Acid deposition: a select review 1852-1990. 2. Effects on materials and health; abatement strategies and programmes

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S.; Raper, D.W.; Lee, D.S.; Heath, B.A.; Conlan, B.; King, H.J. (Manchester Metropolitan University, Manchester (United Kingdom). Atmospheric Research and Information Centre)

1993-10-01

Part 2 of this review is concerned with the impact of acid deposits and their precursors on materials and human health, and with the control technologies and programmes introduced as a consequence of the environmental impacts of acid deposition. 269 refs., 8 figs., 8 tabs.

Effects of acid deposition on ecosystems: Advances in the state of the science

Science.gov (United States)

Burns, Douglas A.; Fenn, Mark E.; Baron, Jill S.

2011-01-01

Chapter 2 focused on the environmental results of the ARP, presenting data from national monitoring networks on SO2 and NOx emissions, air quality, atmospheric deposition, surface water chemistry, and visibility. This chapter expands on this information by examining the most recent research into how ecosystems respond to acid deposition, especially the processes that control the recovery of ecosystems as acid deposition decreases. In Chapter 2, two general trends were discussed regarding the current recovery status of affected ecosystems: (1) these ecosystems are trending generally towards recovery, but improvements in ecosystem condition shown by surface water chemistry monitoring data thus far have been less than the improvements in deposition; and (2) ecosystem impacts and trends vary widely by geographic region, but the evidence of improvement is strongest and most evident in the Northeast. These trends are not uniform across the United States, however, and in some regions (e.g., central Appalachian Mountain region), trends in improved water quality are generally not evident. Despite the strong link in many areas between reduced emissions and reduced acidity of atmospheric deposition, the link is less clear between reduced acidity and recovery of the biological communities that live in aquatic and terrestrial ecosystems that have experienced deleterious effects from acid deposition. The recovery of these communities is proceeding at a slower pace than, for example, the improvements in stream and lake ANC would indicate. The goal of this chapter is to synthesize the science in a weightof-evidence manner to provide policy makers with tangible evidence and likely causative factors regarding ecosystem status and recovery patterns to date. This chapter serves as an update to the 2005 NAPAP RTC (NSTC, 2005), with an emphasis on scientific studies and monitoring since 2003, which was the last year for consideration of research results in the 2005 report. Several

Geological aspects of acid deposition

International Nuclear Information System (INIS)

Bricker, O.P.

1984-01-01

The general pattern of rain falling on the earth and reacting with the materials of the lithosphere (the weathering reactions so familiar to every beginning geology student) began soon after the earth was formed and has continued to the present. Anthropogenic additions to the natural acidic components of the atmosphere have increased since the time of the industrial revolution until they now rival or exceed those of the natural system. The severity of the environmental perturbations caused by these anthropogenic additions to the atmosphere has become a hotly debated topic in scientific forums and in the political arena. The six chapters in this book address various aspects of the acid deposition phenomenon from a geological perspective. It is hoped that the geological approach will be useful in bringing the problem more clearly into focus and may shed light on the geochemical processes that modify the chemical composition of acid deposition after it encounters and reacts with the materials of the lithosphere

The Contribution from Shipping Emissions to Air Quality and Acid Deposition in Europe

International Nuclear Information System (INIS)

Derwent, Richard G.; Stevenson, David S.; Doherty, Ruth M.; Cofala, Janusz; Mechler, Reinhard; Amann, Markus; Dentener, Frank J.

2005-01-01

A global three-dimensional Lagrangian chemistry-transport model STOCHEM is used to describe the European regional acid deposition and ozone air quality impacts along the Atlantic Ocean seaboard of Europe, from the SO 2 , NO x , VOCs and CO emissions from international shipping under conditions appropriate to the year 2000. Model-derived total sulfur deposition from international shipping reaches over 200 mg S m-2 yr-1 over the southwestern approaches to the British Isles and Brittany. The contribution from international shipping to surface ozone concentrations during the summertime, peaks at about 6 ppb over Ireland, Brittany and Portugal. Shipping emissions act as an external influence on acid deposition and ozone air quality within Europe and may require control actions in the future if strict deposition and air quality targets are to be met

Acidic deposition in California: findings from a program of monitoring and effects research

Energy Technology Data Exchange (ETDEWEB)

Takemoto, B.K.; Croes, B.E.; Brown, S.M.; Motallebi, N.; Westerdahl, F.D.; Margolis, H.G.; Cahill, B.T.; Mueller, M.D.; Holmes, J.R. [California Environmental Protection Agency, Sacramento, CA (United States). Research Division

1995-12-01

California`s 14-year, 25 million dollar acidic deposition program has studied the causes and effects of acidic air pollutants. In contrast to the eastern United States where sulfur-derived (S-derived) by-products from coal combustion dominate precipitation chemistry, nitrogen-derived (N-derived) acids predominate in wet and dry deposition in California. Adverse effects on the human lung have not been observed after short-term exposures to acidity, but extended exposures to ambient acidity may pose a chronic risk. No irreversible, adverse effects on surface waters in the Sierra Nevada mountain range or to the state`s forests have been found due to extent acidic inputs. The longer-term outlook for forests is less certain because the impacts observed elsewhere occurred after decades of S and N deposition, but at lower ambient ozone levels. Ozone is the major air pollutant stressor for forests, but atmospheric N has the potential to cause adverse changes in soil nutrient cycling. Impacts on man-made materials in southern California (e.g. galvanized steel) were found to be minor. While California does not have an ambient air quality standard for acidic air pollutants, emission of precursors have declined since the 1960s due to changes in industrial practices, improvements in technology and adoption of control measures for ozone. Lowering emission from motor vehicles will be emphasized to prevent future increases in N deposition. 67 refs., 4 figs., 2 tabs.

Effects of deposition time in chemically deposited ZnS films in acidic solution

Energy Technology Data Exchange (ETDEWEB)

Haddad, H.; Chelouche, A., E-mail: azeddinechelouche@gmail.com; Talantikite, D.; Merzouk, H.; Boudjouan, F.; Djouadi, D.

2015-08-31

We report an experimental study on the synthesis and characterization of zinc sulfide (ZnS) single layer thin films deposited on glass substrates by chemical bath deposition technique in acidic solution. The effect of deposition time on the microstructure, surface morphology, optical absorption, transmittance, and photoluminescence (PL) was investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), UV-Vis–NIR spectrophotometry and photoluminescence (PL) spectroscopy. The results showed that the samples exhibit wurtzite structure and their crystal quality is improved by increasing deposition time. The latter, was found to affect the morphology of the thin films as showed by SEM micrographs. The optical measurements revealed a high transparency in the visible range and a dependence of absorption edge and band gap on deposition time. The room temperature PL spectra indicated that all ZnS grown thin films emit a UV and blue light, while the band intensities are found to be dependent on deposition times. - Highlights: • Single layer ZnS thin films were deposited by CBD in acidic solution at 95 °C. • The effect of deposition time was investigated. • Coexistence of ZnS and ZnO hexagonal structures for time deposition below 2 h • Thicker ZnS films were achieved after monolayer deposition for 5 h. • The highest UV-blue emission observed in thin film deposited at 5 h.

Low-Vacuum Deposition of Glutamic Acid and Pyroglutamic Acid: A Facile Methodology for Depositing Organic Materials beyond Amino Acids.

Science.gov (United States)

Sugimoto, Iwao; Maeda, Shunsaku; Suda, Yoriko; Makihara, Kenji; Takahashi, Kazuhiko

2014-01-01

Thin layers of pyroglutamic acid (Pygl) have been deposited by thermal evaporation of the molten L-glutamic acid (L-Glu) through intramolecular lactamization. This deposition was carried out with the versatile handmade low-vacuum coater, which was simply composed of a soldering iron placed in a vacuum degassing resin chamber evacuated by an oil-free diaphragm pump. Molecular structural analyses have revealed that thin solid film evaporated from the molten L-Glu is mainly composed of L-Pygl due to intramolecular lactamization. The major component of the L-Pygl was in β-phase and the minor component was in γ-phase, which would have been generated from partial racemization to DL-Pygl. Electron microscopy revealed that the L-Glu-evaporated film generally consisted of the 20 nm particulates of Pygl, which contained a periodic pattern spacing of 0.2 nm intervals indicating the formation of the single-molecular interval of the crystallized molecular networks. The DL-Pygl-evaporated film was composed of the original DL-Pygl preserving its crystal structures. This methodology is promising for depositing a wide range of the evaporable organic materials beyond amino acids. The quartz crystal resonator coated with the L-Glu-evaporated film exhibited the pressure-sensing capability based on the adsorption-desorption of the surrounding gas at the film surface.

Microbial activity in an acid resin deposit: Biodegradation potential and ecotoxicology in an extremely acidic hydrocarbon contamination

International Nuclear Information System (INIS)

Kloos, Karin; Schloter, Michael; Meyer, Ortwin

2006-01-01

Acid resins are residues produced in a recycling process for used oils that was in use in the forties and fifties of the last century. The resin-like material is highly contaminated with mineral oil hydrocarbons, extremely acidic and co-contaminated with substituted and aromatic hydrocarbons, and heavy metals. To determine the potential for microbial biodegradation the acid resin deposit and its surroundings were screened for microbial activity by soil respiration measurements. No microbial activity was found in the core deposit. However, biodegradation of hydrocarbons was possible in zones with a lower degree of contamination surrounding the deposit. An extreme acidophilic microbial community was detected close to the core deposit. With a simple ecotoxicological approach it could be shown that the pure acid resin that formed the major part of the core deposit, was toxic to the indigenous microflora due to its extremely low pH of 0-1. - Acidity is the major toxic factor of the extremely hydrophobic and acidic mixed contamination found in an acid resin deposit

Acid formic effect in zinc coatings obtained by galvanostatic deposition

International Nuclear Information System (INIS)

Lopes, C.; David, M.; Souza, E.C.

2016-01-01

Zinc deposits obtained from electrodeposition is widely used for the purpose of protecting steel substrates from corrosion. They are generally added to Zn deposition bath many additives for improving certain characteristics of the deposit. As far as is known there is no information in literature about the effect of formic acid in corrosion resistance of a Zn deposit. Because it is an acid additive, it has the use of cyclohexylamine, in order for the electrolytic bath continue with a pH equal to the one used commercially, around 5. The main goal of this study is analyze the effect of the formic acid addition in the corrosion resistance of an Zn electrodeposition obtained by galvanostatic deposition. The results obtained by performance tests, cyclic voltammetry and X-ray diffraction showed that the formic acid addition may be promising in combating the corrosion of materials. (author)

Acidic deposition and its effects on forest productivity: a review of the present state of knowledge, research activities, and information needs

Energy Technology Data Exchange (ETDEWEB)

Pinkerton, J.E.

1981-01-01

The present state of knowledge with regard to acid deposition is reviewed. Sources include the literature and direct contact with persons responsible for carrying out all completed, ongoing, and planned research activities, national and international, related to acidic deposition and its effects, with emphasis on forest productivity. In addition, a list of information needs in seven areas was developed, these include: a characterization of forest soils to define their sensitivity to acidic deposition; effects on forest soil chemical and biological processes; development of improved dry deposition measurement methods; changes in precipitation composition due to forest canopies; more extensive monitoring of acidic deposition in industry owned forest lands; expansion of long-term greenhouse and controlled field experiments; and the relationship of acidic deposition and intensive forestry management practices. 85 references. (MDF)

Aquatic chemistry of acid deposition

Energy Technology Data Exchange (ETDEWEB)

Stumm, W; Sigg, L; Schnoor, J L

1987-01-01

The occurrence of acid precipitation in many regions of the Northern hemisphere is a consequnece of human interference in the cycles that unite land, water and atmosphere. The oxidation of carbon, sulfur and nitrogen, resulting mostly from fossil fuel burning, rivals oxidation processes induced by photosynthesis and respiration and disturbs redox conditions in the atmosphere. The paper discusses oxidation-reduction reactions, particularly those involving atmospheric pollutants that are important in the formation of acid precipitation. Topics covered are: a stoichiometric model of acid rain formation; sulfur dioxide and ammonia adsorption; acid neutralizing capacity. The paper concludes that explanations of simple chemical equilibria between gases and water aid our understanding of how acidifying gases become dissolved in cloud water, in droplets of falling rain, or in fog. Rigorous definitions of base- or acid-neutralizing capacities are prerequisites to measuring and interpreting residual acidity in dry and wet deposition and for assessing the disturbance caused by the transfer of acid to terrestrial and aquatic ecosystems. 20 references.

Acid deposition study in the Asian countries

Energy Technology Data Exchange (ETDEWEB)

Soon, Ting-Kueh [Tunku Abdul Rahman College, Kuala Lumpur (Malaysia); Lau, Wai-Yoo [Malaysian Scientific Association, Kuala Lumpur (Malaysia)

1996-12-31

The Association of South East Asian Nations or ASEAN is a regional association of seven countries, namely Indonesia, Malaysia, Philippines, Singapore, Thailand, Brunei and Vietnam, located at the south eastern part of the Asian continent. Together with the East Asian States of Japan, China, Korea and Taiwan, this part of the world is experiencing rapid economic growth, especially in the last decade. Rapid industrialization has resulted in an increased demand for energy in the manufacturing and transport sectors, and also for infrastructure development. This has led to a significant increase in gaseous emissions and a corresponding increase in atmospheric acidity. Acid deposition study in the ASEAN countries began in the mid-70s when Malaysia first started her acid rain monitoring network in 1976. This was followed closely by Singapore and the other ASEAN countries in the 80s. By now all ASEAN countries have their own acid rain monitoring networks with a number of these countries extending the monitoring to dry deposition as well.

Effects of acidic deposition on forest and aquatic ecosystems in New York State

Energy Technology Data Exchange (ETDEWEB)

Driscoll, Charles T.; Driscoll, Kimberley M.; Mitchell, Myron J.; Raynal, Dudley J

2003-06-01

Elevated inputs of acidic deposition have deleterious effects on forest and aquatic ecosystems in New York. - Acidic deposition is comprised of sulfuric and nitric acids and ammonium derived from atmospheric emissions of sulfur dioxide, nitrogen oxides, and ammonia, respectively. Acidic deposition has altered soil through depletion of labile pools of nutrient cations (i.e. calcium, magnesium), accumulation of sulfur and nitrogen, and the mobilization of elevated concentrations of inorganic monomeric aluminum to soil solutions in acid-sensitive areas. Acidic deposition leaches essential calcium from needles of red spruce, making this species more susceptible to freezing injury. Mortality among sugar maples appears to result from deficiencies of nutrient cations, coupled with other stresses such as insect defoliation or drought. Acidic deposition has impaired surface water quality in the Adirondack and Catskill regions of New York by lowering pH levels, decreasing acid-neutralizing capacity, and increasing aluminum concentrations. Acidification has reduced the diversity and abundance of aquatic species in lakes and streams. There are also linkages between acidic deposition and fish mercury contamination and eutrophication of estuaries.

The nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Kurbonov, A.S.; Mamatov, E.D.; Suleymani, M.; Borudzherdi, A.; Mirsaidov, U.M.

2011-01-01

Present article is devoted to nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit of Tajikistan. The obtaining of boric acid from pre backed danburite concentrate by decomposition of nitric acid was studied. The chemical composition of danburite concentrate was determined. The laboratory study of danburite leaching by nitric acid was conducted. The influence of temperature, process duration, nitric acid concentration on nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit was studied as well. The optimal conditions of nitric acid decomposition of calcined danburite concentrate of Ak-Arkhar Deposit, including temperature, process duration, nitric acid concentration and particle size were proposed.

Effects of acid deposition on microbial processes in natural waters

International Nuclear Information System (INIS)

Gilmour, C.C.

1992-01-01

Biogeochemical processes mediated by microorganisms are not adversely affected by the acidification of natural waters to the same extent as are the life cycles of higher organisms. Basic processes, e.g., primary production and organic matter decomposition, are not slowed in moderately acidified systems and do not generally decline above a pH of 5. More specifically, the individual components of the carbon, nitrogen, and sulfur cycles are, with few exceptions, also acid resistant. The influence of acid deposition on microbial processes is more often stimulation of nitrogen and sulfur cycling, often leading to alkalinity production, which mitigates the effect of strong acid deposition. Bacterial sulfate reduction and denitrification in sediments are two of the major processes that can be stimulated by sulfate and nitrate deposition, respectively, and result in ANC (acid-neutralizing capacity) generation. One of the negative effects of acid deposition is increased mobilization and bioaccumulation of some metals. Bacteria appear to play an important role, especially in mercury cycling, with acidification leading to increased bacterial methylation of mercury and subsequent bioaccumulation in higher organisms

Simulated dry deposition of nitric acid near forest edges

NARCIS (Netherlands)

DeJong, JJM; Klaassen, W; Jong, J.J.M. de

1997-01-01

Dry deposition is simulated to understand and generalize observations of enhanced deposition of air pollution near forest edges. Nitric acid is taken as an example as its deposition velocity is often assumed to be determined by turbulent transport only. The simulations are based on the

Intensified Vegetation Water Use due to Soil Calcium Leaching under Acid Deposition

Science.gov (United States)

Lanning, M.; Wang, L.; Scanlon, T. M.; Vadeboncoeur, M. A.; Adams, M. B.; Epstein, H. E.; Druckenbrod, D.

2017-12-01

Despite the important role vegetation plays in the global water cycle, the exact controls of vegetation water use, especially the role of soil biogeochemistry, remain elusive. Nitrate and sulfate deposition from fossil fuel burning has caused significant soil acidification, leading to the leaching of soil base cations. From a physiological perspective, plants require various soil cations as signaling and regulatory ions as well as integral parts of structural molecules; a depletion of soil cations can cause reduced productivity and abnormal responses to environmental change. A deficiency in calcium could also potentially prolong stomatal opening, leading to increased transpiration until enough calcium had been acquired to stimulate stomatal closure. Based on the plant physiology and the nature of acidic deposition, we hypothesize that depletion of the soil calcium supply, induced by acid deposition, would intensify vegetation water use at the watershed scale. We tested this hypothesis by analyzing a long-term and unique data set (1989-2012) of soil lysimeter data along with stream flow and evapotranspiration data at the Fernow Experimental Forest. We show that depletion of soil calcium by acid deposition can intensify vegetation water use ( 10% increase in evapotranspiration and depletion in soil water) for the first time. These results are critical to understanding future water availability, biogeochemical cycles, and surficial energy flux and may help reduce uncertainties in terrestrial biosphere models.

Acidic deposition along the Appalachian Trail corridor and its effects on acid-sensitive terrestrial and aquatic resources

Science.gov (United States)

Lawrence, Gregory B.; Sullivan, Timothy J.; Burns, Douglas A.; Bailey, Scott W.; Cosby, Bernard J.; Dovciak, Martin; Ewing, Holly A.; McDonnell, Todd C.; Minocha, Rakesh; Riemann, Rachel; Quant, Juliana; Rice, Karen C.; Siemion, Jason; Weathers, Kathleen C.

2015-01-01

The Appalachian National Scenic Trail (AT), a unit of the National Park Service (NPS), spans nearly 2,200 miles from Georgia to Maine, encompassing a diverse range of ecosystems. Acidic deposition (acid rain) threatens the AT’s natural resources. Acid rain is a result of sulfur (S) and nitrogen (N) compounds produced from fossil fuel combustion, motor vehicles, and agricultural practices. The AT is particularly vulnerable to S and N because it passes along ridgetops that receive higher levels of acid rain than lower valley terrain, and these ridges are often underlain by bedrock with minimal ability to buffer acidic inputs. Further, there are numerous S and N emission sources across the region. In the environment, acidic deposition can lower the pH of streams and soils which can ultimately affect fish, invertebrates, and vegetation that inhabit these areas. To address this concern, the MegaTransect Deposition Effects Study evaluated the condition and sensitivity of the AT corridor with respect to acidic deposition, and defined air pollution thresholds (critical and target loads) and recovery rates. Findings indicate that additional S emission

Phenolic acids as bioindicators of fly ash deposit revegetation.

Science.gov (United States)

Djurdjević, L; Mitrović, M; Pavlović, P; Gajić, G; Kostić, O

2006-05-01

The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the "Nikola Tesla-A" thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges (ranging from 1-80%). Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids (38.07-185.16 microg/g of total phenolics and 4.12-27.28 microg/g of phenolic acids) in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. Ash samples contained high amounts of ferulic, vanillic, and p-coumaric acid, while the content of both p-hydroxybenzoic and syringic acid was relatively low. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

High frequency and large deposition of acid fog on high elevation forest.

Science.gov (United States)

Igawa, Manabu; Matsumura, Ko; Okochi, Hiroshi

2002-01-01

We have collected and analyzed fogwater on the mountainside of Mt. Oyama (1252 m) in the Tanzawa Mountains of Japan and observed the fog event frequency from the base of the mountain with a video camera. The fog event frequency increased with elevation and was observed to be present 46% of the year at the summit. The water deposition via throughfall increased with elevation because of the increase in fogwater interception and was about twice that via rain at the summit, where the air pollutant deposition via throughfall was several times that via rainwater. The dry deposition and the deposition via fogwater were dominant factors in the total ion deposition at high elevation sites. In a fog event, nitric acid, the major acid component on the mountain, is formed during the transport of the air mass from the base of the mountain along the mountainside, where gases including nitric acid deposit and are scavenged by fogwater. Therefore, high acidity caused by nitric acid and relatively low ion strength are observed in the fogwater at high elevation sites.

Assessing future economic impacts of acidic deposition on the recreational fishery of eastern Canada

International Nuclear Information System (INIS)

1990-01-01

A study was carried out to assess the socio-economic impacts and net economic value effects related to potential reduction in acidic deposition on the sports fishery of eastern Canada. Impacts and net economic effects that would have occurred from 1950 to 1985 if emission/deposition controls were in place are measured. Impacts and net economic effects that will occur from 1986 to 2021 if controls are put in place in the future are also measured. The study incorporated the latest data describing the relationship of acidic deposition to lake pH levels and ultimate impact on fish survival, and applies a spatial analysis system to model changes in sport fish availability with respect to pH changes and fish survival responses. It was found that if emission controls were put in place beginning in 1950 the Canadian economy would have accrued $4.3 billion in net economic value from 1950 to 1985 inclusive. The 1986 value of the historical stream of losses that occurred because controls were not put in place is $24 billion assuming a 10% rate of return. If controls were put in place in the future, net economic value to Canada due to increased angler activity would be $4.2 billion for the period 1986-2021. The value in 1986 would be $925 million. 9 figs., 34 tabs

Expanding atmospheric acid deposition in China from the 1990s to the 2010s

Science.gov (United States)

Yu, Haili; Wang, Qiufeng

2017-04-01

Atmospheric acid deposition is considered a global environmental issue. China has been experiencing serious acid deposition, which is anticipated to be more serious with the country's economic development and increasing consumption of fossil fuels in recent decades. By collecting nationwide data on pH and concentrations of sulfate (SO42-) and nitrate (NO3-) in precipitation between 1980 and 2014 in China, we explored the spatiotemporal variations of precipitation acid deposition (bulk deposition) and their influencing factors. Our results showed that average precipitation pH values were 4.86 and 4.84 in the 1990s and 2010s, respectively. This suggests that precipitation acid deposition in China has not seriously changes. Average SO42- deposition declined from 30.73 to 28.61 kg S ha-1 yr-1 but average NO3- deposition increased from 4.02 to 6.79 kg N ha-1 yr-1. Specifically, the area of severe precipitation acid deposition in southern China has shrunk to some extent as a result of decreasing pollutant emissions, whereas the area of moderate precipitation acid deposition has expanded in northern China, associated with rapid industrial and transportation development. Significant positive correlations have been found between precipitation acid deposition, energy consumption, and rainfall. Our findings provide a comprehensive evaluation of the spatiotemporal dynamics of precipitation acid deposition in China over past three decades, and confirm the idea that strategies implemented to save energy and reduce pollutant emissions in China have been effective in alleviating precipitation acid deposition. These findings might be used to demonstrate how developing countries could achieve economic development and environmental protection through the implementation of advanced technologies to reduce pollutant emissions.

Declining acidic deposition begins reversal of forest-soil acidification in the northeastern U.S

Science.gov (United States)

Gregory B. Lawrence; Paul W. Hazlett; Ivan J. Fernandez; Rock Ouimet; Scott W. Bailey; Walter C. Shortle; Kevin T. Smith; Michael R. Antidormi

2015-01-01

Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been...

Do uric acid deposits in zooxanthellae function as eye-spots?

Directory of Open Access Journals (Sweden)

Hiroshi Yamashita

2009-07-01

Full Text Available The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100-150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot.

Do uric acid deposits in zooxanthellae function as eye-spots?

Science.gov (United States)

Yamashita, Hiroshi; Kobiyama, Atsushi; Koike, Kazuhiko

2009-07-17

The symbiosis between zooxanthellae (dinoflagellate genus Symbiodinium) and corals is a fundamental basis of tropical marine ecosystems. However the physiological interactions of the hosts and symbionts are poorly understood. Recently, intracellular crystalline deposits in Symbiodinium were revealed to be uric acid functioning for nutrient storage. This is the first exploration of these enigmatic crystalline materials that had previously been misidentified as oxalic acid, providing new insights into the nutritional strategies of Symbiodinium in oligotrophic tropical waters. However, we believe these deposits also function as eye-spots on the basis of light and electron microscopic observations of motile cells of cultured Symbiodinium. The cells possessed crystalline deposit clusters in rows with each row 100-150 nm thick corresponding to 1/4 the wavelength of light and making them suitable for maximum wave interference and reflection of light. Crystalline clusters in cells observed with a light microscope strongly refracted and polarized light, and reflected or absorbed short wavelength light. The facts that purines, including uric acid, have been identified as the main constituents of light reflectors in many organisms, and that the photoreceptor protein, opsin, was detected in our Symbiodinium strain, support the idea that uric acid deposits in Symbiodinium motile cells may function as a component of an eye-spot.

Image analysis of epicuticular damage to foliage caused by dry deposition of the air pollutant nitric acid.

Science.gov (United States)

Padgett, Pamela E; Parry, Sally D; Bytnerowicz, Andrzej; Heath, Robert L

2009-01-01

Nitric acid vapor is produced by the same photochemical processes that produce ozone. In the laboratory, concentrated nitric acid is a strong acid and a powerful oxidant. In the environment, where the concentrations are much lower, it is an innocuous source of plant nitrogen. As an air pollutant, which mode of action does dry deposition of nitric acid follow? We investigated the effects of dry deposition of nitric acid on the foliage of four tree species native to the western United States. A novel controlled environment, fumigation system enabled a four-week exposure at concentrations consistent with ambient diurnal patterns. Scanning electron microscopy and automated image analysis revealed changes in the epicuticular wax layer during fumigation. Exposure to nitric acid resulted in a reproducible suite of damage symptoms that increased with increasing dose. Each tree species tested exhibited a unique set of damage features, including cracks, lesions, and conformation changes to epicuticular crystallite structures. Dry deposition of atmospheric nitric acid caused substantial perturbation to the epicuticular surface of all four tree species investigated, consistent with the chemical oxidation of epicuticular waxes. Automated image analysis eliminated many biases that can trouble microscopy studies. Trade names and commercial enterprises or products are mentioned solely for information. No endorsements by the U.S. Department of Agriculture are implied.

Phenolic acids as bioindicators of fly ash deposit revegetation

Energy Technology Data Exchange (ETDEWEB)

L. Djurdjevic; M. Mitrovic; P. Pavlovic; G. Gajic; O. Kostic [Institute for Biological Research ' Sinisa Stankovic,' Belgrade (Serbia and Montenegro). Department of Ecology

2006-05-15

The floristic composition, the abundance, and the cover of pioneer plant species of spontaneously formed plant communities and the content of total phenolics and phenolic acids, as humus constituents, of an ash deposit after 7 years of recultivation were studied. The restoration of both the soil and the vegetation on the ash deposits of the 'Nikola Tesla-A' thermoelectric power plant in Obrenovac (Serbia) is an extremely slow process. Unfavorable physical and chemical characteristics, the toxicity of fly ash, and extreme microclimatic conditions prevented the development of compact plant cover. The abundance and cover of plants increased from the central part of the deposit towards its edges. Festuca rubra L., Crepis setosa Hall., Erigeron canadensis L., Cirsium arvense (L.) Scop., Calamagrostis epigeios (L.) Roth., and Tamarix gallica L. were the most abundant species, thus giving the highest cover. Humus generated during the decomposition process of plant remains represents a completely new product absent in the ash as the starting material. The amount of total phenolics and phenolic acids in fly ash increased from the center of the deposit towards its edges in correlation with the increase in plant abundance and cover. The presence of phenolic acids indicates the ongoing process of humus formation in the ash, in which the most abundant pioneer plants of spontaneously formed plant communities play the main role. Phenolic compounds can serve as reliable bioindicators in an assessment of the success of the recultivation process of thermoelectric power plants' ash deposits.

Handbook of methods for acid-deposition studies. Laboratory analyses for soil chemistry

International Nuclear Information System (INIS)

Blume, L.J.; Schumacher, P.W.; Schaffer, K.A.; Cappo, K.A.; Papp, M.L.

1990-09-01

The handbook describes methods used to process and analyze soil samples. It is intended as a guidance document for groups involved in acid deposition monitoring activities similar to those implemented by the Aquatic Effects Research Program of the National Acid Precipitation Assessment Program. These methods were developed for use in the Direct/Delayed Response Project, a component project of the Aquatic Effects Research Program within the Office of Ecological Processes and Effects Research. The program addresses the following issues relating to the effects of acid deposition on aquatic ecosystems: The extent and magnitude of past change; The change to be expected in the future under various deposition scenarios; The maximum rates of deposition below which further change is not expected; and The rate of change or recovery of aquatic ecosystems if deposition rates are decreased. Chemical and physical parameters were measured during the Direct/Delayed Response Project and are described in the document

[Current situation and impact factors of acid deposition in main cites of Shandong Province].

Science.gov (United States)

Jia, Hong-yu; Zhang, Qiao-xian; Deng, Hong-bing; Zhao, Jing-zhu; Mu, Jin-bo; Zhang, De-zhi

2006-12-01

Based on the monitoring data for years in Shandong Province, current situation of acid rain in every city was assessed, and the temporal distribution of the dry, wet and total sulfur deposition in Jinan and Qingdao were studied. The results showed that Qingdao which had the largest precipitation acidity was the single city whose annul average precipitation pH was below 5. 60. The precipitation acidities in the main cities of Shandong Province were in a descent tendency. The total sulfur desposition in Jinan and Qingdao was basically stable or in a descent tendency, but also reached 10 t/(km(2)x a) or so. Among the total sulfur deposition flux, the dry deposition of sulfur had the greater contribution, and the contribution of SO2 dry deposition was higher than that of SO42- dry deposition. By analyzing the relation between the precipitation acidity and the SO2 discharge intensity, soil acidity and meteorological condition, the impact factors of acid precipitation in the cities of Shandong Province were revealed.

Characterization of the acidic cold seep emplaced jarositic Golden Deposit, NWT, Canada, as an analogue for jarosite deposition on Mars

Science.gov (United States)

Battler, Melissa M.; Osinski, Gordon R.; Lim, Darlene S. S.; Davila, Alfonso F.; Michel, Frederick A.; Craig, Michael A.; Izawa, Matthew R. M.; Leoni, Lisa; Slater, Gregory F.; Fairén, Alberto G.; Preston, Louisa J.; Banerjee, Neil R.

2013-06-01

Surficial deposits of the OH-bearing iron sulfate mineral jarosite have been observed in several places on Mars, such as Meridiani Planum and Mawrth Vallis. The specific depositional conditions and mechanisms are not known, but by comparing martian sites to analogous locations on Earth, the conditions of formation and, thus, the martian depositional paleoenvironments may be postulated. Located in a cold semi-arid desert ˜100 km east of Norman Wells, Northwest Territories, Canada, the Golden Deposit (GD) is visible from the air as a brilliant golden-yellow patch of unvegetated soil, approximately 140 m × 50 m. The GD is underlain by permafrost and consists of yellow sediment, which is precipitating from seeps of acidic, iron-bearing groundwater. On the surface, the GD appears as a patchwork of raised polygons, with acidic waters flowing from seeps in troughs between polygonal islands. Although UV-Vis-NIR spectral analysis detects only jarosite, mineralogy, as determined by X-ray diffraction and inductively coupled plasma emission spectrometry, is predominantly natrojarosite and jarosite, with hydronium jarosite, goethite, quartz, clays, and small amounts of hematite. Water pH varies significantly over short distances depending on proximity to acid seeps, from 2.3 directly above seeps, to 5.7 several m downstream from seeps within the deposit, and up to 6.5 in ponds proximal to the deposit. Visual observations of microbial filament communities and phospholipid fatty acid analyses confirm that the GD is capable of supporting life for at least part of the year. Jarosite-bearing sediments extend beneath vegetation up to 70 m out from the deposit and are mixed with plant debris and minerals presumably weathered from bedrock and glacial till. This site is of particular interest because mineralogy (natrojarosite, jarosite, hematite, and goethite) and environmental conditions (permafrost and arid conditions) at the time of deposition are conceivably analogous to jarosite

Potential research money available from the Acid Deposition Program and Alberta Environment

International Nuclear Information System (INIS)

Primus, C.L.

1992-01-01

It is exceedingly difficult to demonstrate definitive long-term changes in animal health as a result of acid-forming emissions from sour gas wells. A summary is presented of current research in Alberta, followed by the potential for research funding by the Alberta Government/Industry Acid Deposition Program (ADRP). The Alberta Environment research budget consists of four programs in addition to the ADRP: acid deposition effects research in the Athabasca oil sands; western and northern Canada long-range transport of air pollutants; departmental monitoring; and inhalation toxicology and animal health. Animal health research, although a component of the acid deposition issue, is beyond the mandate of Alberta Environment, and the ADRP members committee does not forsee becoming involved in the long-term and complex research required to address the effects of acid-forming emissions on livestock. Funds for additional animal health research must come from other government departments and agencies whose mandate covers this area

Differences in functional traits between invasive and native Amaranthus species under simulated acid deposition with a gradient of pH levels

Science.gov (United States)

Wang, Congyan; Wu, Bingde; Jiang, Kun; Zhou, Jiawei

2018-05-01

Co-occurring invasive plant species (invaders hereafter) and natives receive similar or even the same environmental selection pressures. Thus, the differences in functional traits between natives and invaders have become widely recognized as a major driving force of the success of plant invasion. Meanwhile, increasing amounts of acid are deposited into ecosystems. Thus, it is important to elucidate the potential effects of acid deposition on the functional traits of invaders in order to better understand the potential mechanisms for the successful invasion. This study aims to address the differences in functional traits between native red amaranth (Amaranthus tricolor L.; amaranth hereafter) and invasive redroot pigweed (A. retroflexus L.; pigweed hereafter) under simulated acid deposition with a gradient of pH levels. Pigweed was significantly taller than amaranth under most treatments. The greater height of pigweed can lead to greater competitive ability for resource acquisition, particularly for sunlight. Leaf shape index of pigweed was also significantly greater than that of amaranth under all treatments. The greater leaf shape index of pigweed can enhance the efficiency of resource capture (especially sunlight capture) via adjustments to leaf shape and size. Thus, the greater height and leaf shape index of pigweed can significantly enhance its competitive ability, especially under acid deposition. Acid deposition of pH 5.6 significantly increased amaranth leaf width in the co-cultivation due to added nutrients. The pH 4.5 acid deposition treatment significantly increased the specific leaf area of amaranth in the monoculture compared with the pH 5.6 acid deposition treatment and the control. The main mechanism explaining this pattern may be due to acid deposition mediating a hormesis effect on plants, promoting plant growth. The values of the relative competition intensity between amaranth and pigweed for most functional traits were lower than zero under most

Certified reference materials - beech leaves and spruce needles - for the quality control in monitoring damage in forests by acid deposition

Energy Technology Data Exchange (ETDEWEB)

Maier, E A; Griepink, B [Commission of the European Communities, Brussels (Belgium). Community Bureau of Reference; Muntau, H [Commission of the European Communities, Ispra (Italy). Joint Research Centre

1989-12-01

The chemical determination of various elements in leaves or needles allows to establish the damage caused by acid deposition. To control the quality of such determinations the Community Bureau of Reference (BCR) produced two Certified Reference Materials: Beech leaves (CRM No. 100) and Spruce needles (CRM No. 101). After a careful preparation procedure, a homogeneity study and a long term stability study, the materials were certified for: Cl, N, P and S in CRM No. 100, Al, Ca, Cl, Mg, Mn, N, P, S and Zn in CRM No. 101. Indicative values on the content of 19 majors and trace elements are also reported. (orig.).

U(VI) speciation and reduction in acid chloride fluids in hydrothermal conditions: from transport to deposition of uranium in unconformity-related deposits

International Nuclear Information System (INIS)

Dargent, Maxime

2014-01-01

Circulations of acidic chloride brines in the earth's crust are associated with several types of uranium deposits, particularly unconformity-related uranium (URU) deposits. The spectacular high grade combined with the large tonnage of these deposits is at the origin of the key questions concerning the geological processes responsible for U transport and precipitation. The aim of this work is to performed experimental studies of U(VI) speciation and its reduction to U(IV) subsequently precipitation to uraninite under hydrothermal condition. About uranium transport, the study of U(VI) speciation in acidic brines at high temperature is performed by Raman and XAS spectroscopy, showing the coexistence of several uranyl chloride complexes UO 2 Cl n 2-n (n = 0 - 5). From this study, complexation constants are proposed. The strong capability of chloride to complex uranyl is at the origin of the transport of U(VI) at high concentration in acidic chloride brines. Concerning uranium precipitation, the reactivity of four potential reductants under conditions relevant for URU deposits genesis is investigated: H 2 , CH 4 , Fe(II) and the C-graphite. The kinetics of reduction reaction is measured as a function of temperature, salinity, pH and concentration of reductant. H 2 , CH 4 , and the C-graphite are very efficient while Fe(II) is not able to reduce U(VI) in same conditions. The duration of the mineralizing event is controlled by (i) the U concentration in the ore-forming fluids and (ii) by the generation of gaseous reductants, and not by the reduction kinetics. These mobile and efficient gaseous reductant could be at the origin of the extremely focus and massive character of ore in URU deposits. Finally, first partition coefficients uraninite/fluid of trace elements are obtained. This last part opens-up new perspectives on (i) REE signatures interpretation for a given type of uranium deposit (ii) and reconstruction of mineralizing fluids composition. (author) [fr

Acidic deposition: State of science and technology. Report 14. Methods for projecting future changes in surface water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Thornton, K.W.; Marmorek, D.; Ryan, P.F.; Heltcher, K.; Robinson, D.

1990-09-01

The objectives of the report are to: critically evaluate methods for projecting future effects of acidic deposition on surface water acid-base chemistry; review and evaluate techniques and procedures for analyzing projection uncertainty; review procedures for estimating regional lake and stream population attributes; review the U.S. Environmental Protection Agency (EPA) Direct/Delayed Response Project (DDRP) methodology for projecting the effects of acidic deposition on future changes in surface water acid-base chemistry; and present the models, uncertainty estimators, population estimators, and proposed approach selected to project the effects of acidic deposition on future changes in surface water acid-base chemistry in the NAPAP 1990 Integrated Assessment and discuss the selection rationale

Acid deposition and assessment of its critical load for the environmental health of waterbodies in a subtropical watershed, China

Science.gov (United States)

Jia, Junjie; Gao, Yang

2017-12-01

Atmospheric acidic deposition in subtropical watersheds poses an environmental risk of causing acidification of aquatic ecosystems. In this study, we evaluated the frequency of acid deposition in a subtropical forest ecosystem and the associated critical loads of acidity for a sensitive aquatic ecosystem. We found that out of 132 rainfall events, 33(25%) were acidic rainfall occurrences. Estimated wet acid deposition (2282.78 eq·ha-1·yr-1), consistent with SO42- and NH4+ deposition, was high in spring and summer and low in autumn and winter. Waterbodies surrounded by mixed wood and citrus orchard experience severe acidification, mostly from S deposition because acidic deposition exceeds the corresponding critical loads of acidity. Modifications that take acid rain deposition into consideration are needed for land-use and agricultural management strategies to improve the environmental health of waterbodies in subtropical watersheds.

Absorption characteristics of Kupravas deposit clays modified by phosphoric acid

International Nuclear Information System (INIS)

Ruplis, A.; Mezinskis, G.; Chaghuri, M.

1998-01-01

Literature data suggested that clays may be used as sorbents for waste water treatment. The surface and sorption properties of minerals changes due to the influence of acid rains. The process of recession of clay properties has been modeled in laboratory by treatment of clays with mineral acids at higher temperature that in natural conditions. The present paper is devoted to the study of influence of phosphoric acid on the sorption properties of Kupravas deposit clays. Natural clay samples and samples treated with phosphoric acid were characterized by means of x-ray diffraction an differential thermal analysis (DTA) methods These methods were used also to identify the sample of Lebanese clays. X-ray diffraction analysis data show that the samples of clays from the deposit of Kuprava contain illite and kaolinite while sample of Lebanese clay contains quartz, calcite, and montmorillonite. DTA results show characteristic features of Kuprava clays described in reference with DTA of Lebanese clay clearly demonstrate the presence of large quantity of calcite

Radionuclide deposition control

International Nuclear Information System (INIS)

1980-01-01

A method is described for controlling the deposition, on to the surfaces of reactor components, of the radionuclides manganese-54, cobalt-58 and cobalt-60 from a liquid stream containing the radionuclides. The method consists of disposing a getter material (nickel) in the liquid stream, and a non-getter material (tantalum, tungsten or molybdenum) as a coating on the surfaces where deposition is not desired. The process is described with special reference to its use in the coolant circuit in sodium cooled fast breeder reactors. (U.K.)

Acid atmospheric deposition in a forested mountain catchment

Czech Academy of Sciences Publication Activity Database

Křeček, J.; Palán, L.; Stuchlík, Evžen

2017-01-01

Roč. 10, č. 4 (2017), s. 680-686 ISSN 1971-7458 Institutional support: RVO:60077344 Keywords : mountain water shed * spruce forests * acid atmospheric deposition * water resources recharge Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 1.623, year: 2016

The response of soil solution chemistry in European forests to decreasing acid deposition.

Science.gov (United States)

Johnson, James; Graf Pannatier, Elisabeth; Carnicelli, Stefano; Cecchini, Guia; Clarke, Nicholas; Cools, Nathalie; Hansen, Karin; Meesenburg, Henning; Nieminen, Tiina M; Pihl-Karlsson, Gunilla; Titeux, Hugues; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Waldner, Peter; Jonard, Mathieu

2018-03-31

Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosystems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al tot ) and dissolved organic carbon were determined for the period 1995-2012. Plots with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10-20 cm, 104 plots) and subsoil (40-80 cm, 162 plots). There was a large decrease in the concentration of sulphate (SO42-) in soil solution; over a 10-year period (2000-2010), SO42- decreased by 52% at 10-20 cm and 40% at 40-80 cm. Nitrate was unchanged at 10-20 cm but decreased at 40-80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca 2+  + Mg 2+  + K + ) and Al tot over the entire dataset. The response of soil solution acidity was nonuniform. At 10-20 cm, ANC increased in acid-sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40-80 cm, ANC remained unchanged in acid-sensitive soils (base saturation ≤20%, pHCaCl2 ≤ 4.5) and decreased in better-buffered soils (base saturation >20%, pHCaCl2 > 4.5). In addition, the molar ratio of Bc to Al tot either did not change or decreased. The results suggest a long-time lag between emission abatement and changes in soil solution acidity and underline the importance of long-term monitoring in evaluating ecosystem response to decreases in deposition. © 2018 John Wiley & Sons

Urban acid deposition. Results from the GMADS network, 1990

Energy Technology Data Exchange (ETDEWEB)

Conlan, D.E.; Longhurst, J.W.S.; Gee, D.R.; Hare, S.E.

1991-07-01

This fourth annual data report of the Greater Manchester Acid Deposition Survey (GMADS) gives results from the urban precipitation chemistry network across Greater Manchester and Warrington for 1990. Full analytical methods are described along with precision and accuracy of the methods used. The spatial variability of precipitation chemistry and deposition over this urban region was investigated using a network of twenty collectors. Concentrations of non marine sulphate, ammonium, calcium and hydrogen, and nitrogen dioxide gas concentrations all show significant spatial variability. The spatial variability of the deposition rates of non marine sulphate, nitrate, ammonium, hydrogen and calcium were significant. 40 refs., 13 figs., 9 tabs., 1 app.

Acidic deposition: State of science and technology. Report 10. Watershed and lake processes affecting surface-water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Turner, R.S.; Cook, R.B.; Miegroet, H.V.; Johnson, D.W.; Elwood, J.W.

1990-09-01

The acid-base chemistry of surface waters is governed by the amount and chemistry of deposition and by the biogeochemical reactions that generate acidity or acid neutralizing capacity (ANC) along the hydrologic pathways that water follows through watersheds to streams and lakes. The amount of precipitation and it chemical loading depend on the area's climate and physiography, on it proximity to natural or industrial gaseous or particulate sources, and on local or regional air movements. Vegetation interacts with the atmosphere to enhance both wet and dry deposition of chemicals to a greater or lesser extent, depending on vegetation type. Vegetation naturally acidifies the environment in humid regions through processes of excess base cation uptake and generation of organic acids associated with many biological processes. Natural acid production and atmospheric deposition of acidic materials drive the acidification process. The lake or stream NAC represents a balance between the acidity-and ANC-generating processes that occur along different flow paths in the watershed and the relative importance of each flow path

Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

KAUST Repository

Kravitz, Ben

2009-07-28

We used a general circulation model of Earth\\'s climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m−2 a−1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m−2 a−1 is enough to negatively impact most ecosystems.

Sulfuric acid deposition from stratospheric geoengineering with sulfate aerosols

KAUST Repository

Kravitz, Ben; Robock, Alan; Oman, Luke; Stenchikov, Georgiy L.; Marquardt, Allison B.

2009-01-01

We used a general circulation model of Earth's climate to conduct geoengineering experiments involving stratospheric injection of sulfur dioxide and analyzed the resulting deposition of sulfate. When sulfur dioxide is injected into the tropical or Arctic stratosphere, the main additional surface deposition of sulfate occurs in midlatitude bands, because of strong cross-tropopause flux in the jet stream regions. We used critical load studies to determine the effects of this increase in sulfate deposition on terrestrial ecosystems by assuming the upper limit of hydration of all sulfate aerosols into sulfuric acid. For annual injection of 5 Tg of SO2 into the tropical stratosphere or 3 Tg of SO2 into the Arctic stratosphere, neither the maximum point value of sulfate deposition of approximately 1.5 mEq m−2 a−1 nor the largest additional deposition that would result from geoengineering of approximately 0.05 mEq m−2 a−1 is enough to negatively impact most ecosystems.

Factors affecting the long-term response of surface waters to acidic deposition: state-of-the-science

Energy Technology Data Exchange (ETDEWEB)

Turner, R.S.; Johnson, D.W.; Elwood, J.N.; Van Winkle, W.; Clapp, R.B.; Jones, M.L.; Marmarek, D.R.; Thornton, K.W.; Gherinig, S.A.; Schnoor, J.L.

1986-01-01

Recent intensive study of the causes of surface water acidification has led to numerous hypothesized controlling mechanisms. Among these are the salt-effect reduction of alkalinity, the base cation buffering and sulfate adsorption capacities of soils, availability of weatherable minerals (weathering rates), depth of till, micropore flow, and type of forest cover. Correlative and predictive models have been developed to show the relationships (if any) between hypothesized controlling mechanisms and surface water acidity, and to suggest under what conditions additional surface water might become acid. This document (Part A) is a review of our current knowledge of factors and processes controlling soil and surface water acidification, as well as an assessment of the adequacy of that knowledge for making predictions of future acidification. Section 2 is a data extensive, conceptual overview of how watersheds function. Section 3 is a closer look at the theory and evidence for the key hypotheses. Section 4 is a review of existing methods of assessing system response to acidic deposition.

Deposition of LDH on plasma treated polylactic acid to reduce water permeability

KAUST Repository

Bugatti, Valeria

2013-04-01

A simple and scalable deposition process was developed to prepare polylactic acid (PLA) coatings with enhanced water barrier properties for food packaging applications. This method based on electrostatic interactions between the positively charged layers of layered double hydroxides (LDHs) modified with ionic liquids (ILs) and the negatively charged plasma treated polylactic acid leads to homogeneous, stable, and highly durable coatings. Deposition of the LDH coatings increases the surface hydrophobicity of the neat PLA, which results to a decrease in water permeability by about 35%. © 2013 Elsevier Inc.

Acidic deposition: State of science and technology. Report 9. Current status of surface-water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Baker, L.A.; Kaufmann, P.R.; Brakke, D.F.; Herlihy, A.T.; Eilers, J.M.

1990-09-01

The report is based largely upon the National Surface Water Survey (NSWS), augmented by numerous smaller state and university surveys and many detailed watershed studies. In describing the current status of surface waters, the authors go far beyond the description of population statistics, although some of this is necessary, and direct their attention to the interpretation of these data. They address the question of the sources of acidity to surface waters in order to determine the relative importance of acidic deposition compared with other sources, such as naturally produced organic acids and acid mine drainage. They also examine in some detail what they call 'high interest' populations-the specific groups of lakes and streams most likely to be impacted by acidic deposition. The authors then turn to the general question of uncertainty, and finally examine low alkalinity surface waters in several other parts of the world to develop further inferences about the acid-base status of surface waters in the United States

Influence of containing of asphaltenes and naphthenic acids over organic deposition inhibitor performance

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Geiza E.; Mansur, Claudia R.E.; Pires, Renata V.; Passos, Leonardo B.; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas; Alvares, Dellyo R.S.; Gonzalez, Gaspar [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

2004-07-01

Organic deposition is a serious problem confronted by the petroleum industry in Brazil and worldwide. Among the main petroleum components that may cause deposition problems are waxes and asphaltenes. This work aims at evaluating the influence of petroleum fractions (asphaltenes and naphthenic acids) on the organic deposition phenomenon as well as on organic deposition inhibitors performance. The influence of the organic fractions was evaluated by their ability to change wax crystals, to lower the pour point and to alter the initial wax appearance temperature. The efficiency of the additives was tested by pour point measurements. The results show that asphaltenes seem to act as organic deposition inhibitors, while naphthenic acids do not significantly change the system. Moreover, employing both of them produces no synergic effect. Among polymeric inhibitors, all of the chemically modified EVA copolymer presented better results than the non-modified commercial EVA copolymer. The best result was observed for EVA28C{sub 16}. (author)

Hexanoic Acid Treatment Prevents Systemic MNSV Movement in Cucumis melo Plants by Priming Callose Deposition Correlating SA and OPDA Accumulation

Directory of Open Access Journals (Sweden)

Emma Fernández-Crespo

2017-10-01

Full Text Available Unlike fungal and bacterial diseases, no direct method is available to control viral diseases. The use of resistance-inducing compounds can be an alternative strategy for plant viruses. Here we studied the basal response of melon to Melon necrotic spot virus (MNSV and demonstrated the efficacy of hexanoic acid (Hx priming, which prevents the virus from systemically spreading. We analysed callose deposition and the hormonal profile and gene expression at the whole plant level. This allowed us to determine hormonal homeostasis in the melon roots, cotyledons, hypocotyls, stems and leaves involved in basal and hexanoic acid-induced resistance (Hx-IR to MNSV. Our data indicate important roles of salicylic acid (SA, 12-oxo-phytodienoic acid (OPDA, jasmonic-isoleucine, and ferulic acid in both responses to MNSV. The hormonal and metabolites balance, depending on the time and location associated with basal and Hx-IR, demonstrated the reprogramming of plant metabolism in MNSV-inoculated plants. The treatment with both SA and OPDA prior to virus infection significantly reduced MNSV systemic movement by inducing callose deposition. This demonstrates their relevance in Hx-IR against MNSV and a high correlation with callose deposition. Our data also provide valuable evidence to unravel priming mechanisms by natural compounds.

Measurements of dry-deposition parameters for the California acid-deposition monitoring program. Final report

International Nuclear Information System (INIS)

Watson, J.G.; Chow, J.C.; Egami, R.T.; Bowen, J.L.; Frazier, C.A.

1991-06-01

The State of California monitors the concentrations of acidic gases and particles at 10 sites throughout the state. Seven sites represent urban areas (South Coast Air Basin - three sites, San Francisco Bay Area, Bakersfield, Santa Barbara, and Sacramento) and three represent forested areas (Sequoia National Park, Yosemite National Park, and Gasquet). Several sites are collocated with monitoring instruments for other air quality and forest response networks. Continuous monitors for the dry deposition network collect hourly average values for ozone, wind speed, wind direction, atmospheric stability, temperature, dew point, time of wetness, and solar radiation. A newly-designed gas/particle sampler collects daytime (6 a.m. to 6 p.m.) and nighttime (6 p.m. to 6 a.m.) samples every sixth day for sulfur dioxide, ammonia, nitrogen dioxide, and nitric acid. Particles are collected on the same day/night schedule in PM(10) and PM(2.5) size ranges, and are analyzed for mass, sulfate, nitrate, chloride, ammonium, sodium, magnesium, potassium, and calcium ions. The sampling schedule follows the regulatory schedule adopted by the EPA and ARB for suspended particulate matter. Wet deposition data are collected at or nearby the dry deposition stations. The first year of the monitoring program included installation of the network, training of technicians, acquisition and validation of data, and transfer of the sampling and analysis technology to Air Resources Board operating divisions. Data have been validated and stored for the period May, 1988 through September, 1989

The impact of nitrogen deposition on acid grasslands in the Atlantic region of Europe

Energy Technology Data Exchange (ETDEWEB)

Stevens, Carly J., E-mail: c.j.stevens@open.ac.uk [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom); Dupre, Cecilia [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Dorland, Edu [Ecology and Biodiversity Group, Department of Biology, Institute of Environmental Biology, Utrecht University, PO Box 80.058, 3508 TB Utrecht (Netherlands); Gaudnik, Cassandre [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Gowing, David J.G. [Department of Life Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Bleeker, Albert [Department of Air Quality and Climate Change, Energy Research Centre of the Netherlands, PO Box 1, 1755 ZG Petten (Netherlands); Diekmann, Martin [Institute of Ecology, FB 2, University of Bremen, Leobener Str., DE-28359 Bremen (Germany); Alard, Didier [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Bobbink, Roland [B-WARE Research Centre, Radboud University, PO Box 9010, 6525 ED Nijmegen (Netherlands); Fowler, David [NERC Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB (United Kingdom); Corcket, Emmanuel [University of Bordeaux 1, UMR INRA 1202 Biodiversity, Genes and Communities, Equipe Ecologie des Communautes, Batiment B8 - Avenue des Facultes, F-33405 Talence (France); Mountford, J. Owen [NERC Centre for Ecology and Hydrology, MacLean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB (United Kingdom); Vandvik, Vigdis [Department of Biology, University of Bergen, Box 7800, N-5020 Bergen (Norway)

2011-10-15

A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2-44 kg N ha{sup -1} yr{sup -1}) grass richness as a proportion of total species richness increased whereas forb richness decreased. Soil C:N ratio increased, but soil extractable nitrate and ammonium concentrations did not show any relationship with nitrogen deposition. The above-ground tissue nitrogen contents of three plant species were examined: Agrostis capillaris (grass), Galium saxatile (forb) and Rhytidiadelphus squarrosus (bryophyte). The tissue nitrogen content of neither vascular plant species showed any relationship with nitrogen deposition, but there was a weak positive relationship between R. squarrosus nitrogen content and nitrogen deposition. None of the species showed strong relationships between above-ground tissue N:P or C:N and nitrogen deposition, indicating that they are not good indicators of deposition rate. - Highlights: > N deposition is negatively correlated with forb richness as a proportion of species richness. > Soil C:N ratio increased with increasing N deposition. > Soil extractable nitrate and ammonium were not related to nitrogen deposition. > Plant-tissue N content was not a good indicator of N deposition. - Atmospheric nitrogen deposition affects soils, plant-tissue chemistry and plant species composition in acid grasslands in the Atlantic biogeographic region of Europe.

The impact of nitrogen deposition on acid grasslands in the Atlantic region of Europe

International Nuclear Information System (INIS)

Stevens, Carly J.; Dupre, Cecilia; Dorland, Edu; Gaudnik, Cassandre; Gowing, David J.G.; Bleeker, Albert; Diekmann, Martin; Alard, Didier; Bobbink, Roland; Fowler, David; Corcket, Emmanuel; Mountford, J. Owen; Vandvik, Vigdis

2011-01-01

A survey of 153 acid grasslands from the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is changing plant species composition and soil and plant-tissue chemistry. Across the deposition gradient (2-44 kg N ha -1 yr -1 ) grass richness as a proportion of total species richness increased whereas forb richness decreased. Soil C:N ratio increased, but soil extractable nitrate and ammonium concentrations did not show any relationship with nitrogen deposition. The above-ground tissue nitrogen contents of three plant species were examined: Agrostis capillaris (grass), Galium saxatile (forb) and Rhytidiadelphus squarrosus (bryophyte). The tissue nitrogen content of neither vascular plant species showed any relationship with nitrogen deposition, but there was a weak positive relationship between R. squarrosus nitrogen content and nitrogen deposition. None of the species showed strong relationships between above-ground tissue N:P or C:N and nitrogen deposition, indicating that they are not good indicators of deposition rate. - Highlights: → N deposition is negatively correlated with forb richness as a proportion of species richness. → Soil C:N ratio increased with increasing N deposition. → Soil extractable nitrate and ammonium were not related to nitrogen deposition. → Plant-tissue N content was not a good indicator of N deposition. - Atmospheric nitrogen deposition affects soils, plant-tissue chemistry and plant species composition in acid grasslands in the Atlantic biogeographic region of Europe.

Impact of acid atmosphere deposition on soils : field monitoring and aluminum chemistry

NARCIS (Netherlands)

Mulder, J.

1988-01-01

The effect of acid atmospheric deposition on concentrations and transfer of major solutes in acid, sandy soils was studied. Emphasis was given to mobilization and transport of potentially toxic aluminum. Data on solute concentrations and fluxes in meteoric water as well as soil solutions

Acid-deposition research program. Volume 2. Effects of acid-forming emissions on soil microorganisms and microbially-mediated processes

Energy Technology Data Exchange (ETDEWEB)

Visser, S.; Danielson, R.M.; Parr, J.F.

1987-02-01

The interactions of soil physical, chemical, and biological processes are ultimately expressed in a soil's fertility and its capacity for plant production. Consequently, much of the research conducted to date regarding the impact of acid-forming pollutants on soil properties has been geared towards possible effects on plant productivity. This trend continues in this paper where the effects of acidic deposition on microbial communities are reviewed in relation to potential impact on plant growth. The objectives of the review are to discuss: (1) The effects of acid-forming emissions (primarily S-containing pollutants) on microbial community structure with emphasis on qualitative and quantitative aspects; (2) The effects of acidic deposition on microbially mediated processes (i.e., community functions); (3) Acidification effects of pollutants on symbiotic and disease-causing microorganisms. The symbionts discussed include ectomycorrhizal fungi, vesicular-arbuscular mycorrhizal fungi, and N/sub 2/-fixing bacteria, particularly Rhizobium, while the disease-causing microorganisms will include those responsible for foliage, stem, and root diseases.

Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

Science.gov (United States)

Sullivan, Timothy J.; Lawrence, Gregory B.; Bailey, Scott W.; McDonnell, Todd C.; McPherson, G.T.

2013-01-01

This study documents the effects of acidic deposition and soil acid-base chemistry on the growth, regeneration, and canopy condition of sugar maple (SM) trees in the Adirondack Mountains of New York. Sugar maple is the dominant canopy species throughout much of the northern hardwood forest in the State. A field study was conducted in 2009 in which 50 study plots within 20 small Adirondack watersheds were sampled and evaluated for soil acid-base chemistry and SM growth, canopy condition, and regeneration. Atmospheric sulfur (S) and nitrogen (N) deposition were estimated for each plot. Trees growing on soils with poor acid-base chemistry (low exchangeable calcium and % base saturation) that receive relatively high levels of atmospheric S and N deposition exhibited little to no SM seedling regeneration, decreased canopy condition, and short-to long-term growth declines compared with study plots having better soil condition and lower levels of atmospheric deposition. These results suggest that the ecosystem services provided by SM in the western and central Adirondack Mountain region, including aesthetic, cultural, and monetary values, are at risk from ongoing soil acidification caused in large part by acidic deposition.

Deposit control in process cooling water systems

International Nuclear Information System (INIS)

Venkataramani, B.

1981-01-01

In order to achieve efficient heat transfer in cooling water systems, it is essential to control the fouling of heat exchanger surfaces. Solubilities of scale forming salts, their growth into crystals, and the nature of the surfaces play important roles in the deposition phenomenon. Condensed phosphates, organic polymers and compounds like phosphates are effective in controlling deposition of scale forming salts. The surface active agents inhibit crystal growth and modify the crystals of the scale forming salts, and thus prevent deposition of dense, uniformly structured crystalline mass on the heat transfer surface. Understanding the mechanism of biofouling is essential to control it by surface active agents. Certain measures taken in the plant, such as back flushing, to control scaling, sometimes may not be effective and can be detrimental to the system itself. (author)

Catchment hydrochemical processes controlling acidity and nitrogen in forest stream water

International Nuclear Information System (INIS)

Foelster, Jens

2001-01-01

Atmospheric deposition of air pollutants has been a severe threat to terrestrial and forest ecosystems for several decades. In Sweden sulphur deposition has caused acidification of soils and runoff, while nitrogen deposition only had a minor or local impact on runoff quality so far. During the last three decades, emission control has caused a decline in sulphur deposition, whereas nitrogen deposition on the other hand, has continued to increase to a rate several times above the natural background level. Long term changes in runoff acidity and nitrogen chemistry after these changes in deposition are of great concern. Monitoring of small, well-defined catchments including hydrochemistry of precipitation, soil and runoff, is a valuable tool for addressing this concern. When interpreting runoff data from such sites, the near-stream zone has been identified to be of crucial importance. The main objective for this thesis was to explain how catchment processes were related to short-term variation and long-term trends in the hydrochemistry of forest stream water. The field work was conducted on the strongly acidified and nitrogen limited Kindla catchment, with a special emphasis on the relationship between the near-stream zone and both stream acidity and nitrogen leaching. Furthermore, time series of hydrochemistry in forest stream water from 13 catchments were analysed for changes in acidity and nitrogen leaching. In three of these sites, soil water from E- and B-horizons was also analysed with regards to these questions. The investigations revealed that the near-stream zone was a net source of acidity in runoff at Kindla due to leaching of organic acids, although this contribution was overshadowed by sulphate from upland soils and deposition. The near-stream zone was also the main source for both organic nitrogen and nitrate to the stream, but the leaching rate was low, especially for inorganic nitrogen. In the 13 reference streams, sulphate concentrations declined in

Poly(aniline-co-m-aminobenzoic acid) deposited on poly(vinyl ...

Indian Academy of Sciences (India)

Abstract. In this work, we have deposited poly(aniline-co-m-aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ ... along the polyaniline (PANI) chain results in self dop- ing of PANI and ..... The value of electrical conductivity is found to be ...

Zinc deposition and dissolution in methanesulfonic acid onto a carbon composite electrode as the negative electrode reactions in a hybrid redox flow battery

International Nuclear Information System (INIS)

Leung, P.K.; Ponce-de-Leon, C.; Low, C.T.J.; Walsh, F.C.

2011-01-01

Highlights: → Use methanesulfonic acid to avoid dendrite formation during a long (>4 h) zinc electrodeposition. → Electrochemical characterization of Zn(II) deposition and its morphology using methanesulfonic acid solutions. → Use of additives to improve the efficiency of zinc deposition and dissolution as the half cell reaction of a redox flow battery. - Abstract: Electrodeposition and dissolution of zinc in methanesulfonic acid were studied as the negative electrode reactions in a hybrid redox flow battery. Cyclic voltammetry at a rotating disk electrode was used to characterize the electrochemistry and the effect of process conditions on the deposition and dissolution rate of zinc in aqueous methanesulfonic acid. At a sufficiently high current density, the deposition process became a mass transport controlled reaction. The diffusion coefficient of Zn 2+ ions was 7.5 x 10 -6 cm 2 s -1 . The performance of the zinc negative electrode in a parallel plate flow cell was also studied as a function of Zn 2+ ion concentration, methanesulfonic acid concentration, current density, electrolyte flow rate, operating temperature and the addition of electrolytic additives, including potassium sodium tartarate, tetrabutylammonium hydroxide, and indium oxide. The current-, voltage- and energy efficiencies of the zinc-half cell reaction and the morphologies of the zinc deposits are also discussed. The energy efficiency improved from 62% in the absence of additives to 73% upon the addition of 2 x 10 -3 mol dm -3 of indium oxide as a hydrogen suppressant. In aqueous methanesulfonic acid with or without additives, there was no significant dendrite formation after zinc electrodeposition for 4 h at 50 mA cm -2 .

Effect of humic acid on the underpotential deposition-stripping voltammetry of copper in acetic acid soil extract solutions at mercaptoacetic acid-modified gold electrodes

Energy Technology Data Exchange (ETDEWEB)

Herzog, Gregoire; Beni, Valerio; Dillon, Patrick H.; Barry, Thomas; Arrigan, Damien W.M

2004-05-24

Electrochemical measurements were undertaken for the investigation of the underpotential deposition-stripping process of copper at bare and modified gold electrodes in 0.11 M acetic acid, the first fraction of the European Union's Bureau Communautaire de References (BCR) sequential extraction procedure for fractionating metals within soils and sediments. Gold electrodes modified with mercaptoacetic acid showed higher sensitivity for the detection of copper than bare gold electrodes, both in the absence and in the presence of humic acid in acetic acid solutions, using the underpotential deposition-stripping voltammetry (UPD-SV) method. In the presence of 50 mg l{sup -1} of humic acid, the mercaptoacetic acid modified electrode proved to be 1.5 times more sensitive than the bare gold electrode. The mercaptoacetic acid monolayer formed on the gold surface provided efficient protection against the adsorption of humic acid onto the gold electrode surface. Variation of the humic acid concentration in the solution showed little effect on the copper stripping signal at the modified electrode. UPD-SV at the modified electrode was applied to the analysis of soil extract samples. Linear correlation of the electrochemical results with atomic spectroscopic results yielded the straight-line equation y ({mu}g l{sup -1}) = 1.10x - 44 (ppb) (R=0.992, n=6), indicating good agreement between the two methods.

Influence of Humic Acid on the Transport and Deposition of Colloidal Silica under Different Hydrogeochemical Conditions

Directory of Open Access Journals (Sweden)

Jingjing Zhou

2016-12-01

Full Text Available The transport and deposition of colloids in aquifers plays an important role in managed aquifer recharge (MAR schemes. Here, the processes of colloidal silica transport and deposition were studied by displacing groundwater with recharge water. The results showed that significant amounts of colloidal silica transport occurred when native groundwater was displaced by HA solution. Solution contains varying conditions of ionic strength and ion valence. The presence of humic acid could affect the zeta potential and size of the colloidal silica, which led to obvious colloidal silica aggregation in the divalent ion solution. Humic acid increased colloidal silica transport by formation of non-adsorbing aqueous phase silica–HA complexes. The experimental and modeling results showed good agreement, indicating that the essential physics were accurately captured by the model. The deposition rates were less than 10−8 s−1 in deionized water and monovalent ion solution. Moreover, the addition of Ca2+ and increase of IS resulted in the deposition rates increasing by five orders of magnitude to 10−4 s−1. In all experiments, the deposition rates decreased in the presence of humic acid. Overall, the promotion of humic acid in colloidal silica was strongly associated with changes in water quality, indicating that they should receive greater attention during MAR.

A decade of monitoring at Swiss Long-Term Forest Ecosystem Research (LWF) sites: can we observe trends in atmospheric acid deposition and in soil solution acidity?

Science.gov (United States)

Pannatier, Elisabeth Graf; Thimonier, Anne; Schmitt, Maria; Walthert, Lorenz; Waldner, Peter

2011-03-01

Trends in atmospheric acid deposition and in soil solution acidity from 1995 or later until 2007 were investigated at several forest sites throughout Switzerland to assess the effects of air pollution abatements on deposition and the response of the soil solution chemistry. Deposition of the major elements was estimated from throughfall and bulk deposition measurements at nine sites of the Swiss Long-Term Forest Ecosystem Research network (LWF) since 1995 or later. Soil solution was measured at seven plots at four soil depths since 1998 or later. Trends in the molar ratio of base cations to aluminum (BC/Al) in soil solutions and in concentrations and fluxes of inorganic N (NO(3)-N + NH(4)-N), sulfate (SO(4)-S), and base cations (BC) were used to detect changes in soil solution chemistry. Acid deposition significantly decreased at three out of the nine study sites due to a decrease in total N deposition. Total SO(4)-S deposition decreased at the nine sites, but due to the relatively low amount of SO(4)-S load compared to N deposition, it did not contribute to decrease acid deposition significantly. No trend in total BC deposition was detected. In the soil solution, no trend in concentrations and fluxes of BC, SO(4)-S, and inorganic N were found at most soil depths at five out of the seven sites. This suggests that the soil solution reacted very little to the changes in atmospheric deposition. A stronger reduction in base cations compared to aluminum was detected at two sites, which might indicate that acidification of the soil solution was proceeding faster at these sites.

Effects of acidic deposition on the erosion of carbonate stone - experimental results from the U. S. National Acid Precipitation Assessment Program (NAPAP)

Energy Technology Data Exchange (ETDEWEB)

Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A. (US Geological Survey, Reston, VA (USA))

1992-06-01

Test briquettes and slabs of freshly quarried limestone and marble have been exposed to the environment to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulphur dioxide, and nitrogen oxides on stone erosion. Erosion due to grain loss did not seem to be influenced by rainfall acidity, but may be influenced by dry deposition of sulphur dioxide between rainfall events. Chemical analyses of the run-off solutions suggest that around 30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulphur dioxide and nitric acid between rain events. The remaining 70% of erosion by dissolution is accounted for by the solubility of carbonate stone in 'clean' rain. 17 refs., 4 figs., 7 tabs.

The Tracking and Analysis Framework (TAF): A tool for the integrated assessment of acid deposition

International Nuclear Information System (INIS)

Bloyd, C.N.; Henrion, M.; Marnicio, R.J.

1995-01-01

A major challenge that has faced policy makers concerned with acid deposition is obtaining an integrated view of the underlying science related to acid deposition. In response to this challenge, the US Department of Energy is sponsoring the development of an integrated Tracking and Analysis Framework (TAF) which links together the key acid deposition components of emissions, air transport, atmospheric deposition, and aquatic effects in a single modeling structure. The goal of TAF is to integrate credible models of the scientific and technical issues into an assessment framework that can directly address key policy issues, and in doing so act as a bridge between science and policy. Key objectives of TAF are to support coordination and communication among scientific researchers; to support communications with policy makers, and to provide rapid response for analyzing newly emerging policy issues; and to provide guidance for prioritizing research programs. This paper briefly describes how TAF was formulated to meet those objectives and the underlying principals which form the basis for its development

Formulation of porous poly(lactic-co-glycolic acid) microparticles by electrospray deposition method for controlled drug release

Energy Technology Data Exchange (ETDEWEB)

Hao, Shilei; Wang, Yazhou; Wang, Bochu, E-mail: wangbc2000@126.com; Deng, Jia; Zhu, Liancai; Cao, Yang

2014-06-01

In the present study, the electrospray deposition was successfully applied to prepare the porous poly(lactic-co-glycolic acid) (PLGA) microparticles by one-step processing. Metronidazole was selected as the model drug. The porous PLGA microparticles had high drug loading and low density, and the porous structure can be observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The production time has been shortened considerably compared with that of the traditional multi-emulsion method. In addition, no chemical reaction occurred between the drug and polymer in the preparation of porous microparticles, and the crystal structure of drug did not change after entrapment into the porous microparticles. The porous microparticles showed a sustained release in the simulated gastric fluid, and the release followed non-Fickian or case II transport. Furthermore, porous microparticles showed a slight cytotoxicity in vitro. The results indicated that electrospray deposition is a good technique for preparation of porous microparticles, and the low-density porous PLGA microparticles has a potential for the development of gastroretentive systems or for pulmonary drug delivery. - Highlights: • The porous PLGA microparticles were successfully prepared by the electrospray deposition method at one step. • The porous microparticles had high loading capacity and low density. • The microparticle showed a sustained release in the simulated gastric liquid. • The microparticles showed a slight cytotoxicity in vitro.

Formulation of porous poly(lactic-co-glycolic acid) microparticles by electrospray deposition method for controlled drug release

International Nuclear Information System (INIS)

Hao, Shilei; Wang, Yazhou; Wang, Bochu; Deng, Jia; Zhu, Liancai; Cao, Yang

2014-01-01

In the present study, the electrospray deposition was successfully applied to prepare the porous poly(lactic-co-glycolic acid) (PLGA) microparticles by one-step processing. Metronidazole was selected as the model drug. The porous PLGA microparticles had high drug loading and low density, and the porous structure can be observed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The production time has been shortened considerably compared with that of the traditional multi-emulsion method. In addition, no chemical reaction occurred between the drug and polymer in the preparation of porous microparticles, and the crystal structure of drug did not change after entrapment into the porous microparticles. The porous microparticles showed a sustained release in the simulated gastric fluid, and the release followed non-Fickian or case II transport. Furthermore, porous microparticles showed a slight cytotoxicity in vitro. The results indicated that electrospray deposition is a good technique for preparation of porous microparticles, and the low-density porous PLGA microparticles has a potential for the development of gastroretentive systems or for pulmonary drug delivery. - Highlights: • The porous PLGA microparticles were successfully prepared by the electrospray deposition method at one step. • The porous microparticles had high loading capacity and low density. • The microparticle showed a sustained release in the simulated gastric liquid. • The microparticles showed a slight cytotoxicity in vitro

The allelopathic effects of invasive plant Solidago canadensis on seed germination and growth of Lactuca sativa enhanced by different types of acid deposition.

Science.gov (United States)

Wang, Congyan; Xiao, Hongguang; Zhao, Lulu; Liu, Jun; Wang, Lei; Zhang, Fei; Shi, Yanchun; Du, Daolin

2016-04-01

Invasive species can exhibit allelopathic effects on native species. Meanwhile, the types of acid deposition are gradually changing. Thus, the allelopathic effects of invasive species on seed germination and growth of native species may be altered or even enhanced under conditions with diversified acid deposition. This study aims to assess the allelopathic effects (using leaves extracts) of invasive plant Solidago canadensis on seed germination and growth of native species Lactuca sativa treated with five types of acid deposition with different SO4(2-) to NO3(-) ratios (1:0, sulfuric acid; 5:1, sulfuric-rich acid; 1:1, mixed acid; 1:5, nitric-rich acid; 0:1, nitric acid). Solidago canadensis leaf extracts exhibited significantly allelopathic effects on germination index, vigor index, and germination rate index of L. sativa. High concentration of S. canadensis leaf extracts also similarly exhibited significantly allelopathic effects on root length of L. sativa. This may be due to that S. canadensis could release allelochemicals and then trigger allelopathic effects on seed germination and growth of L. sativa. Acid deposition exhibited significantly negative effects on seedling biomass, root length, seedling height, germination index, vigor index, and germination rate index of L. sativa. This may be ascribed to the decreased soil pH values mediated by acid deposition which could produce toxic effects on seedling growth. Sulfuric acid deposition triggered more toxic effects on seedling biomass and vigor index of L. sativa than nitric acid deposition. This may be attributing to the difference in exchange capacity with hydroxyl groups (OH(-)) between SO4(2-) and NO3(-) as well as the fertilizing effects mediated by nitric deposition. All types of acid deposition significantly enhanced the allelopathic effects of S. canadensis on root length, germination index, vigor index, and germination rate index of L. sativa. This may be due to the negatively synergistic effects of

Application of a complex transport problem for simulating an acid rain episode in Europe. Anwendung eines komplexen Ausbreitungsmodells zur Simulation einer Episode saurer Deposition ueber Europa

Energy Technology Data Exchange (ETDEWEB)

Stern, R; Scherer, B

1989-04-01

For the first time in Europe, a comprehensive Eulerian regional tropospheric transport, transformation and removal model has been applied to an european wide acid deposition episode. This model, the Transport And Deposition of Acidifying Pollutants (TADAP) model incorporated detailed knowledge of the relevant physicochemical processes which lead to the formation of photochemical oxidants and acidifying pollutants. The EUROPA-model (EUM) of the German Weather Service, a limited area numerical weather prediction model, has been used to derive the total meteorological cloud variables. The application of the EUM/TADAP-modelling system to a 20 day-wintertime acid deposition episode in Europe showed that it is possible to model the principal features of the acid deposition system. In general, there is reasonable agreement between observed and predicted concentration and deposition patterns. Most discrepancies from observed trends can be explained by deviations between the modelled and the actual meteorology. First sensitivity studies with TADAP directed to reveal the influence of emission changes on the acid deposition system showed that there are considerable non-proportionalities between depositions of secondary pollutants and the emissions of the respective precursors. The nonlinearities arise due to the chemical coupling of the SO{sub x}/No{sub x}/VOC-system. This makes the design of control strategies to a highly complex task. Strategies developed to tackle different air pollution problems can therefore not be looked upon independently. (orig.) With 47 refs., 42 figs.

Control of thermal therapies with moving power deposition field

International Nuclear Information System (INIS)

Arora, Dhiraj; Minor, Mark A; Skliar, Mikhail; Roemer, Robert B

2006-01-01

A thermal therapy feedback control approach to control thermal dose using a moving power deposition field is developed and evaluated using simulations. A normal tissue safety objective is incorporated in the controller design by imposing constraints on temperature elevations at selected normal tissue locations. The proposed control technique consists of two stages. The first stage uses a model-based sliding mode controller that dynamically generates an 'ideal' power deposition profile which is generally unrealizable with available heating modalities. Subsequently, in order to approximately realize this spatially distributed idealized power deposition, a constrained quadratic optimizer is implemented to compute intensities and dwell times for a set of pre-selected power deposition fields created by a scanned focused transducer. The dwell times for various power deposition profiles are dynamically generated online as opposed to the commonly employed a priori-decided heating strategies. Dynamic intensity and trajectory generation safeguards the treatment outcome against modelling uncertainties and unknown disturbances. The controller is designed to enforce simultaneous activation of multiple normal tissue temperature constraints by rapidly switching between various power deposition profiles. The hypothesis behind the controller design is that the simultaneous activation of multiple constraints substantially reduces treatment time without compromising normal tissue safety. The controller performance and robustness with respect to parameter uncertainties is evaluated using simulations. The results demonstrate that the proposed controller can successfully deliver the desired thermal dose to the target while maintaining the temperatures at the user-specified normal tissue locations at or below the maximum allowable values. Although demonstrated for the case of a scanned focused ultrasound transducer, the developed approach can be extended to other heating modalities with

Effects of acid and alkaline based surface preparations on spray deposited cerium based conversion coatings on Al 2024-T3

Energy Technology Data Exchange (ETDEWEB)

Pinc, W. [Department of Materials Science Engineering, Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65409 (United States)], E-mail: wrphw5@mst.edu; Geng, S.; O' Keefe, M.; Fahrenholtz, W.; O' Keefe, T. [Department of Materials Science Engineering, Materials Research Center, Missouri University of Science and Technology, Rolla, MO 65409 (United States)

2009-01-15

Cerium based conversion coatings were spray deposited on Al 2024-T3 and characterized to determine the effect of surface preparation on the deposition rate and surface morphology. It was found that activation of the panel using a 1-wt.% sulfuric acid solution increased the coating deposition rate compared to alkaline cleaning alone. Analysis of the surface morphology of the coatings showed that the coatings deposited on the acid treated panels exhibited fewer visible cracks compared to coatings on alkaline cleaned panels. Auger electron spectroscopy depth profiling showed that the acid activation decreased the thickness of the aluminum oxide layer and the concentration of magnesium on the surface of the panels compared to the alkaline treatment. Additionally, acid activation increased the copper concentration at the surface of the aluminum substrate. Based on the results, the acid based surface treatment appeared to expose copper rich intermetallics, thus increasing the number of cathodic sites on the surface, which led to an overall increase in the deposition rate.

Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

International Nuclear Information System (INIS)

Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

2013-01-01

Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate

Electrophoretic deposition and electrochemical behavior of novel graphene oxide-hyaluronic acid-hydroxyapatite nanocomposite coatings

Science.gov (United States)

Li, Ming; Liu, Qian; Jia, Zhaojun; Xu, Xuchen; Shi, Yuying; Cheng, Yan; Zheng, Yufeng; Xi, Tingfei; Wei, Shicheng

2013-11-01

Novel ternary graphene oxide-hyaluronic acid-hydroxyapatite (GO-HY-HA) nanocomposite coatings were prepared on Ti substrate using anodic electrophoretic deposition (EPD). Hyaluronic acid was employed as charging additive and dispersion agent during EPD. The kinetics and mechanism of the deposition, and the microstructure of the coated samples were investigated using scanning electron microscopy, X-ray diffraction, Raman spectrum, thermo-gravimetric analysis, and microscopic Fourier transform infrared analysis. The results showed that the addition of GO sheets into the HY-HA suspensions could increase the deposition rate and inhibit cracks creation and propagation in the coatings. The corrosion resistant of the resulting samples were evaluated using potentiodynamic polarization method in simulated body fluid, and the GO-HY-HA coatings could effectively improve the anti-corrosion property of the Ti substrate.

Deposition of LDH on plasma treated polylactic acid to reduce water permeability

KAUST Repository

Bugatti, Valeria; Livi, Sebastien; Hayrapetyan, Suren; Wang, Yue; Estevez, Luis; Vittoria, Vittoria; Giannelis, Emmanuel P.

2013-01-01

A simple and scalable deposition process was developed to prepare polylactic acid (PLA) coatings with enhanced water barrier properties for food packaging applications. This method based on electrostatic interactions between the positively charged

Controllable deposition of gadolinium doped ceria electrolyte films by magnetic-field-assisted electrostatic spray deposition

International Nuclear Information System (INIS)

Ksapabutr, Bussarin; Chalermkiti, Tanapol; Wongkasemjit, Sujitra; Panapoy, Manop

2013-01-01

This paper describes a simple and low-temperature approach to fabrication of dense and crack-free gadolinium doped ceria (GDC) thin films with controllable deposition by a magnetic-field-assisted electrostatic spray deposition technique. The influences of external permanent magnets on the deposition of GDC films were investigated. The coating area deposited using two magnets with the same pole arrangement decreased in comparison with the case of no magnets, whereas the largest deposition area was obtained in the system of the opposite poles. Analysis of as-deposited films at 450 °C indicated the formation of uniform, smooth and dense thin films with a single-phase fluorite structure. The films produced in the system using same poles were thicker, smaller in crystallite size and smoother than those fabricated under other conditions. Additionally, the GDC film deposited using the same pole arrangement showed the maximum in electrical conductivity of about 2.5 × 10 −2 S/cm at a low operating temperature of 500 °C. - Highlights: • Magnetic-field-assisted electrostatic spray allows a controllable coating. • Dense, crack-free thin films were obtained at low process temperature of 450 °C. • Control of deposition, thickness and uniformity is easy to achieve simultaneously. • Films from the same pole were thicker, smaller in crystal size and smoother. • The maximum conductivity of doped ceria film was 2.5 × 10 −2 S/cm at 500 °C

Effect of Time and Deposition Method on Quality of Phosphonic Acid Modifier Self-Assembled Monolayers on Indium Zinc Oxide

Energy Technology Data Exchange (ETDEWEB)

Sang, Lingzi; Knesting, Kristina M.; Bulusu, Anuradha; Sigdel, Ajaya K.; Giordano, Anthony J.; Marder, Seth R.; Berry, Joseph J.; Graham, Samuel; Ginger, David S.; Pemberton, Jeanne E.

2016-12-15

Phosphonic acid (PA) self-assembled monolayers (SAMs) are utilized at critical interfaces between transparent conductive oxides (TCO) and organic active layers in organic photovoltaic devices (OPVs). The effects of PA deposition method and time on the formation of close-packed, high-quality monolayers is investigated here for SAMs fabricated by solution deposition, micro-contact printing, and spray coating. The solution deposition isotherm for pentafluorinated benzylphosphonic acid (F5BnPA) on indium-doped zinc oxide (IZO) is studied using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) at room temperature as a model PA/IZO system. Fast surface adsorption occurs within the first min; however, well-oriented high-quality SAMs are reached only after -48 h, presumably through a continual process of molecular adsorption/desorption and monolayer filling accompanied by molecular reorientation. Two other rapid, soak-free deposition techniques, micro-contact printing and spray coating, are also explored. SAM quality is compared for deposition of phenyl phosphonic acid (PPA), F13-octylphosphonic acid (F13OPA), and pentafluorinated benzyl phosphonic acid (F5BnPA) by solution deposition, micro-contact printing and spray coating using PM-IRRAS. In contrast to micro-contact printing and spray coating techniques, 48-168 h solution deposition at both room temperature and 70 degrees C result in contamination- and surface etch-free close-packed monolayers with good reproducibility. SAMs fabricated by micro-contact printing and spray coating are much less well ordered.

Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

Energy Technology Data Exchange (ETDEWEB)

Kuperman, R.G. [Argonne National Lab., IL (United States). Environmental Assessment Div.

1996-02-01

Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

Steam generator deposit control program assessment at Comanche Peak

International Nuclear Information System (INIS)

Stevens, J.; Fellers, B.; Orbon, S.

2002-01-01

Comanche Peak has employed a variety of methods to assess the effectiveness of the deposit control program. These include typical methods such as an extensive visual inspection program and detailed corrosion product analysis and trending. In addition, a recently pioneered technique, low frequency eddy current profile analysis (LFEC) has been utilized. LFEC provides a visual mapping of the magnetite deposit profile of the steam generator. Analysis of the LFEC results not only provides general area deposition rates, but can also provide local deposition patterns, which is indicative of steam generator performance. Other techniques utilized include trending of steam pressure, steam generator hideout-return, and flow assisted corrosion (FAC) results. The sum of this information provides a comprehensive assessment of the deposit control program effectiveness and the condition of the steam generator. It also provides important diagnostic and predictive information relative to steam generator life management and mitigative strategies, such as special cleaning procedures. This paper discusses the techniques employed by Comanche Peak Chemistry to monitor the effectiveness of the deposit control program and describes how this information is used in strategic planning. (authors)

Acid rain and nitrogen deposition in a sub-tropical watershed (Piracicaba): ecosystem consequences

International Nuclear Information System (INIS)

Krusche, A.V.; Camargo, P.B. de; Cerri, C.E.; Ballester, M.V.; Lara, L.B.L.S.; Victoria, R.L.; Martinelli, L.A.

2003-01-01

Poorly buffered sandy soils may result in acidification problems for forests in this basin. - High levels of wet N and acidic deposition were measured in southeast Brazil. In this study we addressed the sensitivity of water bodies and soils to acidification and N deposition in the Piracicaba River basin (12,400 km 2 ). Average acid neutralization capacity (ANC) at 23 river sampling sites varied from 350 to 1800 μeq l -1 . Therefore, rivers and streams in the Piracicaba basin are well buffered, if the lower limit of 200 μeq l -1 is assumed as an indication of poorly buffered waters. ANC is increased by untreated wastewaters discarded into rivers and streams of the region. Average NO 3 concentrations varied from 20 to 70 μeq l -1 . At the most polluted river sites, NO 3 concentration is not highest, however, probably due to NO 3 reduction and denitrification. Most of the nitrogen in streams is also provided by wastewaters and not by wet deposition. The majority of the soils in the basin, however, are acidic with a low base cation content and high aluminum concentration. Therefore, soils in this basin are poorly buffered and, in areas of forest over sandy soils, acidification may be a problem

Effect of time and deposition method on quality of phosphonic acid modifier self-assembled monolayers on indium zinc oxide

Energy Technology Data Exchange (ETDEWEB)

Sang, Lingzi [Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721 (United States); Knesting, Kristina M. [Department of Chemistry, University of Washington, Seattle, WA 98195-1700 (United States); Bulusu, Anuradha [School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Sigdel, Ajaya K. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); Giordano, Anthony J.; Marder, Seth R. [School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Berry, Joseph J. [National Renewable Energy Laboratory, Golden, CO 80401 (United States); Graham, Samuel [School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Ginger, David S. [Department of Chemistry, University of Washington, Seattle, WA 98195-1700 (United States); Pemberton, Jeanne E., E-mail: pembertn@email.arizona.edu [Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ 85721 (United States)

2016-12-15

Highlights: • Deposition of phosphonic acid monolayers on oxides from ethanol solutions occurs by rapid adsorption within 10 s with slower equilibration complete in 48 h. • The slower equilibration step involves molecular reorientation and vacancy filling on the oxide surface. • Soak-free deposition by spray coating and microcontact printing do not provide reproducible, fully-covered, uniform monolayers without substrate etching. • Adjustments to exposure time, substrate temperature, and solution/substrate contact efficiency are necessary to optimize soak-free methods. - Abstract: Phosphonic acid (PA) self-assembled monolayers (SAMs) are utilized at critical interfaces between transparent conductive oxides (TCO) and organic active layers in organic photovoltaic devices (OPVs). The effects of PA deposition method and time on the formation of close-packed, high-quality monolayers is investigated here for SAMs fabricated by solution deposition, micro-contact printing, and spray coating. The solution deposition isotherm for pentafluorinated benzylphosphonic acid (F{sub 5}BnPA) on indium-doped zinc oxide (IZO) is studied using polarization modulation-infrared reflection-absorption spectroscopy (PM-IRRAS) at room temperature as a model PA/IZO system. Fast surface adsorption occurs within the first min; however, well-oriented high-quality SAMs are reached only after ∼48 h, presumably through a continual process of molecular adsorption/desorption and monolayer filling accompanied by molecular reorientation. Two other rapid, soak-free deposition techniques, micro-contact printing and spray coating, are also explored. SAM quality is compared for deposition of phenyl phosphonic acid (PPA), F{sub 13}-octylphosphonic acid (F{sub 13}OPA), and pentafluorinated benzyl phosphonic acid (F{sub 5}BnPA) by solution deposition, micro-contact printing and spray coating using PM-IRRAS. In contrast to micro-contact printing and spray coating techniques, 48–168 h solution

Foliar loading and metabolic assimilation of dry deposited nitric acid air pollutants by trees

Science.gov (United States)

Pamela E. Padgett; Hillary Cook; Andrzej Bytnerowicz; Robert L. Heath

2009-01-01

Dry deposition of nitric acid vapor (HNO(3)) is a major contributor to eutrophication of natural ecosystems. Although soil fertilization by nitrogen deposition is considered to be the primary pathway for changes in plant nutrient status and shifts in ecological structure, the aerial portion of plants offer many times the surface area in which to...

Controlling the resistivity gradient in chemical vapor deposition-deposited aluminum-doped zinc oxide

NARCIS (Netherlands)

Ponomarev, M. V.; Verheijen, M. A.; Keuning, W.; M. C. M. van de Sanden,; Creatore, M.

2012-01-01

Aluminum-doped ZnO (ZnO:Al) grown by chemical vapor deposition (CVD) generally exhibit a major drawback, i.e., a gradient in resistivity extending over a large range of film thickness. The present contribution addresses the plasma-enhanced CVD deposition of ZnO: Al layers by focusing on the control

Sulfuric acid dissolution of the Chashma-Sang deposit's green clays

International Nuclear Information System (INIS)

Mirzoev, D.Kh.; Boboev, Kh.E.; Pulatov, M.S.; Mirsaidov, U.M.

2005-01-01

Present article is presenting the results of the roentgen phase, thermodynamic and physical-chemical investigations of the green clays of the Chashma-Sang deposit of the Republic of Tajikistan. It is presented mineralogical and chemical composition of the mineral raw materials. Kinetic of decomposition of the oxides of aluminum and iron on temperature, time and concentration of the sulfuric acid has been investigated

Responses of Soil Acid Phosphomonoesterase Activity to Simulated Nitrogen Deposition in Three Forests of Subtropical China

Institute of Scientific and Technical Information of China (English)

HUANG Wen-Juan; LIU Shi-Zhong; CHU Guo-Wei; ZHANG De-Qiang; LI Yue-Lin; LU Xian-Kai; ZHANG Wei; HUANG Juan; D. OTIENO; Z. H. XU; LIU Ju-Xiu

2012-01-01

Soil acid phosphomonoesterase activity (APA) plays a vital role in controlling phosphorus (P) cycling and reflecting the current degree of P limitation Responses of soil APA to elevating nitrogen (N) deposition are important because of their potential applications in addressing the relationship between N and P in forest ecosystems.A study of responses of soll APA to simulated N deposition was conducted in three succession forests of subtropical China.The three forests include a Masson pine (Pinus massoniana) forest (MPF)—pioneer community,a coniferous and broad-leaved mixed forest (MF)—transition community and a monsoon evergreen broadleaved forest (MEBF)—climax community.Four N treatments were designed for MEBF:control (without N added),low-N (50 kg N ha-1 year-1),and medium-N (100 kg N ha-1 year-1) and high-N (150 kg N ha-1 year-1),and only three N treatments (i.e.,control,low-N,mediun-N) were established for MPF and MF.Results showed that soil APA was highest in MEBF.followed by MPF and MF.Soil APAs in both MPF and MF were not influenced by low-N treatments but depressed in medium-N trcatments.However,soil APA in MEBF exhibited negative responses to high N additions,indicating that the environment of enhanced N depositions would reduce P supply for the mature forest ecosystem.Soil APA and its responses to N additions in subtropical forests were closely related to the succession stages in the forests.

How deposition parameters control growth dynamics of nc-Si deposited by hot-wire chemical vapor deposition

International Nuclear Information System (INIS)

Moutinho, H.R.; To, B.; Jiang, C.-S.; Xu, Y.; Nelson, B.P.; Teplin, C.W.; Jones, K.M.; Perkins, J.; Al-Jassim, M.M.

2006-01-01

We studied the growth of silicon films deposited by hot-wire chemical vapor deposition under different values of filament current, substrate temperature, and hydrogen dilution ratio. The physical and electrical properties of the films were studied by Raman spectroscopy, x-ray diffraction, atomic force microscopy, conductive-atomic force microscopy, and transmission electron microscopy. There is an interdependence of the growth parameters, and films grown with different parameters can have similar structures. We discuss why this interdependence occurs and how it influences the properties of the deposited films, as well as the deposition rate. In general, the films have a complex structure, with a mixture of amorphous (220)-oriented crystalline and nanocrystalline phases present in most cases. The amount of each phase can be controlled by the variation of one or more of the growth parameters at a time

Electrodeposition of ruthenium, rhodium and palladium from nitric acid and ionic liquid media: Recovery and surface morphology of the deposits

Energy Technology Data Exchange (ETDEWEB)

Jayakumar, M.; Venkatesan, K.A.; Sudha, R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Srinivasan, T.G., E-mail: tgs@igcar.gov.com [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India); Vasudeva Rao, P.R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603102 (India)

2011-07-15

Research highlights: {yields} Platinum group metals are man-made noble metals. {yields} Electrochemical recovery of fission platinoids. {yields} Recovery from nitric acid medium. {yields} Recovery from ionic liquid medium. {yields} Platinoids with exotic surface morphologies. - Abstract: Electrodeposition is a promising technique for the recovery of platinum group metals with unique surface morphologies. The electrodeposition of palladium, ruthenium and rhodium from aqueous nitric acid, and non-aqueous 1-butyl-3-methylimidazolium chloride ionic liquid medium was studied at stainless steel electrode. The surface morphology and elemental composition of the resultant deposit were probed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. Deposits with diverse surface morphologies and metal compositions were obtained by varying the composition of the electrolytic medium and applied potential. The results demonstrate the possibility of tailoring the morphologies of PGMs by controlling the composition and potential needed for electrodeposition.

Controlled deposition of functionalized silica coated zinc oxide nano-assemblies at the air/water interface for blood cancer detection

Energy Technology Data Exchange (ETDEWEB)

Pandey, Chandra Mouli [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Nanobioelectronics Laboratory, Department of Biotechnology, Delhi Technological University, Delhi 110042 (India); Dewan, Srishti [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Biomedical Engineering Department, Deenbandhu Chhotu Ram University of Science & Technology, Haryana 131039 (India); Chawla, Seema [Biomedical Engineering Department, Deenbandhu Chhotu Ram University of Science & Technology, Haryana 131039 (India); Yadav, Birendra Kumar [Rajiv Gandhi Cancer Institute and Research Centre, Rohini, Delhi 110085 (India); Sumana, Gajjala, E-mail: sumanagajjala@gmail.com [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Malhotra, Bansi Dhar, E-mail: bansi.malhotra@gmail.com [Biomedical Instrumentation Section, CSIR-National Physical Laboratory, New Delhi 110012 (India); Nanobioelectronics Laboratory, Department of Biotechnology, Delhi Technological University, Delhi 110042 (India)

2016-09-21

We report results of the studies relating to controlled deposition of the amino-functionalized silica-coated zinc oxide (Am-Si@ZnO) nano-assemblies onto an indium tin oxide (ITO) coated glass substrate using Langmuir-Blodgett (LB) technique. The monolayers have been deposited by transferring the spread solution of Am-Si@ZnO stearic acid prepared in chloroform at the air-water interface, at optimized pressure (16 mN/m), concentration (10 mg/ml) and temperature (23 °C). The high-resolution transmission electron microscopic studies of the Am-Si@ZnO nanocomposite reveal that the nanoparticles have a microscopic structure comprising of hexagonal assemblies of ZnO with typical dimensions of 30 nm. The surface morphology of the LB multilayer observed by scanning electron microscopy shows uniform surface of the Am-Si@ZnO film in the nanometer range (<80 nm). These electrodes have been utilized for chronic myelogenous leukemia (CML) detection by covalently immobilizing the amino-terminated oligonucleotide probe sequence via glutaraldehyde as a crosslinker. The response studies of these fabricated electrodes carried out using electrochemical impedance spectroscopy show that this Am-Si@ZnO LB film based nucleic acid sensor exhibits a linear response to complementary DNA (10{sup −6}–10{sup −16} M) with a detection limit of 1 × 10{sup −16} M. This fabricated platform is validated with clinical samples of CML positive patients and the results demonstrate its immense potential for clinical diagnosis. - Graphical abstract: Controlled deposition of functionalized silica coated zinc oxide nano-assemblies at the air/water interface for label free electrochemical detection of chronic myelogenous leukemia. - Highlights: • Stable and controlled deposition of Am-Si@ZnO nano-assemblies using LB technique. • Uniform monolayer deposition of the Am-Si@ZnO LB film within the nanometer range. • Am-Si@ZnO LB film shows enhanced electrochemical properties. • Fabricated

4.3. Decomposition of danburite concentrate of Ak-Arkar Deposit by nitric acid

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to decomposition of danburite concentrate of Ak-Arkar Deposit by nitric acid. The influence of temperature on reaction process was studied. The dependence of extraction rate of oxides (B 2 O 3 , Al 2 O 3 , Fe 2 O 3 and Ca O) at nitric acid processing on temperature ranges from 25 to 95 deg C was defined. The dependence of extraction rate of oxides (B 2 O 3 , Al 2 O 3 , Fe 2 O 3 and Ca O) at nitric acid processing on process duration (5-60 minutes) was defined as well. The optimal conditions of decomposition of danburite concentrate by nitric acid were proposed.

Transport of acid forming emissions and potential effects of deposition in northeastern Alberta and northern Saskatchewan: a problem analysis

Energy Technology Data Exchange (ETDEWEB)

Shewchuk, S.R.; Abouguendia, Z.M.; Atton, F.M.; Dublin, J.; Godwin, R.C.; Holowaychuk, N.; Hopkinson, R.; Liaw, W.K.; Maybank, J.; Padbury, G.A.

1981-01-01

The purpose of this report is to study the potential effects of acid rain in northeastern Alberta and northern Saskatchewan. A problem analysis was conducted of the transport, transformations and deposition of emissions in this region. Studied are the atmospheric processes, geology and soils, natural vegetation, and the aquatic systems. At present, no environmental damage attributable to acidic deposition has been detected in this region. Field surveys in the region have detected no effects of industrial emissions on vegetation except within a few kilometers of industrial operations. The earliest effects of acid deposition tend to appear within aquatic systems. Ten recommendations based on these findings are discussed. 109 references, 22 figures, 10 tables.

Analysis of leachability for a sandstone uranium deposite with high acid consumption and sensitivities in Inner Mongolia

International Nuclear Information System (INIS)

Cheng Wei; Miao Aisheng; Li Jianhua; Zhou Lei; Chang Jingtao

2014-01-01

In-situ Leaching adaptability of a ground water oxidation zone type sandstone uranium deposit from Inner Mongolia is studied. The ore of the uranium deposit has high acid consumption and sensitivities in in-situ leaching. The leaching process with agent of CO_2 + O_2 and adjusting concentration of HCO_3"- can be suitable for the deposit. (authors)

Effect of N deposition on tree amino acid concentrations in two Sphagnum species

Energy Technology Data Exchange (ETDEWEB)

Karsisto, M; Kitunen, V [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H [Helsinki Univ. (Finland). Dept. of Forest Ecology

1997-12-31

Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

Effect of N deposition on tree amino acid concentrations in two Sphagnum species

Energy Technology Data Exchange (ETDEWEB)

Karsisto, M.; Kitunen, V. [Finnish Forest Research Inst., Vantaa (Finland). Vantaa Research Centre; Jauhiainen, J. [Joensuu Univ. (Finland). Dept. of Biology; Vasander, H. [Helsinki Univ. (Finland). Dept. of Forest Ecology

1996-12-31

Nitrogen saturation of ecosystems occurs when the availability of nitrogen is not a growth limiting factor. This situation can be reached through fertilisation or by nitrogen deposition. Prolonged nitrogen saturation may overload the ecosystem and cause changes in the vigour and eventually in the composition of plant communities. But before this stage is reached, certain changes in nitrogen metabolism occur. These changes can be used as an early warning of nitrogen overload to ecosystems. A change in the amino acid pool of plants has been used as an indication of various kind of stress, including, temperature, nutrient imbalance, shading, drought or excess water. It has been postulated that such stresses have an effect on protein synthesis but not on the nitrogen uptake of plants. The result is an increase in the concentration of NH{sub 4}{sup +} ions in plant cells, which may have toxic effects to the plant and the processes that assimilate the free NH{sub 4}{sup +} ions. One of such process is the synthesis of amino acids, especially those containing a significant proportion of nitrogen, e.g. arginine, glutamine and asparagine. This study about the quantification of amino acids in two species of Sphagnum mosses is part of a larger study, the aim of which is to clarify how a number of Sphagnum species will cope with climatic change and nitrogen deposition. Sphagna are the most important members of the peat forming communities in the boreal zone. Sphagnum communities are formed by species specialised to grow in conditions of low nutrient availability, mainly provided via deposition. The present structure and composition of mire communities may be endangered due to elevated levels of nitrogen deposition that have persisted over the last few decades. (20 refs.)

Influence of acidic atmospheric deposition on soil solution composition in the Daniel Boone National Forest, Kentucky, USA

Science.gov (United States)

C.D. Barton; A.D. Karathanasis; G. Chalfant

2002-01-01

Acid atmosperic depositoin may enter an environmental ecosystem in a variety of forms and pathways, but the most common components include sulfuric and nitric acids formed when rainwater interacts with sulfur (SO3) and nitrogen (NO3) emmissions. For many soils and watersheds sensitive to acid deposition, the predominant...

Atmospheric dry and wet deposition of sulphur and nitrogen species and assessment of critical loads of acidic deposition exceedance in South Africa

Directory of Open Access Journals (Sweden)

Stuart J. Piketh

2011-03-01

Full Text Available We tested the hypothesis that acidic atmospheric pollution deposition, originating from the South African central industrial area, poses an environmental threat across a larger region within the dispersal footprint. A network of 37 passive monitoring sites to measure SO₂ and NO₂ was operated from August 2005 to September 2007. The area extended over the entire northern and eastern interior of South Africa. Monitoring locations were chosen to avoid direct impacts from local sources such as towns, mines and highways. Dry deposition rates of SO₂ and NO₂ were calculated from the measured concentrations. Concentrations of sulphur and nitrogen species in wet deposition from a previous study were used in conjunction with measured rainfall for the years 2006 and 2007 to estimate the wet deposition over the region. The calculated total (non-organic acidic deposition formed the basis for an assessment of exceedance of critical loads based on sensitivity of the regional soils. Regional soil sensitivity was determined by combining two major soil attributes available in the World Inventory of Soil Emission Potentials (International Soil Reference and Information Centre. Results indicate that certain parts of the central pollution source area on the South African Highveld have the potential for critical load exceedance, while limited areas downwind show lower levels of exceedance. Areas upwind and remote areas up and downwind, including forested areas of the Drakensberg escarpment, do not show any exceedance of the critical loads.

Effects of acidic deposition on the erosion of carbonate stone - experimental results from the U.S. National Acid Precipitation Assessment Program (NAPAP)

Science.gov (United States)

Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A.

1992-01-01

One of the goals of NAPAP-sponsored research on the effects of acidic deposition on carbonate stone has been to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulfur dioxide and nitrogen oxides on stone erosion. Test briquettes and slabs of freshly quarried Indiana limestone and Vermont marble have been exposed to ambient environmental conditions in a long-term exposure program. Physical measurements of the recession of test stones exposed to ambient conditions at an angle of 30?? to horizontal at the five NAPAP materials exposure sites range from ~15 to ~30?? ??m yr-1 for marble, and from ~25 to ~45 ??m yr -1 for limestone, and are approximately double the recession estimates based on the observed calcium content of run-off solutions from test slabs. The difference between the physical and chemical recession measurements is attributed to the loss of mineral grains from the stone surfaces that are not measured in the run-off experiments. The erosion due to grain loss does not appear to be influenced by rainfall acidity, however, preliminary evidence suggests that grain loss may be influenced by dry deposition of sulfur dioxide between rainfall events. Chemical analyses of the run-off solutions and associated rainfall blanks suggest that ~30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulfur dioxide and nitric acid between rain events. The remaining ~70% of erosion by dissolution is accounted for by the solubility of carbonate stone in rain that is in equilibrium with atmospheric carbon dioxide ('clean rain'). These results are for marble and limestone slabs exposed at an angle of 30?? from horizontal. The relative contribution of sulfur dioxide to chemical erosion is significantly enhanced for stone slabs having an inclination of 60?? or 85??. The dry deposition of alkaline particulate material has a mitigating effect at the two urban field exposure sites at Washington, DC

Defect control in room temperature deposited cadmium sulfide thin films by pulsed laser deposition

International Nuclear Information System (INIS)

Hernandez-Como, N.; Martinez-Landeros, V.; Mejia, I.; Aguirre-Tostado, F.S.; Nascimento, C.D.; Azevedo, G. de M; Krug, C.; Quevedo-Lopez, M.A.

2014-01-01

The control of defects in cadmium sulfide thin films and its impact on the resulting CdS optical and electrical characteristics are studied. Sulfur vacancies and cadmium interstitial concentrations in the CdS films are controlled using the ambient pressure during pulsed laser deposition. CdS film resistivities ranging from 10 −1 to 10 4 Ω-cm are achieved. Hall Effect measurements show that the carrier concentration ranges from 10 19 to 10 13 cm −3 and is responsible for the observed resistivity variation. Hall mobility varies from 2 to 12 cm 2 /V-s for the same pressure regime. Although the energy bandgap remains unaffected (∼ 2.42 eV), the optical transmittance is reduced due to the increase of defects in the CdS films. Rutherford back scattering spectroscopy shows the dependence of the CdS films stoichiometry with deposition pressure. The presence of CdS defects is attributed to more energetic species reaching the substrate, inducing surface damage in the CdS films during pulsed laser deposition. - Highlights: • CdS thin films deposited by pulsed laser deposition at room temperature. • The optical, electrical and structural properties were evaluated. • Carrier concentration ranged from 10 19 to 10 13 cm −3 . • The chemical composition was studied by Rutherford back scattering. • The density of sulfur vacancies and cadmium interstitial was varied

Occurrence and prevention of enhanced oxide deposition in boiler flow control orifices

International Nuclear Information System (INIS)

Woolsey, I.S.; Thomas, D.M.; Garbett, K.; Bignold, G.J.

1989-10-01

Once-through boilers, such as those of the AGRs, incorporate flow control orifices at the boiler inlet to ensure a satisfactory flow distribution and stability in the parallel flow paths of the boiler. Deposition of corrosion products in the flow control orifice leads to changes in the orifice pressure loss characteristics, which could lead to problems of flow maldistribution within the boiler, and any adverse consequences resulting from this, such as tube overheating. To date, AGR boiler inlet orifices have not suffered significant fouling due to corrosion products in the boiler feedwater. However, oxide deposition in orifices has been observed in other plants, and in experimental loops operating under conditions very similar to those at inlet to AGR boilers. The lack of deposition in AGR flow control orifices is therefore somewhat surprising. This Report describes studies carried out to examine the factors controlling oxide deposition in flow control orifices, the intention of the work being to explain why deposition has not occurred in AGR boilers to date, and to provide means of preventing deposition in the future should this prove necessary. (author)

Interface control of atomic layer deposited oxide coatings by filtered cathodic arc deposited sublayers for improved corrosion protection

Energy Technology Data Exchange (ETDEWEB)

Härkönen, Emma, E-mail: emma.harkonen@helsinki.fi [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland); Tervakangas, Sanna; Kolehmainen, Jukka [DIARC-Technology Inc., Espoo (Finland); Díaz, Belén; Światowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe [Laboratoire de Physico-Chimie des Surfaces, CNRS (UMR 7075) – Chimie ParisTech (ENSCP), F-75005 Paris (France); Fenker, Martin [FEM Research Institute, Precious Metals and Metals Chemistry, D-73525 Schwäbisch Gmünd (Germany); Tóth, Lajos; Radnóczi, György [Research Centre for Natural Sciences HAS, (MTA TKK), Budapest (Hungary); Ritala, Mikko [Laboratory of Inorganic Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki (Finland)

2014-10-15

Sublayers grown with filtered cathodic arc deposition (FCAD) were added under atomic layer deposited (ALD) oxide coatings for interface control and improved corrosion protection of low alloy steel. The FCAD sublayer was either Ta:O or Cr:O–Ta:O nanolaminate, and the ALD layer was Al{sub 2}O{sub 3}–Ta{sub 2}O{sub 5} nanolaminate, Al{sub x}Ta{sub y}O{sub z} mixture or graded mixture. The total thicknesses of the FCAD/ALD duplex coatings were between 65 and 120 nm. Thorough analysis of the coatings was conducted to gain insight into the influence of the FCAD sublayer on the overall coating performance. Similar characteristics as with single FCAD and ALD coatings on steel were found in the morphology and composition of the duplex coatings. However, the FCAD process allowed better control of the interface with the steel by reducing the native oxide and preventing its regrowth during the initial stages of the ALD process. Residual hydrocarbon impurities were buried in the interface between the FCAD layer and steel. This enabled growth of ALD layers with improved electrochemical sealing properties, inhibiting the development of localized corrosion by pitting during immersion in acidic NaCl and enhancing durability in neutral salt spray testing. - Highlights: • Corrosion protection properties of ALD coatings were improved by FCAD sublayers. • The FCAD sublayer enabled control of the coating-substrate interface. • The duplex coatings offered improved sealing properties and durability in NSS. • The protective properties were maintained during immersion in a corrosive solution. • The improvements were due to a more ideal ALD growth on the homogeneous FCAD oxide.

Impact of acid atmospheric deposition on soils : quantification of chemical and hydrologic processes

NARCIS (Netherlands)

Grinsven, van J.J.M.

1988-01-01

Atmospheric deposition of SO _x , NOx and NHx will cause major changes in the chemical composition of solutions in acid soils, which may affect the biological functions of the soil. This thesis deals with quantification of soil acidification by means of chemical

Microcrystalline silicon deposition: Process stability and process control

International Nuclear Information System (INIS)

Donker, M.N. van den; Kilper, T.; Grunsky, D.; Rech, B.; Houben, L.; Kessels, W.M.M.; Sanden, M.C.M. van de

2007-01-01

Applying in situ process diagnostics, we identified several process drifts occurring in the parallel plate plasma deposition of microcrystalline silicon (μc-Si:H). These process drifts are powder formation (visible from diminishing dc-bias and changing spatial emission profile on a time scale of 10 0 s), transient SiH 4 depletion (visible from a decreasing SiH emission intensity on a time scale of 10 2 s), plasma heating (visible from an increasing substrate temperature on a time scale of 10 3 s) and a still puzzling long-term drift (visible from a decreasing SiH emission intensity on a time scale of 10 4 s). The effect of these drifts on the crystalline volume fraction in the deposited films is investigated by selected area electron diffraction and depth-profiled Raman spectroscopy. An example shows how the transient depletion and long-term drift can be prevented by suitable process control. Solar cells deposited using this process control show enhanced performance. Options for process control of plasma heating and powder formation are discussed

Effects of acidic deposition and soil acidification on sugar maple trees in the Adirondack Mountains, New York

Science.gov (United States)

Sullivan, Timothy J.; Lawrence, Gregory B.; Bailey, Scott W.; McDonnell, Todd C.; Beier, Colin M.; Weathers, K.C.; McPherson, G.T.; Bishop, Daniel A.

2013-01-01

We documented the effects of acidic atmospheric deposition and soil acidification on the canopy health, basal area increment, and regeneration of sugar maple (SM) trees across the Adirondack region of New York State, in the northeastern United States, where SM are plentiful but not well studied and where widespread depletion of soil calcium (Ca) has been documented. Sugar maple is a dominant canopy species in the Adirondack Mountain ecoregion, and it has a high demand for Ca. Trees in this region growing on soils with poor acid–base chemistry (low exchangeable Ca and % base saturation [BS]) that receive relatively high levels of atmospheric sulfur and nitrogen deposition exhibited a near absence of SM seedling regeneration and lower crown vigor compared with study plots with relatively high exchangeable Ca and BS and lower levels of acidic deposition. Basal area increment averaged over the 20th century was correlated (p < 0.1) with acid–base chemistry of the Oa, A, and upper B soil horizons. A lack of Adirondack SM regeneration, reduced canopy condition, and possibly decreased basal area growth over recent decades are associated with low concentrations of nutrient base cations in this region that has undergone soil Ca depletion from acidic deposition.

Long-term changes in soil and stream chemistry across an acid deposition gradient in the northeastern United States

Science.gov (United States)

Siemion, Jason; McHale, Michael; Lawrence, Gregory B.; Burns, Douglas A.; Antidormi, Michael

2018-01-01

Declines in acidic deposition across Europe and North America have led to decreases in surface water acidity and signs of chemical recovery of soils from acidification. To better understand the link between recovery of soils and surface waters, chemical trends in precipitation, soils, and streamwater were investigated in three watersheds representing a depositional gradient from high to low across the northeastern United States. Significant declines in concentrations of H+ (ranging from −1.2 to −2.74 microequivalents [μeq] L−1 yr−1), NO3− (ranging from −0.6 to −0.84 μeq L−1 yr−1), and SO42− (ranging from −0.95 to −2.13 μeq L−1 yr−1) were detected in precipitation in the three watersheds during the period 1999 to 2013. Soil chemistry in the A horizon of the watershed with the greatest decrease in deposition showed significant decreases in exchangeable Al and increases in exchangeable bases. Soil chemistry did not significantly improve during the study in the other watersheds, and base saturation in the Oa and upper B horizons significantly declined in the watershed with the smallest decrease in deposition. Streamwater SO42−concentrations significantly declined in all three streams (ranging from −2.01 to −2.87 μeq L−1 yr−1) and acid neutralizing capacity increased (ranging from 1.38 to 1.60 μeq L−1 yr−1) in the two streams with the greatest decreases in deposition. Recovery of soils has likely been limited by decades of acid deposition that have leached base cations from soils with base-poor parent material.

Acid Deposition Maps in Spain

International Nuclear Information System (INIS)

Artinano, B.; Cabal, H.; Garcia, C.

1998-01-01

Animal and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To do this, updated databases with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5x5 Km 2 grid which allow to assess the methodology used in Europe to obtain the maps of excedances over the critical loads of pollutants. (Author) 32 refs

Sputter deposition system for controlled fabrication of multilayers

International Nuclear Information System (INIS)

Di Nardo, R.P.; Takacs, P.Z.; Majkrzak, C.F.; Stefan, P.M.

1985-06-01

A detailed description of a sputter deposition system constructed specifically for the fabrication of x-ray and neutron multilayer monochromators and supermirrors is given. One of the principal design criteria is to maintain precise control of film thickness and uniformity over large substrate areas. Regulation of critical system parameters is fully automated so that response to feedback control information is rapid and complicated layer thickness sequences can be deposited accurately and efficiently. The use of either dc or rf magnetron sources makes it possible to satisfy the diverse material requirements of both x-ray and neutron optics

Defect control in room temperature deposited cadmium sulfide thin films by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Hernandez-Como, N. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Martinez-Landeros, V. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Centro de Investigación en Materiales Avanzados, Monterrey, Nuevo Leon, 66600, México (Mexico); Mejia, I. [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States); Aguirre-Tostado, F.S. [Centro de Investigación en Materiales Avanzados, Monterrey, Nuevo Leon, 66600, México (Mexico); Nascimento, C.D.; Azevedo, G. de M; Krug, C. [Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91509-900 (Brazil); Quevedo-Lopez, M.A., E-mail: mquevedo@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX, 75080 (United States)

2014-01-01

The control of defects in cadmium sulfide thin films and its impact on the resulting CdS optical and electrical characteristics are studied. Sulfur vacancies and cadmium interstitial concentrations in the CdS films are controlled using the ambient pressure during pulsed laser deposition. CdS film resistivities ranging from 10{sup −1} to 10{sup 4} Ω-cm are achieved. Hall Effect measurements show that the carrier concentration ranges from 10{sup 19} to 10{sup 13} cm{sup −3} and is responsible for the observed resistivity variation. Hall mobility varies from 2 to 12 cm{sup 2}/V-s for the same pressure regime. Although the energy bandgap remains unaffected (∼ 2.42 eV), the optical transmittance is reduced due to the increase of defects in the CdS films. Rutherford back scattering spectroscopy shows the dependence of the CdS films stoichiometry with deposition pressure. The presence of CdS defects is attributed to more energetic species reaching the substrate, inducing surface damage in the CdS films during pulsed laser deposition. - Highlights: • CdS thin films deposited by pulsed laser deposition at room temperature. • The optical, electrical and structural properties were evaluated. • Carrier concentration ranged from 10{sup 19} to 10{sup 13} cm{sup −3}. • The chemical composition was studied by Rutherford back scattering. • The density of sulfur vacancies and cadmium interstitial was varied.

Analysis of potential combustion source impacts on acid deposition using an independently derived inventory. Volume I

Energy Technology Data Exchange (ETDEWEB)

1983-12-01

This project had three major objectives. The first objective was to develop a fossil fuel combustion source inventory (NO/sub x/, SO/sub x/, and hydrocarbon emissions) that would be relatively easy to use and update for analyzing the impact of combustion emissions on acid deposition in the eastern United States. The second objective of the project was to use the inventory data as a basis for selection of a number of areas that, by virtue of their importance in the acid rain issue, could be further studied to assess the impact of local and intraregional combustion sources. The third objective was to conduct an analysis of wet deposition monitoring data in the areas under study, along with pertinent physical characteristics, meteorological conditions, and emission patterns of these areas, to investigate probable relationships between local and intraregional combustion sources and the deposition of acidic material. The combustion source emissions inventory has been developed for the eastern United States. It characterizes all important area sources and point sources on a county-by-county basis. Its design provides flexibility and simplicity and makes it uniquely useful in overall analysis of emission patterns in the eastern United States. Three regions with basically different emission patterns have been identified and characterized. The statistical analysis of wet deposition monitoring data in conjunction with emission patterns, wind direction, and topography has produced consistent results for each study area and has demonstrated that the wet deposition in each area reflects the characteristics of the localized area around the monitoring sites (typically 50 to 150 miles). 8 references, 28 figures, 39 tables.

Effects of acidic deposition on the erosion of carbonate stone — experimental results from the U.S. National Acid Precipitation Assessment Program (NAPAP)

Science.gov (United States)

Baedecker, Philip A.; Reddy, Michael M.; Reimann, Karl J.; Sciammarella, Cesar A.

One of the goals of NAPAP-sponsored research on the effects of acidic deposition on carbonate stone has been to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulfur dioxide and nitrogen oxides on stone erosion. Test briquettes and slabs of freshly quarried Indiana limestone and Vermont marble have been exposed to ambient environmental conditions in a long-term exposure program. Physical measurements of the recession of test stones exposed to ambient conditions at an angle of 30° to horizontal at the five NAPAP materials exposure sites range from ˜ 15 to ˜ 30 μm yr -1 for marble, and from ˜ 25 to ˜ 45 μm yr -1 for limestone, and are approximately double the recession estimates based on the observed calcium content of run-off solutions from test slabs. The difference between the physical and chemical recession measurements is attributed to the loss of mineral grains from the stone surfaces that are not measured in the run-off experiments. The erosion due to grain loss does not appear to be influenced by rainfall acidity, however, preliminary evidence suggests that grain loss may be influenced by dry deposition of sulfur dioxide between rainfall events. Chemical analyses of the run-off solutions and associated rainfall blanks suggest that ˜ 30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulfur dioxide and nitric acid between rain events. The remaining ˜ 70% of erosion by dissolution is accounted for by the solubility of carbonate stone in rain that is in equilibrium with atmospheric carbon dioxide ("clean rain"). These results are for marble and limestone slabs exposed at an angle of 30° from horizontal. The relative contribution of sulfur dioxide to chemical erosion is significantly enhanced for stone slabs having an inclination of 60° or 85°. The dry deposition of alkaline particulate material has a mitigating effect at the two urban field exposure sites at

1.6. The kinetics of hydrochloric acid decomposition of argillite of Chashma-Sang Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Mirzoev, D.Kh.; Boboev, Kh.E.

2016-01-01

Present article of book is devoted to kinetics of hydrochloric acid decomposition of argillite of Chashma-Sang Deposit. It was defined that with temperature increasing the extraction rate of Al_2O_3 and Fe_2O_3 increases. The dependence of extraction rate of Al_2O_3 and Fe_2O_3 on process duration at hydrochloric acid decomposition of argillite was studied. The activation energy of the process was defined.

Scalable control program for multiprecursor flow-type atomic layer deposition system

Energy Technology Data Exchange (ETDEWEB)

Selvaraj, Sathees Kannan [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); Takoudis, Christos G., E-mail: takoudis@uic.edu [Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607 and Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois 60607 (United States)

2015-01-01

The authors report the development and implementation of a scalable control program to control flow type atomic layer deposition (ALD) reactor with multiple precursor delivery lines. The program logic is written and tested in LABVIEW environment to control ALD reactor with four precursor delivery lines to deposit up to four layers of different materials in cyclic manner. The programming logic is conceived such that to facilitate scale up for depositing more layers with multiple precursors and scale down for using single layer with any one precursor in the ALD reactor. The program takes precursor and oxidizer exposure and purging times as input and controls the sequential opening and closing of the valves to facilitate the complex ALD process in cyclic manner. The program could be used to deposit materials from any single line or in tandem with other lines in any combination and in any sequence.

Recent Advances in Controlling the Depositing Morphologies of Inkjet Droplets.

Science.gov (United States)

Sun, Jiazhen; Bao, Bin; He, Min; Zhou, Haihua; Song, Yanlin

2015-12-30

Inkjet printing has been widely used in functional material patterning for fabrication of optical/electrical devices. The depositing morphologies of inkjet droplets are critical to the resolution and performance of resulted functional patterns. This review summarizes various strategies to control the depositing morphologies of inkjet droplets, including suppressing and utilizing coffee-ring effect, employing liquid substrates, developing patterned substrates and controlling droplets coalescence. Moreover, the remaining challenges in controlling inkjet droplets are presented, and the broad research and application prospects of controlling nanomaterial patterning by inkjet printing are proposed.

Hatching success in salamanders and chorus frogs at two sites in Colorado, USA: Effects of acidic deposition and climate

Science.gov (United States)

Muths, E.; Campbell, D.H.; Corn, P.S.

2003-01-01

The snowpack in the vicinity of the Mount Zirkel Wilderness Area is among the most acidic in the western United States. We analyzed water chemistry and examined hatching success in tiger salamanders and chorus frogs at ponds there and at nearby Rabbit Ears Pass (Dumont) to determine whether acid deposition affects amphibians or their breeding habitats at these potentially sensitive locations. We found a wide range of acid neutralizing capacity among ponds within sites; the minimum pH recorded during the experiment was 5.4 at one of 12 ponds with all others at pH ??? 5.7. At Dumont, hatching success for chorus frogs was greater in ponds with low acid neutralizing capacity; however, lowest pHs were >5.8. At current levels of acid deposition, weather and pond characteristics are likely more important than acidity in influencing hatching success in amphibian larvae at these sites.

Recovery of fission products from acidic waste solutions thereof

International Nuclear Information System (INIS)

Carlin, W.W.; Darlington, W.B.; Dubois, D.W.

1975-01-01

Fission products, e.g., palladium, ruthenium and technetium, are removed from aqueous, acidic waste solutions thereof. The acidic waste solution is electrolyzed in an electrolytic cell under controlled cathodic potential conditions and technetium, ruthenium, palladium and rhodium are deposited on the cathode. Metal deposit is removed from the cathode and dissolved in acid. Acid insoluble rhodium metal is recovered, dissolved by alkali metal bisulfate fusion and purified by electrolysis. In one embodiment, the solution formed by acid dissolution of the cathode metal deposit is treated with a strong oxidizing agent and distilled to separate technetium and ruthenium (as a distillate) from palladium. Technetium is separated from ruthenium by organic solvent extraction and then recovered, e.g., as an ammonium salt. Ruthenium is disposed of as waste by-product. Palladium is recovered by electrolysis of an acid solution thereof under controlled cathodic potential conditions. Further embodiments wherein alternate metal recovery sequences are used are described. (U.S.)

Laboratory study on leaching of a sandstone-type uranium deposit for acid in-situ leaching

International Nuclear Information System (INIS)

Wen Zhenqian; Yao Yixuan; Zheng Jianping; Jiang Yan; Cui Xin; Xing Yongguo; Hao Jinting; Tang Huazhang

2013-01-01

Ore samples were took from in-situ leaching experiment boreholes in a sandstone-type uranium deposit. Technological mineralogy study, agitating leaching and column leaching experiments were carried. The results show that the content of minerals consuming acid and deoxidized minerals is low. When sulfuric acid concentration was 1O g/L, initial uranium content was 0.0224%, and liquid-to-solid ratio was l.91, leaching rate of column leaching experiments is 89.19%, acid consumption is 8.2 kg/t ore, acid consumption is 41.88 t/tU. Acid leaching, technology is recommend for field in-situ leaching experiment, sulfuric acid concentration in confecting solution is 10 g/L, and oxidizing agent is needless during leaching process. (authors)

Changing public interest in, and awareness of, acid deposition: some evidence from the UK

International Nuclear Information System (INIS)

Longhurst, J.W.S.; Bantock, J.; Hare, S.E.; Conlan, D.E.

1995-01-01

It is fundamental that the general public have access to usable environmental information on which they can base their decisions. Since 1984 the Atmospheric Research and Information Centre (ARIC) has operated a public information programme for the UK on the subject of acid deposition. The objective of the programme is to disseminate information on acid deposition without advocacy. ARIC provides enquiries with a broad range of authoritative and accurate facts and opinions from a wide range of parties from all sides of the debate. These sources include pressure groups, governmental bodies and industrialists from the UK and overseas. By deconstructing complex technical material and reassembling it for dissemination in a user friendly form, ARIC assists those receiving information to obtain a balanced perspective. This enables personal decision making within the context of the fullest information resource ARIC is able to provide. 8 refs., 4 tabs

Changing public interest in, and awareness of, acid deposition: some evidence from the UK

Energy Technology Data Exchange (ETDEWEB)

Longhurst, J.W.S.; Bantock, J.; Hare, S.E.; Conlan, D.E. [Manchester Metropolitan University, Manchester (United Kingdom). Dept. of Environmental and Geographical Sciences

1995-12-01

It is fundamental that the general public have access to usable environmental information on which they can base their decisions. Since 1984 the Atmospheric Research and Information Centre (ARIC) has operated a public information programme for the UK on the subject of acid deposition. The objective of the programme is to disseminate information on acid deposition without advocacy. ARIC provides enquiries with a broad range of authoritative and accurate facts and opinions from a wide range of parties from all sides of the debate. These sources include pressure groups, governmental bodies and industrialists from the UK and overseas. By deconstructing complex technical material and reassembling it for dissemination in a user friendly form, ARIC assists those receiving information to obtain a balanced perspective. This enables personal decision making within the context of the fullest information resource ARIC is able to provide. 8 refs., 4 tabs.

The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA.

Science.gov (United States)

McHale, Michael R; Burns, Douglas A; Siemion, Jason; Antidormi, Michael R

2017-10-01

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO 4 2- ) concentrations (mean trend of -2.5 μeq L -1 yr -1 ); hydrogen ion (H + ) and inorganic monomeric aluminum (Al im ) also decreased significantly (mean trends of -0.3 μeq L -1 yr -1 for H + and -0.1 μeq L -1 yr -1 for Al im for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L -1 yr -1 for all 5 sites, which was 4 fold less than the decrease in SO 4 2- concentrations. These upward trends in ANC were limited by coincident decreases in base cations (-1.3 μeq L -1 yr -1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO 3 - ) concentrations despite significant decreasing trends in NO 3 - wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (-0.2 μeq L -1 yr -1 ) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations. Published by Elsevier Ltd.

Evaluation of physical and chemical properties and their interactions in fat, oil, and grease (FOG) deposits.

Science.gov (United States)

Gross, Martin A; Jensen, Jeanette L; Gracz, Hanna S; Dancer, Jens; Keener, Kevin M

2017-10-15

Fat, oil and grease (FOG) blockages in sewer systems are a substantial problem in the United States. It has been estimated that over 50% of sewer overflows are a result of FOG blockages. In this work, a thorough laboratory study was undertaken to examine key variables that contribute to FOG deposit formation under controlled conditions. Physical and chemical properties and their interactions were evaluated and conditions that generated deposits that mimicked field FOG deposits were identified. It was found that 96 of the of 128 reaction conditions tested in the laboratory formed FOG deposits with similar physical and chemical characteristics as field FOG deposits. It was also found that FOG deposits can be created through fatty acid crystallization and not just saponification. Furthermore FOG deposits were found to be more complex than previously documented and contain free fatty acids, fatty acid metal salts, triacylglycerol's, diacylglycerol's and, monoacylglycerol's. Lastly it was found that FOG deposits that only contained saturated fatty acids were on average 2.1 times higher yield strength than deposits that contained unsaturated fatty acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat transfer surfaces

International Nuclear Information System (INIS)

Burgmayer, P.; Crovetto, R.; Turner, C.; Klimas, S.

1998-01-01

The effectiveness of three different dispersants - a polyphosphonic acid (PIPPA); a polymethacrylic acid (PMA); and a hydroxyethylidene methacrylic acid (HEME) - at controlling magnetite deposition has been examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products with a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using a 59-Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any impact on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat-transfer surfaces

International Nuclear Information System (INIS)

Burgmayer, P.; Crovetto, R.; Turner, C.; Klimas, S.J.

1999-07-01

The effectiveness of 3 different dispersants-a polyphosphonic acid (PIPPA), a polymethacrylic acid (PMA), and a hydroxyethylidene methacrylic acid (HEME)-at controlling magnetite deposition was examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products of a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using an 59 Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any effect on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat transfer surfaces

Energy Technology Data Exchange (ETDEWEB)

Burgmayer, P.; Crovetto, R. [Betz Dearborn Labs., Revose, PA (United States); Turner, C.; Klimas, S. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

1998-07-01

The effectiveness of three different dispersants - a polyphosphonic acid (PIPPA); a polymethacrylic acid (PMA); and a hydroxyethylidene methacrylic acid (HEME) - at controlling magnetite deposition has been examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products with a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using a 59-Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any impact on deposition under single-phase forced-convective flow. (author)

Effectiveness of selected dispersants on magnetite deposition at simulated PWR heat-transfer surfaces

Energy Technology Data Exchange (ETDEWEB)

Burgmayer, P.; Crovetto, R. [Betz Dearborn Labs., Revose, PA (United States); Turner, C.; Klimas, S.J

1999-07-01

The effectiveness of 3 different dispersants-a polyphosphonic acid (PIPPA), a polymethacrylic acid (PMA), and a hydroxyethylidene methacrylic acid (HEME)-at controlling magnetite deposition was examined under steam generator operating conditions. Tests in a cycling research model boiler showed that the dispersants resulted in corrosion products of a smaller average size and a bimodal size distribution. At a concentration in the boiler of 10 mg/kg, density weight deposit on heated probes was reduced 4-, 3-, and 2-fold for PMA, PIPPA, and HEME, respectively. PIPPA was the most effective at increasing iron transport out of the boiler. In deposition loop tests using an {sup 59}Fe radiotracer, only PIPPA and HEME were effective at reducing the particle deposition rate under flow-boiling conditions. None of the dispersants had any effect on deposition under single-phase forced-convective flow. (author)

Assessment of lake sensitivity to acidic deposition in national parks of the Rocky Mountains

Science.gov (United States)

Nanus, L.; Williams, M.W.; Campbell, D.H.; Tonnessen, K.A.; Blett, T.; Clow, D.W.

2009-01-01

The sensitivity of high-elevation lakes to acidic deposition was evaluated in five national parks of the Rocky Mountains based on statistical relations between lake acid-neutralizing capacity concentrations and basin characteristics. Acid-neutralizing capacity (ANC) of 151 lakes sampled during synoptic surveys and basin-characteristic information derived from geographic information system (GIS) data sets were used to calibrate the statistical models. The explanatory basin variables that were considered included topographic parameters, bedrock type, and vegetation type. A logistic regression model was developed, and modeling results were cross-validated through lake sampling during fall 2004 at 58 lakes. The model was applied to lake basins greater than 1 ha in area in Glacier National Park (n = 244 lakes), Grand Teton National Park (n = 106 lakes), Great Sand Dunes National Park and Preserve (n = 11 lakes), Rocky Mountain National Park (n = 114 lakes), and Yellowstone National Park (n = 294 lakes). Lakes that had a high probability of having an ANC concentration 3000 m, with 80% of the catchment bedrock having low buffering capacity. The modeling results indicate that the most sensitive lakes are located in Rocky Mountain National Park and Grand Teton National Park. This technique for evaluating the lake sensitivity to acidic deposition is useful for designing long-term monitoring plans and is potentially transferable to other remote mountain areas of the United States and the world.

Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

Science.gov (United States)

Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

2014-01-01

Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

DEFF Research Database (Denmark)

Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas

2016-01-01

The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography......, and magnetic resonance imaging allowing a resolved orientation of the fibers and distribution within the part. The research contributes to the understanding of the fiber orientation and fiber reinforcement of fused deposition modeling parts in additive manufacturing....

Block Copolymer Patterns as Templates for the Electrocatalyzed Deposition of Nanostructures on Electrodes and for the Generation of Surfaces of Controlled Wettability.

Science.gov (United States)

Chandaluri, Chanchayya Gupta; Pelossof, Gilad; Tel-Vered, Ran; Shenhar, Roy; Willner, Itamar

2016-01-20

ITO electrodes modified with a nanopatterned film of polystyrene-block-poly(2-vinylpyridine), PS-b-P2VP, where the P2VP domains are quaternized with iodomethane, are used for selective deposition of redox-active materials. Electrochemical studies (cyclic voltammetry, Faradaic impedance measurements) indicate that the PS domains insulate the conductive surface toward redox labels in solution. In turn, the quaternized P2VP domains electrostatically attract negatively charged redox labels solubilized in the electrolyte solution, resulting in an effective electron transfer between the electrode and the redox label. This phenomenon is implemented for the selective deposition of the electroactive Prussian blue on the nanopatterned surface and for the electrochemical deposition of Au nanoparticles, modified with a monolayer of p-aminothiophenol/2-mercaptoethanesulfonic acid, on the quaternized P2VP domains. The patterned Prussian blue-modified surface enables controlling the wettability properties by the content of the electrochemically deposited Prussian blue. Controlled wettability is unattainable with the homopolymer-modified surface, attesting to the role of the nanopattern.

Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars

Science.gov (United States)

Baldridge, A.M.; Hook, S.J.; Crowley, J.K.; Marion, G.M.; Kargel, J.S.; Michalski, J.L.; Thomson, B.J.; de Souza, Filho C.R.; Bridges, N.T.; Brown, A.J.

2009-01-01

Studies of the origin of the Martian sulfate and phyllosilicate deposits have led to the hypothesis that there was a marked, global-scale change in the Mars environment from circum-neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to Hesperian. However, terrestrial studies suggest that two different geochemical systems need not be invoked to explain such geochemical variation.Western Australian acidic playa lakes have large pH differences separated vertically and laterally by only a few tens of meters, demonstrating how highly variable chemistries can coexist over short distances in natural environments. We suggest diverse and variable Martian aqueous environments where the coetaneous formation of phyllosilicates and sulfates at the Australian sites are analogs for regions where phyllosilicates and sulfates coexist on Mars. In these systems, Fe and alkali earth phyllosilicates represent deep facies associated with upwelling neutral to alkaline groundwater, whereas aluminous phyllosilicates and sulfates represent near-surface evaporitic facies formed from more acidic brines. Copyright 2009 by the American Geophysical Union.

Economic valuation of acidic deposition damages: Preliminary results from the 1985 NAPAP [National Acid Precipitation Assessment Program] damage assessment

International Nuclear Information System (INIS)

Callaway, J.M.; Darwin, R.F.; Nesse, R.J.

1985-01-01

This paper identifies methods used to evaluate the economic damages of acid deposition in the 1985 Damage Assessment being coordinated by the National Acid Precipitation Program. It also presents the preliminary estimates of economic damages for the Assessment. Economic damages are estimated for four effect areas: commercial agriculture and forests, recreational fishing and selected types of materials. In all but the last area, methods are used which incorporate the behavioral responses of individuals and firms or simulated physical damages to resources at risk. The preliminary nature of the estimated damages in each area is emphasized. Over all, the damage estimates should be interpreted with caution. 44 refs., 6 figs., 5 tabs

Effects of decreasing acid deposition and climate change on acid extremes in an upland stream

Directory of Open Access Journals (Sweden)

C. D. Evans

2008-03-01

Full Text Available This study assesses the major chemical processes leading to acid extremes in a small, moorland stream in mid-Wales, UK, which has been monitored since 1979. Results suggest that base cation (mainly calcium dilution, the "sea-salt effect", and elevated nitrate pulses, are the major causes of seasonal/episodic minima in acid neutralising capacity (ANC, and that the relative importance of these drivers has remained approximately constant during 25 years of decreasing acid deposition and associated long-term chemical recovery. Many of the chemical variations causing short-term reductions in stream acidity, particularly base cation dilution and organic acid increases, are closely related to changes in water-flowpath and therefore to stream discharge. Changes in the observed pH-discharge relationship over time indicate that high-flow pH has increased more rapidly than mean-flow pH, and therefore that episodes have decreased in magnitude since 1980. However a two-box application of the dynamic model MAGIC, whilst reproducing this trend, suggests that it will not persist in the long term, with mean ANC continuing to increase until 2100, but the ANC of the upper soil (the source of relatively acid water during high-flow episodes stabilising close to zero beyond 2030. With climate change predicted to lead to an increase in maximum flows in the latter half of the century, high-flow related acid episodes may actually become more rather than less severe in the long term, although the model suggests that this effect may be small. Two other predicted climatic changes could also detrimentally impact on acid episodes: increased severity of winter "sea-salt" episodes due to higher wind speeds during winter storms; and larger sulphate pulses due to oxidation of reduced sulphur held in organic soils, during more extreme summer droughts. At the Gwy, the near-coastal location and relatively small extent of peat soils suggest that sea-salt episodes may have the

Photocatalytic activity of tin-doped TiO{sub 2} film deposited via aerosol assisted chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Chua, Chin Sheng, E-mail: cschua@simtech.a-star.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore); Tan, Ooi Kiang; Tse, Man Siu [School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Ding, Xingzhao [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 (Singapore)

2013-10-01

Tin-doped TiO{sub 2} films are deposited via aerosol assisted chemical vapor deposition using a precursor mixture composing of titanium tetraisopropoxide and tetrabutyl tin. The amount of tin doping in the deposited films is controlled by the volume % concentration ratio of tetrabutyl tin over titanium tetraisopropoxide in the mixed precursor solution. X-ray diffraction analysis results reveal that the as-deposited films are composed of pure anatase TiO{sub 2} phase. Red-shift in the absorbance spectra is observed attributed to the introduction of Sn{sup 4+} band states below the conduction band of TiO{sub 2}. The effect of tin doping on the photocatalytic property of TiO{sub 2} films is studied through the degradation of stearic acid under UV light illumination. It is found that there is a 10% enhancement on the degradation rate of stearic acid for the film with 3.8% tin doping in comparison with pure TiO{sub 2} film. This improvement of photocatalytic performance with tin incorporation could be ascribed to the reduction of electron-hole recombination rate through charge separation and an increased amount of OH radicals which are crucial for the degradation of stearic acid. Further increase in tin doping results in the formation of recombination site and large anatase grains, which leads to a decrease in the degradation rate. - Highlights: ► Deposition of tin-doped TiO{sub 2} film via aerosol assisted chemical vapor deposition ► Deposited anatase films show red-shifted in UV–vis spectrum with tin-dopants. ► Photoactivity improves at low tin concentration but reduces at higher concentration. ► Improvement in photoactivity due to bandgap narrowing from Sn{sup 4+} band states ► Maximum photoactivity achieved occurs for films with 3.8% tin doping.

The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA

Science.gov (United States)

McHale, Michael; Burns, Douglas A.; Siemion, Jason; Antidormi, Michael

2017-01-01

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO42−) concentrations (mean trend of −2.5 μeq L−1 yr−1); hydrogen ion (H+) and inorganic monomeric aluminum (Alim) also decreased significantly (mean trends of −0.3 μeq L−1 yr−1 for H+ and −0.1 μeq L−1 yr−1 for Alim for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L−1 yr−1 for all 5 sites, which was 4 fold less than the decrease in SO42−concentrations. These upward trends in ANC were limited by coincident decreases in base cations (−1.3 μeq L−1 yr−1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO3−) concentrations despite significant decreasing trends in NO3− wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (−0.2 μeq L−1 yr−1) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations.

Effects of acid deposition on tree roots

Energy Technology Data Exchange (ETDEWEB)

Persson, H. [Swedish Univ. of Agricultural Sciences (Sweden). Dept. of Ecology and Environmental Research

1995-12-31

Large forest regions in SW Sweden have been exposed to high levels of acid deposition for many decades, causing soil acidification in forest soils. Historically, SO{sub 2} has been the major acidification agent, but lately nitrogen compounds increasingly have become important. The amount and chemical form of nitrogen strongly affects the pH in the rhizosphere and rhizoplane. Many forest stands show a positive growth response to increased nitrogen input, even in heavily N-loaded areas. Nitrogen fertilization experiments suggest that part of the increased forest production is caused by a translocation of biomass production from below-ground to above-ground parts. At the same time fine-root growth dynamics are strongly affected by the high N supply. Deficiencies of various nutrients (Mg,Ca,K,Mn and Zn) obtained from needle analyses have been reported from different Picea abies stands. In areas with more extensive acidification and nutrient leaching, a decline in tree vitality has been observed. Although deficiency symptoms in forest trees may be reflected in nitrogen/cation ratios in fine roots, few attempts have been made to explain forest damage symptoms from fine-root chemistry. Root damage is often described as a decline in the amount of living fine roots, an increase in the amount of dead versus live fine roots (a lower live/dead ratio) and an increasing amount of dead medium and coarse roots. The primary objectives of the present presentation were to analyse available data on the effects of high nitrogen and sulphur deposition on mineral nutrient balance in tree fine roots and to evaluate the risk of Al interference with cation uptake by roots

Effects of acid deposition on tree roots

Energy Technology Data Exchange (ETDEWEB)

Persson, H [Swedish Univ. of Agricultural Sciences (Sweden). Dept. of Ecology and Environmental Research

1996-12-31

Large forest regions in SW Sweden have been exposed to high levels of acid deposition for many decades, causing soil acidification in forest soils. Historically, SO{sub 2} has been the major acidification agent, but lately nitrogen compounds increasingly have become important. The amount and chemical form of nitrogen strongly affects the pH in the rhizosphere and rhizoplane. Many forest stands show a positive growth response to increased nitrogen input, even in heavily N-loaded areas. Nitrogen fertilization experiments suggest that part of the increased forest production is caused by a translocation of biomass production from below-ground to above-ground parts. At the same time fine-root growth dynamics are strongly affected by the high N supply. Deficiencies of various nutrients (Mg,Ca,K,Mn and Zn) obtained from needle analyses have been reported from different Picea abies stands. In areas with more extensive acidification and nutrient leaching, a decline in tree vitality has been observed. Although deficiency symptoms in forest trees may be reflected in nitrogen/cation ratios in fine roots, few attempts have been made to explain forest damage symptoms from fine-root chemistry. Root damage is often described as a decline in the amount of living fine roots, an increase in the amount of dead versus live fine roots (a lower live/dead ratio) and an increasing amount of dead medium and coarse roots. The primary objectives of the present presentation were to analyse available data on the effects of high nitrogen and sulphur deposition on mineral nutrient balance in tree fine roots and to evaluate the risk of Al interference with cation uptake by roots

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystem

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.A.R.; Heck, I.C.C; Hesen, P.L.G.M.; Leuven, R.S.E.W.; Roelofs, J.G.M.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulphate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulphate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulphate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH 3.8. Under acidified conditions, ammonium sulphate deposition led to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr, the acidification of water appeared to be coupled with changes in alkalinity, sulphate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulphate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 references.

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystems

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.; Heck, I.C.; Hesen, P.L.; Leuven, R.S.; Roelofs, J.G.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulfate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulfate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulfate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH = 3.8. Under acidified conditions, ammonium sulfate deposition lead to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr. The acidification of water appeared to be coupled with changes in alkalinity, sulfate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulfate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 refs.

Polymer deposition morphology by electrospray deposition - Modifications through distance variation

International Nuclear Information System (INIS)

Altmann, K.; Schulze, R.-D.; Friedrich, J.

2014-01-01

Electrospray deposition (ESD) of highly diluted polymers was examined with regard to the deposited surface structure. Only the flight distance (flight time) onto the resulting deposited surface was varied from 20 to 200 mm. An apparatus without any additional heating or gas flows was used. Polyacrylic acid (PAA) and polyallylamine (PAAm) in methanol were deposited on Si wafers. The polymer layers were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, derivatization reactions and Fourier transform infrared spectroscopy using a grazing incidence unit. SEM images illustrated the changing structures of PAA and PAAm. For PAA the deposited structure changed from a smooth film (20 mm) to a film with individual droplets on the coated surface (100 mm and 200 mm), while for PAAm individual droplets can be seen at all distances. The ESD process with cascades of splitting droplets slows down for PAA after distances greater than 40 mm. In contrast, the ESD process for PAAm is nearly stopped within the first flight distance of 20 mm. Residual solvent analysis showed that most of the solvent evaporated within the first 20 mm capillary-sample distance. - Highlights: • We deposited polyacrylic acid and polyallylamine by electrospray ionization (ESI). • The morphology in dependence of flight distance (20 mm to 200 mm) was analyzed. • The amount of residual solvent after deposition was determined. • ESI-process slows down for polyacrylic acid after 40 mm flight distance. • ESI-Process is complete for polyallylamine within the first 20 mm

The effect of pomegranate seed oil and grapeseed oil on cis-9, trans-11 CLA (rumenic acid), n-3 and n-6 fatty acids deposition in selected tissues of chickens.

Science.gov (United States)

Białek, A; Białek, M; Lepionka, T; Kaszperuk, K; Banaszkiewicz, T; Tokarz, A

2018-04-23

The aim of this study was to determine whether diet modification with different doses of grapeseed oil or pomegranate seed oil will improve the nutritive value of poultry meat in terms of n-3 and n-6 fatty acids, as well as rumenic acid (cis-9, trans-11 conjugated linoleic acid) content in tissues diversified in lipid composition and roles in lipid metabolism. To evaluate the influence of applied diet modification comprehensively, two chemometric methods were used. Results of cluster analysis demonstrated that pomegranate seed oil modifies fatty acids profile in the most potent way, mainly by an increase in rumenic acid content. Principal component analysis showed that regardless of type of tissue first principal component is strongly associated with type of deposited fatty acid, while second principal component enables identification of place of deposition-type of tissue. Pomegranate seed oil seems to be a valuable feed additive in chickens' feeding. © 2018 Blackwell Verlag GmbH.

Maternal Docosahexaenoic Acid Increases Adiponectin and Normalizes IUGR-Induced Changes in Rat Adipose Deposition

Directory of Open Access Journals (Sweden)

Heidi N. Bagley

2013-01-01

Full Text Available Intrauterine growth restriction (IUGR predisposes to obesity and adipose dysfunction. We previously demonstrated IUGR-induced increased visceral adipose deposition and dysregulated expression of peroxisome proliferator activated receptor-γ2 (PPARγ2 in male adolescent rats, prior to the onset of obesity. In other studies, activation of PPARγ increases subcutaneous adiponectin expression and normalizes visceral adipose deposition. We hypothesized that maternal supplementation with docosahexaenoic acid (DHA, a PPARγ agonist, would normalize IUGR adipose deposition in association with increased PPARγ, adiponectin, and adiponectin receptor expression in subcutaneous adipose. To test these hypotheses, we used a well-characterized model of uteroplacental-insufficiency-(UPI- induced IUGR in the rat with maternal DHA supplementation. Our primary findings were that maternal DHA supplementation during rat pregnancy and lactation (1 normalizes IUGR-induced changes in adipose deposition and visceral PPARγ expression in male rats and (2 increases serum adiponectin, as well as adipose expression of adiponectin and adiponectin receptors in former IUGR rats. Our novel findings suggest that maternal DHA supplementation may normalize adipose dysfunction and promote adiponectin-induced improvements in metabolic function in IUGR.

Maternal docosahexaenoic acid increases adiponectin and normalizes IUGR-induced changes in rat adipose deposition.

Science.gov (United States)

Bagley, Heidi N; Wang, Yan; Campbell, Michael S; Yu, Xing; Lane, Robert H; Joss-Moore, Lisa A

2013-01-01

Intrauterine growth restriction (IUGR) predisposes to obesity and adipose dysfunction. We previously demonstrated IUGR-induced increased visceral adipose deposition and dysregulated expression of peroxisome proliferator activated receptor- γ 2 (PPAR γ 2) in male adolescent rats, prior to the onset of obesity. In other studies, activation of PPAR γ increases subcutaneous adiponectin expression and normalizes visceral adipose deposition. We hypothesized that maternal supplementation with docosahexaenoic acid (DHA), a PPAR γ agonist, would normalize IUGR adipose deposition in association with increased PPAR γ , adiponectin, and adiponectin receptor expression in subcutaneous adipose. To test these hypotheses, we used a well-characterized model of uteroplacental-insufficiency-(UPI-) induced IUGR in the rat with maternal DHA supplementation. Our primary findings were that maternal DHA supplementation during rat pregnancy and lactation (1) normalizes IUGR-induced changes in adipose deposition and visceral PPAR γ expression in male rats and (2) increases serum adiponectin, as well as adipose expression of adiponectin and adiponectin receptors in former IUGR rats. Our novel findings suggest that maternal DHA supplementation may normalize adipose dysfunction and promote adiponectin-induced improvements in metabolic function in IUGR.

Stability of sputter deposited ZnO:Cr films against acids

International Nuclear Information System (INIS)

Shinoda, Makoto; Nishide, Toshikazu; Sawada, Yutaka; Hosaka, Masato; Matsumoto, Toshihiko.

1993-01-01

ZnO:Cr films were deposited on water-cooled soda-lime glass substrates at room temperature in an Ar atmosphere by rf magnetron sputtering of a ZnO target on which Cr chips were placed. The films exhibited extraordinary stability against acids such as HCl or HNO 3 , and also high resistivities similar to those of ZnO films. The addition of Cr suppressed the growth of ZnO grains which resulted in the formation of a dense film with a smooth surface. The stability and high resistivity displayed by the ZnO:Cr films can be attributed to the formation of a chromium-oxide-rich grain boundary. (author)

Piper sarmentosum is comparable to glycyrrhizic acid in reducing visceral fat deposition in adrenalectomised rats given dexamethasone.

Science.gov (United States)

Fairus, A; Ima Nirwana, S; Elvy Suhana, M R; Tan, M H; Santhana, R; Farihah, H S

2013-01-01

Visceral obesity may be due to the dysregulation of cortisol production or metabolism that lead to metabolic disease. In adipose tissue, the enzyme 11beta-hydroxysteroid dehydrogenase type 1 regulates cortisol metabolism (11beta-HSD1). A previous study showed an increase in the visceral fat deposition in adrenalectomised rats given intramuscular dexamethasone. Glycyrrhizic acid (GCA) has been shown to reduce fat deposition because it is a known potent inhibitor of the 11beta-HSD1 enzyme. Piper sarmentosum (PS) is an edible medicinal plant commonly used in Asia as traditional medicine for treating diabetes, hypertension and joint pains. In this study, we determined the effects of PS extract on the disposition and morphology of perirenal adipocytes of adrenalectomised rats given intramuscular dexamethasone. A total of 21 male Spraque Dawley rats were adrenalectomised and given intramuscular dexamethasone, 120 μg/kg/day. These rats were further divided into three groups: adrenalectomised control (ADR+Dexa; n=7), GCA-treated (ADR+Dexa+GCA; dose=240 mg/kg/day; n=7) and PS-treated (ADR+Dexa+PS; dose=125 mg/kg/day; n=7) groups. The various treatments were given via gastric gavage following 2 weeks of adrenalectomy. Treatment with PS extract for 8 weeks showed decreased deposition of perirenal adipocytes which was similar to the GCA-treated group. However, PS-treated rats had thinner adipocyte membrane compared with that of the GCA-treated group. In conclusion, PS extract decreased perirenal fat deposition and reduced the diameter of the adipocyte membrane. However, the mechanisms of action needed further study.

Control of ordered mesoporous titanium dioxide nanostructures formed using plasma enhanced glancing angle deposition

Energy Technology Data Exchange (ETDEWEB)

Gibson, Des [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Child, David, E-mail: david.child@uws.ac.uk [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Song, Shigeng; Zhao, Chao [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Alajiani, Yahya [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Department of Physics, Faculty of Science, Jazan University, Jazan (Saudi Arabia); Waddell, Ewan [Thin Film Solutions Ltd, West of Scotland Science Park, Glasgow, G20 0TH (United Kingdom)

2015-10-01

Three dimensional nanostructures of mesoporous (pore diameter between 2-50 nm) nanocrystalline titania (TiO{sub 2}) were produced using glancing angle deposition combined with plasma ion assisted deposition, providing plasma enhanced glancing angle deposition eliminating the need for post-annealing to achieve film crystallinity. Electron beam evaporation was chosen to deposit nanostructures at various azimuthal angles, achieving designed variation in three dimensional nanostructure. A thermionic broad beam hollow cathode plasma source was used to enhance electron beam deposition, with ability to vary in real time ion fluxes and energies providing a means to modify and control TiO{sub 2} nanostructure real time with controlled density and porosity along and lateral to film growth direction. Plasma ion assisted deposition was carried out at room temperature using a hollow cathode plasma source, ensuring low heat loading to the substrate during deposition. Plasma enhanced glancing angle TiO{sub 2} structures were deposited onto borosilicate microscope slides and used to characterise the effects of glancing angle and plasma ion energy distribution function on the optical and nanostructural properties. Variation in TiO{sub 2} refractive index from 1.40 to 2.45 (@ 550 nm) using PEGLAD is demonstrated. Results and analysis of the influence of plasma enhanced glancing angle deposition on evaporant path and resultant glancing angle deviation from standard GLAD are described. Control of mesoporous morphology is described, providing a means of optimising light trapping features and film porosity, relevant to applications such as fabrication of dye sensitised solar cells. - Highlights: • Plasma assistance during glancing angle deposition enables control of morphology. • Ion energy variation during glancing angle deposition varies columnar angle • Column thickness of glancing angle deposition dependant on ion current density • Ion current density variation during

Co-Deposition of a Hydrogel/Calcium Phosphate Hybrid Layer on 3D Printed Poly(Lactic Acid Scaffolds via Dip Coating: Towards Automated Biomaterials Fabrication

Directory of Open Access Journals (Sweden)

Matthias Schneider

2018-03-01

Full Text Available The article describes the surface modification of 3D printed poly(lactic acid (PLA scaffolds with calcium phosphate (CP/gelatin and CP/chitosan hybrid coating layers. The presence of gelatin or chitosan significantly enhances CP co-deposition and adhesion of the mineral layer on the PLA scaffolds. The hydrogel/CP coating layers are fairly thick and the mineral is a mixture of brushite, octacalcium phosphate, and hydroxyapatite. Mineral formation is uniform throughout the printed architectures and all steps (printing, hydrogel deposition, and mineralization are in principle amenable to automatization. Overall, the process reported here therefore has a high application potential for the controlled synthesis of biomimetic coatings on polymeric biomaterials.

National Acid Precipitation Assessment Program: 1990 Integrated Assessment report

International Nuclear Information System (INIS)

1991-11-01

The document, the 'Integrated Assessment,' is a summary of the causes and effects of acidic deposition and a comparison of the costs and effectiveness of alternative emission control scenarios. In developing the 'Integrated Assessment,' it was NAPAP's goal to produce a structured compilation of policy-relevant technical information. The Integrated Assessment is based on findings and data from a series of twenty-seven State-of-Science/Technology Reports (SOS/T) on acidic deposition published by NAPAP in 1990. The scope of the documents includes: (1) emissions, atmospheric processes and deposition; (2) effects on surface waters, forests, agricultural crops, exposed materials, human health, and visibility; and (3) control technologies, future emissions, and effects valuation

Gasification of carbon deposits on catalysts and metal surfaces

Energy Technology Data Exchange (ETDEWEB)

Figueiredo, J L

1986-10-01

'Coke' deposited on catalysts and reactor surfaces includes a variety of carbons of different structures and origins, their reactivities being conveniently assessed by Temperature Programmed Reaction (TPR). The gasification of carbon deposits obtained in the laboratory under well controlled conditions, and the regeneration of coked catalysts from petroleum refining processes are reviewed and discussed. Filamentary carbon deposits, containing dispersed metal particles, behave as supported metal catalysts during gasification, and show high reactivities. Pyrolytic and acid catalysis carbons are less reactive on their own, as the gasification is not catalysed; however, metal components of the catalyst or metal impurities deposited on the surface may enhance gasification. 26 refs., 8 figs., 2 tabs.

4.2. The kinetics of nitric acid decomposition of calcined borosilicate raw material of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to kinetics of nitric acid decomposition of calcined borosilicate raw material of Ak-Arkhar Deposit. The dependence of nitric acid decomposition of calcined boric raw material for extraction of boron oxide on temperature (20-100 deg C) and process duration (15-60 minutes) was defined. It was defined that at temperature increasing the extraction rate of boron oxide increases from 20.8 to 78.6%.

Dendrochemical evidence for soil recovery from acidic deposition in forests of the northeastern U.S. with comparisons to the southeastern U.S. and Russia

Science.gov (United States)

Walter C. Shortle; Kevin T. Smith; Andrei G. Lapenis

2017-01-01

A soil resampling approach has detected an early stage of recovery in the cation chemistry of spruce forest soil due to reductions in acid deposition. That approach is limited by the lack of soil data and archived soil samples prior to major increases in acid deposition during the latter half of the 20th century. An alternative approach is the dendrochemical analysis...

All-gas-phase synthesis of UiO-66 through modulated atomic layer deposition

Science.gov (United States)

Lausund, Kristian Blindheim; Nilsen, Ola

2016-11-01

Thin films of stable metal-organic frameworks (MOFs) such as UiO-66 have enormous application potential, for instance in microelectronics. However, all-gas-phase deposition techniques are currently not available for such MOFs. We here report on thin-film deposition of the thermally and chemically stable UiO-66 in an all-gas-phase process by the aid of atomic layer deposition (ALD). Sequential reactions of ZrCl4 and 1,4-benzenedicarboxylic acid produce amorphous organic-inorganic hybrid films that are subsequently crystallized to the UiO-66 structure by treatment in acetic acid vapour. We also introduce a new approach to control the stoichiometry between metal clusters and organic linkers by modulation of the ALD growth with additional acetic acid pulses. An all-gas-phase synthesis technique for UiO-66 could enable implementations in microelectronics that are not compatible with solvothermal synthesis. Since this technique is ALD-based, it could also give enhanced thickness control and the possibility to coat irregular substrates with high aspect ratios.

Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells

Energy Technology Data Exchange (ETDEWEB)

Tavakoli, M.M. [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Simchi, A., E-mail: simchi@sharif.edu [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Institute for Nanoscience and Nanotechnology, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of); Aashuri, H. [Department of Materials Science and Engineering, Sharif University of Technology, 14588 Tehran (Iran, Islamic Republic of)

2015-04-15

Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction, absorption and dynamic light scattering showed that the nanocrystals processed at the supercritical condition (330 °C) are fully crystalline with a narrow size distribution of ∼3 nm with an absorption wavelength of 915 nm (bandgap of 1.3 eV). Fourier transform infrared spectroscopy indicated that the PbS quantum dots are passivated by oleic acid molecules during the growth. Photovoltaic characteristics of Schottky junction solar cells showed an improvement over devices prepared by spin-coating. - Highlights: • Supercritical fluid processing and in situ deposition of PbS QDs are presented. • The prepared nanocrystals are mono-dispersed with an optical bandgap of 1.3 eV. • Photovoltaic performance of the in situ deposited nanocrystals is reported. • An improved PV performance compared to spin coated Schottky solar cells is shown.

Metallization on FDM Parts Using the Chemical Deposition Technique

Directory of Open Access Journals (Sweden)

Azhar Equbal

2014-08-01

Full Text Available Metallization of ABS (acrylonitrile-butadiene-styrene parts has been studied on flat part surfaces. These parts are fabricated on an FDM (fused deposition modeling machine using the layer-wise deposition principle using ABS as a part material. Electroless copper deposition on ABS parts was performed using two different surface preparation processes, namely ABS parts prepared using chromic acid for etching and ABS parts prepared using a solution mixture of sulphuric acid and hydrogen peroxide (H2SO4/H2O2 for etching. After surface preparations using these routes, copper (Cu is deposited electrolessly using four different acidic baths. The acidic baths used are 5 wt% CuSO4 (copper sulfate with 15 wt% of individual acids, namely HF (hydrofluoric acid, H2SO4 (sulphuric acid, H3PO4 (phosphoric acid and CH3COOH (acetic acid. Cu deposition under different acidic baths used for both the routes is presented and compared based on their electrical performance, scanning electron microscopy (SEM and energy dispersive X-ray spectrometry (EDS. The result shows that chromic acid etched samples show better electrical performance and Cu deposition in comparison to samples etched via H2SO4/H2O2.

Correlation of film density and wet etch rate in hydrofluoric acid of plasma enhanced atomic layer deposited silicon nitride

Energy Technology Data Exchange (ETDEWEB)

Provine, J., E-mail: jprovine@stanford.edu; Schindler, Peter; Kim, Yongmin; Walch, Steve P.; Kim, Hyo Jin [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Kim, Ki-Hyun [Manufacturing Technology Center, Samsung Electronics, Suwon, Gyeonggi-Do (Korea, Republic of); Prinz, Fritz B. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States)

2016-06-15

The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposition (ALD) of silicon nitride (SiN{sub x}), particularly for use a low k dielectric spacer. One of the key material properties needed for SiN{sub x} films is a low wet etch rate (WER) in hydrofluoric (HF) acid. In this work, we report on the evaluation of multiple precursors for plasma enhanced atomic layer deposition (PEALD) of SiN{sub x} and evaluate the film’s WER in 100:1 dilutions of HF in H{sub 2}O. The remote plasma capability available in PEALD, enabled controlling the density of the SiN{sub x} film. Namely, prolonged plasma exposure made films denser which corresponded to lower WER in a systematic fashion. We determined that there is a strong correlation between WER and the density of the film that extends across multiple precursors, PEALD reactors, and a variety of process conditions. Limiting all steps in the deposition to a maximum temperature of 350 °C, it was shown to be possible to achieve a WER in PEALD SiN{sub x} of 6.1 Å/min, which is similar to WER of SiN{sub x} from LPCVD reactions at 850 °C.

Responses of soil N-fixing bacteria communities to invasive plant species under different types of simulated acid deposition

Science.gov (United States)

Wang, Congyan; Zhou, Jiawei; Jiang, Kun; Liu, Jun; Du, Daolin

2017-06-01

Biological invasions have incurred serious threats to native ecosystems in China, and soil N-fixing bacteria communities (SNB) may play a vital role in the successful plant invasion. Meanwhile, anthropogenic acid deposition is increasing in China, which may modify or upgrade the effects that invasive plant species can cause on SNB. We analyzed the structure and diversity of SNB by means of new generation sequencing technology in soils with different simulated acid deposition (SAD), i.e., different SO4 2- to NO3 - ratios, and where the invasive ( Amaranthus retroflexus L.) and the native species ( Amaranthus tricolor L.) grew mixed or isolated for 3 months. A. retroflexus itself did not exert significant effects on the diversity and richness of SNB but did it under certain SO4 2- to NO3 - ratios. Compared to soils where the native species grew isolated, the soils where the invasive A. retroflexus grew isolated showed lower relative abundance of some SNB classes under certain SAD treatments. Some types of SAD can alter soil nutrient content which in turn could affect SNB diversity and abundance. Specifically, greater SO4 2- to NO3 - ratios tended to have more toxic effects on SNB likely due to the higher exchange capacity of hydroxyl groups (OH-) between SO4 2- and NO3 -. As a conclusion, it can be expected a change in the structure of SNB after A. retroflexus invasion under acid deposition rich in sulfuric acid. This change may create a plant soil feedback favoring future A. retroflexus invasions.

Target loads of atmospheric sulfur deposition for the protection and recovery of acid-sensitive streams in the Southern Blue Ridge Province.

Science.gov (United States)

Sullivan, Timothy J; Cosby, Bernard J; Jackson, William A

2011-11-01

An important tool in the evaluation of acidification damage to aquatic and terrestrial ecosystems is the critical load (CL), which represents the steady-state level of acidic deposition below which ecological damage would not be expected to occur, according to current scientific understanding. A deposition load intended to be protective of a specified resource condition at a particular point in time is generally called a target load (TL). The CL or TL for protection of aquatic biota is generally based on maintaining surface water acid neutralizing capacity (ANC) at an acceptable level. This study included calibration and application of the watershed model MAGIC (Model of Acidification of Groundwater in Catchments) to estimate the target sulfur (S) deposition load for the protection of aquatic resources at several future points in time in 66 generally acid-sensitive watersheds in the southern Blue Ridge province of North Carolina and two adjoining states. Potential future change in nitrogen leaching is not considered. Estimated TLs for S deposition ranged from zero (ecological objective not attainable by the specified point in time) to values many times greater than current S deposition depending on the selected site, ANC endpoint, and evaluation year. For some sites, one or more of the selected target ANC critical levels (0, 20, 50, 100μeq/L) could not be achieved by the year 2100 even if S deposition was reduced to zero and maintained at that level throughout the simulation. Many of these highly sensitive streams were simulated by the model to have had preindustrial ANC below some of these target values. For other sites, the watershed soils contained sufficiently large buffering capacity that even very high sustained levels of atmospheric S deposition would not reduce stream ANC below common damage thresholds. Copyright © 2011 Elsevier Ltd. All rights reserved.

Nitrogen deposition and grass encroachment in calcareous and acidic Grey dunes (H2130) in NW-Europe

NARCIS (Netherlands)

Kooijman, A.M.; van Til, M.; Noordijk, E.; Remke, E.; Kalbitz, K.

We present an overview of high nitrogen deposition effects on coastal dune grasslands in NW-Europe (H2130), especially concerning grass encroachment in calcareous and acidic Grey Dunes. The problem is larger than previously assumed, because critical loads are still too high, and extra N-input from

Urban wet deposition nitrate: a comparison to non-urban deposition

International Nuclear Information System (INIS)

Schultz, J.A.M.

1994-01-01

The concentration of nitrate in both wet and dry deposition has both increased historically and currently, and recently parallels emissions in NO x . Since NO x is produced in amounts comparable to SO 2 , it is an important contributor to acid deposition, and is produced in higher amounts in urban areas due to concentrated sources. Prior to to this study, national acid deposition monitoring networks in the United States have been and remain established in non-urban areas. This research study consisted of a comparison of precipitation sampling and analysis of wet deposition nitrate and pH for each deposition event in each of two urban sites over a 15 mo period. Also, a comparison of urban data and data generated at a nearby non-urban NADP site was made by examination of both monthly and seasonal data. This research suggests that national monitoring programs should consider inclusion of urban and non-urban monitoring sites in order to achieve a more representative regional assessment. 24 refs., 2 figs., 2 tabs

Magmatic-vapor expansion and the formation of high-sulfidation gold deposits: Chemical controls on alteration and mineralization

Science.gov (United States)

Henley, R.W.; Berger, B.R.

2011-01-01

Large bulk-tonnage high-sulfidation gold deposits, such as Yanacocha, Peru, are the surface expression of structurally-controlled lode gold deposits, such as El Indio, Chile. Both formed in active andesite-dacite volcanic terranes. Fluid inclusion, stable isotope and geologic data show that lode deposits formed within 1500. m of the paleo-surface as a consequence of the expansion of low-salinity, low-density magmatic vapor with very limited, if any, groundwater mixing. They are characterized by an initial 'Sulfate' Stage of advanced argillic wallrock alteration ?? alunite commonly with intense silicification followed by a 'Sulfide' Stage - a succession of discrete sulfide-sulfosalt veins that may be ore grade in gold and silver. Fluid inclusions in quartz formed during wallrock alteration have homogenization temperatures between 100 and over 500 ??C and preserve a record of a vapor-rich environment. Recent data for El Indio and similar deposits show that at the commencement of the Sulfide Stage, 'condensation' of Cu-As-S sulfosalt melts with trace concentrations of Sb, Te, Bi, Ag and Au occurred at > 600 ??C following pyrite deposition. Euhedral quartz crystals were simultaneously deposited from the vapor phase during crystallization of the vapor-saturated melt occurs to Fe-tennantite with progressive non-equilibrium fractionation of heavy metals between melt-vapor and solid. Vugs containing a range of sulfides, sulfosalts and gold record the changing composition of the vapor. Published fluid inclusion and mineralogical data are reviewed in the context of geological relationships to establish boundary conditions through which to trace the expansion of magmatic vapor from source to surface and consequent alteration and mineralization. Initially heat loss from the vapor is high resulting in the formation of acid condensate permeating through the wallrock. This Sulfate Stage alteration effectively isolates the expansion of magmatic vapor in subsurface fracture arrays

Characterization of heavy metal desorption from road-deposited sediment under acid rain scenarios.

Science.gov (United States)

Zhao, Bo; Liu, An; Wu, Guangxue; Li, Dunzhu; Guan, Yuntao

2017-01-01

Road-deposited sediments (RDS) on urban impervious surfaces are important carriers of heavy metals. Dissolved heavy metals that come from RDS influenced by acid rain, are more harmful to urban receiving water than particulate parts. RDS and its associated heavy metals were investigated at typical functional areas, including industrial, commercial and residential sites, in Guangdong, Southern China, which was an acid rain sensitive area. Total and dissolved heavy metals in five particle size fractions were analyzed using a shaking method under acid rain scenarios. Investigated heavy metals showed no difference in the proportion of dissolved fraction in the solution under different acid rain pHs above 3.0, regardless of land use. Dissolved loading of heavy metals related to organic carbon content were different in runoff from main traffic roads of three land use types. Coarse particles (>150μm) that could be efficiently removed by conventional street sweepers, accounted for 55.1%-47.1% of the total dissolved metal loading in runoff with pH3.0-5.6. The obtained findings provided a significant scientific basis to understand heavy metal release and influence of RDS grain-size distribution and land use in dissolved heavy metal pollution affected by acid rain. Copyright © 2016. Published by Elsevier B.V.

Influence of hydrofluoric acid treatment on electroless deposition of Au clusters

Directory of Open Access Journals (Sweden)

Rachela G. Milazzo

2017-01-01

Full Text Available The morphology of gold nanoparticles (AuNPs deposited on a (100 silicon wafer by simple immersion in a solution containing a metal salt and hydrofluoric acid (HF is altered by HF treatment both before and after deposition. The gold clusters are characterized by the presence of flat regions and quasispherical particles consistent with the layer-by-layer or island growth modes, respectively. The cleaning procedure, including HF immersion prior to deposition, affects the predominantly occurring gold structures. Flat regions, which are of a few tens of nanometers long, are present after immersion for 10 s. The three-dimensional (3D clusters are formed after a cleaning procedure of 4 min, which results in a large amount of spherical particles with a diameter of ≈15 nm and in a small percentage of residual square layers of a few nanometers in length. The samples were also treated with HF after the deposition and we found out a general thickening of flat regions, as revealed by TEM and AFM analysis. This result is in contrast to the coalescence observed in similar experiments performed with Ag. It is suggested that the HF dissolves the silicon oxide layer formed on top of the thin flat clusters and promotes the partial atomic rearrangement of the layered gold atoms, driven by a reduction of the surface energy. The X-ray diffraction investigation indicated changes in the crystalline orientation of the flat regions, which partially lose their initially heteroepitaxial relationship with the substrate. A postdeposition HF treatment for almost 70 s has nearly the same effect of long duration, high temperature annealing. The process presented herein could be beneficial to change the spectral response of nanoparticle arrays and to improve the conversion efficiency of hybrid photovoltaic devices.

Effects of multiple stresses hydropower, acid deposition and climate change on water chemistry and salmon populations in the River Otra, Norway.

Science.gov (United States)

Wright, Richard F; Couture, Raoul-Marie; Christiansen, Anne B; Guerrero, José-Luis; Kaste, Øyvind; Barlaup, Bjørn T

2017-01-01

Many surface waters in Europe suffer from the adverse effects of multiple stresses. The Otra River, southernmost Norway, is impacted by acid deposition, hydropower development and increasingly by climate change. The river holds a unique population of land-locked salmon and anadromous salmon in the lower reaches. Both populations have been severely affected by acidification. The decrease in acid deposition since the 1980s has led to partial recovery of both populations. Climate change with higher temperatures and altered precipitation can potentially further impact fish populations. We used a linked set of process-oriented models to simulate future climate, discharge, and water chemistry at five sub-catchments in the Otra river basin. Projections to year 2100 indicate that future climate change will give a small but measureable improvement in water quality, but that additional reductions in acid deposition are needed to promote full restoration of the fish communities. These results can help guide management decisions to sustain key salmon habitats and carry out effective long-term mitigation strategies such as liming. The Otra River is typical of many rivers in Europe in that it fails to achieve the good ecological status target of the EU Water Framework Directive. The programme of measures needed in the river basin management plan necessarily must consider the multiple stressors of acid deposition, hydropower, and climate change. This is difficult, however, as the synergistic and antagonistic effects are complex and challenging to address with modelling tools currently available. Copyright © 2016 Elsevier B.V. All rights reserved.

Controllable deposition distance of aligned pattern via dual-nozzle near-field electrospinning

Science.gov (United States)

Wang, Zhifeng; Chen, Xindu; Zeng, Jun; Liang, Feng; Wu, Peixuan; Wang, Han

2017-03-01

For large area micro/nano pattern printing, multi-nozzle electrohydrodynamic (EHD) printing setup is an efficient method to boost productivity in near-field electrospinning (NFES) process. And controlling EHD multi-jet accurate deposition under the interaction of nozzles and other parameters are crucial concerns during the process. The influence and sensitivity of various parameters such as the needle length, needle spacing, electrode-to-collector distance, voltage etc. on the direct-write patterning performance was investigated by orthogonal experiments with dual-nozzle NFES setup, and then the deposition distance estimated based on a novel model was compared with measurement results and proven. More controllable deposition distance and much denser of aligned naofiber can be achieved by rotating the dual-nozzle setup. This study can be greatly contributed to estimate the deposition distance and helpful to guide the multi-nozzle NFES process to accurate direct-write pattern in manufacturing process in future.

Controlled Deposition of Tin Oxide and Silver Nanoparticles Using Microcontact Printing

Directory of Open Access Journals (Sweden)

Joo C. Chan

2015-02-01

Full Text Available This report describes extensive studies of deposition processes involving tin oxide (SnOx nanoparticles on smooth glass surfaces. We demonstrate the use of smooth films of these nanoparticles as a platform for spatially-selective electroless deposition of silver by soft lithographic stamping. The edge and height roughness of the depositing metallic films are 100 nm and 20 nm, respectively, controlled by the intrinsic size of the nanoparticles. Mixtures of alcohols as capping agents provide further control over the size and shape of nanoparticles clusters. The distribution of cluster heights obtained by atomic force microscopy (AFM is modeled through a modified heterogeneous nucleation theory as well as Oswald ripening. The thermodynamic modeling of the wetting properties of nanoparticles aggregates provides insight into their mechanism of formation and how their properties might be further exploited in wide-ranging applications.

Model boiler studies on deposition and corrosion

International Nuclear Information System (INIS)

Balakrishnan, P.V.; McVey, E.G.

1977-09-01

Deposit formation was studied in a model boiler, with sea-water injections to simulate the in-leakage which could occur from sea-water cooled condensers. When All Volatile Treatment (AVT) was used for chemistry control the deposits consisted of the sea-water salts and corrosion products. With sodium phosphate added to the boiler water, the deposits also contained the phosphates derived from the sea-water salts. The deposits were formed in layers of differing compositions. There was no significant corrosion of the Fe-Ni-Cr alloy boiler tube under deposits, either on the open area of the tube or in crevices. However, carbon steel that formed a crevice around the tube was corroded severely when the boiler water did not contain phosphate. The observed corrosion of carbon steel was caused by the presence of acidic, highly concentrated chloride solution produced from the sea-water within the crevice. Results of theoretical calculations of the composition of the concentrated solution are presented. (author)

Boosting the performance of Pt electro-catalysts toward formic acid electro-oxidation by depositing sub-monolayer Au clusters

International Nuclear Information System (INIS)

Bi Xuanxuan; Wang Rongyue; Ding Yi

2011-01-01

Highlights: → Au decoration on Pt nanoparticles simultaneously increases the activity and stability. → Sub-monolayer Au decoration changes the reaction path and results in the activity improvement. → Increasing the Au coverage will increase the specific activity. → Proper Au coverage results in a maximum mass specific activity. - Abstract: CO poisoning is the main obstacle to the application of Pt nanoparticles as anode catalysts in direct formic acid fuel cells (DFAFCs). Significant types of Pt alloys have been investigated, which often demonstrate evidently improved catalytic performance governed by difference mechanisms. By using a well-known electrochemical technique of under potential deposition and in situ redox replacement, sub-monolayer Au clusters are deposited onto Pt nanoparticle surfaces in a highly controlled manner, generating a unique surface alloy structure. Under optimum conditions, the modified Pt nanoparticles can exhibit greatly enhanced specific activity (up to 23-fold increase) at potential of -0.2 V vs. MSE toward formic acid electro-oxidation (FAEO). Interestingly, the mass specific activity can also be improved by a factor of 2.3 at potential of -0.35 V vs. MSE although significant amount of surface Pt atoms are covered by the overlayer Au clusters. The much enhanced catalytic activity can be ascribed to a Pt surface ensemble effect, which induces change of the reaction path. Moreover, the sub-monolayer Au coating on the surface also contributes to the enhanced catalyst durability by inhibiting the Pt oxidation. These results show great potential to rationally design more active and stable nanocatalysts by modifying the Pt surface with otherwise inactive materials.

Target loads of atmospheric sulfur deposition for the protection and recovery of acid-sensitive streams in the Southern Blue Ridge Province

Science.gov (United States)

Timothy Sullivan; Bernard Cosby; William Jackson

2011-01-01

An important tool in the evaluation of acidification damage to aquatic and terrestrial ecosystems is the critical load (CL), which represents the steady-state level of acidic deposition below which ecological damage would not be expected to occur, according to current scientific understanding. A deposition load intended to be protective of a specified resource...

The distribution of common construction materials at risk to acid deposition in the United States

Science.gov (United States)

Lipfert, Frederick W.; Daum, Mary L.

Information on the geographic distribution of various types of exposed materials is required to estimate the economic costs of damage to construction materials from acid deposition. This paper focuses on the identification, evaluation and interpretation of data describing the distributions of exterior construction materials, primarily in the United States. This information could provide guidance on how data needed for future economic assessments might be acquired in the most cost-effective ways. Materials distribution surveys from 16 cities in the U.S. and Canada and five related databases from government agencies and trade organizations were examined. Data on residential buildings are more commonly available than on nonresidential buildings; little geographically resolved information on distributions of materials in infrastructure was found. Survey results generally agree with the appropriate ancillary databases, but the usefulness of the databases is often limited by their coarse spatial resolution. Information on those materials which are most sensitive to acid deposition is especially scarce. Since a comprehensive error analysis has never been performed on the data required for an economic assessment, it is not possible to specify the corresponding detailed requirements for data on the distributions of materials.

Ester Sensing with Poly (Aniline-co-m-aminobenzoic Acid Deposited on Poly (Vinyl Alcohol

Directory of Open Access Journals (Sweden)

S. ADHIKARI

2011-02-01

Full Text Available Poly (aniline-co-m-aminobenzoic acid was deposited on poly (vinyl alcohol film by in situ oxidative polymerization of the monomers aniline and m-aminobenzoic acid. Sensing experiments were performed on the composite film with the injection of various concentrations of hexenyl acetate and hexenyl butyrate at room temperature. The sensor responded rapidly and reversibly in the presence of hexenyl acetate and hexenyl butyrate vapors which was detected by resistance change of the composite film upon exposure to the vapor. Selectivity tests revealed that the sensor selectively responded to hexenyl butyrate compared to hexenyl acetate. The sensing response has been explained on the basis of FT-IR spectroscopic analysis of the polymer film before and after exposure to the ester vapor.

Real-time beam tracing for control of the deposition location of electron cyclotron waves

Energy Technology Data Exchange (ETDEWEB)

Reich, M., E-mail: matthias.reich@ipp.mpg.de; Bilato, R.; Mszanowski, U.; Poli, E.; Rapson, C.; Stober, J.; Volpe, F.; Zille, R.

2015-11-15

Highlights: • We successfully integrated a real-time EC beam tracing code at ASDEX Upgrade. • The calculation of EC beam deposition location is fast enough for control purposes. • The accuracy of the deposition location calculation exceeds equivalent measurements. • The implementation method is by design portable to larger fusion devices. - Abstract: Plasma control techniques that use electron cyclotron (EC) resonance heating and current drive such as control of neoclassical tearing modes require accurate control of the deposition location of EC beams. ASDEX Upgrade has successfully implemented a real-time version of the beam-tracing code TORBEAM into its real-time diagnostic system to act as a globally available module that calculates current deposition location and its sensitivity from other real-time diagnostic measurements for all its moveable EC wave launchers. Based on a highly (100×) accelerated version of TORBEAM, the software implementation as a diagnostic process uses parallelization and achieves cycle times of 15–20 ms for determining the radial deposition location of 12 beams in the plasma. This cycle time includes data input–output overhead arising from the use of available real-time signals. The system is by design portable to other machines such as ITER.

Controllable nitrogen doping in as deposited TiO{sub 2} film and its effect on post deposition annealing

Energy Technology Data Exchange (ETDEWEB)

Deng, Shaoren; Devloo-Casier, Kilian; Devulder, Wouter; Dendooven, Jolien; Deduytsche, Davy; Detavernier, Christophe, E-mail: Christophe.Detavernier@ugent.be [Department of Solid State Sciences, Ghent University, Krijgslaan 281/S1, B-9000 Gent (Belgium); Verbruggen, Sammy W. [Department of Bio-Engineering Sciences, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium and Center for Surface Chemistry and Catalysis, KU Leuven, Kasteelpark Arenberg 23, B-3001 Heverlee (Belgium); Lenaerts, Silvia [Department of Bio-Engineering Sciences, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Martens, Johan A. [Center for Surface Chemistry and Catalysis, KU Leuven, Kasteelpark Arenberg 23, B-3001 Heverlee (Belgium); Van den Berghe, Sven [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)

2014-01-15

In order to narrow the band gap of TiO{sub 2}, nitrogen doping by combining thermal atomic layer deposition (TALD) of TiO{sub 2} and plasma enhanced atomic layer deposition (PEALD) of TiN has been implemented. By altering the ratio between TALD TiO{sub 2} and PEALD TiN, the as synthesized TiO{sub x}N{sub y} films showed different band gaps (from 1.91 eV to 3.14 eV). In situ x-ray diffraction characterization showed that the crystallization behavior of these films changed after nitrogen doping. After annealing in helium, nitrogen doped TiO{sub 2} films crystallized into rutile phase while for the samples annealed in air a preferential growth of the anatase TiO{sub 2} along (001) orientation was observed. Photocatalytic tests of the degradation of stearic acid were done to evaluate the effect of N doping on the photocatalytic activity.

Aeration-Controlled Formation of Acid in Heterolactic Fermentations

DEFF Research Database (Denmark)

Adler-Nissen, Jens

1994-01-01

fermentation processes should be analyzed as fed-batch fermentations with oxygen as the limiting substrate. Addition of fructose in limited amounts leads to the formation of one half mole of acetic acid for each mole fructose, thus offering an alternative mechanism for controlling acetic acid formation.......Controlled aeration of Leuconostoc mesenteroides was studied as a possible mechanism for control of the formation of acetic acid, a metabolite of major influence on the taste of lactic fermented foods. Fermentations were carried out in small scale in a medium in which growth was limited...... by the buffer capacity only. Ethanol and acetic acid formed during the fermentation were analyzed by rapid head space gas chromatography, and the ratio of the molar concentrations of these two volatiles quantitatively predicted the balance between the formation of acetic acid and lactic acid. The oxygen...

Impact of the Fused Deposition (FDM) Printing Process on Polylactic Acid (PLA) Chemistry and Structure

OpenAIRE

Michael Arthur Cuiffo; Jeffrey Snyder; Alicia M. Elliott; Nicholas Romero; Sandhiya Kannan; Gary P. Halada

2017-01-01

Polylactic acid (PLA) is an organic polymer commonly used in fused deposition (FDM) printing and biomedical scaffolding that is biocompatible and immunologically inert. However, variations in source material quality and chemistry make it necessary to characterize the filament and determine potential changes in chemistry occurring as a result of the FDM process. We used several spectroscopic techniques, including laser confocal microscopy, Fourier transform infrared (FTIR) spectroscopy and pho...

The impact of acid deposition and forest harvesting on lakes and their forested catchments in south central Ontario: a critical loads approach

Directory of Open Access Journals (Sweden)

S. A. Watmough

2002-01-01

Full Text Available The impact of acid deposition and tree harvesting on three lakes and their representative sub-catchments in the Muskoka-Haliburton region of south-central Ontario was assessed using a critical loads approach. As nitrogen dynamics in forest soils are complex and poorly understood, for simplicity and to allow comparison among lakes and their catchments, CLs (A for both lakes and forest soils were calculated assuming that nitrate leaching from catchments will not change over time (i.e. a best case scenario. In addition, because soils in the region are shallow, base cation weathering rates for the representative sub-catchments were calculated for the entire soil profile and these estimates were also used to calculate critical loads for the lakes. These results were compared with critical loads obtained by the Steady State Water Chemistry (SSWC model. Using the SSWC model, critical loads for lakes were between 7 and 19 meq m-2yr-1 higher than those obtained from soil measurements. Lakes and forests are much more sensitive to acid deposition if forests are harvested, but two acid-sensitive lakes had much lower critical loads than their respective forested sub-catchments implying that acceptable acid deposition levels should be dictated by the most acid-sensitive lakes in the region. Under conditions that assume harvesting, the CL (A is exceeded at two of the three lakes and five of the six sub-catchments assessed in this study. However, sulphate export from catchments greatly exceeds input in bulk deposition and, to prevent lakes from falling below the critical chemical limit, sulphate inputs to lakes must be reduced by between 37% and 92% if forests are harvested. Similarly, sulphate leaching from forested catchments that are harvested must be reduced by between 16 and 79% to prevent the ANC of water draining the rooting zone from falling below 0 μeq l-1. These calculations assume that extremely low calcium leaching losses (9–27 μeq l-1 from

Optimization of spray deposition and Tetranychus urticae control with air assisted and electrostatic sprayer

Directory of Open Access Journals (Sweden)

Denise Tourino Rezende de Cerqueira

Full Text Available ABSTRACT: Improved spray deposition can be attained by electrostatically charging spray droplets, which increases the attraction of droplets to plants and decreases operator exposure to pesticide and losses to the environment. However, this technique alone is not sufficient to achieve desirable penetration of the spray solution into the crop canopy; thus, air assistance can be added to the electrostatic spraying to further improve spray deposition. This study was conducted to compare different spraying technologies on spray deposition and two-spotted spider mite control in cut chrysanthemum. Treatments included in the study were: conventional TJ 8003 double flat fan nozzles, conventional TXVK-3 hollow cone nozzles, semi-stationary motorized jet launched spray with electrostatic spray system (ESS and air assistance (AA, and semi-stationary motorized jet launched spray with AA only (no ESS. To evaluate the effect of these spraying technologies on the control of two-spotted spider mite, a control treatment was included that did not receive an acaricide application. The AA spraying technology, with or without ESS, optimized spray deposition and provided satisfactory two-spotted spider mite control up to 4 days after application.

Stream chemistry in the eastern United States. 2. Current sources of acidity in acidic and low acid-neutralizing-capacity streams

International Nuclear Information System (INIS)

Herlihy, A.T.; Kaufmann, P.R.; Mitch, M.E.

1991-01-01

The authors examined anion composition in National Stream Survey (NSS) data in order to evaluate the most probable sources of current acidity in acidic and low acid neutralizing capacity (ANC) streams in the eastern United States. Acidic streams that had almost no organic influence (less than 10% of total anions) and sulfate and nitrate concentrations indicative of evaporative concentration of atmospheric deposition were classified as acidic due to acidic deposition. These acidic streams were located in small forested watersheds in the Mid-Atlantic Highlands (an estimated 1950 km of stream length) and in the Mid-Atlantic Coastal Plain (1250 km). Acidic streams affected primarily by acidic deposition but also influenced by naturally occurring organic anions accounted for another 1180 km of acidic stream length and were located in the New Jersey Pine Barrens, plateau tops in the Mid-Atlantic and Southeast Highlands, and the Florida Panhandle. The total length of streams acidic due to acid mine drainage in the NSS (4590 km) was about the same as the total length of acidic streams likely affected by acidic deposition (4380 km). Acidic streams whose acid anion composition was dominated by organics were located in Florida and the Mid-Atlantic Coastal Plain. In Florida, most of the acidic streams were organic dominated, whereas about half of the streams in the Mid-Atlantic Coastal Plain were organic dominated. Organic-dominated acidic streams were not observed in the Mid-Atlantic and Southeast Highlands

Deposition of aqueous aerosol of technetium-99m diethylene triamine penta-acetic acid generated and delivered by a novel system (AERx) in healthy subjects

International Nuclear Information System (INIS)

Chan, H.K.; Eberl, S.; Bautovich, G.

1999-01-01

Deposition of technetium-99m diethylene triamine penta-acetic acid aqueous radioaerosols generated by a novel aerosol delivery system (AER x ) was studied in six healthy subjects using both planar and single-photon emission tomography (SPET) imaging. AER x is a microprocessor-controlled, bolus inhalation device that is actuated at pre-programmed values of inspiratory flow rate and volume. The aims of the study were to determine the effects of posture and inhaled volume upon deposition of the aerosol in the lungs. Each subject inhaled the radioaerosol in two positions (supine vs sitting) and with two inspiratory manoeuvres [vital capacity (VC) vs ''fixed volume'' of 1 l above functional residual capacity]. Simultaneous transmission-emission planar and tomographic images were acquired. The results showed diffuse deposition of the aerosol in the lung. Neither the breathing manoeuvre nor the posture was found to affect the distribution of the aerosol as measured by the ratio of the activity (counts per pixel) in the peripheral:central (penetration index, PI) or in the apex:base regions of the planar lung images (P>0.1). A small, albeit statistically significant, difference in PI (P x system showed high efficiency of delivery, with approximately 50% of the extruded dose in the device depositing in the lung. The uniformity of radioactivity distributed throughout the lung is attributed to the fine particle size (mass median aerodynamic diameter of 2 μm) of the aerosol and the electronic control of aerosol inhalation by the device. In conclusion, the AER x system can be ideal for diffuse aerosol deposition of therapeutic or diagnostic agents and is largely unaffected by inhaled volume and posture. The efficiency of the device device can limit the total radiation exposure of patients and staff administering the radioaerosols, and can make it suitable for delivery of expensive drugs. (orig.)

Deposition of elemental sulfur in city gate Pressure Control Valves (PCVs)

Energy Technology Data Exchange (ETDEWEB)

Quinto, Thiago C. do; Veiga, Leandro S. da; Silva, Marcos J.M. da; Lemos, Marcelo C. de; Goncalves, Luciane T. [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil)

2009-12-19

Deposition of elemental sulfur has been observed in city gate pressure control valves (PCV s), a phenomenon that causes operational problems in these facilities. This article discusses the problems caused by this deposition, especially in pilots of pressure control valves. While passing through PCV s, the flow of natural gas is subjected to a sharp drop in temperature due to the reduction of pressure (Joule-Thompson). When this happens, the elemental sulfur that is in balance with the flow of natural gas is deposited inside the PCV s and the obstacles ahead. Since PCV s are self-operated and use natural gas as the working fluid, the elemental sulfur is also deposited in the pilots as well. Elemental sulfur in powder form has very small particles - around 20 {mu}m - that prevent the perfect operation of the small moving parts of pilots. Because of this, the affected pilot cannot operate the PCV satisfactorily to regulate the pressure of the natural gas supplied to the customer. There are two possible consequences of this situation: when the customer increases consumption, the pressure will decline to less than below the limit established under the supply contract, which can lead to fines; and the pressure can rise above the limit tolerated by pipes, which can lead to dangerous ruptures. (author)

Effects of Acidic Deposition and Soil Acidification on Sugar Maple Trees in the Adirondack Mountains, New York

Science.gov (United States)

T. J. Sullivan; G. B. Lawrence; S. W. Bailey; T. C. McDonnell; C. M. Beier; K. C. Weathers; G. T. McPherson; D. A. Bishop

2013-01-01

We documented the effects of acidic atmospheric deposition and soil acidification on the canopy health, basal area increment, and regeneration of sugar maple (SM) trees across the Adirondack region of New York State, in the northeastern United States, where SM are plentiful but not well studied and where widespread depletion of soil calcium (Ca) has been...

Evidence for fat, oil, and grease (FOG) deposit formation mechanisms in sewer lines.

Science.gov (United States)

He, Xia; Iasmin, Mahbuba; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J; de los Reyes, Francis L

2011-05-15

The presence of hardened and insoluble fats, oil, and grease (FOG) deposits in sewer lines is a major cause of line blockages leading to sanitary sewer overflows (SSOs). Despite the central role that FOG deposits play in SSOs, little is known about the mechanisms of FOG deposit formation in sanitary sewers. In this study, FOG deposits were formed under laboratory conditions from the reaction between free fatty acids and calcium chloride. The calcium and fatty acid profile analysis showed that the laboratory-produced FOG deposit displayed similar characteristics to FOG deposits collected from sanitary sewer lines. Results of FTIR analysis showed that the FOG deposits are metallic salts of fatty acid as revealed by comparisons with FOG deposits collected from sewer lines and pure calcium soaps. Based on the data, we propose that the formation of FOG deposits occurs from the aggregation of excess calcium compressing the double layer of free fatty acid micelles and a saponification reaction between aggregated calcium and free fatty acids.

Enriching acid rock drainage related microbial communities from surface-deposited oil sands tailings.

Science.gov (United States)

Dean, Courtney; Xiao, Yeyuan; Roberts, Deborah J

2016-10-01

Little is known about the microbial communities native to surface-deposited pyritic oil sands tailings, an environment where acid rock drainage (ARD) could occur. The goal of this study was to enrich sulfur-oxidizing organisms from these tailings and determine whether different populations exist at pH levels 7, 4.5, and 2.5. Using growth-based methods provides model organisms for use in the future to predict potential activities and limitations of these organisms and to develop possible control methods. Thiosulfate-fed enrichment cultures were monitored for approximately 1 year. The results showed that the enrichments at pH 4.5 and 7 were established quicker than at pH 2.5. Different microbial community structures were found among the 3 pH environments. The sulfur-oxidizing microorganisms identified were most closely related to Halothiobacillus neapolitanus, Achromobacter spp., and Curtobacterium spp. While microorganisms related to Chitinophagaceae and Acidocella spp. were identified as the only possible iron-oxidizing and -reducing microbes. These results contribute to the general knowledge of the relatively understudied microbial communities that exist in pyritic oil sands tailings and indicate these communities may have a potential role in ARD generation, which may have implications for future tailings management.

Protein and lipid deposition rates in male broiler chickens : separate responses to amino acids and protein-free energy

NARCIS (Netherlands)

Eits, R.M.; Kwakkel, R.P.; Verstegen, M.W.A.; Stoutjesdijk, P.; Greef, de K.H.

2002-01-01

Two experiments of similar design were conducted with male broiler chickens over two body weight ranges, 200 to 800 g in Experiment 1 and 800 to 1,600 g in Experiment 2. The data were used to test the hypothesis that protein deposition rate increases (linearly) with increasing amino acid intake,

The role and origin of dilatant structural environments in the spatial control of geo-economic deposits

International Nuclear Information System (INIS)

Rosello, E.

2010-01-01

A major controlling the geometry, size and spatial location of the mineralization is the tectonic structure. This control is indeed essential in epigenetic deposits, where the structure is the main factor to determine the circulation, precipitation, and in many cases the generation of hydrothermal solutions associated with mineral deposits and / or alterations. Therefore, learning the type of structural control that a particular deposit is charged on a particular aspect and of fundamental importance not only in yacimientología to contribute to the genetic knowledge but also in economic terms to provide ideas and guidance in tasks prospecting, exploration and mineral exploitation

Danburite decomposition by hydrochloric acid

International Nuclear Information System (INIS)

Mamatov, E.D.; Ashurov, N.A.; Mirsaidov, U.

2011-01-01

Present article is devoted to decomposition of danburite of Ak-Arkhar Deposit of Tajikistan by hydrochloric acid. The interaction of boron containing ores of Ak-Arkhar Deposit of Tajikistan with mineral acids, including hydrochloric acid was studied. The optimal conditions of extraction of valuable components from danburite composition were determined. The chemical composition of danburite of Ak-Arkhar Deposit was determined as well. The kinetics of decomposition of calcined danburite by hydrochloric acid was studied. The apparent activation energy of the process of danburite decomposition by hydrochloric acid was calculated.

Thickness control in electrophoretic deposition of WO3 nanofiber thin films for solar water splitting

International Nuclear Information System (INIS)

Fang, Yuanxing; Lee, Wei Cheat; Canciani, Giacomo E.; Draper, Thomas C.; Al-Bawi, Zainab F.; Bedi, Jasbir S.; Perry, Christopher C.; Chen, Qiao

2015-01-01

Graphical abstract: - Highlights: • A novel method combining electrospinning and electrophoretic deposition was established for the creation of nanostructured semiconductor thin films. • The created thin films displayed a high chemical stability with a controllable thickness. • The PEC water splitting performance of the thin films was optimized by fine-tuning the thickness of the films. • A maximum photoconversion efficiency was achieved by 18 μm nanofibrous thin films. - Abstract: Electrophoretic deposition (EPD) of ground electrospun WO 3 nanofibers was applied to create photoanodes with controlled morphology for the application of photoelectrochemical (PEC) water splitting. The correlations between deposition parameters and film thicknesses were investigated with theoretical models to precisely control the morphology of the nanostructured porous thin film. The photoconversion efficiency was further optimized as a function of film thickness. A maximum photoconversion efficiency of 0.924% from electrospun WO 3 nanofibers that EPD deposited on a substrate was achieved at a film thickness of 18 μm.

Leaching of cell wall components caused by acid deposition on fir needles and trees

Energy Technology Data Exchange (ETDEWEB)

Shigihara, Ado [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan)], E-mail: r200670202@kanagawa-u.ac.jp; Matsumoto, Kiyoshi [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan); Sakurai, Naoki [Faculty of Integrated Arts and Science, Hiroshima University, 1-7-1, Kagamiyama, Higashi-Hiroshima, 739-8521 (Japan); Igawa, Manabu [Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama 221-8686 (Japan)

2008-07-15

Virgin fir forests have been declining since the 1960s at Mt. Oyama, which is located at the eastern edge of the Tanzawa Mountains and adjacent to the Kanto plain in Japan. An acid fog frequently occurs in the mountains. We collected throughfall and stemflow under fir trees and rainfall every week during January-December 2004 at Mt. Oyama to clarify the influence of acid fog on the decline of fir (Abies firma) needles. In relation to throughfall and stemflow, D-mannose, D-galactose, and D-glucose are the major neutral sugar components; only D-glucose is a major component of rainfall. The correlation coefficient between the total neutral sugars and uronic acid (as D-galacturonic acid), which is a key component of the cross-linking between pectic polysaccharides, was high except for rainfall. The leached amount of calcium ion, neutral sugars, uronic acid, and boron is related to the nitrate ion concentration in throughfall. Results of a laboratory exposure experiment using artificial fog water simulating the average composition of fog water observed at Mt. Oyama (simulated acid fog: SAF) on the fir seedling needles also shows a large leaching of these components from the cell walls of fir needles. The leaching amount increased concomitantly with decreasing pH of the SAF solution. We also observed that a dimeric rhamnogalacturonan II-borate complex (dRG-II-B) that exists in the cell wall as pectic polysaccharide was converted to monomeric RG-II (mRG-II) by the leaching of calcium ion and boron. Results not only of field observations but also those of laboratory experiments indicate a large effect of acid depositions on fir needles.

Deposition of controllable preferred orientation silicon films on glass by inductively coupled plasma chemical vapor deposition

International Nuclear Information System (INIS)

Li Junshuai; Wang Jinxiao; Yin Min; Gao Pingqi; He Deyan; Chen Qiang; Li Yali; Shirai, Hajime

2008-01-01

An inductively coupled plasma (ICP) system with the adjustable distance between the inductance coil and substrates was designed to effectively utilize the spatial confinement of ICP discharge, and then control the gas-phase transport process. The effects of the gas phase processes on the crystallinity and preferred orientation of silicon films deposited on glass were systematically investigated. The investigation was conducted in the ICP-chemical vapor deposition process with the precursor gas of a SiH 4 /H 2 mixture at a substrate temperature of 350 deg. Highly crystallized silicon films with different preferred orientations, (111) or (220), could be selectively deposited by adjusting the SiH 4 dilution ratio [R=[SiH 4 ]/([SiH 4 ]+[H 2 ])] or total working pressure. When the total working pressure is 20 Pa, the crystallinity of the silicon films increases with the increase of the SiH 4 dilution ratio, while the preferred orientation was changed from (111) to (220). In the case of the fixed SiH 4 dilution (10%), the silicon film with I (220) /I (111) of about 3.5 and Raman crystalline fraction of about 89.6% has been deposited at 29.7 nm/min when the total working pressure was increased to 40 Pa. At the fixed SiH 4 partial pressure of 2 Pa, the film crystallinity decreases and the preferred orientation is always (111) with increasing the H 2 partial pressure from 18 to 58 Pa. Atomic force microscope reveals that the film deposited at a relatively high H 2 partial pressure has a very rough surface caused by the devastating etching of H atoms to the silicon network

Transcriptomic Analysis Identifies Candidate Genes Related to Intramuscular Fat Deposition and Fatty Acid Composition in the Breast Muscle of Squabs (Columba

Directory of Open Access Journals (Sweden)

Manhong Ye

2016-07-01

Full Text Available Despite the fact that squab is consumed throughout the world because of its high nutritional value and appreciated sensory attributes, aspects related to its characterization, and in particular genetic issues, have rarely been studied. In this study, meat traits in terms of pH, water-holding capacity, intramuscular fat content, and fatty acid profile of the breast muscle of squabs from two meat pigeon breeds were determined. Breed-specific differences were detected in fat-related traits of intramuscular fat content and fatty acid composition. RNA-Sequencing was applied to compare the transcriptomes of muscle and liver tissues between squabs of two breeds to identify candidate genes associated with the differences in the capacity of fat deposition. A total of 27 differentially expressed genes assigned to pathways of lipid metabolism were identified, of which, six genes belonged to the peroxisome proliferator-activated receptor signaling pathway along with four other genes. Our results confirmed in part previous reports in livestock and provided also a number of genes which had not been related to fat deposition so far. These genes can serve as a basis for further investigations to screen markers closely associated with intramuscular fat content and fatty acid composition in squabs. The data from this study were deposited in the National Center for Biotechnology Information (NCBI’s Sequence Read Archive under the accession numbers SRX1680021 and SRX1680022. This is the first transcriptome analysis of the muscle and liver tissue in Columba using next generation sequencing technology. Data provided here are of potential value to dissect functional genes influencing fat deposition in squabs.

Chemical Controls of Ozone Dry Deposition to the Sea Surface Microlayer

Science.gov (United States)

Carpenter, L.; Chance, R.; Tinel, L.; Saint, A.; Sherwen, T.; Loades, D.; Evans, M. J.; Boxhall, P.; Hamilton, J.; Stolle, C.; Wurl, O.; Ribas-Ribas, M.; Pereira, R.

2017-12-01

Oceanic dry deposition of atmospheric ozone (O3) is both the largest and most uncertain O3 depositional sink, and is widely acknowledged to be controlled largely by chemical reactions in the sea surface microlayer (SML) involving iodide (I-) and dissolved organic material (DOM). These reactions not only determine how quickly O3 can be removed from the atmosphere, but also result in emissions of trace gases including volatile organic compounds and may constitute a source of secondary organic aerosols to the marine atmosphere. Iodide concentrations at the sea surface vary by approximately an order of magnitude spatially, leading to more than fivefold variation in ozone deposition velocities (and volatile iodine fluxes). Sea-surface temperature is a reasonable predictor of [I-], however two recent parameterisations for surface I- differ by a factor of two at low latitudes. The nature and reactivity of marine DOM to O3 is almost completely unknown, although studies have suggested approximately equivalent chemical control of I- and DOM on ozone deposition. Here we present substantial new measurements of oceanic I- in both bulk seawater and the overlying SML, and show improved estimates of the global sea surface iodide distribution. We also present analyses of water-soluble DOM isolated from the SML and bulk seawater, and corresponding laboratory studies of ozone uptake to bulk and SML seawater, with the aim of characterizing the reactivity of O3 towards marine DOM.

Evaluation of different approaches for modeling effects of acid rain on soils in China

International Nuclear Information System (INIS)

Larssen, T.; Schnoor, J.L.; Seip, H.M.; Dawei, Z.

2000-01-01

Acid deposition is an environmental problem of increasing concern in China. Acidic soils are common in the southern part of the country and soil acidification caused by acid deposition is expected to occur. Here we test and apply two different approaches for modeling effects of acid deposition and compare results with observed data from sites throughout southern China. The dynamic model MAGIC indicates that, during the last few decades, soil acidification rates have increased considerably due to acid deposition. This acidification will continue if sulfur deposition is not reduced, and if reduced more rapidly than base cation deposition. With the Steady State Mass Balance model (SSMB), and assuming that a molar ratio of Ca 2+ /Al 3+ <1 in soil water is harmful to vegetation, we estimate a slight probability for exceedance of the critical load for present deposition rates. Results from both modeling approaches show a strong dependence with deposition of base cations as well as sulfur. Hence, according to the models, changes in emission control of alkaline particulate matter prior to sulfur dioxide will be detrimental to the environment. Model calculations are, however, uncertain, particularly because available data on base cation deposition fluxes are scarce, and that model formulation of aluminum chemistry does not fully reproduce observations. An effort should be made to improve our present knowledge regarding deposition fluxes. Improvements to the model are suggested. Our work indicates that the critical loads presented in the regional acid deposition assessment model RAINS-Asia are too stringent. We find weaknesses in the SSMB approach, developed for northern European conditions, when applying it to Chinese conditions. We suggest an improved effort to revise the risk parameters for use in critical load estimates in China

Replacing dietary nonessential amino acids with ammonia nitrogen does not alter amino acid profile of deposited protein in the carcass of growing pigs fed a diet deficient in nonessential amino acid nitrogen.

Science.gov (United States)

Mansilla, W D; Htoo, J K; de Lange, C F M

2017-10-01

Amino acid usage for protein retention, and, consequently, the AA profile of retained protein, is the main factor for determining AA requirements in growing animals. The objective of the present study was to determine the effect of supplementing ammonia N on whole-body N retention and the AA profile of retained protein in growing pigs fed a diet deficient in nonessential AA (NEAA) N. In total, 48 barrows with a mean initial BW of 13.6 kg (SD 0.7) were used. At the beginning of the study, 8 pigs were euthanized for determination of initial protein mass. The remaining animals were individually housed and fed 1 of 5 dietary treatments. A common basal diet (95% of experimental diets) was formulated to meet the requirements for all essential AA (EAA) but to be deficient in NEAA N (CP = 8.01%). The basal diet was supplemented (5%) with cornstarch (negative control) or 2 N sources (ammonia or NEAA) at 2 levels each to supply 1.35 or 2.70% extra CP. The final standardized ileal digestible (SID) NEAA content in the high-NEAA-supplemented diet (positive control) was based on the NEAA profile of whole-body protein of 20-kg pigs, and it was expected to reduce the endogenous synthesis of NEAA. Pigs were fed at 3.0 times maintenance energy requirements for ME in 3 equal meals daily. At the end of a 3-wk period, pigs were euthanized and the carcass and visceral organs were weighed, frozen, and ground for determination of protein mass. From pigs in the initial, negative control, high-ammonia, and high-NEAA groups, AA contents in the carcass and pooled visceral organs were analyzed to determine the total and deposited protein AA profile, dietary EAA efficiencies, and minimal de novo synthesis of NEAA. Carcass weight and whole-body N retention linearly increased ( 0.10) between N sources, but Cys content increased ( ammonia in visceral organ protein and deposited protein. The dietary SID EAA efficiency for increasing EAA deposition in whole-body protein increased ( 0.10) between N

Deposition of lignin droplets produced during dilute acid pretreatment of maize stems retards enzymatic hydrolysis of cellulose.

Science.gov (United States)

Selig, Michael J; Viamajala, Sridhar; Decker, Stephen R; Tucker, Melvin P; Himmel, Michael E; Vinzant, Todd B

2007-01-01

Electron microscopy of lignocellulosic biomass following high-temperature pretreatment revealed the presence of spherical formations on the surface of the residual biomass. The hypothesis that these droplet formations are composed of lignins and possible lignin carbohydrate complexes is being explored. Experiments were conducted to better understand the formation of these "lignin" droplets and the possible implications they might have on the enzymatic saccharification of pretreated biomass. It was demonstrated that these droplets are produced from corn stover during pretreatment under neutral and acidic pH at and above 130 degrees C, and that they can deposit back onto the surface of residual biomass. The deposition of droplets produced under certain pretreatment conditions (acidic pH; T > 150 degrees C) and captured onto pure cellulose was shown to have a negative effect (5-20%) on the enzymatic saccharification of this substrate. It was noted that droplet density (per unit area) was greater and droplet size more variable under conditions where the greatest impact on enzymatic cellulose conversion was observed. These results indicate that this phenomenon has the potential to adversely affect the efficiency of enzymatic conversion in a lignocellulosic biorefinery.

Effects of chicory inulin on serum metabolites of uric acid, lipids, glucose, and abdominal fat deposition in quails induced by purine-rich diets.

Science.gov (United States)

Lin, Zhijian; Zhang, Bing; Liu, Xiaoqing; Jin, Rui; Zhu, Wenjing

2014-11-01

Inulin, a group of dietary fibers, is reported to improve the metabolic disorders. In the present study, we investigated the effects of chicory inulin on serum metabolites of uric acid (UA), lipids, glucose, and abdominal fat deposition in quail model induced by a purine-rich diet. In this study, 60 male French quails were randomly allocated to five groups: CON (control group), MOD (model group), BEN (benzbromarone-treated group), CHI-H (high-dosage chicory inulin-treated group), and CHI-L (low-dosage chicory inulin-treated group). The serum UA level was significantly increased in the model group from days 7 to 28, as well as triglyceride (TG) and free fatty acid (FFA) increased later in the experimental period. The abdominal fat ratio was increased on day 28. Benzbromarone can decrease UA levels on days 14 and 28. The high and low dosage of chicory inulin also decreased serum UA levels on days 7, 14, and 28. The abdominal fat ratio, activity, and protein of acetyl-CoA carboxylase (ACC) were decreased in chicory inulin-treated groups. The activities of xanthine oxidase (XOD) and fatty acid synthase (FAS) were increased in the model group and decreased in the benzbromarone and chicory inulin groups. This study evaluated a quail model of induced hyperuricemia with other metabolic disorders caused by a high-purine diet. The results indicated that a purine-rich diet might contribute to the development of hyperuricemia, hypertriglyceridemia, and abdominal obesity. Chicory inulin decreased serum UA, TG, and abdominal fat deposition in a quail model of hyperuricemia by altering the ACC protein expression and FAS and XOD activities.

2.4. The kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit

International Nuclear Information System (INIS)

Mirsaidov, U.M.; Kurbonov, A.S.; Mamatov, E.D.

2015-01-01

Present article is devoted to kinetics of hydrochloric-acid decomposition of calcined concentrate of boron raw material of Ak-Arkhar Deposit. The experimental data of dependence of hydrochloric-acid decomposition of calcined boron raw material for boron oxide extraction on temperature (20-80 deg C) and process duration (15-60 min) were considered. It was defined that at temperature increasing the boron oxide extraction from borosilicate raw material increases from 24.1 till 86.8%. The constants of decomposition rate of boron raw material were calculated.

The response of gene expression associated with lipid metabolism, fat deposition and fatty acid profile in the longissimus dorsi muscle of Gannan yaks to different energy levels of diets.

Directory of Open Access Journals (Sweden)

Chao Yang

Full Text Available The energy available from the diet, which affects fat deposition in vivo, is a major factor in the expression of genes regulating fat deposition in the longissimus dorsi muscle. Providing high-energy diets to yaks might increase intramuscular fat deposition and fatty acid concentrations under a traditional grazing system in cold seasons. A total of fifteen adult castrated male yaks with an initial body weight 274.3 ± 3.14 kg were analyzed for intramuscular adipose deposition and fatty acid composition. The animals were divided into three groups and fed low-energy (LE: 5.5 MJ/kg, medium-energy (ME: 6.2 MJ/kg and high-energy (HE: 6.9 MJ/kg diets, respectively. All animals were fed ad libitum twice daily at 08:00-09:00 am and 17:00-18:00 pm and with free access to water for 74 days, including a 14-d period to adapt to the diets and the environment. Intramuscular fat (IMF content, fatty acid profile and mRNA levels of genes involved in fatty acid synthesis were determined. The energy levels of the diets significantly (P<0.05 affected the content of IMF, total SFA, total MUFA and total PUFA. C16:0, C18:0 and C18:1n9c account for a large proportion of total fatty acids. Relative expression of acetyl-CoA carboxylase (ACACA, fatty acid synthase (FASN, stearoyl-CoA desaturase (SCD, sterol regulatory element-binding protein-1c (SREBP-1c, peroxisome proliferator-activated receptor γ (PPARγ and fatty acid-binding protein 4 (FABP4 was greater in HE than in LE yaks (P<0.05. Moreover, ME yaks had higher (P<0.05 mRNA expression levels of PPARγ, ACACA, FASN, SCD and FABP4 than did the LE yaks. The results demonstrate that the higher energy level of the diets increased IMF deposition and fatty acid content as well as increased intramuscular lipogenic gene expression during the experimental period.

Factors controlling deposits in recovery boilers -particle formation and deposition; Soodakattilan likaantuminen ja siihen vaikuttavien tekijoeiden hallinta. Hiukkasten muodostuminen ja depositio

Energy Technology Data Exchange (ETDEWEB)

Kauppinen, E I; Mikkanen, P; Tapper, U; Ylaetalo, S; Jaervinen, R [VTT Chemical Technology, Espoo (Finland); Jokiniemi, J K; Pyykoenen, J; Eskola, A [VTT Energy, Espoo (Finland)

1997-10-01

In this project the aim is to find critical factors controlling the deposit formation in the recovery boilers. Focus is on particle formation, growth and deposition. During year 1995 the aerosol particle formation was studied by an experimental study within the recovery boiler furnace and by a sensitivity study with the ABC (Aerosol Behaviour in Combustion) computer code. During year 1996 the experimental studies on the aerosol particle formation continued within the furnace and the deposition mechanisms for carry over particles were included in the ABC code and sensitivity studies of the deposition were carried out. The experimental study confirmed the fact that the particles are already formed in the recovery boiler furnace. The particle formation is initiated in the boundary layer of the burning droplet or char bed, where metals are vaporised and oxidised to form tiny seed particles

Controls of nitrous oxide emission after simulated cattle urine deposition

DEFF Research Database (Denmark)

Baral, Khagendra Raj; Thomsen, Anton Gårde; Olesen, Jørgen E

2014-01-01

Urine deposited during grazing is a significant source of atmospheric nitrous oxide (N2O). The potential for N2O emissions from urine patches is high, and a better understanding of controls is needed. This study investigated soil nitrogen (N) dynamics and N2O emissions from cattle urine...

Acid Rain

Science.gov (United States)

Bricker, Owen P.; Rice, Karen C.

1995-01-01

Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidic substances - rain, snow, fog, acidic dry particulates, aerosols, and acid-forming gases. Water in the atmosphere reacts with certain atmospheric gases to become acidic. For example, water reacts with carbon dioxide in the atmosphere to produce a solution with a pH of about 5.6. Gases that produce acids in the presence of water in the atmosphere include carbon dioxide (which converts to carbonic acid), oxides of sulfur and nitrogen (which convert to sulfuric and nitric acids}, and hydrogen chloride (which converts to hydrochloric acid). These acid-producing gases are released to the atmosphere through natural processes, such as volcanic emissions, lightning, forest fires, and decay of organic matter. Accordingly, precipitation is slightly acidic, with a pH of 5.0 to 5.7 even in undeveloped areas. In industrialized areas, most of the acid-producing gases are released to the atmosphere from burning fossil fuels. Major emitters of acid-producing gases include power plants, industrial operations, and motor vehicles. Acid-producing gases can be transported through the atmosphere for hundreds of miles before being converted to acids and deposited as acid rain. Because acids tend to build up in the atmosphere between storms, the most acidic rain falls at the beginning of a storm, and as the rain continues, the acids "wash out" of the atmosphere.

Geochemical and modal data for igneous rocks associated with epithermal mineral deposits

Science.gov (United States)

du Bray, Edward A.

2014-01-01

The purposes of this report are to (1) present available geochemical and modal data for igneous rocks associated with epithermal mineral deposits and (2) to make those data widely and readily available for subsequent, more in-depth consideration and interpretation. Epithermal precious and base-metal deposits are commonly associated with subduction-related calc-alkaline to alkaline arc magmatism as well as back-arc continental rift magmatism. These deposits form in association with compositionally diverse extrusive and intrusive igneous rocks. Temperature and depth regimes prevailing during deposit formation are highly variable. The deposits form from hydrothermal fluids that range from acidic to near-neutral pH, and they occur in a variety of structural settings. The disparate temperature, pressure, fluid chemistry, and structural controls have resulted in deposits with wide ranging characteristics. Economic geologists have employed these characteristics to develop classification schemes for epithermal deposits and to constrain the important genetic processes responsible for their formation.

Field electron emission characteristics of chemical vapour deposition diamond films with controlled sp2 phase concentration

International Nuclear Information System (INIS)

Lu, X.; Yang, Q.; Xiao, C.; Hirose, A.

2008-01-01

Diamond films were synthesized in a microwave plasma-enhanced chemical vapour deposition reactor. The microstructure and surface morphology of deposited films were characterized by Raman spectroscope and scanning electron microscope. The sp 2 phase concentration in diamond films was varied and its effect on the field electron emission (FEE) properties was investigated. Diamond films deposited under higher methane concentration exhibit better FEE property including lower turn-on electric field and larger emission current. The predominating factor modifying the FEE property is presumed to be the increase of sp 2 phase concentration. The influence of bias voltage on the FEE property of diamond films is not monotonic. Postgrowth acid treatment reduces the sp 2 phase content in diamond films without changing diamond grain sizes. The corresponding FEE property was degraded

Thickness control in electrophoretic deposition of WO{sub 3} nanofiber thin films for solar water splitting

Energy Technology Data Exchange (ETDEWEB)

Fang, Yuanxing; Lee, Wei Cheat; Canciani, Giacomo E.; Draper, Thomas C.; Al-Bawi, Zainab F. [Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ (United Kingdom); Bedi, Jasbir S. [School of Public Health & Zoonoses, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana 141004 Punjab (India); Perry, Christopher C. [Division of Biochemistry, School of Medicine, Loma Linda University, Loma Linda, CA 92350 (United States); Chen, Qiao, E-mail: qiao.chen@sussex.ac.uk [Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ (United Kingdom)

2015-12-15

Graphical abstract: - Highlights: • A novel method combining electrospinning and electrophoretic deposition was established for the creation of nanostructured semiconductor thin films. • The created thin films displayed a high chemical stability with a controllable thickness. • The PEC water splitting performance of the thin films was optimized by fine-tuning the thickness of the films. • A maximum photoconversion efficiency was achieved by 18 μm nanofibrous thin films. - Abstract: Electrophoretic deposition (EPD) of ground electrospun WO{sub 3} nanofibers was applied to create photoanodes with controlled morphology for the application of photoelectrochemical (PEC) water splitting. The correlations between deposition parameters and film thicknesses were investigated with theoretical models to precisely control the morphology of the nanostructured porous thin film. The photoconversion efficiency was further optimized as a function of film thickness. A maximum photoconversion efficiency of 0.924% from electrospun WO{sub 3} nanofibers that EPD deposited on a substrate was achieved at a film thickness of 18 μm.

Deposition of Coating to Protect Waste Water Reservoir in Acidic Solution by Arc Thermal Spray Process

Directory of Open Access Journals (Sweden)

Han-Seung Lee

2018-01-01

Full Text Available The corrosion characteristics of 304 stainless steel (SS and titanium (Ti coatings deposited by the arc thermal spray process in pH 4 solution were assessed. The Ti-sprayed coating exhibits uniform, less porous, and adherent coating morphology compared to the SS-sprayed coating. The electrochemical study, that is, electrochemical impedance spectroscopy (EIS, revealed that as exposure periods to solution were increased, the polarization resistance (Rp decreased and the charge transfer resistance (Rct increased owing to corrosion of the metallic surface and simultaneously at the same time the deposition of oxide films/corrosion on the SS-sprayed surface, while Ti coating transformed unstable oxides into the stable phase. Potentiodynamic studies confirmed that both sprayed coatings exhibited passive tendency attributed due to the deposition of corrosion products on SS samples, whereas the Ti-sprayed sample formed passive oxide films. The Ti coating reduced the corrosion rate by more than six times compared to the SS coating after 312 h of exposure to sulfuric acid- (H2SO4- contaminated water solution, that is, pH 4. Scanning electron microscope (SEM results confirmed the uniform and globular morphology of the passive film on the Ti coating resulting in reduced corrosion. On the other hand, the corrosion products formed on SS-sprayed coating exhibit micropores with a net-like microstructure. X-ray diffraction (XRD revealed the presence of the composite oxide film on Ti-sprayed samples and lepidocrocite (γ-FeOOH on the SS-coated surface. The transformation of TiO and Ti3O into TiO2 (rutile and anatase and Ti3O5 after 312 h of exposure to H2SO4 acid reveals the improved corrosion resistance properties of Ti-sprayed coating.

Voltage-Controlled Spray Deposition of Multiwalled Carbon Nanotubes on Semiconducting and Insulating Substrates

Science.gov (United States)

Maulik, Subhodip; Sarkar, Anirban; Basu, Srismrita; Daniels-Race, Theda

2018-05-01

A facile, cost-effective, voltage-controlled, "single-step" method for spray deposition of surfactant-assisted dispersed carbon nanotube (CNT) thin films on semiconducting and insulating substrates has been developed. The fabrication strategy enables direct deposition and adhesion of CNT films on target samples, eliminating the need for substrate surface functionalization with organosilane binder agents or metal layer coatings. Spray coating experiments on four types of sample [bare silicon (Si), microscopy-grade glass samples, silicon dioxide (SiO2), and polymethyl methacrylate (PMMA)] under optimized control parameters produced films with thickness ranging from 40 nm to 6 μm with substantial surface coverage and packing density. These unique deposition results on both semiconducting and insulator target samples suggest potential applications of this technique in CNT thin-film transistors with different gate dielectrics, bendable electronics, and novel CNT-based sensing devices, and bodes well for further investigation into thin-film coatings of various inorganic, organic, and hybrid nanomaterials on different types of substrate.

Process control of high rate microcrystalline silicon based solar cell deposition by optical emission spectroscopy

International Nuclear Information System (INIS)

Kilper, T.; Donker, M.N. van den; Carius, R.; Rech, B.; Braeuer, G.; Repmann, T.

2008-01-01

Silicon thin-film solar cells based on microcrystalline silicon (μc-Si:H) were prepared in a 30 x 30 cm 2 plasma-enhanced chemical vapor deposition reactor using 13.56 or 40.68 MHz plasma excitation frequency. Plasma emission was recorded by optical emission spectroscopy during μc-Si:H absorber layer deposition at deposition rates between 0.5 and 2.5 nm/s. The time course of SiH * and H β emission indicated strong drifts in the process conditions particularly at low total gas flows. By actively controlling the SiH 4 gas flow, the observed process drifts were successfully suppressed resulting in a more homogeneous i-layer crystallinity along the growth direction. In a deposition regime with efficient usage of the process gas, the μc-Si:H solar cell efficiency was enhanced from 7.9 % up to 8.8 % by applying process control

Dynamic Control of Particle Deposition in Evaporating Droplets by an External Point Source of Vapor.

Science.gov (United States)

Malinowski, Robert; Volpe, Giovanni; Parkin, Ivan P; Volpe, Giorgio

2018-02-01

The deposition of particles on a surface by an evaporating sessile droplet is important for phenomena as diverse as printing, thin-film deposition, and self-assembly. The shape of the final deposit depends on the flows within the droplet during evaporation. These flows are typically determined at the onset of the process by the intrinsic physical, chemical, and geometrical properties of the droplet and its environment. Here, we demonstrate deterministic emergence and real-time control of Marangoni flows within the evaporating droplet by an external point source of vapor. By varying the source location, we can modulate these flows in space and time to pattern colloids on surfaces in a controllable manner.

Effect of PW12–GPK on the acid characteristics of Ni-, Pd- and Pt- catalysts deposited onto pillared Al montmorillonite

Directory of Open Access Journals (Sweden)

D. Zhumadullaev

2012-03-01

Full Text Available Acid characteristics of Ni-, Pd-, Pt- catalyzers , deposited to Al pillared CaH montmorillonite modified by heteropolyacid H3PW12O40·xH2O (PW12 by ammonia thermoadsorbtion method has been studied.

The regional costs and benefits of acid rain control

International Nuclear Information System (INIS)

Berkman, M.P.

1991-01-01

Congress recently enacted acid rain control legislation as part of the 1990 Clean Air Act Amendments following a decade-long debate among disparate regional interests. Although Congress succeeded in drafting a law acceptable to all regions, the regional costs and benefits of the legislation remain uncertain. The research presented here attempts to estimate the regional costs and benefits and the economic impacts of acid rain controls. These estimates are made using a modeling system composed of econometric, linear programming and input-output models. The econometric and linear programming components describe markets for electricity and coal. The outputs of these components including capital investment, electricity demand, and coal production are taken as exogenous inputs by a multiregional input-output model. The input-output model produces estimates of changes in final demand, gross output, and employment. The utility linear programming model also predicts sulfur dioxide emissions (an acid-rain precursor). According to model simulations, the costs of acid rain control exceed the benefits for many regions including several regions customarily thought to be the major beneficiaries of acid rain control such as New England

The smog-fog-smog cycle and acid deposition

Science.gov (United States)

Pandis, Spyros N.; Seinfeld, John H.; Pilinis, Christodoulos

1990-10-01

A model including descriptions of aerosol and droplet microphysics, gas and aqueous-phase chemistry, and deposition is used to study the transformation of aerosol to fog droplets and back to aerosol in an urban environment. Fogs in polluted environments have the potential to increase aerosol sulfate concentrations but at the same time to cause reductions in the aerosol concentration of nitrate, chloride, ammonium and sodium and well as in the total aerosol mass concentration. The sulfate produced during fog episodes favors the aerosol particles that have access to most of the fog liquid water which are usually the large particles. Aerosol scavenging efficiencies of around 80 percent are calculated for urban fogs. Sampling and subsequent mixing of fog droplets of different sizes may result in measured concentrations that are not fully representative of the fogwater chemical composition and can introduce errors in the reported values of the ionic species deposition velocities. Differences in the major ionic species deposition velocities can be explained by their distribution over the droplet size spectrum and can be correlated with the species average diameter. Two different expressions are derived for use in fog models for the calculation of the liquid water deposition velocity during fog growth and dissipation stages.

Comparison of folic acid levels in schizophrenic patients and control groups

Science.gov (United States)

Arthy, C. C.; Amin, M. M.; Effendy, E.

2018-03-01

Folic acid deficiency is a risk factor for schizophrenia through epidemiology, biochemistry and gene-related studies. Compared with healthy people, schizophrenic patients may have high homocysteine plasma values and homocysteine or low levels of folic acid, which seems to correlate with extrapyramidal motor symptoms caused by neuroleptic therapy and with symptoms of schizophrenia. In this present study, we focus on the difference of folic acid level between schizophrenic patient and control group. The study sample consisted of schizophrenic patients and 14 people in the control group and performed blood sampling to obtain the results of folic acid levels. The folic acid level in both groups was within normal range, but the schizophrenic patient group had lower mean folic acid values of 5.00 ng/ml (sb 1.66), compared with the control group with mean folic acid values of 10.75 ng/ml (sb 4.33). there was the group of the control group had a higher value of folic acid than the schizophrenic group.

Whole-lake algal responses to a century of acidic industrial deposition on the Canadian Shield

International Nuclear Information System (INIS)

Vinebrooke, R.D.; Dixit, S.S.; Graham, M.D.; Gunn, J.M.; Chen, Y.-W.; Belzile, N.

2002-01-01

A century of cultural acidification is hypothesized to have altered algal community structure in boreal lakes. To date, this hypothesis has remained untested because of both the lack of data predating the onset of industrial pollution and incomplete estimates of whole-lake algal community structure. High-pressure liquid chromatography (HPLC) of sedimentary pigments was used to quantify whole-lake algal responses to acid deposition in six boreal lakes located in Killarney Park, Ontario, Canada. Concomitant significant increases in chlorophyll and carotenoid concentrations, diatom-inferred lake acidity, and metal levels since 1900 suggested that algal abundances in four acidified lakes and one small, circumneutral lake were enhanced by aerial pollution. An alternate explanation is that increased acidity and underwater light availability in the acidified lakes shifted algal abundance towards phytobenthos and deepwater phytoplankton, whose pigment signatures were better preserved in the sediments. Taxonomically diagnostic pigment stratigraphies were consistent with shifts in algal community structure towards filamentous green phytobenthos and deepwater phytoflagellates in the acidified lakes. Our findings suggest that decades of aerial pollution have altered the base of foodwebs in boreal lakes, potentially rendering them less resilient to other environmental stressors. (author)

Analysis on ore-controlling factors of Zhajistan uranium deposit, Xinjiang

International Nuclear Information System (INIS)

A Zhongming

2000-01-01

The geologic-structural background where the Zhajistan uranium deposit is located, and sedimentary features of the basin, as well as ore-controlling factors such as the uranium source, the reductant, hydrogeologic conditions and development features of interlayer oxidation zone in Zhajistan, are analysed. Then the author proposes the most favourable sedimentary cycle for uranium metallogenesis and the most favourable prospecting areas

Impacts of atmospheric pollution on the plant communities of British acid grasslands

Energy Technology Data Exchange (ETDEWEB)

Payne, Richard J., E-mail: r.payne@mmu.ac.uk [School of Science and the Environment, Manchester Metropolitan University, Chester St., Manchester M1 5GD (United Kingdom); Geography, School of Environment and Development, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Stevens, Carly J. [Faculty of Science, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster LA1 4YQ (United Kingdom); Dise, Nancy B. [School of Science and the Environment, Manchester Metropolitan University, Chester St., Manchester M1 5GD (United Kingdom); Gowing, David J. [Faculty of Science, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Pilkington, Michael G.; Phoenix, Gareth K. [Department of Animal and Plant Sciences, Alfred Denny Building, University of Sheffield, Sheffield S10 2TN (United Kingdom); Emmett, Bridget A. [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Ashmore, Michael R. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom)

2011-10-15

Air pollutants are recognised as important agents of ecosystem change but few studies consider the effects of multiple pollutants and their interactions. Here we use ordination, constrained cluster analysis and indicator value analyses to identify potential environmental controls on species composition, ecological groupings and indicator species in a gradient study of UK acid grasslands. The community composition of these grasslands is related to climate, grazing, ozone exposure and nitrogen deposition, with evidence for an interaction between the ecological impacts of base cation and nitrogen deposition. Ozone is a key agent in species compositional change but is not associated with a reduction in species richness or diversity indices, showing the subtly different drivers on these two aspects of ecosystem degradation. Our results demonstrate the effects of multiple interacting pollutants, which may collectively have a greater impact than any individual agent. - Highlights: > Ozone exposure, N and base cation deposition modify UK acid grassland composition. > Ozone influences community composition without reducing species richness. > Nitrogen and base cation deposition have interacting impacts. > Distinct species responses to pollutants suggest potential for bioindication. - Ozone exposure and nitrogen deposition have distinct but additive impacts on the plant communities of British acid grasslands.

Impacts of atmospheric pollution on the plant communities of British acid grasslands

International Nuclear Information System (INIS)

Payne, Richard J.; Stevens, Carly J.; Dise, Nancy B.; Gowing, David J.; Pilkington, Michael G.; Phoenix, Gareth K.; Emmett, Bridget A.; Ashmore, Michael R.

2011-01-01

Air pollutants are recognised as important agents of ecosystem change but few studies consider the effects of multiple pollutants and their interactions. Here we use ordination, constrained cluster analysis and indicator value analyses to identify potential environmental controls on species composition, ecological groupings and indicator species in a gradient study of UK acid grasslands. The community composition of these grasslands is related to climate, grazing, ozone exposure and nitrogen deposition, with evidence for an interaction between the ecological impacts of base cation and nitrogen deposition. Ozone is a key agent in species compositional change but is not associated with a reduction in species richness or diversity indices, showing the subtly different drivers on these two aspects of ecosystem degradation. Our results demonstrate the effects of multiple interacting pollutants, which may collectively have a greater impact than any individual agent. - Highlights: → Ozone exposure, N and base cation deposition modify UK acid grassland composition. → Ozone influences community composition without reducing species richness. → Nitrogen and base cation deposition have interacting impacts. → Distinct species responses to pollutants suggest potential for bioindication. - Ozone exposure and nitrogen deposition have distinct but additive impacts on the plant communities of British acid grasslands.

Controlling droplet-based deposition uniformity of long silver nanowires by micrometer scale substrate patterning

International Nuclear Information System (INIS)

Basu, Nandita; Cross, Graham L W

2015-01-01

We report control of droplet-deposit uniformity of long silver nanowires suspended in solutions by microscopic influence of the liquid contact line. Substrates with microfabricated line patterns with a pitch far smaller than mean wire length lead to deposit thickness uniformity compared to unpatterned substrates. For high boiling-point solvents, two significant effects were observed: The substrate patterns suppressed coffee ring staining, and the wire deposits exhibited a common orientation lying perpendicular over top the lines. The latter result is completely distinct from previously reported substrate groove channeling effects. This work shows that microscopic influence of the droplet contact line geometry including the contact angle by altered substrate wetting allows significant and advantageous influence of deposition patterns of wire-like solutes as the drop dries. (paper)

Immobilization and controlled release of drug using plasma polymerized thin film

Energy Technology Data Exchange (ETDEWEB)

Myung, Sung-Woon [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of); Jung, Sang-Chul [Department of Environmental Engineering, Sunchon National University, Sunchon 540-742 (Korea, Republic of); Kim, Byung-Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju (Korea, Republic of)

2015-06-01

In this study, plasma polymerization of acrylic acid was employed to immobilize drug and control its release. Doxorubicin (DOX) was immobilized covalently on the glass surface deposited with plasma polymerized acrylic acid (PPAAc) thin film containing the carboxylic group. At first, the PPAAc thin film was coated on a glass surface at a pressure of 1.33 Pa and radio frequency (RF) discharge power of 20 W for 10 min. DOX was immobilized on the PPAAc deposition in a two environment of phosphate buffer saline (PBS) and dimethyl sulfoxide (DMSO) solutions. The DOX immobilized surface was characterized by scanning electron microscope, atomic force microscope and attenuated total reflection Fourier transform infrared spectroscopy. The DOX molecules were more immobilized in PBS than DMSO solution. The different immobilization and release profiles of DOX result from the solubility of hydrophobic DOX in aqueous and organic solutions. Second, in order to control the release of the drug, PPAAc thin film was covered over DOX dispersed layer. Different thicknesses and cross-linked PPAAc thin films by adjusting deposition time and RF discharge power were covered on the DOX layer dispersed. PPAAc thin film coated DOX layer reduced the release rate of DOX. The thickness control of plasma deposition allows controlling the release rate of drug. - Highlights: • Doxorubicin was immobilized on the surface of plasma polymerized acrylic acid thin film. • Release profile of doxorubicin was affected by aqueous and organic solutions. • Plasma polymerized acrylic acid thin film can be used to achieve controlled release.

Immobilization and controlled release of drug using plasma polymerized thin film

International Nuclear Information System (INIS)

Myung, Sung-Woon; Jung, Sang-Chul; Kim, Byung-Hoon

2015-01-01

In this study, plasma polymerization of acrylic acid was employed to immobilize drug and control its release. Doxorubicin (DOX) was immobilized covalently on the glass surface deposited with plasma polymerized acrylic acid (PPAAc) thin film containing the carboxylic group. At first, the PPAAc thin film was coated on a glass surface at a pressure of 1.33 Pa and radio frequency (RF) discharge power of 20 W for 10 min. DOX was immobilized on the PPAAc deposition in a two environment of phosphate buffer saline (PBS) and dimethyl sulfoxide (DMSO) solutions. The DOX immobilized surface was characterized by scanning electron microscope, atomic force microscope and attenuated total reflection Fourier transform infrared spectroscopy. The DOX molecules were more immobilized in PBS than DMSO solution. The different immobilization and release profiles of DOX result from the solubility of hydrophobic DOX in aqueous and organic solutions. Second, in order to control the release of the drug, PPAAc thin film was covered over DOX dispersed layer. Different thicknesses and cross-linked PPAAc thin films by adjusting deposition time and RF discharge power were covered on the DOX layer dispersed. PPAAc thin film coated DOX layer reduced the release rate of DOX. The thickness control of plasma deposition allows controlling the release rate of drug. - Highlights: • Doxorubicin was immobilized on the surface of plasma polymerized acrylic acid thin film. • Release profile of doxorubicin was affected by aqueous and organic solutions. • Plasma polymerized acrylic acid thin film can be used to achieve controlled release

Atmospheric concentrations and deposition of oxidised sulfur and nitrogen species at Petaling Jaya, Malaysia, 1993-1998

Energy Technology Data Exchange (ETDEWEB)

Ayers, G.P.; Gillett, R.W.; Manins, P.C. [CSIRO Atmospheric Research, Aspendale, VIC (Australia); Peng Leong Chow; Fook Lim Sze [Malaysian Meteorological Service, Petaling Jaya (Malaysia); Kong Cheah Wai [Tenaga Nasional R and D Berhad, Kajang (Malaysia)

2000-02-01

Wet-only rainwater composition, acid-precursor gas mixing ratios and aerosol loading were determined from weekly-averaged samples at Petaling Jaya, Malaysia, over the five year period from March 1993 to March 1998. Annual deposition fluxes of acidic sulfur and nitrogen species estimated from these data show this site to be heavily impacted by acidic deposition, with total oxidised sulfur plus nitrogen deposition in the range 277-480 meq m{sup -2} yr{sup -1}. Average contributions were 56% as sulfur species, 44% as nitrogen species, with wet deposition in this region of high rainfall accounting for 67% of total deposition. Thus total acid deposition fluxes were equivalent to levels that provided motivation for emissions reduction programs in both Europe and North America. The possibility of adverse environmental effects in Malaysia caused by acid deposition therefore merits serious consideration and assessment.

Physical and chemical controls (fO2, T, pH) of the opposite behaviour of U and Sn-W as examplified by hydrothermal deposits in France and Great-Britain, and solubility data

International Nuclear Information System (INIS)

Dubessy, J.; Nguyen-Trung, C.; Cathelineau, M.; Cuney, M.; Leroy, J.; Poty, B.; Ramboz, C.; Charoy, B.; Weisbrod, A.

1987-01-01

In uranium deposits, fO 2 and fS 2 of mineralizing fluids are higher than values fixed by the pyrite-hematite-magnetite triple point, as shown by uraninite-hematite and/or pyrite mineral association. The stability of quartz-K feldspar-muscovite paragenesis in the wall-rocks of hydrothermal U deposits indicates weakly acid pH. By contrast, in the Sn-W occurrences from the French Southern Massif Central, the fO 2 of mineralizing fluids is between Ni-NiO and Q-F-M buffers as shown by fluid inclusions. The pH of these fluids is weakly acid to weakly basic. Sn-W mineralizing fluids from Cornwall are by contrast purely aqueous and acid. Experimental data on UO 2 , SnO 2 , FeWO 4 , CaWO 4 solubility and metal species in fluids show that fO 2 > H-M are required for uranium transport whereas fO 2 ≤ Ni-NiO favours Sn transport. The fluid oxidation state has no direct influence on the transport and deposition of tungsten. The fO 2 control on the hydrothermal transport properties of these three metals is related on the one hand to the fluid and rock composition, and on the other hand to the minimal 320 0 C temperature required for homogeneous equilibria in the C-O-H system to control the oxidation state at low values. At high temperatures, Sn, Fe and Ca chloride complexes are more stable than carbonate and phosphate uranium complexes. All these results show that temperature and fO 2 account for the opposite behaviour of uranium and tin-tungsten in hydrothermal systems between 300 0 to 500 0 C

Kinetic study of formic acid oxidation on Ti/IrO{sub 2} electrodes prepared using the spin coating deposition technique

Energy Technology Data Exchange (ETDEWEB)

Fierro, Stephane, E-mail: stephane.fierro@epfl.c [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland); Comninellis, Christos [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland)

2010-09-30

In the first part of this paper, IrO{sub 2} electrodes produced by thermal decomposition of H{sub 2}IrCl{sub 6} precursor were manufactured using the spin coating deposition technique, where centrifugal forces spread the precursor solution with simultaneous evaporation of the solvent on the rotating Ti substrate. It was found using this technique, that it is possible to obtain thin and uniform IrO{sub 2} coatings with controlled loadings. The influence of the concentration of iridium salt in the precursor solution (c{sub 0}) as well as the influence of the rotation speed at which the substrate spins ({omega}) on the IrO{sub 2} loading have been studied using voltammetric charge measurements. From these results, a simple relation has been proposed for the estimation of the IrO{sub 2} loading for a given c{sub 0} and {omega}. In the second part of this paper and from measurements performed using different IrO{sub 2} loadings and formic acid concentrations, the kinetic parameters of the oxidation of formic acid have been quantitatively determined using a model that involves the redox couple IrO{sub 3}/IrO{sub 2} as mediator of this reaction. Furthermore, using the kinetic parameters obtained together with the Nernst equation and the I-V curves of the supporting electrolyte (1 M HClO{sub 4}), theoretical I-V curves could be constructed for different concentrations of formic acid and different IrO{sub 2} loadings.

Treatment of menorrhagia during menstruation: randomised controlled trial of ethamsylate, mefenamic acid, and tranexamic acid.

Science.gov (United States)

Bonnar, J; Sheppard, B L

1996-09-07

To compare the efficacy and acceptability of ethamsylate, mefenamic acid, and tranexamic acid for treating menorrhagia. Randomised controlled trial. A university department of obstetrics and gynaecology. 76 women with dysfunctional uterine bleeding. Treatment for five days from day 1 of menses during three consecutive menstrual periods. 27 patients were randomised to take ethamsylate 500 mg six hourly, 23 patients to take mefenamic acid 500 mg eight hourly, and 26 patients to take tranexamic acid 1 g six hourly. Menstrual loss measured by the alkaline haematin method in three control menstrual periods and three menstrual periods during treatment; duration of bleeding; patient's estimation of blood loss; sanitary towel usage; the occurrence of dysmenorrhoea; and unwanted events. Ethamsylate did not reduce mean menstrual blood loss whereas mefenamic acid reduced blood loss by 20% (mean blood loss 186 ml before treatment, 148 ml during treatment) and tranexamic acid reduced blood loss by 54% (mean blood loss 164 ml before treatment, 75 ml during treatment). Sanitary towel usage was significantly reduced in patients treated with mefenamic acid and tranexamic acid. Tranexamic acid given during menstruation is a safe and highly effective treatment for excessive bleeding. Patients with dysfunctional uterine bleeding should be offered medical treatment with tranexamic acid before a decision is made about surgery.

Effect of glycerin and formic acid in the efficiency of deposit on Zn-Ni, obtained by electrodeposition; Efeito da glicerina e do acido formico na eficiencia de deposito da liga Zn-Ni, obtido atraves de eletrodeposicao

Energy Technology Data Exchange (ETDEWEB)

Pedroza, G.A.G.; Souza, C.A.C.; Lima, L.R.P.A.; Ferreira, D.M. [Universidade Federal da Bahia - Escola Politecnica, BA (Brazil)

2010-07-01

Additives are added to the electrodeposition of metal coatings to improve the characteristics of the deposit. However, the objective was to investigate the effect of adding glycerin and formic acid in the deposition efficiency and deposit structure of zinc-nickel alloy obtained by electrodeposition. The depositions were made at a galvanostatic current density of 10 mA/cm{sup 2} to obtain a deposit of about 5 mm in thickness. The deposition efficiency was determined through measures of mass, chemical composition of the deposit in the presence and absence of additives was examined by X-ray Spectrometer Fluorescence (XRF) and surface characterization of coatings was performed by Scanning Electron Microscopy (SEM). The high levels of glycerin (0,07 M) and formic acid (0,26 M) in bath deposition increased the deposition efficiency of around 10% to 12% by mass, respectively. (author)

Preparation and characterization of thin organosilicon films deposited on SPR chip

Energy Technology Data Exchange (ETDEWEB)

Szunerits, Sabine [Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces (LEPMI), CNRS-INPG-UJF, 1130 rue de la piscine, BP 75, 38402 St. Martin d' Heres Cedex (France)], E-mail: sabine.szunerits@lepmi.inpg.fr; Rich, Sami Abou [Laboratoire de Genie des Procedes d' Interaction de Fluides Reactifs-Materiaux U.S.T.L., Cite Scientifique, 59655 Villeneuve d' Ascq (France); Coffinier, Yannick [Institut de Recherche Interdisciplinaire (IRI), FRE CNRS 2963, Institut d' lectronique, de Microelectronique et de Nanotechnologie (IEMN), UMR CNRS-8520, Cite Scientifique, Avenue Poincare, BP 60069, 59652 Villeneuve d' Ascq (France); Languille, Marie-Angelique [Unite de Catalyse et de Chimie du Solide, UCCS UMR CNRS-8181, Universite des Sciences et Technologies de Lille, Bat. C3, 59655 Villeneuve d' Ascq (France); Supiot, Philippe [Laboratoire de Genie des Procedes d' Interaction de Fluides Reactifs-Materiaux U.S.T.L., Cite Scientifique, 59655 Villeneuve d' Ascq (France); Boukherroub, Rabah [Institut de Recherche Interdisciplinaire (IRI), FRE CNRS 2963, Institut d' lectronique, de Microelectronique et de Nanotechnologie (IEMN), UMR CNRS-8520, Cite Scientifique, Avenue Poincare, BP 60069, 59652 Villeneuve d' Ascq (France)], E-mail: rabah.boukherroub@iemn.univ-lille1.fr

2008-04-20

The paper reports on the preparation and characterization of organosilicon thin polymer films deposited on glass slides coated with 5 nm adhesion layer of titanium and 50 nm of gold. The polymer was obtained by the decomposition of 1,1,3,3-tetramethyldisiloxane precursor (TMDSO) premixed with oxygen induced in a N{sub 2} plasma afterglow using remote plasma-enhanced chemical vapor deposition (PECVD) technique. The film thickness was controlled by laser interferometry and was 9 nm. The chemical stability of the gold substrate coated with the organosilicon polymer film (p-TMDSO) was studied in different acidic and basic solutions (pH 1-14). While the gold/polymer interface showed a high stability in acidic media, the film was almost completely removed in basic solutions. The resulting surfaces were characterized using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), water contact angle measurements, cyclic voltammetry, and surface plasmon resonance (SPR)

Preparation and characterization of thin organosilicon films deposited on SPR chip

International Nuclear Information System (INIS)

Szunerits, Sabine; Rich, Sami Abou; Coffinier, Yannick; Languille, Marie-Angelique; Supiot, Philippe; Boukherroub, Rabah

2008-01-01

The paper reports on the preparation and characterization of organosilicon thin polymer films deposited on glass slides coated with 5 nm adhesion layer of titanium and 50 nm of gold. The polymer was obtained by the decomposition of 1,1,3,3-tetramethyldisiloxane precursor (TMDSO) premixed with oxygen induced in a N 2 plasma afterglow using remote plasma-enhanced chemical vapor deposition (PECVD) technique. The film thickness was controlled by laser interferometry and was 9 nm. The chemical stability of the gold substrate coated with the organosilicon polymer film (p-TMDSO) was studied in different acidic and basic solutions (pH 1-14). While the gold/polymer interface showed a high stability in acidic media, the film was almost completely removed in basic solutions. The resulting surfaces were characterized using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), water contact angle measurements, cyclic voltammetry, and surface plasmon resonance (SPR)

Strategies for controlling acid rain: economic considerations

International Nuclear Information System (INIS)

Forster, B.A.; Crocker, T.D.

1992-01-01

There are two competing approaches to reducing pollution such as the acid rain precursors SOsub(2) and NOsub(x). In the command and control approach, pollution control legislation may dictate the technological method by which specified pollution reductions are to be achieved. A key feature of command-and-control regulations is their inflexibility. The alternative approach relies on market mechanisms and incentives to induce firms to reduce pollution voluntarily. Economists generally prefer this approach because it permits flexibility for firms in selecting abatement methods to minimize costs. This chapter deals with qualitative issues in determining and achieving an ''optimal'' pollution level using various taxes, subsidies or quantitative restrictions. Alternative permit schemes for achieving regional pollution control are considered. Statistical studies are discussed which compare the command-and-control approach with the economic incentives approach and show that there are substantial cost differences between them in most cases. Finally, some institutional factors, that may lead to more costly acid rain control schemes being selected, are examined. A list of 61 references is appended. (UK)

New insight into silica deposition in horsetail (Equisetum arvense

Directory of Open Access Journals (Sweden)

Exley Christopher

2011-07-01

Full Text Available Abstract Background The horsetails (Equisetum sp are known biosilicifiers though the mechanism underlying silica deposition in these plants remains largely unknown. Tissue extracts from horsetails grown hydroponically and also collected from the wild were acid-digested in a microwave oven and their silica 'skeletons' visualised using the fluor, PDMPO, and fluorescence microscopy. Results Silica deposits were observed in all plant regions from the rhizome through to the stem, leaf and spores. Numerous structures were silicified including cell walls, cell plates, plasmodesmata, and guard cells and stomata at varying stages of differentiation. All of the major sites of silica deposition in horsetail mimicked sites and structures where the hemicellulose, callose is known to be found and these serendipitous observations of the coincidence of silica and callose raised the possibility that callose might be templating silica deposition in horsetail. Hydroponic culture of horsetail in the absence of silicic acid resulted in normal healthy plants which, following acid digestion, showed no deposition of silica anywhere in their tissues. To test the hypothesis that callose might be templating silica deposition in horsetail commercially available callose was mixed with undersaturated and saturated solutions of silicic acid and the formation of silica was demonstrated by fluorimetry and fluorescence microscopy. Conclusions The initiation of silica formation by callose is the first example whereby any biomolecule has been shown to induce, as compared to catalyse, the formation of silica in an undersaturated solution of silicic acid. This novel discovery allowed us to speculate that callose and its associated biochemical machinery could be a missing link in our understanding of biosilicification.

Trends in the chemistry of atmospheric deposition and surface waters in the Lake Maggiore catchment

Directory of Open Access Journals (Sweden)

M. Rogora

2001-01-01

Full Text Available The Lake Maggiore catchment is the area of Italy most affected by acid deposition. Trend analysis was performed on long-term (15-30 years series of chemical analyses of atmospheric deposition, four small rivers draining forested catchments and four high mountain lakes. An improvement in the quality of atmospheric deposition was detected, due to decreasing sulphate concentration and increasing pH. Similar trends were also found in high mountain lakes and in small rivers. Atmospheric deposition, however, is still providing a large and steady flux of nitrogen compounds (nitrate and ammonium which is causing increasing nitrogen saturation in forest ecosystems and increasing nitrate levels in rivers. Besides atmospheric deposition, an important factor controlling water acidification and recovery is the weathering of rocks and soils which may be influenced by climate warming. A further factor is the episodic deposition of Saharan calcareous dust which contributes significantly to base cation deposition. Keywords: trend, atmospheric deposition, nitrogen, stream water chemistry.

Intelligent process control of fiber chemical vapor deposition

Science.gov (United States)

Jones, John Gregory

Chemical Vapor Deposition (CVD) is a widely used process for the application of thin films. In this case, CVD is being used to apply a thin film interface coating to single crystal monofilament sapphire (Alsb2Osb3) fibers for use in Ceramic Matrix Composites (CMC's). The hot-wall reactor operates at near atmospheric pressure which is maintained using a venturi pump system. Inert gas seals obviate the need for a sealed system. A liquid precursor delivery system has been implemented to provide precise stoichiometry control. Neural networks have been implemented to create real-time process description models trained using data generated based on a Navier-Stokes finite difference model of the process. Automation of the process to include full computer control and data logging capability is also presented. In situ sensors including a quadrupole mass spectrometer, thermocouples, laser scanner, and Raman spectrometer have been implemented to determine the gas phase reactants and coating quality. A fuzzy logic controller has been developed to regulate either the gas phase or the in situ temperature of the reactor using oxygen flow rate as an actuator. Scanning electron microscope (SEM) images of various samples are shown. A hierarchical control structure upon which the control structure is based is also presented.

Control Room Habitability for Accidental Sulfuric Acid Release

International Nuclear Information System (INIS)

Cho, Sungmin; Lee, Heedo; Song, Dongsoo

2006-01-01

The 10 CFR 50 Appendix A Criterion 19, 'Control Room', requires that a control room be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions. For compliance with the requirement, the control room of a nuclear power plant should be appropriately protected from hazardous chemicals that may be discharged as a result of equipment failures, operator errors, or events and conditions outside the control of the nuclear power plant. We have excluded sulfuric acid from a target of estimation for control room habitability merely because its boiling point is too high; qualitative analysis in this paper shows that we can exclude sulfuric acid from the target of habitability estimation

Controlled density of vertically aligned carbon nanotubes in a triode plasma chemical vapor deposition system

International Nuclear Information System (INIS)

Lim, Sung Hoon; Park, Kyu Chang; Moon, Jong Hyun; Yoon, Hyun Sik; Pribat, Didier; Bonnassieux, Yvan; Jang, Jin

2006-01-01

We report on the growth mechanism and density control of vertically aligned carbon nanotubes using a triode plasma enhanced chemical vapor deposition system. The deposition reactor was designed in order to allow the intermediate mesh electrode to be biased independently from the ground and power electrodes. The CNTs grown with a mesh bias of + 300 V show a density of ∼ 1.5 μm -2 and a height of ∼ 5 μm. However, CNTs do not grow when the mesh electrode is biased to - 300 V. The growth of CNTs can be controlled by the mesh electrode bias which in turn controls the plasma density and ion flux on the sample

Structurally controlled deposition of silicon onto nanowires

Science.gov (United States)

Wang, Weijie; Liu, Zuqin; Han, Song; Bornstein, Jonathan; Stefan, Constantin Ionel

2018-03-20

Provided herein are nanostructures for lithium ion battery electrodes and methods of fabrication. In some embodiments, a nanostructure template coated with a silicon coating is provided. The silicon coating may include a non-conformal, more porous layer and a conformal, denser layer on the non-conformal, more porous layer. In some embodiments, two different deposition processes, e.g., a PECVD layer to deposit the non-conformal layer and a thermal CVD process to deposit the conformal layer, are used. Anodes including the nanostructures have longer cycle lifetimes than anodes made using either a PECVD or thermal CVD method alone.

Improvement in Device Performance and Reliability of Organic Light-Emitting Diodes through Deposition Rate Control

Directory of Open Access Journals (Sweden)

Shun-Wei Liu

2014-01-01

Full Text Available We demonstrated a fabrication technique to reduce the driving voltage, increase the current efficiency, and extend the operating lifetime of an organic light-emitting diode (OLED by simply controlling the deposition rate of bis(10-hydroxybenzo[h]qinolinato beryllium (Bebq2 used as the emitting layer and the electron-transport layer. In our optimized device, 55 nm of Bebq2 was first deposited at a faster deposition rate of 1.3 nm/s, followed by the deposition of a thin Bebq2 (5 nm layer at a slower rate of 0.03 nm/s. The Bebq2 layer with the faster deposition rate exhibited higher photoluminescence efficiency and was suitable for use in light emission. The thin Bebq2 layer with the slower deposition rate was used to modify the interface between the Bebq2 and cathode and hence improve the injection efficiency and lower the driving voltage. The operating lifetime of such a two-step deposition OLED was 1.92 and 4.6 times longer than that of devices with a single deposition rate, that is, 1.3 and 0.03 nm/s cases, respectively.

Macro controlling of copper oxide deposition processes and spray mode by using home-made fully computerized spray pyrolysis system

Science.gov (United States)

Essa, Mohammed Sh.; Chiad, Bahaa T.; Shafeeq, Omer Sh.

2017-09-01

Thin Films of Copper Oxide (CuO) absorption layer have been deposited using home-made Fully Computerized Spray Pyrolysis Deposition system FCSPD on glass substrates, at the nozzle to substrate distance equal to 20,35 cm, and computerized spray mode (continues spray, macro-control spray). The substrate temperature has been kept at 450 °c with the optional user can enter temperature tolerance values ± 5 °C. Also that fixed molar concentration of 0.1 M, and 2D platform speed or deposition platform speed of 4mm/s. more than 1000 instruction program code, and specific design of graphical user interface GUI to fully control the deposition process and real-time monitoring and controlling the deposition temperature at every 200 ms. The changing in the temperature has been recorded during deposition processes, in addition to all deposition parameters. The films have been characterized to evaluate the thermal distribution over the X, Y movable hot plate, the structure and optical energy gap, thermal and temperature distribution exhibited a good and uniform distribution over 20 cm2 hot plate area, X-ray diffraction (XRD) measurement revealed that the films are polycrystalline in nature and can be assigned to monoclinic CuO structure. Optical band gap varies from 1.5-1.66 eV depending on deposition parameter.

Control of thermal deformation in dielectric mirrors using mechanical design and atomic layer deposition.

Science.gov (United States)

Gabriel, Nicholas T; Kim, Sangho S; Talghader, Joseph J

2009-07-01

A mechanical design technique for optical coatings that simultaneously controls thermal deformation and optical reflectivity is reported. The method requires measurement of the refractive index and thermal stress of single films prior to the design. Atomic layer deposition was used for deposition because of the high repeatability of the film constants. An Al2O3/HfO2 distributed Bragg reflector was deposited with a predicted peak reflectivity of 87.9% at 542.4 nm and predicted edge deformation of -360 nm/K on a 10 cm silicon substrate. The measured peak reflectivity was 85.7% at 541.7 nm with an edge deformation of -346 nm/K.

Treatment of acid drainage in uranium deposit by means of a natural wetland

International Nuclear Information System (INIS)

Grudeva, V.I.; Stoyanova, A.D.; Grudev, S.N.

2004-01-01

Acid drainage waters generated in the uranium deposit G-1, Western Bulgaria, were treated by means of a natural wetland located in the deposit. The waters had a pH in the range of about 2.4-3.9 and contained uranium and radium radionuclides, heavy metals (copper, zinc , cadmium, iron, manganese) arsenic and sulfates in concentrations usually much higher than the relevant permissible levels for waters intended for use in agriculture and/or industry. The wetland was characterized by abundant and emergent vegetation and a diverse microflora. Typha latifolia, Typha augustifolia and Potamogeton australis were the main plant species in the wetland but representatives of the genera Scirpus, Juncus, Elepchoris, Potamogeton, Carex and Poa as well as different algae were also present. The water flows through the wetland varied in the range at about 0.2-1,2 l/s reflecting water residence times in the wetland of about 10-50 hours. An efficient water cleanup took place in the wetland even during the cold winter months at ambient temperatures close to 0 o C. The removal of pollutants was due to different processes but the microbial dissimilatory sulphate reduction and the sorption of pollutants on organic matter (living and dead plant and microbial biomass) and clays present in the wetland played the main role. (author)

Reactive nitrogen deposition to South East Asian rainforest

Science.gov (United States)

di Marco, Chiara F.; Phillips, Gavin J.; Thomas, Rick; Tang, Sim; Nemitz, Eiko; Sutton, Mark A.; Fowler, David; Lim, Sei F.

2010-05-01

The supply of reactive nitrogen (N) to global terrestrial ecosystems has doubled since the 1960s as a consequence of human activities, such as fertilizer application and production of nitrogen oxides by fossil-fuel burning. The deposition of atmospheric N species constitutes a major nutrient input to the biosphere. Tropical forests have been undergoing a radical land use change by increasing cultivation of sugar cane and oil palms and the remaining forests are increasingly affected by anthropogenic activities. Yet, quantifications of atmospheric nitrogen deposition to tropical forests, and nitrogen cycling under near-pristine and polluted conditions are rare. The OP3 project ("Oxidant and Particle Photochemical Processes above a Southeast Asian Tropical Rainforest") was conceived to study how emissions of reactive trace gases from a tropical rain forest mediate the regional scale production and processing of oxidants and particles, and to better understand the impact of these processes on local, regional and global scale atmospheric composition, chemistry and climate. As part of this study we have measured reactive, nitrogen containing trace gas (ammonia, nitric acid) and the associated aerosol components (ammonium, nitrate) at monthly time resolution using a simple filter / denuder for 16 months. These measurements were made at the Bukit Atur Global Atmospheric Watch tower near Danum Valley in the Malaysian state of Sabah, Borneo. In addition, the same compounds were measured at hourly time-resolution during an intensive measurement period, with a combination of a wet-chemistry system based on denuders and steam jet aerosol collectors and an aerosol mass spectrometer (HR-ToF-AMS), providing additional information on the temporal controls. During this period, concentrations and fluxes of NO, NO2 and N2O were also measured. The measurements are used for inferential dry deposition modelling and combined with wet deposition data from the South East Asian Acid

Uranium deposit types and resources of Argentina

International Nuclear Information System (INIS)

Lopez, L.; Cuney, M.

2014-01-01

The uranium-related activities in Argentina begun in the 1950s and, as a result of the systematic exploration, several types of deposits have been discovered since then: volcanic and caldera-related, sandstone-hosted, vein spatially related to granite (intragranitic and perigranitic) and surficial. The deposits that have been the focus of the most important uranium exploitations are the ones that belong to the volcaniclastic type. These are localized in Permian formations associated with synsedimentary acid volcanism in the Sierra Pintada district (Mendoza province). The volcanic and caldera related type is also present in the Laguna Colorada deposit (Chubut province) located in the San Jorge basin (Cretaceous). Several important uranium mineralisations have been identified in Cretaceous fluvial sandstones and conglomerates, among which the most relevant is the Cerro Solo deposit (Chubut province) that corresponds to the paleochannel structure subtype. Other subtypes of sandstone model have been studied. For instance, the Don Otto deposit (Salta province), located in the Salta Group Basin (Cretaceous - Tertiary), belongs to the tabular U-V subtype. The roll front subtype can be also found in the Los Mogotes Colorados deposit (La Rioja province) which is hosted by Carboniferous continental sandstones. The uranium mineralisations in veins and disseminated episyenites within peraluminous leucogranites of the Sierras Pampeanas (Cordoba and San Luis provinces) represent other types of existing deposits. These granites are Devonian – Carboniferous and the related deposits are comparable to those from the Middle European Variscan. There are also other vein-type uranium deposits located in metamorphic basement in the periphery of high potassium calcalkaline granites (Sierras Pampeanas of Catamarca and La Rioja provinces), where the mineralisation control is mainly structural. The current uranium identified resources of the country are approximately 24,000 tU in the

Principal geological characteristics of the volcanic-type uranium deposits in China

International Nuclear Information System (INIS)

Fang Xiheng

2009-01-01

The volcanic-type uranium deposits in China distribute in two gigantic active belts, that is, circum-Pacific belt and latitudinal structure belt crossing Europe-Asia. The volcanic-type uranium deposits occur in continental volcanics,which are mainly composed of acid or alkali volcanics. Based on the study of 87 Sr/ 86 Sr initial ratio, REE distribution pattern and melt inclusion thermometry of volcanics, it is found that volcanic magma originated mainly from high-temperature melt of sialsphere and they were propably contaiminated partially by mantle materials. The volcanic eruption was controlled by regional fault and formed eruption belt, the beld can be divided into several sub-belt which was comprised by a serial eruption centres. The volcanic-type uranium deposits occur by the side of down-faulted red basin or associated with basic swarm. This means that the uranium mineralization is related to deep tectonics-magmatism. The paper proposes that the moderate erosion of volcanic belt is an important precondition to find uranium deposits. (authors)

Valproic acid reduces insulin-resistance, fat deposition and FOXO1-mediated gluconeogenesis in type-2 diabetic rat.

Science.gov (United States)

Khan, Sabbir; Kumar, Sandeep; Jena, Gopabandhu

2016-06-01

Recent evidences highlighted the role of histone deacetylases (HDACs) in insulin-resistance, gluconeogenesis and islet function. HDACs can modulate the expression of various genes, which directly or indirectly affect glucose metabolism. This study was aimed to evaluate the role of valproic acid (VPA) on fat deposition, insulin-resistance and gluconeogenesis in type-2 diabetic rat. Diabetes was developed in Sprague-Dawley rats by the combination of high-fat diet and low dose streptozotocin. VPA at the doses of 150 and 300 mg/kg/day and metformin (positive control) 150 mg/kg twice daily for 10 weeks were administered by oral gavage. Insulin-resistance, dyslipidemia and glycemia were evaluated by biochemical estimations, while fat accumulation and structural alteration were assessed by histopathology. Protein expression and insulin signaling were evaluated by western blot and immunohistochemistry. VPA treatment significantly reduced the plasma glucose, HbA1c, insulin-resistance, fat deposition in brown adipose tissue, white adipose tissue and liver, which are comparable to metformin treatment. Further, VPA inhibited the gluconeogenesis and glucagon expression as well as restored the histopathological alterations in pancreas and liver. Our findings provide new insights on the anti-diabetic role of VPA in type-2 diabetes mellitus by the modulation of insulin signaling and forkhead box protein O1 (FOXO1)-mediated gluconeogenesis. Since VPA is a well established clinical drug, the detailed molecular mechanisms of the present findings can be further investigated for possible clinical use. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

Electrophoretic Deposition of Gallium with High Deposition Rate

Directory of Open Access Journals (Sweden)

Hanfei Zhang

2014-12-01

Full Text Available In this work, electrophoretic deposition (EPD is reported to form gallium thin film with high deposition rate and low cost while avoiding the highly toxic chemicals typically used in electroplating. A maximum deposition rate of ~0.6 μm/min, almost one order of magnitude higher than the typical value reported for electroplating, is obtained when employing a set of proper deposition parameters. The thickness of the film is shown to increase with deposition time when sequential deposition is employed. The concentration of Mg(NO32, the charging salt, is also found to be a critical factor to control the deposition rate. Various gallium micropatterns are obtained by masking the substrate during the process, demonstrating process compatibility with microfabrication. The reported novel approach can potentially be employed in a broad range of applications with Ga as a raw material, including microelectronics, photovoltaic cells, and flexible liquid metal microelectrodes.

Photoelectrocatalytic degradation of oxalic acid by spray deposited nanocrystalline zinc oxide thin films

International Nuclear Information System (INIS)

Shinde, S.S.; Shinde, P.S.; Sapkal, R.T.; Oh, Y.W.; Haranath, D.; Bhosale, C.H.; Rajpure, K.Y.

2012-01-01

Highlights: ► Influence of substrate temperature onto the physico-chemical properties. ► Photochemical, structural, luminescent, optoelectrical and thermal properties. ► The kinetics of oxalic acid degradation with reaction mechanism. ► Extent of mineralization by COD and TOC. - Abstract: The high quality nano-crystalline zinc oxide thin films are deposited onto corning glasses by spray pyrolysis technique. The influence of reaction temperature onto their photoelectrochemical, structural, morphological, optoelectronic, luminescence and thermal properties has been investigated. The structural characteristics studied by X-ray diffractometry has complemented by resistivity measurements and UV–Vis spectroscopy. The photoelectrochemical activity shows enhancement in short circuit current (I sc = 0.357 mA) and open circuit voltage (V oc = 0.48 V). Direct band gap calculated by considering R and T values of ZnO thin films increases from 3.14–3.21 eV exhibiting a slight blue shift in band edge. Three characteristic luminescence peaks having near band-edge, blue and green emission are observed in the photoluminescence spectra. The specific heat and thermal conductivity study shows the phonon conduction behavior is dominant in films. Photocatalytic degradation of oxalic acid followed with reaction mechanism by using zinc oxide photoelectrode under solar illumination has been investigated.

Technological options for acid rain control

International Nuclear Information System (INIS)

Princiotta, F.T.; Sedman, C.B.

1993-01-01

The paper discusses technological options for acid rain control. Compliance with Title IV of the Clean Air Act Amendments of 1990 will require careful scrutiny of a number of issues before selecting control options to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions. One key consideration is the effect of fuel switching or control technology upon the existing dust collector, with additional air toxics legislation looming ahead. A number of likely SO2 and NOx retrofit technologies and estimated costs are presented, along with results of retrofit case studies. New hybrid particulate controls are also being developed to meet future requirements

1987 wet deposition temporal and spatial patterns in North America

Energy Technology Data Exchange (ETDEWEB)

Simpson, J.C.; Olsen, A.R.

1990-03-01

The focus of this report is on North American wet deposition temporal patterns from 1979 to 1987 and spatial patterns for 1987. The report investigates the patterns of annual precipitation-weighted average concentration and annual deposition for nine ion species: hydrogen, sulfate, nitrate, ammonium, calcium, chloride, sodium, potassium, and magnesium. Data are from the Acid Deposition System (ADS) for the statistical reporting of North American deposition data which includes the National Atmospheric Deposition Program/National Trends Network (NADP/NTN), the MAP3S precipitation chemistry network, the Utility Acid Precipitation Study Program (UAPSP), the Canadian Precipitation Monitoring Network (CAPMoN), and the daily and 4-weekly Acidic Precipitation in Ontario Study (APIOS-D and APIOS-C). Mosaic maps, based on surface estimation using kriging, display concentration and deposition spatial patterns of pH, hydrogen, sulfate, nitrate, ammonium, and calcium ion species for 1987 annual, winter, and summer periods. The temporal pattern analyses use a subset of 39 sites over a 9-year (1979--1987) period and an expanded subset of 140 sites with greater spatial coverage over a 6-year (1982--1987) period. 68 refs., 15 figs., 15 tabs.

Controlling the resistivity gradient in aluminum-doped zinc oxide grown by plasma-enhanced chemical vapor deposition

NARCIS (Netherlands)

Ponomarev, M.; Verheijen, M.A.; Keuning, W.; Sanden, van de M.C.M.; Creatore, M.

2012-01-01

Aluminum-doped ZnO (ZnO:Al) grown by chemical vapor deposition (CVD) generally exhibit a major drawback, i.e., a gradient in resistivity extending over a large range of film thickness. The present contribution addresses the plasma-enhanced CVD deposition of ZnO:Al layers by focusing on the control

Uranium deposits associated to tertiary acid volcanism of the Pena Blanca Sierra (Chihuahua, Mexico)

International Nuclear Information System (INIS)

Aniel, B.

1986-12-01

The uraniferous deposits located in the Sierra de Pena Blanca (Chihuahua, Mexico) are the consequence of successive events that modified acid volcanic rocks. The devitrification of the Nopal Formation, vitroclastic tuffs, is esential in the cooling history because it releases uranium that becomes available. The uranium present in fluids as uranylcarbonate complexes, precipitate along the lamellea of hematite (exsolutions of the ilmenites). The presence of sulfur causes the destabilization of the ilmenites with uranium oxide (pitchblende - titanium oxide - pyrite), the pseudomorph of magnetites (pitchblende - pyrite) and the transformation of hematite into pyrite. The silice coming from the kaolinization of feldspars recristallizes as microcristalline quartz so that the rock appears compact. Fractures cause the uplifting of the lower unit of Nopal formation. It has been altered to montmorillonite. A carbonatation of this tuff has been observed and these two types of alteration occur after kaolinization. The Escuadra formation overlies the Nopal formation. The deposition takes place on an eroded basement where a soil developed. The two formations will together undergo transformations due to the saturation level and the primary ore will be only oxidized or oxidized, transported and reconcentrated. Late and localized thermal activities have been observed and may be the result of tectonic movements occurring after the supergene modification [fr

Mechanisms of fat, oil and grease (FOG) deposit formation in sewer lines.

Science.gov (United States)

He, Xia; de los Reyes, Francis L; Leming, Michael L; Dean, Lisa O; Lappi, Simon E; Ducoste, Joel J

2013-09-01

FOG deposits in sewer systems have recently been shown to be metallic salts of fatty acids. However, the fate and transport of FOG deposit reactant constituents and the complex interactions during the FOG deposit formation process are still largely unknown. In this study, batch tests were performed to elucidate the mechanisms of FOG deposit formation that lead to sanitary sewer overflows (SSOs). We report the first formation of FOG deposits on a concrete surface under laboratory conditions that mimic the formation of deposits in sewer systems. Results showed that calcium, the dominant metal in FOG deposits, can be released from concrete surfaces under low pH conditions and contribute to the formation process. Small amounts of additional oil to grease interceptor effluent substantially facilitated the air/water or pipe surface/water interfacial reaction between free fatty acids and calcium to produce surface FOG deposits. Tests of different fatty acids revealed that more viscous FOG deposit solids were formed on concrete surfaces, and concrete corrosion was accelerated, in the presence of unsaturated FFAs versus saturated FFAs. Based on all the data, a comprehensive model was proposed for the mechanisms of FOG deposit formation in sewer systems. Copyright © 2013 Elsevier Ltd. All rights reserved.

Physicochemical aspects of decomposition of silica-alumina ores of argillites and green clays of Chashma-Sang Deposit of the Republic of Tajikistan by hydrochloric and nitric acids

International Nuclear Information System (INIS)

Kayumov, A.M.

2018-01-01

The purpose of work is to study the processes of decomposition of silica-alumina ores of argillites and green clays of Chashma-Sang Deposit of the Republic of Tajikistan by hydrochloric and nitric acids in temperature interval 20-98 deg C with the using of methods of selective extraction of valuable materials; elaboration of rational conditions of decomposition of raw material. Physicochemical properties of initial aluminium comprising ores, intermediate and final products of processing of argillites and green clays have been studied. Kinetic parameters of processes at acidic decomposition of argillites and green clays have been studied as well. The kinetic parameters of processes of decomposition of green clays and argillites by nitric and hydrochloric acids have been calculated. The flowsheet of complex processing of green clays and argillites of Chashma-Sang Deposit has been elaborated.

Sediment problems in reservoirs. Control of sediment deposits

Energy Technology Data Exchange (ETDEWEB)

Jacobsen, Tom

1997-12-31

When a reservoir is formed on a river, sediment will deposit in the reservoir. Such processes are unfortunate, for instance, for the implementation of hydroelectric energy. This thesis studies the problem of reservoir sedimentation and discusses methods of removing the sediments. Various aspects of reservoir sedimentation are discussed. Anthropogenic impacts seem to greatly affect the erosion processes. Temporal distribution is uneven, mainly because of the very large flood events. A world map showing the Reservoir Capacity: Annual Sediment Inflow ratio for reservoirs with volume equal to 10% of annual inflow has been prepared. The map shows that sedimentation is severe in the western parts of North and South America, eastern, southern and northern Africa, parts of Australia and most of Asia. The development of medium-sized reservoirs is difficult, as they are too large for conventional flushing technique and too small to store the sediment that accumulates during their economic lifetime. A computer model, SSIIM, was used with good results in a case study of two flood drawdown trials in Lake Roxburg, New Zealand. Two techniques have been developed that permits controlled suction of sediment and water into a pipe: the Slotted Pipe Sediment Sluicer (SPSS) and the Saxophone Sediment Sluicer (SSS). The techniques exploit the inflow pattern in through a slot in a pipe. An equation describing this inflow pattern was derived and verified experimentally. The SPSS is fixed near the reservoir bed, and sediment that deposits on top of it is removed in the sluicing process. The SSS sluices sediment from the surface of the sediment deposits. Some technical and economic conditions affecting the economics of sediment removal from reservoirs have been identified and studied. 79 refs., 112 figs., 14 tabs.

Rapid Deposition of Oxidized Biogenic Compounds to a Temperate Forest

Science.gov (United States)

Nguyen, Tran B.; Crounse, John D.; Teng, Alex P.; St. Clair, Jason M.; Paulot, Fabien; Wolfe, Glenn M.; Wennberg, Paul O.

2015-01-01

We report fluxes and dry deposition velocities for 16 atmospheric compounds above a southeastern United States forest, including: hydrogen peroxide (H2O2), nitric acid (HNO3), hydrogen cyanide (HCN), hydroxymethyl hydroperoxide, peroxyacetic acid, organic hydroxy nitrates, and other multifunctional species derived from the oxidation of isoprene and monoterpenes. The data suggest that dry deposition is the dominant daytime sink for small, saturated oxygenates. Greater than 6 wt %C emitted as isoprene by the forest was returned by dry deposition of its oxidized products. Peroxides account for a large fraction of the oxidant flux, possibly eclipsing ozone in more pristine regions. The measured organic nitrates comprise a sizable portion (15%) of the oxidized nitrogen input into the canopy, with HNO3 making up the balance. We observe that water-soluble compounds (e.g., strong acids and hydroperoxides) deposit with low surface resistance whereas compounds with moderate solubility (e.g., organic nitrates and hydroxycarbonyls) or poor solubility (e.g., HCN) exhibited reduced uptake at the surface of plants. To first order, the relative deposition velocities of water-soluble compounds are constrained by their molecular diffusivity. From resistance modeling, we infer a substantial emission flux of formic acid at the canopy level (approx. 1 nmol m(exp.-2)·s(exp.-1)). GEOS-Chem, awidely used atmospheric chemical transport model, currently underestimates dry deposition for most molecules studied in this work. Reconciling GEOS-Chem deposition velocities with observations resulted in up to a 45% decrease in the simulated surface concentration of trace gases.

Air pollution: Tropospheric ozone, and wet deposition of sulfate and inorganic nitrogen

Science.gov (United States)

John W. Coulston

2009-01-01

The influence of air pollutants on ecosystems in the United States is an important environmental issue. The term “air pollution” encompasses a wide range of topics, but acid deposition and ozone are primary concerns in the context of forest health. Acid deposition partially results from emissions of sulfur dioxide, nitrogen oxides, and ammonia that are deposited in wet...

Low temperature (< 100 °C) deposited P-type cuprous oxide thin films: Importance of controlled oxygen and deposition energy

International Nuclear Information System (INIS)

Li, Flora M.; Waddingham, Rob; Milne, William I.; Flewitt, Andrew J.; Speakman, Stuart; Dutson, James; Wakeham, Steve; Thwaites, Mike

2011-01-01

With the emergence of transparent electronics, there has been considerable advancement in n-type transparent semiconducting oxide (TSO) materials, such as ZnO, InGaZnO, and InSnO. Comparatively, the availability of p-type TSO materials is more scarce and the available materials are less mature. The development of p-type semiconductors is one of the key technologies needed to push transparent electronics and systems to the next frontier, particularly for implementing p–n junctions for solar cells and p-type transistors for complementary logic/circuits applications. Cuprous oxide (Cu 2 O) is one of the most promising candidates for p-type TSO materials. This paper reports the deposition of Cu 2 O thin films without substrate heating using a high deposition rate reactive sputtering technique, called high target utilisation sputtering (HiTUS). This technique allows independent control of the remote plasma density and the ion energy, thus providing finer control of the film properties and microstructure as well as reducing film stress. The effect of deposition parameters, including oxygen flow rate, plasma power and target power, on the properties of Cu 2 O films are reported. It is known from previously published work that the formation of pure Cu 2 O film is often difficult, due to the more ready formation or co-formation of cupric oxide (CuO). From our investigation, we established two key concurrent criteria needed for attaining Cu 2 O thin films (as opposed to CuO or mixed phase CuO/Cu 2 O films). First, the oxygen flow rate must be kept low to avoid over-oxidation of Cu 2 O to CuO and to ensure a non-oxidised/non-poisoned metallic copper target in the reactive sputtering environment. Secondly, the energy of the sputtered copper species must be kept low as higher reaction energy tends to favour the formation of CuO. The unique design of the HiTUS system enables the provision of a high density of low energy sputtered copper radicals/ions, and when combined with a

Inter- and intra-annual chemical variability during the ice-free season in lakes with different flushing rates and acid deposition histories.

Science.gov (United States)

Arnott, Shelley E; Dillon, Peter J; Somers, Keith; Keller, Bill

2003-01-01

Quantifying chemical variability in different lake types is important for the assessment of both chemical and biological responses to environmental change. For monitoring programs that emphasize a large number of lakes at the expense of frequent samples, high variability may influence how representative single samples are of the average conditions of individual lakes. Intensive temporal data from long-term research sites provide a unique opportunity to assess chemical variability in lakes with different characteristics. We compared the intra- and inter-annual variability of four acidification related variables (Gran alkalinity, pH, sulphate concentration, and total base cation concentration) in four lakes with different flushing rates and acid deposition histories. Variability was highest in lakes with high flushing rates and was not influenced by historic acid deposition in our study lakes. This has implications for the amount of effort required in monitoring programs. Lakes with high flushing rates will require more frequent sampling intervals than lakes with low flushing rates. Consideration of specific lake types should be included in the design of monitoring programs.

Advanced zirconia-coated carbonyl-iron particles for acidic magnetorheological finishing of chemical-vapor-deposited ZnS and other IR materials

Science.gov (United States)

Salzman, S.; Giannechini, L. J.; Romanofsky, H. J.; Golini, N.; Taylor, B.; Jacobs, S. D.; Lambropoulos, J. C.

2015-10-01

We present a modified version of zirconia-coated carbonyl-iron (CI) particles that were invented at the University of Rochester in 2008. The amount of zirconia on the coating is increased to further protect the iron particles from corrosion when introduced to an acidic environment. Five low-pH, magnetorheological (MR) fluids were made with five acids: acetic, hydrochloric, nitric, phosphoric, and hydrofluoric. All fluids were based on the modified zirconia-coated CI particles. Off-line viscosity and pH stability were measured for all acidic MR fluids to determine the ideal fluid composition for acidic MR finishing of chemical-vapor-deposited (CVD) zinc sulfide (ZnS) and other infrared (IR) optical materials, such as hot-isostatic-pressed (HIP) ZnS, CVD zinc selenide (ZnSe), and magnesium fluoride (MgF2). Results show significant reduction in surface artifacts (millimeter-size, pebble-like structures on the finished surface) for several standard-grade CVD ZnS substrates and good surface roughness for the non-CVD MgF2 substrate when MR finished with our advanced acidic MR fluid.

Chemical and mineralogical changes of waste and tailings from the Murgul Cu deposit (Artvin, NE Turkey): implications for occurrence of acid mine drainage.

Science.gov (United States)

Sağlam, Emine Selva; Akçay, Miğraç

2016-04-01

Being one of the largest copper-producing resources in Turkey, the Murgul deposit has been a source of environmental pollution for very long time. Operated through four open pits with an annual production of about 3 million tons of ore at an average grade of about 0.5% Cu, the deposit to date has produced an enormous pile of waste (exceeding 100 million tons) with tailings composed of 36 % SiO2, 39% Fe2O3 and 32% S, mainly in the form of pyrite and quartz. Waters in the vicinity of the deposit vary from high acid-acid (2.71-3.85) and high-extremely metal rich (34.48-348.12 mg/l in total) in the open pits to near neutral (6.51-7.83) and low metal (14.39-973.52 μg/l in total) in downstream environments. Despite low metal contents and near neutral pH levels of the latter, their suspended particle loads are extremely high and composed mainly of quartz and clay minerals with highly elevated levels of Fe (3.5 to 24.5% Fe2O3; 11% on average) and S (0.5 to 20.6% S; 7% on average), showing that Fe is mainly in the form of pyrite and lesser hematite. They also contain high concentrations of As, Au, Ba, Cu, Pb, and Zn. Waters collected along the course of polluted drainages are supersaturated with respect to Fe phases such as goethite, hematite, maghemite, magnetite, schwertmannite and ferrihydrite. Secondary phases such as Fe-sulphates are only found near the pits, but not along the streams due to neutral pH conditions, where pebbles are covered and cemented by Fe-oxides and hydroxides indicating that oxidation of pyrite has taken place especially at times of low water load. It follows, then, that the pyrite-rich sediment load of streams fed by the waste of the Murgul deposit is currently a big threat to the aquatic life and environment and will continue to be so even after the closure of the deposit. In fact, the oxidation will be enhanced and acidity increased due to natural conditions, which necessitates strong remedial actions to be taken.

Effects and quantification of acid runoff from sulfide-bearing rock deposited during construction of Highway E18, Norway

Science.gov (United States)

Hindar, Atle; Nordstrom, D. Kirk

2015-01-01

The Highway E18 between the cities of Grimstad and Kristiansand, southern Norway, constructed in the period 2006–2009, cuts through sulfide-bearing rock. The geology of this area is dominated by slowly-weathering gneiss and granites, and oxidation of fresh rock surfaces can result in acidification of surface water. Sulfide-containing rock waste from excavations during construction work was therefore deposited in three waste rock deposits off-site. The deposits consist of 630,000–2,360,000 metric tons of waste rock material. Shell sand and limestone gravel were added in layers in adequate amounts to mitigate initial acid runoff in one of the deposits. The shell sand addition was not adequate in the two others. The pH in the effluents from these two was reduced from 4.9–6.5 to 4.0–4.6, and Al concentrations increased from below 0.4 mg/L to 10–20 mg/L. Stream concentrations of trace metals increased by a factor of 25–400, highest for Ni, and then in decreasing order for Co, Mn, Cd, Zn and Cu. Concentrations of As, Cr and Fe remained unchanged. Ratios of Co/Ni and Cd/Zn indicate that the metal sources for these pair of metals are sphalerite and pyrite, respectively. Based on surveys and established critical limits for Al, surface waters downstream became toxic to fish and invertebrates. The sulfur release rates were remarkably stable in the monitoring period at all three sites. Annual sulfur release was 0.1–0.4% of the total amount of sulfur in the deposit, indicating release periods of 250–800 years. Precipitates of Al-hydroxysulfates, well-known from mining sites, were found at the base of the deposits, in streams and also along the ocean shore-line. The effects of added neutralization agents in the deposits and in treatment areas downstream gradually decreased, as indicated by reduced stream pH over time. Active measures are needed to avoid harmful ecological effects in the future.

Multi-material poly(lactic acid) scaffold fabricated via fused deposition modeling and direct hydroxyapatite injection as spacers in laminoplasty

Science.gov (United States)

Syuhada, Ghifari; Ramahdita, Ghiska; Rahyussalim, A. J.; Whulanza, Yudan

2018-02-01

Nowadays, additive manufacturing method has been used extensively to realize any product with specific attributes rather than the conventional subtractive manufacturing method. For instance, the additive manufacturing has enable us to construct a product layer-by-layer by successively depositing several materials in one session and one platform. This paper studied the properties of a 3D printed scaffold fabricated through Poly(Lactic-acid) (PLA) deposition modelling in combination with injectable hydroxyapatite (HA)/alginate as cell carrier. The scaffold was designed to serve as a spacer in cervical laminoplasty. Therefore, a series of test were conducted to elaborate the mechanical property, porosity and in-vitro toxicity testing. The results showed that the method is reliable to fabricate the scaffold as desired although the toxicity test needs more confirmation.

Modeling and control of diffusion and low-pressure chemical vapor deposition furnaces

Science.gov (United States)

De Waard, H.; De Koning, W. L.

1990-03-01

In this paper a study is made of the heat transfer inside cylindrical resistance diffusion and low-pressure chemical vapor deposition furnaces, aimed at developing an improved temperature controller. A model of the thermal behavior is derived which also covers the important class of furnaces equipped with semitransparent quartz process tubes. The model takes into account the thermal behavior of the thermocouples. It is shown that currently used temperature controllers are highly inefficient for very large scale integration applications. Based on the model an alternative temperature controller of the linear-quadratic-Gaussian type is proposed which features direct wafer temperature control. Some simulation results are given.

Quantification of Gaseous Elemental Mercury Dry Deposition to Environmental Surfaces using Mercury Stable Isotopes in a Controlled Environment

Science.gov (United States)

Rutter, A. P.; Schauer, J. J.; Shafer, M. M.; Olson, M.; Robinson, M.; Vanderveer, P.; Creswell, J. E.; Parman, A.; Mallek, J.; Gorski, P.

2009-12-01

Andrew P. Rutter (1) * *, James J, Schauer (1,2) *, Martin M. Shafer(1,2), Michael R. Olson (1), Michael Robinson (1), Peter Vanderveer (3), Joel Creswell (1), Justin L. Mallek (1), Andrew M. Parman (1) (1) Environmental Chemistry and Technology Program, 660 N. Park St, Madison, WI 53705. (2) Wisconsin State Laboratory of Hygiene, 2601 Agriculture Drive, Madison, WI 53718. (3) Biotron, University of Wisconsin - Madison, 2115 Observatory Drive, Madison, WI 53706 * Correspond author(jjschauer@wisc.edu) * *Presenting author (aprutter@wisc.edu) Abstract Gaseous elemental mercury (GEM) is the predominant component of atmospheric mercury outside of arctic depletion events, and locations where anthropogenic point sources are not influencing atmospheric concentrations. GEM constitutes greater than 99% of the mercury mass in most rural and remote locations. While dry and wet deposition of atmospheric mercury is thought to be dominated by oxidized mercury (a.k.a. reactive mercury), only small GEM uptake to environmental surfaces could impact the input of mercury to terrestrial and aquatic ecosystems. Dry deposition and subsequent re-emission of gaseous elemental mercury is a pathway from the atmosphere that remains only partially understood from a mechanistic perspective. In order to properly model GEM dry deposition and re-emission an understanding of its dependence on irradiance, temperature, and relative humidity must be measured and parameterized for a broad spectrum of environmental surfaces colocated with surrogate deposition surfaces used to make field based dry deposition measurements. Measurements of isotopically enriched GEM dry deposition were made with a variety of environmental surfaces in a controlled environment room at the University of Wisconsin Biotron. The experimental set up allowed dry deposition components which are not easily separated in the field to be decoupled. We were able to isolate surface transfer processes from variabilities caused by

Sensing system for detection and control of deposition on pendant tubes in recovery and power boilers

Science.gov (United States)

Kychakoff, George [Maple Valley, WA; Afromowitz, Martin A [Mercer Island, WA; Hogle, Richard E [Olympia, WA

2008-10-14

A system for detection and control of deposition on pendant tubes in recovery and power boilers includes one or more deposit monitoring sensors operating in infrared regions of about 4 or 8.7 microns and directly producing images of the interior of the boiler, or producing feeding signals to a data processing system for information to enable a distributed control system by which the boilers are operated to operate said boilers more efficiently. The data processing system includes an image pre-processing circuit in which a 2-D image formed by the video data input is captured, and includes a low pass filter for performing noise filtering of said video input. It also includes an image compensation system for array compensation to correct for pixel variation and dead cells, etc., and for correcting geometric distortion. An image segmentation module receives a cleaned image from the image pre-processing circuit for separating the image of the recovery boiler interior into background, pendant tubes, and deposition. It also accomplishes thresholding/clustering on gray scale/texture and makes morphological transforms to smooth regions, and identifies regions by connected components. An image-understanding unit receives a segmented image sent from the image segmentation module and matches derived regions to a 3-D model of said boiler. It derives a 3-D structure the deposition on pendant tubes in the boiler and provides the information about deposits to the plant distributed control system for more efficient operation of the plant pendant tube cleaning and operating systems.

The Coupling Effect Research of Ash Deposition and Condensation in Low Temperature Flue Gas

Directory of Open Access Journals (Sweden)

Lei Ma

2016-01-01

Full Text Available Ash deposition is a key factor that deteriorates the heat transfer performance and leads to higher energy consumption of low pressure economizer working in low temperature flue gas. In order to study the ash deposition of heat exchange tubes in low temperature flue gas, two experiments are carried out with different types of heat exchange tubes in different flue gas environments. In this paper, Nusselt Number Nu and fouling factor ε are calculated to describe the heat transfer characteristics so as to study the ash deposition condition. The scanning electron microscope (SEM is used for the analysis of ash samples obtained from the outer wall of heat exchange tubes. The dynamic process of ash deposition is studied under different temperatures of outer wall. The results showed that ash deposition of heat exchanger will achieve a stable state in constant flue gas environment. According to the condition of condensation of acid vapor and water vapor, the process of ash deposition can be distinguished as mere ash deposition, acid-ash coupling deposition, and acid-water-ash coupling deposition.

Control of hydrocarbon radicals and film deposition by using an RF Whistler wave discharge

International Nuclear Information System (INIS)

Mieno, Tetsu; Shoji, Tatsuo; Kadota, Kiyoshi.

1991-10-01

Production of hydrocarbon radicals is controlled by using an RF Whistler wave discharge in a low pressure region (∼0.1 Pa). Plasma density of 10 10 - 10 13 cm -3 , electron temperature of 2-20 eV is obtained for the discharge of admixture of Ar and small content of source gases (CH 4 , C 2 H 2 , CO). Spectroscopic measurement indicates that densities of CH and H radicals and deposition rate of amorphous carbon:H film increase with electron density, electron temperature and source gas pressure. The etching effect of H atoms influences on the deposition rate and a high deposition rate (90 μm/hr for CO/Ar discharge) is obtained even in a low neutral pressure discharge. (author)

Microstructural control during direct laser deposition of a β-titanium alloy

International Nuclear Information System (INIS)

Qiu, Chunlei; Ravi, G.A.; Attallah, Moataz M.

2015-01-01

Graphical abstract: Microstructural development of Ti5553 during Direct Laser Deposition (DLD). - Highlights: • Good structural and geometrical integrity could be achieved by process design. • Build height increases with decreased scanning speed and increased powder flow rate. • Keeping Z increment close to actual layer thickness is crucial for consistent building. • The laser deposited Ti5553 are dominated by mixed columnar and equiaxed grains. • In situ dwelling and annealing promote α precipitation which improves microhardness. - Abstract: A concern associated with Direct Laser Deposition (DLD) is the difficulty in controlling microstructure due to rapid cooling rates after deposition, particularly in beta-Ti alloys. In these alloys, the beta-phase is likely to exist following DLD, instead of the desirable duplex alpha + beta microstructure that gives a good balance of properties. Thus, in this work, a parametric study was performed to assess the role of DLD parameters on porosity, build geometry, and microstructure in a beta-Ti alloy, Ti–5Al–5Mo–5V–3Cr (Ti5553). The builds were examined using optical microscopy, scanning electron microscopy, and X-ray diffraction. Microhardness measurements were performed to assess the degree of re-precipitation of alpha-phase following an in situ dwelling and laser annealing procedure. The study identified several processing conditions that enable deposition of samples with the desired geometry and low porosity level. The microstructure was dominated by beta-phase, except for the region near the substrate where a limited amount of alpha-precipitates was present due to reheating effect. Although the microstructure was a mixture of equiaxed and columnar beta-grains alongside infrequent fine alpha-precipitates, the builds showed fairly uniform microhardness in different regions. In situ dwelling and annealing did not cause an obvious change in porosity, but did promote the formation of alpha-precipitates

Spatial control of direct chemical vapor deposition of graphene on silicon dioxide by directional copper dewetting

NARCIS (Netherlands)

van den Beld, Wesley Theodorus Eduardus; van den Berg, Albert; Eijkel, Jan C.T.

2016-01-01

In this paper we present a method for the spatial control of direct graphene synthesis onto silicon dioxide by controlled dewetting. The dewetting process is controlled through a combination of using a grooved substrate and conducting copper deposition at an angle. The substrate is then treated

Electronic-state control of amino acids on semiconductor surfaces

International Nuclear Information System (INIS)

Oda, Masato; Nakayama, Takashi

2005-01-01

Electronic structures of amino acids on the Si(1 1 1) surfaces are investigated by using ab initio Hartree-Fock calculations. It is shown that among various polar amino acids, a histidine is the only one that can be positively ionized when hole carriers are supplied in the Si substrate, by transferring the hole charge from Si substrate to an amino acid. This result indicates that the ionization of a histidine, which will activate the protein functions, can be controlled electrically by producing amino acid/Si junctions

Biological low pH Mn(II) oxidation in a manganese deposit influenced by metal-rich groundwater

Science.gov (United States)

Bohu, Tsing; Akob, Denise M.; Abratis, Michael; Lazar, Cassandre S.; Küsel, Kirsten

2016-01-01

The mechanisms, key organisms, and geochemical significance of biological low-pH Mn(II) oxidation are largely unexplored. Here, we investigated the structure of indigenous Mn(II)-oxidizing microbial communities in a secondary subsurface Mn oxide deposit influenced by acidic (pH 4.8) metal-rich groundwater in a former uranium mining area. Microbial diversity was highest in the Mn deposit compared to the adjacent soil layers and included the majority of known Mn(II)-oxidizing bacteria (MOB) and two genera of known Mn(II)-oxidizing fungi (MOF). Electron X-ray microanalysis showed that romanechite [(Ba,H2O)2(Mn4+,Mn3+)5O10] was conspicuously enriched in the deposit. Canonical correspondence analysis revealed that certain fungal, bacterial, and archaeal groups were firmly associated with the autochthonous Mn oxides. Eight MOB within the Proteobacteria, Actinobacteria, and Bacteroidetes and one MOF strain belonging to Ascomycota were isolated at pH 5.5 or 7.2 from the acidic Mn deposit. Soil-groundwater microcosms demonstrated 2.5-fold-faster Mn(II) depletion in the Mn deposit than adjacent soil layers. No depletion was observed in the abiotic controls, suggesting that biological contribution is the main driver for Mn(II) oxidation at low pH. The composition and species specificity of the native low-pH Mn(II) oxidizers were highly adapted to in situ conditions, and these organisms may play a central role in the fundamental biogeochemical processes (e.g., metal natural attenuation) occurring in the acidic, oligotrophic, and metalliferous subsoil ecosystems.

Characterization of chemically deposited low-cost 2-6 thin films solar cells : modifying effects with catalytic silicotungstic acid (STA)

Energy Technology Data Exchange (ETDEWEB)

Petuenju, E.N.; Savadogo, O. [Ecole Polytechnique de Montreal, Montreal, PQ (Canada). Laboratoire de nouveaux materiaux pour l' energie et l' electrochimie

2008-07-01

This paper described some properties of cadmium sulphide (CdS) thin films that were chemically deposited on a silicon wafer for solar cell and optoelectronic applications. The as-deposited films were thermally annealed and characterized through structural, electrical, optical, and spectroscopic methods. The modifying effects of silicotungstic acid (STA) showed promising characteristics for various applications, including X- and gamma-ray detector devices. The films were characterized by X-rays Photoelectron Spectroscopy, Scanning Electron Microscopy, X-ray Diffraction, and Photoluminescence. Ellipsometry measurements were used to determine the thickness of the sample. The study showed that there is no significant effect of the addition of 10-4 M of STA on the thickness of the film. This might be due to the low concentration of STA. No significant difference was noted for samples deposited with and without STA. In both cases the crystallite size of the sample was estimated to be lower than 1.5 microns. The CdS/Si and CdS(STA)/Si samples were annealed at 360 degrees C for 12 hours. The samples prepared with and without STA had the same structure. CdS deposited without and STA exhibited a mixed hexagonal and cubic structure, most likely because the annealing temperature of the sample was very close to the transition temperature of the cubic structure to the hexagonal structure. 3 refs., 1 tab., 3 figs.

Electrostatic Deposition of Large-Surface Graphene

Directory of Open Access Journals (Sweden)

Charles Trudeau

2018-01-01

Full Text Available This work describes a method for electrostatic deposition of graphene over a large area using controlled electrostatic exfoliation from a Highly Ordered Pyrolytic Graphite (HOPG block. Deposition over 130 × 130 µm2 with 96% coverage is achieved, which contrasts with sporadic micro-scale depositions of graphene with little control from previous works on electrostatic deposition. The deposition results are studied by Raman micro-spectroscopy and hyperspectral analysis using large fields of view to allow for the characterization of the whole deposition area. Results confirm that laser pre-patterning of the HOPG block prior to cleaving generates anchor points favoring a more homogeneous and defect-free HOPG surface, yielding larger and more uniform graphene depositions. We also demonstrate that a second patterning of the HOPG block just before exfoliation can yield features with precisely controlled geometries.

Direct fabrication of integrated 3D Au nanobox arrays by sidewall deposition with controllable heights and thicknesses

Energy Technology Data Exchange (ETDEWEB)

Cha, Nam-Goo; Lee, Bong Kuk; Kanki, Teruo; Lee, Hea Yeon; Kawai, Tomoji; Tanaka, Hidekazu, E-mail: h-tanaka@sanken.osaka-u.ac.j [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

2009-09-30

This paper provides a unique strategy for controlling integrated hollow nanostructure arrays such as boxes or pillars at the nanometer scale. The key merit of this technique is that it can overcome resolution limits by sidewall deposition and deposit various materials using a sputtering method. The sputtering method can be replaced by other dry deposition techniques such as pulsed laser deposition (PLD) for complex functional materials. Furthermore, it can produce low-cost large-area fabrication and high reproducibility using the NIL (nanoimprint lithograph) process. The fabrication method consists of a sequence of bilayer spin-coating, UV-NIL, RIE (reactive ion etching), sputtering, ion milling and piranha cleaning processes. By changing the deposition time and molds, various thicknesses and shapes can be fabricated, respectively. Furthermore, the fabricated Au box nanostructure has a bending zone of the top layer and a {approx}17 nm undercut of the bottom layer as observed by SEM (scanning electron microscope). The sidewall thickness was changed from 12 to 61 nm by controlling the deposition time, and was investigated to understand the relationship with blanket thicknesses and geometric effects. The calculated sidewall thickness matched well with experimental results. Using smaller hole-patterned molds, integrated nanobox arrays, with inner squares measuring {approx}160 nm, and nanopillar arrays, with inside pores measuring {approx}65 nm, were fabricated under the same conditions.

Structural and surface morphological studies of long chain fatty acid thin films deposited by Langmuir-Blodgett technique

Energy Technology Data Exchange (ETDEWEB)

Das, Nayan Mani, E-mail: nayanmanidas3@gmail.com [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Roy, Dhrubojyoti [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India); Gupta, Mukul [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India); Gupta, P.S. [Department of Applied Physics, Indian School of Mines, Dhanbad 826004 (India)

2012-12-15

In the present work we aim to study the structural and surface morphological characteristics of divalent cation (cadmium ion, Cd{sup 2+}) induced thin mono- to multilayer films of fatty acids such as arachidic acid and stearic acid prepared by the Langmuir-Blodgett (LB) technique. These ultra thin films of various numbers of layers were studied by X-ray diffraction (XRD), X-ray reflectivity (XRR) and Atomic Force Microscopy (AFM). In this specific Y-type deposition, it was found that as the individual layer thickness increases, the corresponding layer by layer interfacial electron density of the thin films decreases. Since the fatty acid chain tries to maintain its minimum value of cross-sectional area, tilting occurs with respect to its nearest neighbor. The tilt angle calculated for 9 layers of cadmium arachidate (CdA{sub 2}) and cadmium stearate (CdSt{sub 2}) are 18 Degree-Sign and 19.5 Degree-Sign , respectively. An asymmetric air gap of thickness {approx}3 A was also seen between the tail parts of 2 molecular chains. The RMS roughness and average height factors calculated through AFM studies show non-uniform surface morphology of both CdA{sub 2} and CdSt{sub 2}, although the calculated topographic variations were found to have more irregularity in case of CdSt{sub 2} than in case of CdA{sub 2}.

Characterisation of boric acid aerosol behaviour and interactions with stainless steel

International Nuclear Information System (INIS)

Anderson, A.B.; Beard, A.M.; Bennett, P.J.; Benson, C.G.

1991-03-01

Experiments have been conducted to determine the physical characteristics of boric acid aerosol. Aqueous solutions of boric acid (either 200 or 2000 ppm boron) were injected at a controlled rate onto a 304 stainless steel cone held at 1000 o C. The transport and deposition of the resulting aerosol was studied through a system including pipework and a dilution chamber. Work was also undertaken to characterise the interaction between boric acid and stainless steel. Boric acid was vaporized in steam-argon atmospheres at 300 o C and passed over 304 stainless steel coupons held at temperatures between 400 and 1000 o C. (author)

Feedback control of the lower hybrid power deposition profile on Tore Supra

International Nuclear Information System (INIS)

Barana, O; Mazon, D; Laborde, L; Turco, F

2007-01-01

The Tore Supra facility is well suited to study ITER relevant topics such as the real-time control of plasma current and the sustaining of steady-state discharges. This work describes a tool that was recently developed and implemented on Tore Supra to control in real time, by means of the direct knowledge of the suprathermal electron local emission profile, the width of the lower hybrid power deposition profile. This quantity can be considered to some extent equivalent to the width of the plasma current density profile in case of fully non-inductive discharges. This system takes advantage of an accurate hard x-ray diagnostics, of an efficient lower hybrid additional heating and of a reliable real-time communication network. The successful experiments carried out to test the system employed, as actuators, the parallel refractive index n // and the total power P LH . The control of the suprathermal electron local emission profile through n // was also integrated with the feedback control of the total plasma current I P with P LH and of the loop voltage V loop with the central solenoid flux. These results demonstrate that the system is robust, reliable and able to counterbalance destabilizing events. This tool can be effectively used in the future in fully non-inductive discharges to improve the MHD stability and to maintain internal transport barriers or lower hybrid enhanced performance modes. The real-time control of the lower hybrid power deposition profile could also be used in conjunction with the electron-cyclotron radiofrequency heating for synergy studies

Technologies for the control of fat and lean deposition in livestock.

Science.gov (United States)

Sillence, M N

2004-05-01

by the poor level of control over gene expression, and faces an uphill battle over consumer acceptance. There are several alternatives to HGPs and transgenics, that are more likely to gain world-wide acceptance. Genetic selection can be enhanced by using markers for polymorphic genes that control fat and lean, such as thyroglobulin, or the callipyge gene. Feed additives of natural origin, such as betaine, chromium and conjugated linoleic acid, can improve the fat:lean ratio under specific circumstances. Additionally, 'production vaccines' have been developed, which alter the neuro-endocrine system by causing an auto-immune response. Thus, antibodies have been used to neutralise growth-limiting factors, prolong the half-life of anabolic hormones, or activate hormone receptors directly. Unfortunately, none of these technologies is sufficiently well advanced yet to rival the use of exogenous HGPs in terms of efficacy and reliability. Therefore, further research is needed to find ways to control fat and lean deposition with due consideration of industry needs, animal welfare and consumer requirements.

Acid rain attack on outdoor sculpture in perspective

Science.gov (United States)

Livingston, Richard A.

2016-12-01

A major concern motivating research in acid rain materials effects has been the potential for damage to cultural heritage, particularly outdoor marble and bronze sculpture. However, a combination of field and laboratory studies has failed to show a correlation between rain pH and loss of materials. In order to understand this counterintuitive lack of acid rain effect, an aqueous geochemical modeling approach was used to analyze rain runoff chemistry for the relative importance of acid rain neutralization, dry deposition, and in the case of marble, natural carbonate dissolution. This approach involved the development of pH - SO42- phase diagrams for marble (calcium carbonate) and bronze (copper) under ambient environmental conditions. This then enabled reaction path modeling of the acid neutralization process using the pH range typically found in wet deposition (3.5-6). The results were for marble that the theoretical maximum amount of Ca2+ ion that could be lost due acid rain neutralization would be 0.158 mmol/l compared to 10.5 mmol/l by dry deposition, and for bronze, the Cu2+ ion losses would be 0.21 mmol/l and 47.3 mmol/l respectively. Consequently dry deposition effects on these materials have the potential to dominate over wet deposition effects. To test these predictions the geochemical models were applied to examples of data sets from mass balance (runoff vs rainfall) studies on a marble statue in New York City and some bronze memorial plaques at Gettysburg PA. Although these data sets were collected in the early 1980s they remain valid for demonstrating the mass balance method. For the marble statue, the mean Ca2+ losses by dry deposition was about 69% of the total compared 0.3% for acid rain neutralization, which was less than the natural carbonate dissolution losses of 0.8%. For the bronze, the mean Cu2+ losses were 70.6% by SO42- dry deposition and 23% by NO3- dry deposition compared to 6.4% by acid rain neutralization. Thus for both cases the wet

Low-fluorine Stockwork Molybdenite Deposits

Science.gov (United States)

Ludington, Steve; Hammarstrom, Jane; Piatak, Nadine M.

2009-01-01

Low-fluorine stockwork molybdenite deposits are closely related to porphyry copper deposits, being similar in their tectonic setting (continental volcanic arc) and the petrology (calc-alkaline) of associated igneous rock types. They are mainly restricted to the Cordillera of western Canada and the northwest United States, and their distribution elsewhere in the world may be limited. The deposits consist of stockwork bodies of molybdenite-bearing quartz veinlets that are present in and around the upper parts of intermediate to felsic intrusions. The deposits are relatively low grade (0.05 to 0.2 percent Mo), but relatively large, commonly >50 million tons. The source plutons for these deposits range from granodiorite to granite in composition; the deposits primarily form in continental margin subduction-related magmatic arcs, often concurrent with formation of nearby porphyry copper deposits. Oxidation of pyrite in unmined deposits or in tailings and waste rock during weathering can lead to development of acid-rock drainage and limonite-rich gossans. Waters associated with low-fluorine stockwork molybdenite deposits tend to be nearly neutral in pH; variable in concentrations of molybdenum (10,000 ug/L); below regulatory guidelines for copper, iron, lead, zinc, and mercury; and locally may exceed guidelines for arsenic, cadmium, and selenium.

Fat, oil and grease deposits in sewers: characterisation of deposits and formation mechanisms.

Science.gov (United States)

Williams, J B; Clarkson, C; Mant, C; Drinkwater, A; May, E

2012-12-01

Fat, oil and grease deposits (FOG) in sewers are a major problem and can cause sewer overflows, resulting in environmental damage and health risks. Often simplistically portrayed as cooling of fats, recent research has suggested that saponification may be involved in FOG formation. However there are still questions about the mechanisms effecting transformations in sewers and the role and source of metal cations involved in saponification. This study characterises FOG deposits from pumping stations, sewers and sewage works from different water hardness zones across the UK. The sites all had previous problems with FOG and most catchments contained catering and food preparation establishments. The FOG deposits were highly variable with moisture content ranging from 15 to 95% and oil content from 0 to 548 mg/g. Generally the pumping stations had lower moisture content and higher fat content, followed by the sewers then the sewage works. The water in contact with the FOG had high levels of oil (mean of about 800 mg/L) and this may indicate poor kitchen FOG management practices. FOG fatty acid profiles showed a transformation from unsaturated to saturated forms compared to typical cooking oils. This seems to relate to ageing in the sewer network or the mechanism of formation, as samples from pumping stations had higher proportions of C18:1 compared to C16. This may be due to microbial transformations by bacteria such as Clostridium sp. in a similar process to adipocere formation. There was an association between water hardness and increased Ca levels in FOG along with harder deposits and higher melting points. A link between FOG properties and water hardness has not been previously reported for field samples. This may also be due to microbial processes, such as biocalcification. By developing the understanding of these mechanisms it may be possible to more effectively control FOG deposits, especially when combined with promotion of behavioural change. Copyright © 2012

Sortilin Fragments Deposit at Senile Plaques in Human Cerebrum

Directory of Open Access Journals (Sweden)

Xia Hu

2017-06-01

Full Text Available Genetic variations in the vacuolar protein sorting 10 protein (Vps10p family have been linked to Alzheimer’s disease (AD. Here we demonstrate deposition of fragments from the Vps10p member sortilin at senile plaques (SPs in aged and AD human cerebrum. Sortilin changes were characterized in postmortem brains with antibodies against the extracellular and intracellular C-terminal domains. The two antibodies exhibited identical labeling in normal human cerebrum, occurring in the somata and dendrites of cortical and hippocampal neurons. The C-terminal antibody also marked extracellular lesions in some aged and all AD cases, appearing as isolated fibrils, mini-plaques, dense-packing or circular mature-looking plaques. Sortilin and β-amyloid (Aβ deposition were correlated overtly in a region/lamina- and case-dependent manner as analyzed in the temporal lobe structures, with co-localized immunofluorescence seen at individual SPs. However, sortilin deposition rarely occurred around the pia, at vascular wall or in areas with typical diffuse Aβ deposition, with the labeling not enhanced by section pretreatment with heating or formic acid. Levels of a major sortilin fragment ~15 kDa, predicted to derive from the C-terminal region, were dramatically elevated in AD relative to control cortical lysates. Thus, sortilin fragments are a prominent constituent of the extracellularly deposited protein products at SPs in human cerebrum.

Deposition of acidifying compounds

International Nuclear Information System (INIS)

Fowler, D.; Cape, J.N.; Sutton, M.A.; Mourne, R.; Hargreaves, K.J.; Duyzer, J.H.; Gallagher, M.W.

1992-01-01

Inputs of acidifying compounds to terrestrial ecosystems include deposition of the gases NO 2 , NO, HNO 2 , HNO 3 , NH 3 and SO 2 and the ions NO 3- , NH 4+ , SO 4 2- and H + in precipitation, cloud droplets and particles. Recent research has identified particular ecosystems and regions in which terrestrial effects are closely linked with specific deposition processes. This review paper identifies areas in which important developments have occurred during the last five years and attempts to show which aspects of the subject are most important for policy makers. Amongst the conclusions drawn, the authors advise that current uncertainties in estimates of S and N inputs by dry deposition should be incorporated in critical load calculations, and that, in regions dominated by wet deposition, spatial resolution of total inputs should be improved to match the current scales of information on landscape sensitivity to acidic inputs. 44 refs., 9 figs

Usnic acid controls the acidity tolerance of lichens

International Nuclear Information System (INIS)

Hauck, Markus; Juergens, Sascha-Rene

2008-01-01

The hypotheses were tested that, firstly, lichens producing the dibenzofuran usnic acid colonize substrates characterized by specific pH ranges, secondly, this preferred pH is in a range where soluble usnic acid and its corresponding anion occur in similar concentrations, and thirdly, usnic acid makes lichens vulnerable to acidity. Lichens with usnic acid prefer an ambient pH range between 3.5 and 5.5 with an optimum between 4.0 and 4.5. This optimum is close to the pK a1 value of usnic acid of 4.4. Below this optimum pH, dissolved SO 2 reduces the chlorophyll fluorescence yield more in lichens with than without their natural content of usnic acid. This suggests that usnic acid influences the acidity tolerance of lichens. The putative mechanism of the limited acidity tolerance of usnic acid-containing lichens is the acidification of the cytosol by molecules of protonated usnic acid shuttling protons through the plasma membrane at an apoplastic pH a1 . - Combined field and experimental data suggest that usnic acid makes lichens sensitive to acidity at pH <3.5

Acid Deposition Maps in Spain; Mapas de Deposito Acido en Espana

Energy Technology Data Exchange (ETDEWEB)

Artinano, B; Cabal, H; Garcia, C

1998-07-01

Animal and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To do this, updated databases with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5x5 Km{sup 2} grid which allow to assess the methodology used in Europe to obtain the maps of excedances over the critical loads of pollutants. (Author) 32 refs.

Acid Deposition Maps in Spain; Mapas de Deposito Acido en Espana

Energy Technology Data Exchange (ETDEWEB)

Artinano, B.; Cabal, H.; Garcia, C. [CIEMAT. Madrid (Spain)

1998-12-31

Annual and monthly deposition velocity and total sulfur deposition maps have been performed for the peninsular Spain for 1992 by using the inferential method. To de this, updated database with high space and time resolution, for land uses (CORINE) and meteorological information from analysis modelling for the same year, have been utilized. The final result are deposition maps in a 5 x 5 km``2 grid which allow to assess the methodology used in Europe to obtain the maps of excedance over the critical loads of pollutants. (Author) 32 refs.

Modelling regional response of lakewater chemistry to changes in acidic deposition: the MAGIC model applied to lake surveys in southernmost Norway 1974-1986-1995

Directory of Open Access Journals (Sweden)

B. J. Cosby

1998-01-01

Full Text Available Two methods for modelling regional responses of lake water quality to changes in acidic deposition in southernmost Norway were examined. Both methods are based upon the MAGIC model but differ in mode of regional application; one uses site-specific while the other uses Monte-Carlo methods for model calibration. The simulations of regional responses from both methods were compared with observed responses based on data from three lake surveys in southernmost Norway conducted in 1974, 1986 and 1995. The regional responses of the two modelling approaches were quite similar and agreed well with the observed regional distributions of lakewater chemistry variables. From 1974 to 1986 the observed data indicated that despite a decline of approximately 10% in sulphate (SO4 deposition, the mean acid neutralizing capacity (ANC of lakes in southernmost Norway declined by approximately 6 μeq l-1. Both modelling approaches simulated no change or a very small decline in mean ANC for that period. From 1986 to 1995 the observed data indicated that, in response to an approximate 40% decline in SO4 deposition, the mean ANC of lakes in southernmost Norway increased by 11-16 μeq l-1. The modelling approaches simulated increases of 9-10 μeq l-1 in mean ANC for the same period. Both simulations and observations indicate that > 65% of lakes in southernmost Norway were acidic in 1974 and 1995. Both simulation methods predict that >65% of the lakes in southernmost Norway will have positive ANC values within 10 years of reductions of SO4 deposition to 20% of 1974 levels. Of the two regionalization methods the site-specific method appears preferable, because whereas the Monte-Carlo method gives results for a region as a whole, the site-specific method also reveals patterns within the region. The maintenance of a one-to-one correspondence between simulated and observed systems means that simulation results can be mapped for a geographically explicit presentation of model

Critical Factors Controlling Pd and Pt Potential in Porphyry Cu–Au Deposits: Evidence from the Balkan Peninsula

Directory of Open Access Journals (Sweden)

Demetrios G. Eliopoulos

2014-03-01

Full Text Available Porphyry Cu–Au–Pd±Pt deposits are significant Au resources, but their Pd and Pt potential is still unknown. Elevated Pd, Pt (hundreds of ppb and Au contents are associated with typical stockwork magnetite-bornite-chalcopyrite assemblages, at the central parts of certain porphyry deposits. Unexpected high grade Cu–(Pd+Pt (up to 6 ppm mineralization with high Pd/Pt ratios at the Elatsite porphyry deposit, which is found in a spatial association with the Chelopech epithermal deposit (Bulgaria and the Skouries porphyry deposit, may have formed during late stages of an evolved hydrothermal system. Estimated Pd, Pt and Au potential for porphyry deposits is consistent with literature model calculations demonstrating the capacity of aqueous vapor and brine to scavenge sufficient quantities of Pt and Pd, and could contribute to the global platinum-group element (PGE production. Critical requirements controlling potential of porphyry deposits may be from the metals contained in magma (metasomatized asthenospheric mantle wedge as indicated by significant Cr, Co, Ni and Re contents. The Cr content may be an indicator for the mantle input.

Effects of acid deposition on Dutch forest ecosystems

NARCIS (Netherlands)

Vries, de W.; Leeters, E.E.J.M.; Hendriks, C.M.A.

1995-01-01

Effects of elevated sulphur and nitrogen deposition on the solution chemistry of Dutch forest soils are mainly manifested by increased aluminium concentrations, associated with increased concentrations of sulphate and nitrate. Critical aluminium/base cation ratios are often exceeded below 20 cm soil

Modelling impacts of temperature, and acidifying and eutrophying deposition on DOC trends

Science.gov (United States)

Sawicka, Kasia; Rowe, Ed; Evans, Chris; Monteith, Don; Vanguelova, Elena; Wade, Andrew; Clark, Joanna

2017-04-01

Surface water dissolved organic carbon (DOC) concentrations in large parts of the northern hemisphere have risen over the past three decades, raising concern about enhanced contributions of carbon to the atmosphere and seas and oceans. The effect of declining acid deposition has been identified as a key control on DOC trends in soil and surface waters, since pH and ionic strength affect sorption and desorption of DOC. However, since DOC is derived mainly from recently-fixed carbon, and organic matter decomposition rates are considered sensitive to temperature, uncertainty persists regarding the extent to the relative importance of different drivers that affect these upward trends. We ran the dynamic model MADOC (Model of Acidity and Soil Organic Carbon) for a range of UK soils (podzols, gleysols and peatland), for which the time-series were available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20 years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to elevate the DOC recovery trajectory significantly. The second most influential cause of rising DOC in the model simulations was N deposition in ecosystems that are N-limited and respond with stimulated plant growth. Although non-marine chloride deposition made some contribution to acidification and recovery, it was not amongst the main drivers of DOC change. Warming had almost no effect on modelled historic DOC trends, but may prove to be a significant driver of DOC in future via its influence

Nanotune: A Novel Approach to Control the Deposition and Fate of Particles in Porous Media

Science.gov (United States)

Sethi, R.; Bianco, C.; Tosco, T.; Tiraferri, A.; Patiño Higuita, J. E.

2017-12-01

Nanoremediation is an innovative environmental nanotechnology aimed at reclaiming contaminated aquifers. It consists in the subsurface injection of a reactive colloidal suspension for the in-situ treatment of pollutants. The greatest challenges faced by engineers to advance nanoremediation are the effective delivery and the appropriate dosing of the nanoparticles into the subsoil. These are necessary for the correct emplacement of the in situ reactive zone and to minimize the overall cost of the reclamation and the potential secondary risks associated to the uncontrolled migration of the injected particles. In this study, a model assisted strategy, NanoTune, is developed to control the distribution of colloids in porous media. The proposed approach consists in the sequential injection of a stable suspension of reactive nanoparticles and of a destabilizing agent with the aim of creating a reactive zone within a targeted portion of the contaminated aquifer. The controlled and irreversible deposition of the particles is achieved by inducing the mixing of the two fluids in the desired portion of the aquifer. This approach is here exemplified by the delivery of humic acid-stabilized iron oxide nanoparticles (FeOx), a typical reagent for in situ immobilization of heavy metals. Divalent cations, which are known to cause rapid aggregation of the suspension because of their strong interaction with the humic acid coating, are used as destabilizing agents. The injection strategy is here applied in 1D columns to create a reactive zone for heavy metal removal in the central region of the sandy bed. The software MNMs was used to assess the correct sequence and duration of the injection of the different solutions in the 1D medium. Moreover, the numerical code MNM3D (MNM3D - Micro and Nanoparticle transport Model in 3D geometries) was developed by the authors of this work to support the case-specific design of the injection strategy during field scale applications. The Nano

High variability of the heterogeneous ice nucleation potential of oxalic acid dihydrate and sodium oxalate

OpenAIRE

R. Wagner; O. Möhler; H. Saathoff; M. Schnaiter; T. Leisner

2010-01-01

The heterogeneous ice nucleation potential of airborne oxalic acid dihydrate and sodium oxalate particles in the deposition and condensation mode has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 244 and 228 K. Previous laboratory studies have highlighted the particular role of oxalic acid dihydrate as the only species amongst a variety of other investigated dicarboxylic acids to ...

Phase-controlled preparation of TiO{sub 2} films and micro(nano)spheres by low-temperature chemical bath deposition

Energy Technology Data Exchange (ETDEWEB)

Wang, Mingsong, E-mail: wangms@mail.ujs.edu.cn [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Li, Qihui; Yu, Haiyan [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Hur, Seung Hyun [Department of Chemical Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Kim, Eui Jung, E-mail: ejkim@ulsan.ac.kr [Department of Chemical Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of)

2013-11-25

Highlights: •Simultaneously preparation of TiO{sub 2} films and sphere-like precipitates by low-temperature chemical bath deposition. •The same building blocks observed in the films and precipitates. •Cluster-by-cluster attachment is succeeded by the ion-by-ion growth. •Phase-controlled growth of TiO{sub 2} by the effects of solvent or fluorine ion. -- Abstract: TiO{sub 2} films and micro(nano)spheres have been simultaneously prepared by means of low-temperature chemical bath deposition (CBD). The films and precipitates are found to be constructed of the same building blocks regardless of the bath conditions. Thin nanosheets of ca. 20 nm in thickness serve as the building blocks of rutile TiO{sub 2} grown in an acidic bath. They aggregate to form spheres to reduce the surface energy of the precipitates, while in the films they grow into discrete crystallites on the seeded substrate. Fine control over the crystalline phase of TiO{sub 2} is achieved by replacing some water with ethanol or the addition of NH{sub 4}F. A gradual transition from rutile to anatase is observed as the ethanol and NH{sub 4}F contents are increased. Moreover, the crystallite size of TiO{sub 2} is significantly reduced and there exists monodisperse nanoparticles and aggregate microspheres in the products modified with ethanol and NH{sub 4}F, respectively. This size-dependent phase transition is consistent with previous theoretical and thermodynamic studies. The facile tune of the TiO{sub 2} phase by low-temperature CBD method may be useful to improve the performance of TiO{sub 2} for its various applications.

Leaf area and foliar biomass relationships in northern hardwood forests located along an 800 km acid deposition gradient

International Nuclear Information System (INIS)

Burton, A.J.; Pregitzer, K.S.; Reed, D.D.

1991-01-01

The canopies of northern hardwood forests dominated by sugar maple (Acer saccharum Marsh.) were examined at five locations spanning 800 km along an acid deposition and climatic gradient in the Great Lakes region. Leaf area index (LAI) calculated from litterfall ranged from 6.0 to 8.0 in 1988, from 4.9 to 7.9 in 1989, and from 5.3 to 7.8 in 1990. The data suggest that maximum LAI for the sites is between 7 and 8. Insect defoliation and the allocation of assimilates to reproductive parts in large seed years reduced LAI by up to 34%. Allometric equations for leaf area and foliar biomass were not significantly different among sites. They predicted higher LAI values than were estimated from litterfall and could not account for the influences of defoliation and seed production. Canopy transmittance was a viable alternative for estimating LAI. Extinction coefficients (K) of 0.49 to 0.65 were appropriate for solar elevations of 63 degree to 41 degree. Patterns of specific leaf area (SLA) were similar for the sites. Average sugar maple SLA increased from 147 cm 2 g -1 in the upper 5 m of the canopy to 389 cm 2 g -1 in the seeding layer. Litterfall SLA averaged 196 cm 2 g -1 for all species and 192 cm 2 g -1 for sugar maple. Similarity among the sites in allometric relationships, maximum LAI, canopy transmittance, and patterns of SLA suggests these characteristics were controlled primarily by the similar nutrient and moisture availability at the sites. A general increasing trend in litter production along the gradient could not be attributed to N deposition or length of growing season due to year to year variability resulting from insect defoliation and seed production

Solid oxide fuel cell electrolytes produced via very low pressure suspension plasma spray and electrophoretic deposition

Science.gov (United States)

Fleetwood, James D.

Solid oxide fuel cells (SOFCs) are a promising element of comprehensive energy policies due to their direct mechanism for converting the oxidization of fuel, such as hydrogen, into electrical energy. Both very low pressure plasma spray and electrophoretic deposition allow working with high melting temperature SOFC suspension based feedstock on complex surfaces, such as in non-planar SOFC designs. Dense, thin electrolytes of ideal composition for SOFCs can be fabricated with each of these processes, while compositional control is achieved with dissolved dopant compounds that are incorporated into the coating during deposition. In the work reported, sub-micron 8 mole % Y2O3-ZrO2 (YSZ) and gadolinia-doped ceria (GDC), powders, including those in suspension with scandium-nitrate dopants, were deposited on NiO-YSZ anodes, via very low pressure suspension plasma spray (VLPSPS) at Sandia National Laboratories' Thermal Spray Research Laboratory and electrophoretic deposition (EPD) at Purdue University. Plasma spray was carried out in a chamber held at 320 - 1300 Pa, with the plasma composed of argon, hydrogen, and helium. EPD was characterized utilizing constant current deposition at 10 mm electrode separation, with deposits sintered from 1300 -- 1500 °C for 2 hours. The role of suspension constituents in EPD was analyzed based on a parametric study of powder loading, powder specific surface area, polyvinyl butyral (PVB) content, polyethyleneimine (PEI) content, and acetic acid content. Increasing PVB content and reduction of particle specific surface area were found to eliminate the formation of cracks when drying. PEI and acetic acid content were used to control suspension stability and the adhesion of deposits. Additionally, EPD was used to fabricate YSZ/GDC bilayer electrolyte systems. The resultant YSZ electrolytes were 2-27 microns thick and up to 97% dense. Electrolyte performance as part of a SOFC system with screen printed LSCF cathodes was evaluated with peak

Controllable chemical vapor deposition of large area uniform nanocrystalline graphene directly on silicon dioxide

DEFF Research Database (Denmark)

Sun, Jie; Lindvall, Niclas; Cole, Matthew T.

2012-01-01

Metal-catalyst-free chemical vapor deposition (CVD) of large area uniform nanocrystalline graphene on oxidized silicon substrates is demonstrated. The material grows slowly, allowing for thickness control down to monolayer graphene. The as-grown thin films are continuous with no observable pinholes...

Ecological ranges for the pH and NO3 of syntaxa: a new basis for the estimation of critical loads for acid and nitrogen deposition

NARCIS (Netherlands)

Wamelink, G.W.W.; Goedhart, P.W.; Malinowska, A.H.; Frissel, J.Y.; Wegman, R.M.A.; Slim, P.A.; Dobben, van H.F.

2011-01-01

Question: Can the abiotic ranges of syntaxonomic units (associations) in terms of pH and nitrate concentration be estimated and then in principle be used to estimate critical loads for acid and nitrogen deposition? Location: Europe. Methods: Using splines, abiotic ranges of syntaxonomic units were

A case study of the relative effects of power plant nitrogen oxides and sulfur dioxide emission reductions on atmospheric nitrogen deposition.

Science.gov (United States)

Vijayaraghavan, Krish; Seigneur, Christian; Bronson, Rochelle; Chen, Shu-Yun; Karamchandani, Prakash; Walters, Justin T; Jansen, John J; Brandmeyer, Jo Ellen; Knipping, Eladio M

2010-03-01

The contrasting effects of point source nitrogen oxides (NOx) and sulfur dioxide (SO2) air emission reductions on regional atmospheric nitrogen deposition are analyzed for the case study of a coal-fired power plant in the southeastern United States. The effect of potential emission reductions at the plant on nitrogen deposition to Escambia Bay and its watershed on the Florida-Alabama border is simulated using the three-dimensional Eulerian Community Multiscale Air Quality (CMAQ) model. A method to quantify the relative and individual effects of NOx versus SO2 controls on nitrogen deposition using air quality modeling results obtained from the simultaneous application of NOx and SO2 emission controls is presented and discussed using the results from CMAQ simulations conducted with NOx-only and SO2-only emission reductions; the method applies only to cases in which ambient inorganic nitrate is present mostly in the gas phase; that is, in the form of gaseous nitric acid (HNO3). In such instances, the individual effects of NOx and SO2 controls on nitrogen deposition can be approximated by the effects of combined NOx + SO2 controls on the deposition of NOy, (the sum of oxidized nitrogen species) and reduced nitrogen species (NHx), respectively. The benefit of controls at the plant in terms of the decrease in nitrogen deposition to Escambia Bay and watershed is less than 6% of the overall benefit due to regional Clean Air Interstate Rule (CAIR) controls.

Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition

International Nuclear Information System (INIS)

Podestà, Alessandro; Borghi, Francesca; Indrieri, Marco; Bovio, Simone; Piazzoni, Claudio; Milani, Paolo

2015-01-01

Great emphasis is placed on the development of integrated approaches for the synthesis and the characterization of ad hoc nanostructured platforms, to be used as templates with controlled morphology and chemical properties for the investigation of specific phenomena of great relevance in interdisciplinary fields such as biotechnology, medicine, and advanced materials. Here, we discuss the crucial role and the advantages of thin film deposition strategies based on cluster-assembling from supersonic cluster beams. We select cluster-assembled nanostructured titania (ns-TiO 2 ) as a case study to demonstrate that accurate control over morphological parameters can be routinely achieved, and consequently, over several relevant interfacial properties and phenomena, like surface charging in a liquid electrolyte, and proteins and nanoparticles adsorption. In particular, we show that the very good control of nanoscale morphology is obtained by taking advantage of simple scaling laws governing the ballistic deposition regime of low-energy, mass-dispersed clusters with reduced surface mobility

Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition

Energy Technology Data Exchange (ETDEWEB)

Podestà, Alessandro, E-mail: alessandro.podesta@mi.infn.it, E-mail: pmilani@mi.infn.it; Borghi, Francesca; Indrieri, Marco; Bovio, Simone; Piazzoni, Claudio; Milani, Paolo, E-mail: alessandro.podesta@mi.infn.it, E-mail: pmilani@mi.infn.it [Centro Interdisciplinare Materiali e Interfacce Nanostrutturati (C.I.Ma.I.Na.), Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy)

2015-12-21

Great emphasis is placed on the development of integrated approaches for the synthesis and the characterization of ad hoc nanostructured platforms, to be used as templates with controlled morphology and chemical properties for the investigation of specific phenomena of great relevance in interdisciplinary fields such as biotechnology, medicine, and advanced materials. Here, we discuss the crucial role and the advantages of thin film deposition strategies based on cluster-assembling from supersonic cluster beams. We select cluster-assembled nanostructured titania (ns-TiO{sub 2}) as a case study to demonstrate that accurate control over morphological parameters can be routinely achieved, and consequently, over several relevant interfacial properties and phenomena, like surface charging in a liquid electrolyte, and proteins and nanoparticles adsorption. In particular, we show that the very good control of nanoscale morphology is obtained by taking advantage of simple scaling laws governing the ballistic deposition regime of low-energy, mass-dispersed clusters with reduced surface mobility.

Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition

Science.gov (United States)

Podestà, Alessandro; Borghi, Francesca; Indrieri, Marco; Bovio, Simone; Piazzoni, Claudio; Milani, Paolo

2015-12-01

Great emphasis is placed on the development of integrated approaches for the synthesis and the characterization of ad hoc nanostructured platforms, to be used as templates with controlled morphology and chemical properties for the investigation of specific phenomena of great relevance in interdisciplinary fields such as biotechnology, medicine, and advanced materials. Here, we discuss the crucial role and the advantages of thin film deposition strategies based on cluster-assembling from supersonic cluster beams. We select cluster-assembled nanostructured titania (ns-TiO2) as a case study to demonstrate that accurate control over morphological parameters can be routinely achieved, and consequently, over several relevant interfacial properties and phenomena, like surface charging in a liquid electrolyte, and proteins and nanoparticles adsorption. In particular, we show that the very good control of nanoscale morphology is obtained by taking advantage of simple scaling laws governing the ballistic deposition regime of low-energy, mass-dispersed clusters with reduced surface mobility.

Use of soil-streamwater relationships to assess regional patterns of acidic deposition effects in the northeastern USA

Science.gov (United States)

Siemion, Jason; Lawrence, Gregory B.; Murdoch, Peter S.

2013-01-01

Declines of acidic deposition levels by as much as 50% since 1990 have led to partial recovery of surface waters in the northeastern USA but continued depletion of soil calcium through this same period suggests a disconnection between soil and surface water chemistry. To investigate the role of soil-surface water interactions in recovery from acidification, the first regional survey to directly relate soil chemistry to stream chemistry during high flow was implemented in a 4144-km2 area of the Catskill region of New York, where acidic deposition levels are among the highest in the East.More than 40% of 95 streams sampled in the southern Catskill Mountains were determined to be acidified and had inorganic monomeric aluminum concentrations that exceeded a threshold that is toxic to aquatic biota. More than 80% likely exceeded this threshold during the highest flows, but less than 10% of more than 100 streams sampled were acidified in the northwestern portion of the region. Median Oa horizon soil base saturation ranged from 50% to 80% at 200 sites across the region, but median base saturation in the upper 10 cm of the B horizon was less than 20% across the region and was only 2% in the southern area. Aluminum is likely to be interfering with root uptake of calcium in the mineral horizon in approximately half the sampled watersheds. Stream chemistry was highly variable over the Catskill region and, therefore, did not always reflect the calcium depletion of the B horizon that our sampling suggested was nearly ubiquitous throughout the region. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

USGS Tracks Acid Rain

Science.gov (United States)

Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

1995-01-01

The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

Fuzzy Control of a Lead Acid Battery Charger

Directory of Open Access Journals (Sweden)

A. DAOUD

2005-03-01

Full Text Available In this paper, an alternative battery charging control technique based on fuzzy logic for photovoltaic (PV applications is presented. A PV module is connected to a buck type DC/DC power converter and a microcontroller based unit is used to control the lead acid battery charging voltage. The fuzzy control is used due to the simplicity of implementation, robustness and independence from the complex mathematical representation of the battery. The usefulness of this control method is confirmed by experiments.

Vacuum thermal evaporation of polyaniline doped with camphor sulfonic acid

Energy Technology Data Exchange (ETDEWEB)

Boyne, Devon; Menegazzo, Nicola; Pupillo, Rachel C.; Rosenthal, Joel; Booksh, Karl S., E-mail: kbooksh@udel.edu [Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716 (United States)

2015-05-15

Intrinsically conducting polymers belong to a class of organic polymers with intriguing electronic and physical properties specifically for electro-optical applications. Significant interest into doped polyaniline (PAni) can be attributed to its high conductivity and environmental stability. Poor dissolution in most solvents has thus far hindered the successful integration of PAni into commercial applications, which in turn, has led to the investigations of various deposition and acidic doping methods. Physical vapor deposition methods, including D.C. magnetron sputtering and vacuum thermal evaporation, have shown exceptional control over physical film properties (thickness and morphology). However, resulting films are less conductive than films deposited by conventional methods (i.e., spin and drop casting) due to interruption of the hyperconjugation of polymer chains. Specifically, vacuum thermal evaporation requires a postdoping process, which results in incorporation of impurities and oxidation of surface moieties. In this contribution, thermally evaporated films, sequentially doped by vacuum evaporation of an organic acid (camphorsulfonic acid, CSA) is explored. Spectroscopic evidence confirms the successful doping of PAni with CSA while physical characterization (atomic force microscopy) suggests films retain good morphology and are not damaged by the doping process. The procedure presented herein also combines other postpreparation methods in an attempt to improve conductivity and/or substrate adhesion.

Quantification of controls on regional rockfall activity and talus deposition, Kananaskis, Canadian Rockies

Science.gov (United States)

Thapa, Prasamsa; Martin, Yvonne E.; Johnson, E. A.

2017-12-01

Rockfall is a significant geomorphic process in many mountainous regions that also poses a notable natural hazard risk. Most previous studies of rockfall erosion have investigated the mechanics and rates of local rockwall retreat and talus deposition, with only a few investigations of rockfall and/or associated talus considering larger spatial scales (i.e., drainage basin, mountain range). The purpose of the current research is to investigate the areal extent of rockfall-talus and controlling factors of its distribution over regional spatial scales (of order 102 km2) in Kananaskis, Canadian Rockies to inform our understanding of its significance in mountain development. To achieve this goal, a large talus inventory is collected and analyzed for 11 steep tributaries of the Kananaskis River, Canadian Rockies. Talus accumulations associated with rockfall provide evidence about the nature and rates of rockfall activity that supplies sediment to these deposits and are the focus of the present study. To quantify the controls of rockfall-talus activity in this region, we analyze the association of talus deposits with structural geology, glacial topography, and temperature-related weathering (i.e., frost cracking). A total of 324 talus polygons covering a surface area of 28.51 km2 are delineated within the 11 study basins, with the number of talus polygons in each study basin ranging from 1 to 73. Analysis of the talus inventory shows that cirques and glacially sculpted valleys are locations of notable talus accumulation in Kananaskis, with other locations of significant talus deposition being associated with thrust faults. We also found that the upper elevations at which talus deposits are typically found are the general range of elevations experiencing a notable number of days in the frost cracking window when this window is defined as - 3 to - 15 °C; no such association is found for the frost cracking window of - 3 to - 8 °C. Estimates of average erosion rates for all

Mechanism research on coupling effect between dew point corrosion and ash deposition

International Nuclear Information System (INIS)

Wang, Yun-Gang; Zhao, Qin-Xin; Zhang, Zhi-Xiang; Zhang, Zhi-Chao; Tao, Wen-Quan

2013-01-01

In order to study the coupling mechanism between ash deposition and dew point corrosion, five kinds of tube materials frequently used as anti-dew point corrosion materials were selected as research objects. Dew point corrosion and ash deposition experiments were performed with a new type experimental device in a Chinese thermal power plant. The microstructures of the materials and the composition of ash deposition were analyzed by X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS). The results showed that the ash deposition layer could be divided into non-condensation zone, the main condensation zone and the secondary condensation zone. The acid vapor condensed in the main condensation zone rather than directly on the tube wall surface. The dew point corrosion mainly is oxygen corrosion under the condition of the viscosity ash deposition, and the corrosion products are composed of the ash and acid reaction products in the outer layer, iron sulfate in the middle layer, and iron oxide in the inner layer. The innermost layer is the main corrosion layer. With the increase of the tube wall temperature, the ash deposition changes from the viscosity ash deposition to the dry loose ash deposition, the ash deposition rate decreases dramatically and dew point corrosion is alleviated efficiently. The sulfuric dew point corrosion resistance of the five test materials is as follows: 316L > ND > Corten>20G > 20 steel. -- Highlights: ► Dew point corrosion and ash deposition tests of five materials were performed. ► Acid vapor condensed in the ash deposit rather than directly on the tube surface. ► Dew point corrosion resistance is as follow: 316L > ND > Corten>20G > 20 steel. ► Dew point corrosion mainly is oxygen corrosion under viscosity ash deposition

Acid rain science and politics in Japan: a history of knowledge and action toward sustainability

Energy Technology Data Exchange (ETDEWEB)

Ken Wilkening

2004-07-01

This is a pioneering work in environmental and Asian history as well as an in-depth analysis of the influence of science on domestic and international environmental politics. The book is composed of the following chapters. Chapter 2 introduces the general set of concepts used to analyze the science-politics nexus. These concepts are employed in the remainder of the book to track and explain the relationship between science and policy related to the acid deposition problem in Japan. Chapter 3 discusses nature, culture, and the acid deposition problem in Japan. It begins with a brief introduction to the acid deposition problem in general. It continues with an overview of elements of Japan's natural environment and culture that are relevant to its acid deposition problems. This is followed by a quick sketch of the history of science in Japan, which in turn serves as a preamble for describing in the final section the environmental and acid deposition chronologies used to organize analysis of Japan's acid deposition history. The swath of history between 1868 and the present (circa 2000) is divided into five environmental eras and six acid deposition periods. Chapters 4-9 discuss in detail each of the six acid deposition periods. Chapter 10 synthesizes and summarizes what was learned in the process of analyzing Japan's acid deposition history, and draws lessons that might be applied to the challenge of creating sustainable societies in Japan, Asia, and the rest of the world. An appendix describes the present state of acid deposition science in Japan.

Control of instability in nitric acid evaporators for plutonium processing

International Nuclear Information System (INIS)

1998-03-01

Improved control of the nitric acid process evaporators requires the detection of spontaneously unstable operating conditions. This process reduces the volume of contaminated liquid by evaporating nitric acid and concentrating salt residues. If a instability is identified quickly, prompt response can avert distillate contamination. An algorithm applied to the runtime data was evaluated to detect this situation. A snapshot of data from a histogram in the old process control software was captured during the unstable conditions and modeled

Water availability drives gas exchange and growth of trees in northeastern US, not elevated CO2 and reduced acid deposition.

Science.gov (United States)

Levesque, Mathieu; Andreu-Hayles, Laia; Pederson, Neil

2017-04-10

Dynamic global vegetation models (DGVM) exhibit high uncertainty about how climate change, elevated atmospheric CO 2 (atm. CO 2 ) concentration, and atmospheric pollutants will impact carbon sequestration in forested ecosystems. Although the individual roles of these environmental factors on tree growth are understood, analyses examining their simultaneous effects are lacking. We used tree-ring isotopic data and structural equation modeling to examine the concurrent and interacting effects of water availability, atm. CO 2 concentration, and SO 4 and nitrogen deposition on two broadleaf tree species in a temperate mesic forest in the northeastern US. Water availability was the strongest driver of gas exchange and tree growth. Wetter conditions since the 1980s have enhanced stomatal conductance, photosynthetic assimilation rates and, to a lesser extent, tree radial growth. Increased water availability seemingly overrides responses to reduced acid deposition, CO 2 fertilization, and nitrogen deposition. Our results indicate that water availability as a driver of ecosystem productivity in mesic temperate forests is not adequately represented in DGVMs, while CO 2 fertilization is likely overrepresented. This study emphasizes the importance to simultaneously consider interacting climatic and biogeochemical drivers when assessing forest responses to global environmental changes.

Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime Using Controlled Calorimetry

International Nuclear Information System (INIS)

Don W. Miller; Andrew Kauffmann; Eric Kreidler; Dongxu Li; Hanying Liu; Daniel Mills; Thomas D. Radcliff; Joseph Talnagi

2001-01-01

A comprehensive description of the accomplishments of the DOE grant titled, ''Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime using Controlled Calorimetry''

Size- and density-controlled deposition of Ag nanoparticle films by a novel low-temperature spray chemical vapour deposition method—research into mechanism, particle growth and optical simulation

Energy Technology Data Exchange (ETDEWEB)

Liu, Yang, E-mail: yang.liu@helmholtz-berlin.de; Plate, Paul, E-mail: paul.plate@helmholtz-berlin.de; Hinrichs, Volker; Köhler, Tristan; Song, Min; Manley, Phillip; Schmid, Martina [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (Germany); Bartsch, Peter [Beuth Hochschule für Technik Berlin, Fachbereich VIII Maschinenbau, Veranstaltungstechnik, Verfahrenstechnik (Germany); Fiechter, Sebastian; Lux-Steiner, Martha Ch. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (Germany); Fischer, Christian-Herbert [Freie Universität Berlin, Institute of Chemistry and Biochemistry (Germany)

2017-04-15

Ag nanoparticles have attracted interest for plasmonic absorption enhancement of solar cells. For this purpose, well-defined particle sizes and densities as well as very low deposition temperatures are required. Thus, we report here a new spray chemical vapour deposition method for producing Ag NP films with independent size and density control at substrate temperatures even below 100 °C, which is much lower than for many other techniques. This method can be used on different substrates to deposit Ag NP films. It is a reproducible, low-cost process which uses trimethylphosphine (hexafluoroacetylacetonato) silver as a precursor in alcoholic solution. By systematic variation of deposition parameters and classic experiments, mechanisms of particle growth and of deposition processes as well as the low decomposition temperature of the precursor could be explained. Using the 3D finite element method, absorption spectra of selected samples were simulated, which fitted well with the measured results. Hence, further applications of such Ag NP films for generating plasmonic near field can be predicted by the simulation.

Size- and density-controlled deposition of Ag nanoparticle films by a novel low-temperature spray chemical vapour deposition method—research into mechanism, particle growth and optical simulation

International Nuclear Information System (INIS)

Liu, Yang; Plate, Paul; Hinrichs, Volker; Köhler, Tristan; Song, Min; Manley, Phillip; Schmid, Martina; Bartsch, Peter; Fiechter, Sebastian; Lux-Steiner, Martha Ch.; Fischer, Christian-Herbert

2017-01-01

Ag nanoparticles have attracted interest for plasmonic absorption enhancement of solar cells. For this purpose, well-defined particle sizes and densities as well as very low deposition temperatures are required. Thus, we report here a new spray chemical vapour deposition method for producing Ag NP films with independent size and density control at substrate temperatures even below 100 °C, which is much lower than for many other techniques. This method can be used on different substrates to deposit Ag NP films. It is a reproducible, low-cost process which uses trimethylphosphine (hexafluoroacetylacetonato) silver as a precursor in alcoholic solution. By systematic variation of deposition parameters and classic experiments, mechanisms of particle growth and of deposition processes as well as the low decomposition temperature of the precursor could be explained. Using the 3D finite element method, absorption spectra of selected samples were simulated, which fitted well with the measured results. Hence, further applications of such Ag NP films for generating plasmonic near field can be predicted by the simulation.

Zinc-Nickel Codeposition in Sulfate Solution Combined Effect of Cadmium and Boric Acid

Directory of Open Access Journals (Sweden)

Y. Addi

2011-01-01

Full Text Available The combined effect of cadmium and boric acid on the electrodeposition of zinc-nickel from a sulfate has been investigated. The presence of cadmium ion decreases zinc in the deposit. In solution, cadmium inhibits the zinc ion deposition and suppresses it when deposition potential value is more negative than −1.2 V. Low concentration of CdSO4 reduces the anomalous nature of Zn-Ni deposit. Boric acid decreases current density and shifts potential discharge of nickel and hydrogen to more negative potential. The combination of boric acid and cadmium increases the percentage of nickel in the deposit. Boric acid and cadmium.

Facies-controlled reservoir properties in ramp-fan and slope-apron deposits, Miocene Puente Formation, Los Angeles basin

Energy Technology Data Exchange (ETDEWEB)

Lyons, K.T.; Geving, R.L.; Suchecki, R.K.

1989-03-01

The Miocene Puente Formation in outcrops of the eastern Los Angeles basin is interpreted as a succession of slope-apron and ramp-fan deposits that accumulated in a prism-rise wedge. The principal depositional components of this dominantly base-of-slope and ramp system are ramp-fan channels and lobes, and slope-channel and slope-apron channel/interchannel deposits. Facies-specific textural, compositional, and diagenetic attributes observed in thin section assist in the classification of depositional facies. Specifically, occurrence of carbonate cement, clay mineralogy, and abundance of organic material vary as a function of component facies architecture of the depositional system. Slope and ramp-fan channel-fill sandstones are characterized by pervasive carbonate cements, including poikilotopic and fine-grained calcite, fine-grained and baroque dolomite, and minor siderite. Diagenetic clays predate carbonate cements, and dolomite predates coarser, void-filling calcite. Ramp-fan lobe and interchannel deposits are carbonate free but are rich in detrital clay and organic matter. Diagenetic clays include mixed-layer illite/smectite and kaolinite. Sediments deposited in slope-apron channel fill are virtually cement free except for small amounts of authigenic illite/smectite. Slope-apron interchannel deposits are characterized by high content of organic matter and clay-rich matrix. Potential reservoir characteristics, such as grain size, sorting, and abundance of depositional clay matrix, are related to the primary sedimentary properties of depositional architectural components in the ramp-fan and slope-apron system. Additional diagenetic modifications, without consideration of compaction, were controlled by precipitation reactions associated with fluid flow along pathways related to the depositional architectural framework.

Deposition of acidifying components and base cations in Germany in the period 1987-1995

International Nuclear Information System (INIS)

Bleeker, A.; Draaijers, G.P.J; Klap, J.M.; Van Jaarsveld, J.A.

2000-01-01

The title project was carried out on behalf of and for account of the 'Umweltbundesamt' (UBA) Germany in co-operation with TNO-MEP and SC-DLO. The main products arising from this project are, for Germany, estimates of dry deposition with a high spatial resolution, which, in combination with wet deposition data, will be used for the calculation of critical load exceedances. The basic model used in this study was EDACS. This model calculates dry deposition fluxes on the basis of meteorological data and atmospheric concentrations of relevant species. As such, the project reported here further elaborates the work carried out in a previous project in 1996, with the following additions and/or improvements worked out: (a) The distribution of NH3 concentrations in Germany has now been calculated on a 5x5 km grid using the EUTREND model, while in the previous study these data were taken from the standard EMEP model; (b) Possible concepts for introducing cloud deposition into the inferential approach have been investigated, with results for a small study area in southern Germany shown; (c) Canopy exchange estimates for forest sites in Germany were related to parameters, also measured at these sites to gain better insight into the parameters controlling canopy uptake and leaching. SOx dry deposition fluxes were highest in central-east Germany, NOy fluxes in central-west Germany and NHx fluxes in north-west Germany. The highest dry deposition of potential acid (up to 15,000 eq. ha -1 y -1 in 1987) was calculated for 'Bundesland' Sachsen and the highest dry deposition load of nitrogen was calculated for Bremen (up to 2100 eq ha -1 y -1 in 1989). Dry deposition of SOx, NOy, NHx and potential acid in the 1993-1995 period decreased by 36%, 13%, 21% and 31%, respectively, compared to the 1987-1989 period The decrease in potential acid was highest in Sachsen (43%) and lowest in Baden-Wittemberg (12%). Dry deposition of non-sea salt Ca 2+ , K + , Mg 2+ and base cations decreased

Microstructure evolution in nanoporous gold thin films made from sputter-deposited precursors

International Nuclear Information System (INIS)

Gwak, Eun-Ji; Kang, Na-Ri; Baek, Un Bong; Lee, Hae Moo; Nahm, Seung Hoon; Kim, Ju-Young

2013-01-01

We fabricate almost crack-free 1.5 μm thick nanoporous gold thin films using free-corrosion dealloying and transfer processes from sputter-deposited precursors. By controlling the temperature and the concentration of the nitric acid solution during free-corrosion dealloying, we obtain ligament sizes in nanoporous gold between 22 and 155 nm. We investigate the effects of dissolution rate of Ag atoms, surface diffusivity of Au atoms and formation of Ag oxide on nanoporosity evolution

Closed-Loop Process Control for Electron Beam Freeform Fabrication and Deposition Processes

Science.gov (United States)

Taminger, Karen M. (Inventor); Hafley, Robert A. (Inventor); Martin, Richard E. (Inventor); Hofmeister, William H. (Inventor)

2013-01-01

A closed-loop control method for an electron beam freeform fabrication (EBF(sup 3)) process includes detecting a feature of interest during the process using a sensor(s), continuously evaluating the feature of interest to determine, in real time, a change occurring therein, and automatically modifying control parameters to control the EBF(sup 3) process. An apparatus provides closed-loop control method of the process, and includes an electron gun for generating an electron beam, a wire feeder for feeding a wire toward a substrate, wherein the wire is melted and progressively deposited in layers onto the substrate, a sensor(s), and a host machine. The sensor(s) measure the feature of interest during the process, and the host machine continuously evaluates the feature of interest to determine, in real time, a change occurring therein. The host machine automatically modifies control parameters to the EBF(sup 3) apparatus to control the EBF(sup 3) process in a closed-loop manner.

Laser vapor phase deposition of semiconductors

Energy Technology Data Exchange (ETDEWEB)

Karlov, N.V.; Luk' ianchuk, B.S.; Sisakian, E.V.; Shafeev, G.A.

1987-06-01

The pyrolytic effect of IR laser radiation is investigated with reference to the initiation and control of the vapor phase deposition of semiconductor films. By selecting the gas mixture composition and laser emission parameters, it is possible to control the deposition and crystal formation processes on the surface of semiconductors, with the main control action achieved due to the nonadiabatic kinetics of reactions in the gas phase and high temperatures in the laser heating zone. This control mechanism is demonstrated experimentally during the laser vapor deposition of germanium and silicon films from tetrachlorides on single-crystal Si and Ge substrates. 5 references.

Uranium deposits of Lagoa Real uranium Province, state of Bahia, Brazil

International Nuclear Information System (INIS)

Ribeiro, C.I.; Carvalho Filho, C.A. de; Hashizume, B.K.

1984-01-01

The Uranium Province of Lagoa Real is situated in the south-central part of the state of Bahia and constitutes, at the present moment, one of the most promising uranium districts of Brazil. The first anomaly was recorded in 1977 and, since then intense exploration and evaluation has been carried out in the area, resulting in the characterization of six ore deposits until now. Simultaneously, NUCLEBRAS has performed tests to establish the beneficiation characteristics of the ore, and developed preliminary mining plans. The host rock for the ore mineralization is related to sodic metasomatism and controlled by lithology and structure. The ore exhibits granoblastic texture, fine to coarse grain size, and the principal uranium minerals are uraninite, and, in minor quantities, pitchblende and uranophane. The solubility is over 90% of the U 3 O 8 contained, with an average acid consumption of 35 Kg per ton of ore treated. This paper presents a brief description of the main ore deposits and touches on their general characterisitcs. As an example, the deposit 'Jazida Cachoeira' is dealt with in greater detail, since this deposit is considered in the present context to be the most important one in the province. (Author) [pt

The Development of Reproducible and Selective Uric Acid Biosensor by Using Electrodeposited Polytyramine as Matrix Polymer

Directory of Open Access Journals (Sweden)

Manihar Situmorang

2017-11-01

Full Text Available A versatile method for the construction of reproducible and high selective uric acid biosensor is explained. Electrodeposited polytyramine is used as biosensor matrixes due to its compatibility to immobilize enzyme uric oxidase in the membrane electrode. The precise control over the charge passed during deposition of polytyramine allows concomitant control over the thickness of the deposited enzyme layers onto the surface of the electrode. The uric acid biosensor showed a sensitive response to uric acid with a linear calibration curve lies in the concentration range of 0.1–2.5 mM, slope 0.066 µA mM-1, and the limit detection was 0.01 mM uric acid (S/N = 3. The biosensor shown excellent reproducibility, the variation between response curves for uric acid lies between RSD 1% at low concentrations and up to RSD 6% at saturation concentration. Uric acid biosensor is free from normal interference. The biosensor showed good stability and to be applicable to determine uric acid in real samples. Analysis of uric acid in the reference standard serum samples by the biosensor method are all agreed with the real value from supplier. Standard samples were also analyzed independently by two methods: the present biosensor method and the standard UV-Vis spectrophotometry method, gave a correlation coefficient of 0.994. This result confirms that the biosensor method meets the rigid demands expected for uric acid in real samples.

Bayesian fuzzy logic-based estimation of electron cyclotron heating (ECH) power deposition in MHD control systems

Energy Technology Data Exchange (ETDEWEB)

Davoudi, Mehdi, E-mail: mehdi.davoudi@polimi.it [Department of Electrical and Computer Engineering, Buein Zahra Technical University, Buein Zahra, Qazvin (Iran, Islamic Republic of); Davoudi, Mohsen, E-mail: davoudi@eng.ikiu.ac.ir [Department of Electrical Engineering, Imam Khomeini International University, Qazvin, 34148-96818 (Iran, Islamic Republic of)

2017-06-15

Highlights: • A couple of algorithms to diagnose if Electron Cyclotron Heating (ECH) power is deposited properly on the expected deposition minor radius are proposed. • The algorithms are based on Bayesian theory and Fuzzy logic. • The algorithms are tested on the off-line experimental data acquired from Frascati Tokamak Upgrade (FTU), Frascati, Italy. • Uncertainties and evidences derived from the combination of online information formed by the measured diagnostic data and the prior information are also estimated. - Abstract: In the thermonuclear fusion systems, the new plasma control systems use some measured on-line information acquired from different sensors and prior information obtained by predictive plasma models in order to stabilize magnetic hydro dynamics (MHD) activity in a tokamak. Suppression of plasma instabilities is a key issue to improve the confinement time of controlled thermonuclear fusion with tokamaks. This paper proposes a couple of algorithms based on Bayesian theory and Fuzzy logic to diagnose if Electron Cyclotron Heating (ECH) power is deposited properly on the expected deposition minor radius (r{sub DEP}). Both algorithms also estimate uncertainties and evidences derived from the combination of the online information formed by the measured diagnostic data and the prior information. The algorithms have been employed on a set of off-line ECE channels data which have been acquired from the experimental shot number 21364 at Frascati Tokamak Upgrade (FTU), Frascati, Italy.

Stoichiometry control of complex oxides by sequential pulsed-laser deposition from binary-oxide targets

Energy Technology Data Exchange (ETDEWEB)

Herklotz, A. [ORNL, Materials Science and Technology Division, Bethel Valley Road, Oak Ridge, Tennessee 37831-6056 (United States); Martin Luther University Halle-Wittenberg, Institute for Physics, Von-Danckelmann-Platz 3, 06120 Halle (Germany); Dörr, K. [Martin Luther University Halle-Wittenberg, Institute for Physics, Von-Danckelmann-Platz 3, 06120 Halle (Germany); Ward, T. Z.; Eres, G. [ORNL, Materials Science and Technology Division, Bethel Valley Road, Oak Ridge, Tennessee 37831-6056 (United States); Christen, H. M.; Biegalski, M. D. [ORNL, Center for Nanophase Materials Sciences, Bethel Valley Road, Oak Ridge, Tennessee 37831-6496 (United States)

2015-03-30

To have precise atomic layer control over interfaces, we examine the growth of complex oxides through the sequential deposition from binary targets by pulsed laser deposition. In situ reflection high-energy electron diffraction (RHEED) is used to control the growth and achieve films with excellent structural quality. The growth from binary oxide targets is fundamentally different from single target growth modes and shows more similarities to shuttered growth by molecular beam epitaxy. The RHEED intensity oscillations of non-stoichiometric growth are consistent with a model of island growth and accumulation of excess material on the surface that can be utilized to determine the correct stoichiometry for growth. Correct monolayer doses can be determined through an envelope frequency in the RHEED intensity oscillations. In order to demonstrate the ability of this growth technique to create complex heterostructures, the artificial n = 2 and 3 Sr{sub n+1}Ti{sub n}O{sub 3n+1} Ruddlesden-Popper phases are grown with good long-range order. This method enables the precise unit-cell level control over the structure of perovskite-type oxides, and thus the growth of complex materials with improved structural quality and electronic functionality.

UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

Directory of Open Access Journals (Sweden)

Saita M

2016-01-01

Full Text Available Makiko Saita,1 Takayuki Ikeda,1,2 Masahiro Yamada,1,3 Katsuhiko Kimoto,4 Masaichi Chang-Il Lee,5 Takahiro Ogawa1 1Division of Advanced Prosthodontics, Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA, USA; 2Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Yokosuka, Japan; 3Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Miyagi, Japan; 4Department of Prosthodontics and Oral Rehabilitation, 5Yokosuka-Shonan Disaster Health Emergency Research Center and ESR Laboratories, Kanagawa Dental University Graduate School of Dentistry, Yokosuka, Japan Background: Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability.Methods and results: Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light were immersed in simulated body fluid (SBF for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition

Factors Controlling Black Carbon Deposition in Snow in the Arctic

Science.gov (United States)

Qi, L.; Li, Q.; He, C.; Li, Y.

2015-12-01

This study evaluates the sensitivity of black carbon (BC) concentration in snow in the Arctic to BC emissions, dry deposition and wet scavenging efficiency using a 3D global chemical transport model GEOS-Chem driven by meteorological field GEOS-5. With all improvements, simulated median BC concentration in snow agrees with observation (19.2 ng g-1) within 10%, down from -40% in the default GEOS-Chem. When the previously missed gas flaring emissions (mainly located in Russia) are included, the total BC emission in the Arctic increases by 70%. The simulated BC in snow increases by 1-7 ng g-1, with the largest improvement in Russia. The discrepancy of median BC in snow in the whole Arctic reduces from -40% to -20%. In addition, recent measurements of BC dry deposition velocity suggest that the constant deposition velocity of 0.03 cm s-1 over snow and ice used in the GEOS-Chem is too low. So we apply resistance-in-series method to calculate the dry deposition velocity over snow and ice and the resulted dry deposition velocity ranges from 0.03 to 0.24 cm s-1. However, the simulated total BC deposition flux in the Arctic and BC in snow does not change, because the increased dry deposition flux has been compensated by decreased wet deposition flux. However, the fraction of dry deposition to total deposition increases from 16% to 25%. This may affect the mixing of BC and snow particles and further affect the radative forcing of BC deposited in snow. Finally, we reduced the scavenging efficiency of BC in mixed-phase clouds to account for the effect of Wegener-Bergeron-Findeisen (WBF) process based on recent observations. The simulated BC concentration in snow increases by 10-100%, with the largest increase in Greenland (100%), Tromsø (50%), Alaska (40%), and Canadian Arctic (30%). Annual BC loading in the Arctic increases from 0.25 to 0.43 mg m-2 and the lifetime of BC increases from 9.2 to 16.3 days. This indicates that BC simulation in the Arctic is really sensitive to

High variability of the heterogeneous ice nucleation potential of oxalic acid dihydrate and sodium oxalate

Directory of Open Access Journals (Sweden)

R. Wagner

2010-08-01

Full Text Available The heterogeneous ice nucleation potential of airborne oxalic acid dihydrate and sodium oxalate particles in the deposition and condensation mode has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 244 and 228 K. Previous laboratory studies have highlighted the particular role of oxalic acid dihydrate as the only species amongst a variety of other investigated dicarboxylic acids to be capable of acting as a heterogeneous ice nucleus in both the deposition and immersion mode. We could confirm a high deposition mode ice activity for 0.03 to 0.8 μm sized oxalic acid dihydrate particles that were either formed by nucleation from a gaseous oxalic acid/air mixture or by rapid crystallisation of highly supersaturated aqueous oxalic acid solution droplets. The critical saturation ratio with respect to ice required for deposition nucleation was found to be less than 1.1 and the size-dependent ice-active fraction of the aerosol population was in the range from 0.1 to 22%. In contrast, oxalic acid dihydrate particles that had crystallised from less supersaturated solution droplets and had been allowed to slowly grow in a supersaturated environment from still unfrozen oxalic acid solution droplets over a time period of several hours were found to be much poorer heterogeneous ice nuclei. We speculate that under these conditions a crystal surface structure with less-active sites for the initiation of ice nucleation was generated. Such particles partially proved to be almost ice-inactive in both the deposition and condensation mode. At times, the heterogeneous ice nucleation ability of oxalic acid dihydrate significantly changed when the particles had been processed in preceding cloud droplet activation steps. Such behaviour was also observed for the second investigated species, namely sodium oxalate. Our experiments address the atmospheric scenario

High variability of the heterogeneous ice nucleation potential of oxalic acid dihydrate and sodium oxalate

Science.gov (United States)

Wagner, R.; Möhler, O.; Saathoff, H.; Schnaiter, M.; Leisner, T.

2010-08-01

The heterogeneous ice nucleation potential of airborne oxalic acid dihydrate and sodium oxalate particles in the deposition and condensation mode has been investigated by controlled expansion cooling cycles in the AIDA aerosol and cloud chamber of the Karlsruhe Institute of Technology at temperatures between 244 and 228 K. Previous laboratory studies have highlighted the particular role of oxalic acid dihydrate as the only species amongst a variety of other investigated dicarboxylic acids to be capable of acting as a heterogeneous ice nucleus in both the deposition and immersion mode. We could confirm a high deposition mode ice activity for 0.03 to 0.8 μm sized oxalic acid dihydrate particles that were either formed by nucleation from a gaseous oxalic acid/air mixture or by rapid crystallisation of highly supersaturated aqueous oxalic acid solution droplets. The critical saturation ratio with respect to ice required for deposition nucleation was found to be less than 1.1 and the size-dependent ice-active fraction of the aerosol population was in the range from 0.1 to 22%. In contrast, oxalic acid dihydrate particles that had crystallised from less supersaturated solution droplets and had been allowed to slowly grow in a supersaturated environment from still unfrozen oxalic acid solution droplets over a time period of several hours were found to be much poorer heterogeneous ice nuclei. We speculate that under these conditions a crystal surface structure with less-active sites for the initiation of ice nucleation was generated. Such particles partially proved to be almost ice-inactive in both the deposition and condensation mode. At times, the heterogeneous ice nucleation ability of oxalic acid dihydrate significantly changed when the particles had been processed in preceding cloud droplet activation steps. Such behaviour was also observed for the second investigated species, namely sodium oxalate. Our experiments address the atmospheric scenario that coating layers

FURNACE INJECTION OF ALKALINE SORBENTS FOR SULFURIC ACID CONTROL; SEMIANNUAL

International Nuclear Information System (INIS)

Gary M. Blythe

2002-01-01

This document summarizes progress on Cooperative Agreement DE-FC26-99FT40718, Furnace Injection of Alkaline Sorbents for Sulfuric Acid Control, during the time period October 1, 2001 through March 31, 2002. The objective of this project is to demonstrate the use of alkaline reagents injected into the furnace of coal-fired boilers as a means of controlling sulfuric acid emissions. The coincident removal of hydrochloric acid and hydrofluoric acid is also being determined, as is the removal of arsenic, a known poison for NO(sub X) selective catalytic reduction (SCR) catalysts. EPRI, the Tennessee Valley Authority (TVA), FirstEnergy Corporation, American Electric Power (AEP) and the Dravo Lime Company are project co-funders. URS Corporation is the prime contractor. This is the fifth reporting period for the subject Cooperative Agreement. During the previous (fourth) period, two long-term sorbent injection tests were conducted, one on Unit 3 at FirstEnergy's Bruce Mansfield Plant (BMP) and one on Unit 1 at AEP's Gavin Plant. Those tests determined the effectiveness of injecting alkaline slurries into the upper furnace of the boiler as a means of controlling sulfuric acid emissions from these units. The alkaline slurries tested included commercially available magnesium hydroxide slurry (Gavin Plant) and a byproduct magnesium hydroxide slurry (at both Gavin and BMP). The tests showed that injecting either the commercial or the byproduct magnesium hydroxide slurry could achieve up to 70-75% overall sulfuric acid removal. At BMP, the overall removal was limited by the need to maintain acceptable electrostatic precipitator (ESP) particulate control performance. At Gavin Plant, the overall sulfuric acid removal was limited because the furnace injected sorbent was less effective at removing SO(sub 3) formed across the SCR system installed on the unit for NO(sub X) control than at removing SO(sub 3) formed in the furnace. The SO(sub 3) removal results were presented in the

The effects of acid perturbation on a controlled ecosystem

Energy Technology Data Exchange (ETDEWEB)

Kollig, H.P.; Hall, T.L.

1982-02-01

Duplicate, 8-compartment, continuous-flow microcosms were used to study the effects of acid addition on community function, algal community structure, and degradation of a plasticizer, diethyl phthalate. Inputs of HCl decreased the alkalinity (measured as CaCO/sub 3/) from 25 to 8 mgl/sup -1/, creating diurnal H/sup +/ activity curves that indicated that the ecosystem was being severely stressed. Removal of excess acid was accompanied by a return to a normal diurnal pH cycle. Nutrient concentrations and 0/sub 2/ production did not give a definite indication of stress resulting from the addition of acid. Algal community structure and total biomass were not affected by acid inputs. Also, degradation rates of diethyl phtalate by the aquatic bacteria were similar for the control and the acid-stressed systems. These studies indicate that acid inputs can significantly disrupt normal ecosystem function, such as diurnal pH cycling, without having a measurable impact on other parameters usually monitored in aquatic ecosystems.

Ionically Paired Layer-by-Layer Hydrogels: Water and Polyelectrolyte Uptake Controlled by Deposition Time

Directory of Open Access Journals (Sweden)

Victor Selin

2018-01-01

Full Text Available Despite intense recent interest in weakly bound nonlinear (“exponential” multilayers, the underlying structure-property relationships of these films are still poorly understood. This study explores the effect of time used for deposition of individual layers of nonlinearly growing layer-by-layer (LbL films composed of poly(methacrylic acid (PMAA and quaternized poly-2-(dimethylaminoethyl methacrylate (QPC on film internal structure, swelling, and stability in salt solution, as well as the rate of penetration of invading polyelectrolyte chains. Thicknesses of dry and swollen films were measured by spectroscopic ellipsometry, film internal structure—by neutron reflectometry (NR, and degree of PMAA ionization—by Fourier-transform infrared spectroscopy (FTIR. The results suggest that longer deposition times resulted in thicker films with higher degrees of swelling (up to swelling ratio as high as 4 compared to dry film thickness and stronger film intermixing. The stronger intermixed films were more swollen in water, exhibited lower stability in salt solutions, and supported a faster penetration rate of invading polyelectrolyte chains. These results can be useful in designing polyelectrolyte nanoassemblies for biomedical applications, such as drug delivery coatings for medical implants or tissue engineering matrices.

Distribution of soil selenium in China is potentially controlled by deposition and volatilization?

Science.gov (United States)

Sun, Guo-Xin; Meharg, Andrew A.; Li, Gang; Chen, Zheng; Yang, Lei; Chen, Song-Can; Zhu, Yong-Guan

2016-02-01

Elucidating the environmental drivers of selenium (Se) spatial distribution in soils at a continental scale is essential to better understand it’s biogeochemical cycling to improve Se transfer into diets. Through modelling Se biogeochemistry in China we found that deposition and volatilization are key factors controlling distribution in surface soil, rather than bedrock-derived Se (balance in other terrestrial environments worldwide.

Engineering strategies aimed at control of acidification rate of lactic acid bacteria

DEFF Research Database (Denmark)

Martinussen, Jan; Solem, Christian; Holm, Anders Koefoed

2013-01-01

The ability of lactic acid bacteria to produce lactic acid from various sugars plays an important role in food fermentations. Lactic acid is derived from pyruvate, the end product of glycolysis and thus a fast lactic acid production rate requires a high glycolytic flux. In addition to lactic acid......, alternative end products - ethanol, acetic acid and formic acid - are formed by many species. The central role of glycolysis in lactic acid bacteria has provoked numerous studies aiming at identifying potential bottleneck(s) since knowledge about flux control could be important not only for optimizing food...

Modelling impacts of atmospheric deposition and temperature on long-term DOC trends.

Science.gov (United States)

Sawicka, K; Rowe, E C; Evans, C D; Monteith, D T; E I Vanguelova; Wade, A J; J M Clark

2017-02-01

It is increasingly recognised that widespread and substantial increases in Dissolved organic carbon (DOC) concentrations in remote surface, and soil, waters in recent decades are linked to declining acid deposition. Effects of rising pH and declining ionic strength on DOC solubility have been proposed as potential dominant mechanisms. However, since DOC in these systems is derived mainly from recently-fixed carbon, and since organic matter decomposition rates are considered sensitive to temperature, uncertainty persists over the extent to which other drivers that could influence DOC production. Such potential drivers include fertilisation by nitrogen (N) and global warming. We therefore ran the dynamic soil chemistry model MADOC for a range of UK soils, for which time series data are available, to consider the likely relative importance of decreased deposition of sulphate and chloride, accumulation of reactive N, and higher temperatures, on soil DOC production in different soils. Modelled patterns of DOC change generally agreed favourably with measurements collated over 10-20years, but differed markedly between sites. While the acidifying effect of sulphur deposition appeared to be the predominant control on the observed soil water DOC trends in all the soils considered other than a blanket peat, the model suggested that over the long term, the effects of nitrogen deposition on N-limited soils may have been sufficient to raise the "acid recovery DOC baseline" significantly. In contrast, reductions in non-marine chloride deposition and effects of long term warming appeared to have been relatively unimportant. The suggestion that future DOC concentrations might exceed preindustrial levels as a consequence of nitrogen pollution has important implications for drinking water catchment management and the setting and pursuit of appropriate restoration targets, but findings still require validation from reliable centennial-scale proxy records, such as those being developed

Characterization and temperature controlling property of TiAlN coatings deposited by reactive magnetron co-sputtering

International Nuclear Information System (INIS)

Chen, J.T.; Wang, J.; Zhang, F.; Zhang, G.A.; Fan, X.Y.; Wu, Z.G.; Yan, P.X.

2009-01-01

Titanium aluminum nitride (TiAlN) ternary coating is a potential material which is expected to be applied on satellite for thermal controlling. In order to investigate thermal controlling property, TiAlN coatings were deposited on Si wafers with different N 2 and Ar flux ratio by reactive magnetron co-sputtering. The structure, morphology, chemical composition and optical reflectance are investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), atom force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and spectrophotometer, respectively. The orientation of the coatings depends on the N 2 /Ar flux ratio. The coatings deposited with N 2 /Ar ratio of 10, 30 and 60% show the cubic-TiN [2 2 0] preferred orientation and the coating deposited with N 2 /Ar ratio of 100% exhibits the phase of hexagonal-AlN and cubic-TiN. The surface of the coatings becomes more compact and smoother with the N 2 /Ar ratios increase. XPS spectrum indicates that the oxides (TiO 2 and Al 2 O 3 ), oxynitride (TiN x O y ) and nitrides (TiN and AlN x ) appear at the surface of the coatings. Ignoring internal power, the optimum equilibrium temperature of TiAlN coatings is 18 deg. C and the equilibrium temperature after heat-treated has slight change, which provides the prospective application on thermal controlling

Development of a Controlled Release of Salicylic Acid Loaded Stearic Acid-Oleic Acid Nanoparticles in Cream for Topical Delivery

Directory of Open Access Journals (Sweden)

J. O. Woo

2014-01-01

Full Text Available Lipid nanoparticles are colloidal carrier systems that have extensively been investigated for controlled drug delivery, cosmetic and pharmaceutical applications. In this work, a cost effective stearic acid-oleic acid nanoparticles (SONs with high loading of salicylic acid, was prepared by melt emulsification method combined with ultrasonication technique. The physicochemical properties, thermal analysis and encapsulation efficiency of SONs were studied. TEM micrographs revealed that incorporation of oleic acid induces the formation of elongated spherical particles. This observation is in agreement with particle size analysis which also showed that the mean particle size of SONs varied with the amount of OA in the mixture but with no effect on their zeta potential values. Differential scanning calorimetry analysis showed that the SONs prepared in this method have lower crystallinity as compared to pure stearic acid. Different amount of oleic acid incorporated gave different degree of perturbation to the crystalline matrix of SONs and hence resulted in lower degrees of crystallinity, thereby improving their encapsulation efficiencies. The optimized SON was further incorporated in cream and its in vitro release study showed a gradual release for 24 hours, denoting the incorporation of salicylic acid in solid matrix of SON and prolonging the in vitro release.

Interaction of tectonic and depositional processes that control the evolution of the Iberian Gulf of Cadiz margin

Science.gov (United States)

Maldonado, A.; Nelson, C.H.

1999-01-01

This study provides an integrated view of the growth patterns and factors that controlled the evolution of the Gulf of Cadiz continental margin based on studies of the tectonic, sedimentologic and oceanographic history of the area. Seven sedimentary regimes are identified, but there are more extensive descriptions of the late Cenozoic regimes because of the larger data base. The regimes of the Mesozoic passive margin include carbonate platforms, which become mixed calcareous-terrigenous deposits during the Late Cretaceous-early Tertiary. The Oligocene and Early Miocene terrigenous regimes developed, in contrast, over the active and transcurrent margins near the African-Iberian plate boundary. The top of the Gulf of Cadiz olistostrome, emplaced in the Late Miocene, is used as a key horizon to define the 'post-orogenic' depositional regimes. The Late Miocene progradational margin regime is characterized by a large terrigenous sediment supply to the margin and coincides with the closing of the Miocene Atlantic-Mediterranean gateways. The terrigenous drift depositional regime of the Early Pliocene resulted from the occurrence of high eustatic sea level and the characteristics of the Mediterranean outflow currents that developed after the opening of the Strait of Gibraltar. The Late Pliocene and Quaternary regimes are dominated by sequences of deposits related to cycles of high and low sea levels. Deposition of shelf-margin deltas and slope wedges correlate with regressive and low sea level regimes caused by eustasy and subsidence. During the highstand regimes of the Holocene, inner shelf prograding deltas and deep-water sediment drifts were developed under the influence of the Atlantic inflow and Mediterranean outflow currents, respectively. A modern human cultural regime began 2000 years ago with the Roman occupation of Iberia; human cultural effects on sedimentary regimes may have equalled natural factors such as climate change. Interplay of tectonic and

Early diagenesis of recently deposited organic matter: A 9-yr time-series study of a flood deposit

Science.gov (United States)

Tesi, T.; Langone, L.; Goñi, M. A.; Wheatcroft, R. A.; Miserocchi, S.; Bertotti, L.

2012-04-01

In Fall 2000, the Po River (Italy) experienced a 100-yr return period flood that resulted in a 1-25 cm-thick deposit in the adjacent prodelta (10-25 m water depth). In the following years, numerous post-depositional perturbations occurred including bioturbation, reworking by waves with heights exceeding 5 m, as well as periods of extremely high and low sediment supply. Cores collected in the central prodelta after the Fall 2000 flood and over the following 9 yr, allowed characterization of the event-strata in their initial state and documentation of their subsequent evolution. Sedimentological characteristics were investigated using X-radiographs and sediment texture analyses, whereas the composition of sedimentary organic matter (OM) was studied via bulk and biomarker analyses, including organic carbon (OC), total nitrogen (TN), carbon stable isotope composition (δ13C), lignin phenols, cutin-products, p-hydroxy benzenes, benzoic acids, dicarboxylic acids, and fatty acids. The 9-yr time-series analysis indicated that roughly the lower half of the original event bed was preserved in the sediment record. Conversely, the upper half of the deposit experienced significant alterations including bioturbation, addition of new material, as well as coarsening. Comparison of the recently deposited material with 9-yr old preserved strata represented a unique natural laboratory to investigate the diagenesis of sedimentary OM in a non-steady system. Bulk data indicated that OC and TN were degraded at similar rates (loss ∼17%) whereas biomarkers exhibited a broad spectrum of reactivities (loss from ∼6% to ∼60%) indicating selective preservation during early diagenesis. Given the relevance of episodic sedimentation in several margins, this study has demonstrated the utility of event-response and time-series sampling of the seabed for understanding the early diagenesis in non-steady conditions.

Topographic controls on pyroclastic density current dynamics: Insight from 18 May 1980 deposits at Mount St. Helens, Washington (USA)

Science.gov (United States)

Brand, Brittany D.; Bendaña, Sylvana; Self, Stephen; Pollock, Nicholas

2016-07-01

Our ability to interpret the deposits of pyroclastic density currents (PDCs) is critical for understanding the transport and depositional processes that control PDC dynamics. This paper focuses on the influence of slope on flow dynamics and criticality as recorded in PDC deposits from the 18 May 1980 eruption of Mt. St. Helens (USA). PDC deposits are found along the steep flanks (10°-30°) and across the pumice plain ( 5°) up to 8 km north of the volcano. Granulometry, componentry and descriptions of depositional characteristics (e.g., bedform morphology) are recorded with distance from source. The pumice plain deposits are primarily thick (3-12 m), massive and poorly-sorted, and represent deposition from a series of concentrated PDCs. By contrast, the steep flank deposits are stratified to cross-stratified, suggesting deposition from PDCs where turbulence strongly influenced transport and depositional processes. We propose that acceleration of the concentrated PDCs along the steep flanks resulted in thinning of the concentrated, basal region of the current(s). Enhanced entrainment of ambient air, and autofluidization from upward fluxes of air from substrate interstices and plunging breakers across rugged, irregular topography further inflated the currents to the point that the overriding turbulent region strongly influenced transport and depositional mechanisms. Acceleration in combination with partial confinement in slot canyons and high surface roughness would also increase basal shear stress, further promoting shear and traction transport in the basal region of the current. Conditions along the steep flank resulted in supercritical flow, as recorded by regressive bedforms, which gradually transitioned to subcritical flow downstream as the concentrated basal region thickness increased as a function of decreasing slope and flow energy. We also find that (1) PDCs were erosive into the underlying granular substrate along high slopes (> 25°) where currents were

Large Area Deposition of MoS2 by Pulsed Laser Deposition with In-Situ Thickness Control

KAUST Repository

Serna, Martha I.

2016-05-24

A scalable and catalyst-free method to deposit stoichiometric Molybdenum Disulfide (MoS2) films over large areas is reported with the maximum area limited by the size of the substrate holder. The method allows deposition of MoS2 layers on a wide range of substrates without any additional surface preparation including single crystals (sapphire and quartz), polycrystalline (HfO2), and amorphous (SiO2). The films are deposited using carefully designed MoS2 targets fabricated with excess of sulfur (S) and variable MoS2 and S particle size. Uniform and layered MoS2 films as thin as two monolayers, with an electrical resistivity of 1.54 × 104 Ω cm-1 were achieved. The MoS2 stoichiometry was as confirmed by High Resolution Rutherford Backscattering Spectrometry (HRRBS). With the method reported here, in situ graded MoS2 films ranging from ~1 to 10 monolayers can also be deposited.

Large Area Deposition of MoS2 by Pulsed Laser Deposition with In-Situ Thickness Control

KAUST Repository

Serna, Martha I.; Yoo, Seong H.; Moreno, Salvador; Xi, Yang; Oviedo, Juan Pablo; Choi, Hyunjoo; Alshareef, Husam N.; Kim, Moon J.; Minary-Jolandan, Majid; Quevedo-Lopez, Manuel A.

2016-01-01

A scalable and catalyst-free method to deposit stoichiometric Molybdenum Disulfide (MoS2) films over large areas is reported with the maximum area limited by the size of the substrate holder. The method allows deposition of MoS2 layers on a wide range of substrates without any additional surface preparation including single crystals (sapphire and quartz), polycrystalline (HfO2), and amorphous (SiO2). The films are deposited using carefully designed MoS2 targets fabricated with excess of sulfur (S) and variable MoS2 and S particle size. Uniform and layered MoS2 films as thin as two monolayers, with an electrical resistivity of 1.54 × 104 Ω cm-1 were achieved. The MoS2 stoichiometry was as confirmed by High Resolution Rutherford Backscattering Spectrometry (HRRBS). With the method reported here, in situ graded MoS2 films ranging from ~1 to 10 monolayers can also be deposited.

Microstructural control over soluble pentacene deposited by capillary pen printing for organic electronics.

Science.gov (United States)

Lee, Wi Hyoung; Min, Honggi; Park, Namwoo; Lee, Junghwi; Seo, Eunsuk; Kang, Boseok; Cho, Kilwon; Lee, Hwa Sung

2013-08-28

Research into printing techniques has received special attention for the commercialization of cost-efficient organic electronics. Here, we have developed a capillary pen printing technique to realize a large-area pattern array of organic transistors and systematically investigated self-organization behavior of printed soluble organic semiconductor ink. The capillary pen-printed deposits of organic semiconductor, 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS_PEN), was well-optimized in terms of morphological and microstructural properties by using ink with mixed solvents of chlorobenzene (CB) and 1,2-dichlorobenzene (DCB). Especially, a 1:1 solvent ratio results in the best transistor performances. This result is attributed to the unique evaporation characteristics of the TIPS_PEN deposits where fast evaporation of CB induces a morphological evolution at the initial printed position, and the remaining DCB with slow evaporation rate offers a favorable crystal evolution at the pinned position. Finally, a large-area transistor array was facilely fabricated by drawing organic electrodes and active layers with a versatile capillary pen. Our approach provides an efficient printing technique for fabricating large-area arrays of organic electronics and further suggests a methodology to enhance their performances by microstructural control of the printed organic semiconducting deposits.

Sulfur accumulation and atmospherically deposited sulfate in the Lake States.

Science.gov (United States)

Mark B. David; George Z. Gernter; David F. Grigal; Lewis F. Ohmann

1989-01-01

Characterizes the mass of soil sulfur (adjusted for nitrogen), and atmospherically deposited sulfate along an acid precipitation gradient from Minnesota to Michigan. The relationship of these variables, presented graphically through contour mapping, suggests that patterns of atmospheric wet sulfate deposition are reflected in soil sulfur pools.

Hyper-thermal acid hydrolysis and adsorption treatment of red seaweed, Gelidium amansii for butyric acid production with pH control.

Science.gov (United States)

Ra, Chae Hun; Jeong, Gwi-Taek; Kim, Sung-Koo

2017-03-01

Optimal hyper-thermal (HT) acid hydrolysis conditions for Gelidium amansii were determined to be 12% (w/v) seaweed slurry content and 144 mM H 2 SO 4 at 150 °C for 10 min. HT acid hydrolysis-treated G. amansii hydrolysates produced low concentrations of inhibitory compounds and adsorption treatment using 3% activated carbon. An adsorption time of 5 min was subsequently used to remove the inhibitory 5-hydroxymethylfurfural from the medium. A final maximum monosaccharide concentration of 44.6 g/L and 79.1% conversion from 56.4 g/L total fermentable monosaccharides with 120 g dw/L G. amansii slurry was obtained from HT acid hydrolysis, enzymatic saccharification, and adsorption treatment. This study demonstrates the potential for butyric acid production from G. amansii hydrolysates under non-pH-controlled as well as pH-controlled fermentation using Clostridium acetobutylicum KCTC 1790. The activated carbon treatment and pH-controlled fermentation showed synergistic effects and produced butyric acid at a concentration of 11.2 g/L after 9 days of fermentation.

Progress Toward Meeting NIF Specifications for Vapor Deposited Polyimide Ablator Coatings

International Nuclear Information System (INIS)

Letts, Stephan A.; Anthamatten, Mitchell; Buckley, Steven R.; Fearon, Evelyn; Nissen, April E.H.; Cook, Robert C.

2004-01-01

We are developing an evaporative coating technique for deposition of thick polyimide (PI) ablator layers on ICF targets. The PI coating technique utilizes stoichiometrically controlled fluxes from two Knudsen cell evaporators containing a dianhydride and a diamine to deposit a polyamic acid (PAA) coating. Heating the PAA coating to 300 deg. C converts the PAA coating to a polyimide. Coated shells are rough due to particles on the substrate mandrels and from damage to the coating caused by the agitation used to achieve a uniform coating. We have developed a smoothing process that exposes an initially rough PAA coated shell to solvent vapor using gas levitation. We found that after smoothing the coatings developed a number of wide (low-mode) defects. We have identified two major contributors to low-mode roughness: surface hydrolysis, and deformation during drying/curing. By minimizing air exposure prior to vapor smoothing, avoiding excess solvent sorption during vapor smoothing, and using slow drying we are able to deposit and vapor smooth coatings 160 μm thick with a surface roughness less than 20 nm RMS

Dietary High-Oleic Acid Soybean Oil Dose Dependently Attenuates Egg Yolk Content of n-3 Polyunsaturated Fatty Acids in Laying Hens Fed Supplemental Flaxseed Oil.

Science.gov (United States)

Elkin, Robert G; Kukorowski, Alexandra N; Ying, Yun; Harvatine, Kevin J

2018-02-01

Chickens can hepatically synthesize eicosapentaenoic acid (20:5 n-3) and docosahexaenoic acid (22:6 n-3) from α-linolenic acid (ALA; 18:3 n-3); however, the process is inefficient and competitively inhibited by dietary linoleic acid (LNA; 18:2 n-6). In the present study, the influence of dietary high-oleic acid (OLA; 18:1 n-9) soybean oil (HOSO) on egg and tissue deposition of ALA and n-3 polyunsaturated fatty acids (PUFA) synthesized from dietary ALA was investigated in laying hens fed a reduced-LNA base diet supplemented with high-ALA flaxseed oil (FLAX). We hypothesized that reducing the dietary level of LNA would promote greater hepatic conversion of ALA to very long-chain (VLC; >20C) n-3 PUFA, while supplemental dietary HOSO would simultaneously further enrich eggs with OLA without influencing egg n-3 PUFA contents. Nine 51-week-old hens each were fed 0, 10, 20, or 40 g HOSO/kg diet for 12 weeks. Within each group, supplemental dietary FLAX was increased every 3 weeks from 0 to 10 to 20 to 40 g/kg diet. Compared to controls, dietary FLAX maximally enriched the total n-3 and VLC n-3 PUFA contents in egg yolk by 9.4-fold and 2.2-fold, respectively, while feeding hens 40 g HOSO/kg diet maximally attenuated the yolk deposition of ALA, VLC n-3 PUFA, and total n-3 PUFA by 37, 15, and 32%, respectively. These results suggest that dietary OLA is not neutral with regard to the overall process by which dietary ALA is absorbed, metabolized, and deposited into egg yolk, either intact or in the form of longer-chain/more unsaturated n-3 PUFA derivatives. © 2018 AOCS.

Deposition of SrTiO3 films by electrophoresis with thickness and particle size control

International Nuclear Information System (INIS)

Junior, W.D.M.; Pena, A.F.V.; Souza, A.E.; Santos, G.T.A.; Teixeira, S.R.; Senos, A.M.R.; Longo, E.

2012-01-01

The SrTiO3 (ST) is a material that exhibits semiconducting characteristics and interesting electrical properties. In room temperature has a structure of high cubic symmetry. The size of the crystallites of this material directly influences this symmetry, changing its network parameters. ST nanoparticles are obtained by hydrothermal method assisted by microwave (MAH). ST films are prepared by electrophoretic deposition (EPD). Approximately 1 g of the powder is dissolved in 100 ml of acetone and 1.5 ml of triethanolamine. The stainless steel substrates are arranged horizontally in the solution. The depositions are performed for 1-10 min and subjected to a potential difference of 20-100 V. The films were characterized by x-ray diffraction (XRD) and atomic force microscopy (AFM). The characterizations show that it is possible to control both the thickness and size of the crystallites of the film depending on the deposition parameters adopted. (author)

Structure Of Conduits Of The Acidic Volcanism And Related Deposits In The Paraná-Etendeka Magmatic Province, São Marcos Region, South Brazil

Science.gov (United States)

Guimarães, L. F.; De Campos, C. P.; Lima, E. F. D.; Janasi, V. A.

2015-12-01

Voluminous acidic volcanics from the Paraná-Etendeka Magmatic Province crop out in the southern part of Brazil. The conduits responsible for the feeding of this intermediate/acid volcanism are preserved and well exposed in the São Marcos region (Lima et al. 2012; Geologia USP 12:49-64). Conduits are aligned along a NW-SE trend and have thicknesses up to 1 km. These structures are often characterized by mixing between dacitic and rhyodacitic magmas, with intercalation between two major zones: 1) reddish or grayish vitrophiricdacite/rhyodacite, sub-divided in massive or vesiculated; 2) reddish or grayish vitrophiric fragmented dacite/rhyodacite composed of bubble-rich angular to rounded blocks. Such fragments commonly deform coeval to the flow. A third zone dominated by filaments depicts a chaotic stretching-and-folding process from the mixture of the acid magmas. We used classical field measurements of flow structures and recognized main flow directions in these feeder-dikes. They follow two preferential directions: NW, ranging from N272° to N 355°, and NE, varying from N20° to N85°. These directions are indicative of a transtensive fissural system, which seems to be related to conjugated fractures. Evidence of an important fragmentation process in the conduits point towards the presence of related products in this region, thus rheomorphic deposits such as those observed elsewhere (e.g. Uruguay and Namibia) are expected to occur. Possible vestiges of these deposits could be represented by restricted outcrops of lens-shaped and banded hipohyaline, occasionally bubble-rich, dacites. The presence of continuous pseudotachylitic levels, tightly folded bands with horizontal axial planes together with local deformed bubble-rich pumice-like lens could be indicative of remelting and rheomorphism of previous vulcanoclastic material. Coulees and compound (lobed) dacitic lava flows, reaching up to 5-8 meters length, occur as the uppermost deposits and correspond to the

Controlled overproduction of proteins by lactic acid bacteria

NARCIS (Netherlands)

Kuipers, Oscar P.; Ruyter, Pascalle G.G.A. de; Kleerebezem, Michiel; Vos, Willem M. de

1997-01-01

Lactic acid bacteria are widely used in industrial food fermentations, contributing to flavour, texture and preservation of the fermented products. Here we describe recent advances in the development of controlled gene expression systems, which allow the regulated overproduction of any desirable

Co-Cu-Au deposits in metasedimentary rocks-A preliminary report

Science.gov (United States)

Slack, J.F.; Causey, J.D.; Eppinger, R.G.; Gray, J.E.; Johnson, C.A.; Lund, K.I.; Schulz, K.J.

2010-01-01

A compilation of data on global Co-Cu-Au deposits in metasedimentary rocks refines previous descriptive models for their occurrence and provides important information for mineral resource assessments and exploration programs. This compilation forms the basis for a new classification of such deposits, which is speculative at this early stage of research. As defined herein, the Co-Cu-Au deposits contain 0.1 percent or more by weight of Co in ore or mineralized rock, comprising disseminated to semi-massive Co-bearing sulfide minerals with associated Fe- and Cu-bearing sulfides, and local gold, concentrated predominantly within rift-related, siliciclastic metasedimentary rocks of Proterozoic age. Some deposits have appreciable Ag ? Bi ? W ? Ni ? Y ? rare earth elements ? U. Deposit geometry includes stratabound and stratiform layers, lenses, and veins, and (or) discordant veins and breccias. The geometry of most deposits is controlled by stratigraphic layering, folds, axial-plane cleavage, shear zones, breccias, or faults. Ore minerals are mainly cobaltite, skutterudite, glaucodot, and chalcopyrite, with minor gold, arsenopyrite, pyrite, pyrrhotite, bismuthinite, and bismuth; some deposits have appreciable tetrahedrite, uraninite, monazite, allanite, xenotime, apatite, scheelite, or molybdenite. Magnetite can be abundant in breccias, veins, or stratabound lenses within ore or surrounding country rocks. Common gangue minerals include quartz, biotite, muscovite, K-feldspar, albite, chlorite, and scapolite; many deposits contain minor to major amounts of tourmaline. Altered wall rocks generally have abundant biotite or albite. Mesoproterozoic metasedimentary successions constitute the predominant geologic setting. Felsic and (or) mafic plutons are spatially associated with many deposits and at some localities may be contemporaneous with, and involved in, ore formation. Geoenvironmental data for the Blackbird mining district in central Idaho indicate that weathering of

Acid precipitation literature review

Energy Technology Data Exchange (ETDEWEB)

Seip, H M; Andersen, B; Andersson, G; Hov, Oe; Kucera, V; Moseholm, L

1986-01-01

There is an increasing number of publications on acid deposition and related phenomena. Interest in these topics has also been reflected in a considerable number of meetings and conferences in this field. The largest of these in 1985 was the ''International Symposium on Acidic Precipitation'' (Muskoka, Ontario). Most work so far has been carried out in North America and Europe. There is, however, an increasing interest in obtaining a better picture of sensitive areas and possible acidification in other parts of the world. Anthropogenic SO/sub 2/ emissions have been estimated to be (in TgSyr/sup -1/): 2.4 (Africa), 4.1 (South America), 0.7 (Ocenia), and 18.3 (Asia). The largest increase during the last decade has been in Asia. Based on Studies of precipitation in remote areas it has been suggested that the natural background concentration for sulphate in many areas should be about 6 ..mu..eq 1/sup -1/. A new study of sulphate and nitrate in Greenland snow showed that both ions increased by a factor of about 2 from 1895 to 1978. The concentrations of SO/sub 2/ at Norwegian rural sites show a decreasing trend since late 1970s, while concentrations of sulphate in air show no clear trend. More reliable models for transformation, transport and deposition of chemicals are being developed, including three-dimensional grid models to describe episodes of elevated pollution levels lasting for a few days. Model calculations indicate that control of hydrocarbon (HC) emissions is much more efficient in reducing the ozone level in southern Scandinavia in episodes influenced by long-range transported pollutants than NO/sub x/ control of combined NO/sub x/ and HC control. 36 refs. (EG).

A new strategy to enhance polysialic acid production by controlling ...

African Journals Online (AJOL)

Polysialic acid (PSA) is a new pharmaceutical material used in control release of protein drugs and as scaffold material in biomedical applications. It is also a vital source of sialic acid and its derivatives. In this paper, we demonstrated that the substrate sorbitol has significant effect on bacterial growth and PSA formation in ...

Genetic mapping of QTLs controlling fatty acids provided insights into the genetic control of fatty acid synthesis pathway in peanut (Arachis hypogaea L..

Directory of Open Access Journals (Sweden)

Ming Li Wang

Full Text Available Peanut, a high-oil crop with about 50% oil content, is either crushed for oil or used as edible products. Fatty acid composition determines the oil quality which has high relevance to consumer health, flavor, and shelf life of commercial products. In addition to the major fatty acids, oleic acid (C18:1 and linoleic acid (C18:2 accounting for about 80% of peanut oil, the six other fatty acids namely palmitic acid (C16:0, stearic acid (C18:0, arachidic acid (C20:0, gadoleic acid (C20:1, behenic acid (C22:0, and lignoceric acid (C24:0 are accounted for the rest 20%. To determine the genetic basis and to improve further understanding on effect of FAD2 genes on these fatty acids, two recombinant inbred line (RIL populations namely S-population (high oleic line 'SunOleic 97R' × low oleic line 'NC94022' and T-population (normal oleic line 'Tifrunner' × low oleic line 'GT-C20' were developed. Genetic maps with 206 and 378 marker loci for the S- and the T-population, respectively were used for quantitative trait locus (QTL analysis. As a result, a total of 164 main-effect (M-QTLs and 27 epistatic (E-QTLs QTLs associated with the minor fatty acids were identified with 0.16% to 40.56% phenotypic variation explained (PVE. Thirty four major QTLs (>10% of PVE mapped on five linkage groups and 28 clusters containing more than three QTLs were also identified. These results suggest that the major QTLs with large additive effects would play an important role in controlling composition of these minor fatty acids in addition to the oleic and linoleic acids in peanut oil. The interrelationship among these fatty acids should be considered while breeding for improved peanut genotypes with good oil quality and desired fatty acid composition.

The Influence of Selected Fingerprint Enhancement Techniques on Forensic DNA Typing of Epithelial Cells Deposited on Porous Surfaces.

Science.gov (United States)

Tsai, Li-Chin; Lee, Cheng-Chang; Chen, Chun-Chieh; Lee, James Chun-I; Wang, Sheng-Meng; Huang, Nu-En; Linacre, Adrian; Hsieh, Hsing-Mei

2016-01-01

Fingerprints deposited at crime scene can be a source of DNA. Previous reports on the effects of fingerprint enhancement methods have focused mainly on fingermarks deposited in blood or saliva. Here, we evaluate the effects of fingerprint enhancement methods on fingerprints deposited on porous surfaces. We performed real-time quantification and STR typing, the results of which indicated that two methods (iodine fuming and 1,2-indanedione in ethyl acetate enhancement) had no effect on the quantity of DNA isolated and resultant STR alleles when compared to control samples. DNA quantities and allele numbers were lower for samples enhanced with silver nitrate and 1,2-indanedione in acetic acid when compared to control samples. Based on DNA quantity, quality, and observable stochastic effects, our data indicated that iodine fuming and 1,2-indanedione in ethyl acetate were the preferred options for the enhancement of fingerprints on porous surfaces. © 2015 American Academy of Forensic Sciences.

Multiple Acid Sensors Control Helicobacter pylori Colonization of the Stomach.

Science.gov (United States)

Huang, Julie Y; Goers Sweeney, Emily; Guillemin, Karen; Amieva, Manuel R

2017-01-01

Helicobacter pylori's ability to respond to environmental cues in the stomach is integral to its survival. By directly visualizing H. pylori swimming behavior when encountering a microscopic gradient consisting of the repellent acid and attractant urea, we found that H. pylori is able to simultaneously detect both signals, and its response depends on the magnitudes of the individual signals. By testing for the bacteria's response to a pure acid gradient, we discovered that the chemoreceptors TlpA and TlpD are each independent acid sensors. They enable H. pylori to respond to and escape from increases in hydrogen ion concentration near 100 nanomolar. TlpD also mediates attraction to basic pH, a response dampened by another chemoreceptor TlpB. H. pylori mutants lacking both TlpA and TlpD (ΔtlpAD) are unable to sense acid and are defective in establishing colonization in the murine stomach. However, blocking acid production in the stomach with omeprazole rescues ΔtlpAD's colonization defect. We used 3D confocal microscopy to determine how acid blockade affects the distribution of H. pylori in the stomach. We found that stomach acid controls not only the overall bacterial density, but also the microscopic distribution of bacteria that colonize the epithelium deep in the gastric glands. In omeprazole treated animals, bacterial abundance is increased in the antral glands, and gland colonization range is extended to the corpus. Our findings indicate that H. pylori has evolved at least two independent receptors capable of detecting acid gradients, allowing not only survival in the stomach, but also controlling the interaction of the bacteria with the epithelium.

Discrete deposition of hydroxyapatite nanoparticles on a titanium implant with predisposing substrate microtopography accelerated osseointegration

International Nuclear Information System (INIS)

Nishimura, Ichiro; Huang Yuhong; Butz, Frank; Ogawa, Takahiro; Lin, Audrey; Wang, Chiachien Jake

2007-01-01

We report here a new versatile method to deposit discrete hydroxyapatite (HA) nanoparticles on a titanium (Ti) implant with predisposing substrate microtopography, which exhibited an unexpectedly robust biological effect. Commercially pure Ti substrates were treated with 3-aminopropyltriethoxysilane, on which HA nanoparticles (20 nm) were deposited and chemically bonded to TiO 2 . The HA deposition rate was linearly related to the treatment time and HA nanoparticles were deposited on up to 50% of the substrate surface. As a result, the discrete deposition of HA nanoparticles generated novel 20-40 nm nanotopography on the Ti substrate with microtopography that was smooth (turned) or roughened by double acid etching (DAE). The experimental implants with or without HA nanoparticles were surgically placed in rat femur and an implant push-in test was performed after two weeks of healing. The deposition of HA nanoparticles on the DAE surface increased the mechanical withstanding load by 129% and 782% as compared to the control DAE and turned implants, respectively. Micro-computed tomography-based 3D bone morphometry revealed equivalent bone volumes around the DAE implant with or without HA nanoparticles. These data suggest that the discrete deposition of HA nanoparticles accelerates the early osseointegration process, likely through increased shear bonding strengths

Discrete deposition of hydroxyapatite nanoparticles on a titanium implant with predisposing substrate microtopography accelerated osseointegration

Energy Technology Data Exchange (ETDEWEB)

Nishimura, Ichiro [UCLA School of Dentistry, Weintraub Center for Reconstructive Biotechnology and Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, Los Angeles, CA (United States); Huang Yuhong [Chemat Technology, Incorporated, Northridge, CA (United States); Butz, Frank [UCLA School of Dentistry, Weintraub Center for Reconstructive Biotechnology and Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, Los Angeles, CA (United States); Ogawa, Takahiro [UCLA School of Dentistry, Weintraub Center for Reconstructive Biotechnology and Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, Los Angeles, CA (United States); Lin, Audrey [UCLA School of Dentistry, Weintraub Center for Reconstructive Biotechnology and Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, Los Angeles, CA (United States); Wang, Chiachien Jake [UCLA School of Dentistry, Weintraub Center for Reconstructive Biotechnology and Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, Los Angeles, CA (United States)

2007-06-20

We report here a new versatile method to deposit discrete hydroxyapatite (HA) nanoparticles on a titanium (Ti) implant with predisposing substrate microtopography, which exhibited an unexpectedly robust biological effect. Commercially pure Ti substrates were treated with 3-aminopropyltriethoxysilane, on which HA nanoparticles (20 nm) were deposited and chemically bonded to TiO{sub 2}. The HA deposition rate was linearly related to the treatment time and HA nanoparticles were deposited on up to 50% of the substrate surface. As a result, the discrete deposition of HA nanoparticles generated novel 20-40 nm nanotopography on the Ti substrate with microtopography that was smooth (turned) or roughened by double acid etching (DAE). The experimental implants with or without HA nanoparticles were surgically placed in rat femur and an implant push-in test was performed after two weeks of healing. The deposition of HA nanoparticles on the DAE surface increased the mechanical withstanding load by 129% and 782% as compared to the control DAE and turned implants, respectively. Micro-computed tomography-based 3D bone morphometry revealed equivalent bone volumes around the DAE implant with or without HA nanoparticles. These data suggest that the discrete deposition of HA nanoparticles accelerates the early osseointegration process, likely through increased shear bonding strengths.

The effects of Bacillus coagulans-fermented and non-fermented Ginkgo biloba on abdominal fat deposition and meat quality of Peking duck.

Science.gov (United States)

Liu, Xiaoyan; Cao, Guanjun; Zhou, Jinglong; Yao, Xuan; Fang, Binghu

2017-07-01

In order to evaluate the effects of Bacillus coagulans-fermented Ginkgo biloba (FG) and non-fermented G. biloba (NFG) on abdominal fat deposition and meat quality, 270 female Peking ducks were randomly assigned to the following experimental groups: a control group (fed a basal diet), an NFG group (fed a basal diet + 0.3% NFG), and an FG group (fed a basal diet + 0.3% FG). Body weight and feed intake were recorded weekly, and feed conversion ratio was calculated to assess growth performance. After 6 wk, 18 ducks from each group were killed. Abdominal fat ratio and pH (at 45 min and 24 h postmortem), color parameters (lightness, redness, and yellowness), water-holding capacity, cooking loss, shear force, and intramuscular fat and fatty acid contents were measured. Six more ducks were killed to isolate RNA from their abdominal fat tissue for measurements of peroxisome proliferator-activated receptor-γ (PPARγ), obese (leptin), and adiponectin (ADP) expression using real-time polymerase chain reaction. The results revealed that body weight gain was higher in the FG group than in the control and NFG groups, whereas feed conversion ratio was lower (P < 0.05). The abdominal fat contents were lower in the NFG and FG groups than in the control group (P < 0.05). The NFG and FG groups had lower levels of saturated fatty acids (mainly palmitic acid) and higher levels of polyunsaturated fatty acids (mainly linoleic acid and arachidonic acid) than the control group. The mRNA expressions of PPARγ, leptin, and ADP in abdominal fat tissue were significantly increased in the NFG and FG groups, and the mRNA expression of PPARγ was higher in the FG group than in the NFG group (P < 0.05). These results suggest that fermenting G. biloba reduces the deposition of abdominal fat and improves the fatty acid profile of Peking duck meat. © 2017 Poultry Science Association Inc.

Discussion on well field technology for acid in-situ leaching of uranium at a deposit of Yining uranium mine

International Nuclear Information System (INIS)

Ye Shandong; Wu Yunhui; Yin Guifang

2005-01-01

The characteristics of geology and hydrogeology of a uranium deposit, the make-up and use of lixiviant, equilibrium control of push-pull, improvement of air lift efficiency, layout of well net, and management of well construction are described. (authors)

Photo-sensitive Ge nanocrystal based films controlled by substrate deposition temperature

KAUST Repository

Stavarache, Ionel

2017-07-21

Lowering the temperature of crystallization by deposition of thin films on a heated substrate represents the easiest way to find new means to develop and improve new working devices based on nanocrystals embedded in thin films. The improvements are strongly related with the increasing of operation speed, substantially decreasing the energy consumption and reducing unit fabrication costs of the respective semiconductor devices. This approach avoids major problems, such as those related to diffusion or difficulties in controlling of nanocrystallites size, which appear during thermal treatments at high temperatures after deposition. It is reported here the significant progress introduced by synthesis procedure to the in-situ structuring of Ge nanocrystallites in SiO₂ thin films by heating the substrate at low temperature, 400 °C during co-deposition of Ge and SiO₂ by magnetron sputtering. As a proof-of-concept, a Si/Ge-NCs:SiO₂ photo-sensitive structure was fabricated thereof and characterized. The structure shows superior performance on broad operation bandwidth from visible to near-infrared, as strong rectification properties in dark, significant current rise in the inversion mode when illuminated, high responsivity, high photo-detectivity of 10¹⁴ Jones, quick response and significant conversion efficiency of 850 %. This simple preparation approach brings an important contribution to the efort of structuring Ge nanocrystallites in SiO₂ thin films at a lower temperature for the purpose of using these materials for devices in optoelectronics, solar cells and electronics on flexible substrates.

Photo-sensitive Ge nanocrystal based films controlled by substrate deposition temperature

Science.gov (United States)

Stavarache, Ionel; Maraloiu, Valentin Adrian; Negrila, Catalin; Prepelita, Petronela; Gruia, Ion; Iordache, Gheorghe

2017-10-01

Lowering the temperature of crystallization by deposition of thin films on a heated substrate represents the easiest way to find new means to develop and improve new working devices based on nanocrystals embedded in thin films. The improvements are strongly related with the increasing of operation speed, substantially decreasing the energy consumption and reducing unit fabrication costs of the respective semiconductor devices. This approach avoids major problems, such as those related to diffusion or difficulties in controlling nanocrystallites size, which appear during thermal treatments at high temperatures after deposition. This article reports on a significant progress given by structuring Ge nanocrystals (Ge-NCs) embedded in silicon dioxide (SiO2) thin films by heating the substrate at 400 °C during co-deposition of Ge and SiO2 by magnetron sputtering. As a proof-of-concept, a Si/Ge-NCs:SiO2 photo-sensitive structure was fabricated thereof and characterized. The structure shows superior performance on broad operation bandwidth from visible to near-infrared, as strong rectification properties in dark, significant current rise in the inversion mode when illuminated, high responsivity, high photo-detectivity of 1014 Jones, quick response and significant conversion efficiency with peak value reaching 850% at -1 V and about 1000 nm. This simple preparation approach brings an important contribution to the effort of structuring Ge nanocrystallites in SiO2 thin films at a lower temperature for the purpose of using these materials for devices in optoelectronics, solar cells and electronics on flexible substrates.

Dynamic modeling and control of industrial crude terephthalic acid hydropurification process

Energy Technology Data Exchange (ETDEWEB)

Li, Zhi; Zhong, Weimin; Liu, Yang; Luo, Na; Qian, Feng [East China University of Science and Technology, Shanghai (China)

2015-04-15

Purified terephthalic acid (PTA) is critical to the development of the polyester industry. PTA production consists of p-xylene oxidation reaction and crude terephthalic acid (CTA) hydropurification. The hydropurification process is necessary to eliminate 4-carboxybenzaldehyde (4-CBA), which is a harmful byproduct of the oxidation reaction process. Based on the dynamic model of the hydropurification process, two control systems are studied using Aspen Dynamics. The first system is the ratio control system, in which the mass flows of CTA and deionized water are controlled. The second system is the multivariable predictive control-proportional-integral-derivative cascade control strategy, in which the concentrations of 4-CBA and carbon monoxide are chosen as control variables and the reaction temperature and hydrogen flow are selected as manipulated variables. A detailed dynamic behavior is investigated through simulation. Results show that the developed control strategies exhibit good control performances, thereby providing theoretical guidance for advanced control of industry-scale PTA production.

A seasonal nitrogen deposition budget for Rocky Mountain National Park.

Science.gov (United States)

Benedict, K B; Carrico, C M; Kreidenweis, S M; Schichtel, B; Malm, W C; Collett, J L

2013-07-01

Nitrogen deposition is a concern in many protected ecosystems around the world, yet few studies have quantified a complete reactive nitrogen deposition budget including all dry and wet, inorganic and organic compounds. Critical loads that identify the level at which nitrogen deposition negatively affects an ecosystem are often defined using incomplete reactive nitrogen budgets. Frequently only wet deposition of ammonium and nitrate are considered, despite the importance of other nitrogen deposition pathways. Recently, dry deposition pathways including particulate ammonium and nitrate and gas phase nitric acid have been added to nitrogen deposition budgets. However, other nitrogen deposition pathways, including dry deposition of ammonia and wet deposition of organic nitrogen, still are rarely included. In this study, a more complete seasonal nitrogen deposition budget was constructed based on observations during a year-long study period from November 2008 to November 2009 at a location on the east side of Rocky Mountain National Park (RMNP), Colorado, USA. Measurements included wet deposition of ammonium, nitrate, and organic nitrogen, PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 microm, nitrate, and ammonium) concentrations of ammonium, nitrate, and organic nitrogen, and atmospheric gas phase concentrations of ammonia, nitric acid, and NO2. Dry deposition fluxes were determined from measured ambient concentrations and modeled deposition velocities. Total reactive nitrogen deposition by all included pathways was found to be 3.65 kg N x ha(-1) yr(-1). Monthly deposition fluxes ranged from 0.06 to 0.54 kg N x ha(-1)yr(-1), with peak deposition in the month of July and the least deposition in December. Wet deposition of ammonium and nitrate were the two largest deposition pathways, together contributing 1.97 kg N x ha(-1)yr(-1) or 54% of the total nitrogen deposition budget for this region. The next two largest deposition pathways were wet

Influence of phosphorus content of coconut oil on deposit and performance of plant oil pressure stoves

Energy Technology Data Exchange (ETDEWEB)

Kratzeisen, M.; Mueller, J. [Institut fuer Agrartechnik, Universitaet Hohenheim (440e), Garbenstrasse 9, D-70593 Stuttgart (Germany)

2010-11-15

Influence of phosphorus lipids on formation of deposits and performance of plant oil pressure stoves was investigated. Refined coconut oil with an original phosphorous content of 5.9 mg/kg was used as base for fuel blends by adding lecithin to adjust increased phosphorous concentrations of 32.2, 51.6 and 63.0 mg/kg. The fuel blends were analysed for acid value, iodine value, total contamination, ash content and Conradson carbon residue according to standard methods. In burning trials, the specific fuel consumption, the required frequency of nozzle cleaning and the amount of deposits in the vaporizer were measured. Results showed an exponential increase of deposits in the vaporizer when phosphorous content was increased: deposits amounted to 0.12 g/kg of consumed fuel for unblended coconut oil and 0.92 g/kg for the blend with the highest phosphorous content. Furthermore, increased phosphorous content caused higher fuel consumption of 0.375 kg/h compared to 0.316 kg/h for the control. (author)

Acid rain information book. Final report

International Nuclear Information System (INIS)

1983-05-01

Acid rain is one of the most widely publicized environmental issues of the day. The potential consequences of widespread acid rain demand that the phenomenon be carefully evaluated. Review of the literature shows a rapidly growing body of knowledge, but also reveals major gaps in understanding that need to be narrowed. This document discusses aspects of the acid rain phenomenon, points out areas of uncertainty and summarizes current and projected research. The report is organized by a logical progression from sources of pollutants affecting acid rain formation to the atmospheric transport and transformation of those pollutants and finally to the deposition of acid rain, the effects of that deposition, and possible mitigative measures and regulatory options. This information is followed by a discussion of uncertainties in the understanding of the acid rain phenomenon and a description of current and proposed research by responsible government agencies and other concerned organizations

Characterization and temperature controlling property of TiAlN coatings deposited by reactive magnetron co-sputtering

Energy Technology Data Exchange (ETDEWEB)

Chen, J.T. [School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Wang, J. [School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); National Key Laboratory of Surface Engineering, Lanzhou Institute of Physics, Lanzhou 730000 (China); Zhang, F.; Zhang, G.A.; Fan, X.Y.; Wu, Z.G. [School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Yan, P.X. [School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute Chemical and Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)], E-mail: pxyan@lzu.edu.cn

2009-03-20

Titanium aluminum nitride (TiAlN) ternary coating is a potential material which is expected to be applied on satellite for thermal controlling. In order to investigate thermal controlling property, TiAlN coatings were deposited on Si wafers with different N{sub 2} and Ar flux ratio by reactive magnetron co-sputtering. The structure, morphology, chemical composition and optical reflectance are investigated by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), atom force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and spectrophotometer, respectively. The orientation of the coatings depends on the N{sub 2}/Ar flux ratio. The coatings deposited with N{sub 2}/Ar ratio of 10, 30 and 60% show the cubic-TiN [2 2 0] preferred orientation and the coating deposited with N{sub 2}/Ar ratio of 100% exhibits the phase of hexagonal-AlN and cubic-TiN. The surface of the coatings becomes more compact and smoother with the N{sub 2}/Ar ratios increase. XPS spectrum indicates that the oxides (TiO{sub 2} and Al{sub 2}O{sub 3}), oxynitride (TiN{sub x}O{sub y}) and nitrides (TiN and AlN{sub x}) appear at the surface of the coatings. Ignoring internal power, the optimum equilibrium temperature of TiAlN coatings is 18 deg. C and the equilibrium temperature after heat-treated has slight change, which provides the prospective application on thermal controlling.

Characterization of amorphous yttria layers deposited by aqueous solutions of Y-chelate alkoxides complex

Energy Technology Data Exchange (ETDEWEB)

Kim, Young-Soon, E-mail: kyscjb@i-sunam.com; Lee, Yu-Ri; Kim, Byeong-Joo; Lee, Jae-Hun; Moon, Seung-Hyun; Lee, Hunju

2015-01-15

Highlights: • Economical method for crack-free amorphous yttria layer deposition by dip coating. • Simpler process for planar yttria film as a diffusion barrier and nucleation layer. • Easy control over the film properties with better characteristics. • Easy control over the thickness of the deposited films. • A feasible process that can be easily adopted by HTSCC industries. - Abstract: Crack-free amorphous yttria layers were deposited by dip coating in solutions of different Y-chelate alkoxides complex. Three Y-chelate solutions of different concentrations were prepared using yttrium acetate tetrahydrate, yttrium stearic acid as Y source materials. PEG, diethanolamine were used as chelating agents, while ethanol, methanol and tetradecane were used as solvent. Three different combinations of chelating and solvents were used to prepare solutions for Y{sub 2}O{sub 3} dip coating on SUS, electropolished and non-electropolished Hastelloy C-276 substrates. The thickness of the films was varied by changing the number of dipping cycles. At an optimized condition, the substrate surface roughness (rms) value was reduced from ∼50 nm to ∼1 nm over a 10 × 10 μm{sup 2} area. After Y{sub 2}O{sub 3} deposition, MgO was deposited using ion-beam assisted deposition (IBAD), then LaMnO{sub 3} (LMO) was deposited using sputtering and GdBCO was deposited using reactive co-evaporation by deposition and reaction (RCE-DR). Detailed X-ray study indicates that LMO/MgO/Y{sub 2}O{sub 3} and GdBCO/LMO/MgO/Y{sub 2}O{sub 3} stack films have good out-of-plane and in-plane textures with strong c-axis alignment. The critical current (Ic) of GdBCO/LMO/MgO/Y{sub 2}O{sub 3} multilayer structure varied from 190 to 420 A/cm with different solutions, when measured at 77 K. These results demonstrated that amorphous yttria can be easily deposited by dip coating using Y-chelates complex as a diffusion barrier and nucleation layer.

Study of the adhesive properties versus stability/aging of hernia repair meshes after deposition of RF activated plasma polymerized acrylic acid coating

International Nuclear Information System (INIS)

Rivolo, Paola; Nisticò, Roberto; Barone, Fabrizio; Faga, Maria Giulia; Duraccio, Donatella; Martorana, Selanna; Ricciardi, Serena; Magnacca, Giuliana

2016-01-01

In order to confer adhesive properties to commercial polypropylene (PP) meshes, a surface plasma-induced deposition of poly-(acrylic acid) (PPAA) is performed. Once biomaterials were functionalized, different post-deposition treatments (i.e. water washing and/or thermal treatments) were investigated with the aim of monitoring the coating degradation (and therefore the loss of adhesion) after 3 months of aging in both humid/oxidant (air) and inert (nitrogen) atmospheres. A wide physicochemical characterization was carried out in order to evaluate the functionalization effectiveness and the adhesive coating homogeneity by means of static water drop shape analysis and several spectroscopies (namely, FTIR, UV–Visible and X-ray Photoemission Spectroscopy). The modification of the adhesion properties after post-deposition treatments as well as aging under different storage atmospheres were investigated by means of Atomic Force Microscopy (AFM) used in Force/Distance (F/D) mode. This technique confirms itself as a powerful tool for unveiling the surface adhesion capacity as well as the homogeneity of the functional coatings along the fibers. Results obtained evidenced that post-deposition treatments are mandatory in order to remove all oligomers produced during the plasma-treatment, whereas aging tests evidenced that these devices can be simply stored in presence of air for at least three months without a meaningful degradation of the original properties. - Highlights: • Plasma polymerized surface functionalization of hernia-repair meshes was used to confer adhesive properties. • The stability of the adhesive coating was verified under different post-deposition conditions. • The use of AFM in F/D mode was selected to monitor the coating degradation.

Study of the adhesive properties versus stability/aging of hernia repair meshes after deposition of RF activated plasma polymerized acrylic acid coating

Energy Technology Data Exchange (ETDEWEB)

Rivolo, Paola [Politecnico di Torino, Department of Applied Science and Technology, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Nisticò, Roberto, E-mail: roberto.nistico@unito.it [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy); Barone, Fabrizio [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy); Faga, Maria Giulia; Duraccio, Donatella [CNR-IMAMOTER, Strada delle Cacce 73, 10135 Torino (Italy); Martorana, Selanna [Herniamesh S.r.l., Via F.lli Meliga 1/C, 10034 Chivasso (Italy); Ricciardi, Serena [Politecnico di Torino, Department of Applied Science and Technology, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Magnacca, Giuliana [University of Torino, Department of Chemistry and NIS Centre, Via P. Giuria 7, 10125 Torino (Italy)

2016-08-01

In order to confer adhesive properties to commercial polypropylene (PP) meshes, a surface plasma-induced deposition of poly-(acrylic acid) (PPAA) is performed. Once biomaterials were functionalized, different post-deposition treatments (i.e. water washing and/or thermal treatments) were investigated with the aim of monitoring the coating degradation (and therefore the loss of adhesion) after 3 months of aging in both humid/oxidant (air) and inert (nitrogen) atmospheres. A wide physicochemical characterization was carried out in order to evaluate the functionalization effectiveness and the adhesive coating homogeneity by means of static water drop shape analysis and several spectroscopies (namely, FTIR, UV–Visible and X-ray Photoemission Spectroscopy). The modification of the adhesion properties after post-deposition treatments as well as aging under different storage atmospheres were investigated by means of Atomic Force Microscopy (AFM) used in Force/Distance (F/D) mode. This technique confirms itself as a powerful tool for unveiling the surface adhesion capacity as well as the homogeneity of the functional coatings along the fibers. Results obtained evidenced that post-deposition treatments are mandatory in order to remove all oligomers produced during the plasma-treatment, whereas aging tests evidenced that these devices can be simply stored in presence of air for at least three months without a meaningful degradation of the original properties. - Highlights: • Plasma polymerized surface functionalization of hernia-repair meshes was used to confer adhesive properties. • The stability of the adhesive coating was verified under different post-deposition conditions. • The use of AFM in F/D mode was selected to monitor the coating degradation.

Integrated gasification combined cycle for acid rain control

Energy Technology Data Exchange (ETDEWEB)

Simbeck, D.R.; Dickenson, R.L.

1986-10-01

The role of integrated coal gasification combined-cycle power plants in the abatement of emission of SO/sub 2/ and NO/sub 2/ which lead to acid rain is discussed. The economics of this IGCC approach are assessed for a nominal 500 MW plant size. Phased construction of IGCC plants is recommended as a means of reducing SO/sub 2/ and NO/sub x/ emissions noting that high-sulfur coals could continue to be used. It is also noted that phased construction IGCC is the only acid rain control technology that greatly reduces NO/sub x/. 17 references.

Fouling deposition characteristic by variation of coal particle size and deposition temperature in DTF (Drop Tube Furnace)

Energy Technology Data Exchange (ETDEWEB)

Namkung, Hueon; Jeon, Youngshin; Kim, Hyungtaek [Ajou Univ., Suwon (Korea, Republic of). Div. of Energy Systems Research; Xu, Li-hua [IAE, Suwon (Korea, Republic of). Plant Engineering Center

2013-07-01

One of the major operation obstacles in gasification process is ash deposition phenomenon. In this investigation, experiment was carried out to examine coal fouling characteristics using a laminar DTF (Drop Tube Furnace) with variation of operating condition such as different coal size, and probe surface temperature. Four different samples of pulverized coal were injected into DTF under various conditions. The ash particles are deposited on probe by impacting and agglomerating action. Fouling grains are made of eutectic compound, which is made by reacting with acid minerals and alkali minerals, in EPMA (Electron Probe Micro-Analysis). And agglomeration area of fouling at top layer is wide more than it of middle and bottom layer. The major mineral factors of fouling phenomenon are Fe, Ca, and Mg. The deposition quantity of fouling increases with increasing particle size, high alkali mineral (Fe, Ca, and Mg) contents, and ash deposition temperature.

The Neogene molasse deposits of the Zagros Mountains in central Dezful Embayment: facies, sedimentary environments and controls

Directory of Open Access Journals (Sweden)

Ali Hossein Jalilian

2016-03-01

Full Text Available The upper part of Neogene sequence of the Zagros Mountains consists of a clastic succession which is identified as Aghajari and Bakhtyari formations. The sequence is an excellent example of synorogenic sedimentation or molasse deposited in northern portion of the Zagros foreland basin. Sedimentological analysis of an outcrop section representing Miocene-Pliocene sediments in central Dezful Embayment resulted in recognizing 9 lithofacies and 4 architectural elements. These lithofacies include conglometate (Gt, Gh, Gmm, sandstone (Sp, Sh, Sr, St and mudstone (Fm, Fl that were deposited in meandering stream, braided river and alluvial fan environments. Paleocurrent analysis of cross-beds, channels and asymmetric ripple marks indicate that these Neogene clastics were mainly drived from Cretaceous to Paleogene highlands in the Zagros Mountains on the north. This stratigraphic record is coarsening-upward and formed by a regressive depositional megacycle under arid climate. Facies and depositional history analysis show that sedimentation of the Zagros molasse was primarily controlled by base-level changes rather than catchment lithology or climate. The sedimentary record of this regressive megacycle reveales the base-level was constantly falling down on one hand and the provenance was uplifting on the other hand. Tectonic activities and Zagros Mountains rising in the Late Miocene resulted in deposition of fining-upward point-bar and floodplain sequences of the Aghajari Formation in low-gradient meandering streams. The Lahbari Member of the Aghajari Formation represents deposition in braided rivers that composed predominantly of flood-plain deposits in the Early Pliocene. Finally, the sedimentary cycle of the Zagros molasse deposits terminated with massive conglomerates of the Bakhtyari Formation deposited in large alluvial fans near the source area.

Controlled surface diffusion in plasma-enhanced chemical vapor deposition of GaN nanowires

International Nuclear Information System (INIS)

Hou, W C; Hong, Franklin Chau-Nan

2009-01-01

This study investigates the growth of GaN nanowires by controlling the surface diffusion of Ga species on sapphire in a plasma-enhanced chemical vapor deposition (CVD) system. Under nitrogen-rich growth conditions, Ga has a tendency to adsorb on the substrate surface diffusing to nanowires to contribute to their growth. The significance of surface diffusion on the growth of nanowires is dependent on the environment of the nanowire on the substrate surface as well as the gas phase species and compositions. Under nitrogen-rich growth conditions, the growth rate is strongly dependent on the surface diffusion of gallium, but the addition of 5% hydrogen in nitrogen plasma instantly diminishes the surface diffusion effect. Gallium desorbs easily from the surface by reaction with hydrogen. On the other hand, under gallium-rich growth conditions, nanowire growth is shown to be dominated by the gas phase deposition, with negligible contribution from surface diffusion. This is the first study reporting the inhibition of surface diffusion effects by hydrogen addition, which can be useful in tailoring the growth and characteristics of nanowires. Without any evidence of direct deposition on the nanowire surface, gallium and nitrogen are shown to dissolve into the catalyst for growing the nanowires at 900 deg. C.

Laboratory Deposition Apparatus to Study the Effects of Wax Deposition on Pipe Magnetic Field Leakage Signals

Directory of Open Access Journals (Sweden)

Karim Mohd Fauzi Abd

2014-07-01

Full Text Available Accurate technique for wax deposition detection and severity measurement on cold pipe wall is important for pipeline cleaning program. Usually these techniques are validated by conventional techniques on laboratory scale wax deposition flow loop. However conventional techniques inherent limitations and it is difficult to reproduce a predetermine wax deposit profile and hardness at designated location in flow loop. An alternative wax deposition system which integrates modified pour casting method and cold finger method is presented. This system is suitable to reproduce high volume of medium hard wax deposit in pipe with better control of wax deposit profile and hardness.

Morphology control in thin films of PS:PLA homopolymer blends by dip-coating deposition

Energy Technology Data Exchange (ETDEWEB)

Vital, Alexane [Interfaces, Confinement, Matériaux et Nanostructures (ICMN), CNRS-Université d’Orléans, UMR 7374, 1B Rue de la Férollerie, C.S. 40059, 45071 Orléans Cedex 2 (France); Groupe de recherches sur l’énergétique des milieux ionisés (GREMI), CNRS-Université d’Orléans, UMR 7344, 14 rue d' Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France); Vayer, Marylène [Interfaces, Confinement, Matériaux et Nanostructures (ICMN), CNRS-Université d’Orléans, UMR 7374, 1B Rue de la Férollerie, C.S. 40059, 45071 Orléans Cedex 2 (France); Tillocher, Thomas; Dussart, Rémi [Groupe de recherches sur l’énergétique des milieux ionisés (GREMI), CNRS-Université d’Orléans, UMR 7344, 14 rue d' Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France); Boufnichel, Mohamed [STMicroelectronics, 16, rue Pierre et Marie Curie, B.P. 7155, 37071 Tours Cedex 2 (France); and others

2017-01-30

Highlights: • A process to control the morphology of polymer blends thin film is described. • It is based on the use of dip-coating at various withdrawal speeds. • The process is examined within the capillary and the draining regimes. • The final dried morphology is controlled by the regime of deposition. • This study is of high interest for the preparation of advanced functional surfaces. - Abstract: In this work, smooth polymer films of PS, PLA and their blends, with thicknesses ranging from 20 nm up to 400 nm and very few defects on the surface were obtained by dip-coating. In contrast to the process of spin-coating which is conventionally used to prepare thin films of polymer blends, we showed that depending on the deposition parameters (withdrawal speed and geometry of the reservoir), various morphologies such as layered films and laterally phase-separated domains could be formed for a given blend/solvent pair, offering much more opportunities compared to the spin-coating process. This diversity of morphologies was explained by considering the superposition of different phenomena such as phase separation process, dewetting and vitrification in which parameters such as the drying time, the compatibility of the polymer/solvent pairs and the affinity of the polymer towards the interfaces were suspected to play a significant role. For that purpose, the process of dip-coating was examined within the capillary and the draining regimes (for low and high withdrawal speed respectively) in order to get a full description of the thickness variation and evaporation rate as a function of the deposition parameters.

MAPLE deposition of nanomaterials

International Nuclear Information System (INIS)

Caricato, A.P.; Arima, V.; Catalano, M.; Cesaria, M.; Cozzoli, P.D.; Martino, M.; Taurino, A.; Rella, R.; Scarfiello, R.; Tunno, T.; Zacheo, A.

2014-01-01

The matrix-assisted pulsed laser evaporation (MAPLE) has been recently exploited for depositing films of nanomaterials by combining the advantages of colloidal inorganic nanoparticles and laser-based techniques. MAPLE-deposition of nanomaterials meeting applicative purposes demands their peculiar properties to be taken into account while planning depositions to guarantee a congruent transfer (in terms of crystal structure and geometric features) and explain the deposition outcome. In particular, since nanofluids can enhance thermal conductivity with respect to conventional fluids, laser-induced heating can induce different ablation thermal regimes as compared to the MAPLE-treatment of soft materials. Moreover, nanoparticles exhibit lower melting temperatures and can experience pre-melting phenomena as compared to their bulk counterparts, which could easily induce shape and or crystal phase modification of the material to be deposited even at very low fluences. In this complex scenario, this review paper focuses on examples of MAPLE-depositions of size and shape controlled nanoparticles for different applications highlights advantages and challenges of the MAPLE-technique. The influence of the deposition parameters on the physical mechanisms which govern the deposition process is discussed.

MAPLE deposition of nanomaterials

Energy Technology Data Exchange (ETDEWEB)

Caricato, A.P., E-mail: annapaola.caricato@le.infn.it [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Arima, V.; Catalano, M. [National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Cesaria, M. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Cozzoli, P.D. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Martino, M. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Taurino, A.; Rella, R. [Institute for Microelectronics and Microsystems, IMM-CNR, Via Monteroni, I-73100 Lecce (Italy); Scarfiello, R. [National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy); Tunno, T. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); Zacheo, A. [Department of Mathematics and Physics “E. De Giorgi”, University of Salento, Via Arnesano, I-73100 Lecce (Italy); National Nanotechnology Laboratory (NNL), CNR Istituto Nanoscienze, c/o Distretto Tecnologico, Via Arnesano n. 16, I-73100 Lecce (Italy)

2014-05-01

The matrix-assisted pulsed laser evaporation (MAPLE) has been recently exploited for depositing films of nanomaterials by combining the advantages of colloidal inorganic nanoparticles and laser-based techniques. MAPLE-deposition of nanomaterials meeting applicative purposes demands their peculiar properties to be taken into account while planning depositions to guarantee a congruent transfer (in terms of crystal structure and geometric features) and explain the deposition outcome. In particular, since nanofluids can enhance thermal conductivity with respect to conventional fluids, laser-induced heating can induce different ablation thermal regimes as compared to the MAPLE-treatment of soft materials. Moreover, nanoparticles exhibit lower melting temperatures and can experience pre-melting phenomena as compared to their bulk counterparts, which could easily induce shape and or crystal phase modification of the material to be deposited even at very low fluences. In this complex scenario, this review paper focuses on examples of MAPLE-depositions of size and shape controlled nanoparticles for different applications highlights advantages and challenges of the MAPLE-technique. The influence of the deposition parameters on the physical mechanisms which govern the deposition process is discussed.

Deposition kinetics of quantum dots and polystyrene latex nanoparticles onto alumina: role of water chemistry and particle coating.

Science.gov (United States)

Quevedo, Ivan R; Olsson, Adam L J; Tufenkji, Nathalie

2013-03-05

A clear understanding of the factors controlling the deposition behavior of engineered nanoparticles (ENPs), such as quantum dots (QDs), is necessary for predicting their transport and fate in natural subsurface environments and in water filtration processes. A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the effect of particle surface coatings and water chemistry on the deposition of commercial QDs onto Al2O3. Two carboxylated QDs (CdSe and CdTe) with different surface coatings were compared with two model nanoparticles: sulfate-functionalized (sPL) and carboxyl-modified (cPL) polystyrene latex. Deposition rates were assessed over a range of ionic strengths (IS) in simple electrolyte (KCl) and in electrolyte supplemented with two organic molecules found in natural waters; namely, humic acid and rhamnolipid. The Al2O3 collector used here is selected to be representative of oxide patches found on the surface of aquifer or filter grains. Deposition studies showed that ENP deposition rates on bare Al2O3 generally decreased with increasing salt concentration, with the exception of the polyacrylic-acid (PAA) coated CdTe QD which exhibited unique deposition behavior due to changes in the conformation of the PAA coating. QD deposition rates on bare Al2O3 were approximately 1 order of magnitude lower than those of the polystyrene latex nanoparticles, likely as a result of steric stabilization imparted by the QD surface coatings. Adsorption of humic acid or rhamnolipid on the Al2O3 surface resulted in charge reversal of the collector and subsequent reduction in the deposition rates of all ENPs. Moreover, the ratio of the two QCM-D output parameters, frequency and dissipation, revealed key structural information of the ENP-collector interface; namely, on bare Al2O3, the latex particles were rigidly attached as compared to the more loosely attached QDs. This study emphasizes the importance of considering the nature of ENP coatings as well

Climax-Type Porphyry Molybdenum Deposits

Science.gov (United States)

Ludington, Steve; Plumlee, Geoffrey S.

2009-01-01

Climax-type porphyry molybdenum deposits, as defined here, are extremely rare; thirteen deposits are known, all in western North America and ranging in age from Late Cretaceous to mainly Tertiary. They are consistently found in a postsubduction, extensional tectonic setting and are invariably associated with A-type granites that formed after peak activity of a magmatic cycle. The deposits consist of ore shells of quartz-molybdenite stockwork veins that lie above and surrounding the apices of cupola-like, highly evolved, calc-alkaline granite and subvolcanic rhyolite-porphyry bodies. These plutons are invariably enriched in fluorine (commonly >1 percent), rubidium (commonly >500 parts per million), and niobium-tantalum (Nb commonly >50 parts per million). The deposits are relatively high grade (typically 0.1-0.3 percent Mo) and may be very large (typically 100-1,000 million tons). Molybdenum, as MoS2, is the primary commodity in all known deposits. The effect on surface-water quality owing to natural influx of water or sediment from a Climax-type mineralized area can extend many kilometers downstream from the mineralized area. Waste piles composed of quartz-silica-pyrite altered rocks will likely produce acidic drainage waters. The potential exists for concentrations of fluorine or rare metals in surface water and groundwater to exceed recommended limits for human consumption near both mined and unmined Climax-type deposits.

Uniform deposition of uranium hexafluoride (UF6): Standardized mass deposits and controlled isotopic ratios using a thermal fluorination method

Energy Technology Data Exchange (ETDEWEB)

McNamara, Bruce K.; O’Hara, Matthew J.; Casella, Andrew M.; Carter, Jennifer C.; Addleman, R. Shane; MacFarlan, Paul J.

2016-07-01

Abstract: We report a convenient method for the generation of volatile uranium hexafluoride (UF6) from solid uranium oxides and other uranium compounds, followed by uniform deposition of low levels of UF6 onto sampling coupons. Under laminar flow conditions, UF6 is shown to interact with surfaces within the chamber to a highly predictable degree. We demonstrate the preparation of uranium deposits that range between ~0.01 and 470±34 ng∙cm-2. The data suggest the method can be extended to creating depositions at the sub-picogram∙cm-2 level. Additionally, the isotopic composition of the deposits can be customized by selection of the uranium source materials. We demonstrate a layering technique whereby two uranium solids, each with a different isotopic composition, are employed to form successive layers of UF6 on a surface. The result is an ultra-thin deposit of UF6 that bears an isotopic signature that is a composite of the two uranium sources. The reported deposition method has direct application to the development of unique analytical standards for nuclear safeguards and forensics.

Association of Serum Uric Acid with Preeclampsia: A Case Control Study

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Razia Sultana

2013-07-01

Full Text Available Background: Preeclampsia (PE is still one of the important causes of maternal and fetal mortality in Bangladesh. Many researches have been done to identify a unique screening test that would predict the risk of developing PE before the classic symptoms appear. One of the most accessible and easiest screening tests is serum uric acid measurement. Numerous studies have demonstrated a relation between elevated maternal serum uric acid levels and adverse maternal and fetal outcome. Among several pathophysiologic factors the most commonly accepted explanation for hyperuricemia in PE is increased reabsorption and decreased excretion of uric acid.Objective: The aim of the present study was to assess the association of serum uric acid with preeclampsia.Materials and method: A case control study was conducted in the department of Biochemistry, Dhaka Medical College, Dhaka from July 2010 to June 2011. A total number of 100 pregnant women in third trimester of pregnancy attending in Obstetrics and Gynaecology department of Dhaka Medical College Hospital were selected purposively as study subjects. Among them 50 pregnant women with preeclampsia were selected as cases and 50 normal healthy pregnant women as controls.Results: Most of the study subjects were within 21 – 30 years of age group and mean age in case and control was 24.06±3.71 and 24.66±3.22 years respectively, which was not statistically different. Mean gestational age in case and control was 33.50±2.55 weeks and 33.60±2.95 weeks respectively, which was also not statistically different. Among the study subjects majority was primi in both groups (case 76%, contol 58% showing no statistical significance. Majority of the subjects in both groups were irregular in their antenatal checkup (case 52%, contol 40%. Uric acid concentration was measured in all the study subjects. The mean serum uric acid concentration in cases and controls were 7.01±1.90 mg/dl and 4.55±1.63 mg/dl respectively. This