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Sample records for drying cycle loveday

  1. Dry process dependency of dupic fuel cycle

    SciTech Connect

    Park, Kwangheon; Whang, Juho; Kim, Yun-goo; Kim, Heemoon

    1996-12-31

    During the Dry Process, volatile and semi-volatile elements are released from the fuel. The effects of these released radioactive nuclides on DUPIC fuel cycle are analyzed from the view-point of radiation hazard, decay beat, and hazard index. Radiation hazard of fresh and spent DUPIC fuel is sensitive to the method of Dry Process. Decay beat of the fuel is also affected. Hazard index turned out not to be dependent on Dry Process.

  2. Correlation of laboratory and production freeze drying cycles.

    PubMed

    Kuu, Wei Y; Hardwick, Lisa M; Akers, Michael J

    2005-09-30

    The purpose of this study was to develop the correlation of cycle parameters between a laboratory and a production freeze-dryer. With the established correlation, key cycle parameters obtained using a laboratory dryer may be converted to those for a production dryer with minimal experimental efforts. In order to develop the correlation, it was important to consider the contributions from the following freeze-drying components: (1) the dryer, (2) the vial, and (3) the formulation. The critical parameters for the dryer are the shelf heat transfer coefficient and shelf surface radiation emissivity. The critical parameters for the vial are the vial bottom heat transfer coefficients (the contact parameter Kcs and separation distance lv), and vial top heat transfer coefficient. The critical parameter of the formulation is the dry layer mass transfer coefficient. The above heat and mass transfer coefficients were determined by freeze-drying experiments in conjunction with mathematical modeling. With the obtained heat and mass transfer coefficients, the maximum product temperature, Tbmax, during primary drying was simulated using a primary drying subroutine as a function of the shelf temperature and chamber pressure. The required shelf temperature and chamber pressure, in order to perform a successful cycle run without product collapse, were then simulated based on the resulting values of Tbmax. The established correlation approach was demonstrated by the primary drying of the model formulation 5% mannitol solution. The cycle runs were performed using a LyoStar dryer as the laboratory dryer and a BOC Edwards dryer as the production dryer. The determined normalized dried layer mass transfer resistance for 5% mannitol is expressed as RpN=0.7313+17.19l, where l is the receding dry layer thickness. After demonstrating the correlation approach using the model formulation 5% mannitol, a practical comparison study was performed for the actual product, the lactate dehydrogenase

  3. Water cycle of a seasonally dry tropical forest (Southern Vietnam)

    NASA Astrophysics Data System (ADS)

    Kuricheva, O. A.; Avilov, V. C.; Dinh, Duy Ba; Kurbatova, J. A.

    2015-12-01

    How does the activity of the ecosystem of monsoon tropical forest decrease during the dry season of more than 4 months? To answer this question, the dynamics of evapotranspiration is analyzed in the national park of Cát Tiên (Southern Vietnam) using continuous eddy covariance and meteorological dataset for 2012-2013. A comparison of evapotranspiration between Cát Tiên and 21 sites in different tropical forests over the world is performed. It is shown that the abundance of resources of energy and moisture in the annual cycle, as well as the storage of water from the rainy season allows monsoon ecosystem to implement the proactive vegetation during the dry season and make specificity of ecosystem energy and water fluxes in Cát Tiên forest similar to the rainforests.

  4. Colloid Mobilization in a Fractured Soil during Dry-Wet Cycles: Role of Drying Duration and Flow Path Permeability.

    PubMed

    Mohanty, Sanjay K; Saiers, James E; Ryan, Joseph N

    2015-08-04

    In subsurface soils, colloids are mobilized by infiltrating rainwater, but the source of colloids and the process by which colloids are generated between rainfalls are not clear. We examined the effect of drying duration and the spatial variation of soil permeability on the mobilization of in situ colloids in intact soil cores (fractured and heavily weathered saprolite) during dry-wet cycles. Measuring water flux at multiple sampling ports at the core base, we found that water drained through flow paths of different permeability. The duration of antecedent drying cycles affected the amount of mobilized colloids, particularly in high-flux ports that received water from soil regions with a large number of macro- and mesopores. In these ports, the amount of mobilized colloids increased with increased drying duration up to 2.5 days. For drying durations greater than 2.5 days, the amount of mobilized colloids decreased. In contrast, increasing drying duration had a limited effect on colloid mobilization in low-flux ports, which presumably received water from soil regions with fewer macro- and mesopores. On the basis of these results, we attribute this dependence of colloid mobilization upon drying duration to colloid generation from dry pore walls and distribution of colloids in flow paths, which appear to be sensitive to the moisture content of soil after drying and flow path permeability. The results are useful for improving the understanding of colloid mobilization during fluctuating weather conditions.

  5. Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

    SciTech Connect

    Moisseytsev, A.; Sienicki, J. J.; Lv, Q.

    2016-07-28

    Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO2) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO2 Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO2 Brayton cycle is that it enables dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately

  6. Thermodynamic analysis of organic Rankine cycle using dry working fluids

    SciTech Connect

    Wang, S.K.; Hung, T.C.

    1998-12-31

    Utilization of waste heat is not economically incentive to the industry once the temperature of the waste heat drops to a certain level. This is primarily due to a low efficiency when converting the energy of the waste heat to some forms of useful power. A Rankine cycle using organic fluids as working fluids, called organic Rankine cycle (ORC), is potentially feasible in recovering low-enthalpy containing heat sources. Nevertheless, an efficient operation of the ORC depends heavily on two factors: working conditions of the cycle and the thermodynamic properties of the working fluids. The main objective of this study is to investigate the effects of these two factors on the performance of the ORC. The working fluids under investigation are: benzene (C{sub 6}H), toluene (C{sub 7}H{sub 8}), p-xylene (C{sub 8}H{sub 10}), R113 and R123. Irreversibility of a system using various working fluids was studied since it represents the energy balance in recovering the waste heat. The study shows that the system efficiency increases as the inlet pressure of the turbine increases regardless of the working fluid used. Among the working fluids under investigation, p-xylene shows the highest efficiency while benzene the lowest. The study also shows that irreversibility depends on the type of heat source. Generally speaking, p-xylene has the lowest irreversibility in recovering a high temperature waste heat while R113 and R123 have a better performance in recovering a low temperature waste heat. In addition, an economic feasibility of ORC using various working fluids is given for ORC`s with commercial capacities.

  7. Drying-rewetting cycles affect fungal and bacterial growth differently in an arable soil.

    PubMed

    Bapiri, Azadeh; Bååth, Erland; Rousk, Johannes

    2010-08-01

    Drying and rewetting is a frequent physiological stress for soil microbial communities; a stress that is predicted to grow more influential with future climate change. We investigated the effect of repeated drying-rewetting cycles on bacterial (leucine incorporation) and fungal (acetate in ergosterol incorporation) growth, on the biomass concentration and composition (PLFA), and on the soil respiration. Using different plant material amendments, we generated soils with different initial fungal:bacterial compositions that we exposed to 6-10 repetitions of a drying-rewetting cycle. Drying-rewetting decreased bacterial growth while fungal growth remained unaffected, resulting in an elevated fungal:bacterial growth ratio. This effect was found irrespective of the initial fungal:bacterial biomass ratio. Many drying-rewetting cycles did not, however, affect the fungal:bacterial growth ratio compared to few cycles. The biomass response of the microbial community differed from the growth response, with fungal and total biomass only being slightly negatively affected by the repeated drying-rewetting. The discrepancy between growth- and biomass-based assessments underscores that microbial responses to perturbations might previously have been misrepresented with biomass-based assessments. In light of this, many aspects of environmental microbial ecology may need to be revisited with attention to what measure of the microbial community is relevant to study.

  8. [Dynamic changes of soil amino sugar contents under drying and wetting cycle].

    PubMed

    Zhang, Wei; Han, Yong-Jiao; He, Hong-Bo; Xie, Hong-Tu; Zhang, Xu-Dong

    2012-04-01

    A soil incubation test was conducted to study the quantitative changes of three amino sugars (glucosamine, muramic acid, and galactosamine) derived from microbes under drying and wetting cycle, and to analyze the relative contribution of soil bacteria and fungi to the turnover of soil organic matter by using the measured glucosamine/muramic acid ratio. Under continuous wetting, the degradation of bacteria-derived muramic acid was faster than that of fungi-derived glucosamine, and the degradation rate of galactosamine was the lowest. Drying and wetting cycle altered the degradation characteristics of the three amino sugars. As compared with that under continuous wetting, the degradation rate of bacteria-derived muramic acid at the prophase of drying and wetting was faster than that of fungi-derived glucosamine, and, with the increasing frequency of drying and wetting cycle, the degradation rate of fungi-derived glucosamine was faster than that of bacteria-derived muramic acid. These results indicated that drying and wetting cycle changed the course of the microbial transformation of soil amino sugar-derived nitrogen.

  9. Noninvasive characterization of the fission yeast cell cycle by monitoring dry mass with digital holographic microscopy

    NASA Astrophysics Data System (ADS)

    Rappaz, Benjamin; Cano, Elena; Colomb, Tristan; Kühn, Jonas; Depeursinge, Christian; Simanis, Viesturs; Magistretti, Pierre J.; Marquet, Pierre

    2009-05-01

    Digital holography microscopy (DHM) is an optical technique which provides phase images yielding quantitative information about cell structure and cellular dynamics. Furthermore, the quantitative phase images allow the derivation of other parameters, including dry mass production, density, and spatial distribution. We have applied DHM to study the dry mass production rate and the dry mass surface density in wild-type and mutant fission yeast cells. Our study demonstrates the applicability of DHM as a tool for label-free quantitative analysis of the cell cycle and opens the possibility for its use in high-throughput screening.

  10. Impact of Wetting/Oven-Drying Cycles on the Mechanical and Physical Properties of Birch Plywood

    NASA Astrophysics Data System (ADS)

    Sooru, M.; Kasepuu, K.; Kask, R.; Lille, H.

    2015-11-01

    The objective of this study was to explore some physical and mechanical properties and the dimensional stability of birch (Betula sp.) nine-ply veneers glued with phenol-formaldehyde (PF) after 10 cycles of soaking/oven-drying. The properties to be determined were bending strength (BS), modulus of elasticity in bending (MOE), Janka hardness (JH) and thickness swelling (TS), which were tested according to the European Standards (EN). An analytical equation was used for approximation of the change in the physical and mechanical properties of the samples depending on the number of cycles. It was shown that the values of the studied properties were affected most by the first soaking and drying cycles after which BS and MOE decreased continuously while the values of JH and TS stabilized. After 10 cycles the final values of BS, MOE, JH and TS accounted for 75-81%, 95%, 82% and 98.5% of the initial values, respectively.

  11. Moisture measurement: a new method for monitoring freeze-drying cycles.

    PubMed

    Bardat, A; Biguet, J; Chatenet, E; Courteille, F

    1993-01-01

    Quality of the final product largely depends on the freeze-drying process. In turn this largely depends on an adequate control of the amount of residual moisture after freeze-drying. Measuring this amount in the chamber of the freeze-dryer to determine the end point of sublimation and the end point of secondary drying provides a reliable control with regard to the methods traditionally used (for example rapid increase in product temperature). The purpose of this study is to evaluate the benefits and disadvantages of the different methods recommended for the monitoring of a freeze-drying cycle. Two systems for the measurement of the moisture in the freeze dryer are evaluated here: the Pirani vacuum gauge, and the moisture sensor. The moisture sensor appears to be the most sensitive and reliable way of determining both the end of sublimation and the end of secondary drying of the full load batch when placed on a freeze-dryer. The immediate benefit for the industry is to allow to scale-up without the risks of under or over estimating the freeze-drying cycle.

  12. Effect of drying-wetting cycles on leaching behavior of cement solidified lead-contaminated soil.

    PubMed

    Li, Jiang-Shan; Xue, Qiang; Wang, Ping; Li, Zhen-Ze; Liu, Lei

    2014-12-01

    Lead contaminated soil was treated by different concentration of ordinary Portland cement (OPC). Solidified cylindrical samples were dried at 40°C in oven for 48 h subsequent to 24h of immersing in different solution for one drying-wetting. 10 cycles were conducted on specimens. The changes in mass loss of specimens, as well as leaching concentration and pH of filtered leachates were studied after each cycle. Results indicated that drying-wetting cycles could accelerate the leaching and deterioration of solidified specimens. The cumulative leached lead with acetic acid (pH=2.88) in this study was 109, 83 and 71 mg respectively for solidified specimens of cement-to-dry soil (C/Sd) ratios 0.2, 0.3 and 0.4, compared to 37, 30, and 25mg for a semi-dynamic leaching test. With the increase of cycle times, the cumulative mass loss of specimens increased linearly, but pH of filtered leachates decreased. The leachability and deterioration of solidified specimens increased with acidity of solution. Increases of C/Sd clearly reduced the leachability and deterioration behavior.

  13. Do drying and rewetting cycles modulate effects of sulfadiazine spiked manure in soil?

    PubMed

    Jechalke, Sven; Radl, Viviane; Schloter, Michael; Heuer, Holger; Smalla, Kornelia

    2016-05-01

    Naturally occurring drying-rewetting events in soil have been shown to affect the dissipation of veterinary antibiotics entering soil by manure fertilization. However, knowledge of effects on the soil microbial community structure and resistome is scarce. Here, consequences of drying-rewetting cycles on effects of sulfadiazine (SDZ) in soil planted with Dactylis glomerata L. were investigated in microcosms. Manure containing SDZ or not was applied to the pregrown grass and incubated for 56 days in a climate chamber. Water was either added daily or reduced during two drying events of 7 days, each followed by a recovery phase. Total community DNA was analyzed to reveal the effects on the bacterial community structure and on the abundance of sul1, sul2, intI1 ,intI2, qacE+qacEΔ1, traN and korB genes relative to 16S rRNA genes. 16S rRNA gene-based DGGE fingerprints indicated that drying-rewetting cycles modulated the effects of SDZ on the bacterial community structure in the soil. Furthermore, the SDZ treatment increased the relative abundance of sulfonamide resistance and integrase genes compared to the control. However, this increase was not different between moisture regimes, indicating that drying-rewetting had only a negligible effect on the selection of the resistome by SDZ in the manured soil.

  14. Corrosion of weathering steel and iron under wet-dry cycling conditions: Influence of the rise of temperature during the dry period

    NASA Astrophysics Data System (ADS)

    Davalos, J.; Gracia, M.; Marco, J. F.; Gancedo, J. R.

    1992-04-01

    The effect of a dry-hot period on the SO2 corrosion of weatherig steel and pure iron under wet-dry cycling was investigated. Corrosion products were identified by Mössbauer spectroscopy and X-ray powder diffraction. The formation of an intermediate corrosion layer of spm α-FeOOH only on weathering steel was the most significant result.

  15. Investigation of design space for freeze-drying: use of modeling for primary drying segment of a freeze-drying cycle.

    PubMed

    Koganti, Venkat Rao; Shalaev, Evgenyi Y; Berry, Mark R; Osterberg, Thomas; Youssef, Maickel; Hiebert, David N; Kanka, Frank A; Nolan, Martin; Barrett, Rosemary; Scalzo, Gioval; Fitzpatrick, Gillian; Fitzgibbon, Niall; Luthra, Sumit; Zhang, Liling

    2011-09-01

    In this work, we explore the idea of using mathematical models to build design space for the primary drying portion of freeze-drying process. We start by defining design space for freeze-drying, followed by defining critical quality attributes and critical process parameters. Then using mathematical model, we build an insilico design space. Input parameters to the model (heat transfer coefficient and mass transfer resistance) were obtained from separate experimental runs. Two lyophilization runs are conducted to verify the model predictions. This confirmation of the model predictions with experimental results added to the confidence in the insilico design space. This simple step-by-step approach allowed us to minimize the number of experimental runs (preliminary runs to calculate heat transfer coefficient and mass transfer resistance plus two additional experimental runs to verify model predictions) required to define the design space. The established design space can then be used to understand the influence of critical process parameters on the critical quality attributes for all future cycles.

  16. Quantification of hysteresis effects on a soil subjected to drying and wetting cycles

    NASA Astrophysics Data System (ADS)

    Rafraf, Samia; Guellouz, Lamia; Guiras, Houda; Bouhlila, Rachida

    2016-10-01

    A quantitative description of soil hysteretic response during drying-wetting cycles is required to improve prediction of the soil water retention model. The objective of the study is to quantify the degree of hysteresis, which is helpful to evaluate the precision of soil water flow calculation. A new procedure to quantify the degree of hysteresis is presented. The Arya-Paris model allows assessment of hysteresis effects from initial drying curves, dynamic contact angles, degree of hysteresis value, and maximum difference value between drying and subsequent wetting curves. The experimental results show that the degree of hysteresis varies with the particle size, bulk density, void ratio, initial water content, and contact angle of the soil. The new findings can be very useful in modelling soil water flows.

  17. Effects of Wet and Dry Cycles on TNT Losses From Soils.

    DTIC Science & Technology

    1992-11-01

    compound or its microbial or photochemical transformation products as the soil undergoes wetting and drying cycles. Spe - cific objectives of the study...15. NUMBER OF PAGES 18 Degradation Explosives TNT 16 . PRICE CODE Environmental fate Soils 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19...Form 298 (Rev 2-89) Pfrnp rbod bv ANi Std 19-8 2,8 102 13. (Concluded). passed through XAD resin to trap volatile organic compounds followed by four

  18. Effect of repeated drying-wetting-freezing-thawing cycles on the active soil organic carbon pool

    NASA Astrophysics Data System (ADS)

    Semenov, V. M.; Kogut, B. M.; Lukin, S. M.

    2014-04-01

    Samples of soddy-podzolic soil (long-term overgrown fallow and continuous bare fallow), gray forest soil (forest, farming agrocenosis), and a typical chernozem (virgin steppe, forest area, farming agrocenosis, continuous bare fallow) have been incubated under stable conditions; other samples of these soils have been subjected to six drying-wetting-incubation-freezing-thawing-incubation cycles during 136 days. The wetting of dried soils and the thawing of frozen soils result in an abrupt but short increase in the emission rate of C-CO2 by 2.7-12.4 and 1.6-2.7 times, respectively, compared to the stable incubation conditions. As the soil is depleted in potentially mineralizable organic matter, the rate of the C-CO2 emission pulses initiated by disturbing impacts decreases. The cumulative extra production of C-CO2 by soils of natural lands for six cycles makes up 21-40% of that in the treatments with stable incubation conditions; the corresponding value for cultivated soils, including continuous clean fallow, is in the range of 45-82%. The content of potentially mineralizable organic matter in the soils subjected to recurrent drying-wetting-freezingthawing cycles decreased compared to the soils without disturbing impacts by 1.6-4.4 times, and the mineralization constants decreased by 1.9-3.6 times. It has been emphasized that the cumulative effect of drying-wetting-freezing-thawing cycles is manifested not only in the decrease in the total Corg from the soil but also in the reduction of the mineralization potential of the soil organic matter.

  19. The corrosion products of weathering steel and pure iron in simulated wet-dry cycles

    NASA Astrophysics Data System (ADS)

    Dávalos, J.; Marco, J. F.; Gracia, M.; Gancedo, J. R.

    1991-11-01

    Mössbauer spectroscopy and X-ray diffraction were used to establish the composition of the rust formed on pure iron and weathering steel after exposure to several wet-dry cycles in an SO2-polluted atmosphere. α-FeOOH poorly crystallized and quasi amorphous ferrihydrite are identified as the main corrosion products. The rust has different particle size for iron and weathering steel samples.

  20. Impact of repeated dry-wet cycles on soil CO2 efflux in a beech forest

    NASA Astrophysics Data System (ADS)

    Leitner, Sonja; Saronjic, Nermina; Kobler, Johannes; Holtermann, Christian; Zechmeister-Boltenstern, Sophie; Zimmermann, Michael

    2015-04-01

    Climate change research predicts that both frequency and intensity of weather extremes such as severe droughts and heavy rainfall events will increase in mid Europe over the next decades. Because soil moisture is one of the major factors controlling microbially-driven soil processes, a changed moisture regime will impact soil organic matter (SOM) decomposition and nutrient cycling. This in turn can lead to feedback effects between altered precipitation and changed soil CO2 fluxes which can intensify climate change. Soil microorganisms can go into a state of dormancy or form inactive cysts to protect themselves from osmotic stress during soil drying. However, severe droughts increase microbial mortality which slows down SOM decomposition and decreases soil CO2 efflux. The rewetting of dry soil, on the other hand, causes large CO2 emissions, which is also known as the "Birch effect". Until today it is not clear whether these CO2 peaks outweigh the drought-induced decrease of total CO2 efflux. To investigate the impact of repeated dry-wet cycles on soil CO2 efflux we are conducting a precipitation manipulation experiment in a temperate Austrian beech forest. Roofs exclude rainfall and simulate drought periods, and heavy rainfall events are simulated with a sprinkler system. We apply repeated dry-wet cycles in two intensities: one treatment receives 6 cycles of 1 month drought followed by 75mm irrigation, and a parallel treatment receives 3 cycles of 2 months drought followed by 150mm irrigation. Soil CO2 efflux is constantly monitored with an automated flux chamber system, and environmental parameters are recorded via dataloggers. Our results show that droughts significantly reduce soil CO2 effluxes, and that the reductions depend on the length of the drought periods, with longer droughts leading to stronger reductions of CO2 effluxes. In the first 24 to 48h after rewetting, CO2 emissions strongly increased, and then slowly decreased again. Soil CO2 efflux was

  1. Microstructural and chemical effects of wet/dry cycling on pulp fiber-cement composites

    SciTech Connect

    Mohr, B.J. . E-mail: bmohr@tntech.edu; Biernacki, J.J.; Kurtis, K.E.

    2006-07-15

    The microstructural and chemical mechanisms responsible for pulp fiber-cement composite degradation during wet/dry cycling are being investigated through environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), and mechanical testing. Based on these results, a three-part progressive degradation mechanism for cast-in-place kraft pulp fiber-cement composites is proposed, which involves: (1) initial fiber-cement or fiber interlayer debonding (2) reprecipitation of needle-like or sheath-like ettringite within the void space at the former fiber-cement interface or between the S1 and S2 fiber layers, and (3) fiber mineralization due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. This investigation also revealed that kraft pulp fibers exhibit poor resistance to degradation due to their inferior dimensional stability, as compared to thermomechanical pulp (TMP) fibers. TMP fibers contain significant amounts of lignin, which is alkali sensitive. Despite this, TMP fiber-cement composite exhibit improved resistance to degradation during wet/dry cycling. It is proposed that this improvement in durability may be attributed to the presence of lignin in the cell wall restricting fiber dimensional changes during wetting and drying, and hence, minimizing fiber-cement debonding. Additionally, it is proposed that lignin acts as physical barrier to calcium hydroxide formation within the fiber cell wall, minimizing fiber mineralization of TMP fibers.

  2. Quality by design: scale-up of freeze-drying cycles in pharmaceutical industry.

    PubMed

    Pisano, Roberto; Fissore, Davide; Barresi, Antonello A; Rastelli, Massimo

    2013-09-01

    This paper shows the application of mathematical modeling to scale-up a cycle developed with lab-scale equipment on two different production units. The above method is based on a simplified model of the process parameterized with experimentally determined heat and mass transfer coefficients. In this study, the overall heat transfer coefficient between product and shelf was determined by using the gravimetric procedure, while the dried product resistance to vapor flow was determined through the pressure rise test technique. Once model parameters were determined, the freeze-drying cycle of a parenteral product was developed via dynamic design space for a lab-scale unit. Then, mathematical modeling was used to scale-up the above cycle in the production equipment. In this way, appropriate values were determined for processing conditions, which allow the replication, in the industrial unit, of the product dynamics observed in the small scale freeze-dryer. This study also showed how inter-vial variability, as well as model parameter uncertainty, can be taken into account during scale-up calculations.

  3. Understanding spatial heterogeneity in soil carbon and nitrogen cycling in regenerating tropical dry forests

    NASA Astrophysics Data System (ADS)

    Waring, B. G.; Powers, J. S.; Branco, S.; Adams, R.; Schilling, E.

    2015-12-01

    Tropical dry forests (TDFs) currently store significant amounts of carbon in their biomass and soils, but these highly seasonal ecosystems may be uniquely sensitive to altered climates. The ability to quantitatively predict C cycling in TDFs under global change is constrained by tremendous spatial heterogeneity in soil parent material, land-use history, and plant community composition. To explore this variation, we examined soil carbon and nitrogen dynamics in 18 permanent plots spanning orthogonal gradients of stand age and soil fertility. Soil C and N pools, microbial biomass, and microbial extracellular enzyme activities were most variable at small (m2) spatial scales. However, the ratio of organic vs. inorganic N cycling was consistently higher in forest stands dominated by slow-growing, evergreen trees that associate with ectomycorrhizal fungi. Similarly, although bulk litter stocks and turnover rates varied greatly among plots, litter decomposition tended to be slower in ectomycorrhizae-dominated stands. Soil N cycling tended to be more conservative in older plots, although the relationship between stand age and element cycling was weak. Our results emphasize that microscale processes, particularly interactions between mycorrhizal fungi and free-living decomposers, are important controls on ecosystem-scale element cycling.

  4. The Resilience of Microbial Community under Drying and Rewetting Cycles of Three Forest Soils

    PubMed Central

    Zhou, Xue; Fornara, Dario; Ikenaga, Makoto; Akagi, Isao; Zhang, Ruifu; Jia, Zhongjun

    2016-01-01

    Forest soil ecosystems are associated with large pools and fluxes of carbon (C) and nitrogen (N), which could be strongly affected by variation in rainfall events under current climate change. Understanding how dry and wet cycle events might influence the metabolic state of indigenous soil microbes is crucial for predicting forest soil responses to environmental change. We used 454 pyrosequencing and quantitative PCR to address how present (DNA-based) and potentially active (RNA-based) soil bacterial communities might response to the changes in water availability across three different forest types located in two continents (Africa and Asia) under controlled drying and rewetting cycles. Sequencing of rRNA gene and transcript indicated that Proteobacteria, Actinobacteria, and Acidobacteria were the most responsive phyla to changes in water availability. We defined the ratio of rRNA transcript to rRNA gene abundance as a key indicator of potential microbial activity and we found that this ratio was increased following soil dry-down process whereas it decreased after soil rewetting. Following rewetting Crenarchaeota-like 16S rRNA gene transcript increased in some forest soils and this was linked to increases in soil nitrate levels suggesting greater nitrification rates under higher soil water availability. Changes in the relative abundance of (1) different microbial phyla and classes, and (2) 16S and amoA genes were found to be site- and taxa-specific and might have been driven by different life-strategies. Overall, we found that, after rewetting, the structure of the present and potentially active bacterial community structure as well as the abundance of bacterial (16S), archaeal (16S) and ammonia oxidizers (amoA), all returned to pre-dry-down levels. This suggests that microbial taxa have the ability to recover from desiccation, a critical response, which will contribute to maintaining microbial biodiversity in harsh ecosystems under environmental perturbations

  5. Life cycle assessment of superheated steam drying technology as a novel cow manure management method.

    PubMed

    Hanifzadeh, Mohammadmatin; Nabati, Zahra; Longka, Pairote; Malakul, Pomthong; Apul, Defne; Kim, Dong-Shik

    2017-09-01

    Common methods of managing dairy manure are directly applying it to the farm field as a fertilizer. For direct application without any type of treatment, the majority of nutrients in the manure run off to the local river and lake during precipitation periods. The algae bloom is one of the environmental outcomes due to eutrophication of the lakes, which may jeopardize the quality of drinking water. In this study, superheated steam drying (SSD) technology is investigated as an alternative manure management method. Rapidly dried cow manure can be used as alternative fuel. Evaluations of energy payback time (EPBT) and life cycle assessment (LCA) of the SSD technology are presented in the SSD scenario and the results are compared with those of the direct field application (FA) of fresh manure and anaerobic digestion (AD). The heat required for the generation of superheated steam in the SSD scenario is provided from combustion of the dry manure to reduce energy costs. The results for the SSD process show 95% and 70% lower eutrophication and global warming potential in comparison to the FA scenario. Acidification potential for SSD turned out to be 35% higher than FA. The comparison of SSD with AD for their EPBT and normalized impacts indicated that the proposed SSD scenario has higher environmental sustainability than AD (70% lower impact), and is likely an economically better choice compared to conventional AD method (87% lower EPBT) for the future investment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Release of aged 14C-atrazine residues from soil facilitated by dry-wet cycles

    NASA Astrophysics Data System (ADS)

    Jablonowski, N. D.; Yu, K.; Koeppchen, S.; Burauel, P.

    2012-04-01

    Intermittent dry-wet cycles may have an important effect on soil structure and aged pesticide residues release (1). A laboratory study was conducted to assess the maximum potential of water extractable aged atrazine residues influenced by soil drying and wetting. The used soil was obtained from an outdoor lysimeter (gleyic cambisol; Corg: 1.45%), containing environmentally aged (22 years) 14C-atrazine residues. For the experiment, soil from 0-10 cm depth was used since most residual 14C activity was previously found in this layer (2,3). Triplicate soil samples with a residual water content of approx. 8% were either dried (45° C) prior water addition or directly mixed with distilled water (soil+water: 1+2, w:w). The samples were shaken (150 rmp, 60 min, at 21° C), centrifuged (approx. 2000 g), and the supernatants were filtered. Water-extracted residual 14C activity was detected via liquid scintillation counter. The total water-extracted 14C activity (the amount of residual 14C activity in a sample equals 100%) was significantly higher (p

  7. Dry/Wet cycles change the activity and population dynamics of methanotrophs in rice field soil.

    PubMed

    Ma, Ke; Conrad, Ralf; Lu, Yahai

    2013-08-01

    The methanotrophs in rice field soil are crucial in regulating the emission of methane. Drainage substantially reduces methane emission from rice fields. However, it is poorly understood how drainage affects microbial methane oxidation. Therefore, we analyzed the dynamics of methane oxidation rates, composition (using terminal restriction fragment length polymorphism [T-RFLP]), and abundance (using quantitative PCR [qPCR]) of methanotroph pmoA genes (encoding a subunit of particulate methane monooxygenase) and their transcripts over the season and in response to alternate dry/wet cycles in planted paddy field microcosms. In situ methane oxidation accounted for less than 15% of total methane production but was enhanced by intermittent drainage. The dry/wet alternations resulted in distinct effects on the methanotrophic communities in different soil compartments (bulk soil, rhizosphere soil, surface soil). The methanotrophic communities of the different soil compartments also showed distinct seasonal dynamics. In bulk soil, potential methanotrophic activity and transcription of pmoA were relatively low but were significantly stimulated by drainage. In contrast, however, in the rhizosphere and surface soils, potential methanotrophic activity and pmoA transcription were relatively high but decreased after drainage events and resumed after reflooding. While type II methanotrophs dominated the communities in the bulk soil and rhizosphere soil compartments (and to a lesser extent also in the surface soil), it was the pmoA of type I methanotrophs that was mainly transcribed under flooded conditions. Drainage affected the composition of the methanotrophic community only minimally but strongly affected metabolically active methanotrophs. Our study revealed dramatic dynamics in the abundance, composition, and activity of the various type I and type II methanotrophs on both a seasonal and a spatial scale and showed strong effects of dry/wet alternation cycles, which enhanced

  8. Dry/Wet Cycles Change the Activity and Population Dynamics of Methanotrophs in Rice Field Soil

    PubMed Central

    Ma, Ke; Conrad, Ralf

    2013-01-01

    The methanotrophs in rice field soil are crucial in regulating the emission of methane. Drainage substantially reduces methane emission from rice fields. However, it is poorly understood how drainage affects microbial methane oxidation. Therefore, we analyzed the dynamics of methane oxidation rates, composition (using terminal restriction fragment length polymorphism [T-RFLP]), and abundance (using quantitative PCR [qPCR]) of methanotroph pmoA genes (encoding a subunit of particulate methane monooxygenase) and their transcripts over the season and in response to alternate dry/wet cycles in planted paddy field microcosms. In situ methane oxidation accounted for less than 15% of total methane production but was enhanced by intermittent drainage. The dry/wet alternations resulted in distinct effects on the methanotrophic communities in different soil compartments (bulk soil, rhizosphere soil, surface soil). The methanotrophic communities of the different soil compartments also showed distinct seasonal dynamics. In bulk soil, potential methanotrophic activity and transcription of pmoA were relatively low but were significantly stimulated by drainage. In contrast, however, in the rhizosphere and surface soils, potential methanotrophic activity and pmoA transcription were relatively high but decreased after drainage events and resumed after reflooding. While type II methanotrophs dominated the communities in the bulk soil and rhizosphere soil compartments (and to a lesser extent also in the surface soil), it was the pmoA of type I methanotrophs that was mainly transcribed under flooded conditions. Drainage affected the composition of the methanotrophic community only minimally but strongly affected metabolically active methanotrophs. Our study revealed dramatic dynamics in the abundance, composition, and activity of the various type I and type II methanotrophs on both a seasonal and a spatial scale and showed strong effects of dry/wet alternation cycles, which enhanced

  9. Wet-dry cycles effect on ash water repellency. A laboratory experiment.

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Cerdà, Artemi; Oliva, Marc; Mataix, Jorge; Jordán, Antonio

    2014-05-01

    In the immediate period after the fire, the ash layer has a strong influence on soil hydrological processes, as runoff, infiltration and erosion. Ash is very dynamic in the space and time. Until the first rainfall periods, ash is (re)distributed by the wind. After it can cover the soil surface, infiltrate or transported to other areas by water transport (Pereira et al., 2013a, b). This will have strong implications on nutrient redistribution and vegetation recovery. Ash layer may affect soil water repellency in different ways, depending on fire severity, soil properties and vegetation. Ash produced at low temperatures after low-severity burning is usually hydrophobic (Bodi et al., 2011, 2012). Wet-dry cycles have implications on ash physical and chemical properties, changing their effects in space and time. The aim of this study is to analyse the effects of fire temperature and severity on ash water repellency. Pinus sylvestris needles were collected in a Lithuania forest in Dzukija National Park (53º 54' N and 24º 22' E), transported to laboratory and washed with deionized water to remove soil particles and other residues. Needle samples were dried during 24 hours and exposed to different temperatures: 200, 300, 400 and 500 ºC, during 2 hours. Ash colour was analysed according to the Munsell Soil Color charts. Ash was black (10 YR 2/1) at 200 ºC, very dark grey (10YR 3/1) at 300 ºC, gray (10YR 5/1) at 400 ºC and light gray (10YR 7/1) at 500 ºC. Ten samples of ash released after each treatment were placed in plastic dishes (50 mm in diameter) in an amount enough to form a 5 mm thick layer, and ash water repellency was measured according to the Water Drop Penetration Test. Later, ash was carefully wetted with 15 ml of deionized water and placed in an oven during 4 days (96 hours), as in Bodí et al. (2012). This procedure was repeated 5 times in order to observe the effects of wet-dry cycles in ash water repellency. The results showed significant differences

  10. Brittle-viscous deformation cycles in the dry lower continental crust

    NASA Astrophysics Data System (ADS)

    Menegon, Luca; Pennacchioni, Giorgio

    2015-04-01

    Many rheological models of the lithosphere (based on "strength envelopes") predict a weak aseismic lower crust below the strong brittle upper crust. An alternative view, based on the distribution of crustal seismicity, is that the lower crust could also be strong and seismic. It has been suggested that a strong, seismogenic lower crust results from the dry conditions of granulite facies rocks, which inhibit crystal plastic flow. This study investigates exhumed networks of shear zones from Nusfjord (Lofoten, northern Norway) to understand initiation and localization of viscous shearing in the dry lower crust. In the study area, different sets of ultramylonitic shear zones are hosted in the massive coarse-grained anorthosite. Metamorphic conditions of 720 °C, 0.9 GPa have been estimated for ductile deformation using amphibole-plagioclase geothermobarometry. Field evidence indicates that ductile shearing exploited pseudotachylyte veins and the associated damage zone of extensive fracturing. Undeformed pseudotachylyte veins locally overprint mylonitic pseudotachylytes suggesting that frictional melting occurred at the same metamorphic conditions of mylonitization. The deep crustal origin of the pseudotachylytes is also indicated by (1) the presence of microlites of labradoritic plagioclase and clinopyroxene, and of dendritic garnet, and (2) the recrystallization of clinopyroxene in the damage zone flanking the pseudotachylyte veins. Therefore the association of pseudotachylytes and mylonites records brittle-viscous deformation cycles under lower crustal conditions. The ultramylonites show phase mixing, fine grain size (5-20 μm) and equant shape of all minerals. Nucleation of amphibole in triple junctions and dilatant sites is common. EBSD analysis indicates that the minerals in the matrix are internally strain free and do not show a crystallographic preferred orientation. Taken together, these observations suggest that diffusion creep and grain boundary sliding were

  11. Effects of drying-wetting and freezing-thawing cycle on leachability of metallic elements in mine soils

    NASA Astrophysics Data System (ADS)

    Bang, H.; Kim, J.; Hyun, S.

    2016-12-01

    Mine leachate derived from contaminated mine sites with metallic elements can pose serious risks on human society and environment. Only labile fraction of metallic elements in mine soils is subject to leaching and movement by rainfall. Lability of metallic element in soil is a function of bond strengths between metal and soil surfaces, which is influenced by environmental condition (e.g., rainfall intensity, duration, temperature, etc.) The purpose of this study was to elucidate the effects of various climate conditions on the leaching patterns and lability of metallic elements in mine soils. To do this, two mine soils were sampled from two abandoned mine sites located in Korea. Leaching test were conducted using batch decant-refill method. Various climatic conditions were employed in leaching test such as (1) oven drying (40oC) - wetting cycles, (2) air drying (20oC) - wetting cycle, and (3) freezing (-40oC) - thawing cycles. Duration of drying and freezing were varied from 4 days to 2 weeks. Concentration of metallic elements, pH, Eh and concentration of dissolved iron and sulfate in leachate from each leaching process was measured. To identify the changes of labile fraction in mine soils after each of drying or freezing period, sequential extraction procedure (five fraction) was used to compare labile fraction (i.e., F1 + F2) of metallic elements. The concentration of metallic elements in mine leachate was increased after drying and freezing procedure. The amounts of released metallic element from mine soils was changed depending on their drying or freezing period. In addition, labile fraction of metallic elements in soil was also changed after drying and freezing. The changes in labile fraction after drying and freezing might be due to the increased soil surface area by pore water volume expansion. Further study is therefore needed to evaluate the impact of altered physical properties of soils such as hydration of soil surface area and shrinking by drying and

  12. Exploring African Aridification and Wet/dry Cycles Over the Last 3 MA

    NASA Astrophysics Data System (ADS)

    Meyers, C.; Tierney, J. E.; DeMenocal, P. B.

    2011-12-01

    Marine sediment records document a gradual increase in aeolian dust supply from Africa over the last 3 Ma in the Atlantic, Gulf of Aden, and Mediterranean (Larrasoaña et al., 2003, deMenocal 2004), with 'steps' in period and amplitude at ~2.8 Ma, ~1.7 Ma, and ~1.0 Ma. However, Mediterranean sapropel sequences document regular, precession-paced wet/dry cycles from changes in the strength of the African monsoon and Nile runoff since at least the Miocene (Rossignol-Strick, 1985, Krijgsman et al., 1995, Lourens et al., 1996). The influence of long-term drying trends in Africa on the movements and strength of the African monsoon over the late Pliocene and Pleistocene is not understood. We have constructed a biomarker-based African climate record by analyzing concentrations and δ D from long-chain, saturated fatty acid methyl esters (FAMEs) in eastern Mediterranean ODP Site 967 sediments from 2.8 - 3.1 Ma and 1.6 - 1.8 Ma. Long-chain fatty acids are produced in the leaf waxes of terrestrial plants (Eglinton and Hamilton, 1967) and are transported to marine sediments via aeolian and fluvial action. Sapropel sediments corresponding with precession minima and enhanced Nile River runoff (Rossignol-Strick, 1985) contain much higher concentrations of FAMEs than carbonate-rich sediments. Comparisons of the two intervals will be presented to illustrate changes in monsoon strength from 3 Ma to 1.6 Ma.

  13. Dry-cured ham tissue characterization by fast field cycling NMR relaxometry and quantitative magnetization transfer.

    PubMed

    Bajd, Franci; Gradišek, Anton; Apih, Tomaž; Serša, Igor

    2016-05-31

    Fast field cycling (FFC) and quantitative magnetization transfer (qMT) NMR methods are two powerful tools in NMR analysis of biological tissues. The qMT method is well established in biomedical NMR applications, while the FFC method is often used in investigations of molecular dynamics on which longitudinal NMR relaxation times of the investigated material critically depend. Despite their proven analytical potential, these two methods were rarely used in NMR studies of food, especially when combined together. In our study, we demonstrate the feasibility of a combined FFC/qMT-NMR approach for the fast and nondestructive characterization of dry-curing ham tissues differing by protein content. The characterization is based on quantifying the pure quadrupolar peak area (area under the quadrupolar contribution of dispersion curve obtained by FFC-NMR) and the restricted magnetization pool size (obtained by qMT-NMR). Both quantities correlate well with concentration of partially immobilized, nitrogen-containing and proton magnetization exchanging muscle proteins. Therefore, these two quantities could serve as potential markers for dry-curing process monitoring. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Dry/Wet Cycling and the Thermodynamics and Kinetics of Prebiotic Polymer Synthesis.

    PubMed

    Ross, David S; Deamer, David

    2016-07-26

    The endoergic nature of protein and nucleic acid assembly in aqueous media presents two questions that are fundamental to the understanding of life's origins: (i) how did the polymers arise in an aqueous prebiotic world; and (ii) once formed in some manner, how were they sufficiently persistent to engage in further chemistry. We propose here a quantitative resolution of these issues that evolved from recent accounts in which RNA-like polymers were produced in evaporation/rehydration cycles. The equilibrium Nm + Nn ↔ Nm+n + H₂O is endoergic by about 3.3 kcal/mol for polynucleotide formation, and the system thus lies far to the left in the starting solutions. Kinetic simulations of the evaporation showed that simple Le Châtelier's principle shifts were insufficient, but the introduction of oligomer-stabilizing factors of 5-10 kcal/mol both moved the process to the right and respectively boosted and retarded the elongation and hydrolysis rates. Molecular crowding and excluded volume effects in present-day cells yield stabilizing factors of that order, and we argue here that the crowded conditions in the evaporites generate similar effects. Oligomer formation is thus energetically preferred in those settings, but the process is thwarted in each evaporation step as diffusion becomes rate limiting. Rehydration dissipates disordered oligomer clusters in the evaporites, however, and subsequent dry/wet cycling accordingly "ratchets up" the system to an ultimate population of kinetically trappedthermodynamically preferred biopolymers.

  15. Dry/Wet Cycling and the Thermodynamics and Kinetics of Prebiotic Polymer Synthesis

    PubMed Central

    Ross, David S.; Deamer, David

    2016-01-01

    The endoergic nature of protein and nucleic acid assembly in aqueous media presents two questions that are fundamental to the understanding of life’s origins: (i) how did the polymers arise in an aqueous prebiotic world; and (ii) once formed in some manner, how were they sufficiently persistent to engage in further chemistry. We propose here a quantitative resolution of these issues that evolved from recent accounts in which RNA-like polymers were produced in evaporation/rehydration cycles. The equilibrium Nm + Nn ↔ Nm+n + H2O is endoergic by about 3.3 kcal/mol for polynucleotide formation, and the system thus lies far to the left in the starting solutions. Kinetic simulations of the evaporation showed that simple Le Châtelier’s principle shifts were insufficient, but the introduction of oligomer-stabilizing factors of 5–10 kcal/mol both moved the process to the right and respectively boosted and retarded the elongation and hydrolysis rates. Molecular crowding and excluded volume effects in present-day cells yield stabilizing factors of that order, and we argue here that the crowded conditions in the evaporites generate similar effects. Oligomer formation is thus energetically preferred in those settings, but the process is thwarted in each evaporation step as diffusion becomes rate limiting. Rehydration dissipates disordered oligomer clusters in the evaporites, however, and subsequent dry/wet cycling accordingly “ratchets up” the system to an ultimate population of kinetically trappedthermodynamically preferred biopolymers. PMID:27472365

  16. Impact of Drying and Rewetting on Carbon Cycling in a Northern fen

    NASA Astrophysics Data System (ADS)

    Estop, C.; Blodau, C.

    2009-05-01

    Peatlands are quantitatively important carbon-storing terrestrial ecosystems where peat develops due to the rate of C input (organic matter as litter) surpassing that of C output (gas efflux and leaching) during biomass decomposition. High water contents are an important factor controlling such equilibrium in these soils since water does not become limiting for plant growth while keeping peat in a highly reduced state and thus lowering peat degradation rate. A predicted effect of current climate change is the potential alteration in the hydrological regime due to extreme rain events and extended dry periods. Thus, greater fluctuations in the water table levels may be expected to influence redox processes and carbon cycling in peatlands. We investigated respiration and transport processes in peat during manipulation of water table level at ecosystem scale in a small iron-rich fen located in a forested area of North Bavaria (Germany). The experimental design consists of three treatment (dry-rewetting) and three control plots where spatially high resolved peat profiles (2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20, 25, 30, 45 and 55 cm depth) were weekly followed up for 7 months. An approach combining gas (for CO2, CH4 and O2 analysis) and pore-water sampling allowed gaining insight into spatio-temporal gradients and linking those to water table fluctuations. Soil moisture, temperature and CO2 concentrations were also investigated by installing sensors in the upper peat layer to obtain data series during the investigated period. A seasonal drying event naturally occurred in the control plots during summer. The drying effect was thus reinforced in intensity and duration in the treatment plots. The main terminal electron accepting process was Fe(III)-reduction as suggested by high reduced iron and nearly undetected hydrogen sulphide concentrations. Water table manipulation affected peat redox processes with progressive suppression of Fe(III)-reduction during the drying period

  17. Rainfall and wet and dry cycle's impact on ash thickness. A laboratory experiment

    NASA Astrophysics Data System (ADS)

    Pereira, Paulo; Keestra, Saskia; Peters, Piet; Cerdà, Artemi

    2016-04-01

    Ash is the most important and effective soil protection in the immediate period after the fire (Cerda and Doerr, 2008; Pereira et al., 2015a). This protection can last for days or weeks depending on the fire severity, topography of the burned area and post-fire meteorological conditions. In the initial period after the fire, ash is easily transported by wind. However after the first rainfalls, ash is eroded, or bind in soil surface (Pereira et al., 2013, 2015a). Ash thickness has implications on soil protection. The soil protection against the erosion and the ash capacity to retain water increases with the ash thickness (Bodi et al., 2014). Ash cover is very important after fire because store water and releases into soil a large amount of nutrients, fundamental to vegetation recuperation (Pereira et al., 2014). Despite the importance of ash thickness in post fire environments, little information is available about the effects of rainfall and wet and dry cycle's effects on ash thickness. This work aims to fill this gap. The objective of this study is to investigate the impacts of rainfall and wet and dry cycles in the ash thickness of two different under laboratory conditions. Litter from Oak (Quercus robur) and Spruce (Picea abis) were collected to and exposed during 2 hours to produce ash at 200 and 400 C. Subsequently a layer of 15 mm ash was spread on soil surface in small boxes (24x32 cm) and then subjected to rainfall simulation. Boxes were placed at a 17% of inclination and a rainfall intensity of 55 mm/h during 40 minutes was applied. After the rainfall simulation the plots were stored in an Oven at the temperature of 25 C during four days, in order to identify the effects of wet and dry cycles (Bodi et al., 2013). Ash thickness was measured after the first rainfall (AFR), before the second rainfall (BSR) - after the dry period of 4 days - and after the second rainfall (ASR). In each box a grid with 57 points was designed in order to analyse ash thickness

  18. Effects of repeated wet/dry cycling on the structure and performance of sulfonated pentablock copolymer membranes

    NASA Astrophysics Data System (ADS)

    Truong, Phuc; Stein, Gila

    Sulfonated block copolymers have shown potential as membranes for water purification. However, the performance of these materials under cyclic wet/dry conditions is not well understood. We measured the membrane structure, mechanical properties, and water vapor transport rates in a sulfonated pentablock copolymer as a function of the number of wet/dry cycles. The polymer is synthesized with an ABCBA block sequence, where A is poly(t-butyl styrene), B is poly(hydrogenated isoprene), and C is poly(styrene sulfonate). The ion exchange capacity is 2 meq, and membranes were prepared by coating from a solution. Using small angle X-ray scattering, we find the structure in as-prepared membranes resembles disordered micelles, and the characteristic length scale swells slightly with each wet/dry cycle. This lattice swelling is likely constrained by the glassy end-blocks. We also detect a lower yield point and less overall tensile strength with repeated cycling. Water vapor transport rates vary with the number of wet/dry cycle, however no specific trend was observed.

  19. Effect of wet-dry cycling on the decay properties of aspen fiber high-density polypropylene composites.

    Treesearch

    Rebecca E. Ibach; Roger M. Rowell; Sandra E. Lange; Rebecca L. Schumann

    2002-01-01

    Aspen fiber-polypropylene composites were prepared with various levels of fiber (0,30%, 40%, 50%, and 60%), polypropylene (PP) (100%, 98%, 70%, 68%, 60%, 58%, 50%, 48%, 40%, and 38%), and the compatibilizer maleated polypropylene (MAPP) (0 and 2%). Specimens were either subjected to 10 cycles of 1 week room temperature water soaking-oven drying or 2-hr. boiling...

  20. Effect of incubation temperature and wet-dry cycle on the availabilities of Cd, Pb and Zn in soil.

    PubMed

    Si, Ji-tao; Tian, Bao-guo; Wang, Hong-tao

    2006-01-01

    The effect of incubation temperature and wet-dry cycle on the availabilities of Cd, Pb and Zn was studied. Three soils with pH ranging from 3.8 to 7.3, organic carbon (OC) from 0.7% to 2.4%, and clay from 12.3% to 35.6% were selected. Soils were spiked with reagent grade Cd(NO3)2, Pb(NO3)2, and Zn(NO3)2 at concentrations of 30 mg Cd/kg soil, 300 mg Zn/kg soil and 2000 mg Pb/kg soil. The soils were incubated at 35, 60, 105 degrees C, respectively and went through four wet-dry cycles. Metal availability in soils was estimated by soil extraction with 0.1 mol/L Ca(NO3)2. According to this study, the effect of the spiking temperature on the metal availabilities was different among the metals, soils and wet-dry cycles. Mostly, 35 degrees C was the first recommended spiking temperature for Cd and Pb while no spiking temperature was obviously better than others for Zn. Three wet-dry cycles was recommended regardless of the type of metals and incubation temperature.

  1. Contact lens drying and visual performance: the vision cycle with contact lenses.

    PubMed

    Thai, Lee Choon; Tomlinson, Alan; Ridder, William H

    2002-06-01

    The purpose of this study was to measure the effect of precontact lens tear film break-up on visual performance. Four asymptomatic soft contact lens wearers had contrast sensitivity measured by a temporal, two-alternative, force choice paradigm combined with a self-paced methods of limits. Stimuli were vertically orientated sine wave gratings (0.5 to 14 cycles per degree [cpd] presented for 16.67 ms. Contrast sensitivity was measured before precontact lens tear break-up by a stimuli presented 2 s after the blink. A post-tear layer break-up measurement taken with the stimuli presented after break-up had been observed by the use of a video camera attached to a Tearscope. Contrast sensitivity was found to be reduced following precontact lens tear film break-up for stimuli of 4, 6, and 10 cpd; the data approached significance at 14 cpd. Further reductions in contrast sensitivity were observed for one subject when measurements were continued for 4 s following break-up. Contrast sensitivity is significantly reduced for middle to high spatial frequencies when the precontact lens tear film dries and breaks up. The combination of observations of visual performance immediately following the blink (from earlier experiments) and measurements following tear film break-up in this experiment allows description of a "vision cycle" for contact lens wearers in the interval between blinks. It is suggested that break-up of the precontact lens tear film could account for the complaints of intermittent blurred vision in some contact lens wearers and may provide a stimulus to blinking in these individuals.

  2. Life cycle assessment of fuel ethanol derived from corn grain via dry milling.

    PubMed

    Kim, Seungdo; Dale, Bruce E

    2008-08-01

    Life cycle analysis enables to investigate environmental performance of fuel ethanol used in an E10 fueled compact passenger vehicle. Ethanol is derived from corn grain via dry milling. This type of analysis is an important component for identifying practices that will help to ensure that a renewable fuel, such as ethanol, may be produced in a sustainable manner. Based on data from eight counties in seven Corn Belt states as corn farming sites, we show ethanol derived from corn grain as E10 fuel would reduce nonrenewable energy and greenhouse gas emissions, but would increase acidification, eutrophication and photochemical smog, compared to using gasoline as liquid fuel. The ethanol fuel systems considered in this study offer economic benefits, namely more money returned to society than the investment for producing ethanol. The environmental performance of ethanol fuel system varies significantly with corn farming sites because of different crop management practices, soil properties, and climatic conditions. The dominant factor determining most environmental impacts considered here (i.e., greenhouse gas emissions, acidification, eutrophication, and photochemical smog formation) is soil related nitrogen losses (e.g., N2O, NOx, and NO3-). The sources of soil nitrogen include nitrogen fertilizer, crop residues, and air deposition. Nitrogen fertilizer is probably the primary source. Simulations using an agro-ecosystem model predict that planting winter cover crops would reduce soil nitrogen losses and increase soil organic carbon levels, thereby greatly improving the environmental performance of the ethanol fuel system.

  3. Weathering of expansive sedimentary rock due to cycles of wetting and drying

    SciTech Connect

    Day, R.W. )

    1994-09-01

    There are several different mechanisms by which sedimentary rock can weather, such as: (1) Rebound: for cut areas, where the overburden has been removed by erosion or during mass-grading operations, the sedimentary rock will rebound due to the release in overburden pressure, the rebound can cause the opening or widening of cracks and joints; (2) Physical Weathering: sedimentary rock can be broken apart by the physical growth of plant roots or by the freezing of water in rock cracks or joints. Studies have also shown that precipitation of gypsum in rock pores, cracks, and joints can cause rock expansion and disintegration. Such conditions occur in arid climates where subsurface moisture evaporates at ground surface, precipitating the minerals in the rock pores. Acicular gypsum crystals have been observed to grow perpendicular to structures and are believed to exert the most force at their growing end (Hawkins and Pinces, 1987). Acicular gypsum growth has even been observed in massive sandstone, which resulted in significant heave (Hollingsworth and Grover, 1992); (3) Chemical Weathering: weathering of sedimentary rock can be due to oxidation, hydration of clay minerals, and the chemical alteration of the silt-size particles to clay. Factors affecting oxidation include the presence of moisture and oxygen (aerobic conditions), biological activity, acidic environment, and temperature (Hollingsworth and Grover, 1992). The purpose of this study was to investigate the weathering of expansive sedimentary rock due to cycles of wetting and drying at temperatures representative of field conditions.

  4. An Invasive Grass Species Alters Carbon Cycling in Hawaiian Dry Forest

    NASA Astrophysics Data System (ADS)

    Litton, C. M.; Sandquist, D. R.; Cordell, S.

    2004-12-01

    At lower elevations on the leeward side of the island of Hawaii, remnant native forests are heavily invaded by an introduced African bunchgrass, Pennisetum setaceum (fountain grass). Our research is designed to determine the consequences of this invasion for carbon (C) cycling in Hawaiian dry forests. We examined above- and belowground C pools and fluxes in 400 m2 replicated forest plots (n = 4) with fountain grass (grass plots) and in areas where fountain grass had been removed for ˜3 years (removal plots). C pools were estimated with direct sampling and allometric equations developed in situ for the dominant tree species. Aboveground net primary productivity (ANPP) was estimated as aboveground biomass increment plus litterfall minus loss from mortality (trees) and with clip plots (grass and herbaceous species); total belowground carbon allocation (TBCA) was estimated using a conservation of mass, C balance approach. Our results indicate that the invasion of a non-native grass in this ecosystem has considerable impacts on both C pools and fluxes. Aboveground, tree biomass did not differ between treatments (P = 0.57) but the presence of fountain grass led to a 7.5-fold increase in understory biomass in grass plots compared to removal plots (P < 0.01). Tree ANPP was significantly higher in removal plots for both foliage (0.10 and 0.06 kg C m-2 yr-1 for removal and grass plots, respectively; P = 0.02) and wood (0.13 and 0.05 kg C m-2 yr-1 for removal and grass plots, respectively; P < 0.01). However, grass ANPP was ˜35% greater than tree foliage productivity in grass plots. Despite this added foliar productivity, total ANPP (Tree + Grass ANPP) was significantly higher in removal plots (P = 0.04). Belowground, grass plots exhibited higher rates of soil-surface CO2 efflux (1.09 and 1.38 kg C m-2 yr-1 for removal and grass plots, respectively; P = 0.03 ). Likewise, TBCA was significantly higher in grass plots (1.21 kg C m-2 yr-1) than in removal plots (0.97 kg C m-2

  5. Mössbauer study of the corrosion behaviour of pure iron and weathering steel under a wet-dry cycle

    NASA Astrophysics Data System (ADS)

    Marco, J. F.; Dávalos, J.; Gancedo, J. R.; Gracia, M.

    1989-03-01

    Mossbauer spectroscopy (MBS) and X-ray diffraction (XRD) have been used to establish the composition of the rust layer formed on weathering steel and pure iron under several wet-dry cycles in a SO2-polluted atmosphere. FeSO3-3H2O, FeSO4-4H2O, and poorly crystalline ferrihydrite were identified as the only corrosion products. The Mossbauer spectrum of FeSO3-3H2O is reported.

  6. Use of manometric temperature measurement (MTM) and SMART freeze dryer technology for development of an optimized freeze-drying cycle.

    PubMed

    Gieseler, Henning; Kramer, Tony; Pikal, Michael J

    2007-12-01

    This report provides, for the first time, a summary of experiments using SMART Freeze Dryer technology during a 9 month testing period. A minimum ice sublimation area of about 300 cm(2) for the laboratory freeze dryer, with a chamber volume 107.5 L, was found consistent with data obtained during previous experiments with a smaller freeze dryer (52 L). Good reproducibility was found for cycle design with different type of excipients, formulations, and vials used. SMART primary drying end point estimates were accurate in the majority of the experiments, but showed an over prediction of primary cycle time when the product did not fully achieve steady state conditions before the first MTM measurement was performed. Product resistance data for 5% sucrose mixtures at varying fill depths were very reproducible. Product temperature determined by SMART was typically in good agreement with thermocouple data through about 50% of primary drying time, with significant deviations occurring near the end of primary drying, as expected, but showing a bias much earlier in primary drying for high solid content formulations (16.6% Pfizer product) and polyvinylpyrrolidone (40 kDa) likely due to water "re-adsorption" by the amorphous product during the MTM test. (c) 2007 Wiley-Liss, Inc.

  7. Fast freeze-drying cycle design and optimization using a PAT based on the measurement of product temperature.

    PubMed

    Bosca, Serena; Barresi, Antonello A; Fissore, Davide

    2013-10-01

    This paper is focused on the use of an innovative Process Analytical Technology for the fast design and optimization of freeze-drying cycles for pharmaceuticals. The tool is based on a soft-sensor, a device that uses the experimental measure of product temperature during freeze-drying, a mathematical model of the process, and the Extended Kalman Filter algorithm to estimate the sublimation flux, the residual amount of ice in the vial, and some model parameters (heat and mass transfer coefficients). The accuracy of the estimations provided by the soft-sensor has been shown using as test case aqueous solutions containing different excipients (sucrose, polyvinylpyrrolidone), processed at various operating conditions, pointing out that the soft-sensor allows a fast estimation of model parameters and product dynamics without involving expensive hardware or time consuming analysis. The possibility of using the soft-sensor to calculate in-line (or off-line) the design space of the primary drying phase is here presented and discussed. Results evidences that by this way, it is possible to identify the values of the heating fluid temperature that maintain product temperature below the limit value, as well as the operating conditions that maximize the sublimation flux. Various experiments have been carried out to test the effectiveness of the proposed approach for a fast design of the cycle, evidencing that drying time can be significantly reduced, without impairing product quality.

  8. Life Cycle Cost of Solar Biomass Hybrid Dryer Systems for Cashew Drying of Nuts in India

    NASA Astrophysics Data System (ADS)

    Dhanushkodi, Saravanan; Wilson, Vincent H.; Sudhakar, Kumarasamy

    2015-12-01

    Cashew nut farming in India is mostly carried out in small and marginal holdings. Energy consumption in the small scale cashew nut processing industry is very high and is mainly due to the high energy consumption of the drying process. The drying operation provides a lot of scope for energy saving and substitutions of other renewable energy sources. Renewable energy-based drying systems with loading capacity of 40 kg were proposed for application in small scale cashew nut processing industries. The main objective of this work is to perform economic feasibility of substituting solar, biomass and hybrid dryer in place of conventional steam drying for cashew drying. Four economic indicators were used to assess the feasibility of three renewable based drying technologies. The payback time was 1.58 yr. for solar, 1.32 for biomass and 1.99 for the hybrid drying system, whereas as the cost-benefit estimates were 5.23 for solar, 4.15 for biomass and 3.32 for the hybrid system. It was found that it is of paramount importance to develop solar biomass hybrid dryer for small scale processing industries.

  9. Microstructure Evolution from X-CT Measurements for Concrete/mortar under Multi-actions of Composite Salts Dry-wet Cycles and Loading

    NASA Astrophysics Data System (ADS)

    Chen, Yanjuan; Gao, Jianming; Shen, Daman

    2017-08-01

    Inthis research, microstructure evolution forconcrete/mortar under multi-actions of composite salts dry-wet cycles and loading was investigated through X-CT measurements. The evolution process of pores and micro-cracking with the erosion time were tracked. Compared the different erosion actions, it was found that dry-wet cycles promoted the pores become connected gradually. Besides, the dry-wet cycles accelerated the damage seriously on interface area between concrete and aggregate, whistle, loading contributes to the cracking propagation toward the internal. Moreover, fly ash played a positive role in the increasing of the number of harmless holes again and contributed to the durability of concrete.

  10. Rapid freeze-drying cycle optimization using computer programs developed based on heat and mass transfer models and facilitated by tunable diode laser absorption spectroscopy (TDLAS).

    PubMed

    Kuu, Wei Y; Nail, Steven L

    2009-09-01

    Computer programs in FORTRAN were developed to rapidly determine the optimal shelf temperature, T(f), and chamber pressure, P(c), to achieve the shortest primary drying time. The constraint for the optimization is to ensure that the product temperature profile, T(b), is below the target temperature, T(target). Five percent mannitol was chosen as the model formulation. After obtaining the optimal sets of T(f) and P(c), each cycle was assigned with a cycle rank number in terms of the length of drying time. Further optimization was achieved by dividing the drying time into a series of ramping steps for T(f), in a cascading manner (termed the cascading T(f) cycle), to further shorten the cycle time. For the purpose of demonstrating the validity of the optimized T(f) and P(c), four cycles with different predicted lengths of drying time, along with the cascading T(f) cycle, were chosen for experimental cycle runs. Tunable diode laser absorption spectroscopy (TDLAS) was used to continuously measure the sublimation rate. As predicted, maximum product temperatures were controlled slightly below the target temperature of -25 degrees C, and the cascading T(f)-ramping cycle is the most efficient cycle design. In addition, the experimental cycle rank order closely matches with that determined by modeling.

  11. Abundance, Distribution and Cycling of Organic Carbon and Nitrogen in University Valley (McMurdo Dry Valleys of Antarctica) Permafrost Soils with Differing Ground Thermal and Moisture Conditions: Analogue to C-N Cycle on Mars

    NASA Astrophysics Data System (ADS)

    Faucher, B. F.; Lacelle, D. L.; Davila, A. D.; Pollard, W. P.; McKay, C. P. M.

    2016-05-01

    High elevation McMurdo Dry Valleys of Antarctica are key Mars analogue sites. Our investigation focuses on the link between ground ice origin, distribution and cycling of organic carbon and nitrogen in University Valley, and its soil habitability.

  12. Three Gorges Dam alters the Changjiang (Yangtze) river water cycle in the dry seasons: Evidence from H-O isotopes.

    PubMed

    Deng, Kai; Yang, Shouye; Lian, Ergang; Li, Chao; Yang, Chengfan; Wei, Hailun

    2016-08-15

    As the largest hydropower project in the world, the Three Gorges Dam (TGD) has attracted great concerns in terms of its impact on the Changjiang (Yangtze) River and coastal marine environments. In this study, we measured or collected the H-O isotopic data of river water, groundwater and precipitation in the mid-lower Changjiang catchment during the dry seasons of recent years. The aim was to investigate the changes of river water cycle in response to the impoundment of the TGD. Isotopic evidences suggested that the mid-lower Changjiang river water was ultimately derived from precipitation, but dominated by the mixing of different water masses with variable sources and isotopic signals as well. The isotopic parameter "deuterium excess" (d-excess) yielded large fluctuations along the mid-lower mainstream during the initial stage of the TGD impoundment, which was inherited from the upstream water with inhomogeneous isotopic signals. However, as the reservoir water level rising to the present stage, small variability of d-excess was observed along the mid-lower mainstream. This discrepancy could be explained that the TGD impoundment had significantly altered the water cycle downstream the dam, with the rising water level increasing the residence time and enhancing the mixing of reservoir water derived from upstream. This eventually resulted in the homogenization of reservoir water, and thus small fluctuations of d-excess downstream the dam after the quasi-normal stage (2008 to present). We infer that the retention effect of large reservoirs has greatly buffered the d-excess natural variability of water cycle in large river systems. Nevertheless, more research attention has to be paid to the damming effect on the water cycle in the river, estuarine and coastal areas, especially during the dry seasons.

  13. A comparative life cycle assessment of conventional hand dryer and roll paper towel as hand drying methods.

    PubMed

    Joseph, Tijo; Baah, Kelly; Jahanfar, Ali; Dubey, Brajesh

    2015-05-15

    A comparative life cycle assessment, under a cradle to gate scope, was carried out between two hand drying methods namely conventional hand dryer use and dispenser issued roll paper towel use. The inventory analysis for this study was aided by the deconstruction of a hand dryer and dispenser unit besides additional data provided by the Physical Resources department, from the product system manufacturers and information from literature. The LCA software SimaPro, supported by the ecoinvent and US-EI databases, was used towards establishing the environmental impacts associated with the lifecycle stages of both the compared product systems. The Impact 2002+ method was used for classification and characterization of these environmental impacts. An uncertainty analysis addressing key input data and assumptions made, a sensitivity analysis covering the use intensity of the product systems and a scenario analysis looking at a US based use phase for the hand dryer were also conducted. Per functional unit, which is to achieve a pair of dried hands, the dispenser product system has a greater life cycle impact than the dryer product system across three of four endpoint impact categories. The use group of lifecycle stages for the dispenser product system, which represents the cradle to gate lifecycle stages associated with the paper towels, constitutes the major portion of this impact. For the dryer product system, the use group of lifecycle stages, which essentially covers the electricity consumption during dryer operation, constitutes the major stake in the impact categories. It is evident from the results of this study that per dry, for a use phase supplied by Ontario's grid (2010 grid mix scenario) and a United States based manufacturing scenario, the use of a conventional hand dryer (rated at 1800 W and under a 30s use intensity) has a lesser environmental impact than with using two paper towels (100% recycled content, unbleached and weighing 4 g) issued from a roll

  14. Nitrogen supply modulates the effect of changes in drying-rewetting frequency on soil C and N cycling and greenhouse gas exchange.

    PubMed

    Morillas, Lourdes; Durán, Jorge; Rodríguez, Alexandra; Roales, Javier; Gallardo, Antonio; Lovett, Gary M; Groffman, Peter M

    2015-10-01

    Climate change and atmospheric nitrogen (N) deposition are two of the most important global change drivers. However, the interactions of these drivers have not been well studied. We aimed to assess how the combined effect of soil N additions and more frequent soil drying-rewetting events affects carbon (C) and N cycling, soil:atmosphere greenhouse gas (GHG) exchange, and functional microbial diversity. We manipulated the frequency of soil drying-rewetting events in soils from ambient and N-treated plots in a temperate forest and calculated the Orwin & Wardle Resistance index to compare the response of the different treatments. Increases in drying-rewetting cycles led to reductions in soil NO3- levels, potential net nitrification rate, and soil : atmosphere GHG exchange, and increases in NH4+ and total soil inorganic N levels. N-treated soils were more resistant to changes in the frequency of drying-rewetting cycles, and this resistance was stronger for C- than for N-related variables. Both the long-term N addition and the drying-rewetting treatment altered the functionality of the soil microbial population and its functional diversity. Our results suggest that increasing the frequency of drying-rewetting cycles can affect the ability of soil to cycle C and N and soil : atmosphere GHG exchange and that the response to this increase is modulated by soil N enrichment.

  15. Impact of repeated dry-wet cycles on soil greenhouse gas emissions, extracellular enzyme activity and nutrient cycling in a temperate forest

    NASA Astrophysics Data System (ADS)

    Leitner, Sonja; Zimmermann, Michael; Bockholt, Jan; Schartner, Markus; Brugner, Paul; Holtermann, Christian; Zechmeister-Boltenstern, Sophie

    2014-05-01

    Climate change research predicts that both frequency and intensity of weather extremes such as long drought periods and heavy rainfall events will increase in mid Europe over the next decades. Soil moisture is one of the major factors controlling microbial soil processes, and it has been widely agreed that feedback effects between altered precipitation and changed soil fluxes of the greenhouse gases CO2, CH4 and N2O could intensify climate change. In a field experiment in an Austrian beech forest, we established a precipitation manipulation experiment, which will be conducted for 3 years. We use roofs to exclude rainfall from reaching the forest soil and simulate drought periods, and a sprinkler system to simulate heavy rainfall events. We applied repeated dry-wet cycles in two intensities: one treatment received 6 cycles of 1 month drought followed by 75mm irrigation within 2 hours, and a parallel treatment received 3 cycles of 2 months drought followed by 150mm irrigation within 3 hours. We took soil samples 1 day before, 1 day after and 1 week after rewetting events and analyzed them for soil nutrients and extracellular enzyme activities. Soil fluxes of CO2, N2O and CH4 were constantly monitored with an automated flux chamber system, and environmental parameters were recorded via dataloggers. In addition, we determined fluxes and nutrient concentrations of bulk precipitation, throughfall, stemflow, litter percolate and soil water. Next we plan to analyze soil microbial community composition via PLFAs to investigate microbial stress resistance and resilience, and we will use ultrasonication to measure soil aggregate stability and protection of soil organic matter in stressed and control plots. The results of the first year show that experimental rainfall manipulation has influenced soil extracellular enzymes. Potential phenoloxidase activity was significantly reduced in stressed treatments compared to control plots. All measured hydrolytic enzymes (cellulase

  16. [Effects of different iron oxides on methane emission in paddy soil as related to drying/wetting cycles].

    PubMed

    Zhang, Tian-Jiao; Tang, Jia; Zhuang, Li; Xiong, Ge-Sheng; Liu, Zhi; Zhou, Shun-Gui

    2014-03-01

    This study investigated the effects of iron oxides with different crystallinities, ferrihydrite (SF) and hematite (SH), on the methane emission in paddy soil of South China under different water conditions, alternative drying/wetting cycles (DW) and continuous flooding (CF). The rates of methane emission, methane production potential and concentrations of Fe(II) and Fe(III) were determined. Results showed that compared with CF, the average methane emission rate was greatly inhibited by DW over 61%, and the addition of iron oxides reduced methane emission rates by 53%. Under the circumstance of DW and iron oxides addition, the combined inhibition effect on the average methane emission (65%-94%) and methane production potential (57%-93%) was significantly higher than the single effect caused by DW or iron oxides. Interestingly, DW coupling poorly crystalline ferrihydrite (SF-DW, 94%) posed a more significantly inhibitory effect on the methane emission than coupling crystalline hematite (SH-DW, 65%). Statistical analysis showed that there was a significantly negative correlation between the Fe(III) concentrations and the methane emission rates (R2 = -0.98, P < 0.01). Experimental results showed that DW facilitated the cyclic regeneration of Fe(III), and the Fe(III)/Fe(II) cycle in poorly crystalline ferrihydrite was more susceptible to DW than hematite. This study suggested that alternative drying/wetting cycles can remarkably enhance the inhibitory effect of iron oxides on methane emission from paddy soil, and the coupled suppression effect of DW and poorly crystalline ferrihydrite is more obvious than the coupled effect of DW and crystalline hematite.

  17. Halogens in the Dry Valleys Lakes, Antarctica: dynamic cycling between water, sediment, and cryogenic evaporites

    NASA Astrophysics Data System (ADS)

    Snyder, G. T.; Dowling, C. B.; Harbert, A.; Lu, H.; Lyons, W. B.; Welch, K. A.

    2006-12-01

    Many of the McMurdo Dry Valleys lakes of Antarctica exhibit saline to hypersaline bottom waters whose chemistry is distinct from that of sea water. The source and relative abundance of dissolved Cl, Br, and I in these unusual waters has been modified by several potential processes including: seawater incursions, water- rock interactions, microbial scavenging, glacial melting and precipitation, and atmospheric deposition. Since all of these processes are affected by both long-term and short-term climate change, lake waters and the salts that are deposited around them provide sensitive indicators of lake dessication and refilling in the past. We present elemental analyses, not only of the lake water, but also of bottom sediments and cryogenic evaporites recovered from the Dry Valleys. XRD analyses indicate that gypsum and antarcticite are precipitated around saline lakes presently situated more than 40 km from the ocean (Vanda, Don Juan, Joyce), while mirabilite is found near small pools in the Garwood Valley, only a few km from the ocean. Lake water enrichments in Ca and Cl, relative to Na suggest that either dissolution of gypsum and antarcticite has occurred in Don Juan Pond and Lake Vanda, or that these two small bodies of water previously lost sodium to mirabilite formation. Lakes Fryxell and Joyce, as well as waters in Garwood Valley show near-sea water ratios. Dissolved iodine, and to a lesser extent bromine, are commonly associated with diagenesis of marine organic matter in regions of high productivity, so it is surprising that the Dry Valleys lake waters are enriched in these two elements. These enrichments are also apparent in pore fluids of shallow sediments on the lake bottoms. In addition, the sediments themselves are highly enriched in iodine in the upper 5 cm (up to 77 ppm). This is likely due to remobilization of dissolved iodide, which is mobile in reduced form, but becomes fixed as adsorbed or organic iodine upon diffusing into shallow oxic

  18. Effects of Soil Warming and Drying on Methane Cycling in Northern Peatlands

    NASA Astrophysics Data System (ADS)

    White, J. R.; Shannon, R. D.; Bridgham, S. D.

    2007-12-01

    Boreal peatlands contain a large portion of the earth's terrestrial organic carbon and may be particularly vulnerable to changes in climate. Temperature conditions in boreal regions are predicted to increase during the twenty-first century which may accelerate changes in soil microbial processes and plant community dynamics. Climate-driven changes in plant community composition might affect the pathways and rates of methanogenesis, the plant-mediated emission of methane and the scavenging of methane by methanotrophic bacteria. Climate change may also affect nutrient availability and cycling that indirectly affect methane cycling. To date, these feedbacks have not been incorporated into the carbon cycling components of climate models. We investigated the effects of soil warming and water-table manipulations on methane cycling in a field mesocosm experiment in northern Minnesota, USA. Large intact soil monoliths removed from a bog and fen received infrared warming treatments crossed with water-table treatments for six years. In years 5 and 6, concentrations, fluxes and isotopic compositions of methane were measured along with acetate, sulfate, ammonium, belowground net primary productivity and changes in N retention. Methane cycling is affected by changes in N availability associated with soil decomposition and through increased root productivity. An expansion of the rhizosphere of woody shrubs in bogs during the initial 4 yrs was associated with greater methane emission rates. We speculate that an increase in labile substrates associated with root exudates and enhanced plant transport may be factors contributing to the increase in methane emissions. Stable isotopic data from porewater support acetate fermentation as the principal pathway of methanogenesis in bog plots (mean ä13CH4 = -39.3 °). Under warm, wet conditions, the majority of the methane was isotopically heavy (mean ä13CH4 = -28.1 °), suggesting a predominance of methanotrophic activity throughout the

  19. Isotopic composition of Antarctic Dry Valley nitrate: Implications for NOy sources and cycling in Antarctica

    USGS Publications Warehouse

    Michalski, G.; Bockheim, James G.; Kendall, C.; Thiemens, M.

    2005-01-01

    Nitrates minerals from the Dry Valleys of Antarctica have been analyzed for their oxygen and nitrogen isotopic compositions. The 15N was depleted with δ15N values ranging from −9.5 to −26.2‰, whereas the 17O and 18O isotopes were highly enriched (with excess 17O) with δ18O values spanning 62–76‰ and Δ17O values from 28.9 to 32.7‰. These are the largest 17O enrichments observed in any known mineral. The oxygen isotopes indicate that nitrate is from a combination of tropospheric transport of photochemically produced HNO3 and HNO3 formed in the stratosphere.

  20. The Effect of Limited Diffusion and Wet–Dry Cycling on Reversible Polymerization Reactions: Implications for Prebiotic Synthesis of Nucleic Acids

    PubMed Central

    Higgs, Paul G.

    2016-01-01

    A long-standing problem for the origins of life is that polymerization of many biopolymers, including nucleic acids and peptides, is thermodynamically unfavourable in aqueous solution. If bond making and breaking is reversible, monomers and very short oligomers predominate. Recent experiments have shown that wetting and drying cycles can overcome this problem and drive the formation of longer polymers. In the dry phase, bond formation is favourable, but diffusion is restricted, and bonds only form between monomers that are initially close together. In the wet phase, some of the bonds are hydrolyzed. However, repositioning of the molecules allows new bonds to form in the next dry phase, leading to an increase in mean polymer length. Here, we consider a simple theoretical model that explains the effect of cycling. There is an equilibrium length distribution with a high mean length that could be achieved if diffusion occurred freely in the dry phase. This equilibrium is inaccessible without diffusion. A single dry cycle without diffusion leads to mean lengths much shorter than this. Repeated cycling leads to a significant increase in polymerization relative to a single cycle. In the most favourable case, cycling leads to the same equilibrium length distribution as would be achieved if free diffusion were possible in the dry phase. These results support the RNA World scenario by explaining a potential route to synthesis of long RNAs; however, they also imply that cycling would be beneficial to the synthesis of other kinds of polymers, including peptides, where bond formation involves a condensation reaction. PMID:27338479

  1. Modeling the grazing effect on dry grassland carbon cycling with modified Biome-BGC grazing model

    NASA Astrophysics Data System (ADS)

    Luo, Geping; Han, Qifei; Li, Chaofan; Yang, Liao

    2014-05-01

    Identifying the factors that determine the carbon source/sink strength of ecosystems is important for reducing uncertainty in the global carbon cycle. Arid grassland ecosystems are a widely distributed biome type in Xinjiang, Northwest China, covering approximately one-fourth the country's land surface. These grasslands are the habitat for many endemic and rare plant and animal species and are also used as pastoral land for livestock. Using the modified Biome-BGC grazing model, we modeled carbon dynamics in Xinjiang for grasslands that varied in grazing intensity. In general, this regional simulation estimated that the grassland ecosystems in Xinjiang acted as a net carbon source, with a value of 0.38 Pg C over the period 1979-2007. There were significant effects of grazing on carbon dynamics. An over-compensatory effect in net primary productivity (NPP) and vegetation carbon (C) stock was observed when grazing intensity was lower than 0.40 head/ha. Grazing resulted in a net carbon source of 23.45 g C m-2 yr-1, which equaled 0.37 Pg in Xinjiang in the last 29 years. In general, grazing decreased vegetation C stock, while an increasing trend was observed with low grazing intensity. The soil C increased significantly (17%) with long-term grazing, while the soil C stock exhibited a steady trend without grazing. These findings have implications for grassland ecosystem management as it relates to carbon sequestration and climate change mitigation, e.g., removal of grazing should be considered in strategies that aim to increase terrestrial carbon sequestrations at local and regional scales. One of the greatest limitations in quantifying the effects of herbivores on carbon cycling is identifying the grazing systems and intensities within a given region. We hope our study emphasizes the need for large-scale assessments of how grazing impacts carbon cycling. Most terrestrial ecosystems in Xinjiang have been affected by disturbances to a greater or lesser extent in the past

  2. Alcohol-related mortality, drinking behavior, and business cycles: are slumps really dry seasons?

    PubMed

    Johansson, Edvard; Böckerman, Petri; Prättälä, Ritva; Uutela, Antti

    2006-09-01

    This paper explores the connection between alcohol-related mortality, drinking behavior, and macroeconomic conditions in Finland using both aggregate and microlevel data from recent decades. The aggregate data reveal that an improvement in economic conditions produces a decrease in alcohol-related mortality. Microlevel data show that alcohol consumption increases during economic expansion while the probability of being a drinker remains unchanged. This demonstrates that alcohol-related mortality and self-reported alcohol consumption may be delinked in the short-run business cycle context. One explanation for this paradox is that most harmful forms of drinking are not captured in survey-based data used to study the effect of macroeconomic conditions on alcohol consumption. Our evidence does not overwhelmingly support the conclusions reported for the United States that temporary economic downturns are good for health.

  3. The capacity of soil particles for spontaneous formation of macroaggregates after a wetting-drying cycle

    NASA Astrophysics Data System (ADS)

    Kholodov, V. A.

    2013-06-01

    The capacity of soil particles for spontaneous formation of aggregates >0.25 mm was studied in a laboratory experiment. The particles from soil aggregates (3-1 mm) (initially aggregated particles, APs) and initially free particles (FPs) of <0.25 mm in size were isolated from the soddy-podzolic and chernozemic soils under fallow and from the arable soddy-podzolic soil. The aggregates of 3-1 mm were ground and passed through a 0.25-mm sieve. Then, the aggregates and free particles were poured with water and dried, and the content of the formed aggregates and their water stability were determined; in the samples from the arable soddy-podzolic soil, the organic carbon content was also determined in the newly formed aggregates. The FPs from the untilled soils formed almost no aggregates. At the same time, the APs from these soils manifested the ability for the spontaneous formation of aggregates, including water-stable aggregates. In the arable soddy-podzolic soil, on the contrary, both FPs and APs demonstrated the capacity for spontaneous self-organization into aggregates. The water stability of the self-organized aggregates from the arable soil was similar regardless of their source (APs or FPs). It was supposed that the ability of the FPs from the arable soil to form macroaggregates reflects the mechanical degradation of the aggregates in the soil: tillage results in the degradation of the aggregates, and the particles capable of spontaneously aggregation temporarily fall in the fraction of <0.25 mm. The water-stable aggregates produced from the APs or FPs of the arable soil contained more organic carbon (1.89%) in comparison with the water-stable aggregates separated from the initial 3- to 1-mm aggregates of this soil (1.31%).

  4. Effects of soil warming and drying on methane cycling in a northern peatland mesocosm study

    NASA Astrophysics Data System (ADS)

    White, Jeffrey R.; Shannon, Robert D.; Weltzin, Jake F.; Pastor, John; Bridgham, Scott D.

    2008-09-01

    Boreal peatlands contain a large portion of the Earth's terrestrial organic carbon and may be particularly vulnerable to changes in climate. Temperatures in boreal regions are predicted to increase during the twenty-first century which may accelerate changes in soil microbial processes and plant community dynamics. In particular, climate-driven changes in plant community composition might affect the pathways and rates of methanogenesis, the plant-mediated emission of methane, and the scavenging of methane by methanotrophic bacteria. Climate change may also affect methane cycling through changes in pore water chemistry. To date, these feedbacks have not been incorporated into the carbon cycling components of climate models. We investigated the effects of soil warming and water table manipulations on methane cycling in a field mesocosm experiment in northern Minnesota, USA. Large intact soil monoliths removed from a bog and fen received infrared warming treatments crossed with water table treatments for 6 years. In years 5 and 6, concentrations, fluxes, and isotopic compositions of methane were measured along with aboveground and belowground net primary productivity and pore water concentrations of acetate, sulfate, ammonium, nitrate, and dissolved organic carbon. Water table level was the dominant control over methane flux in the fen mesocosms, likely through its effect on methane oxidation rates. However, pore water chemistry and plant productivity were important secondary factors in explaining methane flux in the fen mesocosms, and these factors appeared to be the predominant controls over methane flux in the bog mesocosms. The water table and IR treatments had large effects on pore water chemistry and plant productivity, so the indirect effects of climate change appear to be just as important as the direct effects of changing temperature and water table level in controlling future methane fluxes from northern peatlands. Pore water sulfate, ammonium, nitrate, and

  5. Effect of Sini San freeze-dried powder on sleep-waking cycle in insomnia rats.

    PubMed

    Yan, Xingke; Zhang, Zeguo; Xu, Fuju; Li, Yuefeng; Zhu, Tiantian; Ma, Chongbing; Liu, Anguo

    2014-10-01

    To investigate the effects of the Sini San at different doses on each sleeping state [slow-wave sleep 1 (SWS 1), slow-wave sleep 2 (SWS2), rapid-eye-movement (REM), wakefulness (W)] in insomnia rats and to identify its mode of action for improving sleep. The insomnia rats were randomly divided into a high-, medium- or low-dose group of Sini San (equal to crude drug 8.8, 4.4, or 2.2 g/kg, respectively) for seven consecutive days. Compared with pre-administration, SWS2 was significantly increased after administration of the low dose. Compared with pre-administration, W was significantly decreased and SWS1, SWS2, and the total sleeping time (TST) were markedly increased after administration of the medium dose. Compared with pre-administration, W was significantly decreased and SWS1, SWS2, rapid-eye-movement sleep, and TST were significantly longer after administration of the high dose. The effects of Sini San on sleep-wake cycle are dose-dependent. The results suggest that Sini San extends SWS1 and SWS2, which increases the total sleeping time.

  6. The impacts of drying and rewetting cycles on potential methanogenesis in wetland soils

    NASA Astrophysics Data System (ADS)

    Kannenberg, S.; Ludwig, S.; Nelson, L.; Rich, H.; Spawn, S.; Porterfield, J.; Schade, J. D.

    2012-12-01

    Wetlands are currently the world's largest natural emitter of methane, a greenhouse gas that is over 20 times more effective at trapping heat than carbon dioxide. The magnitude of expansion and contraction of wetlands is likely to increase in response to greater severity of precipitation and drought events predicted by climate change models. Increased severity of precipitation and drought events will result in greater variability in size and ephemerality of wetlands. One possible outcome of these size fluctuations is the increase in the anoxic areas preferred by methanogens. Thus, it is becoming increasingly important to discover how production of methane may change as conditions vary. Our objective was to investigate how wetland dynamics, including variability in size and ephemerality, affect methanogenesis and influence the underlying microbial community. We sampled soil from three wetlands of differing ephemerality on the St. Olaf Natural Lands. We measured water and KCl-extractable NO3 and NH4 and used chloroform-fumigation direct-extraction (CFDE) to estimate microbial biomass in each soil sample. Subsamples of each core were incubated in bottles under anoxic conditions in the dark to measure rate of methane production. Bottles were incubated for 9 weeks and headspace samples were collected after 2, 24, and 48 hours and 1 week, and then weekly thereafter. Headspace samples were analyzed for CH4 to calculate rates of methanogenesis. The rate of methane production over the first 48 hours was positively correlated with soil moisture, and negatively correlated with nitrate levels. At the end of the incubation period, methane production was not related to moisture and nitrate, and was positively correlated with soil organic matter. In addition, we observed a lag time before the onset of significant methane flux, followed by a rapid increase in concentration. This lag time was shorter in wet soils than in dry soils. These data suggest that wet, low-nitrate soils

  7. The repeated drying-wetting and freezing-thawing cycles affect only the active pool of soil organic matter

    NASA Astrophysics Data System (ADS)

    Semenov, Vyacheslav; Zinyakova, Natalya; Tulina, Anastasiya

    2016-04-01

    The decrease in the content of soil organic carbon, particularly in active form, is one of the major problems of the 21st century, which is closely related to the disturbance of the biogeochemical carbon cycle and to the increase in the emission of carbon dioxide into the atmosphere. The main reasons for the SOM losses are the surplus of the SOM active pool losses due to mineralization, erosion, and infiltration over the input of fresh organic matter to the soil, as well as the changes in the soil conditions and processes due to natural and anthropogenic disturbing impacts. Experiments were carried out with mixed samples from the upper layers of soddy-podzolic soil, gray forest soil, and typical chernozems. Soil samples as controls were incubated after wetting for 150 days. The dynamics and cumulative production of C-CO2 under stable temperature (22°C) and moisture conditions were determined; the initial content of potentially mineralizable organic matter (C0) in the soil at the beginning of the incubation was then calculated to use these data as the control. Other soil samples were exposed in flasks to the following successive treatments: wetting →incubation → freezing → thawing → incubation →drying. Six repeated cycles of disturbing impacts were performed for 140 days of the experiment. After six cycles, the soil samples were incubated under stable temperature and moisture conditions for 150 days. The wetting of dried soils and the thawing of frozen soils are accompanied by the pulsed dynamics of the C-CO2 production with an abrupt increase in the rate of the C-CO2 emission within several days by 2.7-12.4 and 1.6-2.7 times, respectively, compared to the stable incubation conditions. The rate of the C-CO2 production pulses under each subsequent impact decreased compared to the preceding one similarly for all studied soils, which could be due to the depletion in potentially mineralizable soil organic matter (C0). The cumulative extra C-CO2 production by

  8. Impact of Aeolian Dry Deposition of Reactive Iron Minerals on Sulfur Cycling in Sediments of the Gulf of Aqaba

    PubMed Central

    Blonder, Barak; Boyko, Valeria; Turchyn, Alexandra V.; Antler, Gilad; Sinichkin, Uriel; Knossow, Nadav; Klein, Rotem; Kamyshny, Alexey

    2017-01-01

    The Gulf of Aqaba is an oligotrophic marine system with oxygen-rich water column and organic carbon-poor sediments (≤0.6% at sites that are not influenced by anthropogenic impact). Aeolian dust deposition from the Arabian, Sinai, and Sahara Deserts is an important source of sediment, especially at the deep-water sites of the Gulf, which are less affected by sediment transport from the Arava Desert during seasonal flash floods. Microbial sulfate reduction in sediments is inferred from the presence of pyrite (although at relatively low concentrations), the presence of sulfide oxidation intermediates, and by the sulfur isotopic composition of sulfate and solid-phase sulfides. Saharan dust is characterized by high amounts of iron minerals such as hematite and goethite. We demonstrated, that the resulting high sedimentary content of reactive iron(III) (hydr)oxides, originating from this aeolian dry deposition of desert dust, leads to fast re-oxidation of hydrogen sulfide produced during microbial sulfate reduction and limits preservation of reduced sulfur in the form of pyrite. We conclude that at these sites the sedimentary sulfur cycle may be defined as cryptic. PMID:28676799

  9. Effects of Wet/Dry-Cycling and Plasma Treatments on the Properties of Flax Nonwovens Intended for Composite Reinforcing

    PubMed Central

    Ventura, Heura; Claramunt, Josep; Navarro, Antonio; Rodriguez-Perez, Miguel A.; Ardanuy, Mònica

    2016-01-01

    This research analyzes the effects of different treatments on flax nonwoven (NW) fabrics which are intended for composite reinforcement. The treatments applied were of two different kinds: a wet/dry cycling which helps to stabilize the cellulosic fibers against humidity changes and plasma treatments with air, argon and ethylene gases considering different conditions and combinations, which produce variation on the chemical surface composition of the NWs. The resulting changes in the chemical surface composition, wetting properties, thermal stability and mechanical properties were determined. Variations in surface morphology could be observed by scanning electron microscopy (SEM). The results of the X-ray photoelectron spectroscopy (XPS) showed significant changes to the surface chemistry for the samples treated with argon or air (with more content on polar groups on the surface) and ethylene plasma (with less content of polar groups). Although only slight differences were found in moisture regain and water retention values (WRV), significant changes were found on the contact angle values, thus revealing hydrophilicity for the air-treated and argon-treated samples and hydrophobicity for the ethylene-treated ones. Moreover, for some of the treatments the mechanical testing revealed an increase of the NW breaking force. PMID:28787893

  10. Impact of Aeolian Dry Deposition of Reactive Iron Minerals on Sulfur Cycling in Sediments of the Gulf of Aqaba.

    PubMed

    Blonder, Barak; Boyko, Valeria; Turchyn, Alexandra V; Antler, Gilad; Sinichkin, Uriel; Knossow, Nadav; Klein, Rotem; Kamyshny, Alexey

    2017-01-01

    The Gulf of Aqaba is an oligotrophic marine system with oxygen-rich water column and organic carbon-poor sediments (≤0.6% at sites that are not influenced by anthropogenic impact). Aeolian dust deposition from the Arabian, Sinai, and Sahara Deserts is an important source of sediment, especially at the deep-water sites of the Gulf, which are less affected by sediment transport from the Arava Desert during seasonal flash floods. Microbial sulfate reduction in sediments is inferred from the presence of pyrite (although at relatively low concentrations), the presence of sulfide oxidation intermediates, and by the sulfur isotopic composition of sulfate and solid-phase sulfides. Saharan dust is characterized by high amounts of iron minerals such as hematite and goethite. We demonstrated, that the resulting high sedimentary content of reactive iron(III) (hydr)oxides, originating from this aeolian dry deposition of desert dust, leads to fast re-oxidation of hydrogen sulfide produced during microbial sulfate reduction and limits preservation of reduced sulfur in the form of pyrite. We conclude that at these sites the sedimentary sulfur cycle may be defined as cryptic.

  11. Effects of Wet/Dry-Cycling and Plasma Treatments on the Properties of Flax Nonwovens Intended for Composite Reinforcing.

    PubMed

    Ventura, Heura; Claramunt, Josep; Navarro, Antonio; Rodriguez-Perez, Miguel A; Ardanuy, Mònica

    2016-02-03

    This research analyzes the effects of different treatments on flax nonwoven (NW) fabrics which are intended for composite reinforcement. The treatments applied were of two different kinds: a wet/dry cycling which helps to stabilize the cellulosic fibers against humidity changes and plasma treatments with air, argon and ethylene gases considering different conditions and combinations, which produce variation on the chemical surface composition of the NWs. The resulting changes in the chemical surface composition, wetting properties, thermal stability and mechanical properties were determined. Variations in surface morphology could be observed by scanning electron microscopy (SEM). The results of the X-ray photoelectron spectroscopy (XPS) showed significant changes to the surface chemistry for the samples treated with argon or air (with more content on polar groups on the surface) and ethylene plasma (with less content of polar groups). Although only slight differences were found in moisture regain and water retention values (WRV), significant changes were found on the contact angle values, thus revealing hydrophilicity for the air-treated and argon-treated samples and hydrophobicity for the ethylene-treated ones. Moreover, for some of the treatments the mechanical testing revealed an increase of the NW breaking force.

  12. Effects of Wet-Dry Cycling on the Mobility of Cs, Sr, Cr, Cd, and U in Idaho National Environmental and Engineering Laboratory (INEEL) Soil and Soil Constituents

    NASA Astrophysics Data System (ADS)

    Wright, K. E.; Cooper, D. C.; Bauer, W. F.; Redden, G. D.

    2002-12-01

    The INEEL, located on the Snake River Plain in eastern Idaho, is the site of surface and subsurface radionuclide contamination stemming from decades of nuclear waste handling, storage, and disposal. Infiltration in this arid region occurs primarily in the spring with snow melt and stream flooding. We hypothesize that long periods of dry weather, punctuated by short, intense periods of recharge, create environmental conditions that accelerate the geochemical processes that sequester contaminants within less mobile phases. This hypothesis predicts slow contaminant migration that is strongly impacted by stochastic heavy-infiltration events that enable particle-facilitated transport. Preliminary results from sequential wet-dry experiments conducted with no-sediment, INEEL sediment, quartz, goethite-coated quartz, and andesine exposed to 200μM Cs, Sr, Cd, Cr and U indicate that wet-dry cycling does impact contaminant sorption under simulated environmental conditions. All sediments were also exposed to these metals under a "continuously-wet" control condition. No evidence for Cs+ sorption was seen during the initial equilibration period for quartz, Fe-quartz (goethite-coated quartz), and the no-sediment control. During this period, the percentage of Cs+ remaining in the aqueous phase decreased to 42.5% and 1.45% for andesine and soil, respectively. Wet-dry cycling reduced the [Cs+-aq] in the INEEL sediment to 0.8%, but did not notably affect the [Cs+-aq] in the other treatments. The behavior of Sr2+ was similar to Cs+, except in the INEEL sediment, where the [Sr2+-aq] increased from 14.5% to 19.5% during the wet-dry cycling period. At initial equilibration, [U6+-aq] had decreased notably in all samples, but especially in soil, Fe-quartz, and quartz treatments, which decreased by a factor of 10. In all treatments, the [U6+-aq] decreased by an additional factor of 10 during the wet-dry cycling period. Cs+ behavior is consistent with ion exchange mechanisms prevalent in

  13. Influence of 13 different biochars on N2O production and its sources during rewetting-drying cycles

    NASA Astrophysics Data System (ADS)

    Wrage-Mönnig, Nicole; Fiedler, Sebastian; Fuertes-Mendizábal, Teresa; Estavillo, José-Maria; Ippolito, Jim A.; Borchard, Nils; Cayuela, Maria Luz; Spokas, Kurt; Novak, Jeff; Kammann, Claudia

    2017-04-01

    Biochars have been found to have variable impacts on nitrous oxide (N2O) emissions. The variability has been attributed to differences in soil - biochar properties and microbial communities. While some information exists on biochar and soil properties, the effect of biochars on microbial sources of N2O is still a matter of speculation. In this study, we tested these effects for12 biochars prepared from cypress, loblolly pine and grape wood produced at four different controlled temperatures (350, 500, 700 and 900˚ C), respectively, plus a grapevine Kontiki biochar (600-700˚ C). The biochars were added (2%) to a loamy sand brought to pH 7.1 with CaO. The treatments plus one control were pre-incubated at 40% water holding capacity (WHC) for four days. Then, they were brought to 80% WHC and 15N-nitrate was added (50 mg NO3-N kg-1 soil, 10% enriched in 15N). All treatments were set up with four replicates. In total, three cycles of (re)wetting - drying (80 to 40% WHC, total duration 20 days) were monitored. Samples for analyses of N2O concentrations and stable isotope signatures were taken daily (except for weekends) after closing the incubation vessels for 90 minutes. N2O emissions increased with each addition of water and decreased during drying to background values. Each rewetting led to larger emissions than measured in the previous cycle for all treatments including controls. All biochars decreased total N2O emissions compared to the control treatments. The higher the production temperature of the biochar, the larger usually the emission reduction. Largest effects were found for the grape wood and the Kontiki biochars. Interestingly, the addition of biochars also changed the isotopic signatures of the emitted N2O. Whereas emissions in the controls were enriched to about 5 atom% 15N excess at peak emissions, the enrichment was usually less after addition of biochars (1-5 atom% excess). Again, this effect tended to be larger at higher production temperatures of the

  14. Modeling the dry-weather tidal cycling of fecal indicator bacteria in surface waters of an intertidal wetland.

    PubMed

    Sanders, Brett F; Arega, Feleke; Sutula, Martha

    2005-09-01

    Recreational water quality at beaches in California and elsewhere is often poor near the outlets of rivers, estuaries, and lagoons. This condition has prompted interest in the role of wetlands in modulating surface water concentrations of fecal indicator bacteria (FIB), the basis of water quality standards internationally. A model was developed and applied to predict the dry-weather tidal cycling of FIB in Talbert Marsh, an estuarine, intertidal wetland in Huntington Beach, California, in response to loads from urban runoff, bird feces, and resuspended sediments. The model predicts the advection, dispersion and die-off of total coliform, Escherichia coli, and enterococci using a depth-integrated formulation. We find that urban runoff and resuspension of contaminated wetland sediments are responsible for surface water concentrations of FIB in the wetland. Model predictions show that urban runoff controls surface water concentrations at inland sites and sediment resuspension controls surface water concentrations near the mouth. Direct wash-off of bird feces into the surface water is not a significant contributor, although bird feces can contribute to the sediment bacteria load. The key parameters needed to accurately predict FIB concentrations, using a validated hydrodynamic model, are: the load due to urban runoff, sediment erodibility parameters, and sediment concentrations and surface water die-off rates of enteric bacteria. In the present study, literature values for sediment erodibility and water column die-off rates are used and average concentrations of FIB are predicted within 1/2 log unit of measurements. Total coliform are predicted more accurately than E. coli or enterococci, both in terms of magnitude and tidal variability. Since wetland-dependent animals are natural sources of FIB, and FIB survive for long periods of time and may multiply in wetland sediments, these results highlight limitations of FIB as indicators of human fecal pollution in and near

  15. Product mass transfer resistance directly determined during freeze-drying cycle runs using tunable diode laser absorption spectroscopy (TDLAS) and pore diffusion model.

    PubMed

    Kuu, Wei Y; O'Bryan, Kevin R; Hardwick, Lisa M; Paul, Timothy W

    2011-08-01

    The pore diffusion model is used to express the dry layer mass transfer resistance, [Formula: see text], as a function of the ratio r(e)/?, where r(e) is the effective pore radius and ? is the tortuosity factor of the dry layer. Using this model, the effective pore radius of the dry layer can be estimated from the sublimation rate and product temperature profiles measured during primary drying. Freeze-drying cycle runs were performed using the LyoStar II dryer (FTS Systems), with real-time sublimation rate profiles during freeze drying continuously measured by tunable diode laser absorption spectroscopy (TDLAS). The formulations chosen for demonstration of the proposed approach include 5% mannitol, 5% sucrose, 5% lactose, 3% mannitol plus 2% sucrose, and a parenteral nutrition formulation denoted VitaM12. The three different methods used for determination of the product resistance are: (1) Using both the sublimation rate and product temperature profiles, (2) using the sublimation rate profile alone, and (3) using the product temperate profile alone. Unlike the second and third methods, the computation procedure of first method does not need solution of the complex heat and mass transfer equations.

  16. Sequestration of Metals by wet-dry Cycling of Soil and Soil Minerals at the Idaho Engineering and Environmental Laboratory (INEEL)

    NASA Astrophysics Data System (ADS)

    Wright, K. E.; Cooper, D. C.; Redden, G. D.; Bauer, W. F.

    2003-12-01

    The INEEL is the site of soil contamination by heavy metals and nuclides stemming from decades of nuclear waste processing, storage, and disposal. Much of the contamination is located within 1m of the surface, where contaminant movement can be influenced by the cyclic wetting and drying cycles that result from large amounts of infiltration in the spring followed by months of hot weather with little precipitation. We hypothesize that such wetting and drying cycles can retard contaminant migration by sequestering metals in less reactive phases. INEEL soil, quartz, goethite-coated quartz (Fe-quartz), andesine, Ca-montmorillonite, K-feldspar, calcite, smectite-illite, kaolinite and a no-matrix control were exposed to 200μ M Cs, Sr, Cd, Cr, and U. After a two-week equilibration period, metals were analyzed using ICP-AES and ICP-MS. Samples were then evaporated to dryness and were subsequently re-wetted with air-equilibrated deionized water. This process was repeated four times; results were compared to continuously wet control samples. Preliminary results indicate that wet-dry cycling generally reduces metal availability, but the magnitude of the effect depends on the metal and the substrate with which it interacts. Control samples with no solid substrate showed no decrease in metal content throughout the experiment except for [U6+-aq] and [Cd2+-aq], which were oversaturated at the experiment's inception. The largest differences between wet-dry cycled samples versus their continuously wet counterparts occurred with U, Cd, and Cr. [U6+-aq] was reduced by nearly 100% in cycled andesine samples compared to 25% in continuously wet control samples. [Cd2+-aq] in cycled soil, Fe-quartz, quartz, and no matrix samples was up to 50% lower in concentration than that present in control samples. Results for [Cr6+-aq] were similar, but with no difference in concentration for the no-matrix control. Differences in [Sr2+-aq] and [Cs+-aq] for cycled samples compared to control samples

  17. Responses of methanogen mcrA genes and their transcripts to an alternate dry/wet cycle of paddy field soil.

    PubMed

    Ma, Ke; Conrad, Ralf; Lu, Yahai

    2012-01-01

    Intermittent drainage can substantially reduce methane emission from rice fields, but the microbial mechanisms remain poorly understood. In the present study, we determined the rates of methane production and emission, the dynamics of ferric iron and sulfate, and the abundance of methanogen mcrA genes (encoding the alpha subunit of methyl coenzyme M reductase) and their transcripts in response to alternate dry/wet cycles in paddy field soil. We found that intermittent drainage did not affect the growth of rice plants but significantly reduced the rates of both methane production and emission. The dry/wet cycles also resulted in shifts of soil redox conditions, increasing the concentrations of ferric iron and sulfate in the soil. Quantitative PCR analysis revealed that both mcrA gene copies and mcrA transcripts significantly decreased after dry/wet alternation compared to continuous flooding. Correlation and regression analyses showed that the abundance of mcrA genes and transcripts positively correlated with methane production potential and soil water content and negatively correlated with the concentrations of ferric iron and sulfate in the soil. However, the transcription of mcrA genes was reduced to a greater extent than the abundance of mcrA genes, resulting in very low mcrA transcript/gene ratios after intermittent drainage. Furthermore, terminal restriction fragment length polymorphism analysis revealed that the composition of methanogenic community remained stable under dry/wet cycles, whereas that of metabolically active methanogens strongly changed. Collectively, our study demonstrated a stronger effect of intermittent drainage on the abundance of mcrA transcripts than of mcrA genes in rice field soil.

  18. Responses of Methanogen mcrA Genes and Their Transcripts to an Alternate Dry/Wet Cycle of Paddy Field Soil

    PubMed Central

    Ma, Ke; Conrad, Ralf

    2012-01-01

    Intermittent drainage can substantially reduce methane emission from rice fields, but the microbial mechanisms remain poorly understood. In the present study, we determined the rates of methane production and emission, the dynamics of ferric iron and sulfate, and the abundance of methanogen mcrA genes (encoding the alpha subunit of methyl coenzyme M reductase) and their transcripts in response to alternate dry/wet cycles in paddy field soil. We found that intermittent drainage did not affect the growth of rice plants but significantly reduced the rates of both methane production and emission. The dry/wet cycles also resulted in shifts of soil redox conditions, increasing the concentrations of ferric iron and sulfate in the soil. Quantitative PCR analysis revealed that both mcrA gene copies and mcrA transcripts significantly decreased after dry/wet alternation compared to continuous flooding. Correlation and regression analyses showed that the abundance of mcrA genes and transcripts positively correlated with methane production potential and soil water content and negatively correlated with the concentrations of ferric iron and sulfate in the soil. However, the transcription of mcrA genes was reduced to a greater extent than the abundance of mcrA genes, resulting in very low mcrA transcript/gene ratios after intermittent drainage. Furthermore, terminal restriction fragment length polymorphism analysis revealed that the composition of methanogenic community remained stable under dry/wet cycles, whereas that of metabolically active methanogens strongly changed. Collectively, our study demonstrated a stronger effect of intermittent drainage on the abundance of mcrA transcripts than of mcrA genes in rice field soil. PMID:22101043

  19. Plague cycles in two rodent species from China: Dry years might provide context for epizootics in wet years

    USGS Publications Warehouse

    Eads, David; Biggins, Dean E.; Xu, Lei; Liu, Qiyong

    2016-01-01

    Plague, a rodent-associated, flea-borne zoonosis, is one of the most notorious diseases in history. Rates of plague transmission can increase when fleas are abundant. Fleas commonly desiccate and die when reared under dry conditions in laboratories, suggesting fleas will be suppressed during droughts in the wild, thus reducing the rate at which plague spreads among hosts. In contrast, fleas might increase in abundance when precipitation is plentiful, producing epizootic outbreaks during wet years. We tested these hypotheses using a 27-yr data set from two rodents in Inner Mongolia, China: Mongolian gerbils (Meriones unguiculatus) and Daurian ground squirrels (Spermophilus dauricus). For both species of rodents, fleas were most abundant during years preceded by dry growing seasons. For gerbils, the prevalence of plague increased during wet years preceded by dry growing seasons. If precipitation is scarce during the primary growing season, succulent plants decline in abundance and, consequently, herbivorous rodents can suffer declines in body condition. Fleas produce more offspring and better survive when parasitizing food-limited hosts, because starving animals tend to exhibit inefficient behavioral and immunological defenses against fleas. Further, rodent burrows might buffer fleas from xeric conditions aboveground during dry years. After a dry year, fleas might be abundant due to the preceding drought, and if precipitation and succulent plants become more plentiful, rodents could increase in density, thereby creating connectivity that facilitates the spread of plague. Moreover, in wet years, mild temperatures might increase the efficiency at which fleas transmit the plague bacterium, while also helping fleas to survive as they quest among hosts. In this way, dry years could provide context for epizootics of plague in wet years.

  20. Scale-dependent variation in nitrogen cycling and soil fungal communities along gradients of forest composition and age in regenerating tropical dry forests.

    PubMed

    Waring, Bonnie G; Adams, Rachel; Branco, Sara; Powers, Jennifer S

    2016-01-01

    Rates of ecosystem nitrogen (N) cycling may be mediated by the presence of ectomycorrhizal fungi, which compete directly with free-living microbes for N. In the regenerating tropical dry forests of Central America, the distribution of ectomycorrhizal trees is affected by succession and soil parent material, both of which may exert independent influence over soil N fluxes. In order to quantify these interacting controls, we used a scale-explicit sampling strategy to examine soil N cycling at scales ranging from the microsite to ecosystem level. We measured fungal community composition, total and inorganic N pools, gross proteolytic rate, net N mineralization and microbial extracellular enzyme activity at multiple locations within 18 permanent plots that span dramatic gradients of soil N concentration, stand age and forest composition. The ratio of inorganic to organic N cycling was correlated with variation in fungal community structure, consistent with a strong influence of ectomycorrhiza on ecosystem-scale N cycling. However, on average, > 61% of the variation in soil biogeochemistry occurred within plots, and the effects of forest composition were mediated by this local-scale heterogeneity in total soil N concentrations. These cross-scale interactions demonstrate the importance of a spatially explicit approach towards an understanding of controls on element cycling. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  1. Photoprotection related to xanthophyll cycle pigments in epiphytic orchids acclimated at different light microenvironments in two tropical dry forests of the Yucatan Peninsula, Mexico.

    PubMed

    de la Rosa-Manzano, Edilia; Andrade, José Luis; García-Mendoza, Ernesto; Zotz, Gerhard; Reyes-García, Casandra

    2015-12-01

    Epiphytic orchids from dry forests of Yucatán show considerable photoprotective plasticity during the dry season, which depends on leaf morphology and host tree deciduousness. Nocturnal retention of antheraxanthin and zeaxanthin was detected for the first time in epiphytic orchids. In tropical dry forests, epiphytes experience dramatic changes in light intensity: photosynthetic photon flux density may be up to an order of magnitude higher in the dry season compared to the wet season. To address the seasonal changes of xanthophyll cycle (XC) pigments and photosynthesis that occur throughout the year, leaves of five epiphytic orchid species were studied during the early dry, dry and wet seasons in a deciduous and a semi-deciduous tropical forests at two vertical strata on the host trees (3.5 and 1.5 m height). Differences in XC pigment concentrations and photosynthesis (maximum quantum efficiency of photosystem II; F v/F m) were larger among seasons than between vertical strata in both forests. Antheraxanthin and zeaxanthin retention reflected the stressful conditions of the epiphytic microhabitat, and it is described here in epiphytes for the first time. During the dry season, both XC pigment concentrations and photosystem II heat dissipation of absorbed energy increased in orchids in the deciduous forest, while F v/F m and nocturnal acidification (ΔH(+)) decreased, clearly as a response to excessive light and drought. Concentrations of XC pigments were higher than those in orchids with similar leaf shape in semi-deciduous forest. There, only Encyclia nematocaulon and Lophiaris oerstedii showed somewhat reduced F v/F m. No changes in ΔH(+) and F v/F m were detected in Cohniella ascendens throughout the year. This species, which commonly grows in forests with less open canopies, showed leaf tilting that diminished light interception. Light conditions in the uppermost parts of the canopy probably limit the distribution of epiphytic orchids and the retention of

  2. Soil physical properties changed induced by dry-wet cycles in the water-level fluctuation zone of Three Gorges Reservoir region, China

    NASA Astrophysics Data System (ADS)

    Cui, Junfang; Tang, Xiangyu; Zhang, Wei

    2017-04-01

    In southwest China, a grand hydraulic engineering called Three Gorges Dam (TGD) was completed and under full power run since 2009, making a total area of 349 km2 along Yangtze River exposing the dry-wet cycles by its impounding of water step by step from the elevations of 135 m in summer season to 175 m in winter season at each year. As populated area, the environmental issues aroused by the TGR have centered on water quality, biodiversity, sedimentation, downstream riverbed erosion and pollutants (both heavy metals and organic pollutants) transportation. All these are regulated or affected by soil structure and pore network, directly or indirectly. Thus, the study of soil physical quality changed induced by these seasonal dry-wet cycles is crucial. The objective of this study is: (1) to describe soil structural status in WLF zone of TGR by combination of laboratory measures and visual evaluation method; (2) to describe the pore system in this zone by both SWRC and CT images; and (3) to address the changes of soil physical quality changed by seasonal dry-wet cycles. Our results showed a deterioration of soil structure (indicated by a high Sq score in VESS) and soil aggregate stability (indicated by low MWD and the mass fractal dimension Dm) in lower land of TGR. The data from both soil water retention curve and micro-CT image demonstrates a going -worse of soil physical quality by decreasing of soil pore number and porosity as well as a shift of drainable micro-pores (0.1 < r < 125 µm) to non-drainable micro-pores (r < 0.1 µm) in the lower land of TGR.

  3. Quantitative determination of the effect of temperature on mudstone decay during wet-dry cycles: A case study of 'purple mudstone' from south-western China

    NASA Astrophysics Data System (ADS)

    Zhang, Dan; Chen, Anqiang; Wang, Xuemei; Liu, Gangcai

    2015-10-01

    Although temperature is considered a key factor influencing rock decay, little is known about the quantitative relationship between a rock's decay rate and temperature, which makes it difficult to quantitatively predict the rate of rock decay under varied temperature during wetting-drying cycle conditions. Thus, the aim of the present paper was to observe the decay rate of various purple mudstones and to develop a model with which to calculate their decay rates under varied temperature conditions. Three types of purple mudstone were sampled from the Tuodian group (J3t), Matoushan group (K2m) and Lufeng group (J1l), located in the Chuxiong district of Yunnan province, south-western China. All samples were manually cut into cubes of 50 × 50 × 50 mm, before being subjected to 39 wetting-drying cycles in a 2 mm sieve under artificial constant temperature, natural daily temperature variation and artificial temperature alternation (minimum and maximum) treatments in the laboratory. Decay rates were calculated by weighing the mass remaining in the sieve after each treatment cycle. The results showed that the decay rates of the tested rocks rose with an increase in temperature and temperature difference (maximum-minimum), with the rank order of decay rate being J3t > K2m > J1l. Quantitative analysis revealed rock decay rate to be significantly related to temperature by a power function, and exponentially related to temperature difference. Our results suggested that temperature difference has a stronger effect on purple mudstone decay than that of temperature magnitude during the wetting-drying processes.

  4. Mössbauer and XRD analysis of corrosion products on weathering steel treated by wet-dry cycles using various solutions

    NASA Astrophysics Data System (ADS)

    Oyabu, Matashige; Nomura, Kiyoshi; Koike, Yuya; Okazawa, Atsushi

    2016-12-01

    Weathering steels (COR-TEN) were corroded by wet-dry cycles using a splay of various solutions in a laboratory. Corrosion products on weathering steel were characterized by X-ray diffractometry and Mössbauer spectrometry at room and low temperatures. Fine α-FeOOH, γ-FeOOH and γ-Fe 2 O 3 are fundamentally formed in various atmospheric conditions. β-FeOOH is additionally formed under the existence of chloride ions, but not formed when sulfate ions are coexisting. Spraying a NaF solution prevents the progress of corrosion.

  5. Coupled effects of treated effluent irrigation and wetting-drying cycles on transport of triazines through unsaturated soil columns.

    PubMed

    Seol, Y; Lee, L S

    2001-01-01

    The physical and chemical parameters controlling the movement of atrazine (6-chloro-N2-ethyl-N4-isopropyl-l,3,5-triazine-2,4-diamine; 98.8%) and prometryn [N,N'-bis(1-methylethyl)-6-(methylthio)-l,3,5triazine-2,4-diamine; 99.5%] were investigated in columns infiltrated with treated effluent under unsaturated transient conditions and subjected to drying events at 22 or 60 degrees C followed by rewetting. Three soils varying in soil pH and texture and three solutions were used. The infiltrating solutions consisted of either a CaCl2 matrix (CC), a swine waste-derived lagoon effluent (SW), or a simulated buffer solution (SB) representative of the element composition and pH of the SW but with no dissolved organic matter. Several parameters were monitored including leachate triazine concentrations, pH, dissolved organic carbon (DOC), inorganic carbon, and flow rates. Compared with CC, application of SW and SB increased column leachate pH, enhanced dissolution of organic carbon and particle dispersion, and decreased average flow rates, which allowed for increased desorption time. The coupled effect of these processes enhanced movement of triazines in some cases, with SW generally having the greatest effect. The individual effect of increased pH was more pronounced for prometryn (pKa=4.05) versus atrazine (pKa=1.66), and most dramatic for the soil with the lowest initial pH. High-temperature drying, which simulated intensive evaporation, further enhanced the dissolution of soil organic matter and the reduction in leachate flow rates with SW and SB applications; however, the net effect under the experimental conditions employed varied with soil type. Relative to low-temperature drying, high-temperature drying in the silty clay loam-packed columns reduced pesticide migration.

  6. Priming effect of 13C-labelled wheat straw in no-tillage soil under drying and wetting cycles in the Loess Plateau of China

    PubMed Central

    Liu, Enke; Wang, Jianbo; Zhang, Yanqing; Angers, Denis A.; Yan, Changrong; Oweis, Theib; He, Wenqing; Liu, Qin; Chen, Baoqing

    2015-01-01

    The objectives of this study were to determine the effects of drying and wetting (DW) cycles on soil organic carbon (SOC) mineralisation and on the priming effect (PE) induced by the addition of 13C-labelled wheat straw to long-term no-tillage (NT) and conventional-tillage (CT) soils. We observed that the SOC mineralisation rate in rewetted soils was greater than that in soils that were kept at constant water content. The proportion of CO2 derived from the straw declined dramatically during the first 10 days. The priming direction was first positive, and then became slightly negative. The PE was higher under DW cycles than under constant water content. There was no significant effect of the tillage system on the SOC mineralisation rate or PE. The data indicate that the DW cycles had a significant effect on the SOC mineralisation rate and on the PE, demonstrating a positive combined effect between wheat straw and moisture fluctuations. Further research is needed to study the role of microbial communities and C pools in affecting the SOC mineralisation response to DW cycles. PMID:26345303

  7. Hydration and dehydration cycles in polymer electrolyte fuel cells operated with wet anode and dry cathode feed: A neutron imaging and modeling study

    NASA Astrophysics Data System (ADS)

    García-Salaberri, P. A.; Sánchez, D. G.; Boillat, P.; Vera, M.; Friedrich, K. A.

    2017-08-01

    Proper water management plays an essential role in the performance and durability of Polymer Electrolyte Fuel Cells (PEFCs), but it is challenged by the variety of water transport phenomena that take place in these devices. Previous experimental work has shown the existence of fluctuations between low and high current density levels in PEFCs operated with wet hydrogen and dry air feed. The alternation between both performance states is accompanied by strong changes in the high frequency resistance, suggesting a cyclic hydration and dehydration of the membrane. This peculiar scenario is examined here considering liquid water distributions from neutron imaging and predictions from a 3D two-phase non-isothermal model. The results show that the hydration-dehydration cycles are triggered by the periodic condensation and shedding of liquid water at the anode inlet. The input of liquid water humidifies the anode channel and offsets the membrane dry-out induced by the dry air stream, thus leading to the high-performance state. When liquid water is flushed out of the anode channel, the dehydration process takes over, and the cell comes back to the low-performance state. The predicted amplitude of the current oscillations grows with decreasing hydrogen and increasing air flow rates, in agreement with previous experimental data.

  8. Ground surface temperature and humidity, ground temperature cycles and the ice table depths in University Valley, McMurdo Dry Valleys of Antarctica

    NASA Astrophysics Data System (ADS)

    Fisher, David A.; Lacelle, Denis; Pollard, Wayne; Davila, Alfonso; McKay, Christopher P.

    2016-11-01

    In the upper McMurdo Dry Valleys, 90% of the measured ice table depths range from 0 to 80 cm; however, numerical models predict that the ice table is not in equilibrium with current climate conditions and should be deeper than measured. This study explored the effects of boundary conditions (air versus ground surface temperature and humidity), ground temperature cycles, and their diminishing amplitude with depth and advective flows (Darcy flow and wind pumping) on water vapor fluxes in soils and ice table depths using the REGO vapor diffusion model. We conducted a series of numerical experiments that illustrated different hypothetical scenarios and estimated the water vapor flux and ice table depth using the conditions in University Valley, a small high elevation valley. In situ measurements showed that while the mean annual ground surface temperature approximates that in the air, the mean annual ground surface relative humidity (>85%ice) was significantly higher than in the atmosphere ( 50%ice). When ground surface temperature and humidity were used as boundary conditions, along with damping diurnal and annual temperature cycles within the sandy soil, REGO predicted that measured ice table depths in the valley were in equilibrium with contemporary conditions. Based on model results, a dry soil column can become saturated with ice within centuries. Overall, the results from the new soil data and modeling have implications regarding the factors and boundary conditions that affect the stability of ground ice in cold and hyperarid regions where liquid water is rare.

  9. Dynamic effects of wet-dry cycles and crust formation on the saturated hydraulic conductivity of surface soils in the constructed Hühnerwasser ("Chicken Creek") catchment

    NASA Astrophysics Data System (ADS)

    Hinz, Christoph; Schümberg, Sabine; Kubitz, Anita; Frank, Franzi; Cheng, Zhang; Nanu Frechen, Tobias; Pohle, Ina

    2016-04-01

    Highly disturbed soils and substrates used in land rehabilitation undergo rapid changes after the first wetting events which in turn can lead to ecosystem degradation. Such changes were detected during the early development of the constructed Hühnerwasser ("Chicken Creek") catchment in Lusatia, Germany. Surface substrates consisting of quaternary sandy sediments formed surface seals during the first rainfall events leading to reduced infiltration and substantially increased surface runoff. Subsequently biological soil crusts formed and stabilised the surface. The aim of this study is to investigate the factors that cause the hydraulic conductivity to decrease using undisturbed and disturbed soil samples. Based on the hypothesis that physical and biological crusts lower the hydraulic conductivity, the first set of experiments with undisturbed soil cores from the Hühnerwasser catchment were carried out to measure the saturated hydraulic conductivity using the constant head method. Measurements were done with intact cores and repeated after the surface crust was removed. As the quaternary glacial sediments tend to display hard setting behaviour, we further hypothesised that the mobilisation of fine particles within the cores lead to pore clogging and that wet-dry cycles will therefore decrease hydraulic conductivity. A second set of experiments using the same methodology consisted of five repeated measurements of hydraulic conductivity after each drying cycle. These measurements were done with undisturbed core samples as well as repacked cores in order to assess how dry packing affects the dynamics of the hydraulic conductivity somewhat similar to the situation during the first wetting after completion of the catchment construction. For all experiments, the temporal evolution of hydraulic conductivity was measured and the turbidity of the effluent was recorded. The results clearly demonstrated that the substrate is highly unstable. The first set of experiments

  10. Dry Mouth

    MedlinePlus

    ... of this page please turn Javascript on. Dry Mouth What Is Dry Mouth? Dry mouth is the feeling that there is ... when a person has dry mouth. How Dry Mouth Feels Dry mouth can be uncomfortable. Some people ...

  11. Ester-Mediated Amide Bond Formation Driven by Wet-Dry Cycles: A Possible Path to Polypeptides on the Prebiotic Earth.

    PubMed

    Forsythe, Jay G; Yu, Sheng-Sheng; Mamajanov, Irena; Grover, Martha A; Krishnamurthy, Ramanarayanan; Fernández, Facundo M; Hud, Nicholas V

    2015-08-17

    Although it is generally accepted that amino acids were present on the prebiotic Earth, the mechanism by which α-amino acids were condensed into polypeptides before the emergence of enzymes remains unsolved. Here, we demonstrate a prebiotically plausible mechanism for peptide (amide) bond formation that is enabled by α-hydroxy acids, which were likely present along with amino acids on the early Earth. Together, α-hydroxy acids and α-amino acids form depsipeptides-oligomers with a combination of ester and amide linkages-in model prebiotic reactions that are driven by wet-cool/dry-hot cycles. Through a combination of ester-amide bond exchange and ester bond hydrolysis, depsipeptides are enriched with amino acids over time. These results support a long-standing hypothesis that peptides might have arisen from ester-based precursors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Microbial mediated soil structure formation under wetting and drying cycles along a climate gradient (arid to humid) on hillslopes in Chile

    NASA Astrophysics Data System (ADS)

    Bernhard, Nadine; Moskwa, Lisa-Marie; Kühn, Peter; Mueller, Carsten W.; Wagner, Dirk; Scholten, Thomas

    2017-04-01

    It is well-known that the land surface resistance against erosion is largely controlled by the structure stability of the soil given by its inherent properties. Microbial activity plays a vital role in soil structure development, and thus affecting soil physical parameters. Accordingly the influence of biota shaping the earth's surface has been described through mechanisms such as mineral weathering, formation of ions and biofilms controlling land surface resistance against erosion. However the role of microorganisms for the development of soil stabilizing properties is still unclear and a precise quantitative understanding of the mechanisms under different climate conditions is widely missing. The objectives of our study are to examine to which extend microbiological processes control soil structure formation and stability and whether this is influenced by climate and topographic position. Soil samples were taken along a climate gradient and from different topographic positions of hillslopes in the Chilean Coastal Cordillera in austral autumn 2016. The variables of lithology, human disturbances and relief were held as far as possible constant whereas climate varies along the transect. We implemented 10 wet-dry cycles on air dried and sieved natural and sterile samples to enhance particle aggregation and increase structure stability. Throughout the entire experiment temperature is held constant at 20 °C to avoid changes in microbial activity. Samples are moistened and dried and each kept at the same respective pF-values for the same duration to add the same stress to each sample. Aggregate stability will be measured using wet sieving, ultrasonic dispersion and simulated rainfall. The results will be compared with on-site rainfall simulation experiments on hillslopes in the Chilean Coastal Cordillera to link laboratory results with natural field conditions. The experiment gives first insight into the aggregate formation process over time with and without

  13. Suspended sediment transport in the Deepwater Navigation Channel, Yangtze River Estuary, China, in the dry season 2009: 1. Observations over spring and neap tidal cycles

    NASA Astrophysics Data System (ADS)

    Song, Dehai; Wang, Xiao Hua; Cao, Zhenyi; Guan, Weibing

    2013-10-01

    The in situ data in the Deepwater Navigation Channel (DNC), Yangtze River Estuary (YRE), China, in the dry season 2009, shows spring tides associated with greater maximum velocities, more mixing, less stratification, and diffused fluid mud; whereas neap tides are associated with smaller maximum velocities, greater stratification, inhibited mixing, and stratified fluid muds. The balance of salt flux indicates the seaward salt transport is dominated by fluvial flows, and the landward salt transport is generated by compensation flows during spring tides, but shear effects during neap tidal cycles. The balance of suspended sediment flux illustrates the offshore sediment transport is dominated by fluvial flows as well, but the onshore transport is induced by tidal-pumping effects on spring tides, and shear effects on neaps. The suspended sediment transport is strongly affected by the salinity distribution and salinity-gradient-induced stratification in the DNC. The spring-neap asymmetry is generated by the estuarine gravitational circulation during low-flow conditions; while the flood-ebb asymmetric stratification within a tidal cycle is due to the semidiurnal tidally movement of the salt front.

  14. Wetting and drying cycles drive variations in the stable carbon isotope ratio of respired carbon dioxide in semi-arid grassland.

    PubMed

    Shim, Jee H; Pendall, Elise; Morgan, Jack A; Ojima, Dennis S

    2009-05-01

    In semi-arid regions, where plants using both C(3) and C(4) photosynthetic pathways are common, the stable C isotope ratio (delta(13)C) of ecosystem respiration (delta(13)C(R)) is strongly variable seasonally and inter-annually. Improved understanding of physiological and environmental controls over these variations will improve C cycle models that rely on the isotopic composition of atmospheric CO(2). We hypothesized that timing of precipitation events and antecedent moisture interact with activity of C(3) and C(4) grasses to determine net ecosystem CO(2) exchange (NEE) and delta(13)C(R). Field measurements included CO(2) and delta(13)C fluxes from the whole ecosystem and from patches of different plant communities, biomass and delta(13)C of plants and soils over the 2000 and 2001 growing seasons. NEE shifted from C source to sink in response to rainfall events, but this shift occurred after a time lag of up to 2 weeks if a dry period preceded the rainfall. The seasonal average of delta(13)C(R) was higher in 2000 (-16 per thousand) than 2001 (20 per thousand), probably due to drier conditions during the 2000 growing season (79.7 mm of precipitation from April up to and including July) than in 2001 (189 mm). During moist conditions, delta(13)C averaged -22 per thousand from C(3) patches, -16 per thousand from C(4) patches, and -19 per thousand from mixed C(3) and C(4) patches. However, during dry conditions the apparent spatial differences were not obvious, suggesting reduced autotrophic activity in C(4) grasses with shallow rooting depth, soon after the onset of dry conditions. Air and soil temperatures were negatively correlated with delta(13)C(R); vapor pressure deficit was a poor predictor of delta(13)C(R), in contrast to more mesic ecosystems. Responses of respiration components to precipitation pulses were explained by differences in soil moisture thresholds between C(3) and C(4) species. Stable isotopic composition of respiration in semi-arid ecosystems is

  15. Interactive effects of distillers dried grains with solubles and housing system on reproductive performance and longevity of sows over three reproductive cycles.

    PubMed

    Li, X; Baidoo, S K; Li, Y Z; Shurson, G C; Johnston, L J

    2014-04-01

    An experiment was conducted to evaluate the interactive effects of dietary distillers dried grains with solubles (DDGS) in sow diets and housing systems on reproductive performance and longevity. Sows (311 for parity 0 and 90 for parity 1) were assigned randomly within parity to 1 of 4 treatments and maintained on these treatments for up to 3 reproductive cycles. Sows were fed either fortified corn-soybean meal control diets (CON) during gestation and lactation or diets containing 40% DDGS in gestation and 20% DDGS in lactation and were housed either in individual stalls or group pens with electronic sow feeders during gestation. Sows fed DDGS had smaller (P < 0.05) litter size (born alive, 11.0 vs. 11.6; weaning, 9.8 vs. 10.2) and had more (P < 0.05) stillborns (0.9 vs. 0.7) than sows fed CON. Litters nursing sows fed DDGS gained less weight (P < 0.01) than litters nursing sows fed CON (47.8 vs. 49.8 kg, respectively). Group-housed sows tended to farrow smaller litters (born alive, 11.0 vs. 11.5; P < 0.10) and had fewer pigs at weaning (9.9 vs. 10.2; P < 0.05) compared with stall-housed sows. Litters from group-housed sows tended (P < 0.10) to gain less weight while suckling than those from stall-housed sows (48.3 vs. 49.4 kg, respectively). Diet did not affect the percentage of sows that completed each successive reproductive cycle. Stall housing tended to increase (P = 0.06) the completion rate of sows at the second reproductive cycle (80.0 vs. 68.2%) and increased (P < 0.05) the completion rate of sows in the third reproductive cycle (68.9 vs. 55.8%) compared with group housing. Sows fed DDGS produced fewer (P < 0.05) live-born pigs (26.2 vs. 27.4) and tended (P < 0.10) to have fewer pigs weaned (23.7 vs. 24.5) over 3 reproductive cycles compared with sows fed CON. Stall-housed sows farrowed more (P < 0.05) total pigs (30.1 vs. 26.7) and live pigs (28.4 vs. 25.2) and had more weaned pigs (25.2 vs. 23.1) compared with group-housed sows over 3 reproductive cycles

  16. Decoupled responses of soil bacteria and their invertebrate consumer to warming, but not freeze-thaw cycles, in the Antarctic Dry Valleys.

    PubMed

    Knox, Matthew A; Andriuzzi, Walter S; Buelow, Heather N; Takacs-Vesbach, Cristina; Adams, Byron J; Wall, Diana H

    2017-10-01

    Altered temperature profiles resulting in increased warming and freeze-thaw cycle (FTC) frequency pose great ecological challenges to organisms in alpine and polar ecosystems. We performed a laboratory microcosm experiment to investigate how temperature variability affects soil bacterial cell numbers, and abundance and traits of soil microfauna (the microbivorous nematode Scottnema lindsayae) from McMurdo Dry Valleys, Antarctica. FTCs and constant freezing shifted nematode body size distribution towards large individuals, driven by higher mortality among smaller individuals. FTCs reduced both bacterial and nematode abundance, but bacterial cell numbers also declined under warming, demonstrating decoupled consumer-prey responses. We predict that higher occurrence of FTCs in cold ecosystems will select for large body size within soil microinvertebrates and overall reduce their abundance. In contrast, warm temperatures without FTCs could lead to divergent responses in soil bacteria and their microinvertebrate consumers, potentially affecting energy and nutrient transfer rates in soil food webs of cold ecosystems. © 2017 John Wiley & Sons Ltd/CNRS.

  17. Biochar influences on soil CO2 and CH4 fluxes in response to wetting and drying cycles for a forest soil.

    PubMed

    Johnson, Mark S; Webster, Cameron; Jassal, Rachhpal S; Hawthorne, Iain; Black, T Andrew

    2017-07-28

    Biochar has been the focus of significant research efforts in agriculture, but little research has been conducted in forested ecosystems. Here, we assess CO2 and CH4 fluxes from a forest soil in response to biochar additions using a before-after-control-intervention experimental design. Soil CO2 and CH4 fluxes were measured over a series of wetting cycles by coupling soil mesocosms equipped with auto-chambers to a laser-based spectrometer for high-frequency measurements of gas fluxes and related soil processes. We found that soil CO2 fluxes were higher and CH4 fluxes were less negative (e.g. reduced CH4 uptake) for the biochar-amended soil compared to the no biochar condition. Furthermore, biochar improved soil infiltrability under wet conditions, and enhanced soil moisture levels under dry conditions. Biochar additions shifted the point of maximum soil respiration (i.e. soil CO2 efflux) to a slightly wetter soil moisture level. The point of maximum CH4 uptake was also shifted to a slightly wetter moisture level for soil with biochar. Overall differences in soil gas fluxes were found to be minor compared to the increase in soil carbon resulting from the biochar addition. Biochar may thus contribute to improved forest management through increases to soil carbon stocks and improved soil moisture levels.

  18. [Nutrient accumulation and cycling in pure and mixed plantations of Azadirachta indica and Acacia auriculiformis in a dry-hot valley, Yunnan Province, southwest China].

    PubMed

    Gao, Cheng-Jie; Li, Kun; Tang, Guo-Yong; Zhang, Chun-Hua; Li, Bin

    2014-07-01

    To ease the implementation of effective nutrient management for plantations with different vegetation restoration patterns and to assist in the selection of appropriate species and forestation patterns, nutrient (N, P, K, Ca and Mg) accumulation and cycling were investigated and compared in three plantations (10-year-old Azadirachta indica, Acacia auriculiformis and mixed A. indica--A. auriculiformis plantations) in Yuanmou Valley, a dry-hot valley of Yunnan Province, Southwestern China. The result showed that total nutrient accumulations were 333.05, 725.61 and 533.85 kg x hm(-2) in pure plantations of A. indica and A. auriculiformis, and in A. indica--A. auriculiformis mixed plantation, respectively. The nutrient accumulation of various organs was ranked as branches > stems > roots > leaves > bark in the A. indica plantation and branches > stems > leaves > roots > bark both in the A. auriculiformis plantation and in the mixed plantation. Changes in accumulation of various nutrients in the mixed plantation were similar to that in the A. auriculiformis plantation (Ca > N > K > Mg > P), which were different from the A. indica plantation (Ca > K > N > Mg > P). Annual net nutrient accumulation, return and absorption in these plantations ranged from 62.72 to 162.19 kg x hm(-2) x a(-1), 48.82 to 88.86 kg x hm-2 a-1 and 111.54 to 251.05 kg x hm(-2) x a(-1), respectively, which were all the highest in the A. auriculiformis planta- tion, followed by the mixed plantation, and were the lowest in the A. indica plantation. The nutrient utilization coefficient, the cycling coefficient and the recycling period were estimated to be from 0.34 to 0.39, 0.35 to 0.44, and 6.54 to 8.17 a, respectively. The lower nutrient return and circulation rate of N or P in the A. indica plantation showed that this plantation had a poor ability to maintain soil fertility, while the highest nutrient circulation rate of N or P was observed in the A. auriculiformis plantation that displayed the

  19. Dry Mouth

    MedlinePlus

    Dry mouth is the feeling that there is not enough saliva in your mouth. Everyone has a dry mouth once in a while - if they are nervous, ... under stress. But if you have a dry mouth all or most of the time, it can ...

  20. A New Analysis Method of the Dry Sliding Wear Process Based on the Low Cycle Fatigue Theory and the Finite Element Method

    NASA Astrophysics Data System (ADS)

    Abdi, Mohammad; Taheri, Ali Karimi; Bakhtiarydavijani, Amirhamed

    2014-03-01

    In the present work, a combination of a dynamic explicit finite element model and the low cycle fatigue theory is used to simulate the steady-state abrasive wear occurring between an as-cast eutectoid steel and a carbide-tungsten disk. While the low cycle fatigue theory has been used to model wear in softer non-ferrous alloys, this work shows its applicability and accuracy for use in harder alloys, such as the eutectoid steel used in this research which is strengthened with added chromium. The novelty of this work lies in calculating the Manson-Coffin relation constants from a coupled finite element model with experimental tests instead of the previously used Slip line method. The D Manson-Coffin constant, obtained around 2, is in agreement with previous works given in the literature showing that the low cycle fatigue is a general wear mechanism in the steady-state wear of the alloy tested in this work.

  1. Assessment of a combined dry anaerobic digestion and post-composting treatment facility for source-separated organic household waste, using material and substance flow analysis and life cycle inventory.

    PubMed

    Jensen, Morten Bang; Møller, Jacob; Scheutz, Charlotte

    2017-08-01

    The fate of total solids, volatile solids, total organic carbon, fossil carbon, biogenic carbon and 17 substances (As, Ca, CaCO3, Cd, Cl, Cr, Cu, H, Hg, K, Mg, N, Ni, O, P, Pb, S, Zn) in a combined dry anaerobic digestion and post-composting facility were assessed. Mass balances showed good results with low uncertainties for non-volatile substances, while balances for nitrogen, carbon, volatile solids and total organic carbon showed larger but reasonable uncertainties, due to volatilisation and emissions into the air. Material and substance flow analyses were performed in order to obtain transfer coefficients for a combined dry anaerobic digestion and post-composting facility. All metals passed through the facility and ended up in compost or residues, but all concentrations of metals in the compost complied with legislation. About 23% of the carbon content of the organic waste was transferred to the biogas, 24% to the compost, 13% to residues and 40% into the atmosphere. For nitrogen, 69% was transferred to the compost, 10% volatilised to the biofilter, 11% directly into the atmosphere and 10% to residues. Finally, a full life cycle inventory was conducted for the combined dry anaerobic digestion and post-composting facility, including waste received, fuel consumption, energy use, gaseous emissions, products, energy production and chemical composition of the compost produced. Copyright © 2017. Published by Elsevier Ltd.

  2. Soil dehydrogenase in a land degradation-rehabilitation gradient: observations from a savanna site with a wet/dry seasonal cycle.

    PubMed

    Doi, Ryoichi; Ranamukhaarachchi, Senaratne Leelananda

    2009-01-01

    Soil dehydrogenase activity is a good indicator of overall microbial activity in soil, and it can serve as a good indicator of soil condition. However, seasonal changes in soil moisture content may have an effect on soil dehydrogenase activity, making an accurate assessment of soil condition difficult. In this study, we attempted to determine the significance of soil dehydrogenase activity for assessing soil condition, and we attempted to find a way to account for the influence of soil moisture content on soil dehydrogenase activity.' Soils were sampled in dry evergreen forest (original vegetation), bare ground (severely degraded) and Acacia plantation plots established on bare ground in 1986 and 1987 in Sakaerat, Thailand. Soil physico-chemical characteristics and dehydrogenase activity in the Acacia plantation soil had few differences from those in the evergreen forest soil. Soil dehydrogenase activity varied significantly between the bare ground and the forests regardless of the season (wet or dry), while the season did not produce a significant variation in soil dehydrogenase activity, as determined by repeated measures analysis of variance (p=0.077). The physico-chemical data provided the first principal component as a good measure of soil fertility. Values of soil dehydrogenase activity significantly correlated to scores of the soil samples of the first principal component (R=0.787, p<0.001). We found that soil dehydrogenase activity is a useful indicator of the extent of soil degradation and the rehabilitative effects of reforestation in this part of Thailand.

  3. Dry Matter Production, Nutrient Cycled and Removed, and Soil Fertility Changes in Yam-Based Cropping Systems with Herbaceous Legumes in the Guinea-Sudan Zone of Benin.

    PubMed

    Maliki, Raphiou; Sinsin, Brice; Floquet, Anne; Cornet, Denis; Malezieux, Eric; Vernier, Philippe

    2016-01-01

    Traditional yam-based cropping systems (shifting cultivation, slash-and-burn, and short fallow) often result in deforestation and soil nutrient depletion. The objective of this study was to determine the impact of yam-based systems with herbaceous legumes on dry matter (DM) production (tubers, shoots), nutrients removed and recycled, and the soil fertility changes. We compared smallholders' traditional systems (1-year fallow of Andropogon gayanus-yam rotation, maize-yam rotation) with yam-based systems integrated herbaceous legumes (Aeschynomene histrix/maize intercropping-yam rotation, Mucuna pruriens/maize intercropping-yam rotation). The experiment was conducted during the 2002 and 2004 cropping seasons with 32 farmers, eight in each site. For each of them, a randomized complete block design with four treatments and four replicates was carried out using a partial nested model with five factors: Year, Replicate, Farmer, Site, and Treatment. Analysis of variance (ANOVA) using the general linear model (GLM) procedure was applied to the dry matter (DM) production (tubers, shoots), nutrient contribution to the systems, and soil properties at depths 0-10 and 10-20 cm. DM removed and recycled, total N, P, and K recycled or removed, and soil chemical properties (SOM, N, P, K, and pH water) were significantly improved on yam-based systems with legumes in comparison with traditional systems.

  4. Dry Matter Production, Nutrient Cycled and Removed, and Soil Fertility Changes in Yam-Based Cropping Systems with Herbaceous Legumes in the Guinea-Sudan Zone of Benin

    PubMed Central

    Sinsin, Brice; Floquet, Anne; Cornet, Denis; Malezieux, Eric; Vernier, Philippe

    2016-01-01

    Traditional yam-based cropping systems (shifting cultivation, slash-and-burn, and short fallow) often result in deforestation and soil nutrient depletion. The objective of this study was to determine the impact of yam-based systems with herbaceous legumes on dry matter (DM) production (tubers, shoots), nutrients removed and recycled, and the soil fertility changes. We compared smallholders' traditional systems (1-year fallow of Andropogon gayanus-yam rotation, maize-yam rotation) with yam-based systems integrated herbaceous legumes (Aeschynomene histrix/maize intercropping-yam rotation, Mucuna pruriens/maize intercropping-yam rotation). The experiment was conducted during the 2002 and 2004 cropping seasons with 32 farmers, eight in each site. For each of them, a randomized complete block design with four treatments and four replicates was carried out using a partial nested model with five factors: Year, Replicate, Farmer, Site, and Treatment. Analysis of variance (ANOVA) using the general linear model (GLM) procedure was applied to the dry matter (DM) production (tubers, shoots), nutrient contribution to the systems, and soil properties at depths 0–10 and 10–20 cm. DM removed and recycled, total N, P, and K recycled or removed, and soil chemical properties (SOM, N, P, K, and pH water) were significantly improved on yam-based systems with legumes in comparison with traditional systems. PMID:27446635

  5. Use of a sub-gasket and soft gas diffusion layer to mitigate mechanical degradation of a hydrocarbon membrane for polymer electrolyte fuel cells in wet-dry cycling

    NASA Astrophysics Data System (ADS)

    Ishikawa, Hiroshi; Teramoto, Takeshi; Ueyama, Yasuhiro; Sugawara, Yasushi; Sakiyama, Yoko; Kusakabe, Masato; Miyatake, Kenji; Uchida, Makoto

    2016-09-01

    The mechanical durability of hydrocarbon (HC) membranes, used for polymer electrolyte fuel cells (PEFCs), was evaluated by the United States Department of Energy (USDOE) stress protocol involving wet-dry cycling, and the degradation mechanism is discussed. The HC membrane ruptured in the edge region of the membrane electrode assembly (MEA) after 300 cycles due to a concentration of the mechanical stress. Post-test analysis of stress-strain measurements revealed that the membrane mechanical strain decreased more than 80% in the edge region of the MEA and about 50% in the electrode region, compared with the pristine condition. Size exclusion chromatography (SEC) indicated that the average molecular weight of the HC polymer increased slightly, indicating some cross-linking, while the IEC decreased slightly, indicating ionomer degradation. As a result of two types of modifications, a sub-gasket (SG) and a soft gas diffusion layer (GDL) in the MEA edge region, the mechanical stress decreased, and the durability increased, the membrane lasting more than 30,000 cycles without mechanical failure.

  6. Dry Mouth

    MedlinePlus

    ... protect your teeth may also help your dry mouth condition: Brush with a fluoride toothpaste and floss your teeth. Ask your dentist ... acids. Use a fluoride rinse or brush-on fluoride gel before ... historically to treat dry mouth, such as teas made from marshmallow or slippery ...

  7. Peat porewater chloride concentration profiles in the Everglades during wet/dry cycles from January 1996 to June 1998: Field measurements and theoretical analysis

    USGS Publications Warehouse

    Reddy, M.M.; Reddy, M.B.; Kipp, K.L.; Burman, A.; Schuster, P.; Rawlik, P.S.

    2008-01-01

    Water quality is a key aspect of the Everglades Restoration Project, the largest water reclamation and ecosystem management project proposed in the United States. Movement of nutrients and contaminants to and from Everglades peat porewater could have important consequences for Everglades water quality and ecosystem restoration activities. In a study of Everglades porewater, we observed complex, seasonally variable peat porewater chloride concentration profiles at several locations. Analyses and interpretation of these changing peat porewater chloride concentration profiles identifies processes controlling conservative solute movement at the peat-surface water interface, that is, solutes whose transport is minimally affected by chemical and biological reactions. We examine, with an advection-diffusion model, how alternating wet and dry climatic conditions in the Florida Everglades mediate movement of chloride between peat porewater and marsh surface water. Changing surface water-chloride concentrations alter gradients at the interface between peat and overlying water and hence alter chloride flux across that interface. Surface water chloride concentrations at two frequently monitored sites vary with marsh water depth, and a transfer function was developed to describe daily marsh surface water chloride concentration as a function of marsh water depth. Model results demonstrate that porewater chloride concentrations are driven by changing surface water chloride concentrations, and a sensitivity analysis suggests that inclusion of advective transport in the model improves the agreement between the calculated and the observed chloride concentration profiles. Copyright ?? 2007 John Wiley & Sons, Ltd.

  8. Ester-Mediated Amide Bond Formation Driven by Wet–Dry Cycles: A Possible Path to Polypeptides on the Prebiotic Earth**

    PubMed Central

    Forsythe, Jay G; Yu, Sheng-Sheng; Mamajanov, Irena; Grover, Martha A; Krishnamurthy, Ramanarayanan; Fernández, Facundo M; Hud, Nicholas V

    2015-01-01

    Although it is generally accepted that amino acids were present on the prebiotic Earth, the mechanism by which α-amino acids were condensed into polypeptides before the emergence of enzymes remains unsolved. Here, we demonstrate a prebiotically plausible mechanism for peptide (amide) bond formation that is enabled by α-hydroxy acids, which were likely present along with amino acids on the early Earth. Together, α-hydroxy acids and α-amino acids form depsipeptides—oligomers with a combination of ester and amide linkages—in model prebiotic reactions that are driven by wet–cool/dry–hot cycles. Through a combination of ester–amide bond exchange and ester bond hydrolysis, depsipeptides are enriched with amino acids over time. These results support a long-standing hypothesis that peptides might have arisen from ester-based precursors. PMID:26201989

  9. Process-based modeling of coupled energy and water cycle under dry tropical conditions: an experiment at local scale in the cultivated Sahel (South-West Niger)

    NASA Astrophysics Data System (ADS)

    Velluet, C.; Demarty, J.; Cappelaere, B.; Braud, I.; Boulain, N.; Charvet, G.; Chazarin, J.-P.; Mainassara, I.; Boucher, M.; Issoufou, H. B.-A.; Ibrahim, M.; Oi, M.; Ramier, D.; Benarrosh, N.; Yahou, H.

    2012-04-01

    In the dry tropics in general and, particularly in the African Sahel, agro-ecosystems and hydrosystems are very sensitive to climate variability and land management. In turn, it has been shown that soil moisture, vegetation and surface fluxes produce substantial feedback effects on rainfall-producing atmospheric convection. Therefore, it is of prime importance to understand and to model the dynamics of the soil-plant-atmosphere continuum in response to contrasted meteorological and terrestrial conditions for this area. The objective of this study is to produce a process-based model of water and energy transfers in the soil and land-atmosphere interface over an entire 5-year period, at local scale, for the two main land cover types of South-West Niger: millet-crop and fallow savannah. A comprehensive dataset is available over that whole period in two such fields of the Wankama catchment, making it a rather unique asset for West Africa. This area is typical of the central Sahel conditions, with ~400-600 mm annual rainfall concentrated in the 4-5 months wet season, followed by the 7-8 months dry season. Soils are essentially sandy and prone to surface crusting, which induces a strong vertical contrast in hydrodynamic properties. The dataset used here includes 5 years of atmospheric forcing (rainfall, wind speed, sun and atmosphere radiation, air temperature and moisture) and validation variables (net radiation, turbulent fluxes and soil temperature and moisture profiles), recorded every 30 min. The seasonal course of vegetation phenology (LAI, height, biomass) and soil characteristics (particle size and density profiles) are also available. The SiSPAT (Simple Soil-Plant-Atmosphere Transfer, Braud et al., 1995) physically-based model is used for this study. It solves the mass and heat transfer system of equations in the soil, with vapour phase, coupled with a two-component (bare soil and one vegetation layer) water and energy budget at the surface-atmosphere interface

  10. century drying

    NASA Astrophysics Data System (ADS)

    Cook, Benjamin I.; Smerdon, Jason E.; Seager, Richard; Coats, Sloan

    2014-11-01

    Global warming is expected to increase the frequency and intensity of droughts in the twenty-first century, but the relative contributions from changes in moisture supply (precipitation) versus evaporative demand (potential evapotranspiration; PET) have not been comprehensively assessed. Using output from a suite of general circulation model (GCM) simulations from phase 5 of the Coupled Model Intercomparison Project, projected twenty-first century drying and wetting trends are investigated using two offline indices of surface moisture balance: the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Evapotranspiration Index (SPEI). PDSI and SPEI projections using precipitation and Penman-Monteith based PET changes from the GCMs generally agree, showing robust cross-model drying in western North America, Central America, the Mediterranean, southern Africa, and the Amazon and robust wetting occurring in the Northern Hemisphere high latitudes and east Africa (PDSI only). The SPEI is more sensitive to PET changes than the PDSI, especially in arid regions such as the Sahara and Middle East. Regional drying and wetting patterns largely mirror the spatially heterogeneous response of precipitation in the models, although drying in the PDSI and SPEI calculations extends beyond the regions of reduced precipitation. This expansion of drying areas is attributed to globally widespread increases in PET, caused by increases in surface net radiation and the vapor pressure deficit. Increased PET not only intensifies drying in areas where precipitation is already reduced, it also drives areas into drought that would otherwise experience little drying or even wetting from precipitation trends alone. This PET amplification effect is largest in the Northern Hemisphere mid-latitudes, and is especially pronounced in western North America, Europe, and southeast China. Compared to PDSI projections using precipitation changes only, the projections incorporating both

  11. Chemical Engineering Division fuel cycle programs. Quarterly progress report, April-June 1979. [Pyrochemical/dry processing; waste encapsulation in metal; transport in geologic media

    SciTech Connect

    Steindler, M.J.; Ader, M.; Barletta, R.E.

    1980-09-01

    For pyrochemical and dry processing materials development included exposure to molten metal and salt of Mo-0.5% Ti-0.07% Ti-0.01% C, Mo-30% W, SiC, Si/sub 2/ON/sub 2/, ZrB/sub 2/-SiC, MgAl/sub 2/O/sub 4/, Al/sub 2/O/sub 3/, AlN, HfB/sub 2/, Y/sub 2/O/sub 3/, BeO, Si/sub 3/N/sub 4/, nickel nitrate-infiltrated W, W-coated Mo, and W-metallized alumina-yttria. Work on Th-U salt transport processing included solubility of Th in liquid Cd, defining the Cd-Th and Cd-Mg-Th phase diagrams, ThO/sub 2/ reduction experiments, and electrolysis of CaO in molten salt. Work on pyrochemical processes and associated hardware for coprocessing U and Pu in spent FBR fuels included a second-generation computer model of the transport process, turntable transport process design, work on the U-Cu-Mg system, and U and Pu distribution coefficients between molten salt and metal. Refractory metal vessels are being service-life tested. The chloride volatility processing of Th-based fuel was evaluated for its proliferation resistance, and a preliminary ternary phase diagram for the Zn-U-Pu system was computed. Material characterization and process analysis were conducted on the Exportable Pyrochemical process (Pyro-Civex process). Literature data on oxidation of fissile metals to oxides were reviewed. Work was done on chemical bases for the reprocessing of actinide oxides in molten salts. Flowsheets are being developed for the processing of fuel in molten tin. Work on encapsulation of solidified radioactive waste in metal matrix included studies of leach rate of crystalline waste materials and of the impact resistance of metal-matrix waste forms. In work on the transport properties of nuclear waste in geologic media, adsorption of Sr on oolitic limestone was studied, as well as the migration of Cs in basalt. Fitting of data on the adsorption of iodate by hematite to a mathematical model was attempted.

  12. Colorful drying.

    PubMed

    Lakio, Satu; Heinämäki, Jyrki; Yliruusi, Jouko

    2010-03-01

    Drying is one of the standard unit operations in the pharmaceutical industry and it is important to become aware of the circumstances that dominate during the process. The purpose of this study was to test microcapsulated thermochromic pigments as heat indicators in a fluid bed drying process. The indicator powders were manually granulated with alpha-lactose monohydrate resulting in three particle-size groups. Also, pellets were coated with the indicator powders. The granules and pellets were fluidized in fluid bed dryer to observe the progress of the heat flow in the material and to study the heat indicator properties of the indicator materials. A tristimulus colorimeter was used to measure CIELAB color values. Color indicator for heat detection can be utilized to test if the heat-sensitive API would go through physical changes during the pharmaceutical drying process. Both the prepared granules and pellets can be used as heat indicator in fluid bed drying process. The colored heat indicators give an opportunity to learn new aspects of the process at real time and could be exploded, for example, for scaling-up studies.

  13. Carbon, nitrogen cycling and land cover changes during regrowth in African dry tropical forests: integrating perspectives from field and satellite data across a chronosequence in the Miombo Woodlands of western Tanzania

    NASA Astrophysics Data System (ADS)

    Mayes, M. T.; Melillo, J. M.; Mustard, J. F.; Neill, C.; Nyadzi, G.

    2015-12-01

    Seasonally dry tropical forests in Africa (SDTFs), such as forests in Miombo Woodlands, are experiencing high rates of deforestation, degradation and regrowth. Increasing proportions of forest are disturbed or composed of young regrowth stands (<40 yr), yet the degree and dynamics of how forest structure, biogeochemical and hydrological cycling recover with regrowth are poorly understood. Here, we examine how forest structure, carbon (C) and nitrogen (N) cycling change with regrowth following cultivation in forests of western Tanzania's Miombo. This work addresses 3 questions: (1) What are the timescales of aboveground tree C stock recovery and patterns of soil mineral N availability with regrowth; (2) How does N demand for tree leaf production compare to indicators of available mineral N in surface soils from young to mature forest sites; (3) How does canopy structure vary with regrowth and disturbance and scale to Landsat-style satellite data? We established a chronosequence of 18 sites with ages 3 to >40 years since abandonment. At each, we inventoried trees to quantify aboveground tree C stocks, sampled soils to 100 cm to measure C, total and mineral N (NH4+, NO3-), and surveyed canopy cover with point-line transects, spherical densiometer and photometric leaf area measures. We also conducted soil incubations to determine nitrogen mineralization potentials. Tree C stocks ranged from 0.4 ± 0.1 Mg C ha-1 for 3-4 year sites to 27.2 ± 5.2 Mg C ha-1 for 30-40 year sites, and were 44.5 ± 7.4 Mg C ha-1 for mature forest sites. Rates of aboveground tree C stock changes (0.78 - 0.89 Mg C ha-1 yr-1) were comparable to the few published for Miombo forests. However, tree C stocks at 10 - 24 year sites (5.2 ± 1.1 Mg C ha -1) were much lower than those reported in comparable studies. Only sites > 30-40 years had C stocks approaching mature forests. Further analyses will compare N dynamics from leaves and soil across the chronosequence, and relate them to the trends in

  14. Drying rates of wood chips during compression drying

    SciTech Connect

    Liu, Z.; Haygreen, J.G.

    1985-04-01

    Compression drying is basically a process of forcing the free water in wood to move under high hydrostatic pressure through a solid structure. Fundamental information regarding the time- dependent characteristic of compression drying is necessary to develop efficient commercial processes. The purpose of this study is to provide an initial evaluation of the effect of some factors - pressure, wood density, and particle (chip) size - on free water extraction. Five species - aspen, balsam fir, jack pine, red maple, and red oak - were tested in this study. For each species both typical pulp size chips and particles from hammermilled chips were used. Drying rates were determined under constant ram face pressures at 500 psi, 1000 psi, 1500 psi, and 2000 psi, respectively. The concept of drying rate is one of the important factors in dealing with compression drying, especially in designing dewatering pressure cycles. The most efficient compression drying is achieved during the first two minutes. Drying rates are negligible after 3 to 4 minutes of constant pressure in the 500 to 2000 psi range. The analysis of variance for species shows highly significant differences in final moisture contents. Size of chips had a significant effect on final moisture contents. Compressed density of hammermilled chips is slightly higher than that of unrefined chips. High density chips require higher pressure to initiate effective drying rates. 8 references.

  15. Drying Thermoplastics

    NASA Technical Reports Server (NTRS)

    1976-01-01

    In searching for an improved method of removing water from polyester type resins without damaging the materials, Conair Inc. turned to the NASA Center at the University of Pittsburgh for assistance. Taking an organized, thorough look at existing technology before beginning research has helped many companies save significant time and money. They searched the NASA and other computerized files for microwave drying of thermoplastics. About 300 relevant citations were retrieved - eight of which were identified as directly applicable to the problem. Company estimates it saved a minimum of a full year in compiling research results assembled by the information center.

  16. Dry cell battery poisoning

    MedlinePlus

    Acidic dry cell batteries contain: Manganese dioxide Ammonium chloride Alkaline dry cell batteries contain: Sodium hydroxide Potassium hydroxide Lithium dioxide dry cell batteries contain: Manganese dioxide

  17. Infrared Drying Parameter Optimization

    NASA Astrophysics Data System (ADS)

    Jackson, Matthew R.

    control system to ensure that prints continuously dry the same way. In addition to the repeatability study, experimenting with the feasibility of using single pass prints with repeatable performance would also be a worthwhile study. A single print pass will reduce cycle time, and will reduce ink consumption when compared with double pass prints.

  18. Magnetic field switchable dry adhesives.

    PubMed

    Krahn, Jeffrey; Bovero, Enrico; Menon, Carlo

    2015-02-04

    A magnetic field controllable dry adhesive device is manufactured. The normal adhesion force can be increased or decreased depending on the presence of an applied magnetic field. If the magnetic field is present during the entire normal adhesion test cycle which includes both applying a preloading force and measuring the pulloff pressure, a decrease in adhesion is observed when compared to when there is no applied magnetic field. Similarly, if the magnetic field is present only during the preload portion of the normal adhesion test cycle, a decrease in adhesion is observed because of an increased stiffness of the magnetically controlled dry adhesive device. When the applied magnetic field is present during only the pulloff portion of the normal adhesion test cycle, either an increase or a decrease in normal adhesion is observed depending on the direction of the applied magnetic field.

  19. Drying hardwood lumber

    Treesearch

    Joseph. Denig; Eugene M. Wengert; William T. Simpson

    2000-01-01

    Drying Hardwood Lumber focuses on common methods for drying lumber of different thickness, with minimal drying defects, for high quality applications. This manual also includes predrying treatments that, when part of an overall quality-oriented drying system, reduce defects and improve drying quality, especially of oak lumber. Special attention is given to drying white...

  20. Solar drying in the Caribbean

    SciTech Connect

    Headley, O. )

    1992-03-01

    The United Nations Food and Agricultural Organisation (FAO) has estimated that a quarter of crops are lost through inadequate handling after harvesting. The use of solar dryers can reduce these losses and improve the quality of food. Oliver Headley of the University of the West Indies overviews a range of dryers developed in the Caribbean region. Solar dryers have been used in various parts of the Caribbean for the past eighteen years. The main types are: closed cycle dryers with separate flat plate collector; open cycle dryers with roof vanes against direct sunlight; open cycle dryers with rockbed heat storage units; open cycle dryers with chimneys for air circulation; wire basket dryers with flow through ventilation; barn roof collectors feeding packed bed dryers. During the dry season (January to April), mean daily insolation in a typical Caribbean island is about 25 MJ/m{sup 2}. With such an abundant resource, solar crop drying emerged as a preferred method for the preservation of perishable commodities. In territories without fossil fuel reserves solar energy is an obvious alternative since it does not involve expenditure of scarce foreign exchange. Research and development work in solar crop drying was conducted both at experimental sites in the University and in rural districts throughout the region. Several types of dryer were designed and tested.

  1. Gas storage in "dry water" and "dry gel" clathrates.

    PubMed

    Carter, Benjamin O; Wang, Weixing; Adams, Dave J; Cooper, Andrew I

    2010-03-02

    "Dry water" (DW) is a free-flowing powder prepared by mixing water, hydrophobic silica particles, and air at high speeds. We demonstrated recently that DW can be used to dramatically enhance methane uptake rates in methane gas hydrate (MGH). Here, we expand on our initial work, demonstrating that DW can be used to increase the kinetics of formation of gas clathrates for gases other than methane, such as CO(2) and Kr. We also show that the stability of the system toward coalescence can be increased via the inclusion of a gelling agent to form a "dry gel", thus dramatically improving the recyclability of the material. For example, the addition of gellan gum allows effective reuse over at least eight clathration cycles without the need for reblending. DW and its "dry gel" modification may represent a potential platform for recyclable gas storage or gas separation on a practicable time scale in a static, unmixed system.

  2. Thermochemical cycles

    NASA Technical Reports Server (NTRS)

    Funk, J. E.; Soliman, M. A.; Carty, R. H.; Conger, W. L.; Cox, K. E.; Lawson, D.

    1975-01-01

    The thermochemical production of hydrogen is described along with the HYDRGN computer program which attempts to rate the various thermochemical cycles. Specific thermochemical cycles discussed include: iron sulfur cycle; iron chloride cycle; and hybrid sulfuric acid cycle.

  3. Self-protection in dry recycle technologies

    SciTech Connect

    Hannum, W.H.; Wade, D.; Stanford, G.

    1995-12-01

    In response to the INFCE conclusions, the U.S. undertook development of a new dry fuel cycle. Dry recycle processes have been demonstrated to be feasible. Safeguarding such fuel cycles will be dramatically simpler than the PUREX fuel cycle. At every step of the processes, the materials meet the {open_quotes}spent-fuel standard.{close_quotes} The scale is compatible with collocation of power reactors and their recycle facility, eliminating off-site transportation and storage of plutonium-bearing materials. Material diverted either covertly or overtly would be difficult (relative to material available by other means) to process into weapons feedstock.

  4. Investment opportunity : the FPL low-cost solar dry kiln

    Treesearch

    George B. Harpole

    1988-01-01

    Two equations are presented that may be used to estimate a maximum investment limit and working capital requirements for the FPL low-cost solar dry kiln systems. The equations require data for drying cycle time, green lumber cost, and kiln-dried lumber costs. Results are intended to provide a preliminary estimate.

  5. Dry Macular Degeneration

    MedlinePlus

    ... delay vision loss due to dry macular degeneration. Symptoms Dry macular degeneration symptoms usually develop gradually and without pain. They may ... of printed words Decreased intensity or brightness of ... causes total blindness. Dry macular degeneration is one of two types ...

  6. Drying temperature effects on fish dry mass measurements

    USGS Publications Warehouse

    Lantry, B.F.; O'Gorman, R.

    2007-01-01

    Analysis of tissue composition in fish often requires dry samples. Time needed to dry fish decreases as temperature is increased, but additional volatile material may be lost. Effects of 10??C temperature increases on percentage dry mass (%DM) were tested against 60??C controls for groups of lake trout Salvelinus namaycush, rainbow smelt Osmerus mordax, slimy sculpin Cottus cognatus, and alewife Alosa pseudoharengus. Lake trout %DMs were lower at greater temperatures, but not significantly different from 60??C controls. Rainbow smelt and slimy sculpin %DMs were lower at greater temperatures and differences were significant when test temperatures reached 90??C. Significant differences were not found in tests using alewives because variability in %DM was high between fish. To avoid inter-fish variability, 30 alewives were each dried successively at 60, 70, 80, and then 90??C and for all fish %DM declined at each higher temperature. In general, %DMs were lower at greater temperatures and after reaching a stable dry weight, fish did not lose additional mass if temperature remained constant. Results indicate that caution should be used when comparing dry mass related indices from fish dried at different temperatures because %DM was negatively related to temperature. The differences in %DM observed with rising temperature could account for substantial portions of the variability in reported energy values for the species tested. Differences in %DM means for the 60 vs. 80??C and 60 vs. 90??C tests for rainbow smelt and alewife could represent of from 8 to 38% of observed annual energy cycles for Lakes Ontario and Michigan.

  7. BIOMASS DRYING TECHNOLOGIES

    EPA Science Inventory

    The report examines the technologies used for drying of biomass and the energy requirements of biomass dryers. Biomass drying processes, drying methods, and the conventional types of dryers are surveyed generally. Drying methods and dryer studies using superheated steam as the d...

  8. BIOMASS DRYING TECHNOLOGIES

    EPA Science Inventory

    The report examines the technologies used for drying of biomass and the energy requirements of biomass dryers. Biomass drying processes, drying methods, and the conventional types of dryers are surveyed generally. Drying methods and dryer studies using superheated steam as the d...

  9. Experimental study on drying kinetic of cassava starch in a pneumatic drying system

    NASA Astrophysics Data System (ADS)

    Suherman, Kumoro, Andri Cahyo; Kusworo, Tutuk Djoko

    2015-12-01

    The aims of this study are to present the experimental research on the drying of cassava starch in a pneumatic dryer, to describe its drying curves, as well as to calculate its thermal efficiency. The effects of operating conditions, namely the inlet air temperature (60-100 °C) and solid-gas flow rate ratio (Ms/Mg 0.1-0.3) were studied. Heat transfer is accomplished through convection mechanism in a drying chamber based on the principle of direct contact between the heated air and the moist material. During the drying process, intensive heat and mass transfer between the drying air and the cassava starch take place. In order to meet the SNI standards on solid water content, the drying process was done in two cycles. The higher the temperature of the drying air, the lower the water content of the solids exiting the dryer. Thermal efficiency of the 2nd cycle was found to be lower than the 1st cycle.

  10. Dry eye syndrome

    MedlinePlus

    ... of dry eyes include: Dry environment or workplace (wind, air conditioning) Sun exposure Smoking or second-hand ... NOT smoke and avoid second-hand smoke, direct wind, and air conditioning. Use a humidifier, especially in ...

  11. Air drying of lumber.

    Treesearch

    1999-01-01

    This report describes how lumber can be air-dried most effectively under outdoor conditions and illustrates the principles and procedures of air-drying lumber that were developed through field investigations and observations of industrial practices. Particular emphasis is placed on the yarding of lumber in unit packages. Included are topics such as why lumber is dried...

  12. Energy-efficient regenerative liquid desiccant drying process

    DOEpatents

    Ko, Suk M.; Grodzka, Philomena G.; McCormick, Paul O.

    1980-01-01

    This invention relates to the use of desiccants in conjunction with an open oop drying cycle and a closed loop drying cycle to reclaim the energy expended in vaporizing moisture in harvested crops. In the closed loop cycle, the drying air is brought into contact with a desiccant after it exits the crop drying bin. Water vapor in the moist air is absorbed by the desiccant, thus reducing the relative humidity of the air. The air is then heated by the used desiccant and returned to the crop bin. During the open loop drying cycle the used desiccant is heated (either fossil or solar energy heat sources may be used) and regenerated at high temperature, driving water vapor from the desiccant. This water vapor is condensed and used to preheat the dilute (wet) desiccant before heat is added from the external source (fossil or solar). The latent heat of vaporization of the moisture removed from the desiccant is reclaimed in this manner. The sensible heat of the regenerated desiccant is utilized in the open loop drying cycle. Also, closed cycle operation implies that no net energy is expended in heating drying air.

  13. Structure of drying costs

    SciTech Connect

    Sztabert, Z.T.

    1996-05-01

    A knowledge of cost structure and cost behavior is necessary in the management activities, particularly in the domain of investment or production decision making, as well as in the areas of production cost planning and control. Prediction and analysis of values of cost components for different technologies of drying are important when selection of a drying method and drying equipment should be done. Cost structures of lumber and coal drying processes together with an application of the factor method for prediction of the drying cost are presented.

  14. Dry deposition velocities

    SciTech Connect

    Sehmel, G.A.

    1984-03-01

    Dry deposition velocities are very difficult to predict accurately. In this article, reported values of dry deposition velocities are summarized. This summary includes values from the literature on field measurements of gas and particle dry deposition velocities, and the uncertainties inherent in extrapolating field results to predict dry deposition velocities are discussed. A new method is described for predicting dry deposition velocity using a least-squares correlation of surface mass transfer resistances evaluated in wind tunnel experiments. 14 references, 4 figures, 1 table.

  15. The carbon dioxide cycle

    USGS Publications Warehouse

    James, P.B.; Hansen, G.B.; Titus, T.N.

    2005-01-01

    The seasonal CO2 cycle on Mars refers to the exchange of carbon dioxide between dry ice in the seasonal polar caps and gaseous carbon dioxide in the atmosphere. This review focuses on breakthroughs in understanding the process involving seasonal carbon dioxide phase changes that have occurred as a result of observations by Mars Global Surveyor. ?? 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  16. Drying low rank coal and retarding spontaneous ignition

    SciTech Connect

    Bellow, E.J. Jr.; Bixel, J.C.; Heaney, W.F.; Yan, T.Y.

    1989-05-09

    A method is described of passivating and cooling heated dried coal comprising: (a) heating particulate coal to a temperature between about 190 and about 230/sup 0/F to dry to the desired level: and (b) coating the resulting heated particulate coal with an aqueous emulsion of a hydrocarbon selected from the group consisting of petroleum resid, light cycle oil, heavy cycle oil, clarified slurry oil, durene, asphaltenes, coal tar and coal tar pitch.

  17. Design of drying chamber and biomass furnace for sun-biomass hybrid rice-drying machine

    NASA Astrophysics Data System (ADS)

    Satria, Dhimas; Haryadi, Austin, Ruben; Kurniawan, Bobby

    2016-03-01

    In most Asian countries, rice drying is carried out manually by exposing rice to sunlight. However, problem occurs when rain season comes. Lack of sunlight deters the drying process. This paper proposes a design of mechanical rice drying machine with hybrid sun-biomass energy source. Pahl & Beitz method, which consists of four steps process: function planning and clarification, design concept, design prototype, and design details; are used as design methodology. Based on design result and calculation, in this paper propose specifications for drying machine and biomass furnace. Drying chamber is a continuous flow system with pneumatic-conveyor as blower. This hybrid utilizes two types of energy sources, sun and biomass. The proposed machine has capacity of 500 kilograms per cycle using 455 Watt of energy, which is more efficient than ordinary heater. Biomass furnace utilizes heat transfer by means of arranging 64 pieces of stainless steel pipes of 0.65 diameters in parallel.

  18. Ambient Dried Aerogels

    NASA Technical Reports Server (NTRS)

    Jones, Steven M.; Paik, Jong-Ah

    2013-01-01

    A method has been developed for creating aerogel using normal pressure and ambient temperatures. All spacecraft, satellites, and landers require the use of thermal insulation due to the extreme environments encountered in space and on extraterrestrial bodies. Ambient dried aerogels introduce the possibility of using aerogel as thermal insulation in a wide variety of instances where supercritically dried aerogels cannot be used. More specifically, thermoelectric devices can use ambient dried aerogel, where the advantages are in situ production using the cast-in ability of an aerogel. Previously, aerogels required supercritical conditions (high temperature and high pressure) to be dried. Ambient dried aerogels can be dried at room temperature and pressure. This allows many materials, such as plastics and certain metal alloys that cannot survive supercritical conditions, to be directly immersed in liquid aerogel precursor and then encapsulated in the final, dried aerogel. Additionally, the metalized Mylar films that could not survive the previous methods of making aerogels can survive the ambient drying technique, thus making multilayer insulation (MLI) materials possible. This results in lighter insulation material as well. Because this innovation does not require high-temperature or high-pressure drying, ambient dried aerogels are much less expensive to produce. The equipment needed to conduct supercritical drying costs many tens of thousands of dollars, and has associated running expenses for power, pressurized gasses, and maintenance. The ambient drying process also expands the size of the pieces of aerogel that can be made because a high-temperature, high-pressure system typically has internal dimensions of up to 30 cm in diameter and 60 cm in height. In the case of this innovation, the only limitation on the size of the aerogels produced would be in the ability of the solvent in the wet gel to escape from the gel network.

  19. Dry pressing technical ceramics

    SciTech Connect

    Lewis, W.A. Jr.

    1996-04-01

    Dry pressing of technical ceramics is a fundamental method of producing high-quality ceramic components. The goals of dry pressing technical ceramics are uniform compact size and green density, consistent part-to-part green density and defect-free compact. Dry pressing is the axial compaction of loosely granulated dry ceramic powders (< 3% free moisture) within a die/punch arrangement. The powder, under pressure, conforms to the specific shape of the punch faces and die. Powder compaction occurs within a rigid-walled die and usually between a top and bottom punch. Press configurations include anvil, rotary, multiple-punch and multiple-action.

  20. Menstrual Cycle

    MedlinePlus

    ... receive Pregnancy email updates Enter email Submit The menstrual cycle Day 1 starts with the first day of ... drop around Day 25 . This signals the next menstrual cycle to begin. The egg will break apart and ...

  1. Influence of Cutting Cycle and Spacing on Coppice Sycamore Yield

    Treesearch

    H. E. Kennedy

    1975-01-01

    Cutting cycle significantly affected total aboveground dry-weight yields, which were greater with the 2-, 3-, and 4-year cycles than with the I-year. For all cutting cycles, significantly higher yields were obtained with 2- by 5-foot spacings than with 4 by 5. Dry-weight yields ranged from 3,229 pounds per acre per year for the I-year cutting cycle spaced at 4 by 5...

  2. Tray Drying of Solids.

    ERIC Educational Resources Information Center

    Afacan, Artin; Masliyah, Jacob

    1984-01-01

    Describes a drying experiment useful in presenting the concept of simultaneous heat and mass transfer. Background information, equipment requirements, experimental procedures, and results are provided. The reasonably good agreement in the calculated rate of drying and that observed experimentally makes students feel confident in applying…

  3. Tray Drying of Solids.

    ERIC Educational Resources Information Center

    Afacan, Artin; Masliyah, Jacob

    1984-01-01

    Describes a drying experiment useful in presenting the concept of simultaneous heat and mass transfer. Background information, equipment requirements, experimental procedures, and results are provided. The reasonably good agreement in the calculated rate of drying and that observed experimentally makes students feel confident in applying…

  4. Indiana Corn Dry Mill

    SciTech Connect

    2006-09-01

    The goal of this project is to perform engineering, project design, and permitting for the creation and commercial demonstration of a corn dry mill biorefinery that will produce fuel-grade ethanol, distillers dry grain for animal feed, and carbon dioxide for industrial use.

  5. Dry imaging cameras.

    PubMed

    Indrajit, Ik; Alam, Aftab; Sahni, Hirdesh; Bhatia, Mukul; Sahu, Samaresh

    2011-04-01

    Dry imaging cameras are important hard copy devices in radiology. Using dry imaging camera, multiformat images of digital modalities in radiology are created from a sealed unit of unexposed films. The functioning of a modern dry camera, involves a blend of concurrent processes, in areas of diverse sciences like computers, mechanics, thermal, optics, electricity and radiography. Broadly, hard copy devices are classified as laser and non laser based technology. When compared with the working knowledge and technical awareness of different modalities in radiology, the understanding of a dry imaging camera is often superficial and neglected. To fill this void, this article outlines the key features of a modern dry camera and its important issues that impact radiology workflow.

  6. Infrared drying of strawberry.

    PubMed

    Adak, Nafiye; Heybeli, Nursel; Ertekin, Can

    2017-03-15

    The effects of different drying conditions, such as infrared power, drying air temperature and velocity, on quality of strawberry were evaluated. Drying time decreased with increased infrared power, air temperature and velocity. An increase in power from 100W to 300W, temperature from 60 to 80°C and velocity from 1.0m.s(-1) to 2.0m.s(-1) decreased fruit color quality index. For total phenol and anthocyanin content, 300W, 60°C, and 1.0m.s(-1) were superior to the other experimental conditions. The drying processes increased N, P and K and decreased Ca, Mg, Fe, Mn, Zn and Cu contents. The optimal conditions to preserve nutrients in infrared drying of strawberry were 200W, 100°C and 1.5m.s(-1). Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Packaged kiln dried firewood

    SciTech Connect

    Cutrara, A.

    1986-07-01

    A process is described for kiln drying firewood consisting of essentially uniform lengths of split firewood pieces, the process comprising splitting essentially uniform lengths of green tree logs to form firewood pieces, placing the firewood pieces in open mesh bags to provide a plurality of bags of firewood, placing the plurality of bags of green firewood pieces in a kiln drying oven, kiln drying the pieces at temperatures in excess of 150/sup 0/F. by moving heated air over the pieces until the pieces have an overall moisture content ranging from 15% up to 30% by weight, operating the kiln at a temperature below a level which would render the structural characteristics of the bag useless and removing the kiln dried firewood pieces in the plurality of bags from the kiln drying oven.

  8. Dry imaging cameras

    PubMed Central

    Indrajit, IK; Alam, Aftab; Sahni, Hirdesh; Bhatia, Mukul; Sahu, Samaresh

    2011-01-01

    Dry imaging cameras are important hard copy devices in radiology. Using dry imaging camera, multiformat images of digital modalities in radiology are created from a sealed unit of unexposed films. The functioning of a modern dry camera, involves a blend of concurrent processes, in areas of diverse sciences like computers, mechanics, thermal, optics, electricity and radiography. Broadly, hard copy devices are classified as laser and non laser based technology. When compared with the working knowledge and technical awareness of different modalities in radiology, the understanding of a dry imaging camera is often superficial and neglected. To fill this void, this article outlines the key features of a modern dry camera and its important issues that impact radiology workflow. PMID:21799589

  9. Annotated Bibliography for Drying Nuclear Fuel

    SciTech Connect

    Rebecca E. Smith

    2011-09-01

    Internationally, the nuclear industry is represented by both commercial utilities and research institutions. Over the past two decades many of these entities have had to relocate inventories of spent nuclear fuel from underwater storage to dry storage. These efforts were primarily prompted by two factors: insufficient storage capacity (potentially precipitated by an open-ended nuclear fuel cycle) or deteriorating quality of existing underwater facilities. The intent of developing this bibliography is to assess what issues associated with fuel drying have been identified, to consider where concerns have been satisfactorily addressed, and to recommend where additional research would offer the most value to the commercial industry and the U. S. Department of Energy.

  10. Freeze drying method

    DOEpatents

    Coppa, Nicholas V.; Stewart, Paul; Renzi, Ernesto

    1999-01-01

    The present invention provides methods and apparatus for freeze drying in which a solution, which can be a radioactive salt dissolved within an acid, is frozen into a solid on vertical plates provided within a freeze drying chamber. The solid is sublimated into vapor and condensed in a cold condenser positioned above the freeze drying chamber and connected thereto by a conduit. The vertical positioning of the cold condenser relative to the freeze dryer helps to help prevent substances such as radioactive materials separated from the solution from contaminating the cold condenser. Additionally, the system can be charged with an inert gas to produce a down rush of gas into the freeze drying chamber to also help prevent such substances from contaminating the cold condenser.

  11. Freeze drying apparatus

    DOEpatents

    Coppa, Nicholas V.; Stewart, Paul; Renzi, Ernesto

    2001-01-01

    The present invention provides methods and apparatus for freeze drying in which a solution, which can be a radioactive salt dissolved within an acid, is frozen into a solid on vertical plates provided within a freeze drying chamber. The solid is sublimated into vapor and condensed in a cold condenser positioned above the freeze drying chamber and connected thereto by a conduit. The vertical positioning of the cold condenser relative to the freeze dryer helps to help prevent substances such as radioactive materials separated from the solution from contaminating the cold condenser. Additionally, the system can be charged with an inert gas to produce a down rush of gas into the freeze drying chamber to also help prevent such substances from contaminating the cold condenser.

  12. Dry Mouth - Multiple Languages

    MedlinePlus

    ... Hmoob) Japanese (日本語) Korean (한국어) Nepali (नेपाली) Russian (Русский) Somali (Af-Soomaali ) Spanish (español) Ukrainian (українська ) ... नेपाली (Nepali) Bilingual PDF Health Information Translations Russian (Русский) Expand Section Dry Mouth - English Dry Mouth - ...

  13. Dry kiln operator's manual

    Treesearch

    William T. Simpson

    1991-01-01

    The modern dry kiln is a unique product of research, development, and experience. It is the only practical means now in wide use for rapid, high- volume drying of lumber to conditions necessary for maximum serviceability in housing, furniture, millwork, and many other wood products. As part of our charge to help further the efficient utilization of our nation’s timber...

  14. Acoustoconvection Drying of Meat

    NASA Astrophysics Data System (ADS)

    Zhilin, A. A.; Fedorov, A. V.

    2016-03-01

    The dynamics of moisture extraction from meat samples by the acoustoconvection and thermoconvection methods has been investigated. To describe the dynamics of moisture extraction from meat, we propose a simple relaxation model with a relaxation time of 8-10 min in satisfactorily describing experimental data on acoustoconvection drying of meat. For thermoconvection drying the relaxation time is thereby 30 and 45 min for the longitudinal and transverse positions of fibers, respectively.

  15. Investment opportunity: the FPL (Forest Products Laboratory) low-cost solar-dry kiln

    SciTech Connect

    Harpole, G.B.

    1988-09-01

    Two equations are presented that may be used to estimate a maximum investment limit and working capital requirements for the FPL low-cost solar-dry kiln systems. The equations require data for drying-cycle time, green-lumber cost, and kiln-dried lumber costs. Results are intended to provide a preliminary estimate.

  16. Drying SDS-Polyacrylamide Gels.

    PubMed

    Sambrook, Joseph; Russell, David W

    2006-09-01

    INTRODUCTIONThis protocol describes a method for drying SDS-polyacrylamide gels. Gels containing proteins radiolabeled with (35)S-labeled amino acids must be dried before autoradiographic images can be obtained. Nonradioactive gels can also be preserved by drying.

  17. Tracking Amazonian cheese microbial diversity: Development of an original, sustainable, and robust starter by freeze drying/spray drying.

    PubMed

    Ferreira, A A; Huang, S; Perrone, Í T; Schuck, P; Jan, G; Carvalho, A F

    2017-09-01

    Marajó cheese made with raw buffalo milk in the Amazon region of Brazil can be considered a good source of wild lactic acid bacteria strains with unexplored and promising characteristics. The aim of this study was to develop a potential probiotic starter culture for industrial applications using freeze drying and spray drying. A decrease in the survival rates of freeze-dried samples compared with spray-dried samples was noted. The spray-dried cultures remained approximately 10(9) cfu·g(-1), whereas the freeze-dried samples showed 10(7) cfu·g(-1) after 60 d of storage at 4°C. All of the spray-dried samples showed a greater ability to decrease the pH in 10% skim milk over 24 h compared with the freeze-dried samples. The spray-dried samples showed a greater resistance to acidic conditions and to the presence of bile salts. In addition, under heat stress conditions, reduction was under 2 log cycles in all samples. Although the survival rate was similar among the evaluated samples after drying, the technological performance for skim milk showed some differences. This study may direct further investigations into how to preserve lactic acid bacteria probiotics to produce spray-dried starters that have a high number of viable cells that can then be used for industrial applications in a cost-effective way. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  18. Solar fish drying in the Republic of Guinea

    SciTech Connect

    Cosby, R.M.; Govaer, D. ); Diallo, A.

    1990-09-01

    The use of a natural-flow solar dryer for drying fish in the Republic of Guinea was investigated. The construction of a simple, family-size, prototype solar dryer required only basic fabrication skills and materials readily available in Guinea. Drying experiments on whiting and catfish under simulated sunlight demonstrated an initial drying phase with a constant water-removal rate followed by a decreasing rate until drying ceased. Overall drying rates indicated that a residential-scale dryer could operate on a two-day cycle and provide a quality dried product. The utilization of the ubiquitous solar energy resource in a stand-alone, locally constructed, small-scale unit for the purpose of food preservation can have positive economic, environmental, and social impacts in Guinea. 2 refs., 3 figs.

  19. Freeze-drying today and tomorrow.

    PubMed

    Leary, J H; Stanford, E A

    1976-10-01

    The freeze-drying process and equipment have been improved over the years; the cycle times have shortened and the dried products have improved as a result. This talk will deal with these improvements and how we have progressed from the early systems to where we are today. Such areas of discussion will include: vacuum pumping systems, how they are sized and designed to meet the needs for general and special applications; heat transfer systems, and their use in maintaining the drying profile; condensing surface design, and what is best for certain types of dryers; controls and instrumentation, and how these have played a big part in the drying process and have made it possible to get repeatability; refrigeration systems, and the part they play in the performance of freeze-drying; and lastly the effect of internal stoppering, bottomless trays, and other items such as these have had on the present state of the art. It goes without saying that there have been many changes and there will continue to be changes and we shall endeavor to look into the future--as to what might well bo some of these changes. Included in the talk will be a number of slides and illustrations to point out the various items as they are discussed.

  20. Cycle Analysis

    SciTech Connect

    Wright, Steven A.

    2012-03-20

    1. The Cycle Analysis code is an Microsoft Excel code that performs many different types of thermodynamic cycle analysis for power producing systems. The code will calculate the temperature and pressure and all other thermodynamic properties at the inlet and outlet of each component. The code also calculates the power that is produced, the efficiency, and the heat transported in the heater, gas chiller and recuperators. The code provides a schematic of the loop and provides the temperature and pressure at each location in the loop. The code also provides a T-S (temperature-entropy) diagram of the loop and often it provides an pressure enthalpy plot as well. 2. This version of the code concentrates on supercritical CO2 power cycles, but by simply changing the name of the working fluid many other types of fluids can be analyzed. The Cycle Analysis code provided here contains 18 different types of power cycles. Each cycle is contained in one worksheet or tab that the user can select. The user can change the yellow highlighted regions to perform different thermodynamic cycle analysis.

  1. Trigger Point Dry Needling.

    PubMed

    2017-03-01

    Increasingly, physical therapists in the United States and throughout the world are using dry needling to treat musculoskeletal pain, even though this treatment has been a controversial addition to practice. To better generalize to physical therapy practice the findings about dry needling thus far, the authors of a study published in the March 2017 issue of JOSPT identified the need for a systematic review examining the effectiveness of dry needling performed by physical therapists on people with musculoskeletal pain. Their review offers a meta-analysis of data from several included studies and assesses the evidence for risks of bias. J Orthop Sports Phys Ther 2017;47(3):150. doi:10.2519/jospt.2017.0502.

  2. Magnetically responsive dry fluids

    NASA Astrophysics Data System (ADS)

    Sousa, Filipa L.; Bustamante, Rodney; Millán, Angel; Palacio, Fernando; Trindade, Tito; Silva, Nuno J. O.

    2013-07-01

    Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid.Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01784b

  3. Microbial growth responses upon rewetting dry soil

    NASA Astrophysics Data System (ADS)

    Meisner, Annelein; Rousk, Johannes; Bååth, Erland

    2015-04-01

    Increased rainfall and drought periods are expected to occur with current climate change, leading to fluctuations in soil moisture. Changes in soil moisture are known to affect carbon cycling. A pulse of carbon dioxide release (respiration) is often observed after rewetting a dry soil and a drying threshold is observed before this pulse emerges. Increased microbial activity is often assumed to be the cause for the pulse in respiration. Yet, the microbial growth responses that underlie this pulse are often not studied. The following questions will be addressed in this presentation. 1) Do fungal and bacterial growth explain the pulse in respiration upon rewetting a dry soil? 2) How does microbial growth respond to different drying intensities before rewetting? To answer the research questions, soils from Sweden, U.K. and Greenland were put in microcosms, air-dried for four days, a prolonged period or to different moisture content before rewetting. We measured soil respiration, fungal growth rates and/or bacterial growth rates at high temporal resolution during one week after rewetting. Our results suggest that the respiration pulse upon rewetting dry soil is not due to high microbial growth rates. During the first hours after rewetting, bacterial and fungal growth rates were low whereas the respiration rates were high. As such, there was a decoupling between the pulse in respiration and microbial growth rates. Two patterns of bacterial growth were observed upon rewetting the three different soils. In "pattern 1", bacteria started growing immediately in a linear pattern up to values similar as the moist control. In "pattern 2", bacteria started growing exponentially after a lag period of no growth with a second pulse of respiration occurring at the start of bacterial growth. Manipulating the drying intensity changed the patterns. Soils with "pattern 1" were changed to "pattern 2" when subjected to more extensive drying periods whereas soils with "pattern 2" were

  4. Sterilization by dry heat

    PubMed Central

    Darmady, E. M.; Hughes, K. E. A.; Jones, J. D.; Prince, D.; Tuke, Winifred

    1961-01-01

    The advantages and disadvantages of three forms of dry heat sterilization are discussed. In addition a fourth method, consisting of heating by infrared rays in vacuo, is described. This method is particularly suitable for instruments used in the operating theatre, since it can replace an autoclave where a supply of steam is not available. Recommended times and temperatures for dry heat sterilization are detailed, and are related to the thermal death point of Cl. tetani. The dangers of recontamination during the cooling process are discussed. PMID:13719782

  5. Menstrual Cycle

    MedlinePlus

    ... to the Professional version Home Women's Health Issues Biology of the Female Reproductive System Menstrual Cycle Follicular ... Version. DOCTORS: Click here for the Professional Version Biology of the Female Reproductive System Overview of the ...

  6. Cycling injuries.

    PubMed Central

    Cohen, G. C.

    1993-01-01

    Bicycle-related injuries have increased as cycling has become more popular. Most injuries to recreational riders are associated with overuse or improper fit of the bicycle. Injuries to racers often result from high speeds, which predispose riders to muscle strains, collisions, and falls. Cyclists contact bicycles at the pedals, seat, and handlebars. Each is associated with particular cycling injuries. Images Figure 1 Figure 3 Figure 4 Figure 5 PMID:8471908

  7. Drying drops of blood

    NASA Astrophysics Data System (ADS)

    Brutin, David; Sobac, Benjamin; Loquet, Boris; Sampol, José.

    2010-11-01

    The drying of a drop of human blood is fascinating by the complexity of the physical mechanisms that occur as well as the beauty of the phenomenon which has never been previously evidenced in the literature. The final stage of full blood evaporation reveals for a healthy person the same regular pattern with a good reproducibility. Other tests on anemia and hyperlipidemic persons were performed and presented different patterns. By means of digital camera, the influence of the motion of red blood cells (RBCs) which represent about 50% of the blood volume, is revealed as well as its consequences on the final stages of drying. The mechanisms which lead to the final pattern of dried blood drops are presented and explained on the basis of fluid and solid mechanics in conjunction with the principles of hematology. Our group is the first to evidence that the specific regular patterns characteristic of a healthy individual do not appear in a dried drop of blood from a person with blood disease. Blood is a complex colloidal suspension for which the flow motion is clearly non-Newtonian. When drops of blood evaporate, all the colloids are carried by the flow motion inside the drop and interact.

  8. Dry Valleys, Antarctica

    NASA Image and Video Library

    2009-11-02

    The McMurdo Dry Valleys are a row of valleys west of McMurdo Sound, Antarctica. They are so named because of their extremely low humidity and lack of snow and ice cover. This image was acquired December 8, 2002 by NASA Terra spacecraft.

  9. Dry piston coal feeder

    DOEpatents

    Hathaway, Thomas J.; Bell, Jr., Harold S.

    1979-01-01

    This invention provides a solids feeder for feeding dry coal to a pressurized gasifier at elevated temperatures substantially without losing gas from the gasifier by providing a lock having a double-acting piston that feeds the coals into the gasifier, traps the gas from escaping, and expels the trapped gas back into the gasifier.

  10. Cooling of dried coal

    SciTech Connect

    Siddoway, M.A.

    1988-06-14

    This patent describes a process for noncombustibly drying particulate coal comprising: separating the coal into two wet coal streams; passing one wet coal system into a dryer to form a bed; heating air in a furnace; admitting the heated air to the dryer to fluidize the bed; withdrawing dryer exhaust gas; passing the exhaust gas through a cyclone and withdrawing coal fines from the cyclone; withdrawing a hot, dry coal stream from the dryer; blending the drier hot dry coal stream with the cyclone coal fines; withdrawing cyclone exhaust gas; wet scrubbing the cyclone exhaust gas to form a coal fines slurry and scrubber exhaust gas; passing the coal fines slurry to a sedimentation pool; blending the second wet coal stream with the drier hot dry coal stream and the cyclone coal fines; passing the latter blended stream to a cooler to form a bed; fluidizing the latter bed with ambient air; withdrawing cooler exhaust gas and passing the gas to a cyclone; passing exhaust gas from the latter cyclone to a baghouse and collecting coal fines therein; passing the latter coal fines to the furnace as fuel for heating the air; and withdrawing cooled coal from the cooler and blending the cooled coal with coal fines from the latter cyclone.

  11. Dried Fruits and Nuts

    USDA-ARS?s Scientific Manuscript database

    Current control of postharvest insect pests of dried fruits and tree nuts relies heavily on fumigants such as methyl bromide or phosphine. There is mounting pressure against the general use of chemical fumigants due to atmospheric emissions, safety or health concerns, and an increased interest in or...

  12. Improved formulation and lyophilization cycle for rBCG vaccine.

    PubMed

    Jin, Tom H; Nguyen, Lisa; Qu, Tianli; Tsao, Eric

    2011-06-24

    To improve the conventional BCG vaccine in cake appearance and integrity, a new formulation with corresponding freeze drying cycle was developed for a recombinant BCG vaccine. The new formulation contains mannitol as a bulking agent, and trehalose, sucrose and sodium glutamate as stabilizers. The formulation and freeze drying cycle were tested with different super cooling rates and secondary drying temperatures, with or without an annealing process. Thermodynamic behavior was characterized using differential scanning calorimetry (DSC). Varying the secondary drying temperature and presence/absence of an annealing step caused marked differences in cake thermodynamic profiles irrespective of different cooling rates. The annealing process allowed efficient crystallization of the mannitol. Failure to crystallize the bulking agent had the potential to depress the Tg' and compromise storage stability in the final lyophile by crystallizing from the solid during storage, even when the secondary drying temperature was as high as 40°C. The improved formulation and freeze drying cycle resulted in good recovery of 53.2% during lyophilization and a higher survival rate of 61.7% in an accelerated stability study than the conventional BCG formulation and cycle. In summary, full crystallization was necessary for the mannitol bulking formulation. The freeze dried rBCG vials obtained using the formulation and drying cycle developed here met the requirements of BCG vaccine in good cake appearance, high viability post freeze drying and heat stability during storage. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Quality of dry ginger (Zingiber officinale) by different drying methods.

    PubMed

    E, Jayashree; R, Visvanathan; T, John Zachariah

    2014-11-01

    Ginger rhizomes sliced to various lengths of 5, 10, 15, 20, 30, 40, 50 mm and whole rhizomes were dried from an initial moisture content of 81.3 % to final moisture content of less than 10 % by various drying methods like sun drying, solar tunnel drying and cabinet tray drying at temperatures of 50, 55, 60 and 65 °C. Slicing of ginger rhizomes significantly reduced the drying time of ginger in all the drying methods. It was observed that drying of whole ginger rhizomes under sun took the maximum time (9 days) followed by solar tunnel drying (8 days). Significant reduction in essential oil and oleoresin content of dry ginger was found as the slice length decreased. The important constituents of ginger essential oil like zingiberene, limonene, linalool, geraniol and nerolidol as determined using a gas chromatography was also found to decrease during slicing and as the drying temperature increased. The pungency constituents in the oleoresin of ginger like total gingerols and total shogoals as determined using a reverse phase high performance liquid chromatography also showed a decreasing trend on slicing and with the increase in drying temperature. It was observed from the drying studies that whole ginger rhizomes dried under sun drying or in a solar tunnel drier retained the maximum essential oil (13.9 mg/g) and oleoresin content (45.2 mg/g) of dry ginger. In mechanical drying, the drying temperature of 60 °C was considered optimum however there was about 12.2 % loss in essential oil at this temperature.

  14. Vapor Compression Cycle Design Program (CYCLE_D)

    National Institute of Standards and Technology Data Gateway

    SRD 49 NIST Vapor Compression Cycle Design Program (CYCLE_D) (PC database for purchase)   The CYCLE_D database package simulates the vapor compression refrigeration cycles. It is fully compatible with REFPROP 9.0 and covers the 62 single-compound refrigerants . Fluids can be used in mixtures comprising up to five components.

  15. Use of manometric temperature measurements (MTM) to characterize the freeze-drying behavior of amorphous protein formulations.

    PubMed

    Johnson, Robert E; Oldroyd, Megan E; Ahmed, Saleem S; Gieseler, Henning; Lewis, Lavinia M

    2010-06-01

    The freeze-drying behavior and cake morphology of a model protein in an amorphous formulation were studied at varying protein concentrations using conservative (-25 degrees C) and aggressive (+25 degrees C) shelf temperatures at constant chamber pressure during primary drying. The two cycles were characterized by manometric temperature measurements (MTM) in a SMART freeze dryer that estimates the sublimation rate (dm/dt), product temperature at the freeze-drying front (T(p-MTM)) and product resistance (R(p)) during a run. The calculated sublimation rates (dm/dt) were 3-4 times faster in the aggressive cycle compared to the conservative cycle. For conservatively dried cakes R(p) increased with both dry layer thickness and protein concentration. For aggressively dried cakes (where freeze-drying occurs at the edge of microcollapse), R(p) also increased with protein concentration but was independent of the dry layer thickness. The sublimation rate was influenced by R(p), dry layer thickness and T(p-MTM) in the conservative cycle, but was governed mainly by T(p-MTM) in the aggressive cycle, where R(p) is independent of the dry layer thickness. The aggressively dried cakes had a more open and porous structure compared to their conservatively dried counterparts. (c) 2009 Wiley-Liss, Inc. and the American Pharmacists Association

  16. Pore scale processes in dry soils

    NASA Astrophysics Data System (ADS)

    Schimel, J.

    2015-12-01

    Almost all soils experience regular drought and rewetting events. Yet most of our understanding of soil processes focuses on the moist periods, when plants are growing and nutrients are actively cycling. Yet, as soils dry, processes continue, yet change. Microbes shift their metabolic pathways from growth to survival, producing extracellular polymeric substances (EPS), sporulating, and going dormant. Under dry conditions, biotic processes are constrained but abiotic, chemical processes continue potentially altering soil aggregation and structure; in clayey California annual grassland & woodland soils pools of bioavailable water extractable organic carbon (WEOC) increase as does microbial biomass. Finally at rewetting, the pulse of water mobilizes resources, stimulates microbial activity and produces a flush of respiration and nutrient mineralization that can mobilize resources that had been previously inaccessible. One question that has driven much research has been where the organic matter comes from that drives these processes. We had hypothesized that the source of C for the dry-season increases was from the previous winter's dead roots, but field experiments where we maintained plots plant-free for two years showed no decline in the production of WEOC, nor in the early-season respiration pulses following rewetting. In this presentation, we will discuss recent work integrating measurements on aggregation (driven both by biotic and abiotic processes), EPS production, and the dynamics of WEOC and microbial biomass and how they function differently under dry and moist conditions.

  17. Biogeochemical stoichiometry of Antarctic Dry Valley ecosystems

    NASA Astrophysics Data System (ADS)

    Barrett, J. E.; Virginia, R. A.; Lyons, W. B.; McKnight, D. M.; Priscu, J. C.; Doran, P. T.; Fountain, A. G.; Wall, D. H.; Moorhead, D. L.

    2007-03-01

    Among aquatic and terrestrial landscapes of the McMurdo Dry Valleys, Antarctica, ecosystem stoichiometry ranges from values near the Redfield ratios for C:N:P to nutrient concentrations in proportions far above or below ratios necessary to support balanced microbial growth. This polar desert provides an opportunity to evaluate stoichiometric approaches to understand nutrient cycling in an ecosystem where biological diversity and activity are low, and controls over the movement and mass balances of nutrients operate over 10-106 years. The simple organisms (microbial and metazoan) comprising dry valley foodwebs adhere to strict biochemical requirements in the composition of their biomass, and when activated by availability of liquid water, they influence the chemical composition of their environment according to these ratios. Nitrogen and phosphorus varied significantly in terrestrial and aquatic ecosystems occurring on landscape surfaces across a wide range of exposure ages, indicating strong influences of landscape development and geochemistry on nutrient availability. Biota control the elemental ratio of stream waters, while geochemical stoichiometry (e.g., weathering, atmospheric deposition) evidently limits the distribution of soil invertebrates. We present a conceptual model describing transformations across dry valley landscapes facilitated by exchanges of liquid water and biotic processing of dissolved nutrients. We conclude that contemporary ecosystem stoichiometry of Antarctic Dry Valley soils, glaciers, streams, and lakes results from a combination of extant biological processes superimposed on a legacy of landscape processes and previous climates.

  18. Dry etching of metallization

    NASA Technical Reports Server (NTRS)

    Bollinger, D.

    1983-01-01

    The production dry etch processes are reviewed from the perspective of microelectronic fabrication applications. The major dry etch processes used in the fabrication of microelectronic devices can be divided into two categories - plasma processes in which samples are directly exposed to an electrical discharge, and ion beam processes in which samples are etched by a beam of ions extracted from a discharge. The plasma etch processes can be distinguished by the degree to which ion bombardment contributes to the etch process. This, in turn is related to capability for anisotropic etching. Reactive Ion Etching (RIE) and Ion Beam Etching are of most interest for etching of thin film metals. RIE is generally considered the best process for large volume, anisotropic aluminum etching.

  19. The questionably dry eye.

    PubMed Central

    Mackie, I. A.; Seal, D. V.

    1981-01-01

    This paper is concerned with the recognition of the dry eye when the clinical diagnosis is in doubt and other external eye diseases may be present. Papillary conjunctivitis is common to the dry eye as well as other pathological conditions and confuses the diagnosis. We have correlated the factors involved in the assessment for dryness. We have shown that particulate matter in the unstained tear film is associated with low tear lysozyme concentration. Tear flow and tear lysozyme are not necessarily interrelated, but a low lysozyme concentration (tear lysozyme ratio < 1.0) is associated with keratoconjunctivitis sicca. The Schirmer I test can produce false positive results, and we have suggested a modification to overcome this. This modified test will detect the eye with severely depleted lysozyme secretion, but it is unreliable for detecting the eye with moderately depleted secretion. We find that its lowest normal limit should be considered as 6 mm. Images PMID:7448154

  20. Drying of DNA droplets.

    PubMed

    Fang, Xiaohua; Li, Bingquan; Petersen, Eric; Seo, Young-Soo; Samuilov, Vladimir A; Chen, Yong; Sokolov, Jonathan C; Shew, Chwen-Yang; Rafailovich, Miriam H

    2006-07-04

    The evaporation kinetics of droplets containing DNA was studied, as a function of DNA concentration. Drops containing very low DNA concentrations dried by maintaining a constant base, whereas those with high concentration dried with a constant contact angle. To understand this phenomenon, the distribution of the DNA inside the droplet was measured using confocal microscopy. The results indicated that the DNA was condensed mostly on the surface of the droplets. In the case of high concentration droplets, it formed a shell, whereas isolated islands were found for droplets of low DNA concentrations. Rheologic results indicate the formation of a hydro gel in the low concentration drops, whereas phase separation between the self-assembled DNA structures and the water phase occurred at higher concentration.

  1. Virtual DRI dataset development

    NASA Astrophysics Data System (ADS)

    Hixson, Jonathan G.; Teaney, Brian P.; May, Christopher; Maurer, Tana; Nelson, Michael B.; Pham, Justin R.

    2017-05-01

    The U.S. Army RDECOM CERDEC NVESD MSD's target acquisition models have been used for many years by the military analysis community for sensor design, trade studies, and field performance prediction. This paper analyzes the results of perception tests performed to compare the results of a field DRI (Detection, Recognition, and Identification Test) performed in 2009 to current Soldier performance viewing the same imagery in a laboratory environment and simulated imagery of the same data set. The purpose of the experiment is to build a robust data set for use in the virtual prototyping of infrared sensors. This data set will provide a strong foundation relating, model predictions, field DRI results and simulated imagery.

  2. Ultrasonic Clothes Drying Technology

    ScienceCinema

    Patel, Viral; Momen, Ayyoub

    2016-07-12

    Oak Ridge National Laboratory researchers Ayyoub Momen and Viral Patel demonstrate a direct contact ultrasonic clothes dryer under development by ORNL in collaboration with General Electric (GE) Appliances. This novel approach uses high-frequency mechanical vibrations instead of heat to extract moisture as cold mist, dramatically reducing drying time and energy use. Funding for this project was competitively awarded by DOE’s Building Technologies Office in 2014.

  3. Ultrasonic Clothes Drying Technology

    SciTech Connect

    Patel, Viral; Momen, Ayyoub

    2016-05-09

    Oak Ridge National Laboratory researchers Ayyoub Momen and Viral Patel demonstrate a direct contact ultrasonic clothes dryer under development by ORNL in collaboration with General Electric (GE) Appliances. This novel approach uses high-frequency mechanical vibrations instead of heat to extract moisture as cold mist, dramatically reducing drying time and energy use. Funding for this project was competitively awarded by DOE’s Building Technologies Office in 2014.

  4. Superlubricity of dry nanocontacts

    NASA Astrophysics Data System (ADS)

    Gnecco, Enrico; Maier, Sabine; Meyer, Ernst

    2008-09-01

    We discuss how various forms of dry superlubricity, recently observed on the nanoscale, have been interpreted by simple phenomenological models. In particular, we review the cases of static and dynamic single-contact lubricity, thermolubricity, and structural lubricity. All these phenomena have been studied by friction force microscopy and explained using the classical Prandtl-Tomlinson model and its extensions, including thermal activation, temporal and spatial variations of the surface energy corrugation, and multiple-contact effects.

  5. Drying of fiber webs

    DOEpatents

    Warren, D.W.

    1997-04-15

    A process and an apparatus are disclosed for high-intensity drying of fiber webs or sheets, such as newsprint, printing and writing papers, packaging paper, and paperboard or linerboard, as they are formed on a paper machine. The invention uses direct contact between the wet fiber web or sheet and various molten heat transfer fluids, such as liquefied eutectic metal alloys, to impart heat at high rates over prolonged durations, in order to achieve ambient boiling of moisture contained within the web. The molten fluid contact process causes steam vapor to emanate from the web surface, without dilution by ambient air; and it is differentiated from the evaporative drying techniques of the prior industrial art, which depend on the uses of steam-heated cylinders to supply heat to the paper web surface, and ambient air to carry away moisture, which is evaporated from the web surface. Contact between the wet fiber web and the molten fluid can be accomplished either by submersing the web within a molten bath or by coating the surface of the web with the molten media. Because of the high interfacial surface tension between the molten media and the cellulose fiber comprising the paper web, the molten media does not appreciatively stick to the paper after it is dried. Steam generated from the paper web is collected and condensed without dilution by ambient air to allow heat recovery at significantly higher temperature levels than attainable in evaporative dryers. 6 figs.

  6. Drying of fiber webs

    DOEpatents

    Warren, David W.

    1997-01-01

    A process and an apparatus for high-intensity drying of fiber webs or sheets, such as newsprint, printing and writing papers, packaging paper, and paperboard or linerboard, as they are formed on a paper machine. The invention uses direct contact between the wet fiber web or sheet and various molten heat transfer fluids, such as liquified eutectic metal alloys, to impart heat at high rates over prolonged durations, in order to achieve ambient boiling of moisture contained within the web. The molten fluid contact process causes steam vapor to emanate from the web surface, without dilution by ambient air; and it is differentiated from the evaporative drying techniques of the prior industrial art, which depend on the uses of steam-heated cylinders to supply heat to the paper web surface, and ambient air to carry away moisture, which is evaporated from the web surface. Contact between the wet fiber web and the molten fluid can be accomplished either by submersing the web within a molten bath or by coating the surface of the web with the molten media. Because of the high interfacial surface tension between the molten media and the cellulose fiber comprising the paper web, the molten media does not appreciately stick to the paper after it is dried. Steam generated from the paper web is collected and condensed without dilution by ambient air to allow heat recovery at significantly higher temperature levels than attainable in evaporative dryers.

  7. Stabilization of Live Attenuated Influenza Vaccines by Freeze Drying, Spray Drying, and Foam Drying.

    PubMed

    Lovalenti, Phillip M; Anderl, Jeff; Yee, Luisa; Nguyen, Van; Ghavami, Behnaz; Ohtake, Satoshi; Saxena, Atul; Voss, Thomas; Truong-Le, Vu

    2016-05-01

    The goal of this research is to develop stable formulations for live attenuated influenza vaccines (LAIV) by employing the drying methods freeze drying, spray drying, and foam drying. Formulated live attenuated Type-A H1N1 and B-strain influenza vaccines with a variety of excipient combinations were dried using one of the three drying methods. Process and storage stability at 4, 25 and 37°C of the LAIV in these formulations was monitored using a TCID50 potency assay. Their immunogenicity was also evaluated in a ferret model. The thermal stability of H1N1 vaccine was significantly enhanced through application of unique formulation combinations and drying processes. Foam dried formulations were as much as an order of magnitude more stable than either spray dried or freeze dried formulations, while exhibiting low process loss and full retention of immunogenicity. Based on long-term stability data, foam dried formulations exhibited a shelf life at 4, 25 and 37°C of >2, 1.5 years and 4.5 months, respectively. Foam dried LAIV Type-B manufactured using the same formulation and process parameters as H1N1 were imparted with a similar level of stability. Foam drying processing methods with appropriate selection of formulation components can produce an order of magnitude improvement in LAIV stability over other drying methods.

  8. Menu Cycles.

    ERIC Educational Resources Information Center

    Clayton, Alfred; Almony, John

    The curriculum guide for commercial foods instruction is designed to aid the teacher in communicating the importance of menu cycles in commercial food production. It also provides information about the necessary steps in getting food from the raw form to the finished product, and then to the consumer. In addition to providing information on how to…

  9. Dry dock no. 4. Service Building between dry docks 4 ...

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

    Dry dock no. 4. Service Building between dry docks 4 and 5. Floor plans (Navy Yard Public Works Office 1941). In files of Cushman & Wakefield, building 501. Philadelphia Naval Business Center. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Service Building, Dry Docks No. 4 & 5, League Island, Philadelphia, Philadelphia County, PA

  10. Dry Cleaning Sector (NAICS 8123)

    EPA Pesticide Factsheets

    The dry cleaning sector includes establishments engaged in providing laundry services and industrial launderers. Find environmental regulatory information for perchloroethylene (PERC) cleaners as well as hazardous waste regulations for dry cleaners.

  11. Simple Solutions for Dry Eye

    MedlinePlus

    ... are more concentrated in the tear film of dry eye patients. In hot weather, sleep with the windows shut and keep cool with air conditioning. • Dry eye patients often develop or aggravate allergies. An ...

  12. Drying hardwoods with impinging jets.

    Treesearch

    Howard N. Rosen

    1980-01-01

    Silver maple, yellow poplar, and black walnut lumber was dried in a prototype jet dryer over a range of temperatures from 120 degrees to 400 degrees Fahrenheit and air velocities from 1,000 to 9,000 fpm. Different drying schedules were developed for each type of wood. The quality of the jet-dried lumber was good and compared favorably with kiln-dried lumber.

  13. Microwave drying of wood strands

    Treesearch

    Guanben Du; Siqun Wang; Zhiyong Cai

    2005-01-01

    Characteristics of microwave drying of wood strands with different initial moisture contents and geometries were investigated using a commercial small microwave oven under different power inputs. Temperature and moisture changes along with the drying efficiency were examined at different drying scenarios. Extractives were analyzed using gas chromatography=mass...

  14. Endoscope drying and its pitfalls.

    PubMed

    Kovaleva, J

    2017-07-17

    Inadequate drying of endoscope channels is a possible cause of replication and survival of remaining pathogens during storage. The presence during storage of potentially contaminated water in endoscope channels may promote bacterial proliferation and biofilm formation. An incomplete drying procedure or lack of drying and not storing in a vertical position are the most usual problems identified during drying and endoscope storage. Inadequate drying and storage procedures, together with inadequate cleaning and disinfection, are the most important sources of endoscope contamination and post-endoscopic infection. Flexible endoscopes may be dried in automated endoscope reprocessors (AERs), manually, or in drying/storage cabinets. Flushing of the endoscope channels with 70-90% ethyl or isopropyl alcohol followed by forced air drying is recommended by several guidelines. Current guidelines recommend that flexible endoscopes are stored in a vertical position in a closed, ventilated cupboard. Drying and storage cabinets have a drying system that circulates and forces the dry filtered air through the endoscope channels. Endoscope reprocessing guidelines are inconsistent with one another or give no exact recommendations about drying and storage of flexible endoscopes. There is no conclusive evidence on the length of time endoscopes can be safely stored before requiring re-disinfection and before they pose a contamination risk. To minimize the risk of disease transmission and nosocomial infection, modification and revision of guidelines are recommended as required to be consistent with one another. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

  15. Desiccant drying of gas pipelines

    SciTech Connect

    LaCasse, G.A.; Ingvordsen, T.

    1988-09-01

    Prevention of hydrates buildup and corrosion in gas pipelines after hydrostatic testing is increasingly important to those in the gas industry. This paper outlines a dry air method used in Denmark for drying gas pipelines. The psychrometric principles, drying method, and humidity measurements are described.

  16. Microwave applications to rock specimen drying in laboratory

    NASA Astrophysics Data System (ADS)

    Park, Jihwan; Park, Hyeong-Dong

    2014-05-01

    Microwave heating is the process in which electromagnetic wave with 300 MHz - 300 GHz heats dielectric material. Although in the beginning microwave was mainly used in food industry to cook or heat the food, it soon became clear that microwave had a large potential for other applications. It was thus introduced in geological fields of investigation like mineral processing, oil sand and oil shale extraction, soil remediation, waste treatment. However, the drying techniques using microwave was rarely treated in geology field. According to the ISRM suggested methods, experimental rock specimens in laboratory test were dried in 105°C oven for a period of at least 24 hours. In this method, hot air transmits heats to material by means of thermal conduction, and the heat was transferred from the surface to the inside of the rock specimens. The thermal gradient and moisture gradient can deteriorate the specimens, and energy can be wasted in bulk heating the specimens. The aim of our study was to compare physical property, microstructural property, and energy efficiency between microwave drying method and conventional oven drying method, and to suggest new method for rock drying. Granite, basalt, and sandstone were selected as specimens and were made in cylinder shape with 54 mm diameter. To compare two different methods, one set of saturated specimens were dried in 105°C conventional oven and the other set of saturated specimens were dried in microwave oven. After dried, the specimens were cooled and saturated in 20°C water 48 hours. The saturation-drying were repeated 50 cycles, and the physical property and microstructural property were measured every 10 cycles. Absorption and elastic wave velocity were measured to investigate the change of physical property, and microscope image and X-ray computed tomography image were obtained to investigate the change of microstructural property of rock specimens. The electricity consumption of conventional oven and microwave oven

  17. Effect of wetting and drying on the bioavailability of organic compounds sequestered in soil

    SciTech Connect

    White, J.C.; Quinones-Rivera, A.; Alexander, M.

    1998-12-01

    A study was conducted to determine whether cycles of wetting and drying alter the availability of organic compounds that have aged in soil. Subjecting soil to wetting-and drying cycles during periods of aging <60 d decreased the biodegradability, extractability, and uptake by earthworms of phenanthrene and reduced the extractability of di(2-ethylhexyl) phthalate (DEHP) sequestered in soil compared with soil aged at constant moisture. The mineralization of sequestered DEHP was greater in soil that was wet and dried during a 41-d period of aging than in soil incubated at constant moisture. Wetting and drying soil during periods of aging of 100 or more days had no effect on the biodegradability or assimilation by Eisenia foetida of sequestered phenanthrene and DEHP. Subjecting soil containing previously sequestered phenanthrene to one, three, or four wetting-and-drying cycles increased the biodegradability of the compound. The extractability of sequestered phenanthrene was greater in soil that was wet and dried once after aging than in soil maintained at constant moisture, but three wetting-and-drying cycles did not affect extractability. The biodegradability of sequestered DEHP was unaffected by wetting and drying. The authors suggest that wetting and drying may be useful in the remediation of contaminated soils.

  18. Terrestrial Planets Accreted Dry

    NASA Astrophysics Data System (ADS)

    Albarede, F.; Blichert-Toft, J.

    2007-12-01

    Plate tectonics shaped the Earth, whereas the Moon is a dry and inactive desert. Mars probably came to rest within the first billion years of its history, and Venus, although internally very active, has a dry inferno for its surface. The strong gravity field of a large planet allows for an enormous amount of gravitational energy to be released, causing the outer part of the planetary body to melt (magma ocean), helps retain water on the planet, and increases the pressure gradient. The weak gravity field and anhydrous conditions prevailing on the Moon stabilized, on top of its magma ocean, a thick buoyant plagioclase lithosphere, which insulated the molten interior. On Earth, the buoyant hydrous phases (serpentines) produced by reactions between the terrestrial magma ocean and the wet impactors received from the outer Solar System isolated the magma and kept it molten for some few tens of million years. The elemental distributions and the range of condensation temperatures show that the planets from the inner Solar System accreted dry. The interior of planets that lost up to 95% of their K cannot contain much water. Foundering of their wet surface material softened the terrestrial mantle and set the scene for the onset of plate tectonics. This very same process may have removed all the water from the surface of Venus 500 My ago and added enough water to its mantle to make its internal dynamics very strong and keep the surface very young. Because of a radius smaller than that of the Earth, not enough water could be drawn into the Martian mantle before it was lost to space and Martian plate tectonics never began. The radius of a planet therefore is the key parameter controlling most of its evolutional features.

  19. Electrohydrodynamic drying of carrot slices.

    PubMed

    Ding, Changjiang; Lu, Jun; Song, Zhiqing

    2015-01-01

    Carrots have one of the highest levels of carotene, and they are rich in vitamins, fiber and minerals. However, since fresh carrots wilt rapidly after harvest under inappropriate storage conditions, drying has been used to improve their shelf life and retain nutritional quality. Therefore, to further investigate the potential of this method, carrot slices were dried in an EHD system in order to study the effect of different voltages on drying rate. As measures of quality, carotene content and rehydration ratio were, respectively, compared against the conventional oven drying regime. Carotene, the main component of the dried carrot, and rehydration characteristics of the dried product can both indicate quality by physical and chemical changes during the drying process. Mathematical modeling and simulation of drying curves were also performed, using root mean square error, reduced mean square of the deviation and modeling efficiency as the primary criteria to select the equation that best accounts for the variation in the drying curves of the dried samples. Theoretically, the Page model was best suited for describing the drying rate curve of carrot slices at 10kV to 30kV. Experimentally, the drying rate of carrots was notably greater in the EHD system when compared to control, and quality, as determined by carotene content and rehydration ratio, was also improved when compared to oven drying. Therefore, this work presents a facile and effective strategy for experimentally and theoretically determining the drying properties of carrots, and, as a result, it provides deeper insight into the industrial potential of the EHD drying technique.

  20. Electrohydrodynamic Drying of Carrot Slices

    PubMed Central

    Ding, Changjiang; Lu, Jun; Song, Zhiqing

    2015-01-01

    Carrots have one of the highest levels of carotene, and they are rich in vitamins, fiber and minerals. However, since fresh carrots wilt rapidly after harvest under inappropriate storage conditions, drying has been used to improve their shelf life and retain nutritional quality. Therefore, to further investigate the potential of this method, carrot slices were dried in an EHD system in order to study the effect of different voltages on drying rate. As measures of quality, carotene content and rehydration ratio were, respectively, compared against the conventional oven drying regime. Carotene, the main component of the dried carrot, and rehydration characteristics of the dried product can both indicate quality by physical and chemical changes during the drying process. Mathematical modeling and simulation of drying curves were also performed, using root mean square error, reduced mean square of the deviation and modeling efficiency as the primary criteria to select the equation that best accounts for the variation in the drying curves of the dried samples. Theoretically, the Page model was best suited for describing the drying rate curve of carrot slices at 10kV to 30kV. Experimentally, the drying rate of carrots was notably greater in the EHD system when compared to control, and quality, as determined by carotene content and rehydration ratio, was also improved when compared to oven drying. Therefore, this work presents a facile and effective strategy for experimentally and theoretically determining the drying properties of carrots, and, as a result, it provides deeper insight into the industrial potential of the EHD drying technique. PMID:25874695

  1. Drying of Complex Suspensions

    NASA Astrophysics Data System (ADS)

    Xu, Lei; Bergès, Alexis; Lu, Peter J.; Studart, André R.; Schofield, Andrew B.; Oki, Hidekazu; Davies, Simon; Weitz, David A.

    2010-03-01

    We investigate the 3D structure and drying dynamics of complex mixtures of emulsion droplets and colloidal particles, using confocal microscopy. Air invades and rapidly collapses large emulsion droplets, forcing their contents into the surrounding porous particle pack at a rate proportional to the square of the droplet radius. By contrast, small droplets do not collapse, but remain intact and are merely deformed. A simple model coupling the Laplace pressure to Darcy’s law correctly estimates both the threshold radius separating these two behaviors, and the rate of large-droplet evacuation. Finally, we use these systems to make novel hierarchical structures.

  2. Dry removal of asbestos.

    PubMed

    Elias, J D

    1981-08-01

    A method for the dry removal of friable asbestos has been developed. The Workplace Safety and Health Branch in Manitoba's Limited have co-operated in the production of an improved procedure. It was employed for the first time in the fall of 1979 when the Industrial Hygiene Section was asked for advice about removal of asbestos from a Winnipeg School Division warehouse. Fans were used to maintain the work area under negative pressure to prevent the spread of asbestos throughout the building. The exhaust air was filtered to prevent environmental contamination, and special precautions were taken to protect workers.

  3. Method of drying articles

    DOEpatents

    Janney, Mark A.; Kiggans, Jr., James O.

    1999-01-01

    A method of drying a green particulate article includes the steps of: a. Providing a green article which includes a particulate material and a pore phase material, the pore phase material including a solvent; and b. contacting the green article with a liquid desiccant for a period of time sufficient to remove at least a portion of the solvent from the green article, the pore phase material acting as a semipermeable barrier to allow the solvent to be sorbed into the liquid desiccant, the pore phase material substantially preventing the liquid desiccant from entering the pores.

  4. Method of drying articles

    DOEpatents

    Janney, M.A.; Kiggans, J.O. Jr.

    1999-03-23

    A method of drying a green particulate article includes the steps of: (a) Providing a green article which includes a particulate material and a pore phase material, the pore phase material including a solvent; and (b) contacting the green article with a liquid desiccant for a period of time sufficient to remove at least a portion of the solvent from the green article, the pore phase material acting as a semipermeable barrier to allow the solvent to be sorbed into the liquid desiccant, the pore phase material substantially preventing the liquid desiccant from entering the pores. 3 figs.

  5. Drying and decontamination of raw pistachios with sequential infrared drying, tempering and hot air drying.

    PubMed

    Venkitasamy, Chandrasekar; Brandl, Maria T; Wang, Bini; McHugh, Tara H; Zhang, Ruihong; Pan, Zhongli

    2017-04-04

    Pistachio nuts have been associated with outbreaks of foodborne disease and the industry has been impacted by numerous product recalls due to contamination with Salmonella enterica. The current hot air drying of pistachios has low energy efficiency and drying rates, and also does not guarantee the microbial safety of products. In the study described herein, dehulled and water-sorted pistachios with a moisture content (MC) of 38.14% (wet basis) were dried in a sequential infrared and hot air (SIRHA) drier to <9% MC. The decontamination efficacy was assessed by inoculating pistachios with Enterococcus faecium, a surrogate of Salmonella enterica used for quality control in the almond industry. Drying with IR alone saved 105min (34.4%) of drying time compared with hot air drying. SIRHA drying of pistachios for 2h with infrared (IR) heat followed by tempering at a product temperature of 70°C for 2h and then by hot air drying shortened the drying time by 40min (9.1%) compared with drying by hot air only. This SIRHA method also reduced the E. faecium cell population by 6.1-logCFU/g kernel and 5.41-logCFU/g shell of pistachios. The free fatty acid contents of SIRHA dried pistachios were on par with that of hot air dried samples. Despite significant differences in peroxide values (PV) of pistachio kernels dried with the SIRHA method compared with hot air drying at 70°C, the PV were within the permissible limit of 5Meq/kg for edible oils. Our findings demonstrate the efficacy of SIRHA drying in achieving simultaneous drying and decontamination of pistachios. Published by Elsevier B.V.

  6. Advances in drying: Volume 4

    SciTech Connect

    Mujumdar, A.S.

    1987-01-01

    Topics covered in this volume include recent thoughts in modeling of drying phenomena, use of computers in rational design of drying particulates, recent advances in drying of wood, and heat/mass transfer phenomena in drying of solids. As the readers will no doubt notice, special effort is made to ensure the truly international nature of the contents of this serial publication. As existing knowledge on drying and dryers becomes more widely and readily accessible, it is expected that more and more dryers will be designed rationally rather than built solely with the benefit of empiricism.

  7. Drying and decontamination of pistachios with sequential infrared drying, tempering and hot air drying

    USDA-ARS?s Scientific Manuscript database

    The pistachio industry is in need of improved drying technology as the current hot air drying has low energy efficiency and drying rate and high labor cost and also does not produce safe products against microbial contamination. In the current study, dehulled and water- sorted pistachios with a mois...

  8. Robotic dry stripping of airframes - Phase II

    NASA Astrophysics Data System (ADS)

    Pauli, Robert A.; Wittenberg, Art M.

    1989-03-01

    This paper describes a program for the development of a dust-free closed-cycle robotic system for dry stripping of airframes, designed to insure dust-free work environment and reduce plastic-media loss, the contamination risk, and the media inventory requirement. Phase I of the program involved building a prototype of the proposed robotic arm and its dust enclosure to prove basic automation concepts, showing reasonable paint removal rate from a curved surface, and establishing that the process is dust-free and recovers plastic media in a closed-cycle fashion. This paper contains calculations on the effect of different blasting parameters in order to determine optimum values required for the completion of Phase I. Also presented is the progress achieved by the Phase II of the program, which is to prove the total concept by building the complete system and demonstrating its capability.

  9. Dry reforming of hydrocarbon feedstocks

    SciTech Connect

    Shah, Yatish T.; Gardner, Todd H.

    2014-09-25

    Developments in catalyst technology for the dry reforming of hydrocarbon feedstocks are reviewed for methane, higher hydrocarbons and alcohols. Thermodynamics, mechanisms and the kinetics of dry reforming are also reviewed. The literature on Ni catalysts, bi-metallic Ni catalysts and the role of promoters on Ni catalysts is critically evaluated. The use of noble and transitional metal catalysts for dry reforming is discussed. The application of solid oxide and metal carbide catalysts to dry reforming is also evaluated. Finally, various mechanisms for catalyst deactivation are assessed. This review also examines the various process related issues associated with dry reforming such as its application and heat optimization. Novel approaches such as supercritical dry reforming and microwave assisted dry reforming are briefly expanded upon.

  10. Deep layer malt drying modelling

    SciTech Connect

    Lopez, A.; Virseda, P.; Martinez, G.; Llorca, M.

    1997-05-01

    In malt production drying operation plays an important role in the total processing cost, however there are not many studies on malt drying modeling and optimization. In this paper a deep layer malt drying mathematical model in the form of four partial differential equations is presented. To determine drying constants, malt thin layer drying experiments at several air temperatures and relative humidities were made. The model were validated at industrial scale. The greatest energy savings, approximately 5.5% in fuel and 7.5% in electric energy, were obtained by an additional (and increased) air recirculation, which is carried out during the last 6 hours of the drying process and a significant decrease of air flow-rate during the last 6 hours of the drying process.

  11. Dry EEG Electrodes

    PubMed Central

    Lopez-Gordo, M. A.; Sanchez-Morillo, D.; Valle, F. Pelayo

    2014-01-01

    Electroencephalography (EEG) emerged in the second decade of the 20th century as a technique for recording the neurophysiological response. Since then, there has been little variation in the physical principles that sustain the signal acquisition probes, otherwise called electrodes. Currently, new advances in technology have brought new unexpected fields of applications apart from the clinical, for which new aspects such as usability and gel-free operation are first order priorities. Thanks to new advances in materials and integrated electronic systems technologies, a new generation of dry electrodes has been developed to fulfill the need. In this manuscript, we review current approaches to develop dry EEG electrodes for clinical and other applications, including information about measurement methods and evaluation reports. We conclude that, although a broad and non-homogeneous diversity of approaches has been evaluated without a consensus in procedures and methodology, their performances are not far from those obtained with wet electrodes, which are considered the gold standard, thus enabling the former to be a useful tool in a variety of novel applications. PMID:25046013

  12. Effect of season on estrous cycle of Yankasa sheep.

    PubMed

    Igono, M O; Molokwu, E C; Aliu, Y O

    1982-09-01

    An investigation was conducted to establish the effects of harmattan and hot-dry season on estrous cycle length, onset, and duration of estrus in Yankasa sheep indigenous to the Nigerian guinea savanna zone. Mean cycle lengths were 16.8 +/- 0.58 and 16.4 +/- 0.53 days during harmattan and hot-dry seasons, respectively; short cycles, 5-13 days, and long cycles, 21 to 30 days, were observed during both seasons. During the harmattan season, 57.1% of estrus began at night while 70% started at night during the hot-dry season. The duration of normal estrus observed during the harmattan, 33.6 +/- 5.87h, significantly decreased (P0.05) during the hot-dry season (24.0 +/- 5.45h). It is suggested that twice daily observation at 12-hour intervals will suffice to detect estrus in this breed of sheep.

  13. Steam drying -- Modeling and applications

    SciTech Connect

    Wimmerstedt, R.; Hager, J.

    1996-08-01

    The concept of steam drying originates from the mid of the last century. However, a broad industrial acceptance of the technique has so far not taken place. The paper deals with modelling the steam drying process and applications of steam drying within certain industrial sectors where the technique has been deemed to have special opportunities. In the modelling section the mass and heat transfer processes are described along with equilibrium, capillarity and sorption phenomena occurring in porous materials during the steam drying process. In addition existing models in the literature are presented. The applications discussed involve drying of fuels with high moisture contents, cattle feed exemplified by sugar beet pulp, lumber, paper pulp, paper and sludges. Steam drying is compared to flue gas drying of biofuels prior to combustion in a boiler. With reference to a current installation in Sweden, the exergy losses, as manifested by loss of co-generation capacity, are discussed. The energy saving potential when using steam drying of sugar beet pulp as compared to other possible plant configurations is demonstrated. Mechanical vapor recompression applied to steam drying is analyzed with reference to reported data from industrial plants. Finally, environmental advantages when using steam drying are presented.

  14. Dry aging of beef; Review.

    PubMed

    Dashdorj, Dashmaa; Tripathi, Vinay Kumar; Cho, Soohyun; Kim, Younghoon; Hwang, Inho

    2016-01-01

    The present review has mainly focused on the specific parameters including aging (aging days, temperature, relative humidity, and air flow), eating quality (flavor, tenderness and juiciness), microbiological quality and economic (shrinkage, retail yields and cost) involved beef dry aging process. Dry aging is the process where beef carcasses or primal cuts are hanged and aged for 28 to 55 d under controlling environment conditions in a refrigerated room with 0° to 4 °C and with relative humidity of 75 to 80 %. However there are various opinions on dry aging procedures and purveyors of such products are passionate about their programs. Recently, there has been an increased interest in dry aging process by a wider array of purveyors and retailers in the many countries. Dry aging process is very costly because of high aging shrinkage (6 to15 %), trims loss (3 to 24 %), risk of contamination and the requirement of highest grades meat with. The packaging in highly moisture-permeable bag may positively impact on safety, quality and shelf stability of dry aged beef. The key effect of dry aging is the concentration of the flavor that can only be described as "dry-aged beef". But the contribution of flavor compounds of proteolysis and lipolysis to the cooked dry aged beef flavor is not fully known. Also there are limited scientific studies of aging parameters on the quality and palatability of dry aged beef.

  15. Strengthening contrast between precipitation in tropical wet and dry regions

    NASA Astrophysics Data System (ADS)

    Polson, D.; Hegerl, G. C.

    2017-01-01

    The wet-gets-wetter, dry-gets-drier paradigm (WWDD) is widely used to summarize the expected response of the hydrological cycle to global warming. While some studies find that changes in observations and climate models support the WWDD paradigm, others find that it is more complicated at local scales and over land. This discrepancy is partly explained by differences in model climatologies and by movement of the wet and dry regions. Here we show that by tracking changes in wet and dry regions as they shift over the tropics and vary in models, mean precipitation changes follow the WWDD pattern in observations and models over land and ocean. However, this signal is reduced and disappears in model dry regions, when these factors are not accounted for. Accounting for seasonal and interannual shifts of the regions and climatological differences between models reduces uncertainty in predictions of future precipitation changes and makes these changes detectable earlier.

  16. A commercially viable solar wood drying kiln system

    SciTech Connect

    Vore, J.B. de; Denny, G.S.; Harper, T.S.

    1999-01-01

    The purpose of the study was to create a totally passive solar wood drying kiln that would dry lumber to 9% moisture content in a reasonable amount of time. A series of modifications led to a kiln design that dried freshly-cut lumber to 8% in a 29-day period with no case hardening or cracking. Air speed, internal and external temperatures and relative humidity levels were measured at 5-minute intervals. The average temperature inside the kiln was 12% higher with relative humidity levels 19% lower than outside the kiln. It is hypothesized that the daily cycles of heating and cooling permitted the interior moisture of the wood to reach the surface through diffusion, thus lessening stress and speeding drying of the lumber.

  17. Dry ice blasting

    NASA Astrophysics Data System (ADS)

    Lonergan, Jeffrey M.

    1992-04-01

    As legal and societal pressures against the use of hazardous waste generating materials has increased, so has the motivation to find safe, effective, and permanent replacements. Dry ice blasting is a technology which uses CO2 pellets as a blasting medium. The use of CO2 for cleaning and stripping operations offers potential for significant environmental, safety, and productivity improvements over grit blasting, plastic media blasting, and chemical solvent cleaning. Because CO2 pellets break up and sublime upon impact, there is no expended media to dispose of. Unlike grit or plastic media blasting which produce large quantities of expended media, the only waste produced by CO2 blasting is the material removed. The quantity of hazardous waste produced, and thus the cost of hazardous waste disposal is significantly reduced.

  18. Evaluation of the dry mouth patient.

    PubMed

    Zunt, Susan

    2007-01-01

    This paper examines the questions "who is the dry mouth patient and how is the dry mouth patient evaluated"? It reviews the clinical features of dry mouth. It presents current treatment options for dry mouth care.

  19. Dry Ice Etches Terrain

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1

    Every year seasonal carbon dioxide ice, known to us as 'dry ice,' covers the poles of Mars. In the south polar region this ice is translucent, allowing sunlight to pass through and warm the surface below. The ice then sublimes (evaporates) from the bottom of the ice layer, and carves channels in the surface.

    The channels take on many forms. In the subimage shown here (figure 1) the gas from the dry ice has etched wide shallow channels. This region is relatively flat, which may be the reason these channels have a different morphology than the 'spiders' seen in more hummocky terrain.

    Observation Geometry Image PSP_003364_0945 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 15-Apr-2007. The complete image is centered at -85.4 degrees latitude, 104.0 degrees East longitude. The range to the target site was 251.5 km (157.2 miles). At this distance the image scale is 25.2 cm/pixel (with 1 x 1 binning) so objects 75 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel . The image was taken at a local Mars time of 06:57 PM and the scene is illuminated from the west with a solar incidence angle of 75 degrees, thus the sun was about 15 degrees above the horizon. At a solar longitude of 219.6 degrees, the season on Mars is Northern Autumn.

  20. Dry Ice Etches Terrain

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1

    Every year seasonal carbon dioxide ice, known to us as 'dry ice,' covers the poles of Mars. In the south polar region this ice is translucent, allowing sunlight to pass through and warm the surface below. The ice then sublimes (evaporates) from the bottom of the ice layer, and carves channels in the surface.

    The channels take on many forms. In the subimage shown here (figure 1) the gas from the dry ice has etched wide shallow channels. This region is relatively flat, which may be the reason these channels have a different morphology than the 'spiders' seen in more hummocky terrain.

    Observation Geometry Image PSP_003364_0945 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 15-Apr-2007. The complete image is centered at -85.4 degrees latitude, 104.0 degrees East longitude. The range to the target site was 251.5 km (157.2 miles). At this distance the image scale is 25.2 cm/pixel (with 1 x 1 binning) so objects 75 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel . The image was taken at a local Mars time of 06:57 PM and the scene is illuminated from the west with a solar incidence angle of 75 degrees, thus the sun was about 15 degrees above the horizon. At a solar longitude of 219.6 degrees, the season on Mars is Northern Autumn.

  1. Dry Processing of Used Nuclear Fuel

    SciTech Connect

    K. M. Goff; M. F. Simpson

    2009-09-01

    Dry (non-aqueous) separations technologies have been used for treatment of used nuclear fuel since the 1960s, and they are still being developed and demonstrated in many countries. Dry technologies offer potential advantages compared to traditional aqueous separations including: compactness, resistance to radiation effects, criticality control benefits, compatibility with advanced fuel types, and ability to produce low purity products. Within the Department of Energy’s Advanced Fuel Cycle Initiative, an electrochemical process employing molten salts is being developed for recycle of fast reactor fuel and treatment of light water reactor oxide fuel to produce a feed for fast reactors. Much of the development of this technology is based on treatment of used Experimental Breeder Reactor II (EBR-II) fuel, which is metallic. Electrochemical treatment of the EBR-II fuel has been ongoing in the Fuel Conditioning Facility, located at the Materials and Fuel Complex of Idaho National Laboratory since 1996. More than 3.8 metric tons of heavy metal of metallic fast reactor fuel have been treated using this technology. This paper will summarize the status of electrochemical development and demonstration activities with used nuclear fuel, including high-level waste work. A historic perspective on the background of dry processing will also be provided.

  2. Dry season refugia of malaria-transmitting mosquitoes in a dry savannah zone of east Africa.

    PubMed

    Charlwood, J D; Vij, R; Billingsley, P F

    2000-06-01

    Dry season survival of Anopheles funestus, Anopheles gambiae and Anopheles arabiensis in the Kilombero valley a dry savannah zone of east Africa, was investigated with over 400 collections from 23 areas, covering 300 sq km of the valley. Anopheles gambiae was found only in association with humans, in forested areas of high annual rainfall, while An. funestus occurred at high densities at the valley edge where large non-moving bodies of water remained. A large population of An. arabiensis was present along the river system throughout the middle of the valley, and mosquitoes probably derived from this population were occasionally caught in villages bordering the valley. No evidence was obtained of aestivation in any mosquito species. Anopheles gambiae was the most long lived, 6.3% compared to 2.0% of the An. arabiensis and 4% of the An. funestus surviving for four or more gonotrophic cycles, the approximate duration of the extrinsic cycle of most malaria parasites. Oocysts of malaria parasites were found in 5.4% of An. funestus and 2.3% of An. arabiensis from villages. Oocyst rates in An. funestus differed significantly between areas but not between houses within areas. Anopheles funestus is the most important dry season malaria vector in the valley, and remains in foci closely associated with groups of houses. All three species survive at high densities but as otherwise hidden refugia populations.

  3. Terrestrial Carbon Cycle Variability.

    PubMed

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2, temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y (-1)) with respect to a large and uncertain background (123 +/- 4 Pg-C y (-1)), and

  4. Terrestrial Carbon Cycle Variability

    PubMed Central

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2, temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y -1) with respect to a large and uncertain background (123 +/- 4 Pg-C y -1), and

  5. Current Clinical Trials in Dry AMD and the Definition of Appropriate Clinical Outcome Measures.

    PubMed

    Yehoshua, Zohar; Rosenfeld, Philip J; Albini, Thomas A

    2011-05-01

    Currently, there is no proven drug treatment for dry age-related macular degeneration (AMD). Several different treatment strategies are being investigated, including complement inhibition, neuroprotection, and visual cycle inhibitors, and novel clinical trial endpoints are being explored. Studies have identified genetic predispositions for dry AMD associated with complement dysfunction. Consequently, complement-based therapeutic treatment modalities are promising.

  6. Former land-use and tree species affect nitrogen oxide emissions from a tropical dry forest.

    Treesearch

    Heather Erickson; Eric A. Davidson; Michael Keller

    2002-01-01

    Species composition in successional dry forests in the tropics varies widely, but the effect of this variation on biogeochemical processes is not well known. We examined fluxes of N oxides (nitrous and nitric oxide), soil N cycling, and litter chemistry (C/N ratio) in four successional dry forests on similar soils in western Puerto Rico with differing species...

  7. Improvements In solar dry kiln design

    Treesearch

    E. M. Wengert

    1971-01-01

    Interest in solar drying of lumber has increased in recent years because previous results had indicated that: Drying times are shorter and final moisture contents are lower in solar drying than in air drying; much less lumber degrade occurs in solar drying when compared to air drying; and the cost of energy is less in solar drying than in kiln drying. Work in the field...

  8. Nutrient returns from field-drying of logging residue

    SciTech Connect

    Johnson, James E.; Smith, D.W.; Stuart, W.B.

    1985-01-01

    Increasing interest in utilizing logging residue for fuel has caused concern over additional nutrient removals from the site. On-site drying of the residue may have an ameliorative effect due to nutrient returns during the drying process. To determine nutrient returns from field-dried logging residue, four red maple (Acer rubrum L.) and chestnut oak (Quercus prinus L.) trees were felled and skidded into a 2-ha clearcut area. Twig and leaf samples were collected immediately after cutting and after 2, 4, 8, and 16 weeks of field-drying. Declines in both P and K concentrations in the leaves and twigs were noted over the drying period. When nutrient returns were computed on a kg ha/sup -1/ basis the following returns were observed after 16 weeks of drying: N, P, K, Ca, and Mg were 37, 2, 34, 20, and 2 kg ha/sup -1/, respectively. These amounts are similar to those cycled annually in litter-fall in Appalachian mixed oak stands, which indicates that from a nutrient conservation standpoint, summer logging followed by field-drying may be comparable to winter (leaf-off) logging in these stands.

  9. Comparison of drying characteristic and uniformity of banana cubes dried by pulse-spouted microwave vacuum drying, freeze drying and microwave freeze drying.

    PubMed

    Jiang, Hao; Zhang, Min; Mujumdar, Arun S; Lim, Rui-Xin

    2014-07-01

    To overcome the flaws of high energy consumption of freeze drying (FD) and the non-uniform drying of microwave freeze drying (MFD), pulse-spouted microwave vacuum drying (PSMVD) was developed. The results showed that the drying time can be dramatically shortened if microwave was used as the heating source. In this experiment, both MFD and PSMVD could shorten drying time by 50% as compared to the FD process. Depending on the heating method, MFD and PSMVD dried banana cubes showed trends of expansion while FD dried samples demonstrated trends of shrinkage. Shrinkage also brought intensive structure and highest fracturability of all three samples dried by different methods. The residual ascorbic acid content of PSMVD dried samples can be as high as in FD dried samples, which were superior to MFD dried samples. The tests confirmed that PSMVD could bring about better drying uniformity than MFD. Besides, compared with traditional MFD, PSMVD can provide better extrinsic feature, and can bring about improved nutritional features because of the higher residual ascorbic acid content. © 2013 Society of Chemical Industry.

  10. [Tear osmolarity and dry eye].

    PubMed

    Pan, Shi-yin; Xiao, Xiang-hua; Wang, Yang-zheng; Liu, Xian-ning; Zhu, Xiu-ping

    2011-05-01

    Dry eye is a common eye disease, and its incidence rate has been escalating. The increased tear osmolarity is one of the main reasons for complaint, damage and inflammation of dry eye patients. With the breakthrough of testing technology for tear osmolarity, more research and application of tear osmolarity was reported, and papers on tear osmolarity of normal eye and dry eye in different regions were also published. In this article, the progress of the tear osmolarity research, the range of tear osmolarity and its application in diagnosis and therapy of dry eye was introduced, and the prospect for the clinical application of hypotonic artificial tears was also discussed.

  11. Space Technology for Crop Drying

    NASA Technical Reports Server (NTRS)

    1980-01-01

    McDonnell Douglas came up with a new method of drying agricultural crops derived from vacuum chamber technology called MIVAC, a compression of microwave vacuum drying system. A distant cousin of the home microwave oven, MIVAC dries by means of electrically- generated microwaves introduced to a crop-containing vacuum chamber. Microwaves remove moisture quickly and the very low pressure atmosphere in the chamber permits effective drying at much lower than customary temperatures. Thus energy demand is doubly reduced by lower heat requirement and by the shorter time electric power is needed.

  12. Sessile nanofluid droplet drying.

    PubMed

    Zhong, Xin; Crivoi, Alexandru; Duan, Fei

    2015-03-01

    Nanofluid droplet evaporation has gained much audience nowadays due to its wide applications in painting, coating, surface patterning, particle deposition, etc. This paper reviews the drying progress and deposition formation from the evaporative sessile droplets with the suspended insoluble solutes, especially nanoparticles. The main content covers the evaporation fundamental, the particle self-assembly, and deposition patterns in sessile nanofluid droplet. Both experimental and theoretical studies are presented. The effects of the type, concentration and size of nanoparticles on the spreading and evaporative dynamics are elucidated at first, serving the basis for the understanding of particle motion and deposition process which are introduced afterward. Stressing on particle assembly and production of desirable residue patterns, we express abundant experimental interventions, various types of deposits, and the effects on nanoparticle deposition. The review ends with the introduction of theoretical investigations, including the Navier-Stokes equations in terms of solutions, the Diffusion Limited Aggregation approach, the Kinetic Monte Carlo method, and the Dynamical Density Functional Theory. Nanoparticles have shown great influences in spreading, evaporation rate, evaporation regime, fluid flow and pattern formation of sessile droplets. Under different experimental conditions, various deposition patterns can be formed. The existing theoretical approaches are able to predict fluid dynamics, particle motion and deposition patterns in the particular cases. On the basis of further understanding of the effects of fluid dynamics and particle motion, the desirable patterns can be obtained with appropriate experimental regulations. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Forward Osmosis Brine Drying

    NASA Technical Reports Server (NTRS)

    Flynn, Michael; Shaw, Hali; Hyde, Deirdre; Beeler, David; Parodi, Jurek

    2015-01-01

    The Forward Osmosis Brine Drying (FOBD) system is based on a technique called forward osmosis (FO). FO is a membrane-based process where the osmotic potential between brine and a salt solution is equalized by the movement of water from the brine to the salt solution. The FOBD system is composed of two main elements, the FO bag and the salt regeneration system. This paper discusses the results of testing of the FO bag to determine the maximum water recovery ratio that can be attained using this technology. Testing demonstrated that the FO bag is capable of achieving a maximum brine water recovery ratio of the brine of 95%. The equivalent system mass was calculated to be 95 kg for a feed similar to the concentrated brine generated on the International Space Station and 86 kg for an Exploration brine. The results have indicated that the FOBD can process all the brine for a one year mission for between 11% to 10% mass required to bring the water needed to make up for water lost in the brine if not recycled. The FOBD saves 685 kg and when treating the International Space Station brine and it saves 829 kg when treating the Exploration brine. It was also demonstrated that saturated salt solutions achieve a higher water recovery ratios than solids salts do and that lithium chloride achieved a higher water recovery ratio than sodium chloride.

  14. Dry sump crankcase

    SciTech Connect

    Berger, A.H.; Dichi, R.E.

    1987-06-23

    A dry sump type crankcase is described for an automotive type internal combustion engine having an intake manifold and a positive crankcase ventilation (PCV) system for automatically and continuously ventilating the crankcase. The system includes an essentially atmospheric pressure fresh air inlet to the engine passing air through to the crankcase and a connection from the oil pan to the vacuum in the intake manifold establishing a constant flow of crankcase vapors. The oil pan has a baffle partitioning it into an inner oil collecting funnel-like crankcase cavity and an outer oil reservoir. The inner cavity has an opening at its lower-most point for communication of oil with the reservoir. The opening is of a controlled vertical height for creating a pressure differential across the baffle during operation of the engine. Means connects the inner cavity to the air inlet pressure side of the PCV System while connecting the reservoir to the vacuum side of the PCV system for establishing a constant pressure differential across the baffle sufficient to displace the oil against gravity and maintain the oil level in the crankcase during operation of the engine at the height of the opening in the baffle. Gravity causes the oil to seek a level higher than the opening upon shutdown of the engine and the consequential decay of vacuum in the intake manifold.

  15. Staying dry under water

    NASA Astrophysics Data System (ADS)

    Jones, Paul; Cruz-Chu, Eduardo; Megaridis, Constantine; Walther, Jens; Koumoutsakos, Petros; Patankar, Neelesh

    2012-11-01

    Lotus leaves are known for their non-wetting properties due to the presence of surface texture. The superhydrophobic behavior arises because of the prevention of liquid water from entering the pores of the roughness. Present superhydrophobic materials rely on air trapped within the surface pores to avoid liquid permeation. This is typically unsustainable for immersed bodies due to dissolution of the air, especially under elevated pressures. Here, molecular dynamics simulations are used to demonstrate the non-wetting behavior of an immersed ten-nanometer pore. This is accomplished by establishing thermodynamically sustained vapor pockets of the surrounding liquid medium. Over 300,000 atoms were used to construct the nanopore geometry and simulate SPC/E water molecules. Ambient pressure was varied along two isotherms (300 K, and 500 K). This approach for vapor-stabilization could offer valuable guidance for maintaining surfaces dry even in a submerged state without relying on trapped air. The approach may be extended to control general phase behavior of water adjacent to textured surfaces. ISEN support is gratefully acknowledged.

  16. Dry wind tunnel system

    NASA Technical Reports Server (NTRS)

    Chen, Ping-Chih (Inventor)

    2013-01-01

    This invention is a ground flutter testing system without a wind tunnel, called Dry Wind Tunnel (DWT) System. The DWT system consists of a Ground Vibration Test (GVT) hardware system, a multiple input multiple output (MIMO) force controller software, and a real-time unsteady aerodynamic force generation software, that is developed from an aerodynamic reduced order model (ROM). The ground flutter test using the DWT System operates on a real structural model, therefore no scaled-down structural model, which is required by the conventional wind tunnel flutter test, is involved. Furthermore, the impact of the structural nonlinearities on the aeroelastic stability can be included automatically. Moreover, the aeroservoelastic characteristics of the aircraft can be easily measured by simply including the flight control system in-the-loop. In addition, the unsteady aerodynamics generated computationally is interference-free from the wind tunnel walls. Finally, the DWT System can be conveniently and inexpensively carried out as a post GVT test with the same hardware, only with some possible rearrangement of the shakers and the inclusion of additional sensors.

  17. Impacts of "wet seasons get wetter, dry seasons get drier"

    NASA Astrophysics Data System (ADS)

    Chou, C.; Lan, C.; Lee, C.; Chung, C.; Laio, Y.; Chiang, J. C.

    2012-12-01

    Global temperatures have increased for the past few decades. Changes to the global hydrological cycle have also been observed, but with a greater uncertainty and a strong spatial variation. The most robust change is that wet regions get wetter and dry regions get drier. Here we demonstrate that the tendency of wet-get-wetter and dry-get-drier occurs over the course of the seasonal cycle: wet seasons get wetter and dry seasons get drier, enhancing the annual precipitation range. Over 1979-2010, the globally-averaged changes in precipitation are 13.64±2.86%°C-1, -39.73±7.38%°C-1 and 33.03±6.42%°C-1 respectively for wet seasons, dry seasons, and the annual range. The trend magnitudes vary over a shorter evaluation period (1988-2010), but the sign of the tendencies remain the same. The magnitudes of these globally-averaged trends imply an inconclusive change in the strength of the corresponding tropical circulation. Regionally, the "wet seasons get wetter (dry seasons get drier)" tendency occurs over areas with greater (less) annual mean precipitation. The enhanced annual precipitation range may strongly impact local agriculture and water resources even in situations where the annual mean precipitation does not change significantly.

  18. Steam atmosphere drying concepts using steam exhaust recompression

    SciTech Connect

    DiBella, F.A.

    1992-08-01

    In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg{sub evap} to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

  19. Steam atmosphere drying concepts using steam exhaust recompression

    SciTech Connect

    DiBella, F.A. )

    1992-08-01

    In the US industrial drying accounts for approximately 1.5 quads of energy use per year. Annual industrial dryer expenditures are estimated to be in the $500 million range. Industrial drying is a significant energy and monetary expense. For the thermal drying processes in which water is removed via evaporation from the feedstock, attempts have been made to reduce the consumption of energy using exhaust waste heat recovery techniques, improved dryer designs, or even the deployment of advanced mechanical dewatering techniques. Despite these efforts, it is obvious that a large amount of thermal energy is often still lost if the latent heat of evaporation from the evaporated water cannot be recovered and/or in some way be utilized as direct heat input into the dryer. Tecogen Inc. is conducting research and development on an industrial drying concept. That utilizes a directly or indirectly superheated steam cycle atmosphere with exhaust steam recompression to recover the latent heat in the exhaust that would otherwise be lost. This approach has the potential to save 55 percent of the energy required by a conventional air dryer. Other advantages to the industrial dryer user include: A 35-percent reduction in the yearly cost per kg[sub evap] to dry wet feedstock, Reduced airborne emissions, Reduced dry dust fire/explosion risks, Hot product not exposed to oxygen thus, the product quality is enhanced, Constant rate drying in steam atmosphere, Reduced dryer size and cost, Reduced dryer heat losses due to lower dryer inlet temperatures. Tecogen has projected that the steam atmosphere drying system is most suitable as a replacement technology for state-of-the-art spray, flash, and fluidized bed drying systems. Such systems are utilized in the food and kindred products; rubber products; chemical and allied products; stone, clay, and glass; textiles; and pulp and paper industrial sectors.

  20. Ecohydrology and biogeochemistry of seasonally-dry ecosystems

    NASA Astrophysics Data System (ADS)

    Feng, X.; Porporato, A. M.

    2010-12-01

    The composition and the dynamic in various types of seasonally dry ecosystems are largely determined by rainfall seasonality and distribution. The intermittency of rainfall in these ecosystems has played a dominant role in the life cycle of native plants such that phenological events such as growth or reproduction have oftentimes become synchronized with the onset of the dry or the wet season. Characteristic amongst such types of ecosystems are the tropical dry and Mediterranean ecosystems, both of which receive similar amount of precipitation yet are markedly distinct in their synchronization of rainfall fluctuations and temperature. Seasonally dry ecosystems cover more than 16 million square kilometers in the tropics, with short but intense wet seasons followed by long dry seasons and elevated temperature throughout the year. Native vegetation grows during the wet season and adopts dormancy or seasonal deciduousness to cope with the dry season. In the Mediterranean climates, precipitations and temperature are out of phase, with wet temperate winters and hot dry summers. Dimorphic root systems are prevalent, where deep rooted plants exploit the winter recharge while the shallow rooted species take advantage of the infrequent summer rains. Using a stochastic soil moisture model we analyze how temporal shifts, or the lack thereof, in temperature and precipitation patterns affect the development of water stress during the dry season and its feedbacks on soil-plant biogeochemistry. We especially focus on the role of differences in temperature and seasonal potential evapotranspiration between tropical dry and Mediterranean climates. We also compare irrigation needs and the effects of projected climatic conditions in those regions. Understanding how plants adopt different water use strategies in the context of shifted climatic patterns will shed light on how these regions of high biodiversity may cope with rapidly-changing climatic conditions.

  1. Dry Ice Moves on Mars

    NASA Image and Video Library

    2013-06-11

    Serina Diniega, JPL Systems Engineer, describes the discovery that Martian gullies that end in pits rather than fan deltas are likely caused by block of frozen carbon dioxide (dry ice) sliding down slopes on a cushion of carbon dioxide gas. The pits are formed as the "dry ice" sublimates away.

  2. Dry root rot of chickpea

    USDA-ARS?s Scientific Manuscript database

    Dry root rot of chickpea is a serious disease under dry hot summer conditions, particularly in the semi-arid tropics of Ethiopia, and in central and southern India. It usually occurs at reproductive stages of the plant. Symptoms include drooping of petioles and leaflets of the tips, but not the low...

  3. Dry eye disease after LASIK

    PubMed Central

    Ţuru, L; Alexandrescu, C; Stana, D; Tudosescu, R

    2012-01-01

    LASIK is a surgical tehnique for the correction of refractive errors (myopia, hyperopia, astygmatism). It results in a reshape of the cornea with ocular surface and especially tear film disease. It is a cause for a iatrogenic dry eye syndrome. Neurogenic and inflamatory theory explain this disease. The main therapy of dry eye is the replacement with artificial tears. PMID:22574092

  4. Whey drying on porous carriers

    SciTech Connect

    Mitura, E.; Kaminski, W.

    1996-05-01

    Whey is treated very often as a waste which pollutes the natural environment. Whey which is a valuable source of protein, lacrose, vitamins and mineral salts should be utilized completely. The present paper is a proposal of whey drying on porous carriers. It is proved experimentally that the proposed drying method guarantees good product quality.

  5. Microwave Drying of Moist Coals

    NASA Astrophysics Data System (ADS)

    Salomatov, Vl. V.; Karelin, V. A.; Sladkov, S. O.; Salomatov, Vas. V.

    2017-03-01

    Physical principles and examples of practical implementation of drying large bodies of coal by microwave radiation are considered. It is shown that energy consumption in microwave drying of brown coals decreases to 1.5-1.8 (kW·h)/ kg as compared with traditional types of drying, for which the expenditures of energy amount to 3.0 (kW·h)/kg. In using microwave drying, the technological time of drying decreases to 4 h, whereas the time of convective drying, with other things being equal, comes to 8-20 h. Parallel with microwave radiation drying, grinding of a fuel takes place, as well as entrainment of such toxic and ecologically harmful elements as mercury, chlorine, phosphorus, sulfur, and nitrogen. An analysis of the prospects of using a microwave energy for drying coal fuel has shown that microwave radiation makes it possible to considerably economize in energy, increase explosional safety, improve the ecological situation, and reduce the metal content and overall dimensions of the equipment.

  6. High performance surface-emitting lasers with dry etched facets

    NASA Astrophysics Data System (ADS)

    Ou, S. S.; Jansen, M.; Yang, J. J.; Sergant, M.; Mawst, L. J.; Botez, D.; Roth, T. J.; Hess, C.; Tu, C.

    1992-12-01

    The fabrication, performance characteristics, and applications of monolithic in-plane surface-emitting lasers (IPSELs) with dry-etched 45-degree micromirrors are reviewed. Several types of such laser diode structures in both junction-up and junction-down configurations are considered. The performance goals for IPSELs with 45-degree micromirrors are high power and efficiency, high duty cycle and CW operation, good reliability, and high fabrication yields. The proposed approach for achieving these goals includes uniform quantum well material growth and dry etching of the laser micromirrors with tight fabrication tolerances.

  7. Hot, Dry and Cloudy

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Hot, Dry and Cloudy

    This artist's concept shows a cloudy Jupiter-like planet that orbits very close to its fiery hot star. NASA's Spitzer Space Telescope was recently used to capture spectra, or molecular fingerprints, of two 'hot Jupiter' worlds like the one depicted here. This is the first time a spectrum has ever been obtained for an exoplanet, or a planet beyond our solar system.

    The ground-breaking observations were made with Spitzer's spectrograph, which pries apart infrared light into its basic wavelengths, revealing the 'fingerprints' of molecules imprinted inside. Spitzer studied two planets, HD 209458b and HD 189733b, both of which were found, surprisingly, to have no water in the tops of their atmospheres. The results suggest that the hot planets are socked in with dry, high clouds, which are obscuring water that lies underneath. In addition, HD209458b showed hints of silicates, suggesting that the high clouds on that planet contain very fine sand-like particles.

    Capturing the spectra from the two hot-Jupiter planets was no easy feat. The planets cannot be distinguished from their stars and instead appear to telescopes as single blurs of light. One way to get around this is through what is known as the secondary eclipse technique. In this method, changes in the total light from a so-called transiting planet system are measured as a planet is eclipsed by its star, vanishing from our Earthly point of view. The dip in observed light can then be attributed to the planet alone.

    This technique, first used by Spitzer in 2005 to directly detect the light from an exoplanet, currently only works at infrared wavelengths, where the differences in brightness between the planet and star are less, and the planet's light is easier to pick out. For example, if the experiment had been done in visible light, the total light from the system would appear to be unchanged

  8. Hot, Dry and Cloudy

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Hot, Dry and Cloudy

    This artist's concept shows a cloudy Jupiter-like planet that orbits very close to its fiery hot star. NASA's Spitzer Space Telescope was recently used to capture spectra, or molecular fingerprints, of two 'hot Jupiter' worlds like the one depicted here. This is the first time a spectrum has ever been obtained for an exoplanet, or a planet beyond our solar system.

    The ground-breaking observations were made with Spitzer's spectrograph, which pries apart infrared light into its basic wavelengths, revealing the 'fingerprints' of molecules imprinted inside. Spitzer studied two planets, HD 209458b and HD 189733b, both of which were found, surprisingly, to have no water in the tops of their atmospheres. The results suggest that the hot planets are socked in with dry, high clouds, which are obscuring water that lies underneath. In addition, HD209458b showed hints of silicates, suggesting that the high clouds on that planet contain very fine sand-like particles.

    Capturing the spectra from the two hot-Jupiter planets was no easy feat. The planets cannot be distinguished from their stars and instead appear to telescopes as single blurs of light. One way to get around this is through what is known as the secondary eclipse technique. In this method, changes in the total light from a so-called transiting planet system are measured as a planet is eclipsed by its star, vanishing from our Earthly point of view. The dip in observed light can then be attributed to the planet alone.

    This technique, first used by Spitzer in 2005 to directly detect the light from an exoplanet, currently only works at infrared wavelengths, where the differences in brightness between the planet and star are less, and the planet's light is easier to pick out. For example, if the experiment had been done in visible light, the total light from the system would appear to be unchanged

  9. NiH2 Cycle Life Study

    NASA Technical Reports Server (NTRS)

    Hollandsworth, Roger P.; Armantrout, Jon D.; Rao, Gopalakrishna M.

    2002-01-01

    Cycle life studies have been performed at Eagle Picher Technologies (EPT), on HST Mantech design cells with various pedigrees of slurry and dry sinter processed electrodes, to evaluate peak load voltage performance during generic load profile testing. These tests provide information for determining voltage and capacity fade (degradation) mechanisms, and their impact on nickel hydrogen cell cycle life. Comparison of peak load voltage fade, as a function of State of Charge and cycle life, with capacity data from HST indicates that the cycle life limiting mechanism is due to impedance growth, and formation of a second discharge plateau. With a second plateau on discharge, capacity from the cell is still available, but at an unacceptable low voltage of 0.8 V per cell (17.6 V battery). Data shows that cell impedance increases with cycle number and depth of discharge, as expected.

  10. NiH2 Cycle Life Study

    NASA Technical Reports Server (NTRS)

    Hollandsworth, Roger P.; Armantrout, Jon D.; Rao, Gopalakrishna M.

    2002-01-01

    Cycle life studies have been performed at Eagle Picher Technologies (EPT), on HST Mantech design cells with various pedigrees of slurry and dry sinter processed electrodes, to evaluate peak load voltage performance during generic load profile testing. These tests provide information for determining voltage and capacity fade (degradation) mechanisms, and their impact on nickel hydrogen cell cycle life. Comparison of peak load voltage fade, as a function of State of Charge and cycle life, with capacity data from HST indicates that the cycle life limiting mechanism is due to impedance growth, and formation of a second discharge plateau. With a second plateau on discharge, capacity from the cell is still available, but at an unacceptable low voltage of 0.8 V per cell (17.6 V battery). Data shows that cell impedance increases with cycle number and depth of discharge, as expected.

  11. Space and Industrial Brine Drying Technologies

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.; Wisniewski, Richard S.; Flynn, Michael; Shaw, Hali

    2014-01-01

    This survey describes brine drying technologies that have been developed for use in space and industry. NASA has long considered developing a brine drying system for the International Space Station (ISS). Possible processes include conduction drying in many forms, spray drying, distillation, freezing and freeze drying, membrane filtration, and electrical processes. Commercial processes use similar technologies. Some proposed space systems combine several approaches. The current most promising candidates for use on the ISS use either conduction drying with membrane filtration or spray drying.

  12. Hydrological cycle.

    PubMed

    Gonçalves, H C; Mercante, M A; Santos, E T

    2011-04-01

    The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water.

  13. The nitrogen cycle: Atmosphere interactions

    NASA Technical Reports Server (NTRS)

    Levine, J. S.

    1984-01-01

    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  14. No Heat Spray Drying Technology

    SciTech Connect

    Beetz, Charles

    2016-06-15

    No Heat Spray Drying Technology. ZoomEssence has developed our Zooming™ spray drying technology that atomizes liquids to powders at ambient temperature. The process of drying a liquid into a powder form has been traditionally achieved by mixing a heated gas with an atomized (sprayed) fluid within a vessel (drying chamber) causing the solvent to evaporate. The predominant spray drying process in use today employs air heated up to 400° Fahrenheit to dry an atomized liquid into a powder. Exposing sensitive, volatile liquid ingredients to high temperature causes molecular degradation that negatively impacts solubility, stability and profile of the powder. In short, heat is detrimental to many liquid ingredients. The completed award focused on several areas in order to advance the prototype dryer to a commercial scale integrated pilot system. Prior to the award, ZoomEssence had developed a prototype ‘no-heat’ dryer that firmly established the feasibility of the Zooming™ process. The award focused on three primary areas to improve the technology: (1) improved ability to formulate emulsions for specific flavor groups and improved understanding of the relationship of emulsion properties to final dry particle properties, (2) a new production atomizer, and (3) a dryer controls system.

  15. Drying of thin colloidal films

    NASA Astrophysics Data System (ADS)

    Routh, Alexander F.

    2013-04-01

    When thin films of colloidal fluids are dried, a range of transitions are observed and the final film profile is found to depend on the processes that occur during the drying step. This article describes the drying process, initially concentrating on the various transitions. Particles are seen to initially consolidate at the edge of a drying droplet, the so-called coffee-ring effect. Flow is seen to be from the centre of the drop towards the edge and a front of close-packed particles passes horizontally across the film. Just behind the particle front the now solid film often displays cracks and finally the film is observed to de-wet. These various transitions are explained, with particular reference to the capillary pressure which forms in the solidified region of the film. The reasons for cracking in thin films is explored as well as various methods to minimize its effect. Methods to obtain stratified coatings through a single application are considered for a one-dimensional drying problem and this is then extended to two-dimensional films. Different evaporative models are described, including the physical reason for enhanced evaporation at the edge of droplets. The various scenarios when evaporation is found to be uniform across a drying film are then explained. Finally different experimental techniques for examining the drying step are mentioned and the article ends with suggested areas that warrant further study.

  16. High-intensity drying processes: Impulse drying. Annual report

    SciTech Connect

    Orloff, D.I.; Phelan, P.M.

    1993-12-01

    Experiments were conducted on a sheet-fed pilot-scale shoe press to compare impulse drying and double-felted pressing. Both an IPST (Institute of Paper Science and Technology) ceramic coated and Beloit Type A press roll were evaluated for lienrboard sheet structures having a wide range of z-direction permeability. Purpose was to find ways of correcting sheet sticking problems observed in previous pilot-scale shoe press experiments. Results showed that impulse drying was superior to double felted pressing in both press dryness and in important paper physical properties. Impulse drying critical temperature was found to depend on specific surface of the heated layer of the sheet, thermal properties of the press roll surface, and choice of felt. Impulse drying of recycled and two-ply liner was demonstrated for both Southern Pile and Douglas fir-containing furnishes.

  17. Aging and dry eye disease

    PubMed Central

    Ding, Juan; Sullivan, David A.

    2012-01-01

    Dry eye disease is a prevalent eye disorder that in particular affects the elderly population. One of the major causes of dry eye, meibomian gland dysfunction (MGD), shows increased prevalence with aging. MGD is caused by hyperkeratinization of the ductal epithelium of meibomian gland and reduced quantity and/or quality of meibum, the holocrine product that stabilizes and prevents the evaporation of the tear film. Of note, retinoids which are used in current anti-aging cosmetics may promote the development of MGD and dry eye disease. In this review, we will discuss the possible mechanisms of age-related MGD. PMID:22569356

  18. Spent fuel drying system test results (second dry-run)

    SciTech Connect

    Klinger, G.S.; Oliver, B.M.; Abrefah, J.; Marschman, S.C.; MacFarlan, P.J.; Ritter, G.A.

    1998-07-01

    The water-filled K-Basins in the Hanford 100 Area have been used to store N-Reactor spent nuclear fuel (SNF) since the 1970s. Because some leaks have been detected in the basins and some of the fuel is breached due to handling damage and corrosion, efforts are underway to remove the fuel elements from wet storage. An Integrated Process Strategy (IPS) has been developed to package, dry, transport, and store these metallic uranium fuel elements in an interim storage facility on the Hanford Site (WHC 1995). Information required to support the development of the drying processes, and the required safety analyses, is being obtained from characterization tests conducted on fuel elements removed from the K-Basins. A series of whole element drying tests (reported in separate documents, see Section 7.0) have been conducted by Pacific Northwest National Laboratory (PNNL) on several intact and damaged fuel elements recovered from both the K-East and K-West Basins. This report documents the results of the second dry-run test, which was conducted without a fuel element. With the concurrence of project management, the test protocol for this run, and subsequent drying test runs, was modified. These modifications were made to allow for improved data correlation with drying procedures proposed under the IPS. Details of these modifications are discussed in Section 3.0.

  19. The Contemporary Carbon Cycle

    NASA Astrophysics Data System (ADS)

    Houghton, R. A.

    2003-12-01

    The global carbon cycle refers to the exchanges of carbon within and between four major reservoirs: the atmosphere, the oceans, land, and fossil fuels. Carbon may be transferred from one reservoir to another in seconds (e.g., the fixation of atmospheric CO2 into sugar through photosynthesis) or over millennia (e.g., the accumulation of fossil carbon (coal, oil, gas) through deposition and diagenesis of organic matter). This chapter emphasizes the exchanges that are important over years to decades and includes those occurring over the scale of months to a few centuries. The focus will be on the years 1980-2000 but our considerations will broadly include the years ˜1850-2100. Chapter 8.09, deals with longer-term processes that involve rates of carbon exchange that are small on an annual timescale (weathering, vulcanism, sedimentation, and diagenesis).The carbon cycle is important for at least three reasons. First, carbon forms the structure of all life on the planet, making up ˜50% of the dry weight of living things. Second, the cycling of carbon approximates the flows of energy around the Earth, the metabolism of natural, human, and industrial systems. Plants transform radiant energy into chemical energy in the form of sugars, starches, and other forms of organic matter; this energy, whether in living organisms or dead organic matter, supports food chains in natural ecosystems as well as human ecosystems, not the least of which are industrial societies habituated (addicted?) to fossil forms of energy for heating, transportation, and generation of electricity. The increased use of fossil fuels has led to a third reason for interest in the carbon cycle. Carbon, in the form of carbon dioxide (CO2) and methane (CH4), forms two of the most important greenhouse gases. These gases contribute to a natural greenhouse effect that has kept the planet warm enough to evolve and support life (without the greenhouse effect the Earth's average temperature would be -33

  20. 2008 National dry mill corn ethanol survey.

    PubMed

    Mueller, Steffen

    2010-09-01

    Emerging regulations require an examination of corn ethanol's greenhouse gas emissions on a life cycle basis, including emissions from energy consumed at the plant level. However, comprehensive survey data of the industry's average performance dates back to 2001, prior to the industry's expansion phase. Responding to the need for updated data, we conducted a survey to collect energy and processing data for average dry mill ethanol produced during 2008. The study finds that the average liter of anhydrous corn ethanol produced during 2008 requires 28% less thermal energy than 2001 ethanol: 7.18 MJ/l compared to 10 MJ/l. Also, 2008 ethanol requires 32% less electricity: 0.195 kWh/l compared to 0.287 kWh/l, but anhydrous ethanol yields from corn are 5.3% higher and total 0.416 l/kg compared to 0.395 l/kg. Findings also suggest that older plants installed energy efficiency retrofits.

  1. Freeze-drying processes and wind erodibility of a clay loam soil in southern Alberta

    SciTech Connect

    Bullock, M S.; Larney, F. J.; McGinn, Sean M.; Izaurralde, R Cesar C.

    1999-01-01

    Freeze-drying has been implicated as a factor causing soil aggregate breakdown on the Canadian Prairies and northern Great Plains. Aggregates of a Dark Brown Chernozemic clay loam soil sampled in October 1993 and January and April 1994 were subjected to repeated cycles of wetting (to 0.1, 0.2 and 0.3 kg kg-1 water contents) freezing, and freeze-drying under laboratory conditions. The October 1993 samples showed less disruption when initially exposed to freeze-drying cycles compared to samples taken in January and April 1994. Using regression analysis, we predicted that 31 freeze-dry cycles were required for the 0.1 kg kg-1 water content aggregates to reach 60% erodible fraction (EF, % aggregates <0.86 mm), 9 cycles for the 0.2 kg kg-1 aggregates and 2 for 0.3 kg kg-1 aggregates. In a field study, conducted over the 1994-1995 winter on a similar clay loam soil, we estimated the number of freeze-drying cycles using large vapor pressure (VPL) and small vapor pressure (VPS) gradients bet ween the soil surface (which had a mean winter water content of {approx}0.1 kg kg-1) and the atmosphere. With solar energy adjustments, we predicted that the number of freeze-dry cycles required for the soil to reach 60% EF was 60 for VPL and 37 for VPS conditions. The latter number was similar to the 31 cycles predicted in the laboratory study of aggregates at 0.1 water content. Our results demonstrate that freeze-drying is an important overwinter process in the breakdown of soil aggregates and hence wind erosion risk in the Canadian prairie region.

  2. Accurate prediction of collapse temperature using optical coherence tomography-based freeze-drying microscopy.

    PubMed

    Greco, Kristyn; Mujat, Mircea; Galbally-Kinney, Kristin L; Hammer, Daniel X; Ferguson, R Daniel; Iftimia, Nicusor; Mulhall, Phillip; Sharma, Puneet; Kessler, William J; Pikal, Michael J

    2013-06-01

    The objective of this study was to assess the feasibility of developing and applying a laboratory tool that can provide three-dimensional product structural information during freeze-drying and which can accurately characterize the collapse temperature (Tc ) of pharmaceutical formulations designed for freeze-drying. A single-vial freeze dryer coupled with optical coherence tomography freeze-drying microscopy (OCT-FDM) was developed to investigate the structure and Tc of formulations in pharmaceutically relevant products containers (i.e., freeze-drying in vials). OCT-FDM was used to measure the Tc and eutectic melt of three formulations in freeze-drying vials. The Tc as measured by OCT-FDM was found to be predictive of freeze-drying with a batch of vials in a conventional laboratory freeze dryer. The freeze-drying cycles developed using OCT-FDM data, as compared with traditional light transmission freeze-drying microscopy (LT-FDM), resulted in a significant reduction in primary drying time, which could result in a substantial reduction of manufacturing costs while maintaining product quality. OCT-FDM provides quantitative data to justify freeze-drying at temperatures higher than the Tc measured by LT-FDM and provides a reliable upper limit to setting a product temperature in primary drying. Copyright © 2013 Wiley Periodicals, Inc.

  3. Sustaining dry surfaces under water

    PubMed Central

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-01-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments. PMID:26282732

  4. Sustaining dry surfaces under water.

    PubMed

    Jones, Paul R; Hao, Xiuqing; Cruz-Chu, Eduardo R; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M; Varanasi, Kripa K; Megaridis, Constantine M; Walther, Jens H; Koumoutsakos, Petros; Espinosa, Horacio D; Patankar, Neelesh A

    2015-08-18

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys - thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments.

  5. Sustaining dry surfaces under water

    NASA Astrophysics Data System (ADS)

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-08-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys - thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments.

  6. Dry eye disease: an immune-mediated ocular surface disorder

    PubMed Central

    Stevenson, William; Chauhan, Sunil K.; Dana, Reza

    2013-01-01

    Dry eye disease is a multifactorial disorder of the tears and ocular surface characterized by symptoms of dryness and irritation. Although the pathogenesis of dry eye disease is not fully understood, it is recognized that inflammation has a prominent role in the development and propagation of this debilitating condition. Factors that adversely affect tear film stability and osmolarity can induce ocular surface damage and initiate an inflammatory cascade that generates innate and adaptive immune responses. These immunoinflammatory responses lead to further ocular surface damage and the development of a self-perpetuating inflammatory cycle. Herein, we review the fundamental links between inflammation and dry eye disease and discuss the clinical implications of inflammation in disease management. PMID:22232476

  7. Myofascial trigger point therapy: laser therapy and dry needling.

    PubMed

    Uemoto, Luciana; Nascimento de Azevedo, Rosany; Almeida Alfaya, Thays; Nunes Jardim Reis, Renata; Depes de Gouvêa, Cresus Vinicius; Cavalcanti Garcia, Marco Antonio

    2013-09-01

    The aim of the present review is to discuss two forms of treatment for myofascial pain: laser therapy and dry needling. Although studies have reported the deactivation of myofascial trigger points with these two methods, clinical trials demonstrating their efficacy are scarce. The literature reports greater efficacy with the use of laser over dry needling. It has been suggested that improvements in microcirculation through the administration of laser therapy may favor the supply of oxygen to the cells under conditions of hypoxia and help remove the waste products of cell metabolism, thereby breaking the vicious cycle of pain, muscle spasm and further pain. While laser therapy is the method of choice for patients with a fear of needles and healthcare professionals inexperienced with the dry needling technique, further controlled studies are still needed to prove the greater efficacy of this method.

  8. Electrical Switchability and Dry-Wash Durability of Conductive Textiles

    PubMed Central

    Wu, Bangting; Zhang, Bowu; Wu, Jingxia; Wang, Ziqiang; Ma, Hongjuan; Yu, Ming; Li, Linfan; Li, Jingye

    2015-01-01

    There is growing interest in the area of conductive textiles in the scientific and industrial community. Herein, we successfully prepared a conductive textile via covalently grafting polyaniline (PANI) onto cotton by a multi-step treatment process. The conductivity of the resultant fabric could be tuned by immersing in water having different pH values. The conductive and insulating properties of the textile could be conveniently switched by alternately immersing in acidic and alkaline bath solutions. Most importantly, the resultant conductive fabrics were able to withstand 40 simulated dry-wash cycles, with almost no decay in the electrical conductivity, indicating their excellent dry-wash durability. The present strategy for fabricating conductive fabrics with excellent switchability of electrical properties and dry-wash durability is expected to provide inspiration for the production of multifunctional conductive textiles for use in hash or sensitive conditions. PMID:26066704

  9. Electrical Switchability and Dry-Wash Durability of Conductive Textiles

    NASA Astrophysics Data System (ADS)

    Wu, Bangting; Zhang, Bowu; Wu, Jingxia; Wang, Ziqiang; Ma, Hongjuan; Yu, Ming; Li, Linfan; Li, Jingye

    2015-06-01

    There is growing interest in the area of conductive textiles in the scientific and industrial community. Herein, we successfully prepared a conductive textile via covalently grafting polyaniline (PANI) onto cotton by a multi-step treatment process. The conductivity of the resultant fabric could be tuned by immersing in water having different pH values. The conductive and insulating properties of the textile could be conveniently switched by alternately immersing in acidic and alkaline bath solutions. Most importantly, the resultant conductive fabrics were able to withstand 40 simulated dry-wash cycles, with almost no decay in the electrical conductivity, indicating their excellent dry-wash durability. The present strategy for fabricating conductive fabrics with excellent switchability of electrical properties and dry-wash durability is expected to provide inspiration for the production of multifunctional conductive textiles for use in hash or sensitive conditions.

  10. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Thomas Nelson; Raghubir P. Gupta

    2005-01-01

    This report describes research conducted between October 1, 2004 and December 31, 2004 on the use of dry regenerable sorbents for removal of carbon dioxide from flue gas. Two supported sorbents were tested in a bench scale fluidized bed reactor system. The sorbents were prepared by impregnation of sodium carbonate on to an inert support at a commercial catalyst manufacturing facility. One sorbent, tested through five cycles of carbon dioxide sorption in an atmosphere of 3% water vapor and 0.8 to 3% carbon dioxide showed consistent reactivity with sodium carbonate utilization of 7 to 14%. A second, similarly prepared material, showed comparable reactivity in one cycle of testing. Batches of 5 other materials were prepared in laboratory scale quantities (primarily by spray drying). These materials generally have significantly greater surface areas than calcined sodium bicarbonate. Small scale testing showed no significant adsorption of mercury on representative carbon dioxide sorbent materials under expected flue gas conditions.

  11. Acid rain and dry deposition

    SciTech Connect

    Canter, L.W.

    1985-01-01

    This book provides information on the formation of acid rain and the long-range transport of air pollutants. The effects of acid precipitation on both terrestrial and aquatic ecosystems are highlighted and technical and policy issues associated with the delineation and implementation of control strategies for acid rain and dry deposition are covered. Dry deposition is addressed, with emphasis given to precipitation metals and organics.

  12. Drying in cyclones -- A review

    SciTech Connect

    Nebra, S.A.; Silva, M.A.; Mujumdar, A.S.

    2000-03-01

    This paper presents an overview of the flow, heat and mass transfer characteristics of vortex (or cyclone) dryers. The focus is on the potential of the cyclone configuration for drying of particulates. A selective review is made of the literature pertains to single phase and gas-particle flow in cyclone geometries. Recent data on drying of particulates in cyclone dryers are summarized. 56 refs.

  13. Dry PMR-15 Resin Powders

    NASA Technical Reports Server (NTRS)

    Vannucci, Raymond D.; Roberts, Gary D.

    1988-01-01

    Shelf lives of PMR-15 polymides lengthened. Procedure involves quenching of monomer reactions by vacuum drying of PRM-15 resin solutions at 70 to 90 degree F immediately after preparation of solutions. Absence of solvent eliminates formation of higher esters and reduces formation of imides to negligible level. Provides fully-formulated dry PMR-15 resin powder readily dissolvable in solvent at room temperature immediately before use. Resins used in variety of aerospace, aeronautical, and commercial applications.

  14. Morphology of drying blood pools

    NASA Astrophysics Data System (ADS)

    Laan, Nick; Smith, Fiona; Nicloux, Celine; Brutin, David; D-Blood project Collaboration

    2016-11-01

    Often blood pools are found on crime scenes providing information concerning the events and sequence of events that took place on the scene. However, there is a lack of knowledge concerning the drying dynamics of blood pools. This study focuses on the drying process of blood pools to determine what relevant information can be obtained for the forensic application. We recorded the drying process of blood pools with a camera and measured the weight. We found that the drying process can be separated into five different: coagulation, gelation, rim desiccation, centre desiccation, and final desiccation. Moreover, we found that the weight of the blood pool diminishes similarly and in a reproducible way for blood pools created in various conditions. In addition, we verify that the size of the blood pools is directly related to its volume and the wettability of the surface. Our study clearly shows that blood pools dry in a reproducible fashion. This preliminary work highlights the difficult task that represents blood pool analysis in forensic investigations, and how internal and external parameters influence its dynamics. We conclude that understanding the drying process dynamics would be advancement in timeline reconstitution of events. ANR funded project: D-Blood Project.

  15. Dry Eyes and Glaucoma: Double Trouble

    MedlinePlus

    ... News About Us Donate In This Section Dry Eyes and Glaucoma: Double Trouble email Send this article ... disease bothers the patient more. What Causes Dry Eye Syndrome? Dry eye can be caused by many ...

  16. The Kiln Drying of Wood for Airplanes

    NASA Technical Reports Server (NTRS)

    Tiemann, Harry D

    1919-01-01

    This report is descriptive of various methods used in the kiln drying of woods for airplanes and gives the results of physical tests on different types of woods after being dried by the various kiln-drying methods.

  17. Mucins in contact lens wear and dry eye conditions.

    PubMed

    Ramamoorthy, Padmapriya; Nichols, Jason J

    2008-08-01

    Ocular mucins are thought to play integral roles in ocular surface lubrication, anchoring of the aqueous, stabilizing the lipid components of the tear film, eliminating foreign bodies and pathogens, and with potential involvement in cell cycle mediation and apoptotic activity of ocular surface epithelia. Ocular mucins are of secreted and membrane-associated types. Secreted mucins may be of large gel-forming type or small soluble mucins (e.g., MUC5AC and MUC7). Membrane-associated mucins such as MUCs 1 and 4 are a major component of the glycocalyx. They are thought to render structural support to the microplicae and mediate epithelial cell cycle and apoptotic activity. The alterations in ocular mucins with contact lens wear are unclear. Recent work shows mucin expression may be up-regulated during the early years of contact lens wear, and with long-term lens wear, mucin expression may return to normal levels or sub-normal levels, although this is not well understood. Further, the polar nature of mucins may be associated with their affinity for contact lens surfaces making them a component of contact lens deposition. This has potential implications in the wettability and tolerability of contact lenses, and may be impacted by surface coatings, polymer characteristics, or care solutions. Conjunctival mucin gene expression and secretion may be deficient in several ocular surface disorders associated with dry eye. Deficiency and alterations in glycosylation characteristics of MUC5AC and MUC2 have been reported in both Sjögren and non-Sjögren dry eye types. Decreased binding of the membrane-associated mucin MUC16 to the conjunctival epithelium has been reported in Sjögren dry eye while MUC1 alterations have been reported in Sjögren and non-Sjögren dry eye states. In view of the mucin involvement in dry eye conditions, stimulation of mucus secretion pathways may hold promise in the pharmaceutical treatment of dry eye.

  18. CARBON DIOXIDE CAPTURE FROM FLUE GAS USING DRY REGENERABLE SORBENTS

    SciTech Connect

    David A. Green; Brian S. Turk; Jeffrey W. Portzer; Raghubir P. Gupta; William J. McMichael; Ya Liang; Tyler Moore; Douglas P. Harrison

    2003-08-01

    This report describes research conducted between April 1, 2003 and June 30, 2003 on the use of dry regenerable sorbents for concentration of carbon dioxide from flue gas. Grade 1 sodium bicarbonate performed similarly to grade 5 sodium bicarbonate in fixed bed testing in that activity improved after the first carbonation cycle and did not decline over the course of 5 cycles. Thermogravimetric analysis indicated that sodium bicarbonate sorbents produced by calcination of sodium bicarbonate are superior to either soda ash or calcined trona. Energy requirements for regeneration of carbon dioxide sorbents (either wet or dry) is of primary importance in establishing the economic feasibility of carbon dioxide capture processes. Recent studies of liquid amine sorption processes were reviewed and found to incorporate conflicting assumptions of energy requirements. Dry sodium based processes have the potential to be less energy intensive and thus less expensive than oxygen inhibited amine based systems. For dry supported sorbents, maximizing the active fraction of the sorbent is of primary importance in developing an economically feasible process.

  19. Fatigue limits of enamel bonds with moist and dry techniques.

    PubMed

    Barkmeier, Wayne W; Erickson, Robert L; Latta, Mark A

    2009-12-01

    Shear fatigue limit (SFL) testing, coupled with shear bond strength (SBS) measurements can provide valuable information regarding the ability of adhesive systems to bond to mineralized tooth structures. The clinical technique for enamel bonding with adhesive resins has shifted from bonding to a thoroughly dried acid conditioned surface to a moist surface to facilitate dentin bonding. The purpose of this study was to compare the performance of ethanol-containing etch-and-rinse adhesive (ERA) systems on moist and dry enamel by determining the resin composite to enamel SBS and SFL, and examining the relationship of SBS and SFL. Twelve specimens each were used to determine 24-h resin composite (Z100 - 3M ESPE) to enamel SBS to moist and dry surfaces with two ERA systems, Adper Single Bond Plus (SBP) and OptiBond Solo Plus (OBP). A staircase method of fatigue testing was used in a four-station fatigue cycler to determine the SFL of resin composite to enamel bonds (moist and dry) with the two ERA systems (20 specimens for each test condition) at 0.25Hz for 40,000 cycles. ANOVA and Tukey's post hoc test were used for the SBS data and a modified t-test with Bonferroni correction was used for comparisons of SFL. The two ERA systems each generated statistically similar SBS (p>0.05) to moist and dry enamel and the SBS of SBP was significantly higher than OBP on dry enamel (p<0.05). The SFL of SBP was significantly greater to dry enamel when compared to moist enamel and there was not a significant difference in the SFL of OBP on dry and moist enamel. There were no significant differences in SFL values between SBP on either moist or dry enamel and OBP on both moist and dry enamel. Fatigue testing may provide more useful information than SBS tests regarding the performance of dental adhesive systems. The chemical composition, solvents and filler components of ERA systems may influence their ability to develop long-term durable bonds to both moist and dry enamel surfaces.

  20. Larynx decellularization: combining freeze-drying and sonication as an effective method.

    PubMed

    Hung, Shih-Han; Su, Chin-Hui; Lee, Fei-Peng; Tseng, How

    2013-05-01

    Ideal methods for the reconstruction of the laryngeal structure and restoration of the laryngeal function once the larynx has been damaged or removed have not yet been developed. Thus, larynx tissue engineering practices have recently been extensively investigated. A scaffold may be generated using biocompatible or artificial materials. Decellularization methods, which use preexisting tissues as material sources, have also been used to manufacture larynx scaffolds with promising results. In this study, we developed a novel decellularization method that combines freezing, drying, and sonication. Porcine model study. Fresh porcine larynxes were used for decellularization. The process of the decellularization cycle comprised overnight freeze-drying, defreezing in phosphate-buffered saline (PBS) for 30 minutes, and washing in PBS for another 30 minutes. Sonication treatment was further added during the defreezing process. The decellularized tissue was then evaluated through histologic sections under hematoxylin and eosin staining. The results showed that a single use of the freeze-drying modality has little effect with regards to removing cellular components, even with increased decellularization cycles. However, when sonication was added to the defreezing process, the cellular contents were removed significantly (the residual nucleus ratios of freeze-drying:freeze-drying and defreezing one cycle:freeze-drying and defreezing three cycles:freeze-drying and defreezing under sonication three cycles were 91%:70%:47%:16%, respectively). However, the processed scaffold became structurally more fragile through the procedure. Combining freeze-drying and sonication during the defreezing process could be a promising method of decellularizing laryngeal tissues. However, this purely physical method may also induce structural damage to the scaffold. Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  1. Bipolar mood cycles and lunar tidal cycles.

    PubMed

    Wehr, T A

    2017-01-24

    In 17 patients with rapid cycling bipolar disorder, time-series analyses detected synchronies between mood cycles and three lunar cycles that modulate the amplitude of the moon's semi-diurnal gravimetric tides: the 14.8-day spring-neap cycle, the 13.7-day declination cycle and the 206-day cycle of perigee-syzygies ('supermoons'). The analyses also revealed shifts among 1:2, 1:3, 2:3 and other modes of coupling of mood cycles to the two bi-weekly lunar cycles. These shifts appear to be responses to the conflicting demands of the mood cycles' being entrained simultaneously to two different bi-weekly lunar cycles with slightly different periods. Measurements of circadian rhythms in body temperature suggest a biological mechanism through which transits of one of the moon's semi-diurnal gravimetric tides might have driven the patients' bipolar cycles, by periodically entraining the circadian pacemaker to its 24.84-h rhythm and altering the pacemaker's phase-relationship to sleep in a manner that is known to cause switches from depression to mania.Molecular Psychiatry advance online publication, 24 January 2017; doi:10.1038/mp.2016.263.

  2. Spent fuel drying system test results (first dry-run)

    SciTech Connect

    Klinger, G.S.; Oliver, B.M.; Abrefah, J.; Marschman, S.C.; MacFarlan, P.J.; Ritter, G.A.

    1998-07-01

    The water-filled K-Basins in the Hanford 100 Area have been used to store N-Reactor spent nuclear fuel (SNF) since the 1970s. Because some leaks in the basin have been detected and some of the fuel is breached due to handling damage and corrosion, efforts are underway to remove the fuel elements from wet storage. An Integrated Process Strategy (IPS) has been developed to package, dry, transport, and store these metallic uranium fuel elements in an interim storage facility on the Hanford Site. Information required to support the development of the drying processes, and the required safety analyses, is being obtained from characterization tests conducted on fuel elements removed from the K-Basins. A series of whole element drying tests (reported in separate documents, see Section 7.0) have been conducted by Pacific Northwest National Laboratory (PNNL) on several intact and damaged fuel elements recovered from both the K-East and K-West Basins. This report documents the results of the first dry-run test, which was conducted without a fuel element. The empty test apparatus was subjected to a combination of low- and high-temperature vacuum drying treatments that were intended to mimic, wherever possible, the fuel treatment strategies of the IPS. The data from this dry-run test can serve as a baseline for the first two fuel element tests, 1990 (Run 1) and 3128W (Run 2). The purpose of this dry-run was to establish the background levels of hydrogen in the system, and the hydrogen generation and release characteristics attributable to the test system without a fuel element present. This test also serves to establish the background levels of water in the system and the water release characteristics. The system used for the drying test series was the Whole Element Furnace Testing System, described in Section 2.0, which is located in the Postirradiation Testing Laboratory (PTL, 327 Building). The test conditions and methodology are given in section 3.0, and the experimental

  3. Quantification of perchloroethylene residues in dry-cleaned fabrics.

    PubMed

    Sherlach, Katy S; Gorka, Alexander P; Dantzler, Alexa; Roepe, Paul D

    2011-11-01

    We have used a novel gas chromatography/mass spectrometry (GC/MS)-based approach to quantify perchloroethylene (PCE) residues in dry-cleaned fabrics. Residual PCE was extracted from fabric samples with methanol and concentration was calculated by the gas chromatographic peak area, standardized using PCE calibration data. Extracts examined were from samples of 100% wool, polyester, cotton, or silk, which were dry cleaned from one to six times in seven different Northern Virginia dry-cleaning establishments. Additional experiments were conducted to investigate the kinetics of PCE release in the extraction solvent and to the open air. We found that polyester, cotton, and wool retained ≥ µM levels of PCE, that these levels increased in successive dry-cleaning cycles, and that PCE is slowly volatilized from these fabrics under ambient room air conditions. We found that silk does not retain appreciable PCE. Measured differences across dry-cleaning establishments and fabric type suggest more vigorous monitoring of PCE residues may be warranted. Environ. Toxicol. Chem. 2011;30:2481-2487. © 2011 SETAC.

  4. Potential evapotranspiration and continental drying

    USGS Publications Warehouse

    Milly, Paul C.D.; Dunne, Krista A.

    2016-01-01

    By various measures (drought area and intensity, climatic aridity index, and climatic water deficits), some observational analyses have suggested that much of the Earth’s land has been drying during recent decades, but such drying seems inconsistent with observations of dryland greening and decreasing pan evaporation. ‘Offline’ analyses of climate-model outputs from anthropogenic climate change (ACC) experiments portend continuation of putative drying through the twenty-first century, despite an expected increase in global land precipitation. A ubiquitous increase in estimates of potential evapotranspiration (PET), driven by atmospheric warming, underlies the drying trends, but may be a methodological artefact. Here we show that the PET estimator commonly used (the Penman–Monteith PET for either an open-water surface or a reference crop) severely overpredicts the changes in non-water-stressed evapotranspiration computed in the climate models themselves in ACC experiments. This overprediction is partially due to neglect of stomatal conductance reductions commonly induced by increasing atmospheric CO2 concentrations in climate models. Our findings imply that historical and future tendencies towards continental drying, as characterized by offline-computed runoff, as well as other PET-dependent metrics, may be considerably weaker and less extensive than previously thought.

  5. Potential evapotranspiration and continental drying

    NASA Astrophysics Data System (ADS)

    Milly, P. C. D.; Dunne, K. A.

    2016-10-01

    By various measures (drought area and intensity, climatic aridity index, and climatic water deficits), some observational analyses have suggested that much of the Earth’s land has been drying during recent decades, but such drying seems inconsistent with observations of dryland greening and decreasing pan evaporation. `Offline’ analyses of climate-model outputs from anthropogenic climate change (ACC) experiments portend continuation of putative drying through the twenty-first century, despite an expected increase in global land precipitation. A ubiquitous increase in estimates of potential evapotranspiration (PET), driven by atmospheric warming, underlies the drying trends, but may be a methodological artefact. Here we show that the PET estimator commonly used (the Penman-Monteith PET for either an open-water surface or a reference crop) severely overpredicts the changes in non-water-stressed evapotranspiration computed in the climate models themselves in ACC experiments. This overprediction is partially due to neglect of stomatal conductance reductions commonly induced by increasing atmospheric CO2 concentrations in climate models. Our findings imply that historical and future tendencies towards continental drying, as characterized by offline-computed runoff, as well as other PET-dependent metrics, may be considerably weaker and less extensive than previously thought.

  6. Bipolar Mood Cycles and Lunar Tidal Cycles

    PubMed Central

    Wehr, Thomas A.

    2016-01-01

    In seventeen patients with rapid cycling bipolar disorder, time-series analyses detected synchronies between mood cycles and three lunar cycles that modulate the amplitude of the moon’s semi-diurnal gravimetric tides: the 14.8-day spring-neap cycle, the 13.7-day declination cycle, and the 206-day cycle of perigee-syzygies (“supermoons”). The analyses also revealed shifts among 1:2, 1:3, 2:3 and other modes of coupling of mood cycles to the two bi-weekly lunar cycles. These shifts appear to be responses to the conflicting demands of the mood cycles’ being entrained simultaneously to two different bi-weekly lunar cycles with slightly different periods. Measurements of circadian rhythms in body temperature suggest a biological mechanism through which transits of one of the moon’s semi-diurnal gravimetric tides might have driven the patients’ bipolar cycles, by periodically entraining the circadian pacemaker to its 24.84-hour rhythm and altering the pacemaker’s phase-relationship to sleep in a manner that is known to cause switches from depression to mania. PMID:28115741

  7. Fragmentation of drying paint layers

    NASA Astrophysics Data System (ADS)

    Bakos, Katinka; Dombi, András; Járai-Szabó, Ferenc; Néda, Zoltán

    2013-11-01

    Fragmentation of thin layers of drying granular materials on a frictional surface are studied both by experiments and computer simulations. Besides a qualitative description of the fragmentation phenomenon, the dependence of the average fragment size as a function of the layer thickness is thoroughly investigated. Experiments are done using a special nail polish, which forms characteristic crack structures during drying. In order to control the layer thickness, we diluted the nail polish in acetone and evaporated in a controlled manner different volumes of this solution on glass surfaces. During the evaporation process we managed to get an instable paint layer, which formed cracks as it dried out. In order to understand the obtained structures a previously developed spring-block model was implemented in a three-dimensional version. The experimental and simulation results proved to be in excellent qualitative and quantitative agreement. An earlier suggested scaling relation between the average fragment size and the layer thickness is reconfirmed.

  8. Solar Drying of Red Mud

    NASA Astrophysics Data System (ADS)

    Chandler, John L.

    Solar drying of thickened red mud is the latest method for its disposal in an economical and environmentally acceptable way. Two years full scale experience with this method in Jamaica has shown that its success depends on accurate grading of the solar drying area and accurate control of the pre-dewatering of the mud in the alumina plant. Experience with the use of deep thickening for pre-dewatering is described, together with a novel method for measurement and control of thickened mud rheology.

  9. Fundamentals of freeze-drying.

    PubMed

    Nail, Steven L; Jiang, Shan; Chongprasert, Suchart; Knopp, Shawn A

    2002-01-01

    Given the increasing importance of reducing development time for new pharmaceutical products, formulation and process development scientists must continually look for ways to "work smarter, not harder." Within the product development arena, this means reducing the amount of trial and error empiricism in arriving at a formulation and identification of processing conditions which will result in a quality final dosage form. Characterization of the freezing behavior of the intended formulation is necessary for developing processing conditions which will result in the shortest drying time while maintaining all critical quality attributes of the freeze-dried product. Analysis of frozen systems was discussed in detail, particularly with respect to the glass transition as the physical event underlying collapse during freeze-drying, eutectic mixture formation, and crystallization events upon warming of frozen systems. Experiments to determine how freezing and freeze-drying behavior is affected by changes in the composition of the formulation are often useful in establishing the "robustness" of a formulation. It is not uncommon for seemingly subtle changes in composition of the formulation, such as a change in formulation pH, buffer salt, drug concentration, or an additional excipient, to result in striking differences in freezing and freeze-drying behavior. With regard to selecting a formulation, it is wise to keep the formulation as simple as possible. If a buffer is needed, a minimum concentration should be used. The same principle applies to added salts: If used at all, the concentration should be kept to a minimum. For many proteins a combination of an amorphous excipient, such as a disaccharide, and a crystallizing excipient, such as glycine, will result in a suitable combination of chemical stability and physical stability of the freeze-dried solid. Concepts of heat and mass transfer are valuable in rational design of processing conditions. Heat transfer by conduction

  10. Development of freeze dried vegetables

    NASA Technical Reports Server (NTRS)

    Larson, R. W.

    1970-01-01

    The development of freeze dried vegetables to be used in the Apollo food system is discussed. After the initial selection and screening of vegetables, several types of freeze dried vegetables were prepared in small batches. From these small batches, two vegetables were judged satisfactory for further testing and evaluation. These vegetables, mashed potatoes and asparagus, were subjected to storage at 100 deg plus or minus 5 F. for two weeks and then taste tested. The vegetables were also tested to determine if they complied with the microbiological requirements for Apollo food. The space food prototype production guide for the vegetables is submitted.

  11. Drying leather with vacuum and toggling sequentially

    USDA-ARS?s Scientific Manuscript database

    We investigated a drying method that will enable leather to be dried under vacuum and stretch sequentially to improve area yield. Vacuum drying offers fast speed at a low temperature, which would be advantageous to heat-vulnerable chrome-free leather. Adding a toggle action after vacuum drying cou...

  12. Foam-mat Drying Technology: A Review.

    PubMed

    Hardy, Z; Jideani, V A

    2015-07-13

    This article reviews various aspects of foam-mat drying such as foam-mat drying processing technique, main additives used for foam-mat drying, foam-mat drying of liquid and solid foods, quality characteristics of foam-mat dried foods and economic and technical benefits for employing foam-mat drying. Foam-mat drying process is an alternative method which allows the removal of water from liquid materials and pureed materials. In this drying process, a liquid material is converted into foam that is stable by being whipped after adding an edible foaming agent. The stable foam is then spread out in sheet or mat and dried by using hot air (40 -90°C) at atmospheric pressure. Methyl cellulose (0.25 - 2%), egg white (3 - 20%), maltodextrin (0.5 - 05%) and gum Arabic (2 - 9%) are the commonly utilised additives for the foam-mat drying process at the given range, either combined together for their effectiveness or individual effect. The foam-mat drying process is suitable for heat sensitive, viscous and sticky products which cannot be dried using other forms of drying methods such as spray drying because of the state of product. More interest has developed for foam-mat drying because of the simplicity, cost effectiveness, high speed drying and improved product quality it provides.

  13. 7 CFR 58.813 - Dry whey.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Dry whey. 58.813 Section 58.813 Agriculture... Products Bearing Usda Official Identification § 58.813 Dry whey. The quality requirements for dry whey shall be in accordance with the U.S. Standards for Dry Whey. Supplemental Specifications for...

  14. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  15. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  16. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  17. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  18. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Dried yeasts. 172.896 Section 172.896 Food and... PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida...

  19. Is Blood Lactate Removal During Water Immersed Cycling Faster than During Cycling on Land?

    PubMed Central

    Masi, Fabrízio Di; De Souza Vale, Rodrigo Gomes; Dantas, Estélio Henrique Martin; Barreto, Ana Cristina Lopes; Novaes, Jefferson da Silva; Reis, Victor M.

    2007-01-01

    The aim of the present study was to compare lactate removal during active recovery performed during cycling in water immersion (CW) and during cycling on land (CL), after a similar exercise bout in male adults. Eleven healthy and physically active men, aged between 20 and 26 years old participated in the experiment. Before the experimental tests, the ventilatory threshold of the subjects was determined. Each subject completed the experimental tests twice, with one week separating the two periods of experiment. The subjects exercised on the treadmill during 6 min at a speed 10% above the speed corresponding to their ventilatory threshold. Subsequently, the subjects recovered from the exercise bout either on a stationary bike (CL) or on a aquatic-specific bike (CW). On the subsequent week the subjects performed the same protocol but with a different recovery condition. Recovery condition assignment for the first test was counterbalanced (six subjects started with one condition and five with the other). Capillary blood samples were collected after each test and during the recovery period (at 3, 6, 9 and 15 minutes) and blood lactate was measured. The blood lactate values during CW were lower than during CL and significant differences were observed at the 6th minute (p ≤ 0.05) and at the 15th minute of recovery (p ≤ 0.05). Therefore, we may conclude that active recovery using cycling in water immersion may be more efficient than cycling on land for blood lactate removal. Key pointsPrevious studies have found positive effects of half liquid environment on blood lactate removal.However, few studies have compared lactate removal in half liquid and in dry land conditions with the use of stationary bikes.We have compared the lactate removal during active recovery on half-liquid cycling and active recovery on dry land cycling after a similar exercise bout in male adults.The blood lactate values during the recovery were lower after half-liquid cycling when compared with

  20. Dry machinability of aluminum alloys.

    SciTech Connect

    Shareef, I.; Natarajan, M.; Ajayi, O. O.; Energy Technology; Department of IMET

    2005-01-01

    Adverse effects of the use of cutting fluids and environmental concerns with regard to cutting fluid disposability is compelling industry to adopt Dry or near Dry Machining, with the aim of eliminating or significantly reducing the use of metal working fluids. Pending EPA regulations on metal cutting, dry machining is becoming a hot topic of research and investigation both in industry and federal research labs. Although the need for dry machining may be apparent, most of the manufacturers still consider dry machining to be impractical and even if possible, very expensive. This perception is mainly due to lack of appropriate cutting tools that can withstand intense heat and Built-up-Edge (BUE) formation during dry machining. The challenge of heat dissipation without coolant requires a completely different approach to tooling. Special tooling utilizing high-performance multi-layer, multi-component, heat resisting, low friction coatings could be a plausible answer to the challenge of dry machining. In pursuit of this goal Argonne National Labs has introduced Nano-crystalline near frictionless carbon (NFC) diamond like coatings (DLC), while industrial efforts have led to the introduction of composite coatings such as titanium aluminum nitride (TiAlN), tungsten carbide/carbon (WC/C) and others. Although, these coatings are considered to be very promising, they have not been tested either from tribological or from dry machining applications point of view. As such a research program in partnership with federal labs and industrial sponsors has started with the goal of exploring the feasibility of dry machining using the newly developed coatings such as Near Frictionless Carbon Coatings (NFC), Titanium Aluminum Nitride (TiAlN), and multi-layer multicomponent nano coatings such as TiAlCrYN and TiAlN/YN. Although various coatings are under investigation as part of the overall dry machinability program, this extended abstract deals with a systematic investigation of dry

  1. Phase transitions in freeze-dried systems - quantification using in situ synchrotron X-ray diffractometry

    SciTech Connect

    Varshney, Dushyant B.; Sundaramurthi, Prakash; Kumar, Satyendra; Shalaev, Evgenyi Y.; Kang, Shin-Woong; Gatlin, Larry A.; Suryanarayanan, Raj

    2009-09-02

    The purpose is: (1) To develop a synchrotron X-ray diffraction (SXRD) method to monitor phase transitions during the entire freeze-drying cycle. Aqueous sodium phosphate buffered glycine solutions with initial glycine to buffer molar ratios of 1:3 (17:50 mM), 1:1 (50 mM) and 3:1 were utilized as model systems. (2) To investigate the effect of initial solute concentration on the crystallization of glycine and phosphate buffer salt during lyophilization. Phosphate buffered glycine solutions were placed in a custom-designed sample cell for freeze-drying. The sample cell, covered with a stainless steel dome with a beryllium window, was placed on a stage capable of controlled cooling and vacuum drying. The samples were cooled to -50 C and annealed at -20 C. They underwent primary drying at -25 C under vacuum until ice sublimation was complete and secondary drying from 0 to 25 C. At different stages of the freeze-drying cycle, the samples were periodically exposed to synchrotron X-ray radiation. An image plate detector was used to obtain time-resolved two-dimensional SXRD patterns. The ice, {beta}-glycine and DHPD phases were identified based on their unique X-ray peaks. When the solutions were cooled and annealed, ice formation was followed by crystallization of disodium hydrogen phosphate dodecahydrate (DHPD). In the primary drying stage, a significant increase in DHPD crystallization followed by incomplete dehydration to amorphous disodium hydrogen phosphate was evident. Complete dehydration of DHPD occurred during secondary drying. Glycine crystallization was inhibited throughout freeze-drying when the initial buffer concentration (1:3 glycine to buffer) was higher than that of glycine. A high-intensity X-ray diffraction method was developed to monitor the phase transitions during the entire freeze-drying cycle. The high sensitivity of SXRD allowed us to monitor all the crystalline phases simultaneously. While DHPD crystallizes in frozen solution, it dehydrates

  2. The Solar Cycle

    NASA Astrophysics Data System (ADS)

    Hathaway, David H.

    2015-12-01

    The solar cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. A number of other solar activity indicators also vary in association with the sunspots including; the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores. Individual solar cycles are characterized by their maxima and minima, cycle periods and amplitudes, cycle shape, the equatorward drift of the active latitudes, hemispheric asymmetries, and active longitudes. Cycle-to-cycle variability includes the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev-Ohl (even-odd) Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double-peaked maxima. We conclude with an examination of prediction techniques for the solar cycle and a closer look at cycles 23 and 24.

  3. Bioactive maca (Lepidium meyenii) alkamides are a result of traditional Andean postharvest drying practices.

    PubMed

    Esparza, Eliana; Hadzich, Antonella; Kofer, Waltraud; Mithöfer, Axel; Cosio, Eric G

    2015-08-01

    Maca, Lepidium meyenii Walpers (Brassicaceae), is an annual herbaceous plant native to the high plateaus of the Peruvian central Andes. Its underground storage hypocotyls have been a traditional medicinal agent and dietary staple since pre-Columbian times. Reported properties include energizing and fertility-enhancing effects. Published reports have focused on the benzylalkamides (macamides) present in dry hypocotyls as one of the main bioactive components. Macamides are secondary amides formed by benzylamine and a fatty acid moiety, with varying hydrocarbon chain lengths and degree of unsaturation. Although it has been assumed that they are usually present in fresh undamaged tissues, analyses show them to be essentially absent from them. However, hypocotyls dried by traditional Andean postharvest practices or industrial oven drying contain up to 800μgg(-1) dry wt (2.3μmolg(-1) dry wt) of macamides. In this study, the generation of macamides and their putative precursors were studied during nine-week traditional drying trials at 4200m altitude and in ovens under laboratory conditions. Freeze-thaw cycles in the open field during drying result in tissue maceration and release of free fatty acids from storage and membrane lipids up to levels of 1200μgg(-1) dry wt (4.3μmolg(-1) dry wt). Endogenous metabolism of the isothiocyanates generated from glucosinolate hydrolysis during drying results in maximal benzylamine values of 4300μgg(-1) dry wt (40.2μmolg(-1) dry wt). Pearson correlation coefficients of the accumulation profiles of benzylamine and free fatty acid to that of macamides showed good values of 0.898 and 0.934, respectively, suggesting that both provide sufficient substrate for amide synthesis during the drying process.

  4. USE OF COAL DRYING TO REDUCE WATER CONSUMED IN PULVERIZED COAL POWER PLANTS

    SciTech Connect

    Edward K. Levy; Nenad Sarunac; Wei Zhang

    2004-07-01

    This is the sixth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture, prior to firing in a pulverized coal boiler. Coal drying experiments were performed with a Powder River Basin coal to measure the effects of fluidization velocity and drying temperature on rate of drying in a batch drying process. Comparisons to computational results using the batch bed drying model show good agreement. Comparisons to drying results with North Dakota lignite at the same process conditions confirm the lignite dries slightly more rapidly than the PRB. Experiments were also carried out to determine the effects of inlet air humidity on drying rate. The specific humidity ranged from a value typical for air at temperatures near freezing to a value for 30 C air at 90 percent relative humidity. The experimental results show drying rate is strongly affected by inlet air humidity, with the rate decreasing with more humid inlet air. The temperature of the drying process also plays a strong role, with the negative impacts of high inlet moisture being less of a factor in a higher temperature drying process. Concepts for coal drying systems integrated into a power plant were developed. These make use of hot circulating cooling water from the condenser, steam extraction from the turbine cycle and thermal energy extracted from hot flue gas, in various combinations. Analyses are under way to calculate the effects of drying system design and process conditions on unit performance, emissions, and cooling tower makeup water.

  5. Dry bin filler for apples

    USDA-ARS?s Scientific Manuscript database

    A unique dry bin filler for apples using a sequenced tray was developed to reduce bruising in packing operations. Research and commercial trials in West Virginia, Pennsylvania, and Washington State demonstrated the ability to fill bins evenly and with low damage. Cultivars with different bruising su...

  6. THE DIRT ON DRY MERGERS

    SciTech Connect

    Desai, Vandana; Soifer, B. T.; Dey, Arjun; Cohen, Emma; Le Floc'h, Emeric

    2011-04-01

    Using data from the Spitzer Space Telescope, we analyze the mid-infrared (3-70 {mu}m) spectral energy distributions of dry merger candidates in the Booetes field of the NOAO Deep Wide-Field Survey. These candidates were selected by previous authors to be luminous, red, early-type galaxies with morphological evidence of recent tidal interactions. We find that a significant fraction of these candidates exhibit 8 and 24 {mu}m excesses compared to expectations for old stellar populations. We estimate that a quarter of dry merger candidates have mid-infrared-derived star formation rates greater than {approx}1 M{sub sun} yr{sup -1}. This represents a 'frosting' on top of a large old stellar population, and has been seen in previous studies of elliptical galaxies. Further, the dry merger candidates include a higher fraction of star-forming galaxies relative to a control sample without tidal features. We therefore conclude that the star formation in these massive ellipticals is likely triggered by merger activity. Our data suggest that the mergers responsible for the observed tidal features were not completely dry, and may be minor mergers involving a gas-rich dwarf galaxy.

  7. Drying Milk With Boiler Exhaust

    NASA Technical Reports Server (NTRS)

    Broussard, M. R.

    1984-01-01

    Considerable energy saved in powdered-milk industry. Only special requirement boiler fired with natural gas or other clean fuel. Boiler flue gas fed to spray drier where it directly contacts product to be dried. Additional heat supplied by auxillary combustor when boiler output is low. Approach adaptable to existing plants with minimal investment because most already equipped with natural-gas-fired boilers.

  8. Microwave drying of seed cotton

    USDA-ARS?s Scientific Manuscript database

    A small lab dryer was designed for use in drying seed cotton with components of a microwave generator mounted thereon. The magnetron emitted radiation directly into the seed cotton and a fan directed air cross-flow to the radiation direction. The microwave components were a 1.1 kW magnetron, trans...

  9. Granular flow: Dry and wet

    NASA Astrophysics Data System (ADS)

    Mitarai, N.; Nakanishi, H.

    2012-04-01

    Granular material is a collection of macroscopic particles that are visible with naked eyes. The non-equilibrium nature of the granular materials makes their rheology quite different from that of molecular systems. In this minireview, we present the unique features of granular materials focusing on the shear flow of dry granular materials and granule-liquid mixture.

  10. A new dry biomedical electrode

    NASA Technical Reports Server (NTRS)

    Luce, R. S.; Cleveland, G. J.

    1973-01-01

    Electronic circuitry contains new operational amplifier which incorporates monolithic super-gain transistors. Electrode does not provide voltage amplification; instead, it acts as current amplifier to make it possible to pick up electrical potentials from surface of highly resistant dry skin.

  11. Dry Zones Around Frozen Droplets

    NASA Astrophysics Data System (ADS)

    Bisbano, Caitlin; Nath, Saurabh; Boreyko, Jonathan; Nature-Inspired Fluids; Interfaces Team

    2015-11-01

    The saturation pressure of water vapor above supercooled water exceeds that above ice at the same temperature. A frozen droplet will therefore grow by harvesting water vapor from neighboring supercooled condensate, which has recently been demonstrated to be a primary mechanism of in-plane frost growth on hydrophobic surfaces. The underlying physics of this source-sink interaction is still poorly understood. In this work, a deposited water droplet is frozen on a dry hydrophobic surface initially held above the dew point. We demonstrate that when the surface is then cooled beneath the dew point, the frozen droplet harvests nearby water vapor in the air. This results in an annular dry zone that forms between the frozen droplet and the forming supercooled condensation. For a given ambient temperature and humidity, the length of the dry zone varied strongly with surface temperature and weakly with droplet volume. The dependence of the dry zone on surface temperature is due to the fact that the vapor pressure gradients between the ambient and the surface and between the liquid and frozen water are both functions of temperature.

  12. Drying Milk With Boiler Exhaust

    NASA Technical Reports Server (NTRS)

    Broussard, M. R.

    1984-01-01

    Considerable energy saved in powdered-milk industry. Only special requirement boiler fired with natural gas or other clean fuel. Boiler flue gas fed to spray drier where it directly contacts product to be dried. Additional heat supplied by auxillary combustor when boiler output is low. Approach adaptable to existing plants with minimal investment because most already equipped with natural-gas-fired boilers.

  13. Longevity Of Dry Film Lubricants

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Stockwell, R. D.

    1993-01-01

    Report describes evaluation of dry film lubricants candidate for use in rotary joints of proposed Space Station. Study included experiments and theoretical analyses focused on longevity of sputtered molybdenum disulfide films and ion-plated lead films under conditions partially simulating rolling contact.

  14. The Dirt on Dry Mergers

    NASA Astrophysics Data System (ADS)

    Desai, Vandana; Dey, Arjun; Cohen, Emma; Le Floc'h, Emeric; Soifer, B. T.

    2011-04-01

    Using data from the Spitzer Space Telescope, we analyze the mid-infrared (3-70 μm) spectral energy distributions of dry merger candidates in the Boötes field of the NOAO Deep Wide-Field Survey. These candidates were selected by previous authors to be luminous, red, early-type galaxies with morphological evidence of recent tidal interactions. We find that a significant fraction of these candidates exhibit 8 and 24 μm excesses compared to expectations for old stellar populations. We estimate that a quarter of dry merger candidates have mid-infrared-derived star formation rates greater than ~1 M sun yr-1. This represents a "frosting" on top of a large old stellar population, and has been seen in previous studies of elliptical galaxies. Further, the dry merger candidates include a higher fraction of star-forming galaxies relative to a control sample without tidal features. We therefore conclude that the star formation in these massive ellipticals is likely triggered by merger activity. Our data suggest that the mergers responsible for the observed tidal features were not completely dry, and may be minor mergers involving a gas-rich dwarf galaxy.

  15. Drying rate and temperature profile for superheated steam vacuum drying and moist air drying of softwood lumber

    SciTech Connect

    Pang, S.; Dakin, M.

    1999-07-01

    Two charges of green radiata pine sapwood lumber were dried, ether using superheated steam under vacuum (90 C, 0.2 bar abs.) or conventionally using hot moist air (90/60 C). Due to low density of the drying medium under vacuum, the circulation velocity used was 10 m/s for superheated steam drying and 5.0 m/s for moist air drying, and in both cases, the flow was unidirectional. In drying, stack drying rate and wood temperatures were measured to examine the differences between the superheated steam drying and drying using hot moist air. The experimental results have shown that the stack edge board in superheated steam drying dried faster than in the hot moist air drying. Once again due to the low density of the steam under vacuum, a prolonged maximum temperature drop across load (TDAL) was observed in the superheated steam drying, however, the whole stack dried slower and the final moisture content distribution was more variable than for conventional hot moist air drying.

  16. Effects of heat exposure in the absence of hyperthermia on power output during repeated cycling sprints

    PubMed Central

    Arimitsu, T; Yunoki, T; Kimura, T; Yamanaka, R; Yano, T

    2014-01-01

    The aim of this study was to investigate the effects of heat exposure in the absence of hyperthermia on power output during repeated cycling sprints. Seven males performed four 10-s cycling sprints interspersed by 30 s of active recovery on a cycle ergometer in hot-dry and thermoneutral environments. Changes in rectal temperature were similar under the two ambient conditions. The mean 2-s power output over the 1st–4th sprints was significantly lower under the hot-dry condition than under the thermoneutral condition. The amplitude of the electromyogram was lower under the hot-dry condition than under the thermoneutral condition during the early phase (0–3 s) of each cycling sprint. No significant difference was observed for blood lactate concentration between the two ambient conditions. Power output at the onset of a cycling sprint during repeated cycling sprints is decreased due to heat exposure in the absence of hyperthermia. PMID:25729145

  17. Use of gas turbine exhaust for the direct drying of food products: Final report

    SciTech Connect

    Not Available

    1988-06-01

    The objective of this program was to evaluate the merits of using natural gas-fired gas turbine exhaust to directly dry food products. A survey of drying practices utilized in the food industry and a detailed review of worldwide regulatory drying practices were completed. An investigation of the economic advantages associated with direct drying was also considered. Four drying scenarios were used as part of the analysis: Dilution - hot turbine exhaust gases were diluted with ambient air to achieve temperatures suitable for food product drying; Indirect Heat Exchanger - gas turbine exhaust was directed through an intermediate heat exchanger to avoid flue-gas contamination of the ambient air; Tri-Generation - exhaust gases from the gas turbine were first directed to a heat recovery boiler and then through the drying system to dry the food product; and Conventional Cogeneration - the most conventional simple cycle gas turbine cogeneration (this scenario served as the baseline for all evaluations). Although the economics associated with direct drying appear attractive, the principal concern of any potential use would be the extraordinarily high NO/sub x/ levels and the potential nitrate and nitrosamine (potential carcinogens and carcinogenic precursors) contamination in food products. 21 refs., 21 figs., 17 tabs.

  18. Effect of drying conditions on crystallinity of amylose nanoparticles prepared by nanoprecipitation.

    PubMed

    Yan, Xiaoxia; Chang, Yanjiao; Wang, Qian; Fu, Youjia; Zhou, Jiang

    2017-04-01

    In this study, amylose nanoparticles prepared by nanoprecipitation were dried at different conditions. The crystalline structure, crystallinity, re-dispersibility and morphological characteristic of the amylose nanoparticles after drying were investigated. X-ray diffraction analysis revealed that the V-type crystalline structure of the amylose nanoparticles formed in the drying process instead of the precipitation process, and drying condition significantly affects the crystallinity. The temperature cycles drying at 4°C and 40°C considerably increased crystallinity of the amylose nanoparticles, 24h (4/40°C, 12h/12h) drying under 11% relative humidity could give rise to a crystallinity up to 50.05%. The applied drying procedures had no obvious effect on the appearance of the amylose nanoparticles. The Z average-size (d. nm) and polydispersity index (PDI) obtained from dynamic light scattering analysis suggested that the drying processes caused some aggregates, but the dried amylose nanoparticles could be well dispersed in water.

  19. Soil N fluxes in three contrasting dry tropical forests.

    PubMed

    Tokuchi, N; Nakanishi, A; Wachirinrat, C; Takeda, H

    2001-11-20

    A comparative study of N fluxes in soil among a dry dipterocarp forest (DDF), a dry evergreen forest (DEF), and a hill evergreen forest (HEF) in Thailand was done. N fluxes in soil were estimated using an ion exchange resin core method and a buried bag method. Soil C and N pools were 38 C Mg/ha/30 cm and 2.5 N Mg/ha/30 cm in DDF, 82 C Mg/ha/30 cm and 6.2 N Mg/ha/30 cm in DEF, and 167 C Mg/ha/30 cm and 9.3 N Mg/ha/30 cm in HEF. Low C concentration in the DDF and DEF sites was compensated by high fine soil content. In the highly weathered tropical soil, fine soil content seemed to be important for C accumulation. Temporal and vertical fluctuations of N fluxes were different among the sites. The highest N flux was exhibited at the onset of the wet season in DDF, whereas inorganic N production and estimated uptake of N were relatively stable during the wet season in DEF and HEF. It is suggested that N cycling in soil becomes stable in dry tropical forests to intermediate in temperate forests. N deposition may result in large changes of N cycling in the DDF and DEF due to low accumulations of C and N.

  20. Systemic review of dry socket: aetiology, treatment, and prevention.

    PubMed

    Tarakji, Bassel; Saleh, Lubna Ahmed; Umair, Ayesha; Azzeghaiby, Saleh Nasser; Hanouneh, Salah

    2015-04-01

    Our systemic review is to make a comprehensive review about the aetiology, treatment and the prevention of dry socket, the inclusion criteria were all the studies that discuss the dry socket and its etiology, treatment and prevention and exclusion criteria were all the studies that discuss the other complications of tooth extraction, the materials and methods used for this systemic review was to search in the Pub Medline database between 2008 to 2013, using specific words "dry socket, aetiology, treatment and prevention" and published in the English language, the articles were screened by abstract for relevance to aetiology, treatment and prevention of dry socket, 82 papers were identified in pub med but a total of 36 out of Publications were included in the final systemic review according to the specific keywords and materials mentioned above. The occurrence of dry socket in an everyday oral surgery or dental practice is unavoidable. The risk factors are smoking, surgical trauma, single extractions, age, sex, medical history, systemic disorder, extraction site, amount of anaesthesia, operator experience, antibiotics use prior to surgery, difficulty of the surgery and the previous surgical site infection in addition to oral Contraceptives, menstrual cycle and immediate postextraction socket irrigation with normal saline. The traditional options of treatment are directed toward palliative care, such as the irrigation of the surgical site, avoiding curetting the extraction socket, Packing with a zinc oxide- eugenol paste on iodoform gauze can be considered to relieve acute pain episodes, there is also new agents in the market can accelerate the healing of the socket such as PRGF and GECB. The prevention methods include avoiding smoking before and after surgery and a traumatic surgery, the use of antibiotics, such as, azithromycin, can be considered, the other preventive measures such as chlorhecidine rinse or gel can be effective in the reduction of dry socket

  1. Systemic Review of Dry Socket: Aetiology, Treatment, and Prevention

    PubMed Central

    Saleh, Lubna Ahmed; Umair, Ayesha; Azzeghaiby, Saleh Nasser; Hanouneh, Salah

    2015-01-01

    Our systemic review is to make a comprehensive review about the aetiology, treatment and the prevention of dry socket, the inclusion criteria were all the studies that discuss the dry socket and its etiology, treatment and prevention and exclusion criteria were all the studies that discuss the other complications of tooth extraction, the materials and methods used for this systemic review was to search in the Pub Medline database between 2008 to 2013, using specific words “dry socket, aetiology, treatment and prevention” and published in the English language, the articles were screened by abstract for relevance to aetiology, treatment and prevention of dry socket, 82 papers were identified in pub med but a total of 36 out of Publications were included in the final systemic review according to the specific keywords and materials mentioned above. The occurrence of dry socket in an everyday oral surgery or dental practice is unavoidable. The risk factors are smoking, surgical trauma, single extractions, age, sex, medical history, systemic disorder, extraction site, amount of anaesthesia, operator experience, antibiotics use prior to surgery, difficulty of the surgery and the previous surgical site infection in addition to oral Contraceptives, menstrual cycle and immediate postextraction socket irrigation with normal saline. The traditional options of treatment are directed toward palliative care, such as the irrigation of the surgical site, avoiding curetting the extraction socket, Packing with a zinc oxide– eugenol paste on iodoform gauze can be considered to relieve acute pain episodes, there is also new agents in the market can accelerate the healing of the socket such as PRGF and GECB. The prevention methods include avoiding smoking before and after surgery and a traumatic surgery, the use of antibiotics, such as, azithromycin, can be considered, the other preventive measures such as chlorhecidine rinse or gel can be effective in the reduction of dry socket

  2. The Delicate Cycle

    ERIC Educational Resources Information Center

    Galloway, Melinda

    2006-01-01

    There are two types of parenting styles when it comes to parent involvement in their children's education: the "hovering" type and the "dry cleaner" type. Hovering parents are always on hand for every landmark moment of their children while dry cleaner parents show up only when an emergency is imminent. In this article, the author relates her own…

  3. Hanford spent nuclear fuel cold vacuum drying proof of performance test procedure

    SciTech Connect

    McCracken, K.J.

    1998-06-10

    This document provides the test procedure for cold testing of the first article skids for the Cold Vacuum Drying (CVD) process at the Facility. The primary objective of this testing is to confirm design choices and provide data for the initial start-up parameters for the process. The current scope of testing in this document includes design verification, drying cycle determination equipment performance testing of the CVD process and MCC components, heat up and cool-down cycle determination, and thermal model validation.

  4. Spray-freeze-dried dry powder inhalation of insulin-loaded liposomes for enhanced pulmonary delivery.

    PubMed

    Bi, Ru; Shao, Wei; Wang, Qun; Zhang, Na

    2008-11-01

    Nowadays, growing attention has been paid to the pulmonary region as a target for the delivery of peptide and protein drugs, especially macromolecules with systemic effect like insulin, since the pulmonary route exhibits numerous benefits to be an alternative for repeated injection. Furthermore, encapsulation of insulin into liposomal carriers is an attractive way to increase drug retention time and control the drug release in the lung; however, its long-term stability during storage in the reservoir and the process of aerosolization might be suspected when practically applied. Thus, the aim of this study was to design and characterize dry powder inhalation of insulin-loaded liposomes prepared by novel spray-freeze-drying method for enhanced pulmonary delivery. Process variables such as compressed air pressure, pump speed, and concentration were optimized for parameters such as mean particle diameter, moisture content, and fine particle fraction of the produced powders. Influence of different kinds and amounts of lyoprotectants was also evaluated for the best preservation of the drug entrapped in the liposome bilayers after the dehydration-rehydration cycle. The in vivo study of intratracheal instillation of insulin-loaded liposomes to diabetic rats showed successful hypoglycemic effect with low blood glucose level and long-lasting period and a relative pharmacological bioavailability as high as 38.38% in the group of 8 IU/kg dosage.

  5. Toward intradermal vaccination: preparation of powder formulations by collapse freeze-drying.

    PubMed

    Etzl, Elsa E; Winter, Gerhard; Engert, Julia

    2014-03-01

    Intradermal powder immunization is an emerging technique in vaccine delivery. The purpose of this study was to generate powder particles for intradermal injection by freeze-drying and subsequent cryo-milling. Two different freeze-drying protocols were compared, a moderate freeze-drying cycle and an aggressive freeze-drying cycle, which induced a controlled collapse of the sugar matrix. Ovalbumin served as model antigen. The influence of collapse drying and cryo-milling on particle morphology and protein stability was investigated. Cryo-milling generated irregularly shaped particles of size 20-70 µm. The recovery of soluble monomer of ovalbumin was not changed during freeze-drying and after cryo-milling, or after 12 months of storage at 2-8 °C. A slight increase in higher molecular weight aggregates was found in formulations containing the polymer dextran after 12 months of storage at 50 °C. Light obscuration measurements showed an increase in cumulative particle counts after cryo-milling that did not further increase during storage at 2-8 °C for 12 months. The applicability of the cryo-milling process to other therapeutic proteins was shown using recombinant human granulocyte-colony stimulating factor. Collapse freeze-drying and subsequent cryo-milling allows the generation of particles suitable for intradermal powder injection.

  6. Crystallization of trehalose in frozen solutions and its phase behavior during drying.

    PubMed

    Sundaramurthi, Prakash; Patapoff, Thomas W; Suryanarayanan, Raj

    2010-11-01

    (i) To study the crystallization of trehalose in frozen solutions and (ii) to understand the phase transitions during the entire freeze-drying cycle. Aqueous trehalose solution was cooled to -40°C in a custom-designed sample holder. The frozen solution was warmed to -18°C and annealed, and then dried in the sample chamber of the diffractometer. XRD patterns were continuously collected during cooling, annealing and drying. After cooling, hexagonal ice was the only crystalline phase observed. However, upon annealing, crystallization of trehalose dihydrate was evident. Seeding the frozen solution accelerated the solute crystallization. Thus, phase separation of the lyoprotectant was observed in frozen solutions. During drying, dehydration of trehalose dihydrate yielded a substantially amorphous anhydrous trehalose. Crystallization of trehalose, as trehalose dihydrate, was observed in frozen solutions. The dehydration of the crystalline trehalose dihydrate to substantially amorphous anhydrate occurred during drying. Therefore, analyzing the final lyophile will not reveal crystallization of the lyoprotectant during freeze-drying. The lyoprotectant crystallization can only become evident by continuous monitoring of the system during the entire freeze-drying cycle. In light of the phase separation of trehalose in frozen solutions, its ability to serve as a lyoprotectant warrants further investigation.

  7. Crystallization of Trehalose in Frozen Solutions and its Phase Behavior during Drying

    SciTech Connect

    Sundaramurthi, Prakash; Patapoff, Thomas W.; Suryanarayanan, Raj

    2015-02-19

    To study the crystallization of trehalose in frozen solutions and to understand the phase transitions during the entire freeze-drying cycle. Aqueous trehalose solution was cooled to -40 C in a custom-designed sample holder. The frozen solution was warmed to -18 C and annealed, and then dried in the sample chamber of the diffractometer. XRD patterns were continuously collected during cooling, annealing and drying. After cooling, hexagonal ice was the only crystalline phase observed. However, upon annealing, crystallization of trehalose dihydrate was evident. Seeding the frozen solution accelerated the solute crystallization. Thus, phase separation of the lyoprotectant was observed in frozen solutions. During drying, dehydration of trehalose dihydrate yielded a substantially amorphous anhydrous trehalose. Crystallization of trehalose, as trehalose dihydrate, was observed in frozen solutions. The dehydration of the crystalline trehalose dihydrate to substantially amorphous anhydrate occurred during drying. Therefore, analyzing the final lyophile will not reveal crystallization of the lyoprotectant during freeze-drying. The lyoprotectant crystallization can only become evident by continuous monitoring of the system during the entire freeze-drying cycle. In light of the phase separation of trehalose in frozen solutions, its ability to serve as a lyoprotectant warrants further investigation.

  8. Uncertainty analysis as essential step in the establishment of the dynamic Design Space of primary drying during freeze-drying.

    PubMed

    Mortier, Séverine Thérèse F C; Van Bockstal, Pieter-Jan; Corver, Jos; Nopens, Ingmar; Gernaey, Krist V; De Beer, Thomas

    2016-06-01

    compared to the deterministic dynamic Design Space; however, the risk of failure is under control. Experimental verification revealed that only a risk of failure acceptance level of 0.01% yielded a guaranteed zero-defect quality end-product. The computed process settings with a risk of failure acceptance level of 0.01% resulted in a decrease of more than half of the primary drying time in comparison with a regular, conservative cycle with fixed settings. Copyright © 2016. Published by Elsevier B.V.

  9. Cracking in Drying Colloidal Films

    NASA Astrophysics Data System (ADS)

    Singh, Karnail B.; Tirumkudulu, Mahesh S.

    2007-05-01

    It has long been known that thick films of colloidal dispersions such as wet clays, paints, and coatings crack under drying. Although capillary stresses generated during drying have been recently identified as the cause for cracking, the existence of a maximum crack-free film thickness that depends on particle size, rigidity, and packing has not been understood. Here, we identify two distinct regimes for crack-free films based on the magnitude of compressive strain at the maximum attainable capillary pressure and show remarkable agreement of measurements with our theory. We anticipate our results to not only form the basis for design of coating formulations for the paints, coatings, and ceramics industry but also assist in the production of crack-free photonic band gap crystals.

  10. Dry Eye and Designer Ophthalmics

    PubMed Central

    Laurie, Gordon W.; Olsakovsky, Leslie A.; Conway, Brian P.; McKown, Robert L.; Kitagawa, Kazuko; Nichols, Jason J.

    2009-01-01

    EST, proteomic, and antibody capture assays are revealing a level of tear film protein complexity far greater than previously appreciated. A systems biology approach will be needed to fully appreciate function as tear protein doses fluctuate in time through different conditions. Although consensus is growing on what fully constitutes the human tear proteome, questions remain about the source and significance of the ∼256 tear proteins designated as ‘intracellular’. Many of these may derive from normal cellular turnover and could therefore be informative. A further >183 are designated as ‘extracellular’. Surprisingly, only 4 – 5% of these appear to be dysregulated in the three forms of dry eye preliminarily examined to date. Some differ and a couple overlap, suggesting that disease-specific signatures could be identified. Future dry eye treatment might include recombinant tear protein rescue as a personalized ophthalmic approach to ocular surface disease. PMID:18677231

  11. Global soil moisture dry-down analysis based on SMAP retrievals

    NASA Astrophysics Data System (ADS)

    Wang, W.; Lu, H.; Peng, B.; Entekhabi, D.; Pan, M.; Mccoll, K. A.; Akbar, R.; Zhao, T.

    2016-12-01

    The rate at which soil moisture depletes following a precipitation event (the soil moisture dry-down) encodes information on several hydrological parameters, most prominently vertical drainage and evapotranspiration. The initial phase of the dry-down process is usually controlled by vertical drainage and soil hydraulic properties. The second phase is usually controlled by the evapotranspiration rate. Better insight into dry-down processes at global scales will enhance our understanding of soil moisture's role in the terrestrial water cycle. The launch of SMAP gives us unprecedented opportunities for studying dry-down processes globally. In this study, an algorithm for dry-down event detection was developed. Dry-down events are identified globally using one year of SMAP data from April 2015 to March 2016. Three sites spanning different climate zones, including Texas in the USA, southern China, and central Australia, were selected for testing and validation of the algorithm. Results in these sites show that the algorithm can efficiently identify dry-down events. The algorithm was then applied globally. The number of dry-down events, average dry-down duration, and average dry-down slope were estimated based on one year of SMAP data at each grid point. We relate the rate of the dry-down at each location to the time-history of precipitation, seasonal climate and the relative dominance of drainage and evaporation loss processes. The rate of dry-down under difference hydrologic and hydroclimatic regimes is proposed to be a rigorous test of how well land surface models capture and incorporate physical processes and land memory.

  12. Characterizing differences in precipitation regimes of extreme wet and dry years: implications for climate change experiments.

    PubMed

    Knapp, Alan K; Hoover, David L; Wilcox, Kevin R; Avolio, Meghan L; Koerner, Sally E; La Pierre, Kimberly J; Loik, Michael E; Luo, Yiqi; Sala, Osvaldo E; Smith, Melinda D

    2015-02-03

    Climate change is intensifying the hydrologic cycle and is expected to increase the frequency of extreme wet and dry years. Beyond precipitation amount, extreme wet and dry years may differ in other ways, such as the number of precipitation events, event size, and the time between events. We assessed 1614 long-term (100 year) precipitation records from around the world to identify key attributes of precipitation regimes, besides amount, that distinguish statistically extreme wet from extreme dry years. In general, in regions where mean annual precipitation (MAP) exceeded 1000 mm, precipitation amounts in extreme wet and dry years differed from average years by ~40% and 30%, respectively. The magnitude of these deviations increased to >60% for dry years and to >150% for wet years in arid regions (MAP<500 mm). Extreme wet years were primarily distinguished from average and extreme dry years by the presence of multiple extreme (large) daily precipitation events (events >99th percentile of all events); these occurred twice as often in extreme wet years compared to average years. In contrast, these large precipitation events were rare in extreme dry years. Less important for distinguishing extreme wet from dry years were mean event size and frequency, or the number of dry days between events. However, extreme dry years were distinguished from average years by an increase in the number of dry days between events. These precipitation regime attributes consistently differed between extreme wet and dry years across 12 major terrestrial ecoregions from around the world, from deserts to the tropics. Thus, we recommend that climate change experiments and model simulations incorporate these differences in key precipitation regime attributes, as well as amount into treatments. This will allow experiments to more realistically simulate extreme precipitation years and more accurately assess the ecological consequences. © 2015 John Wiley & Sons Ltd.

  13. Superficial versus deep dry needling.

    PubMed

    Baldry, Peter

    2002-08-01

    Ninety percent of my patients with myofascial trigger point (MTrP) pain have this alone and are treated with superficial dry needling. Approximately 10% have concomitant MTrP pain and nerve root compression pain. These are treated with deep dry needling. SUPERFICIAL DRY NEEDLING (SDN): The activated and sensitised nociceptors of a MTrP cause it to be so exquisitely tender that firm pressure applied to it gives rise to a flexion withdrawal reflex (jump sign) and in some cases the utterance of an expletive (shout sign). The optimum strength of SDN at a MTrP site is the minimum necessary to abolish these two reactions. With respect to this patients are divided into strong, average and weak responders. The responsiveness of each individual is determined by trial and error. It is my practice to insert a needle (0.3mm x 30mm) into the tissues immediately overlying the MTrP to a depth of 5-10 mm and to leave it in situ long enough for the two reactions to be abolished. For an average reactor this is about 30secs. For a weak reactor it is several minutes. And for a strong reactor the insertion of the needle and its immediate withdrawal is all that is required. Following treatment muscle stretching exercises should be carried out, and any steps taken to eliminate factors that might lead to the reactivation of the MTrPs. DEEP DRY NEEDLING (DDN): This in my practice is only used either when primary MTrP activity causes shortening of muscle sufficient enough to bring about compression of nerve roots. Or when there is nerve compression pain usually from spondylosis or disc prolapse and the secondary development of MTrP activity. Unlike SDN, DDN is a painful procedure and one which gives rise to much post-treatment soreness.

  14. FUEL CYCLE POTENTIAL WASTE FOR DISPOSITION

    SciTech Connect

    Carter, J.

    2011-01-03

    The United States (U.S.) currently utilizes a once-through fuel cycle where used nuclear fuel (UNF) is stored on-site in either wet pools or in dry storage systems with ultimate disposal in a deep mined geologic repository envisioned. Within the Department of Energy's (DOE) Office of Nuclear Energy (DOE-NE), the Fuel Cycle Research and Development Program (FCR&D) develops options to the current commercial fuel cycle management strategy to enable the safe, secure, economic, and sustainable expansion of nuclear energy while minimizing proliferation risks by conducting research and development of advanced fuel cycles, including modified open and closed cycles. The safe management and disposition of used nuclear fuel and/or nuclear waste is a fundamental aspect of any nuclear fuel cycle. Yet, the routine disposal of used nuclear fuel and radioactive waste remains problematic. Advanced fuel cycles will generate different quantities and forms of waste than the current LWR fleet. This study analyzes the quantities and characteristics of potential waste forms including differing waste matrices, as a function of a variety of potential fuel cycle alternatives including: (1) Commercial UNF generated by uranium fuel light water reactors (LWR). Four once through fuel cycles analyzed in this study differ by varying the assumed expansion/contraction of nuclear power in the U.S. (2) Four alternative LWR used fuel recycling processes analyzed differ in the reprocessing method (aqueous vs. electro-chemical), complexity (Pu only or full transuranic (TRU) recovery) and waste forms generated. (3) Used Mixed Oxide (MOX) fuel derived from the recovered Pu utilizing a single reactor pass. (4) Potential waste forms generated by the reprocessing of fuels derived from recovered TRU utilizing multiple reactor passes.

  15. FUEL CYCLE POTENTIAL WASTE FOR DISPOSITION

    SciTech Connect

    Jones, R.; Carter, J.

    2010-10-13

    The United States (U.S.) currently utilizes a once-through fuel cycle where used nuclear fuel (UNF) is stored on-site in either wet pools or in dry storage systems with ultimate disposal in a deep mined geologic repository envisioned. Within the Department of Energy's (DOE) Office of Nuclear Energy (DOE-NE), the Fuel Cycle Research and Development Program (FCR&D) develops options to the current commercial fuel cycle management strategy to enable the safe, secure, economic, and sustainable expansion of nuclear energy while minimizing proliferation risks by conducting research and development of advanced fuel cycles, including modified open and closed cycles. The safe management and disposition of used nuclear fuel and/or nuclear waste is a fundamental aspect of any nuclear fuel cycle. Yet, the routine disposal of used nuclear fuel and radioactive waste remains problematic. Advanced fuel cycles will generate different quantities and forms of waste than the current LWR fleet. This study analyzes the quantities and characteristics of potential waste forms including differing waste matrices, as a function of a variety of potential fuel cycle alternatives including: (1) Commercial UNF generated by uranium fuel light water reactors (LWR). Four once through fuel cycles analyzed in this study differ by varying the assumed expansion/contraction of nuclear power in the U.S; (2) Four alternative LWR used fuel recycling processes analyzed differ in the reprocessing method (aqueous vs. electro-chemical), complexity (Pu only or full transuranic (TRU) recovery) and waste forms generated; (3) Used Mixed Oxide (MOX) fuel derived from the recovered Pu utilizing a single reactor pass; and (4) Potential waste forms generated by the reprocessing of fuels derived from recovered TRU utilizing multiple reactor passes.

  16. Menstrual Cycle Problems

    MedlinePlus

    ... Read MoreDepression in Children and TeensRead MoreBMI Calculator Menstrual Cycle ProblemsFrom missed periods to painful periods, menstrual cycle problems are common, but usually not serious. Follow ...

  17. McMurdo Dry Valleys

    NASA Technical Reports Server (NTRS)

    2002-01-01

    One of the few areas of Antarctica not covered by thousands of meters of ice, the McMurdo Dry Valleys stand out in this satellite image. For a few weeks each summer temperatures are warm enough to melt glacial ice, creating streams that feed freshwater lakes that lie at the bottom of the valleys. Beneath a cap of ice these lakes remains unfrozen year-round, supporting colonies of bacteria and phytoplankton. Over the past 14 years, however, summers have been colder than usual, and the lakes are becoming more and more frozen. If the trend continues, the biological communities they support may go into hibernation. Most of Antarctica has cooled along with the Dry Valleys, in contrast to much of the rest of the Earth, which has warmed over the past 100 years. No one knows if the trend is related to global climate, or just a quirk in the weather. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) instrument on December 18, 1999. For more information, visit: National Public Radio's Mixed Signals from Antarctica Declassified Satellite Imagery of the McMurdo Dry Valleys Image by Robert Simmon, based on data provided by the NASA GSFC Oceans and Ice Branch and the Landsat 7 Science Team

  18. Ingested hyaluronan moisturizes dry skin

    PubMed Central

    2014-01-01

    Hyaluronan (HA) is present in many tissues of the body and is essential to maintain moistness in the skin tissues, which contain approximately half the body’s HA mass. Due to its viscosity and moisturizing effect, HA is widely distributed as a medicine, cosmetic, food, and, recently marketed in Japan as a popular dietary supplement to promote skin moisture. In a randomized, double-blind, placebo-controlled clinical study it was found that ingested HA increased skin moisture and improved treatment outcomes for patients with dry skin. HA is also reported to be absorbed by the body distributed, in part, to the skin. Ingested HA contributes to the increased synthesis of HA and promotes cell proliferation in fibroblasts. These effects show that ingestion of HA moisturizes the skin and is expected to improve the quality of life for people who suffer from dry skin. This review examines the moisturizing effects of dry skin by ingested HA and summarizes the series of mechanisms from absorption to pharmacological action. PMID:25014997

  19. Skin aging and dry skin.

    PubMed

    Hashizume, Hideo

    2004-08-01

    Skin aging appears to be the result of both scheduled and continuous "wear and tear" processes that damage cellular DNA and proteins. Two types of aging, chronological skin aging and photoaging, have distinct clinical and histological features. Chronological skin aging is a universal and inevitable process characterized primarily by physiologic alterations in skin function. In this case, keratinocytes are unable to properly terminally differentiate to form a functional stratum corneum, and the rate of formation of neutral lipids that contribute to the barrier function slows, causing dry, pale skin with fine wrinkles. In contrast, photoaging results from the UVR of sunlight and the damage thus becomes apparent in sun-exposed skin. Characteristics of this aging type are dry and sallow skin displaying fine wrinkles as well as deep furrows, resulting from the disorganization of epidermal and dermal components associated with elastosis and heliodermatitis. Understanding of the functions of the skin and the basic principles of moisturizer use and application is important for the prevention of skin aging. Successful treatment of dry skin with appropriate skin care products gives the impression of eternal youth.

  20. Defect management on photomasks with dry treatment assistance

    NASA Astrophysics Data System (ADS)

    Shi, Irene; Guo, Eric; Lu, Max

    2016-10-01

    One of the key challenges of photomask manufacture is to achieve defect-free masks. Clean and repair has been applied to manage defects and particles on the mask imported during manufacturing processes. Since photomask patterns become smaller and more complicated as integrated circuit (IC) scaling to 28 nm node and below, the increasingly importance of mask quality compels us continuously research on more effective defect treatment solutions, to achieve mask yield enhancement and on-schedule delivery. In this paper, we would like to introduce new approaches of defect management with dry treatment assistance, according to particular defect types. One is using plasma etching gases of Cl2/O2 to change the properties of glue compounds adhering to the mask surface, and make them removed by conventional cleaning. Another is the application of O2 plasma dry treatment for the benefit of alleviation on scan damage phenomenon, which comes from contamination on the scan area due to excessive repair cycles.

  1. Microalgal drying and cell disruption--recent advances.

    PubMed

    Show, Kuan-Yeow; Lee, Duu-Jong; Tay, Joo-Hwa; Lee, Tse-Min; Chang, Jo-Shu

    2015-05-01

    Production of intracellular metabolites or biofuels from algae involves various processing steps, and extensive work on laboratory- and pilot-scale algae cultivation, harvesting and processing has been reported. As algal drying and cell disruption are integral processes of the unit operations, this review examines recent advances in algal drying and disruption for nutrition or biofuel production. Challenges and prospects of the processing are also outlined. Engineering improvements in addressing the challenges of energy efficiency and cost-effective and rigorous techno-economic analyses for a clearer prospect comparison between different processing methods are highlighted. Holistic life cycle assessments need to be conducted in assessing the energy balance and the potential environmental impacts of algal processing. The review aims to provide useful information for future development of efficient and commercially viable algal food products and biofuels production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. HIV Life Cycle

    MedlinePlus

    HIV Overview The HIV Life Cycle (Last updated 9/13/2016; last reviewed 9/8/2016) Key Points HIV gradually destroys the immune ... life cycle. What is the connection between the HIV life cycle and HIV medicines? Antiretroviral therapy (ART) ...

  3. Why the Learning Cycle?

    ERIC Educational Resources Information Center

    Marek, Edmund A.

    2008-01-01

    The learning cycle is a way to structure inquiry in school science and occurs in several sequential phases. A learning cycle moves children through a scientific investigation by having them first explore materials, then construct a concept, and finally apply or extend the concept to other situations. Why the learning cycle? Because it is a…

  4. Cycling To Awareness.

    ERIC Educational Resources Information Center

    Kozak, Stan

    1999-01-01

    Encourages environmental and outdoor educators to promote bicycling. In the community and the curriculum, cycling connects environmental issues, health and fitness, law and citizenship, appropriate technology, and the joy of being outdoors. Describes the Ontario Cycling Association's cycling strategy and its four components: school cycling…

  5. Sensitivity Variation on Low Cycle Fatigue Cracks Using Level 4/Method B Penetrant

    SciTech Connect

    FULWOOD,HARRY; MOORE,DAVID G.

    1999-09-02

    The Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) is currently conducting experiments with Level 4, Method B penetrant on low cycle fatigue specimens. The main focus of these experiments is to document the affect on penetrant brightness readings by varying inspection parameters. This paper discusses the results of changing drying temperature, drying time, and dwell time of both penetrant and emulsifier on low cycle fatigue specimens.

  6. 27 CFR 24.202 - Dried fruit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... deficient in sugar, sufficient pure dry sugar may be added to increase the total solids content to 25... exclusive of pulp). Pure dry sugar may be used for sweetening. After complete fermentation or...

  7. 27 CFR 24.202 - Dried fruit.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... deficient in sugar, sufficient pure dry sugar may be added to increase the total solids content to 25... exclusive of pulp). Pure dry sugar may be used for sweetening. After complete fermentation or...

  8. 27 CFR 24.202 - Dried fruit.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... deficient in sugar, sufficient pure dry sugar may be added to increase the total solids content to 25... exclusive of pulp). Pure dry sugar may be used for sweetening. After complete fermentation or...

  9. 27 CFR 24.202 - Dried fruit.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... deficient in sugar, sufficient pure dry sugar may be added to increase the total solids content to 25... exclusive of pulp). Pure dry sugar may be used for sweetening. After complete fermentation or...

  10. Thin layer solar drying of rough rice

    SciTech Connect

    Zaman, M.A.; Bala, B.K. )

    1989-01-01

    This paper presents a set of simple empirical equations for natural air flow solar drying of rough rice in mixed-mode type dryer, box-type dryer and open floor drying system. The moisture contents predicted by the equations were in good agreement with the observed values. The effect of drying air temperature on the drying rate constants for these three cases were found to be insignificant. The equilibrium moisture content appeared to be the most important variable controlling the drying rate. The highest drying rate was observed in case of mixed-mode dryer. The drying rate of box dryer was next to that of mixed-mode dryer. This study shows that the introduction of solar dryer for drying of rough rice is highly recommended in Bangladesh.

  11. Drying and recovery of aerobic granules.

    PubMed

    Hu, Jianjun; Zhang, Quanguo; Chen, Yu-You; Lee, Duu-Jong

    2016-10-01

    To dehydrate aerobic granules to bone-dry form was proposed as a promising option for long-term storage of aerobic granules. This study cultivated aerobic granules with high proteins/polysaccharide ratio and then dried these granules using seven protocols: drying at 37°C, 60°C, 4°C, under sunlight, in dark, in a flowing air stream or in concentrated acetone solutions. All dried granules experienced volume shrinkage of over 80% without major structural breakdown. After three recovery batches, although with loss of part of the volatile suspended solids, all dried granules were restored most of their original size and organic matter degradation capabilities. The strains that can survive over the drying and storage periods were also identified. Once the granules were dried, they can be stored over long period of time, with minimal impact yielded by the applied drying protocols. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Simple Solutions for Treating Dry Mouth

    MedlinePlus

    Patient Education Sheet Simple Solutions for Treating Dry Mouth Clinicians: Please make as many copies of this ... Philadelphia, for authoring “Simple Solutions for Treating Dry Mouth.” Ask your family doctor to discontinue or provide ...

  13. Dry Mouth? Don't Delay Treatment

    MedlinePlus

    ... Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products For Consumers Home For Consumers Consumer Updates Dry Mouth? Don' ... or neck cancer. back to top Advice for Consumers If you have persistent dry mouth: Talk to ...

  14. Nanoceria: a Potential Therapeutic for Dry AMD.

    PubMed

    Cai, Xue; McGinnis, James F

    2016-01-01

    Age-related macular degeneration (AMD) is the leading cause of blinding diseases. The "dry" form of AMD is the most common form of AMD. In contrast to the treatable neovascular (wet) AMD, no effective treatment is available for dry AMD. In this review, we summarize the animal models and therapeutic strategies for dry AMD. The novel candidates as potential treatment targets and the potential effectiveness of nanoceria as a treatment of dry AMD are also discussed.

  15. Air drying of softwood lumber, Fairbanks, Alaska.

    Treesearch

    George R Sampson; Forrest A. Ruppert

    1985-01-01

    Air-drying rates for two stacks of 2-inch-thick white spruce were observed in the Fairbanks area during summer 1982. The air-drying rate for the same size lumber was also observed during winter 1982-83. Very little drying occurred during the winter. Drying rates in summer were correlated with average daily temperature and average daily dew point to derive predictive...

  16. Accelerating oak air drying by presurfacing

    Treesearch

    W. T. Simpson; R. C. Baltes

    1972-01-01

    A comparison was made between the air-drying rates of rough and presurfaced northern red oak and white oak. In both species, the presurfaced material was about 1/8 inch thinner than the rough material and dried faster than the rough material. The reduction in drying time depends on the method of analyzing the drying curves, but is slightly less than 10 percent.

  17. Drying and color characteristics of coriander foliage using convective thin-layer and microwave drying.

    PubMed

    Shaw, Mark; Meda, Venkatesh; Tabil, Lope; Opoku, Anthony

    2007-01-01

    Heat sensitive properties (aromatic, medicinal, color) provide herbs and spices with their high market value. In order to prevent extreme loss of heat sensitive properties when drying herbs, they are normally dried at low temperatures for longer periods of time to preserve these sensory properties. High energy consumption often results from drying herbs over a long period. Coriander (Coriandrum sativum L., Umbelliferae) was dehydrated in two different drying units (thin layer convection and microwave dryers) in order to compare the drying and final product quality (color) characteristics. Microwave drying of the coriander foliage was faster than convective drying. The entire drying process took place in the falling rate period for both microwave and convective dried samples. The drying rate for the microwave dried samples ranged from 42.3 to 48.2% db/min and that of the convective dried samples ranged from 7.1 to 12.5% db/min. The fresh sample color had the lowest L value at 26.83 with higher L values for all dried samples. The results show that convective thin layer dried coriander samples exhibited a significantly greater color change than microwave dried coriander samples. The color change index values for the microwave dried samples ranged from 2.67 to 3.27 and that of the convective dried samples varied from 4.59 to 6.58.

  18. The microbial cell cycle

    SciTech Connect

    Nurse, P.; Streiblova, E.

    1984-01-01

    This book concentrates on the major problems of cell cycle control in microorganisms. A wide variety of microorganisms, ranging from bacteria and yeasts to hyphal fungi, algae, and ciliates are analyzed, with emphasis on the basic similarities among the organisms. Different ways of looking at cell cycle control which emphasize aspects of the problem such as circadian rhythms, limit cycle oscillators, and cell size models, are considered. New approaches such as the study of cell cycle mutants, and cloning of cell cycle control genes are also presented.

  19. Composite drying with simultaneous vacuum and toggling

    USDA-ARS?s Scientific Manuscript database

    Drying is an important mechanical operation in the leather making process. Leather acquires its final texture, consistency and flexibility in the drying operation. Vacuum drying offers fast water removal at a low temperature, which is particularly advantageous to heat-vulnerable chrome-free leathe...

  20. Composite drying with simultaneous vacuum and toggling

    USDA-ARS?s Scientific Manuscript database

    Drying is one of key steps to govern the physical properties of leather and it is where leather acquires its final texture, consistency and flexibility. Recently we have been working diligently to improve chrome-free leather by optimizing its drying process. We developed a drying method using a co...

  1. Compton Dry-Cask Imaging System

    SciTech Connect

    2011-01-01

    The Compton-Dry Cask Imaging Scanner is a system that verifies and documents the presence of spent nuclear fuel rods in dry-cask storage and determines their isotopic composition without moving or opening the cask. For more information about this project, visit http://www.inl.gov/rd100/2011/compton-dry-cask-imaging-system/

  2. Techniques for drying thick southern pine veneer

    Treesearch

    Peter Koch

    1964-01-01

    Thick veneers cut from southern pine are relatively easy to dry, but they are not easy to dry free of distortion. The research reported here was undertaken to compare five drying systems. Factors evaluated included rate of water loss, degree of distortion, and the effect on strength. Effects on gluability were also briefly studied.

  3. Quality drying of softwood lumber : guidebook - checklist

    Treesearch

    M. R. Milota; J. D. Danielson; R. S. Boone; D. W. Huber

    The IMPROVE Lumber Drying Program is intended to increase awareness of the lumber drying system as a critical component in the manufacture of quality lumber. One objective of the program is to provide easy-to-use tools that a kiln operator can use to maintain an efficient kiln operation and therefore contribute to lumber drying quality. This report is one component of...

  4. Quality drying of hardwood lumber : guidebook -- checklist

    Treesearch

    R. S. Boone; M. R. Milota; J. D. Danielson; D. W. Huber

    The IMPROVE Lumber Drying Program is intended to increase awareness of the lumber drying system as a critical component in the manufacture of quality lumber. One objective of the program is to provide easy-to-use tools that a kiln operator can use to maintain an efficient kiln operation and therefore improve lumber drying quality. This report is one component of the...

  5. Accelerating the kiln drying of oak

    Treesearch

    William T. Simpson

    1980-01-01

    Reducing kiln-drying time for oak lumber can reduce energy requirements as well as reduce lumber inventories. In this work, l-inch northern red oak and white oak were kiln dried from green by a combination of individual accelerating techniques– presurfacing, presteaming, accelerated and smooth schedule, and high-temperature drying below 18 percent moisture content....

  6. Compton Dry-Cask Imaging System

    ScienceCinema

    None

    2016-07-12

    The Compton-Dry Cask Imaging Scanner is a system that verifies and documents the presence of spent nuclear fuel rods in dry-cask storage and determines their isotopic composition without moving or opening the cask. For more information about this project, visit http://www.inl.gov/rd100/2011/compton-dry-cask-imaging-system/

  7. 7 CFR 51.2287 - Well dried.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well dried. 51.2287 Section 51.2287 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.2287 Well dried. Well dried means that the portion of kernel is firm and crisp, not pliable...

  8. 7 CFR 51.2287 - Well dried.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well dried. 51.2287 Section 51.2287 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2287 Well dried. Well dried...

  9. 7 CFR 51.2086 - Well dried.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well dried. 51.2086 Section 51.2086 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Well dried. Well dried means that the kernel is firm and brittle, not pliable or leathery....

  10. 7 CFR 51.2961 - Well dried.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well dried. 51.2961 Section 51.2961 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Walnuts in the Shell Definitions § 51.2961 Well dried. Well dried means that...

  11. 7 CFR 51.1444 - Well dried.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well dried. 51.1444 Section 51.1444 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Shelled Pecans Definitions § 51.1444 Well dried. Well dried means that the...

  12. 7 CFR 51.2086 - Well dried.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well dried. 51.2086 Section 51.2086 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Almonds in the Shell Definitions § 51.2086 Well dried. Well dried means that...

  13. 7 CFR 51.2119 - Well dried.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well dried. 51.2119 Section 51.2119 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Shelled Almonds Definitions § 51.2119 Well dried. Well dried means that the...

  14. 7 CFR 51.2961 - Well dried.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well dried. 51.2961 Section 51.2961 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Well dried. Well dried means that the kernel is firm and crisp, not pliable or leathery....

  15. 7 CFR 51.2119 - Well dried.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well dried. 51.2119 Section 51.2119 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Shelled Almonds Definitions § 51.2119 Well dried. Well dried means that the kernel is firm and brittle, and not pliable or leathery....

  16. 7 CFR 51.2119 - Well dried.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well dried. 51.2119 Section 51.2119 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Shelled Almonds Definitions § 51.2119 Well dried. Well dried means that the...

  17. 7 CFR 51.2086 - Well dried.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well dried. 51.2086 Section 51.2086 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Almonds in the Shell Definitions § 51.2086 Well dried. Well dried means that...

  18. 7 CFR 51.2119 - Well dried.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well dried. 51.2119 Section 51.2119 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Shelled Almonds Definitions § 51.2119 Well dried. Well dried means that the kernel is firm and brittle, and not pliable or leathery....

  19. 7 CFR 51.2961 - Well dried.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well dried. 51.2961 Section 51.2961 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Walnuts in the Shell Definitions § 51.2961 Well dried. Well dried means that...

  20. 7 CFR 51.2961 - Well dried.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well dried. 51.2961 Section 51.2961 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Well dried. Well dried means that the kernel is firm and crisp, not pliable or leathery....

  1. 7 CFR 51.1444 - Well dried.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well dried. 51.1444 Section 51.1444 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Shelled Pecans Definitions § 51.1444 Well dried. Well dried means that the...

  2. 7 CFR 51.2287 - Well dried.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well dried. 51.2287 Section 51.2287 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2287 Well dried. Well dried...

  3. 7 CFR 51.1444 - Well dried.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well dried. 51.1444 Section 51.1444 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Shelled Pecans Definitions § 51.1444 Well dried. Well dried means that the portion of kernel is firm and crisp, not pliable or leathery....

  4. 7 CFR 51.1444 - Well dried.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well dried. 51.1444 Section 51.1444 Agriculture..., CERTIFICATION, AND STANDARDS) United States Standards for Grades of Shelled Pecans Definitions § 51.1444 Well dried. Well dried means that the portion of kernel is firm and crisp, not pliable or leathery....

  5. 7 CFR 51.2287 - Well dried.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well dried. 51.2287 Section 51.2287 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.2287 Well dried. Well dried means that the portion of kernel is firm and crisp, not pliable...

  6. 7 CFR 51.2119 - Well dried.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well dried. 51.2119 Section 51.2119 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Shelled Almonds Definitions § 51.2119 Well dried. Well dried means that the...

  7. 7 CFR 51.2086 - Well dried.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well dried. 51.2086 Section 51.2086 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Almonds in the Shell Definitions § 51.2086 Well dried. Well dried means that...

  8. 7 CFR 51.2287 - Well dried.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well dried. 51.2287 Section 51.2287 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Shelled English Walnuts (Juglans Regia) Definitions § 51.2287 Well dried. Well dried...

  9. 7 CFR 51.2086 - Well dried.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well dried. 51.2086 Section 51.2086 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Well dried. Well dried means that the kernel is firm and brittle, not pliable or leathery....

  10. 7 CFR 51.2961 - Well dried.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well dried. 51.2961 Section 51.2961 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Walnuts in the Shell Definitions § 51.2961 Well dried. Well dried means that...

  11. 7 CFR 51.1444 - Well dried.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well dried. 51.1444 Section 51.1444 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Shelled Pecans Definitions § 51.1444 Well dried. Well dried means that the...

  12. Introduction to combined cycles

    NASA Astrophysics Data System (ADS)

    Moore, M. J.

    Ideas and concepts underlying the technology of combined cycles including the scientific principles involved and the reasons these cycles are in fashion at the present time, are presented. A cycle is a steady flow process for conversion of heat energy into work, in which a working medium passes through a range of states, returning to its original state. Cycles for power production are the steam cycle, which is a closed cycle, and the gas turbine, which represents an open cycle. Combined cycle thermodynamic parameters, are discussed. The general arrangement of the plant is outlined and important features of their component parts described. The scope for future development is discussed. It is concluded that for the next few years the natural gas fired combined cycle will be the main type of plant installed for electricity generation and cogeneration. Whilst gas turbines may not increase substantially in unit size, there remains scope for further increase in firing temperature with consequent increase in cycle performance. However the larger global reserves of coal are providing an incentive to the development of plant for clean coal combustion using the inherent advantage of the combined cycle to attain high efficiencies.

  13. Infrared thermography for monitoring of freeze-drying processes: instrumental developments and preliminary results.

    PubMed

    Emteborg, Håkan; Zeleny, Reinhard; Charoud-Got, Jean; Martos, Gustavo; Lüddeke, Jörg; Schellin, Holger; Teipel, Katharina

    2014-07-01

    Coupling an infrared (IR) camera to a freeze dryer for on-line monitoring of freeze-drying cycles is described for the first time. Normally, product temperature is measured using a few invasive Pt-100 probes, resulting in poor spatial resolution. To overcome this, an IR camera was placed on a process-scale freeze dryer. Imaging took place every 120 s through a Germanium window comprising 30,000 measurement points obtained contact-free from -40 °C to 25 °C. Results are presented for an empty system, bulk drying of cheese slurry, and drying of 1 mL human serum in 150 vials. During freezing of the empty system, differences of more than 5 °C were measured on the shelf. Adding a tray to the empty system, a difference of more than 8 °C was observed. These temperature differences probably cause different ice structures affecting the drying speed during sublimation. A temperature difference of maximum 13 °C was observed in bulk mode during sublimation. When drying in vials, differences of more than 10 °C were observed. Gradually, the large temperature differences disappeared during secondary drying and products were transformed into uniformly dry cakes. The experimental data show that the IR camera is a highly versatile on-line monitoring tool for different kinds of freeze-drying processes.

  14. Infrared Thermography for Monitoring of Freeze-Drying Processes: Instrumental Developments and Preliminary Results

    PubMed Central

    Emteborg, Håkan; Zeleny, Reinhard; Charoud-Got, Jean; Martos, Gustavo; Lüddeke, Jörg; Schellin, Holger; Teipel, Katharina

    2014-01-01

    Coupling an infrared (IR) camera to a freeze dryer for on-line monitoring of freeze-drying cycles is described for the first time. Normally, product temperature is measured using a few invasive Pt-100 probes, resulting in poor spatial resolution. To overcome this, an IR camera was placed on a process-scale freeze dryer. Imaging took place every 120 s through a Germanium window comprising 30,000 measurement points obtained contact-free from −40°C to 25°C. Results are presented for an empty system, bulk drying of cheese slurry, and drying of 1 mL human serum in 150 vials. During freezing of the empty system, differences of more than 5°C were measured on the shelf. Adding a tray to the empty system, a difference of more than 8°C was observed. These temperature differences probably cause different ice structures affecting the drying speed during sublimation. A temperature difference of maximum 13°C was observed in bulk mode during sublimation. When drying in vials, differences of more than 10°C were observed. Gradually, the large temperature differences disappeared during secondary drying and products were transformed into uniformly dry cakes. The experimental data show that the IR camera is a highly versatile on-line monitoring tool for different kinds of freeze-drying processes. © 2014 European Union 103:2088–2097, 2014 PMID:24902839

  15. Thermal resistance of naturally occurring airborne bacterial spores. [Viking spacecraft dry heat decontamination simulation

    NASA Technical Reports Server (NTRS)

    Puleo, J. R.; Bergstrom, S. L.; Peeler, J. T.; Oxborrow, G. S.

    1978-01-01

    Simulation of a heat process used in the terminal dry-heat decontamination of the Viking spacecraft is reported. Naturally occurring airborne bacterial spores were collected on Teflon ribbons in selected spacecraft assembly areas and subsequently subjected to dry heat. Thermal inactivation experiments were conducted at 105, 111.7, 120, 125, 130, and 135 C with a moisture level of 1.2 mg of water per liter. Heat survivors were recovered at temperatures of 135 C when a 30-h heating cycle was employed. Survivors were recovered from all cycles studied and randomly selected for identification. The naturally occurring spore population was reduced an average of 2.2 to 4.4 log cycles from 105 to 135 C. Heating cycles of 5 and 15 h at temperature were compared with the standard 30-h cycle at 111.7, 120, and 125 C. No significant differences in inactivation (alpha = 0.05) were observed between 111.7 and 120 C. The 30-h cycle differs from the 5- and 15-h cycles at 125 C. Thus, the heating cycle can be reduced if a small fraction (about 0.001 to 0.0001) of very resistant spores can be tolerated.

  16. Thermal resistance of naturally occurring airborne bacterial spores. [Viking spacecraft dry heat decontamination simulation

    NASA Technical Reports Server (NTRS)

    Puleo, J. R.; Bergstrom, S. L.; Peeler, J. T.; Oxborrow, G. S.

    1978-01-01

    Simulation of a heat process used in the terminal dry-heat decontamination of the Viking spacecraft is reported. Naturally occurring airborne bacterial spores were collected on Teflon ribbons in selected spacecraft assembly areas and subsequently subjected to dry heat. Thermal inactivation experiments were conducted at 105, 111.7, 120, 125, 130, and 135 C with a moisture level of 1.2 mg of water per liter. Heat survivors were recovered at temperatures of 135 C when a 30-h heating cycle was employed. Survivors were recovered from all cycles studied and randomly selected for identification. The naturally occurring spore population was reduced an average of 2.2 to 4.4 log cycles from 105 to 135 C. Heating cycles of 5 and 15 h at temperature were compared with the standard 30-h cycle at 111.7, 120, and 125 C. No significant differences in inactivation (alpha = 0.05) were observed between 111.7 and 120 C. The 30-h cycle differs from the 5- and 15-h cycles at 125 C. Thus, the heating cycle can be reduced if a small fraction (about 0.001 to 0.0001) of very resistant spores can be tolerated.

  17. Creep of dry clinopyroxene aggregates

    NASA Astrophysics Data System (ADS)

    Bystricky, Misha; Mackwell, Stephen

    2001-01-01

    We have determined diffusional and dislocation creep rheologies for clinopyroxenite Ca1.0Mg0.8Fe0.2Si2O6 under dry conditions by deforming natural and hot-pressed samples at confining pressures of 300-430 MPa and temperatures of 1100°-1250°C with the oxygen fugacity buffered by either nickel-nickel oxide or iron-wüstite powders. The coarse-grained natural Sleaford Bay clinopyroxenite yielded a stress exponent of n = 4.7 ± 0.2 and an activation energy for creep of Q = 760 ± 40 kJ mol-1, consistent with deformation in the dislocation creep regime. The strength of the natural clinopyroxenite is consistent with previous high-temperature measurements of dislocation creep behavior of Sleaford Bay clinopyroxenite by Kirby and Kronenberg [1984] and Boland and Tullis [1986]. Fine-grained clinopyroxenite was prepared from ground powders of the natural clinopyroxenite. Hot-pressed samples were deformed under similar conditions to the natural samples. Mixed-mode deformation behavior was observed, with diffusional creep (n = 1) at lower differential stresses and dislocation creep (with n and Q similar to those of the natural samples) at higher differential stresses. Within the dislocation creep field the predried hot-pressed samples generally yielded creep rates that were about an order of magnitude faster than the natural samples. Thus, even at the highest differential stresses, a component of strain accommodation by grain boundary diffusion was present in the hot-pressed samples. Optical and electron microscope investigations of the deformation microstructures of the natural and hot-pressed samples show evidence for mechanical twinning and activation of dislocation slip systems. When extrapolated to geological conditions expected in the deep crust and upper mantle on Earth and other terrestrial planets, the strength of dry single-phase clinopyroxene aggregates is very high, exceeding that of dry olivine-rich rocks.

  18. Zinder: a city running dry.

    PubMed

    Price, T

    1993-01-01

    In the West African Sahel lies the old Hausa city of Zinder, Niger. Since the last few decades, it has constantly faced considerable population growth (19,300-119,8000 between 1960 and 1980) while its acute problems with the water supply are increasing. The dry regional climate compounds the problems. In the past, Zinder was a trade center between northern and sub-Saharan Africa as well as being the colonial capital of Niger (1911-26). Its economic and political position has fallen greatly with independence. Lower than average rainfall and the disastrous droughts of the 1970s and 1980s have seriously diminished the region's economic base, e.g., the average annual rainfall in 1930-60 was 535 mm, but by the 1980s, it was only 355 mm. Zinder sits on an elevated, rocky hill which is encircled by dry river valleys and there are no major permanent bodies of water in the vicinity. Impenetrable layers of stone prevent the digging of wells within the city, so the city depends on wells in nearby valleys. The reduced rainfall hinders replenishment of the aquifer, resulting in a drop in the availability of water for daily consumption from 6500 to 3500 sq m. Per capita water consumption in Zinder is much lower than the national average (55 1/day vs. about 100 1/day). The drought in 1992 caused per capita consumption to fall to 29 1/day, just barely above the minimal standards for private use in urban areas of 20 1/person/day. To further compound the problem, 20 villages in Zinder's environs, some villages with a population of 5000, people, rely on the same water system. Zinder serves as a refuge for the regional population in drought years and during the yearly dry season. Promised international financing cannot resolve Zinder's problems at a realistic cost.

  19. Local Control of Forest Floor Organic Layer (F and H Layers) Drying Processes

    NASA Astrophysics Data System (ADS)

    Keith, D. M.; Johnson, E. A.

    2008-12-01

    The forest floor in many ecosystems consists of a partially decomposed organic layer (duff). The duff, along with the litter layer, is the boundary between the atmosphere and the mineral soil, and for this reason it plays a crucial role in forest hydrology. The water budget of the duff is locally controlled throughout much of the snow free season, i.e. vertical fluxes dominate the water budget. During these dry periods the moisture content of the top layer of the duff, known as the F layer, cycles diurnally. Our objective is to better understand the processes controlling the duff water budget during dry periods using both modeling and field experiments. The model couples heat and mass transfer with meteorological fluxes to quantify the duff water budget during dry periods; since the fluxes are vertical during these dry periods the model is one dimensional. Field experiments determined which processes control the duff water budget during dry periods. The results indicate that the diurnal cycling of the moisture content in the F layer during dry periods is controlled by diurnal meteorological fluxes which drive coupled liquid and vapour fluxes through the duff layer. Additionally, there is minimal moisture movement between the mineral soil and the duff layer during these dry periods. This suggests that the duff water budget during dry periods is disconnected from the underlying mineral soil. The simulations incorporated the coupled meteorological fluxes and the disconnection between the duff and the mineral soil. These simulations reproduced the drying pattern in the duff with Nash-Sutcliffe efficiencies greater than 0.910 and coefficients of determination greater than 0.970 during the two longest precipitation free periods in the summer of 2007.

  20. Dry-cleaning of graphene

    SciTech Connect

    Algara-Siller, Gerardo; Lehtinen, Ossi; Kaiser, Ute; Turchanin, Andrey

    2014-04-14

    Studies of the structural and electronic properties of graphene in its pristine state are hindered by hydrocarbon contamination on the surfaces. Also, in many applications, contamination reduces the performance of graphene. Contamination is introduced during sample preparation and is adsorbed also directly from air. Here, we report on the development of a simple dry-cleaning method for producing large atomically clean areas in free-standing graphene. The cleanness of graphene is proven using aberration-corrected high-resolution transmission electron microscopy and electron spectroscopy.

  1. Accelerated Drying of Wet Boots

    DTIC Science & Technology

    2002-11-01

    ministre de la D6fense nationale, 2002 Abstract Much has been written about materials known as "super absorbers" with respect to their ability to keep...the skin dry in the presence of moisture. One such material is sodium polyacrylate. Because recent field trials with Canadian Forces soldiers have...l’efficacit6 de tampons de s6chage A base de polyacrylate de sodium pour s6cher les bottes de combat en conditions de campagne simul6es. La botte utilis6e pour

  2. Small polarons in dry DNA

    NASA Astrophysics Data System (ADS)

    Chacham, Helio; Alexandre, Simone S.; Soler, Jose M.; Artacho, Emilio

    2004-03-01

    The phenomenon of charge transport in DNA has been attracting attention of both biologists and physicists. From the biology side, there are evidences that charge injection can be associated to damage, mutation, and repair processes in DNA. From the physical sciences side, recent developments in nanotechnology now allow the measurement of currents through single DNA molecules in dried samples, which depict semiconductor behavior. Several mechanisms have been proposed for charge migration and transport in DNA. In that respect, detailed electrical transport measurements through DNA molecules containing identical base pairs (poly(dA)-poly(dT) and poly(dG)-poly(dC)) have been recently reported by Yoo et al [1]. These results fit extremely well a model in which the conduction is due to small polaron motion. In particular, these results indicate that the I-V characteristic of poly(dG)-poly(dC) DNA above 200 K is consistent with a small polaron hopping regime with an activation energy of 0.12 eV. In this work [2] we investigate the polaron formation in dry DNA by applying ab initio calculations to both neutral and charged fragments of dry poly(dG)-poly(dC). Our calculations show that the hole polaron in dry poly(dG)-poly(dC) DNA is a clear case of small polaron. This is verified by four basic properties: (i) the small variation of the polaron binding energy as a function of the DNA fragment size, for small fragment sizes, which is an indication of polaron localization; (ii) the fact that the width of the uppermost valence band is an order of magnitude smaller than the polaron binding energy; (iii) the explicit localization of the hole wavefunction for the largest considered fragment (four base pairs), indicated by the fact that about half of the norm of the hole is localized on a single guanine site; (iv) the localization of structural deformations at the nucleotides where the hole is concentrated. Our calculations also give a polaron binding energy of 0.30 eV. This allows

  3. Dry-Column Flash Chromatography

    NASA Astrophysics Data System (ADS)

    Shusterman, Alan J.; McDougal, Patrick G.; Glasfeld, Arthur

    1997-10-01

    Dry-column flash chromatography is a safe, powerful, yet easily learned preparative chromatography technique. It has proven useful in research, and an adaptation of the technique for use in large teaching laboratories (general chemistry, organic chemistry) is described here. The student version is similar to vacuum filtration, uses the same compact, readily available glassware, and inexpensive and safe solvents (ethyl acetate and hexane) and adsorbent (Merck grade 60 silica gel). The technique is sufficiently simple and powerful that a beginning student can successfully resolve diastereomers on sample scales ranging from 100 mg to >1 g.

  4. Drying and Quality Characteristics of Fresh and Sugar-infused Blueberries Dried with Infrared Radiation Heating

    USDA-ARS?s Scientific Manuscript database

    We evaluated the finished product quality and infrared (IR) drying characteristics of fresh and sugar-infused blueberries dried with a catalytic infrared (CIR) dryer. IR drying tests were conducted at four product temperatures (60, 70, 80, and 90oC) to evaluate the drying rate, and the color and te...

  5. Dry Transfer Systems for Used Nuclear Fuel

    SciTech Connect

    Brett W. Carlsen; Michaele BradyRaap

    2012-05-01

    The potential need for a dry transfer system (DTS) to enable retrieval of used nuclear fuel (UNF) for inspection or repackaging will increase as the duration and quantity of fuel in dry storage increases. This report explores the uses for a DTS, identifies associated general functional requirements, and reviews existing and proposed systems that currently perform dry fuel transfers. The focus of this paper is on the need for a DTS to enable transfer of bare fuel assemblies. Dry transfer systems for UNF canisters are currently available and in use for transferring loaded canisters between the drying station and storage and transportation casks.

  6. Experimental study of cassava sun drying

    SciTech Connect

    Njie, D.N.; Rumsey, T.R.

    1997-03-01

    Sun drying experiments were performed to compare drying of cassava chips in sheet-metal trays with drying on mesh wire trays. In the sheet-metal trays, there was air flow across the top of the bed chips, while the mesh wire trays permitted air to flow through the bed. Drying rate was faster and more uniform in the trays with through-flow air circulation. Higher temperatures were reached by chips in the sheet-metal trays than those in the mesh trays because of contact heating, but the drying rate was lower because of the reduced air flow.

  7. The Solar Cycle.

    PubMed

    Hathaway, David H

    The solar cycle is reviewed. The 11-year cycle of solar activity is characterized by the rise and fall in the numbers and surface area of sunspots. A number of other solar activity indicators also vary in association with the sunspots including; the 10.7 cm radio flux, the total solar irradiance, the magnetic field, flares and coronal mass ejections, geomagnetic activity, galactic cosmic ray fluxes, and radioisotopes in tree rings and ice cores. Individual solar cycles are characterized by their maxima and minima, cycle periods and amplitudes, cycle shape, the equatorward drift of the active latitudes, hemispheric asymmetries, and active longitudes. Cycle-to-cycle variability includes the Maunder Minimum, the Gleissberg Cycle, and the Gnevyshev-Ohl (even-odd) Rule. Short-term variability includes the 154-day periodicity, quasi-biennial variations, and double-peaked maxima. We conclude with an examination of prediction techniques for the solar cycle and a closer look at cycles 23 and 24. Supplementary material is available for this article at 10.1007/lrsp-2015-4.

  8. Dry eye after haematopoietic stem cell transplantation.

    PubMed

    Ogawa, Y; Okamoto, S; Wakui, M; Watanabe, R; Yamada, M; Yoshino, M; Ono, M; Yang, H Y; Mashima, Y; Oguchi, Y; Ikeda, Y; Tsubota, K

    1999-10-01

    To determine the incidence, natural course, and severity of dry eye occurring or worsening after haematopoietic stem cell transplantation (SCT). At a tertiary care hospital, 53 patients undergoing allogeneic or autologous SCT followed by at least 180 days of follow up were studied prospectively. Examination included grading of symptoms of dry eye, evaluation of ocular surface, tear break up time, and Schirmer tests with and without nasal stimulation. Meibomian gland secretion was also examined using a slit lamp while applying steady digital pressure. Of the 53 patients, 44 received allografts. Half of these patients (22) developed dry eye or their pre-existing dry eye worsened after SCT, while none of nine autograft recipients did. Onset of dry eye was 171 (SD 59) days after SCT. Two types of dry eye occurred. One (n=10) was severe with ocular surface findings resembling Sjögren's syndrome and reduction of reflex tearing soon after onset. A mild type (n=12) had unimpaired reflex tearing. Meibomian gland dysfunction (MGD) was more frequent and severe in patients with dry eye and chronic graft versus host disease (GVHD), and overall severity of dry eye was greater in patients with MGD and chronic GVHD. Dry eye after SCT occurred only in allograft recipients, and was not evident in autograft recipients. The severe form of dry eye had a tendency to develop rapidly. Further study on the prediction and treatment of severe dry eye after SCT is necessary.

  9. Atmospheric freeze drying assisted by power ultrasound

    NASA Astrophysics Data System (ADS)

    Santacatalina, J. V.; Cárcel, J. A.; Simal, S.; Garcia-Perez, J. V.; Mulet, A.

    2012-12-01

    Atmospheric freeze drying (AFD) is considered an alternative to vacuum freeze drying to keep the quality of fresh product. AFD allows continuous drying reducing fix and operating costs, but presents, as main disadvantage, a long drying time required. The application of power ultrasound (US) can accelerate AFD process. The main objective of the present study was to evaluate the application of power ultrasound to improve atmospheric freeze drying of carrot. For that purpose, AFD experiments were carried out with carrot cubes (10 mm side) at constant air velocity (2 ms-1), temperature (-10°C) and relative humidity (10%) with (20.5 kWm-3,USAFD) and without (AFD) ultrasonic application. A diffusion model was used in order to quantify the influence of US in drying kinetics. To evaluate the quality of dry products, rehydration capacity and textural properties were determined. The US application during AFD of carrot involved the increase of drying rate. The effective moisture diffusivity identified in USAFD was 73% higher than in AFD experiments. On the other hand, the rehydration capacity was higher in USAFD than in AFD and the hardness of dried samples did not show significant (p<0.05) differences. Therefore, US application during AFD significantly (p<0.05) sped-up the drying process preserving the quality properties of the dry product.

  10. Dry spell frequency in West Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Purnaningtyas, V. I.; Boer, R.; Faqih, A.

    2017-03-01

    The climatology and variability of dry spells are valuable information for scientists, engineers, planners, and managers working in water-related sectors such as agriculture, ecology, hydrology, and water resources. The dry spell concerns consecutive dry days which are the largest number of consecutive days with less than 1 mm of daily precipitation within a year. The objective of this study is to analyse the spatial and temporal characteristics of dry spells and also specifically investigate the frequency patterns of the dry spell distribution based on historical observed daily precipitation from 1981 to 2010. The longest dry spell occured at Pasirukem with the length of 252 days. The northern coast of West Java have higher probabilities of dry spells more than 5, 10, 15, and 20 days.

  11. Drying of solids in fluidized beds

    SciTech Connect

    Kannan, C.S.; Thomas, P.P.; Varma, Y.B.G.

    1995-09-01

    Fluidized bed drying is advantageously adopted in industrial practice for drying of granular solids such as grains, fertilizers, chemicals, and minerals either for long shelf life or to facilitate further processing or handling. Solids are dried in batch and in continuous fluidized beds corresponding to cross-flow and countercurrent flow of phases covering a wide range in drying conditions. Materials that essentially dry with constant drying rate and then give a falling drying rate approximately linear with respect to solids moisture content (sand) as well as those with an extensive falling rate period with the subsequent falling rate being a curve with respect to the moisture content (mustard, ragi, poppy seeds) are chosen for the study. The performance of the continuous fluidized bed driers is compared with that of batch fluidized bed driers; the performance is predicted using batch kinetics, the residence time distribution of solids, and the contact efficiency between the phases.

  12. Intermittent pool beds are permanent cyclic habitats with distinct wet, moist and dry phases.

    PubMed

    Dell, Anthony I; Alford, Ross A; Pearson, Richard G

    2014-01-01

    Recognition that intermittent pools are a single habitat phase of an intermittent pool bed that cycles between aquatic and terrestrial habitat greatly enhances their usefulness for addressing general questions in ecology. The aquatic phase has served as a model system in many ecological studies, because it has distinct habitat boundaries in space and time and is an excellent experimental system, but the aquatic to terrestrial transition and terrestrial phase remain largely unstudied. We conducted a field experiment within six replicate natural intermittent pool beds to explore macroinvertebrate community dynamics during the transition from aquatic to terrestrial habitat and during the terrestrial phase. We monitored and compared macroinvertebrate communities within leaf packs that i) remained wet, ii) underwent drying (i.e., started wet and then dried), and iii) remained dry. Our results show that i) a diverse macroinvertebrate community inhabits all phases of intermittent pool beds, ii) pool drying involves colonization by an assemblage of macroinvertebrates not recorded in permanently terrestrial leaf packs, iii) the community within dried leaf packs remains distinct from that of permanently terrestrial leaf packs for an extended period following drying (possibly until subsequent refilling), and iv) there are likely to be strong spatial and temporal resource linkages between the aquatic and terrestrial communities. The unique environmental characteristics of intermittent pool beds, which repeatedly cycle from aquatic to terrestrial habitat, should continue to make them valuable study systems.

  13. Sludge-Drying Lagoons: a Potential Significant Methane Source in Wastewater Treatment Plants.

    PubMed

    Pan, Yuting; Ye, Liu; van den Akker, Ben; Ganigué Pagès, Ramon; Musenze, Ronald S; Yuan, Zhiguo

    2016-02-02

    "Sludge-drying lagoons" are a preferred sludge treatment and drying method in tropical and subtropical areas due to the low construction and operational costs. However, this method may be a potential significant source of methane (CH4) because some of the organic matter would be microbially metabolized under anaerobic conditions in the lagoon. The quantification of CH4 emissions from lagoons is difficult due to the expected temporal and spatial variations over a lagoon maturing cycle of several years. Sporadic ebullition of CH4, which cannot be easily quantified by conventional methods such as floating hoods, is also expected. In this study, a novel method based on mass balances was developed to estimate the CH4 emissions and was applied to a full-scale sludge-drying lagoon over a three year operational cycle. The results revealed that processes in a sludge-drying lagoon would emit 6.5 kg CO2-e per megaliter of treated sewage. This would represent a quarter to two-thirds of the overall greenhouse gas (GHG) emissions from wastewater-treatment plants (WWTPs). This work highlights the fact that sludge-drying lagoons are a significant source of CH4 that adds substantially to the overall GHG footprint of WWTPs despite being recognized as a cheap and energy-efficient means of drying sludge.

  14. Increasing contrasts between wet and dry precipitation extremes during the "global warming hiatus" (1998-2013)

    NASA Astrophysics Data System (ADS)

    Lau, W. K. M.; Wu, H. T.

    2015-12-01

    We investigate changes in daily precipitation extremes using TRMM data (1998-2013), which coincides with the so-called "global warming hiatus". Results show a structural change in probability distribution functions (pdf) of local precipitation events (LPE) during this period, indicating more intense LPE, less moderate LPE, and more dry (no-rain) days globally. Analyses for land and ocean separately reveal more complex and nuanced changes over land, characterized by a strong positive trend (+12.0% per decade, 99% confidence level (c.l.)) in frequency of extreme LPE's over the Northern Hemisphere extratropics during the wet season, but a negative global trend (-6.6% per decade, 95% c.l.) during the dry season. Analyses of the risk of drought based on the number of dry days show a significant global drying trend (3.2% per decade, 99% c.l.) over land during the dry season. Regions of pronounced increased drought include western and central US, northeastern Asia and southern Europe/Mediterranean. Trends in cloud distributions from TRMM VIS-IR, and relative humidity from reanalysis have also been examined. Overall, the changes in water cycle parameters are consistent with increasing contrasts between wet and dry precipitation extremes, as reported in previous studies based on observations and climate model projections for a longer period, implying changes in global water cycle was underway during 1998-2013 as if there is no "global warming hiatus". The implications of the present results will be discussed.

  15. Intermittent Pool Beds Are Permanent Cyclic Habitats with Distinct Wet, Moist and Dry Phases

    PubMed Central

    Dell, Anthony I.; Alford, Ross A.; Pearson, Richard G.

    2014-01-01

    Recognition that intermittent pools are a single habitat phase of an intermittent pool bed that cycles between aquatic and terrestrial habitat greatly enhances their usefulness for addressing general questions in ecology. The aquatic phase has served as a model system in many ecological studies, because it has distinct habitat boundaries in space and time and is an excellent experimental system, but the aquatic to terrestrial transition and terrestrial phase remain largely unstudied. We conducted a field experiment within six replicate natural intermittent pool beds to explore macroinvertebrate community dynamics during the transition from aquatic to terrestrial habitat and during the terrestrial phase. We monitored and compared macroinvertebrate communities within leaf packs that i) remained wet, ii) underwent drying (i.e., started wet and then dried), and iii) remained dry. Our results show that i) a diverse macroinvertebrate community inhabits all phases of intermittent pool beds, ii) pool drying involves colonization by an assemblage of macroinvertebrates not recorded in permanently terrestrial leaf packs, iii) the community within dried leaf packs remains distinct from that of permanently terrestrial leaf packs for an extended period following drying (possibly until subsequent refilling), and iv) there are likely to be strong spatial and temporal resource linkages between the aquatic and terrestrial communities. The unique environmental characteristics of intermittent pool beds, which repeatedly cycle from aquatic to terrestrial habitat, should continue to make them valuable study systems. PMID:25244550

  16. DRY DEPOSITION OF REDUCED AND REACTIVE NITROGEN: A SURROGATE SURFACES APPROACH. (R826647)

    EPA Science Inventory

    Nitrogen dry deposition causes pH modification of ecosystems, promotes
    eutrophication in some water bodies, interferes with the nutrient geochemical
    cycle on land, and has a deteriorating effect on buildings. In this study, a
    water surface sampler (WSS) and knife-l...

  17. [Microbial response mechanism for drying and rewetting effect on soil respiration in grassland ecosystem: a review].

    PubMed

    He, Yun-Long; Qi, Yu-Chun; Dong, Yun-She; Peng, Qin; Sun, Liang-Jie; Jia, Jun-Qiang; Guo, Shu-Fang; Yan, Zhong-Qing

    2014-11-01

    As one of the most important and wide distribution community type among terrestrial ecosystems, grassland ecosystem plays a critical role in the global carbon cycles and climate regulation. China has extremely rich grassland resources, which have a huge carbon sequestration potential and are an important part of the global carbon cycle. Drying and rewetting is a common natural phenomenon in soil, which might accelerate soil carbon mineralization process, increase soil respiration and exert profound influence on microbial activity and community structure. Under the background of the global change, the changes in rainfall capacity, strength and frequency would inevitably affect soil drying and wetting cycles, and thus change the microbial activity and community structure as well as soil respiration, and then exert important influence on global carbon budget. In this paper, related references in recent ten years were reviewed. The source of soil released, the trend of soil respiration over time and the relationship between soil respiration and microbial biomass, microbial activity and microbial community structure during the processes of dry-rewetting cycle were analyzed and summarized, in order to better understand the microbial response mechanism for drying and rewetting effecting on soil respiration in grassland ecosystem, and provide a certain theoretical basis for more accurate evaluation and prediction of future global carbon balance of terrestrial ecosystems and climate change.

  18. Compressive mechanical properties of porous GO materials prepared from freeze-drying method

    NASA Astrophysics Data System (ADS)

    Chen, Hui; Li, Zheng; Liu, Xing; Ren, Hu-Ming; Tang, Xian-Qiong; Zhang, Ping; Ding, Yan-Huai

    2017-02-01

    In this paper porous graphene oxide (GO) foams were prepared from freeze-drying method. Compressive mechanical properties of GO foams with different density were investigated by uniaxial compression experiments and finite element (FE) simulation. GO foam exhibited excellent elasticity, which recovered to its original length even after 300 cycles. The structural evolution during the compression was revealed by FE simulation.

  19. DRY DEPOSITION OF REDUCED AND REACTIVE NITROGEN: A SURROGATE SURFACES APPROACH. (R826647)

    EPA Science Inventory

    Nitrogen dry deposition causes pH modification of ecosystems, promotes
    eutrophication in some water bodies, interferes with the nutrient geochemical
    cycle on land, and has a deteriorating effect on buildings. In this study, a
    water surface sampler (WSS) and knife-l...

  20. Dry borax applicator operator's manual.

    SciTech Connect

    Karsky, Richard, J.

    1999-01-01

    Annosum root rot affects conifers throughout the Northern Hemisphere, infecting their roots and eventually killing the trees. The fungus Heterobasidion annosum causes annosum root rot. The fungus colonizes readily on freshly cut stumps. Partially cut stands have a high risk of infestation because the fungus can colonize on each of the stumps and potentially infect the neighboring trees. Wind and rain carry the annosum spores. Spores that land on freshly cut stumps grow down the stump's root system where they can infect living trees through root grafts or root contacts. Once annosum becomes established, it can remain active for many years in the Southern United States and for several decades in the north. About 7% of the trees that become infected die. When thinning, stumps can be treated successfully using a competing fungus, Phlebia gigantea, and with ''Tim-Bor'' in liquid formulations. These liquid products are no longer approved in the United States. Only the dry powder form is registered and approved by the EPA. Stumps can be treated with a dry formula of borax, (Sporax), significantly reducing one of the primary routes by which Heterobasidion annosum infects a stand of trees. Sporax is used by the USDA Forest Service to control annosum root rot. Sporax is now applied by hand, but once the felled trees are skidded it becomes very hard to locate the stumps. A stump applicator will reduce error, labor costs, and hazards to workers.

  1. Cocoon drying through solar energy

    SciTech Connect

    Kulunk, M.

    1983-12-01

    In this paper, silk cocoon drying operations through solar energy have been presented. Nearly no comprehensive work has been appeared in literature on this unusual application. General mechanism of solar drying methods are presented by some authors for instance, Roman and Jindal. This application seems vitally significant for silk cocoon producer countries like Turkey. The rate of production accelerates year by year and it is about 3000 tons per year presently in Turkey. In Turkey, by now and currently, a water vapour chamber is utilized in the killing process of silkworm. Vapour produced by burning of conventional fuels posses many drawbacks beside being very expensive and also non-renewable. Vapour effects the quality and quantity of silk thread negatively. For instance, the colour of silk cocoon tends to turn to pale instead of being gleamy. This is not tolerable. The length and mass of silk thread obtained per a typical cocoon sample is increased about 10.1 and 16.5 per cent respectively in the average by using solar energy.

  2. Effect of Extreme Drought on Tropical Dry Forests

    NASA Astrophysics Data System (ADS)

    Castro, Saulo; Sanchez-Azofeifa, Arturo; Sato, Hiromitsu; Cowling, Sharon; Vega-Araya, Mauricio

    2017-04-01

    Tropical dry forests (TDFs) hold a strong economic and cultural connection to human development in the Neotropics. Historically, TDFs not only represent a source of agricultural and urban land but also an important source of goods and ecosystem services for the communities that live around them. Such is the close connection of TDFs to human activity that they are considered the most heavily utilized and disturbed ecosystem in the world. However, TDF have been largely understudied and represent only a fraction of research devoted to globally tropical ecosystems. Thus we lack the framework to properly project how predicted increases in drought events due to climate change will impact TDFs and human society which depend on its services. Our study aims to show the effect of extreme drought on water, food security, and tropical dry forest productivity in the Guanacaste province of Costa Rica. Two pre-ENSO years (2013-2014) and an ENSO year (2015) were compared. The 2013 and 2014 pre-ENSO years were classified as a normal precipitation (1470 mm) and drought year (1027mm), respectively. The 2015 ENSO year was classified as a severe drought (654mm), with amplified effects resulting by the drought experienced during the previous (2014) growing cycle. Effects of the ENSO drought on agriculture and livestock sectors in the province included losses of US13million and US6.5million, respectively. Crop land losses equaled 2,118 hectares and 11,718 hectares were affected. Hydroelectricity generation decreased by 10% and potable water shortages were observed. The Agriculture and Livestock Ministry (MAG) and the National Emergency Commission (CNE) distributed animal feed and supplies to 4,000 farmers affected by the extreme droughts. Eddy covariance flux measurements were used to identify productivity changes during the extreme drought. Changes in phenologic stages and the transitions between CO2 sink to source during mid-growing cycle were observed. Drought significantly delayed

  3. Comparing the Life Cycle Energy Consumption, Global ...

    EPA Pesticide Factsheets

    Managing the water-energy-nutrient nexus for the built environment requires, in part, a full system analysis of energy consumption, global warming and eutrophication potentials of municipal water services. As an example, we evaluated the life cycle energy use, greenhouse gas (GHG) emissions and aqueous nutrient releases of the whole anthropogenic municipal water cycle starting from raw water extraction to wastewater treatment and reuse/discharge for five municipal water and wastewater systems. The assessed options included conventional centralized services and four alternative options following the principles of source-separation and water fit-for-purpose. The comparative life cycle assessment identified that centralized drinking water supply coupled with blackwater energy recovery and on-site greywater treatment and reuse was the most energyand carbon-efficient water service system evaluated, while the conventional (drinking water and sewerage) centralized system ranked as the most energy- and carbon-intensive system. The electricity generated from blackwater and food residuals co-digestion was estimated to offset at least 40% of life cycle energy consumption for water/waste services. The dry composting toilet option demonstrated the lowest life cycle eutrophication potential. The nutrients in wastewater effluent are the dominating contributors for the eutrophication potential for the assessed system configurations. Among the parameters for which variability

  4. Comparing the Life Cycle Energy Consumption, Global ...

    EPA Pesticide Factsheets

    Managing the water-energy-nutrient nexus for the built environment requires, in part, a full system analysis of energy consumption, global warming and eutrophication potentials of municipal water services. As an example, we evaluated the life cycle energy use, greenhouse gas (GHG) emissions and aqueous nutrient releases of the whole anthropogenic municipal water cycle starting from raw water extraction to wastewater treatment and reuse/discharge for five municipal water and wastewater systems. The assessed options included conventional centralized services and four alternative options following the principles of source-separation and water fit-for-purpose. The comparative life cycle assessment identified that centralized drinking water supply coupled with blackwater energy recovery and on-site greywater treatment and reuse was the most energyand carbon-efficient water service system evaluated, while the conventional (drinking water and sewerage) centralized system ranked as the most energy- and carbon-intensive system. The electricity generated from blackwater and food residuals co-digestion was estimated to offset at least 40% of life cycle energy consumption for water/waste services. The dry composting toilet option demonstrated the lowest life cycle eutrophication potential. The nutrients in wastewater effluent are the dominating contributors for the eutrophication potential for the assessed system configurations. Among the parameters for which variability

  5. Oscillations in land surface hydrological cycle

    NASA Astrophysics Data System (ADS)

    Labat, D.

    2006-02-01

    Hydrological cycle is the perpetual movement of water throughout the various component of the global Earth's system. Focusing on the land surface component of this cycle, the determination of the succession of dry and humid periods is of high importance with respect to water resources management but also with respect to global geochemical cycles. This knowledge requires a specified estimation of recent fluctuations of the land surface cycle at continental and global scales. Our approach leans towards a new estimation of freshwater discharge to oceans from 1875 to 1994 as recently proposed by Labat et al. [Labat, D., Goddéris, Y., Probst, JL, Guyot, JL, 2004. Evidence for global runoff increase related to climate warming. Advances in Water Resources, 631-642]. Wavelet analyses of the annual freshwater discharge time series reveal an intermittent multiannual variability (4- to 8-y, 14- to 16-y and 20- to 25-y fluctuations) and a persistent multidecadal 30- to 40-y variability. Continent by continent, reasonable relationships between land-water cycle oscillations and climate forcing (such as ENSO, NAO or sea surface temperature) are proposed even though if such relationships or correlations remain very complex. The high intermittency of interannual oscillations and the existence of persistent multidecadal fluctuations make prediction difficult for medium-term variability of droughts and high-flows, but lead to a more optimistic diagnostic for long-term fluctuations prediction.

  6. New approaches and potential treatments for dry age-related macular degeneration.

    PubMed

    Damico, Francisco Max; Gasparin, Fabio; Scolari, Mariana Ramos; Pedral, Lycia Sampaio; Takahashi, Beatriz Sayuri

    2012-01-01

    Emerging treatments for dry age-related macular degeneration (AMD) and geographic atrophy focus on two strategies that target components involved in physiopathological pathways: prevention of photoreceptors and retinal pigment epithelium loss (neuroprotection induction, oxidative damage prevention, and visual cycle modification) and suppression of inflammation. Neuroprotective drugs, such as ciliary neurotrophic factor, brimonidine tartrate, tandospirone, and anti-amyloid β antibodies, aim to prevent apoptosis of retinal cells. Oxidative stress and depletion of essential micronutrients are targeted by the Age-Related Eye Disease Study (AREDS) formulation. Visual cycle modulators reduce the activity of the photoreceptors and retinal accumulation of toxic fluorophores and lipofuscin. Eyes with dry age-related macular degeneration present chronic inflammation and potential treatments include corticosteroid and complement inhibition. We review the current concepts and rationale of dry age-related macular degeneration treatment that will most likely include a combination of drugs targeting different pathways involved in the development and progression of age-related macular degeneration.

  7. Explore the influence of agglomeration on electrochemical performance of an amorphous MnO2/C composite by controlling drying process

    NASA Astrophysics Data System (ADS)

    Cui, Mangwei; Kang, Litao; Shi, Mingjie; Xie, Lingli; Wang, Xiaomin; Zhao, Zhe; Yun, Shan; Liang, Wei

    2017-09-01

    Amorphous MnO2/C composite is prepared by a facile redox reaction between potassium permanganate (KMnO4) and commercial black pen ink. Afterwards, two different drying processes, air drying or freeze drying, are employed to adjust the agglomeration state of particles in samples and explore its influence on capacitive performance. Experimental results indicate that the air-dried sample demonstrates much better cycling stability than the freeze-dried one (capacity retention at 5000 cycles: 70.9 vs. 60.7%), probably because of the relatively strong agglomeration between particles in this sample. Nevertheless, strong agglomeration seems to deteriorate the specific capacitance (from 492 down to 440.5 F/g at 1 A/g) due to the decrease of porosity and specific surface area. This study suggests that agglomeration of primary particles plays an important role to balance the specific capacitance and cycling stability for electrode materials.

  8. Low cycle fatigue

    NASA Technical Reports Server (NTRS)

    Solomon, H. D. (Editor); Kaisand, L. R. (Editor); Halford, G. R. (Editor); Leis, B. N. (Editor)

    1988-01-01

    The papers contained in this volume focus on various aspects of low cycle fatigue, including cyclic deformation, crack propagation, high-temperature low cycle fatigue, microstructural defects, multiaxial and variable amplitude loading, and life prediction. Papers are presented on the low cycle fatigue of some aluminum alloys, prediction of crack growth under creep-fatigue loading conditions, high-temperature low cycle fatigue behavior and lifetime prediction of a nickel-base ODS alloy, and an integrated approach to creep-fatigue life prediction. Other topics discussed include thermal fatigue testing of coated monocrystalline superalloys, low cycle fatigue of Al-Mg-Si alloys, and the effect of superimposed stresses at high frequency on low cycle fatigue.

  9. Low cycle fatigue

    NASA Technical Reports Server (NTRS)

    Solomon, H. D. (Editor); Kaisand, L. R. (Editor); Halford, G. R. (Editor); Leis, B. N. (Editor)

    1988-01-01

    The papers contained in this volume focus on various aspects of low cycle fatigue, including cyclic deformation, crack propagation, high-temperature low cycle fatigue, microstructural defects, multiaxial and variable amplitude loading, and life prediction. Papers are presented on the low cycle fatigue of some aluminum alloys, prediction of crack growth under creep-fatigue loading conditions, high-temperature low cycle fatigue behavior and lifetime prediction of a nickel-base ODS alloy, and an integrated approach to creep-fatigue life prediction. Other topics discussed include thermal fatigue testing of coated monocrystalline superalloys, low cycle fatigue of Al-Mg-Si alloys, and the effect of superimposed stresses at high frequency on low cycle fatigue.

  10. Vuilleumier Cycle Cryogenic Refrigeration

    DTIC Science & Technology

    1976-04-01

    WORDS (Continue on reverse side if necessary and identify by block number) Cryogenic Refrigerator Vuilleumier Cycle 20. ABSTRACT (Continue on reverse ...The energy added to the gas was stored in the regenerator packing, or matrix, by gas flow in the reverse direction during a previous part of the cycle ...AFFDL-TR-76-17 VUILLEUMIER CYCLE CRYOGENIC REFRIGERATION ENVIRONMENTAL CONTROL BRANCH 4 VEHICLE EQUIPMENT DIVISION APRIL 1976 TECHNICAL REPORT AFFDL

  11. Simultaneously cycled NMR spectroscopy.

    PubMed

    Parish, David M; Szyperski, Thomas

    2008-04-09

    Simultaneously cycled (SC) NMR was introduced and exemplified by implementing a set of 2-D [1H,1H] SC exclusive COSY (E.COSY) NMR experiments, that is, rf pulse flip-angle cycled (SFC), rf pulse phase cycled (SPC), and pulsed field gradient (PFG) strength cycled (SGC) E.COSY. Spatially selective 1H rf pulses were applied as composite pulses such that all steps of the respective cycles were affected simultaneously in different slices of the sample. This increased the data acquisition speed for an n-step cycle n-fold. A high intrinsic sensitivity was achieved by defining the cycles in a manner that the receiver phase remains constant for all steps of the cycle. Then, the signal resulting from applying the cycle corresponded to the sum of the signals from all steps of the cycle. Hence, the detected free induction decay did not have to be separated into the contributions arising from different slices, and read-out PFGs, which not only greatly reduce sensitivity but also negatively impact lineshapes in the direct dimension, were avoided. The current implementation of SFC E.COSY reached approximately 65% of the intrinsic sensitivity of the conventional phase cycled congener, making this experiment highly attractive whenever conventional data acquisition is sampling limited. Highly resolved SC E.COSY yielding accurate 3J-coupling values was recorded for the 416 Da plant alkaloid tomatidine within 80 min, that is, 12 times faster than with conventional phase cycled E.COSY. SC NMR is applicable for a large variety of NMR experiments and thus promises to be a valuable addition to the arsenal of approaches for tackling the NMR sampling problem to avoid sampling limited data acquisition.

  12. [Cycling in Zagreb].

    PubMed

    Matos, Stipan; Krapac, Ladislav; Krapac, Josip

    2007-01-01

    Cycling in Zagreb, as means of urban transport inside and outside the city, has a bright past, hazy presence but a promising future. Every day, aggressive citizens who lack urban traffic culture mistreat many cyclists but also many pedestrians. Sedentary way of living, unhealthy eating habits and inadequate recreation would surely be reduced if Zagreb had a network of cycling tracks (190 cm) or lanes (80 cm). Main city roads were constructed at the beginning of the 20th century. Today, the lack of cycling tracks is particularly evident in terms of missing connections between northern and southern parts of the city. Transportation of bikes in public vehicles, parking of bikes as well as cycling along the foot of the mountains Medvednica and Zumberacko gorje is not adequately organized. Better organization is necessary not only because of the present young generation but also because of the young who will shortly become citizens of the EU, where cycling is enormously popular. Cycling tourism is not known in Zagreb, partly due to inadequate roads. The surroundings of Zagreb are more suitable for cycling tourism and attractive brochures and tourist guides offer information to tourists on bikes. Professional, acrobatic and sports cycling do not have a tradition in Zagreb and in Croatia. The same holds true for recreational cycling and indoor exercise cycling. The authors discuss the impact of popularization of cycling using print and electronic media. The role of district and local self-government in the construction and improvement of traffic roads in Zagreb is very important. It is also significant for the implementation of legal regulations that must be obeyed by all traffic participants in order to protect cyclists, the most vulnerable group of traffic participants besides passengers. Multidisciplinary action of all benevolent experts would surely increase safety and pleasure of cycling in the city and its surroundings. This would also help reduce daily stress and

  13. Dry Valley streams in Antarctica: Ecosystems waiting for water

    USGS Publications Warehouse

    McKnight, Diane M.; Niyogi, D.K.; Alger, A.S.; Bomblies, A.; Conovitz, P.A.; Tate, C.M.

    1999-01-01

    effects of reintroducing water flow to channels in which flow has not occurred for decades or centuries. The present work of the McMurdo Dry Valleys LTER has led us to conclude that the legacy of past conditions constitutes a dominant influence on present-day ecosystem structure and function in the dry valleys (Moorhead et al. 1999). For example, Virginia-and Wall (1999) have found that soil nematodes are partly sustained by relict organic carbon from algae that grew during the high lake stands of 8000-10,000 years ago. Similarly, the growth of current algal populations in the lakes of the dry valleys is supported by diffusion of nutrients from relict nutrient pools in the deep bottom waters (Priscu et al. 1999). For the stream ecosystems, abundant algal mats are present in channels that have stable stone pavements, which formed through freeze-thaw cycles occurring over long periods, possibly hundreds of years. We hypothesize that these stone pavements are an important ecological legacy permitting the successful 'waiting for water' strategy. Similarly, the biodiversity of algal species that can survive the harsh conditions in the streams of the dry valleys may be stable for centuries or more, representing a second important ecological legacy.

  14. Kilogram-scale production of SnO(2) yolk-shell powders by a spray-drying process using dextrin as carbon source and drying additive.

    PubMed

    Choi, Seung Ho; Kang, Yun Chan

    2014-05-05

    A simple and general method for the large-scale production of yolk-shell powders with various compositions by a spray-drying process is reported. Metal salt/dextrin composite powders with a spherical and dense structure were obtained by spray drying and transformed into yolk-shell powders by simple combustion in air. Dextrin plays a key role in the preparation of precursor powders for fabricating yolk-shell powders by spray drying. Droplets containing metal salts and dextrin show good drying characteristics even in a severe environment of high humidity. Sucrose, glucose, and polyvinylpyrrolidone are widely used as carbon sources in the preparation of metal oxide/carbon composite powders; however, they are not appropriate for large-scale spray-drying processes because of their caramelization properties and adherence to the surface of the spray dryer. SnO2 yolk-shell powders were studied as the first target material in the spray-drying process. Combustion of tin oxalate/dextrin composite powders at 600 °C in air produced single-shelled SnO2 yolk-shell powders with the configuration SnO2 @void@SnO2 . The SnO2 yolk-shell powders prepared by the simple spray-drying process showed superior electrochemical properties, even at high current densities. The discharge capacities of the SnO2 yolk-shell powders at a current density of 2000 mA g(-1) were 645 and 570 mA h g(-1) for the second and 100th cycles, respectively; the corresponding capacity retention measured for the second cycle was 88 %. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Influence of ethanol on physical state of freeze-dried mannitol.

    PubMed

    Takada, Akira; Nail, Steven L; Yonese, Masakatsu

    2009-05-01

    The purpose of this study is to characterize freeze-dried mannitol prepared from an ethanol-containing solution as a function of the ethanol ratio, mannitol concentration, and annealing in the freeze-drying cycle. The characteristics of the freeze-dried mannitol were evaluated by X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The reconstitution time was measured for the freeze-dried solids as well as the residual moisture and ethanol by Karl-Fischer titration and gas chromatography, respectively. The XRD pattern of 5% (w/v) mannitol freeze-dried from aqueous solution with no annealing cycle showed all the five characteristic peaks at 13.6 degrees and 17.2 degrees 2theta for the alpha polymorph, at 14.6 degrees and 23.4 degrees 2theta for the beta polymorph and at 9.7 degrees 2theta for the delta polymorph. The addition of ethanol to the initial solutions resulted in only a peak at 9.7 degrees 2theta, indicating the presence of only the delta polymorph, regardless of the ethanol ratio in the initial solutions used [10, 20, 30, and 40% (v/v)]. However, annealing during freeze-drying influenced the XRD pattern; in particular, for the solid prepared from the 10% ethanol solution. Annealing of the 10% ethanol solution promoted the formation of the alpha polymorph and produced a different peak that might be attributable to another polymorph. In DSC thermograms, an endotherm and a subsequent exotherm were found in the temperature range of 150 degrees C to 160 degrees C, which corresponded to the transition of the delta form to alpha or beta forms. The magnitude of this transition was smaller as the ethanol ratio increased for the solids from ethanol-containing solutions with an annealing cycle. In other words, annealing of the ethanol-containing solutions promoted delta polymorph formation in the lyophiles. In addition, the mannitol concentration affected the polymorphism in freeze-dried solids prepared from aqueous and 10% ethanol solutions

  16. CO2 (dry ice) cleaning system

    NASA Astrophysics Data System (ADS)

    Barnett, Donald M.

    1995-03-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system

  17. CO2 (dry ice) cleaning system

    NASA Technical Reports Server (NTRS)

    Barnett, Donald M.

    1995-01-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system

  18. Biomass drying in a pulsed fluidized bed without inert bed particles

    SciTech Connect

    Jia, Dening; Bi, Xiaotao; Lim, C. Jim; Sokhansanj, Shahab; Tsutsumi, Atsushi

    2016-08-29

    Batch drying was performed in the pulsed fluidized bed with various species of biomass particles as an indicator of gas–solid contact efficiency and mass transfer rate under different operating conditions including pulsation duty cycle and particle size distribution. The fluidization of cohesive biomass particles benefited from the shorter opening time of pulsed gas flow and increased peak pressure drop. The presence of fines enhanced gas–solid contact of large and irregular biomass particles, as well as the mass transfer efficiency. A drying model based on two-phase theory was proposed, from which effective diffusivity was calculated for various gas flow rates, temperature and pulsation frequency. Intricate relationship was discovered between pulsation frequency and effective diffusivity, as mass transfer was deeply connected with the hydrodynamics. Effective diffusivity was also found to be proportional to gas flow rate and drying temperature. In conclusion, operating near the natural frequency of the system also favored drying and mass transfer.

  19. Biomass drying in a pulsed fluidized bed without inert bed particles

    SciTech Connect

    Jia, Dening; Bi, Xiaotao; Lim, C. Jim; Sokhansanj, Shahab; Tsutsumi, Atsushi

    2016-08-29

    Batch drying was performed in the pulsed fluidized bed with various species of biomass particles as an indicator of gas–solid contact efficiency and mass transfer rate under different operating conditions including pulsation duty cycle and particle size distribution. The fluidization of cohesive biomass particles benefited from the shorter opening time of pulsed gas flow and increased peak pressure drop. The presence of fines enhanced gas–solid contact of large and irregular biomass particles, as well as the mass transfer efficiency. A drying model based on two-phase theory was proposed, from which effective diffusivity was calculated for various gas flow rates, temperature and pulsation frequency. Intricate relationship was discovered between pulsation frequency and effective diffusivity, as mass transfer was deeply connected with the hydrodynamics. Effective diffusivity was also found to be proportional to gas flow rate and drying temperature. In conclusion, operating near the natural frequency of the system also favored drying and mass transfer.

  20. Dry holes of Georges Bank

    SciTech Connect

    Bailey, D.M.

    1982-11-01

    After winning the controversial Georges Bank debate, five oil companies have found only commercially unprofitable dry holes, which experts predict will become anywhere from marginal to vital in future years. The economic boom that offshore drilling was to bring to New England has not materialized despite rumors that the companies found either oil or gas that they are not yet ready to announce. Bad weather and the high cost of offshore drilling may be more responsible for the removal of drilling rigs from the area, but an industry-wide survey finds that only 2200 of 4800 offshore rigs are currently operating. Debate over Georges Bank focused on possible damage to the fishing industry and the windfall the government will receive if leasing is accelerated. Many expect to see rigs returning to Georges Bank in the spring. (DCK)

  1. Dry fermentation of agricultural residues

    NASA Astrophysics Data System (ADS)

    Jewell, W. J.; Chandler, J. A.; Dellorto, S.; Fanfoni, K. J.; Fast, S.; Jackson, D.; Kabrick, R. M.

    1981-09-01

    A dry fermentation process is discussed which converts agricultural residues to methane, using the residues in their as produced state. The process appears to simplify and enhance the possibilities for using crop residues as an energy source. The major process variables investigated include temperature, the amount and type of inoculum, buffer requirements, compaction, and pretreatment to control the initial available organic components that create pH problems. A pilot-scale reactor operation on corn stover at a temperature of 550 C, with 25 percent initial total solids, a seed-to-feed ratio of 2.5 percent, and a buffer-to-feed ratio of 8 percent achieved 33 percent total volatile solids destruction in 60 days. Volumetric biogas yields from this unit were greater than 1 vol/vol day for 12 days, and greater than 0.5 vol/vol day for 32 days, at a substrate density of 169 kg/m (3).

  2. Wetter for fine dry powder

    DOEpatents

    Hall, James E.; Williams, Everett H.

    1977-01-01

    A system for wetting fine dry powders such as bentonite clay with water or other liquids is described. The system includes a wetting tank for receiving water and a continuous flow of fine powder feed. The wetting tank has a generally square horizontal cross section with a bottom end closure in the shape of an inverted pyramid. Positioned centrally within the wetting tank is a flow control cylinder which is supported from the walls of the wetting tank by means of radially extending inclined baffles. A variable speed motor drives a first larger propeller positioned immediately below the flow control cylinder in a direction which forces liquid filling the tank to flow downward through the flow control cylinder and a second smaller propeller positioned below the larger propeller having a reverse pitch to oppose the flow of liquid being driven downward by the larger propeller.

  3. Dry skin, moisturization and corneodesmolysis.

    PubMed

    Harding, C R; Watkinson, A; Rawlings, A V; Scott, I R

    2000-02-01

    The process leading to the loss of corneocytes form the skin surface is termed desquamation. In healthy skin it is an orderly and essentially invisible process whereby individual or small groups of corneocytes detach from neighbouring cells to be lost to the environment and replaced by younger cells from the deeper layers. Desquamation is carefully controlled to ensure that corneum cohesion and integrity, and hence tissue thickness, is maintained. The most important components of the corneocytes contributing towards intercellular cohesion are the corneodesmosomes and lipids. Corneodesmosomes are proteinaceous complexes which effectively rivet corneocytes together. The intercellular lipids, primarily responsible for the water barrier, also provide part of the extracellular cement. In addition, the shape of the corneocyte itself plays a role in stratum corneum cohesion. Through interdigitation along their peripheral edges, adjacent corneocytes become physically locked together, a process which reinforces the integrity of the tissue. For effective desquamation to occur corneodesmosomes must be degraded: a process catalysed by serine proteases present within the intercellular space and facilitated by subtle changes in lipid composition and phase behaviour. Ultimately, it is the availability of free water which controls corneodesmolysis. In healthy skin this proteolytic process leaves relatively few corneodesmosomes intact in the most superficial layers. By contrast, in chronic and acute dry skin conditions, corneodesmosomal degradation and hence the final stages of desquamation are perturbed, leading to the characteristic formation of visible, powdery flakes on the skin surface. The inability to degrade these structures ultimately reflects a decreased hydrolytic activity of the desquamatory enzymes, either through reduced synthesis of the enzymes, inherent loss of activity, leaching from the surface layers of the corneum or changes in the surrounding lipid

  4. Efficiency of hand drying for removing bacteria from washed hands: comparison of paper towel drying with warm air drying.

    PubMed

    Yamamoto, Yukiko; Ugai, Kazuhiro; Takahashi, Yasuko

    2005-03-01

    To evaluate warm air and paper towel drying for removing bacteria from washed hands. After hands were washed with non-antibacterial soap, they were dried using warm air with and without ultraviolet light, while being rubbed or held stationary, or paper towels. Each method was performed as a randomized trial using 30 hands. Log colony-forming units (CFU) on palms and fingers increased significantly when hands were dried with warm air while being rubbed for 15 seconds (P < .001), and many bacteria remained at 30 seconds without ultraviolet light (P < .001) Holding hands stationary while drying significantly decreased log CFU on palms, fingers, and fingertips (P < .01 or < .001). Few CFU were detected on palms and fingers dried with ultraviolet light. Although log CFU of palms and fingers did not decrease after drying with three sheets of paper towel, those of fingertips decreased significantly (P < .001). For palms and fingers, log reductions were greater with warm air drying while holding hands stationary, paper towels, and warm air drying while rubbing hands. For fingertips, the log reduction was often greater with paper towels than with warm air. Holding hands stationary and not rubbing them was desirable for removing bacteria. Ultraviolet light reinforced the removal of bacteria during warm air drying. Paper towels were useful for removing bacteria from fingertips but not palms and fingers.

  5. Setting up the drying regimes based on the theory of moisture migration during drying

    NASA Astrophysics Data System (ADS)

    Vasić, M.; Radojević, Z.

    2016-08-01

    Drying is energy intensive process which has important effect on the quality of the clay tiles that are dried commercially. Chamber and tunnel dryers are constantly improving. Better technical equipment and operational strategies have lead to higher quality of the dried clay products. The moisture migration during isothermal drying process can be visually traced on the curve that represents the relationship between variable effective moisture diffusivity (MR) with time (t). Proposed non isothermal drying regimes were consisted from several isothermal segments. For the first time, the choice of isothermal segments specification and its duration was not specified by experience or by trial-and-error method. It was detected from the isothermal curves Deff - MR in accordance with the theory of moisture migration during drying. Proposed drying regimes were tested. Clay roofing tiles were dried without cracks. Dried clay roofing tiles has satisfied all requirements defined in EN 1304 norm related to the shape regularity and mechanical properties.

  6. A statistical approach to optimize the spray drying of starch particles: application to dry powder coating.

    PubMed

    Bilancetti, Luca; Poncelet, Denis; Loisel, Catherine; Mazzitelli, Stefania; Nastruzzi, Claudio

    2010-09-01

    This article describes the preparation of starch particles, by spray drying, for possible application to a dry powder coating process. Dry powder coating consists of spraying a fine powder and a plasticizer on particles. The efficiency of the coating is linked to the powder morphological and dimensional characteristics. Different experimental parameters of the spray-drying process were analyzed, including type of solvent, starch concentration, rate of polymer feeding, pressure of the atomizing air, drying air flow, and temperature of drying air. An optimization and screening of the experimental parameters by a design of the experiment (DOE) approach have been done. Finally, the produced spray-dried starch particles were conveniently tested in a dry coating process, in comparison to the commercial initial starch. The obtained results, in terms of coating efficiency, demonstrated that the spray-dried particles led to a sharp increase of coating efficiency value.

  7. Seeing the Carbon Cycle

    ERIC Educational Resources Information Center

    Drouin, Pamela; Welty, David J.; Repeta, Daniel; Engle-Belknap, Cheryl A.; Cramer, Catherine; Frashure, Kim; Chen, Robert

    2006-01-01

    In this article, the authors present a classroom experiment that was developed to introduce middle school learners to the carbon cycle. The experiment deals with transfer of CO[subscript 2] between liquid reservoirs and the effect CO[subscript 2] has on algae growth. It allows students to observe the influence of the carbon cycle on algae growth,…

  8. Teaching the Krebs Cycle.

    ERIC Educational Resources Information Center

    Akeroyd, F. Michael

    1983-01-01

    Outlines a simple but rigorous treatment of the Krebs Cycle suitable for A-level Biology students. The importance of the addition of water molecules in various stages of the cycle is stressed as well as the removal of hydrogen atoms by the oxidizing enzymes. (JN)

  9. Rock Cycle Roulette.

    ERIC Educational Resources Information Center

    Schmidt, Stan M.; Palmer, Courtney

    2000-01-01

    Introduces an activity on the rock cycle. Sets 11 stages representing the transitions of an earth material in the rock cycle. Builds six-sided die for each station, and students move to the stations depending on the rolling side of the die. Evaluates students by discussing several questions in the classroom. Provides instructional information for…

  10. The carbon cycle revisited

    NASA Technical Reports Server (NTRS)

    Bolin, Bert; Fung, Inez

    1992-01-01

    Discussions during the Global Change Institute indicated a need to present, in some detail and as accurately as possible, our present knowledge about the carbon cycle, the uncertainties in this knowledge, and the reasons for these uncertainties. We discuss basic issues of internal consistency within the carbon cycle, and end by summarizing the key unknowns.

  11. The Oxygen Cycle.

    ERIC Educational Resources Information Center

    Swant, Gary D.

    Produced for primary grades, this booklet provides study of the oxygen-carbon dioxide cycle in nature. Line drawings, a minimum amount of narrative, and a glossary of terms make up its content. The booklet is designed to be used as reading material, a coloring book, or for dramatic arts with students acting out parts of the cycle. This work was…

  12. Rock Cycle Roulette.

    ERIC Educational Resources Information Center

    Schmidt, Stan M.; Palmer, Courtney

    2000-01-01

    Introduces an activity on the rock cycle. Sets 11 stages representing the transitions of an earth material in the rock cycle. Builds six-sided die for each station, and students move to the stations depending on the rolling side of the die. Evaluates students by discussing several questions in the classroom. Provides instructional information for…

  13. Your Menstrual Cycle

    MedlinePlus

    ... your best Fighting germs Your sexuality What are STDs and STIs? Seeing the doctor Quizzes Links to more information on girls' ... What happens during your menstrual cycle The menstrual cycle includes not just your period, but the rise and fall of hormones and other body changes ...

  14. Measuring Cycling Effort.

    ERIC Educational Resources Information Center

    Jahnke, Thomas; Hamson, Mike

    1999-01-01

    Investigates the basic mechanics of cycling with a simple reckoning of how much effort is needed from the cyclist. The work done by the cyclist is quantified when the ride is on the flat and also when pedaling uphill. Proves that by making use of the available gears on a mountain bike, cycling uphill can be accomplished without pain. (Author/ASK)

  15. Teaching the Krebs Cycle.

    ERIC Educational Resources Information Center

    Akeroyd, F. Michael

    1983-01-01

    Outlines a simple but rigorous treatment of the Krebs Cycle suitable for A-level Biology students. The importance of the addition of water molecules in various stages of the cycle is stressed as well as the removal of hydrogen atoms by the oxidizing enzymes. (JN)

  16. Seeing the Carbon Cycle

    ERIC Educational Resources Information Center

    Drouin, Pamela; Welty, David J.; Repeta, Daniel; Engle-Belknap, Cheryl A.; Cramer, Catherine; Frashure, Kim; Chen, Robert

    2006-01-01

    In this article, the authors present a classroom experiment that was developed to introduce middle school learners to the carbon cycle. The experiment deals with transfer of CO[subscript 2] between liquid reservoirs and the effect CO[subscript 2] has on algae growth. It allows students to observe the influence of the carbon cycle on algae growth,…

  17. Power Plant Cycling Costs

    SciTech Connect

    Kumar, N.; Besuner, P.; Lefton, S.; Agan, D.; Hilleman, D.

    2012-07-01

    This report provides a detailed review of the most up to date data available on power plant cycling costs. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities.

  18. Drying apparatus for photographic sheet material

    NASA Technical Reports Server (NTRS)

    Epstein, P.; Donovan, G.; Lawhite, E. (Inventor)

    1973-01-01

    An elongated drying chamber is provided with transport means for carrying photographic sheet material edgewise with the sheets in end-to-end relationship past a plurality of tubes that issue drying air streams. The tubes are slotted a distance equal to substantially the full width of the sheet material for complete, gentle drying by sheets of air. A common plenum supplies the tubes with heated air; the air is directed from the tube slots at a pronounced angle to the sheet surface to provide for arraying the tubes close to the surface for maximum drying effect while minimizing the danger of mechanical interference between the edges of the sheets and the slots in the tubes. The driver for the transport is housed in an enclosure between the plenum and the drying chamber; an air return duct is provided along another side to complete insulation of the drying chamber from ambient conditions.

  19. Dry needling - peripheral and central considerations.

    PubMed

    Dommerholt, Jan

    2011-11-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture.

  20. Dry needling — peripheral and central considerations

    PubMed Central

    Dommerholt, Jan

    2011-01-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture. PMID:23115475

  1. Transcutaneous delivery and thermostability of a dry trivalent inactivated influenza vaccine patch

    PubMed Central

    Frolov, Vladimir G.; Seid, Robert C.; Odutayo, Olabisi; Al‐Khalili, Mohammad; Yu, Jianmei; Frolova, Olga Y.; Vu, Hong; Butler, Barbara A.; Look, Jee Loon; Ellingsworth, Larry R.; Glenn, Gregory M.

    2008-01-01

    A patch containing a trivalent inactivated influenza vaccine (TIV) was prepared in a dried, stabilized formulation for transcutaneous delivery. When used in a guinea pig immunogenicity model, the dry patch was as effective as a wet TIV patch in inducing serum anti‐influenza IgG antibodies. When the dry TIV patch was administered with LT as an adjuvant, a robust immune response was obtained that was comparable with or better than an injected TIV vaccine. When stored sealed in a nitrogen‐purged foil, the dry TIV patch was stable for 12 months, as measured by HA content, under both refrigerated and room temperature conditions. Moreover, the immunological potency of the vaccine product was not affected by long‐term storage. The dry TIV patch was also thermostable against three cycles of alternating low‐to‐high temperatures of −20/25 and −20/40°C, and under short‐term temperature stress conditions. These studies indicate that the dry TIV patch product can tolerate unexpected environmental stresses that may be encountered during shipping and distribution. Because of its effectiveness in vaccine delivery and its superior thermostable characteristics, the dry TIV patch represents a major advance for needle‐free influenza vaccination. PMID:19453472

  2. Bacterial regrowth potential in alkaline sludges from open-sun and covered sludge drying beds.

    PubMed

    Alkan, U; Topaç, F O; Birden, B; Baskaya, H S

    2007-10-01

    The aim of this study was to compare the regrowth potentials of wastewater sludges dried in two pilot-scale drying processes namely, Open-Sun Sludge Drying Bed (OSDB) and Covered Sludge Drying Bed (CSDB). Quicklime and/or coal fly ash were added to raw sludge samples prior to drying processes in order to enhance bacterial inactivation. Following three drying cycles (March-April, June-July and August-October), sludge samples were taken from the beds for the regrowth experiments. Addition of alkaline materials prevented the regrowth of faecal coliforms in all rewetted samples except for the samples obtained after the rainfall events in OSDB. Rewetting of these samples in the regrowth experiments increased faecal coliform numbers by 3.5-7 log units. In contradiction, the observed bacterial numbers in rewetted alkaline samples from CSDB were below the EPA Class B criterion (2 million MPN g(-1) dry sludge). The combination of additional heat from solar collectors, protection from the rain and the unfavourable living conditions owing to alkaline materials appeared to inactivate bacteria more effectively in CSDB and hence eliminated regrowth potential more efficiently.

  3. Predicting the Sunspot Cycle

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    The 11-year sunspot cycle was discovered by an amateur astronomer in 1844. Visual and photographic observations of sunspots have been made by both amateurs and professionals over the last 400 years. These observations provide key statistical information about the sunspot cycle that do allow for predictions of future activity. However, sunspots and the sunspot cycle are magnetic in nature. For the last 100 years these magnetic measurements have been acquired and used exclusively by professional astronomers to gain new information about the nature of the solar activity cycle. Recently, magnetic dynamo models have evolved to the stage where they can assimilate past data and provide predictions. With the advent of the Internet and open data policies, amateurs now have equal access to the same data used by professionals and equal opportunities to contribute (but, alas, without pay). This talk will describe some of the more useful prediction techniques and reveal what they say about the intensity of the upcoming sunspot cycle.

  4. Predicting the Sunspot Cycle

    NASA Technical Reports Server (NTRS)

    Hathaway, David H.

    2009-01-01

    The 11-year sunspot cycle was discovered by an amateur astronomer in 1844. Visual and photographic observations of sunspots have been made by both amateurs and professionals over the last 400 years. These observations provide key statistical information about the sunspot cycle that do allow for predictions of future activity. However, sunspots and the sunspot cycle are magnetic in nature. For the last 100 years these magnetic measurements have been acquired and used exclusively by professional astronomers to gain new information about the nature of the solar activity cycle. Recently, magnetic dynamo models have evolved to the stage where they can assimilate past data and provide predictions. With the advent of the Internet and open data policies, amateurs now have equal access to the same data used by professionals and equal opportunities to contribute (but, alas, without pay). This talk will describe some of the more useful prediction techniques and reveal what they say about the intensity of the upcoming sunspot cycle.

  5. A dynamic fuel cycle analysis for a heterogeneous thorium-DUPIC recycle in CANDU reactors

    SciTech Connect

    Jeong, C. J.; Park, C. J.; Choi, H.

    2006-07-01

    A heterogeneous thorium fuel recycle scenario in a Canada deuterium uranium (CANDU) reactor has been analyzed by the dynamic analysis method. The thorium recycling is performed through a dry process which has a strong proliferation resistance. In the fuel cycle model, the existing nuclear power plant construction plan was considered up to 2016, while the nuclear demand growth rate from the year 2016 was assumed to be 0%. In this analysis, the spent fuel inventory as well as the amount of plutonium, minor actinides, and fission products of a multiple thorium recycling fuel cycle were estimated and compared to those of the once-through fuel cycle. The analysis results have shown that the heterogeneous thorium fuel cycle can be constructed through the dry process technology. It is also shown that the heterogeneous thorium fuel cycle can reduce the spent fuel inventory and save on the natural uranium resources when compared with the once-through cycle. (authors)

  6. Thin layer drying of tomato slices.

    PubMed

    Das Purkayastha, Manashi; Nath, Amit; Deka, Bidyut Chandra; Mahanta, Charu Lata

    2013-08-01

    The hot air convective drying characteristics of blanched tomato (Lycopersicon esculantum L.) slices have been investigated. Drying experiments were carried out at four different temperatures (50, 60, 65 and 70 °C). The effect of drying temperatures on the drying behavior of the tomato slices was evaluated. All drying experiments had only falling rate period. The average effective diffusivity values varied from 0.5453 × 10(-9) to 2.3871 × 10(-9) m(2)/s over the temperature range studied and the activation energy was estimated to be 61.004 kJ/mol. In order to select a suitable form of the drying curve, six different thin layer drying models (Henderson-Pabis, Page, Diamante et al., Wang and Singh, Logarithmic and Newton models) were fitted to the experimental data. The goodness of fit tests indicated that the Logarithmic model gave the best fit to experimental results, which was closely followed by the Henderson-Pabis model. The influence of varied drying temperatures on quality attributes of the tomato slices viz. Hunter color parameters, ascorbic acid, lycopene, titratable acidity, total sugars, reducing sugars and sugar/acid ratio of dried slices was also studied. Slices dried at 50 and 60 °C had high amount of total sugars, lycopene, sugar/acid ratio, Hunter L- and a-values. Drying of slices at 50 °C revealed optimum retention of ascorbic acid, sugar/acid ratio and red hue, whereas, drying at higher temperature (65 and 70 °C) resulted in a considerable decrease in nutrients and colour quality of the slices.

  7. [An experience of dried cornea transplantation].

    PubMed

    Gundorova, R A; Chentsova, E V; Makarov, P V; Kugusheva, A É; Rakova, A V

    2011-01-01

    Sometimes an urgent lamellar keratoplasty remains the only treatment option for corneal defect closure. When fresh donor tissue is absent as it is regular in recent years dried cornea transplantation becomes reasonable. In recent years in ocular trauma department 320 transplantations of dried on silicagel cornea were performed. Analysis of results allows to conclude that use of dried cornea is a promising surgical procedure to preserve the globe and in some cases to prepare the eye with severe trauma for subsequent optic surgery.

  8. Wet/dry cooling tower and method

    DOEpatents

    Glicksman, Leon R.; Rohsenow, Warren R.

    1981-01-01

    A wet/dry cooling tower wherein a liquid to-be-cooled is flowed along channels of a corrugated open surface or the like, which surface is swept by cooling air. The amount of the surface covered by the liquid is kept small compared to the dry part thereof so that said dry part acts as a fin for the wet part for heat dissipation.

  9. The Chlamydomonas cell cycle.

    PubMed

    Cross, Frederick R; Umen, James G

    2015-05-01

    The position of Chlamydomonas within the eukaryotic phylogeny makes it a unique model in at least two important ways: as a representative of the critically important, early-diverging lineage leading to plants; and as a microbe retaining important features of the last eukaryotic common ancestor (LECA) that has been lost in the highly studied yeast lineages. Its cell biology has been studied for many decades and it has well-developed experimental genetic tools, both classical (Mendelian) and molecular. Unlike land plants, it is a haploid with very few gene duplicates, making it ideal for loss-of-function genetic studies. The Chlamydomonas cell cycle has a striking temporal and functional separation between cell growth and rapid cell division, probably connected to the interplay between diurnal cycles that drive photosynthetic cell growth and the cell division cycle; it also exhibits a highly choreographed interaction between the cell cycle and its centriole-basal body-flagellar cycle. Here, we review the current status of studies of the Chlamydomonas cell cycle. We begin with an overview of cell-cycle control in the well-studied yeast and animal systems, which has yielded a canonical, well-supported model. We discuss briefly what is known about similarities and differences in plant cell-cycle control, compared with this model. We next review the cytology and cell biology of the multiple-fission cell cycle of Chlamydomonas. Lastly, we review recent genetic approaches and insights into Chlamydomonas cell-cycle regulation that have been enabled by a new generation of genomics-based tools. © 2015 The Authors The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.

  10. Dry Eye: an Inflammatory Ocular Disease

    PubMed Central

    Hessen, Michelle; Akpek, Esen Karamursel

    2014-01-01

    Keratoconjunctivitis sicca, or dry eye, is a common ocular disease prompting millions of individuals to seek ophthalmological care. Regardless of the underlying etiology, dry eye has been shown to be associated with abnormalities in the pre-corneal tear film and subsequent inflammatory changes in the entire ocular surface including the adnexa, conjunctiva and cornea. Since the recognition of the role of inflammation in dry eye, a number of novel treatments have been investigated designed to inhibit various inflammatory pathways. Current medications that are used, including cyclosporine A, corticosteroids, tacrolimus, tetracycline derivatives and autologous serum, have been effective for management of dry eye and lead to measurable clinical improvement. PMID:25279127

  11. FINAL REPORT: Transformational electrode drying process

    SciTech Connect

    Claus Daniel, C.; Wixom, M.

    2013-12-19

    This report includes major findings and outlook from the transformational electrode drying project performance period from January 6, 2012 to August 1, 2012. Electrode drying before cell assembly is an operational bottleneck in battery manufacturing due to long drying times and batch processing. Water taken up during shipment and other manufacturing steps needs to be removed before final battery assembly. Conventional vacuum ovens are limited in drying speed due to a temperature threshold needed to avoid damaging polymer components in the composite electrode. Roll to roll operation and alternative treatments can increase the water desorption and removal rate without overheating and damaging other components in the composite electrode, thus considerably reducing drying time and energy use. The objective of this project was the development of an electrode drying procedure, and the demonstration of processes with no decrease in battery performance. The benchmark for all drying data was an 80°C vacuum furnace treatment with a residence time of 18 – 22 hours. This report demonstrates an alternative roll to roll drying process with a 500-fold improvement in drying time down to 2 minutes and consumption of only 30% of the energy compared to vacuum furnace treatment.

  12. Optimal energy management in grain drying.

    PubMed

    Gunasekaran, S

    1986-01-01

    Grain drying is very specific to the geographic location, kind of drying system, and the type of grain. Under a given set of conditions, the optimal system can be selected based on careful evaluation. However, a good choice of drying systems, procedures, and management practices can be made from the information already available. The review of several grain-drying procedures has provided some insight in making a quick evaluation of the process and arriving at the most suitable system for a particular application. Despite extensive research efforts, the present knowledge of grain drying is yet insufficient to optimally design each drying process with respect to capacity, quality, and energy requirement. There is a need for incorporating grain and air parameters more accurately. It is also important to develop comprehensive drying simulation models to encompass agronomic practices, such as planting and harvesting. Recent efforts indicate a strong influence of planting and harvesting strategies on optimal drying and storage system selection. Results of the varietal trials at Ohio State University indicate that it is now possible to select midseason varieties, which dry down rapidly, without sacrificing yield. Also, low moisture at harvest is important to the energy management process because it affects total drying time and energy required. It is also important from a quality standpoint because kernel damage increases rapidly at harvesting moisture levels above 25%. The trend in grain-dryer design has shifted from focusing on drying capacity and operation reliability to energy consumption. The development in design of energy efficient continuous-flow dryers has been significant. Multistage concurrentflow dryers are excellent examples. Various aspects of dryer staging for efficient operation and control are yet to be determined. Recirculation of the exhaust air is a proven method of improving energy efficiency. Likewise, in batch-in-bin systems, stirring and

  13. Cold vacuum drying facility design requirements

    SciTech Connect

    IRWIN, J.J.

    1999-07-01

    This document provides the detailed design requirements for the Spent Nuclear Fuel Project Cold Vacuum Drying Facility. Process, safety, and quality assurance requirements and interfaces are specified.

  14. Liquid Crystal Research Shows Deformation By Drying

    NASA Technical Reports Server (NTRS)

    2003-01-01

    These images, from David Weitz's liquid crystal research, show ordered uniform sized droplets (upper left) before they are dried from their solution. After the droplets are dried (upper right), they are viewed with crossed polarizers that show the deformation caused by drying, a process that orients the bipolar structure of the liquid crystal within the droplets. When an electric field is applied to the dried droplets (lower left), and then increased (lower right), the liquid crystal within the droplets switches its alignment, thereby reducing the amount of light that can be scattered by the droplets when a beam is shone through them.

  15. Recent developments in drying of food products

    NASA Astrophysics Data System (ADS)

    Valarmathi, T. N.; Sekar, S.; Purushothaman, M.; Sekar, S. D.; Rama Sharath Reddy, Maddela; Reddy, Kancham Reddy Naveen Kumar

    2017-05-01

    Drying is a dehydration process to preserve agricultural products for long period usage. The most common and cheapest method is open sun drying in which the products are simply laid on ground, road, mats, roof, etc. But the open sun drying has some disadvantages like dependent on good weather, contamination by dust, birds and animals consume a considerable quantity, slow drying rate and damages due to strong winds and rain. To overcome these difficulties solar dryers are developed with closed environment for drying agricultural products effectively. To obtain good quality food with reduced energy consumption, selection of appropriate drying process and proper input parameters is essential. In recent years several researchers across the world have developed new drying systems for improving the product quality, increasing the drying rate, decreasing the energy consumption, etc. Some of the new systems are fluidized bed, vibrated fluidized bed, desiccant, microwave, vacuum, freeze, infrared, intermittent, electro hydrodynamic and hybrid dryers. In this review the most recent progress in the field of drying of agricultural food products such as new methods, new products and modeling and optimization techniques has been presented. Challenges and future directions are also highlighted. The review will be useful for new researchers entering into this ever needed and ever growing field of engineering.

  16. Drying of Pigment-Cellulose Nanofibril Substrates

    PubMed Central

    Timofeev, Oleg; Torvinen, Katariina; Sievänen, Jenni; Kaljunen, Timo; Kouko, Jarmo; Ketoja, Jukka A.

    2014-01-01

    A new substrate containing cellulose nanofibrils and inorganic pigment particles has been developed for printed electronics applications. The studied composite structure contains 80% fillers and is mechanically stable and flexible. Before drying, the solids content can be as low as 20% due to the high water binding capacity of the cellulose nanofibrils. We have studied several drying methods and their effects on the substrate properties. The aim is to achieve a tight, smooth surface keeping the drying efficiency simultaneously at a high level. The methods studied include: (1) drying on a hot metal surface; (2) air impingement drying; and (3) hot pressing. Somewhat surprisingly, drying rates measured for the pigment-cellulose nanofibril substrates were quite similar to those for the reference board sheets. Very high dewatering rates were observed for the hot pressing at high moisture contents. The drying method had significant effects on the final substrate properties, especially on short-range surface smoothness. The best smoothness was obtained with a combination of impingement and contact drying. The mechanical properties of the sheets were also affected by the drying method and associated temperature. PMID:28788220

  17. New Processes for Freeze-Drying in Dual-Chamber Systems.

    PubMed

    Werk, T; Ludwig, I S; Luemkemann, J; Huwyler, J; Mahler, H-C; Haeuser, C R; Hafner, M

    2016-01-01

    Dual-chamber systems can offer self-administration and home care use for lyophilized biologics. Only a few products have been launched in dual-chamber systems so far-presumably due to dual-chamber systems' complex and costly drug product manufacturing process. Within this paper, two improved processes (both based on tray filling technology) for freeze-drying pharmaceuticals in dual-chamber systems are described. Challenges with regards to heat transfer were tackled by (1) performing the freeze-drying step in a needle-down orientation in combination with an aluminum block, or (2) freeze-drying the drug product "externally" in a metal cartridge with subsequent filling of the lyophilized cake into the dual-chamber system. Metal-mediated heat transfer was shown to be efficient in both cases and batch (unit-to-unit) homogeneity with regards to sublimation rate was increased. It was difficult to influence ice crystal size using different methods when in use with an aluminum block due to its heat capacity. Using such a metal carrier implies a large heat capacity leading to relatively small ice crystals. Compared to the established process, drying times were reduced by half using the new processes. The drying time was, however, longer for syringes compared to vials due to the syringe design (long and slim). The differences in drying times were less pronounced for aggressive drying cycles. The proposed processes may help to considerably decrease investment costs into dual-chamber system fill-finish equipment. Dual-chamber syringes offer self-administration and home care use for freeze-dried pharmaceuticals. Only a few products have been launched in dual-chamber syringes so far-presumably due to their complex and costly drug product manufacturing process. In this paper two improved processes for freeze-drying pharmaceuticals in dual-chamber syringes are described. The major challenge of freeze-drying is to transfer heat through a vacuum. The proposed processes cope with this

  18. Effect of different drying technologies on drying characteristics and quality of red pepper (Capsicum frutescens L.): a comparative study.

    PubMed

    Cao, Zhen-Zhen; Zhou, Lin-Yan; Bi, Jin-Feng; Yi, Jian-Yong; Chen, Qin-Qin; Wu, Xin-Ye; Zheng, Jin-Kai; Li, Shu-Rong

    2016-08-01

    Hot air drying and sun drying are traditional drying technologies widely used in the drying of agricultural products for a long time, but usually recognized as time-consuming or producing lower-quality products. Infrared drying is a rather effective drying technology that has advantages over traditional drying technologies. Thus, in order to investigate the application of infrared drying in the dehydration of red pepper, the drying characteristics and quality of infrared-dried red pepper were compared with those of sun-dried and hot air-dried red pepper. The infrared drying technology significantly enhanced the drying rate when compared with hot air drying and sun drying. Temperature was the most important factor affecting the moisture transfer during the process of infrared drying as well as hot air drying. Effective moisture diffusivity (Deff ) values of infrared drying ranged from 1.58 × 10(-9) to 3.78 × 10(-9) m(2) s(-1) . The Ea values of infrared drying and hot air drying were 42.67 and 44.48 kJ mol(-1) respectively. Infrared drying and hot air drying produced color loss to a similar extent. Relatively higher crispness values were observed for infrared-dried samples. Sun drying produced dried red pepper with the best color when compared with hot air drying and infrared drying. Meanwhile, infrared drying markedly improved the drying rate at the same drying temperature level of hot air drying, and the products obtained had relatively better quality with higher crispness values. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  19. Host selection and gonotrophic cycle length of Anopheles punctimacula in southern Mexico.

    PubMed

    Ulloa, Armando; Gonzalez-Cerón, Lilia; Rodríguez, Mario H

    2006-12-01

    The host preference, survival rates, and length of the gonotrophic cycle of Anopheles punctimacula was investigated in southern México. Mosquitoes were collected in 15-day separate experiments during the rainy and dry seasons. Daily changes in the parous-nulliparous ratio were recorded and the gonotrophic cycle length was estimated by a time series analysis. Anopheles punctimacula was most abundant during the dry season and preferred animals to humans. The daily survival rate in mosquitoes collected in animal traps was 0.96 (parity rate = 0.86; gonotrophic cycle = 4 days). The length of gonotrophic cycle of 4 days was estimated on the base of a high correlation coefficient value appearing every 4 days. The minimum time estimated for developing mature eggs after blood feeding was 72 h. The proportion of mosquitoes living enough to transmit Plasmodium vivax malaria during the dry season was 0.35.

  20. Effect of season on the oestrous cycle of cows (Bos indicus) indigenous to northern Nigeria.

    PubMed

    Zakari, A Y; Molokwu, E C; Osori, D I

    1981-09-12

    A seasonal effect was demonstrated on the occurrence of oestrus and on the length of oestrous cycles in Bunaji and Bokoloji cows. There was a gradual lengthening of oestrous cycle which resulted in fewer cycles occurring in the dry and pre-rainy seasons. Oestrous cycle length was the same for Bunaji (22.89 +/-0.70 days) and Bokoloji (23.76 +/- 0.65 days) cows (P less than 0.05). Season had an equally depressing effect on the duration and intensity of oestrus in both breeds of cows. During the dry and pre-rainy seasons the behavioural signs of oestrus were poorly manifested and lasted for only a short period. During the rainy and pre-dry seasons, the duration of oestrus and behavioural signs were much more pronounced.

  1. Modeling seasonal surface temperature variations in secondary tropical dry forests

    NASA Astrophysics Data System (ADS)

    Cao, Sen; Sanchez-Azofeifa, Arturo

    2017-10-01

    Secondary tropical dry forests (TDFs) provide important ecosystem services such as carbon sequestration, biodiversity conservation, and nutrient cycle regulation. However, their biogeophysical processes at the canopy-atmosphere interface remain unknown, limiting our understanding of how this endangered ecosystem influences, and responds to the ongoing global warming. To facilitate future development of conservation policies, this study characterized the seasonal land surface temperature (LST) behavior of three successional stages (early, intermediate, and late) of a TDF, at the Santa Rosa National Park (SRNP), Costa Rica. A total of 38 Landsat-8 Thermal Infrared Sensor (TIRS) data and the Surface Reflectance (SR) product were utilized to model LST time series from July 2013 to July 2016 using a radiative transfer equation (RTE) algorithm. We further related the LST time series to seven vegetation indices which reflect different properties of TDFs, and soil moisture data obtained from a Wireless Sensor Network (WSN). Results showed that the LST in the dry season was 15-20 K higher than in the wet season at SRNP. We found that the early successional stages were about 6-8 K warmer than the intermediate successional stages and were 9-10 K warmer than the late successional stages in the middle of the dry season; meanwhile, a minimum LST difference (0-1 K) was observed at the end of the wet season. Leaf phenology and canopy architecture explained most LST variations in both dry and wet seasons. However, our analysis revealed that it is precipitation that ultimately determines the LST variations through both biogeochemical (leaf phenology) and biogeophysical processes (evapotranspiration) of the plants. Results of this study could help physiological modeling studies in secondary TDFs.

  2. Transient Load Following and Control Analysis of Advanced S-CO2 Power Conversion with Dry Air Cooling

    SciTech Connect

    Moisseytsev, Anton; Sienicki, James J.

    2016-01-01

    Supercritical carbon dioxide (S-CO2) Brayton cycles are under development as advanced energy converters for advanced nuclear reactors, especially the Sodium-Cooled Fast Reactor (SFR). The use of dry air cooling for direct heat rejection to the atmosphere ultimate heat sink is increasingly becoming a requirement in many regions due to restrictions on water use. The transient load following and control behavior of an SFR with an S-CO2 cycle power converter utilizing dry air cooling have been investigated. With extension and adjustment of the previously existing control strategy for direct water cooling, S-CO2 cycle power converters can also be used for load following operation in regions where dry air cooling is a requirement

  3. Two Quantum Polytropic Cycles

    NASA Astrophysics Data System (ADS)

    Arias-Hernández, L. A.; Morales-Serrano, A. F.

    2002-11-01

    In this work we follow the Bender et al paper [1] to study the quantum analogues of the Stirling and Ericsson polytropic cycles. In the context of the classical thermodynamics, the Stirling and Ericsson cycles correspond to reversible heat engines with two isothermal processes joined by two polytropic branches which occur in a device called regenerator. If this device is an ideal one, the efficiency of these cycles is the Carnot efficiency. Here, we introduce the quantum analogues of the Stirling and Ericsson cycles, the first one based on a double square potential well with a finite potential barrier, since in this system the tunnel effect could be the analogue to the regeneration classical process, therefore the isochoric quantum branches would really correspond to an internal energy storage, and the last one with an unknown system where the isobaric quantum processes don't induce changes in its quantum state. With these systems the quantum engines have cycles consisting of polytropic and isothermal quantum processes analogues to the corresponding classical processes. We show that in both cases the quantum cycles have an efficiency given by ηCQM = 1 - EC/EH, which is the same expression for the quantum analogue of the Carnot cycle studied by Bender.

  4. Applied physiology of cycling.

    PubMed

    Faria, I E

    1984-01-01

    Historically, the bicycle has evolved through the stages of a machine for efficient human transportation, a toy for children, a finely-tuned racing machine, and a tool for physical fitness development, maintenance and testing. Recently, major strides have been made in the aerodynamic design of the bicycle. These innovations have resulted in new land speed records for human powered machines. Performance in cycling is affected by a variety of factors, including aerobic and anaerobic capacity, muscular strength and endurance, and body composition. Bicycle races range from a 200m sprint to approximately 5000km. This vast range of competitive racing requires special attention to the principle of specificity of training. The physiological demands of cycling have been examined through the use of bicycle ergometers, rollers, cycling trainers, treadmill cycling, high speed photography, computer graphics, strain gauges, electromyography, wind tunnels, muscle biopsy, and body composition analysis. These techniques have been useful in providing definitive data for the development of a work/performance profile of the cyclist. Research evidence strongly suggests that when measuring the cyclist's aerobic or anaerobic capacity, a cycling protocol employing a high pedalling rpm should be used. The research bicycle should be modified to resemble a racing bicycle and the cyclist should wear cycling shoes. Prolonged cycling requires special nutritional considerations. Ingestion of carbohydrates, in solid form and carefully timed, influences performance. Caffeine appears to enhance lipid metabolism. Injuries, particularly knee problems which are prevalent among cyclists, may be avoided through the use of proper gearing and orthotics. Air pollution has been shown to impair physical performance. When pollution levels are high, training should be altered or curtailed. Effective training programmes simulate competitive conditions. Short and long interval training, blended with long

  5. Experimental Performance of a Thermoelectric Heat-Pump Drying System for Drying Herbs

    NASA Astrophysics Data System (ADS)

    Wongsim, K.; Jamradloedluk, J.; Lertsatitthanakorn, C.; Siriamornpun, S.; Rungsiyopas, M.; Soponronnarit, S.

    2015-06-01

    In this study we investigated thermoelectric (TE) heat-pump drying of laurel clock vine leaves, and the effect of drying-air temperature on the characteristics of the leaves. The TE drying system comprised four TE modules each with its own rectangular fin heat sink. The hot side of each TE module was fixed to its own heat sink; the cold sides were fixed to heat-pipe heat sinks and a drying chamber. The drying time depended on drying-air temperature. The heating capacity and coefficient of performance (COP) increased as the current supplied to the TE modules was increased. Calculated COP for the entire TE heat-pump drying system were 1.28 and 0.81 for drying-air temperatures of 50 and 40°C, respectively.

  6. Modification of the solid-state nature of sulfathiazole and sulfathiazole sodium by spray drying.

    PubMed

    Bianco, Stefano; Caron, Vincent; Tajber, Lidia; Corrigan, Owen I; Nolan, Lorraine; Hu, Yun; Healy, Anne Marie

    2012-06-01

    Solid-state characterisation of a drug following pharmaceutical processing and upon storage is fundamental to successful dosage form development. The aim of the study was to investigate the effects of using different solvents, feed concentrations and spray drier configuration on the solid-state nature of the highly polymorphic model drug, sulfathiazole (ST) and its sodium salt (STNa). The drugs were spray-dried from ethanol, acetone and mixtures of these organic solvents with water. Additionally, STNa was spray-dried from pure water. The physicochemical properties including the physical stability of the spray-dried powders were compared to the unprocessed materials. Spray drying of ST from either acetonic or ethanolic solutions with the spray drier operating in a closed cycle mode yielded crystalline powders. In contrast, the powders obtained from ethanolic solutions with the spray drier operating in an open cycle mode were amorphous. Amorphous ST crystallised to pure form I at ≤35 % relative humidity (RH) or to polymorphic mixtures at higher RH values. The usual crystal habit of form I is needle-like, but spherical particles of this polymorph were generated by spray drying. STNa solutions resulted in an amorphous material upon processing, regardless of the solvent and the spray drier configuration employed. Moisture induced crystallisation of amorphous STNa to a sesquihydrate, whilst crystallisation upon heating gave rise to a new anhydrous polymorph. This study indicated that control of processing and storage parameters can be exploited to produce drugs with a specific/desired solid-state nature.

  7. Nutrient addition effects on tropical dry forests: a mini-review from microbial to ecosystem scales

    NASA Astrophysics Data System (ADS)

    Powers, Jennifer; Becklund, Kristen; Gei, Maria; Iyengar, Siddarth; Meyer, Rebecca; O'Connell, Christine; Schilling, Erik; Smith, Christina; Waring, Bonnie; Werden, Leland

    2015-06-01

    Humans have more than doubled inputs of reactive nitrogen globally and greatly accelerated the biogeochemical cycles of phosphorus and metals. However, the impacts of increased element mobility on tropical ecosystems remain poorly quantified, particularly for the vast tropical dry forest biome. Tropical dry forests are characterized by marked seasonality, relatively little precipitation, and high heterogeneity in plant functional diversity and soil chemistry. For these reasons, increased nutrient deposition may affect tropical dry forests differently than wet tropical or temperate forests. Here we review studies that investigated how nutrient availability affects ecosystem and community processes from the microsite to ecosystem scales in tropical dry forests. The effects of N and P addition on ecosystem carbon cycling and plant and microbial dynamics depend on forest successional stage, soil parent material and rainfall regime. Responses may depend on whether overall productivity is N- versus P-limited, although data to test this hypothesis are limited. These results highlight the many important gaps in our understanding of tropical dry forest responses to global change. Large-scale experiments are required to resolve these uncertainties.

  8. Direct spray drying and microencapsulation of probiotic Lactobacillus reuteri from slurry fermentation with whey.

    PubMed

    Jantzen, M; Göpel, A; Beermann, C

    2013-10-01

    Formulations of dietary probiotics have to be robust against process conditions and have to maintain a sufficient survival rate during gastric transit. To increase efficiency of the encapsulation process and the viability of applied bacteria, this study aimed at developing spray drying and encapsulation of Lactobacillus reuteri with whey directly from slurry fermentation. Lactobacillus reuteri was cultivated in watery 20% (w/v) whey solution with or without 0·5% (w/v) yeast extract supplementation in a submerged slurry fermentation. Growth enhancement with supplement was observed. Whey slurry containing c. 10(9)  CFU g(-1) bacteria was directly spray-dried. Cell counts in achieved products decreased by 2 log cycles after drying and 1 log cycle during 4 weeks of storage. Encapsulated bacteria were distinctively released in intestinal milieu. Survival rate of encapsulated bacteria was 32% higher compared with nonencapsulated ones exposed to artificial digestive juice. Probiotic L. reuteri proliferate in slurry fermentation with yeast-supplemented whey and enable a direct spray drying in whey. The resulting microcapsules remain stable during storage and reveal adequate survival in simulated gastric juices and a distinct release in intestinal juices. Exploiting whey as a bacterial substrate and encapsulation matrix within a coupled fermentation and spray-drying process offers an efficient option for industrial production of vital probiotics. © 2013 The Society for Applied Microbiology.

  9. Sensitivity of Amazonian TOA flux diurnal cycle composite monthly variability to choice of reanalysis

    NASA Astrophysics Data System (ADS)

    Dodson, J. Brant; Taylor, Patrick C.

    2016-05-01

    Amazonian deep convection experiences a strong diurnal cycle driven by the cycle in surface sensible heat flux, which contributes to a significant diurnal cycle in the top of the atmosphere (TOA) radiative flux. Even when accounting for seasonal variability, the TOA flux diurnal cycle varies significantly on the monthly timescale. Previous work shows evidence supporting a connection between variability in the convective and radiative cycles, likely modulated by variability in monthly atmospheric state (e.g., convective instability). The hypothesized relationships are further investigated with regression analysis of the radiative diurnal cycle and atmospheric state using additional meteorological variables representing convective instability and upper tropospheric humidity. The results are recalculated with three different reanalyses to test the reliability of the results. The radiative diurnal cycle sensitivity to upper tropospheric humidity is about equal in magnitude to that of convective instability. In addition, the results are recalculated with the data subdivided into the wet and dry seasons. Overall, clear-sky radiative effects have a dominant role in radiative diurnal cycle variability during the dry season. Because of this, even in a convectively active region, the clear-sky radiative effects must be accounted for in order to fully explain the monthly variability in diurnal cycle. Finally, while there is general agreement between the different reanalysis-based results when examining the full data time domain (without regard to time of year), there are significant disagreements when the data are divided into wet and dry seasons. The questionable reliability of reanalysis data is a major limitation.

  10. Sensitivity of Amazonian TOA flux diurnal cycle composite monthly variability to choice of reanalysis.

    PubMed

    Dodson, J Brant; Taylor, Patrick C

    2016-05-16

    Amazonian deep convection experiences a strong diurnal cycle driven by the cycle in surface sensible heat flux, which contributes to a significant diurnal cycle in the top of the atmosphere (TOA) radiative flux. Even when accounting for seasonal variability, the TOA flux diurnal cycle varies significantly on the monthly timescale. Previous work shows evidence supporting a connection between variability in the convective and radiative cycles, likely modulated by variability in monthly atmospheric state (e.g., convective instability). The hypothesized relationships are further investigated with regression analysis of the radiative diurnal cycle and atmospheric state using additional meteorological variables representing convective instability and upper tropospheric humidity. The results are recalculated with three different reanalyses to test the reliability of the results. The radiative diurnal cycle sensitivity to upper tropospheric humidity is about equal in magnitude to that of convective instability. In addition, the results are recalculated with the data subdivided into the wet and dry seasons. Overall, clear-sky radiative effects have a dominant role in radiative diurnal cycle variability during the dry season. Because of this, even in a convectively active region, the clear-sky radiative effects must be accounted for in order to fully explain the monthly variability in diurnal cycle. Finally, while there is general agreement between the different reanalysis-based results when examining the full data time domain (without regard to time of year), there are significant disagreements when the data are divided into wet and dry seasons. The questionable reliability of reanalysis data is a major limitation.

  11. GCM simulations of cold dry Snowball Earth atmospheres

    NASA Astrophysics Data System (ADS)

    Voigt, A.; Held, I.; Marotzke, J.

    2009-12-01

    We use the full-physics atmospheric general circulation model ECHAM5 to investigate cold and virtually dry Snowball Earth atmospheres. These result from specifying sea ice as the surface boundary condition everywhere, corresponding to a frozen aquaplanet, while keeping total solar irradiance at its present-day value of 1365 Wm-2 and setting atmospheric carbon dioxide to 300 ppmv. Here, we present four simulations corresponding to the four possible combinations of enabled or disabled diurnal and seasonal cycles. The aim of this study is twofold. First, we focus on the zonal-mean circulation of Snowball Earth atmospheres, which, due to missing moisture, might constitute an ideal though yet unexplored testbed for theories of atmospheric dynamics. Second, we investigate tropical surface temperatures with an emphasis on the impact of the diurnal and seasonal cycles. This will indicate whether the presence of the diurnal or seasonal cycle would facilitate or anticipate the escape from Snowball Earth conditions when total solar irradiance or atmospheric CO2 levels were increased. The dynamics of the tropical circulation in Snowball Earth atmospheres differs substantially from that in the modern atmosphere. The analysis of the mean zonal momentum budget reveals that the mean flow meridional advection of absolute vorticity is primarily balanced by vertical diffusion of zonal momentum. The contribution of eddies is found to be even smaller than the contribution of mean flow vertical advection of zonal momentum, the latter being usually neglected in theories for the Hadley circulation, at least in its upper tropospheric branch. Suppressing vertical diffusion of horizontal momentum above 850 hPa leads to a stronger Hadley circulation. This behaviour cannot be understood from axisymmetric models of the atmosphere, nor idealized atmospheric general circulation models, which both predict a weakening of the Hadley circulation when the vertical viscosity is decreased globally. We

  12. Spray drying technique. I: Hardware and process parameters.

    PubMed

    Cal, Krzysztof; Sollohub, Krzysztof

    2010-02-01

    Spray drying is a transformation of feed from a fluid state into a dried particulate form by spraying the feed into a hot drying medium. The main aim of drying by this method in pharmaceutical technology is to obtain dry particles with desired properties. This review presents the hardware and process parameters that affect the properties of the dried product. The atomization devices, drying chambers, air-droplet contact systems, the collection of dried product, auxiliary devices, the conduct of the spray drying process, and the significance of the individual parameters in the drying process, as well as the obtained product, are described and discussed.

  13. EMISSIONS OF PERCHLOROETHYLENE FROM DRY CLEANED FABRICS

    EPA Science Inventory

    A study was conducted to evaluate the emissions of perchloroethylene (tetrachloroethylene) from dry cleaned fabrics to determine: (a) how the introduction of fresh dry cleaning into a home affects the indoor concentration of perchloroethylene, and (b) the effectiveness of ‘airing...

  14. A survey of Bolivian lumber drying operations

    Treesearch

    Omar A. Espinoza; Brian H. Bond; Philip Araman

    2007-01-01

    The Bolivian secondary forest products industry has experienced substantial growth during the last 10 years. Particularly, important investment has taken place in lumber drying capacity. Unfortunately, little information is available regarding lumber drying technology and practices used, which is essential for the formulation of improvement strategies. The Bolivian...

  15. EMISSIONS OF PERCHLOROETHYLENE FROM DRY CLEANED FABRICS

    EPA Science Inventory

    A study was conducted to evaluate the emissions of perchloroethylene (tetrachloroethylene) from dry cleaned fabrics to determine: (a) how the introduction of fresh dry cleaning into a home affects the indoor concentration of perchloroethylene, and (b) the effectiveness of ‘airing...

  16. Dry phase reactor for generating medical isotopes

    DOEpatents

    Mackie, Thomas Rockwell; Heltemes, Thad Alexander

    2016-05-03

    An apparatus for generating medical isotopes provides for the irradiation of dry-phase, granular uranium compounds which are then dissolved in a solvent for separation of the medical isotope from the irradiated compound. Once the medical isotope is removed, the dissolved compound may be reconstituted in dry granular form for repeated irradiation.

  17. WET AND DRY SCRUBBERS FOR EMISSION CONTROL

    EPA Science Inventory

    Generally speaking, absorption equipment includes two major categories: Wet adsorption scrubbers (or wet scrubbers); Dry absorption scrubbers (or dry scrubbers).
    Wet scrubbers: As the name implies, wet scrubbers (also known as wet collectors) are devices which use a liquid fo...

  18. WET AND DRY SCRUBBERS FOR EMISSION CONTROL

    EPA Science Inventory

    Generally speaking, absorption equipment includes two major categories: Wet adsorption scrubbers (or wet scrubbers); Dry absorption scrubbers (or dry scrubbers).
    Wet scrubbers: As the name implies, wet scrubbers (also known as wet collectors) are devices which use a liquid fo...

  19. Novel dry forests in southwestern Puerto Rico

    Treesearch

    Sandra Molina Colón; Ariel E. Lugo; Olga Ramos

    2011-01-01

    We report results of new research on (1) community composition of novel subtropical dry forests developing on abandoned pastures and agricultural fields in both private and protected public lands and (2) seed germination and growth rates of plantings of native tree species on degraded soils. We found that novel dry forests were dominated by introduced species, which...

  20. Hot-dry-rock feasibility study

    SciTech Connect

    Not Available

    1981-08-01

    The hot-dry-rock project tasks are covered as follows: hot-dry-rock reservoir; generation facilities; water resources; transmission requirements; environmental issues; government and community institutional factors; leasing, ownership and management of facilities; regulations, permits, and laws; and financial considerations. (MHR)