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1

Capacity for Absorption of Water-Soluble Secondary Metabolites Greater in Birds than in Rodents  

E-print Network

Capacity for Absorption of Water-Soluble Secondary Metabolites Greater in Birds than in Rodents methodology to measure absorption of two radiolabeled, inert, neutral water-soluble probes that do). We also measured absorption of labeled 3-O-methyl-D-glucose (3OMD-glucose; Mr = 194.2 Da), which

Mladenoff, David

2

Determination of water absorption and water holding capacities of different soil mixtures with MINIDRAIN system to enhance the plant growth  

NASA Astrophysics Data System (ADS)

Soil water holding capacity is the amount of water that a given soil can hold against the force of gravity. Soil texture and organic matter are the key components that determine soil water holding capacity. Soils with smaller particle sizes, such as silt and clay have larger surface area can hold more water compared to sand which has large particle sizes which results in smaller surface area. A study report showed that 1% increase in soil humus will result in a 4% increase in stored soil water (Morris, 2004) and 1 part humus holds 4 parts of water (Wheeler and Ward, 1998). Therefore, the more humus that can be added to the soil, the greater the water holding capacity of the soil. As the level of organic matter increases in a soil, the water holding capacity also increases due to the affinity of organic matter for water. The water holding capacity of the soil is determined by the amount of water held in the soil sample vs. the dry weight of the sample. MINIDRAIN is a patented system made of geo-fabric (fleece) or combination of geosynthetics and humus. MINIDRAIN and vegetation nets developed by the company ÖKO-TEX (Linz, Austria) will improve the distribution of water and air in the soils, increase the growth of vegetation and reduce the soil erosion. Depending on the physical configuration, there are four different combinations of MINIDRAIN systems developed by ÖKO-TEX. a) Geotextile (fleece) strips of different sizes (e.g. 5x10x250 mm) b) Net formed strips (drainage nets) of different sizes c) Multilayer geotextile mats with humus, seeds or compost of different sizes (e.g. 10x30x200 mm) d) Multilayer geotextile net formed mats with humus, seeds or compost This paper describes the experimental results of the water absorption and water holding capacity of different forms of MINIDRAIN under different soil mixes. In this experiment, potting soil, coarse sand and LECA (Light weight clay aggregates) balls are mixed with different proportion of MINIDRAIN systems and the water absorption and water holding capacities are measured. A comparison of the results for an optimal combination of soil and MINIDRAIN system has also been made. The results show that, the soil mix with MINIDRAIN system with multilayer mats (with humus) have highest water absorption and water holding capacity among the tested soil mix combinations.

Sudan Acharya, Madhu; Rauchecker, Markus; Wu, Wei

2014-05-01

3

Capacity for Absorption of Water-Soluble Secondary Metabolites Greater in Birds than in Rodents  

PubMed Central

Plant secondary metabolites (SMs) are pervasive in animal foods and potentially influence feeding behavior, interspecies interactions, and the distribution and abundance of animals. Some of the major classes of naturally occurring SMs in plants include many water-soluble compounds in the molecular size range that could cross the intestinal epithelium via the paracellular space by diffusion or solvent drag. There are differences among species in paracellular permeability. Using Middle Eastern rodent and avian consumers of fruits containing SMs, we tested the hypothesis that avian species would have significantly higher paracellular permeability than rodent species. Permeability in intact animals was assessed using standard pharmacological methodology to measure absorption of two radiolabeled, inert, neutral water-soluble probes that do not interact with intestinal nutrient transporters, L-arabinose (Mr?=?150.1 Da) and lactulose (Mr?=?342.3 Da). We also measured absorption of labeled 3-O-methyl-D-glucose (3OMD-glucose; Mr?=?194.2 Da), which is a nonmetabolized analogue of D-glucose that is passively absorbed through the paracellular space but also transported across the enterocyte membranes. Most glucose was absorbed by all species, but arabinose fractional absorption (f) was nearly three times higher in birds (1.03±0.17, n?=?15 in two species) compared to rodents (0.37±0.06, n?=?10 in two species) (P<0.001). Surprisingly, the apparent rates of absorption in birds of arabinose exceeded those of 3OMD-glucose. Our findings are in agreement with previous work showing that the paracellular pathway is more prominent in birds relative to nonflying mammals, and suggests that birds may be challenged by greater absorption of water-soluble, dietary SMs. The increased expression of the paracellular pathway in birds hints at a tradeoff: the free energy birds gain by absorbing water-soluble nutrients passively may be offset by the metabolic demands placed on them to eliminate concomitantly absorbed SMs. PMID:22389702

Karasov, William H.; Caviedes-Vidal, Enrique; Bakken, Bradley Hartman; Izhaki, Ido; Samuni-Blank, Michal; Arad, Zeev

2012-01-01

4

Modification of water absorption capacity of a plastic based on bean protein using gamma irradiated starches as additives  

NASA Astrophysics Data System (ADS)

Some properties of a bean protein-starch plastic were modified by irradiation of the starch. Two kinds of starch from bean and cassava were irradiated with doses until 50 kGy before their inclusion in the composite. Water absorption of the resultant product was reduced by 36% and 60% in materials containing bean and cassava starch, respectively. A large decline in the elongation is observed till 10 kGy in both materials, while tensile strength diminished by 11% in the cassava composite.

Köber, E.; Gonzalez, M. E.; Gavioli, N.; Salmoral, E. M.

2007-01-01

5

Evaluation of an Absorption Heat Pump to Mitigate Plant Capacity Reduction Due to Ambient Temperature Rise for an Air-Cooled Ammonia and Water Cycle: Preprint  

SciTech Connect

Air-cooled geothermal plants suffer substantial decreases in generating capacity at increased ambient temperatures. As the ambient temperature rises by 50 F above a design value of 50 F, at low brine-resource temperatures, the decrease in generating capacity can be more than 50%. This decrease is caused primarily by increased condenser pressure. Using mixed-working fluids has recently drawn considerable attention for use in power cycles. Such cycles are more readily amenable to use of absorption ''heat pumps.'' For a system that uses ammonia and water as the mixed-working fluid, this paper evaluates using an absorption heat pump to reduce condenser backpressure. At high ambient temperatures, part of the turbine exhaust vapor is absorbed into a circulating mixed stream in an absorber in series with the main condenser. This steam is pumped up to a higher pressure and heated to strip the excess vapor, which is recondensed using an additional air-cooled condenser. The operating conditions are chosen to reconstitute this condensate back to the same concentration as drawn from the original system. We analyzed two power plants of nominal 1-megawatt capacity. The design resource temperatures were 250 F and 300 F. Ambient temperature was allowed to rise from a design value of 50 F to 100 F. The analyses indicate that using an absorption heat pump is feasible. For the 300 F resource, an increased brine flow of 30% resulted in a net power increase of 21%. For the 250 F resource, the increase was smaller. However, these results are highly plant- and equipment-specific because evaluations must be carried out at off-design conditions for the condenser. Such studies should be carried out for specific power plants that suffer most from increased ambient temperatures.

Bharathan, D.; Nix, G.

2001-08-06

6

Analyzing Water's Optical Absorption  

NASA Technical Reports Server (NTRS)

A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.

2002-01-01

7

Capacity sharing of water reservoirs  

NASA Astrophysics Data System (ADS)

The concept of a water use property right is developed which does not apply to water volumes as such but to a share of the capacity (not contents) of river storage reservoirs and their inflows. The shareholders can withdraw water from their share over time in accordance with their preferences for stability of water deliveries. The reservoir authority does not manage reservoir releases but keeps record of individual shareholder's withdrawals and net inflows to monitor the quantity of water in each shareholder's capacity share. A surplus of total reservoir contents over the sum of the contents of the individual shareholder's capacity shares will accrue over time. Two different criteria for its periodic distribution among shareholders are compared. A previous paper Dudley (this issue(b)) noted a loss of short-run economic efficiency as reservoir and farm management decision making become separated. This is largely overcome by capacity sharing which allows each user to integrate the management of their portion of the reservoir and their farming operations. The nonattenuated nature of the capacity sharing water rights also promotes long-run economic efficiency.

Dudley, Norman J.; Musgrave, Warren F.

1988-05-01

8

Pronounced energy absorption capacity of cellular bulk metallic glasses  

NASA Astrophysics Data System (ADS)

Cellular bulk metallic glasses (BMGs) with macroscopic cellular structures were designed and fabricated. The cellular BMGs exhibited remarkable energy absorption capacity as compared with reported BMG foams and honeycombs. The enhanced energy absorption capability is attributed to the large plastic bending of the struts, the blunting of the cracks, and the large plastic deformation at the nodes. This work shows that, in cellular BMGs, the macroscopic cellular structures are more efficient in dissipating mechanical energy than microscopic cellular structures, opening a window for developing energy absorption devices using BMGs.

Chen, S. H.; Chan, K. C.; Wu, F. F.; Xia, L.

2014-03-01

9

Evaluation of an Absorption Heat Pump to Mitigate Plant Capacity Reduction Due to Ambient Temperature Rise for an Air-Cooled Ammonia and Water Cycle: Preprint  

Microsoft Academic Search

Air-cooled geothermal plants suffer substantial decreases in generating capacity at increased ambient temperatures. As the ambient temperature rises by 50 F above a design value of 50 F, at low brine-resource temperatures, the decrease in generating capacity can be more than 50%. This decrease is caused primarily by increased condenser pressure. Using mixed-working fluids has recently drawn considerable attention for

D. Bharathan; G. Nix

2001-01-01

10

The effect of moisture-induced swelling on the absorption capacity of transversely isotropic  

E-print Network

; Swelling; Diffusion 1 Introduction When a polymer is exposed to a humid environment, it absorbs some water by diffusion, and this induces swelling in frequent cases. If this polymer is the matrix of a compositeThe effect of moisture-induced swelling on the absorption capacity of transversely isotropic

Paris-Sud XI, Université de

11

Absorptive capacity of Kuwait: domestic and international perspectives  

SciTech Connect

Kuwait is a small country with a small population and little industry to absorb the income from its oil exports. Dwindling internal investment opportunities had already presented the problems of surplus wealth before the emergence of OPEC in the 1970s and the resultant price hike in crude oil. The problem of absorptive capacity and its role in long-range planning have become more acute since. An overview of the economic, political, and social constraints confronting Kuwait's leaders provides insight into the structure and policies of the country and information on Kuwaiti relations with other Arab nations as well as with the rest of the world. Using a macroeconomic approach, the authors build a forecasting model to project future absorptive-capacity problems, and they provide optimistic solutions for the betterment of the entire region. 63 references, 3 figures, 48 tables.

El Mallakh, R.; Atta, J.K.

1981-01-01

12

Cognitive Distance, Absorptive Capacity and Group Rationality: A Simulation Study  

PubMed Central

We report the results of a simulation study in which we explore the joint effect of group absorptive capacity (as the average individual rationality of the group members) and cognitive distance (as the distance between the most rational group member and the rest of the group) on the emergence of collective rationality in groups. We start from empirical results reported in the literature on group rationality as collective group level competence and use data on real-life groups of four and five to validate a mathematical model. We then use this mathematical model to predict group level scores from a variety of possible group configurations (varying both in cognitive distance and average individual rationality). Our results show that both group competence and cognitive distance are necessary conditions for emergent group rationality. Group configurations, in which the groups become more rational than the most rational group member, are groups scoring low on cognitive distance and scoring high on absorptive capacity. PMID:25314132

Cur?eu, Petru Lucian; Krehel, Oleh; Evers, Joep H. M.; Muntean, Adrian

2014-01-01

13

Absorptive capacity and post-acquisition inventor productivity  

Microsoft Academic Search

Inventors often experience a low productivity after their company has been subject to a merger or acquisition (M&As). It is\\u000a of central managerial interest to identify factors facilitating the integration of new inventive staff and thereby counteracting\\u000a innovation declines after M&As. This paper provides empirical evidence into the role of acquiring firms’ absorptive capacity\\u000a for the post-merger patent productivity of

Katrin Hussinger

2010-01-01

14

Meet me halfway: research joint ventures and absorptive capacity  

Microsoft Academic Search

We propose a representation of a firm’s ‘effective’ R&D effort level that reflects how both its R&D approach and R&D budget influences its ability to realize spillovers from other firms’ R&D activity, i.e. its ‘absorptive capacity’, and generalizes the commonly employed representation. The ability to choose an R&D approach is accommodated by positing a three-stage game in which the choice

Morton I. Kamien; Israel Zang

2000-01-01

15

On the absorption capacity of the REDY cartridge.  

PubMed

The absorption capacity of the REDY cartridge was investigated exclusively by in vitro experiments. The maximum absorption capacity for urea, phosphate, creatinine, and urinc acid, was found to be respectively 55 g, more than 4 g (phosphorus), 10 g, and more than 7,5 g. The maximum absorption rates of the same substances were found to be 600-800 mg/min., more than 33 mg/min., more than 170 mg/min., and 13 mg/min. respectively. The ability of the cartridge to absorb urea was found to be practically unaffected by 2 mmol of copper and 7 mmol of zinc, and to be unaffected by supraphysiological concentrations of lithium. The amount of exchangeable cations was determined for three cartridges, and found to be 6100, 3800, and 7200 mmol. The cation exchanger was found to act as a buffer, giving the whole cartridge a buffering capacity of 0,6 mol. Of the layers of cation exchanger, anion exchanger, and activated charcoal, only the latter was found to be able to bind urea. PMID:935818

Christiansen, E

1976-01-01

16

The capacity for paracellular absorption in the insectivorous bat Tadarida brasiliensis.  

PubMed

Water-soluble nutrients are absorbed by the small intestine via transcellular and paracellular processes. The capacity for paracellular absorption seems greater in fliers than in nonfliers, although that conclusion rests mainly on a comparison of flying birds and nonflying mammals because only two frugivorous bat species have been studied. Furthermore, the bats studied so far were relatively large (>85 g, compared with most bat species which are <20 g) and were not insectivores (like about 70 % of bat species). We studied the small (11 g) insectivorous bat Tadarida brasiliensis and tested the prediction that the capacity for paracellular absorption would be as high as in the other bat and avian species studied so far, well above that in terrestrial, nonflying mammals. Using standard pharmacokinetic technique, we measured the extent of absorption (fractional absorption = f) of inert carbohydrate probes: L-arabinose (MM = 150.13) absorbed exclusively by paracellular route and 3OMD-glucose (MM = 194) absorbed both paracellularly and transcellularly. As predicted, the capacity of paracellular absorption in this insectivorous bat was high (L-arabinose f = 1.03 ± 0.14) as in other frugivorous bats and small birds. Absorption of 3OMD-glucose was also complete (f = 1.09 ± 0.17), but >80 % was accounted for by paracellular absorption. We conclude that passive paracellular absorption of molecules of the size of amino acids and glucose is extensive in this bat and, generally in bats, significantly higher than that in nonflying mammals, although the exact extent can be somewhat lower or higher depending on molecule size, polarity and charge. PMID:22872186

Fasulo, Verónica; Zhang, ZhiQiang; Chediack, Juan G; Cid, Fabricio D; Karasov, William H; Caviedes-Vidal, Enrique

2013-02-01

17

Protective Capacity and Absorptive Capacity: Managing the Balance between Retention and Creation of Knowledge-Based Resources  

ERIC Educational Resources Information Center

Purpose: In order to understand the pros and cons of an open organization regarding the flow of knowledge between firms, this paper introduces the concept of "protective capacity". The purpose of the paper is to elaborate the concept of "protective capacity" especially in relation to absorptive capacity, by presenting a number of propositions.…

Andersen, Jim

2012-01-01

18

Managing Potential and Realized Absorptive Capacity: How do Organizational Antecedents matter?  

Microsoft Academic Search

This study explores how organizational antecedents affect potential and realized absorptive capacity. Our study identifies differential effects for both components of absorptive capacity. Results indicate that organizational mechanisms associated with coordination capabilities (i.e. cross-functional interfaces, participation in decision-making, and job rotation) primarily enhance a unit’s potential absorptive capacity. Organizational mechanisms associated with socialization capabilities (i.e. connectedness and socialization tactics) primarily

JUSTIN J. P. JANSEN; FRANS A. J. VAN DEN BOSCH; HENK W. VOLBERDA

2005-01-01

19

d-Xylose absorption test: A tool for the assessment of the effect of anticoccidials on the intestinal absorptive capacity of broilers during experimental coccidiosis  

Microsoft Academic Search

Coccidiosis in chickens causes intestinal mucosal lesions and disrupts its integrity leading to a disturbance in absorption of dietary components. The d-xylose absorption test is a sensitive tool of measuring the absorption capacity of the intestine in diseased chickens. In an experiment on broilers, the influence of different anticoccidials on the intestinal absorption capacity of the birds challenged with experimental

B. Mansoori; H. Nodeh; M. Modirsanei; S. Rahbari; P. Aparnak

2009-01-01

20

Water storage capacity in the Earth's upper mantle  

NASA Astrophysics Data System (ADS)

While it is well accepted that significant amounts of water can be stored as hydroxyl in nominally anhydrous minerals (NAMs) of the mantle, the storage capacity of the mantle remains unknown because the simultaneous effects of pressure, temperature and composition have never been investigated in the laboratory. The majority of studies has concentrated on the study of single phases and have established very important basis for our understanding of water incorporation in minerals. It has been shown that the solubility of water in NAMs increases with increasing pressure and water fugacity. The effect of temperature is more complicated. At low pressures water solubility in olivine increases with temperature, whereas at high pressures it follows a bell-shaped curve and decreases with increasing temperature above a critical temperature which corresponds to the onset of wet melting around 1100-1200°C. Concerning the effect of composition, it has been shown that water solubility in olivine increases with increasing iron content at 0.3 GPa. But this is contradicted by recent reports at high pressures of 8 to 14 GPa. Silica activity is an important parameter at low pressure, which could affect the OH infrared absorption spectra of olivine and then potentially help in diagnosis of the environment in which olivine formed. However, these spectral distinctions disappear at high pressures. Also, the correlation of some hydroxyl absorption bands in infrared spectra of olivine with aliovalent impurities such as Fe3+, Al3+ and Ti4+ vanishes as water fugacity increases. This is logical since olivine does not incorporate much impurities, water fugacity will be the strongest effect with increasing pressure. Thus it appears that in olivine many behaviours due to environmental conditions measured at low pressures (< 3 GPa) are not occurring at high pressures, suggesting that extrapolation of solubility laws established at low pressures would yield misleading estimates at high pressures. A review of the state-of the-art results will be presented as well as a model of water storage capacity in the upper mantle.

Bolfan-Casanova, Nathalie

2010-05-01

21

Atmospheric absorption of terahertz radiation and water vapor continuum effects  

E-print Network

Atmospheric absorption of terahertz radiation and water vapor continuum effects David M. Slocum a vapor Absorption Continuum Terahertz Spectroscopy a b s t r a c t The water vapor continuum absorption. The absorption coefficient as a function of frequency was determined and compared with theoretical predictions

Massachusetts at Lowell, University of

22

Atmospheric absorption of terahertz radiation and water vapor continuum effects  

E-print Network

Atmospheric absorption of terahertz radiation and water vapor continuum effects David M. Slocum a April 2013 Keywords: Water vapor Absorption Continuum Terahertz Spectroscopy a b s t r a c t The water vapor continuum absorption spectrum was investigated using Fourier Trans- form Spectroscopy

Massachusetts at Lowell, University of

23

Absorption coefficient instrument for turbid natural waters  

NASA Technical Reports Server (NTRS)

The paper presents an instrument that directly measures multispectral absorption coefficient of turbid natural water. Attention is given to the design, which is shown to incorporate methods for the compensation of variation in the internal light source intensity, correction of the spectrally dependent nature of the optical elements, and correction for variation in the background light level. In addition, when used in conjunction with a spectrally matched total attenuation instrument, the spectrally dependent scattering coefficient can also be derived. Finally, it is reported that systematic errors associated with multiple scattering have been estimated using Monte Carlo techniques.

Friedman, E.; Cherdak, A.; Poole, L.; Houghton, W.

1980-01-01

24

New V-based alloys with high protium absorption and desorption capacity  

Microsoft Academic Search

The hydrogen absorption properties of V–Zr–Ti–M(M=Fe, Mn, Ni) alloys were examined in order to develop the alloys with high hydrogen capacity. It was found that the best composition among the studied alloys is the V–Zr–Ti–Ni system. A suitable amount of the vanadium in the V–Zr–Ti–Ni system was studied in correlation with its hydrogen absorption properties, and turned out to be

T Kuriiwa; T Tamura; T Amemiya; T Fuda; A Kamegawa; H Takamura; M Okada

1999-01-01

25

Technology management capability and new product development performance: The mediating role of absorptive capacity  

Microsoft Academic Search

New product development and technology management are both of significance in obtaining firms' competitive advantage. By proposing a conceptual outline for a general model that explains the relationship between technology management capability and new product development performance, we examine the impact of technology management capability on new product development performance, as well as the moderating effects of absorptive capacity on

Weiwei Wu; Ying Yang; Qiang Deng; Bo Yu

2010-01-01

26

UNDER THE TIP OF THE ICEBERG: ABSORPTIVE CAPACITY, ENVIRONMENTAL STRATEGY, AND COMPETITIVE  

E-print Network

1 UNDER THE TIP OF THE ICEBERG: ABSORPTIVE CAPACITY, ENVIRONMENTAL STRATEGY, AND COMPETITIVE. If this is true, are environmental strategies just the tip of the organizational iceberg? By focusing solely that we need to look beneath the surface, under the tip of the organizational iceberg, in order to get

Delmas, Magali

27

Measurement of krypton-85 in water by absorption in polycarbonates  

Microsoft Academic Search

This article describes a method for quantitative measurements of Kr85 in water by absorption in polycarbonates. The method is based on exposure of polycarbonate samples in water and uses the high absorption ability to noble gases of some polycarbonates like Makrofol® and Makrolon® for sampling Kr85 from the water. After the exposure, the radiation emitted from the samples is measured

K. Mitev; D. Pressyanov; I. Dimitrova; S. Georgiev; T. Boshkova; V. Zhivkova

2009-01-01

28

Water-lithium bromide double-effect absorption cooling analysis. Final report  

SciTech Connect

This investigation involved the development of a numerical model for the transient simulation of the double-effect, water-lithium bromide absorption cooling machine, and the use of the model to determine the effect of the various design and input variables on the absorption unit performance. The performance parameters considered were coefficient of performance and cooling capacity. The sensitivity analysis was performed by selecting a nominal condition and determining performance sensitivity for each variable with others held constant. The variables considered in the study include source hot water, cooling water, and chilled water temperatures; source hot water, cooling water, and chilled water flow rates; solution circulation rate; heat exchanger areas; pressure drop between evaporator and absorber; solution pump characteristics; and refrigerant flow control methods. The performance sensitivity study indicated in particular that the distribution of heat exchanger area among the various (seven) heat exchange components is a very important design consideration. Moreover, it indicated that the method of flow control of the first effect refrigerant vapor through the second effect is a critical design feature when absorption units operate over a significant range of cooling capacity. The model was used to predict the performance of the Trane absorption unit with fairly good accuracy. The dynamic model should be valuable as a design tool for developing new absorption machines or modifying current machines to make them optimal based on current and future energy costs.

Vliet, G.C.; Lawson, M.B.; Lithgow, R.A.

1980-12-01

29

Economic performance of water storage capacity expansion for food security  

NASA Astrophysics Data System (ADS)

SummaryContinued climate variability, population growth, and rising food prices present ongoing challenges for achieving food and water security in poor countries that lack adequate water infrastructure. Undeveloped storage infrastructure presents a special challenge in northern Afghanistan, where food security is undermined by highly variable water supplies, inefficient water allocation rules, and a damaged irrigation system due three decades of war and conflict. Little peer-reviewed research to date has analyzed the economic benefits of water storage capacity expansions as a mechanism to sustain food security over long periods of variable climate and growing food demands needed to feed growing populations. This paper develops and applies an integrated water resources management framework that analyzes impacts of storage capacity expansions for sustaining farm income and food security in the face of highly fluctuating water supplies. Findings illustrate that in Afghanistan's Balkh Basin, total farm income and food security from crop irrigation increase, but at a declining rate as water storage capacity increases from zero to an amount equal to six times the basin's long term water supply. Total farm income increases by 21%, 41%, and 42% for small, medium, and large reservoir capacity, respectively, compared to the existing irrigation system unassisted by reservoir storage capacity. Results provide a framework to target water infrastructure investments that improve food security for river basins in the world's dry regions with low existing storage capacity that face ongoing climate variability and increased demands for food security for growing populations.

Gohar, Abdelaziz A.; Ward, Frank A.; Amer, Saud A.

2013-03-01

30

Absorptive capacity, regional cooperation, and industrialization in the Arab states of the Gulf. [Kuwait, Qatar, and the United Arab Emirates  

Microsoft Academic Search

The long-term impact of the new oil prices on the absorptive capacity of the oil-based economies has been analyzed from the standpoint of the domestic economics of these countries. This paper extends the concept of absorptive capacity to incorporate the effects of regional integration and industrialization in the Arab states of the Gulf. The discussion is organized into four parts.

M. Kadhim; B. Poulson

2009-01-01

31

The implementation of a global fund grant in Lesotho: applying a framework on knowledge absorptive capacity.  

PubMed

One of the biggest challenges in scaling up health interventions in sub-Saharan Africa for government recipients is to effectively manage the rapid influx of aid from different donors, each with its own requirements and conditions. However, there is little empirical evidence on how governments absorb knowledge from new donors in order to satisfy their requirements. This case study applies Cuellar and Gallivan's (2006) framework on knowledge absorptive capacity (AC) to illustrate how recipient government organisations in Lesotho identified, assimilated and utilised knowledge on how to meet the disbursement and reporting requirements of Lesotho's Round 5 grant from the Global Fund to Fight AIDS, TB and Malaria (Global Fund). In-depth topic guided interviews with 22 respondents and document reviews were conducted between July 2008 and February 2009. Analysis focused on six organisational determinants that affect an organisation's absorptive capacity: prior-related knowledge, combinative capabilities, motivation, organisational structure, cultural match, and communication channels. Absorptive capacity was mostly evident at the level of the Principal Recipient, the Ministry of Finance, who established a new organisational unit to meet the requirements of Global Fund Grants, while the level of AC was less advanced among the Ministry of Health (Sub-Recipient) and district level implementers. Recipient organisations can increase their absorptive capacity, not only through prior knowledge of donor requirements, but also by deliberately changing their organisational form and through combinative capabilities. The study also revealed how vulnerable African governments are to loss of staff capacity. The application of organisational theory to analyse the interactions of donor agencies with public and non-public country stakeholders illustrates the complexity of the environment that aid recipient governments have to manage. PMID:21907474

Biesma, Regien; Makoa, Elsie; Mpemi, Regina; Tsekoa, Lineo; Odonkor, Philip; Brugha, Ruairi

2012-02-01

32

Water holding capacities of fly ashes: Effect of size fractionation  

SciTech Connect

Water holding capacities of fly ashes from different thermal power plants in Eastern India have been compared. Moreover, the effect of size fractionation (sieving) on the water holding capacities has also been determined. The desorption rate of water held by the fly ash fractions at ambient temperature (25-30{sup o}C) has been investigated. The effect of mixing various size fractions of fly ash in increasing the water holding capacities of fly ash has been studied. It is observed that the fly ash obtained from a thermal power plant working on stoker-fired combustor has the highest water holding capacity, followed by the one that works on pulverized fuel combustor. Fly ash collected from super thermal power plant has the least water holding capacity (40.7%). The coarser size fractions of fly ashes in general have higher water holding capacities than the finer ones. An attempt has been made to correlate the results obtained, with the potential use in agriculture.

Sarkar, A.; Rano, R. [Indian School of Mines, Dhanbad (India). Dept. of Applied Chemistry

2007-07-01

33

GASTROINTESTINAL ABSORPTION OF SOLUBLE URANIUM FROM DRINKING WATER  

EPA Science Inventory

The manuscript describes results of an experiment to determine the gastrointestinal absorption of uranium from drinking water in 12 health adults. Most of the uranium ingested was excreted in feces in the first 2 days following ingestion of the water. The absorption was the same ...

34

Effect of water absorption on pollen adhesion.  

PubMed

Pollens possess a thin liquid coating, pollenkitt, which plays a major role in adhesion by forming capillary menisci at interfaces. Unfortunately, the influence of humidity on pollenkitt properties and capillary adhesion is unknown. Because humidity varies widely in the environment, the answers have important implications for better understanding plant reproduction, allergy and asthma, and pollen as atmospheric condensation nuclei. Here, pollenkitt-mediated adhesion of sunflower pollen to hydrophilic and hydrophobic surfaces was measured as a function of humidity. The results quantify for the first time the significant water absorption of pollenkitt and the resulting complex dependence of adhesion on humidity. On hydrophilic Si, adhesion increased with increasing RH for pollens with or without pollenkitt, up to 200nN at 70% RH. In contrast, on hydrophobic PS, adhesion of pollenkitt-free pollen is independent of RH. Surprisingly, when pollenkitt was present adhesion forces on hydrophobic PS first increased with RH up to a maximum value at 35% RH (?160nN), and then decreased with further increases in RH. Independent measurement of pollenkitt properties is used with models of capillary adhesion to show that humidity-dependent changes in pollenkitt wetting and viscosity are responsible for this complex adhesion behavior. PMID:25524008

Lin, Haisheng; Lizarraga, Leonardo; Bottomley, Lawrence A; Carson Meredith, J

2015-03-15

35

Absorptive capacity and a failed cross-border M&A  

Microsoft Academic Search

Purpose – Chinese companies are increasingly using cross-border mergers and acquisitions (M&A) to source knowledge or strategic assets. For many, global acquisitions have proven to be highly problematic and value-destroying. The purpose of this paper is to address this critical acquisition failure issue from an absorptive capacity perspective. Design\\/methodology\\/approach – Guided by the framework that focuses on how acquiring a

Ping Deng

2010-01-01

36

Heat capacity of water: A signature of nuclear quantum effects  

NASA Astrophysics Data System (ADS)

In this note we present results for the heat capacity at constant pressure for the TIP4PQ/2005 model, as obtained from path-integral simulations. The model does a rather good job of describing both the heat capacity of ice Ih and of liquid water. Classical simulations using the TIP4P/2005, TIP3P, TIP4P, TIP4P-Ew, simple point charge/extended, and TIP5P models are unable to reproduce the heat capacity of water. Given that classical simulations do not satisfy the third law of thermodynamics, one would expect such a failure at low temperatures. However, it seems that for water, nuclear quantum effects influence the heat capacities all the way up to room temperature. The failure of classical simulations to reproduce Cp points to the necessity of incorporating nuclear quantum effects to describe this property accurately.

Vega, C.; Conde, M. M.; McBride, C.; Abascal, J. L. F.; Noya, E. G.; Ramirez, R.; Sesé, L. M.

2010-01-01

37

Fuzzy Comprehensive Evaluation for Carrying Capacity of Regional Water Resources  

Microsoft Academic Search

Evaluation of regional water resources capacity provides a scientific basis for further water resources utilization and social\\u000a economic sustainable development. This paper mainly studied on the case of Lanzhou City located in the western China. By using\\u000a the method of fuzzy comprehensive evaluation and basing on the historical datum of 40 years, this paper evaluated the current\\u000a situation of water resource

Li Gong; Chunling Jin

2009-01-01

38

Isochoric heat capacity of an n-hexane + water system  

NASA Astrophysics Data System (ADS)

The isochoric heat capacity of an n-hexane + water system at water contents of 0.121, 0.166, 0.2, 0.234, 0.256, and 0.3 mole fraction is studied along different isochors at different temperatures in the 140 to 550 kg/m3 range of densities using a high-temperature adiabatic calorimeter designed at the Amirkhanov Institute of Physics. The tabulated values of isochoric heat capacity C v, x are presented for an H2O concentration of 0.3 mole fraction. The curves of liquid-liquid and liquid-gas phase equilibria are constructed.

Bezgomonova, E. I.; Saidov, S. M.; Stepanov, G. V.

2015-01-01

39

Climate Adaptation Capacity for Conventional Drinking Water Treatment Facilities  

NASA Astrophysics Data System (ADS)

Water supplies are vulnerable to a host of climate- and weather-related stressors such as droughts, intense storms/flooding, snowpack depletion, sea level changes, and consequences from fires, landslides, and excessive heat or cold. Surface water resources (lakes, reservoirs, rivers, and streams) are especially susceptible to weather-induced changes in water availability and quality. The risks to groundwater systems may also be significant. Typically, water treatment facilities are designed with an underlying assumption that water quality from a given source is relatively predictable based on historical data. However, increasing evidence of the lack of stationarity is raising questions about the validity of traditional design assumptions, particularly since the service life of many facilities can exceed fifty years. Given that there are over 150,000 public water systems in the US that deliver drinking water to over 300 million people every day, it is important to evaluate the capacity for adapting to the impacts of a changing climate. Climate and weather can induce or amplify changes in physical, chemical, and biological water quality, reaction rates, the extent of water-sediment-air interactions, and also impact the performance of treatment technologies. The specific impacts depend on the watershed characteristics and local hydrological and land-use factors. Water quality responses can be transient, such as erosion-induced increases in sediment and runoff. Longer-term impacts include changes in the frequency and intensity of algal blooms, gradual changes in the nature and concentration of dissolved organic matter, dissolved solids, and modulation of the microbiological community structure, sources and survival of pathogens. In addition, waterborne contaminants associated with municipal, industrial, and agricultural activities can also impact water quality. This presentation evaluates relationships between climate and weather induced water quality variability and the capacity of treatment facilities and supporting water infrastructure to deliver safe drinking water consistently and reliably. Simulation models of water treatment facilities are used to evaluate the outcome of specific source water quality scenarios on treatment system performance and reliability. Modeling results are used to evaluate the process and operational capacity to respond to transient water quality changes and adapt to longer-term variability in water quality and availability. In some cases, changes in temperature and mineral content serve to improve the overall treatment performance. In addition, the integration of microbially enhanced treatment systems such as biological filtration can provide additional capacity. Conversely, changes in the nutrient and temperature dynamics can trigger algal and cyanobacterial blooms that can impair performance. Research needs are identified and the importance of developing more integrated modeling systems is highlighted.

Levine, A.; Goodrich, J.; Yang, J.

2013-12-01

40

Absorption of water and lubricating oils into porous nylon  

NASA Technical Reports Server (NTRS)

Oil and water absorption from air into sintered porous nylon can be described by infiltration into the pores of the material. This process can be modeled by a diffusion-like mechanism. For water absorption, we find a formal diffusion coefficient of 1.5 x 10(exp -4)sq cm/min when the nylon is initially dry. The diffusion coefficient is 4 x 10(exp -6)sq cm/min when the nylon is oil-impregnated prior to air exposure. In a 52% RH atmosphere, dry nylon absorbs 3% w/w water, and oil-impregnated nylon absorbs 0.6% w/w water. For oil absorption there are three steps: (1) surface absorption and infiltration into (2) larger and (3) smaller pores. Surface absorption is too fast to be measured in these experiments. The diffusion coefficient for the second step is 6 x 10(exp -4)sq cm/min for SRG-60 oil into dry nylon and 4 x 10(exp -4)sq cm/min for air-equilibrated nylon. The diffusion coefficient for the third step is about 1 x 10(exp -6)sq cm/min for both cases. The total amount of oil absorbed is 31% w/w. The interaction between water and nylon is not as strong as that between water and cotton-phenolic: oil can replace water, and only a small amount of water can enter previously oil-impregnated nylon.

Bertrand, P. A.

1995-01-01

41

The environmental actions of firms: examining the role of spillovers, networks and absorptive capacity.  

PubMed

In the light of climate uncertainty and growing concern for the natural environment, an increasingly important aspect of global business is the environmental behaviour of firms. In this paper we consider the factors that influence firms' environmental actions (EAs). Our study of Argentinean firms concentrates on measures of environmental spillovers, informal and formal networks and absorptive capacity by testing four related hypotheses. We find that foreign-owned firms, large firms and those with a greater capacity to assimilate new environmental technologies are more likely to adopt EAs. We also show that formal and informal networks aid the adoption of EAs in the presence of traditional firm-level spillovers. Finally, we show that foreign-owned firms have different motives to domestic firms for undertaking EAs. PMID:25242544

Albornoz, Facundo; Cole, Matthew A; Elliott, Robert J R; Ercolani, Marco G

2014-12-15

42

Absorptive removal of biomass tar using water and oily materials.  

PubMed

Water is the most common choice of absorption medium selected in many gasification systems. Because of poor solubility of tar in water, hydrophobic absorbents (diesel fuel, biodiesel fuel, vegetable oil, and engine oil) were studied on their absorption efficiency of biomass tar and compared with water. The results showed that only 31.8% of gravimetric tar was removed by the water scrubber, whereas the highest removal of gravimetric tar was obtained by a vegetable oil scrubber with a removal efficiency of 60.4%. When focusing on light PAH tar removal, the absorption efficiency can be ranked in the following order; diesel fuel>vegetable oil>biodiesel fuel>engine oil>water. On the other hand, an increase in gravimetric tar was observed for diesel fuel and biodiesel fuel scrubbers because of their easy evaporation. Therefore, the vegetable oil is recommended as the best absorbent to be used in gasification systems. PMID:20801021

Phuphuakrat, Thana; Namioka, Tomoaki; Yoshikawa, Kunio

2011-01-01

43

Numerical simulation and performance assessment of a low capacity solar assisted absorption heat pump coupled with a sub-floor system  

Microsoft Academic Search

A prototype low capacity (10kW) single stage Li–Br absorption heat pump (AHP), suitable for residential and small building applications has been developed as a collaborative result between various European research institutes and industries. The primary heat source for the AHP is supplied from flat plate solar collectors and the hot\\/chilled water from the unit is delivered to a floor heating\\/cooling

A. A. Argiriou; C. A. Balaras; S. Kontoyiannidis; E. Michel

2005-01-01

44

30 CFR 75.1107-7 - Water spray devices; capacity; water supply; minimum requirements.  

Code of Federal Regulations, 2010 CFR

...HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Fire Protection Fire Suppression Devices and Fire-Resistant Hydraulic Fluids on Underground Equipment § 75.1107-7 Water spray devices; capacity; water supply; minimum...

2010-07-01

45

Ethanol and water capacities of alcohols: a molecular dynamics study  

Technology Transfer Automated Retrieval System (TEKTRAN)

The extended hydrogen bond networks formed by alcohols are good indicators of their capacities to hold water. Results from molecular dynamics simulations on 24 linear alcohol isomers containing from 6 to 12 carbon atoms show the effects of the hydroxyl location on bulk hydrogen-bonded structures. ...

46

Characteristics of Nasal-Associated Lymphoid Tissue (NALT) and Nasal Absorption Capacity in Chicken  

PubMed Central

As the main mucosal immune inductive site of nasal cavity, nasal-associated lymphoid tissue (NALT) plays an important role in both antigen recognition and immune activation after intranasal immunization. However, the efficiency of intranasal vaccines is commonly restricted by the insufficient intake of antigen by the nasal mucosa, resulting from the nasal mucosal barrier and the nasal mucociliary clearance. The distribution of NALT and the characteristic of nasal cavity have already been described in humans and many laboratory rodents, while data about poultry are scarce. For this purpose, histological sections of the chicken nasal cavities were used to examine the anatomical structure and histological characteristics of nasal cavity. Besides, the absorptive capacity of chicken nasal mucosa was also studied using the materials with different particle size. Results showed that the NALT of chicken was located on the bottom of nasal septum and both sides of choanal cleft, which mainly consisted of second lymphoid follicle. A large number of lymphocytes were distributed under the mucosal epithelium of inferior nasal meatus. In addition, there were also diffuse lymphoid tissues located under the epithelium of the concha nasalis media and the walls of nasal cavity. The results of absorption experiment showed that the chicken nasal mucosa was capable to absorb trypan blue, OVA, and fluorescent latex particles. Inactivated avian influenza virus (IAIV) could be taken up by chicken nasal mucosa except for the stratified squamous epithelium sites located on the forepart of nasal cavity. The intake of IAIV by NALT was greater than that of the nasal mucosa covering on non-lymphoid tissue, which could be further enhanced after intranasal inoculation combined with sodium cholate or CpG DNA. The study on NALT and nasal absorptive capacity will be benefit for further understanding of immune mechanisms after nasal vaccination and development of nasal vaccines for poultry. PMID:24391892

Kang, Haihong; Yan, Mengfei; Yu, Qinghua; Yang, Qian

2013-01-01

47

Measurement of krypton-85 in water by absorption in polycarbonates  

NASA Astrophysics Data System (ADS)

This article describes a method for quantitative measurements of Kr85 in water by absorption in polycarbonates. The method is based on exposure of polycarbonate samples in water and uses the high absorption ability to noble gases of some polycarbonates like Makrofol® and Makrolon® for sampling Kr85 from the water. After the exposure, the radiation emitted from the samples is measured by gross beta counting or gamma spectrometry. The results from the conducted experiments demonstrate a very good linear correlation between the measured signal and the activity concentration of Kr85 in the water. A possible practical application of the method is to monitor Kr85 concentration in water in at-reactor pools and wet spent fuel storage facilities.

Mitev, K.; Pressyanov, D.; Dimitrova, I.; Georgiev, S.; Boshkova, T.; Zhivkova, V.

2009-05-01

48

Determination of fixed water in rocks by infrared absorption  

USGS Publications Warehouse

An infrared absorption technique has been developed for the quantitative determination of "fixed water" (H2O+) in rocks. Potassium bromide disks containing 2-mg samples are scanned in the 3-??m spectral region and absorption at 2.96 ??m is determined. Although the exact nature of this peak is not known, other than that it is caused by an interaction between the potassium bromide and hydroxyl groups and water, it can be used for quantitative analysis. Rock samples, other than those containing significant percentages of clay minerals, can be analyzed with a standard deviation of 0.26%.

Breger, I.A.; Chandler, J.C.

1969-01-01

49

Ground water applications of the heat capacity mapping mission  

NASA Technical Reports Server (NTRS)

The paper discusses the ground water portion of a hydrologic investigation of eastern South Dakota using data from the Heat Capacity Mapping Mission (HCMM) satellite. The satellite carries a two-channel radiometer (0.5-1.1 and 10.5-12.5 microns) in a sun synchronous orbit and collects data at approximately 0230 and 1330 local standard time with repeat coverage of 5 to 16 days depending on latitude. It is shown that HCMM data acquired at appropriate periods of the diurnal and annual temperature cycle can provide useful information on shallow ground water.

Heilman, J. L.; Moore, D. G.

1981-01-01

50

Absorptive Capacity as a Guiding Concept for Effective Public Sector Management and Conservation of Freshwater Ecosystems  

NASA Astrophysics Data System (ADS)

The ability of an organisation to recognise the value of new external information, acquire it, assimilate it, transform, and exploit it, namely its absorptive capacity (AC), has been much researched in the context of commercial organisations and even applied to national innovation. This paper considers four key AC-related concepts and their relevance to public sector organisations with mandates to manage and conserve freshwater ecosystems for the common good. The concepts are the importance of in-house prior related knowledge, the importance of informal knowledge transfer, the need for motivation and intensity of effort, and the importance of gatekeepers. These concepts are used to synthesise guidance for a way forward in respect of such freshwater management and conservation, using the imminent release of a specific scientific conservation planning and management tool in South Africa as a case study. The tool comprises a comprehensive series of maps that depict national freshwater ecosystem priority areas for South Africa. Insights for implementing agencies relate to maintaining an internal science, rather than research capacity; making unpublished and especially tacit knowledge available through informal knowledge transfer; not underestimating the importance of intensity of effort required to create AC, driven by focussed motivation; and the potential use of a gatekeeper at national level (external to the implementing organisations), possibly playing a more general `bridging' role, and multiple internal (organisational) gatekeepers playing the more limited role of `knowledge translators'. The role of AC as a unifying framework is also proposed.

Murray, K.; Roux, D. J.; Nel, J. L.; Driver, A.; Freimund, W.

2011-05-01

51

Absorptive capacity as a guiding concept for effective public sector management and conservation of freshwater ecosystems.  

PubMed

The ability of an organisation to recognise the value of new external information, acquire it, assimilate it, transform, and exploit it, namely its absorptive capacity (AC), has been much researched in the context of commercial organisations and even applied to national innovation. This paper considers four key AC-related concepts and their relevance to public sector organisations with mandates to manage and conserve freshwater ecosystems for the common good. The concepts are the importance of in-house prior related knowledge, the importance of informal knowledge transfer, the need for motivation and intensity of effort, and the importance of gatekeepers. These concepts are used to synthesise guidance for a way forward in respect of such freshwater management and conservation, using the imminent release of a specific scientific conservation planning and management tool in South Africa as a case study. The tool comprises a comprehensive series of maps that depict national freshwater ecosystem priority areas for South Africa. Insights for implementing agencies relate to maintaining an internal science, rather than research capacity; making unpublished and especially tacit knowledge available through informal knowledge transfer; not underestimating the importance of intensity of effort required to create AC, driven by focussed motivation; and the potential use of a gatekeeper at national level (external to the implementing organisations), possibly playing a more general 'bridging' role, and multiple internal (organisational) gatekeepers playing the more limited role of 'knowledge translators'. The role of AC as a unifying framework is also proposed. PMID:21431779

Murray, K; Roux, D J; Nel, J L; Driver, A; Freimund, W

2011-05-01

52

Water vapor continuum: Whether collision-induced absorption is involved?  

NASA Astrophysics Data System (ADS)

In a series of recent publications, the idea is pursued to shed a new light on the theory of the water vapor continuum absorption invoking the mechanism of collision-induced absorption. In the opinion of the present author, a portion of theoretical suggestions on this subject is biased and may thus lead to untenable conclusions about the nature of the continuum. The most typical drawback consists of improper consideration of statistics in the ensemble of interacting monomers that lead to embedding incorrect statistical weights to various types of molecular pairs which can form. The current note aims at clarifying the term “collision-induced absorption” in order to avoid incongruity in understanding the nature of the water vapor continuum.

Vigasin, A. A.

2014-11-01

53

Intestinal water absorption from select carbohydrate solutions in humans.  

PubMed

Eight men positioned a triple-lumen tube in the duodenojejunum. By use of segmental perfusion, 2, 4, 6, or 8% solutions of glucose (111-444 mM), sucrose (55-233 mM), a maltodextrin [17-67 mM, avg. chain length = 7 glucose units (7G)], or a corn syrup solid [40-160 mM, avg. chain length = 3 glucose units (3G)] were perfused at 15 ml/min for 70 min after a 30-min equilibration period. All solutions were made isotonic with NaCl, except 6 and 8% glucose solutions, which were hypertonic. An isotonic NaCl solution was perfused as control. Water absorption (range: 9-15 ml.h-1.cm-1) did not differ for the 2, 4, and 6% CHO solutions but was greater (P < 0.05) than absorption from control (3.0 +/- 2.2 ml.h-1.cm-1). The 8% glucose and 3G solutions reduced (P < 0.05) net water flux compared with their 2, 4, and 6% solutions, but 8% sucrose and 8% 7G solutions promoted water absorption equivalent to lower CHO concentrations. Water absorption was independent of [Na+] in the original solution. In the test segment, 1) Na+ flux correlated with net water flux (r = 0.72, P < 0.01), K+ (r = 0.78, P < 0.01), and [Na+] (r = 0.68, P < 0.001); 2) Na+ absorption occurred at luminal [Na+] as low as 50 mM; 3) glucose transport increased linearly over the luminal concentration range of 40-180 mM; and 4) net water flux was similar over a range of glucose-to-Na+ concentration ratios of 0.4:1 to 3.5:1.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1474096

Gisolfi, C V; Summers, R W; Schedl, H P; Bleiler, T L

1992-11-01

54

Pulsed photoacoustic calibration of a differential absorption water vapor lidar  

Microsoft Academic Search

We have designed and constructed a photoacoustic (PA) cell to be used for wavelength calibration in a water vapor differential absorption lidar (DIAL) system. This system will be used to remotely determine atmospheric H2O16 concentrations. The accuracy of these measurements depends critically on the ability to tune to and detune from lines in the water vapor spectrum. Specifically, the signal-to-noise

Anthony V. Dentamaro; Phan D. Dao

2003-01-01

55

Absorption characteristics of optically complex inland waters: Implications for water optical classification  

NASA Astrophysics Data System (ADS)

Multiple bio-optical measurements were conducted in inland waters of China, including Lake Taihu [spring and autumn], Lake Chaohu, Lake Dianchi, and Three Gorges Reservoirs. The variations in the absorption characteristics of chromophoric dissolved organic matter (CDOM), phytoplankton, and non-algal particles (NAP) and their relative contributions to total absorption among these waters were analyzed. The obtained results indicated that these areas are representative of the optically complex inland waters characterized by strong regional variations of their absorption properties. By means of the relative contributions of NAP and phytoplankton to the total water absorption at 550 and 675 nm, these waters were classified into three optical water types, each one having specific biogeochemical and optical properties. Two of the types were distinct and corresponded to waters that are optically controlled by NAP (Type I) and dominated by phytoplankton (Type III). Type II was related to relatively optically mixed waters where the absorption properties are controlled by NAP and phytoplankton. Additionally, the differences in remote-sensing reflectance (Rrs) spectra among the three classified water types were clarified to establish optical criteria for identifying these water types. On this basis, the classification criteria for MERIS images were developed, which allowed one to cluster every Rrs spectrum into one of the three water types by comparing the values from band 6, band 8, and band 9 of MERIS images. The proposed criteria were subsequently conducted to map the water types of Lake Taihu using MERIS images.

Shi, Kun; Li, Yunmei; Li, Lin; Lu, Heng

2013-06-01

56

A Novel Absorption Cycle for Combined Water Heating, Dehumidification, and Evaporative Cooling  

SciTech Connect

In this study, development of a novel system for combined water heating, dehumidification, and space evaporative cooling is discussed. Ambient water vapor is used as a working fluid in an open system. First, water vapor is absorbed from an air stream into an absorbent solution. The latent heat of absorption is transferred into the process water that cools the absorber. The solution is then regenerated in the desorber, where it is heated by a heating fluid. The water vapor generated in the desorber is condensed and its heat of phase change is transferred to the process water in the condenser. The condensed water can then be used in an evaporative cooling process to cool the dehumidified air exiting the absorber, or it can be drained if primarily dehumidification is desired. Essentially, this open absorption cycle collects space heat and transfers it to process water. This technology is enabled by a membrane-based absorption/desorption process in which the absorbent is constrained by hydrophobic vapor-permeable membranes. Constraining the absorbent film has enabled fabrication of the absorber and desorber in a plate-and-frame configuration. An air stream can flow against the membrane at high speed without entraining the absorbent, which is a challenge in conventional dehumidifiers. Furthermore, the absorption and desorption rates of an absorbent constrained by a membrane are greatly enhanced. Isfahani and Moghaddam (Int. J. Heat Mass Transfer, 2013) demonstrated absorption rates of up to 0.008 kg/m2s in a membrane-based absorber and Isfahani et al. (Int. J. Multiphase Flow, 2013) have reported a desorption rate of 0.01 kg/m2s in a membrane-based desorber. The membrane-based architecture also enables economical small-scale systems, novel cycle configurations, and high efficiencies. The absorber, solution heat exchanger, and desorber are fabricated on a single metal sheet. In addition to the open arrangement and membrane-based architecture, another novel feature of the cycle is recovery of the solution heat energy exiting the desorber by process water (a process-solution heat exchanger ) rather than the absorber exiting solution (the conventional solution heat exchanger ). This approach has enabled heating the process water from an inlet temperature of 15 C to 57 C (conforming to the DOE water heater test standard) and interfacing the process water with absorbent on the opposite side of a single metal sheet encompassing the absorber, process-solution heat exchanger, and desorber. The system under development has a 3.2 kW water heating capacity and a target thermal coefficient of performance (COP) of 1.6.

CHUGH, Devesh [University of Florida, Gainesville; Gluesenkamp, Kyle R [ORNL; Abdelaziz, Omar [ORNL; Moghaddam, Saeed [University of Florida, Gainesville

2014-01-01

57

The Role of Cross-Cultural Absorptive Capacity in the Effectiveness of In-Country Cross-Cultural Training  

ERIC Educational Resources Information Center

Based on the theory of absorptive capacity, this study examines the following question. In the context of cross-cultural training, can the amount of previously accumulated cultural knowledge affect the ability of a trainee to absorb further learning about a new culture, thus enhancing total knowledge and presumably cross-cultural adjustment?…

Tarique, Ibraiz; Caligiuri, Paula

2009-01-01

58

Experimental Investigations on the Characteristics of the Ammonia-Water Absorption Refrigerator for Low Temperature Solution Cycle  

NASA Astrophysics Data System (ADS)

This report refers to some static characteristics of the ammonia-water absorption refrigerator for low temperature refrigerating process which needs the temperature below the freezing point. Especially, the influence of evaporating temperature and cooling water temperature is clarified by the experimental investigation. In addition to this, the validity of constructed simulation model of this absorption refrigerator is mentioned. The validity of simulation model is verified by the comparison of experimental results and calculation. To examine the characteristics, we conducted the performance test using the trial product of which the standard cooling capacity is 175kW. The performance is estimated according to cooling capacity and COP. As a result, the effects of the evaporating temperature and cooling water temperature on the cooling performance are clarified by the experimental research. Furthermore, the calculation of the static characteristics predicted by the simulation model is in good agreements with the experimental results.

Takei, Toshitaka; Kimijima, Shinji; Saito, Kiyoshi; Kawai, Sunao

59

Investigation of the Emission and Absorption Spectra of Water Vapor  

NASA Astrophysics Data System (ADS)

Emission and absorption spectra of water vapor are measured and analyzed for temperatures 350-2500 K in the spectral range 0.57-25 ?m. Based on the developed mathematical model of radiative transfer, the parameters of spectral transmission functions of N2O vapors are obtained at different temperatures. Practical application of the obtained radiative characteristics is considered for solving problems of radiative heat exchange in high-temperature media and designing optoelectronic systems intended for monitoring of aero carriers.

Moskalenko, N. I.; Il'in, Yu. A.; Sadykov, M. S.

2015-01-01

60

A Water Vapor Differential Absorption LIDAR Design for Unpiloted Aerial Vehicles  

NASA Technical Reports Server (NTRS)

This system study proposes the deployment of a water vapor Differential Absorption LIDAR (DIAL) system on an Altair unmanned aerial vehicle (UAV) platform. The Altair offers improved payload weight and volume performance, and longer total flight time as compared to other commercial UAV's. This study has generated a preliminary design for an Altair based water vapor DIAL system. The design includes a proposed DIAL schematic, a review of mechanical challenges such as temperature and humidity stresses on UAV deployed DIAL systems, an assessment of the available capacity for additional instrumentation (based on the proposed design), and an overview of possible weight and volume improvements associated with the use of customized electronic and computer hardware, and through the integration of advanced fiber-optic and laser products. The results of the study show that less than 17% of the available weight, less than 19% of the volume capacity, and approximately 11% of the electrical capacity is utilized by the proposed water vapor DIAL system on the Altair UAV.

DeYoung, Russell J.; Mead, Patricia F.

2004-01-01

61

Public water supplies of North Carolina : a summary of water sources, use, treatment, and capacity of water-supply systems  

USGS Publications Warehouse

Data were collected during 1970-76 on 224 public water supply systems in North Carolina with 500 or more customers. This report summarizes these data that were previously published in five separate regional reports. The data are presented in order to Council of Government region, county, and water system name and include population served, average and maximum daily use, industrial use, water source, allowable draft of surface-water supplies, raw water pumping capacity, raw and finished water storage, type of water treatment, treatment plant capacity, and a summary of the chemical quality of finished water. Tables and maps provide cross references for system names, counties, Council of Government regions and water source.

Mann, L.T., Jr.

1978-01-01

62

Community Capacity for Adaptation to Climate-Induced Water Shortages: Linking Institutional Complexity and Local Actors  

Microsoft Academic Search

There is growing concern for the capacity of urban and rural communities to manage current water shortages and to prepare for shortages that may accompany predicted changes in climate. In this paper, concepts relating to the notion of climate adaptation and particularly “capacity building” are used to elucidate several determinants of community-level capacity for water management. These concepts and criteria

Janet L. Ivey; John Smithers; Rob C. de Loë; Reid D. Kreutzwiser

2004-01-01

63

Water vapor differential absorption lidar development and evaluation.  

PubMed

A ground-based differential absorption lidar (DIAL) system is described which has been developed for vertical range-resolved measurements of water vapor. The laser transmitter consists of a ruby-pumped dye laser, which is operated on a water vapor absorption line at 724.372 nm. Part of the ruby laser output is transmitted simultaneously with the dye laser output to determine atmospheric scattering and attenuation characteristics. The dye and ruby laser backscattered light is collected by a 0.5-m diam telescope, optically separated in the receiver package, and independently detected using photomultiplier tubes. Measurements of vertical water vapor concentration profiles using the DIAL system at night are discussed, and comparisons are made between the water vapor DIAL measurements and data obtained from locally launched rawinsondes. Agreement between these measurements was found to be within the uncertainty of the rawinsonde data to an altitude of 3 km. Theoretical simulations of this measurement were found to give reasonably accurate predictions of the random error of the DIAL measurements. Confidence in these calculations will permit the design of aircraft and Shuttle DIAL systems and experiments using simulation results as the basis for defining lidar system performance requirements. PMID:20216627

Browell, E V; Wilkerson, T D; McIlrath, T J

1979-10-15

64

Water Absorption in Internally Cured Mortar Made with Water-Filled Lightweight Aggregate  

E-print Network

Water Absorption in Internally Cured Mortar Made with Water- Filled Lightweight Aggregate 1 2 3 4 5 for shrinkage cracking in low w/c concrete has spawned the development of new technologies that can reduce the risk of early-age cracking. One of these is internal curing. Internal curing uses saturated lightweight

Bentz, Dale P.

65

Absorption capacity of major urban afforestation species in northeastern China to heavy metal pollutants in the atmosphere  

Microsoft Academic Search

Totally 24 arbor tree species and 6 shrub species were measured on their absorption capacities to heavy metal Pb, Cd, Cr,\\u000a and Hg by collecting and analyzing the leaves of trees along different streets in Harbin city in Sept. to Oct. of 2003. The\\u000a results showed that all the measured species had certain absorbency to the pollutants (Pb, Cd, Cr

Mu Li-qiang; Sun Hai-yan; Zhu Ning

2004-01-01

66

HI Absorption in the Gigamaser Galaxy TXS 2226-184 and the Relation between HI Absorption and Water Emission  

E-print Network

We report on the discovery of HI in absorption toward the gigamaser galaxy TXS2226-184 using the VLA. The absorption appears to consist of two components -- one with a width of 125 km/s, and one broader (420 km/s), both toward the compact radio source in the nucleus of the galaxy. Based on these large velocity widths we suggest that the HI absorption is produced in the central parsecs of the galaxy, on a similar scale to that which gives rise to the water maser emission. This brings to eight the number of galaxies known to exhibit both water masers and HI absorption. We explore the relationship between these two phenomena, and present a physically motivated (but unfruitful) search for water maser emission in five radio galaxies known to exhibit strong HI absorption.

G. B. Taylor; A. B. Peck; C. Henkel; H. Falcke; C. G. Mundell; C. P. O'Dea; S. A. Baum; J. F. Gallimore

2002-03-22

67

PURE WATER ABSORPTION COEFFICIENT AROUND 400NM: LAB MEASURED VERSUS FIELD OBSERVED  

E-print Network

PURE WATER ABSORPTION COEFFICIENT AROUND 400NM: LAB MEASURED VERSUS FIELD OBSERVED Zhongping Lee of the ratio of the backscattering coefficient to the absorption coefficient (or the sum of absorption]. In general, it has been found that reflectance can be well explained (or modeled) using known absorption

Lee, Zhongping

68

AN AMMONIA-WATER ABSORPTION-HIAT-PUMP CYCLE Donald Kuhlenschmidt, Member ASHRAE  

E-print Network

#12;AN AMMONIA-WATER ABSORPTION-HIAT-PUMP CYCLE BY Donald Kuhlenschmidt, Member ASHRAE Richard H. Merrick, Member ASHRAE ABSTRACT The scate-of-art in ammonia-water absorption cooling has been applied,000 Btuh) input unit reported. KLY WORDS Absorption Heat-pump Air conditioning heating Ammonia Donald

Oak Ridge National Laboratory

69

Water vapour and greenhouse trapping: The role of far infrared absorption  

Microsoft Academic Search

Few observations have been made of atmospheric absorption across the far infrared. Yet water vapour absorption in this spectral region may significantly effect climate. The impact of far infrared absorption is assessed by calculating the spectral variation of the total and water vapour greenhouse effects, for the sub-arctic winter (SAW) and tropical (TRP) standard atmospheres. Although the calculated efficiency of

Ashok Sinha; John E. Harries

1995-01-01

70

Microclimate in ski boots--temperature, relative humidity, and water absorption.  

PubMed

Ski boot quality is determined by mechanical properties and comfort. Comfort is strongly affected by cold feet. The purpose of this study was to determine the microclimate in ski boots. Climate chamber tests with five male subjects and field tests with two male subjects were conducted. Temperature and relative humidity were measured using four sensors placed on the foot and one on the liner. Absorbed water in liners and socks was measured with a precision balance. The subjects gave subjective ratings for comfort. The toe sensor temperature dropped below 20 °C at an ambient temperature of 0 °C, -10 °C, and -20 °C. Relative humidity values at the foot were as high as 78% in the climate chamber and 93% in the field. Water absorption in socks and liners ranged from 4 to 10 g in the climate chamber and 19 to 45.5 g in the field. The results reveal the importance of keeping the feet and in particular the toes warm during skiing. One possible improvement may be to construct the liner so that sweat and melted snow are kept as far away as possible from the foot. Liner material with high water absorption capacity and hydrophobic socks were suggested to prevent wet feet. PMID:23932378

Hofer, Patrick; Hasler, Michael; Fauland, Gulnara; Bechtold, Thomas; Nachbauer, Werner

2014-05-01

71

The correlation between molecular motions and heat capacity in normal ice and water  

E-print Network

The heat capacities of ice and water at ambient pressure are reexamined to build an intrinsic correlation between H2O molecular motions and the heat capacity. Based on the evolution of H2O molecular motions, a satisfactory description of the heat capacity of ice and water is provided. The heat capacity of ice is related not only to H2O molecular vibrations, but also to the molecular rotations. In water, all H2O molecular vibrations, rotations and translations contribute to the heat capacity. The molecular translational motions are found to be the main contribution to the large heat capacity of water. The results provide a deep insight into the nature of water and ice at ambient pressure.

Ke, Hai Bo; Wang, Wei Hua

2011-01-01

72

Temperature dependence of water vapor absorption coefficients for CO(2) differential absorption lidars.  

PubMed

A temperature correction of water vapor differential absorption coefficients for the CO(2) transition line pairs (10R20, 10R18) and (10R20, 10R22) for temperatures between -0.5 °C and 20 °C is computed, with a reference temperature of 27 °C, from medium-range CO(2) lidar field measurements. The empirical temperature correction, X(T), is fitted with the polynomial X(T) = ?(0) + ?(1) × T + ?(2) × T(2). For the transition line pair (10R20, 10R18) the temperature dependence ranges from 1.62%/°C to 3.47%/°C, and the temperature correction for the transition line pair (10R20, 10R22) ranges from 1.32%/°C to 2.43%/°C. PMID:20861968

Ben-David, A

1993-12-20

73

Water absorption in a refractive index model for bacterial spores  

NASA Astrophysics Data System (ADS)

The complexity of biological agents can make it difficult to identify the important factors impacting scattering characteristics among variables such as size, shape, internal structure and biochemical composition, particle aggregation, and sample additives. This difficulty is exacerbated by the environmentally interactive nature of biological organisms. In particular, bacterial spores equilibrate with environmental humidity by absorption/desorption of water which can affect both the complex refractive index and the size/shape distributions of particles - two factors upon which scattering characteristics depend critically. Therefore accurate analysis of experimental data for determination of refractive index must take account of particle water content. First, spectral transmission measurements to determine visible refractive index done on suspensions of bacterial spores must account for water (or other solvent) uptake. Second, realistic calculations of aerosol scattering cross sections should consider effects of atmospheric humidity on particle water content, size and shape. In this work we demonstrate a method for determining refractive index of bacterial spores bacillus atropheus (BG), bacillus thuringiensis (BT) and bacillus anthracis Sterne (BAs) which accounts for these effects. Visible index is found from transmission measurements on aqueous and DMSO suspensions of particles, using an anomalous diffraction approximation. A simplified version of the anomalous diffraction theory is used to eliminate the need for knowledge of particle size. Results using this approach indicate the technique can be useful in determining the visible refractive index of particles when size and shape distributions are not well known but fall within the region of validity of anomalous dispersion theory.

Siegrist, K. M.; Thrush, E.; Airola, M.; Carr, A. K.; Limsui, D. M.; Boggs, N. T.; Thomas, M. E.; Carter, C. C.

2009-05-01

74

GEOSTATISTICAL APPROACH FOR THE ASSESSMENT OF THE WATER RESERVOIR CAPACITY IN ARID REGIONS: A CASE STUDY  

E-print Network

geomorphologic process, human inference by dam construction accelerates the filling up of the reservoir capacity flows, its sediment carrying capacity is diminished due to the decrease in flow velocity and increase1 GEOSTATISTICAL APPROACH FOR THE ASSESSMENT OF THE WATER RESERVOIR CAPACITY IN ARID REGIONS

Paris-Sud XI, Université de

75

Enhancement of the grafting performance and of the water absorption of cassava starch graft copolymer by gamma radiation  

NASA Astrophysics Data System (ADS)

Enhancement of the gamma radiation grafting of acrylonitrile onto gelatinized cassava starch was investigated. Infrared spectrometry was used to follow the chemical changes in the grafting reaction and from saponification. The saponified starch- g-PAN (HSPAN) was then characterized in terms of grafting parameters to provide a guide for the optimum total dose (kGy) and the appropriate ratio of starch/acrylonitrile for a fixed dose rate of 2.5 × 10 -1 kGy/min. Other dose rates were also carried out to obtain the appropriate result of grafting copolymerization and of water absorption. A thin aluminium foil, covering the inner wall of the reaction vessel, was found to be far more effective than any other metal films in the enhancement of the grafting reaction and the water absorption as well. Nitric acid in the medium increases the grafting yield and the water absorption. Methyl ether hydroquinone inhibitor was evaluated for its ability to increase homopolymerization and decrease graft reaction. When styrene was used as a comonomer, it hampered the grafting of acrylonitrile onto starch backbone. The water absorption capacity was improved by freeze-drying the HSPAN. The treatment of the HSPAN with aluminium trichloride hexahydrate was found to enhance the degree of wicking, but to decrease the water absorbency.

Kiatkamjornwong, Suda; Meechai, Nispa

1997-06-01

76

In-situ Field Capacity and Soil Water Retention Measurements in Two Contrasting Soil Textures  

Technology Transfer Automated Retrieval System (TEKTRAN)

Knowledge of the in-situ field capacity and soil-water retention curve for soils is important for effective irrigation management and scheduling. The primary objective of this study was to estimate in-situ field capacity and soil water retention curves in the field using continually monitoring soil ...

77

Factors Affecting the Water Holding Capacity of Red Meat Products: A Review of Recent Research Advances  

Microsoft Academic Search

The water holding capacity of meat products is a very important quality attribute which has an influence on product yield, which in turn has economic implications, but is also important in terms of eating quality. A number of pre-and post-mortem factors influence the water holding capacity (WHC) of meat. During the growth and development of meat animals, genotype and animal

Qiaofen Cheng; Da-Wen Sun

2008-01-01

78

In-situ field capacity and soil water retention measurements in two contrasting soil textures  

Technology Transfer Automated Retrieval System (TEKTRAN)

Knowledge of the in-situ field capacity and soil-water retention curve for soils is important for effective irrigation management and scheduling. The primary objective of this study was to estimate in-situ field capacity and soil water retention curves in the field using continually monitoring soil ...

79

The impacts of different expansion modes on performance of small solar energy firms: perspectives of absorptive capacity.  

PubMed

The characteristics of firm's expansion by differentiated products and diversified products are quite different. However, the study employing absorptive capacity to examine the impacts of different modes of expansion on performance of small solar energy firms has never been discussed before. Then, a conceptual model to analyze the tension between strategies and corporate performance is proposed to filling the vacancy. After practical investigation, the results show that stronger organizational institutions help small solar energy firms expanded by differentiated products increase consistency between strategies and corporate performance; oppositely, stronger working attitudes with weak management controls help small solar energy firms expanded by diversified products reduce variance between strategies and corporate performance. PMID:24453837

Chen, Hsing Hung; Shen, Tao; Xu, Xin-Long; Ma, Chao

2013-01-01

80

The Impacts of Different Expansion Modes on Performance of Small Solar Energy Firms: Perspectives of Absorptive Capacity  

PubMed Central

The characteristics of firm's expansion by differentiated products and diversified products are quite different. However, the study employing absorptive capacity to examine the impacts of different modes of expansion on performance of small solar energy firms has never been discussed before. Then, a conceptual model to analyze the tension between strategies and corporate performance is proposed to filling the vacancy. After practical investigation, the results show that stronger organizational institutions help small solar energy firms expanded by differentiated products increase consistency between strategies and corporate performance; oppositely, stronger working attitudes with weak management controls help small solar energy firms expanded by diversified products reduce variance between strategies and corporate performance. PMID:24453837

Chen, Hsing Hung; Shen, Tao; Xu, Xin-long; Ma, Chao

2013-01-01

81

Water in coal pores: low-temperature heat capacity behavior of the moisture in wyodak coal.  

PubMed

The low-temperature heat capacity behavior of naturally occuring water in Wyodak coal indicates that there are two types of water present. More than two-thirds is "nonfreezable," displaying no evidence of a phase transition in the neighborhood of 273 K where normal bulk water melts. The remainder is "freezable," displaying a somewhat distorted heat capacity peak, which is indicative of a phase transition. This evidence suggests that the nonfreezable water is either adsorbed on the internal surfaces of the coal or is in smaller pores, whereas the freezable water is in larger pores. Parallels to the heat capacity behavior of the coal-water system include the water in a porous ceramic, water in the mineral endellite, and water in the protein collagen. PMID:17813082

Mraw, S C; Naas-O'rourke, D F

1979-08-31

82

A novel approach to national technological accumulation and absorptive capacity: aggregating Cohen and Levinthal  

Microsoft Academic Search

The paper develops a more precise specification and understanding of the process of national-level knowledge accumulation and absorptive capabilities by applying the reasoning and evidence from the firm-level analysis pioneered by Cohen and Levinthal (1989, 1990). In doing so, we acknowledge that significant cross-border effects due to the role of both inward and outward FDI exist and that assimilation of

Paola Criscuolo; Rajneesh Narula

2008-01-01

83

Fuzzy comprehensive evaluation model for water resources carrying capacity in Tarim River Basin, Xinjiang, China  

Microsoft Academic Search

This paper explores the method of comprehensive evaluation of water resources carrying capacity and sets up an evaluation\\u000a model applying the fuzzy comprehensive evaluation method. Based on the data of nature, society, economics and water resources\\u000a of the Tarim River Basin in 2002, we evaluated the water resources carrying capacity of the basin by means of the model. The\\u000a results

Lihong Meng; Yaning Chen; Weihong Li; Ruifeng Zhao

2009-01-01

84

EVALUATING CAPACITIES OF GAC PRELOADED WITH NATURAL WATER  

EPA Science Inventory

Adsorption studies are conducted to determine how preloading a natural groundwater onto GAC affects the adsorption of cis-1,2-dichloroexthene in small-scale and pilot-scale columns. Capacities are determined from batch-isotherm tests, microcolumns, and pilot columns, which are p...

85

EVALUATING CAPACITIES OF GAC PRELOADED WITH A NATURAL WATER  

EPA Science Inventory

The effect of preloading a natural groundwater on the adsorption characteristics of cis-1,2-dichloroethene is evaluated. mphasis is placed on the quantification of the reductions in capacity and external mass transfer rates. reviously developed scale-up procedure is also evaluate...

86

THE EFFECT OF TEMPERATURE ON THE ABSORPTION OF WATER BY SODA-BOILED COTTON  

Microsoft Academic Search

Little work has hitherto been published on the effect of temperature on the absorption of water by cotton, and no data were available for temperatures higher than 38°C. The present experiments deal with the absorption of water by cotton, at all humidities and at temperatures up to 110°C., the data being therefore of practical application not only to the testing

Alexander Robert Urquhart; Alexander Mitchell Williams

1924-01-01

87

Direct Measurement of Water Cluster Concentrations by Infrared Cavity Ringdown Laser Absorption Spectroscopy  

E-print Network

method for measuring infrared spectra, infrared cavity ringdown laser absorption spectroscopy (IR in the terahertz (far- infrared) region of the spectrum,6 water clusters have been studied primarily in the midDirect Measurement of Water Cluster Concentrations by Infrared Cavity Ringdown Laser Absorption

Cohen, Ronald C.

88

Determination of the water vapor continuum absorption by THz-TDS and Molecular  

E-print Network

Determination of the water vapor continuum absorption by THz-TDS and Molecular Response Theory: Determination of the water vapor continuum absorption from 0.35 to 1 THz is reported. The THz pulses propagate though a 137 m long humidity-controlled chamber and are measured by THz time-domain spectroscopy (THz

Oklahoma State University

89

GEOGRAPHIC PATTERNS OF SOIL WATER-HOLDING CAPACITY IN THE CONTIGUOUS UNITED STATES  

EPA Science Inventory

The geographic patterns of soil water-holding capacity are important for studying the response of vegetation and water supply to climate change. his study was conducted to evaluate which dataset to use for national-scale water balance modeling. patial databases of soil properties...

90

Acid neutralizing capacity, alkalinity, and acid-base status of natural waters containing organic acids  

Microsoft Academic Search

The terms acid neutralizing capacity (ANC) and alkalinity (Alk) are extensively employed in the characterization of natural waters, including soft circumneutral or acidic waters. However, in the presence of organic acids, ANC measurements are inconsistent with many conceptual definitions of ANC or Alk and do not provide an adequate characterization of the acid-base chemistry of water. Knowledge of Gran ANC

Harold F. Hemond

1990-01-01

91

Investigation of Heat capacity and Specific Heat: Using Different Temperatures of Water and Solids  

NSDL National Science Digital Library

This activity is a chemistry lab-based investigation where students apply observational skills and critical thinking skills to finding specific heat and heat capacity using different temperatures of water and solids. A final activity will assess students understanding of specific heat and heat capacity and promote data analysis skills, using real-life situations.

92

Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt  

E-print Network

Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt 2014; published online 14 October 2014) Polyacrylamide hydrogels containing salt as electrolyte have of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced

Suo, Zhigang

93

The influence of water mixtures on the dermal absorption of glycol ethers  

SciTech Connect

Glycol ethers are solvents widely used alone and as mixtures in industrial and household products. Some glycol ethers have been shown to have a range of toxic effects in humans following absorption and metabolism to their aldehyde and acid metabolites. This study assessed the influence of water mixtures on the dermal absorption of butoxyethanol and ethoxyethanol in vitro through human skin. Butoxyethanol penetrated human skin up to sixfold more rapidly from aqueous solution (50%, 450 mg/ml) than from the neat solvent. Similarly penetration of ethoxyethanol was increased threefold in the presence of water (50%, 697 mg/ml). There was a corresponding increase in apparent permeability coefficient as the glycol ether concentration in water decreased. The maximum penetration rate of water also increased in the presence of both glycol ethers. Absorption through a synthetic membrane obeyed Fick's Law and absorption through rat skin showed a similar profile to human skin but with a lesser effect. The mechanisms for this phenomenon involves disruption of the stratum corneum lipid bilayer by desiccation by neat glycol ether micelles, hydration with water mixtures and the physicochemical properties of the glycol ether-water mixtures. Full elucidation of the profile of absorption of glycol ethers from mixtures is required for risk assessment of dermal exposure. This work supports the view that risk assessments for dermal contact scenarios should ideally be based on absorption data obtained for the relevant formulation or mixture and exposure scenario and that absorption derived from permeability coefficients may be inappropriate for water-miscible solvents.

Traynor, Matthew J. [Toxicology Unit, Institute for Research on Environment and Sustainability and Medical School, University of Newcastle upon Tyne, Newcastle NE1 7RU (United Kingdom); Wilkinson, Simon C. [Toxicology Unit, Institute for Research on Environment and Sustainability and Medical School, University of Newcastle upon Tyne, Newcastle NE1 7RU (United Kingdom); Williams, Faith M. [Toxicology Unit, Institute for Research on Environment and Sustainability and Medical School, University of Newcastle upon Tyne, Newcastle NE1 7RU (United Kingdom)]. E-mail: F.M.Williams@ncl.ac.uk

2007-01-15

94

Water for Texas: Applicant Capacity Assessment Tool for the Economically Distressed Areas Program  

E-print Network

Williams Whitney Scott Megan Stubbs Dr. Deborah Kerr, Advisor Project Mission Statement To develop an evaluation tool to assist the Texas Water Development Board in assessing the capacity of applicants to complete proposed water projects in economically... distressed areas This project was a partnership between the George Bush School of Government and Public Service at Texas A&M University and the Texas Water Development Board II Executive Summary Since 1989, the Texas Water Development Board (TWDB...

Bennett, Jason; Dascaliuc, Svetlana; Grossman, Nick; Hunt, Michael; Kenesson, Laura; Madden, Tara; McWilliams, Austin; Scott, Whitney; Stubbs, Megan

2005-01-01

95

Optical absorption of pure water in the blue and ultraviolet  

E-print Network

The key feature of the Integrating Cavity Absorption Meter (ICAM) is that it produces an isotropic illumination of the liquid sample and thereby dramatically minimizes scattering effects. The ICAM can produce an effective optical path...

Lu, Zheng

2007-09-17

96

Modeling Climate-Water Impacts on Electricity Sector Capacity Expansion: Preprint  

SciTech Connect

Climate change has the potential to exacerbate water availability concerns for thermal power plant cooling, which is responsible for 41% of U.S. water withdrawals. This analysis describes an initial link between climate, water, and electricity systems using the National Renewable Energy Laboratory (NREL) Regional Energy Deployment System (ReEDS) electricity system capacity expansion model. Average surface water projections from Coupled Model Intercomparison Project 3 (CMIP3) data are applied to surface water rights available to new generating capacity in ReEDS, and electric sector growth is compared with and without climate-influenced water rights. The mean climate projection has only a small impact on national or regional capacity growth and water use because most regions have sufficient unappropriated or previously retired water rights to offset climate impacts. Climate impacts are notable in southwestern states that purchase fewer water rights and obtain a greater share from wastewater and other higher-cost water resources. The electric sector climate impacts demonstrated herein establish a methodology to be later exercised with more extreme climate scenarios and a more rigorous representation of legal and physical water availability.

Cohen, S. M.; Macknick, J.; Averyt, K.; Meldrum, J.

2014-05-01

97

INFLUENCE OF AQUEOUS ALUMINUM AND ORGANIC ACIDS ON MEASUREMENT OF ACID NEUTRALIZING CAPACITY IN SURFACE WATERS  

EPA Science Inventory

Acid neutralizing capacity (ANC) is used to quantify the acid-base status of surface waters. Acidic waters have bean defined as having ANC values less than zero, and acidification is often quantified by decreases in ANC. Measured and calculated values of ANC generally agree, exce...

98

Variations in the mass-specific absorption coefficient of mineral particles suspended in water  

Microsoft Academic Search

We examined the light-absorption properties of various samples of mineral particles suspended in water, which included pure mineral species (quartz, calcite, illite, kaolinite, and montmorillonite) and natural particulate assem- blages such as desert dust originating from different locations in the Sahara. The absorption coefficient was measured in the spectral region from ultraviolet (UV) to near-infrared on particle suspensions, using a

Marcel Babin; Dariusz Stramski

2004-01-01

99

Absorption spectrum (380–700 nm) of pure water. II. Integrating cavity measurements  

Microsoft Academic Search

Definitive data on the absorption spectrum of pure water from 380 to 700 nm have been obtained with an integrating cavity technique. The results are in good agreement with those recently obtained by our group with a completely independent photothermal technique. As before, we find that the absorption in the blue is significantly lower than had previously been generally believed

Robin M. Pope; Edward S. Fry

1997-01-01

100

Oil sorbents with high sorption capacity, oil/water selectivity and reusability for oil spill cleanup.  

PubMed

A sorbent for oil spill cleanup was prepared through a novel strategy by treating polyurethane sponges with silica sol and gasoline successively. The oil sorption capacity, oil/water selectivity, reusability and sorption mechanism of prepared sorbent were studied. The results showed that the prepared sorbent exhibited high sorption capacity and excellent oil/water selectivity. 1g of the prepared sorbent could adsorb more than 100 g of motor oil, while it only picks up less than 0.1 g of water from an oil-water interface under both static and dynamic conditions. More than 70% of the sorption capacity remained after 15 successive sorption-squeezing cycles, which suggests an extraordinary high reusability. The prepared sorbent is a better alternative of the commercial polypropylene sorbent which are being used nowadays. PMID:24856092

Wu, Daxiong; Fang, Linlin; Qin, Yanmin; Wu, Wenjuan; Mao, Changming; Zhu, Haitao

2014-07-15

101

Absorption  

NSDL National Science Digital Library

This activity can be used to allow students to explore the concept of absorption using a variety of materials. Extensions include exploring how Native Americans used absorbtion in a number of ways. This inquiry activity was developed by a K-12 science teacher in the American Physiological SocietyÃÂs 1998 Frontiers in Physiology Program. The NSES Standards addressed by this activity are current as of the year of development. For more information on the Frontiers in Physiology Program, please visit www.frontiersinphys.org.

Katherine M Knudson (Polson Middle School)

1998-04-01

102

Water vapor microwave continuum absorption: A comparison of measurements and models  

Microsoft Academic Search

Measurements, made in different laboratories, of absorption by water vapor in microwave windows are compared with models for the water vapor continuum. A reanalysis of some of these measurements leads to the conclusion that the laboratory data are best represented by a combination of Liebe's (1987) millimeter-wave propagation model (MPM) for the foreign-broadened component of the water continuum and the

Philip W. Rosenkranz

1998-01-01

103

Optoacoustic measurements of water vapor absorption at selected CO laser wavelengths in the 5-micron region  

NASA Technical Reports Server (NTRS)

Measurements of water vapor absorption were taken with a resonant optoacoustical detector (cylindrical pyrex detector, two BaF2 windows fitted into end plates at slight tilt to suppress Fabry-Perot resonances), for lack of confidence in existing spectral tabular data for the 5-7 micron region, as line shapes in the wing regions of water vapor lines are difficult to characterize. The measurements are required for air pollution studies using a CO laser, to find the differential absorption at the wavelengths in question due to atmospheric constituents other than water vapor. The design and performance of the optoacoustical detector are presented. Effects of absorption by ambient NO are considered, and the fixed-frequency discretely tunable CO laser is found suitable for monitoring urban NO concentrations in a fairly dry climate, using the water vapor absorption data obtained in the study.

Menzies, R. T.; Shumate, M. S.

1976-01-01

104

Beyond R&D activities: the determinants of firms’ absorptive capacity explaining the access to scientific institutes in low–medium-tech contexts  

Microsoft Academic Search

A firm's search strategy is to use innovation inputs from external sources such as suppliers, clients, competitors, universities and research transfer offices (RTOs) to complement their in-house knowledge. Thus, a firm needs to be capable of identifying and valuing the potential value of certain external knowledge, i.e. absorptive capacity. Most of the studies regarding search patterns are reduced mostly to

Jose-Luis Hervas-Oliver; José Albors-Garrigos; Juan-Jose Baixauli

2011-01-01

105

Beyond R&D activities: the determinants of firms’ absorptive capacity explaining the access to scientific institutes in low–medium-tech contexts  

Microsoft Academic Search

A firm's search strategy is to use innovation inputs from external sources such as suppliers, clients, competitors, universities and research transfer offices (RTOs) to complement their in-house knowledge. Thus, a firm needs to be capable of identifying and valuing the potential value of certain external knowledge, i.e. absorptive capacity. Most of the studies regarding search patterns are reduced mostly to

Jose-Luis Hervas-Oliver; José Albors-Garrigos; Juan-Jose Baixauli

2012-01-01

106

Derivation of water vapour absorption cross-sections in the red region  

NASA Technical Reports Server (NTRS)

Absorption spectrum in 436 to 448 nm wavelength region gives NO2 and O3 column densities. This spectrum can also give H2O column density. The spectrum in the range of 655 to 667 nm contains absorption due to NO3 and H2O. Combining the absorption spectra in the wavelength ranges of 436 to 448 and 655 to 667 nm, water vapor absorption cross-sections in this range comes out to be of the order of 2.0 x 10(exp -24) cm(exp -2).

Lal, M.; Chakrabarty, D. K.

1994-01-01

107

IR Absorption Coefficients for the Quantification of Water in Majoritic Garnet  

NASA Astrophysics Data System (ADS)

Majoritic garnet, Mg3(Fe,Al,Si)2(SiO4)3, plays an important role in the Earth's transition zone. So far, no independently determined IR absorption coefficient was reported for majoritic garnet, but the knowledge of its absolute water content is essential for modeling the Earth's deep water cycle. Mineral specific absorption coefficients for the quantification of water with IR spectroscopy are required since it has been shown that general linear IR calibrations do not hold for a variety of minerals in which water is not stoichiometrically incorporated but as hydroxyl point defects. In the present work we analyze a series of synthetic majorite single-crystals to provide absorption coefficients for IR spectroscopy. Majorite single-crystals with varying Fe-, Mg-, Al, Cr- and OH contents were synthesized at 18 GPa and 1800 K in a multi-anvil press. Single-crystals (50-500 ?m in size) were characterized using X-ray diffraction, microprobe analysis, IR and Moessbauer spectroscopy. Mineral specific absorption coefficients were calculated from independently determined water contents from secondary ion mass spectrometry. Unpolarized IR spectra of majorite show broad absorption features in the OH region with band maxima at ~3200, 3400, 3575 and 3625 cm-1. The absorption maxima of the OH bands are shifted depending on the composition of the samples. Here we present a mineral specific IR calibration for the quantification of water in majorite and discuss its dependency on compositional changes.

Thomas, S.; Wilson, K.; Koch-Mueller, M.; Jacobsen, S. D.; Hauri, E. H.

2013-12-01

108

A WATER VAPOR MONITOR USING DIFFERENTIAL INFRARED ABSORPTION  

EPA Science Inventory

A water vapor monitor has been developed with adequate sensitivity and versatility for a variety of applications. Two applications for which the instrument has been designed are the continuous monitoring of water in ambient air and the measuring of the mass of water desorbed from...

109

Water and solute absorption from hypotonic glucose-electrolyte solutions in human jejunum.  

PubMed Central

While oral rehydration therapy with glucose-electrolyte solutions is highly effective, the optimal formulation has not yet been defined. Recent clinical studies suggest that stool volume, and thus water losses, may be reduced if glucose is replaced by a polymeric substrate which reduces osmolality. It is possible that the efficacy of glucose monomer based oral rehydration solutions (ORS) will also improve if osmolality is decreased. Using jejunal triple lumen perfusion in healthy adult volunteers net water and solute absorption were studied from three hypotonic solutions with different sodium concentrations (46, 60, 75 mmol/l) but identical glucose concentrations (90 mmol/l), thus allowing osmolality to rise (210, 240, and 270 mOsm/kg, respectively). Results from these solutions (ORS 45:210, ORS 60:240, and ORS 75:270) were compared with the World Health Organisation oral rehydration solution (WHO-ORS). Greatest water absorption was seen with ORS 60:240 (p less than 0.01). Sodium absorption from ORS 60:240 and WHO-ORS was similar and greater than sodium absorption from ORS 45:210 (p less than 0.05). Potassium and glucose absorption were greater from ORS 60:240 than from any of the other hypotonic solutions (p less than 0.05) and were equal to absorption from WHO-ORS). These results in a short segment of healthy human jejunum suggest that hypotonic ORS containing monomeric glucose may increase water absorption. PMID:1582591

Hunt, J B; Elliott, E J; Fairclough, P D; Clark, M L; Farthing, M J

1992-01-01

110

Modeling water resources as a constraint in electricity capacity expansion models  

NASA Astrophysics Data System (ADS)

In the United States, the electric power sector is the largest withdrawer of freshwater in the nation. The primary demand for water from the electricity sector is for thermoelectric power plant cooling. Areas likely to see the largest near-term growth in population and energy usage, the Southwest and the Southeast, are also facing freshwater scarcity and have experienced water-related power reliability issues in the past decade. Lack of water may become a barrier for new conventionally-cooled power plants, and alternative cooling systems will impact technology cost and performance. Although water is integral to electricity generation, it has long been neglected as a constraint in future electricity system projections. Assessing the impact of water resource scarcity on energy infrastructure development is critical, both for conventional and renewable energy technologies. Efficiently utilizing all water types, including wastewater and brackish sources, or utilizing dry-cooling technologies, will be essential for transitioning to a low-carbon electricity system. This work provides the first demonstration of a national electric system capacity expansion model that incorporates water resources as a constraint on the current and future U.S. electricity system. The Regional Electricity Deployment System (ReEDS) model was enhanced to represent multiple cooling technology types and limited water resource availability in its optimization of electricity sector capacity expansion to 2050. The ReEDS model has high geographic and temporal resolution, making it a suitable model for incorporating water resources, which are inherently seasonal and watershed-specific. Cooling system technologies were assigned varying costs (capital, operations and maintenance), and performance parameters, reflecting inherent tradeoffs in water impacts and operating characteristics. Water rights supply curves were developed for each of the power balancing regions in ReEDS. Supply curves include costs and availability of freshwater (surface and groundwater) and alternative water resources (municipal wastewater and brackish groundwater). In each region, a new power plant must secure sufficient water rights for operation before being built. Water rights constraints thus influence the type of power plant, cooling system, or location of new generating capacity. Results indicate that the aggregate national generating capacity by fuel type and associated carbon dioxide emissions change marginally with the inclusion of water rights. Water resource withdrawals and consumption, however, can vary considerably. Regional water resource dynamics indicate substantial differences in the location where power plant-cooling system technology combinations are built. These localized impacts highlight the importance of considering water resources as a constraint in the electricity sector when evaluating costs, transmission infrastructure needs, and externalities. Further scenario evaluations include assessments of how climate change could affect the availability of water resources, and thus the development of the electricity sector.

Newmark, R. L.; Macknick, J.; Cohen, S.; Tidwell, V. C.; Woldeyesus, T.; Martinez, A.

2013-12-01

111

Influence of meal composition on canine jejunal water and electrolyte absorption.  

PubMed

The absorption of water and electrolytes from the proximal jejunal lumen increases immediately after a meal. This meal-induced jejunal absorption occurs in jejunal segments out of normal gastrointestinal continuity. This study was designed to characterize the jejunal absorptive response to a series of isovolumetric gavage-delivered stimuli. Twenty-five-centimeter canine proximal jejunal Thiry-Vella fistulas were constructed, and jejunal absorption studies (n = 66) were performed by luminal perfusion of the jejunal segments with an isotonic buffer containing 14C-labeled polyethylene glycol. Each study consisted of a 1-hour basal period, followed by a 3-hour experimental period. Nine groups were studied, each receiving one of the following isovolumetric stimuli delivered via the gavage route: water, 0.9% saline, mixed meal, protein, lipid, carbohydrate, and mannitol (150 mmol/L, 300 mmol/L, and 600 mmol/L). The water and 0.9% saline gavage groups showed no significant changes in integrated postprandial water and electrolyte absorption above basal. The isocaloric mixed meal, protein, lipid, carbohydrate, and mannitol groups all had significantly increased integrated postprandial jejunal water and electrolyte absorption above basal (P less than 0.05). These results indicate that a proabsorptive signal for meal-induced jejunal absorption originates from or distal to the stomach. Meal-induced jejunal absorption occurs in response to nutrients of diverse composition and is also responsive to nonnutritive solutes such as mannitol. These findings support a new role for gastric or intestinal chemo- or osmo-receptors in stimulating the neurohumoral mechanisms that mediate meal-induced jejunal absorption. PMID:1732119

Bastidas, J A; Zinner, M J; Bastidas, J A; Orandle, M S; Yeo, C J

1992-02-01

112

Solvation thermodynamics and heat capacity of polar and charged solutes in water  

SciTech Connect

The solvation thermodynamics and in particular the solvation heat capacity of polar and charged solutes in water is studied using atomistic molecular dynamics simulations. As ionic solutes we consider a F{sup -} and a Na{sup +} ion, as an example for a polar molecule with vanishing net charge we take a SPC/E water molecule. The partial charges of all three solutes are varied in a wide range by a scaling factor. Using a recently introduced method for the accurate determination of the solvation free energy of polar solutes, we determine the free energy, entropy, enthalpy, and heat capacity of the three different solutes as a function of temperature and partial solute charge. We find that the sum of the solvation heat capacities of the Na{sup +} and F{sup -} ions is negative, in agreement with experimental observations, but our results uncover a pronounced difference in the heat capacity between positively and negatively charged groups. While the solvation heat capacity {Delta}C{sub p} stays positive and even increases slightly upon charging the Na{sup +} ion, it decreases upon charging the F{sup -} ion and becomes negative beyond an ion charge of q=-0.3e. On the other hand, the heat capacity of the overall charge-neutral polar solute derived from a SPC/E water molecule is positive for all charge scaling factors considered by us. This means that the heat capacity of a wide class of polar solutes with vanishing net charge is positive. The common ascription of negative heat capacities to polar chemical groups might arise from the neglect of non-additive interaction effects between polar and apolar groups. The reason behind this non-additivity is suggested to be related to the second solvation shell that significantly affects the solvation thermodynamics and due to its large spatial extent induces quite long-ranged interactions between solvated molecular parts and groups.

Sedlmeier, Felix; Netz, Roland R. [Fachbereich Physik, Freie Universitaet Berlin, 14195 Berlin (Germany)

2013-03-21

113

Liquid water absorption and scattering effects in DOAS retrievals over oceans  

NASA Astrophysics Data System (ADS)

Spectral effects of liquid water are present in absorption (differential optical absorption spectroscopy - DOAS) measurements above the ocean and, if insufficiently removed, may interfere with trace gas absorptions, leading to wrong results. Currently available literature cross sections of liquid water absorption are provided in coarser resolution than DOAS applications require, and vibrational Raman scattering (VRS) is mostly not considered, or is compensated for using simulated pseudo cross sections from radiative transfer modeling. During the ship-based TransBrom campaign across the western Pacific in October 2009, MAX-DOAS (Multi-AXis differential optical absorption spectroscopy) measurements of light penetrating very clear natural waters were performed, achieving average underwater light paths of up to 50 m. From these measurements, the retrieval of a correction spectrum (H2Ocorr) is presented, compensating simultaneously for insufficiencies in the liquid water absorption cross section and broad-banded VRS structures. Small-banded structures caused by VRS were found to be very efficiently compensated for by the intensity offset correction included in the DOAS fit. No interference between the H2Ocorr spectrum and phytoplankton absorption was found. In the MAX-DOAS tropospheric NO2 retrieval, this method was able to compensate entirely for all liquid water effects that decrease the fit quality, and performed better than using a liquid water cross section in combination with a simulated VRS spectrum. The decrease in the residual root mean square (rms) of the DOAS fit depends on the measurement's contamination with liquid water structures, and ranges from ? 30% for measurements slightly towards the water surface to several percent in small angles above the horizon. Furthermore, the H2Ocorr spectrum was found to prevent misfits of NO2 slant columns, especially for very low NO2 scenarios, and thus increases the reliability of the fit. In test fits on OMI satellite data, the H2Ocorr spectrum was found selectively above ocean surfaces, where it decreases the rms by up to ? 11 %.

Peters, E.; Wittrock, F.; Richter, A.; Alvarado, L. M. A.; Rozanov, V. V.; Burrows, J. P.

2014-12-01

114

[The evaluation of the nutritional condition and the absorptive capacity in long-term follow-up of infants with short bowel syndrome].  

PubMed

The nutritional conditions and absorptive capacity of nine infants with short bowel syndrome were investigated during a long follow-up period from one and half years to 14 years and 7 months. The length of the residual small intestine ranged between 13 and 90cm. The nine infants had normal meals at home and did not suffer from persistent diarrhea. Most of the infants were thin. Nutritional conditions, for example, serum protein, triglycerides, vitamins, trace elements and plasma amino acids, were kept relatively well, and there were no symptoms of deficiency. The results of D-xylose absorption test had gradually improved but the absorptive capacity of sugars and amino acids observed by potential differences were within the normal limits or slightly subnormal except one infant. This indicated that the absorptive capacity of sugars and amino acids per a given area of the residual small intestine did not increase. From our examination the critical length of intestine might be in the neighborhood of 50cm. The infants left with less than 50cm of small intestine seem to have grown up normally but malabsorption of fat, sugars and bile acids have continued for many years. PMID:4033627

Ohkohchi, N; Igarashi, Y; Abe, H; Ohi, R; Kasai, M

1985-06-01

115

Wetting and absorption of water drops on Nafion films.  

PubMed

Water drops on Nafion films caused the surface to switch from being hydrophobic to being hydrophilic. Contact angle hysteresis of >70 degrees between advancing and receding values were obtained by the Wilhelmy plate technique. Sessile drop measurements were consistent with the advancing contact angle; the sessile drop contact angle was 108 degrees . Water drop adhesion, as measured by the detachment angle on an inclined plane, showed much stronger water adhesion on Nafion than Teflon. Sessile water and methanol drops caused dry Nafion films to deflect. The flexure went through a maximum with time. Flexure increased with contact area of the drop, but was insensitive to the film thickness. Methanol drops spread more on Nafion and caused larger film flexure than water. The results suggest that the Nafion surface was initially hydrophobic but water and methanol drops caused hydrophilic sulfonic acid domains to be drawn to the Nafion surface. Local swelling of the film beneath the water drop caused the film to buckle. The maximum flexure is suggested to result from motion of a water swelling front through the Nafion film. PMID:18611043

Goswami, Sharonmoyee; Klaus, Shannon; Benziger, Jay

2008-08-19

116

Water vapor profiling using a widely tunable amplified diode laser Differential Absorption Lidar (DIAL)  

Microsoft Academic Search

Water vapor is one of the most significant constituents of the atmosphere because of its role in cloud formation, precipitation, and interactions with electromagnetic radiation, especially its absorption of longwave infrared radiation. Some details of the role of water vapor and related feedback mechanisms in the Earth system need to be characterized better if local weather, global climate, and the

Michael Drew Obland

2007-01-01

117

Dynamics of Water Absorption and Evaporation During Methanol Droplet Combustion in Microgravity  

NASA Technical Reports Server (NTRS)

The combustion of methanol droplets is profoundly influenced by the absorption and evaporation of water, generated in the gas phase as a part of the combustion products. Initially there is a water-absorption period of combustion during which the latent heat of condensation of water vapor, released into the droplet, enhances its burning rate, whereas later there is a water-evaporation period, during which the water vapor reduces the flame temperature suffciently to extinguish the flame. Recent methanol droplet-combustion experiments in ambient environments diluted with carbon dioxide, conducted in the Combustion Integrated Rack on the International Space Station (ISS), as a part of the FLEX project, provided a method to delineate the water-absorption period from the water-evaporation period using video images of flame intensity. These were obtained using an ultra-violet camera that captures the OH* radical emission at 310 nm wavelength and a color camera that captures visible flame emission. These results are compared with results of ground-based tests in the Zero Gravity Facility at the NASA Glenn Research Center which employed smaller droplets in argon-diluted environments. A simplified theoretical model developed earlier correlates the transition time at which water absorption ends and evaporation starts. The model results are shown to agree reasonably well with experiment.

Hicks, Michael C.; Dietrich, Daniel L.; Nayagam, Vedha; Williams, Forman A.

2012-01-01

118

Air-cooled LiBr–water absorption chillers for solar air conditioning in extremely hot weathers  

Microsoft Academic Search

A low temperature-driven absorption cycle is theoretically investigated for the development of an air-cooled LiBr–water absorption chiller to be combined with low-cost flat solar collectors for solar air conditioning in hot and dry regions. The cycle works with dilute LiBr–water solutions so that risk of LiBr crystallization is less than for commercially available water-cooled LiBr–water absorption chillers even in extremely

D. S. Kim; C. A. Infante Ferreira

2009-01-01

119

Methods for analysis of selected metals in water by atomic absorption  

USGS Publications Warehouse

This manual describes atomic-absorption-spectroscopy methods for determining calcium, copper, lithium, magnesium, manganese, potassium, sodium, strontium and zinc in atmospheric precipitation, fresh waters, and brines. The procedures are intended to be used by water quality laboratories of the Water Resources Division of the U.S. Geological Survey. Detailed procedures, calculations, and methods for the preparation of reagents are given for each element along with data on accuracy, precision, and sensitivity. Other topics discussed briefly are the principle of atomic absorption, instrumentation used, and special analytical techniques.

Fishman, Marvin J.; Downs, Sanford C.

1966-01-01

120

Simulation of Water Environmental Capacity and Pollution Load Reduction Using QUAL2K for Water Environmental Management  

PubMed Central

In recent years, water quality degradation associated with rapid socio-economic development in the Taihu Lake Basin, China, has attracted increasing attention from both the public and the Chinese government. The primary sources of pollution in Taihu Lake are its inflow rivers and their tributaries. Effective water environmental management strategies need to be implemented in these rivers to improve the water quality of Taihu Lake, and to ensure sustainable development in the region. The aim of this study was to provide a basis for water environmental management decision-making. In this study, the QUAL2K model for river and stream water quality was applied to predict the water quality and environmental capacity of the Hongqi River, which is a polluted tributary in the Taihu Lake Basin. The model parameters were calibrated by trial and error until the simulated results agreed well with the observed data. The calibrated QUAL2K model was used to calculate the water environmental capacity of the Hongqi River, and the water environmental capacities of CODCr NH3-N, TN, and TP were 17.51 t, 1.52 t, 2.74 t and 0.37 t, respectively. The results showed that the NH3-N, TN, and TP pollution loads of the studied river need to be reduced by 50.96%, 44.11%, and 22.92%, respectively to satisfy the water quality objectives. Thus, additional water pollution control measures are needed to control and reduce the pollution loads in the Hongqi River watershed. The method applied in this study should provide a basis for water environmental management decision-making. PMID:23222206

Zhang, Ruibin; Qian, Xin; Yuan, Xingcheng; Ye, Rui; Xia, Bisheng; Wang, Yulei

2012-01-01

121

Simulation of water environmental capacity and pollution load reduction using QUAL2K for water environmental management.  

PubMed

In recent years, water quality degradation associated with rapid socio-economic development in the Taihu Lake Basin, China, has attracted increasing attention from both the public and the Chinese government. The primary sources of pollution in Taihu Lake are its inflow rivers and their tributaries. Effective water environmental management strategies need to be implemented in these rivers to improve the water quality of Taihu Lake, and to ensure sustainable development in the region. The aim of this study was to provide a basis for water environmental management decision-making. In this study, the QUAL2K model for river and stream water quality was applied to predict the water quality and environmental capacity of the Hongqi River, which is a polluted tributary in the Taihu Lake Basin. The model parameters were calibrated by trial and error until the simulated results agreed well with the observed data. The calibrated QUAL2K model was used to calculate the water environmental capacity of the Hongqi River, and the water environmental capacities of COD(Cr) NH(3)-N, TN, and TP were 17.51 t, 1.52 t, 2.74 t and 0.37 t, respectively. The results showed that the NH(3)-N, TN, and TP pollution loads of the studied river need to be reduced by 50.96%, 44.11%, and 22.92%, respectively to satisfy the water quality objectives. Thus, additional water pollution control measures are needed to control and reduce the pollution loads in the Hongqi River watershed. The method applied in this study should provide a basis for water environmental management decision-making. PMID:23222206

Zhang, Ruibin; Qian, Xin; Yuan, Xingcheng; Ye, Rui; Xia, Bisheng; Wang, Yulei

2012-12-01

122

Copper complexing capacity of waters in the magela creek system, Northern Australia  

Microsoft Academic Search

The copper?binding ligand concentration (complexing capacity) and conditional formation constants were determined in water samples collected during the 1979 dry season from five Magela Creek billabongs (waterholes) by using an amperometric titration technique at pH 6.0. In filtered water the ligand concentrations ranged from’ 0.07 ? 0.46 ?M, and the log formation constants from 7.5–8.3. The mean values were little

Barry T. Hart; Simon H. R. Davies

1981-01-01

123

Complexing capacity of natural waters carrying a great amount of suspended matter  

Microsoft Academic Search

The cadmium binding properties of waters of the superior section of the Rio de la Plata estuarine were determined over a three-year period. Samples were collected at different hydrodynamic conditions. The complexing capacity was determined by square wave anodic stripping voltammetry (SWASV). Titration curve data were analyzed using a multivariable regression.Suspended particulate matter (SPM) was identified by XR diffraction and

Yanina S. Minaberry; Gabriel J. Gordillo

2007-01-01

124

Water-holding capacity and protein denatunation in broiler breast meat  

Technology Transfer Automated Retrieval System (TEKTRAN)

The aim of this study was to investigate the impact of protein denaturation on water-holding capacity (WHC) in broiler breast meat. Breast fillets were collected at 2 h postmortem and segregated into two groups (low-WHC and high-WHC) based on pH and color. Protein solubility was measured at 6 and 24...

125

Role of protein solubility in water-holding capacity of broiler breast meat.  

Technology Transfer Automated Retrieval System (TEKTRAN)

The role muscle protein denaturation plays in determining water-holding capacity (WHC) in broiler breast meat is not well understood. Alterations in muscle protein solubility due to postmortem pH and temperature decline can be used as indicators of protein denaturation. In order to determine the i...

126

Effect of deboning time and cold storage on water-holding capacity of chicken breast meat  

Technology Transfer Automated Retrieval System (TEKTRAN)

Water-holding capacity (WHC) is a very important qualitative characteristic of meat and directly affects the yield of further processed meat and consumer acceptance of bagged pre-packaged fresh meat. Boneless skinless chicken breast meat for further processing and consumer usage is commonly deboned...

127

Leaf Photosynthetic Rate of Tropical Ferns Is Evolutionarily Linked to Water Transport Capacity  

PubMed Central

Ferns usually have relatively lower photosynthetic potential than angiosperms. However, it is unclear whether low photosynthetic potential of ferns is linked to leaf water supply. We hypothesized that there is an evolutionary association of leaf water transport capacity with photosynthesis and stomatal density in ferns. In the present study, a series of functional traits relating to leaf anatomy, hydraulics and physiology were assessed in 19 terrestrial and 11 epiphytic ferns in a common garden, and analyzed by a comparative phylogenetics method. Compared with epiphytic ferns, terrestrial ferns had higher vein density (Dvein), stomatal density (SD), stomatal conductance (gs), and photosynthetic capacity (Amax), but lower values for lower epidermal thickness (LET) and leaf thickness (LT). Across species, all traits varied significantly, but only stomatal length (SL) showed strong phylogenetic conservatism. Amax was positively correlated with Dvein and gs with and without phylogenetic corrections. SD correlated positively with Amax, Dvein and gs, with the correlation between SD and Dvein being significant after phylogenetic correction. Leaf water content showed significant correlations with LET, LT, and mesophyll thickness. Our results provide evidence that Amax of the studied ferns is linked to leaf water transport capacity, and there was an evolutionary association between water supply and demand in ferns. These findings add new insights into the evolutionary correlations among traits involving carbon and water economy in ferns. PMID:24416265

Cao, Kun-Fang; Hu, Hong; Zhang, Jiao-Lin

2014-01-01

128

Leaf photosynthetic rate of tropical ferns is evolutionarily linked to water transport capacity.  

PubMed

Ferns usually have relatively lower photosynthetic potential than angiosperms. However, it is unclear whether low photosynthetic potential of ferns is linked to leaf water supply. We hypothesized that there is an evolutionary association of leaf water transport capacity with photosynthesis and stomatal density in ferns. In the present study, a series of functional traits relating to leaf anatomy, hydraulics and physiology were assessed in 19 terrestrial and 11 epiphytic ferns in a common garden, and analyzed by a comparative phylogenetics method. Compared with epiphytic ferns, terrestrial ferns had higher vein density (Dvein), stomatal density (SD), stomatal conductance (gs), and photosynthetic capacity (Amax), but lower values for lower epidermal thickness (LET) and leaf thickness (LT). Across species, all traits varied significantly, but only stomatal length (SL) showed strong phylogenetic conservatism. Amax was positively correlated with Dvein and gs with and without phylogenetic corrections. SD correlated positively with Amax, Dvein and gs, with the correlation between SD and Dvein being significant after phylogenetic correction. Leaf water content showed significant correlations with LET, LT, and mesophyll thickness. Our results provide evidence that Amax of the studied ferns is linked to leaf water transport capacity, and there was an evolutionary association between water supply and demand in ferns. These findings add new insights into the evolutionary correlations among traits involving carbon and water economy in ferns. PMID:24416265

Zhang, Shi-Bao; Sun, Mei; Cao, Kun-Fang; Hu, Hong; Zhang, Jiao-Lin

2014-01-01

129

Storage Capacity and Water Quality of Lake Ngardok, Babeldaob Island, Republic of Palau, 1996-98  

USGS Publications Warehouse

A bathymetric survey conducted during March and April, 1996, determined the total storage capacity Lake Ngardok to be between 90 and 168 acre-feet. Elevation-surface area and elevation-capacity curves summarizing the current relations among elevation, surface area, and storage capacity were created from the bathymetric map. Rainfall and lake-elevation data collected from April 1996 to March 1998 indicated that lake levels correlated to rainfall values with lake elevation rising rapidly in response to heavy rainfall and then returning to normal levels within a few days. Mean lake elevation for the 22 month period of data was 59.5 feet which gives a mean storage capacity of 107 acre-feet and a mean surface area of 24.1 acre. A floating mat of reeds, which covered 58 percent of the lake surface area at the time of the bathymetric survey, makes true storage capacity difficult to estimate. Water-quality sampling during April 1996 and November 1997 indicated that no U.S. Environmental Protection Agency primary drinking-water standards were violated for analyzed organic and inorganic compounds and radionuclides. With suitable biological treatment, the lake water could be used for drinking-water purposes. Temperature and dissolved oxygen measurements indicated that Lake Ngardok is stratified. Given that air temperature on Palau exhibits little seasonal variation, it is likely that this pattern of stratification is persistent. As a result, complete mixing of the lake is probably rare. Near anaerobic conditions exist at the lake bottom. Low dissolved oxygen (3.2 milligrams per liter) measured at the outflow indicated that water flowing past the outflow was from the deep oxygen-depleted depths of the lake.

Yeung, Chiu Wang; Wong, Michael F.

1999-01-01

130

Capacity building in water demand management as a key component for attaining millennium development goals  

NASA Astrophysics Data System (ADS)

Successful water demand management (WDM) implementation as a component of integrated water resource management (IWRM) can play a significant role in the alleviation of poverty through more efficient use of available water resources. The urban population in Southern African cities is characterised by so-called ‘water poor’ communities who typically expend a high percentage of their household income on poor quality water. Usually they have no access to an affordable alternative source. Although WDM as a component of IWRM is not a panacea for poverty, it can help alleviate poverty by facilitating water services management by municipal water supply agencies (MWSAs) in the region. WDM is a key strategy for achieving the millennium development goals (MDGs) and, as such, should be given due attention in the preparation of national IWRM and water efficiency plans. Various studies in the Southern African region have indicated that capacity building is necessary for nations to develop IWRM and water-use efficiency plans to meet the targets set out in the MDGs. WDM education and training of water professionals and end-users is particularly important in developing countries, which are resource and information-access poor. In response to these findings, The World Conservation Union (IUCN) and its consulting partners, the Training and Instructional Design Academy of South Africa (TIDASA), and Centre for Applied Research (CAR) designed, developed and presented a pilot WDM Guideline Training Module for MWSAs as part of Phase II of IUCN’s Southern Africa regional WDM project. Pilot training was conducted in July 2004 in Lusaka, Zambia for a group of 36 participants involved in municipal water supply from nine Southern African countries. This paper looks at the links between building the capacity of professionals, operational staff and other role-players in the municipal water supply chain to implement WDM as part of broader IWRM strategies, and the subsequent potential for poverty relief resulting from more effective, efficient and equitable use and allocation of municipal water supplies.

Gumbo, Bekithemba; Forster, Laura; Arntzen, Jaap

131

Structural Change of the Mixtures of Ionic Liquid and Water Studied by Infrared Absorption Spectroscopy  

Microsoft Academic Search

Infrared absorption spectra of the mixtures of ionic liquid and water (1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM]BF4) with varying concentrations were obtained by Attenuated Total Reflection (ATR) method. Investigation of the spectra in the OH-stretch vibration range indicated the structural change of the water with the change in the concentration. At very low concentration of water, two peaks around 3600cm-1 were assigned to

Doseok Kim; Yoonnam Jeon; Jaeho Sung; Yukio Ouchi

2006-01-01

132

Blueshifting the onset of optical UV absorption for water under pressure.  

PubMed

First-principles calculations show that the optical UV absorption onset of solid water is blueshifted with increasing pressure. Across several crystal structures and a wide pressure range, the optical gap increases almost linearly with external pressure, making solid water more transparent. The origin of this unusual effect can be traced back to an increased Stark shift caused by water's electrostatic environment at smaller volumes. PMID:21635126

Hermann, Andreas; Schwerdtfeger, Peter

2011-05-01

133

Impact of MIE-Resonances on the Atmospheric Absorption of Water Clouds  

NASA Technical Reports Server (NTRS)

Clouds strongly modulate radiative transfer processes in the Earth's atmosphere. Studies, which simulate bulk properties of clouds, such as absorption, require methods that accurately account for multiple scattering among individual cloud particles. Multiple scattering processes are well described by MIE-theory, if interacting particles have a spherical shape. This is a good assumption for water droplets. Thus, simulations for water clouds (especially for interactions with solar radiation) usually apply readily available MIE-codes. The presence of different drop-sizes, however, necessitates repetitive calculations for many sizes. The usual representation by a few sizes is likely to miss contributions from densely distributed, sharp resonances. Despite their usually narrow width, integrated over the entire size-spectrum of a cloud droplet distribution, the impact of missed resonances could add up. The consideration of these resonances tends to increase cloud extinction and cloud absorption. This mechanism for a larger (than by MIE-methods predicted) solar absorption has the potential to explain observational evidence of larger than predicted cloud absorption at solar wavelengths. The presentation will address the absorption impact of added resonances for typical properties of water clouds (e.g. drop size distributions, drop concentrations and cloud geometry). Special attention will be given to scenarios with observational evidence of law than simulated solar absorption; particularly if simultaneous measurements of cloud micro- and macrophysical properties are available.

Wiscombe, W.; Kinne, S.; Nussenzveig, H.; Lau, William K. M. (Technical Monitor)

2002-01-01

134

Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants.  

PubMed

Abstract Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditional chlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaks in the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose. Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditions on the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration, liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9% was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically found to be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammonia removal rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plant membrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatment plant, also paved the way towards a larger scale application. PMID:19143342

Shao, Jiahui; Fang, Xuliang; He, Yiliang; Jin, Qiang

2008-01-01

135

ABSORPTION OF LEAD FROM DRINKING WATER WITH VARYING MINERAL CONTENT  

EPA Science Inventory

Lead (Pb) (200 ppm) was administered via drinking water to rats for nine weeks. In addition, the rats were grouped so that they received 75, 100, 150 and 250% of the minimum daily requirements (MDR) of calcium (Ca), iron (Fe), and magnesium (Mg) as required for normal growth. The...

136

Mechanisms of guanylin action on water and ion absorption at different regions of seawater eel intestine.  

PubMed

Guanylin (GN) inhibited water absorption and short-circuit current (Isc) in seawater eel intestine. Similar inhibition was observed after bumetanide, and the effect of bumetanide was abolished by GN or vice versa, suggesting that both act on the same target, Na(+)-K(+)-2Cl(-) cotransporter (NKCC), which is a key player for the Na(+)-K(+)-Cl(-) transport system responsible for water absorption in marine teleost intestine. However, effect of GN was always greater than that of bumetanide: 10% greater in middle intestine (MI) and 40% in posterior intestine (PI) for Isc, and 25% greater in MI and 34% in PI for water absorption. After treatment with GN, Isc decreased to zero, but 20-30% water absorption still remained. The remainder may be due to the Cl(-)/HCO3 (-) exchanger and Na(+)-Cl(-) cotransporter (NCC), since inhibitors for these transporters almost nullified the remaining water absorption. Quantitative PCR analysis revealed the presence of major proteins involved in water absorption; the NKCC2? and AQP1 genes whose expression was markedly upregulated after seawater acclimation. The SLC26A6 (anion exchanger) and NCC? genes were also expressed in small amounts. Consistent with the inhibitors' effect, expression of NKCC2? was MI > PI, and that of NCC? was MI < PI. The present study showed that GN not only inhibits the bumetanide-sensitive Na(+)-K(+)-Cl(-) transport system governed by NKCC2?, but also regulates unknown ion transporters different from GN-insensitive SLC26A6 and NCC. A candidate is cystic fibrosis transmembrane conductance regulator Cl(-) channel, as demonstrated in mammals, but its expression is low in eel intestine, and its role may be minor, as indicated by the small effect of its inhibitors. PMID:24990857

Ando, Masaaki; Wong, Marty K S; Takei, Yoshio

2014-09-15

137

Modeling the current and future capacity of water resources to meet water demands in the Ebro basin  

NASA Astrophysics Data System (ADS)

Worldwide studies have shown that the Mediterranean region is one of the most vulnerable areas to water crisis. The region is characterized by limited and unequally distributed water resources and increasing water demands. The Ebro catchment (85,000 km2, Spain) is representative of this context. Since the late 1970s, a negative trend in river discharge has been observed, attributed to a decrease in mean precipitation, and a rise in mean temperature and in water consumption. Finally, over 230 storage dams regulate river discharge. In this context, an integrated water resources modeling framework was developed to evaluate the current and future capacity of water resources to meet domestic and agricultural water demands as well as environmental flow requirements. The approach was driven by a conceptual rainfall-runoff model generating water supplies and by a demand driven storage dam model. The approach defines current pressures on water resources and evaluates future changes in water allocation in the medium term under climatic and water use scenarios, considering changes in population and in irrigated areas. Currently, water demands in the Ebro catchment are satisfied. In 2050, water resources are projected to decrease by 15-35% during spring and summer, leading to growing competition among users and severe water shortages for irrigated agriculture. This study provides an original approach to identify the most vulnerable regions to water use conflicts. It also highlights the interest of integrated modeling for complete analysis of the ability of water resources to meet water demands in complex change scenarios as a support for decision making.

Milano, Marianne; Ruelland, Denis; Dezetter, Alain; Fabre, Julie; Ardoin-Bardin, Sandra; Servat, Eric

2013-09-01

138

Water-controlled wealth of nations: Using Water Footprints to Estimate Nations Carrying Capacities and Demographic Sustainability  

NASA Astrophysics Data System (ADS)

Population growth is in general constrained by food production, which in turn depends on the access to water resources. At a country level, some populations use more water than they control because of their ability to import food and the virtual water required for its production. Here, we investigate the dependence of demographic growth on available water resources for exporting and importing nations. By quantifying the carrying capacity of nations based on calculations of the virtual water available through the food trade network, we point to the existence of a global water unbalance. We suggest that current export rates will not be maintained and consequently we question the long-run sustainability of the food trade system as a whole. Water rich regions are likely to soon reduce the amount of virtual water they export, thus leaving import-dependent regions without enough water to sustain their populations. We also investigate the potential impact of possible scenarios that might mitigate these effects through (1) cooperative interactions among nations whereby water rich countries maintain a tiny fraction of their food production available for export; (2) changes in consumption patterns; and (3) a positive feedback between demographic growth and technological innovations. We find that these strategies may indeed reduce the vulnerability of water-controlled societies.

Suweis, Samir; Rinaldo, Andrea; Maritan, Amos; D'Odorico, Paolo

2014-05-01

139

Effect of crop sequence, soil sample location and depth on soil water holding capacity under center pivot irrigation  

Microsoft Academic Search

This study was carried out to investigate the changes that may occur to the soil water holding capacity under center pivot irrigation systems when grown with different crop patterns over a long period of time. The changes of water holding capacity were checked as affected by crop location and depth. The study was carried out in a dominantly sandy loam

Yousef A. Al-Rumikhani

2002-01-01

140

Effects of Thinning Intensities on Soil Infiltration and Water Storage Capacity in a Chinese Pine-Oak Mixed Forest  

PubMed Central

Thinning is a crucial practice in the forest ecosystem management. The soil infiltration rate and water storage capacity of pine-oak mixed forest under three different thinning intensity treatments (15%, 30%, and 60%) were studied in Qinling Mountains of China. The thinning operations had a significant influence on soil infiltration rate and water storage capacity. The soil infiltration rate and water storage capacity in different thinning treatments followed the order of control (nonthinning): <60%, <15%, and <30%. It demonstrated that thinning operation with 30% intensity can substantially improve soil infiltration rate and water storage capacity of pine-oak mixed forest in Qinling Mountains. The soil initial infiltration rate, stable infiltration rate, and average infiltration rate in thinning 30% treatment were significantly increased by 21.1%, 104.6%, and 60.9%, compared with the control. The soil maximal water storage capacity and noncapillary water storage capacity in thinning 30% treatment were significantly improved by 20.1% and 34.3% in contrast to the control. The soil infiltration rate and water storage capacity were significantly higher in the surface layer (0~20?cm) than in the deep layers (20~40?cm and 40~60?cm). We found that the soil property was closely related to soil infiltration rate and water storage capacity. PMID:24883372

Chen, Lili; Yuan, Zhiyou; Shao, Hongbo; Wang, Dexiang; Mu, Xingmin

2014-01-01

141

Ab initio calculation of the electronic absorption spectrum of liquid water  

SciTech Connect

The electronic absorption spectrum of liquid water was investigated by coupling a one-body energy decomposition scheme to configurations generated by classical and Born-Oppenheimer Molecular Dynamics (BOMD). A Frenkel exciton Hamiltonian formalism was adopted and the excitation energies in the liquid phase were calculated with the equation of motion coupled cluster with single and double excitations method. Molecular dynamics configurations were generated by different approaches. Classical MD were carried out with the TIP4P-Ew and AMOEBA force fields. The BLYP and BLYP-D3 exchange-correlation functionals were used in BOMD. Theoretical and experimental results for the electronic absorption spectrum of liquid water are in good agreement. Emphasis is placed on the relationship between the structure of liquid water predicted by the different models and the electronic absorption spectrum. The theoretical gas to liquid phase blue-shift of the peak positions of the electronic absorption spectrum is in good agreement with experiment. The overall shift is determined by a competition between the O–H stretching of the water monomer in liquid water that leads to a red-shift and polarization effects that induce a blue-shift. The results illustrate the importance of coupling many-body energy decomposition schemes to molecular dynamics configurations to carry out ab initio calculations of the electronic properties in liquid phase.

Martiniano, Hugo F. M. C.; Galamba, Nuno [Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa (Portugal)] [Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa (Portugal); Cabral, Benedito J. Costa, E-mail: ben@cii.fc.ul.pt [Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa (Portugal) [Grupo de Física Matemática da Universidade de Lisboa, Av. Professor Gama Pinto 2, 1649-003 Lisboa (Portugal); Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa (Portugal); Instituto de Física da Universidade de São Paulo, CP 66318, 05314-970 São Paulo, SP (Brazil)

2014-04-28

142

NASA's Contribution to Water Research, Applications and Capacity Building in the America's  

NASA Astrophysics Data System (ADS)

NASA's water research, applications and capacity building activities use satellites and models to contribute to regional water information and solutions for the Americas. Free and open exchange of Earth data observations and products helps engage and improve integrated observation networks and enables national and multi-national regional water cycle research and applications. NASA satellite and modeling products provide a huge volume of valuable data extending back over 50 years across a broad range of spatial (local to global) and temporal (hourly to decadal) scales and include many products that are available in near real time (see earthdata.nasa.gov). In addition, NASA's work in hydrologic predictions are valuable for: 1) short-term and hourly data that is critical for flood and landslide warnings; 2) mid-term predictions of days to weeks useful for reservoir planning and water allocation, and 3) long term seasonal to decadal forecasts helpful for agricultural and irrigation planning, land use planning, and water infrastructure development and planning. To further accomplish these objectives NASA works to actively partner with public and private groups (e.g. federal agencies, universities, NGO's, and industry) in the U.S. and internationally to ensure the broadest use of its satellites and related information and products and to collaborate with regional end users who know the regions and their needs best. Through these data, policy and partnering activities, NASA addresses numerous water issues including water scarcity, the extreme events of drought and floods, and water quality so critical to the Americas. This presentation will outline and describe NASA's water related research, applications and capacity building programs' efforts to address the Americas' critical water challenges. This will specifically include water activities in NASA's programs in Terrestrial Hydrology (e.g., land-atmosphere feedbacks and improved stream flow estimation), Water Resources (e.g., drought, snow-pack and agriculture projects), and Disasters (e.g., flooding and landslides), and Capacity Building (e.g., 'SERVIR' science visualizations and environmental monitoring). The presentation will also demonstrate how NASA is a major contributor to water tasks and activities in GEOSS (Global Earth Observing System of Systems) in the Americas as well as USGEO and the international GEO (Group on Earth Observations) activities and to global environmental change research.

Toll, D. L.; Searby, N. D.; Doorn, B.; Lawford, R. G.; Entin, J. K.; Mohr, K. I.; Lee, C.; NASA International Water Team

2013-05-01

143

Spectral control of an alexandrite laser for an airborne water-vapor differential absorption lidar system.  

PubMed

A narrow-linewidth pulsed alexandrite laser has been greatly modified for improved spectral stability in an aircraft environment, and its operation has been evaluated in the laboratory for making water-vapor differential absorption lidar measurements. An alignment technique is described to achieve the optimum free spectral range ratio for the two étalons inserted in the alexandrite laser cavity, and the sensitivity of this ratio is analyzed. This technique drastically decreases the occurrence of mode hopping, which is commonly observed in a tunable, two-intracavity-étalon laser system. High spectral purity (> 99.85%) at 730 nm is demonstrated by the use of a water-vapor absorption line as a notch filter. The effective cross sections of 760-nm oxygen and 730-nm water-vapor absorption lines are measured at different pressures by usingthis laser, which has a finite linewidth of 0.02 cm(-1) (FWHM). It is found that for water-vapor absorption linewidths greater than 0.04 cm(-1) (HWHM), or for altitudes below 10 km, the laser line can be considered monochromatic because the measured effective absorption cross section is within 1% of the calculated monochromatic cross section. An analysis of the environmental sensitivity of the two intracavity étalons is presented, and a closed-loop computer control for active stabilization of the two intracavity étalons in the alexandrite laser is described. Using a water-vapor absorption line as a wavelength reference, we measure a long-term frequency drift (? 1.5 h) of less than 0.7 pm in the laboratory. PMID:20941182

Ponsardin, P; Higdon, N S; Grossmann, B E; Browell, E V

1994-09-20

144

Spectral control of an alexandrite laser for an airborne water-vapor differential absorption lidar system  

NASA Technical Reports Server (NTRS)

A narrow-linewidth pulsed alexandrite laser has been greatly modified for improved spectral stability in an aircraft environment, and its operation has been evaluated in the laboratory for making water-vapor differential absorption lidar measurements. An alignment technique is described to achieve the optimum free spectral range ratio for the two etalons inserted in the alexandrite laser cavity, and the sensitivity of this ratio is analyzed. This technique drastically decreases the occurrence of mode hopping, which is commonly observed in a tunable, two-intracavity-etalon laser system. High spectral purity (greater than 99.85%) at 730 nm is demonstrated by the use of a water-vapor absorption line as a notch filter. The effective cross sections of 760-nm oxygen and 730-nm water-vapor absorption lines are measured at different pressures by using this laser, which has a finite linewidth of 0.02 cm(exp -1) (FWHM). It is found that for water-vapor absorption linewidths greater than 0.04 cm(exp -1) (HWHM), or for altitudes below 10 km, the laser line can be considered monochromatic because the measured effective absorption cross section is within 1% of the calculated monochromatic cross section. An analysis of the environmental sensitivity of the two intracavity etalons is presented, and a closed-loop computer control for active stabilization of the two intracavity etalons in the alexandrite laser is described. Using a water-vapor absorption line as a wavelength reference, we measure a long-term frequency drift (approximately 1.5 h) of less than 0.7 pm in the laboratory.

Ponsardin, Patrick; Grossmann, Benoist E.; Browell, Edward V.

1994-01-01

145

Liquid water absorption and scattering effects in DOAS retrievals over oceans  

NASA Astrophysics Data System (ADS)

It is well-known that spectral effects of liquid water are present in absorption (DOAS) measurements above the ocean and insufficiently removed liquid water structures may interfere with trace gas absorptions leading to wrong (sometimes even non-physical) results. Currently available literature cross-sections of liquid water absorption are provided in coarser resolution than hyperspectral DOAS applications require and Vibrational Raman Scattering (VRS) is mostly unconsidered or compensated for using simulated pseudo cross-sections from radiative transfer modelling. During the ship-based TransBrom campaign across the western Pacific in October 2009, MAX-DOAS measurements were performed into very clear natural waters achieving underwater light paths of up to 50 m. From these measurements, the retrieval of a residual (H2Ores) spectrum is presented compensating simultaneously for insufficiencies of the liquid water absorption cross-section and broad-banded VRS structures. Small-banded (Ring) structures caused by VRS were found to be very efficiently compensated for by the intensity offset (straylight) correction included in the DOAS fit. In the MAX-DOAS tropospheric NO2 retrieval, this method was able to compensate entirely for all liquid water effects that decrease the fit quality. This was not achieved using a liquid water cross-section in combination with a simulated VRS spectrum. Typical values of improvement depend on the measurement's contamination with liquid water structures and range from ? 30% for measurements slightly towards the water surface to several percent in small angles above the horizon. Furthermore, the H2Ores spectrum was found to prevent misfits of NO2 slant columns especially for very low NO2 scenarios and thus increase the reliability of the fit. In test fits on OMI satellite data, the H2Ores spectrum was found selectively above ocean surfaces where it leads to fit quality improvements of up to 6-18%.

Peters, E.; Wittrock, F.; Richter, A.; Alvarado, L. M. A.; Rozanov, V. V.; Burrows, J. P.

2014-05-01

146

Impact of the hydraulic capacity of plants on water and carbon fluxes in tropical South America  

NASA Astrophysics Data System (ADS)

Angiosperms (flowering plants) have higher transpirational capacities than any other plants. Here we use climate model simulation to test the hypothesis that the high transpirational capacity of angiosperms plays a unique role in the maintenance of tropical rainforest. Their elevated transpiration rates are shown to increase recycling of precipitation up to ˜300 mm/yr (˜20% of total precipitation) averaged over the whole of tropical South America and to increase the wet season duration over the Amazon basin. Transpiration triggers convection by increasing moisture in the boundary layer and thereby decreasing atmospheric stability. If the moisture content of the boundary layer is sufficient, a double Intertropical Convergence Zone (ITCZ) is generated in October around 60°W-50°W, as observed in present-day climate, and the eastern part of the Amazon basin becomes wet (˜200 mm/month of precipitation). This double ITCZ is lost, however, and the region becomes dry (<50 mm/month of precipitation) in the absence of full angiosperm transpiration. Although higher water use efficiency is usually associated with plants with lower transpiration rates, water use efficiency actually increases with higher hydraulic capacity in our simulations as a result of the higher humidity and, thus, lower vapor pressure gradient between the intercellular air space within the leaf and the external atmosphere. We speculate that the high transpirational capacity of angiosperms played a significant role in the expansion of tropical rain forest.

Lee, Jung-Eun; Boyce, Kevin

2010-12-01

147

The development of an integrating cavity absorption meter to measure optical absorption of pure waters and suspended particulates  

E-print Network

an instrument capable of measuring optical absorption independent of scattering effects. The measurement of optical absorption has always been complicated by scattering effects. The most common and perhaps simplest method of measuring absorption is based... Model V cross section parallel to the Z-axis . . 18 10 Model V cross section transverse to the Z-axis . 18 Absorption of Irgalan Black samples measured in a Cary 219 spectrophotometer. . . . . . . 19 12 Absorption vs the ratio (Sl/SO) at 630 nm...

Pope, Robin Merl

1990-01-01

148

30 CFR 75.1107-7 - Water spray devices; capacity; water supply; minimum requirements.  

(a) Where water spray devices are used on unattended underground equipment the rate of flow shall be at least 0.25 gallon per minute per square foot over the top surface area of the equipment and the supply of water shall be adequate to provide the required flow of water for 10...

2014-07-01

149

Bathymetric surveys and area/capacity tables of water-supply reservoirs for the city of Cameron, Missouri, July 2013  

USGS Publications Warehouse

Years of sediment accumulation and dry conditions in recent years have led to the decline of water levels and capacities for many water-supply reservoirs in Missouri, and have caused renewed interest in modernizing outdated area/capacity tables for these reservoirs. The U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, surveyed the bathymetry of the four water-supply reservoirs used by the city of Cameron, Missouri, in July 2013. The data were used to provide water managers with area/capacity tables and bathymetric maps of the reservoirs at the time of the surveys.

Huizinga, Richard J.

2014-01-01

150

Studies of Water Absorption Behavior of Plant Fibers at Different Temperatures  

NASA Astrophysics Data System (ADS)

Moisture absorption of natural fiber plastic composites is one major concern in their outdoor applications. The absorbed moisture has many detrimental effects on the mechanical performance of these composites. A knowledge of the moisture diffusivity, permeability, and solubility is very much essential for the application of natural fibers as an excellent reinforcement in polymers. An effort has been made to study the water absorption behavior of some natural fibers such as bowstring hemp, okra, and betel nut at different temperatures to improve the long-term performance of composites reinforced with these fibers. The gain in moisture content in the fibers due to water absorption was measured as a function of exposure time at temperatures ranging from 300 K to 340 K. The thermodynamic parameters of the sorption process, such as diffusion coefficients and corresponding activation energies, were estimated.

Saikia, Dip

2010-05-01

151

State-of-the-Art Review on Crystallization Control Technologies for water/LiBr Absorption Heat Pumps  

SciTech Connect

The key technical barrier to using water/lithium bromide (LiBr) as the working fluid in aircooled absorption chillers and absorption heat-pump systems is the risk of crystallization when the absorber temperature rises at fixed evaporating pressure. This article reviews various crystallization control technologies available to resolve this problem: chemical inhibitors, heat and mass transfer enhancement methods, thermodynamic cycle modifications, and absorption system-control strategies. Other approaches, such as boosting absorber pressure and J-tube technology, are reviewed as well. This review can help guide future efforts to develop water/LiBr air-cooled absorption chillers and absorption heatpump systems.

Wang, Kai [ORNL; Abdelaziz, Omar [ORNL; Kisari, Padmaja [ORNL; Vineyard, Edward Allan [ORNL

2011-01-01

152

NASA LASE water vapor differential absorption lidar measurements and performance evaluation  

Microsoft Academic Search

The Lidar Atmospheric Sensing Experiment (LASE) is a highly engineered and autonomous Differential Absorption Lidar (DIAL) system developed at NASA Langley Research Center (LaRC) to measure high-resolution water vapor and aerosol profiles in the troposphere. LASE is being developed as a precursor to the deployment of a spaceborne DIAL system for global measurement of high-resolution water vapor profiles. The LASE

S. Ismail; E. V. Browell

1995-01-01

153

Mapping Canadian boreal forest vegetation using pigment and water absorption features derived from the AVIRIS sensor  

Microsoft Academic Search

Using imagery of the Canadian boreal forest, we explored the ability of the Airborne Visible Infrared Imaging Spectrometer (AVIRIS) to map vegetation type by taking advantage of pigment and water absorption features. Two techniques were exploited. In the first classification routine, laboratory-acquired leaf spectra representing different \\

David A. Fuentes; John A. Gamon; Hong-Lie Qiu; Daniel A. Sims; Dar A. Roberts

2001-01-01

154

Ammonia absorption from a bubble expanding at a submerged orifice into water  

Microsoft Academic Search

To investigate the mechanism of gas absorption from a bubble containing soluble and insoluble components, a gaseous mixture of ammonia and nitrogen was bubbled into water. The growth curve, volume, surface area and shape of the growing bubbles were measured with parameters such as inlet gas composition, gas flow rate and gas chamber volume. The bubble volume decreased with the

Koichi Terasaka; Junko Oka; Hideki Tsuge

2002-01-01

155

Forest structure and biomass estimates derived from red edge and water absorption geometry using AVIRIS data  

Microsoft Academic Search

Geometric analysis of spectral signatures collected from known forest sites using narrow spectral bands in the red-edge and five water absorption regions are the basis for developing ratios to estimate forest biomass and canopy structure. The study area used to test the methodology was located within Congaree Swamp National Monument in central South Carolina. This is one of the oldest

Nelson Wellausen Dias

2001-01-01

156

TPS/PCL composite reinforced with treated sisal fibers: property, biodegradation and water-absorption  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sisal fibers bleached with sodium-hydroxide followed by hydrogen peroxide treatment were incorporated in a thermoplastic starch;-polycaprolactone (TPS/PCL) blend via extrusion processing and examined for their property, biodegradability and water-absorption. Scanning electron microscopy revealed wel...

157

Stopping-power and mass energy-absorption coefficient ratios for Solid Water  

Microsoft Academic Search

The AAPM Task Group 21 protocol provides tables of ratios of average restricted stopping powers and ratios of mean energy-absorption coefficients for different materials. These values were based on the work of Cunningham and Schulz. We have calculated these quantities for Solid Water (manufactured by RMI), using the same x-ray spectra and method as that used by Cunningham and Schulz.

Anthony K. Ho; B. R. Paliwal

1986-01-01

158

Radiation modification of water absorption of cassava starch by acrylic acid/acrylamide  

NASA Astrophysics Data System (ADS)

Graft copolymerizations of acrylamide and/or acrylic acid onto cassava starch by a simultaneous irradiation technique using gamma-rays as the initiator were studied with regard to various parameters of importance: the monomer-to-cassava starch ratio, total dose (kGy), dose rate (kGy h -1), acrylamide-to-acrylic acid ratio, and the addition of nitric acid and maleic acid as the additives. Grafting parameters were determined in relation to the water absorption of the saponified graft copolymer. The water absorption of the saponified graft copolymer in salt and buffer solutions of different ionic strengths was also measured, from which the superabsorbent properties are found to be pH sensitive. The starch graft copolymers of acrylamide and acrylic acid give higher water absorption than the starch graft copolymers of either acrylamide or acrylic acid alone. The porosity of the saponified starch graft copolymers prepared by the acrylamide/acrylic acid ratios of 70:30 and 50:50 was much higher than the porosity of copolymers in terms of fine networks. Ionic strength and multi-oxidation states of the saline and buffer solutions markedly decreased the water absorption of the saponified cassava starch grafted superabsorbent polymers.

Kiatkamjornwong, Suda; Chomsaksakul, Wararuk; Sonsuk, Manit

2000-10-01

159

Electronic structure of liquid water from polarization-dependent two-photon absorption spectroscopy  

E-print Network

Two-photon absorption (2PA) spectroscopy in the range from 7 to 10 eV provides new insight on the electronic structure of liquid water. Continuous 2PA spectra are obtained via the pump-probe technique, using broadband probe pulses to record...

Elles, Christopher G.; Rivera, Christopher A.; Zhang, Yuyuan; Pieniazek, Piotr A.; Bradforth, Stephen E.

2009-02-26

160

Predicting inhomogeneous water absorption in an ionic diblock polymer membrane  

NASA Astrophysics Data System (ADS)

Fuel cells convert fuel directly into electrical power. Their performance depends on a permeable (yet strong) membrane to allow ion conduction (while preventing combustion). Anion-exchange membrane fuel-cells are especially economical to produce, but technological hurdles currently limit durability and OH^- conductivity of the membrane. One solution to these problems is a diblock morphology. Layers of stiff hydrophobic polymer provide structure, while interspersed layers of polyelectrolyte provide avenues for conduction. Previously, little was known about the structure within the conducting layer. We adapted Scheutjens-Fleer polymer-brush theory to a lamellar geometry. The calculation tells where the polyelectrolytes congregate within a lamella, and hence how conduction occurs. This talk focuses on a new diblock material, PMB-PVBTMA. We show how the features of the material determine the intra-lamellar structure. We conclude that at low humidity, the bulkiness of PVBTMA causes it to adopt a near-uniform distribution within the conducting block. At high humidity, however, a phase separation may induce abrupt water channels. Understanding the architecture within the conducting layer will help guide research into better anion-exchange membranes materials.

Herbst, Daniel; Witten, Thomas

2013-03-01

161

Application of multiobjective optimization to scheduling capacity expansion of urban water resource systems  

NASA Astrophysics Data System (ADS)

population increase in urban areas is likely to result in a deterioration of drought security and level of service provided by urban water resource systems. One way to cope with this is to optimally schedule the expansion of system resources. However, the high capital costs and environmental impacts associated with expanding or building major water infrastructure warrant the investigation of scheduling system operational options such as reservoir operating rules, demand reduction policies, and drought contingency plans, as a way of delaying or avoiding the expansion of water supply infrastructure. Traditionally, minimizing cost has been considered the primary objective in scheduling capacity expansion problems. In this paper, we consider some of the drawbacks of this approach. It is shown that there is no guarantee that the social burden of coping with drought emergencies is shared equitably across planning stages. In addition, it is shown that previous approaches do not adequately exploit the benefits of joint optimization of operational and infrastructure options and do not adequately address the need for the high level of drought security expected for urban systems. To address these shortcomings, a new multiobjective optimization approach to scheduling capacity expansion in an urban water resource system is presented and illustrated in a case study involving the bulk water supply system for Canberra. The results show that the multiobjective approach can address the temporal equity issue of sharing the burden of drought emergencies and that joint optimization of operational and infrastructure options can provide solutions superior to those just involving infrastructure options.

Mortazavi-Naeini, Mohammad; Kuczera, George; Cui, Lijie

2014-06-01

162

Aggregating available soil water holding capacity data for crop yield models  

NASA Technical Reports Server (NTRS)

The total amount of water available to plants that is held against gravity in a soil is usually estimated as the amount present at -0.03 MPa average water potential minus the amount present at -1.5 MPa water potential. This value, designated available water-holding capacity (AWHC), is a very important soil characteristic that is strongly and positively correlated to the inherent productivity of soils. In various applications, including assessing soil moisture status over large areas, it is necessary to group soil types or series as to their productivity. Current methods to classify AWHC of soils consider only total capacity of soil profiles and thus may group together soils which differ greatly in AWHC as a function of depth in the profile. A general approach for evaluating quantitatively the multidimensional nature of AWHC in soils is described. Data for 902 soil profiles, representing 184 soil series, in Indiana were obtained from the Soil Characterization Laboratory at Purdue University. The AWHC for each of ten 150-mm layers in each soil was established, based on soil texture and parent material. A multivariate clustering procedure was used to classify each soil profile into one of 4, 8, or 12 classes based upon ten-dimensional AWHC values. The optimum number of classes depends on the range of AWHC in the population of oil profiles analyzed and on the sensitivity of a crop to differences in distribution of water within the soil profile.

Seubert, C. E.; Daughtry, C. S. T.; Holt, D. A.; Baumgardner, M. F.

1984-01-01

163

Wide absorption spectrum measuring methods by DFB-LDs in water vapor detection system  

NASA Astrophysics Data System (ADS)

Two measuring methods of the wide absorption spectrum by distributed feedback laser diodes (DFB-LDs) are presented in detecting the water vapor absorption line. One is the subsection scanning method, and it takes advantage of the wide spectrum tuning range by the temperature modulation and fast spectrum tuning speed by current modulation. Specifically, this method is realized by dividing a target spectral region into several sections which correspond to the specific temperature of DFB-LD, scanning every section by current modulation for hundreds times, and averaging the data to raise the signal to noise ratio (SNR), then combining all sections to get the whole spectrum. An accuracy of 10 ppmv had been obtained in the measurement of water vapor with a 10-cm path length by this method. Another is data fitting method, based on the absorption line-shape function; the absorption line can be described by fitting with partial measured data. The fitting absorption line was fitted well with the measured data, and the square of correlation coefficient (R-square) was no less than 0.99.

Liu, Y. N.; Chang, J.; Lian, J.; Wang, Q.; Lv, G. P.; Wang, W. J.; Liu, Z.; Liu, X. Z.; Zhang, S. S.; Wang, Z. L.; Jiang, S.; Zhu, C. G.; Wei, W.; Sun, B. N.

2014-09-01

164

Wide absorption spectrum measuring methods by DFB-LDs in water vapor detection system  

NASA Astrophysics Data System (ADS)

Two measuring methods of wide absorption spectrum by DFB-LDs are presented in detecting water vapor absorption line. One is subsection scanning method, it takes advantage of wide spectrum tuning range by temperature modulation and fast spectrum tuning speed by current modulation, specifically, this method is realized by dividing a target spectral region into several sections which corresponding to specific temperature of DFB-LD, and scanning every section by current modulation for hundreds times and average the data to raise SNR, combining all sections to get the whole spectrum. An accuracy of 10 ppmv had been obtained in the measurement of water vapor with a 10-cm path length by this method. Another is data fitting method, based on absorption line-shape function, the absorption line can be described by fitting with partial measured data. The fitting absorption line is fitted well with the measured data, and the square of correlation coefficient (R-square) is no less than 0.99.

Liu, Y. N.; Chang, J.; Lian, J.; Wang, Q.; Lv, G. P.; Wang, W. J.; Liu, Z.; Liu, X. Z.; Zhang, S. S.; Wang, Z. L.; Jiang, S.; Zhu, C. G.; Wei, W.; Sun, B. N.

2013-09-01

165

Estimating Available Water Capacity in the Lower Mekong River Basin by Integrating GRACE Observations into a Land Surface Model  

NASA Astrophysics Data System (ADS)

The Gravity Recovery and Climate Experiment (GRACE) data has provided global monthly time series data on water storage change at one-degree resolution over the past decade (2003-2012). Available Water Capacity (AWC) of the soil in watersheds is useful for estimating potential groundwater recharge. The dynamics of Terrestrial Water Storage (TWS) are constrained by the Available Water Capacity, related to field capacity and wilting point, and reflect regional water dynamics. In the Lower Mekong River Basin, the Available Water Capacity map being applied by the Mekong River Commission (MRC) is in need of update. The goal of this study is to assimilate TWS from GRACE data using an Ensemble Kalman Smoother and the NASA Catchment Land Surface Model (CLSM) over a sub-basin of the Lower Mekong River Basin. In this way, the water holding capacity of the sub-basin is constrained. The calculated AWC is compared with AWC from MRC. Furthermore, the calculated AWC will be validated using the Soil and Water Assessment Tool (SWAT), which requires AWC as an adjusted parameter on discharge calibration. The implications of the available water capacity on watershed management will be discussed.

Hung, C. J.; Bolten, J. D.; Lakshmi, V.; Wilson, R.; Strauch, K.; Doyle, T.; Habib, S.; Toll, D. L.; Srinivasan, R.

2013-12-01

166

Improvement of the Performance for an Absorption Refrigeration System with Lithium bromide-water as Refrigerant by Increasing Absorption Pressure  

E-print Network

, the low COP of the absorption machine was limited seriously to compete with the refrigeration machine that is drove by electricity. Therefore, most researchers focus their attention on the improvement of performance of the absorption system through many...

Xie, G.; Sheng, G.; Li, G.; Pan, S.

2006-01-01

167

Accelerated Capacity Development in Water Resources Education: the experiences of the Ethiopian Institute of Water Resources  

NASA Astrophysics Data System (ADS)

Ethiopia recently recognises that the water resources development is the major entry point in poverty alleviation and sustainable development. Water in Ethiopia plays a key role in the Water-Energy-Food-nexus. Over 98% of the electricity in the country is generated using hydropower and yet about 2000 MW has been developed. Out of the 3.5 Mha potentially irrigable land, only 0.25 Mha has been developed to date. Access to drinking water supply coverage is among the lowest in the world. One of the limiting factors in harnessing the resource base is the absence of water professionals to face the fast growing demand in education, research, development in the water sector. Recognising this, in collaboration with University of Connecticut of the United States, Addis Ababa University launched the Ethiopian Institute of Water Resources (EIWR) by enrolling 18 PhD and 24 MSc students. The program is unique in that much of the course instructors are coming from US and European Universities, but deliver courses together with Ethiopian collaborators. This is supposed to facilitate knowledge and experience transfer from the US/EU scientist to Ethiopian counterparts. The theses/dissertations are designed to focus on Ethiopia's immediate hydrological problems on selected basins, and will be coordinated by three advisors for each PhD - one from US/EU, one from Ethiopian Universities, and one water professional from the sector. We report here the lessons learned in setting up the EIWR institute and the education program.

Alamirew, T.; Mekonnen, G.; Viglione, A.

2012-04-01

168

Fractional water allocation and reservoir capacity sharing concepts: An adaptation for the Komati Basin  

NASA Astrophysics Data System (ADS)

This paper presents an adaptation of fractional water allocation and reservoir capacity sharing (FWARCS) concepts for application in the Komati Basin, a river system shared between South Africa, Swaziland and Mozambique. Many traditional methods for allocating water are based on volume-per-unit-time allocation that is supplied at some level of assurance and managed using priority-based reservoir and river system operating rules, as well as on the “use it or lose it” principle, which is considered exclusive by water users as it leaves them out of the management of their water allocations. In the Komati Basin, these traditional methods of water allocation led to frequent conflicts among users and with water managers. However, the introduction of the modified FWARCS, which assigns available water in the system to water users according to the proportions of their water entitlements and allows water to be banked in reservoirs, appears to be a solution to some of these problems. This method allows water users to decide when and how much of that entitlement they may use. Since the implementation of the modified FWARCS technique in the Komati Basin in 2002, the regulation, transparency and efficiency of operating the system improved and subsequently the number of disputes over water has declined. South Africa improved from an overuse of 8.2 Mm 3 in 2002/03 water year to realize a saving of 29.5 Mm 3 in 2005/06. Similarly, Swaziland improved from an overuse of 3.9 Mm 3 in 2002/03 to achieve a saving of 14.6 Mm 3 in 2005/06. Users have recognised and embraced the transparency and flexibility of the modified FWARCS. They choose, as the need and opportunity arise, when and how much water they utilise, whether to “bank” and/or “trade” the water they save subject to the conditions of their entitlements. The implementation of the modified FWARCS was also made successful by the existence of proper institutional structures, appropriate decision support tools, good water measurement infrastructure and reliable water accounting systems. The establishment, development and utilization of these elements of water management, as well as the challenges encountered in relation to the adoption of modified FWARCS in the Komati Basin are discussed in this paper.

Dlamini, Enoch M.; Dhlamini, Sidney; Mthimkhulu, Sindy

169

Measurement methods in trace water vapor concentration detection system based on direct absorption spectroscopy  

NASA Astrophysics Data System (ADS)

In trace water vapor direct absorption spectroscopy, the absorption signal is buried in noise and up and downs of the light intensity, an effective signal extraction method is vital. In the basis of double-beam differential absorption, division method in voltage and an approach based on balanced ratiometer detection (BRD) were studied. Voltage division has an excellent stability to temperature variation, mechanical extrusion and fiber bend loss. As to the BRD method, it has an outstanding self-adjusting capability and it can also avoid an excess phase difference caused by current-to-voltage converting circuit, thus this method has a high sensitivity. Furthermore, a so called dual-peak method based on the differential value of two adjacent absorption lines is introduced, the differential value proved has a linear relation with water vapor concentration, and this method provides a way to measure the concentration at high pressure. In addition, the influence of water vapor inside the optical components has been discussed.

Lv, G. P.; Chang, J.; Zhang, S. S.; Wang, Q. P.; Liu, Y. N.; Liu, Z.; Wang, Q.; Wang, W. J.; Wang, Z. L.; Jiang, S.; Zhu, C. G.; Wei, W.

2013-09-01

170

Differential absorption lidar measurements of atmospheric water vapor using an optical parametric oscillator source.  

PubMed

A differential absorption lidar system based on a continuously tunable Nd:YAG pumped optical parametric oscillator source is described which is capable of range-resolved measurements of atmospheric species with absorption bands in the 1.4-4.0-mum range. The system has been used to measure atmospheric water vapor at ranges of up to 1 km. The actual and predicted performances of the system are compared, and some of the problems peculiar to continuously tunable IR sources, such as non-negligible linewidth and the need for accurate wavelength setting, are analyzed. PMID:20401088

Brassington, D J

1982-12-15

171

Nanosheet-structured boron nitride spheres with a versatile adsorption capacity for water cleaning.  

PubMed

Here, we report the synthesis of nanosheet-structured boron nitride spheres (NSBNSs) by a catalyzing thermal evaporation method from solid B powders. The NSBNSs consist of radially oriented ultrathin nanosheets with the sheet edges oriented on the surface. Formation of this unique structure occurs only at a certain reaction temperature. The diameter from 4 ?m to 700 nm and the nanosheet thickness from 9.1 to 3.1 nm of the NSBNSs can be well-controlled by appropriately changing the mass ratio of boron powders and catalyst. The NSBNSs possess versatile adsorption capacity, exhibiting excellent adsorption performance for oil, dyes, and heavy metal ions from water. The oil uptake reaches 7.8 times its own weight. The adsorption capacities for malachite green and methylene blue are 324 and 233 mg/g, while those for Cu(2+), Pb(2+), and Cd(2+) are 678.7, 536.7, and 107.0 mg/g, respectively. The adsorption capacities of the NSBNSs for Cu(2+) and Pb(2+) are higher or much higher than those of the adsorbents reported previously. These results demonstrate the great potential of NSBNSs for water treatment and cleaning. PMID:25552343

Liu, Fei; Yu, Jie; Ji, Xixi; Qian, Muqi

2015-01-28

172

Determination of traces of silver in waters by anion exchange and atomic absorption spectrophotometry  

USGS Publications Warehouse

A method has been developed for the accurate determination of 0.1-1 ??g of silver per liter of water. The method permits stabilization of silver in water without loss to container walls. Optimum conditions have been established for the complete recovery of silver from water with an anion-exchange column, for quantitative elution of silver from the resin, and for measurement of silver by atomic absorption spectrophotometry after chelation with ammonium pyrrolidine dithiocarbamate and extraction of the chelate with MIBK. Silver in the 1-10 ??g 1 range can be determined by extraction without pre-concentration on an ion-exchange resin. ?? 1969.

Chao, T.T.; Fishman, M.J.; Ball, J.W.

1969-01-01

173

Biodestruction of strongly swelling polymer hydrogels and its effect on the water retention capacity of soils  

NASA Astrophysics Data System (ADS)

The biodestruction of strongly swelling polymer hydrogels (water adsorbing soil conditioners of the new generation) has been studied at the quantitative level using original mathematical models. In laboratory experiments, a relationship between the hydrogel degradation rate and the temperature has been obtained, and the effect of the biodestruction on the water retention curve of soil compositions with hydrogels (used as an index of their water retention capacity) has been assessed. From the automatic monitoring data of the temperature regime of soils, the potential biodestruction of hydrogels has been predicted for different climatic conditions. The loss of hydrogels during three months of the vegetation period because of destruction can exceed 30% of their initial content in irrigated agriculture under arid climatic conditions and more than 10% under humid climatic conditions. Thus, the biodestruction of hydrogels is one of the most important factors decreasing their efficiency under actual soil conditions.

Smagin, A. V.; Sadovnikova, N. B.; Smagina, M. V.

2014-06-01

174

Complexing capacity of natural waters carrying a great amount of suspended matter.  

PubMed

The cadmium binding properties of waters of the superior section of the Rio de la Plata estuarine were determined over a three-year period. Samples were collected at different hydrodynamic conditions. The complexing capacity was determined by square wave anodic stripping voltammetry (SWASV). Titration curve data were analyzed using a multivariable regression. Suspended particulate matter (SPM) was identified by XR diffraction and FTIR. These analyses showed that SPM principal components are clays (illite, montmorillonite and chlorite). The study was applied to the untreated, filtered and centrifuged fractions of each sample at the pH of the natural waters and at pH 1. The results show that the contribution of dissolved organic matter to the complexing capacity is negligible when compared with SPM. At natural pH, the complexing capacity of filtered and untreated fractions can be described by considering two kinds of binding sites. The associated conditional binding constants are independent of the concentration of suspended matter. Their average logarithms are ca. 6.5 and ca. 4.4. The total concentration of binding sites (S(T)) is in microM range, which is about three orders of magnitude higher than that reported for most of the studied estuaries. This difference is explained on the basis of the great amount of SPM. Hydrodynamic conditions produce variations in the concentration and composition of the SPM. At pH 1 samples still exhibit an important complexing capacity with only one binding site with log K(cond) ca. 5.4. These differences could be attributed to superficial modifications that take place at very low pH. PMID:17572474

Minaberry, Yanina S; Gordillo, Gabriel J

2007-11-01

175

A yearlong study of water-soluble organic carbon in Beijing II: Light absorption properties  

NASA Astrophysics Data System (ADS)

Light absorption properties of water-soluble organic carbon (WSOC) in Beijing were investigated by 24 h-averaged fine particulate matter (PM2.5) samples collected from October 2010 to November 2011. The light absorption spectra of WSOC exhibited strong wavelength dependence such that the absorption Ångstrom exponent was approximately 7.5. The light absorption at 365 nm (Abs365), which is typically used as a proxy of water-soluble brown carbon, was found to correlate strongly with WSOC (R2 > 0.75, p < 0.01). Moreover, the correlation between Abs365 and levoglucosan (especially in fall and winter) indicated that biomass burning could contribute significantly to water-soluble brown carbon. Source apportionment with Positive Matrix Factorization (PMF) model showed that biomass burning and mixed sources contributed 58.0% and 20.8% to total Abs365, compared with 21.2% from WSOC associated with sulfate and oxalate. The mass absorption efficiency (MAE) of WSOC in Beijing showed distinct temporal variations (averaging 1.26 m2/g and 0.51 m2/g during winter and summer, respectively), and was approximately 2-3 times the values of that observed in the southeastern United States, but was substantially lower than the summertime results from Los Angeles. Influence factors responsible for the temporal and spatial variations of MAE were investigated. MAE were calculated for each PMF factor. It was found that the MAE for WSOC from biomass burning (1.19 m2/g) and mixed primary sources (2.89 m2/g) was much higher than that of WSOC associated with sulfate or oxalate (0.32-0.33 m2/g) in Beijing. In addition, it was concluded that differences in the precursors of WSOC might also be responsible for the observed variation of MAE such that WSOC associated with anthropogenic precursors are more light-absorbing compared with WSOC biogenic sources.

Du, Zhenyu; He, Kebin; Cheng, Yuan; Duan, Fengkui; Ma, Yongliang; Liu, Jiumeng; Zhang, Xiaolu; Zheng, Mei; Weber, Rodney

2014-06-01

176

Influence of molecular weight on oral absorption of water soluble chitosans.  

PubMed

Chitosan, a cationic polysaccharide, has been widely employed as dietary supplement and in pharmacological and biomedical applications. Although numerous studies have focused on its applications as pharmaceutical excipients or bioactive reagents, molecular weight (MW)-dependent pharmaceutical and bioactive properties remain unclear. As a preliminary study, we investigated the MW-dependent Caco-2 cell layer transport phenomena (in vitro) and intestinal absorption patterns after oral administration (in vivo) of water-soluble chitosans (WSCs). The absorption of chitosan was significantly influenced by its MW. As the MW increases, the absorption decreases. Compared to high-MW chitosan (WSC 230K, MW=230 kDa), absorption profiles were observed to increase more than 23 and 25 times with WSC 3.8K (MW=3.8 kDa) in both in vitro and in vivo transport experiments, respectively. Furthermore, the chitosans showed concentration- and MW-dependent cytotoxic effects, and the chitosan oligosaccharides (MW<10 kDa) showed negligible cytotoxic effect on the Caco-2 cells. In consideration with safety and absorption profiles, chitosan oligosaccharides may be considered as safe and potential candidates for pharmaceutical and biomedical applications. PMID:15653159

Chae, Su Young; Jang, Mi-Kyeong; Nah, Jae-Woon

2005-02-01

177

Estimating a Global Hydrological Carrying Capacity Using GRACE Observed Water Stress  

NASA Astrophysics Data System (ADS)

Global population is expected to reach 9 billion people by the year 2050, causing increased demands for water and potential threats to human security. This study attempts to frame the overpopulation problem through a hydrological resources lens by hypothesizing that observed groundwater trends should be directly attributed to human water consumption. This study analyzes the relationships between available blue water, population, and cropland area on a global scale. Using satellite data from NASA's Gravity Recovery and Climate Experiment (GRACE) along with land surface model data from the Global Land Data Assimilation System (GLDAS), a global groundwater depletion trend is isolated, the validity of which has been verified in many regional studies. By using the inherent distributions of these relationships, we estimate the regional populations that have exceeded their local hydrological carrying capacity. Globally, these populations sum to ~3.5 billion people that are living in presently water-stressed or potentially water-scarce regions, and we estimate total cropland is exceeding a sustainable threshold by about 80 million km^2. Key study areas such as the North China Plain, northwest India, and Mexico City were qualitatively chosen for further analysis of regional water resources and policies, based on our distributions of water stress. These case studies are used to verify the groundwater level changes seen in the GRACE trend . Tfor the many populous, arid regions of the world that have already begun to experience the strains of high water demand.he many populous, arid regions of the world have already begun to experience the strains of high water demand. It will take a global cooperative effort of improving domestic and agricultural use efficiency, and summoning a political will to prioritize environmental issues to adapt to a thirstier planet. Global Groundwater Depletion Trend (Mar 2003-Dec 2011)

An, K.; Reager, J. T.; Famiglietti, J. S.

2013-12-01

178

Water vapour absorption in the clear atmosphere of a Neptune-sized exoplanet  

NASA Astrophysics Data System (ADS)

Transmission spectroscopy has so far detected atomic and molecular absorption in Jupiter-sized exoplanets, but intense efforts to measure molecular absorption in the atmospheres of smaller (Neptune-sized) planets during transits have revealed only featureless spectra. From this it was concluded that the majority of small, warm planets evolve to sustain atmospheres with high mean molecular weights (little hydrogen), opaque clouds or scattering hazes, reducing our ability to observe the composition of these atmospheres. Here we report observations of the transmission spectrum of the exoplanet HAT-P-11b (which has a radius about four times that of Earth) from the optical wavelength range to the infrared. We detected water vapour absorption at a wavelength of 1.4 micrometres. The amplitude of the water absorption (approximately 250 parts per million) indicates that the planetary atmosphere is predominantly clear down to an altitude corresponding to about 1 millibar, and sufficiently rich in hydrogen to have a large scale height (over which the atmospheric pressure varies by a factor of e). The spectrum is indicative of a planetary atmosphere in which the abundance of heavy elements is no greater than about 700 times the solar value. This is in good agreement with the core-accretion theory of planet formation, in which a gas giant planet acquires its atmosphere by accreting hydrogen-rich gas directly from the protoplanetary nebula onto a large rocky or icy core.

Fraine, Jonathan; Deming, Drake; Benneke, Bjorn; Knutson, Heather; Jordán, Andrés; Espinoza, Néstor; Madhusudhan, Nikku; Wilkins, Ashlee; Todorov, Kamen

2014-09-01

179

Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation  

SciTech Connect

This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose of this work was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. PNL researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH{sub 4}{sup +}). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

Anheier, N.C. Jr.; McDonald, C.E.; Cuta, J.M.; Cuta, F.M.; Olsen, K.B.

1995-05-01

180

Water vapor heterogeneity related to tropopause folds over the North Atlantic revealed by airborne water vapor differential absorption lidar  

Microsoft Academic Search

Airborne differential absorption lidar (DIAL) measurements of tropospheric water vapor and aerosol\\/clouds are presented from transfers across the North Atlantic on 13-15 May and 16-18 June 2002. The intense dynamical activity over the Atlantic is reflected in complex structures like deep tropopause folds, extended dry layers, and tilted aerosol filaments. Intrusions with H2O mixing ratios below 0.03 g kg-1 regularly

H. Flentje; A. Dörnbrack; G. Ehret; A. Fix; C. Kiemle; G. Poberaj; M. Wirth

2005-01-01

181

Water vapor heterogeneity related to tropopause folds over the North Atlantic revealed by airborne water vapor differential absorption lidar  

Microsoft Academic Search

Airborne differential absorption lidar (DIAL) measurements of tropospheric water vapor and aerosol\\/clouds are presented from transfers across the North Atlantic on 13–15 May and 16–18 June 2002. The intense dynamical activity over the Atlantic is reflected in complex structures like deep tropopause folds, extended dry layers, and tilted aerosol filaments. Intrusions with H2O mixing ratios below 0.03 g kg?1 regularly

H. Flentje; A. Dörnbrack; G. Ehret; A. Fix; C. Kiemle; G. Poberaj; M. Wirth

2005-01-01

182

Carrying Capacity  

NSDL National Science Digital Library

This lesson helps students understand the notion of carrying capacity as it relates to ecosystems by considering an image of a bucket filled with water, and then filled with an "ecosystem." Students are asked to consider the factors on which carrying capacity is determined, and that a ecosystem's carrying capacity can change when certain variables are also changed.

183

[Estimation and allocation of water environmental capacity in nonpoint source polluted river].  

PubMed

Based on the investigation of the application and emission quantities (QAE) of total nitrogen (TN) and total phosphorus (TP) for nonpoint sources in river catchment' s area, included fertilizer applications, livestock and living pollutants emissions, the quantities of TN and TP entered the river were computed by means of export coefficient model in Changle River, southeast China. Self-purification capacities of TN and TP in the reach were also estimated in terms of input-output balance analysis method. According to the provisions of water function planning in the river, the water environment residual capacity (WERC) or the demand for reducing the application and emission (DRAE) of nitrogen and phosphorus in the corresponding catchment were monthly estimated, and WERC and DRAE were respectively allocated among the pollution sources. Results indicated that about 28.8% of TN loads and 51.2% of TP loads could be self-purified respectively in the reach, i. e., purification of 775.9 t a(-1) for TN and 30.9 t a(-1) for TP. Seasonal variations of the self-purification for the pollutants not only resulted from riverine hydrological and ecological conditions, but also affected by the pollution loading. According to the demand of the water quality protection in the reach, about 1581.0 t a(-1) QAE of TN had to reduce in Changle catchment. The maximum demand for the reducing QAE of TN was the fertilizer application (1047.4 t a(-1)), and the highest ratio for the reducing QAE of TN was livestock-poultry breeding (32.4%). There was about 2335.7 t a(-1) WERC for TP in the reach. The largest DRAE of nitrogen was during mid-water season and the least WERC of TP was during higher-water season. PMID:17891945

Chen, Ding-jiang; Lü, Jun; Jin, Shu-quan; Shen, Ye-na

2007-07-01

184

Measurement of Rn-222 in water by absorption in polycarbonates and liquid scintillation counting  

NASA Astrophysics Data System (ADS)

This work presents a new technique for measurement of activity concentrations of Rn-222 in water which is based on liquid scintillation counting (LSC) of polycarbonates exposed in the water. The polycarbonate material has high absorption ability to radon and when exposed in a radon-containing environment (air or water), it absorbs and concentrates radon in its volume. This property of the polycarbonate material is used for sampling 222Rn from the water. The main new element in this work is that it proposes the LSC technique for measurement of the radiation, emitted from the polycarbonate material. This radiation is due to the decay of the absorbed 222Rn and its progeny. Experimental results of LSC of polycarbonate granules and thin foils exposed in water with different activity concentrations of Rn-222 are presented. In all cases a very good linear correlation between the LS counting rate and the activity concentration of the water is found. The LSC of polycarbonates shows similar or even higher sensitivity in comparison to that of LSC of water. The estimated radon-in-water minimal detectable activity concentrations of the proposed method are similar or lower than those of the LSC and lower than those obtained by gamma spectrometry. The proposed method is simple, robust, inexpensive and avoids the need of taking water samples for laboratory analysis. It facilitates studies of the spatial distribution of 222Rn in water basins by exposure of polycarbonate specimens at different spots or depths and subsequent liquid scintillation counting.

Mitev, K.; Dimitrova, I.; Zhivkova, V.; Georgiev, S.; Gerganov, G.; Pressyanov, D.; Boshkova, T.

2012-06-01

185

Preliminary measurements with an automated compact differential absorption lidar for the profiling of water vapor.  

PubMed

The design and preliminary tests of an automated differential absorption lidar (DIAL) that profiles water vapor in the lower troposphere are presented. The instrument, named CODI (for compact DIAL), has been developed to be eye safe, low cost, weatherproof, and portable. The lidar design and its unattended operation are described. Nighttime intercomparisons with in situ sensors and a radiosonde are shown. Desired improvements to the lidar, including a more powerful laser, are also discussed. PMID:15176200

Machol, Janet L; Ayers, Tom; Schwenz, Karl T; Koenig, Keith W; Hardesty, R Michael; Senff, Christoph J; Krainak, Michael A; Abshire, James B; Bravo, Hector E; Sandberg, Scott P

2004-05-20

186

Bradykinin B2 receptor antagonist increases chloride and water absorption in rat medullary collecting duct.  

PubMed

This study tested the hypothesis that intrarenal kinins play a regulatory role in electrolyte excretion by altering Cl- absorption in the collecting duct. We measured Cl- and insulin concentrations in tubular fluid samples obtained from medullary collecting ducts (MCD) of Dahl/Rapp salt-resistant (SR/ Jr) rats by microcatheterization of ducts of Bellini before and after treatment with the bradykinin receptor antagonist HOE-140. Tubular fluid was obtained from paired terminal inner medullary (t-IMCD) and outer medullary (OMCD) collecting duct sites of the left kidney. HOE-140 (n = 7) or vehicle (n = 5) was infused intravenously, and the collections were repeated. HOE-140 did not alter glomerular filtration rate but decreased urine flow rate (P < 0.05) and absolute and fractional Cl- excretion (P < 0.01). HOE-140 did not alter the fraction of filtered Cl- delivered (FDCl) to the OMCD but decreased FDCl to the t-IMCD from 2.3 +/- 0.3 to 1.3 +/- 0.3% (P < 0.05). The fraction of filtered Cl- absorbed per millimeter between the collection sites was increased from 0.2 +/- 0.1 to 0.6 +/- 0.1% (P < 0.05). Fractional absorption of water along the MCD was also increased (P < 0.05). No changes in excretory function or tubular Cl- or water absorption were observed in vehicle-treated rats. These studies show that kinin B2 receptor blockade enhances Cl- and water absorption in the MCD, a finding that supports a role of renal kinins in the regulation of NaCl and water excretion. PMID:8770134

Mukai, H; Fitzgibbon, W R; Bozeman, G; Margolius, H S; Ploth, D W

1996-08-01

187

Comparative simulation and investigation of ammonia-water: absorption cycles for heat pump applications  

Microsoft Academic Search

Several recent programs in absorption research have focused on technology for domestic heating and cooling utilizing natural gas. In residential and small commercial size applications, ammonia-water cycles offer the possibility of a gas-fired heat pump for both winter heating and summer cooling, at better year-round COPS than currently available by various alternatives. Several cycles have been considered for this purpose,

M Engler; G Grossman; H.-M Hellmann

1997-01-01

188

Airborne remote sensing of tropospheric water vapor with a near-infrared differential absorption lidar system.  

PubMed

A near-infrared airborne differential absorption lidar (DIAL) system has become operational. Horizontal and vertical water vapor profiles of the troposphere during summer (nighttime) conditions extending from the top of the planetary boundary layer (PBL) up to near the tropopause are investigated. These measurements have been performed in Southern Bavaria, Germany. The system design, the frequency control units, and an estimation of the laser line profile of the narrow-band dye laser are discussed. Effective absorption cross sections in terms of altitude are calculated. Statistical and systematic errors of the water vapor measurements are evaluated as a function of altitude. The effect of a systematic range-dependent error caused by molecular absorption is investigated by comparing the DIAL data with in situ measurements. Typical horizontal resolutions range from 4 km in the lower troposphere to 11 km in the upper troposphere, with vertical resolutions varying from 0.3 to 1 km, respectively. The lower limit of the sensitivity of the water vapor mixing ratio is calculated to be 0.01 g/kg. The total errors of these measurements range between 8% and 25%. A sine-shaped wave structure with a wavelength of 14 km and an amplitude of 20% of its mean value, detected in the lower troposphere, indicates an atmospheric gravity wave field. PMID:20830116

Ehret, G; Kiemle, C; Renger, W; Simmet, G

1993-08-20

189

Investigation of the impact of water absorption on retinal OCT imaging in the 1060 nm range  

PubMed Central

Recently, the wavelength range around 1060 nm has become attractive for retinal imaging with optical coherence tomography (OCT), promising deep penetration into the retina and the choroid. The adjacent water absorption bands limit the useful bandwidth of broadband light sources, but until now, the actual limitation has not been quantified in detail. We have numerically investigated the impact of water absorption on the axial resolution and signal amplitude for a wide range of light source bandwidths and center wavelengths. Furthermore, we have calculated the sensitivity penalty for maintaining the optimal resolution by spectral shaping. As our results show, with currently available semiconductor-based light sources with up to 100–120 nm bandwidth centered close to 1060 nm, the resolution degradation caused by the water absorption spectrum is smaller than 10%, and it can be compensated by spectral shaping with negligible sensitivity penalty. With increasing bandwidth, the resolution degradation and signal attenuation become stronger, and the optimal operating point shifts towards shorter wavelengths. These relationships are important to take into account for the development of new broadband light sources for OCT. PMID:22808433

Marschall, Sebastian; Pedersen, Christian; Andersen, Peter E.

2012-01-01

190

Differential absorption and Raman lidar for water vapor profile measurements - A review  

NASA Technical Reports Server (NTRS)

Differential absorption lidar and Raman lidar have been applied to the range-resolved measurements of water vapor density for more than 20 years. Results have been obtained using both lidar techniques that have led to improved understanding of water vapor distributions in the atmosphere. This paper reviews the theory of the measurements, including the sources of systematic and random error; the progress in lidar technology and techniques during that period, including a brief look at some of the lidar systems in development or proposed; and the steps being taken to improve such lidar systems.

Grant, William B.

1991-01-01

191

Automated atomic absorption spectrometric determination of total arsenic in water and streambed materials  

USGS Publications Warehouse

An automated method to determine both inorganic and organic forms of arsenic In water, water-suspended mixtures, and streambed materials Is described. Organic arsenic-containing compounds are decomposed by either ultraviolet radiation or by suHurlc acid-potassium persulfate digestion. The arsenic liberated, with Inorganic arsenic originally present, is reduced to arsine with sodium borohydrlde. The arable Is stripped from the solution with the aid of nitrogen and Is then decomposed In a tube furnace heated to 800 ??C which Is placed in the optical path of an atomic absorption spectrometer. Thirty samples per hour can be analyzed to levels of 1 ??g arsenic per liter.

Fishman, M.

1977-01-01

192

Water vapor absorption spectra of the upper atmosphere /45-185 per cm/  

NASA Technical Reports Server (NTRS)

The far IR nighttime absorption spectrum of the earth's atmosphere above 14 km is determined from observations of the bright moon. The spectra were obtained using a Michelson interferometer attached to a 30-cm telescope aboard a high-altitude jet aircraft. Comparison with a single-layer model atmosphere implies a vertical column of 3.4 plus or minus 0.4 microns of precipitable water on 30 August 1971 and 2.4 plus or minus 0.3 microns of precipitable water on 6 January 1972.-

Augason, G. C.; Mord, A. J.; Witteborn, F. C.; Erickson, E. F.; Swift, C. D.; Caroff, L. J.; Kunz, L. W.

1975-01-01

193

Water vapor absorption spectra of the upper atmosphere (45-185 cm(-1)).  

PubMed

The far ir nighttime absorption spectrum of the earth's atmosphere above 14 km is determined from observations of the bright moon. The spectra were obtained using a Michelson interferometer attached to a 30-cm telescope aboard a high-altitude jet aircraft. Comparison with a single-layer model atmosphere implies a vertical column of 3.4 +/- 0.4 mum of percipitable water on 30 August 1971 and 2.4 +/- 0.3 mum of precipitable water on 6 January 1972. PMID:20154976

Augason, G C; Mord, A J; Witteborn, F C; Erickson, E F; Swift, C D; Caroff, L J; Kunz, L W

1975-09-01

194

In-Line Capacitance Sensor for Real-Time Water Absorption Measurements  

NASA Technical Reports Server (NTRS)

A capacitance/dielectric sensor was designed, constructed, and used to measure in real time the in-situ water concentration in a desiccant water bed. Measurements were carried out with two experimental setups: (1) passing nitrogen through a humidity generator and allowing the gas stream to become saturated at a measured temperature and pressure, and (2) injecting water via a syringe pump into a nitrogen stream. Both water vapor generating devices were attached to a downstream vertically-mounted water capture bed filled with 19.5 g of Moisture Gone desiccant. The sensor consisted of two electrodes: (1) a 1/8" dia stainless steel rod placed in the middle of the bed and (2) the outer shell of the stainless steel bed concentric with the rod. All phases of the water capture process (background, heating, absorption, desorption, and cooling) were monitored with capacitance. The measured capacitance was found to vary linearly with the water content in the bed at frequencies above 100 kHz indicating dipolar motion dominated the signal; below this frequency, ionic motion caused nonlinearities in the water concentration/capacitance relationship. The desiccant exhibited a dielectric relaxation whose activation energy was lowered upon addition of water indicating either a less hindered rotational motion or crystal reorientation.

Nurge, Mark A.; Perusich, Stephen A.

2010-01-01

195

Protein-water network dynamics during metalloenzyme hydrolysis observed by kinetic THz absorption (KITA)  

NASA Astrophysics Data System (ADS)

For long, the contribution of water network motions to enzymatic reactions was enigmatic due to the complexity of biological systems and to experimental limitations. Thanks to the development of new powerful THz emitters and detectors in the last decades, it is now possible to probe dynamics on the timescale of the fast hydrogen bond rearrangements during biochemical reactions. For this purpose, we developed a kinetic terahertz absorption (KITA) spectrometer which combines the strength of THz radiation (~1012 Hz = 1 ps) to directly probe collective picosecond protein-water dynamics with the fast mixing properties of a stopped-flow apparatus which initializes a biochemical reaction within milliseconds. With KITA, we analyzed the collective water dynamics during substrate hydrolyses by a human matrix-metalloproteinase. In addition, we studied the reorganization and electrostatic changes at the catalytic zinc-ion from the enzyme active site and performed molecular dynamics simulations of the enzyme-substrate-water system. Our results revealed a systematic gradient of water network motions: From the active site to the bulk water hydrogen bond dynamics increased from 7 ps (active site) to 1ps (bulk water) prior to substrate binding and hydrolysis. The approaching substrate perturbs the dynamic water gradient resulting in an overshoot of KITA signal which then relaxes back during onset of substrate hydrolyses. Our findings suggest that collective water dynamics may contribute to effective substrate binding to enzyme active sites and could be induced by the charge of the catalytic zinc-ion residing at the active site.

Born, Benjamin; Heyden, Matthias; Grossman, Moran; Sagi, Irit; Havenith, Martina

2013-02-01

196

Structural Change of the Mixtures of Ionic Liquid and Water Studied by Infrared Absorption Spectroscopy  

NASA Astrophysics Data System (ADS)

Infrared absorption spectra of the mixtures of ionic liquid and water (1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM]BF4) with varying concentrations were obtained by Attenuated Total Reflection (ATR) method. Investigation of the spectra in the OH-stretch vibration range indicated the structural change of the water with the change in the concentration. At very low concentration of water, two peaks around 3600cm-1 were assigned to the monomeric form of water molecules weakly hydrogen bonded to the BF4^- anions. With the increase in the water concentration, the broad feature at ˜3460cm-1 corresponding to the bulk water took over the above monomeric peaks, which gradually redshifted with the increased water concentration. In the range from 2800 to 3200cm-1 for the various CH-stretch vibration modes in the cation, the peaks in this ranged blueshifted with the increase in the water concentration. This blueshift was as much as ˜7cm-1 for the CH3 vibration modes of butyl chain while it hardly changed for the modes for the CH attached to the imidazolium core, suggesting varying degree of interactions between the carbon-bonded hydrogen and the water molecules.

Kim, Doseok; Jeon, Yoonnam; Sung, Jaeho; Ouchi, Yukio

2006-03-01

197

Strong water absorption in the dayside emission spectrum of the planet HD 189733b.  

PubMed

Recent observations of the extrasolar planet HD 189733b did not reveal the presence of water in the emission spectrum of the planet. Yet models of such 'hot-Jupiter' planets predict an abundance of atmospheric water vapour. Validating and constraining these models is crucial to understanding the physics and chemistry of planetary atmospheres in extreme environments. Indications of the presence of water in the atmosphere of HD 189733b have recently been found in transmission spectra, where the planet's atmosphere selectively absorbs the light of the parent star, and in broadband photometry. Here we report the detection of strong water absorption in a high-signal-to-noise, mid-infrared emission spectrum of the planet itself. We find both a strong downturn in the flux ratio below 10 microm and discrete spectral features that are characteristic of strong absorption by water vapour. The differences between these and previous observations are significant and admit the possibility that predicted planetary-scale dynamical weather structures may alter the emission spectrum over time. Models that match the observed spectrum and the broadband photometry suggest that heat redistribution from the dayside to the nightside is weak. Reconciling this with the high nightside temperature will require a better understanding of atmospheric circulation or possible additional energy sources. PMID:19079054

Grillmair, Carl J; Burrows, Adam; Charbonneau, David; Armus, Lee; Stauffer, John; Meadows, Victoria; van Cleve, Jeffrey; von Braun, Kaspar; Levine, Deborah

2008-12-11

198

Growth performance, metabolic and endocrine traits, and absorptive capacity in neonatal calves fed either colostrum or milk replacer at two levels.  

PubMed

Colostrum (CO) contains high amounts, whereas whole milk and milk replacer (MR) contain small amounts, of bioactive and growth-promoting substances, such as IGF-I. An experiment was designed to study the effects of feeding CO or MR on the first 3 d to neonatal calves, followed by whole milk up to d 7, at low and high density. Intestinal absorptive capacity, plasma metabolite and hormone concentrations, and growth performance were measured during the 1st wk of life. Body weight increased (P < .05) similarly in calves fed low or high amounts of CO but did not rise in MR-fed calves. Loose feces were more frequent (P < .05) and absorption of xylose on d 5 was lower (P < .01) in MR- than in CO-fed calves, but there were no effects of feeding density within CO-fed or within MR-fed groups. However, high feeding density within CO-fed groups enhanced (P < .05) total protein, globulin, triglyceride, cholesterol, and insulin concentrations, whereas in the initially high and low MR-fed groups only plasma glucose and insulin after the first meal and plasma NEFA on d 2 were modified (P < .05) by different feeding density. Thus, feeding different amounts of CO partly influenced protein and fat metabolism in calves during the 1st wk of life, but it did not measurably affect intestinal function. However, feeding different amounts of MR, in the absence of CO, barely affected metabolic and endocrine traits and absorptive capacity. Thus, high density CO feeding, and therefore a high supply of nutrients, together with greater amounts of bioactive and growth-promoting substances influenced neonatal metabolism and growth more than a high density of MR feeding containing only small amounts of bioactive and growth-promoting substances. Factors in addition to nutrient density seem to be important for the development of neonatal calves. PMID:10764068

Kühne, S; Hammon, H M; Bruckmaier, R M; Morel, C; Zbinden, Y; Blum, J W

2000-03-01

199

Diesel driven low capacity heat pump for heating and hot water production  

NASA Astrophysics Data System (ADS)

Heat pumps that reduce primary energy consumption for heating needs when they are driven by an internal combustion motor were studied. The heat produced as well from the heat pump as from the combustion in the diesel motor was used for home heating and hot water preparation. The objective was a 25kW capacity for a one familiy house. Material used should be standard, so a special design diesel motor or heat pump was not considered. An air/water cooled type diesel motor was coupled to a 12kW capacity heat pump for an outdoor temperature of 3 C using R12 freon as refrigerant. Description of all elements is given. Tests were in the laboratory and in a one family house. The expected efficiency factor of 1.34 could not be confirmed and an average annual value of only 1.05 is assumed. The diesel driven heat pump can not produce the energy savings hoped for.

Hoefler, P.

1982-08-01

200

ISO-SWS observations of pure rotational water absorption lines toward Orion-IRc2  

E-print Network

First detections of thermal water vapor absorption lines have been made toward Orion IRc2 using the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). Grating spectra covering wavelengths 25-45 micron yield 19 pure rotational lines, originating from energy levels 200-750 K above ground. Fabry-Perot spectra of 5 transitions resolve the line profiles and reveal the water gas kinematics. The fact that all lines are seen in absorption is in striking contrast with data from the ISO Long Wavelength Spectrometer (LWS), where the water lines appear in emission. At least one line displays a P-Cygni type profile, which suggests that the water is located in an expanding shell centered on or near IRc2. The expansion velocity is 18 km per second, in agreement with the value inferred from water maser observations by Genzel et al. (1981). Because the continuum is intense and likely formed in or near the water-containing gas, the excitation of the observed transitions is dominated by radiative processes. A simple, generalised curve-of-growth method is presented and used to analyze the data. A mean excitation temperature of 72 K and a total water column density of 1.5e18 molecules per cm squared are inferred, each with an estimated maximum uncertainty of 20%. Combined with the molecular hydrogen column density derived from ISO observations of the pure rotational lines, and an assumed temperature of 200-350 K, the inferred water abundance is 2e-4 to 5e-4 in the warm shocked gas. This abundance is similar to that found recently by Harwit et al. (1998) toward Orion using data from the LWS, but higher than that found for most other shocked regions by, for example, Liseau et al. (1996).

C. M. Wright; E. F. van Dishoeck; J. H. Black; H. Feuchtgruber; J. Cernicharo; E. Gonzalez-Alfonso; Th. de Graauw

2000-04-07

201

Airborne differential absorption lidar system for measurements of atmospheric water vapor and aerosols.  

PubMed

An airborne differential absorption lidar (DIAL) system has been developed at the NASA Langley Research Center for remote measurements of atmospheric water vapor (H(2)O) and aerosols. A solid-state alexandrite laser with a 1-pm linewidth and > 99.85% spectral purity was used as the on-line transmitter. Solid-state avalanche photodiode detector technology has replaced photomultiplier tubes in the receiver system, providing an average increase by a factor of 1.5-2.5 in the signal-to-noise ratio of the H(2)O measurement. By incorporating advanced diagnostic and data-acquisition instrumentation into other subsystems, we achieved additional improvements in system operational reliability and measurement accuracy. Laboratory spectroscopic measurements of H(2)O absorption-line parameters were perfo med to reduce the uncertainties in our knowledge of the absorption cross sections. Line-center H(2)O absorption cross sections were determined, with errors of 3-6%, for more than 120 lines in the 720-nm region. Flight tests of the system were conducted during 1989-1991 on the NASA Wallops Flight Facility Electra aircraft, and extensive intercomparison measurements were performed with dew-point hygrometers and H(2)O radiosondes. The H(2)O distributions measured with the DIAL system differed by ? 10% from the profiles determined with the in situ probes in a variety of atmospheric conditions. PMID:20941181

Higdon, N S; Browell, E V; Ponsardin, P; Grossmann, B E; Butler, C F; Chyba, T H; Mayo, M N; Allen, R J; Heuser, A W; Grant, W B; Ismail, S; Mayor, S D; Carter, A F

1994-09-20

202

A comparison of methods for the measurement of the absorption coefficient in natural waters  

NASA Technical Reports Server (NTRS)

In the spring of 1992 an optical closure experiment was conducted at Lake Pend Orielle, Idaho. A primary objective of the experiment was to compare techniques for the measurement of the spectral absorption coefficent and other inherent optical properties of natural waters. Daily averages of absorption coefficents measured using six methods are compared at wavelengths of 456, 488, and 532 nm. Overall agreement was within 40% at 456 nm and improved with increasing wavelength to 25% at 532 nm. These absorption measurements were distributed over the final 9 days of the experiement, when bio-optical conditions in Lake Pend Oreille (as indexed by the beam attenuation coefficent c(sub p)(660) and chlorophyll a fluorescence profiles) were representative of those observed throughout the experiment. However, profiles of stimulated chlorophyll a fluorescence and beam transmission showed that bio-optical properties in the lake varied strongly on all time and space scales. Therefore environmental variabilty contributed significantly to deviations between daily mean absorption coefficients measured using the different techniques.

Pegau, W. Scott; Cleveland, Joan S.; Doss, W.; Kennedy, C. Dan; Maffione, Robert A.; Mueller, James L.; Stone, R.; Trees, Charles C.; Weidemann, Alan D.; Wells, Willard H.

1995-01-01

203

A study of water vapor absorption at CO2 laser frequencies using a differential spectrophone and white cell  

Microsoft Academic Search

Water vapor absorption at CO2 laser frequencies has been studied using a differential spectrophone and a long path multiple traversal cell. The results of these measurements have been analyzed in terms of the Lorentz line shape and the far wing model for continuum absorption in the 9-10 micrometers wavelength region. An electronically stabilized, grating tunable cw CO2 laser with a

J. C. Peterson

1978-01-01

204

Arsenic exposure from drinking water, arsenic methylation capacity, and carotid intima-media thickness in Bangladesh.  

PubMed

We conducted a cross-sectional study to evaluate the interrelationships between past arsenic exposure, biomarkers specific for susceptibility to arsenic exposure, and carotid intima-media thickness (cIMT) in 959 subjects from the Health Effects of Arsenic Longitudinal Study in Bangladesh. We measured cIMT levels on average 7.2 years after baseline during 2010-2011. Arsenic exposure was measured in well water at baseline and in urine samples collected at baseline and during follow-up. Every 1-standard-deviation increase in urinary arsenic (357.9 µg/g creatinine) and well-water arsenic (102.0 µg/L) concentration was related to a 11.7-µm (95% confidence interval (CI): 1.8, 21.6) and 5.1-µm (95% CI: -0.2, 10.3) increase in cIMT, respectively. For every 10% increase in monomethylarsonic acid (MMA) percentage, there was an increase of 12.1 µm (95% CI: 0.4, 23.8) in cIMT. Among participants with a higher urinary MMA percentage, a higher ratio of urinary MMA to inorganic arsenic, and a lower ratio of dimethylarsinic acid to MMA, the association between well-water arsenic and cIMT was stronger. The findings indicate an effect of past long-term arsenic exposure on cIMT, which may be potentiated by suboptimal or incomplete arsenic methylation capacity. Future prospective studies are needed to confirm the association between arsenic methylation capacity and atherosclerosis-related outcomes. PMID:23788675

Chen, Yu; Wu, Fen; Graziano, Joseph H; Parvez, Faruque; Liu, Mengling; Paul, Rina Rani; Shaheen, Ishrat; Sarwar, Golam; Ahmed, Alauddin; Islam, Tariqul; Slavkovich, Vesna; Rundek, Tatjana; Demmer, Ryan T; Desvarieux, Moise; Ahsan, Habibul

2013-08-01

205

Chiral monolithic absorbent constructed by optically active helical-substituted polyacetylene and graphene oxide: preparation and chiral absorption capacity.  

PubMed

Chiral monolithic absorbent is successfully constructed for the first time by using optically active helical-substituted polyacetylene and graphene oxide (GO). The preparative strategy is facile and straightforward, in which chiral-substituted acetylene monomer (Ma), cross-linker (Mb), and alkynylated GO (Mc) undergo copolymerization to form the desired monolithic absorbent in quantitative yield. The resulting monoliths are characterized by circular dichroism, UV-vis absorption, scanning electron microscopy (SEM), FT-IR, Raman, energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), XPS, and thermogravimetric analysis (TGA) techniques. The polymer chains derived from Ma form chiral helical structures and thus provide optical activity to the monoliths, while GO sheets contribute to the formation of porous structures. The porous structure enables the monolithic absorbents to demonstrate a large swelling ratio in organic solvents, and more remarkably, the helical polymer chains provide optical activity and further enantio-differentiating absorption ability. The present study establishes an efficient and versatile methodology for preparing novel functional materials, in particular monolithic chiral materials based on substituted polyacetylene and GO. PMID:25490977

Li, Weifei; Wang, Bo; Yang, Wantai; Deng, Jianping

2015-02-01

206

Atmospheric water vapor differential absorption measurements on vertical paths with a CO2 lidar.  

PubMed

Ground based vertical path differential absorption measurements were obtained up to a height of 1.5 km with a CO2 lidar transmitting alternatively on the R(20) (10.247-microm) and R(18) (10.260-microm) lines during daylight in conditions of both strong and weak temperature inversions. The differential absorption between these lines for typical middle latitude lower atmosphere water vapor concentrations appears to be well suited to this type of measurement as the power loss on the more absorbed backscattered line [R(20)] is not too great as to unduly restrict the operating range, while the power differential is still sufficiently large to be readily measureable. In one set of measurements a strong temperature inversion at a height of 1 km resulted in a rapid vertical lapse in aerosol concentration with a consequent loss of SNR on the returns and severe distortion to the differential absorption profiles at this level. Water vapor profiles were derived from all measurements except in the region of the strong temperature inversion where the atmospheric backscattering cross section decayed rapidly. Reasonable results were obtained through the weak inversion region. The measurement capability of the lidar was found to be restricted by the length of the laser pulse tail and an inadequate signal-to-noise performance in regions of strong temperature inversions due to the associated decreases in aerosol concentration. PMID:18196122

Baker, P W

1983-08-01

207

Temperature sensitivity of differential absorption lidar measurements of water vapor in the 720-nm region.  

PubMed

Recently measured properties of water vapor (H(2)O) absorption lines have been used in calculations to evaluate the temperature sensitivity of differential absorption lidar (DIAL) H(2)O measurements. This paper estimates the temperature sensitivity of H(2)O lines in the 717-733-nm region for both H(2)O mixing ratio and number density measurements, and discusses the influence of the H(2)O line ground state energies E'', the H(2)O absorption linewidths, the linewidth temperature dependence parameter, and the atmospheric temperature and pressure variations with altitude and location on the temperature sensitivity calculations. Line parameters and temperature sensitivity calculations for sixty-seven H(2)O lines in the 720-nm band are given which can be directly used in field experiments. Water vapor lines with E'' values in the 100-300-cm(-1) range were found to be optimum for DIAL measurements of H(2)O number densities, while E'' values in the 250-500-cm(-1) range were found to be optimum for H(2)O mixing ratio measurements. PMID:20700314

Browell, E V; Ismail, S; Grossmann, B E

1991-04-20

208

WATER ABSORPTION FROM GAS VERY NEAR THE MASSIVE PROTOSTAR AFGL 2136 IRS 1  

SciTech Connect

We present ground-based observations of the ?{sub 1} and ?{sub 3} fundamental bands of H{sub 2}O toward the massive protostar AFGL 2136 IRS 1, identifying absorption features due to 47 different ro-vibrational transitions between 2.468 ?m and 2.561 ?m. Analysis of these features indicates the absorption arises in warm (T = 506 ± 25 K), very dense (n(H{sub 2}) > 5 × 10{sup 9} cm{sup –3}) gas, suggesting an origin close to the central protostar. The total column density of warm water is estimated to be N(H{sub 2}O) = (1.02 ± 0.02) × 10{sup 19} cm{sup –2}, giving a relative abundance of N(H{sub 2}O)/N(H{sub 2}) ? 10{sup –4}. Our study represents the first extensive use of water vapor absorption lines in the near infrared, and demonstrates the utility of such observations in deriving physical parameters.

Indriolo, Nick; Neufeld, D. A. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Seifahrt, A. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Richter, M. J. [Department of Physics, University of California Davis, Davis, CA 95616 (United States)

2013-10-10

209

Interfacial water. The structure of interfacial water on gold electrodes studied by x-ray absorption spectroscopy.  

PubMed

The molecular structure of the electrical double layer determines the chemistry in all electrochemical processes. Using x-ray absorption spectroscopy (XAS), we probed the structure of water near gold electrodes and its bias dependence. Electron yield XAS detected at the gold electrode revealed that the interfacial water molecules have a different structure from those in the bulk. First principles calculations revealed that ~50% of the molecules lie flat on the surface with saturated hydrogen bonds and another substantial fraction with broken hydrogen bonds that do not contribute to the XAS spectrum because their core-excited states are delocalized by coupling with the gold substrate. At negative bias, the population of flat-lying molecules with broken hydrogen bonds increases, producing a spectrum similar to that of bulk water. PMID:25342657

Velasco-Velez, Juan-Jesus; Wu, Cheng Hao; Pascal, Tod A; Wan, Liwen F; Guo, Jinghua; Prendergast, David; Salmeron, Miquel

2014-11-14

210

Preliminary Testing of a Water-Vapor Differential Absorption LIDAR (DIAL) Using a Widely Tunable Amplified Diode Laser Source  

Microsoft Academic Search

Water vapor plays an enormous role in Earth's atmospheric dynamics through cloud formation, precipitation, and interactions with electromagnetic radiation, especially its absorption of longwave infrared radiation. Detailed data of water vapor distribution and flux and related feedback mechanisms are required to better understand and predict local weather, global climate, and the water cycle. One method of obtaining this data in

Michael D. Obland; Kevin S. Repasky; Joseph A. Shaw; John L. Carlsten

2006-01-01

211

Integrated modelling to assess long-term water supply capacity of a meso-scale Mediterranean catchment.  

PubMed

Assessing water supply capacity is crucial to meet stakeholders' needs, notably in the Mediterranean region. This region has been identified as a climate change hot spot, and as a region where water demand is continuously increasing due to population growth and the expansion of irrigated areas. The Hérault River catchment (2500 km(2), France) is a typical example and a negative trend in discharge has been observed since the 1960s. In this context, local stakeholders need first to understand the processes controlling the evolution of water resources and demands in the past to latter evaluate future water supply capacity and anticipate the tensions users could be confronted to in the future. A modelling framework is proposed at a 10-day time step to assess whether water resources have been able to meet water demands over the last 50 years. Water supply was evaluated using hydrological modelling and a dam management model. Water demand dynamics were estimated for the domestic and agricultural sectors. A water supply capacity index is computed to assess the extent and the frequency to which water demand has been satisfied at the sub-basin scale. Simulated runoff dynamics were in good agreement with observations over the calibration and validation periods. Domestic water demand has increased considerably since the 1980s and is characterized by a seasonal peak in summer. Agricultural demand has increased in the downstream sub-basins and decreased upstream where irrigated areas have decreased. As a result, although most water demands were satisfied between 1961 and 1980, irrigation requirements in summer have sometimes not been satisfied since the 1980s. This work is the first step toward evaluating possible future changes in water allocation capacity in the catchment, using future climate change, dam management and water use scenarios. PMID:23756213

Collet, Lila; Ruelland, Denis; Borrell-Estupina, Valérie; Dezetter, Alain; Servat, Eric

2013-09-01

212

Investigation of the Influence of Cooling Water Inlet Temperature on Characteristics and Ammonia Charging Quantity of Ammonia-Water Absorption Refrigerator  

NASA Astrophysics Data System (ADS)

For purposes such as freezing and ice accumulation which require temperatures below 0 degrees, ammonia-water absorption refrigerator is being looked at once again. If used for these purpose, it is usually driven all through the year. In this case, cooling water inlet temperature which greatly influences absorption cycle changes very widely. So in such conditions, it is hoped to be driven high efficiently. And ammonia's charging quantity is required as small as possible on account of poisonous. But when it driven all through the year, ammonia charging quantity influences the efficiency greatly. So this research aims to clarify the ammonia charging quantity with which ammonia-water absorption refrigerator can be driven high efficiently. So static simulation model was made. By using this tool, we investigated the influence of cooling water inlet temperature on COP, solution concentration. As a result, minimum ammonia charging quantity with which ammonia water absorption refrigerator can be driven was obtained.

Takei, Toshitaka; Saito, Kiyoshi; Kawai, Sunao

213

Kenaf/recycled Jute Natural Fibers Unsaturated Polyester Composites: Water Absorption/dimensional Stability and Mechanical Properties  

NASA Astrophysics Data System (ADS)

Effects of water absorption on the flexural properties of kenaf-unsaturated polyester composites and kenaf/recycled jute-unsaturated polyester composites were investigated. In the hybrid composites, the total fiber content was fixed to 20 wt%. In this 20 wt%, the addition of jute fiber varied from 0 to 75%, with increment of 25%. The result demonstrates the water absorption and the thickness swelling increased with increase in immersion time. Effects of water absorption on flexural properties of kenaf fiber composites can be reduced significantly with incorporation of recycled jute in composites formulation. The process of absorption of water was found to approach Fickian diffusion behavior for both kenaf composites and hybrid composites.

Osman, Ekhlas A.; Vakhguelt, Anatoli; Sbarski, Igor; Mutasher, Saad A.

2012-03-01

214

Differential absorption and Raman lidar for water vapor profile measurements; A review  

SciTech Connect

Differential absorption lidar and Raman lidar have been applied to the range-resolved measurements of water vapor density for more than 20 years. During this period, there have been considerable advances in laser and lidar technology, as well as in the understanding of the factors required to optimize both lidar techniques for water vapor measurements. Results have been obtained using both lidar techniques that have led to improved understanding of water vapor distributions in the atmosphere. This paper reviews the theory of the measurements, including the sources of systematic and random error; the progress in lidar technology and techniques during that period, including a brief look at some of the lidar systems in development or proposed; and the steps being taken to improve such lidar systems.

Grant, W.B. (NASA/Langley Research Center, Atmospheric Sciences Div., MS 401A, Hampton, VA (US))

1991-01-01

215

Performance of Generator of Absorption Refrigerating Machine Powered by Hot Water  

NASA Astrophysics Data System (ADS)

For 70 kW generator of absorption refrigerating machine powered by the hot water, lifted liquid rate of the bubble lift pump has a maximum value at some vapor flow rate of refrigerant and hot water inlet temperature. This is in agreement with results of small size bubble lift pump. Maximum lifted liquid rate G0 is correlated by the equation G0 = 5, 000?1.5, where ? is the degree of submergence. In this case, diameter of pump tube was 41.6mm, and length of it were 1,300 and 1,500mm. The range of hot water inlet temperature was 78 - 100°C. Multitube heat flux of first generator is about two times that of second generator at the same superheat.

Kunugi, Yoshifumi; Usui, Sanpei; Ouchi, Tomihisa; Fukuda, Tamio

216

A high energy diode-pumped Cr:LiSAF laser for water vapor differential absorption lidar  

Microsoft Academic Search

Summary form only given. The near-IR absorption bands in the 810-830 nm and 930-950 nm range are well suited for remote measurements of water vapor with differential absorption lidar. A diode-pumped Cr:LiSAF laser which can be tuned over these bands has a great potential as a compact and efficient, narrow linewidth source for atmospheric water vapor DIAL. We present the

V. Fromzel; C. R. Prasad; C. Johnson; N. P. Barnes; G. H. Kim; R. D. Mead

1999-01-01

217

Chemical Characterization and Water Holding Capacity of Fibre-rich Feedstuffs Used for Pigs in Vietnam  

PubMed Central

During two years, four samples per year were collected in Vietnam from rice bran, cassava residue, brewer’s grain, tofu residue, soybean meal, coconut cake, sweet potato vines and water spinach for chemical analysis and assessment of water holding capacity (WHC). The selected feedstuffs represent fibre-rich plant sources and agro-industry co-products commonly used in pig feeding in Vietnam. The content (g/kg DM) of crude protein (CP), ether extract (EE) and non-starch polysaccharides (NSP) varied between feedstuffs and ranged from 21 to 506 for CP, from 14 to 118 for EE and from 197 to 572 for NSP. Cassava residue had a high starch content of 563 g/kg DM, while sweet potato vines, water spinach, coconut cake and soybean meal had a high content of sugars (63–71 g/kg DM). The content of individual neutral sugars varied between feed ingredients, with the highest content of arabinose, galactose and glucose in tofu residue, the highest content of xylose in brewer’s grain and the highest content of mannose in coconut cake. The content of uronic acid was high for cassava residue, tofu residue, sweet potato vines and water spinach (57–88 g/kg DM). The content of soluble non-cellulosic polysaccharides (S-NCP) was positively correlated (r2 = 0.82) to the WHC. The content (g/kg DM) of CP, NDF, neutral sugars, total NSP, total NCP, S-NCP and total dietary fibre in tofu residue, water spinach and coconut cake varied (p<0.05) between years. In conclusion, diet formulation to pigs can be improved if the variation in chemical composition of the fibre fraction and in WHC between potential feed ingredients is taken into account. PMID:25049638

Ngoc, T. T. B.; Len, N. T.; Lindberg, J. E.

2012-01-01

218

Theoretical aspects of surface-to-volume ratios and water-storage capacities of succulent shoots.  

PubMed

Surface-to-volume (S/V) ratios of drought-adapted plants affect transpiration, photosynthesis, and water-storage capacity. The S/V ratio of cladodes and flat leaves is S/V = 2/T, where T is thickness: even slight thickening greatly reduces S/V. During rain/drought cycles succulent stems swell and shrink without tearing by having flexible ribs, but ribs increase S/V above that of a smooth cylindrical stem with equal volume: the increased surface area is S(ribbed)/S(cylindrical) = N[x + (?/N)]/?(1 + x), where N is number of ribs and x is rib height relative to the radius of the inner stem. Numerous low ribs provide moderate expandability (storage volume) with little increase in S/V and are adaptive where droughts are short. Tall ribs provide greater expandability but greatly increase S/V and probably are adaptive only in mesic habitats. Having ?8-15 ribs, each about as tall as the inner stem radius, provides large storage capacity and intermediate increase in S/V. By increasing absolute size, S/V is reduced so greatly that even large ribs can have an S/V smaller than that of a narrow cylindrical or spherical stem with less volume. PMID:10947995

Mauseth, J D

2000-08-01

219

Probing the vibrational dynamics of proteins in liquid water by terahertz absorption spectroscopy  

NASA Astrophysics Data System (ADS)

Biomolecules solvated in their biologically milieu are expected to exhibit strong absorption in the terahertz range that contain information on their global and subglobal collective vibrational modes and global dynamical correlations among solvent water molecules and the protein. Measurements in this region, however, are challenging due to due to the strong absorption of water and often sever interference artifacts. In response, we have developed, with Virginia Diode Inc., a highly sensitive Vector Network Analyzer system for probing collective dynamics in aqueous solution. Using this we explore the complex dielectric response from 0.07 to 0.70 THz that directly probes such questions as the hydration level around proteins and the large scale vibrational modes of biological polymers. We make a direct comparison to the existing molecular dynamic simulations and normal mode calculations and investigate the dependence of the low frequency dynamics on protein concentration and solvent pH. Our measurements shed light on the macromolecular motions in a biologically relevant water environment.

Quang Vinh, Nguyen; Plaxco, Kevin W.; Allen, S. James

2010-03-01

220

High-resolution atmospheric water vapor measurements with a scanning differential absorption lidar  

NASA Astrophysics Data System (ADS)

The scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) is presented. The UHOH DIAL is equipped with an injection-seeded frequency-stabilized high-power Ti:sapphire laser operated at 818 nm with a repetition rate of 250 Hz. A scanning transceiver unit with a 80 cm primary mirror receives the atmospheric backscatter signals. The system is capable of water vapor measurements with temporal resolutions of a few seconds and a range resolution between 30 and 300 m at daytime. It allows to investigate surface-vegetation-atmosphere exchange processes with high resolution. In this paper, we present the design of the instrument and illustrate its performance with recent water vapor measurements taken in Stuttgart-Hohenheim and in the frame of the HD(CP)2 Observational Prototype Experiment (HOPE). HOPE was located near research center Jülich, in western Germany, in spring 2013 as part of the project "High Definition of Clouds and Precipitation for advancing Climate Prediction" (HD(CP)2). Scanning measurements reveal the 3-dimensional structures of the water vapor field. The influence of uncertainties within the calculation of the absorption cross-section at wavelengths around 818 nm for the WV retrieval is discussed. Radiosonde intercomparisons show a very small bias between the instruments of only (-0.04 ± 0.11) g m-3 or (-1.0 ± 2.3) % in the height range of 0.5 to 3 km.

Späth, F.; Behrendt, A.; Muppa, S. K.; Metzendorf, S.; Riede, A.; Wulfmeyer, V.

2014-11-01

221

Impact of cooking formulation on flavor and hydrophilic oxygen radical absorption capacity values of whole grain pigmented rice  

Technology Transfer Automated Retrieval System (TEKTRAN)

Whole grain rice is rich in healthful phenolic compounds that can impart flavors. Rice is prepared with water, salt, and/or oil. There is little opportunity to influence the flavor of plain rice during preparation. This research examines how cooking whole grain rice with salt, oil, or salt with o...

222

Absorption of crystalline water ice in the far infrared at different temperatures  

NASA Astrophysics Data System (ADS)

The optical properties of ice in the far infrared are important for models of protoplanetary and debris disks. In this report, we derive a new set of data for the absorption (represented by the imaginary part of the refractive index ?) of crystalline water ice in this spectral range. The study includes a detailed inspection of the temperature dependence, which has not been conducted in such detail before. We measured the transmission of three ice layers with different thicknesses at temperatures ? = 10...250 K and present data at wavelengths ? = 80...625 ?m. We found a change in the spectral dependence of ? at a wavelength of 175 ± 6 ?m. At shorter wavelengths, ? exhibits a constant flat slope and no significant temperature dependence. Long-ward of that wavelength, the slope gets steeper and has a clear, approximately linear temperature dependence. This change in behaviour is probably caused by a characteristic absorption band of water ice. The measured data were fitted by a power-law model that analytically describes the absorption behaviour at an arbitrary temperature. This model can readily be applied to any object of interest, for instance a protoplanetary or debris disk. To illustrate how the model works, we simulated the spectral energy distribution (SED) of the resolved, large debris disk around the nearby solar-type star HD 207129. Replacing our ice model by another, commonly used data set for water ice results in a different SED slope at longer wavelengths. This leads to changes in the characteristic model parameters of the disk, such as the inferred particle size distribution, and affects the interpretation of the underlying collisional physics of the disk.

Reinert, C.; Mutschke, H.; Krivov, A. V.; Löhne, T.; Mohr, P.

2015-01-01

223

A new device for acquiring ground truth on the absorption of light by turbid waters  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. A new device, called a Spectral Attenuation Board, has been designed and tested, which enables ERTS-1 sea truth collection teams to monitor the attenuation depths of three colors continuously, as the board is being towed behind a boat. The device consists of a 1.2 x 1.2 meter flat board held below the surface of the water at a fixed angle to the surface of the water. A camera mounted above the water takes photographs of the board. The resulting film image is analyzed by a micro-densitometer trace along the descending portion of the board. This yields information on the rate of attenuation of light penetrating the water column and the Secchi depth. Red and green stripes were painted on the white board to approximate band 4 and band 5 of the ERTS MSS so that information on the rate of light absorption by the water column of light in these regions of the visible spectrum could be concurrently measured. It was found that information from a red, green, and white stripe may serve to fingerprint the composition of the water mass. A number of these devices, when automated, could also be distributed over a large region to provide a cheap method of obtaining valuable satellite ground truth data at present time intervals.

Klemas, V. (principal investigator); Srna, R.; Treasure, W.

1974-01-01

224

Evidence for direct water absorption by shallow-rooted desert plants in desert-oasis ecotone, Northwest China  

NASA Astrophysics Data System (ADS)

Besides the absorption by roots from the soil substrate, it has long been known that plants exhibit alternative water-absorption strategies, particularly in drought-prone environments. For many tropical epiphytic orchids, air moisture can be absorbed directly by aerial roots. Some conifers are also found to utilize air moisture by foliar absorption during the summer fog season. However, few studies have been carried out on the atmospheric water vapor absorption by shallow-rooted desert plants. We conducted experiments in desert-oasis ecotone and investigated the effects of dew absorbed by three kinds of shallow-rooted seedlings on net photosynthesis rate, as well as on other water relations variables. Three kinds of typical shallow-rooted desert species (Bassia dasyphylla, Salsola collina and Corispermum declinatum) have been chosen and potted. Each species were subjected to contrasting watering regimes (normal and deficient) and different air moisture conditions (having dew and having no dew) for 10 weeks. Net photosynthesis rate was measured on six occasions during the study. Other water relations variables (midday shoot water potential, relative water content, stomatal conductance) were also measured. Under the dew conditions, average net photosynthesis rate, shoot water potential, leaf relative water content and stomatal conductance increased, with greater responses observed for plants subjected to a deficient watering regime than for well-watered plants. These results indicated dew occurred in arid region could be utilized through foliar absorption by some shallow-rooted plants, and for the shallow-rooted plants, the presence of dew could significantly relieve the deficit of water in water-stressed regime.

Fang, Jing

2014-05-01

225

The impact of regional water resources capacity building: Citations of the published proceedings of the annual WaterNet\\/WARFSA\\/GWP-SA symposia in Southern Africa, 2001 2005  

Microsoft Academic Search

This paper measures the scientific impact of two regional water resources capacity building programmes in Southern Africa: WaterNet and WARFSA. The articles emanating from the annual symposia organised jointly by both programmes during the period 2001 2005 and published in special issues of Physics and Chemistry of the Earth were analysed in terms of numbers and citations. The paper concludes

Pieter van der Zaag

2007-01-01

226

X-ray absorption signatures of the molecular environment in water and ice  

E-print Network

The x-ray absorption spectra of water and ice are calculated with a many-body approach for electron-hole excitations. The experimental features, including the small effects of temperature change in the liquid, are quantitatively reproduced from molecular configurations generated by ab-initio molecular dynamics. The spectral difference between the solid and the liquid is due to two major short range order effects. One, due to breaking of hydrogen bonds, enhances the pre-edge intensity in the liquid. The other, due to a non-bonded molecular fraction in the first coordination shell, affects the main spectral edge in the conversion of ice to water. This effect may not involve hydrogen bond breaking as shown by experiment in high-density amorphous ice.

Wei Chen; Xifan Wu; Roberto Car

2009-09-21

227

High-resolution spectroscopy of cool K and M stars through the telluric water vapor absorption band near 9360 A. 1: Methodology and first results  

Microsoft Academic Search

An observational program has been undertaken for the study of stellar spectra within telluric water vapor lines absorption region near 9360 A. This program has been developed in the future context of a European Space Agency's (ESAs) environment-dedicated experiment designed to probe atmospheric water vapor absorption with cool star spectrophotometry. With ground observations presented here, we determine absorption levels and

T. Widemann; J.-L. Bertaux; M. Querci; F. Querci

1994-01-01

228

Absorption spectra of liquid water and aqueous buffers between 0.3 and Department of Physics, University of California, Santa Barbara, California 93106  

E-print Network

Absorption spectra of liquid water and aqueous buffers between 0.3 and 3.72 THz Jing Xua Department-dependent terahertz absorption with attenuation lengths on the order of tens of micrometers. To access this spectral.5 THz, these studies provide a well- documented absorption spectrum for liquid water, at approxi- mately

Xu, Jing

229

Thermodynamic assessment of the effect of strongly swelling polymer hydrogels on the water retention capacity of model porous media  

NASA Astrophysics Data System (ADS)

The effect of different rates and fractions of strongly swelling polymer hydrogel (SSPH) based on radiation-grafted polyacrylamide on the water retention capacity and structural state of model porous media in the form of quartz sand fractions with different degrees of dispersion has been studied. The water retention curve (WRC) of sandy porous media obtained by the capillarimetric method has been used as a basic thermodynamic parameter. An original method has been proposed for the comparative study of the effect of SSPHs on the WRC based on the approximation of data by the nonlinear van Genuchten function followed by differential analysis. Equations are given for the calculation of capillary water capacity and structural curves of pore size distribution. SSPH concentrations in the range 0.05-0.2% of enclosing material weight reliably increase the water retention capacity of sandy fractions and the total, capillary, and field capacities (determined by the Voronin secant method) by 2-3 times; as well as the range of available water and the contents of fine macropores and mesopores. Factors limiting the swelling of SSPHs in model porous media have been revealed.

Sadovnikova, N. B.; Smagin, A. V.; Sidorova, M. A.

2014-04-01

230

Progress toward a water-vapor differential absorption lidar (DIAL) using a widely tunable amplified diode laser source  

Microsoft Academic Search

Water vapor is one of the most significant constituents of the atmosphere because of its role in cloud formation, precipitation, and interactions with electromagnetic radiation, especially its absorption of longwave infrared radiation. Some details of the role of water vapor and related feedback mechanisms in the Earth system need to be characterized better if local weather, global climate, and the

Michael D. Obland; Lei S. Meng; Kevin S. Repasky; Joseph A. Shaw; John L. Carlsten

2005-01-01

231

Differential Absorption Lidar (DIAL) Measurements of Atmospheric Water Vapor Utilizing Robotic Aircraft  

NASA Technical Reports Server (NTRS)

A new unpiloted air vehicle (UAV) based water vapor DIAL system will be described. This system is expected to offer lower operating costs, longer test duration and severe weather capabilities. A new high-efficiency, compact, light weight, diode-pumped, tunable Cr:LiSAF laser will be developed to meet the UAV payload weight and size limitations and its constraints in cooling capacity, physical size and payload. Similarly, a new receiver system using a single mirror telescope and an avalanche photo diode (APD) will be developed. Projected UAV parameters are expected to allow operation at altitudes up to 20 km, endurance of 24 hrs and speed of 400 km/hr. At these conditions measurements of water vapor at an uncertainty of 2-10% with a vertical resolution of 200 m and horizontal resolution of 10 km will be possible.

Hoang, Ngoc; DeYoung, Russell J.; Prasad, Coorg R.; Laufer, Gabriel

1998-01-01

232

Solar cooling with the absorption principle: first and Second Law analysis of an ammonia—water double-generator absorption chiller  

Microsoft Academic Search

This article deals with the modelling, thermodynamic simulation and Second Law analysis of an ammonia—water double-effect, double-generator absorption chiller. The analysis of the unit established a simulation thermodynamic model as well as the limits of the operating conditions. Computer simulation was carried out in order to determine its stream properties and the amount of heat and work exchanged with the

N. Ben Ezzine; M. Barhoumi; Kh. Mejbri; S. Chemkhi; A. Bellagi

2004-01-01

233

Study of Water Absorption in Raffia vinifera Fibres from Bandjoun, Cameroon  

PubMed Central

The study is focused on the water diffusion phenomenon through the Raffia vinifera fibre from the stem. The knowledge on the behavior of those fibres in presence of liquid during the realization of biocomposite, is necessary. The parameters like percentage of water gain at the point of saturation, modelling of the kinetic of water absorption, and the effective diffusion coefficient were the main objectives. Along a stem of raffia, twelve zones of sampling were defined. From Fick's 2nd law of diffusion, a new model was proposed and evaluated compared to four other models at a constant temperature of 23°C. From the proposed model, the effective diffusion coefficient was deduced. The percentage of water gain was in the range of 303–662%. The proposed model fitted better to the experimental data. The estimated diffusion coefficient was evaluated during the initial phase and at the final phase. In any cross section located along the stem of Raffia vinifera, it was found that the effective diffusion coefficient increases from the periphery to the centre during the initial and final phases. PMID:24592199

Sikame Tagne, N. R.; Njeugna, E.; Fogue, M.; Drean, J.-Y.; Nzeukou, A.; Fokwa, D.

2014-01-01

234

K? absorption by locust gut and inhibition of ileal K? and water transport by FGLamide allatostatins.  

PubMed

The scanning ion-selective electrode technique (SIET) was utilized for the first time in Locusta migratoria to characterize K(+) transport along the digestive tract and to determine the effect of two locust FGLamide allatostatins (FGLa/ASTs) on K(+) transport: a previously sequenced FGLa/AST from Schistocerca gregaria (Scg-AST-6; ARPYSFGL-NH2) and a newly sequenced FGLa/AST from L. migratoria (Locmi-FGLa/AST-2; LPVYNFGL-NH2). Regional differences in K(+) fluxes along the gut were evident, where K(+) efflux in vitro (or absorption into the hemolymph in vivo) was greatest at the anterior ileum, and lowest at the colon. Ileal K(+) efflux was inhibited by both Scg-AST-6 and Locmi-FGLa/AST-2, with maximal inhibition at 10(-10) and 10(-11) mol l(-1), respectively. Both FGLa/ASTs also inhibited cAMP-stimulated K(+) efflux from the ileum. Locmi-FGLa/AST-2 also inhibited efflux of water across the ileum. Locusts are terrestrial insects living in dry climates, risking desiccation and making water conservation a necessity. The results suggest that FGLa/ASTs may be acting as diuretics by increasing K(+) excretion and therefore increasing water excretion. Thus it is likely that FGLa/ASTs are involved in the control of hemolymph water and ion levels during feeding and digestion, to help the locust deal with the excess K(+) load (and subsequently fluid) when the meal is processed. PMID:25013112

Robertson, Lisa; Donini, Andrew; Lange, Angela B

2014-09-15

235

Mass absorption efficiency of elemental carbon and water-soluble organic carbon in Beijing, China  

NASA Astrophysics Data System (ADS)

The mass absorption efficiency (MAE) of elemental carbon (EC) in Beijing was quantified using a thermal-optical carbon analyzer. The MAE measured at 632 nm was 8.45±1.71 and 9.41±1.92 m2 g-1 during winter and summer respectively. The daily variation of MAE was found to coincide with the abundance of organic carbon (OC), especially the OC to EC ratio, perhaps due to the enhancement by coating with organic aerosol (especially secondary organic aerosol, SOA) or the artifacts resulting from the redistribution of liquid-like organic particles during the filter-based absorption measurements. Using a converting approach that accounts for the discrepancy caused by measurements methods of both light absorption and EC concentration, previously published MAE values were converted to the equivalent-MAE, which is the estimated value if using the same measurement methods as used in this study. The equivalent-MAE was found to be much lower in the regions heavily impacted by biomass burning (e.g., below 2.7 m2 g-1 for two Indian cities). Results from source samples (including diesel exhaust samples and biomass smoke samples) also demonstrated that emissions from biomass burning would decrease the MAE of EC. Moreover, optical properties of water-soluble organic carbon (WSOC) in Beijing were presented. Light absorption by WSOC exhibited strong wavelength (?) dependence such that absorption varied approximately as ?-7, which was characteristic of the brown carbon spectra. The MAE of WSOC (measured at 365 nm) was 1.79±0.24 and 0.71±0.20 m2 g-1 during winter and summer respectively. The large discrepancy between the MAE of WSOC during winter and summer was attributed to the difference in the precursors of SOA such that anthropogenic volatile organic compounds (AVOCs) should be more important as the precursors of SOA in winter. The MAE of WSOC in Beijing was much higher than results from the southeastern United States which were obtained using the same method as used in this study, perhaps due to the stronger emissions of biomass burning in China.

Cheng, Y.; He, K.-B.; Zheng, M.; Duan, F.-K.; Du, Z.-Y.; Ma, Y.-L.; Tan, J.-H.; Yang, F.-M.; Liu, J.-M.; Zhang, X.-L.; Weber, R. J.; Bergin, M. H.; Russell, A. G.

2011-11-01

236

In vivo and in vitro absorption and binding to powdered stratum corneum as methods to evaluate skin absorption of environmental chemical contaminants from ground and surface water  

Microsoft Academic Search

The objectives of this study were to compare methods to determine the binding and absorption of water contaminants to skin, to examine linearity of response, and to determine whether skin was an environmental route for water contaminants to enter the body. The three chemical examined were (¹⁴C)-p-nitroaniline (10.1 mCi\\/mM), (¹⁴C)benzene (56 mCi\\/mM, and ¹⁴C-labeled 54% PCB (32 mCi\\/mM). The chemical

Ronald C. Wester; Mohammad Mobayen; Howard I. Maibach

1987-01-01

237

Surfactant\\/oil\\/water system for the determination of selenium in eggs by graphite furnace atomic absorption spectrometry  

Microsoft Academic Search

An oil-in-water formulation has been optimized to determine trace levels of selenium in whole hen eggs by graphite furnace atomic absorption spectrometry. This method is simpler and requires fewer reagents when compared with other sample pre-treatment procedures. Graphite furnace atomic absorption spectrometric (GF AAS) measurement was carried out using standard addition calibration and Pd as a modifier. The precision, expressed

C. V. S. Ieggli; D. Bohrer; S. Noremberg; P. C. do Nascimento; L. M. de Carvalho; S. L. Vieira; R. N. Reis

2009-01-01

238

The Effect of Electrical Stimulation on the Water-Holding Capacity and Protein Denaturation of Two Bovine Muscles1  

Microsoft Academic Search

The effect of low-voltage electrical stimulation on the water-holding capacity and protein denaturation of bovine longissimus thoracis and semi- membranosus was studied in eight electrically stimu- lated (85 V, 14 Hz, 15 s; immediately after slaughter) and eight nonstimulated Friesian Holstein bull car- casses. At 24 h postmortem longissimus thoracis and semimembranosus were sampled for drip loss, thaw loss, filter

M. J. A. den Hertog-Meischke; F. J. M. Smulders; J. G. van Logtestijn; F. van Knapen

239

Genetic determinants for intramuscular fat content and water-holding capacity in mice selected for high muscle mass  

PubMed Central

Intramuscular fat content and water-holding capacity are important traits in livestock as they influence meat quality, nutritive value of the muscle, and animal health. As a model for livestock, two inbred lines of the Berlin Muscle Mouse population, which had been long-term selected for high muscle mass, were used to identify genomic regions affecting intramuscular fat content and water-holding capacity. The intramuscular fat content of the Musculus longissimus was on average 1.4 times higher in BMMI806 than in BMMI816 mice. This was accompanied by a 1.5 times lower water-holding capacity of the Musculus quadriceps in BMMI816 mice. Linkage analyses with 332 G3 animals of reciprocal crosses between these two lines revealed quantitative trait loci for intramuscular fat content on chromosome 7 and for water-holding capacity on chromosome 2. In part, the identified loci coincide with syntenic regions in pigs in which genetic effects for the same traits were found. Therefore, these muscle-weight-selected mouse lines and the produced intercross populations are valuable genetic resources to identify genes that could also contribute to meat quality in other species. PMID:21732194

Cheng, Riyan; Schmitt, Armin O.; Yang, Hyuna; de Villena, Fernando Pardo Manuel; Palmer, Abraham A.; Brockmann, Gudrun A.

2012-01-01

240

Development of minimum efficiency standards for large capacity air conditioners, and commercial water heaters, refrigerators, and freezers. Final report  

Microsoft Academic Search

The California Energy Resources Conservation and Development Commission has promulgated appliance energy efficiency standards and energy conservation standards for new construction with the objective of reducing energy consumption in the State of California. The following appliance categories are specifically addressed: large capacity air conditioners; commercial water heaters; and commercial refrigerators and freezers. The tasks that have been performed include: an

P. S. Merrill; R. J. Rettberg; R. C. Erickson; J. S. Toor

1980-01-01

241

Infiltration, water holding capacity and growth patterns of biological soil crusts on sand dunes under arid and temperate climates  

NASA Astrophysics Data System (ADS)

Water repellency and, once wetted, finer pores and grains, pore clogging as well as higher water holding capacities of biological soil crusts (BSCs) are known to inhibit infiltration and to promote surface runoff, thereby holding moisture inside the crusts and redirecting rain off the slope towards the dune base. On the other hand, available water is crucial for growth and development of crust microphytes, mosses and vascular plants. In a 2-factorial design we studied the relation between crust microstructure, infiltration and water holding capacity under arid and temperate conditions (Factor A: Climate) on BSCs sampled along a catena on mobile sand dunes (Factor B: Catena). The arid and temperate study sites were located near Nizzana, Israel (precipitation: ~80 mm a-1, PET: ~2500 mm a-1) and Lieberose, Germany (precipitation: ~600 mm a-1, PET: ~750 mm a-1), respectively. BSCs were sampled near the dune crest, at the center of the dune slope and at the dune base at each site. Scanning electron microscopy (SEM) was used to characterize BSC development and microstructure. Infiltration was determined using microinfiltrometry under controlled moisture conditions in the lab, water holding capacities were determined after water saturation of the dry BSCs. Wettability of the crusts was characterized using a "repellency index", which was calculated from water and ethanol sorptivities. It was found that thickness and density of biogenic elements in the BSCs increased downslope at each study site and correlated positively with water holding capacities and negatively with infiltration and wettability with one exception: At the dune base of the temperate site, where water holding capacity was highest, infiltration and wettability increased again due to emergence of mosses. It is hypothesized that a positive feedback between crust growth and surface runoff intensifies downslope, resulting in highest water availability in the topsoil of the dune base. Under arid conditions, low amounts of total precipitation as well as extended periods of drought preclude growth of mosses and vascular vegetation, and facilitate the development of thicker microbiotic crusts. Under temperate conditions, however, BSCs, initially present in young ecosystems at the dune base, promote favorable for moss and vascular plant growth moisture conditions, which then take over. Hence, BSC induced water redistribution has important implications for the development of vegetational patterns on a dune scale.

Fischer, T.; Yair, A.; Veste, M.

2012-04-01

242

A study of the water vapor absorption for integrating humidity sensor  

NASA Astrophysics Data System (ADS)

Humidity can damage components of electronic systems, such as missiles, so such systems must be stored in containers, which are impermeable to moisture. Conventional humidity sensors measure the current humidity level and thus can not detect if a transient high humidity level had occurred prior to the measurement. However, the output of an integrating humidity sensor reflects a past high humidity level, even if the current humidity level is low, and can be used to indicate if damage may have occurred during storage or transport. In this study, an integrating humidity sensor consisting of hygroscopic salt particles (magnesium sulfate) dispersed in a polybutadiene polymer film has been fabricated and investigated. Upon exposure to moisture, the water vapor reacts with the hygroscopic salt and results in a change of the electrical properties of the film. The change in capacitance is related to the amount of water vapor absorbed by the hybrid polymer film. Even after the humidity level is reduced, the sensor output is still different from the initial value. This reaction is irreversible so the sensor response is related to the total amount of water vapor during exposure. Electrochemical impedance spectroscopy is used to study the mechanism of water vapor absorption during sensor exposure to the humidity environment. The experimental data analyzed with complex plots and Bode plots indicate that the integrating humidity sensor exhibits a change from capacitive behavior to resistive behavior after exposure to humidity environment for 35 days later. Analysis of these impedance plots indicates that both electron charge transfer processes and diffusion processes occurred during the sensor exposure. Based on this physical understanding, the proposed equivalent circuit model was constructed using a ladder network with a transmission line model, which is called a Warburg impedance, and employed in a computer simulation to analyze the electrochemical impedance behavior of the integrating humidity sensor. The computer simulation results indicate that mass transfer diffusion processes dominate the water vapor absorption mechanism in the early exposure. However, electron charge transfer processes prevail over the diffusion process after the hygroscopic salts are saturated.

Hsu, Tingkuei

243

Comparison of x-ray absorption spectra between water and ice: new ice data with low pre-edge absorption cross-section.  

PubMed

The effect of crystal growth conditions on the O K-edge x-ray absorption spectra of ice is investigated through detailed analysis of the spectral features. The amount of ice defects is found to be minimized on hydrophobic surfaces, such as BaF2(111), with low concentration of nucleation centers. This is manifested through a reduction of the absorption cross-section at 535 eV, which is associated with distorted hydrogen bonds. Furthermore, a connection is made between the observed increase in spectral intensity between 544 and 548 eV and high-symmetry points in the electronic band structure, suggesting a more extended hydrogen-bond network as compared to ices prepared differently. The spectral differences for various ice preparations are compared to the temperature dependence of spectra of liquid water upon supercooling. A double-peak feature in the absorption cross-section between 540 and 543 eV is identified as a characteristic of the crystalline phase. The connection to the interpretation of the liquid phase O K-edge x-ray absorption spectrum is extensively discussed. PMID:25053326

Sellberg, Jonas A; Kaya, Sarp; Segtnan, Vegard H; Chen, Chen; Tyliszczak, Tolek; Ogasawara, Hirohito; Nordlund, Dennis; Pettersson, Lars G M; Nilsson, Anders

2014-07-21

244

Influence of drug physicochemical properties on absorption of water insoluble drug nanosuspensions.  

PubMed

In order to investigate the influence of drug physicochemical properties on bioavailability of water insoluble drug nanosuspensions, five drug nanosuspensions were prepared using high pressure homogenization. These nanosuspensions were similar in particle size and same in stabilizer. Differential scanning calorimetry and powder X-ray diffraction analysis showed the crystalline state of the freeze dried nanocrystals did not change. In vitro dissolution test in fasted state simulated intestinal fluid (FaSSIF) and in vivo bioavailability study in rats demonstrated that the nanosuspensions had higher dissolution rate and higher AUC0-t and the ratios of dissolvednano/dissolvedmicro in 120 min were well correlated with the ratios of AUC0-t nano/AUC0-t micro. Correlation analysis between drug physicochemical properties and AUC0-t nano was performed and four-grid interpolation method was employed for interpolation and smooth surface fitting to give a visible trend. The results revealed that drug with smaller melting point, logP value around 5 and polar surface area value in the range of 50-60 would gain higher AUC0-t nano and accordingly better absorption of its nanosuspension. Melting point, logP and polar surface area were factors that influence the absorption of drug nanosuspensions in this study. PMID:24184036

Li, Wei; Quan, Peng; Zhang, Yaqiong; Cheng, Jing; Liu, Jie; Cun, Dongmei; Xiang, Rongwu; Fang, Liang

2014-01-01

245

Revisiting the total ion yield x-ray absorption spectra of liquid water microjets.  

PubMed

Measurements of the total ion yield (TIY) x-ray absorption spectrum (XAS) of liquid water by Wilson et al (2002 J. Phys.: Condens. Matter 14 L221 and 2001 J. Phys. Chem. B 105 3346) have been revisited in light of new experimental and theoretical efforts by our group. Previously, the TIY spectrum was interpreted as a distinct measure of the electronic structure of the liquid water surface. However, our new results indicate that the previously obtained spectrum may have suffered from as yet unidentified experimental artifacts. Although computational results indicate that the liquid water surface should exhibit a TIY-XAS that is fundamentally distinguishable from the bulk liquid XAS, the new experimental results suggest that the observable TIY-XAS is actually nearly identical in appearance to the total electron yield (TEY-)XAS, which is a bulk probe. This surprising similarity between the observed TIY-XAS and TEY-XAS likely results from large contributions from x-ray induced electron stimulated desorption of ions, and does not necessarily indicate that the electronic structure of the bulk liquid and liquid surface are identical. PMID:21694286

Cappa, Christopher D; Smith, Jared D; Wilson, Kevin R; Saykally, Richard J

2008-05-21

246

Evaluation of tropospheric water vapor profiling using eye-safe, infrared differential absorption lidar  

SciTech Connect

Continuous, high quality profiles of water vapor, free of systematic bias, and of moderate temporal and spatial resolution are fundamental to the success of the ARM CART program. In addition, these should be acquired over long periods at low operational and maintenance cost. The development and verification of realistic climate model parameterizations for clouds and net radiation balance, and the correction of other CART site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. To date, application of profiles have been limited by vertical resolution and uniqueness and high operating cost, or diminished daytime performance, lack of eye-safety, and high maintenance cost. Recent developments in infrared laser and detector technology make possible compact IR differential absorption lidar (DIAL) systems at eye-safe wavelengths. In the studies reported here, we develop DIAL system performance models and examine the potential of solving some of the shortcomings of previous methods using parameters representative of current technologies. These simulations are also applied to determine the strengths and weaknesses unique to the DIAL method for this application.

Rye, B.J. [Colorado Univ., Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences]|[National Oceanic and Atmospheric Administration, Boulder, CO (United States). Environmental Technology Lab.; Machol, J.L.; Grund, C.J.; Hardesty, R.M. [National Oceanic and Atmospheric Administration, Boulder, CO (United States). Environmental Technology Lab.

1996-05-14

247

Diffusion Coefficients of Water and Leachables in Methacrylate-based Crosslinked Polymers using Absorption Experiments  

PubMed Central

The diffusion of water into dentin adhesive polymers and leaching of unpolymerized monomer from the adhesive are linked to their mechanical softening and hydrolytic degradation. Therefore, diffusion coefficient data are critical for the mechanical design of these polymeric adhesives. In this study, diffusion coefficients of water and leachables were obtained for sixteen methacrylate-based crosslinked polymers using absorption experiments. The experimental mass change data was interpreted using numerical solution of the two-dimensional diffusion equations. The calculated diffusion coefficients varied from 1.05 × 10?8 cm2/sec (co-monomer TMTMA) to 3.15 × 10?8 cm2/sec (co-monomer T4EGDMA). Correlation of the diffusion coefficients with crosslink density and hydrophilicity showed an inverse trend (R2 = 0.41). The correlation of diffusion coefficient with crosslink density and hydrophilicity are closer for molecules differing by simple repeat units (R2 = 0.95). These differences in the trends reveal mechanisms of interaction of the diffusing water with the polymer structure. PMID:22430592

Parthasarathy, Ranganathan; Misra, Anil; Park, Jonggu; Ye, Qiang; Spencer, Paulette

2012-01-01

248

Ground-based differential absorption lidar for water-vapor and temperature profiling: methodology.  

PubMed

A comprehensive formulation of the differential absorption lidar (DIAL) methodology is presented that explicitly includes details of the spectral distributions of both the transmitted and the backscattered light. The method is important for high-accuracy water-vapor retrievals and in particular for temperature measurements. Probability estimates of the error that is due to Doppler-broadened Rayleigh scattering based on an extended experimental data set are presented, as is an analytical treatment of errors that are due to averaging in the nonlinear retrieval scheme. System performance requirements are derived that show that water-vapor retrievals with an accuracy of better than 5% and temperature retrievals with an accuracy of better than 1 K in the entire troposphere are feasible if the error that results from Rayleigh-Doppler correction can be avoided. A modification of the DIAL technique, high-spectral-resolution DIAL avoids errors that are due to Doppler-broadened Rayleigh backscatter and permits simultaneous water-vapor and wind measurements with the same system. PMID:18273353

Bösenberg, J

1998-06-20

249

Water absorption of poly(methyl methacrylate) measured by vertical interference microscopy.  

PubMed

PMMA (poly(methyl methacrylate)) is widely used to prepare orthopedic cements. They are in direct contact with cells and body fluids. PMMA, despite its hydrophobic nature, can absorb ~2% w/w water. We have evaluated by vertical interference microscopy if water absorption can produce a significant swelling in different types of PMMA blocks: pure, with a plasticizer, with a cross-linker, and in two types of commercial bone cements. Graphite rods which do not swell in water were used as internal standard. Hardness, indentation modulus, plastic, and elastic works were determined by nanoindentation under a 25mN fixed force. Vertical interference microscopy was used to image the polymer in the dry state and hydrated states (after 24 h in distilled water). On the surface of the polished polymers (before and after hydration), we measured roughness by the fractal dimension, the swelling in the vertical and the lateral directions. For each polymer block, four images were obtained and values were averaged. Comparison and standardization of the images in the dry and hydrated states were done with Matlab software. The average value measured on the graphite rod between the two images (dried and hydrated) was used for standardization of the images which were visualized in 3D. After grinding, a small retraction was noticeable between the surface of the rod and the polymers. A retraction ring was also visible around the graphite rod. After hydration, only the pure PMMA and bone cements had a significant swelling in the vertical direction. The presence of polymer beads in the cements limited the swelling in the lateral direction. Swelling parameters correlated with the nanoindentation data. PMMA can swell by absorbing a small amount of water and this induces a swelling that varies with the polymer composition and particle inclusions. PMID:22799564

N'Diaye, Mambaye; Pascaretti-Grizon, Florence; Massin, Philippe; Baslé, Michel Felix; Chappard, Daniel

2012-08-01

250

Predictions of silicon avalanche photodiode detector performance in water vapor differential absorption lidar  

NASA Technical Reports Server (NTRS)

Performance analyses are presented which establish that over most of the range of signals expected for a down-looking differential absorption lidar (DIAL) operated at 16 km the silicon avalanche photodiode (APD) is the preferred detector for DIAL measurements of atmospheric water vapor in the 730 nm spectral region. The higher quantum efficiency of the APD's, (0.8-0.9) compared to a photomultiplier's (0.04-0.18) more than offsets the higher noise of an APD receiver. In addition to offering lower noise and hence lower random error the APD's excellent linearity and impulse recovery minimize DIAL systematic errors attributable to the detector. Estimates of the effect of detector system parameters on overall random and systematic DIAL errors are presented, and performance predictions are supported by laboratory characterization data for an APD receiver system.

Kenimer, R. L.

1988-01-01

251

Determination of barium in bottled drinking water by graphite furnace atomic absorption spectrometry  

SciTech Connect

In relation to the wide environmental spread of barium and to its cardiovascular effects, barium levels were determined by graphite furnace atomic absorption spectrometry in 60 different brands of bottled water marketed in Italy. Matrix interferences were investigated in order to evaluate the use of an analytical calibration function rather than the much more time consuming addition technique. The barium content ranged from limit of detection C/sub L/ (7.0 ..mu..g/1) up to 660 ..mu..g/1, the median value being 80 ..mu..g/l, while the recovery tests varied between 90 and 110% and the precision of the method (s/sub yx/) was 2.5%.

Fagioli, F.; Locatelli, C.; Lanciotti, E.; Vallone, G.; Mazzotta, D.; Mugelli, A.

1988-11-01

252

VARIABILITY OF WATER AND OXYGEN ABSORPTION BANDS IN THE DISK-INTEGRATED SPECTRA OF EARTH  

SciTech Connect

We study the variability of major atmospheric absorption features in the disk-integrated spectra of Earth with future application to Earth-analogs in mind, concentrating on the diurnal timescale. We first analyze observations of Earth provided by the EPOXI mission, and find 5%-20% fractional variation of the absorption depths of H{sub 2}O and O{sub 2} bands, two molecules that have major signatures in the observed range. From a correlation analysis with the cloud map data from the Earth Observing Satellite (EOS), we find that their variation pattern is primarily due to the uneven cloud cover distribution. In order to account for the observed variation quantitatively, we consider a simple opaque cloud model, which assumes that the clouds totally block the spectral influence of the atmosphere below the cloud layer, equivalent to assuming that the incident light is completely scattered at the cloud top level. The model is reasonably successful, and reproduces the EPOXI data from the pixel-level EOS cloud/water vapor data. A difference in the diurnal variability patterns of H{sub 2}O and O{sub 2} bands is ascribed to the differing vertical and horizontal distribution of those molecular species in the atmosphere. On Earth, the inhomogeneous distribution of atmospheric water vapor is due to the existence of its exchange with liquid and solid phases of H{sub 2}O on the planet's surface on a timescale short compared with atmospheric mixing times. If such differences in variability patterns were detected in spectra of Earth-analogs, it would provide the information on the inhomogeneous composition of their atmospheres.

Fujii, Yuka; Suto, Yasushi [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Turner, Edwin L., E-mail: yuka.fujii@utap.phys.s.u-tokyo.ac.jp [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

2013-03-10

253

The influence of water vapor on atmospheric exchange measurements with an ICOS* based Laser absorption analyzer  

NASA Astrophysics Data System (ADS)

Carbonyl sulfide and carbon monoxide are both atmospheric trace gases of high interest. Recent advances in the field of spectroscopy have enabled instruments that measure the concentration of the above and other trace gases very fast and with good precision. Increasing the effective path length by reflecting the light between two mirrors in a cavity, these instruments reach impressive sensitivities. Often it is possible to measure the concentration of more than one trace gas at the same time. The OCS/CO2 Analyzer by LGR (Los Gatos Research, Inc.) measures the concentration of water vapor [H2O], carbonyl sulfide [COS], carbon dioxide [CO2] and carbon monoxide [CO] simultaneously. For that the cavity is saturated with light, than the attenuation of light is measured as in standard absorption spectroscopy. The instrument proved to be very fast with good precision and to be able to detect even very low concentrations, especially for COS (as low as 30ppt in the case of COS). However, we observed a rather strong cross sensitivity to water vapor. Altering the water vapor content of the sampled air with two different methods led to a change in the perceived concentration of COS, CO and CO2. This proved especially problematic for enclosure (cuvette) measurements, where the concentrations of one of the above species in an empty cuvette are compared to the concentration of another cuvette containing a plant whose exchange of trace gases with the atmosphere is of interest. There, the plants transpiration leads to a large difference in water vapor content between the cuvettes and that in turn produces artifacts in the concentration differences between the cuvettes for the other above mentioned trace gases. For CO, simultaneous measurement with a UV-Emission Analyzer (AL 5002, Aerolaser) and the COS/CO Analyzer showed good agreement of perceived concentrations as long as the sample gas was dry and an increasing difference in perceived concentration when the sample gas was humidified. The difference in perceived CO concentration showed a clear correlation to the water vapor content in the sample air. For COS we could show that changes in water vapor also impacted on the perceived COS concentrations; the raise of the water vapor concentration would lead to an increasing underestimation of the COS concentration. Drying the air using a Nafion Dryer before entering the COS/CO Analyzer eliminated any water vapor induced artifacts and showed no adverse effects on the quality of the conducted measurements. *Integrated cavity output spectroscopy

Bunk, Rüdiger; Quan, Zhi; Wandel, Matthias; Yi, Zhigang; Bozem, Heiko; Kesselmeier, Jürgen

2014-05-01

254

A three-dimensional water quality model to evaluate the environmental capacity of nitrogen and phosphorus in Jiaozhou Bay, China.  

PubMed

Jiaozhou Bay has recently suffered from serious problems with pollution and eutrophication. Thus, land-based pollutant load must be reduced through a national control program. In this study, we developed a 3D water quality model to determine the environmental capacity of nitrogen and phosphorus in Jiaozhou Bay. A 3D hydrodynamic model (the estuarine, coastal, and ocean modeling system with sediments) was coupled with a water quality model, which was adapted from the dynamic model of nitrogen and phosphorus for a mesocosm near Jiaozhou Bay. The water quality model is divided into seven components: dissolved inorganic nitrogen, phosphate, phytoplankton, zooplankton, detritus, dissolved organic nitrogen, and dissolved organic phosphorus. Furthermore, it was calibrated based on data collected from Jiaozhou Bay in 2003. The proposed model effectively reproduced the spatiotemporal variability in nutrient concentration, thus suggesting that a reasonable numerical representation of the prototype system must be developed for further evaluation of environmental capacity. PMID:25549824

Li, Keqiang; Zhang, Li; Li, Yan; Zhang, Longjun; Wang, Xiulin

2015-02-15

255

Influence of wave and current flow on sediment-carrying capacity and sediment flux at the water-sediment interface.  

PubMed

In nearshore waters, spatial and temporal scales of waves, tidal currents, and circulation patterns vary greatly. It is, therefore, difficult to combine these factors' effects when trying to predict sediment transport processes. This paper proposes the concept of significant wave velocity, which combines the effects of waves, tides, and ocean currents using the horizontal kinetic energy superposition principle. Through a comparison of the relationship between shear stress at the water-sediment interface and sediment-carrying capacity, assuming equilibrium sediment flux, a new formula for sediment-carrying capacity, which incorporates the concept of significant wave velocities, is derived. Sediment-carrying capacity is a function of the critical velocity, which increases with water depth and decreases with increasing relative roughness of the sea bed. Finally, data from field observation stations and simulations are used to test the proposed formula. The results show that the new formula is in good agreement with both field and simulation data. This new formula for sediment-carrying capacity can be used to simulate nearshore sediment transport. PMID:25259499

Zheng, Jun; Li, Ruijie; Yu, Yonghai; Suo, Anning

2014-01-01

256

Effect of pH, phosphorus, and water-extractable zinc of soil on plant growth and zinc absorption  

E-print Network

EFFECT OF pH~ PHOSPHORilS, AND WATER-EXTRACTABLE ZINC OF SOIL ON PLANT GROWTH AND ZINC ABSORPT1ON A Thesis Najafali Karimian Submitted to the Graduate College cf Texas ARM University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE December 1970 Major Sub ject: Soil Chemistry EFFECT OF pH, PHOSPHORUS, AND WATER-EXTRACTABLE ZINC OF SOIL ON PLANT GROWTH AND ZINC ABSORPTION A Thesis by NajafaIi Karimian Approved as to sty1e and content by: Chairman Committee...

Karimian, Najafali

1970-01-01

257

Collaboration with HEIs: A Key Capacity Building Block for the Uganda Water and Sanitation Public Sector  

ERIC Educational Resources Information Center

The capacity of public service staff in developing countries is crucial for achieving the Millennium Development Goals. Literature from developed countries shows that, working with higher education institutions (HEIs), industries have improved their human resource capacity through continuing professional development. This paper reports on research…

Kayaga, Sam

2007-01-01

258

In air synthesis of Psy-cl-poly(AAm) network and its application in water-absorption from oil-water emulsions  

Microsoft Academic Search

In this current investigation psyllium has been functionalized with acrylamide in the presence of potassium per- sulphate (KPS)-hexamethylene tetramine (HMTA) as an initiator-crosslinker system. After the initial optimization of dif- ferent reaction parameters the resultant hydrogel was used for the absorption of water from different water-oil emulsions as a function of time, temperature, pH and NaCl concentration. 4216% of water

B. S. Kaith; K. Kumar

2007-01-01

259

Increased intestinal absorption of insulin in a micellar solution: water-in-oil-in-water insulin micelles.  

PubMed

Water-in-oil-in-water (W/O/W) insulin micelles were prepared, and the possibility of insulin absorption in a micellar form was examined. In this preparation, insulin was trapped in oil droplets of oleic acid in glyceryl-alpha-monooleate. (1) W/O/W insulin micelles were absorbed from the ligated jejunal loop of rabbits to the order of 12.3 to 58.5% of the dose given (10 mU/kg body weight) during the 3-h experimental period. (2) Alloxan diabetic rats were treated with intrajejunal administration of W/O/W insulin micelles at a dosage of either 25 or 50 mU/100 g body weight, three times daily for as long as 14 days. During treatment, a significant reduction in the daily excretion of urinary glucose was observed, concomitant with a decrease in fasting blood glucose. Quantitative estimates suggested that the effectiveness of 25 mU/100 g of intrajejunal W/O/W insulin micelles was comparable to that of regular insulin at a dosage of 1 mU/100 g i.m. These results would indicate that W/O/W insulin micelles, when given enterally, are more effective in lowering blood and urinary glucose levels than W/O/W insulin emulsions in which insulin was trapped in oil droplets of triglyceride. PMID:707000

Shichiri, M; Kawamori, R; Goriya, Y; Kikuchi, M; Yamasaki, Y; Shigeta, Y; Abe, H

1978-01-01

260

A theoretical investigation of gaseous absorption by water droplets from SO2-HNO3-NH3-CO2-HCl mixtures  

NASA Technical Reports Server (NTRS)

A physical-chemical model is developed and used to investigate gaseous absorption by water droplets from trace gas mixtures. The model is an extension of that of Carmichael and Peters (1979) and includes the simultaneous absorption of SO2, NH3, HNO3, CO2, and HCl. Gas phase depletion is also considered. Presented results demonstrate that the absorption behavior of raindrops is strongly dependent on drop size, fall distance, trace gas concentrations, and the chemical and physical properties of the constituents of the mixture. In addition, when gas phase depletion is considered, the absorption rates and equilibrium values are also dependent on the precipitation rate itself. Also, the trace constituents liquid phase concentrations may be a factor of six or more lower when gas depletion is considered then when the depletion is ignored. However, the hydrogen ion concentration may be insensitive to the gas phase depletion.

Adewuyi, Y. G.; Carmichael, G. R.

1982-01-01

261

Effect of a Disintegration Mechanism on Wetting, Water Absorption, and Disintegration Time of Orodispersible Tablets  

PubMed Central

The aim of this study was to evaluate the influence of disintegration mechanism of various types of disintegrants on the absorption ratio (AR), wetting time (WT), and disintegration time (DT) of orodispersible tablets (ODTs). ODTs were prepared by direct compression using mannitol as filler and disintegrants selected from a range of swellable, osmotic, and porous disintegrants. Tablets formed were characterized for their water AR, WT, and DT. The porosity and mechanical strength of the tablets were also measured. Results show that the DT of formulated ODTs was directly related to the WT and was a function of the disintegration mechanism of the disintegrant used. The lowest WT and DT were observed for tablets formulated using the osmotic disintegrant sodium citrate and these tablets also showed the lowest AR and porosity. The wetting and disintegration of tablets containing the highly swellable disintegrant, sodium starch glycollate, was slowest despite their high water AR and high tablet porosity. Rapid wetting and disintegration of ODTs were therefore not necessarily related to the porosity of the tablets. PMID:23112534

Pabari, RM; Ramtoola, Z

2012-01-01

262

Light tracking through ice and water—Scattering and absorption in heterogeneous media with PHOTONICS  

NASA Astrophysics Data System (ADS)

In the field of neutrino astronomy, large volumes of optically transparent matter like glacial ice, lake water, or deep ocean water are used as detector media. Elementary particle interactions are studied using in situ detectors recording time distributions and fluxes of the faint photon fields of Cherenkov radiation generated by ultra-relativistic charged particles, typically muons or electrons. The PHOTONICS software package was developed to determine photon flux and time distributions throughout a volume containing a light source through Monte Carlo simulation. Photons are propagated and time distributions are recorded throughout a cellular grid constituting the simulation volume, and Mie scattering and absorption are realised using wavelength and position dependent parameterisations. The photon tracking results are stored in binary tables for transparent access through ANSI-C and C++ interfaces. For higher-level physics applications, like simulation or reconstruction of particle events, it is then possible to quickly acquire the light yield and time distributions for a pre-specified set of light source and detector properties and geometries without real-time photon propagation. In this paper the PHOTONICS light propagation routines and methodology are presented and applied to the IceCube and ANTARES neutrino telescopes. The way in which inhomogeneities of the Antarctic glacial ice distort the signatures of elementary particle interactions, and how PHOTONICS can be used to account for these effects, is described.

Lundberg, J.; Mio?inovi?, P.; Woschnagg, K.; Burgess, T.; Adams, J.; Hundertmark, S.; Desiati, P.; Niessen, P.

2007-11-01

263

Atmospheric Pre-Corrected Differential Absorption Techniques to Retrieve Columnar Water Vapor: Application to AVIRIS 91/95 Data  

NASA Technical Reports Server (NTRS)

Water vapor is one of the main forces for weather development as well as for mesoscale air transport processes. The monitoring of water vapor is therefore an important aim in remote sensing of the atmosphere. Current operational systems for water vapor detection use primarily the emission in the thermal infrared (AVHRR, GOES, ATSR, Meteosat) or in the microwave radiation bands (DMSP). The disadvantage of current satellite systems is either a coarse spatial (horizontal) resolution ranging from one to tens of kilometers or a limited insight into the lower atmosphere. Imaging spectrometry on the other hand measures total column water vapor contents at a high spatial horizontal resolution and has therefore the potential of filling these gaps. The sensors of the AVIRIS instrument are capable of acquiring hyperspectral data in 224 bands located in the visible and near infrared at 10 nm resolution. This data includes the information on constituents of the earth's surface as well as of the atmosphere. The optical measurement of water vapor can be performed using sensor channels located in bands or lines of the absorption spectrum. The AVIRIS sensor has been used to retrieve water vapor and with less accuracy carbon dioxide, oxygen and ozone. To retrieve the water vapor amount, the so called differential absorption technique has been applied. The goal of this technique is to eliminate background factors by taking a ratio between channels within the absorption band and others besides the band. Various ratioing methods on the basis of different channels and calculation techniques were developed. The influence of a trace gas of interest on the radiance at the sensor level is usually simulated by using radiative transfer codes. In this study, the spectral transmittance and radiance are calculated by MODTRAN3 simulations with the new DISORT option. The objective of this work is to test the best performing differential absorption techniques for imaging spectrometry of tropospheric water vapor.

Schlaepfer, Daniel; Borel, Christoph C.; Keller, Johannes; Itten, Klaus I.

1996-01-01

264

Diode-pumped tunable narrow-linewidth Cr:LiSAF lasers for water vapor differential absorption lidars  

Microsoft Academic Search

Diode-pumped, tunable Cr:LiSAF lasers are well suited for airborne water vapor differential absorption lidar application. Three types of diode-pumped, tunable, narrow- linewidth, injection seeded, Q-switched Cr:LiSAF lasers for high resolution atmosheric water vapor DIAL measurements in the wavelength range of 810-830 nm have been developed and investigated. By using a total internal reflection laser resonator configuration, efficient coupling of pump

Victor A. Fromzel; Valery V. Ter-Mikirtychev; Joseph S. Smucz; Coorg R. Prasad; Christyl C. Johnson; Norman P. Barnes; James C. Barnes; Russell DeYoung

2001-01-01

265

Future Performance of Ground-Based and Airborne Water-Vapor Differential Absorption Lidar. I. Overview and Theory  

Microsoft Academic Search

The performance of a future advanced water-vapor differential absorption lidar (DIAL) system is discussed. It is shown that the system has to be a direct-detection system operating in the band of water vapor in the 940-nm wavelength region. The most important features of the DIAL technique are introduced: its clear-air measurement capability, its flexibility, and its simultaneous high resolution and

Volker Wulfmeyer; Craig Walther

2001-01-01

266

Sources and light absorption of water-soluble organic carbon aerosols in the outflow from northern China  

NASA Astrophysics Data System (ADS)

High loadings of anthropogenic carbonaceous aerosols in Chinese air influence the air quality for over one billion people and impact the regional climate. A large fraction (17-80%) of this aerosol carbon is water-soluble, promoting cloud formation and thus climate cooling. Recent findings, however, suggest that water-soluble carbonaceous aerosols also absorb sunlight, bringing additional direct and indirect climate warming effects, yet the extent and nature of light absorption by this water-soluble "brown carbon" and its relation to sources is poorly understood. Here, we combine source estimates constrained by dual carbon isotopes with light-absorption measurements of water-soluble organic carbon (WSOC) for a March 2011 campaign at the Korea Climate Observatory at Gosan (KCOG), a receptor station in SE Yellow Sea for the outflow from northern China. The mass absorption cross section at 365 nm (MAC365) of WSOC for air masses from N. China were in general higher (0.8-1.1 m2 g-1), than from other source regions (0.3-0.8 m2 g-1). However, this effect corresponds to only 2-10% of the radiative forcing caused by light absorption by elemental carbon. Radiocarbon constraints show that the WSOC in Chinese outflow had significantly higher fraction fossil sources (30-50%) compared to previous findings in S. Asia, N. America and Europe. Stable carbon (?13C) measurements were consistent with aging during long-range air mass transport for this large fraction of carbonaceous aerosols.

Kirillova, E. N.; Andersson, A.; Han, J.; Lee, M.; Gustafsson, Ö.

2014-02-01

267

The role of skin absorption as a route of exposure for volatile organic compounds (VOCs) in drinking water  

Microsoft Academic Search

Assessments of drinking water safety rely on the assumption that ingestion represents the principal route of exposure. A review of the experimental literature revealed that skin penetration rates for solvents are remarkably high, and that the stratum corneum is a less effective barrier to penetration than traditionally assumed. Based on published skin absorption rates, we used Fick's law (Jos .

H. S. Brown; D. R. Bishop; C. A. Rowan

1984-01-01

268

Heat capacity and structure of concentrated solutions of potassium bromide in mixtures of water and isopropyl alcohol  

Microsoft Academic Search

The specific heat capacities of solutions of potassium bromide in mixtures of water and isopropyl alcohol at 25~ were measured by means of a differential adiabatic calorimeter [1-2] with an accuracy of , 0.02%. Electrolyte concentrations ranging from pure solvents to saturated solutions and solvent compositions up to 0.23 mole fraction of isopropyl alcohol were investigated. Changes in the heat

V. I. Klopov; A. M. Kolker; G. A. Krestov

1975-01-01

269

The maximum water storage capacities in nominally anhydrous minerals in the mantle transition zone and lower mantle  

NASA Astrophysics Data System (ADS)

Water is the most important volatile component in the Earth, and affects the physicochemical properties of mantle minerals, e.g. density, elastic property, electrical conductivity, thermal conductivity, rheological property, melting temperature, melt composition, element partitioning, etc. So many high pressure experiments have been conducted so far to determine the effect of water on mantle minerals. To clarify the maximum water storage capacity in nominally anhydrous mantle minerals in the mantle transition zone and lower mantle is an important issue to discuss the possibility of the existence of water reservoir in the Earth mantle. So we have been clarifying the maximum water storage capacity in mantle minerals using MA-8 type (KAWAI-type) high pressure apparatus and SIMS (secondary ion mass spectroscopy). Upper mantle mineral, olivine can contain ~0.9 wt% H2O in the condition just above 410 km discontinuity in maximum (e.g. Chen et al., 2002; Smyth et al., 2006). On the other hand, mantle transition zone mineral, wadsleyite and ringwoodite can contain significant amount (about 2-3 wt.%) of H2O (e.g. Inoue et al., 1995, 1998, 2010; Kawamoto et al., 1996; Ohtani et al., 2000). But the lower mantle mineral, perovskite can not contain significant amount of H2O, less than ~0.1 wt% (e.g. Murakami et al., 2002; Inoue et al., 2010). In addition, garnet and stishovite also can not contain significant amount of H2O (e.g. Katayama et al., 2003; Mookherjee and Karato, 2010; Litasov et al., 2007). On the other hand, the water storage capacities of mantle minerals are supposed to be significantly coupled with Al by a substitution with Mg2+, Si4+ or Mg2+ + Si4+, because Al3+ is the trivalent cation, and H+ is the monovalent cation. To clarify the degree of the substitution, the water contents and the chemical compositions of Al-bearing minerals in the mantle transition zone and the lower mantle were also determined in the Al-bearing systems with H2O. We will introduce the recent results on the maximum water storage capacities in nominally anhydrous minerals in the mantle transition zone and lower mantle from the high pressure experimental point of view.

Inoue, T.; Yurimoto, H.

2012-12-01

270

Selective absorption of water from different oil-water emulsions with Psy-cl-poly(AAm) synthesized using irradiation copolymerization method  

Microsoft Academic Search

The present paper deals with the functionalization of psyllium with acrylamide under the influence of gamma radiation using\\u000a hexamethylene tetramine as a crosslinker. The polymer synthesized was characterized using FTIR spectroscopy, scanning electron\\u000a microscopy and thermogravimetric analysis. The superabsorbent was then used further for the selective absorption of water\\u000a from different oil-water emulsions.

B. S. Kaith; Kiran Kumar

2007-01-01

271

How to remove the influence of trace water from the absorption spectra of SWNTs dispersed in ionic liquids  

PubMed Central

Summary Single-walled carbon nanotubes (SWNTs) can be efficiently dispersed in the imidazolium-based ionic liquids (ILs), at relatively high concentration, with their intrinsic structure and properties retained. Due to the hygroscopicity of the ILs, water bands may be introduced in the absorption spectra of IL-dispersed SWNTs and cause problems in spectral deconvolution and further analysis. In order to remove this influence, a quantitative characterization of the trace water in [BMIM]+[PF6]? and [BMIM]+[BF4]? was carried out by means of UV–vis-NIR absorption spectroscopy. A simple yet effective method involving spectral subtraction of the water bands was utilized, and almost no difference was found between the spectra of the dry IL-dispersed SWNT samples treated under vacuum for 10 hours and the spectra of the untreated samples with subtraction of the pure water spectrum. This result makes it more convenient to characterize SWNTs with absorption spectra in the IL-dispersion system, even in the presence of trace amount of water. PMID:22003471

Zhang, Daqi

2011-01-01

272

The dynamic viscoelasticity and water absorption characteristics of soft acrylic resin materials containing adipates and a maleate plasticizer.  

PubMed

The purpose of this study was to investigate the use of different plasticizers in soft acrylic resin materials to reduce leaching of the plasticizer and thus increase the durability of tissue conditioners. Samples were prepared containing different combinations of three types of polymer/copolymer powder and four types of plasticizer liquid (DEHM, DIBA, DAA and DINA). The dynamic viscoelasticity of each sample was measured after water immersion using a dynamic mechanical analyzer. Water absorption, solubility and weight change were also measured. A significant difference was found among the materials regarding dynamic viscoelasticity, water absorption and solubility. The samples containing P-n-BMA had the most stable G' and G'' scores throughout the immersion. P-n-BMA is the most suitable powder together with DEHM as the most suitable liquid component for a tissue conditioner. These results suggest that it is possible to improve the durability of tissue conditioners by combining different polymers and plasticizers. PMID:22277618

Hong, Guang; Tsuka, Hiroki; Maeda, Takeshi; Akagawa, Yasumasa; Sasaki, Keiichi

2012-02-01

273

Recent advances in carrier-mediated intestinal absorption of water-soluble vitamins.  

PubMed

Significant progress has been made in recent years toward understanding the mechanisms and regulation of intestinal absorption of water-soluble vitamins from the diet, especially those that are transported by a specialized carrier-mediated mechanism (i.e., ascorbic acid, biotin, folate, riboflavin, thiamin, and pyridoxine). The driving force involved in the uptake events and the molecular identity of the systems involved have been identified for a number of these vitamins. In addition, information about regulation of the uptake process of these micronutrients by intracellular and extracellular factors has been forthcoming. Furthermore, the 5' regulatory region of the genes that encode a number of these transporters has been characterized, thus providing information about transcriptional regulation of the transport events. Also of interest is the identification of existence of carrier-mediated mechanisms in human colonocytes that are capable of absorbing some of the vitamins that are synthesized by normal microflora of the large intestine. Although the contribution of the latter source of vitamins toward overall host nutrition is not clear and requires further investigations, it is highly likely that it does contribute toward the cellular homeostasis of these vitamins in the localized colonocytes. PMID:14977409

Said, Hamid M

2004-01-01

274

New absorption-based optode for the detection of Hg(II) in water  

NASA Astrophysics Data System (ADS)

The current paper describes a novel absorption-based optode for mercury (II) detection. The dye 2-(5-amino-3,4-dicyano- 2H-pyrrol-2-ylidene)-1,1,2-tricyanoethanide (L') is a specific ligand for Hg2+ in water, undergoing a color change from violet to blue on the formation of the corresponding monochelated complex HgL. The dye L' was fixed on different supports by means of anionic exchange. Controlled pore glasses, cross-linked styrene and cellulose paper were used as supports and two different optode configurations were developed in order to couple them to the optical fibers. Photodegradation and leakage of the dye were thoroughly investigated by means of an accurate spectrophotometric analysis in the presence of mercury acetate [Hg(AcO)2] solutions. In order to reduce the photodegradation of the dye, an optoelectronic unit was developed using light-emitting diodes as sources and a suitable electronic circuit as the detecting system.

Baldini, Francesco; Falai, Alida; Flamini, Alberto; Mencaglia, Andrea A.

1999-02-01

275

Ultra Narrowband Optical Filters for Water Vapor Differential Absorption Lidar (DIAL) Atmospheric Measurements  

NASA Technical Reports Server (NTRS)

Differential absorption lidar (DIAL) systems are being deployed to make vertical profile measurements of atmospheric water vapor from ground and airborne platforms. One goal of this work is to improve the technology of such DIAL systems that they could be deployed on space-based platforms. Since background radiation reduces system performance, it is important to reduce it. One way to reduce it is to narrow the bandwidth of the optical receiver system. However, since the DIAL technique uses two or more wavelengths, in this case separated by 0.1 nm, a fixed-wavelength narrowband filter that would encompass both wavelengths would be broader than required for each line, approximately 0.02 nm. The approach employed in this project is to use a pair of tunable narrowband reflective fiber Bragg gratings. The Bragg gratings are germanium-doped silica core fiber that is exposed to ultraviolet radiation to produce index-of-refraction changes along the length of the fiber. The gratings can be tuned by stretching. The backscattered laser radiation is transmitted through an optical circulator to the gratings, reflected back to the optical circulator by one of the gratings, and then sent to a photodiode. The filter reflectivities were >90 percent, and the overall system efficiency was 30 percent.

Stenholm, Ingrid; DeYoung, Russell J.

2001-01-01

276

Laser absorption spectroscopy of water vapor confined in nanoporous alumina: wall collision line broadening and gas diffusion dynamics.  

PubMed

We demonstrate high-resolution tunable diode laser absorption spectroscopy (TDLAS) of water vapor confined in nanoporous alumina. Strong multiple light scattering results in long photon pathlengths (1 m through a 6 mm sample). We report on strong line broadening due to frequent wall collisions (gas-surface interactions). For the water vapor line at 935.685 nm, the HWHM of confined molecules are about 4.3 GHz as compared to 2.9 GHz for free molecules (atmospheric pressure). Gas diffusion is also investigated, and in contrast to molecular oxygen (that moves rapidly in and out of the alumina), the exchange of water vapor is found very slow. PMID:20721033

Svensson, Tomas; Lewander, Märta; Svanberg, Sune

2010-08-01

277

Solid phase extraction and graphite furnace atomic absorption spectrometric determination of ultra trace amounts of bismuth in water samples.  

PubMed

A simple and reliable method for the selective extraction and determination of bismuth in water as well as alloy samples using octadecyl bonded silica cartridge modified with cyanex 301 and graphite furnace atomic absorption spectrometry is described. Extraction efficiency and influence of sample matrix, optimum amount of extraction ligand, type and least amount of proper eluent and flow rates were evaluated. The limit of detection of the proposed method is 0.01 ng ml(-1). The influence of potential interfering cations in water samples on the recovery of bismuth was investigated. The method was successfully applied to the extraction and determination of bismuth in natural water and alloy samples. PMID:18968557

Yamini, Yadollah; Chaloosi, Marzieh; Ebrahimzadeh, Homeira

2002-03-11

278

Impact of the hydraulic capacity of plants on water and carbon fluxes in tropical South America  

E-print Network

capacity of angiosperms played a significant role in the expansion of tropical rain forest. Citation: Lee the Amazon basin. Transpiration triggers convection by increasing moisture in the boundary layer and thereby climate, and the eastern part of the Amazon basin becomes wet (200 mm/month of precipitation). This double

Boyce, C. Kevin

279

Geophysical imaging of watershed subsurface patterns and prediction of soil texture and water holding capacity  

Microsoft Academic Search

The spatial distribution of subsurface soil textural properties across the landscape is an important control on the hydrological and ecological function of a watershed. Traditional methods of mapping soils involving subjective assignment of soil boundaries are inadequate for studies requiring a quantitative assessment of the landscape and its subsurface connectivity and storage capacity. Geophysical methods such as electromagnetic induction (EMI)

H. Abdu; D. A. Robinson; M. Seyfried; S. B. Jones

2008-01-01

280

Toward improving estimates of field soil water capacity from laboratory-measured soil properties  

Technology Transfer Automated Retrieval System (TEKTRAN)

Different recommendations exist world-wide on which – if any - pressure head should be used in laboratory measurements to approximate the ‘field capacity’ (FC) of the soil. Literature often deems any such pressure heads to be inadequate to approximate FC for soils of all textures. We used a data col...

281

Water-vapor absorption line measurements in the 940-nm band by using a Raman-shifted dye laser.  

PubMed

We report water-vapor absorption line measurements that are made by using the first Stokes radiation (930-982 nm) with HWHM 0.015 cm(-1) generated by a narrow-linewidth, tunable dye laser. Forty-five absorption line strengths are measured with an uncertainty of 6% and among them are fourteen strong lines that are compared with previous measurements for the assessment of spectral purity of the light source. Thirty air-broadened linewidths are measured with 8% uncertainty at ambient atmospheric pressure with an average of 0.101 cm(-1). The lines are selected for the purpose of temperature-sensitive or temperature-insensitive lidar measurements. Results for these line strengths and linewidths are corrected for broadband radiation and finite laser linewidth (0.015 cm(-1) HWHM) broadening effects and compared with the high-resolution transmission molecular absorption. PMID:20802779

Chu, Z; Wilkerson, T D; Singh, U N

1993-02-20

282

The influence of recycled expanded polystyrene (EPS) on concrete properties: Influence on flexural strength, water absorption and shrinkage  

NASA Astrophysics Data System (ADS)

Expanded polystyrene waste in a granular form was used as a lightweight aggregate in order to produce lightweight concretë Lightweight EPS concrete composites were produced by replacing the coarse aggregate, either partially or fully with equal volume of EPS aggregates. The coarse aggregate replacements levels used were 25, 50, 75, and 100%, which corresponded to (9.20, 18.40, 27.60, and 36.8%) from total volume. The investigation is directed towards the development and performance evaluation of the concrete composites containing EPS aggregates, without addition of either bonding additives, or super-plasticizers on some concrete properties such as flexure strength, water absorption and change in length (or shrinkage). Experimental results showed that a density reduction of 12% caused flexure strength to decrease by 25.3% at a replacement level of 25% EPS. However, the reduction percentage strongly depends upon the replacement level of EPS granules. Moreover, the lower strength concretes showed a higher water absorption values compared to higher strength concrete, i.e., increasing the volume percentage of EPS increases the water absorption as well as the negative strain (shrinkage). The negative strain was higher at concretes of lower density (containing a high amount of EPS aggregate). The water to cement ratio of EPS aggregate concrete is found to be slightly lower than that of conventional concrete.

Elsalah, Jamaleddin; Al-Sahli, Yosra; Akish, Ahmed; Saad, Omar; Hakemi, Abdurrahman

2013-12-01

283

Validation of phenol red versus gravimetric method for water reabsorption correction and study of gender differences in Doluisio's absorption technique.  

PubMed

The aim of the present study was to develop a method for water flux reabsorption measurement in Doluisio's Perfusion Technique based on the use of phenol red as a non-absorbable marker and to validate it by comparison with gravimetric procedure. The compounds selected for the study were metoprolol, atenolol, cimetidine and cefadroxil in order to include low, intermediate and high permeability drugs absorbed by passive diffusion and by carrier mediated mechanism. The intestinal permeabilities (Peff) of the drugs were obtained in male and female Wistar rats and calculated using both methods of water flux correction. The absorption rate coefficients of all the assayed compounds did not show statistically significant differences between male and female rats consequently all the individual values were combined to compare between reabsorption methods. The absorption rate coefficients and permeability values did not show statistically significant differences between the two strategies of concentration correction. The apparent zero order water absorption coefficients were also similar in both correction procedures. In conclusion gravimetric and phenol red method for water reabsorption correction are accurate and interchangeable for permeability estimation in closed loop perfusion method. PMID:24887261

Tu?cu-Demiröz, Fatmanur; Gonzalez-Alvarez, Isabel; Gonzalez-Alvarez, Marta; Bermejo, Marival

2014-10-01

284

Pressurized water extraction of ?-glucan enriched fractions with bile acids-binding capacities obtained from edible mushrooms.  

PubMed

A pressurized water extraction (PWE) method was developed in order to extract ?-glucans with bile acids-binding capacities from cultivated mushrooms (Agaricus bisporus, Lentinula edodes, and Pleurotus ostreatus) to be used as supplements to design novel foods with hypocholesterolemic properties. Extraction yields were higher in individual than sequential extractions being the optimal extraction parameters: 200°C, 5 cycles of 5 min each at 10.3 MPa. The crude polysaccharide (PSC) fractions, isolated from the PWE extracts contained mainly ?-glucans (including chitooligosaccharides deriving from chitin hydrolysis), ?-glucans, and other PSCs (hetero-/proteo-glucans) depending on the extraction temperature and mushroom strain considered. The observed bile acids-binding capacities of some extracts were similar to a ?-glucan enriched fraction obtained from cereals. PMID:24399760

Palanisamy, Marimuthu; Aldars-García, Laila; Gil-Ramírez, Alicia; Ruiz-Rodríguez, Alejandro; Marín, Francisco R; Reglero, Guillermo; Soler-Rivas, Cristina

2014-01-01

285

WVR-GPS comparison measurements and calibration of the 20-32 GHz tropospheric water vapor absorption model.  

SciTech Connect

Collocated measurements of opacity (from water vapor radiometer brightness temperatures) and wet path delay (from ground-based tracking of global positioning satellites) are used to constrain the model of atmospheric water vapor absorption in the 20-32 GHz band. A differential approach is presented in which the slope of opacity-versus-wet delay data is used as the absorption model constraint. This technique minimizes the effects of radiometric calibration errors and oxygen model uncertainties in the derivation of a best-fit vapor absorption model. A total of approximately five months of data was obtained from two experiment sites. At the Cloud and Radiation Testbed (CART) site near Lamont, Oklahoma, three independent water vapor radiometers (WVRs) provided near-continuous opacity measurements over the interval July-September 1998. At the NASA/Goldstone tracking station in the California desert two WVRs; obtained opacity data over the September-October 1997 interval. At both sites a Global Positioning Satellite (GPS) receiver and surface barometer obtained the data required for deriving the zenith wet delays over the same time frames. Measured values of the opacity-versus-wet delay slope parameter were obtained at four WVR frequencies (20.7, 22.2, 23.8, and 31.4 GHz) and compared with predictions of four candidate absorption models referenced in the literature. With one exception, all three models provide agreement within 5% of the opacity-versus-wet delay slope measurements at all WVR frequencies at both sites. One model provides agreement for all channels at both sites to the 2-3% level. This absorption model accuracy level represents a significant improvement over that attainable using radiosondes.

Keihm, S. J.; Bar-Server, Y.; Liljegren, J. C.; Environmental Research; NASA

2002-06-01

286

Role of glucose transporters in the intestinal absorption of gastrodin, a highly water-soluble drug with good oral bioavailability.  

PubMed

Gastrodin, a sedative drug, is a highly water-soluble phenolic glucoside with poor liposolubility but exhibits good oral bioavailability. The current study aims to investigate whether glucose transporters (GLTs) are involved in the intestinal absorption of gastrodin. The intestinal absorption kinetics of gastrodin was determined using the rat everted gut sac model, the Caco-2 cell culture model and the perfused rat intestinal model. In vivo pharmacokinetic studies using diabetic rats with high GLT expression were performed. Saturable intestinal absorption of gastrodin was observed in rat everted gut sacs. The apparent permeability (Papp) of gastrodin from the apical (A) to basolateral (B) side in Caco-2 cells was two-fold higher than that from B to A. Glucose or phlorizin, a sodium-dependent GLT (SGLT) inhibitor, reduced the absorption rates of gastrodin from perfused rat intestines. In vivo pharmacokinetic studies showed that the time of maximum plasma gastrodin concentration (Tmax) was prolonged from 28 to 72 min when orally co-administered with four times higher dose of glucose. However, the Tmax of gastrodin in diabetic rats was significantly lowered to 20 min because of the high intestinal SGLT1 level. In conclusion, our findings indicate that SGLT1 can facilitate the intestinal absorption of gastrodin. PMID:23480725

Cai, Zheng; Huang, Juan; Luo, Hui; Lei, Xiaolu; Yang, Zhaoxiang; Mai, Yang; Liu, Zhongqiu

2013-07-01

287

The role of skin absorption as a route of exposure for volatile organic compounds (VOCs) in drinking water.  

PubMed Central

Assessments of drinking water safety rely on the assumption that ingestion represents the principal route of exposure. A review of the experimental literature revealed that skin penetration rates for solvents are remarkably high, and that the stratum corneum is a less effective barrier to penetration than traditionally assumed. Based on published skin absorption rates, we used Fick's law (Jos = Kop delta Cos) to determine permeability constants for selected compounds. We then calculated dose per kilogram for nine different exposure situations and compared this to the oral dose per kilogram. We found that skin absorption contributed from 29-91 per cent of the total dose, averaging 64 per cent. Dose per kilogram body weight ranged from .0002 mg/kg-.18 mg/kg, with an average of .03 mg/kg. In weak aqueous solutions, flux of the solute is directly proportional to concentration. Laboratory approaches differ markedly from environmental exposures and can underestimate absorption. We conclude that skin absorption of contaminants in drinking water has been underestimated and that ingestion may not constitute the sole or even primary route of exposure. PMID:6711723

Brown, H S; Bishop, D R; Rowan, C A

1984-01-01

288

The choice of models relating tritiated water absorption to subepithelial blood flow in the rumen of sheep.  

PubMed Central

1. The blood flow to the ruminoreticulum of anaesthetized sheep was varied by changing the proportion of CO2 in the gas stirring solutions confined to this organ. 2. Clearance of tritiated water was thereby varied fourfold, from 10 to 44ml./min.100 g epithelium, with negligible net water movement. 4. Subepithelial blood flow, observed with radioactive microspheres using the reference organ technique, varied tenfold, from 20 to 200 ml./min.100 g epithelium. 4. The relation between tritiated water absorption and blood water flow was approximated by a hyperbolic model, but was appreciably better described using a higher order term in blood flow consistent with a countercurrent exchange of tritiated water between arterioles and venules. 5. The distribution of blood flow between different regions of the organ and between epithelium and muscle is described. PMID:536905

Dobson, A

1979-01-01

289

Radiation effects in water ice: A near-edge x-ray absorption fine structure study  

SciTech Connect

The changes in the structure and composition of vapor-deposited ice films irradiated at 20 K with soft x-ray photons (3-900 eV) and their subsequent evolution with temperatures between 20 and 150 K have been investigated by near-edge x-ray absorption fine structure spectroscopy (NEXAFS) at the oxygen K edge. We observe the hydroxyl OH, the atomic oxygen O, and the hydroperoxyl HO{sub 2} radicals, as well as the oxygen O{sub 2} and hydrogen peroxide H{sub 2}O{sub 2} molecules in irradiated porous amorphous solid water (p-ASW) and crystalline (I{sub cryst}) ice films. The evolution of their concentrations with the temperature indicates that HO{sub 2}, O{sub 2}, and H{sub 2}O{sub 2} result from a simple step reaction fuelled by OH, where O{sub 2} is a product of HO{sub 2} and HO{sub 2} a product of H{sub 2}O{sub 2}. The local order of ice is also modified, whatever the initial structure is. The crystalline ice I{sub cryst} becomes amorphous. The high-density amorphous phase (I{sub a}h) of ice is observed after irradiation of the p-ASW film, whose initial structure is the normal low-density form of the amorphous ice (I{sub a}l). The phase I{sub a}h is thus peculiar to irradiated ice and does not exist in the as-deposited ice films. A new 'very high density' amorphous phase--we call I{sub a}vh--is obtained after warming at 50 K the irradiated p-ASW ice. This phase is stable up to 90 K and partially transforms into crystalline ice at 150 K.

Laffon, C.; Lacombe, S.; Bournel, F.; Parent, Ph. [Laboratoire de Chimie-Physique, Matiere et Rayonnement, UMR 7614, Universite Pierre et Marie Curie et CNRS, 11 Rue Pierre et Marie Curie, 75231 Paris, Cedex 05 (France); Laboratoire des Collisions Atomiques et Moleculaires, UMR 8625, Universite Paris Sud 11, 91405 Orsay Cedex (France); Laboratoire de Chimie-Physique, Matiere et Rayonnement, UMR 7614, Universite Pierre et Marie Curie et CNRS, 11 Rue Pierre et Marie Curie, 75231 Paris, Cedex 05 (France)

2006-11-28

290

An application of water recreation capacity standards to reservoir development planning  

E-print Network

IV. A Survey of Current Mater Use Capacity Standards 12 Federal U'e of Standards 14 State Use of Standards County Use of Standards Standards Formu]ation Current Standards 16 17 22 V. Survey of the Lake Livingston Reservoir Site 37 General... Development 65 Mater Use Fianagement 72 Recomm ndation Implementation VIII. Summary Literature Cited LIST 01" TABLES Table 1. Summary of Standards Survey Responses 2. Smmaary of Agency Methods of Standards Formulation Page 13 19 3. Summary...

Petersen, Grant Arthur

2012-06-07

291

Hydroxytyrosol, as a component of olive mill waste water, is dose- dependently absorbed and increases the antioxidant capacity of rat plasma.  

PubMed

Hydroxytyrosol is the most potent phenolic antioxidant of olive oil and olive mill waste water (OMWW) and its biological activities have stimulated research on its potential role in cardiovascular protection. However, evidence of the absorption of OMWW phenolics and on their possible in vivo activity has, until now, never been provided. Three groups male Sprague-Dawley rats were administered 1, 5, or 10 mg/Kg of the OMWW extract, respectively, providing 41.4, 207, and 414 microg/Kg of hydroxytyrosol, respectively. Urine was collected for 24 h and the urinary levels of hydroxytyrosol were quantified by mass spectrometry. Hydroxytyrosol was dose-dependently (R(2) = 0.95) absorbed and excreted in the urines mostly as a glucuronide conjugate. Further, the administration of an hydroxytyrosol-rich OMWW extract (10 mg/kg) to the rats was also associated with an increase of their plasma antioxidant capacity. Future experiments will eventually further clarify its metabolic fate and its in vivo actions. PMID:11264904

Visioli, F; Caruso, D; Plasmati, E; Patelli, R; Mulinacci, N; Romani, A; Galli, G; Galli, C

2001-03-01

292

Water vapor differential absorption lidar measurements using a diode-pumped all-solid-state laser at 935 nm  

Microsoft Academic Search

A diode-pumped, single-frequency laser system emitting at 935 nm has recently been developed to serve as the transmitter for\\u000a water vapor differential absorption lidar (DIAL) measurements. This laser uses Nd:YGG (Y3Ga5O12) as the active medium and emits radiation directly at 935 nm without the need of additional frequency conversion processes.\\u000a The system was diode-pumped at 806 nm and was built up in

A. Fix; G. Ehret; J. Löhring; D. Hoffmann; M. Alpers

2011-01-01

293

A diode-pumped Cr:LiSAF laser for UAV-based water vapor differential absorption lidar (DIAL)  

Microsoft Academic Search

An autonomous, compact, high-energy, injection seeded, diode-pumped, tunable Cr:LiSAF laser for a water vapor differential absorption lidar (DIAL) system deployed on a high-altitude unpiloted airborne vehicle (UAV) has been developed. A unique laser resonator, consisting of a Cr:LiSAF slab pumped by 8 high-power diode bar stacks in a total internal reflection configuration, provides high extraction efficiency and good laser beam

Coorg R. Prasad; Viktor A. Fromzel; Joseph S. Smucz; In H. Hwang; William E. Hasselbrack

2000-01-01

294

Application of Temperature-Dependent Fluorescent Dyes to the Measurement of Millimeter Wave Absorption in Water Applied to Biomedical Experiments  

PubMed Central

Temperature sensitivity of the fluorescence intensity of the organic dyes solutions was used for noncontact measurement of the electromagnetic millimeter wave absorption in water. By using two different dyes with opposite temperature effects, local temperature increase in the capillary that is placed inside a rectangular waveguide in which millimeter waves propagate was defined. The application of this noncontact temperature sensing is a simple and novel method to detect temperature change in small biological objects. PMID:25435859

Popenko, Oleksandr

2014-01-01

295

Simultaneous Determination of Trace Heavy Metals in Waters by Atomic Absorption Spectrometry After Preconcentration by Solvent Extraction  

Microsoft Academic Search

A simple and rapid method for the simultaneous extraction of heavy metals using a new reagent 5-(2?-carbomethoxyphenyl; azo-8-quinolinol(R) into methyl isobutyl. ketone (MIBK) and their subsequent determination by flame atomic absorption spectrometry is described. The method has been applied to the determination of Cu. Pb, Ni, Fe, Cr, Co and Mo in drinking and bore well waters. The extraction has

R. Saran; T. S. Basu Baul; P. Srinivas; D. T. Khathing

1992-01-01

296

Application of temperature-dependent fluorescent dyes to the measurement of millimeter wave absorption in water applied to biomedical experiments.  

PubMed

Temperature sensitivity of the fluorescence intensity of the organic dyes solutions was used for noncontact measurement of the electromagnetic millimeter wave absorption in water. By using two different dyes with opposite temperature effects, local temperature increase in the capillary that is placed inside a rectangular waveguide in which millimeter waves propagate was defined. The application of this noncontact temperature sensing is a simple and novel method to detect temperature change in small biological objects. PMID:25435859

Kuzkova, Nataliia; Popenko, Oleksandr; Yakunov, Andrey

2014-01-01

297

Development of a practical model for capacity evaluation of ultrapure water systems  

Microsoft Academic Search

Modern ultrapure water (UPW) systems designed for the semiconductor manufacturing industry are very complex nowadays, especially when wastewater recycling is part of the configuration. In this paper, we developed a practical model for system evaluation by correlating the actual UPW consumption rate, TI, with the velocity of water level changes (?) in the storage tank. It was found that the

Ming Wu; Darren Sun; Joo Hwa Tay

2004-01-01

298

INTEGRATION OF HEAT CAPACITY AND ELECTRICAL CONDUCTIVITY SENSORS FOR ROOT MODULE WATER AND NUTRIENT ASSESSMENT  

Technology Transfer Automated Retrieval System (TEKTRAN)

Management of water content and nutrient status during space flight is a critical necessity in plant production systems. Our objectives were to determine if dual-probe heat pulse sensors could improve water content determination accuracy over single-probe heat-pulse sensors, and to test a design usi...

299

Possibilistic approach for consideration of uncertainties to estimate structural capacity of ageing cast iron water mains  

Microsoft Academic Search

Drinking water distribution networks form essential components of all urban centres. Water mains buried in the soil-backfill are exposed to different deleterious reactions, with the result being that the design factor of safety may significantly degrade, leading to structural failure. In particular, metallic distribution and trunk mains are subject to cor- rosion. Proactive pipeline management, which entails timely maintenance, repair,

Solomon Tesfamariam; Balvant Rajani; Rehan Sadiq

2006-01-01

300

Spring carbonate chemistry dynamics of surface waters in the northern East China Sea: Water mixing, biological uptake of CO2, and chemical buffering capacity  

NASA Astrophysics Data System (ADS)

investigated sea surface total alkalinity (TAlk), dissolved inorganic carbon (DIC), dissolved oxygen (DO), and satellite-derived chlorophyll-a in the connection between the Yellow Sea and the East China Sea (ECS) during April to early May 2007. In spring, Changjiang dilution water (CDW), ECS offshore water, and together with Yellow Sea water (YSW) occupied the northern ECS. Using 16 day composite satellite-derived chlorophyll-a images, several algal blooms were identified in the CDW and ECS offshore water. Correspondingly, biological DIC drawdown of 73 ± 20 ?mol kg-1, oversaturated DO of 10-110 ?mol O2 kg-1, and low fugacity of CO2 of 181-304 ?atm were revealed in these two waters. YSW also showed CO2 uptake in spring, due to the very low temperature. However, its intrusion virtually counteracted CO2 uptake in the northern ECS. In the CDW and the ECS offshore water, Revelle factor was 9.3-11.7 and 8.9-10.6, respectively, while relatively high Revelle factor values of 11.4-13.0 were revealed in YSW. In the ECS offshore water, the observed relationship between DIC drawdown and oversaturated DO departed from the Redfield ratio, indicating an effect of chemical buffering capacity on the carbonate system during air-sea reequilibration. Given the fact that the chemical buffering capacity slows down the air-sea reequilibration of CO2, the early spring DIC drawdown may have durative effects on the sea surface carbonate system until early summer. Although our study is subject to limited temporal and spatial coverage of sampling, these insights are fundamental to understanding sea surface carbonate chemistry dynamics in this important ocean margin.

Zhai, Wei-Dong; Chen, Jian-Fang; Jin, Hai-Yan; Li, Hong-Liang; Liu, Jin-Wen; He, Xian-Qiang; Bai, Yan

2014-09-01

301

Water vapor absorption in porous media polluted by calcium nitrate studied by time domain nuclear magnetic resonance.  

PubMed

Nuclear magnetic resonance relaxation analysis of liquid water (1)H nuclei in real porous media, selected for their similar composition (carbonate rocks) and different pore space architecture, polluted with calcium nitrate, is presented to study the kinetics of water condensation and salt deliquescence inside the pore space. These phenomena are responsible for deterioration of porous materials when exposed to environmental injury by pollution in a humid atmosphere. The theory is well described for simple pore geometries, but it is not yet well understood in real porous media with wide distributions of pore sizes and connections. The experiment is performed by following in time the formation of liquid water inside the pore space by T(1) and T(2) relaxation time distributions. The distributions allow one to see the effects of both the salt concentration and the pore space structure on the amount of water vapor condensed and its kinetics. It is shown that, for a given lithotype, even with different amounts of pollutant, the rate-average relaxation time T(1ra) tends to increase monotonically with NMR signal, proportional to the amount of liquid water. T(1ra) is often inversely associated with surface-to-volume ratio. This suggests a trend toward the filling of larger pores as amounts of liquid water increase, but it does not indicate a strict sequential filling of pores in order of size and starting with the smallest; in fact, relaxation time distributions show clearly that this is not the case. Increased amounts of salt lead to both markedly increased rates and markedly increased amounts of water absorption. NMR measurements of amounts of water, together with relaxation time distributions, give the possibility of information on the effect of pollution in porous materials exposed to humid atmospheres but sheltered from liquid water, even before the absorption of large amounts of moisture and subsequent damage. These phenomena are of importance also in other fields, such as the exploitation of geothermal energy. PMID:19594125

Gombia, Mirko; Bortolotti, Villiam; Brown, Robert J S; Camaiti, Mara; Cavallero, Luisa; Fantazzini, Paola

2009-08-01

302

Graphite furnace atomic absorption spectrometric detection of vanadium in water and food samples after solid phase extraction on multiwalled carbon nanotubes.  

PubMed

Vanadium(V) ions as 8-hydroxyquinoline chelates were loaded on multiwalled carbon nanotubes (MWNTs) in a mini chromatographic column. Vanadium was determined by graphite furnace atomic absorption spectrometry (GFAAS). Various analytical parameters including pH of the working solutions, amounts of 8-hydroxyquinoline, eluent type, sample volume, and flow rates were investigated. The effects of matrix ions and some transition metals were also studied. The column can be reused 250 times without any loss in its sorption properties. The preconcentration factor was found as 100. Detection limit (3 s) and limit of quantification (10 s) for the vanadium in the optimal conditions were observed to be 0.012 µg L(-1) and 0.040 ?g L(-1), respectively. The capacity of adsorption was 9.6 mg g(-1). Relative standard deviation (RSD) was found to be 5%. The validation of the method was confirmed by using NIST SRM 1515 Apple leaves, NIST SRM 1570a Spinach leaves and GBW 07605 Tea certified reference materials. The procedure was applied to the determination of vanadium in tap water and bottled drinking water samples. The procedure was also successfully applied to microwave digested food samples including black tea, coffee, tomato, cabbage, zucchini, apple and chicken samples. PMID:24148394

Wadhwa, Sham Kumar; Tuzen, Mustafa; Gul Kazi, Tasneem; Soylak, Mustafa

2013-11-15

303

BELINDA: Broadband Emission Lidar with Narrowband Determination of Absorption. A new concept for measuring water vapor and temperature profiles  

NASA Technical Reports Server (NTRS)

We present a new concept for differential absorption lidar measurements of water vapor and temperature profiles. The idea is to use one broadband emission laser and a narrowband filter system for separation of the 'online' and 'offline' return signals. It is shown that BELINDA offers improvements as to laser emission shape and stability requirements, background suppression, and last and most important a significant reduction of the influence of Rayleigh scattering. A suitably designed system based on this concept is presented, capable of measuring water vapor or temperature profiles throughout the planetary boundary layer.

Theopold, F. A.; Weitkamp, C.; Michaelis, W.

1992-01-01

304

BELINDA: Broadband Emission Lidar with Narrowband Determination of Absorption. A new concept for measuring water vapor and temperature profiles  

NASA Astrophysics Data System (ADS)

We present a new concept for differential absorption lidar measurements of water vapor and temperature profiles. The idea is to use one broadband emission laser and a narrowband filter system for separation of the 'online' and 'offline' return signals. It is shown that BELINDA offers improvements as to laser emission shape and stability requirements, background suppression, and last and most important a significant reduction of the influence of Rayleigh scattering. A suitably designed system based on this concept is presented, capable of measuring water vapor or temperature profiles throughout the planetary boundary layer.

Theopold, F. A.; Weitkamp, C.; Michaelis, W.

1992-07-01

305

Chloride and water secretion and absorption by the gills of the eel  

Microsoft Academic Search

Perfusion experiments with the heart-gill preparation of the common eel, Anguilla vulgaris, are presented. Various concentrations of perfusion medium were used with eels from both sea water and fresh water. The external medium was sea water in the case of the sea water eels and fresh water in the other case.

Ancel B. Keys

1931-01-01

306

The self-cleaning capacity of surface waters after radioactive fallout. Evidence from European waters after Chernobyl, 1986-1988  

Microsoft Academic Search

Radionuclide fallout from the burning Chernobyl reactor provided a pulsed input of ¹³⁷Cs to surface waters and watersheds of Europe. Radionuclide analyses of surface waters indicated that initial rates of decrease of ¹³⁷Cs concentrations in contaminated rivers were on the order of 0.125 day⁻¹, which was found to be consistent with the size of the mobile inventory in the watersheds

Peter H. Santschi; S. Bollhalder; S. Zingg; A. Lueck; K. Farrenkothen

1990-01-01

307

Assessment of capacity sensors for monitoring soil water content in ecological orchards  

NASA Astrophysics Data System (ADS)

Water is an important element for soil tillage and crop development. Its proper management is essential for the development of plants, by preventing excess or shortage in water application. Soil water content is affected by the soil-water-plant system and its monitoring is a required within a sustainable agriculture framework respectful with the natural environment. Thus, the aim of this study was to evaluate the performance of capacitive sensors in monitoring soil moisture from organic orchards. An experimental text was carried out at the Hydraulics Laboratory of the Agricultural Engineering School in the Polytechnic University of Madrid (Spain). Soil samples were collected within the 0-20 cm depth layers from the university organic orchard. The samples were air dried and subsequently sieved in a 2 mm mesh sieve, removing roots and coarse fractions and keeping the fine soil. The amount of fine soil was calculated from the soil density and the soil samples were compacted to obtain the relative volume that corresponded to their density. The measurements were carried out in dry and in saturated soil and, also in samples where soil was stirring with: 150 cm³, 300 cm³ and 450 cm³ of water. A 1890 ml container was used to hold the fine soil and the soil moisture sensor ECH2O, type 10 HS (Decagon Devices, Inc.) was placed horizontally at 5 cm depth. Soil water readings were recorded on a datalogger Em5b from the same manufacturer. The results showed that the capacitive sensor has a linear response to soil moisture content. Its value was overestimated in comparison to the volumetric values and the largest errors (about 8%) were observed in the soils with high moisture contents. Overall, these results point out that the ECH2O sensor, model 10 HS, could determine with sufficient accuracy the volumetric soil water content from organic orchards although it could be further improved by "in situ" calibration.

Patrícia Prazeres Marques, Karina; Horcajo, Daniel; Rodriguez-Sinobas, Leonor

2014-05-01

308

Bicarbonate secretion plays a role in chloride and water absorption of the European flounder intestine.  

PubMed

Experiments performed on isolated intestinal segments from the marine teleost fish, the European flounder (Platichthys flesus), revealed that the intestinal epithelium is capable of secondary active HCO3(-) secretion in the order of 0.2-0.3 micromol x cm(-2) x h(-1) against apparent electrochemical gradient. The HCO3(-) secretion occurs via anion exchange, is dependent on mucosal Cl(-), results in very high mucosal HCO3(-) concentrations, and contributes significantly to Cl(-) and fluid absorption. This present study was conducted under in vivo-like conditions, with mucosal saline resembling intestinal fluids in vivo. These conditions result in a transepithelial potential of -16.2 mV (serosal side negative), which is very different from the -2.2 mV observed under symmetrical conditions. Under these conditions, we found a significant part of the HCO3(-) secretion is fueled by endogenous epithelial CO2 hydration mediated by carbonic anhydrase because acetazolamide (10(-4) M) was found to inhibit HCO3(-) secretion and removal of serosal CO(2) was found not to influence HCO3(-) secretion. Reversal of the epithelial electrochemical gradient for Cl(-) (removal of serosal Cl(-)) and elevation of serosal HCO3(-) resulted in enhanced HCO3(-) secretion and enhanced Cl(-) and fluid absorption. Cl(-) absorption via an anion exchange system appears to partly drive fluid absorption across the intestine in the absence of net Na(+) absorption. PMID:15576660

Grosell, M; Wood, C M; Wilson, R W; Bury, N R; Hogstrand, C; Rankin, C; Jensen, F B

2005-04-01

309

Institutional Capacity on Water Pollution Control of the Pearl River in Guangzhou, China  

Microsoft Academic Search

This paper analyzes the role of the prevalent formal and informal institutions in Guangzhou in alleviating deteriorating water quality in the Pearl River. In addition to the dominating role of the local government, it examines the influences of other relevant factors such as the role of environmental non-governmental organizations, the media, and the impact of social and cultural norms. It

Yuan Yu; Dieudonné-Guy Ohandja; J. Nigel B. Bell

2012-01-01

310

A Simple Approach for Demonstrating Soil Water Retention and Field Capacity  

ERIC Educational Resources Information Center

It is difficult to demonstrate the soil water retention relationship and related concepts because the specialized equipment required for performing these measurements is unavailable in most classrooms. This article outlines a low-cost, easily visualized method by which these concepts can be demonstrated in most any classroom. Columns (62.5 cm…

Howard, A.; Heitman, J. L.; Bowman, D.

2010-01-01

311

Design, Fabrication, and Testing of High Capacity High-Temperature Monel\\/Water Heat Pipes  

Microsoft Academic Search

A development program was completed to demonstrate key technologies required for the JIMO Heat Pipe Radiator. Part of this work included the design, assembly, and performance testing of two favorable wick designs in full length water heat pipes. A parametric study identified CP-2 titanium and Monel K-500 alloys as favorable envelope materials. The design effort also identified two promising wick

John H. Rosenfeld; Bruce L. Drolen; Cheng-Yi Lu

2006-01-01

312

INCREASING THE PHOSPHORUS SORPTION CAPACITY OF SOUTHEASTERN COASTAL PLAIN SOILS USING WATER TREATMENT RESIDUALS  

Microsoft Academic Search

Long-term animal manure applications to many sandy Coastal Plain soils has resulted in the accumulation of excess soil phosphorus (P). When soils contain excessive P concentrations, dissolved phosphorus (DP) can be des- orbed with water and transported into streams and rivers via runoff and leaching. The addition of DP into nutrient-sensitive Coastal aquatic ecosys- tems can then stimulate aquatic weed

J. M. Novak; D. W. Watts

2004-01-01

313

Morphological correlate of regional partitioning of integumental water absorption in terrestrial slugs.  

PubMed

An ultrastructural study of the foot surface of the terrestrial mollusc, Limax maximus, has revealed a correlation of epithelial cell type with the functional partitioning of the surface. The lateral absorptive bands of the foot are comprised exclusively of microvillar epithelial cells, while those of the medial locomotor band are all ciliated. Thus, there is a clear partitioning of epithelial cell types between areas of the foot surface with distinct functional roles. Consistent with the proposed role for paracellular absorption, varying states of hydration are shown to affect the extent of the intercellular spaces, but not the intracellular architecture. PMID:8073419

Prior, D J; Maugel, T K; Sellers, M

1994-06-01

314

Very high finesse optical-feedback cavity-enhanced absorption spectrometer for low concentration water vapor isotope analyses.  

PubMed

So far, cavity-enhanced absorption spectroscopy (CEAS) has been based on optical cavities with a high finesse F that, however, has been limited by mirror reflectivity and by cavity transmission considerations to a few times 10,000. Here, we demonstrate a compact near-infrared optical-feedback CEAS instrument for water vapor isotope ratio measurements, with F>140,000. We show that this very high finesse can be effectively exploited to improve the detection sensitivity to the full extent predicted by the increased effective path length to reach a noise equivalent absorption sensitivity of 5.7×10(-11)??cm(-1)?Hz(-1/2) for a full spectrum registration (including possible effects of interference fringes and fit model inadequacies). PMID:24686607

Landsberg, J; Romanini, D; Kerstel, E

2014-04-01

315

Determination of trace silver in water samples by online column preconcentration flame atomic absorption spectrometry using termite digestion product.  

PubMed

A new method for Ag determination in water samples using solid phase extraction (SPE) coupled to a flow injection system and flame atomic absorption spectrometry was developed. The sorbent used for Ag preconcentration and extraction was the termite digestion product. Flow and chemical variables of the system were optimized through a multivariate procedure. The factors selected were adsorbent mass, buffer type and concentration, sample pH, and sample flow rate. The detection limit and precision were 3.4??g?L(-1) and 3.8% (n = 6, 15??g?L(-1)), respectively. The enrichment factor and the linear working range were, respectively, 21 and 10-50??g?L(-1). Results for recovery tests using different water samples were between 96 and 107%. The proposed methodology was applied with success for the determination of Ag in water used to wash clothes impregnated with silver nanoparticles, supplied by a factory located in Santa Catarina, Brazil. PMID:21804766

Bianchin, Joyce Nunes; Martendal, Edmar; Carasek, Eduardo

2011-01-01

316

Determination of Trace Silver in Water Samples by Online Column Preconcentration Flame Atomic Absorption Spectrometry Using Termite Digestion Product  

PubMed Central

A new method for Ag determination in water samples using solid phase extraction (SPE) coupled to a flow injection system and flame atomic absorption spectrometry was developed. The sorbent used for Ag preconcentration and extraction was the termite digestion product. Flow and chemical variables of the system were optimized through a multivariate procedure. The factors selected were adsorbent mass, buffer type and concentration, sample pH, and sample flow rate. The detection limit and precision were 3.4??g?L?1 and 3.8% (n = 6, 15??g?L?1), respectively. The enrichment factor and the linear working range were, respectively, 21 and 10–50??g?L?1. Results for recovery tests using different water samples were between 96 and 107%. The proposed methodology was applied with success for the determination of Ag in water used to wash clothes impregnated with silver nanoparticles, supplied by a factory located in Santa Catarina, Brazil. PMID:21804766

Bianchin, Joyce Nunes; Martendal, Edmar; Carasek, Eduardo

2011-01-01

317

Visible Absorption Spectrum of Chlorophyll a, b, and beta-Carotene Molecules mixed in Monolayers at a Water-Air Interface  

Microsoft Academic Search

IN a previous communication1, visible absorption spectra of chlorophyll a or b in monolayers were compared with those taken in several organic solvents. The red and blue absorption peaks of the chlorophylls in monolayers at water-air and water-oil interfaces were found to be shifted towards longer wavelengths as compared with their solution peaks. This shift was postulated to be possibly

Germille Colmano

1962-01-01

318

Water Channel of Horseradish Peroxidase Studied by the Charge-Transfer Absorption Band of Ferric Heme  

E-print Network

connects the aqueous solution to the heme site. Ferric horseradish peroxidase has an absorption band at 640, it seems likely that the CT band will be sensitive to the hydration of the protein. To study this premise, the protein was incorporated into trehalose/sucrose glasses and the hydration of the sugar glasses was varied

Sharp, Kim

319

Globalland30 Mapping Capacity of Land Surface Water in Thessaly, Greece  

NASA Astrophysics Data System (ADS)

The National Geomatics Center of China (NGCC) produced Global Land Cover (GlobalLand30) maps with 30 m spatial resolution for the years 2000 and 2009-2010, responding to the need for harmonized, accurate, and high-resolution global land cover data. This study aims to assess the mapping accuracy of the land surface water layer of GlobalLand30 for 2009-2010. A representative Mediterranean region, situated in Greece, is considered as the case study area, with 2009 as the reference year. The assessment is realized through an object-based comparison of the GlobalLand30 water layer with the ground truth and visually interpreted data from the Hellenic Cadastre fine spatial resolution (0.5 m) orthophoto map layer. GlobCover 2009, GlobCorine 2009, and GLCNMO 2008 corresponding thematic layers are utilized to show and quantify the progress brought along with the increment of the spatial resolution, from 500 m to 300 m and finally to 30 m with the newly produced GlobalLand30 maps. GlobalLand30 detected land surface water areas show a 91.9% overlap with the reference data, while the coarser resolution products are restricted to lower accuracies. Validation is extended to the drainage network elements, i.e., rivers and streams, where GlobalLand30 outperforms the other global map products, as well.

Manakos, Ioannis; Chatzopoulos-Vouzoglanis, Konstantinos; Petrou, Zisis I.; Filchev, Lachezar; Apostolakis, Antonis

2015-01-01

320

BREATH MEASUREMENT AND MODELS TO ASSESS VOC DERMAL ABSORPTION IN WATER  

EPA Science Inventory

Dermal exposure to volatile organic compounds (VOCs) in water results from environmental contamination of surface, ground-, and drinking waters. This exposure occurs both in occupational and residential settings. Compartmental models incorporating body burden measurements have ...

321

Emission, absorption and group delay of microwaves in the atmosphere in relation to water vapour content over the Indian subcontinent  

NASA Technical Reports Server (NTRS)

The advent of satellite communication for global coverage has apparently indicated a renewed interest in the studies of radio wave propagation through the atmosphere, in the VHF, UHF and microwave bands. The extensive measurements of atmosphere constituents, dynamics and radio meterological parameters during the Middle Atmosphere Program (MAP) have opened up further the possibilities of studying tropospheric radio wave propagation parameters, relevant to Earth/space link design. The three basic parameters of significance to radio propagation are thermal emission, absorption and group delay of the atmosphere, all of which are controlled largely by the water vapor content in the atmosphere, particular at microwave bands. As good emitters are also good absorbers, the atmospheric emission as well as the absorption attains a maximum at the frequency of 22.235 GHz, which is the peak of the water vapor line. The group delay is practically independent of frequency in the VHF, UHF and microwave bands. However, all three parameters exhibit a similar seasonal dependence originating presumably from the seasonal dependence of the water vapor content. Some of the interesting results obtained from analyses of radiosonde data over the Indian subcontinent collected by the India Meteorological Department is presented.

Sen, A. K.; Gupta, A. K. D.; Karmakar, P. K.; Barman, S. D.; Bhattacharya, A. B.; Purkait, N.; Gupta, M. K. D.; Sehra, J. S.

1985-01-01

322

Vitamin enhanced waters and polyphenol rich beverages analyzed for antioxidant capacity and antioxidants/calorie.  

PubMed

The purpose of this study was to analyze polyphenol rich beverages (vitamin enhanced waters (VEWs), fruit juices and berry juices) to determine free polyphenol concentrations and free polyphenols per Calorie based on a serving size. The Folin-Ciocalteu reagent was used in a colorimetric assay based on a catechin standard. Fruit and berry juices contained, on average, more than eight-times the concentration of free polyphenols when compared to VEWs. When Calories per serving were taken into consideration, fruit and berry juices contained more than twice the free polyphenols per Calorie. PMID:22254009

Donnelly, Patrick E; Churilla, Thomas M; Coco, Michael G; Vinson, Joe A

2010-12-01

323

Soluplus-coated colloidal silica nanomatrix system for enhanced supersaturation and oral absorption of poorly water-soluble drugs.  

PubMed

In this study, a Soluplus-coated colloidal silica nanomatrix (SCCSN) formulation for the entrapment of poorly water-soluble drugs was devised. The maximum supersaturation of the drug-loaded nanomatrix was higher than that of a physical mixture as indicated by the results of in vitro kinetic solubility studies. For atorvastatin calcium, dutasteride, and sorafenib tosylate, there were 2.8-, 326-, and 46.4-fold increases in solubility, respectively. For dutasteride, a promising 4.7-fold increase for in vivo oral drug absorption in the entrapped nanomatrix was observed as compared to the free physical mixture, supported by statistical significance testing of pharmacokinetic parameters. PMID:23336707

Kim, Min-Soo

2013-12-01

324

X-ray absorption spectrum for guanosine- 5'-monophosphate in water solution in the vicinity of the nitrogen K-edge observed in free liquid jet in vacuum  

NASA Astrophysics Data System (ADS)

A new spectroscopy for direct effect of radiation damage to nucleic acids such as DNA and RNA is underway using a liquid beam sample in vacuum combined with soft-X-ray synchrotron radiation. We show the X-ray absorption spectrum (XANES) of liquid phase water at X-ray photon energy in the vicinity of oxygen K-shell absorption edge obtained from total photoelectron yields ejected from a pure water beam. We confirm a "liquid sample in vacuum" for the present experiment by the measurements of the temperature dependence of the XANES spectrum for a liquid beam of pure water. Shown is the first measurement of the XANES spectrum for guanosine- 5'-monophosphate (GMP), which is one of the fundamental nucleotide unit for RNA, in water solution at X-ray photon energy in the vicinity of nitrogen K-shell absorption edge involved in the 'water-window' region, which corresponds to a selective excitation of guanine site.

Ukai, Masatoshi; Yokoya, Akinari; Fujii, Kentaro; Saitoh, Yuji

2008-10-01

325

WATER ABSORPTION IN GALACTIC TRANSLUCENT CLOUDS: CONDITIONS AND HISTORY OF THE GAS DERIVED FROM HERSCHEL /HIFI PRISMAS OBSERVATIONS  

SciTech Connect

We present Herschel/HIFI observations of the three ground state transitions of H{sub 2}O (556, 1669, and 1113 GHz) and H{sub 2}{sup 18}O (547, 1655, and 1101 GHz)-as well as the first few excited transitions of H{sub 2}O (987, 752, and 1661 GHz)-toward six high-mass star-forming regions, obtained as part of the PRISMAS (PRobing InterStellar Molecules with Absorption line Studies) Guaranteed Time Key Program. Water vapor associated with the translucent clouds in Galactic arms is detected in absorption along every line of sight in all the ground state transitions. The continuum sources all exhibit broad water features in emission in the excited and ground state transitions. Strong absorption features associated with the source are also observed at all frequencies except 752 GHz. We model the background continuum and line emission to infer the optical depth of each translucent cloud along the lines of sight. We derive the column density of H{sub 2}O or H{sub 2}{sup 18}O for the lower energy level of each transition observed. The total column density of water in translucent clouds is usually about a few 10{sup 13} cm{sup -2}. We find that the abundance of water relative to hydrogen nuclei is 1 Multiplication-Sign 10{sup -8} in agreement with models for oxygen chemistry in which high cosmic ray ionization rates are assumed. Relative to molecular hydrogen, the abundance of water is remarkably constant through the Galactic plane with X(H{sub 2}O) =5 Multiplication-Sign 10{sup -8}, which makes water a good traced of H{sub 2} in translucent clouds. Observations of the excited transitions of H{sub 2}O enable us to constrain the abundance of water in excited levels to be at most 15%, implying that the excitation temperature, T {sub ex}, in the ground state transitions is below 10 K. Further analysis of the column densities derived from the two ortho ground state transitions indicates that T {sub ex} {approx_equal} 5 K and that the density n(H{sub 2}) in the translucent clouds is below 10{sup 4} cm{sup -3}. We derive the water ortho-to-para ratio for each absorption feature along the line of sight and find that most of the clouds show ratios consistent with the value of 3 expected in thermodynamic equilibrium in the high-temperature limit. However, two clouds with large column densities exhibit a ratio that is significantly below 3. This may argue that the history of water molecules includes a cold phase, either when the molecules were formed on cold grains in the well-shielded, low-temperature regions of the clouds, or when they later become at least partially thermalized with the cold gas ({approx}25 K) in those regions; evidently, they have not yet fully thermalized with the warmer ({approx}50 K) translucent portions of the clouds.

Flagey, N.; Goldsmith, P. F. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)] [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Lis, D. C.; Monje, R.; Phillips, T. G. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)] [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Gerin, M.; De Luca, M.; Godard, B. [LERMA, UMR 8112 du CNRS, Observatoire de Paris, Ecole Normale Superieure, UPMC and UCP (France)] [LERMA, UMR 8112 du CNRS, Observatoire de Paris, Ecole Normale Superieure, UPMC and UCP (France); Neufeld, D. [Department of Physics and Astronomy, Johns Hopkins Univ. 3400 N. Charles St., Baltimore, MD 21218 (United States)] [Department of Physics and Astronomy, Johns Hopkins Univ. 3400 N. Charles St., Baltimore, MD 21218 (United States); Sonnentrucker, P. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)] [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Goicoechea, J. R., E-mail: nflagey@jpl.nasa.gov [Centro de Astrobiologia (CSIC-INTA), E-28850 Torrejon de Ardoz, Madrid (Spain)

2013-01-01

326

Using GPR and Soil EC to Identify Spatial Variability of Water Holding Capacity for Precision Irrigation Management  

NASA Astrophysics Data System (ADS)

Applying the appropriate amount of irrigation water is an especially critical part of irrigation management because both under and over irrigation can lead to reduced crop yield and loss of financial profit. Irrigation water soaks into and is stored in the soil moisture profile; the degree to which a soil can hold that moisture in the profile and prevent deep percolation is known as its water holding capacity (WHC). Because crops rely on the use of the water stored within the soil moisture profile, the WHC of the soil greatly influences the amount of applied irrigation water (AIW) required to optimize crop yield and resource management. Soil texture, which is a primary control of WHC, is known to vary spatially in many areas of agricultural production. Optimization of irrigation water use requires areas of different WHC to be irrigated differently; however, areas of differing WHC must be accurately identified for precision irrigation to be effective. Two methods were used on a research site known to contain soil texture variability to generate a geo-referenced map of soil texture differences in order to account for spatial WHC variability and optimize AIW. Ground penetrating radar (GPR) was used in conjunction with GPS and GIS systems to map the water content change found at the soil texture interfaces in the field. The second method was to produce a geo-referenced map of soil electrical conductivity (EC) using a Veris EC implement with similar GPS and GIS systems. The soil EC map is strongly related to soil texture and WHC under the consistent pH conditions that exist on the research site. The GPR and EC maps were then used to guide plot placement to block on soil WHC variation for a deficit irrigation study on upland cotton. The lint yield results from the irrigation study will provide insight into the effectiveness of the irrigation management zones identified by the two mapping methods. Lastly, soil cores will be taken from key areas identified in the GPR and EC results to ground-truth the readings and compare the accuracy of each mapping method.

Duncan, H. A.; Leib, B.

2011-12-01

327

Feasibility of tropospheric water vapor profiling using infrared heterodyne differential absorption lidar  

SciTech Connect

The development and verification of realistic climate model parameterizations for clouds and net radiation balance and the correction of other site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. In this study, we develop system performance models and examine the potential of infrared differential absoroption lidar (DIAL) to determine the concentration of water vapor.

Grund, C.J.; Hardesty, R.M. [National Oceanic and Atmospheric Administration Environmental Technology Laboratoy, Boulder, CO (United States); Rye, B.J. [Univ. of Colorado, Boulder, CO (United States)

1996-04-01

328

Correction scheme for spectral broadening by Rayleigh scattering in differential absorption lidar measurements of water vapor in the troposphere.  

PubMed

An evaluation scheme is given to calculate the water vapor content from data obtained by differential absorption lidar (DIAL), taking into account that the Rayleigh scattered part of the return signal shows considerable spectral broadening in contrast to the Mie scattered part. To correct for errors caused by this effect, information on the aerosol backscattering properties is necessary. Sensitivity analysis performed by model calculations show that it can be retrieved with sufficient accuracy from the off-line signal in the same way as for backscatter lidar. It can be expected that water vapor retrieval will be possible with good accuracy even in the most critical cases, where steep gradients in aerosol backscattering exist in the upper troposphere. PMID:20490005

Ansmann, A; Bosenberg, J

1987-08-01

329

Injection-seeded alexandrite ring laser: performance and application in a water-vapor differential absorption lidar.  

PubMed

A new laser system for use of differential absorption lidar (DIAL) in measurements of tropospheric water vapor and temperature is introduced. This system operates in the 720-780-nm region and is configured as an alexandrite ring laser injection seeded by a cw Ti:sapphire ring laser. This combination provides for the necessary narrow-bandwidth, high-frequency stability and excellent spectral purity. A bandwidth of <5.0 x 10(-3) cm(-1), a frequency stability of 2.1 x 10(-3) cm(-1) rms, and a spectral purity of 99.995% at 726 nm have been achieved during extended periods of operation. A comparison of a DIAL water-vapor measurement with a radiosonde in the boundary layer between 500 and 2000 m was performed. The maximum deviation between the humidity profiles is 15%, the standard deviation 1.6%, and the difference between the mean values 1%. PMID:19859281

Wulfmeyer, V; Bösenberg, J; Lehmann, S; Senff, C; Schmitz, S

1995-03-15

330

Future performance of ground-based and airborne water-vapor differential absorption lidar. I. Overview and theory.  

PubMed

The performance of a future advanced water-vapor differential absorption lidar (DIAL) system is discussed. It is shown that the system has to be a direct-detection system operating in the rhovarsigmatau band of water vapor in the 940-nm wavelength region. The most important features of the DIAL technique are introduced: its clear-air measurement capability, its flexibility, and its simultaneous high resolution and accuracy. It is demonstrated that such a DIAL system can contribute to atmospheric sciences over a large range of scales and over a large variety of humidity conditions. An extended error analysis is performed, and errors (e.g., speckle noise) are included that previously were not been discussed in detail and that become important for certain system designs and measurement conditions. The applicability of the derived equation is investigated by comparisons with real data. Excellent agreement is found. PMID:18364811

Wulfmeyer, V; Walther, C

2001-10-20

331

Assessment of water ecological carrying capacity under the two policies in Tieling City on the basis of the integrated system dynamics model.  

PubMed

Considering the limitation of the traditional method to assess the ecological carrying capacity and the complexity of the water ecological system, we used system dynamics, ANN, and CA-Markov to model a water ecological system. The social component was modeled according to Granger causality test by system dynamics. The natural component consists of the water resource and water environmental capacity, which were forecasted through the prediction of precipitation and change in land use cover. The interaction of the social component and the natural component mainly reflected environmental policies, such as the imposition of an environmental fee and environmental tax based on their values. Simulation results showed the different assessments on water ecological carrying capacity under the two policies. The population grew (2.9 million), and less pollution (86,632.37 t COD and 2854.5 t NH4N) was observed with the imposition of environmental tax compared with the imposition of an environmental fee (2.85 million population, 10,8381 t COD and 3543 t NH4N) at the same GDP level of 585 billion CNY in 2030. According to the causality loop, we discussed the different states under the policies and the reasons that caused the differences in water ecological carrying capacity state. According to game theory, we explained the limitation of the environmental fee policy on the basis of marginal benefit and cost. The externality was cleared up by the environmental tax policy. PMID:24361570

Wang, Shuo; Xu, Ling; Yang, Fenglin; Wang, He

2014-02-15

332

Borehole geophysical methods for analyzing specific capacity of multiaquifer wells : ground-water hydraulics  

USGS Publications Warehouse

Conventional well-logging techniques, combined with measurements of flow velocity in the borehole, can provide information on the discharge-drawdown characteriBtic8 of the several aquifers penetrated by a well. The information is most conveniently presented in a graph showing aquifer discharges as functions of the water level in the well at a particular time. To determine the discharge-drawdown characteristics, a well is pumped at a steady rate for a certain length of time. While the well is being pumped, measurements are made of drawdown and of the discharge rates of the individual aquifers within the well. Discharge rates and drawdowns ,are usually recorded as functions of time, and their values for any given time during the test are obtained by interpolation. The procedure is repeated for several different rates of total well discharge. The well may be allowed to recover after each step, or discharge may be changed from one rate to another, and changes in discharge and drawdown may be measured by extrapolation. The flow measurements within the well may be made by use of a subsurface flowmeter or by one of several techniques involving the injection of electrolytic or radioactive tracers. The method was tested on a well in Mercer County, Pa., and provided much useful information on aquifer yields, 'thieving,' and hydrostatic heads of the individual zones.

Bennett, Gordon D.; Patten, Eugene P., Jr.

1960-01-01

333

Efficient tissue ablation using a laser tunable in the water absorption band at 3 microns with little collateral damage  

NASA Astrophysics Data System (ADS)

Lasers can significantly advance medical diagnostics and treatment. At high power, they are typically used as cutting tools during surgery. For lasers that are used as knifes, radiation wavelengths in the far ultraviolet and in the near infrared spectral regions are favored because tissue has high contents of collagen and water. Collagen has an absorption peak around 190 nm, while water is in the near infrared around 3,000 nm. Changing the wavelength across the absorption peak will result in significant differences in laser tissue interactions. Tunable lasers in the infrared that could optimize the laser tissue interaction for ablation and/or coagulation are not available until now besides the Free Electron Laser (FEL). Here we demonstrate efficient tissue ablation using a table-top mid-IR laser tunable between 3,000 to 3,500 nm. A detailed study of the ablation has been conducted in different tissues. Little collateral thermal damage has been found at a distance above 10-20 microns from the ablated surface. Furthermore, little mechanical damage could be seen in conventional histology and by examination of birefringent activity of the samples using a pair of cross polarizing filters.

Nierlich, Alexandra; Chuchumishev, Danail; Nagel, Elizabeth; Marinova, Kristiana; Philipov, Stanislav; Fiebig, Torsten; Buchvarov, Ivan; Richter, Claus-Peter

2014-03-01

334

A Two-Line Absorption Instrument for Scramjet Temperature and Water Vapor Concentration Measurement in HYPULSE  

NASA Technical Reports Server (NTRS)

A three beam water vapor sensor system has been modified to provide for near simultaneous temperature measurement. The system employs a tunable diode laser to scan spectral line of water vapor. The application to measurements in a scramjet combustor environment of a shock tunnel facility is discussed. This report presents and discusses die initial calibration of the measurement system.

Tsai, C. Y.

1998-01-01

335

Wettability, polarity, and water absorption of holm oak leaves: effect of leaf side and age.  

PubMed

Plant trichomes play important protective functions and may have a major influence on leaf surface wettability. With the aim of gaining insight into trichome structure, composition, and function in relation to water-plant surface interactions, we analyzed the adaxial and abaxial leaf surface of holm oak (Quercus ilex) as a model. By measuring the leaf water potential 24 h after the deposition of water drops onto abaxial and adaxial surfaces, evidence for water penetration through the upper leaf side was gained in young and mature leaves. The structure and chemical composition of the abaxial (always present) and adaxial (occurring only in young leaves) trichomes were analyzed by various microscopic and analytical procedures. The adaxial surfaces were wettable and had a high degree of water drop adhesion in contrast to the highly unwettable and water-repellent abaxial holm oak leaf sides. The surface free energy and solubility parameter decreased with leaf age, with higher values determined for the adaxial sides. All holm oak leaf trichomes were covered with a cuticle. The abaxial trichomes were composed of 8% soluble waxes, 49% cutin, and 43% polysaccharides. For the adaxial side, it is concluded that trichomes and the scars after trichome shedding contribute to water uptake, while the abaxial leaf side is highly hydrophobic due to its high degree of pubescence and different trichome structure, composition, and density. Results are interpreted in terms of water-plant surface interactions, plant surface physical chemistry, and plant ecophysiology. PMID:24913938

Fernández, Victoria; Sancho-Knapik, Domingo; Guzmán, Paula; Peguero-Pina, José Javier; Gil, Luis; Karabourniotis, George; Khayet, Mohamed; Fasseas, Costas; Heredia-Guerrero, José Alejandro; Heredia, Antonio; Gil-Pelegrín, Eustaquio

2014-09-01

336

Dry matter yield, nitrogen absorption, and water uptake by sweet corn under salt stress  

Microsoft Academic Search

The response to salinity differs greatly among various plant species. This study was conducted to evaluate the effects of NaCl salinity on growth of corn in terms of dry matter production and nitrogen and water uptake. Dry matter yield and N and water uptake by sweet corn (Zea mays L; cv. “Florida Stay Sweet\\

M. Pessarakli; J. T. Huber; T. C. Tucker

1989-01-01

337

Metal-and hydrogen-bonding competition during water absorption on Pd(111) and Ru(0001)  

SciTech Connect

The initial stages of water adsorption on the Pd(111) and Ru(0001) surfaces have been investigated experimentally by Scanning Tunneling Microscopy in the temperature range between 40 K and 130 K, and theoretically with Density Functional Theory (DFT) total energy calculations and STM image simulations. Below 125 K water dissociation does not occur at any appreciable rate and only molecular films are formed. Film growth starts by the formation of flat hexamer clusters where the molecules bind to the metal substrate through the O-lone pair while making H-bonds with neighboring molecules. As coverage increases, larger networks of linked hexagons are formed with a honeycomb structure, which requires a fraction of the water molecules to have their molecular plane perpendicular to the metal surface with reduced water-metal interaction. Energy minimization favors the growth of networks with limited width. As additional water molecules adsorb on the surface they attach to the periphery of existing islands, where they interact only weakly with the metal substrate. These molecules hop along the periphery of the clusters at intermediate temperatures. At higher temperatures they bind to the metal to continue the honeycomb growth. The water-Ru interaction is significantly stronger than the water-Pd interaction, which is consistent with the greater degree of hydrogen-bonded network formation and reduced water-metal bonding observed on Pd relative to Ru.

Tatarkhanov, Mouslim; Ogletree, D. Frank; Rose, Franck; Mitsui, Toshiyuki; Fomin, Evgeny; Rose, Mark; Cerda, Jorge I.; Salmeron, Miquel

2009-09-03

338

Ratiometric fluorescent nanosensor based on water soluble carbon nanodots with multiple sensing capacities.  

PubMed

A construction strategy for ratiometric fluorescent nanosensors based on water soluble C-dots was developed, which could sense temperature (10-82 °C), pH values (lower than 6.0 or higher than 8.6) and Fe(3+) ions (>0.04 ?M) by monitoring the intensity ratios of dual fluorescence bands (Ib/Ig) under 380 nm excitation. Ib/Ig decreased nearly linearly with increasing temperature from 10 to 82 °C. In the pH range from 8.6 to 6.0, the Ib/Ig was nearly constant at 0.75. Ib/Ig gradually decreased from 0.75 to 0.52 in the pH range from 6.0 to 1.9, and increased nearly linearly from 0.52 to 0.75 in the pH range from 1.9 to 1.0. The dual fluorescence behavior was reversible in the pH range from 1.0 to 8.6. As pH increased from 10.6 to 13.0, the green fluorescence band decreased continuously and blue shifted with a nearly linear increase in Ib/Ig from 0.75 to 2.15, while the green fluorescence band cannot be recovered by decreasing the pH value. Ib/Ig was ultrasensitive and selective in presence of Fe(3+) (>0.04 ?M) in neutral aqueous environments. The two fluorescence bands of the C-dots were attributed to different surface states that may produce different fluorescent signal responses to external physical or chemical stimuli. PMID:23673389

Qu, Songnan; Chen, Hong; Zheng, Xuanming; Cao, Junsheng; Liu, Xingyuan

2013-06-21

339

In situ X-ray absorption study of copper films in ground water solutions  

NASA Astrophysics Data System (ADS)

This study illustrates how the damage from copper corrosion can be reduced by modifying the chemistry of the copper surface environment. The surface modification of oxidized copper films induced by chemical reaction with Cl - and HCO3- in aqueous solutions was monitored by in situ X-ray absorption spectroscopy. The results show that corrosion of copper can be significantly reduced by adding even a small amount of sodium bicarbonate. The studied copper films corroded quickly in chloride solutions, whereas the same solution containing 1.1 mM HCO3- prevented or slowed down the corrosion processes.

Kvashnina, K. O.; Butorin, S. M.; Modin, A.; Soroka, I.; Marcellini, M.; Nordgren, J.; Guo, J.-H.; Werme, L.

2007-10-01

340

Intercomparison of atmospheric water-vapor soundings from the differential absorption lidar (DIAL) and the solar FTIR system on Mt. Zugspitze  

Microsoft Academic Search

Water vapor is a key component for the development of the climate and related atmospheric physics. It is a big challenge to determine how the water-vapor distribution develops, especially in the upper troposphere and lower stratosphere. Therefore, sensitive and accurate measurement techniques with measurement errors smaller than 5% are urgently needed. The differential absorption lidar (DIAL) on Mt. Zugspitze (Schneefernerhaus

Hannes Vogelmann; Ralf Sussmann; Thomas Trickl; Tobias Borsdorff

2010-01-01

341

Watching Hydrogen Bonds Break: A Transient Absorption Study of Water Tobias Steinel, John B. Asbury, Junrong Zheng, and M. D. Fayer*  

E-print Network

Watching Hydrogen Bonds Break: A Transient Absorption Study of Water Tobias Steinel, John B. Asbury of picoseconds, observe hydrogen bond breaking and monitor the equilibration of the hydrogen bond network in water. In addition, the vibrational lifetime, the time constant for hydrogen bond breaking, and the rate

Fayer, Michael D.

342

Metabolic changes associated with active water vapour absorption in the mealworm Tenebrio molitor L. (Coleoptera, Tenebrionidae): a microcalorimetric study.  

PubMed

Water vapour absorption (WVA) is an important mechanism for water gain in several xeric insects. Theoretical calculations indicate that the energetic cost of WVA should be small (5-10% of standard metabolic rate) assuming realistic efficiencies. In this study we explored the relationship between WVA, metabolic heat flux (HFmet.) and CO2 release in larvae of Tenebrio molitor using microcalorimetry. By comparing metabolic heat flux with the catabolic rate estimated from VCO2 , we were able to differentiate anabolic and catabolic rates prior to and during WVA, while simultaneously monitoring water exchange. Three to four hours before the onset of WVA, larvae showed clear increases in HFmet. and catabolic flux, and a simultaneous decrease in anabolic flux. Following the onset of WVA, HFmet. decreased again until indistinguishable from control (non-absorbing) values. Possible factors contributing to the "preparatory phase" are discussed, including mobilization of Malpighian tubule transporters and muscular activity in the rectum. Absorbing larvae reduced the water activity of the calorimetric cell to 0.906, agreeing with gravimetric estimates of the critical equilibrium activity. Periods of movement during WVA coincided with decreased uptake fluxes, consistent with the animal's hydrostatic skeleton and the need to close the anus to generate pressure increases in the haemocoel. PMID:16412458

Hansen, Lars L; Westh, Peter; Wright, Jonathan C; Ramløv, Hans

2006-03-01

343

Design of Advanced Atmospheric Water Vapor Differential Absorption Lidar (DIAL) Detection System  

NASA Technical Reports Server (NTRS)

The measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The lidar atmospheric sensing experiment (LASE) is an instrument designed and operated by the Langley Research Center for high precision water vapor measurements. The design details of a new water vapor lidar detection system that improves the measurement sensitivity of the LASE instrument by a factor of 10 are discussed. The new system consists of an advanced, very low noise, avalanche photodiode (APD) and a state-of-the-art signal processing circuit. The new low-power system is also compact and lightweight so that it would be suitable for space flight and unpiloted atmospheric vehicles (UAV) applications. The whole system is contained on one small printed circuit board (9 x 15 sq cm). The detection system is mounted at the focal plane of a lidar receiver telescope, and the digital output is read by a personal computer with a digital data acquisition card.

Refaat, Tamer F.; Luck, William S., Jr.; DeYoung, Russell J.

1999-01-01

344

Measurement of Water Vapor Concentration using Tunable Diode Laser Absorption Spectroscopy  

E-print Network

4 Effects of pressure broadening on Lorentzian lineshape of water vapor at T = 296K The Beer-Lambert relation, given as I T /I 0 = exp (-k ? P X abs L...), (4) 12 laser I T I 0 cell- T, p, X water pathlength, L Figure 5 Illustration of Beer-Lambert relation can be used to determine the concentration of an individual absorbing species if the pressure, P [atm], path length, L...

Barrett, Alexander B.

2010-07-14

345

Novel fiber optic sensor probe with a pair of highly reflected connectors and a vessel of water absorption material for water leak detection.  

PubMed

The use of a fiber optic quasi-distributed sensing technique for detecting the location and severity of water leakage is suggested. A novel fiber optic sensor probe is devised with a vessel of water absorption material called as water combination soil (WCS) located between two highly reflected connectors: one is a reference connector and the other is a sensing connector. In this study, the sensing output is calculated from the reflected light signals of the two connectors. The first reflected light signal is a reference and the second is a sensing signal which is attenuated by the optical fiber bending loss due to the WCS expansion absorbing water. Also, the bending loss of each sensor probe is determined by referring to the total number of sensor probes and the total power budget of an entire system. We have investigated several probe characteristics to show the design feasibility of the novel fiber sensor probe. The effects of vessel sizes of the probes on the water detection sensitivity are studied. The largest vessel probe provides the highest sensitivity of 0.267 dB/mL, while the smallest shows relatively low sensitivity of 0.067 dB/mL, and unstable response. The sensor probe with a high output value provides a high sensitivity with various detection levels while the number of total installable sensor probes decreases. PMID:23112637

Cho, Tae-Sik; Choi, Ki-Sun; Seo, Dae-Cheol; Kwon, Il-Bum; Lee, Jung-Ryul

2012-01-01

346

Interlayer design for the graphite-like carbon film with high load-bearing capacity under sliding-friction condition in water  

NASA Astrophysics Data System (ADS)

GLC films with single Ti interlayer, single Cr interlayer, thickness gradient Cr/C interlayer and composition gradient Cr/C interlayer were fabricated by magnetron sputtering technique. The microstructures, mechanical properties and tribological performance under sliding friction in distilled water and seawater of the as-deposited GLC films were investigated. Results showed that the adhesion strength and the load-bearing capacity under sliding-friction condition in water of GLC film could be improved effectively by interlayer design. GLC film with composition gradient Cr/C interlayer exhibited highest adhesion strength and load-bearing capacity under sliding-friction conditions in water, which was closely related to nano-interlocked microstructure and hard carbide phase formations inside the interlayer. The adhesion strength in scratch test and the critical bearing load under sliding-friction in water of the GLC film with composition gradient Cr/C interlayer exceeded 50 N and 2.73 GPa, respectively.

Wang, Yongxin; Pu, Jibin; Wang, Jiafan; Li, Jinlong; Chen, Jianmin; Xue, Qunji

2014-08-01

347

High-accuracy measurement of low-water-content in liquid using NIR spectral absorption method  

NASA Astrophysics Data System (ADS)

Water content measurement technologies are very important for quality inspection of food, medicine products, chemical products and many other industry fields. In recent years, requests for accurate low-water-content measurement in liquid are more and more exigent, and great interests have been shown from the research and experimental work. With the development and advancement of modern production and control technologies, more accurate water content technology is needed. In this paper, a novel experimental setup based on near-infrared (NIR) spectral technology and fiber-optic sensor (OFS) is presented. It has a good measurement accuracy about -/+ 0.01%, which is better, to our knowledge, than most other methods published until now. It has a high measurement resolution of 0.001% in the measurement range from zero to 0.05% for water-in-alcohol measurement, and the water-in-oil measurement is carried out as well. In addition, the advantages of this method also include pollution-free to the measured liquid, fast measurement and so on.

Peng, Bao-Jin; Wan, Xu; Jin, Hong-Zhen; Zhao, Yong; Mao, He-Fa

2005-01-01

348

The use of atomic absorption spectroscopy to measure arsenic, selenium, molybdenum, and vanadium in water and soil samples from uranium mill tailings sites  

SciTech Connect

The Technical Measurements Center (TMC) was established to support the environmental measurement needs of the various DOE remedial action programs. A laboratory intercomparison study conducted by the TMC, using soil and water samples from sites contaminated by uranium mill tailings, indicated large discrepancies in analytical results reported by participating laboratories for arsenic, selenium, molybdenum, and vanadium. The present study was undertaken to investigate the most commonly used analytical techniques for measuring these four elements, ascertain routine and reliable quantification, and assess problems and successes of analysts. Based on a survey of the technical literature, the analytical technique of atomic absorption spectroscopy was selected for detailed study. The application of flame atomic absorption, graphite furnace atomic absorption, and hydride generation atomic absorption to the analysis of tailings-contaminated samples is discussed. Additionally, laboratory sample preparation methods for atomic absorption spectroscopy are presented. The conclusion of this report is that atomic absorption can be used effectively for the determination of arsenic, selenium, molybdenum, and vanadium in water and soil samples if the analyst understands the measurement process and is aware of potential problems. The problem of accurate quantification of arsenic, selenium, molybdenum, and vanadium in water and soil contaminated by waste products from uranium milling operations affects all DOE remedial action programs (Surplus Facilities Management Program (SFMP), Formerly Utilized Site Remedial Action Program (FUSRAP), and Uranium Mill Tailings Remedial Action Program (UMTRAP)), since all include sites where uranium was processed. 96 refs., 9 figs.

Hollenbach, M.H.

1988-01-01

349

The impact of regional water resources capacity building: Citations of the published proceedings of the annual WaterNet\\/WARFSA\\/GWP-SA symposia in Southern Africa, 2001–2005  

Microsoft Academic Search

This paper measures the scientific impact of two regional water resources capacity building programmes in Southern Africa: WaterNet and WARFSA. The articles emanating from the annual symposia organised jointly by both programmes during the period 2001–2005 and published in special issues of Physics and Chemistry of the Earth were analysed in terms of numbers and citations. The paper concludes that

Pieter van der Zaag

2007-01-01

350

Water relations and photosynthetic capacity of two species of Calotropis in a tropical semi-arid ecosystem  

PubMed Central

Background and Aims Calotropis procera and Calotropis gigantea, originally from warm parts of Africa and Asia, are now pan-tropical and in ecological terms considered an indicator of overgrazed, disturbed lands; they grow successfully in dry areas. Variations in water relations, morphology and photosynthesis of the two species growing in the same habitat were studied to assess possible mechanisms of tolerance to drought and how these relate to their ecophysiological success. Also the hypothesis that their photosynthetic rate (A) under drought would be affected by stomatal and non-stomatal limitations was tested. Methods Water relations, gas exchange, water use efficiency (WUE), fluorescence parameters, pubescence and specific leaf area (SLA) of Calotropis procera and C. gigantea plants growing in the field were evaluated during the wet (WS) and dry (DS) seasons. Results The xylem water potential (?) was similar in both species during the WS and DS; drought caused a 28 % decrease of ?. In C. procera, A, stomatal conductance (gs) and carboxylation efficiency (CE) were higher in the WS with half the values of those during the DS, this species being more affected by drought than C. gigantea. A high ?13C of C. gigantea (–26·2 ‰) in the WS indicated a higher integrated WUE, in agreement with its lower gs. Leaves of C. gigantea were more pubescent than C. procera. Relative stomatal and non-stomatal limitation of A increased with drought in both species; no changes in maximum quantum yield of photosystem II (PSII; Fv/Fm) were observed. The decrease in the relative quantum yield of PSII (?PSII) and in the photochemical quenching coefficient (qP) was more pronounced in C. procera than in C. gigantea. Conclusions The photosynthetic capacity of C. procera was higher than that of C. gigantea. During the DS, A was regulated by stomatal and non-stomatal factors in a coordinated manner and drought did not cause chronic photoinhibition. A higher density of trichomes and leaf angle in C. gigantea may contribute to the maintenance of A and confer more efficient protection of photochemical activity in the DS. Ecophysiological traits such as high photosynthetic rate throughout the year even during the DS, and high WUE, highly pubescent leaves and low SLA observed in both species contribute to the establishment and growth of Calotropis in dry conditions. PMID:21149276

Tezara, Wilmer; Colombo, Rita; Coronel, Ilsa; Marín, Oranys

2011-01-01

351

Investigation of oil adsorption capacity of granular organoclay media and the kinetics of oil removal from oil-in-water emulsions  

E-print Network

to desalination. Organoclay also pre-polishes the waste water before further treatment. This research studies the efficacy of using organoclay to remove oil by measuring its adsorption capacity to remove the oil from a SAE 30 (Golden West Superior) motor oil...

Islam, Sonia

2007-04-25

352

Micelle mediated extraction of magnesium from water samples with trizma-chloranilate and determination by flame atomic absorption spectrometry.  

PubMed

This article describes an analytical method for the determination of magnesium taking advantage of the cloud point phenomenon employing a suitable chelating agent (chloranilate) for Mg analysis. The method encompasses pre-concentration of the metal chelate followed by flame atomic absorption spectrometry (FAAS) analysis. The chelating agent chosen for this task is a newly synthesised salt of chloranilic acid, trizma-chloranilate, which reacts with Mg but at the same time has a very low affinity for other metallic cations like silicon, aluminium and sodium, which interfere with the determination of Mg in FAAS. The condensed surfactant phase with the metal chelate(s) is introduced into the flame of an atomic absorption spectrometer after its treatment with an acidified methanolic solution. In this way, complex and time-consuming steps for sample treatment are avoided while increased sensitivity is achieved by the presence of both methanol and surfactant in the aspirated sample. The analytical curve was rectilinear in the range of 5-220 mugl(-1) and the limit of detection was as low as 0.75 mugl(-1) with a standard deviation of 5.2%. The method was applied for the determination of Mg in natural and mineral waters with satisfactory results and recoveries in the range of 97-102%. PMID:18968513

Giokas, Dimosthenis L; Paleologos, Evangelos K; Veltsistas, Panayotis G; Karayannis, Miltiades I

2002-03-01

353

Mode of action of beta-cyclodextrin as an absorption enhancer of the water-soluble drug meglumine antimoniate.  

PubMed

It has been previously reported that beta-cyclodextrin (beta-CD) enhances the oral absorption of the pentavalent antimony (Sb) drug, meglumine antimoniate (MA). Contrary to the drugs commonly used in association with beta-CD, MA is highly soluble in water (solubility >300 mg/mL) and, therefore, the mode of action of beta-CD in this system requires clarification. ESI(-)-MS analysis of MA and of the MA/beta-CD composition indicated the formation of a 1:1 association compound between 1:1 Sb-meglumine complex and beta-CD. A stability constant on the order of 100 Lmol(-1) was determined for this association compound. When MA solution was heated for 48 h at 55 degrees C to mimic the conditions used to prepare MA/beta-CD, MA was found to suffer dissociation, from high molecular weight Sb complexes into species of lower molecular weight. Strikingly, heated MA was found to be more extensively absorbed in mice by the oral route than MA freshly prepared at room temperature. In vitro skin permeation experiments using MA and MA/beta-CD indicated a two-fold increase in the Sb flux for MA/beta-CD. These findings support the hypothesis that the improved oral absorption of Sb arises from the increased permeation of MA across lipid bilayers, as a result of the enhanced availability of 1:1 Sb-meglumine complex. PMID:16876345

Martins, Patrícia S; Ochoa, Rosemary; Pimenta, Adriano M C; Ferreira, Lucas A M; Melo, Alan L; da Silva, José B B; Sinisterra, Rubén D; Demicheli, Cynthia; Frézard, Frédéric

2006-11-15

354

Irradiance Inversion Algorithm for Estimating the Absorption and Backscattering Coefficients of Natural Waters: Raman-Scattering Effects  

NASA Astrophysics Data System (ADS)

We modify an algorithm for retrieving the absorption ( a ) and backscattering ( b b ) coefficient profiles in natural waters by inverting profiles of downwelling and upwelling irradiance so as to include the presence of Raman scattering. For a given wavelength of interest, , the light field at the appropriate Raman excitation wavelength e is first inverted to obtain the Raman source function at . Starting from estimates of the inherent optical properties at , the contribution to the irradiances at from Raman scattering is then estimated and subtracted from the total irradiances to obtain the elastically scattered irradiances. We then inverted the elastically scattered irradiances to find new estimates of a and b b using our original method Appl. Opt. 37, 3886 (1998) . The algorithm then operates iteratively: The new estimates are used with the Raman source function to derive a new estimate of the Raman contribution, etc. Sample results are provided that demonstrate the working of the algorithm and show that the absorption and scattering coefficients can be retrieved with accuracies similar to those in the absence of Raman scattering down to depths at which the light field is significantly perturbed by it, e.g., with 90% of the upwelling light field originating from Raman scattering.

Boynton, G. Chris; Gordon, Howard R.

2000-06-01

355

Surfactant/oil/water system for the determination of selenium in eggs by graphite furnace atomic absorption spectrometry  

NASA Astrophysics Data System (ADS)

An oil-in-water formulation has been optimized to determine trace levels of selenium in whole hen eggs by graphite furnace atomic absorption spectrometry. This method is simpler and requires fewer reagents when compared with other sample pre-treatment procedures. Graphite furnace atomic absorption spectrometric (GF AAS) measurement was carried out using standard addition calibration and Pd as a modifier. The precision, expressed as relative standard deviation, was better than 5% and the limit of detection was 1 µg L - 1 . The validation of the method was performed against a standard reference material Whole Egg Powder (RM 8415), and the measured Se corresponded to 95.2% of the certified value. The method was used for the determination of the Se level in eggs from hens treated with Se dietary supplements. Inorganic and organic Se sources were added to hen feed. The Se content of eggs was higher when hens were fed with organic Se compared to the other treatments. The proposed method, including sample emulsification for subsequent Se determination by GF AAS has proved to be sensitive, reproducible, simple and economical.

Ieggli, C. V. S.; Bohrer, D.; Noremberg, S.; do Nascimento, P. C.; de Carvalho, L. M.; Vieira, S. L.; Reis, R. N.

2009-06-01

356

Assessment of the water self-purification capacity on a river affected by organic pollution: application of chemometrics in spatial and temporal variations.  

PubMed

Water pollution caused by organic matter is a major global problem which requires continuous evaluation. Multivariate statistical analysis was applied to assess spatial and temporal changes caused by natural and anthropogenic phenomena along Potrero de los Funes River. Cluster analysis (CA), principal component analysis (PCA) and analysis of variance (ANOVA) were applied to a data set collected throughout a period of 3 years (2010-2012), which monitored 22 physical, chemical and biological parameters. Content of dissolved oxygen in water and biochemical oxygen demand in a watercourse are indicators of pollution caused by organic matter. For this reason, the Streeter-Phelps model was used to evaluate the water self-purification capacity. Hierarchical cluster analysis grouped the sampling sites based on the similarity of water quality characteristics. PCA resulted in two latent factors explaining 75.2 and 17.6 % of the total variance in water quality data sets. Multidimensional ANOVA suggested that organic pollution is mainly due to domestic wastewater run-offs and anthropogenic influence as a consequence of increasing urbanization and tourist influx over the last years. Besides, Streeter-Phelps parameters showed a low reaeration capacity before dam with low concentration of dissolved oxygen. Furthermore, self-purification capacity loss was correlated with the decrease of the Benthic Index. This measurement suggested that biological samplings complement the physical-chemical analysis of water quality. PMID:24888622

González, S Oliva; Almeida, C A; Calderón, M; Mallea, M A; González, P

2014-09-01

357

First-Order Phase Transition in Liquid Water in Terms of the Mode Structure of Absorption Spectrum in the Near-IR Range  

NASA Astrophysics Data System (ADS)

Absorption spectra of liquid water H2O are investigated in the region 4500-5600 cm-1 at temperatures from -53.0 to +20.3°C. The absorption band is decomposed into component modes at (I) 4700, (II) 4890, (III) 5080, and (IV) 5200 cm-1 whose centers are shifted slightly with temperature. Modes (II), (III), and (IV) are present in the spectrum of liquid water, whereas modes (I), (II), and (III) are registered in the spectrum of ice. The appearance of the ordered crystalline lattice is characterized by the occurrence of low-frequency mode (I) and by the disappearance of high-frequency component (IV) of the water absorption band in the region 4500-5600 cm-1. The spectral regions and temperature ranges in which the structure is changed during phase transition are determined.

Sinitsa, L. N.; Lugovskoy, A. A.; Sukhov, A. B.; Poplavskii, Yu. A.

2015-01-01

358

PLASTICIZERS FOR ZEIN: THEIR EFFECT ON TENSILE PROPERTIES AND WATER ABSORPTION OF ZEIN FILMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Zein will gain or lose moisture to reach equilibrium with ambient air. Cast zein films are brittle at room conditions so plasticizers are added to make them more flexible. The amount of water absorbed or lost in these films is known to be affected by relative humidity of the ambient air. However,...

359

Ground-based differential absorption lidar for water-vapor profiling: assessment of accuracy, resolution, and meteorological applications.  

PubMed

The accuracy and the resolution of water-vapor measurements by use of the ground-based differential absorption lidar (DIAL) system of the Max-Planck-Institute (MPI) are determined. A theoretical analysis, intercomparisons with radiosondes, and measurements in high-altitude clouds allow the conclusion that, with the MPI DIAL system, water-vapor measurements with a systematic error of <5% in the whole troposphere can be performed. Special emphasis is laid on the outstanding daytime and nighttime performance of the DIAL system in the lower troposphere. With a time resolution of 1 min the statistical error varies between 0.05 g/m(3) in the near range using 75 m and-depending on the meteorological conditions-approximately 0.25 g/m(3) at 2 km using 150-m vertical resolution. When the eddy correlation method is applied, this accuracy and resolution are sufficient to determine water-vapor flux profiles in the convective boundary layer with a statistical error of <10% in each data point to approximately 1700 m. The results have contributed to the fact that the DIAL method has finally won recognition as an excellent tool for tropospheric research, in particular for boundary layer research and as a calibration standard for radiosondes and satellites. PMID:18273352

Wulfmeyer, V; Bösenberg, J

1998-06-20

360

Flow injection solid phase extraction with Chromosorb 102: determination of lead in soil and waters by flame atomic absorption spectrometry  

NASA Astrophysics Data System (ADS)

A flow-injection, solid-phase extraction, preconcentration method was developed for the determination of lead in soil and water samples by flame atomic absorption spectrometry. Lead, in the form of the diethyldithiocarbamate complex, was retained on a miniature column of Chromosorb 102 from buffered sample solutions. Several parameters governing the efficiency and throughput of the method were evaluated including pH, eluent composition, volume and flow rate. The complex retained from pH 9.0 (ammonium acetate) solutions was eluted with 176 ?l of ethanol, at 4.2 ml min -1 into the nebulizer-burner system of the spectrometer. The detection limit was 2 ?g l -1 for preconcentration at 2.2 ml min -1 for 120 s. The relative standard deviation (R.S.D.) was less than 4% for concentrations down to 400 ?g l -1. The procedure was validated by the analysis of NIST standard reference material 2711 (Montana Soil) which contains lead at a concentration of 1162 ?g g -1. Recoveries of spike additions (100-400 ?g l -1) to artificial sea water and tap water were quantitative.

Elçi, Latif; Arslan, Zikri; Tyson, Julian F.

2000-07-01

361

Determination of aromatic compounds in water by solid phase microextraction and ultraviolet absorption spectroscopy. 2. Application to fuel aromatics  

SciTech Connect

Solid phase microextraction is coupled with ultraviolet absorption spectroscopy to determine fuel aromatic hydrocarbons from unleaded gasoline, jet fuel (JP4), and no. 1 diesel fuel in water. A rectangular `chip` of poly(dimethylsiloxane) (OV-1) was used as the sorbent medium to selectively partition the various fuels from real water matrices without interferences from naturally occurring organics (e.g., humic and fulvic acids). Equilibration times are under 45 min for the majority of aromatic compounds and range from 150 to 300 min for the three fuels. However, it is shown that the fuels can be quantitated at significantly shorter extraction times (45 min), resulting in only a loss of nearly 2x in the detection limits. Detection limits for unleaded gasoline, JP4, and no. 1 diesel fuel (obtained at their 100% equilibration times) are 4.9, 17, and 9.0 ppb, respectively. In addition, recovery data for the aromatic components from unleaded gasoline, JP4, and no. 1 diesel fuel from two real water matrices are in the range of 87-106%, with RSDs in the range of 5.0-10%. 4 refs., 2 figs., 6 tabs.

Wittkamp, B.L.; Tilotta, D.C.; Hawthorne, S.B. [Univ. of North Dakota, Grand Forks, ND (United States)] [Univ. of North Dakota, Grand Forks, ND (United States)

1997-03-15

362

Compressive Strength and Water Absorption of Pervious Concrete that Using the Fragments of Ceramics and Roof Tiles  

NASA Astrophysics Data System (ADS)

Pervious concrete was introduced in America in 2003, popularized by Dan Brown and used as a rigid pavement in the open parking lot. Rigid pavement using pervious concrete can absorb water in the surface to go straight through the concrete to the ground below.This water flow is one of the benefit of using the pervious concrete. Using of wastes such as broken roof and ceramics tiles are not commonly used in Indonesia. Utilization these kind of wastes is predicted lower the compressive strength of pervious concrete as they are used as a substitute for coarse aggregate.In this research, pervious concrete is made using a mixture of the fragment of ceramics and roof tiles.This research using broken ceramics and roof tiles with a grain size that loose from 38 mm sieve, retained on 19 mm sieve and the coarse aggregate from crushed stone that loose 12.5 mm sieve, retained on 9.5 mm sieve. The water cement ratio is 0.3 and to assist the mixing process, the addition of addictive in pervious concrete is used.The size of coarse aggregate used in the mixture affects the strength of pervious concrete. The larger the size of aggregate, the obtained compressive strength becomes smaller. It also affects the density of pervious concrete. The using of mixture of ceramics and roof tiles only reduce 2 MPa of pervious concrete compressive strength so this mixture can be used as a substitute for coarse aggregate with a maximum portion of 30 %. The high porosity of the specimens causes the reduction of pervious concrete density that affect the compressive strength. This high level of porosity can be seen from the high level of water absorption that exceed the required limit of water infiltration.

Prahara, E.; Meilani

2014-03-01

363

Emission from Water Vapor and Absorption from Other Gases at 5-7.5 ?m in Spitzer-IRS Spectra of Protoplanetary Disks  

NASA Astrophysics Data System (ADS)

We present spectra of 13 T Tauri stars in the Taurus-Auriga star-forming region showing emission in Spitzer Space Telescope Infrared Spectrograph 5-7.5 ?m spectra from water vapor and absorption from other gases in these stars' protoplanetary disks. Seven stars' spectra show an emission feature at 6.6 ?m due to the ?2 = 1-0 bending mode of water vapor, with the shape of the spectrum suggesting water vapor temperatures >500 K, though some of these spectra also show indications of an absorption band, likely from another molecule. This water vapor emission contrasts with the absorption from warm water vapor seen in the spectrum of the FU Orionis star V1057 Cyg. The other 6 of the 13 stars have spectra showing a strong absorption band, peaking in strength at 5.6-5.7 ?m, which for some is consistent with gaseous formaldehyde (H2CO) and for others is consistent with gaseous formic acid (HCOOH). There are indications that some of these six stars may also have weak water vapor emission. Modeling of these stars' spectra suggests these gases are present in the inner few AU of their host disks, consistent with recent studies of infrared spectra showing gas in protoplanetary disks.

Sargent, B. A.; Forrest, W.; Watson, Dan M.; D'Alessio, P.; Calvet, N.; Furlan, E.; Kim, K. H.; Green, J.; Pontoppidan, K.; Richter, I.; Tayrien, C.

2014-09-01

364

[Determination of trace lead in water and milk tea powder samples with organic coprecipitation-flame atomic absorption spectrometric].  

PubMed

A method was proposed for the determination of trace lead with flame atomic absorption spectrometry after preconcentration of lead by rapid coprecipitation technique with PAR-Fe (III) at pH 6.0. The analytical parameters including pH, amount of iron (III), amount of reagent, the standing time of the precipitate, etc., were examined. The detection limits (DL) were found to be 18.7 microg x L(-1) for Pb (II). In analysis of lake water and the milk tea powder samples, RSD's and the standard addition recovery of this method were in the ranges of 1.03%-2.24% and 94.2%-98.3% respectively. The effect of matrix can be overcome by the method and the results are satisfyiog. The method shows good application prospect in the determination of trace lead owing to its rapidness and reproducibility. PMID:23905351

Lin, Jian-Mei; Yao, Jun-Xue; Zhao, Wen-Yan

2013-05-01

365

Impact of the analytical blank in the uncertainty evaluation of the copper content in waters by flame atomic absorption spectrometry.  

PubMed

Chemical analysts use analytical blanks in their analyses, but seldom is this source of uncertainty evaluated. Generally, there is great confusion. Although the numerical value of the blank, in some situations, can be negligible, its source of uncertainty cannot be. This article discusses the uncertainty contribution of the analytical blank using a numerical example of the copper content in waters by flame atomic absorption spectrometry. The results indicate that the uncertainties of the analytical blank can contribute up to 50% when the blank sample is considered in this analysis, confirming its high impact. This effect can be primarily observed where the analyte concentration approaches the lower range of the analytical curve. Even so, the blank is not always computed. Therefore, the relevance of the analytical blank can be confirmed by uncertainty evaluation. PMID:22649945

de Oliveira, Elcio Cruz; Monteiro, Maria Inês Couto; Pontes, Fernanda Veronesi Marinho; de Almeida, Marcelo Dominguez; Carneiro, Manuel Castro; da Silva, Lílian Irene Dias; Alcover Neto, Arnaldo

2012-01-01

366

A comparison of simultaneous plasma, atomic absorption, and iron colorimetric determinations of major and trace constituents in acid mine waters  

USGS Publications Warehouse

Sixty-three water samples collected during June to October 1982 from the Leviathan/Bryant Creek drainage basin were originally analyzed by simultaneous multielement direct-current plasma (DCP) atomic-emission spectrometry, flame atomic-absorption spectrometry, graphite-furnace atomic-absorption spectrometry (GFAAS) (thallium only), ultraviolet-visible spectrometry, and hydride-generation atomic-absorption spectrometry.Determinations were made for the following metallic and semi-metallic constituents: AI, As, B, Ba, Be, Bi, Cd, Ca, Cr, Co, Cu, Fe(11), Fe(total), Li, Pb, Mg, Mn, Mo, Ni, K, Sb, Se, Si, Na, Sr, TI, V, and Zn. These samples were re-analyzed later by simultaneous multielement inductively coupled plasma (ICP) atomic-emission spectrometry and Zeeman-corrected GFAAS to determine the concentrations of many of the same constituents with improved accuracy, precision, and sensitivity. The result of this analysis has been the generation of comparative concentration values for a significant subset of the solute constituents. Many of the more recently determined values replace less-than-detection values for the trace metals; others constitute duplicate analyses for the major constituents. The multiple determinations have yielded a more complete, accurate, and precise set of analytical data. They also have resulted in an opportunity to compare the performance of the plasma-emission instruments operated in their respective simultaneous multielement modes. Flame atomic-absorption spectrometry was judged best for Na and K and hydride-generation atomic-absorption spectrometry was judged best for As because of their lower detection limit and relative freedom from interelement spectral effects. Colorimetric determination using ferrozine as the color agent was judged most accurate, precise, and sensitive for Fe. Cadmium, lead, and vanadium concentrations were too low in this set of samples to enable a determination of whether ICP or DCP is a more suitable technique. Of the remaining elements, Ba, Be, Ca, Cr, Mg, Mn, Sr, and Zn have roughly equivalent accuracy, precision, and detection limit by ICP and DCP. Cobalt and Ni were determined to be better analyzed by ICP, because of lower detection limits; B, Cu, Mo, and Si were determined to be better analyzed by DCP, because of relative freedom from interferences. The determination oral by DCP was far more sensitive, owing to the use of a more sensitive wavelength, compared with the ICP. However, there is a very serious potential interference from a strong Ca emission line near the 396.15 nanometer DCP wavelength. Thus, there is no clear choice between the plasma techniques tested, for the determination oral. The ICP and DCP detection limits are typically between 0.001 and 0.5 milligrams per liter in acid mine waters. For those metals best analyzed by ICP and/or DCP, but below these limits, GFAAS is the method of choice because of its relatively greater sensitivity and specificity. Six of the elements were not determined by DCP, ICP or Zeeman-corrected GFAAS, and are not discussed in this report. These elements are: Bi, Fe(11), Li, Sb, Se, and TI.

Ball, J.W.; Nordstrom, D.K.

1994-01-01

367

Effect of water-films on the absorption of membrane absorbers  

Microsoft Academic Search

The membrane absorber is a fibre-free absorber which consists of vibrating metal membranes on a lightweight metal honeycomb structure. An advantage of this absorber is that the smooth cover-membrane seals the component against humidity and solid particles. In some cases the cover-membrane still needs to be frequently cleaned, and a flowing water-film can be used for this purpose. In this

J. Kang; H. V. Fuchs

1999-01-01

368

Water vapor absorption line intensities in the 1900–6600 cm ?1 region  

Microsoft Academic Search

Water vapor infrared spectra have been measured using the Bruker IFS 120 HR Fourier transform spectrometer at the Physikalisch-Chemisches Institut of the Justus-Liebig-Universität Giessen. Spectra were recorded at pressure-broadening-limited resolution and at room temperature in the range of 1900–6600cm?1. The use of fully evacuated transfer optics and a White-type multireflection cell made it possible to obtain pressure×pathlength products up to

S. N. Mikhailenko; K. A. Keppler Albert; G. Mellau; S. Klee; B. P. Winnewisser; M. Winnewisser; Vl. G. Tyuterev

2008-01-01

369

Multilayer Cloud Detection with the MODIS Near-Infrared Water Vapor Absorption Band  

NASA Technical Reports Server (NTRS)

Data Collection 5 processing for the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the NASA Earth Observing System EOS Terra and Aqua spacecraft includes an algorithm for detecting multilayered clouds in daytime. The main objective of this algorithm is to detect multilayered cloud scenes, specifically optically thin ice cloud overlying a lower-level water cloud, that presents difficulties for retrieving cloud effective radius using single layer plane-parallel cloud models. The algorithm uses the MODIS 0.94 micron water vapor band along with CO2 bands to obtain two above-cloud precipitable water retrievals, the difference of which, in conjunction with additional tests, provides a map of where multilayered clouds might potentially exist. The presence of a multilayered cloud results in a large difference in retrievals of above-cloud properties between the CO2 and the 0.94 micron methods. In this paper the MODIS multilayered cloud algorithm is described, results of using the algorithm over example scenes are shown, and global statistics for multilayered clouds as observed by MODIS are discussed. A theoretical study of the algorithm behavior for simulated multilayered clouds is also given. Results are compared to two other comparable passive imager methods. A set of standard cloudy atmospheric profiles developed during the course of this investigation is also presented. The results lead to the conclusion that the MODIS multilayer cloud detection algorithm has some skill in identifying multilayered clouds with different thermodynamic phases

Wind, Galina; Platnick, Steven; King, Michael D.; Hubanks, Paul A,; Pavolonis, Michael J.; Heidinger, Andrew K.; Yang, Ping; Baum, Bryan A.

2009-01-01

370

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of chromium in water by graphite furnace atomic absorption spectrophotometry  

USGS Publications Warehouse

Graphite furnace atomic absorption spectrophotometry is a sensitive, precise, and accurate method for the determination of chromium in natural water samples. The detection limit for this analytical method is 0.4 microg/L with a working linear limit of 25.0 microg/L. The precision at the detection limit ranges from 20 to 57 percent relative standard deviation (RSD) with an improvement to 4.6 percent RSD for concentrations more than 3 microg/L. Accuracy of this method was determined for a variety of reference standards that was representative of the analytical range. The results were within the established standard deviations. Samples were spiked with known concentrations of chromium with recoveries ranging from 84 to 122 percent. In addition, a comparison of data between graphite furnace atomic absorption spectrophotometry and direct-current plasma atomic emission spectrometry resulted in suitable agreement between the two methods, with an average deviation of +/- 2.0 microg/L throughout the analytical range.

McLain, B.J.

1993-01-01

371

Characterization of Ligand Effects on Water Activation in Triarylphosphoine-Stabilized Pt Nanoparticle Catalysts by X-ray Absorption Spectroscopy  

SciTech Connect

The synthesis, preparation, and electrochemical characterization of triphenylphosphine triphosphonate (TPPTP) stabilized Pt particles have been reported previously with the observation that the TPPTP ligands increase the specific activity of Pt for the oxygen reduction reaction (ORR). In this work the ORR activity of the Pt/TPPTP electrocatalyst is probed by analyzing water activation with Pt L3-edge X-ray absorption spectroscopy and the EXAFS and Delta XANES analysis techniques. The results are compared with that for similarly prepared Pt/C and Pt stabilized by an oxidized TPPTP ligand (Pt/ox-TPPTP). The Pt particles in the Pt/TPPTP catalyst at 0.54 V (RHE) are complexed via the P (i.e., Pt-Pwater activation and the ORR. The relative importance of site blocking, hydrophobic effects, and electronic effects are discussed with hydrophobic effects believed to dominate in the Pt/TPPTP catalyst and site blocking in the Pt/ox-TPPTP catalyst.

Gatewood,D.; Schull, T.; Baturina, O.; Pietron, J.; Garsany, Y.; Swider-Lyons, K.; Ramaker, D.

2008-01-01

372

Role of iron and organic carbon in mass-specific light absorption by particulate matter from Louisiana coastal waters  

E-print Network

Role of iron and organic carbon in mass-specific light absorption by particulate matter from iron, and dithionite-extractable iron contents. Compositions and absorption properties were comparable to published values for similar particles. Dithionite-extractable iron was strongly correlated with absorption

Boss, Emmanuel S.

373

Flow Injection Hydride Generation Atomic Absorption Spectrometry for Determination of Arsenic in Water and Biological Samples from Arsenic-Affected Districts of West Bengal, India, and Bangladesh  

Microsoft Academic Search

The increasing concern over human exposure to arsenic in West Bengal and Bangladesh has necessitated the development of a rapid method for determination of trace levels of arsenic in water and biological samples. We have developed a simple indigenous flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) system for the determination of arsenic in parts-per-billion levels in water and biological

Gautam Samanta; Tarit Roy Chowdhury; Badal K. Mandal; Bhajan K. Biswas; Uttam K. Chowdhury; Gautam K. Basu; Chitta R. Chanda; Dilip Lodh; Dipankar Chakraborti

1999-01-01

374

Sorption and desorption of pesticide in the octadecylsilyl-silica gel\\/water system by single microparticle injection and absorption microspectroscopy  

Microsoft Academic Search

The sorption and desorption processes of a pesticide between a single octadecylsilyl (ODS)-silica gel microparticle and the surrounding water phase were kinetically analyzed by absorption microspectroscopy combined with a single microparticle injection method. 2-Amino-3-chloro-1,4-naphthoquinone (quinoclamine) sorbed into the microparticle was completely desorbed into the water phase, and both the sorption and desorption processes could be analyzed by the intraparticle diffusion

Katsumi Chikama; Hiroshi Kakizaki; Kiyoharu Nakatani

2008-01-01

375

Direct calculations of vibrational absorption and circular dichroism spectra of alanine dipeptide analog in water: Quantum mechanical\\/molecular mechanical molecular dynamics simulations  

Microsoft Academic Search

The vibrational absorption (IR) and vibrational circular dichroism (VCD) spectra of alanine dipeptide analog in water are directly calculated by Fourier transforming the time correlation functions of the electric and magnetic dipole moments, which are calculated using the dynamic partial charges and trajectory of the peptide generated from the quantum mechanical\\/molecular mechanical molecular dynamics simulations. The alanine dipeptide analog is

Seongeun Yang; Minhaeng Cho

2009-01-01

376

Mineral Specific IR Molar Absorption Coefficients for Routine Water Determination in Olivine, SiO2 polymorphs and Garnet  

NASA Astrophysics Data System (ADS)

Conventionally applied Infrared (IR) calibrations [1, 2] for quantitative water analyses in solids are established on hydrous minerals and glasses with several wt% water. These calibrations are based on a negative correlation between the IR molar absorption coefficient (?) for water and the mean wavenumber of the corresponding OH pattern. The correlation reflects the dependence of the OH band position on the appropriate O- H...O distances and thereby the magnitude of the dipole momentum which is proportional to the band intensity. However, it has been observed that these calibrations can not be adopted to nominally anhydrous minerals (NAMs) [3].To study the potential dependence of ? on structure and chemistry in NAMs we synthesized olivine and SiO2 polymorphs with specific isolated hydroxyl point defects, e.g. quartz, coesite and stishovite with B3++H+=Si4+ and/or Al3++H+=Si4+ substitutions. Experiments were performed with water in excess in piston cylinder and multi-anvil presses. Single crystal IR spectra demonstrate that we successfully managed to seperate generally complex OH patterns as e.g. observed in natural quartz and synthetic coesite. We quantified sample water contents of both natural samples and our run products by applying proton-proton-scattering [4], confocal microRaman spectroscopy [5] and Secondary Ion mass spectrometry. Resulting water concentrations were used to calculate new mineral specific ?s. For olivine with the mean wavenumber of 3517 cm-1 we determined an ? value of 41,000±5,000 lmol-1H2Ocm-2. Quantification of olivine with the mean wavenumber of 3550 cm-1 in contrast resulted in an ? value of 47,000±1,000 lmol-1H2Ocm-2. Taking into account previous studies [6, 7] there is evidence to suggest a linear wavenumber dependent correlation for olivine, where ? increases with decreasing wavenumber. In case of the SiO2 system it turns out that the magnitude of ? within one structure type is independent of the liable OH point defect and therewith the wavenumber of the observed band position. Consequently, one single mean ? of 68,000±5,000 lmol-1H2Ocm-2 could be determined for a suite of quartz samples with varying OH point defects. In contrast, ? varies with the structure itself. For polymorphic coesite we calculated a different ? of 214,000±8,000 lmol-1H2O}cm-2, that is in good agreement with earlier established data [8]. Quantification data of stishovite resulted in an even higher value of ?=867,000±29,000 lmol-1H2Ocm-2, similar to that determined by [9]. First data on natural garnet give an ? value of 40,000±2,000 lmol-1H2Ocm-2, that confirms prior suggested values [10]. Our results demonstrate that not using mineral specific calibrations for quantitative water analyses in NAMs leads to overestimation of sample water concentrations, that are required for modelling the earth's deep water cycle. [1]Paterson, M. S. (1982), Bull. Min., 105, 20-29. [2]Libowitzky, E., Rossman, G. R. (1997), Am. Min., 82, 1111- 1115. [3]Rossman, G. R. (2006), Rev. Mineral., 62, 1-28. [4]Reichart et al. (2004), Science, 306, 1537-1540. [5]Thomas et al. (2006), Am. Min., 91, 467-470. [6]Bell et al. (2003), JGR, 108, (B2), 2105-2113. [7]Koch-Mueller et al. (2006), PCM, 33, 276-287. [8]Koch-Mueller et al. (2001), PCM, 28, 693-705. [9]Pawley et al. (1993), Science, 261, 1024-1026. [10]Maldener et al. (2003), PCM, 30, 337-344.

Thomas, S.; Koch-Mueller, M.; Reichart, P.; Rhede, D.; Thomas, R.

2007-12-01

377

Measurement and Model Correlation of Specific Heat Capacity of Water-Based Nanofluids With Silica, Alumina and Copper Oxide Nanoparticles  

E-print Network

Nanofluids are being considered for heat transfer applications. However, their thermo-physical properties are poorly known. Here we focus on nanofluid specific heat capacity. Currently, there exist two models to predict a ...

O’Hanley, Harry

378

Osmoregulative capacity in birdseed millet under conditions of water stress. I. Variation in Setaria italica and Panicum miliaceum  

Microsoft Academic Search

Experiments involving 14 accessions of Panicum miliaceum L. (Proso millet) and 11 accessions of Setaria italicaL. (Foxtail millet) have demonstrated variability in the degree of osmoregulative capacity among these accessions. Birdseed\\u000a millet is generally claimed to be sensitive to drought stress, apparently because of a shallow root system. Accessions with\\u000a high osmoregulative capacity demonstrate at least some drought tolerance. Osmoregulative

Karyudi; R. J. Fletcher

2002-01-01

379

Systematic trend of water vapour absorption in red giant atmospheres revealed by high resolution TEXES 12 ?m spectra  

NASA Astrophysics Data System (ADS)

Context. The structures of the outer atmospheres of red giants are very complex. Recent interpretations of a range of different observations have led to contradictory views of these regions. It is clear, however, that classical model photospheres are inadequate to describe the nature of the outer atmospheres. The notion of large optically thick molecular spheres around the stars (MOLspheres) has been invoked in order to explain spectro-interferometric observations and low- and high-resolution spectra. On the other hand high-resolution spectra in the mid-IR do not easily fit into this picture because they rule out any large sphere of water vapour in LTE surrounding red giants. Aims: In order to approach a unified scenario for these outer regions of red giants, more empirical evidence from different diagnostics are needed. Our aim here is to investigate high-resolution, mid-IR spectra for a range of red giants, spanning spectral types from early K to mid M. We want to study how the pure rotational lines of water vapour change with effective temperature, and whether we can find common properties that can put new constraints on the modelling of these regions, so that we can gain new insights. Methods: We have recorded mid-IR spectra at 12.2 - 12.4 ?m at high spectral resolution of ten well-studied bright red giants, with TEXES mounted on the IRTF on Mauna Kea. These stars span effective temperatures from 3450 K to 4850 K. Results: We find that all red giants in our study cooler than 4300 K, spanning a wide range of effective temperatures (down to 3450 K), show water absorption lines stronger than expected and none are detected in emission, in line with what has been previously observed for a few stars. The strengths of the lines vary smoothly with spectral type. We identify several spectral features in the wavelength region that are undoubtedly formed in the photosphere. From a study of water-line ratios of the stars, we find that the excitation temperatures, in the line-forming regions, are several hundred Kelvin lower than expected from a classical photospheric model. Conclusions: All stars in our sample show several photospheric features in their 12 ?m spectra, which can be modelled with a classical model photosphere. However, in all stars showing water-vapour lines (stars cooler than ~4300 K), the water lines are found to be much deeper than expected. The line ratios of these pure-rotational lines reveal low excitation temperatures. This could either be due to lower temperatures than expected in the outer regions of the photospheres caused by for example extra cooling, or due to non-LTE level populations, affecting the source function and line opacities, but this needs further investigation. We have demonstrated that these diagnostically interesting water lines are a general feature of red giants across spectral types, and we argue for a general explanation of their formation rather than explanations requiring specific properties, such as dust. Since the water lines are neither weak (filled in by emission) nor do they appear in emission, as predicted by LTE MOLsphere models in their simplest forms, the evidence of the existence of such large optically-thick, molecular spheres enshrouding the stars is weakened. It is still a challenge to find a unifying picture of the outer regions of the atmospheres of red giants, but we have presented new empirical evidence that needs to be taken into account and explained in any model of these regions. Table 4 is available in electronic form at http://www.aanda.org

Ryde, N.; Lambert, J.; Farzone, M.; Richter, M. J.; Josselin, E.; Harper, G. M.; Eriksson, K.; Greathouse, T. K.

2015-01-01

380

Kinetic Study of the Scavenging Reaction of the Aroxyl Radical by Seven Kinds of Rice Bran Extracts in Ethanol Solution. Development of an Aroxyl Radical Absorption Capacity (ARAC) Assay Method.  

PubMed

Recently, a new assay method that can quantify the aroxyl radical (ArO•) absorption capacity (ARAC) of antioxidants (AOHs) was proposed. In the present work, the second-order rate constants (ks(Extract)) and ARAC values for the reaction of ArO• with seven kinds of rice bran extracts 1-7, which contain different concentrations of ?-, ?-, ?-, and ?-tocopherols and -tocotrienols (?-, ?-, ?-, and ?-Tocs and -Toc-3s) and ?-oryzanol, were measured in ethanol at 25 °C using stopped-flow spectrophotometry. The ks(Extract) value (1.26 × 10(-2) M(-1) s(-1)) of Nipponbare (extract 1) with the highest activity was 1.5 times larger than that (8.29 × 10(-3)) of Milyang-23 (extract 7) with the lowest activity. The concentrations (in mg/100 g) of ?-, ?-, ?-, and ?-Tocs and -Toc-3s and ?-oryzanol found in the seven extracts 1-7 were determined using HPLC-MS/MS and UV-vis absorption spectroscopy, respectively. From the results, it has been clarified that the ArO•-scavenging rates (ks(Extract)) (that is, the relative ARAC value) obtained for the seven extracts 1-7 may be approximately explained as the sum of the product {? ks(AOH-i) [AOH-i]/10(5)} of the rate constant (ks(AOH-i)) and the concentration ([AOH-i]/10(5)) of AOH-i (Tocs, Toc-3s, and ?-oryzanol) included in rice bran extracts. The contribution of ?-oryzanol to the ks(Extract) value was estimated to be between 3.0-4.7% for each extract. Taken together, these results suggest that the ARAC assay method is applicable to general food extracts. PMID:25393029

Mukai, Kazuo; Ouchi, Aya; Abe, Takumi; Murata, Kazumasa; Nakagawa, Kiyotaka; Miyazawa, Teruo

2014-12-10

381

Characterization of Ligand Effects on Water Activation in Triaryl Phospine Stabilized Pt Nanoparticle Catalysts by X-ray Absorption Spectroscopy  

SciTech Connect

The synthesis, preparation, and electrochemical characterization of triphenylphosphine triphosphonate (TPPTP) stabilized Pt particles have been reported previously with the observation that the TPPTP ligands increase the specific activity of Pt for the oxygen reduction reaction (ORR). In this work the ORR activity of the Pt/TPPTP electrocatalyst is probed by analyzing water activation with Pt L{sub 3}-edge X-ray absorption spectroscopy and the EXAFS and Delta XANES analysis techniques. The results are compared with that for similarly prepared Pt/C and Pt stabilized by an oxidized TPPTP ligand (Pt/ox-TPPTP). The Pt particles in the Pt/TPPTP catalyst at 0.54 V (RHE) are complexed via the P (i.e., Pt-Pwater activation and the ORR. The relative importance of site blocking, hydrophobic effects, and electronic effects are discussed with hydrophobic effects believed to dominate in the Pt/TPPTP catalyst and site blocking in the Pt/ox-TPPTP catalyst.

Gatewood, D.; Schull, T; Baturina, O; Pietron, J; Garsany, Y; Swider-Lyons, K; Ramaker, D

2008-01-01

382

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of antimony by automated-hydride atomic absorption spectrophotometry  

USGS Publications Warehouse

The analysis of natural-water samples for antimony by automated-hydride atomic absorption spectrophotometry is described. Samples are prepared for analysis by addition of potassium and hydrochloric acid followed by an autoclave digestion. After the digestion, potassium iodide and sodium borohydride are added automatically. Antimony hydride (stibine) gas is generated, then swept into a heated quartz cell for determination of antimony by atomic absorption spectrophotometry. Precision and accuracy data are presented. Results obtained on standard reference water samples agree with means established by interlaboratory studies. Spike recoveries for actual samples range from 90 to 114 percent. Replicate analyses of water samples of varying matrices give relative standard deviations from 3 to 10 percent.

Brown, G.E.; McLain, B.J.

1994-01-01

383

Cloud point extraction-flame atomic absorption spectrometry method for preconcentration and determination of trace cadmium in water samples.  

PubMed

A method based on cloud point extraction (CPE) separation/preconcentration of trace cadmium (Cd) as a prior step to its determination by flame atomic absorption spectrometry has been developed. Cadmium reacted with 8-hydroxyquinoline to form hydrophobic chelates, which were extracted into the micelles of nonionic surfactant oligoethylene glycol monoalkyl ether (Genapol X-080) in an alkaline medium. Octanol was used to depress the cloud point of Genapol X-080 in the extraction process. The chemical variables that affect the CPE, such as pH of complexation reaction, amount of chelating agent, Genapol X-080 and octanol were evaluated and optimized. Under optimized conditions, linearity was obeyed in the range of 10-500 ?g/L, with the correlation coefficient of 0.9993. For 5 mL of sample solution, the enhancement factor was about 20. The limit of detection and limit of quantification of the method were 0.21 and 0.63 ?g/L, respectively. The relative standard deviations (n = 6) was 3.2% for a solution containing 100 ?g/L of Cd. The accuracy of the preconcentration system was evaluated by recovery measurements on spiked water samples. Recoveries of spiked samples varied in the range of 94.1-103.8%. PMID:25116488

Ning, Jinyan; Jiao, Yang; Zhao, Jiao; Meng, Lifen; Yang, Yaling

2014-01-01

384

Speciation of selenium in plant water extracts by ion exchange chromatography-hydride generation atomic absorption spectrometry.  

PubMed

Determination of selenium (Se) speciation in plants is important in studying the bioavailability and toxicity of Se in Se-contaminated soil/sediment. In this study, we used an anion exchange resin (Dowex 1-10X) to separate Se into non-amino acid organic Se, Se-amino acids, selenite (Se [IV]) and selenate (Se [VI]) in a plant (Stanleya pinnata) extract. The hydride generation atomic absorption spectrometry (HGAAS) was used to determine concentrations of these Se compounds in plant extracts. Results showed that Se compounds can be quantitatively separated by the resin column. Recovery of five spiked standard Se compounds (trimethylselenonium ion (TMSe+), dimethylselenoxide (DMSeO), selenomethionine (Semet), Se [IV] and Se [VII]) in the plant extract ranged from 92.9 to 103%. Water extractable Se accounted for 60.4-72.6% of the total Se in the plant. Among the soluble Se compounds in the plant extract, Se-amino acids were 73-85.5%, Se [VI] ranged from 7.5 to 19.5% and non-amino acid organic Se was less than 7%. Se [IV] in most samples was below the detection limit (1 microg/g). This study showed that considerable amounts of the accumulated Se [VI] in the plant was metabolized to Se-amino acids during growth of the plant. PMID:11305342

Zhang, Y; Frankenberger, W T

2001-03-26

385

Particle emission from polymer-doped water ice matrices induced by non-linear absorption of laser light at 1064 nm  

NASA Astrophysics Data System (ADS)

Emission of PEG (polyethylene glycol) molecules and ions from an ice target induced by laser irradiation in the infrared (IR) regime at 1064 nm was studied. Matrices of 1% weight PEG flash-frozen solutions were used for polymer deposition with MAPLE (matrix-assisted pulsed laser evaporation). Even though linear absorption in defect-free water ice is two orders of magnitude larger at 1064 nm than 355 nm, the deposition rate and ion current density are much smaller for IR than for ultraviolet laser light. The similarity of results for both wavelengths indicates that non-linear absorption by electrons via optical breakdown is dominant.

Purice, Andreea; Schou, Jørgen; Dinescu, Maria

2006-08-01

386

On the influence of water on the electronic structure of firefly oxyluciferin anions from absorption spectroscopy of bare and monohydrated ions in vacuo.  

PubMed

A complete understanding of the physics underlying the varied colors of firefly bioluminescence remains elusive because it is difficult to disentangle different enzyme-lumophore interactions. Experiments on isolated ions are useful to establish a proper reference when there are no microenvironmental perturbations. Here, we use action spectroscopy to compare the absorption by the firefly oxyluciferin lumophore isolated in vacuo and complexed with a single water molecule. While the process relevant to bioluminescence within the luciferase cavity is light emission, the absorption data presented here provide a unique insight into how the electronic states of oxyluciferin are altered by microenvironmental perturbations. For the bare ion we observe broad absorption with a maximum at 548 ± 10 nm, and addition of a water molecule is found to blue-shift the absorption by approximately 50 nm (0.23 eV). Test calculations at various levels of theory uniformly predict a blue-shift in absorption caused by a single water molecule, but are only qualitatively in agreement with experiment highlighting limitations in what can be expected from methods commonly used in studies on oxyluciferin. Combined molecular dynamics simulations and time-dependent density functional theory calculations closely reproduce the broad experimental peaks and also indicate that the preferred binding site for the water molecule is the phenolate oxygen of the anion. Predicting the effects of microenvironmental interactions on the electronic structure of the oxyluciferin anion with high accuracy is a nontrivial task for theory, and our experimental results therefore serve as important benchmarks for future calculations. PMID:23557511

Støchkel, Kristian; Hansen, Christian Nygaard; Houmøller, Jørgen; Nielsen, Lisbeth Munksgaard; Anggara, Kelvin; Linares, Mathieu; Norman, Patrick; Nogueira, Fernando; Maltsev, Oleg V; Hintermann, Lukas; Brøndsted Nielsen, Steen; Naumov, Pan?e; Milne, Bruce F

2013-05-01

387

Carrying Capacity  

NSDL National Science Digital Library

This one-day activity challenges students to understand the ecological concept of carrying capacity through the physically-active process of role playing. Upon completion, students will be able to formulate and test hypotheses related to ecosystems and carrying capacity as well as describe the significance of carrying capacity.

2012-06-25

388

Heat Capacity Analysis Report  

SciTech Connect

The purpose of this report is to provide heat capacity values for the host and surrounding rock layers for the waste repository at Yucca Mountain. The heat capacity representations provided by this analysis are used in unsaturated zone (UZ) flow, transport, and coupled processes numerical modeling activities, and in thermal analyses as part of the design of the repository to support the license application. Among the reports that use the heat capacity values estimated in this report are the ''Multiscale Thermohydrologic Model'' report, the ''Drift Degradation Analysis'' report, the ''Ventilation Model and Analysis Report, the Igneous Intrusion Impacts on Waste Packages and Waste Forms'' report, the ''Dike/Drift Interactions report, the Drift-Scale Coupled Processes (DST and TH Seepage) Models'' report, and the ''In-Drift Natural Convection and Condensation'' report. The specific objective of this study is to determine the rock-grain and rock-mass heat capacities for the geologic stratigraphy identified in the ''Mineralogic Model (MM3.0) Report'' (BSC 2004 [DIRS 170031], Table 1-1). This report provides estimates of the heat capacity for all stratigraphic layers except the Paleozoic, for which the mineralogic abundance data required to estimate the heat capacity are not available. The temperature range of interest in this analysis is 25 C to 325 C. This interval is broken into three separate temperature sub-intervals: 25 C to 95 C, 95 C to 114 C, and 114 C to 325 C, which correspond to the preboiling, trans-boiling, and postboiling regimes. Heat capacity is defined as the amount of energy required to raise the temperature of a unit mass of material by one degree (Nimick and Connolly 1991 [DIRS 100690], p. 5). The rock-grain heat capacity is defined as the heat capacity of the rock solids (minerals), and does not include the effect of water that exists in the rock pores. By comparison, the rock-mass heat capacity considers the heat capacity of both solids and pore water. For temperatures in the trans-boiling regime (95 C to 114 C), the additional energy required to vaporize the pore water is accounted for in the rock-mass heat capacity. The rock-grain heat capacities are intended to be used in models and analyses that explicitly account for the thermodynamic effects of the water within the rock porosity. The rock-mass heat capacities are intended to be used in models and analyses that do not explicitly account for these thermodynamic effects, particularly boiling. The term specific heat is often used synonymously with heat capacity; however, the latter term is used throughout this document.

A. Findikakis

2004-11-01

389

The Role of Iron and Dissolved Organic Carbon in the Absorption of Ultraviolet Radiation in Humic Lake Water  

Microsoft Academic Search

Absorption of solar ultraviolet radiation (UVR) in aquatic ecosystems is primarily controlled by dissolved organic carbon (DOC). The role of iron (Fe) has also been suggested to contribute to UVR attenuation either directly or by interactions with DOC. Here we present findings from three laboratory manipulations of Fe and DOC on changes to the dissolved UVR absorption (ad,320) in a

Kelly O. Maloney; Donald P. Morris; Carl O. Moses; Christopher L. Osburn

2005-01-01

390

Influence of cyclic fatigue in water on the load-bearing capacity of dental bridges made of zirconia  

Microsoft Academic Search

The humid atmosphere and permanent occurrence of chewing forces in the oral environment lead to degradation of ceramics used for prosthetic restorations. The aim of this in vitro study was to evaluate the influence of artificial aging on the load-bearing capacity of four-unit bridges, with both undamaged and predamaged zirconia frameworks. Additionally, different parameters for chewing simulation have been investigated

Philipp Kohorst; Marc Philipp Dittmer; Lothar Borchers; Meike Stiesch-Scholz

2008-01-01

391

Climate, energy and environmental care - Capacity building for relevant water research Experiences and lessons from UNESCO HELP  

Microsoft Academic Search

Climate change is real and poses a grimmer risk to livelihoods and the environment in particular in the developing world. Strategic capacity building and knowledge sharing structures are essential for generating positive sum solutions from these generally negative forces. Adoption and adaptation are main responses to climate change and environmental care but transaction costs are substantial. What knowledge is protected

Shahbaz Khan; Stefan Uhlenbrook

392

Corrosion Problems in Absorption Chillers  

ERIC Educational Resources Information Center

Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

Stetson, Bruce

1978-01-01

393

14 CFR 27.723 - Shock absorption tests.  

... 2014-01-01 false Shock absorption tests. 27.723 Section 27...Landing Gear § 27.723 Shock absorption tests. The landing inertia load factor and the reserve energy absorption capacity of the landing gear...

2014-01-01

394

14 CFR 27.723 - Shock absorption tests.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Shock absorption tests. 27.723 Section 27...Landing Gear § 27.723 Shock absorption tests. The landing inertia load factor and the reserve energy absorption capacity of the landing gear...

2013-01-01

395

14 CFR 27.723 - Shock absorption tests.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Shock absorption tests. 27.723 Section 27...Landing Gear § 27.723 Shock absorption tests. The landing inertia load factor and the reserve energy absorption capacity of the landing gear...

2012-01-01

396

14 CFR 29.723 - Shock absorption tests.  

... 2014-01-01 false Shock absorption tests. 29.723 Section 29...Landing Gear § 29.723 Shock absorption tests. The landing inertia load factor and the reserve energy absorption capacity of the landing gear...

2014-01-01

397

14 CFR 29.723 - Shock absorption tests.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Shock absorption tests. 29.723 Section 29...Landing Gear § 29.723 Shock absorption tests. The landing inertia load factor and the reserve energy absorption capacity of the landing gear...

2013-01-01

398

14 CFR 29.723 - Shock absorption tests.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Shock absorption tests. 29.723 Section 29...Landing Gear § 29.723 Shock absorption tests. The landing inertia load factor and the reserve energy absorption capacity of the landing gear...

2012-01-01

399

Future Performance of Ground-Based and Airborne Water-Vapor Differential Absorption Lidar. II. Simulations of the Precision of a Near-Infrared, High-Power System  

Microsoft Academic Search

Taking into account Poisson, background, amplifier, and speckle noise, we can simulate the precision of water-vapor measurements by using a 10-W average-power differential absorption lidar (DIAL) system. This system is currently under development at Hohenheim University, Germany, and at the American National Center for Atmospheric Research. For operation in the 940-nm region, a large set of measurement situations is described,

Volker Wulfmeyer; Craig Walther

2001-01-01

400

Cloud point extraction and graphite furnace atomic absorption spectrometry determination of manganese(II) and iron(III) in water samples  

Microsoft Academic Search

Cloud point extraction (CPE) was applied as a preconcentration step prior to graphite furnace atomic absorption spectrometry (GFAAS) determination of manganese(II) and iron(III) in water samples. After complexation with 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP), the analytes could be quantitatively extracted to the phase rich in the surfactant p-octylpolyethyleneglycolphenylether (Triton X-100) and be concentrated, then determined by GFAAS. The parameters affecting the extraction efficiency,

Pei Liang; Hongbo Sang; Zhimei Sun

2006-01-01

401

Performance test results of a lithium bromide-water absorption heat pump that uses low-temperature (60 deg C(140 deg F)) waste heat  

Microsoft Academic Search

An absorption heat pump for upgrading industrial waste heat to process steam temperatures was developed. The heat pump uses lithium bromide and water as the working fluids and is designed to operate with waste heat temperatures ranging from 60 to 100(0). Performance data from the 45-kW(t) prototype heat pump show good agreement with theoretical predictions. The successful operation of this

W. R. Huntley

1984-01-01

402

Rectal absorption and mucosal irritation of rectal gels containing buprenorphine hydrochloride prepared with water-soluble dietary fibers, xanthan gum and locust bean gum  

Microsoft Academic Search

Rectal gels prepared with water-soluble dietary fibers, xanthan gum and locust bean gum, were evaluated as a vehicle for the rectal administration of buprenorphine hydrochloride (BN-HCI) in rabbits. The maximum plasma concentration of buprenorphine (BN) gradually decreased with increase in the gum concentration. The values of the mean residence time (MRT0–2) increased in proportion to increasing gum concentration. The absorption

Kazunori Watanabe; Shigeru Yakou; Kozo Takayama; Koichi Isowa; Tsuneji Nagai

1996-01-01

403

Determination of beryllium in natural and waste waters using on-line flow-injection preconcentration by precipitation\\/dissolution for electrothermal atomic absorption spectrometry  

Microsoft Academic Search

A flow injection (FI) on-line precipitation–dissolution was developed for electrothermal atomic absorption spectrometry (ETAAS) determination of (ultra)trace amounts of beryllium in water samples. Beryllium was precipitated quantitatively with NH4OH+NH4Cl and collected in a knotted tube of Tygon without using a filter, while the other matrix components flowed downstream to waste. The precipitate was dissolved with nitric acid and a sub-sample

J. L. Burguera; M. Burguera; C. Rondón; P. Carrero; M. R. Brunetto; Y. Petit de Peña

2000-01-01

404

LASER MEDICINE: Effect of laser radiation absorption in water and blood on the optimal wavelength for endovenous obliteration of varicose veins  

NASA Astrophysics Data System (ADS)

This work examines laser radiation absorption in water and blood at the wavelengths that are used in endovenous laser treatment (EVLT): 0.81-1.06, 1.32, 1.47, 1.5 and 1.56 ?m. It is shown that the best EVLT conditions are ensured by 1.56-?m radiation. Analysis of published data suggests that even higher EVLT efficacy may be achieved at wavelengths of 1.68 and 1.7 ?m.

Zhilin, K. M.; Minaev, V. P.; Sokolov, Aleksandr L.

2009-08-01

405

Determination of trace heavy metals in waters by flame atomic absorption spectrometry after preconcentration with 2,4-dinitrophenyldiazoaminoazobenzene on Amberlite XAD-2  

Microsoft Academic Search

.  A new column, solid-phase extraction (SPE), preconcentration method was developed for determination of Cd, Co, and Cu ions\\u000a in natural water samples by flame atomic absorption spectrometry. The procedure is based on the retention of analytes in the\\u000a form of 2,4-dinitrophenyldiazoaminoazobenzene (DNDAA) complex on a mini column of DNDAA-XAD-2 resin. The effects of pH, eluent\\u000a type, eluent concentration, eluent volume,

Yongwen Liu; Yong Guo; Shuangming Meng; Feng Feng; Xijun Chang

2007-01-01

406

Preconcentration and determination of ultra trace amounts of palladium in water samples by dispersive liquid-liquid microextraction and graphite furnace atomic absorption spectrometry  

Microsoft Academic Search

A highly sensitive, simple and rapid method is presented for the determination of palladium using graphite furnace atomic\\u000a absorption spectrometry after its separation and preconcentration by dispersive liquid-liquid microextraction. Ultra traces\\u000a of Pd were extracted and preconcentrated in acidic water samples by using 2-amino-1-cyclohexene-1-dithiocarboxylic acid as\\u000a a suitable chelating agent, and carbon tetrachloride and acetone as extraction and disperser solvents,

Mojtaba Shamsipur; Majid Ramezani; Marzieh Sadeghi

2009-01-01

407

Column SolidPhase Extraction with 2-Acetylmercaptophenyldiazoaminoazobenzene (AMPDAA) Impregnated Amberlite XAD-4 and Determination of Trace Heavy Metals in Natural Waters by Flame Atomic Absorption Spectrometry  

Microsoft Academic Search

A column solid-phase extraction (SPE) preconcentration method was developed for the determination of Cd, Co, Cu, Ni and Zn ions in natural water samples by flame atomic absorption spectrometry. The procedure is based on the retention of analytes in the form of 2-acetylmercaptophenyldiazoaminoazobenzene (AMPDAA) complexes on a short column of AMPDAA-XAD-4 resin from buffered sample solution and subsequent elution with

Yongwen Liu; Yong Guo; Xijun Chang; Shuangming Meng; Dong Yang; Bingjun Din

2005-01-01

408

Continuum and magnetic dipole absorption of the water vapor--oxygen mixtures from 0.3 to 3.6 THz  

E-print Network

Continuum and magnetic dipole absorption of the water vapor--oxygen mixtures from 0.3 to 3.6 THz V 2008 In revised form 21 February 2008 Available online 18 March 2008 Keywords: Continuum IR THz Oxygen is reported for the far-IR region from 10 to 120 cm�1 (0.3­3.6 THz). The experiments were performed

409

Enhancement of the dissolution rate and gastrointestinal absorption of pranlukast as a model poorly water-soluble drug by grinding with gelatin.  

PubMed

The effect of grinding with gelatin on the dissolution behavior and gastrointestinal absorption of a poorly water-soluble drug was evaluated using the antiasthmatic agent, pranlukast, as a model poorly water-soluble drug. A ground pranlukast-gelatin mixture was prepared by grinding equal quantities of pranlukast and gelatin. In the dissolution testing, the dissolution rate of pranlukast in the suspension of the ground pranlukast-gelatin mixture under conditions of pH 3.0, 5.0 and 7.0 was markedly faster than that in the suspension of pranlukast. According to powder X-ray diffractometry (PXRD) and differential scanning calorimetry (DSC) analysis, the enhanced dissolution rate of pranlukast produced by grinding with gelatin was caused by changing the crystalline state of pranlukast into an amorphous state. In an animal experiment, the bioavailability of pranlukast following oral administration of the ground pranlukast-gelatin mixture to rats was threefold greater than that following administration of pranlukast. In the in vitro permeation experiment, the amount of permeated pranlukast through Caco-2 cell monolayers after application of the ground pranlukast-gelatin mixture was greater than that after application of pranlukast. These results suggest that the enhancement of the gastrointestinal absorption of pranlukast by grinding with gelatin is due to enhancement of the dissolution rate. Grinding a poorly water-soluble drug with gelatin is a useful method of enhancing its gastrointestinal absorption. PMID:17689212

Chono, Sumio; Takeda, Eri; Seki, Toshinobu; Morimoto, Kazuhiro

2008-01-22

410

Investigating Langmuir films at the air-water interface using a planar array infrared reflection-absorption spectrograph  

NASA Astrophysics Data System (ADS)

In this work, a new planar array infrared reflection-absorption spectrograph (PA-IRRAS) was developed to investigate a broad range of Langmuir films at the air-water interface. This instrument is capable of recording sample and reference spectra simultaneously with an optical setup that is the same as that of a single-beam instrument but splits the incident infrared beam into two sections on a plane mirror (H) or a water trough. With this design, the instrument could accommodate large infrared accessories, such as a water trough. In addition, water bands were subtracted to obtain a high quality spectrum for a poly(lactic acid) (PLA) Langmuir film on the water subphase with a resolution of about 8 cm-1 in 10.8 sec. With this instrument, two types of monolayer systems were studied; polymeric and lipid Langmuir films at the air-water interface. For the polymeric monolayer system, PA-IRRAS was used as a probe to follow the real-time conformational changes associated with intermolecular interactions of the polymer chains during the compression of the monolayers. It was found that the mixture of poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) (D/L) formed a stereocomplex when the mixed solution developed the two-dimensional monolayer at the air-water interface. The stereocomplexation occurred before film compression, indicating that there is no direct correlation between film compression and stereocomplexation. For the lipid monolayer system, PA-IRRAS was also used as a probe to investigate the origin of the disruption of a lipid monolayer upon protein adsorption at the air-water interface. Analysis of the time-resolved PA-IRRAS spectra revealed that Cu(II) ion-chelated DSIDA lipid monolayer (Cu 2+-DSIDA) was readily disrupted by myoglobin adsorption as demonstrated by a blue shift of 1.7 cm-1 and a lower intensity in the vas(CH2) stretch mode of the lipid monolayer over a period of five hours. To find the origin of the disruption of the lipid monolayer, a postulated model, employing a DSIDA monolayer-deposited ZnSe window, was investigated. An FT-IR spectroscopic study demonstrated that the Cu(II) ion formed stronger chelation with an iminodiacetatic acid (IDA) lipid head group than that formed with a Zn(II) ion. In addition, no distinct difference was observed in the secondary structures of myoglobin as myoglobin was adsorbed to Cu2+-DSIDA over a period of five hours. Dynamic light scattering (DLS) data revealed that, by the addition of Cu(II) or Zn(II) ion, lysozyme was rapidly aggregated and readily precipitated. However, the hydrodynamic volume of myoglobin was not responsive to the addition of Zn(II) ion. When Cu(II) ion was added, aggregation of myoglobin was sustained without precipitation over a period of five hours. Therefore, these results strongly suggest that the disruption of Cu2+-DSIDA lipid monolayer upon myoglobin adsorption is due to myoglobin aggregation, mediated by the chelated Cu(II) ion, rather than a conformational change in adsorbed myoglobin. Besides the above monolayer systems, PA-IRRAS is used for the rapid detection of a low concentration of aqueous species. The previous designs for a PA-IR spectrograph were not applicable to detect a low concentration of aqueous species due to the contribution from a stray light and high relative humidity (in the vicinity of 25-40%). To overcome this problem, newly designed PA-IRRAS optical setup was purged with dry nitrogen gas to keep the relative humidity at approximately 15%. In addition, baffles constructed from corrugated cardboard were placed throughout the optical setup to prevent any stray light from reaching the detector. The PA-IRRAS results obtained from poly(N-isopropylacrylamide) (PNIPAM) revealed that solutions down to a concentration of 0.005% w/w could be successfully studied. These results are quite remarkable, given the acquisition time of only 10 seconds and the direct overlap of the Amide I band of PNIPAM and the H-O-H stretch of H2O. (Abstract shortened by UMI.)

Kim, Young Shin

411

A new direct absorption tunable diode laser spectrometer for high precision measurement of water vapor in the upper troposphere and lower stratosphere.  

PubMed

We present a new instrument for the measurement of water vapor in the upper troposphere and lower stratosphere (UT?LS), the Harvard Herriott Hygrometer (HHH). HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell. The direct absorption technique provides a direct link between the depth of the observed absorption line and the measured water vapor concentration, which is calculated based on spectroscopic parameters in the HITRAN database. While several other tunable diode laser (TDL) instruments have been used to measure water vapor in the UT?LS, HHH is set apart by its use of an optical cell an order of magnitude smaller than those of other direct absorption TDLs in operation, allowing for a more compact, lightweight instrument. HHH is also unique in its integration into a common duct with the Harvard Lyman-? hygrometer, an independent photo-fragment fluorescence instrument which has been thoroughly validated over 19 years of flight measurements. The instrument was flown for the first time in the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) on NASA's WB-57 aircraft in spring, 2011, during which it demonstrated in-flight precision of 0.1 ppmv (1 s) with 1-sigma uncertainty of 5% ± 0.7 ppmv. Since the campaign, changes to the instrument have lead to improved accuracy of 5% ± 0.2 ppmv as demonstrated in the laboratory. During MACPEX, HHH successfully measured water vapor at concentrations from 3.5 to 600 ppmv in the upper troposphere and lower stratosphere. HHH and Lyman-?, measuring independently but under the same sampling conditions, agreed on average to within 1% at water vapor mixing ratios above 20 ppmv and to within 0.3 ppmv at lower mixing ratios. HHH also agreed with a number of other in situ water vapor instruments on the WB-57 to within their stated uncertainties, and to within 0.7 ppmv at low water. This agreement constitutes a significant improvement over past in situ comparisons, in which differences of 1.5-2 ppmv were routinely observed, and demonstrates that the accuracy of HHH is consistent with other instruments which use a range of detection methods and sampling techniques. PMID:23902086

Sargent, M R; Sayres, D S; Smith, J B; Witinski, M; Allen, N T; Demusz, J N; Rivero, M; Tuozzolo, C; Anderson, J G

2013-07-01

412

A new direct absorption tunable diode laser spectrometer for high precision measurement of water vapor in the upper troposphere and lower stratosphere  

NASA Astrophysics Data System (ADS)

We present a new instrument for the measurement of water vapor in the upper troposphere and lower stratosphere (UT/LS), the Harvard Herriott Hygrometer (HHH). HHH employs a tunable diode near-IR laser to measure water vapor via direct absorption in a Herriott cell. The direct absorption technique provides a direct link between the depth of the observed absorption line and the measured water vapor concentration, which is calculated based on spectroscopic parameters in the HITRAN database. While several other tunable diode laser (TDL) instruments have been used to measure water vapor in the UT/LS, HHH is set apart by its use of an optical cell an order of magnitude smaller than those of other direct absorption TDLs in operation, allowing for a more compact, lightweight instrument. HHH is also unique in its integration into a common duct with the Harvard Lyman-? hygrometer, an independent photo-fragment fluorescence instrument which has been thoroughly validated over 19 years of flight measurements. The instrument was flown for the first time in the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) on NASA's WB-57 aircraft in spring, 2011, during which it demonstrated in-flight precision of 0.1 ppmv (1 s) with 1-sigma uncertainty of 5% ± 0.7 ppmv. Since the campaign, changes to the instrument have lead to improved accuracy of 5% ± 0.2 ppmv as demonstrated in the laboratory. During MACPEX, HHH successfully measured water vapor at concentrations from 3.5 to 600 ppmv in the upper troposphere and lower stratosphere. HHH and Lyman-?, measuring independently but under the same sampling conditions, agreed on average to within 1% at water vapor mixing ratios above 20 ppmv and to within 0.3 ppmv at lower mixing ratios. HHH also agreed with a number of other in situ water vapor instruments on the WB-57 to within their stated uncertainties, and to within 0.7 ppmv at low water. This agreement constitutes a significant improvement over past in situ comparisons, in which differences of 1.5-2 ppmv were routinely observed, and demonstrates that the accuracy of HHH is consistent with other instruments which use a range of detection methods and sampling techniques.

Sargent, M. R.; Sayres, D. S.; Smith, J. B.; Witinski, M.; Allen, N. T.; Demusz, J. N.; Rivero, M.; Tuozzolo, C.; Anderson, J. G.

2013-07-01

413

Relationships between octan?1?ol\\/water partition coefficients, aqueous activity coefficients and reversed phase HPLC capacity factors of alkylbenzenes, chlorobenzenes, chloronaphthalenes and chlorobiphenyls  

Microsoft Academic Search

Linear relationships between logarithms of octan?1?ol\\/water partition coefficients (Kd,oct), aqueous activity coefficients (yaq) and extrapolated RP HPLC capacity factors (k‘w) are found for four types of aromatic hydrocarbons (alkylbenzenes and poly?chlorinated benzenes, ?naphthalenes and ?biphenyls).Both log K,d,oct and logk‘w increase with the increasing number of chlorine or methyl?ene substituents. These increases of log K,d,oct and log k‘w are proportional and

Antoon Opperhuizen

1987-01-01

414

Thermal conductivity, thermal effusivity, and specific heat capacity near the lower critical point of the binary liquid mixture n-butoxyethanol-water  

NASA Astrophysics Data System (ADS)

Experimental investigations on binary liquid mixtures near the critical mixing point are presently leading to a controversy about the anomaly in the thermal conductivity. A photopyroelectric technique is used to determine the thermal conductivity and the effusivity of the binary liquid mixture n-butoxyethanol-water at its critical concentration near the critical mixing point. It is proven that, contrary to previous reports, there is no critical enhancement in the thermal conductivity. The specific heat capacity is calculated from these results and compared with the results from measurements performed by adiabatic scanning calorimetry.

Pittois, S.; Van Roie, B.; Glorieux, C.; Thoen, J.

2004-07-01

415

Optimum hydrogen generation capacity and current density of the PEM-type water electrolyzer operated only during the off-peak period of electricity demand  

NASA Astrophysics Data System (ADS)

A requirement for widespread adoption of fuel cell vehicles in the transportation sector will be ready availability of pure hydrogen at prices that result in operating costs comparable to, or less than, that of gasoline internal combustion engine vehicles. The existing electrical power grid could be used as the backbone of the hydrogen infrastructure system in combination with water electrolyzers. A water electrolyzer can contribute to the load leveling by changing operational current density in accordance with the change of electricity demand. The optimum hydrogen generation capacity and current density of the polymer electrolyte membrane (PEM)-type water electrolyzer operated only during the off-peak period of electricity demand in respect of both the shortest time required for start and the higher efficiency of water electrolysis are obtained as 500 Nm 3 h -1 and 30 kA m -2, respectively. This PEM-type water electrolyzer could be used in the hydrogen refueling stations and energy storage systems constructed around hydrogen.

Oi, Tsutomu; Sakaki, Yoshinori

416

Combustion of black coal in the form of coal-water slurry in low-capacity boilers  

NASA Astrophysics Data System (ADS)

The present paper describes the examples of experimental and industrial implementation of technologies of flame-droplet combustion of the coal-water mixture in furnaces above a bed consisting of burning coal and in a swirling-type furnace chamber. For preparing coal-water fuel (CWF), Kuznetsk coals of G and D ranks, as well as tailings of coking coals, were used. The future prospect of both technologies of coal combustion has been shown from both economic and environmental standpoints.

Maltsev, L. I.; Kravchenko, I. V.; Lazarev, S. I.; Lapin, D. A.

2014-07-01

417

Start | View At a Glance | Author Index 220-1 Kinetics of Rapid Redox Processes at the Mineral/Water Interface Using Quick-Scanning X-Ray Absorption Spectroscopy  

E-print Network

at the Mineral/Water Interface Using Quick-Scanning X-Ray Absorption Spectroscopy (Q-XAS). See more from limited. Techniques such as electron paramagnetic resonance and Fourier transform infrared spectroscopies-situ synchrotron-based technique, quick scanning X-ray absorption spectroscopy (Q-XAS), at sub-second time scales

Sparks, Donald L.

418

Detection of the 3.3?m PAH Feature as well as Water Ice and HAC Absorption in z ˜ 2 ULIRGs  

NASA Astrophysics Data System (ADS)

We present preliminary results from the highest available signal-to-noise rest-frame 2-8 um spectra of z ˜ 2 ULIRGs. Our 10 targets are selected for their deep silicate absorption features based on previous shallower IRS spectra. The goal of this follow-up program is: 1) allow for a more accurate analysis of inner/hot dust continuum, 2) detecting the 3.3 um and 6.2 um PAH features, and 3) detecting molecular absorption features such as due to water ice and hydrocarbons (HACs). We find that the 3.4 um HAC absorption feature is observed in four sources, while the 3.05 um water ice feature is observed in three of the sources. The HAC detectability is higher and ice detectability lower than expected from local ULIRGs, but consistent with a more AGN-dominated sample such as this one. Where ice is detected, the ice-to-silicate ratio is somewhat lower than many local ULIRGs implying on average thinner ice mantles. One source shows the highest redshift reported detection of the 3.3 um PAH feature (along with a previously detected 6.2 um feature) whose strength is as expected for a starburst-dominated ULIRG.

Sajina, A.; Yan, L.; Spoon, H.; Fadda, D.

2009-10-01

419

Method development for the determination of fluorine in water samples via the molecular absorption of strontium monofluoride formed in an electrothermal atomizer  

NASA Astrophysics Data System (ADS)

The presence of fluorine (F) was detected via the rotational molecular absorption line of diatomic strontium-monofluoride (SrF) generated in the gas phase at 651.187 nm using high-resolution continuum source electrothermal atomic absorption spectrometry. Upon the addition of excess strontium (Sr) as the nitrate, the fluorine in the sample was converted to SrF in the gas phase of a graphite furnace. The effects on the accuracy, precision and sensitivity of variables such as the SrF wavelength, graphite furnace program, amount of Sr, coating of the graphite tube and platform with Zr and Ir and the use of a modifier were investigated and optimized. It was determined that there was no need to use a modifier or to cover the platform/tubes with Zr or Ir. Fluorine concentrations in various water samples (certified waste water, tap water, drinking water and mineral water) were determined using 20 ?g of Sr as the molecule-forming reagent and applying a maximum pyrolysis temperature of 800 °C and a molecule-forming temperature of 2200 °C with a heating rate of 2000 °C s- 1. Good linearity was maintained up to 0.1 ?g of F. The accuracy and precision of the method were tested by analyzing certified reference wastewater. The results were in good agreement with certified values, and the precision was satisfactory (RSD < 10%). The limit of detection and the characteristic mass for the method were 0.36 ng and 0.55 ng, respectively. Finally, the fluorine concentrations in several drinking water and mineral water samples taken from the market were determined. The results were in good agreement with the values supplied by the producers. No significant differences were found between the results from the linear calibration and standard addition techniques. The method was determined to be simple, fast, accurate and sensitive.

Ozbek, Nil; Akman, Suleyman

420

X-ray absorption spectra of nucleotides (AMP, GMP, and CMP) in liquid water solutions near the nitrogen K-edge  

NASA Astrophysics Data System (ADS)

The X-ray absorption of nucleotides (adenosine-5'-monophosphate, guanosine 5'-monophosphate, and cytidine 5'-monophosphate) are measured in both water solutions and thin solid films at X-ray energies near the nitrogen K-edge in the 'water-window' region. Each spectrum corresponds to the selective excitation of a nucleobase site in a nucleotide, and thus has features similar to the spectrum of the corresponding nucleobase. An additional new peak in the energy region of the nitrogen 1s ? ?* resonance is observed for each nucleotide. No significant difference between the water solutions and thin solid films is found, which might be attributable to the hydrophobic properties of a nucleobase in a nucleotide.

Ukai, Masatoshi; Yokoya, Akinari; Fujii, Kentaro; Saitoh, Yuji

2010-07-01

421

Variable Infiltration Capacity model (VIC) is a macro-scale energy and water balance model with lake and wetland  

E-print Network

) and soil heat flux · Water table depth (3 locations, 6-7 ft depth) Kankakee (Indiana, USA) outwash plain (VIC) Cold Land Process Model Updates, Global and Planetary Change, 38, 151-159, 2003. Sathulur, K., L North temperate peatlands play an important role in global climate partially due to the potential

Cherkauer, Keith

422

Coordination between water transport capacity, biomass growth, metabolic scaling and species stature in co-occurring shrub and tree species.  

PubMed

The significance of xylem function and metabolic scaling theory begins from the idea that water transport is strongly coupled to growth rate. At the same time, coordination of water transport and growth seemingly should differ between plant functional types. We evaluated the relationships between water transport, growth and species stature in six species of co-occurring trees and shrubs. Within species, a strong proportionality between plant hydraulic conductance (K), sap flow (Q) and shoot biomass growth (G) was generally supported. Across species, however, trees grew more for a given K or Q than shrubs, indicating greater growth-based water-use efficiency (WUE) in trees. Trees also showed slower decline in relative growth rate (RGR) than shrubs, equivalent to a steeper G by mass (M) scaling exponent in trees (0.77-0.98). The K and Q by M scaling exponents were common across all species (0.80, 0.82), suggesting that the steeper G scaling in trees reflects a size-dependent increase in their growth-based WUE. The common K and Q by M exponents were statistically consistent with the 0.75 of ideal scaling theory. A model based upon xylem anatomy and branching architecture consistently predicted the observed K by M scaling exponents but only when deviations from ideal symmetric branching were incorporated. PMID:25041417

Smith, Duncan D; Sperry, John S

2014-12-01

423

Polarization-Modulated Infrared Reflection Absorption Spectroscopic Studies of a Hydrogen-Bonding Network at the Air-Water Interface  

E-print Network

absorption spectroscopy (PM-IRRAS). The molecular structure and orientation of the 1:1 hydrogen- bonding. Compared to the previous IRRAS studies on the similar monolayers, the sensitivity of PM- IRRAS is obviously improved. PM-IRRAS will likely become a powerful analytical technique for the characterization of molecular

Rusell, K.C.

424

Matrix Interferences in Arsenic Determinations by Graphite Furnace Atomic Absorption Spectrometry: Recommendations for the Determination of Arsenic in Water Samples  

Microsoft Academic Search

The interferences of phosphate, sodium sulfate and chloride, aluminum nitrate, potassium chloride and selenous acid (singly and in combination) with the determination of arsenic by graphite furnace atomic absorption spectrometry were investigated. The arsenic signals were not only dependent on the phosphate concentration but also on the phosphate\\/arsenic ratio. Ashing curves (As signals as a function of ashing temperature) showed

D. Chakraborti; K. J. Irgolic; F. Adams

1984-01-01

425

Adsorption of Pb(II) on mesoporous activated carbons fabricated from water hyacinth using H3PO4 activation: Adsorption capacity, kinetic and isotherm studies  

NASA Astrophysics Data System (ADS)

Activated carbons with high mesoporosity and abundant oxygen-containing functional groups were prepared from water hyacinth using H3PO4 activation (WHAC) to eliminate Pb(II) in water. Characterizations of the WHAC were performed using Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The BET analysis showed that WHAC possesses a high mesoporosity (93.9%) with a BET surface area of 423.6 m2/g. The presence of oxygen-containing functional groups including hydroxyl, carbonyl, carboxyl and phosphate groups renders the WHAC a favorable adsorbent for Pb(II) with the maximum monolayer capacity (qm) 118.8 mg/g. The adsorption behavior follows pseudo-first order kinetic and Langmuir isotherm. The desorption study demonstrated that the WHAC could be readily regenerated using 0.1 M HCl (pH = 1.0). The desorbed WHAC could be reused at least six times without significant adsorption capacity reduction. The adsorption process was spontaneous and endothermic with ?G (-0.27, -1.13, -3.02, -3.62, -5.54, and -9.31 kJ/mol) and ?H (38.72 kJ/mol). Under the optimized conditions, a small amount of the adsorbent (1.0 g/L) could remove as much as 90.1% of Pb(II) (50 mg/L) in 20 min at pH 6.0 and temperature of 298 K. Therefore, the WHAC has a great potential to be an economical and efficient adsorbent in the treatment of lead-contaminated water.

Huang, Yang; Li, Shunxing; Chen, Jianhua; Zhang, Xueliang; Chen, Yiping

2014-02-01

426

Novel pectin-based nanoparticles prepared from nanoemulsion templates for improving in vitro dissolution and in vivo absorption of poorly water-soluble drug.  

PubMed

The purpose of this study was to improve in vitro dissolution and in vivo absorption of itraconazole (ITZ), a poorly water-soluble drug, by means of novel pectin-based nanoparticles prepared from nanoemulsion templates. Nanoemulsion templates were prepared by a high-pressure homogenization using pectin (i.e., 0.5-3.0%w/w low-methoxyl pectin (LMP), amidated low-methoxyl pectin (ALMP), or high-methoxyl pectin (HMP)) as an emulsifier and chloroform as an oil phase. HMP provided good oil-in-water emulsions with ITZ loaded in the oil phase. The chloroform in nanoemulsions was then removed to produce the suspensions of nanoparticles dispersed in water phase. After lyophilization, the dried core-shell nanoparticles with good properties in terms of redispersibility, dissolution, and stability were obtained. The alteration of ITZ crystallinity was clearly observed from powder X-ray diffractogram while no interaction between ITZ and pectin was found in the nanoparticles. The ITZ-loaded nanoparticles showed high percent drug dissolved, especially those prepared from HMP, and could maintain their good dissolution properties even after 6-month storage. The in vivo absorption study in fasted rats demonstrated that pectin-based nanoparticles prepared from nanoemulsion templates could improve absorption of ITZ, that is, 1.3-fold higher than the ITZ commercial product (p<0.05). Pectin type highly influenced the dissolution properties and also in vivo plasma profile. These findings suggested that HMP-based nanoparticles seem to be a promising formulation due to their high AUC(0-24h) and C(max). PMID:22885158

Burapapadh, Kanokporn; Takeuchi, Hirofumi; Sriamornsak, Pornsak

2012-10-01

427

Climatology and Dynamics of Water Vapor: Three Years of Sounding with the Differential Absorption Lidar on Mt. Zugspitze  

Microsoft Academic Search

Water vapor is the the most important greenhouse gas and its vertical distribution plays a major role for the radiative balance. In particular in the upper troposphere the radiative transfer is very sensitive to small changes of the water-vapor concentration. At the same time the water-vapor distribution strongly depends on atmospheric dynamics and, thus, can serve as a good tracer

Hannes Vogelmann; Thomas Trickl

2010-01-01

428

Initial results from a water vapor differential absorption lidar (DIAL) using a widely tunable amplified diode laser source  

Microsoft Academic Search

It is widely agreed that water vapor is one of the most important gasses in the atmosphere with regards to its role in local weather, global climate, and the water cycle. Especially with the growing concern for understanding and predicting global climate change, detailed data of water vapor distribution and flux and related feedback mechanisms in the lowest 3 km

Michael D. Obland; Amin R. Nehrir; Kevin S. Repasky; Joseph A. Shaw; John L. Carlsten

2007-01-01

429

New insights into the role of water in biological function: studying solvated biomolecules using terahertz absorption spectroscopy in conjunction with molecular dynamics simulations.  

PubMed

In life science, water is the ubiquitous solvent, sometimes even called the "matrix of life". There is increasing experimental and theoretical evidence that solvation water is not a passive spectator in biomolecular processes. New experimental techniques can quantify how water interacts with biomolecules and, in doing so, differs from "bulk" water. Terahertz (THz) absorption spectroscopy has turned out to be a powerful tool to study (bio)molecular hydration. The main concepts that have been developed in the recent years to describe the underlying solute-induced sub-picosecond dynamics of the hydration shell are discussed herein. Moreover, we highlight recent findings that show the significance of hydrogen bond dynamics for the function of antifreeze proteins and for molecular recognition. In all of these examples, a gradient of water motion toward functional sites of proteins is observed, the so-called "hydration funnel". By means of molecular dynamics simulations, we provide new evidence for a specific water-protein coupling as the cause of the observed dynamical heterogeneity. The efficiency of the coupling at THz frequencies is explained in terms of a two-tier (short- and long-range) solute-solvent interaction. PMID:25127002

Conti Nibali, Valeria; Havenith, Martina

2014-09-17