Bottom-up nutrient and top-down fish impacts on insect-mediated mercury flux from aquatic ecosystems.

Science.gov (United States)

Jones, Taylor A; Chumchal, Matthew M; Drenner, Ray W; Timmins, Gabrielle N; Nowlin, Weston H

2013-03-01

Methyl mercury (MeHg) is one of the most hazardous contaminants in the environment, adversely affecting the health of wildlife and humans. Recent studies have demonstrated that aquatic insects biotransport MeHg and other contaminants to terrestrial consumers, but the factors that regulate the flux of MeHg out of aquatic ecosystems via emergent insects have not been studied. The authors used experimental mesocosms to test the hypothesis that insect emergence and the associated flux of MeHg from aquatic to terrestrial ecosystems is affected by both bottom-up nutrient effects and top-down fish consumer effects. In the present study, nutrient addition led to an increase in MeHg flux primarily by enhancing the biomass of emerging insects whose tissues were contaminated with MeHg, whereas fish decreased MeHg flux primarily by reducing the biomass of emerging insects. Furthermore, the authors found that these factors are interdependent such that the effects of nutrients are more pronounced when fish are absent, and the effects of fish are more pronounced when nutrient concentrations are high. The present study is the first to demonstrate that the flux of MeHg from aquatic to terrestrial ecosystems is strongly enhanced by bottom-up nutrient effects and diminished by top-down consumer effects. Copyright © 2012 SETAC.

Primary water chemistry monitoring from the point of view of radiation build-up

International Nuclear Information System (INIS)

Horvath, G.L.; Civin, V.; Pinter, T.

1997-01-01

Basic operational principles of a computer code system calculating the primary circuit corrosion product activities based on actual measured plant chemistry data are presented. The code system consists of two parts: FeSolub.prg: calculates the characteristic iron solubilities based on actual primary water chemistry (H 3 BO 3 KOH, ... etc.) and plant load (MW) data. A developed solubility calculation method has been applied fitted to magnetite solubility data of several authors; RADTRAN.exe: calculates primary circuit water and surface corrosion product activities based on results of FeSolub.prg or planned water chemistry data up to the next shutdown. The computer code system is going to be integrated into a general primary water chemistry monitoring and surveillance system. (author). 15 refs, 4 figs, 3 tabs

Physical organic chemistry in the making

NARCIS (Netherlands)

Engberts, J.B.F.N.

The discipline of physical organic chemistry will continue to occupy a central position in chemistry. The rapid increase in instrumentation and important theoretical developments allow the investigation of many problems of great complexity and challenge. In the next century the leading theme will

Occupational UVR skin protection by make-up

International Nuclear Information System (INIS)

Bonner, R.; Khazova, M.; O'Hagan, J. B.; Squire, H.

2012-01-01

New legislation has been introduced in the Member States of the European Union, covering worker exposure to artificial optical radiation. Use of make-up could reduce the ultraviolet hazard level and provide additional protection for skin against UV radiation (UVR). This is particularly important in entertainment and filming where intentional exposure of the actors and presenters to the very intense light sources may be required for extended periods of time. This document presents the assessment of UVR protection of make-up used in entertainment and demonstrates that the protection level varies considerably for different luminaires and application techniques. An important practical implication of this finding is that make-up alone cannot be considered as a reliable protection measure against skin exposure to actinic UV. (authors)

Occupational UVR skin protection by make-up.

Science.gov (United States)

Bonner, R; Khazova, M; O'Hagan, J B; Squire, H

2012-03-01

New legislation has been introduced in the Member States of the European Union, covering worker exposure to artificial optical radiation. Use of make-up could reduce the ultraviolet hazard level and provide additional protection for skin against UV radiation (UVR). This is particularly important in entertainment and filming where intentional exposure of the actors and presenters to the very intense light sources may be required for extended periods of time. This document presents the assessment of UVR protection of make-up used in entertainment and demonstrates that the protection level varies considerably for different luminaires and application techniques. An important practical implication of this finding is that make-up alone cannot be considered as a reliable protection measure against skin exposure to actinic UV.

Primary water chemistry monitoring from the point of view of radiation build-up

Energy Technology Data Exchange (ETDEWEB)

Horvath, G L [Institute for Electrical Power Research, Budapest (Hungary); Civin, V [Hungarian Electricity Generating Board, Budapest (Hungary); Pinter, T [Nuclear Power Plant PAKS, Budapest (Hungary)

1997-02-01

Basic operational principles of a computer code system calculating the primary circuit corrosion product activities based on actual measured plant chemistry data are presented. The code system consists of two parts: FeSolub.prg: calculates the characteristic iron solubilities based on actual primary water chemistry (H{sub 3}BO{sub 3}KOH, ... etc.) and plant load (MW) data. A developed solubility calculation method has been applied fitted to magnetite solubility data of several authors; RADTRAN.exe: calculates primary circuit water and surface corrosion product activities based on results of FeSolub.prg or planned water chemistry data up to the next shutdown. The computer code system is going to be integrated into a general primary water chemistry monitoring and surveillance system. (author). 15 refs, 4 figs, 3 tabs.

Trophic cascades of bottom-up and top-down forcing on nutrients and plankton in the Kattegat, evaluated by modelling

DEFF Research Database (Denmark)

Petersen, Marcell Elo; Maar, Marie; Larsen, Janus

2017-01-01

The aim of the study was to investigate the relative importance of bottom-up and top-down forcing on trophic cascades in the pelagic food-web and the implications for water quality indicators (summer phytoplankton biomass and winter nutrients) in relation to management. The 3D ecological model....... On annual basis, the system was more bottom-up than top-down controlled. Microzooplankton was found to play an important role in the pelagic food web as mediator of nutrient and energy fluxes. This study demonstrated that the best scenario for improved water quality was a combined reduction in nutrient...

WHAT MAKES CHEMISTRY DIFFICULT?

African Journals Online (AJOL)

IICBA01

School of Natural and Computational Science Dire Dawa University, Ethiopia,. 2 ... lack of teaching aids and the difficulty of the language of chemistry. ... lab every other week consisting of concept pretests on the web, hand-written homework, ...

Brooding fathers, not siblings, take up nutrients from embryos

Science.gov (United States)

Sagebakken, Gry; Ahnesjö, Ingrid; Mobley, Kenyon B.; Gonçalves, Inês Braga; Kvarnemo, Charlotta

2010-01-01

It is well known that many animals with placenta-like structures provide their embryos with nutrients and oxygen. However, we demonstrate here that nutrients can pass the other way, from embryos to the parent. The study was done on a pipefish, Syngnathus typhle, in which males brood fertilized eggs in a brood pouch for several weeks. Earlier research has found a reduction of embryo numbers during the brooding period, but the fate of the nutrients from these ‘reduced’ embryos has been unknown. In this study, we considered whether (i) the brooding male absorbs the nutrients, (ii) siblings absorb them, or (iii) a combination of both. Males were mated to two sets of females, one of which had radioactively labelled eggs (using 14C-labelled amino acids), such that approximately half the eggs in the brood pouch were labelled. This allowed us to trace nutrient uptake from these embryos. We detected that 14C-labelled amino acids were transferred to the male brood pouch, liver and muscle tissue. However, we did not detect any significant 14C-labelled amino-acid absorption by the non-labelled half-siblings in the brood pouch. Thus, we show, to our knowledge, for the first time, that males absorb nutrients derived from embryos through their paternal brood pouch. PMID:19939847

The EPIC nutrient database project (ENDB): a first attempt to standardize nutrient databases across the 10 European countries participating in the EPIC study

DEFF Research Database (Denmark)

Slimani, N.; Deharveng, G.; Unwin, I.

2007-01-01

because there is currently no European reference NDB available. Design: A large network involving national compilers, nutritionists and experts on food chemistry and computer science was set up for the 'EPIC Nutrient DataBase' ( ENDB) project. A total of 550-1500 foods derived from about 37 000...... standardized EPIC 24-h dietary recalls (24-HDRS) were matched as closely as possible to foods available in the 10 national NDBs. The resulting national data sets ( NDS) were then successively documented, standardized and evaluated according to common guidelines and using a DataBase Management System...

Effects of wood chip ash fertilization on soil chemistry in a Norway spruce plantation on a nutrient-poor soil

DEFF Research Database (Denmark)

Ingerslev, Morten; Hansen, Mette; Pedersen, Lars Bo

2014-01-01

of wood chip ash application on soil chemistry in a 44-year-old Norway spruce (Picea abies) plantation on a nutrient-poor soil in Denmark and to investigate the effect of applying different ash types and doses. Soil samples were collected and analyzed 2.5years (3 growing seasons) after ash application....... This study shows that, regardless of ash formulation, preparation or dose, application of wood ash to forest soil has a liming effect in the O-horizon manifested as an increase in CECe, BS and pH. This effect was not seen in the mineral soil within the time frame of this study. At the same time, an increase...... in Cd was found in the O-horizon, corresponding to the amount added in the ashes. Generally, no other increase in soil contents of the heavy metals was seen. Hardening of the wood ash did not decrease the chemical impact on the soil chemistry as compared to non-treated ash whereas an increase in ash...

Two tales of legacy effects on stream nutrient behaviour

Science.gov (United States)

Bieroza, M.; Heathwaite, A. L.

2017-12-01

Intensive agriculture has led to large-scale land use conversion, shortening of flow pathways and increased loads of nutrients in streams. This legacy results in gradual build-up of nutrients in agricultural catchments: in soil for phosphorus (biogeochemical legacy) and in the unsaturated zone for nitrate (hydrologic legacy), controlling the water quality in the long-term. Here we investigate these effects on phosphorus and nitrate stream concentrations using high-frequency (10-5 - 100 Hz) sampling with in situ wet-chemistry analysers and optical sensors. Based on our 5 year study, we observe that storm flow responses differ for both nutrients: phosphorus shows rapid increases (up to 3 orders of magnitude) in concentrations with stream flow, whereas nitrate shows both dilution and concentration effects with increasing flow. However, the range of nitrate concentrations change is narrow (up to 2 times the mean) and reflects chemostatic behaviour. We link these nutrient responses with their dominant sources and flow pathways in the catchment. Nitrate from agriculture (with the peak loading in 1983) is stored in the unsaturated zone of the Penrith Sandstone, which can reach up to 70 m depth. Thus nitrate legacy is related to a hydrologic time lag with long travel times in the unsaturated zone. Phosphorus is mainly sorbed to soil particles, therefore it is mobilised rapidly during rainfall events (biogeochemical legacy). The phosphorus stream response will however depend on how well connected is the stream to the catchment sources (driven by soil moisture distribution) and biogeochemical activity (driven by temperature), leading to both chemostatic and non-chemostatic responses, alternating on a storm-to-storm and seasonal basis. Our results also show that transient within-channel storage is playing an important role in delivery of phosphorus, providing an additional time lag component. These results show, that consistent agricultural legacy in the catchment (high

Liquid phase oxidation chemistry in continuous-flow microreactors.

Science.gov (United States)

Gemoets, Hannes P L; Su, Yuanhai; Shang, Minjing; Hessel, Volker; Luque, Rafael; Noël, Timothy

2016-01-07

Continuous-flow liquid phase oxidation chemistry in microreactors receives a lot of attention as the reactor provides enhanced heat and mass transfer characteristics, safe use of hazardous oxidants, high interfacial areas, and scale-up potential. In this review, an up-to-date overview of both technological and chemical aspects of liquid phase oxidation chemistry in continuous-flow microreactors is given. A description of mass and heat transfer phenomena is provided and fundamental principles are deduced which can be used to make a judicious choice for a suitable reactor. In addition, the safety aspects of continuous-flow technology are discussed. Next, oxidation chemistry in flow is discussed, including the use of oxygen, hydrogen peroxide, ozone and other oxidants in flow. Finally, the scale-up potential for continuous-flow reactors is described.

VVER operational experience - effect of preconditioning and primary water chemistry on radioactivity build-up

International Nuclear Information System (INIS)

Zmitko, M.; Kysela, J.; Dudjakova, K.; Martykan, M.; Janesik, J.; Hanus, V.; Marcinsky, P.

2004-01-01

The primary coolant technology approaches currently used in VVER units are reviewed and compared with those used in PWR units. Standard and modified water chemistries differing in boron-potassium control are discussed. Preparation of the VVER Primary Water Chemistry Guidelines in the Czech Republic is noted. Operational experience of some VVER units, operated in the Czech Republic and Slovakia, in the field of the primary water chemistry, and radioactivity transport and build-up are presented. In Mochovce and Temelin units, a surface preconditioning (passivation) procedure has been applied during hot functional tests. The main principles of the controlled primary water chemistry applied during the hot functional tests are reviewed and importance of the water chemistry, technological and other relevant parameters is stressed regarding to the quality of the passive layer formed on the primary system surfaces. The first operational experience obtained in the course of beginning of these units operation is presented mainly with respect to the corrosion products coolant and surface activities. Effect of the initial passivation performed during hot functional tests and the primary water chemistry on corrosion products radioactivity level and radiation situation is discussed. (author)

make up.contents pg

African Journals Online (AJOL)

spamer

regimes, is a characteristic mineral of water masses of southern origin. During glacial ..... Recent ocean, are adapted to oxygen-rich and nutrient- poor water .... PRELL, W. L. and J. E. KUTZBACH 1987 — Monsoon variability over the past ...

Chemistry of the sea-surface microlayer. 3. Studies on the nutrient chemistry of the northern Arabian Sea

Digital Repository Service at National Institute of Oceanography (India)

Singbal, S.Y.S.; Narvekar, P.V.; Nagarajan, R.

Nutrients showed enrichment in the surface microlayer compared to those in sub-surface water and there was a decreasing trend in the enrichment factor from nearshore to offshore in Northern Arabian Sea. The nutrient concentrations were correlated...

Hydroponics: A Versatile System to Study Nutrient Allocation and Plant Responses to Nutrient Availability and Exposure to Toxic Elements.

Science.gov (United States)

Nguyen, Nga T; McInturf, Samuel A; Mendoza-Cózatl, David G

2016-07-13

Hydroponic systems have been utilized as one of the standard methods for plant biology research and are also used in commercial production for several crops, including lettuce and tomato. Within the plant research community, numerous hydroponic systems have been designed to study plant responses to biotic and abiotic stresses. Here we present a hydroponic protocol that can be easily implemented in laboratories interested in pursuing studies on plant mineral nutrition. This protocol describes the hydroponic system set up in detail and the preparation of plant material for successful experiments. Most of the materials described in this protocol can be found outside scientific supply companies, making the set up for hydroponic experiments less expensive and convenient. The use of a hydroponic growth system is most advantageous in situations where the nutrient media need to be well controlled and when intact roots need to be harvested for downstream applications. We also demonstrate how nutrient concentrations can be modified to induce plant responses to both essential nutrients and toxic non-essential elements.

WERF Nutrient Challenge investigates limits of nutrient removal technologies.

Science.gov (United States)

Neethling, J B; Clark, D; Pramanik, A; Stensel, H D; Sandino, J; Tsuchihashi, R

2010-01-01

The WERF Nutrient Challenge is a multi-year collaborative research initiative established in 2007 to develop and provide current information about wastewater treatment nutrients (specifically nitrogen and phosphorus in wastewater), their characteristics, and bioavailability in aquatic environments to help regulators make informed decisions. The Nutrient Challenge will also provide data on nutrient removal so that treatment facilities can select sustainable, cost-effective methods and technologies to meet permit limits. To meet these goals, the Nutrient Challenge has teamed with a wide array of utilities, agencies, consultants, universities and other researchers and practitioners to collaborate on projects that advance these goals. The Nutrient Challenge is focusing on a different approach to collaborating and leveraging resources (financial and intellectual) on research projects by targeting existing projects and research that correspond with its goals and funding those aspects that the Nutrient Challenge identified as a priority. Because the Nutrient Challenge is focused on collaboration, outreach is an absolutely necessary component of its effectiveness. Through workshops, webinars, a web portal and online compendium, published papers, and conference lectures, the Nutrient Challenge is both presenting important new information, and soliciting new partnerships.

Nutrient depletion from rhizosphere solution by maize grown in soil with long-term compost amendment

Science.gov (United States)

Improved understanding of rhizosphere chemistry will enhance our ability to model nutrient dynamics and on a broader scale, to develop effective management strategies for applied plant nutrients. With a controlled-climate study, we evaluated in situ changes in macro-nutrient concentrations in the rh...

Interactions between temperature and nutrients across levels of ecological organization.

Science.gov (United States)

Cross, Wyatt F; Hood, James M; Benstead, Jonathan P; Huryn, Alexander D; Nelson, Daniel

2015-03-01

Temperature and nutrient availability play key roles in controlling the pathways and rates at which energy and materials move through ecosystems. These factors have also changed dramatically on Earth over the past century as human activities have intensified. Although significant effort has been devoted to understanding the role of temperature and nutrients in isolation, less is known about how these two factors interact to influence ecological processes. Recent advances in ecological stoichiometry and metabolic ecology provide a useful framework for making progress in this area, but conceptual synthesis and review are needed to help catalyze additional research. Here, we examine known and potential interactions between temperature and nutrients from a variety of physiological, community, and ecosystem perspectives. We first review patterns at the level of the individual, focusing on four traits--growth, respiration, body size, and elemental content--that should theoretically govern how temperature and nutrients interact to influence higher levels of biological organization. We next explore the interactive effects of temperature and nutrients on populations, communities, and food webs by synthesizing information related to community size spectra, biomass distributions, and elemental composition. We use metabolic theory to make predictions about how population-level secondary production should respond to interactions between temperature and resource supply, setting up qualitative predictions about the flows of energy and materials through metazoan food webs. Last, we examine how temperature-nutrient interactions influence processes at the whole-ecosystem level, focusing on apparent vs. intrinsic activation energies of ecosystem processes, how to represent temperature-nutrient interactions in ecosystem models, and patterns with respect to nutrient uptake and organic matter decomposition. We conclude that a better understanding of interactions between temperature and

Sign me up! Determining motivation for high school chemistry students enrolling in a second year chemistry course

Science.gov (United States)

Camarena, Nilda N.

A sample of 108 Pre-AP Chemistry students in Texas participated in a study to determine motivational factors for enrolling in AP Chemistry and University Chemistry. The factors measured were academic attitude, perceptions of chemistry, confidence level in chemistry, and expectations/experiences in the chemistry class. Students completed two questionnaires, one at the beginning of the year and one at the end. Four high school campuses from two school districts in Texas participated. Two campuses were traditional high schools and two were smaller magnet schools. The results from this study are able to confirm that there are definite correlations between academic attitudes, perceptions, confidence level, and experiences and a student's plans to enroll in AP and University Chemistry. The type of school as well as the student's gender seemed to have an influence on a student's plan to enroll in a second year of chemistry.

Lithium Ion Battery Chemistries from Renewable Energy Storage to Automotive and Back-up Power Applications

DEFF Research Database (Denmark)

Stan, Ana-Irina; Swierczynski, Maciej Jozef; Stroe, Daniel Ioan

2014-01-01

Lithium ion (Li-ion) batteries have been extensively used in consumer electronics because of their characteristics, such as high efficiency, long life, and high gravimetric and volumetric energy. In addition, Li-ion batteries are becoming the most attractive candidate as electrochemical storage...... systems for stationary applications, as well as power source for sustainable automotive and back-up power supply applications. This paper gives an overview of the Li-ion battery chemistries that are available at present in the market, and describes the three out of four main applications (except...... the consumers’ applications), grid support, automotive, and back-up power, for which the Li-ion batteries are suitable. Each of these applications has its own specifications and thus, the chemistry of the Li-ion battery should be chosen to fulfil the requirements of the corresponding application. Consequently...

Make-up wells drilling cost in financial model for a geothermal project

Science.gov (United States)

Oktaviani Purwaningsih, Fitri; Husnie, Ruly; Afuar, Waldy; Abdurrahman, Gugun

2017-12-01

After commissioning of a power plant, geothermal reservoir will encounter pressure decline, which will affect wells productivity. Therefore, further drilling is carried out to enhance steam production. Make-up wells are production wells drilled inside an already confirmed reservoir to maintain steam production in a certain level. Based on Sanyal (2004), geothermal power cost consists of three components, those are capital cost, O&M cost and make-up drilling cost. The make-up drilling cost component is a major part of power cost which will give big influence in a whole economical value of the project. The objective of this paper it to analyse the make-up wells drilling cost component in financial model of a geothermal power project. The research will calculate make-up wells requirements, drilling costs as a function of time and how they influence the financial model and affect the power cost. The best scenario in determining make-up wells strategy in relation with the project financial model would be the result of this research.

Plant response to nutrient availability across variable bedrock geologies

Science.gov (United States)

Castle, S.C.; Neff, J.C.

2009-01-01

We investigated the role of rock-derived mineral nutrient availability on the nutrient dynamics of overlying forest communities (Populus tremuloides and Picea engelmanni-Abies lasiocarpa v. arizonica) across three parent materials (andesite, limestone, and sandstone) in the southern Rocky Mountains of Colorado. Broad geochemical differences were observed between bedrock materials; however, bulk soil chemistries were remarkably similar between the three different sites. In contrast, soil nutrient pools were considerably different, particularly for P, Ca, and Mg concentrations. Despite variations in nutrient stocks and nutrient availability in soils, we observed relatively inflexible foliar concentrations and foliar stoichiometries for both deciduous and coniferous species. Foliar nutrient resorption (P and K) in the deciduous species followed patterns of nutrient content across substrate types, with higher resorption corresponding to lower bedrock concentrations. Work presented here indicates a complex plant response to available soil nutrients, wherein plant nutrient use compensates for variations in supply gradients and results in the maintenance of a narrow range in foliar stoichiometry. ?? 2008 Springer Science+Business Media, LLC.

Assessment of thermalhydraulic phenomena for external water make-up

International Nuclear Information System (INIS)

Harwood, C.; Baschuk, J.

2015-01-01

Following the Fukushima Daiichi accident, Canadian NPP licensees implemented a number of changes, including additional provisions for water make-up to the reactor/boiler systems. The CNSC has placed a contract with CNL to model some of the make-up options, focusing on cooling via the boilers to prevent core damage. Such strategies have been credited with sustaining thermo syphoning in the primary system and thus prolonging the available time for the operator to provide pumped make-up to the boilers or emergency coolant injection to the core, thereby maintaining decay heat removal. This paper presents results of CATHENA calculations of an extended loss of all electrical power in which the operator manually depressurizes the boilers by crash-cooling, thus allowing water to flow to the boilers by gravity from the deaerator tank. The rapid cooling of the boilers promotes thermo-syphoning flow in the primary heat transport system and results in a corresponding cool-down and depressurization of this system. (author)

Assessment of thermalhydraulic phenomena for external water make-up

Energy Technology Data Exchange (ETDEWEB)

Harwood, C., E-mail: Christopher.Harwood@cnsc-ccsn.gc.ca [Canadian Nuclear Safety Commission, Ottawa, ON (Canada); Baschuk, J. [Canadian Nuclear Laboratories, Chalk River, ON, (Canada)

2015-07-01

Following the Fukushima Daiichi accident, Canadian NPP licensees implemented a number of changes, including additional provisions for water make-up to the reactor/boiler systems. The CNSC has placed a contract with CNL to model some of the make-up options, focusing on cooling via the boilers to prevent core damage. Such strategies have been credited with sustaining thermo syphoning in the primary system and thus prolonging the available time for the operator to provide pumped make-up to the boilers or emergency coolant injection to the core, thereby maintaining decay heat removal. This paper presents results of CATHENA calculations of an extended loss of all electrical power in which the operator manually depressurizes the boilers by crash-cooling, thus allowing water to flow to the boilers by gravity from the deaerator tank. The rapid cooling of the boilers promotes thermo-syphoning flow in the primary heat transport system and results in a corresponding cool-down and depressurization of this system. (author)

Quantifying the impact cosmetic make-up has on age perception and the first impression projected.

Science.gov (United States)

Dayan, Steven H; Cho, Katherine; Siracusa, Mary; Gutierrez-Borst, Selika

2015-04-01

First impressions are lasting, consequential and defined as the immediate judgment made of another from zero acquaintance. Multiple studies have reported the benefits of cosmetic make-up. We set out to investigate the psychosocial and aesthetic effects of cosmetic make-up in order to better understand why women wear it. Twenty-seven women were recruited in order to examine the effects of cosmetic make-up on first impressions. The photographs of individual subjects wearing the control cosmetics, their own make-up, and no make-up were randomly assigned to three binders (A, B, and C). Three hundred evaluators participated (100 evaluators per book) and completed a 10-point First Impression Scale for each of the 27 photos in their binder. Statistical analysis of the collected data was conducted in SPSS using two-tailed t-tests to determine the statistical significance of the differences between first impressions of Own Make-up vs No Make-up, No Make-up vs Control Make-up, and Own Makeup vs Control Make-up. There was a significant difference in improvement in all pairings across all 8 categories in the First Impressions questionnaire particularly in perceived age between own make-up, no make-up, control make-up (41, 42, 38; Pfirst impressions, age perception, self-esteem, and the quality of life impact that cosmetic makeup has on women's appearance and confidence. Subjects wearing cosmetic make-up appeared 4 years younger than those wearing no make-up. And the control cosmetic make-up subjects on average projected a 37% better first impression than subjects wearing no make-up. We objectively quantified and qualified the benefits of applying cosmetic make-up. Make-up can reduce the perceived age, improve the first impression projected and increase the self-esteem of those who apply it.

Chemistry Notes

Science.gov (United States)

School Science Review, 1976

1976-01-01

Described are eight chemistry experiments and demonstrations applicable to introductory chemistry courses. Activities include: measure of lattice enthalpy, Le Chatelier's principle, decarboxylation of soap, use of pocket calculators in pH measurement, and making nylon. (SL)

Nutrient limitation and microbially mediated chemistry: studies using tuff inoculum obtained from the Exploratory Studies Facility, Yucca Mountain

International Nuclear Information System (INIS)

Chen, C. I.; Chuu, Y. J.; Meike, A.; Ringelberg, D.; Sawvel, A.

1998-01-01

Flow-through bioreactors are used to investigate the relationship between the supply (and limitation) of major nutrients required by microorganisms (C, N, P, S) and effluent chemistry to obtain data that can be useful to develop models of microbially mediated aqueous chemistry. The bioreactors were inoculated with crushed tuff from Yucca Mountain. Six of the 14 bioreactor experiments currently in operation have shown growth, which occurred in as few as 5 days and as much as a few months after initiation of the experiment. All of the bioreactors exhibiting growth contained glucose as a carbon source, but other nutritional components varied. Chemical signatures of each bioreactor were compared to each other and selected results were compared to computer simulations of the equivalent abiotic chemical reactions. At 21 C, the richest medium formulation produced a microbial community that lowered the effluent pH from 6.4 to as low as 3.9. The same medium formulation at 50 C produced no significant change in pH but caused a significant increase in Cl after a period of 200 days. Variations in concentrations of other elements, some of which appear to be periodic (Ca, Mg, etc.) also occur. Bioreactors fed with low C, N, P, S media showed growth, but had stabilized at lower cell densities. The room temperature bioreactor in this group exhibited a phospholipid fatty acid (PLFA) signature of sulfur- or iron-reducing bacteria, which produced a significant chemical signature in the effluent from that bioreactor. Growth had not been observed yet in the alkaline bioreactors, even in those containing glucose. The value of combining detailed chemical and community (e.g., ester-linked PLFA) analyses, long-duration experiments, and abiotic chemical models to distinguish chemical patterns is evident. Although all of the bioreactors contain the same initial microorganisms and mineral constituents, PLFA analysis demonstrates that both input chemistry and temperature determine the

Antiparallel Dynamic Covalent Chemistries.

Science.gov (United States)

Matysiak, Bartosz M; Nowak, Piotr; Cvrtila, Ivica; Pappas, Charalampos G; Liu, Bin; Komáromy, Dávid; Otto, Sijbren

2017-05-17

The ability to design reaction networks with high, but addressable complexity is a necessary prerequisite to make advanced functional chemical systems. Dynamic combinatorial chemistry has proven to be a useful tool in achieving complexity, however with some limitations in controlling it. Herein we introduce the concept of antiparallel chemistries, in which the same functional group can be channeled into one of two reversible chemistries depending on a controllable parameter. Such systems allow both for achieving complexity, by combinatorial chemistry, and addressing it, by switching from one chemistry to another by controlling an external parameter. In our design the two antiparallel chemistries are thiol-disulfide exchange and thio-Michael addition, sharing the thiol as the common building block. By means of oxidation and reduction the system can be reversibly switched from predominantly thio-Michael chemistry to predominantly disulfide chemistry, as well as to any intermediate state. Both chemistries operate in water, at room temperature, and at mildly basic pH, which makes them a suitable platform for further development of systems chemistry.

Does a Course on the History and Philosophy of Chemistry Have Any Effect on Prospective Chemistry Teachers' Perceptions? The Case of Chemistry and the Chemist

Science.gov (United States)

Sendur, G.; Polat, M.; Kazanci, C.

2017-01-01

The creative comparisons prospective chemistry teachers make about "chemistry" and the "chemist" may reflect how they perceive these concepts. In this sense, it seems important to determine which creative comparisons prospective teachers make with respect to these and how these can change after the history of chemistry is…

Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics

Science.gov (United States)

Marcarelli, Amy M.; Baxter, Colden V.; Wipfli, Mark S.

2014-01-01

Mitigation activities designed to supplement nutrient and organic matter inputs to streams experiencing decline or loss of Pacific salmon typically presuppose that an important pathway by which salmon nutrients are moved to fish (anadromous and/or resident) is via nutrient incorporation by biofilms and subsequent bottom-up stimulation of biofilm production, which is nutrient-limited in many ecosystems where salmon returns have declined. Our objective was to quantify the magnitude of nutrient incorporation and biofilm dynamics that underpin this indirect pathway in response to experimental additions of salmon carcasses and pelletized fish meal (a.k.a., salmon carcass analogs) to 500-m reaches of central Idaho streams over three years. Biofilm standing crops increased 2–8-fold and incorporated marine-derived nutrients (measured using 15N and 13C) in the month following treatment, but these responses did not persist year-to-year. Biofilms were nitrogen (N) limited before treatments, and remained N limited in analog, but not carcass-treated reaches. Despite these biofilm responses, in the month following treatment total N load was equal to 33–47% of the N added to the treated reaches, and N spiraling measurements suggested that as much as 20%, but more likely 2–3% of added N was taken up by microbes. Design of biologically and cost-effective strategies for nutrient addition will require understanding the rates at which stream microbes take up nutrients and the downstream distance traveled by exported nutrients.

Kabuki make-up syndrome with genitourinary anomalies ...

African Journals Online (AJOL)

We report a 3.5 year old male child, first in order of birth of healthy consanguineous Egyptian parents with typical characteristics of Kabuki make-up syndrome. The patient had microcephaly, high arched sparse eyebrows, hypertelorism, long palpebral fissures with eversion of the lateral third of the lower eyelids, bilateral ...

Effects of Gravel Bars on Nutrient Spiraling in Bedrock-Alluvium Streams

Science.gov (United States)

Iobst, B. R.; Carroll, E. P.; Furbish, D. J.

2007-05-01

The importance of the connection between nutrient transport and local stream geomorphology is becoming increasingly important. Studies have shown that the interconnectivity of nutrient cycles in the downstream direction is in part controlled by the distribution and size of gravel bars in low order streams, as hyporheic flow occurs dominantly through alternate and mid-channel gravel bars. For this investigation multiple gravel bars in a 3rd order bedrock-alluvium stream were studied to determine general relationships between nutrient spiraling and hyporheic flow. The first goal was to understand (1) the extent to which water moves through hyporheic zones and (2) the basic chemistry of the hyporheic water. The second part of the study was to understand how nutrients, notably nitrogen, are affected in their cycling by the relatively long residence times encountered in gravel bars during hyporheic flow. Wells were installed along a 600 m reach of Panther Creek, KY in selected bars, as well as in a secondary location involving a grid installation pattern in one large bar. Results have shown that hyporheic flow through gravel bars is an important factor in influencing stream chemistry. Background water chemistry surveys have shown that certain parameters, specifically ammonium and nitrogen concentrations vary downstream, and that the dominant control over these changes is gravel bar location. Rhodamine WT was used in field tracer tests to track the travel times of water through bars as well as partitioning of water between the open channel and hyporheic flows. Further tests will be conducted utilizing a stable isotope study to determine how nitrogen is affected by hyporheic flow, and what implications this has for nutrient transport. We expect results to show that the spacing and size of gravel bars is a dominant control in key nutrient spiraling parameters, namely uptake lengths and overall nitrogen cycling rates. This has implications for how natural systems will

Making Data Management Accessible in the Undergraduate Chemistry Curriculum

Science.gov (United States)

Reisner, Barbara A.; Vaughan, K. T. L.; Shorish, Yasmeen L.

2014-01-01

In the age of "big data" science, data management is becoming a key information literacy skill for chemistry professionals. To introduce this skill in the undergraduate chemistry major, an activity has been developed to familiarize undergraduates with data management. In this activity, students rename and organize cards that represent…

Fenton chemistry-based detemplation of an industrially relevant microcrystalline beta zeolite. Optimization and scaling-up studies

NARCIS (Netherlands)

Ortiz-Iniesta, Maria Jesus; Melian-Cabrera, Ignacio

A mild template removal of microcrystalline beta zeolite, based on Fenton chemistry, was optimized. Fenton detemplation was studied in terms of applicability conditions window, reaction rate and scale up. TGA and CHN elemental analysis were used to evaluate the detemplation effectiveness, while 'CP,

Eutrophication and contaminant data management for EU marine policies: the EMODnet Chemistry infrastructure.

Science.gov (United States)

Vinci, Matteo; Lipizer, Marina; Giorgetti, Alessandra

2016-04-01

The European Marine Observation and Data Network (EMODnet) initiative has the following purposes: to assemble marine metadata, data and products, to make these fragmented resources more easily available to public and private users and to provide quality-assured, standardised and harmonised marine data. EMODnet Chemistry was launched by DG MARE in 2009 to support the Marine Strategy Framework Directive (MSFD) requirements for the assessment of eutrophication and contaminants, following INSPIRE Directive rules. The aim is twofold: the first task is to make available and reusable the big amount of fragmented and inaccessible data, hosted in the European research institutes and environmental agencies. The second objective is to develop visualization services useful for the tasks of the MSFD. The technical set-up is based on the principle of adopting and adapting the SeaDataNet infrastructure for ocean and marine data which are managed by National Oceanographic Data Centers and relies on a distributed network of data centers. Data centers contribute to data harvesting and enrichment with the relevant metadata. Data are processed into interoperable formats (using agreed standards ISO XML, ODV) with the use of common vocabularies and standardized quality control procedures .Data quality control is a key issue when merging heterogeneous data coming from different sources and a data validation loop has been agreed within EMODnet Chemistry community and is routinely performed. After data quality control done by the regional coordinators of the EU marine basins (Atlantic, Baltic, North, Mediterranean and Black Sea), validated regional datasets are used to develop data products useful for the requirements of the MSFD. EMODnet Chemistry provides interpolated seasonal maps of nutrients and services for the visualization of time series and profiles of several chemical parameters. All visualization services are developed following OGC standards as WMS and WPS. In order to test new

Water chemistry experience following an extensive power up-rate in Oskarshamn 3 BWR

International Nuclear Information System (INIS)

Wegemar, Boerje; Nilsson, Jimmy; Lejon Johan; Bergfors, Asa; Arnberg, Bo

2012-09-01

The Swedish Oskarshamn 3 BWR plant, operated by OKG, was first connected to the grid in 1985. The plant has been power up-rated in two steps; from the original design, 3020 MWth, to 3300 MWth (109%, 1989) and recently to 3900 MWth (129%, 2009). Westinghouse Electric Sweden AB (former ASEA-Atom, OEM of the plant) was rewarded a major contract in the recently implemented up-rating project, the PULS project. The PULS project is quite unique since no operating experience has to date been reported from a similar major power up-rate in a BWR plant. Water chemistry experience from the first period of operation following the implementation of the PULS project is reported and discussed in the paper. Reported chemistry and radiochemistry measurements in feedwater (FW) and reactor water (RW) include corrosion products, activated corrosion products, dissolved oxygen and impurities like chloride, sulfate etc. Furthermore, a comparison of water quality prior to implementation of the PULS project is included. Several process systems have been modified, one of them being the condensate cleanup system (CCU), a Pre-coat filter system. The design criteria for the CCU system include the filter run-lengths, pressure drop before back-washing and requirements on water chemistry quality. The paper describes in some detail the CCU system modifications being implemented in order to fulfil the design criterion. CCU cleanup efficiency, operating temperature and influence of hydrogen peroxide on the CCU resin are all important issues being covered in the paper. As for the latter, it is well known that oxygen and hydrogen peroxide (from radiolysis in the core region) might cause partial deterioration of CCU standard cation resin resulting in increased RW sulfate concentrations. This aspect is covered in the paper as well. The reactor water cleanup system (RWCU) in Oskarshamn 3 consists of deep bed ion exchange filters (mixed bed filter). The purpose of RWCU is to maintain a low level of

Bottom Sediment Chemistry, Nutrient Balance, and Water Birds in ...

African Journals Online (AJOL)

Water bird characteristics, nutrient loadings, and the levels of bottom sediment silicon oxide (SiO2), aluminium oxide (Al2O3), ferric oxide (Fe2O3), calcium oxide (CaO), copper (Cu), phosphorus (P) and organic carbon (C) was studied in eight high altitude (2040-2640m) small shallow (0.065-0.249 km2; 0.9-3.1 m) ...

Optimizing of Make Up Air Performance for Commercial Kitchen Ventilation Improvement

Directory of Open Access Journals (Sweden)

Manshoor B.

2014-07-01

Full Text Available A commercial kitchen is a complicated environment where multiple components of a ventilation system including kitchen hood, exhaust fan, air supply, and make up air systems work together but not always in unison. For the commercial kitchen environment, make up air systems used to control the kitchen space from unwanted odor and thermal confort. Make air systems for commercial kitchen already established. However, an optimization is important to determine the most suitable make air systems and at the same time can improve the thermal comfort in the working space. In this study, a simulation work was conducted to investigate a suitable supply air velocity to optimize the make up air for kitchen ventilation system. In order to achieve the objectives, ANSYS FLUENT software (CFD was used to carry out the simulation and analysis. 3D kitchen space with 10m x 8m x 3m with air supply velocity was set to 0 m/s, 0.14 m/s, 0.28 m/s and 0.42 m/s. From the simulation work, the velocity of air flow tested which is 0.28 m/s is enough to control the heat and give an enough comfort to the working space for the size of kitchen simulated. Well implementation of the make up air in the kitchen hood can improve an air quality in the commercial kitchen and also keep the kitchen space comfortable to the workers.

Octopamine connects nutrient cues to lipid metabolism upon nutrient deprivation.

Science.gov (United States)

Tao, Jun; Ma, Yi-Cheng; Yang, Zhong-Shan; Zou, Cheng-Gang; Zhang, Ke-Qin

2016-05-01

Starvation is probably the most common stressful situation in nature. In vertebrates, elevation of the biogenic amine norepinephrine levels is common during starvation. However, the precise role of norepinephrine in nutrient deprivation remains largely unknown. We report that in the free-living nematode Caenorhabditis elegans, up-regulation of the biosynthesis of octopamine, the invertebrate counterpart of norepinephrine, serves as a mechanism to adapt to starvation. During nutrient deprivation, the nuclear receptor DAF-12, known to sense nutritional cues, up-regulates the expression of tbh-1 that encodes tyramine β-hydroxylase, a key enzyme for octopamine biosynthesis, in the RIC neurons. Octopamine induces the expression of the lipase gene lips-6 via its receptor SER-3 in the intestine. LIPS-6, in turn, elicits lipid mobilization. Our findings reveal that octopamine acts as an endocrine regulator linking nutrient cues to lipolysis to maintain energy homeostasis, and suggest that such a mechanism may be evolutionally conserved in diverse organisms.

Groundwater age and chemistry, and future nutrient loads for selected Rotorua Lakes catchments

International Nuclear Information System (INIS)

Morgenstern, U.; Reevers, R.R.; Daugney, C.J.; Cameron, S.; Gordon, D.

2005-01-01

Hydrochemical analysis and age dating of groundwater and groundwater-fed streams were carried out in the Lake Rotorua and Okareka catchments to assess the past and current states, and future trends in groundwater chemistry. The study was undertaken because of declining lake water quality due to observed increases in nutrient loads entering these lakes. THe hydrogeology of the Rotorua Lakes area can be described as a permeable pumiceous surface tephra layer that allows easy penetration of rainwater recharge to deeper rhyolite and ignimbrite aquifers. These aquifers are essentially unconfined and yield high volumes of groundwater that discharges to spring-fed streams or directly to the lake. The hydrochemistry of groundwaters is characterised by much lower concentrations of Ca, Mg and SO 4 and much higher concentrations of PO 4 -P and SiO 2 than other groundwaters in New Zealand. This chemical signature reflects the volcanic origin of the aquifer lithology. Because the aquifers in the Rotorua area have large water storage capacity there is a long residence time for nutrient-laden groundwater. It takes decades for the water after being recharged to reach the spring-fed streams and the lakes. The large groundwater bodies have therefore 'silently' been contaminated over decades, with the old pristine groundwater being progressively replaced by younger nutrient-laden water that will discharge to the spring-fed streams and finally to the lakes. This study involved age dating of springs, wells, and groundwater-fed streams to assess how long it takes for nutrient-enriched groundwater to travel from pastoral land to springs and streams, and to the lakes. Most of the springs and wells in the Lake Rotorua and Okareka catchments contained relatively old groundwaters, with mean residence times between 40 and >170 years (only two wells have younger water of 26 and 31 years mean residence time). This corresponds to young water fractions (water recharged within the last 55 years

Urbanization Changes the Temporal Dynamics of Nutrients and Water Chemistry

Science.gov (United States)

Steele, M.; Badgley, B.

2017-12-01

Recent studies find that urban development alters the seasonal dynamics of nutrient concentrations, where the highest concentrations of nitrogen occurred during the winter in urban watersheds, rather than the summer. However, the effects of urbanization on the seasonal concentrations of other nutrients and chemical components is unknown. Therefore, to determine how urbanization changes the seasonal dynamics, once a week we measured concentrations of dissolved organic carbon (DOC), nutrients (NO3, DON, TN, PO4), base cations (Ca, Mg, Na, K), anions (F, Cl, SO4), pH, sediment, temperature, conductivity, and dissolved oxygen (DO) of nine urban, agricultural, and minimally developed watersheds in southwest Virginia, USA. We found that urbanization disrupted the seasonal dynamics of all metrics, except DON, PO4, Ca, sediment, and DO, where some shifted to high concentrations during the winter (Cl, conductivity), highs during late winter or spring (DOC, Na), a season low (TN, SO4, NO3) or high (NH4) during the summer, or remained more constant throughout the year compared to the reference watersheds (Mg, K, pH). The complex changes in seasonal dynamics coincide with a decoupling of common correlations between constituents; for example, DO and NO3 are negatively correlated in reference watersheds (NO3 increases, DO decreases), but positively correlated in urban watersheds. These results suggest that as watersheds become more intensely developed, the influence of natural drivers like temperature and vegetation become steadily overcome by the influence of urban drivers like deicing salts and wastewater leakage, which exert increasing control of seasonal water quality and aquatic habitat.

USA Nutrient managment forecasting via the "Fertilizer Forecaster": linking surface runnof, nutrient application and ecohydrology.

Science.gov (United States)

Drohan, Patrick; Buda, Anthony; Kleinman, Peter; Miller, Douglas; Lin, Henry; Beegle, Douglas; Knight, Paul

2017-04-01

USA and state nutrient management planning offers strategic guidance that strives to educate farmers and those involved in nutrient management to make wise management decisions. A goal of such programs is to manage hotspots of water quality degradation that threaten human and ecosystem health, water and food security. The guidance provided by nutrient management plans does not provide the day-to-day support necessary to make operational decisions, particularly when and where to apply nutrients over the short term. These short-term decisions on when and where to apply nutrients often make the difference between whether the nutrients impact water quality or are efficiently utilized by crops. Infiltrating rainfall events occurring shortly after broadcast nutrient applications are beneficial, given they will wash soluble nutrients into the soil where they are used by crops. Rainfall events that generate runoff shortly after nutrients are broadcast may wash off applied nutrients, and produce substantial nutrient losses from that site. We are developing a model and data based support tool for nutrient management, the Fertilizer Forecaster, which identifies the relative probability of runoff or infiltrating events in Pennsylvania (PA) landscapes in order to improve water quality. This tool will support field specific decisions by farmers and land managers on when and where to apply fertilizers and manures over 24, 48 and 72 hour periods. Our objectives are to: (1) monitor agricultural hillslopes in watersheds representing four of the five Physiographic Provinces of the Chesapeake Bay basin; (2) validate a high resolution mapping model that identifies soils prone to runoff; (3) develop an empirically based approach to relate state-of-the-art weather forecast variables to site-specific rainfall infiltration or runoff occurrence; (4) test the empirical forecasting model against alternative approaches to forecasting runoff occurrence; and (5) recruit farmers from the four

Effects of mountain agriculture on nutrient cycling at upstream watersheds

Science.gov (United States)

Lin, T.-C.; Shaner, P. L.; Wang, L.-J.; Shih, Y.-T.; Wang, C.-P.; Huang, G.-H.; Huang, J.-C.

2015-05-01

The expansion of agriculture to rugged mountains can exacerbate negative impacts of agriculture activities on ecosystem function. In this study, we monitored streamwater chemistry of four watersheds with varying proportions of agricultural lands (0.4, 3, 17, 22%) and rainfall chemistry of two of the four watersheds at Feitsui Reservoir Watershed in northern Taiwan to examine the effects of agriculture on watershed nutrient cycling. We found that the greater the proportions of agricultural lands, the higher the ion concentrations, which is evident for fertilizer-associated ions (NO3-, K+) but not for ions that are rich in soils (SO42-, Ca2+, Mg2+), suggesting that agriculture enriched fertilizer-associated nutrients in streamwater. The watershed with the highest proportion of agricultural lands had higher concentrations of ions in rainfall and lower nutrient retention capacity (i.e. higher output-input ratio of ions) compared to the relatively pristine watershed, suggesting that agriculture can influence atmospheric deposition of nutrients and a system's ability to retain nutrients. Furthermore, we found that a forested watershed downstream of agricultural activities can dilute the concentrations of fertilizer-associated ions (NO3-, K+) in streamwater by more than 70%, indicating that specific landscape configurations help mitigate nutrient enrichment to aquatic systems. We estimated that agricultural lands at our study site contributed approximately 400 kg ha-1 yr-1 of NO3-N and 260 kg ha-1 yr-1 of PO4-P output via streamwater, an order of magnitude greater than previously reported around the globe and can only be matched by areas under intense fertilizer use. Furthermore, we re-constructed watershed nutrient fluxes to show that excessive leaching of N and P, and additional loss of N to the atmosphere via volatilization and denitrification, can occur under intense fertilizer use. In summary, this study demonstrated the pervasive impacts of agriculture activities

Titration and HPLC Characterization of Kombucha Fermentation: A Laboratory Experiment in Food Analysis

Science.gov (United States)

Miranda, Breanna; Lawton, Nicole M.; Tachibana, Sean R.; Swartz, Natasja A.; Hall, W. Paige

2016-01-01

Quantification of the many constituents that make up our food, whether they are desirable (vitamins, antioxidants, nutrients) or undesirable (pesticides, toxins), is one of the most practical applications of chemistry. In this study, kombucha, a popular fermented tea beverage, was analyzed using acid-base titration and high-performance liquid…

Wood-ash addition on a drained forest peatland in Southern Sweden - Effects on water chemistry; Tillfoersel av biobra ensleaska i tallskog paa en dikad torvmark i soedra Sverige - Effekter paa vattenkemin

Energy Technology Data Exchange (ETDEWEB)

Ring, Eva; Broemssen, Claudia von; Losjoe, Katarina; Sikstroem Ulf

2012-02-15

Wood ash can be used for forest fertilization on peatlands or for nutrient compensation following intensive harvesting. This project was performed in order to investigate effects on water chemistry of applying wood ash to a Scots pine stand on a drained peatland. Ditch-water chemistry was monitored before and after the application of wood ash. Furthermore, groundwater was collected and chemically analyzed both from the ash-treated peatland and from an adjacent untreated reference peatland. Both short term (a few months) and more long term effects (up to three years after application) were detected on water chemistry

Nutrient acquisition strategies of mammalian cells.

Science.gov (United States)

Palm, Wilhelm; Thompson, Craig B

2017-06-07

Mammalian cells are surrounded by diverse nutrients, such as glucose, amino acids, various macromolecules and micronutrients, which they can import through transmembrane transporters and endolysosomal pathways. By using different nutrient sources, cells gain metabolic flexibility to survive periods of starvation. Quiescent cells take up sufficient nutrients to sustain homeostasis. However, proliferating cells depend on growth-factor-induced increases in nutrient uptake to support biomass formation. Here, we review cellular nutrient acquisition strategies and their regulation by growth factors and cell-intrinsic nutrient sensors. We also discuss how oncogenes and tumour suppressors promote nutrient uptake and thereby support the survival and growth of cancer cells.

Nutrient cycling in a strongly acidified mesotrophic lake

Czech Academy of Sciences Publication Activity Database

Kopáček, Jiří; Brzáková, Martina; Hejzlar, Josef; Nedoma, Jiří; Porcal, Petr; Vrba, Jaroslav

2004-01-01

Roč. 49, č. 4 (2004), s. 1202-1213 ISSN 0024-3590 R&D Projects: GA ČR(CZ) GA206/00/0063; GA ČR(CZ) GA206/03/1583 Institutional research plan: CEZ:AV0Z6017912 Keywords : acidification * nutrients * water chemistry Subject RIV: DA - Hydrology ; Limnology Impact factor: 3.024, year: 2004

Reaction-Map of Organic Chemistry

Science.gov (United States)

Murov, Steven

2007-01-01

The Reaction-Map of Organic Chemistry lists all the most commonly studied reactions in organic chemistry on one page. The discussed Reaction-Map will act as another learning aide for the students, making the study of organic chemistry much easier.

Effects of liming on forage availability and nutrient content in a forest impacted by acid rain.

Directory of Open Access Journals (Sweden)

Sarah E Pabian

Full Text Available Acidic deposition and subsequent forest soil acidification and nutrient depletion can affect negatively the growth, health and nutrient content of vegetation, potentially limiting the availability and nutrient content of forage for white-tailed deer (Odocoileus virginianus and other forest herbivores. Liming is a mitigation technique that can be used to restore forest health in acidified areas, but little is known about how it affects the growth or nutrient content of deer forage. We examined the effects of dolomitic limestone application on the growth and chemical composition of understory plants in an acidified forest in central Pennsylvania, with a focus on vegetative groups included as white-tailed deer forage. We used a Before-After-Control-Impact study design with observations 1 year before liming and up to 5 years post-liming on 2 treated and 2 untreated 100-ha sites. Before liming, forage availability and several nutrients were below levels considered optimal for white-tailed deer, and many vegetative characteristics were related to soil chemistry. We observed a positive effect of liming on forb biomass, with a 2.7 fold increase on limed sites, but no biomass response in other vegetation groups. We observed positive effects of liming on calcium and magnesium content and negative effects on aluminum and manganese content of several plant groups. Responses to liming by forbs and plant nutrients show promise for improving vegetation health and forage quality and quantity for deer.

Proximate and ultimate controls on carbon and nutrient dynamics of small agricultural catchments

Science.gov (United States)

Thomas, Zahra; Abbott, Benjamin W.; Troccaz, Olivier; Baudry, Jacques; Pinay, Gilles

2016-03-01

Direct and indirect effects from human activity have dramatically increased nutrient loading to aquatic inland and estuarine ecosystems. Despite an abundance of studies investigating the impact of agricultural activity on water quality, our understanding of what determines the capacity of a watershed to remove or retain nutrients remains limited. The goal of this study was to identify proximate and ultimate controls on dissolved organic carbon and nutrient dynamics in small agricultural catchments by investigating the relationship between catchment characteristics, stream discharge, and water chemistry. We analyzed a 5-year, high-frequency water chemistry data set from three catchments in western France ranging from 2.3 to 10.8 km2. The relationship between hydrology and solute concentrations differed between the three catchments and was associated with hedgerow density, agricultural activity, and geology. The catchment with thicker soil and higher surface roughness had relatively invariant carbon and nutrient chemistry across hydrologic conditions, indicating high resilience to human disturbance. Conversely, the catchments with smoother, thinner soils responded to both intra- and interannual hydrologic variation with high concentrations of phosphate (PO43-) and ammonium (NH4+) in streams during low flow conditions and strong increases in dissolved organic carbon (DOC), sediment, and particulate organic matter during high flows. Despite contrasting agricultural activity between catchments, the physical context (geology, topography, and land-use configuration) appeared to be the most important determinant of catchment solute dynamics based on principle components analysis. The influence of geology and accompanying topographic and geomorphological factors on water quality was both direct and indirect because the distribution of agricultural activity in these catchments is largely a consequence of the geologic and topographic context. This link between inherent

The Interaction Between Dynamics and Chemistry of Ozone in the Set-up Phase of the Northern Hemisphere Polar Vortex

Science.gov (United States)

Kawa, S. R.; Bevilacqua, R.; Margitan, J. J.; Douglass, A. R.; Schoeberl, M. R.; Hoppel, K.; Sen, B.; Bhartia, P. K. (Technical Monitor)

2001-01-01

The morphology and evolution of the stratospheric ozone (O3) distribution at high latitudes in the Northern Hemisphere (NH) are examined for the late summer and fall seasons of 1999. This time period sets the O3 initial condition for the SOLVE/THESEO field mission performed during winter 1999-2000. In situ and satellite data are used along with a three-dimensional model of chemistry and transport (CTM) to determine the key processes that control the distribution of O3 in the lower-to-middle stratosphere. O3 in the vortex at the beginning of the winter season is found to be nearly constant from 500 to above 800 K with a value at 3 ppmv +/- approx. 10%. Values outside the vortex are up to a factor of 2 higher and increase significantly with potential temperature. The seasonal time series of data from POAM shows that relatively low O3 mixing ratios, which characterize the vortex in late fall, are already present at high latitudes at the end of summer before the vortex circulation sets up. Analysis of the CTM output shows that the minimum O3 and increase in variance in late summer are the result of: 1) stirring of polar concentric O3 gradients by nascent wave-driven transport, and 2) an acceleration of net photochemical loss with decreasing solar illumination. The segregation of low O3 mixing ratios into the vortex as the circulation strengthens through the fall suggests a possible feedback role between O3 chemistry and the vortex formation dynamics. Trajectory calculations from O3 sample points early in the fall, however, show only a weak correlation between initial O3 mixing ratio and potential vorticity later in the season consistent with order-of-magnitude calculations for the relative importance of O3 in the fall radiative balance at high latitudes. The possible connection between O3 chemistry and the dynamics of vortex formation does suggest that these feedbacks and sensitivities need to be better understood in order to make confident predictions of the recovery

Dynamics of forest soil chemistry

Energy Technology Data Exchange (ETDEWEB)

Alveteg, M

1998-11-01

Acidification caused by emissions of nitrogen and sulphur and associated adverse effects on forest ecosystems has been an issue on the political agenda for decades. Temporal aspects of soil acidification and/or recovery can be investigated using the soil chemistry model SAFE, a dynamic version of the steady-state model PROFILE used in critical loads assessment on the national level, e.g. for Sweden. In this thesis, possibilities to replace the use of apparent gibbsite solubility coefficients with a more mechanistic Al sub-model are investigated and a reconstruction model, MAKEDEP, is presented which makes hindcasts and forecasts of atmospheric deposition and nutrient uptake and cycling. A regional application of SAFE/MAKEDEP based on 622 sites in Switzerland is also presented. It is concluded that the quantitative information on pools and fluxes of Al in forest ecosystems is very limited and that there currently exists no mechanistic alternative in modelling soil solution Al. MAKEDEP is a valuable and operational tool for deriving input to dynamic soil chemistry models such as SMART, MAGIC and SAFE. For multi-layer models, e.g. the SAFE model, including nutrient cycling in MAKEDEP is shown to be important. The strength of the regional assessment strategy presented in this thesis lies in its transparency and modularity. All sub-modules, including models, transfer functions, assumptions in the data acquisition strategy, etc., can be checked and replaced individually. As the presented assessment strategy is based on knowledge and data from a wide range of scientists and fields it is of vital importance that the research community challenge the assumptions made. The many measurable intermediate results produced by the included models will hopefully encourage scientists to challenge the models through additional measurements at the calculation sites. It is concluded that current reduction plans are not sufficient for all forest ecosystems in Switzerland to recover from

Effects of the hippopotamus on the chemistry and ecology of a changing watershed.

Science.gov (United States)

Stears, Keenan; McCauley, Douglas J; Finlay, Jacques C; Mpemba, James; Warrington, Ian T; Mutayoba, Benezeth M; Power, Mary E; Dawson, Todd E; Brashares, Justin S

2018-05-29

Cross-boundary transfers of nutrients can profoundly shape the ecology of recipient systems. The common hippopotamus, Hippopotamus amphibius , is a significant vector of such subsidies from terrestrial to river ecosystems. We compared river pools with high and low densities of H. amphibius to determine how H. amphibius subsidies shape the chemistry and ecology of aquatic communities. Our study watershed, like many in sub-Saharan Africa, has been severely impacted by anthropogenic water abstraction reducing dry-season flow to zero. We conducted observations for multiple years over wet and dry seasons to identify how hydrological variability influences the impacts of H. amphibius During the wet season, when the river was flowing, we detected no differences in water chemistry and nutrient parameters between pools with high and low densities of H. amphibius Likewise, the diversity and abundance of fish and aquatic insect communities were indistinguishable. During the dry season, however, high-density H. amphibiu s pools differed drastically in almost all measured attributes of water chemistry and exhibited depressed fish and insect diversity and fish abundance compared with low-density H. amphibius pools. Scaled up to the entire watershed, we estimate that H. amphibius in this hydrologically altered watershed reduces dry-season fish abundance and indices of gamma-level diversity by 41% and 16%, respectively, but appears to promote aquatic invertebrate diversity. Widespread human-driven shifts in hydrology appear to redefine the role of H. amphibius , altering their influence on ecosystem diversity and functioning in a fashion that may be more severe than presently appreciated.

Advanced chemistry management system to optimize BWR chemistry control

International Nuclear Information System (INIS)

Maeda, K.; Nagasawa, K.

2002-01-01

BWR plant chemistry control has close relationships among nuclear safety, component reliability, radiation field management and fuel integrity. Advanced technology is required to improve chemistry control [1,3,6,7,10,11]. Toshiba has developed TACMAN (Toshiba Advanced Chemistry Management system) to support BWR chemistry control. The TACMAN has been developed as response to utilities' years of requirements to keep plant operation safety, reliability and cost benefit. The advanced technology built into the TACMAN allows utilities to make efficient chemistry control and to keep cost benefit. TACMAN is currently being used in response to the needs for tools those plant chemists and engineers could use to optimize and identify plant chemistry conditions continuously. If an incipient condition or anomaly is detected at early stage, root causes evaluation and immediate countermeasures can be provided. Especially, the expert system brings numerous and competitive advantages not only to improve plant chemistry reliability but also to standardize and systematize know-how, empirical knowledge and technologies in BWR chemistry This paper shows detail functions of TACMAN and practical results to evaluate actual plant. (authors)

Making Students Eat Their Greens: Information Skills for Chemistry Students

Science.gov (United States)

George, Sarah; Munshi, Tasnim

2016-01-01

Employers are increasingly requiring a range of "soft" skills from chemistry graduates, including the ability to search for and critically evaluate information. This paper discusses the issues around encouraging chemistry students to engage with information skills and suggests curricular changes which may help to "drip-feed"…

Fisheries management under nutrient influence

DEFF Research Database (Denmark)

Hammarlund, Cecilia; Nielsen, Max; Waldo, Staffan

2018-01-01

A fisheries management model that identifies the economic optimal management of fisheries under the influence of nutrients is presented. The model starts from the idea that growth in fish biomass increases with increasing availability of nutrients owing to higher food availability up to a peak...

Continental-scale effects of nutrient pollution on stream ecosystem functioning.

Science.gov (United States)

Woodward, Guy; Gessner, Mark O; Giller, Paul S; Gulis, Vladislav; Hladyz, Sally; Lecerf, Antoine; Malmqvist, Björn; McKie, Brendan G; Tiegs, Scott D; Cariss, Helen; Dobson, Mike; Elosegi, Arturo; Ferreira, Verónica; Graça, Manuel A S; Fleituch, Tadeusz; Lacoursière, Jean O; Nistorescu, Marius; Pozo, Jesús; Risnoveanu, Geta; Schindler, Markus; Vadineanu, Angheluta; Vought, Lena B-M; Chauvet, Eric

2012-06-15

Excessive nutrient loading is a major threat to aquatic ecosystems worldwide that leads to profound changes in aquatic biodiversity and biogeochemical processes. Systematic quantitative assessment of functional ecosystem measures for river networks is, however, lacking, especially at continental scales. Here, we narrow this gap by means of a pan-European field experiment on a fundamental ecosystem process--leaf-litter breakdown--in 100 streams across a greater than 1000-fold nutrient gradient. Dramatically slowed breakdown at both extremes of the gradient indicated strong nutrient limitation in unaffected systems, potential for strong stimulation in moderately altered systems, and inhibition in highly polluted streams. This large-scale response pattern emphasizes the need to complement established structural approaches (such as water chemistry, hydrogeomorphology, and biological diversity metrics) with functional measures (such as litter-breakdown rate, whole-system metabolism, and nutrient spiraling) for assessing ecosystem health.

Aqueous Solution Chemistry of Plutonium

Energy Technology Data Exchange (ETDEWEB)

Clark, David L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-01-28

Things I have learned working with plutonium: Chemistry of plutonium is complex; Redox equilibria make Pu solution chemistry particularly challenging in the absence of complexing ligands; Understanding this behavior is key to successful Pu chemistry experiments; There is no suitable chemical analog for plutonium.

Research-Based Development of a Lesson Plan on Shower Gels and Musk Fragrances Following a Socio-Critical and Problem-Oriented Approach to Chemistry Teaching

Science.gov (United States)

Marks, Ralf; Eilks, Ingo

2010-01-01

A case is described of the development of a lesson plan for 10th grade (age range 15-16) chemistry classes on the chemistry of shower gels. The lesson plan follows a socio-critical and problem-oriented approach to chemistry teaching. This means that, aside from learning about the basic chemistry of the components making up modern shower gels in…

Making Chemistry Relevant to the Engineering Major

Science.gov (United States)

Basu-Dutt, Sharmistha; Slappey, Charles; Bartley, Julie K.

2010-01-01

As part of a campus-wide, externally funded project to increase performance in, enthusiasm for, and retention within STEM disciplines, we developed an interdisciplinary, team-taught first-year seminar course. The construction and delivery of this course was designed to show the relevance of selected general chemistry topics such as matter and…

Design of make-up water system for Tehran research reactor spent nuclear fuels storage pool

Energy Technology Data Exchange (ETDEWEB)

Aghoyeh, Reza Gholizadeh [Reactor Research Group, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI), North Amirabad, P.O. Box 14155-1339, Tehran (Iran, Islamic Republic of); Khalafi, Hosein, E-mail: hkhalafi@aeoi.org.i [Reactor Research Group, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI), North Amirabad, P.O. Box 14155-1339, Tehran (Iran, Islamic Republic of)

2010-10-15

Spent nuclear fuels storage (SNFS) is an essential auxiliary system in nuclear facility. Following discharge from a nuclear reactor, spent nuclear fuels have to be stored in water pool of SNFS away from reactor to allow for radioactive to decay and removal of generated heat. To prevent corrosion damage of fuels and other equipments, the storage pool is filled with de-ionized water which serves as moderator, coolant and shielding. The de-ionized water will be provided from make-up water system. In this paper, design of a make-up water system for optimal water supply and its chemical properties in SNFS pool is presented. The main concern of design is to provide proper make-up water throughout the storage time. For design of make-up water system, characteristics of activated carbon purifier, anionic, cationic and mixed-bed ion-exchangers have been determined. Inlet water to make-up system provide from Tehran municipal water system. Regulatory Guide 1.13 of the and graver company manual that manufactured the Tehran research reactor (TRR) make-up water system have been used for make-up water system of TRR spent nuclear fuels storage pool design.

Design of make-up water system for Tehran research reactor spent nuclear fuels storage pool

International Nuclear Information System (INIS)

Aghoyeh, Reza Gholizadeh; Khalafi, Hosein

2010-01-01

Spent nuclear fuels storage (SNFS) is an essential auxiliary system in nuclear facility. Following discharge from a nuclear reactor, spent nuclear fuels have to be stored in water pool of SNFS away from reactor to allow for radioactive to decay and removal of generated heat. To prevent corrosion damage of fuels and other equipments, the storage pool is filled with de-ionized water which serves as moderator, coolant and shielding. The de-ionized water will be provided from make-up water system. In this paper, design of a make-up water system for optimal water supply and its chemical properties in SNFS pool is presented. The main concern of design is to provide proper make-up water throughout the storage time. For design of make-up water system, characteristics of activated carbon purifier, anionic, cationic and mixed-bed ion-exchangers have been determined. Inlet water to make-up system provide from Tehran municipal water system. Regulatory Guide 1.13 of the and graver company manual that manufactured the Tehran research reactor (TRR) make-up water system have been used for make-up water system of TRR spent nuclear fuels storage pool design.

Growing your green chemistry mindset

Science.gov (United States)

Kosmas, Steven

2017-08-01

The purpose of this article is not to delineate the steps to move across the continuum to being a greener chemist, but to analyse the cognitive processes involved in fostering a green chemistry growth mindset (GCGM) [Dweck C. (2006) Mindset: The New Psychology of Success. New York, NY: Ballatine]. The focus is on changing the mindset, which inevitably will lead to a more mindful approach to chemistry practices before the laboratory begins. A green chemistry fixed mindset (GCFM) is closed to making improvements, since the attitude is that the techniques and processes in the laboratory are already employing a green chemistry mindset [Dweck C. (2006) Mindset: The New Psychology of Success. New York, NY: Ballatine]. The problem with the GCFM is that it precludes the possibility of making improvements. However, the GCGM employs a continuous, intentional focus on the attitude towards green chemistry, with the ultimate goal being a change in chemistry practices that is greener. The focus of this article will be on the GCGM.

Making Students Eat Their Greens: Information Skills for Chemistry Students

Directory of Open Access Journals (Sweden)

Sarah George

2016-12-01

Full Text Available Employers are increasingly requiring a range of "soft" skills from chemistry graduates, including the ability to search for and critically evaluate information. This paper discusses the issues around encouraging chemistry students to engage with information skills and suggests curricular changes which may help to "drip-feed" information skills into degree programs.

Plant nutrient supply and movement. Report of a panel

Energy Technology Data Exchange (ETDEWEB)

NONE

1965-11-01

Despite the emphasis given by the Agency to the more practical field experimentation in agriculture like soil fertility and fertilizer utilization, it is obvious that any long-term programme of soil fertility research must also take into account the fundamentals of plant nutrient supply and movement. Thus a large gap exists between the present methods used for predicting the response of a crop to fertilizer on any given soil and fundamental knowledge in soil physics, chemistry and biology. Only when precise determinations can be made of the quantity of ions in the soil solution, the adsorption complex, and the rate at which the exchange processes occur, will it be possible to develop a scientific basis for the evaluation of the nutrient status of soils and to make efficient fertilizer recommendations. Study of these processes, and others, such as ion movement as affected by water flow and diffusion phenomena, have been carried out on a very limited scale by individual scientists in widely separated institutes. Comparative lack of progress in this field is, at least in part, due to the absence of co-ordinated planning and exchange of information among scientists working on these problems, and it is for this reason that this meeting has been organized by the Agency. From the research point of view a co-ordinated research contract programme on plant nutrient supply and movement has already been initiated and at present there are six contractors. An essential feature of the programme is co-ordination, and this Panel partly represents the second planning meeting of these contractors. The discussions will, however, have wider scope, as other acknowledged specialists in the subject are participating in this Panel.

Nutrient analysis explained for non-chemists by using interactive e-learning material

NARCIS (Netherlands)

Busstra, M.C.; Hulshof, P.J.M.; Houwen, J.; Elburg, L.; Hollman, P.C.H.

2012-01-01

The diverse educational and professional background of individuals involved in food composition data work presents challenges in their training. In particular, it is difficult to explain chemical analysis of nutrients to individuals lacking a background in chemistry. Therefore an interactive

Domestic science: making chemistry your cup of tea.

Science.gov (United States)

Keene, Melanie

2008-03-01

In the early Victorian home, there were plenty of scientific lessons to be uncovered. With the appropriate interrogation, everyday objects could transform seemingly mundane activities such as eating breakfast, washing clothes or reading by candle-light into household lectures that gave children a familiar base from which to explore the hidden properties and marvellous histories of common commodities. Responding to an unprecedented hunger for scientific knowledge, a profusion of introductory texts appeared in the mid-nineteenth century that directed lessons into homes across Britain and beyond. In particular, the science of chemistry found its way into this domestic setting, as writers promoted its practice and practitioners as a source of authoritative expertise on everyday life. One of the most compelling illustrations of this encounter between the public and chemistry took place over a simple cup of tea.

Transport of biologically important nutrients by wind in an eroding cold desert

Science.gov (United States)

Sankey, Joel B.; Germino, Matthew J.; Benner, Shawn G.; Glenn, Nancy F.; Hoover, Amber N.

2012-01-01

Wind erosion following fire is an important landscape process that can result in the redistribution of ecologically important soil resources. In this study we evaluated the potential for a fire patch in a desert shrubland to serve as a source of biologically important nutrients to the adjacent, downwind, unburned ecosystem. We analyzed nutrient concentrations (P, K, Ca, Mg, Cu, Fe, Mn, Al) in wind-transported sediments, and soils from burned and adjacent unburned surfaces, collected during the first to second growing seasons after a wildfire that burned in 2007 in Idaho, USA in sagebrush steppe; a type of cold desert shrubland. We also evaluated the timing of potential wind erosion events and weather conditions that might have contributed to nutrient availability in downwind shrubland. Findings indicated that post-fire wind erosion resulted in an important, but transient, addition of nutrients on the downwind shrubland. Aeolian sediments from the burned area were enriched relative to both the up- and down-wind soil and indicated the potential for a fertilization effect through the deposition of the nutrient-enriched sediment during the first, but not second, summer after wildfire. Weather conditions that could have produced nutrient transport events might have provided increased soil moisture necessary to make nutrients accessible for plants in the desert environment. Wind transport of nutrients following fire is likely important in the sagebrush steppe as it could contribute to pulses of resource availability that might, for example, affect plant species differently depending on their phenology, and nutrient- and water-use requirements.

The party political make-up of EU legislative bodies.

NARCIS (Netherlands)

Warntjen, Andreas; Hix, Simon; Crombez, Christophe

2008-01-01

This research note provides an overview of the party political make-up of EU legislative bodies for the period 1979-2004 (Commission: 1979-2007) in terms of the left-right and pro-/anti-Europe dimensions. The various methods of measuring political positions are discussed and compared. Measures for

Hide out return test and blowndown crud composition under ETA chemistry

International Nuclear Information System (INIS)

Chocron, Mauricio; Rodriguez, Ivanna; Saucedo, Ramona; Rodriguez-Aliciardi, Matias; Montes, Juan

2012-09-01

Among the techniques recommended for the surveillance of the Steam Generators (SGs) are (i) the follow-up of the corrosion products in the Feed Water and Blown down water and the corresponding accumulation mass balance and (ii) The follow-up of ionic impurities normally present in the main condensate and feed water that can enter the cycle either by condenser leakages or even by the make-up water. This is so, no matter how well the the cycle is constructed or the make-up water plant behaves given the continuous phase change present in it and the subsequent concentration. A synergistic effect exists between both, corrosion products and impurities, (i) and (ii), because impurities concentrate in the deposits creating a potentially risky environment for the steam generator tubes. Hide out return determination consists in the measurement of the concentration of ions, anions and cations, present in the blown-down water which are eluted during the shutdown along with the reduction of power and temperature. The integrated value provides figures to perform several evaluations like: (i) how well the make-up water plant has performed during the cycle, (ii) presence of condenser in leakages, (iii) amount of deposits present in the steam generator and (iv) it allows to estimate the chemistry in operation inside the steam generator liquid phase inside the sludge pile. Embalse, a CANDU 6 pressurized heavy water reactor located in Cordoba Province, Argentina, is close to reach the end-of-design-life and a project of life extension is currently ongoing. There, also the chemistry in the BOP has been modified from Morpholine to Ethanolamine chemistry (Fernandez et. al, NPC'2010, October 3-7, Quebec City, Canada) to enhance protection of steam generator internals and new steam generators will be installed. It is of interest then to set up a hide-out return procedure and analysis of blown down crud collected during the shut down as a base line for the second period of operation

Our nutrient world. The challenge to produce more food & energy with less pollution

NARCIS (Netherlands)

Sutton, M.A.; Bleeker, A.; Howard, C.M.; Erisman, J.W.; Abrol, Y.P.; Bekunda, M.; Datta, A.; Davidson, E.; Vries, de W.; Oenema, O.; Zhang, F.S.

2013-01-01

The message of this overview is that everyone stands to benefit from nutrients and that everyone can make a contribution to promote sustainable production and use of nutrients. Whether we live in a part of the world with too much or too little nutrients, our daily decisions can make a difference.

30 CFR 872.26 - What are minimum program make up funds?

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false What are minimum program make up funds? 872.26 Section 872.26 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT, DEPARTMENT OF THE... your jurisdiction. (c) We will make funds available to the States of Missouri and Tennessee under this...

Concept-Oriented Task Design: Making Purposeful Case Comparisons in Organic Chemistry

Science.gov (United States)

Graulich, Nicole; Schween, Michael

2018-01-01

Acquiring conceptual understanding seems to be one of the main challenges students face when studying organic chemistry. Traditionally, organic chemistry presents an extensive variety of chemical transformations, which often lead students to recall an organic transformation rather than apply conceptual knowledge. Strong surface level focus and…

Coolant make-up device for BWR type reactor

International Nuclear Information System (INIS)

Sasagawa, Hiroshi.

1994-01-01

In a coolant make-up device, an opening of a pressure equalizing pipeline in a pressure vessel is disposed in coolants above a reactor core and below a usual fluctuation range of a reactor vessel water level. Further, a float check valve is disposed to the pressure equalizing pipeline for preventing coolants in the pressure vessel flowing into the pipeline. If the water level in the pressure vessel is lowered than the setting position for the float check valve, the float drops by its own weight to open the opening of the pressure equalizing pipeline. Then, steams in the pressure vessel are flown into the pipeline, to equalize the pressure between a coolant storage tank and the pressure vessel of the reactor. Coolants in the coolant storage tank is injected to the pressure vessel by way of the water injection pipeline due to the difference of the pressure head between the water level in the coolants storage tank and the water level in the pressure vessel. If the coolants are lowered than the setting position for the float check value, the float check valve does not close unless the water level is recovered to the setting position for the float valve and, accordingly, the coolant make-up is continued. (N.H.)

Throughfall and stemflow chemistry in a northern hardwood forest

Energy Technology Data Exchange (ETDEWEB)

Eaton, J S; Likens, G E; Bormann, F H

1973-01-01

The contribution of throughfall and stemflow as pathways of the intrasystem nutrient cycle within the forested Hubbard Brook ecosystem was investigated. Nutrients followed were Ca, Mg, K, Na, NO/sub 3/, SO/sub 4/, NH/sub 4/, Fl, PO/sub 4/, H, organic N, and organic matter. Variation in throughfall and stemflow chemistry were determined under American beech, sugar maple, and yellow birch, the three major species comprising the forest studied. Nutrients generally recognized as being associated with organic molecules (e.g. P, N) moved more slowly from the forest canopy to the forest floor. These nutrients moved out of the canopy primarily via litterfall. Nutrients more commonly found in an ionic form (e.g. K) were found to move very rapidly from the forest canopy to the available nutrient pool in throughfall and stemflow. A comparison is made between the amount of each nutrient present in the forest canopy and the amount of these nutrients found in the throughfall and stemflow. The importance of hydrogen ion exchange in the removal of cations from the forest canopy is shown. Precipitation of low pH probably acts to accelerate the intrasystem cycling of nutrients within forested ecosystems. Total nutrient removal from the forest canopy by throughfall and stemflow is presented along with a comparison with the removal by litterfall.

Groundwater impacts on surface water quality and nutrient loads in lowland polder catchments: monitoring the greater Amsterdam area

Science.gov (United States)

Yu, Liang; Rozemeijer, Joachim; van Breukelen, Boris M.; Ouboter, Maarten; van der Vlugt, Corné; Broers, Hans Peter

2018-01-01

The Amsterdam area, a highly manipulated delta area formed by polders and reclaimed lakes, struggles with high nutrient levels in its surface water system. The polders receive spatially and temporally variable amounts of water and nutrients via surface runoff, groundwater seepage, sewer leakage, and via water inlets from upstream polders. Diffuse anthropogenic sources, such as manure and fertiliser use and atmospheric deposition, add to the water quality problems in the polders. The major nutrient sources and pathways have not yet been clarified due to the complex hydrological system in lowland catchments with both urban and agricultural areas. In this study, the spatial variability of the groundwater seepage impact was identified by exploiting the dense groundwater and surface water monitoring networks in Amsterdam and its surrounding polders. A total of 25 variables (concentrations of total nitrogen (TN), total phosphorus (TP), NH4, NO3, HCO3, SO4, Ca, and Cl in surface water and groundwater, N and P agricultural inputs, seepage rate, elevation, land-use, and soil type) for 144 polders were analysed statistically and interpreted in relation to sources, transport mechanisms, and pathways. The results imply that groundwater is a large source of nutrients in the greater Amsterdam mixed urban-agricultural catchments. The groundwater nutrient concentrations exceeded the surface water environmental quality standards (EQSs) in 93 % of the polders for TP and in 91 % for TN. Groundwater outflow into the polders thus adds to nutrient levels in the surface water. High correlations (R2 up to 0.88) between solutes in groundwater and surface water, together with the close similarities in their spatial patterns, confirmed the large impact of groundwater on surface water chemistry, especially in the polders that have high seepage rates. Our analysis indicates that the elevated nutrient and bicarbonate concentrations in the groundwater seepage originate from the decomposition of

Groundwater impacts on surface water quality and nutrient loads in lowland polder catchments: monitoring the greater Amsterdam area

Directory of Open Access Journals (Sweden)

L. Yu

2018-01-01

Full Text Available The Amsterdam area, a highly manipulated delta area formed by polders and reclaimed lakes, struggles with high nutrient levels in its surface water system. The polders receive spatially and temporally variable amounts of water and nutrients via surface runoff, groundwater seepage, sewer leakage, and via water inlets from upstream polders. Diffuse anthropogenic sources, such as manure and fertiliser use and atmospheric deposition, add to the water quality problems in the polders. The major nutrient sources and pathways have not yet been clarified due to the complex hydrological system in lowland catchments with both urban and agricultural areas. In this study, the spatial variability of the groundwater seepage impact was identified by exploiting the dense groundwater and surface water monitoring networks in Amsterdam and its surrounding polders. A total of 25 variables (concentrations of total nitrogen (TN, total phosphorus (TP, NH4, NO3, HCO3, SO4, Ca, and Cl in surface water and groundwater, N and P agricultural inputs, seepage rate, elevation, land-use, and soil type for 144 polders were analysed statistically and interpreted in relation to sources, transport mechanisms, and pathways. The results imply that groundwater is a large source of nutrients in the greater Amsterdam mixed urban–agricultural catchments. The groundwater nutrient concentrations exceeded the surface water environmental quality standards (EQSs in 93 % of the polders for TP and in 91 % for TN. Groundwater outflow into the polders thus adds to nutrient levels in the surface water. High correlations (R2 up to 0.88 between solutes in groundwater and surface water, together with the close similarities in their spatial patterns, confirmed the large impact of groundwater on surface water chemistry, especially in the polders that have high seepage rates. Our analysis indicates that the elevated nutrient and bicarbonate concentrations in the groundwater seepage originate

Determination of the algal growth-limiting nutrients in strip mine ponds

International Nuclear Information System (INIS)

Bucknavage, M.J.; Aharrah, E.C.

1984-01-01

Using both a test organism, Ankistrodesmus falcatus, and natural phytoplankton, the Printz Algal Assay Bottle Test was used to determine the algal growth limiting nutrients in two strip mine ponds. Nitrogen, phosphorus, and iron were investigated, singly and in combination, as possible limiting nutrients. A synthetic chelator, Na 2 EDTA, was also used in the assay to test for the presence of metal toxicants and/or trace metal limitation. Because bacteria have a major influence on water chemistry, a separate assay incorporating the natural bacteria population was performed. In both ponds, assay results using test alga indicate phosphorus to be the primary limiting nutrient and nitrogen as a secondary factor. The presence of EDTA in combination with phosphate containing treatment promoted a higher algal concentration in both ponds. Iron was determined to be a secondary limiting nutrient in only one of the ponds. Natural phytoplankton of the two ponds responded in a similar manner to nutrient increases. Only one pond had the same results produced by both assays. Nutrient availability was influenced by the presence of bacteria in one pond but not in the other

Effects of mountain tea plantations on nutrient cycling at upstream watersheds

Science.gov (United States)

Lin, T.-C.; Shaner, P.-J. L.; Wang, L.-J.; Shih, Y.-T.; Wang, C.-P.; Huang, G.-H.; Huang, J.-C.

2015-11-01

The expansion of agriculture to rugged mountains can exacerbate negative impacts of agricultural activities on ecosystem function. In this study, we monitored streamwater and rainfall chemistry of mountain watersheds at the Feitsui Reservoir Watershed in northern Taiwan to examine the effects of agriculture on watershed nutrient cycling. We found that the greater the proportion of tea plantation cover, the higher the concentrations of fertilizer-associated ions (NO3-, K+) in streamwater of the four mountain watersheds examined; on the other hand, the concentrations of the ions that are rich in soils (SO42-, Ca2+, Mg2+) did not increase with the proportion of tea plantation cover, suggesting that agriculture enriched fertilizer-associated nutrients in streamwater. Of the two watersheds for which rainfall chemistry was available, the one with higher proportion of tea plantation cover had higher concentrations of ions in rainfall and retained less nitrogen in proportion to input compared to the more pristine watershed, suggesting that agriculture can influence atmospheric deposition of nutrients and a system's ability to retain nutrients. As expected, we found that a forested watershed downstream of agricultural activities can dilute the concentrations of NO3- in streamwater by more than 70 %, indicating that such a landscape configuration helps mitigate nutrient enrichment in aquatic systems even for watersheds with steep topography. We estimated that tea plantation at our study site contributed approximately 450 kg ha-1 yr-1 of NO3-N via streamwater, an order of magnitude greater than previously reported for agricultural lands around the globe, which can only be matched by areas under intense fertilizer use. Furthermore, we constructed watershed N fluxes to show that excessive leaching of N, and additional loss to the atmosphere via volatilization and denitrification can occur under intense fertilizer use. In summary, this study demonstrated the pervasive impacts of

Parameterization of dust emissions in the global atmospheric chemistry-climate model EMAC: impact of nudging and soil properties

OpenAIRE

Astitha, M.; Lelieveld, J.; Kader, M. Abdel; Pozzer, A.; de Meij, A.

2012-01-01

Airborne desert dust influences radiative transfer, atmospheric chemistry and dynamics, as well as nutrient transport and deposition. It directly and indirectly affects climate on regional and global scales. Two versions of a parameterization scheme to compute desert dust emissions are incorporated into the atmospheric chemistry general circulation model EMAC (ECHAM5/MESSy2.41 Atmospheric Chemistry). One uses a global...

Water chemistry regimes for VVER-440 units: water chemistry influence on fuel cladding behaviour

International Nuclear Information System (INIS)

Zmitko, M.

1999-01-01

In this lecture next problems of water chemistry influence on fuel cladding behaviour for VVER-440 units are presented: primary coolant technologies; water chemistry specification and control; fuel integrity considerations; zirconium alloys cladding corrosion (corrosion versus burn-up; water chemistry effect; crud deposition; hydrogen absorption; axial offset anomaly); alternatives for the primary coolant regimes

Ask the experts: the challenges and benefits of flow chemistry to optimize drug development.

Science.gov (United States)

Anderson, Neal; Gernaey, Krist V; Jamison, Timothy F; Kircher, Manfred; Wiles, Charlotte; Leadbeater, Nicholas E; Sandford, Graham; Richardson, Paul

2012-09-01

Against a backdrop of a struggling economic and regulatory climate, pharmaceutical companies have recently been forced to develop new ways to provide more efficient technology to meet the demands of a competitive drug industry. This issue, coupled with an increase in patent legislation and a rising generics market, makes these themes common issues in the growth of drug development. As a consequence, the importance of process chemistry and scale-up has never been more under the spotlight. Future Medicinal Chemistry wishes to share the thoughts and opinions of a variety of experts from this field, discussing issues concerning the use of flow chemistry to optimize drug development, the potential regulatory and environmental challenges faced with this, and whether the academic and industrial sectors could benefit from a more harmonized system relevant to process chemistry.

[Making up tuberculosis risk groups from decreed contingents].

Science.gov (United States)

Kucherov, A L; Il'icheva, E Iu

2001-01-01

The paper provides materials to make up risk groups from decreed contingents by using the database developed and introduced in the Novomoskovsk district, as well as a programme for rapid determination of the risk of tuberculosis. This procedure reduces a scope of fluorographic surveys among the decreed contingents, as well as their expenditures by 60%. Moreover, it may be useful for professional choice in the employment of the decreed persons, which may promote a decrease in the incidence of tuberculosis among them.

Costume and make up in cultural development | Abuku | Creative ...

African Journals Online (AJOL)

Costume is an essential feature of any dramatic production and with make- up constitutes the total visual appearance of the actor. Costume is an important fact of acting; therefore it is not mere covering for an actor. Thus its essence is rooted in the fact that the actor wears it, moves and speaks in it and is continually within the ...

Medicinal chemistry and the pharmacy curriculum.

Science.gov (United States)

Khan, M O Faruk; Deimling, Michael J; Philip, Ashok

2011-10-10

The origins and advancements of pharmacy, medicinal chemistry, and drug discovery are interwoven in nature. Medicinal chemistry provides pharmacy students with a thorough understanding of drug mechanisms of action, structure-activity relationships (SAR), acid-base and physicochemical properties, and absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles. A comprehensive understanding of the chemical basis of drug action equips pharmacy students with the ability to answer rationally the "why" and "how" questions related to drug action and it sets the pharmacist apart as the chemical expert among health care professionals. By imparting an exclusive knowledge base, medicinal chemistry plays a vital role in providing critical thinking and evidence-based problem-solving skills to pharmacy students, enabling them to make optimal patient-specific therapeutic decisions. This review highlights the parallel nature of the history of pharmacy and medicinal chemistry, as well as the key elements of medicinal chemistry and drug discovery that make it an indispensable component of the pharmacy curriculum.

Using the Arts To Make Chemistry Accessible to Everybody. 2002 James Flack Norris Award, sponsored by ACS Northeast Section

Science.gov (United States)

Lerman, Zafra M.

2003-11-01

Although all chemists know the importance of chemistry in daily life, the rest of the population somehow does not seem to share this view. Each of us believes that we must teach chemistry to everyone, yet we have not succeeded in persuading everyone that they must study chemistry. The reason is often the methods used to communicate chemistry to the public. The arts (music, dance, drama, fine arts, etc.) are excellent vehicles to enhance understanding. For eample, most people are not interested in the concept of the ionic bond, but when presented like Shakespeare's Romeo and Juliet (with a love story between Sodium and Chlorine) everyone enjoys learning about the bonding relationship. In addition, the drama students who write and act out the script remember the concept far longer than would be expected through more conventional teaching methods. The same is true for the students who wrote and acted The Bondfather, and for the students who danced The Three States of Matter. (Our hero falls in love with Solid, but "When she warms to him, through his fingers she runs," and when his love heats up with Liquid, "Her love escaped from him just like a vapor.")

NREL, NASA, and UCL Team Up to Make Lithium-Ion Batteries Safer on Earth

Science.gov (United States)

(NASA) and University College London (UCL) for a cutting-edge study on lithium-ion (Li-ion) battery and in Space | News | NREL NREL, NASA, and UCL Team Up to Make Lithium-Ion Batteries Safer on Earth and in Space NREL, NASA, and UCL Team Up to Make Lithium-Ion Batteries Safer on Earth and in Space

Process analytical chemistry applied to actinide waste streams

International Nuclear Information System (INIS)

Day, R.S.

1994-01-01

The Department of Energy is being called upon to clean up it's legacy of waste from the nuclear complex generated during the cold war period. Los Alamos National Laboratory is actively involved in waste minimization and waste stream polishing activities associated with this clean up. The Advanced Testing Line for Actinide Separations (ATLAS) at Los Alamos serves as a developmental test bed for integrating flow sheet development of nitric acid waste streams with process analytical chemistry and process control techniques. The wastes require processing in glove boxes because of the radioactive components, thus adding to the difficulties of making analytical measurements. Process analytical chemistry methods provide real-time chemical analysis in support of existing waste stream operations and enhances the development of new waste stream polishing initiatives. The instrumentation and methods being developed on ATLAS are designed to supply near-real time analyses on virtually all of the chemical parameters found in nitric acid processing of actinide waste. These measurements supply information on important processing parameters including actinide oxidation states, free acid concentration, interfering anions and metal impurities

Nutrient utilisation and blood chemistry of Red Sokoto bucks fed on diets with different inclusion levels of raw and soaked roselle (Hibiscus sabdariffa L. seeds

Directory of Open Access Journals (Sweden)

Taofik Adam Ibrahim

2018-04-01

Full Text Available This study evaluated nutrient utilisation and blood chemistry of Red Sokoto bucks fed a 10 and 20 % inclusion level of raw, water- and lime-soaked Hibiscus sabdariffa L. seeds in rice bran based diets. 21 Red Sokoto bucks aged 8–10 months and weighing 9–13 kg were randomly allotted into six treatments with three bucks each, while a seventh dietary treatment with zero inclusion of seeds served as control in a 2 × 3 factorial arrangement using a complete randomised design. The results indicated that increase in dietary inclusion levels of soaked H. sabdariffa seeds increased (P < 0.05 the nutrient utilisation of bucks as compared to the control, while a decrease was observed with increasing dietary inclusion levels of raw seeds. Dietary inclusion of both raw and water-soaked H. sabdariffa seeds increased (P < 0.05 the packed cell volume. Soaking also influenced the white blood cell value which increased with increasing inclusion levels of H. sabdariffa seeds. However, values of haemoglobin and red blood cells were only affected by 20 % inclusion of raw and water-soaked H. sabdariffa seeds (P < 0.05 compared to control. Inclusion of H. sabdariffa seeds furthermore reduced serum protein, albumin, globulin, glucose and urea levels compared to control. It is therefore concluded that H. sabdariffa seeds support haematopoiesis in Red Sokoto bucks. While both inclusion levels of water-soaked and 10 % raw H. sabdariffa seeds improved nutrient utilisation compared to control and 20 % inclusion of raw seeds, the 20 % inclusion of water-soaked H. sabdariffa seeds recorded the best nitrogen utilisation efficiency.

Environmental status of the Lake Michigan region. Volume 3. Chemistry of Lake Michigan

Energy Technology Data Exchange (ETDEWEB)

Torrey, M S

1976-05-01

The report is a synoptic review of data collected over the past twenty years on the chemistry of Lake Michigan. Changes in water quality and sediment chemistry, attributable to cultural and natural influences, are considered in relation to interacting processes and factors controlling the distribution and concentration of chemical substances within the Lake. Temperature, light, and mixing processes are among the important natural influences that affect nutrient cycling, dispersal of pollutants, and fate of materials entering the Lake. Characterization of inshore-offshore and longitudinal differences in chemical concentrations and sediment chemistry for the main body of the Lake is supplemented by discussion of specific areas such as Green Bay and Grand Traverse Bay. Residues, specific conductance, dissolved oxygen, major and trace nutrients, and contaminants are described in the following context: biological essentiality and/or toxicity, sources to the Lake, concentrations in the water column and sediments, chemical forms, seasonal variations and variation with depth. A summary of existing water quality standards, statutes, and criteria applicable to Lake Michigan is appended.

Beneficial changes in food consumption and nutrient intake after 10 years of follow-up in a Mediterranean cohort: the SUN project

Directory of Open Access Journals (Sweden)

Carmen de la Fuente-Arrillaga

2016-03-01

Full Text Available Abstract Background The assessment of changes in dietary habits provides interesting information on whether or not the observed trends are in line with accepted nutritional guidelines. The objective was to evaluate within-subject longitudinal changes in food consumption and nutrient intake and in a 10-year follow-up study. Methods The SUN (Seguimiento Universidad de Navarra project is a prospective Spanish cohort study. Diet was assessed using a 136-item food-frequency questionnaire (FFQ, previously validated in Spain. The participants were 3036 university graduates (55.8 % women of Spain and the main outcome measures the changes in dietary quality and in food consumption and nutrient intake. Paired t-tests and conditional logistic regression models were used to evaluate within-subject longitudinal dietary changes and the risk of inadequacy respectively, after 10 years of follow-up. Results During follow-up, participants showed a relevant and significant increase (p < 0.001 in the consumption of fruits (7.4 %, vegetables (8.6 %, low-fat dairy products (35.2 %, lean meat (12.4 %, fish (2.9 %, whole grains (53.2 %, nuts (52.4 % and a significant decrease in legumes (−7.4 %, whole-fat dairy products (−44.2 %, red meat (−17.6 %, sugar-sweetened beverages (−58.7 % and wine (−11.9 %. With respect to nutrients, we found a higher proportion of carbohydrates (3.6 % and fiber (7.4 % and a decrease in total energy intake (2.7 %, total fat (−4.5 %, SFA (−9.4 %, MUFA (−4.9 %, PUFA (−12.7 %, w-3 and w-6 fatty acids (−9.1 and −20.5 % respectively and cholesterol (−9.6 %. Conclusions In this Mediterranean cohort study, mainly beneficial changes in the consumption of most foods and macronutrients were observed after 10 years of follow-up.

Student Attitudes toward Flipping the General Chemistry Classroom

Science.gov (United States)

Smith, J. Dominic

2013-01-01

The idea of ''flipping the classroom'' to make class time more engaging and student-centred has gained ground in recent years. The lecture portion of General Chemistry I and General Chemistry II courses were pushed outside the classroom using pre-recording technology and streaming delivery of content, in order to make in-class time more…

Recovery of nutrients from biogas digestate with biochar and clinoptilolite

NARCIS (Netherlands)

Kocaturk, N.P.

2016-01-01

The liquid fraction of digestate contains nutrients which makes it a valuable fertiliser in agricultural crop production systems. However, direct application of digestate may raise practical and environmental problems. Therefore, processes to concentrate nutrients have been proposed aiming not

Graduate Career-Making and Business Start-Up: A Literature Review

Science.gov (United States)

Nabi, Ghulam; Holden, Rick; Walmsley, Andreas

2006-01-01

Purpose: The purpose of this article is to provide a selective review of literature on the career-related decision-making processes in terms of the transition from student to business start-up, and the nature and influence of support and guidance. Design/methodology/approach: Primarily, a critical review of a range of recently published literature…

Modelling stratospheric chemistry in a global three-dimensional chemical transport model

Energy Technology Data Exchange (ETDEWEB)

Rummukainen, M [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

1996-12-31

Numerical modelling of atmospheric chemistry aims to increase the understanding of the characteristics, the behavior and the evolution of atmospheric composition. These topics are of utmost importance in the study of climate change. The multitude of gases and particulates making up the atmosphere and the complicated interactions between them affect radiation transfer, atmospheric dynamics, and the impacts of anthropogenic and natural emissions. Chemical processes are fundamental factors in global warming, ozone depletion and atmospheric pollution problems in general. Much of the prevailing work on modelling stratospheric chemistry has so far been done with 1- and 2-dimensional models. Carrying an extensive chemistry parameterisation in a model with high spatial and temporal resolution is computationally heavy. Today, computers are becoming powerful enough to allow going over to 3-dimensional models. In order to concentrate on the chemistry, many Chemical Transport Models (CTM) are still run off-line, i.e. with precalculated and archived meteorology and radiation. In chemistry simulations, the archived values drive the model forward in time, without interacting with the chemical evolution. This is an approach that has been adopted in stratospheric chemistry modelling studies at the Finnish Meteorological Institute. In collaboration with the University of Oslo, a development project was initiated in 1993 to prepare a stratospheric chemistry parameterisation, fit for global 3-dimensional modelling. This article presents the parameterisation approach. Selected results are shown from basic photochemical simulations

Modelling stratospheric chemistry in a global three-dimensional chemical transport model

Energy Technology Data Exchange (ETDEWEB)

Rummukainen, M. [Finnish Meteorological Inst., Sodankylae (Finland). Sodankylae Observatory

1995-12-31

Numerical modelling of atmospheric chemistry aims to increase the understanding of the characteristics, the behavior and the evolution of atmospheric composition. These topics are of utmost importance in the study of climate change. The multitude of gases and particulates making up the atmosphere and the complicated interactions between them affect radiation transfer, atmospheric dynamics, and the impacts of anthropogenic and natural emissions. Chemical processes are fundamental factors in global warming, ozone depletion and atmospheric pollution problems in general. Much of the prevailing work on modelling stratospheric chemistry has so far been done with 1- and 2-dimensional models. Carrying an extensive chemistry parameterisation in a model with high spatial and temporal resolution is computationally heavy. Today, computers are becoming powerful enough to allow going over to 3-dimensional models. In order to concentrate on the chemistry, many Chemical Transport Models (CTM) are still run off-line, i.e. with precalculated and archived meteorology and radiation. In chemistry simulations, the archived values drive the model forward in time, without interacting with the chemical evolution. This is an approach that has been adopted in stratospheric chemistry modelling studies at the Finnish Meteorological Institute. In collaboration with the University of Oslo, a development project was initiated in 1993 to prepare a stratospheric chemistry parameterisation, fit for global 3-dimensional modelling. This article presents the parameterisation approach. Selected results are shown from basic photochemical simulations

Can nutrient enrichment influence the invasion of Phragmites australis?

Science.gov (United States)

Uddin, Md Nazim; Robinson, Randall William

2018-02-01

Plant invasion and nutrient enrichment because of anthropogenic landscape modifications seriously threaten native plant community diversity in aquatic and wetland ecosystems. It is poorly understood, however, whether these two disturbances interact with the functional identity of recipient native plants to drive community change. We performed combined studies in the fields and greenhouse to examine whether nutrient enrichment may trigger the invasion of Phragmites australis in wetlands through competitive advantage over native Melaleuca ericifolia. Chemical characterizations of rhizosphere water were distinguished in two different nutrient enriched wetlands associated with and without Phragmites over the seasons. Significant changes in rhizosphere water were observed in invaded area compared to uninvaded area at both sites. High nitrogen (NO 3 - ), phosphorous (PO 4 3- ), dissolved organic carbon, phenolics contents, with low pH were found in invaded areas compared to uninvaded areas. Total biomass of Phragmites was positively regressed with rhizosphere water nitrogen (NO 3 - ) and phosphorous (PO 4 3- ) content. Nutrient addition significantly enhanced the growth and competitive ability of Phragmites over Melaleuca. In contrast, Melaleuca was significantly less competitive than Phragmites. There was a significantly positive correlation between the growth of Phragmites grown alone and its competitive ability. The findings in greenhouse studies coupled with characteristics of Phragmites and its' rhizosphere chemistry in the nutrient enriched fields suggest that nutrient enrichment may enhance Phragmites invasion through correspondingly increasing growth and maintaining inherent competitive advantages of Phragmites. Nutrient management could limit the vigorous growth of Phragmites in wetlands and thereby reduce invasion through competitive advantages over natives, which might have important management implications for wetland managers. Copyright © 2017. Published by

Korean Kimchi Chemistry: A Multicultural Chemistry Connection

Science.gov (United States)

Murfin, Brian

2009-01-01

Connecting science with different cultures is one way to interest students in science, to relate science to their lives, and at the same time to broaden their horizons in a variety of ways. In the lesson described here, students make kimchi, a delicious and popular Korean dish that can be used to explore many important chemistry concepts,…

Kinetic start-up performance of two large treatment plants for nutrient removal

DEFF Research Database (Denmark)

Haarbo, A.; Harremoës, Poul; Thirsing, C.

2001-01-01

In 1987 an action plan was passed in the Danish Parliament demanding a considerable reduction of the discharge of nutrients to the aquatic environment in Denmark. Consequently, the two largest wastewater treatment plants in the Copenhagen area had to be upgraded to include nutrient removal....... For more than 8 years an extensive effort has been made to determine an optimum solution for this upgrading from a technical and financial point of view. The work included six years of comprehensive pilot plant investigations with the aim of thoroughly studying and interpreting the kinetics...... of the processes involved. The investigations revealed valuable information particularly concerning limitations of the nitrification process. Consequently, the investigations contributed to an expectation of no unforeseen problems during the implementation of the upgraded plants. This paper presents the results...

Research on water chemistry in a nuclear power plant

International Nuclear Information System (INIS)

Chae, Sung Ki; Yang, Kyung Rin; Kang, Hi Dong; Koo, Je Hyoo; Hwang, Churl Kew; Lee, Eun Hee; Han, Jung Ho; Kim, Uh Chul; Kim, Joung Soo; Song, Myung Ho; Lee, Deok Hyun; Jeong, Jong Hwan

1986-12-01

To prevent the corrosion problems on important components of nuclear power plants, the computerization methods of water chemistry and the analyses of corrosion failures were studied. A preliminary study on the computerization of water chemistry log-sheet data was performed using a personal computer with dBASE-III and LOTUS packages. Recent technical informations on a computerized online chemistry data management system which provides an efficient and thorough method of system-wide monitoring of utility's secondary side chemistry were evaluated for the application to KEPCO's nuclear power plants. According to the evaluation of water chemistry data and eddy current test results, it was likely that S/G tube defect type was pitting. Pitting is believed to result from excess oxygen in make-up and air ingress, sea-water ingress bycondenser leak, and copper in sludge. A design of a corrosion tests apparatus for the tests under simulated operational conditions, such as water chemistry, water flow, high temperature and pressure, etc., of the plant has been completed. The completion of these apparatus will make it possible to do corrosion tests under the conditions mentioned above to find out the cause of corrosion failures, and to device a counter measure to these. The result of corrosion tests with alloy-600 showed that the initiation of pits occurred most severely around 175 deg C which is lower than plant-operation temperature(300 deg C) while their propagation rate had trend to be maximum around 90 deg C. It was conformed that the use of Cu-base alloys in a secondary cooling system accelerates the formation of pits by the leaking of sea-water and expected that the replacement of them can reduce the failures of S/G tubes by pitting. Preliminary works on the examination of pit-formed specimens with bare eyes, a metallurgical microscope and a SEM including EDAX analysis were done for the future use of these techniques to investigate S/G tubes. Most of corrosion products

¿Are stse contents contained in chemistry textbooks?

Directory of Open Access Journals (Sweden)

Diana Lineth Parga Lozano

2015-01-01

Full Text Available This article presents the results of a research developed in the Masters in Chemistry Education at the Universidad Pedagogica Nacional de Colombia, in Bogota 2014. In this research the presence of STSE contents in five Colombian Chemistry textbooks for tenth grade was typified. Four analysis categories were defined considering whether in the teaching of Chemistry contents, “STSE grafts”, contents through STSE, pure STSE contents, or a cross-curricular approach of them were presented. This characterization shows a curriculum limited to the discipline, with some traces of STSE approach principles within the defined categories. These contents are resources that ignore aspects of S&,T image, such as the historicalepistemological and the social, ethical, and moral implications of Chemistry, the activities proposed may cause that teaching chemistry makes little sense for students, and do not encourage participation in decision-making.

Herbivory and eutrophication mediate grassland plant nutrient responses across a global climatic gradient

Science.gov (United States)

Anderson, T. Michael; Griffith, Daniel M.; Grace, James B.; Lind, Eric M.; Adler, Peter B.; Biederman, Lori A.; Blumenthal, Dana M.; Daleo, Pedro; Firn, Jennifer; Hagenah, Nicole; Harpole, W. Stanley; MacDougall, Andrew S.; McCulley, Rebecca L.; Prober, Suzanne M.; Risch, Anita C.; Sankaran, Mahesh; Schütz, Martin; Seabloom, Eric W.; Stevens, Carly J.; Sullivan, Lauren; Wragg, Peter; Borer, Elizabeth T.

2018-01-01

Plant stoichiometry, the relative concentration of elements, is a key regulator of ecosystem functioning and is also being altered by human activities. In this paper we sought to understand the global drivers of plant stoichiometry and compare the relative contribution of climatic vs. anthropogenic effects. We addressed this goal by measuring plant elemental (C, N, P and K) responses to eutrophication and vertebrate herbivore exclusion at eighteen sites on six continents. Across sites, climate and atmospheric N deposition emerged as strong predictors of plot‐level tissue nutrients, mediated by biomass and plant chemistry. Within sites, fertilization increased total plant nutrient pools, but results were contingent on soil fertility and the proportion of grass biomass relative to other functional types. Total plant nutrient pools diverged strongly in response to herbivore exclusion when fertilized; responses were largest in ungrazed plots at low rainfall, whereas herbivore grazing dampened the plant community nutrient responses to fertilization. Our study highlights (1) the importance of climate in determining plant nutrient concentrations mediated through effects on plant biomass, (2) that eutrophication affects grassland nutrient pools via both soil and atmospheric pathways and (3) that interactions among soils, herbivores and eutrophication drive plant nutrient responses at small scales, especially at water‐limited sites.

Development of massively parallel quantum chemistry program SMASH

International Nuclear Information System (INIS)

Ishimura, Kazuya

2015-01-01

A massively parallel program for quantum chemistry calculations SMASH was released under the Apache License 2.0 in September 2014. The SMASH program is written in the Fortran90/95 language with MPI and OpenMP standards for parallelization. Frequently used routines, such as one- and two-electron integral calculations, are modularized to make program developments simple. The speed-up of the B3LYP energy calculation for (C 150 H 30 ) 2 with the cc-pVDZ basis set (4500 basis functions) was 50,499 on 98,304 cores of the K computer

Environmental Chemistry Division annual report, 1989

International Nuclear Information System (INIS)

Newman, L.

1990-01-01

The research activities making up the programs in the Environmental Chemistry Division of the Department of Applied Science are presented. Some of the more significant accomplishments during 1989 are described and plans for 1990 are discussed briefly. Publications for the period are listed and abstracts are provided. Research objectives and principal investigators are given for each of the active programs. A list of personnel and collaborators during the past year is presented. The support distribution of FY 1989 is approximately 85% from the Department of Energy (65% Office of Health and Environmental Research), and 15% other agencies (principally from the Electric Power Research Institute)

Chemistry: Who are you? Where are you going? How do we catch up with you?

OpenAIRE

Talanquer, Vicente

2009-01-01

This paper presents a personal reflection on the nature of Chemistry, its potential areas of development in the 21st century, and the corresponding implications for chemistry education. Beyond reflecting about basic characteristics of Chemistry as a science and speculating on future research trends in this discipline, the central goal of this essay is to motivate chemistry teachers and instructors, as well as chemical educators, to question the relevance and validity of the current general ch...

Synchrotron X-ray micro-beam studies of ancient Egyptian make-up

International Nuclear Information System (INIS)

Martinetto, P.; Anne, M.; Dooryhee, E.; Drakopoulos, M.; Dubus, M.; Salomon, J.; Simionovici, A.; Walter, Ph.

2001-01-01

Vases full of make-up are most often present in the burial furniture of Egyptian tombs dated from the pharaonic period. The powdered cosmetics made of isolated grains are analysed to identify their trace element signature. From this signature we identify the provenance of the mineral ingredients in the make-up and we observe different impurities in products, which have been demonstrated as synthetic substances by previous works. Focused X-ray micro-beam (2x5 μm 2 ) is successively tuned at 11 keV, below the L III absorption edge of Pb, and 31.8 keV for global characterisation of the metal impurities. The fluorescence signal integrated over each single grain is detected against the X-ray micro-diffraction pattern collected in transmission with a bi-dimensional detector. Furthermore, for galena grains rich in Zn, the XANES signal at the K-absorption edge of Zn shows its immediate nearest-neighbour environment

Synchrotron X-ray micro-beam studies of ancient Egyptian make-up

Science.gov (United States)

Martinetto, P.; Anne, M.; Dooryhée, E.; Drakopoulos, M.; Dubus, M.; Salomon, J.; Simionovici, A.; Walter, Ph.

2001-07-01

Vases full of make-up are most often present in the burial furniture of Egyptian tombs dated from the pharaonic period. The powdered cosmetics made of isolated grains are analysed to identify their trace element signature. From this signature we identify the provenance of the mineral ingredients in the make-up and we observe different impurities in products, which have been demonstrated as synthetic substances by previous works. Focused X-ray micro-beam ( 2×5 μm2) is successively tuned at 11 keV, below the L III absorption edge of Pb, and 31.8 keV for global characterisation of the metal impurities. The fluorescence signal integrated over each single grain is detected against the X-ray micro-diffraction pattern collected in transmission with a bi-dimensional detector. Furthermore, for galena grains rich in Zn, the XANES signal at the K-absorption edge of Zn shows its immediate nearest-neighbour environment.

Synchrotron X-ray micro-beam studies of ancient Egyptian make-up

Energy Technology Data Exchange (ETDEWEB)

Martinetto, P; Anne, M; Dooryhee, E; Drakopoulos, M; Dubus, M; Salomon, J; Simionovici, A; Walter, Ph

2001-07-01

Vases full of make-up are most often present in the burial furniture of Egyptian tombs dated from the pharaonic period. The powdered cosmetics made of isolated grains are analysed to identify their trace element signature. From this signature we identify the provenance of the mineral ingredients in the make-up and we observe different impurities in products, which have been demonstrated as synthetic substances by previous works. Focused X-ray micro-beam (2x5 {mu}m{sup 2}) is successively tuned at 11 keV, below the L{sub III} absorption edge of Pb, and 31.8 keV for global characterisation of the metal impurities. The fluorescence signal integrated over each single grain is detected against the X-ray micro-diffraction pattern collected in transmission with a bi-dimensional detector. Furthermore, for galena grains rich in Zn, the XANES signal at the K-absorption edge of Zn shows its immediate nearest-neighbour environment.

A new theory of plant-microbe nutrient competition resolves inconsistencies between observations and model predictions.

Science.gov (United States)

Zhu, Qing; Riley, William J; Tang, Jinyun

2017-04-01

Terrestrial plants assimilate anthropogenic CO 2 through photosynthesis and synthesizing new tissues. However, sustaining these processes requires plants to compete with microbes for soil nutrients, which therefore calls for an appropriate understanding and modeling of nutrient competition mechanisms in Earth System Models (ESMs). Here, we survey existing plant-microbe competition theories and their implementations in ESMs. We found no consensus regarding the representation of nutrient competition and that observational and theoretical support for current implementations are weak. To reconcile this situation, we applied the Equilibrium Chemistry Approximation (ECA) theory to plant-microbe nitrogen competition in a detailed grassland 15 N tracer study and found that competition theories in current ESMs fail to capture observed patterns and the ECA prediction simplifies the complex nature of nutrient competition and quantitatively matches the 15 N observations. Since plant carbon dynamics are strongly modulated by soil nutrient acquisition, we conclude that (1) predicted nutrient limitation effects on terrestrial carbon accumulation by existing ESMs may be biased and (2) our ECA-based approach may improve predictions by mechanistically representing plant-microbe nutrient competition. © 2016 by the Ecological Society of America.

Ideal and saturated soil fertility as bench marks in nutrient management; 1 outline of the framework

NARCIS (Netherlands)

Janssen, B.H.; Willigen, de P.

2006-01-01

This paper presents a framework for nutrient management that takes sustainable soil fertility, environmental protection and balanced plant nutrition as starting points, and integrates concepts from plant physiology, soil chemistry and agronomy. The framework is meant as a tool that can be applied

Philosophy of Science and Philosophy of Chemistry

OpenAIRE

Jaap van Brakel

2014-01-01

In this paper I assess the relation between philosophy of chemistry and (general) philosophy of science, focusing on those themes in the philosophy of chemistry that may bring about major revisions or extensions of current philosophy of science. Three themes can claim to make a unique contribution to philosophy of science: first, the variety of materials in the (natural and artificial) world; second, extending the world by making new stuff; and, third, specific features of the relations betwe...

Serving the medicinal chemistry community with Royal Society of Chemistry cheminformatics platforms

OpenAIRE

Williams, Antony

2015-01-01

The Royal Society of Chemistry (RSC) is a major participant in providing access to chemistry related data via the web. As an internationally renowned society for the chemical sciences, a scientific publisher and the host of the ChemSpider database for the community, RSC continues to make dramatic strides in providing online access to data. ChemSpider provides access to over 30 million chemicals sourced from over 500 data suppliers and linked out to related information on the web. The platform...

33 CFR 96.220 - What makes up a safety management system?

Science.gov (United States)

2010-07-01

... system? 96.220 Section 96.220 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY VESSEL OPERATING REGULATIONS RULES FOR THE SAFE OPERATION OF VESSELS AND SAFETY MANAGEMENT SYSTEMS Company and Vessel Safety Management Systems § 96.220 What makes up a safety management system? (a) The...

Effective follow-up consultations: the importance of patient-centered communication and shared decision making.

Science.gov (United States)

Brand, Paul L P; Stiggelbout, Anne M

2013-12-01

Paediatricians spend a considerable proportion of their time performing follow-up visits for children with chronic conditions, but they rarely receive specific training on how best to perform such consultations. The traditional method of running a follow-up consultation is based on the doctor's agenda, and is problem-oriented. Patients and parents, however, prefer a patient-centered, and solution-focused approach. Although many physicians now recognize the importance of addressing the patient's perspective in a follow-up consultation, a number of barriers hamper its implementation in practice, including time constraints, lack of appropriate training, and a strong tradition of the biomedical, doctor-centered approach. Addressing the patient's perspective successfully can be achieved through shared decision making, clinicians and patients making decisions together based on the best clinical evidence. Research shows that shared decision making not only increases patient, parent, and physician satisfaction with the consultation, but also may improve health outcomes. Shared decision making involves building a physician-patient-parent partnership, agreeing on the problem at hand, laying out the available options with their benefits and risks, eliciting the patient's views and preferences on these options, and agreeing on a course of action. Shared decision making requires specific communication skills, which can be learned, and should be mastered through deliberate practice. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of Fallow Genealogical Cycles on the Build-up of Nutrients in ...

African Journals Online (AJOL)

Dr Osondu

2012-01-04

Jan 4, 2012 ... soil nutrients was attributed to the increased in tree size, vegetation cover and adequate ground cover ... regeneration of fallow vegetation with diverse tree ...... Semi-Deciduous Forest following Anthropogenic ... Dynamics under Shifting Cultivation in Eastern ... World Bank, Washington, DC, 226–230.

The slow birth of green chemistry

Energy Technology Data Exchange (ETDEWEB)

Amato, I.

1993-03-12

Mainstream chemistry is beginning to look at environmental chemistry as an important solution to environmental problems. This can include research into developing cleaner-burning liquid fuels, cleaning up oil spills, or developing better process methods which engender less pollution, as opposed to previous practices of detecting pollutants without preventing their release to begin with. This article discusses the progress of this chemistry discipline, describes some of the ongoing research, and describes the future for environmental chemistry. An impetus for future growth will be generational change, as young scientists in training are beginning to push faculities into creating programs for environmental chemistry.

Impact of harvesting and atmospheric pollution on nutrient depletion of eastern US hardwood forests

Science.gov (United States)

M.B. Adams; J.A. Burger; A.B. Jenkins; L. Zelazny

2000-01-01

The eastern hardwood forests of the US may be threatened by the changing atmospheric chemistry and by changes in harvesting levels. Many studies have documented accelerated base cation losses with intensive forest harvesting. Acidic deposition can also alter nutrient cycling in these forests. The combination of increased harvesting, shorter rotations, and more...

Editorial: Nanoscience makes catalysis greener

KAUST Repository

Polshettiwar, Vivek; Basset, Jean-Marie; Astruc, Didier

2012-01-01

Green chemistry by nanocatalysis: Catalysis is a strategic field of science because it involves new ways of meeting energy and sustainability challenges. The concept of green chemistry, which makes the science of catalysis even more creative, has

The global nutrient challenge. From science to public engagement

Energy Technology Data Exchange (ETDEWEB)

Sutton, M.A.; Howard, C.M. [NERC Centre for Ecology and Hydrology, Edinburgh (United Kingdom); Bleeker, A. [Energy research Centre of the Netherlands, Petten (Netherlands); Datta, A. [United Nations Environment Programme, Nairobi (Kenya)

2013-04-15

Among the many environment and development challenges facing humanity, it is fair to say that nutrients do not currently feature so regularly in the newspapers, radio and television. The media tends to prefer easy single issues which affect our daily lives in a clear-cut way. The role of carbon in climate change is a good example. We all depend on climate. Burning fossil fuels makes more carbon dioxide, tending to change temperature and rainfall patterns, to which we can easily relate. The science is complex, but it is a simple message for the public to understand. It does not take long to think of several other easily grasped threats, like urban air pollution, poor drinking water, or even the occurrence of horsemeat in food chains. It is perhaps for these reasons that the role of nutrients in environmental change has received much less public attention. After all, nutrients - including nitrogen, phosphorus and many micronutrients - play multiple roles in our world; they affect many biogeochemical processes and they lead to a plethora of interacting threats. If we are not careful, we can quickly get buried in the complexity of the different ways in which our lives are affected by these elements. The outcome is that it can become hard to convey the science of global nutrient cycles in a way that the public can understand. These are points about which we have given substantial thought as we contributed to a recently launched report Our Nutrient World: The challenge to produce more food and energy with less pollution (Sutton et al., 2013). The report was commissioned by the United Nations Environment Programme (UNEP) and conducted by the Global Partnership on Nutrient Management in cooperation with the International Nitrogen Initiative. The commission was not to provide a full scientific assessment, but rather to develop a global overview of the challenges associated with nutrient management. Drawing on existing knowledge, the aim was to distill the nature of the

Water chemistry: protecting the industry's investment. Making or breaking plant operations

International Nuclear Information System (INIS)

Anon.

1983-01-01

Good water chemistry is a good way to preserve the life of steam generators and other plant components. Pipe cracks in boiling-water reactors, tube pitting, denting and cracking in pressurized-water reactors are all problems that are surfacing due to poor water chemistry, i.e., the lack of water purity. Water is essential to power generation and is corrosive under the best of conditions. But to a metal system filled with water and subject to high pressure, high temperature, and impurities such as chlorides, the potential for rapid and permanent damage rises to serious proportions. In addition, radiation levels increase from corrosive products circulated through the reactor vessel

10 years of make-up water treatment with integrated reverse osmosis at Grosskraftwerk Mannheim

International Nuclear Information System (INIS)

Spindler, K.; Bloechl, H.; Bursik, A.

1993-01-01

Since 1982, at Grosskraftwerk Mannheim, a make-up water treatment in which three reverse osmosis plants are integrated, has been operating. The original high-pressure hollow fibre module of these plants has been replaced by low-pressure coil modules. The reasons for the change in system are described in the paper. In the low-pressure plant, coil modules have been installed by several manufacturers. The paper reports on experience with the low-pressure elements. The experience gained has been streamed into the planning proposals for the new make-up water treatment plant. (orig.) [de

Environmental Chemistry and Chemical Ecology of "Green Tide" Seaweed Blooms.

Science.gov (United States)

Van Alstyne, Kathryn L; Nelson, Timothy A; Ridgway, Richard L

2015-09-01

Green tides are large growths or accumulations of green seaweeds that have been increasing in magnitude and frequency around the world. Because green tides consist of vast biomasses of algae in a limited area and are often seasonal or episodic, they go through periods of rapid growth in which they take up large amounts of nutrients and dissolved gases and generate bioactive natural products that may be stored in the plants, released into the environment, or broken down during decomposition. As a result of the use and production of inorganic and organic compounds, the algae in these blooms can have detrimental impacts on other organisms. Here, we review some of the effects that green tides have on the chemistry of seawater and the effects of the natural products that they produce. As blooms are developing and expanding, algae in green tides take up inorganic nutrients, such as nitrate and ortho-phosphate, which can limit their availability to other photosynthetic organisms. Their uptake of dissolved inorganic carbon for use in photosynthesis can cause localized spikes in the pH of seawater during the day with concomitant drops in the pH at night when the algae are respiring. Many of the algae that form green-tide blooms produce allelopathic compounds, which are metabolites that affect other species. The best documented allelopathic compounds include dimethylsulfoniopropionate (DMSP), dopamine, and reactive oxygen species (ROS) and their breakdown products. DMSP and dopamine are involved in defenses against herbivores. Dopamine and ROS are released into seawater where they can be allelopathic or toxic to other organisms. Thus, these macroalgal blooms can have harmful effects on nearby organisms by altering concentrations of nutrients and dissolved gas in seawater and by producing and releasing allelopathic or toxic compounds. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved

BWR water chemistry impurity studies

International Nuclear Information System (INIS)

Ljungberg, L.G.; Korhonen, S.; Renstroem, K.; Hofling, C.G.; Rebensdorff, B.

1990-03-01

Laboratory studies were made on the effect of water impurities on environmental cracking in simulated BWR water of stainless steel, low alloy steel and nickel-base alloys. Constant elongation rate tensile (CERT) tests were run in simulated normal water chemistry (NWC), hydrogen water chemistry (HWC), or start-up environment. Sulfate, chloride and copper with chloride added to the water at levels of a fraction of a ppM were found to be extremely deleterious to all kinds of materials except Type 316 NG. Other detrimental impurities were fluoride, silica and some organic acids, although acetic acid was beneficial. Nitrate and carbon dioxide were fairly inoccuous. Corrosion fatigue and constant load tests on compact tension specimens were run in simulated normal BWR water chemistry (NWC) or hydrogen water chemistry (HWC), without impurities or with added sulfate or carbon dioxide. For sensitized Type 304 SS in NWC, 0.1 ppM sulfate increased crack propagation rates in constant load tests by up to a factor of 100, and in fatigue tests up to a factor of 10. Also, cracking in Type 316 nuclear grade SS and Alloy 600 was enhanced, but to a smaller degree. Carbon dioxide was less detrimental than sulfate. 3 figs., 4 tabs

PWR secondary water chemistry diagnostic system

International Nuclear Information System (INIS)

Miyazaki, S.; Hattori, T.; Yamauchi, S.; Kato, A.; Suganuma, S.; Yoshikawa, T.

1989-01-01

Water chemistry control is one of the most important tasks in order to maintain the reliability of plant equipments and extend operating life of the plant. We developed an advanced water chemistry management system which is able to monitor and diagnose secondary water chemistry. A prototype system had been installed at one plant in Japan since Nov. 1986 in order to evaluate system performance and man-machine interface. The diagnosis system has been successfully tested off line using synthesized plant data for various cases. We are continuing to improve the applicability and develop new technology which make it evaluate steam generator crevice chemistry. (author)

Laboratory studies of stratospheric aerosol chemistry

Science.gov (United States)

Molina, Mario J.

1996-01-01

In this report we summarize the results of the two sets of projects funded by the NASA grant NAG2-632, namely investigations of various thermodynamic and nucleation properties of the aqueous acid system which makes up stratospheric aerosols, and measurements of reaction probabilities directly on ice aerosols with sizes corresponding to those of polar stratospheric cloud particles. The results of these investigations are of importance for the assessment of the potential stratospheric effects of future fleets of supersonic aircraft. In particular, the results permit to better estimate the effects of increased amounts of water vapor and nitric acid (which forms from nitrogen oxides) on polar stratospheric clouds and on the chemistry induced by these clouds.

Development of massively parallel quantum chemistry program SMASH

Energy Technology Data Exchange (ETDEWEB)

Ishimura, Kazuya [Department of Theoretical and Computational Molecular Science, Institute for Molecular Science 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585 (Japan)

2015-12-31

A massively parallel program for quantum chemistry calculations SMASH was released under the Apache License 2.0 in September 2014. The SMASH program is written in the Fortran90/95 language with MPI and OpenMP standards for parallelization. Frequently used routines, such as one- and two-electron integral calculations, are modularized to make program developments simple. The speed-up of the B3LYP energy calculation for (C{sub 150}H{sub 30}){sub 2} with the cc-pVDZ basis set (4500 basis functions) was 50,499 on 98,304 cores of the K computer.

How genes make up your mind

DEFF Research Database (Denmark)

Ramsøy, Thomas; Skov, Martin

2010-01-01

Neuroeconomics is the multidisciplinary study of value-based decision-making. One of the core topics is how emotions affect decision-making. Developments in economic models of decision-making have been influenced by technological innovations and empirical findings in cognitive neuroscience. Now......, a recent approach in cognitive neuroscience, often referred to as "imaging genetics", promises to make significant contributions to our understanding of both behavioral and neural aspects of value-based decision-making. Recent work has demonstrated the role of neurotransmitter alterations in clinical...... states such as Parkinson's disease, depression and anxiety, and how this may affect decision behavior. However, these insights are limited through their focus on extreme neuropathology, which sheds little light on similar functions in healthy individuals. Here, we present and discuss studies of the role...

The Effect of Catchment Urbanization on Nutrient Uptake and Biofilm Enzyme Activity in Lake Superior (USA) Tributary Streams

Science.gov (United States)

We used landscape, habitat, and chemistry variables, along with nutrient spiraling metrics and biofilm extracellular enzyme activity (EEA), to assess the response of streams to the level of urbanization within their catchments. For this study nine streams of similar catchment are...

The role of phosphate conversion coatings in make-up of casing connections

NARCIS (Netherlands)

Ernens, D; van Riet, E.J.; de Rooij, M.B.; Pasaribu, H.R.; van Haaften, W.M.; Schipper, D.J.

2017-01-01

Phosphate conversion coatings are widely used on (premium) casing connections for protection against corrosion. Next to that, in conjunction with the lubricant these coatings provide galling protection. The friction and wear that occurs during make-up and subsequent load cycling determines the

Teaming up

DEFF Research Database (Denmark)

Warhuus, Jan; Günzel-Jensen, Franziska; Robinson, Sarah

2016-01-01

types of team formation: random teacher pre-assigned, student selection, and teacher directed diversity. In each of these modules, ethnographic methods (interviews and observations) were employed. Additionally, we had access to students learning logs, formative and summative assessments, and final exams...... functioning entrepreneurial student teams as most teams lack personal chemistry which makes them anchor their work too much in a pre-defined project. In contrast, we find that students that can form their own teams aim for less diverse teams than what is achieved by random assignment. However, the homophily......Questions we care about (Objectives): When students have to work on challenging tasks, as it is often the case in entrepreneurship classrooms that leverage experiential learning, team success becomes central to the students learning. Yet, the formation of teams is often left up to the students...

Efforts to control radiation build-up in Ringhals

Energy Technology Data Exchange (ETDEWEB)

Egner, K.; Aronsson, P.O.; Erixon, O. [Vattenfall AB, Vaeroebacka (Sweden)

1995-03-01

It is well known that good control of the primary chemistry in a PWR is essential in order to minimize material problems and fuel damages. It has also been well established that the water chemistry has a great influence on accumulation of corrosion products on the fuel and the radiation build-up on primary system surfaces. Ringhals was one of the pioneers to increase operating pH in order to reduce radiation build-up and has now been operating for ten years with pH at 7.4 or (in later years) 7.2. Our experience is favourable and includes low radiation levels in the new (1989) steam generators of Ringhals 2. Ringhals 4 has operated almost its whole life at pH 7.2 or higher and it remains one of the cleanest PWRs of its vintage. In addition to strict adherence to a stable operating chemistry, Ringhals is now working on a program with the aim to find optimum shut-down and start-up chemistry to reduce activity levels in the primary systems. A particular goal is to use the shut-down and start-up chemistry at the 1994 outage in Ringhals 3 in order to reduce doserates in preparation for the planned steam generator replacement in 1995. The paper summarizes the experience to date of the established operating chemistry, on-going tests with modified shut-down and start-up chemistry and other measures to limit or reduce the activity build-up.

Efforts to control radiation build-up in Ringhals

International Nuclear Information System (INIS)

Egner, K.; Aronsson, P.O.; Erixon, O.

1995-01-01

It is well known that good control of the primary chemistry in a PWR is essential in order to minimize material problems and fuel damages. It has also been well established that the water chemistry has a great influence on accumulation of corrosion products on the fuel and the radiation build-up on primary system surfaces. Ringhals was one of the pioneers to increase operating pH in order to reduce radiation build-up and has now been operating for ten years with pH at 7.4 or (in later years) 7.2. Our experience is favourable and includes low radiation levels in the new (1989) steam generators of Ringhals 2. Ringhals 4 has operated almost its whole life at pH 7.2 or higher and it remains one of the cleanest PWRs of its vintage. In addition to strict adherence to a stable operating chemistry, Ringhals is now working on a program with the aim to find optimum shut-down and start-up chemistry to reduce activity levels in the primary systems. A particular goal is to use the shut-down and start-up chemistry at the 1994 outage in Ringhals 3 in order to reduce doserates in preparation for the planned steam generator replacement in 1995. The paper summarizes the experience to date of the established operating chemistry, on-going tests with modified shut-down and start-up chemistry and other measures to limit or reduce the activity build-up

Inorganic nutrients, sulfide and oxygen profiles from R/V KNORR in the Black Sea from 19880514 to 19880725 (NODC Accession 9400101)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data collection contains inorganic nutrient chemistry, sulfide and oxygen data collected during cruises 2 through 5 of the 1988 Black Sea Oceanographic...

A spatial and seasonal assessment of river water chemistry across North West England.

Science.gov (United States)

Rothwell, J J; Dise, N B; Taylor, K G; Allott, T E H; Scholefield, P; Davies, H; Neal, C

2010-01-15

This paper presents information on the spatial and seasonal patterns of river water chemistry at approximately 800 sites in North West England based on data from the Environment Agency regional monitoring programme. Within a GIS framework, the linkages between average water chemistry (pH, sulphate, base cations, nutrients and metals) catchment characteristics (topography, land cover, soil hydrology, base flow index and geology), rainfall, deposition chemistry and geo-spatial information on discharge consents (point sources) are examined. Water quality maps reveal that there is a clear distinction between the uplands and lowlands. Upland waters are acidic and have low concentrations of base cations, explained by background geological sources and land cover. Localised high concentrations of metals occur in areas of the Cumbrian Fells which are subjected to mining effluent inputs. Nutrient concentrations are low in the uplands with the exception sites receiving effluent inputs from rural point sources. In the lowlands, both past and present human activities have a major impact on river water chemistry, especially in the urban and industrial heartlands of Greater Manchester, south Lancashire and Merseyside. Over 40% of the sites have average orthophosphate concentrations >0.1mg-Pl(-1). Results suggest that the dominant control on orthophosphate concentrations is point source contributions from sewage effluent inputs. Diffuse agricultural sources are also important, although this influence is masked by the impact of point sources. Average nitrate concentrations are linked to the coverage of arable land, although sewage effluent inputs have a significant effect on nitrate concentrations. Metal concentrations in the lowlands are linked to diffuse and point sources. The study demonstrates that point sources, as well as diffuse sources, need to be considered when targeting measures for the effective reduction in river nutrient concentrations. This issue is clearly important

Learning affects top down and bottom up modulation of eye movements in decision making

DEFF Research Database (Denmark)

Orquin, Jacob Lund; Bagger, Martin; Mueller Loose, Simone

2013-01-01

Repeated decision making is subject to changes over time such as decreases in decision time and information use and increases in decision accuracy. We show that a traditional strategy selection view of decision making cannot account for these temporal dynamics without relaxing main assumptions...... about what defines a decision strategy. As an alternative view we suggest that temporal dynamics in decision making are driven by attentional and perceptual processes and that this view has been expressed in the information reduction hypothesis. We test the information reduction hypothesis by integrating...... it in a broader framework of top down and bottom up processes and derive the predictions that repeated decisions increase top down control of attention capture which in turn leads to a reduction in bottom up attention capture. To test our hypotheses we conducted a repeated discrete choice experiment with three...

Some aspects of the chemistry of fast reactor fuel, structural material and decontamination

International Nuclear Information System (INIS)

Ganesan, V.

2012-01-01

The chemistry of materials pertaining to fast reactors is both fascinating and challenging considering the nature of materials involved such as the fuel, coolant, control and shielding materials in addition to the interactions between the structural materials and the fuel/coolant depending on the nature and conditions involved. The different chemical forms of fuel materials, the need to operate up to high burnups with consequent interactions of the fuel with clad materials, the need to close the fuel cycle by recovery of the fuel materials from spent fuels for refabrication and the necessity to manage the waste, throw a host of challenges which make their study scientifically interesting and technologically important. The use of liquid sodium as coolant in fast reactor heat transport systems combined with its inherent chemical reactivity opens up an interesting branch of chemistry involving liquid sodium especially in contact with structural materials during normal operation of the reactor and with fuels in the event of fuel pin failure. The phenomenon of sodium wetting and the associated corrosion of structural materials in contact with it combined with the need to carryout decontamination of such materials make it interesting to examine and evaluate their suitability for reuse without compromising on their structural integrity. Boron being the material of choice for control and shielding applications in fast reactors with varying isotopic enrichment and the technological challenge to produce large quantities of boron carbide makes it unique. Some of these aspects are addressed in this paper. (author)

TEXTBOOK ANALYSIS IN THE SERVICE OF CHEMISTRY TEACHING

Directory of Open Access Journals (Sweden)

Aija Ahtineva

2005-06-01

Full Text Available The authors of textbooks have their own visions of contents and teaching methods, which should lead to a high level of scientific thinking. However, the textbook alone does not guarantee good results because the personal and social relationships between the teacher and students have a major influence on teaching and learning. Therefore, the teacher’s study of the textbook before teaching facilitates the teaching process. This paper suggests one method of textbook analysis. In the analysis, one upper secondary level course of chemistry instruction involved the use of a learning strategy: classification of the central concepts and a classification of activities based on task difficulty. The study also attempted to find out the goodness of fit between the national curriculum and the textbook chemistry course. The national objectives concerned the content of knowledge, social significance, emphasis on experimental chemistry, and inspiring students for further study. The majority of the textbook tasks fall into higher order categories characterized by knowledge structures assuming application of knowledge or making inferences. Good textbook activities also have social significance, and a number of experimental tasks are included. The textbook quality is further enhanced by up-to-date content. All of the above qualities are related to high study motivation.

Mariculture: significant and expanding cause of coastal nutrient enrichment

International Nuclear Information System (INIS)

Bouwman, Lex; Beusen, Arthur; Glibert, Patricia M; Overbeek, Ciska; Pawlowski, Marcin; Herrera, Jorge; Mulsow, Sandor; Yu, Rencheng; Zhou, Mingjiang

2013-01-01

Mariculture (marine aquaculture) generates nutrient waste either through the excretion by the reared organisms, or through direct enrichment by, or remineralization of, externally applied feed inputs. Importantly, the waste from fish or shellfish cannot easily be managed, as most is in dissolved form and released directly to the aquatic environment. The release of dissolved and particulate nutrients by intensive mariculture results in increasing nutrient loads (finfish and crustaceans), and changes in nutrient stoichiometry (all mariculture types). Based on different scenarios, we project that nutrients from mariculture will increase up to six fold by 2050 with exceedance of the nutrient assimilative capacity in parts of the world where mariculture growth is already rapid. Increasing nutrient loads and altered nutrient forms (increased availability of reduced relative to oxidized forms of nitrogen) and/or stoichiometric proportions (altered nitrogen:phosphorus ratios) may promote an increase in harmful algal blooms (HABs) either directly or via stimulation of algae on which mixotrophic HABs may feed. HABs can kill or intoxicate the mariculture product with severe economic losses, and can increase risks to human health. (letter)

A green chemistry lab course

International Nuclear Information System (INIS)

Rank, J.; Lenoir, D.; Bahadir, M.; Koning, B.

2006-01-01

The traditional course content of chemistry classes must change to achieve better awareness of the important issues of sustainability in chemistry within the next generation of professional chemists. To provide the necessary material for the organic chemistry teaching lab course, which is part of almost all study programs in chemistry, material was developed and collected (http://www.oc-praktikum.de/en) that allows students and teachers to assess reactions beyond the experimental set up, reaction mechanism and chemical yield. Additional parameters like atom economy of chemical transformations, energy efficiency, and questions of waste, renewable feed stocks, toxicity and ecotoxicity, as well as the safety measures for the chemicals used are discussed. (author)

Inorganic chemistry and medicine

International Nuclear Information System (INIS)

Sadler, P.J.; Guo, Z.

1999-01-01

Inorganic chemistry is beginning to have a major impact on medicine. Not only does it offer the prospect of the discovery of truly novel drugs and diagnostic agents, but it promises to make a major contribution to our understanding of the mechanism of action of organic drugs too. Most of this article is concerned with recent developments in medicinal coordination chemistry. The role of metal organic compounds of platinum, titanium, ruthenium, gallium, bismuth, gold, gadolinium, technetium, silver, cobalt in the treatment or diagnosis of common diseases are briefly are examined

A Studio Based Approach to Enhancing Decision Making in Sme Start-Up

NARCIS (Netherlands)

Sol, H G; Ejiri, A.H.; Nabukenya, J.

2011-01-01

The start-up phase plays an important role in the success and survival of many enterprises, which greatly depends on adequate and timely services for decision making. However, deciding to startup a mining Small and Medium Enterprise (SME) is a challenging task for many entrepreneurs in Uganda.

Reliability study: raw and make-up water system, Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Peterman, S.M.; Wiehle, W.E.; Walder, A.; Houk, T.C.; West, R.M.

1981-09-01

A reliability study for determining the ability of the raw and make-up water system to provide reliable and adequate service through the year 2000 has been completed. This study includes an evaluation of the well fields, X-608 Raw Water Pump House, X-605 Booster Station Complex, X-611 Water Treatment Complex, and the associated piping. The raw and make-up water system is in good overall condition, but to maintain this condition, the reliability study team made the following recommendations: (1) increase well field capacity; (2) replace certain speed reducers at X-611; (3) repair deteriorated poles, crossarms, and accessories on F-2 and W-1 feeders; (4) stabilize the landslide in vicinity of the 48 in. raw water main; and (5) initiate further investigation, testing, or engineering studies to correct deficiencies in the supervisory control system between well fields, pump house, and X-611, and determine if the 2400 volt underground cables to X-608A wells should be replaced

Quantum Chemistry; A concise introduction for students of physics, chemistry, biochemistry and materials science

Science.gov (United States)

Thakkar, Ajit J.

2017-09-01

This book provides non-specialists with a basic understanding of the underlying concepts of quantum chemistry. It is both a text for second- or third-year undergraduates and a reference for researchers who need a quick introduction or refresher. All chemists and many biochemists, materials scientists, engineers, and physicists routinely use spectroscopic measurements and electronic structure computations in their work. The emphasis of Quantum Chemistry on explaining ideas rather than enumerating facts or presenting procedural details makes this an excellent foundation text/reference.

Dynamic vertical profiles of peat porewater chemistry in a northern peatland

Science.gov (United States)

Natalie A. Griffiths; Stephen D. Sebestyen

2016-01-01

We measured pH, cations, nutrients, and total organic carbon (TOC) over 3 years to examine weekly to monthly variability in porewater chemistry depth profiles (0–3.0 m) in an ombrotrophic bog in Minnesota, USA. We also compared temporal variation at one location to spatial variation in depth profiles at 16 locations across the bog. Most solutes exhibited large...

Covalent electron transfer chemistry of graphene with diazonium salts.

Science.gov (United States)

Paulus, Geraldine L C; Wang, Qing Hua; Strano, Michael S

2013-01-15

Graphene is an atomically thin, two-dimensional allotrope of carbon with exceptionally high carrier mobilities, thermal conductivity, and mechanical strength. From a chemist's perspective, graphene can be regarded as a large polycyclic aromatic molecule and as a surface without a bulk contribution. Consequently, chemistries typically performed on organic molecules and surfaces have been used as starting points for the chemical functionalization of graphene. The motivations for chemical modification of graphene include changing its doping level, opening an electronic band gap, charge storage, chemical and biological sensing, making new composite materials, and the scale-up of solution-processable graphene. In this Account, we focus on graphene functionalization via electron transfer chemistries, in particular via reactions with aryl diazonium salts. Because electron transfer chemistries depend on the Fermi energy of graphene and the density of states of the reagents, the resulting reaction rate depends on the number of graphene layers, edge states, defects, atomic structure, and the electrostatic environment. We limit our Account to focus on pristine graphene over graphene oxide, because free electrons in the latter are already bound to oxygen-containing functionalities and the resulting chemistries are dominated by localized reactivity and defects. We describe the reaction mechanism of diazonium functionalization of graphene and show that the reaction conditions determine the relative degrees of chemisorption and physisorption, which allows for controlled modulation of the electronic properties of graphene. Finally we discuss different applications for graphene modified by this chemistry, including as an additive in polymer matrices, as biosensors when coupled with cells and biomolecules, and as catalysts when combined with nanoparticles.

Chemistry of groundwater discharge inferred from longitudinal river sampling

Science.gov (United States)

Batlle-Aguilar, J.; Harrington, G. A.; Leblanc, M.; Welch, C.; Cook, P. G.

2014-02-01

We present an approach for identifying groundwater discharge chemistry and quantifying spatially distributed groundwater discharge into rivers based on longitudinal synoptic sampling and flow gauging of a river. The method is demonstrated using a 450 km reach of a tropical river in Australia. Results obtained from sampling for environmental tracers, major ions, and selected trace element chemistry were used to calibrate a steady state one-dimensional advective transport model of tracer distribution along the river. The model closely reproduced river discharge and environmental tracer and chemistry composition along the study length. It provided a detailed longitudinal profile of groundwater inflow chemistry and discharge rates, revealing that regional fractured mudstones in the central part of the catchment contributed up to 40% of all groundwater discharge. Detailed analysis of model calibration errors and modeled/measured groundwater ion ratios elucidated that groundwater discharging in the top of the catchment is a mixture of local groundwater and bank storage return flow, making the method potentially useful to differentiate between local and regional sourced groundwater discharge. As the error in tracer concentration induced by a flow event applies equally to any conservative tracer, we show that major ion ratios can still be resolved with minimal error when river samples are collected during transient flow conditions. The ability of the method to infer groundwater inflow chemistry from longitudinal river sampling is particularly attractive in remote areas where access to groundwater is limited or not possible, and for identification of actual fluxes of salts and/or specific contaminant sources.

Maintenance, outages and chemistry really can be compatible

International Nuclear Information System (INIS)

Roberts, J.G.; Deaconescu, R.

2006-01-01

'Full text:' In their address to the Canadian Nuclear Society, Bruce Power's Chemistry Design staff will describe how maintenance and outages can impact negatively on chemistry control and asset protection. Considerations of material impacts and material condition have significant influences on the approach to, and control of, chemistry. This applies equally to operation as it does during unit and/or system outages. Ideas will be presented as to how to facilitate making maintenance, outages and chemistry compatible. It will be shown how the lack of such an approach can lead to disastrous results. (author)

Standardisation of an European end-user nutrient database for nutritional epidemiology: what can we learn from the EPIC Nutrient Database (ENDB) project?

DEFF Research Database (Denmark)

Slimani, N.; Deharveng, G.; Unwin, I.

2007-01-01

the absence of a reference European nutrient database for international nutritional epidemiology studies, the EPIC Nutrient Database (ENDB) project has been set up to standardise nutrient databases (NDBs) across 10 European countries participating in the EPIC study. This paper reports the main...... problems in harmonising NDBs experienced by end-user in the ENDB project and the solutions adopted to prevent and minimize them, which are also relevant for other large European nutritional studies. Furthermore, it provides end-user recommendations for improving the comparability of European and other NDBs...

Make up your mind - How stress and sex affect decision-making

NARCIS (Netherlands)

Koot, S.

2013-01-01

Decision-making refers to assessing costs and benefits of competing actions, with either a known outcome or an uncertain result. Decision-making depends on several abilities, such as behavioural flexibility and inhibiting risky responses. Several factors affect decision-making, causing differences

Computerized system of team make-up and work allocation in the Belgian Zolder mine

Energy Technology Data Exchange (ETDEWEB)

Rustanowicz, M.

1979-01-01

System of work allocation introduced in 1974 in the Zolder Coal Mine (NV Kempense Steenkolenmijnen) in Belgium is evaluated. The system is based on an IBM 370/158 computer. An information management system supervises the programing work. There are approximately 30 programs. Absenteeism in the Belgian coal mines is generally high at approximately 24% and some months as high as 40%. Therefore, introducing a computerized system of work allocation and team make-up was advantageous. Operation of the system is described on the levels of foreman, engineers and director of the mine. Advantages of the system are numerous. It enables optimization of team make-up and work allocation, shortens the time of allocation of work by a foreman, increases efficiency of foremen's work and provides the director with the means and information necessary for efficient decision making in improving the productivity of the mine. (5 refs.) (In Polish)

Analysis of hide-out return and the composition of the steam generators' combined blowdown under ethanolamine chemistry

International Nuclear Information System (INIS)

Rodriguez Aliciardi, M; Belloni, M; Croatto, F; Ferrari, F; Herrera, C; Mendizabal, M; Montes, J; Saucedo, R; Rodriguez, I; Chocron, M

2012-01-01

Among the techniques recommended for the surveillance of the steam generators (SG's) are (i) the follow-up of the corrosion products in the feed water and blown-down water and the corresponding accumulation mass balance and (ii) the follow-up of the ionic impurities normally present in the main condensate and feed water that can enter in the cycle either through condenser leakages or even with the make-up water. This is, no matter how well the cycle is constructed or the make-up water plant behaves, given the continuous phase change present in the cycle, a concentration equilibrium is established. Moreover, a synergistic effect exists between both, corrosion products and impurities, (i) and (ii), because impurities concentrate in crevices and deposits creating a potentially corrosion risky environment for the SG's tubes. Hide-out return determination consists in the measurement of ions' concentrations, present in the blown-down water which are eluted in the shutdown during the power and temperature reduction. The integrated values allow graphical representations for performing several evaluations like: (i) the performance make-up water plant during a period, (ii) the presence of condenser in-leakages, (iii) the SG's deposits estimation and (iv) the internal chemistry of the SG's liquid phase inside the sludge pile. CNE, a CANDU 6 pressurized heavy-water reactor (PHWR) located in Embalse, Cordoba Province, Argentina, is close to reach the end-of-design-life and a life extension project is currently ongoing. In the plant also the chemistry of the BOP has been modified from a morpholine to an ethanolamine chemistry (Fernandez et. al, NPC'2010, October 3-7, Quebec City, Canada) to enhance protection of SG's internals and new SG's will be installed. Then, it is of interest to set up a hide-out return procedure and analysis of the combined blown-down crud collected during the shut down as a base line for the second period of

Effects of Fallow Genealogical Cycles on the Build-up of Nutrients in ...

African Journals Online (AJOL)

The study examined the effect of fallow generational cycles on the buildup of nutrients in the soil. Fallow sequence of 1st, 2nd, 3rd, 4th and 5th generations were studied. The quadrat approach of sampling was employed to collect soil samples (surface and subsurface) from five plots of 10m x 10m across the five fallow ...

Chemistry control challenges in a supercritical water-cooled reactor

International Nuclear Information System (INIS)

Guzonas, David; Tremaine, Peter; Jay-Gerin, Jean-Paul

2009-01-01

The long-term viability of a supercritical water-cooled reactor (SCWR) will depend on the ability of designers to predict and control water chemistry to minimize corrosion and the transport of corrosion products and radionuclides. Meeting this goal requires an enhanced understanding of water chemistry as the temperature and pressure are raised beyond the critical point. A key aspect of SCWR water chemistry control will be mitigation of the effects of water radiolysis; preliminary studies suggest markedly different behavior than that predicted from simple extrapolations from conventional water-cooled reactor behavior. The commonly used strategy of adding excess hydrogen at concentrations sufficient to suppress the net radiolytic production of primary oxidizing species may not be effective in an SCWR. The behavior of low concentrations of impurities such as transition metal corrosion products, chemistry control agents, anions introduced via make-up water or from ion-exchange resins, and radionuclides (e.g., 60 Co) needs to be understood. The formation of neutral complexes increases with temperature, and can become important under near-critical and supercritical conditions; the most important region is from 300-450 C, where the properties of water change dramatically, and solvent compressibility effects exert a huge influence on solvation. The potential for increased transport and deposition of corrosion products (active and inactive), leading to (a) increased deposition on fuel cladding surfaces, and (b) increased out-of-core radiation fields and worker dose, must be assessed. There are also significant challenges associated with chemistry sampling and monitoring in an SCWR. The typical methods used in current reactor designs (grab samples, on-line monitors at the end of a cooled, depressurized sample line) will be inadequate, and in-situ measurements of key parameters will be required. This paper describes current Canadian activities in SCWR chemistry and chemistry

Smart Cities Will Need Chemistry

Directory of Open Access Journals (Sweden)

Alexandru WOINAROSCHY

2016-06-01

Full Text Available A smart city is a sustainable and efficient urban centre that provides a high quality of life to its inhabitants through optimal management of its resources. Chemical industry has a key role to play in the sustainable evolution of the smart cities. Additionally, chemistry is at the heart of all modern industries, including electronics, information technology, biotechnology and nano-technology. Chemistry can make the smart cities project more sustainable, more energy efficient and more cost effective. There are six broad critical elements of any smart city: water management systems; infrastructure; transportation; energy; waste management and raw materials consumption. In all these elements chemistry and chemical engineering are deeply involved.

Macro- and micro-nutrient concentration in leaf, woody, and root tissue of Populus irrigated with landfill leachate

Science.gov (United States)

Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Bart T. Sexton; Richard B. Hall

2007-01-01

Landfill leachate offers an opportunity to supply water and plant nutritional benefits at a lower cost than traditional sources. Information about nutrient uptake and distribution into tissues of Populus irrigated with landfill leachate helps increase biomass production along with evaluating the impacts of leachate chemistry on tree health.

Antiparallel Dynamic Covalent Chemistries

NARCIS (Netherlands)

Matysiak, Bartosz M.; Nowak, Piotr; Cvrtila, Ivica; Pappas, Charalampos G.; Liu, Bin; Komaromy, David; Otto, Sijbren

2017-01-01

The ability to design reaction networks with high, but addressable complexity is a necessary prerequisite to make advanced functional chemical systems. Dynamic combinatorial chemistry has, proven to be a useful tool in achieving complexity, however with some limitations in controlling it. Herein we

Editorial: Nanoscience makes catalysis greener

KAUST Repository

Polshettiwar, Vivek

2012-01-09

Green chemistry by nanocatalysis: Catalysis is a strategic field of science because it involves new ways of meeting energy and sustainability challenges. The concept of green chemistry, which makes the science of catalysis even more creative, has become an integral part of sustainability. This special issue is at the interface of green chemistry and nanocatalysis, and features excellent background articles as well as the latest research results. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Groundwater – The disregarded component in lake water and nutrient budgets. Part 2: effects of groundwater on nutrients

Science.gov (United States)

Lewandowski, Jörg; Meinikmann, Karin; Nützmann, Gunnar; Rosenberry, Donald O.

2015-01-01

Lacustrine groundwater discharge (LGD) transports nutrients from a catchment to a lake, which may fuel eutrophication, one of the major threats to our fresh waters. Unfortunately, LGD has often been disregarded in lake nutrient studies. Most measurement techniques are based on separate determinations of volume and nutrient concentration of LGD: Loads are calculated by multiplying seepage volumes by concentrations of exfiltrating water. Typically low phosphorus (P) concentrations of pristine groundwater often are increased due to anthropogenic sources such as fertilizer, manure or sewage. Mineralization of naturally present organic matter might also increase groundwater P. Reducing redox conditions favour P transport through the aquifer to the reactive aquifer-lake interface. In some cases, large decreases of P concentrations may occur at the interface, for example, due to increased oxygen availability, while in other cases, there is nearly no decrease in P. The high reactivity of the interface complicates quantification of groundwater-borne P loads to the lake, making difficult clear differentiation of internal and external P loads to surface water. Anthropogenic sources of nitrogen (N) in groundwater are similar to those of phosphate. However, the environmental fate of N differs fundamentally from P because N occurs in several different redox states, each with different mobility. While nitrate behaves essentially conservatively in most oxic aquifers, ammonium's mobility is similar to that of phosphate. Nitrate may be transformed to gaseous N2 in reducing conditions and permanently removed from the system. Biogeochemical turnover of N is common at the reactive aquifer-lake interface. Nutrient loads from LGD were compiled from the literature. Groundwater-borne P loads vary from 0.74 to 2900 mg PO4-P m−2 year−1; for N, these loads vary from 0.001 to 640 g m−2 year−1. Even small amounts of seepage can carry large nutrient loads due to often high

Farmer Field School on Nutrient Management.

NARCIS (Netherlands)

Onduru, D.; Muchena, F.N.; Gachimbi, L.N.; Jager, de A.

2003-01-01

In Kenya Integrated Nutrient Management (INM) is being used to make the best use of local resources and to optimise the effects of external inputs. In Mbeere, a district that lies in the dryland area of Eastern Kenya the Farmer Field School (FFS) has been in operation during one season and work is

Designing the Next-Generation Chemistry Journal: The Internet Journal of Chemistry.

Science.gov (United States)

Bachrach, Steven M.; Burleigh, Darin C.; Krassivine, Anatoli

1998-01-01

Discusses how the journal "Internet Journal of Chemistry" is designed to take advantage of newly available technologies. Describes the development of the concept of an electronic journal, decision-making on the scope and coverage of the journal, financial logistics, and how the journal will be implemented. Includes perspectives on how this new…

Water chemistry experiences with VVERs at Kudankulam

International Nuclear Information System (INIS)

Rout, D.; Upadhyaya, T.C.; Ravindranath; Selvinayagam, P.; Sundar, R.S.

2015-01-01

Kudankulam Nuclear Power Project - 1 and 2 (Kudankulam NPP - 1 and 2) are pressurised water cooled VVERs of 1000 MWe each. Kudankulam NPP Unit - 1 is presently on its first cycle of operation and Kudankulam NPP Unit - 2 is on the advanced stage of commissioning with the successful completion of hot run related Functional tests. Water Chemistry aspects during various phases of commissioning of Kudankulam NPP Unit - 1 such as Hot Run, Boric acid flushing, initial fuel Loading (IFL), First approach to Criticality (FAC) are discussed. The main objectives of the use of controlled primary water chemistry programme during the hot functional tests are reviewed. The importance of the relevant water chemistry parameters were ensured to have the quality of the passive layer formed on the primary coolant system surfaces. The operational experiences during the 1 st cycle of operation of primary water chemistry, radioactivity transport and build-up are presented. The operational experience of some VVER units in the field of the primary water chemistry, radioactivity transport and build-up are presented as a comparison to VVER at Kudankulam NPP. The effects of the initial passivated layer formed on metal surfaces during hot run, activated corrosion products levels in the primary coolant under controlled water chemistry regime and the contamination/radiation situation are discussed. This report also includes the water chemistry related issues of secondary water systems. (author)

Research for the advancement of green chemistry practice: Studies in atmospheric and educational chemistry

Science.gov (United States)

Cullipher, Steven Gene

Green chemistry is a philosophy of chemistry that emphasizes a decreasing dependence on limited non-renewable resources and an increasing focus on preventing pollution byproducts of the chemical industry. In short, it is the discipline of chemistry practiced through the lens of environmental stewardship. In an effort to advance the practice of green chemistry, three studies will be described that have ramifications for the practice. The first study examines the atmospheric oxidation of a hydrofluorinated ether, a third-generation CFC replacement compound with primarily unknown atmospheric degradation products. Determination of these products has the potential to impact decisions on refrigerant usage in the future. The second study examines chemistry students' development of understanding benefits-costs-risks analysis when presented with two real-world scenarios: refrigerant choice and fuel choice. By studying how benefits-costs-risks thinking develops, curricular materials and instructional approaches can be designed to better foster the development of an ability that is both necessary for green chemists and important in daily decision-making for non-chemists. The final study uses eye tracking technology to examine students' abilities to interpret molecular properties from structural information in the context of global warming. Such abilities are fundamental if chemists are to appropriately assess risks and hazards of chemistry practice.

Reeds as indicators of nutrient enrichment in a small temporarily ...

African Journals Online (AJOL)

Nutrient (NH4 and SRP) concentrations decreased from the bank towards the main estuary channel, suggesting that nutrients introduced into the estuary in groundwater and surface runoff were taken up by the fringe of reeds. The roots, rhizomes, stems and leaves of Phragmites at the site with the greatest Phragmites ...

Nutrients in the nexus

Science.gov (United States)

Davidson, Eric A.; Niphong, Rachel; Ferguson, Richard B.; Palm, Cheryl; Osmond, Deanna L.; Baron, Jill S.

2016-01-01

Synthetic nitrogen (N) fertilizer has enabled modern agriculture to greatly improve human nutrition during the twentieth century, but it has also created unintended human health and environmental pollution challenges for the twenty-first century. Averaged globally, about half of the fertilizer-N applied to farms is removed with the crops, while the other half remains in the soil or is lost from farmers’ fields, resulting in water and air pollution. As human population continues to grow and food security improves in the developing world, the dual development goals of producing more nutritious food with low pollution will require both technological and socio-economic innovations in agriculture. Two case studies presented here, one in sub-Saharan Africa and the other in Midwestern United States, demonstrate how management of nutrients, water, and energy is inextricably linked in both small-scale and large-scale food production, and that science-based solutions to improve the efficiency of nutrient use can optimize food production while minimizing pollution. To achieve the needed large increases in nutrient use efficiency, however, technological developments must be accompanied by policies that recognize the complex economic and social factors affecting farmer decision-making and national policy priorities. Farmers need access to affordable nutrient supplies and support information, and the costs of improving efficiencies and avoiding pollution may need to be shared by society through innovative policies. Success will require interdisciplinary partnerships across public and private sectors, including farmers, private sector crop advisors, commodity supply chains, government agencies, university research and extension, and consumers.

Improvements in recall and food choices using a graphical method to deliver information of select nutrients.

Science.gov (United States)

Pratt, Nathan S; Ellison, Brenna D; Benjamin, Aaron S; Nakamura, Manabu T

2016-01-01

Consumers have difficulty using nutrition information. We hypothesized that graphically delivering information of select nutrients relative to a target would allow individuals to process information in time-constrained settings more effectively than numerical information. Objectives of the study were to determine the efficacy of the graphical method in (1) improving memory of nutrient information and (2) improving consumer purchasing behavior in a restaurant. Values of fiber and protein per calorie were 2-dimensionally plotted alongside a target box. First, a randomized cued recall experiment was conducted (n=63). Recall accuracy of nutrition information improved by up to 43% when shown graphically instead of numerically. Second, the impact of graphical nutrition signposting on diner choices was tested in a cafeteria. Saturated fat and sodium information was also presented using color coding. Nutrient content of meals (n=362) was compared between 3 signposting phases: graphical, nutrition facts panels (NFP), or no nutrition label. Graphical signposting improved nutrient content of purchases in the intended direction, whereas NFP had no effect compared with the baseline. Calories ordered from total meals, entrées, and sides were significantly less during graphical signposting than no-label and NFP periods. For total meal and entrées, protein per calorie purchased was significantly higher and saturated fat significantly lower during graphical signposting than the other phases. Graphical signposting remained a predictor of calories and protein per calorie purchased in regression modeling. These findings demonstrate that graphically presenting nutrition information makes that information more available for decision making and influences behavior change in a realistic setting. Copyright © 2016 Elsevier Inc. All rights reserved.

Catch-Up: A Rule That Makes Service Sports More Competitive

OpenAIRE

Brams, Steven J.; Ismail, Mehmet S.; Kilgour, D. Marc; Stromquist, Walter

2016-01-01

Service sports include two-player contests such as volleyball, badminton, and squash. We analyze four rules, including the Standard Rule (SR), in which a player continues to serve until he or she loses. The Catch-Up Rule (CR) gives the serve to the player who has lost the previous point—as opposed to the player who won the previous point, as under SR. We also consider two Trailing Rules that make the server the player who trails in total score. Surprisingly, compared with SR, only CR gives th...

Catch-Up:A Rule that Makes Service Sports More Competitive

OpenAIRE

Brams, Steven; Ismail, Mehmet; Kilgour, Marc; Stromquist, Walter

2018-01-01

Service sports include two-player contests such as volleyball, badminton, and squash. We analyze four rules, including the Standard Rule (SR), in which a player continues to serve until he or she loses. The Catch-Up Rule (CR) gives the serve to the player who has lost the previous point—as opposed to the player who won the previous point, as under SR. We also consider two Trailing Rules that make the server the player who trails in total score. Surprisingly, compared with SR, only CR gives th...

Maintenance, outages and chemistry really can be compatible

Energy Technology Data Exchange (ETDEWEB)

Roberts, J.G.; Deaconescu, R. [Bruce Power, Tiverton, Ontario (Canada)

2006-07-01

'Full text:' In their address to the Canadian Nuclear Society, Bruce Power's Chemistry Design staff will describe how maintenance and outages can impact negatively on chemistry control and asset protection. Considerations of material impacts and material condition have significant influences on the approach to, and control of, chemistry. This applies equally to operation as it does during unit and/or system outages. Ideas will be presented as to how to facilitate making maintenance, outages and chemistry compatible. It will be shown how the lack of such an approach can lead to disastrous results. (author)

Soil chemistry and nutrition of North American spruce-fir stands: Evidence of recent change

International Nuclear Information System (INIS)

Joslin, J.D.; Kelly, J.M.; Van Miegroet, H.

1992-01-01

One set of hypotheses offered to explain the decline of red spruce (Picea rubens Sarg.) in eastern North America focuses on the effect of acidic deposition on soil chemistry changes that may affect nutrient availability and root function. Long-term soils data suggests that soil acidification has occurred in some spruce stands over the past 50 yr, with plant uptake and cation leaching both contributing to the loss of cations. Studies of tree ring chemistry also have indicated changes in Ca/Al and Mg/Al ratios in red spruce wood, suggesting increases in the ionic strength of soil solution. Irrigation studies using strong acid inputs have demonstrated accelerated displacement of base cations from upper horizons. Spruce-fir (Abies spp.) nutrient budgets indicate that current net Ca and Mg leaching loss rates are of the same order of magnitude as losses to whole tree harvest removals, spread out over a 50-yr rotation. For most cations, red spruce foliar nutrient levels decline with elevation, but it is difficult to assess the contribution of the elevational gradient in atmospheric deposition to this pattern. Compared to northeastern sites, spruce-fir soil solutions in the southern Appalachians have higher nitrate levels and higher Al concentrations, which at times approach the Al toxicity threshold for red spruce seedlings and frequently are at levels known to interfere with cation uptake. There is little evidence that either nutrient deficiencies or Al toxicity are primary causes of red spruce decline in the Northeast, though both may play a role in the Southeast

Molecular and risk-based approach to nutrient development for a proposed sub-surface biogasification field trial in a biogenic gas field

Energy Technology Data Exchange (ETDEWEB)

Lambo, Adewale J.; Strapoc, Dariusz; Pittenger, Michelle; Huizinga, Bradley [ConocoPhillips (Canada); Wood, Ladonna; Ashby, Matt [Taxon Biosciences (Canada)

2011-07-01

This paper presents the molecular and risk-based approach to nutrient development for a proposed sub-surface biogasification field trial in a biogenic gas field. From field sampling, variability was seen in water chemistry and environmental parameters across the field; DNA yield also varied across the field and showed distinct spatial variation. The composition of microbial populations and relative distribution of archaea populations in the Cooks Inlet water is represented using pie and bar charts. The nutrient recipe was developed using known information on nutrient requirements of mathematically correlated microbial associations. The process of on-site nutrient injection is explained. Some of the mitigation plans for the risks involved during the process include, among others, limiting biofilm prevalence and avoiding bio-plugging and bio-corrosion. Biofilm is likely to develop in the injection line but less likely in nutrient mixing due to the high nutrient concentration. From the study, it can be concluded that community composition correlates with field geochemical parameters and methane pathways.

Towards regional mapping of grass nutrients using remote sensing in Greater Kruger National Park

CSIR Research Space (South Africa)

Ramoelo, Abel

2011-03-01

Full Text Available Regional maps of grass nutrients are important to inform decision making regarding the management of savanna ecosystems. Grass nutrients plays a crucial role in understanding the distribution, densities and feeding patterns of both wild herbivores...

21 CFR 101.13 - Nutrient content claims-general principles.

Science.gov (United States)

2010-04-01

... from recognized data bases for raw and processed foods, recipes, and other means to compute nutrient... and amounts of ingredients, cooking temperatures, etc.). Firms making claims on foods based on this...

Etymology as an Aid to Understanding Chemistry Concepts

Science.gov (United States)

Sarma, Nittala S.

2004-01-01

Learning the connection between the roots and the chemical meaning of terms can improve students' understanding of chemistry concepts, making them easier and more enjoyable to master. The way in which using etymology to understand the meanings and relationships of chemistry terms can aid students in strengthening and expanding their grasp of…

Another Look at the Chimera of Cookbook Chemistry

Science.gov (United States)

Feifer, Nathan

1969-01-01

Argues that the traditional chemistry laboratory manual is not inherently a cookbook and the modern course manual does not automatically eliminate the cookbook approach. Suggests that it is the nature of the teacher guidance that students receive before, after, and during the laboratory work that makes a chemistry program meaningful and effective.…

Water chemistry control at FBTR

International Nuclear Information System (INIS)

Panigrahi, B.S.; Jambunathan, D.; Suresh Kumar, K.V.; Ramanathan, V.; Srinivasan, G.; Ramalingam, P.V.

2008-01-01

Condenser cooling and service water systems together serve as the cooling water system of Fast Breeder Test Reactor (FBTR). Palar river water serves as the make-up to the cooling water system. Initially, the service water system alone was commissioned in phases depending upon the arrival of auxiliary equipments at site. During this period, the water was not treated chemically and it also inadvertently remained stagnant for some time in some systems. Thereafter, a threshold chemical treatment was started. However, pin-hole leaks and reduced flow through the heat exchangers were observed and therefore chemical cleaning of headers was done and small diameter pipelines were replaced. Following this a full fledged chemistry control with proprietary formulations was initiated. Later the condenser cooling system was commissioned and the chemical treatment was reviewed. With adoption of improved monitoring methodology and treatment formulation satisfactory corrosion control (< 3 mpy) with minimum deposition problem in this system could be achieved. The primary coolant (primary sodium) of FBTR transfers the nuclear heat to the secondary coolant (secondary sodium) that in turn transfers heat to water in Once Through Steam Generator (OTSG) to generate superheated steam (480 deg C at 125 bar). Efficient water chemistry control plays the vital role in minimizing corrosion related failures of steam generator tubes and ensuring steam generator tube integrity. Therefore, the technical specifications of chemistry parameters of feed/steam water at FBTR are made very stringent to maintain the purity of water at the best attainable level. To meet this stringent feed water and steam quality specifications, online monitoring techniques have been employed in the steam/water circuit to get continuous information about the purity. These monitors have helped significantly in achieving the required feed water quality and running the steam generator for more than 25000 hours without any tube

THE INFORMATION CONTENT OF THE FARM AND UNIT LEVEL NUTRIENT BALANCES FOR THE MANAGEMENT

Directory of Open Access Journals (Sweden)

T SOMOGYI

2007-07-01

Full Text Available The farm gate balance is well known from the environmental literature. This method is not suitable in every case to show the nutrient load for the environment of agricultural companies that is the reason why unit level internal nutrient balances are applied to express the level of nutrient pollution on the environment. These also help to determine the source of the pollution. With the survey of the nutrient flows within the farm we determine the keystones of nutrient management to control the nutrient load of the pollution sources. On the basis of the results and the controlled data of the unit level internal balances we make recommendations for the most appropriate environmental policy instrument to reduce the nutrient pollution.

A coastal surface seawater analyzer for nitrogenous nutrient mapping

Science.gov (United States)

Masserini, Robert T.; Fanning, Kent A.; Hendrix, Steven A.; Kleiman, Brittany M.

2017-11-01

Satellite-data-based modeling of chlorophyll indicates that ocean waters in the mesosphere category are responsible for the majority of oceanic net primary productivity. Coastal waters, which frequently have surface chlorophyll values in the mesosphere range and have strong horizontal chlorophyll gradients and large temporal variations. Thus programs of detailed coastal nutrient surveys are essential to the study of the dynamics of oceanic net primary productivity, along with land use impacts on estuarine and coastal ecosystems. The degree of variability in these regions necessitates flexible instrumentation capable of near real-time analysis to detect and monitor analytes of interest. This work describes the development of a portable coastal surface seawater analyzer for nutrient mapping that can simultaneously elucidate with high resolution the distribution of nitrate, nitrite, and ammonium - the three principal nitrogenous inorganic nutrients in coastal systems. The approach focuses on the use of pulsed xenon flash lamps to construct an analyzer which can be adapted to any automated chemistry with fluorescence detection. The system has two heaters, on-the-fly standardization, on-board data logging, an independent 24 volt direct current power supply, internal local operating network, a 12 channel peristaltic pump, four rotary injection/selection valves, and an intuitive graphical user interface. Using the methodology of Masserini and Fanning (2000) the detection limits for ammonium, nitrite, and nitrate plus nitrite were 11, 10, and 22 nM, respectively. A field test of the analyzer in Gulf of Mexico coastal waters demonstrated its ability to monitor and delineate the complexity of inorganic nitrogen nutrient enrichments within a coastal system.

Nutrient co-limitation at the boundary of an oceanic gyre

Science.gov (United States)

Browning, Thomas J.; Achterberg, Eric P.; Rapp, Insa; Engel, Anja; Bertrand, Erin M.; Tagliabue, Alessandro; Moore, C. Mark

2017-11-01

Nutrient limitation of oceanic primary production exerts a fundamental control on marine food webs and the flux of carbon into the deep ocean. The extensive boundaries of the oligotrophic sub-tropical gyres collectively define the most extreme transition in ocean productivity, but little is known about nutrient limitation in these zones. Here we present the results of full-factorial nutrient amendment experiments conducted at the eastern boundary of the South Atlantic gyre. We find extensive regions in which the addition of nitrogen or iron individually resulted in no significant phytoplankton growth over 48 hours. However, the addition of both nitrogen and iron increased concentrations of chlorophyll a by up to approximately 40-fold, led to diatom proliferation, and reduced community diversity. Once nitrogen-iron co-limitation had been alleviated, the addition of cobalt or cobalt-containing vitamin B12 could further enhance chlorophyll a yields by up to threefold. Our results suggest that nitrogen-iron co-limitation is pervasive in the ocean, with other micronutrients also approaching co-deficiency. Such multi-nutrient limitations potentially increase phytoplankton community diversity.

ANT International chemistry update and best practices

International Nuclear Information System (INIS)

Nordmann, F.; Odar, S.; Venz, H.; Kysela, J.; Ruehle, W.; Riess, R.

2010-01-01

There is an increasing number of Nuclear Power Plants (NPP) in various countries. Their chemistry practices are different due to the variety of designs and experiences while in the past the view was more monolithic. This is allowing a very rich experience that is extremely difficult to fully be aware of. ANT International is now collecting and evaluating these data as well as related R and D Information. This allows interested parties to have an easier access to the various sources of information. The chemistry experts associated to ANT International have been gathering a comprehensive detailed view of: The numerous laboratory data gained all over the world during the past decades; The extensive plant operating experiences with various types of chemistry strategies, crosschecked for various types of reactors designs and materials; An experienced international knowledge able to give the comprehensive overview that young engineers now in charge of many other activities are unable to fully cover. This paper gives the core conclusions of the detailed ANT International reports and results that have recently been gathered in the area of chemistry. It particularly covers: The primary water chemistry and its relation with radionuclides, dose rates and fuel behaviour; The secondary water chemistry focusing on its rationale selection depending on materials, design and other constraints; The start up and shutdown chemistry with it large variety of practices hardly understandable even for some experts; and, The maintenance remedies such as decontamination, steam generator cleaning and its alternate options. Various types of Reactor designs (PWR, VVER, BWR, CANDU®) are considered. The different materials, for example the impact of steam generator tubing and its evolution on the secondary water chemistry rationale or on the radioactivity built-up in the primary coolant, are described. The ways to improve the plant operation with a long term reliability as well as the most

What History Tells Us about the Distinct Nature of Chemistry.

Science.gov (United States)

Chang, Hasok

2017-11-01

Attention to the history of chemistry can help us recognise the characteristics of chemistry that have helped to maintain it as a separate scientific discipline with a unique identity. Three such features are highlighted in this paper. First, chemistry has maintained a distinct type of theoretical thinking, independent from that of physics even in the era of quantum chemistry. Second, chemical research has always been shaped by its ineliminable practical relevance and usefulness. Third, the lived experience of chemistry, spanning the laboratory, the classroom and everyday life, is distinctive in its multidimensional sensuousness. Furthermore, I argue that the combination of these three features makes chemistry an exemplary science.

Advances in water chemistry control for BWRs and PWRs

International Nuclear Information System (INIS)

Wood, C.J.

1997-01-01

This paper is an overview of the effects of water chemistry developments on the current operation of nuclear power plants in the United States, and the mitigation of corrosion-related degradation processes and radiation field build-up processes through the use of advanced water chemistry. Recent modifications in water chemistry to control and reduce radiation fields are outlined, including revisions to the EPRI water chemistry guidelines for BWRs and PWR primary and secondary systems. The change from a single water chemistry specification for all plants to a set of options, from which a plant-specific chemistry programme can be defined, is described. (author)

Nutrient enhanced coastal ocean productivity in the north Gulf of Mexico: understanding the effects of nutrients on a coastal ecosystem

OpenAIRE

1999-01-01

The continental shelf adjacent to the Mississippi River is a highly productive system, often referred to as the fertile fisheries crescent. This productivity is attributed to the effects of the river, especially nutrient delivery. In the later decades of the 2oth century, though, changes in the system were becoming evident. Nutrient loads were seen to be increasing and reports of hypoxia were becoming more frequent. During most recent summers, a broad area (up to 20,000 krn2) of near botto...

Course on Advanced Analytical Chemistry and Chromatography

DEFF Research Database (Denmark)

Andersen, Jens Enevold Thaulov; Fristrup, Peter; Nielsen, Kristian Fog

2011-01-01

Methods of analytical chemistry constitute an integral part of decision making in chemical research, and students must master a high degree of knowledge, in order to perform reliable analysis. At DTU departments of chemistry it was thus decided to develop a course that was attractive to master...... students of different direction of studies, to Ph.D. students and to professionals that need an update of their current state of skills and knowledge. A course of 10 ECTS points was devised with the purpose of introducing students to analytical chemistry and chromatography with the aim of including theory...

Lateral diffusion of nutrients by mammalian herbivores in terrestrial ecosystems.

Directory of Open Access Journals (Sweden)

Adam Wolf

Full Text Available Animals translocate nutrients by consuming nutrients at one point and excreting them or dying at another location. Such lateral fluxes may be an important mechanism of nutrient supply in many ecosystems, but lack quantification and a systematic theoretical framework for their evaluation. This paper presents a mathematical framework for quantifying such fluxes in the context of mammalian herbivores. We develop an expression for lateral diffusion of a nutrient, where the diffusivity is a biologically determined parameter depending on the characteristics of mammals occupying the domain, including size-dependent phenomena such as day range, metabolic demand, food passage time, and population size. Three findings stand out: (a Scaling law-derived estimates of diffusion parameters are comparable to estimates calculated from estimates of each coefficient gathered from primary literature. (b The diffusion term due to transport of nutrients in dung is orders of magnitude large than the coefficient representing nutrients in bodymass. (c The scaling coefficients show that large herbivores make a disproportionate contribution to lateral nutrient transfer. We apply the diffusion equation to a case study of Kruger National Park to estimate the conditions under which mammal-driven nutrient transport is comparable in magnitude to other (abiotic nutrient fluxes (inputs and losses. Finally, a global analysis of mammalian herbivore transport is presented, using a comprehensive database of contemporary animal distributions. We show that continents vary greatly in terms of the importance of animal-driven nutrient fluxes, and also that perturbations to nutrient cycles are potentially quite large if threatened large herbivores are driven to extinction.

The impact of multiple show-ups on eyewitness decision-making and innocence risk.

Science.gov (United States)

Smith, Andrew M; Bertrand, Michelle; Lindsay, R C L; Kalmet, Natalie; Grossman, Deborah; Provenzano, Daniel

2014-09-01

If an eyewitness rejects a show-up, police may respond by finding a new suspect and conducting a second show-up with the same eyewitness. Police may continue finding suspects and conducting show-ups until the eyewitness makes an identification (Study 1). Relatively low criterion-setting eyewitnesses filter themselves out of the multiple show-ups procedure by choosing the first suspect with whom they are presented (Studies 2 and 3). Accordingly, response bias was more stringent on the second show-up when compared with the first, but became no more stringent with additional show-ups. Despite this stringent shift in response bias, innocence risk increased with additional show-ups, as false alarms cumulate (Studies 2 and 3). Although unbiased show-up instructions decreased innocent suspect identifications, the numbers were still discouraging (Study 4). Given the high number of innocent suspects who would be mistakenly identified through the use of multiple show-up procedures, using such identifications as evidence of guilt is questionable. Although evidence of guilt is limited to identifications from a single show-up, practical constraints might sometimes require police to use additional show-ups. Accordingly, we propose a stronger partition between evidentiary and investigative procedures. PsycINFO Database Record (c) 2014 APA, all rights reserved.

User-inspired Research Quantifies How Floodplain Restoration Paired With Cover Crops Reduces Nutrient Export From an Agricultural Catchment Translating to Conservation Success in the Midwestern Cornbelt.

Science.gov (United States)

Tank, J. L.; Hanrahan, B.; Christopher, S. F.; Mahl, U. H.; Royer, T. V.

2017-12-01

The Midwestern US has undergone extensive land use change as forest, wetlands, and prairies have been converted to agroecosystems. Today, excess fertilizer nutrients from farm fields enter agricultural streams, which degrades both local and downstream water quality. We are quantifying the nutrient reduction benefits of two conservation practices implemented at the catchment scale. In partnership with The Nature Conservancy, in a small Indiana catchment, we have quantified how 600m of floodplain restoration (i.e., a two-stage ditch) increased nitrate-N removal via denitrification and reduced sediment export, but impacts on stream nutrient concentrations were negligible due to very high catchment loading relative to the short implementation reach. Requests from state and federal partners led to development and parameterization of a new two-stage ditch module in the SWAT model to determine the potential catchment-scale benefits when implementation lengths were extended. More recently, in partnership with state SWCD managers, we have added a landscape practice to quantify how winter cover crops reduce nutrient loss from fields, sampling year-round nutrient fluxes from multiple subsurface tile drains and longitudinally along the stream channel. Nitrate-N and dissolved P fluxes were significantly lower in tiles draining fields with cover crops compared to those without. At the urging of farmers and federal NRCS partners, we also linked tile drain nutrient reductions to changes in soil chemistry. Both soil nitrate-N and dissolved P were lower in cover cropped fields, and we found significant correlations between soil and tile drain nutrients, which may encourage future adoption of the conservation practice as soil health benefits appeal to farmers. As biogeochemists, this research has provided valuable insights on how floodplains and land cover change can alter patterns of catchment-scale nutrient export. The translation of successful soil and water quality outcomes

Parent's responses to nutrient claims and sports celebrity endorsements on energy-dense and nutrient-poor foods: an experimental study.

Science.gov (United States)

Dixon, Helen; Scully, Maree; Wakefield, Melanie; Kelly, Bridget; Chapman, Kathy; Donovan, Robert

2011-06-01

To assess parents' responses to common, potentially misleading strategies for marketing energy-dense and nutrient-poor (EDNP) child-oriented foods. Between-subjects online experiment to test whether nutrient claims and sports celebrity endorsements on the front of packs of EDNP products lead parents to prefer and rate these foods more favourably. Australia. A total of 1551 parents of children aged 5-12 years, who were the main household grocery buyers. Inclusion of nutrient claims or sports celebrity endorsements on EDNP products led parents to perceive these products to be more nutritious than if they did not include such promotions. When asked to choose between a pair of different products (EDNP v. healthier), 56 % of parents did not read a nutrition information panel (NIP) before making their choice and this did not differ by promotion condition. These parents were more likely to choose an EDNP product if it included a nutrient claim (OR = 1.83, 95 % CI 1.31, 2.56; P foods are available to children at home, it is critical that initiatives aimed at reducing the persuasive impact of food marketing include this target group.

Large-scale photochemical reactions of nanocrystalline suspensions: a promising green chemistry method.

Science.gov (United States)

Veerman, Marcel; Resendiz, Marino J E; Garcia-Garibay, Miguel A

2006-06-08

Photochemical reactions in the solid state can be scaled up from a few milligrams to 10 grams by using colloidal suspensions of a photoactive molecular crystal prepared by the solvent shift method. Pure products are recovered by filtration, and the use of H(2)O as a suspension medium makes this method a very attractive one from a green chemistry perspective. Using the photodecarbonylation of dicumyl ketone (DCK) as a test system, we show that reaction efficiencies in colloidal suspensions rival those observed in solution. [reaction: see text

Chemistry in water reactors

International Nuclear Information System (INIS)

Hermansson, H.P.; Norring, K.

1994-01-01

The international conference Chemistry in Water Reactors was arranged in Nice 24-27/04/1994 by the French Nuclear Energy Society. Examples of technical program areas were primary chemistry, operational experience, fundamental studies and new technology. Furthermore there were sessions about radiation field build-up, hydrogen chemistry, electro-chemistry, condensate polishing, decontamination and chemical cleaning. The conference gave the impression that there are some areas that are going to be more important than others during the next few years to come. Cladding integrity: Professor Ishigure from Japan emphasized that cladding integrity is a subject of great concern, especially with respect to waterside corrosion, deposition and release of crud. Chemistry control: The control of the iron/nickel concentration quotient seems to be not as important as previously considered. The future operation of a nuclear power plant is going to require a better control of the water chemistry than achievable today. One example of this is solubility control via regulation in BWR. Trends in USA: means an increasing use of hydrogen, minimization of SCC/IASCC, minimization of radiation fields by thorough chemistry control, guarding fuel integrity by minimization of cladding corrosion and minimization of flow assisted corrosion. Stellite replacement: The search for replacement materials will continue. Secondary side crevice chemistry: Modeling and practical studies are required to increase knowledge about the crevice chemistry and how it develops under plant operation conditions. Inhibitors: Inhibitors for IGSCC and IGA as well for the primary- (zinc) as for the secondary side (Ti) should be studied. The effects and mode of operation of the inhibitors should be documented. Chemical cleaning: of heat transfer surfaces will be an important subject. Prophylactic cleaning at regular intervals could be one mode of operation

Presidential Green Chemistry Challenge: 2009 Academic Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2009 award winner, Professor Krzysztof Matyjaszewski, developed Atom Transfer Radical Polymerization to make polymers with copper catalysts and environmentally friendly reducing agents.

Ektor discovers again the make-up heating; Ektor reinvente le chauffage d'appoint

Energy Technology Data Exchange (ETDEWEB)

Anon.

2003-03-01

Butagaz perfected a ground breaking make-up heating which answer the consumers demand, hopeful its esthetic, comfort use and safety. The technical characteristic and design advantages of this liquefied petroleum gas heating, are presented. (A.L.B.)

Making Sense of Olive Oil: Simple Experiments to Connect Sensory Observations with the Underlying Chemistry

Science.gov (United States)

Blatchly, Richard A.; Delen, Zeynep; O'Hara, Patricia B.

2014-01-01

In the last decade, our understanding of the chemistry of olive oil has dramatically improved. Here, the essential chemistry of olive oil and its important minor constituents is described and related to the typical sensory categories used to rate and experience oils: color, aroma, bitterness, and pungency. We also describe experiments to explore…

Some remarks on applied radiation chemistry

International Nuclear Information System (INIS)

Sakurada, I.

1979-01-01

Radiation induced polymerization and grafting are two important reactions in the processing. Numerous reports concerning these subjects have appeared in the literature. There are, however, still many problems which have been left unsolved or neglected. Several problems will be taken up in this paper and discussed on experiments carried out in Osaka Laboratory for Radiation Chemistry and Department of Polymer Chemistry of Kyoto University. (author)

Mussels as a tool for mitigation of nutrients in the marine environment

DEFF Research Database (Denmark)

Petersen, Jens Kjerulf; Hasler, Berit; Timmermann, Karen

2014-01-01

Long-line mussel farming has been proposed as a mitigation tool for removal of excess nutrients in eutrophic coastal waters. A full-scale mussel farm optimized for cost efficient nutrient removal was established in the eutrophic Skive Fjord, Denmark where biological and economic parameters related...... to establishment, maintenance and harvest revealed that mussel production optimized for mitigation can be carried out at a lower cost compared to mussel production for (human) consumption. The costs for nutrient removal was 14.8€kg−1N making mitigation mussel production a cost-efficient measure compared...

Modulation of nutrient composition of black soldier fly (Hermetia illucens) larvae by feeding seaweed-enriched media.

Science.gov (United States)

Liland, Nina S; Biancarosa, Irene; Araujo, Pedro; Biemans, Daan; Bruckner, Christian G; Waagbø, Rune; Torstensen, Bente E; Lock, Erik-Jan

2017-01-01

Black soldier fly (Hermetia illucens) larvae are a promising source of protein and lipid for animal feeds. The nutritional composition of the BSF larvae depend partly on the composition of the feeding medium. The BSF lipid profile in part mimics the feeding media lipid profile, and micronutrients, like minerals and vitamins, can readily accumulate in black soldier fly larvae. However, investigative studies on bioconversion and accumulation of nutrients from media to black soldier fly larvae are scarce. Here we show that inclusion of the brown algae Ascophyllum nodosum in the substrate for black soldier fly larvae can introduce valuable nutrients, commonly associated with the marine environment, into the larvae. The omega-3 fatty acid eicosapentaenoic acid (20:5n-3), iodine and vitamin E concentrations increased in the larvae when more seaweed was included in the diet. When the feeding media consisted of more than 50% seaweed, the larvae experienced poorer growth, lower nutrient retention and lower lipid levels, compared to a pure plant based feeding medium. Our results confirm the plasticity of the nutritional make-up of black soldier fly larvae, allowing it to accumulate both lipid- and water-soluble compounds. A broader understanding of the effect of the composition of the feeding media on the larvae composition can help to tailor black soldier fly larvae into a nutrient profile more suited for specific feed or food purposes.

On the use of unsaturated flow and transport models in nutrient and pesticide management

NARCIS (Netherlands)

Vanclooster, M.; Boesten, J.J.T.I.; Tiktak, A.; Jarvis, N.; Kroes, J.G.; Muñoz-Carpena, R.; Clothier, B.E.; Green, S.R.

2004-01-01

In this paper, we show how flow and transport models are introduced in the nutrient and pesticide management decision-making process. Examples are given of the use of flow and transport models in (i) field-scale nutrient and pesticide management; (ii) the identification and evaluation of

Biocorrosion and biofilm formation in a nutrient limited heating system subjected to alternating microaerophilic conditions.

Science.gov (United States)

Kjellerup, B V; Kjeldsen, K U; Lopes, F; Abildgaard, L; Ingvorsen, K; Frølund, B; Sowers, K R; Nielsen, P H

2009-11-01

Severe biofilm formation and biocorrosion have been observed in heating systems even when the water quality complied with existing standards. The coupling between water chemistry, biofilm formation, species composition, and biocorrosion in a heating system was investigated by adding low concentrations of nutrients and oxygen under continuous and alternating dosing regimes. Molecular analysis of 16S rRNA gene fragments demonstrated that the amendments did not cause changes in the overall bacterial community composition. The combined alternating dosing of nutrients and oxygen caused increased rates of pitting (bio-) corrosion. Detection of bacteria involved in sulfide production and oxidation by retrieval of the functional dsrAB and apsA genes revealed the presence of Gram-positive sulfate- and sulfite-reducers and an unknown sulfur-oxidizer. Therefore, to control biocorrosion, sources of oxygen and nutrients must be limited, since the effect of the alternating operational conditions apparently is more important than the presence of potentially corrosive biofilm bacteria.

Thirteen textbooks of basic chemistry and their treatment of radioactivity

International Nuclear Information System (INIS)

Mueller, G.; Navarrete, M.; Martinez, T.; Cabrera, L.

2009-01-01

Nuclear chemistry is usually associated with great disasters, especially the atomic bomb; this without reflecting that knowledge of nuclear chemistry has also had many benefits in the field of medicine and health. Whereas in technologically advanced countries, nuclear chemistry is considered to be an important part of the syllabus, including topics such as radioactivity with the emphasis in making conscience in the common citizen of the inherent benefits. (author)

The Application of Isotope Techniques in Nutrient Assessment and Management in Riverine Systems. Present and Future

Energy Technology Data Exchange (ETDEWEB)

Ito, M.; Newman, B. D. [International Atomic Energy Agency, Isotope Hydrology Section, Vienna (Austria); Hadwen, W. L. [Australian Rivers Institute, Griffith School of Environment, Griffith University - Nathan Campus, Brisbane, Queensland (Australia); Rogers, K. [National Isotope Center, GNS Science, Lower Hutt (New Zealand); Mayer, B. [Department of Geoscience, University of Calgary, Calgary, Alberta (Canada); Hein, T. [Wasser Cluster Lunz, Interuniversitary Center for Aquatic Research, Lunz-See, and University of Natural Resources and Applied Life Sciences, Institute of Hydrobiology and Aquatic Ecosystem Management, Vienna (Austria); Stellato, L. [Centre for Isotopic Research on Cultural and Environmental Heritage (CIRCE), Seconda Universita degli Studi di Napoli, Caserta (Italy); Ohte, N. [Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo (Japan); Mclaughlin, K. [Southern California Coastal Water Research Project, Costa Mesa, California (United States)

2013-05-15

A variety of sources contribute to nutrients in rivers and nutrients may subsequently take various pathways and undergo different transformation processes. We first review representative types of isotopes and the roles of isotope techniques that have been or could be used for nutrient assessment and management. We then present technical, financial and logistical matters to be considered in selecting appropriate isotope techniques for nutrient assessment and management. Lastly we propose several approaches on the application of isotope techniques to make more effective the studies and management of nutrients in rivers in the near future. (author)

Dopamine alleviates nutrient deficiency-induced stress in Malus hupehensis.

Science.gov (United States)

Liang, Bowen; Li, Cuiying; Ma, Changqing; Wei, Zhiwei; Wang, Qian; Huang, Dong; Chen, Qi; Li, Chao; Ma, Fengwang

2017-10-01

Dopamine mediates many physiological processes in plants. We investigated its role in regulating growth, root system architecture, nutrient uptake, and responses to nutrient deficiencies in Malus hupehensis Rehd. Under a nutrient deficiency, plants showed significant reductions in growth, chlorophyll concentrations, and net photosynthesis, along with disruptions in nutrient uptake, transport, and distribution. However, pretreatment with 100 μM dopamine markedly alleviated such inhibitions. Supplementation with that compound enabled plants to maintain their photosynthetic capacity and development of the root system while promoting the uptake of N, P, K, Ca, Mg, Fe, Mn, Cu, Zn, and B, altering the way in which those nutrients were partitioned throughout the plant. The addition of dopamine up-regulated genes for antioxidant enzymes involved in the ascorbate-glutathione cycle (MdcAPX, MdcGR, MdMDHAR, MdDHAR-1, and MdDHAR-2) but down-regulated genes for senescence (SAG12, PAO, and MdHXK). These results indicate that exogenous dopamine has an important antioxidant and anti-senescence effect that might be helpful for improving nutrient uptake. Our findings demonstrate that dopamine offers new opportunities for its use in agriculture, especially when addressing the problem of nutrient deficiencies. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Presidential Green Chemistry Challenge: 2003 Academic Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2003 award winner, Professor Richard A. Gross, developed a transesterification to make polyol-containing polyesters using lipase, replacing heavy metal catalysts and hazardous solvents.

Gallium and copper radiopharmaceutical chemistry

International Nuclear Information System (INIS)

Green, M.A.

1991-01-01

Gallium and copper radionuclides have a long history of use in nuclear medicine. Table 1 presents the nuclear properties of several gallium and copper isotopes that either are used in the routine practice of clinical nuclear medicine or exhibit particular characteristics that might make them useful in diagnostic or therapeutic medicine. This paper will provide some historic perspective along with an overview of some current research directions in gallium and copper radiopharmaceutical chemistry. A more extensive review of gallium radiopharmaceutical chemistry has recently appeared and can be consulted for a more in-depth treatment of this topic

Selective host molecules obtained by dynamic adaptive chemistry.

Science.gov (United States)

Matache, Mihaela; Bogdan, Elena; Hădade, Niculina D

2014-02-17

Up till 20 years ago, in order to endow molecules with function there were two mainstream lines of thought. One was to rationally design the positioning of chemical functionalities within candidate molecules, followed by an iterative synthesis-optimization process. The second was the use of a "brutal force" approach of combinatorial chemistry coupled with advanced screening for function. Although both methods provided important results, "rational design" often resulted in time-consuming efforts of modeling and synthesis only to find that the candidate molecule was not performing the designed job. "Combinatorial chemistry" suffered from a fundamental limitation related to the focusing of the libraries employed, often using lead compounds that limit its scope. Dynamic constitutional chemistry has developed as a combination of the two approaches above. Through the rational use of reversible chemical bonds together with a large plethora of precursor libraries, one is now able to build functional structures, ranging from quite simple molecules up to large polymeric structures. Thus, by introduction of the dynamic component within the molecular recognition processes, a new perspective of deciphering the world of the molecular events has aroused together with a new field of chemistry. Since its birth dynamic constitutional chemistry has continuously gained attention, in particular due to its ability to easily create from scratch outstanding molecular structures as well as the addition of adaptive features. The fundamental concepts defining the dynamic constitutional chemistry have been continuously extended to currently place it at the intersection between the supramolecular chemistry and newly defined adaptive chemistry, a pivotal feature towards evolutive chemistry. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Real time water chemistry monitoring and diagnostics

International Nuclear Information System (INIS)

Gaudreau, T.M.; Choi, S.S.

2002-01-01

EPRI has produced a real time water chemistry monitoring and diagnostic system. This system is called SMART ChemWorks and is based on the EPRI ChemWorks codes. System models, chemistry parameter relationships and diagnostic approaches from these codes are integrated with real time data collection, an intelligence engine and Internet technologies to allow for automated analysis of system chemistry. Significant data management capabilities are also included which allow the user to evaluate data and create automated reporting. Additional features have been added to the system in recent years including tracking and evaluation of primary chemistry as well as the calculation and tracking of primary to secondary leakage in PWRs. This system performs virtual sensing, identifies normal and upset conditions, and evaluates the consistency of on-line monitor and grab sample readings. The system also makes use of virtual fingerprinting to identify the cause of any chemistry upsets. This technology employs plant-specific data and models to determine the chemical state of the steam cycle. (authors)

Nutrient cycling strategies.

NARCIS (Netherlands)

Breemen, van N.

1995-01-01

This paper briefly reviews pathways by which plants can influence the nutrient cycle, and thereby the nutrient supply of themselves and of their competitors. Higher or lower internal nutrient use efficiency positively feeds back into the nutrient cycle, and helps to increase or decrease soil

Atmosphere physics and chemistry

International Nuclear Information System (INIS)

Delmas, R.; Megie, G.; Peuch, V.H.

2005-10-01

Since the 1970's, the awareness about the atmospheric pollution threat has led to a spectacular development of the researches on the complex interactions between the chemical composition of the atmosphere and the climate. This book makes a synthesis of the state-of-the-art in this very active domain of research. Content: introduction, atmosphere dynamics and transport, matter-radiation interaction and radiant transfer, physico-chemical processes, atmospheric aerosol and heterogenous chemistry, anthropic and natural emissions and deposition, stratospheric chemical system, tropospheric chemical system, polluted boundary layer, paleo-environments and ice archives, role of atmospheric chemistry in global changes, measurement principles and instruments, numerical modeling, experimental strategy, regulation and management of the atmospheric environment, index. (J.S.)

Water-Chemistry and Its Utility Systems in CCP Power Units (Review)

Science.gov (United States)

Larin, B. M.

2018-01-01

Damageability of heat transfer surfaces of waste heat recovery steam generators (HRSG) of combined- cycle plants (CCP) can be reduced due to an increase in the quality of make-up and feed water, the use of phosphate-alkaline or amino compound water chemistry (WC), and improved chemical quality control of the heat carrier and make-up water preparation techniques. Temporary quality standards for the heat medium developed by the All-Russia Thermal Engineering institute (VTI) for CCP power units are presented in comparison with the IAPWS standards; preferences for the choice of a WC type for some power units commissioned in Russia in the first decade of this century are shown; and operational data on the quality of feed, boiler water, and steam for two large CCP-450 and CCP-425 power units are given. The state and prospects for the development of chemical-technological monitoring systems and CCP water treatment plants are noted. Estimability of some CCP diagnostic parameters by measuring specific electric conductivity and pH is shown. An extensive bibliography on this topic is given.

Fiscal 1999 survey report. Part 2. Research study on restraint of carbon dioxide generation by green chemistry; 1999 nendo green chemistry ni yoru CO{sub 2} hassei yokusei ni kakawaru chosa kenkyu. 2

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

In connection with green chemistry, a concept of bringing paradigm shift to chemical technologies as something that makes reduction in environmental load compatible with economic activities; surveys were made this year on the developments of fine chemicals from renewable resources such as cellulose among the cases of developing chemical substances/products to be called 'green chemicals' reducing environmental load; developments of surfactants produced by certain microorganism, plastic additives with reduced pollutant loads, particularly fire retardants and environmentally benign reactant solvents; concept of green chemistry in the development of chlorofluorocarbon-alternatives; and up-to-date technological level concerning a design method of chemical materials and an estimation method for chemical safety using quantum chemistry calculation. In regard to the chemical materials and products intrinsically containing a certain level of risk, R and D should be reinforced and accelerated in the future on the alternative materials/products reducing their toxicity. In this case, along with the importance of discussing compatibility of technological possibility with economical adaptability, sociological study seems to be necessary in incorporating environmental load reduction into economic evaluation. (NEDO)

Diagnosis of nutrient imbalances with vector analysis in agroforestry systems.

Science.gov (United States)

Isaac, Marney E; Kimaro, Anthony A

2011-01-01

Agricultural intensification has had unintended environmental consequences, including increased nutrient leaching and surface runoff and other agrarian-derived pollutants. Improved diagnosis of on-farm nutrient dynamics will have the advantage of increasing yields and will diminish financial and environmental costs. To achieve this, a management support system that allows for site-specific rapid evaluation of nutrient production imbalances and subsequent management prescriptions is needed for agroecological design. Vector diagnosis, a bivariate model to depict changes in yield and nutritional response simultaneously in a single graph, facilitates identification of nutritional status such as growth dilution, deficiency, sufficiency, luxury uptake, and toxicity. Quantitative data from cocoa agroforestry systems and pigeonpea intercropping trials in Ghana and Tanzania, respectively, were re-evaluated with vector analysis. Relative to monoculture, biomass increase in cocoa ( L.) under shade (35-80%) was accompanied by a 17 to 25% decline in P concentration, the most limiting nutrient on this site. Similarly, increasing biomass with declining P concentrations was noted for pigeonpea [ (L). Millsp.] in response to soil moisture availability under intercropping. Although vector analysis depicted nutrient responses, the current vector model does not consider non-nutrient resource effects on growth, such as ameliorated light and soil moisture, which were particularly active in these systems. We revisit and develop vector analysis into a framework for diagnosing nutrient and non-nutrient interactions in agroforestry systems. Such a diagnostic technique advances management decision-making by increasing nutrient precision and reducing environmental issues associated with agrarian-derived soil contamination. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

Ethics in Science: The Unique Consequences of Chemistry.

Science.gov (United States)

Kovac, Jeffrey

2015-01-01

This article discusses the ethical issues unique to the science and practice of chemistry. These issues arise from chemistry's position in the middle between the theoretical and the practical, a science concerned with molecules that are of the right size to directly affect human life. Many of the issues are raised by the central activity of chemistry--synthesis. Chemists make thousands of new substances each year. Many are beneficial, but others are threats. Since the development of the chemical industry in the nineteenth century, chemistry has contributed to the deterioration of the environment but has also helped to reduce pollution. Finally, we discuss the role of codes of ethics and whether the current codes of conduct for chemists are adequate for the challenges of today's world.

Presidential Green Chemistry Challenge: 1999 Academic Award

Science.gov (United States)

Presidential Green Chemistry Challenge 1999 award winner, Professor Terry Collins, developed a series of TAML oxidant activators that work with hydrogen peroxide to replace chlorine bleaches for paper making and laundry.

Presidential Green Chemistry Challenge: 2005 Academic Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2005 award winner, Professor Robin D. Rogers, used ionic liquids to dissolve and process cellulose from wood, cloth, or paper to make new biorenewable or biocompatible materials.

Capturing Chemistry in Action with Electrons: Realization of Atomically Resolved Reaction Dynamics.

Science.gov (United States)

Ischenko, Anatoly A; Weber, Peter M; Miller, R J Dwayne

2017-08-23

One of the grand challenges in chemistry has been to directly observe atomic motions during chemical processes. The depiction of the nuclear configurations in space-time to understand barrier crossing events has served as a unifying intellectual theme connecting the different disciplines of chemistry. This challenge has been cast as an imaging problem in which the technical issues reduce to achieving not only sufficient simultaneous space-time resolution but also brightness for sufficient image contrast to capture the atomic motions. This objective has been met with electrons as the imaging source. The review chronicles the first use of electron structural probes to study reactive intermediates, to the development of high bunch charge electron pulses with sufficient combined spatial-temporal resolution and intensity to literally light up atomic motions, as well as the means to characterize the electron pulses in terms of temporal brightness and image reconstruction. The use of femtosecond Rydberg spectroscopy as a novel means to use internal electron scattering within the molecular reference frame to obtain similar information on reaction dynamics is also discussed. The focus is on atomically resolved chemical reaction dynamics with pertinent references to work in other areas and forms of spectroscopy that provide additional information. Effectively, we can now directly observe the far-from-equilibrium atomic motions involved in barrier crossing and categorize chemistry in terms of a power spectrum of a few dominant reaction modes. It is this reduction in dimensionality that makes chemical reaction mechanisms transferrable to seemingly arbitrarily complex (large N) systems, up to molecules as large as biological macromolecules (N > 1000 atoms). We now have a new way to reformulate reaction mechanisms using an experimentally determined dynamic mode basis that in combination with recent theoretical advances has the potential to lead to a new conceptual basis for

Mathematical modelling of the influenced of diffusion rate on macro nutrient availability in paddy field

Science.gov (United States)

Renny; Supriyanto

2018-04-01

Nutrition is the chemical compounds that needed by the organism for the growth process. In plants, nutrients are organic or inorganic compounds that are absorbed from the roots of the soil. It consist of macro and micro nutrient. Macro nutrients are nutrition that needed by plants in large quantities, such as, nitrogen, calcium, pottacium, magnesium, and sulfur. The total soil nutrient is the difference between the input nutrient and the output nutrients. Input nutrients are nutrient that derived from the decomposition of organic substances. Meanwhile, the output nutrient consists of the nutrients that absorbed by plant roots (uptake), the evaporated nutrients (volatilized) and leached nutrients. The nutrient transport can be done through diffusion process. The diffusion process is essential in removing the nutrient from one place to the root surface. It will cause the rate of absorption of nutrient by the roots will be greater. Nutrient concept in paddy filed can be represented into a mathematical modelling, by making compartment models. The rate of concentration change in the compartment model forms a system of homogeneous linear differential equations. In this research, we will use Laplaces transformation to solve the compartment model and determined the dynamics of macro nutrition due to diffusion process.

All-union conference on theoretical and applied radiation chemistry

Energy Technology Data Exchange (ETDEWEB)

Putilov, A.V.; Barashkov, N.N.

1985-01-01

The All-Union Conference on Theoretical and Applied Radiation Chemistry was held in Obninsk in October 1984. The subjects covered by the all-union conference included practically all urgent problems of modern radiation chemistry: theoretical principles of radiation chemistry, solid state radiation chemistry, radiation chemistry of heterogeneous processes, radiolysis of organic and inorganic substances, radiation polymerization and hardening, radiation chemistry of polymers, the technology of radiation chemistry and instrument making. Twenty-three plenary reports given by scientists representing the corresponding directions were devoted to an examination of the basic problems of modern radiation chemistry. Around 100 oral communications were heard and discussed at meetings of six sections operating within the framework of the conference. In addition the conference participants were able to acquaint themselves with and discuss more than 230 displays in parallel with the oral reports. Abstracts of all of the section oral reports and displays were published by the organizing committee in the form of a separate collection. The texts of the plenary reports were published in the journal Khimiya Vysokikh Energiy in 1985.

Presidential Green Chemistry Challenge: 2008 Academic Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2008 award winners, Professors Robert E. Maleczka, Jr. and Milton R. Smith, III, developed halogen-free, catalytic C-H activation/borylation to make aryl and heteroaryl boronic esters.

Dense interstellar cloud chemistry: Basic issues and possible dynamical solution

International Nuclear Information System (INIS)

Prasad, S.S.; Heere, K.R.; Tarafdar, S.P.

1989-01-01

Standing at crossroad of enthusiasm and frustration, dense intertellar cloud chemistry has a squarely posed fundamental problem: Why do the grains appear to play at best a minor role in the chemistry? Grain surface chemistry creates considerable difficulties when the authors treat dense clouds as static objects and ignore the implications of the processes by which the clouds became dense in the first place. A new generation of models which treat chemical and dynamical evolutions concurrently are therefore presented as possible solution to the current frustrations. The proposed modeling philosophy and agenda could make the next decade quite exciting for interstellar chemistry

Position paper on main areas of nuclear chemistry research and application

International Nuclear Information System (INIS)

2001-01-01

Nuclear chemistry, with its specialized areas of nuclear chemistry, radiochemistry, and radiation chemistry, mainly covers these fields: basic research in nuclear chemistry; actinide chemistry; radioanalysis; nuclear chemistry in the life sciences, geosciences, and cosmic chemistry; radiotracers in technology; nuclear power technology; nuclear waste management; tritium chemistry in fusion technology, and radiation protection and radioecology. In the more than one hundred years of history of this branch of science and technology, which was opened up by the discovery of radioactivity and of the radioelements, pioneering discoveries and developments have been made in many sectors. Far beyond the confines of this area of work, they have achieved overriding importance in applications in many fields of technology and industry and in the life sciences. Research and application in nuclear chemistry continue to be highly relevant to society, ecology, and the economy, and the potential of science and technology in this field in Germany is acknowledged internationally. In the light of this vast area of activity, and against the need to maintain competence in nuclear chemistry for the use of nuclear power, irrespective of the status of this continued use in Germany, nuclear chemistry is indispensable to the solution of future problems. The Nuclear Chemistry Group of the Gesellschaft Deutscher Chemiker therefore uses this position paper to draw attention to the urgent need to keep up and further advance nuclear chemistry applications in a variety of areas of science and technology, also as a public duty of thorough education and research. (orig.) [de

Organic carbamates in drug design and medicinal chemistry.

Science.gov (United States)

Ghosh, Arun K; Brindisi, Margherita

2015-04-09

The carbamate group is a key structural motif in many approved drugs and prodrugs. There is an increasing use of carbamates in medicinal chemistry and many derivatives are specifically designed to make drug-target interactions through their carbamate moiety. In this Perspective, we present properties and stabilities of carbamates, reagents and chemical methodologies for the synthesis of carbamates, and recent applications of carbamates in drug design and medicinal chemistry.

Medicinal chemistry matters - a call for discipline in our discipline.

Science.gov (United States)

Johnstone, Craig

2012-06-01

Medicinal chemistry makes a vital contribution to small molecule drug discovery, and the quality of it contributes directly to research effectiveness as well as to downstream costs, speed and survival in development. In recent years, the discipline of medicinal chemistry has evolved and witnessed many noteworthy contributions that propose and offer potential improvements to medicinal chemistry practice; however, the impact of these ideas is limited by their acceptance and deployment into every-day activity and, as a result, the quality of medicinal chemistry remains variable. For the good of the industry and the medicinal chemistry discipline, there is a need to move from retrospective learning to prospective control of medicinal chemistry practice to improve cost effectiveness, probability of success and survival rates. Copyright © 2012 Elsevier Ltd. All rights reserved.

The nutrient value of Imbrasia belina Lepidoptera: Saturnidae (madora).

Science.gov (United States)

Onigbinde, A O; Adamolekun, B

1998-05-01

To determine the pattern of consumption of Imbrasia belina (madora) and other edible insects and also compare the nutrient values of madora larvae and two of its variants (Anaphe venata and Cirina forda) to those of some conventional sources of protein. University of Zimbabwe. 100 workers who admitted to a history of entomophagy. Popularity score of madora compared with those of other edible insects and approximate compositions of nutrients in the larvae compared with standard proteins. Most respondents (65%) were introduced to entomophagy by their parents. Termites were the most frequently consumed, followed by madora. More respondents ate insects because of their perceived nutritional value than because of their relative availability. There was no association of entomophagy with significant side effects. The protein, fat and mineral contents of the larvae were superior to those of beef and chicken. There were no major differences in the nutrient composition of the three Lepidoptera variants. The high nutrient value and low cost of these larvae make them an important protein supplement, especially for people in the low income group.

Distribution of nutrients in the Periyar river estuary

Digital Repository Service at National Institute of Oceanography (India)

Devi, K.S.; Sankaranarayanan, V.N.; Venugopal, P.

higher values compared to the surface and bottom water. Irregular pattern of distribution of ammonia was recorded at all stations. Early monsoon season showed uniform conditions in this section. Subsequently a build up of nutrients in the mid...

PWR primary system chemistry control during hot functional testing

International Nuclear Information System (INIS)

Reid, Richard D.; Little, Michael J.

2014-01-01

Hot Functional Testing (HFT) involves a number of pre-operational exercises performed to confirm the operability of plant systems at conditions expected during both normal and off-normal operation of a pressurized water reactor (PWR), including operability of safety systems. While the primary purposes of HFT are to demonstrate operability of plant systems and satisfy regulatory requirements, chemistry control during HFT is important to long-term integrity and performance of plant systems. Specifically, HFT is the first time plant equipment is exposed to high temperature water and the chemistry maintained during HFT can impact the passivation layers that form on wetted surfaces and long-term release of metals from these surfaces. Metals released from the inner surfaces of steam generator tubing and reactor coolant loop piping become activated in the core and can redeposit on ex-core surfaces. Because HFT is performed before fuel is loaded in the core, HFT provides an opportunity to produce a passive layer on primary surfaces that is free of activated corrosion products, resistant to metals release during subsequent plant operation, and also resistant to incorporation of activated corrosion products (once fuel is loaded in the core). Thus, maintaining desirable primary chemistry control during HFT is important for source term management, minimization of future shutdown activity releases, minimization of dose rates, and asset preservation. This paper presents an overview of passive film formation in the austenitic stainless steel and high nickel alloys that make up the majority of the primary circuit in advanced PWR designs. Based on this information, a summary is provided of the effects on passive film formation of key chemistry parameters that may be controlled during HFT. (author)

Radiation chemistry of the liquid state

International Nuclear Information System (INIS)

Buxton, G.V.

1987-01-01

More is known about the radiation chemistry of water than any other liquid. From a practical viewpoint out knowledge is virtually complete, and water radiolysis now provides a very convenient way of generating an enormous variety of unstable species under well-defined conditions. This facility, coupled with the techniques of pulse radiolysis, has opened up new areas in aqueous inorganic, organic, and biochemistry that cannot be readily studied by thermal or photochemical methods. This chapter is aimed, therefore, at those who wish to use radiolytic methods to generate and study unstable species in aqueous solution. The basic features of the radiation chemistry of water are described first to show how the primary radical and molecular products evolve with time and to delineate the bounds of useful experimental conditions. Next, the properties of the primary radicals are summarized, and examples are given to show how the primary radicals can be converted into secondary radicals, often of a single kind. This is an important aspect of the radiation chemistry of aqueous solutions. Lastly, the impact of our knowledge of the radiation chemistry of water on advances in general chemistry is illustrated by examples from the fields of inorganic and organic chemistry

Experimental evidence for enhanced top-down control of freshwater macrophytes with nutrient enrichment.

Science.gov (United States)

Bakker, Elisabeth S; Nolet, Bart A

2014-11-01

The abundance of primary producers is controlled by bottom-up and top-down forces. Despite the fact that there is consensus that the abundance of freshwater macrophytes is strongly influenced by the availability of resources for plant growth, the importance of top-down control by vertebrate consumers is debated, because field studies yield contrasting results. We hypothesized that these bottom-up and top-down forces may interact, and that consumer impact on macrophyte abundance depends on the nutrient status of the water body. To test this hypothesis, experimental ponds with submerged vegetation containing a mixture of species were subjected to a fertilization treatment and we introduced consumers (mallard ducks, for 8 days) on half of the ponds in a full factorial design. Over the whole 66-day experiment fertilized ponds became dominated by Elodea nuttallii and ponds without extra nutrients by Chara globularis. Nutrient addition significantly increased plant N and P concentrations. There was a strong interactive effect of duck presence and pond nutrient status: macrophyte biomass was reduced (by 50%) after the presence of the ducks on fertilized ponds, but not in the unfertilized ponds. We conclude that nutrient availability interacts with top-down control of submerged vegetation. This may be explained by higher plant palatability at higher nutrient levels, either by a higher plant nutrient concentration or by a shift towards dominance of more palatable plant species, resulting in higher consumer pressure. Including nutrient availability may offer a framework to explain part of the contrasting field observations of consumer control of macrophyte abundance.

Skeletal nutrient vascular adaptation induced by external oscillatory intramedullary fluid pressure intervention

Directory of Open Access Journals (Sweden)

Qin Yi-Xian

2010-03-01

Full Text Available Abstract Background Interstitial fluid flow induced by loading has demonstrated to be an important mediator for regulating bone mass and morphology. It is shown that the fluid movement generated by the intramedullary pressure (ImP provides a source for pressure gradient in bone. Such dynamic ImP may alter the blood flow within nutrient vessel adjacent to bone and directly connected to the marrow cavity, further initiating nutrient vessel adaptation. It is hypothesized that oscillatory ImP can mediate the blood flow in the skeletal nutrient vessels and trigger vasculature remodeling. The objective of this study was then to evaluate the vasculature remodeling induced by dynamic ImP stimulation as a function of ImP frequency. Methods Using an avian model, dynamics physiological fluid ImP (70 mmHg, peak-peak was applied in the marrow cavity of the left ulna at either 3 Hz or 30 Hz, 10 minutes/day, 5 days/week for 3 or 4 weeks. The histomorphometric measurements of the principal nutrient arteries were done to quantify the arterial wall area, lumen area, wall thickness, and smooth muscle cell layer numbers for comparison. Results The preliminary results indicated that the acute cyclic ImP stimuli can significantly enlarge the nutrient arterial wall area up to 50%, wall thickness up to 20%, and smooth muscle cell layer numbers up to 37%. In addition, 3-week of acute stimulation was sufficient to alter the arterial structural properties, i.e., increase of arterial wall area, whereas 4-week of loading showed only minimal changes regardless of the loading frequency. Conclusions These data indicate a potential mechanism in the interrelationship between vasculature adaptation and applied ImP alteration. Acute ImP could possibly initiate the remodeling in the bone nutrient vasculature, which may ultimately alter blood supply to bone.

Platforms for energy and nutrient recovery from domestic wastewater: A review.

Science.gov (United States)

Batstone, D J; Hülsen, T; Mehta, C M; Keller, J

2015-12-01

Alternative domestic wastewater treatment processes that recover energy and nutrients while achieving acceptable nutrient limits (650mgCODL(-1). PRR offers the possibility for recovery of nitrogen and other nutrients (including potassium) through assimilative recovery. However, the energetic overhead of this is substantial, requiring 5kWhkgN(-1) as electricity, which compares to ammonia fixation costs. The lower energy costs, and near to market status of LEM treatment make it likely as a recovery platform in the shorter term, while ability to recover other elements such as nitrogen and potassium, as well as enhance favourability on concentrated wastewaters may enhance the desirability of partitioning in the longer term. Copyright © 2014 Elsevier Ltd. All rights reserved.

Learning chemistry from text: The effect of decision making

Science.gov (United States)

Pedersen, Jon; J., Ronald; Alice, Bonnstetter; Corkill, J.; Glover, John A.

Two experiments examined the relative effects of questions requiring decisions, statements providing the decision information to students, questions not requiring decisions, and control procedures on students' memory for chemistry text reading materials. Experiment 1 employed immediate recall. The results of Experiment 1 indicated that students who made and justified decisions about the contents recalled significantly more information than students in any other condition. In addition, students who answered questions that did not require decisions recalled significantly more of the content than students in the control or the statements conditions. No other contrasts reached significance. Experiment 2 employed delayed recall assessed one week after reading. The results confirmed those of Experiment 1. The overall results of the study are discussed in terms of an elaboration perspective on memory.

Modulation of nutrient composition of black soldier fly (Hermetia illucens larvae by feeding seaweed-enriched media.

Directory of Open Access Journals (Sweden)

Nina S Liland

Full Text Available Black soldier fly (Hermetia illucens larvae are a promising source of protein and lipid for animal feeds. The nutritional composition of the BSF larvae depend partly on the composition of the feeding medium. The BSF lipid profile in part mimics the feeding media lipid profile, and micronutrients, like minerals and vitamins, can readily accumulate in black soldier fly larvae. However, investigative studies on bioconversion and accumulation of nutrients from media to black soldier fly larvae are scarce. Here we show that inclusion of the brown algae Ascophyllum nodosum in the substrate for black soldier fly larvae can introduce valuable nutrients, commonly associated with the marine environment, into the larvae. The omega-3 fatty acid eicosapentaenoic acid (20:5n-3, iodine and vitamin E concentrations increased in the larvae when more seaweed was included in the diet. When the feeding media consisted of more than 50% seaweed, the larvae experienced poorer growth, lower nutrient retention and lower lipid levels, compared to a pure plant based feeding medium. Our results confirm the plasticity of the nutritional make-up of black soldier fly larvae, allowing it to accumulate both lipid- and water-soluble compounds. A broader understanding of the effect of the composition of the feeding media on the larvae composition can help to tailor black soldier fly larvae into a nutrient profile more suited for specific feed or food purposes.

Decomposition and nutrient release of leguminous plants in coffee agroforestry systems

Directory of Open Access Journals (Sweden)

Eduardo da Silva Matos

2011-02-01

Full Text Available Leguminous plants used as green manure are an important nutrient source for coffee plantations, especially for soils with low nutrient levels. Field experiments were conducted in the Zona da Mata of Minas Gerais State, Brazil to evaluate the decomposition and nutrient release rates of four leguminous species used as green manures (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum and Stylosanthes guianensis in a coffee agroforestry system under two different climate conditions. The initial N contents in plant residues varied from 25.7 to 37.0 g kg-1 and P from 2.4 to 3.0 g kg-1. The lignin/N, lignin/polyphenol and (lignin+polyphenol/N ratios were low in all residues studied. Mass loss rates were highest in the first 15 days, when 25 % of the residues were decomposed. From 15 to 30 days, the decomposition rate decreased on both farms. On the farm in Pedra Dourada (PD, the decomposition constant k increased in the order C. mucunoides < S. aterrimum < S. guianensis < A. pintoi. On the farm in Araponga (ARA, there was no difference in the decomposition rate among leguminous plants. The N release rates varied from 0.0036 to 0.0096 d-1. Around 32 % of the total N content in the plant material was released in the first 15 days. In ARA, the N concentration in the S. aterrimum residues was always significantly higher than in the other residues. At the end of 360 days, the N released was 78 % in ARA and 89 % in PD of the initial content. Phosphorus was the most rapidly released nutrient (k values from 0.0165 to 0.0394 d-1. Residue decomposition and nutrient release did not correlate with initial residue chemistry and biochemistry, but differences in climatic conditions between the two study sites modified the decomposition rate constants.

Diagnosis & Correction of Soil Nutrient Limitations in Intensively managed southern pine forests

Energy Technology Data Exchange (ETDEWEB)

University of Florida

2002-10-25

Forest productivity is one manner to sequester carbon and it is a renewable energy source. Likewise, efficient use of fertilization can be a significant energy savings. To date, site-specific use of fertilization for the purpose of maximizing forest productivity has not been well developed. Site evaluation of nutrient deficiencies is primarily based on empirical approaches to soil testing and plot fertilizer tests with little consideration for soil water regimes and contributing site factors. This project uses mass flow diffusion theory in a modeling context, combined with process level knowledge of soil chemistry, to evaluate nutrient bioavailability to fast-growing juvenile forest stands growing on coastal plain Spodosols of the southeastern U.S. The model is not soil or site specific and should be useful for a wide range of soil management/nutrient management conditions. In order to use the model, field data of fast-growing southern pine needed to be measured and used in the validation of the model. The field aspect of the study was mainly to provide data that could be used to verify the model. However, we learned much about the growth and development of fast growing loblolly. Carbon allocation patterns, root shoot relationships and leaf area root relationships proved to be new, important information. The Project Objectives were to: (1) Develop a mechanistic nutrient management model based on the COMP8 uptake model. (2) Collect field data that could be used to verify and test the model. (3) Model testing.

Nutrient disequilibrium in agro-ecosystems: Concepts and case studies

International Nuclear Information System (INIS)

Smaling, Eric

2002-01-01

Full text: Amongst the problems that African agriculture faces, soil fertility decline is mentioned as a major pressure. The declining state (lower soil fertility) has led to different responses by researchers, landusers and policy makers. All responses directly or indirectly boil down to some form of 'Integrated Nutrient Management' (INM), which is defined as the 'judicious' manipulation of nutrient stocks and flows. As INM is complex and multi-faceted, it is difficult to derive simple indicators for policy makers from it. The concept of stocks (state) and flows (pressure), however, links well with economic sciences. A continental study revealed that Africa is losing nutrients at a rather alarming rate, i.e., 22 kg N, 2.5 kg P and 15 kg K per ha per year (Stoorvogel and Smaling, 1990). These values represent the sum of the outputs minus the sum of the inputs mentioned below. IN 1 mineral fertilizer OUT 1 nutrients in harvested parts, milk, meat, etc. IN 2 organic fertilizer OUT 2 nutrients in removed crop residues IN 3 atmospheric deposition OUT 3 leaching IN 4 biological N fixation OUT 4 gaseous losses IN 5 sedimentation OUT 5 runoff and erosion This study however, commissioned by FAO, had to deal with a lot of higher-scale problems, i.e., using FAO's production yearbooks, using the 1:5,000,000 FAO Soil Map of the World, generalisation, simplification, and the use of proxies (transfer functions). It triggered many studies at lower spatial scales (field, farm, village, watershed), in which inputs and outputs are accompanied by internal flows within the system. In other words, INM can be geared towards: adding nutrients to the system; saving nutrient from being lost from the system; recycling so as to maximize nutrient use efficiency. Measurement of nutrient flows is complex: a simple fertilizer trial implies adding nutrients, and harvesting part of the extra nutrients, but what happens to the nutrients that were not taken up by the crop? More spatially complex is

Physical chemistry and the environment

International Nuclear Information System (INIS)

Dunning, T.H. Jr.; Garrett, B.C.; Kolb, C.E. Jr.; Shaw, R.W.; Choppin, G.R.; Wagner, A.F.

1994-08-01

From the ozone hole and the greenhouse effect to plastics recycling and hazardous waste disposal, society faces a number of issues, the solutions to which require an unprecedented understanding of the properties of molecules. We are coming to realize that the environment is a coupled set of chemical systems, its dynamics determining the welfare of the biosphere and of humans in particular. These chemical systems are governed by fundamental molecular interactions, and they present chemists with an unparalleled challenge. The application of current concepts of molecular behavior and of up-to-date experimental and computational techniques can provide us with insights into the environment that are needed to mitigate past damage, to anticipate the impact of current human activity, and to avoid future insults to the environment. Environmental chemistry encompasses a number of separate, yet interlocking, areas of research. In all of these areas progress is limited by an inadequate understanding of the underlying chemical processes involved. Participation of all chemical approaches -- experimental, theoretical and computational -- and of all disciplines of chemistry -- organic, inorganic, physical, analytical and biochemistry -- will be required to provide the necessary fundamental understanding. The Symposium on ''Physical Chemistry and the Environment'' was designed to bring the many exciting and challenging physical chemistry problems involved in environmental chemistry to the attention of a larger segment of the physical chemistry community

Inorganic and organic radiation chemistry: state and problems

International Nuclear Information System (INIS)

Kalyazin, E.P.; Bugaenko, L.T.

1990-01-01

Radiation inorganic and organic chemistry is presented on the basis of the general scheme and classification of radiolysis products and elementary processes, by which evolution of radiation-affected substances up to the final radiolysis products takes place. The evolution is traced for the representatives of inorganic and organic compounds. The contribution of radiation inorganic and organic chemistry to radiation technology, radiation materials technology, radiation ecology and medicine, is shown. Tendencies in the development of radiation chemistry and prediction of its certain directions are considered

Green Chemistry Challenge: 2017 Greener Synthetic Pathways Award

Science.gov (United States)

Green Chemistry Challenge 2017 award winners, Merck, developed a novel asymmetric aza-Michael cyclization, employing a chemically stable and fully recyclable organocatalyst to make Letermovir, an antiviral drug

Save Time and Money through Chemistry (by Ken Carpenter)

Science.gov (United States)

Hazari, Al

1998-01-01

Useful Chemistry Publishing: Dayton, OH, 1997. 261 pp. Figs. and tables. ISBN: 0965566714. $24.95 (soft cover only). Would you like to learn about the 5 W's of everyday chemistry and chemicals? Who(m) should you see to learn to identify and appraise jewelry? What should you eat for breakfast? When should you get up from your sleep? Where is cholesterol in the human body? Why do pool owners add hydrochloric acid? Then read Save Time and Money through Chemistry, by Ken Carpenter. This book is loaded with practical and useful chemistry information that every person who took chemistry in high school or college wishes he or she had been introduced or exposed to. I know I do.

Keeping agricultural soil out of rivers: evidence of sediment and nutrient accumulation within field wetlands in the UK.

Science.gov (United States)

Ockenden, Mary C; Deasy, Clare; Quinton, John N; Surridge, Ben; Stoate, Chris

2014-03-15

Intensification of agriculture has resulted in increased soil degradation and erosion, with associated pollution of surface waters. Small field wetlands, constructed along runoff pathways, offer one option for slowing down and storing runoff in order to allow more time for sedimentation and for nutrients to be taken up by plants or micro-organisms. This paper describes research to provide quantitative evidence for the effectiveness of small field wetlands in the UK landscape. Ten wetlands were built on four farms in Cumbria and Leicestershire, UK. Annual surveys of sediment and nutrient accumulation in 2010, 2011 and 2012 indicated that most sediment was trapped at a sandy site (70 tonnes over 3 years), compared to a silty site (40 tonnes over 3 years) and a clay site (2 tonnes over 3 years). The timing of rainfall was more important than total annual rainfall for sediment accumulation, with most sediment transported in a few intense rainfall events, especially when these coincided with bare soil or poor crop cover. Nutrient concentration within sediments was inversely related to median particle size, but the total mass of nutrients trapped was dependent on the total mass of sediment trapped. Ratios of nutrient elements in the wetland sediments were consistent between sites, despite different catchment characteristics across the individual wetlands. The nutrient value of sediment collected from the wetlands was similar to that of soil in the surrounding fields; dredged sediment was considered to have value as soil replacement but not as fertiliser. Overall, small field wetlands can make a valuable contribution to keeping soil out of rivers. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Multiple Transceptors for Macro- and Micro-Nutrients Control Diverse Cellular Properties Through the PKA Pathway in Yeast: A Paradigm for the Rapidly Expanding World of Eukaryotic Nutrient Transceptors Up to Those in Human Cells.

Science.gov (United States)

Steyfkens, Fenella; Zhang, Zhiqiang; Van Zeebroeck, Griet; Thevelein, Johan M

2018-01-01

The nutrient composition of the medium has dramatic effects on many cellular properties in the yeast Saccharomyces cerevisiae . In addition to the well-known specific responses to starvation for an essential nutrient, like nitrogen or phosphate, the presence of fermentable sugar or a respirative carbon source leads to predominance of fermentation or respiration, respectively. Fermenting and respiring cells also show strong differences in other properties, like storage carbohydrate levels, general stress tolerance and cellular growth rate. However, the main glucose repression pathway, which controls the switch between respiration and fermentation, is not involved in control of these properties. They are controlled by the protein kinase A (PKA) pathway. Addition of glucose to respiring yeast cells triggers cAMP synthesis, activation of PKA and rapid modification of its targets, like storage carbohydrate levels, general stress tolerance and growth rate. However, starvation of fermenting cells in a glucose medium for any essential macro- or micro-nutrient counteracts this effect, leading to downregulation of PKA and its targets concomitant with growth arrest and entrance into G0. Re-addition of the lacking nutrient triggers rapid activation of the PKA pathway, without involvement of cAMP as second messenger. Investigation of the sensing mechanism has revealed that the specific high-affinity nutrient transporter(s) induced during starvation function as transporter-receptors or transceptors for rapid activation of PKA upon re-addition of the missing substrate. In this way, transceptors have been identified for amino acids, ammonium, phosphate, sulfate, iron, and zinc. We propose a hypothesis for regulation of PKA activity by nutrient transceptors to serve as a conceptual framework for future experimentation. Many properties of transceptors appear to be similar to those of classical receptors and nutrient transceptors may constitute intermediate forms in the development

Multiple Transceptors for Macro- and Micro-Nutrients Control Diverse Cellular Properties Through the PKA Pathway in Yeast: A Paradigm for the Rapidly Expanding World of Eukaryotic Nutrient Transceptors Up to Those in Human Cells

Directory of Open Access Journals (Sweden)

Fenella Steyfkens

2018-03-01

Full Text Available The nutrient composition of the medium has dramatic effects on many cellular properties in the yeast Saccharomyces cerevisiae. In addition to the well-known specific responses to starvation for an essential nutrient, like nitrogen or phosphate, the presence of fermentable sugar or a respirative carbon source leads to predominance of fermentation or respiration, respectively. Fermenting and respiring cells also show strong differences in other properties, like storage carbohydrate levels, general stress tolerance and cellular growth rate. However, the main glucose repression pathway, which controls the switch between respiration and fermentation, is not involved in control of these properties. They are controlled by the protein kinase A (PKA pathway. Addition of glucose to respiring yeast cells triggers cAMP synthesis, activation of PKA and rapid modification of its targets, like storage carbohydrate levels, general stress tolerance and growth rate. However, starvation of fermenting cells in a glucose medium for any essential macro- or micro-nutrient counteracts this effect, leading to downregulation of PKA and its targets concomitant with growth arrest and entrance into G0. Re-addition of the lacking nutrient triggers rapid activation of the PKA pathway, without involvement of cAMP as second messenger. Investigation of the sensing mechanism has revealed that the specific high-affinity nutrient transporter(s induced during starvation function as transporter-receptors or transceptors for rapid activation of PKA upon re-addition of the missing substrate. In this way, transceptors have been identified for amino acids, ammonium, phosphate, sulfate, iron, and zinc. We propose a hypothesis for regulation of PKA activity by nutrient transceptors to serve as a conceptual framework for future experimentation. Many properties of transceptors appear to be similar to those of classical receptors and nutrient transceptors may constitute intermediate forms in

The Urban Watershed as a Transformer of DOM Chemistry

Science.gov (United States)

Gabor, R. S.; Smith, R. M.; Follstad Shah, J.; Kelso, J. E.; Baker, M. A.; Brooks, P. D.

2017-12-01

Growing urban systems stress watersheds, resulting in water quality impacts downstream. Urban stresses can include nutrient runoff from fertilizer, effluent from wastewater treatment plants, and changes in hydrologic routing. Synoptic surveys were performed at two rivers in Salt Lake City, Utah to identify how urbanization drives dissolved organic matter (DOM) chemistry. Red Butte Creek, a small third order stream, flows from a protected mountain environment directly into a highly urbanized mountain area. The organic matter chemistry, as measured by fluorescence, changed dynamics in the urban system, with organic matter demonstrating greater aromaticity and different seasonal patterns than observed in the canyon. Several kilometers downstream of the start of urbanization, the C:N ratio of the organic matter changes from 12.5 to 17.7, at a location where the stream is fed by urban-impacted groundwater, suggesting that subsurface DOC is utilized for microbial respiration in denitrification of urban nitrate inputs. This also corresponds with a shift in the chemistry of the DOM, as measured by fluorescence. Red Butte Creek terminates at the Jordan River, which flows from a highly eutrophic lake and is fed by seven tributaries and five wastewater treatment plants before ending at the Great Salt Lake. The Jordan River is heavily contaminated, with low dissolved oxygen and high nutrient content. The fluorescence index (FI) of DOM in the Jordan River indicates a dominant microbial contribution to the fluorescent organic material, particularly in areas where the dissolved oxygen is low, with the FI becoming less microbial as the DO sag lessens. This corresponds to increasing fluorescence signal in the protein-like area of the fluorescence excitation-emission matrices. Additionally, effluent from four wastewater treatment plants, each with different technologies, had distinct organic matter fluorescence, corresponding with differences in the nitrogen and microbial dynamics

Moving Green Chemistry Forward: Networks as a Foundation

Science.gov (United States)

Carter, T.; Lough, G.

2014-12-01

Green chemistry is a growing discipline, but for a variety of reasons, it has not yet become integrated into science curriculum and the greater societal conscience. With its increasing economic benefits to many sectors including business, industry, and academia and its potential to make science more accessible not only to science students but also to the general citizenry, we suggested answers to the questions: Why has greater success not been realized? What are the particular barriers to wider implementation? And what are incentives and ways to move green chemistry forward? We suggest some strategies and options to both increase the use of green chemistry principles and to also increase stakeholders' understanding of the importance and utility of green chemistry in their daily lives. For example, our main suggestions are that an inclusive, multidisciplinary network would aid in coordinating data and in translating the science into user friendly tools, and that an educational component embedded in this greater effort would also serve to move green chemistry forward.

Educational benefits of green chemistry

Science.gov (United States)

Desmond, Serenity; Ray, Christian; Andino Martínez, José G.

2017-08-01

In this article, we present our current state of affairs in the "greening" of general chemistry laboratories, at the University of Illinois at Urbana-Champaign. We recognize the need to quantify our environmental mark and what we plan to do to continue to strive to make our work more sustainable and educational.

An Integrated Limnology, Microbiology & Chemistry Exercise for Teaching Summer Lake Stratification, Nutrient Consumption & Chemical Thermodynamics

Science.gov (United States)

Dunnivant, Frank M.

2006-01-01

Most chemistry and biology teachers will agree that students have a "disconnect" between these two disciplines. This likely results from the categorization of the topics into two classes or two separate years of study. In this article, the author provides one example of how the two disciplines can be related in an environmental application that…

Patterns in foliar nutrient resorption stoichiometry at multiple scales: controlling factors and ecosystem consequences (Invited)

Science.gov (United States)

Reed, S.; Cleveland, C. C.; Davidson, E. A.; Townsend, A. R.

2013-12-01

During leaf senescence, nutrient rich compounds are transported to other parts of the plant and this 'resorption' recycles nutrients for future growth, reducing losses of potentially limiting nutrients. Variations in leaf chemistry resulting from nutrient resorption also directly affect litter quality, in turn, regulating decomposition rates and soil nutrient availability. Here we investigated stoichiometric patterns of nitrogen (N) and phosphorus (P) resorption efficiency at multiple spatial scales. First, we assembled a global database to explore nutrient resorption among and within biomes and to examine potential relationships between resorption stoichiometry and ecosystem nutrient status. Next, we used a forest regeneration chronosequence in Brazil to assess how resorption stoichiometry linked with a suite of other nutrient cycling measures and with ideas of how nutrient limitation may change over secondary forest regrowth. Finally, we measured N:P resorption ratios of six canopy tree species in a Costa Rican tropical forest. We calculated species-specific resorption ratios and compared them with patterns in leaf litter and topsoil nutrient concentrations. At the global scale, N:P resorption ratios increased with latitude and decreased with mean annual temperature (MAT) and precipitation (MAP; P1 in latitudes >23°. Focusing on tropical sites in our global dataset we found that, despite fewer data and a restricted latitudinal range, a significant relationship between latitude and N:P resorption ratios persisted (PAmazon Basin chronosequence of regenerating forests, where previous work reported a transition from apparent N limitation in younger forests to P limitation in mature forests, we found N resorption was highest in the youngest forest, whereas P resorption was greatest in the mature forest. Over the course of succession, N resorption efficiency leveled off but P resorption continued to increase with forest age. In Costa Rica, though we found species

Visual anticipation biases conscious decision making but not bottom-up visual processing.

Science.gov (United States)

Mathews, Zenon; Cetnarski, Ryszard; Verschure, Paul F M J

2014-01-01

Prediction plays a key role in control of attention but it is not clear which aspects of prediction are most prominent in conscious experience. An evolving view on the brain is that it can be seen as a prediction machine that optimizes its ability to predict states of the world and the self through the top-down propagation of predictions and the bottom-up presentation of prediction errors. There are competing views though on whether prediction or prediction errors dominate the formation of conscious experience. Yet, the dynamic effects of prediction on perception, decision making and consciousness have been difficult to assess and to model. We propose a novel mathematical framework and a psychophysical paradigm that allows us to assess both the hierarchical structuring of perceptual consciousness, its content and the impact of predictions and/or errors on conscious experience, attention and decision-making. Using a displacement detection task combined with reverse correlation, we reveal signatures of the usage of prediction at three different levels of perceptual processing: bottom-up fast saccades, top-down driven slow saccades and consciousnes decisions. Our results suggest that the brain employs multiple parallel mechanism at different levels of perceptual processing in order to shape effective sensory consciousness within a predicted perceptual scene. We further observe that bottom-up sensory and top-down predictive processes can be dissociated through cognitive load. We propose a probabilistic data association model from dynamical systems theory to model the predictive multi-scale bias in perceptual processing that we observe and its role in the formation of conscious experience. We propose that these results support the hypothesis that consciousness provides a time-delayed description of a task that is used to prospectively optimize real time control structures, rather than being engaged in the real-time control of behavior itself.

Nutrient intake and nutrient patterns and risk of lung cancer among heavy smokers: results from the COSMOS screening study with annual low-dose CT

International Nuclear Information System (INIS)

Gnagnarella, Patrizia; Maisonneuve, Patrick; Bellomi, Massimo; Rampinelli, Cristiano; Bertolotti, Raffaella; Spaggiari, Lorenzo; Palli, Domenico; Veronesi, Giulia

2013-01-01

The role of nutrients in lung cancer aetiology remains controversial and has never been evaluated in the context of screening. Our aim was to investigate the role of single nutrients and nutrient patterns in the aetiology of lung cancer in heavy smokers. Asymptomatic heavy smokers (≥20 pack-years) were invited to undergo annual low-dose computed tomography. We assessed diet using a self-administered food frequency questionnaire and collected information on multivitamin supplement use. We performed principal component analysis identifying four nutrient patterns and used Cox proportional Hazards regression to assess the association between nutrients and nutrients patterns and lung cancer risk. During a mean follow-up of 5.7 years, 178 of 4,336 participants were diagnosed with lung cancer by screening. We found a significant risk reduction of lung cancer with increasing vegetable fat consumption (HR for highest vs. lowest quartile = 0.50, 95 % CI = 0.31–0.80; P-trend = 0.02). Participants classified in the high “vitamins and fiber” pattern score had a significant risk reduction of lung cancer (HR = 0.57; 95 % CI = 0.36–0.90, P-trend = 0.01). Among heavy smokers enrolled in a screening trial, high vegetable fat intake and adherence to the “vitamin and fiber” nutrient pattern were associated with reduced lung cancer incidence.

Third Chemistry Conference on Recent Trends in Chemistry

International Nuclear Information System (INIS)

Saeed, M.M.; Wheed, S.

2011-01-01

The third chemistry conference 2011 on recent trends in chemistry was held from October 17-19, 2001 at Islamabad, Pakistan. More than 65 papers and oral presentation. The scope of the conference was wide open and provides and opportunity for participation of broad spectrum of chemists. This forum provided a platform for the dissemination of the latest research followed by discussion pertaining to new trends in chemistry. This con fence covered different aspects of subjects including analytical chemistry, environmental chemistry, polymer chemistry, industrial chemistry, biochemistry and nano chemistry etc. (A.B.)

Radiation chemistry research education in Australia

International Nuclear Information System (INIS)

Sangster, D.F.

1990-01-01

Radiation chemistry techniques may be used to solve research problems in other fields of chemistry and biology particularly when free radicals, excited states or reduction-oxidation reactions are involved. Using pulse radiolysis, absolute kinetic rate constants can be measured. The Australian Institute of Nuclear Science and Engineering is an organization jointly funded by universities, ANSTO and CSIRO. Over the past several years it has provided fares, accommodation and specialized supplementary equipment to enable PhD students and post doctoral fellows to make use of the unique electron beam and gamma irradiation facilities at the Lucas Heights Research Laboratories. It also arranges biennial conferences at which this work is presented and discussed. This talk will discuss the contribution made to the education of students in the undergraduate final year and in physical, metal-organic, organic, polymer and enzyme chemistry research

The Nutrient Density of Snacks: A Comparison of Nutrient Profiles of Popular Snack Foods Using the Nutrient-Rich Foods Index.

Science.gov (United States)

Hess, Julie; Rao, Goutham; Slavin, Joanne

2017-01-01

Background: Although Americans receive almost a quarter of their daily energy from snacks, snacking remains a poorly defined and understood eating occasion. However, there is little dietary guidance about choosing snacks. Families, clinicians, and researchers need a comprehensive approach to assessing their nutritional value. Objective: To quantify and compare the nutrient density of commonly consumed snacks by their overall nutrient profiles using the Nutrient-Rich Foods (NRF) Index 10.3. Methods: NRF Index scores were calculated for the top 3 selling products (based on 2014 market research data) in different snack categories. These NRF scores were averaged to provide an overall nutrient-density score for each category. Results: Based on NRF scores, yogurt (55.3), milk (52.5), and fruit (30.1) emerged as the most nutrient-dense snacks. Ice cream (-4.4), pies and cakes (-11.1), and carbonated soft drinks (-17.2) emerged as the most nutrient-poor snacks. Conclusions: The NRF Index is a useful tool for assessing the overall nutritional value of snacks based on nutrients to limit and nutrients to encourage.

Effects of golf course construction and operation on water chemistry of headwater streams on the Precambrian Shield

International Nuclear Information System (INIS)

Winter, Jennifer G.; Dillon, Peter J.

2005-01-01

To investigate the effects of golf course construction and operation on the water chemistry of Shield streams, we compared the water chemistry in streams draining golf courses under construction (2) and in operation (5) to streams in forested reference locations and to upstream sites where available. Streams were more alkaline and higher in base cation and nitrate concentrations downstream of operational golf courses. Levels of these parameters and total phosphorus increased over time in several streams during golf course construction through to operation. There was evidence of inputs of mercury to streams on two of the operational courses. Nutrient (phosphorus and nitrogen) concentrations were significantly related to the area of unmanaged vegetation in a 30 x 30 m area on either side of the sampling sites, and to River Bank Quality Index scores, suggesting that maintaining vegetated buffers along the stream on golf courses will reduce in-stream nutrient concentrations. - Golf course construction and operation had a significant impact on alkalinity, nitrogen and base cation concentrations of streams

Constitutional dynamic chemistry: bridge from supramolecular chemistry to adaptive chemistry.

Science.gov (United States)

Lehn, Jean-Marie

2012-01-01

Supramolecular chemistry aims at implementing highly complex chemical systems from molecular components held together by non-covalent intermolecular forces and effecting molecular recognition, catalysis and transport processes. A further step consists in the investigation of chemical systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined functional supramolecular architectures by self-assembly from their components, thus behaving as programmed chemical systems. Supramolecular chemistry is intrinsically a dynamic chemistry in view of the lability of the interactions connecting the molecular components of a supramolecular entity and the resulting ability of supramolecular species to exchange their constituents. The same holds for molecular chemistry when the molecular entity contains covalent bonds that may form and break reversibility, so as to allow a continuous change in constitution by reorganization and exchange of building blocks. These features define a Constitutional Dynamic Chemistry (CDC) on both the molecular and supramolecular levels.CDC introduces a paradigm shift with respect to constitutionally static chemistry. The latter relies on design for the generation of a target entity, whereas CDC takes advantage of dynamic diversity to allow variation and selection. The implementation of selection in chemistry introduces a fundamental change in outlook. Whereas self-organization by design strives to achieve full control over the output molecular or supramolecular entity by explicit programming, self-organization with selection operates on dynamic constitutional diversity in response to either internal or external factors to achieve adaptation.The merging of the features: -information and programmability, -dynamics and reversibility, -constitution and structural diversity, points to the emergence of adaptive and evolutive chemistry, towards a chemistry of complex matter.

The isfet in analytical chemistry

NARCIS (Netherlands)

van der Schoot, B.H.; Bergveld, Piet; Bousse, L.J.

1982-01-01

The fast chemical response of the pH-ISFET makes the device an excellent detector in analytical chemistry. The time response of ISFETs, with Al2O3 at the pH-sensitive gate insulator, is determined in a flow injection analysis system. Application of an ISFET and a glass electrode are compared in

Alterações no teores de nutrientes em dois solos alagados, com e sem plantas de arroz Nutrients concentration changes in two flooded soils during the rice cycle

Directory of Open Access Journals (Sweden)

Leandro Souza da Silva

2003-06-01

Full Text Available O alagamento e a presença de plantas alteram as propriedades biológicas e químicas do solo em relação ao ambiente anteriormente oxidado, influenciando a disponibilidade de nutrientes. Foi conduzido um experimento com o objetivo de avaliar as alterações dos teores de alguns nutrientes na solução de um Planossolo e um Gleissolo durante o ciclo do arroz. Os solos foram acondicionados em vasos (50 litros contendo dispositivos para coleta da solução em diferentes profundidades, mantidos sem ou com plantas de arroz. A solução foi coletada aos 10, 19, 44, 77 e 113 dias de alagamento e determinados os teores de P, K, Ca, Mg, Fe e Mn. A concentração dos nutrientes na solução, especialmente o K, variou com a profundidade de coleta e com a presença de plantas, demonstrando a influência desses fatores na disponibilidade dos nutrientes em solos alagados.Flooding a soil and growing plant on it can change its biological and chemistry properties, in comparison with a non-flooded environment. An experiment was conducted in order to study the nutrients dynamics in the solution of two soils (Planossolo and Gleissolo during the rice cycle. Rice plants were cultivated in 50L containers having devices to collect soil solution at several depths (2.5, 5.0, 7.5 and 31cm. In the soil solution, with and without plant, P, K, Ca, Mg, Fe and Mn, were measured at 10, 19, 44, 77, and 113 days after the flooding. Potassium was especially sensible to the rice plant and depth of sampling

Increased nutrient concentrations in Lake Erie tributaries influenced by greenhouse agriculture.

Science.gov (United States)

Maguire, Timothy J; Wellen, Christopher; Stammler, Katie L; Mundle, Scott O C

2018-08-15

Greenhouse production of vegetables is a growing global trade. While greenhouses are typically captured under regulations aimed at farmland, they may also function as a point source of effluent. In this study, the cumulative impacts greenhouse effluents have on riverine macronutrient and trace metal concentrations were examined. Water samples were collected Bi-weekly for five years from 14 rivers in agriculturally dominated watersheds in southwestern Ontario. Nine of the watersheds contained greenhouses with their boundaries. Greenhouse influenced rivers had significantly higher concentrations of macronutrients (nitrogen, phosphorus, and potassium) and trace metals (copper, molybdenum, and zinc). Concentrations within greenhouse influenced rivers appeared to decrease over the 5-year study while concentrations within non-greenhouse influenced river remained constant. The different temporal pattern between river types was attributed to increased precipitation during the study period. Increases in precipitation diluted concentrations in greenhouse influenced rivers; however, non-influenced river runoff proportionally increased nutrient mobility and flow, stabilizing the observed concentrations of non-point sources. Understanding the dynamic nature of environmental releases of point and non-point sources of nutrients and trace metals in mixed agricultural systems using riverine water chemistry is complicated by changes in climatic conditions, highlighting the need for long-term monitoring of nutrients, river flows and weather data in assessing these agricultural sectors. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

An integrated decision support system for wastewater nutrient recovery and recycling to agriculture

Science.gov (United States)

Roy, E. D.; Bomeisl, L.; Cornbrooks, P.; Mo, W.

2017-12-01

Nutrient recovery and recycling has become a key research topic within the wastewater engineering and nutrient management communities. Several technologies now exist that can effectively capture nutrients from wastewater, and innovation in this area continues to be an important research pursuit. However, practical nutrient recycling solutions require more than capable nutrient capture technologies. We also need to understand the role that wastewater nutrient recovery and recycling can play within broader nutrient management schemes at the landscape level, including important interactions at the nexus of food, energy, and water. We are developing an integrated decision support system that combines wastewater treatment data, agricultural data, spatial nutrient balance modeling, life cycle assessment, stakeholder knowledge, and multi-criteria decision making. Our goals are to: (1) help guide design decisions related to the implementation of sustainable nutrient recovery technology, (2) support innovations in watershed nutrient management that operate at the interface of the built environment and agriculture, and (3) aid efforts to protect aquatic ecosystems while supporting human welfare in a circular nutrient economy. These goals will be realized partly through the assessment of plausible alternative scenarios for the future. In this presentation, we will describe the tool and focus on nutrient balance results for the New England region. These results illustrate that both centralized and decentralized wastewater nutrient recovery schemes have potential to transform nutrient flows in many New England watersheds, diverting wastewater N and P away from aquatic ecosystems and toward local or regional agricultural soils where they can offset a substantial percentage of imported fertilizer. We will also highlight feasibility criteria and next steps to integrate stakeholder knowledge, economics, and life cycle assessment into the tool.

Radiation chemistry

International Nuclear Information System (INIS)

Rodgers, F.; Rodgers, M.A.

1987-01-01

The contents of this book include: Interaction of ionizing radiation with matter; Primary products in radiation chemistry; Theoretical aspects of radiation chemistry; Theories of the solvated electron; The radiation chemistry of gases; Radiation chemistry of colloidal aggregates; Radiation chemistry of the alkali halides; Radiation chemistry of polymers; Radiation chemistry of biopolymers; Radiation processing and sterilization; and Compound index

Uptake of macro- and micro-nutrients into leaf, woody, and root tissue of Populus after irrigation with landfill leachate

Science.gov (United States)

Jill A. Zalesny; Ronald S., Jr. Zalesny; Adam H. Wiese; Bart T. Sexton; Richard B. Hall

2008-01-01

Information about macro- and micro-nutrient uptake and distribution into tissues of Populus irrigated with landfill leachate helps to maximize biomass production and understand impacts of leachate chemistry on tree health. We irrigated eight Populus clones (NC 13460, NCI4O18, NC14104, NC14106, DM115, DN5, NM2, NM6) with fertilized (N, P, K) well...

Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia

International Nuclear Information System (INIS)

Wulp, Simon A. van der; Damar, Ario; Ladwig, Norbert; Hesse, Karl-J.

2016-01-01

The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377 m 3 s −1 entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174 tons and 14 to 60 tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics. - Highlights: • Full overview of river discharges, nutrient flux and nutrient levels in Jakarta Bay • Important overview of nutrient flux from individual rivers • Simulations identify the principal drivers of water circulation and nutrient gradient. • Nutrient dispersion model includes the local effects of the Java Sea current system.

Approaches and uncertainties in nutrient budgets; Implications for nutrient management and environmental policies

NARCIS (Netherlands)

Oenema, O.; Kros, J.; Vries, de W.

2003-01-01

Nutrient budgets of agroecosystems are constructed either (i) to increase the understanding of nutrient cycling, (ii) as performance indicator and awareness raiser in nutrient management and environmental policy, or (iii) as regulating policy instrument to enforce a certain nutrient management

Bend It, Stretch It, Hammer It, Break It: Materials Chemistry Applied

Science.gov (United States)

Neff, Grace A.; Retsek, Jennifer; Berber-Jimenez, Lola; Barber, Nicole; Coles, Monica; Fintikakis, Christina; Huigens, Brent

2010-01-01

Making chemistry both accessible and interesting to middle and high school students can be difficult. Convincing middle and high school teachers that they will learn something new and applicable from a professional development workshop in chemistry can be equally challenging. This paper describes the use of material science as a means to enhance…

Global comparison reveals biogenic weathering as driven by nutrient limitation at ecosystem scale

Science.gov (United States)

Boy, Jens; Godoy, Roberto; Dechene, Annika; Shibistova, Olga; Amir, Hamid; Iskandar, Issi; Fogliano, Bruno; Boy, Diana; McCulloch, Robert; Andrino, Alberto; Gschwendtner, Silvia; Marin, Cesar; Sauheitl, Leopold; Dultz, Stefan; Mikutta, Robert; Guggenberger, Georg

2017-04-01

A substantial contribution of biogenic weathering in ecosystem nutrition, especially by symbiotic microorganisms, has often been proposed, but large-scale in vivo studies are still missing. Here we compare a set of ecosystems spanning from the Antarctic to tropical forests for their potential biogenic weathering and its drivers. To address biogenic weathering rates, we installed mineral mesocosms only accessible for bacteria and fungi for up to 4 years, which contained freshly broken and defined nutrient-baring minerals in soil A horizons of ecosystems along a gradient of soil development differing in climate and plant species communities. Alterations of the buried minerals were analyzed by grid-intersection, confocal lascer scanning microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy on the surface and on thin sections. On selected sites, carbon fluxes were tracked by 13C labeling, and microbial community was identified by DNA sequencing. In young ecosystems (protosoils) biogenic weathering is almost absent and starts after first carbon accumulation by aeolian (later litter) inputs and is mainly performed by bacteria. With ongoing soil development and appearance of symbiotic (mycorrhized) plants, nutrient availability in soil increasingly drove biogenic weathering, and fungi became the far more important players than bacteria. We found a close relation between fungal biogenic weathering and available potassium across all 16 forested sites in the study, regardless of the dominant mycorrhiza type (AM or EM), climate, and plant-species composition. We conclude that nutrient limitations at ecosystem scale are generally counteracted by adapted fungal biogenic weathering. The close relation between fungal weathering and plant-available nutrients over a large range of severely contrasting ecosystems points towards a direct energetic support of these weathering processes by the photoautotrophic community, making biogenic weathering a

Box Model of Freshwater, Salinity and Nutrient in the Delta Mahakam, East Kalimantan

Directory of Open Access Journals (Sweden)

Marojahan Simanjuntak

2011-04-01

Full Text Available Box Model of Freshwater, Salinity and Nutrient in the Delta Mahakam, East Kalimantan. Research has been conducted in the southern part of the Mahakam Delta, East Kalimantan. Method of measuring temperature, salinity, light transmission and turbidity by using CTD model 603 SBE and current measurement and bathymetry by using ADCP model RDI. Measurement parameters on the nutrient chemistry are based of water samples taken using Nansen bottles from two depths. The purpose of this study to determine the mechanism of freshwater, salinity and nutrient transport from the land of the Mahakam River which interact with seawater by using box models. The results illustrate that the vertical distribution of salinity in the Mahakam Delta has obtained a high stratification, where the freshwater salinity 12.30 psu at the surface of a river flowing toward the sea, and seawater of high salinity 30.07 psu flowing in the direction river under the surface that are separated by a layer of mixture. Freshwater budget of the sea (VSurf obtained for 0,0306 x 109 m3 day-1, and the sea water salinity budget is going into the bottom layer system (VDeep.SOcn-d obtained for 20,727 x 109 psu day-1. While time dilution (Syst obtained for 0.245 day-1 or 5.87 hours. Nutrient budget in the surface layer obtained by the system is autotrophic while in layers near the bottom tend to be heterotrophic

Theoretical chemistry periodicities in chemistry and biology

CERN Document Server

Eyring, Henry

1978-01-01

Theoretical Chemistry: Periodicities in Chemistry and Biology, Volume 4 covers the aspects of theoretical chemistry. The book discusses the stably rotating patterns of reaction and diffusion; the chemistry of inorganic systems exhibiting nonmonotonic behavior; and population cycles. The text also describes the mathematical modeling of excitable media in neurobiology and chemistry; oscillating enzyme reactions; and oscillatory properties and excitability of the heart cell membrane. Selected topics from the theory of physico-chemical instabilities are also encompassed. Chemists, mechanical engin

Organic amendments and nutrient leaching in soil columns

Science.gov (United States)

The lack of nutrient build up in reclaimed coal mine soils would therefore require additional inputs to maintain plant productivity and establishment of a healthy ecosystem. In a greenhouse experiment, reclaimed coal mine soil were amended with fresh and composted poultry manure at the rates based ...

Characterisation of the inorganic chemistry of surface waters in ...

African Journals Online (AJOL)

The main purpose of this study was to determine a simple inorganic chemistry index that can be used for all surface waters in South Africa, in order to characterise the inorganic chemistry of surface waters. Water quality data collected up until 1999 from all sample monitoring stations (2 068 monitoring stations, 364 659 ...

Modeling farm nutrient flows in the North China Plain to reduce nutrient losses

NARCIS (Netherlands)

Zhao, Zhanqing; Bai, Zhaohai; Wei, Sha; Ma, Wenqi; Wang, Mengru; Kroeze, Carolien; Ma, Lin

2017-01-01

Years of poor nutrient management practices in the agriculture industry in the North China Plain have led to large losses of nutrients to the environment, causing severe ecological consequences. Analyzing farm nutrient flows is urgently needed in order to reduce nutrient losses. A farm-level

Recent progress in plant nutrition research: cross-talk between nutrients, plant physiology and soil microorganisms.

Science.gov (United States)

Ohkama-Ohtsu, Naoko; Wasaki, Jun

2010-08-01

Mineral nutrients taken up from the soil become incorporated into a variety of important compounds with structural and physiological roles in plants. We summarize how plant nutrients are linked to many metabolic pathways, plant hormones and other biological processes. We also focus on nutrient uptake, describing plant-microbe interactions, plant exudates, root architecture, transporters and their applications. Plants need to survive in soils with mineral concentrations that vary widely. Describing the relationships between nutrients and biological processes will enable us to understand the molecular basis for signaling, physiological damage and responses to mineral stresses.

Chemistry for sustainable development in Africa

Energy Technology Data Exchange (ETDEWEB)

Gurib-Fakim, Ameenah [Mauritius Univ., Reduit (Mauritius); Eloff, Jacobus Nicolaas (eds.) [Pretoria Univ. (South Africa). Faculty of Veterinary Science

2013-07-01

Chemistry for Sustainable Development in Africa' gives an insight into current Chemical research in Africa. It is edited and written by distinguished African scientists and includes contributions from Chemists from Northern, Southern, Western, Eastern, Central and Island state African Countries. The core themes embrace the most pressing issues of our time, including Environmental Chemistry, Renewable Energies, Health and Human Well-Being, Food and Nutrition, and Bioprospecting and Commercial Development. This book is invaluable for teaching and research institutes in Africa and worldwide, private sector entities dealing with natural products from Africa, as well as policy and decision-making bodies and non-governmental organizations.

Unusual Amino Acids in Medicinal Chemistry.

Science.gov (United States)

Blaskovich, Mark A T

2016-12-22

Unusual amino acids are fundamental building blocks of modern medicinal chemistry. The combination of readily functionalized amine and carboxyl groups attached to a chiral central core along with one or two potentially diverse side chains provides a unique three-dimensional structure with a high degree of functionality. This makes them invaluable as starting materials for syntheses of complex molecules, highly diverse elements for SAR campaigns, integral components of peptidomimetic drugs, and potential drugs on their own. This Perspective highlights the diversity of unnatural amino acid structures found in hit-to-lead and lead optimization campaigns and clinical stage and approved drugs, reflecting their increasingly important role in medicinal chemistry.

Impact of managed moorland burning on peat nutrient and base cation status

Science.gov (United States)

Palmer, Sheila; Gilpin, Martin; Wearing, Catherine; Johnston, Kerrylyn; Holden, Joseph; Brown, Lee

2013-04-01

Controlled 'patch' burning of moorland vegetation has been used for decades in the UK to stimulate growth of heather (Calluna vulgaris) for game bird habitat and livestock grazing. Typically small patches (300-900 m2) are burned in rotations of 8-25 years. However, our understanding of the short-to-medium term environmental impacts of the practice on these sensitive upland areas has so far been limited by a lack of scientific data. In particular the effect of burning on concentrations of base cations and acid-base status of these highly organic soils has implications both for ecosystem nutrient status and for buffering of acidic waters. As part of the EMBER project peat chemistry data were collected in ten upland blanket peat catchments in the UK. Five catchments were subject to a history of prescribed rotational patch burning. The other five catchments acted as controls which were not subject to burning, nor confounded by other detrimental activities such as drainage or forestry. Soil solution chemistry was also monitored at two intensively studied sites (one regularly burned and one control). Fifty-centimetre soil cores, sectioned into 5-cm intervals, were collected from triplicate patches of four burn ages at each burned site, and from twelve locations at similar hillslope positions at each control site. At the two intensively monitored sites, soil solution chemistry was monitored at four depths in each patch. Across all sites, burned plots had significantly smaller cation exchange capacities, lower concentrations of exchangeable base cations and increased concentrations of exchangeable H+ and Al3+ in near-surface soil. C/N ratios were also lower in burned compared to unburned surface soils. There was no consistent trend between burn age and peat chemistry across all burned sites, possibly reflecting local controls on post-burn recovery rates or external influences on burn management decisions. At the intensively monitored site, plots burned less than two years

Microbial enzyme activity, nutrient uptake and nutrient limitation in forested streams

Science.gov (United States)

Brian H. Hill; Frank H. McCormick; Bret C. Harvey; Sherri L. Johnson; Melvin L. Warren; Colleen M. Elonen

2010-01-01

The flow of organic matter and nutrients from catchments into the streams draining them and the biogeochemical transformations of organic matter and nutrients along flow paths are fundamental processes instreams (Hynes,1975; Fisher, Sponseller & Heffernan, 2004). Microbial biofilms are often the primary interface for organic matter and nutrient uptake and...

E Pluribus Tres: The 2009 Nobel Prize in Chemistry

OpenAIRE

Carter Jr., Charles W.

2009-01-01

This year’s Nobel Prize in Chemistry celebrates a multitude of research areas, making the difficult selection of those most responsible for providing atomic details of the nanomachine that makes proteins according to genetic instructions. The Ribosome and RNA polymerase (recognized in 2006) structures highlight a puzzling asymmetry at the origins of biology.

Some aspects of nutrient chemistry of the Caribbean Sea

Digital Repository Service at National Institute of Oceanography (India)

Rajendran, A; DileepKumar, M.; Khan, A.A; Knight, D.; O'Reilly, A; Yen, I.C.; Wagh, A; Desai, B.N.

waters showed a decrease up to 110 mu mol.dm sup(-3) at around 400 m. Within the euphotic zone considerable amounts of oxygen (30-60 mu mol.dm sup(-3)) were utilized for organic matter degradation, even within the euphotic zone. Two nitrate maxima, one...

Investigating the Effect of Livestock Grazing and Associated Plant Community Shifts on Carbon and Nutrient Cycling in Alberta, Canada

Science.gov (United States)

Hewins, D. B.; Chuan, S.; Stolnikova, E.; Bork, E. W.; Carlyle, C. N.; Chang, S. X.

2015-12-01

Grassland ecosystems are ubiquitous across the globe covering an estimated 40 % of Earth's terrestrial landmass. These ecosystems are widely valued for providing forage for domestic livestock and a suite of important ecosystem goods and services including carbon (C) storage. Despite storing more than 30 % of soil C globally, the effect of both livestock grazing and the associated change in plant community structure in response to grazing on C and nutrient cycling remains uncertain. To gain a quantitative understanding of the direct and indirect effects of livestock grazing on C and nutrient cycling, we established study sites at 15 existing site localities with paired long-term grazing (ca. 30 y) and non-grazed treatments (totaling 30 unique plant communities). Our sites were distributed widely across Alberta in three distinct grassland bioclimatic zones allowing us to make comparisons across the broad range of climate variability typical of western Canadian grasslands. In each plant community we decomposed 5 common plant species that are known to increase or decrease in response to grazing pressure, a unique plant community sample, and a cellulose paper control. We measured mass loss, initial lignin, C and N concentrations at 0, 1, 3, 6 and 12 months of field incubation. In addition we assayed hydrolytic and oxidative extracellular enzymes associated with for C (n= 5 hydrolytic; phenoloxidase and peroxidase) and nutrients (i.e. N and P; n=1 ea.) cycling from each litter sample at each collection. Our results suggest that by changing the plant community structure, grazing can affect rates of decomposition and associated biogeochemical cycling by changing plant species and associated litter inputs. Moreover, measures of microbial function are controlled by site-specific conditions (e.g. temperature and precipitation), litter chemistry over the course of our incubation.

Presidential Green Chemistry Challenge: 2002 Greener Reaction Conditions Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2002 award winner, Cargill Dow, developed the NatureWorks process to make biobased, compostable, and recyclable polylactic acid polymers for fibers and plastic packaging.

Mediating Education Policy: Making up the "Anti-Politics" of Third-Sector Participation in Public Education

Science.gov (United States)

Williamson, Ben

2014-01-01

This article examines the participation of "third-sector" organisations in public education in England. These organisations act as a cross-sectoral policy network made up of new kinds of policy experts: mediators and brokers with entrepreneurial careers in ideas. They have sought to make education reform thinkable, intelligible and…

Presidential Green Chemistry Challenge: 2014 Small Business Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2014 award winner, Amyris, engineered yeast to make a chemical called farnesene, which is a building block hydrocarbon that can be converted into a renewable, drop-in replacement for petroleum diesel.

Complex chemistry

International Nuclear Information System (INIS)

Kim, Bong Gon; Kim, Jae Sang; Kim, Jin Eun; Lee, Boo Yeon

2006-06-01

This book introduces complex chemistry with ten chapters, which include development of complex chemistry on history coordination theory and Warner's coordination theory and new development of complex chemistry, nomenclature on complex with conception and define, chemical formula on coordination compound, symbol of stereochemistry, stereo structure and isomerism, electron structure and bond theory on complex, structure of complex like NMR and XAFS, balance and reaction on solution, an organo-metallic chemistry, biology inorganic chemistry, material chemistry of complex, design of complex and calculation chemistry.

A New Approach To Soil Sampling For Risk Assessment Of Nutrient Mobilisation.

Science.gov (United States)

Jonczyk, J. C.; Owen, G. J.; Snell, M. A.; Barber, N.; Benskin, C.; Reaney, S. M.; Haygarth, P.; Quinn, P. F.; Barker, P. A.; Aftab, A.; Burke, S.; Cleasby, W.; Surridge, B.; Perks, M. T.

2016-12-01

Traditionally, risks of nutrient and sediment losses from soils are assessed through a combination of field soil nutrient values on soil samples taken over the whole field and the proximity of the field to water courses. The field average nutrient concentration of the soil is used by farmers to determine fertiliser needs. These data are often used by scientists to assess the risk of nutrient losses to water course, though are not really `fit' for this purpose. The Eden Demonstration Test Catchment (http://www.edendtc.org.uk/) is a research project based in the River Eden catchment, NW UK, with the aim of cost effectively mitigating diffuse pollution from agriculture whilst maintaining agricultural productivity. Three instrumented focus catchments have been monitored since 2011, providing high resolution in-stream chemistry and ecological data, alongside some spatial data on soils, land use and nutrient inputs. An approach to mitigation was demonstrated in a small sub-catchment, where surface runoff was identified as the key drivers of nutrient losses, using a suite of runoff attenuation features. Other issues identified were management of hard- standings and soil compaction. A new approach for evaluating nutrient losses from soils is assessed in the Eden DTC project. The Sensitive Catchment Integrated Modelling and Prediction (SCIMAP) model is a risk-mapping framework designed to identify where in the landscape diffuse pollution is most likely to be originating (http://www.scimap.org.uk) and was used to look at the spatial pattern of erosion potential. The aim of this work was to assess if erosion potential identified through the model could be used to inform a new soil sampling strategy, to better assess risk of erosion and risk of transport of sediment-bound phosphorus. Soil samples were taken from areas with different erosion potential. The chemical analysis of these targeted samples are compared to those obtained using more traditional sampling approaches

Cost-effective nutrient sources for tissue culture of cassava ( Manihot ...

African Journals Online (AJOL)

Application of tissue culture technology is constrained by high costs making seedlings unaffordable. The objective of this study was to evaluate the possibility of using locally available fertilizers as alternative nutrient sources for cassava micropropagation. A Low Cost Medium (LCM) whereby the conventional sources of four ...

Soil Chemical Weathering and Nutrient Budgets along an Earthworm Invasion Chronosequence in a Northern Minnesota Forest

Science.gov (United States)

Resner, K. E.; Yoo, K.; Sebestyen, S. D.; Aufdenkampe, A. K.; Lyttle, A.; Weinman, B. A.; Blum, A.; Hale, C. M.

2011-12-01

We are investigating the impact of exotic earthworms on the rate of nutrient and ion release from soil chemical weathering along an ~200 m invasion chronosequence in a northern Minnesota sugar maple forest. The earthworms belong to three ecological groups that represent different feeding and burrowing behaviors, all of which were introduced from Europe to the previously earthworm-free Great Lakes Region through fishing and agricultural activities. As earthworms digest and mix the soil, we hypothesize that they significantly alter chemical weathering processes by incorporating mineral surfaces to new geochemical environments in their intestines and at different soil depths. The effect of mixing on soil morphology is dramatic, but biogeochemical changes remain largely unknown and therefore are poorly coupled to the current and potential changes in forest ecosystems under the threat of exotic earthworms. We analyze the activities of short-lived isotopes 137-Cs and 210-Pb along with the inorganic chemistry of soil, water, and leaf litter across an invasion transect and link these measurements to the biomass and species composition of exotic earthworms. Earthworms vertically relocate minerals and organic matter largely within the top ~10 cm, which is reflected in the depth profiles of the short-lived isotopes. Among the inorganic nutrients analyzed, Ca is of particular interest due to sugar maple's aptitude for recycling Ca. Fractional mass loss values (tau) of Ca, relative to the soil's parent material, show an enrichment factor of 14 in the least invaded A horizon soils. However, such a high enrichment factor declines dramatically in the heavily invaded soils, suggesting that earthworm activities contribute to leaching Ca. In contrast, the enrichment factor of Fe increases with greater degrees of earthworm invasion, which is consistent with the extraction chemistry data showing greater quantities of pedogenic crystalline iron oxides and greater mineral specific

Development of Database and Lecture Book for Nuclear Water Chemistry

International Nuclear Information System (INIS)

Maeng, Wan Young; Kim, U. C.; Na, J. W.; Choi, B. S.; Lee, E. H.; Kim, K. H.; Kim, K. M.; Kim, S. H.; Im, K. S.

2010-02-01

In order to establish a systematic and synthetic knowledge system of nuclear water chemistry, we held nuclear water chemistry experts group meetings. We discussed the way of buildup and propagation of nuclear water chemistry knowledge with domestic experts. We obtained a lot of various opinions that made the good use of this research project. The results will be applied to continuous buildup of domestic nuclear water chemistry knowledge database. Lessons in water chemistry of nuclear power plants (NPPs) have been opened in Nuclear Training and education Center, KAERI to educate the new generation who are working and will be working at the department of water chemistry of NPPs. The lessons were 17 and lesson period was from 12th May through 5th November. In order to progress the programs, many water chemistry experts were invited. They gave lectures to the younger generation once a week for 2 h about their experiences obtained during working on water chemistry of NPPs. The number of attendance was 290. The lessons were very effective and the lesson data will be used to make database for continuous use

Maximizing the Adjacent Possible in Automata Chemistries.

Science.gov (United States)

Hickinbotham, Simon; Clark, Edward; Nellis, Adam; Stepney, Susan; Clarke, Tim; Young, Peter

2016-01-01

Automata chemistries are good vehicles for experimentation in open-ended evolution, but they are by necessity complex systems whose low-level properties require careful design. To aid the process of designing automata chemistries, we develop an abstract model that classifies the features of a chemistry from a physical (bottom up) perspective and from a biological (top down) perspective. There are two levels: things that can evolve, and things that cannot. We equate the evolving level with biology and the non-evolving level with physics. We design our initial organisms in the biology, so they can evolve. We design the physics to facilitate evolvable biologies. This architecture leads to a set of design principles that should be observed when creating an instantiation of the architecture. These principles are Everything Evolves, Everything's Soft, and Everything Dies. To evaluate these ideas, we present experiments in the recently developed Stringmol automata chemistry. We examine the properties of Stringmol with respect to the principles, and so demonstrate the usefulness of the principles in designing automata chemistries.

My search for carbocations and their role in chemistry

International Nuclear Information System (INIS)

Olah, George Andrew

1995-01-01

Hydrocarbons are compounds of the elements carbon and hydrogen. They make up natural gas and oil thus is essential for our modern life. Burning of hydrocarbons is used to generate energy in our power plants and heat our homes. Derived gasoline and diesel oil propel our cars, trucks, and airplanes. Hydrocarbons are also the feedstock for practically every man-made material from plastic to pharmaceuticals. What nature is giving us needs, however, to be processed and modified. We will eventually also need to make hydrocarbons ourselves, as our natural resources are depleted. Many of the used processes are acid catalyzed involving chemical reactions proceeding through positive ion intermediates. Consequently, the knowledge of these intermediates and their chemistry is of substantial significance both as fundamental, as well as practical science. Carbocations are the positive ions of carbon compounds. It was in 1901 that Norris and Kehrman independently discovered that colorless triphenylmethyl alcohol gave deep yellow solutions in concentrated sulfuric acid. Triphenylmethyl chloride similarly formed orange complexes with aluminum and tin chlorides

Can Biochar Covers Reduce Emissions from Manure Lagoons While Capturing Nutrients?

Science.gov (United States)

The unique physical and chemical properties of biochars make them promising materials for odor, gas, and nutrient sorption. Floating covers made from organic materials (biocovers) are one option for reducing odor and gas emissions from livestock manure lagoons. This study evaluat...

Potential of diatom consortium developed by nutrient enrichment for biodiesel production and simultaneous nutrient removal from waste water

Directory of Open Access Journals (Sweden)

Thomas Kiran Marella

2018-05-01

Full Text Available Because of the decreasing fossil fuel supply and increasing greenhouse gas (GHG emissions, microalgae have been identified as a viable and sustainable feedstock for biofuel production. The major effect of the release of wastewater rich in organic compounds has led to the eutrophication of freshwater ecosystems. A combined approach of freshwater diatom cultivation with urban sewage water treatment is a promising solution for nutrient removal and biofuel production. In this study, urban wastewater from eutrophic Hussain Sagar Lake was used to cultivate a diatom algae consortium, and the effects of silica and trace metal enrichment on growth, nutrient removal, and lipid production were evaluated. The nano-silica-based micronutrient mixture Nualgi containing Si, Fe, and metal ions was used to optimize diatom growth. Respectively, N and P reductions of 95.1% and 88.9%, COD and BOD reductions of 91% and 51% with a biomass yield of 122.5 mg L−1 day−1 and lipid productivity of 37 mg L−1 day−1 were observed for cultures grown in waste water using Nualgi. Fatty acid profiles revealed 13 different fatty acids with slight differences in their percentage of dry cell weight (DCW depending on enrichment level. These results demonstrate the potential of diatom algae grown in wastewater to produce feedstock for renewable biodiesel production. Enhanced carbon and excess nutrient utilization makes diatoms ideal candidates for co-processes such as CO2 sequestration, biodiesel production, and wastewater phycoremediation. Keywords: Micro algae, Diatom, Biodiesel, Nualgi, Nutrient removal, Wastewater

A deeper insight into the ethnic make-up of school cohorts: diversity and school achievement

NARCIS (Netherlands)

Maestri, V.

2011-01-01

While the share of non-native students in a class is expected to have a non positive effect on school achievement, little is said about the heterogeneity of the ethnic minority make-up. Ethnic diversity can stimulate the creativity of students, can push them to be proficient in the instructional

River Metabolism and Nutrient Cycling at the Point Scale: Insights from In Situ Sensors in Benthic Chambers

Science.gov (United States)

Cohen, M. J.; Reijo, C. J.; Hensley, R. T.

2017-12-01

Riverine processing of nutrients and carbon is a local process, subject to heterogeneity in sediment, biotic, insolation, and flow velocity drivers. Measurements at the reach scale aggregate across riverscapes, limiting their utility for enumerating these drivers, and thus for scaling to river networks. Using a combination of in situ sensors that sample water chemistry at high temporal resolution and open benthic chambers that isolate the biogeochemical impacts of a small footprint of benthic surface area, we explored controls on metabolism and nutrient cycling. We specifically sought to answer two questions. First, what are the controls on primary production, with a particular emphasis on the relative roles of light vs. nutrient limitation? Second, what are the pathways of nutrient retention, and do the reaction kinetics of these different pathways differ? We demonstrate the considerable utility of these benthic chambers, reasoning that they provide experimental units for river processes that are not attainable at the reach or network scale. Specifically, in addition to their ability to sample the heterogeneity of the river bed as well as observe nutrient depletion to create concentrations well below ambient levels, they enable manipulative experiments (e.g., nutrient enrichment, light reduction, grazer adjustments) while retaining key elements of the natural system. Across several of Florida's spring-fed river sites, our results strongly support the primacy of light limitation of primary production, with very little evidence of any incremental effects of nutrient enrichment. Nutrient depletion assays further support the dominance of two N retention mechanisms (denitrification and assimilation), the kinetics of which differ markedly, with denitrification exhibiting nearly first-order reactions, and assimilation following zero-order or Michaelis-Menten kinetics over the range of observed concentrations. This latter result helps explain the absence of strong

Trichoderma Biofertilizer Links to Altered Soil Chemistry, Altered Microbial Communities, and Improved Grassland Biomass

Directory of Open Access Journals (Sweden)

Fengge Zhang

2018-04-01

Full Text Available In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly (p = 0.019 increased following amendment with 9,000 kg ha−1 of Trichoderma biofertilizer (composted cattle manure + inoculum compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha−1 biofertilizer. This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha−1 increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella. Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella. According to our structural equation modeling (SEM, Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma

Trichoderma Biofertilizer Links to Altered Soil Chemistry, Altered Microbial Communities, and Improved Grassland Biomass.

Science.gov (United States)

Zhang, Fengge; Huo, Yunqian; Cobb, Adam B; Luo, Gongwen; Zhou, Jiqiong; Yang, Gaowen; Wilson, Gail W T; Zhang, Yingjun

2018-01-01

In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly ( p = 0.019) increased following amendment with 9,000 kg ha -1 of Trichoderma biofertilizer (composted cattle manure + inoculum) compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha -1 biofertilizer). This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS) revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha -1 ) increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella . Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella . According to our structural equation modeling (SEM), Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma

Impact of wildfire on stream nutrient chemistry and ecosystem metabolism in boreal forest catchments of interior Alaska

Science.gov (United States)

Emma F. Betts; Jeremy B. Jones

2009-01-01

With climatic warming, wildfire occurrence is increasing in the boreal forest of interior Alaska. Loss of catchment vegetation during fire can impact streams directly through altered solute and debris inputs and changed light and temperature regimes. Over longer time scales, fire can accelerate permafrost degradation, altering catchment hydrology and stream nutrient...

Chemistry without borders: An overview

Science.gov (United States)

As chemistry becomes more globalized, it is important for an organization to be interconnected and adaptable, and for an individual to keep up with changes and latest scientific findings and keep options open. Many of the challenges and the opportunities of globalization are in the areas of jobs, re...

Presidential Green Chemistry Challenge: 1997 Greener Synthetic Pathways Award

Science.gov (United States)

Presidential Green Chemistry Challenge 1997 award winner, BHC Company, developed a highly atom-efficient method to make ibuprofen, a common painkiller, using three catalytic steps instead of six stoichiometric ones.

Presidential Green Chemistry Challenge: 2009 Greener Synthetic Pathways Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2009 award winner, Eastman Chemical Co., makes esters for emollients and emulsifiers in cosmetics with immobilized enzymes, saving energy and avoiding strong acids and organic solvents.

Presidential Green Chemistry Challenge: 1999 Greener Reaction Conditions Award

Science.gov (United States)

Presidential Green Chemistry Challenge 1999 award winner, Nalco Chemical Co., developed homogeneous dispersion polymerization with water as the solvent to make polymers to treat water in industrial and municipal operations.

An avian equivalent of make-up?

NARCIS (Netherlands)

Piersma, T; Dekker, M; Damste, JSS; Sinninghe Damsté, Jaap S.; Lambrechts, M.

We report that a long-distance migrating shorebird, the red knot, makes a complete switch from commonly occurring monoester preen waxes to a much rarer class of higher-molecular-weight diester waxes at the time of take-off to the high arctic breeding grounds. The cold arctic climate would have

Estimating nutrient releases from agriculture in China: An extended substance flow analysis framework and a modeling tool

International Nuclear Information System (INIS)

Chen, M.; Chen, J.; Sun, F.

2010-01-01

Agriculture related pollution has attracted the attention of policy makers as well as scientists in China as its contribution to water impairment has increased, and quantitative information at the national and regional levels is being sought to support decision making. However, traditional approaches are either time-consuming, expensive (e.g. national surveys) or oversimplified and crude (e.g. coefficient methods). Therefore, this study proposed an extended substance flow analysis (SFA) framework to estimate nutrient releases from agricultural and rural activities in China by depicting the nutrient flows in Chinese agro-ecosystems. The six-step process proposed herein includes: (a) system definition; (b) model development; (c) database development; (d) model validation; (e) results interpretation; and (f) uncertainty analysis. The developed Eubolism (Elementary Unit based nutrient Balance mOdeLIng in agro-ecoSysteM) model combined a nutrient balance module with an emission inventory module to quantify the nutrient flows in the agro-ecosystem. The model was validated and then applied to estimate the total agricultural nutrient loads, identify the contribution of different agricultural and rural activities and different land use types to the total loads, and analyze the spatial pattern of agricultural nutrient emissions in China. These results could provide an entire picture of agricultural pollution at the national level and be used to support policy making. Furthermore, uncertainties associated with the structure of the elementary units, spatial resolution, and inputs/parameters were also analyzed to evaluate the robustness of the model results.

Aquatic chemistry of flood events

Science.gov (United States)

Klavins, Maris; Rodinov, Valery

2015-04-01

During flood events a major discharge of water and dissolved substances happens. However flood waters very much differs from water composition during low-water events. Aquatic chemistry of flood waters also is of importance at the calculation of loadings as well as they might have major impact on water quality in receiving water bodies (lakes, coastal waters and seas). Further flood regime of rivers is subjected to changes due to climate change and growing impact of human activities. The aim of this study is to analyse water chemical composition changes during flood events in respect to low water periods, character of high-water events and characteristics of the corresponding basin. Within this study, the concentrations of major dissolved substances in the major rivers of Latvia have been studied using monitoring data as well as field studies during high water/ low water events. As territories of studies flows of substances in river basins/subbasins with different land-use character and different anthropogenic impacts has been studied to calculate export values depending on the land-use character. Impact of relations between dissolved substances and relations in respect to budgets has been calculated. The dynamics of DOC, nutrient and major dissolved substance flows depending on landuse pattern and soil properties in Latvia has been described, including emissions by industrial and agricultural production. In these changes evidently climate change signals can be identified. The water chemistry of a large number of rivers during flood events has been determined and the possible impact of water chemical composition on DOC and nutrient flows has been evaluated. Long-term changes (1977-2013) of concentrations of dissolved substances do not follow linear trends but rather show oscillating patterns, indicating impact of natural factors, e.g. changing hydrological and climatic conditions. There is a positive correlation between content of inert dissolved substances and

Bracing system of the reflecting sheets making up an insulating pile

International Nuclear Information System (INIS)

Carr, R.W.

1976-01-01

In order to reduce heat and radiation losses, the body of nuclear reactors and the connected pipe work are encased in reflecting and insulating piles of thin spaced sheets of aluminium or stainless steel. These spaced sheets are then encased in thicker and more solid internal and external shells. The piles and shells are generally shaped to follow the contour of the reactor and connected piping. It is therefore necessary to have available a study bracing system to keep the pile intact during the various handling and assembly operations. The fastening system must also exert an effect on the edge of the pile to prevent the sheets making it up from shifting in relation to each other. The description is given of a fastening system that includes an oblong section to be fitted along the edges of the piles up sheets; bracing substantially perpendicular to the oblong section, to space the sheets of the stack in pairs; and a maintaining system, normally perpendicular to the oblong section, to enable the fastener to be clipped to the edge of the sheets by bending it around the edge of each sheet of the pile [fr

Modelling of the local chemistry in stagnant areas in the PWR primary circuit

International Nuclear Information System (INIS)

Reid, Rick; Fruzzetti, Keith; Ahluwalia, Al; Summe, Alex; Dame, Cecile; Schmitt, Kyle

2014-01-01

MRP-236 demonstrated a correlation between stagnant or low flow conditions and stress corrosion cracking (SCC) of stainless steel components in the PWR primary system. Of the approximately 140 SCC events documented (affecting 15 different components), 83% involved stagnant or low flow conditions that were likely to be associated with chemical environments different from the well mixed bulk coolant. The chemistry in such locations is typically not monitored, and sampling is difficult or impossible. Actions to improve chemistry in regions of low or no coolant flow, such as flushing, cycling of components and imposition of more stringent make up water chemistry controls affect both operational costs and outage schedules. Similarly, design changes to improve flow in affected areas are costly or impracticable. Improving the understanding of the factors controlling chemistry in such areas and development of the capability to predict typical and worst case conditions will allow an informed assessment of procedural actions and/or design changes to improve local chemistry and thereby reduce SCC susceptibility. A project was undertaken to develop a model to predict local chemistry conditions in stagnant locations. The model comprises the iterative application of the EPRI MULTEQ solution chemistry equilibrium code and standard thermodynamic relationships to predict local chemistry conditions considered likely to have been present at the surfaces of components when SCC was initiated. The starting chemistry conditions are based on PWR primary system chemistry from different plant maneuvers (e.g., startup and shutdown conditions). The model was applied to three example components where SCC has occurred in the field. The selected components were: control rod drive mechanism canopy seals; valve drain lines; and reactor vessel o-ring leak-off lines. This paper provides a summary of the model and predicted local chemistry conditions that develop for the three example component as a

The New Zealand Food Composition Database: A useful tool for assessing New Zealanders' nutrient intake.

Science.gov (United States)

Sivakumaran, Subathira; Huffman, Lee; Sivakumaran, Sivalingam

2018-01-01

A country-specific food composition databases is useful for assessing nutrient intake reliably in national nutrition surveys, research studies and clinical practice. The New Zealand Food Composition Database (NZFCDB) programme seeks to maintain relevant and up-to-date food records that reflect the composition of foods commonly consumed in New Zealand following Food Agricultural Organisation of the United Nations/International Network of Food Data Systems (FAO/INFOODS) guidelines. Food composition data (FCD) of up to 87 core components for approximately 600 foods have been added to NZFCDB since 2010. These foods include those identified as providing key nutrients in a 2008/09 New Zealand Adult Nutrition Survey. Nutrient data obtained by analysis of composite samples or are calculated from analytical data. Currently >2500 foods in 22 food groups are freely available in various NZFCDB output products on the website: www.foodcomposition.co.nz. NZFCDB is the main source of FCD for estimating nutrient intake in New Zealand nutrition surveys. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adult Nutrient Intakes from Current National Dietary Surveys of European Populations

Directory of Open Access Journals (Sweden)

Holly L. Rippin

2017-11-01

Full Text Available The World Health Organization (WHO encourages countries to undertake national dietary survey (NDS but implementation and reporting is inconsistent. This paper provides an up-to-date review of adult macro and micronutrient intakes in European populations as reported by NDS. It uses WHO Recommended Nutrient Intakes (RNIs to assess intake adequacy and highlight areas of concern. NDS information was gathered primarily by internet searches and contacting survey authors and nutrition experts. Survey characteristics and adult intakes by gender/age group were extracted for selected nutrients and weighted means calculated by region. Of the 53 WHO Europe countries, over a third (n = 19, mainly Central & Eastern European countries (CEEC, had no identifiable NDS. Energy and nutrient intakes were extracted for 21 (40% countries but differences in age group, methodology, under-reporting and nutrient composition databases hindered inter-country comparisons. No country met more than 39% WHO RNIs in all age/gender groups; macronutrient RNI achievement was poorer than micronutrient. Overall RNI attainment was slightly worse in CEEC and lower in women and female elderly. Only 40% countries provided adult energy and nutrient intakes. The main gaps lie in CEEC, where unknown nutrient deficiencies may occur. WHO RNI attainment was universally poor for macronutrients, especially for women, the female elderly and CEEC. All countries could be encouraged to report a uniform nutrient set and sub-analyses of nationally representative nutrient intakes.

Presidential Green Chemistry Challenge: 2016 Small Business Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2016 award winner, Verdezyne, developed a yeast to produce USDA Certified Biobased dodecanedioic acid (DDDA) used to make high performance nylon 6,12. Lower greenhouse gas emissions, no high temperature or nitric acid

Predicting steam generator crevice chemistry

International Nuclear Information System (INIS)

Burton, G.; Strati, G.

2006-01-01

'Full text:' Corrosion of steam cycle components produces insoluble material, mostly iron oxides, that are transported to the steam generator (SG) via the feedwater and deposited on internal surfaces such as the tubes, tube support plates and the tubesheet. The build up of these corrosion products over time can lead to regions of restricted flow with water chemistry that may be significantly different, and potentially more corrosive to SG tube material, than the bulk steam generator water chemistry. The aim of the present work is to predict SG crevice chemistry using experimentation and modelling as part of AECL's overall strategy for steam generator life management. Hideout-return experiments are performed under CANDU steam generator conditions to assess the accumulation of impurities in hideout, and return from, model crevices. The results are used to validate the ChemSolv model that predicts steam generator crevice impurity concentrations, and high temperature pH, based on process parameters (e.g., heat flux, primary side temperature) and blowdown water chemistry. The model has been incorporated into ChemAND, AECL's system health monitoring software for chemistry monitoring, analysis and diagnostics that has been installed at two domestic and one international CANDU station. ChemAND provides the station chemists with the only method to predict SG crevice chemistry. In one recent application, the software has been used to evaluate the crevice chemistry based on the elevated, but balanced, SG bulk water impurity concentrations present during reactor startup, in order to reduce hold times. The present paper will describe recent hideout-return experiments that are used for the validation of the ChemSolv model, station experience using the software, and improvements to predict the crevice electrochemical potential that will permit station staff to ensure that the SG tubes are in the 'safe operating zone' predicted by Lu (AECL). (author)

Chemistry and radiochemistry strategies supported by FA3-EPRTM and UK-EPRTM auxiliary systems: performances and control

International Nuclear Information System (INIS)

Tigeras, Arancha; Fourment, Pierre; Elgallaf; Anas; Chupin, Antoine; Fauvel, Nicola

2012-09-01

The design and the operation of auxiliary systems play an essential role in: - the preservation of the primary circuit integrity, - the prevention of hydrogen risk, - the control of the boron concentration and radioactivity, - the application of pH and zinc programmes. While the source term generation mainly depends on the primary circuit material and primary coolant chemistry conditioning, the source term spreading is directly linked to the auxiliary systems treatment and performances. Indeed, the auxiliary systems regulate the boron, hydrogen, lithium and zinc injection as well as the countermeasures to ensure the reactivity control and the hazardous H 2 /O 2 mixture prevention. The main principles governing the chemistry and radiochemistry in the auxiliary systems are based on the application of: - Design features for hydrogen and boron management. - Criteria for selecting the appropriate material of each system considering the functional requirements and the source term build up reduction. - Measures for minimizing the activity deposition on the surfaces of components and pipings. - Adequate and reliable systems of purification for reducing the accumulation of liquid/gas radioactivity and impurities in the circuits and for optimizing the waste production. - Chemistry program for limiting the material corrosion of auxiliary systems and preventing the source term transfer to the core. - Appropriate sampling locations and equipment to monitor the chemistry and radiochemistry parameters. This paper describes the operation of the main auxiliary systems of FLAMANVILLE3-EPR TM and UK-EPR- TM participating in the chemistry/radiochemistry management such as Chemical and Volume Control System (CVCS), Reactor Borated Water Make-up System (RBWMS), Coolant Treatment System (CTS), Gaseous Waste Processing System (GWPS), Fuel Pool Purification System (PTR [FPPS/FPCS]) also. The performances requested to these systems and the chemistry programs applied to them are discussed

Nutrient and dissolved organic carbon removal from water using mining and metallurgical by-products.

Science.gov (United States)

Wendling, Laura A; Douglas, Grant B; Coleman, Shandel; Yuan, Zheng

2012-05-15

Excess nutrient input to water bodies frequently results in algal blooms and development of oxygen deficient conditions. Mining or metallurgical by-products can potentially be utilised as filtration media within water treatment systems such as constructed wetlands, permeable reactive barriers, or drain liners. These materials may offer a cost-effective solution for the removal of nutrients and dissolved organic carbon (DOC) from natural waters. This study investigated steel-making, alumina refining (red mud and red sand) and heavy mineral processing by-products, as well as the low-cost mineral-based material calcined magnesia, in laboratory column trials. Influent water and column effluents were analysed for pH and flow rate, alkalinity, nutrient species and DOC, and a range of major cations and anions. In general, by-products with high Ca or Mg, and to a lesser extent those with high Fe content, were well-suited to nutrient and DOC removal from water. Of the individual materials examined, the heavy mineral processing residue neutralised used acid (NUA) exhibited the highest sorption capacity for P, and removed the greatest proportions of all N species and DOC from influent water. In general, NUA and mixtures containing NUA, particularly those with calcined magnesia or red mud/red sand were the most effective in removing nutrients and DOC from influent water. Post-treatment effluents from columns containing NUA and NUA/steel-making by-product, NUA/red sand and NUA/calcined magnesia mixtures exhibited large reductions in DOC, P and N concentrations and exhibited a shift in nutrient ratios away from potential N- and Si-limitation and towards potential P-limitation. If employed as part of a large-scale water treatment scheme, use of these mining and metallurgical by-products for nutrient removal could result in reduced algal biomass and improved water quality. Identification and effective implementation of mining by-products or blends thereof in constructed wetlands

Research in nuclear chemistry: current status and future perspectives

International Nuclear Information System (INIS)

Reddy, A.V.R.

2007-01-01

Research in nuclear chemistry has seen a huge growth over the last few decades. The large umbrella of nuclear chemistry includes several research areas such as nuclear fission, reactions, spectroscopy, nuclear probes and nuclear analytical techniques. Currently, nuclear chemistry research has extended its horizon into various applications like nuclear medicine, isotopes for understanding physico chemical processes, and addressing environmental and biomedical problems. Tremendous efforts are going on for synthesizing new elements (isotopes), isolating physically or chemically wherever possible and investigating their properties. Theses studies are useful to understand nuclear and chemical properties at extreme ends of instability. In addition, nuclear chemists are making substantial contribution to astrophysics and other related areas. During this talk, a few of the contributions made by nuclear chemistry group of BARC will be discussed and possible future areas of research will be enumerated. (author)

Teaching Triple Science: GCSE Chemistry

Science.gov (United States)

Learning and Skills Network (NJ3), 2007

2007-01-01

The Department for Children, Schools and Families (DCSF) has contracted with the Learning and Skills Network to support awareness and take-up of Triple Science GCSEs through the Triple Science Support Programme. This publication provides an introduction to teaching and learning approaches for the extension topics within GCSE Chemistry. It…

Health improvement of domestic hot tap water supply Gusev, Kaliningrad Region, Russia. Make-up water tank project. Final report

Energy Technology Data Exchange (ETDEWEB)

Aagaard, Joergen

1998-07-01

This report describes the project `Health Improvement of Domestic Hot Tap Water Supply, Gusev, Kaliningrad, Russia`, which was carried out in the autumn of 1996 and financed by the Danish Environmental Protection Agency, the Danish Energy Agency and Gusev Municipality. The project proposal and application outlined the following objectives: Erection of system so that hot tap water, which is tapped directly from the district heating system, obtains an acceptable quality in health terms; Complete training and education, so that the plant can be operated and maintained by the power station`s staff and rehabilitation projects within supply of domestic water and district heating can be promoted to the greatest possible extent; Systems for heat treatment of make-up water were implemented in less than three months; The project was carried out in close Danish-Russian co-operation from the beginning of engineering to the commissioning and resulted in transfer and demonstration of know-how and technology; Information was recorded on the existing domestic water and heat supply systems as well as on the treatment of sewage, and recommendations for rehabilitation projects were made. Previously, when the temperature in the district heating system was relatively high, a heat treatment apparently took place in the district heating system. However, due to the current poor economic situation there are no means with which to buy the fuel quantities necessary to maintain the previously normal district heating temperature. In the new concept the cold make-up water is heated to >80 deg. C as required by the health authorities before it is led to the district heating return system and subsequently heated to the actual supply temperature of 50-60 deg. C. The energy consumption in the two concepts is approximately the same. A 1,000 m{sup 3} tank with heating coils was erected between the make-up water system and the district heating system. The tank should equalise the daily capacity

Modeling Nutrient Release in the Tai Lake Basin of China: Source Identification and Policy Implications

Science.gov (United States)

Liu, Beibei; Liu, Heng; Zhang, Bing; Bi, Jun

2013-03-01

Because nutrient enrichment has become increasingly severe in the Tai Lake Basin of China, identifying sources and loads is crucial for watershed nutrient management. This paper develops an empirical framework to estimate nutrient release from five major sectors, which requires fewer input parameters and produces acceptable accuracy. Sectors included are industrial manufacturing, livestock breeding (industrial and family scale), crop agriculture, household consumption (urban and rural), and atmospheric deposition. Results show that in the basin (only the five sectors above), total nutrient loads of nitrogen (N) and phosphorus (P) into aquatic systems in 2008 were 33043.2 tons N a-1 and 5254.4 tons P a-1, and annual area-specific nutrient loads were 1.94 tons N km-2 and 0.31 tons P km-2. Household consumption was the major sector having the greatest impact (46 % in N load, 47 % in P load), whereas atmospheric deposition (18 %) and crop agriculture (15 %) sectors represented other significant proportions of N load. The load estimates also indicate that 32 % of total P came from the livestock breeding sector, making it the second largest phosphorus contributor. According to the nutrient pollution sectors, six best management practices are selected for cost-effectiveness analysis, and feasible options are recommended. Overall, biogas digester construction on industrial-scale farms is proven the most cost-effective, whereas the building of rural decentralized facilities is the best alternative under extreme financial constraint. However, the reduction potential, average monetary cost, and other factors such as risk tolerance of policy makers should all be considered in the actual decision-making process.

Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia.

Science.gov (United States)

van der Wulp, Simon A; Damar, Ario; Ladwig, Norbert; Hesse, Karl-J

2016-09-30

The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377m(3)s(-1) entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174tons and 14 to 60tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Variability of nutrients intake, lipid profile and cardiovascular mortality among geographical areas in Spain: The DRECE study.

Science.gov (United States)

Gómez de la Cámara, Agustín; De Andrés Esteban, Eva; Urrútia Cuchí, Gerard; Calderón Sandubete, Enrique; Rubio Herrera, Miguel Ángel; Menéndez Orenga, Miguel; Lora Pablos, David

2017-11-07

It has often been suggested that cardiovascular mortality and their geographical heterogeneity are associated with nutrients intake patterns and also lipid profile. The large Spanish study Dieta y Riesgo de Enfermedades Cardiovasculares en España (DRECE) investigated this theory from 1991 to 2010. Out of the 4,783 Spanish individuals making up the DRECE cohort, 220 subjects (148 men and 72 women) died (4.62%) during the course of the study. The mean age of patients who died from cardiovascular causes (32 in all) was 61.08 years 95% CI (57.47-64.69) and 70.91% of them were males. The consumption of nutrients and the lipid profile by geographical area, studied by geospatial models, showed that the east and southern area of the country had the highest fat intake coupled to a high rate of unhealthy lipid profile. It was concluded that the spatial geographical analysis showed a relationship between high fat intake, unhealthy lipid profile and cardiovascular mortality in the different geographical areas, with a high variability within the country.

Programming chemistry in DNA-addressable bioreactors

DEFF Research Database (Denmark)

Fellermann, H.; Cardelli, L.

2014-01-01

. These markers serve as compartment addresses and allow for their targeted transport and fusion, thereby enabling reactions of previously separated chemicals. The overall system organization allows for the set-up of programmable chemistry in microfluidic or other automated environments. We introduce a simple...

Including spatial data in nutrient balance modelling on dairy farms

Science.gov (United States)

van Leeuwen, Maricke; van Middelaar, Corina; Stoof, Cathelijne; Oenema, Jouke; Stoorvogel, Jetse; de Boer, Imke

2017-04-01

at Dutch dairy farms. We selected two dairy farms located on cover sands in the Netherlands. One farm was located on relatively homogeneous soil type, and one on many different soil types within the sandy soils. A full year of data of N and P inputs and outputs on farm and field level were provided by the farmers, including field level yields, yield composition, manure composition, degree of grazing and degree of mowing. Soil heterogeneity was defined as the number of soil units within the farm corrected for surface area, and quantified from the Dutch 1:50.000 soil map. N and P balances at farm and field level were determined, as well as differences in nutrient use efficiency, leaching, and N emission. We will present the effect of the spatial scale on nutrient balance analysis and discuss to which degree any differences are caused by within-farm land management and soil variation. This study highlights to which extent within-farm land management and soil variation should be taken into account when modelling nutrient flows and nutrient use efficiencies at farm level, to contribute to field-based decision making for improved land management.

Seawater Carbonate Chemistry of Deep-sea Coral Beds off the Northwestern Hawaiian Islands

Science.gov (United States)

Brooks, J.; Shamberger, K.; Roark, E. B.; Miller, K.; Baco-Taylor, A.

2016-02-01

Many species of deep-sea octocorals produce calcium carbonate (CaCO3) skeletons and form coral beds that support diverse ecosystems crucial to fisheries. The geochemistry of deep-sea coral skeletons can provide valuable paleoceanographic information on ocean circulation and nutrient cycling. Deep-sea corals in the older bottom waters of the Pacific are naturally exposed to higher carbon dioxide (CO2) concentrations and lower pH than in the Atlantic where much of the previous deep-sea coral work has occurred. Therefore, some Pacific deep-sea corals may live and calcify in waters that are corrosive to their skeletons, but there have been few current seawater carbonate chemistry measurements of the waters surrounding deep-sea coral beds to assess this. The input of anthropogenic atmospheric CO2 known as ocean acidification (OA) lowers ocean pH and causes an expansion of these corrosive waters. Seawater carbonate chemistry must be characterized before accurate predictions can be made for the effects of OA on these important ecosystems. Total Alkalinity (TA) and Dissolved Inorganic Carbon (DIC) samples were collected in the fall of 2014 and 2015 from the surface to 1450 m depth off the Northwestern Hawaiian Island chain where deep-sea octocorals are found. The partial pressure of CO2 increased and pH, calcite saturation state (Ωca) and aragonite saturation state (Ωar) decreased with increasing latitude and depth. Notably, waters were undersaturated with respect to calcite and aragonite (Ωca and Ωar less than 1) below 800 m and 500 m, respectively. Therefore, deep-sea corals below these depths must calcify in waters that are thermodynamically favorable for CaCO3 dissolution. How deep-sea octocorals cope with such adverse seawater chemistry is critical to understanding future effects of OA. It is not known whether OA is currently negatively impacting deep-sea octocorals, but their naturally acidified environments could make them particularly susceptible to OA.

Nutrient balances in the forest energy cycle

International Nuclear Information System (INIS)

Olsson, Bengt

2006-02-01

. An improved national statistics is needed, including the extent of slash harvesting and the amounts of ashes produced from forest biomass, to keep up running estimates of nutrient fluxes through the forest energy cycle

Uranium chemistry: significant advances

International Nuclear Information System (INIS)

Mazzanti, M.

2011-01-01

The author reviews recent progress in uranium chemistry achieved in CEA laboratories. Like its neighbors in the Mendeleev chart uranium undergoes hydrolysis, oxidation and disproportionation reactions which make the chemistry of these species in water highly complex. The study of the chemistry of uranium in an anhydrous medium has led to correlate the structural and electronic differences observed in the interaction of uranium(III) and the lanthanides(III) with nitrogen or sulfur molecules and the effectiveness of these molecules in An(III)/Ln(III) separation via liquid-liquid extraction. Recent work on the redox reactivity of trivalent uranium U(III) in an organic medium with molecules such as water or an azide ion (N 3 - ) in stoichiometric quantities, led to extremely interesting uranium aggregates particular those involved in actinide migration in the environment or in aggregation problems in the fuel processing cycle. Another significant advance was the discovery of a compound containing the uranyl ion with a degree of oxidation (V) UO 2 + , obtained by oxidation of uranium(III). Recently chemists have succeeded in blocking the disproportionation reaction of uranyl(V) and in stabilizing polymetallic complexes of uranyl(V), opening the way to to a systematic study of the reactivity and the electronic and magnetic properties of uranyl(V) compounds. (A.C.)

Assessing Student Knowledge of Chemistry and Climate Science Concepts Associated with Climate Change: Resources to Inform Teaching and Learning

Science.gov (United States)

Versprille, Ashley; Zabih, Adam; Holme, Thomas A.; McKenzie, Lallie; Mahaffy, Peter; Martin, Brian; Towns, Marcy

2017-01-01

Climate change is one of the most critical problems facing citizens today. Chemistry faculty are presented with the problem of making general chemistry content simultaneously relevant and interesting. Using climate science to teach chemistry allows faculty to help students learn chemistry content in a rich context. Concepts related to…

Presidential Green Chemistry Challenge: 2010 Greener Synthetic Pathways Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2010 award winners, Dow and BASF, jointly developed a route to make propylene oxide from hydrogen peroxide that eliminates almost all waste and greatly reduces water and energy use.

Emphasizing the process of science using demonstrations in conceptual chemistry

Science.gov (United States)

Lutz, Courtney A.

The purpose of this project was to teach students a method for employing the process of science in a conceptual chemistry classroom when observing a demonstration of a discrepant event. Students observed six demonstrations throughout a trimester study of chemistry and responded to each demonstration by asking as many questions as they could think of, choosing one testable question to answer by making as many hypotheses as possible, and choosing one hypothesis to make predictions about observed results of this hypothesis when tested. Students were evaluated on their curiosity, confidence, knowledge of the process of science, and knowledge of the nature of science before and after the six demonstrations. Many students showed improvement in using or mastery of the process of science within the context of conceptual chemistry after six intensive experiences with it. Results of the study also showed students gained confidence in their scientific abilities after completing one trimester of conceptual chemistry. Curiosity and knowledge of the nature of science did not show statistically significant improvement according to the assessment tool. This may have been due to the scope of the demonstration and response activities, which focused on the process of science methodology instead of knowledge of the nature of science or the constraints of the assessment tool.

Algae potential resource assessment for the energy and chemistry sectors in France by 2030

International Nuclear Information System (INIS)

Kerlero De Rosbo, Guillaume; Payen, Luc; Bernard, Olivier; Mairet, Francis; Grimaud, Ghjuvan; Delclaux, Etienne; Rey, David; Ras De Moncuit, Monique; Houdon, Aude-Claire; Gagnepain, Bruno; Gueudet, Alice; El Khamlichi, Aicha; Delalande, Claire; Eglin, Thomas; Pouet, Jean-Christophe; Allouche, Yohan; Lombard, Christophe; Mhiri, Tarek; Mazzenga, Anthony; Lasserre, Thomas; Potin, Philippe; Kaas, Raymond; Lecurieux-Belfond, Laura

2014-07-01

To address environmental and climate issues, alternative technologies to fossil resources are sought after, both for the production of fuels and of chemicals. Algae appear as an attractive solution and have applications in the food, feed, energy or chemistry at large. A study funded by ADEME and conducted by ENEA, a consulting firm for energy and sustainable development for the industrial sector, in partnership with INRIA assessed the potential of algal French resources (micro- and macro-algae) for the production of advanced bio-fuels and molecules of interest (bio-plastic, nutrients etc.) in 2030. This assessment is based both on a model of the French national resources (physical production potential without the use of agricultural land) and what the we now know of the markets concerned and their projection 2030. The analysis shows a physical potential output of up to 9% of the French bio-diesel consumption in 2030 and enough to supply many European markets in algal bio-products. R and d efforts are however required to achieve sufficient technical and economic performance to fully exploit this potential

Primary Water Chemistry Control during a Planned Outage at Bruce Power

International Nuclear Information System (INIS)

Ma, Guoping; Nashiem, Rod; Matheson, Shane; Yabar, Berman; Harper, Bill; Roberts, John G.

2012-09-01

Bruce Power has developed a comprehensive outage water chemistry program, which includes both primary and secondary chemistry requirements during planned outages. The purpose of the program is to emphasize the chemistry requirements during outages and subsequent start-ups in order to maintain the integrity of the systems, minimise activity transport and radiation fields, reduce the Carbon-14 release, and to ensure that the requirements are integrated with the outage management program. Prior to a planned outage, Station Chemical Technical Sections identify outage chemistry requirements to Operations and Outage Planning and ensure that work necessary to correct system chemistry issues is within outage work scope. The outage water chemistry program provides direction for establishing alternative sampling locations as demanded by the system configuration during the outage and identifies outage prerequisites for nuclear system purification capabilities. These requirements are contained in an outage checklist. The paper mainly highlights the primary water chemistry issues and chemistry control strategies during planned outages and discusses challenges and successes. (authors)

Carbon and nutrient use efficiencies optimally balance stoichiometric imbalances

Science.gov (United States)

Manzoni, Stefano; Čapek, Petr; Lindahl, Björn; Mooshammer, Maria; Richter, Andreas; Šantrůčková, Hana

2016-04-01

Decomposer organisms face large stoichiometric imbalances because their food is generally poor in nutrients compared to the decomposer cellular composition. The presence of excess carbon (C) requires adaptations to utilize nutrients effectively while disposing of or investing excess C. As food composition changes, these adaptations lead to variable C- and nutrient-use efficiencies (defined as the ratios of C and nutrients used for growth over the amounts consumed). For organisms to be ecologically competitive, these changes in efficiencies with resource stoichiometry have to balance advantages and disadvantages in an optimal way. We hypothesize that efficiencies are varied so that community growth rate is optimized along stoichiometric gradients of their resources. Building from previous theories, we predict that maximum growth is achieved when C and nutrients are co-limiting, so that the maximum C-use efficiency is reached, and nutrient release is minimized. This optimality principle is expected to be applicable across terrestrial-aquatic borders, to various elements, and at different trophic levels. While the growth rate maximization hypothesis has been evaluated for consumers and predators, in this contribution we test it for terrestrial and aquatic decomposers degrading resources across wide stoichiometry gradients. The optimality hypothesis predicts constant efficiencies at low substrate C:N and C:P, whereas above a stoichiometric threshold, C-use efficiency declines and nitrogen- and phosphorus-use efficiencies increase up to one. Thus, high resource C:N and C:P lead to low C-use efficiency, but effective retention of nitrogen and phosphorus. Predictions are broadly consistent with efficiency trends in decomposer communities across terrestrial and aquatic ecosystems.

Institute of Bioinorganic and Radiopharmaceutical Chemistry. Annual report 2001

International Nuclear Information System (INIS)

Johannsen, B.; Seifert, S.

2002-01-01

In 2001 the Forschungszentrum Rossendorf e.V. continued and further developed its basic and application-oriented research. Research at the Institute of Bioinorganic and Radiopharmaceutical Chemistry, one of five institutes in the Research Centre, was focused on radiotracers as molecular probes to make the human body biochemically transparent with regard to individual molecular reactions. As illustrated by the large number of contributions in this report, the Institute is predominantly engaged in the coordination chemistry and radiopharmacology of technetium and rhenium. (orig.)

Qualifying works of the Department of nuclear chemistry (1963 - 2006)

International Nuclear Information System (INIS)

Kuruc, J.

2007-01-01

In this review qualifying works (theses - bachelor, master, PhD., DrSc., habilitation and inauguration theses) elaborated at the Department of nuclear chemistry, Faculty of Natural Chemistry, Comenius University in Bratislava during forty years (from origin of the Section of Nuclear chemistry in 1963 up to 2006 are presented. During this time, in totally, 3 bachelor theses, 265 master theses, 24 PhD. (CSc.) and 10 PhD. dissertanions, 2 DrSc. dissertanions as well as 8 habilitation and one inauguration these were defended (author)

Salmon-mediated nutrient flux in selected streams of the Columbia River basin, USA

Science.gov (United States)

Kohler, Andre E.; Kusnierz, Paul C.; Copeland, Timothy; Venditti, David A.; Denny, Lytle; Gable, Josh; Lewis, Bert; Kinzer, Ryan; Barnett, Bruce; Wipfli, Mark S.

2013-01-01

Salmon provide an important resource subsidy and linkage between marine and land-based ecosystems. This flow of energy and nutrients is not uni-directional (i.e., upstream only); in addition to passive nutrient export via stream flow, juvenile emigrants actively export nutrients from freshwater environments. In some cases, nutrient export can exceed import. We evaluated nutrient fluxes in streams across central Idaho, USA using Chinook salmon (Oncorhynchus tshawytscha) adult escapement and juvenile production data from 1998 to 2008. We found in the majority of stream-years evaluated, adults imported more nutrients than progeny exported; however, in 3% of the years, juveniles exported more nutrients than their parents imported. On average, juvenile emigrants exported 22 ± 3% of the nitrogen and 30 ± 4% of the phosphorus their parents imported. This relationship was density dependent and nonlinear; during periods of low adult abundance juveniles were larger and exported up to 194% and 268% of parental nitrogen and phosphorus inputs, respectively. We highlight minimum escapement thresholds that appear to 1) maintain consistently positive net nutrient flux and 2) reduce the average proportional rate of export across study streams. Our results suggest a state-shift occurs when adult spawner abundance falls below a threshold to a point where the probability of juvenile nutrient exports exceeding adult imports becomes increasingly likely.

Safety of tattoos and permanent make-up. Adverse health effects and experience with the Council of Europe Resolution (2008)1.

OpenAIRE

PICCININI Paola; PAKALIN Sazan; CONTOR LAURA; BIANCHI IVANA

2015-01-01

In the last decades, the proportion of the tattooed population has been increasing all over the world, particularly in the young generations. Concerns about the possible health problems associated to tattoos and permanent make up (PMU) have also grown together with the number of tattoo/PMU applications and removals. The Council of Europe Resolution (CoE ResAP)(2008)1 [1], on requirements and criteria for the safety of tattoos and permanent make-up, is a non-binding internationally recog...

Presidential Green Chemistry Challenge: 2003 Greener Synthetic Pathways Award

Science.gov (United States)

Presidential Green Chemistry Challenge 2003 winner, Sud-Chemie, developed a synthesis for solid oxide catalysts used to make hydrogen and clean fuels. The process creates little wastewater, no nitrates, and no or little NOx.

Nutrient Removal Efficiency of Rhizophora mangle (L. Seedlings Exposed to Experimental Dumping of Municipal Waters

Directory of Open Access Journals (Sweden)

Claudia Maricusa Agraz-Hernández

2018-03-01

Full Text Available Mangrove forests are conspicuous components of tropical wetlands that sustain continuous exposure to wastewater discharges commonly of municipal origins. Mangroves can remove nutrients from these waters to fulfill their nutrients demand, although the effects of continuous exposure are unknown. An experimental greenhouse imitating tidal regimes was built to measure the efficiency of mangrove seedlings to incorporate nutrients, growth and above biomass production when exposed to three periodic wastewater discharges. The experiment totaled 112 d. Nutrient removal by the exposed group, such as phosphates, ammonia, nitrites, nitrates and dissolved inorganic nitrogen (97%, 98.35%, 71.05%, 56.57% and 64.36%, respectively was evident up to the second dumping. By the third dumping, all nutrient concentrations increased in the interstitial water, although significant evidence of removal by the plants was not obtained (p > 0.05. Nutrient concentrations in the control group did not change significantly throughout the experiment (p > 0.05. Treated plants increased two-fold in stem girth when compared to the control (p < 0.05, although control plants averaged higher heights (p < 0.05. Biomass of treated group increased up to 45% against 37% of the control during the duration of the experiment (p < 0.05. We suggest that nutrient removal efficiency of mangroves is linked to the maintenance of oxic conditions in the pore-water because of oxygen transference from their aerial to their subterranean radicular system that facilitates the oxidation of reduced nitrogen compounds and plants uptake. Nevertheless, continuous inflows of wastewater would lead to eutrophication, establishment of anoxic conditions in water and soil, and lessening of nutrient absorption of mangroves.

Urban trees reduce nutrient leaching to groundwater.

Science.gov (United States)

Nidzgorski, Daniel A; Hobbie, Sarah E

2016-07-01

Many urban waterways suffer from excess nitrogen (N) and phosphorus (P), feeding algal blooms, which cause lower water clarity and oxygen levels, bad odor and taste, and the loss of desirable species. Nutrient movement from land to water is likely to be influenced by urban vegetation, but there are few empirical studies addressing this. In this study, we examined whether or not urban trees can reduce nutrient leaching to groundwater, an important nutrient export pathway that has received less attention than stormwater. We characterized leaching beneath 33 trees of 14 species, and seven open turfgrass areas, across three city parks in Saint Paul, Minnesota, USA. We installed lysimeters at 60 cm depth to collect soil water approximately biweekly from July 2011 through October 2013, except during winter and drought periods, measured dissolved organic carbon (C), N, and P in soil water, and modeled water fluxes using the BROOK90 hydrologic model. We also measured soil nutrient pools (bulk C and N, KCl-extractable inorganic N, Brays-P), tree tissue nutrient concentrations (C, N, and P of green leaves, leaf litter, and roots), and canopy size parameters (leaf biomass, leaf area index) to explore correlations with nutrient leaching. Trees had similar or lower N leaching than turfgrass in 2012 but higher N leaching in 2013; trees reduced P leaching compared with turfgrass in both 2012 and 2013, with lower leaching under deciduous than evergreen trees. Scaling up our measurements to an urban subwatershed of the Mississippi River (~17 400 ha, containing ~1.5 million trees), we estimated that trees reduced P leaching to groundwater by 533 kg in 2012 (0.031 kg/ha or 3.1 kg/km 2 ) and 1201 kg in 2013 (0.069 kg/ha or 6.9 kg/km 2 ). Removing these same amounts of P using stormwater infrastructure would cost $2.2 million and $5.0 million per year (2012 and 2013 removal amounts, respectively). © 2016 by the Ecological Society of America.

Design of the Demineralized Water Make-up Line to Maintain the Normal Pool Water Level of the Reactor Pool in the Research Reactor

International Nuclear Information System (INIS)

Yoon, Hyun Gi; Choi, Jung Woon; Yoon, Ju Hyeon; Chi, Dae Young

2012-01-01

In many research reactors, hot water layer system (HWLS) is used to minimize the pool top radiation level. Reactor pool divided into the hot water layer at the upper part of pool and the cold part below the hot water layer with lower temperature during normal operation. Water mixing between these layers is minimized because the hot water layer is formed above cold water. Therefore the hot water layer suppresses floatation of cold water and reduces the pool top radiation level. Pool water is evaporated form the surface to the building hall because of high temperature of the hot water layer; consequently the pool level is continuously fallen. Therefore, make-up water is necessary to maintain the normal pool level. There are two way to supply demineralized water to the pool, continuous and intermittent methods. In this system design, the continuous water make-up method is adopted to minimize the disturbance of the reactor pool flow. Also, demineralized water make-up is connected to the suction line of the hot water layer system to raise the temperature of make-up water. In conclusion, make-up demineralized water with high temperature is continuously supplied to the hot water layer in the pool

2016 Nobel Prize in Chemistry1

Indian Academy of Sciences (India)

open-up a new area of chemistry in a paradigm shifting man- ner. .... tives that undergo facile reactions, in the presence of metal-ion chelation with ... shuttle moves from one station to .... ATP hydrolysis and the rotor action of the enzyme. In the ...

Solar process heat for industry, seawater desalination and solar chemistry; Solare Prozesswaerme fuer Industrie, Meerwasserentsalzung und Solarchemie

Energy Technology Data Exchange (ETDEWEB)

Hennecke, K. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Berlin (Germany); Lokurlu, A. [Solitem GmbH, Aachen (Germany); Rommel, M. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany); Spaete, F. [Fachhochschule Aachen, Juelich (Germany). Solar-Institut Juelich

2006-02-15

The examples discussed in this paper show that solar process heat can make an important contribution to climate protection and resource conservation. Marketable technologies providing temperatures up to approx. 200 C will be available in the short to medium term future. Continue low prices for fossil fuels and high consulting and planning costs impede the further spread of these technologies. Politicians must be called upon to facilitate the development of the market through suitable promotion programmes. There is still a long-term requirement for research, especially regarding high-temperature applications and solar chemistry.

Chemistry and physics

International Nuclear Information System (INIS)

Broerse, J.J.; Barendsen, G.W.; Kal, H.B.; Kogel, A.J. van der

1983-01-01

This book contains the extended abstracts of the contributions of the poster workshop sessions on chemistry and physics of the 7th international congress of radiation research. They cover the following main topics: primary processes in radiation physics and chemistry, general chemistry in radiation chemistry, DNA and model systems in radiation chemistry, molecules of biological interest in radiation chemistry, techniques in radiation chemistry, hot atom chemistry. refs.; figs.; tabs

Nutrient dynamics and primary production in a pristine coastal mangrove ecosystem: Andaman Islands, India

Science.gov (United States)

Jenkins, E. N.; Nickodem, K.; Siemann, A. L.; Hoeher, A.; Sundareshwar, P. V.; Ramesh, R.; Purvaja, R.; Banerjee, K.; Manickam, S.; Haran, H.

2012-12-01

Mangrove ecosystems play a key role in supporting coastal food webs and nutrient cycles in the coastal zone. Their strategic position between the land and the sea make them important sites for land-ocean interaction. As part of an Indo-US summer field course we investigated changes in the water chemistry in a pristine mangrove creek located at Wright Myo in the Andaman Islands, India. This study was conducted during the wet season (June 2012) to evaluate the influence of the coastal mangrove wetlands on the water quality and productivity in adjoining pelagic waters. Over a full tidal cycle spanning approximately 24 hrs, we measured nutrient concentrations and other ancillary parameters (e.g. dissolved oxygen, turbidity, salinity, etc.) hourly to evaluate water quality changes in incoming and ebbing tides. Nutrient analyses had the following concentration ranges (μM): nitrite 0.2-0.9, nitrate 2.0-11.5, ammonium 1.3-7.5, dissolved inorganic phosphate 0.7-2.8. The dissolved inorganic nitrogen to dissolved inorganic phosphate (DIN/DIP) ratio was very low relative to an optimal ratio, suggesting growth is nitrogen limited. In addition, we conducted primary production assays to investigate the factors that controlled primary production in this pristine creek. The experiment was carried out in situ using the Winkler method at low and high tide. Four-hour incubation of light and dark bottles representing a fixed control, non-fertilized, fertilized with nitrate, and fertilized with phosphate enabled the measurement of both net oxygen production and dark respiration. The low tide experiment suggests the ecosystem is heterotrophic because the oxygen measured in the light bottles was consistently less than that of the dark bottles. This result may be an experimental artifact of placing the glass bottles in the sun for too long prior to incubation, potentially leading to photolysis of large organic molecules in the light bottles. The high tide experiment also displayed

Nitrogen limitation of growth and nutrient dynamics in a disturbed mangrove forest, Indian River Lagoon, Florida

Science.gov (United States)

Feller, Ilka C.; Whigham, D.F.; McKee, K.L.; Lovelock, C.E.

2003-01-01

The objectives of this study were to determine effects of nutrient enrichment on plant growth, nutrient dynamics, and photosynthesis in a disturbed mangrove forest in an abandoned mosquito impoundment in Florida. Impounding altered the hydrology and soil chemistry of the site. In 1997, we established a factorial experiment along a tree-height gradient with three zones, i.e., fringe, transition, dwarf, and three fertilizer treatment levels, i.e., nitrogen (N), phosphorus (P), control, in Mosquito Impoundment 23 on the eastern side of Indian River. Transects traversed the forest perpendicular to the shoreline, from a Rhizophora mangle-dominated fringe through an Avicennia germinans stand of intermediate height, and into a scrub or dwarf stand of A. germinans in the hinterland. Growth rates increased significantly in response to N fertilization. Our growth data indicated that this site is N-limited along the tree-height gradient. After 2 years of N addition, dwarf trees resembled vigorously growing saplings. Addition of N also affected internal dynamics of N and P and caused increases in rates of photosynthesis. These findings contrast with results for a R. mangle-dominated forest in Belize where the fringe is N-limited, but the dwarf zone is P-limited and the transition zone is co-limited by N and P. This study demonstrated that patterns of nutrient limitation in mangrove ecosystems are complex, that not all processes respond similarly to the same nutrient, and that similar habitats are not limited by the same nutrient when different mangrove forests are compared.

Coolant circuit water chemistry of the Paks Nuclear Power Plant

International Nuclear Information System (INIS)

Tilky, Peter; Doma, Arpad

1985-01-01

The numerous advantages of the proper selection of water chemistry parameters including low corrosion rate of the structural materials, hence the low-level activity build-up, depositions, radiation doses were emphasized. Major characteristics of water chemistry applied to the primary coolant of pressurized water reactors including neutral, slightly basic and strong basic ones are discussed. Boric acid is widely used to control reactivity. Primary coolant water chemistry of WWER type reactors which is based on the addition of ammonia and potassium hydroxide to boric acid is compared with that of other reactors. The demineralization of the total condensate of the steam turbines became a general trend in the water chemistry of the secondary coolant circuits. (V.N.)

Nutrient synchrony in preruminant calves

NARCIS (Netherlands)

Borne, van den J.J.G.C.

2006-01-01

In animal nutrition, the nutrient composition of the daily feed supply is composed to match the nutrient requirements for the desired performance. The time of nutrient availability within a day is usually considered not to affect the fate of nutrients. The aim of this thesis was to evaluate effects

From hot atom chemistry to epithermal chemistry

International Nuclear Information System (INIS)

Roessler, K.

2004-01-01

The rise and fall of hot atom chemistry (HAC) over the years from 1934 to 2004 is reviewed. Several applications are discussed, in particular to astrophysics and the interaction of energetic ions and atoms in space. Epithermal chemistry (ETC) is proposed to substitute the old name, since it better fits the energy range as well as the non-thermal and non-equilibrium character of the reactions. ETC also avoids the strong connexion of HAC to nuclear chemistry and stands for the opening of the field to physical chemistry and astrophysics. (orig.)

Symposium on chemistry and biotechnology for national development. Proceedings

International Nuclear Information System (INIS)

Garba, A.; Ogunmola, G.B.

1998-01-01

This document is the full proceedings of the symposium on chemistry and biotechnology for national development held at SHESTCO in 1995. It contains the full texts of a forward, opening and special remarks, welcome and keynote addresses and abstracts and texts of 21 technical papers. The subjects covered included information technology,chemistry and biotechnology in agriculture, health care and industrial development. Additionally, the abstracts in respect of 19 other papers are included. We wish to thank the Coordinator of SHESTCO for making available this proceedings

Symposium on chemistry and biotechnology for national development. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Garba, A; Ogunmola, G B [eds.

1998-12-01

This document is the full proceedings of the symposium on chemistry and biotechnology for national development held at SHESTCO in 1995. It contains the full texts of a forward, opening and special remarks, welcome and keynote addresses and abstracts and texts of 21 technical papers. The subjects covered included information technology,chemistry and biotechnology in agriculture, health care and industrial development. Additionally, the abstracts in respect of 19 other papers are included. We wish to thank the Coordinator of SHESTCO for making available this proceedings.

Mathematical Chemistry

OpenAIRE

Trinajstić, Nenad; Gutman, Ivan

2002-01-01

A brief description is given of the historical development of mathematics and chemistry. A path leading to the meeting of these two sciences is described. An attempt is made to define mathematical chemistry, and journals containing the term mathematical chemistry in their titles are noted. In conclusion, the statement is made that although chemistry is an experimental science aimed at preparing new compounds and materials, mathematics is very useful in chemistry, among other things, to produc...

Chemistry of supramolecular systems containing porphyrins and metal complexes

OpenAIRE

Araki, Koiti; Toma, Henrique Eisi

2002-01-01

Supramolecular chemistry is expected to keep a high developing pace in the next years, giving support to the advancement of molecular devices and nanotechnology. In this sense, porphyrins and their analogues should play a significant role as a consequence of their catalytic, electrocatalytic, photochemical and photoelectrochemical properties. In this review we focused on our own strategy based on coordination chemistry for the design and build-up of supermolecules and supramolecular structure...

Nuclear chemistry counting facilities: requirements definition

International Nuclear Information System (INIS)

O'Brien, D.W.; Baker, J.

1979-01-01

In an effort to upgrade outdated instrumentation and to take advantage of current and imminent technologies the Nuclear Chemistry Division at Lawrence Livermore Laboratory is about to undertake a major upgrade of their low level radiation counting and analysis facilities. It is expected that such a project will make a more coordinated data acquisition and data processing system, reduce manual data handling operations and speed up data processing throughput. Before taking on a systems design it is appropriate to establish a definition of the requirements of the facilities. This report examines why such a project is necessary in the context of the current and projected operations, needs, problems, risks and costs. The authors also address a functional specification as a prelude to a system design and the design constraints implicit in the systems implementation. Technical, operational and economic assessments establish necessary boundary conditions for this discussion. This report also establishes the environment in which the requirements definition may be considered valid. The validity of these analyses is contingent on known and projected technical, scientific and political conditions

Spatially variable synergistic effects of disturbance and additional nutrients on kelp recruitment and recovery.

Science.gov (United States)

Carnell, Paul E; Keough, Michael J

2014-05-01

Understanding the impact of multiple stressors on ecosystems is of pronounced importance, particularly when one or more of those stressors is anthropogenic. Here we investigated the role of physical disturbance and increased nutrients on reefs dominated by the canopy-forming kelp Ecklonia radiata. We combined experimental kelp canopy removals and additional nutrient at three different locations in a large embayment in temperate southeastern Australia. Over the following winter recruitment season, Ecklonia recruitment was unaffected by increased nutrients alone, but tripled at all sites where the canopy had been removed. At one site, the combination of disturbance and increased nutrients resulted in more than four times the recruitment of the introduced kelp Undaria pinnatifida. Six months after disturbance, the proliferation of the Undaria canopy in the canopy-removal and nutrient-addition treatment negatively influenced the recovery of the native kelp Ecklonia. Given the otherwise competitive dominance of adult Ecklonia, this provides a mechanism whereby Undaria could maintain open space for the following recruitment season. This interplay between disturbance, nutrients and the response of native and invasive species makes a compelling case for how a combination of factors can influence species dynamics.

Chemistry of high temperature superconductors

CERN Document Server

1991-01-01

This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

Importance of Choline as Essential Nutrient and Its Role in Prevention of Various Toxicities

Directory of Open Access Journals (Sweden)

Somava Biswas

2015-01-01

Full Text Available Choline is a water-soluble essential nutrient included as a member of the vitamin B12 group owing to its structural similarities with that of the other members of the group. Its roles and functions, however, extend much wider than that of the vitamins with which it is grouped. Choline is vital for maintenance of various key metabolic processes which play a role in the prevention or progression of various health impairments. The occurrence of diseases like neural tube defect (NTD and Alzheimer’s is prevented by the metabolic role of choline. It is also indispensable for mitigation of various forms of toxic contamination. While adequate level of choline in the body is essential, an excess of choline can result in various forms of disorder. To maintain the optimal level of choline in the body can be a challenge. The vital roles played by choline together with the range of contradictions and problems that choline presents make choline an interesting area of study. This paper attempts to summarize and review some recent publications on choline that have opened up new prospect in understanding the multiple role played by choline and in throwing light on the role played by this wonder essential nutrient in mitigating various forms of toxic contamination.

Nematodes enhance plant growth and nutrient uptake under C and N-rich conditions

Science.gov (United States)

Gebremikael, Mesfin T.; Steel, Hanne; Buchan, David; Bert, Wim; de Neve, Stefaan

2016-09-01

The role of soil fauna in crucial ecosystem services such as nutrient cycling remains poorly quantified, mainly because of the overly reductionistic approach adopted in most experimental studies. Given that increasing nitrogen inputs in various ecosystems influence the structure and functioning of soil microbes and the activity of fauna, we aimed to quantify the role of the entire soil nematode community in nutrient mineralization in an experimental set-up emulating nutrient-rich field conditions and accounting for crucial interactions amongst the soil microbial communities and plants. To this end, we reconstructed a complex soil foodweb in mesocosms that comprised largely undisturbed native microflora and the entire nematode community added into defaunated soil, planted with Lolium perenne as a model plant, and amended with fresh grass-clover residues. We determined N and P availability and plant uptake, plant biomass and abundance and structure of the microbial and nematode communities during a three-month incubation. The presence of nematodes significantly increased plant biomass production (+9%), net N (+25%) and net P (+23%) availability compared to their absence, demonstrating that nematodes link below- and above-ground processes, primarily through increasing nutrient availability. The experimental set-up presented allows to realistically quantify the crucial ecosystem services provided by the soil biota.

Fruit and cereal bioactives: sources, chemistry, and applications

National Research Council Canada - National Science Library

Tokusoglu, Ozlem; Hall, Clifford, III

2011-01-01

"Presenting up-to-date data in an easy-to-use format, this comprehensive overview of the chemistry of bioactive components of fruits and cereals addresses the role of these compounds in determining...

The Nutrient Density of Snacks

Directory of Open Access Journals (Sweden)

Julie Hess BA

2017-03-01

Full Text Available Background: Although Americans receive almost a quarter of their daily energy from snacks, snacking remains a poorly defined and understood eating occasion. However, there is little dietary guidance about choosing snacks. Families, clinicians, and researchers need a comprehensive approach to assessing their nutritional value. Objective: To quantify and compare the nutrient density of commonly consumed snacks by their overall nutrient profiles using the Nutrient-Rich Foods (NRF Index 10.3. Methods: NRF Index scores were calculated for the top 3 selling products (based on 2014 market research data in different snack categories. These NRF scores were averaged to provide an overall nutrient-density score for each category. Results: Based on NRF scores, yogurt (55.3, milk (52.5, and fruit (30.1 emerged as the most nutrient-dense snacks. Ice cream (−4.4, pies and cakes (−11.1, and carbonated soft drinks (−17.2 emerged as the most nutrient-poor snacks. Conclusions: The NRF Index is a useful tool for assessing the overall nutritional value of snacks based on nutrients to limit and nutrients to encourage.

Synergistic effects of pCO2 and iron availability on nutrient consumption ratio of the Bering Sea phytoplankton community

Directory of Open Access Journals (Sweden)

K. Sugie

2013-10-01

Full Text Available Little is known concerning the effect of CO2 on phytoplankton ecophysiological processes under nutrient and trace element-limited conditions, because most CO2 manipulation experiments have been conducted under elements-replete conditions. To investigate the effects of CO2 and iron availability on phytoplankton ecophysiology, we conducted an experiment in September 2009 using a phytoplankton community in the iron limited, high-nutrient, low-chlorophyll (HNLC region of the Bering Sea basin . Carbonate chemistry was controlled by the bubbling of the several levels of CO2 concentration (180, 380, 600, and 1000 ppm controlled air, and two iron conditions were established, one with and one without the addition of inorganic iron. We demonstrated that in the iron-limited control conditions, the specific growth rate and the maximum photochemical quantum efficiency (Fv/Fm of photosystem (PS II decreased with increasing CO2 levels, suggesting a further decrease in iron bioavailability under the high-CO2 conditions. In addition, biogenic silica to particulate nitrogen and biogenic silica to particulate organic carbon ratios increased from 2.65 to 3.75 and 0.39 to 0.50, respectively, with an increase in the CO2 level in the iron-limited controls. By contrast, the specific growth rate, Fv/Fm values and elemental compositions in the iron-added treatments did not change in response to the CO2 variations, indicating that the addition of iron canceled out the effect of the modulation of iron bioavailability due to the change in carbonate chemistry. Our results suggest that high-CO2 conditions can alter the biogeochemical cycling of nutrients through decreasing iron bioavailability in the iron-limited HNLC regions in the future.

Soluble organic nutrient fluxes

Science.gov (United States)

Robert G. Qualls; Bruce L. Haines; Wayne Swank

2014-01-01

Our objectives in this study were (i) compare fluxes of the dissolved organic nutrients dissolved organic carbon (DOC), DON, and dissolved organic phosphorus (DOP) in a clearcut area and an adjacent mature reference area. (ii) determine whether concentrations of dissolved organic nutrients or inorganic nutrients were greater in clearcut areas than in reference areas,...

Changing Groundwater-Surface Water Interactions Impact Stream Chemistry and Ecology at the Arctic-Boreal Transition in Western Alaska

Science.gov (United States)

Koch, J. C.; Carey, M.; O'Donnell, J.; Sjoberg, Y.; Zimmerman, C. E.

2016-12-01

The arctic-boreal transition zone of Alaska is experiencing rapid change related to unprecedented warming and subsequent loss of permafrost. These changes in turn may affect groundwater-surface water (GW-SW) interactions, biogeochemical cycling, and ecosystem processes. While recent field and modeling studies have improved our understanding of hydrology in watersheds underlain by thawing permafrost, little is known about how these hydrologic shifts will impact bottom-up controls on stream food webs. To address this uncertainty, we are using an integrative experimental design to link GW-SW interactions to stream biogeochemistry and biota in 10 first-order streams in northwest Alaska. These study streams drain watersheds that span several gradients, including elevation, aspect, and vegetation (tundra vs. forest). We have developed a robust, multi-disciplinary data set to characterize GW-SW interactions and to mechanistically link GW-SW dynamics to water quality and the stream ecosystem. Data includes soil hydrology and chemistry; stream discharge, temperature, and inflow rates; water chemistry (including water isotopes, major ions, carbon concentration and isotopes, nutrients and chlorophyll-a), and invertebrate and fish communities. Stream recession curves indicate a decreasing rate later in the summer in some streams, consistent with seasonal thaw in lower elevation and south-facing catchments. Base cation and water isotope chemistry display similar impacts of seasonal thaw and also suggest the dominance of groundwater in many streams. Coupled with estimates of GW-SW exchange at point, reach, and catchment scales, these results will be used to predict how hydrology and water quality are likely to impact fish habitat and growth given continued warming at the arctic-boreal transition.

Implication of two in-stream processes in the fate of nutrients discharged by sewage system into a temporary river.

Science.gov (United States)

David, Arthur; Perrin, Jean-Louis; Rosain, David; Rodier, Claire; Picot, Bernadette; Tournoud, Marie-George

2011-10-01

The aim of this study was to better understand the fate of nutrients discharged by sewage treatment plants into an intermittent Mediterranean river, during a low-flow period. Many pollutants stored in the riverbed during the low-flow period can be transferred to the downstream environments during flood events. The study focused on two processes that affect the fate and the transport of nutrients, a physical process (retention in the riverbed sediments) and a biological process (denitrification). A spatial campaign was carried out during a low-flow period to characterize the nutrient contents of both water and sediments in the Vène River. The results showed high nutrient concentrations in the water column downstream of the treated wastewater disposal (up to 13,315 μg N/L for ammonium and 2,901 μg P/L for total phosphorus). Nutrient concentrations decreased rapidly downstream of the disposal whereas nutrient contents in the sediments increased (up to 1,898 and 784 μg/g for total phosphorus and Kjeldahl nitrogen, respectively). According to an in situ experiment using sediment boxes placed in the riverbed for 85 days, we estimated that the proportion of nutrients trapped in the sediments represents 25% (respectively 10%) of phosphorus (respectively nitrogen) loads lost from the water column. In parallel, laboratory tests indicated that denitrification occurred in the Vène River, and we estimated that denitrification likely coupled to nitrification processes during the 85 days of the experiment was significantly involved in the removal of nitrogen loads (up to 38%) from the water column and was greater than accumulation processes.

Characterization of major-ion chemistry and nutrients in headwater streams along the Appalachian National Scenic Trail and within adjacent watersheds, Maine to Georgia

Science.gov (United States)

Argue, Denise M.; Pope, Jason P.; Dieffenbach, Fred

2012-01-01

Appalachian Trail has the largest spatial area of high atmospheric acid deposition, the lower ionic strength waters in the northern and southern ecosections of the Appalachian Trail may have been more adversely affected by acid deposition. The low ionic strength of the streams in the White Mountains, Blue Ridge Mountains, and Allegheny Mountains ecosections makes parts of these regions susceptible to seasonal or event-driven episodic acidification, which can be detrimental to health of aquatic and terrestrial ecosystems. Median catchment ANC values were classified into three groups - acidic, sensitive, and insensitive. The White Mountains, Blue Ridge Mountains, and Allegheny Mountains ecosections included the highest frequency of catchments classified as acidic or sensitive. More than 56 percent of the catchments from the White Mountains ecosection were classified as sensitive to acidic inputs. In the Blue Ridge ecosection, 1.6 percent of the catchments were classified as acidic, and 38.2 percent of the catchments were classified as sensitive to acidic inputs. In the Allegheny Mountains ecosection, 17.6 percent of the catchments were classified as acidic, and 29.4 percent of the catchments were classified as sensitive to acidic inputs. Median concentrations of nitrogen species were less than 0.4 mg/L, and median concentrations of total phosphorus were less than 0.02 mg/L along the Appalachian Trail. A comparison of median catchment concentrations of nutrients to estimated national background concentrations demonstrated that concentrations along the Appalachian Trail are generally lower. A comparison of median concentrations of total nitrogen and total phosphorus to the U.S. Environmental Protection Agency's (USEPA) nutrient criteria for the Eastern U.S. ecoregions showed that the concentrations of total nitrogen in the northern section of the Appalachian Trail were generally higher than the USEPA criterion. Similarly, median concentrations of total phosphorus in the southern

Industrial chemistry engineering

International Nuclear Information System (INIS)

1993-01-01

This book on industrial chemistry engineering is divided in two parts. The first part deals with industrial chemistry, inorganic industrial chemistry, organic industrial chemistry, analytical chemistry and practical questions. The last parts explain the chemical industry, a unit parts and thermodynamics in chemical industry and reference. It reveals the test subjects for the industrial chemistry engineering with a written examination and practical skill.

Comparative efficacy of up to 50% partial fish meal replacement with fermented soybean meal or enzymatically prepared soybean meal on growth performance, nutrient digestibility and fecal microflora in weaned pigs.

Science.gov (United States)

Jeong, Jin Suk; Kim, In Ho

2015-06-01

This study was conducted to determine the comparative efficacy of partial fish meal (FM) replacement (up to 50%) with fermented soybean meal (FSBM; SoELAB, PepSoyGen and Soytide) or enzymatically prepared SBM (HP 300) on growth performance, nutrient digestibility and fecal microflora in weaned pigs. A total of 100 weaned pigs (body weight 6.59 ± 0.29 kg) were used in experimental feeding trials, lasting for up to 6 weeks, and were randomly allotted to five groups with four block replicates of five pigs per pen serving as one block. Dietary treatments were as follows: (i) 100% FM, (ii) 50% FM + 50% SoELAB-54, (iii) 50% FM + 50% PepSoyGen, (iv) 50% FM + 50% Soytide and (v) 50% FM + 50% HP 300. Concerning growth performance, none of the treated SBM preparations demonstrated any significantly different effect compared with FM treatment. With respect to nutrient digestibility, SoELAB and HP 300 treatments demonstrated no significant difference compared with FM treatment. Lastly, none of the SBM preparations demonstrated any significant differences in animal fecal score and all of the differentially treated SBM increased fecal Lactobacillus counts, while maintaining similar Escherichia coli counts compared with FM treatment. © 2014 Japanese Society of Animal Science.

Expert system for diagnostics and status monitoring of NPP water chemistry condition

International Nuclear Information System (INIS)

Shvedova, M.N.; Kritski, V.G.; Zakharova, S.V.; Benediktov, V.B.; Nikolaev, F.V.

2002-01-01

Water chemistry condition (WCC) has been the subject of constant study and improvement up to the present day. It is connected with the presence of a direct relationship between the violation of water chemistry regulation on the one hand and components reliability of the circuit's equipment and cost-effectiveness of their operation on the other. It dictates the necessity to apply different optimization methods in the field of monitoring and use of information analytical and diagnostic systems to assess WCC quality, control and support. LI ''VNIPIET'' employees have, for several years, been developing an expert diagnostic system for supporting WCC and status monitoring of RBMK - reactor NPPs [2]. This system has not only conveniently organized the traditional functions of information acquisition and storage, a complete presentation of information in the form of tables, graphs of a dynamical changes of parameters and formation regular reports, diagnostic functions and issuing recommendations on WCC correction, but it also allows the assessment of confidence in the diagnosis made, relying on a wide range of numerical estimates, which were calculated by the use of expert data, and to make a credible prediction of an existing situation development. (authors)

Permanent make-up colorants may cause severe skin reactions.

Science.gov (United States)

Wenzel, Sabrina M; Welzel, Julia; Hafner, Christian; Landthaler, Michael; Bäumler, Wolfgang

2010-10-01

In recent years, cosmetic tattoos [permanent make-up (PMU)] on eyelids, eyebrows and lips have become increasingly popular. However, most colorants are manufactured for non-medical purposes, without any established history of safe use in humans. To investigate severe adverse reactions, such as swelling, burning, and the development of papules, of the lips and the surrounding area in 4 patients who had had at least two PMU procedures on their lips. Adverse skin reactions were examined with patch and prick testing of the colorants. In addition, skin biopsies were taken in the centre of the prick test for histology. One patient declined prick testing. Beauticians tended to use various PMU products, but all contained Pigment Red 181 (CI 73360). All patients tested showed a clear delayed reaction to Pigment Red 181 or the tattoo ink, or both, after prick testing. Histology indicated an allergic reaction. Each lip lesion slowly abated after several months of topical or systemic therapy with steroids in combination with tacrolimus, but none has yet completely resolved. In light of the severe and often therapy-resistant skin reactions, we strongly recommend the regulation and control of the substances used in PMU colorants. © 2010 John Wiley & Sons A/S.

Chemistry: content, context and choices : towards students' higher order problem solving in upper secondary school

OpenAIRE

Broman, Karolina

2015-01-01

Chemistry is often claimed to be difficult, irrelevant, and uninteresting to school students. Even students who enjoy doing science often have problems seeing themselves as being scientists. This thesis explores and challenges the negative perception of chemistry by investigating upper secondary students’ views on the subject. Based on students’ ideas for improving chemistry education to make the subject more interesting and meaningful, new learning approaches rooted in context-based learning...

Evaluation of stream chemistry trends in US Geological Survey reference watersheds, 1970-2010.

Science.gov (United States)

Mast, M Alisa

2013-11-01

The Hydrologic Benchmark Network (HBN) is a long-term monitoring program established by the US Geological Survey in the 1960s to track changes in the streamflow and stream chemistry in undeveloped watersheds across the USA. Trends in stream chemistry were tested at 15 HBN stations over two periods (1970-2010 and 1990-2010) using the parametric Load Estimator (LOADEST) model and the nonparametric seasonal Kendall test. Trends in annual streamflow and precipitation chemistry also were tested to help identify likely drivers of changes in stream chemistry. At stations in the northeastern USA, there were significant declines in stream sulfate, which were consistent with declines in sulfate deposition resulting from the reductions in SO₂ emissions mandated under the Clean Air Act Amendments. Sulfate declines in stream water were smaller than declines in deposition suggesting sulfate may be accumulating in watershed soils and thereby delaying the stream response to improvements in deposition. Trends in stream chemistry at stations in other part of the country generally were attributed to climate variability or land disturbance. Despite declines in sulfate deposition, increasing stream sulfate was observed at several stations and appeared to be linked to periods of drought or declining streamflow. Falling water tables might have enhanced oxidation of organic matter in wetlands or pyrite in mineralized bedrock thereby increasing sulfate export in surface water. Increasing sulfate and nitrate at a station in the western USA were attributed to release of soluble salts and nutrients from soils following a large wildfire in the watershed.

Evaluation of stream chemistry trends in US Geological Survey reference watersheds, 1970-2010

Science.gov (United States)

Mast, M. Alisa

2013-01-01

The Hydrologic Benchmark Network (HBN) is a long-term monitoring program established by the US Geological Survey in the 1960s to track changes in the streamflow and stream chemistry in undeveloped watersheds across the USA. Trends in stream chemistry were tested at 15 HBN stations over two periods (1970–2010 and 1990–2010) using the parametric Load Estimator (LOADEST) model and the nonparametric seasonal Kendall test. Trends in annual streamflow and precipitation chemistry also were tested to help identify likely drivers of changes in stream chemistry. At stations in the northeastern USA, there were significant declines in stream sulfate, which were consistent with declines in sulfate deposition resulting from the reductions in SO2 emissions mandated under the Clean Air Act Amendments. Sulfate declines in stream water were smaller than declines in deposition suggesting sulfate may be accumulating in watershed soils and thereby delaying the stream response to improvements in deposition. Trends in stream chemistry at stations in other part of the country generally were attributed to climate variability or land disturbance. Despite declines in sulfate deposition, increasing stream sulfate was observed at several stations and appeared to be linked to periods of drought or declining streamflow. Falling water tables might have enhanced oxidation of organic matter in wetlands or pyrite in mineralized bedrock thereby increasing sulfate export in surface water. Increasing sulfate and nitrate at a station in the western USA were attributed to release of soluble salts and nutrients from soils following a large wildfire in the watershed.

Sensitivity analysis of a pulse nutrient addition technique for estimating nutrient uptake in large streams

Science.gov (United States)

Laurence Lin; J.R. Webster

2012-01-01

The constant nutrient addition technique has been used extensively to measure nutrient uptake in streams. However, this technique is impractical for large streams, and the pulse nutrient addition (PNA) has been suggested as an alternative. We developed a computer model to simulate Monod kinetics nutrient uptake in large rivers and used this model to evaluate the...

Towards Eco-reflexive Science Education. A Critical Reflection About Educational Implications of Green Chemistry

Science.gov (United States)

Sjöström, Jesper; Eilks, Ingo; Zuin, Vânia G.

2016-05-01

The modern world can be described as a globalized risk society. It is characterized by increasing complexity, unpredictable consequences of techno-scientific innovations and production, and its environmental consequences. Therefore, chemistry, just like many other knowledge areas, is in an ongoing process of environmentalization. For example, green chemistry has emerged as a new chemical metadiscipline and movement. The philosophy of green chemistry was originally based on a suggestion of twelve principles for environment-friendly chemistry research and production. The present article problematizes limitations in green chemistry when it comes to education. It argues that the philosophy of green chemistry in the context of education needs to be extended with socio-critical perspectives to form educated professionals and citizens who are able to understand the complexity of the world, to make value-based decisions, and to become able to engage more thoroughly in democratic decision-making on sustainability issues. Different versions of sustainability-oriented science/chemistry education are discussed to sharpen a focus on the most complex type, which is Bildung-oriented, focusing emancipation and leading to eco-reflexive education. The term eco- reflexive is used for a problematizing stance towards the modern risk society, an understanding of the complexity of life and society and their interactions, and a responsibility for individual and collective actions towards socio-ecojustice and global sustainability. The philosophical foundation and characteristics of eco-reflexive science education are sketched on in the article.

Primary water chemistry of VVERs-operating experience

International Nuclear Information System (INIS)

Kysela, Jan; Zmitko, Milan; Petrecky, Igor

1998-01-01

VVER units are operated in mixed boron-potassium-ammonia water chemistry. Several modifications of the water chemistry, differing in boron-potassium co-ordination and in the way how hydrogen concentration is produced and maintain in the coolant, is used. From the operational experience point of view VVER units do not show any significant problems connected with the primary coolant chemistry. The latest results indicate that dose rate levels are slowly returning to the former ones. An improvement of the radiation situation observed last two years is supported by the surface activity measurements. However, the final conclusion on the radiation situation can be made only after evaluation of the several following cycles. Further investigation is also needed to clarify a possible effect of modified water chemistry and shut-down chemistry on radioactivity build-up and dose rate level at Dukovany units. Structure materials composition has a significant effect on radiation situation in the units. It concerns mainly of cobalt content in SG material. There is no clear evidence of possible effect of the SG shut-down regimes on the radiation situation in the units even if the dose rate and surface activity data show wide spread for the individual reactor loops. (S.Y.)

Constitution and application of reactor make-up system's fault diagnostic Bayesian networks

International Nuclear Information System (INIS)

Liang Jie; Cai Qi; Chu Zhuli; Wang Haiping

2013-01-01

A fault diagnostic Bayesian network of reactor make-up system was constituted. The system's structure characters, operation rules and experts' experience were combined and an initial net was built. As the fault date sets were learned with the particle swarm optimization based Bayesian network structure, the structure of diagnostic net was completed and used to inference case. The built net can analyze diagnostic probability of every node in the net and afford assistant decision to fault diagnosis. (authors)

Chemistry of water and steam in power plants and related technologies. Glossary of terms and definitions English - German; German - English

Energy Technology Data Exchange (ETDEWEB)

Schmitz, H.P.; Teutenberg, U.

2006-07-01

This new edition of a technical dictionary is an evaluation of the technical terms found in the domestic and foreign literature and in information brochures of specialist firms, directives, guidelines, standards, etc. This dictionary contains more than 3,000 terms mainly with definitions with respect to the chemistry of water and steam in power plants along with the related types of water (untreated water, feedwater and boiler water, make-up water, waste water) and the water treatment processes (ion exchange, membrane process, etc.), water conditioning and chemical analysis, internal cleaning of steam generating plants (e.g. flushing, boiling-out, pre-operational and operational acid cleaning, steam blowing) as well as fundamentals of water chemistry. The technical knowledge of the authors, Heinz-Peter Schmitz, FDBR, with more than 25 years professional experience as translator/official in charge of documentation and Ulrich Teutenberg, Babcock/Hitachi with more than 30 years professional experience as senior consultant for water chemistry and commissioning is reflected in this dictionary. Part 1 contains the English-German version, Part 2 the German-English version. (orig.)

GEOS-5 Chemistry Transport Model User's Guide

Science.gov (United States)

Kouatchou, J.; Molod, A.; Nielsen, J. E.; Auer, B.; Putman, W.; Clune, T.

2015-01-01

The Goddard Earth Observing System version 5 (GEOS-5) General Circulation Model (GCM) makes use of the Earth System Modeling Framework (ESMF) to enable model configurations with many functions. One of the options of the GEOS-5 GCM is the GEOS-5 Chemistry Transport Model (GEOS-5 CTM), which is an offline simulation of chemistry and constituent transport driven by a specified meteorology and other model output fields. This document describes the basic components of the GEOS-5 CTM, and is a user's guide on to how to obtain and run simulations on the NCCS Discover platform. In addition, we provide information on how to change the model configuration input files to meet users' needs.

Current organic chemistry

National Research Council Canada - National Science Library

1997-01-01

Provides in depth reviews on current progress in the fields of asymmetric synthesis, organometallic chemistry, bioorganic chemistry, heterocyclic chemistry, natural product chemistry, and analytical...

Charles J. Pedersen's legacy to chemistry.

Science.gov (United States)

Izatt, Reed M

2017-05-09

The serendipitous discovery in 1961 of dibenzo-18-crown-6 by Charles J. Pedersen marked the beginning of research on cyclic polyether macrocyclic compounds. These compounds have a remarkably selective affinity for certain metal ions and provide a framework for studying molecular recognition processes. Pedersen's work excited much interest in the scientific community and fueled important advances in macrocyclic and supramolecular chemistry. Born in Korea of a Japanese mother and a Norwegian engineer father, he was educated in Japan and later graduated from the University of Dayton (BS, chemical engineering) and Massachusetts Institute of Technology (MS, chemistry). He worked at du Pont for 42 years as a research chemist. His research talent at du Pont earned him an appointment as a Research Associate allowing him to pursue research as he chose. This freedom served him well making it possible for him to devote all his efforts following his discovery of dibenzo-18-crown-6 until his retirement to synthesis of cyclic polyethers and evaluation of their metal ion complexation properties. His influence on macrocyclic and supramolecular chemistry has been pervasive. He was co-recipient of the 1987 Nobel Prize in chemistry for development and use of molecules with structure-specific interactions of high selectivity. The year 2017 marks the fiftieth anniversary of the publication of his first paper describing his synthesis of over 50 crown ethers.

Bioorthogonal chemistry: strategies and recent development

Science.gov (United States)

Ramil, Carlo P.; Lin, Qing

2013-01-01

The use of covalent chemistry to track biomolecules in their native environment—a focus of bioorthogonal chemistry—has received considerable interests recently among chemical biologists and organic chemists alike. To facilitate wider adoption of bioorthogonal chemistry in biomedical research, a central effort in the last few years has been focused on the optimization of a few known bioorthogonal reactions, particularly with respective to reaction kinetics improvement, novel genetic encoding systems, and fluorogenic reactions for bioimaging. During these optimizations, three strategies have emerged, including the use of ring strain for substrate activation in the cycloaddition reactions, the discovery of new ligands and privileged substrates for accelerated metal-catalysed reactions, and the design of substrates with pre-fluorophore structures for rapid “turn-on” fluorescence after selective bioorthogonal reactions. In addition, new bioorthogonal reactions based on either modified or completely unprecedented reactant pairs have been reported. Finally, increasing attention has been directed toward the development of mutually exclusive bioorthogonal reactions and their applications in multiple labeling of a biomolecule in cell culture. In this feature article, we wish to present the recent progress in bioorthogonal reactions through the selected examples that highlight the above-mentioned strategies. Considering increasing sophistication in bioorthogonal chemistry development, we strive to project several exciting opportunities where bioorthogonal chemistry can make a unique contribution to biology in near future. PMID:24145483

Aquatic Chemistry

International Nuclear Information System (INIS)

Kim, Dong Yeun; Kim, Oh Sik; Kim, Chang Guk; Park, Cheong Gil; Lee, Gwi Hyeon; Lee, Cheol Hui

1987-07-01

This book deals aquatic chemistry, which treats water and environment, chemical kinetics, chemical balance like dynamical characteristic, and thermodynamics, acid-base chemistry such as summary, definition, kinetics, and PH design for mixture of acid-base chemistry, complex chemistry with definition, and kinetics, precipitation and dissolution on summary, kinetics of precipitation and dissolution, and balance design oxidation and resolution with summary, balance of oxidation and resolution.

Combinatorial chemistry

DEFF Research Database (Denmark)

Nielsen, John

1994-01-01

An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds.......An overview of combinatorial chemistry is presented. Combinatorial chemistry, sometimes referred to as `irrational drug design,' involves the generation of molecular diversity. The resulting chemical library is then screened for biologically active compounds....

On being green: can flow chemistry help?

Science.gov (United States)

Ley, Steven V

2012-08-01

The principles of Green Chemistry are important but challenging drivers for most modern synthesis programs. To meet these challenges new flow chemistry tools are proving to be very effective by providing improved heat/mass transfer opportunities, lower solvent usage, less waste generation, hazardous compound containment, and the possibility of a 24/7 working regime. This machine-assisted approach can be used to effect repetitive or routine scale-up steps or when combined with reagent and scavenger cartridges, to achieve multi-step synthesis of complex natural products and pharmaceutical agents. Copyright © 2012 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

The role of water chemistry and geomorphic control in the presence of Didymosphenia geminata in Quebec

Science.gov (United States)

Gillis, C.; Gabor, R. S.; Cullis, J. D.; Ran, L.; Hassan, M. A.

2010-12-01

Didymosphenia geminata (didymo), an invasive diatom, was first officially observed and identified in the Matapedia River in Eastern Quebec in July 2006. This Atlantic salmon fishing river has several characteristics shown to favor didymo's ability to form thick, extensive benthic mats, including stable flow and oligotrophic nutrient conditions. Since the incursion, rapid colonization and inter-catchment transfer processes were observed, notably in surrounding watersheds on the Gaspé Peninsula as well as in northern New-Brunswick. All affected watersheds share favorable characteristics for didymo growth, including high light, low nutrient waters, and stable substrate. The nearby North Shore of the St. Lawrence, which also contains rivers with conditions that would favor didymo growth, has not yet shown didymo presence. This system provides a comparison to identify necessary parameters for didymo growth, with differences primarily due to geology-driven water chemistry. Pre-incursion water chemistry was compared between the two regions. Rivers in the region where didymo is present displayed a high alkalinity and corresponding higher pH, due to increases concentrations of magnesium and calcium, than rivers in regions where didymo has not appeared. Also, rivers with didymo show a lower amount of color-causing compounds, such as organic carbon, and clearer water, which supports the theory that high light levels encourage didymo growth. In addition to water chemistry, channel morphology, bed stability and flow patterns are also believed to be key elements in determining the presence of this benthic diatom. In 2007, channel morphology, bed texture, bankfull depth and width, local bed slope and didymo presence were surveyed on a 65 km stretch of the Matapedia River. Relative frequency of didymo presence showed that didymo blooms are most likely to appear in cobble-riffles than in any other morphologies. In fact, cobble riffles promote didymo establishment due to shallow

Forensic Chemistry

Science.gov (United States)

Bell, Suzanne

2009-07-01

Forensic chemistry is unique among chemical sciences in that its research, practice, and presentation must meet the needs of both the scientific and the legal communities. As such, forensic chemistry research is applied and derivative by nature and design, and it emphasizes metrology (the science of measurement) and validation. Forensic chemistry has moved away from its analytical roots and is incorporating a broader spectrum of chemical sciences. Existing forensic practices are being revisited as the purview of forensic chemistry extends outward from drug analysis and toxicology into such diverse areas as combustion chemistry, materials science, and pattern evidence.

Structural material anomaly detection system using water chemistry data

International Nuclear Information System (INIS)

Asakura, Yamato; Nagase, Makoto; Uchida, Shunsuke; Ohsumi, Katsumi.

1992-01-01

The concept of an advanced water chemistry diagnosis system for detection of anomalies and preventive maintenance of system components is proposed and put into a concrete form. Using the analogy to a medical inspection system, analyses of water chemistry change will make it possible to detect symptoms of anomalies in system components. Then, correlations between water chemistry change and anomaly occurrence in the components of the BWR primary cooling system are analyzed theoretically. These fragmentary correlations are organized and reduced to an algorithm for the on-line diagnosis system using on-line monitoring data, pH and conductivity. By using actual plant data, the on-line diagnosis model system is verified to be applicable for early and automatic finding of the anomaly cause and for timely supply of much diagnostic information to plant operators. (author)

Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

International Nuclear Information System (INIS)

Ryan, R.R.

1981-05-01

This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research

Chemistry-nuclear chemistry division. Progress report, October 1979-September 1980

Energy Technology Data Exchange (ETDEWEB)

Ryan, R.R. (comp.)

1981-05-01

This report presents the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, element migration and fixation, inorganic chemistry, isotope separation and analysis, atomic and molecular collisions, molecular spectroscopy, muonic x rays, nuclear cosmochemistry, nuclear structure and reactions, radiochemical separations, theoretical chemistry, and unclassified weapons research.

Measurements of canopy chemistry with 1992 AVIRIS data at Blackhawk Island and Harvard Forest

Science.gov (United States)

Martin, Mary E.; Aber, John D.

1993-01-01

The research described in this paper was designed to determine if high spectral resolution imaging spectrometer data can be used to measure the chemical composition of forest foliage, specifically nitrogen and lignin concentration. Information about the chemical composition of forest canopies can be used to determine nutrient cycling rates and carbon balances in forest ecosystems. This paper will describe the results relating data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) to field measured canopy chemistry at Blackhawk Island, WI and Harvard Forest, MA.

Learning from Multiple Classifier Systems: Perspectives for Improving Decision Making of QSAR Models in Medicinal Chemistry.

Science.gov (United States)

Pham-The, Hai; Nam, Nguyen-Hai; Nga, Doan-Viet; Hai, Dang Thanh; Dieguez-Santana, Karel; Marrero-Poncee, Yovani; Castillo-Garit, Juan A; Casanola-Martin, Gerardo M; Le-Thi-Thu, Huong

2018-02-09

Quantitative Structure - Activity Relationship (QSAR) modeling has been widely used in medicinal chemistry and computational toxicology for many years. Today, as the amount of chemicals is increasing dramatically, QSAR methods have become pivotal for the purpose of handling the data, identifying a decision, and gathering useful information from data processing. The advances in this field have paved a way for numerous alternative approaches that require deep mathematics in order to enhance the learning capability of QSAR models. One of these directions is the use of Multiple Classifier Systems (MCSs) that potentially provide a means to exploit the advantages of manifold learning through decomposition frameworks, while improving generalization and predictive performance. In this paper, we presented MCS as a next generation of QSAR modeling techniques and discuss the chance to mining the vast number of models already published in the literature. We systematically revisited the theoretical frameworks of MCS as well as current advances in MCS application for QSAR practice. Furthermore, we illustrated our idea by describing ensemble approaches on modeling histone deacetylase (HDACs) inhibitors. We expect that our analysis would contribute to a better understanding about MCS application and its future perspectives for improving the decision making of QSAR models. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

High-definition optical coherence tomography and reflectance confocal microscopy in the in vivo visualization of a reaction to permanent make-up.

Science.gov (United States)

Maier, T; Flaig, M J; Ruzicka, T; Berking, C; Pavicic, T

2015-03-01

After permanent make-up treatments, eczematous and granulomatous reactions may occur which need anti-inflammatory treatment. For the definite diagnosis oftentimes biopsies are recommended. In vivo imaging such as reflectance confocal microscopy (RCM) and high-definition optical coherence tomography (HD-OCT) has been successfully used in the non-invasive diagnosis of various dermatoses before. Here, we report on non-invasive imaging of a reaction towards permanent make-up in a 40-year-old woman by using HD-OCT and RCM. Both in HD-OCT and in RCM subepidermal pigment and granulomatous changes could be visualized and correlated with the histopathological findings. Regression of the lesions in response to topical steroids and intralesional injections of steroids and 5-fluorouracil is reported and treatment options are discussed. Non-invasive imaging techniques such as HD-OCT and RCM allow the visualization and localization of exogenous pigment and help in the evaluation of adverse reactions due to permanent make-up tattooing. © 2014 European Academy of Dermatology and Venereology.

The Brazilian medicinal chemistry from 1998 to 2008 in the Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters and European Journal of Medicinal Chemistry [A química medicinal brasileira de 1998 a 2008 nos periódicos Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters e European Journal of Medicinal Chemistry

OpenAIRE

Bárbara Vasconcellos da Silva; Renato Saldanha Bastos; Angelo da Cunha Pinto

2009-01-01

In this article we present the Brazilian publications, the research groups involved, the contributions per states and the main diseases studied from 1998 to 2008 in the following periodicals: Journal of Medicinal Chemistry, Bioorganic and Medicinal Chemistry, Bioorganic and Medicinal Chemistry Letters and European Journal of Medicinal Chemistry.

Covalent-Bond Formation via On-Surface Chemistry.

Science.gov (United States)

Held, Philipp Alexander; Fuchs, Harald; Studer, Armido

2017-05-02

In this Review article pioneering work and recent achievements in the emerging research area of on-surface chemistry is discussed. On-surface chemistry, sometimes also called two-dimensional chemistry, shows great potential for bottom-up preparation of defined nanostructures. In contrast to traditional organic synthesis, where reactions are generally conducted in well-defined reaction flasks in solution, on-surface chemistry is performed in the cavity of a scanning probe microscope on a metal crystal under ultrahigh vacuum conditions. The metal first acts as a platform for self-assembly of the organic building blocks and in many cases it also acts as a catalyst for the given chemical transformation. Products and hence success of the reaction are directly analyzed by scanning probe microscopy. This Review provides a general overview of this chemistry highlighting advantages and disadvantages as compared to traditional reaction setups. The second part of the Review then focuses on reactions that have been successfully conducted as on-surface processes. On-surface Ullmann and Glaser couplings are addressed. In addition, cyclodehydrogenation reactions and cycloadditions are discussed and reactions involving the carbonyl functionality are highlighted. Finally, the first examples of sequential on-surface chemistry are considered in which two different functionalities are chemoselectively addressed. The Review gives an overview for experts working in the area but also offers a starting point to non-experts to enter into this exciting new interdisciplinary research field. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The making of a mock-up

DEFF Research Database (Denmark)

Rosenqvist, Tanja Schultz; Heimdal, Elisabeth Jacobsen

2011-01-01

As part of a research project about user involvement in textile design we have carried out two Design:Labs (Binder & Brandt 2008) engaging different stakeholders in designing textile products for Danish hospital environments. In this paper we follow a mock-up session done as part of the second...

Potential of diatom consortium developed by nutrient enrichment for biodiesel production and simultaneous nutrient removal from waste water.

Science.gov (United States)

Marella, Thomas Kiran; Parine, Narasimha Reddy; Tiwari, Archana

2018-05-01

Because of the decreasing fossil fuel supply and increasing greenhouse gas (GHG) emissions, microalgae have been identified as a viable and sustainable feedstock for biofuel production. The major effect of the release of wastewater rich in organic compounds has led to the eutrophication of freshwater ecosystems. A combined approach of freshwater diatom cultivation with urban sewage water treatment is a promising solution for nutrient removal and biofuel production. In this study, urban wastewater from eutrophic Hussain Sagar Lake was used to cultivate a diatom algae consortium, and the effects of silica and trace metal enrichment on growth, nutrient removal, and lipid production were evaluated. The nano-silica-based micronutrient mixture Nualgi containing Si, Fe, and metal ions was used to optimize diatom growth. Respectively, N and P reductions of 95.1% and 88.9%, COD and BOD reductions of 91% and 51% with a biomass yield of 122.5 mg L -1  day -1 and lipid productivity of 37 mg L -1  day -1 were observed for cultures grown in waste water using Nualgi. Fatty acid profiles revealed 13 different fatty acids with slight differences in their percentage of dry cell weight (DCW) depending on enrichment level. These results demonstrate the potential of diatom algae grown in wastewater to produce feedstock for renewable biodiesel production. Enhanced carbon and excess nutrient utilization makes diatoms ideal candidates for co-processes such as CO 2 sequestration, biodiesel production, and wastewater phycoremediation.

THE EFFECT OF ROCK PHOSPHATE ON SOIL NUTRIENT DYNAM ...

African Journals Online (AJOL)

DEPT OF AGRICULTURAL ENGINEERING

INTRODUCTION. With the current ..... Table 4: Effect of treatment on dynamics of total nitrogen (%) from. 2004 to 2007 ..... areas in Ghana and constant plant nutrient up- take by the crop. ... maintenance of high organic matter levels in the top soil is ... productivity. The pH of the soil ..... and iron oxides of Oxisols from Ghana.

Trophic State Evolution and Nutrient Trapping Capacity in a Transboundary Subtropical Reservoir: A 25-Year Study.

Science.gov (United States)

Cunha, Davi Gasparini Fernandes; Benassi, Simone Frederigi; de Falco, Patrícia Bortoletto; Calijuri, Maria do Carmo

2016-03-01

Artificial reservoirs have been used for drinking water supply, other human activities, flood control and pollution abatement worldwide, providing overall benefits to downstream water quality. Most reservoirs in Brazil were built during the 1970s, but their long-term patterns of trophic status, water chemistry, and nutrient removal are still not very well characterized. We aimed to evaluate water quality time series (1985-2010) data from the riverine and lacustrine zones of the transboundary Itaipu Reservoir (Brazil/Paraguay). We examined total phosphorus and nitrogen, chlorophyll a concentrations, water transparency, and phytoplankton density to look for spatial and temporal trends and correlations with trophic state evolution and nutrient retention. There was significant temporal and spatial water quality variation (P water quality and structure of the reservoir were mainly affected by one internal force (hydrodynamics) and one external force (upstream cascading reservoirs). Nutrient and chlorophyll a concentrations tended to be lower in the lacustrine zone and decreased over the 25-year timeframe. Reservoir operational features seemed to be limiting primary production and phytoplankton development, which exhibited a maximum density of 6050  org/mL. The relatively small nutrient concentrations in the riverine zone were probably related to the effect of the cascade reservoirs upstream of Itaipu and led to relatively low removal percentages. Our study suggested that water quality problems may be more pronounced immediately after the filling phase of the artificial reservoirs, associated with the initial decomposition of drowned vegetation at the very beginning of reservoir operation.

The Assystem firm turns to chemistry and pharmacy

International Nuclear Information System (INIS)

Anon.

2002-01-01

Controlling at 38% by Cogema and at 30% by the 'Dominique Louis' holding company, the Assystem firm makes nowadays use of its abilities for the chemistry and pharmacy sectors. The rehabilitation of the hazard studies in the chemical industry is more than never a topical question. (O.M.)

Modeling emissions for three-dimensional atmospheric chemistry transport models.

Science.gov (United States)

Matthias, Volker; Arndt, Jan A; Aulinger, Armin; Bieser, Johannes; Denier Van Der Gon, Hugo; Kranenburg, Richard; Kuenen, Jeroen; Neumann, Daniel; Pouliot, George; Quante, Markus

2018-01-24

Poor air quality is still a threat for human health in many parts of the world. In order to assess measures for emission reductions and improved air quality, three-dimensional atmospheric chemistry transport modeling systems are used in numerous research institutions and public authorities. These models need accurate emission data in appropriate spatial and temporal resolution as input. This paper reviews the most widely used emission inventories on global and regional scale and looks into the methods used to make the inventory data model ready. Shortcomings of using standard temporal profiles for each emission sector are discussed and new methods to improve the spatio-temporal distribution of the emissions are presented. These methods are often neither top-down nor bottom-up approaches but can be seen as hybrid methods that use detailed information about the emission process to derive spatially varying temporal emission profiles. These profiles are subsequently used to distribute bulk emissions like national totals on appropriate grids. The wide area of natural emissions is also summarized and the calculation methods are described. Almost all types of natural emissions depend on meteorological information, which is why they are highly variable in time and space and frequently calculated within the chemistry transport models themselves. The paper closes with an outlook for new ways to improve model ready emission data, for example by using external databases about road traffic flow or satellite data to determine actual land use or leaf area. In a world where emission patterns change rapidly, it seems appropriate to use new types of statistical and observational data to create detailed emission data sets and keep emission inventories up-to-date. Emission data is probably the most important input for chemistry transport model (CTM) systems. It needs to be provided in high temporal and spatial resolution and on a grid that is in agreement with the CTM grid. Simple

Water chemistry at RBMK plants: Problems and solutions

International Nuclear Information System (INIS)

Mamet, V.; Yurmanov, V.

2002-01-01

After around 15 years of operation RBMK-1000 units undergo a major refit, which includes safety system upgrading, fuel tube replacement, etc. The above upgrading has created problems for water chemistry. In particular, in late 80's in-core insertion time of the portion of control rods was reduced 10-fold thanks to a transfer from water to filming cooling of scram channels. Scram channels are cooled with inner surface water film cooling and nitrogen is injected into heads via special pipelines. Such cooling system modernization ensures fast insertion of absorber rods. The above upgrade intensified nitric acid radiolytic generation in water coolant and pH 25 value shift to acid conditions (up to 4.5). The results of corrosion tests in such conditions proved the necessity to improve water chemistry to ensure corrosion protection of scram/control rod and circuit components, especially those made out of aluminium alloy. Since 1990 the new revision of the RBMK-1000 water chemistry standard specified the new normal operational limit and action levels for possible temporary deviations of pH 25 value. RBMK plant specific measures were implemented at RBMK plants to meet the above requirements of the 1990 revision of the RBMK-1000 water chemistry standard. Clean-up systems of the above circuit were upgraded to ensure intensive absorption of nitric acid from water and pH 25 maintenance in a slightly acid area. (authors)

Water chemistry at RBMK plants: Problems and solutions

Energy Technology Data Exchange (ETDEWEB)

Mamet, V.; Yurmanov, V. [VNIIAES (Russian Federation)

2002-07-01

After around 15 years of operation RBMK-1000 units undergo a major refit, which includes safety system upgrading, fuel tube replacement, etc. The above upgrading has created problems for water chemistry. In particular, in late 80's in-core insertion time of the portion of control rods was reduced 10-fold thanks to a transfer from water to filming cooling of scram channels. Scram channels are cooled with inner surface water film cooling and nitrogen is injected into heads via special pipelines. Such cooling system modernization ensures fast insertion of absorber rods. The above upgrade intensified nitric acid radiolytic generation in water coolant and pH{sub 25} value shift to acid conditions (up to 4.5). The results of corrosion tests in such conditions proved the necessity to improve water chemistry to ensure corrosion protection of scram/control rod and circuit components, especially those made out of aluminium alloy. Since 1990 the new revision of the RBMK-1000 water chemistry standard specified the new normal operational limit and action levels for possible temporary deviations of pH{sub 25} value. RBMK plant specific measures were implemented at RBMK plants to meet the above requirements of the 1990 revision of the RBMK-1000 water chemistry standard. Clean-up systems of the above circuit were upgraded to ensure intensive absorption of nitric acid from water and pH{sub 25} maintenance in a slightly acid area. (authors)

Carbon Stable Isotope Values in Plankton and Mussels Reflect Changes in Carbonate Chemistry Associated with Nutrient Enhanced Net Production

Science.gov (United States)

Coastal ecosystems are inherently complex and potentially adaptive as they respond to changes in nutrient loads and climate. We documented the role that carbon stable isotope (δ13C) measurements could play in understanding that adaptation with a series of three Ecostat (i.e...

Bad chemistry

OpenAIRE

Petsko, Gregory A

2004-01-01

General chemistry courses haven't changed significantly in forty years. Because most basic chemistry students are premedical students, medical schools have enormous influence and could help us start all over again to create undergraduate chemistry education that works.

AutoClickChem: click chemistry in silico.

Directory of Open Access Journals (Sweden)

Jacob D Durrant

Full Text Available Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

AutoClickChem: click chemistry in silico.

Science.gov (United States)

Durrant, Jacob D; McCammon, J Andrew

2012-01-01

Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

Selecting automation for the clinical chemistry laboratory.

Science.gov (United States)

Melanson, Stacy E F; Lindeman, Neal I; Jarolim, Petr

2007-07-01

Laboratory automation proposes to improve the quality and efficiency of laboratory operations, and may provide a solution to the quality demands and staff shortages faced by today's clinical laboratories. Several vendors offer automation systems in the United States, with both subtle and obvious differences. Arriving at a decision to automate, and the ensuing evaluation of available products, can be time-consuming and challenging. Although considerable discussion concerning the decision to automate has been published, relatively little attention has been paid to the process of evaluating and selecting automation systems. To outline a process for evaluating and selecting automation systems as a reference for laboratories contemplating laboratory automation. Our Clinical Chemistry Laboratory staff recently evaluated all major laboratory automation systems in the United States, with their respective chemistry and immunochemistry analyzers. Our experience is described and organized according to the selection process, the important considerations in clinical chemistry automation, decisions and implementation, and we give conclusions pertaining to this experience. Including the formation of a committee, workflow analysis, submitting a request for proposal, site visits, and making a final decision, the process of selecting chemistry automation took approximately 14 months. We outline important considerations in automation design, preanalytical processing, analyzer selection, postanalytical storage, and data management. Selecting clinical chemistry laboratory automation is a complex, time-consuming process. Laboratories considering laboratory automation may benefit from the concise overview and narrative and tabular suggestions provided.

Protein Redox Dynamics During Light-to-Dark Transitions in Cyanobacteria and Impacts Due to Nutrient Limitation

Directory of Open Access Journals (Sweden)

Aaron T Wright

2014-07-01

Full Text Available Protein redox chemistry constitutes a major void in knowledge pertaining to photoautotrophic system regulation and signaling processes. We have employed a chemical biology approach to analyze redox sensitive proteins in live Synechococcus sp. PCC 7002 cells in both light and dark periods, and to understand how cellular redox balance is disrupted during nutrient perturbation. The present work identified 300 putative redox-sensitive proteins that are involved in the generation of reductant, macromolecule synthesis, and carbon flux through central metabolic pathways, and may be involved in cell signaling and response mechanisms. Furthermore, our research suggests that dynamic redox changes in response to specific nutrient limitations, including carbon and nitrogen limitations, contribute to the regulatory changes driven by a shift from light to dark. Taken together, these results contribute to a high-level understanding of post-translational mechanisms regulating flux distributions and suggest potential metabolic engineering targets for redirecting carbon towards biofuel precursors.

The impact of agricultural land use on stream chemistry in the Middle Hills of the Himalayas, Nepal

Science.gov (United States)

Collins, Robert; Jenkins, Alan

1996-11-01

The chemistry of streams draining agricultural and forested catchments in the Middle Hills of Nepal is described. Differences between mean streamwater chemistry are attributable to the effects of the terraced agriculture and land management practices. The agricultural catchments were found to exhibit higher mean concentrations of base cations (Na, Mg, K), bicarbonate, acid anions (SO 4, Cl), metals (Al, Fe) and nutrients (NO 3, PO 4). Increased base cations apparently result from tillage practices exposing fresh soil material to weathering. Increased acid anions result from inputs of inorganic fertiliser, notably ammonium sulphate, and from an apparent increase in evapotranspiration from the flooded terraces in the agricultural catchments. Increased metal concentrations may be promoted by increased weathering and erosion rates, and this is further supported by observations of dramatically higher turbidity in the streamwater draining the agricultural catchments. Higher levels of nutrients are the direct result of fertiliser input but concentrations are generally low from all catchments as a result of denitrification, indicating that eutrophication downstream is not a likely consequence of land use change. The major dynamics of water chemistry occur during the monsoon, which is also the main season for agricultural production. Mean wet season concentrations of base cations tend to be lower than in the dry season at all catchments as higher flow dilutes the relatively constant weathering input. Ammonium concentrations are higher from the agricultural catchments in the wet season as a result of direct washout of fertiliser. Detailed monitoring through storm periods at one agricultural catchment indicates that the chemistry responds very rapidly to changing flow, with cations decreasing and acid anions increasing followed by equally rapid recovery as flow recedes. Bicarbonate concentrations also decline markedly but are still sufficiently high to maintain pH near

Positronium chemistry

CERN Document Server

Green, James

1964-01-01

Positronium Chemistry focuses on the methodologies, reactions, processes, and transformations involved in positronium chemistry. The publication first offers information on positrons and positronium and experimental methods, including mesonic atoms, angular correlation measurements, annihilation spectra, and statistical errors in delayed coincidence measurements. The text then ponders on positrons in gases and solids. The manuscript takes a look at the theoretical chemistry of positronium and positronium chemistry in gases. Topics include quenching, annihilation spectrum, delayed coincidence

Nutrient sequestration in Aquitaine lakes (SW France) limits nutrient flux to the coastal zone

Science.gov (United States)

Buquet, Damien; Anschutz, Pierre; Charbonnier, Céline; Rapin, Anne; Sinays, Rémy; Canredon, Axel; Bujan, Stéphane; Poirier, Dominique

2017-12-01

Oligotrophic coastal zones are disappearing from increased nutrient loading. The quantity of nutrients reaching the coast is determined not only by their original source (e.g. fertilizers used in agriculture, waste water discharges) and the land use, but also by the pathways through which nutrients are cycled from the source to the river mouth. In particular, lakes sequester nutrients and, hence, reduce downstream transfer of nutrients to coastal environments. Here, we quantify the impact of Aquitaine great lakes on the fluxes of dissolved macro-nutrients (N, P, Si) to the Bay of Biscay. For that, we have measured nutrient concentrations and fluxes in 2014 upstream and downstream lakes of Lacanau and Carcans-Hourtin, which belongs to the catchment of the Arcachon Bay, which is the largest coastal lagoon of the Bay of Biscay French coast. Data were compared to values obtained from the Leyre river, the main freshwater and nutrient source for the lagoon. Results show that processes in lakes greatly limit nutrient flux to the lagoon compared to fluxes from Leyre river, although the watershed is similar in terms of land cover. In lakes, phosphorus and silicon are trapped for long term in the sediment, silicon as amorphous biogenic silica and phosphorus as organic P and P associated with Fe-oxides. Nitrogen that enters lakes mostly as nitrate is used for primary production. N is mineralized in the sediment; a fraction diffuses as ammonium. N2 production through benthic denitrification extracts only 10% of dissolved inorganic nitrogen from the aquatic system. The main part is sequestered in organic-rich sediment that accumulates below 5 m depth in both lakes.

High-Throughput Synthetic Chemistry Enabled by Organic Solvent Disintegrating Tablet.

Science.gov (United States)

Li, Tingting; Xu, Lei; Xing, Yanjun; Xu, Bo

2017-01-17

Synthetic chemistry remains a time- and labor-intensive process of inherent hazardous nature. Our organic solvent disintegrating tablet (O-Tab) technology has shown potential to make industrial/synthetic chemistry more efficient. As is the case with pharmaceutical tablets, our reagent-containing O-Tabs are mechanically strong, but disintegrate rapidly when in contact with reaction media (organic solvents). For O-Tabs containing sensitive chemicals, they can be further coated to insulate them from air and moisture. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Morphology-dependent water budgets and nutrient fluxes in arctic thaw ponds

Science.gov (United States)

Koch, Joshua C.; Gurney, Kirsty; Wipfli, Mark S.

2014-01-01

Thaw ponds on the Arctic Coastal Plain of Alaska are productive ecosystems, providing habitat and food resources for many fish and bird species. Permafrost in this region creates unique pond morphologies: deep troughs, shallow low-centred polygons (LCPs) and larger coalescent ponds. By monitoring seasonal trends in pond volume and chemistry, we evaluated whether pond morphology and size affect water temperature and desiccation, and nitrogen (N) and phosphorus (P) fluxes. Evaporation was the largest early-summer water flux in all pond types. LCPs dried quickly and displayed high early-summer nutrient concentrations and losses. Troughs consistently received solute-rich subsurface inflows, which accounted for 12 to 42 per cent of their volume and may explain higher P in the troughs. N to P ratios increased and ammonium concentrations decreased with pond volume, suggesting that P and inorganic N availability may limit ecosystem productivity in older, larger ponds. Arctic summer temperatures will likely increase in the future, which may accelerate mid-summer desiccation. Given their morphology, troughs may remain wet, become warmer and derive greater nutrient loads from their thawing banks. Overall, seasonal- to decadal-scale warming may increase ecosystem productivity in troughs relative to other Arctic Coastal Plain ponds. 

Particle water and pH in the Eastern Mediterranean: sources variability and implications for nutrients availability

Science.gov (United States)

Nikolaou, P.; Bougiatioti, A.; Stavroulas, I.; Kouvarakis, G.; Nenes, A.; Weber, R.; Kanakidou, M.; Mihalopoulos, N.

2015-10-01

Particle water (LWC) and aerosol pH drive the aerosol phase, heterogeneous chemistry and bioavailability of nutrients that profoundly impact cloud formation, atmospheric composition and atmospheric fluxes of nutrients to ecosystems. Few measurements of in-situ LWC and pH however exist in the published literature. Using concurrent measurements of aerosol chemical composition, cloud condensation nuclei activity and tandem light scattering coefficients, the particle water mass concentrations associated with the aerosol inorganic (Winorg) and organic (Worg) components are determined for measurements conducted at the Finokalia atmospheric observation station in the eastern Mediterranean between August and November 2012. These data are interpreted using the ISORROPIA-II thermodynamic model to predict pH of aerosols originating from the various sources that influence air quality in the region. On average, closure between predicted aerosol water and that determined by comparison of ambient with dry light scattering coefficients was achieved to within 8 % (slope = 0.92, R2 = 0.8, n = 5201 points). Based on the scattering measurements a parameterization is also derived, capable of reproducing the hygroscopic growth factor (f(RH)) within 15 % of the measured values. The highest aerosol water concentrations are observed during nighttime, when relative humidity is highest and the collapse of the boundary layer increases the aerosol concentration. A significant diurnal variability is found for Worg with morning and afternoon average mass concentrations being 10-15 times lower than nighttime concentrations, thus rendering Winorg the main form of particle water during daytime. The average value of total aerosol water was 2.19 ± 1.75 μg m-3, contributing on average up to 33 % of the total submicron mass concentration. Average aerosol water associated with organics, Worg, was equal to 0.56 ± 0.37 μg m-3, thus organics contributed about 27.5 % to the total aerosol water, mostly

Particle water and pH in the eastern Mediterranean: source variability and implications for nutrient availability

Science.gov (United States)

Bougiatioti, Aikaterini; Nikolaou, Panayiota; Stavroulas, Iasonas; Kouvarakis, Giorgos; Weber, Rodney; Nenes, Athanasios; Kanakidou, Maria; Mihalopoulos, Nikolaos

2016-04-01

Particle water (liquid water content, LWC) and aerosol pH are important parameters of the aerosol phase, affecting heterogeneous chemistry and bioavailability of nutrients that profoundly impact cloud formation, atmospheric composition, and atmospheric fluxes of nutrients to ecosystems. Few measurements of in situ LWC and pH, however, exist in the published literature. Using concurrent measurements of aerosol chemical composition, cloud condensation nuclei activity, and tandem light scattering coefficients, the particle water mass concentrations associated with the aerosol inorganic (Winorg) and organic (Worg) components are determined for measurements conducted at the Finokalia atmospheric observation station in the eastern Mediterranean between June and November 2012. These data are interpreted using the ISORROPIA-II thermodynamic model to predict the pH of aerosols originating from the various sources that influence air quality in the region. On average, closure between predicted aerosol water and that determined by comparison of ambient with dry light scattering coefficients was achieved to within 8 % (slope = 0.92, R2 = 0.8, n = 5201 points). Based on the scattering measurements, a parameterization is also derived, capable of reproducing the hygroscopic growth factor (f(RH)) within 15 % of the measured values. The highest aerosol water concentrations are observed during nighttime, when relative humidity is highest and the collapse of the boundary layer increases the aerosol concentration. A significant diurnal variability is found for Worg with morning and afternoon average mass concentrations being 10-15 times lower than nighttime concentrations, thus rendering Winorg the main form of particle water during daytime. The average value of total aerosol water was 2.19 ± 1.75 µg m-3, contributing on average up to 33 % of the total submicron mass concentration. Average aerosol water associated with organics, Worg, was equal to 0.56 ± 0.37 µg m-3; thus, organics

Nighttime NOx Chemistry in Coal-Fired Power Plant Plumes

Science.gov (United States)

Fibiger, D. L.; McDuffie, E. E.; Dube, W. P.; Veres, P. R.; Lopez-Hilfiker, F.; Lee, B. H.; Green, J. R.; Fiddler, M. N.; Ebben, C. J.; Sparks, T.; Weinheimer, A. J.; Montzka, D.; Campos, T. L.; Cohen, R. C.; Bililign, S.; Holloway, J. S.; Thornton, J. A.; Brown, S. S.

2015-12-01

Nitrogen oxides (NOx = NO + NO2) play a key role in atmospheric chemistry. During the day, they catalyze ozone (O3) production, while at night they can react to form nitric acid (HNO3) and nitryl chloride (ClNO2) and remove O3 from the atmosphere. These processes are well studied in the summer, but winter measurements are more limited. Coal-fired power plants are a major source of NOx to the atmosphere, making up approximately 30% of emissions in the US (epa.gov). NOx emissions can vary seasonally, as well as plant-to-plant, with important impacts on the details of the plume chemistry. In particular, due to inefficient plume dispersion, nighttime NOx emissions from power plants are held in concentrated plumes, where rates of mixing with ambient O3 have a strong influence on plume evolution. We will show results from the aircraft-based WINTER campaign over the northeastern United States, where several nighttime intercepts of power plant plumes were made. Several of these intercepts show complete O3 titration, which can have a large influence on NOx lifetime, and thus O3 production, in the plume. When power plant NO emissions exceed background O3 levels, O3 is completely consumed converting NO to NO2. In the presence of O3, NO2 will be oxidized to NO3, which will then react with NO2 to form N2O5, which can then form HNO3 and/or ClNO2 and, ultimately, remove NOx from the atmosphere or provide next-day oxidant sources. If there is no O3 present, however, no further chemistry can occur and NO and NO2 will be transported until mixing with sufficient O3 for higher oxidation products. Modeling results of plume development and mixing, which can tell us more about this transport, will also be presented.

Chemistry in production of heavy water and industrial solvents

International Nuclear Information System (INIS)

Thomas, P.G.

2015-01-01

Industries are the temples of modern science built on the robust foundation of science and technology. The genesis of giant chemical industries is from small laboratories where the scientific thoughts are fused and transformed into innovative technologies Heavy water production is an energy intensive giant chemical industry where various hazardous and flammable chemicals are handled, extreme operating conditions are maintained and various complex chemical reactions are involved. Chemistry is the back bone to all chemical industrial activities and plays a lead role in heavy water production also. Heavy Water Board has now mastered the technology of design, construction, operation and maintenance of Heavy Water plants as well as fine tuning of the process make it more cost effective and environment friendly. Heavy Water Board has ventured into diversified activities intimately connected with our three stages of Nuclear Power Programme. Process development for the production of nuclear grade solvents for the front end and back end of our nuclear fuel cycle is one area where we have made significant contributions. Heavy Water Board has validated, modified and fine-tuned the synthesis routes for TBP, D2EHPA, TOPO, TAPO TIAP, DNPPA, D2EHPA-II, DHOA etc and these solvents were accepted by end users. Exclusive campaigns were carried out in laboratory scale, bench scale and pilot plant scale before scaling up to industrial scale. The process chemistry is understood very well and chemical parameters were monitored in every step of the synthesis. It is a continual improvement cycle where fine tuning is carried out for best quality and yield of product at lowest cost. In this presentation, an attempt is made to highlight the role of chemistry in the production of Heavy Water and industrial solvents

Non-thermally activated chemistry

International Nuclear Information System (INIS)

Stiller, W.

1987-01-01

The subject is covered under the following headings: state-of-the art of non-thermally activated chemical processes; basic phenomena in non-thermal chemistry including mechanochemistry, photochemistry, laser chemistry, electrochemistry, photo-electro chemistry, high-field chemistry, magneto chemistry, plasma chemistry, radiation chemistry, hot-atom chemistry, and positronium and muonium chemistry; elementary processes in non-thermal chemistry including nuclear chemistry, interactions of electromagnetic radiations, electrons and heavy particles with matter, ionic elementary processes, elementary processes with excited species, radicalic elementary processes, and energy-induced elementary processes on surfaces and interfaces; and comparative considerations. An appendix with historical data and a subject index is given. 44 figs., 41 tabs., and 544 refs

SATLC applications as examples for systemic chemistry education ...

African Journals Online (AJOL)

It is also used as a vehicle to engage the students in a deep learning that focuses on relating ideas and making connection between new and prior knowledge. As applications of SATLC I present here systemic chemistry related units experimented in Egyptian secondary schools and universities with examples on systemic ...

Multiple perspectives on students’ scientific communication & reasoning in chemistry education [VISIONS 2011: Teaching

Directory of Open Access Journals (Sweden)

Maik Walpuski

2012-07-01

Full Text Available Both students and teachers need different competences for scientific reasoning. Apart from the required content knowledge and the ability of using it adequately, both groups need elaborated knowledge of strategies for decision-making and argumentation. These competences concerning decision-making are highly dependent on how frequently students are given the chance to argue in science classes. This article pools the results of three different research projects in chemistry education which focus on these three aspects: Students’ competences, the classroom situation with regard to communication and reasoning and teachers’ competences. Students’ skills needed for discussing chemistry content and for decision-making in scientific contexts are analyzed first. Following this, the opportunities for improving these skills during science lessons are researched and related to results from a study of teachers’ pedagogical content knowledge (PCK in this domain. The analysis of students’ and teachers’ communication skills is conducted in two different ways which are paper-pencil tests and video analysis. Paper-pencil tests are used to assess students’ performance in reasoning. The test items deal with chemistry-specific situations, including opportunities for decision-making, which are typical of socio-scientific issues (study 1. The study shows that students’ decision-making skills are poor when the topics deal with scientific contexts, but that students perform better when dealing with everyday-life contexts. One reason might be the lack of reasoning in chemistry lessons, as shown by a video study conducted in chemistry classes. Students’ and teachers’ in-class behavior and communication patterns are analyzed with regard to students’ and teachers’ contributions (study 2. The amount and the quality of students’ and teachers’ statements as well as the interactions, especially teachers’ reactions to students’ statements are

Nutrient Management in Recirculating Hydroponic Culture

Science.gov (United States)

Bugbee, Bruce

2004-01-01

There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

Green chemistry: A tool in Pharmaceutical Chemistry

OpenAIRE

Smita Talaviya; Falguni Majumdar

2012-01-01

Green chemistry expresses an area of research developing from scientific discoveries about pollution awareness and it utilizes a set of principles that reduces or eliminates the use or generation of hazardous substances in all steps of particular synthesis or process. Chemists and medicinal scientists can greatly reduce the risk to human health and the environment by following all the valuable principles of green chemistry. The most simple and direct way to apply green chemistry in pharmaceut...

Implementing and Operating Computer Graphics in the Contemporary Chemistry Education

Directory of Open Access Journals (Sweden)

Olga Popovska

2017-11-01

Full Text Available Technology plays a crucial role in modern teaching, providing both, educators and students fundamental theoretical insights as well as supporting the interpretation of experimental data. In the long term it gives students a clear stake in their learning processes. Advancing in education furthermore largely depends on providing valuable experiences and tools throughout digital and computer literacy. Here and after, the computer’s benefit makes no exception in the chemistry as a science. The major part of computer revolutionizing in the chemistry laboratory is with the use of images, diagrams, molecular models, graphs and specialized chemistry programs. In the sense of this, the teacher provides more interactive classes and numerous dynamic teaching methods along with advanced technology. All things considered, the aim of this article is to implement interactive teaching methods of chemistry subjects using chemistry computer graphics. A group of students (n = 30 at the age of 18–20 were testing using methods such as brainstorming, demonstration, working in pairs, and writing laboratory notebooks. The results showed that demonstration is the most acceptable interactive method (95%. This article is expected to be of high value to teachers and researchers of chemistry, implementing interactive methods, and operating computer graphics.

Performance test of nutrient control equipment for hydroponic plants

Science.gov (United States)

Rahman, Nurhaidar; Kuala, S. I.; Tribowo, R. I.; Anggara, C. E. W.; Susanti, N. D.

2017-11-01

Automatic control equipment has been made for the nutrient content in irrigation water for hydroponic plants. Automatic control equipment with CCT53200E conductivity controller to nutrient content in irrigation water for hydroponic plants, can be used to control the amount of TDS of nutrient solution in the range of TDS numbers that can be set according to the range of TDS requirements for the growth of hydroponically cultivated crops. This equipment can minimize the work time of hydroponic crop cultivators. The equipment measurement range is set between 1260 ppm up to 1610 ppm for spinach plants. Caisim plants were included in this experiment along with spinach plants with a spinach plants TDS range. The average of TDS device is 1450 ppm, while manual (conventional) is 1610 ppm. Nutrient solution in TDS controller has pH 5,5 and temperature 29,2 °C, while manual is pH 5,6 and temperature 31,3 °C. Manually treatment to hydroponic plant crop, yields in an average of 39.6 grams/plant, greater than the yield of spinach plants with TDS control equipment, which is in an average of 24.6 grams / plant. The yield of caisim plants by manual treatment is in an average of 32.3 grams/crop, less than caisim crop yields with TDS control equipment, which is in an average of 49.4 grams/plant.

Presidential Green Chemistry Challenge: 1996 Greener Synthetic Pathways Award

Science.gov (United States)

Presidential Green Chemistry Challenge 1996 award winner, Monsanto Company, developed a safer synthesis for DSIDA, a key building block for the herbicide RoundUp. The synthesis uses no ammonia, cyanide, or formaldehyde.

Impact of the ovarian cycle and pregnancy on plasma chemistry values in ewes.

Science.gov (United States)

Zywicki, Micaela E; Blohowiak, Sharon E; Magness, Ronald R; Segar, Jeffrey L; Kling, Pamela J

2018-03-01

Normative data for plasma chemistry values in pregnant and non-pregnant reproductive age ewes are scant. Availability of data would aid monitoring of ewe health for both research and veterinary medicine. We determined specific plasma chemistry 95% confidence reference intervals (RIs) in non-pregnant and pregnant ewes. Mixed Western-breed ewes were grouped based on phase of ovarian cycle: luteal ( n = 15), follicular ( n = 17), or late-gestation pregnant ( n = 102). Plasma samples were collected for analysis on a commercial biochemical analyzer. For RIs, chemistry panels for the 3 groups of ewes included nutrients and metabolites (glucose, triglycerides, cholesterol, urea, creatinine, total protein, albumin, and bilirubin), enzymes (lactate dehydrogenase, aspartate transaminase, gamma-glutamyl transferase, alanine aminotransferase, and alkaline phosphatase [ALP]), and micronutrients (calcium, phosphorus, iron, sodium, potassium, and chloride). Sample chemistry values for glucose and total protein in pregnant ewes were lower than in follicular ewes; cholesterol was lower in pregnant and luteal ewes than in follicular ewes. In addition, total bilirubin in pregnant ewes differed from that in luteal ewes, and that in follicular ewes also differed from luteal ewes. ALP in pregnant ewes was higher than other groups; phosphorus in pregnant ewes was lower than in luteal ewes. Iron was higher in pregnant ewes than in luteal ewes, with iron in luteal ewes lower than in follicular ewes. These data provide clinical RIs comparing pregnant and non-pregnant ewes for use in monitoring ewe health in both human research and veterinary medicine.

An ideal teaching program of nuclear chemistry in the undergraduate chemistry curriculum

International Nuclear Information System (INIS)

Uenak, T.

2009-01-01

It is well known that several reports on the common educational problems of nuclear chemistry have been prepared by certain groups of experts from time to time. According to very important statements in these reports, nuclear chemistry and related courses generally do not take sufficient importance in undergraduate chemistry curricula and it was generally proposed that nuclear chemistry and related courses should be introduced into undergraduate chemistry curricula at universities worldwide. Starting from these statements, an ideal program in an undergraduate chemistry curriculum was proposed to be introduced into the undergraduate chemistry program at the Department of Chemistry, Ege University, in Izmir, Turkey during the regular updating of the chemistry curriculum. Thus, it has been believed that this Department of Chemistry has recently gained an ideal teaching program in the field of nuclear chemistry and its applications in scientific, industrial, and medical sectors. In this contribution, the details of this program will be discussed. (author)

Assessment of EPRI water chemistry guidelines for new nuclear power plants

International Nuclear Information System (INIS)

Reid Richard; Kim Karen; McCree, Anisa; Eaker, Richard; Sawochka, Steve; Giannelli, Joe

2012-09-01

judged to be capable of maintaining water chemistry in accordance with existing EPRI water chemistry guidelines. However, it is important to resolve inconsistencies and knowledge gaps identified in the assessments to ensure water chemistry control guidance is optimized for the new plant designs. Additionally, the current EPRI guidelines do not specifically address water chemistry controls during pre-operational system lay-up, Hot Functional Testing, initial plant start up and early plant operations. Optimized water chemistry controls during these phases can provide significant long-term benefits in both equipment reliability and source term minimization. (authors)

Aggregated filter-feeding consumers alter nutrient limitation: consequences for ecosystem and community dynamics.

Science.gov (United States)

Atkinson, Carla L; Vaughn, Caryn C; Forshay, Kenneth J; Cooper, Joshua T

2013-06-01

Nutrient cycling is a key process linking organisms in ecosystems. This is especially apparent in stream environments in which nutrients are taken up readily and cycled through the system in a downstream trajectory. Ecological stoichiometry predicts that biogeochemical cycles of different elements are interdependent because the organisms that drive these cycles require fixed ratios of nutrients. There is growing recognition that animals play an important role in biogeochemical cycling across ecosystems. In particular, dense aggregations of consumers can create biogeochemical hotspots in aquatic ecosystems via nutrient translocation. We predicted that filter-feeding freshwater mussels, which occur as speciose, high-biomass aggregates, would create biogeochemical hotspots in streams by altering nutrient limitation and algal dynamics. In a field study, we manipulated nitrogen and phosphorus using nutrient-diffusing substrates in areas with high and low mussel abundance, recorded algal growth and community composition, and determined in situ mussel excretion stoichiometry at 18 sites in three rivers (Kiamichi, Little, and Mountain Fork Rivers, south-central United States). Our results indicate that mussels greatly influence ecosystem processes by modifying the nutrients that limit primary productivity. Sites without mussels were N-limited with -26% higher relative abundances of N-fixing blue-green algae, while sites with high mussel densities were co-limited (N and P) and dominated by diatoms. These results corroborated the results of our excretion experiments; our path analysis indicated that mussel excretion has a strong influence on stream water column N:P. Due to the high N:P of mussel excretion, strict N-limitation was alleviated, and the system switched to being co-limited by both N and P. This shows that translocation of nutrients by mussel aggregations is important to nutrient dynamics and algal species composition in these rivers. Our study highlights the

Feedback interactions between trace metal nutrients and phytoplankton in the ocean

Directory of Open Access Journals (Sweden)

William eSunda

2012-06-01

Full Text Available In addition to control by major nutrient elements (nitrogen, phosphorus, and silicon the productivity and species composition of marine phytoplankton communities are affected by a number of trace metal nutrients (iron, zinc, cobalt, manganese, copper, and cadmium. Of these, iron exerts the greatest limiting influence on carbon fixation rates and has the greatest effect on algal species diversity. It also plays an important role in limiting di-nitrogen (N2 fixation rates, and thus exerts an important influence on ocean inventories of biologically available fixed nitrogen. Because of these effects, iron is thought to play a key role in controlling the biological cycles of carbon and nitrogen in the ocean, including the biological transfer of carbon to the deep sea, the so-called biological CO2 pump, which helps regulate atmospheric CO2 levels and CO2-linked global warming. Other trace metal nutrients (zinc, cobalt, copper, and manganese have a lesser effect on productivity; but may exert an important influence on the species composition of algal communities because of large differences in metal requirements among algal species. The interactions between trace metals and ocean plankton are reciprocal: not only do the metals affect the plankton, but the plankton regulate the distributions, chemical speciation, and cycling of these metals through cellular uptake and regeneration processes, downward flux of biogenic particles, cellular release of organic chelators, and mediation of redox reactions. This two way interaction has influenced not only the biology and chemistry of the modern ocean, but has had a profound influence on biogeochemistry of the ocean and earth system as a whole, and on the evolution marine and terrestrial biology over geologic history.

Standard and hydrazine water chemistry in primary circuit of VVER 440 units

International Nuclear Information System (INIS)

Burclova, J.

1992-01-01

Standard ammonia-potassium-boron water chemistry of 8 units with VVER 440 in CSFR is discussed as well as the corrosion product activity in the coolant during steady state and shut-down period and surface activity, dose rate build-up and occupational radiation exposure. Available data on hydrazine application (USSR, Hungary) indicate the possibility of the radiation field decreasing. Nevertheless the detailed analysis of 55 cycles of operation under standard water chemistry in Czechoslovakia allows to expect the comparable results for both water chemistries. (author)

Cooling tower make-up water processing for nuclear power plants: a comparison

Energy Technology Data Exchange (ETDEWEB)

Andres, O; Flunkert, F; Hampel, G; Schiffers, A [Rheinisch-Westfaelisches Elektrizitaetswerk A.G., Essen (Germany, F.R.)

1977-01-01

In water-cooled nuclear power plants, 1 to 2% of the total investment costs go to cooling tower make-up water processing. The crude water taken from rivers or stationary waters for cooling must be sufficiently purified regarding its content of solids, carbonate hardness and corrosive components so as to guarantee an operation free of disturbances. At the same time, the processing methods must be selected for operational-economic reasons in such a manner that waste water and waste problems are kept small regarding environmental protection. The various parameters described have a decisive influence on the processing methods of the crude water, individual processes (filtration, sedimentation, decarbonization) are described, circuit possibilities for cooling water systems are compared and the various processes are analyzed and compared with regard to profitableness and environmental compatability.

Recycle of Inorganic Nutrients for Hydroponic Crop Production Following Incineration of Inedible Biomass

Science.gov (United States)

Bubenheim, David L.; Wignarajah, Kanapathipillai; Kliss, Mark H. (Technical Monitor)

1996-01-01

Recovery of resources from waste streams is essential for future implementation and reliance on a regenerative life support system. The major waste streams of concern are from human activities and plant wastes. Carbon, water and inorganics are the primary desired raw materials of interest. The goal of resource recovery is maintenance of product quality to insure support of reliable and predictable levels of life support function performance by the crop plant component. Further, these systems must be maintained over extended periods of time, requiring maintenance of nutrient solutions to avoid toxicity and deficiencies. Today, reagent grade nutrients are used to make nutrient solutions for hydroponic culture and these solutions are frequently changed during the life cycle or sometimes managed for only one crop life cycle. The focus of this study was to determine the suitability of the ash product following incineration of inedible biomass as a source of inorganic nutrients for hydroponic crop production. Inedible wheat biomass was incinerated and ash quality characterized. The incinerator ash was dissolved in adequate nitric acid to establish a consistent nitrogen concentration in all nutrient solution treatments. Four experimental nutrient treatments were included: control, ash only, ash supplemented to match control, and ash only quality formulated with reagent grade chemicals. When nutrient solutions are formulated using only ash following-incineration of inedible biomass, a balance in solution is established representing elemental retention following incineration and nutrient proportions present in the original biomass. The resulting solution is not identical to the control. This imbalance resulted in suppression of crop growth. When the ash is supplemented with nutrients to establish the same balance as in the control, growth is identical to the control. The ash appears to carry no phytotoxic materials. Growth in solution formulated with reagent grade chemicals

USDA's National Food and Nutrient Analysis Program (NFNAP) produces high-quality data for USDA food composition databases: Two decades of collaboration.

Science.gov (United States)

Haytowitz, David B; Pehrsson, Pamela R

2018-01-01

For nearly 20years, the National Food and Nutrient Analysis Program (NFNAP) has expanded and improved the quantity and quality of data in US Department of Agriculture's (USDA) food composition databases (FCDB) through the collection and analysis of nationally representative food samples. NFNAP employs statistically valid sampling plans, the Key Foods approach to identify and prioritize foods and nutrients, comprehensive quality control protocols, and analytical oversight to generate new and updated analytical data for food components. NFNAP has allowed the Nutrient Data Laboratory to keep up with the dynamic US food supply and emerging scientific research. Recently generated results for nationally representative food samples show marked changes compared to previous database values for selected nutrients. Monitoring changes in the composition of foods is critical in keeping FCDB up-to-date, so that they remain a vital tool in assessing the nutrient intake of national populations, as well as for providing dietary advice. Published by Elsevier Ltd.

Yield Gap, Indigenous Nutrient Supply and Nutrient Use Efficiency for Maize in China

Science.gov (United States)

Xu, Xinpeng; Liu, Xiaoyan; He, Ping; Johnston, Adrian M.; Zhao, Shicheng; Qiu, Shaojun; Zhou, Wei

2015-01-01

Great achievements have been attained in agricultural production of China, while there are still many difficulties and challenges ahead that call for put more efforts to overcome to guarantee food security and protect environment simultaneously. Analyzing yield gap and nutrient use efficiency will help develop and inform agricultural policies and strategies to increase grain yield. On-farm datasets from 2001 to 2012 with 1,971 field experiments for maize (Zea mays L.) were collected in four maize agro-ecological regions of China, and the optimal management (OPT), farmers’ practice (FP), a series of nutrient omission treatments were used to analyze yield gap, nutrient use efficiency and indigenous nutrient supply by adopting meta-analysis and ANOVA analysis. Across all sites, the average yield gap between OPT and FP was 0.7 t ha-1, the yield response to nitrogen (N), phosphorus (P), and potassium (K) were 1.8, 1.0, and 1.2 t ha-1, respectively. The soil indigenous nutrient supply of N, P, and K averaged 139.9, 33.7, and 127.5 kg ha-1, respectively. As compared to FP, the average recovery efficiency (RE) of N, P, and K with OPT increased by percentage point of 12.2, 5.5, and 6.5, respectively. This study indicated that there would be considerable potential to further improve yield and nutrient use efficiency in China, and will help develop and inform agricultural policies and strategies, while some management measures such as soil, plant and nutrient are necessary and integrate with advanced knowledge and technologies. PMID:26484543

Yield Gap, Indigenous Nutrient Supply and Nutrient Use Efficiency for Maize in China.

Directory of Open Access Journals (Sweden)

Xinpeng Xu

Full Text Available Great achievements have been attained in agricultural production of China, while there are still many difficulties and challenges ahead that call for put more efforts to overcome to guarantee food security and protect environment simultaneously. Analyzing yield gap and nutrient use efficiency will help develop and inform agricultural policies and strategies to increase grain yield. On-farm datasets from 2001 to 2012 with 1,971 field experiments for maize (Zea mays L. were collected in four maize agro-ecological regions of China, and the optimal management (OPT, farmers' practice (FP, a series of nutrient omission treatments were used to analyze yield gap, nutrient use efficiency and indigenous nutrient supply by adopting meta-analysis and ANOVA analysis. Across all sites, the average yield gap between OPT and FP was 0.7 t ha-1, the yield response to nitrogen (N, phosphorus (P, and potassium (K were 1.8, 1.0, and 1.2 t ha-1, respectively. The soil indigenous nutrient supply of N, P, and K averaged 139.9, 33.7, and 127.5 kg ha-1, respectively. As compared to FP, the average recovery efficiency (RE of N, P, and K with OPT increased by percentage point of 12.2, 5.5, and 6.5, respectively. This study indicated that there would be considerable potential to further improve yield and nutrient use efficiency in China, and will help develop and inform agricultural policies and strategies, while some management measures such as soil, plant and nutrient are necessary and integrate with advanced knowledge and technologies.

Yield Gap, Indigenous Nutrient Supply and Nutrient Use Efficiency for Maize in China.

Science.gov (United States)

Xu, Xinpeng; Liu, Xiaoyan; He, Ping; Johnston, Adrian M; Zhao, Shicheng; Qiu, Shaojun; Zhou, Wei

2015-01-01

Great achievements have been attained in agricultural production of China, while there are still many difficulties and challenges ahead that call for put more efforts to overcome to guarantee food security and protect environment simultaneously. Analyzing yield gap and nutrient use efficiency will help develop and inform agricultural policies and strategies to increase grain yield. On-farm datasets from 2001 to 2012 with 1,971 field experiments for maize (Zea mays L.) were collected in four maize agro-ecological regions of China, and the optimal management (OPT), farmers' practice (FP), a series of nutrient omission treatments were used to analyze yield gap, nutrient use efficiency and indigenous nutrient supply by adopting meta-analysis and ANOVA analysis. Across all sites, the average yield gap between OPT and FP was 0.7 t ha-1, the yield response to nitrogen (N), phosphorus (P), and potassium (K) were 1.8, 1.0, and 1.2 t ha-1, respectively. The soil indigenous nutrient supply of N, P, and K averaged 139.9, 33.7, and 127.5 kg ha-1, respectively. As compared to FP, the average recovery efficiency (RE) of N, P, and K with OPT increased by percentage point of 12.2, 5.5, and 6.5, respectively. This study indicated that there would be considerable potential to further improve yield and nutrient use efficiency in China, and will help develop and inform agricultural policies and strategies, while some management measures such as soil, plant and nutrient are necessary and integrate with advanced knowledge and technologies.

Water chemistry

International Nuclear Information System (INIS)

Hofstetter, K.J.; Baston, V.F.

1986-01-01

Prior to the accident, the coolants in the primary and secondary systems were within normal chemistry specifications for an operating pressurized water reactor with once-through steam generators. During and immediately after the accident, additional boric acid and sodium hydroxide were added to the primary coolant for control of criticality and radioiodine solubility. A primary to secondary leak developed contaminating the water in one steam generator. For about 5 years after the accident, the primary coolant was maintained at 3800 +. 100 ppm boron and 1000 +. 100 ppm sodium concentrations. Dissolved oxygen was maintained 7.5, corrosion caused by increased dissolved oxygen levels (up to 8 ppm) and higher chloride ion content (up to 5 ppm) is minimized. Chemical control of dissolved oxygen was discontinued and the coolant was processed. Prior to removal of the reactor vessel head, the boron concentration in the coolant was increased to ≅ 5000 ppm to support future defueling operations. Decontamination of the accident generated water is described in terms of contaminated water management. In addition, the decontamination and chemical lay-up conditions for the secondary system are presented along with an overview of chemical management at TMI-2

BWR Water Chemistry Guidelines: 1993 Revision, Normal and hydrogen water chemistry

International Nuclear Information System (INIS)

Karlberg, G.; Goddard, C.; Fitzpatrick, S.

1994-02-01

The goal of water chemistry control is to extend the operating life of the reactor and rector coolant system, balance-of-plant components, and turbines while simultaneously controlling costs to safeguard the continued economic viability of the nuclear power generation investment. To further this goal an industry committee of chemistry personnel prepared guidelines to identify the benefits, risks, and costs associated with water chemistry in BWRs and to provide a template for an optimized water chemistry program. This document replaces the BWR Normal Water Chemistry Guidelines - 1986 Revision and the BWR Hydrogen Water Chemistry Guidelines -- 1987 Revision. It expands on the previous guidelines documents by covering the economic implications of BWR water chemistry control

Investigation of Varied Strontium-Transuranic Precipitation Chemistries for Crossflow

International Nuclear Information System (INIS)

Nash, C.A.

2000-01-01

Precipitation chemistries for strontium and transuranic (TRU) removal have been tested for crossflow filterability and lanthanide removal with simulants of Hanford tank 241-AN-107 supernate. This is the initial work indicating the usefulness of a strontium and permanganate precipitation process as applied to the Hanford River Protection Project. Precipitations with both ferric and ferrous iron were shown to be at least two orders of magnitude less filterable than a 0.1 gpm/ft target average flux that was desired at the time. A precipitate from a strontium nitrate strike alone was found to filter easily and to make the desired average flux. Other chemistries tested included precipitant of lanthanum(III), nickel (II), calcium (II), and a redox chemistry using sodium permanganate. Of these chemistries a strontium and permanganate strike including calcium provided the highest filter flux compared to the other chemistries. It showed the most promise in lanthanide removal as well. This work provides a promising direction for further work to achieve both acceptable filterability and decontamination for Envelope C wastes to be treated by the Hanford River Protection Project. The work reported here was originally intended to satisfy needs for crossflow filter testing of a strontium and ferric precipitation method for treating Envelope C using a 241-AN-107 simulant

Investigation of Varied Strontium-Transuranic Precipitation Chemistries for Crossflow

Energy Technology Data Exchange (ETDEWEB)

Nash, C.A.

2000-07-27

Precipitation chemistries for strontium and transuranic (TRU) removal have been tested for crossflow filterability and lanthanide removal with simulants of Hanford tank 241-AN-107 supernate. This is the initial work indicating the usefulness of a strontium and permanganate precipitation process as applied to the Hanford River Protection Project. Precipitations with both ferric and ferrous iron were shown to be at least two orders of magnitude less filterable than a 0.1 gpm/ft target average flux that was desired at the time. A precipitate from a strontium nitrate strike alone was found to filter easily and to make the desired average flux. Other chemistries tested included precipitant of lanthanum(III), nickel (II), calcium (II), and a redox chemistry using sodium permanganate. Of these chemistries a strontium and permanganate strike including calcium provided the highest filter flux compared to the other chemistries. It showed the most promise in lanthanide removal as well. This work provides a promising direction for further work to achieve both acceptable filterability and decontamination for Envelope C wastes to be treated by the Hanford River Protection Project. The work reported here was originally intended to satisfy needs for crossflow filter testing of a strontium and ferric precipitation method for treating Envelope C using a 241-AN-107 simulant.

An Alternative Educational Approach for an Inorganic Chemistry Laboratory Course in Industrial and Chemical Engineering

Science.gov (United States)

Garces, Andres; Sanchez-Barba, Luis Fernando

2011-01-01

We describe an alternative educational approach for an inorganic chemistry laboratory module named "Experimentation in Chemistry", which is included in Industrial Engineering and Chemical Engineering courses. The main aims of the new approach were to reduce the high levels of failure and dropout on the module and to make the content match the…

Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

International Nuclear Information System (INIS)

Ryan, R.R.

1982-05-01

This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research

Chemistry-Nuclear Chemistry Division. Progress report, October 1980-September 1981

Energy Technology Data Exchange (ETDEWEB)

Ryan, R.R. (comp.)

1982-05-01

This report describes major progress in the research and development programs pursued by the Chemistry-Nuclear Chemistry Division of the Los Alamos National Laboratory during FY 1981. Topics covered include advanced analytical methods, atmospheric chemistry and transport, biochemistry, biomedical research, medical radioisotopes research, element migration and fixation, nuclear waste isolation research, inorganic and structural chemistry, isotope separation, analysis and applications, the newly established Nuclear Magnetic Resonance Center, atomic and molecular collisions, molecular spectroscopy, nuclear cosmochemistry, nuclear structure and reactions, pion charge exchange, radiochemical separations, theoretical chemistry, and unclassified weapons research.

Processing recommendations for using low-solids digestate as nutrient solution for poly-ß-hydroxybutyrate production with Synechocystis salina.

Science.gov (United States)

Meixner, K; Fritz, I; Daffert, C; Markl, K; Fuchs, W; Drosg, B

2016-12-20

Within the last decades, environmental pollution with persistent plastics steadily increased; therefore the production of biodegradable materials like poly-ß-hydroxybutyrate (PHB) is essential. Currently, PHB is produced with heterotrophic bacteria from crops. This leads to competition with food and feed production, which can be avoided by using photoautotrophic cyanobacteria, as Synechocystis salina, synthesizing PHB from CO 2 at nutrient limitation. This study aims to increase the economic efficiency of PHB production with cyanobacteria by using nutrients from anaerobic digestate. First, growth and PHB production of S. salina in digestate fractions (supernatant and permeate, with/without precipitating agents) and dilutions thereof and then the scale-up (photobioreactor, 200 L working volume) were evaluated. With precipitated and centrifuged digestate diluted 1/3 the highest biomass (1.55gL -1 ) and PHB concentrations (95.4mgL -1 ), being 78% of those in mineral media, were achieved. In the photobioreactor-experiments biomass (1.63gL -1 ) and PHB concentrations (88.7mgL -1 ), being 79% and 72% of those in mineral medium, were reached, but in a cultivation time 10days longer than in mineral medium. The possibility to use digestate as sustainable and low cost nutrient solution for microalgae cultivation and photoautotrophic PHB production, instead of applying it on fields or processing it to achieve discharge limits, makes this application a highly valid option. Copyright © 2016 Elsevier B.V. All rights reserved.

An expanded framework to define and measure shared decision-making in dialogue: A 'top-down' and 'bottom-up' approach.

Science.gov (United States)

Callon, Wynne; Beach, Mary Catherine; Links, Anne R; Wasserman, Carly; Boss, Emily F

2018-03-11

We aimed to develop a comprehensive, descriptive framework to measure shared decision making (SDM) in clinical encounters. We combined a top-down (theoretical) approach with a bottom-up approach based on audio-recorded dialogue to identify all communication processes related to decision making. We coded 55 pediatric otolaryngology visits using the framework and report interrater reliability. We identified 14 clinician behaviors and 5 patient behaviors that have not been previously described, and developed a new SDM framework that is descriptive (what does happen) rather than normative (what should happen). Through the bottom-up approach we identified three broad domains not present in other SDM frameworks: socioemotional support, understandability of clinician dialogue, and recommendation-giving. We also specify the ways in which decision-making roles are assumed implicitly rather than discussed explicitly. Interrater reliability was >75% for 92% of the coded behaviors. This SDM framework allows for a more expansive understanding and analysis of how decision making takes place in clinical encounters, including new domains and behaviors not present in existing measures. We hope that this new framework will bring attention to a broader conception of SDM and allow researchers to further explore the new domains and behaviors identified. Copyright © 2018. Published by Elsevier B.V.

Synthesis of fused bicyclic piperidines: potential bioactive templates for medicinal chemistry.

Science.gov (United States)

Zhou, Jinglan; Campbell-Conroy, Erica L; Silina, Alina; Uy, Johnny; Pierre, Fabrice; Hurley, Dennis J; Hilgraf, Nicole; Frieman, Bryan A; DeNinno, Michael P

2015-01-02

An array of six pyridyl-substituted fused bicyclic piperidines was prepared as novel cores for medicinal chemistry. For maximum diversity, the size of the fused ring varied from three to six atoms and contained up to two oxygen atoms. The pyridine ring was incorporated to improve physicochemical properties and to challenge the robustness of the chemistry. The presence of the pyridine did interfere with our initial approaches to these molecules, and in several instances, a blocking strategy had to be employed. These new scaffolds possess high sp3 character and may prove useful in multiple medicinal chemistry applications.

Handbook on process and chemistry on nuclear fuel reprocessing

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Atsuyuki [Tokyo Univ., Tokyo (Japan); Asakura, Toshihide; Adachi, Takeo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; and others

2001-12-01

'Wet-type' nuclear fuel reprocessing technology, based on PUREX technology, has wide applicability as the principal reprocessing technology of the first generation, and relating technologies, waste management for example, are highly developed, too. It is quite important to establish a database summarizing fundamental information about the process and the chemistry of 'wet-type' reprocessing, because it contributes to establish and develop fuel reprocessing process and nuclear fuel cycle treating high burn-up UO{sub 2} fuel and spent MOX fuel, and to utilize 'wet-type' reprocessing technology much widely. This handbook summarizes the fundamental data on process and chemistry, which was collected and examined by 'Editing Committee of Handbook on Process and Chemistry of Nuclear Fuel Reprocessing', from FY 1993 until FY 2000. (author)