Visualization of the structural changes in plywood and gypsum board during the growth of Chaetomium globosum and Stachybotrys chartarum.

PubMed

Lewinska, Anna M; Hoof, Jakob B; Peuhkuri, Ruut H; Rode, Carsten; Lilje, Osu; Foley, Matthew; Trimby, Patrick; Andersen, Birgitte

2016-10-01

Fungal growth in indoor environments is associated with many negative health effects. Many studies focus on brown- and white-rot fungi and their effect on wood, but there is none that reveals the influence of soft-rot fungi, such as Stachybotrys spp. and Chaetomium spp., on the structure of building materials such as plywood and gypsum wallboard. This study focuses on using micro-computed tomography (microCT) to investigate changes of the structure of plywood and gypsum wallboard during fungal degradation by S. chartarum and C. globosum. Changes in the materials as a result of dampness and fungal growth were determined by measuring porosity and pore shape via microCT. The results show that the composition of the building material influenced the level of penetration by fungi as shown by scanning electron microscopy (SEM). Plywood appeared to be the most affected, with the penetration of moisture and fungi throughout the whole thickness of the sample. Conversely, fungi grew only on the top cardboard in the gypsum wallboard and they did not have significant influence on the gypsum wallboard structure. The majority of the observed changes in gypsum wallboard occurred due to moisture. This paper suggests that the mycelium distribution within building materials and the structural changes, caused by dampness and fungal growth, depend on the type of the material. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface denudation rate of gypsum in Sicily

NASA Astrophysics Data System (ADS)

Madonia, Giuliana; Vattano, Marco; Di Maggio, Cipriano; De Waele, Jo

2016-04-01

Studies on surface denudation rate of karst rocks were carried out for many years with different methods, although researches on limestones are much more numerous than those on gypsum. In Sicily the most large and complete Messinian evaporite succession of Gruppo Gessoso - Solfifero outcrops and since 1993-1994 surface denudation measurements were performed on different types of gypsum by the Micro-Erosion Meter (M.E.M.) method. MEM stations were placed on natural sites representing different lithological features of gypsum outcrops of the Island: 1) selenite gypsum with centimetre-sized crystals; 2) selenite gypsum with sub-centimetre crystals; 3) gypsum arenite; 4) microcrystalline gypsum; and 5) gypsum laminite (balatino type). The measuring stations are positioned in three localities in western and central Sicily: Santa Ninfa (Trapani), Ciminna (Palermo) and Campofranco (Caltanissetta). The average lowering rates vary in the different lithofacies: from 0.25 mm yr-1 in microcrystalline gypsum to 0.74 mm yr-1 in selenite gypsum with centimetre-sized crystals. The average surface denudation rates are 0.40 mm yr-1 in balatino gypsum and gypsum arenite, and 0.37 mm yr-1 in selenite gypsum with sub-centimetre crystals. These different values are connected to several factors such as: rock texture, dip of gypsum surfaces, climatic conditions, troubles on the measurement sites (e.g.: presence of lichens, soil, remains of vegetation, etc.). The aim of this paper is to show the results of roughly twenty years of experimental measurements, and to compare the surface denudation rate of gypsum in Sicily with those of other evaporite areas characterised by different climatic settings.

Growth of indoor fungi on gypsum.

PubMed

Segers, F J J; van Laarhoven, K A; Wösten, H A B; Dijksterhuis, J

2017-08-01

To have a better understanding of fungal growth on gypsum building materials to prevent indoor fungal growth. Gypsum is acquired by mining or as a by-product of flue-gas desulphurization or treatment of phosphate ore for the production of fertilizer. Natural gypsum, flue-gas gypsum and phosphogypsum therefore have different mineral compositions. Here, growth of fungi on these types of gypsum was assessed. Conidia of the indoor fungi Aspergillus niger, Cladosporium halotolerans and Penicillium rubens were inoculated and observed using microscopic techniques including low-temperature scanning electron microscopy. Elemental analysis of gypsum was done using inductively coupled plasma atomic emission spectroscopy and segmented flow analysis. Moisture content of the gypsum was determined using a dynamic vapour sorption apparatus. Aspergillus niger, C. halotolerans and P. rubens hardly germinated on natural gypsum and flue-gas gypsum. The latter two fungi did show germination, outgrowth, and conidiation on phosphogypsum, while A. niger hardly germinated on this substrate. Other experiments show that C. halotolerans and P. rubens can develop in pure water, but A. niger does not. The observations show that the lack of germination of three indoor fungi is explained by the low amount of phosphor in natural, flue-gas and laboratory-grade gypsum. Additionally, C. halotolerans and P. rubens can develop in pure water, while conidia of A. niger do not show any germination, which is explained by the need for organic molecules of this species to induce germination. Indoor fungal growth is a potential threat to human health and causes damage to building materials. This study possibly helps in the application of the right type of gypsum in buildings. © 2017 The Society for Applied Microbiology.

Radium-226 content of agricultural gypsums

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

Lindeken, C.L.; Coles, D.G.

1977-01-01

Gypsum (CaSO/sub 4/ . 2H/sub 2/O), used as a soil amendment for saline-alkali soils, is obtained either by quarrying or as a by-product in the phosphate fertilizer industry. The latter, termed phospho gypsum, contains variable amounts of /sup 226/Ra, depending on the uranium content of the phosphate rock. Radium-226 contents of both quarried and phospho gypsum were determined by gamma counting in a low-background Ge(Li) spectrometer equipped with Compton suppression. Quarried samples from Nova Scotia, Iowa, Texas, and California were compared with phospho gypsum derived from Florida land pebble phosphates. Quarried gypsums showed an average radium content of 0.21 pCi/g.more » The average radium in phospho gypsum was 14.6 pCi/g. Uranium-238 measurements showed that near secular equilibrium existed between the uranium and radium in the quarried samples. Disequilibrium in the phospho gypsums occurred because of the preferential separation of radium during chemical processing. At the levels observed, no health hazard is implied from uptake of radium by plants grown in phospho gypsum treated soil.« less

The future of FGD gypsum

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

Miller, E.C.

2005-09-30

According to ACAA's 'Coal combustion production and user survey' covering 2003, FGD gypsum utilization in the USA has risen to 70% but with 12 m tons being produced annually there is great opportunity to expand its use in producing wallboard (its primary use) and also in cement and concrete products and agriculture. In 2003 less than 1 mt of FGD gypsum was sold into these latter markets. Although nearly all the 12 newest wallboard plants announced since 1995 have been designed to use this material, only 27% of total gypsum wallboard production in the USA utilizes FGD gypsum. 1 ref.,more » 2 figs., 2 photos.« less

Unravelling the mechanisms for plant survival on gypsum soils: an analysis of the chemical composition of gypsum plants from Turkey.

PubMed

Bolukbasi, A; Kurt, L; Palacio, S

2016-03-01

Depending on their specificity to gypsum, plants can be classified as gypsophiles (gypsum exclusive) and gypsovags (non-exclusive). The former may further be segregated into wide and narrow gypsophiles, depending on the breadth of their distribution area. Narrow gypsum endemics have a putative similar chemical composition to plants non-exclusive to gypsum (i.e. gypsovags), which may indicate their similar ecological strategy as stress-tolerant plant refugees on gypsum. However, this hypothesis awaits testing in different regions of the world. We compared the chemical composition of four narrow gypsum endemics, one widely distributed gypsophile and six gypsovags from Turkey. Further, we explored the plasticity in chemical composition of Turkish gypsovags growing on high- and low-gypsum content soils. Differences were explored with multivariate analyses (RDA) and mixed models (REML). Narrow gypsum endemics segregated from gypsovags in their chemical composition according to RDAs (mainly due to higher K and ash content in the former). Nevertheless, differences were small and disappeared when different nutrients were analysed individually. All the gypsovags studied accumulated more S and ash when growing on high-gypsum than on low-gypsum soils. Similar to narrow gypsum endemics from other regions of the world, most local gypsum endemics from Turkey show a similar chemical composition to gypsovags. This may indicate a shared ecological strategy as stress-tolerant plants not specifically adapted to gypsum. Nevertheless, the narrow gypsum endemic Gypsophila parva showed a chemical composition typical of gypsum specialists, indicating that various strategies are feasible within narrowly distributed gypsophiles. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

Fate of Mercury in Synthetic Gypsum Used for Wallboard Production

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

Jessica Sanderson

2007-12-31

additional coal type. In the project, process stacks in the wallboard plant were sampled using the Ontario Hydro method. In every task, the stack locations sampled included a gypsum dryer and a gypsum calciner. In Tasks 1 and 4 through 7, the stack of the dryer for the wet wallboard product was also tested. Also at each site, in-stream process samples were collected and analyzed for mercury concentration before and after each significant step in wallboard production. These results and process data were used to construct mercury mass balances across the wallboard plants. The results from the project showed a wide range of percentage mercury losses from the synthetic gypsum feedstocks as measured by the Ontario Hydro method at the process stacks, ranging from 2% to 55% of the mercury in the gypsum feedstock. For the tasks exceeding 10% mercury loss across the wallboard plant, most of the loss occurred across the gypsum calciner. When total wallboard emissions remained below 10%, the primary emission location varied with a much less pronounced difference in emission between the gypsum dryer, calciner and board dryer. For all seven tasks, the majority of the mercury emissions were measured to be in the elemental form (Hg{sup 0}). Overall, the measured mercury loss mass rates ranged from 0.01 to 0.17 grams of mercury per dry ton of synthetic gypsum processed, or 0.01 to 0.4 pounds of mercury released per million square feet of wallboard produced from synthetic gypsum. The Coal Combustion Product Production and Use Survey from the American Coal Ash Association (ACAA) indicate that 7,579,187 short tons of synthetic gypsum were used for wallboard production in 2006. Extrapolating the results of this study to the ACAA industry usage rate, we estimate that mercury releases from wallboard production plants in 2006 ranged between 150 to 3000 pounds for the entire U.S. wallboard industry. With only seven sets of wallboard plant measurements, it is difficult to draw firm conclusions about

Operator Exposure to Hydrogen Sulfide from Dairy Manure Storages Containing Gypsum Bedding.

PubMed

Fabian-Wheeler, Eileen E; Hile, Michael L; Murphy, Dennis J; Hill, Davis E; Meinen, Robert; Brandt, Robin C; Elliott, Hershel A; Hofstetter, Daniel

2017-01-26

Dairy manure storages containing gypsum-based bedding have been linked anecdotally with injury and death due to presumed dangerous levels of gases released. Recycled gypsum products are used as a cost-effective bedding alternative to improve animal welfare and provide agronomic benefits to manure recycled back to the land. Sulfur contained in gypsum (calcium sulfate) can contribute to hydrogen sulfide (H2S) gas formation under the anaerobic storage conditions typical of dairy manure slurry. Disturbance of stored manure during agitation releases a burst of volatile gases. On-farm monitoring was conducted to document conditions during manure storage agitation relative to gas concentration and operator safety. One objective was to document operator exposure to H2S levels; therefore, each operator wore a personal gas monitor while performing tasks associated with manure storage agitation. Data from three dairy bedding management categories on ten farms were compared: (1) traditional organic bedding, (2) gypsum bedding, and (3) gypsum bedding plus a manure additive thought to reduce H2S formation and/or release. Portable meters placed around the perimeter of dairy manure storages recorded H2S concentrations prior to and during 19 agitation events. Results show that farms using gypsum bedding produced higher H2S concentrations during manure storage agitation than farms using traditional bedding. In most cases, gypsum-containing manure storages produced H2S levels above recognized safe thresholds for both livestock and humans. Farm operators were most at risk during activities in close proximity to the manure storage during agitation, and conditions 10 m away from the storage were above the 20 ppm H2S threshold on some farms using gypsum bedding. Although H2S concentrations rose to dangerous levels, only two of 18 operators were exposed to >50 ppm H2S during the first 60 min of manure storage agitation. Operators who are aware of the risk of high H2S concentrations near

Consolidation of archaeological gypsum plaster by bacterial biomineralization of calcium carbonate.

PubMed

Jroundi, Fadwa; Gonzalez-Muñoz, Maria Teresa; Garcia-Bueno, Ana; Rodriguez-Navarro, Carlos

2014-09-01

Gypsum plasterworks and decorative surfaces are easily degraded, especially when exposed to humidity, and thus they require protection and/or consolidation. However, the conservation of historical gypsum-based structural and decorative materials by conventional organic and inorganic consolidants shows limited efficacy. Here, a new method based on the bioconsolidation capacity of carbonatogenic bacteria inhabiting the material was assayed on historical gypsum plasters and compared with conventional consolidation treatments (ethyl silicate; methylacrylate-ethylmethacrylate copolymer and polyvinyl butyral). Conventional products do not reach in-depth consolidation, typically forming a thin impervious surface layer which blocks pores. In contrast, the bacterial treatment produces vaterite (CaCO3) biocement, which does not block pores and produces a good level of consolidation, both at the surface and in-depth, as shown by drilling resistance measurement system analyses. Transmission electron microscopy analyses show that bacterial vaterite cement formed via oriented aggregation of CaCO3 nanoparticles (∼20nm in size), resulting in mesocrystals which incorporate bacterial biopolymers. Such a biocomposite has superior mechanical properties, thus explaining the fact that drilling resistance of bioconsolidated gypsum plasters is within the range of inorganic calcite materials of equivalent porosity, despite the fact that the bacterial vaterite cement accounts for only a 0.02 solid volume fraction. Bacterial bioconsolidation is proposed for the effective consolidation of this type of material. The potential applications of bacterial calcium carbonate consolidation of gypsum biomaterials used as bone graft substitutes are discussed. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Fate of Mercury in Synthetic Gypsum Used for Wallboard Production

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

Jessica Sanderson; Gary M. Blythe; Mandi Richardson

2006-12-01

expected to impact the stability of mercury in synthetic gypsum used to produce wallboard, so Task 6 was added to the project to test this theory. In this project, process stacks in the wallboard plant have been sampled using the Ontario Hydro method. For every task, the stack locations sampled have included a dryer for the wet gypsum as it enters the plant and a gypsum calciner. For Tasks 1, 4, 5 and 6, the stack of the dryer for the wet wallboard product was also tested. Also at each site, in-stream process samples were collected and analyzed for mercury concentration before and after each significant step in wallboard production. The Ontario Hydro results, process sample mercury concentration data, and process data were used to construct mercury mass balances across the wallboard plants. Task 6 was conducted at a wallboard plant processing synthetic gypsum from a power plant that fires Eastern bituminous coal. The power plant has a single-loop, open spray tower limestone forced oxidation FGD system, with the forced oxidation conducted in the reaction tank integral with the FGD absorber. The FGD system has gypsum fines blow down as part of the dewatering step. The power plant is equipped with a selective catalytic reduction (SCR) system for NOX emissions control, and the SCR was in service during the time period the gypsum tested was produced. Also, as mentioned above, Degussa additive TMT-15 was being added to the FGD system when this gypsum was produced. The results of the Task 6 stack testing, as measured by the Ontario Hydro method, detected that an average of 55% of the incoming mercury was emitted during wallboard production. These losses were distributed as about 4% across the dryer mill, 6% across the board dryer kiln, and 45% across the kettle calciner. Emissions were similar to what Task 5 results showed on a percentage basis, but about 30% lower on a mass basis. The same power plant FGD system produced the synthetic gypsum used in Task 5 (with no use of TMT-15

Evaluation of potential for mercury volatilization from natural and FGD gypsum products using flux-chamber tests.

PubMed

Shock, Scott S; Noggle, Jessica J; Bloom, Nicholas; Yost, Lisa J

2009-04-01

Synthetic gypsum produced by flue-gas desulfurization (FGD) in coal-fired power plants (FGD gypsum) is put to productive use in manufacturing wallboard. FGD gypsum wallboard is widely used, accounting for nearly 30% of wallboard sold in the United States. Mercury is captured in flue gas and thus is one of the trace metals present in FGD gypsum; raising questions about the potential for mercury exposure from wallboard. Mercury is also one of the trace metals present in "natural" mined gypsum used to make wall board. Data available in the literature were not adequate to assess whether mercury in wallboard from either FGD or natural gypsum could volatilize into indoor air. In this study, mercury volatilization was evaluated using small-scale (5 L) glass and Teflon flux chambers, with samples collected using both iodated carbon and gold-coated sand traps. Mercury flux measurements made using iodated carbon traps (n=6) were below the detection limit of 11.5 ng/m2-day for all natural and synthetic gypsum wallboard samples. Mercury flux measurements made using gold-coated sand traps (n=6) were 0.92 +/- 0.11 ng/m2-day for natural gypsum wallboard and 5.9 +/- 2.4 ng/m2-day for synthetic gypsum wallboard. Room air mercury concentrations between 0.028 and 0.28 ng/m3 and between 0.13 and 2.2 ng/m3 were estimated based on the flux-rate data for natural and synthetic gypsum wallboard samples, respectively, and were calculated assuming a 3 m x 4 m x 5 m room, and 10th and 90th percentile air exchange rates of 0.18/hour and 1.26/hour. The resulting concentration estimates are well below the U.S. Environmental Protection Agency (EPA) reference concentration for indoor air elemental mercury of 300 ng/m3 and the Agency for Toxic Substances and Disease Registry minimal risk level (MRL) of 200 ng/m3. Further, these estimates are below background mercury concentrations in indoor air and within or below the range of typical background mercury concentrations in outdoor air.

Gypsum under pressure: A first-principles study

NASA Astrophysics Data System (ADS)

Giacomazzi, Luigi; Scandolo, Sandro

2010-02-01

We investigate by means of first-principles methods the structural response of gypsum (CaSO4ṡ2H2O) to pressures within and above the stability range of gypsum-I (P≤4GPa) . Structural and vibrational properties calculated for gypsum-I are in excellent agreement with experimental data. Compression within gypsum-I takes place predominantly through a reduction in the volume of the CaO8 polyhedra and through a distortion of the hydrogen bonds. The distance between CaSO4 layers becomes increasingly incompressible, indicating a mechanical limit to the packing of water molecules between the layers. We find that a structure with collapsed interlayer distances becomes more stable than gypsum-I above about 5 GPa. The collapse is concomitant with a rearrangement of the hydrogen-bond network of the water molecules. Comparison of the vibrational spectra calculated for this structure with experimental data taken above 5 GPa supports the validity of our model for the high-pressure phase of gypsum.

Gypsum at Olympia Undae

NASA Technical Reports Server (NTRS)

2006-01-01

This Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) 'targeted image' shows a region of sand dunes surrounding the Martian north polar cap. CRISM, an instrument on NASA's Mars Reconnaissance Orbiter, acquired the image at 1811 UTC (2:11 p.m. EDT) on Oct. 1, 2006. The imaged site is near 80.0 degrees north latitude, 240.7 degrees east longitude. It covers an area about 12 kilometers (7.5 miles) square. At the center of the image, the spatial resolution is as good as 20 meters (65 feet) per pixel. The image was taken in 544 colors covering 0.36 to 3.92 micrometers.

CRISM's sister instrument on the Mars Express spacecraft, OMEGA, has spectrally mapped Mars at lower spatial resolution and discovered that several regions of the planet are rich in sulfate minerals formed by liquid water. Surprisingly, one of the sulfate-rich deposits is a part of the giant field of sand dunes surrounding the north polar cap. CRISM is remapping the dune field at about five times higher resolution than OMEGA, and imaging selected regions at 50 times higher resolution. This image is the first of the high-resolution images of the dune field.

This visualization includes two renderings of the data, both map-projected. The left images are false-color representations showing brightness of the surface at selected infrared wavelengths. The right images show strength of an absorption band at 1900 nanometers wavelength, which indicates the relative abundance of the sulfate mineral gypsum. Brighter areas have more gypsum, and darker areas have less gypsum. The bottom views are enlargements of the central part of the two versions of the image shown at top.

Gypsum is a light-colored, whitish mineral, so it was anticipated that gypsum-rich parts of the sand dunes would be light in color. In fact, there are light-colored areas in the left images, but the images of the gypsum absorption at right show that the light areas have only low gypsum abundance. The dark sand dunes

Physicochemical Properties and Cellular Responses of Strontium-Doped Gypsum Biomaterials

PubMed Central

Pouria, Amir; Bandegani, Hadis; Pourbaghi-Masouleh, Milad; Hesaraki, Saeed; Alizadeh, Masoud

2012-01-01

This paper describes some physical, structural, and biological properties of gypsum bioceramics doped with various amounts of strontium ions (0.19–2.23 wt%) and compares these properties with those of a pure gypsum as control. Strontium-doped gypsum (gypsum:Sr) was obtained by mixing calcium sulfate hemihydrate powder and solutions of strontium nitrate followed by washing the specimens with distilled water to remove residual salts. Gypsum was the only phase found in the composition of both pure and gypsum:Sr, meanwhile a shift into lower diffraction angles was observed in the X-ray diffraction patterns of doped specimens. Microstructure of all gypsum specimens consisted of many rod-like small crystals entangled to each other with more elongation and higher thickness in the case of gypsum:Sr. The Sr-doped sample exhibited higher compressive strength and lower solubility than pure gypsum. A continuous release of strontium ions was observed from the gypsum:Sr during soaking it in simulated body fluid for 14 days. Compared to pure gypsum, the osteoblasts cultured on strontium-doped samples showed better proliferation rate and higher alkaline phosphatase activity, depending on Sr concentration. These observations can predict better in vivo behavior of strontium-doped gypsum compared to pure one. PMID:22719270

Gypsum crystals observed in experimental and natural sea ice

NASA Astrophysics Data System (ADS)

Geilfus, N.-X.; Galley, R. J.; Cooper, M.; Halden, N.; Hare, A.; Wang, F.; Søgaard, D. H.; Rysgaard, S.

2013-12-01

gypsum has been predicted to precipitate in sea ice, it has never been observed. Here we provide the first report on gypsum precipitation in both experimental and natural sea ice. Crystals were identified by X-ray diffraction analysis. Based on their apparent distinguishing characteristics, the gypsum crystals were identified as being authigenic. The FREeZing CHEMistry (FREZCHEM) model results support our observations of both gypsum and ikaite precipitation at typical in situ sea ice temperatures and confirms the "Gitterman pathway" where gypsum is predicted to precipitate. The occurrence of authigenic gypsum in sea ice during its formation represents a new observation of precipitate formation and potential marine deposition in polar seas.

Geology of the Gypsum Gap quadrangle, Colorado

USGS Publications Warehouse

Cater, Fred W.

1953-01-01

The Gypsum Gap quadrangle is one eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comparative study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through a arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The core consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

Gypsum karst in Italy: a review

NASA Astrophysics Data System (ADS)

De Waele, Jo; Chiarini, Veronica; Columbu, Andrea; D'Angeli, Ilenia M.; Madonia, Giuliana; Parise, Mario; Piccini, Leonardo; Vattano, Marco; Vigna, Bartolomeo; Zini, Luca; Forti, Paolo

2016-04-01

Although outcropping only rarely in Italy, gypsum karst has been described in detail since the early XXth century (Marinelli, 1917). Gypsum caves are now known from almost all Italian regions (Madonia & Forti, 2003), but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche regions), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum quarries in Piedmont (Vigna et al., 2010). During the late 80s and 90s several multidisciplinary studies have been carried out in many gypsum areas. All this work converged into a comprehensive overview in 2003 (Madonia & Forti, 2003). Further detailed studies focused on the gypsum areas of Emilia Romagna (Chiesi et al., 2010; Forti & Lucci, 2010; Demaria et al., 2012; De Waele & Pasini, 2013; Ercolani et al., 2013; Columbu et al., 2015; Lucci & Piastra, 2015; Tedeschi et al., 2015) and of Sicily (Madonia & Vattano, 2011). Sinkholes related to Permo-Triassic gypsum have been studied in Friuli Venezia Giulia (Zini et al., 2015). This presentation will review the state of the art regarding different aspects of evaporite karst in Italy focusing on the main new results. References Chiesi M., et al. (2010) - Origin and evolution of a salty gypsum/anhydrite karst spring: the case of Poiano (Northern Apennines, Italy). Hydrogeology Journal, 18, pp. 1111-1124. Columbu A. et al. (2015) - Gypsum caves as indicators of climate-driven river incision and aggradation in a rapidly uplifting region. Geology, 43(6), 539-542. Demaria D. et al. (Eds.) (2012), Le Grotte Bolognesi, GSB-USB, 431 p. De Waele J., Pasini G. (2013) - Intra-messinian gypsum palaeokarst in the northern Apennines and its palaeogeographic implications. Terra Nova 25, pp. 199-205. Ercolani M., et al. (Eds.) (2013), I Gessi e la Cave i Monte Tondo. Studio multidisciplinare di un'area carsica nella Vena del Gesso Romagnola. Memorie Ist. It. Spel. II(26), 559 p

Gypsum-bonded alumina dental investment for high-fusing casting.

PubMed

Yan, M; Takahashi, H

1998-09-01

In this study, we developed a new gypsum-bonded investment for high-fusing alloys. The investment was composed of gypsum as a binder and alumina as a refractory. Effects of type of alumina powder and gypsum content on characteristics of the gypsum-bonded alumina investment were investigated. Obtained characteristics of this experimental investment were as follows: fluidities ranged from 48.8 to 88.9 mm; setting times ranged from 21.2 to more than 120 minutes; setting expansions ranged from 0.4 to 1.3%; green strengths showed 0.5 to 4.5 MPa; fired strengths ranged from 0.2 to 1.7 MPa; thermal expansions after firing were -1.60 to 2.16%. Thermal expansion occurred because of the chemical reaction between Al2O3 and CaO decomposed from gypsum. These results suggest that this gypsum-bonded alumina investment with 20 or 25 mass% gypsum content possessed the fundamental properties for high-fusing alloy casting.

Flue gas desulfurization gypsum agricultural network alabama (cotton)

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization gypsum (FGDG) is an excellent source of gypsum (CaSO4•2H2O) that can be beneficially used in agriculture. Research was conducted as part of the Flue Gas Desulfurization Gypsum Agricultural Network program sponsored by the Electric Power Research Institute in collaboration wi...

Flue gas desulfurization gypsum agricultural network alabama (bermudagrass)

USDA-ARS?s Scientific Manuscript database

Synthetic gypsum is being produced in large quantities each year as a byproduct of SO2 removal from flue gas stream at coal-fired utility plants. This synthetic gypsum which is believed to be comparable or better than mined gypsum may enhance crop production. However, there is a paucity of informati...

Mineral of the month: gypsum

USGS Publications Warehouse

Founie, Alan

2004-01-01

The earliest known use of gypsum as a building material was in Anatolia (in what is now Turkey) around 6000 B.C. It has been found on the interiors of the great pyramids in Egypt, which were erected in about 3700 B.C. Now an average new American home contains more than 7 metric tons of gypsum in the form of more than 6,000 square feet of wallboard.

Effects of gypsum on trace metals in soils and earthworms

USDA-ARS?s Scientific Manuscript database

Mined gypsum has been beneficially used for many years as an agricultural amendment. Currently a large amount of flue gas desulfurization (FGD) gypsum is produced by removal of SO2 from flue gas streams when fuels with high S content are burned. The FGD gypsum, similar to mined gypsum, can enhance c...

Sustainable Uses of FGD Gypsum in Agricultural Systems: Introduction.

PubMed

Watts, Dexter B; Dick, Warren A

2014-01-01

Interest in using gypsum as a management tool to improve crop yields and soil and water quality has recently increased. Abundant supply and availability of flue gas desulfurization (FGD) gypsum, a by-product of scrubbing sulfur from combustion gases at coal-fired power plants, in major agricultural producing regions within the last two decades has attributed to this interest. Currently, published data on the long-term sustainability of FGD gypsum use in agricultural systems is limited. This has led to organization of the American Society of Agronomy's Community "By-product Gypsum Uses in Agriculture" and a special collection of nine technical research articles on various issues related to FGD gypsum uses in agricultural systems. A brief review of FGD gypsum, rationale for the special collection, overviews of articles, knowledge gaps, and future research directions are presented in this introductory paper. The nine articles are focused in three general areas: (i) mercury and other trace element impacts, (ii) water quality impacts, and (iii) agronomic responses and soil physical changes. While this is not an exhaustive review of the topic, results indicate that FGD gypsum use in sustainable agricultural production systems is promising. The environmental impacts of FGD gypsum are mostly positive, with only a few negative results observed, even when applied at rates representing cumulative 80-year applications. Thus, FGD gypsum, if properly managed, seems to represent an important potential input into agricultural systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The Gypsum: White gold of Rajasthan, introduction, uses and future prospective

NASA Astrophysics Data System (ADS)

Sharma, Gayatri

2013-06-01

Rajasthan is mineral based state and Bikaner and its surrounding district have been gifted with Gypsum. Mt of Gypsum is available in these districts. Gypsum has multiple uses including basic raw material for POP industry, addition in cement and a natural fertilizer. This mineral has changes the economic scenario in the remote areas of Bikaner, Nagaur, Hanumangarh, Sanchore, Shriganganagar etc. Gypsum and selenite are mined about 3.0 million tons per year. There is huge demand from cement industry as Gypsum is added for improving setting time of cement. Gypsum is a natural fertilizer for alkaline land and it role is vital in state like India where alkaline land is major role. Its high use as fertilizer has potential to change millions of poor farmer families and improving in crop production. Cement Industry has started importing Gypsum from Thailand, Bankong, Pakistan, Iran etc. The mining of gypsum of purity of 70% CaSO4.2H2O is cooperative effort between the land owners and Rajasthan State Mines and Minerals Limited. Gypsum fulfills the demand of POP and Cement industry in Rajasthan and powder gypsum used in agriculture for recon dining of alkaline soil. This paper deals with multiple uses, availability, and future prospective of Gypsum, a white gold of Rajasthan.

Optimization of the gypsum-based materials by the sequential simplex method

NASA Astrophysics Data System (ADS)

Doleželová, Magdalena; Vimmrová, Alena

2017-11-01

The application of the sequential simplex optimization method for the design of gypsum based materials is described. The principles of simplex method are explained and several examples of the method usage for the optimization of lightweight gypsum and ternary gypsum based materials are given. By this method lightweight gypsum based materials with desired properties and ternary gypsum based material with higher strength (16 MPa) were successfully developed. Simplex method is a useful tool for optimizing of gypsum based materials, but the objective of the optimization has to be formulated appropriately.

Method Analysis of Microbial Resistant Gypsum Products

EPA Science Inventory

Abstract: Several commercially available gypsum products are marketed as microbial-resistant. During previous test method research on a microbial resistant gypsum wallboard study, a common theme from both stakeholders and product vendors was the need for a unified and accepted m...

Gypsum-karst problems in constructing dams in the USA

USGS Publications Warehouse

Johnson, K.S.

2008-01-01

Gypsum is a highly soluble rock and is dissolved readily to form caves, sinkholes, disappearing streams, and other karst features that typically are also present in limestones and dolomites. Gypsum karst is widespread in the USA and has caused problems at several sites where dams were built, or where dam construction was considered. Gypsum karst is present (at least locally) in most areas where gypsum crops out, or is less than 30-60 m below the land surface. These karst features can compromise on the ability of a dam to hold water in a reservoir, and can even cause collapse of a dam. Gypsum karst in the abutments or foundation of a dam can allow water to pass through, around, or under a dam, and solution channels can enlarge quickly, once water starts flowing through such a karst system. The common procedure for controlling gypsum karst beneath the dam is a deep cut-off trench, backfilled with impermeable material, or a close-spaced grout curtain that hopefully will fill all cavities. In Oklahoma, the proposed Upper Mangum Dam was abandoned before construction, because of extensive gypsum karst in the abutments and impoundment area. Catastrophic failure of the Quail Creek Dike in southwest Utah in 1989 was due to flow of water through an undetected karstified gypsum unit beneath the earth-fill embankment. The dike was rebuilt, at a cost of US $12 million, with construction of a cut-off trench 600 m long and 25 m deep. Other dams in the USA with severe gypsum-karst leakage problems in recent years are Horsetooth and Carter Lake Dams, in Colorado, and Anchor Dam, in Wyoming. ?? 2007 Springer-Verlag.

Measuring the gypsum content of C&D debris fines.

PubMed

Musson, Stephen E; Xu, Qiyong; Townsend, Timothy G

2008-11-01

Construction and demolition (C&D) debris recycling facilities often produce a screened material intended for use as alternative daily cover (ADC) at active landfills or for shaping and grading at closed landfills. This product contains soil and small pieces of wood, concrete, gypsum drywall, shingles and other components of C&D debris. Concerns have been raised over the contribution of gypsum drywall in C&D debris fines to odor problems at landfills where the product is used. To address such concerns, limitations may be placed on the percentage of gypsum (or sulfate) that can occur, and standardized testing procedures are required to permit valid compliance testing. A test procedure was developed for measuring the gypsum content in C&D debris fines. The concentration of sulfate leached in an aqueous solution was used to estimate the initial gypsum content of the sample. The impact of sample size and leaching time were evaluated. Precision and accuracy increased with increasing gypsum content. Results from replicate samples had an average relative standard deviation of 9%. The gypsum content of fines obtained from different facilities in the US varied widely from 1% to over 25%. These variations not only occurred between differing facilities, but within batches produced within a single facility.

Raman spectroscopy of shocked gypsum from a meteorite impact crater

NASA Astrophysics Data System (ADS)

Brolly, Connor; Parnell, John; Bowden, Stephen

2017-07-01

Impact craters and associated hydrothermal systems are regarded as sites within which life could originate on Earth, and on Mars. The Haughton impact crater, one of the most well preserved craters on Earth, is abundant in Ca-sulphates. Selenite, a transparent form of gypsum, has been colonized by viable cyanobacteria. Basement rocks, which have been shocked, are more abundant in endolithic organisms, when compared with un-shocked basement. We infer that selenitic and shocked gypsum are more suitable for microbial colonization and have enhanced habitability. This is analogous to many Martian craters, such as Gale Crater, which has sulphate deposits in a central layered mound, thought to be formed by post-impact hydrothermal springs. In preparation for the 2020 ExoMars mission, experiments were conducted to determine whether Raman spectroscopy can distinguish between gypsum with different degrees of habitability. Ca-sulphates were analysed using Raman spectroscopy and results show no significant statistical difference between gypsum that has experienced shock by meteorite impact and gypsum, which has been dissolved and re-precipitated as an evaporitic crust. Raman spectroscopy is able to distinguish between selenite and unaltered gypsum. This shows that Raman spectroscopy can identify more habitable forms of gypsum, and demonstrates the current capabilities of Raman spectroscopy for the interpretation of gypsum habitability.

Gypsum crystallization from cadmium-poisoned solutions

NASA Astrophysics Data System (ADS)

Rinaudo, C.; Franchini-Angela, M.; Boistelle, R.

1988-06-01

Gypsum crystals, CaSO4⋯2H2O, are grown from solutions containing large amounts of cadmium chloride as an impurity. The initial supersaturations necessary for the gypsum nucleation increase with increasing cadmium concentration. Accordingly, at constant initial supersaturation, the induction periods also increase with increasing cadmium concentration. Cadmium and chlorine are incorporated into the crystals probably as CdCl+ or CdCl2, which are the most abundant complexes in the solutions. Consequently, the gypsum crystals grow curved, distorted and exhibit fractures along the [100] direction. The amount of incorporated cadmium increases with increasing supersaturation. Cadmium is mainly detected near the {120} faces in the area where the fractures release the internal stresses. Supersaturation and concentration of free ions and complexes are calculated for all solutions. Adsorption on {120} is discussed.

Study of heat and mass transfer of water evaporation in a gypsum board subjected to natural convection

NASA Astrophysics Data System (ADS)

Zannouni, K.; El Abrach, H.; Dhahri, H.; Mhimid, A.

2017-06-01

The present paper reports a numerical study to investigate the drying of rectangular gypsum sample based on a diffusive model. Both vertical and low sides of the porous media are treated as adiabatic and impermeable surfaces plate. The upper face of the plate represents the permeable interface. The energy equation model is based on the local thermal equilibrium assumption between the fluid and the solid phases. The lattice Boltzmann method (LBM) is used for solving the governing differential equations system. The obtained numerical results concerning the moisture content and the temperature within a gypsum sample were discussed. A comprehensive analysis of the influence of the mass transfer coefficient, the convective heat transfer coefficient, the external temperature, the relative humidity and the diffusion coefficient on macroscopic fields are also investigated. They all presented results in this paper and obtained in the stable regime correspond to time superior than 4000 s. Therefore the numerical error is inferior to 2%. The experimental data and the descriptive information of the approach indicate an excellent agreement between the results of our developed numerical code based on the LBM and the published ones.

Fractography of cast gypsum.

PubMed

Mori, T; Yamane, M

1982-02-01

A fractographical study of dental cast gypsum was made in order to correlate the mechanical properties with the microstructure. Wet specimens fractured under tensile stress showed intercrystalline fracture and the tensile strength depended on the porosity present. Thus, it was assumed that tensile strength was dependent on the contact area between individual gypsum crystals and changes in porosity approximated to changes in contact area. Strength differences among specimens of a given W/P ratio, therefore, can be related to differences in intercrystalline contact areas. These theoretical considerations suggest that the classification of dental die stone and dental stone into high and low strength types based on strength properties only would be more practical and less confusing than at present.

Alfalfa Responses to Gypsum Application Measured Using Undisturbed Soil Columns

PubMed Central

Tirado-Corbalá, Rebecca; Slater, Brian K.; Dick, Warren A.; Barker, Dave

2017-01-01

Gypsum is an excellent source of Ca and S, both of which are required for crop growth. Large amounts of by-product gypsum [Flue gas desulfurization gypsum-(FGDG)] are produced from coal combustion in the United States, but only 4% is used for agricultural purposes. The objective of this study was to evaluate the effects of (1) untreated, (2) short-term (4-year annual applications of gypsum totaling 6720 kg ha−1), and (3) long-term (12-year annual applications of gypsum totaling 20,200 kg ha−1) on alfalfa (Medicago sativa L.) growth and nutrient uptake, and gypsum movement through soil. The study was conducted in a greenhouse using undisturbed soil columns of two non-sodic soils (Celina silt loam and Brookston loam). Aboveground growth of alfalfa was not affected by gypsum treatments when compared with untreated (p > 0.05). Total root biomass (0–75 cm) for both soils series was significantly increased by gypsum application (p = 0.04), however, increased root growth was restricted to 0–10 cm depth. Soil and plant analyses indicated no unfavorable environmental impact from of the 4-year and 12-year annual application of FGDG. We concluded that under sufficient water supply, by-product gypsum is a viable source of Ca and S for land application that might benefit alfalfa root growth, but has less effect on aboveground alfalfa biomass production. Undisturbed soil columns were a useful adaptation of the lysimeter method that allowed detailed measurements of alfalfa nutrient uptake, root biomass, and yield and nutrient movement in soil. PMID:28696383

Fate of Mercury in Synthetic Gypsum Used for Wallboard Production

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

Jessica Marshall Sanderson

2006-06-01

This report presents and discusses results from Task 5 of the study ''Fate of Mercury in Synthetic Gypsum Used for Wallboard Production,'' performed at a full-scale commercial wallboard plant. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. The FGD process is used to control the sulfur dioxide emissions which would result in acid rain if not controlled. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasingmore » the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies developed for power plants involve the capture of mercury in FGD systems. The objective of this study is to determine whether any mercury is released into the atmosphere when the synthetic gypsum material is used as a feedstock for wallboard production. The project is being co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope includes five discrete tasks, each conducted at various USG wallboard plants using synthetic gypsum from different FGD systems. The five tasks were to include (1) a baseline test, then variations representing differing power plant (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5, which was to evaluate gypsum produced from an alternate FGD reagent, could not be conducted as planned. Instead, Task 5 was conducted at conditions similar to a previous task, Task 3, although with gypsum from an alternate FGD system. In this project, process stacks in the wallboard plant have been sampled using the Ontario Hydro method

XRD and mineralogical analysis of gypsum dunes at White Sands National Monument, New Mexico and applications to gypsum detection on Mars

NASA Astrophysics Data System (ADS)

Lafuente, B.; Bishop, J. L.; Fenton, L. K.; King, S. J.; Blake, D.; Sarrazin, P.; Downs, R.; Horgan, B. H.

2013-12-01

A field portable X-ray Diffraction (XRD) instrument was used at White Sands National Monument to perform in-situ measurements followed by laboratory analyses of the gypsum-rich dunes and to determine its modal mineralogy. The field instrument is a Terra XRD (Olympus NDT) based on the technology of the CheMin (Chemistry and Mineralogy) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity which is providing the mineralogical and chemical composition of scooped soil samples and drilled rock powders collected at Gale Crater [1]. Using Terra at White Sands will contribute to 'ground truth' for gypsum-bearing environments on Mars. Together with data provided by VNIR spectra [2], this study clarifies our understanding of the origin and history of gypsum-rich sand dunes discovered near the northern polar region of Mars [3]. The results obtained from the field analyses performed by XRD and VNIR spectroscopy in four dunes at White Sands revealed the presence of quartz and dolomite. Their relative abundance has been estimated using the Reference Intensity Ratio (RIR) method. For this study, particulate samples of pure natural gypsum, quartz and dolomite were used to prepare calibration mixtures of gypsum-quartz and gypsum-dolomite with the 90-150μm size fractions. All single phases and mixtures were analyzed by XRD and RIR factors were calculated. Using this method, the relative abundance of quartz and dolomite has been estimated from the data collected in the field. Quartz appears to be present in low amounts (2-5 wt.%) while dolomite is present at percentages up to 80 wt.%. Samples from four dunes were collected and prepared for subsequent XRD analysis in the lab to estimate their composition and illustrate the changes in mineralogy with respect to location and grain size. Gypsum-dolomite mixtures: The dolomite XRD pattern is dominated by an intense diffraction peak at 2θ≈36 deg. which overlaps a peak of gypsum, This makes low concentrations of dolomite

Porosity change after gypsum crust formation on macro-porous limestones

NASA Astrophysics Data System (ADS)

Dewanckele, Jan; Cnudde, Veerle; de Kock, Tim; Boone, Marijn; Boone, Matthieu; van Hoorebeke, Luc; Jacobs, Patric

2010-05-01

The deterioration of stone is a complex process in which physical, biological and chemical mechanisms are involved. In this research, pore structure changes inside two types of porous limestone were analyzed before, during and after strong acid tests with SO2. Sulphatation and crust formation phenomena on natural building stones exposed to a polluted environment, are largely described in literature. As far as rocks rich in calcium carbonate are concerned, the main processes involved are the dissolution of the calcium carbonate and the formation of gypsum (CaSO4.2H2O) in presence of an acid atmosphere. The low mobility of this newly formed salt favours its accumulation in porous materials and at the surface of less porous media. The main actor in the process of gypsum crystallization on limestone is the aggressive sulphur dioxide gas (SO2). In this study, the Savonnières and Euville limestone were subjected to tests with a strong acid. According to the standard EN 13919:2002E, samples were put in acid environment for 21 days. At the bottom of the container a mixture of 500 ± 10 ml H2SO3 and 150 ± 10 ml de-mineralized H2O was added. No airborne particles or oxides of nitrogen (NOx) were added. Before exposure, after 6 days in the polluted environment and at the end of the test, the two samples were scanned with X-ray computed tomography (X-ray CT) at the Centre for X-ray Tomography at Ghent University, Belgium (UGCT; www.ugct.ugent.be). This visualization technique allows 2D and 3D reconstructions on a micrometer scale of the internal structure of an object without damaging the material. It thus enables to scan the same sample in a sequential way. In order to obtain information about the sample's interior of which the characteristics can be compared before, during and after the test, the same scanning parameters (exposure time, amount of frames, energy, etc.) were used. In addition, the same adjustments like beam hardening correction, normalizing, ring and spot

Impact of welan gum on tricalcium aluminate-gypsum hydration

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

Ma Lei, E-mail: malei198713@163.com; Zhao Qinglin, E-mail: zhaoqinglin@whut.edu.cn; Yao Chukang

The retarding effect of welan gum on tricalcium aluminate-gypsum hydration, as a partial system of ordinary Portland cement (OPC) hydration, was investigated with several methods. The tricalcium aluminate-gypsum hydration behavior in the presence or absence of welan gum was researched by field emission gun scanning electron microscopy, X-ray diffraction and zeta potential analysis. Meanwhile, we studied the surface electrochemical properties and adsorption characteristics of welan gum by utilizing a zeta potential analyzer and UV-VIS absorption spectrophotometer. By adding welan gum, the morphology change of ettringite and retardation of hydration stages in tricalcium aluminate-gypsum system was observed. Moreover, we detected themore » adsorption behavior and zeta potential inversion of tricalcium aluminate and ettringite, as well as a rapid decrease in the zeta potential of tricalcium aluminate-gypsum system. The reduction on nucleation rate of ettringite and hydration activity of C{sub 3}A was also demonstrated. Thus, through the adsorption effect, welan gum induces a retarding behavior in tricalcium aluminate-gypsum hydration. Highlights: Black-Right-Pointing-Pointer Adsorption characteristics of welan gum on C{sub 3}A and ettringite have been studied. Black-Right-Pointing-Pointer C{sub 3}A-gypsum hydration behavior and the hydration products are examined in L/S = 3. Black-Right-Pointing-Pointer Welan gum retards the process of C{sub 3}A-gypsum hydration. Black-Right-Pointing-Pointer The addition of welan gum changes the nucleation growth of ettringite.« less

Effect of gypsum application on enzymatic browning activity in lettuce.

PubMed

Chutichudet, Prasit; Chutichudet, B; Kaewsit, S

2009-09-15

A comprehensive study to evaluate calcium, in terms of gypsum (CaSO4.2H2O) by soil dressing application, on enzymatic browning activity of Polyphenol oxidase (PPO) and internal qualities was tested on lettuce var. Grand Rapids under field conditions. A factorial in completely randomized design was arranged with four replications. The results showed that plants-treated with 50 mg kg(-1) gypsum applied at 40 DAP had the maximal fresh weight of 25.83 g plant(-1). The internal qualities of the lettuce at harvest showed that plants treated with 50 mg kg(-1) gypsum had the maximal chlorophyll content (26.80 mg m(-2)), while all gypsum concentrations applied in this study, had less content of ascorbic acid than the control plants. Plants-treated with 100 mg kg(-1) gypsum affected to the lowest level of PPO activity at week 3 after transplanting. Furthermore, gypsum application had no effect to biomass, leaf colour, the contents of phenolic and quinone in lettuce at harvesting stage.

MARKETING OF BYPRODUCT GYPSUM FROM FLUE GAS DESULFURIZATION

EPA Science Inventory

The report gives results of an evaluation of the 1985 marketing potential of byproduct gypsum from utility flue gas desulfurization (FGD), for the area east of the Rocky Mountains, using the calculated gypsum production rates of 14 selected power plants. The 114 cement plants and...

Sustainable uses of FGD gypsum in agricultural systems

USDA-ARS?s Scientific Manuscript database

Interest in using gypsum as a management tool to improve crop yields and soil/water quality has recently increased. Abundant supply and availability of flue gas desulfurization (FGD) gypsum, a by-product of scrubbing sulfur (S) from combustion gases at coal-fired power plants, in major agricultural...

Gypsum as a bedding source for broiler chickens

USDA-ARS?s Scientific Manuscript database

Three trials examined the feasibility of flue gas desulfurization gypsum as a bedding material for raising broilers. Gypsum was used alone, under or on top of pine shavings and pine bark. Test materials were placed as bedding in pens to simulate commercial broiler production through three growout cy...

The crystallization water of gypsum rocks is a relevant water source for plants.

PubMed

Palacio, Sara; Azorín, José; Montserrat-Martí, Gabriel; Ferrio, Juan Pedro

2014-08-18

Some minerals, like gypsum, hold water in their crystalline structure. Although still unexplored, the use of such crystallization water by organisms would point to a completely new water source for life, critical under dry conditions. Here we use the fact that the isotopic composition of free water differs from gypsum crystallization water to show that plants can use crystallization water from the gypsum structure. The composition of the xylem sap of gypsum plants during summer shows closer values to gypsum crystallization water than to free soil water. Crystallization water represents a significant water source for organisms growing on gypsum, especially during summer, when it accounts for 70-90% of the water used by shallow-rooted plants. Given the widespread occurrence of gypsum in dry lands throughout the Earth and in Mars, these results may have important implications for arid land reclamation and exobiology.

Testing antimicrobial cleaner efficacy on gypsum wallboard contaminated with Stachybotrys chartarum.

PubMed

Menetrez, Marc Y; Foarde, Karin K; Webber, Tricia D; Dean, Timothy R; Betancourt, Doris A

2007-11-01

Reducing occupant exposure to indoor mold is the goal of this research, through the efficacy testing of antimicrobial cleaners. Often mold contaminated building materials are not properly removed, but instead surface cleaners are applied in an attempt to alleviate the problem. The efficacy of antimicrobial cleaners to remove, eliminate or control mold growth on surfaces can easily be tested on non-porous surfaces. However, the testing of antimicrobial cleaner efficacy on porous surfaces, such as those found in the indoor environment such as gypsum board can be more complicated and prone to incorrect conclusions regarding residual organisms. The mold Stachybotrys chartarum has been found to be associated with idiopathic pulmonary hemorrhage in infants and has been studied for toxin production and its occurrence in water damaged buildings. Growth of S. chartarum on building materials such as gypsum wallboard has been frequently documented. Research to control S. chartarum growth using 13 separate antimicrobial cleaners on contaminated gypsum wallboard has been performed in laboratory testing. Popular brands of cleaning products were tested by following directions printed on the product packaging. A variety of gypsum wallboard surfaces were used to test these cleaning products at high relative humidity. The results indicate differences in antimicrobial efficacy for the six month period of testing. Results for the six types of GWB surfaces varied extensively. However, three cleaning products exhibited significantly better results than others. Lysol All-Purpose Cleaner-Orange Breeze (full strength) demonstrated results which ranked among the best in five of the six surfaces tested. Both Borax and Orange Glo Multipurpose Degreaser demonstrated results which ranked among the best in four of the six surfaces tested. The best antimicrobial cleaner to choose is often dependent on the type of surface to be cleaned of S. chartarum contamination. For Plain GWB, no paint, the

Pre-contamination of new gypsum wallboard with potentially harmful fungal species.

PubMed

Andersen, B; Dosen, I; Lewinska, A M; Nielsen, K F

2017-01-01

Gypsum wallboard is a popular building material, but is also very frequently overgrown by Stachybotrys chartarum after severe and/or undetected water damage. The purpose of this study was to determine whether Stachybotrys and other fungi frequently isolated from wet gypsum wallboard are already present in the panels directly from the factory. Surface-disinfected gypsum disks were wetted with sterile water, sealed, and incubated for 70 days. The results showed that Neosartorya hiratsukae (≡ Aspergillus hiratsukae) was the most dominant fungus on the gypsum wallboard followed by Chaetomium globosum and Stachybotrys chartarum. Our results suggest that these three fungal species are already embedded in the materials, presumably in the paper/carton layer surrounding the gypsum core, before the panels reach the retailers/building site. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Initiation and growth of gypsum piercement structures in the Zechstein Basin

USGS Publications Warehouse

Williams-Stroud, S. C.; Paul, J.

1997-01-01

The importance of tectonic processes in initiating halite diapirs has become much better understood in recent years. Less well understood is the development of diapiric structures involving rocks composed predominantly of gypsum. Below about 1000 m, gypsum dehydrates to anhydrite, which often obscures primary sedimentary textures. If the strain associated with diapiric rise in the rock induces the transition to anhydrite, obliteration of primary features in the gypsum can be expected. In our study, we infer that the diapiric movement in the Werra Anhydrite member of cycle 1 of the Zechstein Formation of Europe occurred before the initial transition of gypsum to anhydrite based on the presence of pseudomorphs of bedded primary gypsum crystals, the overburden lithologies and depositional environment, and the mechanical properties of gypsum, anhydrite and carbonate rocks. Faulting and differential loading of a shallow overburden were the key components in initiating the gypsum diapirism. The transition to anhydrite occurred after burial and after cessation of diapirism. In comparison, the diapirism of calcium sulfate of the Leine Anhydrite into the Leine Halite members of cycle 3 of the Zechstein Formation probably occurred much later after burial and appears to have been triggered by halite diapirism, which in turn triggered the dehydration reaction, causing the calcium sulfate to become the incompetent phase relative to the halite. Published by Elsevier Science Ltd.

Properties study of cotton stalk fiber/gypsum composite

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

Li Guozhong; Yu Yanzhen; Zhao Zhongjian

This manuscript addresses treating cotton stalk fiber surface with styrene acrylic emulsion, which improves the interfacial combined state of cotton stalk fiber/gypsum composite effectively and improves its mechanical properties notably. Mixes less slag, ordinary Portland cement, etc., to modify gypsum base. The electron microscope was utilized to analyze and research on the effect on composite properties of the abovementioned mixtures.

Formation of natural gypsum megacrystals in Naica, Mexico

NASA Astrophysics Data System (ADS)

García-Ruiz, Juan Manuel; Villasuso, Roberto; Ayora, Carlos; Canals, Angels; Otálora, Fermín

2007-04-01

Exploration in the Naica mine (Chihuahua, Mexico) recently unveiled several caves containing giant, faceted, and transparent single crystals of gypsum (CaSO4•2H2O) as long as 11 m. These large crystals form at very low supersaturation. The problem is to explain how proper geochemical conditions can be sustained for a long time without large fluctuations that would trigger substantial nucleation. Fluid inclusion analyses show that the crystals grew from low-salinity solutions at a temperature of ˜54 °C, slightly below the one at which the solubility of anhydrite equals that of gypsum. Sulfur and oxygen isotopic compositions of gypsum crystals are compatible with growth from solutions resulting from dissolution of anhydrite previously precipitated during late hydrothermal mineralization, suggesting that these megacrystals formed by a self-feeding mechanism driven by a solution-mediated, anhydrite-gypsum phase transition. Nucleation kinetics calculations based on laboratory data show that this mechanism can account for the formation of these giant crystals, yet only when operating within the very narrow range of temperature identified by our fluid inclusion study. These singular conditions create a mineral wonderland, a site of scientific interest, and an extraordinary phenomenon worthy of preservation.

Fibrous gypsum veins as diffuse features and within fault zones: the case study of the Pisco Basin (Ica desert, southern Peru)

NASA Astrophysics Data System (ADS)

Rustichelli, Andrea; Di Celma, Claudio; Tondi, Emanuele; Baud, Patrick; Vinciguerra, Sergio

2016-04-01

New knowledge on patterns of fibrous gypsum veins, their genetic mechanisms, deformation style and weathering are provided by a field- and laboratory-based study carried out on the Neogene to Quaternary Pisco Basin sedimentary strata (porous sandstones, siltstones and diatomites) exposed in the Ica desert, southern Peru. Gypsum veins vary considerably in dimensions, attitudes and timing and can develop in layered and moderately fractured rocks also in the absence of evaporitic layers. Veins occur both as diffuse features, confined to certain stratigraphic levels, and localised within fault zones. Arrays formed by layer-bounded, mutually orthogonal sets of steeply-dipping gypsum veins are reported for the first time. Vein length, height and spacing depend on the thickness of the bed packages in which they are confined. Within fault zones, veins are partly a product of faulting but also inherited layer-bounded features along which faults are superimposed. Due to the different petrophysical properties with respect to the parent rocks and their susceptibility to textural and mineralogical modifications, water dissolution and rupture, gypsum veins may have a significant role in geofluid management. Depending on their patterns and grade of physical and chemical alteration, veins may influence geofluid circulation and storage, acting as barriers to flow and possibly also as conduits.

[The effect of disinfectant soaking on dental gypsum model size].

PubMed

Zhu, Cao-yun; Xu, Yun-wen; Xu, Kan

2012-12-01

To study the influence of disinfectant soaking on the dimensional stability of three kinds of dental gypsum model. Three commonly used gypsums ( type III,IV,Vtype) in clinic were used to make 24 specimens for 50 mm×15 mm×10 mm in size. One hour after release, the specimens were placed for 24 h. A digital caliper was used to measure the size of the gypsum model. Distilled water immersion was as used control, glutaraldehyde disinfectant and Metrix CaviCide disinfectant soaking were used for the experimental group. After soaking for 0.5h, the gypsum models were removed and placed for 0.5 h, 1 h, 2 h, 24 h. The size of the models was measured again using the same method. The data was analyzed with SPSS10.0 software package. The initial gypsum model length was (50.07±0.017) mm, (50.048±0.015) mm and (50.027±0.015) mm. After soaking for different times, the size of the model changed little, and the dimensions changed less than 0.01%. The results show that disinfectant soaking has no significant effect on dental model dimensions.

Hydrogen sulfide release from dairy manure storages containing gypsum bedding

USDA-ARS?s Scientific Manuscript database

Recycled gypsum products can provide a cost-effective bedding alternative for dairy producers. Manufacturers report reduced odors, moisture and bacteria in the stall environment when compared to traditional bedding. Gypsum provides a sulfate source that can be converted to hydrogen sulfide under ana...

Carbonate replacement of lacustrine gypsum deposits in two Neogene continental basins, eastern Spain

NASA Astrophysics Data System (ADS)

Anadón, P.; Rosell, L.; Talbot, M. R.

1992-07-01

Bedded nonmarine gypsum deposits in the Miocene Teruel and Cabriel basins, eastern Spain, are partly replaced by carbonate. The Libros gypsum (Teruel Graben) is associated with fossiliferous carbonate wackestones and finely laminated, organic matter-rich mudstones which accumulated under anoxic conditions in a meromictic, permanent lake. The gypsum is locally pseudomorphed by aragonite or, less commonly, replaced by calcite. Low δ 13C values indicate that sulphate replacement resulted from bacterial sulphate reduction processes that were favoured by anacrobic conditions and abundant labile organic matter in the sediments. Petrographic evidence and oxygen isotopic composition suggest that gypsum replacement by aragonite occurred soon after deposition. A subsequent return to oxidising conditions caused some aragonite to be replaced by diagenetic gypsum. Native sulphur is associated with some of these secondary gypsum occurrences. The Los Ruices sulphate deposits (Cabriel Basin) contain beds of clastic and selenitic gypsum which are associated with limestones and red beds indicating accumulation in a shallow lake. Calcite is the principal replacement mineral. Bacterial sulphate reduction was insignificant in this basin because of a scarcity of organic matter. Stable isotope composition of diagenetic carbonate indicates that gypsum replacement occurred at shallow burial depths due to contact with dilute groundwaters of meteoric origin. Depositional environment evidently has a major influence upon the diagenetic history of primary sulphate deposits. The quantity of preserved organic matter degradable by sulphate-reducing bacteria is of particular importance and, along with groundwater composition, is the main factor controlling the mechanism of gypsum replacement by carbonate.

Utilization of FGD gypsum in agriculture for environmental benefits

USDA-ARS?s Scientific Manuscript database

This paper will discuss the utilization of FGD gypsum in agriculture for environmental benefits. Gypsum (CaSO4 .2H2O) has been used as an agricultural soil amendment for over 250 years. It is a soluble source of calcium and sulfur for crops and has been shown to improve soil physical and chemical pr...

Evaluation of FGD-gypsum to improve forage production and reduce phosphorus lossed from Piedmont soils

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization gypsum (FGD-gypsum), a byproduct from coal fired electricity generators, has the potential for beneficial use in agricultural systems as a soil amendment. Similar to mined gypsum it can improve soil chemical and physical properties and increase crop productivity. FGD-gypsum ...

Tunisian gypsums: Characteristics and use in cement

NASA Astrophysics Data System (ADS)

Mahmoudi, Salah; Bennour, Ali; Chalwati, Youssef; Souidi, Khouloud; Thabet, Manel; Srasra, Ezzedine; Zargouni, Fouad

2016-09-01

Gypsum materials of hundred meters thickness and interbedded with marine claystones and limestones from different paleogeographic sectors in the Tunisian territory are studied to assess their suitability for cement production. For this reason, thirty representative samples are analysed by chemical, physical and geotechnical tests. The obtained results for the studied gypsum materials are compared to Tunisian and European norms and with the local cements, currently marketed and which obey international norms. Indeed, for all samples hydraulic modulus HM, silica modulus SM and alumina modulus AM vary from (2.37-2.44), (2.48-2.68) and (1.45-2.5), respectively; whereas the required values for these modulus are (1.5-2.5), (2-3) and (1.5-2.5). The same behavior is observed for mineralogical analyses of C3S, C2S, C3A and C4AF and compressive strength at different ages. Briefly, Tunisia contains important reserves of gypsum scattered and spread over the Tunisian territory and can be used for cement production.

Gypsum Formation during the Messinian Salinity Crisis: an Alternative Model

NASA Astrophysics Data System (ADS)

Grothe, A.; Krijgsman, W.; Sangiorgi, F.; Vasiliev, I.; Baak, C. V.; Wolthers, M.; Stoica, M.; Reichart, G. J.; Davies, G.

2016-12-01

During the Messinian Salinity Crisis (MSC; 5.97 - 5.33 Myr ago), thick packages of evaporites (gypsum and halite) were deposited in the Mediterranean Basin. Traditionally, the occurrence of these evaporites is explained by the so-called "desiccation-model", in which evaporites are considered to result from a (partly) desiccated basin. In the last decade, it was thought that changes in the Mediterranean-Atlantic connectivity could explain the formation of gypsum. Stable isotope studies, however, show that the gypsum formed under influence of large freshwater input. Here we present new strontium isotope data from two well-dated Messinian sections in the Black and Caspian Seas. Our Sr isotope records suggest a persistent Mediterranean-Black Sea connection throughout the salinity crisis, which implies a large additional freshwater source to the Mediterranean. We claim that low saline waters from the Black Sea region are a prerequisite for gypsum formation in the Mediterranean and speculate about the mechanisms explaining this apparent paradox.

Spectral properties of Ca-sulfates: Gypsum, bassanite, and anhydrite

USGS Publications Warehouse

Bishop, Janice L.; Lane, Melissa D.; Dyar, M. Darby; King, Sara J.; Brown, Adrian J.; Swayze, Gregg A.

2014-01-01

This study of the spectral properties of Ca-sulfates was initiated to support remote detection of these minerals on Mars. Gypsum, bassanite, and anhydrite are the currently known forms of Ca-sulfates. They are typically found in sedimentary evaporites on Earth, but can also form via reaction of acidic fluids associated with volcanic activity. Reflectance, emission, transmittance, and Raman spectra are discussed here for various sample forms. Gypsum and bassanite spectra exhibit characteristic and distinct triplet bands near 1.4–1.5 μm, a strong band near 1.93–1.94 μm, and multiple features near 2.1–2.3 μm attributed to H2O. Anhydrite, bassanite, and gypsum all have SO4 combination and overtone features from 4.2–5 μm that are present in reflectance spectra. The mid-IR region spectra exhibit strong SO4 ν3 and ν4 vibrational bands near 1150–1200 and 600–680 cm−1 (~8.5 and 16 μm), respectively. Additional weaker features are observed near 1005–1015 cm−1 (~10 μm) for ν1 and near 470–510 cm−1 (~20 μm) for ν2. The mid-IR H2O bending vibration occurs near 1623–1630 cm−1 (~6.2 μm). The visible/near-infrared region spectra are brighter for the finer-grained samples. In reflectance and emission spectra of the mid-IR region the ν4 bands begin to invert for the finer-grained samples, and the ν1 vibration occurs as a band instead of a peak and has the strongest intensity for the finer-grained samples. The ν2 vibration is a sharp band for anhydrite and a broad peak for gypsum. The band center of the ν1 vibration follows a trend of decreasing frequency (increasing wavelength) with increasing hydration of the sample in the transmittance, Raman, and reflectance spectra. Anhydrite forms at elevated temperatures compared to gypsum, and at lower temperature, salt concentration, and pH than bassanite. The relative humidity controls whether bassanite or gypsum is stable. Thus, distinguishing among gypsum, bassanite, and anhydrite via

Effect of Time on Gypsum-Impression Material Compatibility

NASA Astrophysics Data System (ADS)

Won, John Boram

The purpose of this study was to evaluate the compatibility of dental gypsum with three recently introduced irreversible hydrocolloid (alginate) alternatives. The test materials were Alginot® (Kerr™), Position Penta Quick® (3M ESPE™) and Silgimix ® (Sultan Dental™). The irreversible hydrocolloid impression material, Jeltrate Plus antimicrobial® (Dentsply Caulk™) served as the control. Materials and Methods: Testing of materials was conducted in accordance with ANSI/ADA Specification No. 18 for Alginate Impression Materials. Statistical Analysis: The 3-Way ANOVA test was used to analyze measurements between different time points at a significance level of (p < 0.05). Outcome: It was found that there was greater compatibility between gypsum and the alternative materials over time than the traditional irreversible hydrocolloid material that was tested. A statistically significant amount of surface change/incompatibility was found over time with the combination of the dental gypsum products and the control impression material (Jeltrate Plus antimicrobial®).

Triple oxygen isotope systematics of structurally bonded water in gypsum

NASA Astrophysics Data System (ADS)

Herwartz, Daniel; Surma, Jakub; Voigt, Claudia; Assonov, Sergey; Staubwasser, Michael

2017-07-01

The triple oxygen isotopic composition of gypsum mother water (gmw) is recorded in structurally bonded water in gypsum (gsbw). Respective fractionation factors have been determined experimentally for 18O/16O and 17O/16O. By taking previous experiments into account we suggest using 18αgsbw-gmw = 1.0037; 17αgsbw-gmw = 1.00195 and θgsbw-gmw = 0.5285 as fractionation factors in triple oxygen isotope space. Recent gypsum was sampled from a series of 10 ponds located in the Salar de Llamara in the Atacama Desert, Chile. Total dissolved solids (TDS) in these ponds show a gradual increase from 23 g/l to 182 g/l that is accompanied by an increase in pond water 18O/16O. Gsbw falls on a parallel curve to the ambient water from the saline ponds. The offset is mainly due to the equilibrium fractionation between gsbw and gmw. However, gsbw represents a time integrated signal biased towards times of strong evaporation, hence the estimated gmw comprises elevated 18O/16O compositions when compared to pond water samples taken on site. Gypsum precipitation is associated with algae mats in the ponds with lower salinity. No evidence for respective vital effects on the triple oxygen isotopic composition of gypsum hydration water is observed, nor are such effects expected. In principle, the array of δ18Ogsbw vs. 17Oexcess can be used to: (1) provide information on the degree of evaporation during gypsum formation; (2) estimate pristine meteoric water compositions; and (3) estimate local relative humidity which is the controlling parameter of the slope of the array for simple hydrological situations. In our case study, local mining activities may have decreased deep groundwater recharge, causing a recent change of the local hydrology.

The astrobiological mission EXPOSE-R on board of the International Space Station

NASA Astrophysics Data System (ADS)

Rabbow, Elke; Rettberg, Petra; Barczyk, Simon; Bohmeier, Maria; Parpart, Andre; Panitz, Corinna; Horneck, Gerda; Burfeindt, Jürgen; Molter, Ferdinand; Jaramillo, Esther; Pereira, Carlos; Weiß, Peter; Willnecker, Rainer; Demets, René; Dettmann, Jan

2015-01-01

EXPOSE-R flew as the second of the European Space Agency (ESA) EXPOSE multi-user facilities on the International Space Station. During the mission on the external URM-D platform of the Zvezda service module, samples of eight international astrobiology experiments selected by ESA and one Russian guest experiment were exposed to low Earth orbit space parameters from March 10th, 2009 to January 21st, 2011. EXPOSE-R accommodated a total of 1220 samples for exposure to selected space conditions and combinations, including space vacuum, temperature cycles through 273 K, cosmic radiation, solar electromagnetic radiation at >110, >170 or >200 nm at various fluences up to GJ m-2. Samples ranged from chemical compounds via unicellular organisms and multicellular mosquito larvae and seeds to passive radiation dosimeters. Additionally, one active radiation measurement instrument was accommodated on EXPOSE-R and commanded from ground in accordance with the facility itself. Data on ultraviolet radiation, cosmic radiation and temperature were measured every 10 s and downlinked by telemetry and data carrier every few months. The EXPOSE-R trays and samples returned to Earth on March 9th, 2011 with Shuttle flight, Space Transportation System (STS)-133/ULF 5, Discovery, after successful total mission duration of 27 months in space. The samples were analysed in the individual investigators laboratories. A parallel Mission Ground Reference experiment was performed on ground with a parallel set of hardware and samples under simulated space conditions following to the data transmitted from the flight mission.

Properties of mortars made by uncalcined FGD gypsum-fly ash-ground granulated blast furnace slag composite binder

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

Zhong Shiyun, E-mail: tjzhongshiyun@163.com; Ni Kun; Li Jinmei

2012-07-15

Highlights: Black-Right-Pointing-Pointer The mortar with uncalcined FGD gypsum has suitable workability. Black-Right-Pointing-Pointer The strength of mortar with uncalcined FGD gypsum is higher than that of mortar without uncalcined FGD gypsum. Black-Right-Pointing-Pointer The dry shrinkage of mortar with uncalcined FGD gypsum is lower than that of mortar without uncalcined FGD gypsum. Black-Right-Pointing-Pointer The leaching of sulfate ion of mortar is studied. - Abstract: A series of novel mortars were developed from composite binder of uncalcined FGD gypsum, fly ash (FA) and ground granulated blast furnace slag (GGBFS) for the good utilization of flue gas desulphurization (FGD) gypsum. At a fixed ratiomore » (20%) of GGBFS to the composite binder, keeping consistency of the mortar between 9.5 and 10.0 cm, the properties of the composite mortar were studied. The results show that higher water/binder (W/B) is required to keep the consistency when increasing the percentage of FGD gypsum. No obvious influences of the W/B and content of FGD gypsum on the bleeding of paste were observed which keeps lower than 2% under all experimental conditions tried. The highest compressive and flexural strengths (ratio is 20% FGD gypsum, 20% GGBFS and 60% FA) are 22.6 and 4.3 MPa at 28 days, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that massive ettringite crystals and C-S-H gels exist in the hydration products. At 90 days the mortars with FGD gypsum is dramatically smaller drying shrinkage (563-938 micro strain) than that without FGD gypsum (about 2250 micro strain). The release of the SO{sub 4}{sup 2-} from the mortar was analyzed, indicating that the dissolution of sulfate increases with FGD gypsum. The concentration of SO{sub 4}{sup 2-} releasing from the mortar with 10% FGD gypsum is almost equal to that obtained from the mortar without FGD gypsum. The release of SO{sub 4}{sup 2-} from the mortar with 20% FGD gypsum is

Ballasting by cryogenic gypsum enhances carbon export in a Phaeocystis under-ice bloom.

PubMed

Wollenburg, J E; Katlein, C; Nehrke, G; Nöthig, E-M; Matthiessen, J; Wolf-Gladrow, D A; Nikolopoulos, A; Gázquez-Sanchez, F; Rossmann, L; Assmy, P; Babin, M; Bruyant, F; Beaulieu, M; Dybwad, C; Peeken, I

2018-05-16

Mineral ballasting enhances carbon export from the surface to the deep ocean; however, little is known about the role of this process in the ice-covered Arctic Ocean. Here, we propose gypsum ballasting as a new mechanism that likely facilitated enhanced vertical carbon export from an under-ice phytoplankton bloom dominated by the haptophyte Phaeocystis. In the spring 2015 abundant gypsum crystals embedded in Phaeocystis aggregates were collected throughout the water column and on the sea floor at a depth below 2 km. Model predictions supported by isotopic signatures indicate that 2.7 g m -2 gypsum crystals were formed in sea ice at temperatures below -6.5 °C and released into the water column during sea ice melting. Our finding indicates that sea ice derived (cryogenic) gypsum is stable enough to survive export to the deep ocean and serves as an effective ballast mineral. Our findings also suggest a potentially important and previously unknown role of Phaeocystis in deep carbon export due to cryogenic gypsum ballasting. The rapidly changing Arctic sea ice regime might favour this gypsum gravity chute with potential consequences for carbon export and food partitioning between pelagic and benthic ecosystems.

Development of fly ash boards with thermal, acoustic and fire insulation properties.

PubMed

Leiva, C; Arenas, C; Vilches, L F; Alonso-Fariñas, B; Rodriguez-Galán, M

2015-12-01

This paper presents an experimental analysis on a new board composed of gypsum and fly ashes from coal combustion, which are mutually compatible. Physical and mechanical properties, sound absorption coefficient, thermal properties and leaching test have been obtained. The mechanical properties showed similar values to other commercial products. As far as the acoustic insulation characteristics are concerned, sound absorption coefficients of 0.3 and 0.8 were found. The board presents a low thermal conductivity and a fire resistance higher than 50 min (for 4 cm of thickness). The leaching of trace elements was below the leaching limit values. These boards can be considered as suitable to be used in building applications as partitions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of FGD gypsum on soil fertility and plant nutrient uptake

USDA-ARS?s Scientific Manuscript database

Use of FGD gypsum is thought to improve soil productivity and increase plant production. Thus, a study was conducted to evaluate the effects of FGD gypsum on yield, plant nutrient uptake and soil productivity. The study was conducted on an established bermudagrass pasture. Poultry litter was applied...

Factors influencing gypsum crystal morphology within a flue gas desulfurization vessel

NASA Astrophysics Data System (ADS)

Lewis, Kinsey M.

Flue gas desulfurization (FGD) is utilized by the coal--powered generating industry to safely eliminate sulfur dioxide. A FGD vessel (scrubber) synthetically creates gypsum crystals by combining limestone (CaCO3), SO2 flue gas, water and oxygen resulting in crystalline gypsum (CaSO4 · 2H2O), which can be sold for an economic return. Flat disk--like crystals, opposed to rod--like crystals, are hard to dewater, lowering economic return. The objectives were to investigate the cause of varying morphologies, understand the environment of precipitation, as well as identify correlations between operating conditions and resulting unfavorable gypsum crystal growth. Results show evidence supporting airborne impurities due to the onsite coal pile, the abundance and size of CaCO 3 and high Ca:SO4 ratios within the scrubber as possible factors controlling gypsum crystal morphology. In conclusion, regularly purging the system and incorporating a filter on the air intake valve will provide an economic byproduct avoiding costly landfill deposits.

Calcium sulfoaluminate (Ye'elimite) hydration in the presence of gypsum, calcite, and vaterite

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

Hargis, Craig W.; Telesca, Antonio; Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu

Six calcium sulfoaluminate-based cementitious systems composed of calcium sulfoaluminate, calcite, vaterite, and gypsum were cured as pastes and mortars for 1, 7, 28 and 84 days. Pastes were analyzed with X-ray diffraction, thermogravimetric and differential thermal analyses. Mortars were tested for compressive strength, dimensional stability and setting time. Furthermore, pastes with a water/cementitious material mass ratio of 0.80 were tested for heat evolution during the first 48 h by means of isothermal conduction calorimetry. It has been found that: (1) both calcite and vaterite reacted with monosulfoaluminate to give monocarboaluminate and ettringite, with vaterite being more reactive; (2) gypsum loweredmore » the reactivity of both carbonates; (3) expansion was reduced by calcite and vaterite, irrespective of the presence of gypsum; and (4) both carbonates increased compressive strength in the absence of gypsum and decreased compressive strength less in the presence of gypsum, with vaterite's action more effective than that of calcite.« less

The Aspects About of Objectively Appraisals of Modeling Gypsum Quality and Composites of Phonic-Absorbent and Orthopedic on Base of Gypsum

NASA Astrophysics Data System (ADS)

Pop, P. A.; Ungur, P. A.; Lazar, L.; Marcu, F.

2009-11-01

The EU Norms about of protection environment, outside and inside ambient, and human health demands has lead at obtain of new materials on the base of airborne material, with high thermo and phonic-absorbent properties, porous and lightweight. The α and β-modeling gypsum plaster quality and lightweight depend on many factors as: fabrication process, granulation, roast temperature, work temperature, environment, additives used, breakage, etc. Also, the objectively appraisal of modeling gypsum quality depends of proper tests methods selection, which are legislated in norms, standards and recommendations. In Romanian Standards SR EN 13279-1/2005 and SR EN 13279-2/2005, adaptable from EU Norms EN 13279-1/2004 and EN 13279-2/2004, the characteristics gypsum family tests are well specification, as: granule-metric analysis, determination of water/plaster ratio, setting time, mechanical characteristics, adhesions and water restrain. For plaster with special use (phonic-absorbent and orthopedic materials, etc.) these determinations are not concluding, being necessary more parameters finding, as: elastic constant, phonic-absorbent coefficient, porosity, working, etc., which is imposed the completion of norms and standards with new determinations.

Towards the establishment of a general rate law for gypsum nucleation

NASA Astrophysics Data System (ADS)

Reznik, Itay J.; Ganor, Jiwchar; Gruber, Chen; Gavrieli, Ittai

2012-05-01

Gypsum nucleation kinetics from a wide range of chemical compositions (1.45 < Ca2+/SO42- < 115), ionic strengths (I = 2.5-10 m) and saturation state with respect to gypsum (Ωgyp = 1.07-8.4) were examined in batch experiments containing mixtures of Ca2+-rich Dead Sea brine and SO42-rich seawater with or without addition of extra Na2SO4 and CaCl2·2H2O. The induction times attained in the present study were compiled together with literature values from experiments carried out under significantly different conditions (synthetic NaCl solutions; I = 0.09-6.3 m; Ca2+/SO42- = 1; Ωgyp:1.59-7.76). Despite the variability in the experimental solutions, a single rate law based on classic nucleation theory was formulated to describe the induction times from more than 80 experiments: logT=log{1}/{3.17·Cs·exp{-}7.08ln2Ω}+0.072·Cs·exp-{1.426}/{ln2Ω} where Tind is the induction time, Cs is the solubility of gypsum and Ω is the saturation state with respect to gypsum. The rate law provides Tind for gypsum precipitation from aqueous solutions at 25 °C, containing no synthetic antiscalants or catalysts, within a 95% confidence interval within a factor of 5. Based on this rate law, we show that at present most of the precipitation of gypsum from the Dead Sea brine occurs following significant evaporation in the industrial evaporation ponds and not in the Dead Sea itself. Whereas Tind in Dead Sea brines is very long (on the order of 3 years), the evaporation of brine in the industrial ponds leads to increased Ω values, and thus to short Tind in the order of a few days. However, if seawater or reject brine from seawater desalinization will be introduced to the Dead Sea to restore its declining level, Tind will be significantly reduced and gypsum nucleation and precipitation will occur. For evaporated seawater, the proposed rate law predicts that even though saturation is obtained when seawater is evaporated by a factor of 2.8, gypsum will nucleate at reasonable times (few

Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils.

PubMed

Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

2015-06-01

Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline-alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation.

Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils

PubMed Central

Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

2015-01-01

Abstract Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline–alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation. PMID:26064038

Gypsum: a review of its role in the deterioration of building materials

NASA Astrophysics Data System (ADS)

Charola, A. Elena; Pühringer, Josef; Steiger, Michael

2007-03-01

The deterioration of buildings and monuments by gypsum is the result of crystallization cycles of this salt. Although gypsum can dehydrate to a hemihydrate, the mineral bassanite, and to an anhydrate, the mineral anhydrite, this reaction occurs in nature on a geological time scale and therefore it is unlikely to occur when gypsum is found on and in building materials. The CaSO4-H2O system appears deceptively simple, however there are still discrepancies between the experimental and thermodynamically calculated data. The reason for the latter can be attributed to the slow crystallization kinetics of anhydrite. Apart from this, the large numbers of studies carried out on this system have focused on industrially important metastable phases, such as the hemihydrate and soluble anhydrite. The paper presents a review of the studies dealing with the phase equilibria of the CaSO4-H2O system as well as the influence of other salts on the solubility of gypsum. It tries to glean out the relevant information that will serve to explain the deterioration observed on building materials by the crystallization of gypsum and thus allows developing improved conservation methods.

Gypsum and hydrohalite dynamics in sea ice brines

NASA Astrophysics Data System (ADS)

Butler, Benjamin M.; Papadimitriou, Stathys; Day, Sarah J.; Kennedy, Hilary

2017-09-01

Mineral authigenesis from their dissolved sea salt matrix is an emergent feature of sea ice brines, fuelled by dramatic equilibrium solubility changes in the large sub-zero temperature range of this cryospheric system on the surface of high latitude oceans. The multi-electrolyte composition of seawater results in the potential for several minerals to precipitate in sea ice, each affecting the in-situ geochemical properties of the sea ice brine system, the habitat of sympagic biota. The solubility of two of these minerals, gypsum (CaSO4 ·2H2O) and hydrohalite (NaCl · 2H2O), was investigated in high ionic strength multi-electrolyte solutions at below-zero temperatures to examine their dissolution-precipitation dynamics in the sea ice brine system. The gypsum dynamics in sea ice were found to be highly dependent on the solubilities of mirabilite and hydrohalite between 0.2 and - 25.0 ° C. The hydrohalite solubility between - 14.3 and - 25.0 ° C exhibits a sharp change between undersaturated and supersaturated conditions, and, thus, distinct temperature fields of precipitation and dissolution in sea ice, with saturation occurring at - 22.9 ° C. The sharp changes in hydrohalite solubility at temperatures ⩽-22.9 °C result from the formation of an ice-hydrohalite aggregate, which alters the structural properties of brine inclusions in cold sea ice. Favourable conditions for gypsum precipitation in sea ice were determined to occur in the region of hydrohalite precipitation below - 22.9 ° C and in conditions of metastable mirabilite supersaturation above - 22.9 ° C (investigated at - 7.1 and - 8.2 ° C here) but gypsum is unlikely to persist once mirabilite forms at these warmer (>-22.9 °C) temperatures. The dynamics of hydrohalite in sea ice brines based on its experimental solubility were consistent with that derived from thermodynamic modelling (FREZCHEM code) but the gypsum dynamics derived from the code were inconsistent with that indicated by its

MOISTURE MOVEMENT (WICKING) WITHIN GYPSUM WALLBOARD

EPA Science Inventory

Gypsum wallboard with repeated or prolonged exposure to water or excess moisture can lose its structural integrity and provide a growth medium for biological contaminants. Poorly sealed buildings, leaking or failed plumbing systems, or improperly constructed HVAC systems can all ...

Effects of FGD-gypsum, used-wallboard and calcium sulfate on corn and soybean root growth

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization (FGD)-gypsum production has increased 44 percent from 2007 to 2008. The major use of FGD-gypsum today is in the wallboard industry. Reduction in the construction, however, reduces the demand for wallboard. Agriculture could become the second largest user of FGD-gypsum. F...

Geochemical studies of northern taiga (gypsum) karst ecosystems and their high vulnerability to natural and anthropogenic hazards

NASA Astrophysics Data System (ADS)

Tuyukina, T. Yu.

2009-07-01

In the taiga gypsum karst ecosystems, gypsum soils formed on the hard gypsum substrates predominate in the soil cover. In these soils, the mineral horizons consist of 95-99% gypsum (CaSO4·2H2O) and the litter is the main horizon for nutrient accumulation. For this reason, the ecosystems are vulnerable to fire and erosion by walkers, from which they only recover slowly. Gypsum mining for industrial uses is also leading to the destruction of this unique ecosystem.

Potential of a gypsum-free composting process of wheat straw for mushroom production.

PubMed

Mouthier, Thibaut M B; Kilic, Baris; Vervoort, Pieter; Gruppen, Harry; Kabel, Mirjam A

2017-01-01

Wheat straw based composting generates a selective substrate for mushroom production. The first phase of this process requires 5 days, and a reduction in time is wished. Here, we aim at understanding the effect of gypsum on the duration of the first phase and the mechanism behind it. Hereto, the regular process with gypsum addition and the same process without gypsum were studied during a 5-day period. The compost quality was evaluated based on compost lignin composition analysed by py-GC/MS and its degradability by a commercial (hemi-)cellulolytic enzyme cocktail. The composting phase lead to the decrease of the pyrolysis products 4-vinylphenol and 4-vinylguaiacol that can be associated with p-coumarates and ferulates linking xylan and lignin. In the regular compost, the enzymatic conversion reached 32 and 39% for cellulose, and 23 and 32% for xylan after 3 and 5 days, respectively. In absence of gypsum similar values were reached after 2 and 4 days, respectively. Thus, our data show that in absence of gypsum the desired compost quality was reached 20% earlier compared to the control process.

Messinian Salinity Crisis' Primary Evaporites: the shallow gypsum vs. deep dolomite formation paradox solved

NASA Astrophysics Data System (ADS)

De Lange, G. J.; Krijgsman, W.

2015-12-01

The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, resulting in deposition of 1-3 km thick evaporites at the Mediterranean seafloor. A considerable, long-lasting controversy existed on the modes of their formation, including the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions at a precessional rhythm. Gypsum precipitation only occurred at marginal- and dolomite formation at deeper settings. A range of potential explanations was given, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are commonly neglected but may explain that different deposits formed in shallow vs deep environments without exceptional physical boundary conditions for each. A unifying mechanism is presented in which gypsum formation occurs at all shallow water depths but its preservation is limited to shallow sedimentary settings. In contrast, ongoing deep-basin anoxic organic matter (OM) degradation processes result in dolomite formation. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always oversaturated relative to dolomite but its formation is inhibited by the presence of dissolved sulphate. Thus conditions for formation of gypsum exclude those for formation of dolomite and vice versa. Another process linking the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, ongoing OM-degradation may result in reducing the sulphate and enhancing the dissolved carbonate content. Such low-sulphate / high carbonate conditions in MSC deepwater are. unfavorable for gypsum preservation and favorable for dolomite formation, and always coincide with anoxic, i.e. oxygen-free conditions. Including dynamic biogeochemical processes in the thusfar static

Evolution of limited seed dispersal ability on gypsum islands.

PubMed

Schenk, John J

2013-09-01

Dispersal is a major feature of plant evolution that has many advantages but is not always favored. Wide dispersal, for example, leads to greater seed loss in oceanic-island endemics, and evolution has favored morphologies that limit dispersal. I tested the hypothesis that selection favored limited dispersal on gypsum islands in western North America, where edaphic communities are sparsely vegetated except for a specialized flora that competes poorly with the surrounding flora. • I applied a series of comparative phylogenetic approaches to gypsophilic species of Mentzelia section Bartonia (Loasaceae) to investigate the evolution of limited dispersal function in seed wings, which increase primary dispersal by wind. Through these tests, I determined whether narrowed wings were selected for in gypsophilic species. • Gypsophily was derived four to seven times. Seed area was not significantly correlated with gypsophily or wing area. Wing area was significantly smaller in the derived gypsum endemics, supporting the hypothesis in favor of limited dispersal function. A model-fitting approach identified two trait optima in wing area, with gypsum endemics having a lower optimum. • Evolution into novel ecologies influences morphological evolution. Morphological characters have been selected for limited dispersal following evolution onto gypsum islands. Selection for limited dispersal ability has occurred across animals and plants, both in oceanic and terrestrial systems, which suggests that reduced dispersal ability may be a general process: selection favors limited dispersal if the difference in survival between the habitat of the parent and the surrounding area is great enough.

Permian paleogeography of west-central Pangea: Reconstruction using sabkha-type gypsum-bearing deposits of Parnaíba Basin, Northern Brazil

NASA Astrophysics Data System (ADS)

Abrantes, Francisco R.; Nogueira, Afonso C. R.; Soares, Joelson L.

2016-07-01

Extreme aridity during Late Permian - Early Triassic period was the main factor for resetting the entire paleoclimate of the planet. Permian evaporite basins and lacustrine red beds were widely distributed along the supercontinent of Pangea. Sulphate deposits in Western Pangea, particularly in Northern Brazil, accumulated in an extensive playa lake system. Outcrop-based facies and stratigraphic analysis of up to 20 m thick evaporite-siliciclastic deposits reveal the predominance of laminated reddish mudstone with subordinate limestone, marl and lenses of gypsum. The succession was deposited in shallow lacustrine and inland sabkha environments associated with saline pans and mudflats. Gypsum deposits comprise six lithofacies: 1) bottom-growth gypsum, 2) nodular/micronodular gypsum, 3) mosaic gypsum, 4) fibrous/prismatic gypsum, 5) alabastrine gypsum, and 6) rosettes of gypsum. Gypsum types 1 and 2 are interpreted as primary deposition in saline pans. Bottom-growth gypsum forms grass-like crusts while nodular/micronodular gypsum indicates displacive precipitation of the crust in shallow water and the groundwater capillary zone. Types 3 and 4 are early diagenetic precipitates. Abundant inclusions of tiny lath-like anhydrite crystals suggest a primary origin of anhydrite. Alabastrine gypsum, fibrous gypsum (satinspar) and rosettes of gypsum probably derived from near-surface hydration of anhydrite. The gypsum-bearing deposits in the Parnaíba Basin contribute towards understanding paleogeographic changes in Western Pangea. A progressive uplift of East Pangea, culminated in the forced regression and retreat of epicontinental seas to the West. Restricted seas or large lakes were formed before the definitive onset of desert conditions in Pangea, leading to the development of extensive ergs.

North Polar Gypsum Dunes in Olympia Undae

NASA Image and Video Library

2016-07-15

These sand dunes are a type of aeolian bedform and partly encircle the Martian North Pole in a region called Olympia Undae. Unlike most of the sand dunes on Mars that are made of the volcanic rock basalt, these are made of a type of sulfate mineral called gypsum. Whence the sand? Well, gypsum is a mineral that can often form from the evaporation of water that has sulfur and calcium dissolved in it. This sand was probably sourced from a northern region on Mars that used to be quite wet. The boxy gridding of the dunes indicates that the wind blows in multiple directions. Note: "Aeolian" means wind-blown and "bedform" means piles of sediment shaped by a flowing fluid (liquid or gas). http://photojournal.jpl.nasa.gov/catalog/PIA20743

Potential of a gypsum-free composting process of wheat straw for mushroom production

PubMed Central

Mouthier, Thibaut M. B.; Kilic, Baris; Vervoort, Pieter; Gruppen, Harry

2017-01-01

Wheat straw based composting generates a selective substrate for mushroom production. The first phase of this process requires 5 days, and a reduction in time is wished. Here, we aim at understanding the effect of gypsum on the duration of the first phase and the mechanism behind it. Hereto, the regular process with gypsum addition and the same process without gypsum were studied during a 5-day period. The compost quality was evaluated based on compost lignin composition analysed by py-GC/MS and its degradability by a commercial (hemi-)cellulolytic enzyme cocktail. The composting phase lead to the decrease of the pyrolysis products 4-vinylphenol and 4-vinylguaiacol that can be associated with p-coumarates and ferulates linking xylan and lignin. In the regular compost, the enzymatic conversion reached 32 and 39% for cellulose, and 23 and 32% for xylan after 3 and 5 days, respectively. In absence of gypsum similar values were reached after 2 and 4 days, respectively. Thus, our data show that in absence of gypsum the desired compost quality was reached 20% earlier compared to the control process. PMID:28982119

Primary Evaporites for the Messinian Salinity Crisis: the shallow gypsum vs. deep dolomite formation paradox solved

NASA Astrophysics Data System (ADS)

De Lange, Gert J.; Krijgsman, Wout

2014-05-01

The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, and resulted in the deposition of 0.3-3 km thick evaporites at the Mediterranean seafloor. A considerable and long-lasting controversy existed on the modes of their formation. During the CIESM Almeria Workshop a consensus was reached on several aspects. In addition, remaining issues to be solved were identified, such as for the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions. Gypsum precipitation only occurred at marginal settings, while dolomite containing rocks have been reported from deeper settings. A range of potential explanations have been reported, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are poorly understood and commonly neglected. These may, however, explain that different deposits formed in shallow versus deep environments without needing exceptional physical boundary conditions for each. We present here a unifying mechanism in which gypsum formation occurs at all shallow water depths but its preservation is mostly limited to shallow sedimentary settings. In contrast, ongoing anoxic organic matter (OM) degradation processes in the deep basin result in the formation of dolomite. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always largely oversaturated relative to dolomite but its formation is thought to be inhibited by the presence of dissolved sulphate. Thus the conditions for formation of gypsum exclude those for the formation of dolomite and vice versa. Another process that links the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, oxygen is rapidly depleted through OM degradation, then sulphate becomes the main oxidant for OM

Surface Coating of Gypsum-Based Molds for Maxillofacial Prosthetic Silicone Elastomeric Material: The Surface Topography.

PubMed

Khalaf, Salah; Ariffin, Zaihan; Husein, Adam; Reza, Fazal

2015-07-01

This study aimed to compare the surface roughness of maxillofacial silicone elastomers fabricated in noncoated and coated gypsum materials. This study was also conducted to characterize the silicone elastomer specimens after surfaces were modified. A gypsum mold was coated with clear acrylic spray. The coated mold was then used to produce modified silicone experimental specimens (n = 35). The surface roughness of the modified silicone elastomers was compared with that of the control specimens, which were prepared by conventional flasking methods (n = 35). An atomic force microscope (AFM) was used for surface roughness measurement of silicone elastomer (unmodified and modified), and a scanning electron microscope (SEM) was used to evaluate the topographic conditions of coated and noncoated gypsum and silicone elastomer specimens (unmodified and modified) groups. After the gypsum molds were characterized, the fabricated silicone elastomers molded on noncoated and coated gypsum materials were evaluated further. Energy-dispersive X-ray spectroscopy (EDX) analysis of gypsum materials (noncoated and coated) and silicone elastomer specimens (unmodified and modified) was performed to evaluate the elemental changes after coating was conducted. Independent t test was used to analyze the differences in the surface roughness of unmodified and modified silicone at a significance level of p < 0.05. Roughness was significantly reduced in the silicone elastomers processed against coated gypsum materials (p < 0.001). The AFM and SEM analysis results showed evident differences in surface smoothness. EDX data further revealed the presence of the desired chemical components on the surface layer of unmodified and modified silicone elastomers. Silicone elastomers with lower surface roughness of maxillofacial prostheses can be obtained simply by coating a gypsum mold. © 2014 by the American College of Prosthodontists.

Gypsum-permineralized microfossils and their relevance to the search for life on Mars.

PubMed

Schopf, J William; Farmer, Jack D; Foster, Ian S; Kudryavtsev, Anatoliy B; Gallardo, Victor A; Espinoza, Carola

2012-07-01

Orbital and in situ analyses establish that aerially extensive deposits of evaporitic sulfates, including gypsum, are present on the surface of Mars. Although comparable gypsiferous sediments on Earth have been largely ignored by paleontologists, we here report the finding of diverse fossil microscopic organisms permineralized in bottom-nucleated gypsums of seven deposits: two from the Permian (∼260 Ma) of New Mexico, USA; one from the Miocene (∼6 Ma) of Italy; and four from Recent lacustrine and saltern deposits of Australia, Mexico, and Peru. In addition to presenting the first report of the widespread occurrence of microscopic fossils in bottom-nucleated primary gypsum, we show the striking morphological similarity of the majority of the benthic filamentous fossils of these units to the microorganisms of a modern sulfuretum biocoenose. Based on such similarity, in morphology as well as habitat, these findings suggest that anaerobic sulfur-metabolizing microbial assemblages have changed relatively little over hundreds of millions of years. Their discovery as fossilized components of the seven gypsiferous units reported suggests that primary bottom-nucleated gypsum represents a promising target in the search for evidence of past life on Mars. Key Words: Confocal laser scanning microscopy-Gypsum fossils-Mars sample return missions-Raman spectroscopy-Sample Analysis at Mars (SAM) instrument-Sulfuretum.

Impact of FGD gypsum soil amendment applications on soil and environmental quality

USDA-ARS?s Scientific Manuscript database

This paper will discuss the utilization of FGD gypsum in agriculture for improving soil quality and other environmental benefits. Gypsum (CaSO4 .2H2O) has been used as an agricultural soil amendment for over 250 years. It is a soluble source of calcium and sulfur- for crops and has been shown to i...

Biosignatures in modern sulfates: texture, composition and depositional environments of gypsum deposits at Guerrero Negro, Baja, Mexico

NASA Astrophysics Data System (ADS)

Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Turk, K.; Kubo, M.

2007-12-01

Gypsum (CaSO4·H2O) is an important phase in biogeochemistry and sedimentology as a mineral sink for sulfur, a paleoclimatic indicator, and an endolithic niche for phototrophic and chemotrophic bacteria. Sulfate deposits are also important targets of exploration for evidence of habitable environments and life on Mars. Gypsum deposits from a range of sedimentary environments at the Guerrero Negro crystallizer ponds and sabkha settings were investigated for microscale structure and composition to differentiate fabrics formed under microbial influence from those formed under abiogenic conditions. Sub-sedimentary gypsum forms in sabkha environments as mm to cm scale selenite discs (termed bird beak gypsum; Warren, 2006) and selenite disc aggregates. Selenite discs and other sub-sedimentary gypsum are characterized by a sinuous axial microtexture and poikilitically enclosed detrital particles. Sub-aqueous gypsum forms as cements, granules (termed gypsooids), and massive botryoidal crusts that line the sediment water interface and margins of managed crystallizer ponds and natural anchialine pools. Sub-aqueous gypsum exhibits a wide range of textures and mineral/biofilm associations that include amorphous to euhedral, tabular, needle and lensoidal morphologies. Elemental sulfur forms rinds on prismatic, growth aligned gypsum twins and reticulate magnesian carbonate is interspersed with both twinned crystals and rosette aggregates in stratified sub-aqueous environments. Intracrystalline biofilms and cell material was observed in association with nearly all sub-aqueous morphologies but only scarce evidence has been found for intercrystalline microbial communities. Columnar microbial communities living in anchialine pools were found to host precipitation of mm scale gypsum granules in their EPS matrix. Fine scale gypsum textures are unlikely to persist through diagenetic alteration, but understanding their primary associations with sulfur and carbonates is necessary for

Can isotopic variations in structural water of gypsum reveal paleoclimatic changes?

NASA Astrophysics Data System (ADS)

Gatti, E.; Bustos, D.; Coleman, M. L.

2015-12-01

Water of crystallization in gypsum can be used as paleo-environmental proxy to study large scale climatic variability in arid areas. This is because changes in the isotopic composition of water of crystallization are due to isotopic variations in the mother brine from which the mineral precipitated, and the brine isotopic composition is linked to evaporation processes and humidity. This is particularly important when the salts are the only traces left of the original water, i.e. in modern arid areas. This study aims to prove that the 2-D/18-O compositions of the water of crystallization extracted from successive precipitates or even different growth zones of natural gypsum (CaSO4·H2O) can reconstruct the evaporation history and paleo-humidity of the source water basin. The method was tested in a laboratory experiment that evaporated CaSO4 brines under controlled temperature and humidity conditions. The brine was left to evaporate for five days at two different humidities (45 and 75 RH%); subsequently, brines and precipitated gypsum were sampled at 24 hour intervals. In this way we simulated zoned growth of gypsum. The samples were then analyzed for oxygen and hydrogen isotopic composition using a Thermo Scientific TC/EA with modified column, coupled to a MAT 253 Thermo Finnigan mass spectrometer at JPL. If preliminary results validate the novel hypothesis that changes in mineral composition can reveal details of paleo-environmental conditions the theory will be tested on natural gypsum collected from selected areas in White Sands National Monument, New Mexico. The study is currently ongoing but the full dataset will be presented at the conference.

Effect of gypsum application on mineral composition in peanut pod walls and seeds

USDA-ARS?s Scientific Manuscript database

Alleviation of soil-Ca deficiency through gypsum amendment increases the yield potential and ensures high seed quality in peanut (Arachis hypogaea L.). The effects of gypsum treatment, plant life cycle stage, and the fruit development stages on the accrual of several essential minerals (Ca, S, Mg, P...

Use of FGD gypsum on a bermudagrass pasture in the Appalachian Plateau Region

USDA-ARS?s Scientific Manuscript database

Addition of industrial by-products from coal fired power plants (FGD gypsum and FGD gypsum + fly ash) are thought to increase plant production. Thus, a study was conducted to evaluate the effects of industrial by-products as a soil amendment on bermudagrass (Cynodon dactylon L.) yield. The study was...

Crack Coalescence in Molded Gypsum and Carrara Marble

NASA Astrophysics Data System (ADS)

Wong, N.; Einstein, H. H.

2007-12-01

This research investigates the fracturing and coalescence behavior in prismatic laboratory-molded gypsum and Carrara marble specimens, which consist of either one or two pre-existing open flaws, under uniaxial compression. The tests are monitored by a high speed video system with a frame rate up to 24,000 frames/second. It allows one to precisely observe the cracking mechanisms, in particular if shear or tensile fracturing takes place. Seven crack types and nine crack coalescence categories are identified. The flaw inclination angle, the ligament length and the bridging angle between two flaws have different extents of influence on the coalescence patterns. For coplanar flaws, as the flaw inclination angle increases, there is a general trend of variation from shear coalescence to tensile coalescence. For stepped flaws, as the bridging angle changes from negative to small positive, and further up to large positive values, the coalescence generally progresses from categories of no coalescence, indirect coalescence to direct coalescence. For direct coalescence, it generally progresses from shear, mixed shear-tensile to tensile as the bridging angle increases. Some differences in fracturing and coalescence processes are observed in gypsum and marble, particularly the crack initiation in marble is preceded by the development of macroscopic white patches, but not in gypsum. Scanning Electron Microprobe (SEM) study reveals that the white patches consist of zones of microcracks (process zones).

Method Analysis of Microbial-Resistant Gypsum Products

EPA Science Inventory

Method Analysis of Microbial-Resistant Gypsum ProductsD.A. Betancourt1, T.R.Dean1, A. Evans2, and G.Byfield2 1. US Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory; RTP, NC 277112. RTI International, RTP, NCSeveral...

Gypsum Wallboard as a sink for formaldehyde

EPA Science Inventory

Formaldehyde (HCHO) has been of special concern as an indoor air pollutant because of its presence in a wide range of consumer products and its adverse health effects. Materials acting as HCHO sinks, such as painted gypsum wallboard, can become emission sources. However, adsorpti...

Gypsum treated fly ash as a liner for waste disposal facilities

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

Sivapullaiah, Puvvadi V., E-mail: siva@civil.iisc.ernet.in; Baig, M. Arif Ali, E-mail: reach2arif@gmail.com

2011-02-15

Fly ash has potential application in the construction of base liners for waste containment facilities. While most of the fly ashes improve in the strength with curing, the ranges of permeabilities they attain may often not meet the basic requirement of a liner material. An attempt has been made in the present context to reduce the hydraulic conductivity by adding lime content up to 10% to two selected samples of class F fly ashes. The use of gypsum, which is known to accelerate the unconfined compressive strength by increasing the lime reactivity, has been investigated in further improving the hydraulicmore » conductivity. Hydraulic conductivities of the compacted specimens have been determined in the laboratory using the falling head method. It has been observed that the addition of gypsum reduces the hydraulic conductivity of the lime treated fly ashes. The reduction in the hydraulic conductivity of the samples containing gypsum is significantly more for samples with high amounts of lime contents (as high as 1000 times) than those fly ashes with lower amounts of lime. However there is a relatively more increase in the strengths of the samples with the inclusion of gypsum to the fly ashes at lower lime contents. This is due to the fact that excess lime added to fly ash is not effectively converted into pozzolanic compounds. Even the presence of gypsum is observed not to activate these reactions with excess lime. On the other hand the higher amount of lime in the presence of sulphate is observed to produce more cementitious compounds which block the pores in the fly ash. The consequent reduction in the hydraulic conductivity of fly ash would be beneficial in reducing the leachability of trace elements present in the fly ash when used as a base liner.« less

Thermal analysis of calcium sulfate dihydrate sources used to manufacture gypsum wallboard

DOE PAGES

Engbrecht, Dick C.; Hirschfeld, Deidre A.

2016-07-27

Gypsum wallboard has been used for over 100 years as a barrier to the spread of fire in residential and commercial structures. The gypsum molecule, CaSO 4·2H 2O, provides two crystalline waters that are released upon heating providing an endothermic effect. Manufacturers have recognized that the source of the gypsum ore is a factor that affects all aspects of its performance; thus, it is hypothesized that the impurities present in the gypsum ore are the causes of the performance differences. Differential Thermal Analysis/Thermogravimetric Analysis (DTA/TGA) and X-ray Diffraction (XRD) were used in this paper to compare and characterize samples ofmore » gypsum ore representing sources of natural, synthetic from a Flue Gas Desulfurization process (FGD) and blends thereof. The hemihydrate phase of representative natural, FGD, and reagent grade calcium sulfate were rehydrated with distilled water and evaluated by DTA/TGA. Analysis of the data shows distinct areas of similarity separated by the conversion to anhydrite ~250 °C. Compositional reconstructions based on DTA/TGA and XRD data were compared and although, the results were comparable, the DTA/TGA suggests thermally active compounds that were not detected by XRD. Anhydrite, silica and halite were reported by XRD but were not thermally reactive in the temperature range evaluated by DTA/TGA (ambient to 1050 °C). Finally, the presence of carbonate compounds (e.g., calcite and dolomite) were indicated by XRD and estimated from the thermal decomposition reaction ~700 °C.« less

The origin of sulphur in gypsum and dissolved sulphate in the Central Namib Desert, Namibia

NASA Astrophysics Data System (ADS)

Eckardt, F. D.; Spiro, B.

1999-02-01

This study investigates the sulphur source of gypsum sulphate and dissolved groundwater sulphate in the Central Namib Desert, home to one of Africa's most extensive gypsum (CaSO 4·2H 2O) accumulations. It investigates previously suggested sulphate precursors such as bedrock sulphides and decompositional marine biogenic H 2S and studies the importance of other potential sources in order to determine the origin of gypsum and dissolved sulphate in the region. An attempt has been made to sample all possible sulphur sources, pathways and types of gypsum accumulations in the Central Namib Desert. We have subjected those samples to sulphur isotopic analyses and have compiled existing results. In addition, ionic ratios of Cl/SO 4 are used to determine the presence of non-sea-salt (NSS) sulphur in groundwater and to investigate processes affecting groundwater sulphate. In contrast to previous work, this study proposes that the sulphur cycle, and the formation of gypsum, in the Namib Desert appears to be dominated by the deposition of atmospheric sulphates of phytoplanktonic origin, part of the primary marine production of the Benguela upwelling cells. The aerosol sulphates are subjected to terrestrial storage within the gypsum deposits on the hyper-arid gravel plain and are traceable in groundwater including coastal sabkhas. The hypothesis of decompositional marine biogenic H 2S or bedrock sulphide sources, as considered previously for the Namib Desert, cannot account for the widespread accumulation of gypsum in the region. The study area in the Central Namib Desert, between the Kuiseb and Omaruru rivers, features extensive gypsum accumulations in a ca. 50-70 km wide band, parallel to the shore. They consist of surficial or shallow pedogenic gypsum crusts in the desert pavement, hydromorphic playa or sabkha gypsum, as thin isolated pockets on bedrock ridges and as discrete masses of gypsum selenite along some faults. The sulphur isotopic values (δ 34S ‰CDT) of these

[Study on microwave digestion of gypsum for the determination of multielement by ICP-OES and ICP-MS].

PubMed

Wang, Hui; Song, Qiang; Yang, Rui-ming; Yao, Qiang; Chen, Chang-he

2010-09-01

Three acids (HNO3, HNO3/HF and HNO3 /HF+ H3BO3) were used to decompose gypsum with microwave digestion system. The contents of 10 mineral elements (Al, Ca, Mg, Fe, K, Na, S, Ti, Si and Sr) in gypsum were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) while 6 heavy metals (V, Cr, Mn, Zn, Se and Ce) were determined by inductively coupled plasma-mass spectrometry (ICP-MS). GBW03109a, GBW03110 and FGD-2 were used as gypsum standard reference materials. The results showed that two-step microwave digestion with HNO3/HF at 210 degrees C and then adding H3BO3 for the removal of HF and fluorides completely decomposed the gypsums, while this method achieved good recoveries for all elements in the three gypsum standard reference materials. The recovery was from 88% to 112% and the RSD of tests was below 3%. The method was applied to the elemental analysis for flue gas desulfurization gypsums from three coal-fired power plants.

An important tool with no instruction manual: A review of gypsum use in agriculture

USDA-ARS?s Scientific Manuscript database

Land application of gypsum has been studied and utilized in agriculture and environmental remediation for many years. Most of the published literature has focused on gypsum application impacts on soil properties rather than crop yields. This literature review was conducted to (i) gather results from...

The Contributions Regarding the Use of Microwave to Obtain Modeling Gypsum for Phonic-Absorbent Construction and Orthopedic Materials

NASA Astrophysics Data System (ADS)

Pop, P. A.; Ungur, P. A.; Caraban, A.; Marcu, F.

2009-11-01

The paper has presented some experiments realized at "Congips" Co. Oradea and University of Oradea, regarding of increase machining efficiency and quality for modeling gypsum plaster by using of microwave energy to gypsum ore roast. The elaboration process of microwave energy for modeling gypsum plaster has done on electromagnetic waves properties and specific properties for dielectric materials. Microwaves are radiations of electromagnetic waveform nature, determine by pulsations of electrical-E) and magnetically-H components of electromagnetic wave in interdependence with Maxwell equations. The gypsum ore is calcium sulphate dehydrate (CaSO4ṡ2H2O) using at modeling gypsum plaster fabrication, which is calcium sulphate hemihydrate (CaSO4ṡ1/2H2O), that has behavior of dielectric with losses. The gypsum ore getting in microwave field, in conditions of predictable pressure and temperature has transformed in modeling gypsum plaster, by quick lost of a part from crystallization water. The processing time is very short, which due to a great productivity and machining efficiency, finally of low process cost. All of these recommend continuing the research at pilot station level.

Gypsum effects on crop yield and chemistry of soil, crop tissue, and vadose zone water: A meta-analysis.

USDA-ARS?s Scientific Manuscript database

Gypsum has various potential benefits as a soil amendment, but data are lacking on gypsum effects on crop yields and on environmental impacts across diverse field sites. Gypsum studies were conducted in six states using a common design with three rates each of mined and flue gas desulfurization (FGD...

Composite Gypsum Binders with Silica-containing Additives

NASA Astrophysics Data System (ADS)

Chernysheva, N. V.; Lesovik, V. S.; Drebezgova, M. Yu; Shatalova, S. V.; Alaskhanov, A. H.

2018-03-01

New types of fine mineral additives are proposed for designing water-resistant Composite Gypsum Binders (CGB); these additives significantly differ from traditional quartz feed: wastes from wet magnetic separation of Banded Iron Formation (BIF WMS waste), nanodispersed silica powder (NSP), chalk. Possibility of their combined use has been studied as well.

Experimental Shock Transformation of Gypsum to Anhydrite: A New Low Pressure Regime Shock Indicator

NASA Technical Reports Server (NTRS)

Bell, Mary S.; Zolensky, Michael E.

2011-01-01

The shock behavior of gypsum is important in understanding the Cretaceous/Paleogene event and other terrestrial impacts that contain evaporite sediments in their targets (e.g., Mars Exploration Rover Spirit detected sulfate at Gusev crater, [1]). Most interest focuses on issues of devolatilization to quantify the production of SO2 to better understand its role in generating a temporary atmosphere and its effects on climate and biota [2,3]. Kondo and Ahrens [4] measured induced radiation emitted from single crystal gypsum shocked to 30 and 40 GPa. They observed greybody emission spectra corresponding to temperatures in the range of 3,000 to 4,000 K that are a factor of 2 to 10 times greater than calculated pressure-density energy equation of state temperatures (Hugoniot) and are high enough to melt gypsum. Chen et al. [5] reported results of shock experiments on anhydrite, gypsum, and mixtures of these phases with silica. Their observations indicated little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another report of shock experiments on calcite, anhydrite, and gypsum, Badjukov et al. [6] observed only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa but have not experimentally shocked gypsum in a step-wise manner to constrain possible incipient transformation effects. Schmitt and Hornemann [7] shock loaded anhydrite and quartz to a peak pressure of 60 GPa and report the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggested that recrystallization of anhydrite grains is the result of a solid-state transformation. They concluded that significant decomposition of anhydrite requires shock pressures higher than 60 GPa. Gupta et al. [8

Gypsum's influence on corn yield and p loss from an eroded southern piedmont soil

USDA-ARS?s Scientific Manuscript database

Gypsum (CaSO4) has been shown to reduce dissolved P in surface water runoff from pastures fertilized with poultry litter (PL). However, limited research has evaluated gypsum’s influence on P loss under row crops. Moreover, can gypsum effectively reduce P loss when applied only to grass buffer strips...

Uranium minerals in Oligocene gypsum near Chadron, Dawes County, Nebraska

USGS Publications Warehouse

Dunham, R.J.

1955-01-01

Carnotite, sabugalite [HAI(UO2)4(PO4)4 • 16H2O] and autunite occur in the basal 25 feet of a 270-foot sequence of nonmarine bedded gypsum and gypsiferous clay in the Brule formation of Oligocene age about 12 miles northeast of Chadron in northeastern Dawes County, Nebraska. Uranium minerals are visible at only two localities and are associated with carbonaceous matter. Elsewhere the basal 25 feet of the gypsum sequence is interbedded with carbonate rocks and is weakly but persistently uraniferous. Uranium probably was emplaced from above by uranyl solutions rich in sulfate.

Compartmentalization of gypsum and halite associated with cyanobacteria in saline soil crusts.

PubMed

Canfora, Loredana; Vendramin, Elisa; Vittori Antisari, Livia; Lo Papa, Giuseppe; Dazzi, Carmelo; Benedetti, Anna; Iavazzo, Pietro; Adamo, Paola; Jungblut, Anne D; Pinzari, Flavia

2016-06-01

The interface between biological and geochemical components in the surface crust of a saline soil was investigated using X-ray diffraction, and variable pressure scanning electron microscopy in combination with energy dispersive X-ray spectrometry. Mineral compounds such as halite and gypsum were identified crystallized around filaments of cyanobacteria. A total of 92 genera were identified from the bacterial community based on 16S gene pyrosequencing analysis. The occurrence of the gypsum crystals, their shapes and compartmentalization suggested that they separated NaCl from the immediate microenvironment of the cyanobacteria, and that some cyanobacteria and communities of sulfur bacteria may had a physical control over the distinctive halite and gypsum structures produced. This suggests that cyanobacteria might directly or indirectly promote the formation of a protective envelope made of calcium and sulfur-based compounds. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Gypsum and organic matter distribution in a mixed construction and demolition waste sorting process and their possible removal from outputs.

PubMed

Montero, A; Tojo, Y; Matsuo, T; Matsuto, T; Yamada, M; Asakura, H; Ono, Y

2010-03-15

With insufficient source separation, construction and demolition (C&D) waste becomes a mixed material that is difficult to recycle. Treatment of mixed C&D waste generates residue that contains gypsum and organic matter and poses a risk of H(2)S formation in landfills. Therefore, removing gypsum and organic matter from the residue is vital. This study investigated the distribution of gypsum and organic matter in a sorting process. Heavy liquid separation was used to determine the density ranges in which gypsum and organic matter were most concentrated. The fine residue that was separated before shredding accounted for 27.9% of the waste mass and contained the greatest quantity of gypsum; therefore, most of the gypsum (52.4%) was distributed in this fraction. When this fine fraction was subjected to heavy liquid separation, 93% of the gypsum was concentrated in the density range of 1.59-2.28, which contained 24% of the total waste mass. Therefore, removing this density range after segregating fine particles should reduce the amount of gypsum sent to landfills. Organic matter tends to float as density increases; nevertheless, separation at 1.0 density could be more efficient. (c) 2009 Elsevier B.V. All rights reserved.

MOLD GROWTH ON GYPSUM WALLBOARD--A RESEARCH SUMMARY

EPA Science Inventory

Reducing occupant exposure to mold growing on damp gypsum wallboard is a research objective of the U.S. Environmental Protection Agency. Often mold contaminated building materials are not properly removed but instead surface cleaners are used and then paint is applied in an attem...

Evaluation of gypsum rates on greenhouse crop production

USDA-ARS?s Scientific Manuscript database

This study was to determine the potential of an added value distribution channel for gypsum waste by evaluating various greenhouse crops with captious pH and calcium needs. Three studies consisting of: Zonal geranium (Pelargonium x hortorum) and petunia (Petunia x hybrida); tomato (Solanum lycoper...

Impact of FGD gypsum application on trace elements

USDA-ARS?s Scientific Manuscript database

There are concerns regarding the fate of nutrients from surface application of animal waste. One approach to reduce losses of P is to treat manure with the industrial byproducts flue gas desulfurization gypsum (FGDG). However, concerns regarding heavy metal contributions to the environment have ar...

Building on previous OSL dating techniques for gypsum: a case study from Salt Basin playa, New Mexico and Texas

USGS Publications Warehouse

Mahan, Shannon; Kay, John

2012-01-01

The long term stability and reliability of the luminescence signal for gypsum has not been well documented or systematically measured until just recently. A review of the current literature for luminescence dating of gypsum is compiled here along with original efforts at dating an intact and in-situ bed of selenite gypsum at Salt Basin Playa, New Mexico and Texas. This effort differs from other documented luminescence dating efforts because the gypsum is not powdery or redistributed from its original growth patterns within the playa basin but is instead of a crystalline form. Sixteen ages from eight cores were ultimately produced with seven of the ages coming from rare detrital quartz encased in or with the gypsum crystals while the remaining ages are from the crystalline gypsum. As far as can be ascertained, the quartz was measured separately from the gypsum and no contaminants were noted in any of the aliquots. Some basic and preliminary tests of signal stability were measured and found to be mitigated by lessening of pre-heat protocols. Ages ranged from 8 ka to 10 ka in the shallow cores and 16 ka to 22 ka in the deeper cores. These ages will be useful in determining rates of gypsum growth within a sequence of evaporates which, in turn, will help to better document historic rates of evaporation and thus estimate, with more precision, the corresponding annual evaporation rates.

Accuracy of Gypsum Casts after Different Impression Techniques and Double Pouring

PubMed Central

Silva, Stephania Caroline Rodolfo; Messias, Aion Mangino; Abi-Rached, Filipe de Oliveira; de Souza, Raphael Freitas; Reis, José Maurício dos Santos Nunes

2016-01-01

This study evaluated the accuracy of gypsum casts after different impression techniques and double pouring. Ten patients were selected and for each one it was obtained 5 partial putty/wash impressions with vinyl polysiloxane (VPS) material from teeth #13 to #16 with partial metal stock trays. The following techniques were performed: (1) one-step; two-step relief with: (2) PVC film; (3) slow-speed tungsten carbide bur and scalpel blade, (4) small movements of the tray and (5) without relief—negative control. The impressions were disinfected with 0.5% sodium hypochlorite for 10 minutes and stored during 110 and 230 minutes for the first and second pouring, respectively, with type IV gypsum. Three intra-oral lateral photographs of each patient were taken using a tripod and a customized radiographic positioner. The images were imported into ImageJ software and the total area of the buccal surface from teeth #13 to #16 was measured. A 4.0% coefficient of variance was criterion for using these measurements as Baseline values. The casts were photographed and analyzed using the same standardization for the clinical images. The area (mm2) obtained from the difference between the measurements of each gypsum cast and the Baseline value of the respective patient were calculated and analyzed by repeated-measures two way-ANOVA and Mauchly’s Sphericity test (α = 0.05). No significant effect was observed for Impression technique (P = 0.23), Second pouring (P = 0.99) and their interaction (P = 0.25). The impression techniques and double pouring did not influence the accuracy of the gypsum casts. PMID:27736967

Accuracy of Gypsum Casts after Different Impression Techniques and Double Pouring.

PubMed

Silva, Stephania Caroline Rodolfo; Messias, Aion Mangino; Abi-Rached, Filipe de Oliveira; de Souza, Raphael Freitas; Reis, José Maurício Dos Santos Nunes

2016-01-01

This study evaluated the accuracy of gypsum casts after different impression techniques and double pouring. Ten patients were selected and for each one it was obtained 5 partial putty/wash impressions with vinyl polysiloxane (VPS) material from teeth #13 to #16 with partial metal stock trays. The following techniques were performed: (1) one-step; two-step relief with: (2) PVC film; (3) slow-speed tungsten carbide bur and scalpel blade, (4) small movements of the tray and (5) without relief-negative control. The impressions were disinfected with 0.5% sodium hypochlorite for 10 minutes and stored during 110 and 230 minutes for the first and second pouring, respectively, with type IV gypsum. Three intra-oral lateral photographs of each patient were taken using a tripod and a customized radiographic positioner. The images were imported into ImageJ software and the total area of the buccal surface from teeth #13 to #16 was measured. A 4.0% coefficient of variance was criterion for using these measurements as Baseline values. The casts were photographed and analyzed using the same standardization for the clinical images. The area (mm2) obtained from the difference between the measurements of each gypsum cast and the Baseline value of the respective patient were calculated and analyzed by repeated-measures two way-ANOVA and Mauchly's Sphericity test (α = 0.05). No significant effect was observed for Impression technique (P = 0.23), Second pouring (P = 0.99) and their interaction (P = 0.25). The impression techniques and double pouring did not influence the accuracy of the gypsum casts.

Controlled study of mold growth and cleaning procedure on treated and untreated wet gypsum wallboard in an indoor environment.

PubMed

Krause, Michael; Geer, William; Swenson, Lonie; Fallah, Payam; Robbins, Coreen

2006-08-01

The basis for some common gypsum wallboard mold remediation practices was examined. The bottom inch of several gypsum wallboard panels was immersed in bottled drinking water; some panels were coated and others were untreated. The panels were examined and tested for a period of 8 weeks. This study investigated: (a) whether mold growth, detectable visually or with tape lift samples, occurs within 1 week on wet gypsum wallboard; (b) the types, timing, and extent of mold growth on wet gypsum wallboard; (c) whether mold growth is present on gypsum wallboard surfaces 6 inches from visible mold growth; (d) whether some commonly used surface treatments affect the timing of occurrence and rate of mold growth; and (e) if moldy but dried gypsum wallboard can be cleaned with simple methods and then sealed with common surface treatments so that residual mold particles are undetectable with typical surface sampling techniques. Mold growth was not detected visually or with tape lift samples after 1 week on any of the wallboard panels, regardless of treatment, well beyond the 24-48 hours often mentioned as the incubation period. Growth was detected at 2 weeks on untreated gypsum. Penicillium, Cladosporium, and Acremonium were early colonizers of untreated panels. Aspergillus, Epicoccum, Alternaria, and Ulocladium appeared later. Stachybotrys was not found. Mold growth was not detected more than 6 inches beyond the margin of visible mold growth, suggesting that recommendations to remove gypsum wallboard more than 1 foot beyond visible mold are excessive. The surface treatments resulted in delayed mold growth and reduced the area of mold growth compared with untreated gypsum wallboard. Results showed that simple cleaning of moldy gypsum wallboard was possible to the extent that mold particles beyond "normal trapping" were not found on tape lift samples. Thus, cleaning is an option in some situations where removal is not feasible or desirable. In cases where conditions are not

Jefferson Proving Ground, South of the Firing Line, Final Asbestos Survey Summary Report. Volume 3. Buildings 230 through 475

DTIC Science & Technology

1993-09-01

interior is finished with plaster or wallboard (i.e., sheetrock, drywall, gypsum board , etc.) walls and ceilings, "cheese-cloth" wall and ceiling lining...with wallboard (i.e., sheetrock, drywall, gypsum board , etc.) walls and ceilings, acoustical ceiling panels/tiles, and vinyl tile or bare concrete...finished with wallboard (i.e., sheetrock, drywall, gypsum board , etc.) walls and ceilings, and vinyl tile or bare concrete floors. "* No fireproofing or

Gypsum-wallboard formaldehyde-sorption model

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

Silberstein, S.

1989-11-01

Gypsum wallboard was shown to absorb formaldehyde in a prototype house and in a measuring chamber, as reported previously by researchers at Oak Ridge National Laboratory (ORNL). Also as reported previously, formaldehyde concentrations attained equilibrium in two phases in response to a change in the air exchange rate or to the removal of the formaldehyde source. A rapid initial phase was followed by a slow phase lasting several days. A formaldehyde sorption model that accounts for the biphasic concentration pattern is presented here. Experiments for testing the predictability of the model are proposed.

Effect of amino acids on the precipitation kinetics and Ca isotopic composition of gypsum

NASA Astrophysics Data System (ADS)

Harouaka, Khadouja; Kubicki, James D.; Fantle, Matthew S.

2017-12-01

Stirred gypsum (CaSO4 · 2H2O) precipitation experiments (initial Ωgypsum = 2.4 ± 0.14, duration ≈ 1.0-1.5 h) were conducted in the presence of the amino acids glycine (190 μM), L-alanine (190 μM), D- and L-arginine (45 μM), and L-tyrosine (200 μM) to investigate the effect of simple organic compounds on both the precipitation kinetics and Ca isotopic composition of gypsum. Relative to abiotic controls, glycine, tyrosine, and alanine inhibited precipitation rates by ∼22%, 27%, and 29%, respectively, while L- and D-arginine accelerated crystal growth by ∼8% and 48%, respectively. With the exception of tyrosine, amino acid induced inhibition resulted in fractionation factors (αs-f) associated with precipitation that were no more than 0.3‰ lower than amino acid-free controls. In contrast, the tyrosine and D- and L-arginine experiments had αs-f values associated with precipitation that were similar to the controls. Our experimental results indicate that Ca isotopic fractionation associated with gypsum precipitation is impacted by growth inhibition in the presence of amino acids. Specifically, we propose that the surface-specific binding of amino acids to gypsum can change the equilibrium fractionation factor of the bulk mineral. We investigate the hypothesis that amino acids can influence the growth of gypsum at specific crystal faces via adsorption and that different faces have distinct fractionation factors (αface-fluid). Accordingly, preferential sorption of amino acids at particular faces changes the relative, face-specific mass fluxes of Ca during growth, which influences the bulk isotopic composition of the mineral. Density functional theory (DFT) calculations suggest that the energetic favorability of glycine sorption onto gypsum crystal faces occurs in the order: (1 1 0) > (0 1 0) > (1 2 0) > (0 1 1), while glycine sorption onto the (-1 1 1) face was found to be energetically unfavorable. Face-specific fractionation factors constrained by

EXPOSE-R2: The Astrobiological ESA Mission on Board of the International Space Station.

PubMed

Rabbow, Elke; Rettberg, Petra; Parpart, Andre; Panitz, Corinna; Schulte, Wolfgang; Molter, Ferdinand; Jaramillo, Esther; Demets, René; Weiß, Peter; Willnecker, Rainer

2017-01-01

On July 23, 2014, the Progress cargo spacecraft 56P was launched from Baikonur to the International Space Station (ISS), carrying EXPOSE-R2, the third ESA (European Space Agency) EXPOSE facility, the second EXPOSE on the outside platform of the Russian Zvezda module, with four international astrobiological experiments into space. More than 600 biological samples of archaea, bacteria (as biofilms and in planktonic form), lichens, fungi, plant seeds, triops eggs, mosses and 150 samples of organic compounds were exposed to the harsh space environment and to parameters similar to those on the Mars surface. Radiation dosimeters distributed over the whole facility complemented the scientific payload. Three extravehicular activities later the chemical samples were returned to Earth on March 2, 2016, with Soyuz 44S, having spent 588 days in space. The biological samples arrived back later, on June 18, 2016, with 45S, after a total duration in space of 531 days. The exposure of the samples to Low Earth Orbit vacuum lasted for 531 days and was divided in two parts: protected against solar irradiation during the first 62 days, followed by exposure to solar radiation during the subsequent 469 days. In parallel to the space mission, a Mission Ground Reference (MGR) experiment with a flight identical Hardware and a complete flight identical set of samples was performed at the premises of DLR (German Aerospace Center) in Cologne by MUSC (Microgravity User Support Center), according to the mission data either downloaded from the ISS (temperature data, facility status, inner pressure status) or provided by RedShift Design and Engineering BVBA, Belgium (calculated ultra violet radiation fluence data). In this paper, the EXPOSE-R2 facility, the experimental samples, mission parameters, environmental parameters, and the overall mission and MGR sequences are described, building the background for the research papers of the individual experiments, their analysis and results.

EXPOSE-R2: The Astrobiological ESA Mission on Board of the International Space Station

PubMed Central

Rabbow, Elke; Rettberg, Petra; Parpart, Andre; Panitz, Corinna; Schulte, Wolfgang; Molter, Ferdinand; Jaramillo, Esther; Demets, René; Weiß, Peter; Willnecker, Rainer

2017-01-01

On July 23, 2014, the Progress cargo spacecraft 56P was launched from Baikonur to the International Space Station (ISS), carrying EXPOSE-R2, the third ESA (European Space Agency) EXPOSE facility, the second EXPOSE on the outside platform of the Russian Zvezda module, with four international astrobiological experiments into space. More than 600 biological samples of archaea, bacteria (as biofilms and in planktonic form), lichens, fungi, plant seeds, triops eggs, mosses and 150 samples of organic compounds were exposed to the harsh space environment and to parameters similar to those on the Mars surface. Radiation dosimeters distributed over the whole facility complemented the scientific payload. Three extravehicular activities later the chemical samples were returned to Earth on March 2, 2016, with Soyuz 44S, having spent 588 days in space. The biological samples arrived back later, on June 18, 2016, with 45S, after a total duration in space of 531 days. The exposure of the samples to Low Earth Orbit vacuum lasted for 531 days and was divided in two parts: protected against solar irradiation during the first 62 days, followed by exposure to solar radiation during the subsequent 469 days. In parallel to the space mission, a Mission Ground Reference (MGR) experiment with a flight identical Hardware and a complete flight identical set of samples was performed at the premises of DLR (German Aerospace Center) in Cologne by MUSC (Microgravity User Support Center), according to the mission data either downloaded from the ISS (temperature data, facility status, inner pressure status) or provided by RedShift Design and Engineering BVBA, Belgium (calculated ultra violet radiation fluence data). In this paper, the EXPOSE-R2 facility, the experimental samples, mission parameters, environmental parameters, and the overall mission and MGR sequences are described, building the background for the research papers of the individual experiments, their analysis and results. PMID

10. INTERIOR VIEW OF ROOM 110, LOOKING NORTHWEST FROM THE ...

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

10. INTERIOR VIEW OF ROOM 110, LOOKING NORTHWEST FROM THE EAST CORNER. SPACE IS DIVIDED BY EXPOSED POSTS AND BEAMS DESIGNATING ANIMALS QUARTERS AND AISLES. FLOORS ARE WOOD PLANKS IN ANIMAL AREAS CHANGING TO CONCRETE IN CENTER AISLES. CEILING IS GYPSUM BOARD. - Presidio of San Francisco, Cavalry Stables, Cowles Street, between Lincoln Boulevard & McDowell Street, San Francisco, San Francisco County, CA

Dimensional accuracy and surface property of titanium casting using gypsum-bonded alumina investment.

PubMed

Yan, Min; Takahashi, Hidekazu; Nishimura, Fumio

2004-12-01

The aim of the present study was to evaluate the dimensional accuracy and surface property of titanium casting obtained using a gypsum-bonded alumina investment. The experimental gypsum-bonded alumina investment with 20 mass% gypsum content mixed with 2 mass% potassium sulfate was used for five cp titanium castings and three Cu-Zn alloy castings. The accuracy, surface roughness (Ra), and reaction layer thickness of these castings were investigated. The accuracy of the castings obtained from the experimental investment ranged from -0.04 to 0.23%, while surface roughness (Ra) ranged from 7.6 to 10.3microm. A reaction layer of about 150 microm thickness under the titanium casting surface was observed. These results suggested that the titanium casting obtained using the experimental investment was acceptable. Although the reaction layer was thin, surface roughness should be improved.

Investigation on the Permeability Evolution of Gypsum Interlayer Under High Temperature and Triaxial Pressure

NASA Astrophysics Data System (ADS)

Tao, Meng; Yechao, You; Jie, Chen; Yaoqing, Hu

2017-08-01

The permeability of the surrounding rock is a critical parameter for the designing and assessment of radioactive waste disposal repositories in the rock salt. Generally, in the locations that are chosen for radioactive waste storage, the bedded rock salt is a sedimentary rock that contains NaCl and Na2SO4. Most likely, there are also layers of gypsum ( {CaSO}_{ 4} \\cdot 2 {H}_{ 2} {O)} present in the salt deposit. Radioactive wastes emit a large amount of heat and hydrogen during the process of disposal, which may result in thermal damage of the surrounding rocks and cause a great change in their permeability and tightness. Therefore, it is necessary to investigate the permeability evolution of the gypsum interlayer under high temperature and high pressure in order to evaluate the tightness and security of the nuclear waste repositories in bedded rock salt. In this study, a self-designed rock triaxial testing system by which high temperature and pressure can be applied is used; the μCT225kVFCB micro-CT system is also employed to investigate the permeability and microstructure of gypsum specimens under a constant hydrostatic pressure of 25 MPa, an increasing temperature (ranging from 20 to 650 °C), and a variable inlet gas pressure (1, 2, 4, 6 MPa). The experimental results show: (a) the maximum permeability measured during the whole experiment is less than 10-17 m2, which indicates that the gypsum interlayer has low permeability under high temperature and pressure that meet the requirements for radioactive waste repository. (b) Under the same temperature, the permeability of the gypsum specimen decreases at the beginning and then increases as the pore pressure elevates. When the inlet gas pressure is between 0 and 2 MPa, the Klinkenberg effect is very pronounced. Then, as the pore pressure increases, the movement behavior of gas molecules gradually changes from free motion to forced directional motion. So the role of free movement of gas molecules gradually

Competition between reaction-induced expansion and creep compaction during gypsum formation: Experimental and numerical investigation

NASA Astrophysics Data System (ADS)

Skarbek, R. M.; Savage, H. M.; Spiegelman, M. W.; Kelemen, P. B.; Yancopoulos, D.

2017-12-01

Deformation and cracking caused by reaction-driven volume increase is an important process in many geological settings, however the conditions controlling these processes are poorly understood. The interaction of rocks with reactive fluids can change permeability and reactive surface area, leading to a large variety of feedbacks. Gypsum is an ideal material to study these processes. It forms rapidly at room temperature via bassanite hydration, and is commonly used as an analogue for rocks in high-temperature, high-pressure conditions. We conducted uniaxial strain experiments to study the effects of applied axial load on deformation and fluid flow during the formation of gypsum from bassanite. While hydration of bassanite to gypsum involves a solid volume increase, gypsum exhibits significant creep compaction when in contact with water. These two volume changing processes occur simultaneously during fluid flow through bassanite. We cold-pressed bassanite powder to form cylinders 2.5 cm in height and 1.2 cm in diameter. Samples were compressed with a static axial load of 0.01 to 4 MPa. Water infiltrated initially unsaturated samples through the bottom face and the height of the samples was recorded as a measure of the total volume change. We also performed experiments on pure gypsum samples to constrain the amount of creep observed in tests on bassanite hydration. At axial loads < 0.15 MPa, volume increase due to the reaction dominates and samples exhibit monotonic expansion. At loads > 1 MPa, creep in the gypsum dominates and samples exhibit monotonic compaction. At intermediate loads, samples exhibit alternating phases of compaction and expansion due to the interplay of the two volume changing processes. We observed a change from net compaction to net expansion at an axial load of 0.250 MPa. We explain this behavior with a simple model that predicts the strain evolution, but does not take fluid flow into account. We also implement a 1D poro-visco-elastic model of

Constraining the origin of the Messinian gypsum deposits using coupled measurement of δ^{18}O$/δD in gypsum hydration water and salinity of fluid inclusions

NASA Astrophysics Data System (ADS)

Evans, Nicholas P.; Gázquez, Fernando; McKenzie, Judith A.; Chapman, Hazel J.; Hodell, David A.

2016-04-01

We used oxygen and hydrogen isotopes of gypsum hydration water (GHW) coupled with salinity deduced from ice melting temperatures of primary fluid inclusions in the same samples (in tandem with 87Sr/86Sr, δ34S and other isotopic measurements) to determine the composition of the mother fluids that formed the gypsum deposits of the Messinian Salinity Crisis from shallow and intermediate-depth basins. Using this method, we constrain the origin of the Messinian Primary Lower Gypsum (PLG) of the Sorbas basin (Betic foreland) and both the Upper Gypsum (UG) and the Lower Gypsum of the Sicilian basin. We then compare these results to measurements made on UG recovered from the deep Ionian and Balearic basins drilled during DSDP Leg 42A. The evolution of GHW δ18O/δD vs. salinity is controlled by mixing processes between fresh and seawater, coupled with the degree of evaporation. Evaporation and subsequent precipitation of gypsum from fluids dominated by freshwater will result in a depressed 87Sr/86Sr values and different trajectory in δ18O/δD vs. salinity space compared to fluids dominated by seawater. The slopes of these regression equations help to define the end-members from which the fluid originated. For example, salinity estimates from PLG cycle 6 in the Sorbas basin range from 18 to 51ppt, and after correction for fractionation factors, estimated δ18O and δD values of the mother water are low (-2.6 < δ18O < 2.7‰ ; -16.2 < δD < 15.8‰). The intercepts of the regression equations (i.e. at zero salinity) are within error of the average isotope composition of the modern precipitation and groundwater in this region of SE Spain. This indicates there was a significant contribution of meteoric water during gypsum deposition, while 87Sr/86Sr (0.708942 < 87Sr/86Sr < 0.708971) indicate the ions originated from the dissolution of previously marine evaporites. Gypsum from cycle 2 displays similar mother water values (-2.4 < δ18O < 2.4‰ ; -13.2 < δD < 17.0‰) to

Window contamination on Expose-R

NASA Astrophysics Data System (ADS)

Demets, R.; Bertrand, M.; Bolkhovitinov, A.; Bryson, K.; Colas, C.; Cottin, H.; Dettmann, J.; Ehrenfreund, P.; Elsaesser, A.; Jaramillo, E.; Lebert, M.; van Papendrecht, G.; Pereira, C.; Rohr, T.; Saiagh, K.

2015-01-01

Expose is a multi-user instrument for astrobiological and astrochemical experiments in space. Installed at the outer surface of the International Space Station, it enables investigators to study the impact of the open space environment on biological and biochemical test samples. Two Expose missions have been completed so far, designated as Expose-E (Rabbow et al. 2012) and Expose-R (Rabbow et al. this issue). One of the space-unique environmental factors offered by Expose is full-spectrum, ultraviolet (UV)-rich electromagnetic radiation from the Sun. This paper describes and analyses how on Expose-R, access of the test samples to Solar radiation degraded during space exposure in an unpredicted way. Several windows in front of the Sun-exposed test samples acquired a brown shade, resulting in a reduced transparency in visible light, UV and vacuum UV (VUV). Post-flight investigations revealed the discolouration to be caused by a homogenous film of cross-linked organic polymers at the inside of the windows. The chemical signature varied per sample carrier. No such films were found on windows from sealed, pressurized compartments, or on windows that had been kept out of the Sun. This suggests that volatile compounds originating from the interior of the Expose facility were cross-linked and photo-fixed by Solar irradiation at the rear side of the windows. The origin of the volatiles was not fully identified; most probably there was a variety of sources involved including the biological test samples, adhesives, plastics and printed circuit boards. The outer surface of the windows (pointing into space) was chemically impacted as well, with a probable effect on the transparency in VUV. The reported analysis of the window contamination on Expose-R is expected to help the interpretation of the scientific results and offers possibilities to mitigate this problem on future missions - in particular Expose-R2, the direct successor of Expose-R.

Biological influences on modern sulfates: Textures and composition of gypsum deposits from Guerrero Negro, Baja California Sur, Mexico

NASA Astrophysics Data System (ADS)

Vogel, Marilyn B.; Des Marais, David J.; Parenteau, Mary N.; Jahnke, Linda L.; Turk, Kendra A.; Kubo, Michael D. Y.

2010-01-01

Gypsum (CaSO 4·2H 2O) deposits from a range of sedimentary environments at Guerrero Negro, Baja California Sur, Mexico were investigated for microscale texture and composition in order to differentiate features formed under substantial microbial influence from those for which microbial effects were relatively minor or absent. Gypsum deposits were classified according to their sedimentary environment, textures, crystal habit, brine composition and other geochemical factors. The environments studied included subaqueous sediments in anchialine pools and in solar salterns, as well as subsurface sediments of mudflats and saltpans. Gypsum that developed in the apparent absence of biofilms included crystals precipitated in the water column and subsedimentary discs that precipitated from phreatic brines. Subsedimentary gypsum developed in sabkha environments exhibited a sinuous microtexture and poikilitically enclosed detrital particles. Water column precipitates had euhedral prismatic habits and extensive penetrative twinning. Gypsum deposits influenced by biofilms included bottom nucleated crusts and gypsolites developing in anchialine pools and saltern ponds. Gypsum precipitating within benthic biofilms, and in biofilms within subaerial sediment surfaces provided compelling evidence of biological influences on crystal textures and habits. This evidence included irregular, high relief surface textures, accessory minerals (S°, Ca-carbonate, Sr/Ca-sulfate and Mg-hydroxide) and distinctive crystal habits such as equant forms and crystals having distorted prism faces.

Testing antimicrobial paint efficacy on gypsum wallboard contaminated with Stachybotrys chartarum.

PubMed

Menetrez, M Y; Foarde, K K; Webber, T D; Dean, T R; Betancourt, D A

2008-02-01

The goal of this research was to reduce occupant exposure to indoor mold through the efficacy testing of antimicrobial paints. An accepted method for handling Stachybotrys chartarum-contaminated gypsum wallboard (GWB) is removal and replacement. This practice is also recommended for water-damaged or mold-contaminated GWB but is not always followed completely. The efficacy of antimicrobial paints to eliminate or control mold regrowth on surfaces can be tested easily on nonporous surfaces. The testing of antimicrobial efficacy on porous surfaces found in the indoor environment, such as gypsum wallboard, can be more complicated and prone to incorrect conclusions regarding residual organisms. The mold S. chartarum has been studied for toxin production and its occurrence in water-damaged buildings. Research to control its growth using seven different antimicrobial paints and two commonly used paints on contaminated, common gypsum wallboard was performed in laboratory testing at high relative humidity. The results indicate differences in antimicrobial efficacy for the period of testing, and that proper cleaning and resurfacing of GWB with an antimicrobial paint can be an option in those unique circumstances when removal may not be possible.

Testing CO2 Sequestration in an Alkaline Soil Treated with Flue Gas Desulfurization Gypsum (FGDG)

NASA Astrophysics Data System (ADS)

Han, Y.; Tokunaga, T. K.

2012-12-01

Identifying effective and economical methods for increasing carbon storage in soils is of interest for reducing soil CO2 fluxes to the atmosphere in order to partially offset anthropogenic CO2 contributions to climate change This study investigates an alternative strategy for increasing carbon retention in soils by accelerating calcite (CaCO3) precipitation and promoting soil organic carbon (SOC) complexation on mineral surfaces. The addition of calcium ion to soils with pH > 8, often found in arid and semi-arid regions, may accelerate the slow process of calcite precipitation. Increased ionic strength from addition of a soluble Ca source also suppresses microbial activity which oxidizes SOC to gaseous CO2. Through obtaining C mass balances in soil profiles, this study is quantifying the efficiency of gypsum amendments for mitigating C losses to the atmosphere. The objective of this study is to identify conditions in which inorganic and organic C sequestration is practical in semi-arid and arid soils by gypsum treatment. As an inexpensive calcium source, we proposed to use flue gas desulfurization gypsum (FGDG), a byproduct of fossil fuel burning electric power plants. To test the hypothesis, laboratory column experiments have been conducted in calcite-buffered soil with addition of gypsum and FGDG. The results of several months of column monitoring are demonstrating that gypsum-treated soil have lowered amounts of soil organic carbon loss and increased inorganic carbon (calcite) production. The excess generation of FGDG relative to industrial and agricultural needs, FGDG, is currently regarded as waste. Thus application of FGDG application in some soils may be an effective and economical means for fixing CO2 in soil organic and inorganic carbon forms.Soil carbon cycle, with proposed increased C retention by calcite precipitation and by SOC binding onto soil mineral surfaces, with both processes driven by calcium released from gypsum dissolution.

Petroleum Sludge as gypsum replacement in cement plants: Its Impact on Cement Strength

NASA Astrophysics Data System (ADS)

Benlamoudi, Ali; Kadir, Aeslina Abdul; Khodja, Mohamed

2017-08-01

Due to high cost of cement manufacturing and the huge amount of resources exhaustion, companies are trying to incorporate alternative raw materials or by-products into cement production so as to produce alternative sustainable cement. Petroleum sludge is a dangerous waste that poses serious imparts on soil and groundwater. Given that this sludge contains a high percentage of anhydrite (CaSO4), which is the main component of gypsum (CaSO4.2H2O), it may play the same gypsum role in strength development. In this research, a total replacement of gypsum (100%) has been substituted by petroleum sludge in cement production and has led to an increase of 28.8% in UCS values after 28 curing days. Nevertheless, the burning of this waste has emitted a considerable amount of carbon monoxide (CO) gas that needs to be carefully considered prior to use petroleum sludge within cement plants.

Why does carbon increase in highly weathered soil under no-till upon lime and gypsum use?

PubMed

Inagaki, Thiago Massao; de Moraes Sá, João Carlos; Caires, Eduardo Fávero; Gonçalves, Daniel Ruiz Potma

2017-12-01

Field experiments have been used to explain how soil organic carbon (SOC) dynamics is affected by lime and gypsum applications, however, how SOC storage occurs is still debatable. We hypothesized that although many studies conclude that Ca-based soil amendments such as lime and gypsum may lead to SOC depletion due to the enhancement of microbial activity, the same does not occur under conservation agriculture conditions. Thus, the objective of this study was to elucidate the effects of lime and gypsum applications on soil microbial activity and SOC stocks in a no-till field and in a laboratory incubation study simulating no-till conditions. The field experiment was established in 1998 in a clayey Oxisol in southern Brazil following a completely randomized blocks design with a split-plot arrangement and three replications. Lime and gypsum were surface applied in 1998 and reapplied in 2013. Undisturbed soil samples were collected before the treatments reapplications, and one year after. The incubation experiment was carried out during 16months using these samples adding crop residues on the soil surface to simulate no-till field conditions. Lime and gypsum applications significantly increased the labile SOC stocks, microbial activity and soil fertility attributes in both field and laboratory experiments. Although the microbial activity was increased, no depletion of SOC stocks was observed in both experiments. Positive correlations were observed between microbial activity increase and SOC gains. Labile SOC and Ca 2+ content increase leads to forming complex with mineral soil fractions. Gypsum applications performed a higher influence on labile SOC pools in the field than in the laboratory experiment, which may be related to the presence of active root system in the soil profile. We conclude that incubation experiments using lime and gypsum in undisturbed samples confirm that soil microbial activity increase does not deplete SOC stocks under conservation agriculture

In Situ Observation of Gypsum-Anhydrite Transition at High Pressure and High Temperature

NASA Astrophysics Data System (ADS)

Liu, Chuan-Jiang; Zheng, Hai-Fei

2012-04-01

An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC). The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa. With increasing temperature, the anhydrite (CaSO4) phase precipitates at 250-320°C in the pressure range of 1.0-1.5GPa, indicating that under a saturated water condition, both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite. A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) = 0.0068T-0.7126 (250°C<=T<=320°C). Anhydrite remained stable during rapid cooling of the sample chamber, showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature.

Light in the darkening on Naica gypsum crystals

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

Castillo-Sandoval, I.; Fuentes-Cobas, L. E.; Esparza-Ponce, H. E.

2015-07-23

Naica mine is located in a semi-desertic region at the central-south of Chihuahua State. The Cave of Swords was discovered in 1910 and the Cave of Crystals 90 years later at Naica mines. It is expected that during the last century the human presence has changed the microclimatic conditions inside the cave, resulting in the deterioration of the crystals and the deposition of impurities on gypsum surfaces. As a contribution to the clarification of the mentioned issues, the present work refers to the use of synchrotron radiation for the identification of phases on these surfaces. All the experiments were performedmore » at the Stanford Synchrotron Radiation Lightsource. Grazing incidence X-ray diffraction (GIXRD) and radiography-aided X-ray diffraction (RAXRD) experiments were performed at beamline 11-3. X-Ray micro-fluorescence (μ-SXRF) and micro-X-ray absorption (μ-XANES) were measured at beamline 2-3. Representative results obtained may be summarized as follows: a) Gypsum, galena, sphalerite, hematite and cuprite at the surface of the gypsum crystals were determined. b) The samples micro-structure is affected by impurities. c) The elemental distributions and correlations (0.6-0.9) of Cu, K, Fe, Mn, Pb, Zn, Ca and S were identified by μ-SXRF. The correlations among elemental contents confirmed the phase identification, with the exception of manganese and potassium due to the amorphous nature of some impurity compounds in these samples. The compounds hematite (Fe{sub 2}O{sub 3}), β-MnO{sub 2}, Mn{sub 2}O{sub 3}, MnO and/or MnCO{sub 3}, PbS, PbCO{sub 3} and/or PbSO4, ZnO{sub 4}, ZnS and/or smithsonite (ZnCO{sub 3}), CuS + Cu Oxide were identified by XANES. Plausibly, these latter compounds do not form crystalline phases.« less

Light in the darkening on Naica gypsum crystals

NASA Astrophysics Data System (ADS)

Castillo-Sandoval, I.; Fuentes-Cobas, L. E.; Fuentes-Montero, M. E.; Esparza-Ponce, H. E.; Carreno-Márquez, J.; Reyes-Cortes, M.; Montero-Cabrera, M. E.

2015-07-01

Naica mine is located in a semi-desertic region at the central-south of Chihuahua State. The Cave of Swords was discovered in 1910 and the Cave of Crystals 90 years later at Naica mines. It is expected that during the last century the human presence has changed the microclimatic conditions inside the cave, resulting in the deterioration of the crystals and the deposition of impurities on gypsum surfaces. As a contribution to the clarification of the mentioned issues, the present work refers to the use of synchrotron radiation for the identification of phases on these surfaces. All the experiments were performed at the Stanford Synchrotron Radiation Lightsource. Grazing incidence X-ray diffraction (GIXRD) and radiography-aided X-ray diffraction (RAXRD) experiments were performed at beamline 11-3. X-Ray micro-fluorescence (μ-SXRF) and micro-X-ray absorption (μ-XANES) were measured at beamline 2-3. Representative results obtained may be summarized as follows: a) Gypsum, galena, sphalerite, hematite and cuprite at the surface of the gypsum crystals were determined. b) The samples micro-structure is affected by impurities. c) The elemental distributions and correlations (0.6-0.9) of Cu, K, Fe, Mn, Pb, Zn, Ca and S were identified by μ-SXRF. The correlations among elemental contents confirmed the phase identification, with the exception of manganese and potassium due to the amorphous nature of some impurity compounds in these samples. The compounds hematite (Fe2O3), β-MnO2, Mn2O3, MnO and/or MnCO3, PbS, PbCO3 and/or PbSO4, ZnO4, ZnS and/or smithsonite (ZnCO3), CuS + Cu Oxide were identified by XANES. Plausibly, these latter compounds do not form crystalline phases.

Stratigraphy and depositional environments of Jurassic Gypsum Spring and Sundance Formations, Sheep Mountain anticline area, Big Horn County, Wyoming

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

Doyle, A.B.

1986-08-01

The Sheep Mountain anticlinal complex between Lovell and Greybull, Wyoming, in the Bighorn basin provides exposure suitable for three-dimensional stratigraphic studies of Mesozoic rocks. The lower unit of the Gypsum Spring Formation is interbedded shale and gypsum. The middle unit is a cyclic sequence of variegated shales, mudstones, and wackestones. The upper unit is red shale. The contact between the underlying Upper Triassic Chugwater Group and the Gypsum Spring Formation is unconformable, as evidenced by an erosional surface. The Sundance Formation is divided into Sundance A and Sundance B, based on fossil data. Sundance A is predominantly green shale withmore » some limestone-shale interbeds. Sundance B lithology is similar to Sundance A with belemnoid guards. Toward the top of Sundance B are beds of glauconitic sandstones that grade upward into fossiliferous limestone. The contact between the Gypsum Spring, Sundance, and Morrison Formations appears to be gradational. The Western Interior sedimentary basin experienced four major transgressions during the Jurassic, resulting in the deposition of the Gypsum Spring and Sundance. Gypsum Spring deposition was influenced by paleohighs, specifically the Belt Island and Sheridan arch, and a warm, arid climate with rare storms. The lower Gypsum Spring unit was deposited in a restricted basin, with the middle and upper units reflecting subsequent deepening and freshening of the Jurassic sea. Most of the Sundance Formation was deposited in a relatively quiet, open-marine environment. Individual units represent shoaling conditions during minor regressions. Storms cut channels into sand bars, which were filled with coquinoid deposits.« less

Reactive-transport modelling of gypsum dissolution in a coastal karst aquifer in Puglia, southern Italy

NASA Astrophysics Data System (ADS)

Campana, Claudia; Fidelibus, Maria Dolores

2015-11-01

The gypsum coastal aquifer of Lesina Marina (Puglia, southern Italy) has been affected by sinkhole formation in recent decades. Previous studies based on geomorphologic and hydrogeological data ascribed the onset of collapse phenomena to the erosion of material that fills palaeo-cavities (suffosion sinkholes). The change in the hydrodynamic conditions of groundwater induced by the excavation of a canal within the evaporite formation nearly 100 years ago was identified as the major factor in triggering the erosion, while the contribution of gypsum dissolution was considered negligible. A combined reactive-transport/density-dependent flow model was applied to the gypsum aquifer to evaluate whether gypsum dissolution rate is a dominant or insignificant factor in recent sinkhole formation under current hydrodynamic conditions. The conceptual model was first defined with a set of assumptions based on field and laboratory data along a two-dimensional transect of the aquifer, and then a density-dependent, tide-influenced flow model was set up and solved using the numerical code SEAWAT. Finally, the resulting transient flow field was used by the reactive multicomponent transport model PHT3D to estimate the gypsum dissolution rate. The validation tests show that the model accurately represents the real system, and the multi-disciplinary approach provides consistent information about the causes and evolution time of dissolution processes. The modelled porosity development rate is too low to represent a significant contribution to the recent sinkhole formation in the Lesina Marina area, although it justifies cavity formation and cavity position over geological time.

Study of mixed mode fracture toughness and fracture trajectories in gypsum interlayers in corrosive environment

PubMed Central

Xiankai, Bao; Jinchang, Zhao

2018-01-01

Based on the engineering background of water dissolving mining for hydrocarbon storage in multi-laminated salt stratum, the mixed mode fracture toughness and fracture trajectory of gypsum interlayers soaked in half-saturated brine at various temperatures (20°C, 50°C and 80°C) were studied by using CSNBD (centrally straight-notched Brazilian disc) specimens with required inclination angles (0°, 7°, 15°, 22°, 30°, 45°, 60°, 75°, 90°) and SEM (scanning electron microscopy). The results showed: (i) The fracture load of gypsum specimens first decreased then increased with increasing inclination angle, due to the effect of friction coefficient. When soaked in brine, the fracture toughness of gypsum specimens gradually decreased with increasing brine temperature. (ii) When soaked in brine, the crystal boundaries of gypsum separated and became clearer, and the boundaries became more open between the crystals with increasing brine temperature. Besides, tensile micro-cracks appeared on the gypsum crystals when soaked in 50°C brine, and the intensity of tensile cracks became more severe when soaking in 80°C brine. (iii) The experimental fracture envelopes derived from the conventional fracture criteria and lay outside these conventional criteria. The experimental fracture envelopes were dependent on the brine temperature and gradually expanded outward as brine temperature increases. (iv) The size of FPZ (fracture process zone) was greatly dependent on the damage degree of materials and gradually increased with increase of brine temperature. The study has important implication for the control of shape and size of salt cavern. PMID:29410841

Decreasing Phosphorus Loss in Tile-Drained Landscapes Using Flue Gas Desulfurization Gypsum.

PubMed

King, K W; Williams, M R; Dick, W A; LaBarge, G A

2016-09-01

Elevated phosphorus (P) loading from agricultural nonpoint-source pollution continues to impair inland waterbodies throughout the world. The application of flue gas desulfurization (FGD) gypsum to agricultural fields has been suggested to decrease P loading because of its high calcium content and P sorbing potential. A before-after control-impact paired field experiment was used to examine the water quality effects of successive FGD gypsum applications (2.24 Mg ha; 1 ton acre each) to an Ohio field with high soil test P levels (>480 ppm Mehlich-3 P). Analysis of covariance was used to compare event discharge, dissolved reactive P (DRP), and total P (TP) concentrations and loadings in surface runoff and tile discharge between the baseline period (86 precipitation events) and Treatment Period 1 (42 precipitation events) and Treatment Period 2 (84 precipitation events). Results showed that, after the first application of FGD gypsum, event mean DRP and TP concentrations in treatment field tile water were significantly reduced by 21 and 10%, respectively, and DRP concentrations in surface runoff were significantly reduced by 14%; however, no significant reductions were noted in DRP or TP loading. After the second application, DRP and TP loads were significantly reduced in surface runoff (DRP, 41%; TP 40%), tile discharge (DRP, 35%; TP, 15%), and combined (surface + tile) discharge (DRP, 36%; TP, 38%). These findings indicate that surface application of FGD gypsum can be used as a tool to address elevated P concentrations and loadings in drainage waters. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Biological Responses of Raw 264.7 Macrophage Exposed to Two Strains of Stachybotrys chartarum Spores Grown on Four Different Wallboard Types

EPA Science Inventory

The focus of this research was to provide a better understanding of the health impacts caused by Stachybotrys chartarum (Houston and 51-11) spores grown on four gypsum products two of which were resistant to microbes. Raw 264.7 cells were exposed to whole spores and fragmented 51...

Gypsum addition to soils contaminated by red mud: implications for aluminium, arsenic, molybdenum and vanadium solubility.

PubMed

Lehoux, Alizée P; Lockwood, Cindy L; Mayes, William M; Stewart, Douglas I; Mortimer, Robert J G; Gruiz, Katalin; Burke, Ian T

2013-10-01

Red mud is highly alkaline (pH 13), saline and can contain elevated concentrations of several potentially toxic elements (e.g. Al, As, Mo and V). Release of up to 1 million m(3) of bauxite residue (red mud) suspension from the Ajka repository, western Hungary, caused large-scale contamination of downstream rivers and floodplains. There is now concern about the potential leaching of toxic metal(loid)s from the red mud as some have enhanced solubility at high pH. This study investigated the impact of red mud addition to three different Hungarian soils with respect to trace element solubility and soil geochemistry. The effectiveness of gypsum amendment for the rehabilitation of red mud-contaminated soils was also examined. Red mud addition to soils caused a pH increase, proportional to red mud addition, of up to 4 pH units (e.g. pH 7 → 11). Increasing red mud addition also led to significant increases in salinity, dissolved organic carbon and aqueous trace element concentrations. However, the response was highly soil specific and one of the soils tested buffered pH to around pH 8.5 even with the highest red mud loading tested (33 % w/w); experiments using this soil also had much lower aqueous Al, As and V concentrations. Gypsum addition to soil/red mud mixtures, even at relatively low concentrations (1 % w/w), was sufficient to buffer experimental pH to 7.5-8.5. This effect was attributed to the reaction of Ca(2+) supplied by the gypsum with OH(-) and carbonate from the red mud to precipitate calcite. The lowered pH enhanced trace element sorption and largely inhibited the release of Al, As and V. Mo concentrations, however, were largely unaffected by gypsum induced pH buffering due to the greater solubility of Mo (as molybdate) at circumneutral pH. Gypsum addition also leads to significantly higher porewater salinities, and column experiments demonstrated that this increase in total dissolved solids persisted even after 25 pore volume replacements. Gypsum

Microstructural and Microanalytical Study on Concrete Exposed to the Sulfate Environment

NASA Astrophysics Data System (ADS)

Qing, Fang; Beixing, Li; Jiangang, Yin; Xiaolu, Yuan

2017-11-01

Microstructural properties have been examined to investigate the effect of mineral admixtures on the sulfate resistance of concrete. Concrete and cement paste specimens made with ordinary Portland cement (OPC) or ordinary Portland cement incorporating 20% fly ash (FA) or 30% ground blast furnace slag (GBFS), were made and exposed to 250 cycles of the cyclic sulfate environment. Microstructural and Microanalytical study was conducted by means of x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and mercury intrusion porosimetry (MIP). Results indicate that the pore structure of concrete after sulfate exposure possesses the fractal feature. The OPC concrete presents more complex pore internal surface, higher porosity and less micro-pores than the concrete incorporating fly ash and GBFS. Portlandite in OPC concrete and OPC-FA concrete is mainly converted to gypsum; while for OPC-GBFS concrete, both gypsum and ettringite are formed. In the cyclic sulfate environment, repeated hydration and dehydration of sulfates produce the expansive stress in pores, aggravating the demolishment of concrete structure.

Study of Fresh and Hardening Process Properties of Gypsum with Three Different PCM Inclusion Methods

PubMed Central

Serrano, Susana; Barreneche, Camila; Navarro, Antonia; Haurie, Laia; Fernandez, A. Inés; Cabeza, Luisa F.

2015-01-01

Gypsum has two important states (fresh and hardened states), and the addition of phase change materials (PCM) can vary the properties of the material. Many authors have extensively studied properties in the hardened state; however, the variation of fresh state properties due to the addition of Micronal® DS 5001 X PCM into gypsum has been the object of few investigations. Properties in fresh state define the workability, setting time, adherence and shrinkage, and, therefore the possibility of implementing the material in building walls. The aim of the study is to analyze, compare and evaluate the variability of fresh state properties after the inclusion of 10% PCM. PCM are added into a common gypsum matrix by three different methods: adding microencapsulated PCM, making a suspension of PCM/water, and incorporating PCM through a vacuum impregnation method. Results demonstrate that the inclusion of PCM change completely the water required by the gypsum to achieve good workability, especially the formulation containing Micronal® DS 5001 X: the water required is higher, the retraction is lower (50% less) due to the organic nature of the PCM with high elasticity and, the adherence is reduced (up to 45%) due to the difference between the porosity of the different surfaces as well as the surface tension difference. PMID:28793584

Oriented attachment by enantioselective facet recognition in millimeter-sized gypsum crystals.

PubMed

Viedma, Cristóbal; Cuccia, Louis A; McTaggart, Alicia; Kahr, Bart; Martin, Alexander T; McBride, J Michael; Cintas, Pedro

2016-09-22

Crystal growth by oriented attachment involves the spontaneous self-assembly of adjoining crystals with common crystallographic orientations. Herein, we report the oriented attachment of gypsum crystals on agitation to form stereoselective mesoscale aggregates.

Uptake and speciation of uranium in synthetic gypsum (CaSO4•2H2O): Applications to radioactive mine tailings.

PubMed

Lin, Jinru; Sun, Wei; Desmarais, Jacques; Chen, Ning; Feng, Renfei; Zhang, Patrick; Li, Dien; Lieu, Arthur; Tse, John S; Pan, Yuanming

2018-01-01

Phosphogypsum formed from the production of phosphoric acid represents by far the biggest accumulation of gypsum-rich wastes in the world and commonly contains elevated radionuclides, including uranium, as well as other heavy metals and metalloids. Therefore, billions-of-tons of phosphogypsum stockpiled worldwide not only possess serious environmental problems but also represent a potential uranium resource. Gypsum is also a major solid constituent in many other types of radioactive mine tailings, which stems from the common usage of sulfuric acid in extraction processes. Therefore, management and remediation of radioactive mine tailings as well as future beneficiation of uranium from phosphogysum all require detailed knowledge about the nature and behavior of uranium in gypsum. However, little is known about the uptake mechanism or speciation of uranium in gypsum. In this study, synthesis experiments suggest an apparent pH control on the uptake of uranium in gypsum at ambient conditions: increase in U from 16 μg/g at pH = 6.5 to 339 μg/g at pH = 9.5. Uranium L 3 -edge synchrotron X-ray absorption spectroscopic analyses of synthetic gypsum show that uranyl (UO 2 ) 2+ at the Ca site is the dominant species. The EXAFS fitting results also indicate that uranyl in synthetic gypsum occurs most likely as carbonate complexes and yields an average U-O distance ∼0.25 Å shorter than the average Ca-O distance, signifying a marked local structural distortion. Applications to phosphogypsum from the New Wales phosphoric acid plant (Florida, USA) and uranium mine tailings from the Key Lake mill (Saskatchewan, Canada) show that gypsum is an important carrier of uranium over a wide range of pH and controls the fate of this radionuclide in mine tailings. Also, development of new technologies for recovering U from phosphogypsum in the future must consider lattice-bound uranyl in gypsum. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect Of Coir Fibres On The Compaction And Unconfined Compressive Strength Of Bentonite-Lime-Gypsum Mixture

NASA Astrophysics Data System (ADS)

Tilak B., Vidya; Dutta, Rakesh Kumar; Mohanty, Bijayananda

2015-06-01

This paper presents the effect of coir fibres on the compaction and unconfined compressive strength of a bentonite-lime-gypsum mixture. The coir fiber content varied from 0.5 to 2 %. The results indicated that the dry unit weight and the optimum moisture content of a bentonite - lime mix increased with the addition of gypsum. The unconfined compressive strength of the bentonite increased with the increase in the lime content up to 8 %. Beyond 8 %, the unconfined compressive strength decreased. The dry unit weight of the reference mix decreased, and the optimum moisture content increased with the addition of coir fibre. The unconfined compressive strength of the bentonite + 8 % lime mix increased up to 4 % with the gypsum. Beyond 4 %, the unconfined compressive strength decreased. The unconfined compressive strength of the reference mix increased with the addition of coir fibre up to a fibre content of 1.5 %. The unconfined compressive strength of the reference mix-coir fibre composite was less in comparison to the reference mix. The unconfined compressive strength of the bentonite increased with the addition of lime and gypsum and with the increase in the curing period. The improvement in the post-peak region was better for the reference mix with reinforced coir fibres as compared to the unreinforced reference mix. The improved post-peak behaviour of the bentonite-lime-gypsum-coir fibre mixture could boost the construction of temporary roads on such problematic soils. Further, its use will also provide an environmental motivation for providing a means of consuming large quantities of coir fibres.

Flue gas desulfurization gypsum and fly ash

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

Not Available

1992-05-01

The Cumberland Fossil Plant (CUF) is located in Stewart County, Tennessee, and began commercial operation in 1972. This is the Tennessee Valley Authority`s newest fossil (coal-burning) steam electric generating plant. Under current operating conditions, the plant burns approximately seven million tons of coal annually. By-products from the combustion of coal are fly ash, approximately 428,000 tons annually, and bottom ash, approximately 115,000 tons annually. Based on historical load and projected ash production rates, a study was initially undertaken to identify feasible alternatives for marketing, utilization and disposal of ash by-products. The preferred alternative to ensure that facilities are planned formore » all by-products which will potentially be generated at CUF is to plan facilities to handle wet FGD gypsum and dry fly ash. A number of different sites were evaluated for their suitability for development as FGD gypsum and ash storage facilities. LAW Engineering was contracted to conduct onsite explorations of sites to develop information on the general mature of subsurface soil, rock and groundwater conditions in the site areas. Surveys were also conducted on each site to assess the presence of endangered and threatened species, wetlands and floodplains, archaeological and cultural resources, prime farmland and other site characteristics which must be considered from an environmental perspective.« less

FEASIBILITY OF PRODUCING AND MARKETING BYPRODUCT GYPSUM FROM SO2 EMISSION CONTROL AT FOSSIL-FUEL-FIRED POWER PLANTS

EPA Science Inventory

The report gives results of a study to identify fossil-fuel-fired power plants that might, in competition with existing crude gypsum sources and other power plants, lower the cost of compliance with SO2 regulations by producing and marketing abatement gypsum. In the Eastern U.S.,...

Gypsum crystal size distribution in four continuous flow stirred slurry boric acid reactors in series compared with the batch

NASA Astrophysics Data System (ADS)

Çakal, G. Ö.; Eroğlu, İ.; Özkar, S.

2006-04-01

Colemanite, one of the important boron minerals, is dissolved in aqueous sulfuric acid to produce boric acid. In this reaction, gypsum is obtained as a by-product. Gypsum crystals are in the shape of thin needles. These crystals should be grown to an easily filterable size in order to increase the production yield and purity of boric acid. In this paper, the particle size distributions and the volume-weighted mean diameters of the gypsum crystals obtained in batch and continuous flow systems were compared. Experiments in both batch and continuous reactors were performed at a temperature of 85 °C, a stirring rate of 400 rpm, and the inlet CaO to SO42- molar ratio of 1.0 using colemanite mineral in particle size smaller than 150 μm. The average diameter of the gypsum crystals obtained at 3.5 h from the batch reactor was found to be 37-41 μm. This value for the continuous system at steady state was observed to change between 44-163 μm. The particle size of the gypsum crystals was found to increase with the residence time of the solid in the continuous system.

Mechanical properties of simulated Mars materials: gypsum-rich sandstones and lapilli tuff

USGS Publications Warehouse

Morrow, Carolyn; Lockner, David; Okubo, Chris

2013-01-01

Observations by the Mars Exploration Rover (MER) Opportunity, and other recent studies on diagenesis in the extensive equatorial layered deposits on Mars, suggest that the likely lithologies of these deposits are gypsum-rich sandstones and tuffaceous sediments (for example, Murchie and others, 2009; Squyres and others, 2012; Zimbelman and Scheidt, 2012). Of particular interest is how the diagenesis history of these sediments (degree of cementation and composition) influences the strength and brittle behavior of the material. For instance, fractures are more common in lower porosity materials under strain, whereas deformation bands, characterized by distributed strain throughout a broader discontinuity in a material, are common in higher porosity sedimentary materials. Such discontinuities can either enhance or restrict fluid flow; hence, failure mode plays an important role in determining the mechanics of fluid migration through sediments (Antonellini and Aydin, 1994; 1995; Taylor and Pollard, 2000; Ogilvie and Glover, 2001). As part of a larger study to characterize processes of fault-controlled fluid flow in volcaniclastic and gypsum-rich sediments on Mars, we have completed a series of laboratory experiments to focus on how gypsum clast content and degree of authigenic cementation affects the strength behavior of simulated Mars rocks. Both axial deformation and hydrostatic pressure tests were done at room temperature under dry conditions.

Modeling grain size variations of aeolian gypsum deposits at White Sands, New Mexico, using AVIRIS imagery

USGS Publications Warehouse

Ghrefat, H.A.; Goodell, P.C.; Hubbard, B.E.; Langford, R.P.; Aldouri, R.E.

2007-01-01

Visible and Near-Infrared (VNIR) through Short Wavelength Infrared (SWIR) (0.4-2.5????m) AVIRIS data, along with laboratory spectral measurements and analyses of field samples, were used to characterize grain size variations in aeolian gypsum deposits across barchan-transverse, parabolic, and barchan dunes at White Sands, New Mexico, USA. All field samples contained a mineralogy of ?????100% gypsum. In order to document grain size variations at White Sands, surficial gypsum samples were collected along three Transects parallel to the prevailing downwind direction. Grain size analyses were carried out on the samples by sieving them into seven size fractions ranging from 45 to 621????m, which were subjected to spectral measurements. Absorption band depths of the size fractions were determined after applying an automated continuum-removal procedure to each spectrum. Then, the relationship between absorption band depth and gypsum size fraction was established using a linear regression. Three software processing steps were carried out to measure the grain size variations of gypsum in the Dune Area using AVIRIS data. AVIRIS mapping results, field work and laboratory analysis all show that the interdune areas have lower absorption band depth values and consist of finer grained gypsum deposits. In contrast, the dune crest areas have higher absorption band depth values and consist of coarser grained gypsum deposits. Based on laboratory estimates, a representative barchan-transverse dune (Transect 1) has a mean grain size of 1.16 ??{symbol} (449????m). The error bar results show that the error ranges from - 50 to + 50????m. Mean grain size for a representative parabolic dune (Transect 2) is 1.51 ??{symbol} (352????m), and 1.52 ??{symbol} (347????m) for a representative barchan dune (Transect 3). T-test results confirm that there are differences in the grain size distributions between barchan and parabolic dunes and between interdune and dune crest areas. The t-test results

Seeking Election: Evaluating a Campaign for Public School Board Trusteeship

ERIC Educational Resources Information Center

Mueller, Robin

2011-01-01

Canadian public school board trustees are generally chosen by way of public ballot in civic elections. A comparison of board governance literature to a local narrative account of public school board elections exposes several gaps between espoused democratic ideals and the realities of public engagement in trustee selection. I investigate the…

Dynamic controls on accretion and lithification of modern gypsum-dominated thrombolites, Los Roques, Venezuela

NASA Astrophysics Data System (ADS)

Petrash, Daniel A.; Gingras, Murray K.; Lalonde, Stefan V.; Orange, François; Pecoits, Ernesto; Konhauser, Kurt O.

2012-03-01

Meter-sized thrombolites coated by well developed zonally differentiated microbial mats have been found growing in the shallow waters (depth < 1 m) of a restricted hypersaline lagoon on the Archipelago Los Roques in Venezuela. By contrast, within the deeper parts of the studied lagoon, sedimentation is characterized by several decimeters of organic-rich material containing gypsum granules lacking carbonate cementation. The lithification of the thrombolites is thought to have proceeded as follows. First, extracellular polymeric substances (EPS) comprising the microbial mat concentrate Ca2 + and other metal cations by adsorption from the hypersaline waters. Second, some of these bound metals then serve as nucleation sites for primary calcium carbonate (CaCO3) precipitation. Third, while carbonate phases are forming in some zones of the mat, in others zones they are being re-dissolved due to the acidity generated through the metabolism of sulfide-oxidizing bacteria, Fourth, as the dissolved sulfide is oxidized into sulfate, the pore-water become saturated with respect to gypsum (CaSO4·2H2O). Fifth, as primary gypsum precipitates within the structures, endolithic sulfate-reducing bacteria metabolize the sulfate moiety in the mineral phase, while simultaneously oxidizing the EPS trapped during accretion. Sixth, as microbial EPS degradation proceeds, the anaerobic oxidation of specific protein fractions of the EPS matrix leads to increased alkalinity, the partial dissolution of gypsum, supersaturation with respect to calcium carbonate, and ultimately pseudomorphic aragonite replacement; this differs from secondary calcite cements in being enriched in 12C, and depleted in minor and trace metals initially associated with the EPS. The biogeochemical processes occurring in this thrombolite-constructing lagoon represent a novel field site for studying the chemical and isotopic processes characterizing early diagenetic gypsum and the role microbes play in its precipitation

Mold growth on gypsum wallboard--a summary of three techniques.

PubMed

Menetrez, M Y; Foarde, K K; Webber, T D; Dean, T R; Betancourt, D A

2009-01-01

Reducing occupant exposure to mold growing on damp gypsum wallboard and controlling mold contamination in the indoor environment was studied through 1) delineation of environmental conditions required to promote and avoid mold growth and 2) efficacy testing of antimicrobial products, specifically cleaners and paints, on gypsum wallboard (GWB) surfaces. The effects of moisture and relative humidity (RH) on mold growth and transport are important in avoiding and eliminating problems. These effects have been demonstrated on GWB and are discussed in this article for use as control guidance. The authors discuss the efficacy of antimicrobial cleaners and paints to remove, eliminate, or control mold growth on GWB. Research to control Stachybotrys chartarum growth using 13 separate antimicrobial cleaners and nine varieties of antimicrobial paint on contaminated GWB was performed in laboratory testing. GWB surfaces were subjected to high RH. GWB control measures are summarized and combined, and the antimicrobial product results are explained.

Analyzing the rules of fracture and damage, and the characteristics of the acoustic emission signal of a gypsum specimen under uniaxial loading

NASA Astrophysics Data System (ADS)

Chen, Dong; Wang, En-yuan; Li, Nan

2017-08-01

In order to study the mechanism of rock bursts in a mined-out area of a gypsum mine, in this paper acoustic emission testing of the uniaxial compression of gypsum and sandstone samples is carried out. The case of rupture of the specimen is observed, and the load axial deformation curve and acoustic emission parameters are obtained for the whole process of specimen rupture. The similarities and differences between the gypsum and sandstone samples are determined in terms of their mechanical properties, their damage evolution laws and frequency band energy distributions, and the instantaneous energy characteristics of their acoustic emission. The results show that the main fracture morphology of gypsum is ‘eight’-type, and the macroscopic fracture morphology of sandstone is mainly of partial ‘Y’-type and inverted Y-type. The intensity and uniformity of the gypsum and sandstone of the medium are different; because the gypsum is more uniform, it does not show as much variation as sandstone, instead suddenly increasing and decreasing. The maximum value of the damage variable D of gypsum reached 1, but the maximum value of D of the sandstone only reached 0.9. The frequency band of the maximum energy of gypsum and sandstone gradually decreased across the the four stages of rupture, while the maximum energy percentage increased gradually. From the stage where damage gradually increases to the stage of integral fracture of the specimen, the instantaneous energy showed a certain degree of increase. With an increase in the strength of the sample, the maximum energy percentage of the two materials corresponding to each phase gradually increases, and from the stage where damage gradually increases to the stage of integral fracture of the specimen, the value of instantaneous energy obviously increases. The results indicate that gypsum mines will also experience rock bursts, as coal mines do, but the intensity will be different. Therefore, using the three indicators, the

Fabrication of B-type carbonate apatite blocks by the phosphorization of free-molding gypsum-calcite composite.

PubMed

Zaman, Chowdury Tanira; Takeuchi, Akari; Matsuya, Shigeki; Zaman, Q H M Shawket; Ishikawa, Kunio

2008-09-01

B-type carbonate apatite (CO3Ap) block may be an ideal artificial bone substitute because it is closer in chemical composition to bone mineral. In the present study, the feasibility to fabricate CO3Ap blocks was investigated using compositional transformation, which was based on the dissolution-precipitation reaction of a gypsum-calcite composite with free-molding behavior. For the compositional change, or phosphorization, gypsum-calcite composites of varying CaCO3 contents were immersed in 1 mol/L (NH4)3PO4 aqueous solution at 100 degrees C for 24 hours. No macroscopic changes were found after the treatment, whereas microscopic change was observed at SEM level. X-ray diffraction, Fourier transform infrared spectroscopy and CHN analysis indicated that the composites were B-type CO3Ap containing approximately 6-7 wt% of CO3, a value similar to that of biological bone apatite. Diametral tensile strength of the CO3Ap block was approximately 1-3 MPa. Based on the results obtained, it was therefore concluded that gypsum-calcite was a good candidate for the fabrication of CO3Ap blocks, coupled with the advantage that the composite can be molded to any shape by virtue of the setting property of gypsum.

Sulfide weathering in the Werenskioldbreen, Spitsbergen - A polar terrestrial analogue for gypsum deposition in the North Polar Region of Mars

NASA Astrophysics Data System (ADS)

Szynkiewicz, A.; Modelska, M.; Buczynski, S.; Borrok, D.; Pratt, L.

2010-12-01

Hydrated sulfates such as gypsum are important constituents of the low-elevation areas around the North Polar residual ice cap on Mars, but the origin of hydrological process which led to the formation and accumulation of gypsum is poorly understood. To address this uncertainty, we investigated the origin of proglacial gypsum in the Werenskioldbreen, a polythermal glacier of Spitsbergen in the Svalbard archipelago east of Greenland. We measured S isotopes, major chemistry and surface water flow rates to calculate SO4 fluxes from sulfide weathering in this polar climate. Sulfides comprised 0.02 to 0.42 weight % of the fine-grained fraction of proglacial sediments and their δ34S varied over the range of +9 to +16 ‰. The δ34S of dissolved SO4 in glacier melt waters (+9 to +17 ‰) was consistent with SO4 generation being dominated by sulfide oxidation. In summer 2008, the calculated SO4 flux was ~6,200 kg/day in the main glacier stream of the Werenskioldbreen discharging to the Greenland Sea and it translated to 4.3 x 105 mol/yr-km2 based on the scale of the entire Werenskioldbreen catchment (~27.4 km2). Our measured polar SO4 flux was 6 times larger than reported estimates for pyrite-derived SO4 loading in a considerably larger (1.78 x 106 km2) watershed of Northern Canada. This implies that small glacier catchments can generate an important global-scale flux of sulfide-derived SO4. Both evaporation and freezing of glacial waters lead to precipitation, accumulation, and temporary storage of gypsum in the proglacial zone. Poor preservation of gypsum on the surface of proglacial sediments mainly results from its quick dissolution during warmer condition when the hydrological cycle is most active. The observed distribution of gypsum and hydrated sulfates around the north polar ice residual deposits of Planum Boreum on Mars matches the spatial and geochemical patterns of gypsum formation controlled by sulfide weathering in terrestrial polar environments like

Fabrication of carbonate apatite blocks from set gypsum based on dissolution-precipitation reaction in phosphate-carbonate mixed solution.

PubMed

Nomura, Shunsuke; Tsuru, Kanji; Maruta, Michito; Matsuya, Shigeki; Takahashi, Ichiro; Ishikawa, Kunio

2014-01-01

Carbonate apatite (CO3Ap), fabricated by dissolution-precipitation reaction based on an appropriate precursor, is expected to be replaced by bone according to bone remodeling cycle. One of the precursor candidates is gypsum because it shows self-setting ability, which then enables it to be shaped and molded. The aim of this study, therefore, was to fabricate CO3Ap blocks from set gypsum. Set gypsum was immersed in a mixed solution of 0.4 mol/L disodium hydrogen phosphate (Na2HPO4) and 0.4 mol/L sodium hydrogen carbonate (NaHCO3) at 80-200°C for 6-48 h. Powder X-ray diffraction patterns and Fourier transform infrared spectra showed that CO3Ap block was fabricated by dissolution-precipitation reaction in Na2HPO4-NaHCO3 solution using set gypsum in 48 h when the temperature was 100°C or higher. Conversion rate to CO3Ap increased with treatment temperature. CO3Ap block containing a larger amount of carbonate was obtained when treated at lower temperature.

FGD gypsum filters remove soluble phosphorus from agricultural drainage waters

USDA-ARS?s Scientific Manuscript database

Decades of chicken litter applications has led to phosphorus (P) levels up to ten times the agronomic optimum in soils of the Delmarva Peninsula. This legacy P is a major source of P entering drainage ditches that eventually empty into the Chesapeake Bay. A Flue Gas Desulfurization (FGD) gypsum ditc...

Utilization of the gypsum from a wet limestone flue gas desulfurization process

USGS Publications Warehouse

Chou, I.-Ming; Patel, V.; Lytle, J.M.; Chou, S.J.; Carty, R.H.

1999-01-01

The authors have been developing a process which converts FGD-gypsum to ammonium sulfate fertilizer with precipitated calcium carbonate as a by-product during the conversion. Preliminary cost estimates suggest that the process is economically feasible when ammonium sulfate crystals are produced in a granular size (1.2 to 3.3 mm), instead of a powder form. However, if additional revenue from the sale of the PCC for higher-value commercial application is applicable, this could further improve the economics of the process. Ammonium sulfate is known to be an excellent source of nitrogen and sulfur in fertilizer for corn and wheat production. It was not known what impurities might co-exist in ammonium sulfate derived from scrubber gypsum. Before the product could be recommended for use on farm land, the impurities and their impact on soil productivity had to be assessed. The objectives of this phase of the study were to evaluate the chemical properties of ammonium sulfate made from the FGD-gypsum, to estimate its effects on soil productivity, and to survey the marketability of the two products. The results of this phase of the study indicated that the impurities in the ammonium sulfate produced would not impose any practical limitations on its use at application levels used by farmers. The market survey showed that the sale price of solid ammonium sulfate fertilizer increased significantly from 1974 at $110/ton to 1998 at $187/ton. Utilities currently pay $16 to $20/ton for the calcium carbonate they use in their flue gas scrubber system. The industries making animal-feed grade calcium supplement pay $30/ton to $67/m-ton for their source of calcium carbonate. Paper, paint, and plastic industries pay as much as $200 to $300/ton for their calcium carbonate filers. The increased sale price of solid ammonium sulfate fertilizer and the possible additional revenue from the sale of the PCC by-product could further improve the economics of producing ammonium sulfate from FGD-gypsum.

Use of flue gas desulfurization gypsum for leaching Cd and Pb in reclaimed tidal flat soil.

PubMed

Yang, Ping; Li, Xian; Tong, Ze-Jun; Li, Qu-Sheng; He, Bao-Yan; Wang, Li-Li; Guo, Shi-Hong; Xu, Zhi-Min

2016-04-01

A soil column leaching experiment was conducted to eliminate heavy metals from reclaimed tidal flat soil. Flue gas desulfurization (FGD) gypsum was used for leaching. The highest removal rates of Cd and Pb in the upper soil layers (0-30 cm) were 52.7 and 30.5 %, respectively. Most of the exchangeable and carbonate-bound Cd and Pb were removed. The optimum FGD gypsum application rate was 7.05 kg·m(-2), and the optimum leaching water amount for the application was 217.74 L·m(-2). The application of FGD gypsum (two times) and the extension of the leaching interval time to 20 days increased the heavy metal removal rate in the upper soil layers. The heavy metals desorbed from the upper soil layers were re-adsorbed and fixed in the 30-70 cm soil layers.

Prediction Model for Impulsive Noise on Structures

DTIC Science & Technology

2012-09-01

construction usually have an interior wall finish of: a) gypsum wallboard (also called plasterboard or drywall), b) plaster or c) wood paneling... Gypsum Plaster , Wall Board 11,67 0.04 NA For simply-supported beams vibrating in their fundamental mode, the value of KS is needed for...Dev of log10(f0) for wood panel interior to be average for wood walls with plaster or gypsum board interior. (8) L(w) based on estimated standard

Bacterial Communities and the Nitrogen Cycle in the Gypsum Soils of Cuatro Ciénegas Basin, Coahuila: A Mars Analogue

PubMed Central

López-Lozano, Nguyen E.; Eguiarte, Luis E.; Bonilla-Rosso, Germán; García-Oliva, Felipe; Martínez-Piedragil, Celeste; Rooks, Christine

2012-01-01

Abstract The OMEGA/Mars Express hyperspectral imager identified gypsum at several sites on Mars in 2005. These minerals constitute a direct record of past aqueous activity and are important with regard to the search of extraterrestrial life. Gale Crater was chosen as Mars Science Laboratory Curiosity's landing site because it is rich in gypsum, as are some desert soils of the Cuatro Ciénegas Basin (CCB) (Chihuahuan Desert, Mexico). The gypsum of the CCB, which is overlain by minimal carbonate deposits, was the product of magmatic activity that occurred under the Tethys Sea. To examine this Mars analogue, we retrieved gypsum-rich soil samples from two contrasting sites with different humidity in the CCB. To characterize the site, we obtained nutrient data and analyzed the genes related to the N cycle (nifH, nirS, and nirK) and the bacterial community composition by using 16S rRNA clone libraries. As expected, the soil content for almost all measured forms of carbon, nitrogen, and phosphorus were higher at the more humid site than at the drier site. What was unexpected is the presence of a rich and divergent community at both sites, with higher taxonomic diversity at the humid site and almost no taxonomic overlap. Our results suggest that the gypsum-rich soils of the CCB host a unique microbial ecosystem that includes novel microbial assemblies. Key Words: Cuatro Ciénegas Basin—Gale Crater—Gypsum soil microbial diversity—Molecular ecology—Nitrogen cycle. Astrobiology 12, 699–709. PMID:22920518

Gypsum adherence to forage: consideration for excessive ingestion by ruminates

USDA-ARS?s Scientific Manuscript database

Gypsum (calcium sulfate dihydrate, CaSO4•2H2O) has long been used as a soil amendment to improve soil conditions and its use has recently been encouraged by the USDA-NRCS for soil conservation through a new National Conservation Practice Standard: Code 333. However, there is concern regarding the e...

Fabrication of hydroxyapatite block from gypsum block based on (NH4)2HPO4 treatment.

PubMed

Suzuki, Yumiko; Matsuya, Shigeki; Udoh, Koh-ichi; Nakagawa, Masaharu; Tsukiyama, Yoshihiro; Koyano, Kiyoshi; Ishikawa, Kunio

2005-12-01

The aim of this study was to evaluate the feasibility of fabricating low-crystalline, porous apatite block using set gypsum as a precursor based on the fact that apatite is thermodynamically more stable than gypsum. When the set gypsum was immersed in 1 mol/L diammonium hydrogen phosphate aqueous solution at 100 degrees C, it transformed to low-crystalline porous apatite retaining its original shape. The transformation reaction caused a release of sulfate ions due to an ion exchange with phosphate ions, thus leading to a decrease in the pH of the solution. Then, due to decreased pH, dicalcium phosphate anhydrous--which has similar thermodynamic stability at lower pH--was also produced as a by-product. Apatite formed in the present method was low-crystalline, porous B-type carbonate apatite that contained approximately 0.5 wt% CO3, even though no carbonate sources--except carbon dioxide from air--were added to the reaction system. We concluded therefore that this is a useful bone filler fabrication method since B-type carbonate apatite is the biological apatite contained in bone.

Reforestation and landscape reconstruction in gypsum mine area from the semiarid region of NE Brazil

NASA Astrophysics Data System (ADS)

Bittar, S. M. B.; Straaten, P. V.; de Araujo Vieura Santos, M. de Fatima; Agra Bezerra da Silva, Y. J.; da Silva, M.; Saraiva de Melo Pinheiro, T.; Gusmao Didier de Moraes, F.; de Aguiar Accioly, A. M.; Alves de Santana, S. R.; dos Santos, H. A.; de Carvalho, D. M.; de Lima Ferreira, G.; de Carvalho Santos, C.

2012-04-01

In the Araripe region, Northeast Brazil, exist the world's second largest reserve of gypsum, estimated at over than one billion tons, which accounts for 95% of the Brazilian production and constitutes an important segment of the regional economy. The gypsum deposit occurs in the Lower Cretaceous Santana Formation of the Araripe basin, which is constituted by siltstones, marls, limestones, shales and gypsum layers. The ore extraction is from an open pit, on simple benches with a height of about 15 meters. Activities in mining operations involve stripping, drilling, loading explosives, blast, fragmentation and block loading / transport. Currently, gypsum mining and processing results in major changes in the landscape (pits and wastes heaps sedimentary rocks and soil mixture), deforestation of the "caatinga" ecosystem for use as firewood in small calcinations, dust pollution and changes in hydrology. To promote environmental remediation of this area, a multidisciplinary research has being done with the aim to support reforestation at the wastes heaps. The study involved the following activities: collection and physical, chemical and mineralogical characterization of mine waste materials; a floristic survey around the mines (botanical identification and measuring physical parameters in 16 plots, in order to identify which species are best suited to the conditions of the substrate at the mine site); an experiment (randomized block design) developed in a greenhouse, where seedlings of various native tree species were grown in a "constructed soil" made up of gypsum waste combined with chicken, goat and cattle manure, aimed to select tree species and soil treatment to be used in a waste heap; and an assessment of water quality for irrigation of the reforestation areas. The waste materials consist of large clayey aggregates, which may present physical/chemical properties unfavorable for plant development. The mineralogy of the sand fraction (> 85% quartz, gypsum and

Coal Combustion Residual Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard

EPA Pesticide Factsheets

This page contains documents related to the evaluation of coal combustion residual beneficial use of fly ash concrete and FGD gypsum wallboard including the evaluation itself and the accompanying appendices

Behavior of Steel-Sheathed Shear Walls Subjected to Seismic and Fire Loads.

PubMed

Hoehler, Matthew S; Smith, Christopher M; Hutchinson, Tara C; Wang, Xiang; Meacham, Brian J; Kamath, Praveen

2017-07-01

A series of tests was conducted on six 2.7 m × 3.7 m shear wall specimens consisting of cold-formed steel framing sheathed on one side with sheet steel adhered to gypsum board and on the opposite side with plain gypsum board. The specimens were subjected to various sequences of simulated seismic shear deformation and fire exposure to study the influence of multi-hazard interactions on the lateral load resistance of the walls. The test program was designed to complement a parallel effort at the University of California, San Diego to investigate a six-story building subjected to earthquakes and fires. The test results reported here indicate that the fire exposure caused a shift in the failure mode of the walls from local buckling of the sheet steel in cases without fire exposure, to global buckling of the sheet steel with an accompanying 35 % reduction in lateral load capacity after the wall had been exposed to fire. This behavior appears to be predictable, which is encouraging from the standpoint of residual lateral load capacity under these severe multi-hazard actions.

The potential leaching and mobilization of trace elements from FGD-gypsum of a coal-fired power plant under water re-circulation conditions.

PubMed

Córdoba, Patricia; Castro, Iria; Maroto-Valer, Mercedes; Querol, Xavier

2015-06-01

Experimental and geochemical modelling studies were carried out to identify mineral and solid phases containing major, minor, and trace elements and the mechanism of the retention of these elements in Flue Gas Desulphurisation (FGD)-gypsum samples from a coal-fired power plant under filtered water recirculation to the scrubber and forced oxidation conditions. The role of the pH and related environmental factors on the mobility of Li, Ni, Zn, As, Se, Mo, and U from FGD-gypsums for a comprehensive assessment of element leaching behaviour were also carried out. Results show that the extraction rate of the studied elements generally increases with decreasing the pH value of the FGD-gypsum leachates. The increase of the mobility of elements such as U, Se, and As in the FGD-gypsum entails the modification of their aqueous speciation in the leachates; UO2SO4, H2Se, and HAsO2 are the aqueous complexes with the highest activities under acidic conditions. The speciation of Zn, Li, and Ni is not affected in spite of pH changes; these elements occur as free cations and associated to SO4(2) in the FGD-gypsum leachates. The mobility of Cu and Mo decreases by decreasing the pH of the FGD-gypsum leachates, which might be associated to the precipitation of CuSe2 and MoSe2, respectively. Time-of-Flight mass spectrometry of the solid phase combined with geochemical modelling of the aqueous phase has proved useful in understanding the mobility and geochemical behaviour of elements and their partitioning into FGD-gypsum samples. Copyright © 2015. Published by Elsevier B.V.

Theoretical and Numerical Investigation of the Cavity Evolution in Gypsum Rock

NASA Astrophysics Data System (ADS)

Li, Wei; Einstein, Herbert H.

2017-11-01

When water flows through a preexisting cylindrical tube in gypsum rock, the nonuniform dissolution alters the tube into an enlarged tapered tube. A 2-D analytical model is developed to study the transport-controlled dissolution in an enlarged tapered tube, with explicit consideration of the tapered geometry and induced radial flow. The analytical model shows that the Graetz solution can be extended to model dissolution in the tapered tube. An alternative form of the governing equations is proposed to take advantage of the invariant quantities in the Graetz solution to facilitate modeling cavity evolution in gypsum rock. A 2-D finite volume model was developed to validate the extended Graetz solution. The time evolution of the transport-controlled and the reaction-controlled dissolution models for a single tube with time-invariant flow rate are compared. This comparison shows that for time-invariant flow rate, the reaction-controlled dissolution model produces a positive feedback between the tube enlargement and dissolution, while the transport-controlled dissolution does not.

Hydrologic transport of fecal bacteria attenuated by flue gas desulfurization gypsum

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization (FGD) gypsum is a byproduct of coal-fired power plants. As a soil amendment for crop and pasture production it may increase water infiltration, reduce soil erosion, and decrease nutrient losses from applications of animal manures. Broiler litter is used as a source of plan...

High-yield synthesis of vaterite microparticles in gypsum suspension system via ultrasonic probe vibration/magnetic stirring

NASA Astrophysics Data System (ADS)

Wang, Bo; Pan, Zihe; Cheng, Huaigang; Chen, Zuliang; Cheng, Fangqin

2018-06-01

Vaterite-type calcium carbonate particles have some unique properties such as high hydrophilicity, large surface areas, and hierarchical structures consisting of primary vaterite particles in comparison with calcite or aragonite-type polymorphs. In this paper, gypsum (CaSO4·2H2O) suspension is used to synthesize micro-sized vaterite CaCO3 through magnetic stirring (MS) and ultrasonic probe vibration (UPV) methods. The effects of ammonia concentration, CO2 flow rate, solid-liquid ratio on the gypsum carbonation process, mineral phase composition, morphology and particle size distribution of CaCO3 are investigated. The results show that the carbonation process is significantly influenced by ammonia concentration, CO2 flow rate and ultrasound. Comparing with magnetic stirring, ultrasonic probe vibration take less time to reach the complete carbonate reaction. Gypsum is transformed to vaterite with the conversion rate about ∼95% when the mole ratio of NH4+/Ca2+ is 2.4 otherwise the carbonation reaction was uncompleted with gypsum residues left. Comparing with MS method, the UPV method resulted in smaller size and narrower size distribution of as-prepared microparticles and approximately 80% reduction of the particle size was achieved. It is established that increasing the solid-liquid ratio resulted in larger particle size in MS system and smaller particle size in UPV system. Increasing CO2 flow rate caused the particle size decreased in MS system and increased in UPV system.

Bacterial communities and the nitrogen cycle in the gypsum soils of Cuatro Ciénegas Basin, coahuila: a Mars analogue.

PubMed

López-Lozano, Nguyen E; Eguiarte, Luis E; Bonilla-Rosso, Germán; García-Oliva, Felipe; Martínez-Piedragil, Celeste; Rooks, Christine; Souza, Valeria

2012-07-01

The OMEGA/Mars Express hyperspectral imager identified gypsum at several sites on Mars in 2005. These minerals constitute a direct record of past aqueous activity and are important with regard to the search of extraterrestrial life. Gale Crater was chosen as Mars Science Laboratory Curiosity's landing site because it is rich in gypsum, as are some desert soils of the Cuatro Ciénegas Basin (CCB) (Chihuahuan Desert, Mexico). The gypsum of the CCB, which is overlain by minimal carbonate deposits, was the product of magmatic activity that occurred under the Tethys Sea. To examine this Mars analogue, we retrieved gypsum-rich soil samples from two contrasting sites with different humidity in the CCB. To characterize the site, we obtained nutrient data and analyzed the genes related to the N cycle (nifH, nirS, and nirK) and the bacterial community composition by using 16S rRNA clone libraries. As expected, the soil content for almost all measured forms of carbon, nitrogen, and phosphorus were higher at the more humid site than at the drier site. What was unexpected is the presence of a rich and divergent community at both sites, with higher taxonomic diversity at the humid site and almost no taxonomic overlap. Our results suggest that the gypsum-rich soils of the CCB host a unique microbial ecosystem that includes novel microbial assemblies.

Populations of some molds in water-damaged homes may differ if the home was constructed with gypsum drywall compared to plaster

EPA Science Inventory

Starting in the 1940s, gypsum drywall began replacing plaster and lathe in the U.S. home construction industry. Our goal was to evaluate whether some mold populations differ in water- damaged homes primarily constructed with gypsum drywall compared to plaster. The dust samples fr...

The status of Lepidospartum burgessii (Burgess Broomshrub or Gypsum Broomscale)

Treesearch

Juanita A. R. Lndyman; Patricia Gegick

2001-01-01

Lepidospartum burgessii is designated a Species of Concern by the U.S. Fish and Wildlife Service. This shrub is endemic to gypsum soils in north Culberson County, Texas and southern Otero County, New Mexico. In 1991-92 the condition and number of plants in New Mexico were examined but otherwise little was known about the ecology or biology of this species. Our...

Towards establishing a combined rate law of nucleation and crystal growth - The case study of gypsum precipitation

NASA Astrophysics Data System (ADS)

Rendel, Pedro M.; Gavrieli, Ittai; Wolff-Boenisch, Domenik; Ganor, Jiwchar

2018-03-01

The main obstacle in the formulation of a quantitative rate-model for mineral precipitation is the absence of a rigorous method for coupling nucleation and growth processes. In order to link both processes, we conducted a series of batch experiments in which gypsum nucleation was followed by crystal growth. Experiments were carried out using various stirring methods in several batch vessels made of different materials. In the experiments, the initial degree of supersaturation of the solution with respect to gypsum (Ωgyp) was set between 1.58 and 1.82. Under these conditions, heterogeneous nucleation is the dominant nucleation mode. Based on changes in SO42- concentration with time, the induction time of gypsum nucleation and the following rate of crystal growth were calculated for each experiment. The induction time (6-104 h) was found to be a function of the vessel material, while the rates of crystal growth, which varied over three orders of magnitude, were strongly affected by the stirring speed and its mode (i.e. rocking, shaking, magnetic stirrer, and magnetic impeller). The SO42- concentration data were then used to formulate a forward model that couples the simple rate laws for nucleation and crystal growth of gypsum into a single kinetic model. Accordingly, the obtained rate law is based on classical nucleation theory and heterogeneous crystal growth.

Residual effects of monoammonium phosphate, gypsum and elemental sulfur on cadmium phytoavailability and translocation from soil to wheat in an effluent irrigated field.

PubMed

Qayyum, Muhammad Farooq; Rehman, Muhammad Zia Ur; Ali, Shafaqat; Rizwan, Muhammad; Naeem, Asif; Maqsood, Muhammad Aamer; Khalid, Hinnan; Rinklebe, Jörg; Ok, Yong Sik

2017-05-01

Cadmium (Cd) accumulation in agricultural soils is one of the major threats to food security. The application of inorganic amendments such as mono-ammonium phosphate (MAP), gypsum and elemental sulfur (S) could alleviate the negative effects of Cd in crops. However, their long-term residual effects on decreasing Cd uptake in latter crops remain unclear. A field that had previously been applied with treatments including control and 0.2, 0.4 and 0.8% by weight of each MAP, gypsum and S, and grown with wheat and rice and thereafter wheat in the rotation was selected for this study. Wheat (Triticum aestivum L.) was grown in the same field as the third crop without further application of amendments to evaluate the residual effects of the amendments on Cd uptake by wheat. Plants were harvested at maturity and grain, and straw yield along with Cd concentration in soil, straw, and grains was determined. The addition of MAP and gypsum significantly increased wheat growth and yield and decreased Cd accumulation in straw and grains compared to control while the reverse was found in S application. Both MAP and gypsum decreased AB-DTPA extractable Cd in soil while S increased the bioavailable Cd in soil. Both MAP and gypsum increased the Cd immobilization in the soil and S decreased Cd immobilization in a dose-additive manner. We conclude that MAP and gypsum had a significant residual effect on decreasing Cd uptake in wheat. The cost-benefit ratio revealed that gypsum is an effective amendment for decreasing Cd concentration in plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

A low-temperature ductile shear zone: The gypsum-dominated western extension of the brittle Fella-Sava Fault, Southern Alps.

PubMed

Bartel, Esther Maria; Neubauer, Franz; Heberer, Bianca; Genser, Johann

2014-12-01

Based on structural and fabric analyses at variable scales we investigate the evaporitic gypsum-dominated Comeglians-Paularo shear zone in the Southern Alps (Friuli). It represents the lateral western termination of the brittle Fella-Sava Fault. Missing dehydration products of gypsum and the lack of annealing indicate temperatures below 100 °C during development of the shear zone. Despite of such low temperatures the shear zone clearly exhibits mylonitic flow, thus evidencing laterally coeval activity of brittle and viscous deformation. The dominant structures within the gypsum rocks of the Lower Bellerophon Formation are a steeply to gently S-dipping foliation, a subhorizontal stretching lineation and pure shear-dominated porphyroclast systems. A subordinate simple shear component with dextral displacement is indicated by scattered σ-clasts. Both meso- and microscale structures are characteristic of a subsimple shear type of deformation with components of both coaxial and non-coaxial strain. Shortening in a transpressive regime was accommodated by right-lateral displacement and internal pure shear deformation within the Comeglians-Paularo shear zone. The shear zone shows evidence for a combination of two stretching faults, where stretching occurred in the rheologically weaker gypsum member and brittle behavior in enveloping lithologies.

Urea hydrolysis and calcium carbonate precipitation in gypsum-amended broiler litter.

USDA-ARS?s Scientific Manuscript database

Broiler litter (BL) contains significant amounts of organic nitrogen (N) in the form of urea which is subject to ammonia (NH3) volatilization. Previous work has shown that the addition of gypsum to BL can increase nitrogen (N) mineralization, and decrease NH3 losses due to a decrease in pH but the ...

Use of FGD gypsum to reduce p loss from agricultural fields

USDA-ARS?s Scientific Manuscript database

Controlling P loss from agricultural fields has become a major issue in recent years, especially in areas where manure is used as nutrient sources. It is believed that FGD gypsum can be used as a management practice to reduce soluble P loss. Thus, the objective of this study was to determine FGD gy...

23. VIEW TOWARD EAST CORNER OF ROOM 205. FORMER SKYLIGHT ...

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

23. VIEW TOWARD EAST CORNER OF ROOM 205. FORMER SKYLIGHT IN SLOPED GYPSUM BOARD CEILING HAS BEEN ROOFED OVER. WALLS ARE A COMBINATION OF GYPSUM BOARD AND WOOD PLANK. WOOD POST SUPPORTS BEAM AT NORTHEAST WALL. - Presidio of San Francisco, Cavalry Stables, Cowles Street, between Lincoln Boulevard & McDowell Street, San Francisco, San Francisco County, CA

Hydrologic transport of fecal bacteria attenuated by flu gas desulfurized (FGD) gypsum

USDA-ARS?s Scientific Manuscript database

Background Flue gas desulfurized (FGD) gypsum is a byproduct of coal-fired power plants. As a soil amendment for crop production it has the potential of improving soil water infiltration, soil conservation, and decreasing nutrient losses from broiler litter applications. Because broiler litter is a ...

Decreasing phosphorus loss in tile-drained landscapes using flue gas desulfurization gypsum

USDA-ARS?s Scientific Manuscript database

Elevated phosphorus (P) loading from agricultural non-point source pollution continues to impair inland waterbodies throughout the world. The application of flue gas desulfurization (FGD) gypsum to agricultural fields has been suggested to decrease P loading because of its high calcium content and P...

Origin and diagenetic evolution of gypsum and microbialitic carbonates in the Late Sag of the Namibe Basin (SW Angola)

NASA Astrophysics Data System (ADS)

Laurent, Gindre-Chanu; Edoardo, Perri; Ian, Sharp R.; Peacock, D. C. P.; Roger, Swart; Ragnar, Poulsen; Hercinda, Ferreira; Vladimir, Machado

2016-08-01

Ephemeral evaporitic conditions developed within the uppermost part of the transgressive Late Sag sequence in the Namibe Basin (SW Angola), leading to the formation of extensive centimetre- to metre-thick sulphate-bearing deposits and correlative microbialitic carbonates rich in pseudomorphs after evaporite crystals. The onshore pre-salt beds examined in this study are located up to 25 m underneath the major mid-Aptian evaporitic succession, which is typified at the outcrop by gypsiferous Bambata Formation and in the subsurface by the halite-dominated Loeme Formation. Carbonate-evaporite cycles mostly occur at the top of metre-thick regressive parasequences, which progressively onlap and overstep landward the former faulted (rift) topography, or fill major pre-salt palaeo-valleys. The sulphate beds are made up of alabastrine gypsum associated with embedded botryoidal nodules, dissolution-related gypsum breccia, and are cross-cut by thin satin-spar gypsum veins. Nodular and fine-grained fabrics are interpreted as being diagenetic gypsum deposits resulting from the dissolution and recrystallisation of former depositional subaqueous sulphates, whereas gypsum veins and breccia result from telogenetic processes. The carbonates display a broader diversity of facies, characterised by rapid lateral variations along strike. Thin dolomitic and calcitic bacterial-mediated filamentous microbialitic boundstones enclose a broad variety of evaporite pseudomorphs and can pass laterally over a few metres into sulphate beds. Dissolution-related depositional breccias are also common and indicate early dissolution of former evaporite layers embedded within the microbialites. Sulphate and carbonate units are interpreted as being concomitantly deposited along a tide-dominated coastal supra- to intertidal- sabkha and constitute high-frequency hypersaline precursor events, prior to the accumulation of the giant saline mid-Aptian Bambata and Loeme Formations. Petrographic and geochemical

Exterior Decay of Wood-Plastic Composite Boards: Characterization and Magnetic Resonance Imaging

Treesearch

Rebecca Ibach; Grace Sun; Marek Gnatowski; Jessie Glaeser; Mathew Leung; John Haight

2016-01-01

Magnetic resonance imaging (MRI) was used to evaluate free water content and distribution in wood-plastic composite (WPC) materials decayed during exterior exposure near Hilo, Hawaii. Two segments of the same board blend were selected from 6 commercial decking boards that had fungal fruiting bodies. One of the two board segments was exposed in sun, the other in shadow...

The Effect of Orthodontic Model Fabrication Procedures on Gypsum Materials.

DTIC Science & Technology

1992-06-01

views expressed in this paper are exclusively those of the author and do not reflect those of the United States Air Force Dental Corps, the United...Artificial Stone ............... 6 1.3 Improved Dental Stone . . . . . . . . . . . . . 7 1.4 Manipulation Techniques . . . . . . . . . . . . 10 1.5 Mixing...properties which can be obtained, 9 , 13- 42 gypsum has been found to have applications in most dental specialties, orthodontics being no exception. Since

Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples

NASA Astrophysics Data System (ADS)

Milsch, Harald; Priegnitz, Mike

2012-12-01

We report on changes in P and S-wave velocities and rock microstructure induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air, at ambient pressure, and temperatures between 378 and 423 K. Dehydration did not proceed homogeneously but via a reaction front moving sample inwards separating an outer highly porous rim from the remaining gypsum which, above approximately 393 (±5) K, concurrently decomposed into hemihydrate. Overall porosity was observed to continuously increase with reaction progress from approximately 2% for fully hydrated samples to 30% for completely dehydrated ones. Concurrently, P and S-wave velocities linearly decreased with porosity from 5.2 and 2.7 km/s to 1.0 and 0.7 km/s, respectively. It is concluded that a linearized empirical Raymer-type model extended by a critical porosity term and based on the respective time dependent mineral and pore volumes reasonably replicates the P and S-wave data in relation to reaction progress and porosity.

Composting and gypsum amendment of broiler litter to reduce nutrient leaching loss

USDA-ARS?s Scientific Manuscript database

Relative to fresh broiler litter, little is known about the dynamics of composted litter derived-nutrient in the ecosystem. In this study, the potential leaching losses of nutrients from compost relative to fresh broiler litter along with flue gas desulfurization (FGD gypsum), as a nutrient immobil...

Results using flue gas desulfurization gypsum in soilless substrates for greenhouse crops

USDA-ARS?s Scientific Manuscript database

Recent availability of Flue Gas Desulfurization gypsum (FGDG) has led to interested in its possible use in horticulture greenhouse production. Three studies were conducted to determine the effects of increasing rates of FGDG on six greenhouse crops. In the first study, substrates (6:1 pine bark:san...

The structural and functional organization of the vestibular apparatus of rats exposed to weightlessness for 20 days on board the Sputnik "Kosmos-782".

PubMed

Vinnikov, Y A; Gazenko, O G; Titova, L K; Bronstein, A A; Govardovskii, V I; Gribakin, F G; Pevzner, R A; Aronova, M Z; Kharkeevich, T A; Tsirulis, T P; Pyatkina, G A; Lichakov, D V; Pal'mbach, L P; Anichin, V F

1979-01-01

This investigation of the vestibular apparatus of rats exposed for 20 days to weightlessness on board an earth satellite and to acceleration during take-off and landing has revealed a set of changes in the structural and functional organization, such as adjoinment of the otolith to the utricle receptor surface and peripheral localization of the nucleoli inside the receptor cells' nuclei. Destruction of some receptor cells, apparently due to increased swelling of the vestibular apparatus tissue and alteration of the shape and structure of the otoconia were observed. In the horizontal crista, detachment of the cupula took place.

Simplified Calculation Model and Experimental Study of Latticed Concrete-Gypsum Composite Panels

PubMed Central

Jiang, Nan; Ma, Shaochun

2015-01-01

In order to address the performance complexity of the various constituent materials of (dense-column) latticed concrete-gypsum composite panels and the difficulty in the determination of the various elastic constants, this paper presented a detailed structural analysis of the (dense-column) latticed concrete-gypsum composite panel and proposed a feasible technical solution to simplified calculation. In conformity with mechanical rules, a typical panel element was selected and divided into two homogenous composite sub-elements and a secondary homogenous element, respectively for solution, thus establishing an equivalence of the composite panel to a simple homogenous panel and obtaining the effective formulas for calculating the various elastic constants. Finally, the calculation results and the experimental results were compared, which revealed that the calculation method was correct and reliable and could meet the calculation needs of practical engineering and provide a theoretical basis for simplified calculation for studies on composite panel elements and structures as well as a reference for calculations of other panels. PMID:28793631

Simplified Calculation Model and Experimental Study of Latticed Concrete-Gypsum Composite Panels.

PubMed

Jiang, Nan; Ma, Shaochun

2015-10-27

In order to address the performance complexity of the various constituent materials of (dense-column) latticed concrete-gypsum composite panels and the difficulty in the determination of the various elastic constants, this paper presented a detailed structural analysis of the (dense-column) latticed concrete-gypsum composite panel and proposed a feasible technical solution to simplified calculation. In conformity with mechanical rules, a typical panel element was selected and divided into two homogenous composite sub-elements and a secondary homogenous element, respectively for solution, thus establishing an equivalence of the composite panel to a simple homogenous panel and obtaining the effective formulas for calculating the various elastic constants. Finally, the calculation results and the experimental results were compared, which revealed that the calculation method was correct and reliable and could meet the calculation needs of practical engineering and provide a theoretical basis for simplified calculation for studies on composite panel elements and structures as well as a reference for calculations of other panels.

A study of the effectiveness of the use of gypsum and volcanic ash against the stability of clay soil in terms of UCT and CBR values

NASA Astrophysics Data System (ADS)

Roesyanto; Iskandar, R.; Hastuty, IP; Lubis, AIU

2018-02-01

Soil stabilization is an effort to improve engineering properties of soil. The conventional soil stabilization is by adding additives to the soil such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and volcanic ash. The research purposes were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% volcanic ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT values of original soil and original soil plus 2% gypsum were 1.40 kg/cm2 and 1.66 kg/cm2 respectively. The CBR soaked and unsoaked values of original soil were 4.44% and 6.28% correspondingly. Meanwhile, CBR soaked and CBR unsoaked values of original soil plus 2% gypsum were 6.74% and 8.02% respectively. The research results showed that the additives materials of gypsum and volcanic ash improved the engineering properties of clay. The UCT result from the stabilized soil by 2% gypsum and 10% volcanic ash gave value of 2.79 kg/cm2 (increased 99.28% from original soil). For CBR test, the most effective mixture were in variation of 2% gypsum and 9% volcanic ash which gave value of 9.07% (104.27% increase from original soil) for CBR soaked and 10.29% (63.85% increase from original soil) for CBR unsoaked. The stabilized soil with 2% gypsum and 9% volcanic ash was classified as CL based on USCS and was classified as A-6 (4) based on AASHTO classification system.

Evaluating the fate of mercury and other metals across the life-cycle stages from the use of FGD gypsum for wallboard production

EPA Science Inventory

In 2007, 12.3 million tons of flue gas desulfurization (FGD) gypsum was produced due to air emission controls at coal-fired power plants. With increasing use of wet scrubbers in response to more stringent air pollution control requirements, FGD gypsum production is expected to in...

Preparation and evaluation of lignosulfonates as a dispersant for gypsum paste from acid hydrolysis lignin.

PubMed

Matsushita, Yasuyuki; Yasuda, Seiichi

2005-03-01

In order to effectively utilize a by-product of the acid saccharification process of woody materials, the chemical conversion of guaiacyl sulfuric acid lignin (SAL), one of the acid hydrolysis lignins, into water-soluble sulfonated products with high dispersibitity was investigated. At first, SAL was phenolated (P-SAL) to enhance the solubility and reactivity. Lignosulfonates were prepared from P-SAL by three methods of hydroxymethylation followed by neutral sulfonation (two-step method), sulfomethylation (one-step method) and arylsulfonation. Surprisingly, all prepared lignosulfonates possessed 30 to 70% higher dispersibility for gypsum paste than the commercial lignosulfonate. Evaluation of the preparations for gypsum paste suggested that the higher molecular weights and sulfur contents of the preparations increased their dispersibility.

75 FR 3911 - Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-25

...: The Advisory Board was established under the Energy Employees Occupational Illness Compensation... employees at any Department of Energy facility who were exposed to radiation but for whom it is not feasible... Labor (DOL) Program Update; Department of Energy (DOE) Program Update; OCAS Science Update; Special...

The gypsophyte Gypsophila struthium as nurse plant for vegetation recovery in degraded gypsum substrates

NASA Astrophysics Data System (ADS)

María Foronda, Ana; Pueyo, Yolanda; Castillejo, José Miguel; Alados, Conceción L.

2017-04-01

Degraded areas such as quarries or dumps are devoid of vegetation where the spontaneous vegetation recovery is a very slow process that requires restoration actions, especially under harsh environmental conditions such as arid conditions and special substrates. Specifically, gypsum substrates have physical and chemical limitations such as surface crusts, poor water availability or high concentrations of SO4 and Ca. Some plants, the so called gypsophytes, are adapted to tolerate such limitations and thus, might be able to establish in gypsum bare soils. Thus, well adapted gypsophytes might play an important role in vegetation recovery by acting as ecosystem engineers, improving the environmental conditions under their canopy and facilitating the establishment of other species. Facilitation is being recently considered as a key process in restoration practices because it might enhance restoration effectiveness by favoring the plant establishment and therefore, plant succession. The aim of this study was to test the effectiveness of a gypsophyte (Gypsophila struthium) in facilitating the establishment and development of other species and thus in vegetation recovery of degraded gypsum substrates. To address this objective, a sowing and planting experiment was set in November 2014 in a gypsum dump located in Andorra municipality (Teruel, NE Spain). Forty well-established adults of G. struthium previously planted in that dump were employed as nurse plants in the experiment. Two species were used as test species in the experiment: Helianthemum squamatum (gypsophyte) and Stipa lagascae (non-gypsophyte). Seeds and seedlings of those test species were sowed and planted in two different microsites: under the canopy and in the surrounding bare soil of each G. struthium individual (n=80 per test species). Germination, survival and growth of test species were surveyed twice a year during two years. Soil compaction and soil temperature were seasonally measured at both microsites

Carbonate speleothems from western Mediterranean gypsum karst: palaeoclimate implications

NASA Astrophysics Data System (ADS)

Columbu, Andrea; Drysdale, Russell; Woodhead, Jon; Chiarini, Veronica; De Waele, Jo; Hellstrom, John; Forti, Paolo; Sanna, Laura

2016-04-01

Gypsum caves are uncommon environments for carbonate speleothems (cave deposits). Contrary to limestone caves, the only source of non-atmospheric carbon is from biogenic CO2 produced by the overlying soils. Enhanced CO2 content in soils is in turn related with climate, where warm temperatures and high humidity favour plant activity .().....(Fairchild and Baker, 2012). Although poorly decorated, the exploration of northern Italian and Spanish gypsum karst systems reveals the existence of several generations of carbonate speleothems, which have been dated with the U-Th series method .()......(Hellstrom, 2003; Scholz and Hoffmann, 2008). Their ages coincide with current and previous two interglacials (MIS 1, 5e and 7e and Greenland interstadials (GIS) 19, 20, 21 and 24. Considering that these periods are amongst the most pronounced warm-wet pulsations over the last 250,000 ...(Martrat et al., 2007; NGRIP, 2004), and that CO2 has a fundamental role in this karst process, this study explores the climate-driven hydrogeological conditions necessary to trigger carbonate deposition in gypsum voids. The further correlation with sapropel events 5, 4, 3 and 1, considered symptomatic of enhanced rainfall across the whole Mediterranean basin .(.)(Emeis et al., 1991), highlights the importance of flow-rate in the fracture network and infiltration of meteoric water into the caves. The combination of high CO2 and a phreatic status of the fracture network is thus indispensable for the formation of carbonate speleothems in gypsum karst. This condition appears to be triggered by periods of orbital precession minimum, when the monsoonal activity peaked in the Atlantic area. Stable oxygen isotope signatures suggest that the speleothems did not grow during any interglacial-glacial or main interstadial-stadial transitions, confirming that variations from optimum climate conditions may hamper the formation of this category of speleothems. New speleological exploration and sampling campaign

Evaluation of Potential Damage to Unconventional Structures by Sonic Booms

DTIC Science & Technology

1990-05-01

plaster and gypsum board caused by sonic boom is broken...on wood lath 3.3 5.6 2. Plaster on gyplath 7.5 16 3. Plaster on expanded metal lath 16 16 4. Plaster on concrete block 16 16 5. Gypsum board (new) 16... wallboard (also called plasterboard or drywall), it is assumed that interior walls of unconventional historic wood frame buildings used plaster instead.

Mixture of natural fiber with gypsum to improve the fire resistance rating of a fire door: The effect of kapok fiber

NASA Astrophysics Data System (ADS)

Azieyanti, N. A.; Hakim, Alif; Hasini, Hasril

2017-10-01

A composite mixture of gypsum and natural fibers has been considered in this study to enhance the fire resistance rating of a fire door. Previously the materials used to make a fire door are gypsum and fiber wool where it acts as a protective coating. Normally this fire door must be compact and able to close on its own. Natural fibers have the ability to replace glass fiber cotton because of its features that are available in fiber glass wool. When using fiberglass, it can cause health problem once it is swallowed and inhaled, and may remain in the lungs indefinitely. It also can contribute to lungs cancer. Kapok fiber has been used in this experiment as natural fibers. The objective of the experiment is to analyze the fire resistant rating of the composite mixture of gypsum with kapok fiber. The scopes of the experiment consist of a preparation of composite mixture samples of gypsum with kapok fiber with different composition and thickness, and the fabrication of a fire resistant testing furnace. A testing of samples which were conducted in accordance with the standard MS 1073: PART 2:1996.

Framework of risk assessment in relation to FGD-gypsum use as agricultural amendment

USDA-ARS?s Scientific Manuscript database

Due to the concerns by EPA of air pollution from coal fired power plants, the industry are building and retrofitting existing facilities to remove more impurities from the environment. Industry has introduced removal of fly ash contaminates before SO2 removal, allowing generation of FGD-gypsum with...

Design and basic properties of ternary gypsum-based mortars

NASA Astrophysics Data System (ADS)

Doleželová, M.; Vimmrová, A.

2017-10-01

Ternary mortars, prepared from gypsum, hydrated lime and three types of pozzolan were designed and tested. As a pozzolan admixture crushed ceramic, silica fume and granulated blast slag were used. The amount of pozzolans in the mixtures was determined according to molar weight of amorphous SiO2 in the material. The samples were stored under the water. The basic physical properties and mechanical properties were measured. The properties were compared with the properties of material without pozzolan. The best results in the water environment were achieved by the samples with silica fume.

Modelling of Fluidised Geomaterials: The Case of the Aberfan and the Gypsum Tailings Impoundment Flowslides

PubMed Central

Dutto, Paola; Stickle, Miguel Martin; Pastor, Manuel; Manzanal, Diego; Yague, Angel; Moussavi Tayyebi, Saeid; Lin, Chuan; Elizalde, Maria Dolores

2017-01-01

The choice of a pure cohesive or a pure frictional viscoplastic model to represent the rheological behaviour of a flowslide is of paramount importance in order to obtain accurate results for real cases. The principal goal of the present work is to clarify the influence of the type of viscous model—pure cohesive versus pure frictional—with the numerical reproduction of two different real flowslides that occurred in 1966: the Aberfan flowslide and the Gypsum tailings impoundment flowslide. In the present work, a depth-integrated model based on the v-pw Biot–Zienkiewicz formulation, enhanced with a diffusion-like equation to account for the pore pressure evolution within the soil mass, is applied to both 1966 cases. For the Aberfan flowslide, a frictional viscous model based on Perzyna viscoplasticity is considered, while a pure cohesive viscous model (Bingham model) is considered for the case of the Gypsum flowslide. The numerical approach followed is the SPH method, which has been enriched by adding a 1D finite difference grid to each SPH node in order to improve the description of the pore water evolution in the propagating mixture. The results obtained by the performed simulations are in agreement with the documentation obtained through the UK National Archive (Aberfan flowslide) and the International Commission of large Dams (Gypsum flowslide). PMID:28772924

Visible and Mid-Infrared Gypsum Optical Constants for Modeling of Martian Deposits

NASA Astrophysics Data System (ADS)

Roush, Ted L.; Esposito, Francesca; Rossmann, George R.; Colangeli, Luigi

2007-08-01

Introduction: Recent and on-going remote and in situ observations indicate that sulfates are present in significant abundances at various locations on Mars [1-7]. The Mars Reconnaissance Orbiter (MRO) imaging spectrometer (CRISM) is returning hyperspectral data at higher spatial resolution [8] than the OMEGA instrument on the Mars Express Mission [3]. Data from both OMEGA and CRISM have provided spectral evidence for the presence of gypsum and various hydrated sulfates on the Martian surface [e.g. 3-7] Thus, the optical properties of sulfates, in general, are of interest to quantitative interpretation of this increasing volume of remotely sensed data. This is because optical constants describe how a material interacts with electromagnetic radiation and represent the fundamental values used in radiative transfer calculations describing a variety of physical environments. Such environments include atmospheres where aerosols are present, planetary and satellite regoliths, and circumstellar dust clouds. Here we focus upon gypsum because of its applicability due to its identification on Mars. Also, gypsum is a mineral that is readily available in samples sizes that are suitable for study using a variety of spectral measurements. In the infrared (>5 μm) several studies reporting the optical constants of gypsum can be used in evaluating the approach used here. Most importantly, there is a general lack of data regarding the optical constants for gypsum at visible and mid-infrared wavelengths (0.4-5 μm) that are being observed by OMEGA and CRISM. Background: In the infrared, there have been several studies focused at determining the optical constants of gypsum using classical dispersion models [9-11]. These have used a variety of samples including; crystals, compressed pellets of pure materials, and grains suspended in a KBr matrix. Spectral measurements of gypsum, and other sulfates, have existed for about 100 years at visible and mid-infrared wavelengths (0.4-5 μm) [e

A new use of hydroxyapatite-based consolidant: cleaning and consolidation of stones in one step by reaction with gypsum crust

NASA Astrophysics Data System (ADS)

Molina Piernas, Eduardo; Rueda Quero, Lucia; Cultrone, Giuseppe; Ruiz Agudo, Encarnación

2015-04-01

The reaction between diammonium hydrogen phosphate (DAP) and calcite in the stone to form hydroxyapatite (HAP) had provided a new product to consolidate limestone or Ca-rich stones, for example sandstones with carbonatic cement. However, what does it happen with the stones without Ca-bearing compounds? Obviously, HAP cannot form. In the other hand, recent research about consolidation with DAP show a good interaction between carbonatic stones and HAP, improving their mechanical properties. For these reasons, we propose a new method for the consolidation of building stone capable of cleaning the gypsum crust and consolidating stones at the same time, based in the Ferroni-Dini method [1] and using DAP. Based on this method, we aim at obtaining a consolidating component reacting DAP (instead of ammonium carbonate) and the gypsum contained in the crust of weathered stones in polluted environments. As an advantage, we do not need to use barium hydroxide (the second step required in the Ferroni-Dini method), thereby reducing the time necessary to carry out the consolidation. Here, we report different tests to evaluate this new procedure. In a first set of experiments, a DAP solution was poured on a gypsum (dihydrate calcium sulphate) saturated solution and by monitoring the free calcium content of the solution using an ion-selective electrode we have evaluated the fluctuations in the content in calcium of the solution and the speed of the reaction. Once the reaction finished, we analyzed the solids formed to verify the formation of hydroxyapatite by FTIR and microRAMAN. The second test consisted in the alteration of limestone blocks with sulfuric acid to obtain a crust of gypsum and, after that, the samples were consolidated by means of cellulose compress soaked in DAP 3M during different reaction times (30 minutes, 1 hour and 4 hours, at controlled temperature -20 °C- and relative humidity -40% HR-). The samples were then analyzed by XRD, FTIR, microRAMAN and SEM-EDX to

Animal waste and FGD gypsum effects on bermudagrass and soil leachate nutrient contents

USDA-ARS?s Scientific Manuscript database

In previous experiments on newly relcaimed coal mine soils in northeastern Mississippi, applying poultry litter at 22.4 Mg ha-1 yr-1 enhanced bermudagrass (Cynodon dactylon L.) biomass and selected soil quality parameters. Additionally, co-application of 11.2 Mg ha-1 FGD gypsum and litter reduced so...

Gypsum as a best management practice for reducing P loss from agricultural fields

USDA-ARS?s Scientific Manuscript database

Phosphorus loss from agricultural fields fertilized with poultry litter (PL) may contribute to eutrophication of nearby rivers, lakes, and streams. It has been suggested that gypsum can be used as a soil amendment to reduce P loss from these fields. Also, a new USDA-NRCS National Conservation Practi...

The Affect of the Space Environment on the Survival of Halorubrum Chaoviator and Synechococcus (Nageli): Data from the Space Experiment OSMO on EXPOSE-R

NASA Technical Reports Server (NTRS)

Mancinelli, R. L.

2014-01-01

We have shown using ESA's Biopan facility flown in Earth orbit that when exposed to the space environment for 2 weeks the survival rate of Synechococcus (Nageli), a halophilic cyanobacterium isolated from the evaporitic gypsum-halite crusts that form along the marine intertidal, and Halorubrum chaoviator a member of the Halobacteriaceae isolated from an evaporitic NaCl crystal obtained from a salt evaporation pond, were higher than all other test organisms except Bacillus spores. These results led to the EXPOSE-R mission to extend and refine these experiments as part of the experimental package for the external platform space exposure facility on the ISS. The experiment was flown in February 2009 and the organisms were exposed to low-Earth orbit for nearly 2 years. Samples were either exposed to solar ultraviolet (UV)-radiation (lambda is greater than 110 nm or lambda is greater than 200 nm, cosmic radiation (dosage range 225-320 mGy), or kept in darkness shielded from solar UV-radiation. Half of each of the UV-radiation exposed samples and dark samples were exposed to space vacuum and half kept at 105 pascals in argon. Duplicate samples were kept in the laboratory to serve as unexposed controls. Ground simulation control experiments were also performed. After retrieval, organism viability was tested using Molecular Probes Live-Dead Bac-Lite stain and by their reproduction capability. Samples kept in the dark, but exposed to space vacuum had a 90 +/- 5% survival rate compared to the ground controls. Samples exposed to full UV-radiation for over a year were bleached and although results from Molecular Probes Live-Dead stain suggested approximately 10% survival, the data indicate that no survival was detected using cell growth and division using the most probable number method. Those samples exposed to attenuated UV-radiation exhibited limited survival. Results from of this study are relevant to understanding adaptation and evolution of life, the future of life

Synthesis of high-purity precipitated calcium carbonate during the process of recovery of elemental sulphur from gypsum waste.

PubMed

de Beer, M; Doucet, F J; Maree, J P; Liebenberg, L

2015-12-01

We recently showed that the production of elemental sulphur and calcium carbonate (CaCO3) from gypsum waste by thermally reducing the waste into calcium sulphide (CaS) followed by its direct aqueous carbonation yielded low-grade carbonate products (i.e. <90 mass% as CaCO3). In this study, we used the insight gained from our previous work and developed an indirect aqueous CaS carbonation process for the production of high-grade CaCO3 (i.e. >99 mass% as CaCO3) or precipitated calcium carbonate (PCC). The process used an acid gas (H2S) to improve the aqueous dissolution of CaS, which is otherwise poorly soluble. The carbonate product was primarily calcite (99.5%) with traces of quartz (0.5%). Calcite was the only CaCO3 polymorph obtained; no vaterite or aragonite was detected. The product was made up of micron-size particles, which were further characterised by XRD, TGA, SEM, BET and true density. Results showed that about 0.37 ton of high-grade PCC can be produced from 1.0 ton of gypsum waste, and generates about 0.19 ton of residue, a reduction of 80% from original waste gypsum mass to mass of residue that needs to be discarded off. The use of gypsum waste as primary material in replacement of mined limestone for the production of PPC could alleviate waste disposal problems, along with converting significant volumes of waste materials into marketable commodities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Arctic gypsum endoliths: a biogeochemical characterization of a viable and active microbial community

NASA Astrophysics Data System (ADS)

Ziolkowski, L. A.; Mykytczuk, N. C. S.; Omelon, C. R.; Johnson, H.; Whyte, L. G.; Slater, G. F.

2013-11-01

Extreme environmental conditions such as those found in the polar regions on Earth are thought to test the limits of life. Microorganisms living in these environments often seek protection from environmental stresses such as high UV exposure, desiccation and rapid temperature fluctuations, with one protective habitat found within rocks. Such endolithic microbial communities, which often consist of bacteria, fungi, algae and lichens, are small-scale ecosystems comprised of both producers and consumers. However, the harsh environmental conditions experienced by polar endolithic communities are thought to limit microbial diversity and therefore the rate at which they cycle carbon. In this study, we characterized the microbial community diversity, turnover rate and microbe-mineral interactions of a gypsum-based endolithic community in the polar desert of the Canadian high Arctic. 16S/18S/23S rRNA pyrotag sequencing demonstrated the presence of a diverse community of phototrophic and heterotrophic bacteria, archaea, algae and fungi. Stable carbon isotope analysis of the viable microbial membranes, as phospholipid fatty acids and glycolipid fatty acids, confirmed the diversity observed by molecular techniques and indicated that present-day atmospheric carbon is assimilated into the microbial community biomass. Uptake of radiocarbon from atmospheric nuclear weapons testing during the 1960s into microbial lipids was used as a pulse label to determine that the microbial community turns over carbon on the order of 10 yr, equivalent to 4.4 g C m-2 yr-1 gross primary productivity. Scanning electron microscopy (SEM) micrographs indicated that mechanical weathering of gypsum by freeze-thaw cycles leads to increased porosity, which ultimately increases the habitability of the rock. In addition, while bacteria were adhered to these mineral surfaces, chemical analysis by micro-X-ray fluorescence (μ-XRF) spectroscopy suggests little evidence for microbial alteration of minerals

Incorporation of gypsum waste in ceramic block production: Proposal for a minimal battery of tests to evaluate technical and environmental viability of this recycling process.

PubMed

Godinho-Castro, Alcione P; Testolin, Renan C; Janke, Leandro; Corrêa, Albertina X R; Radetski, Claudemir M

2012-01-01

Civil engineering-related construction and demolition debris is an important source of waste disposed of in municipal solid waste landfills. After clay materials, gypsum waste is the second largest contributor to the residential construction waste stream. As demand for sustainable building practices grows, interest in recovering gypsum waste from construction and demolition debris is increasing, but there is a lack of standardized tests to evaluate the technical and environmental viability of this solid waste recycling process. By recycling gypsum waste, natural deposits of gypsum might be conserved and high amounts of the waste by-product could be reused in the civil construction industry. In this context, this paper investigates a physical property (i.e., resistance to axial compression), the chemical composition and the ecotoxicological potential of ceramic blocks constructed with different proportions of clay, cement and gypsum waste, and assesses the feasibility of using a minimal battery of tests to evaluate the viability of this recycling process. Consideration of the results for the resistance to axial compression tests together with production costs revealed that the best formulation was 35% of plastic clay, 35% of non-plastic clay, 10% of Portland cement and 20% of gypsum waste, which showed a mean resistance of 4.64MPa. Energy dispersive X-ray spectrometry showed calcium and sulfur to be the main elements, while quartz, gypsum, ettringite and nacrite were the main crystalline compounds found in this formulation. Ecotoxicity tests showed that leachate from this formulation is weakly toxic toward daphnids and bacteria (EC(20%)=69.0 and 75.0, respectively), while for algae and fish the leachate samples were not toxic at the EC(50%) level. Overall, these results show that the addition of 20% of gypsum waste to the ceramic blocks could provide a viable substitute for clay in the ceramics industry and the tests applied in this study proved to be a useful tool

Triple Oxygen and Deuterium Isotopes in Gypsum Hydration Water for Quantitative Paleo-humidity Reconstructions

NASA Astrophysics Data System (ADS)

Gázquez, F.; Evans, N. P.; Herwartz, D.; Bauska, T. K.; Morellon, M.; Surma, J.; Moreno, A.; Staubwasser, M.; Valero-Garces, B. L.; Hodell, D. A.

2016-12-01

Variations in atmospheric relative humidity (RH) and precipitation may have driven major ecological and sociocultural changes during the Quaternary but quantitative proxies for RH are scarce and difficult to calibrate. The isotopic composition of lake water (δ17O, δ18O and δD, and derived d-excess and 17Oexcess) is sensitive to changes in atmospheric RH and temperature. Because 17Oexcess is less sensitive to temperature effects than the d-excess during evaporation, combining 17Oexces and d-excess provide information about the relative effects of humidity and temperature change in the hydrological cycle. Here we demonstrate how the isotope ratios of hydration water measured in gypsum from lake sediments can be used to reconstruct past changes in RH. We present stable isotopes of gypsum hydration water from two lake systems across the last deglaciation. In Lake Estanya (NE, Spain) the 17Oexcess and d-excess of the paleo-lake water indicates that evaporation of water during the Younger Dryas (ca. 12 kyr BP) occurred under RH conditions of 40-45%. Environmental humidity gradually increased over the Preboreal period and stabilised at 70-75% during the Holocene until present. In Lake Peten-Itza (Guatemala), the isotopic values of the paleo-lake waters during the Late Glacial can be explained by a lowering of atmospheric RH by 10% and cooling of temperature by 5oC compared with modern conditions. Our results demonstrate that the coupled measurement of 17Oexcess and d-excess of gypsum hydration water in lake sediments can provide a useful quantitative proxy for paleo-humidity.

The affect of the space environment on the survival of Halorubrum chaoviator and Synechococcus (Nägeli): data from the Space Experiment OSMO on EXPOSE-R

NASA Astrophysics Data System (ADS)

Mancinelli, R. L.

2015-01-01

We have shown using ESA's Biopan facility flown in Earth orbit that when exposed to the space environment for 2 weeks the survival rate of Synechococcus (Nägeli), a halophilic cyanobacterium isolated from the evaporitic gypsum-halite crusts that form along the marine intertidal, and Halorubrum chaoviator a member of the Halobacteriaceae isolated from an evaporitic NaCl crystal obtained from a salt evaporation pond, were higher than all other test organisms except Bacillus spores. These results led to the EXPOSE-R mission to extend and refine these experiments as part of the experimental package for the external platform space exposure facility on the ISS. The experiment was flown in February 2009 and the organisms were exposed to low-Earth orbit for nearly 2 years. Samples were either exposed to solar ultraviolet (UV)-radiation (λ > 110 nm or λ > 200 nm, cosmic radiation (dosage range 225-320 mGy), or kept in darkness shielded from solar UV-radiation. Half of each of the UV-radiation exposed samples and dark samples were exposed to space vacuum and half kept at 105 pascals in argon. Duplicate samples were kept in the laboratory to serve as unexposed controls. Ground simulation control experiments were also performed. After retrieval, organism viability was tested using Molecular Probes Live-Dead Bac-Lite stain and by their reproduction capability. Samples kept in the dark, but exposed to space vacuum had a 90 +/- 5% survival rate compared to the ground controls. Samples exposed to full UV-radiation for over a year were bleached and although results from Molecular Probes Live-Dead stain suggested ~10% survival, the data indicate that no survival was detected using cell growth and division using the most probable number method. Those samples exposed to attenuated UV-radiation exhibited limited survival. Results from of this study are relevant to understanding adaptation and evolution of life, the future of life beyond earth, the potential for interplanetary

Flue gas desulfurization gypsum: Its effectiveness as an alternative bedding material for broiler production

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization gypsum (FGDG) may be a viable low-cost alternative bedding material for broiler production. In order to evaluate FGD gypsum’s viability, three consecutive trials were conducted to determine its influence on live performance (body weight, feed consumption, feed efficiency, an...

Application of gypsum to control P runoff from poultry litter fertilization of pasture

USDA-ARS?s Scientific Manuscript database

This paper will discuss the utilization of gypsum (CaSO4 .2H2O) to reduce P losses from surface runoff when poultry litter is used as a fertilizer source in agriculture. Utilization of poultry litter as a fertilizer source is common in regions with intense poultry production. While poultry litter ...

To the Die Smartly: Heavy Ion Testing of PEMs on COTS Boards Through the Plastic

NASA Technical Reports Server (NTRS)

Wert, J. L.; Normand, E.; Oberg, D. L.; Stevens, L.; Blumer, J.; Fisher, E.; Wode, G.

1999-01-01

Seven commercial off the shelf (COTS) boards containing electronic devices (all in plastic packages, PEMS), under consideration for use in a spacecraft subsystem, were exposed to beams of very high energy ions at the National Superconducting Cyclotron Laboratory (MSU). The ion energies were high enough that an entire board could be exposed in air, and it could still penetrate through the plastic and reach the silicon die. A total of about 300 runs were made, and for each, the LET of the ion entering the silicon die had to be determined, based on the thickness of the plastic lid and the thickness of overlaying materials (e.g., aluminum degraders). Single event latchup (SEL) and functional interrupt (SEFI) were determined during each run, the SEFI by means of simple programs being continuously written to and read from the boards to monitor functionality, while each part was being exposed to the heavy ions.

Developing biodiversity indicators on a stakeholders' opinions basis: the gypsum industry Key Performance Indicators framework.

PubMed

Pitz, Carline; Mahy, Grégory; Vermeulen, Cédric; Marlet, Christine; Séleck, Maxime

2016-07-01

This study aims to establish a common Key Performance Indicators (KPIs) framework for reporting about the gypsum industry biodiversity at the European level. In order to integrate different opinions and to reach a consensus framework, an original participatory process approach has been developed among different stakeholder groups: Eurogypsum, European and regional authorities, university scientists, consulting offices, European and regional associations for the conservation of nature, and the extractive industry. The strategy is developed around four main steps: (1) building of a maximum set of indicators to be submitted to stakeholders based on the literature (Focus Group method); (2) evaluating the consensus about indicators through a policy Delphi survey aiming at the prioritization of indicator classes using the Analytic Hierarchy Process method (AHP) and of individual indicators; (3) testing acceptability and feasibility through analysis of Environmental Impact Assessments (EIAs) and visits to three European quarries; (4) Eurogypsum final decision and communication. The resulting framework contains a set of 11 indicators considered the most suitable for all the stakeholders. Our KPIs respond to European legislation and strategies for biodiversity. The framework aims at improving sustainability in quarries and at helping to manage biodiversity as well as to allow the creation of coherent reporting systems. The final goal is to allow for the definition of the actual biodiversity status of gypsum quarries and allow for enhancing it. The framework is adaptable to the local context of each gypsum quarry.

Histological Comparison in Rats between Carbonate Apatite Fabricated from Gypsum and Sintered Hydroxyapatite on Bone Remodeling

PubMed Central

Ayukawa, Yasunori; Suzuki, Yumiko; Tsuru, Kanji; Koyano, Kiyoshi; Ishikawa, Kunio

2015-01-01

Carbonate apatite (CO3Ap), the form of apatite found in bone, has recently attracted attention. The purpose of the present study was to histologically evaluate the tissue/cellular response toward the low-crystalline CO3Ap fabricated using a dissolution-precipitation reaction with set gypsum as a precursor. When set gypsum was immersed in a 100°C 1 mol/L Na3PO4 aqueous solution for 24 h, the set gypsum transformed into CO3Ap. Both CO3Ap and sintered hydroxyapatite (s-HAp), which was used as a control, were implanted into surgically created tibial bone defects of rats for histological evaluation. Two and 4 weeks after the implantation, histological sections were created and observed using light microscopy. The CO3Ap granules revealed both direct apposition of the bone matrix by osteoblasts and osteoclastic resorption. In contrast, the s-HAp granules maintained their contour even after 4 weeks following implantation which implied that there was a lack of replacement into the bone. The s-HAp granules were sometimes encapsulated with fibrous tissue, and macrophage polykaryon was occasionally observed directly apposed to the implanted granules. From the viewpoint of bone remodeling, the CO3Ap granules mimicked the bone matrix, suggesting that CO3Ap may be an appropriate bone substitute. PMID:26504813

Clay stabilization by using gypsum and paddy husk ash with reference to UCT and CBR value

NASA Astrophysics Data System (ADS)

Roesyanto; Iskandar, R.; Hastuty, I. P.; Dianty, W. O.

2018-02-01

Clays that have low shear strength need to be stabilized in order to meet the technical requirements to serve as a subgrade material. One of the usual soil stabilization methods is by adding chemicals such as Portland cement, lime, and bitumen. The clay stabilization research was done by adding gypsum and paddy husk ash. The research goals were to find out the value of engineering properties of clay due to the addition of 2% gypsum and 2% - 15% paddy husk ash. The soil was classified as Clay - Low Plasticity (CL) based on USCS and was classified as A-7-6 (10) based on AASHTO classification system. The UCT value of original soil was 1.41 kg/cm2. While the CBR soaked and unsoaked values of original soil were 4.41% and 6.23% respectively. The research results showed the addition of paddy husk ash decreased the value of unconfined compressive strength as well as CBR. The stabilized soil by 2% gypsum and 0% paddy husk ash gave maximum UCT value of 1.67 kg/cm2, while the maximum value of CBR were found 6.71% for CBR soaked and 8.00% for CBR unsoaked. The addition of paddy husk ash did not alter the soil classification according to AASHTO or USCS, even degrade the engineering properties of original soil.

A Method for Optimizing Lightweight-Gypsum Design Based on Sequential Measurements of Physical Parameters

NASA Astrophysics Data System (ADS)

Vimmrová, Alena; Kočí, Václav; Krejsová, Jitka; Černý, Robert

2016-06-01

A method for lightweight-gypsum material design using waste stone dust as the foaming agent is described. The main objective is to reach several physical properties which are inversely related in a certain way. Therefore, a linear optimization method is applied to handle this task systematically. The optimization process is based on sequential measurement of physical properties. The results are subsequently point-awarded according to a complex point criterion and new composition is proposed. After 17 trials the final mixture is obtained, having the bulk density equal to (586 ± 19) kg/m3 and compressive strength (1.10 ± 0.07) MPa. According to a detailed comparative analysis with reference gypsum, the newly developed material can be used as excellent thermally insulating interior plaster with the thermal conductivity of (0.082 ± 0.005) W/(m·K). In addition, its practical application can bring substantial economic and environmental benefits as the material contains 25 % of waste stone dust.

Board Saver for Use with Developmental FPGAs

NASA Technical Reports Server (NTRS)

Berkun, Andrew

2009-01-01

A device denoted a board saver has been developed as a means of reducing wear and tear of a printed-circuit board onto which an antifuse field programmable gate array (FPGA) is to be eventually soldered permanently after a number of design iterations. The need for the board saver or a similar device arises because (1) antifuse-FPGA design iterations are common and (2) repeated soldering and unsoldering of FPGAs on the printed-circuit board to accommodate design iterations can wear out the printed-circuit board. The board saver is basically a solderable/unsolderable FPGA receptacle that is installed temporarily on the printed-circuit board. The board saver is, more specifically, a smaller, square-ring-shaped, printed-circuit board (see figure) that contains half via holes one for each contact pad along its periphery. As initially fabricated, the board saver is a wider ring containing full via holes, but then it is milled along its outer edges, cutting the via holes in half and laterally exposing their interiors. The board saver is positioned in registration with the designated FPGA footprint and each via hole is soldered to the outer portion of the corresponding FPGA contact pad on the first-mentioned printed-circuit board. The via-hole/contact joints can be inspected visually and can be easily unsoldered later. The square hole in the middle of the board saver is sized to accommodate the FPGA, and the thickness of the board saver is the same as that of the FPGA. Hence, when a non-final FPGA is placed in the square hole, the combination of the non-final FPGA and the board saver occupy no more area and thickness than would a final FPGA soldered directly into its designated position on the first-mentioned circuit board. The contact leads of a non-final FPGA are not bent and are soldered, at the top of the board saver, to the corresponding via holes. A non-final FPGA can readily be unsoldered from the board saver and replaced by another one. Once the final FPGA design

Potential of soil amendments (Biochar and Gypsum) in increasing water use efficiency of Abelmoschus esculentus L. Moench

PubMed Central

Batool, Aniqa; Taj, Samia; Rashid, Audil; Khalid, Azeem; Qadeer, Samia; Saleem, Aansa R.; Ghufran, Muhammad A.

2015-01-01

Water being an essential component for plant growth and development, its scarcity poses serious threat to crops around the world. Climate changes and global warming are increasing the temperature of earth hence becoming an ultimate cause of water scarcity. It is need of the day to use potential soil amendments that could increase the plants’ resistance under such situations. Biochar and gypsum were used in the present study to improve the water use efficiency (WUE) and growth of Abelmoschus esculentus L. Moench (Lady’s Finger). A 6 weeks experiment was conducted under greenhouse conditions. Stress treatments were applied after 30 days of sowing. Plant height, leaf area, photosynthesis, transpiration rate (Tr), stomatal conductance and WUE were determined weekly under stressed [60% field capacity (F.C.)] and non-stressed (100% F.C.) conditions. Stomatal conductance and Tr decreased and reached near to zero in stressed plants. Stressed plants also showed resistance to water stress upto 5 weeks and gradually perished at sixth week. On the other hand, WUE improved in stressed plants containing biochar and gypsum as compared to untreated plants. Biochar alone is a better strategy to promote plant growth and WUE specifically of A. esculentus, compared to its application in combination with gypsum. PMID:26442046

Microbial Volatile Organic Compound Emissions from Stachybotrys chartarum growing on Gypsum Wallboard and Ceiling tile

EPA Science Inventory

This study compared seven toxigenic strains of S. chartarum found in water-damaged buildings to characterize the microbial volatile organic compound (MVOC) emissions profile while growing on gypsum wallboard (W) and ceiling tile (C) coupons. The inoculated coupons with their sub...

Gypsum scarps and asymmetric fluvial valleys in evaporitic terrains. The role of river migration, landslides, karstification and lithology (Ebro River, NE Spain)

NASA Astrophysics Data System (ADS)

Guerrero, J.; Gutiérrez, F.

2017-11-01

Most of the Spanish fluvial systems excavated in Tertiary evaporitic gypsum formations show asymmetric valleys characterized by a stepped sequence of fluvial terraces on one valley flank and kilometric-long and > 100-m high prominent river scarp on the opposite side of the valley. Scarp undermining by the continuous preferential lateral migration of the river channel toward the valley margin leads to vertical to overhanging unstable slopes affected by a large number of slope failures that become the main geological hazard for villages located at the toe of the scarps. Detailed mapping of the gypsum scarps along the Ebro and Huerva Rivers gypsum scarps demonstrates that landslides and lateral spreading processes are predominant when claystones crop out at the base of the scarp, while rockfalls and topples become the dominant movement in those reaches where the rock mass is mainly constituted by evaporites. The dissolution of gypsum nodules, seasonal swelling and shrinking, and dispersion processes contribute to a decrease in the mechanical strength of claystones. The existence of dissolution-enlarged joints, sinkholes, and severely damaged buildings at the toe of the scarp from karstic subsidence demonstrates that the interstratal karstification of evaporites becomes a triggering factor in the instability of the rock mass. The genesis of asymmetric valleys and river gypsum scarps in the study area seem to be caused by the random migration of the river channel in the absence of lateral tilting related to tectonics or dissolution-induced subsidence. Once the scarp is developed, its preservation depends on the physicochemical properties of the substratum, the ratio between bedrock erosion and river incision rates, and climatic conditions that favour runoff erosion versus dissolution.

Gypsum (CaSO4·2H2O) Scaling on Polybenzimidazole and Cellulose Acetate Hollow Fiber Membranes under Forward Osmosis

PubMed Central

Chen, Si Cong; Su, Jincai; Fu, Feng-Jiang; Mi, Baoxia; Chung, Tai-Shung

2013-01-01

We have examined the gypsum (CaSO4·2H2O) scaling phenomena on membranes with different physicochemical properties in forward osmosis (FO) processes. Three hollow fiber membranes made of (1) cellulose acetate (CA), (2) polybenzimidazole (PBI)/polyethersulfone (PES) and (3) PBI-polyhedral oligomeric silsesquioxane (POSS)/polyacrylonitrile (PAN) were studied. For the first time in FO processes, we have found that surface ionic interactions dominate gypsum scaling on the membrane surface. A 70% flux reduction was observed on negatively charged CA and PBI membrane surfaces, due to strong attractive forces. The PBI membrane surface also showed a slightly positive charge at a low pH value of 3 and exhibited a 30% flux reduction. The atomic force microscopy (AFM) force measurements confirmed a strong repulsive force between gypsum and PBI at a pH value of 3. The newly developed PBI-POSS/PAN membrane had ridge morphology and a contact angle of 51.42° ± 14.85° after the addition of hydrophilic POSS nanoparticles and 3 min thermal treatment at 95 °C. Minimal scaling and an only 1.3% flux reduction were observed at a pH value of 3. Such a ridge structure may reduce scaling by not providing a locally flat surface to the crystallite at a pH value of 3; thus, gypsum would be easily washed away from the surface. PMID:24957062

Climatic control on the growth of gigantic gypsum crystals within hypogenic caves (Naica mine, Mexico)?

NASA Astrophysics Data System (ADS)

Garofalo, Paolo S.; Fricker, Mattias B.; Günther, Detlef; Forti, Paolo; Mercuri, Anna-Maria; Loreti, Mara; Capaccioni, Bruno

2010-01-01

Three hypogenic caves within the Naica mine of Mexico ( Cueva de los Cristales — CLC, Ojo de la Reina — OR, and Cueva de las Velas — CLV) host spectacular gypsum crystals up to 11 m in length. These caves are close to another shallow cave of the area ( Cueva de las Espadas — CLE), with which they cover a 160 m-deep vertical section of the local drainage basin. Similar to other hypogenic caves, all these caves lack a direct connection with the land surface and should be unrelated with climate. A record of multi-technique fluid inclusion data and pollen spectra from cave and mine gypsum indicates surprisingly that climatic changes occurring at Naica could have controlled fluid composition in these caves, and hence crystal growth. Microthermometry and LA-ICP-Mass Spectrometry of fluid inclusions indicate that the shallow, chemically peculiar, saline fluid (up to 7.7 eq. wt.%NaCl) of CLE could have formed from evaporation, during a dry and hot climatic period. The fluid of the deep caves was instead of low salinity (˜ 3.5 eq. wt.% NaCl) and chemically homogeneous, and was poorly affected by evaporation. We propose that mixing of these two fluids, generated at different depths of the Naica drainage basin, determined the stable supersaturation conditions for the gigantic gypsum crystals to grow. Fluid mixing was controlled by the hydraulic communication between CLE and the other deep caves, and must have taken place during cycles of warm-dry and fresh-wet climatic periods, which are known to have occurred in the region. Pollen grains from a 35 ka-old gypsum crystal of CLC corresponds to a fairly homogenous catchment basin made of a mixed broadleaf wet forest, which suggests precipitation during a fresh-wet climatic period and confirms our interpretation of the fluid inclusion data. The unusual combination of geological and geochemical factors of Naica suggests that other hypogenic caves found elsewhere may not host similar crystals. However, this work shows that

Use of Flue Gas Desulfurization (FGD) Gypsum as a Heavy Metal Stabilizer in Contaminated Soils

EPA Science Inventory

Flue Gas Desulfurization (FGD) gypsum is a synthetic by-product generated from the flue gas desulfurization process in coal power plants. It has several beneficial applications such as an ingredient in cement production, wallboard production and in agricultural practice as a soil...

Nucleation and growth of the Naica giant gypsum crystals.

PubMed

Otálora, Fermín; García-Ruiz, JuanMa

2014-04-07

The Cave of Giant Crystals in the Naica mine (Mexico) is one of the most amazing displays of mineral beauty ever created in nature. In addition to the colossal crystals of gypsum, which in some cases exceed eleven meters in length and one meter in thickness, the scenery fashioned by the crystalline beams that thrust through the darkness of the cave from floor to ceiling with a luster like moonlight is a unique example of harmony based on crystal symmetry. We review the crystallogenesis of this remarkable and challenging phenomenon of mineralization near equilibrium that can be used to teach the basics of nucleation and crystal growth.

Laboratory and environmental decay of wood–plastic composite boards: flexural properties

Treesearch

Rebecca Ibach; Marek Gnatowski; Grace Sun; Jessie Glaeser; Mathew Leung; John Haight

2017-01-01

The flexural properties of wood–plastic composite (WPC) deck boards exposed to 9.5 years of environmental decay in Hilo, Hawaii, were compared to samples exposed to moisture and decay fungi for 12 weeks in the laboratory, to establish a correlation between sample flexural properties and calculated void volume. Specimens were tested for flexural strength and modulus,...

Assessment of Mercury in Soils, Crops, Earthworms, and Water when Soil is Treated with Gypsum

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization (FGD) gypsum from fossil fuel combustion has many potential uses in agriculture, but there is concern about the potential environmental effects of its elevated mercury (Hg) concentration. The wet limestone scrubbing process that removes sulfur from flue gas (and produces gyp...

Potential adherence of gypsum to forage as a consideration for excessive ingestion by ruminates

USDA-ARS?s Scientific Manuscript database

Gypsum (calcium sulfate dihydrate, CaSO4•2H2O) has long been used in agriculture to improve soils and crop production and its use has recently been encouraged by the USDA NRCS for soil conservation through a new National Conservation Practice Standard: Code 333. However, there is concern regarding ...

FGD gypsum application: Impacts on soil P from city parks in the Tampa area

USDA-ARS?s Scientific Manuscript database

Controlling excessive P loss from agricultural fields has become a major issue in recent years. However, managed city parks may also contribute to P loss. Thus, a study was conducted at three different city parks located in the Tampa Area to evaluate the use of FGD gypsum as an amendment to reduce w...

Soil test and bermudagrass forage yield responses to animal waste and FGD gypsum ammendments

USDA-ARS?s Scientific Manuscript database

Knowledge of soil and plant responses to animal or industrial byproducts is needed for effective use of these potential amendments on reclaimed mine soil. This study compared seven treatments of 11.2 Mg ha-1 flue gas desulfurized (FGD) gypsum (control), 896 kg ha-1 NPK fertilizer (13-13-13), 22.4 M...

Remediation of saline-sodic soil with flue gas desulfurization gypsum in a reclaimed tidal flat of southeast China.

PubMed

Mao, Yumei; Li, Xiaping; Dick, Warren A; Chen, Liming

2016-07-01

Salinization and sodicity are obstacles for vegetation reconstruction of coastal tidal flat soils. A study was conducted with flue gas desulfurization (FGD)-gypsum applied at rates of 0, 15, 30, 45 and 60Mg/ha to remediate tidal flat soils of the Yangtze River estuary. Exchangeable sodium percentage (ESP), exchangeable sodium (ExNa), pH, soluble salt concentration, and composition of soluble salts were measured in 10cm increments from the surface to 30cm depth after 6 and 18months. The results indicated that the effect of FGD-gypsum is greatest in the 0-10cm mixing soil layer and 60Mg/ha was the optimal rate that can reduce the ESP to below 6% and decrease soil pH to neutral (7.0). The improvement effect was reached after 6months, and remained after 18months. The composition of soluble salts was transformed from sodic salt ions mainly containing Na(+), HCO3(-)+CO3(2-) and Cl(-) to neutral salt ions mainly containing Ca(2+) and SO4(2-). Non-halophyte plants were survived at 90%. The study demonstrates that the use of FGD-gypsum for remediating tidal flat soils is promising. Copyright © 2016. Published by Elsevier B.V.

[Determination of multi-element contents in gypsum by ICP-AES].

PubMed

Guo, Zhong-bao; Bai, Yong-zhi; Cui, Jin-hua; Mei, Yi-fei; Ma, Zhen-zhu

2014-08-01

The content of multi-element in gypsum was determined by ICP-AES. The sample was pretreated by acid-soluble method or alkali-fusion method. Acid-soluble method is suitable for the determination of CaO, SOs, Al2O3, Fe2O3, MgO, K2O, Na2O, TiO2, P2O5, MnO, SrO and BaO. Alkali-fusion method is suitable for the determination of CaO, SO3, SiO2, Al2O3, Fe2O3, MgO, TiO2, P2O5, MnO, SrO, BaO and B2O3. Different series standard solutions were prepared considering the properties and content of elements and solution matrix. The limit of detection and quantification were confirmed for each element under their best analysis spectral lines. The recoveries of the two pretreatment methods were from 93% to 110%, besides that for TiO2 was 81%-87% as pretreated by acid-soluble method. All RSDs (n=6) of tests were from 0.70%-3.42%. The accuracies of CaO and SO3 with ICP-AES method were less than the chemical analysis method. The determination of CaO and SO3 with ICP-AES method is only suitable for the case of low accuracy requirement. The results showed that the method can be used for the determination of multi-element contents in gypsum, with simple operation, fast analysis and reliable results. Total elements can be analysed with both acid-soluble method and alkali-fusion method.

Potential Agricultural Uses of Flue Gas Desulfurization Gypsum in the Northern Great Plains

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

DeSutter, T.M.; Cihacek, L.J.

2009-07-15

Flue gas desulfurization gypsum (FGDG) is a byproduct from the combustion of coal for electrical energy production. Currently, FGDG is being produced by 15 electrical generating stations in Alabama, Florida, Indiana, Iowa, Kentucky, Ohio, North Carolina, South Carolina, Tennessee, Texas, and Wisconsin. Much of this byproduct is used in the manufacturing of wallboard. The National Network for Use of FGDG in Agriculture was initiated to explore alternative uses of this byproduct. In the northern Great Plains (North Dakota, South Dakota, and Montana), FGDG has the potential to be used as a Ca or S fertilizer, as an acid soil ameliorant,more » and for reclaiming or mitigating sodium-affected soils. Greater than 1.4 million Mg of FGDG could initially be used in these states for these purposes. Flue gas desulfurization gypsum can be an agriculturally important resource for helping to increase the usefulness of problem soils and to increase crop and rangeland production. Conducting beneficial use audits would increase the public awareness of this product and help identify to coal combustion electrical generating stations the agriculturally beneficial outlets for this byproduct.« less

Utility of hyperspectral imagers in the mining industry: Italy's gypsum reserves

NASA Astrophysics Data System (ADS)

Wilson, Janette H.; Greenberger, Rebecca N.

2014-05-01

The mining industry is plagued with socioeconomic and safety roadblocks with not many solutions in the midst of a demanding market. As more and more geologic research using hyperspectral technology has been performed, along with an affordable price point for commercial use of hyperspectral technology, the benefits of hyperspectral imaging to the mining industry has become apparent. This study identifies the key areas of use for hyperspectral imaging in the mining industry through a case study of gypsum mine samples obtained from a mine in central Tuscany.

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 .

Permeability of gypsum samples dehydrated in air

NASA Astrophysics Data System (ADS)

Milsch, Harald; Priegnitz, Mike; Blöcher, Guido

2011-09-01

We report on changes in rock permeability induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air (dry) for up to 800 h at ambient pressure and temperatures between 378 and 423 K. Subsequently, the reaction kinetics, so induced changes in porosity, and the concurrent evolution of sample permeability were constrained. Weighing the heated samples in predefined time intervals yielded the reaction progress where the stoichiometric mass balance indicated an ultimate and complete dehydration to anhydrite regardless of temperature. Porosity showed to continuously increase with reaction progress from approximately 2% to 30%, whilst the initial bulk volume remained unchanged. Within these limits permeability significantly increased with porosity by almost three orders of magnitude from approximately 7 × 10-19 m2 to 3 × 10-16 m2. We show that - when mechanical and hydraulic feedbacks can be excluded - permeability, reaction progress, and porosity are related unequivocally.

Flue-gas desulfurization gypsum effects on urea-degrading bacteria and ammonia volatilization from broiler litter.

USDA-ARS?s Scientific Manuscript database

A major concern of the broiler industry is the volatilization of ammonia (NH3) from the mixture of bedding material and broiler excretion that covers the floor of broiler houses. Gypsum has been proposed as a litter amendment to reduce NH3 volatilization, but reports of NH3 abatement vary among stu...

Calcium Sulfates at Gale Crater and Limitations on Gypsum Stability

NASA Technical Reports Server (NTRS)

Vantiman, D. T.; Martinez, G. M.; Rampe, E. B.; Bristow, T. F.; Blake, D. F.; Yen, A. H.; Ming, D. W.; Rapin, W.; Meslin, P. -Y.; Morookian, J. M.;

Impact of Leaching Conditions on Constituents Release from Flue Gas Desulfurization Gypsum (FGDG) and FGDG-Soil Mixture

EPA Science Inventory

The interest in using Flue Gas Desulfurization Gypsum(FGDG) has increased recently. This study evaluates the leaching characteristics of trace elements in "modern" FGDG (produced after fly ash removal) and FGDG-mixed soil (SF) under different environmental conditions using rece...

Investigation of Dynamic Crack Coalescence Using a Gypsum-Like 3D Printing Material

NASA Astrophysics Data System (ADS)

Jiang, Chao; Zhao, Gao-Feng; Zhu, Jianbo; Zhao, Yi-Xin; Shen, Luming

2016-10-01

Dynamic crack coalescence attracts great attention in rock mechanics. However, specimen preparation in experimental study is a time-consuming and difficult procedure. In this work, a gypsum-like material by powder bed and inkjet 3D printing technique was applied to produce specimens with preset cracks for split Hopkinson pressure bar (SHPB) test. From micro X-ray CT test, it was found that the 3D printing technique could successfully prepare specimens that contain preset cracks with width of 0.2 mm. Basic mechanical properties of the 3D printing material, i.e., the elastic modulus, the Poisson's ratio, the density, the compressive strength, the indirect tensile strength, and the fracture toughness, were obtained and reported. Unlike 3D printed specimens using polylactic acid, these gypsum-like specimens can produce failure patterns much closer to those observed in classical rock mechanical tests. Finally, the dynamic crack coalescence of the 3D printed specimens with preset cracks were captured using a high-speed camera during SHPB tests. Failure patterns of these 3D printed specimens are similar to the specimens made by Portland cement concrete. Our results indicate that sample preparation by 3D printing is highly competitive due to its quickness in prototyping, precision and flexibility on the geometry, and high material homogeneity.

Regional transport of a chemically distinctive dust: Gypsum from White Sands, New Mexico (USA)

NASA Astrophysics Data System (ADS)

White, Warren H.; Hyslop, Nicole P.; Trzepla, Krystyna; Yatkin, Sinan; Rarig, Randy S.; Gill, Thomas E.; Jin, Lixin

2015-03-01

The White Sands complex, a National Monument and adjoining Missile Range in southern New Mexico, occupies the dry bed of an ice-age lake where an active gypsum dunefield abuts erodible playa sediments. Aerosols entrained from White Sands are sometimes visible on satellite images as distinct, light-colored plumes crossing the Sacramento Mountains to the east and northeast. The IMPROVE network (Interagency Monitoring of PROtected Visual Environments) operates long-term aerosol samplers at two sites east of the Sacramento range. In recent years a spring pulse of sulfate aerosol has appeared at these sites, eclipsing the regional summer peak resulting from atmospheric reactions of sulfur dioxide emissions. A significant fraction of this spring sulfate is contributed by gypsum and other salts from White Sands, with much of the sulfur in coarse particles and concentrations of calcium and strontium above regional levels. The increase in these gypsiferous species coincides with a drought following a period of above-average precipitation. White Sands and the IMPROVE samplers together provide a natural laboratory: a climatically sensitive dust source that is both well characterized and chemically distinct from its surroundings, with a signature that remains identifiable at long-term observatories 100-200 km downwind.

Friction evaluation of unpaved, gypsum-surface runways at Northrup Strip, White Sands Missile Range, in support of Space Shuttle Orbiter landing and retrieval operations

NASA Technical Reports Server (NTRS)

Yager, T. J.; Horne, W. B.

1980-01-01

Friction measurement results obtained on the gypsum surface runways at Northrup Strip, White Sands Missile Range, N. M., using an instrumented tire test vehicle and a diagonal braked vehicle, are presented. These runways were prepared to serve as backup landing and retrieval sites to the primary sites located at Dryden Flight Research Center for shuttle orbiter during initial test flights. Similar friction data obtained on paved and other unpaved surfaces was shown for comparison and to indicate that the friction capability measured on the dry gypsum surface runways is sufficient for operations with the shuttle orbiter and the Boeing 747 aircraft. Based on these ground vehicle friction measurements, estimates of shuttle orbiter and aircraft tire friction performance are presented and discussed. General observations concerning the gypsum surface characteristics are also included and several recommendations are made for improving and maintaining adequate surface friction capabilities prior to the first shuttle orbiter landing.

Age and speleogenesis of epigenic gypsum caves in the northern Apennines (Italy)

NASA Astrophysics Data System (ADS)

Columbu, Andrea; Chiarini, Veronica; De Waele, Jo; Drysdale, Russell; Forti, Paolo; Hellstrom, John; Woodhead, Jon

2016-04-01

Triassic and Messinian gypsum beds host the majority of the caves in the eastern flank of the northern Apennines. To date, more than six hundreds voids have been mapped, including the longest known epigenic gypsum cave system in the world (Spipola-Acquafredda, ~11 km of tunnels) (De Waele et al., 2013). Superimposed caves are typically sub-horizontal (Klimchouk, 2000) and connected through vertical shafts, reflecting the palaeo base-level variations. When preserved, river terraces at the surface lie at the same palaeo altitude of the base level and horizontal cave passages. Notwithstanding the well-known geology of the area known (Vai and Martini, 2001), the age of these caves has been greatly underestimated in the past. Considering the rapid dissolution of the gypsum and uplifting of the area, the start of speleogenesis activity was considered to have occurred during the last glacial age. The age of karst voids can be only indirectly estimated by the dating of the infilling sediments. U-Th dating on carbonate speleothems provides high-precision and accurate ages (Hellstrom, 2003; Scholz and Hoffmann, 2008). We thus applied this methodology to 20 speleothems coming from 14 different caves belonging to the Monte Tondo, Spipola Acquafredda, Castelnuovo, Stella-Rio Basino and Brisighella systems. The results show that: i) caves were forming since at least ~300 ka; ii) the peak of speleogenesis was reached during relatively cold climate stages, when rivers formed terraces at the surface and aggradation caused paragenesis in the stable cave levels (Columbu et al., 2015). Besides the significant contribution to the understanding of the Apennines evaporite karst evolution, this study (and its further advancement) may also refine knowledge of the local vs regional uplifting rates and base-level variations since the late Pleistocene (Wegmann and Pazzaglia, 2009). References Columbu, A., De Waele, J., Forti, P., Montagna, P., Picotti, V., Pons-Branchu, E., Hellstrom, J

Relative Shock Effects in Mixed Powders of Calcite, Gypsum, and Quartz: A Calibration Scheme from Shock Experiments

NASA Technical Reports Server (NTRS)

Bell, Mary S.

2009-01-01

The shock behavior of calcite and gypsum is important in understanding the Cretaceous/Tertiary event and other terrestrial impacts that contain evaporite sediments in their targets. Most interest focuses on issues of devolatilization to quantify the production of CO2 or SO2 to better understand their role in generating a temporary atmosphere and its effects on climate and biota [e.g., papers in 1,2,3,4]. Devolatilization of carbonate is also important because the dispersion and fragmentation of ejecta is strongly controlled by the expansion of large volumes of gas during the impact process as well [5,6]. Shock recovery experiments for calcite yield seemingly conflicting results: early experimental devolatilization studies [7,8,9] suggested that calcite was substantially outgassed at 30 GPa (> 50%). However, the recent petrographic work of [10,11,12] presented evidence that essentially intact calcite is recovered from 60 GPa experiments. [13] reported results of shock experiments on anhydrite, gypsum, and mixtures of those phases with silica. Their observations indicate little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another (preliminary) report of shock experiments on calcite, anhydrite, and gypsum, [14] observe calcite recrystallization when shock loaded at 61 GPa, only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa. [15] shock loaded anhydrite and quartz to a peak pressure of 60 GPa. All of the quartz grains were trans-formed to glass and the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggest that recrystallization of anhydrite grains is the result of a solid state transformation. [16] reanalyzed the calcite and anhydrite shock

Optically stimulated luminescence dosimetry with gypsum wallboard (drywall).

PubMed

Thompson, Jeroen W; Burdette, Kevin E; Inrig, Elizabeth L; Dewitt, Regina; Mistry, Rajesh; Rink, W Jack; Boreham, Douglas R

2010-09-01

Gypsum wallboard (drywall) represents an attractive target for retrospective dosimetry by optically stimulated luminescence (OSL) in the event of a radiological accident or malicious use of nuclear material. In this study, wallboard is shown to display a radiation-induced luminescence signal (RIS) as well as a natural background signal (NS), which is comparable in intensity to the RIS. Excitation and emission spectra show that maximum luminescence intensity is obtained for stimulation with blue light-emitting diodes (470 nm) and for detection in the ultraviolet region (290-370 nm). It is necessary to decrease the optical stimulation power dramatically in order to adequately separate the RIS from the interfering background signal. The necessary protocols are developed for accurately measuring the absorbed dose as low as 500 mGy and demonstrate that the RIS decays logarithmically with storage time, with complete erasure expected within 1-4 d.

Evaluation of flue-gas desulfurization gypsum in poultry litter as a substrate component for greenhouse horticultural crops

USDA-ARS?s Scientific Manuscript database

A study was conducted to evaluate the growth response and consumer preference of three plant species to substrate blends containing flue gas desulfurization gypsum (FGDG). Substrate blends used in this study were derived from a previous experiment that evaluated the use of FGD Gas a bedding material...

Self-disinfecting Alginate vs Conventional Alginate: Effect on Surface Hardness of Gypsum Cast-An in vitro Study.

PubMed

Madhavan, Ranjith; George, Navia; Thummala, Niharika R; Ravi, S V; Nagpal, Ajay

2017-11-01

For the construction of any dental prosthesis, accurate impressions are necessary. Hence, we undertook the present study to evaluate and compare the surface hardness of gypsum casts poured from impressions made using conventional alginate and self-disinfecting alginate. A total of 30 impressions of stainless steel die were made, out of which 15 impressions were made with conventional alginate and 15 were made with self-disinfecting alginate and poured using Type III dental stone. Thirty stone specimens were subjected for hardness testing. Data were analyzed using independent samples t-test to compare the mean surface hardness. Difference in surface hardness was statistically insignificant (p > 0.05). Surface hardness of gypsum casts poured using impressions made from self-disinfecting alginate and conventional alginates were comparable. Self-disinfecting alginates may be employed in clinical practice as safe and effective materials to overcome the infection control issues without compromising on the properties of the material.

Structural evolution of gypsum under high pressure: single-crystal X-ray experiments revisited

NASA Astrophysics Data System (ADS)

Li, Tsung-Lung; Lee, Pei-Lun

2018-05-01

The structures of gypsum at pressures up to approximately 4 GPa are studied with density functional theory (DFT) and thoroughly compared with single-crystal X-ray diffraction experiments reported in the literature [Comodi et al. in (Am Miner 93:1530-1537, 2008)]. It is found that the exchange-correlation density functional revPBE (revised Perdew-Burke-Ernzerhof) in conjunction with a nonlocal van der Waals (vdW) correction is capable of modeling the lattice constants, axial compressibility, and bulk modulus with good accuracy, suggesting that the inclusion of the vdW functional is crucially important for understanding the structure of hydrous minerals. To gain further physical insights, the geometric parameters associated with the constituting components of gypsum (water molecules, SO4 tetrahedra, and CaO8 polyhedra) are analyzed and compared with the experimental values. DFT simulations show that, under pressure, the polyhedral layers remain as nearly planar sheets of interconnecting SO4 tetrahedra and CaO8 polyhedra without further crinkling. DFT analysis on the layer compressibility along the major crystal axis reveals that, in contrast to experimental reports, the hydrous interlayer is less compressible than the polyhedral layer. Squeezed by the lateral pressure, the water molecules in the hydrous interlayer become better affixed along the major axis, making the interlayer harder to compress along this axis.

Research on Crack Formation in Gypsum Partitions with Doorway by Means of FEM and Fracture Mechanics

NASA Astrophysics Data System (ADS)

Kania, Tomasz; Stawiski, Bohdan

2017-10-01

Cracking damage in non-loadbearing internal partition walls is a serious problem that frequently occurs in new buildings within the short term after putting them into service or even before completion of construction. Damage in partition walls is sometimes so great that they cannot be accepted by their occupiers. This problem was illustrated by the example of damage in a gypsum partition wall with doorway attributed to deflection of the slabs beneath and above it. In searching for the deflection which causes damage in masonry walls, fracture mechanics applied to the Finite Element Method (FEM) have been used. For a description of gypsum behaviour, the smeared cracking material model has been selected, where stresses are transferred across the narrowly opened crack until its width reaches the ultimate value. Cracks in the Finite Element models overlapped the real damage observed in the buildings. In order to avoid cracks under the deflection of large floor slabs, the model of a wall with reinforcement in the doorstep zone and a 40 mm thick elastic junction between the partition and ceiling has been analysed.

7 CFR 1250.304 - Egg Board or Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Egg Board or Board. 1250.304 Section 1250.304... AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE EGG RESEARCH AND PROMOTION Egg Research and Promotion Order Definitions § 1250.304 Egg Board or Board. Egg Board or Board or other...

7 CFR 1250.304 - Egg Board or Board.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 10 2011-01-01 2011-01-01 false Egg Board or Board. 1250.304 Section 1250.304... AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE EGG RESEARCH AND PROMOTION Egg Research and Promotion Order Definitions § 1250.304 Egg Board or Board. Egg Board or Board or other...

Boarding Schools and Capital Benefits: Implications for Urban School Reform

ERIC Educational Resources Information Center

Bass, Lisa R.

2014-01-01

The author discusses the boarding school model as a schooling alternative to improve life chances for disadvantaged youth, particularly African American youth, by positively meeting their social and educational needs. Bourdieu, Coleman, and other social scientists purported that these needs can be better met by exposing students to social and…

Populations of some molds in water-damaged homes may differ if the home was constructed with gypsum drywall compared to plaster.

PubMed

Vesper, Stephen; Wymer, Larry; Cox, David; Dewalt, Gary

2016-08-15

Starting in the 1940s, gypsum drywall began replacing plaster and lathe in the U.S. home construction industry. Our goal was to evaluate whether some mold populations differ in water- damaged homes primarily constructed with gypsum drywall compared to plaster. The dust samples from the 2006 Department of Housing and Urban Development's (HUD) American Health Homes Survey (AHHS) were the subject of this analysis. The concentrations of the 36 Environmental Relative Moldiness Index (ERMI) molds were compared in homes of different ages. The homes (n=301) were built between 1878 and 2005. Homes with ERMI values >5 (n=126) were defined as water-damaged. Homes with ERMI values >5 were divided in the years 1976 to 1977 into two groups, i.e., older (n=61) and newer (n=65). Newer water-damaged homes had significantly (p=0.002) higher mean ERMI values than older water-damaged homes, 11.18 and 8.86, respectively. The Group 1 molds Aspergillus flavus, Ammophilus fumigatus, Aspergillus ochraceus, Cladosporium sphaerospermum and Trichoderma viride were found in significantly higher concentrations in newer compared to older high-ERMI homes. Some mold populations in water-damaged homes may have changed after the introduction of gypsum drywall. Published by Elsevier B.V.

Determination of trace elements in dolomite and gypsum by atomic absorption spectrometry: overcoming the matrix interference by flotation separation

NASA Astrophysics Data System (ADS)

Stafilov, Trajče; Zendelovska, Dragica; Pavlovska, Gorica; Čundeva, Katarina

2002-05-01

The interferences of Ca and Mg as matrix elements in dolomite and gypsum on Ag, Cd, Cr, Mn, Tl and Zn absorbances during their electrothermal atomic absorption spectrometric (ETAAS) determination are investigated. The results reveal that Ca and Mg do not interfere on Zn and Mn, tend to decrease absorbances of Ag, Cd and Cr, while Tl suffers the most significant influence. A flotation separation method is proposed to eliminate matrix interferences. Hydrated iron(III) oxide, Fe 2O 3· xH 2O, and iron(III) hexamethylenedithiocarbamate, Fe(HMDTC) 3, are applied as flotation collectors. The influence of hydrophobic dithiocarbamate anion, HMDTC, on flotation recoveries of each analyte is studied. The most suitable concentrations of dolomite and gypsum solutions for flotation are determined. To avoid flotation suppression due to the reaction of Ca 2+ and Mg 2+ with surfactant ions, a fit foaming agent was selected. The elements present in dolomite and gypsum as traces have been analyzed by ETAAS. Their ETAAS limits of detection following flotation are found to be 0.021 μg·g -1 for Ag, 0.019 μg·g -1 for Cd, 0.014 μg·g -1 for Cr and 0.11 μg·g -1 for Tl. The determination of Mn and Zn can be performed by flame AAS (FAAS). The limit of detection for Mn is 1.5 μg·g -1, while for Zn 0.8 μg·g -1.

Contribution study to the thermal insulation of the builders in the desert regions of exploiting gypsum fiber reinforced palm

NASA Astrophysics Data System (ADS)

Hafsi, Fouad; Kriker, Abdelouahed; Abani, Said

2017-02-01

Algerian Desert areas were characterized by very hot climate in summer and very cold in winter. The most widely used building material in these areas are concrete, mortar cement, which has a bad thermal insulation, causing a significant increase in cooling and heating costs; in order to avoid this problem it become a must to replace these materials with a good thermal isolation material and lower production cost. This work is part of the evaluation of local materials by improving their performance in the field of thermal insulation, which is considered a first step in the development of new local materials to be used in the construction field, the material used in this study is the gypsum reinforced with date palm fiber. In fact, Algeria has extraordinary resources in natural fibers (from Palm, Abaca, Hemp…) but without any large valorization in building materials. The aim of this work is then to characterization of those date palm fibers in new building materials approved for use in the construction of buildings in the desert areas. The date palm fibers were added to samples of the gypsum material in the form of cutting layers at different volume fraction, so as to determine the extent of their impact in the improvement of the thermal performance. The results were very satisfactory, reaching improvement rate of 16% for samples gypsum reinforced with single cut fiber form, and 32% of the samples reinforced with fiber in the form of layers.

Modern Geodetic Measurement Techniques in Gravimetric Studies on the Example of Gypsum Karst in the Siesławice Region

NASA Astrophysics Data System (ADS)

Porzucek, Sławomir; Łój, Monika; Matwij, Karolina; Matwij, Wojciech

2018-03-01

In the region of Siesławice (near Busko-Zdrój, Poland) there are unique phenomena of gypsum karst. Atmospheric factors caused numerous gypsum outcrops, canals and underground voids. The article presents the possibility of using non-invasive gravimetric surveys supplemented with geodetic measurements to illustrate karst changes occurring around the void. The use of modern geodetic measurement techniques including terrestrial and airborne laser scanning enables to generate a digital terrain model and a three-dimensional model of voids. Gravimetric field studies allowed to map the anomalies of the gravitational field of the near-surface zone. Geodetic measurement results have made it possible to accurately determine the terrain correction that supplemented the gravimetric anomaly information. Geophysical interpretation indicate the presence of weathered rocks in the near surface zone and fractures and loosened zones located surround the karst cave.

Potential adherence of flue gas desulfurization gypsum to forage as a consideration for excessive ingestion by ruminants

USDA-ARS?s Scientific Manuscript database

Gypsum (calcium sulfate dihydrate, CaSO4·2H2O) has long been used to improve soils and crop production, and its use has recently been encouraged by the USDA-NRCS for soil conservation through a new Conservation Practice Standard: Code 333. However, there is concern regarding adverse effects of exce...

Contaminations of inner surface of magnesium fluoride windows in the `Expose-R' experiment on the International Space Station

NASA Astrophysics Data System (ADS)

Skurat, V. E.

2017-10-01

A series of experiments was carried out previously on board of the International Space Station in `EXPOSE-R', a multi-user expose facility, provided by European Space Agency attached to the external surface of the Russian Segment. In one experiment, spores of microorganisms and species of higher plant seeds, in heat-sealed polymer bags were irradiated by solar radiation passed through MgF2 windows in a high space vacuum. After sample exposure, it was found that in many cases the inner surfaces of windows were contaminated. Analysis of the contamination revealed the presence of chemical groups CH2, CH3, NH, OH, C═O, Si-CH3 (Demets et al. in 2015). Their presence in deposits was explained by photofixation of gaseous precursors - some of the vapours of glues and additives in polymeric materials in the core facility of `Expose-R'. Carbon-, oxygen- and silicon-containing groups may be deposited from outer intrinsic atmosphere. This atmosphere is connected with sample compartments and core facility. However, the presence of NH groups on inner surfaces of windows was not expected. This paper shows that the process responsible for carbon-, nitrogen- and oxygen-containing group formation can be a photopolymerization of caprolactam, which is released from the outer Nylon 6 layer of polymer bags under Solar vacuum ultraviolet radiation.

Rehabilitation of gypsum-mined lands in the Indian desert

USGS Publications Warehouse

Sharma, K.D.; Kumar, S.; Gough, L.P.

2001-01-01

The economic importance of mining in the Indian Desert is second only to agriculture. Land disturbed by mining, however, has only recently been the focus of rehabilitation efforts. This research assesses the success of rehabilitation plans used to revegetate gypsum mine spoils within the environmental constraints of the north-west Indian hot-desert ecosystem. The rehabilitation plan first examined both mined and unmined areas and established assessments of existing vegetative cover and the quality of native soils and mine spoils. Tests were made on the effect of the use, and conservation, of available water through rainwater harvesting, amendment application (for physical and chemical spoil modification), plant establishment protocols, and the selection of appropriate germ plasm. Our results show that the resulting vegetative cover is capable of perpetuating itself under natural conditions while concurrently meeting the needs of farmers. Although the mine spoils are deficient in organic matter and phosphorus, they possess adequate amounts of all other nutrients. Total boron concentrations (>5.0 mg kg-1) in both the topsail and mine spoil indicate potentially phytotoxic conditions. Electrical conductance of mine spoil is 6-10 times higher than for topsail with a near-neutral pH. Populations of spoil fungi, Azotobactor, and nitrifying bacteria are low. The soil moisture storage in rainwater harvesting plots increased by 8% over the control and 48% over the unmined area. As a result of rehabilitation efforts, mine spoils show a steady buildup in organic carbon, and P and K due to the decomposition of farmyard manure and the contribution of nitrogen fixation by the established leguminous plant species. The rehabilitation protocol used at the site appears to have been successful. Following revegetation of the area with a mixture of trees, shrubs, and grasses, native implanted species have become established. Species diversity, measured in terms of species richness

Survival of Spores of Trichoderma longibrachiatum in Space: data from the Space Experiment SPORES on EXPOSE-R

NASA Astrophysics Data System (ADS)

Neuberger, Katja; Lux-Endrich, Astrid; Panitz, Corinna

2015-01-01

In the space experiment `Spores in artificial meteorites' (SPORES), spores of the fungus Trichoderma longibrachiatum were exposed to low-Earth orbit for nearly 2 years on board the EXPOSE-R facility outside of the International Space Station. The environmental conditions tested in space were: space vacuum at 10-7-10-4 Pa or argon atmosphere at 105 Pa as inert gas atmosphere, solar extraterrestrial ultraviolet (UV) radiation at λ > 110 nm or λ > 200 nm with fluences up to 5.8 × 108 J m-2, cosmic radiation of a total dose range from 225 to 320 mGy, and temperature fluctuations from -25 to +50°C, applied isolated or in combination. Comparable control experiments were performed on ground. After retrieval, viability of spores was analysed by two methods: (i) ethidium bromide staining and (ii) test of germination capability. About 30% of the spores in vacuum survived the space travel, if shielded against insolation. However, in most cases no significant decrease was observed for spores exposed in addition to the full spectrum of solar UV irradiation. As the spores were exposed in clusters, the outer layers of spores may have shielded the inner part. The results give some information about the likelihood of lithopanspermia, the natural transfer of micro-organisms between planets. In addition to the parameters of outer space, sojourn time in space seems to be one of the limiting parameters.

Arsenic uptake by gypsum and calcite: Modelling and probing by neutron and X-ray scattering

NASA Astrophysics Data System (ADS)

Fernández-Martínez, A.; Román-Ross, G.; Cuello, G. J.; Turrillas, X.; Charlet, L.; Johnson, M. R.; Bardelli, F.

2006-11-01

Uptaking of contaminants by solid phases is relevant to many issues in environmental science as this process can remove them from solutions and retard their transport into the hydrosphere. Here we report on two structural studies performed on As-doped gypsum (CaSO 4 2H 2O) and calcite (CaCO 3), using neutron (D20-ILL) and X-ray (ID11-ESRF) diffraction data and EXAFS (BM8-ESRF). The aim of this study is to determine whether As gets into the bulk of gypsum and calcite structures or is simply adsorbed on the surface. Different mechanisms of substitution are used as hypotheses. The combined Rietveld analysis of neutron and X-ray diffraction data shows an expansion of the unit cell volume proportional to the As concentration within the samples. DFT-based simulations confirm the increase of the unit cell volume proportional to the amount of carbonate or sulphate groups substituted. Interpolation of the experimental Rietveld data allows us to distinguish As substituted within the structure from that adsorbed on the surface of both minerals. Results obtained by EXAFS analysis from calcite samples show good agreement with the hypothesis of replacement of As into the C crystallographic site.

Study on Shear Performance of Cold-formed Steel Composite Wall with New Type of stud

NASA Astrophysics Data System (ADS)

Wang, Chungang; Yue, Sizhe; Liu, Hong; Zhang, Zhuangnan

2018-03-01

The shear resistance of single oriented-strand board wall and single gypsum board wall can be improved in different degrees by increasing strength of steel. The experimental data of literatures were used, and the test specimens had been simulated and validated by ABAQUS finite element analysis. According to the research, it showed that the compressive bearing capacity of the new stud composite wall was much better than the common stud composite wall, so the establishment and research of all models had been based on the new section stud. The analysis results show that when using new type of stud the shear resistance of the single oriented-strand board wall can be improved efficiently by increasing strength of steel, but the shear resistance of the single gypsum wall can be increased little.

Impact experiments of porous gypsum-glass bead mixtures simulating parent bodies of ordinary chondrites: Implications for re-accumulation processes related to rubble-pile formation

NASA Astrophysics Data System (ADS)

Yasui, Minami; Arakawa, Masahiko

2011-08-01

Laboratory impact experiments were conducted for gypsum-glass bead targets simulating the parent bodies of ordinary chondrites. The effects of the chondrules included in the parent bodies on impact disruption were experimentally investigated in order to determine the impact conditions for the formation of rubble-pile bodies after catastrophic disruption. The targets included glass beads with a diameter ranging from 100 μm to 3 mm and the volume fraction was 0.6, similar to that of ordinary chondrites, which is about 0.65-0.75. Nylon projectiles with diameters of 10 mm and 2 mm were impacted at 60-180 m s -1 by a single-stage gas gun and at 4 km s -1 by a two-stage light gas gun, respectively. The impact strength of the gypsum-glass bead target was found to range from 56 to 116 J kg -1 depending on the glass bead size, and was several times smaller than that of the porous gypsum target, 446 J kg -1 in low-velocity collisions. The impact strengths of the 100 μm bead target and the porous gypsum target strongly depended on the impact velocity: those obtained in high-velocity collisions were several times greater than those obtained in low-velocity collisions. The velocities of fragments ejected from two corners on the impact surface of the target, measured in the center of the mass system, were slightly dependent on the target materials, irrespective of impact velocity. These results suggest that chondrule-including planetesimals (CiPs) can reconstruct rubble-pile bodies in catastrophic disruptions at the size of the planetesimal smaller than that of planetesimals without chondrules.

Metals in soil and runoff from a piedmont hayfield amended with broiler litter and flue gas desulfurization gypsum

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization gypsum (FGDG) from coal-fired power plants is available for agricultural use in many US regions. Broiler litter (BL) provides plant available N, P, and K but may be a source of unwanted arsenic (As), copper (Cu), and zinc (Zn). FGDG provides Ca and S and can reduce runoff lo...

Land subsidence and caprock dolines caused by subsurface gypsum dissolution and the effect of subsidence on the fluvial system in the Upper Tigris Basin (between Bismil Batman, Turkey)

NASA Astrophysics Data System (ADS)

Doğan, Uğur

2005-11-01

Karstification-based land subsidence was found in the Upper Tigris Basin with dimensions not seen anywhere else in Turkey. The area of land subsidence, where there are secondary and tertiary subsidence developments, reaches 140 km 2. Subsidence depth ranges between 40 and 70 m. The subsidence was formed as a result of subsurface gypsum dissolution in Lower Miocene formation. Although there are limestones together with gypsum and Eocene limestone below them in the area, a subsidence with such a large area is indicative of karstification in the gypsum. The stratigraphical cross-sections taken from the wells and the water analyses also verify this fact. The Lower Miocene gypsum, which shows confined aquifer features, was completely dissolved by the aggressive waters injected from the top and discharged through by Zellek Fault. This resulted in the development of subsidence and formation of caprock dolines on loosely textured Upper Miocene-Pliocene cover formations. The Tigris River runs through the subsidence area between Batman and Bismil. There are four terrace levels as T1 (40 m), T2 (30 m), T3 (10 m) and T4 (4-5 m) in the Tigris River valley. It was also found that there were some movements of the levels of the terraces in the valley by subsidence. The subsidence developed gradually throughout the Quaternary; however no terrace was formed purely because of subsidence.

Comparison of cosmic rays radiation detectors on-board commercial jet aircraft.

PubMed

Kubančák, Ján; Ambrožová, Iva; Brabcová, Kateřina Pachnerová; Jakůbek, Jan; Kyselová, Dagmar; Ploc, Ondřej; Bemš, Július; Štěpán, Václav; Uchihori, Yukio

2015-06-01

Aircrew members and passengers are exposed to increased rates of cosmic radiation on-board commercial jet aircraft. The annual effective doses of crew members often exceed limits for public, thus it is recommended to monitor them. In general, the doses are estimated via various computer codes and in some countries also verified by measurements. This paper describes a comparison of three cosmic rays detectors, namely of the (a) HAWK Tissue Equivalent Proportional Counter; (b) Liulin semiconductor energy deposit spectrometer and (c) TIMEPIX silicon semiconductor pixel detector, exposed to radiation fields on-board commercial Czech Airlines company jet aircraft. Measurements were performed during passenger flights from Prague to Madrid, Oslo, Tbilisi, Yekaterinburg and Almaty, and back in July and August 2011. For all flights, energy deposit spectra and absorbed doses are presented. Measured absorbed dose and dose equivalent are compared with the EPCARD code calculations. Finally, the advantages and disadvantages of all detectors are discussed. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The effect of gypsum products and separating materials on the typography of denture base materials.

PubMed

Firtell, D N; Walsh, J F; Elahi, J M

1980-09-01

The typography of polymethyl methacrylate processed against various gypsum products coated with various separating materials was studied under an SEM. Tinfoil and two commercial tin foil substitutes were used as separating material during processing, and the surfaces of the resulting acrylic resin forms were studied for topographical differences. Tinfoil and alpha 2 hemihydrates produced the smoothest surfaces. As a practical solution, a good quality tinfoil substitute and alpha 1 hemihydrate could be used when processing polymethyl methacrylate resin.

Evaluation of Different Disinfactants on Dimensional Accuracy and Surface Quality of Type IV Gypsum Casts Retrieved from Elastomeric Impression Materials.

PubMed

Pal, P K; Kamble, Suresh S; Chaurasia, Ranjitkumar Rampratap; Chaurasia, Vishwajit Rampratap; Tiwari, Samarth; Bansal, Deepak

2014-06-01

The present study was done to evaluate the dimensional stability and surface quality of Type IV gypsum casts retrieved from disinfected elastomeric impression materials. In an in vitro study contaminated impression material with known bacterial species was disinfected with disinfectants followed by culturing the swab sample to assess reduction in level of bacterial colony. Changes in surface detail reproduction of impression were assessed fallowing disinfection. All the three disinfectants used in the study produced a 100% reduction in colony forming units of the test organisms. All the three disinfectants produced complete disinfection, and didn't cause any deterioration in surface detail reproduction. How to cite the article: Pal PK, Kamble SS, Chaurasia RR, Chaurasia VR, Tiwari S, Bansal D. Evaluation of dimensional stability and surface quality of type IV gypsum casts retrieved from disinfected elastomeric impression materials. J Int Oral Health 2014;6(3):77-81.

Influence of flue gas desulfurization gypsum on reducing soluble phosphorus in successive runoff events from a coastal plain bermudagrass pasture

USDA-ARS?s Scientific Manuscript database

Controlling the potential threat that pasture systems which have been intensively fertilized with poultry litter (PL) pose to accelerate eutrophication of surface waters has become a major issue in the southeastern U.S. Gypsum has been identified as a promising management tool for ameliorating the ...

Simplified Methods for Improving the Blast Resistance of Cold-Formed Steel Walls

DTIC Science & Technology

2011-01-01

sheathing products such as oriented strand board ( OSB ) offer a level of blast resistance that may be effective in mitigating lower-level blast...considered in order to keep designs to a minimum cost. Standard sheathing materials such as OSB , gypsum and plywood— as well as specially selected sheathing...commercially available clip connectors. Sheathing materials such as gypsum and OSB are brittle and have significantly lower capacity than sheet steel

Estimating mineral abundances of clay and gypsum mixtures using radiative transfer models applied to visible-near infrared reflectance spectra

NASA Astrophysics Data System (ADS)

Robertson, K. M.; Milliken, R. E.; Li, S.

2016-10-01

Quantitative mineral abundances of lab derived clay-gypsum mixtures were estimated using a revised Hapke VIS-NIR and Shkuratov radiative transfer model. Montmorillonite-gypsum mixtures were used to test the effectiveness of the model in distinguishing between subtle differences in minor absorption features that are diagnostic of mineralogy in the presence of strong H2O absorptions that are not always diagnostic of distinct phases or mineral abundance. The optical constants (k-values) for both endmembers were determined from bi-directional reflectance spectra measured in RELAB as well as on an ASD FieldSpec3 in a controlled laboratory setting. Multiple size fractions were measured in order to derive a single k-value from optimization of the optical path length in the radiative transfer models. It is shown that with careful experimental conditions, optical constants can be accurately determined from powdered samples using a field spectrometer, consistent with previous studies. Variability in the montmorillonite hydration level increased the uncertainties in the derived k-values, but estimated modal abundances for the mixtures were still within 5% of the measured values. Results suggest that the Hapke model works well in distinguishing between hydrated phases that have overlapping H2O absorptions and it is able to detect gypsum and montmorillonite in these simple mixtures where they are present at levels of ∼10%. Care must be taken however to derive k-values from a sample with appropriate H2O content relative to the modeled spectra. These initial results are promising for the potential quantitative analysis of orbital remote sensing data of hydrated minerals, including more complex clay and sulfate assemblages such as mudstones examined by the Curiosity rover in Gale crater.

Resistance of insecticide-treated foam board insulation against the eastern subterranean termite and the Formosan subterranean termite (Isoptera: Rhinotermitidae).

PubMed

Su, Nan-Yao; Ban, Paul; Scheffrahn, Rudolf H

2003-10-01

Three foam board types, one untreated control, one containing 2,000 ppm disodium octaborate tetrahydrate (DOT), and one containing 1,000 ppm deltamethrin, were exposed to field populations of the eastern subterranean termite, Reticulitermes flavipes (Kollar), and the Formosan subterranean termite, Coptotermes formosanus Shiraki. There was no significant difference in termite damage between foam boards treated with 2,000 ppm DOT and the untreated control. Form boards containing 1,000 ppm deltamethrin were not damaged by R. flavipes, whereas only minor damage occurred after exposure to C. formosanus.

Triple oxygen and hydrogen isotopes of gypsum hydration water for quantitative paleo-humidity reconstruction

NASA Astrophysics Data System (ADS)

Gázquez, Fernando; Morellón, Mario; Bauska, Thomas; Herwartz, Daniel; Surma, Jakub; Moreno, Ana; Staubwasser, Michael; Valero-Garcés, Blas; Delgado-Huertas, Antonio; Hodell, David A.

2018-01-01

Atmospheric relative humidity is an important parameter affecting vegetation yet paleo-humidity proxies are scarce and difficult to calibrate. Here we use triple oxygen (δ17O and δ18O) and hydrogen (δD) isotopes of structurally-bound gypsum hydration water (GHW) extracted from lacustrine gypsum to quantify past changes in atmospheric relative humidity. An evaporation isotope-mass-balance model is used together with Monte Carlo simulations to determine the range of climatological conditions that simultaneously satisfy the stable isotope results of GHW, and with statistically robust estimates of uncertainty. We apply this method to reconstruct the isotopic composition of paleo-waters of Lake Estanya (NE Spain) and changes in normalized atmospheric relative humidity (RHn) over the last glacial termination and Holocene (from ∼15 to 0.6 cal. kyrs BP). The isotopic record indicates the driest conditions occurred during the Younger Dryas (YD; ∼12-13 cal. kyrs BP). We estimate a RHn of ∼40-45% during the YD, which is ∼30-35% lower than today. Because of the southward displacement of the Polar Front to ∼42°N, it was both windier and drier during the YD than the Bølling-Allerød period and Holocene. Mean atmospheric moisture gradually increased from the Preboreal to Early Holocene (∼11 to 8 cal. kyrs BP, 50-60%), reaching 70-75% RHn from ∼7.5 cal. kyrs BP until present-day. We demonstrate that combining hydrogen and triple oxygen isotopes in GHW provides a powerful tool for quantitative estimates of past changes in relative humidity.

Runaway chemical reaction exposes community to highly toxic chemicals.

PubMed

Kaszniak, Mark; Vorderbrueggen, John

2008-11-15

The U.S. Chemical Safety and Hazard Investigation Board (CSB) conducted a comprehensive investigation of a runaway chemical reaction at MFG Chemical (MFG) in Dalton, Georgia on April 12, 2004 that resulted in the uncontrolled release of a large quantity of highly toxic and flammable allyl alcohol and allyl chloride into the community. Five people were hospitalized and 154 people required decontamination and treatment for exposure to the chemicals. This included police officers attempting to evacuate the community and ambulance personnel who responded to 911 calls from residents exposed to the chemicals. This paper presents the findings of the CSB report (U.S. Chemical Safety and Hazard Investigation Board (CSB), Investigation Report: Toxic Chemical Vapor Cloud Release, Report No. 2004-09-I-GA, Washington DC, April 2006) including a discussion on tolling practices; scale-up of batch reaction processes; Process Safety Management (PSM) and Risk Management Plan (RMP) implementation; emergency planning by the company, county and the city; and emergency response and mitigation actions taken during the incident. The reactive chemical testing and atmospheric dispersion modeling conducted by CSB after the incident and recommendations adopted by the Board are also discussed.

Three annual flue gas desulfurization gypsum applications on macronutrient and micronutrient losses in runoff from bermudagrass fertilized with poultry litter

USDA-ARS?s Scientific Manuscript database

Considerable amounts of flue gas desulfurization (FGD) gypsum are being produced as a by-product of generating electricity. As a result, beneficial reuse of this by-product is being sought to reduce landfilling and its associated cost. The use of this byproduct as a low-cost soil amendment for suppl...

Microbial volatile organic compound emissions from Stachybotrys chartarum growing on gypsum wallboard and ceiling tile.

PubMed

Betancourt, Doris A; Krebs, Ken; Moore, Scott A; Martin, Shayna M

2013-12-05

Stachybotrys chartarum is a filamentous mold frequently identified among the mycobiota of water-damaged building materials. Growth of S. chartarum on suitable substrates and under favorable environmental conditions leads to the production of secondary metabolites such as mycotoxins and microbial volatile organic compounds (MVOCs). The aim of this study was to characterize MVOC emission profiles of seven toxigenic strains of S. chartarum, isolated from water-damaged buildings, in order to identify unique MVOCs generated during growth on gypsum wallboard and ceiling tile coupons. Inoculated coupons were incubated and monitored for emissions and growth using a closed glass environmental growth chamber maintained at a constant room temperature. Gas samples were collected from the headspace for three to four weeks using Tenax TA tubes. Most of the MVOCs identified were alcohols, ketones, ethers and esters. The data showed that anisole (methoxybenzene) was emitted from all of the S. chartarum strains tested on both types of substrates. Maximum anisole concentration was detected after seven days of incubation. MVOCs are suitable markers for fungal identification because they easily diffuse through weak barriers like wallpaper, and could be used for early detection of mold growth in hidden cavities. This study identifies the production of anisole by seven toxigenic strains of Stachybotrys chartarum within a period of one week of growth on gypsum wallboard and ceiling tiles. These data could provide useful information for the future construction of a robust MVOC library for the early detection of this mold.

Dimensional stability of flakeboards as affected by board specific gravity and flake alignment

Treesearch

Robert L. Geimer

1982-01-01

The objective was to determine the relationship between the variables specific gravity (SG) and flake alignment and the dimensional stability properties of flakeboard. Boards manufactured without a density gradient were exposed to various levels of relative humidity and a vacuum-pressure soak (VPS) treatment. Changes in moisture content (MC), thickness swelling, and...

Board-to-board optical interconnection using novel optical plug and slot

NASA Astrophysics Data System (ADS)

Cho, In K.; Yoon, Keun Byoung; Ahn, Seong H.; Kim, Jin Tae; Lee, Woo Jin; Shin, Kyoung Up; Heo, Young Un; Park, Hyo Hoon

2004-10-01

A novel optical PCB with transmitter/receiver system boards and optical bakcplane was prepared, which is board-to-board interconnection by optical plug and slot. We report an 8Gb/s PRBS NRZ data transmission between transmitter system board and optical backplane embedded multimode polymeric waveguide arrays. The basic concept of ETRI's optical PCB is as follows; 1) Metal optical bench is integrated with optoelectronic devices, driver and receiver circuits, polymeric waveguide and access line PCB module. 2) Multimode polymeric waveguide inside an optical backplane, which is embedded into PCB. 3) Optical slot and plug for high-density(channel pitch : 500um) board-to-board interconnection. The polymeric waveguide technology can be used for transmission of data on transmitter/ receiver system boards and for backplane interconnections. The main components are low-loss tapered polymeric waveguides and a novel optical plug and slot for board-to-board interconnections, respectively. The optical PCB is characteristic of low coupling loss, easy insertion/extraction of the boards and, especially, reliable optical coupling unaffected from external environment after board insertion.

FIRE TEST AND HEAT ANALYSIS FOR STEEL-CONCRETE COMPOSITE MEMBER WITH FIREPROOF BOARD

NASA Astrophysics Data System (ADS)

Nakai, Akihiro; Kiyomiya, Osamu

Composite members made of steel and concrete have been widely adopted for undersea tunnels. Since steel plates are exposed to the internal side of the tunnel, vehicle fire countermeasures are required. First, the RABT heating test for the composite members without the fireproof board was executed, and the damage and the deterioration of the internal concrete were examined. Next, the transmission mechanism of heat in the air layer between the fireproof board and the steel was aloso examined by the element test to mesure the heat flow by the radiation, convection, and the conduction. Furthermore, the RABT heating test with fireproof board was executed, and the internal temperature was measured and the effect of the air layer was confirmed. Finally, validity of the proposed analytical model was confirmed by comparing the heat analysis results with the heat tests results.

Cellulose nanofiber board.

PubMed

Yousefi, Hossein; Azad, Sona; Mashkour, Mahdi; Khazaeian, Abolghasem

2018-05-01

A cellulose nanofiber board (CNF-board) with a nominal thickness of 3 mm was fabricated without adhesive or additive. To provide comparison, a cellulose fiber board (CF-board) was also fabricated. A novel cold pre-press apparatus was made to dewater highly absorbent CNF gel prior to drying. A mild drying condition in the vacuum oven at 70 °C and 0.005 MPa was enough to provide the CNF-board with a density of 1.3 g/cm 3 thanks to its self-densification capability. Unlike the CF-board, the fabricated CNF-board had a high water-activated dimensional recovery ratio (averagely 96%) during the five cyclic wetting-drying process. The flexural and tensile strengths of CNF-board obtained were 162 MPa and 85 MPa, respectively. The corresponding values for CF-board were 28 MPa and 11 MPa, respectively. The specific flexural and tensile strengths of CNF-board obtained were higher than those of CF-board as well as some other traditional wood-based composites, polymers and structural ASTM A36 steel. Copyright © 2018 Elsevier Ltd. All rights reserved.

BIOMEX on EXPOSE-R2: First results on the preservation of Raman biosignatures after space exposure

NASA Astrophysics Data System (ADS)

Baqué, Mickael; Böttger, Ute; Leya, Thomas; de Vera, Jean-Pierre Paul

2017-04-01

After a 15-month exposure on-board the EXPOSE-R2 space platform, situated on the outside of the International Space Station, four astrobiology experiments successfully came back to Earth in March and June 2016. Among them, the BIOMEX (BIOlogy and Mars EXperiment) experiment aims at investigating the endurance of extremophiles and stability of biomolecules under space and Mars-like conditions in the presence of Martian mineral analogues (de Vera et al., 2012). The preservation and evolution of Raman biosignatures under such conditions is of particular interest for guiding future search-for-life missions to Mars (and other planetary objects) carrying Raman spectrometers (such as the Raman Laser Spectrometer instrument on board the future ExoMars rover). The photoprotective carotenoid pigments (present either in photosynthetic organisms such as plants, algae, cyanobacteria and in some bacteria and archaea) have been classified as high priority targets for biomolecule detection on Mars and therefore used as biosignature models due to their stability and easy identification by Raman spectroscopy (Böttger et al., 2012). We report here on the first results from the analysis of two carotenoids containing organisms: the cyanobacterium Nostoc sp. (strain CCCryo 231-06; = UTEX EE21 and CCMEE 391) isolated from Antarctica and the green alga cf. Sphaerocystis sp. (strain CCCryo 101-99) isolated from Spitsbergen. Desiccated cells of these organisms were exposed to space and simulated Mars-like conditions in space in the presence of two Martian mineral analogues (phyllosilicatic and sulfatic Mars regolith simulants) and a Lunar regolith analogue and analyzed with a 532nm Raman microscope at 1mW laser power. Carotenoids in both organisms were surprisingly still detectable at relatively high levels after being exposed for 15 months in Low Earth Orbit to UV, cosmic rays, vacuum (or Mars-like atmosphere) and temperatures stresses regardless of the mineral matrix used. Further

Hydrated Minerals in Circumpolar Terrains: Geographic Distribution, Mineralogical Composition and Possible Origins

NASA Astrophysics Data System (ADS)

Langevin, Y.; Poulet, F.; Fishbaugh, K. E.; Roach, L.; Vincendon, M.; Gondet, B.; Bibring, J.; Murchie, S.

2007-12-01

The nearly global mapping provided at a scale of a few km by the OMEGA Vis/NIR imaging spectrometer on board Mars Express revealed that hydrated minerals on Mars are mostly observed in ancient terrains (Bibring et al., 2005). These discoveries led to the conclusion that surface water on Mars was mainly present early in the history of the planet, and that Mars has remained cold and dry during the last 3 billion years (Bibring et al., 2006). The observation by OMEGA of a very strong calcium sulfate signature (most likely dominated by gypsum) within the boundaries of the Olympia Planitia Dune field (Langevin et al., 2005) is a major puzzle as this geological feature is at most a few 100 m.y. old. An independent analysis of the OMEGA data (Horgan et al. 2007) confirmed the results of Langevin et al. (2005), in particular the identification of gypsum as the dominant mineralogical hydrated species in the dune field. The extended region richest in gypsum (~ 60 km x 200 km) remained unresolved at a resolution of 1 km/pixel (Langevin et al., 2006). With its 20 m resolution, CRISM, the Vis/NIR imaging spectrometer on board MRO, secured the relationship between the gypsum signature and the dune field as well as its absence over the "basal unit" (only a few pixels wide in OMEGA data) which is exposed between the dune field and the ice (Roach et al., 2007). CRISM showed that the gypsum signatures were highest over dune crests and weakest over exposed bedrock. Mineralogical modeling of the CRISM and OMEGA spectra shows that Gypsum represents at least 60% of the dune material in the eastern part of the Olympia field and decreases towards the western part. This lower limit has been raised since then by accounting for aerosol contributions which reduce the strength of absorption bands. The low albedo (< 20%) requires significant intimate and/or intra- mixture of dark material. The low thermal inertia (Herkenhoff and Vasavada, 1999) is difficult to reconcile with morphologic

Late Glacial temperature and precipitation changes in the lowland Neotropics by tandem measurement of δ 18O in biogenic carbonate and gypsum hydration water

NASA Astrophysics Data System (ADS)

Hodell, David A.; Turchyn, Alexandra V.; Wiseman, Camilla J.; Escobar, Jaime; Curtis, Jason H.; Brenner, Mark; Gilli, Adrian; Mueller, Andreas D.; Anselmetti, Flavio; Ariztegui, Daniel; Brown, Erik T.

2012-01-01

We applied a new method to reconstruct paleotemperature in the tropics during the last deglaciation by measuring oxygen isotopes of co-occurring gypsum hydration water and biogenic carbonate in sediment cores from two lakes on the Yucatan Peninsula. Oxygen and hydrogen isotope values of interstitial and gypsum hydration water indicate that the crystallization water preserves the isotopic signal of the lake water, and has not undergone post-depositional isotopic exchange with sediment pore water. The estimated lake water δ18O is combined with carbonate δ18O to calculate paleotemperature. Three paired measurements of 1200-yr-old gypsum and gastropod aragonite from Lake Chichancanab, Mexico, yielded a mean temperature of 26 °C (range 23-29.5 °C), which is consistent with the mean and range of mean annual temperatures (MAT) in the region today. Paired measurements of ostracods, gastropods, and gypsum hydration water samples were measured in cores from Lake Petén Itzá, Guatemala, spanning the Late Glacial and early Holocene period (18.5-10.4 ka). The lowest recorded temperatures occurred at the start of Heinrich Stadial (HS) 1 at 18.5 ka. Inferred temperatures from benthic ostracods ranged from 16 to 20 °C during HS 1, which is 6-10 °C cooler than MAT in the region today, whereas temperatures derived from shallow-water gastropods were generally warmer (20-25 °C), reflecting epilimnetic temperatures. The derived temperatures support previous findings of greater tropical cooling on land in Central America during the Late Glacial than indicated by nearby marine records. Temperature increased in two steps during the last deglaciation. The first occurred during the Bolling-Allerod (B-A; from 14.7 to 13 ka) when temperature rose to 20-24 °C towards the end of this period. The second step occurred at 10.4 ka near the beginning of the Holocene when ostracod-inferred temperature rose to 26 °C, reflecting modern hypolimnetic temperature set during winter, whereas

Evaluation of surface detail reproduction, dimensional stability and gypsum compatibility of monophase polyvinyl-siloxane and polyether elastomeric impression materials under dry and moist conditions

PubMed Central

Vadapalli, Sriharsha Babu; Atluri, Kaleswararao; Putcha, Madhu Sudhan; Kondreddi, Sirisha; Kumar, N. Suman; Tadi, Durga Prasad

2016-01-01

Objectives: This in vitro study was designed to compare polyvinyl-siloxane (PVS) monophase and polyether (PE) monophase materials under dry and moist conditions for properties such as surface detail reproduction, dimensional stability, and gypsum compatibility. Materials and Methods: Surface detail reproduction was evaluated using two criteria. Dimensional stability was evaluated according to American Dental Association (ADA) specification no. 19. Gypsum compatibility was assessed by two criteria. All the samples were evaluated, and the data obtained were analyzed by a two-way analysis of variance (ANOVA) and Pearson's Chi-square tests. Results: When surface detail reproduction was evaluated with modification of ADA specification no. 19, both the groups under the two conditions showed no significant difference statistically. When evaluated macroscopically both the groups showed statistically significant difference. Results for dimensional stability showed that the deviation from standard was significant among the two groups, where Aquasil group showed significantly more deviation compared to Impregum group (P < 0.001). Two conditions also showed significant difference, with moist conditions showing significantly more deviation compared to dry condition (P < 0.001). The results of gypsum compatibility when evaluated with modification of ADA specification no. 19 and by giving grades to the casts for both the groups and under two conditions showed no significant difference statistically. Conclusion: Regarding dimensional stability, both impregum and aquasil performed better in dry condition than in moist; impregum performed better than aquasil in both the conditions. When tested for surface detail reproduction according to ADA specification, under dry and moist conditions both of them performed almost equally. When tested according to macroscopic evaluation, impregum and aquasil performed significantly better in dry condition compared to moist condition. In dry

Evaluation of surface detail reproduction, dimensional stability and gypsum compatibility of monophase polyvinyl-siloxane and polyether elastomeric impression materials under dry and moist conditions.

PubMed

Vadapalli, Sriharsha Babu; Atluri, Kaleswararao; Putcha, Madhu Sudhan; Kondreddi, Sirisha; Kumar, N Suman; Tadi, Durga Prasad

2016-01-01

This in vitro study was designed to compare polyvinyl-siloxane (PVS) monophase and polyether (PE) monophase materials under dry and moist conditions for properties such as surface detail reproduction, dimensional stability, and gypsum compatibility. Surface detail reproduction was evaluated using two criteria. Dimensional stability was evaluated according to American Dental Association (ADA) specification no. 19. Gypsum compatibility was assessed by two criteria. All the samples were evaluated, and the data obtained were analyzed by a two-way analysis of variance (ANOVA) and Pearson's Chi-square tests. When surface detail reproduction was evaluated with modification of ADA specification no. 19, both the groups under the two conditions showed no significant difference statistically. When evaluated macroscopically both the groups showed statistically significant difference. Results for dimensional stability showed that the deviation from standard was significant among the two groups, where Aquasil group showed significantly more deviation compared to Impregum group (P < 0.001). Two conditions also showed significant difference, with moist conditions showing significantly more deviation compared to dry condition (P < 0.001). The results of gypsum compatibility when evaluated with modification of ADA specification no. 19 and by giving grades to the casts for both the groups and under two conditions showed no significant difference statistically. Regarding dimensional stability, both impregum and aquasil performed better in dry condition than in moist; impregum performed better than aquasil in both the conditions. When tested for surface detail reproduction according to ADA specification, under dry and moist conditions both of them performed almost equally. When tested according to macroscopic evaluation, impregum and aquasil performed significantly better in dry condition compared to moist condition. In dry condition, both the materials performed almost equally. In

Systemwide board assessment.

PubMed

Hafertepe, E C

1987-01-01

The Sisters of Charity Health Care System (SCHCS), Inc., Cincinnati, undertook a systemwide board evaluation project to support and enhance effective aspects of governance and to deal with obstacles that often arise due to differing beliefs and role confusion. A task force of chief executive officers developed the questionnaire, which was then administered to members of individual facilities' boards and the system's board. The documented highlighted value issues important to SCHCS's ministry and business activities: overall board responsibilities, financial responsibilities, strategic planning, the board's role, committee structures, the board's operating process, board education, and overall board effectiveness. The responses from each member were returned to the local boards, who analyzed them and developed an action plan. A summary of each facility's responses and action plans were forwarded to the system's corporate office. The CEO committee critiqued the process and reported on significant issues and action plans. In general, survey results revealed a strong influence of mission and philosophy in decision making, support for current processes, and effective interaction among board members. The system's corporate office will use the responses to respond to a dynamic environment and strengthen their role in the delivery of Catholic health care services.

Risk of groundwater inrush in subterranean gypsum quarries: the case study of Moncalvo near Asti (North Italy)

NASA Astrophysics Data System (ADS)

Banzato, Cinzia; Fiorucci, Adriano; Gianotti, Alberto; de Waele, Jo; Vigna, Bartolomeo

2010-05-01

During the realisation of underground excavations in gypsum bedrock there is a possibility of intercepting large karst voids that can be completely filled with water under a considerable hydraulic pressure. The casual breaching of such voids can cause sudden and abundant water inrushes with consequences concerning safety of the excavation area and flooding of the tunnels. The presence of air-filled caves of great dimensions can also cause problems related to collapse of walls, ceilings and floors. In the subterranean quarry of Moncalvo d'Asti (Central Piedmont, Italy) in January 2005 an important inrush (60,000 m3 overnight) occurred causing damage to machinery and the flooding of several kilometres of underground tunnels. This inrush was caused by the breaching of a thin diaphragm of rock that separated the quarry from a large water-filled cave with water pressure of around 300 kPa along the front of the excavation. The rapid emptying of this void has caused a partial collapse of the roof of one of the largest cave chambers with the formation at the surface of a 20 metre wide sinkhole. To prevent similar phenomena to happen in the future a hydrogeological study concerning the entire gypsum mass was carried out. These investigations included monitoring of water levels intercepted by a series of boreholes, measurements of flow rates of water veins encountered by the excavations and chemical analysis of the different types of water coming from several points. This study has evidenced the presence of different drainage networks and the existence of a main karst circuit fed by diffused infiltration and recharge from the overlying marly-silty deposits and from adjacent minor less karstified systems in particularly fractured sectors of the gypsum. The waters coming from the main karst circuit are chemically very different from the waters deriving from deeper pathways. To be able to continue the excavation of gypsum in safe conditions the water levels were lowered for a

A new method for the characterization of the degree of fire damage to gypsum wallboard for use in fire investigations.

PubMed

Gorbett, Gregory E; Morris, Sarah M; Meacham, Brian J; Wood, Christopher B

2015-01-01

A new method to characterize the degree of fire damage to gypsum wallboard is introduced, implemented, and tested to determine the efficacy of its application among novices. The method was evaluated by comparing degree of fire damage assessments of novices with and without the method. Thirty-nine "novice" raters assessed damage to a gypsum wallboard surface, completing 66 ratings, first without the method, and then again using the method. The inter-rater reliability was evaluated for ratings of damage without and with the method. For novice fire investigators rating degree of damage without the aid of the method, ICC(1,2) = 0.277 with 95% CI (0.211, 0.365), and with the method, ICC(2,1) = 0.593 with 95% CI (0.509, 0.684). Results indicate that the raters were more reliable in their analysis of the degree of fire damage when using the method, which support the use of standardized processes to decrease the variability in data collection and interpretation. © 2014 American Academy of Forensic Sciences.

24 CFR 3280.206 - Fireblocking.

Code of Federal Regulations, 2011 CFR

2011-04-01

... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Fire Safety § 3280.206 Fireblocking. (a... materials: (1) Minimum one inch nominal lumber, 5/16 inch thick gypsum board, or equivalent fire resistive...

24 CFR 3280.206 - Fireblocking.

Code of Federal Regulations, 2012 CFR

2012-04-01

... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Fire Safety § 3280.206 Fireblocking. (a... materials: (1) Minimum one inch nominal lumber, 5/16 inch thick gypsum board, or equivalent fire resistive...

24 CFR 3280.206 - Fireblocking.

Code of Federal Regulations, 2014 CFR

2014-04-01

... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Fire Safety § 3280.206 Fireblocking. (a... materials: (1) Minimum one inch nominal lumber, 5/16 inch thick gypsum board, or equivalent fire resistive...

24 CFR 3280.206 - Fireblocking.

Code of Federal Regulations, 2010 CFR

2010-04-01

... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Fire Safety § 3280.206 Fireblocking. (a... materials: (1) Minimum one inch nominal lumber, 5/16 inch thick gypsum board, or equivalent fire resistive...

24 CFR 3280.206 - Fireblocking.

Code of Federal Regulations, 2013 CFR

2013-04-01

... DEVELOPMENT MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS Fire Safety § 3280.206 Fireblocking. (a... materials: (1) Minimum one inch nominal lumber, 5/16 inch thick gypsum board, or equivalent fire resistive...

32 CFR 644.450 - Items excluded from usual restoration obligation.

Code of Federal Regulations, 2011 CFR

2011-07-01

... gypsum block walls. (3) Floor joints, roof trusses (including roof boards and roofing), and framing..., ventilators, and metal ceilings. (8) Structural steel or iron. (9) Fire escapes. (10) Heating systems. (11...

32 CFR 644.450 - Items excluded from usual restoration obligation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... gypsum block walls. (3) Floor joints, roof trusses (including roof boards and roofing), and framing..., ventilators, and metal ceilings. (8) Structural steel or iron. (9) Fire escapes. (10) Heating systems. (11...

Collapse susceptibility mapping in karstified gypsum terrain (Sivas basin - Turkey) by conditional probability, logistic regression, artificial neural network models

NASA Astrophysics Data System (ADS)

Yilmaz, Isik; Keskin, Inan; Marschalko, Marian; Bednarik, Martin

2010-05-01

This study compares the GIS based collapse susceptibility mapping methods such as; conditional probability (CP), logistic regression (LR) and artificial neural networks (ANN) applied in gypsum rock masses in Sivas basin (Turkey). Digital Elevation Model (DEM) was first constructed using GIS software. Collapse-related factors, directly or indirectly related to the causes of collapse occurrence, such as distance from faults, slope angle and aspect, topographical elevation, distance from drainage, topographic wetness index- TWI, stream power index- SPI, Normalized Difference Vegetation Index (NDVI) by means of vegetation cover, distance from roads and settlements were used in the collapse susceptibility analyses. In the last stage of the analyses, collapse susceptibility maps were produced from CP, LR and ANN models, and they were then compared by means of their validations. Area Under Curve (AUC) values obtained from all three methodologies showed that the map obtained from ANN model looks like more accurate than the other models, and the results also showed that the artificial neural networks is a usefull tool in preparation of collapse susceptibility map and highly compatible with GIS operating features. Key words: Collapse; doline; susceptibility map; gypsum; GIS; conditional probability; logistic regression; artificial neural networks.

Microbial volatile organic compound emissions from Stachybotrys chartarum growing on gypsum wallboard and ceiling tile

PubMed Central

2013-01-01

Background Stachybotrys chartarum is a filamentous mold frequently identified among the mycobiota of water-damaged building materials. Growth of S. chartarum on suitable substrates and under favorable environmental conditions leads to the production of secondary metabolites such as mycotoxins and microbial volatile organic compounds (MVOCs). The aim of this study was to characterize MVOC emission profiles of seven toxigenic strains of S. chartarum, isolated from water-damaged buildings, in order to identify unique MVOCs generated during growth on gypsum wallboard and ceiling tile coupons. Inoculated coupons were incubated and monitored for emissions and growth using a closed glass environmental growth chamber maintained at a constant room temperature. Gas samples were collected from the headspace for three to four weeks using Tenax TA tubes. Results Most of the MVOCs identified were alcohols, ketones, ethers and esters. The data showed that anisole (methoxybenzene) was emitted from all of the S. chartarum strains tested on both types of substrates. Maximum anisole concentration was detected after seven days of incubation. Conclusions MVOCs are suitable markers for fungal identification because they easily diffuse through weak barriers like wallpaper, and could be used for early detection of mold growth in hidden cavities. This study identifies the production of anisole by seven toxigenic strains of Stachybotrys chartarum within a period of one week of growth on gypsum wallboard and ceiling tiles. These data could provide useful information for the future construction of a robust MVOC library for the early detection of this mold. PMID:24308451

Getting boards on board a major challenge for integrated systems.

PubMed

Egger, E

1998-12-01

Among the challenges an integrated health care system faces is helping its board members make the transition away from a historic community philanthropic board toward a board with more of a business approach.

Arsenic speciation in synthetic gypsum (CaSO4·2H2O): A synchrotron XAS, single-crystal EPR, and pulsed ENDOR study

NASA Astrophysics Data System (ADS)

Lin, Jinru; Chen, Ning; Nilges, Mark J.; Pan, Yuanming

2013-04-01

Gypsum (CaSO4·2H2O) is a major by-product of mining and milling processes of borate, phosphate and uranium deposits worldwide and, therefore, potentially plays an important role in the stability and bioavailability of heavy metalloids, including As, in tailings and surrounding areas. Gypsum containing 1900 and 185 ppm As, synthesized with Na2HAsO4·7H2O and NaAsO2 in the starting materials, respectively, have been investigated by synchrotron X-ray absorption spectroscopy (XAS), single-crystal electron paramagnetic resonance spectroscopy (EPR), and pulsed electron nuclear double resonance spectroscopy (ENDOR). Quantitative analyses of As K edge XANES and EXAFS spectra show that arsenic occurs in both +3 and +5 oxidation states and the As3+/As5+ value varies from 0.35 to 0.79. Single-crystal EPR spectra of gamma-ray-irradiated gypsum reveal two types of arsenic-associated oxyradicals: [AsO3]2- and an [AsO2]2-. The [AsO3]2- center is characterized by principal 75As hyperfine coupling constants of A1 = 1952.0(2) MHz, A2 = 1492.6(2) MHz and A3 = 1488.7(2) MHz, with the unique A axis along the S-O1 bond direction, and contains complex 1H superhyperfine structures that have been determined by pulsed ENDOR. These results suggest that the [AsO3]2- center formed from electron trapping on the central As5+ ion of a substitutional (AsO4)3- group after removal of an O1 atom. The [AsO2]2- center is characterized by its unique A(75As) axis approximately perpendicular to the O1-S-O2 plane and the A2 axis along the S-O2 bond direction, consistent with electron trapping on the central As3+ ion of a substitutional (AsO3)3- group after removal of an O2 atom. These results confirm lattice-bound As5+ and As3+ in gypsum and point to potential application of this mineral for immobilization and removal of arsenic pollution.

Production development and utilization of Zimmer Station wet FGD by-products. Final report. Volume 5, A laboratory greenhouse study conducted in fulfillment of Phase 2, Objective 2 titled. Use of FGD by-product gypsum enriched with magnesium hydroxide as a soil amendment

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

Yibirin, H.; Stehouwer, R. C.; Bigham, J. M.

The Clean Air Act, as revised in 1992, has spurred the development of flue gas desulfurization (FGD) technologies that have resulted in large volumes of wet scrubber sludges. In general, these sludges must be dewatered, chemically treated, and disposed of in landfills. Disposal is an expensive and environmentally questionable process for which suitable alternatives must be found. Wet scrubbing with magnesium (Mg)-enhanced lime has emerged as an efficient, cost effective technology for SO 2 removal. When combined with an appropriate oxidation system, the wet scrubber sludge can be used to produce gypsum (CaSO 4-2H 2O) and magnesium hydroxide [Mg(OH) 2]more » of sufficient purity for beneficial re-use. Product value generally increases with purity of the by-product(s). The pilot plant at the CINERGY Zimmer Station near Cincinnati produces gypsum by products that can be formulated to contain varying amounts of Mg(OH) 2. Such materials may have agricultural value as soil conditioners, liming agents and sources of plant nutrients (Ca, Mg, S). This report describes a greenhouse study designed to evaluate by-product gypsum and Mg gypsum from the Zimmer Station pilot plant as amendments for improving the quality of agricultural soils and mine spoils that are currently unproductive because of phytotoxic conditions related to acidity and high levels of toxic dissolved aluminum (Al). In particular, the technical literature contains evidence to suggest that gypsum may be more effective than agricultural limestone in modifying soil chemical conditions below the immediate zone of application. Representative samples of by-product gypsum and Mg(OH) 2 from the Zimmer Station were initially characterized. The gypsum was of high chemical purity and consisted of well crystalline, lath-shaped particles of low specific surface area. By contrast, the by-product Mg(OH) 2 was a high surface area material (50 m 2 g -1) that contained 20% CaSO 4 with variable hydration state. Artificial

Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

NASA Technical Reports Server (NTRS)

Muirhead, Dean; Carrier, Christopher

2012-01-01

In this study, three different mineral acids were substituted for sulfuric acid (H2SO4) in the urine stabilizer solution to eliminate the excess of sulfate ions in pretreated urine and assess the impact on maximum water recovery to avoid precipitation of minerals during distillation. The study evaluated replacing 98% sulfuric acid with 85% phosphoric acid (H3PO4), 37% hydrochloric acid (HCl), or 70% nitric acid (HNO3). The effect of lowering the oxidizer concentration in the pretreatment formulation also was studied. This paper summarizes the test results, defines candidate formulations for further study, and specifies the injection masses required to stabilize urine and minimize the risk of mineral precipitation during distillation. In the first test with a brine ersatz acidified with different acids, the solubility of calcium in gypsum saturated solutions was measured. The solubility of gypsum was doubled in the brines acidified with the alternative acids compared to sulfuric acid. In a second series of tests, the alternative acid pretreatment concentrations were effective at preventing precipitation of gypsum and other minerals up to 85% water recovery from 95th-percentile pretreated, augmented urine. Based on test results, phosphoric acid is recommended as the safest alternative to sulfuric acid. It also is recommended that the injected mass concentration of chromium trioxide solution be reduced by 75% to minimize liquid resupply mass by about 50%, reduce toxicity of brines, and reduce the concentration of organic acids in distillate. The new stabilizer solution formulations and required doses to stabilize urine and prevent precipitation of minerals up to 85% water recovery are given. The formulations in this study were tested on a limited number of artificially augmented urine batches collected from employees at the Johnson Space Center (JSC). This study successfully demonstrated that the desired physical and chemical stability of pretreated urine and brines

Hospital board effectiveness: relationships between board training and hospital financial viability.

PubMed

Molinari, C; Morlock, L; Alexander, J; Lyles, C A

1992-01-01

This study examined whether hospital governing boards that invest in board education and training are more informed and effective decision-making bodies. Measures of hospital financial viability (i.e., selected financial ratios and outcomes) are used as indicators of hospital board effectiveness. Board participation in educational programs was significantly associated with improved profitability, liquidity, and occupancy levels, suggesting that investment in the education of directors is likely to enhance hospital viability and thus increase board effectiveness.

Illustrative Bylaws for Public College and University Governing Boards. Board Basics

ERIC Educational Resources Information Center

Ingram, Tom; Johnson, Neal

2005-01-01

Bylaws constitute one of the most important legal documents in the portfolio of a public college or university board. They articulate the board?s responsibilities and establish the "rules" by which the board organizes itself to do its work. Bylaws begin where a public institution's statutes or constitutional provisions leave off. They build on…

Mold Image Library

MedlinePlus

... condensation because there is a hole in the insulation and it is cold outdoors. Photo courtesy of ... Inside of wall from above, moldy gypsum board, insulation Photo courtesy of Terry Brennan Looking for mold ...

Learning Medical Microbiology and Infectious Diseases by Means of a Board Game: Can It Work?

ERIC Educational Resources Information Center

Struwig, Magdalena C.; Beylefeld, Adriana A.; Joubert, Georgina

2014-01-01

Innovative teaching and learning is increasingly becoming part of medical education. We report the evaluation of a medical microbiology board game, Med Micro Fun With Facts (MMFWF), based on Trivial Pursuit™ principles. The game was developed to stimulate medical students' interest in microbiology and expose students to the subject content of an…

[Hand-arm vibration syndrome in a nurse carrying out gypsum cutting operations].

PubMed

Speziale, Martina; Picchiotti, E

2009-01-01

A professional nurse, employed mainly on gypsum cutting operations, developed a hand-arm vibration syndrome with Raynaud's phenomenon, neurosensitive disorders and impairment of the bone and joints apparatus of the hand and arm. The nurse underwent diagnostic investigations (cold test, X-ray of the upper limbs, blood tests); also the vibration levels transmitted from instrument were measured and the exposure times were established. Clinical investigations showed the presence of a hand-arm vibration syndrome with secondary Raynaud's phenomenon and environmental surveys revealed very high vibration levels, such as could be associated with the disease with a causal relationship. In the literature no reports exist of the vibration syndrome being associated with health care workers in orthopaedic departments. The case described in this study occurred because of peculiar organisational factors that most likely have never occurred in other hospitals or orthopaedic departments.

Gypsum, jarosite, and hydrous iron-phosphate in Martian meteorite Roberts Massif 04262: Implications for sulfate geochemistry on Mars.

NASA Astrophysics Data System (ADS)

Greenwood, J. P.

2008-12-01

Gypsum has been identified on Mars by MEX OMEGA [1] and jarosite identified via MER-B lander [2] and both minerals are examples of the importance of calcium and iron sulfates in Martian weathering processes. The weathering of Martian basalt to form Ca and iron sulfates should be an important process on Mars. Martian jarosite has been identified in MIL 03346 [3] and Ca-sulfate has been identified in EETA 79001 [4], but both phases have yet to be identified in the same Martian sample. In Roberts Massif 04262, an olivine-phyric shergottite, iron-sulfide and calcium-phosphate minerals are undergoing reaction (dissolution and reprecipitation?) to form gypsum, jarosite, and an iron-phosphate phase, presumably during the meteorite's residence in Antarctica. If true, then an acidic and oxidizing fluid was present in this meteorite, due to the formation of jarosite which requires fluid of this type to form [5]. The weathering of iron-sulfides on Earth to form acidic and oxidizing fluids is common, thus this can be reconciled with the formation of an acidic fluid in a basic rock. Presumably, under more extensive weathering of silicate minerals in Martian basalt, the pH would be raised to values where jarosite would not be stable. While the weathering of RBT 04262 is likely occurring in Antarctica, a similar susceptibility of the apatite and pyrrhotite to incipient weathering on Mars may be expected. Oxidizing crustal fluids on Mars may attack iron- sulfides first in Martian basalts. The weathering of iron-sulfides leads to increasing acidity of fluids, which would enhance the dissolution of the calcium-phosphate minerals [6]. The formation of jarosite, gypsum, and iron-phosphate minerals during the early stages of weathering of Martian basalts may be an important process on Mars globally. [1] Gendrin, A. et al. (2005) Science, 307, 1587-1591. [2] Klingelhöfer et al. (2004) Science, 306, 1740- 1745. [3] Vicenzi E. P. et al. (2007) LPSC XXXVIII, Abstract 2335. [4] Gooding J

Successful lichen translocation on disturbed gypsum areas: A test with adhesives to promote the recovery of biological soil crusts

NASA Astrophysics Data System (ADS)

Ballesteros, M.; Ayerbe, J.; Casares, M.; Cañadas, E. M.; Lorite, J.

2017-04-01

The loss of biological soil crusts represents a challenge for the restoration of disturbed environments, specifically in particular substrates hosting unique lichen communities. However, the recovery of lichen species affected by mining is rarely addressed in restoration projects. Here, we evaluate the translocation of Diploschistes diacapsis, a representative species of gypsum lichen communities affected by quarrying. We tested how a selection of adhesives could improve thallus attachment to the substrate and affect lichen vitality (as CO2 exchange and fluorescence) in rainfall-simulation and field experiments. Treatments included: white glue, water, hydroseeding stabiliser, gum arabic, synthetic resin, and a control with no adhesive. Attachment differed only in the field, where white glue and water performed best. Adhesives altered CO2 exchange and fluorescence yield. Notably, wet spoils allowed thalli to bind to the substrate after drying, revealing as the most suitable option for translocation. The satisfactory results applying water on gypsum spoils are encouraging to test this methodology with other lichen species. Implementing these measures in restoration projects would be relatively easy and cost-effective. It would help not only to recover lichen species in the disturbed areas but also to take advantage of an extremely valuable biological material that otherwise would be lost.

Simultaneous and continuous stabilization of As and Pb in contaminated solution and soil by a ferrihydrite-gypsum sorbent.

PubMed

Kameda, Kentaro; Hashimoto, Yohey; Wang, Shan-Li; Hirai, Yasumasa; Miyahara, Hidetaka

2017-04-05

For the increasing need of stabilization both cationic and anionic metal(loid)s simultaneously, we newly developed a metal sorbent (FIXALL), consisting mainly of ferrihydrite and gypsum. The objectives of this study were to determine the molecular mechanisms of Pb and As stabilization in an aqueous system and to examine a simultaneous and long-term (up to 754days) effect on Pb and As stabilization in an anthropogenically contaminated soil using the FIXALL sorbent. When the solution contained a low concentration of Pb (5mgL -1 ), the mechanisms of Pb removal by FIXALL were based chiefly on the formation of inner-sphere surface complex with ferrihydrite. In the highly concentrated Pb solution (1200mgL -1 ), contrarily, the removal of Pb by FIXALL was the direct consequence of the dissolution of gypsum and subsequent precipitation of PbSO 4 , which strengthens the drawback of low capability of ferrihydrite for Pb removal. Regardless of initial concentrations, the primary mechanism of FIXALL for As stabilization is attributed to the formation of inner-sphere surface complex with ferrihydrite. A contaminated soil study demonstrated that FIXALL could decrease the concentration of water soluble As and Pb simultaneously and continuously for 754days without notable changes in their chemical species and soil pH. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of an Adjustable board and a Rotational Board for Scaffold

NASA Astrophysics Data System (ADS)

Jang, Myunghoun

2017-06-01

Scaffold is widely used in high work-places inside and outside of a building construction site. It is inexpensive and is installed and dismantled easily. Although standards and ledgers of a steel tube and coupler scaffold are installed in a regular distance, the distances of transoms are not equal in some places. Sometimes a working platform or a board is absent in the corner of scaffold. This may cause safety accidents because a foothold is not stable on the transoms. An adjustable safety board and a rotational safety board are suggested in this paper. The adjustable board consists of two footholds. The small one is inserted into the large one. The rotational board covers not only right angle but also acute or obtuse angles. These safety boards for scaffold help to decrease safety accidents in construction sites.

Prediction of halite, gypsum, and anhydrite solubility in natural brines under subsurface conditions

NASA Astrophysics Data System (ADS)

He, Shiliang; Morse, John W.

1993-01-01

Prediction of the solubility of the evaporite minerals halite, gypsum, and anhydrite in brines has numerous scientific and practical applications. This paper presents a Pitzer equation-based model for predicting the solubility of these minerals in Na +-K +-H +-Ca 2+-Mg 2+-Cl --OH --SO 42--H 2O solutions of varying composition as a function of temperature and pressure. Model predictions compare well with experimental observations. As an example of the utility of this program, the volume of CaSO 4 precipitated as a brine flows up a pipe from 6000 m depth is predicted. This is done as a function of flow distance for different cooling rates of the brine. Results indicate that if the brine can be cooled to near the geothermal gradient no precipitation will take place.

The Short, Productive Board Meeting

ERIC Educational Resources Information Center

McAdams, Donald R.

2005-01-01

Board meetings are the time and place where school boards act. In fact, only when coming together as a body in a legal meeting do school board members become a board. Effective board meetings are the first prerequisite for an effective board. Furthermore, what parents and voters see at board meetings determines largely what they think about their…

Becoming a Better Board Member. A Guide to Effective School Board Service.

ERIC Educational Resources Information Center

National School Boards Association, Washington, DC.

This guide to effective school board service is a "how-to" manual for school board members. The objective of the book is to condense the time board members need to become more effective school leaders, but it also contains information and advice intended to be helpful to experienced board members. Consisting of 17 chapters, the book is…

Rare earths recovery and gypsum upgrade from Florida phosphogypsum

DOE PAGES

Liang, Haijun; Zhang, Patrick; Jin, Zhen; ...

2017-11-01

Phosphogypsum is a byproduct created during the production of industrial wet-process phosphoric acid. This study focused on recovering rare earth elements (REEs) from a Florida phosphogypsum sample and investigated the effects of removing detrimental impurities such as phosphorus pentoxide (P 2O 5), uranium (U) and fluorine (F) during the leaching process. Experimental results indicated that REE leaching efficiency increased rapidly, reached a maximum and then began to decrease with sulfuric acid concentrations ranging from 0 to 10 percent and temperatures ranging from 20 to 70 °C. At a sulfuric acid concentration of 5 percent and leaching temperature of 50 °C,more » REE leaching efficiency obtained a maximum value of approximately 43 percent. Increasing the leaching time or liquid/solid ratio increased the leaching efficiency. The leaching efficiencies of P 2O 5, U and F consistently increased with sulfuric acid concentration, temperature, leaching time and liquid/solid ratio within the testing ranges. A fine-grain gypsum concentrate, sized smaller than 40 μm, was separated from leached phosphogypsum through elutriation, in which the P 2O 5, U and F content levels were reduced by 99, 70 and 83 percent, respectively, from their content levels in fresh phosphogypsum.« less

Rare earths recovery and gypsum upgrade from Florida phosphogypsum

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

Liang, Haijun; Zhang, Patrick; Jin, Zhen

Phosphogypsum is a byproduct created during the production of industrial wet-process phosphoric acid. This study focused on recovering rare earth elements (REEs) from a Florida phosphogypsum sample and investigated the effects of removing detrimental impurities such as phosphorus pentoxide (P 2O 5), uranium (U) and fluorine (F) during the leaching process. Experimental results indicated that REE leaching efficiency increased rapidly, reached a maximum and then began to decrease with sulfuric acid concentrations ranging from 0 to 10 percent and temperatures ranging from 20 to 70 °C. At a sulfuric acid concentration of 5 percent and leaching temperature of 50 °C,more » REE leaching efficiency obtained a maximum value of approximately 43 percent. Increasing the leaching time or liquid/solid ratio increased the leaching efficiency. The leaching efficiencies of P 2O 5, U and F consistently increased with sulfuric acid concentration, temperature, leaching time and liquid/solid ratio within the testing ranges. A fine-grain gypsum concentrate, sized smaller than 40 μm, was separated from leached phosphogypsum through elutriation, in which the P 2O 5, U and F content levels were reduced by 99, 70 and 83 percent, respectively, from their content levels in fresh phosphogypsum.« less

Surface modification of calcium sulfate whisker prepared from flue gas desulfurization gypsum

NASA Astrophysics Data System (ADS)

Liu, Chengjun; Zhao, Qing; Wang, Yeguang; Shi, Peiyang; Jiang, Maofa

2016-01-01

In order to obtain hydrophobic whisker for preparing polymeric composite product, the calcium sulfate whisker (CSW) prepared from flue gas desulfurization (FGD) gypsum by hydrothermal synthesis was modified by various surfactants, and the effects of some modification conditions on the hydrophobic property of CSW were investigated in this study. Sodium stearate was considered to be a suitable surfactant and its reasonable dosage was 2% of ethanol solvent. Both physical and chemical absorptions were found in the surface modification process, and the later one was suggested to preferentially occur on the CSW surface. Moreover, modifying temperature, modifying duration, and agitation speed were experimentally found to have a remarkable influence on the modification behavior. Active ratio reached 0.845 when the modification process was conducted under reasonable conditions obtained in the current work. Finally, polypropylene sheet products were prepared from modified CSW showing an excellence mechanical property.

The Vanishing School Board.

ERIC Educational Resources Information Center

Chalker, Donald M.; Haynes, Richard M.

1997-01-01

Now that school boards have been replaced by parent advisory councils, there is virtually no local school governance in New Brunswick, Canada. Factors leading to school boards' demise include neglected democratic institutions, failure to understand local boards' needs, less qualified members, boards' failure to protect their special…

7 CFR 1160.105 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... and Orders; Milk), DEPARTMENT OF AGRICULTURE FLUID MILK PROMOTION PROGRAM Fluid Milk Promotion Order Definitions § 1160.105 Board. Board means the National Processor Advertising and Promotion Board established... Promotion Board or Board). ...

Board task performance: An exploration of micro- and macro-level determinants of board effectiveness

PubMed Central

Minichilli, Alessandro; Zattoni, Alessandro; Nielsen, Sabina; Huse, Morten

2012-01-01

This paper addresses recent calls to narrow the micro–macro gap in management research (Bamberger, 2008), by incorporating a macro-level context variable (country) in exploring micro-level determinants of board effectiveness. Following the integrated model proposed by Forbes and Milliken (1999), we identify three board processes as micro-level determinants of board effectiveness. Specifically, we focus on effort norms, cognitive conflicts and the use of knowledge and skills as determinants of board control and advisory task performance. Further, we consider how two different institutional settings influence board tasks, and how the context moderates the relationship between processes and tasks. Our hypotheses are tested on a survey-based dataset of 535 medium-sized and large industrial firms in Italy and Norway, which are considered to substantially differ along legal and cultural dimensions. The findings show that: (i) Board processes have a larger potential than demographic variables to explain board task performance; (ii) board task performance differs significantly between boards operating in different contexts; and (iii) national context moderates the relationships between board processes and board task performance. Copyright © 2010 John Wiley & Sons, Ltd. PMID:23365485

Characterization of bacterial diversity associated with microbial mats, gypsum evaporites and carbonate microbialites in thalassic wetlands: Tebenquiche and La Brava, Salar de Atacama, Chile.

PubMed

Farías, M E; Contreras, M; Rasuk, M C; Kurth, D; Flores, M R; Poiré, D G; Novoa, F; Visscher, P T

2014-03-01

In this paper, we report the presence of sedimentary microbial ecosystems in wetlands of the Salar de Atacama. These laminated systems, which bind, trap and precipitate mineral include: microbial mats at Laguna Tebenquiche and Laguna La Brava, gypsum domes at Tebenquiche and carbonate microbialites at La Brava. Microbial diversity and key biogeochemical characteristics of both lakes (La Brava and Tebenquiche) and their various microbial ecosystems (non-lithifying mats, flat and domal microbialites) were determined. The composition and abundance of minerals ranged from trapped and bound halite in organic-rich non-lithifying mats to aragonite-dominated lithified flat microbialites and gypsum in lithified domal structures. Pyrosequencing of the V4 region of the 16s rDNA gene showed that Proteobacteria comprised a major phylum in all of the microbial ecosystems studied, with a marked lower abundance in the non-lithifying mats. A higher proportion of Bacteroidetes was present in Tebenquiche sediments compared to La Brava samples. The concentration of pigments, particularly that of Chlorophyll a, was higher in the Tebenquiche than in La Brava. Pigments typically associated with anoxygenic phototrophic bacteria were present in lower amounts. Organic-rich, non-lithifying microbial mats frequently formed snake-like, bulbous structures due to gas accumulation underneath the mat. We hypothesize that the lithified microbialites might have developed from these snake-like microbial mats following mineral precipitation in the surface layer, producing domes with endoevaporitic communities in Tebenquiche and carbonate platforms in La Brava. Whereas the potential role of microbes in carbonate platforms is well established, the contribution of endoevaporitic microbes to formation of gypsum domes needs further investigation.

The impact of the board's strategy-setting role on board-management relations and hospital performance.

PubMed

Büchner, Vera Antonia; Schreyögg, Jonas; Schultz, Carsten

2014-01-01

The appropriate governance of hospitals largely depends on effective cooperation between governing boards and hospital management. Governing boards play an important role in strategy-setting as part of their support for hospital management. However, in certain situations, this active strategic role may also generate discord within this relationship. The objective of this study is to investigate the impact of the roles, attributes, and processes of governing boards on hospital performance. We examine the impact of the governing board's strategy-setting role on board-management collaboration quality and on financial performance while also analyzing the interaction effects of board diversity and board activity level. The data are derived from a survey that was sent simultaneously to German hospitals and their associated governing board, combined with objective performance information from annual financial statements and quality reports. We use a structural equation modeling approach to test the model. The results indicate that different board characteristics have a significant impact on hospital performance (R = .37). The strategy-setting role and board-management collaboration quality have a positive effect on hospital performance, whereas the impact of strategy-setting on collaboration quality is negative. We find that the positive effect of strategy-setting on performance increases with decreasing board diversity. When board members have more homogeneous backgrounds and exhibit higher board activity levels, the negative effect of the strategy-setting on collaboration quality also increases. Active strategy-setting by a governing board may generally improve hospital performance. Diverse members of governing boards should be involved in strategy-setting for hospitals. However, high board-management collaboration quality may be compromised if managerial autonomy is too highly restricted. Consequently, hospitals should support board-management collaboration about

Scrum Board Game

NASA Astrophysics Data System (ADS)

van den Oord, Stefan; van de Goor, Wim

The Scrum Board Game is a workshop for beginners. It is for people with any role (customer, developer, tester, etc.), who don’t exactly know what a Scrum Board is, or how to create one themselves. The workshop teaches the benefits of a Scrum Board, how to use it, and how to introduce it in projects.

Water of Hydration Dynamics in Minerals Gypsum and Bassanite: Ultrafast 2D IR Spectroscopy of Rocks.

PubMed

Yan, Chang; Nishida, Jun; Yuan, Rongfeng; Fayer, Michael D

2016-08-03

Water of hydration plays an important role in minerals, determining their crystal structures and physical properties. Here ultrafast nonlinear infrared (IR) techniques, two-dimensional infrared (2D IR) and polarization selective pump-probe (PSPP) spectroscopies, were used to measure the dynamics and disorder of water of hydration in two minerals, gypsum (CaSO4·2H2O) and bassanite (CaSO4·0.5H2O). 2D IR spectra revealed that water arrangement in freshly precipitated gypsum contained a small amount of inhomogeneity. Following annealing at 348 K, water molecules became highly ordered; the 2D IR spectrum became homogeneously broadened (motional narrowed). PSPP measurements observed only inertial orientational relaxation. In contrast, water in bassanite's tubular channels is dynamically disordered. 2D IR spectra showed a significant amount of inhomogeneous broadening caused by a range of water configurations. At 298 K, water dynamics cause spectral diffusion that sampled a portion of the inhomogeneous line width on the time scale of ∼30 ps, while the rest of inhomogeneity is static on the time scale of the measurements. At higher temperature, the dynamics become faster. Spectral diffusion accelerates, and a portion of the lower temperature spectral diffusion became motionally narrowed. At sufficiently high temperature, all of the dynamics that produced spectral diffusion at lower temperatures became motionally narrowed, and only homogeneous broadening and static inhomogeneity were observed. Water angular motions in bassanite exhibit temperature-dependent diffusive orientational relaxation in a restricted cone of angles. The experiments were made possible by eliminating the vast amount of scattered light produced by the granulated powder samples using phase cycling methods.

Training memory without aversion: Appetitive hole-board spatial learning increases adult hippocampal neurogenesis.

PubMed

Sampedro-Piquero, Patricia; Moreno-Fernández, Román D; Carmen Mañas-Padilla, M; Gil-Rodríguez, Sara; Gavito, Ana Luisa; Pavón, Francisco J; Pedraza, Carmen; García-Fernández, María; Ladrón de Guevara-Miranda, David; Santín, Luis J; Castilla-Ortega, Estela

2018-05-01

Learning experiences are potent modulators of adult hippocampal neurogenesis (AHN). However, the vast majority of findings on the learning-induced regulation of AHN derive from aversively-motivated tasks, mainly the water maze paradigm, in which stress is a confounding factor that affects the AHN outcome. Currently, little is known regarding the effect of appetitively-motivated training on AHN. Hence we studied how spatial learning to find food rewards in a hole-board maze modulates AHN (cell proliferation and immature neurons) and AHN-related hippocampal neuroplasticity markers (BDNF, IGF-II and CREB phosphorylation) in mice. The 'Trained' mice were tested for both spatial reference and working memory and compared to 'Pseudotrained' mice (exposed to different baited holes in each session, thus avoiding the reference memory component of the task) and 'Control' mice (exposed to the maze without rewards). In contrast to Pseudotrained and Control mice, the number of proliferating hippocampal cells were reduced in Trained mice, but they notably increased their population of immature neurons assessed by immunohistochemistry. This evidence shows that hole-board spatial reference learning diminishes cell proliferation in favor of enhancing young neurons' survival. Interestingly, the enhanced AHN in the Trained mice (specifically in the suprapyramidal blade) positively correlated with their reference memory performance, but not with their working memory. Furthermore, the Trained animals increased the hippocampal protein expression of all the neuroplasticity markers analyzed by western blot. Results show that the appetitively-motivated hole-board task is a useful paradigm to potentiate and/or investigate AHN and hippocampal plasticity minimizing aversive variables such as fear or stress. Copyright © 2018 Elsevier Inc. All rights reserved.

The Jettencave, Southern Harz Mountains, Germany: Geophysical observations and a structural model of a shallow cave in gypsum/anhydrite-bearing rocks

NASA Astrophysics Data System (ADS)

Kaufmann, Georg; Romanov, Douchko

2017-12-01

Gypsum and anhydrite are soluble rocks, where fissures and bedding partings can be enlarged with time by the dissolution of the mineral species through water. The selective enlargement results in sub-surface voids acting as preferential flow path for the drainage of the rock. With time, larger cavities develop, and a network of cave passages can evolve. If the enlarged cave voids are not too deep under the surface, geophysical measurements can be used to detect, identify and trace these structures. We have used gravity measurements (GRAV), electrical resistivity imaging (ERI), self-potential measurements (SP), electrical conductivity measurements (EC), and ground-penetrating radar (GPR) above the cave Jettenhöhle, a cave located in the southern Harz Mountains in Germany. The Jettencave is developed in the Hauptanhydrit formation of the Permian Zechstein sequence, characterised by large breakdown rooms and an exposed water table. The overburden of the cave is only around 10-15 m, and dolomitic rocks are located in close vicinity. We present results from our geophysical surveys in vicinity of the cave. We are able to identify the cave geometry from GRAV, ERI, and GPR measurements, which distinguish the local lithology of the Permian Zechstein rocks in the area. From the ERI and EC measurements, we derive information on the void volume in the soluble rocks. We finally present a three-dimensional structural model of the Jettencave and its surroundings, based on our geophysical results and the hydrological interpretation.

Motives and Power of School Board Members: Implications for School Board-Superintendent Relationships

ERIC Educational Resources Information Center

Mountford, Meredith

2004-01-01

The qualitative study presented in this article explores motivations for school board membership and conceptions of power held by school board members. The findings of the study suggest a relationship exists between the way board members define power and the type of motivation board members have for service. The implications of these findings for…

Vibration on board and health effects.

PubMed

Jensen, Anker; Jepsen, Jørgen Riis

2014-01-01

There is only limited knowledge of the exposure to vibrations of ships' crews and their risk of vibration-induced health effects. Exposure to hand-arm vibrations from the use of vibrating tools at sea does not differ from that in the land-based trades. However, in contrast to most other work places, seafarers are also exposed to vibrations to the feet when standing on vibrating surfaces on board. Anecdotal reports have related the development of "white feet" to local exposure to vibration, e.g. in mining, but this connection has not been investigated in the maritime setting. As known from studies of the health consequences of whole body vibrations in land-transportation, such exposure at sea may affect ships' passengers and crews. While the relation of back disorders to high levels of whole body vibration has been demonstrated among e.g. tractor drivers, there are no reported epidemiological evidence for such relation among seafarers except for fishermen, who, however, are also exposed to additional recognised physical risk factors at work. The assessment and reduction of vibrations by naval architects relates to technical implications of this impact for the ships' construction, but has limited value for the estimation of health risks because they express the vibration intensity differently that it is done in a medical context.

77 FR 2541 - Board Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-18

... FARM CREDIT SYSTEM INSURANCE CORPORATION Board Meeting AGENCY: Farm Credit System Insurance Corporation Board; Regular Meeting. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). DATE AND TIME: The meeting of the Board will be held at the...

EVALUATION OF SINK EFFECTS ON VOCS FROM A LATEX PAINT

EPA Science Inventory

The sink strength of two common indoor materials, a carpet and a gypsum board, was evaluated by environmental chamber tests with four volatile organic compounds (VOCs): propylene glycol, ethylene glycol, 2-(2-butoxyethoxy)ethanol (BEE), and texanol. These oxygenated compounds rep...

CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT

EPA Science Inventory

The paper discusses the measurment and analysis of the patterns of formaldehyde emission from a low volatile organic compound (VOC) latex paint applied to gypsum board, using small environmental chamber tests. The formaldehyde emissions resulted in sharp increase of chamber air...

75 FR 11210 - Public Company Accounting Oversight Board; Order Approving Proposed Amendment to Board Rules...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-10

... Accounting Oversight Board; Order Approving Proposed Amendment to Board Rules Relating to Inspections March 4, 2010. I. Introduction On July 2, 2009, the Public Company Accounting Oversight Board (the ``Board'' or...'') relating to the Board's rules governing inspections of registered public accounting firms. Notice of the...

Comprehensive Planning for Passive Solar Architectural Retrofit

DTIC Science & Technology

1980-05-01

USE WOOD , PLYWOOD, PARTICLE BOARD AND GYPSUM BOARD. USE THE FOLLOWING MATERIALS ONLY IN SMALL QUANTITIES OR WHEN THEY HAVE BEEN RE-CYCLED: STEEL...34 Your selection of good secondary/ finishing materials will, by its nature, be energy conservative. Wood is an excellent secondary material. Other...University, May 1977. 8. Denise Guerin. "Textiles in an Ecological Framework," unpub- lished graduate paper, Michigan State University, June 1976. 9

Hospital boards and hospital strategic focus: the impact of board involvement in strategic decision making.

PubMed

Ford-Eickhoff, Karen; Plowman, Donde Ashmos; McDaniel, Reuben R

2011-01-01

Despite pressures to change the role of hospital boards, hospitals have made few changes in board composition or director selection criteria. Hospital boards have often continued to operate in their traditional roles as either "monitors" or "advisors." More attention to the direct involvement of hospital boards in the strategic decision-making process of the organizations they serve, the timing and circumstances under which board involvement occurs, and the board composition that enhances their abilities to participate fully is needed. We investigated the relationship between broader expertise among hospital board members, board involvement in the stages of strategic decision making, and the hospital's strategic focus. We surveyed top management team members of 72 nonacademic hospitals to explore the participation of critical stakeholder groups such as the board of directors in the strategic decision-making process. We used hierarchical regression analysis to explore our hypotheses that there is a relationship between both the nature and involvement of the board and the hospital's strategic orientation. Hospitals with broader expertise on their boards reported an external focus. For some of their externally-oriented goals, hospitals also reported that their boards were involved earlier in the stages of decision making. In light of the complex and dynamic environment of hospitals today, those charged with developing hospital boards should match the variety in the external issues that the hospital faces with more variety in board makeup. By developing a board with greater breadth of expertise, the hospital responds to its complex environment by absorbing that complexity, enabling a greater potential for sensemaking and learning. Rather than acting only as monitors and advisors, boards impact their hospitals' strategic focus through their participation in the strategic decision-making process.

Boarding Schools.

ERIC Educational Resources Information Center

Boarding Schools, Boston, MA.

This booklet has been prepared to provide students, parents, and counselors with information about America's boarding schools and to help them with the application process. It includes brief descriptions of 139 boarding schools--junior schools, boys' schools, girls' schools, military academies, and coeducational schools. It is offered solely as an…

EFFECT OF AN ACID RAIN ENVIRONMENT ON LIMESTONE SURFACES.

USGS Publications Warehouse

Mossotti, Victor G.; Lindsay, James R.; Hochella, Michael F.

1987-01-01

Salem limestone samples were exposed to weathering for 1 y in several urban and one rural environments. Samples exposed in the rural location were chemically indistinguishable from the freshly quarried limestone, whereas all samples collected from urban exposure sites developed gypsum stains on the ground-facing surfaces where the stones were not washed by precipitation. The gas-solid reaction of SO//2 with calcite was selected for detailed consideration. It appears from the model that under arid conditions, the quantity of stain deposited on an unwashed surface is independent of atmospheric SO//2 concentration once the surface has been saturated with gypsum. Under wet conditions, surface sulfation and weight loss are probably dominated by mechanisms involving wet stone. However, if the rain events are frequent and delimited by periods of dryness, the quantity of gypsum produced by a gas-solid reaction mechanism should correlate with both the frequency of rain events and the atmospheric SO//2 level.

Refinement of boards' role required.

PubMed

Umbdenstock, R J

1987-01-01

The governing board's role in health care is not changing, but new competitive forces necessitate a refinement of the board's approach to fulfilling its role. In a free-standing, community, not-for-profit hospital, the board functions as though it were the "owner." Although it does not truly own the facility in the legal sense, the board does have legal, fiduciary, and financial responsibilities conferred on it by the state. In a religious-sponsored facility, the board fulfills these same obligations on behalf of the sponsoring institute, subject to the institute's reserved powers. In multi-institutional systems, the hospital board's power and authority depend on the role granted it by the system. Boards in all types of facilities are currently faced with the following challenges: Fulfilling their basic responsibilities, such as legal requirements, financial duties, and obligations for the quality of care. Encouraging management and the board itself to "think strategically" in attacking new competitive market forces while protecting the organization's traditional mission and values. Assessing recommended strategies in light of consequences if constituencies think the organization is abandoning its commitments. Boards can take several steps to match their mode of operation with the challenges of the new environment. Boards must rededicate themselves to the hospital's mission. Trustees must expand their understanding of health care trends and issues and their effect on the organization. Boards must evaluate and help strengthen management's performance, rather than acting as a "watchdog" in an adversarial position. Boards must think strategically, rather than focusing solely on operational details. Boards must evaluate the methods they use for conducting business.

Technical Review Board Chairperson Guidelines for Conducting Technical Review Boards for Rocket Testing

DTIC Science & Technology

2011-08-17

to create a guide for technical review board chairperson conducting technical review boards for rocket testing performed by the Air Force Research ...BOARDS FOR ROCKET TESTING   TABLE OF CONTENTS List of Acronyms 1 Abstract 2 Chapter 1. Introduction 3 Introduction and Research Question 3...boards for rocket testing performed by the Air Force Research Laboratory’s Space Missile Propulsion Division located at Edwards Air Force Base in

CHARACTERIZATION AND REDUCTION OF FORMALDEHYDE EMISSIONS FROM A LOW-VOC LATEX PAINT

EPA Science Inventory

The patterns of formaldehyde emission from a low volatile organic compound (VOC) latex paint applied to gypsum board were measured and analyzed by small environmental chamber tests. It was found that the formaldehyde emissions resulted in sharp increase of chamber air formaldehy...

Large public display boards: a case study of an OR board and design implications.

PubMed

Lasome, C E; Xiao, Y

2001-01-01

A compelling reason for studying artifacts in collaborative work is to inform design. We present a case study of a public display board (12 ft by 4 ft) in a Level-I trauma center operating room (OR) unit. The board has evolved into a sophisticated coordination tool for clinicians and supporting personnel. This paper draws on study findings about how the OR board is used and organizes the findings into three areas: (1) visual and physical properties of the board that are exploited for collaboration, (2) purposes the board was configured to serve, and (3) types of physical and perceptual interaction with the board. Findings and implications related to layout, size, flexibility, task management, problem-solving, resourcing, shared awareness, and communication are discussed in an effort to propose guidelines to facilitate the design of electronic, computer driven display boards in the OR environment.

A Whole-Genome Microarray Study of Arabidopsis thaliana Semisolid Callus Cultures Exposed to Microgravity and Nonmicrogravity Related Spaceflight Conditions for 5 Days on Board of Shenzhou 8

PubMed Central

Neef, Maren; Ecke, Margret; Hampp, Rüdiger

2015-01-01

The Simbox mission was the first joint space project between Germany and China in November 2011. Eleven-day-old Arabidopsis thaliana wild type semisolid callus cultures were integrated into fully automated plant cultivation containers and exposed to spaceflight conditions within the Simbox hardware on board of the spacecraft Shenzhou 8. The related ground experiment was conducted under similar conditions. The use of an in-flight centrifuge provided a 1 g gravitational field in space. The cells were metabolically quenched after 5 days via RNAlater injection. The impact on the Arabidopsis transcriptome was investigated by means of whole-genome gene expression analysis. The results show a major impact of nonmicrogravity related spaceflight conditions. Genes that were significantly altered in transcript abundance are mainly involved in protein phosphorylation and MAPK cascade-related signaling processes, as well as in the cellular defense and stress responses. In contrast to short-term effects of microgravity (seconds, minutes), this mission identified only minor changes after 5 days of microgravity. These concerned genes coding for proteins involved in the plastid-associated translation machinery, mitochondrial electron transport, and energy production. PMID:25654111

What makes great boards great.

PubMed

Sonnenfeld, Jeffrey A

2002-09-01

In the wake of meltdowns at WorldCom, Tyco, and Enron, enormous attention has been focused on the companies' boards. It seems inconceivable that business disasters of such magnitude could happen without gross or even criminal negligence on the part of board members. And yet a close examination of those boards reveals no broad pattern of incompetence or corruption. In fact, they followed most of the accepted standards for board operations: Members showed up for meetings; they had money invested in the company; audit committees, compensation committees, and codes of ethics were in place; the boards weren't too small or too big, nor were they dominated by insiders. In other words, they passed the tests that would normally be applied to determine whether a board of directors was likely to do a good job. And that's precisely what's so scary, according to corporate governance expert Jeffrey Sonnenfeld, who suggests that it's time for some new thinking about how corporate boards operate and are evaluated. He proposes thinking not only about how to structure the board's work but also about how to manage it as a social system. Good boards are, very simply, high-functioning work groups. They're distinguished by a climate of respect, trust, and candor among board members and between the board and management. Information is shared openly and on time; emergent political factions are quickly eliminated. Members feel free to challenge one another's assumptions and conclusions, and management encourages lively discussion of strategic issues. Directors feel a responsibility to contribute meaningfully to the board's performance. In addition, good boards assess their own performance, both collectively and individually.

77 FR 55837 - Board Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

... FARM CREDIT SYSTEM INSURANCE CORPORATION Board Meeting AGENCY: Farm Credit System Insurance Corporation. ACTION: Regular meeting. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). Date and Time: The meeting of the Board will be held...

49 CFR 1011.2 - The Board.

Code of Federal Regulations, 2010 CFR

2010-10-01

... TRANSPORTATION GENERAL RULES AND REGULATIONS BOARD ORGANIZATION; DELEGATIONS OF AUTHORITY § 1011.2 The Board. (a... submitted for decision except those assigned to an individual Board Member or employee or an employee board...) The Board may bring before it any matter assigned to an individual Board Member or employee or...

76 FR 52997 - Public Company Accounting Oversight Board; Order Approving Proposed Board Funding Final Rules for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-24

... Accounting Oversight Board; Order Approving Proposed Board Funding Final Rules for Allocation of the Board's Accounting Support Fee Among Issuers, Brokers, and Dealers, and Other Amendments to the Board's Funding Rules August 18, 2011. I. Introduction On June 21, 2011, the Public Company Accounting Oversight Board (the...

7 CFR 984.6 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 8 2010-01-01 2010-01-01 false Board. 984.6 Section 984.6 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... Handling Definitions § 984.6 Board. Board means the California Walnut Board established pursuant to § 934...

7 CFR 984.6 - Board.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 8 2011-01-01 2011-01-01 false Board. 984.6 Section 984.6 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... Handling Definitions § 984.6 Board. Board means the California Walnut Board established pursuant to § 934...

32 CFR 865.4 - Board actions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Board actions. 865.4 Section 865.4 National... PERSONNEL REVIEW BOARDS Air Force Board for Correction of Military Records § 865.4 Board actions. (a) Board... serves as its chair. The panel's actions and decisions constitute the actions and decisions of the Board...

78 FR 4847 - Board Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-23

... FARM CREDIT SYSTEM INSURANCE CORPORATION Board Meeting AGENCY: Farm Credit System Insurance Corporation. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). DATE AND TIME: The meeting of the Board will be held at the offices of the Farm...

The diagnostic X-ray protection characteristics of Panelcrete, Aquapanel, Betopan and Gypsoplak Superboard.

PubMed

Tsalafoutas, I A; Yakoumakis, E; Sandilos, P; Vlahos, L; Proukakis, C

2001-04-01

Panelcrete, Aquapanel and Betopan are cement-based building materials with uses similar to those of gypsum wallboard, whose properties as a diagnostic X-ray shielding material have been extensively studied. The X-ray attenuation characteristics of these cement-based boards as well as those of a gypsum wallboard, Gypsoplak Superboard, are investigated for broad beam geometry conditions and for tube potentials of 50 kVp, 70 kVp, 100 kVp, 125 kVp and 140 kVp. Comparisons between these materials as well as with published data for gypsum wallboard are made. An example of their use as secondary barriers is given. Furthermore, it is confirmed that when building materials are considered for diagnostic X-ray shielding, calculations based on data for similar materials and corrected for density differences can be used only as an approximation.

Board Certification in Counseling Psychology

ERIC Educational Resources Information Center

Crowley, Susan L.; Lichtenberg, James W.; Pollard, Jeffrey W.

2012-01-01

Although specialty board certification by the American Board of Professional Psychology (ABPP) has been a valued standard for decades, the vast majority of counseling psychologists do not pursue board certification in the specialty. The present article provides a brief history of board certification in general and some historical information about…

East Europe Report, Economic and Industrial Affairs, Long-Term Program for Production Quality

DTIC Science & Technology

1984-05-29

increase the production of confectionery goods and snacks with a lower sugar content but enriched with natural juice and vegetable fillers, vegetable and...variety of con- struction materials and items by organizing the production of gasconcrete, extruded asbestos cement walls, gypsum board, heat, water

Environmental and Sustainable Technology Evaluations (ESTE): Verification of Microbial Resistant Building Materials

EPA Science Inventory

This is an ESTE project summary brief. Many of the finished interior surfaces of homes and buildings are composed of materials that are prone to mold growth. These surfaces include gypsum board, wood flooring, insulation, and components of the heating and air conditioning system...

Effect of disinfection on irreversible hydrocolloid and alternative impression materials and the resultant gypsum casts.

PubMed

Suprono, Montry S; Kattadiyil, Mathew T; Goodacre, Charles J; Winer, Myron S

2012-10-01

Many new products have been introduced and marketed as alternatives to traditional irreversible hydrocolloid materials. These alternative materials have the same structural formula as addition reaction silicone, also known as vinyl polysiloxane (VPS), impression materials. Currently, there is limited in vitro and in vivo research on these products, including on the effects of chemical disinfectants on the materials. The purpose of this study was to compare the effects of a spray disinfecting technique on a traditional irreversible hydrocolloid and 3 new alternative impression materials in vitro. The tests were performed in accordance with the American National Standards Institute/American Dental Association (ANSI/ADA) Specification Nos. 18 and 19. Under standardized conditions, 100 impressions were made of a ruled test block with an irreversible hydrocolloid and 3 alternative impression materials. Nondisinfected irreversible hydrocolloid was used as the control. The impressions were examined for surface detail reproduction before and after disinfection with a chloramine-T product. Type III and Type V dental stone casts were evaluated for linear dimensional change and gypsum compatibility. Comparisons of linear dimensional change were analyzed with 2-way ANOVA of mean ranks with the Scheffé post hoc comparisons (α=.05). Data for surface detail reproduction were analyzed with the Wilcoxon Signed-Rank procedure and gypsum compatibility with the Kruskal-Wallis Rank procedure (α=.05). The alternative impression materials demonstrated significantly better outcomes with all 3 parameters tested. Disinfection with chloroamine-T did not have any effect on the 3 alternative impression materials. The irreversible hydrocolloid groups produced the most variability in the measurements of linear dimensional change. All of the tested materials were within the ADA's acceptable limit of 1.0% for linear dimensional change, except for the disinfected irreversible hydrocolloid

Microbial characterization of microbial ecosystems associated to evaporites domes of gypsum in Salar de Llamara in Atacama desert.

PubMed

Rasuk, Maria Cecilia; Kurth, Daniel; Flores, Maria Regina; Contreras, Manuel; Novoa, Fernando; Poire, Daniel; Farias, Maria Eugenia

2014-10-01

The Central Andes in northern Chile contains a large number of closed basins whose central depression is occupied by saline lakes and salt crusts (salars). One of these basins is Salar de Llamara (850 m a.s.l.), where large domed structures of seemingly evaporitic origin forming domes can be found. In this work, we performed a detailed microbial characterization of these domes. Mineralogical studies revealed gypsum (CaSO(4)) as a major component. Microbial communities associated to these structures were analysed by 454 16S rDNA amplicon sequencing and compared between winter and summer seasons. Bacteroidetes Proteobacteria and Planctomycetes remained as the main phylogenetic groups, an increased diversity was found in winter. Comparison of the upper air-exposed part and the lower water-submerged part of the domes in both seasons showed little variation in the upper zone, showing a predominance of Chromatiales (Gammaproteobacteria), Rhodospirillales (Alphaproteobacteria), and Sphingobacteriales (Bacteroidetes). However, the submerged part showed marked differences between seasons, being dominated by Proteobacteria (Alpha and Gamma) and Verrucomicrobia in summer, but with more diverse phyla found in winter. Even though not abundant by sequence, Cyanobacteria were visually identified by scanning electron microscopy (SEM), which also revealed the presence of diatoms. Photosynthetic pigments were detected by high-performance liquid chromatography, being more diverse on the upper photosynthetic layer. Finally, the system was compared with other endoevaporite, mats microbialite and Stromatolites microbial ecosystems, showing higher similitude with evaporitic ecosystems from Atacama and Guerrero Negro. This environment is of special interest for extremophile studies because microbial life develops associated to minerals in the driest desert all over the world. Nevertheless, it is endangered by mining activity associated to copper and lithium extraction; thus, its

School Board Study Programs: Board Member's Manual Series 1.

ERIC Educational Resources Information Center

Brent, Daniel; Jurkowitz, Carolyn

This document provides eight lessons intended to improve the functioning of school boards and education committees for Catholic schools. Each lesson consists of three parts: a reading or activity to be done by the members in preparation for the lesson, a study activity to be done at the board meeting, and a reading or exercise to be done after the…

Effect of airborne particle on SO 2-calcite reaction

NASA Astrophysics Data System (ADS)

Böke, Hasan; Göktürk, E. Hale; Caner-Saltık, Emine N.; Demirci, Şahinde

1999-02-01

In modern urban atmosphere, sulphur dioxide (SO 2) attacks calcite (CaCO 3) in calcareous stone-producing gypsum (CaSO 4·2H 2O) which forms crust at rain sheltered surfaces and accelerates erosion at areas exposed to rain. The airborne particles collected on stone surfaces have always been considered to enhance the gypsum crust formation and thus it is believed that they should be removed from the surface to decrease the effects of SO 2. In this study, our aim was to investigate this event by carrying out a series of experiments in laboratory using pure calcium carbonate powder to represent calcareous stone. Sodium montmorillonite, activated carbon, ferric oxide, vanadium pentoxide and cupric chloride were mixed in the pure calcium carbonate powder as substitutes of the airborne particles in the polluted atmosphere. The samples have been exposed at nearly 10 ppmv SO 2 concentrations at 90% relative humidity conditions in a reaction chamber for several days. The mineralogical composition of the exposed samples were determined by X-ray diffraction (XRD) analysis and infrared spectrometer (IR). Sulphation reaction products, calcium sulphite hemihydrate, gypsum and unreacted calcite, were determined quantitatively using IR. Exposed samples have also been investigated morphologically using a scanning electron microscope (SEM). Experimental results reveal that calcium sulphite hemihydrate is the main reaction product of the SO 2-calcite reaction. It turns out that airborne particles play an important catalytic role in the oxidation of calcium sulphite hemihydrate into gypsum, although their presence does not very significantly affect the extent of sulphation reaction. This behaviour of airborne particles is explained by the presence of liquid film on the calcium carbonate surface where a series of reactions in the gas-liquid-solid interfaces takes place.

Board-to-Board Free-Space Optical Interconnections Passing through Boards for a Bookshelf-Assembled Terabit-Per-Second-Class ATM Switch.

PubMed

Hirabayashi, K; Yamamoto, T; Matsuo, S; Hino, S

1998-05-10

We propose free-space optical interconnections for a bookshelf-assembled terabit-per-second-class ATM switch. Thousands of arrayed optical beams, each having a rate of a few gigabits per second, propagate vertically to printed circuit boards, passing through some boards, and are connected to arbitrary transmitters and receivers on boards by polarization controllers and prism arrays. We describe a preliminary experiment using a 1-mm-pitch 2 x 2 beam-collimator array that uses vertical-cavity surface-emitting laser diodes. These optical interconnections can be made quite stable in terms of mechanical shock and temperature fluctuation by the attachment of reinforcing frames to the boards and use of an autoalignment system.

Effective School Board Governance Behaviors of Montana School Board Members: A Delphi Study

ERIC Educational Resources Information Center

Rocksund, Jill Ann

2017-01-01

School board governance matters. Past research has demonstrated that effective school boards are associated with higher student achievement. However, this research has been less clear about what those agreed upon effective practices are. The current study set out to identify effective school board governance practices and to determine the extent…

Why Boards Go Bad

ERIC Educational Resources Information Center

Chait, Richard P.

2006-01-01

This article addresses the problem of inept, ineffective, and mediocre governing boards at America's colleges and universities. It maintains that substandard governance can almost always be traced to one of two culprits, or both: (1) most boards are orchestras of soloists; and (2) many boards tend to either lionize or trivialize the president.…

First AGU Board of Directors

NASA Astrophysics Data System (ADS)

McPhaden, Michael J.

2010-08-01

On 1 July 2010, the first AGU Board of Directors took office. The board is composed of the president, president-elect, immediate past president, general secretary, international secretary, development board chair, six members elected by the Union membership, vice chair of the AGU Council, and the executive director. Two additional members may be nominated by the AGU president and approved by the board. The creation of the board is a result of the new governance structure approved by the AGU membership in November 2009. The board is responsible for the business aspects of the Union, while an expanded AGU Council will focus on science issues. Council members will be introduced in a future issue of Eos.

Evaluation of Electrochemical Migration on Printed Circuit Boards with Lead-Free and Tin-Lead Solder

NASA Astrophysics Data System (ADS)

He, Xiaofei; Azarian, Michael H.; Pecht, Michael G.

2011-09-01

To evaluate the current leakage and electrochemical migration behavior on printed circuit boards with eutectic tin-lead and lead-free solder, IPC B-24 comb structures were exposed to 65°C and 88% relative humidity conditions under direct-current (DC) bias for over 1500 h. These boards were processed with either Sn-3.0Ag-0.5Cu solder or Sn-37Pb solder. In addition to solder alloy, board finish (organic solderability preservative versus lead-free hot air solder leveling), spacing (25 mil versus 12.5 mil), and voltage (40 V versus 5 V bias) were also assessed by using in situ measurements of surface insulation resistance (SIR) and energy-dispersive spectroscopy after testing. It was shown that an initial increase of SIR was caused by consumption of electroactive species on the surface, intermittent drops of SIR were caused by dendritic growth, and a long-term SIR decline was caused by electrodeposition of a metallic layer. The prolonged SIR decline of Sn-3.0Ag-0.5Cu boards was simulated by three-dimensional (3D) progressive and instantaneous nucleation models, whose predictions were compared with experimental data. Sn-37Pb boards exhibited comigration of Sn, Pb, and Cu, while Sn-3.0Ag-0.5Cu boards incurred comigration of Sn, Ag, and Cu. Among the migrated species, Sn always dominated and was observed as either a layer or in polyhedral deposits, Pb was the most common element found in the dendrites, Cu was a minor constituent, and Ag migrated only occasionally. Compared with solder alloy, board finishes played a secondary role in affecting SIR due to their complexation with or dissolution into the solder. The competing effect between electric field and spacing was also investigated.

School Boards: Emerging Governance Challenges

ERIC Educational Resources Information Center

Bradshaw, Patricia; Osborne, Rachel

2010-01-01

The governance role of school boards is not new. Local school boards have governed education in Canada since the 19th century. However, significant forces are impacting on school boards and how they enact their roles and responsibilities. In this article, the authors want to look at the growing pressures on school boards, to actively acknowledge…

EXPOSE-R on Mission on the ISS

NASA Astrophysics Data System (ADS)

Panitz, Corinna; Rabbow, Elke; Rettberg, Petra; Barczyk, Simon; Kloss, Maria; Reitz, Guenther

Currently EXPOSE-R is on mission! This astrobiological exposure facility was accommodated at the universal workplace URM-D Zenith payload site, located outside the Russian Svezda Module of the International Space Station (ISS) by extravehicular activity (EVA) on March 10th 2009. It contains 3 trays accommodating 12 sample compartments with sample carriers in three levels either open to space vacuum or kept in a defined gas environment. In its 8 experiments of biological and chemical content, more than 1200 individual samples are exposed to solar ultraviolet (UV) radiations, vacuum, cosmic rays or extreme temperature variations. In their different experiments the involved scientists are studying the question of life's origin on Earth and the results of their experiments are contributing to different aspects of the evolution and distribution of life in the Universe. Additionally integrated into the EXPOSE-R facility are several dosimeters monitoring the ionising and the solar UV-radiation during the mission to deliver useful information to complement the sample analysis. In close cooperation with the DLR and the Technical University Munich (TUM), the Rheinisch -Westfülische Technischen Hochschule Aachen (RWTH Aachen) operates the experiment "Spores". a This is one of the 6 astrobiological experiments of the ROSE-Consortium" (Response of Or-ganisms to Space Environment) of the EXPOSE-R mission. In these experiments spores of bacteria, fungi and ferns are being over layered or mixed with meteorite material. The analysis of the effect of the space parameters on different biological endpoints of the spores of the mi-croorganism Bacillus subtilis will be performed after the retrieval of the experiment scheduled for the end of 2010. Parallel to the space mission an identical set of samples was accommodated into EXPOSE-R trays identical in construction to perform the Mission Ground Reference (MGR) Test. Currently this MGR Test is carried out in the Planetary and Space

Alaska Board of Forestry

Science.gov Websites

Natural Resources / Division of Forestry Alaska Board of Forestry The nine-member Alaska Board of Forestry advises the state on forest practices issues and provides a forum for discussion and resolution of forest management issues on state land. The board also reviews all proposed changes to the Alaska Forest Resources

Hospital board effectiveness: relationships between governing board composition and hospital financial viability.

PubMed Central

Molinari, C; Morlock, L; Alexander, J; Lyles, C A

1993-01-01

OBJECTIVE. Two theories--agency and managerialism--are compared with respect to their usefulness in explaining the role of insiders on the hospital board: whether their participation enhances or impairs board financial decision making. DATA SOURCES/STUDY SETTING. The study used 1985 hospital financial and governing board data for a representative sample of acute care California hospitals. STUDY DESIGN. Relationships were examined cross-sectionally between the presence or absence of insiders on the board and measures of hospital financial viability while controlling for the organizational factors of system affiliation, ownership, size, region, and corporate restructuring. PRINCIPAL FINDINGS. Multiple regression analysis found significant relationships between insider (CEO, medical staff) participation and hospital viability. CONCLUSIONS. These results support the managerial theory of governance by suggesting that the CEO and medical staff provide informational advantages to the hospital governing board. However, the cross-sectional design points to the need for future longitudinal studies in order to sequence these relationships between insider participation and improved hospital viability. PMID:8344824

49 CFR 1011.5 - Employee boards.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 8 2010-10-01 2010-10-01 false Employee boards. 1011.5 Section 1011.5... OF TRANSPORTATION GENERAL RULES AND REGULATIONS BOARD ORGANIZATION; DELEGATIONS OF AUTHORITY § 1011.5 Employee boards. This section covers matters assigned to the Accounting Board, a board of employees of the...

The Role of the Foundation Board. Foundation Relations. Board Basics.

ERIC Educational Resources Information Center

Simic, Curtis R.

1998-01-01

This booklet for trustees of institutions of higher education addresses the role of boards of related non-profit fund-raising foundations. The booklet begins with an explanation of four advantages of such foundations to host institutions, such as separating gift funds from public funds. Suggestions for making foundation boards more effective…

7 CFR 981.22 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE ALMONDS GROWN IN CALIFORNIA Order Regulating Handling Definitions § 981.22 Board. Board means the Almond Board of California which is the administrative...

Survival of Salmonella on refrigerated chicken carcasses and subsequent transfer to cutting board.

PubMed

Jiménez, S M; Tiburzi, M C; Salsi, M S; Moguilevsky, M A; Pirovani, M E

2009-06-01

To determine the effect of refrigeration time and temperature on Salmonella cell numbers on inoculated chicken carcasses and their transfer to a plastic cutting board. The survival of Salmonella on chicken skin and the transfer to a plastic cutting board when exposed to different refrigeration temperatures (2, 6 or 8 degrees C) for 9 days were the two main issues on which this work focused. Two scenarios were carried out to ascertain these effects: carcasses treated with a decontaminating acetic acid solution and untreated carcasses. All of the contaminated carcasses remained contaminated after 9 days of refrigeration. However, on untreated samples, while Salmonella numbers increased almost 1.5 log at 8 degrees C, the pathogen numbers decreased about 1 log at 2 and 6 degrees C. On acid-treated samples, cell numbers slightly decreased at all of the temperatures studied. Temperature did not affect salmonellae transfer to the cutting board, but time did. Acid decontamination increased cell numbers transferred to the cutting board compared with untreated samples. Proper refrigeration at low temperatures did not allow Salmonella numbers to rise, regardless of which carcasses had been, or had not been, acid treated. Despite the fact that the rate of transfer was not affected by temperature, the acid treatment detached Salmonella cells from the chicken skin and, therefore, the probability of greater cross-contamination should be studied further. The results of this study may provide better information about the refrigeration conditions for fresh chicken storage and also determine if these, along with acetic acid decontamination of broiler chicken, would affect the pathogen transfer to a cutting board.

SUBSTRATE EFFECTS ON VOC EMISSIONS FROM A LATEX PAINT

EPA Science Inventory

The effects of two substrates -- a stainless steel plate and a gypsum board -- on the volatile organic compound (VOC) emissions from a latex paint were evaluated by environmental chamber tests. It was found that the amount of VOCs emitted from the painted stainless steel was 2 to...

The Board's Role in Fund-Raising. The Fundamentals. Board Basics.

ERIC Educational Resources Information Center

Legon, Richard D.

1997-01-01

Fund-raising is one of the college or university governing board's most basic and important responsibilities: The annual fund is the platform from which all other fund-raising activities flow, and the board plays a key role in planning, implementing, and monitoring comprehensive campaigns, which are major efforts, focused on long-range financial…

36 CFR 1151.5 - Board meetings.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Board meetings. 1151.5... BOARD BYLAWS § 1151.5 Board meetings. (a) Number. The Chair shall schedule five regular meetings of the.... Regular meetings of the Board and at least one Board sponsored event shall ordinarily be held on the...

Assessment of groundwater contamination by gypsum dissolution in San Luis Potosí (México) using geoelectrical characterization

NASA Astrophysics Data System (ADS)

Arango-Galvan, C.; Ramos-Leal, J. A.; Yáñez-Rodríguez, M. A.; Corbo-Camargo, F.

2017-12-01

The Cerritos and Río Verde aquifers in San Luis Potosí (central México) make up a very complex aquifer system that is seriously affected by the overexploitation and the high concentration of sulphates. Currently, it is partially closed for extraction causing a substantial decrease in per capita drinking water availability affecting to more than 50,000 inhabitants in the region. Therefore, a very comprehensive study has been proposed in order to evaluate not only the groundwater contamination distribution but also to better know the aquifer configuration and its main hydrogeological characteristics as well. These studies include a detailed geological reconnaissance, hydrogeochemical analyses and a geoelectrical characterization. The main goal is to assess the aquifer geometry and to identify the gypsum horizons causing the presence of higher concentrations of sulphates in drinking water. A total of 26 audiomagnetotelluric soundings were measured and modelled along profiles following a perpendicular direction to the NW regional trending. Two-dimensional resistivity models suggest the presence of a shallow conductive layer (C1) with resistivity values ranging from 10 to 20 Ohm.m. It is related to the upper aquifer with a very low exploitation potential. A less conductive horizon (C2; 50 Ohm.m) underlying the shallow aquifer could be related to a very fractured limestone horizon forming a confined aquifer in the middle of the valley. A very resistive layer (R1) is observed underlying C1 and C2 units. This strata shows higher resistivity values (>100 Ohm.m) and could be associated with a reefal limestone identified as El Abra Formation. Finally, a conductive layer (<100 Ohm.m) observed beneath this horizon could be related to the oldest stratigraphic unit outcropping on the region, the Guaxcamá Formation, a gypsum-enriched unit, that contributes to the presence of sulphates in the upper aquifers by dissolution processes.

WeaselBoard :

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

Mulder, John C.; Schwartz, Moses Daniel; Berg, Michael J.

2013-10-01

Critical infrastructures, such as electrical power plants and oil refineries, rely on programmable logic controllers (PLCs) to control essential processes. State of the art security cannot detect attacks on PLCs at the hardware or firmware level. This renders critical infrastructure control systems vulnerable to costly and dangerous attacks. WeaselBoard is a PLC backplane analysis system that connects directly to the PLC backplane to capture backplane communications between modules. WeaselBoard forwards inter-module traffic to an external analysis system that detects changes to process control settings, sensor values, module configuration information, firmware updates, and process control program (logic) updates. WeaselBoard provides zero-daymore » exploit detection for PLCs by detecting changes in the PLC and the process. This approach to PLC monitoring is protected under U.S. Patent Application 13/947,887.« less

77 FR 60146 - SES Performance Review Board

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-02

... NATIONAL TRANSPORTATION SAFETY BOARD SES Performance Review Board AGENCY: National Transportation... National Transportation Safety Board, Performance Review Board (PRB). FOR FURTHER INFORMATION CONTACT... Performance Review Boards. The board reviews and evaluates the initial appraisal of a senior executive's...

76 FR 70169 - SES Performance Review Board

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-10

... NATIONAL TRANSPORTATION SAFETY BOARD SES Performance Review Board AGENCY: National Transportation... National Transportation Safety Board, Performance Review Board (PRB). FOR FURTHER INFORMATION CONTACT... Performance Review Boards. The board reviews and evaluates the initial appraisal of a senior executive's...

Cosmic Radiation Exposure of Biological Test Systems During the EXPOSE-E Mission

PubMed Central

Hajek, Michael; Bilski, Pawel; Körner, Christine; Vanhavere, Filip; Reitz, Günther

2012-01-01

Abstract In the frame of the EXPOSE-E mission on the Columbus external payload facility EuTEF on board the International Space Station, passive thermoluminescence dosimeters were applied to measure the radiation exposure of biological samples. The detectors were located either as stacks next to biological specimens to determine the depth dose distribution or beneath the sample carriers to determine the dose levels for maximum shielding. The maximum mission dose measured in the upper layer of the depth dose part of the experiment amounted to 238±10 mGy, which relates to an average dose rate of 408±16 μGy/d. In these stacks of about 8 mm height, the dose decreased by 5–12% with depth. The maximum dose measured beneath the sample carriers was 215±16 mGy, which amounts to an average dose rate of 368±27 μGy/d. These values are close to those assessed for the interior of the Columbus module and demonstrate the high shielding of the biological experiments within the EXPOSE-E facility. Besides the shielding by the EXPOSE-E hardware itself, additional shielding was experienced by the external structures adjacent to EXPOSE-E, such as EuTEF and Columbus. This led to a dose gradient over the entire exposure area, from 215±16 mGy for the lowest to 121±6 mGy for maximum shielding. Hence, the doses perceived by the biological samples inside EXPOSE-E varied by 70% (from lowest to highest dose). As a consequence of the high shielding, the biological samples were predominantly exposed to galactic cosmic heavy ions, while electrons and a significant fraction of protons of the radiation belts and solar wind did not reach the samples. Key Words: Space radiation—Dosimetry—Passive radiation detectors—Thermoluminescence—EXPOSE-E. Astrobiology 12, 387–392. PMID:22680685

75 FR 69706 - SES Performance Review Board

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-15

... NATIONAL TRANSPORTATION SAFETY BOARD SES Performance Review Board AGENCY: National Transportation... National Transportation Safety Board Performance Review Board (PRB). FOR FURTHER INFORMATION CONTACT: Emily... Review Boards. The board reviews and evaluates the initial appraisal of a senior executive's performance...

Fungal Microbiomes Associated with Green and Non-Green Building Materials

PubMed Central

Coombs, Kanistha; Vesper, Stephen; Green, Brett J.; Yermakov, Mikhail; Reponen, Tiina

2018-01-01

Water-damaged buildings can lead to fungal growth and occupant health problems. Green building materials, derived from renewable sources, are increasingly utilized in construction and renovations. However, the question as to what fungi will grow on these green compared to non-green materials, after they get wet, has not been adequately studied. By determining what fungi grow on each type of material, the potential health risks can be more adequately assessed. In this study, we inoculated green and non-green pieces of ceiling tile, composite board, drywall, and flooring with indoor dust containing a complex mixture of naturally occurring fungi. The materials were saturated with water and incubated for two months in a controlled environment. The resulting fungal microbiomes were evaluated using ITS amplicon sequencing. Overall, the richness and diversity of the mycobiomes on each pair of green and non-green pieces were not significantly different. However, different genera dominated on each type of material. For example, Aspergillus spp. had the highest relative abundance on green and non-green ceiling tiles and green composite boards, but Peniophora spp. dominated the non-green composite board. In contrast, Penicillium spp. dominated green and non-green flooring samples. Green gypsum board was dominated by Phialophora spp. and Stachybotrys spp., but non-green gypsum board by Myrothecium spp. These data suggest that water-damaged green and non-green building materials can result in mycobiomes that are dominated by fungal genera whose member species pose different potentials for health risks. PMID:29681691

Fungal Microbiomes Associated with Green and Non-Green Building Materials.

PubMed

Coombs, Kanistha; Vesper, Stephen; Green, Brett J; Yermakov, Mikhail; Reponen, Tiina

2017-01-01

Water-damaged buildings can lead to fungal growth and occupant health problems. Green building materials, derived from renewable sources, are increasingly utilized in construction and renovations. However, the question as to what fungi will grow on these green compared to non-green materials, after they get wet, has not been adequately studied. By determining what fungi grow on each type of material, the potential health risks can be more adequately assessed. In this study, we inoculated green and non-green pieces of ceiling tile, composite board, drywall, and flooring with indoor dust containing a complex mixture of naturally occurring fungi. The materials were saturated with water and incubated for two months in a controlled environment. The resulting fungal microbiomes were evaluated using ITS amplicon sequencing. Overall, the richness and diversity of the mycobiomes on each pair of green and non-green pieces were not significantly different. However, different genera dominated on each type of material. For example, Aspergillus spp. had the highest relative abundance on green and non-green ceiling tiles and green composite boards, but Peniophora spp. dominated the non-green composite board. In contrast, Penicillium spp. dominated green and non-green flooring samples. Green gypsum board was dominated by Phialophora spp. and Stachybotrys spp., but non-green gypsum board by Myrothecium spp. These data suggest that water-damaged green and non-green building materials can result in mycobiomes that are dominated by fungal genera whose member species pose different potentials for health risks.

Development of an Experimental Board in the Nanaosatellite CUBESAT3

NASA Astrophysics Data System (ADS)

Cresciucci, Laetitia

first component studied is an analog to digital converter, the AD670. It has been choose by Alcatel because it is used on a satellite and doesn't work properly. Many tests have been performed to determine why this component fails, and CUBESAT is the experience which can prove if those ground results correspond to the results we will obtain during the flight. The two other components on the board are a mosfet transistor, the IRF450, and an optocoupler, the SFH610A. These devices have been studied in the CEM2 with a new space degradation prediction method called the Isochronal Annealing. With CUBESAT, the CEM2 wants to show that the results obtained with this method are reliable. In order to prove that the results match the predictions, we had to include a dosimeter, which measure the amount of radiation received and a temperature sensor. If this is a success, this method could be recognized by the aerospace industry. conception. After this prototype was done, we were asked to make a space qualified board, which included the study of the environment for CUBESAT's orbit (650 km, 65° inclination),as well as the thermal study in order to justify the choices of the components which measure the degradation of the 3 devices under test. Most parts had to undergo testing to prove their reliability when exposed to space radiations. The final payload board includes the different measurements' electronics and a microcontroller that controls the tests, collects the data and communicate with the platform. The last part of our work was to perform the integration of the payload board in the CUBESAT structure. This included solving mechanical problems and programming the communication interface between our board and the satellite's control board. We spent two weeks in Arizona working on this integration, in collaboration with the American students involved in this project. Now the payload design is complete, CUBESAT is ready to fly.

7 CFR 1215.2 - Board.

Code of Federal Regulations, 2013 CFR

2013-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information Order Definitions § 1215.2 Board. Board means the Popcorn Board established under section 575(b) of the Act. ...

7 CFR 1215.2 - Board.

Code of Federal Regulations, 2012 CFR

2012-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information Order Definitions § 1215.2 Board. Board means the Popcorn Board established under section 575(b) of the Act. ...

7 CFR 1215.2 - Board.

Code of Federal Regulations, 2014 CFR

2014-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information Order Definitions § 1215.2 Board. Board means the Popcorn Board established under section 575(b) of the Act. ...

7 CFR 1215.2 - Board.

Code of Federal Regulations, 2011 CFR

2011-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information Order Definitions § 1215.2 Board. Board means the Popcorn Board established under section 575(b) of the Act. ...

7 CFR 1215.2 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POPCORN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Popcorn Promotion, Research, and Consumer Information Order Definitions § 1215.2 Board. Board means the Popcorn Board established under section 575(b) of the Act. ...

7 CFR 1220.102 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Soybean Promotion and Research Order Definitions § 1220.102 Board. The term Board means the United Soybean Board established under § 1220.201 of this subpart. ...

7 CFR 1220.102 - Board.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN PROMOTION, RESEARCH, AND CONSUMER INFORMATION Soybean Promotion and Research Order Definitions § 1220.102 Board. The term Board means the United Soybean Board established under § 1220.201 of this subpart. ...

7 CFR 1280.102 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE LAMB PROMOTION, RESEARCH, AND INFORMATION ORDER Lamb Promotion, Research, and Information Order Definitions § 1280.102 Board. Board means the Lamb Promotion, Research, and Information Board established pursuant to § 1280.201. ...

Moving Large Wiring-Harness Boards

NASA Technical Reports Server (NTRS)

Shepherd, Samuel D.; Gurman, Isaac

1990-01-01

Carrier for wiring-harness fabrication boards enables lone operator to move board easily and safely. Holds harness while operator fabricating, while being stored, and being transported to equipment frame for mounting. When positioned for assembly of wiring harness, board and carrier give operator easy and convenient access to wires and cables, when positioned for transfer of wiring harness to or from storage area, carrier holds board securely while moved by one person.

A New Stratified Sampling Procedure which Decreases Error Estimation of Varroa Mite Number on Sticky Boards.

PubMed

Kretzschmar, A; Durand, E; Maisonnasse, A; Vallon, J; Le Conte, Y

2015-06-01

A new procedure of stratified sampling is proposed in order to establish an accurate estimation of Varroa destructor populations on sticky bottom boards of the hive. It is based on the spatial sampling theory that recommends using regular grid stratification in the case of spatially structured process. The distribution of varroa mites on sticky board being observed as spatially structured, we designed a sampling scheme based on a regular grid with circles centered on each grid element. This new procedure is then compared with a former method using partially random sampling. Relative error improvements are exposed on the basis of a large sample of simulated sticky boards (n=20,000) which provides a complete range of spatial structures, from a random structure to a highly frame driven structure. The improvement of varroa mite number estimation is then measured by the percentage of counts with an error greater than a given level. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

7 CFR 1216.4 - Board.

Code of Federal Regulations, 2011 CFR

2011-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.4 Board. Board means the administrative body referred to as the National Peanut Board established pursuant to § 1216.40. ...

7 CFR 1216.4 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.4 Board. Board means the administrative body referred to as the National Peanut Board established pursuant to § 1216.40. ...

NPS Transit System Passenger Boardings Study: Converting Ticket Sales to Passenger Boardings.

DOT National Transportation Integrated Search

2016-01-01

This report examines the reporting of passenger boardings (unlinked passenger trips) by NPS transit systems that use a ticket sales conversion methodology. By studying and validating the park units' passenger boarding methodology from converting tick...

7 CFR 1214.2 - Board.

Code of Federal Regulations, 2013 CFR

2013-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.2 Board. Board or the Christmas Tree Promotion Board means the administrative body established pursuant to § 1214.40. ...

7 CFR 1214.2 - Board.

Code of Federal Regulations, 2012 CFR

2012-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.2 Board. Board or the Christmas Tree Promotion Board means the administrative body established pursuant to § 1214.40. ...

7 CFR 1214.2 - Board.

Code of Federal Regulations, 2014 CFR

2014-01-01

... ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.2 Board. Board or the Christmas Tree Promotion Board means the administrative body established pursuant to § 1214.40. ...

Deposition velocities and impact of physical properties on ozone removal for building materials

NASA Astrophysics Data System (ADS)

Lin, Chi-Chi; Hsu, Shu-Chen

2015-01-01

This study aims to estimate the ozone deposition velocities of eight commonly used building materials (BMs) which include calcium silicate board (CSB), green calcium silicate board (GCSB), mineral fiber ceiling (MFC), green mineral fiber ceiling (GMFC), gypsum board (GB), green gypsum board (GGB), wooden flooring (WF) and green wooden flooring (GWF). In addition, the impact of physical properties (specific surface area and total pore volume of BM) on ozone removal ability was also explored and discussed. Studies were conducted in a small-scale environmental stainless steel chamber. CSB and GCSB showed the highest ozone deposition velocities, while WF and GWF showed the lowest ozone deposition velocities among test BMs materials. All reaction probabilities were estimated to fall within the order of magnitude of 10-6. Green BMs showed lower reaction probabilities with ozone comparing with non-green BMs except for GGB. Consistent with the trends for deposition velocity, fleecy and porous materials exhibit higher reaction probabilities than smooth, non-porous surfaces. Specific surface area of BM is more closely related to ozone removal than total pore volume of BM with R2 of 0.93 vs. R2 of 0.84. Discussion of Thiele modulus for all test BMs indicates surface reactions are occurring quickly relative to internal diffusion and ozone removal is internal diffusion-limited.

Physical properties of salt, anhydrite and gypsum : preliminary report

USGS Publications Warehouse

Robertson, Eugene C.; Robie, Richard A.; Books, Kenneth G.

1958-01-01

This summary is the result of a search of the available literature. Emphasis is placed on the mechanical and calorimetric properties of salt; the measurements of elastic, thermal, magnetic, and mass properties of salt are merely tabulated. Under hydrostatic pressure 100 percent at a nearly constant stress difference of about 300 kg/cm2. Similarily, under temperatures > 400?C at one atmosphere, salt deforms plastically to strains > 100 percent under stress differences of about 100 kg/cm2. Entha1pies were calculated for various temperatures to 2,000? C from the low temperature and high temperature heat capacities and the heats of solution of the following minerals: salt (or halite), NaCl; anhydrite, CaS04; quartz, Si02; and calcite, CaC03. Three combinations of these minerals were assumed to represent three possible natural salt beds, and the heats required to raise the temperature of each to 1,500?C and to 2,000?C were calculated. For a half and half mixture of salt and anhydrite, 1,300 cal/gm were required to raise the temperature to 2,000?C. For an evaporite containing 60 percent salt and about equal amounts of anhydrite, calcite, and quartz, 1,100 cal/gm are required to raise the temperature to 2,OOO?C. Most of the measurements of the elastic moduli were made on single crystals of salt, anhydrite, and gypsum. For the most part, the measurements of density, magnetic susceptibility, and other properties were made on natural salt samples.

77 FR 39677 - Performance Review Board Membership

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-05

... ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD Performance Review Board Membership AGENCY: Architectural and Transportation Barriers Compliance Board. ACTION: Notice. SUMMARY: Notice is... Transportation Barriers Compliance Board (Access Board). FOR FURTHER INFORMATION CONTACT: David M. Capozzi...

SMART Boards Rock

ERIC Educational Resources Information Center

Giles, Rebecca M.; Shaw, Edward L.

2011-01-01

SMART Board is a technology that combines the functionality of a whiteboard, computer, and projector into a single system. The interactive nature of the SMART Board offers many practical uses for providing an introduction to or review of material, while the large work area invites collaboration through social interaction and communication. As a…

7 CFR 1210.304 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Board. 1210.304 Section 1210.304 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... PLAN Watermelon Research and Promotion Plan Definitions § 1210.304 Board. Board means the National...

77 FR 1956 - National Science Board; Notice of Opportunity for Public Comment on the National Science Board...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-12

... NATIONAL SCIENCE FOUNDATION National Science Board; Notice of Opportunity for Public Comment on the National Science Board Data Policies Report AGENCY: National Science Board (NSB), NSF. ACTION: Request for public comments. SUMMARY: The National Science Board seeks comments from the public on the...

Printed wiring board system programmer's manual

NASA Technical Reports Server (NTRS)

Brinkerhoff, C. D.

1973-01-01

The printed wiring board system provides automated techniques for the design of printed circuit boards and hybrid circuit boards. The system consists of four programs: (1) the preprocessor program combines user supplied data and pre-defined library data to produce the detailed circuit description data; (2) the placement program assigns circuit components to specific areas of the board in a manner that optimizes the total interconnection length of the circuit; (3) the organizer program assigns pin interconnections to specific board levels and determines the optimal order in which the router program should attempt to layout the paths connecting the pins; and (4) the router program determines the wire paths which are to be used to connect each input pin pair on the circuit board. This document is intended to serve as a programmer's reference manual for the printed wiring board system. A detailed description of the internal logic and flow of the printed wiring board programs is included.

DOE's Environmental Management Site-Specific Advisory Board: The Roles, Work, and Assessment of the Constituent Local Boards - 13587

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

Alexander, Catherine; Freeman, Jenny; Cantrell, Yvette

2013-07-01

The charter for the Department of Energy's Environmental Management (EM) Site-Specific Advisory Board (SSAB) was approved under the Federal Advisory Committee Act (FACA) in 1994. With a unique mandate to provide public input on issues associated with the cleanup of nuclear legacy sites in the U.S., the EM SSAB comprises eight local boards, which are based at major EM sites. While each board is unique to the community in which it is located and reflects the diversity of the local population, the boards are governed by FACA, related regulations, and DOE policies that are intended to standardize agency advisory boardmore » operations. The EM SSAB local boards are made up of a diverse group of citizens who want to understand the mission and goals of the EM program and to help EM achieve those goals for the benefit of their communities. Some are quite passionate about their mission; others need to be coaxed into active participation. Maintaining productive relationships and a supportive environment for effective board operations is the challenge of board management for DOE EM and the board members themselves. DOE draws on research findings and best practices literature from academics and practitioners in the field of public involvement in its board management practices. The EM SSAB is also evaluated annually under the law to ensure that the investment of taxpayer dollars in the board is warranted in light of the contributions of the board. Further evaluation takes place at the agency and site levels in order to identify what aspects of board functioning the agency and board members find important to its success and to address areas where improvement is needed. Board contributions, compliance factors, and measurable outcomes related to board products and process areas are key to agency commitment to ongoing support of the boards and to participant satisfaction and thus continued member involvement. In addition to evaluation of these factors in improving board

Sorption and reemission of formaldehyde by gypsum wallboard. Report for June 1990-August 1992

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

Chang, J.C.S.

1993-01-01

The paper gives results of an analysis of the sorption and desorption of formaldehyde by unpainted wallboard, using a mass transfer model based on the Langmuir sorption isotherm. The sorption and desorption rate constants are determined by short-term experimental data. Long-term sorption and desorption curves are developed by the mass transfer model without any adjustable parameters. Compared with other empirically developed models, the mass transfer model has more extensive applicability and provides an elucidation of the sorption and desorption mechanism that empirical models cannot. The mass transfer model is also more feasible and accurate than empirical models for applications suchmore » as scale-up and exposure assessment. For a typical indoor environment, the model predicts that gypsum wallboard is a much stronger sink for formaldehyde than for other indoor air pollutants such as tetrachloroethylene and ethylbenzene. The strong sink effects are reflected by the high equilibrium capacity and slow decay of the desorption curve.« less

Investigation on mercury reemission from limestone-gypsum wet flue gas desulfurization slurry.

PubMed

Chen, Chuanmin; Liu, Songtao; Gao, Yang; Liu, Yongchao

2014-01-01

Secondary atmospheric pollutions may result from wet flue gas desulfurization (WFGD) systems caused by the reduction of Hg(2+) to Hg(0) and lead to a damping of the cobenefit mercury removal efficiency by WFGD systems. The experiment on Hg(0) reemission from limestone-gypsum WFGD slurry was carried out by changing the operating conditions such as the pH, temperature, Cl(-) concentrations, and oxygen concentrations. The partitioning behavior of mercury in the solid and liquid byproducts was also discussed. The experimental results indicated that the Hg(0) reemission rate from WFGD slurry increased as the operational temperatures and pH values increased. The Hg(0) reemission rates decreased as the O2 concentration of flue gas and Cl(-) concentration of WFGD slurry increased. The concentrations of O2 in flue gas have an evident effect on the mercury retention in the solid byproducts. The temperature and Cl(-) concentration have a slight effect on the mercury partitioning in the byproducts. No evident relation was found between mercury retention in the solid byproducts and the pH. The present findings could be valuable for industrial application of characterizing and optimizing mercury control in wet FGD systems.

Investigation on Mercury Reemission from Limestone-Gypsum Wet Flue Gas Desulfurization Slurry

PubMed Central

Liu, Songtao; Liu, Yongchao

2014-01-01

Secondary atmospheric pollutions may result from wet flue gas desulfurization (WFGD) systems caused by the reduction of Hg2+ to Hg0 and lead to a damping of the cobenefit mercury removal efficiency by WFGD systems. The experiment on Hg0 reemission from limestone-gypsum WFGD slurry was carried out by changing the operating conditions such as the pH, temperature, Cl− concentrations, and oxygen concentrations. The partitioning behavior of mercury in the solid and liquid byproducts was also discussed. The experimental results indicated that the Hg0 reemission rate from WFGD slurry increased as the operational temperatures and pH values increased. The Hg0 reemission rates decreased as the O2 concentration of flue gas and Cl− concentration of WFGD slurry increased. The concentrations of O2 in flue gas have an evident effect on the mercury retention in the solid byproducts. The temperature and Cl− concentration have a slight effect on the mercury partitioning in the byproducts. No evident relation was found between mercury retention in the solid byproducts and the pH. The present findings could be valuable for industrial application of characterizing and optimizing mercury control in wet FGD systems. PMID:24737981

Noise and sleep on board vessels in the Royal Norwegian Navy

PubMed Central

Sunde, Erlend; Bråtveit, Magne; Pallesen, Ståle; Moen, Bente Elisabeth

2016-01-01

Previous research indicates that exposure to noise during sleep can cause sleep disturbance. Seamen on board vessels are frequently exposed to noise also during sleep periods, and studies have reported sleep disturbance in this occupational group. However, studies of noise and sleep in maritime settings are few. This study's aim was to examine the associations between noise exposure during sleep, and sleep variables derived from actigraphy among seamen on board vessels in the Royal Norwegian Navy (RNoN). Data were collected on board 21 RNoN vessels, where navy seamen participated by wearing an actiwatch (actigraph), and by completing a questionnaire comprising information on gender, age, coffee drinking, nicotine use, use of medication, and workload. Noise dose meters were used to assess noise exposure inside the seamen's cabin during sleep. Eighty-three sleep periods from 68 seamen were included in the statistical analysis. Linear mixed-effects models were used to examine the association between noise exposure and the sleep variables percentage mobility during sleep and sleep efficiency, respectively. Noise exposure variables, coffee drinking status, nicotine use status, and sleeping hours explained 24.9% of the total variance in percentage mobility during sleep, and noise exposure variables explained 12.0% of the total variance in sleep efficiency. Equivalent noise level and number of noise events per hour were both associated with increased percentage mobility during sleep, and the number of noise events was associated with decreased sleep efficiency. PMID:26960785

22 CFR 908.3 - Board recommendations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Board recommendations. 908.3 Section 908.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD REMEDIES § 908.3 Board recommendations. (a) If the Board... disciplinary action against any employee of an Agency, it shall make an appropriate recommendation to the head...

22 CFR 908.3 - Board recommendations.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Board recommendations. 908.3 Section 908.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD REMEDIES § 908.3 Board recommendations. (a) If the Board... disciplinary action against any employee of an Agency, it shall make an appropriate recommendation to the head...

22 CFR 909.3 - Board recommendation.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Board recommendation. 909.3 Section 909.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD DECISIONMAKING § 909.3 Board recommendation. Where the Board's decision is a recommendation, it shall be directed to the head of the Agency. A copy of the...

22 CFR 909.3 - Board recommendation.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Board recommendation. 909.3 Section 909.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD DECISIONMAKING § 909.3 Board recommendation. Where the Board's decision is a recommendation, it shall be directed to the head of the Agency. A copy of the...

22 CFR 401.28 - Advisory boards.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Advisory boards. 401.28 Section 401.28 Foreign Relations INTERNATIONAL JOINT COMMISSION, UNITED STATES AND CANADA RULES OF PROCEDURE References § 401.28 Advisory boards. (a) The Commission may appoint a board or boards, composed of qualified persons, to...

22 CFR 902.3 - Board staff.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 22 Foreign Relations 2 2011-04-01 2009-04-01 true Board staff. 902.3 Section 902.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD ORGANIZATION § 902.3 Board staff. The chairperson shall select the Board's executive secretary and other staff provided for in the Act. The executive secretary and staff...

22 CFR 902.3 - Board staff.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 22 Foreign Relations 2 2010-04-01 2010-04-01 true Board staff. 902.3 Section 902.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD ORGANIZATION § 902.3 Board staff. The chairperson shall select the Board's executive secretary and other staff provided for in the Act. The executive secretary and staff...

22 CFR 902.3 - Board staff.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 22 Foreign Relations 2 2013-04-01 2009-04-01 true Board staff. 902.3 Section 902.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD ORGANIZATION § 902.3 Board staff. The chairperson shall select the Board's executive secretary and other staff provided for in the Act. The executive secretary and staff...

22 CFR 902.3 - Board staff.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 22 Foreign Relations 2 2012-04-01 2009-04-01 true Board staff. 902.3 Section 902.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD ORGANIZATION § 902.3 Board staff. The chairperson shall select the Board's executive secretary and other staff provided for in the Act. The executive secretary and staff...

22 CFR 902.3 - Board staff.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 22 Foreign Relations 2 2014-04-01 2014-04-01 false Board staff. 902.3 Section 902.3 Foreign Relations FOREIGN SERVICE GRIEVANCE BOARD ORGANIZATION § 902.3 Board staff. The chairperson shall select the Board's executive secretary and other staff provided for in the Act. The executive secretary and staff...

What Makes School Boards Effective?

ERIC Educational Resources Information Center

Zeigler, L. Harmon

Two models may be used to describe school board governance. The democratic model defines effectiveness in terms of democratic criteria. It is characterized by vigorous competition for school board positions; board members are responsive to their constituencies; the superintendent acts as policy implementor rather than policy originator, and a…

12 CFR 905.10 - Board of Directors.

Code of Federal Regulations, 2011 CFR

2011-01-01

..., functioning and organization of the Finance Board; (iii) Ensuring effective coordination and communication... and Banking FEDERAL HOUSING FINANCE BOARD FEDERAL HOUSING FINANCE BOARD ORGANIZATION AND OPERATIONS DESCRIPTION OF ORGANIZATION AND FUNCTIONS General Organization § 905.10 Board of Directors. (a) Board of...

12 CFR 905.10 - Board of Directors.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., functioning and organization of the Finance Board; (iii) Ensuring effective coordination and communication... and Banking FEDERAL HOUSING FINANCE BOARD FEDERAL HOUSING FINANCE BOARD ORGANIZATION AND OPERATIONS DESCRIPTION OF ORGANIZATION AND FUNCTIONS General Organization § 905.10 Board of Directors. (a) Board of...

Sulfate and organic matter concentration in relation to hydrogen sulfide generation at inert solid waste landfill site - Limit value for gypsum.

PubMed

Asakura, Hiroshi

2015-09-01

In order to suggest a limit value for gypsum (CaSO4) for the suppression of hydrogen sulfide (H2S) generation at an inert solid waste landfill site, the relationship between raw material (SO4 and organic matter) for H2S generation and generated H2S concentration, and the balance of raw material (SO4) and product (H2S) considering generation and outflow were investigated. SO4 concentration should be less than approximately 100mg-SO4/L in order to suppress H2S generation to below 2000ppm. Total organic carbon (TOC) concentration should be less than approximately 200mg-C/L assuming a high SO4 concentration. The limit value for SO4 in the ground is 60mg-SO4/kg with 0.011wt% as gypsum dihydrate, i.e., approximately 1/10 of the limit value in inert waste as defined by the EU Council Decision (560mg-SO4/kg-waste). The limit value for SO4 in inert waste as defined by the EU Council Decision is high and TOC is strictly excluded. The cumulative amount of SO4 outflow through the liquid phase is much larger than that through the gas phase. SO4 concentration in pore water decreases with time, reaching half the initial concentration around day 100. SO4 reduction by rainfall can be expected in the long term. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effective Superintendent-School Board Practices: Strategies for Developing and Maintaining Good Relationships with Your Board

ERIC Educational Resources Information Center

Townsend, Rene S.; Johnston, Gloria L.; Gross, Gwen E.; Lynch, Peggy; Garcy, Lorraine M.; Roberts, Benita B.; Novotney, Patricia B.

2006-01-01

Foster a strong superintendent-school board relationship centered on quality teaching and learning! This book helps current and future superintendents and school board members develop an effective governance team that prioritizes quality teaching and learning. Designed for practicing and aspiring superintendents and school board members, this…

Bringing out the Best Board Behavior

ERIC Educational Resources Information Center

Caruso, Nicholas

2004-01-01

The author's advice for for a school board superintendent is to assume incompetence instead of malevolence. Board members who behave inappropriately are a minority, and those with malicious intent are extremely rare. Most misbehaving board members act out of frustration. They may not understand the appropriate role of a board member.…

Cosmic radiation exposure of biological test systems during the EXPOSE-E mission.

PubMed

Berger, Thomas; Hajek, Michael; Bilski, Pawel; Körner, Christine; Vanhavere, Filip; Reitz, Günther

2012-05-01

In the frame of the EXPOSE-E mission on the Columbus external payload facility EuTEF on board the International Space Station, passive thermoluminescence dosimeters were applied to measure the radiation exposure of biological samples. The detectors were located either as stacks next to biological specimens to determine the depth dose distribution or beneath the sample carriers to determine the dose levels for maximum shielding. The maximum mission dose measured in the upper layer of the depth dose part of the experiment amounted to 238±10 mGy, which relates to an average dose rate of 408±16 μGy/d. In these stacks of about 8 mm height, the dose decreased by 5-12% with depth. The maximum dose measured beneath the sample carriers was 215±16 mGy, which amounts to an average dose rate of 368±27 μGy/d. These values are close to those assessed for the interior of the Columbus module and demonstrate the high shielding of the biological experiments within the EXPOSE-E facility. Besides the shielding by the EXPOSE-E hardware itself, additional shielding was experienced by the external structures adjacent to EXPOSE-E, such as EuTEF and Columbus. This led to a dose gradient over the entire exposure area, from 215±16 mGy for the lowest to 121±6 mGy for maximum shielding. Hence, the doses perceived by the biological samples inside EXPOSE-E varied by 70% (from lowest to highest dose). As a consequence of the high shielding, the biological samples were predominantly exposed to galactic cosmic heavy ions, while electrons and a significant fraction of protons of the radiation belts and solar wind did not reach the samples.

4 CFR 27.1 - The Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 4 Accounts 1 2010-01-01 2010-01-01 false The Board. 27.1 Section 27.1 Accounts GOVERNMENT... § 27.1 The Board. The Government Accountability Office Personnel Appeals Board, hereinafter the Board... of 31 U.S.C. 751. For purposes of the regulations in this part and 4 CFR part 28, a simple majority...

76 FR 40950 - Public Company Accounting Oversight Board; Notice of Filing of Proposed Board Funding Final Rules...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-12

... Accounting Oversight Board; Notice of Filing of Proposed Board Funding Final Rules for Allocation of the...'' means the portion of the accounting support fee established by the Board that is to be allocated among... support fee'' means the portion of the accounting support fee established by the Board that is to be...

HypsIRI On-Board Science Data Processing

NASA Technical Reports Server (NTRS)

Flatley, Tom

2010-01-01

Topics include On-board science data processing, on-board image processing, software upset mitigation, on-board data reduction, on-board 'VSWIR" products, HyspIRI demonstration testbed, and processor comparison.

ChalkBoard: Mapping Functions to Polygons

NASA Astrophysics Data System (ADS)

Matlage, Kevin; Gill, Andy

ChalkBoard is a domain specific language for describing images. The ChalkBoard language is uncompromisingly functional and encourages the use of modern functional idioms. ChalkBoard uses off-the-shelf graphics cards to speed up rendering of functional descriptions. In this paper, we describe the design of the core ChalkBoard language, and the architecture of our static image generation accelerator.

Advisory Boards: Gateway to Business Engagement

ERIC Educational Resources Information Center

Meeder, Hans; Pawlowski, Brett

2012-01-01

Interest has been growing in how to build or manage an effective business advisory board. Developing an advisory board is crucial to keeping CTE programs relevant and viable by engaging the support of business and industry. This article delves into how to build and manage a board, and how to re-energize boards that already exist but may be lacking.

Public Library Advisory Board Handbook.

ERIC Educational Resources Information Center

Bailey, Alvin R., Ed.; And Others

In Texas, public library advisory boards are a recent innovation that have developed as a result of the Council-Manager form of government. This handbook is a response to that development as a compilation of information on the most efficient roles and functions of advisory boards. An advisory board is appointed by the governing body of which the…

Why Not Charter School Boards?

ERIC Educational Resources Information Center

Schlechty, Phillip C.; Cole, Robert W.

1993-01-01

Claiming that individual school board members act in selfish ways, proposes electing entire school board as a slate. Board would collectively be held responsible for performance of the school system and all of its employees. State legislation would be required to specify how interested groups would select a slate and create a charter, which is the…

School Board Decision Making Practices

ERIC Educational Resources Information Center

Beard, Nicole R.

2017-01-01

The purpose of this study was to examine the way in which school boards use data when making decisions, specifically their orientations, perceptions, concerns and priorities around data. This study sought to understand how school boards use data when setting or tracking progress toward goals and aimed following the process of board use of data to…

Integration of Smart Boards in EFL Classrooms

ERIC Educational Resources Information Center

Jelyani, Saghar Javidi; Janfaza, Abusaied; Soori, Afshin

2014-01-01

The current study described the uses of smart boards in English as foreign language (EFL) classrooms. This study also investigated the role of smart boards in promoting student engagement, the benefits of smart boards for teachers, using smart boards for improving motivation, and smart boards in the service of linguistic and cultural elements. The…

Successful School Board Meetings. A Special Edition for New Jersey School Boards.

ERIC Educational Resources Information Center

Anderson, Stuart A.

This handbook was written to help school boards conduct routine business meetings more efficiently, and thereby improve their ability to reach constructive decisions and solve problems. After a brief introduction, the first chapter focuses on organizing the new school board, electing officers, adopting policies, and appointing committees. The…

Use of a Relapse Monitoring Board

PubMed Central

MacFadden, Wayne; Anand, Ravi; Khanna, Sumant; Rapaport, Mark H.; Haskins, J. Thomas; Turkoz, Ibrahim; Alphs, Larry

2011-01-01

Objective: Independent review boards can provide an objective appraisal of investigators' decisions and may be useful for determining complex primary outcomes, such as bipolar disorder relapse, in crossnational studies. This article describes the use of an independent, blinded relapse monitoring board to assess the primary outcome (relapse) in an international clinical trial of risperidone long-acting therapy adjunctive to standard-care pharmacotherapy for patients with bipolar disorder. Design: The fully autonomous relapse monitoring board was composed of a chair and two additional members—all psychiatrists and experts in the diagnostic, clinical, and therapeutic management of bipolar disorder. The relapse monitoring board met six times during the study to review patient relapse data and was charged with the responsibility of determining if the events described by investigators qualified as relapses. Additionally, the relapse monitoring board reviewed data for all randomized patients to identify any relapse events not recognized by investigators. Results: Primary efficacy results were similar and significant for investigator- and relapse monitoring board-determined relapses. Ten discrepancies were noted: two of the 42 investigator-determined relapses did not meet the intended clinical relapse threshold as determined by the relapse monitoring board; conversely, the relapse monitoring board confirmed eight relapse events not identified by investigators. The relapse monitoring board had no direct interactions with patients and had to rely on the accuracy of investigator assessments. Also, once an investigator determined a relapse and the patients discontinued the study, less information was available to the relapse monitoring board for relapse assessment. Conclusions: Use of the relapse monitoring board supported the validity of the study by incorporating a level of standardization to mitigate the risk that local practice in different cultures and medical systems

Hospital Board Oversight of Quality and Patient Safety: A Narrative Review and Synthesis of Recent Empirical Research

PubMed Central

Millar, Ross; Mannion, Russell; Freeman, Tim; Davies, Huw TO

2013-01-01

Context Recurring problems with patient safety have led to a growing interest in helping hospitals’ governing bodies provide more effective oversight of the quality and safety of their services. National directives and initiatives emphasize the importance of action by boards, but the empirical basis for informing effective hospital board oversight has yet to receive full and careful review. Methods This article presents a narrative review of empirical research to inform the debate about hospital boards’ oversight of quality and patient safety. A systematic and comprehensive search identified 122 papers for detailed review. Much of the empirical work appeared in the last ten years, is from the United States, and employs cross-sectional survey methods. Findings Recent empirical studies linking board composition and processes with patient outcomes have found clear differences between high- and low-performing hospitals, highlighting the importance of strong and committed leadership that prioritizes quality and safety and sets clear and measurable goals for improvement. Effective oversight is also associated with well-informed and skilled board members. External factors (such as regulatory regimes and the publication of performance data) might also have a role in influencing boards, but detailed empirical work on these is scant. Conclusions Health policy debates recognize the important role of hospital boards in overseeing patient quality and safety, and a growing body of empirical research has sought to elucidate that role. This review finds a number of areas of guidance that have some empirical support, but it also exposes the relatively inchoate nature of the field. Greater theoretical and methodological development is required if we are to secure more evidence-informed governance systems and practices that can contribute to safer care. PMID:24320168

Lung cancer in railroad workers exposed to diesel exhaust.

PubMed

Garshick, Eric; Laden, Francine; Hart, Jaime E; Rosner, Bernard; Smith, Thomas J; Dockery, Douglas W; Speizer, Frank E

2004-11-01

Diesel exhaust has been suspected to be a lung carcinogen. The assessment of this lung cancer risk has been limited by lack of studies of exposed workers followed for many years. In this study, we assessed lung cancer mortality in 54,973 U.S. railroad workers between 1959 and 1996 (38 years). By 1959, the U.S. railroad industry had largely converted from coal-fired to diesel-powered locomotives. We obtained work histories from the U.S. Railroad Retirement Board, and ascertained mortality using Railroad Retirement Board, Social Security, and Health Care Financing Administration records. Cause of death was obtained from the National Death Index and death certificates. There were 43,593 total deaths including 4,351 lung cancer deaths. Adjusting for a healthy worker survivor effect and age, railroad workers in jobs associated with operating trains had a relative risk of lung cancer mortality of 1.40 (95% confidence interval, 1.30-1.51). Lung cancer mortality did not increase with increasing years of work in these jobs. Lung cancer mortality was elevated in jobs associated with work on trains powered by diesel locomotives. Although a contribution from exposure to coal combustion products before 1959 cannot be excluded, these results suggest that exposure to diesel exhaust contributed to lung cancer mortality in this cohort. Key words: diesel exhaust, lung cancer, occupational exposure.

[Investigation of tibial bones of the rats exposed on board "Spacelab-2":histomorphometric analysis

NASA Technical Reports Server (NTRS)

Durnova, G. N.; Kaplanskii, A. S.; Morey-Holton, E. R.; Vorobeva, V. N.

1996-01-01

Proximal metaphyses of tibial bones from the Sprague-Dowly rats exposed in US dedicated space life sciences laboratory SLS-2 for 13-14 days and sacrificed on day 13 in microgravity and within 5 hours and 14 days following recovery were the subject of histological, histochemical, and histomorphometric analyses. After the 13-day flight of SLS-2 the rats showed initial signs of osteopenia in the spongy tissue of tibial bones, secondary spongiosis affected first. Resorption of the secondary spongiosis was consequent to enhanced resorption and inhibition of osteogenesis. In rats sacrificed within 5 hours of recovery manifestations of tibial osteopenia were more evident than in rats sacrificed during the flight. Spaceflight-induced changes in tibial spongiosis were reverse by character the amount of spongy bone was fully compensated and following 14 days of readaptation to the terrestrial gravity.

Phases, periphases, and interphases equilibrium by molecular modeling. I. Mass equilibrium by the semianalytical stochastic perturbations method and application to a solution between (120) gypsum faces

NASA Astrophysics Data System (ADS)

Pedesseau, Laurent; Jouanna, Paul

2004-12-01

The SASP (semianalytical stochastic perturbations) method is an original mixed macro-nano-approach dedicated to the mass equilibrium of multispecies phases, periphases, and interphases. This general method, applied here to the reflexive relation Ck⇔μk between the concentrations Ck and the chemical potentials μk of k species within a fluid in equilibrium, leads to the distribution of the particles at the atomic scale. The macroaspects of the method, based on analytical Taylor's developments of chemical potentials, are intimately mixed with the nanoaspects of molecular mechanics computations on stochastically perturbed states. This numerical approach, directly linked to definitions, is universal by comparison with current approaches, DLVO Derjaguin-Landau-Verwey-Overbeek, grand canonical Monte Carlo, etc., without any restriction on the number of species, concentrations, or boundary conditions. The determination of the relation Ck⇔μk implies in fact two problems: a direct problem Ck⇒μk and an inverse problem μk⇒Ck. Validation of the method is demonstrated in case studies A and B which treat, respectively, a direct problem and an inverse problem within a free saturated gypsum solution. The flexibility of the method is illustrated in case study C dealing with an inverse problem within a solution interphase, confined between two (120) gypsum faces, remaining in connection with a reference solution. This last inverse problem leads to the mass equilibrium of ions and water molecules within a 3 Å thick gypsum interface. The major unexpected observation is the repulsion of SO42- ions towards the reference solution and the attraction of Ca2+ ions from the reference solution, the concentration being 50 times higher within the interphase as compared to the free solution. The SASP method is today the unique approach able to tackle the simulation of the number and distribution of ions plus water molecules in such extreme confined conditions. This result is of prime

75 FR 34519 - SES Performance Review Board

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-17

... TRADE AND DEVELOPMENT AGENCY SES Performance Review Board AGENCY: U.S. Trade and Development... and Development Agency's Performance Review Board. FOR FURTHER INFORMATION CONTACT: Carolyn Hum... more SES Performance Review Boards. The Board shall review and evaluate the initial appraisal of a...

48 CFR 1336.602-2 - Evaluation boards.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Evaluation boards. 1336...-2 Evaluation boards. Permanent and ad hoc architect-engineer evaluation boards may include... evaluation boards should be comprised of at least a majority of government personnel. ...

75 FR 54854 - Science Advisory Board

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-09

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Science Advisory Board... the schedule and proposed agenda of a forthcoming meeting of the NOAA Science Advisory Board. The... FURTHER INFORMATION CONTACT: Dr. Cynthia Decker, Executive Director, Science Advisory Board, NOAA, Rm...

A Guide to Updating the Board's Conflict of Interest Policy. Board Basics

ERIC Educational Resources Information Center

Dreier, Alexander E.; Michaelson, Martin

2006-01-01

That college and university boards should have a policy on trustee conflict of interest is nearly universally accepted. Yet there is little consensus among institutions on just what the policy should be--and broad national consensus anytime soon is unlikely. Boards thus face a host of questions, many of which this document addresses, regarding…

77 FR 66824 - Performance Review Board Membership

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-07

... DEPARTMENT OF DEFENSE Department of the Army Performance Review Board Membership AGENCY... Performance Review Board for the Department of the Army. DATES: Effective Date: November 15, 2012. FOR FURTHER... performance review boards. The boards shall review and evaluate the initial appraisal of senior executives...

75 FR 70915 - Performance Review Board Membership

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... DEPARTMENT OF DEFENSE Department of the Army Performance Review Board Membership AGENCY... Performance Review Board for the Department of the Army. DATES: Effective Date: November 16, 2010. FOR FURTHER... performance review boards. The boards shall review and evaluate the initial appraisal of senior executives...

76 FR 70428 - Performance Review Board Membership

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-14

... DEPARTMENT OF DEFENSE Department of the Army Performance Review Board Membership AGENCY... Performance Review Board for the Department of the Army. DATES: Effective Date: November 14, 2011. FOR FURTHER... performance review boards. The boards shall review and evaluate the initial appraisal of senior executives...

78 FR 63460 - Performance Review Board Membership

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-24

... DEPARTMENT OF DEFENSE Department of the Army Performance Review Board Membership AGENCY... Performance Review Board for the Department of the Army. DATES: Effective Date: November 21, 2013. FOR FURTHER... performance review boards. The boards shall review and evaluate the initial appraisal of senior executives...

32 CFR 1602.15 - Local board of jurisdiction.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Local board of jurisdiction. 1602.15 Section... DEFINITIONS § 1602.15 Local board of jurisdiction. The local board of jurisdiction is the local board to which... determine his claim or to issue to him an order. His local board and registrant's local board refer to the...

32 CFR 1602.15 - Local board of jurisdiction.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 32 National Defense 6 2011-07-01 2011-07-01 false Local board of jurisdiction. 1602.15 Section... DEFINITIONS § 1602.15 Local board of jurisdiction. The local board of jurisdiction is the local board to which... determine his claim or to issue to him an order. His local board and registrant's local board refer to the...

Stability of hydrated minerals on Mars

NASA Astrophysics Data System (ADS)

Cloutis, Edward A.; Craig, Michael A.; Mustard, John F.; Kruzelecky, Roman V.; Jamroz, Wes R.; Scott, Alan; Bish, David L.; Poulet, François; Bibring, Jean-Pierre; King, Penelope L.

2007-10-01

The validity of recent identification of various hydrated minerals (kieserite, gypsum, hexahydrite, nontronite, chamosite, and montmorillonite) on Mars was assessed by exposing these minerals to simulated Martian surface conditions of atmospheric composition and pressure, temperature, and ultraviolet light irradiation. When exposed to such conditions the hydrated minerals exhibit in general, greater losses of interlayer H2O than structural OH. Minerals such as gypsum that contain structural H2O are more resistant to H2O loss than phyllosilicates. The partial loss of OH in some of the phyllosilicates is not accompanied by a measurable and systematic change in the wavelength position or intensity of metal-OH absorption bands. The characteristic absorption features that allow for identification of these minerals on Mars may be reduced in intensity, but are nevertheless largely preserved.

78 FR 37200 - Peanut Standards Board

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-20

...] Peanut Standards Board AGENCY: Agricultural Marketing Service, USDA. ACTION: Notice; request for... Secretary of Agriculture to establish a Peanut Standards Board (Board) for the purpose of advising the Secretary on quality and handling standards for domestically produced and imported peanuts. The initial...

76 FR 31574 - Peanut Standards Board

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-01

...] Peanut Standards Board AGENCY: Agricultural Marketing Service, USDA. ACTION: Notice; request for... Secretary of Agriculture to establish a Peanut Standards Board (Board) for the purpose of advising the Secretary on quality and handling standards for domestically produced and imported peanuts. The initial...

77 FR 56178 - Peanut Standards Board

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-12

...] Peanut Standards Board AGENCY: Agricultural Marketing Service, USDA. ACTION: Notice; request for... Secretary of Agriculture to establish a Peanut Standards Board (Board) for the purpose of advising the Secretary on quality and handling standards for domestically produced and imported peanuts. The initial...

Optimal back-to-front airplane boarding.

PubMed

Bachmat, Eitan; Khachaturov, Vassilii; Kuperman, Ran

2013-06-01

The problem of finding an optimal back-to-front airplane boarding policy is explored, using a mathematical model that is related to the 1+1 polynuclear growth model with concave boundary conditions and to causal sets in gravity. We study all airplane configurations and boarding group sizes. Optimal boarding policies for various airplane configurations are presented. Detailed calculations are provided along with simulations that support the main conclusions of the theory. We show that the effectiveness of back-to-front policies undergoes a phase transition when passing from lightly congested airplanes to heavily congested airplanes. The phase transition also affects the nature of the optimal or near-optimal policies. Under what we consider to be realistic conditions, optimal back-to-front policies lead to a modest 8-12% improvement in boarding time over random (no policy) boarding, using two boarding groups. Having more than two groups is not effective.

How Not to Be a Terrible School Board Member: Lessons for School Administrators and Board Members

ERIC Educational Resources Information Center

Mayer, Richard E.

2011-01-01

Veteran school board member, Richard E. Mayer, takes a humorous but substantive approach to the serious relationship between school administrators and board members. While the overwhelming majority of school board members have good motives, even people who mean well can make bad moves. This book shows how to prevent good intentions from creating…

77 FR 52335 - Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-29

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for Occupational Safety.... Background: The Advisory Board was established under the Energy Employees Occupational Illness Compensation...

77 FR 9254 - Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-16

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for Occupational Safety.... Background: The Advisory Board was established under the Energy Employees Occupational Illness Compensation...

77 FR 69486 - Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-19

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for Occupational Safety... people. Background: The Advisory Board was established under the Energy Employees Occupational Illness...

76 FR 5814 - Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-02

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for Occupational Safety...: The Advisory Board was established under the Energy Employees Occupational Illness Compensation...

75 FR 66769 - Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-29

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and Prevention Advisory Board on Radiation and Worker Health (ABRWH or Advisory Board), National Institute for Occupational Safety...: The Advisory Board was established under the Energy Employees Occupational Illness Compensation...

7 CFR 1207.309 - Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan Definitions § 1207.309 Board. Board means the National Potato...

7 CFR 1207.309 - Board.

Code of Federal Regulations, 2012 CFR

2012-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan Definitions § 1207.309 Board. Board means the National Potato...

7 CFR 1207.309 - Board.

Code of Federal Regulations, 2014 CFR

2014-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan Definitions § 1207.309 Board. Board means the National Potato...

7 CFR 1207.309 - Board.

Code of Federal Regulations, 2011 CFR

2011-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan Definitions § 1207.309 Board. Board means the National Potato...

7 CFR 1207.309 - Board.

Code of Federal Regulations, 2013 CFR

2013-01-01

... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE POTATO RESEARCH AND PROMOTION PLAN Potato Research and Promotion Plan Definitions § 1207.309 Board. Board means the National Potato...

Identification using versatile sampling and analytical methods of volatile compounds from Streptomyces albidoflavus grown on four humid building materials and one synthetic medium.

PubMed

Claeson, A-S; Sunesson, A-L

2005-01-01

The Streptomyces spp. form a common group of bacteria found in the indoor air of water-damaged buildings. They are known for their capability to produce compounds, like geosmin, with low odor thresholds. In this study, two strains of Streptomyces albidoflavus were cultivated on pinewood, gypsum board, particle-board, sand and tryptone glucose extract agar (TGEA). Air samples from the cultures were collected on six different adsorbents and chemosorbents to sample a wide range of compounds such as VOCs, aldehydes, amines and lightweight organic acids. The samples were analyzed with gas chromatography, high-pressure liquid chromatography and ion chromatography. Mass spectrometry was used for identification of the compounds. Metabolites were found and identified in air samples from cultures on all materials except sand. Alcohols and ketones were the dominating compound groups produced by cultures grown on pinewood and gypsum board. Few metabolites were produced on particle-board. The culture growing on TGEA produced mainly sulfur compounds and sesquiterpenes. Ammonia, methylamine, diethylamine, ethylamine and one unidentifiable amine were also found from cultivation on TGEA. The growth medium was of crucial importance to the production of potentially irritating metabolites. Microbial growth and the production of volatile metabolites is one possible explanation for building-related health problems. Streptomyces spp. are frequently found in water-damaged buildings. This study shows that Streptomyces spp. are able to produce not only odorous compounds like geosmin, but also potentially irritating compounds. This finding should be of interest in indoor air investigations.

Optimization of the level and range of working temperature of the PCM in the gypsum-microencapsulated PCM thermal energy storage unit for summer conditions in Central Poland

NASA Astrophysics Data System (ADS)

Łapka, P.; Jaworski, M.

2017-10-01

In this paper thermal energy storage (TES) unit in a form of a ceiling panel made of gypsum-microencapsulated PCM composite with internal U-shaped channels was considered and optimal characteristics of the microencapsulated PCM were determined. This panel may be easily incorporated into, e.g., an office or residential ventilation system in order to reduce daily variations of air temperature during the summer without additional costs related to the consumption of energy for preparing air parameters to the desired level. For the purpose of the analysis of heat transfer in the panel, a novel numerical simulator was developed. The numerical model consists of two coupled parts, i.e., the 1D which deals with the air flowing through the U-shaped channel and the 3D which deals with heat transfer in the body of the panel. The computational tool was validated based on the experimental study performed on the special set-up. Using this tool an optimization of parameters of the gypsum-microencapsulated PCM composite was performed in order to determine its most appropriate properties for the application under study. The analyses were performed for averaged local summer conditions in Warsaw, Poland.

7 CFR 1205.308 - Cotton Board.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Cotton Board. 1205.308 Section 1205.308 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Cotton Research and Promotion Order Definitions § 1205.308 Cotton Board. Cotton Board means the administrative...

7 CFR 1205.308 - Cotton Board.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 10 2012-01-01 2012-01-01 false Cotton Board. 1205.308 Section 1205.308 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Cotton Research and Promotion Order Definitions § 1205.308 Cotton Board. Cotton Board means the administrative...

7 CFR 1205.308 - Cotton Board.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 10 2011-01-01 2011-01-01 false Cotton Board. 1205.308 Section 1205.308 Agriculture... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Cotton Research and Promotion Order Definitions § 1205.308 Cotton Board. Cotton Board means the administrative...

7 CFR 1205.308 - Cotton Board.

Code of Federal Regulations, 2013 CFR