pits, and collapsed brick drains. Children did not use the latrines in more than 50% of households were the latrines were used. Uncomfortable seats were the reason the children chose to defecate in the open. These findings led the author to recommend that the government adopt laws addressing sanitation in low-cost housing settlements, slums, and other areas. A PF latrine must be constructed for each new building. Dry or bucket latrines must be connected to sewers, if available. Leach pits must be constructed for converting latrines into PF latrines. There should be a ban on new dry or bucket latrines. The government should provide the local authorities the power to enforce these regulations. PF latrines should be free for the poor.

STS-32 crewmembers use water hoses during fire fighting training at JSC

NASA Image and Video Library

1989-09-22

STS-32 crewmembers use water hoses during fire fighting exercises at JSC's Fire Training Pit across from the Gilruth Center Bldg 207. Mission Specialist (MS) G. David Low with nozzle open directs water into the fire as fire/ security personnel coaches and instructs him on his attempt to extinguish the blaze. MS Bonnie J. Dunbar maneuvers the hose behind Low. A second group of crewmembers alongside Low and Dunbar, MS Marsha S. Ivins, holding hose nozzle, Commander Daniel C. Brandenstein, and Pilot James D. Wetherbee position themselves before opening hose nozzle.

STS-32 crewmembers use water hoses during fire fighting training at JSC

NASA Technical Reports Server (NTRS)

1989-01-01

STS-32 crewmembers use water hoses during fire fighting exercises at JSC's Fire Training Pit across from the Gilruth Center Bldg 207. Mission Specialist (MS) G. David Low with nozzle open directs water into the fire as fire/ security personnel coaches and instructs him on his attempt to extinguish the blaze. MS Bonnie J. Dunbar maneuvers the hose behind Low. A second group of crewmembers alongside Low and Dunbar, MS Marsha S. Ivins, holding hose nozzle, Commander Daniel C. Brandenstein, and Pilot James D. Wetherbee position themselves before opening hose nozzle.

Apollo 12 Lunar Module exhaust plume impingement on Lunar Surveyor III

NASA Astrophysics Data System (ADS)

Immer, Christopher; Metzger, Philip; Hintze, Paul E.; Nick, Andrew; Horan, Ryan

2011-02-01

Understanding plume impingement by retrorockets on the surface of the Moon is paramount for safe lunar outpost design in NASA's planned return to the Moon for the Constellation Program. Visual inspection, Scanning Electron Microscopy, and surface scanned topology have been used to investigate the damage to the Lunar Surveyor III spacecraft that was caused by the Apollo 12 Lunar Module's close proximity landing. Two parts of the Surveyor III craft returned by the Apollo 12 astronauts, Coupons 2050 and 2051, which faced the Apollo 12 landing site, show that a fine layer of lunar regolith coated the materials and was subsequently removed by the Apollo 12 Lunar Module landing rocket. The coupons were also pitted by the impact of larger soil particles with an average of 103 pits/cm 2. The average entry size of the pits was 83.7 μm (major diameter) × 74.5 μm (minor diameter) and the average estimated penetration depth was 88.4 μm. Pitting in the surface of the coupons correlates to removal of lunar fines and is likely a signature of lunar material imparting localized momentum/energy sufficient to cause cracking of the paint. Comparison with the lunar soil particle size distribution and the optical density of blowing soil during lunar landings indicates that the Surveyor III spacecraft was not exposed to the direct spray of the landing Lunar Module, but instead experienced only the fringes of the spray of soil. Had Surveyor III been exposed to the direct spray, the damage would have been orders of magnitude higher.

75 FR 21343 - Notice of Availability of the Final Environmental Impact Statement for the Round Mountain...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-23

... INFORMATION: The Round Mountain Gold Corporation, which is a joint venture of Kinross Gold Corporation and Barrick Gold Corporation, proposes to expand its Round Mountain Mine, an existing open-pit gold mining and... about 66.2 acres between the Round Mountain area and the Gold Hill area. The primary method of...

78 FR 7808 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Buffalo Valley...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-04

... amended, the Bureau of Land Management (BLM) Mount Lewis Field Office, Battle Mountain, Nevada, intends to... Buffalo Valley Mine Project, a proposed open pit gold mine, mill, and associated facilities, located on..._mountain_field.html . In order to be considered during the preparation of the Draft EIS, all comments must...

Farewell to Alexandria: Solutions to Space, Growth, and Performance Problems of Libraries.

ERIC Educational Resources Information Center

Gore, Daniel, Ed.

All of the contributions in this volume, except the last, were presented at a conference sponsored by the Associated Colleges of the Midwest, held in Chicago, April 17-18, 1975. Entitled "Touching Bottom in the Bottomless Pit," the conference was intended to open a national debate on space, growth, and performance problems of…

78 FR 70067 - Notice of Availability of the Final Environmental Impact Statement for the Proposed Pan Mine...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-22

..._programs/minerals/mining_projects/pan_mine_project.html . FOR FURTHER INFORMATION CONTACT: Miles Kreidler...: Midway Gold US, Inc. (Midway) proposes to construct and operate an open-pit gold mining operation in the... years, which includes 13 years of mining and additional time for associated construction, closure, and...

Validation of Airborne Visible-Infrared Imaging Spectrometer Data at Ray Mine, AZ

NASA Technical Reports Server (NTRS)

Lang, H.; Baloga, S.

1999-01-01

We validate 1997 Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) reflectance spectra covering 0.4 meu - 2.4 meu from a stable, flat mineralogically characterized man-made target at Ray Mine, AZ, the site for an EPA/NASA assessment of the utility of remote sensing for monitoring acid drainage from an active open pit mine.

COMPARISON OF DATA FROM SYNTHETIC LEACHATE AND DIRECT SAMPLING OF ACID DRAINAGE FROM MINE WASTES: IMPLICATIONS FOR MERCURY TRANSPORT AND WASTE MANAGEMENT

EPA Science Inventory

The Sulphur Bank Mercury Mine (SBMM) in Lake County, California operated from the 1860s through the 1950's. Mining for sulfur started with surface operations and progressed to shaft, then open pit techniques to obtain mercury. Mining has resulted in deposition of approximately ...

40 CFR 440.33 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2012 CFR

2012-07-01

...) The concentration of pollutants discharged in mine drainage from mines, either open-pit or underground, that produce uranium ore, including mines using in-situ leach methods, shall not exceed: Effluent...). Except as provided in subpart L of this part and 40 CFR 125.30 through 125.32, any existing point source...

40 CFR 440.33 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

... concentration of pollutants discharged in mine drainage from mines, either open-pit or underground, that produce uranium ore, including mines using in-situ leach methods, shall not exceed: Effluent characteristic... provided in subpart L of this part and 40 CFR 125.30 through 125.32, any existing point source subject to...

40 CFR 440.33 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2014 CFR

2014-07-01

...) The concentration of pollutants discharged in mine drainage from mines, either open-pit or underground, that produce uranium ore, including mines using in-situ leach methods, shall not exceed: Effluent...). Except as provided in subpart L of this part and 40 CFR 125.30 through 125.32, any existing point source...

40 CFR 440.33 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2010 CFR

2010-07-01

... concentration of pollutants discharged in mine drainage from mines, either open-pit or underground, that produce uranium ore, including mines using in-situ leach methods, shall not exceed: Effluent characteristic... provided in subpart L of this part and 40 CFR 125.30 through 125.32, any existing point source subject to...

Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

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

Farmer, J.C.; Van Konynenburg, R.A.; McCright, R.D.

1988-04-01

Three iron- to nickel-based austenitic alloys (Types 304L and 316L stainless steels and Alloy 825) are being considered as candidate materials for the fabrication of high-level radioactive-waste containers. Waste will include fuel assemblies from reactors as well as high-level waste in borosilicate glass forms, and will be sent to the prospective repository at Yucca Mountain, Nevada. The decay of radionuclides in the repository will result in the generation of substantial heat and in fluences of gamma radiation. Container materials may undergo any of several modes of degradation in this environment, including atmospheric oxidation; uniform aqueous phase corrosion; pitting; crevice corrosion;more » sensitization and intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This report is an analysis of data relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of the three austenitic candidate alloys. The candidates are compared in terms of their susceptibilities to these forms of corrosion. Although all three candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these types of localized corrosion (LC); such resistance is important because pits can penetrate the metal and serve as crack initiation sites. Both Types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented in Alloy 825 under comparable conditions. Gamma radiation has been found to enhance SCC in Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while the effects of microbiologically induced corrosion have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. 211 refs., 49 figs., 10 tabs.« less

76 FR 14045 - Notice of Intent To Repatriate Cultural Items: U.S. Department of the Interior, Bureau of Indian...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-15

... State Museum, University of Arizona, Tucson, AZ, that meet the definition of unassociated funerary.... Material culture characteristics of these traditions include a temporal progression from earlier pit houses... of the material culture attributes and a subsistence pattern, which included hunting and gathering...

Particle and gas emissions from a simulated coal-burning household fire pit.

PubMed

Tian, Linwei; Lucas, Donald; Fischer, Susan L; Lee, S C; Hammond, S Katharine; Koshland, Catherine P

2008-04-01

An open fire was assembled with firebricks to simulate the household fire pit used in rural China, and 15 different coals from this area were burned to measure the gaseous and particulate emissions. Particle size distribution was studied with a microorifice uniform-deposit impactor (MOUDI). Over 90% of the particulate mass was attributed to sub-micrometer particles. The carbon balance method was used to calculate the emission factors. Emission factors for four pollutants (particulate matter, CO2, total hydrocarbons, and NOx) were 2-4 times higherfor bituminous coals than for anthracites. In past inventories of carbonaceous emissions used for climate modeling, these two types of coal were not treated separately. The dramatic emission factor difference between the two types of coal warrants attention in the future development of emission inventories.

Gaseous Oxidized Mercury Flux from Substrates Associated with Industrial Scale Gold Mining in Nevada, USA

NASA Astrophysics Data System (ADS)

Miller, M. B.

2015-12-01

Gaseous elemental and oxidized mercury (Hg) fluxes were measured in a laboratory setting from substrate materials derived from industrial-scale open pit gold mining operations in Nevada, USA. Mercury is present in these substrates at a range of concentrations (10 - 40000 ng g-1), predominantly of local geogenic origin in association with the mineralized gold ores, but altered and redistributed to a varying degree by subsequent ore extraction and processing operations, including deposition of Hg recently emitted to the atmosphere from large point sources on the mines. Waste rock, heap leach, and tailings material usually comprise the most extensive and Hg emission relevant substrate surfaces. All three of these material types were collected from active Nevada mine sites in 2010 for previous research, and have since been stored undisturbed at the University of Nevada, Reno. Gaseous elemental Hg (GEM) flux was previously measured from these materials under a variety of conditions, and was re-measured in this study, using Teflon® flux chambers and Tekran® 2537A automated ambient air analyzers. GEM flux from dry undisturbed materials was comparable between the two measurement periods. Gaseous oxidized Hg (GOM) flux from these materials was quantified using an active filter sampling method that consisted of polysulfone cation-exchange membranes deployed in conjunction with the GEM flux apparatus. Initial measurements conducted within greenhouse laboratory space indicate that in dry conditions GOM is deposited to relatively low Hg cap and leach materials, but may be emitted from the much higher Hg concentration tailings material.

On lunar evidence for a possible large increase in solar flare activity approximately 2 x 10 to the 4th years ago

NASA Technical Reports Server (NTRS)

Zook, H. A.

1980-01-01

Data from lunar materials which may be interpreted as suggesting an increase in solar cosmic ray activity approximately 20,000 years ago is examined. The evidence includes the iron track within pit data of Hartung and Storzer (1974), the lunar whole rock pit and track data, lunar C-14 radioactivity data, lunar Ni-59 radioactivity data, the impact pit and iron track data of Morrison and Zinner (1975, 1977) and the lunar thermoluminescence data. While numerous explanations are possible for each set of data, it is shown that the first four data sets may be explained by a past increase in solar cosmic ray activity, and the remaining data sets are not necessarily incompatible with solar activity a factor of 20 to 40 times higher than at present for several thousand years prior to about 20,000 years ago.

Geotechnical approach for occupational safety risk analysis of critical slope in open pit mining as implication for earthquake hazard

NASA Astrophysics Data System (ADS)

Munirwansyah; Irsyam, Masyhur; Munirwan, Reza P.; Yunita, Halida; Zulfan Usrina, M.

2018-05-01

Occupational safety and health (OSH) is a planned effort to prevent accidents and diseases caused by work. In conducting mining activities often occur work accidents caused by unsafe field conditions. In open mine area, there is often a slump due to unstable slopes, which can disrupt the activities and productivity of mining companies. Based on research on stability of open pit slopes conducted by Febrianti [8], the Meureubo coal mine located in Aceh Barat district, on the slope of mine was indicated unsafe slope conditions, it will be continued research on OSH for landslide which is to understand the stability of the excavation slope and the shape of the slope collapse. Plaxis software was used for this research. After analyzing the slope stability and the effect of landslide on OSH with Job Safety Analysis (JSA) method, to identify the hazard to work safety, risk management analysis will be conducted to classified hazard level and its handling technique. This research aim is to know the level of risk of work accident at the company and its prevention effort. The result of risk analysis research is very high-risk value that is > 350 then the activity must be stopped until the risk can be reduced to reach the risk value limit < 20 which is allowed or accepted.

Hot corrosion of ceramic engine materials

NASA Technical Reports Server (NTRS)

Fox, Dennis S.; Jacobson, Nathan S.; Smialek, James L.

1988-01-01

A number of commercially available SiC and Si3N4 materials were exposed to 1000 C in a high velocity, pressurized burner rig as a simulation of a turbine engine environment. Sodium impurities added to the burner flame resulted in molten Na2SO4 deposition, attack of the SiC and Si4N4 and formation of substantial Na2O-x(SiO2) corrosion product. Room temperature strength of the materials decreased. This was a result of the formation of corrosion pits in SiC, and grain boundary dissolution and pitting in Si3N4. Corrosion regimes for such Si-based ceramics have been predicted using thermodynamics and verified in rig tests of SiO2 coupons. Protective mullite coatings are being investigated as a solution to the corrosion problem for SiC and Si3N4. Limited corrosion occurred to cordierite (Mg2Al4Si5O18) but some cracking of the substrate occurred.

High efficiency low cost thin film silicon solar cell design and method for making

DOEpatents

Sopori, B.L.

1999-04-27

A semiconductor device is described having a substrate, a conductive intermediate layer deposited onto said substrate, wherein the intermediate layer serves as a back electrode, an optical reflector, and an interface for impurity gettering, and a semiconductor layer deposited onto said intermediate layer, wherein the semiconductor layer has a grain size at least as large as the layer thickness, and preferably about ten times the layer thickness. The device is formed by depositing a metal layer on a substrate, depositing a semiconductive material on the metal-coated substrate to produce a composite structure, and then optically processing the composite structure by illuminating it with infrared electromagnetic radiation according to a unique time-energy profile that first produces pits in the backside surface of the semiconductor material, then produces a thin, highly reflective, low resistivity alloy layer over the entire area of the interface between the semiconductor material and the metal layer, and finally produces a grain-enhanced semiconductor layer. The time-energy profile includes increasing the energy to a first energy level to initiate pit formation and create the desired pit size and density, then ramping up to a second energy level in which the entire device is heated to produce an interfacial melt, and finally reducing the energy to a third energy level and holding for a period of time to allow enhancement in the grain size of the semiconductor layer. 9 figs.

Landslide stability analysis on basis of LIDAR data extraction

NASA Astrophysics Data System (ADS)

Hu, Hui; Fernandez-Steeger, Tomas M.; Dong, Mei; Azzam, Rafig

2010-05-01

Currently, existing contradictory between remediation and acquisition from natural resource induces a series of divergences. With regard to open pit mining, legal regulation requires human to fill back the open pit area with water or recreate new landscape by other materials; on the other hand, human can not help excavating the mining area due to the shortage of power resource. However, to engineering geologists, one coincident problem which takes place not only in filling but also in mining operation should be paid more attention to, i.e. the slope stability analysis within these areas. There are a number of construction activities during remediation or mining process which can directly or indirectly cause slope failure. Lives can be endangered since local failure either while or after remediation; for mining process, slope failure in a bench, which carries a main haul road or is adjacent to human activity area, would be significant catastrophe to the whole mining program. The stability of an individual bench or slope is controlled by several factors, which are geological condition, morphology, climate, excavation techniques and transportation approach. The task which takes the longest time is to collect the morphological data. Consequently, it is one of the most dangerous tasks due to the time consuming in mining field. LIDAR scanning for morphological data collecting can help to skip this obstacle since advantages of LIDAR techniques as follows: • Dynamic range available on the market: from 3 m to beyond 1 km, • Ruggedly designed for demanding field applications, • Compact, easily hand-carried and deployed by a single operator. In 2009, scanning campaigns for 2 open pit quarry have been carried out. The aim for these LIDAR detections is to construct a detailed 3D quarry model and analyze the bench stability to support the filling planning. The 3D quarry surface was built up by using PolyWorks 10.1 on basis of LIDAR data. LIDAR data refining takes an important role during surface construction for further more precise analysis purpose. 3D geological model can be built based on the connection between surface model and geological data like borehole data in GOCAD. Regarding the bench stability analysis, LEM (Limit Equilibrium Method) analysis using Janbu and FEM (Finite Element Method) have been adopted during this analyzing task. A program was developed to convert GOCAD 2D section data directly into the FEM software. The meshed model is then used for stability analysis. In one quarry, 3 cross sections have been extracted on basis of LIDAR original data (original 3 cross sections). To evaluate the advantages of LIDAR data for slope analysis, the results of safety factor (SF) were compared to simplified slope models as they are used normally. The comparison showed that variations of the SF reach up to 9%. Additionally, conservative evaluation demonstrated by SF results based on simplified model is not adaptive for decision making of filling.

Selectable-Tip Corrosion-Testing Electrochemical Cell

NASA Technical Reports Server (NTRS)

Lomness, Janice; Hintze, Paul

2008-01-01

The figure depicts aspects of an electrochemical cell for pitting- corrosion tests of material specimens. The cell is designed to generate a region of corrosion having a pit diameter determined by the diameter of a selectable tip. The average depth of corrosion is controlled by controlling the total electric charge passing through the cell in a test. The cell is also designed to produce minimal artifacts associated with crevice corrosion. There are three selectable tips, having diameters of 0.1 in. (0.254 cm), 0.3 in. (0.762 cm), and 0.6 in. (1.524 cm), respectively.

Arsia Mons

NASA Technical Reports Server (NTRS)

2002-01-01

(Released 20 May 2002) The Science This THEMIS visible image shows a portion of the summit region of Arsia Mons, one of the four giant volcanoes in the Tharsis region of Mars. This volcano stands over 20 km above the surrounding plains, and is approximately 450 km in diameter at its base. A large volcanic crater known as a 'caldera' is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera alone is over 120 km in diameter, making it larger than many volcanoes on Earth. The THEMIS image shows a portion of the eastern wall of the caldera, revealing the steep walls and linear features associated with the collapse that formed the caldera. The ridge with linear faults that extends from the lower left toward the center right was formed at some stage during a collapse event. Several circular pits are present, and several of these pits appear to have coalesced into a long, unusual trough. These pits and troughs likely formed when lava was removed from beneath them and the overlying surface collapsed. Numerous lava flows can be seen on the floor of the caldera. Many of these flows occurred after the collapse that formed the caldera crater, and have buried many of the pre-existing features. The faulted, pitted ridge appears to have been partially flooded by these lava flows, indicating that the caldera of Arsia Mons has undergone a complex history of numerous events. The wispy bright features throughout the image are water-ice clouds that commonly form over the volcano summits during the early northern spring when this image was acquired. The Story When the Martian volcano Arsia Mons exploded long ago, it sent lava spewing out everywhere. With the removal of this molten material, the volcano then collapsed at its opening (the top of its cone) to form a sunken volcanic crater known as a caldera. You can see it more fully in the context image to the right. The eastern wall of the caldera is the pale white strip running diagonally across the bottom third of the image. By looking at this steep wall and the streaks running down its sides, you can imagine how all of the remaining material rushed down into the void left by expelled magma and ash to form the caldera depression. Numerous lava flows that occurred after the collapse texturize the floor of the caldera, and have buried many of its pre-existing features. These later lava flows might be a little harder to see, because wispy bright features blur this image slightly, giving it an almost marbled, hazy appearance. They are water-ice clouds that typically form over the volcano summits during the early northern spring. What they don't obscure very much is the raised ridge created during the collapse of the volcano's cone (running slightly north of the caldera wall along the same diagonal). Draped across the smoother caldera floor, this pitted ridge has been partially flooded by lava flows, indicating quite a complex history of geologic events has taken place here. Faults cut through the ridge, contributing to its streamer-like appearance. And, in a process somewhat like the formation of the caldera itself, all of the round and oblong pits and troughs in the ridge formed when lava was removed from underneath these areas, and the overlying surface then collapsed. Arsia Mons is one of the four giant Martian volcanoes found in a region called Tharsis. Arsia Mons is about 270 miles wide in diameter at its base, and rises 12 miles high above the surrounding plains. The caldera at its summit is more than 72 miles wide, making it larger than volcanoes on Earth. By comparison, the largest volcano on Earth is Mauna Loa on the island of Hawaii, which is about 6.3 miles high and 75 miles wide in diameter at its base.

Bioremediation of Acidic and Metalliferous Drainage (AMD) through organic carbon amendment by municipal sewage and green waste.

PubMed

McCullough, Clint D; Lund, Mark A

2011-10-01

Pit lakes (abandoned flooded mine pits) represent a potentially valuable water resource in hot arid regions. However, pit lake water is often characterised by low pH with high dissolved metal concentrations resulting from Acidic and Metalliferous Drainage (AMD). Addition of organic matter to pit lakes to enhance microbial sulphate reduction is a potential cost effective remediation strategy. However, cost and availability of suitable organic substrates are often limiting. Nevertheless, large quantities of sewage and green waste (organic garden waste) are often available at mine sites from nearby service towns. We treated AMD pit lake water (pH 2.4) from tropical, North Queensland, Australia, with primary-treated sewage sludge, green waste, and a mixture of sewage and green waste (1:1) in a controlled microcosm experiment (4.5 L). Treatments were assessed at two different rates of organic loading of 16:1 and 32:1 pit water:organic matter by mass. Combined green waste and sewage treatment was the optimal treatment with water pH increased to 5.5 in only 145 days with decreases of dissolved metal concentrations. Results indicated that green waste was a key component in the pH increase and concomitant heavy metal removal. Water quality remediation was primarily due to microbially-mediated sulphate reduction. The net result of this process was removal of sulphate and metal solutes to sediment mainly as monosulfides. During the treatment process NH(3) and H(2)S gases were produced, albeit at below concentrations of concern. Total coliforms were abundant in all green waste-treatments, however, faecal coliforms were absent from all treatments. This study demonstrates addition of low-grade organic materials has promise for bioremediation of acidic waters and warrants further experimental investigation into feasibility at higher scales of application such as pit lakes. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

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

K. B. Campbell

The following site closure activities were performed at the 34 Corrective Action Sites (CASs) comprising Corrective Action Unit (CAU) 417 and are documented in this report: (1) No closure action was taken at 13 CASs (17 sites): 58-05-01,58-07-01,58-05-04, 58-09-05 (Mud Pits C and D only), 58-35-01,58-05-02,58-09-06 (Mud Pits A, B, C, and D), 58-10-06,58-19-01,58-35-02,58-44-04,58-05-04, and 58-09-03 (Mud Pit E only). (2) Housekeeping activities, collecting scrap materials, and transporting to approved landfill sites at the NTS were used to close seven CASs: 58-44-01,58-44-02,58-44-05, 58-98-03,58-98-01,58-98-02, and 58-98-04. (3) Two CASs (58-05-03 and 58-99-01) were closed by excavation and removal of USTs. (4)more » Two septic tanks (CASs 58-05-05 and 58-05-06) were closed by backfilling with clean fill. (5) Site posting with above-grade monuments and attached warning signs and land-use restrictions were used to close seven CASs (nine sites): 58-09-02,58-09-05 (Mud Pit E only), 58-09-06 (Mud Pit E only), 58-10-01,58-25-01,58-09-03 (Mud Pits A, B, and D), and 58-10-05. (6) Clean closure by excavation soil with TPH levels greater than the NDEP action level of 100 mg/kg and limited regrading was used to close five CASs: 58-10-03,58-44-06, 58-44-03,58-10-02, and 58-10-04. (7) Construction of engineered covers was used to close in place two CASs: 58-09-01 and 58-09-03 (Mud Pit C only). Following construction, a fence was constructed around each cover to prevent damage to the cover or intrusion by wildlife.« less

Workflow Enhancement (WE) Improves Safety in Radiation Oncology: Putting the WE and Team Together

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

Chao, Samuel T., E-mail: chaos@ccf.org; Rose Ella Burkhardt Brain Tumor and Neuro-oncology Center, Cleveland Clinic, Cleveland, Ohio; Meier, Tim

Purpose: To review the impact of a workflow enhancement (WE) team in reducing treatment errors that reach patients within radiation oncology. Methods and Materials: It was determined that flaws in our workflow and processes resulted in errors reaching the patient. The process improvement team (PIT) was developed in 2010 to reduce errors and was later modified in 2012 into the current WE team. Workflow issues and solutions were discussed in PIT and WE team meetings. Due to tensions within PIT that resulted in employee dissatisfaction, there was a 6-month hiatus between the end of PIT and initiation of the renamed/redesigned WEmore » team. In addition to the PIT/WE team forms, the department had separate incident forms to document treatment errors reaching the patient. These incident forms are rapidly reviewed and monitored by our departmental and institutional quality and safety groups, reflecting how seriously these forms are treated. The number of these incident forms was compared before and after instituting the WE team. Results: When PIT was disbanded, a number of errors seemed to occur in succession, requiring reinstitution and redesign of this team, rebranded the WE team. Interestingly, the number of incident forms per patient visits did not change when comparing 6 months during the PIT, 6 months during the hiatus, and the first 6 months after instituting the WE team (P=.85). However, 6 to 12 months after instituting the WE team, the number of incident forms per patient visits decreased (P=.028). After the WE team, employee satisfaction and commitment to quality increased as demonstrated by Gallup surveys, suggesting a correlation to the WE team. Conclusions: A team focused on addressing workflow and improving processes can reduce the number of errors reaching the patient. Time is necessary before a reduction in errors reaching patients will be seen.« less

Earth Observations taken by the Expedition 15 Crew

NASA Image and Video Library

2007-09-20

ISS015-E-29867 (20 Sept. 2007) --- Bingham Canyon Mine, Utah is featured in this image photographed by an Expedition 15 crewmember on the International Space Station. The Bingham Canyon Mine (center) located approximately 32 kilometers to the southeast of Salt Lake City, UT is one of the largest open-pit mines in the world, measuring over 4 kilometers wide and 1,200 meters deep. The mine exploits a porphyry copper, a type of geological structure formed by crystal-rich magma moving upwards through pre-existing rock layers. As the magma cools and crystallizes (forming an igneous rock with large crystals in a fine-grained matrix, known as a porphyry), hot fluids circulate through the magma and surrounding rocks via fractures. This process of hydrothermal alteration typically forms copper-bearing and other minerals in spatial patterns that a geologist recognizes as a potential porphyry copper deposit. Parallel benches (stepped terraces), visible along the western pit face (center left), range from 16 to 25 meters high - these provide access for equipment to work the rock face, as well as maintaining stability of the sloping pit walls. A dark, larger roadway is also visible directly below the benches. Brown to gray, flat topped hills of gangue (waste rock) surround the pit, and are thrown into sharp relief by shadows and the oblique viewing angle of this image. Leachate reservoirs associated with ore processing are visible to the south of the city of Bingham Canyon, UT (right).

ASSOCIATION BETWEEN NON-ENZYMATIC GLYCATION, RESORPTION, AND MICRODAMAGE IN HUMAN TIBIAL CORTICES

PubMed Central

Karim, Lamya; Diab, Tamim; Vashishth, Deepak

2015-01-01

Purpose/Introduction Changes in the quality of bone material contribute significantly to bone fragility. In order to establish a better understanding of the interaction of the different components of bone quality and their influence on bone fragility we investigated the relationship between non-enzymatic glycation, resorption, and microdamage generated in vivo in cortical bone using bone specimens from the same donors. Methods Total fluorescent advanced glycation end-products (AGEs) were measured in 96 human cortical bone samples from 83 donors. Resorption pit density, average resorption pit area, and percent resorption area were quantified in samples from 48 common donors with AGE measurements. Linear microcrack density and diffuse damage were measured in 21 common donors with AGE and resorption measurements. Correlation analyses were performed between all measured variables to establish the relationships among them and their variation with age. Results We found that average resorption pit area and percent resorption area decreased with increasing AGEs independently of age. Resorption pit density and percent resorption area demonstrated negative age-adjusted correlation with diffuse damage. Furthermore, average resorption pit area, resorption pit density, and percent resorption area were found to decrease significantly with age. Conclusions The current study demonstrated the in vivo interrelationship between the organic constituents, remodeling, and damage formation in cortical bone. In addition to the age-related reduction in resorption, there is a negative correlation between AGEs and resorption independent of age. This inverse relationship indicates that AGEs alter the resorption process and/or accumulate in the tissue as a result of reduced resorption and may lead to bone fragility by adversely affecting fracture resistance through altered bone matrix properties. PMID:25326375

30 CFR 56.3131 - Pit or quarry wall perimeter.

Code of Federal Regulations, 2011 CFR

2011-07-01

... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Ground Control... performing their assigned tasks, loose or unconsolidated material shall be sloped to the angle of repose or...

30 CFR 56.3131 - Pit or quarry wall perimeter.

Code of Federal Regulations, 2010 CFR

2010-07-01

... NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Ground Control... performing their assigned tasks, loose or unconsolidated material shall be sloped to the angle of repose or...

7 CFR 51.1212 - U.S. No. 1.

Code of Federal Regulations, 2012 CFR

2012-01-01

... which are mature but not soft or overripe, well formed, and which are free from decay, growth cracks... foreign material, bacterial spot, scab, scale, hail injury, leaf or limb rubs, split pits, other disease...

7 CFR 51.1212 - U.S. No. 1.

Code of Federal Regulations, 2010 CFR

2010-01-01

... which are mature but not soft or overripe, well formed, and which are free from decay, growth cracks... foreign material, bacterial spot, scab, scale, hail injury, leaf or limb rubs, split pits, other disease...

7 CFR 51.1212 - U.S. No. 1.

Code of Federal Regulations, 2011 CFR

2011-01-01

... which are mature but not soft or overripe, well formed, and which are free from decay, growth cracks... foreign material, bacterial spot, scab, scale, hail injury, leaf or limb rubs, split pits, other disease...

Land disturbances from strip-mining in eastern Kentucky: 2. Princess Coal Reserve District

Treesearch

William T. Plass

1967-01-01

Open-pit or strip-mining - primarily for coal - has expanded rapidly in eastern Kentucky during the past 15 years. Information about the amount, location, and general characteristics of the disturbed areas is necessary for appraising the economic impacts and overall effects of strip-mining in that section of the state, for planning reclamation programs, and for...

Land disturbances from strip-mining in eastern Kentucky: 1. Upper Cumberland coal reserve district

Treesearch

William T. Plass

1966-01-01

Open-pit or strip-mining - primarily for coal - has expanded rapidly in eastern Kentucky during the past 15 years. Information about the amount, location, and general characteristics of the disturbed areas is necessary for appraising the economic impacts and overall effects of strip-mining in that section of the state, for planning reclamation programs, and for...

78 FR 77706 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Gemfield Mine...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-24

... gold mine and associated processing and ancillary facilities. The project would be located on public... media, newspapers and the BLM Web site at: http://www.blm.gov/nv/st/en/fo/battle_mountain_field.html... to construct, operate, reclaim, and close an open pit, heap leach, gold mining operation known as the...

Multiculturalism as State Policy. Conference Report. Second Canadian Conference on Multiculturalism, Government Conference Centre (Ottawa, Ontario, February 13-15, 1976).

ERIC Educational Resources Information Center

Canadian Consultative Council on Multiculturalism, Ottawa (Ontario).

The Second Canadian Conference on Multiculturalism was held to clarify some of the issues upon which multiculturalism as a concept and as a policy depend. Cultural pluralism was investigated within the social, political, and historical framework of Canadian society. The opening session, called "The Bear Pit," invited questions and…

A deposit model for magmatic iron-titanium-oxide deposits related to Proterozoic massif anorthosite plutonic suites: Chapter K in Mineral Deposit Models for Resource Assessment

USGS Publications Warehouse

Woodruff, Laurel G.; Nicholson, Suzanne W.; Fey, David L.

2013-01-01

Active mines have developed large open pits with extensive waste-rock piles, but because of the nature of the ore and waste rock, the major environmental impacts documented at the mine sites are reported to be waste disposal issues and somewhat degraded water quality.

SEASONAL VARIATIONS OF DISSOLVED MERCURY CONCENTRATIONS AT THE SULPHUR BANK MERCURY MINE, CLEAR LAKE, CALIFORNIA: IMPLICATIONS FOR MINE DRAINAGE MONITORING

EPA Science Inventory

The Sulphur Bank Mercury Mine in Lake County, California (SBMM) was operated from the 1860s through the 1950s. Mining for sulfur started with surface operations and then progressed to shaft and later open pit techniques to obtain mercury. SBMM is located adjacent to the shore o...

40 CFR 440.32 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2010 CFR

2010-07-01

..., radium and vanadium including mill-mine facilities and mines using in-situ leach methods shall not exceed...). Except as provided in subpart L of this part and 40 CFR 125.30 through 125.32, any existing point source... available (BPT): (a) The concentration of pollutants discharged in mine drainage from mines, either open-pit...

40 CFR 440.32 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., radium and vanadium including mill-mine facilities and mines using in-situ leach methods shall not exceed...). Except as provided in subpart L of this part and 40 CFR 125.30 through 125.32, any existing point source... available (BPT): (a) The concentration of pollutants discharged in mine drainage from mines, either open-pit...

Intelligent Mining Engineering Systems in the Structure of Industry 4.0

NASA Astrophysics Data System (ADS)

Rylnikova, Marina; Radchenko, Dmitriy; Klebanov, Dmitriy

2017-11-01

The solution of the problem of improving the human environment and working conditions at mines is based on the provision of the rationale of parameters and conditions for the implementation of an environmentally balanced cycle of comprehensive development of mineral deposits on the basis of the design of mining engineering systems characterized by the minimization of the human factor effect in danger zones of mining operations. In this area, robotized technologies are being developed, machinery and mechanisms with the elements of artificial intelligence, and mining and transport system automatic controls are being put into service throughout the world. In the upcoming decades, mining machines and mechanisms will be virtually industrial robots. The article presents the results of zoning of open-pit and underground mine production areas, as well as mining engineering system of combined development depending on the fact and periodicity of human presence in zones of mining processes. As a surface geotechnology case study, the software structure based on a modular concept is described. The performance philosophy of mining and transport equipment with the elements of artificial intelligence is shown when it is put into service in an open pit.

Using radon-222 for tracing groundwater discharge into an open-pit lignite mining lake--a case study.

PubMed

Schmidt, Axel; Schubert, Michael

2007-12-01

Groundwater discharge into an open pit lignite mining lake was investigated using radon-222 as a naturally occurring environmental tracer. The chosen study site was a meromictic lake, i.e., a water body that is divided horizontally into two separate layers--the upper mixolimnion (with seasonal mixing) and the lower monimolimnion (without seasonal mixing). For the estimation of groundwater discharge rates into the lake, a simple box model including all radon sinks and sources related to each layer was applied. Two field investigations were performed. During the October campaign, the total groundwater discharge into the lake was found to be 18.9 and 0.7 m(3) d(-1) for the mixolimnion and monimolimnion, respectively. During the December campaign, the groundwater discharge into the mixolimnion was 15.0 m(3) d(-1), whereas no discharge at all was observed into the monimolimnion. Based on the given water volumes, the residence time of lake water was 5.3 years for the monimolimnion and varies between 0.9 and 1.1 years for the mixolimnion. The investigation confirmed radon to be a useful environmental tracer for groundwater and surface water interactions in meromictic lake environments.

A simplified economic filter for open-pit mining and heap-leach recovery of copper in the United States

USGS Publications Warehouse

Long, Keith R.; Singer, Donald A.

2001-01-01

Determining the economic viability of mineral deposits of various sizes and grades is a critical task in all phases of mineral supply, from land-use management to mine development. This study evaluates two simple tools for estimating the economic viability of porphyry copper deposits mined by open-pit, heap-leach methods when only limited information on these deposits is available. These two methods are useful for evaluating deposits that either (1) are undiscovered deposits predicted by a mineral resource assessment, or (2) have been discovered but for which little data has been collected or released. The first tool uses ordinary least-squared regression analysis of cost and operating data from selected deposits to estimate a predictive relationship between mining rate, itself estimated from deposit size, and capital and operating costs. The second method uses cost models developed by the U.S. Bureau of Mines (Camm, 1991) updated using appropriate cost indices. We find that the cost model method works best for estimating capital costs and the empirical model works best for estimating operating costs for mines to be developed in the United States.

Proteomics technique opens new frontiers in mobilome research.

PubMed

Davidson, Andrew D; Matthews, David A; Maringer, Kevin

2017-01-01

A large proportion of the genome of most eukaryotic organisms consists of highly repetitive mobile genetic elements. The sum of these elements is called the "mobilome," which in eukaryotes is made up mostly of transposons. Transposable elements contribute to disease, evolution, and normal physiology by mediating genetic rearrangement, and through the "domestication" of transposon proteins for cellular functions. Although 'omics studies of mobilome genomes and transcriptomes are common, technical challenges have hampered high-throughput global proteomics analyses of transposons. In a recent paper, we overcame these technical hurdles using a technique called "proteomics informed by transcriptomics" (PIT), and thus published the first unbiased global mobilome-derived proteome for any organism (using cell lines derived from the mosquito Aedes aegypti ). In this commentary, we describe our methods in more detail, and summarise our major findings. We also use new genome sequencing data to show that, in many cases, the specific genomic element expressing a given protein can be identified using PIT. This proteomic technique therefore represents an important technological advance that will open new avenues of research into the role that proteins derived from transposons and other repetitive and sequence diverse genetic elements, such as endogenous retroviruses, play in health and disease.

Can vector control play a useful supplementary role against bancroftian filariasis?

PubMed Central

Maxwell, C. A.; Mohammed, K.; Kisumku, U.; Curtis, C. F.

1999-01-01

A single campaign of mass treatment for bancroftian filariasis with diethylcarbamazine (DEC) in Makunduchi, a town in Zanzibar, United Republic of Tanzania, combined with elimination of mosquito breeding in pit latrines with polystyrene beads was followed by a progressive decline over a 5-year period in the microfilarial rate from 49% to 3%. Evidence that vector control had contributed to this long-term decline was obtained by comparison with another town, Moga, where a DEC campaign was used without vector control and where resurgence of microfilariae could be observed 3-6 years after the campaign. In Zanzibar town, treatment of 3844 wet pit latrines and cesspits with polystyrene beads reduced the adult mosquito population in houses by about 65%. Supplementary treatment of open drains and marshes with Bacillus sphaericus produced little or no additional reduction compared to a sector of the town where only pit treatment with polystyrene was carried out. The cost and effort of achieving the 65% reduction in mosquito population could hardly be justified for its impact on filariasis alone, but its noticeable impact on biting nuisance might help to gain community support for an integrated programme. PMID:10083712

Mercury's Crater-Hosted Hollows: Chalcogenide Pryo-Thermokarst, and Permafrost Analogs on Earth, Mars, and Titan

NASA Astrophysics Data System (ADS)

Kargel, Jeffrey

2013-04-01

MESSENGER has acquired stunning images of pitted, light-toned and variegated light/dark terrains located primarily on the floors—probably impact-melt sheets—of many of Mercury's large craters. Termed "hollows", the pitted terrains are geomorphologically similar to some on Mars formed by sublimation of ice-rich permafrost and to lowland thermokarst on Earth formed by permafrost thaw; to "swiss cheese" terrain forming by sublimation of frozen CO2 at the Martian South Pole; and to suspected hydrocarbon thermokarst at Titan's poles. I shall briefly review some analogs on these other worlds. The most plausible explanation for Mercury's hollows is terrain degradation involving melting or sublimation of heterogeneous chalcogenide and sulfosalt mineral assemblages. I refer to these Mercurian features as pyrothermokarst; the etymological redundancy distinguishes the conditions and mineral agents from the ice-related features on Earth and Mars, though some of the physical processes may be similar. Whereas ice and sulfur have long been suspected and ice recently was discovered in permanently shadowed craters of Mercury's polar regions, the hollows occur down to the equator, where neither ice nor sulfur is plausible. The responsible volatiles must be only slightly volatile on the surface and/or in the upper crust of Mercury's low to middle latitudes at 400-800 K, but they must be capable of either melting or sublimating on geologically long time scales. Under prevailing upper crustal and surface temperatures, chalcophile-rich "permafrost" can undergo either desulfidation or melting reactions that could cause migration or volume changes of the permafrost, and hence lead to collapse and pitting. I propose the initial emplacement of crater-hosted chalcogenides, sulfosalts and related chalcophile materials such as pnictides, in impact-melt pools (involving solid-liquid and silicate-sulfide fractionation) and further differentiation by associated dry or humid fumaroles (solid-vapor and liquid-vapor fractionation and recondensation). Key phase transitions can occur in the temperature range of Mercury's surface and upper crust. Vapor-solid, vapor-liquid, and solid-liquid transitions of the heated materials resulted in migration and loss of volatiles and anatectic liquids, causing collapse pits to form. Seasonal heating near perihelion may work together with geothermal flux or early impact heating to drive off volatiles and produce the pits. In some cases, local recondensation of moderately volatile materials may have occurred on the rims of the pits; some volatiles may have been transported to the polar regions or lost by exospheric escape. Impacts by comets may have caused local oxidation and formation of oxygenated salts and other minerals, whose local recondensation from fumarole gases can explain the light-toned layers and light-toned rims of many pits. Plating of native volatile metals and semi-metals may also account for some light-toned deposits. Large contrasts in thermal conductivity as well as local topographic shading and latitude controls may result in large differences in element mobility and mineral assemblages. Pyrothermokarst on Mercury may be more chemically heterogeneous and complex in its development than any other thermokarst in the Solar System. Validation of this model would require a future mission with high-resolution multispectral imaging and neutral/ion detection.

Water budgets of Italian and Dutch gravel pit lakes: a study using a fen as a natural evaporation pan, stable isotopes and conservative tracer modeling.

NASA Astrophysics Data System (ADS)

Nella Mollema, Pauline; Antonellini, Marco

2015-04-01

Gravel pits are excavated in aquifers to fulfill the need for construction materials. Flow-through lakes form where the gravel pits are below the water table and fill with groundwater. Their presence changes the drainage patterns, water- and hydrochemical budgets of a watershed. We have studied the water budget of two gravel pit lakes systems using stable H and O isotopes of water as well as conservative tracer (Cl) modeling. The Dutch gravel pit lakes are a fluvial fresh water system of 70 lakes along the Meuse River and the Italian gravel pit lakes are a brackish system along the Adriatic coast. Surface water evaporation from the gravel pit lakes is larger than the actual evapotranspiration of the grass land and forests that were replaced. The ratio of evaporation to total flow into the Dutch lakes was determined by using a Fen as a natural evaporation pan: the isotope content of the Tuspeel Fen, filled with rain water and sampled in a dry and warm summer period (August 2012), is representative for the limiting isotopic enrichment under local hydro meteorological conditions. The Local Evaporation line (LEL) was determined δ2 H = 4.20 δ 18O - 14.10 (R² = 0.99) and the ratio of total inflow to evaporation for three gravel pit lakes were calculated to be 22.6 for the De Lange Vlieter lake used for drinking water production, 11.3 for the Boschmolen Lake and 8.9 for the Anna's Beemd lake showing that groundwater flow is much larger than evaporation. The Italian gravel pit lakes are characterized by high salinity (TDS = 4.6-12.3 g L-1). Stable isotope data show that these latter gravel pit lakes are fed by groundwater, which is a mix between fresh Apennine River water and brackish (Holocene) Adriatic Sea water. The local evaporation line is determined: δ2H = 5.02 δ18O - 10.49. The ratio of total inflow to evaporation is 5. Conservative tracer modeling indicates that the chloride concentration in the Italian gravel pit lakes stabilizes after a short period of rapid increase, because water leaving the lake via groundwater flow, driven by the drainage system, removes part of the Cl that accumulates in the lake due to evapo-concentration. Under climate change, rising sea levels and continuing land subsidence as well as increasing precipitation would increase the need for drainage which would enhance groundwater flow through the lake. The resulting steady-state Cl concentration of the lakes could become less than the current Cl concentration. This effect would be larger than increasing evapo- concentration. Both gravel pit lake systems have a large flux of groundwater into and out of the lakes driven by evaporation and (artificial) drainage with important consequences for the water- and hydrochemical budgets of the whole watershed and in particular on freshwater quantity and groundwater salinity.

Groundwater and surface water interaction in flow-through gravel pit lakes.

NASA Astrophysics Data System (ADS)

Nella Mollema, Pauline; Antonellini, Marco

2015-04-01

Gravel pits are excavated in aquifers to fulfill the need for construction materials. Flow-through lakes form when the gravel pits are below the water table and fill with groundwater. In certain areas there are more than 60 of these lakes close together and their presence changes the drainage patterns and water- and hydrochemical budgets of a watershed. In flow-through gravel pit lakes, groundwater mixes with surface water and interacts with the atmosphere; outflow occurs only via groundwater. The lifespan of gravel pit lakes may be up to thousands of years as their depth to surface ratio is typically large and sedimentation rates are low. We have studied two gravel pit lake systems, a fluvial freshwater system in the Netherlands and a coastal brackish lake system in Italy. One Dutch gravel pit lake studied in detail is in part artificially replenished with Meuse River water for drinking water production that occurs downstream of the lake by water pumps. The Italian gravel pit lakes are fed by brackish groundwater that is a mix of freshwater from precipitation, Apennine Rivers and brackish (Holocene) Adriatic Sea water. Here, the drainage system of the low lying land enhances groundwater flow into the lake. Surface water evaporation is larger in temperate and Mediterranean climates than the actual evapotranspiration of pre-existing grassland and forests. The lakes, therefore, cause a loss of freshwater. The creation of water surfaces allows algae and other flora and fauna to develop. In general, water becomes gradually enriched in certain chemical constituents on its way through the hydrological cycle, especially as groundwater due to water-rock interactions. When groundwater ex-filtrates into gravel pit lakes, the natural flow of solutes towards the sea is interrupted. Hydrochemical analysis of ground- and surface waters, as well as chemical analysis of lake bottom sediments and stable H and O isotope data, show that gravel pit lake water is characterized (among others) by a higher pH, O2 and alkalinity and lower dissolved metal and certain trace concentrations than natural lakes and groundwater. In both settings, groundwater rich in dissolved elements (e.g. Al, As, Fe, Mn, Ni and PO43) flows into the gravel pit lakes where the pH and DO are high, which enhances the (co)precipitation of Fe, Mn and Al oxides that include trace elements. Metal concentrations in the Dutch lake's bottom sediments have increased over a 10 year period. Redox reactions caused by water table lowering and farmland fertilization upstream from the lake explain the metals mobilization and subsequent transport with groundwater towards the lakes. The gravel pit lakes, especially if there are many close together, influence so the cycle of water metals, nutrients as well as other trace elements of a watershed by incorporating them into biomass and bottom sediments or creating an environment where they can remain in concentrated solution.

Geospatial analysis of residential proximity to open-pit coal mining areas in relation to micronuclei frequency, particulate matter concentration, and elemental enrichment factors.

PubMed

Espitia-Pérez, Lyda; Arteaga-Pertuz, Marcia; Soto, José Salvador; Espitia-Pérez, Pedro; Salcedo-Arteaga, Shirley; Pastor-Sierra, Karina; Galeano-Páez, Claudia; Brango, Hugo; da Silva, Juliana; Henriques, João A P

2018-09-01

During coal surface mining, several activities such as drilling, blasting, loading, and transport produce large quantities of particulate matter (PM) that is directly emitted into the atmosphere. Occupational exposure to this PM has been associated with an increase of DNA damage, but there is a scarcity of data examining the impact of these industrial operations in cytogenetic endpoints frequency and cancer risk of potentially exposed surrounding populations. In this study, we used a Geographic Information Systems (GIS) approach and Inverse Distance Weighting (IDW) methods to perform a spatial and statistical analysis to explore whether exposure to PM 2.5 and PM 10 pollution, and additional factors, including the enrichment of the PM with inorganic elements, contribute to cytogenetic damage in residents living in proximity to an open-pit coal mining area. Results showed a spatial relationship between exposure to elevated concentrations of PM 2.5, PM 10 and micronuclei frequency in binucleated (MNBN) and mononucleated (MNMONO) cells. Active pits, disposal, and storage areas could be identified as the possible emission sources of combustion elements. Mining activities were also correlated with increased concentrations of highly enriched elements like S, Cu and Cr in the atmosphere, corroborating its role in the inorganic elements pollution around coal mines. Elements enriched in the PM 2.5 fraction contributed to increasing of MNBN but seems to be more related to increased MNMONO frequencies and DNA damage accumulated in vivo. The combined use of GIS and IDW methods could represent an important tool for monitoring potential cancer risk associated to dynamically distributed variables like the PM. Copyright © 2018 Elsevier Ltd. All rights reserved.

Monitoring of ground movement in open pit iron mines of Carajás Province (Amazon region) based on A-DInSAR techniques using TerraSAR-X data

NASA Astrophysics Data System (ADS)

Silva, Guilherme Gregório; Mura, José Claudio; Paradella, Waldir Renato; Gama, Fabio Furlan; Temporim, Filipe Altoé

2017-04-01

Persistent scatterer interferometry (PSI) analysis of a large area is always a challenging task regarding the removal of the atmospheric phase component. This work presents an investigation of ground movement measurements based on a combination of differential SAR interferometry time-series (DTS) and PSI techniques, applied on a large area of extent with open pit iron mines located in Carajás (Brazilian Amazon Region), aiming at detecting linear and nonlinear ground movement. These mines have presented a history of instability, and surface monitoring measurements over sectors of the mines (pit walls) have been carried out based on ground-based radar and total station (prisms). Using a priori information regarding the topographic phase error and a phase displacement model derived from DTS, temporal phase unwrapping in the PSI processing and the removal of the atmospheric phases can be performed more efficiently. A set of 33 TerraSAR-X (TSX-1) images, acquired during the period from March 2012 to April 2013, was used to perform this investigation. The DTS analysis was carried out on a stack of multilook unwrapped interferograms using an extension of SVD to obtain the least-square solution. The height errors and deformation rates provided by the DTS approach were subtracted from the stack of interferograms to perform the PSI analysis. This procedure improved the capability of the PSI analysis for detecting high rates of deformation, as well as increased the numbers of point density of the final results. The proposed methodology showed good results for monitoring surface displacement in a large mining area, which is located in a rain forest environment, providing very useful information about the ground movement for planning and risk control.

Monitoring of surface movement in a large area of the open pit iron mines (Carajás, Brazil) based on A-DInSAR techniques using TerraSAR-X data

NASA Astrophysics Data System (ADS)

Mura, José C.; Paradella, Waldir R.; Gama, Fabio F.; Silva, Guilherme G.

2016-10-01

PSI (Persistent Scatterer Interferometry) analysis of large area is always a challenging task regarding the removal of the atmospheric phase component. This work presents an investigation of ground deformation measurements based on a combination of DInSAR Time-Series (DTS) and PSI techniques, applied in a large area of open pit iron mines located in Carajás (Brazilian Amazon Region), aiming at detect high rates of linear and nonlinear ground deformation. These mines have presented a historical of instability and surface monitoring measurements over sectors of the mines (pit walls) have been carried out based on ground based radar and total station (prisms). By using a priori information regarding the topographic phase error and phase displacement model derived from DTS, temporal phase unwrapping in the PSI processing and the removal of the atmospheric phases can be performed more efficiently. A set of 33 TerraSAR-X-1 images, acquired during the period from March 2012 to April 2013, was used to perform this investigation. The DTS analysis was carried out on a stack of multi-look unwrapped interferogram using an extension of SVD to obtain the Least-Square solution. The height errors and deformation rates provided by the DTS approach were subtracted from the stack of interferogram to perform the PSI analysis. This procedure improved the capability of the PSI analysis to detect high rates of deformation as well as increased the numbers of point density of the final results. The proposed methodology showed good results for monitoring surface displacement in a large mining area, which is located in a rain forest environment, providing very useful information about the ground movement for planning and risks control.

Streamlined Approach for Environmental Restoration (SAFER) Plan for Corrective Action Unit 544: Cellars, Mud Pits, and Oil Spills, Nevada Test Site, Nevada, Revision 0

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

Mark Krauss

2010-07-01

This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the actions needed to achieve closure for Corrective Action Unit (CAU) 544, Cellars, Mud Pits, and Oil Spills, identified in the Federal Facility Agreement and Consent Order (FFACO). Corrective Action Unit 544 comprises the following 20 corrective action sites (CASs) located in Areas 2, 7, 9, 10, 12, 19, and 20 of the Nevada Test Site (NTS): • 02-37-08, Cellar & Mud Pit • 02-37-09, Cellar & Mud Pit • 07-09-01, Mud Pit • 09-09-46, U-9itsx20 PS #1A Mud Pit • 10-09-01, Mud Pit • 12-09-03, Mud Pit • 19-09-01, Mudmore » Pits (2) • 19-09-03, Mud Pit • 19-09-04, Mud Pit • 19-25-01, Oil Spill • 19-99-06, Waste Spill • 20-09-01, Mud Pits (2) • 20-09-02, Mud Pit • 20-09-03, Mud Pit • 20-09-04, Mud Pits (2) • 20-09-06, Mud Pit • 20-09-07, Mud Pit • 20-09-10, Mud Pit • 20-25-04, Oil Spills • 20-25-05, Oil Spills This plan provides the methodology for field activities needed to gather the necessary information for closing each CAS. There is sufficient information and process knowledge from historical documentation and investigations of similar sites regarding the expected nature and extent of potential contaminants to recommend closure of CAU 544 using the SAFER process. Using the approach approved for previous mud pit investigations (CAUs 530–535), 14 mud pits have been identified that • are either a single mud pit or a system of mud pits, • are not located in a radiologically posted area, and • have no evident biasing factors based on visual inspections. These 14 mud pits are recommended for no further action (NFA), and further field investigations will not be conducted. For the sites that do not meet the previously approved closure criteria, additional information will be obtained by conducting a field investigation before selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible recommendation for closure of the remaining CASs in CAU 544. This will be presented in a closure report (CR) that will be prepared and submitted to the Nevada Division of Environmental Protection (NDEP) for review and approval. The sites will be investigated based on the data quality objectives (DQOs) developed on April 27, 2010, by representatives of NDEP and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office (NNSA/NSO). The DQO process was used to identify and define the type, amount, and quality of data needed to determine and implement appropriate corrective actions for each CAS in CAU 544. The DQO process developed for this CAU identified the following expected closure options: (1) investigation and confirmation that no contamination exists above the final action levels (FALs) leading to an NFA declaration, (2) characterization of the nature and extent of contamination leading to closure in place with use restrictions, (3) clean closure by remediation and verification, (4) closure in place with use restrictions with no investigation if CASs are in crater areas that have been determined to be unsafe to enter, or (5) NFA if the mud pit CAS meets the criteria established during the CAUs 530–535 SAFER investigation. The following summarizes the SAFER activities that will support the closure of CAU 544: • Perform visual inspection of all CASs. • Perform site preparation activities (e.g., utilities clearances, construction of temporary site exclusion zones). • Removal of easily managed, nonhazardous, and nonradioactive debris, including vegetation (e.g., tumbleweeds), at various CASs that interfere with sampling, if required to inspect soil surface or collect soil sample. • Collect environmental samples from designated target populations (e.g., mud pits, cellars, stained soil) to confirm or disprove the presence of contaminants of concern (COCs) as necessary to supplement existing information. • If no COCs are present at a CAS, establish NFA as the corrective action. • If COCs exist, collect environmental samples from designated target populations (e.g., clean soil adjacent to contaminated soil) and submit for laboratory analyses to define the extent of COC contamination. • If a COC is present at a CAS, either - Establish clean closure as the corrective action. The material to be remediated will be removed, disposed of as waste, and verification samples will be collected from remaining soil, or - Establish closure in place as the corrective action and implement the appropriate use restrictions. • Confirm the preferred closure option is sufficient to protect human health and the environment.« less

Investigating Mars: Rabe Crater

NASA Image and Video Library

2017-12-11

Rabe Crater is 108 km (67 miles) across. Craters of similar size often have flat floors. Rabe Crater has some areas of flat floor, but also has a large complex pit occupying a substantial part of the floor. The interior fill of the crater is thought to be layered sediments created by wind and or water action. The pit is eroded into this material. The eroded materials appear to have stayed within the crater forming a large sand sheet with surface dune forms as well as individual dunes where the crater floor is visible. The dunes also appear to be moving from the upper floor level into the pit. In this VIS image the rim of the pit is visible near the top of the image. The Odyssey spacecraft has spent over 15 years in orbit around Mars, circling the planet more than 69000 times. It holds the record for longest working spacecraft at Mars. THEMIS, the IR/VIS camera system, has collected data for the entire mission and provides images covering all seasons and lighting conditions. Over the years many features of interest have received repeated imaging, building up a suite of images covering the entire feature. From the deepest chasma to the tallest volcano, individual dunes inside craters and dune fields that encircle the north pole, channels carved by water and lava, and a variety of other feature, THEMIS has imaged them all. For the next several months the image of the day will focus on the Tharsis volcanoes, the various chasmata of Valles Marineris, and the major dunes fields. We hope you enjoy these images! Orbit Number: 17074 Latitude: -43.6954 Longitude: 34.66 Instrument: VIS Captured: 2005-10-20 04:05 https://photojournal.jpl.nasa.gov/catalog/PIA22139

Defect-Enabled Electrical Current Leakage in Ultraviolet Light-Emitting Diodes

DOE PAGES

Moseley, Michael William; Allerman, Andrew A.; Crawford, Mary H.; ...

2015-04-13

The AlGaN materials system offers a tunable, ultra-wide bandgap that is exceptionally useful for high-power electronics and deep ultraviolet optoelectronics. Moseley et al. (pp. 723–726) investigate a structural defect known as an open-core threading dislocation or ''nanopipe'' that is particularly detrimental to devices that employ these materials. Furthermore, an AlGaN thin film was synthesized using metal-organic chemical-vapor deposition. Electrical current leakage is detected at a discrete point using a conductive atomic-force microscope (CAFM). However, no physical feature or abnormality at this location was visible by an optical microscope. The AlGaN thin film was then etched in hot phosphoric acid, andmore » the same location that was previously analyzed was revisited with the CAFM. The point that previously exhibited electrical current leakage had been decorated with a 1.1 μm wide hexagonal pit, which identified the site of electrical current leakage as a nanopipe and allows these defects to be easily observed by optical microscopy. Moreover, with this nanopipe identification and quantification strategy, the authors were able to correlate decreasing ultraviolet light-emitting diode optical output power with increasing nanopipe density.« less

Examination of Libby, Montana, Fill Material for Background Levels of Amphibole from the Rainy Creek Complex Using Scanning Electron Microscopy and X-Ray Microanalysis

USGS Publications Warehouse

Adams, David T.; Langer, William H.; Hoefen, Todd M.; Van Gosen, Bradley S.; Meeker, Gregory P.

2010-01-01

Natural background levels of Libby-type amphibole in the sediment of the Libby valley in Montana have not, up to this point, been determined. The purpose of this report is to provide the preliminary findings of a study designed by both the U.S. Geological Survey and the U.S. Environmental Protection Agency and performed by the U.S. Geological Survey. The study worked to constrain the natural background levels of fibrous amphiboles potentially derived from the nearby Rainy Creek Complex. The material selected for this study was sampled from three localities, two of which are active open-pit sand and gravel mines. Seventy samples were collected in total and examined using a scanning electron microscope equipped with an energy dispersive x-ray spectrometer. All samples contained varying amounts of feldspars, ilmenite, magnetite, quartz, clay minerals, pyroxene minerals, and non-fibrous amphiboles such as tremolite, actinolite, and magnesiohornblende. Of the 70 samples collected, only three had detectable levels of fibrous amphiboles compatible with those found in the rainy creek complex. The maximum concentration, identified here, of the amphiboles potentially from the Rainy Creek Complex is 0.083 percent by weight.

An in-depth study of Marcia Crater, Vesta

NASA Astrophysics Data System (ADS)

Hiesinger, Harald; Ruesch, Ottaviano; Williams, David A.; Nathues, Andreas; Prettyman, Thomas H.; Tosi, Frederico; De Sanctis, M. Christina; Scully, Jennifer E. C.; Schenk, Paul M.; Aileen Yingst, R.; Denevi, Bret W.; Jaumann, Ralf; Raymond, Carol A.; Russell, Chris T.

2014-05-01

After visiting the second most massive asteroid Vesta from July 2011 to September 2012, the Dawn spacecraft is now on its way to asteroid Ceres. Dawn observed Vesta with three instruments: the German Framing Camera (FC), the Italian Visible and InfraRed mapping spectrometer (VIR), and the American Gamma Ray and Neutron Detector (GRaND) [1]. Marcia crater (190°E, 10°N; 68 x 58 km) is the largest of three adjacent impact structures: Marcia (youngest), Calpurnia, and Minucia (oldest). It is the largest well-preserved post-Rheasilvia impact crater, shows a complex geology [2], is young [2], exhibits evidence for gully-like mass wasting [3], contains the largest location of pitted terrain [4], has smooth impact melt ponds [5], shows enhanced spectral pyroxene signatures on its inner walls [2], and has low abundances of OH and H in comparison to the surrounding low-albedo terrain [6, 7]. Geophysically, the broad region of Marcia and Calpurnia craters is characterized by a higher Bouguer gravity, indicating denser material [9]. Williams et al. [2] have produced a detailed geologic map of Marcia crater and the surrounding terrain. They identified several units within Marcia crater, including bright crater material, pitted terrain, and smooth material. Units outside Marcia, include undivided crater ejecta material, bright lobate material, dark lobate material, and dark crater ray material [2]. Because of its extensive ejecta and fresh appearance, the Marcia impact defines a major stratigraphic event, postdating the Rheasilvia impact [2]. However, the exact age of Marcia crater is still under debate. Compositionally, Marcia crater is characterized by higher iron abundances, which were interpreted as more basaltic-eucrite-rich materials suggesting that this region has not been blanketed by diogenitic materials from large impact events [10, 11]. Using FC data, [13] identified "gray material" associated with the ejecta blanket of Marcia crater. This material is characterized by a 0.75-mm reflectance of ~15%, a shallow visible slope, and a weak R(0.75 µm)/R(0.92 µm) ratio [12], which is still high compared to immediately adjacent terrains. The most prominent thermal feature in Marcia is the pitted terrain on its floor [8]. Temperatures of the pitted floor of Marcia are significantly lower than in the surrounding terrains, when observed under similar solar illumination. Denevi et al. [4] argued that the morphology and geologic setting are consistent with rapid degassing of volatile-bearing materials following an impact, which would lead to an increased local density and/or a higher thermal conductivity [8]. References: [1] Russell et al. (2007), Earth Moon Planets 101; [2] Williams et al. (2014), submitted to Icarus; [3] Scully et al. (2013), LPSC 45; [4] Denevi et al. (2012), Science 338; [5] Williams, D.A., et al. (2013) PSS, in press, j.pss.2013.06.017 [6] De Sanctis et al. (2012b) Astrophys. J. Lett. 758; [7] Prettyman et al. (2012), Science 338; [8] Tosi et al. (2014), submitted to Icarus; [9] Konopliv et al. (2013) Icarus, in press; [10] Yamashita et al. (2013), Met. Planet. Sci. 48; [11] Prettyman et al. (2013), Met. Planet. Sci. 48; [12] Reddy et al. (2012), Science 336

Introduction to Department of Defense Research on Burn Pits, Biomarkers, and Health Outcomes Related to Deployment in Iraq and Afghanistan.

PubMed

Mallon, Col Timothy M; Rohrbeck, Maj Patricia; Haines, Maj Kevin M; Jones, Dean P; Utell, Mark; Hopke, Philip K; Phipps, Richard P; Walker, Douglas I; Thatcher, Thomas; Woeller, Collynn F; Baird, Coleen P; Pollard, Harvey B; Dalgard, Clifton L; Gaydos, Joel C

2016-08-01

This paper provides an overview of our study that was designed to assess the health impact of environmental exposures to open pit burning in deployed troops. The rationale for the study and the structure of the research plan was laid out. An overview of each article in the supplement was provided. The cohort of deployed Service members was assessed for airborne exposure, relevant biomarkers, and health outcomes following deployment to Balad, Iraq, and/or Bagram, Afghanistan. Polycyclic aromatic hydrocarbon (PAH) exposures were elevated, and serum biomarkers were statistically different postdeployment. Associations were noted between PAHs and dioxins and microRNAs. Some health outcomes were evident in deployers compared with nondeployers. Future research will examine the associations between demographic variables, smoking status, biomarker levels, and related health outcomes.

Molecular cloning, expression and purification of L-amino acid oxidase from the Malayan pit viper Calloselasma rhodostoma.

PubMed

Kommoju, Phaneeswara Rao; Macheroux, Peter; Ghisla, Sandro

2007-03-01

A cDNA encoding LAAO from the Malayan pit viper (Calloselasma rhodostoma) was cloned into an expression vector of the methylotropic yeast Pichia pastoris. The LAAO open reading frame was inserted after the alpha-MF-signal sequence. Upon induction soluble and active LAAO is produced and exported into the culture supernatant at a concentration of up to 0.4 mg/L. Recombinant LAAO was purified from this by ion exchange and molecular sieve chromatography to yield apparently homogeneous protein in quantities of approximately 0.25 mg/L growth medium. Expressed LAAO exhibits the same electrophoretic mobility as native LAAO (62 kDa) and exhibits approximately the same extent of glycosylation as authentic LAAO from snake venom. Catalytic properties and substrate specificity of recombinant LAAO are similar to those of native enzyme.

Application of Hydrophilic Silanol-Based Chemical Grout for Strengthening Damaged Reinforced Concrete Flexural Members

PubMed Central

Ju, Hyunjin; Lee, Deuck Hang; Cho, Hae-Chang; Kim, Kang Su; Yoon, Seyoon; Seo, Soo-Yeon

2014-01-01

In this study, hydrophilic chemical grout using silanol (HCGS) was adopted to overcome the performance limitations of epoxy materials used for strengthening existing buildings and civil engineering structures. The enhanced material performances of HCGS were introduced, and applied to the section enlargement method, which is one of the typical structural strengthening methods used in practice. To evaluate the excellent structural strengthening performance of the HCGS, structural tests were conducted on reinforced concrete beams, and analyses on the flexural behaviors of test specimens were performed by modified partial interaction theory (PIT). In particular, to improve the constructability of the section enlargement method, an advanced strengthening method was proposed, in which the precast panel was directly attached to the bottom of the damaged structural member by HCGS, and the degree of connection of the test specimens, strengthened by the section enlargement method, were quantitatively evaluated by PIT-based analysis. PMID:28788708

A noncontact force sensor based on a fiber Bragg grating and its application for corrosion measurement.

PubMed

Pacheco, Clara J; Bruno, Antonio C

2013-08-29

A simple noncontact force sensor based on an optical fiber Bragg grating attached to a small magnet has been proposed and built. The sensor measures the force between the magnet and any ferromagnetic material placed within a few millimeters of the sensor. Maintaining the sensor at a constant standoff distance, material loss due to corrosion increases the distance between the magnet and the corroded surface, which decreases the magnetic force. This will decrease the strain in the optical fiber shifting the reflected Bragg wavelength. The measured shift for the optical fiber used was 1.36 nm per Newton. Models were developed to optimize the magnet geometry for a specific sensor standoff distance and for particular corrosion pit depths. The sensor was able to detect corrosion pits on a fuel storage tank bottom with depths in the sub-millimeter range.

Application of Hydrophilic Silanol-Based Chemical Grout for Strengthening Damaged Reinforced Concrete Flexural Members.

PubMed

Ju, Hyunjin; Lee, Deuck Hang; Cho, Hae-Chang; Kim, Kang Su; Yoon, Seyoon; Seo, Soo-Yeon

2014-06-23

In this study, hydrophilic chemical grout using silanol (HCGS) was adopted to overcome the performance limitations of epoxy materials used for strengthening existing buildings and civil engineering structures. The enhanced material performances of HCGS were introduced, and applied to the section enlargement method, which is one of the typical structural strengthening methods used in practice. To evaluate the excellent structural strengthening performance of the HCGS, structural tests were conducted on reinforced concrete beams, and analyses on the flexural behaviors of test specimens were performed by modified partial interaction theory (PIT). In particular, to improve the constructability of the section enlargement method, an advanced strengthening method was proposed, in which the precast panel was directly attached to the bottom of the damaged structural member by HCGS, and the degree of connection of the test specimens, strengthened by the section enlargement method, were quantitatively evaluated by PIT-based analysis.

A Noncontact Force Sensor Based on a Fiber Bragg Grating and Its Application for Corrosion Measurement

PubMed Central

Pacheco, Clara J.; Bruno, Antonio C.

2013-01-01

A simple noncontact force sensor based on an optical fiber Bragg grating attached to a small magnet has been proposed and built. The sensor measures the force between the magnet and any ferromagnetic material placed within a few millimeters of the sensor. Maintaining the sensor at a constant standoff distance, material loss due to corrosion increases the distance between the magnet and the corroded surface, which decreases the magnetic force. This will decrease the strain in the optical fiber shifting the reflected Bragg wavelength. The measured shift for the optical fiber used was 1.36 nm per Newton. Models were developed to optimize the magnet geometry for a specific sensor standoff distance and for particular corrosion pit depths. The sensor was able to detect corrosion pits on a fuel storage tank bottom with depths in the sub-millimeter range. PMID:23995095

Photopolarimetry of scattering surfaces and their interpretation by computer model

NASA Technical Reports Server (NTRS)

Wolff, M.

1979-01-01

Wolff's computer model of a rough planetary surface was simplified and revised. Close adherence to the actual geometry of a pitted surface and the inclusion of a function for diffuse light resulted in a quantitative model comparable to observations by planetary satellites and asteroids. A function is also derived to describe diffuse light emitted from a particulate surface. The function is in terms of the indices of refraction of the surface material, particle size, and viewing angles. Computer-generated plots describe the observable and theoretical light components for the Moon, Mercury, Mars and a spectrum of asteroids. Other plots describe the effects of changing surface material properties. Mathematical results are generated to relate the parameters of the negative polarization branch to the properties of surface pitting. An explanation is offered for the polarization of the rings of Saturn, and the average diameter of ring objects is found to be 30 to 40 centimeters.

Palaeoecological caracterisation of the mammoth steppe at Final Pleistocene in Central Ukraine from zooarchaeology, stable isotope analyses and direct radiocarbon dating

NASA Astrophysics Data System (ADS)

Péan, Stéphane; Drucker, Dorothée.; Bocherens, Hervé; Haesaerts, Paul; Valladas, Hélène; Stupak, Dmytro; Nuzhnyi, Dmytro

2010-05-01

In the Central Ukraine area of the Middle Dnipro Basin, including the Desna river valley, there are exceptional Upper Palaeolithic open air sites with mammoth bone dwelling structures. Mezhyrich is one of these settlements, which are attributed to the Epigravettian cultural facies and occurred in a periglacial environment, during Oxygen Isotope Stage (OIS) 2. Mammoth bone buildings are surrounded by pits, which are filled with archaeological material (tools, hunting weapons, ivory and bone ornaments) and bones of mammoth and other large mammals such as hare, fox, wolf, horse. A new site Buzhanka 2 has yielded a pit which could be related to an expected dwelling structure. These Final Pleistocene sites are particularly appropriate to shed new light upon the relation between man and environment at the time of the mammoth steppe disappearance. Multidisciplinar studies have been carried on, to cross results from zooarchaeology of the pit contents, carbon and nitrogen stable isotope (13C and 15N) analyses of bone collagen, direct 14C dates on mammal bones and microstratigraphic analyses of the loessic sediment. With almost twenty 14C dates available, from mammoth and wolf bones and from charcoals, Mezhyrich is the best dated Epigravettian mammoth bone dwelling site: around 14 500 years BP. Mammoth treatment is zooarchaeologically evidenced in Buzhanka 2, but limited excavated areas do not allow to interpret their procurement yet. In Mezhyrich, consumption of mammoth meat is evidenced from the pit contents, coming from a few juveniles and young adults, probably hunted. The bones used in the dwelling structure no. 4, which are attributed to at least 37 individuals, have two different origins: mostly isolated elements gathered from other deposits, natural accumulations or previous kill sites; a few skeletal portions in anatomical position taken from at least one quite freshly dead mammoth body, for instance a hunted individual. From the stable isotope analyses, it appears that a modification of the regional plant and climatic context may have inferred a change of food resource for mammoths, which could have been put into food competition with horses. Mammoths from Central Ukraine at late OIS 2 may have formed an isolated local population, under the pressure of modified ecological conditions, compared to the period of maximal extension of the mammoth steppe. Thus, thanks to a combined approach of zooarchaeology, stable isotopes and radiocarbon dating, in the stratigraphic context, a better knowledge of the palaeoecological context of the last mammoths at late Pleniglacial in Central Ukraine is expected.

Non-destructive measurement and role of surface residual stress monitoring in residual life assessment of a steam turbine blading material

NASA Astrophysics Data System (ADS)

Prabhu-Gaunkar, Gajanana; Rawat, M. S.; Prasad, C. R.

2014-02-01

Steam turbine blades in power generation equipment are made from martensitic stainless steels having high strength, good toughness and corrosion resistance. However, these steels are susceptible to pitting which can promote early failures of blades in the turbines, particularly in the low pressure dry/wet areas by stress corrosion and corrosion fatigue. Presence of tensile residual stresses is known to accelerate failures whereas compressive stresses can help in delaying failures. Shot peening has been employed as an effective tool to induce compressive residual stresses which offset a part of local surface tensile stresses in the surface layers of components. Maintaining local stresses at stress raisers, such as pits formed during service, below a threshold level can help in preventing the initiation microcracks and failures. The thickness of the layer in compression will, however, depend of the shot peening parameters and should extend below the bottom of corrosion pits. The magnitude of surface compressive drops progressively during service exposure and over time the effectiveness of shot peening is lost making the material susceptible to micro-crack initiation once again. Measurement and monitoring of surface residual stress therefore becomes important for assessing residual life of components in service. This paper shows the applicability of surface stress monitoring to life assessment of steam turbine blade material based on data generated in laboratory on residual surface stress measurements in relation to fatigue exposure. An empirical model is proposed to calculate the remaining life of shot peened steam turbine blades in service.

Radiocarbon dating of extinct fauna in the Americas recovered from tar pits

NASA Astrophysics Data System (ADS)

Jull, A. J. T.; Iturralde-Vinent, M.; O'Malley, J. M.; MacPhee, R. D. E.; McDonald, H. G.; Martin, P. S.; Moody, J.; Rincón, A.

2004-08-01

We have obtained radiocarbon dates by accelerator mass spectrometry on bones of extinct large mammals from tar pits. Results on some samples of Glyptodon and Holmesina (extinct large mammals similar to armadillos) yielded ages of >25 and >21 ka, respectively. We also studied the radiocarbon ages of three different samples of bones from the extinct Cuban ground sloth, Parocnus bownii, which yielded dates ranging from 4960 ± 280 to 11 880 ± 420 yr BP. In order to remove the tar component pretreat the samples sufficiently to obtain reliable dates, we cleaned the samples by Soxhlet extraction in benzene. Resulting samples of collagenous material were often small.

Designing Hollow Nano Gold Golf Balls

PubMed Central

2015-01-01

Hollow/porous nanoparticles, including nanocarriers, nanoshells, and mesoporous materials have applications in catalysis, photonics, biosensing, and delivery of theranostic agents. Using a hierarchical template synthesis scheme, we have synthesized a nanocarrier mimicking a golf ball, consisting of (i) solid silica core with a pitted gold surface and (ii) a hollow/porous gold shell without silica. The template consisted of 100 nm polystyrene beads attached to a larger silica core. Selective gold plating of the core followed by removal of the polystyrene beads produced a golf ball-like nanostructure with 100 nm pits. Dissolution of the silica core produced a hollow/porous golf ball-like nanostructure. PMID:24937196

Volume Measurements of Laser-generated Pits for in Situ Geochronology Using KArLE (Potassium-Argon Laser Experiment)

NASA Technical Reports Server (NTRS)

French, R. A.; Cohen, B. A.; Miller, J. S.

2014-01-01

KArLE (Potassium-­-Argon Laser Experiment) has been developed for in situ planetary geochronology using the K - Ar (potassium-­-argon) isotope system, where material ablated by LIBS (Laser-­-Induced Breakdown Spectroscopy) is used to calculate isotope abundances. We are determining the accuracy and precision of volume measurements of these pits using stereo and laser microscope data to better understand the ablation process for isotope abundance calculations. If a characteristic volume can be determined with sufficient accuracy and precision for specific rock types, KArLE will prove to be a useful instrument for future planetary rover missions.

Correction: Alvarado, M., et al. Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites. Sensors 2015, 15, 19667-19687.

PubMed

Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

2016-07-05

The author wishes to change Figure 1 and Figure 3 from his paper published in Sensors [1], doi:10.3390/s150819667, website: http://www.mdpi.com/1424-8220/15/8/19667 for Figures 1 and 2 presented in this 'Correction'.[...].

The Study of Soil Protection in the System of the Cultivated Lands of Kemerovo Region

NASA Astrophysics Data System (ADS)

Yakovchenko, M. A.; Konstantinova, O. B.; Kosolapova, A. A.

2015-09-01

The heavy metal content in the surface soils is characterized with their ingress for the given period of time. The sources of heavy metals in the soil are precipitation, seeds, dust, organic and mineral fertilizers, and others. The paper studies the heavy metal content in the soils of the waste dumps of the open-pit coal mines.

USE OF ENVIRONMENTAL ISOTOPES TO DIFFERENTIATE WATER SOURCES AND CONSTRAIN THE WATER BUDGET AT THE SULPHUR BANK MERCURY MINE, CLEAR LAKE, CALIFORNIA

EPA Science Inventory

The Sulphur Bank Mercury Mine (SBMM) is a 65 ha site located on the eastern shore of the Oaks Arm of Clear Lake, Lake County, California. Between 1864 and 1957, SBMM was the site of underground and open pit mining operations for S and Hg, coinciding with past and present hot spr...

Getty: producing oil from diatomite

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

Zublin, L.

1981-10-01

Getty Oil Company has developed unconventional oil production techniques which will yield oil from diatomaceous earth. They propose to mine oil-saturated diatomite using open-pit mining methods. Getty's diatomite deposit in the McKittrick field of California is unique because it is cocoa brown and saturated with crude oil. It is classified also as a tightly packed deposit, and oil cannot be extracted by conventional oil field methods.

Cytogenetic instability in populations with residential proximity to open-pit coal mine in Northern Colombia in relation to PM10 and PM2.5 levels.

PubMed

Espitia-Pérez, Lyda; da Silva, Juliana; Espitia-Pérez, Pedro; Brango, Hugo; Salcedo-Arteaga, Shirley; Hoyos-Giraldo, Luz Stella; de Souza, Claudia T; Dias, Johnny F; Agudelo-Castañeda, Dayana; Valdés Toscano, Ana; Gómez-Pérez, Miguel; Henriques, João A P

2018-02-01

Epidemiological studies indicate that living in proximity to coal mines is correlated with numerous diseases including cancer, and that exposure to PM 10 and PM 2.5 components could be associated with this phenomenon. However, the understanding of the mechanisms by which PM exerts its adverse effects is still incomplete and comes mainly from studies in occupationally exposed populations. The aims of this study were to: (1) evaluate DNA damage in lymphocytes assessing the cytokinesis-block micronucleus cytome assay (CBMN-cyt) parameters; (2) identify aneugenic or clastogenic effects in lymphocytes of exposed populations using CREST immunostaining for micronuclei; (3) evaluate multi-elemental composition of atmospheric particulate matter; and (4) verify relation between the DNA damage and PM 2.5 and PM 10 levels around the mining area. Analysis revealed a significant increase in micronuclei frequency in binucleated (MNBN) and mononucleated (MNMONO) cells of individuals with residential proximity to open-pit coal mines compared to residents from non-mining areas. Correlation analysis demonstrated a highly significant association between PM 2.5 levels, MNBN frequencies and CREST+ micronuclei induction in exposed residents. These results suggest that PM 2.5 fraction generated in coal mining activities may induce whole chromosome loss (aneuploidy) preferentially, although there are also chromosome breaks. Analysis of the chemical composition of PM 2.5 by PIXE demonstrated that Si, S, K and Cr concentrations varied significantly between coal mining and reference areas. Enrichment factor values (EF) showed that S, Cr and Cu were highly enriched in the coal mining areas. Compared to reference area, mining regions had also higher concentrations of extractable organic matter (EOM) related to nonpolar and polar compounds. Our results demonstrate that PM 2.5 fraction represents the most important health risk for residents living near open-pit mines, underscoring the need for incorporation of ambient air standards based on PM 2.5 measures in coal mining areas. Copyright © 2017. Published by Elsevier Inc.

February 2011 sensitive clay landslides at the Çöllolar coalfield, eastern Turkey

NASA Astrophysics Data System (ADS)

Akçar, Naki; Yavuz, Vural; Ivy-Ochs, Susan; Nyffenegger, Franziska; Fredin, Ola; Stolz, Martin; Schlunegger, Fritz

2016-04-01

The Elbistan basin is an intramontane basin, which is located in the eastern Turkey and bound by the Taurus and Antitaurus Mountains. The basin covers an area of 900 km² at a mean elevation of about 1200 m. The basement rock in this field is karstic limestone, which is overlain by a thick layer of clay (>100 m), followed by 20-50 m thick Lignite series that is overlain by the 20-50 m thick Gyttja sequence. These deposits are overlain by Quaternary deposits, comprising the top surfaces of the terraces of the Hurman River, which drains the surface and ground water from the surrounding hills to the northeast towards the center of the Elbistan basin. The Çöllolar open pit mine, situated in the northwestern sector of the Elbistan basin, contains 90 km2 of mineable coal which has been excavated since 2008. In February 2011, two landslides in which 10 workers were killed, occurred in this field. Of the two landslides, the 2nd and largest which covers an area of ca. 2.3 km2,was caused by the collapse of the northeastern wall of the open-pit mine. The failure was made of successive rearward collapses with the debris flowing into the open-pit. In this study, we focus on the geologic factors that led to instability and the trigger of the landslides. To reveal these factors, we employ sedimentological and geotechnical analysis of deposits, with a special emphasis on the Pliocene lacustrine carbonaceous sediments and the sensitivity of the overlying Quaternary clays. First results from the fieldwork and the mineralogical composition and physical properties of the collected samples indicate that the landslide was caused by the liquefaction of one of the layers within the thick sequence of this part of the Elbistan basin based on the flow style of the movement and nature of the failure. In brief, we conclude that massive failures at the Çöllolar coalfield are unique examples of sensitive clay landslides occurred in a subtropical arid region beyond the extent of Quaternary glaciations.

Stability of highwalls in surface coal mines, western Powder Ridge Basin, Wyoming and Montana

USGS Publications Warehouse

Lee, Fitzhugh T.; Smith, William K.; Savage, William Z.

1976-01-01

Preliminary results from the first part of a two-part investigation of the stability of highwalls in open-pit coal mines in the Fort Union Formation of the western Powder River Basin of Wyoming and Montana indicate that these highwalls are subject to time-dependent deformation. Field investigations and laboratory physical-properties tests of coal and overburden rocks suggest that several factors influence highwall stability. Some of these factors are rebound of overconsolidated rocks, desiccation, water, orientation and spacing of fractures, and strength and deformation properties. Factors of safety for a typical highwall in the study area (calculated by the finite-element method) may be less than 1.0 when open fractures are present and the highwall has degraded. Although it is concluded that most open-pit mines in the Fort Union Formation within the study area have generally stable highwalls, these highwalls do deteriorate and become progressively less stable. Because of this, postmining failures are common and could be critical if mining were delayed and then resumed after a period of several months. The second part of the investigation will utilize field measurements of rock-mass properties and instrumentation of actively mined highwalls to obtain data for comparison with the results of the initial investigation. Because the height of highwalls will increase as the more shallow coal is exhausted, these data will also be used to predict the behavior of slopes higher than those presently found in the western Powder River Basin.

Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites

PubMed Central

Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

2015-01-01

Blasting is an integral part of large-scale open cut mining that often occurs in close proximity to population centers and often results in the emission of particulate material and gases potentially hazardous to health. Current air quality monitoring methods rely on limited numbers of fixed sampling locations to validate a complex fluid environment and collect sufficient data to confirm model effectiveness. This paper describes the development of a methodology to address the need of a more precise approach that is capable of characterizing blasting plumes in near-real time. The integration of the system required the modification and integration of an opto-electrical dust sensor, SHARP GP2Y10, into a small fixed-wing and multi-rotor copter, resulting in the collection of data streamed during flight. The paper also describes the calibration of the optical sensor with an industry grade dust-monitoring device, Dusttrak 8520, demonstrating a high correlation between them, with correlation coefficients (R2) greater than 0.9. The laboratory and field tests demonstrate the feasibility of coupling the sensor with the UAVs. However, further work must be done in the areas of sensor selection and calibration as well as flight planning. PMID:26274959

Towards the Development of a Low Cost Airborne Sensing System to Monitor Dust Particles after Blasting at Open-Pit Mine Sites.

PubMed

Alvarado, Miguel; Gonzalez, Felipe; Fletcher, Andrew; Doshi, Ashray

2015-08-12

Blasting is an integral part of large-scale open cut mining that often occurs in close proximity to population centers and often results in the emission of particulate material and gases potentially hazardous to health. Current air quality monitoring methods rely on limited numbers of fixed sampling locations to validate a complex fluid environment and collect sufficient data to confirm model effectiveness. This paper describes the development of a methodology to address the need of a more precise approach that is capable of characterizing blasting plumes in near-real time. The integration of the system required the modification and integration of an opto-electrical dust sensor, SHARP GP2Y10, into a small fixed-wing and multi-rotor copter, resulting in the collection of data streamed during flight. The paper also describes the calibration of the optical sensor with an industry grade dust-monitoring device, Dusttrak 8520, demonstrating a high correlation between them, with correlation coefficients (R(2)) greater than 0.9. The laboratory and field tests demonstrate the feasibility of coupling the sensor with the UAVs. However, further work must be done in the areas of sensor selection and calibration as well as flight planning.

The 2008 phreatomagmatic eruption of Okmok volcano, Aleutian Islands, Alaska: Chronology, deposits, and landform changes

USGS Publications Warehouse

Jessica Larsen,; Neal, Christina; Schaefer, Janet R.; Kaufman, Max; Lu, Zhong

2015-01-01

Okmok volcano, Aleutian Islands, Alaska, explosively erupted over a five-week period between July 12 and August 23, 2008. The eruption was predominantly phreatomagmatic, producing fine-grained tephra that covered most of northeastern Umnak Island. The eruption had a maximum Volcanic Explosivity Index (VEI) of 4, with eruption column heights up to 16 km during the opening phase. Several craters and a master tuff cone formed in the caldera as a result of phreatomagmatic explosions and accumulated tephra-fall and surge deposits. Ascending magma continuously interacted with an extensive shallow groundwater table in the caldera, resulting in the phreatomagmatic character of the eruption. Syneruptive explosion and collapse processes enlarged a pre-existing lake, created a second, entirely new lake, and formed new, deep craters. A field of ephemeral collapse pits and collapse escarpments formed where rapid groundwater withdrawal removed material from beneath capping lava flows. This was the first significant phreatomagmatic event in the U.S. since the Ukinrek Maars eruption in 1977.

Effect of surface texture by ion beam sputtering on implant biocompatibility and soft tissue attachment

NASA Technical Reports Server (NTRS)

Gibbons, D. F.

1977-01-01

The objectives in this report were to use the ion beam sputtering technique to produce surface textures on polymers, metals, and ceramics. The morphology of the texture was altered by varying both the width and depth of the square pits which were formed by ion beam erosion. The width of the ribs separating the pits were defined by the mask used to produce the texture. The area of the surface containing pits varies as the width was changed. The biological parameters used to evaluate the biological response to the texture were: (1) fibrous capsule and inflammatory response in subcutaneous soft tissue; (2) strength of the mechanical attachment of the textured surface by the soft tissue; and (3) morphology of the epidermal layer interfacing the textured surface of percutaneous connectors. Because the sputter yield on teflon ribs was approximately an order of magnitude larger than any other material the majority of the measurements presented in the report were obtained with teflon.

RCRA Facility Investigation/Remedial Investigation Report for Gunsite 720 Rubble Pit Unit (631-16G) - March 1996

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

Palmer, E.

1996-03-01

Gunsite 720 Rubble Pit Unit is located on the west side of SRS. In the early to mid 1980`s, while work was being performed in this area, nine empty, partially buried drums, labeled `du Pont Freon 11`, were found. As a result, Gunsite 720 became one of the original waste units specified in the SRS RCRA Facility Assessment (RFA). The drums were excavated on July 30, 1987 and placed on a pallet at the unit. Both the drums and pallet were removed and disposed of in October 1989. The area around the drums was screened during the excavation and themore » liquid (rainwater) that collected in the excavated drums was sampled prior to disposal. No evidence of hazardous materials was found. Based on the review of the analytical data and screening techniques used to evaluate all the chemicals of potential concern at Gunsite 720 Rubble Pit Unit, it is recommended that no further remedial action be performed at this unit.« less

Influence of Sulfate-Reducing Bacteria on the Corrosion Residual Strength of an AZ91D Magnesium Alloy

PubMed Central

Zhu, Xianyong; Liu, Yaohui; Wang, Qiang; Liu, Jiaan

2014-01-01

In this paper, the corrosion residual strength of the AZ91D magnesium alloy in the presence of sulfate-reducing bacteria is studied. In the experiments, the chemical composition of corrosion film was analyzed by a scanning electron microscope with energy dispersive X-ray spectroscopy. In addition, a series of instruments, such as scanning electronic microscope, pH-meter and an AG-10TA materials test machine, were applied to test and record the morphology of the corrosion product, fracture texture and mechanical properties of the AZ91D magnesium alloy. The experiments show that the sulfate-reducing bacteria (SRB) play an important role in the corrosion process of the AZ91D magnesium alloy. Pitting corrosion was enhanced by sulfate-reducing bacteria. Corrosion pits are important defects that could lead to a significant stress concentration in the tensile process. As a result, sulfate-reducing bacteria influence the corrosion residual strength of the AZ91D magnesium alloy by accelerating pitting corrosion. PMID:28788236

Hard particle effect on surface generation in nano-cutting

NASA Astrophysics Data System (ADS)

Xu, Feifei; Fang, Fengzhou; Zhang, Xiaodong

2017-12-01

The influence of the hard particle on the surface generation, plastic deformation and processing forces in nano-cutting of aluminum is investigated by means of molecular dynamics simulations. In this investigation, a hard particle which is simplified as a diamond ball is embedded under the free surface of workpiece with different depths. The influence of the position of the hard ball on the surface generation and other material removal mechanism, such as the movement of the ball under the action of cutting tool edge, is revealed. The results show that when the hard particle is removed, only a small shallow pit is left on the machined surface. Otherwise, it is pressed down to the subsurface of the workpiece left larger and deeper pit on the generated surface. Besides that, the hard particle in the workpiece would increase the processing force when the cutting tool edge or the plastic carriers interact with the hard particle. It is helpful to optimize the cutting parameters and material properties for obtaining better surface quality in nano-cutting of composites or other materials with micro/nanoscale hard particles in it.

Renewed mining and reclamation: Imapacts on bats and potential mitigation

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

Brown, P.E.; Berry, R.D.

Historic mining created new roosting habitat for many bat species. Now the same industry has the potential to adversely impact bats. Contemporary mining operations usually occur in historic districts; consequently the old workings are destroyed by open pit operations. Occasionally, underground techniques are employed, resulting in the enlargement or destruction of the original workings. Even during exploratory operations, historic mine openings can be covered as drill roads are bulldozed, or drills can penetrate and collapse underground workings. Nearby blasting associated with mine construction and operation can disrupt roosting bats. Bats can also be disturbed by the entry of mine personnelmore » to collect ore samples or by recreational mine explorers, since the creation of roads often results in easier access. In addition to roost disturbance, other aspects of renewed mining can have adverse impacts on bat populations, and affect even those bats that do not live in mines. Open cyanide ponds, or other water in which toxic chemicals accumulate, can poison bats and other wildlife. The creation of the pits, roads and processing areas often destroys critical foraging habitat, or change drainage patterns. Finally, at the completion of mining, any historic mines still open may be sealed as part of closure and reclamation activities. The net result can be a loss of bats and bat habitat. Conversely, in some contemporary underground operations, future roosting habitat for bats can be fabricated. An experimental approach to the creation of new roosting habitat is to bury culverts or old tires beneath waste rock. Mining companies can mitigate for impacts to bats by surveying to identify bat-roosting habitat, removing bats prior to renewed mining or closure, protecting non-impacted roost sites with gates and fences, researching to identify habitat requirements and creating new artificial roosts.« less

Understanding effect of 3.5 wt.% NaCl on the corrosion of Al0.1CoCrFeNi high-entropy alloy

NASA Astrophysics Data System (ADS)

Kumar, N.; Fusco, M.; Komarasamy, M.; Mishra, R. S.; Bourham, M.; Murty, K. L.

2017-11-01

High entropy alloys are a new class of metallic materials with potential for use in a wide variety of applications including their use in corrosive environment. The present study focused on the corrosion behavior of a single-phase, face-centered cubic high entropy alloy (HEA) Al0.1CoCrFeNi in as-cast condition, and the results are compared with the corrosion behavior of the SS304. The microstructural characterization of the alloys in as-received condition was carried out using optical microscopy, electron backscattered diffraction, energy dispersive spectroscopy, and X-ray diffraction. Corrosion behavior was studied using potentiodynamic polarization test in a 3.5 wt% NaCl solution and electrochemical impedance spectroscopy at room temperature. It was observed that the general corrosion resistance of the HEA was better than that of SS304. Pitting potential of the HEA was found to be superior to that of the SS304. Corrosion pits size was slightly smaller in SS304 than that in the HEA. 3D imaging determined that the pit depths were of the same order in both cases. Overall, the HEA Al0.1CoCrFeNi demonstrated a better resistance to general and pitting corrosion.

STS 8 Orbiter mission window pitting and the possible association with the El Chichon eruption of March and April 1982

NASA Technical Reports Server (NTRS)

Cour-Palais, B. G.; Kessler, D. J.; Zook, H. A.; Clanton, U. S.

1985-01-01

The possibility that the pitting that occurred in the STS-8 Orbiter windows was caused by dust from the El Chichon volcano eruption in March-April 1982 is considered. The pit density was more than 30/sq cm, most being 2.5-5 microns deep, and showed no evidence of impact melting. An 'alley' of higher incidence of pits in one window coincided with the line of a seam between TPS tiles. The particles causing the sandblasting were concluded to have arrived in parallel and could not be attributed to the ET, SRBs or a dust storm. The sulfuric gas-rich El Chichon plume injected sufficient material into the atmosphere so that the globe was soon encircled. Most of the resulting particulates (480-8400 tons) stayed in the Northern Hemisphere, and H2SO4 and ash concentrations were high during the STS-8 mission. The Orbiter cut through the debris layer at 19.8 km altitude at a 10 deg angle of attack, which matches the particle crater impact angle in the Orbiter windows. Since the passage was at night, larger H2SO4 droplets may have coalesced and formed larger particles on available solid nuclei, thus producing the 20-40 microns cratering observed in the windows.

Time effect of erosion by solid particle impingement on ductile materials

NASA Technical Reports Server (NTRS)

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

1983-01-01

Erosion and morphological studies of several metals and alloys eroded by normal impingement jets of spherical glass beads and angular crushed-glass erodent particles were conducted. Erosion morphology (the width, depth, and width-depth ratio of the pit) was studied in order to fully investigate the effect of time on erosion rate. The eroded surfaces were studied with a scanning electron microscope, and surface profiles were measured with a profilometer. A large amount of experimental data reported in the literature was also analyzed in order to understand the effect of variables such as the type of device, the erodent particle size and shape, the impact velocity, and the abrasive charge on erosion-rate-versus-time curves. In the present experiments the pit-width-versus-time or pit-depth-versus-time curves were similar to erosion-versus-time curves for glass-bead impingement. The pit-depth-rate-versus-time curves were similar to erosion-rate-versus-time curves for crushed-glass impingement. Analysis of experimental data with two forms of glass resulted in four types of erosion-rate-versus-time curves: (1) incubation, acceleration, and steady-state periods (type I), (2) incubation, acceleration, deceleration, and steady-state periods (type III), (3) incubation, acceleration, peak rate, and deceleration periods (type IV), and (4) incubation, acceleration, steady-state, and deceleration periods (type V).

Sodium-dependent phosphate cotransporters and phosphate-induced calcification of vascular smooth muscle cells: Redundant roles for PiT-1 and PiT-2

PubMed Central

Crouthamel, Matthew H.; Lau, Wei Ling; Leaf, Elizabeth M.; Chavkin, Nick; Wallingford, Mary C.; Peterson, Danielle F.; Li, Xianwu; Liu, Yonggang; Chin, Michael T.; Levi, Moshe; Giachelli, Cecilia M.

2014-01-01

Objective Elevated serum phosphate has emerged as a major risk factor for vascular calcification. The sodium-dependent phosphate cotransporter, PiT-1, was previously shown to be required for phosphate-induced osteogenic differentiation and calcification of cultured human VSMCs, but its importance in vascular calcification in vivo, as well as the potential role of its homologue, PiT-2, have not been determined. We investigated the in vivo requirement for PiT-1 in vascular calcification using a mouse model of chronic kidney disease, and the potential compensatory role of PiT-2 using in vitro knockdown and over-expression strategies. Approach and Results Mice with targeted deletion of PiT-1 in VSMCs were generated (PiT-1Δsm). PiT-1 mRNA levels were undetectable whereas PiT-2 mRNA levels were increased 2 fold in the vascular aortic media of PiT-1Δsm compared to PiT-1flox/flox control. When arterial medial calcification was induced in PiT-1Δsm and PiT-1flox/flox by chronic kidney disease followed by dietary phosphate loading, the degree of aortic calcification was not different between genotypes, suggesting compensation by PiT-2. Consistent with this possibility, VSMCs isolated from PiT-1Δsm mice had no PiT-1 mRNA expression, increased PiT-2 mRNA levels, and no difference in sodium-dependent phosphate uptake or phosphate-induced matrix calcification compared to PiT-1flox/flox VSMCs. Knockdown of PiT-2 decreased phosphate uptake and phosphate-induced calcification of PiT-1Δsm VSMCs. Furthermore, over-expression of PiT-2 restored these parameters in human PiT-1-deficient VSMCs. Conclusions PiT-2 can mediate phosphate uptake and calcification of VSMCs in the absence of PiT-1. Mechanistically, PiT-1 and PiT-2 appear to serve redundant roles in phosphate-induced calcification of vascular smooth muscle cells. PMID:23968976

Craters on comets

NASA Astrophysics Data System (ADS)

Vincent, J.; Oklay, N.; Marchi, S.; Höfner, S.; Sierks, H.

2014-07-01

This paper reviews the observations of crater-like features on cometary nuclei. ''Pits'' have been observed on almost all cometary nuclei but their origin is not fully understood [1,2,3,4]. It is currently assumed that they are created mainly by the cometary activity with a pocket of volatiles erupting under a dust crust, leaving a hole behind. There are, however, other features which cannot be explained in this way and are interpreted alternatively as remnants of impact craters. This work focusses on the second type of pit features: impact craters. We present an in-depth review of what has been observed previously and conclude that two main types of crater morphologies can be observed: ''pit-halo'' and ''sharp pit''. We extend this review by a series of analysis of impact craters on cometary nuclei through different approaches [5]: (1) Probability of impact: We discuss the chances that a Jupiter Family Comet like 9P/Tempel 1 or the target of Rosetta 67P/Churyumov-Gerasimenko can experience an impact, taking into account the most recent work on the size distribution of small objects in the asteroid Main Belt [6]. (2) Crater morphology from scaling laws: We present the status of scaling laws for impact craters on cometary nuclei [7] and discuss their strengths and limitations when modeling what happens when a rocky projectile hits a very porous material. (3) Numerical experiments: We extend the work on scaling laws by a series of hydrocode impact simulations, using the iSALE shock physics code [8,9,10] for varying surface porosity and impactor velocity (see Figure). (4) Surface processes and evolution: We discuss finally the fate of the projectile and the effects of the impact-induced surface compaction on the activity of the nucleus. To summarize, we find that comets do undergo impacts although the rapid evolution of the surface erases most of the features and make craters difficult to detect. In the case of a collision between a rocky body and a highly porous cometary nucleus, two specific crater morphologies can be formed: a central pit surrounded by a shallow depression, or a pit, deeper than typical craters observed on rocky surfaces. After the impact, it is likely that a significant fraction of the projectile will remain in the crater. During its two years long escort of comet 67P/Churyumov-Gerasimenko, ESA's Rosetta mission should be able to detect specific silicate signatures on the bottom of craters or crater-like features, as evidence of this contamination. For large craters, structural changes in the impacted region, in particular, compaction of material, will affect the local activity. The increase of tensile strength can stop the activity by preventing the gas from lifting up dust grains. On the other hand, material compaction can help the heat flux to travel deeper in the nucleus, potentially reaching unexposed pockets of volatiles, and therefore increasing the activity [11]. Ground truth data from Rosetta will help us infer the relative importance of those two effects.

A novel pit pattern identifies the precursor of colorectal cancer derived from sessile serrated adenoma.

PubMed

Kimura, Tomoaki; Yamamoto, Eiichiro; Yamano, Hiro-O; Suzuki, Hiromu; Kamimae, Seiko; Nojima, Masanori; Sawada, Takeshi; Ashida, Masami; Yoshikawa, Kenjiro; Takagi, Ryo; Kato, Ryusuke; Harada, Taku; Suzuki, Ryo; Maruyama, Reo; Kai, Masahiro; Imai, Kohzoh; Shinomura, Yasuhisa; Sugai, Tamotsu; Toyota, Minoru

2012-03-01

Sessile serrated adenomas (SSAs) are known to be precursors of sporadic colorectal cancers (CRCs) with microsatellite instability (MSI), and to be tightly associated with BRAF mutation and the CpG island methylator phenotype (CIMP). Consequently, colonoscopic identification of SSAs has important implications for preventing CRCs, but accurate endoscopic diagnosis is often difficult. Our aim was to clarify which endoscopic findings are specific to SSAs. The morphological, histological and molecular features of 261 specimens from 226 colorectal tumors were analyzed. Surface microstructures were analyzed using magnifying endoscopy. Mutation in BRAF and KRAS was examined by pyrosequencing. Methylation of p16, IGFBP7, MLH1 and MINT1, -2, -12 and -31 was analyzed using bisulfite pyrosequencing. Through retrospective analysis of a training set (n=145), we identified a novel surface microstructure, the Type II open-shape pit pattern (Type II-O), which was specific to SSAs with BRAF mutation and CIMP. Subsequent prospective analysis of an independent validation set (n=116) confirmed that the Type II-O pattern is highly predictive of SSAs (sensitivity, 65.5%; specificity, 97.3%). BRAF mutation and CIMP occurred with significant frequency in Type II-O-positive serrated lesions. Progression of SSAs to more advanced lesions was associated with further accumulation of aberrant DNA methylation and additional morphological changes, including the Type III, IV and V pit patterns. Our results suggest the Type II-O pit pattern is a useful hallmark of the premalignant stage of CRCs with MSI and CIMP, which could serve to improve the efficacy of colonoscopic surveillance.

Assessment of factors limiting algal growth in acidic pit lakes--a case study from Western Australia, Australia.

PubMed

Kumar, R Naresh; McCullough, Clint D; Lund, Mark A; Larranaga, Santiago A

2016-03-01

Open-cut mining operations can form pit lakes on mine closure. These new water bodies typically have low nutrient concentrations and may have acidic and metal-contaminated waters from acid mine drainage (AMD) causing low algal biomass and algal biodiversity. A preliminary study was carried out on an acidic coal pit lake, Lake Kepwari, in Western Australia to determine which factors limited algal biomass. Water quality was monitored to obtain baseline data. pH ranged between 3.7 and 4.1, and solute concentrations were slightly elevated to levels of brackish water. Concentrations of N were highly relative to natural lakes, although concentrations of FRP (<0.01 mg/L) and C (total C 0.7-3.7 and DOC 0.7-3.5 mg/L) were very low, and as a result, algal growth was also extremely low. Microcosm experiment was conducted to test the hypothesis that nutrient enrichment will be able to stimulate algal growth regardless of water quality. Microcosms of Lake Kepwari water were amended with N, P and C nutrients with and without sediment. Nutrient amendments under microcosm conditions could not show any significant phytoplankton growth but was able to promote benthic algal growth. P amendments without sediment showed a statistically higher mean algal biomass concentration than controls or microcosms amended with phosphorus but with sediment did. Results indicated that algal biomass in acidic pit lake (Lake Kepwari) may be limited primarily by low nutrient concentrations (especially phosphorus) and not by low pH or elevated metal concentrations. Furthermore, sediment processes may also reduce the nutrient availability.

Metagenomic investigation of the microbial diversity in a chrysotile asbestos mine pit pond, Lowell, Vermont, USA.

PubMed

Driscoll, Heather E; Vincent, James J; English, Erika L; Dolci, Elizabeth D

2016-12-01

Here we report on a metagenomics investigation of the microbial diversity in a serpentine-hosted aquatic habitat created by chrysotile asbestos mining activity at the Vermont Asbestos Group (VAG) Mine in northern Vermont, USA. The now-abandoned VAG Mine on Belvidere Mountain in the towns of Eden and Lowell includes three open-pit quarries, a flooded pit, mill buildings, roads, and > 26 million metric tons of eroding mine waste that contribute alkaline mine drainage to the surrounding watershed. Metagenomes and water chemistry originated from aquatic samples taken at three depths (0.5 m, 3.5 m, and 25 m) along the water column at three distinct, offshore sites within the mine's flooded pit (near 44°46'00.7673″, - 72°31'36.2699″; UTM NAD 83 Zone 18 T 0695720 E, 4960030 N). Whole metagenome shotgun Illumina paired-end sequences were quality trimmed and analyzed based on a translated nucleotide search of NCBI-NR protein database and lowest common ancestor taxonomic assignments. Our results show strata within the pit pond water column can be distinguished by taxonomic composition and distribution, pH, temperature, conductivity, light intensity, and concentrations of dissolved oxygen. At the phylum level, metagenomes from 0.5 m and 3.5 m contained a similar distribution of taxa and were dominated by Actinobacteria (46% and 53% of reads, respectively), Proteobacteria (45% and 38%, respectively), and Bacteroidetes (7% in both). The metagenomes from 25 m showed a greater diversity of phyla and a different distribution of reads than the two upper strata: Proteobacteria (60%), Actinobacteria (18%), Planctomycetes, (10%), Bacteroidetes (5%) and Cyanobacteria (2.5%), Armatimonadetes (< 1%), Verrucomicrobia (< 1%), Firmicutes (< 1%), and Nitrospirae (< 1%). Raw metagenome sequence data from each sample reside in NCBI's Short Read Archive (SRA ID: SRP056095) and are accessible through NCBI BioProject PRJNA277916.

Nobody’s perfect: can irregularities in pit structure influence vulnerability to cavitation?

PubMed Central

Plavcová, Lenka; Jansen, Steven; Klepsch, Matthias; Hacke, Uwe G.

2013-01-01

Recent studies have suggested that species-specific pit properties such as pit membrane thickness, pit membrane porosity, torus-to-aperture diameter ratio and pit chamber depth influence xylem vulnerability to cavitation. Despite the indisputable importance of using mean pit characteristics, considerable variability in pit structure within a single species or even within a single pit field should be acknowledged. According to the rare pit hypothesis, a single pit that is more air-permeable than many neighboring pits is sufficient to allow air-seeding. Therefore, any irregularities or morphological abnormalities in pit structure allowing air-seeding should be associated with increased vulnerability to cavitation. Considering the currently proposed models of air-seeding, pit features such as rare, large pores in the pit membrane, torus extensions, and plasmodesmatal pores in a torus can represent potential glitches. These aberrations in pit structure could either result from inherent developmental flaws, or from damage caused to the pit membrane by chemical and physical agents. This suggests the existence of interesting feedbacks between abiotic and biotic stresses in xylem physiology. PMID:24273549

Impact Cratering Processes as Understood Through Martian and Terrestrial Analog Studies

NASA Astrophysics Data System (ADS)

Caudill, C. M.; Osinski, G. R.; Tornabene, L. L.

2016-12-01

Impact ejecta deposits allow an understanding of subsurface lithologies, volatile content, and other compositional and physical properties of a planetary crust, yet development and emplacement of these deposits on terrestrial bodies throughout the solar system is still widely debated. Relating relatively well-preserved Martian ejecta to terrestrial impact deposits is an area of active research. In this study, we report on the mapping and geologic interpretation of 150-km diameter Bakhuysen Crater, Mars, which is likely large enough to have produced a significant volume of melt, and has uniquely preserved ejecta deposits. Our mapping supports the current formation hypothesis for Martian crater-related pitted material, where pits are likened to collapsed degassing features identified at the Ries and Haughton terrestrial impact structures. As hot impact melt-bearing ejecta deposits are emplaced over volatile-saturated material during crater formation, a rapid degassing of the underlying layer results in lapilli-like fluid and gas flow pipes which may eventually lead to collapse features on the surface. At the Haughton impact structure, degassing pipes are related to crater fracture and fault systems; this is analogous to structure and collapse pits mapped in Bakhuysen Crater. Based on stratigraphic superposition, surface and flow texture, and morphological and thermophysical mapping of Bakhuysen, we interpret the top-most ejecta unit to be likely melt-bearing and analogous to terrestrial impact deposits (e.g., Ries suevites). Furthermore, we suggest that Chicxulub is an apt terrestrial comparison based on its final diameter and the evidence of a ballistically-emplaced and volatile-entrained initial ejecta. This is significant as Bakhuysen ejecta deposits may provide insight into larger impact structures where limited exposures make studies difficult. This supports previous work which suggests that given similarities in volatile content and subsurface stratigraphy, mechanisms of multi-unit ejecta emplacement extend to impact cratering processes on comparable rocky bodies. The widespread pitted material, ejecta rampart and lobe formations, and distal debris flows associated with Bakhuysen impactite emplacement further indicates a volatile-rich Martian crust during its formation.

Advances in dental materials.

PubMed

Vaderhobli, Ram M

2011-07-01

The use of materials to rehabilitate tooth structures is constantly changing. Over the past decade, newer material processing techniques and technologies have significantly improved the dependability and predictability of dental material for clinicians. The greatest obstacle, however, is in choosing the right combination for continued success. Finding predictable approaches for successful restorative procedures has been the goal of clinical and material scientists. This article provides a broad perspective on the advances made in various classes of dental restorative materials in terms of their functionality with respect to pit and fissure sealants, glass ionomers, and dental composites. Copyright © 2011 Elsevier Inc. All rights reserved.

Application of Three Existing Stope Boundary Optimisation Methods in an Operating Underground Mine

NASA Astrophysics Data System (ADS)

Erdogan, Gamze; Yavuz, Mahmut

2017-12-01

The underground mine planning and design optimisation process have received little attention because of complexity and variability of problems in underground mines. Although a number of optimisation studies and software tools are available and some of them, in special, have been implemented effectively to determine the ultimate-pit limits in an open pit mine, there is still a lack of studies for optimisation of ultimate stope boundaries in underground mines. The proposed approaches for this purpose aim at maximizing the economic profit by selecting the best possible layout under operational, technical and physical constraints. In this paper, the existing three heuristic techniques including Floating Stope Algorithm, Maximum Value Algorithm and Mineable Shape Optimiser (MSO) are examined for optimisation of stope layout in a case study. Each technique is assessed in terms of applicability, algorithm capabilities and limitations considering the underground mine planning challenges. Finally, the results are evaluated and compared.

Breaking Ground on the Moon and Mars: Reconstructing Lunar Tectonic Evolution and Martian Central Pit Crater Formation

NASA Astrophysics Data System (ADS)

Williams, Nathan Robert

Understanding the structural evolution of planetary surfaces provides key insights to their physical properties and processes. On the Moon, large-scale tectonism was thought to have ended over a billion years ago. However, new Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) high resolution images show the Moon's surface in unprecedented detail and show many previously unidentified tectonic landforms, forcing a re-assessment of our views of lunar tectonism. I mapped lobate scarps, wrinkle ridges, and graben across Mare Frigoris -- selected as a type area due to its excellent imaging conditions, abundance of tectonic landforms, and range of inferred structural controls. The distribution, morphology, and crosscutting relationships of these newly identified populations of tectonic landforms imply a more complex and longer-lasting history of deformation that continues to today. I also performed additional numerical modeling of lobate scarp structures that indicates the upper kilometer of the lunar surface has experienced 3.5-18.6 MPa of differential stress in the recent past, likely due to global compression from radial thermal contraction. Central pit craters on Mars are another instance of intriguing structures that probe subsurface physical properties. These kilometer-scale pits are nested in the centers of many impact craters on Mars as well as on icy satellites. They are inferred to form in the presence of a water-ice rich substrate; however, the process(es) responsible for their formation is still debated. Previous models invoke origins by either explosive excavation of potentially water-bearing crustal material, or by subsurface drainage of meltwater and/or collapse. I assessed radial trends in grain size around central pits using thermal inertias calculated from Thermal Emission Imaging System (THEMIS) thermal infrared images. Average grain size decreases with radial distance from pit rims -- consistent with pit-derived ejecta but not expected for collapse models. I present a melt-contact model that might enable a delayed explosion, in which a central uplift brings ice-bearing substrate into contact with impact melt to generate steam explosions and excavate central pits during the impact modification stage.

Isotope biogeochemical assessment of natural biodegradation processes in open cast pit mining landscapes

NASA Astrophysics Data System (ADS)

Jeschke, Christina; Knöller, Kay; Koschorreck, Matthias; Ussath, Maria; Hoth, Nils

2014-05-01

In Germany, a major share of the energy production is based on the burning of lignite from open cast pit mines. The remediation and re-cultivation of the former mining areas in the Lusatian and Central German lignite mining district is an enormous technical and economical challenge. After mine closures, the surrounding landscapes are threatened by acid mine drainage (AMD), i.e. the acidification and mineralization of rising groundwater with metals and inorganic contaminants. The high content of sulfur (sulfuric acid, sulfate), nitrogen (ammonium) and iron compounds (iron-hydroxides) deteriorates the groundwater quality and decelerates sustainable development of tourism in (former) mining landscapes. Natural biodegradation or attenuation (NA) processes of inorganic contaminants are considered to be a technically low impact and an economically beneficial solution. The investigations of the stable isotope compositions of compounds involved in NA processes helps clarify the dynamics of natural degradation and provides specific informations on retention processes of sulfate and nitrogen-compounds in mine dump water, mine dump sediment, and residual pit lakes. In an active mine dump we investigated zones where the process of bacterial sulfate reduction, as one very important NA process, takes place and how NA can be enhanced by injecting reactive substrates. Stable isotopes signatures of sulfur and nitrogen components were examined and evaluated in concert with hydrogeochemical data. In addition, we delineated the sources of ammonium pollution in mine dump sediments and investigated nitrification by 15N-labeling techniques to calculate the limit of the conversion of harmful ammonium to nitrate in residual mining lakes. Ultimately, we provided an isotope biogeochemical assessment of natural attenuation of sulfate and ammonium at mine dump sites and mining lakes. Also, we estimated the risk potential for water in different compartments of the hydrological system. In laboratory experiments, we tested reactive materials that may speed up the process of bacterial sulfate reduction. In in-situ experiments, we quantified nitrification rates. Based on the results, we are able to suggest promising technical measures that enhance natural attenuation processes at mine dump site and in mining lakes. The natural water cycle in lignite mining landscapes is heavily impacted by human activities. Basically, nature is capable of cleaning itself to a certain extent after mining activities stopped. However, it is our responsibility to support biogeochemical processes to make them more efficient and more sustainable. Isotopic monitoring proved to be an excellent tool for assessing the relevance and performance of different re-cultivation measures for a positive long-term development of the water quality in large-scale aquatic systems affected by the impact of lignite mining.

One year water chemistry monitoring of the flooding of the Meirama open pit (NW Spain)

NASA Astrophysics Data System (ADS)

Delgado, J.; Juncosa, R.; Vázquez, A.; Fernández-Bogo, S.

2009-04-01

In December, 2007, after 30 years of operations, the mine of Meirama finished the extraction of brown lignite. Starting in April 2008, the flooding of the open pit has started and this is leading to the formation of a large mining lake (~2 km2 surface and up to 180 m depth) in which surface (river and rain water) and ground waters are involved. Since the beginning of the flooding, lake waters are weekly sampled and analyzed for temperature, pH, redox, EC, TDS, TSS, DO,DIC, DOC, turbidity, alkalinity/acidity as well as nearly 40 inorganic chemical components. Stable water isotopes (deuterium and oxygen) are also being recorded. In order to better understand the dynamic chemical evolution of lake waters, the chemical characteristics of rain water as well as a series of lake tributaries and ground waters are also being measured. Since the beginning of the flooding process, the chemical quality of lake water has experienced an interesting evolution that obeys to a variety of circumstances. The silicic geologic substratum of the catchment determines that both ground and surface waters have a rather low alkalinity. Moreover, the presence of disseminated sulfides (mainly pyrite) within the schistous materials of the mine slopes and internal rock dumps provokes a significant acidic load. From April to October 2008, the lake waters had only the contribution of rain and ground waters. Since the beginning of October, a significant volume of surface waters has been derived to the mine hole. Taking pH as indicator, the first water body had a rather acidic pH (~3) which was progressively amended with the addition of a certain amount of lime to reach an upper value of ~8 by late August. The diminution in the addition of lime up to its elimination, in December, has conducted to the progressive acidification of the lake. At present, an instrumented floating deck is being deployed in the lake. This device will serve as a base point where it is planned to locate a series of instrumentation (complete weather monitoring station, multiparametric probe, sediment trap line) that will complement with depth profiles the surficial sampling performed so far.

Modelling Geomechanical Heterogeneity of Rock Masses Using Direct and Indirect Geostatistical Conditional Simulation Methods

NASA Astrophysics Data System (ADS)

Eivazy, Hesameddin; Esmaieli, Kamran; Jean, Raynald

2017-12-01

An accurate characterization and modelling of rock mass geomechanical heterogeneity can lead to more efficient mine planning and design. Using deterministic approaches and random field methods for modelling rock mass heterogeneity is known to be limited in simulating the spatial variation and spatial pattern of the geomechanical properties. Although the applications of geostatistical techniques have demonstrated improvements in modelling the heterogeneity of geomechanical properties, geostatistical estimation methods such as Kriging result in estimates of geomechanical variables that are not fully representative of field observations. This paper reports on the development of 3D models for spatial variability of rock mass geomechanical properties using geostatistical conditional simulation method based on sequential Gaussian simulation. A methodology to simulate the heterogeneity of rock mass quality based on the rock mass rating is proposed and applied to a large open-pit mine in Canada. Using geomechanical core logging data collected from the mine site, a direct and an indirect approach were used to model the spatial variability of rock mass quality. The results of the two modelling approaches were validated against collected field data. The study aims to quantify the risks of pit slope failure and provides a measure of uncertainties in spatial variability of rock mass properties in different areas of the pit.

Application of Universal Thermal Climate Index (UTCI) for assessment of occupational heat stress in open-pit mines.

PubMed

Nassiri, Parvin; Monazzam, Mohammad Reza; Golbabaei, Farideh; Dehghan, Somayeh Farhang; Rafieepour, Athena; Mortezapour, Ali Reza; Asghari, Mehdi

2017-10-07

The purpose of this article is to examine the applicability of Universal Thermal Climate Index (UTCI) index as an innovative index for evaluating of occupational heat stress in outdoor environments. 175 workers of 12 open-pit mines in Tehran, Iran were selected for this research study. First, the environmental variables such as air temperature, wet-bulb temperature, globe temperature, relative humidity and air flow rate were measured; then UTCI, wet-bulb globe temperature (WBGT) and heat stress index (HSI) indices were calculated. Simultaneously, physiological parameters including heart rate, oral temperature, tympanic temperature and skin temperature of workers were measured. UTCI and WBGT are positively significantly correlated with all environmental parameters (p<0.03), except for air velocity (r<-0.39; p>0.05). Moreover, a strong significant relationship was found between UTCI and WBGT (r=0.95; p<0.001). The significant positive correlations exist between physiological parameters including oral temperature, tympanic and skin temperatures and heart rate and both the UTCI and WBGT indices (p<0.029). The highest correlation coefficient has been found between the UTCI and physiological parameters. Due to the low humidity and air velocity (~<1 m/s) in understudied mines, UTCI index appears to be appropriate to assess the occupational heat stress in these outdoor workplaces.

Proteomics technique opens new frontiers in mobilome research

PubMed Central

Davidson, Andrew D.; Matthews, David A.

2017-01-01

ABSTRACT A large proportion of the genome of most eukaryotic organisms consists of highly repetitive mobile genetic elements. The sum of these elements is called the “mobilome,” which in eukaryotes is made up mostly of transposons. Transposable elements contribute to disease, evolution, and normal physiology by mediating genetic rearrangement, and through the “domestication” of transposon proteins for cellular functions. Although ‘omics studies of mobilome genomes and transcriptomes are common, technical challenges have hampered high-throughput global proteomics analyses of transposons. In a recent paper, we overcame these technical hurdles using a technique called “proteomics informed by transcriptomics” (PIT), and thus published the first unbiased global mobilome-derived proteome for any organism (using cell lines derived from the mosquito Aedes aegypti). In this commentary, we describe our methods in more detail, and summarise our major findings. We also use new genome sequencing data to show that, in many cases, the specific genomic element expressing a given protein can be identified using PIT. This proteomic technique therefore represents an important technological advance that will open new avenues of research into the role that proteins derived from transposons and other repetitive and sequence diverse genetic elements, such as endogenous retroviruses, play in health and disease. PMID:28932623

Environmental Improvement Of Opencast Mining

NASA Astrophysics Data System (ADS)

Prokopenko, S.; Sushko, A.; Filatov, Yu; Kislyakov, M.; Kislyakov, I.

2017-01-01

Existing classifications of waste dumps in the quarries are given and their phenomenological nature is clarified. The need to identify the essence of the term "dump" is shown as well as the idea of "dump" as an artificial formation with everted and mixed rocks distanced from the quarry. Essential classification of man-made rock formations in quarries is developed. Characteristic of variations of man-made waste formations in quarries is developed. To reduce harmful effects of open-pit mining, dumps should be substituted with strat-lays - man-made structures relevant to natural stratification of litho-substances. Construction of strat-lays would improve ecological and technological culture of open cast mining.

10 CFR 1045.15 - Classification and declassification presumptions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... criteria in § 1045.16 indicates otherwise: (1) Basic science: mathematics, chemistry, theoretical and experimental physics, engineering, materials science, biology and medicine; (2) Magnetic confinement fusion...); (5) Fact of use of safety features (e.g., insensitive high explosives, fire resistant pits) to lower...

10 CFR 1045.15 - Classification and declassification presumptions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... criteria in § 1045.16 indicates otherwise: (1) Basic science: mathematics, chemistry, theoretical and experimental physics, engineering, materials science, biology and medicine; (2) Magnetic confinement fusion...); (5) Fact of use of safety features (e.g., insensitive high explosives, fire resistant pits) to lower...

Bright Particle in Hole Dug by Scooping of Martian Soil

NASA Image and Video Library

2012-10-18

The mission science team assessed the bright particles in this scooped pit to be native Martian material rather than spacecraft debris as seen in this image from NASA Mars rover Curiosity as it collected its second scoop of Martian soil.

Complex Burial and Exhumation of South Polar Cap Pitted Terrain

NASA Technical Reports Server (NTRS)

2000-01-01

This image is illuminated by sunlight from the upper left. The two prominent bright stripes at the left/center of the image are covered with bright frost and thus create the illusion that they are sunlit from the lower left.

The large pits, troughs, and 'swiss cheese' of the south polar residual cap appear to have been formed in the upper 4 or 5 layers of the polar material. Each layer is approximately 2 meters (6.6 feet) thick. Some Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) images of this terrain show examples in which older pitted and eroded layers have been previously buried and are now being exhumed. The example shown here includes two narrow, diagonal slopes that trend from upper left toward lower right at the left/center portion of the frame. Along the bottoms of these slopes are revealed a layer that underlies them in which there are many more pits and troughs than in the upper layer. It is likely in this case that the lower layer formed its pits and troughs before it was covered by the upper layer. This observation suggests that the troughs, pits, and 'swiss cheese' features of the south polar cap are very old and form over long time scales.

The picture is located near 84.6oS, 45.1oW, and covers an area 3 km by 5 km (1.9 x 3.1 mi) at a resolution of about 3.8 meters (12 ft) per pixel. The image was taken during southern spring on August 29, 1999.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

Concentrations of Radionuclides (226Ra, 232Th, 40K, and 137Cs) in Chernozems of Volgograd Oblast Sampled in Different Years

NASA Astrophysics Data System (ADS)

Aparin, B. F.; Mingareeva, E. V.; Sanzharova, N. I.; Sukhacheva, E. Yu.

2017-12-01

Data on the concentrations of natural (226Ra, 232Th and 40K) and artificial (137Cs) radionuclides and on the physicochemical properties of chernozems sampled in different years are presented. In 1952, upon the creation of the Penza-Kamensk state shelterbelt, three deep (up to 3 m) soil pits were examined within the former arable field under two-year-old plantations of ash and maple along the transect crossing the territory of the Beloprudskaya Experimental Station of the USSR Academy of Sciences in Volgograd oblast. The samples from these pits were included into the collection of dated soil samples of the Dokuchaev Central Soil Science Museum. Five pits were examined along the same transect in 2009: three pits under shelterbelts (analogues of the pits studied in 1952) and two pits on arable fields between the shelterbelts. In the past 57 years, certain changes took place in the soil structure, bulk density, and the content and composition of humus. The salt profile of soils changed significantly under the forests. The comparison of distribution patterns of natural soil radionuclides in 1952 and 2009 demonstrated their higher contents at the depth of 10-20 cm in 2009 (except for the western shelterbelt). Background concentrations of natural radionuclides in parent materials and relationships between their distributions and the salt profiles of soils have been determined; they are most clearly observed is the soils under shelterbelts. Insignificant contamination with 137Cs (up to 34 Bq/kg) has been found in the samples of 2009 from the upper (0-20 cm) horizon. The activity of 137Cs regularly decreases from the east to the west; the highest concentrations of this radionuclide are found in the topmost 10 cm. This allows us to suppose that 137Cs was brought with aerial dust by eastern winds, and the shelterbelts served as barriers to the wind flow.

Conceptual Design Report Cask Loadout Sys and Cask Drop Redesign for the Immersion Pail Support Structure and Operator Interface Platform at 105 K West

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

LANGEVIN, A.S.

1999-07-12

This conceptual design report documents the redesign of the IPSS and the OIP in the 105 KW Basin south loadout pit due to a postulated cask drop accident, as part of Project A.5/A.6, Canister Transfer Facility Modifications. Project A.5/A.6 involves facility modifications needed to transfer fuel from the basin into the cask-MCO. The function of the IPSS is to suspend, guide, and position the immersion pail. The immersion pail protects the cask-MCO from contamination by basin water and acts as a lifting device for the cask-MCO. The OIP provides operator access to the south loadout pit. Previous analyses studied themore » effects of a cask-MCO drop on the south loadout pit concrete structure and on the IPSS. The most recent analysis considered the resulting loads at the pit slab/wall joint (Kanjilal, 1999). This area had not been modeled previously, and the analysis results indicate that the demand capacity exceeds the allowable at the slab/wall joint. The energy induced on the south loadout pit must be limited such that the safety class function of the basin is maintained. The solution presented in this CDR redesigns the IPSS and the OIP to include impact-absorbing features that will reduce the induced energy. The impact absorbing features of the new design include: Impact-absorbing material at the IPSS base and at the upper portion of the IPSS legs. A sleeve which provides a hydraulic means of absorbing energy. Designing the OIP to act as an impact absorber. The existing IPSS structure in 105 KW will be removed. This conceptual design considers only loads resulting from drops directly over the IPSS and south loadout pit area. Drops in other areas of the basin are not considered, and will be covered as part of a future revision to this CDR.« less

Nucleation sites of Ge nanoislands grown on pit-patterned Si substrate prepared by electron-beam lithography

NASA Astrophysics Data System (ADS)

Smagina, Zh. V.; Zinovyev, V. A.; Rudin, S. A.; Novikov, P. L.; Rodyakina, E. E.; Dvurechenskii, A. V.

2018-04-01

Regular pit-patterned Si(001) substrates were prepared by electron-beam lithography followed by plasma chemical etching. The geometry of the pits was controlled by varying the etching conditions and the electron-beam exposure duration. It was shown that the location of three-dimensional (3D) Ge nanoislands subsequently grown on the pit-patterned Si substrates depends on the shape of the pit bottom. In the case of pits having a sharp bottom, 3D Ge islands nucleate inside the pits. For pits with a wide flat bottom, the 3D Ge island nucleation takes place at the pit periphery. This effect is attributed to the strain relaxation depending not only on the initial pit shape, but also on its evolution during the Ge wetting layer deposition. It was shown by Monte Carlo simulations that in the case of a pit with a pointed bottom, the relaxation is most effective inside the pit, while for a pit with a wide bottom, the most relaxed area migrates during Ge deposition from the pit bottom to its edges, where 3D Ge islands nucleate.

Sesquinary reimpacts dominate surface characteristics on Phobos

NASA Astrophysics Data System (ADS)

Nayak, Michael

2018-01-01

We use topographic data to show that impact craters with pitted floor deposits are among the deepest on Mars. This is consistent with the interpretation of pitted materials as primary crater-fill impactite deposits emplaced during crater formation. Our database consists of 224 pitted material craters ranging in size from ˜1 to 150 km in diameter. Our measurements are based on topographic data from the Mars Orbiter Laser Altimeter (MOLA) and the High-Resolution Stereo Camera (HRSC). We have used these craters to measure the relationship between crater diameter and the initial post-formation depth. Depth was measured as maximum rim-to-floor depth, (dr), but we also report the depth measured using other definitions. The database was down-selected by refining or removing elevation measurements from "problematic" craters affected by processes and conditions that influenced their dr/D, such as pre-impact slopes/topography and later overprinting craters. We report a maximum (deepest) and mean scaling relationship of dr = (0.347±0.021)D0.537±0.017 and dr = (0.323±0.017)D0.538±0.016, respectively. Our results suggest that significant variations between previously-reported MOLA-based dr vs. D relationships may result from the inclusion of craters that: 1) are influenced by atypical processes (e.g., highly oblique impact), 2) are significantly degraded, 3) reside within high-strength regions, and 4) are transitional (partially collapsed). By taking such issues into consideration and only measuring craters with primary floor materials, we present the best estimate to date of a MOLA-based relationship of dr vs. D for the least-degraded complex craters on Mars. This can be applied to crater degradation studies and provides a useful constraint for models of complex crater formation.

A depth versus diameter scaling relationship for the best-preserved melt-bearing complex craters on Mars

NASA Astrophysics Data System (ADS)

Tornabene, Livio L.; Watters, Wesley A.; Osinski, Gordon R.; Boyce, Joseph M.; Harrison, Tanya N.; Ling, Victor; McEwen, Alfred S.

2018-01-01

We use topographic data to show that impact craters with pitted floor deposits are among the deepest on Mars. This is consistent with the interpretation of pitted materials as primary crater-fill impactite deposits emplaced during crater formation. Our database consists of 224 pitted material craters ranging in size from ∼1 to 150 km in diameter. Our measurements are based on topographic data from the Mars Orbiter Laser Altimeter (MOLA) and the High-Resolution Stereo Camera (HRSC). We have used these craters to measure the relationship between crater diameter and the initial post-formation depth. Depth was measured as maximum rim-to-floor depth, (dr), but we also report the depth measured using other definitions. The database was down-selected by refining or removing elevation measurements from ;problematic; craters affected by processes and conditions that influenced their dr/D, such as pre-impact slopes/topography and later overprinting craters. We report a maximum (deepest) and mean scaling relationship of dr = (0.347 ± 0.021)D0.537 ± 0.017 and dr = (0.323 ± 0.017)D0.538 ± 0.016, respectively. Our results suggest that significant variations between previously-reported MOLA-based dr vs. D relationships may result from the inclusion of craters that: 1) are influenced by atypical processes (e.g., highly oblique impact), 2) are significantly degraded, 3) reside within high-strength regions, and 4) are transitional (partially collapsed). By taking such issues into consideration and only measuring craters with primary floor materials, we present the best estimate to date of a MOLA-based relationship of dr vs. D for the least-degraded complex craters on Mars. This can be applied to crater degradation studies and provides a useful constraint for models of complex crater formation.

Arizona Copper

NASA Image and Video Library

2014-03-19

Arizona produces 60% of the total copper mined in the US; in 2007, 750,000 tons of copper came out of the state. One of the major mining districts is located about 30 km south of Tucson. Starting around 1950, open-pit mining replaced underground operations, and the ASARCO-Mission complex, Twin Buttes, and Sierrita mines became large open pit operations. Accompanying copper mineralization, silver, molybdenum, zinc, lead and gold are extracted. In addition to the pits themselves, enormous leach ponds and tailings piles surround the pits. The image was acquired May 31, 2012, covers an area of 22 by 28 km, and is located at 31.9 degrees north, 111 degrees west. With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on Terra. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate, Washington, D.C. More information about ASTER is available at asterweb.jpl.nasa.gov/ Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Martian Central Pit Craters

NASA Technical Reports Server (NTRS)

Hillman, E.; Barlow, N. G.

2005-01-01

Impact craters containing central pits are rare on the terrestrial planets but common on icy bodies. Mars is the exception among the terrestrial planets, where central pits are seen on crater floors ( floor pits ) as well as on top of central peaks ( summit pits ). Wood et al. [1] proposed that degassing of subsurface volatiles during crater formation produced central pits. Croft [2] argued instead that central pits might form during the impact of volatile-rich comets. Although central pits are seen in impact craters on icy moons such as Ganymede, they do show some significant differences from their martian counterparts: (a) only floor pits are seen on Ganymede, and (b) central pits begin to occur at crater diameters where the peak ring interior morphology begins to appear in terrestrial planet craters [3]. A study of craters containing central pits was conducted by Barlow and Bradley [4] using Viking imagery. They found that 28% of craters displaying an interior morphology on Mars contain central pits. Diameters of craters containing central pits ranged from 16 to 64 km. Barlow and Bradley noted that summit pit craters tended to be smaller than craters containing floor pits. They also noted a correlation of central pit craters with the proposed rings of large impact basins. They argued that basin ring formation fractured the martian crust and allowed subsurface volatiles to concentrate in these locations. They favored the model that degassing of the substrate during crater formation was responsible for central pit formation due to the preferential location of central pit craters along these basin rings.

The analysis of the Tectonics - SSS - Seismicity System in the 3D-model of the Rasvumchorr Mine - Central Open Pit Natural and Technical System (Khibiny)

NASA Astrophysics Data System (ADS)

Zhirov, Dmitry; Klimov, Sergey; Zhirova, Anzhela; Panteleev, Alexey; Rybin, Vadim

2017-04-01

Main hazardous factors during the operation of deposits represent tectonics (structural dislocation), strain and stress state (SSS), and seismicity. The cause and effect relationships in the Fault Tectonics - SSS - Seismicity system were analyzed using a 3D geological and structural Rasvumchorr Mine - Central Open Pit model. This natural and technical system (NTS) has resulted from the development of the world-class apatite-nepheline deposits the Apatite Circus and Rasvumchorr Plateau. The 3D model integrates various spatial data on the earth's surface topography before and after mining, geometry of mines and dumps, SSS measurements and rock pressure, seismicity, fault tectonics and etc. The analysis of the 3D model has clearly demonstrated the localization of three main seismic emanation zones in the areas of maximum anthropogenic variation of the initial rock state, and namely: ore pass zone under the Southern edge of the Central open pit, collapse and joining zone of the Rasvumchorr Mine and NW edge of the open pit, and zone under the Apatite Circus plate - collapse console. And, on the contrary, in the area of a large dump under the underground mine, a perennial seismic minimum zone was identified. The relation of the seismicity and fault tectonics was revealed only in three local sectors near come certain echelon fissures of the Main Fault(MF). No confinement of increased seismicity areas to the MF and other numerous echelon fissures is observed. The same picture occurs towards manifestations of rock pressure. Only an insignificant part of echelon fissures (including low rank of hierarchy) controls hazardous manifestations of rock pressure (dumps, strong deformations of the mine contour, etc.). It is shown that the anthropogenic factor (explosive, geometry and arrangement of mined spaces and collapse console), as well as the time factor significantly change orientation and structure (contrast and heterogeneity) of the stress fields. Time series of natural geophysical field fluctuations were additionally analyzed in order to find relationships with the seismicity. A sustainable regular relationship between the seismicity and solar and lunar tides has been observed; though, medium (classes 3 to 6) and high (class 7 and above) energy values of the events reveal various symmetry towards the Lunar cycle phases. The relationship of seismicity with other geophysical fields, e.g., geomagnetic disturbances, is defined as weak to very weak. The anthropogenic (man-induced) factor mostly influences the seismicity in the NTS rock masses. A law for shifting of maximum seismicity zones following the advance of the mining front has been found. The 3D model integrates various spatial data on the earth's surface topography before and after mining, geometry of mines and dumps, SSS measurements, and rock pressure, seismicity, fault tectonics, and other manifestations. The study is made within R&D topic No. 0231-2015-0013. The collection, processing, and analysis of data for natural stress fields became possible due to the support from RSF grant 14-17-00751.

Mapping of the minimal inorganic phosphate transporting unit of human PiT2 suggests a structure universal to PiT-related proteins from all kingdoms of life

PubMed Central

2011-01-01

Background The inorganic (Pi) phosphate transporter (PiT) family comprises known and putative Na+- or H+-dependent Pi-transporting proteins with representatives from all kingdoms. The mammalian members are placed in the outer cell membranes and suggested to supply cells with Pi to maintain house-keeping functions. Alignment of protein sequences representing PiT family members from all kingdoms reveals the presence of conserved amino acids and that bacterial phosphate permeases and putative phosphate permeases from archaea lack substantial parts of the protein sequence when compared to the mammalian PiT family members. Besides being Na+-dependent Pi (NaPi) transporters, the mammalian PiT paralogs, PiT1 and PiT2, also are receptors for gamma-retroviruses. We have here exploited the dual-function of PiT1 and PiT2 to study the structure-function relationship of PiT proteins. Results We show that the human PiT2 histidine, H502, and the human PiT1 glutamate, E70, - both conserved in eukaryotic PiT family members - are critical for Pi transport function. Noticeably, human PiT2 H502 is located in the C-terminal PiT family signature sequence, and human PiT1 E70 is located in ProDom domains characteristic for all PiT family members. A human PiT2 truncation mutant, which consists of the predicted 10 transmembrane (TM) domain backbone without a large intracellular domain (human PiT2ΔR254-V483), was found to be a fully functional Pi transporter. Further truncation of the human PiT2 protein by additional removal of two predicted TM domains together with the large intracellular domain created a mutant that resembles a bacterial phosphate permease and an archaeal putative phosphate permease. This human PiT2 truncation mutant (human PiT2ΔL183-V483) did also support Pi transport albeit at very low levels. Conclusions The results suggest that the overall structure of the Pi-transporting unit of the PiT family proteins has remained unchanged during evolution. Moreover, in combination, our studies of the gene structure of the human PiT1 and PiT2 genes (SLC20A1 and SLC20A2, respectively) and alignment of protein sequences of PiT family members from all kingdoms, along with the studies of the dual functions of the human PiT paralogs show that these proteins are excellent as models for studying the evolution of a protein's structure-function relationship. PMID:21586110

Mapping of the minimal inorganic phosphate transporting unit of human PiT2 suggests a structure universal to PiT-related proteins from all kingdoms of life.

PubMed

Bøttger, Pernille; Pedersen, Lene

2011-05-17

The inorganic (Pi) phosphate transporter (PiT) family comprises known and putative Na(+)- or H(+)-dependent Pi-transporting proteins with representatives from all kingdoms. The mammalian members are placed in the outer cell membranes and suggested to supply cells with Pi to maintain house-keeping functions. Alignment of protein sequences representing PiT family members from all kingdoms reveals the presence of conserved amino acids and that bacterial phosphate permeases and putative phosphate permeases from archaea lack substantial parts of the protein sequence when compared to the mammalian PiT family members. Besides being Na(+)-dependent P(i) (NaP(i)) transporters, the mammalian PiT paralogs, PiT1 and PiT2, also are receptors for gamma-retroviruses. We have here exploited the dual-function of PiT1 and PiT2 to study the structure-function relationship of PiT proteins. We show that the human PiT2 histidine, H(502), and the human PiT1 glutamate, E(70),--both conserved in eukaryotic PiT family members--are critical for P(i) transport function. Noticeably, human PiT2 H(502) is located in the C-terminal PiT family signature sequence, and human PiT1 E(70) is located in ProDom domains characteristic for all PiT family members.A human PiT2 truncation mutant, which consists of the predicted 10 transmembrane (TM) domain backbone without a large intracellular domain (human PiT2ΔR(254)-V(483)), was found to be a fully functional P(i) transporter. Further truncation of the human PiT2 protein by additional removal of two predicted TM domains together with the large intracellular domain created a mutant that resembles a bacterial phosphate permease and an archaeal putative phosphate permease. This human PiT2 truncation mutant (human PiT2ΔL(183)-V(483)) did also support P(i) transport albeit at very low levels. The results suggest that the overall structure of the P(i)-transporting unit of the PiT family proteins has remained unchanged during evolution. Moreover, in combination, our studies of the gene structure of the human PiT1 and PiT2 genes (SLC20A1 and SLC20A2, respectively) and alignment of protein sequences of PiT family members from all kingdoms, along with the studies of the dual functions of the human PiT paralogs show that these proteins are excellent as models for studying the evolution of a protein's structure-function relationship. © 2011 Bøttger and Pedersen; licensee BioMed Central Ltd.

ALKALI-ACTIVATED CEMENT (AAC) AS A SUSTAINABLE BUILDING MATERIAL

EPA Science Inventory

It is expected that this project will result in 1) production of technical paper(s) and presentations that better explains the relationships between chemical, microstructural, and performance properties of AACs, 2) commercially viable AAC formulae that pass the ASTM C1157 stan...

Surface modifications on toughened, fine-grained, recrystallized tungsten with repetitive ELM-like pulsed plasma irradiation

NASA Astrophysics Data System (ADS)

Kikuchi, Y.; Sakuma, I.; Kitagawa, Y.; Asai, Y.; Onishi, K.; Fukumoto, N.; Nagata, M.; Ueda, Y.; Kurishita, H.

2015-08-01

Surface modifications of toughened, fine-grained, recrystallized tungsten (TFGR W) materials with 1.1 wt.% TiC and 3.3 wt.% TaC dispersoids due to repetitive ELM-like pulsed (∼0.15 ms) helium plasma irradiation have been investigated by using a magnetized coaxial plasma gun. No surface cracking at the center part of the TFGR W samples exposed to 20 plasma pulses of ∼0.3 MJ m-2 was observed. The suppression of surface crack formation due to the increase of the grain boundary strength by addition of TiC and TaC dispersoids was confirmed in comparison with a pure W material. On the other hand, surface cracks and small pits appeared at the edge part of the TFGR W sample after the pulsed plasma irradiation. Erosion of the TiC and TaC dispersoids due to the pulsed plasma irradiation could cause the small pits on the surface, resulting in the surface crack formation.

Corrosion of copper and authigenic sulfide mineral growth in hydrothermal bentonite experiments

NASA Astrophysics Data System (ADS)

Caporuscio, F. A.; Palaich, S. E. M.; Cheshire, M. C.; Jové Colón, C. F.

2017-03-01

The focus of this experimental work is to characterize interaction of bentonite with possible used-fuel waste container materials. Experiments were performed up to 300 °C at 150-160 bars for five to six weeks. Bentonite was saturated with a 1900 ppm K-Ca-Na-Cl-bearing water with Cu-foils. Copper rapidly degrades into chalcocite (CuS2) and minor covellite (CuS) in the presence of H2S. Chalcocite growth and corrosion pit depths were measured for four different experimental runs yielding corrosion rates between 8.8 and 116 μm/yr depending on duration of experiment, brine composition, and clay type (bentonite vs. Opalinus Clay). Results of this research show that although pit-corrosion is demonstrated on Cu substrates, experiments show that the reactions that ensue, and the formation of minerals that develop, are extraordinarily slow. This supports the use of Cu in nuclide-containment systems as a possible engineered barrier system material.

Corrosion of copper and authigenic sulfide mineral growth in hydrothermal bentonite experiments

DOE PAGES

Caporuscio, F. A.; Palaich, Sarah E. M.; Cheshire, M. C.; ...

2016-12-29

The focus of this experimental paper is to characterize interaction of bentonite with possible used-fuel waste container materials. Experiments were performed up to 300 °C at 150–160 bars for five to six weeks. Bentonite was saturated with a 1900 ppm K-Ca-Na-Cl-bearing water with Cu-foils. Copper rapidly degrades into chalcocite (CuS 2) and minor covellite (CuS) in the presence of H 2S. Chalcocite growth and corrosion pit depths were measured for four different experimental runs yielding corrosion rates between 8.8 and 116 μm/yr depending on duration of experiment, brine composition, and clay type (bentonite vs. Opalinus Clay). Results of this researchmore » show that although pit-corrosion is demonstrated on Cu substrates, experiments show that the reactions that ensue, and the formation of minerals that develop, are extraordinarily slow. Finally, this supports the use of Cu in nuclide-containment systems as a possible engineered barrier system material.« less

Time indices of multiphasic development in genotypes of sweet cherry are similar from dormancy to cessation of pit growth.

PubMed

Gibeaut, David M; Whiting, Matthew D; Einhorn, Todd

2017-02-01

The archetypical double sigmoid-shaped growth curve of the sweet cherry drupe (Prunus avium) does not address critical development from eco-dormancy to anthesis and has not been correlated to reproductive bud development. Accurate representation of the growth and development of post-anthesis ovaries is confounded by anthesis timing, fruiting-density and the presence of unfertilized and defective ovaries whose growth differs from those that persist to maturation. These factors were addressed to assess pre-anthesis and full-season growth and development of three sweet cherry cultivars, 'Chelan', 'Bing' and 'Sweetheart', differing primarily in seasonal duration and fruit size. Volume was calculated from photographic measurements of reproductive buds, ovaries and pits at all phases of development. A population of unfertilized ovaries was produced using bee-exclusion netting to enable a statistical comparison with an open pollinated population to detect differences in size and shape between successful and failing fruit growth. Anthesis timing and fruiting-density were manipulated by floral extinction at the spur and whole-tree scales. Developmental time indices were analysed using polynomial curve fitting of log-transformed data supported by Richards and logistic functions of asymptotic growth of the pit and maturing fruit, respectively. Pre-anthesis growth began at the completion of eco-dormancy. A slight decline in relative growth rate (RGR) was observed during bud scale separation approx. -16 d from anthesis (DFA) before resumption of exponential growth to a maximum about 14 DFA. After anthesis, reduced growth of unfertilized or defective ovaries was partly discriminated from successful fruit at 5 DFA and completely at 25 DFA. Time indices of RGR inflections were similar among cultivars when adjusted for anthesis date alone, until the end of pit growth. Asymptotic growth of the pit underpinned the declining growth rate of fruit at the end of the first exponential growth phase. Duration of the subsequent expansive growth phase accounted for genotypic differences in seasonal duration and final size. Pit size and final fruit size were inversely related to fruiting-density. Developmental differences among early, mid and late maturing cultivars were not detected until the final growth period. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Time indices of multiphasic development in genotypes of sweet cherry are similar from dormancy to cessation of pit growth

PubMed Central

Gibeaut, David M.; Whiting, Matthew D.; Einhorn, Todd

2017-01-01

Background and Aims The archetypical double sigmoid-shaped growth curve of the sweet cherry drupe (Prunus avium) does not address critical development from eco-dormancy to anthesis and has not been correlated to reproductive bud development. Accurate representation of the growth and development of post-anthesis ovaries is confounded by anthesis timing, fruiting-density and the presence of unfertilized and defective ovaries whose growth differs from those that persist to maturation. These factors were addressed to assess pre-anthesis and full-season growth and development of three sweet cherry cultivars, ‘Chelan’, ‘Bing’ and ‘Sweetheart’, differing primarily in seasonal duration and fruit size. Methods Volume was calculated from photographic measurements of reproductive buds, ovaries and pits at all phases of development. A population of unfertilized ovaries was produced using bee-exclusion netting to enable a statistical comparison with an open pollinated population to detect differences in size and shape between successful and failing fruit growth. Anthesis timing and fruiting-density were manipulated by floral extinction at the spur and whole-tree scales. Developmental time indices were analysed using polynomial curve fitting of log-transformed data supported by Richards and logistic functions of asymptotic growth of the pit and maturing fruit, respectively. Key Results Pre-anthesis growth began at the completion of eco-dormancy. A slight decline in relative growth rate (RGR) was observed during bud scale separation approx. −16 d from anthesis (DFA) before resumption of exponential growth to a maximum about 14 DFA. After anthesis, reduced growth of unfertilized or defective ovaries was partly discriminated from successful fruit at 5 DFA and completely at 25 DFA. Time indices of RGR inflections were similar among cultivars when adjusted for anthesis date alone, until the end of pit growth. Asymptotic growth of the pit underpinned the declining growth rate of fruit at the end of the first exponential growth phase. Duration of the subsequent expansive growth phase accounted for genotypic differences in seasonal duration and final size. Pit size and final fruit size were inversely related to fruiting-density. Conclusions Developmental differences among early, mid and late maturing cultivars were not detected until the final growth period. PMID:28064193

Musculoskeletal symptoms and exposure to whole-body vibration among open-pit mine workers in the Arctic.

PubMed

Burström, Lage; Aminoff, Anna; Björ, Bodil; Mänttäri, Satu; Nilsson, Tohr; Pettersson, Hans; Rintamäki, Hannu; Rödin, Ingemar; Shilov, Victor; Talykova, Ljudmila; Vaktskjold, Arild; Wahlström, Jens

2017-06-19

This cross-sectional questionnaire study was carried out at 4 open-pit mines in Finland, Norway, Russia and Sweden as part of the MineHealth project. The aim has been to compare the prevalence of musculoskeletal symptoms between drivers of mining vehicles and non-drivers. The mine workers were asked whether they had suffered from any musculoskeletal symptoms during the previous 12 months in specified body regions, and to grade the severity of these symptoms during the past month. They were also asked about their daily driving of mining vehicles. The questionnaire was completed by 1323 workers (757 vehicle drivers) and the reported prevalence and severity of symptoms were highest for the lower back, followed by pain in the neck, shoulder and upper back. Drivers in the Nordic mines reported fewer symptoms than non-drivers, while for Russian mine workers the results were the opposite of that. The daily driving of mining vehicles had no significant association with the risk of symptoms. Female drivers indicated a higher prevalence of symptoms as compared to male drivers. The study provided only weak support for the hypothesis that drivers of vehicles reported a higher prevalence of musculoskeletal symptoms than non-vehicle drivers. There were marked differences in the prevalence of symptoms among workers in various enterprises, even though the nature of the job tasks was similar. Int J Occup Med Environ Health 2017;30(4):553-564. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Assessment of Rock Slope Stability in Limestone Quarries in the Tournai's Region (Belgium) Using Structural Data

NASA Astrophysics Data System (ADS)

Tshibangu, Jean-Pierre; Deloge, K. Pierre-Alexandre; Deschamps, Benoît; Coudyzer, Christophe

The Tournais region is characterised by famous outcrops of carboniferous limestone which is mined out for cement and raw material production. The four main quarries found in the Region, i.e. Gaurain-Ramecroix, Milieu, Antoing and Lemay; are owned by the three main cement producers in Belgium: Italcimenti, Holcim and CBR. The global production of limestone is about 20 millions tons per year, giving big pits with depths up to 150 m. With the growth of the pits, the quarries are approaching each other leading to the problem of managing the reserves contained in the separating walls and their mechanical stability. The limestone deposit is composed of different seams having varying thickness, chemical com- position and even mechanical properties. The deposit has an overall horizontal dip and is intersected by two main sets of discontinuities with a spacing of about 10 m or less. It is also crossed by a set of east to west faults but the quarries are implanted in the in between areas, so to not be crossed by these faults. The layers and specially the shallow ones are characterised by a typical karstic weathering giving open or filled cavities. This paper presents the global work quarried out in order to study the stability of the Lemays quarry. First a description of the orientation and spacing of discontinuities is presented, and an attempt made to correlate to the development of weathering. Mechanical laboratory tests have been performed and a qualification of the rock mass assessed. A coupled approach is then presented using a mining planning analysis and mechanical simulation (i.e. Finite Element method).

The three principles of action: a Pavlovian-instrumental transfer hypothesis

PubMed Central

Cartoni, Emilio; Puglisi-Allegra, Stefano; Baldassarre, Gianluca

2013-01-01

Pavlovian conditioned stimuli can influence instrumental responding, an effect called Pavlovian-instrumental transfer (PIT). During the last decade, PIT has been subdivided into two types: specific PIT and general PIT, each having its own neural substrates. Specific PIT happens when a conditioned stimulus (CS) associated with a reward enhances an instrumental response directed to the same reward. Under general PIT, instead, the CS enhances a response directed to a different reward. While important progress has been made into identifying the neural substrates, the function of specific and general PIT and how they interact with instrumental responses are still not clear. In the experimental paradigm that distinguishes specific and general PIT an effect of PIT inhibition has also been observed and is waiting for an explanation. Here we propose an hypothesis that links these three PIT effects (specific PIT, general PIT and PIT inhibition) to three aspects of action evaluation. These three aspects, which we call “principles of action”, are: context, efficacy, and utility. In goal-directed behavior, an agent has to evaluate if the context is suitable to accomplish the goal, the efficacy of his action in getting the goal, and the utility of the goal itself: we suggest that each of the three PIT effects is related to one of these aspects of action evaluation. In particular, we link specific PIT with the estimation of efficacy, general PIT with the evaluation of utility, and PIT inhibition with the adequacy of context. We also provide a latent cause Bayesian computational model that exemplifies this hypothesis. This hypothesis and the model provide a new framework and new predictions to advance knowledge about PIT functioning and its role in animal adaptation. PMID:24312025

A probability distribution model of tooth pits for evaluating time-varying mesh stiffness of pitting gears

NASA Astrophysics Data System (ADS)

Lei, Yaguo; Liu, Zongyao; Wang, Delong; Yang, Xiao; Liu, Huan; Lin, Jing

2018-06-01

Tooth damage often causes a reduction in gear mesh stiffness. Thus time-varying mesh stiffness (TVMS) can be treated as an indication of gear health conditions. This study is devoted to investigating the mesh stiffness variations of a pair of external spur gears with tooth pitting, and proposes a new model for describing tooth pitting based on probability distribution. In the model, considering the appearance and development process of tooth pitting, we model the pitting on the surface of spur gear teeth as a series of pits with a uniform distribution in the direction of tooth width and a normal distribution in the direction of tooth height, respectively. In addition, four pitting degrees, from no pitting to severe pitting, are modeled. Finally, influences of tooth pitting on TVMS are analyzed in details and the proposed model is validated by comparing with a finite element model. The comparison results show that the proposed model is effective for the TVMS evaluations of pitting gears.

Subtypes of the Type II Pit Pattern Reflect Distinct Molecular Subclasses in the Serrated Neoplastic Pathway.

PubMed

Aoki, Hironori; Yamamoto, Eiichiro; Yamano, Hiro-O; Sugai, Tamotsu; Kimura, Tomoaki; Tanaka, Yoshihito; Matsushita, Hiro-O; Yoshikawa, Kenjiro; Takagi, Ryo; Harada, Eiji; Nakaoka, Michiko; Yoshida, Yuko; Harada, Taku; Sudo, Gota; Eizuka, Makoto; Yorozu, Akira; Kitajima, Hiroshi; Niinuma, Takeshi; Kai, Masahiro; Nojima, Masanori; Suzuki, Hiromu; Nakase, Hiroshi

2018-03-15

Colorectal serrated lesions (SLs) are important premalignant lesions whose clinical and biological features are not fully understood. We aimed to establish accurate colonoscopic diagnosis and treatment of SLs through evaluation of associations among the morphological, pathological, and molecular characteristics of SLs. A total of 388 premalignant and 18 malignant colorectal lesions were studied. Using magnifying colonoscopy, microsurface structures were assessed based on Kudo's pit pattern classification system, and the Type II pit pattern was subcategorized into classical Type II, Type II-Open (Type II-O) and Type II-Long (Type II-L). BRAF/KRAS mutations and DNA methylation of CpG island methylator phenotype (CIMP) markers (MINT1, - 2, - 12, - 31, p16, and MLH1) were analyzed through pyrosequencing. Type II-O was tightly associated with sessile serrated adenoma/polyps (SSA/Ps) with BRAF mutation and CIMP-high. Most lesions with simple Type II or Type II-L were hyperplastic polyps, while mixtures of Type II or Type II-L plus more advanced pit patterns (III/IV) were characteristic of traditional serrated adenomas (TSAs). Type II-positive TSAs frequently exhibited BRAF mutation and CIMP-low, while Type II-L-positive TSAs were tightly associated with KRAS mutation and CIMP-low. Analysis of lesions containing both premalignant and cancerous components suggested Type II-L-positive TSAs may develop into KRAS-mutated/CIMP-low/microsatellite stable cancers, while Type II-O-positive SSA/Ps develop into BRAF-mutated/CIMP-high/microsatellite unstable cancers. These results suggest that Type II subtypes reflect distinct molecular subclasses in the serrated neoplasia pathway and that they could be useful hallmarks for identifying SLs at high risk of developing into CRC.

The Role of Economic Uncertainty on the Block Economic Value - a New Valuation Approach / Rola Czynnika Niepewności Przy Obliczaniu Wskaźnika Rentowności - Nowe Podejście

NASA Astrophysics Data System (ADS)

Dehghani, H.; Ataee-Pour, M.

2012-12-01

The block economic value (EV) is one of the most important parameters in mine evaluation. This parameter can affect significant factors such as mining sequence, final pit limit and net present value. Nowadays, the aim of open pit mine planning is to define optimum pit limits and an optimum life of mine production scheduling that maximizes the pit value under some technical and operational constraints. Therefore, it is necessary to calculate the block economic value at the first stage of the mine planning process, correctly. Unrealistic block economic value estimation may cause the mining project managers to make the wrong decision and thus may impose inexpiable losses to the project. The effective parameters such as metal price, operating cost, grade and so forth are always assumed certain in the conventional methods of EV calculation. While, obviously, these parameters have uncertain nature. Therefore, usually, the conventional methods results are far from reality. In order to solve this problem, a new technique is used base on an invented binomial tree which is developed in this research. This method can calculate the EV and project PV under economic uncertainty. In this paper, the EV and project PV were initially determined using Whittle formula based on certain economic parameters and a multivariate binomial tree based on the economic uncertainties such as the metal price and cost uncertainties. Finally the results were compared. It is concluded that applying the metal price and cost uncertainties causes the calculated block economic value and net present value to be more realistic than certain conditions.

Electrochemical stability and corrosion resistance of Ti-Mo alloys for biomedical applications.

PubMed

Oliveira, N T C; Guastaldi, A C

2009-01-01

Electrochemical behavior of pure Ti and Ti-Mo alloys (6-20wt.% Mo) was investigated as a function of immersion time in electrolyte simulating physiological media. Open-circuit potential values indicated that all Ti-Mo alloys studied and pure Ti undergo spontaneous passivation due to spontaneously formed oxide film passivating the metallic surface, in the chloride-containing solution. It also indicated that the addition of Mo to pure Ti up to 15wt.% seems to improve the protection characteristics of its spontaneous oxides. Electrochemical impedance spectroscopy (EIS) studies showed high impedance values for all samples, increasing with immersion time, indicating an improvement in corrosion resistance of the spontaneous oxide film. The fit obtained suggests a single passive film present on the metals' surface, improving their resistance with immersion time, presenting the highest values to Ti-15Mo alloy. Potentiodynamic polarization showed a typical valve-metal behavior, with anodic formation of barrier-type oxide films, without pitting corrosion, even in chloride-containing solution. In all cases, the passive current values were quite small, and decrease after 360h of immersion. All these electrochemical results suggest that the Ti-15Mo alloy is a promising material for orthopedic devices, since electrochemical stability is directly associated with biocompatibility and is a necessary condition for applying a material as biomaterial.

How do titanium and Ti6Al4V corrode in fluoridated medium as found in the oral cavity? An in vitro study.

PubMed

Souza, Júlio C M; Barbosa, Sandra L; Ariza, Edith A; Henriques, Mariana; Teughels, Wim; Ponthiaux, Pierre; Celis, Jean-Pierre; Rocha, Luis A

2015-02-01

The purpose of this work was to evaluate the corrosion of commercially pure (CP) titanium and Ti6Al4V in vitro at different F(-) concentrations regularly found in the oral cavity by using different electrochemical tests and surface analysis techniques. electrochemical impedance spectroscopy (EIS), open circuit potential (OCP) and potentiodynamic polarization tests were associated to advanced characterization techniques such as SEM, EDS, AFM, ICP-MS and XPS. OCP tests revealed a higher reactivity of both CP titanium and Ti6Al4V at 12,300 ppm F(-) concentration than that recorded at 227 ppm F(-). Also, a significant decrease of the corrosion resistance of both materials was noticed by EIS in fluoride solutions. Material loss caused by corrosion was noticed on titanium surfaces by SEM and AFM in the presence of high F(-) concentration. CP titanium degraded by pitting corrosion while Ti6Al4V suffered from general corrosion showing micro-cracks on surface. Furthermore, a high release of metallic ions from the test samples after immersion at high F(-) concentrations was detected by ICP-MS, that can be potentially toxic to oral tissues. Copyright © 2014 Elsevier B.V. All rights reserved.

Evidence for and implications of sedimentary diapirism and mud volcanism in the southern Utopia highland-lowland boundary plain, Mars

USGS Publications Warehouse

Skinner, J.A.; Tanaka, K.L.

2007-01-01

Several types of spatially associated landforms in the southern Utopia Planitia highland-lowland boundary (HLB) plain appear to have resulted from localized geologic activity, including (1) fractured rises, (2) elliptical mounds, (3) pitted cones with emanating lobate materials, and (4) isolated and coalesced cavi (depressions). Stratigraphic analysis indicates these features are Hesperian or younger and may be associated with resurfacing that preferentially destroyed smaller (< 8 ?? km diameter) impact craters. Based on landform geomorphologies and spatial distributions, the documented features do not appear to be specifically related to igneous or periglacial processes or the back-wasting and erosion of the HLB scarp. We propose that these features are genetically related to and formed by sedimentary (mud) diapirs that ascended from zones of regionally confined, poorly consolidated, and mechanically weak material. We note morphologic similarities between the mounds and pitted cones of the southern Utopia boundary plain and terrestrial mud volcanoes in the Absheron Peninsula, Azerbaijan. These analogs provide a context for understanding the geological environments and processes that supported mud diapir-related modification of the HLB. In southern Utopia, mud diapirs near the Elysium volcanic edifice may have resulted in laccolith-like intrusions that produced the fractured rises, while in the central boundary plain mud diapirs could have extruded to form pitted cones, mounds, and lobate flows, perhaps related to compressional stresses that account for wrinkle ridges. The removal of material a few kilometers deep by diapiric processes may have resulted in subsidence and deformation of surface materials to form widespread cavi. Collectively, these inferences suggest that sedimentary diapirism and mud volcanism as well as related surface deformations could have been the dominant Hesperian mechanisms that altered the regional boundary plain. We discuss a model in which detritus would have accumulated thickly in the annular spaces between impact-generated structural rings of Utopia basin. We envision that these materials, and perhaps buried ejecta of Utopia basin, contained volatile-rich, low-density material that could provide the source material for the postulated sedimentary diapirs. Thick, water-rich, low-density sediments buried elsewhere along the HLB and within the lowland plains may account for similar landforms and resurfacing histories. ?? 2006 Elsevier Inc. All rights reserved.

Lake Superior, Duluth, MN

NASA Technical Reports Server (NTRS)

1973-01-01

This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo.

Research into robotic automation of drilling equipment by the Institute of Mining, UB RAS

NASA Astrophysics Data System (ADS)

Regotunov, AS; Sukhov, RI

2018-03-01

The article discusses the issues connected with the development of instrumentation for the express-determination of strength characteristics of rocks during blasthole drilling in open pit mines. The trial results of the instrumentation are reported in terms of the drilling rate–energy content interrelation determined in the analyses of experimental drilling block data and by the digital model of rock distribution in depth versus drilling complexity index.

Modern methods of surveyor observations in opencast mining under complex hydrogeological conditions.

NASA Astrophysics Data System (ADS)

Usoltseva, L. A.; Lushpei, V. P.; Mursin, VA

2017-10-01

The article considers the possibility of linking the modern methods of surveying security of open mining works to improve industrial safety in the Primorsky Territory, as well as their use in the educational process. Industrial Safety in the management of Surface Mining depends largely on the applied assessment methods and methods of stability of pit walls and slopes of dumps in the complex mining and hydro-geological conditions.

Surface Analytical Techniques for Microbiologically Influenced Corrosion. A Review

DTIC Science & Technology

1994-01-01

chemical process, oil and gas. and power generation industries and the U.S. pitting of stainle steels is 1h military have acknowledged the occurrence...ony on metal surface. photosynthetic biofilm may influence ennoblement of the open circuit potential of type 316L stainless steel so that it approaches...at depths within an estuarine biofilm on type 304 stainless steel . fur-oxidizing. iron-red ing. sulfate- -producing, and hydr en-producing b

NIR detection of pits and pit fragments in fresh cherries (abstract)

USDA-ARS?s Scientific Manuscript database

The feasibility of using near infrared (NIR) diffuse reflectance spectroscopy for the detection of pits and pit fragments in cherries was demonstrated. For detection of whole pits, 300 cherries were obtained locally and pits were removed from half. NIR reflectance spectra were obtained in triplicate...